WorldWideScience

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. 3D printed, controlled release, tritherapeutic tablet matrix for advanced anti-HIV-1 drug delivery.

    Science.gov (United States)

    Siyawamwaya, Margaret; du Toit, Lisa C; Kumar, Pradeep; Choonara, Yahya E; Kondiah, Pierre P P D; Pillay, Viness

    2018-04-12

    A 3D-Bioplotter® was employed to 3D print (3DP) a humic acid-polyquaternium 10 (HA-PQ10) controlled release fixed dose combination (FDC) tablet comprising of the anti-HIV-1 drugs, efavirenz (EFV), tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC). Chemical interactions, surface morphology and mechanical strength of the FDC were ascertained. In vitro drug release studies were conducted in biorelevant media followed by in vivo study in the large white pigs, in comparison with a market formulation, Atripla®. In vitro-in vivo correlation of results was undertaken. EFV, TDF and FTC were successfully entrapped in the 24-layered rectangular prism-shaped 3DP FDC with a loading of ∼12.5 mg/6.3 mg/4 mg of EFV/TDF/FTC respectively per printed layer. Hydrogen bonding between the EFV/TDF/FTC and HA-PQ10 was detected which was indicative of possible drug solubility enhancement. The overall surface of the tablet exhibited a fibrilla structure and the 90° inner pattern was determined to be optimal for 3DP of the FDC. In vitro and in vivo drug release profiles from the 3DP FDC demonstrated that intestinal-targeted and controlled drug release was achieved. A 3DP FDC was successfully manufactured with the aid of a 3D-Bioplotter in a single step process. The versatile HA-PQ10 entrapped all drugs and achieved an enhanced relative bioavailability of EFV, TDF, and FTC compared to the market formulation for potentially enhanced HIV treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Alginate/hydrophobic HPMC (60M particulate systems: new matrix for site-specific and controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Kajal Ghosal

    2011-12-01

    Full Text Available This study aimed to obtain site-specific and controlled drug release particulate systems. Some particulates were prepared using different concentrations of sodium alginate (Na-Alg alone and others were formulated using different proportions of Na-Alg with hydroxypropyl methylcellulose (HPMC stearoxy ether (60M viscosity grade, a hydrophobic form of conventional HPMC, using diclofenac potassium (DP by ion-exchange methods. Beads were characterized by encapsulation efficiency, release profile, swelling, and erosion rate. The suitability of common empirical (zero-order, first-order and Higuchi and semi-empirical (Ritger-Peppas and Peppas-Sahlin models was studied to describe the drug release profile. The Weibull model was also studied. Models were tested by non-linear least-square curve fitting. A general purpose mathematical software (MATLAB was used as an analysis tool. In addition, instead of the widely used linear fitting of log-transformed data, direct fitting was used to avoid any sort of truncation or transformation errors. The release kinetics of the beads indicated a purely relaxation-controlled delivery, referred to as case II transport. Weibull distribution showed a close fit. The release of DP from Na-Alg particulates was complete in 5-6 hours, whereas from Na-Alg hydrophobic HPMC particulate systems, release was sustained up to 10 hours. Hydrophobic HPMC with Na-Alg is an excellent matrix to formulate site-specific and controlled drug release particulate systems.Este estudo teve como objetivo a obtenção de sistemas particulados para a liberação controlada de fármacos em sítios de ação específicos. Algumas partículas foram preparadas utilizando-se diferentes concentrações de alginato de sódio (Na-Alg e outras foram formuladas por diferentes proporções de Na-Alg com estearoxílico éter de hidroxipropilmetilcelulose (HPMC (grau de viscosidade 60M, uma forma hidrofóbica do convencional HPMC, utilizando o diclofenaco de pot

  4. Matrix Metalloproteinase Responsive Delivery of Myostatin Inhibitors.

    Science.gov (United States)

    Braun, Alexandra C; Gutmann, Marcus; Ebert, Regina; Jakob, Franz; Gieseler, Henning; Lühmann, Tessa; Meinel, Lorenz

    2017-01-01

    The inhibition of myostatin - a member of the transforming growth factor (TGF-β) family - drives regeneration of functional skeletal muscle tissue. We developed a bioresponsive drug delivery system (DDS) linking release of a myostatin inhibitor (MI) to inflammatory flares of myositis to provide self-regulated MI concentration gradients within tissues of need. A protease cleavable linker (PCL) - responding to MMP upregulation - is attached to the MI and site-specifically immobilized on microparticle surfaces. The PCL disintegrated in a matrix metalloproteinase (MMP) 1, 8, and particularly MMP-9 concentration dependent manner, with MMP-9 being an effective surrogate biomarker correlating with the activity of myositis. The bioactivity of particle-surface bound as well as released MI was confirmed by luciferase suppression in stably transfected HEK293 cells responding to myostatin induced SMAD phosphorylation. We developed a MMP-responsive DDS for MI delivery responding to inflammatory flare of a diseased muscle matching the kinetics of MMP-9 upregulation, with MMP-9 kinetics matching (patho-) physiological myostatin levels. ᅟ: Graphical Abstract Schematic illustration of the matrix metalloproteinase responsive delivery system responding to inflammatory flares of muscle disease. The protease cleavable linker readily disintegrates upon entry into the diseased tissue, therby releasing the mystatin inhibitor.

  5. Using matrix organization to manage health care delivery organizations.

    Science.gov (United States)

    Allcorn, S

    1990-01-01

    Matrix organization can provide health care organization managers enhanced information processing, faster response times, and more flexibility to cope with greater organization complexity and rapidly changing operating environments. A review of the literature informed by work experience reveals that the use of matrix organization creates hard-to-manage ambiguity and balances of power in addition to providing positive benefits for health care organization managers. Solutions to matrix operating problems generally rely on the use of superior information and decision support systems and extensive staff training to develop attitudes and behavior consistent with the more collegial matrix organization culture. Further improvement in understanding the suitability of matrix organization for managing health care delivery organizations will involve appreciating the impact of partial implementation of matrix organization, temporary versus permanent uses of matrix organization, and the impact of the ambiguity created by dual lines of authority upon the exercise of power and authority.

  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. Biological studies of matrix metalloproteinase sensitive drug delivery systems

    DEFF Research Database (Denmark)

    Johansen, Pia Thermann

    due to severe side effects as a result of drug distribution to healthy tissues. To enhance ecacy of treatment and improve life quality of patients, tumor specific drug delivery strategies, such as liposome encapsulated drugs, which accumulate in tumor tissue, has gained increased attention. Several....... 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...

  8. The Matrix exponential, Dynamic Systems and Control

    DEFF Research Database (Denmark)

    Poulsen, Niels Kjølstad

    The matrix exponential can be found in various connections in analysis and control of dynamic systems. In this short note we are going to list a few examples. The matrix exponential usably pops up in connection to the sampling process, whatever it is in a deterministic or a stochastic setting...... or it is a tool for determining a Gramian matrix. This note is intended to be used in connection to the teaching post the course in Stochastic Adaptive Control (02421) given at Informatics and Mathematical Modelling (IMM), The Technical University of Denmark. This work is a result of a study of the litterature....

  9. Silk-elastin-like protein polymer matrix for intraoperative delivery of an oncolytic vaccinia virus.

    Science.gov (United States)

    Price, Daniel L; Li, Pingdong; Chen, Chun-Hao; Wong, Danni; Yu, Zhenkun; Chen, Nanhai G; Yu, Yong A; Szalay, Aladar A; Cappello, Joseph; Fong, Yuman; Wong, Richard J

    2016-02-01

    Oncolytic viral efficacy may be limited by the penetration of the virus into tumors. This may be enhanced by intraoperative application of virus immediately after surgical resection. Oncolytic vaccinia virus GLV-1h68 was delivered in silk-elastin-like protein polymer (SELP) in vitro and in vivo in anaplastic thyroid carcinoma cell line 8505c in nude mice. GLV-1h68 in SELP infected and lysed anaplastic thyroid cancer cells in vitro equally as effectively as in phosphate-buffered saline (PBS), and at 1 week retains a thousand fold greater infectious plaque-forming units. In surgical resection models of residual tumor, GLV-1h68 in SELP improves tumor control and shows increased viral β-galactosidase expression as compared to PBS. The use of SELP matrix for intraoperative oncolytic viral delivery protects infectious viral particles from degradation, facilitates sustained viral delivery and transgene expression, and improves tumor control. Such optimization of methods of oncolytic viral delivery may enhance therapeutic outcomes. © 2014 Wiley Periodicals, Inc.

  10. Chemotherapeutic drug delivery by tumoral extracellular matrix targeting

    NARCIS (Netherlands)

    Raavé , R.; Kuppevelt, T.H. van; Daamen, W.F.

    2018-01-01

    Systemic chemotherapy is a primary strategy in the treatment of cancer, but comes with a number of limitations such as toxicity and unfavorable biodistribution. To overcome these issues, numerous targeting systems for specific delivery of chemotherapeutics to tumor cells have been designed and

  11. Controlling service delivery in service triads

    NARCIS (Netherlands)

    Iwaarden, van J.; Valk, van der W.; Aalders, L.; Virolainen, V.-M.

    2010-01-01

    Organizations are increasingly sourcing services that are directly delivered to their (end) customers by external providers. Buying organization, supplier and (end) customer operate in a triadic service relationship. In these triads, the buying organization lacks direct control over service delivery

  12. A Candida biofilm-induced pathway for matrix glucan delivery: implications for drug resistance.

    Directory of Open Access Journals (Sweden)

    Heather T Taff

    Full Text Available Extracellular polysaccharides are key constituents of the biofilm matrix of many microorganisms. One critical carbohydrate component of Candida albicans biofilms, β-1,3 glucan, has been linked to biofilm protection from antifungal agents. In this study, we identify three glucan modification enzymes that function to deliver glucan from the cell to the extracellular matrix. These enzymes include two predicted glucan transferases and an exo-glucanase, encoded by BGL2, PHR1, and XOG1, respectively. We show that the enzymes are crucial for both delivery of β-1,3 glucan to the biofilm matrix and for accumulation of mature matrix biomass. The enzymes do not appear to impact cell wall glucan content of biofilm cells, nor are they necessary for filamentation or biofilm formation. We demonstrate that mutants lacking these genes exhibit enhanced susceptibility to the commonly used antifungal, fluconazole, during biofilm growth only. Transcriptional analysis and biofilm phenotypes of strains with multiple mutations suggest that these enzymes act in a complementary fashion to distribute matrix downstream of the primary β-1,3 glucan synthase encoded by FKS1. Furthermore, our observations suggest that this matrix delivery pathway works independently from the C. albicans ZAP1 matrix formation regulatory pathway. These glucan modification enzymes appear to play a biofilm-specific role in mediating the delivery and organization of mature biofilm matrix. We propose that the discovery of inhibitors for these enzymes would provide promising anti-biofilm therapeutics.

  13. 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.

  14. Matrix approach for the design of service delivery systems

    Directory of Open Access Journals (Sweden)

    Dina Davis-Castro

    2017-04-01

    Full Text Available The gradual change that is occurring from a purely functional approach to one of process, is conditioned from outside and from within organizations. The world changes faster, from one to the next decade. The politic-economic, social and technological conditions of the first half of the 20th century in the world in general, and in Latin America in particular, are far from the last 50 years of the 20th century. The number of changes that have occurred in the first 15 years of the 21st century is also immeasurable. There is a close relationship between the speed of technological change and changes in a good measure socioeconomic.  It leads to uncertain ways of planning the organizations.  Insofar as the cycles innovation - development are shortened, there is a gap between the appearance of products with superior performance in the market and the duration of similar goods previously acquired by users. This phenomenon shows a trend in the behavior of customers. Clients tends to request services solutions, rather than on specific products.  This essay examines some of the phenomena that affect the design of processes of services with a matrix approach, Result of research carried out in this field.

  15. 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.

  16. Numerical modelling of transdermal delivery from matrix systems: parametric study and experimental validation with silicone matrices.

    Science.gov (United States)

    Snorradóttir, Bergthóra S; Jónsdóttir, Fjóla; Sigurdsson, Sven Th; Másson, Már

    2014-08-01

    A model is presented for transdermal drug delivery from single-layered silicone matrix systems. The work is based on our previous results that, in particular, extend the well-known Higuchi model. Recently, we have introduced a numerical transient model describing matrix systems where the drug dissolution can be non-instantaneous. Furthermore, our model can describe complex interactions within a multi-layered matrix and the matrix to skin boundary. The power of the modelling approach presented here is further illustrated by allowing the possibility of a donor solution. The model is validated by a comparison with experimental data, as well as validating the parameter values against each other, using various configurations with donor solution, silicone matrix and skin. Our results show that the model is a good approximation to real multi-layered delivery systems. The model offers the ability of comparing drug release for ibuprofen and diclofenac, which cannot be analysed by the Higuchi model because the dissolution in the latter case turns out to be limited. The experiments and numerical model outlined in this study could also be adjusted to more general formulations, which enhances the utility of the numerical model as a design tool for the development of drug-loaded matrices for trans-membrane and transdermal delivery. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

  17. 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.

  18. Computer-controlled 3-D treatment delivery

    International Nuclear Information System (INIS)

    Fraass, Benedick A.

    1995-01-01

    Purpose/Objective: This course will describe the use of computer-controlled treatment delivery techniques for treatment of patients with sophisticated conformal therapy. In particular, research and implementation issues related to clinical use of computer-controlled conformal radiation therapy (CCRT) techniques will be discussed. The possible/potential advantages of CCRT techniques will be highlighted using results from clinical 3-D planning studies. Materials and Methods: In recent years, 3-D treatment planning has been used to develop and implement 3-D conformal therapy treatment techniques, and studies based on these conformal treatments have begun to show the promise of conformal therapy. This work has been followed by the development of commercially-available multileaf collimator and computer control systems for treatment machines. Using these (and other) CCRT devices, various centers are beginning to clinically use complex computer-controlled treatments. Both research and clinical CCRT treatment techniques will be discussed in this presentation. General concepts and requirements for CCRT will be mentioned. Developmental and clinical experience with CCRT techniques from a number of centers will be utilized. Results: Treatment planning, treatment preparation and treatment delivery must be approached in an integrated fashion in order to clinically implement CCRT treatment techniques, and the entire process will be discussed. Various CCRT treatment methodologies will be reviewed from operational, dosimetric, and technical points of view. The discussion will concentrate on CCRT techniques which are likely to see rather wide dissemination over the next several years, including particularly the use of multileaf collimators (MLC), dynamic and segmental conformal therapy, conformal field shaping, and other related techniques. More advanced CCRT techniques, such as the use of individualized intensity modulation of beams or segments, and the use of computer-controlled

  19. Improving the delivery of global tobacco control.

    Science.gov (United States)

    Bitton, Asaf; Green, Carol; Colbert, James

    2011-01-01

    Tobacco control must remain a critical global health priority given the growing burden of tobacco-induced disease in the developing world. Insights from the emerging field of global health delivery suggest that tobacco control could be improved through a systematic, granular analysis of the processes through which it is promoted, implemented, and combated. Using this framework, a critical bottleneck to the delivery of proven health promotion emerges in the role that the tobacco industry plays in promoting tobacco use and blocking effective tobacco-control policies. This "corporate bottleneck" can also be understood as a root cause of massive disease and suffering upon vulnerable populations worldwide, for the goal of maximizing corporate profit. Naming, understanding, and responding to this corporate bottleneck is crucial to the success of tobacco-control policies. Three case studies of tobacco-control policy--South Africa, the Framework Convention on Tobacco Control, and Uruguay--are presented to explore and understand the implications of this analysis. © 2011 Mount Sinai School of Medicine.

  20. Advanced and controlled drug delivery systems in clinical disease management

    NARCIS (Netherlands)

    Brouwers, JRBJ

    1996-01-01

    Advanced and controlled drug delivery systems are important for clinical disease management. In this review the most important new systems which have reached clinical application are highlighted. Microbiologically controlled drug delivery is important for gastrointestinal diseases like ulcerative

  1. Lipid phase control of DNA delivery

    Energy Technology Data Exchange (ETDEWEB)

    Koynova, Rumiana; Wang, Li; Tarahovsky, Yury; MacDonald, Robert C. (NWU)

    2010-01-18

    Cationic lipids form nanoscale complexes (lipoplexes) with polyanionic DNA and can be utilized to deliver DNA to cells for transfection. Here we report the correlation between delivery efficiency of these DNA carriers and the mesomorphic phases they form when interacting with anionic membrane lipids. Specifically, formulations that are particularly effective DNA carriers form phases of highest negative interfacial curvature when mixed with anionic lipids, whereas less effective formulations form phases of lower curvature. Structural evolution of the carrier lipid/DNA complexes upon interaction with cellular lipids is hence suggested as a controlling factor in lipid-mediated DNA delivery. A strategy for optimizing lipofection is deduced. The behavior of a highly effective lipoplex formulation, DOTAP/DOPE, is found to conform to this 'efficiency formula'.

  2. 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.

  3. Preparation and characterization of metoprolol tartrate containing matrix type transdermal drug delivery system.

    Science.gov (United States)

    Malipeddi, Venkata Ramana; Awasthi, Rajendra; Ghisleni, Daniela Dal Molim; de Souza Braga, Marina; Kikuchi, Irene Satiko; de Jesus Andreoli Pinto, Terezinha; Dua, Kamal

    2017-02-01

    The present study aimed to develop matrix-type transdermal drug delivery system (TDDS) of metoprolol tartrate using polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA). The transdermal films were evaluated for physical parameters, Fourier transform infrared spectroscopy analysis (FTIR), differential scanning calorimetry (DSC), in vitro drug release, in vitro skin permeability, skin irritation test and stability studies. The films were found to be tough, non-sticky, easily moldable and possess good tensile strength. As the concentration of PVA was increased, the tensile strength of the films was also increased. Results of FTIR spectroscopy and DSC revealed the absence of any drug-polymer interactions. In vitro release of metoprolol followed zero-order kinetics and the mechanism of release was found to be diffusion rate controlled. In vitro release studies of metoprolol using Keshary-Chein (vertical diffusion cell) indicated 65.5 % drug was released in 24 h. In vitro skin permeation of metoprolol transdermal films showed 58.13 % of the drug was released after 24 h. In vitro skin permeation of metoprolol followed zero-order kinetics in selected formulations. The mechanism of release was found to be diffusion rate controlled. In a 22-day skin irritation test, tested formulation of transdermal films did not exhibit any allergic reactions, inflammation, or contact dermatitis. The transdermal films showed good stability in the 180-day stability study. It can be concluded that the TDDS of MPT can help in bypassing the first-pass effect and will provide patient improved compliance, without sacrificing the therapeutic advantages of the drugs.

  4. 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.

  5. Stimuli-Responsive Liposomes for Controlled Drug Delivery

    KAUST Repository

    Li, Wengang

    2014-01-01

    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

  6. 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.

  7. 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.

  8. CELLULAR CONTROL OF CONNECTIVE TISSUE MATRIX TENSION†

    Science.gov (United States)

    Langevin, Helene M.; Nedergaard, Maiken; Howe, Alan

    2013-01-01

    The biomechanical behavior of connective tissue in response to stretching is generally attributed to the molecular composition and organization of its extracellular matrix. It also is becoming apparent that fibroblasts play an active role in regulating connective tissue tension. In response to static stretching of the tissue, fibroblasts expand within minutes by actively remodeling their cytoskeleton. This dynamic change in fibroblast shape contributes to the drop in tissue tension that occurs during viscoelastic relaxation. We propose that this response of fibroblasts plays a role in regulating extracellular fluid flow into the tissue, and protects against swelling when the matrix is stretched. This article reviews the evidence supporting possible mechanisms underlying this response including autocrine purinergic signaling. We also discuss fibroblast regulation of connective tissue tension with respect to lymphatic flow, immune function and cancer. PMID:23444198

  9. Cellular control of connective tissue matrix tension.

    Science.gov (United States)

    Langevin, Helene M; Nedergaard, Maiken; Howe, Alan K

    2013-08-01

    The biomechanical behavior of connective tissue in response to stretching is generally attributed to the molecular composition and organization of its extracellular matrix. It also is becoming apparent that fibroblasts play an active role in regulating connective tissue tension. In response to static stretching of the tissue, fibroblasts expand within minutes by actively remodeling their cytoskeleton. This dynamic change in fibroblast shape contributes to the drop in tissue tension that occurs during viscoelastic relaxation. We propose that this response of fibroblasts plays a role in regulating extracellular fluid flow into the tissue, and protects against swelling when the matrix is stretched. This article reviews the evidence supporting possible mechanisms underlying this response including autocrine purinergic signaling. We also discuss fibroblast regulation of connective tissue tension with respect to lymphatic flow, immune function, and cancer. Copyright © 2013 Wiley Periodicals, Inc.

  10. CELLULAR CONTROL OF CONNECTIVE TISSUE MATRIX TENSION†

    OpenAIRE

    Langevin, Helene M.; Nedergaard, Maiken; Howe, Alan

    2013-01-01

    The biomechanical behavior of connective tissue in response to stretching is generally attributed to the molecular composition and organization of its extracellular matrix. It also is becoming apparent that fibroblasts play an active role in regulating connective tissue tension. In response to static stretching of the tissue, fibroblasts expand within minutes by actively remodeling their cytoskeleton. This dynamic change in fibroblast shape contributes to the drop in tissue tension that occur...

  11. Modulation and control of matrix converter for aerospace application

    Science.gov (United States)

    Kobravi, Keyhan

    In the context of modern aircraft systems, a major challenge is power conversion to supply the aircraft's electrical instruments. These instruments are energized through a fixed-frequency internal power grid. In an aircraft, the available sources of energy are a set of variable-speed generators which provide variable-frequency ac voltages. Therefore, to energize the internal power grid of an aircraft, the variable-frequency ac voltages should be converted to a fixed-frequency ac voltage. As a result, an ac to ac power conversion is required within an aircraft's power system. This thesis develops a Matrix Converter to energize the aircraft's internal power grid. The Matrix Converter provides a direct ac to ac power conversion. A major challenge of designing Matrix Converters for aerospace applications is to minimize the volume and weight of the converter. These parameters are minimized by increasing the switching frequency of the converter. To design a Matrix Converter operating at a high switching frequency, this thesis (i) develops a scheme to integrate fast semiconductor switches within the current available Matrix Converter topologies, i.e., MOSFET-based Matrix Converter, and (ii) develops a new modulation strategy for the Matrix Converter. This Matrix Converter and the new modulation strategy enables the operation of the converter at a switching-frequency of 40kHz. To provide a reliable source of energy, this thesis also develops a new methodology for robust control of Matrix Converter. To verify the performance of the proposed MOSFET-based Matrix Converter, modulation strategy, and control design methodology, various simulation and experimental results are presented. The experimental results are obtained under operating condition present in an aircraft. The experimental results verify the proposed Matrix Converter provides a reliable power conversion in an aircraft under extreme operating conditions. The results prove the superiority of the proposed Matrix

  12. Controlling the delivery of outsourced services in asymmetrical supply chains

    NARCIS (Netherlands)

    Iwaarden, van J.; Valk, van der W.; Aalders, L.; Brown, S.W.

    2009-01-01

    Services are increasingly outsourced. When outsourced services are directly delivered to the final customer by the supplier, the buying company lacks direct control over the delivery of the service. The purpose of this study is to expand theory on control over service delivery in supply chains. A

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

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Eryun, E-mail: yaney359@126.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Cao, Minglu [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, Yuwei; Hao, Xiaoyuan [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Pei, Shichun; Gao, Jianwei; Wang, Yan [College of Food and Biological Engineering, Qiqihar University, Qiqihar 161006 (China); Zhang, Zhuanfang [College of Chemistry and Chemical Engineering, Qiqihar University, Qiqihar 161006 (China); Zhang, Deqing, E-mail: zhdqing@163.com [College of Materials Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    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.

  14. 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.

  15. A comprehensive in vitro and in vivo evaluation of thiolated matrix tablets as a gastroretentive delivery system.

    Science.gov (United States)

    Senyigit, Zeynep Ay; Vetter, Anja; Guneri, Tamer; Bernkop-Schnürch, Andreas

    2011-08-01

    The aim of this study was to investigate the potential of thiolated matrix tablets for gastroretentive delivery systems. Poly(acrylic acid)-cysteine (PAA-Cys) and chitosan-4-thiobuthylamidine (chitosan-TBA) were evaluated as anionic and cationic thiolated polymers and riboflavin was used as a model drug. Tablets were prepared by direct compression and each formulation was characterized in terms of disintegration, swelling, mucoadhesion, and drug release properties. Thereafter, the gastric residence times of tablets were determined with in vivo study in rats. The resulting PAA-Cys and chitosan-TBA conjugates displayed 172.80 ± 30.33 and 371.11 ± 72.74 µmol free thiol groups, respectively. Disintegration studies demonstrated the stability of thiolated tablets up to 24 h, whereas tablets prepared with unmodified PAA and chitosan disintegrated within a time period of 1 h. Mucoadhesion studies showed that mucoadhesion work of PAA-Cys and chitosan-TBA tablets were 1.341- and 2.139-times higher than unmodified ones. The mucoadhesion times of PAA, PAA-Cys, chitosan, and chitosan-TBA tablets were 1.5 ± 0.5, 21 ± 1, 1 ± 0.5, 17 ± 1 h, respectively. These results confirm the theory that thiol groups react with mucin glycoproteins and form covalent bonds to the mucus layer. Release studies indicated that a controlled release was provided with thiolated tablets up to 24 h. These promising in vitro results of thiolated tablets were proved with in vivo studies. The thiolated tablets showed a gastroretention time up to 6 h, whereas unmodified tablets completely disintegrated within 1 h in rat stomach. Consequently, the study suggests that thiolated matrix tablets might be promising formulations for gastroretentive delivery systems.

  16. A remotely operated drug delivery system with dose control

    KAUST Repository

    Yi, Ying; Kosel, Jü rgen

    2017-01-01

    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

  17. 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.

  18. 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(equivalent to){Z j=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 P i which characterize the machine performance, and means of determining those directions in Z-space which give one independent control over the P i , 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 CM approach is described and used in studying some candidate Quasi-Axisymmetric (QA) stellarator configurations the National Compact Stellarator Experiment 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

  19. 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

  20. Injectable In-Situ Gelling Controlled Release Drug Delivery System

    OpenAIRE

    Kulwant Singh; S. L. HariKumar

    2012-01-01

    The administration of poorly bioavailable drug through parenteral route is regarded the most efficient for drug delivery. Parenteral delivery provides rapid onset even for the drug with narrow therapeutic window, but to maintain the systemic drug level repeated installation are required which cause the patient discomfort. This can be overcome by designing the drug into a system, which control the drug release even through parenteral delivery, which improve patient compliance as well as pharma...

  1. Microencapsulation: A promising technique for controlled drug delivery.

    Science.gov (United States)

    Singh, M N; Hemant, K S Y; Ram, M; Shivakumar, H G

    2010-07-01

    MICROPARTICLES OFFER VARIOUS SIGNIFICANT ADVANTAGES AS DRUG DELIVERY SYSTEMS, INCLUDING: (i) an effective protection of the encapsulated active agent against (e.g. enzymatic) degradation, (ii) the possibility to accurately control the release rate of the incorporated drug over periods of hours to months, (iii) an easy administration (compared to alternative parenteral controlled release dosage forms, such as macro-sized implants), and (iv) Desired, pre-programmed drug release profiles can be provided which match the therapeutic needs of the patient. This article gives an overview on the general aspects and recent advances in drug-loaded microparticles to improve the efficiency of various medical treatments. An appropriately designed controlled release drug delivery system can be a foot ahead towards solving problems concerning to the targeting of drug to a specific organ or tissue, and controlling the rate of drug delivery to the target site. The development of oral controlled release systems has been a challenge to formulation scientist due to their inability to restrain and localize the system at targeted areas of gastrointestinal tract. Microparticulate drug delivery systems are an interesting and promising option when developing an oral controlled release system. The objective of this paper is to take a closer look at microparticles as drug delivery devices for increasing efficiency of drug delivery, improving the release profile and drug targeting. In order to appreciate the application possibilities of microcapsules in drug delivery, some fundamental aspects are briefly reviewed.

  2. The use of thiolated polymers as carrier matrix in oral peptide delivery--proof of concept.

    Science.gov (United States)

    Bernkop-Schnürch, Andreas; Pinter, Yvonne; Guggi, Davide; Kahlbacher, Hermann; Schöffmann, Gudrun; Schuh, Maximilian; Schmerold, Ivo; Del Curto, Maria Dorly; D'Antonio, Mauro; Esposito, Pierandrea; Huck, Christian

    2005-08-18

    It was the aim of this study to develop an oral delivery system for the peptide drug antide. The stability of the therapeutic peptide towards gastrointestinal peptidases was evaluated. The therapeutic agent and the permeation mediator glutathione were embedded in the thiolated polymer chitosan-4-thio-butylamidine conjugate (chitosan-TBA conjugate) and compressed to tablets. Drug release studies were performed in the dissolution test apparatus according to the Pharmacopoeia Europea using the paddle method and demineralized water as release medium. In order to avoid mucoadhesion of these delivery systems already in the oral cavity and oesophagus tablets were coated with a triglyceride. These tablets were orally given to pigs (weight: 50+/-2 kg; Edelschwein Pietrain). Moreover, antide was administered intravenously, subcutaneously and orally in solution. Results showed stability of antide towards pepsin, trypsin and chymotrypsin. In contrast, antide was rapidly degraded by elastase. Consequently a stomach-targeted delivery system was designed. Drug release studies demonstrated an almost zero-order controlled release of antide over 8 h. In vivo studies demonstrated a relative bioavailability of 34.4% for the subcutaneous administration. Oral administration of antide in solution led to no detectable concentrations of the drug in plasma at all. In contrast, administering antide being incorporated in the thiolated polymer resulted in a significant uptake of the peptide. The absolute and relative bioavailability was determined to be 1.1% and 3.2%, respectively.

  3. 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

  4. 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.

  5. 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…

  6. 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

  7. Strategies for Controlled Delivery of Growth Factors and Cells for Bone Regeneration

    Science.gov (United States)

    Vo, Tiffany N.; Kasper, F. Kurtis; Mikos, Antonios G.

    2012-01-01

    The controlled delivery of growth factors and cells within biomaterial carriers can enhance and accelerate functional bone formation. The carrier system can be designed with preprogrammed release kinetics to deliver bioactive molecules in a localized, spatiotemporal manner most similar to the natural wound healing process. The carrier can also act as an extracellular matrix-mimicking substrate for promoting osteoprogenitor cellular infiltration and proliferation for integrative tissue repair. This review discusses the role of various regenerative factors involved in bone healing and their appropriate combinations with different delivery systems for augmenting bone regeneration. The general requirements of protein, cell and gene therapy are described, with elaboration on how the selection of materials, configurations and processing affects growth factor and cell delivery and regenerative efficacy in both in vitro and in vivo applications for bone tissue engineering. PMID:22342771

  8. 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.

  9. Carboxymethyl starch and lecithin complex as matrix for targeted drug delivery: I. Monolithic mesalamine forms for colon delivery.

    Science.gov (United States)

    Mihaela Friciu, Maria; Canh Le, Tien; Ispas-Szabo, Pompilia; Mateescu, Mircea Alexandru

    2013-11-01

    For drugs expected to act locally in the colon, and for successful treatment, a delivery device is necessary, in order to limit the systemic absorption which decreases effectiveness and causes important side effects. Various delayed release systems are currently commercialized; most of them based on pH-dependent release which is sensitive to gastrointestinal pH variation. This study proposes a novel excipient for colon delivery. This new preparation consists in the complexation between carboxymethyl starch (CMS) and Lecithin (L). As opposed to existing excipients, the new complex is pH-independent, inexpensive, and easy to manufacture and allows a high drug loading. FTIR, X-ray, and SEM structural analysis all support the hypothesis of the formation of a complex. By minor variation of the excipient content within the tablet, it is possible to modulate the release time and delivery at specific sites of the gastrointestinal tract. This study opens the door to a new pH-independent delivery system for mesalamine targeted administration. Our novel formulation fits well with the posology of mesalamine, used in the treatment of Inflammatory Bowel Disease (IBD), which requires repeated administrations (1g orally four times a day) to maintain a good quality of life. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. The effects of collagen-rich extracellular matrix on the intracellular delivery of glycol chitosan nanoparticles in human lung fibroblasts.

    Science.gov (United States)

    Yhee, Ji Young; Yoon, Hong Yeol; Kim, Hyunjoon; Jeon, Sangmin; Hergert, Polla; Im, Jintaek; Panyam, Jayanth; Kim, Kwangmeyung; Nho, Richard Seonghun

    2017-01-01

    Recent progress in nanomedicine has shown a strong possibility of targeted therapy for obstinate chronic lung diseases including idiopathic pulmonary fibrosis (IPF). IPF is a fatal lung disease characterized by persistent fibrotic fibroblasts in response to type I collagen-rich extracellular matrix. As a pathological microenvironment is important in understanding the biological behavior of nanoparticles, in vitro cellular uptake of glycol chitosan nanoparticles (CNPs) in human lung fibroblasts was comparatively studied in the presence or absence of type I collagen matrix. Primary human lung fibroblasts from non-IPF and IPF patients (n=6/group) showed significantly increased cellular uptake of CNPs (>33.6-78.1 times) when they were cultured on collagen matrix. To elucidate the underlying mechanism of enhanced cellular delivery of CNPs in lung fibroblasts on collagen, cells were pretreated with chlorpromazine, genistein, and amiloride to inhibit clathrin-mediated endocytosis, caveolae-mediated endocytosis, and macropinocytosis, respectively. Amiloride pretreatment remarkably reduced the cellular uptake of CNPs, suggesting that lung fibroblasts mainly utilize the macropinocytosis-dependent mechanism when interacted with collagen. In addition, the internalization of CNPs was predominantly suppressed by a phosphoinositide 3-kinase (PI3K) inhibitor in IPF fibroblasts, indicating that enhanced PI3K activity associated with late-stage macropinocytosis can be particularly important for the enhanced cellular delivery of CNPs in IPF fibroblasts. Our study strongly supports the concept that a pathological microenvironment which surrounds lung fibroblasts has a significant impact on the intracellular delivery of nanoparticles. Based on the property of enhanced intracellular delivery of CNPs when fibroblasts are made to interact with a collagen-rich matrix, we suggest that CNPs may have great potential as a drug-carrier system for targeting fibrotic lung fibroblasts.

  11. 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...

  12. 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...

  13. Linear Matrix Inequalities in Multirate Control over Networks

    Directory of Open Access Journals (Sweden)

    Ángel Cuenca

    2012-01-01

    Full Text Available This paper faces two of the main drawbacks in networked control systems: bandwidth constraints and timevarying delays. The bandwidth limitations are solved by using multirate control techniques. The resultant multirate controller must ensure closed-loop stability in the presence of time-varying delays. Some stability conditions and a state feedback controller design are formulated in terms of linear matrix inequalities. The theoretical proposal is validated in two different experimental environments: a crane-based test-bed over Ethernet, and a maglev based platform over Profibus.

  14. 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.

  15. Chemistry, manufacturing and controls in passive transdermal drug delivery systems.

    Science.gov (United States)

    Goswami, Tarun; Audett, Jay

    2015-01-01

    Transdermal drug delivery systems (TDDS) are used for the delivery of the drugs through the skin into the systemic circulation by applying them to the intact skin. The development of TDDS is a complex and multidisciplinary affair which involves identification of suitable drug, excipients and various other components. There have been numerous problems reported with respect to TDDS quality and performance. These problems can be reduced by appropriately addressing chemistry, manufacturing and controls requirements, which would thereby result in development of robust TDDS product and processes. This article provides recommendations on the chemistry, manufacturing and controls focusing on the unique technical aspects of TDDS.

  16. How controlled release technology can aid gene delivery.

    Science.gov (United States)

    Jo, Jun-Ichiro; Tabata, Yasuhiko

    2015-01-01

    Many types of gene delivery systems have been developed to enhance the level of gene expression. Controlled release technology is a feasible gene delivery system which enables genes to extend the expression duration by maintaining and releasing them at the injection site in a controlled manner. This technology can reduce the adverse effects by the bolus dose administration and avoid the repeated administration. Biodegradable biomaterials are useful as materials for the controlled release-based gene delivery technology and various biodegradable biomaterials have been developed. Controlled release-based gene delivery plays a critical role in a conventional gene therapy and genetic engineering. In the gene therapy, the therapeutic gene is released from biodegradable biomaterial matrices around the tissue to be treated. On the other hand, the intracellular controlled release of gene from the sub-micro-sized matrices is required for genetic engineering. Genetic engineering is feasible for cell transplantation as well as research of stem cells biology and medicine. DNA hydrogel containing a sequence of therapeutic gene and the exosome including the individual specific nucleic acids may become candidates for controlled release carriers. Technologies to deliver genes to cell aggregates will play an important role in the promotion of regenerative research and therapy.

  17. 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

  18. 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.

  19. 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.

  20. Nanoparticle bioconjugate for controlled cellular delivery of doxorubicin

    Science.gov (United States)

    Sangtani, Ajmeeta; Petryayeva, Eleonora; Wu, Miao; Susumu, Kimihiro; Oh, Eunkeu; Huston, Alan L.; Lasarte-Aragones, Guillermo; Medintz, Igor L.; Algar, W. Russ; Delehanty, James B.

    2018-02-01

    Nanoparticle (NP)-mediated drug delivery offers the potential to overcome limitations of systemic delivery, including the ability to specifically target cargo and control release of NP-associated drug cargo. Doxorubicin (DOX) is a widely used FDA-approved cancer therapeutic; however, multiple side effects limit its utility. Thus, there is wide interest in modulating toxicity after cell delivery. Our goal here was to realize a NP-based DOX-delivery system that can modulate drug toxicity by controlling the release kinetics of DOX from the surface of a hard NP carrier. To achieve this, we employed a quantum dot (QD) as a central scaffold which DOX was appended via three different peptidyl linkages (ester, disulfide, hydrazone) that are cleavable in response to various intracellular conditions. Attachment of a cell penetrating peptide (CPP) containing a positively charged polyarginine sequence facilitates endocytosis of the ensemble. Polyhistidine-driven metal affinity coordination was used to self-assemble both peptides to the QD surface, allowing for fine control over both the ratio of peptides attached to the QD as well as DOX dose delivered to cells. Microplate-based Förster resonance energy transfer assays confirmed the successful ratiometric assembly of the conjugates and functionality of the linkages. Cell delivery experiments and cytotoxicity assays were performed to compare the various cleavable linkages to a control peptide where DOX is attached through an amide bond. The role played by various attachment chemistries used in QD-peptide-drug assemblies and their implications for the rationale in design of NPbased constructs for drug delivery is described here.

  1. Oromucosal multilayer films for tailor-made, controlled drug delivery.

    Science.gov (United States)

    Lindert, Sandra; Breitkreutz, Jörg

    2017-11-01

    The oral mucosa has recently become increasingly important as an alternative administration route for tailor-made, controlled drug delivery. Oromucosal multilayer films, assigned to the monograph oromucosal preparations in the Ph.Eur. may be a promising dosage form to overcome the requirements related to this drug delivery site. Areas covered: We provide an overview of multilayer films as drug delivery tools, and discuss manufacturing processes and characterization methods. We focus on the suitability of characterization methods for particular requirements of multilayer films. A classification was performed covering indication areas and APIs incorporated in multilayer film systems for oromucosal use in order to provide a summary of data published in this field. Expert opinion: The shift in drug development to high molecular weight drugs will influence the field of pharmaceutical development and delivery technologies. For a high number of indication areas, such as hormonal disorders, cardiovascular diseases or local treatment of infections, the flexible layer design of oromucosal multilayer films provides a promising option for tailor-made, controlled delivery of APIs to or through defined surfaces in the oral cavity. However, there is a lack of discriminating or standardized testing methods to assess the quality of multilayer films in a reliable way.

  2. Silk fibroin as an organic polymer for controlled drug delivery

    NARCIS (Netherlands)

    Hofmann, S.; Foo, S.; Rossetti, F.; Textor, M.; Vunjak-Novakovic, G.; Kaplan, D.L.; Merkle, H.P.; Meinel, L.

    2006-01-01

    The pharmaceutical utility of silk fibroin (SF) materials for drug delivery was investigated. SF films were prepared from aqueous solutions of the fibroin protein polymer and crystallinity was induced and controlled by methanol treatment. Dextrans of different molecular weights, as well as proteins,

  3. Polylysine as a vehicle for extracellular matrix-targeted local drug delivery, providing high accumulation and long-term retention within the vascular wall

    NARCIS (Netherlands)

    Sakharov, D.V.; Jie, A.F.H.; Bekkers, M.E.A.; Emeis, J.J.; Rijken, D.C.

    2001-01-01

    We present the first steps in the elaboration of an approach of extracellular matrix-targeted local drug delivery (ECM-LDD), designed to provide a high concentration, ubiquitous distribution, and long-term retention of a drug within the vessel wall after local intravascular delivery. The approach is

  4. 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

  5. A novel pH-responsive interpolyelectrolyte hydrogel complex for the oral delivery of levodopa. Part II: characterization and formulation of an IPEC-based tablet matrix.

    Science.gov (United States)

    Ngwuluka, Ndidi C; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Khan, Riaz A; Pillay, Viness

    2015-03-01

    This study was undertaken in order to apply a synthesized interpolyelectrolyte complex (IPEC) of polymethacrylate and carboxymethylcellulose as a controlled release oral tablet matrix for the delivery of the model neuroactive drug levodopa. The IPEC (synthesized in Part I of this work) was characterized by techniques such as Fourier Transform Infra-Red (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC), Advanced DSC (ADSC), and Scanning Electron Microscopy (SEM). The tablet matrices were formulated and characterized for their drug delivery properties and in vitro drug release. FTIR confirmed the interaction between the two polymers. The IPEC composite generated tablet matrices with a hardness ranging from 19.152-27.590 N/mm and a matrix resilience ranging between 42 and 46%. An IPEC of polymethacrylate and carboxymethylcellulose was indeed an improvement on the inherent properties of the native polymers providing a biomaterial with the ability to release poorly soluble drugs such as levodopa at a constant rate over a prolonged period of time. © 2014 Wiley Periodicals, Inc.

  6. Computer control of the TFTR tritium storage and delivery system

    International Nuclear Information System (INIS)

    Youssef, N.; Phillips, H.; Yemin, L.; Dong, J.; Pierce, C.

    1980-01-01

    The Tritium Storage and Delivery System (TSDS) will deliver to the torus the required tritium gas in precisely controlled injection profiles. This system will utilize advanced Central Instrumentation, Control and Data Acquisition (CICADA) computer-control techniques, in normal and malfunction-recovery modes of operation. The control scheme of the TSDS is built of three main control scenarios. An operating mode defines the permissives, sequence and path of a process during each scenario. The computerized control of the TSDS has four distinct advantages: (1) versatile control with fast response times both for tritium gas generation and for gas injection into the torus; (2) ease of selecting the proper operating modes of a control scenario, (3) ease of operation without disturbing the multiple levels of containment, and (4) simple fast trouble shooting of system malfunction utilizing programmed procedures and on-line diagnosis. The TSDS has both remote nd local control capability

  7. 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)

  8. 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.

  9. Safety and pharmacokinetics of dapivirine delivery from matrix and reservoir intravaginal rings to HIV-negative women.

    Science.gov (United States)

    Nel, Annalene; Smythe, Shanique; Young, Katherine; Malcolm, Karl; McCoy, Clare; Rosenberg, Zeda; Romano, Joseph

    2009-08-01

    Vaginal microbicides for the prevention of HIV transmission may be an important option for protecting women from infection. Incorporation of dapivirine, a lead candidate nonnucleoside reverse transcriptase inhibitor, into intravaginal rings (IVRs) for sustained mucosal delivery may increase microbicide product adherence and efficacy compared with conventional vaginal formulations. Twenty-four healthy HIV-negative women 18-35 years of age were randomly assigned (1:1:1) to dapivirine matrix IVR, dapivirine reservoir IVR, or placebo IVR. Dapivirine concentrations were measured in plasma and vaginal fluid samples collected at sequential time points over the 33-day study period (28 days of IVR use, 5 days of follow-up). Safety was assessed by pelvic/colposcopic examinations, clinical laboratory tests, and adverse events. Both IVR types were safe and well tolerated with similar adverse events observed in the placebo and dapivirine groups. Dapivirine from both IVR types was successfully distributed throughout the lower genital tract at concentrations over 4 logs greater than the EC50 against wild-type HIV-1 (LAI) in MT4 cells. Maximum concentration (Cmax) and area under the concentration-time curve (AUC) values were significantly higher with the matrix than reservoir IVR. Mean plasma concentrations of dapivirine were <2 ng/mL. These findings suggest that IVR delivery of microbicides is a viable option meriting further study.

  10. 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.

  11. 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.

  12. 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.

  13. Lyophilized mucoadhesive-dendrimer enclosed matrix tablet for extended oral delivery of albendazole.

    Science.gov (United States)

    Mansuri, Shakir; Kesharwani, Prashant; Tekade, Rakesh Kumar; Jain, Narendra Kumar

    2016-05-01

    Dendrimers are multifunctional carriers widely employed for delivering drugs in a variety of disease conditions including HIV/AIDS and cancer. Albendazole (ABZ) is a commonly used anthelmintic drug in human as well as veterinary medicine. In this investigation, ABZ was formulated as a "muco-dendrimer" based sustained released tablet. The mucoadhesive complex was synthesized by anchoring chitosan to fifth generation PPI dendrimer (Muco-PPI) and characterized by UV, FTIR, (1)H NMR spectroscopy and electron microscopy. ABZ was entrapped inside Muco-PPI followed by lyophilization and tableting as matrix tablet. A half-life (t1/2) of 8.06±0.15, 8.17±0.47, 11.04±0.73, 11.49±0.92, 12.52±1.04 and 16.9±1.18h was noted for ABZ (free drug), conventional ABZ tablet (F1), conventional ABZ matrix tablet (F2), PPI-ABZ complex, PPI-ABZ matrix tablet (F3) and Muco-PPI-ABZ matrix tablet (F4), respectively. Thus the novel mucoadhesive-PPI based formulation of ABZ (F4) increased the t1/2 of ABZ significantly by almost twofold as compared to the administration of free drug. The in vivo drug release data showed that the Muco-PPI based formulations have a significantly higher Cmax (2.40±0.02μg/mL) compared with orally administered free ABZ (0.19±0.07μg/mL) as well as conventional tablet (0.20±0.05μg/mL). In addition, the Muco-PPI-ABZ matrix tablet displayed increased mean residence time (MRT) and is therefore a potential candidate to appreciably improve the pharmacokinetic profile of ABZ. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. 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.

  15. 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.

  16. 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.

  17. Polymer matrices obtained by ionizing radiation for using in controlled drug delivery systems

    International Nuclear Information System (INIS)

    Martellini, Flavia

    1998-01-01

    Two kinds of controlled drug delivery system were obtained by gamma radiation induced polymerization. One of the system was obtained from an acrylic derivative of acetaminophen (40-hydroxyacetanilide), by copolymerization of 4-(acryloyloxy) acetanilide and N,N-dimethylacrylamide (DMAA) in dimethylformamide solution with 0,16 kGy/h dose rate and 54 Gy dose. The values of reactivity rate, r-D MAA = 0,31 ± 0,02 e r AOA -0,07 ± 0,12, were determined by Fineman-Ross method. The acetaminophen hydrolysis was carried out in alkaline and enzymatic (trypsin) media. Another kind of drug delivery system studied was solvent controlled type, being the drug immobilized in the hydrogel,. The hydrogels prepared by radiation polymerization of acryloyl-L-propine methylester (A-Pro-OMe) with 10 Gy dose, showed thermosensible property, swelling or shrinking in water with decreased or increased temperatures. The hydrogels were obtained with different crosslink density, trimethylolpropane trimethacrylate, and the monomers N, N-dimethyl acrylamide (DMAA) and 2-cyanoethyl acrylate to study the influence of the composition in the drug delivery rate. It was verified that the porous size besides being a characteristic of the matrix composition, it was also temperature dependent (thermosensible). The analgesic drug acetaminophen was immobilized by entrapment and by physical adsorption into the hydrogels matrices for 'in vitro' study. The insulin was immobilized by adsorption for 'in vivo' study. (author)

  18. Construction of a controlled-release delivery system for pesticides using biodegradable PLA-based microcapsules.

    Science.gov (United States)

    Liu, Baoxia; Wang, Yan; Yang, Fei; Wang, Xing; Shen, Hong; Cui, Haixin; Wu, Decheng

    2016-08-01

    Conventional pesticides usually need to be used in more than recommended dosages due to their loss and degradation, which results in a large waste of resources and serious environmental pollution. Encapsulation of pesticides in biodegradable carriers is a feasible approach to develop environment-friendly and efficient controlled-release delivery system. In this work, we fabricated three kinds of polylactic acid (PLA) carriers including microspheres, microcapsules, and porous microcapsules for controlled delivery of Lambda-Cyhalothrin (LC) via premix membrane emulsification (PME). The microcapsule delivery system had better water dispersion than the other two systems. Various microcapsules with a high LC contents as much as 40% and tunable sizes from 0.68 to 4.6μm were constructed by manipulating the process parameters. Compared with LC technical and commercial microcapsule formulation, the microcapsule systems showed a significantly sustained release of LC for a longer period. The LC release triggered by LC diffusion and matrix degradation could be optimally regulated by tuning LC contents and particle sizes of the microcapsules. This multi-regulated release capability is of great significance to achieve the precisely controlled release of pesticides. A preliminary bioassay against plutella xylostella revealed that 0.68μm LC-loaded microcapsules with good UV and thermal stability exhibited an activity similar to a commercial microcapsule formulation. These results demonstrated such an aqueous microcapsule delivery system had a great potential to be further explored for developing an effective and environmentally friendly pesticide-release formulation. Copyright © 2016 Elsevier B.V. All rights reserved.

  19. 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.

  20. A Control Method of Current Type Matrix Converter for Plasma Control Coil Power Supply

    International Nuclear Information System (INIS)

    Shimada, K.; Matsukawa, M.; Kurihara, K.; Jun-ichi Itoh

    2006-01-01

    In exploration to a tokamak fusion reactor, the control of plasma instabilities of high β plasma such as neoclassical tearing mode (NTM), resistive wall mode (RWM) etc., is the key issue for steady-state sustainment. One of the proposed methods to avoid suppressing RWM is that AC current having a phase to work for reduction the RWM growth is generated in a coil (sector coil) equipped spirally on the plasma vacuum vessel. To stabilize RWM, precise and fast real-time feedback control of magnetic field with proper amplitude and frequency is necessary. This implies that an appropriate power supply dedicated for such an application is expected to be developed. A matrix converter as one of power supply candidates for this purpose could provide a solution The matrix converter, categorized in an AC/AC direct converter composed of nine bi-directional current switches, has a great feature that a large energy storage element is unnecessary in comparison with a standard existing AC/AC indirect converter, which is composed of an AC/DC converter and a DC/AC inverter. It is also advantageous in cost and size of its applications. Fortunately, a voltage type matrix converter has come to be available at the market recently, while a current type matrix converter, which is advantageous for fast control of the large-inductance coil current, has been unavailable. On the background above mentioned, we proposed a new current type matrix converter and its control method applicable to a power supply with fast response for suppressing plasma instabilities. Since this converter is required with high accuracy control, the gate control method is adopted to three-phase switching method using middle phase to reduce voltage and current waveforms distortion. The control system is composed of VME-bus board with DSP (Digital Signal Processor) and FPGA (Field Programmable Gate Array) for high speed calculation and control. This paper describes the control method of a current type matrix converter

  1. The Potential of Silk and Silk-Like Proteins as Natural Mucoadhesive Biopolymers for Controlled Drug Delivery.

    Science.gov (United States)

    Brooks, Amanda E

    2015-01-01

    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.

  2. 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.

  3. [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.

  4. 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.

  5. 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...... to existing pain relief methods. (BIRTH 36:1 March 2009)...

  6. Low energy nanoemulsification to design veterinary controlled drug delivery devices

    Directory of Open Access Journals (Sweden)

    Thierry F Vandamme

    2010-10-01

    Full Text Available Thierry F Vandamme, Nicolas Anton, University of Strasbourg, Faculty of Pharmacy, Illkirch Cedex, France; UMR CNRS 7199, Laboratoire de Conception et Application de Molécules Bioactives, équipe de Pharmacie Biogalénique, Illkirch Cedex, France,  This work is selected as Controlled Release Society Outstanding Veterinary Paper Award 2010Abstract: The unique properties of nanomaterials related to structural stability and quantum-scale reactive properties open up a world of possibilities that could be exploited to design and to target drug delivery or create truly microscale biological sensors for veterinary applications. We developed cost-saving and solvent-free nanoemulsions. Formulated with a low-energy method, these nanoemulsions can find application in the delivery of controlled amounts of drugs into the beverage of breeding animals (such as poultry, cattle, pigs or be used for the controlled release of injectable poorly water-soluble drugs.Keywords: nanoemulsion, nanomedicine, low-energy emulsification, veterinary, ketoprofen, sulfamethazine

  7. 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.

  8. Stimuli-Responsive Polymeric Systems for Controlled Protein and Peptide Delivery: Future Implications for Ocular Delivery.

    Science.gov (United States)

    Mahlumba, Pakama; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Pillay, Viness

    2016-07-30

    Therapeutic proteins and peptides have become notable in the drug delivery arena for their compatibility with the human body as well as their high potency. However, their biocompatibility and high potency does not negate the existence of challenges resulting from physicochemical properties of proteins and peptides, including large size, short half-life, capability to provoke immune responses and susceptibility to degradation. Various delivery routes and delivery systems have been utilized to improve bioavailability, patient acceptability and reduce biodegradation. The ocular route remains of great interest, particularly for responsive delivery of macromolecules due to the anatomy and physiology of the eye that makes it a sensitive and complex environment. Research in this field is slowly gaining attention as this could be the breakthrough in ocular drug delivery of macromolecules. This work reviews stimuli-responsive polymeric delivery systems, their use in the delivery of therapeutic proteins and peptides as well as examples of proteins and peptides used in the treatment of ocular disorders. Stimuli reviewed include pH, temperature, enzymes, light, ultrasound and magnetic field. In addition, it discusses the current progress in responsive ocular drug delivery. Furthermore, it explores future prospects in the use of stimuli-responsive polymers for ocular delivery of proteins and peptides. Stimuli-responsive polymers offer great potential in improving the delivery of ocular therapeutics, therefore there is a need to consider them in order to guarantee a local, sustained and ideal delivery of ocular proteins and peptides, evading tissue invasion and systemic side-effects.

  9. Controlled Bioactive Molecules Delivery Strategies for Tendon and Ligament Tissue Engineering using Polymeric Nanofibers.

    Science.gov (United States)

    Hiong Teh, Thomas Kok; Hong Goh, James Cho; Toh, Siew Lok

    2015-01-01

    The interest in polymeric nanofibers has escalated over the past decade given its promise as tissue engineering scaffolds that can mimic the nanoscale structure of the native extracellular matrix. With functionalization of the polymeric nanofibers using bioactive molecules, localized signaling moieties can be established for the attached cells, to stimulate desired biological effects and direct cellular or tissue response. The inherently high surface area per unit mass of polymeric nanofibers can enhance cell adhesion, bioactive molecules loading and release efficiencies, and mass transfer properties. In this review article, the application of polymeric nanofibers for controlled bioactive molecules delivery will be discussed, with a focus on tendon and ligament tissue engineering. Various polymeric materials of different mechanical and degradation properties will be presented along with the nanofiber fabrication techniques explored. The bioactive molecules of interest for tendon and ligament tissue engineering, including growth factors and small molecules, will also be reviewed and compared in terms of their nanofiber incorporation strategies and release profiles. This article will also highlight and compare various innovative strategies to control the release of bioactive molecules spatiotemporally and explore an emerging tissue engineering strategy involving controlled multiple bioactive molecules sequential release. Finally, the review article concludes with challenges and future trends in the innovation and development of bioactive molecules delivery using polymeric nanofibers for tendon and ligament tissue engineering.

  10. 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.

  11. Design of multimodal degradable hydrogels for controlled therapeutic delivery

    Science.gov (United States)

    Kharkar, Prathamesh Madhav

    Hydrogels are of growing interest for the delivery of therapeutics to specific sites in the body. For localized drug delivery, hydrophilic polymeric precursors often are laden with bioactive moieties and then directly injected to the site of interest for in situ gel formation. The release of physically entrapped cargo is dictated by Fickian diffusion, degradation of the drug carrier, or a combination of both. The goal of this work was to design and characterize degradable hydrogel formulations that are responsive to multiple biologically relevant stimuli for degradation-mediated delivery of cargo molecules such as therapeutic proteins, growth factors, and immunomodulatory agents. We began by demonstrating the use of cleavable click linkages formed by Michael-type addition reactions in conjunction with hydrolytically cleavable functionalities for the degradation of injectable hydrogels by endogenous stimuli for controlled protein release. Specifically, the reaction between maleimides and thiols was utilized for hydrogel formation, where thiol selection dictates the degradability of the resulting linkage under thiol-rich reducing conditions. Relevant microenvironments where degradation would occur in vivo include those rich in glutathione (GSH), a tripeptide that is found at elevated concentrations in carcinoma tissues. Degradation of the hydrogels was monitored with rheometry and volumetric swelling measurements. Arylthiol-based thioether succinimide linkages underwent degradation via click cleavage and thiol exchange reaction in the presence of GSH and via ester hydrolysis, whereas alkylthiol-based thioether succinimide linkages only undergo degradation by only ester hydrolysis. The resulting control over the degradation rate within a reducing microenvironment resulted in 2.5 fold differences in the release profile of the model protein, a fluorescently-labeled bovine serum albumin, from dually degradable hydrogels compared to non-degradable hydrogels, where the

  12. Controlling fungal biofilms with functional drug delivery denture biomaterials.

    Science.gov (United States)

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

    2016-04-01

    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 three kinds of polymers, poly(1-vinyl-2-pyrrolidinone) (PNVP), poly(methacrylic acid) (PMAA), and poly(2-hydroxyethyl methacrylate) (PHEMA), through plasma-initiated grafting polymerization. With a grafting yield as low as 2 wt%, the three classes of new functionalized denture materials showed significantly higher drug binding capacities toward miconazole, a widely used antifungal drug, than the original PMMA denture resin control, leading to sustained drug release and potent biofilm-controlling effects against Candida. Among the three classes of functionalized denture materials, PNVP-grafted resin provided the highest miconazole binding capability and the most powerful antifungal and biofilm-controlling activities. Drug binding mechanisms were studied. These results demonstrated the importance of specific interactions between drug molecules and functional groups on biomaterials, shedding lights on future design of CADS-managing denture materials and other related devices for controlled drug delivery. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. 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...... 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...

  14. 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...... 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...

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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...

  20. 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.

  1. 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

  2. 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

  3. 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...

  4. 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. 

  5. Sociocultural Factors Affecting Unplanned Deliveries at Home: A Community-Based Case Control Study.

    Science.gov (United States)

    Catak, Binali; Oner, Can

    2015-01-01

    Unplanned home deliveries can vary with social and cultural factors. The aim of this study was to define the risk factors of unplanned home births. This case control study was conducted in Istanbul, Turkey. The study group was composed of 229 women who had unplanned home delivery. Six factors (presence of health insurance, duration of living in Istanbul, educational status of the woman, the number of individuals living in the household, the age of the woman at the time of current delivery, and the status of having received care prior to delivery) were determined as independent risk factors for unplanned deliveries at home.

  6. Fabrication of silk fibroin nanoparticles for controlled drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Zheng; Chen Aizheng; Li Yi, E-mail: tcliyi@polyu.edu.hk; Hu Junyan; Liu Xuan; Li Jiashen; Zhang Yu; Li Gang; Zheng Zijian [Hong Kong Polytechnic University, Institute of Textiles and Clothing (Hong Kong)

    2012-03-15

    A novel solution-enhanced dispersion by supercritical CO{sub 2} (SEDS) was employed to prepare silk fibroin (SF) nanoparticles. The resulting SF nanoparticles exhibited a good spherical shape, a smooth surface, and a narrow particle size distribution with a mean particle diameter of about 50 nm. The results of X-ray powder diffraction, thermo gravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy analysis of the SF nanoparticles before and after ethanol treatment indicated conformation transition of SF nanoparticles from random coil to {beta}-sheet form and thus water insolubility. The MTS assay also suggested that the SF nanoparticles after ethanol treatment imposed no toxicity. A non-steroidal anti-inflammatory drug, indomethacin (IDMC), was chosen as the model drug and was encapsulated in SF nanoparticles by the SEDS process. The resulting IDMC-SF nanoparticles, after ethanol treatment, possessed a theoretical average drug load of 20%, an actual drug load of 2.05%, and an encapsulation efficiency of 10.23%. In vitro IDMC release from the IDMC-SF nanoparticles after ethanol treatment showed a significantly sustained release over 2 days. These studies of SF nanoparticles indicated the suitability of the SF nanoparticles prepared by the SEDS process as a biocompatible carrier to deliver drugs and also the feasibility of using the SEDS process to reach the goal of co-precipitation of drug and SF as composite nanoparticles for controlled drug delivery.

  7. Fabrication of silk fibroin nanoparticles for controlled drug delivery

    International Nuclear Information System (INIS)

    Zhao Zheng; Chen Aizheng; Li Yi; Hu Junyan; Liu Xuan; Li Jiashen; Zhang Yu; Li Gang; Zheng Zijian

    2012-01-01

    A novel solution-enhanced dispersion by supercritical CO 2 (SEDS) was employed to prepare silk fibroin (SF) nanoparticles. The resulting SF nanoparticles exhibited a good spherical shape, a smooth surface, and a narrow particle size distribution with a mean particle diameter of about 50 nm. The results of X-ray powder diffraction, thermo gravimetry-differential scanning calorimetry, and Fourier transform infrared spectroscopy analysis of the SF nanoparticles before and after ethanol treatment indicated conformation transition of SF nanoparticles from random coil to β-sheet form and thus water insolubility. The MTS assay also suggested that the SF nanoparticles after ethanol treatment imposed no toxicity. A non-steroidal anti-inflammatory drug, indomethacin (IDMC), was chosen as the model drug and was encapsulated in SF nanoparticles by the SEDS process. The resulting IDMC–SF nanoparticles, after ethanol treatment, possessed a theoretical average drug load of 20%, an actual drug load of 2.05%, and an encapsulation efficiency of 10.23%. In vitro IDMC release from the IDMC–SF nanoparticles after ethanol treatment showed a significantly sustained release over 2 days. These studies of SF nanoparticles indicated the suitability of the SF nanoparticles prepared by the SEDS process as a biocompatible carrier to deliver drugs and also the feasibility of using the SEDS process to reach the goal of co-precipitation of drug and SF as composite nanoparticles for controlled drug delivery.

  8. Labile conjugation of a hydrophilic drug to PLA oligomers to modify a drug delivery system: cephradin in a PLAGA matrix.

    Science.gov (United States)

    Ustariz-Peyret, C; Coudane, J; Vert, M; Kaltsatos, V; Boisramené, B

    2000-01-01

    The physical entrapment of a hydrophilic drug within degradable microspheres is generally difficult because of poor entrapment yield and/or fast release, depending on the microsphere fabrication method. In order to counter the effects of drug hydrophilicity, it is proposed to covalently attach the drug to lactic acid oligomers, with the aim of achieving temporary hydrophobization and slower release controlled by the separation of the drug from the degradable link within the polymer matrix. This strategy was tested on microspheres of the antibiotic cephradin. As the prodrug form, the entrapment of the drug was almost quantitative. The prodrug did degrade in an aqueous medium, modelling body fluids, but cleavage did not occur at the drug-oligomer junction and drug molecules bearing two lactyl residual units were released. When the prodrug is entrapped within a PLAGA matrix, no release was observed within the experimental time period. However, data suggest that conjugation via a bond more sensitive to hydrolysis than the main chain PLA ester bonds should make the system work as desired.

  9. No matrix effect in double-blind, placebo-controlled egg challenges in egg allergic children

    NARCIS (Netherlands)

    Libbers, L.; Flokstra-de Blok, B. M. J.; Vlieg-Boerstra, B. J.; van der Heide, S.; van der Meulen, G. N.; Kukler, J.; Kerkhof, M.; Dubois, A. E. J.

    Background Diagnostic and accidental food allergic reactions may be modified by the matrix containing the allergenic food. Previous studies of double-blind, placebo-controlled food challenges (DBPCFCs) with peanut found an effect of the fat content of the challenge matrix on the severity of the

  10. From nano- to macro-scale: nanotechnology approaches for spatially controlled delivery of bioactive factors for bone and cartilage engineering.

    Science.gov (United States)

    Santo, Vítor E; Gomes, Manuela E; Mano, João F; Reis, Rui L

    2012-07-01

    The field of biomaterials has advanced towards the molecular and nanoscale design of bioactive systems for tissue engineering, regenerative medicine and drug delivery. Spatial cues are displayed in the 3D extracellular matrix and can include signaling gradients, such as those observed during chemotaxis. Architectures range from the nanometer to the centimeter length scales as exemplified by extracellular matrix fibers, cells and macroscopic shapes. The main focus of this review is the application of a biomimetic approach by the combination of architectural cues, obtained through the application of micro- and nanofabrication techniques, with the ability to sequester and release growth factors and other bioactive agents in a spatiotemporal controlled manner for bone and cartilage engineering.

  11. 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.

  12. 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

  13. Controlling inclusive cross sections in parton shower + matrix element merging

    International Nuclear Information System (INIS)

    Plaetzer, Simon

    2012-11-01

    We propose an extension of matrix element plus parton shower merging at tree level to preserve inclusive cross sections obtained from the merged and showered sample. Implementing this constraint generates approximate next-to-leading order (NLO) contributions similar to the LoopSim approach. We then show how full NLO, or in principle even higher order, corrections can be added consistently, including constraints on inclusive cross sections to account for yet missing parton shower accuracy at higher logarithmic order. We also show how NLO accuracy below the merging scale can be obtained.

  14. Controlling inclusive cross sections in parton shower + matrix element merging

    Energy Technology Data Exchange (ETDEWEB)

    Plaetzer, Simon

    2012-11-15

    We propose an extension of matrix element plus parton shower merging at tree level to preserve inclusive cross sections obtained from the merged and showered sample. Implementing this constraint generates approximate next-to-leading order (NLO) contributions similar to the LoopSim approach. We then show how full NLO, or in principle even higher order, corrections can be added consistently, including constraints on inclusive cross sections to account for yet missing parton shower accuracy at higher logarithmic order. We also show how NLO accuracy below the merging scale can be obtained.

  15. Tissue inhibitor of matrix metalloproteinases-1 loaded poly(lactic-co-glycolic acid nanoparticles for delivery across the blood–brain barrier

    Directory of Open Access Journals (Sweden)

    Chaturvedi M

    2014-01-01

    Full Text Available Mayank Chaturvedi,1 Yves Molino,2 Bojja Sreedhar,3 Michel Khrestchatisky,4 Leszek Kaczmarek1 1Laboratory of Neurobiology, Nencki Institute, Warsaw, Poland; 2Vect-Horus, Marseille, France; 3Indian Institute of Chemical Technology, Hyderabad, India; 4Aix-Marseille Université, CNRS, NICN, UMR7259, Marseille, France Aim: The aim of this study was to develop poly(lactic-co-glycolic acid (PLGA nanoparticles (NPs for delivery of a protein – tissue inhibitor of matrix metalloproteinases 1 (TIMP-1 – across the blood–brain barrier (BBB to inhibit deleterious matrix metalloproteinases (MMPs. Materials and methods: The NPs were formulated by multiple-emulsion solvent-evaporation, and for enhancing BBB penetration, they were coated with polysorbate 80 (Ps80. We compared Ps80-coated and uncoated NPs for their toxicity, binding, and BBB penetration on primary rat brain capillary endothelial cell cultures and the rat brain endothelial 4 cell line. These studies were followed by in vivo studies for brain delivery of these NPs. Results: Results showed that neither Ps80-coated nor uncoated NPs caused significant opening of the BBB, and essentially they were nontoxic. NPs without Ps80 coating had more binding to endothelial cells compared to Ps80-coated NPs. Penetration studies showed that TIMP-1 NPs + Ps80 had 11.21%±1.35% penetration, whereas TIMP-1 alone and TIMP-1 NPs without Ps80 coating did not cross the endothelial monolayer. In vivo studies indicated BBB penetration of intravenously injected TIMP-1 NPs + Ps80. Conclusion: The study demonstrated that Ps80 coating of NPs does not cause significant toxic effects to endothelial cells and that it can be used to enhance the delivery of protein across endothelial cell barriers, both in vitro and in vivo. Keywords: PLGA nanoparticles, drug delivery, protein delivery, sustained release, brain delivery, BBB penetration, RBCEC culture

  16. Optimal control of large space structures via generalized inverse matrix

    Science.gov (United States)

    Nguyen, Charles C.; Fang, Xiaowen

    1987-01-01

    Independent Modal Space Control (IMSC) is a control scheme that decouples the space structure into n independent second-order subsystems according to n controlled modes and controls each mode independently. It is well-known that the IMSC eliminates control and observation spillover caused when the conventional coupled modal control scheme is employed. The independent control of each mode requires that the number of actuators be equal to the number of modelled modes, which is very high for a faithful modeling of large space structures. A control scheme is proposed that allows one to use a reduced number of actuators to control all modeled modes suboptimally. In particular, the method of generalized inverse matrices is employed to implement the actuators such that the eigenvalues of the closed-loop system are as closed as possible to those specified by the optimal IMSC. Computer simulation of the proposed control scheme on a simply supported beam is given.

  17. 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

  18. 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.

  19. 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.…

  20. 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...

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

    KAUST Repository

    Pirmoradi, Fatemeh Nazly; Ou, Kevin; Jackson, John K.; Letchford, Kevin; Cui, Jing; Wolf, Ki Tae; Graber, Florian; Zhao, Tom; Matsubara, Joanne A.; Burt, Helen; Chiao, Mu; Lin, Liwei

    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

  2. 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…

  3. 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.

  4. 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.

  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. Predictive control strategies for an indirect matrix converter operating at fixed switching frequency

    DEFF Research Database (Denmark)

    Rivera, M.; Nasir, U.; Tarisciotti, L.

    2017-01-01

    The classic model predictive control presents a variable switching frequency which could produce high ripple in the controlled waveforms or resonances in the input filter of the matrix converter, affecting the performance of the system. This paper presents two model predictive control strategies...

  7. 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%.

  8. 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.

  9. Calcium modified edible Canna (Canna edulis L) starch for controlled released matrix

    Science.gov (United States)

    Putri, A. P.; Ridwan, M.; Darmawan, T. A.; Darusman, F.; Gadri, A.

    2017-07-01

    Canna edulis L starch was modified with calcium chloride in order to form controlled released matrix. Present study aim to analyze modified starch characteristic. Four different formulation of ondansetron granules was used to provide dissolution profile of controlled released, two formula consisted of 15% and 30% modified starch, one formula utilized matrix reference standards and the last granules was negative control. Methocel-hydroxypropyl methyl cellulose was used as controlled released matrix reference standards in the third formula. Calcium starch was synthesized in the presence of sodium hydroxide to form gelatinized mass and calcium chloride as the cross linking agent. Physicochemical and dissolution properties of modified starch for controlled released application were investigated. Modified starch has higher swelling index, water solubility and compressibility index. Three of four different formulation of granules provide dissolution profile of controlled released. The profiles indicate granules which employed calcium Canna edulis L starch as matrix are able to resemble controlled drug released profile of matrix reference, however their bigger detain ability lead to lower bioavailability.

  10. 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.

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. Efficient Algorithms for Distributed Control : A Structured Matrix Approach

    NARCIS (Netherlands)

    Rice, J.K.

    2010-01-01

    Distributed systems are all around us, and they are fascinating, and have an enormous potential to improve our lives, if their complexity can be properly harnessed. All scientists and engineers are aware of the great potential of this subject, since we witness fantastic distributed control systems

  17. 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.

  18. 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...

  19. Perinatal outcomes of unplanned out-of-hospital deliveries: a case-control study.

    Science.gov (United States)

    Pasternak, Yael; Wintner, Eliana Muskin; Shechter-Maor, Gil; Pasternak, Yehonatan; Miller, Netanella; Biron-Shental, Tal

    2018-04-01

    To compare the pregnancy and perinatal outcomes of unplanned home or car births vs. in-hospital deliveries. A retrospective, case-control study of women who underwent unplanned out-of-hospital deliveries vs. in-hospital deliveries from 2004 through 2014. Matching was based on gestational age and parity in a ratio of 2:1. There were no significant differences between the groups regarding demographic criteria, prenatal care and delivery complications. Women who delivered out of hospital (n = 90) had significantly fewer cesarean deliveries (1.1 vs. 10.6%; p = 0.05) and operative deliveries (2.2 vs. 13.3%; p = 0.004) in their obstetrical history than did the control group (n = 180). Significantly more newborns delivered out of the hospital had polycythemia (25.6 vs. 1.7%; p unplanned out-of-hospital deliveries tend to have fewer complications in their previous deliveries. Higher rates of polycythemia and hypothermia require attention for neonates born out of the hospital.

  20. Production of bioinspired and rationally designed polymer hydrogels for controlled delivery of therapeutic proteins

    Science.gov (United States)

    Kim, Sung Hye

    Hydrogel systems for controlled delivery therapeutic growth factors have been developed in a wide spectrum of strategies: these systems aim for the release of growth factors via a passive diffusion, electrostatic interaction, degradation of hydrogels, and responsiveness to external stimuli. Heparin, a highly sulfated glycosaminoglycan (GAG), was employed for a targeted delivery system of vascular endothelial growth factor (VEGF) to endothelial cells overexpressing a relevant receptor VEGFR-2. Addition of dimeric VEGF to 4-arm star-shaped poly(ethylene glycol) (PEG) immobilized with low-molecular weight heparin (LMWH) afforded a non-covalently assembled hydrogel via interaction between heparin and VEGF, with storage modulus 10 Pa. The release of VEGF and hydrogel erosion reached maximum 100 % at day 4 in the presence of VEGFR-2 overexpressing pocine aortic endothelial cell (PAE/KDR), while those of 80% were achieved via passive release at day 5 in the presence of PAE cell lacking VEGFR-2 or in the absence of cell, indicating that the release of VEGF was in targeted manner toward cell receptor. The proliferation of PAE/KDR in the presence of [PEG-LMWH/VEGF] hydrogel was greater by ca. 30% at day 4 compared to that of PAE, confirming that the release of VEGF was in response to the cellular demand. The phosphorylation fraction of VEGFR-2 on PAE/KDR was greater in the presence of [PEG-LMWH/VEGF] hydrogel, increasing from 0.568 at day 1 to 0.790 at day 4, whereas it was maintained at 0.230 at day 4 in the presence of [PEG-LMWH] hydrogel. This study has proven that this hydrogel, assembled via bio-inspired non-covalent interaction, liberating VEGFon celluar demand to target cell, eroding upon VEGF release, and triggering endothelial cell proliferation, could be used in multiple applications including targeted delivery and angiogenesis. Heparin has been widely exploited in growth factor delivery systems owing to its ability to bind many growth factors through the flexible

  1. Matrix mechanics and fluid shear stress control stem cells fate in three dimensional microenvironment.

    Science.gov (United States)

    Chen, Guobao; Lv, Yonggang; Guo, Pan; Lin, Chongwen; Zhang, Xiaomei; Yang, Li; Xu, Zhiling

    2013-07-01

    Stem cells have the ability to self-renew and to differentiate into multiple mature cell types during early life and growth. Stem cells adhesion, proliferation, migration and differentiation are affected by biochemical, mechanical and physical surface properties of the surrounding matrix in which stem cells reside and stem cells can sensitively feel and respond to the microenvironment of this matrix. More and more researches have proven that three dimensional (3D) culture can reduce the gap between cell culture and physiological environment where cells always live in vivo. This review summarized recent findings on the studies of matrix mechanics that control stem cells (primarily mesenchymal stem cells (MSCs)) fate in 3D environment, including matrix stiffness and extracellular matrix (ECM) stiffness. Considering the exchange of oxygen and nutrients in 3D culture, the effect of fluid shear stress (FSS) on fate decision of stem cells was also discussed in detail. Further, the difference of MSCs response to matrix stiffness between two dimensional (2D) and 3D conditions was compared. Finally, the mechanism of mechanotransduction of stem cells activated by matrix mechanics and FSS in 3D culture was briefly pointed out.

  2. In vivo evaluation of an oral salmon calcitonin-delivery system based on a thiolated chitosan carrier matrix.

    Science.gov (United States)

    Guggi, Davide; Kast, Constantia E; Bernkop-Schnürch, Andreas

    2003-12-01

    To develop and evaluate an oral delivery system for salmon calcitonin. 2-Iminothiolane was covalently bound to chitosan in order to improve the mucoadhesive and cohesive properties of the polymer. The resulting chitosan-TBA conjugate (chitosan-4-thiobutylamidine conjugate) was homogenized with salmon calcitonin. mannitol, and a chitosan-Bowman-Birk inhibitor conjugate and a chitosan-elastatinal conjugate (6.75 + 0.25 + 1 + 1 + 1). Optionally 0.5% (m/m) reduced glutathione. used as permeation mediator, was added. Each mixture was compressed to 2 mg microtablets and enteric coated with a polymethacrylate. Biofeedback studies were performed in rats by oral administration of the delivery system and determination of the decrease in plasma calcium level as a function of time. Test formulations led to a significant (p thiolated chitosan, chitosan-enzyme-inhibitor conjugates and the permeation mediator glutathione seems to represent a promising strategy for the oral delivery of salmon calcitonin.

  3. Magnetic control of potential microrobotic drug delivery systems: nanoparticles, magnetotactic bacteria and self-propelled microjets

    NARCIS (Netherlands)

    Khalil, I.S.M.; Magdanz, V.; Sanchez, Stefan; Sanchez, S.; Schmidt, O.G.; Abelmann, Leon; Misra, Sarthak

    2013-01-01

    Development of targeted drug delivery systems using magnetic microrobots increases the therapeutic indices of drugs. These systems have to be incorporated with precise motion controllers. We demonstrate closed-loop motion control of microrobots under the influence of controlled magnetic fields.

  4. 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

  5. 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

  6. 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...

  7. Systematically evaluating the impact of diagnosis-related groups (DRGs) on health care delivery: a matrix of ethical implications.

    Science.gov (United States)

    Fourie, Carina; Biller-Andorno, Nikola; Wild, Verina

    2014-04-01

    Swiss hospitals were required to implement a prospective payment system for reimbursement using a diagnosis-related groups (DRGs) classification system by the beginning of 2012. Reforms to a health care system should be assessed for their impact, including their impact on ethically relevant factors. Over a number of years and in a number of countries, questions have been raised in the literature about the ethical implications of the implementation of DRGs. However, despite this, researchers have not attempted to identify the major ethical issues associated with DRGs systematically. To address this gap in the literature, we have developed a matrix for identifying the ethical implications of the implementation of DRGs. It was developed using a literature review, and empirical studies on DRGs, as well as a review and analysis of existing ethics frameworks. The matrix consists of the ethically relevant parameters of health care systems on which DRGs are likely to have an impact; the ethical values underlying these parameters; and examples of specific research questions associated with DRGs to illustrate how the matrix can be applied. While the matrix has been developed in light of the Swiss health care reform, it could be used as a basis for identifying the ethical implications of DRG-based systems worldwide and for highlighting the ethical implications of other kinds of provider payment systems (PPS). Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  8. Conductive polymer nanotube patch for fast and controlled ex vivo transdermal drug delivery.

    Science.gov (United States)

    Nguyen, Thao M; Lee, Sebin; Lee, Sang Bok

    2014-10-01

    To uptake and release hydrophilic model drugs and insulin in a novel conductive polymer (CP) nanotube transdermal patch. The externally controlled transdermal delivery of model drugs and insulin were tested ex vivo and results were compared with CP films. The unique intrinsic properties of CPs provide electrostatic interaction between the model drugs and polymer backbone. When a pulsed potential was applied, the drug delivery release profile mimics that of injection delivery. With a constant potential applied, the release rate constants of the patch system were up to three-times faster than the control (0 V) and released approximately 80% more drug molecules over 24 h. The CP nanotube transdermal patch represents a new and promising drug method, specifically for hydrophilic molecules, which have been a large obstacle for conventional transdermal drug delivery systems.

  9. Extracellular Matrix (ECM) Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair

    Science.gov (United States)

    Park, Sang-Hyug; Kim, Moon Suk; Kim, Young Jick; Choi, Byung Hyune; Lee, Chun Tek; Park, So Ra; Min, Byoung-Hyun

    2016-01-01

    Recombinant human transforming growth factor beta-3 (rhTGF-β3) is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM) membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS) are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs) using western blot and circular dichroism (CD) analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+) rhTGF-β3 EMLDS) in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair. PMID:27258120

  10. Extracellular Matrix (ECM Multilayer Membrane as a Sustained Releasing Growth Factor Delivery System for rhTGF-β3 in Articular Cartilage Repair.

    Directory of Open Access Journals (Sweden)

    Soon Sim Yang

    Full Text Available Recombinant human transforming growth factor beta-3 (rhTGF-β3 is a key regulator of chondrogenesis in stem cells and cartilage formation. We have developed a novel drug delivery system that continuously releases rhTGF-β3 using a multilayered extracellular matrix (ECM membrane. We hypothesize that the sustained release of rhTGF-β3 could activate stem cells and result in enhanced repair of cartilage defects. The properties and efficacy of the ECM multilayer-based delivery system (EMLDS are investigated using rhTGF-β3 as a candidate drug. The bioactivity of the released rhTGF-ß3 was evaluated through chondrogenic differentiation of mesenchymal stem cells (MSCs using western blot and circular dichroism (CD analyses in vitro. The cartilage reparability was evaluated through implanting EMLDS with endogenous and exogenous MSC in both in vivo and ex vivo models, respectively. In the results, the sustained release of rhTGF-ß3 was clearly observed over a prolonged period of time in vitro and the released rhTGF-β3 maintained its structural stability and biological activity. Successful cartilage repair was also demonstrated when rabbit MSCs were treated with rhTGF-β3-loaded EMLDS ((+ rhTGF-β3 EMLDS in an in vivo model and when rabbit chondrocytes and MSCs were treated in ex vivo models. Therefore, the multilayer ECM membrane could be a useful drug delivery system for cartilage repair.

  11. 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.

  12. 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.

  13. 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.

  14. A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC)

    Energy Technology Data Exchange (ETDEWEB)

    Gerard, Karine; Grandhaye, Jean-Pierre; Marchesi, Vincent; Kafrouni, Hanna; Husson, Francois; Aletti, Pierre [Research Center for Automatic Control (CRAN), Nancy University, CNRS, 54516 Vandoeuvre-les-Nancy (France); Department of Medical Physics, Alexis Vautrin Cancer Center, 54511 Vandoeuvre-les-Nancy Cedex (France) and DOSIsoft SA, 94230 Cachan (France); Research Laboratory for Innovative Processes (ERPI), Nancy University, EA 3767, 5400 Nancy Cedex (France); Department of Medical Physics, Alexis Vautrin Cancer Center, 54511 Vandoeuvre-les-Nancy Cedex (France); DOSIsoft SA, 94230 Cachan (France); Research Center for Automatic Control (CRAN), Nancy University, CNRS, 54516 Vandoeuvre-les-Nancy, France and Department of Medical Physics, Alexis Vautrin Cancer Center, 54511 Vandoeuvre-les-Nancy Cedex (France)

    2009-04-15

    The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center ({+-}4% of deviation between the calculated and measured doses) by calculating a control process capability (C{sub pc}) index. The C{sub pc} index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should

  15. A comprehensive analysis of the IMRT dose delivery process using statistical process control (SPC).

    Science.gov (United States)

    Gérard, Karine; Grandhaye, Jean-Pierre; Marchesi, Vincent; Kafrouni, Hanna; Husson, François; Aletti, Pierre

    2009-04-01

    The aim of this study is to introduce tools to improve the security of each IMRT patient treatment by determining action levels for the dose delivery process. To achieve this, the patient-specific quality control results performed with an ionization chamber--and which characterize the dose delivery process--have been retrospectively analyzed using a method borrowed from industry: Statistical process control (SPC). The latter consisted in fulfilling four principal well-structured steps. The authors first quantified the short-term variability of ionization chamber measurements regarding the clinical tolerances used in the cancer center (+/- 4% of deviation between the calculated and measured doses) by calculating a control process capability (C(pc)) index. The C(pc) index was found superior to 4, which implies that the observed variability of the dose delivery process is not biased by the short-term variability of the measurement. Then, the authors demonstrated using a normality test that the quality control results could be approximated by a normal distribution with two parameters (mean and standard deviation). Finally, the authors used two complementary tools--control charts and performance indices--to thoroughly analyze the IMRT dose delivery process. Control charts aim at monitoring the process over time using statistical control limits to distinguish random (natural) variations from significant changes in the process, whereas performance indices aim at quantifying the ability of the process to produce data that are within the clinical tolerances, at a precise moment. The authors retrospectively showed that the analysis of three selected control charts (individual value, moving-range, and EWMA control charts) allowed efficient drift detection of the dose delivery process for prostate and head-and-neck treatments before the quality controls were outside the clinical tolerances. Therefore, when analyzed in real time, during quality controls, they should improve the

  16. 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)

  17. 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.

  18. 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.

  19. 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

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

    KAUST Repository

    Zaher, Amir; Li, S.; Wolf, K. T.; Pirmoradi, F. N.; Yassine, Omar; Lin, L.; Khashab, Niveen M.; Kosel, Jü rgen

    2015-01-01

    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.

  1. 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.

  2. 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.

  3. 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...... 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...

  4. 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...... 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...

  5. 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

  6. 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 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...... 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...

  7. Closed Loop Control of Oxygen Delivery and Oxygen Generation

    Science.gov (United States)

    2017-08-01

    were used for this study and were connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen...connected via a USB cable to allow communication. The ventilator was modified to allow closed loop control of oxygen based on the oxygen saturation...2017-4119, 28 Aug 2017. oximetry (SpO2) and intermittent arterial blood sampling for arterial oxygen tension (partial pressure of oxygen [PaO2]) and

  8. 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

  9. Temporally controlled growth factor delivery from a self-assembling peptide hydrogel and electrospun nanofibre composite scaffold.

    Science.gov (United States)

    Bruggeman, Kiara F; Wang, Yi; Maclean, Francesca L; Parish, Clare L; Williams, Richard J; Nisbet, David R

    2017-09-21

    Tissue-specific self-assembling peptide (SAP) hydrogels designed based on biologically relevant peptide sequences have great potential in regenerative medicine. These materials spontaneously form 3D networks of physically assembled nanofibres utilising non-covalent interactions. The nanofibrous structure of SAPs is often compared to that of electrospun scaffolds. These electrospun nanofibers are produced as sheets that can be engineered from a variety of polymers that can be chemically modified to incorporate many molecules including drugs and growth factors. However, their macroscale morphology limits them to wrapping and bandaging applications. Here, for the first time, we combine the benefits of these systems to describe a two-component composite scaffold from these biomaterials, with the design goal of providing a hydrogel scaffold that presents 3D structures, and also has temporal control over drug delivery. Short fibres, cut from electrospun scaffolds, were mixed with our tissue-specific SAP hydrogel to provide a range of nanofibre sizes found in the extracellular matrix (10-300 nm in diameter). The composite material maintained the shear-thinning and void-filling properties of SAP hydrogels that have previously been shown to be effective for minimally invasive material injection, cell delivery and subsequent in vivo integration. Both scaffold components were separately loaded with growth factors, important signaling molecules in tissue regeneration whose rapid degradation limits their clinical efficacy. The two biomaterials provided sequential growth factor delivery profiles: the SAP hydrogel provided a burst release, with the release rate decreasing over 12 hours, while the electrospun nanofibres provided a more constant, sustained delivery. Importantly, this second release commenced 6 days later. The design rules established here to provide temporally distinct release profiles can enable researchers to target specific stages in regeneration, such as the

  10. Emergency Entry with One Control Torque: Non-Axisymmetric Diagonal Inertia Matrix

    Science.gov (United States)

    Llama, Eduardo Garcia

    2011-01-01

    In another work, a method was presented, primarily conceived as an emergency backup system, that addressed the problem of a space capsule that needed to execute a safe atmospheric entry from an arbitrary initial attitude and angular rate in the absence of nominal control capability. The proposed concept permits the arrest of a tumbling motion, orientation to the heat shield forward position and the attainment of a ballistic roll rate of a rigid spacecraft with the use of control in one axis only. To show the feasibility of such concept, the technique of single input single output (SISO) feedback linearization using the Lie derivative method was employed and the problem was solved for different number of jets and for different configurations of the inertia matrix: the axisymmetric inertia matrix (I(sub xx) > I(sub yy) = I(sub zz)), a partially complete inertia matrix with I(sub xx) > I(sub yy) > I(sub zz), I(sub xz) not = 0 and a realistic complete inertia matrix with I(sub xx) > I(sub yy) > I)sub zz), I(sub ij) not= 0. The closed loop stability of the proposed non-linear control on the total angle of attack, Theta, was analyzed through the zero dynamics of the internal dynamics for the case where the inertia matrix is axisymmetric (I(sub xx) > I(sub yy) = I(sub zz)). This note focuses on the problem of the diagonal non-axisymmetric inertia matrix (I(sub xx) > I(sub yy) > I(sub zz)), which is half way between the axisymmetric and the partially complete inertia matrices. In this note, the control law for this type of inertia matrix will be determined and its closed-loop stability will be analyzed using the same methods that were used in the other work. In particular, it will be proven that the control system is stable in closed-loop when the actuators only provide a roll torque.

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

    African Journals Online (AJOL)

    Background: Malaria is a major public health problem in Sudan and causes an enormous burden of morbidity in the country. Malaria is generally controlled in Sudan using five main approaches, which are environmental management, space spraying (SS), insecticide-treated nets (ITNs), larviciding with abate (LWA) and ...

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. 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

  17. 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

  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. 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

  20. Linear Matrix Inequalities for Analysis and Control of Linear Vector Second-Order Systems

    DEFF Research Database (Denmark)

    Adegas, Fabiano Daher; Stoustrup, Jakob

    2015-01-01

    the Lyapunov matrix and the system matrices by introducing matrix multipliers, which potentially reduce conservativeness in hard control problems. Multipliers facilitate the usage of parameter-dependent Lyapunov functions as certificates of stability of uncertain and time-varying vector second-order systems......SUMMARY Many dynamical systems are modeled as vector second-order differential equations. This paper presents analysis and synthesis conditions in terms of LMI with explicit dependence in the coefficient matrices of vector second-order systems. These conditions benefit from the separation between....... The conditions introduced in this work have the potential to increase the practice of analyzing and controlling systems directly in vector second-order form. Copyright © 2014 John Wiley & Sons, Ltd....

  1. 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.

  2. 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…

  3. Factors associated with home delivery in Bahirdar, Ethiopia: a case control study.

    Science.gov (United States)

    Abebe, Fantu; Berhane, Yemane; Girma, Belaineh

    2012-11-24

    In Ethiopia although pregnant mothers increasingly attend antenatal clinics, utilization of skilled delivery service remains very low. The individual or health system factors that affect women's preferences for delivery places are not well known. A case control study was conducted in July 2010 to assess factors associated with utilization of institutional delivery service. A total of 324 mothers who recently delivered and visited either postnatal care or sought immunization services were included. Cases (n = 108) were mothers who gave birth at home and controls (n = 216) were those who delivered at health facility. Pre-tested and standardized questionnaires were used to collect relevant data by trained data collectors. Logistic regression model was used to control for confounding. The likelihood of delivering at home was greater among mothers with inadequate knowledge of pregnancy related services (AOR = 62, 95% CI: 3, 128.4), those who started attending ANC after 24 weeks of gestation (AOR 8.7, 95% CI: 2.2, 33.3), mothers having no formal education (Adjusted OR 4.2, 95% CI 1.63, 11.27) and rural residents (AOR = 3.6, 95%CI: 1.4, 9.0). The predominant factors associated with home delivery services were lack of knowledge about obstetrics care, delay in starting Antenatal Care (ANC) follow up, having, Illiteracy and rural residence. Audience specific behavioral change communication should be designed to improve the demand for delivery services. Health professionals should take the opportunity to encourage mothers attend delivery services during ANC follow up. Improvements should be made in social conditions including literacy and major social mobilization endeavors.

  4. Factors associated with home delivery in Bahirdar, Ethiopia: A case control study

    Directory of Open Access Journals (Sweden)

    Abebe Fantu

    2012-11-01

    Full Text Available Abstract Background In Ethiopia although pregnant mothers increasingly attend antenatal clinics, utilization of skilled delivery service remains very low. The individual or health system factors that affect women’s preferences for delivery places are not well known. Method A case control study was conducted in July 2010 to assess factors associated with utilization of institutional delivery service. A total of 324 mothers who recently delivered and visited either postnatal care or sought immunization services were included. Cases (n = 108 were mothers who gave birth at home and controls (n = 216 were those who delivered at health facility. Pre-tested and standardized questionnaires were used to collect relevant data by trained data collectors. Logistic regression model was used to control for confounding. Result The likelihood of delivering at home was greater among mothers with inadequate knowledge of pregnancy related services (AOR = 62, 95% CI: 3, 128.4, those who started attending ANC after 24 weeks of gestation (AOR 8.7, 95% CI: 2.2, 33.3, mothers having no formal education (Adjusted OR 4.2, 95% CI 1.63, 11.27 and rural residents (AOR = 3.6, 95%CI: 1.4, 9.0. Conclusion The predominant factors associated with home delivery services were lack of knowledge about obstetrics care, delay in starting Antenatal Care (ANC follow up, having, Illiteracy and rural residence. Audience specific behavioral change communication should be designed to improve the demand for delivery services. Health professionals should take the opportunity to encourage mothers attend delivery services during ANC follow up. Improvements should be made in social conditions including literacy and major social mobilization endeavors.

  5. 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

  6. Brown seaweed (Saccharina japonica) as an edible natural delivery matrix for allyl isothiocyanate inhibiting food-borne bacteria.

    Science.gov (United States)

    Siahaan, Evi Amelia; Pendleton, Phillip; Woo, Hee-Chul; Chun, Byung-Soo

    2014-01-01

    The edible, brown seaweed Saccharina japonica was prepared as powder in the size range 500-900 μm for the desorption release of allyl isothiocyanate (AITC). Powders were used as raw (containing lipids) and as de-oiled, where the lipid was removed. In general, de-oiled powders adsorbed larger masses of AITC after vapour or solution contact. Mass adsorbed due to solution contact exceeded vapour contact. Larger particles adsorbed more than smaller particles. No chemical bonding between AITC and the powder surface occurred. Release from vapour deposited particles reached 70-85% available within 72 h; solution deposited reached 70-90% available at 192 h. The larger amounts of AITC adsorbed via solution deposition resulted in greater vapour-phase concentrations at 72 h for antimicrobial activity studies. No loss of activity was detected against Escherichia coli, Salmonella Typhimurium or Bacillus cereus. Only a nominal activity against Staphylococcus aureus was demonstrated. S. japonica powder could be used as an edible, natural vehicle for AITC delivery. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Study of matrix converter as a current-controlled power supply in QUEST tokamak

    International Nuclear Information System (INIS)

    Liu, Xiaolong; Jiang, Yi; Nakamura, Kazuo

    2011-01-01

    Because QUEST tokamak has a divertor configuration with a higher κ and a negative n-index, a precise power supply with a rapid response is needed to control the vertical position of the plasma. A matrix converter is a direct power conversion device that uses an array of controlled bidirectional switches as the main power elements for creating a variable-output current system. This paper presents a novel three-phase to two-phase topological matrix converter as a proposed power supply that stabilizes the plasma vertical position and achieves unity input power factor. An indirect control strategy in which the matrix converter is split into a virtual rectifier stage and a virtual inverter stage is adopted. In the virtual rectifier stage, the instantaneous active power and reactive power are decoupled on the basis of system equations derived from the DQ transformation; hence, unity power factor is achieved. Space vector pulse width modulation is adopted to determine the switching time of each switch in the virtual rectifier; the output voltage of the virtual rectifier is adjusted by the virtual inverter stage to obtain the desired load current. Theoretical analyses and simulation results are provided to verify its feasibility. (author)

  8. 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.

  9. 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

  10. 3D Printed Microtransporters: Compound Micromachines for Spatiotemporally Controlled Delivery of Therapeutic Agents.

    Science.gov (United States)

    Huang, Tian-Yun; Sakar, Mahmut Selman; Mao, Angelo; Petruska, Andrew J; Qiu, Famin; Chen, Xue-Bo; Kennedy, Stephen; Mooney, David; Nelson, Bradley J

    2015-11-01

    Functional compound micromachines are fabricated by a design methodology using 3D direct laser writing and selective physical vapor deposition of magnetic materials. Microtransporters with a wirelessly controlled Archimedes screw pumping mechanism are engineered. Spatiotemporally controlled collection, transport, and delivery of micro particles, as well as magnetic nanohelices inside microfluidic channels are demonstrated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Nanoparticle enabled transdermal drug delivery systems for enhanced dose control and tissue targeting

    Science.gov (United States)

    Palmer, Brian C.; DeLouise, Lisa A.

    2017-01-01

    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. PMID:27983701

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

    Science.gov (United States)

    Palmer, Brian C; DeLouise, Lisa A

    2016-12-15

    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.

  13. 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.

  14. 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.

  15. Design of distributed PID-type dynamic matrix controller for fractional-order systems

    Science.gov (United States)

    Wang, Dawei; Zhang, Ridong

    2018-01-01

    With the continuous requirements for product quality and safety operation in industrial production, it is difficult to describe the complex large-scale processes with integer-order differential equations. However, the fractional differential equations may precisely represent the intrinsic characteristics of such systems. In this paper, a distributed PID-type dynamic matrix control method based on fractional-order systems is proposed. First, the high-order approximate model of integer order is obtained by utilising the Oustaloup method. Then, the step response model vectors of the plant is obtained on the basis of the high-order model, and the online optimisation for multivariable processes is transformed into the optimisation of each small-scale subsystem that is regarded as a sub-plant controlled in the distributed framework. Furthermore, the PID operator is introduced into the performance index of each subsystem and the fractional-order PID-type dynamic matrix controller is designed based on Nash optimisation strategy. The information exchange among the subsystems is realised through the distributed control structure so as to complete the optimisation task of the whole large-scale system. Finally, the control performance of the designed controller in this paper is verified by an example.

  16. Biosensor-controlled gene therapy/drug delivery with nanoparticles for nanomedicine

    Science.gov (United States)

    Prow, Tarl W.; Rose, William A.; Wang, Nan; Reece, Lisa M.; Lvov, Yuri; Leary, James F.

    2005-04-01

    Nanomedicine involves cell-by-cell regenerative medicine, either repairing cells one at a time or triggering apoptotic pathways in cells that are not repairable. Multilayered nanoparticle systems are being constructed for the targeted delivery of gene therapy to single cells. Cleavable shells containing targeting, biosensing, and gene therapeutic molecules are being constructed to direct nanoparticles to desired intracellular targets. Therapeutic gene sequences are controlled by biosensor-activated control switches to provide the proper amount of gene therapy on a single cell basis. The central idea is to set up gene therapy "nanofactories" inside single living cells. Molecular biosensors linked to these genes control their expression. Gene delivery is started in response to a biosensor detected problem; gene delivery is halted when the cell response indicates that more gene therapy is not needed. Cell targeting of nanoparticles, both nanocrystals and nanocapsules, has been tested by a combination of fluorescent tracking dyes, fluorescence microscopy and flow cytometry. Intracellular targeting has been tested by confocal microscopy. Successful gene delivery has been visualized by use of GFP reporter sequences. DNA tethering techniques were used to increase the level of expression of these genes. Integrated nanomedical systems are being designed, constructed, and tested in-vitro, ex-vivo, and in small animals. While still in its infancy, nanomedicine represents a paradigm shift in thinking-from destruction of injured cells by surgery, radiation, chemotherapy to cell-by-cell repair within an organ and destruction of non-repairable cells by natural apoptosis.

  17. 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

  18. Drug release control and system understanding of sucrose esters matrix tablets by artificial neural networks.

    Science.gov (United States)

    Chansanroj, Krisanin; Petrović, Jelena; Ibrić, Svetlana; Betz, Gabriele

    2011-10-09

    Artificial neural networks (ANNs) were applied for system understanding and prediction of drug release properties from direct compacted matrix tablets using sucrose esters (SEs) as matrix-forming agents for controlled release of a highly water soluble drug, metoprolol tartrate. Complexity of the system was presented through the effects of SE concentration and tablet porosity at various hydrophilic-lipophilic balance (HLB) values of SEs ranging from 0 to 16. Both effects contributed to release behaviors especially in the system containing hydrophilic SEs where swelling phenomena occurred. A self-organizing map neural network (SOM) was applied for visualizing interrelation among the variables and multilayer perceptron neural networks (MLPs) were employed to generalize the system and predict the drug release properties based on HLB value and concentration of SEs and tablet properties, i.e., tablet porosity, volume and tensile strength. Accurate prediction was obtained after systematically optimizing network performance based on learning algorithm of MLP. Drug release was mainly attributed to the effects of SEs, tablet volume and tensile strength in multi-dimensional interrelation whereas tablet porosity gave a small impact. Ability of system generalization and accurate prediction of the drug release properties proves the validity of SOM and MLPs for the formulation modeling of direct compacted matrix tablets containing controlled release agents of different material properties. Copyright © 2011 Elsevier B.V. All rights reserved.

  19. 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.

  20. Building a polysaccharide hydrogel capsule delivery system for control release of ibuprofen.

    Science.gov (United States)

    Chen, Zhi; Wang, Ting; Yan, Qing

    2018-02-01

    Development of a delivery system which can effectively carry hydrophobic drugs and have pH response is becoming necessary. Here we demonstrate that through preparation of β-cyclodextrin polymer (β-CDP), a hydrophobic drug molecule of ibuprofen (IBU) was incorporated into our prepared β-CDP inner cavities, aiming to improve the poor water solubility of IBU. A core-shell capsule structure has been designed for achieving the drug pH targeted and sustained release. This delivery system was built with polysaccharide polymer of Sodium alginate (SA), sodium carboxymethylcellulose (CMC) and hydroxyethyl cellulose (HEC) by physical cross-linking. The drug pH-response control release is this hydrogel system's chief merit, which has potential value for synthesizing enteric capsule. Besides, due to our simple preparing strategy, optimal conditions can be readily determined and the synthesis process can be accurately controlled, leading to consistent and reproducible hydrogel capsules. In addition, phase-solubility method was used to investigate the solubilization effect of IBU by β-CDP. SEM was used to prove the forming of core and shell structure. FT-IR and 1 H-NMR were also used to perform structural characteristics. By the technique of UV determination, the pH targeted and sustained release study were also performed. The results have proved that our prepared polysaccharide hydrogel capsule delivery system has potential applications as oral drugs delivery in the field of biomedical materials.

  1. Wireless implantable chip with integrated nitinol-based pump for radio-controlled local drug delivery.

    Science.gov (United States)

    Fong, Jeffrey; Xiao, Zhiming; Takahata, Kenichi

    2015-02-21

    We demonstrate an active, implantable drug delivery device embedded with a microfluidic pump that is driven by a radio-controlled actuator for temporal drug delivery. The polyimide-packaged 10 × 10 × 2 mm(3) chip contains a micromachined pump chamber and check valves of Parylene C to force the release of the drug from a 76 μL reservoir by wirelessly activating the actuator using external radio-frequency (RF) electromagnetic fields. The rectangular-shaped spiral-coil actuator based on nitinol, a biocompatible shape-memory alloy, is developed to perform cantilever-like actuation for pumping operation. The nitinol-coil actuator itself forms a passive 185 MHz resonant circuit that serves as a self-heat source activated via RF power transfer to enable frequency-selective actuation and pumping. Experimental wireless operation of fabricated prototypes shows successful release of test agents from the devices placed in liquid and excited by radiating tuned RF fields with an output power of 1.1 W. These tests reveal a single release volume of 219 nL, suggesting a device's capacity of ~350 individual ejections of drug from its reservoir. The thermal behavior of the activated device is also reported in detail. This proof-of-concept prototype validates the effectiveness of wireless RF pumping for fully controlled, long-lasting drug delivery, a key step towards enabling patient-tailored, targeted local drug delivery through highly miniaturized implants.

  2. 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.

  3. 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

  4. 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.

  5. 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)

  6. 3-D conformal radiation therapy - Part II: Computer-controlled 3-D treatment delivery

    International Nuclear Information System (INIS)

    Benedick, A.

    1997-01-01

    Purpose/Objective: This course will describe the use of computer-controlled treatment delivery techniques for treatment of patients with sophisticated conformal therapy. In particular, research and implementation issues related to clinical use of computer-controlled conformal radiation therapy (CCRT) techniques will be discussed. The possible/potential advantages of CCRT techniques will be highlighted using results from clinical 3-D planning studies. Materials and Methods: In recent years, 3-D treatment planning has been used to develop and implement 3-D conformal therapy treatment techniques, and studies based on these conformal treatments have begun to show the promise of conformal therapy. This work has been followed by the development of commercially-available multileaf collimator and computer control systems for treatment machines. Using these (and other) CCRT devices, various centers are beginning to clinically use complex computer-controlled treatments. Both research and clinical CCRT treatment techniques will be discussed in this presentation. General concepts and requirements for CCRT will be mentioned. Developmental and clinical experience with CCRT techniques from a number of centers will be utilized. Results: Treatment planning, treatment preparation and treatment delivery must be approached in an integrated fashion in order to clinically implement CCRT treatment techniques, and the entire process will be discussed. Various CCRT treatment methodologies will be reviewed from operational, dosimetric, and technical points of view. The discussion will concentrate on CCRT techniques which are likely to see rather wide dissemination over the next several years, including particularly the use of multileaf collimators (MLC), dynamic and segmental conformal therapy, conformal field shaping, and other related techniques. More advanced CCRT techniques, such as the use of individualized intensity modulation of beams or segments, and the use of computer-controlled

  7. Control, communication and monitoring of intravaginal drug delivery in dairy cows.

    Science.gov (United States)

    Cross, Peter S; Künnemeyer, Rainer; Bunt, Craig R; Carnegie, Dale A; Rathbone, Michael J

    2004-09-10

    We present the design of an electronically controlled drug delivery system. The intravaginally located device is a low-invasive platform that can measure and react inside the cow vagina while providing external control and monitoring ability. The electronics manufactured from off the shelf components occupies 16 mL of a Theratron syringe. A microcontroller reads and logs sensor data and controls a gascell. The generated gas pressure propels the syringe piston and releases the formulation. A two way radio link allows communication between other devices or a base station. Proof of principle experiments confirm variable-rate, arbitrary profile drug delivery qualified by internal sensors. A total volume of 30 mL was dispensed over a 7-day-period with a volume error of +/- 1 mL or +/- 7% for larger volumes. Delivery was controlled or overridden via the wireless link, and proximity to other devices was detected and recorded. The results suggest that temperature and activity sensing or social grouping determined via proximity can be used to detect oestrus and trigger appropriate responses.

  8. 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.)

  9. 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.

  10. Control system and method for a power delivery system having a continuously variable ratio transmission

    Science.gov (United States)

    Frank, Andrew A.

    1984-01-01

    A control system and method for a power delivery system, such as in an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Totally independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for minimum fuel consumption. CVT ratio is controlled as a function of commanded power or torque and measured load, while engine fuel requirements (e.g., throttle position) are strictly a function of measured engine speed. Fuel requirements are therefore precisely adjusted in accordance with the ideal characteristic for any load placed on the engine.

  11. 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...

  12. 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.

  13. 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.

  14. 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)

  15. Robust Model Predictive Control Using Linear Matrix Inequalities for the Treatment of Asymmetric Output Constraints

    Directory of Open Access Journals (Sweden)

    Mariana Santos Matos Cavalca

    2012-01-01

    Full Text Available One of the main advantages of predictive control approaches is the capability of dealing explicitly with constraints on the manipulated and output variables. However, if the predictive control formulation does not consider model uncertainties, then the constraint satisfaction may be compromised. A solution for this inconvenience is to use robust model predictive control (RMPC strategies based on linear matrix inequalities (LMIs. However, LMI-based RMPC formulations typically consider only symmetric constraints. This paper proposes a method based on pseudoreferences to treat asymmetric output constraints in integrating SISO systems. Such technique guarantees robust constraint satisfaction and convergence of the state to the desired equilibrium point. A case study using numerical simulation indicates that satisfactory results can be achieved.

  16. Current phase control test based on real-time measurement of impedance matrix of ICRF antennas

    Energy Technology Data Exchange (ETDEWEB)

    Saito, K., E-mail: saito@nifs.ac.jp [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan); Kumazawa, R.; Seki, T.; Kasahara, H.; Yokota, M.; Nomura, G.; Shimpo, F.; Mutoh, T. [National Institute for Fusion Science, Toki, Gifu 509-5292 (Japan)

    2011-10-15

    New ion cyclotron range of frequencies (ICRF) antennas have just been installed in the large helical device (LHD). These side-by-side ICRF antennas are symmetrical and designed to launch fast waves with various wave numbers parallel to the magnetic field line. The wave number can be controlled by changing the current phase on the straps; however, the mutual coupling between antennas changes antenna impedances, even if the plasma parameters are constant, leading to an increase in the reflected power. In addition to the current phase control, impedance matching devices must be tuned for the protection of tetrode tubes and efficient power injection. For this purpose, the impedance matrix of ICRF antennas must be determined, and it can be deduced from the forward and reflected waves at the outlet of the power amplifier by assuming geometric symmetry and reciprocity of the antennas. Using half-scale antennas, we successfully demonstrated simultaneous impedance matching and current phase control.

  17. Minimal representation of matrix valued white stochastic processes and U–D factorisation of algorithms for optimal control

    NARCIS (Netherlands)

    Willigenburg, van L.G.; Koning, de W.L.

    2013-01-01

    Two different descriptions are used in the literature to formulate the optimal dynamic output feedback control problem for linear dynamical systems with white stochastic parameters and quadratic criteria, called the optimal compensation problem. One describes the matrix valued white stochastic

  18. Temperature and pH Responsive Microfibers for Controllable and Variable Ibuprofen Delivery

    Directory of Open Access Journals (Sweden)

    Toan Tran

    2015-01-01

    Full Text Available Electrospun microfibers (MFs composed of pH and temperature responsive polymers can be used for controllable and variable delivery of ibuprofen. First, electrospinning technique was employed to prepare poly(ε-caprolactone (PCL and poly(N-isopropylacrylamide-co-methacrylic acid (pNIPAM-co-MAA MFs containing ibuprofen. It was found that drug release rates from PCL MFs cannot be significantly varied by either temperature (22–40°C or pH values (1.7–7.4. In contrast, the ibuprofen (IP diffusion rates from pNIPAM-co-MAA MFs were very sensitive to changes in both temperature and pH. The IP release from pNIPAM-co-MAA MFs was highly linear and controllable when the temperature was above the lower critical solution temperature (LCST of pNIPAM-co-MAA (33°C and the pH was lower than the pKa of carboxylic acids (pH 2. At room temperature, however, the release rate was dramatically increased by nearly ten times compared to that at higher temperature and lower pH. Such a unique and controllable drug delivery system could be naturally envisioned to find many practical applications in biomedical and pharmaceutical sciences such as programmable transdermal drug delivery.

  19. 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.

  20. 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.

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

    International Nuclear Information System (INIS)

    Pathania, Deepak; Gupta, Divya; Agarwal, Shilpi; Asif, M.; Gupta, Vinod Kumar

    2016-01-01

    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.

  2. 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.

  3. Multifunctional halloysite nanotubes for targeted delivery and controlled release of doxorubicin in-vitro and in-vivo studies

    Science.gov (United States)

    Hu, Yuwei; Chen, Jian; Li, Xiufang; Sun, Yanhua; Huang, Shen; Li, Yuqing; Liu, Hui; Xu, Jiangfeng; Zhong, Shian

    2017-09-01

    The current state of cancer therapy encourages researchers to develop novel efficient nanocarriers. Halloysite nanotubes (HNTs) are good nanocarrier candidates due to their unique nanoscale (40-80 nm in diamter and 200-500 nm in length) and hollow lumen, as well as good biocompatibility and low cost. In our study, we prepared a type of folate-mediated targeting and redox-triggered anticancer drug delivery system, so that Doxorubicin (DOX) can be specifically transported to tumor sites due to the over-expressed folate-receptors on the surface of cancer cells. Furthermore, it can then be released by the reductive agent glutathione (GSH) in cancer cells where the content of GSH is nearly 103-fold higher than in the extracellular matrix. A series of methods have demonstrated that per-thiol-β-cyclodextrin (β-CD-(SH)7) was successfully combined with HNTs via a redox-responsive disulfide bond, and folic acid-polyethylene glycol-adamantane (FA-PEG-Ad) was immobilized on the HNTs through the strong complexation between β-CD/Ad. In vitro studies indicated that the release rate of DOX raised sharply in dithiothreitol (DTT) reducing environment and the amount of released DOX reached 70% in 10 mM DTT within the first 10 h, while only 40% of DOX was released in phosphate buffer solution (PBS) even after 79 h. Furthermore, the targeted HNTs could be specifically endocytosed by over-expressed folate-receptor cancer cells and significantly accelerate the apoptosis of cancer cells compared to non-targeted HNTs. In vivo studies further verified that the targeted HNTs had the best therapeutic efficacy and no obvious side effects for tumor-bearing nude mice, while free DOX showed damaging effects on normal tissues. In summary, this novel nanocarrier system shows excellent potential for targeted delivery and controlled release of anticancer drugs and provides a potential platform for tumor therapy.

  4. Patient-controlled analgesia : therapeutic interventions using transdermal electro-activated and electro-modulated drug delivery

    NARCIS (Netherlands)

    Indermun, S.; Choonara, Y.E.; Kumar, P.; Du Toit, L.C.; Modi, G.; Luttge, R.; Pillay, V.

    2014-01-01

    Chronic pain poses a major concern to modern medicine and is frequently undertreated, causing suffering and disability. Patient-controlled analgesia, although successful, does have limitations. Transdermal delivery is the pivot to which analgesic research in drug delivery has centralized, especially

  5. Vaccine delivery to disease control: a paradigm shift in health policy.

    Science.gov (United States)

    John, T Jacob; Jain, Yogesh; Nadimpally, Sarojini; Jesani, Amar

    2017-01-01

    India's Universal Immunisation Programme (UIP) has resulted in the creation of infrastructure, human resources and systems for the procurement and delivery of vaccines. Recently, new vaccines have been added and there are plans for the introduction of more. However, the outcomes in terms of reduction of the diseases for which the vaccines are being administered remain ambiguous. This is evident from the persistent health issues that children continue to experience, despite immunisation. This situation raises a fundamental ethical question for public health: vaccinations are one of the tools of disease control, but are they properly aligned to the control of disease so as to produce the expected public health utility or benefit?

  6. 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.

  7. Needle-free delivery of macromolecules through the skin using controllable jet injectors.

    Science.gov (United States)

    Hogan, Nora C; Taberner, Andrew J; Jones, Lynette A; Hunter, Ian W

    2015-01-01

    Transdermal delivery of drugs has a number of advantages in comparison to other routes of administration. The mechanical properties of skin, however, impose a barrier to administration and so most compounds are administered using hypodermic needles and syringes. In order to overcome some of the issues associated with the use of needles, a variety of non-needle devices based on jet injection technology has been developed. Jet injection has been used primarily for vaccine administration but has also been used to deliver macromolecules such as hormones, monoclonal antibodies and nucleic acids. A critical component in the more recent success of jet injection technology has been the active control of pressure applied to the drug during the time course of injection. Jet injection systems that are electronically controllable and reversible offer significant advantages over conventional injection systems. These devices can consistently create the high pressures and jet speeds necessary to penetrate tissue and then transition smoothly to a lower jet speed for delivery of the remainder of the desired dose. It seems likely that in the future this work will result in smart drug delivery systems incorporated into personal medical devices and medical robots for in-home disease management and healthcare.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

    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.

  9. 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.

  10. 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.

  11. DOE Optimization of Nano-based Carrier of Pregabalin as Hydrogel: New Therapeutic & Chemometric Approaches for Controlled Drug Delivery Systems

    Science.gov (United States)

    Arafa, Mona G.; Ayoub, Bassam M.

    2017-01-01

    Niosomes entrapping pregabalin (PG) were prepared using span 60 and cholesterol in different molar ratios by hydration method, the remaining PG from the hydrating solution was separated from vesicles by freeze centrifugation. Optimization of nano-based carrier of pregabalin (PG) was achieved. Quality by Design strategy was successfully employed to obtain PG-loaded niosomes with the desired properties. The optimal particle size, drug release and entrapment efficiency were attained by Minitab® program using design of experiment (DOE) that predicted the best parameters by investigating the combined effect of different factors simultaneously. Pareto chart was used in the screening step to exclude the insignificant variables while response surface methodology (RSM) was used in the optimization step to study the significant factors. Best formula was selected to prepare topical hydrogels loaded with niosomal PG using HPMC and Carbopol 934. It was verified, by means of mechanical and rheological tests, that addition of the vesicles to the gel matrix affected significantly gel network. In vitro release and ex vivo permeation experiments were carried out. Delivery of PG molecules followed a Higuchi, non Fickian diffusion. The present work will be of interest for pharmaceutical industry as a controlled transdermal alternative to the conventional oral route.

  12. 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

  13. Novel Polysaccharide Based Polymers and Nanoparticles for Controlled Drug Delivery and Biomedical Imaging

    Science.gov (United States)

    Shalviri, Alireza

    controlled delivery applications of larger molecular size compounds. The starch based hydrogels, polymers and nanoparticles developed in this work have shown great potentials for controlled drug delivery and biomedical imaging applications.

  14. Controlled-release, pegylation, liposomal formulations: new mechanisms in the delivery of injectable drugs.

    Science.gov (United States)

    Reddy, K R

    2000-01-01

    To review recent developments in novel injectable drug delivery mechanisms and outline the advantages and disadvantages of each. A MEDLINE (1995-January 2000) search using the terms polyethylene glycol, liposomes, polymers, polylactic acid, and controlled release was conducted. Additional references were identified by scanning bibliographies. All articles were considered for inclusion. Abstracts were included only if they were judged to add critical information not otherwise available in the medical literature. A number of systems that alter the delivery of injectable drugs have been developed in attempts to improve pharmacodynamic and pharmacokinetic properties of therapeutic agents. New drug delivery systems can be produced either through a change in formulation (e.g., continuous-release products, liposomes) or an addition to the drug molecule (e.g., pegylation). Potential advantages of new delivery mechanisms include an increased or prolonged duration of pharmacologic activity, a decrease in adverse effects, and increased patient compliance and quality of life. Injectable continuous-release systems deliver drugs in a controlled, predetermined fashion and are particularly appropriate when it is important to avoid large fluctuations in plasma drug concentrations. Encapsulating a drug within a liposome can produce a prolonged half-life and a shift of distribution toward tissues with increased capillary permeability (e.g., tumors, infected tissue). Pegylation provides a method for modification of therapeutic proteins to minimize many of the limitations (e.g., poor stability, short half-life, immunogenicity) associated with these agents. Pegylation of therapeutic proteins is an established process with new applications. However, not all pegylated proteins are alike, and each requires optimization on a protein-by-protein basis to derive maximum clinical benefit. The language required to describe each pegylated therapeutic protein must be more precise to accurately

  15. 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.

  16. Analysis and control of induction generator supplying stand-alone AC loads employing a Matrix Converter

    Directory of Open Access Journals (Sweden)

    Sumedha Mahajan

    2017-04-01

    Full Text Available This paper proposes a Capacitor Excited Induction Generator (CEIG-Matrix Converter (MC system for feeding stand-alone AC loads. The variable output voltage magnitude and frequency from CEIG is converted into a constant voltage magnitude and frequency at the load terminals by controlling MC using Space Vector Modulation (SVM technique. This single-stage MC is turned up as a good alternative for the proposed system against commonly used AC/DC/AC two stage power converters. The configuration and implementation of the closed-loop control scheme employing dSPACE 1103 real time controller have been fully described in the paper. The proposed closed-loop controller regulates the AC load voltage irrespective of changes in the prime mover speed and load. A method for predetermining the steady-state performance of the proposed system has been developed and described with relevant analytical expressions. The effectiveness of the proposed system is exemplified through simulation results for various operating conditions. The proposed control technique is further validated using an experimental setup developed in the laboratory.

  17. 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......-based modulation method, indirect space vector modulation and optimum Alesina-Venturini, the FCS-MPC has known and unchanged switching state in a sampling period. It is simpler to diagnose the exact location of the open switch in MC with FCS-MPC. To achieve better quality of the output current under single open...

  18. 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.

  19. 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.

  20. Inner layer-embedded contact lenses for pH-triggered controlled ocular drug delivery.

    Science.gov (United States)

    Zhu, Qiang; Liu, Chang; Sun, Zheng; Zhang, Xiaofei; Liang, Ning; Mao, Shirui

    2018-07-01

    Contact lenses (CLs) are ideally suited for controlled ocular drug delivery, but are limited by short release duration, poor storage stability and low drug loading. In this study, we present a novel inner layer-embedded contact lens capable of pH-triggered extended ocular drug delivery with good storage stability. Blend film of ethyl cellulose and Eudragit S100 was used as the inner layer, while pHEMA hydrogel was used as outer layer to fabricate inner layer-embedded contact lens. Using diclofenac sodium(DS) as a drug model, influence of polymer ratio in the blend film, EC viscosity, drug/polymer ratio, inner layer thickness and outlayer thickness of pHEMA hydrogel on drug release behavior was studied and optimized for daily use. The pH-triggered drug eluting pattern enables the inner layer-embedded contact lens being stored in phosphate buffer solution pH 6.8 with ignorable drug loss and negligible changes in drug release pattern. In vivo pharmacokinetic study in rabbits showed sustained drug release for over 24 h in tear fluid, indicating significant improvement in drug corneal residence time. A level A IVIVC was established between in vitro drug release and in vivo drug concentration in tear fluid. In conclusion, this inner layer embedded contact lens design could be used as a platform for extended ocular drug delivery with translational potential for both anterior and posterior ocular diseases therapy. Copyright © 2018 Elsevier B.V. All rights reserved.

  1. [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.

  2. 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...... and unbalanced directed graphs. Average consensus is guaranteed in unbalanced digraphs by updating the weight matrix with both its row sums and column sums being 1. Simulation examples illustrate the effectiveness of the proposed control method....

  3. Transversus Abdominis Plane Block Versus Wound Infiltration for Analgesia After Cesarean Delivery: A Randomized Controlled Trial.

    Science.gov (United States)

    Tawfik, Mohamed Mohamed; Mohamed, Yaser Mohamed; Elbadrawi, Rania Elmohamadi; Abdelkhalek, Mostafa; Mogahed, Maiseloon Mostafa; Ezz, Hanaa Mohamed

    2017-04-01

    Transversus abdominis plane (TAP) block and local anesthetic wound infiltration provide analgesia after cesarean delivery. Studies comparing the 2 techniques are scarce, with conflicting results. This double-blind, randomized controlled trial aimed to compare bilateral ultrasound-guided TAP block with single-shot local anesthetic wound infiltration for analgesia after cesarean delivery performed under spinal anesthesia. We hypothesized that the TAP block would decrease postoperative cumulative fentanyl consumption at 24 hours. Eligible subjects were American Society of Anesthesiologists physical status II parturients with full-term singleton pregnancies undergoing elective cesarean delivery under spinal anesthesia. Exclusion criteria were: 40 years of age; height consumption at 24 hours. Secondary outcomes were the time to the first postoperative fentanyl dose, cumulative fentanyl consumption at 2, 4, 6, and 12 hours, pain scores at rest and on movement at 2, 4, 6, 12, and 24 hours, the deepest level of sedation, the incidence of side effects (nausea and vomiting and pruritis), and patient satisfaction. Data from 78 patients (39 patients in each group) were analyzed. The mean ± SD of cumulative fentanyl consumption at 24 hours was 157.4 ± 63.4 μg in the infiltration group and 153.3 ± 68.3 μg in the TAP group (difference in means [95% confidence interval] is 4.1 [-25.6 to 33.8] μg; P = .8). There were no significant differences between the 2 groups in the time to the first postoperative fentanyl dose, cumulative fentanyl consumption at 2, 4, 6, and 12 hours, pain scores at rest and on movement at 2, 4, 6, 12, and 24 hours, the deepest level of sedation, and patient satisfaction. The incidence of side effects (nausea and vomiting and pruritis) was low in the 2 groups. TAP block and wound infiltration did not significantly differ regarding postoperative fentanyl consumption, pain scores, and patient satisfaction in parturients undergoing cesarean delivery under

  4. 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

  5. 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 engineering.

  6. 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.

  7. 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 (pcontrol limits, that is, been out of statistical control. The proportion of cases that were managed consistently with the guidelines increased for all of their main components. Implementation of continuous 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.

  8. Biodistribution of doxorubicin and nanostructured ferrocarbon carrier particles in organism during magnetically controlled drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Kuznetsov, Anatoly A.; Filippov, Victor I.; Nikolskaya, Tatiana A. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation); Budko, Andrei P. [Oncological Center, Russian Academy of Medical Sciences, Moscow (Russian Federation); Kovarskii, Alexander L. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation); Zontov, Sergei V. [Oncological Center, Russian Academy of Medical Sciences, Moscow (Russian Federation); Kogan, Boris Ya. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation); Kuznetsov, Oleg A. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation)], E-mail: kuznetsov_oa@yahoo.com

    2009-05-15

    Biodistribution of doxorubicin and ferrocarbon carrier particles in organism during and after magnetically controlled anti-tumor drug delivery and deposition was studied. Animal tests show high concentration of the cytostatic drug in the target zone, while its concentration is three orders of magnitude lower in bloodstream and other organs. A significant depot of the drug remains on the deposited particles days after the procedure. Macrophages actively phagocytose the ferrocarbon (FeC) particles and remain viable long enough to carry them to the lymph nodes.

  9. Biodistribution of doxorubicin and nanostructured ferrocarbon carrier particles in organism during magnetically controlled drug delivery

    International Nuclear Information System (INIS)

    Kuznetsov, Anatoly A.; Filippov, Victor I.; Nikolskaya, Tatiana A.; Budko, Andrei P.; Kovarskii, Alexander L.; Zontov, Sergei V.; Kogan, Boris Ya.; Kuznetsov, Oleg A.

    2009-01-01

    Biodistribution of doxorubicin and ferrocarbon carrier particles in organism during and after magnetically controlled anti-tumor drug delivery and deposition was studied. Animal tests show high concentration of the cytostatic drug in the target zone, while its concentration is three orders of magnitude lower in bloodstream and other organs. A significant depot of the drug remains on the deposited particles days after the procedure. Macrophages actively phagocytose the ferrocarbon (FeC) particles and remain viable long enough to carry them to the lymph nodes.

  10. Controlled release hydrophilic matrix tablet formulations of isoniazid: design and in vitro studies.

    Science.gov (United States)

    Hiremath, Praveen S; Saha, Ranendra N

    2008-01-01

    The aim of the present investigation was to develop oral controlled release matrix tablet formulations of isoniazid using hydroxypropyl methylcellulose (HPMC) as a hydrophilic release retardant polymer and to study the influence of various formulation factors like proportion of the polymer, polymer viscosity grade, compression force, and release media on the in vitro release characteristics of the drug. The formulations were developed using wet granulation technology. The in vitro release studies were performed using US Pharmacopoeia type 1 apparatus (basket method) in 900 ml of pH 7.4 phosphate buffer at 100 rpm. The release kinetics was analyzed using Korsmeyer-Peppas model. The release profiles were also analyzed using statistical method (one-way analysis of variance) and f (2) metric values. The release profiles found to follow Higuchi's square root kinetics model irrespective of the polymer ratio and the viscosity grade used. The results in the present investigation confirm that the release rate of the drug from the HPMC matrices is highly influenced by the drug/HPMC ratio and viscosity grade of the HPMC. Also, the effect of compression force and release media was found to be significant on the release profiles of isoniazid from HPMC matrix tablets. The release mechanism was found to be anomalous non-Fickian diffusion in all the cases. In the present investigation, a series of controlled release formulations of isoniazid were developed with different release rates and duration so that these formulations could further be assessed from the in vivo bioavailability studies. The formulations were found to be stable and reproducible.

  11. 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.

  12. 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.

  13. In vivo real-time monitoring system of electroporation mediated control of transdermal and topical drug delivery.

    Science.gov (United States)

    Blagus, Tanja; Markelc, Bostjan; Cemazar, Maja; Kosjek, Tina; Preat, Veronique; Miklavcic, Damijan; Sersa, Gregor

    2013-12-28

    Electroporation (EP) is a physical method for the delivery of molecules into cells and tissues, including the skin. In this study, in order to control the degree of transdermal and topical drug delivery, EP at different amplitudes of electric pulses was evaluated. A new in vivo real-time monitoring system based on fluorescently labeled molecules was developed, for the quantification of transdermal and topical drug delivery. EP of the mouse skin was performed with new non-invasive multi-array electrodes, delivering different amplitudes of electric pulses ranging from 70 to 570 V, between the electrode pin pairs. Patches, soaked with 4 kDa fluorescein-isothiocyanate labeled dextran (FD), doxorubicin (DOX) or fentanyl (FEN), were applied to the skin before and after EP. The new monitoring system was developed based on the delivery of FD to and through the skin. FD relative quantity was determined with fluorescence microscopy imaging, in the treated region of the skin for topical delivery and in a segment of the mouse tail for transdermal delivery. The application of electric pulses for FD delivery resulted in enhanced transdermal delivery. Depending on the amplitude of electric pulses, it increased up to the amplitude of 360 V, and decreased at higher amplitudes (460 and 570 V). Topical delivery steadily enhanced with increasing the amplitude of the delivered electric pulses, being even higher than after tape stripping used as a positive control. The non-invasive monitoring of the delivery of DOX, a fluorescent chemotherapeutic drug, qualitatively and quantitatively confirmed the effects of EP at 360 and 570 V pulse amplitudes on topical and transdermal drug delivery. Delivery of FEN at 360 and 570 V pulse amplitudes verified the observed effects as obtained with FD and DOX, by the measured physiological responses of the mice as well as FEN plasma concentration. This study demonstrates that with the newly developed non-invasive multi-array electrodes and with the

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Modulation of electrostatic interactions to improve controlled drug delivery from nanogels

    Energy Technology Data Exchange (ETDEWEB)

    Mauri, Emanuele; Chincarini, Giulia M.F.; Rigamonti, Riccardo; Magagnin, Luca; Sacchetti, Alessandro, E-mail: alessandro.sacchetti@polimi.it; Rossi, Filippo, E-mail: filippo.rossi@polimi.it

    2017-03-01

    The synthesis of nanogels as devices capable to maintain the drug level within a desired range for a long and sustained period of time is a leading strategy in controlled drug delivery. However, with respect to the good results obtained with antibodies and peptides there are a lot of problems related to the quick and uncontrolled diffusion of small hydrophilic molecules through polymeric network pores. For these reasons research community is pointing toward the use of click strategies to reduce release rates of the linked drugs to the polymer chains. Here we propose an alternative method that considers the electrostatic interactions between polymeric chains and drugs to tune the release kinetics from nanogel network. The main advantage of these systems lies in the fact that the carried drugs are not modified and no chemical reactions take place during their loading and release. In this work we synthesized PEG-PEI based nanogels with different protonation degrees and the release kinetics with charged and uncharged drug mimetics (sodium fluorescein, SF, and rhodamine B, RhB) were studied. Moreover, also the effect of counterion used to induce protonation was taken into account in order to build a tunable drug delivery system able to provide multiple release rates with the same device. - Highlights: • The design of nanogels as drug delivery systems based on electrostatic interaction among drug and polymers is proposed. • Nanogels can be synthetized tuning their positive charge density, according to the protonation of PEI at different pH. • No biorthogonal chemistry strategies are applied to the polymers or drugs. • Drug release is efficiently modulated by charge density of PEI chains. • The effect of counterion on nanogel synthesis is investigated and allows controlling the drug release.

  19. 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

  20. Patient-controlled analgesia: therapeutic interventions using transdermal electro-activated and electro-modulated drug delivery.

    Science.gov (United States)

    Indermun, Sunaina; Choonara, Yahya E; Kumar, Pradeep; Du Toit, Lisa C; Modi, Girish; Luttge, Regina; Pillay, Viness

    2014-02-01

    Chronic pain poses a major concern to modern medicine and is frequently undertreated, causing suffering and disability. Patient-controlled analgesia, although successful, does have limitations. Transdermal delivery is the pivot to which analgesic research in drug delivery has centralized, especially with the confines of needle phobias and associated pain related to traditional injections, and the existing limitations associated with oral drug delivery. Highlighted within is the possibility of further developing transdermal drug delivery for chronic pain treatment using iontophoresis-based microneedle array patches. A concerted effort was made to review critically all available therapies designed for the treatment of chronic pain. The drug delivery systems developed for this purpose and nondrug routes are elaborated on, in a systematic manner. Recent developments and future goals in transdermal delivery as a means to overcome the individual limitations of the aforementioned delivery routes are represented as well. The approval of patch-like devices that contain both the microelectronic-processing mechanism and the active medicament in a small portable device is still awaited by the pharmaceutical industry. This anticipated platform may provide transdermal electro-activated and electro-modulated drug delivery systems a feasible attempt in chronic pain treatment. Iontophoresis has been proven an effective mode used to administer ionized drugs in physiotherapeutic, diagnostic, and dermatological applications and may be an encouraging probability for the development of devices and aids in the treatment of chronic pain. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  1. 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..

  2. Magnetic control of potential microrobotic drug delivery systems: nanoparticles, magnetotactic bacteria and self-propelled microjets.

    Science.gov (United States)

    Khalil, Islam S M; Magdanz, Veronika; Sanchez, Samuel; Schmidt, Oliver G; Abelmann, Leon; Misra, Sarthak

    2013-01-01

    Development of targeted drug delivery systems using magnetic microrobots increases the therapeutic indices of drugs. These systems have to be incorporated with precise motion controllers. We demonstrate closed-loop motion control of microrobots under the influence of controlled magnetic fields. Point-to-point motion control of a cluster of iron oxide nanoparticles (diameter of 250 nm) is achieved by pulling the cluster towards a reference position using magnetic field gradients. Magnetotactic bacterium (MTB) is controlled by orienting the magnetic fields towards a reference position. MTB with membrane length of 5 µm moves towards the reference position using the propulsion force generated by its flagella. Similarly, self-propelled microjet with length of 50 µm is controlled by directing the microjet towards a reference position by external magnetic torque. The microjet moves along the field lines using the thrust force generated by the ejecting oxygen bubbles from one of its ends. Our control system positions the cluster of nanoparticles, an MTB and a microjet at an average velocity of 190 µm/s, 28 µm/s, 90 µm/s and within an average region-of-convergence of 132 µm, 40 µm, 235 µm, respectively.

  3. 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.

  4. Specialty flat-top beam delivery fibers with controlled beam parameter product

    Science.gov (United States)

    Jollivet, C.; Farley, K.; Conroy, M.; Abramczyk, J.; Belke, S.; Becker, F.; Tankala, K.

    2016-03-01

    Beam delivery fibers have been used widely for transporting the optical beams from the laser to the subject of irradiation in a variety of markets including industrial, medical and defense applications. Standard beam delivery fibers range from 50 to 1500 μm core diameter and are used to guide CW or pulsed laser light, generated by solid state, fiber or diode lasers. Here, we introduce a novel fiber technology capable of simultaneously controlling the beam profile and the angular divergence of single-mode (SM) and multi-mode (MM) beams using a single-optical fiber. Results of beam transformation from a SM to a MM beam with flat-top intensity profile are presented in the case of a controlled BPP at 3.8 mm*mrad. The scaling capabilities of this flat-top fiber design to achieve a range of BPP values while ensuring a flat-top beam profile are discussed. In addition, we demonstrate, for the first time to the best of our knowledge, the homogenizer capabilities of this novel technology, able to transform random MM beams into uniform flat-top beam profiles with very limited impact on the beam brightness. This study is concluded with a discussion on the scalability of this fiber technology to fit from 50 up to 1500 μm core fibers and its potential for a broader range of applications.

  5. Facultative control of matrix production optimizes competitive fitness in Pseudomonas aeruginosa PA14 biofilm models.

    Science.gov (United States)

    Madsen, Jonas S; Lin, Yu-Cheng; Squyres, Georgia R; Price-Whelan, Alexa; de Santiago Torio, Ana; Song, Angela; Cornell, William C; Sørensen, Søren J; Xavier, Joao B; Dietrich, Lars E P

    2015-12-01

    As biofilms grow, resident cells inevitably face the challenge of resource limitation. In the opportunistic pathogen Pseudomonas aeruginosa PA14, electron acceptor availability affects matrix production and, as a result, biofilm morphogenesis. The secreted matrix polysaccharide Pel is required for pellicle formation and for colony wrinkling, two activities that promote access to O2. We examined the exploitability and evolvability of Pel production at the air-liquid interface (during pellicle formation) and on solid surfaces (during colony formation). Although Pel contributes to the developmental response to electron acceptor limitation in both biofilm formation regimes, we found variation in the exploitability of its production and necessity for competitive fitness between the two systems. The wild type showed a competitive advantage against a non-Pel-producing mutant in pellicles but no advantage in colonies. Adaptation to the pellicle environment selected for mutants with a competitive advantage against the wild type in pellicles but also caused a severe disadvantage in colonies, even in wrinkled colony centers. Evolution in the colony center produced divergent phenotypes, while adaptation to the colony edge produced mutants with clear competitive advantages against the wild type in this O2-replete niche. In general, the structurally heterogeneous colony environment promoted more diversification than the more homogeneous pellicle. These results suggest that the role of Pel in community structure formation in response to electron acceptor limitation is unique to specific biofilm models and that the facultative control of Pel production is required for PA14 to maintain optimum benefit in different types of communities. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  6. Histone deacetylase 3 supports endochondral bone formation by controlling cytokine signaling and matrix remodeling

    Science.gov (United States)

    Carpio, Lomeli R.; Bradley, Elizabeth W.; McGee-Lawrence, Meghan E.; Weivoda, Megan M.; Poston, Daniel D.; Dudakovic, Amel; Xu, Ming; Tchkonia, Tamar; Kirkland, James L.; van Wijnen, Andre J.; Oursler, Merry Jo; Westendorf, Jennifer J.

    2017-01-01

    Histone deacetylase (HDAC) inhibitors are efficacious epigenetic-based therapies for some cancers and neurological disorders; however, each of these drugs inhibits multiple HDACs and has detrimental effects on the skeleton. To better understand how HDAC inhibitors affect endochondral bone formation, we conditionally deleted one of their targets, Hdac3, pre- and postnatally in type II collagen α1 (Col2α1)–expressing chondrocytes. Embryonic deletion was lethal, but postnatal deletion of Hdac3 delayed secondary ossification center formation, altered maturation of growth plate chondrocytes, and increased osteoclast activity in the primary spongiosa. HDAC3-deficient chondrocytes exhibited increased expression of cytokine and matrix-degrading genes (Il-6, Mmp3, Mmp13, and Saa3) and a reduced abundance of genes related to extracellular matrix production, bone development, and ossification (Acan, Col2a1, Ihh, and Col10a1). Histone acetylation increased at and near genes that had increased expression. The acetylation and activation of nuclear factor κB (NF-κB) were also increased in HDAC3-deficient chondrocytes. Increased cytokine signaling promoted autocrine activation of Janus kinase (JAK)–signal transducer and activator of transcription (STAT) and NF-κB pathways to suppress chondrocyte maturation, as well as paracrine activation of osteoclasts and bone resorption. Blockade of interleukin-6 (IL-6)–JAK–STAT signaling, NF-κB signaling, and bromodomain extraterminal proteins, which recognize acetylated lysines and promote transcriptional elongation, significantly reduced Il-6 and Mmp13 expression in HDAC3-deficient chondrocytes and secondary activation in osteoclasts. The JAK inhibitor ruxolitinib also reduced osteoclast activity in Hdac3 conditional knockout mice. Thus, HDAC3 controls the temporal and spatial expression of tissue-remodeling genes and inflammatory responses in chondrocytes to ensure proper endochondral ossification during development. PMID

  7. pH-responsive mesoporous silica nanoparticles employed in controlled drug delivery systems for cancer treatment

    International Nuclear Information System (INIS)

    Yang, Ke-Ni; Zhang, Chun-Qiu; Wang, Wei; Wang, Paul C.; Zhou, Jian-Ping; Liang, Xing-Jie

    2014-01-01

    In the fight against cancer, controlled drug delivery systems have emerged to enhance the therapeutic efficacy and safety of anti-cancer drugs. Among these systems, mesoporous silica nanoparticles (MSNs) with a functional surface possess obvious advantages and were thus rapidly developed for cancer treatment. Many stimuli-responsive materials, such as nanoparticles, polymers, and inorganic materials, have been applied as caps and gatekeepers to control drug release from MSNs. This review presents an overview of the recent progress in the production of pH-responsive MSNs based on the pH gradient between normal tissues and the tumor microenvironment. Four main categories of gatekeepers can respond to acidic conditions. These categories will be described in detail

  8. H∞ Control of Coronary Artery Input Time-Delay System via the Free-Matrix-Based Integral Inequality

    Directory of Open Access Journals (Sweden)

    Sha-sha Li

    2018-01-01

    Full Text Available The issue of H∞ control for the coronary artery input time-delay system with external disturbance is of concern. To further reduce conservation, we utilize the free-matrix-based integral inequality, Wirtinger-based integral inequality, and reciprocal convex combination approach to construct Lyapunov-Krasovskii function (LKF. Then a sufficient condition for controller design which can guarantee robust synchronization the coronary artery system is represented in terms of linear matrix inequality (LMI. Finally, a numerical example is exploited to show the effectiveness of the proposed methods.

  9. 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

  10. 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.

  11. Microfluidic assembly of monodisperse multistage pH-responsive polymer/porous silicon composites for precisely controlled multi-drug delivery.

    Science.gov (United States)

    Liu, Dongfei; Zhang, Hongbo; Herranz-Blanco, Bárbara; Mäkilä, Ermei; Lehto, Vesa-Pekka; Salonen, Jarno; Hirvonen, Jouni; Santos, Hélder A

    2014-05-28

    We report an advanced drug delivery platform for combination chemotherapy by concurrently incorporating two different drugs into microcompoistes with ratiometric control over the loading degree. Atorvastatin and celecoxib were selected as model drugs due to their different physicochemical properties and synergetic effect on colorectal cancer prevention and inhibition. To be effective in colorectal cancer prevention and inhibition, the produced microcomposite contained hypromellose acetate succinate, which is insoluble in acidic conditions but highly dissolving at neutral or alkaline pH conditions. Taking advantage of the large pore volume of porous silicon (PSi), atorvastatin was firstly loaded into the PSi matrix, and then encapsulated into the pH-responsive polymer microparticles containing celecoxib by microfluidics in order to obtain multi-drug loaded polymer/PSi microcomposites. The prepared microcomposites showed monodisperse size distribution, multistage pH-response, precise ratiometric controlled loading degree towards the simultaneously loaded drug molecules, and tailored release kinetics of the loaded cargos. This attractive microcomposite platform protects the payloads from being released at low pH-values, and enhances their release at higher pH-values, which can be further used for colon cancer prevention and treatment. Overall, the pH-responsive polymer/PSi-based microcomposite can be used as a universal platform for the delivery of different drug molecules for combination therapy. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A novel matrix approach for controlling the invariant densities of chaotic maps

    International Nuclear Information System (INIS)

    Rogers, Alan; Shorten, Robert; Heffernan, Daniel M.

    2008-01-01

    Recent work on positive matrices has resulted in a new matrix method for generating chaotic maps with arbitrary piecewise constant invariant densities, sometimes known as the inverse Frobenius-Perron problem (IFPP). In this paper, we give an extensive introduction to the IFPP, describing existing methods for solving it, and we describe our new matrix approach for solving the IFPP

  13. 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

  14. 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

  15. Modulation of electrostatic interactions to improve controlled drug delivery from nanogels.

    Science.gov (United States)

    Mauri, Emanuele; Chincarini, Giulia M F; Rigamonti, Riccardo; Magagnin, Luca; Sacchetti, Alessandro; Rossi, Filippo

    2017-03-01

    The synthesis of nanogels as devices capable to maintain the drug level within a desired range for a long and sustained period of time is a leading strategy in controlled drug delivery. However, with respect to the good results obtained with antibodies and peptides there are a lot of problems related to the quick and uncontrolled diffusion of small hydrophilic molecules through polymeric network pores. For these reasons research community is pointing toward the use of click strategies to reduce release rates of the linked drugs to the polymer chains. Here we propose an alternative method that considers the electrostatic interactions between polymeric chains and drugs to tune the release kinetics from nanogel network. The main advantage of these systems lies in the fact that the carried drugs are not modified and no chemical reactions take place during their loading and release. In this work we synthesized PEG-PEI based nanogels with different protonation degrees and the release kinetics with charged and uncharged drug mimetics (sodium fluorescein, SF, and rhodamine B, RhB) were studied. Moreover, also the effect of counterion used to induce protonation was taken into account in order to build a tunable drug delivery system able to provide multiple release rates with the same device. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Feed-Back Moisture Sensor Control for the Delivery of Water to Plants Cultivated in Space

    Science.gov (United States)

    Levine, Howard G.; Prenger, Jessica J.; Rouzan, Donna T.; Spinale, April C.; Murdoch, Trevor; Burtness, Kevin A.

    2005-01-01

    The development of a spaceflight-rated Porous Tube Insert Module (PTIM) nutrient delivery tray has facilitated a series of studies evaluating various aspects of water and nutrient delivery to plants as they would be cultivated in space. We report here on our first experiment using the PTIM with a software-driven feedback moisture sensor control strategy for maintaining root zone wetness level set-points. One-day-old wheat seedlings (Tritium aestivum cv Apogee; N=15) were inserted into each of three Substrate Compartments (SCs) pre-packed with 0.25-1 . mm Profile(TradeMark) substrate and maintained at root zone relative water content levels of 70, 80 and 90%. The SCs contained a bottom-situated porous tube around which a capillary mat was wrapped. Three Porous Tubes. were planted using similar protocols (but without the substrate) and also maintained at these three moisture level set-points. Half-strength modified Hoagland's nutrient solution was used to supply water and nutrients. Results on hardware performance, water usage rates and wheat developmental differences between the different experimental treatments are presented.

  17. Polyurethane intravaginal ring for controlled delivery of dapivirine, a nonnucleoside reverse transcriptase inhibitor of HIV-1.

    Science.gov (United States)

    Gupta, Kavita M; Pearce, Serena M; Poursaid, Azadeh E; Aliyar, Hyder A; Tresco, Patrick A; Mitchnik, Mark A; Kiser, Patrick F

    2008-10-01

    Women-controlled methods for prevention of male-to-female sexual transmission of HIV-1 are urgently needed. Providing inhibitory concentrations of HIV-1 reverse transcriptase inhibitors to impede the replication of the virus in the female genital tissue offers a mechanism for prophylaxis of HIV-1. To this end, an intravaginal ring device that can provide long duration delivery of dapivirine, a nonnucleoside reverse transcriptase inhibitor of HIV-1, was developed utilizing a medical-grade polyether urethane. Monolithic intravaginal rings were fabricated and sustained release with cumulative flux linear with time was demonstrated under sink conditions for a period of 30 days. The release rate was directly proportional to the amount of drug loaded. Another release study conducted for a week utilizing liposome dispersions as sink conditions, to mimic the partitioning of dapivirine into vaginal tissue, also demonstrated release rates constant with time. These results qualify polyether urethanes for development of intravaginal rings for sustained delivery of microbicidal agents. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

  18. 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.

  19. PLGA-lecithin-PEG core-shell nanoparticles for controlled drug delivery.

    Science.gov (United States)

    Chan, Juliana M; Zhang, Liangfang; Yuet, Kai P; Liao, Grace; Rhee, June-Wha; Langer, Robert; Farokhzad, Omid C

    2009-03-01

    Current approaches to encapsulate and deliver therapeutic compounds have focused on developing liposomal and biodegradable polymeric nanoparticles (NPs), resulting in clinically approved therapeutics such as Doxil/Caelyx and Genexol-PM, respectively. Our group recently reported the development of biodegradable core-shell NP systems that combined the beneficial properties of liposomal and polymeric NPs for controlled drug delivery. Herein we report the parameters that alter the biological and physicochemical characteristics, stability, drug release properties and cytotoxicity of these core-shell NPs. We further define scalable processes for the formulation of these NPs in a reproducible manner. These core-shell NPs consist of (i) a poly(D,L-lactide-co-glycolide) hydrophobic core, (ii) a soybean lecithin monolayer, and (iii) a poly(ethylene glycol) shell, and were synthesized by a modified nanoprecipitation method combined with self-assembly. Preparation of the NPs showed that various formulation parameters such as the lipid/polymer mass ratio and lipid/lipid-PEG molar ratio controlled NP physical stability and size. We encapsulated a model chemotherapy drug, docetaxel, in the NPs and showed that the amount of lipid coverage affected its drug release kinetics. Next, we demonstrated a potentially scalable process for the formulation, purification, and storage of NPs. Finally, we tested the cytotoxicity using MTT assays on two model human cell lines, HeLa and HepG2, and demonstrated the biocompatibility of these particles in vitro. Our data suggest that the PLGA-lecithin-PEG core-shell NPs may be a useful new controlled release drug delivery system.

  20. 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

  1. Dual stimuli-responsive nano-vehicles for controlled drug delivery: mesoporous silica nanoparticles end-capped with natural chitosan.

    Science.gov (United States)

    Hakeem, Abdul; Duan, Ruixue; Zahid, Fouzia; Dong, Chao; Wang, Boya; Hong, Fan; Ou, Xiaowen; Jia, Yongmei; Lou, Xiaoding; Xia, Fan

    2014-11-11

    Herein, we report natural chitosan end-capped MCM-41 type MSNPs as novel, dual stimuli, responsive nano-vehicles for controlled anticancer drug delivery. The chitosan nanovalves tightly close the pores of the MSNPs to control premature cargo release under physiological conditions but respond to lysozyme and acidic media to release the trapped cargo.

  2. 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

    This paper presents a new sensorless vector control system for high performance induction motor drives fed by a matrix converter with a non-linearity compensation and disturbance observer. The nonlinear voltage distortion that is caused by communication delay and on-state voltage drop in switching...

  3. 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...

  4. 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.

  5. 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.

  6. Partially polymerized liposomes: stable against leakage yet capable of instantaneous release for remote controlled drug delivery

    Energy Technology Data Exchange (ETDEWEB)

    Qin Guoting; Li Zheng; Xia Rongmin; Li Feng; O' Neill, Brian E; Li, King C [Department of Radiology, The Methodist Hospital Research Institute, Houston, TX 77030 (United States); Goodwin, Jessica T; Khant, Htet A; Chiu, Wah, E-mail: zli@tmhs.org, E-mail: kli@tmhs.org [National Center for Macromolecular Imaging, Baylor College of Medicine, Houston, TX 77030 (United States)

    2011-04-15

    A critical issue for current liposomal carriers in clinical applications is their leakage of the encapsulated drugs that are cytotoxic to non-target tissues. We have developed partially polymerized liposomes composed of polydiacetylene lipids and saturated lipids. Cross-linking of the diacetylene lipids prevents the drug leakage even at 40 deg. C for days. These inactivated drug carriers are non-cytotoxic. Significantly, more than 70% of the encapsulated drug can be instantaneously released by a laser that matches the plasmon resonance of the tethered gold nanoparticles on the liposomes, and the therapeutic effect was observed in cancer cells. The remote activation feature of this novel drug delivery system allows for precise temporal and spatial control of drug release.

  7. 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.

  8. Candidate Mission from Planet Earth control and data delivery system architecture

    Science.gov (United States)

    Shapiro, Phillip; Weinstein, Frank C.; Hei, Donald J., Jr.; Todd, Jacqueline

    1992-01-01

    Using a structured, experienced-based approach, Goddard Space Flight Center (GSFC) has assessed the generic functional requirements for a lunar mission control and data delivery (CDD) system. This analysis was based on lunar mission requirements outlined in GSFC-developed user traffic models. The CDD system will facilitate data transportation among user elements, element operations, and user teams by providing functions such as data management, fault isolation, fault correction, and link acquisition. The CDD system for the lunar missions must not only satisfy lunar requirements but also facilitate and provide early development of data system technologies for Mars. Reuse and evolution of existing data systems can help to maximize system reliability and minimize cost. This paper presents a set of existing and currently planned NASA data systems that provide the basic functionality. Reuse of such systems can have an impact on mission design and significantly reduce CDD and other system development costs.

  9. 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.))

  10. Quadratus Lumborum Block Versus Transversus Abdominis Plane Block for Postoperative Pain After Cesarean Delivery: A Randomized Controlled Trial.

    Science.gov (United States)

    Blanco, Rafael; Ansari, Tarek; Riad, Waleed; Shetty, Nanda

    Effective postoperative analgesia after cesarean delivery enhances early recovery, ambulation, and breastfeeding. In a previous study, we established the effectiveness of the quadratus lumborum block in providing pain relief after cesarean delivery compared with patient-controlled analgesia (morphine). In the current study, we hypothesized that this method would be equal to or better than the transversus abdominis plane block with regard to pain relief and its duration of action after cesarean delivery. Between April 2015 and August 2015, we randomized 76 patients scheduled for elective cesarean delivery under spinal anesthesia to receive the quadratus lumborum block or the transversus abdominis plane block for postoperative pain relief. This trial was registered prospectively (NCT 02489851) [corrected]. Patients in the quadratus lumborum block group used significantly less morphine than the transversus abdominis plane block group (P consumption and demands than transversus abdominis plane blocks after cesarean section. This effect was observed up to 48 hours postoperatively.

  11. 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

  12. Biohydrogels with magnetic nanoparticles as crosslinker: characteristics and potential use for controlled antitumor drug-delivery.

    Science.gov (United States)

    Barbucci, Rolando; Giani, Gabriele; Fedi, Serena; Bottari, Severino; Casolaro, Mario

    2012-12-01

    Hybrid magnetic hydrogels are of interest for applications in biomedical science as controlled drug-delivery systems. We have developed a strategy to obtain novel hybrid hydrogels with magnetic nanoparticles (NPs) of CoFe(2)O(3) and Fe(3)O(4) as crosslinker agents of carboxymethylcellulose (CMC) or hyaluronic acid (HYAL) polymers and we have tested these systems for controlled doxorubicin release. The magnetic NPs are functionalized with (3-aminopropyl)trimethoxysilane (APTMS) in order to introduce amino groups on the surface. The amino coating is determined and quantified by standard Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy methods, and by cyclic voltammetry, a novel approach that permits us to look at the solution properties of the functionalized NPs. The gel formation involves the creation of an amide bond between the carboxylic groups of CMC or HYAL and the amine groups of functionalized NPs, which work as crosslinking agents of the polymer chains. The hybrid hydrogels are chemically and morphologically characterized. The rheological and the water uptake properties of the hydrogels are also investigated. Under the application of an alternating magnetic field, the CMC-HYAL hybrid hydrogel previously loaded with doxorubicin shows a drug release greater than that showed by the CMC-HYAL hydrogel crosslinked with 1,3-diaminopropane. In conclusion, the presence of magnetic NPs makes the synthesized hybrid hydrogels suitable for application as a drug-delivery system by means of alternating magnetic fields. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  13. 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

  14. 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......, villous maturity, extent of maternal intervillous space and thickness of intervascular tissue layers. Placentae were from pregnancies (37-42 wk) which were either uncomplicated (control group) or complicated by diabetes mellitus (diabetic group, White class D) which was reasonably well controlled in terms......, diabetic placentae were 17% heavier and showed shorter fetal plasma distances (30%) and larger fetal capillaries (volume 45%, surface 39% and length 30% greater). Mode of delivery had significant main and interaction effects on stromal diffusion distance (25% greater in vaginal deliveries...

  15. 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.

  16. 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.

  17. A closed-loop anesthetic delivery system for real-time control of burst suppression

    Science.gov (United States)

    Liberman, Max Y.; Ching, ShiNung; Chemali, Jessica; Brown, Emery N.

    2013-08-01

    Objective. There is growing interest in using closed-loop anesthetic delivery (CLAD) systems to automate control of brain states (sedation, unconsciousness and antinociception) in patients receiving anesthesia care. The accuracy and reliability of these systems can be improved by using as control signals electroencephalogram (EEG) markers for which the neurophysiological links to the anesthetic-induced brain states are well established. Burst suppression, in which bursts of electrical activity alternate with periods of quiescence or suppression, is a well-known, readily discernible EEG marker of profound brain inactivation and unconsciousness. This pattern is commonly maintained when anesthetics are administered to produce a medically-induced coma for cerebral protection in patients suffering from brain injuries or to arrest brain activity in patients having uncontrollable seizures. Although the coma may be required for several hours or days, drug infusion rates are managed inefficiently by manual adjustment. Our objective is to design a CLAD system for burst suppression control to automate management of medically-induced coma. Approach. We establish a CLAD system to control burst suppression consisting of: a two-dimensional linear system model relating the anesthetic brain level to the EEG dynamics; a new control signal, the burst suppression probability (BSP) defining the instantaneous probability of suppression; the BSP filter, a state-space algorithm to estimate the BSP from EEG recordings; a proportional-integral controller; and a system identification procedure to estimate the model and controller parameters. Main results. We demonstrate reliable performance of our system in simulation studies of burst suppression control using both propofol and etomidate in rodent experiments based on Vijn and Sneyd, and in human experiments based on the Schnider pharmacokinetic model for propofol. Using propofol, we further demonstrate that our control system reliably

  18. Real-time depth monitoring and control of laser machining through scanning beam delivery system

    International Nuclear Information System (INIS)

    Ji, Yang; Grindal, Alexander W; Fraser, James M; Webster, Paul J L

    2015-01-01

    Scanning optics enable many laser applications in manufacturing because their low inertia allows rapid movement of the process beam across the sample. We describe our method of inline coherent imaging for real-time (up to 230 kHz) micron-scale (7–8 µm axial resolution) tracking and control of laser machining depth through a scanning galvo-telecentric beam delivery system. For 1 cm trench etching in stainless steel, we collect high speed intrapulse and interpulse morphology which is useful for further understanding underlying mechanisms or comparison with numerical models. We also collect overall sweep-to-sweep depth penetration which can be used for feedback depth control. For trench etching in silicon, we show the relationship of etch rate with average power and scan speed by computer processing of depth information without destructive sample post-processing. We also achieve three-dimensional infrared continuous wave (modulated) laser machining of a 3.96 × 3.96 × 0.5 mm 3 (length × width × maximum depth) pattern on steel with depth feedback. To the best of our knowledge, this is the first successful demonstration of direct real-time depth monitoring and control of laser machining with scanning optics. (paper)

  19. 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.

  20. Congestion Control for a Fair Packet Delivery in WSN: From a Complex System Perspective

    Directory of Open Access Journals (Sweden)

    Daniela Aguirre-Guerrero

    2014-01-01

    Full Text Available In this work, we propose that packets travelling across a wireless sensor network (WSN can be seen as the active agents that make up a complex system, just like a bird flock or a fish school, for instance. From this perspective, the tools and models that have been developed to study this kind of systems have been applied. This is in order to create a distributed congestion control based on a set of simple rules programmed at the nodes of the WSN. Our results show that it is possible to adapt the carried traffic to the network capacity, even under stressing conditions. Also, the network performance shows a smooth degradation when the traffic goes beyond a threshold which is settled by the proposed self-organized control. In contrast, without any control, the network collapses before this threshold. The use of the proposed solution provides an effective strategy to address some of the common problems found in WSN deployment by providing a fair packet delivery. In addition, the network congestion is mitigated using adaptive traffic mechanisms based on a satisfaction parameter assessed by each packet which has impact on the global satisfaction of the traffic carried by the WSN.

  1. 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.

  2. AND logic-like pH- and light-dual controlled drug delivery by surface modified mesoporous silica nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Junwei; He, Zhaoshuai; Li, Biao; Cheng, Tanyu, E-mail: tycheng@shnu.edu.cn; Liu, Guohua

    2017-04-01

    Recently, the controlled drug delivery system has become a potential platform for biomedical application. Herein, we developed a pH and light-dual controlled cargo release system exhibiting AND logic based on MCM-41 mesoporous silica nanoparticles, which was surface modified using β-cyclodextrin (β-CD) with imine bond and azobenzene derivative. The complex of β-CD and azobenzene derivative effectively blocked the cargo delivery in pH = 7.0 phosphate buffered saline (PBS) solution without 365 nm UV light irradiation. The cargo was fully released when both factors of acidic environment (pH = 5.0 PBS) and 365 nm UV light irradiation were satisfied, meanwhile only very little cargo was delivered if one factor was satisfied. The result also demonstrates that the opening/closing of the gate and the release of the cargo in small portions can be controlled. - Highlights: • A pH and light-dual controlled cargo release system exhibiting AND logic is developed. • The delivery system can release the cargo in small potions by controlling the opening/closing of the gate. • The delivery system realizes the controlled release in zebrafish.

  3. Fabrication and characterization of a rapid prototyped tissue engineering scaffold with embedded multicomponent matrix for controlled drug release

    Directory of Open Access Journals (Sweden)

    Chen M

    2012-08-01

    Full Text Available Muwan Chen,1,2 Dang QS Le,1,2 San Hein,2 Pengcheng Li,1 Jens V Nygaard,2 Moustapha Kassem,3 Jørgen Kjems,2 Flemming Besenbacher,2 Cody Bünger11Orthopaedic Research Lab, Aarhus University Hospital, Aarhus C, Denmark; 2Interdisciplinary Nanoscience Center (iNANO, Aarhus University, Aarhus C, Denmark; 3Department of Endocrinology and Metabolism, Odense University Hospital, Odense C, DenmarkAbstract: Bone tissue engineering implants with sustained local drug delivery provide an opportunity for better postoperative care for bone tumor patients because these implants offer sustained drug release at the tumor site and reduce systemic side effects. A rapid prototyped macroporous polycaprolactone 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, confocal imaging, and DNA quantification confirmed that immortalized human bone marrow-derived mesenchymal stem cells (hMSC-TERT cultured in the scaffold showed high cell viability and growth, and good cell infiltration to the pores of the scaffold. Alkaline phosphatase activity and osteocalcin staining showed that the scaffold was osteoinductive. The drug-release kinetics was investigated by loading doxorubicin into the scaffold. The scaffolds comprising nanoclay released up to 45% of the drug for up to 2 months, while the scaffold without nanoclay released 95% of the drug within 4 days. Therefore, this scaffold can fulfill the requirements for both bone tissue engineering and local sustained release of an anticancer drug in vitro. These results suggest that the scaffold can be used clinically in reconstructive surgery after bone tumor resection. Moreover, by changing the composition and amount of individual components, the scaffold can find application in other

  4. 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.

  5. Behavioral response and pain perception to computer controlled local anesthetic delivery system and cartridge syringe

    Directory of Open Access Journals (Sweden)

    T D Yogesh Kumar

    2015-01-01

    Full Text Available Aim: The present study evaluated and compared the pain perception, behavioral response, physiological parameters, and the role of topical anesthetic administration during local anesthetic administration with cartridge syringe and computer controlled local anesthetic delivery system (CCLAD. Design: A randomized controlled crossover study was carried out with 120 children aged 7-11 years. They were randomly divided into Group A: Receiving injection with CCLAD during first visit; Group B: Receiving injection with cartridge syringe during first visit. They were further subdivided into three subgroups based on the topical application used: (a 20% benzocaine; (b pressure with cotton applicator; (c no topical application. Pulse rate and blood pressure were recorded before and during injection procedure. Objective evaluation of disruptive behavior and subjective evaluation of pain were done using face legs activity cry consolability scale and modified facial image scale, respectively. The washout period between the two visits was 1-week. Results: Injections with CCLAD produced significantly lesser pain response, disruptive behavior (P < 0.001, and pulse rate (P < 0.05 when compared to cartridge syringe injections. Application of benzocaine produced lesser pain response and disruptive behavior when compared to the other two subgroups, although the result was not significant. Conclusion: Usage of techniques which enhance behavioral response in children like injections with CCLAD can be considered as a possible step toward achieving a pain-free pediatric dental practice.

  6. 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.

  7. A review on oral liquid as an emerging technology in controlled drug delivery system.

    Science.gov (United States)

    Torne, Sangmesh Raosaheb; Sheela, Angappan; Sarada, N C

    2017-12-03

    The oral liquid drug delivery system (OLDDS) remains as the primary choice of dosage form, though challenging, for the pharmaceutical scientists. In the last two decades, Oral Liquid Controlled Release (OLCR) formulation has gained a lot of attention because of its advantages over the conventional dosage forms. The world of nanotechnology has paved multiple ways to administer the drug through oral cavity in liquid dosage form with an additional advantage of control over the release. In the current study, the various approaches towards the same have been discussed comprehensively to understand the different mechanisms of OLCR. This review also emphasizes on the existing techniques and the developments that have been made to improve on its efficacy including various formulation related factors. It also provides valuable insights into the role of polymers in the development of OLCR formulation that can be used in the management of Gastroesophageal reflux disease (GERD). Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Work load, job control and risk of leaving work by sickness certification before delivery, Norway 1989.

    Science.gov (United States)

    Strand, K; Wergeland, E; Bjerkedal, T

    1997-09-01

    Sickness absence in pregnancy has been shown to be associated with strenuous working conditions and parity. So far, few studies have made adjustments for possible interaction and confounding. Such adjustments are needed to more precisely identify targets for preventive measures. We have, therefore, in a representative population of pregnant employees in Norway 1989, computed adjusted odds ratios for leaving work by sickness absence more than three (LSC > 3) and eight (LSC > 8) weeks before delivery according to working conditions identified as risk factors in earlier studies; adjusted for job control, domestic conditions and sickness absence the year prior to pregnancy. The cumulative percentage of LSC > 8 and LSC > 3 was 26.4 and 51.1. Ergonomically strenuous postures and heavy lifting increased the risk of both outcomes. In addition, shift work and hectic work pace increased the risk of LSC > 3. Influence on breaks reduced risk. Only para experienced reduced risk of LSC when working part-time. Sicklisting the year prior to pregnancy had no confounding effect, which suggest that pregnancy represents a new incompatibility with work. Preventive measures should address work postures and heavy lifting, as well as conditions influencing the woman's control with her time.

  9. 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.

  10. Fabrication and characterization of a rapid prototyped tissue engineering scaffold with embedded multicomponent matrix for controlled drug release

    Science.gov (United States)

    Chen, Muwan; Le, Dang QS; Hein, San; Li, Pengcheng; Nygaard, Jens V; Kassem, Moustapha; Kjems, Jørgen; Besenbacher, Flemming; Bünger, Cody

    2012-01-01

    Bone tissue engineering implants with sustained local drug delivery provide an opportunity for better postoperative care for bone tumor patients because these implants offer sustained drug release at the tumor site and reduce systemic side effects. A rapid prototyped macroporous polycaprolactone 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, confocal imaging, and DNA quantification confirmed that immortalized human bone marrow-derived mesenchymal stem cells (hMSC-TERT) cultured in the scaffold showed high cell viability and growth, and good cell infiltration to the pores of the scaffold. Alkaline phosphatase activity and osteocalcin staining showed that the scaffold was osteoinductive. The drug-release kinetics was investigated by loading doxorubicin into the scaffold. The scaffolds comprising nanoclay released up to 45% of the drug for up to 2 months, while the scaffold without nanoclay released 95% of the drug within 4 days. Therefore, this scaffold can fulfill the requirements for both bone tissue engineering and local sustained release of an anticancer drug in vitro. These results suggest that the scaffold can be used clinically in reconstructive surgery after bone tumor resection. Moreover, by changing the composition and amount of individual components, the scaffold can find application in other tissue engineering areas that need local sustained release of drug. PMID:22904634

  11. 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

    , the prevalence of any type of urinary incontinence in the primiparous group was 32.1%, compared to 13.8% in the control group. Adjusted OR¿=¿3.3 (95%CI¿=¿2.4-4.4). One year after delivery, the prevalence in the primiparous group was 29.3%, compared to 16.6% in the control group. Adjusted OR¿=¿2.5 (95%CI¿=¿1......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...

  12. 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...

  13. 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...

  14. Early pregnancy peripheral blood gene expression and risk of preterm delivery: a nested case control study

    Directory of Open Access Journals (Sweden)

    Muhie Seid Y

    2009-12-01

    Full Text Available Abstract Background Preterm delivery (PTD is a significant public health problem associated with greater risk of mortality and morbidity in infants and mothers. Pathophysiologic processes that may lead to PTD start early in pregnancy. We investigated early pregnancy peripheral blood global gene expression and PTD risk. Methods As part of a prospective study, ribonucleic acid was extracted from blood samples (collected at 16 weeks gestational age from 14 women who had PTD (cases and 16 women who delivered at term (controls. Gene expressions were measured using the GeneChip® Human Genome U133 Plus 2.0 Array. Student's T-test and fold change analysis were used to identify differentially expressed genes. We used hierarchical clustering and principle components analysis to characterize signature gene expression patterns among cases and controls. Pathway and promoter sequence analyses were used to investigate functions and functional relationships as well as regulatory regions of differentially expressed genes. Results A total of 209 genes, including potential candidate genes (e.g. PTGDS, prostaglandin D2 synthase 21 kDa, were differentially expressed. A set of these genes achieved accurate pre-diagnostic separation of cases and controls. These genes participate in functions related to immune system and inflammation, organ development, metabolism (lipid, carbohydrate and amino acid and cell signaling. Binding sites of putative transcription factors such as EGR1 (early growth response 1, TFAP2A (transcription factor AP2A, Sp1 (specificity protein 1 and Sp3 (specificity protein 3 were over represented in promoter regions of differentially expressed genes. Real-time PCR confirmed microarray expression measurements of selected genes. Conclusions PTD is associated with maternal early pregnancy peripheral blood gene expression changes. Maternal early pregnancy peripheral blood gene expression patterns may be useful for better understanding of PTD

  15. 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.

  16. Numerical algebra, matrix theory, differential-algebraic equations and control theory festschrift in honor of Volker Mehrmann

    CERN Document Server

    Bollhöfer, Matthias; Kressner, Daniel; Mehl, Christian; Stykel, Tatjana

    2015-01-01

    This edited volume highlights the scientific contributions of Volker Mehrmann, a leading expert in the area of numerical (linear) algebra, matrix theory, differential-algebraic equations and control theory. These mathematical research areas are strongly related and often occur in the same real-world applications. The main areas where such applications emerge are computational engineering and sciences, but increasingly also social sciences and economics. This book also reflects some of Volker Mehrmann's major career stages. Starting out working in the areas of numerical linear algebra (his first full professorship at TU Chemnitz was in "Numerical Algebra," hence the title of the book) and matrix theory, Volker Mehrmann has made significant contributions to these areas ever since. The highlights of these are discussed in Parts I and II of the present book. Often the development of new algorithms in numerical linear algebra is motivated by problems in system and control theory. These and his later major work on ...

  17. Formation of failure matrix and failure–free control algorithm for multi–sectioned Switched–reluctance drive

    International Nuclear Information System (INIS)

    Odnokopylov, G; Rozayev, I

    2014-01-01

    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

  18. Applications of Fourier transform infrared spectroscopy to quality control of the epoxy matrix

    Science.gov (United States)

    Antoon, M. K.; Starkey, K. M.; Koenig, J. L.

    1979-01-01

    The object of the paper is to demonstrate the utility of Fourier transform infrared (FT-IR) difference spectra for investigating the composition of a neat epoxy resin, hardener, and catalysts. The composition and degree of cross-linking of the cured matrix is also considered.

  19. A check valve controlled laser-induced microjet for uniform transdermal drug delivery

    Science.gov (United States)

    Ham, Hwi-chan; Jang, Hun-jae; Yoh, Jack J.

    2017-12-01

    A narrow nozzle ejects a microjet of 150 μm in diameter with a velocity of 140 m/s a by the laser-induced bubble expansion in the designed injector. The pulsed form of the driving force at a period of 10 Hz from the connected Er:YAG laser makes it possible for multiple microjet ejections aimed at delivery of drugs into a skin target. The pulsed actuation of the microjet generation is however susceptible to the air leak which can cause the outside air to enter into the momentarily de-pressurized nozzle, leading to a significant reduction of the microjet speed during the pulsed administering of the drug. In the present study, we designed a ball-check valve injector which is less prone to an unwanted air build up inside the nozzle by controlling the nozzle pressure to remain above ambient pressure at all times. The new device is rigorously compared against the reported performance of the previous injector and has shown to maintain about 97% of the initial microjet speed regardless of the number of shots administered; likewise, the drug penetration depth into a porcine skin is improved to 1.5 to 2.25 times the previously reported penetration depths.

  20. A check valve controlled laser-induced microjet for uniform transdermal drug delivery

    Directory of Open Access Journals (Sweden)

    Hwi-chan Ham

    2017-12-01

    Full Text Available A narrow nozzle ejects a microjet of 150 μm in diameter with a velocity of 140 m/s a by the laser-induced bubble expansion in the designed injector. The pulsed form of the driving force at a period of 10 Hz from the connected Er:YAG laser makes it possible for multiple microjet ejections aimed at delivery of drugs into a skin target. The pulsed actuation of the microjet generation is however susceptible to the air leak which can cause the outside air to enter into the momentarily de-pressurized nozzle, leading to a significant reduction of the microjet speed during the pulsed administering of the drug. In the present study, we designed a ball-check valve injector which is less prone to an unwanted air build up inside the nozzle by controlling the nozzle pressure to remain above ambient pressure at all times. The new device is rigorously compared against the reported performance of the previous injector and has shown to maintain about 97% of the initial microjet speed regardless of the number of shots administered; likewise, the drug penetration depth into a porcine skin is improved to 1.5 to 2.25 times the previously reported penetration depths.

  1. 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

  2. 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.

  3. [Optimum approach to delivery for control of premature birth (author's transl)].

    Science.gov (United States)

    Nieder, J; Lattorff, E

    1980-01-01

    Foetal condition and neonatal mortality of 637 prematurely born children with birth weights below 2,501 g were analysed, depending on modes of delivery, such as spontaneous birth, speculum delivery, use of forceps, manual support, and caesarean section. The clinical condition of the newborn, assessed five minutes from parturition by Apgar score 1, was found to depend primarily on birth weight rather than on the mode of delivery. The average Apgar values were lower for less mature newborns. While Apgar scores were worst for newborns after caesarean section delivery, the differences between approaches to delivery could not be statistically secured. Neonatal mortality went up, according to expectation, along with dropping birth weight. The mortality rate of premature births below 1,501 g was not affected by delivery modes. Prophylactic use of Shute forceps and speculum delivery appeared to be superior to spontaneous birth in the medium weight class, between 1,501 g and 2,000 g. Yet, not even here were the differences between clear postnatal mortality rates statistically secured. -Lowest mortality figures were recorded from spontaneous birth in the weight class between 2,001 g and 2,500 g, but significant differences were established only to speculum delivery. Premature newborns after caesarean section had poorer prospects than all variants of vaginal birth, but among the latter premature births from breech presentation were more endangered than others. Decisions as to vaginal, abdominal, spontaneous proprophylactically surgical approaches to premature deliveries should be taken for every individual case and due consideration of many factors.

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

    International Nuclear Information System (INIS)

    Jaiswal, Maneesh; Koul, Veena; Dinda, Amit K; Gupta, Asheesh

    2010-01-01

    A biodegradable semi-interpenetrating hydrogel network (semi-IPN) of polyacrylamide and gelatin was prepared using polycaprolactone diacrylate (mol. wt ∼ 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 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 t /M ∞ ≤ 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.

  5. Controlled delivery of pirfenidone through vitamin E-loaded contact lens ameliorates corneal inflammation.

    Science.gov (United States)

    Dixon, Phillip; Ghosh, Tanushri; Mondal, Kalyani; Konar, Aditya; Chauhan, Anuj; Hazra, Sarbani

    2018-06-01

    .20 ±  0.04. In vivo, the drug was available in the aqueous humor for up to 3 h. Gene expression of inflammatory cytokine IL-β1 and profibrotic growth factor TGF-β1 was significantly suppressed in corneas treated with pirfenidone contact lenses. A week after the alkali burn, the eyes with pirfenidone contact lenses showed significant improvement in corneal haze in comparison to the control eyes. About 50% of the drug loaded in the lens reached the aqueous humor compared to 1.3% with eye drops. Vitamin E-loaded contact lenses serve as a suitable platform for delivery of pirfenidone following alkali burn in rabbit eyes; positive pre-clinical outcome identifies it as promising therapy for addressing corneal inflammation and fibrosis. The bioavailability is about 40-fold higher for contact lenses compared to that for eye drops.

  6. 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.

  7. 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.

  8. H{sub 2}/H{infinity} control of flexible structures through linear matrix inequalities with pole placement

    Energy Technology Data Exchange (ETDEWEB)

    Lopes, Jean C. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)

    2009-07-01

    The objective of this work is to apply the H2/H{infinity} control technique using linear matrix inequalities and pole placement constraints to the flexible structures control problem. The H2/H{infinity}control is a technique to design a controller with mixed features of the H2 and H{infinity} control formulations, such as, optimal dynamical performance and robust performance. The Linear Matrix Inequalities allow formulating the problem as a convex optimization problem, and additional constraints can be included such as the pole placement. The pole placement requirement comes from the necessity of adjusting the transient response of the plant and ensuring a specific behavior in terms of speed and damping responses. The mathematical model used for this study is related to a flexible beam, with an applied disturbance and an actuator in different positions. The state-space matrices of the structure were obtained using the finite element method with the Euler-Bernoulli formulation of beams. The results showed that the pole placement constraints can improve the performance of the controller H2/H{infinity}. The Matlab was used for the computational implementation. (author)

  9. 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.

  10. 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.

  11. 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

  12. Matrix and reservoir-type multipurpose vaginal rings for controlled release of dapivirine and levonorgestrel.

    Science.gov (United States)

    Boyd, Peter; Fetherston, Susan M; McCoy, Clare F; Major, Ian; Murphy, Diarmaid J; Kumar, Sandeep; Holt, Jonathon; Brimer, Andrew; Blanda, Wendy; Devlin, Brid; Malcolm, R Karl

    2016-09-10

    A matrix-type silicone elastomer vaginal ring providing 28-day continuous release of dapivirine (DPV) - a lead candidate human immunodeficiency virus type 1 (HIV-1) microbicide compound - has recently demonstrated moderate levels of protection in two Phase III clinical studies. Here, next-generation matrix and reservoir-type silicone elastomer vaginal rings are reported for the first time offering simultaneous and continuous in vitro release of DPV and the contraceptive progestin levonorgestrel (LNG) over a period of between 60 and 180days. For matrix-type vaginal rings comprising initial drug loadings of 100, 150 or 200mg DPV and 0, 16 or 32mg LNG, Day 1 daily DPV release values were between 4132 and 6113μg while Day 60 values ranged from 284 to 454μg. Daily LNG release ranged from 129 to 684μg on Day 1 and 2-91μg on Day 60. Core-type rings comprising one or two drug-loaded cores provided extended duration of in vitro release out to 180days, and maintained daily drug release rates within much narrower windows (either 75-131μg/day or 37-66μg/day for DPV, and either 96-150μg/day or 37-57μg/day for LNG, depending on core ring configuration and ignoring initial lag release effect for LNG) compared with matrix-type rings. The data support the continued development of these devices as multi-purpose prevention technologies (MPTs) for HIV prevention and long-acting contraception. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Transfer matrix method for dynamics modeling and independent modal space vibration control design of linear hybrid multibody system

    Science.gov (United States)

    Rong, Bao; Rui, Xiaoting; Lu, Kun; Tao, Ling; Wang, Guoping; Ni, Xiaojun

    2018-05-01

    In this paper, an efficient method of dynamics modeling and vibration control design of a linear hybrid multibody system (MS) is studied based on the transfer matrix method. The natural vibration characteristics of a linear hybrid MS are solved by using low-order transfer equations. Then, by constructing the brand-new body dynamics equation, augmented operator and augmented eigenvector, the orthogonality of augmented eigenvector of a linear hybrid MS is satisfied, and its state space model expressed in each independent model space is obtained easily. According to this dynamics model, a robust independent modal space-fuzzy controller is designed for vibration control of a general MS, and the genetic optimization of some critical control parameters of fuzzy tuners is also presented. Two illustrative examples are performed, which results show that this method is computationally efficient and with perfect control performance.

  14. Bi-layered nanocomposite bandages for controlling microbial infections and overproduction of matrix metalloproteinase activity.

    Science.gov (United States)

    Anjana, J; Mohandas, Annapoorna; Seethalakshmy, S; Suresh, Maneesha K; Menon, Riju; Biswas, Raja; Jayakumar, R

    2018-04-15

    Chronic diabetic wounds is characterised by increased microbial contamination and overproduction of matrix metalloproteases that would degrade the extracellular matrix. A bi-layer bandage was developed, that promotes the inhibition of microbial infections and matrix metalloprotease (MMPs) activity. Bi-layer bandage containing benzalkonium chloride loaded gelatin nanoparticles (BZK GNPs) in chitosan-Hyaluronic acid (HA) as a bottom layer and sodium alendronate containing chitosan as top layer was developed. We hypothesized that the chitosan-gelatin top layer with sodium alendronate could inhibit the MMPs activity, whereas the chitosan-HA bottom layer with BZK GNPs (240±66nm) would enable the elimination of microbes. The porosity, swelling and degradation nature of the prepared Bi-layered bandage was studied. The bottom layer could degrade within 4days whereas the top layer remained upto 7days. The antimicrobial activity of the BZK NPs loaded bandage was determined using normal and clinical strains. Gelatin zymography shows that the proteolytic activity of MMP was inhibited by the bandage. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. 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.

  16. 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.

  17. 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

  18. Spontaneous vaginal delivery in the birth-chair versus in the conventional dorsal position: a matched controlled comparison.

    Science.gov (United States)

    Scholz, H S; Benedicic, C; Arikan, M G; Haas, J; Petru, E

    2001-09-17

    The aim of the study was to assess the effect of a birth-chair on obstetric outcome. We reviewed the hospital records of 220 consecutive pregnant women who gave birth on a birth-chair at our institution. The control group consisted of 440 pregnant women who preceded and followed the index cases and who had spontaneous vaginal deliveries in the conventional dorsal supine position. The controls were matched for parity and for the attending mid-wife. Patients who delivered in the birth-chair had significantly lower rates of episiotomy and manual separation of the placenta. The umbilical blood cord pH was significantly higher in neonates of the birth-chair group. The duration of labour, rate of perineal and vaginal injury, Apgar scores and rate of admission to a neonatal intermediate care unit were not influenced by the mode of delivery. Our data support previous studies that a birth-chair delivery may be a safe alternative to conventional delivery in the supine position.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Aerosol delivery of Akt controls protein translation in the lungs of dual luciferase reporter mice.

    Science.gov (United States)

    Tehrani, A M; Hwang, S-K; Kim, T-H; Cho, C-S; Hua, J; Nah, W-S; Kwon, J-T; Kim, J-S; Chang, S-H; Yu, K-N; Park, S-J; Bhandari, D R; Lee, K-H; An, G-H; Beck, G R; Cho, M-H

    2007-03-01

    Lung cancer has emerged as a leading cause of cancer death in the world; however, most of the current conventional therapies are not sufficiently effective in altering the progression of disease. Therefore, development of novel treatment approaches is needed. Although several genes and methods have been used for cancer gene therapy, a number of problems such as specificity, efficacy and toxicity reduce their application. This has led to re-emergence of aerosol gene delivery as a noninvasive method for lung cancer treatment. In this study, nano-sized glucosylated polyethyleneimine (GPEI) was used as a gene delivery carrier to investigate the effects of Akt wild type (WT) and kinase deficient (KD) on Akt-related signaling pathways and protein translation in the lungs of CMV- LucR-cMyc-IRES-LucF dual reporter mice. These mice are a powerful tool for the discrimination between cap-dependent/-independent protein translation. Aerosols containing self-assembled nano-sized GPEI/Akt WT or GPEI/Akt KD were delivered into the lungs of reporter mice through nose-only-inhalation-chamber with the aid of nebulizer. Aerosol delivery of Akt WT caused the increase of protein expression levels of Akt-related signals, whereas aerosol delivery of Akt KD did not. Furthermore, dual luciferase activity assay showed that aerosol delivery of Akt WT enhanced cap-dependent protein translation, whereas a reduction in cap-dependent protein translation by Akt KD was observed. Our results clearly showed that targeting Akt may be a good strategy for prevention as well as treatment of lung cancer. These studies suggest that our aerosol delivery is compatible for in vivo gene delivery which could be used as a noninvasive gene therapy in the future.

  5. Intra and Inter-Rater Reliability of Screening for Movement Impairments: Movement Control Tests from The Foundation Matrix

    Science.gov (United States)

    Mischiati, Carolina R.; Comerford, Mark; Gosford, Emma; Swart, Jacqueline; Ewings, Sean; Botha, Nadine; Stokes, Maria; Mottram, Sarah L.

    2015-01-01

    Pre-season screening is well established within the sporting arena, and aims to enhance performance and reduce injury risk. With the increasing need to identify potential injury with greater accuracy, a new risk assessment process has been produced; The Performance Matrix (battery of movement control tests). As with any new method of objective testing, it is fundamental to establish whether the same results can be reproduced between examiners and by the same examiner on consecutive occasions. This study aimed to determine the intra-rater test re-test and inter-rater reliability of tests from a component of The Performance Matrix, The Foundation Matrix. Twenty participants were screened by two experienced musculoskeletal therapists using nine tests to assess the ability to control movement during specific tasks. Movement evaluation criteria for each test were rated as pass or fail. The therapists observed participants real-time and tests were recorded on video to enable repeated ratings four months later to examine intra-rater reliability (videos rated two weeks apart). Overall test percentage agreement was 87% for inter-rater reliability; 98% Rater 1, 94% Rater 2 for test re-test reliability; and 75% for real-time versus video. Intraclass-correlation coefficients (ICCs) were excellent between raters (0.81) and within raters (Rater 1, 0.96; Rater 2, 0.88) but poor for real-time versus video (0.23). Reliability for individual components of each test was more variable: inter-rater, 68-100%; intra-rater, 88-100% Rater 1, 75-100% Rater 2; and real-time versus video 31-100%. Cohen’s Kappa values for inter-rater reliability were 0.0-1.0; intra-rater 0.6-1.0 for Rater 1; -0.1-1.0 for Rater 2; and -0.1-1 for real-time versus video. It is concluded that both inter and intra-rater reliability of tests in The Foundation Matrix are acceptable when rated by experienced therapists. Recommendations are made for modifying some of the criteria to improve reliability where

  6. Design of PDC Controllers by Matrix Reversibility for Synchronization of Yin and Yang Chaotic Takagi-Sugeno Fuzzy Henon Maps

    Directory of Open Access Journals (Sweden)

    Chun-Yen Ho

    2012-01-01

    Full Text Available This paper investigates the synchronization of Yin and Yang chaotic T-S fuzzy Henon maps via PDC controllers. Based on the Chinese philosophy, Yin is the decreasing, negative, historical, or feminine principle in nature, while Yang is the increasing, positive, contemporary, or masculine principle in nature. Yin and Yang are two fundamental opposites in Chinese philosophy. The Henon map is an invertible map; so the Henon maps with increasing and decreasing argument can be called the Yang and Yin Henon maps, respectively. Chaos synchronization of Yin and Yang T-S fuzzy Henon maps is achieved by PDC controllers. The design of PDC controllers is based on the linear invertible matrix theory. The T-S fuzzy model of Yin and Yang Henon maps and the design of PDC controllers are novel, and the simulation results show that the approach is effective.

  7. 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.

  8. Effects of Control Mode and R-Ratio on the Fatigue Behavior of a Metal Matrix Composite

    Science.gov (United States)

    2005-01-01

    Composite Because of their high specific stiffness and strength at elevated temperatures, continuously reinforced metal matrix composites (MMC's) are under consideration for a future generation of aeropropulsion systems. Since components in aeropropulsion systems experience substantial cyclic thermal and mechanical loads, the fatigue behavior of MMC's is of great interest. Almost without exception, previous investigations of the fatigue behavior of MMC's have been conducted in a tension-tension, load-controlled mode. This has been due to the fact that available material is typically less than 2.5-mm thick and, therefore, unable to withstand high compressive loads without buckling. Since one possible use of MMC's is in aircraft skins, this type of testing mode may be appropriate. However, unlike aircraft skins, most engine components are thick. In addition, the transient thermal gradients experienced in an aircraft engine will impose tension-compression loading on engine components, requiring designers to understand how the MMC will behave under fully reversed loading conditions. The increased thickness of the MMC may also affect the fatigue life. Traditionally, low-cycle fatigue (LCF) tests on MMC's have been performed in load control. For monolithic alloys, low-cycle fatigue tests are more typically performed in strain control. Two reasons justify this choice: (1) the critical volume from which cracks initiate and grow is generally small and elastically constrained by the larger surrounding volume of material, and (2) load-controlled, low-cycle fatigue tests of monolithics invariably lead to unconstrained ratcheting and localized necking--an undesired material response because the failure mechanism is far more severe than, and unrelated to, the fatigue mechanism being studied. It is unknown if this is the proper approach to composite testing. However, there is a lack of strain-controlled data on which to base any decisions. Consequently, this study addresses the

  9. 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.

  10. 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

  11. Matrix-controlled morphology evolution of Te inclusions in CdZnTe single crystal

    International Nuclear Information System (INIS)

    He, Yihui; Jie, Wanqi; Xu, Yadong; Wang, Tao; Zha, Gangqiang; Yu, Pengfei; Zheng, Xin; Zhou, Yan; Liu, Hang

    2012-01-01

    The fine morphologies of microscale Te inclusions in CdZnTe single crystal were investigated to reveal their shape evolution. Such inclusions from crystal ingots with different post-growth cooling rates were analyzed using scanning electron microscopy after surface treatment. A tetrakaidecahedron model embodying {1 0 0} and {1 1 1} matrix facets was developed to interpret the form of the Te inclusions. An entire shape evolution process was also proposed where the final configuration of the Te inclusions was a tetrahedron comprising {1 1 1}B facets.

  12. 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 ("2"2Na). Satisfactory results were obtained in the 3"r"d 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)

  13. 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.

  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. 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.

  16. 5-Fluorouracil Encapsulated Chitosan Nanoparticles for pH-Stimulated Drug Delivery: Evaluation of Controlled Release Kinetics

    Directory of Open Access Journals (Sweden)

    R. Seda Tığlı Aydın

    2012-01-01

    Full Text Available Nanoparticles consisting of human therapeutic drugs are suggested as a promising strategy for targeted and localized drug delivery to tumor cells. In this study, 5-fluorouracil (5-FU encapsulated chitosan nanoparticles were prepared in order to investigate potentials of localized drug delivery for tumor environment due to pH sensitivity of chitosan nanoparticles. Optimization of chitosan and 5-FU encapsulated nanoparticles production revealed 148.8±1.1 nm and 243.1±17.9 nm particle size diameters with narrow size distributions, which are confirmed by scanning electron microscope (SEM images. The challenge was to investigate drug delivery of 5-FU encapsulated chitosan nanoparticles due to varied pH changes. To achieve this objective, pH sensitivity of prepared chitosan nanoparticle was evaluated and results showed a significant swelling response for pH 5 with particle diameter of ∼450 nm. In vitro release studies indicated a controlled and sustained release of 5-FU from chitosan nanoparticles with the release amounts of 29.1–60.8% due to varied pH environments after 408 h of the incubation period. pH sensitivity is confirmed by mathematical modeling of release kinetics since chitosan nanoparticles showed stimuli-induced release. Results suggested that 5-FU encapsulated chitosan nanoparticles can be launched as pH-responsive smart drug delivery agents for possible applications of cancer treatments.

  17. Evaluation of hydrophobic materials as matrices for controlled-release drug delivery.

    Science.gov (United States)

    Quadir, Mohiuddin Abdul; Rahman, M Sharifur; Karim, M Ziaul; Akter, Sanjida; Awkat, M Talat Bin; Reza, Md Selim

    2003-07-01

    The present study was undertaken to evaluate the effect of different insoluble and erodable wax-lipid based materials and their content level on the release profile of drug from matrix systems. Matrix tablets of theophylline were prepared using carnauba wax, bees wax, stearic acid, cetyl alcohol, cetostearyl alcohol and glyceryl monostearate as rate-retarding agents by direct compression process. The release of theophylline from these hydrophobic matrices was studied over 8-hours in buffer media of pH 6.8. Statistically significant difference was found among the drug release profile from different matrices. The release kinetics was found to be governed by the type and content of hydrophobic materials in the matrix. At lower level of wax matrices (25%), a potential burst release was observed with all the materials being studied. Bees wax could not exert any sustaining action while an extensive burst release was found with carnauba wax at this hydrophobic load. Increasing the concentration of fat-wax materials significantly decreased the burst effect of drug from the matrix. At higher hydrophobic level (50% of the matrix), the rate and extent of drug release was significantly reduced due to increased tortuosity and reduced porosity of the matrix. Cetostearyl alcohol imparted the strongest retardation of drug release irrespective of fat-wax level. Numerical fits indicate that the Higuchi square root of time model was the most appropriate one for describing the release profile of theophylline from hydrophobic matrices. The release mechanism was also explored and explained with biexponential equation. Application of this model indicates that Fickian or case I kinetics is the predominant mechanism of drug release from these wax-lipid matrices. The mean dissolution time (MDT) was calculated for all the formulations and the highest MDT value was obtained with cetostearyl matrix. The greater sustaining activity of cetostearyl alcohol can be attributed to some level of

  18. 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.

  19. Size and targeting to PECAM vs ICAM control endothelial delivery, internalization and protective effect of multimolecular SOD conjugates.

    Science.gov (United States)

    Shuvaev, Vladimir V; Muro, Silvia; Arguiri, Evguenia; Khoshnejad, Makan; Tliba, Samira; Christofidou-Solomidou, Melpo; Muzykantov, Vladimir R

    2016-07-28

    Controlled endothelial delivery of SOD may alleviate abnormal local surplus of superoxide involved in ischemia-reperfusion, inflammation and other disease conditions. Targeting SOD to endothelial surface vs. intracellular compartments is desirable to prevent pathological effects of external vs. endogenous superoxide, respectively. Thus, SOD conjugated with antibodies to cell adhesion molecule PECAM (Ab/SOD) inhibits pro-inflammatory signaling mediated by endogenous superoxide produced in the endothelial endosomes in response to cytokines. Here we defined control of surface vs. endosomal delivery and effect of Ab/SOD, focusing on conjugate size and targeting to PECAM vs. ICAM. Ab/SOD enlargement from about 100 to 300nm enhanced amount of cell-bound SOD and protection against extracellular superoxide. In contrast, enlargement inhibited endocytosis of Ab/SOD and diminished mitigation of inflammatory signaling of endothelial superoxide. In addition to size, shape is important: endocytosis of antibody-coated spheres was more effective than that of polymorphous antibody conjugates. Further, targeting to ICAM provides higher endocytic efficacy than targeting to PECAM. ICAM-targeted Ab/SOD more effectively mitigated inflammatory signaling by intracellular superoxide in vitro and in animal models, although total uptake was inferior to that of PECAM-targeted Ab/SOD. Therefore, both geometry and targeting features of Ab/SOD conjugates control delivery to cell surface vs. endosomes for optimal protection against extracellular vs. endosomal oxidative stress, respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Flexible body stability analysis of Space Shuttle ascent flight control system by using lambda matrix solution techniques

    Science.gov (United States)

    Bown, R. L.; Christofferson, A.; Lardas, M.; Flanders, H.

    1980-01-01

    A lambda matrix solution technique is being developed to perform an open loop frequency analysis of a high order dynamic system. The procedure evaluates the right and left latent vectors corresponding to the respective latent roots. The latent vectors are used to evaluate the partial fraction expansion formulation required to compute the flexible body open loop feedback gains for the Space Shuttle Digital Ascent Flight Control System. The algorithm is in the final stages of development and will be used to insure that the feedback gains meet the design specification.

  1. Control Systems Analysis and Design via Matrix Inequalities and Interior Point Methods

    National Research Council Canada - National Science Library

    Boyd, Stephen P

    1998-01-01

    During the contract period we made considerable progress, developing new families of convex optimization problems for use in control engineering, forging new areas of control applications, and improvements in algorithms...

  2. 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

  3. Design and preparation of controlled floating gastroretentive ...

    African Journals Online (AJOL)

    gastroretentive delivery systems for enhanced fexofenadine ... Abstract. Purpose: To design and prepare effervescent floating gastroretentive tablets for controlled fexofenadine ..... Complex of Carbopol with Polyvinylpyrrolidone as a. Matrix for ...

  4. Matrix mechanics controls FHL2 movement to the nucleus to activate p21 expression

    Science.gov (United States)

    Nakazawa, Naotaka; Sathe, Aneesh R.; Shivashankar, G. V.; Sheetz, Michael P.

    2016-01-01

    Substrate rigidity affects many physiological processes through mechanochemical signals from focal adhesion (FA) complexes that subsequently modulate gene expression. We find that shuttling of the LIM domain (domain discovered in the proteins, Lin11, Isl-1, and Mec-3) protein four-and-a-half LIM domains 2 (FHL2) between FAs and the nucleus depends on matrix mechanics. In particular, on soft surfaces or after the loss of force, FHL2 moves from FAs into the nucleus and concentrates at RNA polymerase (Pol) II sites, where it acts as a transcriptional cofactor, causing an increase in p21 gene expression that will inhibit growth on soft surfaces. At the molecular level, shuttling requires a specific tyrosine in FHL2, as well as phosphorylation by active FA kinase (FAK). Thus, we suggest that FHL2 phosphorylation by FAK is a critical, mechanically dependent step in signaling from soft matrices to the nucleus to inhibit cell proliferation by increasing p21 expression. PMID:27742790

  5. 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)

  6. 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.

  7. 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

  8. 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.

  9. Polymer matrices obtained by ionizing radiation for using in controlled drug delivery systems; Matrizes polimericas obtidas mediante radiacao ionizante para sua utilizacao como sistemas de liberacao controlada de farmacos

    Energy Technology Data Exchange (ETDEWEB)

    Martellini, Flavia

    1998-07-01

    Two kinds of controlled drug delivery system were obtained by gamma radiation induced polymerization. One of the system was obtained from an acrylic derivative of acetaminophen (40-hydroxyacetanilide), by copolymerization of 4-(acryloyloxy) acetanilide and N,N-dimethylacrylamide (DMAA) in dimethylformamide solution with 0,16 kGy/h dose rate and 54 Gy dose. The values of reactivity rate, r-D{sub MAA} = 0,31 {+-} 0,02 e r{sub AOA} -0,07 {+-} 0,12, were determined by Fineman-Ross method. The acetaminophen hydrolysis was carried out in alkaline and enzymatic (trypsin) media. Another kind of drug delivery system studied was solvent controlled type, being the drug immobilized in the hydrogel,. The hydrogels prepared by radiation polymerization of acryloyl-L-propine methylester (A-Pro-OMe) with 10 Gy dose, showed thermosensible property, swelling or shrinking in water with decreased or increased temperatures. The hydrogels were obtained with different crosslink density, trimethylolpropane trimethacrylate, and the monomers N, N-dimethyl acrylamide (DMAA) and 2-cyanoethyl acrylate to study the influence of the composition in the drug delivery rate. It was verified that the porous size besides being a characteristic of the matrix composition, it was also temperature dependent (thermosensible). The analgesic drug acetaminophen was immobilized by entrapment and by physical adsorption into the hydrogels matrices for 'in vitro' study. The insulin was immobilized by adsorption for 'in vivo' study. (author)

  10. 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.

  11. 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.

  12. Randomized controlled trial of tranexamic acid among parturients at increased risk for postpartum hemorrhage undergoing cesarean delivery.

    Science.gov (United States)

    Sujata, Nambiath; Tobin, Raj; Kaur, Ranjeet; Aneja, Anjila; Khanna, Mona; Hanjoora, Vijay M

    2016-06-01

    To assess the effects of tranexamic acid among patients undergoing cesarean delivery who were at high risk of postpartum hemorrhage. Between August 1, 2012, and April 30, 2013, a randomized controlled trial was performed at a tertiary care center in India. Women undergoing an elective or emergency cesarean delivery who were at high risk for postpartum hemorrhage were enrolled. They were randomly assigned using sealed, opaque envelopes to receive 10mg/kg tranexamic acid or normal saline 10min before skin incision. Anesthesiologists were not masked to group assignment, but patients and obstetricians were. The primary outcome was need for additional uterotonic drugs within 24h after delivery. Analyses were by intention to treat. Thirty patients were assigned to each group. Additional uterotonic drugs were required in 7 (23%) patients assigned to tranexamic acid and 25 (83%) patients in the control group (Ptranexamic acid, administered before skin incision, significantly reduced the requirement for additional uterotonics among women at increased risk for postpartum hemorrhage. Clinical Trials Registry India: CTRI/2015/05/005752. Copyright © 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

  13. 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.

  14. 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)

  15. 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.

  16. Transdermal drug delivery

    Science.gov (United States)

    Prausnitz, Mark R.; Langer, Robert

    2009-01-01

    Transdermal drug delivery has made an important contribution to medical practice, but has yet to fully achieve its potential as an alternative to oral delivery and hypodermic injections. First-generation transdermal delivery systems have continued their steady increase in clinical use for delivery of small, lipophilic, low-dose drugs. Second-generation delivery systems using chemical enhancers, non-cavitational ultrasound and iontophoresis have also resulted in clinical products; the ability of iontophoresis to control delivery rates in real time provides added functionality. Third-generation delivery systems target their effects to skin’s barrier layer of stratum corneum using microneedles, thermal ablation, microdermabrasion, electroporation and cavitational ultrasound. Microneedles and thermal ablation are currently progressing through clinical trials for delivery of macromolecules and vaccines, such as insulin, parathyroid hormone and influenza vaccine. Using these novel second- and third-generation enhancement strategies, transdermal delivery is poised to significantly increase impact on medicine. PMID:18997767

  17. 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.

  18. 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).

  19. 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.

  20. Nuclear track microfilters in controlled drug delivery against chronic skin disease

    International Nuclear Information System (INIS)

    Gopalani, D.; Jodha, A.S.; Saravanan, S.; Kumar, S.

    2003-01-01

    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

  1. 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.

  2. 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

  3. 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

    Directory of Open Access Journals (Sweden)

    Murphy Deirdre J

    2012-09-01

    Full Text Available Abstract Background Instrumental 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/Design A 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. Discussion It 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 registration Current Controlled Trials ISRCTN72230496

  4. 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

  5. Anti-inflammatory Chitosan/Poly-γ-glutamic acid nanoparticles control inflammation while remodeling extracellular matrix in degenerated intervertebral disc.

    Science.gov (United States)

    Teixeira, Graciosa Q; Leite Pereira, Catarina; Castro, Flávia; Ferreira, Joana R; Gomez-Lazaro, Maria; Aguiar, Paulo; Barbosa, Mário A; Neidlinger-Wilke, Cornelia; Goncalves, Raquel M

    2016-09-15

    Intervertebral disc (IVD) degeneration is one of the most common causes of low back pain (LBP), the leading disorder in terms of years lived with disability. Inflammation can play a role in LPB, while impairs IVD regeneration. In spite of this, different inflammatory targets have been purposed in the context of IVD regeneration. Anti-inflammatory nanoparticles (NPs) of Chitosan and Poly-(γ-glutamic acid) with a non-steroidal anti-inflammatory drug, diclofenac (Df), were previously shown to counteract a pro-inflammatory response of human macrophages. Here, the effect of intradiscal injection of Df-NPs in degenerated IVD was evaluated. For that, Df-NPs were injected in a bovine IVD organ culture in pro-inflammatory/degenerative conditions, upon stimulation with needle-puncture and interleukin (IL)-1β. Df-NPs were internalized by IVD cells, down-regulating IL-6, IL-8, MMP1 and MMP3, and decreasing PGE2 production, compared with IL-1β-stimulated IVD punches. Interestingly, at the same time, Df-NPs promoted an up-regulation of extracellular matrix (ECM) proteins, namely collagen type II and aggrecan. Allover, this study suggests that IVD treatment with Df-NPs not only reduces inflammation, but also delays and/or decreases ECM degradation, opening perspectives to new intradiscal therapies for IVD degeneration, based on the modulation of inflammation. Degeneration of the IVD is an age-related progressive process considered to be the major cause of spine disorders. The pro-inflammatory environment and biomechanics of the degenerated IVD is a challenge for regenerative therapies. The novelty of this work is the intradiscal injection of an anti-inflammatory therapy based on Chitosan (Ch)/Poly-(γ-glutamic acid) (γ-PGA) nanoparticles (NPs) with an anti-inflammatory drug (diclofenac, Df), previously developed by us. This drug delivery system was tested in a pro-inflammatory/degenerative intervertebral disc ex vivo model. The main findings support the success of an anti

  6. Automatic Offline Formulation of Robust Model Predictive Control Based on Linear Matrix Inequalities Method

    Directory of Open Access Journals (Sweden)

    Longge Zhang

    2013-01-01

    Full Text Available Two automatic robust model predictive control strategies are presented for uncertain polytopic linear plants with input and output constraints. A sequence of nested geometric proportion asymptotically stable ellipsoids and controllers is constructed offline first. Then the feedback controllers are automatically selected with the receding horizon online in the first strategy. Finally, a modified automatic offline robust MPC approach is constructed to improve the closed system's performance. The new proposed strategies not only reduce the conservatism but also decrease the online computation. Numerical examples are given to illustrate their effectiveness.

  7. 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.

  8. TLCD Parametric Optimization for the Vibration Control of Building Structures Based on Linear Matrix Inequality

    OpenAIRE

    Huo, Linsheng; Qu, Chunxu; Li, Hongnan

    2014-01-01

    Passive liquid dampers have been used to effectively reduce the dynamic response of civil infrastructures subjected to earthquakes or strong winds. The design of liquid dampers for structural vibration control involves the determination of the optimal parameters. This paper presents an optimal design methodology for tuned liquid column dampers (TLCDs) based on the H∞ control theory. A practical structure, Dalian Xinghai Financial Business Building, is used to illustrate the feasibility of the...

  9. 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.

  10. Targeted delivery and controlled release of Paclitaxel for the treatment of lung cancer using single-walled carbon nanotubes

    International Nuclear Information System (INIS)

    Yu, Baodan; Tan, Li; Zheng, Runhui; Tan, Huo; Zheng, Lixia

    2016-01-01

    A new type of drug delivery system (DDS) based on single-walled carbon nanotubes (SWNTs) for controlled-release of the anti-cancer drug Paclitaxel (PTX) was constructed in this study. Chitosan (CHI) was non-covalently attached to the SWNTs to improve biocompatibility. Biocompatible hyaluronan was also combined to the outer CHI layer to realise the specific targeting property. The results showed that the release of PTX was pH-triggered and was better at lower pH (pH 5.5). The modified SWNTs showed a significant improvement in intracellular reactive oxygen species (ROS), which may have enhanced mitogen-activated protein kinase activation and further promoted cell apoptosis. The results of western blotting indicated that the apoptosis-related proteins were abundantly expressed in A549 cells. Lactate dehydrogenase (LDH) release assay and cell viability assay demonstrated that PTX-loaded SWNTs could destroy cell membrane integrity, thus inducing lower cell viability of the A549 cells. Thus, this targeting DDS could effectively inhibit cell proliferation and kill A549 cells, is a promising system for cancer therapy. - Highlights: • Chitosan and hyaluronan modified single-walled carbon nanotubes (SWNTs) were prepared for delivery of Paclitaxel (PTX). • Morphology, drug loading efficiency and drug release amount of the nanotubes were studied. • Cell viability, LDH, intracellular ROS levels and western blotting were evaluated. • The drug delivery system could effectively inhibit A549 cells proliferation.

  11. 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.

  12. Preparation of Biodegradable Oligo(lactides-Grafted Dextran Nanogels for Efficient Drug Delivery by Controlling Intracellular Traffic

    Directory of Open Access Journals (Sweden)

    Yuichi Ohya

    2018-05-01

    Full Text Available Nanogels, nanometer-sized hydrogel particles, have great potential as drug delivery carriers. To achieve effective drug delivery to the active sites in a cell, control of intracellular traffic is important. In this study, we prepared nanogels composed of dextran with oligolactide (OLA chains attached via disulfide bonds (Dex-g-SS-OLA that collapse under the reductive conditions of the cytosol to achieve efficient drug delivery. In addition, we introduced galactose (Gal residues on the nanogels, to enhance cellular uptake by receptor-mediated endocytosis, and secondary oligo-amine (tetraethylenepentamine groups, to aid in escape from endosomes via proton sponge effects. The obtained Dex-g-SS-OLA with attached Gal residues and tetraethylenepentamine (EI4 groups, EI4/Gal-Dex-g-SS-OLA, formed a nanogel with a hydrodynamic diameter of ca. 203 nm in phosphate-buffered solution. The collapse of the EI4/Gal-Dex-g-SS-OLA nanogels under reductive conditions was confirmed by a decrease in the hydrodynamic diameter in the presence of reductive agents. The specific uptake of the hydrogels into HepG2 cells and their intercellular behavior were investigated by flow cytometry and confocal laser scanning microscopy using fluorescence dye-labeled nanogels. Escape from the endosome and subsequent collapse in the cytosol of the EI4/Gal-Dex-g-SS-OLA were observed. These biodegradable nanogels that collapse under reductive conditions in the cytosol should have great potential as efficient drug carriers in, for example, cancer chemotherapy.

  13. Targeted delivery and controlled release of Paclitaxel for the treatment of lung cancer using single-walled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Baodan; Tan, Li; Zheng, Runhui; Tan, Huo, E-mail: tanhuo.2008@163.com; Zheng, Lixia, E-mail: 66593953@qq.com

    2016-11-01

    A new type of drug delivery system (DDS) based on single-walled carbon nanotubes (SWNTs) for controlled-release of the anti-cancer drug Paclitaxel (PTX) was constructed in this study. Chitosan (CHI) was non-covalently attached to the SWNTs to improve biocompatibility. Biocompatible hyaluronan was also combined to the outer CHI layer to realise the specific targeting property. The results showed that the release of PTX was pH-triggered and was better at lower pH (pH 5.5). The modified SWNTs showed a significant improvement in intracellular reactive oxygen species (ROS), which may have enhanced mitogen-activated protein kinase activation and further promoted cell apoptosis. The results of western blotting indicated that the apoptosis-related proteins were abundantly expressed in A549 cells. Lactate dehydrogenase (LDH) release assay and cell viability assay demonstrated that PTX-loaded SWNTs could destroy cell membrane integrity, thus inducing lower cell viability of the A549 cells. Thus, this targeting DDS could effectively inhibit cell proliferation and kill A549 cells, is a promising system for cancer therapy. - Highlights: • Chitosan and hyaluronan modified single-walled carbon nanotubes (SWNTs) were prepared for delivery of Paclitaxel (PTX). • Morphology, drug loading efficiency and drug release amount of the nanotubes were studied. • Cell viability, LDH, intracellular ROS levels and western blotting were evaluated. • The drug delivery system could effectively inhibit A549 cells proliferation.

  14. 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

  15. Conservation and Divergence in the Candida Species Biofilm Matrix Mannan-Glucan Complex Structure, Function, and Genetic Control.

    Science.gov (United States)

    Dominguez, Eddie; Zarnowski, Robert; Sanchez, Hiram; Covelli, Antonio S; Westler, William M; Azadi, Parastoo; Nett, Jeniel; Mitchell, Aaron P; Andes, David R

    2018-04-03

    Candida biofilms resist the effects of available antifungal therapies. Prior studies with Candida albicans biofilms show that an extracellular matrix mannan-glucan complex (MGCx) contributes to antifungal sequestration, leading to drug resistance. Here we implement biochemical, pharmacological, and genetic approaches to explore a similar mechanism of resistance for the three most common clinically encountered non- albicans Candida species (NAC). Our findings reveal that each Candida species biofilm synthesizes a mannan-glucan complex and that the antifungal-protective function of this complex is conserved. Structural similarities extended primarily to the polysaccharide backbone (α-1,6-mannan and β-1,6-glucan). Surprisingly, biochemical analysis uncovered stark differences in the branching side chains of the MGCx among the species. Consistent with the structural analysis, similarities in the genetic control of MGCx production for each Candida species also appeared limited to the synthesis of the polysaccharide backbone. Each species appears to employ a unique subset of modification enzymes for MGCx synthesis, likely accounting for the observed side chain diversity. Our results argue for the conservation of matrix function among Candida spp. While biogenesis is preserved at the level of the mannan-glucan complex backbone, divergence emerges for construction of branching side chains. Thus, the MGCx backbone represents an ideal drug target for effective pan- Candida species biofilm therapy. IMPORTANCE Candida species, the most common fungal pathogens, frequently grow as a biofilm. These adherent communities tolerate extremely high concentrations of antifungal agents, due in large part, to a protective extracellular matrix. The present studies define the structural, functional, and genetic similarities and differences in the biofilm matrix from the four most common Candida species. Each species synthesizes an extracellular mannan-glucan complex (MGCx) which

  16. Cell wall matrix polysaccharide distribution and cortical microtubule organization: two factors controlling mesophyll cell morphogenesis in land plants.

    Science.gov (United States)

    Sotiriou, P; Giannoutsou, E; Panteris, E; Apostolakos, P; Galatis, B

    2016-03-01

    This work investigates the involvement of local differentiation of cell wall matrix polysaccharides and the role of microtubules in the morphogenesis of mesophyll cells (MCs) of three types (lobed, branched and palisade) in the dicotyledon Vigna sinensis and the fern Asplenium nidus. Homogalacturonan (HGA) epitopes recognized by the 2F4, JIM5 and JIM7 antibodies and callose were immunolocalized in hand-made leaf sections. Callose was also stained with aniline blue. We studied microtubule organization by tubulin immunofluorescence and transmission electron microscopy. In both plants, the matrix cell wall polysaccharide distribution underwent definite changes during MC differentiation. Callose constantly defined the sites of MC contacts. The 2F4 HGA epitope in V. sinensis first appeared in MC contacts but gradually moved towards the cell wall regions facing the intercellular spaces, while in A. nidus it was initially localized at the cell walls delimiting the intercellular spaces, but finally shifted to MC contacts. In V. sinensis, the JIM5 and JIM7 HGA epitopes initially marked the cell walls delimiting the intercellular spaces and gradually shifted in MC contacts, while in A. nidus they constantly enriched MC contacts. In all MC types examined, the cortical microtubules played a crucial role in their morphogenesis. In particular, in palisade MCs, cortical microtubule helices, by controlling cellulose microfibril orientation, forced these MCs to acquire a truncated cone-like shape. Unexpectedly in V. sinensis, the differentiation of colchicine-affected MCs deviated completely, since they developed a cell wall ingrowth labyrinth, becoming transfer-like cells. The results of this work and previous studies on Zea mays (Giannoutsou et al., Annals of Botany 2013; 112: : 1067-1081) revealed highly controlled local cell wall matrix differentiation in MCs of species belonging to different plant groups. This, in coordination with microtubule-dependent cellulose microfibril

  17. 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.

  18. 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...

  19. 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

  20. 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

  1. Zein-based films and their usage for controlled delivery: Origin, classes and current landscape.

    Science.gov (United States)

    Zhang, Yong; Cui, Lili; Che, Xiaoxia; Zhang, Heng; Shi, Nianqiu; Li, Chunlei; Chen, Yan; Kong, Wei

    2015-05-28

    Zein is a class of alcohol-soluble prolamine proteins present in maize endosperm, which was approved as a generally recognized as safe (GRAS) excipient in 1985 by the United States Food and Drug Administration (US-FDA) for film coating of pharmaceuticals, e.g., tablets. Despite its long-term application in tablet production, effects of zein coating on tablet properties are still not fully understood. Moreover, many studies have also been conducted to illustrate its potential as an active ingredient of direct compressed tablets and film-based delivery carriers. In addition, the use of zein as a functional film coating material for new biomedical applications was also widely investigated in recent reports, which involved medical devices, nanoparticles, quantum dots and nanofibers. In this review, the present status of zein in the form of a thin film and uniform layer for use as a biomedical material is discussed. In addition, studies related to the behaviors and properties of zein films are also summarized and analyzed based on published works to gain mechanistic insights into the relationship between zein film and various improved profiles. This review will benefit future prospects of the use of zein film in drug delivery and biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. The in vivo study on the radiobiologic effect of prolonged delivery time to tumor control in C57BL mice implanted with Lewis lung cancer

    International Nuclear Information System (INIS)

    Wang, Xin; Xiong, Xiao-Peng; Lu, Jiade; Zhu, Guo-Pei; He, Shao-Qin; Hu, Chao-Su; Ying, Hong-Mei

    2011-01-01

    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. 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. The tumor growth delay of groups with prolonged delivery time was shorter than the group with single fraction of 18 Gy (P < 0.05). The tumor grow delay of groups with prolonged delivery time 30 min was longer than that of groups with prolonged delivery time 60 min P < 0.05). There was no significant difference between groups with same delivery time (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. 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

  7. 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.

  8. Development and optimization of methotrexate-loaded lipid-polymer hybrid nanoparticles for controlled drug delivery applications.

    Science.gov (United States)

    Tahir, Nayab; Madni, Asadullah; Balasubramanian, Vimalkumar; Rehman, Mubashar; Correia, Alexandra; Kashif, Prince Muhammad; Mäkilä, Ermei; Salonen, Jarno; Santos, Hélder A

    2017-11-25

    Lipid-polymer hybrid nanoparticles (LPHNPs) are emerging platforms for drug delivery applications. In the present study, methotrexate loaded LPHNPs consisted of PLGA and Lipoid S100 were fabricated by employing a single-step modified nanoprecipitation method combined with self-assembly. A three factor, three level Box Behnken design using Design-Expert ® software was employed to access the influence of three independent variables on the particle size, drug entrapment and percent drug release. The optimized formulation was selected through numeric optimization approach. The results were supported with the ANOVA analysis, regression equations and response surface plots. Transmission electron microscope images indicated the nanosized and spherical shape of the LPHNPs with fair size distribution. The nanoparticles ranged from 176 to 308nm, which increased with increased polymer concentration. The increase in polymer and lipid concentration also increased the drug entrapment efficiency. The in vitro drug release was in range 70.34-91.95% and the release mechanism follow the Higuchi model (R 2 =0.9888) and Fickian diffusion (n<0.5). The in vitro cytotoxicity assay and confocal microscopy of the optimized formulation demonstrate the good safety and better internalization of the LPHNPs. The cell antiproliferation showed the spatial and controlled action of the nanoformulation as compared to the plain drug solution. The results suggest that LPHNPs can be a promising delivery system envisioned to safe, stable and potentially controlled delivery of methotrexate to the cancer cells to achieve better therapeutic outcomes. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. 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.

  10. 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

  11. 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.

  12. A subset of neurons controls the permeability of the peritrophic matrix and midgut structure in Drosophila adults.

    Science.gov (United States)

    Kenmoku, Hiroyuki; Ishikawa, Hiroki; Ote, Manabu; Kuraishi, Takayuki; Kurata, Shoichiro

    2016-08-01

    The metazoan gut performs multiple physiological functions, including digestion and absorption of nutrients, and also serves as a physical and chemical barrier against ingested pathogens and abrasive particles. Maintenance of these functions and structures is partly controlled by the nervous system, yet the precise roles and mechanisms of the neural control of gut integrity remain to be clarified in Drosophila Here, we screened for GAL4 enhancer-trap strains and labeled a specific subsets of neurons, using Kir2.1 to inhibit their activity. We identified an NP3253 line that is susceptible to oral infection by Gram-negative bacteria. The subset of neurons driven by the NP3253 line includes some of the enteric neurons innervating the anterior midgut, and these flies have a disorganized proventricular structure with high permeability of the peritrophic matrix and epithelial barrier. The findings of the present study indicate that neural control is crucial for maintaining the barrier function of the gut, and provide a route for genetic dissection of the complex brain-gut axis in adults of the model organism Drosophila. © 2016. Published by The Company of Biologists Ltd.

  13. 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.

  14. The Relationship Between the Evolution of an Internal Structure and Drug Dissolution from Controlled-Release Matrix Tablets.

    Science.gov (United States)

    Kulinowski, Piotr; Hudy, Wiktor; Mendyk, Aleksander; Juszczyk, Ewelina; Węglarz, Władysław P; Jachowicz, Renata; Dorożyński, Przemysław

    2016-06-01

    In the last decade, imaging has been introduced as a supplementary method to the dissolution tests, but a direct relationship of dissolution and imaging data has been almost completely overlooked. The purpose of this study was to assess the feasibility of relating magnetic resonance imaging (MRI) and dissolution data to elucidate dissolution profile features (i.e., kinetics, kinetics changes, and variability). Commercial, hydroxypropylmethyl cellulose-based quetiapine fumarate controlled-release matrix tablets were studied using the following two methods: (i) MRI inside the USP4 apparatus with subsequent machine learning-based image segmentation and (ii) dissolution testing with piecewise dissolution modeling. Obtained data were analyzed together using statistical data processing methods, including multiple linear regression. As a result, in this case, zeroth order release was found to be a consequence of internal structure evolution (interplay between region's areas-e.g., linear relationship between interface and core), which eventually resulted in core disappearance. Dry core disappearance had an impact on (i) changes in dissolution kinetics (from zeroth order to nonlinear) and (ii) an increase in variability of drug dissolution results. It can be concluded that it is feasible to parameterize changes in micro/meso morphology of hydrated, controlled release, swellable matrices using MRI to establish a causal relationship between the changes in morphology and drug dissolution. Presented results open new perspectives in practical application of combined MRI/dissolution to controlled-release drug products.

  15. 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

  16. 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

  17. 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.

  18. 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 (<3%) fibers consisted of interleaved ellipsoid and cylindrical fragments. At higher dipyridamol content (3-5%) anomalous ellipsoid structures did not practically form, and fiber’s shape became cylindrical. The totality of morphological and structural characteristics determined the rate of dipyridamol diffusive transports. The simplified model of 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.

  19. Oral matrix tablet formulations for concomitant controlled release of anti-tubercular drugs: design and in vitro evaluations.

    Science.gov (United States)

    Hiremath, Praveen S; Saha, Ranendra N

    2008-10-01

    The aim of the present investigation was to develop controlled release (C.R.) matrix tablet formulations of rifampicin and isoniazid combination, to study the design parameters and to evaluate in vitro release characteristics. In the present study, a series of formulations were developed with different release rates and duration using hydrophilic polymers hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC). The duration of rifampicin and isoniazid release could be tailored by varying the polymer type, polymer ratio and processing techniques. Further, Eudragit L100-55 was incorporated in the matrix tablets to compensate for the pH-dependent release of rifampicin. Rifampicin was found to follow linear release profile with time from HPMC formulations. In case of formulations with HPC, there was an initial higher release in simulated gastric fluid (SGF) followed by zero order release profiles in simulated intestinal fluid (SIFsp) for rifampicin. The release of isoniazid was found to be predominantly by diffusion mechanism in case of HPMC formulations, and with HPC formulations release was due to combination of diffusion and erosion. The initial release was sufficiently higher for rifampicin from HPC thus ruling out the need to incorporate a separate loading dose. The initial release was sufficiently higher for isoniazid in all formulations. Thus, with the use of suitable polymer or polymer combinations and with the proper optimization of the processing techniques it was possible to design the C.R. formulations of rifampicin and isoniazid combination that could provide the sufficient initial release and release extension up to 24h for both the drugs despite of the wide variations in their physicochemical properties.

  20. 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.

  1. 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.

  2. 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 ...

  3. 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)

  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. 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.

  6. 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.

  7. Nanotechnology in dentistry: drug delivery systems for the control of biofilm-dependent oral diseases.

    Science.gov (United States)

    de Sousa, Francisco Fabio Oliveira; Ferraz, Camila; Rodrigues, Lidiany K Arla de Azevedo; Nojosa, Jacqueline de Santiago; Yamauti, Monica

    2014-01-01

    Dental disorders, such as caries, periodontal and endodontic diseases are major public health issues worldwide. In common, they are biofilm-dependent oral diseases, and the specific conditions of oral cavity may develop infectious foci that could affect other physiological systems. Efforts have been made to develop new treatment routes for the treatment of oral diseases, and therefore, for the prevention of some systemic illnesses. New drugs and materials have been challenged to prevent and treat these conditions, especially by means of bacteria elimination. "Recent progresses in understanding the etiology, epidemiology and microbiology of the microbial flora in those circumstances have given insight and motivated the innovation on new therapeutic approaches for the management of the oral diseases progression". Some of the greatest advances in the medical field have been based in nanosized systems, ranging from the drug release with designed nanoparticles to tissue scaffolds based on nanotechnology. These systems offer new possibilities for specific and efficient therapies, been assayed successfully in preventive/curative therapies to the oral cavity, opening new challenges and opportunities to overcome common diseases based on bacterial biofilm development. The aim of this review is to summarize the recent nanotechnological developments in the drug delivery field related to the prevention and treatment of the major biofilm-dependent oral diseases and to identify those systems, which may have higher potential for clinical use.

  8. Frequency-controlled wireless shape memory polymer microactuator for drug delivery application.

    Science.gov (United States)

    Zainal, M A; Ahmad, A; Mohamed Ali, M S

    2017-03-01

    This paper reports the wireless Shape-Memory-Polymer actuator operated by external radio frequency magnetic fields and its application in a drug delivery device. The actuator is driven by a frequency-sensitive wireless resonant heater which is bonded directly to the Shape-Memory-Polymer and is activated only when the field frequency is tuned to the resonant frequency of heater. The heater is fabricated using a double-sided Cu-clad Polyimide with much simpler fabrication steps compared to previously reported methods. The actuation range of 140 μm as the tip opening distance is achieved at device temperature 44 °C in 30 s using 0.05 W RF power. A repeatability test shows that the actuator's average maximum displacement is 110 μm and standard deviation of 12 μm. An experiment is conducted to demonstrate drug release with 5 μL of an acidic solution loaded in the reservoir and the device is immersed in DI water. The actuator is successfully operated in water through wireless activation. The acidic solution is released and diffused in water with an average release rate of 0.172 μL/min.

  9. Core Cross-linked Star Polymers for Temperature/pH Controlled Delivery of 5-Fluorouracil

    Directory of Open Access Journals (Sweden)

    Elizabeth Sánchez-Bustos

    2016-01-01

    Full Text Available RAFT polymerization with cross-linking was used to prepare core cross-linked star polymers bearing temperature sensitive arms. The arms consisted of a diblock copolymer containing N-isopropylacrylamide (NIPAAm and 4-methacryloyloxy benzoic acid (4MBA in the temperature sensitive block and poly(hexyl acrylate forming the second hydrophobic block, while ethyleneglycol dimethacrylate was used to form the core. The acid comonomer provides pH sensitivity to the arms and also increases the transition temperature of polyNIPAAm to values in the range of 40 to 46°C. Light scattering and atomic force microscopy studies suggest that loose core star polymers were obtained. The star polymers were loaded with 5-fluorouracil (5-FU, an anticancer agent, in values of up to 30 w/w%. In vitro release experiments were performed at different temperatures and pH values, as well as with heating and cooling temperature cycles. Faster drug release was obtained at 42°C or pH 6, compared to normal physiological conditions (37°C, pH 7.4. The drug carriers prepared acted as nanopumps changing the release kinetics of 5-FU when temperatures cycles were applied, in contrast with release rates at a constant temperature. The prepared core cross-linked star polymers represent advanced drug delivery vehicles optimized for 5-FU with potential application in cancer treatment.

  10. 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.

  11. 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.

  12. 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.

  13. Ingenious pH-sensitive dextran/mesoporous silica nanoparticles based drug delivery systems for controlled intracellular drug release.

    Science.gov (United States)

    Zhang, Min; Liu, Jia; Kuang, Ying; Li, Qilin; Zheng, Di-Wei; Song, Qiongfang; Chen, Hui; Chen, Xueqin; Xu, Yanglin; Li, Cao; Jiang, Bingbing

    2017-05-01

    In this work, dextran, a polysaccharide with excellent biocompatibility, is applied as the "gatekeeper" to fabricate the pH-sensitive dextran/mesoporous silica nanoparticles (MSNs) based drug delivery systems for controlled intracellular drug release. Dextran encapsulating on the surface of MSNs is oxidized by NaIO 4 to obtain three kinds of dextran dialdehydes (PADs), which are then coupled with MSNs via pH-sensitive hydrazone bond to fabricate three kinds of drug carriers. At pH 7.4, PADs block the pores to prevent premature release of anti-cancer drug doxorubicin hydrochloride (DOX). However, in the weakly acidic intracellular environment (pH∼5.5) the hydrazone can be ruptured; and the drug can be released from the carriers. The drug loading capacity, entrapment efficiency and release rates of the drug carriers can be adjusted by the amount of NaIO 4 applied in the oxidation reaction. And from which DOX@MSN-NH-N=C-PAD 10 is chosen as the most satisfactory one for the further in vitro cytotoxicity studies and cellular uptake studies. The results demonstrate that DOX@MSN-NH-N=C-PAD 10 with an excellent pH-sensitivity can enter HeLa cells to release DOX intracellular due to the weakly acidic pH intracellular and kill the cells. In our opinion, the ingenious pH-sensitive drug delivery systems have application potentials for cancer therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. The development and evaluation of a subcutaneous infusion delivery system based on osmotic pump control and gas drive.

    Science.gov (United States)

    Xie, Xiangyang; Yang, Yang; Yang, Yanfang; Li, Zhiping; Zhang, Hui; Chi, Qiang; Cai, Xingshi; Mei, Xingguo

    2016-09-01

    A novel, self-administration drug delivery system for subcutaneous infusion was developed and evaluated. The device includes two main components: an osmotic tablet controlled gas actuator and a syringe catheter system. The sodium carbonate in the osmotic pump tablet will release into the surround citric acid solution and produce CO 2 gas, which will drive the drug solution into subcutaneous tissue. The key formulation factors of the osmotic tablet that would influence the infusion profiles of the device were investigated by single factor exploration. The formulation was optimized via a response surface methodology. With an 18 ± 4 min of lag time, the delivery system was able to infuse at an approximate zero-order up to 5.90 ± 0.37 h with a precision of 9.0% RSD (n = 6). A linear correlation was found for the infusion profile and the fitting equation was Y = 0.014X - 0.004 (r = 0.998). A temperature change of 4 °C was found to modify the flow rate by about 12.0%. In vivo results demonstrated that the present subcutaneous infusion device was similar to the commercial infusion pump, and it could bring a long and constant ampicillin plasma level with minimized fluctuations.

  15. 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

  16. Preparation of Starch/Gelatin Blend Microparticles by a Water-in-Oil Emulsion Method for Controlled Release Drug Delivery.

    Science.gov (United States)

    Phromsopha, Theeraphol; Baimark, Yodthong

    2014-01-01

    Information on the preparation and properties of starch/gelatin blend microparticles with and without crosslinking for drug delivery is presented. The blend microparticles were prepared by the water-in-oil emulsion solvent diffusion method. Glutaraldehyde and methylene blue were used as the crosslinker and the water-soluble drug model, respectively. The blend microparticles were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and UV-Vis spectroscopy. The functional groups of the starch and gelatin blend matrices were determined from the FTIR spectra. Blend microparticles with a nearly spherical shape and internal porous structure were observed from SEM images. The average particle size of the gelatin microparticles depended on the crosslinker ratio but not on the starch/gelatin blend ratio. The in vitro drug release content significantly decreased as the crosslinker ratio increased and the starch blend ratio decreased. The results demonstrated that the starch/gelatin blend microparticles should be a useful controlled release delivery carrier for water-soluble drugs.

  17. Optimization of formulation and delivery technology of entomopathogenic fungi for malaria vector control

    NARCIS (Netherlands)

    Mnyone, L.L.

    2010-01-01

    Vector control is one of the most effective means of controlling mosquito-borne diseases such as malaria. The broad goal of this strategy is to protect individuals against infective mosquito bites and, at the community level, to reduce the intensity of disease transmission. With the deployment of

  18. 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.

  19. 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.

  20. Controlled Systemic Delivery by Polymeric Implants Enhances Tissue and Plasma Curcumin Levels Compared with Oral Administration

    Science.gov (United States)

    Bansal, Shyam S.; Kausar, Hina; Vadhanam, Manicka V.; Ravoori, Srivani; Gupta, Ramesh C.

    2012-01-01

    Curcumin possess potent anti-inflammatory and anti-proliferative activities but with poor biopharmaceutical attributes. To overcome these limitations, curcumin implants were developed and tissue (plasma, brain and liver) curcumin concentrations were measured in female ACI rats for 3 months. Biological efficacy of tissue levels achieved was analyzed by modulation of hepatic cytochromes. Curcumin implants exhibited diffusion-mediated biphasic release pattern with ~2-fold higher in vivo release as compared to in vitro. Plasma curcumin concentration from implants was ~3.3 ng/ml on day 1 which dropped to ~0.2 ng/ml after 3 months whereas only 0.2–0.3 ng/ml concentration was observed from 4–12 days with diet and was undetected subsequently. Almost 10 fold higher curcumin levels were observed in brain on day 1 from implants compared with diet (30.1±7.3 vs 2.7±0.8 ng/g) and were higher even after 90 days (7.7±3.8 vs 2.2±0.8 ng/g). Although, curcumin levels were similar in liver from both the routes (~25–30 ng/g from day 1–4 and ~10–15 ng/g at 90 days), implants were more efficacious in altering hepatic CYP1A1 levels and CYP3A4 activity at ~28 fold lower doses. Curcumin implants provided much higher plasma and tissue concentrations and are a viable alternative for delivery of curcumin to various organs like brain. PMID:22227368

  1. 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.

  2. 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

    2014-01-01

    Background 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. Methods Quarterly e-cigarette prices and sales and conventional cigarette prices from 2009 to 2012 were constructed from commercial retail store scanner data from 52 US 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. Results 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. Conclusions 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. PMID:24935898

  3. A Novel Delivery System for the Controlled Release of Antimicrobial Peptides: Citropin 1.1 and Temporin A

    Directory of Open Access Journals (Sweden)

    Urszula Piotrowska

    2018-05-01

    Full Text Available Antimicrobial peptides (AMPs are prospective therapeutic options for treating multiple-strain infections. However, clinical and commercial development of AMPs has some limitations due to their limited stability, low bioavailability, and potential hemotoxicity. The purpose of this study was to develop new polymeric carriers as highly controlled release devices for amphibian peptides citropin 1.1 (CIT and temporin A (TEMP. The release rate of the active pharmaceutical ingredients (APIs was strongly dependent on the API characteristics and the matrix microstructure. In the current work, we investigated the effect of the polymer microstructure on in vitro release kinetics of AMPs. Non-contact laser profilometry, scanning electron microscopy (SEM, and differential scanning calorimetry (DSC were used to determine the structural changes during matrix degradation. Moreover, geno- and cytotoxicity of the synthesized new carriers were evaluated. The in vitro release study of AMPs from the obtained non-toxic matrices shows that peptides were released with near-zero-order kinetics. The peptide “burst release” effect was not observed. New devices have reached the therapeutic concentration of AMPs within 24 h and maintained it for 28 days. Hence, our results suggest that these polymeric devices could be potentially used as therapeutic options for the treatment of local infections.

  4. Hydrogels containing redispersible spray-dried melatonin-loaded nanocapsules: a formulation for transdermal-controlled delivery

    Science.gov (United States)

    Hoffmeister, Cristiane RD; Durli, Taís L.; Schaffazick, Scheila R.; Raffin, Renata P.; Bender, Eduardo A.; Beck, Ruy CR; Pohlmann, Adriana R.; Guterres, Sílvia S.

    2012-05-01

    The aim of the present study was to develop a transdermal system for controlled delivery of melatonin combining three strategies: nanoencapsulation of melatonin, drying of melatonin-loaded nanocapsules, and incorporation of nanocapsules in a hydrophilic gel. Nanocapsules were prepared by interfacial deposition of the polymer and were spray-dried using water-soluble excipients. In vitro drug release profiles were evaluated by the dialysis bag method, and skin permeation studies were carried out using Franz cells with porcine skin as the membrane. The use of 10% ( w/ v) water-soluble excipients (lactose or maltodextrin) as spray-drying adjuvants furnished redispersible powders (redispersibility index approximately 1.0) suitable for incorporation into hydrogels. All formulations showed a better controlled in vitro release of melatonin compared with the melatonin solution. The best controlled release results were achieved with hydrogels prepared with dried nanocapsules (hydrogels > redispersed dried nanocapsules > nanocapsule suspension > melatonin solution). The skin permeation studies demonstrated a significant modulation of the transdermal melatonin permeation for hydrogels prepared with redispersible nanocapsules. In this way, the additive effect of the different approaches used in this study (nanoencapsulation, spray-drying, and preparation of semisolid dosage forms) allows not only the control of melatonin release, but also transdermal permeation.

  5. A novel and alternative approach to controlled release drug delivery system based on solid dispersion technique

    Directory of Open Access Journals (Sweden)

    Tapan Kumar Giri

    2012-12-01

    Full Text Available The solid dispersion method was originally used to improve the dissolution properties and the bioavailability of poorly water soluble drugs by dispersing them into water soluble carriers. In addition to the above, dissolution retardation through solid dispersion technique using water insoluble and water swellable polymer for the development of controlled release dosage forms has become a field of interest in recent years. Development of controlled release solid dispersion has a great advantage for bypassing the risk of a burst release of drug; since the structure of the solid dispersion is monolithic where drug molecules homogeneously disperse. Despite the remarkable potential and extensive research being conducted on controlled release solid dispersion system, commercialization and large scale production are limited. The author expects that recent technological advances may overcome the existing limitations and facilitate the commercial utilization of the techniques for manufacture of controlled release solid dispersions. This article begins with an overview of the different carriers being used for the preparation of controlled release solid dispersion and also different techniques being used for the purpose. Kinetics of drug release from these controlled release solid dispersions and the relevant mathematical modeling have also been reviewed in this manuscript.

  6. 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

  7. 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

  8. 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.

  9. Controlled drug delivery for glaucoma therapy using montmorillonite/Eudragit microspheres as an ion-exchange carrier

    Directory of Open Access Journals (Sweden)

    Tian SY

    2018-01-01

    Full Text Available Shuangyan Tian,1 Juan Li,1 Qi Tao,2,3 Yawen Zhao,1 Zhufen Lv,4 Fan Yang,1 Haoyun Duan,5 Yanzhong Chen,4 Qingjun Zhou,5 Dongzhi Hou1 1Guangdong Engineering and Technology Research Center of Topical Precise Drug Delivery System, College of Pharmacy, Department of Pharmaceutics, Guangdong Pharmaceutical University, 2CAS Key Laboratory of Mineralogy and Metallogeny, 3Guangdong Provincial Key Laboratory of Mineral Physics and Materials, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 4Guangdong Provincial Key Laboratory of Advanced Drug Delivery Systems, Guangdong Pharmaceutical University, Guangzhou, 5State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao, China Background: Glaucoma is a serious eye disease that can lead to loss of vision. Unfortunately, effective treatments are limited by poor bioavailability of antiglaucoma medicine due to short residence time on the preocular surface. Materials and methods: To solve this, we successfully prepared novel controlled-release ion-exchange microparticles to deliver betaxolol hydrochloride (BH. Montmorillonite/BH complex (Mt-BH was prepared by acidification-intercalation, and this complex was encapsulated in microspheres (Mt-BH encapsulated microspheres [BMEMs] by oil-in-oil emulsion–solvent evaporation method. The BH loaded into ion-exchange Mt was 47.45%±0.54%. After the encapsulation of Mt-BH into Eudragit microspheres, the encapsulation efficiency of BH into Eudragit microspheres was 94.35%±1.01% and BH loaded into Eudragit microspheres was 14.31%±0.47%. Results: Both Fourier transform infrared spectra and X-ray diffraction patterns indicated that BH was successfully intercalated into acid-Mt to form Mt-BH and then Mt-BH was encapsulated into Eudragit microspheres to obtain BMEMs. Interestingly, in vitro release duration of the prepared BMEMs was extended to 12 hours

  10. 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.

  11. 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.

  12. Development of a dose-controlled multiculture cell exposure chamber for efficient delivery of airborne and engineered nanoparticles

    Science.gov (United States)

    Asimakopoulou, Akrivi; Daskalos, Emmanouil; Lewinski, Nastassja; Riediker, Michael; Papaioannou, Eleni; Konstandopoulos, Athanasios G.

    2013-04-01

    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.

  13. Informing resource-poor populations and the delivery of entitled health and social services in rural India: a cluster randomized controlled trial.

    Science.gov (United States)

    Pandey, Priyanka; Sehgal, Ashwini R; Riboud, Michelle; Levine, David; Goyal, Madhav

    2007-10-24

    A lack of awareness about entitled health and social services may contribute to poor delivery of such services in developing countries, especially among individuals of low socioeconomic status. To determine the impact of informing resource-poor rural populations about entitled services. Community-based, cluster randomized controlled trial conducted from May 2004 to May 2005 in 105 randomly selected village clusters in Uttar Pradesh state in India. Households (548 intervention and 497 control) were selected by a systematic sampling design, including both low-caste and mid- to high-caste households. Four to 6 public meetings were held in each intervention village cluster to disseminate information on entitled health services, entitled education services, and village governance requirements. No intervention took place in control village clusters. Visits by nurse midwife; prenatal examinations, tetanus vaccinations, and prenatal supplements received by pregnant women; vaccinations received by infants; excess school fees charged; occurrence of village council meetings; and development work in villages. At baseline, there were no significant differences in self-reported delivery of health and social services. After 1 year, intervention villagers reported better delivery of several services compared with control villagers: in a multivariate analysis, 30% more prenatal examinations (95% confidence interval [CI], 17%-43%; P India about entitled services enhanced the delivery of health and social services among both low- and mid- to high-caste households. Interventions that emphasize educating resource-poor populations about entitled services may improve the delivery of such services. clinicaltrials.gov Identifier: NCT00421291.

  14. Patterned structures of in situ size controlled CdS nanocrystals in a polymer matrix under UV irradiation

    International Nuclear Information System (INIS)

    Fragouli, D; Pompa, P P; Caputo, G; Cingolani, R; Athanassiou, A; Resta, V; Laera, A M; Tapfer, L

    2009-01-01

    A method of in situ formation of patterns of size controlled CdS nanocrystals in a polymer matrix by pulsed UV irradiation is presented. The films consist of Cd thiolate precursors with different carbon chain lengths embedded in TOPAS polymer matrices. Under UV irradiation the precursors are photolyzed, driving to the formation of CdS nanocrystals in the quantum size regime, with size and concentration defined by the number of incident UV pulses, while the host polymer remains macroscopically/microscopically unaffected. The emission of the formed nanocomposite materials strongly depends on the dimensions of the CdS nanocrystals, thus, their growth at the different phases of the irradiation is monitored using spatially resolved photoluminescence by means of a confocal microscope. X-ray diffraction measurements verified the existence of the CdS nanocrystals, and defined their crystal structure for all the studied cases. The results are reinforced by transmission electron microscopy. It is proved that the selection of the precursor determines the efficiency of the procedure, and the quality of the formed nanocrystals. Moreover it is demonstrated that there is the possibility of laser induced formation of well-defined patterns of CdS nanocrystals, opening up new perspectives in the development of nanodevices.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Patterned structures of in situ size controlled CdS nanocrystals in a polymer matrix under UV irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Fragouli, D; Pompa, P P; Caputo, G; Cingolani, R; Athanassiou, A [NNL-National Nanotechnology Laboratory, INFM, CNR, Via Arnesano, 73100 Lecce (Italy); Resta, V; Laera, A M; Tapfer, L [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy)], E-mail: despina.fragouli@unile.it

    2009-04-15

    A method of in situ formation of patterns of size controlled CdS nanocrystals in a polymer matrix by pulsed UV irradiation is presented. The films consist of Cd thiolate precursors with different carbon chain lengths embedded in TOPAS polymer matrices. Under UV irradiation the precursors are photolyzed, driving to the formation of CdS nanocrystals in the quantum size regime, with size and concentration defined by the number of incident UV pulses, while the host polymer remains macroscopically/microscopically unaffected. The emission of the formed nanocomposite materials strongly depends on the dimensions of the CdS nanocrystals, thus, their growth at the different phases of the irradiation is monitored using spatially resolved photoluminescence by means of a confocal microscope. X-ray diffraction measurements verified the existence of the CdS nanocrystals, and defined their crystal structure for all the studied cases. The results are reinforced by transmission electron microscopy. It is proved that the selection of the precursor determines the efficiency of the procedure, and the quality of the formed nanocrystals. Moreover it is demonstrated that there is the possibility of laser induced formation of well-defined patterns of CdS nanocrystals, opening up new perspectives in the development of nanodevices.

  20. 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...... the performance of the proposed mechanism against traditional congestion control with a simulation study. The results show that the proposed approach can improve the overall performance both by increasing the throughput over the wireless and improving the video quality in terms of peak signal-to-noise ratio (PSNR...

  1. 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.

  2. 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.

  3. Aminopropyl groups of the functionalized Mobil Crystalline Material 41 as a carrier for controlled diclofenac sodium and piroxicam delivery.

    Science.gov (United States)

    Khodaverdi, Elham; Ahmadi, Mina; Kamali, Hossein; Hadizadeh, Farzin

    2017-01-01

    Synthetic Mobil Crystalline Material 41 (MCM-41) as a mesoporous material and functionalized MCM-41 using aminopropyl groups were studied in order to investigate their ability to encapsulate and to control the release of diclofenac sodium and piroxicam. MCM-41 was synthesized through sol-gel procedure and functionalized with aminopropyl groups. The physicochemical properties of MCM-41 were studied through particle size analysis, infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and carbon-hydrogen-nitrogen analysis. Diclofenac sodium and piroxicam were loaded into the MCM-41 matrix using the filtration and solvent evaporation methods. The drug-loading capacity was determined by ultraviolet, Fourier transform infrared, X-ray diffraction, and Brunauer-Emmett-Teller analysis. According to the results for pure drug release, >57% was released in the 1 st h, but when these drugs were loaded into pure Mobil Crystalline Material 41 (MCM-41) and functionalized MCM-41, the release into the simulated gastrointestinal medium was less, continuous, and slower. The release of piroxicam from functionalized MCM-41 was slower than that from MCM-41 in the simulated intestinal medium because of the formation of electrostatic bonds between piroxicam and the aminopropyl groups of the functionalized MCM-41. However, in the case of diclofenac sodium, there was no significant difference between pure MCM-41 and functionalized MCM-41. The difference between piroxicam and diclofenac sodium was due to the high solubility of diclofenac sodium in the intestinal medium (pH 6.8), which caused more rapid release from the matrixes than for piroxicam. Our findings indicate that, after functionalization of MCM-41, it could offer a good means of delivering controlled diclofenac sodium and piroxicam.

  4. 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.

  5. 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 ...

  6. 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…

  7. Development of a desiccated cadaver delivery system to apply entomopathogenic nematodes for control of soil pests

    Science.gov (United States)

    Pentomopathogenic nematodes may be more capable of controlling soil pests when they are harbored by desiccated cadavers. A small-scale system was developed from a modified crop seed planter to effectively deliver desiccated nematode-infected cadavers into the soil. The system mainly consists of a me...

  8. Title IV Quality Control Project, Stage II. Management Option II: Delivery System Quality Improvements.

    Science.gov (United States)

    Advanced Technology, Inc., Reston, VA.

    Stage Two of the Title IV Quality Control Project is an integrated study of quality in five related Federal financial aid programs for postsecondary students. Section 1 of the paper establishes a framework for defining quality improvements, in order to identify the types of changes that would tend to improve quality across all facets of the…

  9. 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.

  10. A novel approach to the use of subgingival controlled-release chlorhexidine delivery in chronic periodontitis: a randomized clinical trial.

    Science.gov (United States)

    Gonzales, Jose R; Harnack, Lutz; Schmitt-Corsitto, Gabriella; Boedeker, Rolf H; Chakraborty, Trinad; Domann, Eugen; Meyle, Joerg

    2011-08-01

    We aimed to analyze clinical, microbiologic, and serologic effects of chlorhexidine (CHX) chips used as a subgingival controlled-release delivery device before and immediately after scaling and root planing (SRP). Twenty-four patients presenting with ≥12 teeth with probing depth (PD) ≥5 mm and bleeding on probing were assigned in test or control groups. After prophylaxis, CHX chips (test) or placebo chips (control) were placed in pockets with PD ≥5 mm. Ten days later, SRP was performed in all teeth with PD ≥4 mm in a single appointment. Immediately after SRP, new chips were inserted in all pockets with PD ≥5 mm. Parameters were assessed at baseline; beginning of SRP; and 1, 3, and 6 months after treatment. Subgingival samples were obtained at baseline; beginning of SRP; and at 1 month after treatment. Periodontal pathogens Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, Tannerella forsythia, and Treponema denticola were analyzed. Serum levels of high sensitive C-reactive and lipopolysaccharide-binding proteins were measured. The changes of the parameters between and within the groups were tested by Mann-Whitney U test (P periodontitis.

  11. Magnetic high throughput screening system for the development of nano-sized molecularly imprinted polymers for controlled delivery of curcumin.

    Science.gov (United States)

    Piletska, Elena V; Abd, Bashar H; Krakowiak, Agata S; Parmar, Anitha; Pink, Demi L; Wall, Katie S; Wharton, Luke; Moczko, Ewa; Whitcombe, Michael J; Karim, Kal; Piletsky, Sergey A

    2015-05-07

    Curcumin is a versatile anti-inflammatory and anti-cancer agent known for its low bioavailability, which could be improved by developing materials capable of binding and releasing drug in a controlled fashion. The present study describes the preparation of magnetic nano-sized Molecularly Imprinted Polymers (nanoMIPs) for the controlled delivery of curcumin and their high throughput characterisation using microtitre plates modified with magnetic inserts. NanoMIPs were synthesised using functional monomers chosen with the aid of molecular modelling. The rate of release of curcumin from five polymers was studied under aqueous conditions and was found to correlate well with the binding energies obtained computationally. The presence of specific monomers was shown to be significant in ensuring effective binding of curcumin and to the rate of release obtained. Characterisation of the polymer particles was carried out using dynamic light scattering (DLS) technique and scanning electron microscopy (SEM) in order to establish the relationship between irradiation time and particle size. The protocols optimised during this study could be used as a blueprint for the development of nanoMIPs capable of the controlled release of potentially any compound of interest.

  12. Analysis of preterm deliveries below 35 weeks' gestation in a tertiary referral hospital in the UK. A case-control survey

    Directory of Open Access Journals (Sweden)

    Sellers Susan M

    2010-04-01

    Full Text Available Abstract Background Preterm birth remains a major public health problem and its incidence worldwide is increasing. Epidemiological risk factors have been investigated in the past, but there is a need for a better understanding of the causes of preterm birth in well defined obstetric populations in tertiary referral centres; it is important to repeat surveillance and identify possible changes in clinical and socioeconomic factors associated with preterm delivery. The aim of this study was to identify current risk factors associated with preterm delivery and highlight areas for further research. Findings We studied women with singleton deliveries at St Michael's Hospital, Bristol during 2002 and 2003. 274 deliveries between 23-35 weeks' gestation (preterm group, were compared to 559 randomly selected control deliveries at term (37-42 weeks using standard statistical procedures. Both groups were >80% Caucasian. Previous preterm deliveries, high maternal age (> 39 years, socioeconomic problems, smoking during pregnancy, hypertension, psychiatric disorders and uterine abnormalities were significantly associated with preterm deliveries. Both lean and obese mothers were more common in the preterm group. Women with depression/psychiatric disease were significantly more likely to have social problems, to have smoked during pregnancy and to have had previous preterm deliveries; when adjustments for these three factors were made the relationship between psychiatric disease and pregnancy outcome was no longer significant. 53% of preterm deliveries were spontaneous, and were strongly associated with episodes of threatened preterm labour. Medically indicated preterm deliveries were associated with hypertension and fetal growth restriction. Preterm premature rupture of the membranes, vaginal bleeding, anaemia and oligohydramnios were significantly increased in both spontaneous and indicated preterm deliveries compared to term controls. Conclusions More than 50

  13. 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.

  14. Admission and Preventive Load Control for Delivery of Multicast and Broadcast Services via S-UMTS

    Science.gov (United States)

    Angelou, E.; Koutsokeras, N.; Andrikopoulos, I.; Mertzanis, I.; Karaliopoulos, M.; Henrio, P.

    2003-07-01

    An Admission Control strategy is proposed for unidirectional satellite systems delivering multicast and broadcast services to mobile users. In such systems, both the radio interface and the targeted services impose particular requirements on the RRM task. We briefly discuss the RRM requirements that stem from the services point of view and from the features of the SATIN access scheme that differentiate it from the conventional T-UMTS radio interface. The main functional entities of RRM and the alternative modes of operation are outlined and the proposed Admission Control algorithm is described in detail. The results from the simulation study that demonstrate its performance for a number of different scenarios are finally presented and conclusions derived.

  15. A comparative histological study of alginate beads as a promising controlled release delivery for mefenamic acid.

    Science.gov (United States)

    Sevgi, Ferhan; Kaynarsoy, Buket; Ozyazici, Mine; Pekcetin, Cetin; Ozyurt, Dogan

    2008-01-01

    The new mefenamic acid-alginate bead formulation prepared by ionotropic gelation method using 3 x 2(2) factorial design has shown adequate controlled release properties in vitro. In the present study, the irritation effects of mefenamic acid (MA), a prominent non-steroidal anti-inflammatory (NSAI) drug, were evaluated on rat gastric and duodenal mucosa when suspended in 0.5% (w/v) sodiumcarboxymethylcellulose (NaCMC) solution and loaded in alginate beads. Wistar albino rats weighing 200 +/- 50 g were used during in vivo animal studies. In this work, biodegradable controlled release MA beads and free MA were evaluated according to the degree of gastric or duodenal damage following oral administration in rats. The gastric and duodenal mucosa was examined for any haemorrhagic changes. Formulation code A10 showing both Case II transport and zero order drug release and t(50) % value of 5.22 h was chosen for in vivo animal studies. For in vivo trials, free MA (100 mgkg(-1)), blank and MA (100 mgkg(-1)) loaded alginate beads (formulation code A10) were suspended in 0.5% (w/v) NaCMC solution and each group was given to six rats orally by gavage. NaCMC solution was used as a control in experimental studies. In vivo data showed that the administration of MA in alginate beads prevented the gastric lesions.

  16. 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.

  17. Parallel Programming Application to Matrix Algebra in the Spectral Metho