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Sample records for controlled delivery matrixes

  1. Formulation and Characterization of Matrix and Triple-Layer matrix tablets for Controlled Delivery of Metoprolol tartrate

    OpenAIRE

    Izhar Ahmed Syed; Lakshmi Narsu Mangamoori; Yamsani Madhusudan Rao

    2011-01-01

    In the present study matrix and triple layer matrix tablets of metoprolol tartrate were formulated by using xanthan gum as the matrix forming agent and Sodium Carboxy Methyl Cellulose (Na CMC) as barrier layers. The prepared tablets were analysed for their hardness, friability, drug content and in-vitro drug release studies. Marked differences in dissolution characteristics of (M3) and (M3L3) were observed and showed a significant difference statistically. Mean dissolution time (MDT) for M3 a...

  2. Formulation design and development of matrix diffusion controlled transdermal drug delivery of glimepiride

    Directory of Open Access Journals (Sweden)

    Akram MR

    2018-02-01

    Full Text Available Muhammad Rouf Akram,1 Mahmood Ahmad,1 Asad Abrar,1 Rai Muhammad Sarfraz,2 Asif Mahmood3 1Faculty of Pharmacy & Alternative Medicine, The Islamia University of Bahawalpur, Bahawalpur, Pakistan; 2Faculty of Pharmacy, University of Sargodha, Sargodha, Pakistan; 3Faculty of Pharmacy, University of Lahore, Lahore, Pakistan Background: The present work was conducted to prepare and evaluate transdermal patches with optimization of suitable polymeric blend of poly(meth acrylates (Eudragit® (Ammonio Methacrylate Copolymer Ph Eur for sustained transdermal delivery of glimepiride. Method: Polymeric matrix transdermal films were prepared by using Ammonio Methacrylate Copolymer Ph Eur RL 100 and Ammonio Methacrylate Copolymer Ph Eur RS 100 as the film former, and dibutyl phthalate (30% w/w as the plasticizer. Patches were characterized by physical appearance, thickness, weight variation, folding endurance, percentage erosion, swelling index, moisture content, and moisture uptake capacity. Fourier transform infrared spectroscopic studies and differential scanning calorimetry analysis of physical mixtures of contents were performed to identify any chemical and physical interaction between drug and excipients. Five different enhancers (isopropyl myristate [IPM], Span® 80, Tween® 20, eucalyptus oil, and limonene were employed at three different concentrations of polymer (2%, 5%, and 10% w/w in order to enhance permeation through rabbit skin. In vitro drug release studies were performed at pH 7.4, and scanning electron microscopy was conducted to elucidate surface morphology before and after the drug release. In vitro permeation studies through rabbit skin were performed on Franz diffusion cells and permeation kinetics followed the Higuchi model. Results: Results of in vitro permeation studies revealed that these enhancers not only increased drug release but also augmented the skin permeation of glimepiride. Conclusion: IPM was the most effective enhancer with

  3. Controlled protein delivery from electrospun non-wovens: novel combination of protein crystals and a biodegradable release matrix.

    Science.gov (United States)

    Puhl, Sebastian; Li, Linhao; Meinel, Lorenz; Germershaus, Oliver

    2014-07-07

    Poly-ε-caprolactone (PCL) is an excellent polymer for electrospinning and matrix-controlled drug delivery combining optimal processability and good biocompatibility. Electrospinning of proteins has been shown to be challenging via the use of organic solvents, frequently resulting in protein unfolding or aggregation. Encapsulation of protein crystals represents an attractive but largely unexplored alternative to established protein encapsulation techniques because of increased thermodynamic stability and improved solvent resistance of the crystalline state. We herein explore the electrospinning of protein crystal suspensions and establish basic design principles for this novel type of protein delivery system. PCL was deployed as a matrix, and lysozyme was used as a crystallizing model protein. By rational combination of lysozyme crystals 0.7 or 2.1 μm in diameter and a PCL fiber diameter between 1.6 and 10 μm, release within the first 24 h could be varied between approximately 10 and 100%. Lysozyme loading of PCL microfibers between 0.5 and 5% was achieved without affecting processability. While relative release was unaffected by loading percentage, the amount of lysozyme released could be tailored. PCL was blended with poly(ethylene glycol) and poly(lactic-co-glycolic acid) to further modify the release rate. Under optimized conditions, an almost constant lysozyme release over 11 weeks was achieved.

  4. Chronotherapeutic drug delivery of Tamarind gum, Chitosan and Okra gum controlled release colon targeted directly compressed Propranolol HCl matrix tablets and in-vitro evaluation.

    Science.gov (United States)

    Newton, A M J; Indana, V L; Kumar, Jatinder

    2015-08-01

    The main objective of this investigation is to develop a chronotherapeutic drug delivery of various natural polymers based colon targeted drug delivery systems to treat early morning sign in BP. The polymers such as Tamarind gum, Okra gum and Chitosan were used in the formulation design. A model drug Propranolol HCl was incorporated in the formulation in order to assess the controlled release and time dependent release potential of various natural polymers. A novel polymer Tamarind gum was extracted and used as a prime polymer in this study to prove the superiority of this polymer over other leading natural polymer. Propranolol HCl was used as a model drug which undergoes hepatic metabolism and witnesses the poor bioavailability. The matrix tablets of Propranolol HCl were prepared by direct compression. The tablets were evaluated for various quality control parameters and found to be within the limits. Carbopol 940 was used as an auxiliary polymer to modify the drug release and physicochemical characteristics of the tablets. The in vitro release studies were performed in 0.1N HCl for 1.5h, followed by pH 6.8 phosphate buffer for 2h and pH 7.4 phosphate buffer till maximum amount of drug release. The in vitro release profile of the formulations were fitted with various pharmacokinetic mathematical models and analyzed for release profile. The formulations prepared with Tamarind gum prolonged the release for an extended period of time compared to other polymer based formulation and showed an excellent compression characteristic. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Biological studies of matrix metalloproteinase sensitive drug delivery systems

    DEFF Research Database (Denmark)

    Johansen, Pia Thermann

    for delivery of drugs to specific tissues or cells utilizing biological knowledge of cancer tissue is getting increased attention. In this thesis a novel matrix metalloproteinase-2 (MMP-2) sensitive poly-ethylene glycol (PEG) coated liposomal drug delivery system for treatment of cancer was developed....... The system exploits the increased MMP-2 activity present in tumor tissue as a site-specific trigger of liposomal activation and controlled drug release after accumulation due to the enhanced permeability and retention effect. Enzymatic activity of MMP-2 results in shedding of a novel PEG coating, consisting...... of a negatively charged lipopeptide-PEG conjugates containing a MMP-2 cleavable peptide, which leads to cationic liposomes with enhanced ability to interact with negatively charged cell membranes. Activation of the liposomal formulation developed here resulted in enhanced association of liposomes with cancer...

  6. Modeling the modified drug release from curved shape drug delivery systems - Dome Matrix®.

    Science.gov (United States)

    Caccavo, D; Barba, A A; d'Amore, M; De Piano, R; Lamberti, G; Rossi, A; Colombo, P

    2017-12-01

    The controlled drug release from hydrogel-based drug delivery systems is a topic of large interest for research in pharmacology. The mathematical modeling of the behavior of these systems is a tool of emerging relevance, since the simulations can be of use in the design of novel systems, in particular for complex shaped tablets. In this work a model, previously developed, was applied to complex-shaped oral drug delivery systems based on hydrogels (Dome Matrix®). Furthermore, the model was successfully adopted in the description of drug release from partially accessible Dome Matrix® systems (systems with some surfaces coated). In these simulations, the erosion rate was used asa fitting parameter, and its dependence upon the surface area/volume ratio and upon the local fluid dynamics was discussed. The model parameters were determined by comparison with the drug release profile from a cylindrical tablet, then the model was successfully used for the prediction of the drug release from a Dome Matrix® system, for simple module configuration and for module assembled (void and piled) configurations. It was also demonstrated that, given the same initial S/V ratio, the drug release is independent upon the shape of the tablets but it is only influenced by the S/V evolution. The model reveals itself able to describe the observed phenomena, and thus it can be of use for the design of oral drug delivery systems, even if complex shaped. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. A suppository-base-matrix tablet for time-dependent colon-specific delivery system

    Directory of Open Access Journals (Sweden)

    Meijuan Zou

    2014-09-01

    Full Text Available Our research has focused on the main design features and release performances of time-dependent colon-specific (TDCS delivery tablets, which relies on the relative constancy that is observed in the small intestinal transit time of dosage forms. But inflammatory bowel disease(IBD)can affect the transit time, and usually results in watery stool. Compared to the TDCS and wax-matrix TDCS tablet, a promising time-dependent colon-specific delivery system was investigated. In our study, a suppository-base-matrix coated tablet was evaluated. Water soluble suppository-base helps the expansion of tablet, facilitates uniform film dissolution and achives high osmotic pressure. Combining the expansion of carboxymethyl starch sodium (CMS-Na and the moisture absorption of NaCl, the coated TDCS tablet obtained a burst and targeted drug delivery system. A very good correlation between in vitro drug release and in vivo outcome was observed. This TDCS coated tablet provides a promising strategy to control drug release to the desired lower gastrointestinal region.

  8. Enhanced Controlled Transdermal Delivery of Torasemide Using ...

    African Journals Online (AJOL)

    Purpose: To develop an ethylene-vinyl acetate (EVA) matrix system containing a permeation enhancer for enhanced transdermal delivery of torasemide. Methods: The solubility of torasemide was studied at various volume fraction of polyethylene glycol (PEG) 400. The effect of drug concentration was tested at 1.0, 2.0 and ...

  9. Magnetically-responsive, multifunctional drug delivery nanoparticles for elastic matrix regenerative repair.

    Science.gov (United States)

    Sivaraman, Balakrishnan; Swaminathan, Ganesh; Moore, Lee; Fox, Jonathan; Seshadri, Dhruv; Dahal, Shataakshi; Stoilov, Ivan; Zborowski, Maciej; Mecham, Robert; Ramamurthi, Anand

    2017-04-01

    Arresting or regressing growth of abdominal aortic aneurysms (AAAs), localized expansions of the abdominal aorta are contingent on inhibiting chronically overexpressed matrix metalloproteases (MMPs)-2 and -9 that disrupt elastic matrix within the aortic wall, concurrent with providing a stimulus to augmenting inherently poor auto-regeneration of these matrix structures. In a recent study we demonstrated that localized, controlled and sustained delivery of doxycycline (DOX; a tetracycline-based antibiotic) from poly(lactic-co-glycolic acid) nanoparticles (PLGA NPs), enhances elastic matrix deposition and MMP-inhibition at a fraction of the therapeutically effective oral dose. The surface functionalization of these NPs with cationic amphiphiles, which enhances their arterial uptake, was also shown to have pro-matrix regenerative and anti-MMP effects independent of the DOX. Based on the hypothesis that the incorporation of superparamagnetic iron oxide NPs (SPIONs) within these PLGA NPs would enhance their targetability to the AAA site under an applied external magnetic field, we sought to evaluate the functional effects of NPs co-encapsulating DOX and SPIONs (DOX-SPION NPs) on elastic matrix regeneration and MMP synthesis/activity in vitro within aneurysmal smooth muscle cell (EaRASMC) cultures. The DOX-SPION NPs were mobile under an applied external magnetic field, while enhancing elastic matrix deposition 1.5-2-fold and significantly inhibiting MMP-2 synthesis and MMP-2 and -9 activities, compared to NP-untreated control cultures. These results illustrate that the multifunctional benefits of NPs are maintained following SPION co-incorporation. Additionally, preliminary studies carried out demonstrated enhanced targetability of SPION-loaded NPs within proteolytically-disrupted porcine carotid arteries ex vivo, under the influence of an applied external magnetic field. Thus, this dual-agent loaded NP system proffers a potential non-surgical option for treating small

  10. Soy matrix drug delivery systems obtained by melt-processing techniques

    NARCIS (Netherlands)

    Vaz, C.M.; Doeveren, van P.F.N.M.; Reis, R.L.; Cunha, A.M.

    2003-01-01

    The aim of this study was to develop new soy protein drug delivery matrix systems by melt-processing techniques, namely, extrusion and injection moulding. The soy matrix systems with an encapsulated drug (theophylline, TH) were previously compounded by extrusion performed at two different pH values,

  11. Oral Drug Delivery Systems Comprising Altered Geometric Configurations for Controlled Drug Delivery

    Directory of Open Access Journals (Sweden)

    Priya Bawa

    2011-12-01

    Full Text Available Recent pharmaceutical research has focused on controlled drug delivery having an advantage over conventional methods. Adequate controlled plasma drug levels, reduced side effects as well as improved patient compliance are some of the benefits that these systems may offer. Controlled delivery systems that can provide zero-order drug delivery have the potential for maximizing efficacy while minimizing dose frequency and toxicity. Thus, zero-order drug release is ideal in a large area of drug delivery which has therefore led to the development of various technologies with such drug release patterns. Systems such as multilayered tablets and other geometrically altered devices have been created to perform this function. One of the principles of multilayered tablets involves creating a constant surface area for release. Polymeric materials play an important role in the functioning of these systems. Technologies developed to date include among others: Geomatrix® multilayered tablets, which utilizes specific polymers that may act as barriers to control drug release; Procise®, which has a core with an aperture that can be modified to achieve various types of drug release; core-in-cup tablets, where the core matrix is coated on one surface while the circumference forms a cup around it; donut-shaped devices, which possess a centrally-placed aperture hole and Dome Matrix® as well as “release modules assemblage”, which can offer alternating drug release patterns. This review discusses the novel altered geometric system technologies that have been developed to provide controlled drug release, also focusing on polymers that have been employed in such developments.

  12. Natural and synthetic biomaterials for controlled drug delivery.

    Science.gov (United States)

    Kim, Jang Kyoung; Kim, Hyung Jin; Chung, Jee-Young; Lee, Jong-Hwan; Young, Seok-Beom; Kim, Yong-Hee

    2014-01-01

    A wide variety of delivery systems have been developed and many products based on the drug delivery technology are commercially available. The development of controlled-release technologies accelerated new dosage form design by altering pharmacokinetic and pharmacodynamics profiles of given drugs, resulting in improved efficacy and safety. Various natural or synthetic polymers have been applied to make matrix, reservoir or implant forms due to the characteristics of polymers, especially ease of control for modifications of biocompatibility, biodegradation, porosity, charge, mechanical strength and hydrophobicity/hydrophilicity. Hydrogel is a hydrophilic, polymeric network capable of imbibing large amount of water and biological fluids. This review article introduces various applications of natural and synthetic polymer-based hydrogels from pharmaceutical, biomedical and bioengineering points of view.

  13. Nanofibrillar cellulose films for controlled drug delivery.

    Science.gov (United States)

    Kolakovic, Ruzica; Peltonen, Leena; Laukkanen, Antti; Hirvonen, Jouni; Laaksonen, Timo

    2012-10-01

    Nanofibrillar cellulose (NFC) (also referred to as cellulose nanofibers, nanocellulose, microfibrillated, or nanofibrillated cellulose) has gotten recent and wide attention in various research areas. Here, we report the application of nanofibrillar cellulose as a matrix-former material for long-lasting (up to three months) sustained drug delivery. Film-like matrix systems with drug loadings between 20% and 40% were produced by a filtration method. This simple production method had an entrapment efficacy>90% and offers a possibility for the film thickness adjustment as well as applicability in the incorporation of heat sensitive compounds. The films had excellent mechanical properties suitable for easy handling and shape tailoring of the drug release systems. They were characterized in terms of the internal morphology, and the physical state of the encapsulated drug. The drug release was assessed by dissolution tests, and suitable mathematical models were used to explain the releasing kinetics. The drug release was sustained for a three month period with very close to zero-order kinetics. It is assumed that the nanofibrillar cellulose film sustains the drug release by forming a tight fiber network around the incorporated drug entities. The results indicate that the nanofibrillar cellulose is a highly promising new material for sustained release drug delivery applications. Copyright © 2012 Elsevier B.V. All rights reserved.

  14. Prodrugs of gestodene for matrix-type transdermal drug delivery systems.

    Science.gov (United States)

    Lipp, R; Laurent, H; Günther, C; Riedl, J; Esperling, P; Täuber, U

    1998-09-01

    The aim of this study was to enhance the transdermal absorption of the highly active progestin gestodene from matrix type transdermal delivery systems (TDDS) by formation of prodrugs with improved matrix solubility. Gestodene esters were synthesized via acylation of the drug with the respective carboxylic anhydrides. Subsequently TDDS were produced using the solvent cast method. Selected formulations were examined with in vitro diffusion experiments using skin of nude mice. One prodrug, gestodene caproate proved to be an oil at ambient temperature and showed a very high solubilty of over 10.5% in the TDDS matrix. Within in vitro penetration studies using those systems the prodrug exhibited a significantly higher transdermal penetration rate than gestodene from reference systems. Furthermore, the prodrug was hydrolyzed to the parent drug to a high extent during the passage of the skin. Designing prodrugs to the requirements of matrix TDDS is an efficient way of enhancing the transdermal drug flux rate.

  15. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    Science.gov (United States)

    Gao, Lin; Sun, Jihong; Li, Yuzhen

    2011-08-01

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation ft= ktn was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties.

  16. Human Homeostatic Control Matrix in Norm

    Directory of Open Access Journals (Sweden)

    Alexander G. Kruglov

    2016-09-01

    Full Text Available We undertook our research to study and systemize the relationship between hemodynamics and biochemical parameters of arterial and venous blood in healthy people. Hemodynamic and biochemical characteristics were obtained through a probe by using catheterization in various vascular areas (aorta, brain, heart, lungs, and liver. Correlation and factor analyses were conducted to study the relationship between the obtained characteristics of the regional and systemic blood flow. Due to the nature of the correlation analysis, the significant (p<0.05 relation signs (+, 0, - without regard to their power were considered. The obtained results suggested that there are sets of both intra-organ and system regulatory relationships between metabolic and hemodynamic characteristics. The complex of relationships among the studied parameters makes it possible to maintain the homeostatic equilibrium in the body. The psychophysiological control system includes the subsystems we described: 1 the cardiac-hepatic-pulmonary complex having properties of the metabolic and hemodynamic information field providing biological stability of the homeostasis; any significant imbalance of its elements triggers afferent information flows actualizing an afferent synthesis; 2 the mind forming gradient patterns of targeted behavior to eliminate metabolic imbalance, to achieve goals both as coded biological parameters and as the highest forms of behavior, to reach the ultimate goal: parametric, homeostatic equilibrium in the “biosphere” of the human body. By using the results of our research and the complex of dynamic relationships in human homeostasis, we built a homeostatic control matrix (HCM.

  17. Cascaded PID controller for anaesthesia delivery.

    Science.gov (United States)

    Simalatsar, Alena; Guidi, Monia; Buclin, Thierry

    2016-08-01

    The technologies for continuous measurement of the anaesthetic agents circulating in body fluids are not mature yet, though some preliminary prototypes exist already. We present a control algorithm that based on the real measurement of propofol plasma concentration may adjust the delivery rate. This opens a possibility for a safer anesthesia when the technologies for online measurement of drug concentration will be mature enough to be combined with our model.

  18. Aircraft Landing and Attitude Control Using Dynamic Matrix Control

    Directory of Open Access Journals (Sweden)

    George Cristian Calugaru

    2017-06-01

    Full Text Available This paper proposes a method for an efficient control of the aircraft landing and attitude through Dynamic Matrix Control. The idea of MPC structures used in aircraft control has been well established during the last few years, but some aspects require further investigation. With this in mind, the paper proposes structures for aircraft landing and aircraft attitude control by using single DMC controllers for landing and respectively one DMC controller for each of the attitude axis (pitch attitude hold, bank angle hold and heading hold. The model used for analysis of the aircraft landing structure is based on the last phase of landing. Also, the model used to illustrate the attitude control is that of a pitch attitude hold system of a N250-100 aircraft. Simulations are performed for a variety of control and prediction horizons, taking into account the possibility of adding a weighting factor for the control actions. Apart from separate studies on step reference variations, for some use cases, a generic reference trajectory is provided as a control purpose of the system. Results show a better performance of the proposed method in terms of control surface transition and protection of the actuators involved and a better time response in stabilizing the aircraft attitude. Overall, the aspects shown ensure an improved aircraft attitude control and landing stabilization.

  19. Plasmon resonant liposomes for controlled drug delivery

    Science.gov (United States)

    Knights-Mitchell, Shellie S.; Romanowski, Marek

    2015-03-01

    Nanotechnology use in drug delivery promotes a reduction in systemic toxicity, improved pharmacokinetics, and better drug bioavailability. Liposomes continue to be extensively researched as drug delivery systems (DDS) with formulations such as Doxil® and Ambisome® approved by FDA and successfully marketed in the United States. However, the limited ability to precisely control release of active ingredients from these vesicles continues to challenge the broad implementation of this technology. Moreover, the full potential of the carrier to sequester drugs until it can reach its intended target has yet to be realized. Here, we describe a liposomal DDS that releases therapeutic doses of an anticancer drug in response to external stimulus. Earlier, we introduced degradable plasmon resonant liposomes. These constructs, obtained by reducing gold on the liposome surface, facilitate spatial and temporal release of drugs upon laser light illumination that ultimately induces an increase in temperature. In this work, plasmon resonant liposomes have been developed to stably encapsulate and retain doxorubicin at physiological conditions represented by isotonic saline at 37o C and pH 7.4. Subsequently, they are stimulated to release contents either by a 5o C increase in temperature or by laser illumination (760 nm and 88 mW/cm2 power density). Successful development of degradable plasmon resonant liposomes responsive to near-infrared light or moderate hyperthermia can provide a new delivery method for multiple lipophilic and hydrophilic drugs with pharmacokinetic profiles that limit clinical utility.

  20. Damar Batu as a novel matrix former for the transdermal drug delivery: in vitro evaluation.

    Science.gov (United States)

    Mundada, A S; Avari, J G

    2009-09-01

    Damar Batu (DB) is a novel film-forming biomaterial obtained from Shorea species, evaluated in this study for its potential application in transdermal drug delivery system. DB was characterized initially in terms of acid value, softening point, molecular weight (M(w)), polydispersity index (M(w)/M(n)), and glass transition temperature (T(g)). Neat, plasticized films of DB were investigated for mechanical properties. The biomaterial was further investigated as a matrix-forming agent for transdermal drug delivery system. Developed matrix-type transdermal patches were evaluated for thickness and weight uniformity, folding endurance, drug content, in vitro drug release study, and skin permeation study. On the basis of in vitro drug release and in vitro skin permeation performance, formulation containing DB/Eudragit RL100 (60 : 40) was found to be better than other formulations and was selected as the optimized formulation. IR analysis of physical mixture of drug and polymer and thin layer chromatography study exhibited compatibility between drug and polymer. From the outcome of this study, it can be concluded that applying suitable adhesive layer and backing membrane-developed DB/ERL100, transdermal patches can be of potential therapeutic use.

  1. Decal bone matrix as a local antibiotic delivery vehicle in a MRSA-infected bone model: An experimental study

    Directory of Open Access Journals (Sweden)

    Saraf Shyam

    2010-01-01

    Full Text Available Background: Polymethyl methacrylate (PMMA antibiotic beads though have proved their utility as a local antibiotic delivery system, however, there are limitations. Decalcified bone matrix (DBM as a vehicle of antibiotics can serve the purpose, provided a minimum inhibitory concentration is sustained. Healing of the defect and avoiding the second surgery is another advantage. We studied the DBM as the delivery vehicle for vancomycin in controlling the methicillin-resistant Staphylococcus aureus (MRSA osteomyelitis as well as healing of the cavity simultaneously in an experimental study. Materials and Methods: An in vitro study was conducted to optimize vancomycin impregnation in the DBM. For the in vivo study, a unicortical defect was created in the metaphysis of the distal femur in 18 rabbits. After contaminating the defect with MRSA, rabbits were divided into three groups. Group I (eight limbs received no graft. Defects in group II (11 limbs were filled with plain DBM chips and in group III (14 limbs, cavities were implanted with vancomycin-impregnated decal bone chips. Rabbits were assessed by clinical, radiological, histological, gross examination and bacterial load assay. High Performance Liquid Chromatography HPLC analysis of vancomycin in group III was done to assess the concentration in DBM chips. Results: In group I, the infection persisted throughout the period of the study. Group II showed the fulminated infection at the grafted site with DBM chips sequestrating out. Vancomycin-impregnated decal chips in group III did not show any sign of infection and eventually incorporated. The bacterial load study showed a progressive load change and HPLC revealed an effective antibiotic concentration up to 3 weeks in both in vitro and in vivo. Conclusion: Decal bone chips were effective as the local antibiotic delivery vehicle in preventing the MRSA osteomyelitis model. It eluted vancomycin significantly and the graft uptake was also excellent

  2. Functionalized bimodal mesoporous silicas as carriers for controlled aspirin delivery

    International Nuclear Information System (INIS)

    Gao Lin; Sun Jihong; Li Yuzhen

    2011-01-01

    The bimodal mesoporous silica modified with 3-aminopropyltriethoxysilane was performed as the aspirin carrier. The samples' structure, drug loading and release profiles were characterized with X-ray diffraction, scanning electron microscopy, N 2 adsorption and desorption, Fourier transform infrared spectroscopy, TG analysis, elemental analysis and UV-spectrophotometer. For further exploring the effects of the bimodal mesopores on the drug delivery behavior, the unimodal mesoporous material MCM-41 was also modified as the aspirin carrier. Meantime, Korsmeyer-Peppas equation f t =kt n was employed to analyze the dissolution data in details. It is indicated that the bimodal mesopores are beneficial for unrestricted drug molecules diffusing and therefore lead to a higher loading and faster releasing than that of MCM-41. The results show that the aspirin delivery properties are influenced considerably by the mesoporous matrix, whereas the large pore of bimodal mesoporous silica is the key point for the improved controlled-release properties. - Graphical abstract: Loading (A) and release profiles (B) of aspirin in N-BMMs and N-MCM-41 indicated that BMMs have more drug loading capacity and faster release rate than that MCM-41. Highlights: → Bimodal mesoporous silicas (BMMs) and MCM-41 modified with amino group via post-treatment procedure. → Loading and release profiles of aspirin in modified BMMs and MCM-41. → Modified BMMs have more drug loading capacity and faster release rate than that modified MCM-41.

  3. Fibroblast-derived matrix (FDM) as a novel vascular endothelial growth factor delivery platform.

    Science.gov (United States)

    Du, Ping; Hwang, Mintai P; Noh, Yong Kwan; Subbiah, Ramesh; Kim, In Gul; Bae, Soon Eon; Park, Kwideok

    2014-11-28

    Vascular endothelial growth factor (VEGF) is one of the most important signaling cues during angiogenesis. Since many delivery systems of VEGF have been reported, the presentation of VEGF using a more physiologically relevant extracellular matrix (ECM), however, has yet to be thoroughly examined. In this study, we propose that fibroblast-derived extracellular matrix (FDM) is a novel platform for angiogenic growth factor delivery and that FDM-mediated VEGF delivery can result in an advanced angiogenic response. The FDMs, activated by EDC/NHS chemistry, were loaded with varying amounts of heparin. Different doses of VEGF were subsequently immobilized onto the heparin-grafted FDM (hep-FDM); 19.6 ± 0.6, 39.2 ± 3.2, and 54.8 ± 8.9 ng of VEGF were tethered using 100, 300, and 500 ng of initial VEGF, respectively. VEGF-tethered FDM was found chemoattractive and VEGF dose-dependent in triggering human umbilical vein endothelial cells (ECs) migration in vitro. When hep-FDM-bound VEGF (H-F/V) was encapsulated into alginate capsules (A/H-F/V) and subjected to release test for 28 days, it exhibited a significantly reduced burst release at early time point compared to that of A/V. The cell proliferation results indicated a substantially extended temporal effect of A/H-F/V on EC proliferation compared to those treated with soluble VEGF. For a further study, A/H-F/V was transplanted subcutaneously into ICR mice for up to 4 weeks to assess its in vivo effect on angiogenesis; VEGF delivered by hep-FDM was more competitive in promoting blood vessel ingrowth and maturation compared to other groups. Taken together, this study successfully engineered an FDM-mediated VEGF delivery system, documented its capacity to convey VEGF in a sustained manner, and demonstrated the positive effects of angiogenic activity in vivo as well as in vitro. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Attenuation of Colitis by Lactobacillus casei BL23 Is Dependent on the Dairy Delivery Matrix.

    Science.gov (United States)

    Lee, Bokyung; Yin, Xiaochen; Griffey, Stephen M; Marco, Maria L

    2015-09-01

    The role of the food delivery matrix in probiotic performance in the intestine is not well understood. Because probiotics are often provided to consumers in dairy products, we investigated the contributions of milk to the health-benefiting performance of Lactobacillus casei BL23 in a dextran sulfate sodium (DSS)-induced murine model of ulcerative colitis. L. casei BL23 protected against the development of colitis when ingested in milk but not in a nutrient-free buffer simulating consumption as a nutritional supplement. Consumption of (acidified) milk alone also provided some protection against weight loss and intestinal inflammation but was not as effective as L. casei and milk in combination. In contrast, L. casei mutants deficient in DltD (lipoteichoic acid d-alanine transfer protein) or RecA (recombinase A) were unable to protect against DSS-induced colitis, even when consumed in the presence of milk. Mice fed either L. casei or milk contained reduced quantities of colonic proinflammatory cytokines, indicating that the L. casei DltD(-) and RecA(-) mutants as well as L. casei BL23 in nutrient-free buffer were effective at modulating immune responses. However, there was not a direct correlation between colitis and quantities of these cytokines at the time of sacrifice. Identification of the cecal microbiota by 16S rRNA gene sequencing showed that L. casei in milk enriched for Comamonadaceae and Bifidobacteriaceae; however, the consumption of neither L. casei nor milk resulted in the restoration of the microbiota to resemble that of healthy animals. These findings strongly indicate that probiotic strain efficacy can be influenced by the food/supplement delivery matrix. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  5. Gold nanorods contained polyvinyl alcohol/chitosan nanofiber matrix for cell imaging and drug delivery

    International Nuclear Information System (INIS)

    Yan, Eryun; Cao, Minglu; Wang, Yuwei; Hao, Xiaoyuan; Pei, Shichun; Gao, Jianwei; Wang, Yan; Zhang, Zhuanfang; Zhang, Deqing

    2016-01-01

    Gold nanorods (AuNRs) that contained polyvinyl alcohol/chitosan (PVA/CS) hybrid nanofibers with dual functions are successfully fabricated by a simple electrospinning method. The results of transmission electron microscopy (TEM), X-ray diffraction (XRD) and energy dispersive X-ray (EDX) spectroscopy indicate that AuNRs are indeed encapsulated into the PVA/CS hybrid nanofibers. FTIR spectra results demonstrate that the chemical structures of PVA and CS are not affected when the AuNRs are introduced into the fibers. In vitro cytotoxicity test reveals that the hybrid fibers involving AuNRs are completely biocompatible. The as-prepared fibers can be used as a carrier for anticancer agent doxorubicin (DOX), and the drug is delivered into the cell nucleus. The AuNRs and DOX incorporated fibers are effective for inhibiting the growth and proliferation of ovary cancer cells and they can also be used as the cell imaging agent due to the unique optical properties of AuNRs. The nanofiber matrix combining two functions of cell imaging and drug delivery may be of great application potential in biomedical-related areas. - Highlights: • The AuNRs contained PVA/CS nanofibers are fabricated by electrospinning. • The hybrid fibers involving AuNRs are completely biocompatible. • The DOX loaded fibers are effective for inhibiting the proliferation of cancer cells. • The nanofibers combined two functions of cell imaging and drug delivery.

  6. Control-matrix approach to stellarator design and control

    International Nuclear Information System (INIS)

    Mynick, H.E.; Pomphrey, N.

    2000-01-01

    The full space Z always equal to {Zj=1,..Nz} of independent variables defining a stellarator configuration is large. To find attractive design points in this space, or to understand operational flexibility about a given design point, one needs insight into the topography in Z-space of the physics figures of merit Pi which characterize the machine performance, and means of determining those directions in Z-space which give one independent control over the Pi, as well as those which affect none of them, and so are available for design flexibility. The control matrix (CM) approach described here provides a mathematical means of obtaining these. In this work, the authors describe the CM approach and use it in studying some candidate Quasi-Axisymmetric (QA) stellarator configurations the NCSX design group has been considering. In the process of the analysis, a first exploration of the topography of the configuration space in the vicinity of these candidate systems has been performed, whose character is discussed

  7. Extracellular Matrix-Inspired Growth Factor Delivery Systems for Skin Wound Healing

    Energy Technology Data Exchange (ETDEWEB)

    Briquez, Priscilla S.; Hubbell, Jeffrey A.; Martino, Mikaël M.

    2015-08-01

    Blood vessel growth plays a key role in regenerative medicine, both to restore blood supply to ischemic tissues and to ensure rapid vascularization of clinical-size tissue-engineered grafts. For example, vascular endothelial growth factor (VEGF) is the master regulator of physiological blood vessel growth and is one of the main molecular targets of therapeutic angiogenesis approaches. However, angiogenesis is a complex process and there is a need to develop rational therapeutic strategies based on a firm understanding of basic vascular biology principles, as evidenced by the disappointing results of initial clinical trials of angiogenic factor delivery. In particular, the spatial localization of angiogenic signals in the extracellular matrix (ECM) is crucial to ensure the proper assembly and maturation of new vascular structures. Here, we discuss the therapeutic implications of matrix interactions of angiogenic factors, with a special emphasis on VEGF, as well as provide an overview of current approaches, based on protein and biomaterial engineering that mimic the regulatory functions of ECM to optimize the signaling microenvironment of vascular growth factors.

  8. Enhanced Controlled Transdermal Delivery of Torasemide Using ...

    African Journals Online (AJOL)

    To increase pore size and flexibility of the EVA matrix, plasticizers with citrate and phthalate groups were added to the matrix containing torasemide. To improve the ... The effects of the enhancers on the skin penetration were evaluated using Franz diffusion cell fitted with the intact excised rat skin. Results: Solubility and ...

  9. Financing and delivery mechanisms for mosquito control tools in ...

    African Journals Online (AJOL)

    Financing and delivery mechanisms for mosquito control tools in Sudan: A Strengths Weaknesses Opportunities and Threats (SWOT) analysis. ... However, it is not clear which options or mix of options present the most economically viable means in terms of financing and delivery, for malaria control. Methods: The study ...

  10. Controlled drug delivery systems towards new frontiers in patient care

    CERN Document Server

    Rossi, Filippo; Masi, Maurizio

    2016-01-01

    This book offers a state-of-the-art overview of controlled drug delivery systems, covering the most important innovative applications. The principles of controlled drug release and the mechanisms involved in controlled release are clearly explained. The various existing polymeric drug delivery systems are reviewed, and new frontiers in material design are examined in detail, covering a wide range of polymer modification techniques. The concluding chapter is a case study focusing on use of a drug-eluting stent. The book is designed to provide the reader with a complete understanding of the mechanisms and design of controlled drug delivery systems, and to this end includes numerous step-by-step tutorials. It illustrates how chemical engineers can advance medical care by designing polymeric delivery systems that achieve either temporal or spatial control of drug delivery and thus ensure more effective therapy that eliminates the potential for both under-and overdosing.

  11. Recent advances of controlled drug delivery using microfluidic platforms.

    Science.gov (United States)

    Sanjay, Sharma T; Zhou, Wan; Dou, Maowei; Tavakoli, Hamed; Ma, Lei; Xu, Feng; Li, XiuJun

    2017-09-15

    Conventional systematically-administered drugs distribute evenly throughout the body, get degraded and excreted rapidly while crossing many biological barriers, leaving minimum amounts of the drugs at pathological sites. Controlled drug delivery aims to deliver drugs to the target sites at desired rates and time, thus enhancing the drug efficacy, pharmacokinetics, and bioavailability while maintaining minimal side effects. Due to a number of unique advantages of the recent microfluidic lab-on-a-chip technology, microfluidic lab-on-a-chip has provided unprecedented opportunities for controlled drug delivery. Drugs can be efficiently delivered to the target sites at desired rates in a well-controlled manner by microfluidic platforms via integration, implantation, localization, automation, and precise control of various microdevice parameters. These features accordingly make reproducible, on-demand, and tunable drug delivery become feasible. On-demand self-tuning dynamic drug delivery systems have shown great potential for personalized drug delivery. This review presents an overview of recent advances in controlled drug delivery using microfluidic platforms. The review first briefly introduces microfabrication techniques of microfluidic platforms, followed by detailed descriptions of numerous microfluidic drug delivery systems that have significantly advanced the field of controlled drug delivery. Those microfluidic systems can be separated into four major categories, namely drug carrier-free micro-reservoir-based drug delivery systems, highly integrated carrier-free microfluidic lab-on-a-chip systems, drug carrier-integrated microfluidic systems, and microneedles. Microneedles can be further categorized into five different types, i.e. solid, porous, hollow, coated, and biodegradable microneedles, for controlled transdermal drug delivery. At the end, we discuss current limitations and future prospects of microfluidic platforms for controlled drug delivery. Copyright

  12. Direct Torque Control of Matrix Converter Fed Induction Motor Drive

    Directory of Open Access Journals (Sweden)

    JAGADEESAN Karpagam

    2011-10-01

    Full Text Available This paper presents the Direct TorqueControl (DTC of induction motor drive using matrixconverters. DTC is a high performance motor controlscheme with fast torque and flux responses. However,the main disadvantage of conventional DTC iselectromagnetic torque ripple. In this paper, directtorque control for Induction Motors using MatrixConverters is analysed and points out the problem ofthe electromagnetic torque ripple which is one of themost important drawbacks of the Direct TorqueControl. Besides, the matrix converter is a single-stageac-ac power conversion device without dc-link energystorage elements. Matrix converter (MC may becomea good alternative to voltage-source inverter (VSI.This work combines the advantages of the matrixconverter with those of the DTC technique, generatingthe required voltage vectors under unity input powerfactor operation. Simulation results demonstrates theeffectiveness of the torque control.

  13. Controlled Delivery of Vancomycin via Charged Hydrogels

    Science.gov (United States)

    Gustafson, Carl T.; Boakye-Agyeman, Felix; Brinkman, Cassandra L.; Reid, Joel M.; Patel, Robin; Bajzer, Zeljko; Dadsetan, Mahrokh; Yaszemski, Michael J.

    2016-01-01

    Surgical site infection (SSI) remains a significant risk for any clean orthopedic surgical procedure. Complications resulting from an SSI often require a second surgery and lengthen patient recovery time. The efficacy of antimicrobial agents delivered to combat SSI is diminished by systemic toxicity, bacterial resistance, and patient compliance to dosing schedules. We submit that development of localized, controlled release formulations for antimicrobial compounds would improve the effectiveness of prophylactic surgical wound antibiotic treatment while decreasing systemic side effects. Our research group developed and characterized oligo(poly(ethylene glycol)fumarate) / sodium methacrylate (OPF/SMA) charged copolymers as biocompatible hydrogel matrices. Here, we report the engineering of this copolymer for use as an antibiotic delivery vehicle in surgical applications. We demonstrate that these hydrogels can be efficiently loaded with vancomycin (over 500 μg drug per mg hydrogel) and this loading mechanism is both time- and charge-dependent. Vancomycin release kinetics are shown to be dependent on copolymer negative charge. In the first 6 hours, we achieved as low as 33.7% release. In the first 24 hours, under 80% of total loaded drug was released. Further, vancomycin release from this system can be extended past four days. Finally, we show that the antimicrobial activity of released vancomycin is equivalent to stock vancomycin in inhibiting the growth of colonies of a clinically derived strain of methicillin-resistant Staphylococcus aureus. In summary, our work demonstrates that OPF/SMA hydrogels are appropriate candidates to deliver local antibiotic therapy for prophylaxis of surgical site infection. PMID:26760034

  14. Controlled Delivery of Vancomycin via Charged Hydrogels.

    Directory of Open Access Journals (Sweden)

    Carl T Gustafson

    Full Text Available Surgical site infection (SSI remains a significant risk for any clean orthopedic surgical procedure. Complications resulting from an SSI often require a second surgery and lengthen patient recovery time. The efficacy of antimicrobial agents delivered to combat SSI is diminished by systemic toxicity, bacterial resistance, and patient compliance to dosing schedules. We submit that development of localized, controlled release formulations for antimicrobial compounds would improve the effectiveness of prophylactic surgical wound antibiotic treatment while decreasing systemic side effects. Our research group developed and characterized oligo(poly(ethylene glycolfumarate/sodium methacrylate (OPF/SMA charged copolymers as biocompatible hydrogel matrices. Here, we report the engineering of this copolymer for use as an antibiotic delivery vehicle in surgical applications. We demonstrate that these hydrogels can be efficiently loaded with vancomycin (over 500 μg drug per mg hydrogel and this loading mechanism is both time- and charge-dependent. Vancomycin release kinetics are shown to be dependent on copolymer negative charge. In the first 6 hours, we achieved as low as 33.7% release. In the first 24 hours, under 80% of total loaded drug was released. Further, vancomycin release from this system can be extended past four days. Finally, we show that the antimicrobial activity of released vancomycin is equivalent to stock vancomycin in inhibiting the growth of colonies of a clinically derived strain of methicillin-resistant Staphylococcus aureus. In summary, our work demonstrates that OPF/SMA hydrogels are appropriate candidates to deliver local antibiotic therapy for prophylaxis of surgical site infection.

  15. Multiparticulate Drug Delivery Systems for Controlled Release | Dey ...

    African Journals Online (AJOL)

    Pharmaceutical invention and research are increasingly focusing on delivery systems which enhance desirable therapeutic objectives while minimising side effects. Recent trends indicate that multiparticulate drug delivery systems are especially suitable for achieving controlled or delayed release oral formulations with low ...

  16. A difference-matrix metaheuristic for intensity map segmentation in step-and-shoot IMRT delivery.

    Science.gov (United States)

    Gunawardena, Athula D A; D'Souza, Warren D; Goadrich, Laura D; Meyer, Robert R; Sorensen, Kelly J; Naqvi, Shahid A; Shi, Leyuan

    2006-05-21

    At an intermediate stage of radiation treatment planning for IMRT, most commercial treatment planning systems for IMRT generate intensity maps that describe the grid of beamlet intensities for each beam angle. Intensity map segmentation of the matrix of individual beamlet intensities into a set of MLC apertures and corresponding intensities is then required in order to produce an actual radiation delivery plan for clinical use. Mathematically, this is a very difficult combinatorial optimization problem, especially when mechanical limitations of the MLC lead to many constraints on aperture shape, and setup times for apertures make the number of apertures an important factor in overall treatment time. We have developed, implemented and tested on clinical cases a metaheuristic (that is, a method that provides a framework to guide the repeated application of another heuristic) that efficiently generates very high-quality (low aperture number) segmentations. Our computational results demonstrate that the number of beam apertures and monitor units in the treatment plans resulting from our approach is significantly smaller than the corresponding values for treatment plans generated by the heuristics embedded in a widely use commercial system. We also contrast the excellent results of our fast and robust metaheuristic with results from an 'exact' method, branch-and-cut, which attempts to construct optimal solutions, but, within clinically acceptable time limits, generally fails to produce good solutions, especially for intensity maps with more than five intensity levels. Finally, we show that in no instance is there a clinically significant change of quality associated with our more efficient plans.

  17. A difference-matrix metaheuristic for intensity map segmentation in step-and-shoot IMRT delivery

    International Nuclear Information System (INIS)

    Gunawardena, Athula D A; D'Souza, Warren D; Goadrich, Laura D; Meyer, Robert R; Sorensen, Kelly J; Naqvi, Shahid A; Shi, Leyuan

    2006-01-01

    At an intermediate stage of radiation treatment planning for IMRT, most commercial treatment planning systems for IMRT generate intensity maps that describe the grid of beamlet intensities for each beam angle. Intensity map segmentation of the matrix of individual beamlet intensities into a set of MLC apertures and corresponding intensities is then required in order to produce an actual radiation delivery plan for clinical use. Mathematically, this is a very difficult combinatorial optimization problem, especially when mechanical limitations of the MLC lead to many constraints on aperture shape, and setup times for apertures make the number of apertures an important factor in overall treatment time. We have developed, implemented and tested on clinical cases a metaheuristic (that is, a method that provides a framework to guide the repeated application of another heuristic) that efficiently generates very high-quality (low aperture number) segmentations. Our computational results demonstrate that the number of beam apertures and monitor units in the treatment plans resulting from our approach is significantly smaller than the corresponding values for treatment plans generated by the heuristics embedded in a widely use commercial system. We also contrast the excellent results of our fast and robust metaheuristic with results from an 'exact' method, branch-and-cut, which attempts to construct optimal solutions, but, within clinically acceptable time limits, generally fails to produce good solutions, especially for intensity maps with more than five intensity levels. Finally, we show that in no instance is there a clinically significant change of quality associated with our more efficient plans

  18. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    Science.gov (United States)

    2017-08-01

    AFRL-SA-WP-SR-2017-0024 Closed Loop Control of Oxygen Delivery and Oxygen Generation Dr. Jay Johannigman1, Richard Branson1...for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO...TITLE AND SUBTITLE Closed Loop Control of Oxygen Delivery and Oxygen Generation 5a. CONTRACT NUMBER FA8650-10-2-6140 5b. GRANT NUMBER

  19. Biocompatible polymeric implants for controlled drug delivery produced by MAPLE

    Science.gov (United States)

    Paun, Irina Alexandra; Moldovan, Antoniu; Luculescu, Catalin Romeo; Dinescu, Maria

    2011-10-01

    Implants consisting of drug cores coated with polymeric films were developed for delivering drugs in a controlled manner. The polymeric films were produced using matrix assisted pulsed laser evaporation (MAPLE) and consist of poly(lactide-co-glycolide) (PLGA), used individually as well as blended with polyethylene glycol (PEG). Indomethacin (INC) was used as model drug. The implants were tested in vitro (i.e. in conditions similar with those encountered inside the body), for predicting their behavior after implantation at the site of action. To this end, they were immersed in physiological media (i.e. phosphate buffered saline PBS pH 7.4 and blood). At various intervals of PBS immersion (and respectively in blood), the polymeric films coating the drug cores were studied in terms of morphology, chemistry, wettability and blood compatibility. PEG:PLGA film exhibited superior properties as compared to PLGA film, the corresponding implant being thus more suitable for internal use in the human body. In addition, the implant containing PEG:PLGA film provided an efficient and sustained release of the drug. The kinetics of the drug release was consistent with a diffusion mediated mechanism (as revealed by fitting the data with Higuchi's model); the drug was gradually released through the pores formed during PBS immersion. In contrast, the implant containing PLGA film showed poor drug delivery rates and mechanical failure. In this case, fitting the data with Hixson-Crowell model indicated a release mechanism dominated by polymer erosion.

  20. Characterization and control of the fiber-matrix interface in ceramic matrix composites

    Energy Technology Data Exchange (ETDEWEB)

    Lowden, R.A.

    1989-03-01

    Fiber-reinforced SiC composites fabricated by thermal-gradient forced-flow chemical-vapor infiltration (FCVI) have exhibited both composite (toughened) and brittle behavior during mechanical property evaluation. Detailed analysis of the fiber-matrix interface revealed that a silica layer on the surface of Nicalon Si-C-O fibers tightly bonds the fiber to the matrix. The strongly bonded fiber and matrix, combined with the reduction in the strength of the fibers that occurs during processing, resulted in the observed brittle behavior. The mechanical behavior of Nicalon/SiC composites has been improved by applying thin coatings (silicon carbide, boron, boron nitride, molybdenum, carbon) to the fibers, prior to densification, to control the interfacial bond. Varying degrees of bonding have been achieved with different coating materials and film thicknesses. Fiber-matrix bond strengths have been quantitatively evaluated using an indentation method and a simple tensile test. The effects of bonding and friction on the mechanical behavior of this composite system have been investigated. 167 refs., 59 figs., 18 tabs.

  1. The impact of treatment complexity and computer-control delivery technology on treatment delivery errors

    International Nuclear Information System (INIS)

    Fraass, Benedick A.; Lash, Kathy L.; Matrone, Gwynne M.; Volkman, Susan K.; McShan, Daniel L.; Kessler, Marc L.; Lichter, Allen S.

    1998-01-01

    Purpose: To analyze treatment delivery errors for three-dimensional (3D) conformal therapy performed at various levels of treatment delivery automation and complexity, ranging from manual field setup to virtually complete computer-controlled treatment delivery using a computer-controlled conformal radiotherapy system (CCRS). Methods and Materials: All treatment delivery errors which occurred in our department during a 15-month period were analyzed. Approximately 34,000 treatment sessions (114,000 individual treatment segments [ports]) on four treatment machines were studied. All treatment delivery errors logged by treatment therapists or quality assurance reviews (152 in all) were analyzed. Machines 'M1' and 'M2' were operated in a standard manual setup mode, with no record and verify system (R/V). MLC machines 'M3' and 'M4' treated patients under the control of the CCRS system, which (1) downloads the treatment delivery plan from the planning system; (2) performs some (or all) of the machine set up and treatment delivery for each field; (3) monitors treatment delivery; (4) records all treatment parameters; and (5) notes exceptions to the electronically-prescribed plan. Complete external computer control is not available on M3; therefore, it uses as many CCRS features as possible, while M4 operates completely under CCRS control and performs semi-automated and automated multi-segment intensity modulated treatments. Analysis of treatment complexity was based on numbers of fields, individual segments, nonaxial and noncoplanar plans, multisegment intensity modulation, and pseudoisocentric treatments studied for a 6-month period (505 patients) concurrent with the period in which the delivery errors were obtained. Treatment delivery time was obtained from the computerized scheduling system (for manual treatments) or from CCRS system logs. Treatment therapists rotate among the machines; therefore, this analysis does not depend on fixed therapist staff on particular

  2. Microprocessor Based Temperature Control of Liquid Delivery with Flow Disturbances.

    Science.gov (United States)

    Kaya, Azmi

    1982-01-01

    Discusses analytical design and experimental verification of a PID control value for a temperature controlled liquid delivery system, demonstrating that the analytical design techniques can be experimentally verified by using digital controls as a tool. Digital control instrumentation and implementation are also demonstrated and documented for…

  3. Measurement of the time-resolved reflection matrix for enhancing light energy delivery into a scattering medium.

    Science.gov (United States)

    Choi, Youngwoon; Hillman, Timothy R; Choi, Wonjun; Lue, Niyom; Dasari, Ramachandra R; So, Peter T C; Choi, Wonshik; Yaqoob, Zahid

    2013-12-13

    Multiple scatterings occurring in a turbid medium attenuate the intensity of propagating waves. Here, we propose a method to efficiently deliver light energy to the desired target depth in a scattering medium. We measure the time-resolved reflection matrix of a scattering medium using coherent time-gated detection. From this matrix, we derive and experimentally implement an incident wave pattern that optimizes the detected signal corresponding to a specific arrival time. This leads to enhanced light delivery at the target depth. The proposed method will lay a foundation for efficient phototherapy and deep-tissue in vivo imaging in the near future.

  4. Reduction of treatment delivery variances with a computer-controlled treatment delivery system

    International Nuclear Information System (INIS)

    Fraass, B.A.; Lash, K.L.; Matrone, G.M.; Lichter, A.S.

    1997-01-01

    Purpose: To analyze treatment delivery variances for 3-D conformal therapy performed at various levels of treatment delivery automation, ranging from manual field setup to virtually complete computer-controlled treatment delivery using a computer-controlled conformal radiotherapy system. Materials and Methods: All external beam treatments performed in our department during six months of 1996 were analyzed to study treatment delivery variances versus treatment complexity. Treatments for 505 patients (40,641 individual treatment ports) on four treatment machines were studied. All treatment variances noted by treatment therapists or quality assurance reviews (39 in all) were analyzed. Machines 'M1' (CLinac (6(100))) and 'M2' (CLinac 1800) were operated in a standard manual setup mode, with no record and verify system (R/V). Machines 'M3' (CLinac 2100CD/MLC) and ''M4'' (MM50 racetrack microtron system with MLC) treated patients under the control of a computer-controlled conformal radiotherapy system (CCRS) which 1) downloads the treatment delivery plan from the planning system, 2) performs some (or all) of the machine set-up and treatment delivery for each field, 3) monitors treatment delivery, 4) records all treatment parameters, and 5) notes exceptions to the electronically-prescribed plan. Complete external computer control is not available on M3, so it uses as many CCRS features as possible, while M4 operates completely under CCRS control and performs semi-automated and automated multi-segment intensity modulated treatments. Analysis of treatment complexity was based on numbers of fields, individual segments (ports), non-axial and non-coplanar plans, multi-segment intensity modulation, and pseudo-isocentric treatments (and other plans with computer-controlled table motions). Treatment delivery time was obtained from the computerized scheduling system (for manual treatments) or from CCRS system logs. Treatment therapists rotate among the machines, so this analysis

  5. Compressor Surge Control Design Using Linear Matrix Inequality Approach

    OpenAIRE

    Uddin, Nur; Gravdahl, Jan Tommy

    2017-01-01

    A novel design for active compressor surge control system (ASCS) using linear matrix inequality (LMI) approach is presented and including a case study on piston-actuated active compressor surge control system (PAASCS). The non-linear system dynamics of the PAASCS is transformed into linear parameter varying (LPV) system dynamics. The system parameters are varying as a function of the compressor performance curve slope. A compressor surge stabilization problem is then formulated as a LMI probl...

  6. Evaluation of olibanum and its resin as rate controlling matrix for controlled release of diclofenac

    OpenAIRE

    Chowdary KPR; Mohapatra P; Murali Krishna M

    2006-01-01

    Olibanum and its resin and carbohydrate fractions were evaluated as rate controlling matrix materials in tablets for controlled release of diclofenac. Diclofenac matrix tablets were formulated employing olibanum and its resin and carbohydrate fractions in different concentrations and the tablets were evaluated for various tablet characters including drug release kinetics and mechanism. Olibanum and its resin component exhibited excellent retarding effect on drug release from the matrix tablet...

  7. A difference-matrix metaheuristic for intensity map segmentation in step-and-shoot IMRT delivery

    Energy Technology Data Exchange (ETDEWEB)

    Gunawardena, Athula D A [Department of Mathematics and Computer Sciences, University of Wisconsin-Whitewater, 800 West Main Street, Whitewater, WI (United States); D' Souza, Warren D [Department of Radiation Oncology, School of Medicine, University of Maryland, 22 South Greene Street, Baltimore, MD (United States); Goadrich, Laura D [Department of Industrial and Systems Engineering, University of Wisconsin-Madison, Madison, WI (United States); Meyer, Robert R [Department of Computer Sciences, University of Wisconsin-Madison, Madison, WI (United States); Sorensen, Kelly J [Department of Computer Sciences, University of Wisconsin-Madison, Madison, WI (United States); Naqvi, Shahid A [Department of Radiation Oncology, School of Medicine, University of Maryland, 22 South Greene Street, Baltimore, MD (United States); Shi, Leyuan [Department of Industrial and Systems Engineering, University of Wisconsin-Madison, Madison, WI (United States)

    2006-05-21

    At an intermediate stage of radiation treatment planning for IMRT, most commercial treatment planning systems for IMRT generate intensity maps that describe the grid of beamlet intensities for each beam angle. Intensity map segmentation of the matrix of individual beamlet intensities into a set of MLC apertures and corresponding intensities is then required in order to produce an actual radiation delivery plan for clinical use. Mathematically, this is a very difficult combinatorial optimization problem, especially when mechanical limitations of the MLC lead to many constraints on aperture shape, and setup times for apertures make the number of apertures an important factor in overall treatment time. We have developed, implemented and tested on clinical cases a metaheuristic (that is, a method that provides a framework to guide the repeated application of another heuristic) that efficiently generates very high-quality (low aperture number) segmentations. Our computational results demonstrate that the number of beam apertures and monitor units in the treatment plans resulting from our approach is significantly smaller than the corresponding values for treatment plans generated by the heuristics embedded in a widely use commercial system. We also contrast the excellent results of our fast and robust metaheuristic with results from an 'exact' method, branch-and-cut, which attempts to construct optimal solutions, but, within clinically acceptable time limits, generally fails to produce good solutions, especially for intensity maps with more than five intensity levels. Finally, we show that in no instance is there a clinically significant change of quality associated with our more efficient plans.

  8. Application of the matrix converter to power flow control

    Directory of Open Access Journals (Sweden)

    Szcześniak P.

    2014-09-01

    Full Text Available Advanced power electronic converters can provide the means to control power flow and ensure proper and secure operation of the future power grid. The small electrical energy sources dispersed in electrical power systems referred to as distributed generation are one of the most significant parts of future grids - Smart Grids. The threephase, direct matrix converter is an alternative solution to the conventional AC-DC-AC converter for interfacing two AC systems in distributed power generation with different voltage and/or frequency parameters. This paper presents a control analysis of a threephase matrix converter employed as a power interface of future electrical grids. The proposed system has been successfully tested for bidirectional power flow operation with different grid operating conditions, such as, frequency and voltage variation

  9. Investigation of Degradation Properties of Poly(lactide-co-glycolide) Matrix for Anticancer Agent Delivery

    International Nuclear Information System (INIS)

    Ghani, S. M.; Mohamed, M. S. W.; Yahya, A. F.; Noorsal, K.

    2010-01-01

    Poly(lactide-co-glycolide)(PLA 50 GA 50 ) is a biodegradable and biocompatible polymer. It offers tremendous potential as a basis for drug delivery, either as drug delivery system alone or in conjugate with a medical device. The PLA 50 GA 50 is the material of choice for relatively shorter-duration applications, while the homopolymer PLA (poly-L-lactide) and PGA (polyglycolide) are preferred for longer term delivery of drugs. This paper discusses the degradation properties of poly(lactide-co-glycolide)(PLA 50 GA 50 ) at inherent viscosity of 0.89 dL/g as preliminary studies for anticancer agent delivery.

  10. Balancing Cell Migration with Matrix Degradation Enhances Gene Delivery to Cells Cultured Three-Dimensionally Within Hydrogels

    Science.gov (United States)

    Shepard, Jaclyn A.; Huang, Alyssa; Shikanova, Ariella; Shea, Lonnie D.

    2010-01-01

    In regenerative medicine, hydrogels are employed to fill defects and support the infiltration of cells that can ultimately regenerate tissue. Gene delivery within hydrogels targeting infiltrating cells has the potential to promote tissue formation, but the delivery efficiency of nonviral vectors within hydrogels is low hindering their applicability in tissue regeneration. To improve their functionality, we have conducted a mechanistic study to investigate the contribution of cell migration and matrix degradation on gene delivery. In this report, lipoplexes were entrapped within hydrogels based on poly(ethylene glycol) (PEG) crosslinked with peptides containing matrix metalloproteinase degradable sequences. The mesh size of these hydrogels is substantially less than the size of the entrapped lipoplexes, which can function to retain vectors. Cell migration and transfection were simultaneously measured within hydrogels with varying density of cell adhesion sites (Arg-Gly-Asp peptides) and solids content. Increasing RGD density increased expression levels up to 100-fold, while greater solids content sustained expression levels for 16 days. Increasing RGD density and decreasing solids content increased cell migration, which indicates expression levels increase with increased cell migration. Initially exposing cells to vector resulted in transient expression that declined after 2 days, verifying the requirement of migration to sustain expression. Transfected cells were predominantly located within the population of migrating cells for hydrogels that supported cell migration. Although the small mesh size retained at least 70% of the lipoplexes in the absence of cells after 32 days, the presence of cells decreased retention to 10% after 16 days. These results indicate that vectors retained within hydrogels contact migrating cells, and that persistent cell migration can maintain elevated expression levels. Thus matrix degradation and cell migration are fundamental design

  11. Progress in Controlled Gastroretentive Delivery Systems | Garg ...

    African Journals Online (AJOL)

    The purpose of this paper is to review the recent literature and current technology used in the development of gastroretentive dosage forms. Keywords: Gastroretention, Oral controlled release, Swelling, Narrow absorption window, Floating dosage form. Tropical Journal of Pharmaceutical Research Vol. 7 (3) 2008: pp. 1055- ...

  12. Monolithic Controlled Delivery Systems: Part I. Basic Characteristics and Mechanisms

    Directory of Open Access Journals (Sweden)

    Rumiana Blagoeva

    2006-04-01

    Full Text Available The article considers contemporary systems for controlled delivery of active agents, such as drugs, agricultural chemicals, pollutants and additives in the environment. A useful classification of the available controlled release systems (CRS is proposed according to the type of control (passive, active or self-preprogrammed and according to the main controlling mechanism (diffusion, swelling, dissolution or erosion. Special attention is given to some of the most used CRS - polymer monoliths. The structural and physical-chemical characteristics of CRS as well as the basic approaches to their production are examined. The basic mechanisms of controlled agent release are reviewed in detail and factors influencing the release kinetics are classified according to their importance. The present study can be helpful for understanding and applying the available mathematical models and for developing more comprehensive ones intended for design of new controlled delivery systems.

  13. TECHNOLOGY AND ANALYSIS DEVELOPMENT OF STOMATOLOGICAL MATRIX SYSTEM OF MULTIFUNCTIONAL ACTION DELIVERY

    Directory of Open Access Journals (Sweden)

    T. F. Marinina

    2014-01-01

    Full Text Available Timeliness of double-layer matrix system (of stomatological medicated films with antiinflammatory, local anesthetic, regenerative, anti-edematous action was shown. One layer of the system includes lidocaine hydrochloride and kalanchoe sap, another contains furacilin and urea. The best possible polymer carriers of preparations under study which provide their sufficient release from matrix system. Signified antimicrobic activity of double-layer system and osmotic activity were established. Double-layer matrix systems offered may be used in stomatology with for treatment and preventive measures of different diseases of parodontium tissues

  14. Configuration control based on risk matrix for radiotherapy treatment

    International Nuclear Information System (INIS)

    Montes de Oca Quinnones, Joe; Torres Valle, Antonio

    2015-01-01

    The incorporation of the science and technique breakthroughs in the application of the radiotherapy represents a challenge so that, the appearance of equipment failure or human mistakes that triggers unfavorable consequences for patients, public, or the occupationally exposed workers; it is also diversified forcing to incorporate besides, as part of the efforts, new techniques for the evaluation of risk and the detection of the weak points that can lead to these consequences. In order to evaluate the risks of the radiotherapy practices there is the SEVRRA code, based on the method of Risk Matrix. The system SEVRRA is the most frequently used code in the applications of risk studies in radiotherapy treatment. On the other hand, starting from the development of tools to control the dangerous configurations in nuclear power plants, it has been developed the SECURE code, which in its application variant of Risk Matrix, has gain a comfortable interface man-machine to make risk analyses to the radiotherapy treatment, molding in this way a lot of combinations of scenarios. These capacities outstandingly facilitate the studies and risk optimization applications in these practices. In the system SECURE-Risk Matrix are incorporated graphic and analytical capacities, which make more flexible the analyses and the subsequent documentation of all the results. The paper shows the the application of the proposed system to an integral risk study for the process of radiotherapy treatment with linear accelerator. (Author)

  15. Electrosprayed nanoparticle delivery system for controlled release

    Energy Technology Data Exchange (ETDEWEB)

    Eltayeb, Megdi, E-mail: megdi.eltayeb@sustech.edu [Department of Biomedical Engineering, Sudan University of Science and Technology, PO Box 407, Khartoum (Sudan); Stride, Eleanor, E-mail: eleanor.stride@eng.ox.ac.uk [Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Headington OX3 7DQ (United Kingdom); Edirisinghe, Mohan, E-mail: m.edirisinghe@ucl.ac.uk [Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE (United Kingdom); Harker, Anthony, E-mail: a.harker@ucl.ac.uk [London Centre for Nanotechnology, Gordon Street, London WC1H 0AH (United Kingdom); Department of Physics & Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    2016-09-01

    This study utilises an electrohydrodynamic technique to prepare core-shell lipid nanoparticles with a tunable size and high active ingredient loading capacity, encapsulation efficiency and controlled release. Using stearic acid and ethylvanillin as model shell and active ingredients respectively, we identify the processing conditions and ratios of lipid:ethylvanillin required to form nanoparticles. Nanoparticles with a mean size ranging from 60 to 70 nm at the rate of 1.37 × 10{sup 9} nanoparticles per minute were prepared with different lipid:ethylvanillin ratios. The polydispersity index was ≈ 21% and the encapsulation efficiency ≈ 70%. It was found that the rate of ethylvanillin release was a function of the nanoparticle size, and lipid:ethylvanillin ratio. The internal structure of the lipid nanoparticles was studied by transmission electron microscopy which confirmed that the ethylvanillin was encapsulated within a stearic acid shell. Fourier transform infrared spectroscopy analysis indicated that the ethylvanillin had not been affected. Extensive analysis of the release of ethylvanillin was performed using several existing models and a new diffusive release model incorporating a tanh function. The results were consistent with a core-shell structure. - Highlights: • Electrohydrodynamic spraying is used to produce lipid-coated nanoparticles. • A new model is proposed for the release rates of active components from nanoparticles. • The technique has potential applications in food science and medicine. • Electrohydrodynamic processing controlled release lipid nanoparticles.

  16. A DSP controlled one-to-three phase matrix converter

    Energy Technology Data Exchange (ETDEWEB)

    Dubovsky, J.; Dobrucly, B; Tabacek, R.; Havrila, R. [Department of Electric Traction and Energetics Faculty of Electrical Engineering, University of Zilina (Slovakia)

    1997-12-31

    This paper deals with the theoretical analysis computer simulation and experimental results of IM fed by a one-to-three phase matrix converter which offers a unique solution for single phase electric traction applications. The proposed drive in comparison with currently used conventional drives reduces the number of power switching elements of the converter, which increases drives dependability and brings lower investment in power electronics used in drive. Further advantage is that the converter is controlled with nearly unity power factor which cuts down the operational expenses and offers higher overall performance of the drive. (orig.) 6 refs.

  17. Matrix converter controlled with the direct transfer function approach

    DEFF Research Database (Denmark)

    Rodriguez, J.; Silva, E.; Blaabjerg, Frede

    2005-01-01

    Power electronics is an emerging technology. New power circuits are invented and have to be introduced into the power electronics curriculum. One of the interesting new circuits is the matrix converter (MC), and this paper analyses its working principles. A simple model is proposed to represent...... the power circuit, including the input filter. The power semiconductors are modelled as ideal bidirectional switches and the MC is controlled using a direct transfer function approach. The modulation strategy of the converter is explained in a complete and clear form. The commutation problem of two switches...

  18. Formulation and Evaluation of Olanzapine Matrix Pellets for Controlled Release

    Directory of Open Access Journals (Sweden)

    S Mohammed Khan

    2011-10-01

    Full Text Available "nBackground and the purpose of the study: Olanzapine is an antipsychotic used in treatment of schizophrenia. This research was carried out to design oral controlled release matrix pellets of water insoluble drug Olanzapine (OZ, using blend of Sodium Alginate (SA and Glyceryl Palmito-Stearate (GPS as matrix polymers, micro crystalline cellulose (MCC as spheronizer enhancer and Sodium Lauryl Sulphate (SLS as pore forming agent. Olanzapine is an antipsychotic used in treatment of   schizophrenia. This research was carried out to design oral controlled release matrix pellets of water insoluble drug Olanzapine (OZ, using blend of Sodium Alginate (SA and Glyceryl Palmito-Stearate (GPS as matrix polymers, micro crystalline cellulose (MCC as spheronizer enhancer and Sodium Lauryl Sulphate (SLS as pore forming agent. "nMethods: OZ formulations were developed by the pelletization technique by drug loaded pellets and characterized with regard to the drug content, size distribution, Scanning Electron Microscopy (SEM, Differential Scanning Calorimetry (DSC, Fourier Transform Infrared Spectroscopy (FTIR and X-ray Diffraction study (XRD. Stability studies were carried out on the optimized formulation for a period of 90 days at 40 ± 2 °C and 75 ± 5% relative humidity. Results and major conclusion: The drug content was in the range of 93.34-98.12 %. The mean particle size of the drug loaded pellets was in the range 1024 to 1087μm. SEM photographs and calculated sphericity factor confirmed that the prepared formulations were spherical in nature. The compatibility between drug and polymers in the drug loaded pellets was confirmed by DSC and FTIR studies. Stability studies indicated that pellets are stable. XRD patterns revealed the crystalline nature of the pure OZ. Loose surface crystal study indicated that crystalline OZ is present in all formulations and more clear in formulation F5. Drug release was controlled for more than 24 hrs and mechanism of the

  19. Total matrix metalloproteinase-8 serum levels in patients labouring preterm and patients with threatened preterm delivery.

    Directory of Open Access Journals (Sweden)

    Piotr Laudański

    2010-11-01

    Full Text Available Preterm labour and prematurity are still a main cause of perinatal morbidity nowadays. The aim of our study was to assess the role of MMP-8 as a predictive marker of preterm delivery. Four groups of patients were involved to the study: I - pregnant women at 24-34 weeks of gestation with any symptoms of threatened preterm labour; II - threatened preterm labour patients between 24-34 weeks of gestation; III - preterm vaginal delivery patients; IV - healthy term vaginal delivery patients. Serum concentration of total MMP-8 was measured using two enzyme-linked immunosorbent assays. There were no significant differences in the median concentrations of total MMP-8 between physiological pregnancy and threatened preterm labour patients with existing uterine contractility. No significant differences of total MMP-8 were either found between healthy term and preterm labouring patients. The studies on a larger population are needed to reject the hypothesis that preterm labour is connected with increased MMP-8 plasma concentrations of women in preterm labour and threatened preterm delivery.

  20. Analyzing polymeric matrix for fabrication of a biodegradable microneedle array to enhance transdermal delivery.

    Science.gov (United States)

    Hwa, Kuo-Yuan; Chang, Vincent H S; Cheng, Yao-Yi; Wang, Yue-Da; Jan, Pey-Shynan; Subramani, Boopathi; Wu, Min-Ju; Wang, Bo-Kai

    2017-09-19

    Traditional drug delivery systems, using invasive, transdermal, and oral routes, are limited by various factors, such as the digestive system environment, skin protection, and sensory nerve stimulation. To improve the drug delivery system, we fabricated a polysaccharide-based, dissolvable microneedle-based array, which combines the advantages of both invasive and transdermal delivery systems, and promises to be an innovative solution for minimally invasive drug delivery. In this study, we designed a reusable aluminum mold that greatly improved the efficiency and convenience of microneedle fabrication. Physical characterization of the polysaccharides, individual or mixed at different ratios, was performed to identify a suitable molecule to fabricate the dissolvable microneedle. We used a vacuum deposition-based micro-molding method at low temperature to fabricate the model. Using a series of checkpoints from material into product, a systematic feedback mechanism was built into the "all-in-one" fabrication step, which helped to improve production yields. The physical properties of the fabricated microneedle were assessed. The cytotoxicity analysis and animal testing of the microneedle demonstrated the safety and compatibility of the microneedle, and the successful penetration and effective release of a model protein.

  1. Functionalized mesoporous silica materials for controlled drug delivery.

    Science.gov (United States)

    Yang, Piaoping; Gai, Shili; Lin, Jun

    2012-05-07

    In the past decade, non-invasive and biocompatible mesoporous silica materials as efficient drug delivery systems have attracted special attention. Great progress in structure control and functionalization (magnetism and luminescence) design has been achieved for biotechnological and biomedical applications. This review highlights the most recent research progress on silica-based controlled drug delivery systems, including: (i) pure mesoporous silica sustained-release systems, (ii) magnetism and/or luminescence functionalized mesoporous silica systems which integrate targeting and tracking abilities of drug molecules, and (iii) stimuli-responsive controlled release systems which are able to respond to environmental changes, such as pH, redox potential, temperature, photoirradiation, and biomolecules. Although encouraging and potential developments have been achieved, design and mass production of novel multifunctional carriers, some practical biological application, such as biodistribution, the acute and chronic toxicities, long-term stability, circulation properties and targeting efficacy in vivo are still challenging. This journal is © The Royal Society of Chemistry 2012

  2. Direct Torque Control of Induction Motor with Matrix Converter

    Directory of Open Access Journals (Sweden)

    Khalaf Salloum Gaeid

    2016-05-01

    Full Text Available The matrix converter (MC with direct torque control (DTC combination is efficient way to get better performance specifications in the industry. The MC and the DTC advantages are combined together. The reduction of complexity and cost of DC link in the DTC since it has no capacitors in the circuit. However, the controlling torque is a big problem it in DTC because of high ripple torque production which results in vibrations response in the operation of the iductuction motor as it has no PID to control the torque directly. To overcome this, a combination of MC with DTC is applied to reduce the fluctuation in the output torque and minimize the steady state error. This paper presents the simulation analysis of induction machine drives using Maltlab/Simulink toolbox R2012a. Design of DTC induction motor drive, MC with constant switching frequency, speed controller and stability investigation as well as controllability and observabilty with minimum final prediction (FPE steady state error and loss functionality has been carried out precisely.

  3. Mitochondrial matrix delivery using MITO-Porter, a liposome-based carrier that specifies fusion with mitochondrial membranes

    Energy Technology Data Exchange (ETDEWEB)

    Yasuzaki, Yukari; Yamada, Yuma [Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812 (Japan); Harashima, Hideyoshi, E-mail: harasima@pharm.hokudai.ac.jp [Laboratory for Molecular Design of Pharmaceutics, Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812 (Japan)

    2010-06-25

    Mitochondria are the principal producers of energy in cells of higher organisms. It was recently reported that mutations and defects in mitochondrial DNA (mtDNA) are associated with various mitochondrial diseases including a variety of neurodegenerative and neuromuscular diseases. Therefore, an effective mitochondrial gene therapy and diagnosis would be expected to have great medical benefits. To achieve this, therapeutic agents need to be delivered into the innermost mitochondrial space (mitochondrial matrix), which contains the mtDNA pool. We previously reported on the development of MITO-Porter, a liposome-based carrier that introduces macromolecular cargos into mitochondria via membrane fusion. In this study, we provide a demonstration of mitochondrial matrix delivery and the visualization of mitochondrial genes (mtDNA) in living cells using the MITO-Porter. We first prepared MITO-Porter containing encapsulated propidium iodide (PI), a fluorescent dye used to stain nucleic acids to detect mtDNA. We then confirmed the emission of red-fluorescence from PI by conjugation with mtDNA, when the carriers were incubated in the presence of isolated rat liver mitochondria. Finally, intracellular observation by confocal laser scanning microscopy clearly verified that the MITO-Porter delivered PI to the mitochondrial matrix.

  4. D-Glucose as a modifying agent in gelatin/collagen matrix and reservoir nanoparticles for Calendula officinalis delivery.

    Science.gov (United States)

    Lam, P-L; Kok, S H-L; Bian, Z-X; Lam, K-H; Tang, J C-O; Lee, K K-H; Gambari, R; Chui, C-H

    2014-05-01

    Gelatin/Collagen-based matrix and reservoir nanoparticles require crosslinkers to stabilize the formed nanosuspensions, considering that physical instability is the main challenge of nanoparticulate systems. The use of crosslinkers improves the physical integrity of nanoformulations under the-host environment. Aldehyde-based fixatives, such as formaldehyde and glutaraldehyde, have been widely applied to the crosslinking process of polymeric nanoparticles. However, their potential toxicity towards human beings has been demonstrated in many previous studies. In order to tackle this problem, D-glucose was used during nanoparticle formation to stabilize the gelatin/collagen-based matrix wall and reservoir wall for the deliveries of Calendula officinalis powder and oil, respectively. In addition, therapeutic selectivity between malignant and normal cells could be observed. The C. officinalis powder loaded nanoparticles significantly strengthened the anti-cancer effect towards human breast adenocarcinoma MCF7 cells and human hepatoma SKHep1 cells when compared with the free powder. On the contrary, the nanoparticles did not show significant cytotoxicity towards normal esophageal epithelial NE3 cells and human skin keratinocyte HaCaT cells. On the basis of these evidences, D-glucose modified gelatin/collagen matrix nanoparticles containing C. officinalis powder might be proposed as a safer alternative vehicle for anti-cancer treatments. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Mitochondrial matrix delivery using MITO-Porter, a liposome-based carrier that specifies fusion with mitochondrial membranes

    International Nuclear Information System (INIS)

    Yasuzaki, Yukari; Yamada, Yuma; Harashima, Hideyoshi

    2010-01-01

    Mitochondria are the principal producers of energy in cells of higher organisms. It was recently reported that mutations and defects in mitochondrial DNA (mtDNA) are associated with various mitochondrial diseases including a variety of neurodegenerative and neuromuscular diseases. Therefore, an effective mitochondrial gene therapy and diagnosis would be expected to have great medical benefits. To achieve this, therapeutic agents need to be delivered into the innermost mitochondrial space (mitochondrial matrix), which contains the mtDNA pool. We previously reported on the development of MITO-Porter, a liposome-based carrier that introduces macromolecular cargos into mitochondria via membrane fusion. In this study, we provide a demonstration of mitochondrial matrix delivery and the visualization of mitochondrial genes (mtDNA) in living cells using the MITO-Porter. We first prepared MITO-Porter containing encapsulated propidium iodide (PI), a fluorescent dye used to stain nucleic acids to detect mtDNA. We then confirmed the emission of red-fluorescence from PI by conjugation with mtDNA, when the carriers were incubated in the presence of isolated rat liver mitochondria. Finally, intracellular observation by confocal laser scanning microscopy clearly verified that the MITO-Porter delivered PI to the mitochondrial matrix.

  6. Improving Employee Satisfaction Priority through Performance Control Matrix

    Directory of Open Access Journals (Sweden)

    Shun-Hsing Chen

    2014-11-01

    Full Text Available The study addresses Performance Control Matrix (PCM to determine service quality items of priority for improvement. Most businesses focus on customer satisfaction when undertaking surveys of satisfaction and dissatisfaction, while generally neglecting employee satisfaction. Therefore, this study develops an integrated model to improve service quality in Taiwanese finance industry employees. A questionnaire is designed to determine the priority of improvement objectives derived from certain questionnaire items that fall into the improvement zone of the PCM. Ten items are found to fall into the improvement zone of the PCM. The present results show that the finance industry employees surveyed in Taiwan were dissatisfied with their job security, salaries, annual bonus, and fair distribution of operational profits. The ten improvement items mostly belong to two dimensions - ‘Pay and Benefits’ and ‘Motivation’. The managers of the financial institutions should seek to improve these quality attributes by devoting more resources to these items, thus promoting employee satisfaction.

  7. Formulation and evaluation of olanzapine matrix pellets for controlled release.

    Science.gov (United States)

    Vishal Gupta, N; Gowda, Dv; Balamuralidhara, V; Mohammed Khan, S

    2011-01-01

    Olanzapine is an antipsychotic used in treatment of schizophrenia. This research was carried out to design oral controlled release matrix pellets of water insoluble drug Olanzapine (OZ), using blend of Sodium Alginate (SA) and Glyceryl Palmito-Stearate (GPS) as matrix polymers, micro crystalline cellulose (MCC) as spheronizer enhancer and Sodium Lauryl Sulphate (SLS) as pore forming agent. OZ formulations were developed by the pelletization technique by drug loaded pellets and characterized with regard to the drug content, size distribution, Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffraction study (XRD). Stability studies were carried out on the optimized formulation for a period of 90 days at 40±2 °C and 75±5% relative humidity. The drug content was in the range of 93.34-98.12%. The mean particle size of the drug loaded pellets was in the range 1024 to 1087µm. SEM photographs and calculated sphericity factor confirmed that the prepared formulations were spherical in nature. The compatibility between drug and polymers in the drug loaded pellets was confirmed by DSC and FTIR studies. Stability studies indicated that pellets are stable. XRD patterns revealed the crystalline nature of the pure OZ. Loose surface crystal study indicated that crystalline OZ is present in all formulations and more clear in formulation F5. Drug release was controlled for more than 24 hrs and mechanism of the drug release followed by Fickian diffusion. It may be concluded that F5 is an ideal formulation for once a day administration.

  8. Acupuncture as pain relief during delivery: a randomized controlled trial.

    Science.gov (United States)

    Borup, Lissa; Wurlitzer, Winnie; Hedegaard, Morten; Kesmodel, Ulrik S; Hvidman, Lone

    2009-03-01

    Many women need some kind of analgesic treatment to relieve pain during childbirth. The objective of our study was to compare the effect of acupuncture with transcutaneous electric nerve stimulation (TENS) and traditional analgesics for pain relief and relaxation during delivery with respect to pain intensity, birth experience, and obstetric outcome. A randomized controlled trial was conducted with 607 healthy women in labor at term who received acupuncture, TENS, or traditional analgesics. Primary outcomes were the need for pharmacological and invasive methods, level of pain assessed by a visual analogue scale, birth experience and satisfaction with delivery, and pain relief evaluated at 2 months postpartum. Secondary obstetric outcomes were duration of labor, use of oxytocin, mode of delivery, postpartum hemorrhage, Apgar score, and umbilical cord pH value. Analysis complied with the intention-to-treat principle. Use of pharmacological and invasive methods was significantly lower in the acupuncture group (acupuncture vs traditional, p Pain scores were comparable. Acupuncture did not influence the duration of labor or the use of oxytocin. Mean Apgar score at 5 minutes and umbilical cord pH value were significantly higher among infants in the acupuncture group compared with infants in the other groups. Acupuncture reduced the need for pharmacological and invasive methods during delivery. Acupuncture is a good supplement to existing pain relief methods.

  9. Autostereoscopic image creation by hyperview matrix controlled single pixel rendering

    Science.gov (United States)

    Grasnick, Armin

    2017-06-01

    technology just with a simple equation. This formula can be utilized to create a specific hyperview matrix for a certain 3D display - independent of the technology used. A hyperview matrix may contain the references to loads of images and act as an instruction for a subsequent rendering process of particular pixels. Naturally, a single pixel will deliver an image with no resolution and does not provide any idea of the rendered scene. However, by implementing the method of pixel recycling, a 3D image can be perceived, even if all source images are different. It will be proven that several millions of perspectives can be rendered with the support of GPU rendering and benefit from the hyperview matrix. In result, a conventional autostereoscopic display, which is designed to represent only a few perspectives can be used to show a hyperview image by using a suitable hyperview matrix. It will be shown that a millions-of-views-hyperview-image can be presented on a conventional autostereoscopic display. For such an hyperview image it is required that all pixels of the displays are allocated by different source images. Controlled by the hyperview matrix, an adapted renderer can render a full hyperview image in real-time.

  10. Stimuli-Responsive Liposomes for Controlled Drug Delivery

    KAUST Repository

    Li, Wengang

    2014-09-01

    Liposomes are promising drug delivery vesicles due to their biodegradibility, large volume and biocompatibility towards both hydrophilic and hydrophobic drugs. They suffer, however, from poor stability which limits their use in controlled delivery applications. Herein, a novel method was devised for modification of liposomes with small molecules, polymers or nanoparticles to afford stimuli responsive systems that release on demand and stay relatively stable in the absence of the trigger.. This dissertation discusses thermosensitive, pH sensitive, light sensitive and magnetically triggered liposomes that have been prepared for controlled drug delivery application. RAFT polymerization was utilized for the preparation of thermosensitive liposomes (Cholesterol-PNIPAm) and acid-labile liposomes (DOPE-PAA). With low Mw Cholesterol-PNIPAm, the thermosensitive liposomes proved to be effective for controlled release and decreased the cytotoxicity of PNIPAm by eliciting the polymer doses. By crosslinking the DOPE-PAA on liposome surface with acid-labile diamine linkers, DOPE-PAA liposomes were verified to be sensitive at low pH. The effects of polymer structures (linear or hyperbranched) have also been studied for the stability and release properties of liposomes. Finally, a dual-responsive Au@SPIO embedded liposome hybrid (ALHs) was prepared with light-induced “on-and-off” function by photo-thermal process (visible light) and instant release properties triggered by alternating magnetic field, respectively. The ALH system would be further applied into the cellular imaging field as MRI contrast agent.

  11. A remotely operated drug delivery system with dose control

    KAUST Repository

    Yi, Ying

    2017-05-08

    “On demand” implantable drug delivery systems can provide optimized treatments, due to their ability to provide targeted, flexible and precise dose release. However, two important issues that need to be carefully considered in a mature device include an effective actuation stimulus and a controllable dose release mechanism. This work focuses on remotely powering an implantable drug delivery system and providing a high degree of control over the released dose. This is accomplished by integration of a resonance-based wireless power transfer system, a constant voltage control circuit and an electrolytic pump. Upon the activation of the wireless power transfer system, the electrolytic actuator is remotely powered by a constant voltage regardless of movements of the device within an effective range of translation and rotation. This in turn contributes to a predictable dose release rate and greater flexibility in the positioning of external powering source. We have conducted proof-of-concept drug delivery studies using the liquid drug in reservoir approach and the solid drug in reservoir approach, respectively. Our experimental results demonstrate that the range of flow rate is mainly determined by the voltage controlled with a Zener diode and the resistance of the implantable device. The latter can be adjusted by connecting different resistors, providing control over the flow rate to meet different clinical needs. The flow rate can be maintained at a constant level within the effective movement range. When using a solid drug substitute with a low solubility, solvent blue 38, the dose release can be kept at 2.36μg/cycle within the effective movement range by using an input voltage of 10Vpp and a load of 1.5 kΩ, which indicates the feasibility and controllability of our system without any complicated closed-loop sensor.

  12. [Matrix transdermal systems for caffeine delivery based on polymer and emulsion compounds].

    Science.gov (United States)

    Kuznetsova, E G; Kuryleva, O M; Salomatina, L A; Sevast'ianov, V I

    2008-01-01

    The goal of this work was to develop and test transdermal therapeutic systems for caffeine delivery. In vitro experiments showed that the rate of caffeine diffusion through untreated rabbit skin from a transdermal therapeutic systems based on polymer compound containing 50 mg medicine was 67.2 (9.1 microg/cm2h; for a system based on emulsion compound it was 173 (19 microg/cm2h. Methods for studying the caffeine release rate and quantitative measurement of caffeine content in the emulsion-based transdermal therapeutic system were developed. These methods are required to obtain data for standard drug documentation. The results of in vivo experiments in rabbits showed the absence of irritating effect of the emulsion-based transdermal therapeutic system. The obtained data on the specific efficiency of the transdermal therapeutic systems for caffeine delivery (50 mg) in healthy volunteers showed that this medicine could be used as a nonnarcotic psychoactivator for improving mental and physical activities and attention concentration.

  13. The potential of silk and silk-like proteins as natural mucoadhesive biopolymers for controlled drug delivery

    Science.gov (United States)

    Brooks, Amanda

    2015-11-01

    Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1) deliver sensitive biologic molecules, (2) promote intimate contact between the mucosa and the drug, and (3) prolong the drug’s local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  14. The potential of silk and silk-like proteins as natural mucoadhesive biopolymers for controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Amanda E Brooks

    2015-11-01

    Full Text Available Drug delivery across mucus membranes is a particularly effective route of administration due to the large surface area. However, the unique environment present at the mucosa necessitates altered drug formulations designed to (1 deliver sensitive biologic molecules, (2 promote intimate contact between the mucosa and the drug, and (3 prolong the drug’s local residence time. Thus, the pharmaceutical industry has an interest in drug delivery systems formulated around the use of mucoadhesive polymers. Mucoadhesive polymers, both synthetic and biological, have a history of use in local drug delivery. Prominently featured in the literature are chitosan, alginate, and cellulose derivatives. More recently, silk and silk-like derivatives have been explored for their potential as mucoadhesive polymers. Both silkworms and spiders produce sticky silk-like glue substances, sericin and aggregate silk respectively, that may prove an effective, natural matrix for drug delivery to the mucosa. This mini review will explore the potential of silk and silk-like derivatives as a biocompatible mucoadhesive polymer matrix for local controlled drug delivery.

  15. Formulation and in vitro evaluation of Eudragit S-100 coated naproxen matrix tablets for colon-targeted drug delivery system

    Directory of Open Access Journals (Sweden)

    Rohit Mehta

    2013-01-01

    Full Text Available The purpose of the present investigation was to prepare matrix tablets of naproxen using a hydrophobic polymer, i.e., Eudragit RLPO, RSPO, and combination of both, by wet granulation method. The tablets were further coated with different concentrations of Eudragit S-100, a pH-sensitive polymer, by dip immerse method. In vitro drug release studies of tablets were carried out in different dissolution media, i.e., 0.1 N HCl (pH 1.2, phosphate buffers pH 6.8 and 7.4, with or without rat cecal content. The swelling studies of the optimized formulation were carried out. The physicochemical parameters of all the formulations were found to be in compliance with the pharmacopoeial standards. The effect of dissolution medium on the surface of matrix tablet was determined by using Scanning Electron Microscopy technique. The stability studies of all formulations were performed as per ICH guidelines. The results demonstrated that the tablets coated with Eudragit S-100 (2% w/v showed a sustained release of 94.67% for 24 h, but drug release increased to about 98.60% for 24 h in the presence of rat cecal content while the uncoated tablets released the drug within 5 h. With regard to release kinetics, the data were best fitted with the Higuchi model with non-Fickian drug release kinetics mechanism. The stability studies of tablets showed less degradation during accelerated and room temperature storage conditions for 6 months. The enteric-coated Eudragit S-100 coated matrix tablets of naproxen showed promising site-specific drug delivery in the colon region.

  16. Control of extracellular matrix assembly by syndecan-2 proteoglycan

    DEFF Research Database (Denmark)

    Klass, C M; Couchman, J R; Woods, A

    2000-01-01

    Extracellular matrix (ECM) deposition and organization is maintained by transmembrane signaling and integrins play major roles. We now show that a second transmembrane component, syndecan-2 heparan sulfate proteoglycan, is pivotal in matrix assembly. Chinese Hamster Ovary (CHO) cells were stably....... The loss of matrix formation was not caused by a failure to synthesize or externalize ECM components as determined by metabolic labeling or due to differences in surface expression of alpha5 or beta1 integrin. The matrix assembly defect was at the cell surface, since S2deltaS cells also lost the ability...... to rearrange laminin or fibronectin substrates into fibrils and to bind exogenous fibronectin. Transfection of activated alphaIIbalphaLdeltabeta3 integrin into alpha(5)-deficient CHO B2 cells resulted in reestablishment of the previously lost fibronectin matrix. However, cotransfection of this cell line with S...

  17. Recent advances in crystalline and amorphous particulate protein formulations for controlled delivery

    Directory of Open Access Journals (Sweden)

    Sebastian Puhl

    2016-08-01

    Full Text Available The number of particulate delivery systems for biologics is negligible compared to liquid dosage forms, signifying the complications associated with development of solid protein delivery systems. Particulate protein delivery systems can improve stability, reduce viscosity of suspensions at high protein concentration and allow for controlled drug release. This review discusses current advances in controlled delivery of particulate protein formulations. While the focus lies on protein crystals and delivery systems employing protein crystals, amorphous protein particles will also be addressed. Crystallization and precipitations methods and modifications allowing controlled delivery with and without encapsulation are summarized and discussed.

  18. Formulation and pharmacokinetics of multi-layered matrix tablets: Biphasic delivery of diclofenac

    Directory of Open Access Journals (Sweden)

    Ehab Mostafa Elzayat

    2017-07-01

    Full Text Available The rapid availability of the drug at the site of action followed by maintaining its effect for a long period of time is of great clinical importance. Thus, the purpose of the present study was to prepare and evaluate multi-layered matrix tablets of diclofenac using Eudragit RL/RS blend to achieve both immediate and sustained therapeutic effects. Diclofenac potassium (25 mg was incorporated in an outer immediate release layer to provide immediate pain relief whereas diclofenac sodium (75 mg was incorporated in the inner core to provide extended drug release. Wet granulation was employed to prepare the inner core of the tablets that were further layered with an immediate release drug layer in the perforated pan coater. The in-vitro and in-vivo performance of the developed formulation was compared with the marketed products Voltaren® SR 75 mg and Cataflam® 25 mg. The in-vitro drug release of the prepared formulation showed similarity (f2 = 66.19 to the marketed product. The pharmacokinetic study showed no significant difference (p > 0.05 in AUC0-24 and Cmax between the test and reference formulations. The AUC0-24 values were 105.36 ± 83.3 and 92.87 ± 55.53 μg h/ml whereas the Cmax values were 11.25 ± 6.87 and 12.97 ± 8.45 μg/ml, for the test and reference, respectively. The multi-layered tablets were proved to be bioequivalent with the commercially available tablets and were in agreement with the observed in-vitro drug release results. Stable physical characteristics and drug release profiles were observed in both long term and accelerated conditions stability studies.

  19. Development of polymer-polysaccharide hydrogels for controlling drug delivery

    Science.gov (United States)

    Baldwin, Aaron David

    Michael type addition of thiol derivatives to N-ethylmaleimide (NEM) undergoes retro and exchange reactions in the presence of other thiol compounds at physiological pH and temperature. Model studies of NEM conjugated to various thiols (4-mercaptophenylacetic acid (MPA), N-acetylcysteine, or 3-mercaptopropionic acid (MP)), incubated with a naturally occurring reducing agent, glutathione, showed half-lives from 20-80 hrs with extents of conversion from 20-90% for MPA and N-acetylcysteine conjugates. The kinetics of the retro reactions and extent of exchange can be modulated by the Michael donor's reactivity; therefore the degradation of maleimide-thiol adducts could be tuned for controlled release of drugs or degradation of materials at timescales different than those currently possible via disulfide-mediated release. The reduction sensitive maleimide-thiol chemistry was then investigated as a crosslinking mechanism for LMWH hydrogels. Crosslinking maleimide functionalized LMWH with PEG functionalized with thiophenyl functionalities imparted glutathione sensitivity. 4-mercaptophenylpropionic acid and 2,2-dimethyl-3-(4-mercaptophenyl)propionic acid, induced sensitivity to glutathione as shown by a decrease in degradation time of 4x and 5x respectively. The pseudo-first order retro reaction constants were approximately an order of magnitude slower than hydrogels crosslinked via disulfide linkages, indicating the potential use of the retro succinimide-thioether covalent bonds for reduction mediated release and/or degradation with increased blood stability and prolonged drug delivery timescales compared to disulfide chemistries. In summary, this work highlights the use of polymer-polysaccharide hydrogels composed of LMWH and PEG as investigated for drug delivery and as a tool for elucidating a novel reduction sensitive controlled release mechanism.

  20. Linear matrix inequality-based nonlinear adaptive robust control with application to unmanned aircraft systems

    Science.gov (United States)

    Kun, David William

    Unmanned aircraft systems (UASs) are gaining popularity in civil and commercial applications as their lightweight on-board computers become more powerful and affordable, their power storage devices improve, and the Federal Aviation Administration addresses the legal and safety concerns of integrating UASs in the national airspace. Consequently, many researchers are pursuing novel methods to control UASs in order to improve their capabilities, dependability, and safety assurance. The nonlinear control approach is a common choice as it offers several benefits for these highly nonlinear aerospace systems (e.g., the quadrotor). First, the controller design is physically intuitive and is derived from well known dynamic equations. Second, the final control law is valid in a larger region of operation, including far from the equilibrium states. And third, the procedure is largely methodical, requiring less expertise with gain tuning, which can be arduous for a novice engineer. Considering these facts, this thesis proposes a nonlinear controller design method that combines the advantages of adaptive robust control (ARC) with the powerful design tools of linear matrix inequalities (LMI). The ARC-LMI controller is designed with a discontinuous projection-based adaptation law, and guarantees a prescribed transient and steady state tracking performance for uncertain systems in the presence of matched disturbances. The norm of the tracking error is bounded by a known function that depends on the controller design parameters in a known form. Furthermore, the LMI-based part of the controller ensures the stability of the system while overcoming polytopic uncertainties, and minimizes the control effort. This can reduce the number of parameters that require adaptation, and helps to avoid control input saturation. These desirable characteristics make the ARC-LMI control algorithm well suited for the quadrotor UAS, which may have unknown parameters and may encounter external

  1. A delivery system for field application of paratransgenic control.

    Science.gov (United States)

    Arora, Arinder K; Forshaw, Adam; Miller, Thomas A; Durvasula, Ravi

    2015-06-23

    As an alternative to chemical pesticides, paratransgenesis relies on transformation of symbiotic bacteria of an arthropod vector to deliver molecules that disrupt pathogen transmission. For over a decade paratransgenesis has remained a laboratory-based endeavor owing to regulatory concerns regarding introduction of transformed microorganisms into the environment. To facilitate field application of paratransgenic strategies, risk mitigation approaches that address environmental contamination and gene spread must be developed. Using biopolymer manipulation, we introduce a novel microencapsulation platform for containment and targeted delivery of engineered bacteria to the gut of a disease-transmitting arthropod. We demonstrate the first proof of principle of targeted delivery of EPA-approved Pantoea agglomerans E325 in a paratransgenic system to control spread of Pierce's Disease by glassy-winged sharpshooters, (Homalodisca vitripennis) under simulated field conditions. Engineered microcapsules may address regulatory concerns regarding containment of recombinant bacteria and environmental spread of foreign genetic material and may represent an important step in translating paratransgenic science beyond the lab and into the field. We present, for the first time, a microencapsulation strategy to deliver recombinant bacteria to an insect and demonstrate targeted release of bacteria into the physiologically relevant region of the insect gut. This is a first step toward addressing concerns related to field application of recombinant bacteria. Engineered microparticles may decrease environmental contamination, horizontal gene transfer and competition with native species by acting as a barrier between recombinant bacteria and the environment.

  2. Evaluation of Two Olibanum Resins as Rate Controlling Matrix ...

    African Journals Online (AJOL)

    Olibanum is an oleo-gum resin which is economically and culturally valuable product obtained from several species of the genus Boswellia. In this study, the resins extracted from local olibanum: Boswellia papyrifera (Tigray type) and Boswellia rivae (Ogaden type) were evaluated as matrix forming agents in sustained ...

  3. Transdermal delivery of insulin by amidated pectin hydrogel matrix patch in streptozotocin-induced diabetic rats: effects on some selected metabolic parameters.

    Directory of Open Access Journals (Sweden)

    Silindile I Hadebe

    Full Text Available Studies in our laboratory are concerned with developing optional insulin delivery routes based on amidated pectin hydrogel matrix gel. We therefore investigated whether the application of pectin insulin (PI-containing dermal patches of different insulin concentrations sustain controlled release of insulin into the bloodstream of streptozotocin (STZ-induced diabetic rats with concomitant alleviation of diabetic symptoms in target tissues, most importantly, muscle and liver.Oral glucose test (OGT responses to PI dermal matrix patches (2.47, 3.99, 9.57, 16.80 µg/kg prepared by dissolving pectin/insulin in deionised water and solidified with CaCl2 were monitored in diabetic rats given a glucose load after an 18-h fast. Short-term (5 weeks metabolic effects were assessed in animals treated thrice daily with PI patches 8 hours apart. Animals treated with drug-free pectin and insulin (175 µg/kg, s.c. acted as untreated and treated positive controls, respectively. Blood, muscle and liver samples were collected for measurements of selected biochemical parameters.After 5 weeks, untreated diabetic rats exhibited hyperglycaemia and depleted hepatic and muscle glycogen concentrations. Compared to untreated STZ-induced diabetic animals, OGT responses of diabetic rats transdermally applied PI patches exhibited lower blood glucose levels whilst short-term treatments restored hepatic and muscle glycogen concentrations. Plasma insulin concentrations of untreated diabetic rats were low compared with control non-diabetic rats. All PI treatments elevated plasma insulin concentrations of diabetic rats although the levels induced by high doses (9.57 and 16.80 µg/kg were greater than those caused by low doses (2.47 and 3.99 µg/kg but comparable to those in sc insulin treated animals.The data suggest that the PI hydrogel matrix patch can deliver physiologically relevant amounts of pharmacologically active insulin.A new method to administer insulin into the

  4. Transdermal Delivery of Insulin by Amidated Pectin Hydrogel Matrix Patch in Streptozotocin-Induced Diabetic Rats: Effects on Some Selected Metabolic Parameters

    Science.gov (United States)

    Hadebe, Silindile I.; Ngubane, Phikelelani S.; Serumula, Metse R.; Musabayane, Cephas T.

    2014-01-01

    Purpose Studies in our laboratory are concerned with developing optional insulin delivery routes based on amidated pectin hydrogel matrix gel. We therefore investigated whether the application of pectin insulin (PI)-containing dermal patches of different insulin concentrations sustain controlled release of insulin into the bloodstream of streptozotocin (STZ)-induced diabetic rats with concomitant alleviation of diabetic symptoms in target tissues, most importantly, muscle and liver. Methods Oral glucose test (OGT) responses to PI dermal matrix patches (2.47, 3.99, 9.57, 16.80 µg/kg) prepared by dissolving pectin/insulin in deionised water and solidified with CaCl2 were monitored in diabetic rats given a glucose load after an 18-h fast. Short-term (5 weeks) metabolic effects were assessed in animals treated thrice daily with PI patches 8 hours apart. Animals treated with drug-free pectin and insulin (175 µg/kg, sc) acted as untreated and treated positive controls, respectively. Blood, muscle and liver samples were collected for measurements of selected biochemical parameters. Results After 5 weeks, untreated diabetic rats exhibited hyperglycaemia and depleted hepatic and muscle glycogen concentrations. Compared to untreated STZ-induced diabetic animals, OGT responses of diabetic rats transdermally applied PI patches exhibited lower blood glucose levels whilst short-term treatments restored hepatic and muscle glycogen concentrations. Plasma insulin concentrations of untreated diabetic rats were low compared with control non-diabetic rats. All PI treatments elevated plasma insulin concentrations of diabetic rats although the levels induced by high doses (9.57 and 16.80 µg/kg) were greater than those caused by low doses (2.47 and 3.99 µg/kg) but comparable to those in sc insulin treated animals. Conclusions The data suggest that the PI hydrogel matrix patch can deliver physiologically relevant amounts of pharmacologically active insulin. Novelty of the Work A new

  5. Development of time and pH dependent controlled release colon specific delivery of tinidazole

    Directory of Open Access Journals (Sweden)

    2008-08-01

    Full Text Available Purpose: Tinidazole is used in treatment of amoebiasis and other protozoal infections in doses of 2.0 g/ day (60 mg/kg for three days. In the present paper, controlled release formulation of tinidazole was developed with an objective to achieve colon specific drug delivery with reduced frequency of dosing, to minimize gastric side effects and thus to increase patient compliance. Methods: Matrix systems of tinidazole (500 mg were prepared by using swellable and pH dependent polymers like hydroxypropyl methylcellulose (HPMC K4M and K15M and eudragit (eudragit L-100 and S-100. Prepared tablets were enteric coated in order to overcome variability in gastric emptying time and delay in the release, to reduce gastric side effects and to provide prolonged localized action in colon. Process of manufacture was optimized during the scale up studies. Bioavailability study (using parallel group design was carried of on conventional marketed, developed uncoated and enteric coated tablets in healthy human volunteers. Results: Bioavailability study showed that greater portion of tinidazole was released in the large intestine and drug level in plasma was above 4 mg/mL in blood for 24 hours. Conclusion: From the results of this study it appears that, the proposed single enteric coated tinidazole (500 mg tablet per day could be used in place of 3-4 doses of 500 mg tinidazole conventional tablet with better control of drug release for targeted drug delivery. In addition developed colon-specific drug delivery system (CDDS was relatively inexpensive and easy to manufacture using conventional pharmaceutical coating technique.

  6. Acupucture as pain relief during delivery - a randomized controlled trial

    DEFF Research Database (Denmark)

    Borup, Lissa; Wurlitzer, Winnie; Hedegaard, Morten

    2009-01-01

    Background: Many women need some kind of analgesic treatment to relieve pain during childbirth. The objective of our study was to compare the effect of acupuncture with transcutaneous electric nerve stimulation (TENS) and traditional analgesics for pain relief and relaxation during delivery...... with respect to pain intensity, birth experience, and obstetric outcome. Methods: A randomized controlled trial was conducted with 607 healthy women in labor at term who received acupuncture, TENS, or traditional analgesics. Primary outcomes were the need for pharmacological and invasive methods, level of pain...... with the intention-to-treat principle. Results: Use of pharmacological and invasive methods was significantly lower in the acupuncture group (acupuncture vs traditional, p acupuncture vs TENS, p = 0.031). Pain scores were comparable. Acupuncture did not influence the duration of labor or the use of oxytocin...

  7. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    Science.gov (United States)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z. V. P.

    2015-03-01

    In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms.

  8. Synthesis of thermosensitive magnetic nanocarrier for controlled sorafenib delivery

    Energy Technology Data Exchange (ETDEWEB)

    Heidarinasab, Amir [Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Ahmad Panahi, Homayon [Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Faramarzi, Mehdi, E-mail: faramarzi.iaug@gmail.com [Department of Chemical Engineering, Science and Research Branch, Islamic Azad University, Tehran (Iran, Islamic Republic of); Farjadian, Fatemeh [Pharmaceutical Sciences Research Center, Faculty of Pharmacy, Shiraz University of Medical Sciences, Shiraz (Iran, Islamic Republic of)

    2016-10-01

    sorafenib delivery. • The TSMNC has high adsorption capacity at 25 °C. • The Fickian diffusion explain well the release mechanism • The TSMNC has desirable controlled release at 45 °C.

  9. The origins and evolution of "controlled" drug delivery systems.

    Science.gov (United States)

    Hoffman, Allan S

    2008-12-18

    This paper describes the earliest days when the "controlled drug delivery" (CDD) field began, the pioneers who launched this exciting and important field, and the key people who came after them. It traces the evolution of the field from its origins in the 1960s to (a) the 1970s and 1980s, when numerous macroscopic "controlled" drug delivery (DD) devices and implants were designed for delivery as mucosal inserts (e.g., in the eye or vagina), as implants (e.g., sub-cutaneous or intra-muscular), as ingestible capsules (e.g., in the G-I tract), as topical patches (e.g., on the skin), and were approved for clinical use, to (b) the 1980s and 1990s when microscopic degradable polymer depot DD systems (DDS) were commercialized, and to (c) the currently very active and exciting nanoscopic era of targeted nano-carriers, in a sense bringing to life Ehrlich's imagined concept of the "Magic Bullet". The nanoscopic era began with systems proposed in the 1970s, that were first used in the clinic in the 1980s, and which came of age in the 1990s, and which are presently evolving into many exciting and clinically successful products in the 2000s. Most of these have succeeded because of the emergence of three key technologies: (1) PEGylation, (2) active targeting to specific cells by ligands conjugated to the DDS, or passive targeting to solid tumors via the EPR effect. The author has been personally involved in the origins and evolution of this field for the past 38 years (see below), and this review includes information that was provided to him by many researchers in this field about the history of various developments. Thus, this paper is based on his own personal involvements in the CDD field, along with many historical anecdotes provided by the key pioneers and researchers in the field. Because of the huge literature of scientific papers on CDD systems, this article attempts to limit examples to those that have been approved for clinical use, or are currently in clinical trials

  10. Predictors for failure of vacuum-assisted vaginal delivery: a case-control study

    NARCIS (Netherlands)

    Verhoeven, Corine J.; Nuij, Chelly; Janssen-Rolf, Christel R. M.; Schuit, Ewoud; Bais, Joke M. J.; Oei, S. Guid; Mol, Ben Willem J.

    2016-01-01

    To identify potential predictors for failed vacuum-assisted delivery. Retrospective case-control study conducted in two perinatal centers in the Netherlands. Cases were women who underwent a failed vacuum-assisted delivery between 1997 and 2011. A failed vacuum extraction was defined as a delivery

  11. Controlled Delivery of Human Cells by Temperature Responsive Microcapsules

    Science.gov (United States)

    Mak, W.C.; Olesen, K.; Sivlér, P.; Lee, C.J.; Moreno-Jimenez, I.; Edin, J.; Courtman, D.; Skog, M.; Griffith, M.

    2015-01-01

    Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line—human umbilical vein endothelial cells (HUVECs). While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation. PMID:26096147

  12. Controlled Delivery of Human Cells by Temperature Responsive Microcapsules

    Directory of Open Access Journals (Sweden)

    W.C. Mak

    2015-06-01

    Full Text Available Cell therapy is one of the most promising areas within regenerative medicine. However, its full potential is limited by the rapid loss of introduced therapeutic cells before their full effects can be exploited, due in part to anoikis, and in part to the adverse environments often found within the pathologic tissues that the cells have been grafted into. Encapsulation of individual cells has been proposed as a means of increasing cell viability. In this study, we developed a facile, high throughput method for creating temperature responsive microcapsules comprising agarose, gelatin and fibrinogen for delivery and subsequent controlled release of cells. We verified the hypothesis that composite capsules combining agarose and gelatin, which possess different phase transition temperatures from solid to liquid, facilitated the destabilization of the capsules for cell release. Cell encapsulation and controlled release was demonstrated using human fibroblasts as model cells, as well as a therapeutically relevant cell line—human umbilical vein endothelial cells (HUVECs. While such temperature responsive cell microcapsules promise effective, controlled release of potential therapeutic cells at physiological temperatures, further work will be needed to augment the composition of the microcapsules and optimize the numbers of cells per capsule prior to clinical evaluation.

  13. Controlled release and intracellular protein delivery from mesoporous silica nanoparticles.

    Science.gov (United States)

    Deodhar, Gauri V; Adams, Marisa L; Trewyn, Brian G

    2017-01-01

    Protein therapeutics are promising candidates for disease treatment due to their high specificity and minimal adverse side effects; however, targeted protein delivery to specific sites has proven challenging. Mesoporous silica nanoparticles (MSN) have demonstrated to be ideal candidates for this application, given their high loading capacity, biocompatibility, and ability to protect host molecules from degradation. These materials exhibit tunable pore sizes, shapes and volumes, and surfaces which can be easily functionalized. This serves to control the movement of molecules in and out of the pores, thus entrapping guest molecules until a specific stimulus triggers release. In this review, we will cover the benefits of using MSN as protein therapeutic carriers, demonstrating that there is great diversity in the ways MSN can be used to service proteins. Methods for controlling the physical dimensions of pores via synthetic conditions, applications of therapeutic protein loaded MSN materials in cancer therapies, delivering protein loaded MSN materials to plant cells using biolistic methods, and common stimuli-responsive functionalities will be discussed. New and exciting strategies for controlled release and manipulation of proteins are also covered in this review. While research in this area has advanced substantially, we conclude this review with future challenges to be tackled by the scientific community. Copyright © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Bioengineered microparticles for controlled drug delivery to the lungs

    OpenAIRE

    Sivadas, Neeraj

    2010-01-01

    Traditional formulations for pulmonary drug delivery mainly focused on two approaches: (i) Dissolving or suspending the drug in a solvent or propellant to produce liquid aerosols or (ii) Blending drug particulates with dry carrier particles typically composed of sugars. Although effective for localised delivery of small drug molecules, these methods did not meet the complex formulation and delivery challenges posed by the newer biotechnology-derived medicines. One of the many avenues being ex...

  15. Delivery of an engineered HGF fragment in an extracellular matrix-derived hydrogel prevents negative LV remodeling post-myocardial infarction.

    Science.gov (United States)

    Sonnenberg, Sonya B; Rane, Aboli A; Liu, Cassie J; Rao, Nikhil; Agmon, Gillie; Suarez, Sophia; Wang, Raymond; Munoz, Adam; Bajaj, Vaibhav; Zhang, Shirley; Braden, Rebecca; Schup-Magoffin, Pamela J; Kwan, Oi Ling; DeMaria, Anthony N; Cochran, Jennifer R; Christman, Karen L

    2015-03-01

    Hepatocyte growth factor (HGF) has been shown to have anti-fibrotic, pro-angiogenic, and cardioprotective effects; however, it is highly unstable and expensive to manufacture, hindering its clinical translation. Recently, a HGF fragment (HGF-f), an alternative c-MET agonist, was engineered to possess increased stability and recombinant expression yields. In this study, we assessed the potential of HGF-f, delivered in an extracellular matrix (ECM)-derived hydrogel, as a potential treatment for myocardial infarction (MI). HGF-f protected cardiomyocytes from serum-starvation and induced down-regulation of fibrotic markers in whole cardiac cell isolate compared to the untreated control. The ECM hydrogel prolonged release of HGF-f compared to collagen gels, and in vivo delivery of HGF-f from ECM hydrogels mitigated negative left ventricular (LV) remodeling, improved fractional area change (FAC), and increased arteriole density in a rat myocardial infarction model. These results indicate that HGF-f may be a viable alternative to using recombinant HGF, and that an ECM hydrogel can be employed to increase growth factor retention and efficacy. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Extensions of linear-quadratic control, optimization and matrix theory

    CERN Document Server

    Jacobson, David H

    1977-01-01

    In this book, we study theoretical and practical aspects of computing methods for mathematical modelling of nonlinear systems. A number of computing techniques are considered, such as methods of operator approximation with any given accuracy; operator interpolation techniques including a non-Lagrange interpolation; methods of system representation subject to constraints associated with concepts of causality, memory and stationarity; methods of system representation with an accuracy that is the best within a given class of models; methods of covariance matrix estimation;methods for low-rank mat

  17. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z.V.P., E-mail: zvpm2000@yahoo.com

    2015-03-01

    Graphical abstract: - Highlights: • Porous silicon (PSi) was fabricated by electrochemical etching process. • Micro- and nanoparticles were prepared by ultrasonic fracture of PSi films. • Acyclovir was loaded into native, oxidized, and hydrosilylated PSi particles. • Micro- and nanoparticles displays controlled release behaviour for several days. • Drug release behaviour and release kinetics from PSi particles were studied. - Abstract: In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms.

  18. Controlled delivery of acyclovir from porous silicon micro- and nanoparticles

    International Nuclear Information System (INIS)

    Maniya, Nalin H.; Patel, Sanjaykumar R.; Murthy, Z.V.P.

    2015-01-01

    Graphical abstract: - Highlights: • Porous silicon (PSi) was fabricated by electrochemical etching process. • Micro- and nanoparticles were prepared by ultrasonic fracture of PSi films. • Acyclovir was loaded into native, oxidized, and hydrosilylated PSi particles. • Micro- and nanoparticles displays controlled release behaviour for several days. • Drug release behaviour and release kinetics from PSi particles were studied. - Abstract: In this work, micro- and nanoparticles of porous silicon (PSi) are demonstrated to act as effective carrier for the controlled delivery of acyclovir (ACV). PSi films prepared by electrochemical etching were fractured by ultrasonication to prepare micro- and nanoparticles. PSi native particles were thermally oxidized (TOPSi) and thermally hydrosilylated using undecylenic acid (UnPSi). PSi particles with three different surface chemistries were then loaded with ACV by physical adsorption and covalent attachment. Such particles were characterized by scanning electron microscopy, dynamic light scattering, and Fourier transform infrared spectroscopy. In vitro ACV release experiments in phosphate buffered saline showed sustained release behaviour from both micro- and nanoparticles and order of release was found to be native PSi > TOPSi > UnPSi. Drug release kinetics study using Korsmeyer-Peppas model suggested a combination of both drug diffusion and Si scaffold erosion based drug release mechanisms

  19. Controlling chitosan-based encapsulation for protein and vaccine delivery

    Science.gov (United States)

    Koppolu, Bhanu prasanth; Smith, Sean G.; Ravindranathan, Sruthi; Jayanthi, Srinivas; Kumar, Thallapuranam K.S.; Zaharoff, David A.

    2014-01-01

    Chitosan-based nano/microencapsulation is under increasing investigation for the delivery of drugs, biologics and vaccines. Despite widespread interest, the literature lacks a defined methodology to control chitosan particle size and drug/protein release kinetics. In this study, the effects of precipitation-coacervation formulation parameters on chitosan particle size, protein encapsulation efficiency and protein release were investigated. Chitosan particle sizes, which ranged from 300 nm to 3 μm, were influenced by chitosan concentration, chitosan molecular weight and addition rate of precipitant salt. The composition of precipitant salt played a significant role in particle formation with upper Hofmeister series salts containing strongly hydrated anions yielding particles with a low polydispersity index (PDI) while weaker anions resulted in aggregated particles with high PDIs. Sonication power had minimal effect on mean particle size, however, it significantly reduced polydispersity. Protein loading efficiencies in chitosan nano/microparticles, which ranged from 14.3% to 99.2%, was inversely related to the hydration strength of precipitant salts, protein molecular weight and directly related to the concentration and molecular weight of chitosan. Protein release rates increased with particle size and were generally inversely related to protein molecular weight. This study demonstrates that chitosan nano/microparticles with high protein loading efficiencies can be engineered with well-defined sizes and controllable release kinetics through manipulation of specific formulation parameters. PMID:24560459

  20. Oral controlled release drug delivery system and Characterization of oral tablets; A review

    Directory of Open Access Journals (Sweden)

    Muhammad Zaman

    2016-01-01

    Full Text Available Oral route of drug administration is considered as the safest and easiest route of drug administration. Control release drug delivery system is the emerging trend in the pharmaceuticals and the oral route is most suitable for such kind of drug delivery system. Oral route is more convenient for It all age group including both pediatric and geriatrics. There are various systems which are adopted to deliver drug in a controlled manner to different target sites through oral route. It includes diffusion controlled drug delivery systems; dissolution controlled drug delivery systems, osmotically controlled drug delivery systems, ion-exchange controlled drug delivery systems, hydrodynamically balanced systems, multi-Particulate drug delivery systems and microencapsulated drug delivery system. The systems are formulated using different natural, semi-synthetic and synthetic polymers. The purpose of the review is to provide information about the orally controlled drug delivery system, polymers which are used to formulate these systems and characterizations of one of the most convenient dosage form which is the tablets. 

  1. Optimization of matrix tablets controlled drug release using Elman dynamic neural networks and decision trees.

    Science.gov (United States)

    Petrović, Jelena; Ibrić, Svetlana; Betz, Gabriele; Đurić, Zorica

    2012-05-30

    The main objective of the study was to develop artificial intelligence methods for optimization of drug release from matrix tablets regardless of the matrix type. Static and dynamic artificial neural networks of the same topology were developed to model dissolution profiles of different matrix tablets types (hydrophilic/lipid) using formulation composition, compression force used for tableting and tablets porosity and tensile strength as input data. Potential application of decision trees in discovering knowledge from experimental data was also investigated. Polyethylene oxide polymer and glyceryl palmitostearate were used as matrix forming materials for hydrophilic and lipid matrix tablets, respectively whereas selected model drugs were diclofenac sodium and caffeine. Matrix tablets were prepared by direct compression method and tested for in vitro dissolution profiles. Optimization of static and dynamic neural networks used for modeling of drug release was performed using Monte Carlo simulations or genetic algorithms optimizer. Decision trees were constructed following discretization of data. Calculated difference (f(1)) and similarity (f(2)) factors for predicted and experimentally obtained dissolution profiles of test matrix tablets formulations indicate that Elman dynamic neural networks as well as decision trees are capable of accurate predictions of both hydrophilic and lipid matrix tablets dissolution profiles. Elman neural networks were compared to most frequently used static network, Multi-layered perceptron, and superiority of Elman networks have been demonstrated. Developed methods allow simple, yet very precise way of drug release predictions for both hydrophilic and lipid matrix tablets having controlled drug release. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Acupuncture as pain relief during delivery: a randomized controlled trial

    DEFF Research Database (Denmark)

    Borup, Lissa; Wurlitzer, Winnie; Hedegaard, Morten

    2009-01-01

    BACKGROUND: Many women need some kind of analgesic treatment to relieve pain during childbirth. The objective of our study was to compare the effect of acupuncture with transcutaneous electric nerve stimulation (TENS) and traditional analgesics for pain relief and relaxation during delivery...... assessed by a visual analogue scale, birth experience and satisfaction with delivery, and pain relief evaluated at 2 months postpartum. Secondary obstetric outcomes were duration of labor, use of oxytocin, mode of delivery, postpartum hemorrhage, Apgar score, and umbilical cord pH value. Analysis complied...... to existing pain relief methods....

  3. Controlling excited-state contamination in nucleon matrix elements

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Boram; Gupta, Rajan; Bhattacharya, Tanmoy; Engelhardt, Michael; Green, Jeremy; Joó, Bálint; Lin, Huey-Wen; Negele, John; Orginos, Kostas; Pochinsky, Andrew; Richards, David; Syritsyn, Sergey; Winter, Frank

    2016-06-01

    We present a detailed analysis of methods to reduce statistical errors and excited-state contamination in the calculation of matrix elements of quark bilinear operators in nucleon states. All the calculations were done on a 2+1 flavor ensemble with lattices of size $32^3 \\times 64$ generated using the rational hybrid Monte Carlo algorithm at $a=0.081$~fm and with $M_\\pi=312$~MeV. The statistical precision of the data is improved using the all-mode-averaging method. We compare two methods for reducing excited-state contamination: a variational analysis and a two-state fit to data at multiple values of the source-sink separation $t_{\\rm sep}$. We show that both methods can be tuned to significantly reduce excited-state contamination and discuss their relative advantages and cost-effectiveness. A detailed analysis of the size of source smearing used in the calculation of quark propagators and the range of values of $t_{\\rm sep}$ needed to demonstrate convergence of the isovector charges of the nucleon to the $t_{\\rm sep} \\to \\infty $ estimates is presented.

  4. The application of nanomaterials in controlled drug delivery for bone regeneration.

    Science.gov (United States)

    Shi, Shuo; Jiang, Wenbao; Zhao, Tianxiao; Aifantis, Katerina E; Wang, Hui; Lin, Lei; Fan, Yubo; Feng, Qingling; Cui, Fu-zhai; Li, Xiaoming

    2015-12-01

    Bone regeneration is a complicated process that involves a series of biological events, such as cellular recruitment, proliferation and differentiation, and so forth, which have been found to be significantly affected by controlled drug delivery. Recently, a lot of research studies have been launched on the application of nanomaterials in controlled drug delivery for bone regeneration. In this article, the latest research progress in this area regarding the use of bioceramics-based, polymer-based, metallic oxide-based and other types of nanomaterials in controlled drug delivery for bone regeneration are reviewed and discussed, which indicates that the controlling drug delivery with nanomaterials should be a very promising treatment in orthopedics. Furthermore, some new challenges about the future research on the application of nanomaterials in controlled drug delivery for bone regeneration are described in the conclusion and perspectives part. Copyright © 2015 Wiley Periodicals, Inc.

  5. Simple Power Control for Sensorless Induction Motor Drives Fed by a Matrix Converter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Lee, Kyo Beum

    2008-01-01

    This paper presents a new and simple method for sensorless control of matrix converter drives using a power flowing to the motor. The proposed control algorithm is based on controlling the instantaneous real and imaginary powers into the induction motor. To improve low-speed sensorless performance...

  6. Two-Link Flexible Manipulator Control Using Sliding Mode Control Based Linear Matrix Inequality

    Science.gov (United States)

    Zulfatman; Marzuki, Mohammad; Alif Mardiyah, Nur

    2017-04-01

    Two-link flexible manipulator is a manipulator robot which at least one of its arms is made of lightweight material and not rigid. Flexible robot manipulator has some advantages over the rigid robot manipulator, such as lighter, requires less power and costs, and to result greater payload. However, suitable control algorithm to maintain the two-link flexible robot manipulator in accurate positioning is very challenging. In this study, sliding mode control (SMC) was employed as robust control algorithm due to its insensitivity on the system parameter variations and the presence of disturbances when the system states are sliding on a sliding surface. SMC algorithm was combined with linear matrix inequality (LMI), which aims to reduce the effects of chattering coming from the oscillation of the state during sliding on the sliding surface. Stability of the control algorithm is guaranteed by Lyapunov function candidate. Based on simulation works, SMC based LMI resulted in better performance improvements despite the disturbances with significant chattering reduction. This was evident from the decline of the sum of squared tracking error (SSTE) and the sum of squared of control input (SSCI) indexes respectively 25.4% and 19.4%.

  7. Chitosan microparticles for the controlled delivery of fluoride.

    Science.gov (United States)

    Keegan, Gemma M; Smart, John D; Ingram, Matthew J; Barnes, Lara-Marie; Burnett, Gary R; Rees, Gareth D

    2012-03-01

    principle in vivo. Spray-drying is a low-cost route for the manufacture of bioadhesive chitosan/fluoride microparticles which can be exploited as controlled fluoride release agents to aid fluoride retention in the oral cavity. The potential exists to optimise release profiles to suit the delivery format thereby maximising the cariostatic benefits. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. A computer-controlled conformal radiotherapy system. III: graphical simulation and monitoring of treatment delivery

    International Nuclear Information System (INIS)

    Kessler, Marc L.; McShan, Daniel L.; Fraass, Benedick A.

    1995-01-01

    Purpose: Safe and efficient delivery of radiotherapy using computer-controlled machines requires new procedures to design and verify the actual delivery of these treatments. Graphical simulation and monitoring techniques for treatment delivery have been developed for this purpose. Methods and Materials: A graphics-based simulator of the treatment machine and a set of procedures for creating and manipulating treatment delivery scripts are used to simulate machine motions, detect collisions, and monitor machine positions during treatment. The treatment delivery simulator is composed of four components: a three-dimensional dynamic model of the treatment machine; a motion simulation and collision detection algorithm, user-interface widgets that mimic the treatment machine's control and readout devices; and an icon-based interface for creating and manipulating treatment delivery scripts. These components are used in a stand-alone fashion for interactive treatment delivery planning and integrated with a machine control system for treatment implementation and monitoring. Results: A graphics-based treatment delivery simulator and a set of procedures for planning and monitoring computer-controlled treatment delivery have been developed and implemented as part of a comprehensive computer-controlled conformal radiotherapy system. To date, these techniques have been used to design and help monitor computer-controlled treatments on a radiotherapy machine for more than 200 patients. Examples using these techniques for treatment delivery planning and on-line monitoring of machine motions during therapy are described. Conclusion: A system that provides interactive graphics-based tools for defining the sequence of machine motions, simulating treatment delivery including collision detection, and presenting the therapists with continual visual feedback from the treatment machine has been successfully implemented for routine clinical use as part of an overall system for computer-controlled

  9. Fuzzy attitude control of solar sail via linear matrix inequalities

    Science.gov (United States)

    Baculi, Joshua; Ayoubi, Mohammad A.

    2017-09-01

    This study presents a fuzzy tracking controller based on the Takagi-Sugeno (T-S) fuzzy model of the solar sail. First, the T-S fuzzy model is constructed by linearizing the existing nonlinear equations of motion of the solar sail. Then, the T-S fuzzy model is used to derive the state feedback controller gains for the Twin Parallel Distributed Compensation (TPDC) technique. The TPDC tracks and stabilizes the attitude of the solar sail to any desired state in the presence of parameter uncertainties and external disturbances while satisfying actuator constraints. The performance of the TPDC is compared to a PID controller that is tuned using the Ziegler-Nichols method. Numerical simulation shows the TPDC outperforms the PID controller when stabilizing the solar sail to a desired state.

  10. Controlled delivery of aspirin: effect of aspirin on polymer degradation and in vitro release from PLGA based phase sensitive systems.

    Science.gov (United States)

    Tang, Yu; Singh, Jagdish

    2008-06-05

    The objective of this study was to develop poly (d,l-lactide-co-glycolide) (PLGA) based injectable phase sensitive in situ gel forming delivery system for controlled delivery of aspirin, and to characterize the effect of drug/polymer interaction on the in vitro release of aspirin and polymer degradation. Aspirin was dissolved into PLGA solution in 1-methyl-2-pyrrolidone. Poly(ethylene glycol)400 was used as plasticizer to reduce initial burst release. The solution formulation was injected into aqueous release medium to form a gel depot. Released samples were withdrawn periodically and assayed for aspirin content by high performance liquid chromatography. The effect of aspirin on the degradation of PLGA matrix was evaluated using Proton Nuclear Magnetic Resonance and Gel Permeation Chromatography. PLGA based in situ gel forming formulations controlled the in vitro release of aspirin for 7 days only. Analysis of PLGA matrix residuals revealed that PLGA in aspirin loaded formulations exhibited a significantly (pdegradation compared to blank formulations. These findings suggest that aspirin causes an unusually faster degradation of PLGA. Such faster degradation of PLGA has not been noticed for any other drugs reported in the literature.

  11. Comparative Studies of Different Control Strategies of a Dynamic Voltage Restorer Based on Matrix Converter

    Directory of Open Access Journals (Sweden)

    Amin Shabanpour

    2012-01-01

    Full Text Available A dynamic voltage restorer (DVR with no energy storage is studied. By using a matrix converter instead of the conventional AC/DC/AC converters, elimination of the DC-link capacitor is possible. The switching algorithm of matrix converter is the space vector modulation. There are different compensation algorithms to control the conventional DVR. These methods have been analyzed in this paper for the proposed matrix-converter-based DVR. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived, and the characteristics of algorithms are compared with each other.

  12. Developing Learning Tool of Control System Engineering Using Matrix Laboratory Software Oriented on Industrial Needs

    Science.gov (United States)

    Isnur Haryudo, Subuh; Imam Agung, Achmad; Firmansyah, Rifqi

    2018-04-01

    The purpose of this research is to develop learning media of control technique using Matrix Laboratory software with industry requirement approach. Learning media serves as a tool for creating a better and effective teaching and learning situation because it can accelerate the learning process in order to enhance the quality of learning. Control Techniques using Matrix Laboratory software can enlarge the interest and attention of students, with real experience and can grow independent attitude. This research design refers to the use of research and development (R & D) methods that have been modified by multi-disciplinary team-based researchers. This research used Computer based learning method consisting of computer and Matrix Laboratory software which was integrated with props. Matrix Laboratory has the ability to visualize the theory and analysis of the Control System which is an integration of computing, visualization and programming which is easy to use. The result of this instructional media development is to use mathematical equations using Matrix Laboratory software on control system application with DC motor plant and PID (Proportional-Integral-Derivative). Considering that manufacturing in the field of Distributed Control systems (DCSs), Programmable Controllers (PLCs), and Microcontrollers (MCUs) use PID systems in production processes are widely used in industry.

  13. Synthesis of Biodegradable Polymer Micro- and Nanoparticles for Controlled Drug Delivery by Multiplexed Electrosprays

    Science.gov (United States)

    Almeria, Begona

    . The compactness of the polymer matrix is defined by the competition between the solvent evaporation and polymer diffusion process occurring inside the droplets during their flight towards the collector plate. Finally, by judiciously selecting polymer molecular weight, concentration, and solution flow rate, we can control the order in which polymer entanglements and Coulomb fission occur in the droplets and their relative significance, which subsequently governs the morphology of the resulting polymer particles. In a single-step flow process, particles can be made to encapsulate the agent with high efficiency and be coated with emulsifiers that either stabilizes their suspension in solution or facilitate further functionalization for targeted drug delivery. The coating process allows for the surface modification of the particles without changes in particle size or morphology, with excellent particulate reproducibility and with minimal loss of drug (>94% encapsulation efficiency). This synthesis technique is well suited for massive scale-up using microfabricated, multiplexed arrays consisting of multiple electrospray nozzles operating in parallel. Importantly, throughout this series of studies efforts were made to remove the synthesis approach from the all too common empiricism of a large fraction of the literature on materials synthesis, and to establish fundamental criteria that would allow for the generation of particles of prescribed size, morphology and consistency from first principles. As a result, the extension of the approach to different drug/polymer combinations should be facilitated.

  14. Predictive current control with instantaneous reactive power minimization for a four-leg indirect matrix converter

    OpenAIRE

    Garcia, Cristian F.; Rivera, Marco E.; Rodriguez, Jose R.; Wheeler, Patrick; Pena, Ruben S.

    2017-01-01

    This paper presents the experimental valida¬tion of a predictive current control strategy with minimiza¬tion of the instantaneous reactive input power for a Four-Leg Indirect Matrix Converter (4Leg-IMC). The topology includes an input matrix converter stage, which provides the dc voltage for a four-leg voltage source converter (VSC) output stage. The VSC’s fourth leg provides a path for the zero sequence load current. The control technique is based on a finite control set model predictive con...

  15. Polymer carriers for targeted drug delivery and controlled drug release

    Czech Academy of Sciences Publication Activity Database

    Ulbrich, Karel; Pechar, Michal; Etrych, Tomáš; Jelínková, Markéta; Kovář, Marek; Říhová, Blanka

    2003-01-01

    Roč. 10, č. 1 (2003), s. 3-4 ISSN 1211-5894 R&D Projects: GA ČR GA305/02/1425; GA AV ČR IAA4050201 Institutional research plan: CEZ:AV0Z5020903; CEZ:AV0Z4050913 Keywords : HPMA copolymers * drug targeting * drug delivery Subject RIV: CD - Macromolecular Chemistry

  16. Dynamic pricing and inventory control with delivery flexibility

    DEFF Research Database (Denmark)

    Chen, Wen; He, Ying

    2018-01-01

    We study a multi-period inventory system with price-sensitive demand and uncertain supplier, focusing on the advantage of delivery flexibility. The optimal pricing and inventory replenishment decisions are explored. We also investigate the changes of marginal profit, optimal order quantities...

  17. A Controlled Drug-Delivery Experiment Using Alginate Beads

    Science.gov (United States)

    Farrell, Stephanie; Vernengo, Jennifer

    2012-01-01

    This paper describes a simple, cost-effective experiment which introduces students to drug delivery and modeling using alginate beads. Students produce calcium alginate beads loaded with drug and measure the rate of release from the beads for systems having different stir rates, geometries, extents of cross-linking, and drug molecular weight.…

  18. Predictors for failure of vacuum-assisted vaginal delivery : A case-control study

    NARCIS (Netherlands)

    Verhoeven, Corine J M; Nuij, Chelly; Janssen-Rolf, Christel R M; Schuit, Ewoud|info:eu-repo/dai/nl/341652385; Bais, Joke M J; Oei, S. Guid; Mol, Ben Willem J

    2016-01-01

    Objective To identify potential predictors for failed vacuum-assisted delivery. Study design Retrospective case-control study conducted in two perinatal centers in the Netherlands. Cases were women who underwent a failed vacuum-assisted delivery between 1997 and 2011. A failed vacuum extraction was

  19. Design Project on Controlled-Release Drug Delivery Devices: Implementation, Management, and Learning Experiences

    Science.gov (United States)

    Xu, Qingxing; Liang, Youyun; Tong, Yen Wah; Wang, Chi-Hwa

    2010-01-01

    A design project that focuses on the subject of controlled-release drug delivery devices is presented for use in an undergraduate course on mass transfer. The purpose of the project is to introduce students to the various technologies used in the fabrication of drug delivery systems and provide a practical design exercise for understanding the…

  20. Materials for Pharmaceutical Dosage Forms: Molecular Pharmaceutics and Controlled Release Drug Delivery Aspects

    Directory of Open Access Journals (Sweden)

    Patrick P. DeLuca

    2010-09-01

    Full Text Available Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development.

  1. Materials for pharmaceutical dosage forms: molecular pharmaceutics and controlled release drug delivery aspects.

    Science.gov (United States)

    Mansour, Heidi M; Sohn, Minji; Al-Ghananeem, Abeer; Deluca, Patrick P

    2010-09-15

    Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles) over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development.

  2. In Situ Dual Cross-Linking of Neat Biogel with Controlled Mechanical and Delivery Properties.

    Science.gov (United States)

    Kelmansky, Regina; Shagan, Alona; Rozenblit, Boris; Omar, Rawan; Lufton, Maayan; Mizrahi, Boaz

    2017-10-02

    Injectable biomaterials play a critical role in many biomedical applications. These materials, however, often have limitations in mechanical and drug-eluting properties attributed to their high water content and the weak secondary forces holding them together. Here we describe a new injectable material based on two complementary water-free, prepolymers modified with succinimidyl carbonate (SC) or with NH 2 end groups that form a stiff matrix upon mixing. Cross-linking involves an immediate reaction between PEG 4 -SC and PEG 4 -NH 2 that forms carbamate bonds and a delayed reaction of PEG 4 -SC with hydroxyl functional groups that forms carbonate bonds. The mechanical properties, swelling, and erosion kinetics of this biomaterial can be fine-tuned by varying the ratio between the two prepolymers. Bovine serum albumin and poorly water-soluble free base doxorubicin were readily loaded into this system, resulting in a high drug loading content attributed to the absence of water in the formulation. Controlled release over a period of 1 to 30 days was observed, depending on mixture composition and drug properties. The injectable nature of the formulation, its tailored mechanical properties, the fact that it can be cross-linked by two separate mechanisms, and its ability to incorporate and release hydrophilic and hydrophobic drugs make it very attractive as a drug delivery system.

  3. Structured emulsion-based delivery systems: controlling the digestion and release of lipophilic food components.

    Science.gov (United States)

    McClements, David Julian; Li, Yan

    2010-09-15

    There is a need for edible delivery systems to encapsulate, protect and release bioactive and functional lipophilic constituents within the food and pharmaceutical industries. These delivery systems could be used for a number of purposes: controlling lipid bioavailability; targeting the delivery of bioactive components within the gastrointestinal tract; and designing food matrices that delay lipid digestion and induce satiety. Emulsion technology is particularly suited for the design and fabrication of delivery systems for lipids. In this article we provide an overview of a number of emulsion-based technologies that can be used as edible delivery systems by the food and other industries, including conventional emulsions, nanoemulsions, multilayer emulsions, solid lipid particles, and filled hydrogel particles. Each of these delivery systems can be produced from food-grade (GRAS) ingredients (e.g., lipids, proteins, polysaccharides, surfactants, and minerals) using relatively simple processing operations (e.g., mixing, homogenizing, and thermal processing). The structure, preparation, and utilization of each type of delivery system for controlling lipid digestion are discussed. This knowledge can be used to select the most appropriate emulsion-based delivery system for specific applications, such as encapsulation, controlled digestion, and targeted release. Copyright 2010 Elsevier B.V. All rights reserved.

  4. DNA Nanotechnology for Precise Control over Drug Delivery and Gene Therapy.

    Science.gov (United States)

    Angell, Chava; Xie, Sibai; Zhang, Liangfang; Chen, Yi

    2016-03-02

    Nanomedicine has been growing exponentially due to its enhanced drug targeting and reduced drug toxicity. It uses the interactions where nanotechnological components and biological systems communicate with each other to facilitate the delivery performance. At this scale, the physiochemical properties of delivery systems strongly affect their capacities. Among current delivery systems, DNA nanotechnology shows many advantages because of its unprecedented engineering abilities. Through molecular recognition, DNA nanotechnology can be used to construct a variety of nanostructures with precisely controllable size, shape, and surface chemistry, which can be appreciated in the delivery process. In this review, different approaches that are currently used for the construction of DNA nanostructures are reported. Further, the utilization of these DNA nanostructures with the well-defined parameters for the precise control in drug delivery and gene therapy is discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Direct torque control of six-phase induction motors using three-phase matrix converter

    International Nuclear Information System (INIS)

    Talaeizadeh, V.; Kianinezhad, R.; Seyfossadat, S.G.; Shayanfar, H.A.

    2010-01-01

    This paper presents a new direct torque control (DTC) method for six-phase induction motor (SPIM). In the proposed method, direct torque and flux control are applied to the SPIM using matrix converter with the conventional three-phase source as its input. The new DTC scheme for SPIM benefits the advantages of both DTC and matrix converter, such as unity power factor and absence of dc-link. The simulation results show the effectiveness of the proposed method in both dynamic and steady state response.

  6. INTERPOLYELECTROLYTE COMPLEXES AS PROSPECTIVE CARRIERS FOR CONTROLLED DRUG DELIVERY

    OpenAIRE

    Kaur Jasmeet; Harikumar S.L.; Kaur Amanpreet

    2012-01-01

    In the current scenario, polymers as carriers have revolutionized the drug delivery system. A more successful approach, to exploit the different properties of polymers in a solitary system is the complexation of polymers to form polyelectrolyte complexes. These complexes circumvent the use of chemical crosslinking agents, thereby reducing the risk of toxicity. The complex formed is generally applied in different dosage forms for the formulation of stable aggregated macromolecules. There are t...

  7. Nanotechnology: from In Vivo Imaging System to Controlled Drug Delivery.

    Science.gov (United States)

    Mir, Maria; Ishtiaq, Saba; Rabia, Samreen; Khatoon, Maryam; Zeb, Ahmad; Khan, Gul Majid; Ur Rehman, Asim; Ud Din, Fakhar

    2017-08-17

    Science and technology have always been the vitals of human's struggle, utilized exclusively for the development of novel tools and products, ranging from micro- to nanosize. Nanotechnology has gained significant attention due to its extensive applications in biomedicine, particularly related to bio imaging and drug delivery. Various nanodevices and nanomaterials have been developed for the diagnosis and treatment of different diseases. Herein, we have described two primary aspects of the nanomedicine, i.e., in vivo imaging and drug delivery, highlighting the recent advancements and future explorations. Tremendous advancements in the nanotechnology tools for the imaging, particularly of the cancer cells, have recently been observed. Nanoparticles offer a suitable medium to carryout molecular level modifications including the site-specific imaging and targeting. Invention of radionuclides, quantum dots, magnetic nanoparticles, and carbon nanotubes and use of gold nanoparticles in biosensors have revolutionized the field of imaging, resulting in easy understanding of the pathophysiology of disease, improved ability to diagnose and enhanced therapeutic delivery. This high specificity and selectivity of the nanomedicine is important, and thus, the recent advancements in this field need to be understood for a better today and a more prosperous future.

  8. Nanotechnology: from In Vivo Imaging System to Controlled Drug Delivery

    Science.gov (United States)

    Mir, Maria; Ishtiaq, Saba; Rabia, Samreen; Khatoon, Maryam; Zeb, Ahmad; Khan, Gul Majid; ur Rehman, Asim; ud Din, Fakhar

    2017-08-01

    Science and technology have always been the vitals of human's struggle, utilized exclusively for the development of novel tools and products, ranging from micro- to nanosize. Nanotechnology has gained significant attention due to its extensive applications in biomedicine, particularly related to bio imaging and drug delivery. Various nanodevices and nanomaterials have been developed for the diagnosis and treatment of different diseases. Herein, we have described two primary aspects of the nanomedicine, i.e., in vivo imaging and drug delivery, highlighting the recent advancements and future explorations. Tremendous advancements in the nanotechnology tools for the imaging, particularly of the cancer cells, have recently been observed. Nanoparticles offer a suitable medium to carryout molecular level modifications including the site-specific imaging and targeting. Invention of radionuclides, quantum dots, magnetic nanoparticles, and carbon nanotubes and use of gold nanoparticles in biosensors have revolutionized the field of imaging, resulting in easy understanding of the pathophysiology of disease, improved ability to diagnose and enhanced therapeutic delivery. This high specificity and selectivity of the nanomedicine is important, and thus, the recent advancements in this field need to be understood for a better today and a more prosperous future.

  9. Electrically responsive microreservoires for controllable delivery of dexamethasone in bone tissue engineering

    Science.gov (United States)

    Paun, Irina Alexandra; Zamfirescu, Marian; Luculescu, Catalin Romeo; Acasandrei, Adriana Maria; Mustaciosu, Cosmin Catalin; Mihailescu, Mona; Dinescu, Maria

    2017-01-01

    A major concern in orthopedic implants is to decrease the chronic inflammation using specific drug therapies. The newest strategies rely on the controlled delivery of antiinflammatory drugs from carrier biointerfaces designed in the shape of 3D architectures. We report on electrically responsive microreservoires (ERRs) acting as microcontainers for antiinflammatory drugs, as potential biointerfaces in orthopedic implants. The ERRs consist in arrays of vertical microtubes produced by laser direct writing using two photon polymerization effects (2PP_LDW) of a commercially available photoresist, IP-L780. A polypyrrole (conductive)/dexamethasone (drug model) (PPy/Dex) mixture was loaded into the ERRs via a simple immersion process. Then, the ERRs were sealed with a poly(lactic-co-glycolic acid)(PLGA) layer by Matrix Assisted Pulsed Laser Evaporation. ERRs stimulation using voltage cycles between -1 V and +1 V, applied at specific time intervals, at a scan rate of 0.1 V s-1, enabled to control the Dex release. The release time scales were between 150 and 275 h, while the concentrations of Dex released were between 450-460 nM after three applied voltage cycles, for different microreservoires dimensions. The proposed approach was validated in osteoblast-like MG-63 cell cultures. Cell viability and adhesion assays showed that the Dex-loaded ERRs sustained the cells growth and preserved their characteristic polygonal shape. Importantly, for the electrically-stimulated Dex release, the level of the alkaline phosphatase activity increased twice, the osteogenic differentiation surpassed by 1.6 times and the relative level of osteocalcin gene expression was 2.2 times higher as compared with the unstimulated drug release. Overall, the ERRs were able to accelerate the cells osteogenic differentiation via electrically controlled release of Dex.

  10. A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

    OpenAIRE

    Naggar H. Saad; Ahmed A. El-Sattar; Mohamed I. Marei

    2016-01-01

    The main challenges of wind energy conversion systems (WECS) are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG) based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG curren...

  11. Oral controlled release drug delivery system and Characterization of oral tablets; A review

    OpenAIRE

    Muhammad Zaman; Junaid Qureshi; Hira Ejaz; Rai Muhammad Sarfraz; Hafeez ullah Khan; Fazal Rehman Sajid; Muhammad Shafiq ur Rehman

    2016-01-01

    Oral route of drug administration is considered as the safest and easiest route of drug administration. Control release drug delivery system is the emerging trend in the pharmaceuticals and the oral route is most suitable for such kind of drug delivery system. Oral route is more convenient for It all age group including both pediatric and geriatrics. There are various systems which are adopted to deliver drug in a controlled manner to different target sites through oral route. It includes dif...

  12. A DNA nanocapsule with aptamer-controlled open-closure function for targeted delivery

    DEFF Research Database (Denmark)

    Bentin, Thomas

    2012-01-01

    A DNA capsule fitted with aptamer controlled target sensing has been "woven" using a 7308-base single-stranded DNA "thread" and 196 staple oligonucleotides. The capsule enables logic-gated molecular cargo delivery to targeted cell surfaces.......A DNA capsule fitted with aptamer controlled target sensing has been "woven" using a 7308-base single-stranded DNA "thread" and 196 staple oligonucleotides. The capsule enables logic-gated molecular cargo delivery to targeted cell surfaces....

  13. Extracellular matrix and growth factor engineering for controlled angiogenesis in regenerative medicine

    Directory of Open Access Journals (Sweden)

    Mikaël M Martino

    2015-04-01

    Full Text Available Blood vessel growth plays a key role in regenerative medicine, both to restore blood supply to ischemic tissues and to ensure rapid vascularization of clinical-size tissue-engineered grafts. For example, vascular endothelial growth factor (VEGF is the master regulator of physiological blood vessel growth and is one of the main molecular targets of therapeutic angiogenesis approaches. However, angiogenesis is a complex process and there is a need to develop rational therapeutic strategies based on a firm understanding of basic vascular biology principles, as evidenced by the disappointing results of initial clinical trials of angiogenic factor delivery. In particular, the spatial localization of angiogenic signals in the extracellular matrix is crucial to ensure the proper assembly and maturation of new vascular structures. Here we discuss the therapeutic implications of matrix interactions of angiogenic factors, with a special emphasis on VEGF, as well as provide an overview of current approaches, based on protein and biomaterial engineering that mimic the regulatory functions of extracellular matrix to optimize the signaling microenvironment of vascular growth factors.

  14. Solid lipid nanoparticles for oral drug delivery: chitosan coating improves stability, controlled delivery, mucoadhesion and cellular uptake.

    Science.gov (United States)

    Luo, Yangchao; Teng, Zi; Li, Ying; Wang, Qin

    2015-05-20

    The poor stability of solid lipid nanoparticles (SLN) under acidic condition resulted in large aggregation in gastric environment, limiting their application as oral delivery systems. In this study, a series of SLN was prepared to investigate the effects of surfactant/cosurfactant and chitosan coating on their physicochemical properties as well as cellular uptake. SLN was prepared from Compritol 888 ATO using a low-energy method combining the solvent-diffusion and hot homogenization technique. Poloxamer 188 and polyethylene glycol (PEG) were effective emulsifiers to produce SLN with better physicochemical properties than SLN control. Chitosan-coated SLN exhibited the best stability under acidic condition by forming a thick layer around the lipid core, as clearly observed by transmission electron microscope. The intermolecular interactions in different formulations were monitored by Fourier transform infrared spectroscopy. Chitosan coating also significantly improved the mucoadhesive property of SLN as determined by Quartz Crystal Microbalance. In vitro drug delivery assays, cytotoxicity, and cellular uptake of SLN were studied by incorporating coumarin 6 as a fluorescence probe. Overall, chitosan-coated SLN was superior to other formulations and held promising features for its application as a potential oral drug delivery system for hydrophobic drugs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. COMPUTATIONAL EXPERIENCE IN SOLVING LARGE LINEAR MATRIX EQUATIONS FOR AUTOMATIC CONTROL

    Directory of Open Access Journals (Sweden)

    Vasile Sima

    2004-12-01

    Full Text Available State-of-the-art, uni-processor linear matrix equation solvers for automatic control computations are investigated and compared for various problem sizes. Generalpurpose SLICOT solvers are the most efficient ones for small-size problems, but they cannot compete for larger problems with specialized solvers designed for certain problem classes.

  16. A New Real Time Lyapunov Based Controller for Power Quality Improvement in Unified Power Flow Controllers Using Direct Matrix Converters

    Directory of Open Access Journals (Sweden)

    Joaquim Monteiro

    2017-06-01

    Full Text Available This paper proposes a Direct Matrix Converter operating as a Unified Power Flow Controller (DMC-UPFC with an advanced control method for UPFC, based on the Lyapunov direct method, presenting good results in power quality assessment. This control method is used for real-time calculation of the appropriate matrix switching state, determining which switching state should be applied in the following sampling period. The control strategy takes into account active and reactive power flow references to choose the vector converter closest to the optimum. Theoretical principles for this new real-time vector modulation and control applied to the DMC-UPFC with input filter are established. The method needs DMC-UPFC dynamic equations to be solved just once in each control cycle, to find the required optimum vector, in contrast to similar control methods that need 27 vector estimations per control cycle. The designed controller’s performance was evaluated using Matlab/Simulink software. Controllers were also implemented using a digital signal processing (DSP system and matrix hardware. Simulation and experimental results show decoupled transmission line active (P and reactive (Q power control with zero theoretical error tracking and fast response. Output currents and voltages show small ripple and low harmonic content.

  17. A unified approach to fixed-order controller design via linear matrix inequalities

    Directory of Open Access Journals (Sweden)

    T. Iwasaki

    1995-01-01

    Full Text Available We consider the design of fixed-order (or low-order linear controllers which meet certain performance and/or robustness specifications. The following three problems are considered; covariance control as a nominal performance problem,-stabilization as a robust stabilization problem, and robust L∞ control problem as a robust performance problem. All three control problems are converted to a single linear algebra problem of solving a linear matrix inequality (LMI of the type BGC+(BGCT+Q<0 for the unknown matrix G. Thus this paper addresses the fixed-order controller design problem in a unified way. Necessary and sufficient conditions for the existence of a fixed-order controller which satisfies the design specifications for each problem are derived, and an explicit controller formula is given. In any case, the resulting problem is shown to be a search for a (structured positive definite matrix X such that X∈1 and X−1∈2 where 1 and 2 are convex sets defined by LMIs. Computational aspects of the nonconvex LMI problem are discussed.

  18. A unified approach to fixed-order controller design via linear matrix inequalities

    Directory of Open Access Journals (Sweden)

    Iwasaki T.

    1995-01-01

    Full Text Available We consider the design of fixed-order (or low-order linear controllers which meet certain performance and/or robustness specifications. The following three problems are considered; covariance control as a nominal performance problem, 𝒬 -stabilization as a robust stabilization problem, and robust L ∞ control problem as a robust performance problem. All three control problems are converted to a single linear algebra problem of solving a linear matrix inequality (LMI of the type B G C + ( B G C T + Q < 0 for the unknown matrix G . Thus this paper addresses the fixed-order controller design problem in a unified way. Necessary and sufficient conditions for the existence of a fixed-order controller which satisfies the design specifications for each problem are derived, and an explicit controller formula is given. In any case, the resulting problem is shown to be a search for a (structured positive definite matrix X such that X ∈ 𝒞 1 and X − 1 ∈ 𝒞 2 where 𝒞 1 and 𝒞 2 are convex sets defined by LMIs. Computational aspects of the nonconvex LMI problem are discussed.

  19. Performance Improvement of Sensorless Vector Control for Matrix Converter Drives Using PQR Transformation

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2005-01-01

    using PQR transformation and compensated using a reference current control scheme. To eliminate the input current distortion due to the input voltage unbalance, a simple method using PQR transformation is also proposed. The proposed compensation method is applied for high performance induction motor......This paper presents a new method to improve sensorless performance of matrix converter drives using PQR power transformation. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled...

  20. Independent control of matrix adhesiveness and stiffness within a 3D self-assembling peptide hydrogel.

    Science.gov (United States)

    Hogrebe, Nathaniel J; Reinhardt, James W; Tram, Nguyen K; Debski, Anna C; Agarwal, Gunjan; Reilly, Matthew A; Gooch, Keith J

    2018-04-01

    A cell's insoluble microenvironment has increasingly been shown to exert influence on its function. In particular, matrix stiffness and adhesiveness strongly impact behaviors such as cell spreading and differentiation, but materials that allow for independent control of these parameters within a fibrous, stromal-like microenvironment are very limited. In the current work, we devise a self-assembling peptide (SAP) system that facilitates user-friendly control of matrix stiffness and RGD (Arg-Gly-Asp) concentration within a hydrogel possessing a microarchitecture similar to stromal extracellular matrix. In this system, the RGD-modified SAP sequence KFE-RGD and the scrambled sequence KFE-RDG can be directly swapped for one another to change RGD concentration at a given matrix stiffness and total peptide concentration. Stiffness is controlled by altering total peptide concentration, and the unmodified base peptide KFE-8 can be included to further increase this stiffness range due to its higher modulus. With this tunable system, we demonstrate that human mesenchymal stem cell morphology and differentiation are influenced by both gel stiffness and the presence of functional cell binding sites in 3D culture. Specifically, cells 24 hours after encapsulation were only able to spread out in stiffer matrices containing KFE-RGD. Upon addition of soluble adipogenic factors, soft gels facilitated the greatest adipogenesis as determined by the presence of lipid vacuoles and PPARγ-2 expression, while increasing KFE-RGD concentration at a given stiffness had a negative effect on adipogenesis. This three-component hydrogel system thus allows for systematic investigation of matrix stiffness and RGD concentration on cell behavior within a fibrous, three-dimensional matrix. Physical cues from a cell's surrounding environment-such as the density of cell binding sites and the stiffness of the surrounding material-are increasingly being recognized as key regulators of cell function

  1. A Predictive-Control-Based Over-Modulation Method for Conventional Matrix Converters

    DEFF Research Database (Denmark)

    Zhang, Guanguan; Yang, Jian; Sun, Yao

    2018-01-01

    to further enhance the system performance promptly. This method has advantages like the maximum voltage transfer ratio can reach 0.987 in the experiments; the total harmonic distortion of the input and output current are reduced, and the losses in the matrix converter are decreased. Moreover, the specific......To increase the voltage transfer ratio of the matrix converter and improve the input/output current performance simultaneously, an over-modulation method based on predictive control is proposed in this paper, where the weighting factor is selected by an automatic adjusting mechanism, which is able...

  2. Electrically responsive microreservoires for controllable delivery of dexamethasone in bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Paun, Irina Alexandra, E-mail: irina.paun@physics.pub.ro [Faculty of Applied Sciences, University Politehnica of Bucharest, RO-060042 (Romania); National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest RO-077125 (Romania); Zamfirescu, Marian [National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest RO-077125 (Romania); Luculescu, Catalin Romeo, E-mail: catalin.luculescu@inflpr.ro [National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest RO-077125 (Romania); Acasandrei, Adriana Maria; Mustaciosu, Cosmin Catalin [Horia Hulubei National Institute for Physics and Nuclear Engineering IFIN-HH, Magurele, Bucharest RO-077125 (Romania); Mihailescu, Mona [Faculty of Applied Sciences, University Politehnica of Bucharest, RO-060042 (Romania); Dinescu, Maria, E-mail: dinescum@nipne.ro [National Institute for Laser, Plasma and Radiation Physics, Magurele, Bucharest RO-077125 (Romania)

    2017-01-15

    Highlights: • Electrically-responsive microreservoires (ERRs) for controlled release of Dex. • ERRs made of microtubes produced by two photon polymerization of IP-L780 photoresist. • Microtubes loaded with PPy/Dex mixture and sealed with a thin PLGA layer. • Kinetics of Dex release controlled by electrical stimulation of the ERRs. • Controlled Dex release accelerates the cells osteogenic differentiation. - Abstract: A major concern in orthopedic implants is to decrease the chronic inflammation using specific drug therapies. The newest strategies rely on the controlled delivery of antiinflammatory drugs from carrier biointerfaces designed in the shape of 3D architectures. We report on electrically responsive microreservoires (ERRs) acting as microcontainers for antiinflammatory drugs, as potential biointerfaces in orthopedic implants. The ERRs consist in arrays of vertical microtubes produced by laser direct writing using two photon polymerization effects (2PP-LDW) of a commercially available photoresist, IP-L780. A polypyrrole (conductive)/dexamethasone (drug model) (PPy/Dex) mixture was loaded into the ERRs via a simple immersion process. Then, the ERRs were sealed with a poly(lactic-co-glycolic acid)(PLGA) layer by Matrix Assisted Pulsed Laser Evaporation. ERRs stimulation using voltage cycles between −1 V and +1 V, applied at specific time intervals, at a scan rate of 0.1 V s{sup −1}, enabled to control the Dex release. The release time scales were between 150 and 275 h, while the concentrations of Dex released were between 450–460 nM after three applied voltage cycles, for different microreservoires dimensions. The proposed approach was validated in osteoblast-like MG-63 cell cultures. Cell viability and adhesion assays showed that the Dex-loaded ERRs sustained the cells growth and preserved their characteristic polygonal shape. Importantly, for the electrically-stimulated Dex release, the level of the alkaline phosphatase activity increased

  3. Electrically responsive microreservoires for controllable delivery of dexamethasone in bone tissue engineering

    International Nuclear Information System (INIS)

    Paun, Irina Alexandra; Zamfirescu, Marian; Luculescu, Catalin Romeo; Acasandrei, Adriana Maria; Mustaciosu, Cosmin Catalin; Mihailescu, Mona; Dinescu, Maria

    2017-01-01

    Highlights: • Electrically-responsive microreservoires (ERRs) for controlled release of Dex. • ERRs made of microtubes produced by two photon polymerization of IP-L780 photoresist. • Microtubes loaded with PPy/Dex mixture and sealed with a thin PLGA layer. • Kinetics of Dex release controlled by electrical stimulation of the ERRs. • Controlled Dex release accelerates the cells osteogenic differentiation. - Abstract: A major concern in orthopedic implants is to decrease the chronic inflammation using specific drug therapies. The newest strategies rely on the controlled delivery of antiinflammatory drugs from carrier biointerfaces designed in the shape of 3D architectures. We report on electrically responsive microreservoires (ERRs) acting as microcontainers for antiinflammatory drugs, as potential biointerfaces in orthopedic implants. The ERRs consist in arrays of vertical microtubes produced by laser direct writing using two photon polymerization effects (2PP-LDW) of a commercially available photoresist, IP-L780. A polypyrrole (conductive)/dexamethasone (drug model) (PPy/Dex) mixture was loaded into the ERRs via a simple immersion process. Then, the ERRs were sealed with a poly(lactic-co-glycolic acid)(PLGA) layer by Matrix Assisted Pulsed Laser Evaporation. ERRs stimulation using voltage cycles between −1 V and +1 V, applied at specific time intervals, at a scan rate of 0.1 V s −1 , enabled to control the Dex release. The release time scales were between 150 and 275 h, while the concentrations of Dex released were between 450–460 nM after three applied voltage cycles, for different microreservoires dimensions. The proposed approach was validated in osteoblast-like MG-63 cell cultures. Cell viability and adhesion assays showed that the Dex-loaded ERRs sustained the cells growth and preserved their characteristic polygonal shape. Importantly, for the electrically-stimulated Dex release, the level of the alkaline phosphatase activity increased twice

  4. Distinct presynaptic control of dopamine release in striosomal and matrix areas of the cat caudate nucleus

    International Nuclear Information System (INIS)

    Kemel, M.L.; Desban, M.; Glowinski, J.; Gauchy, C.

    1989-01-01

    By use of a sensitive in vitro microsuperfusion method, the cholinergic presynaptic control of dopamine release was investigated in a prominent striosome (areas poor in acetylcholinesterase activity) located within the core of cat caudate nucleus and also in adjacent matrix area. The spontaneous release of [ 3 H]dopamine continuously synthesized from [ 3 H]tyrosine in the matrix area was found to be twice that in the striosomal area; the spontaneous and potassium-evoked releases of [ 3 H]dopamine were calcium-dependent in both compartments. With 10 -6 M tetrodotoxin, 5 x 10 -5 M acetylcholine stimulated [ 3 H]dopamine release in both striosomal and matrix areas, effects completely antagonized by atropine, thus showing the involvement of muscarinic receptors located on dopaminergic nerve terminals. Experiments without tetrodotoxin revealed a more complex regulation of dopamine release in the matrix: (i) in contrast to results seen in the striosome, acetylcholine induced only a transient stimulatory effect on matrix dopamine release. (ii) Although 10 -6 M atropine completely abolished the cholinergic stimulatory effect on [ 3 H]dopamine release in striosomal area, delayed and prolonged stimulation of [ 3 H] dopamine release was seen with atropine in the matrix. The latter effect was completely abolished by the nicotinic antagonist pempidine. Therefore, in the matrix, in addition to its direct (tetrodotoxin-insensitive) facilitatory action on [ 3 H]dopamine release, acetylcholine exerts two indirect (tetrodotoxin-sensitive) opposing effects: an inhibition and a stimulation of [ 3 H]dopamine release mediated by muscarinic and nicotinic receptors, respectively

  5. Web- vs. telehealth-based delivery of cognitive behavioral therapy for insomnia: a randomized controlled trial.

    Science.gov (United States)

    Holmqvist, M; Vincent, N; Walsh, K

    2014-02-01

    The purpose of our study was to evaluate and compare two methods of service delivery (web-based and telehealth-based) for chronic insomnia with regard to patient preference, clinical effectiveness, and patient satisfaction. Our study was a randomized controlled trial with manualized telehealth- and web-based delivery conditions (nonblinded). The sample comprised 73 adults with chronic insomnia. Participants received web-based delivery from their homes or telehealth-based delivery from a nearby clinic. Both interventions consisted of identical psychoeducation, sleep hygiene and stimulus control instruction, sleep restriction treatment, relaxation training, cognitive therapy, mindfulness meditation, and medication-tapering assistance. Using a linear mixed model analysis, results showed that both delivery methods produced equivalent changes in insomnia severity, with large effect sizes. Attendance patterns favored telehealth, whereas homework adherence and preference data favored web-based delivery. Web- and telehealth-based delivery are both helpful in treating chronic insomnia in rural-dwelling adults. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Mode of Delivery in Drug-Dependent Pregnant Women: A Case Control Study.

    Science.gov (United States)

    Neves, Ana Raquel; Neves, Fabiane; Santos Silva, Isabel; Almeida, Maria do Céu; Monteiro, Pitorra

    2017-01-01

    Objective . To determine the contribution of drug use during pregnancy to the route of delivery. Methods . A case-control study was conducted at a hospital in Coimbra, Portugal, between 2001 and 2014. Drug-dependent pregnant women ( n = 236) were compared with a control group of low risk women ( n = 228) in terms of maternal characteristics, obstetric history, pregnancy complications, and labor details. Factors that influenced the mode of delivery were determined. Statistical analysis was performed with SPSS v. 23.0 (IBM Corp.). p values Drug-dependent women presented a lower rate of cesarean delivery (18.2 versus 28.9%, p = 0.006). After adjusting for the factors that were significantly related to the mode of delivery, drug dependency influenced the rate of cesarean section ( β = 0.567; 95% CI = 0.328-0.980). Within the drug-dependent group, the mode of delivery was significantly related to previous cesarean or vaginal delivery ( p = 0.008 and p drug, route of administration, or substitution maintenance therapy. Conclusions . The drug-dependent group presented a significantly higher rate of vaginal delivery. However, this was not associated with the behavioral factors analyzed. We hypothesize that other social and psychological factors might explain this difference.

  7. Mode of Delivery in Drug-Dependent Pregnant Women: A Case Control Study

    Directory of Open Access Journals (Sweden)

    Ana Raquel Neves

    2017-01-01

    Full Text Available Objective. To determine the contribution of drug use during pregnancy to the route of delivery. Methods. A case-control study was conducted at a hospital in Coimbra, Portugal, between 2001 and 2014. Drug-dependent pregnant women (n=236 were compared with a control group of low risk women (n=228 in terms of maternal characteristics, obstetric history, pregnancy complications, and labor details. Factors that influenced the mode of delivery were determined. Statistical analysis was performed with SPSS v. 23.0 (IBM Corp.. p values < 0.05 were considered statistically significant. Results. Drug-dependent women presented a lower rate of cesarean delivery (18.2 versus 28.9%, p=0.006. After adjusting for the factors that were significantly related to the mode of delivery, drug dependency influenced the rate of cesarean section (β=0.567; 95% CI = 0.328–0.980. Within the drug-dependent group, the mode of delivery was significantly related to previous cesarean or vaginal delivery (p=0.008 and p<0.001, resp. and fetal presentation (p<0.001, but not with the type of drug, route of administration, or substitution maintenance therapy. Conclusions. The drug-dependent group presented a significantly higher rate of vaginal delivery. However, this was not associated with the behavioral factors analyzed. We hypothesize that other social and psychological factors might explain this difference.

  8. Design of matrix irradiation system for external tissue phototherapy with temperature control

    Science.gov (United States)

    López S., F. Yonadab; Stolik Isakina, Suren; de La Rosa Vázquez, José Manuel

    2013-11-01

    This paper presents the design and development of a matrix irradiation system for studies and application of dermatological phototherapies with temperature control. The developed system has a power control to irradiate the target tissue with an adequate power density. Also, the irradiation time it is automated. Temperature infrared sensor is used in the irradiated sample to control the temperature. The temperature control allows the study of photodynamic therapy effects in synergy with the thermotherapy effects in the treatment of different diseases in external tissue.

  9. Magnetic nanomaterials for hyperthermia-based therapy and controlled drug delivery.

    Science.gov (United States)

    Kumar, Challa S S R; Mohammad, Faruq

    2011-08-14

    Previous attempts to review the literature on magnetic nanomaterials for hyperthermia-based therapy focused primarily on magnetic fluid hyperthermia (MFH) using mono metallic/metal oxide nanoparticles. The term "hyperthermia" in the literature was also confined only to include use of heat for therapeutic applications. Recently, there have been a number of publications demonstrating magnetic nanoparticle-based hyperthermia to generate local heat resulting in the release of drugs either bound to the magnetic nanoparticle or encapsulated within polymeric matrices. In this review article, we present a case for broadening the meaning of the term "hyperthermia" by including thermotherapy as well as magnetically modulated controlled drug delivery. We provide a classification for controlled drug delivery using hyperthermia: Hyperthermia-based controlled drug delivery through bond breaking (DBB) and hyperthermia-based controlled drug delivery through enhanced permeability (DEP). The review also covers, for the first time, core-shell type magnetic nanomaterials, especially nanoshells prepared using layer-by-layer self-assembly, for the application of hyperthermia-based therapy and controlled drug delivery. The highlight of the review article is to portray potential opportunities for the combination of hyperthermia-based therapy and controlled drug release paradigms--towards successful application in personalized medicine. Copyright © 2011 Elsevier B.V. All rights reserved.

  10. Magnetic Nanomaterials for Hyperthermia-based Therapy and Controlled Drug Delivery

    Science.gov (United States)

    Kumar, Challa S. S. R.; Mohammad, Faruq

    2011-01-01

    Previous attempts to review the literature on magnetic nanomaterials for hyperthermia-based therapy focused primarily on magnetic fluid hyperthermia (MFH) using mono metallic/metal oxide nanoparticles. The term “Hyperthermia” in the literature was also confined only to include use of heat for therapeutic applications. Recently, there have been a number of publications demonstrating magnetic nanoparticle-based hyperthermia to generate local heat resulting in the release of drugs either bound to the magnetic nanoparticle or encapsulated within polymeric matrices. In this review article, we present a case for broadening the meaning of the term “hyperthermia” by including thermotherapy as well as magnetically modulated controlled drug delivery. We provide a classification for controlled drug delivery using hyperthermia: Hyperthermia-based controlled Drug delivery through Bond Breaking (DBB) and Hyperthermia-based controlled Drug delivery through Enhanced Permeability (DEP). The review also covers, for the first time, core-shell type magnetic nanomaterials, especially nanoshells prepared using layer-by-layer self-assembly, for the application of hyperthermia-based therapy and controlled drug delivery. The highlight of the review article is to portray potential opportunities in the combination of hyperthermia-based therapy and controlled drug release paradigms for successful application in personalized medicine. PMID:21447363

  11. Active compensation of wavefront aberrations by controllable heating of lens with electric film heater matrix.

    Science.gov (United States)

    Chen, Hua; Hou, Lv; Zhou, Xinglin

    2016-08-20

    We present a new apparatus for active compensation of wavefront aberrations by controllable heating of a lens using a film heater matrix. The annular electric film heater matrix, comprising 24 individual heaters, is attached to the periphery of a lens. Utilizing the linear superposition, and wavefront change proportional to the heating energy properties induced by heating, a controllable wavefront can be defined by solving a linear function. The two properties of wavefront change of a lens have been confirmed through a specially designed experiment. The feasibility of the compensation method is validated by compensating the wavefront of a plate lens. The results show that the wavefront of the lens changes from 12.52 to 2.95 nm rms after compensation. With a more precise electric controlling board, better results could be achieved.

  12. Nanohybrid Electro-Coatings Toward Therapeutic Implants with Controlled Drug Delivery Potential for Bone Regeneration.

    Science.gov (United States)

    Patel, Kapil D; Singh, Rajendra K; Mahapatra, Chinmaya; Lee, Eun-Jung; Kim, Hae-Won

    2016-10-01

    Coatings of metallic implants facilitate a new bioactive interface that favors osteogenic responses and bone formation. Providing a therapeutic capacity to the coatings, involving with a sustainable and controllable delivery of drug molecules, significantly improves the bone regenerative potential. Here we design a novel nanocomposite coating, made of mesoporous silica-shelled hydroxyapatite (MS-HA) nanoparticles and chitosan (Chi), incorporating osteogenic drug dexamethasone phosphate (Dex(P)) within the MS-HA, by the process of an electrophoretic deposition (EPD). MS-HA, produced by a sol–gel reaction of silica onto an HA nanorod, exhibited mono-dispersed core–shell nanoparticles with a size of ∼40 nm and a shell thickness of ∼25 nm. The highly mesoporous structure enabled an effective loading of Dex(P) onto the nanocarriers, showing a loading capacity as high as 15% by weight. The Dex(P) loaded MS-HA were homogenized with Chi in acidic ethanol/water to allow for the EPD process. Nanocomposite coatings were produced well, forming thicknesses a few micrometers largely tunable with EPD parameters and exhibiting MS-HA nanoparticles evenly distributed within Chi matrix. While Dex(P) release from the bare MS-HA nanocarrier was very abrupt, showing a complete release within 24 h, the Dex(P) release from the nanocomposite coatings profiled a highly sustainable pattern over a month. Rat mesenchymal stem cells cultured on the Dex(P)-releasing coatings were substantially stimulated to an osteoblastic lineage, presenting enhanced alkaline phosphate activity and higher levels of osteogenic genes, with respect to coatings free of Dex(P). An indirect culture test also confirmed the long-term release effects of Dex(P) from the coatings over 4 weeks. The currently-developed nanocomposite EPD coatings, with a capacity to load osteogenic drug at large quantity and to deliver for a long-term period, are considered as a promising therapeutic coating platform for metallic

  13. Design Of Multivariable Fractional Order Pid Controller Using Covariance Matrix Adaptation Evolution Strategy

    Directory of Open Access Journals (Sweden)

    Sivananaithaperumal Sudalaiandi

    2014-06-01

    Full Text Available This paper presents an automatic tuning of multivariable Fractional-Order Proportional, Integral and Derivative controller (FO-PID parameters using Covariance Matrix Adaptation Evolution Strategy (CMAES algorithm. Decoupled multivariable FO-PI and FO-PID controller structures are considered. Oustaloup integer order approximation is used for the fractional integrals and derivatives. For validation, two Multi-Input Multi- Output (MIMO distillation columns described byWood and Berry and Ogunnaike and Ray are considered for the design of multivariable FO-PID controller. Optimal FO-PID controller is designed by minimizing Integral Absolute Error (IAE as objective function. The results of previously reported PI/PID controller are considered for comparison purposes. Simulation results reveal that the performance of FOPI and FO-PID controller is better than integer order PI/PID controller in terms of IAE. Also, CMAES algorithm is suitable for the design of FO-PI / FO-PID controller.

  14. Clinical translation of controlled protein delivery systems for tissue engineering.

    Science.gov (United States)

    Spiller, Kara L; Vunjak-Novakovic, Gordana

    2015-04-01

    Strategies that utilize controlled release of drugs and proteins for tissue engineering have enormous potential to regenerate damaged organs and tissues. The multiple advantages of controlled release strategies merit overcoming the significant challenges to translation, including high costs and long, difficult regulatory pathways. This review highlights the potential of controlled release of proteins for tissue engineering and regenerative medicine. We specifically discuss treatment modalities that have reached preclinical and clinical trials, with emphasis on controlled release systems for bone tissue engineering, the most advanced application with several products already in clinic. Possible strategies to address translational and regulatory concerns are also discussed.

  15. Monodisperse, Uniformly-Shaped Particles for Controlled Respiratory Vaccine Delivery

    Science.gov (United States)

    Fromen, Catherine Ann

    The majority of the world's most infectious diseases occur at the air-tissue interface called the mucosa, including HIV/AIDS, tuberculosis, measles, and bacterial or viral gut and respiratory infections. Despite this, vaccines have generally been developed for the systemic immune system and fail to provide protection at the mucosal site. Vaccine delivery directly to the lung mucosa could provide superior lung protection for many infectious diseases, such as TB or influenza, as well as systemic and therapeutic vaccines for diseases such as Dengue fever, asthma, or cancer. Specifically, precision engineered biomaterials are believed to offer tremendous opportunities for a new generation of vaccines. The goal of this approach is to leverage naturally occurring processes of the immune system to produce memory responses capable of rapidly destroy virulent pathogens without harmful exposure. Considerable knowledge of biomaterial properties and their interaction with the immune system of the lung is required for successful translation. The overall goal of this work was to fabricate and characterize nano- and microparticles using the Particle Replication In Non-wetting Templates (PRINT) fabrication technique and optimize them as pulmonary vaccine carriers. (Abstract shortened by ProQuest.).

  16. Polylactic acid (PLA) controlled delivery carriers for biomedical applications.

    Science.gov (United States)

    Tyler, Betty; Gullotti, David; Mangraviti, Antonella; Utsuki, Tadanobu; Brem, Henry

    2016-12-15

    Polylactic acid (PLA) and its copolymers have a long history of safety in humans and an extensive range of applications. PLA is biocompatible, biodegradable by hydrolysis and enzymatic activity, has a large range of mechanical and physical properties that can be engineered appropriately to suit multiple applications, and has low immunogenicity. Formulations containing PLA have also been Food and Drug Administration (FDA)-approved for multiple applications making PLA suitable for expedited clinical translatability. These biomaterials can be fashioned into sutures, scaffolds, cell carriers, drug delivery systems, and a myriad of fabrications. PLA has been the focus of a multitude of preclinical and clinical testing. Three-dimensional printing has expanded the possibilities of biomedical engineering and has enabled the fabrication of a myriad of platforms for an extensive variety of applications. PLA has been widely used as temporary extracellular matrices in tissue engineering. At the other end of the spectrum, PLA's application as drug-loaded nanoparticle drug carriers, such as liposomes, polymeric nanoparticles, dendrimers, and micelles, can encapsulate otherwise toxic hydrophobic anti-tumor drugs and evade systemic toxicities. The clinical translation of these technologies from preclinical experimental settings is an ever-evolving field with incremental advancements. In this review, some of the biomedical applications of PLA and its copolymers are highlighted and briefly summarized. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Biomaterial-based drug delivery systems for the controlled release of neurotrophic factors

    International Nuclear Information System (INIS)

    Mohtaram, Nima Khadem; Montgomery, Amy; Willerth, Stephanie M

    2013-01-01

    This review highlights recent work on the use of biomaterial-based drug delivery systems to control the release of neurotrophic factors as a potential strategy for the treatment of neurological disorders. Examples of neurotrophic factors include the nerve growth factor, the glial cell line-derived neurotrophic factor, the brain-derived neurotrophic factor and neurotrophin-3. In particular, this review focuses on two methods of drug delivery: affinity-based and reservoir-based systems. We review the advantages and challenges associated with both types of drug delivery system and how these systems can be applied to neurological diseases and disorders. While a limited number of affinity-based delivery systems have been developed for the delivery of neurotrophic factors, we also examine the broad spectrum of reservoir-based delivery systems, including microspheres, electrospun nanofibers, hydrogels and combinations of these systems. Finally, conclusions are drawn about the current state of such drug delivery systems as applied to neural tissue engineering along with some thoughts on the future direction of the field. (topical review)

  18. Closed-loop controlled noninvasive ultrasonic glucose sensing and insulin delivery

    Science.gov (United States)

    Park, Eun-Joo; Werner, Jacob; Jaiswal, Devina; Smith, Nadine Barrie

    2010-03-01

    To prevent complications in diabetes, the proper management of blood glucose levels is essential. Previously, ultrasonic transdermal methods using a light-weight cymbal transducer array has been studied for noninvasive methods of insulin delivery for Type-1 diabetes and glucose level monitoring. In this study, the ultrasound systems of insulin delivery and glucose sensing have been combined by a feedback controller. This study was designed to show the feasibility of the feedback controlled ultrasound system for the noninvasive glucose control. For perspective human application, in vivo experiments were performed on large animals that have a similar size to humans. Four in vivo experiments were performed using about 200 lbs pigs. The cymbal array of 3×3 pattern has been used for insulin delivery at 30 kHz with the spatial-peak temporal-peak intensity (Isptp) of 100 mW/cm2. For glucose sensing, a 2×2 array was operated at 20 kHz with Isptp = 100 mW/cm2. Based on the glucose level determined by biosensors after the ultrasound exposure, the ultrasound system for the insulin delivery was automatically operated. The glucose level of 115 mg/dl was set as a reference value for operating the insulin delivery system. For comparison, the glucose levels of blood samples collected from the ear vein were measured by a commercial glucose meter. Using the ultrasound system operated by the close-loop, feed-back controller, the glucose levels of four pigs were determined every 20 minutes and continuously controlled for 120 minutes. In comparison to the commercial glucose meter, the glucose levels determined by the biosensor were slightly higher. The results of in vivo experiments indicate the feasibility of the feedback controlled ultrasound system using the cymbal array for noninvasive glucose sensing and insulin delivery. Further studies on the extension of the glucose control will be continued for the effective method of glucose control.

  19. Osmotically driven drug delivery through remote-controlled magnetic nanocomposite membranes

    KAUST Repository

    Zaher, A.

    2015-09-29

    Implantable drug delivery systems can provide long-term reliability, controllability, and biocompatibility, and have been used in many applications, including cancer pain and non-malignant pain treatment. However, many of the available systems are limited to zero-order, inconsistent, or single burst event drug release. To address these limitations, we demonstrate prototypes of a remotely operated drug delivery device that offers controllability of drug release profiles, using osmotic pumping as a pressure source and magnetically triggered membranes as switchable on-demand valves. The membranes are made of either ethyl cellulose, or the proposed stronger cellulose acetate polymer, mixed with thermosensitive poly(N-isopropylacrylamide) hydrogel and superparamagnetic iron oxide particles. The prototype devices\\' drug diffusion rates are on the order of 0.5–2 μg/h for higher release rate designs, and 12–40 ng/h for lower release rates, with maximum release ratios of 4.2 and 3.2, respectively. The devices exhibit increased drug delivery rates with higher osmotic pumping rates or with magnetically increased membrane porosity. Furthermore, by vapor deposition of a cyanoacrylate layer, a drastic reduction of the drug delivery rate from micrograms down to tens of nanograms per hour is achieved. By utilizing magnetic membranes as the valve-control mechanism, triggered remotely by means of induction heating, the demonstrated drug delivery devices benefit from having the power source external to the system, eliminating the need for a battery. These designs multiply the potential approaches towards increasing the on-demand controllability and customizability of drug delivery profiles in the expanding field of implantable drug delivery systems, with the future possibility of remotely controlling the pressure source.

  20. Infection control in delivery care units, Gujarat state, India: A needs assessment

    Directory of Open Access Journals (Sweden)

    Ramani KV

    2011-05-01

    Full Text Available Abstract Background Increasingly, women in India attend health facilities for childbirth, partly due to incentives paid under government programs. Increased use of health facilities can alleviate the risks of infections contracted in unhygienic home deliveries, but poor infection control practices in labour and delivery units also cause puerperal sepsis and other infections of childbirth. A needs assessment was conducted to provide information on procedures and practices related to infection control in labour and delivery units in Gujarat state, India. Methods Twenty health care facilities, including private and public primary health centres and referral hospitals, were sampled from two districts in Gujarat state, India. Three pre-tested tools for interviewing and for observation were used. Data collection was based on existing infection control guidelines for clean practices, clean equipment, clean environment and availability of diagnostics and treatment. The study was carried out from April to May 2009. Results Seventy percent of respondents said that standard infection control procedures were followed, but a written procedure was only available in 5% of facilities. Alcohol rubs were not used for hand cleaning and surgical gloves were reused in over 70% of facilities, especially for vaginal examinations in the labour room. Most types of equipment and supplies were available but a third of facilities did not have wash basins with "hands-free" taps. Only 15% of facilities reported that wiping of surfaces was done immediately after each delivery in labour rooms. Blood culture services were available in 25% of facilities and antibiotics are widely given to women after normal delivery. A few facilities had data on infections and reported rates of 3% to 5%. Conclusions This study of current infection control procedures and practices during labour and delivery in health facilities in Gujarat revealed a need for improved information systems

  1. Controlled delivery of SDF-1α and IGF-1: CXCR4+ cell recruitment and functional skeletal muscle recovery

    Science.gov (United States)

    Rybalko, Viktoriya Y.; Pham, Chantal B.; Hsieh, Pei-Ling; Hammers, David W.; Merscham-Banda, Melissa; Suggs, Laura J.; Farrar, Roger P.

    2017-01-01

    Therapeutic delivery of regeneration-promoting biological factors directly to the site of injury has demonstrated its efficacy in various injury models. Several reports describe improved tissue regeneration following local injection of tissue specific growth factors, cytokines and chemokines. Evidence exists that combined cytokine/growth factor treatment is superior for optimizing tissue repair by targeting different aspects of the regeneration response. The purpose of this study was to evaluate the therapeutic potential of the controlled delivery of stromal cell-derived factor-1alpha (SDF-1α) alone or in combination with insulin-like growth factor-I (SDF-1α/IGF-I) for the treatment of tourniquet-induced ischemia/reperfusion injury (TK-I/R) of skeletal muscle. We hypothesized that SDF-1α will promote sustained stem cell recruitment to the site of muscle injury, while IGF-I will induce progenitor cell differentiation to effectively restore muscle contractile function after TK-I/R injury while concurrently reducing apoptosis. Utilizing a novel poly-ethylene glycol PEGylated fibrin gel matrix (PEG-Fib), we incorporated SDF-1α alone (PEG-Fib/SDF-1α) or in combination with IGF-I (PEG-Fib/SDF-1α/IGF-I) for controlled release at the site of acute muscle injury. Despite enhanced cell recruitment and revascularization of the regenerating muscle after SDF-1α treatment, functional analysis showed no benefit from PEG-Fib/SDF-1α therapy, while dual delivery of PEG-Fib/SDF-1α/IGF-I resulted in IGF-I-mediated improvement of maximal force recovery and SDF-1α-driven in vivo neovasculogenesis. Histological data supported functional data, as well as highlighted the important differences in the regeneration process among treatment groups. This study provides evidence that while revascularization may be necessary for maximizing muscle force recovery, without modulation of other effects of inflammation it is insufficient. PMID:26247892

  2. Controlled delivery of SDF-1α and IGF-1: CXCR4(+) cell recruitment and functional skeletal muscle recovery.

    Science.gov (United States)

    Rybalko, Viktoriya Y; Pham, Chantal B; Hsieh, Pei-Ling; Hammers, David W; Merscham-Banda, Melissa; Suggs, Laura J; Farrar, Roger P

    2015-11-01

    Therapeutic delivery of regeneration-promoting biological factors directly to the site of injury has demonstrated its efficacy in various injury models. Several reports describe improved tissue regeneration following local injection of tissue specific growth factors, cytokines and chemokines. Evidence exists that combined cytokine/growth factor treatment is superior for optimizing tissue repair by targeting different aspects of the regeneration response. The purpose of this study was to evaluate the therapeutic potential of the controlled delivery of stromal cell-derived factor-1alpha (SDF-1α) alone or in combination with insulin-like growth factor-I (SDF-1α/IGF-I) for the treatment of tourniquet-induced ischemia/reperfusion injury (TK-I/R) of skeletal muscle. We hypothesized that SDF-1α will promote sustained stem cell recruitment to the site of muscle injury, while IGF-I will induce progenitor cell differentiation to effectively restore muscle contractile function after TK-I/R injury while concurrently reducing apoptosis. Utilizing a novel poly-ethylene glycol PEGylated fibrin gel matrix (PEG-Fib), we incorporated SDF-1α alone (PEG-Fib/SDF-1α) or in combination with IGF-I (PEG-Fib/SDF-1α/IGF-I) for controlled release at the site of acute muscle injury. Despite enhanced cell recruitment and revascularization of the regenerating muscle after SDF-1α treatment, functional analysis showed no benefit from PEG-Fib/SDF-1α therapy, while dual delivery of PEG-Fib/SDF-1α/IGF-I resulted in IGF-I-mediated improvement of maximal force recovery and SDF-1α-driven in vivo neovasculogenesis. Histological data supported functional data, as well as highlighted the important differences in the regeneration process among treatment groups. This study provides evidence that while revascularization may be necessary for maximizing muscle force recovery, without modulation of other effects of inflammation it is insufficient.

  3. Development of novel encapsulated formulations using albumin-chitosan as a polymer matrix for ocular drug delivery

    Science.gov (United States)

    Addo, Richard Tettey

    Designing formulations for ophthalmic drug delivery is one of the most challenging endeavors facing the pharmaceutical scientist due to the unique anatomy, physiology, and biochemistry of the eye. Current treatment protocols for administration of drugs in eye diseases are primarily solution formulations, gels or ointments. However, these modes of delivery have several drawbacks such as short duration of exposure, need for repeated administrations and non-specific toxicity. We hypothesize that development of ocular drugs in microparticles will overcome the deficiencies of the current modalities of treatment. We based the hypothesis on the preliminary studies conducted with encapsulated tetracaine, an anesthetic used for surgical purposes and atropine, a medication used for several ophthalmic indications including mydriatic and cycloplegic effects. However, atropine is well absorbed into the systemic circulation and has been reported to exert severe systemic side effects after ocular administration (Hoefnagel D. 1961, Morton H. G. 1939 and Lang J. C. 1995) and may lead to serious side effects including death in extreme cases with pediatric use. Based on these observations, the focus of this dissertation is to formulate microparticulate drug carrier for treatment of various conditions of the eye. Purpose: To prepare, characterize, study the in vitro and in vivo interaction of albumin-chitosan microparticles (BSA-CSN MS), a novel particulate drug carrier for ocular drug delivery. Method: Microparticle formulations were prepared by method of spray drying. The percentage drug loading and efficiency were assessed using USP (I) dissolution apparatus. Using Malvern Zeta-Sizer, we determined size and surface charge of the fabrication. Surface morphology of the microparticles was examined using Scanning Electron Microscopy. Microparticles were characterized in terms of thermal properties using Differential Scanning Calorimetry. Human corneal epithelial cells (HCET-1) were

  4. Facility Delivery, Postnatal Care and Neonatal Deaths in India: Nationally-Representative Case-Control Studies.

    Directory of Open Access Journals (Sweden)

    Shaza A Fadel

    Full Text Available Clinical studies demonstrate the efficacy of interventions to reduce neonatal deaths, but there are fewer studies of their real-life effectiveness. In India, women often seek facility delivery after complications arise, rather than to avoid complications. Our objective was to quantify the association of facility delivery and postnatal checkups with neonatal mortality while examining the "reverse causality" in which the mothers deliver at a health facility due to adverse perinatal events.We conducted nationally representative case-control studies of about 300,000 live births and 4,000 neonatal deaths to examine the effect of, place of delivery and postnatal checkup on neonatal mortality. We compared neonatal deaths to all live births and to a subset of live births reporting excessive bleeding or obstructed labour that were more comparable to cases in seeking care.In the larger study of 2004-8 births, facility delivery without postnatal checkup was associated with an increased odds of neonatal death (Odds ratio = 2.5; 99% CI 2.2-2.9, especially for early versus late neonatal deaths. However, use of more comparable controls showed marked attenuation (Odds ratio = 0.5; 0.4-0.5. Facility delivery with postnatal checkup was associated with reduced odds of neonatal death. Excess risks were attenuated in the earlier study of 2001-4 births.The combined effect of facility deliveries with postnatal checks ups is substantially higher than just facility delivery alone. Evaluation of the real-life effectiveness of interventions to reduce child and maternal deaths need to consider reverse causality. If these associations are causal, facility delivery with postnatal check up could avoid about 1/3 of all neonatal deaths in India (~100,000/year.

  5. Monolithic Controlled Delivery Systems: Part II. Basic Mathematical Models

    Directory of Open Access Journals (Sweden)

    Rumiana Blagoeva

    2006-12-01

    Full Text Available The article presents a brief but comprehensive review of the large variety of mathematical models of drug controlled release from polymeric monoliths in the last 25 years. The models are considered systematically, from the first simple empirical models up to the most comprehensive theoretical ones taking into account the main release mechanisms (diffusion, swelling, dissolution or erosion simultaneously. Their advantages and limitations are briefly discussed and some applications are outlined. The present review shows the choice of appropriate mathematical model for a particular controlled system design mainly depends on the desired predictive ability and accuracy of the model. This aspect is connected with the necessity the main factors influencing the concrete release kinetics, especially the basic controlling mechanisms, to be identified in advance.

  6. Application of Transfer Matrix Approach to Modeling and Decentralized Control of Lattice-Based Structures

    Science.gov (United States)

    Cramer, Nick; Swei, Sean Shan-Min; Cheung, Kenny; Teodorescu, Mircea

    2015-01-01

    This paper presents a modeling and control of aerostructure developed by lattice-based cellular materials/components. The proposed aerostructure concept leverages a building block strategy for lattice-based components which provide great adaptability to varying ight scenarios, the needs of which are essential for in- ight wing shaping control. A decentralized structural control design is proposed that utilizes discrete-time lumped mass transfer matrix method (DT-LM-TMM). The objective is to develop an e ective reduced order model through DT-LM-TMM that can be used to design a decentralized controller for the structural control of a wing. The proposed approach developed in this paper shows that, as far as the performance of overall structural system is concerned, the reduced order model can be as e ective as the full order model in designing an optimal stabilizing controller.

  7. Advances in research of targeting delivery and controlled release of drug-loaded nanoparticles

    International Nuclear Information System (INIS)

    Tan Zhonghua

    2003-01-01

    Biochemistry drug, at present, is still the main tool that human struggle to defeat the diseases. So, developing safe and efficacious technique of drug targeting delivery and controlled release is key to enhance curative effect, decrease drug dosage, and lessen its side effect. Drug-loaded nanoparticles, which is formed by conjugate between nanotechnology and modern pharmaceutics, is a new fashioned pharmic delivery carrier. Because of advantages in pharmic targeting transport and controlled or slow release and improving bioavailability, it has been one of developing trend of modern pharmaceutical dosage forms

  8. Development of a Controlled Release of Salicylic Acid Loaded Stearic Acid-Oleic Acid Nanoparticles in Cream for Topical Delivery

    Directory of Open Access Journals (Sweden)

    J. O. Woo

    2014-01-01

    Full Text Available Lipid nanoparticles are colloidal carrier systems that have extensively been investigated for controlled drug delivery, cosmetic and pharmaceutical applications. In this work, a cost effective stearic acid-oleic acid nanoparticles (SONs with high loading of salicylic acid, was prepared by melt emulsification method combined with ultrasonication technique. The physicochemical properties, thermal analysis and encapsulation efficiency of SONs were studied. TEM micrographs revealed that incorporation of oleic acid induces the formation of elongated spherical particles. This observation is in agreement with particle size analysis which also showed that the mean particle size of SONs varied with the amount of OA in the mixture but with no effect on their zeta potential values. Differential scanning calorimetry analysis showed that the SONs prepared in this method have lower crystallinity as compared to pure stearic acid. Different amount of oleic acid incorporated gave different degree of perturbation to the crystalline matrix of SONs and hence resulted in lower degrees of crystallinity, thereby improving their encapsulation efficiencies. The optimized SON was further incorporated in cream and its in vitro release study showed a gradual release for 24 hours, denoting the incorporation of salicylic acid in solid matrix of SON and prolonging the in vitro release.

  9. Controlling Fungal Biofilms with Functional Drug Delivery Denture Biomaterials

    OpenAIRE

    Wen, Jianchuan; Jiang, Fuguang; Yeh, Chih-Ko; Sun, Yuyu

    2015-01-01

    Candida -associated denture stomatitis (CADS), caused by colonization and biofilm-formation of Candida species on denture surfaces, is a significant clinical concern. We show here that modification of conventional denture materials with functional groups can significantly increase drug binding capacity and control drug release rate of the resulting denture materials for potentially managing CADS. In our approach, poly(methyl methacrylate) (PMMA)-based denture resins were surface grafted with ...

  10. Solar-powered oxygen delivery: study protocol for a randomized controlled trial.

    Science.gov (United States)

    Nyende, Saleh; Conroy, Andrea; Opoka, Robert Opika; Namasopo, Sophie; Kain, Kevin C; Mpimbaza, Arthur; Bhargava, Ravi; Hawkes, Michael

    2015-07-09

    Pneumonia is a leading cause of childhood mortality globally. Oxygen therapy improves survival in children with pneumonia, yet its availability remains limited in many resource-constrained settings where most deaths occur. Solar-powered oxygen delivery could be a sustainable method to improve oxygen delivery in remote areas with restricted access to a supply chain of compressed oxygen cylinders and reliable electrical power. This study is a randomized controlled trial (RCT). Solar-powered oxygen delivery systems will be compared to a conventional method (oxygen from cylinders) in patients with hypoxemic respiratory illness. Enrollment will occur at two sites in Uganda: Jinja Regional Referral Hospital and Kambuga District Hospital. The primary outcome will be the length of hospital stay. Secondary study endpoints will be mortality, duration of supplemental oxygen therapy (time to wean oxygen), proportion of patients successfully oxygenated, delivery system failure, cost, system maintenance and convenience. The RCT will provide useful data on the feasibility and noninferiority of solar-powered oxygen delivery. This technological innovation uses freely available inputs, the sun and the air, to oxygenate children with pneumonia, and can be applied "off the grid" in remote and/or resource-constrained settings where most pneumonia deaths occur. If proven successful, solar-powered oxygen delivery systems could be scaled up and widely implemented for impact on global child mortality. Clinicaltrials.gov registration number NCT0210086 (date of registration: 27 March, 2014).

  11. After Delivery

    Science.gov (United States)

    ... Size: A A A Listen En Español After Delivery After your baby arrives, your body begins to recover from the hard work of pregnancy and delivery. Some new mothers have better blood glucose control ...

  12. Controlled release of simvastatin from biomimetic β-TCP drug delivery system.

    Directory of Open Access Journals (Sweden)

    Joshua Chou

    Full Text Available Simvastatin have been shown to induce bone formation and there is currently a urgent need to develop an appropriate delivery system to sustain the release of the drug to increase therapeutic efficacy whilst reducing side effects. In this study, a novel drug delivery system for simvastatin by means of hydrothermally converting marine exoskeletons to biocompatible beta-tricalcium phosphate was investigated. Furthermore, the release of simvastatin was controlled by the addition of an outer apatite coating layer. The samples were characterized by x-ray diffraction analysis, fourier transform infrared spectroscopy, scanning electron microscopy and mass spectroscopy confirming the conversion process. The in-vitro dissolution of key chemical compositional elements and the release of simvastatin were measured in simulated body fluid solution showing controlled release with reduction of approximately 25% compared with un-coated samples. This study shows the potential applications of marine structures as a drug delivery system for simvastatin.

  13. Conductive polymer nanotube patch for fast and controlled in vivo transdermal drug delivery

    Science.gov (United States)

    Nguyen, Thao M.

    Transdermal drug delivery has created new applications for existing therapies and offered an alternative to the traditional oral route where drugs can prematurely metabolize in the liver causing adverse side effects. Opening the transdermal delivery route to large hydrophilic drugs is one of the greatest challenges due to the hydrophobicity of the skin. However, the ability to deliver hydrophilic drugs using a transdermal patch would provide a solution to problems of other delivery methods for hydrophilic drugs. The switching of conductive polymers (CP) between redox states cause simultaneous changes in the polymer charge, conductivity, and volume—properties that can all be exploited in the biomedical field of controlled drug delivery. Using the template synthesis method, poly(3,4-ethylenedioxythiophene (PEDOT) nanotubes were synthesized electrochemically and a transdermal drug delivery patch was successfully designed and developed. In vitro and in vivo uptake and release of hydrophilic drugs were investigated. The relationship between the strength of the applied potential and rate of drug release were also investigated. Results revealed that the strength of the applied potential is proportional to the rate of drug release; therefore one can control the rate of drug release by controlling the applied potential. The in vitro studies focused on the kinetics of the drug delivery system. It was determined that the drug released mainly followed zero-order kinetics. In addition, it was determined that applying a releasing potential to the transdermal drug delivery system lead to a higher release rate constant (up to 7 times greater) over an extended period of time (˜24h). In addition, over 24 hours, an average of 80% more model drug molecules were released with an applied potential than without. The in vivo study showed that the drug delivery system was capable of delivering model hydrophilic drugs molecules through the dermis layer of the skin within 30 minutes

  14. Living in the matrix: assembly and control of Vibrio cholerae biofilms

    Science.gov (United States)

    Teschler, Jennifer K.; Zamorano-Sánchez, David; Utada, Andrew S.; Warner, Christopher J. A.; Wong, Gerard C. L.; Linington, Roger G.; Yildiz, Fitnat H.

    2015-01-01

    Preface Nearly all bacteria form biofilms as a strategy for survival and persistence. Biofilms are associated with biotic and abiotic surfaces and are composed of aggregates of cells that are encased by a self-produced or acquired extracellular matrix. Vibrio cholerae has been studied as a model organism for understanding biofilm formation in environmental pathogens, as it spends much of its life cycle outside of the human host in the aquatic environment. Given the important role of biofilm formation in the V. cholerae life cycle, the molecular mechanisms underlying this process and the signals that trigger biofilm assembly or dispersal have been areas of intense investigation over the past 20 years. In this Review, we discuss V. cholerae surface attachment, various matrix components and the regulatory networks controlling biofilm formation. PMID:25895940

  15. Photodegradation as a mechanism for controlled drug delivery.

    Science.gov (United States)

    Griffin, Donald R; Patterson, Joseph T; Kasko, Andrea M

    2010-12-15

    A drug-releasing model compound based on photosensitive acrylated ortho-nitrobenzylether (o-NBE) moiety and fluorescein was synthesized to demonstrate photolysis as a mechanism for drug release. Release of this model compound from a hydrogel network can be controlled with light intensity (5-20 mW/cm(2)), exposure duration (0-20 min) and wavelength (365, 405, 436 nm). Due to the high molar absorptivity of the compound (5,984 M(-1) cm(-1)), light attenuation is significant in this system. Light attenuation can be used to self-limit the dosing from a hydrogel, and allow subsequent release from the drug reservoir after equilibration, or attenuation can be utilized to create a chemical gradient within the hydrogel. A model of photodegradation that uses an integrated form of Beer-Lambert's law quantitatively predicts release from hydrophilic hydrogels with low crosslink density, but fails to quantitatively predict release from more hydrophobic systems, presumably due to partitioning of the hydrophobic model compound in the hydrogel. In contrast to other mechanisms of release (enzymolysis, hydrolysis), photolysis provides real-time on demand control over drug release along with the unique ability to create chemical gradients within the hydrogel. © 2010 Wiley Periodicals, Inc.

  16. Study of high-pressure cryogenic pumps with different methods of delivery control

    International Nuclear Information System (INIS)

    Braun, V.M.; Brailovskii, Y.L.; Pavlenko, Y.A.; Tsokalo, I.V.

    1986-01-01

    This paper describes new reciprocating pumps with smooth control of delivery in a running pump. Control is effected either by changing the length of the piston stroke or by changing the speed of the driving motor. The individual features of the two methods are described. In the first method (mechanical), delivery is controlled in the range 50 to 100%. A separate actuating mechanism is needed to connect the pump to an automatic control system. This method complicates the driving mechanism and increases the bulk and cost of production. In the second method of controlling the speed of the electric motor, an electric drive fitted with a frequency thyristor is used. AC induction motors series 4A working at current frequencies of 60 HZ are used. By this method, delivery control could be enhanced by 1.3 times. Comparative tests were made on pumps using the above methods of control. The tests demonstrated the possibilities of using the frequency thyristor converters. The complexity and high cost of EKT type drives is largely compensated by the convenience and simplicity of control in a wide range. The mechanical control is advantageous only in low-output units

  17. Determinants of institutional delivery among childbearing age women in Western Ethiopia, 2013: unmatched case control study.

    Science.gov (United States)

    Feyissa, Tesfaye Regassa; Genemo, Gebi Agero

    2014-01-01

    Place of delivery is a crucial factor which affects the health and wellbeing of the mother and newborn. Institutional delivery helps the women to access skilled assistance, drugs, equipment, and referral transport. Even though 34% of pregnant women received at least one antenatal care from a skilled provider in Ethiopia by 2013, institutional delivery was 10%. The main objective of the study was to assess determinants of institutional delivery in Western Ethiopia. Retrospective unmatched case control study design was used to assess determinants of institutional delivery in Western Ethiopia from September to October 2013. A total of 320 respondents from six districts of East Wollega zone, West Ethiopia were included. Data were collected using pretested and structured questionnaires. Data were entered and cleaned by Epi-info then exported and analyzed using SPSS software. Statistical significance was determined through a 95% confidence level. Education [Adjusted Odds Ratio (AOR) (95% Confidence Interval (CI)) = 2.754(1.510-8.911)], family size [AOR (95% CI) = .454(.209-.984)], residence [AOR (95% CI) = 3.822 (1.766-8.272)] were important predictors of place of delivery. Four or more antenatal care [(ANC) (AOR (95% CI) = 2.914(1.105-7.682)], birth order [(AOR (95% CI) = .136(.054-.344), age at last delivery [(AOR (95% CI) = 9.995(2.101-47.556)], birth preparedness [AOR (95% CI) = 6.957(2.422-19.987)], duration of labour [AOR (95% CI) = 3.541(1.732-7.239)] were significantly associated with institutional delivery. Moreover service related factors such as distance from health institutions [AOR (95% CI) = .665(.173-.954)], respondents' awareness of skill of health care professionals [AOR (95% CI) = 2.454 (1.663-6.255)], mode of transportations [AOR (95% CI) = .258(.122-.549)] were significantly associated with institutional delivery. Policy makers, health service organizations, community leaders and other concerned bodies have

  18. Determinants of institutional delivery among childbearing age women in Western Ethiopia, 2013: unmatched case control study.

    Directory of Open Access Journals (Sweden)

    Tesfaye Regassa Feyissa

    Full Text Available BACKGROUND: Place of delivery is a crucial factor which affects the health and wellbeing of the mother and newborn. Institutional delivery helps the women to access skilled assistance, drugs, equipment, and referral transport. Even though 34% of pregnant women received at least one antenatal care from a skilled provider in Ethiopia by 2013, institutional delivery was 10%. The main objective of the study was to assess determinants of institutional delivery in Western Ethiopia. METHODS: Retrospective unmatched case control study design was used to assess determinants of institutional delivery in Western Ethiopia from September to October 2013. A total of 320 respondents from six districts of East Wollega zone, West Ethiopia were included. Data were collected using pretested and structured questionnaires. Data were entered and cleaned by Epi-info then exported and analyzed using SPSS software. Statistical significance was determined through a 95% confidence level. RESULTS: Education [Adjusted Odds Ratio (AOR (95% Confidence Interval (CI = 2.754(1.510-8.911], family size [AOR (95% CI = .454(.209-.984], residence [AOR (95% CI = 3.822 (1.766-8.272] were important predictors of place of delivery. Four or more antenatal care [(ANC (AOR (95% CI = 2.914(1.105-7.682], birth order [(AOR (95% CI = .136(.054-.344, age at last delivery [(AOR (95% CI = 9.995(2.101-47.556], birth preparedness [AOR (95% CI = 6.957(2.422-19.987], duration of labour [AOR (95% CI = 3.541(1.732-7.239] were significantly associated with institutional delivery. Moreover service related factors such as distance from health institutions [AOR (95% CI = .665(.173-.954], respondents' awareness of skill of health care professionals [AOR (95% CI = 2.454 (1.663-6.255], mode of transportations [AOR (95% CI = .258(.122-.549] were significantly associated with institutional delivery. CONCLUSIONS AND RECOMMENDATIONS: Policy makers, health service

  19. Smart polymers for controlled delivery of proteins and peptides: a review of patents.

    Science.gov (United States)

    Fogueri, Laxmi R; Singh, Somnath

    2009-01-01

    Protein and peptide-based therapeutic agents have unique physiochemical properties such as high molecular weight, short half life, requirement of a sustained plasma level for the desired therapeutic effect, liable to physical and chemical instability by gastric enzymes and harsh acidic environment as well as first pass metabolism, which makes their delivery a challenge. The delivery of proteins and peptides using various routes of administration like oral, nasal, rectal, pulmonary, buccal, vaginal and transdermal route is found to exhibit limitations, poor permeability and degradation being major limitations. Use of parenteral route is found to overcome these problems but patient compliance is poor due to the need for frequent administration. Use of control delivery for these drugs using smart polymers seems promising as they overcome the limitations posed by other routes of delivery. Smart polymers increase patient compliance, maintain stability of the drug, and maintain drug level in therapeutic window and are easy to manufacture. Different types of smart polymer-based delivery systems, such as sensitive to temperature, phase, pH, electric charge, light, and biochemicals, and their application in controlling the release of the incorporated drug to obtain a sustained plasma level has been discussed. Smart polymers, however, face challenges with regard to high burst release, unpredictable behavior in later part of biphasic release profile, overall drug release kinetics, conformational stability during processing, and preserving biological activity after getting released. Several patents overcoming these inherent problems associated with smart polymers have been reviewed. At the end, the future direction and potential of smart polymer-based delivery system for drug delivery has been presented in brief.

  20. Modeling, Simulation and Control of Matrix Convert for Variable Speed Wind Turbine System

    Directory of Open Access Journals (Sweden)

    M. Alizadeh Moghadam

    2015-09-01

    Full Text Available This paper presents modeling, simulation and control of matrix converter (MC for variable speed wind turbine (VSWT system including permanent magnet synchronous generator (PMSG. At a given wind velocity, the power available from a wind turbine is a function of its shaft speed. In order to track maximum power, the MC adjusts the PMSG shaft speed.The proposed control system allowing independent control maximum power point tracking (MPPT of generator side and regulate reactive power of grid side for the operation of the VSWT system. The MPPT is implemented by a new control system. This control system is based on control of zero d-axis current (ZDC. The ZDC control can be realized by transfer the three-phase stator current in the stationary reference frame into d-and q-axis components in the synchronous reference frame. Also this paper is presented, a novel control strategy to regulate the reactive power supplied by a variable speed wind energy conversion system. This control strategy is based on voltage oriented control (VOC. The simulation results based on Simulink/Matlab software show that the controllers can extract maximum power and regulate reactive power under varying wind velocities.

  1. Stability Analysis of Wireless Measurement and Control System Based on Dynamic Matrix

    Directory of Open Access Journals (Sweden)

    Yongxian SONG

    2014-01-01

    Full Text Available Focus on data packet loss and time delay problems in wireless greenhouse measurement and control system, and temperature and humidity were taken as the research objects, the model of temperature and humidity information transmission was set up by decoupling technology according to the characteristics of wireless greenhouse measurement and control system. According to related theory of exponential stability in network control system, the stability conditions judgment of temperature and humidity control model was established, the linear matrix inequality that time delay and packet loss should satisfy was obtained when wireless measurement and control system was stable operation. The feasibility analysis of linear matrix inequality (LMI was implemented Using LMI toolbox in MATLAB, and the critical values of time delay and packet loss rate were obtained when the system was stable operation. The wireless sensor network control system simulation model with time delay and packet loss was set up using TrueTime toolbox. The simulation results have shown that the system was in a stable state when time delay and packet loss rate obtained were less than the critical values in wireless greenhouse sensor network measurement and control system; With the increase of time delay and packet loss rate, and stable performance drops; When time delay and packet loss rate obtained were more than the critical values, the measurement and control system would be in a state of flux, and when it was serious, even can lead to collapse of the whole system. As a result, the critical values determination of time delay and packet loss rate provided a theoretical basis for establishing stable greenhouse wireless sensor network (WSN measurement and control system in practical application.

  2. The analgesic efficacy of transversus abdominis plane block after cesarean delivery: a randomized controlled trial.

    LENUS (Irish Health Repository)

    McDonnell, John G

    2008-01-01

    The transversus abdominis plane (TAP) block is an effective method of providing postoperative analgesia in patients undergoing midline abdominal wall incisions. We evaluated its analgesic efficacy over the first 48 postoperative hours after cesarean delivery performed through a Pfannensteil incision, in a randomized controlled, double-blind, clinical trial.

  3. Delivery Pain Anxiety/Fear Control between Midwives among Women in Cross River State, Nigeria

    Science.gov (United States)

    Oyira, Emilia James; Mgbekem, Mary; Osuchukwu, Easther Chukwudi; Affiong, Ekpenyong Onoyom; Lukpata, Felicia E.; Ojong-Alasia, Mary Manyo

    2016-01-01

    Objective: To examine background of midwives the effectiveness in delivery pain and anxiety/fear control of expectant mothers in Nigeria. Methods: Two null hypotheses were formulated. The survey design with sample of 360 post-natal women was selected from a population of 78,814 through the polio immunization registers of selected health center in…

  4. A modified Finite Element-Transfer Matrix for control design of space structures

    Science.gov (United States)

    Tan, T.-M.; Yousuff, A.; Bahar, L. Y.; Konstandinidis, M.

    1990-01-01

    The Finite Element-Transfer Matrix (FETM) method was developed for reducing the computational efforts involved in structural analysis. While being widely used by structural analysts, this method does, however, have certain limitations, particularly when used for the control design of large flexible structures. In this paper, a new formulation based on the FETM method is presented. The new method effectively overcomes the limitations in the original FETM method, and also allows an easy construction of reduced models that are tailored for the control design. Other advantages of this new method include the ability to extract open loop frequencies and mode shapes with less computation, and simplification of the design procedures for output feedback, constrained compensation, and decentralized control. The development of this new method and the procedures for generating reduced models using this method are described in detail and the role of the reduced models in control design is discussed through an illustrative example.

  5. Porous nano-HA/collagen/PLLA scaffold containing chitosan microspheres for controlled delivery of synthetic peptide derived from BMP-2.

    Science.gov (United States)

    Niu, Xufeng; Feng, Qingling; Wang, Mingbo; Guo, Xiaodong; Zheng, Qixin

    2009-03-04

    It is advantageous to incorporate controlled growth factor delivery into tissue engineering strategies. The purpose of the present study was to develop a novel tissue engineering scaffold with the capability of controlled releasing BMP-2-derived synthetic peptide. Porous nano-hydroxyapatite/collagen/poly(L-lactic acid)/chitosan microspheres (nHAC/PLLA/CMs) composite scaffolds containing different quantities of chitosan microspheres (CMs) were prepared by a thermally induced phase separation method. Dioxane was used as the solvent for PLLA. Introduction of less than 30% of CMs (on PLLA weight basis) did not remarkably affect the morphology and porosity of the nHAC/PLLA/CMs scaffolds. However, as the microspheres contents increased to 50%, the porosity of the composite decreased rapidly. The compressive modulus of the composite scaffolds increased from 15.4 to 25.5 MPa, while the compressive strength increased from 1.42 to 1.63 MPa as the microspheres contents increased from 0% to 50%. The hydrolytic degradation and synthetic peptide release kinetics in vitro were investigated by incubation in phosphate buffered saline solution (pH 7.4). The results indicated that the degradation rate of the scaffolds was increased with the enhancement of CMs dosage. The synthetic peptide was released in a temporally controlled manner, depending on the degradation of both incorporated chitosan microspheres and PLLA matrix. In vitro bioactivity assay revealed that the encapsulated synthetic peptide was biologically active as evidenced by stimulation of rabbit marrow mesenchymal stem cells (MSCs) alkaline phosphatase (ALP) activity. The successful microspheres-scaffold system offers a new delivery method of growth factors and a novel scaffold design for bone regeneration.

  6. QA Issues for Computer-Controlled Treatment Delivery: This Is Not Your Old R/V System Any More!

    International Nuclear Information System (INIS)

    Fraass, Benedick A.

    2008-01-01

    State-of-the-art radiotherapy treatment delivery has changed dramatically during the past decade, moving from manual individual field setup and treatment to automated computer-controlled delivery of complex treatments, including intensity-modulated radiotherapy and other similarly complex delivery strategies. However, the quality assurance methods typically used to ensure treatment is performed precisely and correctly have not evolved in a similarly dramatic way. This paper reviews the old manual treatment process and use of record-and-verify systems, and describes differences with modern computer-controlled treatment delivery. The process and technology used for computer-controlled treatment delivery are analyzed in terms of potential (and actual) problems, as well as relevant published guidance on quality assurance. The potential for improved quality assurance for computer-controlled delivery is discussed

  7. Designing dapsone polymer conjugates for controlled drug delivery.

    Science.gov (United States)

    Rojo, Luis; Fernandez-Gutierrez, Mar; Deb, Sanjukta; Stevens, Molly M; San Roman, Julio

    2015-11-01

    Polymer-drug conjugates have significantly influenced polymer therapeutics over the last decade via controlled pharmacokinetics. Dapsone (4,4'-diamino diphenylsulphone) is not only widely used in the treatment of leprosy but forms an essential component in the treatment of autoimmune inflammatory diseases and malaria. However, its low bioavailability and non-specific distribution in the body leads to absorption throughout organs including skin, liver, and kidneys that can cause serious side effects. Thus, in this study we report the synthesis of polymer-drug conjugates of dapsone covalently bonded to macromolecular chains towards the development of new bioactive polymeric formulations with anti-inflammatory properties. Dapsone was functionalised with an acrylic moiety in which the acrylamide residue was directly bonded to one of the aromatic rings of dapsone. This functionalisation yielded an unsymmetrical dapsone methacrylamide (DapMA) structure, which on free radical polymerisation and co-polymerisation with HEMA yielded polymers of hydrocarbon macromolecules with pendant dapsone units. Thermal and size-exclusion chromatographic analysis revealed an increase in thermal stabilisation of the homopolymer (p(DapMA)) in comparison to the copolymer (p(Dap-co-HEMA)) with relatively high average molecular weight. The polymer conjugates exhibited high stability with low dapsone release from the polymeric backbone due to hydrolysis. However, a significant anti-inflammatory activity in a nitric oxide inhibition assay confirmed that this property was the consequence of only the macromolecular composition and not related to the release of low molecular weight compounds. Thus, the conjugation of dapsone to macromolecular systems provides a synthetic route to incorporate this drug into polymeric systems, facilitating their development into new anti-inflammatory therapies. The dapsone-conjugated methacrylic monomer and polymer derivatives with anti-inflammatory properties

  8. Spatiotemporal Control of Doxorubicin Delivery from “Stealth-Like” Prodrug Micelles

    Science.gov (United States)

    Kong, Li; Schneider, Gregory F.; Campbell, Frederick

    2017-01-01

    In the treatment of cancer, targeting of anticancer drugs to the tumor microenvironment is highly desirable. Not only does this imply accurate tumor targeting but also minimal drug release en route to the tumor and maximal drug release once there. Here we describe high-loading, “stealth-like” doxorubicin micelles as a pro-drug delivery system, which upon light activation, leads to burst-like doxorbicin release. Through this approach, we show precise spatiotemporal control of doxorubicin delivery to cells in vitro. PMID:28937592

  9. Dithiocarbamate chitosan as a potential polymeric matrix for controlled drug release.

    Science.gov (United States)

    Kim, Youn Taeg; Yum, Soohwan; Heo, Jeong Soon; Kim, Wooseong; Jung, Yunjin; Kim, Young Mi

    2014-02-01

    To develop a polymer matrix for controlled release of drugs, chitosan, a linear aminopolysaccharide, was chemically modified to dithiocarbamate chitosan (DTCC) to afford a matrix where metal-drug complexes could be attached and released in a controlled manner depending on the binding nature between the drugs and the metals. DTCC was treated with metal-tetracycline (Tc) complexes to prepare DTCC-Ca(II)-Tc, DTCC-Mg(II)-Tc, DTCC-Cu(II)-Tc and DTCC-Zn(II)-Tc. The binding amount of Tc was in the order of DTCC-Zn(II)-Tc ≈ DTCC-Mg(II)-Tc ≈  DTCC-Ca(II)-Tc > DTCC-Cu(II)-Tc. The biphasic binding profiles, where Tc binding increased initially and then decreased, were shown for DTCC-Cu(II)-Tc and DTCC-Zn(II)-Tc. In a flow method, Tc was released slowly from DTCC-metal-Tc complexes except for DTCC-Cu(II)-Tc compared with Tc release from DTCC-Tc. In parallel with the results of the release experiment, DTCC-metal-Tc complexes except for DTCC-Cu(II)-Tc presented a prolonged antibacterial activity in an antibacterial test. The antibacterial activity of DTCC-Ca(II)-, -Mg(II)- and -Zn(II)-Tc complexes lasted for 28-44 days, while free Tc and DTCC-Tc lasted for 7-12 days. Taken together, our data suggest that DTCC could be used for a polymeric matrix for controlled release of drugs such as Tc, which possess functional groups for ionic and/or coordinate bond with metals.

  10. Nanoparticle-Enabled Transdermal Drug Delivery Systems for Enhanced Dose Control and Tissue Targeting

    Directory of Open Access Journals (Sweden)

    Brian C. Palmer

    2016-12-01

    Full Text Available Transdermal drug delivery systems have been around for decades, and current technologies (e.g., patches, ointments, and creams enhance the skin permeation of low molecular weight, lipophilic drugs that are efficacious at low doses. The objective of current transdermal drug delivery research is to discover ways to enhance skin penetration of larger, hydrophilic drugs and macromolecules for disease treatment and vaccination. Nanocarriers made of lipids, metals, or polymers have been successfully used to increase penetration of drugs or vaccines, control drug release, and target drugs to specific areas of skin in vivo. While more research is needed to identify the safety of nanocarriers, this technology has the potential to expand the use of transdermal routes of administration to a wide array of therapeutics. Here, we review the current state of nanoparticle skin delivery systems with special emphasis on targeting skin diseases.

  11. Recent Advances in the Synthesis of Graphene-Based Nanomaterials for Controlled Drug Delivery

    Directory of Open Access Journals (Sweden)

    Zhuqing Wang

    2017-11-01

    Full Text Available Graphene-based nanomaterials have exhibited wide applications in nanotechnology, materials science, analytical science, and biomedical engineering due to their unique physical and chemical properties. In particular, graphene has been an excellent nanocarrier for drug delivery application because of its two-dimensional structure, large surface area, high stability, good biocompatibility, and easy surface modification. In this review, we present the recent advances in the synthesis and drug delivery application of graphene-based nanomaterials. The modification of graphene and the conjugation of graphene with other materials, such as small molecules, nanoparticles, polymers, and biomacromolecules as functional nanohybrids are introduced. In addition, the controlled drug delivery with the fabricated graphene-based nanomaterials are demonstrated in detail. It is expected that this review will guide the chemical modification of graphene for designing novel functional nanohybrids. It will also promote the potential applications of graphene-based nanomaterials in other biomedical fields, like biosensing and tissue engineering.

  12. Intelligent "Peptide-Gathering Mechanical Arm" Tames Wild "Trojan-Horse" Peptides for the Controlled Delivery of Cancer Nanotherapeutics.

    Science.gov (United States)

    Shi, Nian-Qiu; Li, Yan; Zhang, Yong; Shen, Nan; Qi, Ling; Wang, Shu-Ran; Qi, Xian-Rong

    2017-12-06

    Cell-penetrating peptides (CPPs), also called "Trojan-Horse" peptides, have been used for facilitating intracellular delivery of numerous diverse cargoes and even nanocarriers. However, the lack of targeting specificity ("wildness" or nonselectivity) of CPP-nanocarriers remains an intractable challenge for many in vivo applications. In this work, we used an intelligent "peptide-gathering mechanical arm" (Int PMA) to curb CPPs' wildness and enhance the selectivity of R 9 -liposome-based cargo delivery for tumor targeting. The peptide NGR, serving as a cell-targeting peptide for anchoring, and peptide PLGLAG, serving as a substrate peptide for deanchoring, were embedded in the Int PMA motif. The Int PMA construct was designed to be sensitive to tumor microenvironmental stimuli, including aminopeptidase N (CD13) and matrix metalloproteinases (MMP-2/9). Moreover, Int PMA could be specifically recognized by tumor tissues via CD13-mediated anchoring and released for cell entry by MMP-2/9-mediated deanchoring. To test the Int PMA design, a series of experiments were conducted in vitro and in vivo. Functional conjugates Int PMA-R 9 -poly(ethylene glycol) (PEG) 2000 -distearoylphosphatidyl-ethanolamine (DSPE) and R 9 -PEG 2000 -DSPE were synthesized by Michael addition reaction and were characterized by thin-layer chromatography and matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. The Int PMA-R 9 -modified doxorubicin-loaded liposomes (Int PMA-R 9 -Lip-DOX) exhibited a proper particle diameter (approximately 155 nm) with in vitro sustained release characteristics. Cleavage assay showed that Int PMA-R 9 peptide molecules could be cleaved by MMP-2/9 for completion of deanchoring. Flow cytometry and confocal microscopy studies indicated that Int PMA-R 9 -Lip-DOX can respond to both endogenous and exogenous stimuli in the presence/absence of excess MMP-2/9 and MMP-2/9 inhibitor (GM6001) and effectively function under competitive receptor

  13. STUDIES ON NATURAL AND SYNTHETIC POLYMERS FOR CONTROLLED RELEASE MATRIX TABLET OF ACECLOFENAC

    OpenAIRE

    Abhishek S. Joshi *, Deepak A. Joshi , Avinash V. Dhobale , Sandhya S. Bundel , Vijay R. Chakote, Gunesh N. Dhembre

    2018-01-01

    The present study was aimed to design new oral controlled release matrix tablets of new NSAID Aceclofenac for once a day by using 10, 15, 20 and 25% of GG:HPMC and XG:HPMC mixture in the ratio 1:1 by wet granulation method. The prepared tablets subjected to in vitro drug release studies in pH 7.4 buffer solution. All the formulation meets the pre-compression and compression characteristics. All the tablets prepared with 10, 15, 20 and 25% of HPMC: XG mixture in the ratio 1:1 fails to meet the...

  14. Determinant factors of home delivery among women in Northern Ethiopia: a case control study

    Directory of Open Access Journals (Sweden)

    Resom Tsegay

    2017-04-01

    Full Text Available Abstract Background Maternal mortality remains a major challenge to health systems worldwide. Although most pregnancies and births are uneventful, approximately 15% of all pregnant women develop potentially life-threatening complications. Home delivery in this context can be acutely threatening, particularly in developing countries where emergency care and transportation are less available. This study identifies factors associated with home delivery in Tanqua-Abergele District, Tigray, northern Ethiopia. Methods Unmatched case-control study was conducted in April 2014 in Tanqua-Abergele, Tigray, northern Ethiopia. Simple random sampling was employed to select study participants. Data were analyzed using SPSS 20. Multi variable logistic regression analysis was used to identify independent predictors of home delivery. Results A total of 275 women (92 cases and 183 controls participated in the study, giving a response rate of 96.5%. Not owning a radio or television (AOR: 7.2, 95% CI: 2.7–19.3, not pursuing ANC visits at all (AOR: 10.4, 95% CI: 2.9–37.1 orhaving1–3 ANC visits only (AOR: 4.75, 95% CI: 1.69–13.31,poor knowledge of obstetric complications (AOR: 8.7, 95% CI: 2.3–32.9 and walking time greater than two hours to the nearest health center (AOR: 5.1, 95% CI: 1.2–20.7 were strong predictors of home delivery. Conclusion Unable to meet the minimum requirement WHO of ANC service had a potential to give birth at home. Investing in infrastructure will contribute to improving maternal health. Having a different source of media (radio or television could have a role in increasing the institutional delivery. Policy makers and other concerned bodies should give due attention to the fulfillment of infrastructure and educate women on the importance of institutional delivery.

  15. A current controlled matrix converter for wind energy conversion systems based on permanent magnet synchronous generator

    Directory of Open Access Journals (Sweden)

    Naggar H. Saad

    2016-05-01

    Full Text Available The main challenges of wind energy conversion systems (WECS are to maximize the energy capture from the wind and injecting reactive power during the fault. This paper presents a current controlled matrix converter to interface Permanent Magnet Synchronous Generators (PMSG based WECS with the grid. To achieve fast dynamic response with reduced current ripples, a hysteresis current control is utilized. The proposed control system decouples the active and reactive components of the PMSG current to extract the maximum power from the wind at a given wind velocity and to inject reactive power to the grid. Reactive power injection during the fault satisfying the grid-codes requirement. The proposed WECS has been modeled and simulated using PSCAD/EMTDC software package.

  16. Linear matrix inequality approach for synchronization control of fuzzy cellular neural networks with mixed time delays

    International Nuclear Information System (INIS)

    Balasubramaniam, P.; Kalpana, M.; Rakkiyappan, R.

    2012-01-01

    Fuzzy cellular neural networks (FCNNs) are special kinds of cellular neural networks (CNNs). Each cell in an FCNN contains fuzzy operating abilities. The entire network is governed by cellular computing laws. The design of FCNNs is based on fuzzy local rules. In this paper, a linear matrix inequality (LMI) approach for synchronization control of FCNNs with mixed delays is investigated. Mixed delays include discrete time-varying delays and unbounded distributed delays. A dynamic control scheme is proposed to achieve the synchronization between a drive network and a response network. By constructing the Lyapunov—Krasovskii functional which contains a triple-integral term and the free-weighting matrices method an improved delay-dependent stability criterion is derived in terms of LMIs. The controller can be easily obtained by solving the derived LMIs. A numerical example and its simulations are presented to illustrate the effectiveness of the proposed method. (interdisciplinary physics and related areas of science and technology)

  17. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Science.gov (United States)

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert

    2016-01-12

    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  18. Differential impact of the cheese matrix on the postprandial lipid response: a randomized, crossover, controlled trial.

    Science.gov (United States)

    Drouin-Chartier, Jean-Philippe; Tremblay, André J; Maltais-Giguère, Julie; Charest, Amélie; Guinot, Léa; Rioux, Laurie-Eve; Labrie, Steve; Britten, Michel; Lamarche, Benoît; Turgeon, Sylvie L; Couture, Patrick

    2017-12-01

    Background: In a simulated gastrointestinal environment, the cheese matrix modulates dairy fat digestion. However, to our knowledge, the impact of the cheese matrix on postprandial lipemia in humans has not yet been evaluated. Objective: In healthy subjects, we compared the impact of dairy fat provided from firm cheese, soft cream cheese, and butter on the postprandial response at 4 h and on the incremental area under the curve (iAUC) of plasma triglycerides. Design: Forty-three healthy subjects were recruited to this randomized, crossover, controlled trial. In random order at intervals of 14 d and after a 12-h fast, subjects ingested 33 g fat from a firm cheese (young cheddar), a soft cream cheese (cream cheese), or butter (control) incorporated into standardized meals that were matched for macronutrient content. Plasma concentrations of triglycerides were measured immediately before the meal and 2, 4, 6, and 8 h after the meal. Results: Cheddar cheese, cream cheese, and butter induced similar increases in triglyceride concentrations at 4 h (change from baseline: +59%, +59%, and +62%, respectively; P = 0.9). No difference in the triglyceride iAUC 0-8 h ( P -meal = 0.9) was observed between the 3 meals. However, at 2 h, the triglyceride response caused by the cream cheese (change from baseline: +44%) was significantly greater than that induced by butter (change from baseline: +24%; P = 0.002) and cheddar cheese (change from baseline: +16%; P = 0.0004). At 6 h, the triglyceride response induced by cream cheese was significantly attenuated compared with that induced by cheddar cheese (change from baseline: +14% compared with +42%; P = 0.0004). Conclusion: This study demonstrates that the cheese matrix modulates the impact of dairy fat on postprandial lipemia in healthy subjects. This trial was registered at clinicaltrials.gov as NCT02623790. © 2017 American Society for Nutrition.

  19. Controlled delivery of ropinirole hydrochloride through skin using modulated iontophoresis and microneedles.

    Science.gov (United States)

    Singh, Neha D; Banga, Ajay K

    2013-05-01

    The objective of this study was to investigate the effect of modulated current application using iontophoresis- and microneedle-mediated delivery on transdermal permeation of ropinirole hydrochloride. AdminPatch® microneedles and microchannels formed by them were characterized by scanning electron microscopy, dye staining and confocal microscopy. In vitro permeation studies were carried out using Franz diffusion cells, and skin extraction was used to quantify drug in underlying skin. Effect of microneedle pore density and ions in donor formulation was studied. Active enhancement techniques, continuous iontophoresis (74.13 ± 2.20 µg/cm(2)) and microneedles (66.97 ± 10.39 µg/cm(2)), significantly increased the permeation of drug with respect to passive delivery (8.25 ± 2.41 µg/cm(2)). Modulated iontophoresis could control the amount of drug delivered at a given time point with the highest flux being 5.12 ± 1.70 µg/cm(2)/h (5-7 h) and 5.99 ± 0.81 µg/cm(2)/h (20-22 h). Combination of modulated iontophoresis and microneedles (46.50 ± 6.46 µg/cm(2)) showed significantly higher delivery of ropinirole hydrochloride compared to modulated iontophoresis alone (84.91 ± 9.21 µg/cm(2)). Modulated iontophoresis can help in maintaining precise control over ropinirole hydrochloride delivery for dose titration in Parkinson's disease therapy and deliver therapeutic amounts over a suitable patch area and time.

  20. Mesoporous silica nanoparticles for stimuli-responsive controlled drug delivery: advances, challenges, and outlook

    Directory of Open Access Journals (Sweden)

    Song Y

    2016-12-01

    Full Text Available Yuanhui Song, Yihong Li, Qien Xu, Zhe Liu Wenzhou Institute of Biomaterials and Engineering (WIBE, Wenzhou Medical University, Wenzhou, Zhejiang, People’s Republic of China Abstract: With the development of nanotechnology, the application of nanomaterials in the field of drug delivery has attracted much attention in the past decades. Mesoporous silica nanoparticles as promising drug nanocarriers have become a new area of interest in recent years due to their unique properties and capabilities to efficiently entrap cargo molecules. This review describes the latest advances on the application of mesoporous silica nanoparticles in drug delivery. In particular, we focus on the stimuli-responsive controlled release systems that are able to respond to intracellular environmental changes, such as pH, ATP, GSH, enzyme, glucose, and H2O2. Moreover, drug delivery induced by exogenous stimuli including temperature, light, magnetic field, ultrasound, and electricity is also summarized. These advanced technologies demonstrate current challenges, and provide a bright future for precision diagnosis and treatment. Keywords: mesoporous silica nanoparticle, drug delivery system, controlled release, stimuli-responsive, chemotherapy

  1. Nanotechnology-based polymeric bio(muco)adhesive platforms for controlling drug delivery - properties, methodologies and applications

    International Nuclear Information System (INIS)

    Carvalho, Flavia Chiva; Chorilli, Marlus; Gremiao, Maria Palmira Daflon

    2014-01-01

    Studies using bio(muco)adhesive drug delivery systems have recently gained great interest, which can promote drug targeting and more specific contact of the drug delivery system with the various absorptive membranes of the body. This technological platform associated with nanotechnology offers potential for controlling drug delivery; therefore, they are excellent strategies to increase the bioavailability of drugs. The objective of this work was to study nanotechnology-based polymeric bio(muco)adhesive platforms for controlling drug delivery, highlighting their properties, how the bio(muco)adhesion can be measured and their potential applications for different routes of administration. (author)

  2. Development of span 80-tween 80 based fluid-filled organogels as a matrix for drug delivery

    Directory of Open Access Journals (Sweden)

    Charulata Bhattacharya

    2012-01-01

    Full Text Available Background: Organogels are defined as 3-dimensional networked structures which immobilize apolar solvents within them. These gelled formulations are gaining importance because of their ease of preparation and inherent stability with improved shelf life as compared to the ointments. Aim: Development of span 80-tween 80 mixture based organogels for the first time by fluid-filled fiber mechanism. Materials and Methods: Span 80 and tween 80 were used as surfactant and co-surfactant, respectively. The surfactant mixtures were dissolved in oil followed by the addition of water which led to the formation of organogels at specific compositions. The formulations were analyzed by microscopy, X-ray diffraction (XRD, time-dependent stability test and accelerated thermal stability test by thermocycling method. Ciprofloxacin, a fourth-generation fluoroquinolone, was incorporated within the organogels. The antimicrobial activity of the drug loaded organogels and in vitro drug release from the gels was also determined. Results and Conclusions: Microscopic results indicated that the gels contained clusters of water-filled spherical structures. XRD study indicated the amorphous nature of the organogels. The release of the drug was found to be diffusion controlled and showed marked antimicrobial property. In short, the prepared organogels were found to be stable enough to be used as pharmaceutical formulation.

  3. Open-Switch Fault Diagnosis and Fault Tolerant for Matrix Converter with Finite Control Set-Model Predictive Control

    DEFF Research Database (Denmark)

    Peng, Tao; Dan, Hanbing; Yang, Jian

    2016-01-01

    To improve the reliability of the matrix converter (MC), a fault diagnosis method to identify single open-switch fault is proposed in this paper. The introduced fault diagnosis method is based on finite control set-model predictive control (FCS-MPC), which employs a time-discrete model of the MC...... topology and a cost function to select the best switching state for the next sampling period. The proposed fault diagnosis method is realized by monitoring the load currents and judging the switching state to locate the faulty switch. Compared to the conventional modulation strategies such as carrier......-switch fault conditions without any redundant hardware, a fault tolerant strategy based on predictive control is also studied. The fault tolerant strategy is to select the most appropriate switching state, associated with the remaining normal switches of the MC. Experiment results are presented to show...

  4. Benefits of repeated individual dietary counselling in long-term weight control in women after delivery.

    Science.gov (United States)

    Jaakkola, Johanna; Isolauri, Erika; Poussa, Tuija; Laitinen, Kirsi

    2015-10-01

    As pregnancy may trigger overweight in women, new means for its prevention are being sought. The aim here was to investigate the effect of individual dietary counselling during and after pregnancy on post-partum weight and waist circumference up to 4 years post-partum. A cohort of women (n = 256) were randomized to receive repeated individual dietary counselling by a nutritionist during and after pregnancy, or as controls not receiving dietary counselling, from the first trimester of pregnancy until 6 months after delivery. Counselling aimed to bring dietary intake into line with recommendations, with particular focus on the increase in the intake of unsaturated fatty acids instead of saturated. Pre-pregnancy weight was taken from welfare clinic records. Weight and waist circumference were measured at 4 years after delivery. The proportion of overweight women increased from 26% prior to pregnancy to 30% at 4 years after delivery among women receiving dietary counselling, as against considerably more, from 32% to 57%, among controls. The prevalence of central adiposity was 31% in women receiving dietary counselling, 64% in controls. Likewise, both the risk of overweight (odds ratio: 0.23, 0.08-0.63, P = 0.005) and central adiposity (odds ratio: 0.18, 0.06-0.52, P = 0.002) were lower in women receiving dietary counselling compared with controls. Repeated dietary counselling initiated in early pregnancy can be beneficial in long-term weight control after delivery. © 2014 John Wiley & Sons Ltd.

  5. Drug release control in delivery system for biodegradable polymer drugs by γ-radiation

    International Nuclear Information System (INIS)

    Yoshioka, Sumie; Azo, Yukio; Kojima, Shigeo

    1997-01-01

    Characterizations of the drug release from microsphere and hydrogel preparation made from biodegradable polymers were investigated aiming at development of a drug delivery system which allows an optimum drug delivery and the identification of the factors which control its delivery. Poly-lactic acid microspheres containing 10% of progesterone were produced from poly DL-lactic acid and exposed to γ-ray at 5-1000 kGy. And its glass transition temperature (Tg) was determined by differential scanning calorimetry. The temperature was gradually lowered with an increase in the dose of radiation. Tg of the microsphere exposed at 1000 kGy was lower by 10degC compared with the untreated one, showing that Tg control is possible without changing the size distribution of microsphere. Then, the amount of progesterone released from microsphere was determined. The release rate of the drug linearly increased with a square root of radiation time. These results indicate that the control of drug release rate is possible through controling the microsphere's Tg by γ-ray radiation. (M.N.)

  6. Controlled local drug delivery strategies from chitosan hydrogels for wound healing.

    Science.gov (United States)

    Elviri, Lisa; Bianchera, Annalisa; Bergonzi, Carlo; Bettini, Ruggero

    2017-07-01

    The main target of tissue engineering is the preparation and application of adequate materials for the design and production of scaffolds, that possess properties promoting cell adhesion, proliferation and differentiation. The use of natural polysaccharides, such as chitosan, to prepare hydrogels for wound healing and controlled drug delivery is a research topic of wide and increasing interest. Areas covered: This review presents the latest results and challenges in the preparation of chitosan and chitosan-based scaffold/hydrogel for wound healing applications. A detailed overview of their behavior in terms of controlled drug delivery, divided by drug categories, and efficacy was provided and critically discussed. Expert opinion: The need to establish and exploit the advantages of natural biomaterials in combination with active compounds is playing a pivotal role in the regenerative medicine fields. The challenges posed by the many variables affecting tissue repair and regeneration need to be standardized and adhere to recognized guidelines to improve the quality of evidence in the wound healing process. Currently, different methodologies are followed to prepare innovative scaffold formulations and structures. Innovative technologies such as 3D printing or bio-electrospray are promising to create chitosan-based scaffolds with finely controlled structures with customizable shape porosity and thickness. Chitosan scaffolds could be designed in combination with a variety of polysaccharides or active compounds with selected and reproducible spacial distribution, providing active wound dressing with highly tunable controlled drug delivery.

  7. Formulation and evaluation of controlled release matrix mucoadhesive tablets of domperidone using Salvia plebeian gum

    Directory of Open Access Journals (Sweden)

    Gurpreet Arora

    2011-01-01

    Full Text Available The aim of study was to prepare controlled release matrix mucoadhesive tablets of domperidone using Salvia plebeian gum as natural polymer. Tablets were formulated by direct compression technology employing the natural polymer in different concentrations (5, 10, 15 and 20% w/w. The prepared batches were evaluated for drug assay, diameter, thickness, hardness and tensile strength, swelling index, mucoadhesive strength (using texture analyzer and subjected to in vitro drug release studies. Real-time stability studies were also conducted on prepared batches. In vitro drug release data were fitted in various release kinetic models for studying the mechanism of drug release. Tensile strength was found to increase from 0.808 ± 0.098 to 1.527 ± 0.10 mN/cm 2 and mucoadhesive strength increased from 13.673 ± 1.542 to 40.378 ± 2.345 N, with an increase in the polymer concentration from 5 to 20% (A1 to A4. Swelling index was reported to increase with both increase in the concentration of gum and the time duration. The in vitro drug release decreased from 97.76 to 83.4% (A1 to A4 with the increase in polymer concentration. The drug release from the matrix tablets was found to follow zero-order and Higuchi models, indicating the matrix-forming potential of natural polymer. The value of n was found to be between 0.5221 and 0.8992, indicating the involvement of more than one drug release mechanism from the formulation and possibly the combination of both diffusion and erosion. These research findings clearly indicate the potential of S. plebeian gum to be used as binder, release retardant and mucoadhesive natural material in tablet formulations.

  8. A controlled and sustained local gentamicin delivery system for inner ear applications.

    Science.gov (United States)

    Xu, Lei; Heldrich, Jonna; Wang, Haibo; Yamashita, Taku; Miyamoto, Shunsuke; Li, Andrew; Uboh, Cornelius E; You, Youwen; Bigelow, Douglas; Ruckenstein, Michael; O'Malley, Bert; Li, Daqing

    2010-09-01

    Intratympanic gentamicin injection (ITGI) has gained acceptance worldwide for the treatment of Ménière's disease. Reports assessing the efficacy of ITGI suffer from high variability between patients. This variability may be due to ITGI, which does not permit a sustained diffusion of gentamicin across the round window membrane. The present study investigates the effectiveness of a sustained local hydrogel system on the delivery of gentamicin into the inner ear for the treatment of Ménière's disease. A matrix of hydrogel loaded with/without gentamicin was explored in vivo. Gentamicin was applied to the ear of mice either through ITGI or in the hydrogel system. Pharmacokinetics, hearing, and balance function were examined to study how the hydrogel system affected the gentamicin delivery and inner ear functions. The 2 gentamicin delivery methods yielded different kinetics curves. The hydrogel system achieved sustained release during a 7-day period, with a flat plateau phase from Day 1 to Day 3 and slow descent in the subsequent days. The ITGI curve dramatically declined after the peak concentration at Day 1 and was almost eliminated by Day 3. The hydrogel system yielded noticeable balance dysfunction with no significant hearing changes. In contrast, ITGI exhibited no significant influences on the inner ear functions after applying the same dose of 40 kg of gentamicin. The hydrogel system established in this research allows for more sustained and consistent and efficient drug release than traditional ITGI for the transport of gentamicin into the inner ear, offering a new and exciting treatment of Ménière's disease.

  9. Preparation and Characterization of Silver Doped Hydroxyapatite Scaffolds with Chitosan for Controlled Drug Delivery

    OpenAIRE

    Dubņika, A; Loča, D; Bērziņa-Cimdiņa, L

    2012-01-01

    Silver doped hydroxyapatite (HAp/Ag) is a promising biomaterial for hard tissue regeneration due to the silver antibacterial properties and hydroxyapatite osteoconductivity, bioactivity and biocompatibility. The main advantages of HAp/Ag materials for controlled drug delivery are their antibacterial properties and constant and continuous drug levels with limited side effects. Chitosan was chosen because it’s ecologically safe biopolymer and it contains amino and hydroxyl groups...

  10. A Journey to Improved Inpatient Glycemic Control by Redesigning Meal Delivery and Insulin Administration.

    Science.gov (United States)

    Engle, Martha; Ferguson, Allison; Fields, Willa

    2016-01-01

    The purpose of this quality improvement project was to redesign a hospital meal delivery process in order to shorten the time between blood glucose monitoring and corresponding insulin administration and improve glycemic control. This process change redesigned the workflow of the dietary and nursing departments. Modifications included nursing, rather than dietary, delivering meal trays to patients receiving insulin. Dietary marked the appropriate meal trays and phoned each unit prior to arrival on the unit. The process change was trialed on 2 acute care units prior to implementation hospital wide. Elapsed time between blood glucose monitoring and insulin administration was analyzed before and after process change as well as evaluation of glucometrics: percentage of patients with blood glucose between 70 and 180 mg/dL (percent perfect), blood glucose greater than 300 mg/dL (extreme hyperglycemia), and blood glucose less than 70 mg/dL (hypoglycemia). Percent perfect glucose results improved from 45% to 53%, extreme hyperglycemia (blood glucose >300 mg/dL) fell from 11.7% to 5%. Hypoglycemia demonstrated a downward trend line, demonstrating that with improving glycemic control hypoglycemia rates did not increase. Percentage of patients receiving meal insulin within 30 minutes of blood glucose check increased from 35% to 73%. In the hospital, numerous obstacles were present that interfered with on-time meal insulin delivery. Establishing a meal delivery process with the nurse performing the premeal blood glucose check, delivering the meal, and administering the insulin improves overall blood glucose control. Nurse-led process improvement of blood glucose monitoring, meal tray delivery, and insulin administration does lead to improved glycemic control for the inpatient population.

  11. Fabrication of chitosan-g-poly(acrylamide)/CuS nanocomposite for controlled drug delivery and antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Pathania, Deepak, E-mail: dpathania74@gmail.com [School of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan, H.P. (India); Gupta, Divya [School of Chemistry, Shoolini University of Biotechnology and Management Sciences, Solan, H.P. (India); Agarwal, Shilpi [Department of Applied Chemistry, University of Johannesburg, Johannesburg (South Africa); Asif, M. [Chemical Engineering Department, King Suad University Riyadh (Saudi Arabia); Gupta, Vinod Kumar [Department of Applied Chemistry, University of Johannesburg, Johannesburg (South Africa); Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee, 247667 (India)

    2016-07-01

    In present study, we reported the synthesis of chitosan-g-poly(acrylamide)/CuS (CPA/CS) nanocomposite for controlled delivery of ofloxacin. The CPA/CS nanocomposites were characterized by Fourier transmission infrared spectroscopy (FTIR), UV–visible spectroscopy (UV), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis. From the FTIR spectra, the various groups present in CPA/CS nanocomposite were monitored. The homogeneity, morphology and crystallinity of the CPA/CS nanocomposite were ascertained from SEM/EDX and XRD data, respectively. The kinetics of ofloxacin drug delivery was investigated at different pH. The drug released studies were investigated at different pH (2.2, 7.4 and 9.4) and time intervals (2, 4, 6, 8, 10, 12, 14, 16 h). The drug release behavior depends upon the pH of medium and the nature of matrix. The maximum drug loading efficiency of 85% was recorded for CPA/CS. The maximum drug release of 76% was observed at 2.2. pH after 18 h onto CPA/CS. Nanocomposites were also tested for antibacterial activity against Escherichia coli bacteria. About 97% killing of E. coli was observed after 24 h. - Highlights: • Chitosan-g-poly(acrylamide)/CuS (CPA/CS) nanocomposite has been synthesized in microwave reactor. • Different spectral techniques confirmed the formation of nanocomposite. • The drug release behavior of CPA/CS nanocomposites were studied at different pH and different time interval. • CPA/CS has been investigated for an excellent antibacterial activity against E. coli bacterial culture.

  12. PREPARATION OF GLIMEPIRIDE ALOE BARBADENSIS MILLER LEAVES MUCILAGE AND POVIDONE CONTROLLED RELEASE MATRIX TABLETS: IN VITRO AND IN VIVO EVALUATION

    OpenAIRE

    Hindustan Abdul Ahad; Sreeramulu J; Hima Bindu V; Guru Prakash P; Sravanthi M

    2011-01-01

    The main purpose of the present study was to prepare Glimepiride matrix tablets with Aloe barbadensis miller leaves mucilage and Povidone and to study its novelty as a matrix forming polymer for controlled release tablet formulations. Physicochemical properties of the dried powdered Aloe barbadensis miller mucilage and Povidone blend, drug-excipient compatibility studies, pre formulation studies, post formulation studies, in vitro drug release studies, mathematical modeling of in vitro dissol...

  13. Phase sensitive control of vibronic guest-host interaction: Br2 in Ar matrix.

    Science.gov (United States)

    Ibrahim, Heide; Héjjas, Mónika; Fushitani, Mizuho; Schwentner, Nikolaus

    2009-07-02

    Vibronic progressions are programmed into a pulse shaper which converts them via the inherent Fourier transformation into a train of femtosecond pulses in time domain for chromophore excitation. Double pulse results agree with phase-sensitive wave packet superposition from a Michelson interferometer which delivers coherence times with high reliability. Spectral resolution of 1 nm and a spacing of around 4 nm within the 20 nm envelope centered at 590 nm delivers a train of seven phase-controlled 40 fs subpulses separated by 250 fs. Combs adjusted to the zero phonon lines (ZPL) and phonon sidebands (PSB) of the B state vibronic progression are reproduced in the chromophore for a coherent subpulse accumulation. B state ZPL wave packet dynamics dominates in pump-probe spectra due to its coherence despite an overwhelming but incoherent A state contribution in absorption. PSB comb accumulation is also phase sensitive and demonstrates coherence within several 100 matrix degrees of freedom in the vicinity.

  14. Design, Characterization, and Optimization of Controlled Drug Delivery System Containing Antibiotic Drug/s.

    Science.gov (United States)

    Patel, Apurv; Dodiya, Hitesh; Shelate, Pragna; Shastri, Divyesh; Dave, Divyang

    2016-01-01

    The objective of this work was design, characterization, and optimization of controlled drug delivery system containing antibiotic drug/s. Osmotic drug delivery system was chosen as controlled drug delivery system. The porous osmotic pump tablets were designed using Plackett-Burman and Box-Behnken factorial design to find out the best formulation. For screening of three categories of polymers, six independent variables were chosen for Plackett-Burman design. Osmotic agent sodium chloride and microcrystalline cellulose, pore forming agent sodium lauryl sulphate and sucrose, and coating agent ethyl cellulose and cellulose acetate were chosen as independent variables. Optimization of osmotic tablets was done by Box-Behnken design by selecting three independent variables. Osmotic agent sodium chloride, pore forming agent sodium lauryl sulphate, and coating agent cellulose acetate were chosen as independent variables. The result of Plackett-Burman and Box-Behnken design and ANOVA studies revealed that osmotic agent and pore former had significant effect on the drug release up to 12 hr. The observed independent variables were found to be very close to predicted values of most satisfactory formulation which demonstrates the feasibility of the optimization procedure in successful development of porous osmotic pump tablets containing antibiotic drug/s by using sodium chloride, sodium lauryl sulphate, and cellulose acetate as key excipients.

  15. Design, Characterization, and Optimization of Controlled Drug Delivery System Containing Antibiotic Drug/s

    Directory of Open Access Journals (Sweden)

    Apurv Patel

    2016-01-01

    Full Text Available The objective of this work was design, characterization, and optimization of controlled drug delivery system containing antibiotic drug/s. Osmotic drug delivery system was chosen as controlled drug delivery system. The porous osmotic pump tablets were designed using Plackett-Burman and Box-Behnken factorial design to find out the best formulation. For screening of three categories of polymers, six independent variables were chosen for Plackett-Burman design. Osmotic agent sodium chloride and microcrystalline cellulose, pore forming agent sodium lauryl sulphate and sucrose, and coating agent ethyl cellulose and cellulose acetate were chosen as independent variables. Optimization of osmotic tablets was done by Box-Behnken design by selecting three independent variables. Osmotic agent sodium chloride, pore forming agent sodium lauryl sulphate, and coating agent cellulose acetate were chosen as independent variables. The result of Plackett-Burman and Box-Behnken design and ANOVA studies revealed that osmotic agent and pore former had significant effect on the drug release up to 12 hr. The observed independent variables were found to be very close to predicted values of most satisfactory formulation which demonstrates the feasibility of the optimization procedure in successful development of porous osmotic pump tablets containing antibiotic drug/s by using sodium chloride, sodium lauryl sulphate, and cellulose acetate as key excipients.

  16. Nanoscaffold matrices for size-controlled, pulsatile transdermal testosterone delivery: nanosize effects on the time dimension

    Science.gov (United States)

    Malik, Ritu; Tondwal, Shailesh; Venkatesh, K. S.; Misra, Amit

    2008-10-01

    Pulsatile transdermal testosterone (T) has applications in hormone supplementation and male contraception. Pulsatile T delivery was achieved by assembling crystalline and nanoparticulate T in nucleation-inhibiting polymer matrices of controlled porosity. Different interference patterns observed from various polymeric films containing T were due to the various particle sizes of T present in the polymer matrices. Scanning electron microscopy was used to determine the size and shape of T crystals. Skin-adherent films containing T nanoparticles of any size between 10-500 nm could be prepared using pharmaceutically acceptable vinylic polymers. Drug release and skin permeation profiles were studied. The dissolution-diffusion behavior of nanoparticles differed from crystalline and molecular states. Nanosize may thus be used to engineer chronopharmacologically relevant drug delivery.

  17. Optical separation and controllable delivery of cells from particle and cell mixture

    Directory of Open Access Journals (Sweden)

    Li Yuchao

    2015-11-01

    Full Text Available Cell separation and delivery have recently gained significant attention in biological and biochemical studies. In thiswork, an optical method for separation and controllable delivery of cells by using an abruptly tapered fiber probe is reported. By launching a laser beam at the wavelength of 980 nm into the fiber, a mixture of cells with sizes of ~5 and ~3 μm and poly(methyl methacrylate particles with size of 5 μm are separated into three chains along the direction of propagation of light. The cell and particle chains are delivered in three dimensions over 600 μm distance. Experimental results are interpreted by numerical simulations. Optical forces and forward migration velocities of different particles and cells are calculated and discussed.

  18. Modified tamarind kernel polysaccharide: a novel matrix for control release of aspirin.

    Science.gov (United States)

    Ghosh, Sandipta; Pal, Sagar

    2013-07-01

    pH dependent hydrogels of modified tamarind kernel polysaccharide (TKP) were synthesized by grafting with polyacrylamide chains on TKP backbone in presence of microwave irradiation and initiator. The present study is carried out to design oral controlled drug delivery systems for aspirin using synthesized hydrogels as carrier in form of tablets. TKP-g-PAM based hydrogels show significant enhancement for control release of aspirin. Release behavior of aspirin has been evaluated using USP type I apparatus in 900 mL of buffer solutions (pH 1.2, 6.8, 7.4), maintained at 37°C at 100 rpm. It is observed that with increase in percentage of grafting (% G), swelling of matrices increases whereas erosion and rate of drug release decrease. The effect of % G onto t50 value (time taken for release of 50% drug) has also been discussed. The release characteristics from the matrices under study show non-Fickian diffusion mechanism, suggesting the controlled release of aspirin. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Natural material-decorated mesoporous silica nanoparticle container for multifunctional membrane-controlled targeted drug delivery

    Directory of Open Access Journals (Sweden)

    Hu Y

    2017-11-01

    Full Text Available Yan Hu,1 Lei Ke,2 Hao Chen,1 Ma Zhuo,1 Xinzhou Yang,1 Dan Zhao,1 Suying Zeng,1 Xincai Xiao1 1Department of Pharmaceutics, School of Pharmaceutical Science, South-Central University for Nationalities, 2Department of Medicinal Chemistry, School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China Abstract: To avoid the side effects caused by nonspecific targeting, premature release, weak selectivity, and poor therapeutic efficacy of current nanoparticle-based systems used for drug delivery, we fabricated natural material-decorated nanoparticles as a multifunctional, membrane-controlled targeted drug delivery system. The nanocomposite material coated with a membrane was biocompatible and integrated both specific tumor targeting and responsiveness to stimulation, which improved transmission efficacy and controlled drug release. Mesoporous silica nanoparticles (MSNs, which are known for their biocompatibility and high drug-loading capacity, were selected as a model drug container and carrier. The membrane was established by the polyelectrolyte composite method from chitosan (CS which was sensitive to the acidic tumor microenvironment, folic acid-modified CS which recognizes the folate receptor expressed on the tumor cell surface, and a CD44 receptor-targeted polysaccharide hyaluronic acid. We characterized the structure of the nanocomposite as well as the drug release behavior under the control of the pH-sensitive membrane switch and evaluated the antitumor efficacy of the system in vitro. Our results provide a basis for the design and fabrication of novel membrane-controlled nanoparticles with improved tumor-targeting therapy. Keywords: multifunctional, membrane-controlled, natural materials, mesoporous silica nanoparticles, targeted drug delivery

  20. The First Government Sanctioned Delivery of Medical Supplies by Remotely Controlled Unmanned Aerial System (UAS)

    Science.gov (United States)

    Howell, Charles T., III; Jones, Frank; Thorson, Taylor; Grube, Richard; Mellanson, Cecil; Joyce, Lee; Coggin, John; Kennedy, Jack

    2016-01-01

    The first government sanctioned delivery of medical supplies by UAS occurred at Wise, Virginia, on July 17, 2015. The "Let's Fly Wisely" event was a demonstration of the humanitarian use of UAS to facilitate delivery of medical supplies to remote or otherwise difficult-to-reach areas. The event was the result of coordinated efforts by a partnership which included the National Aeronautics and Space Administration (NASA) Langley Research Center (LaRC), Virginia Polytechnic Institute, the Mid-Atlantic Aviation Partnership (MAAP), Flirtey Corporation, Lonesome Pine Airport, Remote Area Medical (RAM), Health Wagon, SEESPAN Aerial Interactive, Rx Partnership, and Wise County, Virginia. The historic event occurred during the annual Remote Area Medical clinic at the Wise County Fairgrounds. The medical supplies in small packages were delivered to the Wise County Fairgrounds from the Lonesome Pine Airport by UAS operated by Firtey. A larger supply of medical supplies were delivered to the Lonesome Pine Airport from the Tazewell County Airport by NASA Langley's SR22 UAS Surrogate Research aircraft. The UAS Surrogate aircraft was remotely controlled for most of the flight by a UAS Ground Control Station located at the Lonesome Pine Airport. The medical supplies were delivered from the UAS Surrogate to Flirtey for final delivery by Hex Multi-Rotor UAS in smaller packages and multiple trips to the fairgrounds. A Certificate of Authorization (COA) issued by the Federal Aviation Administration (FAA) designated the site as an authorized UAS test site. The paper will present additional details of the historic delivery of pharmaceuticals by UAS during the "Let's Fly Wisely" event. The paper will also provide details of NASA's SR22 UAS Surrogate Research aircraft. The UAS Surrogate was designed to investigate the procedures, aircraft sensors and other systems that may be required to allow Unmanned Aerial Systems (UAS) to safely operate with manned aircraft in the National Airspace

  1. Research on Improved Control Strategy for STATCOM Based on Virtual Matrix Method

    Directory of Open Access Journals (Sweden)

    Wang Xudong

    2016-01-01

    Full Text Available Fast and accurate detection of reactive current is the precondition for the realization of static synchronous compensator (STATCOM reactive power compensation and harmonic suppression. Aiming at deviation and delay of the traditional reactive current detection algorithm with phase-locked loop (PLL and low-pass filter (LPF of STATCOM, a novel improved reactive current detection algorithm without PLL is proposed, in which the virtual matrix (VM is built to replace the original PLL, and improved current average value filter is used to realize the function of LPF, so as to improve the real-time performance and robustness of reactive current detection. The realization process of VM detection method is derived in this paper, and improved control strategy for STATCOM is designed based on the VM detection method. Simulation analysis of the proposed detection algorithm and control strategy is conducted in Matlab platform so as to verify the correctness and effectiveness of the control strategy. The VM detection has the advantages of simple structure, fast response and easy for digital realization, which provides reference for the improvement of reactive power compensation precision for STATCOM.

  2. Monocyte matrix metalloproteinase production in Type 2 diabetes and controls – a cross sectional study

    Directory of Open Access Journals (Sweden)

    Davies Isabel R

    2003-03-01

    Full Text Available Abstract Background Coronary plaque rupture may result from localised over expression of matrix metalloproteinases (MMPs within the plaque by infiltrating monocyte – macrophages. As MMP expression can be promoted by the modified lipoproteins, oxidative stress and hyperglycaemia that characterises Type 2 diabetes, we hypothesised that peripheral monocytes in these patients, exposed to these factors in vivo, would demonstrate increased MMP production compared to controls. Methods We examined peripheral venous monocyte expression of MMP and tissue inhibitor of metalloproteinase-1 (TIMP-1 in 18 controls and 22 subjects with Type 2 diabetes and no previous cardiovascular complications. Results No significant difference in MMP-1, 3 or 9 or TIMP-1 production was observed between control and diabetes groups. Conclusions Monocyte MMP-1, 3, and 9, and TIMP-1, production are not abnormal in Type 2 diabetes. This data cannot be extrapolated to monocyte – macrophage behaviour in the vessel wall, but it does suggest MMP and TIMP-1 expression prior to monocyte infiltration and transformation are not abnormal in Type 2 diabetes.

  3. Control of Pan-tilt Mechanism Angle using Position Matrix Method

    Directory of Open Access Journals (Sweden)

    Hendri Maja Saputra

    2013-12-01

    Full Text Available Control of a Pan-Tilt Mechanism (PTM angle for the bomb disposal robot Morolipi-V2 using inertial sensor measurement unit, x-IMU, has been done. The PTM has to be able to be actively controlled both manually and automatically in order to correct the orientation of the moving Morolipi-V2 platform. The x-IMU detects the platform orientation and sends the result in order to automatically control the PTM. The orientation is calculated using the quaternion combined with Madwick and Mahony filter methods. The orientation data that consists of angles of roll (α, pitch (β, and yaw (γ from the x-IMU are then being sent to the camera for controlling the PTM motion (pan & tilt angles after calculating the reverse angle using position matrix method. Experiment results using Madwick and Mahony methods show that the x-IMU can be used to find the robot platform orientation. Acceleration data from accelerometer and flux from magnetometer produce noise with standard deviation of 0.015 g and 0.006 G, respectively. Maximum absolute errors caused by Madgwick and Mahony method with respect to Xaxis are 48.45º and 33.91º, respectively. The x-IMU implementation as inertia sensor to control the Pan-Tilt Mechanism shows a good result, which the probability of pan angle tends to be the same with yaw and tilt angle equal to the pitch angle, except a very small angle shift due to the influence of roll angle..

  4. A coordinated control strategy for insulin and glucagon delivery in type 1 diabetes.

    Science.gov (United States)

    Herrero, Pau; Bondia, Jorge; Oliver, Nick; Georgiou, Pantelis

    2017-10-01

    Type 1 diabetes is an autoimmune condition characterised by a pancreatic insulin secretion deficit, resulting in high blood glucose concentrations, which can lead to micro- and macrovascular complications. Type 1 diabetes also leads to impaired glucagon production by the pancreatic α-cells, which acts as a counter-regulatory hormone to insulin. A closed-loop system for automatic insulin and glucagon delivery, also referred to as an artificial pancreas, has the potential to reduce the self-management burden of type 1 diabetes and reduce the risk of hypo- and hyperglycemia. To date, bihormonal closed-loop systems for glucagon and insulin delivery have been based on two independent controllers. However, in physiology, the secretion of insulin and glucagon in the body is closely interconnected by paracrine and endocrine associations. In this work, we present a novel biologically-inspired glucose control strategy that accounts for such coordination. An in silico study using an FDA-accepted type 1 simulator was performed to evaluate the proposed coordinated control strategy compared to its non-coordinated counterpart, as well as an insulin-only version of the controller. The proposed coordinated strategy achieves a reduction of hyperglycemia without increasing hypoglycemia, when compared to its non-coordinated counterpart.

  5. Performance Improvement of Sensorless Vector Control for Matrix Converter Drives Using PQR Transformation

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2005-01-01

    This paper presents a new method to improve sensorless performance of matrix converter drives using PQR power transformation. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled...... drives using a 3 kW matrix converter system without a speed sensor. Experimental results are shown to illustrate the feasibility of the proposed strategy....

  6. Performance improvement of sensorless vector control for matrix converter drives using PQR power theory

    DEFF Research Database (Denmark)

    Lee, Kyo Beum; Blaabjerg, Frede

    2007-01-01

    This paper presents a new method to improve sensorless performance of matrix converter drives using PQR power transformation. The non-linearity of matrix converter drives such as commutation delay, turn-on and turn-off time of switching device, and on-state switching device voltage drop is modelled...... drives using a 3 kW matrix converter system without a speed sensor. Experimental results are shown to illustrate the feasibility of the proposed strategy....

  7. Nanotechnology-based drug delivery systems for control of microbial biofilms: a review

    Science.gov (United States)

    Dos Santos Ramos, Matheus Aparecido; Da Silva, Patrícia Bento; Spósito, Larissa; De Toledo, Luciani Gaspar; Bonifácio, Bruna Vidal; Rodero, Camila Fernanda; Dos Santos, Karen Cristina; Chorilli, Marlus; Bauab, Taís Maria

    2018-01-01

    Since the dawn of civilization, it has been understood that pathogenic microorganisms cause infectious conditions in humans, which at times, may prove fatal. Among the different virulent properties of microorganisms is their ability to form biofilms, which has been directly related to the development of chronic infections with increased disease severity. A problem in the elimination of such complex structures (biofilms) is resistance to the drugs that are currently used in clinical practice, and therefore, it becomes imperative to search for new compounds that have anti-biofilm activity. In this context, nanotechnology provides secure platforms for targeted delivery of drugs to treat numerous microbial infections that are caused by biofilms. Among the many applications of such nanotechnology-based drug delivery systems is their ability to enhance the bioactive potential of therapeutic agents. The present study reports the use of important nanoparticles, such as liposomes, microemulsions, cyclodextrins, solid lipid nanoparticles, polymeric nanoparticles, and metallic nanoparticles, in controlling microbial biofilms by targeted drug delivery. Such utilization of these nanosystems has led to a better understanding of their applications and their role in combating biofilms. PMID:29520143

  8. Facile fabrication of mesoporous ZnO nanospheres for the controlled delivery of captopril

    Science.gov (United States)

    Bakrudeen, Haja Bava; Tsibouklis, John; Reddy, Boreddy S. R.

    2013-03-01

    In the present study, to formulate captopril in a hierarchical porous structure of ZnO nanospheres by means of the soluble-starch-insertion method, state of drug carrier delivery toward oral route and the mode of delivery in suitable medium. Mesoporous ZnO nanospheres were synthesized by simple soluble-starch-insertion method, followed by loading of captopril using ultrasonic force. The materials were characterized by PXRD, SEM, FESEM, TEM, TGA, FT-IR, and BET analyses, and biocompatibility studies. Captopril-loaded porous ZnO nanospheres were evaluated as in vitro drug-release studies and its kinetic models. Crystallite plane arrangement, functional groups, materials morphology, and porosity of porous ZnO nanospheres were confirmed. Larger surface area and distribution in constrained pores on its surface make the nanospheres suitable for high drug loading of captopril. The ZnO nanocrystallites have given porous properties on the spherical surface leads to the drug adsorption. The loading and release studies (in vitro in simulated gastric and intestinal fluids) have shown that both were affected by the mesoporous nanospheres' surface properties of the ZnO materials and its biocompatibility has also been proved. Therefore, the in vitro experiments have indicated the considerable promise of mesoporous ZnO nanospheres, fabricated by the soluble-starch-insertion method acting as a biocompatible carrier for the controlled delivery of captopril in oral route of administration.

  9. Facile fabrication of mesoporous ZnO nanospheres for the controlled delivery of captopril

    Energy Technology Data Exchange (ETDEWEB)

    Bakrudeen, Haja Bava [Central Leather Research Institute (Council of Scientific and Industrial Research), Industrial Chemistry Laboratory (India); Tsibouklis, John [University of Portsmouth, School of Pharmacy and Biomedical Sciences (United Kingdom); Reddy, Boreddy S. R., E-mail: induchem2000@yahoo.com [Central Leather Research Institute (Council of Scientific and Industrial Research), Industrial Chemistry Laboratory (India)

    2013-03-15

    In the present study, to formulate captopril in a hierarchical porous structure of ZnO nanospheres by means of the soluble-starch-insertion method, state of drug carrier delivery toward oral route and the mode of delivery in suitable medium. Mesoporous ZnO nanospheres were synthesized by simple soluble-starch-insertion method, followed by loading of captopril using ultrasonic force. The materials were characterized by PXRD, SEM, FESEM, TEM, TGA, FT-IR, and BET analyses, and biocompatibility studies. Captopril-loaded porous ZnO nanospheres were evaluated as in vitro drug-release studies and its kinetic models. Crystallite plane arrangement, functional groups, materials morphology, and porosity of porous ZnO nanospheres were confirmed. Larger surface area and distribution in constrained pores on its surface make the nanospheres suitable for high drug loading of captopril. The ZnO nanocrystallites have given porous properties on the spherical surface leads to the drug adsorption. The loading and release studies (in vitro in simulated gastric and intestinal fluids) have shown that both were affected by the mesoporous nanospheres' surface properties of the ZnO materials and its biocompatibility has also been proved. Therefore, the in vitro experiments have indicated the considerable promise of mesoporous ZnO nanospheres, fabricated by the soluble-starch-insertion method acting as a biocompatible carrier for the controlled delivery of captopril in oral route of administration.Graphical Abstract.

  10. Nanotechnology-based drug delivery systems for control of microbial biofilms: a review.

    Science.gov (United States)

    Dos Santos Ramos, Matheus Aparecido; Da Silva, Patrícia Bento; Spósito, Larissa; De Toledo, Luciani Gaspar; Bonifácio, Bruna Vidal; Rodero, Camila Fernanda; Dos Santos, Karen Cristina; Chorilli, Marlus; Bauab, Taís Maria

    2018-01-01

    Since the dawn of civilization, it has been understood that pathogenic microorganisms cause infectious conditions in humans, which at times, may prove fatal. Among the different virulent properties of microorganisms is their ability to form biofilms, which has been directly related to the development of chronic infections with increased disease severity. A problem in the elimination of such complex structures (biofilms) is resistance to the drugs that are currently used in clinical practice, and therefore, it becomes imperative to search for new compounds that have anti-biofilm activity. In this context, nanotechnology provides secure platforms for targeted delivery of drugs to treat numerous microbial infections that are caused by biofilms. Among the many applications of such nanotechnology-based drug delivery systems is their ability to enhance the bioactive potential of therapeutic agents. The present study reports the use of important nanoparticles, such as liposomes, microemulsions, cyclodextrins, solid lipid nanoparticles, polymeric nanoparticles, and metallic nanoparticles, in controlling microbial biofilms by targeted drug delivery. Such utilization of these nanosystems has led to a better understanding of their applications and their role in combating biofilms.

  11. A Computational Procedure for Assessing the Dynamic Performance of Diffusion-Controlled Transdermal Delivery Devices

    Directory of Open Access Journals (Sweden)

    Laurent Simon

    2011-08-01

    Full Text Available Abstract: The dynamic performances of two different controlled-release systems were analyzed. In a reservoir-type drug-delivery patch, the transdermal flux is influenced by the properties of the membrane. A constant thermodynamic drug activity is preserved in the donor compartment. Monolithic matrices are among the most inexpensive systems used to direct drug delivery. In these structures, the active pharmaceutical ingredients are encapsulated within a polymeric material. Despite the popularity of these two devices, to tailor the properties of the polymer and additives to specific transient behaviors can be challenging and time-consuming. The heuristic approaches often considered to select the vehicle formulation provide limited insight into key permeation mechanisms making it difficult to predict the device performance. In this contribution, a method to calculate the flux response time in a system consisting of a reservoir and a polymeric membrane was proposed and confirmed. Nearly 8.60 h passed before the metoprolol delivery rate reached ninety-eight percent of its final value. An expression was derived for the time it took to transport the active pharmaceutical ingredient out of the polymer. Ninety-eight percent of alpha-tocopherol acetate was released in 461.4 h following application to the skin. The effective time constant can be computed to help develop optimum design strategies.

  12. A randomized placebo-controlled trial of preoperative tranexamic acid among women undergoing elective cesarean delivery.

    Science.gov (United States)

    Maged, Ahmed M; Helal, Omneya M; Elsherbini, Moutaz M; Eid, Marwa M; Elkomy, Rasha O; Dahab, Sherif; Elsissy, Maha H

    2015-12-01

    To study the efficacy and safety of preoperative intravenous tranexamic acid to reduce blood loss during and after elective lower-segment cesarean delivery. A single-blind, randomized placebo-controlled study was undertaken of women undergoing elective lower-segment cesarean delivery of a full-term singleton pregnancy at a center in Cairo, Egypt, between November 2013 and November 2014. Patients were randomly assigned (1:1) using computer-generated random numbers to receive either 1g tranexamic acid or 5% glucose 15 minutes before surgery. Preoperative and postoperative complete blood count, hematocrit values, and maternal weight were used to calculate the estimated blood loss (EBL) during cesarean, which was the primary outcome. Analyses included women who received their assigned treatment, whose surgery was 90 minutes or less, and who completed follow-up. Analyses included 100 women in each group. Mean EBL was significantly higher in the placebo group (700.3 ± 143.9 mL) than in the tranexamic acid group (459.4 ±7 5.4 mL; Pcesarean delivery. Australian New Zealand Clinical Trials Registry:ACTRN12615000312549. Copyright © 2015 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  13. [Research progress on a nanodrug delivery system for prevention and control of dental caries and periodontal diseases].

    Science.gov (United States)

    Yaling, Jiang; Mingye, Feng; Lei, Cheng

    2017-02-01

    Dental caries and periodontal diseases are common chronic infectious diseases that cause serious damage to oral health. Bacteria is the primary factor leading to such conditions. As a dental plaque control method, chemotherapeutic agents face serious challenges in dental care because of the specific physiological and anatomical characteristics of the oral cavity. Nanodrug delivery system is a series of new drug delivery systems at nanoscale, and it can target cells, promote sustainedrelease effects, and enhance biodegradation. This review focuses on research progress on nanodrug delivery systems for prevention and control of dental caries and periodontal diseases.

  14. Composite Scaffold of Poly(Vinyl Alcohol) and Interfacial Polyelectrolyte Complexation Fibers for Controlled Biomolecule Delivery

    Science.gov (United States)

    Cutiongco, Marie Francene A.; Choo, Royden K. T.; Shen, Nathaniel J. X.; Chua, Bryan M. X.; Sju, Ervi; Choo, Amanda W. L.; Le Visage, Catherine; Yim, Evelyn K. F.

    2015-01-01

    Controlled delivery of hydrophilic proteins is an important therapeutic strategy. However, widely used methods for protein delivery suffer from low incorporation efficiency and loss of bioactivity. The versatile interfacial polyelectrolyte complexation (IPC) fibers have the capacity for precise spatiotemporal release and protection of protein, growth factor, and cell bioactivity. Yet its weak mechanical properties limit its application and translation into a viable clinical solution. To overcome this limitation, IPC fibers can be incorporated into polymeric scaffolds such as the biocompatible poly(vinyl alcohol) hydrogel (PVA). Therefore, we explored the use of a composite scaffold of PVA and IPC fibers for controlled biomolecule release. We first observed that the permeability of biomolecules through PVA films were dependent on molecular weight. Next, IPC fibers were incorporated in between layers of PVA to produce PVA–IPC composite scaffolds with different IPC fiber orientation. The composite scaffold demonstrated excellent mechanical properties and efficient biomolecule incorporation. The rate of biomolecule release from PVA–IPC composite grafts exhibited dependence on molecular weight, with lysozyme showing near-linear release for 1 month. Angiogenic factors were also incorporated into the PVA–IPC grafts, as a potential biomedical application of the composite graft. While vascular endothelial growth factor only showed a maximum cumulative release of 3%, the smaller PEGylated-QK peptide showed maximum release of 33%. Notably, the released angiogenic biomolecules induced endothelial cell activity thus indicating retention of bioactivity. We also observed lack of significant macrophage response against PVA–IPC grafts in a rabbit model. Showing permeability, mechanical strength, precise temporal growth factor release, and bioinertness, PVA–IPC fibers composite scaffolds are excellent scaffolds for controlled biomolecule delivery in soft tissue

  15. Composite scaffold of poly(vinyl alcohol and interfacial polyelectrolyte complexation fibers for controlled biomolecule delivery

    Directory of Open Access Journals (Sweden)

    Marie Francene Arnobit Cutiongco

    2015-02-01

    Full Text Available Controlled delivery of hydrophilic proteins is an important therapeutic strategy. However, widely used methods for protein delivery suffer from low incorporation efficiency and loss of bioactivity. The versatile interfacial polyelectrolyte complexation (IPC fibers have the capacity for precise spatiotemporal release and protection of protein, growth factor and cell bioactivity. Yet its weak mechanical properties limit its application and translation into a viable clinical solution. To overcome this limitation, IPC fibers can be incorporated into polymeric scaffolds such as the biocompatible poly(vinyl alcohol hydrogel (PVA. Therefore, we explored the use of a composite scaffold of PVA and IPC fibers for controlled biomolecule release. We first observed that the permeability of biomolecules through PVA films were dependent on molecular weight, with lysozyme showing near-linear release for 1 month. Next, IPC fibers were incorporated in between layers of PVA to produce PVA-IPC composite scaffolds with different IPC fiber orientation. The composite scaffold demonstrated excellent mechanical properties and efficient biomolecule incorporation. The rate of biomolecule release from PVA-IPC composite grafts exhibited dependence on molecular weight. Angiogenic factors were also incorporated into the PVA-IPC grafts, as a potential biomedical application of the composite graft. While vascular endothelial growth factor only showed a maximum cumulative release of 3%, the smaller PEGylated-QK peptide showed maximum release of 33%. Notably, the released angiogenic biomolecules induced endothelial cell metabolic activity thus indicating retention of bioactivity. We also observed lack of significant macrophage response against PVA-IPC grafts in a rabbit model. Showing permeability, mechanical strength, precise temporal growth factor release and bioinertness, PVA-IPC fibers composite scaffolds are excellent scaffolds for controlled biomolecule delivery in soft

  16. The use of quality control performance charts to analyze cesarean delivery rates nationally.

    LENUS (Irish Health Repository)

    Turner, Michael J

    2012-02-01

    OBJECTIVE: To examine the use of quality control performance charts to analyze cesarean rates nationally. METHODS: Information on cesarean rates was obtained for all 19 Irish maternity hospitals receiving state funding in 2009. All women who underwent cesarean delivery of a live or stillborn infant weighing 500 g or more between January 1 and December 31 were included. Deliveries were classified as elective or emergency. Individual hospitals were not identified in the analysis. RESULTS: The mean rates per hospital of elective and emergency cesarean were 12.9+\\/-2.6% (n=9337) and 13.8+\\/-3.0% (n=9989), respectively-giving an overall mean rate of 26.7+\\/-4.2% (n=19326) per hospital. Cesarean rates were normally distributed. Using a quality control performance chart with a cutoff 2 standard deviations from the mean, 1 hospital was above the normal range for both total and elective cesareans, indicating that its pre-labor obstetric practices warrant clinical review. Another hospital had a mean emergency cesarean rate above the normal range, indicating that its labor ward practices warrant review. CONCLUSION: Quality control performance charts can be used to analyze cesarean rates nationally and, thus, to identify hospitals at which obstetric practices should be reviewed.

  17. Liquid crystalline systems containing Vitamin E TPGS for the controlled transdermal nicotine delivery

    Directory of Open Access Journals (Sweden)

    Lívia Neves Borgheti-Cardoso

    Full Text Available ABSTRACT Transdermal nicotine patches have been used in smoking cessation therapy, suggested for the treatment of skin disorders with eosinophilic infiltration and have been found to improve attention performance in patients with Alzheimer's disease and age-associated memory impairment. However, skin irritation with extended patch use is still a problem. The aim of this work was to develop a simple to prepare liquid crystalline system containing vitamin E TPGS that would be able to control nicotine delivery and reduce irritation and sensitization problems. The liquid crystalline phases were macroscopically characterized by visual analysis and examined microscopically under a polarized light microscope. Topical and transdermal delivery of nicotine were investigated in vitro using porcine ear skin mounted on a Franz diffusion cell. Nicotine skin permeation from the developed cubic phase followed zero-order kinetics (r = 0.993 and was significantly enhanced after 12 h when compared to the control formulation (nicotine solution (p < 0.05 (138.86 ± 20.44 and 64.91 ± 4.06 μg/cm2, respectively. Cubic phase was also able to target viable skin layers in comparison to control solution (8.18 ± 1.89 and 2.63 ± 2.51 μg/cm2, respectively. Further studies to evaluate skin sensitization and irritation are now necessary.

  18. Congestion control in wireless links based on selective delivery of erroneous packets

    DEFF Research Database (Denmark)

    Korhonen, Jari; Perkis, Andrew; Reiter, Ulrich

    2011-01-01

    Traditionally, congestion control in packet networks is performed by reducing the transmission rate when congestion is detected, in order to cut down the traffic that overwhelms the capacity of the network. However, if the bottleneck is a wireless link, congestion is often cumulated because...... of bit errors appearing in the packet payload. In this paper, we study a congestion control mechanism for streaming applications that combines traditional congestion control with selective link layer partial checksumming allowing bit errors in the less sensitive parts of data. We have compared...... of retransmissions derived from bit errors. In this case, it might be beneficial to allow delivery of partly corrupted packets up to the application layer instead of reducing the transmission rate. This would decrease the number of retransmissions in the link layer and therefore relieve congestion, but at the cost...

  19. Novel Hydrogel-Advanced Modified Clay Nanocomposites as Possible Vehicles for Drug Delivery and Controlled Release

    Directory of Open Access Journals (Sweden)

    Raluca Ianchis

    2017-12-01

    Full Text Available Present study refers to the synthesis of new advanced materials based on poly(methacrylic acid (PMAA with previously reported own advanced modified clays by edge covalent bonding. This will create the premises to obtain nanocomposite hydrogels with combined hydrophilic-hydrophobic behavior absolutely necessary for co-delivery of polar/nonpolar substances. For the synthesis, N,N’-methylenebisacrylamide was used as cross-linker and ammonium persulphate as initiator. As a consequence of the inclusion of clay into the polymer matrix and the intercalation of PMAA between the layers as well as the presence of hydrophobic interactions occurred between partners, the final hydrogel nanocomposites possessed greater swelling degrees, slower de-swelling process and enhanced mechanical properties depending on the clay type in comparison with pure hydrogel. In vitro MTS ([3-(4,5-dimethylthiazol-2-yl-5-(3-carboxymethoxyphenyl-2-(4-sulfophenyl-2H-tetrazolium, inner salt] colorimetric assay showed that direct exposure with PMMA-clay-based constructs did not affect cell viability and proliferation in time (24 and 48 h on either normal or adenocarcinoma cell lines.

  20. Novel Hydrogel-Advanced Modified Clay Nanocomposites as Possible Vehicles for Drug Delivery and Controlled Release.

    Science.gov (United States)

    Ianchis, Raluca; Ninciuleanu, Claudia M; Gifu, Ioana C; Alexandrescu, Elvira; Somoghi, Raluca; Gabor, Augusta R; Preda, Silviu; Nistor, Cristina L; Nitu, Sabina; Petcu, Cristian; Icriverzi, Madalina; Florian, Paula E; Roseanu, Anca M

    2017-12-13

    Present study refers to the synthesis of new advanced materials based on poly(methacrylic acid) (PMAA) with previously reported own advanced modified clays by edge covalent bonding. This will create the premises to obtain nanocomposite hydrogels with combined hydrophilic-hydrophobic behavior absolutely necessary for co-delivery of polar/nonpolar substances. For the synthesis, N , N '-methylenebisacrylamide was used as cross-linker and ammonium persulphate as initiator. As a consequence of the inclusion of clay into the polymer matrix and the intercalation of PMAA between the layers as well as the presence of hydrophobic interactions occurred between partners, the final hydrogel nanocomposites possessed greater swelling degrees, slower de-swelling process and enhanced mechanical properties depending on the clay type in comparison with pure hydrogel. In vitro MTS ([3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H -tetrazolium, inner salt]) colorimetric assay showed that direct exposure with PMMA-clay-based constructs did not affect cell viability and proliferation in time (24 and 48 h) on either normal or adenocarcinoma cell lines.

  1. Severe postpartum haemorrhage after vaginal delivery: a statistical process control chart to report seven years of continuous quality improvement.

    Science.gov (United States)

    Dupont, Corinne; Occelli, Pauline; Deneux-Tharaux, Catherine; Touzet, Sandrine; Duclos, Antoine; Bouvier-Colle, Marie-Hélène; Rudigoz, René-Charles; Huissoud, Cyril

    2014-07-01

    Severe postpartum haemorrhage after vaginal delivery: a statistical process control chart to report seven years of continuous quality improvement To use statistical process control charts to describe trends in the prevalence of severe postpartum haemorrhage after vaginal delivery. This assessment was performed 7 years after we initiated a continuous quality improvement programme that began with regular criteria-based audits Observational descriptive study, in a French maternity unit in the Rhône-Alpes region. Quarterly clinical audit meetings to analyse all cases of severe postpartum haemorrhage after vaginal delivery and provide feedback on quality of care with statistical process control tools. The primary outcomes were the prevalence of severe PPH after vaginal delivery and its quarterly monitoring with a control chart. The secondary outcomes included the global quality of care for women with severe postpartum haemorrhage, including the performance rate of each recommended procedure. Differences in these variables between 2005 and 2012 were tested. From 2005 to 2012, the prevalence of severe postpartum haemorrhage declined significantly, from 1.2% to 0.6% of vaginal deliveries (pcontinuous quality improvement efforts began seven years ago and used, among other tools, statistical process control charts. During this period, the prevalence of severe postpartum haemorrhage after vaginal delivery has been reduced by 50%. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  2. Characterization of a polyurethane-based controlled release system for local delivery of chlorhexidine diacetate.

    Science.gov (United States)

    Huynh, Truc Thanh Ngoc; Padois, Karine; Sonvico, Fabio; Rossi, Alessandra; Zani, Franca; Pirot, Fabrice; Doury, Jacques; Falson, Françoise

    2010-02-01

    Conventional formulations of chlorhexidine usually provide short-term efficiency, requiring repeated applications to maintain antibacterial activity. Therefore, appropriate release system of chlorhexidine controlling local drug delivery would reduce the number of applications and enhance patient compliance. The aim of this study was to develop a controlled release system based on medical polyurethane for the local delivery of chlorhexidine diacetate (CDA). CDA-loaded polyurethane films (CDA-Films) and CDA-loaded polyurethane sandwiches (CDA-Sandwiches) were obtained by casting and solvent evaporation. The physico-chemical aspects of CDA-loaded polyurethane systems were investigated, and the crystalline state of CDA in the polymeric system was highlighted. CDA-Films exhibited appropriate mechanical properties for further applications. Drug release was measured in two different media: (i) distilled water and (ii) physiological saline solution to mimic in vivo conditions. Drug release studies were performed up to 11days on CDA-Films and 29days for CDA-Sandwiches. Release of CDA depended on drug loading and the structure of the system. In particular, release of CDA from the sandwich system followed zero-order kinetic. The release rate was significantly lower in physiological solution. Antibacterial studies were carried out on CDA-Films against Staphylococcus aureus and Staphylococcus epidermidis showing 35days persisting antibacterial activity. In conclusion, the polyurethane-based system developed in this study is potentially useful as a local delivery system for CDA and could be used not only in surgery but also in dental and clinical applications. Copyright (c) 2009 Elsevier B.V. All rights reserved.

  3. Microprocessor in controlled transdermal drug delivery of anti-cancer drugs.

    Science.gov (United States)

    Chandrashekar, N S; Shobha Rani, R H

    2009-12-01

    Microprocessor controlled transdermal delivery of anticancer drugs 5-Fluorouracil (5-FU) and 6-Mercaptopurine (6-MP) was developed and in vitro evaluation was done. Drugs were loaded based on the pharmacokinetics parameters. In vitro diffusion studies were carried at different current density (0.0, 0.1, 0.22, 0.50 mA/cm2). The patches were evaluated for the drug content, thickness, weight, folding endurance, flatness, thumb tack test and adhesive properties all were well with in the specification of transdermal patches with elegant and transparent in appearance. In vitro permeation studies through human cadaver skin showed, passive delivery (0.0 mA/cm2) of 6-MP was low. As the current density was progressively increased, the flux also increased. the flux also increased with 0.1 mA/cm2 for 15-20 min, but it was less than desired flux, 0.2 mA/cm2 for 30 min showed better flux than 0.1 mA/cm2 current, but lag time was more than 4 h, 0.5 mA/cm2 current for more than 1 h, flux was >159 microg/cm2 h which was desired flux for 6-MP. 5-FU flux reached the minimum effective concentration (MEC) of 54 microg/cm2 h with 0.5 mA/cm2 current for 30-45 min, drug concentration were within the therapeutic window in post-current phase. We concluded from Ohm's Law that as the resistance decreases, current increases. Skin resistance decrease with increase in time and current, increase in the drug permeation. Interestingly, for all investigated current densities, as soon as the current was switched off, 5-FU and 6-MP flux decreased fairly, but the controlled drug delivery can be achieved by switching the current for required period of time.

  4. Development of PEGylated PLGA nanoparticle for controlled and sustained drug delivery in cystic fibrosis

    Directory of Open Access Journals (Sweden)

    Mazur Steven

    2010-09-01

    Full Text Available Abstract Background The mutation in the cystic fibrosis transmembrane conductance regulator (CFTR gene results in CF. The most common mutation, ΔF508-CFTR, is a temperature-sensitive, trafficking mutant with reduced chloride transport and exaggerated immune response. The ΔF508-CFTR is misfolded, ubiquitinated, and prematurely degraded by proteasome mediated- degradation. We recently demonstrated that selective inhibition of proteasomal pathway by the FDA approved drug PS-341 (pyrazylcarbonyl-Phe-Leuboronate, a.k.a. Velcade or bortezomib ameliorates the inflammatory pathophysiology of CF cells. This proteasomal drug is an extremely potent, stable, reversible and selective inhibitor of chymotryptic threonine protease-activity. The apprehension in considering the proteasome as a therapeutic target is that proteasome inhibitors may affect proteostasis and consecutive processes. The affect on multiple processes can be mitigated by nanoparticle mediated PS-341 lung-delivery resulting in favorable outcome observed in this study. Results To overcome this challenge, we developed a nano-based approach that uses drug loaded biodegradable nanoparticle (PLGA-PEGPS-341 to provide controlled and sustained drug delivery. The in vitro release kinetics of drug from nanoparticle was quantified by proteasomal activity assay from days 1-7 that showed slow drug release from day 2-7 with maximum inhibition at day 7. For in vivo release kinetics and biodistribution, these drug-loaded nanoparticles were fluorescently labeled, and administered to C57BL6 mice by intranasal route. Whole-body optical imaging of the treated live animals demonstrates efficient delivery of particles to murine lungs, 24 hrs post treatment, followed by biodegradation and release over time, day 1-11. The efficacy of drug release in CF mice (Cftr-/- lungs was determined by quantifying the changes in proteasomal activity (~2 fold decrease and ability to rescue the Pseudomonas aeruginosa LPS (Pa

  5. Battery available power prediction of hybrid electric vehicle based on improved Dynamic Matrix Control algorithms

    Science.gov (United States)

    Wang, Limei; Cheng, Yong; Zou, Ju

    2014-09-01

    The core technology to any hybrid engine vehicle (HEV) is the design of energy management strategy (EMS). To develop a reasonable EMS, it is necessary to monitor the state of capacity, state of health and instantaneous available power of battery packs. A new method that linearizes RC equivalent circuit model and predicts battery available power according to original Dynamic Matrix Control algorithm is proposed. To verify the validity of the new algorithm, a bench test with lithium-ion battery cell and a HEV test with lithium-ion battery packs are carried out. The bench test results indicate that a single RC block equivalent circuit model could be used to describe the dynamic and the steady state characteristics of a battery under testing conditions. However, lacking of long time constant of RC modules, there is a sample deviation in the open-circuit voltage identified and that measured. The HEV testing results show that the battery voltage predicted is in good agreement with that measured, the maximum difference is within 3.7%. Fixing the time constant to a numeric value, satisfactory results can still be achieved. After setting a battery discharge cut-off voltage, the instantaneous available power of the battery can be predicted.

  6. Poly lactic acid based injectable delivery systems for controlled release of a model protein, lysozyme.

    Science.gov (United States)

    Al-Tahami, Khaled; Meyer, Amanda; Singh, Jagdish

    2006-02-01

    The objective of this study was to evaluate the critical formulation parameters (i.e., polymer concentration, polymer molecular weight, and solvent nature) affecting the controlled delivery of a model protein, lysozyme, from injectable polymeric implants. The conformational stability and biological activity of the released lysozyme were also investigated. Three formulations containing 10%, 20%, and 30% (w/v) poly lactic acid (PLA) in triacetin were investigated. It was found that increasing polymer concentration in the formulations led to a lower burst effect and a slower release rate. Formulation with a high molecular weight polymer showed a greater burst effect as compared to those containing low molecular weight. Conformational stability and biological activity of released samples were studied by differential scanning calorimeter and enzyme activity assay, respectively. The released samples had significantly (P solution kept at same conditions). Increasing polymer concentration increased both the conformational stability and the biological activity of released lysozyme. In conclusion, phase sensitive polymer-based delivery systems were able to deliver a model protein, lysozyme, in a conformationally stable and biologically active form at a controlled rate over an extended period.

  7. Spatial regulation of controlled bioactive factor delivery for bone tissue engineering

    Science.gov (United States)

    Samorezov, Julia E.; Alsberg, Eben

    2015-01-01

    Limitations of current treatment options for critical size bone defects create a significant clinical need for tissue engineered bone strategies. This review describes how control over the spatiotemporal delivery of growth factors, nucleic acids, and drugs and small molecules may aid in recapitulating signals present in bone development and healing, regenerating interfaces of bone with other connective tissues, and enhancing vascularization of tissue engineered bone. State-of-the-art technologies used to create spatially controlled patterns of bioactive factors on the surfaces of materials, to build up 3D materials with patterns of signal presentation within their bulk, and to pattern bioactive factor delivery after scaffold fabrication are presented, highlighting their applications in bone tissue engineering. As these techniques improve in areas such as spatial resolution and speed of patterning, they will continue to grow in value as model systems for understanding cell responses to spatially regulated bioactive factor signal presentation in vitro, and as strategies to investigate the capacity of the defined spatial arrangement of these signals to drive bone regeneration in vivo. PMID:25445719

  8. Cell adhesion control by ion implantation into extra-cellular matrix

    International Nuclear Information System (INIS)

    Suzuki, Yoshiaki; Kusakabe, Masahiro; Kaibara, Makoto; Iwaki, Masaya; Sasabe, Hiroyuki; Nishisaka, Tsuyoshi

    1994-01-01

    Cell adhesion control of polymer surfaces by ion implantation into polymers and extra-cellular matrix has been studied by means of in vitro adhesion measurements of the carcinoma of the cervix (HeLa cell). The specimens used were polystyrene (PS), oxygen plasma treated polystyrene (PS-O), extra-cellular matrix (Collagen: Type I) coated polystyrene (PS-C), and gelatin coated polystyrene (PS-G). Ne + , Na + , and Ar + implantations were performed with a fluence of 1x10 15 ions/cm 2 at energies of 50, 100 and 150 keV. The chemical and physical structures of ion implanted specimens have been investigated by Fourier transform infrared spectroscopy (FT-IR-ATR), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. Ion implanted PS demonstrated a dramatic improvement of adhesion of HeLa cell. HeLa cell adhered only to ion implanted circular domains of a diameter about 0.1 mm on PS. By contrast, ion implanted PS-C, PS-G and PS-O domains inhibited the cell adhesion. These phenomena were observed on Ne + , Na + , and Ar + implanted specimens at energies of 50, 100, and 150 keV. Ion implantation broke the original chemical bonds to form new radicals such as =C=O, condensed rings, C-C, C-O and OH radical. Ion implanted PS had a large amount of new radicals compared with that of PS-C, PS-G and PS-O. Ion implantation broke NH and NH 3 bonds originating from amino acid in PS-C and PS-G. OH and =C=O caused by oxygen treatment in PS-O were also destroyed by ion implantation. It is concluded that cell adhesion to ion implanted PS was caused by carbon structure and new radicals induced by ion implantation. The inhibition of HeLa cell adhesion on PS-C, PS-G and PS-O was caused by the destruction of cell adhesion properties of amino acid, OH and =C=O by radiation effects. ((orig.))

  9. Modulation of Tenoxicam release from hydrophilic matrix: modulator membrane versus rate-controlling membrane.

    Science.gov (United States)

    El-Nabarawi, Mohamed Ahmed

    2005-09-01

    This paper describes the preparation of two layered device comprising of tenoxicam containing layer and a drug free membrane layer based on Geomatrix Technology. Our device based on bilaminated films which produced by a casting/solvent evaporation technique. The drug-hydroxypropyl methylcellulose (HPMC) layer was covered by drug free membrane layer composed of a mixture of different ratios of HPMC and ethyl cellulose (EC). The prepared devices were evaluated for thickness, weight, drug content uniformity, water absorption capacity and in-vitro drug release. The films were also evaluated for appearance, smoothness and transparency. The influence of drug free membrane layer composition and thickness on the drug release pattern was studied on 12 devices (D1 to D12). The results indicate that, the release of drug from HPMC matrixes without the drug free membrane layer was fast and follows diffusion controlled mechanism. The release of drug from the devices D1, D4, D9 and D12 follow the same mechanism, while the release of drug from other devices become linear with time (zero order) and extended for long time especially when thickness and the ratio of EC was increased in the drug free membrane layer. From this study it is concluded that, changing the geometry of drug layer by addition of drug free membrane layer and changing its composition and thickness plays an important role in determining whether the drug free membrane layer is rate-controlling or modulator membrane. Hence it can facilitate the development of different pharmaceutical products with different release pattern.

  10. Reduced Order Extended Luenberger Observer Based Sensorless Vector Control Fed by Matrix Converter with Non-linearity Modeling

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2004-01-01

    This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with non-linearity compensation. The nonlinear voltage distortion that is caused by commutation delay and on-state voltage drop in switching device is corrected by a new...... matrix converter model. Regulated Order Extended Luenberger Observer (ROELO) is employed to bring better response in the whole speed operation range and a method to select the observer gain is presented. Experimental results are shown to illustrate the performance of the proposed system...

  11. Incentive systems for food quality control with repeated deliveries: Salmonella control in pork production

    NARCIS (Netherlands)

    King, R.P.; Backus, G.B.C.; Gaag, van der M.A.

    2007-01-01

    This paper presents a dynamic principal-agent analysis of incentive systems for Salmonella control. The European Union will require Salmonella testing from 2008. On the basis of the producer's performance history in controlling Salmonella, the incentive systems analysed determine quality premiums to

  12. Use of hydrophilic and hydrophobic polymers for the development of controlled release tizanidine matrix tablets

    Directory of Open Access Journals (Sweden)

    Tariq Ali

    2014-12-01

    Full Text Available The aim of the present study was to develop tizanidine controlled release matrix. Formulations were designed using central composite method with the help of design expert version 7.0 software. Avicel pH 101 in the range of 14-50% was used as a filler, while HPMC K4M and K100M in the range of 25-55%, Ethylcellulose 10 ST and 10FP in the range of 15 - 45% and Kollidon SR in the range of 25-60% were used as controlled release agents in designing different formulations. Various physical parameters including powder flow for blends and weight variation, thickness, hardness, friability, disintegration time and in-vitro release were tested for tablets. Assay of tablets were also performed as specified in USP 35 NF 32. Physical parameters of both powder blend and compressed tablets such as compressibility index, angle of repose, weight variation, thickness, hardness, friability, disintegration time and assay were evaluated and found to be satisfactory for formulations K4M2, K4M3, K4M9, K100M2, K100M3, K100M9, E10FP2, E10FP9, KSR2, KSR3 & KSR9. In vitro dissolution study was conducted in 900 ml of 0.1N HCl, phosphate buffer pH 4.5 and 6.8 medium using USP Apparatus II. In vitro release profiles indicated that formulations prepared with Ethocel 10 standard were unable to control the release of drug while formulations K4M2, K100M9, E10FP2 & KSR2 having polymer content ranging from 40-55% showed a controlled drug release pattern in the above mentioned medium. Zero-order drug release kinetics was observed for formulations K4M2, K100M9, E10FP2 & KSR2. Similarity test (f2 results for K4M2, E10FP2 & KSR2 were found to be comparable with reference formulation K100M9. Response Surface plots were also prepared for evaluating the effect of independent variable on the responses. Stability study was performed as per ICH guidelines and the calculated shelf life was 24-30 months for formulation K4M2, K100M9 and E10FP2.

  13. Glutathione-responsive core cross-linked micelles for controlled cabazitaxel delivery

    Science.gov (United States)

    Han, Xiaoxiong; Gong, Feirong; Sun, Jing; Li, Yueqi; Liu, XiaoFei; Chen, Dan; Liu, Jianwen; Shen, Yaling

    2018-02-01

    Stimulus-responsive polymeric micelles (PMs) have recently received attention due to the controlled delivery of drug or gene for application in cancer diagnosis and treatment. In this work, novel glutathione-responsive PMs were prepared to encapsulate hydrophobic antineoplastic drug, cabazitaxel (CTX), to improve its solubility and toxicity. These CTX-loaded micelles core cross-linked by disulfide bonds (DCL-CTX micelles) were prepared by a novel copolymer, lipoic acid grafted mPEG-PLA. These micelles had regular spherical shape, homogeneous diameter of 18.97 ± 0.23 nm, and a narrow size distribution. The DCL-CTX micelles showed high encapsulation efficiency of 98.65 ± 1.77%, and the aqueous solubility of CTX was improved by a factor of 1:1200. In vitro release investigation showed that DCL-CTX micelles were stable in the medium without glutathione (GSH), whereas the micelles had burst CTX release in the medium with 10 mM GSH. Cell uptake results implied that DCL-CTX micelles were internalized into MCF-7 cells through clathrin-mediated endocytosis and released cargo more effectively than Jevtana (commercially available CTX) owing to GSH-stimulated degradation. In MTT assay against MCF-7 cells, these micelles inhibited tumor cell proliferation more effectively than Jevtana due to their GSH-responsive CTX release. All results revealed the potency of GSH-responsive DCL-CTX micelles for stable delivery in blood circulation and for intracellular GSH-trigged release of CTX. Therefore, DCL-CTX micelles show potential as safe and effective CTX delivery carriers and as a cancer chemotherapy formulation.

  14. Preoperative cesarean delivery intravenous acetaminophen treatment for postoperative pain control: a randomized double-blinded placebo control trial.

    Science.gov (United States)

    Towers, Craig V; Shelton, Sarah; van Nes, Jaclyn; Gregory, Emily; Liske, Emily; Smalley, Arion; Mobley, Edward; Faircloth, Barbara; Fortner, Kim B

    2018-03-01

    The United States currently has an opioid use disorder epidemic and research evaluating ways to minimize the use of opioids postsurgery are needed. One of these options is intravenous acetaminophen. If the use of preoperative intravenous acetaminophen was found to be effective for cesarean delivery, this would be beneficial for both the mother and breast-feeding neonate. The primary study objective was to see if maternal opioid use was significantly less in the postoperative period for the study group that received 1 g of intravenous acetaminophen preoperatively compared with a control group that received placebo. The secondary objectives were to evaluate maternal length of stay and pain scores postoperatively, and assess the acetaminophen level in cord blood at delivery. This study was a prospective double-blinded randomized placebo-controlled trial. All pregnant patients who entered labor and delivery for a scheduled cesarean from November 2015 through April 2017 were eligible. Once consented, the medication was supplied by the pharmacy department, which performed the blinded randomization. Both the study drug of 1000 mg (1 g) of acetaminophen and placebo of normal saline were distributed as unmarked 100-mL bags administered over 15 minutes just prior to incision. No study personnel from the obstetric or anesthesia departments had any access to the randomization. Based on a power analysis using the published surgical data results, the goal was to obtain a minimum of 100 patients (50 patients in each arm). Primary data collection included demographics, number of opioid doses and morphine milligram equivalents administered to the patient postoperatively, length of stay postdelivery, pain scores, and newborn cord blood acetaminophen levels. Exclusions were maternal acetaminophen allergy, receipt of acetaminophen in the prior 24 hours, opioid use disorder, and hepatitis/liver impairment. Statistics involved χ 2 , Fisher exact, and the Student t test where

  15. Inserting the tap values of the tap changer transformers into the Jacobian matrix as control variables

    Directory of Open Access Journals (Sweden)

    Faruk Yalçın

    2013-06-01

    Full Text Available Series and shunt admittance values of under load tap changer transformers are changed according to tap changing. As this situation changes the structure of bus admittance matrix, it causes the need of rebuilding the bus admittance matrix at each tap changing case in power flow studies. In this paper, a new approach that includes the tap changing effects into the Jacobian matrix. By this approach, the need of rebuilding the bus admittance matrix at each tap changing case during power flow study is prevented. So, fast convergence is achieved for the power flow algorithm. Although there are similar studies for this aim in the literature, apart from these studies, including the tap changing effects to the Jacobian matrix when more than one under load tap changer transformers are connected to the same bus with different connection combinations is provided by the proposed approach. For this aim, new power equations and new Jacobian matrix component calculation equations are obtained. The proposed approach is tested on IEEE 57-bus test system and its accuracy is proved.

  16. Effect of ca2+ to salicylic acid release in pectin based controlled drug delivery system

    Science.gov (United States)

    Kistriyani, L.; Wirawan, S. K.; Sediawan, W. B.

    2016-01-01

    Wastes from orange peel are potentially be utilized to produce pectin, which are currently an import commodity. Pectin can be used in making edible film. Edible films are potentially used as a drug delivery system membrane after a tooth extraction. Drug which is used in the drug delivery system is salicylic acid. It is an antiseptic. In order to control the drug release rate, crosslinking process is added in the manufacturing of membrane with CaCl2.2H2O as crosslinker. Pectin was diluted in water and mixed with a plasticizer and CaCl2.2H2O solution at 66°C to make edible film. Then the mixture was dried in an oven at 50 °C. After edible film was formed, it was coated using plasticizer and CaCl2.2H2O solution with various concentration 0, 0.015, 0.03 and 0.05g/mL. This study showed that the more concentration of crosslinker added, the slower release of salicylic acid would be. This was indicated by the value of diffusivites were getting smaller respectively. The addition of crosslinker also caused smaller gels swelling value,which made the membrane is mechanically stronger

  17. Polypyrrole Film as a Drug Delivery System for the Controlled Release of Risperidone

    Science.gov (United States)

    Svirskis, Darren; Travas-Sejdic, Jadranka; Rodgers, Anthony; Garg, Sanjay

    2009-07-01

    Conducting polymers are finding applications in medicine including drug delivery systems, biosensors and templates for the regeneration of nervous pathways. We aim to develop a novel system where the drug release rate can be controlled by electrical stimulation. Polypyrrole (PPY) is being used as a drug delivery system due to its inherent electrical conductivity, ease of preparation and apparent biocompatibility. Risperidone is an atypical antipsychotic drug used in the treatment of psychosis and related disorders, including schizophrenia. PPY was synthesised using p-toluene sulfonic acid as a primary dopant, in the presence of risperidone. A validated high performance liquid chromatography (HPLC) analytical method was used to quantify risperidone release. It has been demonstrated that the release rate of risperidone can be altered through the application, or absence, of electrical stimulation. Technology such as this would find use in drug-delivering implants where the dose could be adjusted through application of external stimulus, optimising benefit to side effect ratio, while simultaneously ensuring patient adherence (which is a particular challenge in mental health conditions).

  18. Dual drug-loaded nanoparticles on self-integrated scaffold for controlled delivery

    Directory of Open Access Journals (Sweden)

    Bennet D

    2012-07-01

    Full Text Available Devasier Bennet,1 Mohana Marimuthu,1 Sanghyo Kim,1 Jeongho An21Department of Bionanotechnology, Gachon University, Gyeonggi, Republic of Korea; 2Department of Polymer Science and Engineering, SunKyunKwan University, Gyeonggi, Republic of KoreaAbstract: Antioxidant (quercetin and hypoglycemic (voglibose drug-loaded poly-D,L-lactide-co-glycolide nanoparticles were successfully synthesized using the solvent evaporation method. The dual drug-loaded nanoparticles were incorporated into a scaffold film using a solvent casting method, creating a controlled transdermal drug-delivery system. Key features of the film formulation were achieved utilizing several ratios of excipients, including polyvinyl alcohol, polyethylene glycol, hyaluronic acid, xylitol, and alginate. The scaffold film showed superior encapsulation capability and swelling properties, with various potential applications, eg, the treatment of diabetes-associated complications. Structural and light scattering characterization confirmed a spherical shape and a mean particle size distribution of 41.3 nm for nanoparticles in the scaffold film. Spectroscopy revealed a stable polymer structure before and after encapsulation. The thermoresponsive swelling properties of the film were evaluated according to temperature and pH. Scaffold films incorporating dual drug-loaded nanoparticles showed remarkably high thermoresponsivity, cell compatibility, and ex vivo drug-release behavior. In addition, the hybrid film formulation showed enhanced cell adhesion and proliferation. These dual drug-loaded nanoparticles incorporated into a scaffold film may be promising for development into a transdermal drug-delivery system.Keywords: quercetin, voglibose, biocompatible materials, encapsulation, transdermal

  19. Controlled delivery of antiangiogenic drug to human eye tissue using a MEMS device

    KAUST Repository

    Pirmoradi, Fatemeh Nazly

    2013-01-01

    We demonstrate an implantable MEMS drug delivery device to conduct controlled and on-demand, ex vivo drug transport to human eye tissue. Remotely operated drug delivery to human post-mortem eyes was performed via a MEMS device. The developed curved packaging cover conforms to the eyeball thereby preventing the eye tissue from contacting the actuating membrane. By pulsed operation of the device, using an externally applied magnetic field, the drug released from the device accumulates in a cavity adjacent to the tissue. As such, docetaxel (DTX), an antiangiogenic drug, diffuses through the eye tissue, from sclera and choroid to retina. DTX uptake by sclera and choroid were measured to be 1.93±0.66 and 7.24±0.37 μg/g tissue, respectively, after two hours in pulsed operation mode (10s on/off cycles) at 23°C. During this period, a total amount of 192 ng DTX diffused into the exposed tissue. This MEMS device shows great potential for the treatment of ocular posterior segment diseases such as diabetic retinopathy by introducing a novel way of drug administration to the eye. © 2013 IEEE.

  20. β-Cyclodextrin grafted polypyrrole magnetic nanocomposites toward the targeted delivery and controlled release of doxorubicin

    Science.gov (United States)

    Hong, Shasha; Li, Zengbo; Li, Chenzhong; Dong, Chuan; Shuang, Shaomin

    2018-01-01

    The Fe3O4@PPy-HA-β-CD nanocomposites as the novel nanocarrier were prepared by grafting ethylenediamine derivative of​ β-​CD to the surface of polypyrrole-coated magnetic nanoparticles (Fe3O4@PPy) via using hyaluronan (HA) as the intermediate linker. HA was also the efficient target ligand for CD44. The as-prepared drug carrier was characterized by TEM, TGA, XRD, and VSM and used for the delivery of doxorubicin hydrochloride (DOX) with the high loading content of 447 mg/g. The multilayer Freundlich isotherm model was found to be a good fit for the loading of the drug carrier for DOX. Significant NIR-triggered release of DOX was observed in a weak acidic pH. And the release data in vitro was well described using the Retiger-Pepper kinetic model. Furthermore, MTT assay and confocal microscopy against Hep-G2 cells clearly illustrated that the drug carrier had no associated cytotoxicity and could easily enter the cells. The release and accumulation of DOX were observed in the cell nuclei. Thus, the DOX-loaded drug carrier killed the cancer cells efficaciously and minimized adverse side effects due to its target effect. These results suggested the as-prepared drug carrier would be of great potential for the controlled release and targeted delivery of DOX.

  1. Methods for synthesizing the macromolecular constituents of smart nanosized carriers for controlled drug delivery.

    Science.gov (United States)

    Balaure, Paul Catalin; Grumezescu, Alexandru Mihai

    2014-01-01

    Smart multifunctional polymeric nanocarriers able to respond to physicochemical changes in their environment or to external stimuli represent a new paradigm in the field of pharmaceutical formulations for controlled drug delivery. The introductory part of the present review deals with this new concept and presents the main advantages resulting from the use of such nanovehicles instead of conventional, much larger drug delivery systems. The access to drug nanocarriers based on smart supramolecular polymeric materials is primarily limited by the available polymerization methods capable to produce polymers with low polydispersity index, as well as much more complex macromolecular architectures with strictly controlled chemical composition, such as block copolymers and star or graft polymers or copolymers. This article reviews the state-of-the art in controlled/"living" free radical polymerization techniques as well as ring opening polymerization methods. Nitroxide mediated free radical polymerization (NMP), atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain-transfer polymerization (RAFT), single electron transfer-living radical polymerization (SET-LRP), single electron transfer-nitroxide radical coupling reaction (SET-NRC), cationic ring opening polymerization (CROP), anionic ring opening polymerization (AROP), and metal catalyzed ring opening polymerization are described, highlighting their mechanistic details and their synthetic potential as well as their limitations. The final part of the article is dedicated to a special type of unimolecular, monodisperse nanocarriers - the dendrimers. Both divergent and convergent approaches to dendrimer synthesis are described along with the therapeutic applications taking advantage of the unique branched tree-like globular structure of dendrimers to treat cancer.

  2. Use of an implantable pump for controlled subcutaneous insulin delivery in healthy cats.

    Science.gov (United States)

    Zini, E; Padrutt, I; Macha, K; Riederer, A; Pesaresi, M; Lutz, T A; Reusch, C E

    2017-01-01

    The aim of this study was to examine the safety and reliability of a research-grade implantable pump for controlled delivery of insulin glargine in cats. For this purpose, a small telemetrically controlled drug delivery pump with a refillable reservoir was implanted into the subcutaneous tissues of the dorsal neck in 10 clinically healthy cats. The reservoir was filled with insulin glargine, and the pump was programmed to deliver four boluses of 0.25 IU/kg, 2-3 weeks apart. As a control, insulin glargine (0.25 IU/kg) was injected SC. Blood glucose and plasma insulin glargine concentrations were measured before each bolus and SC injection and for 8 h afterward. Cats were monitored for signs of discomfort. Pumps were easily implanted and well tolerated by all cats. The experiment was completed in five of 10 cats. In four, the pump failed because of technical reasons; another cat developed severe hypoglycaemia attributable to insulin leakage. Overall, plasma insulin glargine increased after six of eight (75%) initial boluses and after one of 16 (6%) successive boluses. Glucose decreased after seven of eight (88%) initial boluses and after four of 16 (25%) successive boluses. Only the first bolus significantly increased plasma insulin glargine (P = 0.008) and decreased glucose (P = 0.008). Of 20 SC injections, 10 (50%) increased plasma insulin glargine (P pump did not cause discomfort in cats, but life-threatening hypoglycaemia occurred in one. Frequent device problems suggest that the pump needs improvements. Because successive boluses did not increase plasma insulin glargine, this type of insulin may not be appropriate with the pump. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Toward Understanding Mechanisms Controlling Urea Delivery in a Coastal Plain Watershed

    Science.gov (United States)

    Tzilkowski, S. S.; Buda, A. R.; Boyer, E. W.; Bryant, R. B.; May, E. B.

    2012-12-01

    Improved understanding of nutrient mobilization and delivery to surface waters is critical to protecting water quality in agricultural watersheds. Urea, a form of organic nitrogen, is a common nutrient found in fertilizers, manures, and human waste, and is gaining recognition as an important driver of coastal eutrophication, particularly through the development of harmful algal blooms. While several studies have documented elevated urea concentrations in tributaries draining to the Chesapeake Bay, little is known about the potential sources and flow pathways responsible for urea delivery from the landscape to surface waters, as well as how these sources and pathways might vary with changing seasons, antecedent conditions, and storm types. In this study, we investigated hydrologic controls on urea delivery in the Manokin River watershed through the analysis of urea concentration dynamics and hysteresis patterns during seven storm events that occurred in 2010 and 2011. The Manokin River is a Coastal Plain watershed (11.1 km2) on the Delmarva Peninsula that drains directly to the Chesapeake Bay and is characterized by extensive rural development coupled with intensive agriculture, particularly poultry production. Sampling was conducted through monthly grab sampling at baseflow conditions and by time-weighted, automated (Sigma) samplers during stormflow events. Monitored storms were chosen to represent a spectrum of antecedent conditions based on precipitation and groundwater levels in the area. Flushing from the landscape during events was found to be the predominant urea delivery mechanism, as urea concentrations increased 3-9 times above baseflow concentrations during storms. The timing and number of flushes, as well as the degree of increased concentrations were dependent on antecedent conditions and the characteristics of the storm event. For instance, during an intense (13.7 mm hr-1), short-duration (4 hrs) storm in August of 2010 when antecedent conditions were

  4. Efficacy and tolerability of intravenous morphine patient-controlled analgesia (PCA) in women undergoing cesarean delivery.

    Science.gov (United States)

    Andziak, Marta; Beta, Jarosław; Barwijuk, Michal; Issat, Tadeusz; Jakimiuk, Artur J

    2015-06-01

    The aim of the study was to evaluate analgesic efficacy and tolerability of patient-controlled analgesia (PCA) with intravenous morphine. Our observational study included 50 women who underwent a Misgav-Ladach or modified Misgav-Ladach cesarean section. Automated PCA infusion device (Medima S-PCA Syringe Pump, Medima, Krakow, Poland) was used for postoperative pain control. Time of morphine administration or initiation of intravenous patient-controlled analgesia (IV PCA) with morphine was recorded, as well as post-operative pain at rest assessed by a visual analogue scale (VAS). All patients were followed up for 24 hours after discharge from the operating room, taking into account patient records, worst pain score at rest, number of IV PCA attempts, and drug consumption. Median of total morphine doses used during the postoperative period was 42.9mg (IQR 35.6-48.5), with median infusion time of 687.0 min. (IQR 531.0-757.5). Pain severity and total drug consumption improved after the first 3 hours following cesarean delivery (p PCA attempts per patient was 33 (IQR: 24-37), with median of 11 placebo attempts (IQR: 3-27). Patient-controlled analgesia with morphine is an efficient and acceptable analgesic method in women undergoing cesarean section.

  5. Controlled power delivery for super-resolution imaging of biological samples using digital micromirror device

    Science.gov (United States)

    Valiya Peedikakkal, Liyana; Cadby, Ashley

    2017-02-01

    Localization based super resolution images of a biological sample is generally achieved by using high power laser illumination with long exposure time which unfortunately increases photo-toxicity of a sample, making super resolution microscopy, in general, incompatible with live cell imaging. Furthermore, the limitation of photobleaching reduces the ability to acquire time lapse images of live biological cells using fluorescence microscopy. Digital Light Processing (DLP) technology can deliver light at grey scale levels by flickering digital micromirrors at around 290 Hz enabling highly controlled power delivery to samples. In this work, Digital Micromirror Device (DMD) is implemented in an inverse Schiefspiegler telescope setup to control the power and pattern of illumination for super resolution microscopy. We can achieve spatial and temporal patterning of illumination by controlling the DMD pixel by pixel. The DMD allows us to control the power and spatial extent of the laser illumination. We have used this to show that we can reduce the power delivered to the sample to allow for longer time imaging in one area while achieving sub-diffraction STORM imaging in another using higher power densities.

  6. Halloysite nanotubes-polymeric nanocomposites: characteristics, modifications and controlled drug delivery approaches

    Directory of Open Access Journals (Sweden)

    P. C. Ferrari

    Full Text Available Abstract Halloysite nanotubes (HNTs are aluminosilicate nanoclay mineral which have a hollow tubular structure and occurs naturally. They are biocompatible and viable carrier for inclusion of biologically active molecules due to the empty space inside the tubular structure. In this article, the HNTs main characteristics, and the HNTs-polymeric nanocomposite formation and their potential application as improvement of the mechanical performance of polymers and entrapment of hydrophilic and lipophilic substances are summarized. Recent works covering the increment of HNTs-polymeric nanocomposites and presenting promising employment of these systems as nanosized carrier, being suitable for pharmaceutical and biomedical applications, based on earlier evidence in literature of its nature to sustain the release of loaded drugs, presenting low cytotoxicity, and providing evidence for controlled drug delivery are reviewed.

  7. AnIn-vitroInvestigation of Swelling Controlled Delivery of Insulin from Egg Albumin Nanocarriers.

    Science.gov (United States)

    Mahobia, Swati; Bajpai, Jaya; Bajpai, Anil Kumar

    2016-01-01

    The aim of the present work was to prepare and characterize biopolymer nanocarriers and evaluate their suitability in possible oral delivery of insulin. The egg albumin biopolymer was used to prepare nanoparticles which were further characterized by Fourier transformed Infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), zeta potential, Dynamic Light scattering (DLS) and cytotoxicity. From the characterization studies the size of the nanoparticles washemoly found to lie in the range 20-80 nm with surface charge of -23 mV and also offering extremely fair biocompatibility.. The in-vitro biocompatibility of the prepared nanocarriers was judged by BSA adsorption test and haemolysis assay. The in vitro release kinetics of the insulin loaded nanoparticles was studied in phosphate buffer saline (PBS) solution, and the influence of various factors such as pH, temperature and simulated physiological fluids was studied on the controlled release of insulin.

  8. Oscillations-free PID control of anesthetic drug delivery in neuromuscular blockade.

    Science.gov (United States)

    Medvedev, Alexander; Zhusubaliyev, Zhanybai T; Rosén, Olov; Silva, Margarida M

    2016-07-25

    The PID-control of drug delivery or the neuromuscular blockade (NMB) in closed-loop anesthesia is considered. The NMB system dynamics portrayed by a Wiener model can exhibit sustained nonlinear oscillations under realistic PID gains and for physiologically feasible values of the model parameters. Such oscillations, also repeatedly observed in clinical trials, lead to under- and over-dosing of the administered drug and undermine patient safety. This paper proposes a tuning policy for the proportional PID gain that via bifurcation analysis ensures oscillations-free performance of the control loop. Online estimates of the Wiener model parameters are needed for the controller implementation and monitoring of the closed-loop proximity to oscillation. The nonlinear dynamics of the PID-controlled NMB system are studied by bifurcation analysis. A database of patient models estimated under PID-controlled neuromuscular blockade during general anesthesia is utilized, along with the corresponding clinical measurements. The performance of three recursive algorithms is compared in the application at hand: an extended Kalman filter, a conventional particle filter (PF), and a PF making use of an orthonormal basis to estimate the probability density function from the particle set. It is shown that with a time-varying proportional PID gain, the type of equilibria of the closed-loop system remains the same as in the case of constant controller gains. The recovery time and frequency of oscillations are also evaluated in simulation over the database of patient models. Nonlinear identification techniques based on model linearization yield biased parameter estimates and thus introduce superfluous uncertainty. The bias and variance of the estimated models are related to the computational complexity of the identification algorithms, highlighting the superiority of the PFs in this safety-critical application. The study demonstrates feasibility of the proposed oscillation-free control

  9. Controlling drug delivery kinetics from mesoporous titania thin films by pore size and surface energy

    Directory of Open Access Journals (Sweden)

    Karlsson J

    2015-07-01

    Full Text Available Johan Karlsson, Saba Atefyekta, Martin Andersson Department of Chemical and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden Abstract: The osseointegration capacity of bone-anchoring implants can be improved by the use of drugs that are administrated by an inbuilt drug delivery system. However, to attain superior control of drug delivery and to have the ability to administer drugs of varying size, including proteins, further material development of drug carriers is needed. Mesoporous materials have shown great potential in drug delivery applications to provide and maintain a drug concentration within the therapeutic window for the desired period of time. Moreover, drug delivery from coatings consisting of mesoporous titania has shown to be promising to improve healing of bone-anchoring implants. Here we report on how the delivery of an osteoporosis drug, alendronate, can be controlled by altering pore size and surface energy of mesoporous titania thin films. The pore size was varied from 3.4 nm to 7.2 nm by the use of different structure-directing templates and addition of a swelling agent. The surface energy was also altered by grafting dimethylsilane to the pore walls. The drug uptake and release profiles were monitored in situ using quartz crystal microbalance with dissipation (QCM-D and it was shown that both pore size and surface energy had a profound effect on both the adsorption and release kinetics of alendronate. The QCM-D data provided evidence that the drug delivery from mesoporous titania films is controlled by a binding–diffusion mechanism. The yielded knowledge of release kinetics is crucial in order to improve the in vivo tissue response associated to therapeutic treatments. Keywords: mesoporous titania, controlled drug delivery, release kinetics, alendronate, QCM-D

  10. Research support for effective state and community tobacco control programme response to electronic nicotine delivery systems.

    Science.gov (United States)

    Schmitt, Carol L; Lee, Youn Ok; Curry, Laurel E; Farrelly, Matthew C; Rogers, Todd

    2014-07-01

    To identify unmet research needs of state and community tobacco control practitioners pertaining to electronic nicotine delivery systems (ENDS or e-cigarettes) that would inform policy and practice efforts at the state and community levels, and to describe ENDS-related research and dissemination activities of the National Cancer Institute-funded State and Community Tobacco Control Research Initiative. To determine specific research gaps relevant to state and community tobacco control practice, we analysed survey data collected from tobacco control programmes (TCPs) in all 50 U.S. states and the District of Columbia (N=51). Survey items covered a range of ENDS issues: direct harm to users, harm of secondhand vapour, cessation, flavours, constituents and youth access. There is no ENDS topic on which a majority of state TCP managers feel very informed. They feel least informed about harms of secondhand vapour while also reporting that this information is among the most important for their programme. A majority (N=31) of respondents indicated needs for research on the implications of ENDS products for existing policies. TCP managers report that ENDS research is highly important for practice and need research-based information to inform decision making around the inclusion of ENDS in existing tobacco control policies. For optimal relevance to state and community TCPs, research on ENDS should prioritise study of the health effects of ENDS use and secondhand exposure to ENDS vapour in the context of existing tobacco control policies. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  11. Formation of failure matrix and failure-free control algorithm for multi-sectioned Switched-reluctance drive

    Science.gov (United States)

    Odnokopylov, G.; Rozayev, I.

    2014-10-01

    We review fault-tolerant switched reluctance drive with sectioning of the three-phase stator winding. In the operating process of an electric drive, there will be continuous monitoring of the operating state on the basis of a developed algorithm to analyse drive operability and formation tabulate a failure matrix. The paper introduces a failure-free control algorithm for multi-section switch - reluctance motor with formation the assignment values of amplitude phase currents taking into account the failure matrix. We show that in an emergency such single failure or multiple failure in switched-reluctance drive it is possible to provide reduction of torque fall and pro-gressively stock depletion with providing fault-tolerance of drive system. A method of residual life evaluation is proposed on the basis of calculating the coefficient of operability of the electric drive system that gives possibility to control the endurance of electric drive in real time from operational to completely unusable.

  12. Tyrosine-derived polycarbonate-silica xerogel nanocomposites for controlled drug delivery.

    Science.gov (United States)

    Costache, M C; Vaughan, A D; Qu, H; Ducheyne, P; Devore, D I

    2013-05-01

    Biodegradable polymer-ceramic composites offer significant potential advantages in biomedical applications where the properties of either polymers or ceramics alone are insufficient to meet performance requirements. Here we demonstrate the highly tunable mechanical and controlled drug delivery properties accessible with novel biodegradable nanocomposites prepared by non-covalent binding of silica xerogels and co-polymers of tyrosine-poly(ethylene glycol)-derived poly(ether carbonate). The Young's moduli of the nanocomposites exceed by factors of 5-20 times those of the co-polymers or of composites made with micron scale silica particles. Increasing the fraction of xerogel in the nanocomposites increases the glass transition temperature and the mechanical strength, but decreases the equilibrium water content, which are all indicative of strong non-covalent interfacial interactions between the co-polymers and the silica nanoparticles. Sustained, tunable controlled release of both hydrophilic and hydrophobic therapeutic agents from the nanocomposites is demonstrated with two clinically significant drugs, rifampicin and bupivacaine. Bupivacaine exhibits an initial small burst release followed by slow release over the 7 day test period. Rifampicin release fits the diffusion-controlled Higuchi model and the amount released exceeds the dosage required for treatment of clinically challenging infections. These nanocomposites are thus attractive biomaterials for applications such as wound dressings, tissue engineering substrates and stents. Published by Elsevier Ltd.

  13. Hydroxypropylcellulose controlled release tablet matrix prepared by wet granulation: effect of powder properties and polymer composition

    Directory of Open Access Journals (Sweden)

    Antonio Zenon Antunes Teixeira

    2009-02-01

    Full Text Available The aim of this study was to attain 100% drug release of caffeine after 24 h from hydroxypropylcellulose (HPC tablet matrices and to investigate the effect of co-excipient. Physical properties of the powders were evaluated and suggested for a wet granulation process. The tablet containing caffeine was formulated by different weight ratios of hydrophilic polymers. The results of polymer evaluation confirmed that the increase of HPC level with the same drug content significantly decreased the rate of drug release. The presence of co-polymer excipients carboxymethylcellulose (CMC and polyvinylpyrrolidone (PVP in the tablet matrix was also investigated. The release rate was also controlled by low levels of CMC (O objetivo deste estudo é desenvolver a liberação 100% da droga cafeína em 24 horas em comprimidos matrizes e investigar o uso de hidroxipropilcelulose (HPC mais os efeitos de co-excipiente. As propriedades físicas dos pós foram avaliadas assim como seu uso no processo de granulação úmida. O comprimido contendo a cafeína foi formulado por diferentes relações de peso dos polímeros hidrofílicos. Os resultados da avaliação do polímero confirmaram que o aumento do nível de HPC com o mesmo índice da droga diminuiu significativamente a taxa de liberação da droga. A presença do co-polímero excipiente carboximetilcelulose (CMC e do polivinilpirrolidona (PVP na matriz do comprimido foi também investigado. A taxa de liberação foi controlada principalmente por baixos níveis de CMC (< 10% enquanto PVP não mostrou efeito diferente considerável. A melhor taxa de liberação de cafeína 100% em 24 horas foi obtida quando 10% da lactose monoidrato foi adicionado na formulação.

  14. Matrix Metalloproteinase-9 Controls NMDA Receptor Surface Diffusion through Integrin beta 1 Signaling

    NARCIS (Netherlands)

    Michaluk, Piotr; Mikasova, Lenka; Groc, Laurent; Frischknecht, Renato; Choquet, Daniel; Kaczmarek, Leszek

    2009-01-01

    Matrix metalloproteinase-9 (MMP-9) has emerged as a physiological regulator of NMDA receptor (NMDAR)-dependent synaptic plasticity and memory. The pathways by which MMP-9 affects NMDAR signaling remain, however, elusive. Using single quantum dot tracking, we demonstrate that MMP-9 enzymatic activity

  15. Cytoskeletal filament assembly and the control of cell spreading and function by extracellular matrix

    Science.gov (United States)

    Mooney, D. J.; Langer, R.; Ingber, D. E.

    1995-01-01

    This study was undertaken to analyze how cell binding to extracellular matrix produces changes in cell shape. We focused on the initial process of cell spreading that follows cell attachment to matrix and, thus, cell 'shape' changes are defined here in terms of alterations in projected cell areas, as determined by computerized image analysis. Cell spreading kinetics and changes in microtubule and actin microfilament mass were simultaneously quantitated in hepatocytes plated on different extracellular matrix substrata. The initial rate of cell spreading was highly dependent on the matrix coating density and decreased from 740 microns 2/h to 50 microns 2/h as the coating density was lowered from 1000 to 1 ng/cm2. At approximately 4 to 6 hours after plating, this initial rapid spreading rate slowed and became independent of the matrix density regardless of whether laminin, fibronectin, type I collagen or type IV collagen was used for cell attachment. Analysis of F-actin mass revealed that cell adhesion to extracellular matrix resulted in a 20-fold increase in polymerized actin within 30 minutes after plating, before any significant change in cell shape was observed. This was followed by a phase of actin microfilament disassembly which correlated with the most rapid phase of cell extension and ended at about 6 hours; F-actin mass remained relatively constant during the slow matrix-independent spreading phase. Microtubule mass increased more slowly in spreading cells, peaking at 4 hours, the time at which the transition between rapid and slow spreading rates was observed. However, inhibition of this early rise in microtubule mass using either nocodazole or cycloheximide did not prevent this transition. Use of cytochalasin D revealed that microfilament integrity was absolutely required for hepatocyte spreading whereas interference with microtubule assembly (using nocodazole or taxol) or protein synthesis (using cycloheximide) only partially suppressed cell extension. In

  16. Cytoskeletal filament assembly and the control of cell spreading and function by extracellular matrix.

    Science.gov (United States)

    Mooney, D J; Langer, R; Ingber, D E

    1995-06-01

    This study was undertaken to analyze how cell binding to extracellular matrix produces changes in cell shape. We focused on the initial process of cell spreading that follows cell attachment to matrix and, thus, cell 'shape' changes are defined here in terms of alterations in projected cell areas, as determined by computerized image analysis. Cell spreading kinetics and changes in microtubule and actin microfilament mass were simultaneously quantitated in hepatocytes plated on different extracellular matrix substrata. The initial rate of cell spreading was highly dependent on the matrix coating density and decreased from 740 microns 2/h to 50 microns 2/h as the coating density was lowered from 1000 to 1 ng/cm2. At approximately 4 to 6 hours after plating, this initial rapid spreading rate slowed and became independent of the matrix density regardless of whether laminin, fibronectin, type I collagen or type IV collagen was used for cell attachment. Analysis of F-actin mass revealed that cell adhesion to extracellular matrix resulted in a 20-fold increase in polymerized actin within 30 minutes after plating, before any significant change in cell shape was observed. This was followed by a phase of actin microfilament disassembly which correlated with the most rapid phase of cell extension and ended at about 6 hours; F-actin mass remained relatively constant during the slow matrix-independent spreading phase. Microtubule mass increased more slowly in spreading cells, peaking at 4 hours, the time at which the transition between rapid and slow spreading rates was observed. However, inhibition of this early rise in microtubule mass using either nocodazole or cycloheximide did not prevent this transition. Use of cytochalasin D revealed that microfilament integrity was absolutely required for hepatocyte spreading whereas interference with microtubule assembly (using nocodazole or taxol) or protein synthesis (using cycloheximide) only partially suppressed cell extension. In

  17. Controlled production of ZnO nanoparticles from zinc glycerolate in a sol-gel silica matrix.

    Science.gov (United States)

    Moleski, Rodoula; Leontidis, Epameinondas; Krumeich, Frank

    2006-10-01

    The controlled production of ZnO nanoparticles within an amorphous silica matrix is achieved using a new methodology consisting of four stages. First, precursor zinc glycerolate nanoparticles are produced within reversed micelles of glycerol in heptane stabilized by the surfactant Aerosol-OT (bis-ethylhexyl sodium sulfosuccinate, AOT). The surface of these nanoparticles is then modified by exchanging AOT with bis-trimethoxysilyl-ethane (BTME). The surface-modified nanoparticles are copolymerized with tetramethoxysilane (TMOS) to provide a composite silica material, in which the nanoparticles are apparently dissolved, producing a uniform distribution of zinc in the silica matrix. Finally, the conversion of zinc to ZnO is achieved by heating the material at 700 degrees C, leading to a uniform dispersion of very small (amorphous matrix. The fluorescence spectrum of the ZnO particles within the matrix is blue-shifted, as expected from the strong quantum confinement achieved. The properties of the system at all stages in this synthetic process are monitored using TEM, XRD, fluorescence and FT-IR spectroscopy. Glycerol forms complexes with many metal ions, so the present procedure may be generalized to provide uniform distributions of metal ions and subsequently metal oxide nanoparticles in amorphous silica.

  18. Evaluation of hyaluronic matrix efficacy in sinus augmentation: a randomized-controlled histomorphometric and micro-computed tomography analysis.

    Science.gov (United States)

    Dogan, E; Dursun, E; Tosun, E; Bilgic, E; Akman, A C; Orhan, K; Celik, H H; Korkusuz, P; Caglayan, F

    2017-07-01

    The objective of the present study was to test the hypothesis that the addition of hyaluronic acid-based matrix to collagenated heterologous bone graft for sinus augmentation would enhance bone formation compared to collagenated heterologous bone graft alone in the early healing period, by micro-computed tomography and histomorphometry. Thirteen systemically healthy patients requiring bilateral two-stage maxillary sinus augmentation (residual crest height≤4mm) were enrolled in this split-mouth prospective randomized controlled study. One sinus side as a control group was grafted with only collagenated heterologous bone graft; the other region as a test group was grafted with hyaluronic matrix and collagenated heterologous bone graft. Bone biopsy samples were taken after 4 months during the dental implant surgery and analyzed using micro-computed tomography and histomorphometric parameters. According to the micro-computed tomography and histomorphometric results, a significantly higher percentage of new bone was observed in the test group when compared to the control group after 4 months of healing. This study confirmed the hypothesis that the addition of hyaluronic matrix to collagenated heterologous bone graft for sinus augmentation enhances bone formation compared to collagenated heterologous bone graft alone in the early healing period. Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  19. Design and Characterization of Mesalamine Loaded Nanoparticles for Controlled Delivery System

    Directory of Open Access Journals (Sweden)

    Simin Seifirad

    2016-10-01

    Full Text Available Objective(s: Nanoparticles (NPs are known for their specific accumulation in the inflamed tissues of the colon and thus allow a selective delivery to the site of inflammation with minimum adverse effects. The main objective of this work is to attain mesalamine loaded chitosan nanoparticles as a carrier for oral delivery. Methods: In this study, mesalamine loaded chitosan nanoparticles were prepared using an ionic gelation method. Experimental design Box-Behnken response surface methodology was used for the optimization of the nanoparticles. The nanoparticles size and gelation process of the polymeric nano-drug controlled release system depends on several variables including the concentration ratio of chitosan-TPP, concentration of mesalamine, concentration of chitosan solution and pH of the solution with optimum conditions of 2.3, 0.02 mg/ml, 0.1 mg/ml and 4.5, respectively. Results: The mean particle size of the synthesized nanoparticles was ranging from 53.9 to 322.8 nm using a dynamic light scattering (DLS technique. Moreover, the morphology of the prepared nanoparticles was observed by scanning electron microscopy (SEM. Also, characterization of the chitosan-mesalamine nanoparticles was performed by FT-IR spectrophotometer for specifying the chemical structure of nanoparticles molecules and differential scanning calorimetry (DSC for studying thermal behavior. Drug release profile and the amount of the loaded drug were also monitored by UV-Vis spectroscopy. Conclusions: Drug released showed that the release profile of mesalamine loaded nanoparticles was in a slow manner and no initial rapid release (burst effect was illustrated.

  20. pH-responsive CAP-co-poly(methacrylic acid)-based hydrogel as an efficient platform for controlled gastrointestinal delivery: fabrication, characterization, in vitro and in vivo toxicity evaluation.

    Science.gov (United States)

    Shah, Syed Ahmed; Sohail, Muhammad; Minhas, Muhammad Usman; Nisar-Ur-Rehman; Khan, Shahzeb; Hussain, Zahid; Mudassir; Mahmood, Arshad; Kousar, Mubeen; Mahmood, Asif

    2018-02-15

    Cellulose acetate phthalate-based pH-responsive hydrogel was synthesized for fabrication of polymeric matrix tablets for gastro-protective delivery of loxoprofen sodium. Cellulose acetate phthalate (CAP) was cross-linked with methacrylic acid (MAA) using free radical polymerization technique. Fourier transform infrared (FTIR) spectra confirmed the formation of cross-linked structure of CAP-co-poly(methacrylic acid). Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the thermal stability of polymeric networks, and scanning electron microscopy (SEM) and energy-dispersive X-ray spectrum (EDS) images unveiled that the prepared formulations were porous in nature and thus the developed formulations had shown better diffusibility. Swelling and in vitro drug release was performed at various pHs and maximum swelling and release was obtained at pH 7.4, while swelling and release rate was very low at pH 1.2 which confirmed the pH-responsive behavior of CAP-co-poly(MAA). CAP-co-poly(MAA) copolymer prevents the release of loxoprofen sodium into the stomach due to reduced swelling at gastric pH while showing significant swelling and drug release in the colon. Cytotoxicity studies revealed higher biocompatibility of fabricated hydrogel. Acute oral toxicity studies were performed for the evaluation and preliminary screening of safety profile of the developed hydrogels. Matrix tablets were evaluated for release behavior at simulated body pH. The investigations performed for analysis of hydrogels and fabricated matrix tablets indicated the controlled drug release and gastro-protective drug delivery of CAP-co-poly(MAA) hydrogels and pH-sensitive matrix tablets for targeted delivery of gastro-sensitive/irritative agents. Graphical abstract ᅟ.

  1. Urinary incontinence during pregnancy and 1 year after delivery in primiparous women compared with a control group of nulliparous women

    DEFF Research Database (Denmark)

    Hansen, Bent Brandt; Svare, Jens; Viktrup, Lars

    2012-01-01

    AIMS: To investigate the impact of the first pregnancy and delivery on the prevalence and types of urinary incontinence during pregnancy and 1 year after delivery. METHODS: The study was a prospective cohort study with a control group. Primiparous women, who delivered in our department from June...... 2003 to July 2005, participated. The women filled out a questionnaire 2-3 days after the delivery and a new questionnaire after 1 year. The questionnaires comprised basic characteristics and symptoms of urinary incontinence. An attempted age-matched control group of nulliparous women was included......, and filled out similar questionnaires. Prevalences and types of urinary incontinence, and a combined severity- and bother-score (ICIQ-SF score) among the incontinent women, were calculated and compared. RESULTS: The two groups differed significantly in age and most basic characteristics. During pregnancy...

  2. Robust extraction of basis functions for simultaneous and proportional myoelectric control via sparse non-negative matrix factorization.

    Science.gov (United States)

    Lin, Chuang; Wang, Binghui; Jiang, Ning; Farina, Dario

    2018-04-01

    This paper proposes a novel simultaneous and proportional multiple degree of freedom (DOF) myoelectric control method for active prostheses. The approach is based on non-negative matrix factorization (NMF) of surface EMG signals with the inclusion of sparseness constraints. By applying a sparseness constraint to the control signal matrix, it is possible to extract the basis information from arbitrary movements (quasi-unsupervised approach) for multiple DOFs concurrently. In online testing based on target hitting, able-bodied subjects reached a greater throughput (TP) when using sparse NMF (SNMF) than with classic NMF or with linear regression (LR). Accordingly, the completion time (CT) was shorter for SNMF than NMF or LR. The same observations were made in two patients with unilateral limb deficiencies. The addition of sparseness constraints to NMF allows for a quasi-unsupervised approach to myoelectric control with superior results with respect to previous methods for the simultaneous and proportional control of multi-DOF. The proposed factorization algorithm allows robust simultaneous and proportional control, is superior to previous supervised algorithms, and, because of minimal supervision, paves the way to online adaptation in myoelectric control.

  3. Robust extraction of basis functions for simultaneous and proportional myoelectric control via sparse non-negative matrix factorization

    Science.gov (United States)

    Lin, Chuang; Wang, Binghui; Jiang, Ning; Farina, Dario

    2018-04-01

    Objective. This paper proposes a novel simultaneous and proportional multiple degree of freedom (DOF) myoelectric control method for active prostheses. Approach. The approach is based on non-negative matrix factorization (NMF) of surface EMG signals with the inclusion of sparseness constraints. By applying a sparseness constraint to the control signal matrix, it is possible to extract the basis information from arbitrary movements (quasi-unsupervised approach) for multiple DOFs concurrently. Main Results. In online testing based on target hitting, able-bodied subjects reached a greater throughput (TP) when using sparse NMF (SNMF) than with classic NMF or with linear regression (LR). Accordingly, the completion time (CT) was shorter for SNMF than NMF or LR. The same observations were made in two patients with unilateral limb deficiencies. Significance. The addition of sparseness constraints to NMF allows for a quasi-unsupervised approach to myoelectric control with superior results with respect to previous methods for the simultaneous and proportional control of multi-DOF. The proposed factorization algorithm allows robust simultaneous and proportional control, is superior to previous supervised algorithms, and, because of minimal supervision, paves the way to online adaptation in myoelectric control.

  4. Targeted and controlled anticancer drug delivery and release with magnetoelectric nanoparticles

    Science.gov (United States)

    Rodzinski, Alexandra; Guduru, Rakesh; Liang, Ping; Hadjikhani, Ali; Stewart, Tiffanie; Stimphil, Emmanuel; Runowicz, Carolyn; Cote, Richard; Altman, Norman; Datar, Ram; Khizroev, Sakhrat

    2016-02-01

    It is a challenge to eradicate tumor cells while sparing normal cells. We used magnetoelectric nanoparticles (MENs) to control drug delivery and release. The physics is due to electric-field interactions (i) between MENs and a drug and (ii) between drug-loaded MENs and cells. MENs distinguish cancer cells from normal cells through the membrane’s electric properties; cancer cells have a significantly smaller threshold field to induce electroporation. In vitro and in vivo studies (nude mice with SKOV-3 xenografts) showed that (i) drug (paclitaxel (PTX)) could be attached to MENs (30-nm CoFe2O4@BaTiO3 nanostructures) through surface functionalization to avoid its premature release, (ii) drug-loaded MENs could be delivered into cancer cells via application of a d.c. field (~100 Oe), and (iii) the drug could be released off MENs on demand via application of an a.c. field (~50 Oe, 100 Hz). The cell lysate content was measured with scanning probe microscopy and spectrophotometry. MENs and control ferromagnetic and polymer nanoparticles conjugated with HER2-neu antibodies, all loaded with PTX were weekly administrated intravenously. Only the mice treated with PTX-loaded MENs (15/200 μg) in a field for three months were completely cured, as confirmed through infrared imaging and post-euthanasia histology studies via energy-dispersive spectroscopy and immunohistochemistry.

  5. Photo-controlled aptamers delivery by dual surface gold-magnetic nanoparticles for targeted cancer therapy.

    Science.gov (United States)

    Zhao, Jian; Tu, Keyao; Liu, Yanlei; Qin, Yulei; Wang, Xiwei; Qi, Lifeng; Shi, Donglu

    2017-11-01

    Dual surfaced dumbbell-like gold magnetic nanoparticles (Au-Fe 3 O 4 ) were synthesized for targeted aptamers delivery. Their unique biological properties were characterized as a smart photo-controlled drug carrier. DNA aptamers targeting vascular endothelial growth factor (VEGF) were assembled onto the surface of Au-Fe 3 O 4 by electrostatic absorption. The binding capacity of the nanoparticles with VEGF aptamers was confirmed by gel electrophoresis. The targeted recognization of ovarian cancer cells by the aptamers-functionalized Au-Fe 3 O 4 nanoparticles (Apt-Au-Fe 3 O 4 NPs) was observed by confocal microscopy. Apt-Au-Fe 3 O 4 was found to bind with SKOV-3 ovarian cancer cells specifically, leading to marked intracellular release of aptamers upon plasmon-resonant light (605nm) radiation, and to enhance the in vitro inhibition against tumor cell proliferation. The results show high potential of Apt-Au-Fe 3 O 4 as a targeted cancer hyperthermia carrier by remote control with high spatial/temporal resolution. Copyright © 2017. Published by Elsevier B.V.

  6. pH-Responsive PLGA Nanoparticle for Controlled Payload Delivery of Diclofenac Sodium

    Directory of Open Access Journals (Sweden)

    Shalil Khanal

    2016-08-01

    Full Text Available Poly(lactic-co-glycolic acid (PLGA based nanoparticles have gained increasing attention in delivery applications due to their capability for controlled drug release characteristics, biocompatibility, and tunable mechanical, as well as degradation, properties. However, thorough study is always required while evaluating potential toxicity of the particles from dose dumping, inconsistent release and drug-polymer interactions. In this research, we developed PLGA nanoparticles modified by chitosan (CS, a cationic and pH responsive polysaccharide that bears repetitive amine groups in its backbone. We used a model drug, diclofenac sodium (DS, a nonsteroidal anti-inflammatory drug (NSAID, to study the drug loading and release characteristics. PLGA nanoparticles were synthesized by double-emulsion solvent evaporation technique. The nanoparticles were evaluated based on their particle size, surface charge, entrapment efficacy, and effect of pH in drug release profile. About 390–420 nm of average diameters and uniform morphology of the particles were confirmed by scanning electron microscope (SEM imaging and dynamic light scattering (DLS measurement. Chitosan coating over PLGA surface was confirmed by FTIR and DLS. Drug entrapment efficacy was up to 52%. Chitosan coated PLGA showed a pH responsive drug release in in vitro. The release was about 45% more at pH 5.5 than at pH 7.4. The results of our study indicated the development of chitosan coating over PLGA nanoparticle for pH dependent controlled release DS drug for therapeutic applications.

  7. Relationship between tobacco control policies and the delivery of smoking cessation services in nonprofit HMOs.

    Science.gov (United States)

    Stevens, Victor J; Solberg, Leif I; Quinn, Virginia P; Rigotti, Nancy A; Hollis, Jack A; Smith, K Sabina; Zapka, Jane G; France, Eric; Vogt, Thomas; Gordon, Nancy; Fishman, Paul; Boyle, Raymond G

    2005-01-01

    This project examined tobacco policies and delivery of cessation services in nonprofit HMOs that collectively provide comprehensive medical care to more than 8 million members. Three annual surveys with health plan managers showed that all of these health plans had written tobacco control guidelines that became more comprehensive over the span of this study. We also surveyed a random sample of 4207 current smokers who had attended a primary care visit in the past year (399-528 at each of nine health plans). Of these smokers, 71% reported advice to quit, 56% were asked about their willingness to quit, 49% were provided some assistance in quitting (mostly self-help material or information about classes or counseling), and 9% were offered some kind of follow-up. Smokers receiving assistance in quitting reported higher satisfaction with their care. In general, health plans with the most comprehensive policies also showed higher rates of implementing tobacco treatment programs in primary care. Compared with tobacco control efforts of a decade or more ago, considerable progress has been made. However, there is still room for improvement in the proportion of smokers who receive the most effective forms of assistance in quitting.

  8. Development and Optimization of Osmotically Controlled Asymmetric Membrane Capsules for Delivery of Solid Dispersion of Lycopene

    Directory of Open Access Journals (Sweden)

    Nitin Jain

    2014-01-01

    Full Text Available The aim of the present investigation is to develop and statistically optimize the osmotically controlled asymmetric membrane capsules of solid dispersion of lycopene. Solid dispersions of lycopene with β-cyclodextrin in different ratios were prepared using solvent evaporation method. Solubility studies showed that the solid dispersion with 1 : 5 (lycopene : β-cyclodextrin exhibited optimum solubility (56.25 mg/mL for osmotic controlled delivery. Asymmetric membrane capsules (AMCs were prepared on glass mold pins via dip coating method. Membrane characterization by scanning electron microscopy showed inner porous region and outer dense region. Central composite design response surface methodology was applied for the optimization of AMCs. The independent variables were ethyl cellulose (X1, glycerol (X2, and NaCl (X3 which were varied at different levels to analyze the effect on dependent variables (percentage of cumulative drug release (Y1 and correlation coefficient of drug release (Y2. The effect of independent variables on the response was significantly influential. The F18 was selected as optimized formulation based on percentage of CDR (cumulative drug release of 85.63% and correlation coefficient of 0.9994. The optimized formulation was subjected to analyze the effect of osmotic pressure and agitational intensity on percentage of CDR. The drug release was independent of agitational intensity but was dependent on osmotic pressure of dissolution medium.

  9. Premedication with midazolam prior to cesarean delivery in preeclamptic parturients: A randomized controlled trial

    Science.gov (United States)

    Mokhtar, Ali M.; Elsakka, Ahmed I.; Ali, Hassan M.

    2016-01-01

    Background: Anxiety is a concern in obstetrics, especially in preeclamptic mothers. Sedation is not commonly used in parturients for fear of adverse neonatal effect. We investigated maternal and neonatal outcome of midazolam as an adjuvant to spinal anesthesia for elective cesarean delivery. Methods: A prospective randomized controlled trial, in which eighty preeclamptic parturients received either an intravenous dose of 0.035 mg/kg of midazolam or an equal volume of normal saline, 30 min before spinal anesthesia. Maternal anxiety was assessed using Amsterdam Preoperative Anxiety and Information Scale (APAIS); postoperative maternal satisfaction was assessed using Maternal Satisfaction Scale for Cesarean Section (MSSCS). Newborns were assessed using Apgar score, Neonatal Neurologic and Adaptive Capacity Score (NACS), and umbilical artery blood gases. Results: Mothers premedicated with midazolam showed a lower level of preoperative anxiety and a higher degree of postoperative satisfaction than the control group. There were no between-group differences regarding the neonatal outcome. Conclusion: Preeclamptic parturients premedicated with midazolam (0.035 mg/kg) before spinal anesthesia have lower anxiety and higher postoperative satisfaction levels, with no adverse effects on the newborns. PMID:27746564

  10. Matrix stiffness modulates formation and activity of neuronal networks of controlled architectures.

    Science.gov (United States)

    Lantoine, Joséphine; Grevesse, Thomas; Villers, Agnès; Delhaye, Geoffrey; Mestdagh, Camille; Versaevel, Marie; Mohammed, Danahe; Bruyère, Céline; Alaimo, Laura; Lacour, Stéphanie P; Ris, Laurence; Gabriele, Sylvain

    2016-05-01

    The ability to construct easily in vitro networks of primary neurons organized with imposed topologies is required for neural tissue engineering as well as for the development of neuronal interfaces with desirable characteristics. However, accumulating evidence suggests that the mechanical properties of the culture matrix can modulate important neuronal functions such as growth, extension, branching and activity. Here we designed robust and reproducible laminin-polylysine grid micropatterns on cell culture substrates that have similar biochemical properties but a 100-fold difference in Young's modulus to investigate the role of the matrix rigidity on the formation and activity of cortical neuronal networks. We found that cell bodies of primary cortical neurons gradually accumulate in circular islands, whereas axonal extensions spread on linear tracks to connect circular islands. Our findings indicate that migration of cortical neurons is enhanced on soft substrates, leading to a faster formation of neuronal networks. Furthermore, the pre-synaptic density was two times higher on stiff substrates and consistently the number of action potentials and miniature synaptic currents was enhanced on stiff substrates. Taken together, our results provide compelling evidence to indicate that matrix stiffness is a key parameter to modulate the growth dynamics, synaptic density and electrophysiological activity of cortical neuronal networks, thus providing useful information on scaffold design for neural tissue engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Pectin/anhydrous dibasic calcium phosphate matrix tablets for in vitro controlled release of water-soluble drug.

    Science.gov (United States)

    Mamani, Pseidy Luz; Ruiz-Caro, Roberto; Veiga, María Dolores

    2015-10-15

    Different pectin/anhydrous dibasic calcium phosphate (ADCP) matrix tablets have been developed in order to obtain controlled release of a water-soluble drug (theophylline). Swelling, buoyancy and dissolution studies have been carried out in different aqueous media (demineralized water, progressive pH medium, simulated gastric fluid, simulated intestinal fluid and simulated colonic fluid), to characterize the matrix tablets. When the pectin/ADCP ratio was ≥0.26 (P1, P2, P3 and P4 tablets) a continuous swelling and low theophylline dissolution rate from the matrices were observed. So, pectin gel forming feature predominated over the ADCP properties, yielding pH-independent drug release behavior from these matrices. On the contrary, pectin/ADCP ratios ≤0.11 (P5 and P6 tablets) allowed to achieve drug dissolution pH dependent. Consequently, the suitable selection of the pectin/ADCP ratio will allow to tailor matrix tablets for controlled release of water-soluble drugs in a specific manner in the gastrointestinal tract. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Power Decoupling Method Based on the Diagonal Compensating Matrix for VSG-Controlled Parallel Inverters in the Microgrid

    Directory of Open Access Journals (Sweden)

    Bin Li

    2017-12-01

    Full Text Available The thought of the virtual synchronous generator (VSG for controlling the grid-connected inverters and providing virtual inertia to the microgrid is emerging as a wide extension of the droop control, power coupling that always exists in the low-voltage microgrid, which may deteriorate the dynamic response and the stability of the system. In this paper, the principle of VSG control is introduced first. As an important issue of VSG control, the mechanism of the power coupling in the low-voltage microgrid is analyzed and the small-signal equivalent model of the power transmission loop is established. Subsequently, a power decoupling method based on the diagonal compensating matrix for VSG is proposed, which can realize the power decoupling with no impact on the original control channel. Meanwhile, the feasibility analysis of the decoupling method and the improved approach for reactive power sharing are also discussed. Simulation results verify the effectiveness of the decoupling strategy for VSGs.

  13. Quality by Design approach to understand the physicochemical phenomena involved in controlled release of captopril SR matrix tablets.

    Science.gov (United States)

    Saurí, J; Millán, D; Suñé-Negre, J M; Colom, H; Ticó, J R; Miñarro, M; Pérez-Lozano, P; García-Montoya, E

    2014-12-30

    The aim of this study is to obtain swelling controlled release matrix tablets of captopril using the Quality by Design methodology (ICH Q8) and to know the transport mechanisms involved in captopril release. To obtain the area of knowledge, the design of experiments studying the effect of two components (HPMC K15M and ethylcellulose) at different levels has been applied, with the captopril dissolution profile as the product's most important critical quality attribute (CQA). Different dissolution profiles have been obtained with the design of experiments performed, which is a key factor in the development of controlled release matrix tablets. Kinetic analysis according to the equations of Higuchi and Korsmeyer-Peppas demonstrates that the release mechanism is a mechanism of erosion when the whole percentage of the polymer is ethylcellulose, and a diffusion mechanism when the whole percentage of the polymer is HPMC K15M. The physico-chemical characteristics of the gel layer determine the release rate of captopril. The thickness of the gel layer, the porosity which is formed in the matrix upon contact with water, pore size, the swelling rate, the erosion rate of the matrix, and the physico-chemical characteristics of captopril, are factors related to the kinetic equations described and that allow us to predict the release mechanism of captopril. A new relationship of the kinetic equations governing the in vitro behavior with the physical characteristics of the gel layer of the different formulations has been established. This study shows that the size of water-filled pores and the degree of crosslinking between the chains of HPMC K15M of the matrix are related to the exponent n of the Korsmeyer-Peppas equation and the type of transport of the captopril from within the matrix to the dissolution medium, that is, if the transport is only through water-filled pores, or if a combination of diffusion occurs through water-filled pores with a transport through continuous

  14. Speed and position sensorless control of permanent magnet synchronous motor in matrix converter and voltage source converter applications

    Energy Technology Data Exchange (ETDEWEB)

    Eskola, M.

    2006-07-01

    In this thesis the sensorless control of a permanent magnet synchronous motor (PMSM) is studied. The study has two main purposes. The first is to find a simple and effective method to estimate the rotor position and angular speed of the PMSM. The second is to test the applicability of a matrix converter in sensorless PMSM drives. A matrix converter (MC) enables a direct frequency conversion without DC-link with energy storage. In this thesis two matrix converter topologies, direct and indirect, are studied. The vector modulation and the current commutation strategies of a matrix converter are described. Non-ideal properties of frequency converters such as dead times, overlapping times and voltage losses over semiconductors are disturbances for a control system and position estimator. These non-idealities are studied and the properties of a conventional voltage source inverter are compared to direct and indirect MC topologies. The rotor position and angular speed of the PMSM can be estimated by various methods. Estimators can be divided into model based estimators and signal injection estimators. Model based estimators calculate mechanical quantities using the mathematical representation of the motor. Injection methods usually exploit the saliency of the PMSM. Injected voltage creates currents which are modulated by the rotor position. The position information can be extracted from measured currents. In this thesis the best features of model based and injection estimators are combined. In the proposed hybrid method signal injection is used at low speeds and the transition to model based estimator is performed when the speed increases. The estimator methods used in the hybrid estimator are selected by a comparative analysis and simulations. The most important criteria in the selection of the estimator method in this thesis are: simple algorithm and no need for modification of the modulator software or frequency converter. The suitability of the proposed hybrid

  15. The effects of mode of delivery and sex of newborn on placental morphology in control and diabetic pregnancies

    DEFF Research Database (Denmark)

    Mayhew, T M; Sørensen, Flemming Brandt; Klebe, J G

    1993-01-01

    Placentae from control and diabetic subjects were analysed using stereological techniques in order to assess the effects of mode of delivery (vaginal versus caesarean) and sex of neonate on parenchymal morphology. Effects were assessed using indices of peripheral villous and fetal capillary growt...

  16. Fabrication of a multifunctional nano-in-micro drug delivery platform by microfluidic templated encapsulation of porous silicon in polymer matrix.

    Science.gov (United States)

    Zhang, Hongbo; Liu, Dongfei; Shahbazi, Mohammad-Ali; Mäkilä, Ermei; Herranz-Blanco, Bárbara; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2014-07-09

    A multifunctional nano-in-micro drug delivery platform is developed by conjugating the porous silicon nanoparticles with mucoadhesive polymers and subsequent encapsulation into a pH-responsive polymer using microfluidics. The multistage platform shows monodisperse size distribution and pH-responsive payload release, and the released nanoparticles are mucoadhesive. Moreover, this platform is capable of simultaneously loading and releasing multidrugs with distinct properties. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Synthesis and characterization of biodegradable microcapsules for the controlled delivery of calcium hydroxide.

    Science.gov (United States)

    Han, Bing; Wang, Xiaoyan; Gao, Xuejun; Liu, Jiguang; Liang, Fuxin; Qu, Xiaozhong; Yang, Zhenzhong

    2011-10-01

    This study aimed to synthesize and characterize biodegradable microcapsules based on poly(lactic acid) (PLA) and ethylcellulose (EC) for a controlled delivery of calcium hydroxide. Phase separation technique was adopted to synthesize calcium hydroxide-loaded PLA/EC microcapsules. Four PLA/EC blends (4/1, 1/1, 1/4, pure EC) were used as shell materials and the input ratio of calcium hydroxide to shell polymer was 4:1 for all microcapsules. The morphology and composition were studied using SEM-EDS and TEM. Particle size distribution, glass-transition temperature, drug loading, and encapsulation efficiency were characterized. In vitro release of the microcapsules was evaluated using a pH microelectrode and an auto-biochemistry analyzer. SEM images of microcapsules showed uniform spherical structures with smooth surfaces. Core-shell, hetero-structures were confirmed using TEM. The presence of calcium in the microcapsules was verified with EDS. Pure calcium hydroxide was 160 nm in diameter and the particle size of the microcapsules ranged between 500 nm and 4 μm. With an increase of PLA in PLA/EC blend, the size of microcapsules increased accordingly. Encapsulation efficiency of these microcapsules was higher than 57% and drug loading was higher than 80%, which were not significantly different among four microcapsules. Pure calcium hydroxide powder was used as a control and 90% was released within 48 h, while release of calcium hydroxide from microcapsules took between 168 and 456 h, depending on the PLA/EC ratio. Compared with calcium hydroxide powder, the calcium hydroxide-loaded microcapsules showed a sustained and prolonged release, which could be controlled via the regulation of the PLA/EC ratio. Copyright © 2011 Wiley Periodicals, Inc.

  18. Scalable fabrication of size-controlled chitosan nanoparticles for oral delivery of insulin.

    Science.gov (United States)

    He, Zhiyu; Santos, Jose Luis; Tian, Houkuan; Huang, Huahua; Hu, Yizong; Liu, Lixin; Leong, Kam W; Chen, Yongming; Mao, Hai-Quan

    2017-06-01

    Controlled delivery of protein would find diverse therapeutic applications. Formulation of protein nanoparticles by polyelectrolyte complexation between the protein and a natural polymer such as chitosan (CS) is a popular approach. However, the current method of batch-mode mixing faces significant challenges in scaling up while maintaining size control, high uniformity, and high encapsulation efficiency. Here we report a new method, termed flash nanocomplexation (FNC), to fabricate insulin nanoparticles by infusing aqueous solutions of CS, tripolyphosphate (TPP), and insulin under rapid mixing condition (Re > 1600) in a multi-inlet vortex mixer. In comparison with the bulk-mixing method, the optimized FNC process produces CS/TPP/insulin nanoparticles with a smaller size (down to 45 nm) and narrower size distribution, higher encapsulation efficiency (up to 90%), and pH-dependent nanoparticle dissolution and insulin release. The CS/TPP/insulin nanoparticles can be lyophilized and reconstituted without loss of activity, and produced at a throughput of 5.1 g h -1 when a flow rate of 50 mL min -1 is used. Evaluated in a Type I diabetes rat model, the smaller nanoparticles (45 nm and 115 nm) control the blood glucose level through oral administration more effectively than the larger particles (240 nm). This efficient, reproducible and continuous FNC technique is amenable to scale-up in order to address the critical barrier of manufacturing for the translation of protein nanoparticles. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Matrix assisted pulsed laser evaporation of pullulan tailor-made biomaterial thin films for controlled drug delivery systems

    Czech Academy of Sciences Publication Activity Database

    Cristescu, R.; Jelínek, Miroslav; Kocourek, Tomáš; Axente, E.; Grigorescu, S.; Moldovan, A.; Mihaiescu, D.E.; Albulescu, M.; Buruiana, T.; Dybal, Jiří; Stamatin, I.; Mihailescu, I. N.; Chrisey, D.B.

    2007-01-01

    Roč. 59, - (2007), s. 144-149 ISSN 1742-6588 R&D Projects: GA AV ČR IAA1010110 Grant - others:CTU(CZ) 6640770030; CERES(RO) 4-178/15.11.2004 Institutional research plan: CEZ:AV0Z10100522; CEZ:AV0Z40500505 Keywords : pulluan * thin films * MAPLE Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. The use of a hydrogel matrix for controlled delivery of niacin to the gastrointestinal tract for treatment of hyperlipidemia

    Czech Academy of Sciences Publication Activity Database

    Širc, Jakub; Hrib, Jakub; Vetrík, Miroslav; Hobzová, Radka; Žák, A.; Staňková, B.; Slanař, O.; Hromádka, R.; Sandrikova, V.; Michálek, Jiří

    2015-01-01

    Roč. 64, Suppl. 1 (2015), S51-S60 ISSN 0862-8408 R&D Projects: GA MPO(CZ) FR-TI4/638; GA MŠk(CZ) EE2.3.30.0029; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:61389013 Keywords : niacin * hyperlipidemia * hydrogel Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.643, year: 2015 http://www.biomed.cas.cz/physiolres/pdf/64%20Suppl%201/64_S51.pdf

  1. [Modern polymers in matrix tablets technology].

    Science.gov (United States)

    Zimmer, Łukasz; Kasperek, Regina; Poleszak, Ewa

    2014-01-01

    Matrix tablets are the most popular method of oral drug administration, and polymeric materials have been used broadly in matrix formulations to modify and modulate drug release rate. The main goal of the system is to extend drug release profiles to maintain a constant in vivo plasma drug concentration and a consistent pharmacological effect. Polymeric matrix tablets offer a great potential as oral controlled drug delivery systems. Cellulose derivatives, like hydroxypropyl methylcellulose (HPMC) are often used as matrix formers. However, also other types of polymers can be used for this purpose including: Kollidon SR, acrylic acid polymers such as Eudragits and Carbopols. Nevertheless, polymers of natural origin like: carragens, chitosan and alginates widely used in the food and cosmetics industry are now coming to the fore of pharmaceutical research and are used in matrix tablets technology. Modern polymers allow to obtain matrix tablets by 3D printing, which enables to develop new formulation types. In this paper, the polymers used in matrix tablets technology and examples of their applications were described.

  2. General beam position controlling method for 3D optical systems based on the method of solving ray matrix equations

    Science.gov (United States)

    Chen, Meixiong; Yuan, Jie; Long, Xingwu; Kang, Zhenglong; Wang, Zhiguo; Li, Yingying

    2013-12-01

    A general beam position controlling method for 3D optical systems based on the method of solving ray matrix equations has been proposed in this paper. As a typical 3D optical system, nonplanar ring resonator of Zero-Lock Laser Gyroscopes has been chosen as an example to show its application. The total mismatching error induced by Faraday-wedge in nonplanar ring resonator has been defined and eliminated quite accurately with the error less than 1 μm. Compared with the method proposed in Ref. [14], the precision of the beam position controlling has been improved by two orders of magnitude. The novel method can be used to implement automatic beam position controlling in 3D optical systems with servo circuit. All those results have been confirmed by related alignment experiments. The results in this paper are important for beam controlling, ray tracing, cavity design and alignment in 3D optical systems.

  3. Precise laser poration to control drug delivery into and through human nail.

    Science.gov (United States)

    Vanstone, Simon; Cordery, Sarah F; Stone, James M; Gordeev, Sergey N; Guy, Richard H

    2017-12-28

    Drug treatment of diseases of the human nail remains a difficult challenge; topical therapy, in particular, is limited by very poor transport of active agents across the nail itself. The objective of this research was to examine the potential of controlled, and fibre-optic delivered, femtosecond laser light pulses to provide new pathways and opportunities for drug access to targets within and beneath the nail plate. Optical, confocal fluorescence and scanning electron microscopies demonstrated partial and complete laser poration of human nail samples, with the energy per pore and the exposure duration being the key modulating parameters that determined the extent of ablation achieved. Parallel measurements of the penetration of a model drug across laser-treated nails showed that complete poration resulted in essentially complete circumvention of the diffusion barrier, an array of 100 pores in 0.2cm 2 area of nail permitting a 10 3 -fold increase in initial drug uptake. Partial ablation of the nail created pores that extended to a range of depths; the nail material adjacent to the ablated area was rendered porous in appearance presumably due to local thermal perturbation of the nail structure. These openings offer, as a result, potential sites in which topical drug formulations might be sequestered post-poration and from which slow, sustained delivery of the active agent into and through the nail may be envisaged. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Synthesis and characterization of polymer-coated manganese ferrite nanoparticles as controlled drug delivery

    Science.gov (United States)

    Wang, Guangshuo; Zhao, Dexing; Ma, Yingying; Zhang, Zhixiao; Che, Hongwei; Mu, Jingbo; Zhang, Xiaoliang; Zhang, Zheng

    2018-01-01

    In this study, monodisperse and superparamagnetic manganese ferrite (MnFe2O4) nanoparticles have been synthesized by a one-pot sonochemical method using polyvinylpyrrolidone (PVP) as stabilizer. The as-prepared MnFe2O4 nanoparticles were investigated systematically by TEM, XRD, FTIR, XPS, SQUID and MTT. The TEM observation showed that the PVP-coated MnFe2O4 nanoparticles had uniform dispersion with narrow particle size distribution. The magnetization curves demonstrated superparamagnetic properties of the coated MnFe2O4 nanoparticles with good hydrophilicity at room temperature. The in vitro cytotoxicity experiments exhibited negligible cytotoxicity of the obtained PVP-coated MnFe2O4 nanoparticles even at the high concentration of 150 μg/mL after 24 h treatment. More importantly, anti-cancer model drug of doxorubicin hydrochloride (DOX) was loaded on the surface of MnFe2O4 nanoparticles. The drug loading capacity of the developed nanocarrier reached 0.45 mg/mg and the loaded DOX exhibited interesting pH-dependent release behavior. In conclusion, the as-prepared PVP-coated MnFe2O4 nanoparticles were proposed as a potential candidate for controlled drug delivery.

  5. Development of radioactive standards in epoxy matrix for the control of quality of activimeters

    International Nuclear Information System (INIS)

    Fragoso, Maria da Conceicao de Farias; Monteiro, Luciane Carollyne de Oliveira Reis; Oliveira, Marcia Liane de

    2016-01-01

    In the present study, a new approach for development of the standards for positron emitting radionuclides in epoxy matrix is presented. Different formulations were prepared using epoxy resin (bisphenol A diglycidyl ether - DGEBA) and curing agents, to immobilize the radioactive material. The efficiency curve and standard sample methods were applied for activity determination of a long-lived positron emitter ( 22 Na). Satisfactory results were obtained in the 3 rd combination. Thus, these radioactive standards can be used to evaluate the metrological behavior of the systems used for the measurement of the radiopharmaceuticals (activimeters) in the production centers and in nuclear medicine services. (author)

  6. Candidate gene analysis of spontaneous preterm delivery: New insights from re-analysis of a case-control study using case-parent triads and control-mother dyads

    Directory of Open Access Journals (Sweden)

    Myking Solveig

    2011-12-01

    Full Text Available Abstract Background Spontaneous preterm delivery (PTD has a multifactorial etiology with evidence of a genetic contribution to its pathogenesis. A number of candidate gene case-control studies have been performed on spontaneous PTD, but the results have been inconsistent, and do not fully assess the role of how two genotypes can impact outcome. To elucidate this latter point we re-analyzed data from a previously published case-control candidate gene study, using a case-parent triad design and a hybrid design combining case-parent triads and control-mother dyads. These methods offer a robust approach to genetic association studies for PTD compared to traditional case-control designs. Methods The study participants were obtained from the Norwegian Mother and Child Cohort Study (MoBa. A total of 196 case triads and 211 control dyads were selected for the analysis. A case-parent triad design as well as a hybrid design was used to analyze 1,326 SNPs from 159 candidate genes. We compared our results to those from a previous case-control study on the same samples. Haplotypes were analyzed using a sliding window of three SNPs and a pathway analysis was performed to gain biological insight into the pathophysiology of preterm delivery. Results The most consistent significant fetal gene across all analyses was COL5A2. The functionally similar COL5A1 was significant when combining fetal and maternal genotypes. PON1 was significant with analytical approaches for single locus association of fetal genes alone, but was possibly confounded by maternal effects. Focal adhesion (hsa04510, Cell Communication (hsa01430 and ECM receptor interaction (hsa04512 were the most constant significant pathways. Conclusion This study suggests a fetal association of COL5A2 and a combined fetal-maternal association of COL5A1 with spontaneous PTD. In addition, the pathway analysis implied interactions of genes affecting cell communication and extracellular matrix.

  7. Graphene oxide stabilized by PLA-PEG copolymers for the controlled delivery of paclitaxel.

    Science.gov (United States)

    Angelopoulou, A; Voulgari, E; Diamanti, E K; Gournis, D; Avgoustakis, K

    2015-06-01

    -loaded composites exhibited cytotoxicity against A549 cancer cells which increased with incubation time, in conjunction with the increasing with time uptake of composites by the cancer cells. Graphene oxide aqueous dispersions were effectively stabilized by water-dispersible, biocompatible and biodegradable PLA-PEG copolymers. The graphene oxide/PLA-PEG composites exhibited satisfactory paclitaxel loading capacity and sustained in vitro drug release. The paclitaxel-loaded composites could enter the A549 cancer cells and exert cytotoxicity. The results justify further investigation of the suitability of PLA-PEG stabilized graphene oxide for the controlled delivery of paclitaxel. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Precise control of the drug kinetics by means of non-invasive magnetic drug delivery system

    International Nuclear Information System (INIS)

    Chuzawa, M.; Mishima, F.; Akiyama, Y.; Nishijima, S.

    2013-01-01

    Highlights: ► We examined the kinetics of ferromagnetic drugs by simulation. ► We tried to accumulate the magnetic drug in the target part by rotating a magnet. ► Ferromagnetic drugs were accumulated in the target part along the rotating axis. ► Ferromagnetic drugs could be swept downstream in the off-axis part. -- Abstract: In order to solve the problems of the side effects and medical lowering, has been advanced a study on the drug delivery system (DDS) to accumulate the drugs locally in the body with minimum dosage. The DDS is a system that controls the drug kinetics in the body precisely and accumulates the drug locally at the target part, keeping the drugs at high density. Among the DDS, the magnetic drug delivery system (MDDS) is the one that we studied. This is a technique to accumulate drugs by using the magnetic force as the physical driving force. Our previous researches showed the possibility of the technique of MDDS to accumulate the drugs with higher accumulation rate and locality than the traditional methods. It is necessary to apply a strong external magnetic field and a high magnetic gradient to accumulate the ferromagnetic drugs at a deep diseased part non-invasively. However, by applying a static magnetic field from one direction, the drug accumulates only at the surface of the body locates near the magnet. In this study, we tried to change the magnetic field applied by a superconducting bulk magnet with time, in order to make a constant and strong magnetic field applied in the center of the body and to accumulate the ferromagnetic drugs at the deep target part in the body. First of all, the effect of the surface treatment of the ferromagnetic drugs to prevent its absorption in the normal tissue was examined. Then, to increase the accumulation rate of the ferromagnetic drugs at the target part, the distribution of magnetic field was changed, and the optimum spatial and temporal conditions of magnetic field were examined

  9. Surgical staples compared with subcuticular suture for skin closure after cesarean delivery: a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Sahar Assadi

    2016-03-01

    Full Text Available Background: Cesarean delivery is the most common surgical procedure and this prevalence is on the rise. Given these trends, cesarean wound complications, such as disruption or infection, remain an important cause of post-cesarean morbidity. Methods: We conducted a single-center randomized controlled trial that included women with viable pregnancies (≥24 weeks undergoing cesarean delivery at Motahary University Hospital, Urmia, Iran from April to November 2014. All cesarean types were included: scheduled or unscheduled and primary or repeat cesareans. Women were excluded for the following reasons: inability to obtain informed consent, immune compromising disease (e.g. AIDS, chronic steroid use, diabetic mellitus and BMI≥30. Of 266 women, 133 were randomized to staples and 133 women to suture group. Results: The mean±SD age of the staples group was 27.6±5.4 years and mean±SD age of suture was 28.7±5.9 years. Multiparity is the most frequent in both groups that by using Chi-square test, no significant differences were observed between the two groups (P=0.393. The most frequent indication for cesarean section in both groups was history of cesarean section in staple 40 cases (30.1% and suture 32 cases (24.1%. The survey was conducted using the Chi-square test was not significant (P=0.381. Pain at 6 weeks postoperatively was significantly less in the staple group (P=0.001. Operative time was longer with suture closure (4.68±0.67 versus 1.03±0.07 minute, P<0.001. The Vancouver scale score was significantly less in suture closure (6.6±0.8 versus 7.5±0.9, P=0.001. Wound disruption was significantly less in suture closure (3.8% versus 11.3%, P=0.017. Conclusion: The staple group had low pain and operation time but had a significant wound disruption and scar. The patients who have suffered a significant wound disruption were affected by age (P=0.022 and BMI (P=0.001 at compared those who were not affected by factors such as age or high BMI as

  10. Postplacental insertion of the levonorgestrel intrauterine device after cesarean delivery vs. delayed insertion: a randomized controlled trial.

    Science.gov (United States)

    Whitaker, Amy K; Endres, Loraine K; Mistretta, Stephanie Q; Gilliam, Melissa L

    2014-06-01

    This trial was designed to compare levonorgestrel intrauterine device (LNG-IUD) use at 1 year after delivery between women randomized to postplacental insertion at the time of cesarean delivery and delayed insertion 4-8 weeks after delivery. This randomized controlled trial was conducted at two urban medical centers. Eligible pregnant women with planned cesarean deliveries were randomized to immediate postplacental insertion during cesarean or delayed insertion after 4-8 weeks. We used intention-to-treat analysis for the primary outcome of LNG-IUD use 12 months after delivery. Forty-two women were randomized, 20 into the postplacental group and 22 in the delayed group. Although confirmed use of the LNG-IUD 12 months after delivery was higher in the postplacental group (60.0% vs. 40.9%, p=.35), this difference was not statistically significance. Expulsion was significantly more common in the postplacental group (20.0% vs. 0%, p=.04). There were significant differences between the two sites in baseline population characteristics, follow-up and expulsion. The trial did not answer the intended question as it was halted early due to slow enrollment. Our results show higher expulsion after postplacental insertion compared to delayed insertion but suggest similar IUD use at 12 months. Moreover, it provides valuable lessons regarding a randomized controlled trial of postplacental LNG-IUD placement due to the challenges of estimating effect size and the nature of the population who might benefit from immediate insertion. Postplacental insertion of an IUD may improve use of highly effective contraception during the postpartum period. While our results suggest higher expulsion after postplacental insertion compared to delayed insertion and similar IUD use at 12 months, our trial was insufficient to definitively test our hypothesis. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. Timing of administration of epidural analgesia and risk of operative delivery in nulliparous women: A case–control randomised study

    Directory of Open Access Journals (Sweden)

    Ipsita Chattopadhyay

    2018-01-01

    Full Text Available >Background and Aim: Epidural analgesia (EA offers an effective form of labour analgesia. The time of administration of EA and its relationship with the mode of delivery is controversial. Our study tried to assess whether early initiation of epidural analgesia influences the obstetric outcome in nulliparous women.Materials and Methods: This was a case control, randomised study which included 60 parturients in spontaneous labour divided into two equal groups, the cases and controls. Cases received EA with 10 mL of 0.125% injection bupivacaine, whereas the control group received a systemic opioid (injection pethidine 100 mg intramuscularly for pain relief. Cases were further divided into parturients receiving EA at a cervical dilatation of 3 cm or less classified as the early epidural group and those receiving EA at 4 cm or more classified as the late epidural group. The modes of delivery for the study population were recorded. Data analysis was done using Wilcoxon two-sample test. P < 0.05 was considered statistically significant.Results: The rate of instrumental vaginal delivery between the early epidural group [95% confidence interval (CI 0.358–10.821; P = 0.43] and late epidural group (95% CI 0.150–6.055; P = 0.96 was not significantly different. The cesarean-delivery rate was also not significantly different between those receiving early EA (P = 0.95 and late EA (P = 0.58 when compared with control group.Conclusion: This study showed no significant difference in the incidence of caesarean or instrumental delivery for women receiving early epidural analgesia when compared with late epidurals or no EA.

  12. Co-delivery of micronized urinary bladder matrix damps regenerative capacity of minced muscle grafts in the treatment of volumetric muscle loss injuries.

    Directory of Open Access Journals (Sweden)

    Stephen M Goldman

    Full Text Available Minced muscle grafts (MG promote de novo muscle fiber regeneration and neuromuscular strength recovery in small and large animal models of volumetric muscle loss. The most noteworthy limitation of this approach is its reliance on a finite supply of donor tissue. To address this shortcoming, this study sought to evaluate micronized acellular urinary bladder matrix (UBM as a scaffolding to promote in vivo expansion of this MG therapy in a rat model. Rats received volumetric muscle loss injuries to the tibialis anterior muscle of their left hind limb which were either left untreated or repaired with minced muscle graft at dosages of 50% and 100% of the defect mass, urinary bladder matrix in isolation, or a with an expansion product consisting of a combination of the two putative therapies in which the minced graft is delivered at a dosage of 50% of the defect mass. Rats survived to 2 and 8 weeks post injury before functional (in vivo neuromuscular strength, histological, morphological, and biochemical analyses were performed. Rats treated with the expansion product exhibited improved neuromuscular function relative to untreated VML after an 8 week time period following injury. This improvement in functional capacity, however, was accompanied with a concomitant reduction in graft mediated regeneration, as evidenced cell lineage tracing enable by a transgenic GFP expressing donor, and a mixed histological outcome indicating coincident fibrous matrix deposition with interspersed islands of nascent muscle fibers. Furthermore, quantitative immunofluorescence and transcriptional analysis following the 2 week time point suggests an exacerbated immune response to the UBM as a possible nidus for the observed suboptimal regenerative outcome. Moving forward, efforts related to the development of a MG expansion product should carefully consider the effects of the host immune response to candidate biomaterials in order to avoid undesirable dysregulation of pro

  13. Designing Novel Smart Hydrogel Formulations for the Controlled Delivery of Ocular Therapies in Contact Lens Devices

    OpenAIRE

    Phelan, David

    2015-01-01

    The major challenge to ocular drug delivery is poor bio-availability of the delivered drug, due to the anatomy of the eye. This work presents an approach to address this problem, using novel contact lens drug delivery vehicles. Antihistamines were used as a model drug due to their physical properties and molecular weight. 15% of the world’s population suffer from allergic reactions confirming antihistamines as a relevant ocular pharmaceutical. A novel pilot scale wet cast moulding proce...

  14. Temperature-Controlled Delivery of Radiofrequency Energy in Fecal Incontinence: A Randomized Sham-Controlled Clinical Trial.

    Science.gov (United States)

    Visscher, Arjan P; Lam, Tze J; Meurs-Szojda, Maria M; Felt-Bersma, Richelle J F

    2017-08-01

    Controlled delivery of radiofrequency energy has been suggested as treatment for fecal incontinence. The aim of this study was to determine whether the clinical response to the radiofrequency energy procedure is superior to sham in patients with fecal incontinence. This was a randomized sham-controlled clinical trial from 2008 to 2015. This study was conducted in an outpatient clinic. Forty patients with fecal incontinence in whom maximal conservative management had failed were randomly assigned to receiving either radiofrequency energy or sham procedure. Fecal incontinence was measured using the Vaizey incontinence score (range, 0-24). The impact of fecal incontinence on quality of life was measured by using the fecal incontinence quality-of-life score (range, 1-4). Measurements were performed at baseline and at 6 months. Anorectal function was evaluated using anal manometry and anorectal endosonography at baseline and at 3 months. At baseline, Vaizey incontinence score was 16.8 (SD 2.9). At t = 6 months, the radiofrequency energy group improved by 2.5 points on the Vaizey incontinence score compared with the sham group (13.2 (SD 3.1), 15.6 (SD 3.3), p = 0.02). The fecal incontinence quality-of-life score at t = 6 months was not statistically different. Anorectal function did not show any alteration. Patients with severe fecal incontinence were included in the study, thus making it difficult to generalize the results. Both radiofrequency energy and sham procedure improved the fecal incontinence score, the radiofrequency energy procedure more than sham. Although statistically significant, the clinical impact for most of the patients was negligible. Therefore, the radiofrequency energy procedure should not be recommended for patients with fecal incontinence until patient-related factors associated with treatment success are known. See Video Abstract at http://links.lww.com/DCR/A373.

  15. Naringenin-loaded solid lipid nanoparticles: preparation, controlled delivery, cellular uptake, and pulmonary pharmacokinetics

    Directory of Open Access Journals (Sweden)

    Ji P

    2016-03-01

    Full Text Available Peng Ji, Tong Yu, Ying Liu, Jie Jiang, Jie Xu, Ying Zhao, Yanna Hao, Yang Qiu, Wenming Zhao, Chao WuCollege of Pharmacy, Liaoning Medical University, Jinzhou, Liaoning Province, People’s Republic of ChinaAbstract: Naringenin (NRG, a flavonoid compound, had been reported to exhibit extensive pharmacological effects, but its water solubility and oral bioavailability are only ~46±6 µg/mL and 5.8%, respectively. The purpose of this study is to design and develop NRG-loaded solid lipid nanoparticles (NRG-SLNs to provide prolonged and sustained drug release, with improved stability, involving nontoxic nanocarriers, and increase the bioavailability by means of pulmonary administration. Initially, a group contribution method was used to screen the best solid lipid matrix for the preparation of SLNs. NRG-SLNs were prepared by an emulsification and low-temperature solidification method and optimized using an orthogonal experiment approach. The morphology was examined by transmission electron microscopy, and the particle size and zeta potential were determined by photon correlation spectroscopy. The total drug content of NRG-SLNs was measured by high-performance liquid chromatography, and the encapsulation efficiency (EE was determined by Sephadex gel-50 chromatography and high-performance liquid chromatography. The in vitro NRG release studies were carried out using a dialysis bag. The best cryoprotectant to prepare NRG-SLN lyophilized powder for future structural characterization was selected using differential scanning calorimetry, powder X-ray diffraction, and Fourier transform infrared spectroscopy. The short-term stability, 3-(4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT assay, cellular uptake, and pharmacokinetics in rats were studied after pulmonary administration of NRG-SLN lyophilized powder. Glycerol monostearate was selected to prepare SLNs, and the optimal formulation of NRG-SLNs was spherical in shape, with a particle

  16. La matriz OVAR. Herramienta para la implementación y el control estratégico. // The ovar matrix. Tool for the implementation and the strategic control.

    Directory of Open Access Journals (Sweden)

    M. E. Albert Díaz

    2006-01-01

    Full Text Available En este artículo se presenta a la matriz OVAR como una herramienta de control de gestión táctica operativa, quecombinada con el Cuadro de Mando Integral (CMI contribuye a la implementación y control de las estrategias, y a laintegración del sistema de decisiones estratégicas, tácticas y operativas y propiciando la participación real del hombre en elproceso de toma de decisiones.Palabras claves: Control de gestión.________________________________________________________________________________AbstractIn this article the matrix OVAR is presented as a control tool of operative tactical administration, that combined with theBalanced Scorecard contributes to the implementation and control of strategies, and to the integration of strategic system,tactical and operative decisions and propitiating the man's real participation in the process of taking decisions.Key words: Management Control.

  17. Effects of pore forming agents on chitosan-graft-poly(N-vinylpyrrolidone) hydrogel properties for use as a matrix for floating drug delivery

    Science.gov (United States)

    Budianto, E.; Al-Shidqi, M. F.; Cahyana, A. H.

    2017-07-01

    Eradicating H. pylori-based infection by using conventional oral dosage form of amoxicillin trihydrate finds difficulties to overcome rapid gastric retention time. Encapsulating amoxicillin trihydrate in floating drug delivery system may solve the problem. In this research, the floating drug delivery system of amoxicillin trihydrate encapsulated in floating chitosan-graft-poly(N-vinyl pyrrolidone) hydrogels containing CaCO3 and NaHCO3 as pore forming agents has been successfully prepared. Pore forming agents used was varied with the ratio of 10 to 25% pore forming agents to total mass of the used materials. The hydrogel were characterizedusing FTIR spectrophotometer and stereo microscope. As pore forming agents compositions increased, the porosity (%) and floating properties increased but followed by decrease in drug entrapment efficiency. Most of the floating hydrogels possessed floating ability longer than 180 min and the highest porosity was found in hydrogel containing 25% NaHCO3. Hydrogel containing CaCO3 showed sustained drug release profile than hydrogel containing NaHCO3. However, the optimum formulation was achieved at composition of 10% NaHCO3 with 57% of drug entrapped within the hydrogel and 43% drug released. The results of these studies show that NaHCO3 is an effective pore forming agents for chitosan-graft-poly(N-vinyl pyrrolidone) hydrogel preparation as compare to CaCO3.

  18. Defining the Ail Ligand-Binding Surface: Hydrophobic Residues in Two Extracellular Loops Mediate Cell and Extracellular Matrix Binding To Facilitate Yop Delivery.

    Science.gov (United States)

    Tsang, Tiffany M; Wiese, Jeffrey S; Alhabeil, Jamal A; Usselman, Lisa D; Thomson, Joshua J; Matti, Rafla; Kronshage, Malte; Maricic, Natalie; Williams, Shanedah; Sleiman, Naama H; Felek, Suleyman; Krukonis, Eric S

    2017-04-01

    Yersinia pestis , the causative agent of plague, binds host cells to deliver cytotoxic Yop proteins into the cytoplasm that prevent phagocytosis and generation of proinflammatory cytokines. Ail is an eight-stranded β-barrel outer membrane protein with four extracellular loops that mediates cell binding and resistance to human serum. Following the deletion of each of the four extracellular loops that potentially interact with host cells, the Ail-Δloop 2 and Ail-Δloop 3 mutant proteins had no cell-binding activity while Ail-Δloop 4 maintained cell binding (the Ail-Δloop 1 protein was unstable). Using the codon mutagenesis scheme SWIM (selection without isolation of mutants), we identified individual residues in loops 1, 2, and 3 that contribute to host cell binding. While several residues contributed to the binding of host cells and purified fibronectin and laminin, as well as Yop delivery, three mutations, F80A (loop 2), S128A (loop 3), and F130A (loop 3), produced particularly severe defects in cell binding. Combining these mutations led to an even greater reduction in cell binding and severely impaired Yop delivery with only a slight defect in serum resistance. These findings demonstrate that Y. pestis Ail uses multiple extracellular loops to interact with substrates important for adhesion via polyvalent hydrophobic interactions. Copyright © 2017 American Society for Microbiology.

  19. A case-control study of risk factors for surgical site infection after cesarean delivery in eastern Burkina Faso.

    Science.gov (United States)

    Kaboré, Boezemwendé; Soudouem, Georges; Seck, Ibrahima; Millogo, Tieba; Evariste Yaméogo, Wambi Maurice; Kouanda, Seni

    2016-11-01

    To identify the risk factors for surgical site infection after cesarean delivery in a rural area in eastern Burkina Faso. A matched case-control study was conducted in Fada N'Gourma Regional Hospital Center and the Diapaga Medical Center with Surgical Antenna using data from 2011-2014. A total of 99 cases of surgical site infection after cesarean delivery were included in the study. Each case was matched with a control patient similar for age, admission date, and facility where the cesarean took place. Risk factors were identified using conditional logistic regression. Multivariate analysis identified hyperthermia at admission (OR 2.37; P=0.035), the presence of caput succedaneum in newborns (OR 7.07; P=0.001), and difficult delivery (OR 3.69; P=0. 019) as risk factors for surgical site infection. Provision of quality prenatal care, use of the partograph during labor, and the responsiveness of health workers during labor can reduce surgical site infection after cesarean delivery. Copyright © 2016. Published by Elsevier Ireland Ltd.

  20. Spatiotemporal expression control correlates with intragenic scaffold matrix attachment regions (S/MARs in Arabidopsis thaliana.

    Directory of Open Access Journals (Sweden)

    Igor V Tetko

    2006-03-01

    Full Text Available Scaffold/matrix attachment regions (S/MARs are essential for structural organization of the chromatin within the nucleus and serve as anchors of chromatin loop domains. A significant fraction of genes in Arabidopsis thaliana contains intragenic S/MAR elements and a significant correlation of S/MAR presence and overall expression strength has been demonstrated. In this study, we undertook a genome scale analysis of expression level and spatiotemporal expression differences in correlation with the presence or absence of genic S/MAR elements. We demonstrate that genes containing intragenic S/MARs are prone to pronounced spatiotemporal expression regulation. This characteristic is found to be even more pronounced for transcription factor genes. Our observations illustrate the importance of S/MARs in transcriptional regulation and the role of chromatin structural characteristics for gene regulation. Our findings open new perspectives for the understanding of tissue- and organ-specific regulation of gene expression.

  1. Control of nucleation and crystal growth of a silicate apatitic phase in a glassy matrix

    International Nuclear Information System (INIS)

    Ligny, D.; Caurant, D.; Bardez, I.; Dussossoy, J.L.; Loiseau, P.; Neuville, D.R.

    2004-01-01

    Nucleation and growth of crystal in an oxide glass was studied in a Si B Al Zr Nd Ca Na O system. The nucleation and growth process were monitored by thermal analysis and isothermal experiments. The effect of the network modifier was studied. Therefore for a Ca rich sample the crystallization is homogeneous in the bulk showing a slow increase of crystallinity as temperature increases. On the other hand, a Na rich sample undergoes several crystallization processes in the bulk or from the surface, leading to bigger crystals. The activation energy of the viscous flow and the glass transition are of same magnitude when that of crystallization is a lot smaller. Early diffusion of element is done with a mechanism different than the configurational rearrangements of the liquid sate. The global density and small size of the crystals within the Ca rich matrix confirmed that it would be a profitable waste form for minor actinides. (authors)

  2. Controlled shielding and deshielding of gene delivery polyplexes using hydroxyethyl starch (HES) and alpha-amylase.

    Science.gov (United States)

    Noga, Matthäus; Edinger, Daniel; Rödl, Wolfgang; Wagner, Ernst; Winter, Gerhard; Besheer, Ahmed

    2012-04-10

    The non-viral delivery of nucleic acids faces many extracellular and intracellular hurdles on the way from injection site to the site of action. Among these, aggregation in the blood stream and rapid elimination by the mononuclear phagocytic system (MPS) represent strong obstacles towards successful development of these promising therapeutic modalities. Even the state-of-the-art solutions using PEGylation show low transfection efficiency due to limited uptake and hindered endosomal escape. Engineering the carriers with sheddable coats reduces aggregation and phagocytosis due to the effective shielding, while the controlled deshielding at the desired site of action enhances the uptake and intracellular release. This work reports for the first time the use of hydroxyethyl starch (HES) for the controlled shielding/deshielding of polyplexes. HES, with different molar masses, was grafted to polyethylenimine (PEI) and characterized using (1)H NMR, colorimetric copper-assay, and SEC. HES-PEI conjugates were used to generate polyplexes with the luciferase-expressing plasmid DNA pCMVluc, and were characterized by DLS and zeta potential measurements. Deshielding was tested in vitro by zeta potential measurements and, erythrocyte aggregation assay upon addition of α-amylase (AA) to the HES-decorated particles. The addition of AA led to gradual increase in the zeta potential of the nanoparticles over 0.5 to 1h and to a higher aggregation tendency for erythrocytes due to the degradation of the HES-coat and exposure of the polyplexes' positive charge. In vitro transfection experiments were conducted in 2 cell-lines±AA in the culture medium. The amylase-treated HES-decorated complexes showed up to 2 orders of magnitude higher transfection levels compared to the untreated HES-shielded particles, while AA had no effect on the transfection of PEG-coated or uncoated polyplexes. Finally, flow cytometry showed that the addition of AA increased the amount of delivered DNA per cell for

  3. Influence of different structured channels of mesoporous silicate on the controlled ibuprofen delivery

    International Nuclear Information System (INIS)

    Gao, Lin; Sun, Jihong; Zhang, Li; Wang, Jinpeng; Ren, Bo

    2012-01-01

    The bimodal mesoporous silicas with short random mesoporous channels and MCM-41 with long ordered mesopores were synthesised and modified with 3-(2-aminoethylamino) propyltrimethoxysilane as ibuprofen carriers to study the influence of mesoporous structure on drug delivery property. For further comparing the different mesoporous channels, modified SBA-15 with relative large and long ordered mesopores was also synthesized as drug carriers. The resultant samples were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, N 2 adsorption–desorption isotherms, thermogravimetric analyses, solid-state 29 Si NMR spectra, elemental analysis, and UV–vis spectra. Meanwhile, the Korsmeyer–Peppas equation f t = kt n was employed to analyze the drug release profile and three release mediums including simulated fluid solution, distilled water and simulated gastric fluid were used. The results indicated that the modified BMMs with the bimodal mesopores leaded to the most drug loading amount of 25.0 mg/0.1 g, while the MCM-41 with the long and one-dimensional mesopores had the least loading amount around 20.3 mg/0.1 g. Meanwhile, the easier diffusion behavior of drug molecules in the bimodal mesopore channels of BMMs resulted in relatively faster drug release properties in comparison with MCM-41, while the release time maintained in SBF for about 12 h (release percent was about 90 wt%) and corresponding release constant k obtained from Korsmeyer–Peppas equation was around 4.10. Highlights: ► BMMs, MCM-41 and SBA-15 with different mesostructure channels were modified with amino groups via post-treatment procedure. ► Loading and release profiles of ibuprofen in modified BMMs, MCM-41 and SBA-15. ► BMMs presents more drug loading amount than MCM-41 as well as better controlled release than SBA-15.

  4. Delivery of tidal volume from four anaesthesia ventilators during volume-controlled ventilation: a bench study.

    Science.gov (United States)

    Wallon, G; Bonnet, A; Guérin, C

    2013-06-01

    Tidal volume (V(T)) must be accurately delivered by anaesthesia ventilators in the volume-controlled ventilation mode in order for lung protective ventilation to be effective. However, the impact of fresh gas flow (FGF) and lung mechanics on delivery of V(T) by the newest anaesthesia ventilators has not been reported. We measured delivered V(T) (V(TI)) from four anaesthesia ventilators (Aisys™, Flow-i™, Primus™, and Zeus™) on a pneumatic test lung set with three combinations of lung compliance (C, ml cm H2O(-1)) and resistance (R, cm H2O litre(-1) s(-2)): C60R5, C30R5, C60R20. For each CR, three FGF rates (0.5, 3, 10 litre min(-1)) were investigated at three set V(T)s (300, 500, 800 ml) and two values of PEEP (0 and 10 cm H2O). The volume error = [(V(TI) - V(Tset))/V(Tset)] ×100 was computed in body temperature and pressure-saturated conditions and compared using analysis of variance. For each CR and each set V(T), the absolute value of the volume error significantly declined from Aisys™ to Flow-i™, Zeus™, and Primus™. For C60R5, these values were 12.5% for Aisys™, 5% for Flow-i™ and Zeus™, and 0% for Primus™. With an increase in FGF, absolute values of the volume error increased only for Aisys™ and Zeus™. However, in C30R5, the volume error was minimal at mid-FGF for Aisys™. The results were similar at PEEP 10 cm H2O. Under experimental conditions, the volume error differed significantly between the four new anaesthesia ventilators tested and was influenced by FGF, although this effect may not be clinically relevant.

  5. The effect of targeting scheme on tidal volume delivery during volume control mechanical ventilation.

    Science.gov (United States)

    Volsko, Teresa A; Hoffman, Justin; Conger, Alecia; Chatburn, Robert L

    2012-08-01

    Technological advances have increased ventilator mode complexity and risk of operator error. To compare differences in volume control (VC) ventilation with set-point and dual targeting. Two hypotheses were tested: tidal volume (V(T)) delivery is different with VC using set-point versus dual targeting during active versus passive breathing; VC with dual targeting delivers V(T) similar to pressure support ventilation (PS) with active breathing. The Ingmar Medical ASL 5000 lung model simulated pulmonary mechanics of an adult patient with ARDS during active and passive ventilation. Resistance was standardized at 10 cm H(2)O/L/s and compliance at 32 mL/cm H(2)O. Active breathing was simulated by setting the frequency (f) = 26 breaths/min, and adjusting the muscle pressure (P(mus)) to produce a V(T) of 384 mL. VC was initiated with the Puritan Bennett 840 (set-point targeting) and the Servo-i (dual targeting) at V(T) = 430 mL, mandatory f = 15 breaths/min, and PEEP = 10 cm H(2)O. During PS, cycle threshold was set to 30% and peak inspiratory pressure adjusted to produce a V(T) similar to that delivered during VC. Expiratory V(T) was collected on 10 consecutive breaths during active and passive breathing with VC and PS. Mean V(T) differences (active vs passive model) were compared using analysis of variance. Statistical significance was established at P targeting schemes: VC set-point = 37.3 ± 3.5 mL, VC-dual = 77.1 ± 3.3 mL, and PS = 406.1 ± 1.5 mL (P targeting during VC allows increased V(T), compared to set-point, but not as much as PS.

  6. Synthesis and characterization of pharmaceutical surfactant templated mesoporous silica: Its application to controlled delivery of duloxetine

    Energy Technology Data Exchange (ETDEWEB)

    Mani, Ganesh; Pushparaj, Hemalatha; Peng, Mei Mei; Muthiahpillai, Palanichamy [Department of Chemical Engineering, Hanseo University, Seosan-si 356 706 (Korea, Republic of); Udhumansha, Ubaidulla [Department of Chemical Engineering, Hanseo University, Seosan-si 356 706 (Korea, Republic of); Department of Pharmaceutics, C.L. Baid Metha College of Pharmacy, Chennai (India); Jang, Hyun Tae, E-mail: htjang@hanseo.ac.kr [Department of Chemical Engineering, Hanseo University, Seosan-si 356 706 (Korea, Republic of)

    2014-03-01

    Graphical abstract: - Highlights: • Usefulness of dual pharmaceutical surfactants in silica synthesis was evaluated. • Effects of concentration of secondary template (Tween-40) were studied. • Effects of fixed solvothermal condition on mesostructure formation were studied. • Duloxetine drug loading capability was studied. • Sustained release of duloxetine was evaluated. - Abstract: A new group of mesoporous silica nanoparticles (MSNs) were synthesized using combination pharmaceutical surfactants, Triton X-100 and Tween-40 as template and loaded with duloxetine hydrochloride (DX), for improving the sustained release of DX and patterns with high drug loading. Agglomerated spherical silica MSNs were synthesized by sol–gel and solvothermal methods. The calcined and drug loaded MSNs were characterized using X-ray diffraction (XRD), Braunner–Emmett–Teller (BET), thermogravimetric analysis (TGA), Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), diffuse reflectance ultraviolet–visible (DRS-UV–vis) spectroscopy. MSNs with high surface area and pore volume were selected and studied for their DX loading and release. The selected MSNs can accommodate a maximum of 34% DX within it. About 90% was released at 200 h and hence, the synthesized MSNs were capable of engulfing DX and sustain its release. Further form the Ritger and Peppas, Higuchi model for mechanism drug release from all the MSN matrices follows anomalous transport or Non-Fickian diffusion with the ‘r’ and ‘n’ value 0.9 and 0.45 < n < 1, respectively. So, from this study it could be concluded that the MSNs synthesized using pharmaceutical templates were better choice of reservoir for the controlled delivery of drug which requires sustained release.

  7. Long-Term Stability of Tramadol and Ketamine Solutions for Patient-Controlled Analgesia Delivery.

    Science.gov (United States)

    Gu, Junfeng; Qin, Wengang; Chen, Fuchao; Xia, Zhongyuan

    2015-08-26

    Subanesthetic doses of ketamine as an adjuvant to tramadol in patient-controlled analgesia (PCA) for postoperative pain have been shown to improve the quality of analgesia. However, there are no such commercially available drug mixtures, and the stability of the combination has rarely been assessed. Admixtures were assessed for periods of up to 14 days at 4°C and 25°C. Three different mixtures of tramadol and ketamine (tramadol 5.0 mg/mL + ketamine 0.5 mg/mL, tramadol 5.0 mg/mL + ketamine 1.0 mg/mL, and tramadol 5.0 mg/mL + ketamine 2.0 mg/mL) were prepared in polyolefin bags by combining these 2 drugs with 0.9% sodium chloride (normal saline [NS]). The chemical stability of the admixtures was evaluated by a validated high-performance liquid chromatography (HPLC) method and by measurement of pH values. Solution appearance and color were assessed by observing the samples against black and white backgrounds. Solutions were considered stable if they maintained 90% of the initial concentration of each drug. The percentages of initial concentration of tramadol and ketamine in the various solutions remained above 98% when stored at 4°C or 25°C over the testing period. No changes in color or turbidity were observed in any of the prepared solutions. Throughout this period, pH values remained stable. The results indicate that the drug mixtures of tramadol with ketamine in NS for PCA delivery systems were stable for 14 days when stored in polyolefin bags at 4°C or 25°C.

  8. Influence of different structured channels of mesoporous silicate on the controlled ibuprofen delivery

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Lin [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, 100 PingLeYuan, Chaoyang District, Beijing 100124 (China); Sun, Jihong, E-mail: jhsun@bjut.edu.cn [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, 100 PingLeYuan, Chaoyang District, Beijing 100124 (China); Zhang, Li; Wang, Jinpeng; Ren, Bo [Department of Chemistry and Chemical Engineering, College of Environmental and Energy Engineering, Beijing University of Technology, 100 PingLeYuan, Chaoyang District, Beijing 100124 (China)

    2012-08-15

    The bimodal mesoporous silicas with short random mesoporous channels and MCM-41 with long ordered mesopores were synthesised and modified with 3-(2-aminoethylamino) propyltrimethoxysilane as ibuprofen carriers to study the influence of mesoporous structure on drug delivery property. For further comparing the different mesoporous channels, modified SBA-15 with relative large and long ordered mesopores was also synthesized as drug carriers. The resultant samples were characterized with X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, N{sub 2} adsorption-desorption isotherms, thermogravimetric analyses, solid-state {sup 29}Si NMR spectra, elemental analysis, and UV-vis spectra. Meanwhile, the Korsmeyer-Peppas equation f{sub t} = kt{sup n} was employed to analyze the drug release profile and three release mediums including simulated fluid solution, distilled water and simulated gastric fluid were used. The results indicated that the modified BMMs with the bimodal mesopores leaded to the most drug loading amount of 25.0 mg/0.1 g, while the MCM-41 with the long and one-dimensional mesopores had the least loading amount around 20.3 mg/0.1 g. Meanwhile, the easier diffusion behavior of drug molecules in the bimodal mesopore channels of BMMs resulted in relatively faster drug release properties in comparison with MCM-41, while the release time maintained in SBF for about 12 h (release percent was about 90 wt%) and corresponding release constant k obtained from Korsmeyer-Peppas equation was around 4.10. Highlights: Black-Right-Pointing-Pointer BMMs, MCM-41 and SBA-15 with different mesostructure channels were modified with amino groups via post-treatment procedure. Black-Right-Pointing-Pointer Loading and release profiles of ibuprofen in modified BMMs, MCM-41 and SBA-15. Black-Right-Pointing-Pointer BMMs presents more drug loading amount than MCM-41 as well as better controlled release than SBA-15.

  9. Intrauterine Device Placement During Cesarean Delivery and Continued Use 6 Months Postpartum: A Randomized Controlled Trial.

    Science.gov (United States)

    Levi, Erika E; Stuart, Gretchen S; Zerden, Matthew L; Garrett, Joanne M; Bryant, Amy G

    2015-07-01

    To compare intrauterine device (IUD) use at 6 months postpartum among women who underwent intracesarean delivery (during cesarean delivery) IUD placement compared with women who planned for interval IUD placement 6 or more weeks postpartum. In this nonblinded randomized trial, women who were undergoing a cesarean delivery and desired an IUD were randomized to intracesarean delivery or interval IUD placement. The primary outcome was IUD use at 6 months postpartum. A sample size of 112 (56 in each group) was planned to detect a 15% difference in IUD use at 6 months postpartum between groups. From March 2012 to June 2014, 172 women were screened and 112 women were randomized into the trial. Baseline characteristics were similar between groups. Data regarding IUD use at 6 months postpartum were available for 98 women, 48 and 50 women in the intracesarean delivery and interval groups, respectively. A larger proportion of the women in the intracesarean delivery group were using an IUD at 6 months postpartum (40/48 [83%]) compared with those in the interval group (32/50 [64%], relative risk 1.3, 95% confidence interval 1.02-1.66). Among the 56 women randomized to interval IUD insertion, 22 (39%) of them never received an IUD; 14 (25%) never returned for IUD placement, five (9%) women declined an IUD, and three (5%) had a failed IUD placement. Intrauterine device placement at the time of cesarean delivery leads to a higher proportion of IUD use at 6 months postpartum when compared with interval IUD placement. I.

  10. Polycaprolactone diacrylate crosslinked biodegradable semi-interpenetrating networks of polyacrylamide and gelatin for controlled drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Jaiswal, Maneesh; Koul, Veena [Centre for Biomedical Engineering, Indian Institute of Technology, New Delhi 110016 (India); Dinda, Amit K [Department of Pathology, All India Institute of Medical Sciences, New Delhi 110029 (India); Gupta, Asheesh, E-mail: veenak_iitd@yahoo.co [Department of Biochemical Pharmacology, Defense Institute of Physiology and Allied Sciences, Ministry of Defense, New Delhi 110059 (India)

    2010-12-15

    A biodegradable semi-interpenetrating hydrogel network (semi-IPN) of polyacrylamide and gelatin was prepared using polycaprolactone diacrylate (mol. wt {approx} 640) as a crosslinker. The drug-polymer interaction and IPN formation were investigated by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) and thermal gravimetric analysis (TGA). Scanning electron micrographs of lyophilized matrices revealed porous internal structure with varying pore sizes under equilibrium hydrated conditions, depending upon formulation composition. pH-dependent swelling and degradation was enhanced with increasing gelatin content and decreasing crosslinker concentration (Cs). Compression modulus (CM) (at 20% strain) increased significantly from 23 {+-} 1.4 to 75 {+-} 2.7 kPa (p < 0.02) with increasing Cs (from 0.5 to 2.0 mol%), while it decreased from 162 {+-} 6.4 to 23 {+-} 1.4 kPa (p < 0.05) with decreasing PAm/G ratio. Cell viability studies by MTT assay showed excellent cytocompatibility of matrices with fibroblast L929 cells. Curcumin, a hydrophobic phytochemical, was loaded by a diffusion method and its release profile was investigated in 4% w/v aqueous BSA solution at 75 rpm (at 37 {+-} 0.2 {sup 0}C). Fitting of drug release data in the Korsmeyer-Peppas model suggested sustained release behavior up to 10 days with a combination of diffusion and erosion mechanism (0.5 < n < 1.0; M{sub t}/M{sub {infinity} {<=}} 0.6). The newly developed porous, biodegradable and elastic semi-IPNs may serve as an ideal matrix for controlled drug release and wound healing applications. The possibilities can be explored for pharmaceutical and tissue engineering applications.

  11. In vivo evaluation and in-depth pharmaceutical characterization of a rapidly dissolving solid ocular matrix for the topical delivery of timolol maleate in the rabbit eye model.

    Science.gov (United States)

    Moosa, Raeesa M; Choonara, Yahya E; du Toit, Lisa C; Tomar, Lomas K; Tyagi, Charu; Kumar, Pradeep; Carmichael, Trevor R; Pillay, Viness

    2014-05-15

    The purpose of this study was to investigate the in-depth pharmaceutical properties and in vivo behavior of a novel lyophilized rapidly dissolving solid ocular matrix (RD-SOM) as a 'solid eye drop' formulation comprising timolol maleate as the model drug. Thermal and molecular transition analysis displayed similar findings with no incompatibility between formulation components. Porositometric studies confirmed the presence of interconnecting pores across the matrix surface. The HETCAM test indicated an irritation score of 0 with the inference of good tolerability for the RD-SOM in the New Zealand White albino rabbit eye model. Ex vivo permeation across excised rabbit cornea showed an improved steady state drug flux (0.00052 mg cm(-2)min(-1)) and permeability co-efficient (1.7 × 10(-4)cmmin(-1)) for the RD-SOM compared to pure drug and a marketed eye drop preparation. UPLC analysis quantitatively separated timolol maleate and the internal standard (diclofenac sodium) and gamma irradiation was used as a terminal sterilization procedure. In vivo results revealed a peak concentration of timolol was reached at 104.9 min. In the case of a typical eye drop formulation a lower Cmax was obtained (1.97 ug/mL). Level A point-to-point IVIVC plots via the Wagner-Nelson method revealed a satisfactory R(2) value of 0.84. In addition, the biodegradability and ocular compatibility of the RD-SOM was confirmed by histopathological toxicity studies. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. CONTROLLED RELEASE MATRIX UNCOATED TABLETS OF ENALAPRIL MALEATE USING HPMC ALONE

    OpenAIRE

    Nair, Anroop B.; Vyas, Hiral; Kumar, Ashok

    2010-01-01

    Hydroxy propyl methyl cellulose (HPMC) is generally combined with hydrophobic polymers in fabricating oral controlled solid dosage forms. This study evaluated the utility of diverse grades of HPMC in developing a controlled release formulation for a hydrophilic drug, enalapril maleate. Controlled release uncoated tablets were prepared by direct compression technique. Two grades of HPMC (K100 and K4M) in different proportions were used to prepare the tablets, and were evaluated for physical pr...

  13. Dual-functional Polyurea Microcapsules for Chronic Wound Care Dressings: Sustained Drug Delivery and Non-leaching Infection Control

    Science.gov (United States)

    He, Wei

    A new design of dual-functional polyurea microcapsules was proposed for chronic wound dressings to provide both non-leaching infection control and sustained topical drug delivery functionalities. Quaternary ammonium functionalized polyurea microcapsules (MCQs) were synthesized under mild conditions through an interfacial crosslinking reaction between branched polyethylenimine (PEI) and 2,4-toluene diisocyanate (TDI) in a dimethylformamide/cyclohexane emulsion. An in-situ modification method was developed to endow non-leaching surface antimicrobial properties to MCQs via bonding antimicrobial surfactants to surface isocyanate residues on the polyurea shells. The resultant robust MCQs with both non-leaching antimicrobial properties and sustained drug releasing properties have potential applications in medical textiles, such as chronic wound dressings, for infection control and drug delivery.

  14. Enzyme controlled glucose auto-delivery for high cell density cultivations in microplates and shake flasks

    Directory of Open Access Journals (Sweden)

    Casteleijn Marco G

    2008-11-01

    Full Text Available Abstract Background Here we describe a novel cultivation method, called EnBase™, or enzyme-based-substrate-delivery, for the growth of microorganisms in millilitre and sub-millilitre scale which yields 5 to 20 times higher cell densities compared to standard methods. The novel method can be directly applied in microwell plates and shake flasks without any requirements for additional sensors or liquid supply systems. EnBase is therefore readily applicable for many high throughput applications, such as DNA production for genome sequencing, optimisation of protein expression, production of proteins for structural genomics, bioprocess development, and screening of enzyme and metagenomic libraries. Results High cell densities with EnBase are obtained by applying the concept of glucose-limited fed-batch cultivation which is commonly used in industrial processes. The major difference of the novel method is that no external glucose feed is required, but glucose is released into the growth medium by enzymatic degradation of starch. To cope with the high levels of starch necessary for high cell density cultivation, starch is supplied to the growing culture suspension by continuous diffusion from a storage gel. Our results show that the controlled enzyme-based supply of glucose allows a glucose-limited growth to high cell densities of OD600 = 20 to 30 (corresponding to 6 to 9 g l-1 cell dry weight without the external feed of additional compounds in shake flasks and 96-well plates. The final cell density can be further increased by addition of extra nitrogen during the cultivation. Production of a heterologous triosphosphate isomerase in E. coli BL21(DE3 resulted in 10 times higher volumetric product yield and a higher ratio of soluble to insoluble product when compared to the conventional production method. Conclusion The novel EnBase method is robust and simple-to-apply for high cell density cultivation in shake flasks and microwell plates. The

  15. pH-activated nanoparticles for controlled topical delivery of farnesol to disrupt oral biofilm virulence.

    Science.gov (United States)

    Horev, Benjamin; Klein, Marlise I; Hwang, Geelsu; Li, Yong; Kim, Dongyeop; Koo, Hyun; Benoit, Danielle S W

    2015-03-24

    Development of effective therapies to control oral biofilms is challenging, as topically introduced agents must avoid rapid clearance from biofilm-tooth interfaces while targeting biofilm microenvironments. Additionally, exopolysaccharides-matrix and acidification of biofilm microenvironments are associated with cariogenic (caries-producing) biofilm virulence. Thus, nanoparticle carriers capable of binding to hydroxyapatite (HA), saliva-coated HA (sHA), and exopolysaccharides with enhanced drug release at acidic pH were developed. Nanoparticles are formed from diblock copolymers composed of 2-(dimethylamino)ethyl methacrylate (DMAEMA), butyl methacrylate (BMA), and 2-propylacrylic acid (PAA) (p(DMAEMA)-b-p(DMAEMA-co-BMA-co-PAA)) that self-assemble into ∼21 nm cationic nanoparticles. Nanoparticles exhibit outstanding adsorption affinities (∼244 L-mmol(-1)) to negatively charged HA, sHA, and exopolysaccharide-coated sHA due to strong electrostatic interactions via multivalent tertiary amines of p(DMAEMA). Owing to hydrophobic cores, nanoparticles load farnesol, a hydrophobic antibacterial drug, at ∼22 wt %. Farnesol release is pH-dependent with t1/2 = 7 and 15 h for release at pH 4.5 and 7.2, as nanoparticles undergo core destabilization at acidic pH, characteristic of cariogenic biofilm microenvironments. Importantly, topical applications of farnesol-loaded nanoparticles disrupted Streptococcus mutans biofilms 4-fold more effectively than free farnesol. Mechanical stability of biofilms treated with drug-loaded nanoparticles was compromised, resulting in >2-fold enhancement in biofilm removal under shear stress compared to free farnesol and controls. Farnesol-loaded nanoparticles effectively attenuated biofilm virulence in vivo using a clinically relevant topical treatment regimen (2×/day) in a rodent dental caries disease model. Strikingly, treatment with farnesol-loaded nanoparticles reduced both the number and severity of carious lesions, while free

  16. Two-step algorithm of generalized PAPA method applied to linear programming solution of dynamic matrix control

    International Nuclear Information System (INIS)

    Shimizu, Yoshiaki

    1991-01-01

    In recent complicated nuclear systems, there are increasing demands for developing highly advanced procedures for various problems-solvings. Among them keen interests have been paid on man-machine communications to improve both safety and economy factors. Many optimization methods have been good enough to elaborate on these points. In this preliminary note, we will concern with application of linear programming (LP) for this purpose. First we will present a new superior version of the generalized PAPA method (GEPAPA) to solve LP problems. We will then examine its effectiveness when applied to derive dynamic matrix control (DMC) as the LP solution. The approach is to aim at the above goal through a quality control of process that will appear in the system. (author)

  17. Extracellular matrix control of mammary gland morphogenesis and tumorigenesis: insights from imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ghajar, Cyrus M; Bissell, Mina J

    2008-10-23

    The extracellular matrix (ECM), once thought to solely provide physical support to a tissue, is a key component of a cell's microenvironment responsible for directing cell fate and maintaining tissue specificity. It stands to reason, then, that changes in the ECM itself or in how signals from the ECM are presented to or interpreted by cells can disrupt tissue organization; the latter is a necessary step for malignant progression. In this review, we elaborate on this concept using the mammary gland as an example. We describe how the ECM directs mammary gland formation and function, and discuss how a cell's inability to interpret these signals - whether as a result of genetic insults or physicochemical alterations in the ECM - disorganizes the gland and promotes malignancy. By restoring context and forcing cells to properly interpret these native signals, aberrant behavior can be quelled and organization re-established. Traditional imaging approaches have been a key complement to the standard biochemical, molecular, and cell biology approaches used in these studies. Utilizing imaging modalities with enhanced spatial resolution in live tissues may uncover additional means by which the ECM regulates tissue structure, on different length scales, through its pericellular organization (short-scale) and by biasing morphogenic and morphostatic gradients (long-scale).

  18. Myogenic Progenitor Cells Control Extracellular Matrix Production by Fibroblasts during Skeletal Muscle Hypertrophy.

    Science.gov (United States)

    Fry, Christopher S; Kirby, Tyler J; Kosmac, Kate; McCarthy, John J; Peterson, Charlotte A

    2017-01-05

    Satellite cells, the predominant stem cell population in adult skeletal muscle, are activated in response to hypertrophic stimuli and give rise to myogenic progenitor cells (MPCs) within the extracellular matrix (ECM) that surrounds myofibers. This ECM is composed largely of collagens secreted by interstitial fibrogenic cells, which influence satellite cell activity and muscle repair during hypertrophy and aging. Here we show that MPCs interact with interstitial fibrogenic cells to ensure proper ECM deposition and optimal muscle remodeling in response to hypertrophic stimuli. MPC-dependent ECM remodeling during the first week of a growth stimulus is sufficient to ensure long-term myofiber hypertrophy. MPCs secrete exosomes containing miR-206, which represses Rrbp1, a master regulator of collagen biosynthesis, in fibrogenic cells to prevent excessive ECM deposition. These findings provide insights into how skeletal stem and progenitor cells interact with other cell types to actively regulate their extracellular environments for tissue maintenance and adaptation. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Viral Delivery of dsRNA for Control of Insect Agricultural Pests and Vectors of Human Disease: Prospects and Challenges

    Directory of Open Access Journals (Sweden)

    Anna Kolliopoulou

    2017-06-01

    Full Text Available RNAi is applied as a new and safe method for pest control in agriculture but efficiency and specificity of delivery of dsRNA trigger remains a critical issue. Various agents have been proposed to augment dsRNA delivery, such as engineered micro-organisms and synthetic nanoparticles, but the use of viruses has received relatively little attention. Here we present a critical view of the potential of the use of recombinant viruses for efficient and specific delivery of dsRNA. First of all, it requires the availability of plasmid-based reverse genetics systems for virus production, of which an overview is presented. For RNA viruses, their application seems to be straightforward since dsRNA is produced as an intermediate molecule during viral replication, but DNA viruses also have potential through the production of RNA hairpins after transcription. However, application of recombinant virus for dsRNA delivery may not be straightforward in many cases, since viruses can encode RNAi suppressors, and virus-induced silencing effects can be determined by the properties of the encoded RNAi suppressor. An alternative is virus-like particles that retain the efficiency and specificity determinants of natural virions but have encapsidated non-replicating RNA. Finally, the use of viruses raises important safety issues which need to be addressed before application can proceed.

  20. Balanced Current Control Strategy for Current Source Rectifier Stage of Indirect Matrix Converter under Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yeongsu Bak

    2016-12-01

    Full Text Available This paper proposes a balanced current control strategy for the current source rectifier (CSR stage of an indirect matrix converter (IMC under unbalanced grid voltage conditions. If the three-phase grid connected to the voltage source inverter (VSI of the IMC has unbalanced voltage conditions, it affects the currents of the CSR stage and VSI stage, and the currents are distorted. Above all, the distorted currents of the CSR stage cause instability in the overall system, which can affect the life span of the system. Therefore, in this paper, a control strategy for balanced currents in the CSR stage is proposed. To achieve balanced currents in the CSR stage, the VSI stage should receive DC power without ripple components from the CSR stage. This is implemented by controlling the currents in the VSI stage. Therefore, the proposed control strategy decouples the positive and negative phase-sequence components existing in the unbalanced voltages and currents of the VSI stage. Using the proposed control strategy under unbalanced grid voltage conditions, the stability and life span of the overall system can be improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.

  1. [The randomized controlled trial of the prison-based Japanese Matrix Program (J-MAT) for methamphetamine abusers].

    Science.gov (United States)

    Harada, Takayuki

    2012-12-01

    Methamphetamine use is subject to severe criminal punishment in Japan and approximately 22% of the prison population were confined for violations of the stimulants control law in 2009. Although the high recidivism rate is also a problem, no systematic treatment has been conducted in prison. Therefore, the development of the prison-based treatment program is necessary. In this study, the prison-based program was developed based on the Matrix Model, which is the cognitive-behavioral treatment for amphetamine users developed in the US. The program was tailored in order to address the treatment needs of the Japanese amphetamine users considering Japanese culture and the prison climate. The randomized controlled trial was conducted in order to evaluate the effectiveness the Japanese Matrix program (J-MAT). 60 prisoners were randomly assigned either to the J-MAT or the control groups and those who in the J-MAT group received the program once a week for 12 weeks. The abstinence rate could not be used as the outcome measure because the participants could not be followed after the release from prison due to the legal reasons. Therefore, the psychological variables including coping skills, self-efficacy and motivation were used as outcome measures, which are considered as the important predictive factors of abstinence. 93.3% of the J-MAT participants completed the program. The coping skills of the treated prisoners were improved significantly after treatment comparing to the control (F (1, 27) = 9.03, p < .001), however other psychological variables were not significantly improved. The results suggested the effectiveness of the J-MAT because both treatment completion and coping skills are powerful predictors of abstinence. Further study is required and in which the participants should be followed after the completion of treatment in order to compare the relapse rates between the groups and to measure the long-term treatment gain.

  2. Survey on Monitoring and Quality Controlling of the Mobile Biosignal Delivery.

    Science.gov (United States)

    Pawar, Pravin A; Edla, Damodar R; Edoh, Thierry; Shinde, Vijay; van Beijnum, Bert-Jan

    2017-10-31

    A Mobile Patient Monitoring System (MPMS) acquires patient's biosignals and transmits them using wireless network connection to the decision-making module or healthcare professional for the assessment of patient's condition. A variety of wireless network technologies such as wireless personal area networks (e.g., Bluetooth), mobile ad-hoc networks (MANET), and infrastructure-based networks (e.g., WLAN and cellular networks) are in practice for biosignals delivery. The wireless network quality-of-service (QoS) requirements of biosignals delivery are mainly specified in terms of required bandwidth, acceptable delay, and tolerable error rate. An important research challenge in the MPMS is how to satisfy QoS requirements of biosignals delivery in the environment characterized by patient mobility, deployment of multiple wireless network technologies, and variable QoS characteristics of the wireless networks. QoS requirements are mainly application specific, while available QoS is largely dependent on QoS provided by wireless network in use. QoS provisioning refers to providing support for improving QoS experience of networked applications. In resource poor conditions, application adaptation may also be required to make maximum use of available wireless network QoS. This survey paper presents a survey of recent developments in the area of QoS provisioning for MPMS. In particular, our contributions are as follows: (1) overview of wireless networks and network QoS requirements of biosignals delivery; (2) survey of wireless networks' QoS performance evaluation for the transmission of biosignals; and (3) survey of QoS provisioning mechanisms for biosignals delivery in MPMS. We also propose integrating end-to-end QoS monitoring and QoS provisioning strategies in a mobile patient monitoring system infrastructure to support optimal delivery of biosignals to the healthcare professionals.

  3. Are intrapartum and neonatal deaths in breech delivery at term potentially avoidable?--a blinded controlled audit

    DEFF Research Database (Denmark)

    Krebs, Lone; Langhoff-Roos, Jens; Bødker, Birgit

    2002-01-01

    -92 were studied. For each of the 12 deaths two controls matched by presentation and planned mode of delivery were selected. Eleven obstetricians assessed the care through narratives that ended when the infant was delivered to umbilicus and stated if the infant died, and whether the "possible death......" was potentially avoidable. The majority thought that 42% of cases and 9% of the controls had died. Antenatal and intrapartum care was suboptimal respectively in 17% and 25% of cases and 4% and 26% of controls. The assumed death was found to have been potentially avoidable in 58% of cases and 17% of controls. Care...... in pregnancies with IUGR, pre-eclampsia, placental abruption, post-maturity, the time from decision to performance of cesarean section, and compliance between patient and professionals were more often criticized in cases than in controls. Controlled audit seemed to be a valuable tool for quality improvement...

  4. CADM1 controls actin cytoskeleton assembly and regulates extracellular matrix adhesion in human mast cells.

    Directory of Open Access Journals (Sweden)

    Elena P Moiseeva

    Full Text Available CADM1 is a major receptor for the adhesion of mast cells (MCs to fibroblasts, human airway smooth muscle cells (HASMCs and neurons. It also regulates E-cadherin and alpha6beta4 integrin in other cell types. Here we investigated a role for CADM1 in MC adhesion to both cells and extracellular matrix (ECM. Downregulation of CADM1 in the human MC line HMC-1 resulted not only in reduced adhesion to HASMCs, but also reduced adhesion to their ECM. Time-course studies in the presence of EDTA to inhibit integrins demonstrated that CADM1 provided fast initial adhesion to HASMCs and assisted with slower adhesion to ECM. CADM1 downregulation, but not antibody-dependent CADM1 inhibition, reduced MC adhesion to ECM, suggesting indirect regulation of ECM adhesion. To investigate potential mechanisms, phosphotyrosine signalling and polymerisation of actin filaments, essential for integrin-mediated adhesion, were examined. Modulation of CADM1 expression positively correlated with surface KIT levels and polymerisation of cortical F-actin in HMC-1 cells. It also influenced phosphotyrosine signalling and KIT tyrosine autophosphorylation. CADM1 accounted for 46% of surface KIT levels and 31% of F-actin in HMC-1 cells. CADM1 downregulation resulted in elongation of cortical actin filaments in both HMC-1 cells and human lung MCs and increased cell rigidity of HMC-1 cells. Collectively these data suggest that CADM1 is a key adhesion receptor, which regulates MC net adhesion, both directly through CADM1-dependent adhesion, and indirectly through the regulation of other adhesion receptors. The latter is likely to occur via docking of KIT and polymerisation of cortical F-actin. Here we propose a stepwise model of adhesion with CADM1 as a driving force for net MC adhesion.

  5. Development of a Predictive Model for the Stabilizer Concentration Estimation in Microreservoir Transdermal Drug Delivery Systems Using Lipophilic Pressure-Sensitive Adhesives as Matrix/Carrier.

    Science.gov (United States)

    Chenevas-Paule, Clémence; Wolff, Hans-Michael; Ashton, Mark; Schubert, Martin; Dodou, Kalliopi

    2017-05-01

    Microreservoir-type transdermal drug delivery systems (MTDDS) can prevent drug crystallization; however, no current predictive model considers the impact of drug load and hydration on their physical stability. We investigated MTDDS films containing polyvinylpyrrolidone (PVP) as polymeric drug stabilizer in lipophilic pressure-sensitive adhesive (silicone). Medicated and unmedicated silicone films with different molar N-vinylpyrrolidone:drug ratios were prepared and characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy, microscopy, dynamic vapor sorption (DVS), and stability testing for 4 months at different storage conditions. Homogeneously distributed drug-PVP associates were observed when nonaqueous emulsions, containing drug-PVP (inner phase) and silicone adhesive (outer phase), were dried to films. DVS data were essential to predict physical stability at different humidities. A predictive thermodynamic model was developed based on drug-polymer hydrogen-bonding interactions, using the Hoffman equation, to estimate the drug-PVP ratio needed to obtain stable MTDDS and to evaluate the impact of humidity on their physical stability. This new approach considers the impact of polymorphism on drug solubility by using easily accessible experimental data (T m and DVS) and avoids uncertainties associated with the solubility parameter approach. In conclusion, a good fit of predicted and experimental data was observed. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  6. Delivery of iPS-NPCs to the Stroke Cavity within a Hyaluronic Acid Matrix Promotes the Differentiation of Transplanted Cells

    Science.gov (United States)

    Lam, Jonathan; Lowry, William E.; Carmichael, S. Thomas; Segura, Tatiana

    2015-01-01

    Stroke is the leading cause of adult disability with ~80% being ischemic. Stem cell transplantation has been shown to improve functional recovery. However, the overall survival and differentiation of these cells is still low. The infarct cavity is an ideal location for transplantation as it is directly adjacent to the highly plastic peri-infarct region. Direct transplantation of cells near the infarct cavity has resulted in low cell viability. Here we deliver neural progenitor cells derived from induce pluripotent stem cells (iPS-NPC) to the infarct cavity of stroked mice encapsulated in a hyaluronic acid hydrogel matrix to protect the cells. To improve the overall viability of transplanted cells, each step of the transplantation process was optimized. Hydrogel mechanics and cell injection parameters were investigated to determine their effects on the inflammatory response of the brain and cell viability, respectively. Using parameters that balanced the desire to keep surgery invasiveness minimal and cell viability high, iPS-NPCs were transplanted to the stroke cavity of mice encapsulated in buffer or the hydrogel. While the hydrogel did not promote stem cell survival one week post-transplantation, it did promote differentiation of the neural progenitor cells to neuroblasts. PMID:26213530

  7. Biointerfacial phenomena of amlodipine buccomucosal tablets of HPMC matrix system containing polyacrylate polymer/β-cyclodextrin: Correlation of swelling and drug delivery performance.

    Science.gov (United States)

    Panda, Brajabihari; Subhadarsini, Rajalaxmi; Mallick, Subrata

    2016-01-01

    This study focuses on the development of amlodipine bilayer buccal tablets of hydroxypropyl methylcellulose (HPMC) matrix system containing polyacrylate polymer (Carbopol(®))/β-cyclodextrin as the drug layer and ethylcellulose as the non-swellable backing layer, and their biointerfacial phenomena. Tablets were evaluated for swelling, erosion and mucoadhesion using buccal mucosal tissue ex vivo. In vitro drug release and ex vivo drug transport across mucosal tissue were also performed in phosphate buffer (pH 6.8). The relationship of swelling with buccoadhesion and buccal permeation of various bilayer tablet formulations containing HPMC alone and in combination with Carbopol or drug-β-cyclodextrin complex has been prepared. Overall buccoadhesion of the tablet with combination of HPMC and Carbopol was increased significantly compared with that of HPMC alone. Presence of cyclodextrin did not change bioadhesion force and swelling behavior significantly. Ex vivo permeation was increased with the increase of HPMC proportion in other formulations as observed in in vitro dissolution. Drug-cyclodextrin complexes in the tablet improved permeation due to its improved dissolution at the site of biointerface of tablet and buccomucosa. Correlations of ex vivo and in vitro data have been established to predict the buccomucosal permeation from the swelling index or drug release alone.

  8. Layered nanoemulsions as mucoadhesive buccal systems for controlled delivery of oral cancer therapeutics

    Directory of Open Access Journals (Sweden)

    Gavin A

    2015-02-01

    Full Text Available Amy Gavin,1 Jimmy TH Pham,2 Dawei Wang,2 Bill Brownlow,3 Tamer A Elbayoumi3 1College of Dental Medicine, 2Arizona College of Osteopathic Medicine, 3Department of Pharmaceutical Sciences, College of Pharmacy-Glendale, Midwestern University, Glendale, AZ, USA Abstract: Oral cavity and oropharyngeal cancers are considered the eighth most common cancer worldwide, with relatively poor prognosis (62% of patients surviving 5 years, after diagnosis. The aim of this study was to develop a proof-of-concept mucoadhesive lozenge/buccal tablet, as a potential platform for direct sustained delivery of therapeutic antimitotic nanomedicines. Our system would serve as an adjuvant therapy for oral cancer patients undergoing full-scale diagnostic and operative treatment plans. We utilized lipid-based nanocarriers, namely nanoemulsions (NEs, containing mixed-polyethoxylated emulsifiers and a tocopheryl moiety–enriched oil phase. Prototype NEs, loaded with the proapoptotic lipophilic drug genistein (Gen, were further processed into buccal tablet formulations. The chitosan polyelectrolyte solution overcoat rendered NE droplets cationic, by acting as a mucoadhesive interfacial NE layer. With approximate size of 110 nm, the positively charged chitosan-layered NE (+25 mV vs negatively charged chitosan-free/primary aqueous NE (-28 mV exhibited a controlled-release profile and effective mucoadhesion for liquid oral spray prototypes. When punch-pressed, porous NE-based buccal tablets were physically evaluated for hardness, friability, and swelling in addition to ex vivo tissue mucoadhesion force and retention time measurements. Chitosan-containing NE tablets were found equivalent to primary NE and placebo tablets in compression tests, yet significantly superior in all ex vivo adhesion and in vitro release assays (P≤0.05. Following biocompatibility screening of prototype chitosan-layered NEs, substantial anticancer activity of selected cationic Gen-loaded NE

  9. Optimization of an efficient transcuticular delivery system for control of citrus huanglongbing

    Science.gov (United States)

    We experimentally develop and optimize a transcuticular nano-delivery system for enhancing permeation of effective compound against HLB disease through citrus cuticle into the phloem by foliar spray or bark application. The results showed that two kinds of nanoemulsions (W/O and O/W) with the smalle...

  10. Thiolated polymers as mucoadhesive drug delivery systems.

    Science.gov (United States)

    Duggan, Sarah; Cummins, Wayne; O' Donovan, Orla; Hughes, Helen; Owens, Eleanor

    2017-03-30

    Mucoadhesion is the process of binding a material to the mucosal layer of the body. Utilising both natural and synthetic polymers, mucoadhesive drug delivery is a method of controlled drug release which allows for intimate contact between the polymer and a target tissue. It has the potential to increase bioavailability, decrease potential side effects and offer protection to more sensitive drugs such as proteins and peptide based drugs. The thiolation of polymers has, in the last number of years, come to the fore of mucoadhesive drug delivery, markedly improving mucoadhesion due to the introduction of free thiol groups onto the polymer backbone while also offering a more cohesive polymeric matrix for the slower and more controlled release of drug. This review explores the concept of mucoadhesion and the recent advances in both the polymers and the methods of thiolation used in the synthesis of mucoadhesive drug delivery devices. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Cellular versus acellular matrix devices in treatment of diabetic foot ulcers: study protocol for a comparative efficacy randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Lev-Tov Hadar

    2013-01-01

    Full Text Available Abstract Background Diabetic foot ulcers (DFUs represent a significant source of morbidity and an enormous financial burden. Standard care for DFUs involves systemic glucose control, ensuring adequate perfusion, debridement of nonviable tissue, off-loading, control of infection, local wound care and patient education, all administered by a multidisciplinary team. Unfortunately, even with the best standard of care (SOC available, only 24% or 30% of DFUs will heal at weeks 12 or 20, respectively. The extracellular matrix (ECM in DFUs is abnormal and its impairment has been proposed as a key target for new therapeutic devices. These devices intend to replace the aberrant ECM by implanting a matrix, either devoid of cells or enhanced with fibroblasts, keratinocytes or both as well as various growth factors. These new bioengineered skin substitutes are proposed to encourage angiogenesis and in-growth of new tissue, and to utilize living cells to generate cytokines needed for wound repair. To date, the efficacy of bioengineered ECM containing live cellular elements for improving healing above that of a SOC control group has not been compared with the efficacy of an ECM devoid of cells relative to the same SOC. Our hypothesis is that there is no difference in the improved healing effected by either of these two product types relative to SOC. Methods/Design To test this hypothesis we propose a randomized, single-blind, clinical trial with three arms: SOC, SOC plus Dermagraft® (bioengineered ECM containing living fibroblasts and SOC plus Oasis® (ECM devoid of living cells in patients with nonhealing DFUs. The primary outcome is the percentage of subjects that achieved complete wound closure by week 12. Discussion If our hypothesis is correct, then immense cost savings could be realized by using the orders-of-magnitude less expensive acellular ECM device without compromising patient health outcomes. The article describes the protocol proposed to test

  12. Tissue-specific and SRSF1-dependent splicing of fibronectin, a matrix protein that controls host cell invasion

    Science.gov (United States)

    Lopez-Mejia, Isabel Cristina; De Toledo, Marion; Della Seta, Flavio; Fafet, Patrick; Rebouissou, Cosette; Deleuze, Virginie; Blanchard, Jean Marie; Jorgensen, Christian; Tazi, Jamal; Vignais, Marie-Luce

    2013-01-01

    Cell invasion targets specific tissues in physiological placental implantation and pathological metastasis, which raises questions about how this process is controlled. We compare dermis and endometrium capacities to support trophoblast invasion, using matching sets of human primary fibroblasts in a coculture assay with human placental explants. Substituting endometrium, the natural trophoblast target, with dermis dramatically reduces trophoblast interstitial invasion. Our data reveal that endometrium expresses a higher rate of the fibronectin (FN) extra type III domain A+ (EDA+) splicing isoform, which displays stronger matrix incorporation capacity. We demonstrate that the high FN content of the endometrium matrix, and not specifically the EDA domain, supports trophoblast invasion by showing that forced incorporation of plasma FN (EDA–) promotes efficient trophoblast invasion. We further show that the serine/arginine-rich protein serine/arginine-rich splicing factor 1 (SRSF1) is more highly expressed in endometrium and, using RNA interference, that it is involved in the higher EDA exon inclusion rate in endometrium. Our data therefore show a mechanism by which tissues can be distinguished, for their capacity to support invasion, by their different rates of EDA inclusion, linked to their SRSF1 protein levels. In the broader context of cancer pathology, the results suggest that SRSF1 might play a central role not only in the tumor cells, but also in the surrounding stroma. PMID:23966470

  13. Portable Video Media Versus Standard Verbal Communication in Surgical Information Delivery to Nurses: A Prospective Multicenter, Randomized Controlled Crossover Trial.

    Science.gov (United States)

    Kam, Jonathan; Ainsworth, Hannah; Handmer, Marcus; Louie-Johnsun, Mark; Winter, Matthew

    2016-10-01

    Continuing education of health professionals is important for delivery of quality health care. Surgical nurses are often required to understand surgical procedures. Nurses need to be aware of the expected outcomes and recognize potential complications of such procedures during their daily work. Traditional educational methods, such as conferences and tutorials or informal education at the bedside, have many drawbacks for delivery of this information in a universal, standardized, and timely manner. The rapid uptake of portable media devices makes portable video media (PVM) a potential alternative to current educational methods. To compare PVM to standard verbal communication (SVC) for surgical information delivery and educational training for nurses and evaluate its impact on knowledge acquisition and participant satisfaction. Prospective, multicenter, randomized controlled crossover trial. Two hospitals: Gosford District Hospital and Wyong Hospital. Seventy-two nursing staff (36 at each site). Information delivery via PVM--7-minute video compared to information delivered via SVC. Knowledge acquisition was measured by a 32-point questionnaire, and satisfaction with the method of education delivery was measured using the validated Client Satisfaction Questionnaire (CSQ-8). Knowledge acquisition was higher via PVM compared to SVC 25.9 (95% confidence interval [CI] 25.2-26.6) versus 24.3 (95% CI 23.5-25.1), p = .004. Participant satisfaction was higher with PVM 29.5 (95% CI 28.3-30.7) versus 26.5 (95% CI 25.1-27.9), p = .003. Following information delivery via SVC, participants had a 6% increase in knowledge scores, 24.3 (95% CI 23.5-25.1) versus 25.7 (95% CI 24.9-26.5) p = .001, and a 13% increase in satisfaction scores, 26.5 (95% CI 25.1-27.9) versus 29.9 (95% CI 28.8-31.0) p < .001, when they crossed-over to information delivery via PVM. PVM provides a novel method for providing education to nurses that improves knowledge retention and satisfaction with the

  14. Effects of epidural lidocaine analgesia on labor and delivery: A randomized, prospective, controlled trial

    Directory of Open Access Journals (Sweden)

    Nafisi Shahram

    2006-12-01

    Full Text Available Abstract Background Whether epidural analgesia for labor prolongs the active-first and second labor stages and increases the risk of vacuum-assisted delivery is a controversial topic. Our study was conducted to answer the question: does lumbar epidural analgesia with lidocaine affect the progress of labor in our obstetric population? Method 395 healthy, nulliparous women, at term, presented in spontaneous labor with a singleton vertex presentation. These patients were randomized to receive analgesia either, epidural with bolus doses of 1% lidocaine or intravenous, with meperidine 25 to 50 mg when their cervix was dilated to 4 centimeters. The duration of the active-first and second stages of labor and the neonatal apgar scores were recorded, in each patient. The total number of vacuum-assisted and cesarean deliveries were also measured. Results 197 women were randomized to the epidural group. 198 women were randomized to the single-dose intravenous meperidine group. There was no statistical difference in rates of vacuum-assisted delivery rate. Cesarean deliveries, as a consequence of fetal bradycardia or dystocia, did not differ significantly between the groups. Differences in the duration of the active-first and the second stages of labor were not statistically significant. The number of newborns with 1-min and 5-min Apgar scores less than 7, did not differ significantly between both analgesia groups. Conclusion Epidural analgesia with 1% lidocaine does not prolong the active-first and second stages of labor and does not increase vacuum-assisted or cesarean delivery rate.

  15. Matrix elasticity of void-forming hydrogels controls transplanted-stem-cell-mediated bone formation

    Science.gov (United States)

    Huebsch, Nathaniel; Lippens, Evi; Lee, Kangwon; Mehta, Manav; Koshy, Sandeep T.; Darnell, Max C.; Desai, Rajiv M.; Madl, Christopher M.; Xu, Maria; Zhao, Xuanhe; Chaudhuri, Ovijit; Verbeke, Catia; Kim, Woo Seob; Alim, Karen; Mammoto, Akiko; Ingber, Donald E.; Duda, Georg N.; Mooney, David J.

    2015-12-01

    The effectiveness of stem cell therapies has been hampered by cell death and limited control over fate. These problems can be partially circumvented by using macroporous biomaterials that improve the survival of transplanted stem cells and provide molecular cues to direct cell phenotype. Stem cell behaviour can also be controlled in vitro by manipulating the elasticity of both porous and non-porous materials, yet translation to therapeutic processes in vivo remains elusive. Here, by developing injectable, void-forming hydrogels that decouple pore formation from elasticity, we show that mesenchymal stem cell (MSC) osteogenesis in vitro, and cell deployment in vitro and in vivo, can be controlled by modifying, respectively, the hydrogel’s elastic modulus or its chemistry. When the hydrogels were used to transplant MSCs, the hydrogel’s elasticity regulated bone regeneration, with optimal bone formation at 60 kPa. Our findings show that biophysical cues can be harnessed to direct therapeutic stem cell behaviours in situ.

  16. Construction and evaluation of controlled-release delivery system of Abamectin using porous silica nanoparticles as carriers.

    Science.gov (United States)

    Wang, Yan; Cui, Haixin; Sun, Changjiao; Zhao, Xiang; Cui, Bo

    2014-12-01

    Photolysis and poor solubility in water of Abamectin are key issues to be addressed, which causes low bioavailability and residual pollution. In this study, a novel hydrophilic delivery system through loading Abamectin with porous silica nanoparticles (Abam-PSNs) was developed in order to improve the chemical stability, dispersity, and the controlled release of Abamectin. These results suggest that Abam-PSNs can significantly improve the performance of controllable release, photostability, and water solubility of Abamectin by changing the porous structure of silica nanoparticles, which is favorable to improve the bioavailability and reduce the residues of pesticides.

  17. Advances in oral controlled drug delivery: the role of drug-polymer and interpolymer non-covalent interactions.

    Science.gov (United States)

    De Robertis, Simona; Bonferoni, Maria Cristina; Elviri, Lisa; Sandri, Giuseppina; Caramella, Carla; Bettini, Ruggero

    2015-03-01

    After more than four decades of intense research, oral controlled drug delivery systems (DDSs) still represent a topic of major interest for pharmaceutical scientist and formulators. This can be explained in part by considering the economic value of oral DDSs whose market accounts for more than half of the overall drug delivery market. Polymeric systems based on drug-polymer non-covalent interaction represent a limited, but growing part of the field. Despite the large amount of literature and published reviews covering specific aspects, there is still need for a review of the relevant literature providing a general picture of the topic. The present review aims at presenting the latest findings in drug-polymer and interpolymer non-covalent interactions in oral controlled delivery while providing a specific perspective and a critical point of view, particularly on the tools and methods used for the study of these DDSs. Four main sections are considered: i) ionic interactions between drugs and polymers; ii) interpolymer complexes; iii) hydrogen bond; and iv) hydrophobic interactions. The largest part of the scientific literature deals with systems based on drug-polymer ionic interactions while hydrogen bonding and hydrophobic interaction though, very promising, are more difficult to exploit, and therefore less studied. An accurate and exhaustive representation of the specific role of the chemical functions in establishing predictable interactions between drug and polymers is still required.

  18. Randomized controlled trial of the effect of 30% versus 80% fraction of inspired oxygen on cesarean delivery surgical site infection.

    Science.gov (United States)

    Williams, Ned L; Glover, Melanie M; Crisp, Catrina; Acton, Angus L; Mckenna, David S

    2013-10-01

    To determine if supplemental perioperative oxygen will reduce surgical site infection (SSI) following cesarean delivery. This is a randomized, controlled trial evaluating SSI following either 30% or 80% fraction of inspired oxygen (FIO2) during and 2 hours after cesarean delivery. Anesthesia providers administered FIO2 via a high-flow oxygen blender. Subjects, surgeons, and wound evaluation teams were blinded. Serial wound evaluations were performed. Data were analyzed using logistic regression models, Fisher exact test, and t test. In all, 179 women were randomized, and 160 subjects were included in the analysis. There were 12/83 (14.5%) SSIs in the control group versus 10/77 (13.0%) in the investigational group (p = 0.82). Caucasian race, increased body mass index, and longer operative time were identified as significant risk factors for infection (p = 0.026, odds ratio 0.283; p = 0.05, odds ratio = 1.058; p = 0.037, odds ratio = 1.038, respectively). Perioperative oxygenation with 80% Fio2 is not effective in reducing SSI following cesarean delivery. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  19. Controlled release matrix uncoated tablets of enalapril maleate using hpmc alone.

    Science.gov (United States)

    Nair, Anroop B; Vyas, Hiral; Kumar, Ashok

    2010-03-01

    Hydroxy propyl methyl cellulose (HPMC) is generally combined with hydrophobic polymers in fabricating oral controlled solid dosage forms. This study evaluated the utility of diverse grades of HPMC in developing a controlled release formulation for a hydrophilic drug, enalapril maleate. Controlled release uncoated tablets were prepared by direct compression technique. Two grades of HPMC (K100 and K4M) in different proportions were used to prepare the tablets, and were evaluated for physical properties, drug content, in vitro drug release and drug release kinetics as well. All the formulations demonstrated good physical integrity and the drug content were in the official limits. The formulation with HPMC K100 (25 mg/tablet) and K4M (15 mg/tablet) have been found to release the required amount of drug (2.97 mg/h) through out the study period (14 h). The calculated regression coefficients showed higher r(2) value with Higuchi model and zero order kinetics. Given the excellent release profile, the study concluded that HPMC in different grades with low concentration alone can control the enalapril maleate release over a period of time (14 h).

  20. Using matrix population models to inform biological control management of the wheat stem sawfly, Cephus cinctus

    Science.gov (United States)

    Demographic models are a powerful means of identifying vulnerable life stages of pest species and assessing the potential effectiveness of various management approaches in reducing pest population growth and spread. In a biological control context, such models can be used to focus foreign explorati...

  1. Investigating output and energy variations and their relationship to delivery QA results using Statistical Process Control for helical tomotherapy.

    Science.gov (United States)

    Binny, Diana; Mezzenga, Emilio; Lancaster, Craig M; Trapp, Jamie V; Kairn, Tanya; Crowe, Scott B

    2017-06-01

    The aims of this study were to investigate machine beam parameters using the TomoTherapy quality assurance (TQA) tool, establish a correlation to patient delivery quality assurance results and to evaluate the relationship between energy variations detected using different TQA modules. TQA daily measurement results from two treatment machines for periods of up to 4years were acquired. Analyses of beam quality, helical and static output variations were made. Variations from planned dose were also analysed using Statistical Process Control (SPC) technique and their relationship to output trends were studied. Energy variations appeared to be one of the contributing factors to delivery output dose seen in the analysis. Ion chamber measurements were reliable indicators of energy and output variations and were linear with patient dose verifications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  2. The economy-wide impact of controlling energy consumption in Indonesia: An analysis using a Social Accounting Matrix framework

    International Nuclear Information System (INIS)

    Hartono, Djoni; Resosudarmo, Budy P.

    2008-01-01

    Escalating oil prices and the need to control carbon emissions sound the alarm for Indonesia to reduce or be more efficient in its energy use. Instead of eliminating the fuel oil subsidy to promote better and more efficient use of energy, the Indonesian government seems to be more in favour of restricting energy use by, for example, requiring all hotels, restaurants, night clubs and other business activities to close down by 1 am. Societies need to understand the full consequences of adopting restricting energy use and more efficient energy use strategies toward their incomes. This paper aims to analyse the impact on the economy of energy policies aiming to reduce and to improve the efficiency of energy use, particularly on the income of various household groups. This paper will, first, construct a Social Accounting Matrix for Indonesia with detailed energy sectors and, second, utilise various multiplier analyses to observe and understand the impact of these energy policies

  3. Load Sharing Using Droop Control for Parallel Operation of Matrix Converters as Distributed Generator Interfaces in Isolated Mode

    DEFF Research Database (Denmark)

    Liu, Xiong; Loh, Poh Chiang; Blaabjerg, Frede

    2012-01-01

    DGs to share common loads in isolated operation mode. Through the adjustment of load side frequency and voltage amplitude using the droop characteristic of P/ω and Q/V, the load side active/reactive powers can be shared properly among the DGs. Load side voltages and generator side currents should......Matrix converter (MC) can be used as ac type distributed generator (DG) interface in microgrid. Reverse power flow operation of MC can be implemented to meet voltage boost requirement, where the input ac generator is connected to the converter's voltage source side and the output utility grid...... or load is connected to the current source side. During grid fault or intentional islanded operation, the DGs need to supply local loads with high quality voltage and share the loads proportionally to their power ratings. This paper proposes droop control strategy for two parallel MCs with two separate...

  4. Dependence of CIT [Compact Ignition Tokamak] PF [poloidal field] coil currents on profile and shape parameters using the Control Matrix

    International Nuclear Information System (INIS)

    Strickler, D.J.; Peng, Y-K.M.; Jardin, S.C.; Pomphrey, N.

    1990-01-01

    The plasma shaping flexibility of the Compact Ignition Tokamak (CIT) poloidal field (PF) coil set is demonstrated through MHD equilibrium calculations of optimal PF coil current distributions and their variation with poloidal beta, internal inductance, plasma 95% elongation, and 95% triangularity. Calculations of the magnetic stored energy are used to compare solutions associated with various plasma parameters. The Control Matrix (CM) equilibrium code, together with the nonlinear equation and numerical optimization software packages HYBRD, and VMCON, respectively, are used to find equilibrium coil current distributions for fixed divertor geometry, volt-seconds, and plasma profiles in order to isolate the dependence on individual parameters. A reference equilibrium and coil current distribution are chosen, and correction currents dI are determined using the CM equilibrium method to obtain other specified plasma shapes. The reference equilibrium is the κ = 2 divertor at beginning of flattop (BOFT) with a minimum stored energy solution for the coil current distribution. The pressure profile function is fixed

  5. The effect of perineal control with hands-on and hand-poised methods on perineal trauma and delivery outcome

    Directory of Open Access Journals (Sweden)

    Azam Foroughipour

    2011-01-01

    Full Text Available Background: The objective of the present study was to evaluate the effect of the two methods of delivery, "hands-on" vs. "hands poised", on perineal trauma and delivery outcome in primiparous women referred to Shariati Hospital of Isfahan during 2007-2008. Methods: In a clinical trial study, 100 low risk primiparous pregnant women were randomly assigned to two hands-on and hand-poised (hands-off groups. In the hands-on group, this method was used to control fetal head in the second stage of labor. It means that the fingers of one hand supported fetal occiput and the other hand applied slight pressure on the head to control the delivery of the head during the crowning process. In the hands-poised group, midwife observed the parturient woman and do not touch perineum during the second labor stage while fetal head was delivering. Then, the two groups were compared in terms of perineal trauma, as well as neonatal and delivery outcome. Results: Demographic characteristics of all studied women were similar in two groups. The rate of episiotomy was higher in hands-on group (84% vs. 40%, p = 0.001. The rate of postpartum hemorrhage (4 th stage was higher in hands-on group (12% vs. 4%, p = 0.04. The rate of mild and moderate postpartum pain in hands-on group was higher than hands-off group (70% vs. 58% and 29% vs. 10%, p < 0.001 but sever pain was not different in two groups. Conclusions: It seems that hands-poised method is associated with less perineal trauma, particularly regarding the lower need for episiotomy and postpartum hemorrhage.

  6. Simultaneous hyperthermia-chemotherapy with controlled drug delivery using single-drug nanoparticles

    OpenAIRE

    Sato, Itaru; Umemura, Masanari; Mitsudo, Kenji; Fukumura, Hidenobu; Kim, Jeong-Hwan; Hoshino, Yujiro; Nakashima, Hideyuki; Kioi, Mitomu; Nakakaji, Rina; Sato, Motohiko; Fujita, Takayuki; Yokoyama, Utako; Okumura, Satoshi; Oshiro, Hisashi; Eguchi, Haruki

    2016-01-01

    We previously investigated the utility of ?-oxo N,N?- bis(salicylidene)ethylenediamine iron (Fe(Salen)) nanoparticles as a new anti-cancer agent for magnet-guided delivery with anti-cancer activity. Fe(Salen) nanoparticles should rapidly heat up in an alternating magnetic field (AMF), and we hypothesized that these single-drug nanoparticles would be effective for combined hyperthermia-chemotherapy. Conventional hyperthermic particles are usually made of iron oxide, and thus cannot exhibit ant...

  7. Nuclear track microfilters in controlled drug delivery against chronic skin disease

    International Nuclear Information System (INIS)

    Nuclear track microfilters have been developed for transdermal therapeutic system. The transdermal therapeutic method reduces the toxicity of the drug as compared to other conventional methods. For this purpose a slow drug release system containing the nuclear track microfilter was developed. This device was applied to the patients suffering from psoriasis and cellulites diseases. The delivery of the drug to the patient was confirmed through high performance liquid chromatography. The preliminary results have shown that patients are responding to drugs with minimum toxicity

  8. Nuclear track microfilters in controlled drug delivery against chronic skin disease

    Energy Technology Data Exchange (ETDEWEB)

    Gopalani, D. E-mail: deflab@sancharnet.in; Jodha, A.S.; Saravanan, S.; Kumar, S

    2003-06-01

    Nuclear track microfilters have been developed for transdermal therapeutic system. The transdermal therapeutic method reduces the toxicity of the drug as compared to other conventional methods. For this purpose a slow drug release system containing the nuclear track microfilter was developed. This device was applied to the patients suffering from psoriasis and cellulites diseases. The delivery of the drug to the patient was confirmed through high performance liquid chromatography. The preliminary results have shown that patients are responding to drugs with minimum toxicity.

  9. Study Protocol. IDUS -- Instrumental delivery & ultrasound. A multi-centre randomised controlled trial of ultrasound assessment of the fetal head position versus standard care as an approach to prevent morbidity at instrumental delivery

    LENUS (Irish Health Repository)

    Murphy, Deirdre J

    2012-09-13

    AbstractBackgroundInstrumental deliveries are commonly performed in the United Kingdom and Ireland, with rates of 12 – 17% in most centres. Knowing the exact position of the fetal head is a pre-requisite for safe instrumental delivery. Traditionally, diagnosis of the fetal head position is made on transvaginal digital examination by delineating the suture lines of the fetal skull and the fontanelles. However, the accuracy of transvaginal digital examination can be unreliable and varies between 20% and 75%. Failure to identify the correct fetal head position increases the likelihood of failed instrumental delivery with the additional morbidity of sequential use of instruments or second stage caesarean section. The use of ultrasound in determining the position of the fetal head has been explored but is not part of routine clinical practice.Methods\\/DesignA multi-centre randomised controlled trial is proposed. The study will take place in two large maternity units in Ireland with a combined annual birth rate of 13,500 deliveries. It will involve 450 nulliparous women undergoing instrumental delivery after 37 weeks gestation. The main outcome measure will be incorrect diagnosis of the fetal head position. A study involving 450 women will have 80% power to detect a 10% difference in the incidence of inaccurate diagnosis of the fetal head position with two-sided 5% alpha.DiscussionIt is both important and timely to evaluate the use of ultrasound to diagnose the fetal head position prior to instrumental delivery before routine use can be advocated. The overall aim is to reduce the incidence of incorrect diagnosis of the fetal head position prior to instrumental delivery and improve the safety of instrumental deliveries.Trial registrationCurrent Controlled Trials ISRCTN72230496

  10. Polylactide-co-glycolide nanoparticles for controlled delivery of anticancer agents

    Directory of Open Access Journals (Sweden)

    Rouhani H

    2011-04-01

    Full Text Available R Dinarvand1,2, N Sepehri1, S Manoochehri1, H Rouhani1, F Atyabi1,21Department of Pharmaceutics, Faculty of Pharmacy, 2Nanotechnology Research Centre, Tehran University of Medical Sciences, Tehran, IranAbstract: The effectiveness of anticancer agents may be hindered by low solubility in water, poor permeability, and high efflux from cells. Nanomaterials have been used to enable drug delivery with lower toxicity to healthy cells and enhanced drug delivery to tumor cells. Different nanoparticles have been developed using different polymers with or without surface modification to target tumor cells both passively and/or actively. Polylactide-co-glycolide (PLGA, a biodegradable polyester approved for human use, has been used extensively. Here we report on recent developments concerning PLGA nanoparticles prepared for cancer treatment. We review the methods used for the preparation and characterization of PLGA nanoparticles and their applications in the delivery of a number of active agents. Increasing experience in the field of preparation, characterization, and in vivo application of PLGA nanoparticles has provided the necessary momentum for promising future use of these agents in cancer treatment, with higher efficacy and fewer side effects.Keywords: nanotechnology, polymeric nanocarriers, targeting, anticancer agents, surface modification

  11. Matrix theory

    CERN Document Server

    Franklin, Joel N

    2003-01-01

    Mathematically rigorous introduction covers vector and matrix norms, the condition-number of a matrix, positive and irreducible matrices, much more. Only elementary algebra and calculus required. Includes problem-solving exercises. 1968 edition.

  12. Electrically conductive, black thermal control coatings for spacecraft applications. III - Plasma-deposited ceramic matrix

    Science.gov (United States)

    Hribar, V. F.; Bauer, J. L.; O'Donnell, T. P.

    1987-01-01

    Five black, electrically-conductive thermal control coatings have been formulated and tested for application on the Galileo spacecraft. The coatings consist of both organic and inorganic systems applied on titanium, aluminum, and glass/epoxy composite surfaces. The coatings were tested under simulated space environment conditions. Coated specimens were subjected to thermal radiation, convective and combustive heating, and cryogenic conditions over a temperature range between -196 C and 538 C. Mechanical, physical, thermal, electrical, and thermooptical properties are presented for one of these coatings. This paper describes the preparation, characteristics, and spraying of iron titanate on titanium and aluminum, and presents performance results.

  13. Voice-Controlled and Wireless Solid Set Canopy Delivery (VCW-SSCD System for Mist-Cooling

    Directory of Open Access Journals (Sweden)

    Yiannis Ampatzidis

    2018-02-01

    Full Text Available California growers in the San Joaquin Valley believe that climate change will affect the pistachio yield dramatically. As the central valley fog disappears, insufficient dormant chill accumulation results in poor flowering synchrony, flower quality, and fruit set in this dioecious species. We have developed a novel, user-friendly, and low-cost Voice-Controlled Wireless Solid Set Canopy Delivery (VCW-SSCD system to increase bud chill accumulation with evaporative cooling on sunny (winter days. This system includes: (i an automated solid-state canopy delivery (SSCD system; (ii a wireless weather-, crop-related data acquisition system; (iii a Voice-Controlled (VC system using Amazon Alexa; (iv a mobile application to visualize the collected data and wirelessly control the SSCD system; and (v a smart control system. The proposed system was deployed and evaluated in a commercial pistachio orchard in Bakersfield, CA. The system worked well with no reported errors. Results demonstrated the system’s ability to cool bud temperatures in a low relative humidity climate. At an ambient temperature of 10–20 °C, bud temperatures were lowered 5–10 °C.

  14. Field-controllable Spin-Hall Effect of Light in Optical Crystals: A Conoscopic Mueller Matrix Analysis.

    Science.gov (United States)

    Samlan, C T; Viswanathan, Nirmal K

    2018-01-31

    Electric-field applied perpendicular to the direction of propagation of paraxial beam through an optical crystal dynamically modifies the spin-orbit interaction (SOI), leading to the demonstration of controllable spin-Hall effect of light (SHEL). The electro- and piezo-optic effects of the crystal modifies the radially symmetric spatial variation in the fast-axis orientation of the crystal, resulting in a complex pattern with different topologies due to the symmetry-breaking effect of the applied field. This introduces spatially-varying Pancharatnam-Berry type geometric phase on to the paraxial beam of light, leading to the observation of SHEL in addition to the spin-to-vortex conversion. A wave-vector resolved conoscopic Mueller matrix measurement and analysis provides a first glimpse of the SHEL in the biaxial crystal, identified via the appearance of weak circular birefringence. The emergence of field-controllable fast-axis orientation of the crystal and the resulting SHEL provides a new degree of freedom for affecting and controlling the spin and orbital angular momentum of photons to unravel the rich underlying physics of optical crystals and aid in the development of active photonic spin-Hall devices.

  15. Speed Control of Matrix Converter-Fed Five-Phase Permanent Magnet Synchronous Motors under Unbalanced Voltages

    Directory of Open Access Journals (Sweden)

    Borzou Yousefi

    2017-09-01

    Full Text Available Five-phase permanent magnet synchronous motors (PMSM have special applications in which highly accurate speed and torque control of the motor are a strong requirement. Direct Torque Control (DTC is a suitable method for the driver structure of these motors. If in this method, instead of using a common five-phase voltage source inverter, a three-phase to five-phase matrix converter is used, the low-frequency current harmonics and the high torque ripple are limited, and an improved input power factor is obtained. Because the input voltages of such converters are directly supplied by input three-phase supply voltages, an imbalance in the voltages will cause problems such as unbalanced stator currents and electromagnetic torque fluctuations. In this paper, a new method is introduced to remove speed and torque oscillator factors. For this purpose, motor torque equations were developed and the oscillation components created by the unbalanced source voltage, determined. Then, using the active and reactive power reference generator, the controller power reference was adjusted in such a way that the electromagnetic torque of the motor did not change. By this means, a number of features including speed, torque, and flux of the motor were improved in terms of the above-mentioned conditions. Simulations were analyzed using Matlab/Simulink software.

  16. Development of Gold Nanoparticle towards Radioenhancement Therapy, Renal Clearance, siRNA Delivery and Light-Controlled Gene Silencing

    Science.gov (United States)

    Wang, Jianxin

    Gold nanoparticles (GNPs) have been widely studied and used in research for diagnostic, prophylactic or therapeutic purposes. However, they still face many technical challenges before they can be used to effectively address unmet biomedical needs. The theme of this dissertation is focused on addressing challenges of GNPs in clinical translation, and to improve their potential for application in radioenhancement therapy and siRNA delivery. We demonstrate the facile self-assembly of micellar gold nanocapsules using zwitterionic surfactants, with hydrodynamic diameters below 10 nm, which holds promise for good renal clearance to promote the excretion of GNPs in human body. We also prepared PEI- and PEG-coated GNPs and demonstrated their uptake into HeLa cells with exposure to soft X-rays (120 kVp), based on the consideration that the proximity of GNPs to nuclear DNA may be beneficial for enhancing low-energy ionizing radiotherapy. GNP-mediated siRNA delivery may be challenged by nonspecific siRNA desorption during circulation, which can cause off-target effects and immunogenicity. The use of gold nanorods (GNRs) for siRNA delivery also faces challenges like reduced dispersion stability during siRNA functionalization. We developed an effective way to load siRNA onto GNRs at high density, using oleylsulfobetaine (OSB) as an intermediate surfactant and dithiocarbamates (DTCs) as desorption-resistant anchors for siRNA. The GNR?siRNA complexes provided excellent control for laser-triggered gene silencing.

  17. Randomized controlled trial comparing carbetocin, misoprostol, and oxytocin for the prevention of postpartum hemorrhage following an elective cesarean delivery.

    Science.gov (United States)

    Elbohoty, Ahmed E H; Mohammed, Walid E; Sweed, Mohamed; Bahaa Eldin, Ahmed M; Nabhan, Ashraf; Abd-El-Maeboud, Karim H I

    2016-09-01

    To compare the effectiveness and safety of carbetocin, misoprostol, and oxytocin for the prevention of postpartum hemorrhage following cesarean deliveries. A double-blind randomized controlled trial enrolled patients with a singleton pregnancy scheduled for an elective cesarean delivery at a maternity hospital in Cairo, Egypt, between October 1, 2012 and June 30, 2013. Participants were randomized using a computer-generated sequence to receive treatment with carbetocin, misoprostol, or oxytocin. The primary outcome was the occurrence of uterine atony necessitating additional uterotonics. Per-protocol analyses were performed. Patients, investigators, and data analysts were masked to treatment assignments. The present study enrolled 263 patients; data were analyzed from 88 patients treated with carbetocin, 89 treated with misoprostol, and 86 women treated with oxytocin. Further uterotonics were needed for the treatment of 5 (6%) patients who were treated with carbetocin, 20 (22%) patients treated with misoprostol, and 11 (13%) patients treated with oxytocin. In the prevention of uterine atony, carbetocin was comparable with oxytocin (RR 0.41, 95%CI 0.14-1.25) and superior to misoprostol (RR 0.21, 95%CI 0.07-0.58). Additional uterotonics were needed less frequently by patients treated with carbetocin. Carbetocin was comparable to oxytocin and superior to misoprostol in the prevention of uterine atony following an elective cesarean delivery. ClinicalTrials.gov: NCT02053922. Copyright © 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  18. Ephedrine versus ondansetron in the prevention of hypotension during cesarean delivery: a randomized, double-blind, placebo-controlled trial.

    Science.gov (United States)

    Nivatpumin, P; Thamvittayakul, V

    2016-08-01

    Maternal hypotension is common after spinal anesthesia for cesarean delivery. We compared the effects of prophylactic ephedrine with ondansetron on post-spinal blood pressure. One hundred and sixty-eight term, singleton parturients were enrolled in this prospective, double-blind, placebo-controlled trial. Patients were randomized to receive either prophylactic intravenous ephedrine 10mg (Group E), ondansetron 8mg (Group O) or normal saline (Group P) immediately after spinal anesthesia. The primary outcome was maternal blood pressure between spinal block and delivery; secondary outcomes were nausea and vomiting scores, Apgar scores, numbers requiring intraoperative vasoconstrictors and the dose of vasoconstrictors required. Fifty-six patients were recruited to each group, but two in Group P were excluded from the analysis owing to protocol violations. There were no significant differences between the groups in maternal systolic, diastolic or mean arterial pressures, or the proportion of patients experiencing hypotension. The proportion of patients in Group E requiring intraoperative ephedrine or any vasoconstrictor (ephedrine and/or norepinephrine) was significantly lower than that in Group P (P=0.023 and 0.034, respectively). The proportion of patients in Group O requiring intraoperative norepinephrine was significantly lower than that in Group P (P=0.02). There was no difference in the proportions of patients in Groups E and O requiring any vasoconstrictors (P=0.34). There was no significant difference in maternal blood pressure in women administered prophylactic ephedrine or ondansetron after spinal anesthesia for cesarean delivery compared with placebo. Ephedrine reduced the proportion of patients requiring a rescue vasoconstrictor before delivery. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Quality of intervention delivery in a cluster randomised controlled trial: a qualitative observational study with lessons for fidelity.

    Science.gov (United States)

    James, Karen; Quirk, Alan; Patterson, Sue; Brennan, Geoff; Stewart, Duncan

    2017-11-17

    Understanding intervention fidelity is an essential part of the evaluation of complex interventions because fidelity not only affects the validity of trial findings, but also because studies of fidelity can be used to identify barriers and facilitators to successful implementation, and so provide important information about factors likely to impact the uptake of the intervention into clinical practice. Participant observation methods have been identified as being particularly valuable in studies of fidelity, yet are rarely used. This study aimed to use these methods to explore the quality of implementation of a complex intervention (Safewards) on mental health wards during a cluster randomised controlled trial. Specific aims were firstly to describe the different ways in which the intervention was implemented, and secondly to explore the contextual factors moderating the quality of intervention delivery, in order to inform 'real world' implementation of the intervention. Safewards was implemented on 16 mental health wards in England. We used Research Assistants (RAs) trained in participant observation to record qualitative observational data on the quality of intervention delivery (n = 565 observations). At the end of the trial, two focus groups were conducted with RAs, which were used to develop the coding framework. Data were analysed using thematic analysis. There was substantial variation in intervention delivery between wards. We observed modifications to the intervention which were both fidelity consistent and inconsistent, and could enhance or dilute the intervention effects. We used these data to develop a typology which describes the different ways in which the intervention was delivered. This typology could be used as a tool to collect qualitative observational data about fidelity during trials. Moderators of Safewards implementation included systemic, interpersonal, and individual factors and patient responses to the intervention. Our study

  20. RGD conjugated liposome-hollow silica hybrid nanovehicles for targeted and controlled delivery of arsenic trioxide against hepatic carcinoma.

    Science.gov (United States)

    Fei, Weidong; Zhang, Yan; Han, Shunping; Tao, Jiaoyang; Zheng, Hongyue; Wei, Yinghui; Zhu, Jiazhen; Li, Fanzhu; Wang, Xuanshen

    2017-03-15

    The aim of our study was to construct an Arg-Gly-Asp (RGD)-conjugated liposome-hollow silica hybrid nanovehicle for targeted delivery and controlled release of arsenic trioxide (ATO), whose anti-solid tumor effect was hampered by poor pharmacokinetics and dose-limited toxicity. Hydrophobic interactions were used to attach intact lipid membrane to the surface of chlorodimethyloctadecylsilane-modified hollow mesoporous silica nanoparticles. The prepared nanovehicles (RGD-LP-CHMSN) were characterized for uniform structure (silica core of ∼140nm in diameter and liposomal shell of ∼6nm), comparable drug loading efficiency (6.76%), desirable stability and strengthened controlled release. In vitro, RGD-LP-CHMSN showed good biocompatibility and low toxicity on HepG2, MCF-7 and LO2 cells. The targeted delivery of ATO by nanocarriers (RGD-LP-CHMSN-ATO) was demonstrated by an enhanced cellular uptake and a reduced half maximal inhibitory concentration (IC 50 ) value. In pharmacokinetic studies, the RGD-LP-CHMSN-ATO group, compared to the free ATO group, prolonged the half time (t 1/2β ) by 1.7 times and increased the area under curve (AUC) by 2.4 times. In addition, in a H22 tumor-xenograft mouse model, nanovehicles improved the targeting efficiency and anticancer potential of ATO. In conclusion, the strategy of constructing a nanocarrier with targeted delivery and controlled release characteristics is prospective to enhance the antitumor effect of ATO. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Salivary microflora and mode of delivery: a prospective case control study.

    Science.gov (United States)

    Boustedt, Katarina; Roswall, Josefine; Dahlén, Gunnar; Dahlgren, Jovanna; Twetman, Svante

    2015-12-03

    Previous cross-sectional studies have suggested that the mode of delivery can influence the composition of oral microflora. The aim of this prospective study was to compare the salivary colonization in vaginally delivered children with children delivered by Caesarian section (C-section) during their first 6 months of life. The study group consisted of 149 consecutively enrolled infants, delivered either vaginally (n = 96) or by C-section (n = 53) that volunteered after consent of their parents. Saliva samples were collected within 2 days after birth and then after 1, 3, and 6 months. A saliva sample from the mothers was obtained 6 months after delivery. The parents were asked to complete a questionnaire on socioeconomic factors, lifestyle, and hygiene at baseline and throughout the study period. All samples were analyzed with 13 pre-determined bacterial probes using checkerboard DNA-DNA hybridization. The groups were balanced at baseline concerning all relevant background factors. Gram-positive streptococci (S. mitis, S. salivarius) displayed the highest counts in both groups but a greater diversity was observed in the vaginally delivered group. A. naeslundi, A. odontolytics, F. nucleatum and L. salivarius were only detected among the vaginally delivered infants. The prevalence of S. sanguinis, S. gordoni, R. denticariosa, and B. dentinum increased by age in both groups but the prevalence was significantly lower in the C-section group (p < 0.05). There was a link between the mothers and their offspring's concerning the salivary microbial profile. The microbial composition in saliva differs by the mode of delivery during the first six months of life.

  2. Skin Preparation for Prevention of Surgical Site Infection After Cesarean Delivery: A Randomized Controlled Trial.

    Science.gov (United States)

    Ngai, Ivan M; Van Arsdale, Anne; Govindappagari, Shravya; Judge, Nancy E; Neto, Nicole K; Bernstein, Jeffrey; Bernstein, Peter S; Garry, David J

    2015-12-01

    To compare chlorhexidine with alcohol, povidone-iodine with alcohol, and both applied sequentially to estimate their relative effectiveness in prevention of surgical site infections after cesarean delivery. Women undergoing nonemergent cesarean birth at greater than 37 0/7 weeks of gestation were randomly allocated to one of three antiseptic skin preparations: povidone-iodine with alcohol, chlorhexidine with alcohol, or the sequential combination of both solutions. The primary outcome was surgical site infection reported within the first 30 days postpartum. Based on a surgical site infection rate of 12%, an anticipated 50% reduction for the combination group relative to either single skin preparation group, with a power of 0.90 and an α of 0.05, 430 women per group were needed to detect a difference. From January 2013 to July 2014, 1,404 women were randomly assigned to one of three groups: povidone-iodine with alcohol (n=463), chlorhexidine with alcohol (n=474), or both (n=467). The groups were similar with respect to demographics, medical disorders, indication for cesarean delivery, operative time, and blood loss. The overall rate of surgical site infection-4.3%-was lower than anticipated. The skin preparation groups had similar surgical site infection rates: povidone-iodine 4.6%, chlorhexidine with alcohol 4.5%, and sequential 3.9% (P=.85). The skin preparation techniques resulted in similar rates of surgical site infections. Our study provides no support for any particular method of skin preparation before cesarean delivery. ClinicalTrials.gov, www.clinicaltrials.gov, NCT01870583. I.

  3. The effects of mode of delivery and sex of newborn on placental morphology in control and diabetic pregnancies

    DEFF Research Database (Denmark)

    Mayhew, T M; Sørensen, Flemming Brandt; Klebe, J G

    1993-01-01

    Placentae from control and diabetic subjects were analysed using stereological techniques in order to assess the effects of mode of delivery (vaginal versus caesarean) and sex of neonate on parenchymal morphology. Effects were assessed using indices of peripheral villous and fetal capillary growth...... of glucose and glycated haemoglobin levels. Neonatal and placental weights were recorded and placentae sampled in a systematic random fashion. Fields of view on formalin-fixed, paraffin-embedded sections were analysed to obtain estimates of volumes, surface areas, lengths and diffusion (harmonic mean...

  4. A strategy for photothermal conversion of polymeric nanoparticles by polyaniline for smart control of targeted drug delivery

    Science.gov (United States)

    You, Chaoqun; Wu, Hongshuai; Wang, Mingxin; Wang, Senlin; Shi, Tianyi; Luo, Yanghui; Sun, Baiwang; Zhang, Xiangyang; Zhu, Jin

    2017-04-01

    The near-infrared (NIR)-mediated novel strategy to control the drug release from nanocarriers has developed rapidly in recent decades. Polyaniline as a non-cytotoxic and electroactive material for studying cellular proliferation has attracted great attention in recent years. In the present work, polyaniline-mediated polymeric nanoparticles were developed to target the delivery of cisplatin and release it in a controllable way. The prepared polyaniline nanoparticles displayed a size of 90 ± 1.0 nm, a favorable morphology in water, and could be targeted to tumors through the high affinity between trastuzumab and the overexpressed Her2 in tumor cells. In addition, the developed nanoparticles demonstrated exciting photothermal conversion efficiency induced by NIR light and achieved significant cell inhibition efficiency (93.97%) in vitro when exposed to an 808 nm NIR laser with the power of 1.54 W for 5 min. Therefore, the developed external control release delivery system with excellent specificity and high cytotoxicity exhibited great potential in cell research and our research demonstrated that the polyaniline also has potential in the application of photothermal conversion in biomedicine.

  5. Finite-time generalized function matrix projective lag synchronization of coupled dynamical networks with different dimensions via the double power function nonlinear feedback control method

    International Nuclear Information System (INIS)

    Dai, Hao; Si, Gangquan; Jia, Lixin; Zhang, Yanbin

    2014-01-01

    This paper investigates the problem of finite-time generalized function matrix projective lag synchronization between two different coupled dynamical networks with different dimensions of network nodes. The double power function nonlinear feedback control method is proposed in this paper to guarantee that the state trajectories of the response network converge to the state trajectories of the drive network according to a function matrix in a given finite time. Furthermore, in comparison with the traditional nonlinear feedback control method, the new method improves the synchronization efficiency, and shortens the finite synchronization time. Numerical simulation results are presented to illustrate the effectiveness of this method. (papers)

  6. Analysis of structure of hyperfine poly(3-hydroxybutyrate) fibers (PHB) for controlled drug delivery

    Science.gov (United States)

    Olkhov, A. A.; Kosenko, R. Yu; Markin, V. S.; Zykova, A. K.; Pantyukhov, P. V.; Karpova, S. G.; Iordanskii, A. L.

    2017-12-01

    Hyperfine fibers based on biodegradable poly (3-hydroxybutyrate) with encapsulated drug substance (dipyridamol) were obtained by using electrospinning method. Addition of dipyridamol has a significant effect on geometrical shape and structure of microfibers as well as total porosity of fibrous material. Observation of fibers using scanning electron microscopy (SEM) method showed that without or at lower dipyridamol content (drug desorption from fibrous matrix was presented. In current work it was showed that the rate-limiting stage of transport was the diffusion of dipyridamol in the bulk of cylindrical fibers.

  7. Investigation of novel superparamagnetic Ni0.5Zn0.5Fe2O4@albumen nanoparticles for controlled delivery of anticancer drug

    Science.gov (United States)

    Qasim, Mohd; Asghar, Khushnuma; Dharmapuri, Gangappa; Das, D.

    2017-09-01

    In the present work, multifunctional Ni0.5Zn0.5Fe2O4@albumen (NZF@Alb) and doxorubicin-loaded Ni0.5Zn0.5Fe2O4@albumen (NZF@Alb-Dox) core-shell nanoparticles have been prepared by a green and simple method using inexpensive chicken egg albumen and have been characterized for different physiochemical properties. The structural, morphological, thermal, and magnetic properties of the prepared nanoparticles have been investigated by an x-ray diffractometer, high-resolution transmission electron microscopy (HRTEM), field emission scanning electron microscopy, Fourier-transformed infrared, thermogravimetric analysis, and vibrating sample magnetometer techniques. Superparamagnetic Ni0.5Zn0.5Fe2O4 nanoparticles (NZF NPs) with the mean size ˜20 nm were coated with albumen matrix by an ultrasonication process. Inverse fast Fourier transform-assisted HRTEM micrographs and FTIR analysis revealed the coating of amorphous albumen on crystalline NZF NPs. NZF@Alb and NZF@Alb-Dox NPs have the mean size (D50) of ˜100 nm, good stability, and magnetic controllability. Magnetic measurements (field (H)-dependent magnetization (M)) show all samples to be super-paramagnetic in nature. Biocompatibilities of the NZF and NZF@Alb NPs were confirmed by in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay against RAW 264.7 cells. NZF@Alb NPs have been found to be more biocompatible than bare NZF. In Vitro Dox release behavior from NZF@Alb-Dox NPs has been studied at pH 7.4 and 5, and a sustained and pH-dependent drug release profile were observed. In vitro cytotoxicity or anticancer activity of the blank NZF@Alb NPs, free Dox, and NZF@Alb-Dox NPs against HeLa cells (cancer cell line) were also examined by MTT assay. The obtained results suggest that this scalable egg-albumen-based magnetic nanoformulation is suitable for targeted drug delivery applications. Thus, the present study could be extremely useful for the advancement of albumin-based nanocarrier design and

  8. Smart Drug Delivery Systems in Cancer Therapy.

    Science.gov (United States)

    Unsoy, Gozde; Gunduz, Ufuk

    2018-02-08

    Smart nanocarriers have been designed for tissue-specific targeted drug delivery, sustained or triggered drug release and co-delivery of synergistic drug combinations to develop safer and more efficient therapeutics. Advances in drug delivery systems provide reduced side effects, longer circulation half-life and improved pharmacokinetics. Smart drug delivery systems have been achieved successfully in the case of cancer. These nanocarriers can serve as an intelligent system by considering the differences of tumor microenvironment from healthy tissue, such as low pH, low oxygen level, or high enzymatic activity of matrix metalloproteinases. The performance of anti-cancer agents used in cancer diagnosis and therapy is improved by enhanced cellular internalization of smart nanocarriers and controlled drug release. Here, we review targeting, cellular internalization; controlled drug release and toxicity of smart drug delivery systems. We are also emphasizing the stimulus responsive controlled drug release from smart nanocarriers. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  9. A barrier retractor to reduce surgical site infections and wound disruptions in obese patients undergoing cesarean delivery: a randomized controlled trial.

    Science.gov (United States)

    Scolari Childress, Katherine M; Gavard, Jeffrey A; Ward, Donald G; Berger, Kinley; Gross, Gilad A

    2016-02-01

    Surgical site infections (SSIs) are an important cause of morbidity following cesarean delivery, particularly in obese patients. Methods to reduce SSIs after cesarean delivery would have an important impact in obese obstetric patients. The purpose of this study was to determine whether the Alexis O cesarean delivery retractor, a barrier self-retaining retractor, reduces SSIs and wound disruptions in obese patients undergoing cesarean delivery. This was a randomized controlled trial of obese women (body mass index ≥ 30 kg/m(2)) undergoing nonemergent cesarean delivery. Patients were randomized to the treatment group (using the Alexis O cesarean delivery retractor) or to the control group (using conventional handheld retractors). The primary outcome was SSI or wound disruption during the 30 day postoperative period. Secondary outcomes included operative time, estimated blood loss, change in hemoglobin, antiemetic use, length of postoperative hospital stay, hospital readmission, and other postoperative complications. A total of 301 patients were enrolled in the study. One hundred forty-four patients were randomized to the treatment group and 157 to the control group. Baseline characteristics and indications for cesarean delivery were similar between the 2 groups. Median body mass index was 40.1 kg/m(2). There were no significant differences between the treatment and the control group in the primary outcome of SSI or wound disruption rates at the 30 day assessment (20.6% vs 17.6%, P = .62), during the postoperative inpatient hospitalization or at the 1-2 week postoperative visit. There were also no differences in the primary outcome when adjusting for obesity class or thickness of the subcuticular layer. Patients in the treatment group had lower rates of uterine exteriorization (54.3% vs 87.3%, P cesarean delivery deliveries did not decrease SSI or wound disruption rates in an obese population. Its use as a retractor should be left to the discretion of the surgeon

  10. Transcutaneous electrical nerve stimulation (TENS) for pain control after vaginal delivery and cesarean section.

    Science.gov (United States)

    Kayman-Kose, Seda; Arioz, Dagistan Tolga; Toktas, Hasan; Koken, Gulengul; Kanat-Pektas, Mine; Kose, Mesut; Yilmazer, Mehmet

    2014-10-01

    The present study aims to determine the efficiency and reliability of transcutaneous electrical nerve stimulation (TENS) in the management of pain related with uterine contractions after vaginal delivery and the pain related with both abdominal incision uterine contractions after cesarean section. A hundred healthy women who underwent cesarean section under general anesthesia were randomly assigned to the placebo group (Group 1) or the TENS group (Group 2), while 100 women who delivered by vaginal route without episiotomy were randomized into the placebo group (Group 3) or the TENS group (Group 4). The patients in Group 2 had statistically lower visual analog scale (VAS) and verbal numerical scale (VNS) scores than the patients in Group 1 (p TENS (p = 0.006). The need for analgesics at the eighth hour of vaginal delivery was statistically similar in the patients who were treated with TENS and the patients who received placebo (p = 0.830). TENS is an effective, reliable, practical and easily available modality of treatment for postpartum pain.

  11. A self-adherent, bullet-shaped microneedle patch for controlled transdermal delivery of insulin.

    Science.gov (United States)

    Seong, Keum-Yong; Seo, Min-Soo; Hwang, Dae Youn; O'Cearbhaill, Eoin D; Sreenan, Seamus; Karp, Jeffrey M; Yang, Seung Yun

    2017-11-10

    Proteins are important biologic therapeutics used for the treatment of various diseases. However, owing to low bioavailability and poor skin permeability, transdermal delivery of protein therapeutics poses a significant challenge. Here, we present a new approach for transdermal protein delivery using bullet-shaped double-layered microneedle (MN) arrays with water-swellable tips. This design enabled the MNs to mechanically interlock with soft tissues by selective distal swelling after skin insertion. Additionally, prolonged release of loaded proteins by passive diffusion through the swollen tips was obtained. The bullet-shaped MNs provided an optimal geometry for mechanical interlocking, thereby achieving significant adhesion strength (~1.6Ncm -2 ) with rat skin. By harnessing the MN's reversible swelling/deswelling property, insulin, a model protein drug, was loaded in the swellable tips using a mild drop/dry procedure. The insulin-loaded MN patch released 60% of insulin when immersed in saline over the course of 12h and approximately 70% of the released insulin appeared to have preserved structural integrity. An in vivo pilot study showed a prolonged release of insulin from swellable MN patches, leading to a gradual decrease in blood glucose levels. This self-adherent transdermal MN platform can be applied to a variety of protein drugs requiring sustained release kinetics. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Pickering emulsions stabilized by biodegradable block copolymer micelles for controlled topical drug delivery.

    Science.gov (United States)

    Laredj-Bourezg, Faiza; Bolzinger, Marie-Alexandrine; Pelletier, Jocelyne; Chevalier, Yves

    2017-10-05

    Surfactant-free biocompatible and biodegradable Pickering emulsions were investigated as vehicles for skin delivery of hydrophobic drugs. O/w emulsions of medium-chain triglyceride (MCT) oil droplets loaded with all-trans retinol as a model hydrophobic drug were stabilized by block copolymer nanoparticles: either poly(lactide)-block-poly(ethylene glycol) (PLA-b-PEG) or poly(caprolactone)-block-poly(ethylene glycol) (PCL-b-PEG). Those innovative emulsions were prepared using two different processes allowing drug loading either inside oil droplets or inside both oil droplets and non-adsorbed block copolymer nanoparticles. Skin absorption of retinol was investigated in vitro on pig skin biopsies using the Franz cell method. Supplementary experiments by confocal fluorescence microscopy allowed the visualization of skin absorption of the Nile Red dye on histological sections. Retinol and Nile Red absorption experiments showed the large accumulation of hydrophobic drugs in the stratum corneum for the Pickering emulsions compared to the surfactant-based emulsion and an oil solution. Loading drug inside both oil droplets and block copolymer nanoparticles enhanced again skin absorption of drugs, which was ascribed to the supplementary contribution of free block copolymer nanoparticles loaded with drug. Such effect allowed tuning drug delivery to skin over a wide range by means of a suitable selection of either the formulation or the drug loading process. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Boswellia gum resin/chitosan polymer composites: Controlled delivery vehicles for aceclofenac.

    Science.gov (United States)

    Jana, Sougata; Laha, Bibek; Maiti, Sabyasachi

    2015-01-01

    This study was undertaken to evaluate the effect of Boswellia gum resin on the properties of glutaraldehyde (GA) crosslinked chitosan polymer composites and their potential as oral delivery vehicles for a non-steroidal anti-inflammatory drug, aceclofenac. The incorporation of resinous material caused a significant improvement in drug entrapment efficiency (∼40%) of the polymer composites. Fourier transform infrared (FTIR) spectroscopic analysis confirmed the formation of chitosan-gum resin composites and did not show any evidence of drug-polymer chemical interaction. Field emission scanning electron microscopy (FE-SEM) suggested the formation of particulate polymer composites up to chitosan:gum resin mass ratio of 1:3. Only 8-17% drug was released into HCl solution (pH 1.2) in 2h. The drug release rate of polymer composites was faster in phosphate buffer solution (pH 6.8). The composites released ∼60-68% drug load in 7h. In same duration, the drug release rate suddenly boosted up to 92% as the concentration of gum resin in the composites was raised to 80%. The drug release mechanism deviated from non-Fickian to case-II type with increasing resin concentration in the composites. Hence, GA-treated Boswellia resin-chitosan composites could be considered as alternative vehicles for oral delivery of aceclofenac. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Effects of Reiki on Post-cesarean Delivery Pain, Anxiety, and Hemodynamic Parameters: A Randomized, Controlled Clinical Trial.

    Science.gov (United States)

    Midilli, Tulay Sagkal; Eser, Ismet

    2015-06-01

    The aim of this study was to investigate the effect of Reiki on pain, anxiety, and hemodynamic parameters on postoperative days 1 and 2 in patients who had undergone cesarean delivery. The design of this study was a randomized, controlled clinical trial. The study took place between February and July 2011 in the Obstetrical Unit at Odemis Public Hospital in Izmir, Turkey. Ninety patients equalized by age and number of births were randomly assigned to either a Reiki group or a control group (a rest without treatment). Treatment applied to both groups in the first 24 and 48 hours after delivery for a total of 30 minutes to 10 identified regions of the body for 3 minutes each. Reiki was applied for 2 days once a day (in the first 24 and 48 hours) within 4-8 hours of the administration of standard analgesic, which was administered intravenously by a nurse. A visual analog scale and the State Anxiety Inventory were used to measure pain and anxiety. Hemodynamic parameters, including blood pressure (systolic and diastolic), pulse and breathing rates, and analgesic requirements also were recorded. Statistically significant differences in pain intensity (p = .000), anxiety value (p = .000), and breathing rate (p = .000) measured over time were found between the two groups. There was a statistically significant difference between the two groups in the time (p = .000) and number (p = .000) of analgesics needed after Reiki application and a rest without treatment. Results showed that Reiki application reduced the intensity of pain, the value of anxiety, and the breathing rate, as well as the need for and number of analgesics. However, it did not affect blood pressure or pulse rate. Reiki application as a nursing intervention is recommended as a pain and anxiety-relieving method in women after cesarean delivery. Copyright © 2015 American Society for Pain Management Nursing. Published by Elsevier Inc. All rights reserved.

  15. Fabrication and characterization of a rapid prototyped tissue engineering scaffold with embedded multicomponent matrix for controlled drug release

    DEFF Research Database (Denmark)

    Chen, Muwan; Le, Dang Qs; Hein, San

    2012-01-01

    scaffold was embedded with a porous matrix composed of chitosan, nanoclay, and β-tricalcium phosphate by freeze-drying. This composite scaffold was evaluated on its ability to deliver an anthracycline antibiotic and to promote formation of mineralized matrix in vitro. Scanning electronic microscopy...

  16. Probing suitable therapeutic nanoparticles for controlled drug delivery and diagnostic reproductive health biomarker development

    Energy Technology Data Exchange (ETDEWEB)

    Jha, Rakhi [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); National Institute of Animal Welfare, Ministry of Environment, Forest and Climate Change, Faridabad, Haryana 121 004 (India); Jha, Pradeep K., E-mail: jha.rk.pk@gmail.com [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); Gupta, Santosh; Bhuvaneshwaran, S.P. [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India); Hossain, Maidul [Department of Chemistry & Chemical Technology, Vidyasagar University, Midnapore 721102 (India); Guha, Sujoy K. [School of Medical Science and Technology, Indian Institute of Technology Kharagpur, Kharagpur 721 302 (India)

    2016-04-01

    Nanomaterial mediated drug delivery represents a highly promising technique while its selectivity for reproductive healthcare application still remains a challenge. Since the delicate structure and functional role of reproductive tissue and gametes require the use of biocompatible nanomedicine/devices that do not affect fertility or the development of resulting offspring, this paper reports an intercomparative study of human spermatozoa interaction with three different nanoparticles (NPs) namely; iron oxide (Fe{sub 3}O{sub 4)}, multiwalled carbon nanotubes (MWCNT) and graphene platelet nanopowder (GPN) to probe their suitability for drug delivery carrier and biomarker development purposes. ATR–FTIR results revealed that the sperm cell interaction with GPN had maximum amide I absorption for cell proteins and C=O stretching of the peptide backbone at the band around 1657 cm{sup −1} followed by iron oxide NPs whereas MWCNT had no absorption. These results showed that GPN followed by iron oxide NPs got maximally entrapped by cell membrane protein with maximum disruption but MWCNT exhibited less entrapment but significantly higher internalization which was further validated by morphological analysis of these cell NP interaction by SEM, HRTEM and fluorescence microscopy. The uptake kinetics and penetration mechanism of NPs were examined with isothermal titration calorimetry (ITC). Interestingly, ITC results confirmed ATR–FTIR and morphological observations that the binding of GPN and Fe{sub 3}O{sub 4} NPs with cell was exothermic and their bindings were favored by both negative enthalpy and positive entropy whereas in the case of MWCNT it was endothermic supported by unfavorable positive enthalpy and a favorable entropy change. Hence, it was evident that MWCNT had better internalization efficiency without disrupting the sperm lipid membrane compared to Fe{sub 3}O{sub 4} and GPN NPs. Therefore, this work proposes CNT as promising means. - Highlights: • Biophysical

  17. Risk of macular degeneration affected by polymorphisms in Matrix metalloproteinase-2: A case-control study in Chinese Han population.

    Science.gov (United States)

    Cheng, Jie; Hao, Xiaolin; Zhang, Zhongchen

    2017-11-01

    The purpose of this study was to investigate the correlation of single nucleotide polymorphisms (SNPs) in Matrix metalloproteinase -2 (MMP-2) gene and the risk of age-related macular degeneration (AMD) in Chinese Han population.A total of 126 AMD patients and 141 healthy controls participated in this study. Genotypes of MMP-2 gene polymorphisms were identified by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). χtest was used to detect the differences of genotypes and alleles frequencies between case and control groups. Relative risk of AMD was evaluated by odds ratios (ORs) with 95% confidence intervals (CIs).Distribution of variant allele carriers (computed tomography + TT genotypes) of MMP-2 gene rs243865 SNP was significantly different between case and control groups, and might act as protective factors for the onset of AMD (P = .044, OR = 0.583, 95% CI = 0.344-0.987). Nevertheless, the T allele might reduce the AMD risk (P = .030, OR = 0.611, 95% CI = 0.390-0.956). However, no significant association existed between rs243865 and AMD risk in the subgroup analysis based on age. GA + AA genotypes of rs243866 SNP may associate with a decreased risk of AMD in the age≤65 years subgroup (P = .028, OR = 0.399, 95% CI = 0.174-0.915).MMP-2 gene rs243865 and rs243866 SNPs associated with the risk of AMD. Further studies should be performed to confirm the results. Copyright © 2017 The Authors. Published by Wolters Kluwer Health, Inc. All rights reserved.

  18. A gel aspiration-ejection system for the controlled production and delivery of injectable dense collagen scaffolds

    International Nuclear Information System (INIS)

    Kamranpour, Neysan O; Miri, Amir K; James-Bhasin, Mark; Nazhat, Showan N

    2016-01-01

    A gel aspiration-ejection (GAE) system has been developed for the advanced production and delivery of injectable dense collagen (I-DC) gels of unique collagen fibrillar densities (CFDs). Through the creation of negative pressure, GAE aspirates prefabricated highly hydrated collagen gels into a needle, simultaneously inducing compaction and meso-scale anisotropy (i.e., fibrillar alignment) on the gels, and by subsequent reversal of the pressure, I-DC gels can be controllably ejected. The system generates I-DC gels with CFDs ranging from 5 to 32 wt%, controlling the initial scaffold microstructure, anisotropy, hydraulic permeability, and mechanical properties. These features could potentially enable the minimally invasive delivery of more stable hydrogels. The viability, metabolic activity, and differentiation of seeded mesenchymal stem cells (MSCs) was investigated in the I-DC gels of distinct CFDs and extents of anisotropy produced through two different gauge needles. MSC osteoblastic differentiation was found to be relatively accelerated in I-DC gels that combined physiologically relevant CFDs and increased fibrillar alignment. The ability to not only support homogenous cell seeding, but also to direct and accelerate their differentiation through tissue-equivalent anisotropy, creates numerous opportunities in regenerative medicine. (paper)

  19. Periodic Mesoporous Organosilica Nanoparticles with Controlled Morphologies and High Drug/Dye Loadings for Multicargo Delivery in Cancer Cells

    KAUST Repository

    Croissant, Jonas G.

    2016-06-01

    Despite the worldwide interest generated by periodic mesoporous organosilica (PMO) bulk materials, the design of PMO nanomaterials with controlled morphology remains largely unexplored and their properties unknown. In this work, we describe the first study of PMO nanoparticles (NPs) based on meta-phenylene bridges, and we conducted a comparative structure–property relationship investigation with para-phenylene-bridged PMO NPs. Our findings indicate that the change of the isomer drastically affects the structure, morphology, size, porosity and thermal stability of PMO materials. We observed a much higher porosity and thermal stability of the para-based PMO which was likely due to a higher molecular periodicity. Additionally, the para isomer could generate multipodal NPs at very low stirring speed and upon this discovery we designed a phenylene–ethylene bridged PMO with a controlled Janus morphology. Unprecedentedly high payloads could be obtained from 40 to 110 wt % regardless of the organic bridge of PMOs. Finally, we demonstrate for the first time the co-delivery of two cargos by PMO NPs. Importantly, the cargo stability in PMOs did not require the capping of the pores, unlike pure silica, and the delivery could be autonomously triggered in cancer cells by acidic pH with nearly 70 % cell killing. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  20. Kinetic Degradation and Controlled Drug Delivery System Studies for Sensitive Hydrogels Prepared by Gamma Irradiation

    International Nuclear Information System (INIS)

    Eid, M.; El-Arnaouty, M.B.

    2008-01-01

    Ternary mixtures of N-vinyle-2-pyrrolidone(NVP ), itaconic acid (IA) and gelatin (G) were gamma irradiated to prepared poly(NVP/IA/G) hydrogels. The equilibrium kinetic swelling, drug release behavior, Scan Electron Microscope (SEM) and the swelling-degradation kinetics were studied. Both the diffusion exponent and the diffusion coefficient increase with increasing content of (IA). Also, the swelling behavior of copolymer hydrogels in response to ph value of the external media was studied, it is noted that the highest swelling values at ph 4. The in vitro drug release behavior of these hydrogels was examined by quantification analysis with a UV/VIS spectrophotometers. Chlorpromazine hydrochloride was loaded into dried hydrogels to investigate the stimuli-sensitive property at the specific ph. The release studies show that the highest value of release was at ph 4 which can be used for drug delivery system

  1. Calorimetric Study of Mesoporous SBA-15 Modified for Controlled Valproic Acid Delivery

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2013-01-01

    Full Text Available SBA-15 ordered mesoporous silica functionalized with (3-aminopropyltriethoxysilane (APTES was used as the carrier for anticonvulsant drug 2-propylpentanoic acid (valproic acid. The surface of SBA-15 containing free silanol groups was modified with 3-aminopropyltriethoxysilane via postsynthetic reaction. Functionalization of the carrier with basic aminopropyl groups resulted in an ionic interaction with acidic valproic acid. The samples of carriers and carrier-drug complexes were characterized by elemental analysis, N2 adsorption, FTIR, and UV spectroscopy. The adsorption of valproic acid on modified mesoporous matrix was proportional to the amount of introduced aminopropyl groups. A thermodynamic study with isothermal titration calorimetry (ITC was made to characterize the modification and encapsulation of SBA-15 with APTES and valproic acid, respectively. The maximum content of deposited drug in modified SBA-15 was close to 30 wt.%. Tests performed in acidic solution (pH 2.0 showed the best pharmaceutical availability.

  2. Preparation of explosive nanoparticles in a porous chromium(III) oxide matrix: a first attempt to control the reactivity of explosives

    Energy Technology Data Exchange (ETDEWEB)

    Comet, M; Siegert, B; Pichot, V; Gibot, P; Spitzer, D [Laboratoire ISL/CNRS ' Nanomateriaux pour les Systemes Sous Sollicitations Extremes' (NS3E), FRE 3026, French-German Research Institute of Saint-Louis (ISL), 5 rue du General Cassagnou, 68301 Saint-Louis (France)], E-mail: comet@isl.tm.fr

    2008-07-16

    This paper reports the first attempt to control the combustion and the detonation properties of a high explosive through its structure. A porous chromium(III) oxide matrix produced by the combustion of ammonium dichromate was infiltrated by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The structure of the Cr{sub 2}O{sub 3} matrix was studied by both scanning and transmission electron microscopy (SEM, TEM); the Cr{sub 2}O{sub 3}/RDX nanocomposites were characterized by nitrogen adsorption. A mathematical model based on these techniques was used to demonstrate that the Cr{sub 2}O{sub 3} matrix encloses and stabilizes RDX particles at the nanoscale. The decomposition process of the nanocomposites was investigated by atomic force microscopy (AFM). The reactivity and sensitivity of the nanocomposites were studied by impact and friction tests, differential scanning calorimetry (DSC), time-resolved cinematography and detonation experiments, and were correlated with their structure. The size of RDX nanoparticles and their distribution in the Cr{sub 2}O{sub 3} matrix have an important influence on their reactivity. The reactive properties of nanostructured RDX differ significantly from those of classical micron-sized RDX. For instance, the melting point disappears and the decomposition temperature is significantly lowered. The quantization of the explosive particles in the Cr{sub 2}O{sub 3} matrix decreases the sensitivity to mechanical stress and allows controlling the decomposition mode-i.e. combustion versus detonation.

  3. Preparation of explosive nanoparticles in a porous chromium(III) oxide matrix: a first attempt to control the reactivity of explosives

    International Nuclear Information System (INIS)

    Comet, M; Siegert, B; Pichot, V; Gibot, P; Spitzer, D

    2008-01-01

    This paper reports the first attempt to control the combustion and the detonation properties of a high explosive through its structure. A porous chromium(III) oxide matrix produced by the combustion of ammonium dichromate was infiltrated by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The structure of the Cr 2 O 3 matrix was studied by both scanning and transmission electron microscopy (SEM, TEM); the Cr 2 O 3 /RDX nanocomposites were characterized by nitrogen adsorption. A mathematical model based on these techniques was used to demonstrate that the Cr 2 O 3 matrix encloses and stabilizes RDX particles at the nanoscale. The decomposition process of the nanocomposites was investigated by atomic force microscopy (AFM). The reactivity and sensitivity of the nanocomposites were studied by impact and friction tests, differential scanning calorimetry (DSC), time-resolved cinematography and detonation experiments, and were correlated with their structure. The size of RDX nanoparticles and their distribution in the Cr 2 O 3 matrix have an important influence on their reactivity. The reactive properties of nanostructured RDX differ significantly from those of classical micron-sized RDX. For instance, the melting point disappears and the decomposition temperature is significantly lowered. The quantization of the explosive particles in the Cr 2 O 3 matrix decreases the sensitivity to mechanical stress and allows controlling the decomposition mode-i.e. combustion versus detonation

  4. Formulation and in vitro evaluation of mucoadhesive controlled release matrix tablets of flurbiprofen using response surface methodology

    Directory of Open Access Journals (Sweden)

    Ikrima Khalid

    2014-09-01

    Full Text Available The objective of the current study was to formulate mucoadhesive controlled release matrix tablets of flurbiprofen and to optimize its drug release profile and bioadhesion using response surface methodology. Tablets were prepared via a direct compression technique and evaluated for in vitro dissolution parameters and bioadhesive strength. A central composite design for two factors at five levels each was employed for the study. Carbopol 934 and sodium carboxymethylcellulose were taken as independent variables. Fourier transform infrared (FTIR spectroscopy studies were performed to observe the stability of the drug during direct compression and to check for a drug-polymer interaction. Various kinetic models were applied to evaluate drug release from the polymers. Contour and response surface plots were also drawn to portray the relationship between the independent and response variables. Mucoadhesive tablets of flurbiprofen exhibited non-Fickian drug release kinetics extending towards zero-order, with some formulations (F3, F8, and F9 reaching super case II transport, as the value of the release rate exponent (n varied between 0.584 and 1.104. Polynomial mathematical models, generated for various response variables, were found to be statistically significant (P<0.05. The study also helped to find the drug's optimum formulation with excellent bioadhesive strength. Suitable combinations of two polymers provided adequate release profile, while carbopol 934 produced more bioadhesion.

  5. Evaluation of Ocimum basilicum L. seed mucilage as rate controlling matrix for sustained release of propranolol HCl

    Directory of Open Access Journals (Sweden)

    Majid Saeedi

    2015-01-01

    Full Text Available Polysaccharide mucilage derived from the seeds of Ocimum basilicum L. (family Lamiaceae was investigated for use in matrix formulations containing propranolol hydrochloride. Basil mucilage was extracted and several tablets were formulated. The effect of mucilage on drug release rate was evaluated in comparison with tablets containing two kinds of hydroxypropyl methylcellulose (HPMC K4M and HPMC K100M as standard polymer. The release data were fitted to several models for kinetic evaluation. The results showed that hardness decreased and friability of tablets increased as the concentration of mucilage increased. The rate of release of propranolol HCl from O. basilicm mucilage matrices was mainly controlled by the drug: mucilage ratio. Drug release was slower from the HPMC K4M and HPMCK100M containing tablets compared to the mucilage containing matrices than the drug release from matrices containing O. basilicum seed mucilage in similar ratios.  Formulations containing O. basilicm mucilage were found to exhibit suitable release pattern. The results of kinetic analysis showed that in tablets containing O. basilicm mucilage the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that, as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets.

  6. Evaluation of Plantago major L. seed mucilage as a rate controlling matrix for sustained release of propranolol hydrochloride.

    Science.gov (United States)

    Saeedi, Majid; Morteza-Semnani, Katayoun; Sagheb-Doust, Mehdi

    2013-03-01

    Polysaccharide mucilage derived from the seeds of Plantago major L. (family Plantaginaceae) was investigated for use in matrix formulations containing propranolol hydrochloride. HPMC K4M and tragacanth were used as standards for comparison. The hardness, tensile strength, and friability of tablets increased as the concentration of mucilage increased, indicating good compactibility of mucilage powders. The rate of release of propranolol hydrochloride from P. major mucilage matrices was mainly controlled by the drug/mucilage ratio. Formulations containing P. major mucilage were found to exhibit a release rate comparable to HPMC containing matrices at a lower drug/polymer ratio (drug/HPMC 2:1). These results demonstrated that P. major mucilage is a better release retardant compared to tragacanth at an equivalent content. The results of kinetic analysis showed that in F3 (containing 1:2 drug/mucilage) the highest correlation coefficient was achieved with the zero order model. The swelling and erosion studies revealed that as the proportion of mucilage in tablets was increased, there was a corresponding increase in percent swelling and a decrease in percent erosion of tablets. The DSC and FT-IR studies showed that no formation of complex between the drug and mucilage or changes in crystallinity of the drug had occurred.

  7. Effect of Oral Lipid Matrix Supplement on Fat Absorption in Cystic Fibrosis: A Randomized Placebo-Controlled Trial

    Science.gov (United States)

    Stallings, Virginia A.; Schall, Joan I.; Maqbool, Asim; Mascarenhas, Maria R.; Alshaikh, Belal N.; Dougherty, Kelly A.; Hommel, Kevin; Ryan, Jamie; Elci, Okan U.; Shaw, Walter A.

    2016-01-01

    Pancreatic enzyme therapy does not normalize dietary fat absorption in patients with cystic fibrosis (CF) and pancreatic insufficiency (PI). Efficacy of LYM-X-SORBTM (LXS), an easily absorbable lipid matrix that enhances fat absorption was evaluated in a 12-month randomized, double-blinded, placebo-controlled trial with plasma fatty acids (FA), and coefficient of fat absorption (CFA) outcomes. 110 subjects (age 10.4±3.0 y) were randomized. Total FA increased with LXS at 3 and 12 months (+1.58; +1.14 mmol/L) and not with placebo (P=0.046). With LXS, linoleic acid (LA) increased at 3 and 12 months (+298; +175 nmol/mL, P≤0.046), with a 6% increase in CFA (P<0.01). LA increase was significant in LXS vs. placebo (445 vs. 42 nmol/mL, P= 0.038). Increased FA and LA predicted increased BMI Z scores. In summary, LXS treatment improved dietary fat absorption compared to placebo as indicated by plasma FA and LA and was associated with better growth status. PMID:27050056

  8. Internal service quality by integrated approach Performance Control Matrix (PCM & Importance-Satisfaction Model (Studied in Yazd Regional Power Company

    Directory of Open Access Journals (Sweden)

    Saeid Peirow

    2016-02-01

    Full Text Available Today, the internal service quality as one of the most important factors affecting the recruitment and retention of staff is considered. The present study sought to examine the internal service quality of Yazd Regional Electric, finally, select appropriate strategies to improve the quality of local services in the organization. The application of this study is base on survey method.Data were collected from questionnaires to evaluate the 26 components of internal service quality of Yazd Regional Electric, has been used. Research community is the staff of the organisation.Also, the sample size, the initial questionnaire was distributed according to Cochran's formula is calculated.In order to analyze research data, the model is important - satisfaction and performance control matrix to identify those components that are used need to be improved.Also, in order to prioritize measures to improve employee satisfaction index is used. Data analysis using above tools show, 8 criteria are in improvment area. So, these criteria are prioritized with ESI.

  9. The Efficacy of Postoperative Wound Infusion with Bupivacaine for Pain Control after Cesarean Delivery: Randomized Double Blind Clinical Trial

    Directory of Open Access Journals (Sweden)

    Azin Alavi

    2007-06-01

    Full Text Available Objective: This study investigated the efficacy of bupivacaine wound infusion for pain control and opioid sparing effect after cesarean delivery.Materials and methods: We conducted a randomized double blind, placebo controlled clinical trial on 60 parturients undergoing cesarean section at a university hospital in Tehran. Patients were randomized to receive a pump infusion system that was filled with either 0.25% bupivacaine or equal volume of distilled water. A catheter was placed above the fascia and connected to electronic pump for 24 hours. Postoperative analog pain scores and morphine consumption were assessed at 6, 12 and 24 hours. Also time interval to first ambulation, length of hospitalization, complications and patient satisfaction were recorded. Data were analyzed using the SPSS software and P < 0.05 was considered statistically significant. Mann-Whitney u-test, student t-test and chi-square were used. Results: There were no differences in patient demographics and length of hospitalization and patient-generated resting pain scores between the two groups. Pain scores after coughing and leg raise during the first 6 postoperative hours were significantly less in the Bupivacaine group (P<0.001. The total dose of morphine consumption during the 24 hours study period was 2.5 ± 2.5 mg vs. 7.3 ± 2.7 mg for the bupivacaine and control groups, respectively (P<0.001. Compared with the control group, time to first ambulation was shorter in the bupivacaine group (11± 5h vs. 16 ± 4h (P< 0.01. Conclusion: Bupivacaine wound infusion was a simple and safe technique that provides effective analgesia and reduces morphine requirements after cesarean delivery.

  10. Can Intrapartum Cardiotocography Predict Uterine Rupture among Women with Prior Caesarean Delivery?: A Population Based Case-Control Study.

    Directory of Open Access Journals (Sweden)

    Malene M Andersen

    Full Text Available To compare cardiotocographic abnormalities recorded during labour in women with prior caesarean delivery (CD and complete uterine rupture with those recorded in controls with prior CD without uterine rupture.Women with complete uterine rupture during labour between 1997 and 2008 were identified in the Danish Medical Birth Registry (n = 181. Cases were validated by review of medical records and 53 cases with prior CD, trial of labour, available cardiotocogram (CTG and complete uterine rupture were included and compared with 43 controls with prior CD, trial of labour and available CTG. The CTG tracings were assessed by 19 independent experts divided into groups of three different experts for each tracing. The assessors were blinded to group, outcome and clinical data. They analyzed occurrence of defined abnormalities and classified the traces as normal, suspicious, pathological or pre-terminal according to international guidelines (FIGO.A pathological CTG during the first stage of labour was present in 77% of cases and in 53% of the controls (OR 2.58 [CI: 0.96-6.94] P = 0.066. Fetal tachycardia was more frequent in cases with uterine rupture (OR 2.50 [CI: 1.0-6.26] P = 0.053. Significantly more cases showed more than 10 severe variable decelerations compared with controls (OR 22 [CI: 1.54-314.2] P = 0.022. Uterine tachysystole was not correlated with the presence of uterine rupture.A pathological cardiotocogram should lead to particular attention on threatening uterine rupture but cannot be considered a strong predictor as it is common in all women with trial of labour after caesarean delivery.

  11. Screening and brief intervention delivery in the workplace to reduce alcohol-related harm: a pilot randomized controlled trial.

    Science.gov (United States)

    Watson, Hazel; Godfrey, Christine; McFadyen, Angus; McArthur, Katherine; Stevenson, Marisa; Holloway, Aisha

    2015-01-01

    To explore the feasibility and cost effectiveness of screening and delivery of a brief intervention for hazardous drinking employees. A pilot randomised controlled trial of a brief intervention delivered by an Occupational Health nurse versus no delivery of brief intervention (control group) conducted in a Local Authority Council (LCA) in the United Kingdom. Changes in quality of life and economic indicators were measured by the EQ-5D. 627 employees were screened of whom 163 (26.01%) fulfilled the inclusion criteria with a total of 57 (35%) agreeing to participate. No significant differences were found between the groups for baseline demographics or levels/patterns of alcohol consumption. A statistically significant effect was found in the mean AUDIT scores over time (F=8.96, p=0.004) but not for group (F=0.017, p=0.896), and no significant interaction was found (F=0.148, p=0.702). The cost of each intervention was calculated at £12.48, the difference in service costs was calculated at £344.50 per person; that is there was a net saving of health and other care costs in the intervention group compared to the control group. The QALYs fell in both intervention and control groups, the difference -0.002-(-0.010) yields a net advantage of the intervention of 0.008 QALYs. The main results from this pilot study suggest that alcohol brief interventions delivered in the workplace may offer the potential to reduce alcohol-related harm and save public sector resources. A fully powered multi-centre trial is warranted to contribute to the current evidence base and explore further the potential of alcohol brief interventions in the workplace. In a full trial the recruitment method may need to be re-considered. Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Design, fabrication and evaluation of two-dimensional to three-dimensional nanostructured ceramic/polymer composites for orthopedic regeneration and controlled drug delivery

    Science.gov (United States)

    Liu, Huinan

    Desirable cytocompatibility properties of nano-sized ceramics were combined with the tunable degradability and deformability of a select polymer (poly-lactide-co-glycolide, or PLGA) to optimize biological and mechanical properties for orthopedic tissue regeneration. Nanophase ceramics mimic the size scale of constituent components of natural bone and enhance the adsorption of proteins that mediate bone cell adhesion. Results have shown significantly promoted osteoblast (bone-forming cell) adhesion and long-term functions (alkaline phosphatase activity and calcium deposition) on nanophase ceramics compared to conventional (micron-scale) ceramics. Therefore, nano-titania particles were first dispersed in a model polymer (PLGA) matrix using sonication to imitate the nano-sized surface features and distribution of nano-ceramics in/on bone. Surface characteristics of the composites (such as topography, surface area and surface roughness) were studied. Importantly, results showed that osteoblast adhesion was the greatest when surface roughness values of the composites were closer to that of natural bone; this was mediated by controlling the dispersion of titania in PLGA. Moreover, this study demonstrated that the dispersion of nanophase titania in PLGA decreased the harmful acidic pH changes of PLGA as it degrades. From the perspective of mechanical properties, compared to agglomerated nano-titania in PLGA, well-dispersed nanophase titania in PLGA improved the tensile and compressive moduli and strength of these composites. In order to mimic the hierarchical structure of bone, a novel aerosol-based 3D printing technique was used to further fabricate nanostructured 3D ceramic/polymer composites. Osteoblast interactions with these 3D scaffolds provided evidence of an even further promoted bone cell infiltration into such 3D structures. Lastly, nanocomposites were used as novel drug delivery systems to promote bone growth. Specifically, a bone morphogenetic protein (BMP-7

  13. Delivery presentations

    Science.gov (United States)

    Pregnancy - delivery presentation; Labor - delivery presentation; Occiput posterior; Occiput anterior; Brow presentation ... The mother can walk, rock, and try different delivery positions during labor to help encourage the baby ...

  14. Automated MALDI Matrix Coating System for Multiple Tissue Samples for Imaging Mass Spectrometry

    Science.gov (United States)

    Mounfield, William P.; Garrett, Timothy J.

    2012-03-01

    Uniform matrix deposition on tissue samples for matrix-assisted laser desorption/ionization (MALDI) is key for reproducible analyte ion signals. Current methods often result in nonhomogenous matrix deposition, and take time and effort to produce acceptable ion signals. Here we describe a fully-automated method for matrix deposition using an enclosed spray chamber and spray nozzle for matrix solution delivery. A commercial air-atomizing spray nozzle was modified and combined with solenoid controlled valves and a Programmable Logic Controller (PLC) to control and deliver the matrix solution. A spray chamber was employed to contain the nozzle, sample, and atomized matrix solution stream, and to prevent any interference from outside conditions as well as allow complete control of the sample environment. A gravity cup was filled with MALDI matrix solutions, including DHB in chloroform/methanol (50:50) at concentrations up to 60 mg/mL. Various samples (including rat brain tissue sections) were prepared using two deposition methods (spray chamber, inkjet). A linear ion trap equipped with an intermediate-pressure MALDI source was used for analyses. Optical microscopic examination showed a uniform coating of matrix crystals across the sample. Overall, the mass spectral images gathered from tissues coated using the spray chamber system were of better quality and more reproducible than from tissue specimens prepared by the inkjet deposition method.

  15. Water movement through a shallow unsaturated zone in an inland arid region: Field drip irrigation experiment under matrix potential control

    Science.gov (United States)

    Zhou, T.; Han, D.; Song, X.

    2017-12-01

    It is vital to study soil water movement in unsaturated zone for evaluating and improving current irrigation mode for prevention and control of soil secondary salinization, especially in inland arid area, where is characterized by strong evaporation, poor drainage system and shallow water table depth. In this study, we investigated the applicability of drip irrigation under matrix potential control during cotton growth seasons in an inland arid region of northwest China. Combined physical observation with stable isotopes tracing method, we studied soil water flow system and recharge sources of shallow groundwater in heavy (Pilot 1) and light (Pilot 2) saline-alkali cotton fields. Evaporation depths (about 50-60 cm) are about the same for both pilots, but infiltration depths (about 60 cm for Pilot 1 and 150 cm for Pilot 2) are very different due to different soil texture, soil structure and soil salt content. Middle layer (about 100 cm thick) is a critical barrier for water exchange between surface and deep layer. Irrigation water is the major source (about 79.6% for Pilot 1 and 81.6% for Pilot 2), while evapotranspiration is the major sink (about 80.7% for Pilot 1 and 83.1% for Pilot 2) of unsaturated zone. The increase of soil water storage is not enough to make up the water shortage of middle layer and thus drip irrigation water doesn't recharge into groundwater for both pilots. Water table rise (about 60 cm for Pilot 1 and 50 cm for Pilot 2) could be caused by lateral groundwater flow instead of vertical infiltration. This irrigation mode could retard the water table rise in this region. However, improving horizontal drainage system may be indispensable for sustainable agriculture development. The study can provide important basis for soil secondary salinization prevention and agricultural water management in inland arid areas.

  16. A Current Control Approach for an Abnormal Grid Supplied Ultra Sparse Z-Source Matrix Converter with a Particle Swarm Optimization Proportional-Integral Induction Motor Drive Controller

    Directory of Open Access Journals (Sweden)

    Seyed Sina Sebtahmadi

    2016-11-01

    Full Text Available A rotational d-q current control scheme based on a Particle Swarm Optimization- Proportional-Integral (PSO-PI controller, is used to drive an induction motor (IM through an Ultra Sparse Z-source Matrix Converter (USZSMC. To minimize the overall size of the system, the lowest feasible values of Z-source elements are calculated by considering the both timing and aspects of the circuit. A meta-heuristic method is integrated to the control system in order to find optimal coefficient values in a single multimodal problem. Henceforth, the effect of all coefficients in minimizing the total harmonic distortion (THD and balancing the stator current are considered simultaneously. Through changing the reference point of magnitude or frequency, the modulation index can be automatically adjusted and respond to changes without heavy computational cost. The focus of this research is on a reliable and lightweight system with low computational resources. The proposed scheme is validated through both simulation and experimental results.

  17. Technological strategies to estimate and control diffusive passage times through the mucus barrier in mucosal drug delivery.

    Science.gov (United States)

    Newby, Jay M; Seim, Ian; Lysy, Martin; Ling, Yun; Huckaby, Justin; Lai, Samuel K; Forest, M Gregory

    2018-01-15

    In mucosal drug delivery, two design goals are desirable: 1) insure drug passage through the mucosal barrier to the epithelium prior to drug removal from the respective organ via mucus clearance; and 2) design carrier particles to achieve a prescribed arrival time and drug uptake schedule at the epithelium. Both goals are achievable if one can control "one-sided" diffusive passage times of drug carrier particles: from deposition at the mucus interface, through the mucosal barrier, to the epithelium. The passage time distribution must be, with high confidence, shorter than the timescales of mucus clearance to maximize drug uptake. For 100nm and smaller drug-loaded nanoparticulates, as well as pure drug powders or drug solutions, diffusion is normal (i.e., Brownian) and rapid, easily passing through the mucosal barrier prior to clearance. Major challenges in quantitative control over mucosal drug delivery lie with larger drug-loaded nanoparticulates that are comparable to or larger than the pores within the mucus gel network, for which diffusion is not simple Brownian motion and typically much less rapid; in these scenarios, a timescale competition ensues between particle passage through the mucus barrier and mucus clearance from the organ. In the lung, as a primary example, coordinated cilia and air drag continuously transport mucus toward the trachea, where mucus and trapped cargo are swallowed into the digestive tract. Mucus clearance times in lung airways range from minutes to hours or significantly longer depending on deposition in the upper, middle, lower airways and on lung health, giving a wide time window for drug-loaded particle design to achieve controlled delivery to the epithelium. We review the physical and chemical factors (of both particles and mucus) that dictate particle diffusion in mucus, and the technological strategies (theoretical and experimental) required to achieve the design goals. First we describe an idealized scenario - a homogeneous

  18. Biomaterials for Local, Controlled Drug Delivery to the Injured Spinal Cord

    Directory of Open Access Journals (Sweden)

    Alexis M. Ziemba

    2017-05-01

    Full Text Available Affecting approximately 17,000 new people each year, spinal cord injury (SCI is a devastating injury that leads to permanent paraplegia or tetraplegia. Current pharmacological approaches are limited in their ability to ameliorate this injury pathophysiology, as many are not delivered locally, for a sustained duration, or at the correct injury time point. With this review, we aim to communicate the importance of combinatorial biomaterial and pharmacological approaches that target certain aspects of the dynamically changing pathophysiology of SCI. After reviewing the pathophysiology timeline, we present experimental biomaterial approaches to provide local sustained doses of drug. In this review, we present studies using a variety of biomaterials, including hydrogels, particles, and fibers/conduits for drug delivery. Subsequently, we discuss how each may be manipulated to optimize drug release during a specific time frame following SCI. Developing polymer biomaterials that can effectively release drug to target specific aspects of SCI pathophysiology will result in more efficacious approaches leading to better regeneration and recovery following SCI.

  19. Magnetic nanoparticles for a new drug delivery system to control quercetin releasing for cancer chemotherapy

    International Nuclear Information System (INIS)

    Barreto, A. C. H.; Santiago, V. R.; Mazzetto, S. E.; Denardin, J. C.; Lavín, R.; Mele, Giuseppe; Ribeiro, M. E. N. P.; Vieira, Icaro G. P.; Gonçalves, Tamara; Ricardo, N. M. P. S.

    2011-01-01

    Quercetin belongs to the chemical class of flavonoids and can be found in many common foods, such as apples, nuts, berries, etc. It has been demonstrated that quercetin has a wide array of biological effects that are considered beneficial to health treatment, mainly as anticancer. However, therapeutic applications of quercetin have been restricted to oral administration due to its sparing solubility in water and instability in physiological medium. A drug delivery methodology was proposed in this work to study a new quercetin release system in the form of magnetite–quercetin–copolymer (MQC). These materials were characterized through XRD, TEM, IR, and Thermal analysis. In addition, the magnetization curves and quercetin releasing experiments were performed. It was observed a nanoparticle average diameter of 11.5 and 32.5 nm at Fe 3 O 4 and MQC, respectively. The presence of magnetic nanoparticles in this system offers the promise of targeting specific organs within the body. These results indicate the great potential for future applications of the MQC to be used as a new quercetin release system.

  20. In Vitro and In Vivo Evaluation of Niosomal Formulation for Controlled Delivery of Clarithromycin

    Directory of Open Access Journals (Sweden)

    Gyati Shilakari Asthana

    2016-01-01

    Full Text Available The present study was focused on formulating and evaluating clarithromycin (CLR containing niosomal formulation for in vitro and in vivo pharmacokinetic behavior. Niosomal formulations (empty and drug loaded were prepared by using different ratio of surfactant (various Span grades 20, 40, 60, and 80 and cholesterol by thin film hydration method and were evaluated for in vitro characteristics, stability studies, and in vivo study. Dicetyl phosphate (DCP was added to the niosomal formulation. Various pharmacokinetic parameters were determined from plasma of male SD rats. Span 60 containing niosomal formulation NC2 (cholesterol to surfactant ratio 1 : 1 displayed highest entrapment efficiency with desired particle size of 4.67 μm. TEM analyses showed that niosomal formulation was spherical in shape. Niosomes containing Span 60 displayed higher percentage of drug release after 24 h as compared to other formulations. NC2 formulation was found to be stable at the end of the study on storage condition. Various pharmacokinetic parameters, namely, AUC, AUMC, and MRT of niosomal formulation, were found to be 1.5-fold, 4-fold, and 3-fold plain drug, respectively. The present study suggested that niosomal formulations provide sustained and prolonged delivery of drug with enhance bioavailability.

  1. Hydrazone-Containing Triblock Copolymeric Micelles for pH-Controlled Drug Delivery

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    Peilan Qi

    2018-01-01

    Full Text Available In this study, the structure–activity relationship of amphiphilic block copolymer micelles as nanosized drug delivery system was revealed. Firstly, a biodegradable triblock polymers PEG-DiHyd-PLA containing hydrazone bond was synthesized through the ring-opening polymerization. In this method, PEG-DiHyd-Phenol was used as the initiator and L-lactide as the monomer. Then, the polymeric micelles were formed and used as nano-drug carriers with pH sensitivity. The structure and composition of the polymer were characterized by infrared (IR, nuclear magnetic resonance (1H-NMR, and gel permeation chromatography (GPC, we characterized the self-assembling process of the triblock polymers and the pH sensitivity of the micelles by the means of transmission electron microscopy (TEM, dynamic light scattering method (DLS. Doxorubicin (DOX acts as the model drug, and we researched the capacities of drug loading and release in vitro of the micelles. MTT experiments showed that the blank micelles of PEG-DiHyd-PLA were not cytotoxic to tumor cells (HepG-2, MCF-7 and normal cell (L-02 cells, but the DOX loaded ones displayed more toxicity than the ones without hydrazone, which was consistent to the further confocal laser scanning microscopy and flow cytometry study.

  2. Controlled adsorption and release onto calcium phosphates materials and drug delivery applications

    Directory of Open Access Journals (Sweden)

    Barroug A.

    2013-11-01

    Full Text Available The adsorptive properties of synthetic calcium phosphates analogous to bone mineral were examined with respect to cisplatin and risedronate, two biological active drugs; the uptake and release experiments were carried out under various conditions in order to understand the basic mechanism of interaction. The effect of temperature and solution composition were highlighted and discussed. The adsorption results obtained for the therapeutic agents demonstrated that, depending on the conditions investigated (nature of the sorbent, concentration range, ionic composition, temperature…, the shape of the isotherms is of Freundlich or Langmuir type. The adsorption is described as an ion-exchange process in dilute solutions, while the interaction appears to be reactive for concentrated solutions (dissolution of mineral ions from the apatite substrate and formation of soluble calcium complex and/or precipitation of calcium salts involving sorbate molecules. The information gained on the surface reactivity of calcium phosphate were exploited to associate an antibiotic to calcium phosphate cements for drug delivery applications. The specimens were obtained by combination of calcium phosphate and calcium carbonate powders upon mixing with water. The physicochemical properties of the paste were altered by the drug loading method (in the liquid or solid phase. Thus, a dose-dependent effect was noticed for the paste setting time, hardening and the release process.

  3. Influence of particle size of nano zinc oxide on the controlled delivery of Amoxicillin

    Science.gov (United States)

    Palanikumar, L.; Ramasamy, S.; Hariharan, G.; Balachandran, C.

    2013-10-01

    A great effort has been exerted to develop drug carriers aiming at satisfying the requirements, such as safety, greater efficiency, predictable therapeutic response, and prolonged release period. The present study aims at developing the use of zinc oxide nanoparticles as a carrier as a function of particle size for amoxicillin drug delivery system. The amoxicillin-loaded zinc oxide nanoparticles have a good antibacterial activity against infectious Gram-positive and Gram-negative bacteria. Zinc oxide nanoparticles have been prepared by wet chemical precipitation method varying the pH values. Particle size and morphology of the as-prepared ZnO powders are characterized by X-ray diffraction, Fourier transform infrared spectroscopy and transmission electron microscope. Drug loading, in vitro drug release and antibacterial activity have been analyzed. Maximum zone of inhibition is observed for Staphylococcus epidermis. The results show that inhibitory efficacy of drug-loaded ZnO nanoparticles is very much dependent on its chosen concentration, drug loading, and size.

  4. Intramuscular versus intravenous prophylactic oxytocin for postpartum hemorrhage after vaginal delivery: a randomized controlled study.

    Science.gov (United States)

    Dagdeviren, Hediye; Cengiz, Huseyin; Heydarova, Ulkar; Caypinar, Sema Suzen; Kanawati, Ammar; Guven, Ender; Ekin, Murat

    2016-11-01

    Prevention of postpartum haemorrhage (PPH) is essential in the pursuit of improved health care for women. Oxytocin, the most commonly used uterotonic agent to prevent PPH, has no established the route of administration. In this study we aimed to compare whether the mode of oxytocin administration, i.e., intravenous and intramuscular administration, has an effect on the potential benefits and side effects. A total of 256 women were randomised into two groups: intramuscular group (128) or intravenous group (128). Estimated blood loss during the third stage of labour was similar between the two groups (p = 0.572). Further there were no statistically significant difference was noted between the two groups in terms of the mean duration of labor, duration of the third stage of labor, manual removal of the placenta, need for instrumental delivery, need for blood transfusion, PPH ≥500 mL, PPH ≥1000 mL, or length of hospital stay. Using oxytocin by intravenous and intramuscular route has a similar efficacy and adverse effects.

  5. Formulation and evaluation of gastroretentive microballoons containing baclofen for a floating oral controlled drug delivery system.

    Science.gov (United States)

    Dube, T S; Ranpise, N S; Ranade, A N

    2014-01-01

    The objective of the present study was to fabricate and evaluate a multiparticulate oral gastroretentive dosage form of baclofen characterized by a central large cavity (hollow core) promoting unmitigated floatation with practical applications to alleviate the signs and symptoms of spasticity and muscular rigidity. Solvent diffusion and evaporation procedure were applied to prepare floating microspheres with a central large cavity using various combinations of ethylcellulose (release retardant) and HPMC K4M (release modifier) dissolved in a mixture of dichloromethane and methanol (2:1). The obtained microspheres (700-1000 µm) exhibit excellent floating ability (86 ± 2.00%) and release characteristics with entrapment efficiency of 95.2 ± 0.32%. Microspheres fabricated with ethylcellulose to HPMC K4M in the ratio 8.5:1.5 released 98.67% of the entrapped drug in 12 h. Muscle relaxation caused by baclofen microspheres impairs the rotarod performance for more than 12 h. Abdominal X-ray images showed that the gastroretention period of the floating barium sulfate- labeled microspheres was no less than 10 h. The buoyant baclofen microspheres provide a promising gastroretentive drug delivery system to deliver baclofen in spastic patients with a sustained release rate.

  6. Controlled Antibiotic Delivery by Gelatin Nanospheres: Optimization, Characterization and Antibacterial Evaluation

    Directory of Open Access Journals (Sweden)

    Shahrzad Fathollahipour

    2016-10-01

    Full Text Available The present work focuses on preparation and characterization of erythromycin loaded gelatin nanoparticles through nanoprecipitation method. The procedure consists of the addition of the aqueous gelatin solution to the non-solvent phase containing Lutherol F127. Three different measures of cross-linker and polymer concentration were also examined, and the optimum concentration was found. The morphology of gelatin nanoparticles was characterized by field emission scanning electron microscope. It was shown that the optimal morphology can be achieved at the concentration of 1.25 wt % of gelatin in aqueous phase by addition of 20 mL of glutaraldehyde 5%, as the crosslinking agent. Nanoparticle wet size determination was carried out using a dynamic light scattering system and found to be approximately 100 nm. Furthermore, Erythromycin release studies proved the suitability of these particles as a drug delivery system, at least in the studied 72 hours interval. As suggested by related measurements, these nanoparticles are good candidates for antibacterial agent release in any possible related application.

  7. Controlled delivery of the anti-VEGF aptamer EYE001 with poly(lactic-co-glycolic)acid microspheres.

    Science.gov (United States)

    Carrasquillo, Karen G; Ricker, Joseph A; Rigas, Ioannis K; Miller, Joan W; Gragoudas, Evangelos S; Adamis, Anthony P

    2003-01-01

    To develop a controlled-drug delivery system for the long-term inhibition of vascular endothelial growth factor (VEGF) and its mediated responses. Poly(lactic-co-glycolic)acid (PLGA) microspheres containing anti-VEGF RNA aptamer (EYE001) formulations in the solid-state were developed by an oil-in-oil solvent evaporation process. In vitro experiments were performed to characterize the release profiles. Stability and bioactivity of the released drug were assayed by monitoring the RNA aptamer's ability to inhibit VEGF-induced cell proliferation in human umbilical vein endothelial cells (HUVECs). Cell proliferation experiments were conducted with aptamer aliquots collected after short-, mid-, and long-term release time points. To investigate the feasibility of this polymer device as a potential transscleral delivery device, an in vitro apparatus was developed to assess polymer hydration and degradation through rabbit sclera and subsequent delivery through it. PLGA microspheres were able to deliver EYE001 in a sustained manner, with an average rate of 2 micro g/d over a period of 20 days. Solid-state stabilization of the aptamer with disaccharide trehalose before lyophilization and encapsulation in PLGA rendered the drug more stable after release. Cell proliferation experiments demonstrated that the bioactivity of the aptamer was preserved after release, as indicated by inhibition of endothelial cell proliferation after incubation with VEGF. Microspheres packed into a sealed chamber and placed onto the "orbital" part of a rabbit sclera for a period of 6 days became hydrated and started to degrade, as shown by scanning electron microscopy (SEM). As a result, the aptamer was delivered from the microspheres through the sclera, as determined spectrophotometrically. The loading of aptamer-containing microspheres into a device and placing it on the orbital surface of the sclera was assessed and shown to be feasible. RNA aptamer EYE001 encapsulated in PLGA was delivered over a

  8. A randomized controlled trial of uterine exteriorization versus in situ repair of the uterine incision during cesarean delivery.

    Science.gov (United States)

    El-Khayat, Waleed; Elsharkawi, Mohamed; Hassan, Amr

    2014-11-01

    To compare extra-abdominal repair of the uterine incision at cesarean delivery with in situ repair. The present study was a double-blind randomized controlled trial conducted at a university hospital in Egypt during 2012-2013, and included women with an indication for cesarean delivery. Extra-abdominal repair was used in group 1 (n=500) and in situ repair in group 2 (n=500). The primary outcome measure was the surgery duration. Surgery duration was significantly longer in group 1 than group 2 (49.9±2.3 minutes vs 39.9±1.8 minutes; P<0.001). More patients in group 1 than in group 2 had postoperative moderate-to-severe pain (165 [33.0%] vs 115 [23.0%]; P=0.001) and needed additional postoperative analgesia (100 [20.0%] vs 50 [10.0%]; P<0.001). Moreover, mean time to bowel movement was longer in group 1 than in group 2 (17.0±2.7 hours vs 14.0±1.9 hours; P<0.001). In situ uterine closure is more advantageous than extra-abdominal repair in terms of surgery duration, postoperative pain and need for additional analgesia, and return of bowel movement. ClinicalTrials.gov:NCT01723605. Copyright © 2014 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  9. Randomised controlled single-blind study of conventional versus depot mydriatic drug delivery prior to cataract surgery

    Directory of Open Access Journals (Sweden)

    Madge Simon

    2006-11-01

    Full Text Available Abstract Background A prerequisite for safe cataract surgery is an adequately dilated pupil. The authors conducted a trial to assess the efficacy (in terms of pupil diameter of a depot method of pre-operative pupil dilatation, as compared with repeated instillations of drops (which is time-consuming for the nursing staff and uncomfortable for the patient. Methods A prospective randomised masked trial was conducted comprising 130 patients with no significant ocular history undergoing elective clear corneal phacoemulsification. 65 patients had mydriatic drops (Tropicamide 1%, Phenylephrine 2.5%, Diclofenac sodium 0.1% instilled prior to surgery, 65 had a wick soaked in the same drop mixture placed in the inferior fornix. Horizontal pupil diameters were recorded on a millimetre scale immediately prior to surgery. Results There was no significant difference in pupil size between the two groups (p = 0.255, Student's t-test. Conclusion There was no significant difference between the mydriasis obtained with the depot system compared with conventional drop application. Use of a depot mydriatic delivery system appears to be a safe and efficient method of drug delivery. Trial Registration International Standard Randomised Controlled Trial Number Register ISRCTN78047760

  10. Effects of zinc supplementation during pregnancy on pregnancy outcome in women with history of preterm delivery: a double-blind randomized, placebo-controlled trial.

    Science.gov (United States)

    Danesh, Azar; Janghorbani, Mohsen; Mohammadi, Belghis

    2010-05-01

    The aim of this study was to assess the effect of high dose zinc (Zn) supplement during pregnancy in pregnancy outcome in healthy pregnant women with a previous preterm delivery in Isfahan, Iran. A double-blind placebo-controlled randomized clinical trial was conducted between January 2007 and June 2008. Eighty-four pregnant women with a previous preterm delivery age 19 to 35 years were randomly allocated to receive either 50 mg/day Zn as Zn sulfate or placebo from 12 to 16 weeks of gestation till delivery. Pregnancy outcome was assessed in term of incidence of intrauterine growth retardation (IUGR), birth weight, crown-heel length, head circumference, Apgar score, and gestational age at delivery. The mean birth head circumference was higher in Zn supplemented group than in the placebo group (35.0 cm vs. 33.7 cm, P delivery (37.1 week vs. 36.7 week) and birth weight (2960.6 g vs. 2819.0 g) of babies born in Zn supplemented group was slightly higher than placebo group, it was not statistically significant. No significant differences were seen for infant length, Apgar score, and IUGR. Adding Zn supplementation during pregnancy to routine care of women with a previous preterm delivery had no significant effect on the gestational age at delivery and birth weight but increased the birth head circumference.

  11. Parallel Programming Application to Matrix Algebra in the Spectral Method for Control Systems Analysis, Synthesis and Identification

    Directory of Open Access Journals (Sweden)

    V. Yu. Kleshnin

    2016-01-01

    Full Text Available The article describes the matrix algebra libraries based on the modern technologies of parallel programming for the Spectrum software, which can use a spectral method (in the spectral form of mathematical description to analyse, synthesise and identify deterministic and stochastic dynamical systems. The developed matrix algebra libraries use the following technologies for the GPUs: OmniThreadLibrary, OpenMP, Intel Threading Building Blocks, Intel Cilk Plus for CPUs nVidia CUDA, OpenCL, and Microsoft Accelerated Massive Parallelism.The developed libraries support matrices with real elements (single and double precision. The matrix dimensions are limited by 32-bit or 64-bit memory model and computer configuration. These libraries are general-purpose and can be used not only for the Spectrum software. They can also find application in the other projects where there is a need to perform operations with large matrices.The article provides a comparative analysis of the libraries developed for various matrix operations (addition, subtraction, scalar multiplication, multiplication, powers of matrices, tensor multiplication, transpose, inverse matrix, finding a solution of the system of linear equations through the numerical experiments using different CPU and GPU. The article contains sample programs and performance test results for matrix multiplication, which requires most of all computational resources in regard to the other operations.

  12. A control volume scheme for three-dimensional transport: buffer and matrix effect on a decay chain transport in the repository

    International Nuclear Information System (INIS)

    Lee, Y. M.; Hwang, Y. S.; Kim, S. G.; Kang, C. H.

    2002-01-01

    Using a three-dimensional numerical code, B3R developed for nuclide transport of an arbitrary length of decay chain in the buffer between the canister and adjacent rock in a high-level radioactive waste repository by adopting a finite difference method utilizing the control-volume scheme, some illustrative calculations have been done. A linear sorption isotherm, nuclide transport due to diffusion in the buffer and the rock matrix, and advection and dispersion along thin rigid parallel fractures existing in a saturated porous rock matrix as well as diffusion through the fracture wall into the matrix is assumed. In such kind of repository, buffer and rock matrix are known to be important physico-chemical barriers in nuclide retardation. To show effects of buffer and rock matrix on nuclide transport in HLW repository and also to demonstrate usefulness of B3R, several cases of breakthrough curves as well as three-dimensional plots of concentration isopleths associated with these two barriers are introduced for a typical case of decay chain of 234 U→ 230 Th→ 226 Ra, which is the most important chain as far as the human environment is concerned

  13. Fabrication of doxorubicin nanoparticles by controlled antisolvent precipitation for enhanced intracellular delivery.

    Science.gov (United States)

    Tam, Yu Tong; To, Kenneth Kin Wah; Chow, Albert Hee Lum

    2016-03-01

    Over-expression of ATP-binding cassette transporters is one of the most important mechanisms responsible for multidrug resistance. Here, we aimed to develop a stable polymeric nanoparticle system by flash nanoprecipitation (FNP) for enhanced anticancer drug delivery into drug resistant cancer cells. As an antisolvent precipitation process, FNP works best for highly lipophilic solutes (logP>6). Thus we also aimed to evaluate the applicability of FNP to drugs with relatively low lipophilicity (logP=1-2). To this end, doxorubicin (DOX), an anthracycline anticancer agent and a P-gp substrate with a logP of 1.3, was selected as a model drug for the assessment. DOX was successfully incorporated into the amphiphilic diblock copolymer, polyethylene glycol-b-polylactic acid (PEG-b-PLA), by FNP using a four-stream multi-inlet vortex mixer. Optimization of key processing parameters and co-formulation with the co-stabilizer, polyvinylpyrrolidone, yielded highly stable, roughly spherical DOX-loaded PEG-b-PLA nanoparticles (DOX.NP) with mean particle size below 100nm, drug loading up to 14%, and drug encapsulation efficiency up to 49%. DOX.NP exhibited a pH-dependent drug release profile with higher cumulative release rate at acidic pHs. Surface analysis of DOX.NP by XPS revealed an absence of DOX on the particle surface, indicative of complete drug encapsulation. While there were no significant differences in cytotoxic effect on P-gp over-expressing LCC6/MDR cell line between DOX.NP and free DOX in buffered aqueous media, DOX.NP exhibited a considerably higher cellular uptake and intracellular retention after efflux. The apparent lack of cytotoxicity enhancement with DOX.NP may be attributable to its slow DOX release inside the cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Fibrin nanoconstructs: a novel processing method and their use as controlled delivery agents

    International Nuclear Information System (INIS)

    Praveen, G; Sreerekha, P R; Menon, Deepthy; Nair, Shantikumar V; Chennazhi, Krishna Prasad

    2012-01-01

    Fibrin nanoconstructs (FNCs) were prepared through a modified water-in-oil emulsification–diffusion route without the use of any surfactants, resulting in a high yield synthesis of fibrin nanotubes (FNTs) and fibrin nanoparticles (FNPs). The fibrin nanoconstructs formed an aligned structure with self-assembled nanotubes with closed heads that eventually formed spherical nanoparticles of size ∼250 nm. The nanotubes were typically ∼700 nm long and 150–300 nm in diameter, with a wall thickness of ∼50 nm and pore diameter of about 150–250 nm. These constructs showed high stability against aggregation indicated by a zeta potential of −44 mV and an excellent temperature stability upto 200 °C. Furthermore, they were found to be enzymatically degradable, thereby precluding any long term toxicity effects. These unique fibrin nanostructures were analyzed for their ability to deliver tacrolimus, an immunosuppressive drug that is used widely to prevent the initial phase of tissue rejection during allogenic transplantation surgeries. Upon conjugation with tacrolimus, a drug encapsulation efficiency of 66% was achieved, with the in vitro release studies in PBS depicting a sustained and complete drug release over a period of one week at the physiological pH of 7.4. At a more acidic pH, the drug release was very slow, suggesting their potential for oral–intestinal drug administration as well. The in vivo drug absorption rates analyzed in Sprague Dawley rats further confirmed the sustained release pattern of tacrolimus for both oral and parenteral delivery routes. The novel fibrin nanoconstructs developed using a green chemistry approach thus proved to be excellent biodegradable nanocarriers for oral as well as parenteral administrations, with remarkable potential also for delivering specific growth factors in tissue engineering scaffolds. (paper)

  15. The impact of price and tobacco control policies on the demand for electronic nicotine delivery systems.

    Science.gov (United States)

    Huang, Jidong; Tauras, John; Chaloupka, Frank J

    2014-07-01

    While much is known about the demand for conventional cigarettes, little is known about the determinants of demand for electronic nicotine delivery systems (ENDS or e-cigarettes). The goal of this study is to estimate the own and cross-price elasticity of demand for e-cigarettes and to examine the impact of cigarette prices and smoke-free policies on e-cigarette sales. Quarterly e-cigarette prices and sales and conventional cigarette prices from 2009 to 2012 were constructed from commercial retail store scanner data from 52 U.S. markets, for food, drug and mass stores, and from 25 markets, for convenience stores. Fixed-effects models were used to estimate the own and cross-price elasticity of demand for e-cigarettes and associations between e-cigarette sales and cigarette prices and smoke-free policies. Estimated own price elasticities for disposable e-cigarettes centred around -1.2, while those for reusable e-cigarettes were approximately -1.9. Disposable e-cigarette sales were higher in markets where reusable e-cigarette prices were higher and where less of the population was covered by a comprehensive smoke-free policy. There were no consistent and statistically significant relationships between cigarette prices and e-cigarette sales. E-cigarette sales are very responsive to own price changes. Disposable e-cigarettes appear to be substitutes for reusable e-cigarettes. Policies increasing e-cigarette retail prices, such as limiting rebates, discounts and coupons and imposing a tax on e-cigarettes, could potentially lead to significant reductions in e-cigarette sales. Differential tax policies based on product type could lead to substitution between different types of e-cigarettes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  16. UAV Delivery Monitoring System

    Directory of Open Access Journals (Sweden)

    San Khin Thida

    2018-01-01

    Full Text Available UAV-based delivery systems are increasingly being used in the logistics field, particularly to achieve faster last-mile delivery. This study develops a UAV delivery system that manages delivery order assignments, autonomous flight operation, real time control for UAV flights, and delivery status tracking. To manage the delivery item assignments, we apply the concurrent scheduler approach with a genetic algorithm. The present paper describes real time flight data based on a micro air vehicle communication protocol (MAVLink. It also presents the detailed hardware components used for the field tests. Finally, we provide UAV component analysis to choose the suitable components for delivery in terms of battery capacity, flight time, payload weight and motor thrust ratio.

  17. Fractones: extracellular matrix niche controlling stem cell fate and growth factor activity in the brain in health and disease.

    Science.gov (United States)

    Mercier, Frederic

    2016-12-01

    The stem cell niche refers to a specific microenvironment where stem cells proliferate and differentiate to produce new specialized cells throughout an organism's adulthood. Growth factors are crucial signaling molecules that diffuse through the extracellular space, reach the stem cell niche, and ultimately promote stem cell proliferation and differentiation. However, it is not well known how multiple growth factors, often with antagonistic activities, work together in the stem cell niche to select target stem cell populations and determine stem cell fate. There is accumulating evidence suggesting that extracellular matrix (ECM) molecules play an important role in promoting growth factor access and activity in the stem cell niche. In the adult brain neurogenic zone, where neural stem cells (NSCs) reside, there exist specialized ECM structures, which we have named fractones. The processes of NSC allow them to come into contact with fractones and interact with its individual components, which include heparan sulfate proteoglycans (HSPGs) and laminins. We have demonstrated that fractone-associated HSPGs bind growth factors and regulate NSC proliferation in the neurogenic zone. Moreover, emerging results show that fractones are structurally altered in animal models with autism and adult hydrocephalus, as demonstrated by changes in fractone size, quantity, or HSPG content. Interestingly, ECM structures similar to fractones have been found throughout β-amyloid plaques in the brain of patients with Alzheimer's disease. Pathological fractones may cause imbalances in growth factor activity and impair neurogenesis, leading to inflammation and disorder. Generally speaking, these stem cell niche structures play a potentially vital role in controlling growth factor activity during both health and disease.

  18. Emulsion-based encapsulation and delivery of nanoparticles for the controlled release of alkalinity within the subsurface environment

    Science.gov (United States)

    Ramsburg, C. A.; Muller, K.; Gill, J.

    2012-12-01

    Many current approaches to managing groundwater contamination rely on further advances in amendment delivery in order to initiate and sustain contaminant degradation or immobilization. In fact, limited or ineffective delivery is often cited when treatment objectives are not attained. Emulsions, specifically oil-in-water emulsions, have demonstrated potential to aid delivery of remediation amendments. Emulsions also afford opportunities to control the release of active ingredients encapsulated within the droplets. Our research is currently focused on the controlled release of nanoparticle-based buffering agents using oil-in-water emulsions. This interest is motivated by the fact that chemical and biological processes employed for the remediation and stewardship of contaminated sites often necessitate control of pH during treatment and, in some cases, long thereafter. Alkalinity-release nanoparticles (e.g., CaCO3, MgO) were suspended within soybean oil and subsequently encapsulated by through the creation of oil-in-water emulsions. These oil-in-water emulsions are designed to have physical properties which are favorable for subsurface delivery (nominal properties: 1 g/mL density; 10 cP viscosity; and 1.5 μm droplet diameter). Buffer capacity titrations suggest that MgO particles are moderately more accessible within the oil phase and nearly twice as effective (on a per mass basis) at releasing alkalinity (as compared to the CaCO3 particles). Results from experiments designed to assess the release kinetics suggest that a linear driving force model is capable of describing the release process and mass transfer coefficients are constant through the reactive life of the emulsion. The release kinetics in emulsions containing MgO particles were found to be three orders of magnitude faster than those quantified for emulsions containing CaCO3. The slower release kinetics of the emulsions containing CaCO3 particles may prove beneficial when considering pH control at sites

  19. Matrix calculus

    CERN Document Server

    Bodewig, E

    1959-01-01

    Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well

  20. Controlled delivery of tauroursodeoxycholic acid from biodegradable microspheres slows retinal degeneration and vision loss in P23H rats.

    Directory of Open Access Journals (Sweden)

    Laura Fernández-Sánchez

    Full Text Available Successful drug therapies for treating ocular diseases require effective concentrations of neuroprotective compounds maintained over time at the site of action. The purpose of this work was to assess the efficacy of intravitreal controlled delivery of tauroursodeoxycholic acid (TUDCA encapsulated in poly(D,L-lactic-co-glycolic acid (PLGA microspheres for the treatment of the retina in a rat model of retinitis pigmentosa. PLGA microspheres (MSs containing TUDCA were produced by the O/W emulsion-solvent evaporation technique. Particle size and morphology were assessed by light scattering and scanning electronic microscopy, respectively. Homozygous P23H line 3 rats received a treatment of intravitreal injections of TUDCA-PLGA MSs. Retinal function was assessed by electroretinography at P30, P60, P90 and P120. The density, structure and synaptic contacts of retinal neurons were analyzed using immunofluorescence and confocal microscopy at P90 and P120. TUDCA-loaded PLGA MSs were spherical, with a smooth surface. The production yield was 78%, the MSs mean particle size was 23 μm and the drug loading resulted 12.5 ± 0.8 μg TUDCA/mg MSs. MSs were able to deliver the loaded active compound in a gradual and progressive manner over the 28-day in vitro release study. Scotopic electroretinografic responses showed increased ERG a- and b-wave amplitudes in TUDCA-PLGA-MSs-treated eyes as compared to those injected with unloaded PLGA particles. TUDCA-PLGA-MSs-treated eyes showed more photoreceptor rows than controls. The synaptic contacts of photoreceptors with bipolar and horizontal cells were also preserved in P23H rats treated with TUDCA-PLGA MSs. This work indicates that the slow and continuous delivery of TUDCA from PLGA-MSs has potential neuroprotective effects that could constitute a suitable therapy to prevent neurodegeneration and visual loss in retinitis pigmentosa.

  1. Development of a dose-controlled multiculture cell exposure chamber for efficient delivery of airborne and engineered nanoparticles

    International Nuclear Information System (INIS)

    Asimakopoulou, Akrivi; Daskalos, Emmanouil; Papaioannou, Eleni; Konstandopoulos, Athanasios G; Lewinski, Nastassja; Riediker, Michael

    2013-01-01

    In order to study the various health influencing parameters related to engineered nanoparticles as well as to soot emitted by Diesel engines, there is an urgent need for appropriate sampling devices and methods for cell exposure studies that simulate the respiratory system and facilitate associated biological and toxicological tests. The objective of the present work was the further advancement of a Multiculture Exposure Chamber (MEC) into a dose-controlled system for efficient delivery of nanoparticles to cells. It was validated with various types of nanoparticles (Diesel engine soot aggregates, engineered nanoparticles for various applications) and with state-of-the-art nanoparticle measurement instrumentation to assess the local deposition of nanoparticles on the cell cultures. The dose of nanoparticles to which cell cultures are being exposed was evaluated in the normal operation of the in vitro cell culture exposure chamber based on measurements of the size specific nanoparticle collection efficiency of a cell free device. The average efficiency in delivering nanoparticles in the MEC was approximately 82%. The nanoparticle deposition was demonstrated by Transmission Electron Microscopy (TEM). Analysis and design of the MEC employs Computational Fluid Dynamics (CFD) and true to geometry representations of nanoparticles with the aim to assess the uniformity of nanoparticle deposition among the culture wells. Final testing of the dose-controlled cell exposure system was performed by exposing A549 lung cell cultures to fluorescently labeled nanoparticles. Delivery of aerosolized nanoparticles was demonstrated by visualization of the nanoparticle fluorescence in the cell cultures following exposure. Also monitored was the potential of the aerosolized nanoparticles to generate reactive oxygen species (ROS) (e.g. free radicals and peroxides generation), thus expressing the oxidative stress of the cells which can cause extensive cellular damage or damage on DNA.

  2. Low-dose SoluMatrix diclofenac in patients with osteoarthritis pain: impact on quality of life in a controlled trial.

    Science.gov (United States)

    Strand, Vibeke; Bergman, Martin; Singh, Jasvinder A; Gibofsky, Allan; Kivitz, Alan; Young, Clarence

    2017-06-01

    Low-dose SoluMatrix diclofenac was developed to provide effective pain relief for osteoarthritis pain. We evaluated the effects of SoluMatrix diclofenac on health-related quality of life (HRQoL) measures in patients with osteoarthritis, hypothesizing that SoluMatrix-treated patients would experience significant improvement compared with placebo. In this 12-week, phase 3 randomized controlled trial, 305 patients with osteoarthritis of the hip or knee received SoluMatrix diclofenac 35 mg three times (TID) or twice (BID) daily or placebo. Measures included HRQoL, assessed by Short Form 36 (SF-36, version 2), and pain, stiffness, and physical function, assessed by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at baseline and at week 12. Descriptive statistics were calculated for mean changes from baseline; inferential statistics compared treatment groups with placebo. SoluMatrix diclofenac 35 mg BID (6.2 [0.75]; P = 0.0048) or TID (6.6 [0.80]; P = 0.0014) produced large improvements in the SF-36 physical component summary (PCS) scores at week 12 (least squares mean change from baseline [SE]) compared with placebo (3.5 [0.78]). Minimum clinically important differences were observed in six out of eight SF-36 domains among patients in SoluMatrix diclofenac groups and five out of eight domains in the placebo group; treatment with SoluMatrix diclofenac 35 mg TID produced significant improvements (P ≤ 0.03) in five out of eight domains versus placebo. SoluMatrix diclofenac 35 mg TID significantly improved responses to 23 out of 24 questions in the WOMAC versus placebo (P ≤ 0.0334). Low-dose SoluMatrix diclofenac 35 mg TID and BID significantly improved HRQoL, pain, stiffness, and physical function in patients with osteoarthritis of the hip or knee.

  3. Matrix superpotentials

    Science.gov (United States)

    Nikitin, Anatoly G.; Karadzhov, Yuri

    2011-07-01

    We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.

  4. An Instructional Delivery System for Manpower Management: A Report for Water Pollution Control Agencies. Second Edition.

    Science.gov (United States)

    New York State Dept. of Environmental Conservation, Albany.

    This report contains information to assist organizations and personnel responsible for the quality and quantity of operators available for water quality control efforts. The text discusses in detail the current developments in operator instructional programs. Each of the seven sections of this report deals with a specific aspect of manpower…

  5. Facile synthesis of biphasic calcium phosphate microspheres with engineered surface topography for controlled delivery of drugs and proteins.

    Science.gov (United States)

    Zarkesh, Ibrahim; Ghanian, Mohammad Hossein; Azami, Mahmoud; Bagheri, Fatemeh; Baharvand, Hossein; Mohammadi, Javad; Eslaminejad, Mohamadreza Baghaban

    2017-09-01

    Biphasic calcium phosphate (BCP) microspheres are of great interest due to their high stability and osteoinductive properties at specific compositions. However, the need for optimal performance at a unique composition limits their flexibility for tuning drug release by modulation of bulk properties and presents the question of engineering surface topography as an alternative. It is necessary to have a facile method to control surface topography at a defined bulk composition. Here, we have produced BCP microspheres with different surface topographies that have the capability to be used as tunable drug release systems. We synthesized calcium deficient hydroxyapatite (CDHA) microparticles by precipitating calcium and phosphate ions onto ethylenediaminetetraacetic acid (EDTA) templates. The morphology and surface topography of CDHA microparticles were controlled using process parameters, which governed nucleation and growth. These parameters included template concentration, heat rate, and stirring speed. Under low heat rate and static conditions, we could obtain spherical microparticles with long and short nanosheets on their surfaces at low and high EDTA concentrations, respectively. These nanostructured microspheres were subsequently crystallized by thermal treatment to produce EDTA-free BCP microspheres with intact morphology. These biocompatible BCP microspheres were highly effective in loading and prolonged release of both small molecule [dexamethasone (Dex)] and protein [bovine serum albumin (BSA)] models. This strategy has enabled us to control the surface topography of BCP microspheres at defined compositions and holds tremendous promise for drug delivery and tissue engineering applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Luteinizing hormone-releasing hormone targeted superparamagnetic gold nanoshells for a combination therapy of hyperthermia and controlled drug delivery.

    Science.gov (United States)

    Mohammad, Faruq; Al-Lohedan, Hamad A

    2017-07-01

    In this, we developed superparamagnetic iron oxide nanoparticles (SPIONs) to be appropriate for the diagnosis and treatment of cancer cells by means of magnetic resonance imaging (MRI) and magnetically controlled hyperthermia/drug delivery (respectively). For the preparation of composite, we started with SPIONs, followed by its coating with gold to form SPIONs@Au, which further conjugated with luteinizing hormone-releasing hormone (LHRH) protein by making use of the cysteamine (Cyst) space linker and finally loaded with 5-Fluororacil (5-Fu) anticancer drug to form SPIONs@Au-Cyst-LHRH_5-Fu composite. Thus formed composite was thoroughly characterized by making use of the instrumental analysis such as HRTEM, EDAX, DLS, TGA, XPS, UV-vis, FTIR, HPLC and SQUID magnetics. We found from the analysis that the particles are spherical in shape, monodispersed with a size distribution of around 6.9nm in powdered dry form, while in solution phase it is 8.7nm. The UV-vis, FTIR, and HPLC studies confirmed for the loading of the 5-Fu drug onto the surface of SPIONs core and the maximum amount of drug that got adsorbed to be about 42%. The SQUID magnetic studies provided the information for the superparamagnetic behavior of the drug loaded SPIONs and the saturation magnetization (Ms) values observed to be about 11emu/g and the blocking temperature (T B ) of 348K. On testing the particles to see the effects of magnetic fluid hyperthermia (MFH) due to some changes in the solvent medium and oscillating frequency, the material seems to be highly active in aqueous medium and the activity gets increased with respect to the applied frequency of oscillation (430Hz>230Hz>44Hz). From the heat release studies, the calculated specific power loss (SPL) values for the SPIONs@Au-Cyst-LHRH_5-Fu composite are at the highest of 1068W/g in water (430Hz) vs the least of 68W/g in toluene (44Hz). Further, the drug release studies tested under the influence of magnetic field provided the information that

  7. Preparation of TPP-crosslinked chitosan microparticles by spray drying for the controlled delivery of progesterone intended for estrus synchronization in cattle.

    Science.gov (United States)

    Helbling, Ignacio M; Busatto, Carlos A; Fioramonti, Silvana A; Pesoa, Juan I; Santiago, Liliana; Estenoz, Diana A; Luna, Julio A

    2018-02-20

    Planned reproduction in cattle involves regulation of estrous cycle and the use of artificial insemination. Cycle control includes the administration of exogenous progesterone during 5-8 days in a controlled manner allowing females to synchronize their ovulation. Several progesterone delivery systems are commercially available but they have several drawbacks. The aim of the present contribution was to evaluate chitosan microparticles entrapping progesterone as an alternative system. Microparticles were prepared by spray drying. The effect of formulation parameters and experimental conditions on particle features and delivery was studied. A mathematical model to predict progesterone plasma concentration in animals was developed and validated with experimental data. Microparticle size was not affected by formulation parameters but sphericity enhances as Tween 80 content increases and it impairs as TPP content rises. Z potential decreases as phosphate content rises. Particles remain stable in acidic solution but the addition of surfactant is required to stabilize dispersions in neutral medium. Encapsulation efficiencies was 69-75%. In vitro delivery studies showed burst and diffusion-controlled phases, being progesterone released faster at low pH. In addition, delivery extend in cows was affected mainly by particle size and hormone initial content, while the amount injected altered plasma concentration. Theoretical predictions with excellent accuracy were obtained. The mathematical model developed can help to find proper particle features to reach specific delivery rates in the animals. This not only save time, money and effort but also minimized experimentation with animals which is desired from an ethical point of view.

  8. Hacking the Matrix.

    Science.gov (United States)

    Czerwinski, Michael; Spence, Jason R

    2017-01-05

    Recently in Nature, Gjorevski et al. (2016) describe a fully defined synthetic hydrogel that mimics the extracellular matrix to support in vitro growth of intestinal stem cells and organoids. The hydrogel allows exquisite control over the chemical and physical in vitro niche and enables identification of regulatory properties of the matrix. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. A passive apparatus for controlled-flux delivery of biocides: hydrogen peroxide as an example

    DEFF Research Database (Denmark)

    Olsen, Stefan Møller; Pedersen, L.T.; Dam-Johansen, Kim

    2010-01-01

    A new test method has been developed to estimate the required release rate of hydrogen peroxide (H2O2) to prevent marine biofouling. The technique exploits a well-defined concentration gradient of biocide across a cellulose acetate membrane. A controlled flux of H2O2, an environmentally friendly...... biocide, was obtained. Larvae of the barnacle, Balanus improvisus, were subjected to known release rates of H2O2 from a surface, under laboratory conditions. It was found that the distribution of settled larvae was not significantly different from the controls when H2O2 fluxes of 5-8 mu g cm(-2) day(-1......) were applied. However, release rates of 40 mu g cm(-2) day(-1) significantly displaced the distribution of settled larvae towards the area of the chamber farthest away from the membrane. Membrane tests in seawater (Jyllinge Harbour, Denmark) for over 16 weeks showed that release rates of H2O2...

  10. Nanoparticle-Laden Contact Lens for Controlled Ocular Delivery of Prednisolone: Formulation Optimization Using Statistical Experimental Design

    Directory of Open Access Journals (Sweden)

    Amr ElShaer

    2016-04-01

    Full Text Available Human eye is one of the most accessible organs in the body, nonetheless, its physiology and associated precorneal factors such as nasolacrimal drainage, blinking, tear film, tear turnover, and induced lacrimation has significantly decreased the residence time of any foreign substances including pharmaceutical dosage forms. Soft contact lenses are promising delivery devices that can sustain the drug release and prolong residence time by acting as a geometric barrier to drug diffusion to tear fluid. This study investigates experimental parameters such as composition of polymer mixtures, stabilizer and the amount of active pharmaceutical ingredient on the preparation of a polymeric drug delivery system for the topical ocular administration of Prednisolone. To achieve this goal, prednisolone-loaded poly (lactic-co-glycolic acid (PLGA nanoparticles were prepared by single emulsion solvent evaporation method. Prednisolone was quantified using a validated high performance liquid chromatography (HPLC method. Nanoparticle size was mostly affected by the amount of co-polymer (PLGA used whereas drug load was mostly affected by amount of prednisolone (API used. Longer homogenization time along with higher amount of API yielded the smallest size nanoparticles. The nanoparticles prepared had an average particle size of 347.1 ± 11.9 nm with a polydispersity index of 0.081. The nanoparticles were then incorporated in the contact lens mixture before preparing them. Clear and transparent contact lenses were successfully prepared. When the nanoparticle (NP-loaded contact lenses were compared with control contact lenses (unloaded NP contact lenses, a decrease in hydration by 2% (31.2% ± 1.25% hydration for the 0.2 g loaded NP contact lenses and light transmission by 8% (unloaded NP contact lenses 94.5% NP 0.2 g incorporated contact lenses 86.23%. The wettability of the contact lenses remained within the desired value (<90 °C even upon incorporation of the NP. NP

  11. Delivery strategies to control inflammatory response: Modulating M1-M2 polarization in tissue engineering applications

    OpenAIRE

    Alvarez, Mario Moisés; Liu, Julie C.; Santiago, Grissel Trujillo-de; Cha, Byung-Hyun; Vishwakarma, Ajaykumar; Ghaemmaghami, Amir; Khademhosseini, Ali

    2016-01-01

    Macrophages are key players in many physiological scenarios including tissue homeostasis. In response to injury, typically the balance between macrophage sub-populations shifts from an M1 phenotype (pro-inflammatory) to an M2 phenotype (anti-inflammatory). In tissue engineering scenarios, after implantation of any device, it is desirable to exercise control on this M1-M2 progression and to ensure a timely and smooth transition from the inflammatory to the healing stage. In this review, we bri...

  12. Active and Reactive Power Control Strategy for Grid-Connected Six-Phase Generator by Using Multi-Modular Matrix Converters

    Directory of Open Access Journals (Sweden)

    David Caballero

    2016-12-01

    Full Text Available This paper proposes an active and reactive power control strategy based on predictive control approaches applied to gridconnected renewable energy systems. To accomplish this a multi-modular matrix converter topologies are used in combination with a simple but efficient grid synchronization strategy. The theoretical performance analysis is performed considering a six-phase wind energy generator system interconnected with the grid. Results based on a MATLAB/Simulink simulation environment are discussed and the most relevant characteristics of the proposed control technique are highlighted considering the total harmonic distortion and the mean squared error as a parameters of performance.

  13. The effect of prophylactic intravenous tranexamic acid on blood loss after vaginal delivery in women at low risk of postpartum haemorrhage: a double-blind randomised controlled trial.

    Science.gov (United States)

    Mirghafourvand, Mojgan; Mohammad-Alizadeh, Sakineh; Abbasalizadeh, Fatemeh; Shirdel, Mina

    2015-02-01

    To determine the effect of prophylactic tranexamic acid (TA) on calculated and measured blood loss after vaginal delivery in women at low risk of postpartum haemorrhage. In this double-blind randomised controlled trial, 120 women with a singleton pregnancy were randomly allocated to receive either one gram intravenous TA or placebo in addition to 10 IU oxytocin after delivery of the fetus. Calculated blood loss was determined based on haematocrit before delivery and 12-24 h postdelivery. The quantity of blood loss was measured during two time periods: from delivery of the fetus to placental expulsion and from placental expulsion to the end of the second hour after childbirth. The mean (SD) calculated total blood loss (519 (320) vs 659 (402) mL, P = 0.036) and measured blood loss from placental delivery to 2 h postpartum (69 (39) vs 108 (53) mL, P  1000 mL was lower in the TA group (7% vs 18%, P = 0.048). Prophylactic TA reduces blood loss after vaginal delivery in women with a low risk of postpartum haemorrhage. The prophylactic use of TA may reduce blood loss complications and enhance maternal health. © 2015 The Royal Australian and New Zealand College of Obstetricians and Gynaecologists.

  14. The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer

    Directory of Open Access Journals (Sweden)

    Zhu Guo-Pei

    2011-01-01

    Full Text Available Abstract Background High-precision radiation therapy techniques such as IMRT or sterotactic radiosurgery, delivers more complex treatment fields than conventional techniques. The increased complexity causes longer dose delivery times for each fraction. The purpose of this work is to explore the radiobiologic effect of prolonged fraction delivery time on tumor response and survival in vivo. Methods 1-cm-diameter Lewis lung cancer tumors growing in the legs of C57BL mice were used. To evaluate effect of dose delivery prolongation, 18 Gy was divided into different subfractions. 48 mice were randomized into 6 groups: the normal control group, the single fraction with 18 Gy group, the two subfractions with 30 min interval group, the seven subfractions with 5 min interval group, the two subfractions with 60 min interval group and the seven subfractions with 10 min interval group. The tumor growth tendency, the tumor growth delay and the mice survival time were analyzed. Results The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P 0.05. Compared to the group with single fraction of 18 Gy, the groups with prolonged delivery time shorten the mice survival time while there was no significant difference between the groups with prolonged delivery time 30 min and the groups with prolonged delivery time 60 min. Conclusions The prolonged delivery time with same radiation dose shorten the tumor growth delay and survival time in the mice implanted with Lewis lung cancer. The anti-tumor effect decreased with elongation of the total interfractional time.

  15. Performance Improvement of Sensorless Vector Control for Induction Motor Drives Fed by Matrix Converter Using Nonlinear Model and Disturbance Observer

    DEFF Research Database (Denmark)

    Lee, Kyo-Beum; Blaabjerg, Frede

    2004-01-01

    device is corrected by a new matrix converter modeling. The lumped disturbances such as parameter variation and load disturbance of the system are estimated by the radial basis function network (RBFN). An adaptive observer is also employed to bring better responses at the low speed operation...

  16. Coordinated Control for Flywheel Energy Storage Matrix Systems for Wind Farm Based on Charging/Discharging Ratio Consensus Algorithms

    DEFF Research Database (Denmark)

    Cao, Qian; Song, Y. D.; Guerrero, Josep M.

    2016-01-01

    This paper proposes a distributed algorithm for coordination of flywheel energy storage matrix system (FESMS) cooperated with wind farm. A simple and distributed ratio consensus algorithm is proposed to solve FESMS dispatch problem. The algorithm is based on average consensus for both undirected...

  17. Study on Chitosan-Polyvinyl Alcohol Inter polymeric ph-Responsive Hydrogels for Controlled Drug Delivery

    International Nuclear Information System (INIS)

    Abdel-Bary, E.M.; El-Sherbiny, I.M.; Abdelaal, M.Y.; Abdel-Razik, E.A.

    2005-01-01

    Two series of ph-responsive biodegradable interpenetrating polymeric (IPN) hydrogels composed of chitosan and poly(vinyl alcohol) (PVA) were prepared for controlled drug release investigations. The first series was chemically crosslinked with different concentrations of glutaraldehyde as a crosslinked and the second series was crosslinked by gamma-radiation. Degree of crosslinking has been controlled by the concentration of crosslinked as well as by gamma irradiation dose. The equilibrium swelling -reflecting the degree of crosslinks - were carried out for the gels at 37 degree C in buffer solutions of ph 2.1 and 7.4 (simulated gastric and intestinal fluids respectively). 5-fluorouracil (5- FU) was entrapped, as a model therapeutic agent, in the hydrogels and equilibrium-swelling studies were carried out for the drug-entrapped gels at 37 degree C. The in-vitro release profiles of the drug were established at 37 degree C in ph 2.1 and 7.4. FT-IR was employed to investigate the structural changes of the gels with different degrees of crosslinking

  18. Spatiotemporal control over molecular delivery and cellular encapsulation from electropolymerized micro- and nanopatterned surfaces.

    Science.gov (United States)

    Stern, Eric; Jay, Steven M; Demento, Stacey L; Murelli, Ryan P; Reed, Mark A; Malinski, Tadeusz; Spiegel, David A; Mooney, David J; Fahmy, Tarek M

    2009-07-13

    Bioactive, patterned micro- and nanoscale surfaces that can be spatially engineered for three-dimensional ligand presentation and sustained release of signaling molecules represent a critical advance for the development of next-generation diagnostic and therapeutic devices. Lithography is ideally suited to patterning such surfaces due to its precise, easily scalable, high-throughput nature; however, to date polymers patterned by these techniques have not demonstrated the capacity for sustained release of bioactive agents. We demonstrate here a class of lithographically-defined, electropolymerized polymers with monodisperse micro- and nanopatterned features capable of sustained release of bioactive drugs and proteins. We show that precise control can be achieved over the loading capacity and release rates of encapsulated agents and illustrate this aspect using a fabricated surface releasing a model antigen (ovalbumin) and a cytokine (interleukin-2) for induction of a specific immune response. We further demonstrate the ability of this technique to enable three-dimensional control over cellular encapsulation. The efficacy of the described approach is buttressed by its simplicity, versatility, and reproducibility, rendering it ideally suited for biomaterials engineering.

  19. Evaluation of Enhanced Condensational Growth (ECG) for Controlled Respiratory Drug Delivery in a Mouth-Throat and Upper Tracheobronchial Model

    Science.gov (United States)

    Hindle, Michael; Longest, P. Worth

    2010-01-01

    Purpose The objective of this study is to evaluate the effects of enhanced condensational growth (ECG), as a novel inhalation drug delivery method, on nano-aerosol deposition in a mouth-throat (MT) and upper tracheobronchial (TB) model using in vitro experiments and computational fluid dynamics (CFD) simulations. Methods Separate streams of nebulized nano-aerosols and saturated humidified air (39°C—ECG; 25°C—control) were combined as they were introduced into a realistic MT-TB geometry. Aerosol deposition was determined in the MT, generations G0–G2 (trachea—lobar bronchi) and G3–G5 and compared to CFD simulations. Results Using ECG conditions, deposition of 560 and 900 nm aerosols was low in the MT region of the MT-TB model. Aerosol drug deposition in the G0–G2 and G3–G5 regions increased due to enhanced condensational growth compared to control. CFD-predicted depositions were generally in good agreement with the experimental values. Conclusions The ECG platform appears to offer an effective method of delivering nano-aerosols through the extrathoracic region, with minimal deposition, to the tracheobronchial airways and beyond. Aerosol deposition is then facilitated as enhanced condensational growth increases particle size. Future studies will investigate the effects of physio-chemical drug properties and realistic inhalation profiles on ECG growth characteristics. PMID:20454837

  20. Synthetic Geopolymers for Controlled Delivery of Oxycodone: Adjustable and Nanostructured Porosity Enables Tunable and Sustained Drug Release

    Science.gov (United States)

    Forsgren, Johan; Pedersen, Christian; Strømme, Maria; Engqvist, Håkan

    2011-01-01

    In this article we for the first time present a fully synthetic mesoporous geopolymer drug carrier for controlled release of opioids. Nanoparticulate precursor powders with different Al/Si-ratios were synthesized by a sol-gel route and used in the preparation of different geopolymers, which could be structurally tailored by adjusting the Al/Si-ratio and the curing temperatures. In particular, it was shown that the pore sizes of the geopolymers decreased with increasing Al/Si ratio and that completely mesoporous geopolymers could be produced from precursor particles with the Al/Si ratio 2∶1. The mesoporosity was shown to be associated with a sustained and linear in vitro release profile of the opioid oxycodone. A clinically relevant release period of about 12 h was obtained by adjusting the size of the pellets. The easily fabricated and tunable geopolymers presented in this study constitute a novel approach in the development of controlled release formulations, not only for opioids, but whenever the clinical indication is best treated with a constant supply of drugs and when the mechanical stability of the delivery vehicle is crucial. PMID:21423616

  1. Synthetic geopolymers for controlled delivery of oxycodone: adjustable and nanostructured porosity enables tunable and sustained drug release.

    Directory of Open Access Journals (Sweden)

    Johan Forsgren

    2011-03-01

    Full Text Available In this article we for the first time present a fully synthetic mesoporous geopolymer drug carrier for controlled release of opioids. Nanoparticulate precursor powders with different Al/Si-ratios were synthesized by a sol-gel route and used in the preparation of different geopolymers, which could be structurally tailored by adjusting the Al/Si-ratio and the curing temperatures. In particular, it was shown that the pore sizes of the geopolymers decreased with increasing Al/Si ratio and that completely mesoporous geopolymers could be produced from precursor particles with the Al/Si ratio 2:1. The mesoporosity was shown to be associated with a sustained and linear in vitro release profile of the opioid oxycodone. A clinically relevant release period of about 12 h was obtained by adjusting the size of the pellets. The easily fabricated and tunable geopolymers presented in this study constitute a novel approach in the development of controlled release formulations, not only for opioids, but whenever the clinical indication is best treated with a constant supply of drugs and when the mechanical stability of the delivery vehicle is crucial.

  2. Encapsulation and controlled release of retinol from silicone particles for topical delivery.

    Science.gov (United States)

    Wyatt Shields, C; White, John P; Osta, Erica G; Patel, Jerishma; Rajkumar, Shashank; Kirby, Nickolas; Therrien, Jean-Philippe; Zauscher, Stefan

    2018-03-28

    Retinol, a derivative of vitamin A, is a ubiquitous compound used to treat acne, reduce wrinkles and protect against conditions like psoriasis and ichthyosis. While retinol is used as the primary active ingredient (AI) in many skin care formulations, its efficacy is often limited by an extreme sensitivity to degrade and toxicity at high concentrations. While microencapsulation is an appealing method to help overcome these issues, few microencapsulation strategies have made a major translational impact due to challenges with complexity, cost, limited protection of the AI and poor control of the release of the AI. We have developed a class of silicone particles that addresses these challenges for the encapsulation, protection and controlled release of retinol and other hydrophobic compounds. The particles are prepared by the sol-gel polymerization of silane monomers, which enables their rapid and facile synthesis at scale while maintaining a narrow size distribution (i.e., CV 85%), (ii) protect retinol from degradation (yielding a half-life 9× greater than unencapsulated retinol) and (iii) slowly release retinol over several hours (at rates from 0.14 to 0.67 μg cm -2  s -1/2 ). To demonstrate that the controlled release of retinol from the particles can reduce irritation, we performed a double blind study on human subjects and found that formulations containing our particles were 12-23% less irritating than identical formulations containing Microsponge® particles (an industry standard by Amcol, Inc.). To show that the silicone particles can elicit a favorable biological response, similar to the Microsponge® particles, we applied both formulations to reconstructed human epidermal tissues and found an upregulation of keratin 19 (K19) and a downregulation of K10, indicating that the reduced irritation observed in the human study was not caused by reduced activity. We also found a decrease in the production of interleukin-1α (IL-1α) compared to formulations

  3. The "RESEAU MATER": An efficient infection control for endometritis, but not for urinary tract infection after vaginal delivery.

    Science.gov (United States)

    Ayzac, Louis; Caillat-Vallet, Emmanuelle; Girard, Raphaële; Berland, Michel

    "RESEAU MATER" is useful to monitor nosocomial infections in maternity and contributes to the decreasing trend of it, since its implementation. Specifically, this network demonstrates its efficiency in the control of endometritis following vaginal deliveries, but not in the control of urinary tract infections. The aim of this study is to determine whether the difference between the control of endometritis and of urinary tract infection could be explained by an unsuitable regression model or by an unsuitable care policy concerning urinary cares. This study includes (1) the analysis of historic data of the network and (2) the description of French guidelines for maternity cares and available evaluations, concerning endometritis and urinary tract infection prevention. Univariate and multivariate odds ratios (ORs) were calculated for the total study period of 1999-2013, for these infections and their risk factors. The endometritis frequency is decreasing, in association with no significant evolution of associated risk factors, but urinary tract infection frequency is constant, in association with a increasing trend of its risk factors such as intermittent catheterization and epidural analgesia. In French guidelines, all preventive measures against endometritis are clearly broadcasted by all field operators, and repeated audits have reinforced the control of their application. But preventive measures against urinary tract infection seem to be broadcasted exclusively in the circle of infection prevention agencies and not in the obstetrics societies or in the Health Ministry communication. Urinary tract infection prevention requires a clearer public and professional policy in favor of a more efficient urinary cares, with a specific target to maternity. Copyright © 2016 King Saud Bin Abdulaziz University for Health Sciences. Published by Elsevier Ltd. All rights reserved.

  4. Controlling the particle size of interpolymer complexes through host-guest interaction for drug delivery.

    Science.gov (United States)

    Chen, Yan; Pang, Yan; Wu, Jieli; Su, Yue; Liu, Jinyao; Wang, Ruibin; Zhu, Bangshang; Yao, Yefeng; Yan, Deyue; Zhu, Xinyuan; Chen, Qun

    2010-06-01

    A new method to adjust the particle size of interpolymer complexes has been developed by introduction of host-guest interaction into the dilute aqueous solution of poly(acrylic acid) (PAA) and poly(ethylene glycol) (PEG). Because of the cooperative hydrogen-bonding interaction, PAA can form the interpolymer complexes with PEG. Putting beta-cyclodextrin (beta-CD) into dilute PAA/PEG aqueous solution, the competition between host-guest and hydrogen-bonding interactions happens. The beta-CD/PAA/PEG ternary systems have been well characterized by ultraviolet-visible absorption spectroscopy (UV-vis), dynamic light scattering (DLS), transmission electron microscopy (TEM), diffusion NMR spectroscopy, attenuated total reflectance-Fourier transform infrared (ATR-FTIR), and solid-state (13)C NMR spectroscopy. The results indicate that the hydrophobic cavity of beta-CD is threaded by linear polymers so that the hydrophilicity of PAA/PEG interpolymer complexes is improved greatly. Adjusting the amounts of beta-CD, the particle size of the interpolymer complexes can be readily controlled. The low cytotoxicity of various beta-CD/PAA/PEG ternary complexes has been confirmed using the MTT assay in COS-7 cell line. Doxorubicin (DOX), an anticancer drug, has been encapsulated into the beta-CD/PAA/PEG ternary complexes. The DOX-loaded beta-CD/PAA/PEG ternary complexes have been analyzed by confocal laser scanning microscopy (CLSM), flow cytometry analysis, and the MTT assay against human cervical carcinoma cell (Hela). The results indicate that beta-CD/PAA/PEG ternary complexes with controlled particle size could be used as safe and promising drug carriers.

  5. Determination and Comparison of Neonatal Complications in Painless Epidural Delivery and without Pain Control Qom Izadi Hospital during the Years 2004-5

    Directory of Open Access Journals (Sweden)

    N. Tashakorinia

    2007-04-01

    Full Text Available Background and objectives Provision of standard childbirth facilities has been considered as an important healthcare issue for a long time. The physical and psychological states of mothers are important factors determining the fate of delivery. Therefore, several programs have been established to decrease the mother-child mortality rates and the complications of delivery. One of the most common approaches for controlling the pain of delivery is application of local anesthesia such as epidural, spinal, or a combination of these methods. It has been shown that complications of epidural anesthesia are less than other methods of local anesthesia employed for the painless delivery. In this study, a comparison is made between two groups of 80 neonates delivered by either NVD or EU.Methods A form was designed for collection of data including Apgar score at first minute, need for CPR, NICU admission, FHR variability, breast feeding time, duration of hospital stay, and neonatal reflexes. The data were analyzed by chi-square and fisher tests using SPSS software.Results There was no significant difference between the neonates born by EA or NVD at the 95% confidence level.Conclusion Based on these findings it could be concluded that epidural anesthesia for delivery does not lead to neonatal complications more than that of NVD without pain control. Therefore, this method could be recommended to mothers, who choose elective cesarean section to avoid the pain of childbirth.Keywords: Heart Rate, Fetal ; Cardiopulmonary Resuscitation ; Intensive care, Neonatal; Anesthesia, Epidural

  6. Polymeric gels for intravaginal drug delivery.

    Science.gov (United States)

    Cook, Michael T; Brown, Marc B

    2018-01-28

    Intravaginal drug delivery can elicit a local effect, or deliver drugs systemically without hepatic first pass metabolism. There are a number of emerging areas in intravaginal drug delivery, but the vagina is a challenging route of administration, due to the clearance mechanisms present which result in poor retention of dosage forms, and the potential for irritation and other adverse reactions. Gel formulations are desirable due to the ease of application, spreading and that they cause little to no discomfort to the patient. However, these dosage forms, in particular, are poorly retained and traditional gels typically have little control over drug release rates. This has led to a large number of studies on improving the retention of vaginal gels and modulating the controlled release of drugs from the gel matrix. This review outlines the anatomy and physiology of the vagina, focussing on areas relevant to drug delivery. Medical applications of vaginally administered medicines is then discussed, followed by an overview of polymeric gels in intravaginal drug delivery. The sensorial properties of intravaginal gels, and how these relate to user compliance are also summarised. Finally, some important barriers to marketing approval are described. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Matrix thermalization

    Energy Technology Data Exchange (ETDEWEB)

    Craps, Ben [Theoretische Natuurkunde, Vrije Universiteit Brussel (VUB), and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Evnin, Oleg [Department of Physics, Faculty of Science, Chulalongkorn University, Thanon Phayathai, Pathumwan, Bangkok 10330 (Thailand); Theoretische Natuurkunde, Vrije Universiteit Brussel (VUB), and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium); Nguyen, Kévin [Theoretische Natuurkunde, Vrije Universiteit Brussel (VUB), and International Solvay Institutes, Pleinlaan 2, B-1050 Brussels (Belgium)

    2017-02-08

    Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.

  8. Quality Control of Compounded Crystalloid Fluids for Intravenous Delivery to Horses.

    Science.gov (United States)

    Magnusson, C B; Poulsen, K P; Budde, J A; Hartmann, F A; Aulik, N A; Raabis, S M; Moreira, A S D; Darien, B J; Peek, S F

    2018-01-01

    Periodic lack of availability and high cost of commercially produced isotonic fluids for intravenous (IV) use in horses have increasingly led to use of home-made or commercially compound fluids by veterinarians. Data regarding the quality control and safety of compounded fluids would be of benefit to equine veterinarians. To compare electrolyte concentrations, sterility, and endotoxin contamination of commercially available fluids to 2 forms of compounded isotonic crystalloid fluids intended for IV use in horses. Prospective study. Two methods of preparing compounded crystalloids formulated to replicate commercial Plasma-Lyte A (Abbott, Chicago, IL) were compared. One formulation was prepared by a hand-mixed method involving chlorinated drinking water commonly employed by equine practitioners, and the other was prepared by means of ingredients obtained from a commercial compounding pharmacy. The variables for comparison were electrolyte concentrations, sterility, and presence of endotoxin contamination. Electrolyte concentrations were consistent within each product but different between types of fluids (P fluids had significantly more bacterial contamination compared to commercial Plasma-Lyte A (P = 0.0014). One of the hand-mixed fluid samples had detectable endotoxin contamination. Chlorinated drinking water is not an acceptable source of water to compound isotonic fluids for IV administration. Equine practitioners should be aware of this risk and obtain the informed consent of their clients. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  9. Calcium pectinate-fenugreek seed mucilage mucoadhesive beads for controlled delivery of metformin HCl.

    Science.gov (United States)

    Nayak, Amit Kumar; Pal, Dilipkumar; Das, Sabinesh

    2013-07-01

    Calcium pectinate-fenugreek seed mucilage (FSM) mucoadhesive beads containing metformin HCl was developed through ionic-gelation. Effects of pectin and FSM amounts on drug encapsulation efficiency (DEE) and cumulative drug release at 10h (R10 h) were optimized using 3(2) factorial design. The DEE (%) was within the range of 63.16 ± 2.88 to 96.03 ± 4.67% (w/w). The in vitro drug release from these beads (56.64 ± 1.47 to 93.63 ± 4.52% over 10h) was followed controlled-release (zero-order) pattern (R(2)=0.993 to 0.997) with super case-II transport mechanism. The average size of beads was within 1.47 ± 0.14 to 2.08 ± 0.18 mm. The beads were also characterized by SEM and FTIR. The swelling and mucoadhesivity of these beads were influenced by pH of the medium. The optimized beads also exhibited good mucoadhesivity and significant hypoglycemic effect in alloxan-induced diabetic rats over prolonged period after oral administration. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Organic-inorganic hybrid nanoparticles controlled delivery system for anticancer drugs.

    Science.gov (United States)

    Di Martino, Antonio; Guselnikova, Olga A; Trusova, Marina E; Postnikov, Pavel S; Sedlarik, Vladimir

    2017-06-30

    The use of organic-inorganic hybrid nanocarriers for controlled release of anticancer drugs has been gained a great interest, in particular, to improve the selectivity and efficacy of the drugs. In this study, iron oxide nanoparticles were prepared then surface modified via diazonium chemistry and coated with chitosan, and its derivative chitosan-grafted polylactic acid. The purpose was to increase the stability of the nanoparticles in physiological solution, heighten drug-loading capacity, prolong the release, reduce the initial burst effect and improve in vitro cytotoxicity of the model drug doxorubicin. The materials were characterized by DLS, ζ-potential, SEM, TGA, magnetization curves and release kinetics studies. Results confirmed the spherical shape, the presence of the coat and the advantages of using chitosan, particularly its amphiphilic derivative, as a coating agent, thereby surpassing the qualities of simple iron oxide nanoparticles. The coated nanoparticles exhibited great stability and high encapsulation efficiency for doxorubicin, at over 500μg per mg of carrier. Moreover, the intensity of the initial burst was clearly diminished after coating, hence represents an advantage of using the hybrid system over simple iron oxide nanoparticles. Cytotoxicity studies demonstrate the increase in cytotoxicity of doxorubicin when loaded in nanoparticles, indirectly proving the role played by the carrier and its surface properties in cell uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Operative technique at caesarean delivery and risk of complete uterine rupture in a subsequent trial of labour at term. A registry case-control study

    DEFF Research Database (Denmark)

    Thisted, Dorthe L. A.; Mortensen, Laust H.; Hvidman, Lone

    2017-01-01

    Objective: To estimate the relation of single-layer closure at previous caesarean delivery, and other pre-labour and intra-partum risk factors for complete uterine rupture in trial of vaginal birth after a caesarean (TOLAC) at term. Study design: Population-based case-control study. We identified...

  12. Biomaterials and biotechnology: from the discovery of the first angiogenesis inhibitors to the development of controlled drug delivery systems and the foundation of tissue engineering.

    Science.gov (United States)

    Langer, Robert

    2013-09-01

    This paper describes the discovery of the first inhibitors of angiogenesis; the discoveries that