Comparison of the Amount of Fluoride Release from Nanofilled Resin Modified Glass Ionomer Conventional and Resin Modified Glass Ionomer Cements

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Sumitha Upadhyay

2013-01-01

Full Text Available Objective: To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements.Materials and Methods: Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37◦C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance using SPSS 11.0. The significance level was set at p< 0.05.Results: The release of fluoride was highest on day 1 and there was a sudden fall on day 2 in all three groups. Initially fluoride release from conven-tional glass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 daysConclusion: The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

Effective control of modified palygorskite to NH4+-N release from sediment.

Science.gov (United States)

Chen, Lei; Zheng, Tianyuan; Zhang, Junjie; Liu, Jie; Zheng, Xilai

2014-01-01

Sediment capping is an in situ treatment technology that can effectively restrain nutrient and pollutant release from the sediment in lakes and reservoirs. Research on sediment capping has focused on the search for effective, non-polluting and affordable capping materials. The efficiency and mechanism of sediment capping with modified palygorskite in preventing sediment ammonia nitrogen (NH4+-N) release to surface water were investigated through a series of batch and sediment capping experiments. Purified palygorskite and different types of modified palygorskite (i.e. heated, acid-modified and NaCI-modified palygorskite) were used in this investigation. Factors affecting control efficiency, including the temperature, thickness and grain size of the capping layer, were also analysed. The batch tests showed that the adsorption of NH4+-N on modified palygorskite achieved an equilibration in the initial 45 min, and the adsorption isotherm followed the Freundlich equation. Sediment capping experiments showed that compared with non-capped condition, covering the sediment with modified palygorskite and sand both inhibited NH4+-N release to the overlying water. Given its excellent chemical stability and strong adsorption, heated palygorskite, which has a NH4+-N release inhibition ratio of 41.3%, is a more effective sediment capping material compared with sand. The controlling effectiveness of the modified palygorskite increases with thicker capping layer, lower temperature and smaller grain size of the capping material.

Sustained release nimesulide microparticles: evaluation of release modifying property of ethy

International Nuclear Information System (INIS)

Khan, S.A.; Ahmed, M.; Nisar-ur-Rehman; Madni, A.U.; Aamir, M.N.; Murtaza, G.

2011-01-01

Microencapsulated controlled-release preparations of nimesulide were formulated. Microparticles were prepared by modified phase separation (non-solvent addition) technique using different ratios of ethylcellulose. The microparticles (M/sub 1/, M/sub 2/, and M/sub 3/) were yellow, free flowing and spherical in shape with the particle size varying from 93.62 +- 14.15 to 104.19 +- 18.15 mu m. The t/sub 60%/of nimesulide release from microparticles was found to be 3 +- 0.6, 5 +- 0.6 and 8 +- 0.8 h for formulations M/sub 1/, M/sub 2/, and M/sub 3/, respectively. FT-IR, XRD, and thermal analysis were done which showed that there is no interaction between the polymer and drug. The mechanism of drug release from nimesulide microparticles was studied by using Higuchi and Korsmeyer-Peppas models. The value of coefficient of determination (R/sup 2/) for M/sub 1/, M/sub 2/, and M/sub 3/ indicates anomalous and case-II transport release mechanism. The dissolution data of designed system verified its ability to maintain plasma concentration without the need of frequent dosing. The Nimesulide microparticles prolonged drug release for 12 hours or longer. Based on the results of release studies, M/sub 3/ was opted as a suitable microparticulate formulation allowing the controlled release of nimesulide over a prolonged period of time. Moreover, its encapsulation efficiency was also comparable to the other two formulations (M/sub 1/ and M/sub 2/). In conclusion, the influence of polymer concentration should be considered during formulation development. (author)

Artificial Neural Networks in Evaluation and Optimization of Modified Release Solid Dosage Forms

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Zorica Djurić

2012-10-01

Full Text Available Implementation of the Quality by Design (QbD approach in pharmaceutical development has compelled researchers in the pharmaceutical industry to employ Design of Experiments (DoE as a statistical tool, in product development. Among all DoE techniques, response surface methodology (RSM is the one most frequently used. Progress of computer science has had an impact on pharmaceutical development as well. Simultaneous with the implementation of statistical methods, machine learning tools took an important place in drug formulation. Twenty years ago, the first papers describing application of artificial neural networks in optimization of modified release products appeared. Since then, a lot of work has been done towards implementation of new techniques, especially Artificial Neural Networks (ANN in modeling of production, drug release and drug stability of modified release solid dosage forms. The aim of this paper is to review artificial neural networks in evaluation and optimization of modified release solid dosage forms.

Drug delivery systems with modified release for systemic and biophase bioavailability.

Science.gov (United States)

Leucuta, Sorin E

2012-11-01

This review describes the most important new generations of pharmaceutical systems: medicines with extended release, controlled release pharmaceutical systems, pharmaceutical systems for the targeted delivery of drug substances. The latest advances and approaches for delivering small molecular weight drugs and other biologically active agents such as proteins and nucleic acids require novel delivery technologies, the success of a drug being many times dependent on the delivery method. All these dosage forms are qualitatively superior to medicines with immediate release, in that they ensure optimal drug concentrations depending on specific demands of different disease particularities of the body. Drug delivery of these pharmaceutical formulations has the benefit of improving product efficacy and safety, as well as patient convenience and compliance. This paper describes the biopharmaceutical, pharmacokinetic, pharmacologic and technological principles in the design of drug delivery systems with modified release as well as the formulation criteria of prolonged and controlled release drug delivery systems. The paper presents pharmaceutical prolonged and controlled release dosage forms intended for different routes of administration: oral, ocular, transdermal, parenteral, pulmonary, mucoadhesive, but also orally fast dissolving tablets, gastroretentive drug delivery systems, colon-specific drug delivery systems, pulsatile drug delivery systems and carrier or ligand mediated transport for site specific or receptor drug targeting. Specific technologies are given on the dosage forms with modified release as well as examples of marketed products, and current research in these areas.

Development of New Gonadotropin-Releasing Hormone-Modified Dendrimer Platforms with Direct Antiproliferative and Gonadotropin Releasing Activity.

Science.gov (United States)

Varamini, Pegah; Rafiee, Amirreza; Giddam, Ashwini Kumar; Mansfeld, Friederike M; Steyn, Frederik; Toth, Istvan

2017-10-26

Gonadotropin-releasing hormone (GnRH) agonists (e.g., triptorelin) are used for androgen suppression therapy. They possess improved stability as compared to the natural GnRH, yet they suffer from a poor pharmacokinetic profile. To address this, we used a GnRH peptide-modified dendrimer platform with and without lipidation strategy. Dendrimers were synthesized on a polylysine core and bore either native GnRH (1, 2, and 5) or lipid-modified GnRH (3 and 4). Compound 3, which bore a lipidic moiety in a branched tetramer structure, showed approximately 10-fold higher permeability and metabolic stability and 39 times higher antitumor activity against hormone-resistant prostate cancer cells (DU145) relative to triptorelin. In gonadotropin-release experiments, dendrimer 3 was shown to be the most potent construct. Dendrimer 3 showed similar luteinizing hormone (LH)-release activity to triptorelin in mice. Our findings indicate that dendrimer 3 is a promising analog with higher potency for the treatment of hormone-resistant prostate cancer than the currently available GnRH agonists.

PNIPAAM modified mesoporous hydroxyapatite for sustained osteogenic drug release and promoting cell attachment

Energy Technology Data Exchange (ETDEWEB)

Wu, Tao [The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079 (China); Tan, Lei [Key Laboratory of Biomedical Polymers of Ministry of Education, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Cheng, Ning; Yan, Qi; Zhang, Yu-Feng [The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079 (China); Liu, Chuan-Jun, E-mail: cjliu@whu.edu.cn [Key Laboratory of Biomedical Polymers of Ministry of Education, College of Chemistry and Molecular Science, Wuhan University, Wuhan 430072 (China); Shi, Bin, E-mail: shibin_dentist@126.com [The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, 237 Luoyu Road, Wuhan 430079 (China)

2016-05-01

This work presented a sustained release system of simvastatin (SIM) based on the mesoporous hydroxyapatite (MHA) capped with poly(N-isopropylacrylamide) (PNIPAAM). The MHA was prepared by using cetyltrimethylammonium bromide (CTAB) as a template and the modified PNIPAAM layer on the surface of MHA was fabricated through surface-initiated atom transfer radical polymerization (SI-ATRP). The SIM loaded MHA-PNIPAAM showed a sustained release of SIM at 37 °C over 16 days. The bone marrow mesenchymal stem cell (BMSC) proliferation was assessed by cell counting kit-8 (CCK-8) assay, and the osteogenic differentiation was evaluated by alkaline phosphatase (ALP) activity and Alizarin Red staining. The release profile showed that the release of SIM from MHA-SIM-PNIPAAM lasted 16 days and the cumulative amount of released SIM was almost seven-fold than MHA-SIM. Besides, SIM loaded MHA-PNIPAAM exhibited better performance on cell proliferation, ALP activity, and calcium deposition than pure MHA due to the sustained release of SIM. The quantity of ALP in MHA-SIM-PNIPAAM group was more than two fold than pure MHA group at 7 days. Compared to pure MHA, better BMSC attachment on PNIPAAM modified MHA was observed using fluorescent microscopy, indicating the better biocompatibility of MHA-PNIPAAM. - Highlights: • PNIPAAM modified mesoporous hydroxyapatite (MHA) was fabricated by SI-ATRP. • SIM loaded MHA-PNIPAAM continually released SIM in effect concentration for 16 days. • MHA-SIM-PNIPAAM behaved well on cell proliferation, ALP activity and calcium deposition.

Solubility and release of fenbufen intercalated in Mg, Al and Mg, Al, Fe layered double hydroxides (LDH): The effect of Eudragit S 100 covering

International Nuclear Information System (INIS)

Arco, M. del; Fernandez, A.; Martin, C.; Rives, V.

2010-01-01

Following different preparation routes, fenbufen has been intercalated in the interlayer space of layered double hydroxides with Mg 2+ and Al 3+ or Mg 2+ , Al 3+ and Fe 3+ in the layers. Well crystallized samples were obtained in most of the cases (intercalation was not observed by reconstruction of the MgAlFe matrix), with layer heights ranging between 16.1 and 18.8 A. The presence of the LDH increases the solubility of fenbufen, especially when used as a matrix. The dissolution rate of the drug decreases when the drug is intercalated, and is even lower in those systems containing iron; release takes place through ionic exchange with phosphate anions from the solution. Preparation of microspheres with Eudragit S 100 leads to solids with an homogeneous, smooth surface with efficient covering of the LDH surface, as drug release was not observed at pH lower than 7. - Graphical abstract: LDHs containing Mg, Al, Fe increase fenbufen solubility, release takes place through ionic exchange with phosphate anions from the medium. Spherical solids with homogeneous, smooth surface are formed when using Eudragit S 100, efficiently covering the LDH surface. Display Omitted

Comparing the Electrochemical Performance of LiFePO4/C Modified by Mg Doping and MgO Coating

Directory of Open Access Journals (Sweden)

Jianjun Song

2013-01-01

Full Text Available Supervalent cation doping and metal oxide coating are the most efficacious and popular methods to optimize the property of LiFePO4 lithium battery material. Mg-doped and MgO-coated LiFePO4/C were synthesized to analyze their individual influence on the electrochemical performance of active material. The specific capacity and rate capability of LiFePO4/C are improved by both MgO coating and Mg doping, especially the Mg-doped sample—Li0.985Mg0.015FePO4/C, whose discharge capacity is up to 163 mAh g−1, 145.5 mAh g−1, 128.3 mAh g−1, and 103.7 mAh g−1 at 1 C, 2 C, 5 C, and 10 C, respectively. The cyclic life of electrode is obviously increased by MgO surface modification, and the discharge capacity retention rate of sample LiFePO4/C-MgO2.5 is up to 104.2% after 100 cycles. Comparing samples modified by these two methods, Mg doping is more prominent on prompting the capacity and rate capability of LiFePO4, while MgO coating is superior in terms of improving cyclic performance.

A novel fluoride anion modified gelatin nanogel system for ultrasound-triggered drug release.

Science.gov (United States)

Wu, Daocheng; Wan, Mingxi

2008-01-01

Controlled drug release, especially tumor-targeted drug release, remains a great challenge. Here, we prepare a novel fluoride anion-modified gelatin nanogel system and investigate its characteristics of ultrasound-triggered drug release. Adriamycin gelatin nanogel modified with fluoride anion (ADM-GNMF) was prepared by a modified co-precipitation method with fluoride anion and sodium sulfate. The loading and encapsulation efficiency of the anti-neoplastic agent adriamycin (ADM) were measured by high performance liquid chromatography (HPLC). The size and shape of ADM-GNMF were determined by electron microscopy and photo-correlation spectroscopy. The size distribution and drug release efficiency of ADM-GNMF, before and after sonication, were measured by two designed measuring devices that consisted of either a submicron particle size analyzer and an ultrasound generator as well as an ultrasound generator, automatic sampler, and HPLC. The ADM-GNMF was stable in solution with an average diameter of 46+/-12 nm; the encapsulation and loading efficiency of adriamycin were 87.2% and 6.38%, respectively. The ultrasound-triggered drug release and size change were most efficient at a frequency of 20 kHz, power density of 0.4w/cm2, and a 1~2 min duration. Under this ultrasound-triggered condition, 51.5% of drug in ADM-GNMF was released within 1~2 min, while the size of ADM-GNMF changed from 46 +/- 12 nm to 1212 +/- 35 nm within 1~2 min of sonication and restored to its previous size in 2~3 min after the ultrasound stopped. In contrast, 8.2% of drug in ADM-GNMF was released within 2~3 min without sonication, and only negligible size changes were found. The ADM-GNMF system efficiently released the encompassed drug in response to ultrasound, offering a novel and promising controlled drug release system for targeted therapy for cancer or other diseases.

Modified gum Arabic hydrogels as matrices for controlled release of curcumin supramolecular complexes

International Nuclear Information System (INIS)

Gerola, Adriana P.; Silva, Danielle C.; Rubira, Adley F.; Muniz, Edvani C.

2015-01-01

Modified gum Arabic (GA) hydrogels show a pH-responsive behavior making them excellent matrices to be used for oral administration of drugs. Our goal is to study the behavior of those matrices in simulated gastric and intestinal fluids. In this work we will present how the methacrylation degree of GA, by using glycidyl methacrylate, can affect the properties of these hydrogels for controlled release. The drug used in this work is the curcumin (Cur). Cur is associated with numerous pharmacological activities, but their application is limited by the low water solubility. We will present some studies involving the formation of host-guest complexes between Cur and natural cyclodextrins. Both modified GA and hydrogels were characterized by different techniques. The kinetics release of Cur complex-containing modified GA hydrogels was studied to have an insight on the release mechanism and rate constants. Toxicity studies on undifferentiated and differentiated Caco-2 were also carried out. (author)

Deliberate release of genetically modified plants into the environment in Slovenia

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Zlata LUTHAR

2015-11-01

Full Text Available Deliberate release of genetically modified higher plants (GMHPs into the environment in Slovenia is regulated by the Law on the Management of Genetically Modified Organisms (ZRGSO Ur. l. RS 23/2005 and 21/2010, III chapter. For each deliberate release of GMPs into the environment a license issued by the Ministry of Environment and Spatial Planning (MESP must be acquired. The application or notification should contain a very accurate and complex description of the GMP, of the field where it will be released and of wider surroundings or environment. The application consists of Annex 2 with accessories: 1. Part A (technical data for the authorization of deliberate GMP release into the environment; 2. Part B (environmental risk assessment; 3. Application summary in Slovenian and English language for the release of GMP into environment, which is transmitted to Brussels by MESP; 4. Extract from the Land Cadastre of the field to which the GMP will be released. The release procedure runs (till here under the above mentioned Law, which has been in place for several years and which clearly defines that it is possible to release GMP in Slovenia. In the case of GM rice in 2011, the law applied till the site selection of the experiment. Here, the law was not sufficiently taken into account. It was prevailed by the regulation of Farmland and Forest Fund of the Republic of Slovenia and municipal decision, which was stronger than the national law and prevented the cultivation of GM rice in an area that is legally suitable for release of GMO into the environment. Rice is not grown in Slovenia and does not have wild ancestors or close relatives with whom it might mate. Nearest area of cultivation is in neighboring Italy, which is from potentially selected location in Slovenia more than 70 km away.

The stress response to surgery: release mechanisms and the modifying effect of pain relief

DEFF Research Database (Denmark)

Kehlet, H

1989-01-01

This short review updates information on the release mechanisms of the systemic response to surgical injury and the modifying effect of pain relief. Initiation of the response is primarily due to afferent nerve impulses combined with release of humoral substances (such as prostaglandins, kinins...... in releasing the classical endocrine catabolic response, while humoral factors are important for the hyperthermic response, changes in coagulation and fibrinolysis immunofunction, and capillary permeability. The modifying effect of pain relief on the surgical stress response is dependent upon the technique...... on the stress response. In summary, pain alleviation itself may not necessarily lead to an important modification of the stress response, and a combined approach with inhibition of the neural and humoral release mechanisms is necessary for a pronounced inhibition or prevention of the response to surgical injury....

Aminobenzoate modified MgAl hydrotalcites as a novel smart additive of reinforced concrete for anticorrosion applications

NARCIS (Netherlands)

Yang, Z.; Fischer, H.R.; Cerezo, J.; Mol, J.M.C.; Polder, R.B.

2013-01-01

A carbonate form of MgAl hydrotalcite, Mg(2)Al-CO3 and its p-aminobenzoate (pAB) modified derivative, Mg(2)Al-pAB, were synthesized and characterized by means of XRD, FT-IR and TG/DSC. The anticorrosion behavior of Mg(2)Al-pAB was evaluated based on open circuit potential (OCP) of carbon steel in

Preparation and characterization of Ti-doped MgO nanopowders by a modified coprecipitation method

International Nuclear Information System (INIS)

Wang Wei; Qiao Xueliang; Chen Jianguo; Tan Fatang

2008-01-01

Ti-doped MgO nanopowders were prepared via a chemical coprecipitation method using acetic acid as a modifier in the presence of the surfactant polyethylene glycol (PEG 400). The as-obtained products were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), differential thermal analysis (DTA) and transmission electron microscopy (TEM). The results show that titanium atoms have been successfully incorporated into the crystal lattice of MgO with periclase structure. The modifier, acetic acid, can significantly reduce the particle size, and improve size distribution and dispersion of nanoparticles. In addition, the effect of doped titanium on the structure and morphology of magnesium oxide was also investigated

Biocompatible Silver Nanoparticle-Modified Natural Diatomite with Anti-Infective Property

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Haolin Sun

2018-01-01

Full Text Available Nanosilver as an alternative antibacterial agent of antibiotics has been researched for possible applications in various orthopedic implants. However, it is imperative to achieve controllable release of Ag+ to reduce its cytotoxic effect on normal tissue. Here, a nanosilver release system that has potential to be used in anti-infective bone cement was reported. Nanosilver modified diatomite was developed through the reaction of Tollens’ reagent to improve the antibacterial effect and natural diatomite was used as the carrier of Ag+ ions for controlled release. Cytotoxicity and the antibacterial activities of the nanosilver release system were characterized. After 3 days, the NIH3T3 cells cultured in the extract of nanosilver modified diatomite with an initial concentration of 0.5 mg/ml showed better cell viability than cells cultured in α-MEM. The density of MC3T3-E1 cells cultured in the extract of nanosilver modified diatomite at the same concentration did not differ significantly from the density of cells cultured in α-MEM. The nanosilver modified diatomite exhibited antibacterial effect against E. coli and S. aureus when the concentration was higher than 0.5 mg/ml. With appropriate selection of Ag+ concentration, the nanosilver modified diatomite is promising for improving the antibacterial effect while not affecting the biocompatibility of reinforced calcium phosphate bone cement.

Development of modified release diltiazem HCl tablets using composite index to identify optimal formulation.

Science.gov (United States)

Gohel, M C; Patel, M M; Amin, A F

2003-05-01

This article reports the preparation of tartaric acid treated ispaghula husk powder for the development of modified release tablets of diltiazem HCl by adopting direct compression technique and a 32 full factorial design. The modified ispaghula husk powder showed superior swelling and gelling as compared to untreated powder. Addition of compaction augmenting agent such as dicalcium phosphate was found to be essential for obtaining tablets with adequate crushing strength. In order to improve the crushing strength of diltiazem HCl tablets, to modulate drug release pattern, and to obtain similarity of dissolution profiles in distilled water and simulated gastric fluid (pH 1.2), modified guar gum was used along with modified ispaghula husk powder and tartaric acid. A novel composite index, which considers a positive or a negative deviation from an ideal value, was calculated considering percentage drug release in 60, 300, and 540 min as dependent variables for the selection of a most appropriate batch. Polynomial equation and contour plots are presented. The concept of similarity factor (f2) was used to prove similarity of dissolution in water and simulated gastric fluid (pH 1.2).

Degradation testing of Mg alloys in Dulbecco's modified eagle medium: Influence of medium sterilization.

Science.gov (United States)

Marco, Iñigo; Feyerabend, Frank; Willumeit-Römer, Regine; Van der Biest, Omer

2016-05-01

This work studies the in vitro degradation of Mg alloys for bioabsorbable implant applications under near physiological conditions. For this purpose, the degradation behaviour of Mg alloys in Dulbecco's modified eagle medium (DMEM) which is a commonly used cell culture medium is analysed. Unfortunately, DMEM can be contaminated by microorganisms, acidifying the medium and accelerating the Mg degradation process by dissolution of protective degradation layers, such as (Mgx,Cay)(PO4)z. In this paper the influence of sterilization by applying UV-C radiation and antibiotics (penicillin/streptomycin) is analysed with two implant material candidates: Mg-Gd and Mg-Ag alloys; and pure magnesium as well as Mg-4Y-3RE as a reference. Copyright © 2016 Elsevier B.V. All rights reserved.

MgO Nanoparticle Modified Anode for Highly Efficient SnO2-Based Planar Perovskite Solar Cells.

Science.gov (United States)

Ma, Junjie; Yang, Guang; Qin, Minchao; Zheng, Xiaolu; Lei, Hongwei; Chen, Cong; Chen, Zhiliang; Guo, Yaxiong; Han, Hongwei; Zhao, Xingzhong; Fang, Guojia

2017-09-01

Reducing the energy loss and retarding the carrier recombination at the interface are crucial to improve the performance of the perovskite solar cell (PSCs). However, little is known about the recombination mechanism at the interface of anode and SnO 2 electron transfer layer (ETL). In this work, an ultrathin wide bandgap dielectric MgO nanolayer is incorporated between SnO 2 :F (FTO) electrode and SnO 2 ETL of planar PSCs, realizing enhanced electron transporting and hole blocking properties. With the use of this electrode modifier, a power conversion efficiency of 18.23% is demonstrated, an 11% increment compared with that without MgO modifier. These improvements are attributed to the better properties of MgO-modified FTO/SnO 2 as compared to FTO/SnO 2 , such as smoother surface, less FTO surface defects due to MgO passivation, and suppressed electron-hole recombinations. Also, MgO nanolayer with lower valance band minimum level played a better role in hole blocking. When FTO is replaced with Sn-doped In 2 O 3 (ITO), a higher power conversion efficiency of 18.82% is demonstrated. As a result, the device with the MgO hole-blocking layer exhibits a remarkable improvement of all J-V parameters. This work presents a new direction to improve the performance of the PSCs based on SnO 2 ETL by transparent conductive electrode surface modification.

An investigation of effects of modification processes on physical properties and mechanism of drug release for sustaining drug release from modified rice

Energy Technology Data Exchange (ETDEWEB)

Ngo, Vuong Duy; Luu, Thinh Duc; Van Vo, Toi [Pharmaceutical Engineering Laboratory, Biomedical Engineering Department, International University, Vietnam National University, Ho Chi Minh City (Viet Nam); Tran, Van-Thanh [Faculty of Pharmacy, University of Medicine and Pharmacy, Ho Chi Minh City (Viet Nam); Duan, Wei [School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria (Australia); Tran, Phuong Ha-Lien, E-mail: phuong.tran1@deakin.edu.au [School of Medicine, Deakin University, Pigdons Road, Waurn Ponds, Victoria (Australia); Tran, Thao Truong-Dinh, E-mail: ttdthao@hcmiu.edu.vn [Pharmaceutical Engineering Laboratory, Biomedical Engineering Department, International University, Vietnam National University, Ho Chi Minh City (Viet Nam)

2016-10-01

The aim of this study was to investigate the effect of modification processes on physical properties and explain the mechanism of sustained drug release from modified rice (MR). Various types of Vietnamese rice were introduced in the study as the matrices of sustained release dosage form. Rice was thermally modified in water for a determined temperature at different times with a simple process. Then tablets containing MR and isradipine, the model drug, were prepared to investigate the capability of sustained drug release. Scanning electron microscopy (SEM) was used to determine different morphologies between MR formulations. Flow property of MR was analyzed by Hausner ratio and Carr's indices. The dissolution rate and swelling/erosion behaviors of tablets were evaluated at pH 1.2 and pH 6.8 at 37 ± 0.5 °C. The matrix tablet containing MR showed a sustained release as compared to the control. The SEM analyses and swelling/erosion studies indicated that the morphology as well as swelling/erosion rate of MR were modulated by modification time, drying method and incubation. It was found that the modification process was crucial because it could highly affect the granule morphologies and hence, leading to the change of flowability and swelling/erosion capacity for sustained release of drug. - Highlights: • Modification process affected granule morphologies and flowability of modified rice. • Modification process affected swelling/erosion capacity for drug sustained release. • Freeze-drying could decrease the erosion as well as increase the swelling rate.

An investigation of effects of modification processes on physical properties and mechanism of drug release for sustaining drug release from modified rice

International Nuclear Information System (INIS)

Ngo, Vuong Duy; Luu, Thinh Duc; Van Vo, Toi; Tran, Van-Thanh; Duan, Wei; Tran, Phuong Ha-Lien; Tran, Thao Truong-Dinh

2016-01-01

The aim of this study was to investigate the effect of modification processes on physical properties and explain the mechanism of sustained drug release from modified rice (MR). Various types of Vietnamese rice were introduced in the study as the matrices of sustained release dosage form. Rice was thermally modified in water for a determined temperature at different times with a simple process. Then tablets containing MR and isradipine, the model drug, were prepared to investigate the capability of sustained drug release. Scanning electron microscopy (SEM) was used to determine different morphologies between MR formulations. Flow property of MR was analyzed by Hausner ratio and Carr's indices. The dissolution rate and swelling/erosion behaviors of tablets were evaluated at pH 1.2 and pH 6.8 at 37 ± 0.5 °C. The matrix tablet containing MR showed a sustained release as compared to the control. The SEM analyses and swelling/erosion studies indicated that the morphology as well as swelling/erosion rate of MR were modulated by modification time, drying method and incubation. It was found that the modification process was crucial because it could highly affect the granule morphologies and hence, leading to the change of flowability and swelling/erosion capacity for sustained release of drug. - Highlights: • Modification process affected granule morphologies and flowability of modified rice. • Modification process affected swelling/erosion capacity for drug sustained release. • Freeze-drying could decrease the erosion as well as increase the swelling rate.

Release of nanoclay and surfactant from polymer-clay nanocomposites into a food simulant.

Science.gov (United States)

Xia, Yining; Rubino, Maria; Auras, Rafael

2014-12-02

Release assessment of organo-modified montmorillonite (O-MMT) nanoclay and the organo-modifiers (surfactants) was performed on two types of polymer–clay nanocomposites: polypropylene (PP) and polyamide 6 (PA6) with O-MMT. In accordance with ASTM D4754-11, nanocomposite films were exposed to ethanol as a fatty-food simulant at 70 °C. The release of O-MMT, with Si and Al used as the nanoclay markers, was evaluated by graphite furnace atomic absorption spectrometry. The nanoclay particles released in ethanol were visualized by transmission electron microscopy (TEM). More nanoclay particles were released from PP–clay films (0.15 mg L(–1)) than from PA6–clay films (0.10 mg L(–1)), possibly due to the lack of interaction between the nanoclay and PP as indicated by the structure and morphology in the TEM images. The surfactant release was quantified by a liquid chromatography tandem mass spectrometry (LC-MS/MS) method. A substantial amount of surfactant was released into ethanol (3.5 mg L(–1) from PP–clay films and 16.2 mg L(–1) from PA6–clay films), indicating changes in the nanoclay structure within the nanocomposite while it was exposed to ethanol. This research has provided information for the determination of exposure doses of nanoclay and surfactant in biosystems and the environment, which enabled the risk assessment.

Fluoride release and recharge behavior of a nano-filled resin-modified glass ionomer compared with that of other fluoride releasing materials.

Science.gov (United States)

Mitra, Sumita B; Oxman, Joe D; Falsafi, Afshin; Ton, Tiffany T

2011-12-01

To compare the long-term fluoride release kinetics of a novel nano-filled two-paste resin-modified glass-ionomer (RMGI), Ketac Nano (KN) with that of two powder-liquid resin-modified glass-ionomers, Fuji II LC (FLC) and Vitremer (VT) and one conventional glass-ionomer, Fuji IX (FIX). Fluoride release was measured in vitro using ion-selective electrodes. Kinetic analysis was done using regression analysis and compared with existing models for GIs and compomers. In a separate experiment the samples of KN and two conventional glass-ionomers, FIX and Ketac Molar (KM) were subjected to a treatment with external fluoride source (Oral-B Neutra-Foam) after 3 months of fluoride release and the recharge behavior studied for an additional 7-day period. The cumulative amount of fluoride released from KN, VT and FLC and the release profiles were statistically similar but greater than that for FIX at P coating of KN with its primer and of DY with its adhesive did not significantly alter the fluoride release behavior of the respective materials. The overall rate for KN was significantly higher than for the compomer DY. DY showed a linear rate of release vs. t and no burst effect as expected for compomers. The nanoionomer KN showed fluoride recharge behavior similar to the conventional glass ionomers FIX and KM. Thus, it was concluded that the new RMGI KN exhibits fluoride ion release behavior similar to typical conventional and RMGIs and that the primer does not impede the release of fluoride.

Spheroidization of primary Mg{sub 2}Si in Al-20Mg{sub 2}Si-4.5Cu alloy modified with Ca and Sb during T6 heat treatment process

Energy Technology Data Exchange (ETDEWEB)

Yu, Hong-Chen; Wang, Hui-Yuan, E-mail: wanghuiyuan@jlu.edu.cn; Chen, Lei; Zha, Min, E-mail: minzha@jlu.edu.cn; Wang, Cheng; Li, Chao; Jiang, Qi-Chuan

2017-02-08

The morphology evolution of primary Mg{sub 2}Si particles in a Al-20Mg{sub 2}Si-4.5Cu alloy both unmodified and modified with 0.5 wt% Ca-Sb prepared by hot-extrusion followed by T6 heat treatment was investigated in the present study. Interestingly, we found that the combination of hot-extrusion and T6 heat treatment was efficient in transforming truncated octahedral primary Mg{sub 2}Si into sphere in the modified alloy. In contrast, the primary Mg{sub 2}Si particles still kept dentritic in the unmodified alloy. It suggested that the formation of truncated octahedral primary Mg{sub 2}Si particles in as-cast state, the fragmentation of particles by hot-extrusion and the enhanced solid-state diffusion of Si and/or Mg atoms during heat treatment were responsible for the spheroidization of primary Mg{sub 2}Si. Moreover, the existence of fine (~10–20 µm) spherical primary Mg{sub 2}Si played an important role in strengthening the alloy, i.e., the ultimate tensile strength (UTS) increased from ~227 MPa in the unmodified alloy to ~303 MPa in the modified one. It is because the fine spherical primary Mg{sub 2}Si particles can provide a higher fracture stress and strength of the matrix/particle interface. Our study offered a simple methodology to prepare spherical primary Mg{sub 2}Si in an Al-high Mg{sub 2}Si alloy, which is beneficial to design novel light-weight Al-Mg-Si alloys with improved mechanical properties.

Development of modified-release tablets of zolpidem tartrate by biphasic quick/slow delivery system.

Science.gov (United States)

Mahapatra, Anjan Kumar; Sameeraja, N H; Murthy, P N

2015-06-01

Zolpidem tartrate is a non-benzodiazepine analogue of imidazopyridine of sedative and hypnotic category. It has a short half-life with usual dosage regimen being 5 mg, two times a day, or 10 mg, once daily. The duration of action is considered too short in certain circumstances. Thus, it is desirable to lengthen the duration of action. The formulation design was implemented by preparing extended-release tablets of zolpidem tartrate using the biphasic delivery system technology, where sodium starch glycolate acts as a superdisintegrant in immediate-release part and hydroxypropyl methyl cellulose as a release retarding agent in extended-release core. Tablets were prepared by direct compression. Both the core and the coat contained the drug. The pre-compression blends were evaluated for angle of repose, bulk density, and compressibility index. The tablets were evaluated for thickness, hardness, weight variation test, friability, and in vitro release studies. No interaction was observed between zolpidem tartrate and excipients from the Fourier transform infrared spectroscopy and differential scanning calorimetry analysis. The results of all the formulations prepared were compared with reference product Stilnoct®. Optimized formulations showed release patterns that match the United States Pharmacopeia (USP) guidelines for zolpidem tartrate extended-release tablets. The mechanism of drug release was studied using different mathematical models, and the optimized formulation has shown Fickian diffusion. Accelerated stability studies were performed on the optimized formulation.

Modified hMG stimulated: an effective option in endometrial preparation for frozen-thawed embryo transfer in patients with normal menstrual cycles.

Science.gov (United States)

Huang, Pinxiu; Wei, Lihong; Li, Xinlin; Lin, Zhong

2018-04-20

To evaluate the clinical efficacy of modified human menopausal gonadotropin (hMG) stimulated, hormone replacement therapy (HRT), natural cycling and letrozole ovulation induction during endometrial preparation for frozen-thawed embryo transfer (FET) in patients with normal menstrual cycles. This retrospective analysis included a total of 5070 cycles of patients with normal menstrual patterns who underwent FET between October 2009 and September 2015. The patients were divided into four groups according to the method of endometrial preparation for FET: 1838 cycles were natural, 1666 underwent HRT, 340 underwent letrozole ovulation induction and 1226 underwent modified hMG stimulated. Reproduction-related clinical outcomes in the four groups were compared. The clinical pregnancy rates and live birth rates of patients in the modified hMG stimulated group were significantly higher than that in the other groups p .05). Modified hMG stimulated resulted in a higher pregnancy rate compared to the other treatment groups. Therefore, modified hMG stimulated may be an effective option in endometrial preparation for FET in patients with normal menstrual cycles.

Octacosanol educes physico-chemical attributes, release and bioavailability as modified nanocrystals.

Science.gov (United States)

Sen Gupta, Surashree; Ghosh, Mahua

2017-10-01

Octacosanol is a lesser known nutraceutical with the potential for treatment of several inflammatory diseases, high cholesterol, Parkinson's symptoms and tumour growth along with the capacity to improve athletic performance. But its lipophilicity and large structure inhibits extended solubility in water resulting in poor absorption and a low bioavailability. In the present work, sodium salt of octacosyl sulfate was synthesized. It displayed improved water solubility. Its nanocrystals, synthesized by means of nanoprecipitation technique, enhanced diffusion velocity, antioxidant capacity, shelf-life, penetrability and bioavailability. Particle size of the nanocrystals ranged between 197 and 220nm. Both modified octacosanol and its nanocrystals displayed maximum lipid peroxidation activities at a concentration 1000ppm, but nanocrystals demonstrated higher prevention. From freeze-thaw cycles it was evident that normal octacosanol crystals were far more prone to temperature variations than the nanocrystals. A pronounced increase in release/diffusion rate and bioavailability was observed for the nanocrystals of the modified octacosanol. In vitro release kinetics, bioavailability and bioequivalence were studied. Relative bioavailability for gastric passage and pancreatic passage of nanocrystals was 2.58 times and 1.81 times that of normal crystals respectively. Furthermore the nanocrystals displayed a superior in vitro release rate, while following a non-Fickian mode. Copyright © 2017 Elsevier B.V. All rights reserved.

Waste Material of Propolis as a Film Forming Agent Intended to Modify the Metronidazole Release: Preparation and Characterization.

Science.gov (United States)

de Toledo, Lucas de Alcântara Sica; Rosseto, Hélen Cássia; Ravani, Laura; Cortesi, Rita; Bruschi, Marcos Luciano

2016-01-01

Metronidazole is an antimicrobial agent utilized for the treatment of protozoa and anaerobic bacteria infections. Many times, it is necessary to modify the metronidazole release, and the development of modified release systems may be suggested. In this study, we are able to investigate the use of the residue normally thrown out from the preparation of propolis extracts (BP) as strategy to modify the metronidazole release. We prepared films containing polymeric adjuvant (gelatin or ethylcellulose) and metronidazole, by solvent casting method. Density, mechanical properties, water vapor permeability (WVP), moisture uptake capacity (MUC), thermogravimetry, differential scanning calorimetry, Fourier transform infrared spectroscopy (FT-IR), and in vitro metronidazole release were investigated. Thickness and density of the preparations indicated that the compounds were homogeneously dispersed throughout. Mechanical properties were influenced by film composition. Films containing gelatin showed higher resistance to stress while those containing ethylcellulose presented greater flexibility. The greater the adjuvant concentrations lower the resistance to rupture and the elasticity, but higher MUC and WVP of formulations. FT-IR tests suggested interactions between BP and the adjuvants. Films were capable to protect the metronidazole and changed its release profile. BP films are of great practical importance constituting a novel strategy to modify the metronidazole release.

Degradation testing of Mg alloys in Dulbecco's modified eagle medium: Influence of medium sterilization

International Nuclear Information System (INIS)

Marco, Iñigo; Feyerabend, Frank; Willumeit-Römer, Regine; Van der Biest, Omer

2016-01-01

This work studies the in vitro degradation of Mg alloys for bioabsorbable implant applications under near physiological conditions. For this purpose, the degradation behaviour of Mg alloys in Dulbecco's modified eagle medium (DMEM) which is a commonly used cell culture medium is analysed. Unfortunately, DMEM can be contaminated by microorganisms, acidifying the medium and accelerating the Mg degradation process by dissolution of protective degradation layers, such as (Mg_x,Ca_y)(PO_4)_z. In this paper the influence of sterilization by applying UV-C radiation and antibiotics (penicillin/streptomycin) is analysed with two implant material candidates: Mg–Gd and Mg–Ag alloys; and pure magnesium as well as Mg–4Y–3RE as a reference. - Highlights: • Contamination of DMEM by microorganisms increases the degradation rate of Mg. • Mg and its alloys show passivation during long term immersion tests in DMEM. • The use of a control sample position is essential to assess H_2 evolution in DMEM.

Comparative pharmacokinetics of two modified-release oral morphine formulations (Reliadol® and Kapanol®) and an immediate-release morphine tablet (Morfin 'DAK') in healthy volunteers

DEFF Research Database (Denmark)

Bochner, F.; Somogyi, A.A.; Danz, C.

1999-01-01

, its metabolites morphine-6-glucuronide (M6G) and morphine-3-glucuronide (M3G), after ingestion of Reliadol® (2 x 30 mg capsules) compared with Kapanolo (3 x 20 mg) [Glaxo Wellcome Australia Ltd] and an immediate-release morphine tablet (Morfin 'DAK', 30 mg; Nycomed Denmark A/S). Design and Setting...

The application of povidone in the preparation of modified release tablets

Directory of Open Access Journals (Sweden)

Kasperek Regina

2016-06-01

Full Text Available The aim of the study was to investigate the modified release of a model substance, of tablets containing different types of Kollidon and particular additives. Additionally, the release kinetics and mechanism of prolonged release of certain tablet preparations were investigated. In this work, tablets containing different types of povidone (Kollidon CL, Kollidon 30, Kollidon SR and other excipients were prepared by the direct compression technique. The results showed that tablets with fast disintegration and release should contain in their composition, Kollidon CL, lactose and Avicel, however, the use of β-CD instead of lactose or Avicel brings about a slight prolongation in the disintegration time of tablets and the release of an active substance. Furthermore, while other tablet compositions generated within this study must be considered as being prolonged release types, only two of these showed the best fitted mathematical models. The in vitro dissolution data reveal that the dissolution profiles of the two formulations, one containing Kollidon SR with the addition of Kollidon 30, and the second with HPMC K15M, Kollidon 30, Kollidon CL and lactose, best fitted the Higuchi model. Moreover, the release mechanism of these two formulations plotted well into Korsmeyer-Peppas, indicating a coupling of drug diffusion in the hydrated matrix, as well as polymer relaxation – the so-called anomalous transport (non-Fickian.

Multifunctional Amine Mesoporous Silica Spheres Modified with Multiple Amine as Carriers for Drug Release

Directory of Open Access Journals (Sweden)

Yan Li

2018-01-01

Full Text Available Mesoporous silica spheres were synthesized by using Stöber theory (MSN-40. Calcination of the mesostructured phase resulted in the starting solid. Organic modification with aminopropyl groups resulted in two MSN-40 materials: named MSN-NH2 and MSN-DQ-40, respectively. These two kinds of samples with different pore sizes (obtained from 3-[2-(2-aminoethylaminoethylamino]propyl-trimethox-ysilane (NQ-62 and modified NQ-62 showed control of the delivery rate of ibuprofen (IBU from the siliceous matrix. The obtained sample from modified NQ-62 has an increased loading rate and shows better control of the delivery rate of IBU than the obtained sample from NQ-62. These three solids were characterized using standard solid state procedures. During tests of in vitro drug release, an interesting phenomenon was observed: at high pH (pH 7.45, IBU in all carriers was released slowly; at low pH (pH 4.5, only a part of the IBU was slowly released from this carrier within 25 hours; most IBU was effectively confined in mesoporous material, but the remaining IBU was released rapidly and completely after 25 hours.

Photoresponsive Release from Azobenzene-Modified Single Cubic Crystal NaCl/Silica Particles

Directory of Open Access Journals (Sweden)

Xingmao Jiang

2011-01-01

Full Text Available Azobenzene ligands were uniformly anchored to the pore surfaces of nanoporous silica particles with single crystal NaCl using 4-(3-triethoxysilylpropylureidoazobenzene (TSUA. The functionalization delayed the release of NaCl significantly. The modified particles demonstrated a photocontrolled release by trans/cis isomerization of azobenzene moieties. The addition of amphiphilic solvents, propylene glycol (PG, propylene glycol propyl ether (PGPE, and dipropylene glycol propyl ether (DPGPE delayed the release in water, although the wetting behavior was improved and the delay is the most for the block molecules with the longest carbon chain. The speedup by UV irradiation suggests a strong dependence of diffusion on the switchable pore size. TGA, XRD, FTIR, and NMR techniques were used to characterize the structures.

Development of a Hydrogen Uptake-Release Mg-Based Alloy by Adding a Polymer CMC (Carboxymethylcellulose, Sodium Salt) via Reaction-Accompanying Milling

Science.gov (United States)

Kwak, Young Jun; Choi, Eunho; Song, Myoung Youp

2018-03-01

The addition of carboxymethylcellulose, sodium salt (CMC) might improve the hydrogen uptake and release properties of Mg since it has a relatively low melting point and the melting of CMC during milling in hydrogen (reaction-accompanying milling) may make the milled samples be in good states to absorb and release hydrogen rapidly and to have a large hydrogen-storage capacity. Samples with compositions of 95 w/o Mg + 5 w/o CMC (named Mg-5CMC) and 90 w/o Mg + 10 w/o CMC (named Mg-10CMC) were prepared by adding CMC via reaction-accompanying milling. Activation of Mg-10CMC was completed after about 3 hydrogen uptake-release cycles. Mg-10CMC had a higher initial hydrogen uptake rate and a larger amount of hydrogen absorbed in 60 min, U (60 min), than Mg-5CMC before and after activation. At the cycle number of three (CN = 3), Mg-10CMC had a very high initial hydrogen uptake rate (1.56 w/o H/min) and a large U (60 min) (5.57 w/o H) at 593 K in hydrogen of 12 bar, showing that the activated Mg-10CMC has an effective hydrogen-storage capacity of about 5.6 w/o at 593 K in hydrogen of 12 bar at CN = 3. At CN = 2, Mg-10CMC released 1.00 w/o H in 2.5 min, 4.67 w/o H in 10 min, and 4.76 w/o H in 60 min at 648 K in hydrogen of 1.0 bar. The milling in hydrogen of Mg with CMC is believed to generate imperfections and cracks and reduce the particle size. The addition of 10 w/o CMC was more effective on the initial hydrogen uptake rate and U (60 min) compared with the 10 w/o additions of NbF5, TaF5, Fe2O3, and MnO, and the 10 w/o simultaneous addition of Ni, Fe, and Ti. To the best of our knowledge, this study is the first in which a polymer CMC is added to Mg by reaction-accompanying milling to improve the hydrogen storage properties of Mg.

Synthesis Magnesium Hydroxide Nanoparticles and Cellulose Acetate- Mg(OH2-MWCNT Nanocomposite

Directory of Open Access Journals (Sweden)

M. Ghorbanali

2015-04-01

Full Text Available Mg(OH2 nanoparticles were synthesized by a rapid microwave reaction. The effect of sodium dodecyl sulfonate (SDS as anionic surfactant and cetyl tri-methyl ammonium bromide (CTAB as cationic surfactant on the morphology of magnesium hydroxide nanostructures was investigated. Multi wall carbon nano tubes was organo-modified for better dispersion in cellulose acetate matrix. The influence of Mg(OH2 nanoparticles and modified multi wall carbon nano tubes (MWCNT on the thermal stability of the cellulose acetate (CA matrix was studied using thermo-gravimetric analysis (TGA. Nanostructures were characterized by X-ray diffraction (XRD, scanning electron microscopy (SEM and Fourier transform infrared (FT-IR spectroscopy. Thermal decomposition of the nanocomposites shift towards higher temperature in the presence of Mg(OH2 nanostructures. The enhancement of thermal stability of nanocomposites is due to the endothermic decomposition of Mg(OH2 and release of water which dilutes combustible gases.

Formulation and characterization of modified release tablets containing isoniazid using swellable polymers.

Science.gov (United States)

Akhtar, M F; Rabbani, M; Sharif, A; Akhtar, B; Saleem, A; Murtaza, G

2011-01-01

The aim of this work was to develop swellable modified release (MR) isoniazid tablets using different combinations of polyvinyl acetate (PVAc) and sodium-carboxymethylcellulose (Na-CMC). Granules were prepared by moist granulation technique and then compressed into tablets. In vitro release studies for 12 hr were carried out in dissolution media of varying pH i.e. pH 1.2, 4.5, 7.0 and 7.5. Tablets of all formulations were found to be of good physical quality with respect to appearance (width and thickness), content uniformity, hardness, weight variation and friability. In vitro release data showed that increasing total polymer content resulted in more retarding effect. Formulation with 35% polymer content exhibited zero order release profile and it released 35% of the drug in first hr, later on, controlled drug release was observed upto the 12(th) hour. Formulations with PVAc to Na-CMC ratio 20:80 exhibited zero order release pattern at levels of studied concentrations, which suggested that this combination can be used to formulate zero order release tablets of water soluble drugs like isoniazid. Korsmeyer-Peppas modeling of drug release showed that non-Fickian transport is the primary mechanism of isoniazid release from PVAc and Na-CMC based tablets. The value of mean dissolution time decreased with the increase in the release rate of drug clearly showing the retarding behavior of the swellable polymers. The application of a mixture of PVAc to Na-CMC in a specific ratio may be feasible to formulate zero order release tablets of water soluble drugs like isoniazid.

Optical absorption and thermoluminescence in Mg O, Mg O:Ni and Mg O:Li irradiated at room temperature; Absorcion optica y termoluminiscencia en MgO, MgO:Ni y MgO:Li irradiados a temperatura ambiente

Energy Technology Data Exchange (ETDEWEB)

Delgado, L

1984-07-01

Optical absorption and thermoluminescence (TL) studies in Mg O, Mg O:Ni and Mg O:Li irradiated at room temperature are presented. In pure Mg O the thermal annihilation of Fe3+ by recombination with thermally released electrons at {approx} 90 and 175 degree centigree and the V center annealing by hole release up to 100 degree centigree cause the observed glow peaks at these temperatures. The TL excitation spectrum shows two maxima at 245 nm (electron center) and 288 nm (Fe3+). In Mg O:Ni X irradiation induces Fe{sup 2}+ {yields}- Fe{sup 3}+ and Ni{sup 2}+ {yields} Ni{sup 3}+ oxidations. Two TL emission bands centered at 110 degree centigree (red) and 80 o{sup C} (green) are assigned to electron release and their recombination at Fe{sup 3}+ and Ni{sup 3}+ respectively. In Mg O:Li two TL emission bands, one blue (430 nm) and the other red (730 nm) with excitation maxima at 245 nm (electron center) and 200 nm (hole center) respectively are observed. No V-center formation was detected in both Ni and Li doped samples. (Author) 42 refs.

Maintenance of heartburn relief after step-down from twice-daily proton pump inhibitor to once-daily dexlansoprazole modified release.

Science.gov (United States)

Fass, Ronnie; Inadomi, John; Han, Cong; Mody, Reema; O'Neil, Janet; Perez, M Claudia

2012-03-01

Many patients with gastroesophageal reflux disease (GERD) take a proton pump inhibitor (PPI) twice daily to control symptoms. Once-daily dexlansoprazole modified release (MR) has a dual-delayed release formulation, making it attractive for step-down management of patients whose symptoms are well controlled on twice-daily PPIs. We investigated whether step-down to once-daily dexlansoprazole controls heartburn in patients with GERD who were receiving twice-daily PPI therapy. Patients 18 years and older taking a twice-daily PPI for symptom control were enrolled (n = 178) in a single-blind, multicenter study; 163 patients completed the study and 142 patients met criteria for the efficacy analysis. During the 6-week screening and treatment periods, patients recorded the presence of heartburn symptoms twice daily in electronic diaries. Patients' heartburn was considered well controlled if they had an average of 1 symptom or fewer per week during the last 4 weeks of screening and treatment. After screening, qualified patients were switched to masked dexlansoprazole MR 30 mg and placebo for 6 weeks. The primary efficacy end point was the proportion of patients whose heartburn remained well controlled after step-down. GERD-related symptoms and quality of life (QOL) also were evaluated using the Patient Assessment of Upper Gastrointestinal Disorders Symptom Severity Index (PAGI-SYM) and the PAGI-QOL questionnaires, respectively. After step-down to once-daily dexlansoprazole MR 30 mg, heartburn remained well controlled in 88% of patients (125 of 142). These patients were able to maintain their GERD-related symptom severity and QOL, indicated by marginal changes in the PAGI-SYM and PAGI-QOL total and subscale scores, respectively. Most patients with GERD who take twice-daily PPI to control heartburn are able to successfully step down to once-daily dexlansoprazole 30 mg. Copyright © 2012 AGA Institute. Published by Elsevier Inc. All rights reserved.

Nanostructural drug-inorganic clay composites: Structure, thermal property and in vitro release of captopril-intercalated Mg-Al-layered double hydroxides

International Nuclear Information System (INIS)

Zhang Hui; Zou Kang; Guo Shaohuan; Duan Xue

2006-01-01

A nanostructural drug-inorganic clay composite involving a pharmaceutically active compound captopril (Cpl) intercalated Mg-Al-layered double hydroxides (Cpl-LDHs) with Mg/Al molar ratio of 2.06 has been assembled by coprecipitation method. Powder X-ray diffraction (XRD), Fourier transform infrared spectra (FT-IR) and Raman spectra analysis indicate a successful intercalation of Cpl between the layers with a vertical orientation of Cpl disulphide-containing S-S linkage. SEM photo indicates that as-synthesized Cpl-LDHs possess compact and non-porous structure with approximately and linked elliptical shape particles of ca. 50 nm. TG-DTA analyses suggest that the thermal stability of intercalated organic species is largely enhanced due to host-guest interaction involving the hydrogen bond compared to pure form before intercalation. The in vitro release studies show that both the release rate and release percentages markedly decrease with increasing pH from 4.60 to 7.45 due to possible change of release mechanism during the release process. The kinetic simulation for the release data, and XRD and FT-IR analyses for samples recovered from release media indicate that the dissolution mechanism is mainly responsible for the release behaviour of Cpl-LDHs at pH 4.60, while the ion-exchange one is responsible for that at pH 7.45. - Graphical abstract: Based on XRD, FT-IR and Raman spectra analyses, it is suggested that captopril (Cpl) exists as its disulphide metabolites in the interlayer of Mg-Al-LDHs via hydrogen bonding between guest carboxylate function and hydroxyl group of the host layers. A schematic supramolecular structure of Cpl intercalates involving a vertical orientation of Cpl disulphide-containing S-S bond between the layers with carboxylate anions pointing to both hydroxide layers is presented

Optical absorption and thermoluminescence in Mg O, Mg O:Ni and Mg O:Li irradiated at room temperature

International Nuclear Information System (INIS)

Delgado, L.

1984-01-01

Optical absorption and thermoluminescence (TL) studies in Mg O, Mg O:Ni and Mg O:Li irradiated at room temperature are presented. In pure Mg O the thermal annihilation of Fe3+ by recombination with thermally released electrons at ∼ 90 and 175 degree centigree and the V center annealing by hole release up to 100 degree centigree cause the observed glow peaks at these temperatures. The TL excitation spectrum shows two maxima at 245 nm (electron center) and 288 nm (Fe3+). In Mg O:Ni X irradiation induces Fe 2 + →- Fe 3 + and Ni 2 + → Ni 3 + oxidations. Two TL emission bands centered at 110 degree centigree (red) and 80 o C (green) are assigned to electron release and their recombination at Fe 3 + and Ni 3 + respectively. In Mg O:Li two TL emission bands, one blue (430 nm) and the other red (730 nm) with excitation maxima at 245 nm (electron center) and 200 nm (hole center) respectively are observed. No V-center formation was detected in both Ni and Li doped samples. (Author) 42 refs

Investigation of the combined effect of MgO and PEG on the release profile of mefenamic acid prepared via hot-melt extrusion techniques.

Science.gov (United States)

Alshehri, Sultan M; Tiwari, Roshan V; Alsulays, Bader B; Ashour, Eman A; Alshetaili, Abdullah S; Almutairy, Bjad; Park, Jun-Bom; Morott, Joseph; Sandhu, Bhupinder; Majumdar, Soumyajit; Repka, Michael A

2017-09-01

This study aimed to investigate the combined effect of magnesium oxide (MgO) as an alkalizer and polyethylene glycol (PEG) as a plasticizer and wetting agent in the presence of Kollidon® 12 PF and 17 PF polymer carriers on the release profile of mefenamic acid (MA), which was prepared via hot-melt extrusion technique. Various drug loads of MA and various ratios of the polymers, PEG 3350 and MgO were blended using a V-shell blender and extruded using a twin-screw extruder (16-mm Prism EuroLab, ThermoFisher Scientific, Carlsbad, CA) at different screw speeds and temperatures to prepare a solid dispersion system. Differential scanning calorimetry and X-ray diffraction data of the extruded material confirmed that the drug existed in the amorphous form, as evidenced by the absence of corresponding peaks. MgO and PEG altered the micro-environmental pH to be more alkaline (pH 9) and increased the hydrophilicity and dispersibility of the extrudates to enhance MA solubility and release, respectively. The in vitro release study demonstrated an immediate release for 2 h with more than 80% drug release within 45 min in matrices containing MgO and PEG in combination with polyvinylpyrrolidone when compared to the binary mixture, physical mixture and pure drug.

In-situ investigation of the hydrogen release mechanism in bulk Mg2NiH4

Science.gov (United States)

Tran, Xuan Quy; McDonald, Stuart D.; Gu, Qinfen; Yamamoto, Tomokazu; Shigematsu, Koji; Aso, Kohei; Tanaka, Eishi; Matsumura, Syo; Nogita, Kazuhiro

2017-02-01

Hydrogen storage is an important aspect to enable the so-called hydrogen economy. Mg-Ni alloys are among the most promising candidates for solid-state hydrogen storage systems yet many questions remain unanswered regarding the hydriding/dehydriding mechanism of the alloys. Mg2NiH4 particularly has received much attention both for its potential as a hydrogen storage medium and also exhibits interesting properties relating to its different polymorphs. Here, the dehydriding mechanism in bulk Mg2NiH4 is investigated using in-situ ultra-high voltage transmission electron microscopy (TEM) combined with Synchrotron powder X-ray diffraction (XRPD) and differential scanning calorimetry (DSC). We find that the hydrogen release is based on a mechanism of nucleation and growth of Mg2NiHx (x∼0-0.3) solid solution grains and is greatly enhanced in the presence of crystal defects occurring as a result of the polymorphic phase transformation. Also importantly, with atomic resolution TEM imaging a high density of stacking faults is identified in the dehydrided Mg2NiHx (x∼0-0.3) lattices.

Strengthening and toughening of poly(L-lactide) composites by surface modified MgO whiskers

Energy Technology Data Exchange (ETDEWEB)

Wen, Wei [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Luo, Binghong, E-mail: tluobh@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Qin, Xiaopeng; Li, Cairong [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Liu, Mingxian; Ding, Shan [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China); Zhou, Changren, E-mail: tcrz9@jnu.edu.cn [Biomaterial Research Laboratory, Department of Material Science and Engineering, College of Science and Engineering, Jinan University, Guangzhou 510632 (China); Engineering Research Center of Artificial Organs and Materials, Ministry of Education, Guangzhou 510632 (China)

2015-03-30

Highlights: • The grafted PLLA chain on the surface of g-MgO whisker was ruled out by FTIR spectroscopy and TG/DTG analyses. • The excellent dispersion of g-MgO whiskers and the strong interfacial adhesion of g-MgO whiskers/PLLA composite were proved by FSEM. • Comparing to MgO particles and MgO whiskers, fibrous-like g-MgO whiskers are the most effective reinforcing and toughening fillers for PLLA. - Abstract: To improve both the strength and toughness of poly(L-lactide) (PLLA), fibrous-like MgO whiskers with diameters of 0.15–1 μm and lengths of 15–110 μm were prepared, and subsequently surface modified with L-lactide to obtain grafted MgO whiskers (g-MgO whiskers). The structures and properties of MgO whiskers and g-MgO whiskers were studied. Then, a series of MgO whiskers/PLLA and g-MgO whiskers/PLLA composites were prepared by solution casting method, for comparison, MgO particles/PLLA composite was prepared too. The resulting composites were evaluated in terms of hydrophilicity, crystallinity, dispersion of whiskers, interfacial adhesion and mechanical performance by means of polarized optical microscopy (POM), contact angle measurement, field emission scanning electron microscope (FSEM), transmission electron microscopy (TEM) and tensile testing. The results revealed that the crystallization rate and hydrophilicity of PLLA were improved by the introduction of MgO whiskers and g-MgO whiskers. The g-MgO whiskers can disperse more uniformly in and show stronger interfacial adhesion with the matrix than MgO whiskers as a result of the surface modification. Due to the bridge effect of the whiskers and the excellent interfacial adhesion between g-MgO whiskers and PLLA, g-MgO whiskers/PLLA composites exhibited remarkably higher strength, modulus and toughness compared to the pristine PLLA, MgO particles/PLLA and MgO whiskers/PLLA composites.

Development of Modified-Release Tablets of Zolpidem Tartrate by Biphasic Quick/Slow Delivery System

OpenAIRE

Mahapatra, Anjan Kumar; Sameeraja, N. H.; Murthy, P. N.

2014-01-01

Zolpidem tartrate is a non-benzodiazepine analogue of imidazopyridine of sedative and hypnotic category. It has a short half-life with usual dosage regimen being 5 mg, two times a day, or 10 mg, once daily. The duration of action is considered too short in certain circumstances. Thus, it is desirable to lengthen the duration of action. The formulation design was implemented by preparing extended-release tablets of zolpidem tartrate using the biphasic delivery system technology, where sodium s...

41 CFR 102-37.465 - May a SASP modify or release any of the terms and conditions of donation?

Science.gov (United States)

2010-07-01

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Shock and Release Data on Forsterite (Mg2SiO4) Single Crystals

Science.gov (United States)

Root, S.; Townsend, J. P.; Shulenburger, L.; Davies, E.; Kraus, R. G.; Spaulding, D.; Stewart, S. T.; Jacobsen, S. B.; Mattsson, T. R.

2016-12-01

The Kepler mission has discovered numerous extra-solar rocky planets with sizes ranging from Earth-size to the super-Earths with masses 40 times larger than Earth. The solid solution series of (Mg, Fe)2SiO4 (olivine) is a major component in the mantle of Earth and likely these extra-solar rocky planets. However, understanding how the (Mg, Fe)2SiO4 system behaves at Earth like and super-Earth like pressures is still unknown. Using Sandia's Z machine facility, we shock compress single crystal forsterite, the Mg end-member of the olivine series. Solid aluminum flyers are accelerated up to 28 km/s to generate steady shock states up to 950 GPa. Release states from the Hugoniot are determined as well. In addition to experiments, we perform density functional theory (DFT) calculations to examine the potential phases along the Mg2SiO4 Hugoniot. We compare our results to other recent shock experiments on forsterite. Sandia National Laboratories is a multiprogram laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under Contract No. DE-AC04-94AL85000. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

Natural gums and modified natural gums as sustained-release carriers.

Science.gov (United States)

Bhardwaj, T R; Kanwar, M; Lal, R; Gupta, A

2000-10-01

Although natural gums and their derivatives are used widely in pharmaceutical dosage forms, their use as biodegradable polymeric materials to deliver bioactive agents has been hampered by the synthetic materials. These natural polysaccharides do hold advantages over the synthetic polymers, generally because they are nontoxic, less expensive, and freely available. Natural gums can also be modified to have tailor-made materials for drug delivery systems and thus can compete with the synthetic biodegradable excipients available in the market. In this review, recent developments in the area of natural gums and their derivatives as carriers in the sustained release of drugs are explored.

Preliminary assessment of framework conditions for release of genetically modified mosquitoes in Burkina Faso.

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De Freece, Chenoa; Paré Toé, Léa; Esposito, Fulvio; Diabaté, Abdoulaye; Favia, Guido

2014-09-01

Genetically modified mosquitoes (GMMs) are emerging as a measure to control mosquito-borne diseases, but before any genetically modified organisms (GMOs) are released into the environment, it is imperative to establish regulatory standards incorporating public engagement. A previous project in Burkina Faso introduced a type of genetically modified cotton [Bacillus thuringiensis (Bt)] cotton) that produces insecticide, and incorporated policies on public engagement. We explored the perspectives of Burkinabè (citizens of Burkina Faso) on bio-agricultural exposure to GMOs and their receptiveness to the use of GMOs. Interviews were conducted in a village (Bondoukuy) and with representatives from stakeholder organizations. The population may be very receptive to the use of GMMs against malaria, but may voice unfounded concerns that GMMs can transmit other diseases. It is important to constantly supply the population with correct and factual information. Investigating the application of Burkina Faso's biotechnology policies with regard to Bt cotton has shown that it may be conceivable in the future to have open discussions about the merits of GMM release. © The Author 2014. Published by Oxford University Press on behalf of Royal Society of Tropical Medicine and Hygiene. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Comparative kinetic studies of Mn2+-activated and fructose-1,6-P-modified Mg2+-activated pyruvate kinase from Concholepas concholepas.

Science.gov (United States)

Carvajal, N; González, R; Morán, A; Oyarce, A M

1985-01-01

Initial velocity and product inhibition studies of Mn2+-activated and FDP-modified Mg2+-activated pyruvate kinase from Concholepas concholepas, were performed. Evidence is presented to show that the Mn2+-enzyme catalyzes an ordered sequential mechanism, with ADP being the first substrate and pyruvate the last product. The results presented are consistent with a random combination of reactants with the FDP-modified Mg2+-activated enzyme and the formation of the dead-end complexes enzyme ADP-ATP and enzyme-PEP-ATP.

Degradation testing of Mg alloys in Dulbecco's modified eagle medium: Influence of medium sterilization

Energy Technology Data Exchange (ETDEWEB)

Marco, Iñigo, E-mail: inigo.marco@mtm.kuleuven.be [Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg, 44, 3001 Leuven (Belgium); Feyerabend, Frank; Willumeit-Römer, Regine [Institute of Materials Research, Division Metallic Biomaterials, Helmholtz-Zentrum Geesthacht, Max-Planck-Str., 1, 21502 Geesthacht (Germany); Van der Biest, Omer [Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg, 44, 3001 Leuven (Belgium)

2016-05-01

This work studies the in vitro degradation of Mg alloys for bioabsorbable implant applications under near physiological conditions. For this purpose, the degradation behaviour of Mg alloys in Dulbecco's modified eagle medium (DMEM) which is a commonly used cell culture medium is analysed. Unfortunately, DMEM can be contaminated by microorganisms, acidifying the medium and accelerating the Mg degradation process by dissolution of protective degradation layers, such as (Mg{sub x},Ca{sub y})(PO{sub 4}){sub z}. In this paper the influence of sterilization by applying UV-C radiation and antibiotics (penicillin/streptomycin) is analysed with two implant material candidates: Mg–Gd and Mg–Ag alloys; and pure magnesium as well as Mg–4Y–3RE as a reference. - Highlights: • Contamination of DMEM by microorganisms increases the degradation rate of Mg. • Mg and its alloys show passivation during long term immersion tests in DMEM. • The use of a control sample position is essential to assess H{sub 2} evolution in DMEM.

Chronotherapy with low-dose modified-release prednisone for the management of rheumatoid arthritis: a review

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Beltrametti SP

2016-11-01

Full Text Available Stefano Paolo Beltrametti,1 Aurora Ianniello,2 Clara Ricci3 1Department of Rheumatology, S. Andrea Hospital, Vercelli, 2Rheumatology Outpatient Clinic, Novara, 3Primula Multimedia S.p.A, Pisa, Italy Abstract: To date, rheumatoid arthritis (RA remains a debilitating, life-threatening disease. One major concern is morning symptoms (MS, as they considerably impair the patients’ quality of life and ability to work. MS change in a circadian fashion, resembling the fluctuations of inflammatory cytokines such as interleukin-6, whose levels are higher in RA patients compared to healthy donors. Conversely, serum levels of the potent anti-inflammatory glucocorticoid cortisol are similar to that of healthy subjects, suggesting an imbalance that sustains a pro-inflammatory state. From a therapeutic point of view, administering synthetic glucocorticoids (GCs to RA patients represents an optimal strategy to provide for the inadequate levels of cortisol. Indeed, due to their high efficacy in RA, GCs remain a cornerstone more than 60 years after their first introduction, and despite the development of a wide range of targeted agents. However, to improve safety, low-dose GCs have been introduced, that have demonstrated high efficacy in reducing disease activity, radiological progression, and improving patients’ signs and symptoms especially in early RA when added to conventional disease-modifying antirheumatic drugs. A further improvement has been provided by the development of modified-release prednisone, which, by taking advantage of the circadian fluctuations of inflammatory cytokines, cortisol and MS, is given at bedtime to be released approximately 4 hours later. Several studies have already demonstrated the efficacy of this agent on disease activity, MS, and quality of life in the setting of established RA. Moreover, preliminary studies have shown that this new formulation not only has no impact on the adrenal function, but likely improves it. This

Development of modified release 3D printed tablets (printlets) with pharmaceutical excipients using additive manufacturing.

Science.gov (United States)

Goyanes, Alvaro; Fina, Fabrizio; Martorana, Annalisa; Sedough, Daniel; Gaisford, Simon; Basit, Abdul W

2017-07-15

The aim of this study was to manufacture 3D printed tablets (printlets) from enteric polymers by single filament fused deposition modeling (FDM) 3D printing (3DP). Hot melt extrusion was used to generate paracetamol-loaded filaments from three different grades of the pharmaceutical excipient hypromellose acetate succinate (HPMCAS), grades LG, MG and HG. One-step 3DP was used to process these filaments into enteric printlets incorporating up to 50% drug loading with two different infill percentages (20 and 100%). X-ray Micro Computed Tomography (Micro-CT) analysis revealed that printlets with 20% infill had cavities in the core compared to 100% infill, and that the density of the 50% drug loading printlets was higher than the equivalent formulations loaded with 5% drug. In biorelevant bicarbonate dissolution media, drug release from the printlets was dependent on the polymer composition, drug loading and the internal structure of the formulations. All HPMCAS-based printlets showed delayed drug release properties, and in the intestinal conditions, drug release was faster from the printlets prepared with polymers with a lower pH-threshold: HPMCAS LG > HPMCAS MG > HPMCAS HG. These results confirm that FDM 3D printing makes it possible not only to manufacture delayed release printlets without the need for an outer enteric coating, but it is also feasible to adapt the release profile in response to the personal characteristics of the patient, realizing the full potential of additive manufacturing in the development of personalised dose medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

Surface modified zeolite-based granulates for the sustained release of diclofenac sodium.

Science.gov (United States)

Serri, Carla; de Gennaro, Bruno; Quagliariello, Vincenzo; Iaffaioli, Rosario Vincenzo; De Rosa, Giuseppe; Catalanotti, Lilia; Biondi, Marco; Mayol, Laura

2017-03-01

In this study, a granulate for the oral controlled delivery of diclofenac sodium (DS), an anionic sparingly soluble nonsteroidal anti-inflammatory drug, has been realized by wet granulation, using a surface modified natural zeolite (SMNZ) as an excipient. The surface modification of the zeolite has been achieved by means of a cationic surfactant, so as to allow the loading of DS through ionic interaction and bestow a control over the drug release mechanism. The granules possessed a satisfactory dosage uniformity, a flowability suitable for an oral dosage form manufacturing, along with a sustained drug release up to 9h, driven by both ion exchange and transport kinetics. Furthermore, the obtained granulate did not elicit a significant cytotoxicity and could also induce a prolonged anti-inflammatory effect on RAW264.7 cells. Taking also into account that natural zeolites are generally abundant and economic, SMNZ can be considered as an attracting alternative excipient for the production of granules with sustained release features. Copyright © 2016 Elsevier B.V. All rights reserved.

The effect of two types of modified Mg-Al hydrotalcites on reinforcement corrosion in cement mortar

NARCIS (Netherlands)

Yang, Z.; Polder, R.; Mol, J.M.C.; Andrade, C.

2017-01-01

Two modified Mg-Al hydrotalcites (MHTs), (MHT-pAB and MHT-NO2) were incorporated into mortar (with different w/c ratios) in two different ways: (1) as one of the mixing components in bulk mortar; (2) as part of cement paste coating of the reinforcing steel. Accelerated chloride migration, cyclic

Novel Brassinosteroid-Modified Polyethylene Glycol Micelles for Controlled Release of Agrochemicals.

Science.gov (United States)

Pérez Quiñones, Javier; Brüggemann, Oliver; Kjems, Jørgen; Shahavi, Mohammad Hassan; Peniche Covas, Carlos

2018-02-21

Two synthetic analogues of brassinosteroids (DI31 and S7) exhibit good plant growth enhancer activity. However, their hydrophobicity and quick metabolism in plants have limited their application and benefits in agriculture. Our objective was to prepare novel brassinosteroid-modified polyethylene glycol (PEG) micelles to achieve controlled release with extended stability while retaining agrochemical activity. Spectroscopic studies confirmed quantitative disubstitution of studied PEGs with the brassinosteroids, while elemental analysis assessed purity of the synthesized conjugates. Conjugates were also characterized by X-ray diffraction and thermal analysis. Dynamic and static light scattering showed stable and homogeneous approximately spherical micelles with average hydrodynamic diameters of 22-120 nm and almost neutral ζ potential. Spherical 30-140 nm micelles were observed by electron microscopy. Sustained in vitro releases at pH 5.5 were extended up to 96 h. Prepared PEG micelles showed good agrochemical activity in the radish seed bioassay and no cytotoxicity to the human microvascular endothelial cell line in the MTS test.

Pharmacokinetics and Pharmacodynamics of Tamsulosin in its Modified-Release and Oral Controlled Absorption System Formulations

NARCIS (Netherlands)

Franco-Salinas, Gabriela; de La Rosette, Jean J. M. C. H.; Michel, Martin C.

2010-01-01

Tamsulosin is an alpha(1)-adrenoceptor antagonist used for the treatment of lower urinary tract symptoms that are suggestive of benign prostatic hyperplasia. It is mostly used in a modified-release (M R) Formulation. but an oral controlled absorption system (OCAS) and a 'without-water' tablet

SH Oxidation Stimulates Calcium Release Channels (Ryanodine Receptors From Excitable Cells

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CECILIA HIDALGO

2000-01-01

Full Text Available The effects of redox reagents on the activity of the intracellular calcium release channels (ryanodine receptors of skeletal and cardiac muscle, or brain cortex neurons, was examined. In lipid bilayer experiments, oxidizing agents (2,2'-dithiodipyridine or thimerosal modified the calcium dependence of all single channels studied. After controlled oxidation channels became active at sub µM calcium concentrations and were not inhibited by increasing the calcium concentration to 0.5 mM. Subsequent reduction reversed these effects. Channels purified from amphibian skeletal muscle exhibited the same behavior, indicating that the SH groups responsible for modifying the calcium dependence belong to the channel protein. Parallel experiments that measured calcium release through these channels in sarcoplasmic reticulum vesicles showed that following oxidation, the channels were no longer inhibited by sub mM concentrations of Mg2+. It is proposed that channel redox state controls the high affinity sites responsible for calcium activation as well as the low affinity sites involved in Mg2+ inhibition of channel activity. The possible physiological and pathological implications of these results are discussed

Characterization of modified allergen extracts by in vitro beta-hexosaminidase release from rat basophils.

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Gehlhar, Kirsten; Peters, Marcus; Brockmann, Kirsten; van Schijndel, Hans; Bufe, Albrecht

2005-04-01

To date, there is no well-established test available that can be used to measure functional properties of modified allergens (allergoids). Due to the cross-linking process, the IgE-binding capacity of the allergens, normally necessary for their characterization, is lost. The aim of this study was to test whether the rat basophilic leukaemia (RBL) cell assay (beta-hexosaminidase release by rat basophils upon allergen stimulation) can be adopted to characterize allergoids and to evaluate the assay for testing allergoids and native allergens as well. Mice were immunized with native and modified Phleumpratense extracts in the presence of alum. Their sera were used to sensitize RBL-2H3 cells and measure basophil stimulation induced by different allergen extracts in the presence or absence of various additives. Sera containing specific IgE against both extract formulations were obtained. Native as well as modified extracts induced dose-dependent beta-hexosaminidase release from RBL cells. Both extracts were used to evaluate the characteristics of the assay, which showed high precision. Storage conditions were chosen to enhance extract degradation, which could be read directly from the altered stimulatory capacity of the extracts. Additives turned out to have diverse effects on the assay, whereas phenol had no measurable effect, alum had an inhibitory effect and glycerol elevated basophil activation. For the first time, a reliable, precise in vitro assay is available that is able to directly measure the properties of modified allergen extracts after their production process. The test is well evaluated and its advantages and limitations are discussed in this report. Copyright (c) 2005 S. Karger AG, Basel

Soluble salts addition modifies MgO hydration

International Nuclear Information System (INIS)

Santos, A.M.; Pandolfelli, V.C.; Salomao, R.

2012-01-01

Magnesium oxide (MgO) show great technological interest on refractories due to its high refractoriness, basic slag corrosion resistance and competitive cost. However, the hydration reaction of MgO produces magnesium hydroxide. This reaction generates a significant volumetric expansion that can lead to material breakdown inhibiting its use in refractory castables. This reaction can be affected by several factors such as magnesia source, purity, calcination temperature, pH, CaO/SiO 2 ratio and agitation speed. In the present work, soluble salts (CaCl 2 and MgCl 2 ) were used in MgO aqueous suspensions (caustic and sinter). The results were evaluated by means of techniques of degree of hydration (termogravimetric), Scanning electron microscopy, apparent volumetric expansion and x-ray Diffraction which showed that the degree of hydration was noticeably less to sinter aqueous and the expansive effects were less with the addition of CaCl 2 . (author)

Formulation and evaluation of sustained release matrix tablets of pioglitazone hydrochloride using processed Aloe vera mucilage as release modifier

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Manoj Choudhary

2015-01-01

Full Text Available Background: Natural gums and mucilage which hydrates and swells on contact with aqueous media are used as additives in the formulation of hydrophilic drug delivery system. Aim: The purpose of this study was to develop a new monolithic matrix system for complete delivery of Pioglitazone hydrochloride (HCl, in a zero-order manner over an extended time period using processed Aloe vera gel mucilage (PAG as a release modifier. Materials and Methods: The matrices were prepared by dry blending of selected ratios of polymer and ingredients using direct compression technique. Physicochemical properties of dried powdered mucilage of A. vera were studied. Various formulations of pioglitazone HCl and A. vera mucilage were prepared using different drug: Polymer ratios viz., 1:1, 1:2, 1:3, 1:4, 1:5 for PAG by direct compression technique. Results: The formulated matrix tablets were found to have better uniformity of weight and drug content with low statistical deviation. The swelling behavior and in vitro release rate characteristics were also studied. Conclusion: The study proved that the dried A. vera mucilage can be used as a matrix forming material for controlled release of Pioglitazone HCl matrix tablets.

Understanding long-term silver release from surface modified porous titanium implants.

Science.gov (United States)

Shivaram, Anish; Bose, Susmita; Bandyopadhyay, Amit

2017-08-01

Prevention of orthopedic device related infection (ODRI) using antibiotics has met with limited amount of success and is still a big concern during post-surgery. As an alternative, use of silver as an antibiotic treatment to prevent surgical infections is being used due to the well-established antimicrobial properties of silver. However, in most cases silver is used in particulate form with wound dressings or with short-term devices such as catheters but not with load-bearing implants. We hypothesize that strongly adherent silver to load-bearing implants can offer longer term solution to infection in vivo. Keeping that in mind, the focus of this study was to understand the long term release study of silver ions for a period of minimum 6months from silver coated surface modified porous titanium implants. Implants were fabricated using a LENS™ system, a powder based additive manufacturing technique, with at least 25% volume porosity, with and without TiO 2 nanotubes in phosphate buffer saline (pH 7.4) to see if the total release of silver ions is within the toxic limit for human cells. Considering the fact that infection sites may reduce the local pH, silver release was also studied in acetate buffer (pH 5.0) for a period of 4weeks. Along with that, the osseointegrative properties as well as cytotoxicity of porous titanium implants were assessed in vivo for a period of 12weeks using a rat distal femur model. In vivo results indicate that porous titanium implants with silver coating show comparable, if not better, biocompatibility and bonding at the bone-implant interface negating any concerns related to toxicity related to silver to normal cells. The current research is based on our recently patented technology, however focused on understanding longer-term silver release to mitigate infection related problems in load-bearing implants that can even arise several months after the surgery. Prevention of orthopedic device related infection using antibiotics has met

Origin of the modified orientation relationship for S(S'')-phase in Al-Mg-Cu alloys

International Nuclear Information System (INIS)

Kovarik, L.; Miller, M.K.; Court, S.A.; Mills, M.J.

2006-01-01

The formation of S-phase with a modified orientation relationship (OR) has been previously observed in several Al-Cu-Mg alloys. In this paper, high-resolution transmission electron microscopy and Z-contrast imaging have been used to study the origin of the modified OR in an alloy with low Cu/Mg ratio and small Si addition. Based on the observations, and supported by ab initio simulations, the formation is governed by coherency at the (0 2 1) S //(0 1 4) Al S-phase/matrix interface, which is shown to coexist with the more commonly reported (0 0 1) S //(0 2 1) Al interface. This new (0 2 1) S //(0 1 4) Al S-phase/matrix interface explanation is compared with previously published explanations based on the invariant line concept and establishment of a different S-phase/matrix interface. Energy dispersive X-ray spectroscopy and atom probe tomography indicate that the S-phase is slightly enriched in Si. The role of Si as well as the overall alloy composition is discussed. Because of the similarities between our results and the early work of Bagaryatsky, the S''-phase notation is adopted for this early-forming, strained version of the S-phase

Factors affecting release of ethanol vapour in active modified atmosphere packaging systems for horticultural products

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Weerawate Utto

2014-04-01

Full Text Available The active modified atmosphere packaging (active MAP system , which provides interactive postharvest control , using ethanol vapour controlled release, is one of the current interests in the development of active packaging for horticultural products. A number of published research work have discussed the relationship between the effectiveness of ethanol vapour and its concentration in the package headspace, including its effect on postharvest decay and physiological controls. This is of importance because a controlled release system should release and maintain ethanol vapour at effective concentrations during the desired storage period. A balance among the mass transfer processes of ethanol vapour in the package results in ethanol vapour accumulation in the package headspace. Key factors affecting these processes include ethanol loading, packaging material, packaged product and storage environment (temperature and relative h umidity. This article reviews their influences and discusses future work required to better understand their influences on ethanol vapour release and accumulations in active MAP.

In vitro metal ion release and biocompatibility of amorphous Mg67Zn28Ca5 alloy with/without gelatin coating

International Nuclear Information System (INIS)

Chan, W.Y.; Chian, K.S.; Tan, M.J.

2013-01-01

Amorphous zinc-rich Mg–Zn–Ca alloys have exhibited good tissue compatibility and low hydrogen evolution in vivo. However, suboptimal cell–surface interaction on magnesium alloy surface observed in vitro could lead to reduced integration with host tissue for regenerative purpose. This study aims to improve cell–surface interaction of amorphous Mg 67 Zn 28 Ca 5 alloy by coating a gelatin layer by electrospinning. Coated/uncoated alloys were immersed and extracted for 3 days under different CO 2 . The immersion results showed that pH and metal ion release in the alloy extracts were affected by gelatin coating and CO 2 , suggesting their roles in alloy biocorrosion and a mechanism has been proposed for the alloy–CO 2 system with/without coating. Cytotoxicity results are evident that gelatin-coated alloy with 2-day crosslinking not only exhibited no indirect cytotoxicity, but also supported attachment of L929 and MG63 cell lines around/on the alloy with high viability. Therefore, amorphous Mg 67 Zn 28 Ca 5 alloy coated with gelatin by electrospinning technique provides a useful method to improve alloy biocompatibility. - Highlights: • Electrospinning is a new method to coat amorphous Mg 67 Zn 28 Ca 5 alloy with gelatin. • Gelatin-coated alloy has differential effect on pH and ion release at various CO 2 . • L929 cell proliferation correlates with Mg 2+ level in alloy extracts. • Biomimetic gelatin coating significantly improves cell–surface interaction

High-precision ²⁷Al/²⁴Mg ratio determination using a modified isotope-dilution approach

DEFF Research Database (Denmark)

Paton, Chad; Schiller, Martin; Ulfbeck, David Garf

2012-01-01

saves time and minimises the risk of contamination of other samples with spike (which is added immediately prior to analysis). Repeat measurements of the BHVO-2, BCR-2, and BIR-1 international rock standards, as well as a gravimetrically prepared Al–Mg reference solution, indicate that our method......The precision of the 26Al–26Mg system—one of the most widely used chronometers for constraining the relative timing of events in the early solar system—is presently limited by methods for the determination of 27Al/24Mg ratios, which have seen little improvement in the last decade. We present...... a novel method for the measurement of 27Al/24Mg ratios in unpurified sample solutions by multiple-collector inductively coupled plasma mass spectrometry. Because Al is monoisotopic we use a modified isotope dilution approach that employs a mixed spike containing isotopically enriched 25Mg and natural 27Al...

Design and evaluation of nicorandil extended-release tablet

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Ju-Young Kim

2015-04-01

Full Text Available The aim of this study was to design and evaluate extended-release formulations of a model drug, nicorandil, in order to achieve the desired steady-state plasma concentration of drug in vivo. Simulation was employed to estimate optimum dissolution and absorption rate of nicorandil. The dissolution test was employed using pH 1.2, 4.0, 6.8 buffer solution, or water, to measure the in vitro release behaviors of nicorandil formulations. A single dose (15 mg of each formulation was orally administered to four beagle dogs under fasted conditions, and the pharmacokinetic parameters were calculated. The in vitro/in vivo relationship of the extended-release formulation was confirmed using in vitro dissolution profiles and plasma concentrations of drug in beagle dogs. Nicorandil was released completely within 30 min from the immediate-release tablets and released for 24 h from the extended-release tablets. The nicorandil plasma concentration could be modified by adjusting the drug release rate from the extended-release formulation. The release rate of nicorandil was the rate-limiting step in the overall absorption of drug from the extended-release formulations. These results highlight the potential of a nicorandil extended-release formulation in the treatment of angina pectoris.

The systems containing clays and clay minerals from modified drug release: a review.

Science.gov (United States)

Rodrigues, Luís Alberto de Sousa; Figueiras, Ana; Veiga, Francisco; de Freitas, Rivelilson Mendes; Nunes, Lívio César Cunha; da Silva Filho, Edson Cavalcanti; da Silva Leite, Cleide Maria

2013-03-01

Clays are materials commonly used in the pharmaceutical industry, either as ingredients or as active ingredients. It was observed that when they are administered concurrently, they may interact with drugs reducing their absorption. Therefore, such interactions can be used to achieve technological and biopharmaceutical advantages, regarding the control of release. This review summarizes bibliographic (articles) and technological (patents) information on the use of systems containing clays and clay minerals in modified drug delivery. In this area, formulations such natural clay, commercial clay, synthetic clay, composites clay-polymers, nanocomposites clay-polymers, films and hidrogels composites clay-polymers are used to slow/extend or vectorize the release of drugs and consequently they increase their bioavailability. Finally, this review summarizes the fields of technology and biopharmaceutical applications, where clays are applied. Copyright © 2012 Elsevier B.V. All rights reserved.

Modifying release characteristics from 3D printed drug-eluting products

DEFF Research Database (Denmark)

Boetker, Johan; Water, Jorrit; Aho, Johanna

2016-01-01

Abstract This work describes an approach to modify the release of active compound from a 3D printed model drug product geometry intended for flexible dosing and precision medication. The production of novel polylactic acid and hydroxypropyl methylcellulose based feed materials containing...... nitrofurantoin for 3D printing purposes is demonstrated. Nitrofurantoin, Metolose® and polylactic acid were successfully co-extruded with up to 40% Metolose® content, and subsequently 3D printed into model disk geometries (ø10 mm, h = 2 mm). Thermal analysis with differential scanning calorimetry and solid phase...... identification with Raman spectroscopy showed that nitrofurantoin remained in its original solid form during both hot-melt extrusion and subsequent 3D printing. Rheological measurements of the different compositions showed that the flow properties were sensitive to the amount of undissolved particles present...

Ovarian dynamics in response to two modified intravaginal progesterone releasing device and oestradiol benzoate based ovulation synchronisation protocols designed for use in Brahman heifers.

Science.gov (United States)

Edwards, S A A; Atkinson, P C; Satake, N; Boe-Hansen, G; McGowan, M R

2014-07-01

The objective was to investigate the ovarian response of Brahman heifers to two modified ovulation synchronisation protocols developed to increase the proportion of normal synchronous ovulations. Experiment 1 characterised the growth of the ovulatory follicle in heifers (n=19) treated with an intravaginal progesterone releasing device (IPRD) and oestradiol benzoate (ODB), to determine the optimal time to induce ovulation. Using the findings from Experiment 1, Experiment 2 investigated the effect of reducing the duration of IPRD insertion and increasing the interval from IPRD removal to ODB treatment (modified protocol 1 - OPO-6; n=20), and omitting ODB treatment at the time of IPRD insertion (modified protocol 2 - PO-6; n=20). An IPRD (0.78 g progesterone) was inserted at Day 0 (OPO-8) or Day 2 (OPO-6 and PO-6) and all heifers also received 1 mg ODB i.m. Day 8: IPRD removed + 500 μg cloprostenol i.m. At 24 h (OPO-8) and 36 h (OPO-6 and PO-6) post IPRD removal: 1 mg ODB i.m. Fixed-time AI (FTAI) occurred at 54 h for OPO-8 and 72 h for OPO-6 and PO-6, post IPRD removal. After IPRD treatment all OPO-6 and OPO-8 heifers initiated a new follicular wave whereas 25% of PO-6 heifers failed. Diameter of the dominant follicle was larger at FTAI in the PO-6 (11.34 ± 0.50 mm) compared to the OPO-8 protocol (9.74 ± 0.51 mm; P<0.05), but similar to the OPO-6 protocol (10.52 ± 0.51 mm). Proportion of ovulations occurring 12 h prior and 24 h post FTAI was similar for the PO-6 (80%) and OPO-6 (75%) protocols but numerically lower in the OPO-8 heifers (60%). The apparent improvement in ovarian response in heifers treated with the modified protocols needs to be confirmed in larger field studies. Copyright © 2014 Elsevier B.V. All rights reserved.

MgO nanobelt-modified graphene-tantalum wire electrode for the simultaneous determination of ascorbic acid, dopamine and uric acid

International Nuclear Information System (INIS)

Zhao, Liwei; Li, Hongji; Gao, Sumei; Li, Mingji; Xu, Sheng; Li, Cuiping; Guo, Wenlong; Qu, Changqing; Yang, Baohe

2015-01-01

Graphical abstract: Display Omitted -- Highlights: •Graphene and MgO nanobelts are deposited on tantalum wires to form biosensors. •Ascorbic acid, dopamine and uric acid are determined with the biosensors. •The biosensors show high electrocatalytic activity for oxidation of these species. •The biosensors show high selectivity and good sensitivity. -- ABSTRACT: A promising electrochemical biosensor for simultaneous detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA) was fabricated by electrochemical deposition of MgO nanobelts on a graphene-modified tantalum wire (denoted as MgO/Gr/Ta) electrode. The MgO nanobelts and graphene were verified by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Electrochemical performances of the electrodes were characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The CV results show that AA, DA and UA could be detected simultaneously using MgO/Gr/Ta electrode with peak-to-peak separation of 300 mV, 147 mV and 447 mV for AA-DA, DA-UA and AA-UA, respectively. In the threefold co-existence system, the linear calibration plots for AA, DA and UA were obtained over the concentration range of 5.0–350 μM, 0.1–7 μM and 1–70 μM with detection limits of 0.03 μM, 0.15 μM and 0.12 μM, respectively. The modified electrode shows excellent selectivity, good sensitivity and good stability, making it attractive as a sensor for simultaneous detection of AA, DA and UA in biological fluids

Improved virus removal in ceramic depth filters modified with MgO.

Science.gov (United States)

Michen, Benjamin; Fritsch, Johannes; Aneziris, Christos; Graule, Thomas

2013-02-05

Ceramic filters, working on the depth filtration principle, are known to improve drinking water quality by removing human pathogenic microorganisms from contaminated water. However, these microfilters show no sufficient barrier for viruses having diameters down to 20 nm. Recently, it was shown that the addition of positively charged materials, for example, iron oxyhydroxide, can improve virus removal by adsorption mechanisms. In this work, we modified a common ceramic filter based on diatomaceous earth by introducing a novel virus adsorbent material, magnesium oxyhydroxide, into the filter matrix. Such filters showed an improved removal of about 4-log in regard to bacteriophages MS2 and PhiX174. This is explained with the electrostatic enhanced adsorption approach that is the favorable adsorption of negatively charged viruses onto positively charged patches in an otherwise negatively charged filter matrix. Furthermore, we provide theoretical evidence applying calculations according to Derjaguin-Landau-Verwey-Overbeek theory to strengthen our experimental results. However, modified filters showed a significant variance in virus removal efficiency over the course of long-term filtration experiments with virus removal increasing with filter operation time (or filter aging). This is explained by transformational changes of MgO in the filter upon contact with water. It also demonstrates that filter history is of great concern when filters working on the adsorption principles are evaluated in regard to their retention performance as their surface characteristics may alter with use.

Catalytic Micromotors Moving Near Polyelectrolyte-Modified Substrates: The Roles of Surface Charges, Morphology, and Released Ions.

Science.gov (United States)

Wei, Mengshi; Zhou, Chao; Tang, Jinyao; Wang, Wei

2018-01-24

Synthetic microswimmers, or micromotors, are finding potential uses in a wide range of applications, most of which involve boundaries. However, subtle yet important effects beyond physical confinement on the motor dynamics remain less understood. In this letter, glass substrates were functionalized with positively and negatively charged polyelectrolytes, and the dynamics of micromotors moving close to the modified surfaces was examined. Using acoustic levitation and numerical simulation, we reveal how the speed of a chemically propelled micromotor slows down significantly near a polyelectrolyte-modified surface by the combined effects of surface charges, surface morphology, and ions released from the films.

Coumarin-modified microporous-mesoporous Zn-MOF-74 showing ultra-high uptake capacity and photo-switched storage/release of U{sup VI} ions

Energy Technology Data Exchange (ETDEWEB)

Zhang, Le; Wang, Lin Lin; Gong, Le Le; Feng, Xue Feng; Luo, Ming Biao; Luo, Feng, E-mail: ecitluofeng@163.com

2016-07-05

Graphical abstract: Table of content Herein, through coordination-based post-synthetic strategy, microporous-mesoporous Zn-MOF-74 was easily functionalized by grafting coumarin on coordinatively unsaturated Zn(II) centers, yielding a series of coumarin-modified Zn-MOF-74 materials. The obtained samples afforded ultra-high adsorption capacity for UVI ions from water with maximum adsorption capacities as high as 360 mg/g (the record value in MOFs) and remarkable photo-switched capability of 50 mg/g. - Highlights: • This work shows the record uptake capability of U{sup VI} (360 mg/g) in MOFs. • This work shows, for the first time, photo-switching behaviour towards U{sup VI} in aqueous solution. • This work demonstrates a simple and effective method to largely enhance uptake capability of U{sup VI}. • This work demonstrates a distinct method to prepare photo-sensitive MOFs for photo-switching behaviour towards guest molecules. - Abstract: Driven by an energy crisis but consequently puzzled by various environmental problems, uranium, as the basic material of nuclear energy, is now receiving extensive attentions. In contrast to numerous sorbents applied in this field, metal-organic framework (MOFs), as a renovated material platform, has only recently been developed. How to improve the adsorption capacity of MOF materials towards U{sup VI} ions, as well as taking advantage of the nature of these MOFs to design photo-switched behaviour for photo-triggered storage/release of U{sup VI} ions are at present urgent problems and great challenges to be solved. Herein, we show a simple and facile method to target the goal. Through coordination-based post-synthetic strategy, microporous- mesoporous Zn-MOF-74 was easily functionalized by grafting coumarin on coordinatively unsaturated Zn(II) centers, yielding a series of coumarin-modified Zn-MOF-74 materials. The obtained samples displayed ultra-high adsorption capacity for U{sup VI} ions from water at pH value of 4 with

Biological and mechanical properties of an experimental glass-ionomer cement modified by partial replacement of CaO with MgO or ZnO

Directory of Open Access Journals (Sweden)

Dong-Ae KIM

2015-08-01

Full Text Available AbstractSome weaknesses of conventional glass ionomer cement (GIC as dental materials, for instance the lack of bioactive potential and poor mechanical properties, remain unsolved.Objective The purpose of this study was to investigate the effects of the partial replacement of CaO with MgO or ZnO on the mechanical and biological properties of the experimental glass ionomer cements.Material and Methods Calcium fluoro-alumino-silicate glass was prepared for an experimental glass ionomer cement by melt quenching technique. The glass composition was modified by partial replacement (10 mol% of CaO with MgO or ZnO. Net setting time, compressive and flexural properties, and in vitrorat dental pulp stem cells (rDPSCs viability were examined for the prepared GICs and compared to a commercial GIC.Results The experimental GICs set more slowly than the commercial product, but their extended setting times are still within the maximum limit (8 min specified in ISO 9917-1. Compressive strength of the experimental GIC was not increased by the partial substitution of CaO with either MgO or ZnO, but was comparable to the commercial control. For flexural properties, although there was no significance between the base and the modified glass, all prepared GICs marked a statistically higher flexural strength (p<0.05 and comparable modulus to control. The modified cements showed increased cell viability for rDPSCs.Conclusions The experimental GICs modified with MgO or ZnO can be considered bioactive dental materials.

Biological and mechanical properties of an experimental glass-ionomer cement modified by partial replacement of CaO with MgO or ZnO

Science.gov (United States)

Dong-Ae, KIM; Hany, ABO-MOSALLAM; Hye-Young, LEE; Jung-Hwan, LEE; Hae-Won, KIM; Hae-Hyoung, LEE

2015-01-01

Some weaknesses of conventional glass ionomer cement (GIC) as dental materials, for instance the lack of bioactive potential and poor mechanical properties, remain unsolved. Objective The purpose of this study was to investigate the effects of the partial replacement of CaO with MgO or ZnO on the mechanical and biological properties of the experimental glass ionomer cements. Material and Methods Calcium fluoro-alumino-silicate glass was prepared for an experimental glass ionomer cement by melt quenching technique. The glass composition was modified by partial replacement (10 mol%) of CaO with MgO or ZnO. Net setting time, compressive and flexural properties, and in vitro rat dental pulp stem cells (rDPSCs) viability were examined for the prepared GICs and compared to a commercial GIC. Results The experimental GICs set more slowly than the commercial product, but their extended setting times are still within the maximum limit (8 min) specified in ISO 9917-1. Compressive strength of the experimental GIC was not increased by the partial substitution of CaO with either MgO or ZnO, but was comparable to the commercial control. For flexural properties, although there was no significance between the base and the modified glass, all prepared GICs marked a statistically higher flexural strength (p<0.05) and comparable modulus to control. The modified cements showed increased cell viability for rDPSCs. Conclusions The experimental GICs modified with MgO or ZnO can be considered bioactive dental materials. PMID:26398508

Effects of modified surfaces produced at plasma-facing surface on hydrogen release behavior in the LHD

Directory of Open Access Journals (Sweden)

Y. Nobuta

2017-08-01

Full Text Available In the present study, an additional deuterium (D ion irradiation was performed against long-term samples mounted on the helical coil can and in the outer private region in the LHD during the 17th experimental campaign. Based on the release behavior of the D and hydrogen (H retained during the experimental campaign, the difference of release behavior at the top surface and in bulk of modified surfaces is discussed. Almost all samples on the helical coil can were erosion-dominant and some samples were covered with boron or carbon, while a very thick carbon films were formed in the outer private region. In the erosion-dominant area, the D desorbed at much lower temperatures compared to that of H retained during the LHD plasma operation. For the samples covered with boron, the D tended to desorb at lower temperatures compared to H. For the carbon deposition samples, the D desorbed at much higher temperatures compared to no deposition and boron-covered samples, which was very similar to that of H. The D retention capabilities at the top surface of carbon and boron films were 2–3 times higher than no deposition area. The results indicate that the retention and release behavior at the top surface of the modified layer can be different from that of bulk substrate material.

Modified hydrotalcite-like compounds as active fillers of biodegradable polymers for drug release and food packaging applications.

Science.gov (United States)

Costantino, Umberto; Nocchetti, Morena; Tammaro, Loredana; Vittoria, Vittoria

2012-11-01

This review treats the recent patents and related literature, mainly from the Authors laboratories, on biomedical and food packaging applications of nano-composites constituted of biodegradable polymers filled with micro or nano crystals of organically modified Layered Double Hydroxides of Hydrotalcite type. After a brief outline of the chemical and structural aspects of Hydrotalcite-like compounds (HTlc) and of their manipulation via intercalation of functional molecular anions to obtain materials for numerous, sometime unexpected applications, the review approaches the theme in three separated parts. Part 1 deals with the synthetic method used to prepare the pristine Mg-Al and Zn-Al HTlc and with the procedures of their functionalization with anti-inflammatory (diclofenac), antibacterial (chloramphenicol hemisuccinate), antifibrinolytic (tranexamic acid) drugs and with benzoates with antimicrobial activity. Procedures used to form (nano) composites of polycaprolactone, used as an example of biodegradable polymer, and functionalized HTlc are also reported. Part 2 discusses a patent and related papers on the preparation and biomedical use of a controlled delivery system of the above mentioned pharmacologically active substances. After an introduction dealing with the recent progress in the field of local drug delivery systems, the chemical and structural aspects of the patented system constituted of a biodegradable polymer and HTlc loaded with the active substances will be presented together with an extensive discussion of the drug release in physiological medium. Part 3 deals with a recent patent and related papers on chemical, structural and release property of antimicrobial species of polymeric films containing antimicrobial loaded HTlc able to act as active packaging for food products prolonging their shelf life.

Controlled release of moxifloxacin from intraocular lenses modified by Ar plasma-assisted grafting with AMPS or SBMA: An in vitro study.

Science.gov (United States)

Pimenta, A F R; Vieira, A P; Colaço, R; Saramago, B; Gil, M H; Coimbra, P; Alves, P; Bozukova, D; Correia, T R; Correia, I J; Guiomar, A J; Serro, A P

2017-08-01

Intraocular lenses (IOLs) present an alternative for extended, local drug delivery in the prevention of post-operative acute endophthalmitis. In the present work, we modified the surface of a hydrophilic acrylic material, used for manufacturing of IOLs, through plasma-assisted grafting copolymerization of 2-acrylamido-2-methylpropane sulfonic acid (AMPS) or [2-(methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA), with the aim of achieving a controlled and effective drug release. The material was loaded with moxifloxacin (MFX), a commonly used antibiotic for endophthalmitis prevention. The characterization of the modified material showed that relevant properties, like swelling capacity, wettability, refractive index and transmittance, were not affected by the surface modification. Concerning the drug release profiles, the most promising result was obtained when AMPS grafting was done in the presence of MFX. This modification led to a higher amount of drug being released for a longer period of time, which is a requirement for the prevention of endophthalmitis. The material was found to be non-cytotoxic for rabbit corneal endothelial cells. In a second step, prototype IOLs were modified with AMPS and loaded with MFX as previously and, after sterilization and storage (30days), they were tested under dynamic conditions, in a microfluidic cell with volume and renovation rate similar to the eye aqueous humour. MFX solutions collected in this assay were tested against Staphylococcus aureus and Staphylococcus epidermidis and the released antibiotic proved to be effective against both bacteria until the 12th day of release. Copyright © 2017 Elsevier B.V. All rights reserved.

Influence of Nanomaterial Compatibilization Strategies on Polyamide Nanocomposites Properties and Nanomaterial Release during the Use Phase.

Science.gov (United States)

Fernández-Rosas, Elisabet; Vilar, Gemma; Janer, Gemma; González-Gálvez, David; Puntes, Victor; Jamier, Vincent; Aubouy, Laurent; Vázquez-Campos, Socorro

2016-03-01

The incorporation of small amounts of nanofillers in polymeric matrices has enabled new applications in several industrial sectors. The nanofiller dispersion can be improved by modifying the nanomaterial (NM) surface or predispersing the NMs to enhance compatibility. This study evaluates the effect of these compatibilization strategies on migration/release of the nanofiller and transformation of polyamide-6 (PA6), a thermoplastic polymer widely used in industry during simulated outdoors use. Two nanocomposites (NCs) containing SiO2 nanoparticles (NPs) with different surface properties and two multiwalled carbon nanotube (MWCNT) NCs obtained by different addition methods were produced and characterized, before and after accelerated wet aging conditions. Octyl-modified SiO2 NPs, though initially more aggregated than uncoated SiO2 NPs, reduced PA6 hydrolysis and, consequently, NM release. Although no clear differences in dispersion were observed between the two types of MWCNT NCs (masterbatch vs direct addition) after manufacture, the use of the MWCNT masterbatch reduced PA6 degradation during aging, preventing MWCNT accumulation on the surface and further release or potential exposure by direct contact. The amounts of NM released were lower for MWCNTs (36 and 108 mg/m(2)) than for SiO2 NPs (167 and 730 mg/m(2)), being lower in those samples where the NC was designed to improve the nanofiller-matrix interaction. Hence, this study shows that optimal compatibilization between NM and matrix can improve NC performance, reducing polymer degradation and exposure and/or release of the nanofiller.

The physical properties and ion release of CPP-ACP-modified calcium silicate-based cements.

Science.gov (United States)

Dawood, A E; Manton, D J; Parashos, P; Wong, Rhk; Palamara, Jea; Stanton, D P; Reynolds, E C

2015-12-01

This study investigated the physical properties and ion release of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP)-modified calcium silicate-based cements (CSCs) and compared the properties of a trial mineral trioxide aggregate (MTA) with two commercially available CSCs, Biodentine(™) and Angelus(®) MTA. The setting time, solubility, compressive strength and Vickers surface microhardness of the three CSCs incorporated with 0%, 0.5%, 1.0%, 2.0% and 3.0% (w/w) CPP-ACP were investigated. Release of calcium (Ca(2+) ), phosphate ions (Pi ) and pH of the test cements were measured after 24, 72, 168 and 336 h of storage. The addition of up to 1.0% CPP-ACP into Biodentine(™) and 0.5% into the other cements did not adversely affect their physical properties except for the setting time. The addition of 0.5% CPP-ACP increased Ca(2+) released from Biodentine(™) (after 168 and 336 h), Angelus(®) MTA (after 168 h) and the trial MTA (after 72 h). The addition of 1.0-3.0% CPP-ACP increased Ca(2+) and Pi released from all the cements. Biodentine(™) released more Ca(2+) particularly in the early stages and showed shorter setting time and higher mechanical properties than the other cements. The mechanical properties of Angelus(®) MTA and the trial MTA were similar. All the cements produced highly alkaline storage solutions. Up to 1.0% CPP-ACP in Biodentine(™) improves Ca(2+) and Pi release and 0.5% CPP-ACP in Angelus(®) MTA and the trial MTA improves Ca(2+) release without altering the mechanical properties and solubility. The addition of CPP-ACP into CSCs prolonged the setting time. © 2015 Australian Dental Association.

Surface modified natural zeolite as a carrier for sustained diclofenac release: A preliminary feasibility study.

Science.gov (United States)

de Gennaro, Bruno; Catalanotti, Lilia; Cappelletti, Piergiulio; Langella, Alessio; Mercurio, Mariano; Serri, Carla; Biondi, Marco; Mayol, Laura

2015-06-01

In view of zeolite potentiality as a carrier for sustained drug release, a clinoptilolite-rich rock from California (CLI_CA) was superficially modified with cetylpyridinium chloride and loaded with diclofenac sodium (DS). The obtained surface modified natural zeolites (SMNZ) were characterized by confocal scanning laser microscopy (CLSM), powder X-ray diffraction (XRPD) and laser light scattering (LS). Their flowability properties, drug adsorption and in vitro release kinetics in simulated intestinal fluid (SIF) were also investigated. CLI_CA is a Na- and K-rich clinoptilolite with a cationic exchange ability that fits well with its zeolite content (clinoptilolite=80 wt%); the external cationic exchange capacity is independent of the cationic surfactant used. LS and CLSM analyses have shown a wide distribution of volume diameters of SMNZ particles that, along with their irregular shape, make them cohesive with scarce flow properties. CLSM observation has revealed the localization of different molecules in/on SMNZ by virtue of their chemical nature. In particular, cationic and polar probes prevalently localize in SMNZ bulk, whereas anionic probes preferentially arrange themselves on SMNZ surface and the loading of a nonpolar molecule in/on SMNZ is discouraged. The adsorption rate of DS onto SMNZ was shown by different kinetic models highlighting the fact that DS adsorption is a pseudo-second order reaction and that the diffusion through the boundary layer is the rate-controlling step of the process. DS release in an ionic medium, such as SIF, can be sustained for about 5h through a mechanism prevalently governed by anionic exchange with a rapid final phase. Copyright © 2015 Elsevier B.V. All rights reserved.

Synthesis and characterization of thermosensitive hydrogels and the investigation of modified release of ibuprofen

Directory of Open Access Journals (Sweden)

Ilić-Stojanović Snežana S.

2013-01-01

Full Text Available The method of the synthesis of poly(N-isopropylacrylamide-co-2-hydroxypropyl methacrylate hydrogels obtained by radical polymerization is described. Their characterization was carried out by the determination of the quantity of residual monomers and by investigating their structure using the FTIR. Three glass transitions were detected by DSC method. The porous surfaces of hydrogels with incorporated ibuprofen were shown in SEM micrographs. The swelling ratio of hydrogels decreased with the temperature increase and the swelling transport mechanism was changed from non-Fickian to Fickian. Ibuprofen was incorporated in hydrogel as a drug carrier and released quantity was monitored by HPLC method depending on the temperature. Hydrogel with the lower cross-linker content had the highest swelling degree (α = 34.72 at 10°C and released the largest amount of ibuprofen (64.21 mg/gxerogel at 40°C. [Projekat Ministarstva nauke Republike Srbije, br. TR-34012

Corrosion behaviors of Mg and its alloys with different Al contents in a modified simulated body fluid

International Nuclear Information System (INIS)

Wen Zhaohui; Wu Changjun; Dai Changsong; Yang Feixia

2009-01-01

The corrosion behaviors of pure magnesium (Mg) and three Mg alloys with different Al contents were investigated in a modified simulated body fluid (m-SBF) through immersion tests, Tafel experiments, and electrochemical impedance spectroscopic (EIS) experiments. The immersion results show that the corrosion rates (CRs) of the four samples were in an order of AZ91D ct ) of the three magnesium alloys initially increased and then decreased while the R ct of pure Mg was kept lower within 24 h. The results of a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) show that pure Mg and three alloys were heterogeneously corroded in the m-SBF. The corrosion of pure Mg, which showed a more uniform corrosion appearance, resulted from localized corrosion over the entire surface. Alloy AZ91D (of 8.5-9.5 wt.% Al) showed relatively uniform corrosion morphology and the β-Mg 12 Al 17 precipitates in alloy AZ91D were more homogeneously and continuously distributed along the grain boundaries. Obvious corrosion pits were found on the surface of alloy AZ61 and AZ31. The corrosion pits of alloy AZ61 were shallower than those of alloy AZ31. Alloy AZ61 (of 5.8-7.2 wt.% Al) possessed more Al 8 Mn 5 and a little β-Mg 12 Al 17 presented along the grain boundary heterogeneously and discontinuously. Al 8 Mn 5 was the main phase of the AZ31 alloy (of 2.5-3.5 wt.% Al) dispersed into the matrix. In conclusion, the microstructure and the Al content in the α-Mg (Al) matrix significantly affected the corrosion properties of the alloys in the m-SBF. With the increase in Al content, the corrosion resistances of the samples were improved.

Effects of iron on intermetallic compound formation in scandium modified Al–Si–Mg Alloys

Energy Technology Data Exchange (ETDEWEB)

Patakham, Ussadawut [National Metal and Materials Technology Center, National Science and Technology Development Agency, 114 Thailand Science Park, Klong Nueng, Klong Luang, Pathumthani 12120 (Thailand); Limmaneevichitr, Chaowalit, E-mail: chaowalit.lim@mail.kmutt.ac.th [Production Engineering Department, Faculty of Engineering, King Mongkut’s University of Technology Thonburi, 126 Pracha-Utid Rd., Bangmod, Tungkhru, Bangkok 10140 (Thailand)

2014-12-15

Highlights: • Iron reduces the modification effects of scandium in Al–Si–Mg alloys. • Morphologies of Sc-rich intermetallic phases vary with Fe and Sc contents and the cooling rates. • Sc neutralizes effects of Fe by changing Fe-rich intermetallic phases from platelets to more cubic. - Abstract: In general, iron has a strong tendency to dissolve in molten aluminum. Iron has very low solid solubility in aluminum–silicon casting alloys, so it will form intermetallic compounds that cause detrimental effects on mechanical properties. In this work, the effects of iron on intermetallic compound formations in scandium modified Al–Si–Mg alloys were studied. There were two levels of iron addition (0.2 and 0.4 wt.%) and two levels of scandium addition (0.2 and 0.4 wt.%). We found that the effects of scandium modification decreased with increasing iron addition. The morphologies of the complex intermetallic compounds were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and electron backscatter diffraction (EBSD) techniques. It was found that scandium changes the morphology of Fe-rich intermetallic compounds from β-phase (plate-like) to α-phase, which reduces the harmful effects of β-phase.

Mechanical strengths of modified PET mortar composites in aggressive MgSO4 medium: ACI & B.S predictions

OpenAIRE

Kazi Tani N; Benosman A.S.; Senhadji Y.; Taïbi H.; Mouli M.

2018-01-01

Composites mortars based on plastic aggregates are often considered as an innovative materials of the future because of their potential and the advantages they present. In this paper, a comparative study was carried out on the effect of magnesium sulfate MgSO4 (5%) attack on the durability of composite mortars modified by recycled polyethylene terephthalate (PET). Laboratory tests were accomplished on limestone sand and cement mortars where the blended Portland cement was partially replaced b...

Microstructure, mechanical properties and bio-corrosion properties of Mg-Si(-Ca, Zn) alloy for biomedical application.

Science.gov (United States)

Zhang, Erlin; Yang, Lei; Xu, Jianwei; Chen, Haiyan

2010-05-01

Mg-Si alloy was investigated for biomedical application due to the biological function of Si in the human body. However, Mg-Si alloy showed a low ductility due to the presence of coarse Mg(2)Si. Ca and Zn elements were used to refine and modify the morphology of Mg(2)Si in order to improve the corrosion resistance and the mechanical properties. The cell toxicity of Mg, Zn and Ca metals was assessed by an MTT test. The test results indicated that increasing the concentrations of Mg, Zn and Ca ions did not cause cell toxicity, which showed that the release of these three elements would not lead to cell toxicity. Then, microstructure, mechanical properties and bio-corrosion properties of as-cast Mg-Si(-Ca, Zn) alloys were investigated by optical microscopy, scanning electronic microscopy, mechanical properties testing and electrochemical measurement. Ca element can slightly refine the grain size and the morphology Mg(2)Si phase in Mg-Si alloy. The bio-corrosion resistance of Mg-Si alloys was improved by the addition of Ca due to the reduction and refinement of Mg(2)Si phase; however, no improvement was observed in the strength and elongation. The addition of 1.6% Zn to Mg-0.6Si can modify obviously the morphology of Mg(2)Si phase from course eutectic structure to a small dot or short bar shape. As a result, tensile strength, elongation and bio-corrosion resistance were all improved significantly; especially, the elongation improved by 115.7%. It was concluded that Zn element was one of the best alloying elements of Mg-Si alloy for biomedical application. Copyright (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Heparin modified graphene oxide for pH-sensitive sustained release of doxorubicin hydrochloride

Energy Technology Data Exchange (ETDEWEB)

Zhang, Baomei; Yang, Xiaoye; Wang, Yang; Zhai, Guangxi, E-mail: professorgxzhai@126.com

2017-06-01

A novel nanocarrier of heparin (Hep) modified graphene oxide (GO) was fabricated via a linker (adipic dihydrazide) and used as a pH-sensitive drug delivery system for controlling the release of anticancer drug doxorubicin (DOX) for anti-tumor therapy. The finally obtained nanocarrier was GO-ADH-Hep with better stability, blood compatibility and biocompatibility confirmed by the hemolytic test and in vitro cytotoxicity study. Its safety issue was greatly improved via Hep modification. The amount of DOX loaded onto GO-ADH-Hep was significantly high and dependent on pH value. The release rate of DOX from GO- ADH-Hep/DOX was pH-sensitive and much-slower than that of free DOX solution suggesting the sustained drug-release capacity of this prepared nanocomplexes. In addition, the results of cytotoxicity study illustrated that this fabricated nanocomplexes displayed effective cytotoxicity to MCF-7 and HepG2 cells. What's more, the results of the in vivo pharmacokinetic study was also indicated that the GO-ADH-Hep/DOX nanocomplexes could significantly prolong the retention time of DOX in vivo and this was consistent with the in vitro drug release performance. And finally, according to the biodistribution study, DOX delivered by GO-ADH-Hep could reduce cardiotoxicity deriving from DOX solution and also decrease the pulmonary toxicity deriving from unmodified GO. Based on the in vitro and in vivo investigations, the fabricated GO-ADH-Hep could be a promising candidate as an ideal nano-carrier for drug delivery and anti-cancer therapy. - Highlights: • Firstly, a novel nanocarrier-GO-ADH-Hep was fabricated with improved stability, little cytotoxicity and little hemolysis ratio. • Secondly, GO-ADH-Hep was used to load the anticancer drug (DOX) with high drug loading and pH-sensitive sustained drug release. • Thirdly, the anti-cancer efficacy of GO-ADH-Hep/DOX was dose- and time-dependent in vitro. • Finally, according to the in vivo studies, this synthesized nano

Multi-unit dosage formulations of theophylline for controlled release applications.

Science.gov (United States)

Uhumwangho, Michael U; Okor, Roland S

2007-01-01

The study was carried out to investigate the drug release profiles of multi-unit dosage formulations of theophylline consisting of both the fast and slow release components in a unit dose. The fast release component consisted of conventional granules of theophylline formed by mixing the drug powder with starch mucilage (20% w/v) while the slow release component consisted of wax granulations of theophylline formed by triturating the drug powder with a melted Carnauba wax (drug:wax ratio, 4:1). The granules were either filled into capsules or tabletted. In the study design, the drug release characteristics of the individual fast or slow release particles were first determined separately and then mixed in various proportions for the purpose of optimizing the drug release profiles. The evaluating parameters were the prompt release in the first 1 h (mp), the maximum release (m infinity) and the time to attain it (t infinity). Total drug content in each capsule or tablet was 300 mg and two of such were used in dissolution studies. The release kinetics and hence the release mechanism was confirmed by measuring the linear regression coefficient (R2 values) of the release data. The release kinetics was generally most consistent with the Higuchi square root of time relationship (R2 = 0.95). indicating a diffusion-controlled mechanism. The mp (mg) and t infinity (h) values for capsules and tablets of the conventional granules were (420 mg, 3 h) and (348 mg, 5 h), respectively, while for the capsules and tablets of the wax granulations mp and t infinity values were (228 mg, 9 h) and (156 mg, 12 h), respectively, indicating that a combination of wax granulation and tableting markedly retarded drug release. In the multi-unit dose formulations where the conventional and wax granulations were mixed in the ratios 2:1, 1:1 and 1:2 (conventional: matrix), the m infinity and t infinity values for the capsules were (378 mg, 6 h), (326 mg, 6 h) and (272 mg, 7 h), reSpectively. The

In vitro metal ion release and biocompatibility of amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy with/without gelatin coating

Energy Technology Data Exchange (ETDEWEB)

Chan, W.Y., E-mail: chan.wing.yue@sgh.com.sg [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore); Department of Plastic, Reconstructive and Aesthetic Surgery, Singapore General Hospital (Singapore); Chian, K.S.; Tan, M.J. [School of Mechanical and Aerospace Engineering, Nanyang Technological University (Singapore)

2013-12-01

Amorphous zinc-rich Mg–Zn–Ca alloys have exhibited good tissue compatibility and low hydrogen evolution in vivo. However, suboptimal cell–surface interaction on magnesium alloy surface observed in vitro could lead to reduced integration with host tissue for regenerative purpose. This study aims to improve cell–surface interaction of amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy by coating a gelatin layer by electrospinning. Coated/uncoated alloys were immersed and extracted for 3 days under different CO{sub 2}. The immersion results showed that pH and metal ion release in the alloy extracts were affected by gelatin coating and CO{sub 2}, suggesting their roles in alloy biocorrosion and a mechanism has been proposed for the alloy–CO{sub 2} system with/without coating. Cytotoxicity results are evident that gelatin-coated alloy with 2-day crosslinking not only exhibited no indirect cytotoxicity, but also supported attachment of L929 and MG63 cell lines around/on the alloy with high viability. Therefore, amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy coated with gelatin by electrospinning technique provides a useful method to improve alloy biocompatibility. - Highlights: • Electrospinning is a new method to coat amorphous Mg{sub 67}Zn{sub 28}Ca{sub 5} alloy with gelatin. • Gelatin-coated alloy has differential effect on pH and ion release at various CO{sub 2}. • L929 cell proliferation correlates with Mg{sup 2+} level in alloy extracts. • Biomimetic gelatin coating significantly improves cell–surface interaction.

Corrosion behaviors of Mg and its alloys with different Al contents in a modified simulated body fluid

Energy Technology Data Exchange (ETDEWEB)

Wen Zhaohui [Department of Ultrasound, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Wu Changjun, E-mail: wucj163@126.co [Department of Ultrasound, First Affiliated Hospital of Harbin Medical University, Harbin 150001 (China); Dai Changsong, E-mail: changsd@hit.edu.c [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China); Yang Feixia [School of Chemistry Engineering and Technology, Harbin Institute of Technology, Harbin 150001 (China)

2009-11-20

The corrosion behaviors of pure magnesium (Mg) and three Mg alloys with different Al contents were investigated in a modified simulated body fluid (m-SBF) through immersion tests, Tafel experiments, and electrochemical impedance spectroscopic (EIS) experiments. The immersion results show that the corrosion rates (CRs) of the four samples were in an order of AZ91D < AZ61 < AZ31 < pure Mg after immersion for 1 day. With an increase in immersion time, their corrosion rates decreased and then a stable stage was reached after 16 days. The order of CRs of the four samples changed to AZ91D < pure Mg < AZ61 < AZ31 after immersion for 24 days. The results of EIS experiments indicate that the charge transfer resistance (R{sub ct}) of the three magnesium alloys initially increased and then decreased while the R{sub ct} of pure Mg was kept lower within 24 h. The results of a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) show that pure Mg and three alloys were heterogeneously corroded in the m-SBF. The corrosion of pure Mg, which showed a more uniform corrosion appearance, resulted from localized corrosion over the entire surface. Alloy AZ91D (of 8.5-9.5 wt.% Al) showed relatively uniform corrosion morphology and the {beta}-Mg{sub 12}Al{sub 17} precipitates in alloy AZ91D were more homogeneously and continuously distributed along the grain boundaries. Obvious corrosion pits were found on the surface of alloy AZ61 and AZ31. The corrosion pits of alloy AZ61 were shallower than those of alloy AZ31. Alloy AZ61 (of 5.8-7.2 wt.% Al) possessed more Al{sub 8}Mn{sub 5} and a little {beta}-Mg{sub 12}Al{sub 17} presented along the grain boundary heterogeneously and discontinuously. Al{sub 8}Mn{sub 5} was the main phase of the AZ31 alloy (of 2.5-3.5 wt.% Al) dispersed into the matrix. In conclusion, the microstructure and the Al content in the {alpha}-Mg (Al) matrix significantly affected the corrosion properties of the alloys in the m-SBF. With the increase

Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

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Ligi, Marco; Bonatti, Enrico; Cuffaro, Marco; Brunelli, Daniele

2013-01-01

The seawater Mg/Ca ratio increased significantly from ~ 80 Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ocean occur in fast spreading, East Pacific Rise-type ridges. The Mesozoic Pangean superocean implies a hot fast spreading ridge system. This prevented peridotite-seawater interaction and Mg release to the Mesozoic ocean, but favored hydrothermal Mg capture and Ca release by the basaltic crust, resulting in a low seawater Mg/Ca ratio. Continent dispersal and development of slow spreading ridges allowed Mg release to the ocean by peridotite-seawater reactions, contributing to the increase of the Mg/Ca ratio of post-Mesozoic seawater. PMID:24067442

Enhanced J c property in nano-SiC doped thin MgB2/Fe wires by a modified in situ PIT process

International Nuclear Information System (INIS)

Jiang, C.H.; Nakane, T.; Hatakeyama, H.; Kumakura, H.

2005-01-01

A modified in situ PIT process, which included a short time pre-annealing and intermediate drawing step in the conventional in situ PIT process, was employed to fabricate thin round MgB 2 /Fe wires from MgH 2 and B powders. The pores and cracks resulted from the MgH 2 decomposition during the pre-annealing were effectively eliminated by the intermediate drawing step, which subsequently increased the core density and J c property of final heat treated wires. A higher reduction rate after the pre-annealing led to a larger enhancement in J c within this study. The reproducibility of our new process on the J c improvement in MgB 2 wires was confirmed in two series of wires doped with 5 mol% or 10 mol% nano-SiC particles separately

Tracing subduction zone fluid-rock interactions using trace element and Mg-Sr-Nd isotopes

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Wang, Shui-Jiong; Teng, Fang-Zhen; Li, Shu-Guang; Zhang, Li-Fei; Du, Jin-Xue; He, Yong-Sheng; Niu, Yaoling

2017-10-01

Slab-derived fluids play a key role in mass transfer and elemental/isotopic exchanges in subduction zones. The exhumation of deeply subducted crust is achieved via a subduction channel where fluids from various sources are abundant, and thus the chemical/isotopic compositions of these rocks could have been modified by subduction-zone fluid-rock interactions. Here, we investigate the Mg isotopic systematics of eclogites from southwestern Tianshan, in conjunction with major/trace element and Sr-Nd isotopes, to characterize the source and nature of fluids and to decipher how fluid-rock interactions in subduction channel might influence the Mg isotopic systematics of exhumed eclogites. The eclogites have high LILEs (especially Ba) and Pb, high initial 87Sr/86Sr (up to 0.7117; higher than that of coeval seawater), and varying Ni and Co (mostly lower than those of oceanic basalts), suggesting that these eclogites have interacted with metamorphic fluids mainly released from subducted sediments, with minor contributions from altered oceanic crust or altered abyssal peridotites. The positive correlation between 87Sr/86Sr and Pb* (an index of Pb enrichment; Pb* = 2*PbN/[CeN + PrN]), and the decoupling relationships and bidirectional patterns in 87Sr/86Sr-Rb/Sr, Pb*-Rb/Sr and Pb*-Ba/Pb spaces imply the presence of two compositionally different components for the fluids: one enriched in LILEs, and the other enriched in Pb and 87Sr/86Sr. The systematically heavier Mg isotopic compositions (δ26Mg = - 0.37 to + 0.26) relative to oceanic basalts (- 0.25 ± 0.07) and the roughly negative correlation of δ26Mg with MgO for the southwestern Tianshan eclogites, cannot be explained by inheritance of Mg isotopic signatures from ancient seafloor alteration or prograde metamorphism. Instead, the signatures are most likely produced by fluid-rock interactions during the exhumation of eclogites. The high Rb/Sr and Ba/Pb but low Pb* eclogites generally have high bulk-rock δ26Mg values

A miniaturized Microwave Bandpass Filter Based on Modified (Mg0.95Ca0.05TiO3 Substrate

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Hu Mingzhe

2016-01-01

Full Text Available A microwave miniaturized bandpass filter using (Mg0.95Ca0.05TiO3 (abbreviated as 95MCT hereafter ceramic substrate is investigated in the present paper. The paper studies the sintering and microwave dielectric properties of Al2O3, La2O3 and SiO2 co-doped 95MCT. The XRD pattern shows that a secondary phase MgTi2O5 is easily segregated in 95MCT ceramic, however, through co-doping it can be effectively suppressed, and the microwave dielectric properties, especially, the Qf value can be significantly improved. Through optimizing the co-doping ratio of Al2O3, La2O3 and SiO2, the sintering temperature of 95MCT ceramic can be lowered by 80°C, and the microwave dielectric properties can reach Qf=61856GHz and εr=19.84, which indicates the modified 95MCT ceramic have a great potential application in microwave communication devices. Based on this, we also designed a miniaturized microwave bandpass filter (BPF on modified 95MCT substrate. Through a full wave electromagnetic structure simulation, the results show that the center frequency of the BPF is 2.45GHz and the relative bandwidth is 4.09% with the insertion loss of less than 0.2dB in the whole bandpass.

Endoscopic Carpal Tunnel Release using a modified application technique of local anesthesia: safety and effectiveness

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Al-Khayat Jehad

2008-04-01

Full Text Available Abstract Background Local anesthesia is widely used for open carpal tunnel release. However, injection of local anesthesia as described by Altissimi and Mancini (1988 can interfere with endoscopic carpal tunnel release, by increasing the bulk of synovial layers and consequently result in worsening of the view. Purpose The purpose of this study was to evaluate the safety, efficacy using modified technique for application of local anesthesia. Methods 33 patients suffering from gradual increasing symptoms of carpal tunnel syndrome. The patients were also asked to evaluate the pain associated with injection as well as tourniquet during surgery using Visual Analogue Scale (VAS (ranging from 0 = no pain to 10 = maximum pain. Results One patient required additionally local anesthesia because of mild pain in the hand. The tourniquet was inflated for 13.00 (2.8 min. The pain score related to injection was 2.5 (0.8 and to tourniquet was 3.6 (0.9. Inflation of the tourniquet was well tolerated by all patients. Postoperative neurological sensory and motor deficits related to surgery and local blocks were not occurred. Conclusion Endoscopic release of the carpal tunnel syndrome in local anesthesia is effective, well tolerated and safe. This kind of application of local anesthesia did not reduce visibility.

Tramadol hydrochloride 75 mg/dexketoprofen 25 mg oral fixed-dose combination in moderate-to-severe acute pain: sustained analgesic effect over a 56-h period in the postoperative setting.

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Montero Matamala, A; Bertolotti, M; Contini, M P; Guerrero Bayón, C; Nizzardo, A; Paredes Lario, I; Pizà Vallespir, B; Scartoni, S; Tonini, G; Capriati, A; Pellacani, A

2017-06-01

Multimodal analgesia constitutes a common strategy in pain management. A tramadol hydrochloride 75 mg/dexketoprofen 25 mg oral fixed combination (TRAM/DKP 75 mg/25 mg) has been recently registered and released in Europe for the treatment of moderate-to-severe acute pain. This paper provides additional analyses on the results of two phase III clinical trials (DEX-TRA-04 and DEX-TRA-05) on postoperative pain to document its sustained effect. The analysis was applied to a modified intention-to-treat population (mITT, n = 933) of patients undergoing active treatment from the first dose, to assess the sustained effect of TRAM/DKP 75 mg/25 mg on pain intensity (PI-VAS 0-100) over 56 h from first drug intake. The superior analgesic effect of TRAM/DKP 75 mg/25 mg over 56 h in terms of difference in PI-VAS (mean [SE]) was shown for DEX-TRA-04 (-11.0 [0.55] over dexketoprofen 25 mg and -9.1 [0.55] over tramadol 100 mg, P ≤ 0.0001) and for DEX-TRA-05 (-10.4 [0.51] over dexketoprofen 25 mg and -8.3 [0.51] over tramadol 100 mg, P ≤ 0.0001). The statistical analysis performed on data coming from both studies confirms the superior sustained analgesia of TRAM/DKP 75 mg/25 mg over tramadol 100 mg and dexketoprofen 25 mg. These results are consistent with the previously published data obtained on the ITT population and strongly support the role of this oral fixed-dose combination in the treatment of moderate-to-severe acute pain. Copyright 2017 Clarivate Analytics.

The effect of scandium addition on microstructure and mechanical properties of Al–Si–Mg alloy: A multi-refinement modifier

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Xu, Cong, E-mail: xucong55555@gmail.com [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Xiao, Wenlong, E-mail: wlxiao@buaa.edu.cn [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China); Hanada, Shuji [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamagata, Hiroshi [Center for Advanced Die Engineering and Technology, Gifu University, 1-1 Yanagido, Gifu City, Gifu 501-1193 (Japan); Ma, Chaoli [Key Laboratory of Aerospace Advanced Materials and Performance of Ministry of Education, School of Material Science and Engineering, Beihang University, Beijing 100191 (China)

2015-12-15

Effect of scandium (Sc) additions on the microstructure, mechanical properties and fracture behavior of Al–Si–Mg casting alloy (F357) were systematically investigated. It was found that Sc addition caused a multi-refining efficiency on the microstructure of as-cast F357 alloy, including refinement of grains and secondary dendrite arm spacing (SDAS), modification of eutectic Si and harmless disposal of β-Al{sub 5}FeSi phase. Subsequent T6 heat treatment had further induced the complete spheroidization of eutectic Si and precipitation of fine secondary Al{sub 3}Sc dispersoids in the Sc modified alloys. Thus the mechanical properties, especially the ductility, were significantly enhanced by the addition of Sc combined with the heat treatment. The highest ultimate tensile strength, yield strength and elongation were achieved in 0.8 wt.% Sc modified F357 alloy combined with T6 heat treatment. Furthermore, fractographic examinations indicated that the ductile fracture mechanism served as a dominate role in the modified alloys due to the formation of fine, deep and uniformly distributed dimples. - Highlights: • Detailed characterization of the multi-refining microstructure of Sc modified F357 alloy was performed. • The multi-refinement was proposed to refine grain and SDAS, modify eutectic Si and β-phase. • Sc modifier combined with T6 treatment is effective in improving tensile properties. • Modification of eutectic Si in F357 alloy with Sc is consistent with the IIT mechanism.

Modified n-HA/PA66 scaffolds with chitosan coating for bone tissue engineering: cell stimulation and drug release.

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Zou, Qin; Li, Junfeng; Niu, Lulu; Zuo, Yi; Li, Jidong; Li, Yubao

2017-09-01

The dipping-drying procedure and cross-linking method were used to make drug-loaded chitosan (CS) coating on nano-hydroxyapatite/polyamide66 (nHA/PA66) composite porous scaffold, endowing the scaffold controlled drug release functionality. The prefabricated scaffold was immersed into an aqueous drug/CS solution in a vacuum condition and then crosslinked by vanillin. The structure, porosity, composition, compressive strength, swelling ratio, drug release and cytocompatibility of the pristine and coating scaffolds were investigated. After coating, the scaffold porosity and pore interconnection were slightly decreased. Cytocompatibility performance was observed through an in vitro experiment based on cell attachment and the MTT assay by MG63 cells which revealed positive cell viability and increasing proliferation over the 11-day period in vitro. The drug could effectively release from the coated scaffold in a controlled fashion and the release rate was sustained for a long period and highly dependent on coating swelling, suggesting the possibility of a controlled drug release. Our results demonstrate that the scaffold with drug-loaded crosslinked CS coating can be used as a simple technique to render the surfaces of synthetic scaffolds active, thus enabling them to be a promising high performance biomaterial in bone tissue engineering.

Effect of methylmercury on histamine release from rat mast cells

Energy Technology Data Exchange (ETDEWEB)

Graevskaya, Elizabeth E.; Rubin, Andrew B. [Moscow State University, Biological Faculty, Department of Biophysics, 119899, Vorobjovy Gory, Moscow (Russian Federation); Yasutake, Akira; Aramaki, Ryoji [National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008 (Japan)

2003-01-01

Methylmercury chloride (MeHgCl) is well known as a significant environmental hazard, particularly as a modulator of the immune system. As it is acknowledged that the critical effector cells in the host response participating in various biological responses are mast cells, we tried to define the possible contribution of mast cells in the development of methylmercury-evoked effects. We investigated the effects of methylmercury on the rat mast cell degranulation induced by non-immunological stimuli (the selective liberator of histamine, compound 48/80, and calcium ionophore A23187) both in vivo and in vitro. Using the cells prepared from methylmercury-intoxicated rats through a 5-day treatment of MeHgCl (10 mg/kg/day), we observed the suppression of calcium ionophore A23187- and 48/80-induced histamine release, which was enhanced with time after treatment. Similar suppression was observed in the ionophore-stimulated release, when cells were prepared from rat with a single treatment of MeHgCl (20 mg/kg). It should be noted that when cells from the control rat were pre-incubated with methylmercury in vitro at a 10{sup -8} M concentration for 10 min, A23187 and compound 48/80-stimulated histamine release was significantly enhanced. However, when the pre-incubation period was prolonged to 30 min, the release was suppressed. An increase in the methylmercury concentration to 10{sup -6} M also suppressed the histamine release. These results show that methylmercury treatment can modify mast cell function depending on concentration and time, and might provide an insight into the role of mast cells in the development of methylmercury-stimulated effects. (orig.)

Scientific and Regulatory Considerations in Solid Oral Modified Release Drug Product Development.

Science.gov (United States)

Li, Min; Sander, Sanna; Duan, John; Rosencrance, Susan; Miksinski, Sarah Pope; Yu, Lawrence; Seo, Paul; Rege, Bhagwant

2016-11-01

This review presents scientific and regulatory considerations for the development of solid oral modified release (MR) drug products. It includes a rationale for patient-focused development based on Quality-by-Design (QbD) principles. Product and process understanding of MR products includes identification and risk-based evaluation of critical material attributes (CMAs), critical process parameters (CPPs), and their impact on critical quality attributes (CQAs) that affect the clinical performance. The use of various biopharmaceutics tools that link the CQAs to a predictable and reproducible clinical performance for patient benefit is emphasized. Product and process understanding lead to a more comprehensive control strategy that can maintain product quality through the shelf life and the lifecycle of the drug product. The overall goal is to develop MR products that consistently meet the clinical objectives while mitigating the risks to patients by reducing the probability and increasing the detectability of CQA failures.

Preparation of venlafaxine hydrochloride sustained-release tablets

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GUO Lingling

2013-08-01

Full Text Available To prepare venlafxine hydrochloride sustained-release tablets.Hydroxypropylmethyl cellulose(HPMC and methyl cellulose(MC were used as main materials to prepare sustained-release tablets of velafaxine hydrochloride and the influence of important factors on in vitro release curves of venlafaxine hydrochloride sustained-release tablets was investigated.Results:The optimal prescription included 100 mg HPMC,25 mg MC,and 2.5% glidant in one tablet prepared with 30kN.The tablets were prepared with the method of wet granulation by NO.16 mesh sieve.The tablets exhibited good sustained-release property in phosphate buffered solution (pH=6.8.The as-prepared venlafxine hydrochloride sustained-release tablets have good sustained-release property.

Modified gum Arabic hydrogels as matrices for controlled release of curcumin supramolecular complexes; Hidrogeis de goma arabica modificada como matrizes para libertacao controlada de complexos supramoleculares de curcumina

Energy Technology Data Exchange (ETDEWEB)

Gerola, Adriana P.; Silva, Danielle C., E-mail: avalente@ci.uc.pt [Department of Chemistry, University of Coimbra, Coimbra (Portugal); Rubira, Adley F.; Muniz, Edvani C. [Universidade Estadual de Maringa (GMPC/UEM), PR (Brazil). Grupo de Materiais Polimericos e Compositos; Jesus, Sandra; Borges, Olga [Faculty of Pharmacy, University of Coimbra, Coimbra (Portugal)

2015-07-01

Modified gum Arabic (GA) hydrogels show a pH-responsive behavior making them excellent matrices to be used for oral administration of drugs. Our goal is to study the behavior of those matrices in simulated gastric and intestinal fluids. In this work we will present how the methacrylation degree of GA, by using glycidyl methacrylate, can affect the properties of these hydrogels for controlled release. The drug used in this work is the curcumin (Cur). Cur is associated with numerous pharmacological activities, but their application is limited by the low water solubility. We will present some studies involving the formation of host-guest complexes between Cur and natural cyclodextrins. Both modified GA and hydrogels were characterized by different techniques. The kinetics release of Cur complex-containing modified GA hydrogels was studied to have an insight on the release mechanism and rate constants. Toxicity studies on undifferentiated and differentiated Caco-2 were also carried out. (author)

Mesoporous carbon-coated LiFePO4 nanocrystals co-modified with graphene and Mg2+ doping as superior cathode materials for lithium ion batteries.

Science.gov (United States)

Wang, Bo; Xu, Binghui; Liu, Tiefeng; Liu, Peng; Guo, Chenfeng; Wang, Shuo; Wang, Qiuming; Xiong, Zhigang; Wang, Dianlong; Zhao, X S

2014-01-21

In this work, mesoporous carbon-coated LiFePO4 nanocrystals further co-modified with graphene and Mg(2+) doping (G/LFMP) were synthesized by a modified rheological phase method to improve the speed of lithium storage as well as cycling stability. The mesoporous structure of LiFePO4 nanocrystals was designed and realized by introducing the bead milling technique, which assisted in forming sucrose-pyrolytic carbon nanoparticles as the template for generating mesopores. For comparison purposes, samples modified only with graphene (G/LFP) or Mg(2+) doping (LFMP) as well as pure LiFePO4 (LFP) were also prepared and investigated. Microscopic observation and nitrogen sorption analysis have revealed the mesoporous morphologies of the as-prepared composites. X-ray diffraction (XRD) and Rietveld refinement data demonstrated that the Mg-doped LiFePO4 is a single olivine-type phase and well crystallized with shortened Fe-O and P-O bonds and a lengthened Li-O bond, resulting in an enhanced Li(+) diffusion velocity. Electrochemical properties have also been investigated after assembling coin cells with the as-prepared composites as the cathode active materials. Remarkably, the G/LFMP composite has exhibited the best electrochemical properties, including fast lithium storage performance and excellent cycle stability. That is because the modification of graphene provided active sites for nuclei, restricted the in situ crystallite growth, increased the electronic conductivity and reduced the interface reaction current density, while, Mg(2+) doping improved the intrinsically electronic and ionic transfer properties of LFP crystals. Moreover, in the G/LFMP composite, the graphene component plays the role of "cushion" as it could quickly realize capacity response, buffering the impact to LFMP under the conditions of high-rate charging or discharging, which results in a pre-eminent rate capability and cycling stability.

In vitro degradation and cytotoxicity of Mg/Ca composites produced by powder metallurgy.

Science.gov (United States)

Zheng, Y F; Gu, X N; Xi, Y L; Chai, D L

2010-05-01

Mg/Ca (1 wt.%, 5 wt.%, 10 wt.% Ca) composites were prepared from pure magnesium and calcium powders using the powder metallurgy method, aiming to enlarge the addition of Ca content without the formation of Mg(2)Ca. The microstructures, mechanical properties and cytotoxicities of Mg/Ca composite samples were investigated. The corrosion of Mg/Ca composites in Dulbecco's modified Eagle's medium (DMEM) for various immersion intervals was studied by electrochemical impedance spectroscopy measurements and environmental scanning electron microscope, with the concentrations of released Mg and Ca ions in DMEM for various immersion time intervals being measured. It was shown that the main constitutional phases were Mg and Ca, which were uniformly distributed in the Mg matrix. The ultimate tensile strength (UTS) and elongation of experimental composites decreased with increasing Ca content, and the UTS of Mg/1Ca composite was comparable with that of as-extruded Mg-1Ca alloy. The corrosion potential increased with increasing Ca content, whereas the current density and the impedance decreased. It was found that the protective surface film formed quickly at the initial immersion stage. With increasing immersion time, the surface film became compact, and the corrosion rate of Mg/Ca composites slowed down. The surface film consisted mainly of CaCO(3), MgCO(3)x3H(2)O, HA and Mg(OH)(2) after 72 h immersion in DMEM. Mg/1Ca and Mg/5Ca composite extracts had no significant toxicity (p>0.05) to L-929 cells, whereas Mg/10Ca composite extract induced approximately 40% reduced cell viability. Copyright (c) 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Microstructure-modified biodegradable magnesium alloy for promoting cytocompatibility and wound healing in vitro.

Science.gov (United States)

Lin, Da-Jun; Hung, Fei-Yi; Yeh, Ming-Long; Lui, Truan-Sheng

2015-10-01

The microstructure of biomedical magnesium alloys has great influence on anti-corrosion performance and biocompatibility. In practical application and for the purpose of microstructure modification, heat treatments were chosen to provide widely varying microstructures. The aim of the present work was to investigate the influence of the microstructural parameters of an Al-free Mg-Zn-Zr alloy (ZK60), and the corresponding heat-treatment-modified microstructures on the resultant corrosion resistance and biological performance. Significant enhancement in corrosion resistance was obtained in Al-free Mg-Zn-Zr alloy (ZK60) through 400 °C solid-solution heat treatment. It was found that the optimal condition of solid-solution treatment homogenized the matrix and eliminated internal defects; after which, the problem of unfavorable corrosion behavior was improved. Further, it was also found that the Mg ion-release concentration from the modified ZK60 significantly induced the cellular activity of fibroblast cells, revealing in high viability value and migration ability. The experimental evidence suggests that this system can further accelerate wound healing. From the perspective of specific biomedical applications, this research result suggests that the heat treatment should be applied in order to improve the biological performance.

Modified local diatomite as potential functional drug carrier--A model study for diclofenac sodium.

Science.gov (United States)

Janićijević, Jelena; Krajišnik, Danina; Čalija, Bojan; Vasiljević, Bojana Nedić; Dobričić, Vladimir; Daković, Aleksandra; Antonijević, Milan D; Milić, Jela

2015-12-30

Diatomite makes a promising candidate for a drug carrier because of its high porosity, large surface area, modifiable surface chemistry and biocompatibility. Herein, refined diatomite from Kolubara coal basin, which complied with the pharmacopoeial requirements for heavy metals content and microbiological quality, was used as a starting material. Inorganic modification of the starting material was performed through a simple, one-step procedure. Significant increase in adsorbent loading with diclofenac sodium (DS) was achieved after the modification process (∼373mg/g) which enabled the preparation of comprimates containing therapeutic dose of the adsorbed drug. Adsorption of DS onto modified diatomite resulted in the alteration of the drug's XRD pattern and FTIR spectrum. In vitro drug release studies in phosphate buffer pH 7.5 demonstrated prolonged DS release over 8h from comprimates containing DS adsorbed on modified diatomite (up to 37% after 8h) and those containing physical mixture of the same composition (up to 45% after 8h). The results of in vivo toxicity testing on mice pointed on potential safety of both unmodified (starting) and modified diatomite. All these findings favor the application of diatomite as a potential functional drug carrier. Copyright © 2015 Elsevier B.V. All rights reserved.

In Vitro Inhibition of Histamine Release Behavior of Cetirizine Intercalated into Zn/Al- and Mg/Al-Layered Double Hydroxides

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Muhammad Nazrul Hakim

2012-05-01

Full Text Available The intercalation of cetirizine into two types of layered double hydroxides, Zn/Al and Mg/Al, has been investigated by the ion exchange method to form CTZAN and CTMAN nanocomposites, respectively. The basal spacing of the nanocomposites were expanded to 31.9 Å for CTZAN and 31.2 Å for CTMAN, suggesting that cetirizine anion was intercalated into Layered double hydroxides (LDHs and arranged in a tilted bilayer fashion. A Fourier transform infrared spectroscopy (FTIR study supported the formation of both the nanocomposites, and the intercalated cetirizine is thermally more stable than its counterpart in free state. The loading of cetirizine in the nanocomposite was estimated to be about 57.2% for CTZAN and 60.7% CTMAN. The cetirizine release from the nanocomposites show sustained release manner and the release rate of cetirizine from CTZAN and CTMAN nanocomposites at pH 7.4 is remarkably lower than that at pH 4.8, presumably due to the different release mechanism. The inhibition of histamine release from RBL2H3 cells by the free cetirizine is higher than the intercalated cetirizine both in CTZAN and CTMAN nanocomposites. The viability in human Chang liver cells at 1000 μg/mL for CTZAN and CTMAN nanocomposites are 74.5 and 91.9%, respectively.

Single- and multiple-dose pharmacokinetics of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (MNK-155 compared with immediate-release hydrocodone bitartrate/ibuprofen and immediate-release tramadol HCl/acetaminophen

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Devarakonda K

2015-09-01

Full Text Available Krishna Devarakonda,1 Kenneth Kostenbader,2 Michael J Giuliani,3 Jim L Young41Department of Clinical Pharmacology, Mallinckrodt Pharmaceuticals, 2Mallinckrodt Pharmaceuticals, 3Research and Development, Mallinckrodt Pharmaceuticals, 4Department of Clinical Affairs and Program Management, Mallinckrodt Pharmaceuticals, Hazelwood, MO, USAObjective: To characterize the single-dose and steady-state pharmacokinetics (PK of biphasic immediate-release/extended-release hydrocodone bitartrate/acetaminophen (IR/ER HB/APAP, IR HB/ibuprofen, and IR tramadol HCl/APAP.Methods: In this single-center, open-label, randomized, four-period crossover study, healthy participants received four treatments under fasted conditions: 1 a single dose of two IR/ER HB/APAP 7.5/325 mg tablets (15/650 mg total dose on day 1, followed by two tablets every 12 hours (q12h beginning on day 3; 2 a single dose of IR HB/ibuprofen 15/400 mg (divided as one 7.5/200 mg tablet at hour 0 and 6, followed by one tablet every 6 hours (q6h beginning on day 3; 3 a single dose of IR tramadol HCl/APAP 75/650 mg (divided as one 37.5/325 mg tablet at hour 0 and 6, followed by one tablet q6h beginning on day 3; and 4 a single dose of three IR/ER HB/APAP 7.5/325 mg tablets (22.5/975 mg total dose on day 1, a three-tablet initial dose at 48 hours followed by two-tablet doses q12h beginning on day 3. Hydrocodone and APAP single-dose and steady-state PK were assessed. Adverse events were monitored.Results: The PK analysis was carried out on 29 of 48 enrolled participants who completed all treatment periods. Single-dose hydrocodone exposure was similar for IR/ER HB/APAP 22.5/975 mg and IR HB/ibuprofen 15/400 mg; time to maximum observed plasma concentration was shorter and half-life was longer for IR/ER HB/APAP (22.5/975 mg and 15/650 mg vs IR HB/ibuprofen. Single-dose APAP exposure was similar for IR/ER HB/APAP 15/650 mg and IR tramadol HCl/APAP 75/650 mg. Steady-state hydrocodone and APAP exposures

Study of the structural and electrical behavior of Bi(Mg,TiO3 modified (Ba,CaTiO3 ceramics

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Md. Kashif Shamim

2016-12-01

Full Text Available The ability of BaTiO3 to form solid solutions with different dopants (both iso- and aliovalent makes it versatile for various applications. In the present study, (Ba,CaTiO3 (BCT is modified with Bi(MgTiO3 (BMT in search for new lead-free ferroelectric material and improve their properties. For this purpose, BCT acts as a main base material and BMT acts as a modifier to fabricate a multifunctional material. In this study, we report the structural and electrical properties of lead free piezo-ceramics (1−x(Ba0.8Ca0.2TiO3–xBi(Mg0.5Ti0.5O3 with x=0.2, 0.4, 0.5 prepared by solid-state sintering technique. Single perovskite phase with tetragonal structure is obtained for all the compositions, which is reconfirmed by the Raman Spectroscopic study. Dielectric study confirm the temperature stable behavior of the dielectric permittivity values above 300∘C. The dielectric constant value decreases with increase in BMT doping content. Impedance Spectroscopic study confirms non-Debye type dielectric relaxation in the specimen. The Nyquist plot and conductivity studies show the negative temperature coefficient of resistance behavior (NTCR of the samples.

Evaluation of magnesium ions release, biocorrosion, and hemocompatibility of MAO/PLLA-modified magnesium alloy WE42.

Science.gov (United States)

Lu, Ping; Cao, Lu; Liu, Yin; Xu, Xinhua; Wu, Xiangfeng

2011-01-01

Magnesium alloys may potentially be applied as biodegradable metallic materials in cardiovascular stent. However, the high corrosion rate hinders its clinical application. In this study, a new approach was adopted to control the corrosion rate by fabricating a biocompatible micro-arc oxidation/poly-L-lactic acid (MAO/PLLA) composite coating on the magnesium alloy WE42 substrate and the biocompatibility of the modified samples was investigated. The scanning electronic microscope (SEM) images were used to demonstrate the morphology of the samples before and after being submerged in hanks solution for 4 weeks. The degradation was evaluated through the magnesium ions release rate and electrochemical impedance spectroscopy (EIS) test. The biocompatibility of the samples was demonstrated by coagulation time and hemolysis behavior. The result shows that the poly-L-lactic acid (PLLA) effectively improved the corrosion resistance by sealing the microcracks and microholes on the surface of the MAO coating. The modified samples had good compatibility. © 2010 Wiley Periodicals, Inc.

Mechanism of the beneficial effects of ATP-MgCl2 following trauma-hemorrhage and resuscitation: downregulation of inflammatory cytokine (TNF, IL-6) release.

Science.gov (United States)

Wang, P; Ba, Z F; Morrison, M H; Ayala, A; Dean, R E; Chaudry, I H

1992-04-01

Although ATP-MgCl2 improves hepatocellular function in a nonheparinized model of trauma-hemorrhage and crystalloid resuscitation, it remains unknown whether the beneficial effects of this agent are due to downregulation of the release of the inflammatory cytokines, tumor necrosis factor (TNF), and interleukin-6 (IL-6) under those conditions. To study this, rats underwent a 5-cm laparotomy (i.e., trauma induced) and were bled to and maintained at a mean arterial pressure of 40 mm Hg until 40% of maximum bleedout volume was returned in the form of Ringer's lactate (RL). The animals were then resuscitated with four times the volume of shed blood with RL over 60 min. ATP-MgCl2 (50 mumoles/kg body weight each) or an equivalent volume of normal saline was infused intravenously for 95 min. This infusion was started during the last 15 min of RL resuscitation. Plasma levels of TNF and IL-6 were measured at 1.5 hr after the completion of resuscitation by cytokine-dependent cellular assays. Hepatic blood flow was determined by in vivo indocyanine green clearance (corrected by hepatic extraction ratio for indocyanine green), radioactive microspheres, and [3H]-galactose clearance techniques. The results indicate that the levels of circulating TNF and IL-6 increased significantly in the hemorrhaged-resuscitated animals. ATP-MgCl2 treatment, however, markedly decreased the synthesis and/or release of these cytokines to levels similar to the sham group. The markedly decreased hepatic blood flow (as determined by three different methods) and hepatic extraction ratio for indocyanine green were also restored by ATP-MgCl2 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Formation and Corrosion Resistance of Mg-Al Hydrotalcite Film on Mg-Gd-Zn Alloy

Science.gov (United States)

Ba, Z. X.; Dong, Q. S.; Kong, S. X.; Zhang, X. B.; Xue, Y. J.; Chen, Y. J.

2017-06-01

An environment-friendly technique for depositing a Mg-Al hydrotalcite (HT) (Mg6Al2(OH)16-CO3ṡ4H2O) conversion film was developed to protect the Mg-Gd-Zn alloy from corrosion. The morphology and chemical compositions of the film were analyzed by scanning electronic microscope (SEM) equipped with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and Raman spectroscopy (RS), respectively. The electrochemical test and hydrogen evolution test were employed to evaluate the biocorrosion behavior of Mg-Gd-Zn alloy coated with the Mg-Al HT film in the simulated body fluid (SBF). It was found that the formation of Mg-Al HT film was a transition from amorphous precursor to a crystalline HT structure. The HT film can effectively improve the corrosion resistance of magnesium alloy. It indicates that the process provides a promising approach to modify Mg-Gd-Zn alloy.

Preparation of Zn(BH4)2 and diborane and hydrogen release properties of Zn(BH4)2+xMgH2 (x=1, 5, 10, and 15)

Science.gov (United States)

Kwak, Young Jun; Kwon, Sung Nam; Song, Myoung Youp

2015-09-01

Zn(BH4)2 was prepared by milling ZnCl2 and NaBH4 in a planetary ball mill under Ar atmosphere, and Zn(BH4)2+xMgH2 (x=1, 5, 10, and 15) samples were prepared. Diborane (B2H6) and hydrogen release characteristics of the Zn(BH4)2 and Zn(BH4)2+xMgH2 samples were studied. The samples synthesized by milling ZnCl2 and NaBH4 contained Zn(BH4)2 and NaCl, together with small amounts of ZnCl2 and NaBH4. We designated these samples as Zn(BH4)2(+NaCl). The weight loss up to 400 °C of the Zn(BH4)2(+NaCl) sample synthesized by milling 4 h was 11.2 wt%. FT-IR analysis showed that Zn(BH4)2 was formed in the Zn(BH4)2(+NaCl) samples. MgH2 was also milled in a planetary ball mill, and mixed with the Zn(BH4)2(+NaCl) synthesized by milling for 4 h in a mortar and pestle. The weight loss up to 400 °C of Zn(BH4)2(+NaCl)+MgH2 was 8.2 wt%, corresponding to the weight % of diborane and hydrogen released from the Zn(BH4)2(+NaCl)+MgH2 sample, with respect to the sample weight. DTA results of Zn(BH4)2(+NaCl)+xMgH2 showed that the decomposition peak of Zn(BH4)2 was at about 61 °C, and that of MgH2 was at about 370-389 °C.

Development of Bilayer Tablets with Modified Release of Selected Incompatible Drugs.

Science.gov (United States)

Dhiman, Neha; Awasthi, Rajendra; Jindal, Shammy; Khatri, Smriti; Dua, Kamal

2016-01-01

The oral route is considered to be the most convenient and commonly-employed route for drug delivery. When two incompatible drugs need to be administered at the same time and in a single formulation, bilayer tablets are the most appropriate dosage form to administer such incompatible drugs in a single dose. The aim of the present investigation was to develop bilayered tablets of two incompatible drugs; telmisartan and simvastatin. The bilayer tablets were prepared containing telmisartan in a conventional release layer using croscarmellose sodium as a super disintegrant and simvastatin in a slow-release layer using HPMC K15M, Carbopol 934P and PVP K 30 as matrix forming polymers. The tablets were evaluated for various physical properties, drug-excipient interactions using FTIR spectroscopy and in vitro drug release using 0.1M HCl (pH 1.2) for the first hour and phosphate buffer (pH 6.8) for the remaining period of time. The release kinetics of simvastatin from the slow release layer were evaluated using the zero order, first order, Higuchi equation and Peppas equation. All the physical parameters (such as hardness, thickness, disintegration, friability and layer separation tests) were found to be satisfactory. The FTIR studies indicated the absence of interactions between the components within the individual layers, suggesting drug-excipient compatibility in all the formulations. No drug release from the slow-release layer was observed during the first hour of the dissolution study in 0.1M HCl. The release-controlling polymers had a significant effect on the release of simvastatin from the slow-release layer. Thus, the formulated bilayer tablets avoided incompatibility issues and proved the conventional release of telmisartan (85% in 45 min) and slow release of simvastatin (80% in 8 h). Stable and compatible bilayer tablets containing telmisartan and simvastatin were developed with better patient compliance as an alternative to existing conventional dosage forms.

Redox regulation of calcium release in skeletal and cardiac muscle

Directory of Open Access Journals (Sweden)

CECILIA HIDALGO

2002-01-01

Full Text Available In skeletal and cardiac muscle cells, specific isoforms of the Ryanodine receptor channels mediate Ca2+ release from the sarcoplasmic reticulum. These channels are highly susceptible to redox modifications, which regulate channel activity. In this work, we studied the effects of Ca2+ (endogenous agonist and Mg2+ (endogenous inhibitor on the kinetics of Ca2+ release from sarcoplasmic reticulum vesicles isolated from skeletal or cardiac mammalian muscle. Native skeletal vesicles exhibited maximal stimulation of release kinetics by 10-20 µM [Ca2+], whereas in native cardiac vesicles, maximal stimulation of release required only 1 µM [Ca2+]. In 10 µM [Ca2+], free [Mg2+] < 0.1 mM produced marked inhibition of release from skeletal vesicles but free [Mg2+] ­ 0.8 mM did not affect release from cardiac vesicles. Incubation of skeletal or cardiac vesicles with the oxidant thimerosal increased their susceptibility to stimulation by Ca2+ and decreased the inhibitory effect of Mg2+ in skeletal vesicles. Sulfhydryl-reducing agents fully reversed the effects of thimerosal. The endogenous redox species, glutathione disulfide and S-nitrosoglutathione, also stimulated release from skeletal sarcoplasmic reticulum vesicles. In 10 µM [Ca2+], 35S-nitrosoglutathione labeled a protein fraction enriched in release channels through S-glutathiolation. Free [Mg2+] 1 mM or decreasing free [Ca2+] to the nM range prevented this reaction. Possible physiological and pathological consequences of redox modification of release channels on Ca2+ signaling in heart and muscle cells are discussed

Biocompatible hyperbranched polyglycerol modified β-cyclodextrin derivatives for docetaxel delivery

Energy Technology Data Exchange (ETDEWEB)

Xu, Zejun; Zhang, Yi; Hu, Qian; Tang, Qiao [Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, 510632 (China); Xu, Jiake [The School of Pathology and Laboratory Medicine, University of Western Australia, Perth (Australia); Wu, Jianping; Kirk, Thomas Brett [3D Imaging and Bioengineering Laboratory, Department of Mechanical Engineering, Curtin University (Australia); Ma, Dong, E-mail: tmadong@jnu.edu.cn [Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, 510632 (China); Xue, Wei, E-mail: weixue_jnu@hotmail.com [Key Laboratory of Biomaterials of Guangdong Higher Education Institutes, Department of Biomedical Engineering, Jinan University, Guangzhou, 510632 (China)

2017-02-01

The development of biocompatible vector for hydrophobic drug delivery remains a longstanding issue in cancer therapy. We design and synthesis a drug delivery system based on HPG modified β-CD (β-CD-HPG) by conjugating HPG branches onto β-CD core and its structure was confirmed by NMR, FTIR, GPC and solubility. In vitro biocompatibility tests showed that HPG modification significantly improved red blood cells morphology alteration and hemolysis cause by β-CD and β-CD-HPG displayed cell safety apparently in a wide range of 0.01–1 mg/mL. An anti-cancer drug, docetaxel, was effectively encapsulated into β-CD-HPG which was confirmed by DSC analysis. This copolymer could form nanoparticles with small size (< 200 nm) and exhibited better DTX loading capacity and controlled release kinetics without initial burst release behavior compared with β-CD. Furthermore, antitumor assay in vitro show that β-CD-HPG/DTX effectively inhibited proliferation of human breast adenocarcinoma cells. Therefore, β-CD-HPG/DTX exhibit great potential for cancer chemotherapy. - Highlights: • A new drug delivery system based on HPG modified β-CD (β-CD-HPG) has been synthesized. • It showed excellent cytocompatibility, hemocompatibility and docetaxel delivery ability. • It could effectively inhibited proliferation of human breast adenocarcinoma cells.

Influence of Sintering Temperature on Pore Structure and Electrical properties of Technologically Modified MgO-Al2O3 Ceramics

Directory of Open Access Journals (Sweden)

Halyna Klym

2015-03-01

Full Text Available Technologically modified spinel ceramics are prepared from Al2O3 and 4MgCO3×Mg(OH2×5H2O powders at 1200, 1300 and 1400 oC. The influence of sintering temperature on porous structure and exploitation properties of obtained humidity-sensitive MgO-Al2O3 ceramics are studied. It is shown that increasing of preparing temperature from 1200 to 1400 oC result in transformation of pore size distribution in ceramics from tri- to bi-modal including the open macro- and mesopores with sizes from tem to hundreds nm and nanopores until to a few nm. The studied ceramic elements with electrical resistances ~ 10-2-102 MОhm are high humidity sensitive in the region of 30-95 % with minimal hysteresis in adsorption-desorption cycles. It is established that increasing of humidity sensitivity in ceramics are related to achievement near to optimum pore size distribution and quantity of pores in the all regions. Prolonged degradation transformation in ceramics at higher temperature and relative humidity result in lose sensitivity up to 40-50 %.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5189

Dual inhibitory action of enadoline (CI977) on release of amino acids in the rat hippocampus.

Science.gov (United States)

Millan, M H; Chapman, A G; Meldrum, B S

1995-06-06

The effect of the kappa-opioid receptor agonist enadoline (CI977, (5R)-(5 alpha,7 alpha,8 beta)-N-methyl-N-[7-(1-pyrrilidinyl)-1-oxaspiro [4,5]dec-8-yl-4-benzofuranacetamide monohydrochloride), on the release of amino acids was studied in the hippocampus of freely moving rats. K+, 100 mM, or veratrine, 100 microM, were applied for 10 min via the dialysis probe, either alone (control groups) or together with CI977 (after a 10 min pretreatment with CI977 in the perfusion medium). To test the specificity of the response to CI977, nor-binaltorphimine, a selective kappa-opioid receptor antagonist, was delivered together with CI977 in two groups of animals. To test the effect of systemic injection, CI977 was given subcutaneously 30 min prior to either stimulus. K(+)-induced release of glutamate and aspartate was significantly reduced by CI977, 2.5 mM; release of gamma-aminobutyric acid (GABA) was reduced by 250 microM CI977 in the probe. The effect of CI977 on release of glutamate and aspartate, but not of GABA, was reversed by nor-binaltorphimine (45 microM). Systemic treatment with CI977, 1 or 10 mg/kg, did not reduce K(+)-induced release of glutamate. Veratrine-induced release of aspartate and glutamate was significantly inhibited by 25 microM and release of GABA by 250 microM CI977 in the probe, and this effect was not modified by nor-binaltorphimine (58 microM). Systemic injection of CI977 1 mg/kg significantly reduced veratrine-induced release of glutamate. These results indicate that CI977 regulates release of amino acids by two independent mechanisms.(ABSTRACT TRUNCATED AT 250 WORDS)

Impact of food, alcohol and pH on modified-release hydrocortisone developed to treat congenital adrenal hyperplasia.

Science.gov (United States)

Karunasena, Nayananjani; Margetson, Daniel N; Neal, Greg; Whitaker, Martin J; Ross, Richard Jm

2017-04-01

We developed a modified-release hydrocortisone, Chronocort, to replace the cortisol rhythm in patients with congenital adrenal hyperplasia. Food, alcohol and pH affect drug absorption, and it is important to assess their impact when replicating a physiological rhythm. In vitro dissolution to study impact of alcohol and pH on Chronocort. A phase 1, three-period, cross over study in 18 volunteers to assess the impact of food on Chronocort and to compare bioavailability to immediate-release hydrocortisone. In vitro dissolution of Chronocort was not affected by gastrointestinal pH up to 6.0 nor by an alcohol content up to 20% v/v. Food delayed and reduced the rate of absorption of Chronocort as reflected by a longer T max (fed vs fasted: 6.75 h vs 4.5 h, P  = 0005) and lower C max (549.49 nmol/L vs 708.46 nmol/L, ratio 77% with CI 71-85). Cortisol exposure was similar in fed and fasted state: Geo LSmean ratio (CI) AUC 0t for fed/fasted was 108.33% (102.30-114.72%). Cortisol exposure was higher for Chronocort compared to immediate-release hydrocortisone: Geo LSmean ratios (CI) 118.83% (111.58-126.54%); however, derived free cortisol showed cortisol exposure CIs were within 80.0-125.0%: Geo LSmean ratio (CI) for AUC 0t 112.73% (105.33-120.65%). Gastric pH ≤6.0 and alcohol do not affect hydrocortisone release from Chronocort. Food delays Chronocort absorption, but cortisol exposure is similar in the fasted and fed state and exposure as assessed by free cortisol is similar between Chronocort and immediate-release hydrocortisone. © 2017 The authors.

Biscuits with No Added Sugar Containing Stevia, Coffee Fibre and Fructooligosaccharides Modifies α-Glucosidase Activity and the Release of GLP-1 from HuTu-80 Cells and Serotonin from Caco-2 Cells after In Vitro Digestion.

Science.gov (United States)

Martinez-Saez, Nuria; Hochkogler, Christina Maria; Somoza, Veronika; Del Castillo, Maria Dolores

2017-07-04

This study assessed the in vitro effects of the bioaccessible food components released during the simulated human digestion of a coffee fibre-containing biscuit (CFB) on α-glucosidase activity, antioxidant capacity and satiety hormones. Digest of CFB presented a significantly ( p < 0.05) lower amount of sugar (68.6 mg/g) and a higher antioxidant capacity (15.1 mg chlorogenic acid eq./g) than that of a sucrose-containing biscuit (SCB). The CFB significantly reduced ( p < 0.05) α-glucosidase activity (IC50 = 3.3 mg/mL) compared to the SCB (IC50 = 6.2 mg/mL). Serotonin and glucagon-like peptide-1 (GLP-1) release by differentiated Caco-2 and HuTu-80 cells, respectively, was stimulated by the CFB (355% at a concentration of 0.5 mg/mL and 278% at a concentration of 0.05 mg/mL) to the same order of magnitude as those of the SCB. To summarize, the CFB was demonstrated to reduce monosaccharide bioaccessibility, to inhibit a diabetes-related digestive enzyme, and to improve the release of satiety hormones.

Dehydration and hydration behavior of metal-salt-modified materials for chemical heat pumps

International Nuclear Information System (INIS)

Ishitobi, Hirokazu; Uruma, Keirei; Takeuchi, Masato; Ryu, Junichi; Kato, Yukitaka

2013-01-01

Lithium chloride (LiCl) modified magnesium hydroxide (Mg(OH) 2 ) is a potential new material for chemical heat pumps. However, there is insufficient information concerning its dehydration and hydration behavior. In this study, the dehydration and hydration reactions, corresponding to the heat storage and the heat output operations, respectively, of authentic Mg(OH) 2 and LiCl-modified Mg(OH) 2 were investigated by thermogravimetric methods and near infrared spectroscopy. The dehydration of authentic Mg(OH) 2 proceeded as a one-step reaction. In contrast, the dehydration of LiCl-modified Mg(OH) 2 occurred in two steps. The dehydration reaction rates were increased by LiCl modification of the Mg(OH) 2 surface, while the activation energy for the first-order dehydration reaction was lowered. The mechanism for the hydration reaction of magnesium oxide (MgO) was different to that for the hydration of LiCl-modified MgO. This difference was explained by the effect of the LiCl on the MgO particle surface. - Highlights: ► LiCl-modified Mg(OH) 2 is a candidate material for chemical heat pumps. ► The dehydration reaction of LiCl-modified Mg(OH) 2 is a two-step reaction. ► The dehydration reaction of Mg(OH) 2 was enhanced by LiCl modification. ► The hydration mechanisms of authentic MgO and LiCl-modified MgO were different.

Interlayer exchange coupling, dipolar coupling and magnetoresistance in Fe/MgO/Fe trilayers with a subnanometer MgO barrier

Energy Technology Data Exchange (ETDEWEB)

Kozioł-Rachwał, A. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); National Institute of Advanced Industrial Science and Technology, Spintronics Research Center, Tsukuba, Ibaraki 305-8568 (Japan); Skowroński, W.; Frankowski, M. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Chęciński, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Ziętek, S.; Rzeszut, P. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Ślęzak, M.; Matlak, K.; Ślęzak, T. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Stobiecki, T. [AGH University of Science and Technology, Department of Electronics, al. Mickiewicza 30, 30-059 Kraków (Poland); Korecki, J. [AGH University of Science and Technology, Faculty of Physics and Applied Computer Science, al. Mickiewicza 30, 30-059 Kraków (Poland); Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków (Poland)

2017-02-15

Fe/MgO/Fe trilayers with a subnanometer MgO tunnel barrier were grown by molecular beam epitaxy. Longitudinal magnetooptic Kerr effect measurements confirmed the existence of the antiferromagnetic interlayer exchange coupling (IEC) between the Fe layers for 2 ÅMgO}<6 Å. The coupling was enhanced for the trilayer grown on a homoepitaxial MgO buffer layer, and its IEC constant was estimated to be −3.3 erg/cm{sup 2} at a MgO thickness of 2.7 Å. After magnetic characterization, the sample was patterned into circular-shaped pillars with diameters ranging from 200 nm to 520 nm. We showed that the dipolar coupling that appeared after the nanofabrication process modified the effective coupling between layers, and we determined dependence of the dipolar coupling on the pillar diameter. Finally, magnetoresistance (MR) was measured as a function of MgO thickness (d{sub MgO}), and a non-zero MR was found for the MgO as thin as 3.4 Å. Extrapolation of the MR (d{sub MgO}) dependence to MR=0 allowed us to determine the length of the pinholes in our sample, which was estimated to be (3.2±0.5) Å. - Highlights: • Strong antiferromagnetic (AFM) interlayer exchange coupling (IEC) between Fe layers in Fe/MgO/Fe. • After nanofabrication the effective AFM IEC is enhanced due to the dipolar coupling. • The dipolar coupling that appeared after the nanofabrication process modified the effective coupling between layers. • Non-zero magnetoresistance values registered for the Fe/MgO/Fe trilayers with the MgO spacers as thin as 3.4 Å.

Doxycycline-loaded nanotube-modified adhesives inhibit MMP in a dose-dependent fashion.

Science.gov (United States)

Palasuk, Jadesada; Windsor, L Jack; Platt, Jeffrey A; Lvov, Yuri; Geraldeli, Saulo; Bottino, Marco C

2018-04-01

This article evaluated the drug loading, release kinetics, and matrix metalloproteinase (MMP) inhibition of doxycycline (DOX) released from DOX-loaded nanotube-modified adhesives. DOX was chosen as the model drug, since it is the only MMP inhibitor approved by the U.S. Food and Drug Administration. Drug loading into the nanotubes was accomplished using DOX solution at distinct concentrations. Increased concentrations of DOX significantly improved the amount of loaded DOX. The modified adhesives were fabricated by incorporating DOX-loaded nanotubes into the adhesive resin of a commercial product. The degree of conversion (DC), Knoop microhardness, DOX release kinetics, antimicrobial, cytocompatibility, and anti-MMP activity of the modified adhesives were investigated. Incorporation of DOX-loaded nanotubes did not compromise DC, Knoop microhardness, or cell compatibility. Higher concentrations of DOX led to an increase in DOX release in a concentration-dependent manner from the modified adhesives. DOX released from the modified adhesives did not inhibit the growth of caries-related bacteria, but more importantly, it did inhibit MMP-1 activity. The loading of DOX into the nanotube-modified adhesives did not compromise the physicochemical properties of the adhesives and the released levels of DOX were able to inhibit MMP activity without cytotoxicity. Doxycycline released from the nanotube-modified adhesives inhibited MMP activity in a concentration-dependent fashion. Therefore, the proposed nanotube-modified adhesive may hold clinical potential as a strategy to preserve resin/dentin bond stability.

[The use of natural and synthetic hydrophilic polymers in the formulation of metformin hydrochloride tablets with different profile release].

Science.gov (United States)

Kołodziejczyk, Michał Krzysztof; Kołodziejska, Justyna; Zgoda, Marian Mikołaj

2012-01-01

Metformin hydrochloride after buformin and phenformin belongs to the group of biguanid derivatives used as oral anti-diabetic drugs. The object of the study is the technological analysis and the potential effect of biodegradable macromolecular polymers on the technological and therapeutic parameters of oral anti-diabetic medicinal products with metformin hydrochloride: Siofor, Formetic, Glucophage, Metformax in doses of 500mg and 1000mg and Glucophage XR in a dose of 500 mg of modified release. Market therapeutic products containing 500 and 1000 mg of metformin hydrochloride in a normal formulation and 500 mg of metformin hydrochloride in a formulation of modified release were analyzed. Following research methods were used: technological analysis of tablets, study of disintegration time of tablets, evaluation of pharmaceutical availability of metformin hydrochloride from tested therapeutic products, mathematical and kinetic analysis of release profiles of metformin hydrochloride, statistical analysis of mean differences of release coefficients. The percentage of excipients in the XR formulation is higher and constitutes 50.5% of a tablet mass. However, in standard formulations the percentage is lower, between 5.5% and 12.76%. On the basis of the results of disintegration time studies, the analysed therapeutic products can be divided into two groups, regardless the dose. The first one are preparations with faster (not fast!) disintegration: Glucophage i Metformax. The second group are preparations with slower disintegration, more balanced in the aspect of a high dose of the biologically active substance: Formetic and Siofor. Products with a lower content of excipients (Metformax, Glucophage) disintegrate in a faster way. The disintegration rate of the products with a higher content of excipients (Formetic, Siofor) is slower. The appearance of metformin hydrochloride concentration in the gastrointestinal contents, balanced in time, caused by a slower disintegration

Field study of the long-term release of block copolymers from fouling-release coatings

DEFF Research Database (Denmark)

Noguer, Albert Camós; Olsen, A.; Hvilsted, Søren

2017-01-01

The addition of block copolymers (i.e. oils) is a common technique to enhance the biofouling-resistance properties of poly(dimethylsiloxane) (PDMS)-based fouling-release coatings. These copolymers diffuse from the bulk to the surface of the coating, thus modifying the properties of the surface an...... fouling-release coatings. Finally, the potential of long-term field-studies is discussed, as compared to short-term laboratory experiments usually performed within fouling-release coatings studies....

Low Temperature Mechanical Properties of Scandium-Modified Al-Zn-Mg-Cu Alloys

National Research Council Canada - National Science Library

Senkov, O

2002-01-01

Tensile properties of three wrought alloys, (1) Al-10Zn-3Mg-1.2Cu-0.15Zr, (2) Al-10Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc, and (3) Al-12Zn-3Mg-1.2Cu-0.15Zr-0.39Mn-0.49Sc were studied in T6 and T7 conditions at 298K and 77K...

Synthesis of a novel thermo/pH sensitive nanogel based on salep modified graphene oxide for drug release

Energy Technology Data Exchange (ETDEWEB)

Bardajee, Ghasem Rezanejade, E-mail: rezanejad@pnu.ac.ir; Hooshyar, Zari; Farsi, Maryam; Mobini, Akram; Sang, Golnaz

2017-03-01

Nanogels (NGs) are three-dimensional water soluble cross-linked hydrogel materials in the nanoscale size range with a high loading capacity for guest molecules and act as drug carrier systems. In the present work, a new type of thermo/pH sensitive NG comprising salep modified graphene oxide (SMGO) with branched N-isopropylacrylamide (NIPAM) and acrylic acid (AA) was prepared. The SMGO/P(NIPAM-co-AA) NGs exhibited nanoporous structure and spherical particles with diameters about 82 nm as characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The samples were also characterized by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA) to further confirm about the formation of NGs. Doxorubicin (DOX) loaded SMGO/P(NIPAM-co-AA) NGs showed thermo/pH dependent releasing behavior: slow drug release at neutral pH and lower temperature but increased significantly in acidic pH and higher temperature, without any burst release. In addition, the NGs exhibited no effect on the cell viability in the tested concentration range up to 410 μg/mL and drug release systems enhanced toxicity to HeLa cells when compared to the equivalent dose of the free drug. Overall, our results put forth NGs as potential candidates in the development of a new nanocarrier for anti-cancer drug delivery. - Highlights: • A novel thermo/pH sensitive nanogels (NGs) was successfully synthesized. • NGs showed high loading capacity for DOX drug and slow drug release at neutral pH. • NGs exhibited no effect on the cell viability in the tested concentration range.

Synthesis of a novel thermo/pH sensitive nanogel based on salep modified graphene oxide for drug release

International Nuclear Information System (INIS)

Bardajee, Ghasem Rezanejade; Hooshyar, Zari; Farsi, Maryam; Mobini, Akram; Sang, Golnaz

2017-01-01

Nanogels (NGs) are three-dimensional water soluble cross-linked hydrogel materials in the nanoscale size range with a high loading capacity for guest molecules and act as drug carrier systems. In the present work, a new type of thermo/pH sensitive NG comprising salep modified graphene oxide (SMGO) with branched N-isopropylacrylamide (NIPAM) and acrylic acid (AA) was prepared. The SMGO/P(NIPAM-co-AA) NGs exhibited nanoporous structure and spherical particles with diameters about 82 nm as characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The samples were also characterized by Fourier transform infrared spectroscopy (FT-IR) and thermo gravimetric analysis (TGA) to further confirm about the formation of NGs. Doxorubicin (DOX) loaded SMGO/P(NIPAM-co-AA) NGs showed thermo/pH dependent releasing behavior: slow drug release at neutral pH and lower temperature but increased significantly in acidic pH and higher temperature, without any burst release. In addition, the NGs exhibited no effect on the cell viability in the tested concentration range up to 410 μg/mL and drug release systems enhanced toxicity to HeLa cells when compared to the equivalent dose of the free drug. Overall, our results put forth NGs as potential candidates in the development of a new nanocarrier for anti-cancer drug delivery. - Highlights: • A novel thermo/pH sensitive nanogels (NGs) was successfully synthesized. • NGs showed high loading capacity for DOX drug and slow drug release at neutral pH. • NGs exhibited no effect on the cell viability in the tested concentration range.

Challenges and opportunities in establishing scientific and regulatory standards for determining therapeutic equivalence of modified-release products: Workshop summary report.

Science.gov (United States)

Chen, Mei-Ling; Shah, Vinod P; Ganes, Derek; Midha, Kamal K; Caro, James; Nambiar, Prabu; Rocci, Mario L; Thombre, Avinash G; Abrahamsson, Bertil; Conner, Dale; Davit, Barbara; Fackler, Paul; Farrell, Colm; Gupta, Suneel; Katz, Russell; Mehta, Mehul; Preskorn, Sheldon H; Sanderink, Gerard; Stavchansky, Salomon; Temple, Robert; Wang, Yaning; Winkle, Helen; Yu, Lawrence

2010-09-01

Modified-release (MR) products are complex dosage forms designed to release drug in a controlled manner to achieve the desired efficacy and safety profiles. Inappropriate control of drug release from such products may result in reduced efficacy or increased toxicity. This paper is a summary report of the American Association of Pharmaceutical Scientists, International Pharmaceutical Federation, and Product Quality Research Institute workshop titled "Challenges and Opportunities in Establishing Scientific and Regulatory Standards for Assuring Therapeutic Equivalence of Modified Release Products", held October 1-2, 2009, in Baltimore, Maryland. The workshop provided an opportunity for pharmaceutical scientists from academia, industry, and regulatory agencies to discuss current regulatory expectations and industry practices for evaluating the pharmaceutical equivalence and bioequivalence of oral MR products. In the case of conventional monophasic MR formulations, the current regulatory approaches and criteria for bioequivalence evaluation were considered adequate for the assessment of therapeutic equivalence and inter-changeability of drug products. Additional measures may occasionally be needed to determine the bioequivalence of multiphasic MR products. The metric of partial AUC proposed by the US Food and Drug Administration received broad support as an additional measure for evaluating bioequivalence of multiphasic MR products designed to have a rapid onset of drug action followed by sustained response. The cutoff for partial AUCs may be based on the pharmacokinetic/pharmacodynamic or pharmacokinetic/ response characteristics of the products under examination. If the new metric is highly variable, the bioequivalence limits may be set based on the known within-subject variability for the reference product. The current regulatory approaches and criteria for bioequivalence evaluation were considered adequate for the assessment of therapeutic equivalence and

Production of biodiesel fuel by transesterification of different vegetable oils with methanol using Al₂O₃ modified MgZnO catalyst.

Science.gov (United States)

Olutoye, M A; Hameed, B H

2013-03-01

An active heterogeneous Al2O3 modified MgZnO (MgZnAlO) catalyst was prepared and the catalytic activity was investigated for the transesterification of different vegetable oils (refined palm oil, waste cooking palm oil, palm kernel oil and coconut oil) with methanol to produce biodiesel. The catalyst was characterized by using X-ray diffraction, Fourier transform infrared spectra, thermo gravimetric and differential thermal analysis to ascertain its versatility. Effects of important reaction parameters such as methanol to oil molar ratio, catalyst dosage, reaction temperature and reaction time on oil conversion were examined. Within the range of studied variability, the suitable transesterification conditions (methanol/oil ratio 16:1, catalyst loading 3.32 wt.%, reaction time 6h, temperature 182°C), the oil conversion of 98% could be achieved with reference to coconut oil in a single stage. The catalyst can be easily recovered and reused for five cycles without significant deactivation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Post-Mesozoic Rapid Increase of Seawater Mg/Ca due to Enhanced Mantle-Seawater Interaction

OpenAIRE

Marco Ligi; Enrico Bonatti; Marco Cuffaro; Daniele Brunelli

2013-01-01

The seawater Mg/Ca ratio increased significantly from ~ 80?Ma to present, as suggested by studies of carbonate veins in oceanic basalts and of fluid inclusions in halite. We show here that reactions of mantle-derived peridotites with seawater along slow spreading mid-ocean ridges contributed to the post-Cretaceous Mg/Ca increase. These reactions can release to modern seawater up to 20% of the yearly Mg river input. However, no significant peridotite-seawater interaction and Mg-release to the ...

Isoniazid release from suppositories compounded with selected bases.

Science.gov (United States)

Hudson, Kristofer C; Asbill, C Scott; Webster, Andrew A

2007-01-01

There is an increasing need for an alternative route of isoniazid adminstration for prophylaxis and treatment of tuberculosis in children. The purpose of this study is to evaluate the in vitro release of isoniazid from extemporaneously compounded isoniazid suppositories with a goal of optimizing the suppository dosage form for this indication. Suppositories were compounded using three different base formulations (cocoa butter, Witepsol H15 Base F, and a combination of polyethylene glycols 3350, 1000, and 400). The release profiles of six compounded suppositories with isoniazid (100 mg) were tested with a United States Pharmacopeial Convention-approved dissolution apparatus. Isoniazid concentrations at predetermined time points were determined using high-performance liquid chromatographic analysis. The results show that drug release from the water-solutble base (mixed polyethylene glycols) was significantly greater than that from the lipophilic bases (cocoa butter and Witepsol H15). The percentage of isoniazid release form the polyethylene glycol suppository formulation (70 +/- 1.4 mg/mL) was greater than that from the cocoa butter (55 +/- 1.1 mg/mL) and Witepsol H15 Base F (18 +/- 0.36 mg/mL) suppository formulations.

Loading and release of doxorubicin with magnetic nanotubes

Energy Technology Data Exchange (ETDEWEB)

Bai, Xia; Wang, Xiang; Lee, Sang Bok [Dept. of Chemistry and Biochemistry, University of Maryland, College Park (United States); English, Douglas [Dept. of Chemistry, Wichita State University, Wichita (United States)

2015-03-15

In this work, we study magnetic nanotubes (MNTs) as drug carriers to control the loading and release of doxorubicin (Dox). The inner surfaces of MNTs where Dox molecules are stored are modified with C18-silane and pyridine–silane. By tuning the interaction between the drug molecules and inner surfaces of MNTs via pH, Dox can be effectively encapsulated at pH 7.2 and released at pH 4.5. The successful loading of Dox is confirmed with confocal microscopy studies. The release profiles of Dox from modified MNTs are detected by spectrofluorophotometry, with bare MNTs as control. With proper modifications, MNTs can be used for pH-dependent, controlled release of drug molecules.

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics.

Science.gov (United States)

Ahmed, Osama A A; Hosny, Khaled M; Al-Sawahli, Majid M; Fahmy, Usama A

2015-01-01

The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV) nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid-liquid phase separation method, according to the Box-Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1), ethanol concentration (X2), and caseinate concentration (X3). The selected dependent variables were mean particle size (Y1), SMV encapsulation efficiency (Y2), and cumulative percentage of drug permeated after 1 hour (Y3). The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability from the optimized SMV-zein formulation, by fourfold relative to SMV suspension. Formulation of caseinate-coated SMV-zein nanoparticles improves the pharmacokinetic profile and bioavailability of SMV. Accordingly, improved hypolipidemic activities for longer duration could be achieved. In addition, the reduced dosage rate of SMV-zein nanoparticles improves patient tolerability and compliance.

Controlled release of ketorolac through nanocomposite films of hydrogel and LDH nanoparticles

International Nuclear Information System (INIS)

Xu Zhiping; Gu Zi; Cheng Xiaoxi; Rasoul, Firas; Whittaker, Andrew K.; Lu Gaoqing Max

2011-01-01

A novel nanocomposite film for sustained release of anionic ophthalmic drugs through a double-control process has been examined in this study. The film, made as a drug-loaded contact lens, consists principally of a polymer hydrogel of 2-hydroxyethyl methacrylate (HEMA), in whose matrix MgAl-layered double hydroxide (MgAl-LDH) nanoparticles intercalated with the anionic drug are well dispersed. Such nanocomposite films (hydrogel-LDH-drug) contained 0.6–0.8 mg of MgAl-LDH and 0.08–0.09 mg of the ophthalmic drug (ketorolac) in 1.0 g of hydrogel. MgAl-drug-LDH nanoparticles were prepared with the hydrodynamic particle size of 40–200 nm. TEM images show that these nanoparticles are evenly dispersed in the hydrogel matrix. In vitro release tests of hydrogel-LDH-drug in pH 7.4 PBS solution at 32 °C indicate a sustained release profile of the loaded drug for 1 week. The drug release undergoes a rapid initial burst and then a monotonically decreasing rate up to 168 h. The initial burst release is determined by the film thickness and the polymerization conditions, but the following release rate is very similar, with the effective diffusion coefficient being nearly constant (3.0 × 10 −12 m 2 /s). The drug release from the films is mechanistically attributed to anionic exchange and the subsequent diffusion in the hydrogel matrix.

Formulation and Study of Some Controlled Release Tablets with Pentoxifylline Based on Hydroxypropylcellulose Matrix Obtained by Wet Granulation Method with PEG 6000

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Gabriel Hancu

2011-01-01

Full Text Available In this work three formulations of modified release tablets
containing pentoxifylline 400 mg/tablet were obtained. Hydroxypropylcellulose (HPC in di®erent ratios was used as hydrophilic matrix agent. The pentoxifylline inclusion in the matrix has been carried out by water granulation, using PEG 6000 as binder. Tablets were obtained with a single station
tablet machine (Korsch, using standard pressure, and obtaining tablets with 13 mm diameter, 800 mg weight and 400 mg pentoxifylline per tablet. The weight uniformity, friability, hardness, thickness and disintegration of tablets were determined according to the stipulations of the 2001 Supplement of the Romanian Pharmacopoeia Xth edition. The experimental formulations with 400 mg pentoxifylline/tablet were studied by comparing them to the industrial reference product, Trental 400 mg (Aventis Pharma and in according
to the stipulations of Romanian Pharmacopoeia Xth edition, USP 27 and European Pharmacopoeia 5th edition. Every determination was performed using 20 tablets. We followed the comparison between dissolution profiles of slow release tablets containing pentoxifylline based on hydrophilic matrix. The dissolution studies were performed using the method from USP 24, using the paddle apparatus, and water as medium of dissolution at 37+/-0,5 Celsius degrees, at a rotation speed of 50 rpm. The determination was performed by spectrofotometric as say in UV at 274 nm. It was noticeable that regarding the weight uniformity, friability, hardness, thickness and disintegration the proposed formulations are comparable with the industrial reference product (Trental, 400 mg and are in agreement with the stipulations of the Romanian Pharmacopoeia Xth edition and European Pharmacopoeia 5th edition. The analysis of dissolution profiles showed that all formulations exhibit slow release.

Synthesis, crystal growth and structure of Mg containing β-rhombohedral boron: MgB17.4

International Nuclear Information System (INIS)

Adasch, Volker; Hess, Kai-Uwe; Ludwig, Thilo; Vojteer, Natascha; Hillebrecht, Harald

2006-01-01

For the first time, single crystals of Mg containing β-rhombohedral boron MgB 17.4 were synthesised from the elements in a Mg/Cu melt at 1600deg. C. The crystal structure determined by the refinement of single crystal data (space group R-3m, a=10.991(2)A, c=24.161(4)A, 890 reflections, 123 variables, R 1 (F)=0.049, wR 2 (I)=0.122) improves and modifies the former structure model derived from earlier investigations on powder samples. Mg is located on four different positions with partial occupation. While the occupation of the sites D (53.3%), E (91%) and F (7.2%) is already known from other boron-rich borides related to β-rhombohedral boron, the occupation of the fourth position (18h, 6.7%) is observed for the first time. Two boron positions show partial occupation. The summation reveals the composition MgB 17.4 and Mg 5.85 B 101.9 , respectively, confirmed by WDX measurements. The single crystals of MgB 17.4 show the highest Mg content ever found. Preliminary measurements indicate no superconductivity

Acid Inhibitory Effect of a Combination of Omeprazole and Sodium Bicarbonate (CDFR0209) Compared With Delayed-Release Omeprazole 40 mg Alone in Healthy Adult Male Subjects.

Science.gov (United States)

Kim, Kyu-Nam; Yang, Sung-Won; Kim, Hyunil; Kwak, Seong Shin; Kim, Young-Sang; Cho, Doo-Yeoun

2018-01-01

CDFR0209, a combination of an immediate-release formulation of omeprazole 40 mg and sodium bicarbonate 1100 mg, has been developed to treat acid-related disorders. We compared the acid inhibitory effects of CDFR0209 and delayed-release omeprazole (omeprazole-DR, Losec 40 mg) after repeated dosing in Helicobacter pylori-negative healthy adult male subjects. In this 2-period crossover study, 30 subjects were randomized to CDFR0209 or omeprazole-DR daily for 7 days. An ambulatory continuous 24-hour intragastric pH recording was performed at baseline and on days 1 and 7 of each administration period. Integrated gastric acidity was calculated from time-weighted average hydrogen ion concentrations at each hour of the 24-hour record. An analysis of variance model was used to test the pharmacodynamic equivalence of CDFR0209 and omeprazole-DR, using the natural logarithmic transformation of the percent decrease from baseline in integrated gastric acidity for the 24-hour interval after the seventh dose of each omeprazole formulation. The geometric least-squares mean ratios (CDFR0209/omeprazole-DR) of the percent decrease from baseline in integrated gastric acidity was 0.98 (90%CI, 0.93-1.07). Both CDFR0209 and omeprazole-DR are equally effective in decreasing integrated gastric acidity at steady state. © 2017, The American College of Clinical Pharmacology.

DaonilÒ y glibenclamida 5 mg de producción nacional: liberación in vitro Daonil ® and glibenclamide 5 mg of national production: release in vitro

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Diana Pereda Rodríguez

2007-04-01

Full Text Available Dentro del proceso global de la liberación de un fármaco, la disolución es el paso más importante pues está íntimamente relacionado con los procesos de absorción, determinantes en la biodisponibilidad de un medicamento administrado por vía oral. En el presente trabajo se realizaron los perfiles de disolución de 2 lotes de DaonilÒ (Hoechst Farma SA, Barcelona, medicamento líder del principio activo glibenclamida (DCI, y de 3 lotes de glibenclamida 5 mg de producción nacional. Los datos de porcentaje de principio activo liberado contra tiempo se sometieron a un estudio de ajuste a 4 modelos comunes a perfiles de disolución mediante el programa CurveExpert y se realizó la comparación estadística de los perfiles de disolución con la utilización de un método independiente de modelo matemático (f2: factor de similitud. Los lotes estudiados no cumplen con los criterios de la Food and Drug Administration (FDA para los estudios de equivalencia in vitro y muestran diferencias significativas (p 0,05 sus perfiles de disolución.Dissolution is the most important step in the global release process of a drug, since it is closely related to the absorption processes, which are determinant in the bioavailability of a drug administered by oral route. The dissolution profiles of two batches of Daonil® (Hoechst Farma SA Barcelona, a leading drug of the glibenclamide active principle (DCI, and of 3 batches of glibenclamide 5 mg of national production were studied. The percentage data of the active principle released against time were subjected to a study of adjustment of 4 models to common dissolution profiles by the CurveExpert program, and the statistical comparison of dissolution profiles was made by using a mathematical independent model (f2: similarity factor. All the batches studied do not fulfill the criteria of the Food and Drug Administration (FDA for the in vitro equivalence studies and showed significant differences in their

Modifying an Active Compound’s Release Kinetic Using a Supercritical Impregnation Process to Incorporate an Active Agent into PLA Electrospun Mats

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Carol López de Dicastillo

2018-04-01

Full Text Available The main objective of this work was to study the release of cinnamaldehyde (CIN from electrospun poly lactic acid (e-PLA mats obtained through two techniques: (i direct incorporation of active compound during the electrospinning process (e-PLA-CIN; and (ii supercritical carbon dioxide (scCO2 impregnation of CIN within electrospun PLA mats (e-PLA/CINimp. The development and characterization of both of these active electrospun mats were investigated with the main purpose of modifying the release kinetic of this active compound. Morphological, structural, and thermal properties of these materials were also studied, and control mats e-PLA and e- PLA CO 2 were developed in order to understand the effect of electrospinning and scCO2 impregnation, respectively, on PLA properties. Both strategies of incorporation of this active compound into PLA matrix resulted in different morphologies that influenced chemical and physical properties of these composites and in different release kinetics of CIN. The electrospinning and scCO2 impregnation processes and the presence of CIN altered PLA thermal and structural properties when compared to an extruded PLA material. The incorporation of CIN through scCO2 impregnation resulted in higher release rate and lower diffusion coefficients when compared to active electrospun mats with CIN incorporated during the electrospinning process.

Perbandingan Pemberian Ondansetron 8 mg dengan Tramadol 1 mg/ kgBB Intravena untuk Mencegah Menggigil Pascaanestesi Umum pada Operasi Mastektomi Radikal atau Modifikasi

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Mirza Oktavian

2014-04-01

Full Text Available ost anesthetic shivering is a common complication of general anesthesia and preventable with several types of drugs. The aim of this study was to compare the efficacy of intravenous 8mg ondansetron versus tramadol 1 mg/kgBW in preventing post anesthetic shivering after general anesthesia. The research is a prospective, randomized double-blind controlled study involving 38 female patients aged 30–65 years at Dr. Hasan Sadikin Hospital Bandung period March–April 2012, American Society of Anesthesiologist (ASA physical status I–II, who underwent radical or modified mastectomy. Subjects were randomly divided into two groups. One group was given ondansetron 8 mg and the other group was given tramadol 1 mg/kgBW before surgical wound closure. Research results showed that incidence of post anesthetic shivering was less on tramadol group (15.8% compared to ondansetron (52.6% group, which is statistically significant (p<0.05. In conclusion, administration of tramadol 1 mg/kgBW intravenously is more effective in preventing post anesthetic shivering in radical or modified mastectomy.

Magnetic silica hybrids modified with guanidine containing co-polymers for drug delivery applications

Energy Technology Data Exchange (ETDEWEB)

Timin, Alexander S., E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); RASA Center in Tomsk, Tomsk Polytechnic University, 30, Lenin Avenue, 634500 Tomsk (Russian Federation); Khashirova, Svetlana Yu. [Kabardino-Balkar State University, ul. Chernyshevskogo 173, Nal' chik, 360004 Kabardino-Balkaria (Russian Federation); Rumyantsev, Evgeniy V.; Goncharenko, Alexander A. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation)

2016-07-01

Guanidine containing co-polymers grafted onto silica nanoparticles to form core-shell structure were prepared by sol-gel method in the presence of γ-Fe{sub 2}O{sub 3} nanoparticles. The morphological features for uncoated and coated silica particles have been characterized with scanning electron microscopy. The results show that the polymer coated silicas exhibit spherical morphology with rough polymeric surface covered by γ-Fe{sub 2}O{sub 3} nanoparticles. The grafting amount of guanidine containing co-polymers evaluated by thermogravimetric analysis was in the range from 17 to 30%. Then, the drug loading properties and cumulative release of silica hybrids modified with guanidine containing co-polymers were evaluated using molsidomine as a model drug. It was shown that after polymer grafting the loading content of molsidomine could reach up to 3.42 ± 0.21 and 2.34 ± 0.14 mg/g respectively. The maximum drug release of molsidomine is achieved at pH 1.6 (approximately 71–75% release at 37 °C), whereas at pH 7.4 drug release is lower (50.4–59.6% release at 37 °C). These results have an important implication that our magneto-controlled silica hybrids modified with guanidine containing co-polymers are promising as drug carriers with controlled behaviour under influence of magnetic field. - Highlights: • Polymer coated silica hybrids containing γ-Fe{sub 2}O{sub 3} were prepared via sol–gel method. • Polymer grafting influences pH-response and surface properties of final products. • Molsidomine as a model drug was effectively loaded into polymer coated silicas. • The drug loading depends on the nature of grafted polymer and its content.

In situ microemulsion synthesis of hydroxyapatite-MgFe{sub 2}O{sub 4} nanocomposite as a magnetic drug delivery system

Energy Technology Data Exchange (ETDEWEB)

Foroughi, Firoozeh [Young Researchers and Elite Club, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Hassanzadeh-Tabrizi, S.A., E-mail: tabrizi1980@gmail.com [Young Researchers and Elite Club, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Bigham, Ashkan [Advanced Materials Research Center, Department of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of)

2016-11-01

In this study, an innovative synthesis process has been developed to produce hydroxyapatite-magnesium ferrite (HA-MgFe{sub 2}O{sub 4}) nanocomposite. In addition, the effect of calcination temperature on drug delivery behavior of produced samples was investigated. HA-MgFe{sub 2}O{sub 4} nanocomposite was prepared via one-step modified reverse microemulsion synthesis route. The resulting products were characterized by X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and Brunauer–Emmett–Teller surface area analysis (BET). The calcined samples at 500 and 700 °C demonstrated mesoporous characteristics and large specific surface areas of 88 and 32 m{sup 2}/g, respectively. TEM and VSM results showed that the nanocomposite calcined at 700 °C has core–shell morphology and a maximum saturation magnetization of 9.47 emu g{sup −1}. - Highlights: • A one-step modified reverse microemulsion method has been used to produce hydroxyapatite-magnesium ferrite. • Nanocomposites were loaded with ibuprofen as a magnetic drug delivery system. • The drug release behavior of nanocomposites were studied at different calcination temperature.

Different serotonin receptor types participate in 5-hydroxytryptophan-induced gonadotropins and prolactin release in the female infantile rat.

Science.gov (United States)

Lacau-Mengido, I M; Libertun, C; Becú-Villalobos, D

1996-05-01

Serotonin (5-HT) receptors can be classified into at least three, possibly up to seven, classes of receptors. They comprise the 5-HT1, 5-HT2, and 5-HT3 classes, the "uncloned' 5-HT4 receptor and the recombinant receptors 5-ht5, 5-ht6 and 5-ht7. We investigated the role of different serotonin receptor types in a neuroendocrine response to the activation of the serotonergic system. Female immature rats were chosen as an experimental model as it has been shown that during the 3rd week of life, and not at later developmental stages, 5-hydroxytryptophan (5-HTP, a serotonin precursor) induces gonadotropin release in females and not in males. Besides, at this age, serotonin releases prolactin in both sexes. 5-HTP (50 mg/kg) released prolactin, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as expected. Ketanserin (5-HT2A antagonist) and methysergide (5-HT2C antagonist) blocked 5-HTP-induced prolactin release, but did not block the LH or FSH responses. Ondansetron (5-HT3 receptor antagonist) did not modify prolactin response to 5-HTP, whereas it blocked 5-HTP-induced LH and FSH release. Propranolol (5-HT1 and beta-adrenergic antagonist) blocked prolactin, LH and FSH release induced by 5-HTP. The 5-HT2C agonist 1-(3-chlorophenyl)piperazine dihydrochloride released prolactin, without modifying LH or FSH release. Methyl-quipazine and phenylbiguanide (5-HT3 agonists) increased both LH and FSH levels, without altering prolactin secretion. The present experiments indicate that serotonin acting at the 5-HT3 receptor mediates LH and FSH release in infantile female rats, whereas 5-HT2C or 2A receptor types participate in the release of prolactin at this age. 5-HT1 receptor type may be involved in the release of the three hormones, though a beta-adrenergic component of the response cannot be discarded.

Preparation of the fast setting and degrading Ca–Si–Mg cement with both odontogenesis and angiogenesis differentiation of human periodontal ligament cells

Energy Technology Data Exchange (ETDEWEB)

Chen, Yi-Wen [Graduate Institute of Clinical Medical Science, China Medical University, Taichung City, Taiwan (China); 3D Printing Medical Research Center, China Medical University Hospital, Taichung City, Taiwan (China); Hsu, Tuan-Ti [Institute of Oral Science, Chung Shan Medical University, Taichung City, Taiwan (China); Wang, Kan [H. Milton Stewart School of Industrial and Systems Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Georgia Tech Manufacturing Institute, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Shie, Ming-You, E-mail: eviltacasi@gmail.com [3D Printing Medical Research Center, China Medical University Hospital, Taichung City, Taiwan (China)

2016-03-01

Develop a fast setting and controllable degrading magnesium–calcium silicate cement (Mg–CS) by sol–gel, and establish a mechanism using Mg ions to stimulate human periodontal ligament cells (hPDLs) are two purposes of this study. We have used the diametral tensile strength measurement to obtain the mechanical strength and stability of Mg–CS cement; in addition, the cement degradation properties is realized by measuring the releasing amount of Si and Mg ions in the simulated body fluid. The other cell characteristics of hPDLs, such as proliferation, differentiation and mineralization were examined while hPDLs were cultured on specimen surfaces. This study found out the degradation rate of Mg–CS cements depends on the Mg content in CS. Regarding in vitro bioactivity; the CS cements were covered with abundant clusters of apatite spherulites after immersion of 24 h, while less apatite spherulites were formatted on the Mg-rich cement surfaces. In addition, the authors also explored the effects of Mg ions on the odontogenesis and angiogenesis differentiation of hPDLs in comparison with CS cement. The proliferation, alkaline phosphatase, odontogenesis-related genes (DSPP and DMP-1), and angiogenesis-related protein (vWF and ang-1) secretion of hPDLs were significantly stimulated when the Mg content of the specimen was increased. The results in this study suggest that Mg–CS materials with this modified composition could stimulate hPDLs behavior and can be good bioceramics for bone substitutes and hard tissue regeneration applications as they stimulate odontogenesis/angiogenesis. - Highlights: • The fast setting and degrading Mg–CS cement was synthesized by sol–gel. • Promoted proliferation of hPDLs on Mg–CS specimens • Mg–CS can degrade and release Si and Mg ions into SBF. • Up-regulation of odontogenic and angiogenic of hPDLs • Mg–CS may be good bone substitutes for hard tissue regeneration applications.

Preparation of the fast setting and degrading Ca–Si–Mg cement with both odontogenesis and angiogenesis differentiation of human periodontal ligament cells

International Nuclear Information System (INIS)

Chen, Yi-Wen; Hsu, Tuan-Ti; Wang, Kan; Shie, Ming-You

2016-01-01

Develop a fast setting and controllable degrading magnesium–calcium silicate cement (Mg–CS) by sol–gel, and establish a mechanism using Mg ions to stimulate human periodontal ligament cells (hPDLs) are two purposes of this study. We have used the diametral tensile strength measurement to obtain the mechanical strength and stability of Mg–CS cement; in addition, the cement degradation properties is realized by measuring the releasing amount of Si and Mg ions in the simulated body fluid. The other cell characteristics of hPDLs, such as proliferation, differentiation and mineralization were examined while hPDLs were cultured on specimen surfaces. This study found out the degradation rate of Mg–CS cements depends on the Mg content in CS. Regarding in vitro bioactivity; the CS cements were covered with abundant clusters of apatite spherulites after immersion of 24 h, while less apatite spherulites were formatted on the Mg-rich cement surfaces. In addition, the authors also explored the effects of Mg ions on the odontogenesis and angiogenesis differentiation of hPDLs in comparison with CS cement. The proliferation, alkaline phosphatase, odontogenesis-related genes (DSPP and DMP-1), and angiogenesis-related protein (vWF and ang-1) secretion of hPDLs were significantly stimulated when the Mg content of the specimen was increased. The results in this study suggest that Mg–CS materials with this modified composition could stimulate hPDLs behavior and can be good bioceramics for bone substitutes and hard tissue regeneration applications as they stimulate odontogenesis/angiogenesis. - Highlights: • The fast setting and degrading Mg–CS cement was synthesized by sol–gel. • Promoted proliferation of hPDLs on Mg–CS specimens • Mg–CS can degrade and release Si and Mg ions into SBF. • Up-regulation of odontogenic and angiogenic of hPDLs • Mg–CS may be good bone substitutes for hard tissue regeneration applications.

Development and evaluation of sustained release losartan potassium matrix tablet using kollidon SR as release retardant

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Shahid Sarwar

2012-12-01

Full Text Available The present study was undertaken to develop sustained release (SR matrix tablets of losartan potassium, an angiotensin-II antagonist for the treatment of hypertension. The tablets were prepared by direct compression method, along with Kollidon SR as release retardant polymer. The amount of losartan potassium remains fixed (100 mg for all the three formulations whereas the amounts of Kollidon SR were 250 mg, 225 mg, and 200 mg for F-1, F-2, and F-3 respectively. The evaluation involves three stages: the micromeritic properties evaluation of granules, physical property studies of tablets, and in-vitro release kinetics studies. The USP apparatus type II was selected to perform the dissolution test, and the dissolution medium was 900 mL phosphate buffer pH 6.8. The test was carried out at 75 rpm, and the temperature was maintained at 37 ºC ± 0.5 ºC. The release kinetics was analyzed using several kinetics models. Higher polymeric content in the matrix decreased the release rate of drug. At lower polymeric level, the rate and extent of drug release were enhanced. All the formulations followed Higuchi release kinetics where the Regression co-efficient (R² values are 0.958, 0.944, and 0.920 for F-1, F-2, and F-3 respectively, and they exhibited diffusion dominated drug release. Statistically significant (PO presente estudo foi realizado para desenvolver (SR matriz de comprimidos de liberação sustentada de losartana, um antagonista da angiotensina II, para o tratamento da hipertensão arterial. Os comprimidos foram preparados pelo método de compressão direta com Kollidon SR como polímero de liberação lenta. A quantidade de losartana potássica permanece fixa (100 mg para todas as três formulações enquanto que as quantidades de Kollidon SR foram de 250 mg, 225 mg e 200 mg para F-1, F-2 e F-3, respectivamente. A avaliação envolve três etapas- propriedades micromeríticas dos grânulos, estudo das propriedades físicas dos comprimidos e

Renal-targeted delivery of triptolide by entrapment in pegylated TRX-20-modified liposomes.

Science.gov (United States)

Yuan, Zhi-Xiang; Jia, Lu; Lim, Lee Yong; Lin, Ju-Chun; Shu, Gang; Zhao, Ling; Ye, Gang; Liang, Xiao-Xia; Ji, Hongming; Fu, Hua-Lin

2017-01-01

Previously, 3,5-dipentadecyloxybenzamidine hydrochloride (TRX-20)-modified liposomes were reported to specifically target mesangial cells (MCs) in glomeruli. To further gain a better understanding of the characteristics and potential application for glomerular diseases of TRX-20-modified liposomes, we synthesized TRX-20 and prepared TRX-20-modified liposomes (TRX-LPs) with different molar ratios - 6% (6%-TRX-LP), 11% (11%-TRX-LP), and 14% (14%-TRX-LP) - of TRX-20 to total lipid in the present study. All TRX-LPs exhibited concentration-dependent toxicity against the MCs at a lipid concentration ranging from 0.01 to 1.0 mg/mL with IC 50 values of 3.45, 1.13, and 0.55 mg/mL, respectively. Comparison of the cell viability of TRX-LPs indicated that high levels of TRX-20 caused severe cell mortality, with 11%-TRX-LP showing the higher cytoplasmic accumulation in the MCs. Triptolide (TP) as a model drug was first loaded into 11%-TRX-LP and the liposomes were further modified with PEG 5000 (PEG-TRX-TP-LP) in an attempt to prolong their circulation in blood and enhance TP-mediated immune suppression. Due to specific binding to MCs, PEG-TRX-TP-LP undoubtedly showed better anti-inflammatory action in vitro, evidenced by the inhibition of release of nitric oxide (NO) and tumor necrosis factor-α from lipopolysaccharide-stimulated MCs, compared with free TP at the same dose. In vivo, the PEG-TRX-TP-LP effectively attenuated the symptoms of membranous nephropathic (MN) rats and improved biochemical markers including proteinuria, serum cholesterol, and albumin. Therefore, it can be concluded that the TRX-modified liposome is an effective platform to target the delivery of TP to glomeruli for the treatment of MN.

Fluoride releasing and enamel demineralization around orthodontic brackets by fluoride-releasing composite containing nanoparticles.

Science.gov (United States)

Melo, Mary A S; Morais, Weslanny A; Passos, Vanara F; Lima, Juliana P M; Rodrigues, Lidiany K A

2014-05-01

Fluoride-containing materials have been suggested to control enamel demineralization around orthodontic brackets during the treatment with fixed appliances. The improvement of their properties has been made through innovations, such as the application of nanotechnology by incorporation of nanofillers. This in vitro study evaluated the capacity of fluoride releasing and enamel demineralization inhibition of fluoride-releasing nanofilled cement around orthodontic brackets using an artificial caries biofilm model. Forty bovine enamel discs were selected by evaluating surface microhardness and randomized into four groups (n = 10): non-fluoride-releasing microfilled composite, fluoride-releasing microfilled composite, resin-modified glass ionomer cement (RMGI), and fluoride-releasing nanofilled composite (FN). After brackets bonding in each disc, the specimens were subjected to a cariogenic challenge through a Streptococcus mutans biofilm model. After the experimental period, the biofilm formed around the brackets was collected for fluoride analysis and the mineral loss around the brackets was determined by integrated demineralization via cross-sectional microhardness measurement at 20 and 70 μm from the bracket margin. Additionally, samples of each group were subjected to energy-dispersive X-ray spectroscopy (EDX) analysis examined under a scanning electron microscopy (SEM). ANOVA followed by Tukey test were applied for fluoride concentration and mineral loss data, respectively. At both distances, only RMGI statistically differed from the other groups presenting the lowest demineralization, although there was a trend to a lower demineralization of enamel around brackets in FN group. Similar condition was found to fluoride concentration and EDX/SEM analysis. Under the cariogenic exposure condition of this study, the fluoride-releasing nanofilled material had similar performance to fluoride-releasing microfilled materials. The presence of nanofillers in the fluoride-releasing

Tofacitinib 5 mg Twice Daily in Patients with Rheumatoid Arthritis and Inadequate Response to Disease-Modifying Antirheumatic Drugs: A Comprehensive Review of Phase 3 Efficacy and Safety.

Science.gov (United States)

Bird, Paul; Bensen, William; El-Zorkany, Bassel; Kaine, Jeffrey; Manapat-Reyes, Bernadette Heizel; Pascual-Ramos, Virginia; Witcombe, David; Soma, Koshika; Zhang, Richard; Thirunavukkarasu, Krishan

2018-05-24

Tofacitinib is an oral Janus kinase inhibitor for the treatment of rheumatoid arthritis (RA). We performed a comprehensive review of phase 3 studies of tofacitinib 5 mg twice daily (BID) (approved dose in many countries) in patients with moderate to severe RA and inadequate response to prior disease-modifying antirheumatic drugs. A search of PubMed and ClinicalTrials.gov identified 5 studies: ORAL Solo (NCT00814307), ORAL Sync (NCT00856544), ORAL Standard (included adalimumab 40 mg once every 2 weeks; NCT00853385), ORAL Scan (NCT00847613), and ORAL Step (NCT00960440). Efficacy and safety data for tofacitinib 5 mg BID, placebo, and adalimumab were analyzed. Across the 5 studies, 1216 patients received tofacitinib 5 mg BID, 681 received placebo, and 204 received adalimumab. At month 3, tofacitinib demonstrated significantly higher 20%, 50%, and 70% improvement in American College of Rheumatology response criteria (ACR20, ACR50, and ACR70, respectively) response rates, greater improvement in Health Assessment Questionnaire-Disability Index, and a higher proportion of Disease Activity Score-defined remission than placebo. Frequencies of adverse events (AEs), serious AEs, and discontinuations due to AEs were similar for tofacitinib and placebo at month 3; serious infection events were more frequent for tofacitinib. In ORAL Standard, although not powered for formal comparisons, tofacitinib and adalimumab had numerically similar efficacy and AEs; serious AEs and serious infection events were more frequent with tofacitinib. Tofacitinib 5 mg BID reduced RA signs and symptoms and improved physical function versus placebo in patients with inadequate response to prior disease-modifying antirheumatic drugs. Tofacitinib 5 mg BID had a consistent, manageable safety profile across studies, with no new safety signals identified.This is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where

Controlled release system for ametryn using polymer microspheres: Preparation, characterization and release kinetics in water

International Nuclear Information System (INIS)

Grillo, Renato; Pereira, Anderson do Espirito Santo; Ferreira Silva de Melo, Nathalie; Porto, Raquel Martins; Feitosa, Leandro Oliveira; Tonello, Paulo Sergio; Dias Filho, Newton L.; Rosa, Andre Henrique; Lima, Renata; Fraceto, Leonardo Fernandes

2011-01-01

The purpose of this work was to develop a modified release system for the herbicide ametryn by encapsulating the active substance in biodegradable polymer microparticles produced using the polymers poly(hydroxybutyrate) (PHB) or poly(hydroxybutyrate-valerate) (PHBV), in order to both improve the herbicidal action and reduce environmental toxicity. PHB or PHBV microparticles containing ametryn were prepared and the efficiencies of herbicide association and loading were evaluated, presenting similar values of approximately 40%. The microparticles were characterized by scanning electron microscopy (SEM), which showed that the average sizes of the PHB and PHBV microparticles were 5.92 ± 0.74 μm and 5.63 ± 0.68 μm, respectively. The ametryn release profile was modified when it was encapsulated in the microparticles, with slower and more sustained release compared to the release profile of pure ametryn. When ametryn was associated with the PHB and PHBV microparticles, the amount of herbicide released in the same period of time was significantly reduced, declining to 75% and 87%, respectively. For both types of microparticle (PHB and PHBV) the release of ametryn was by diffusion processes due to anomalous transport (governed by diffusion and relaxation of the polymer chains), which did not follow Fick's laws of diffusion. The results presented in this paper are promising, in view of the successful encapsulation of ametryn in PHB or PHBV polymer microparticles, and indications that this system may help reduce the impacts caused by the herbicide, making it an environmentally safer alternative.

Bioactive Glass Nanoparticles as a New Delivery System for Sustained 5-Fluorouracil Release: Characterization and Evaluation of Drug Release Mechanism

Directory of Open Access Journals (Sweden)

Abeer M. El-Kady

2015-01-01

Full Text Available Bioactive glass nanoparticles were synthesized and tested for the first time as a new delivery system for sustained 5-fluorouracil (5-FU release. They were characterized by TEM, DTA, TGA, and FT-IR. The porosity % and specific surface area of glass nanoparticles were 85.59% and 378.36 m2/g, respectively. The in vitro bioactivity evaluation confirmed that bioactive glass disks prepared from these nanoparticles could induce hydroxyapatite layer over their surfaces in simulated body fluid. The in vitro drug release experiment indicated that glass nanoparticles could serve as long-term local delivery vehicles for sustained 5-FU release. The release profile of 5-FU showed an initial fast release stage followed by a second stage of slower release. The initial burst release of 5-FU in the first day was about 23% (28.92 mg·L−1 of the total amount of loaded 5-FU, while the final cumulative percentage of the 5-FU released after 32 days was about 45.6% (57.31 mg·L−1 of the total amount of loaded 5-FU. The application of different mathematical models indicated that 5-FU was released by diffusion controlled mechanism and suggested that its release rate was dependent on glass particles dissolution, changes of surface area as well as diameter of glass particles, and concentration of loaded drug.

An understanding of modified release matrix tablets behavior during drug dissolution as the key for prediction of pharmaceutical product performance - case study of multimodal characterization of quetiapine fumarate tablets.

Science.gov (United States)

Kulinowski, Piotr; Woyna-Orlewicz, Krzysztof; Rappen, Gerd-Martin; Haznar-Garbacz, Dorota; Węglarz, Władysław P; Dorożyński, Przemysław P

2015-04-30

Motivation for the study was the lack of dedicated and effective research and development (R&D) in vitro methods for oral, generic, modified release formulations. The purpose of the research was to assess multimodal in vitro methodology for further bioequivalence study risk minimization. Principal results of the study are as follows: (i) Pharmaceutically equivalent quetiapine fumarate extended release dosage form of Seroquel XR was developed using a quality by design/design of experiment (QbD/DoE) paradigm. (ii) The developed formulation was then compared with originator using X-ray microtomography, magnetic resonance imaging and texture analysis. Despite similarity in terms of compendial dissolution test, developed and original dosage forms differed in micro/meso structure and consequently in mechanical properties. (iii) These differences were found to be the key factors of failure of biorelevant dissolution test using the stress dissolution apparatus. Major conclusions are as follows: (i) Imaging methods allow to assess internal features of the hydrating extended release matrix and together with the stress dissolution test allow to rationalize the design of generic formulations at the in vitro level. (ii) Technological impact on formulation properties e.g., on pore formation in hydrating matrices cannot be overlooked when designing modified release dosage forms. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of solution concentration on sealing treatment of Mg-Al hydrotalcite film on AZ91D Mg alloy

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Qiangsheng Dong

2017-09-01

Full Text Available Cerium-based sealing treatment was developed for Mg-Al hydrotalcite film on AZ91D Mg alloy, and the influence of cerium salt solution was investigated to modify the surface integrity and corrosion resistance. Scanning electron microscope (SEM and X-ray diffraction (XRD measurements were carried out to analyze the surface morphology and phase composition. The corrosion resistance of Mg-Al hydrotalcite film after sealing treatment was evaluated by the polarization curve and electrochemical impedance spectroscopy (EIS tests. The results showed that lower concentration of Ce-containing solution was beneficial to seal the micro-cracks on Mg-Al hydrotalcite film, and improve the surface integrity and corrosion resistance; higher concentration of Ce-containing solution could seal fewer micro-cracks, and the corrosion resistance was decreased owing to the disintegration of Mg-Al hydrotalcite film.

Comments on ”Evidence of the hydrogen release mechanism in bulk MgH2”

Science.gov (United States)

Surrey, Alexander; Nielsch, Kornelius; Rellinghaus, Bernd

2017-04-01

The effect of an electron beam induced dehydrogenation of MgH2 in the transmission electron microscope (TEM) is largely underestimated by Nogita et al., and led the authors to a misinterpretation of their TEM observations. Firstly, the selected area diffraction (SAD) pattern is falsely interpreted. A re-evaluation of the SAD pattern reveals that no MgH2 is present in the sample, but that it rather consists of Mg and MgO only. Secondly, the transformation of the sample upon in-situ heating in the TEM cannot be ascribed to dehydrogenation, but is rather to be explained by the (nanoscale) Kirkendall effect, which leads to the formation of hollow MgO shells without any metallic Mg in their cores. Hence, the conclusions drawn from the TEM investigation are invalid, as the authors apparently have never studied MgH2.

Phase controlled synthesis of (Mg, Ca, Ba)-ferrite magnetic nanoparticles with high uniformity

International Nuclear Information System (INIS)

Wang, S.F.; Li, Q.; Zu, X.T.; Xiang, X.; Liu, W.; Li, S.

2016-01-01

(Mg, Ca, Ba)-ferrite magnetic nanoparticles were successfully synthesized through modifying the atomic ratio of polysaccharide and chelating agent at an optimal sintering temperature. In the process, the polysaccharide plays an important role in drastically shrinking the precursor during the gel drying process. In the metal-complex structure, M"2"+ ion active sites were coordinated by −OH of the water molecules except for EDTA anions. The MFe_2O_4 magnetic nanoparticles exhibited enhanced magnetic properties when compared with nano-MFe_2O_4 of similar particle size synthesized by other synthesis route reported in the literature. In particular, the sintering temperature improves the crystallinity and increases the hysteresis loop squareness ratio of (Mg, Ca, Ba)-ferrite nanoparticles significantly. - Graphical abstract: Schematic representation of the proposed model for MFe_2O_4 nanoparticle synthesis, starting from EDTA-chelated M"2"+ (M=Mg, Ca, or Ba) cations (left). High dispersion (Mg, Ca, Ba)-ferrite magnetic nanoparticles were prepared by a modified polyacrylamide gel route. Optimized utilization of polysaccharide, chelating agent, and sintering temperature allowed the formation of (Mg, Ca, Ba)-ferrite nanoparticles with a narrow diameter distribution. - Highlights: • We report a modified polyacrylamide gel route to synthesize (Mg, Ca, Ba)-ferrite magnetic nanoparticles. • Chelate mechanism of metal ions (Mg, Ca, Ba) and EDTA has been discussed. • Phase transformation process of (Mg, Ca, Ba)-ferrites has been discussed. • The preparation method increases the hysteresis loop squareness ratio of (Mg, Ca, Ba)-ferrite nanoparticles.

Sustained Release of a Water-Soluble Drug from Directly ...

African Journals Online (AJOL)

Okra gum was evaluated as a controlled-release agent in modified release matrices in comparison with sodium carboxymethylcellulose (NaCMC) using aspirin as the model drug. Tablets were produced by direct compression and the in vitro drug release was assessed under conditions similar to those in the gastrointestinal ...

Synthesis of Zn(BH{sub 4}){sub 2} and Gas Absorption and Release Characteristics of Zn(BH{sub 4}){sub 2}, Ni, or Ti-Added MgH{sub 2}–Based Alloys

Energy Technology Data Exchange (ETDEWEB)

Kwak, Young Jun; Lee, Seong Ho; Kwon, Sung Nam; Park Il Woo; Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of)

2015-07-15

A sample [named Zn(BH{sub 4}){sub 2}(+NaCl)] was synthesized by milling ZnCl{sub 2} and NaBH{sub 4} at 400 rpm under argon gas for 2 h. And Zn(BH{sub 4}){sub 2}(+NaCl)+MgH{sub 2} sample was prepared by milling MgH{sub 2} in a planetary ball mill and mixing with the Zn(BH{sub 4}){sub 2}(+NaCl) synthesized by milling for 4 h in a mortar with a pestle. Then the gas-release characteristics of the two samples were investrigated. Analyses of XRD patterns and FT-IR spectra, as well as TGA, DTA, and SEM observations, were also performed. After heating the samples to 400 ℃, the weight losses of Zn(BH{sub 4}){sub 2}(+NaCl) and Zn(BH{sub 4}){sub 2}(+NaCl)+MgH{sub 2} were 11.2 and 8.2 wt%, respectively, with respect to the sample weight. The DTA results for the two samples showed a decomposition peak for Zn(BH{sub 4}){sub 2} at about 61 ℃. The DTA result of Zn(BH{sub 4}){sub 2}(+NaCl) + MgH{sub 2} showed a decomposition peak for MgH{sub 2} at about 374 ℃. A sample of Zn(BH{sub 4}){sub 2}(+NaCl)+MgH{sub 2} to which Ni, and Ti were added, with a composition of 90 wt% MgH{sub 2}-5 wt% Zn(BH{sub 4}){sub 2}(+NaCl)-2.5 wt% Ni-2.5 wt% Ti, in which a large amount of MgH2 is contained in order to make a large quantity of hydrogen be absorbed and released reversibly, was also prepared. The experimental results showed that addition of Zn(BH{sub 4}){sub 2}(+NaCl), Ni, or Ti increased the dehydriding rate of MgH{sub 2}, while decreased its initial hydriding rate.

[Studies on preparation and dissolution test in vitro of sustained-release dropping pills of curcumin].

Science.gov (United States)

Fang, Yu; Xiang, Bai; Pan, Zhen-Hua; Cao, De-Ying

2010-01-01

To study the prescription and technique of sustained-release dropping pills of curcumin and inspect their release property in vitro. The orthogonal test was used to screen the prescription and technique which were definited with the colligation evaluation of release and formation of dropping pills. The optimization of prescription and technique were as follows: stearic acid 70 mg, glycery monostearate 25 mg, solutol 6 mg, viscosity of cooling liquid was 100 mm2/s; the temperature of material liquid was 80 degrees C; the cooling temperature was 30 - 0 degrees C; the dropping speed was (21 +/- 2) dripping/min. The release behavior of sustained-release dropping pills of curcumin coincidented with Higuchi equation well and the character of sustained-release was transparent. The sustained-release dropping pills of curcumin have good property of sustained-release in vitro and their release behavior in vivo need to be inspected.

Thermal oxidative degradation of wood modified with aminophenylborates

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Klyachenkova Olga

2016-01-01

Full Text Available Comparative thermal analysis in the presence of oxygen was carried out for samples of native pine wood and wood samples modified with aminophenylborates. Significant decrease in the amount of heat released during thermal decomposition of the modified samples was established, which is due to the increase of carbonaceous residues on the surface. Reduction of heat release during decomposition of the modified samples may be explained by the lower yield of combustible volatile products as well as by thin film of boron oxide, formed on the surface of the modified wood, that partially reflects heat flow. Produced upon the modifier decomposition water vapor and inert nitrogen oxides dilute gaseous mixture near the wood surface and isolate it from oxygen. This enhances fire-resistance of wood modified with mono- and diethanolamine(N→Bphenylborates. Hydroxyl group at the sixth carbon atom of the glucopyranose ring of cellulose participates in reactions of cellulose modification, which prevents formation of flammable levoglucosan and, consequently, improves the fire-resistance of the modified wood.

Controlled release of bupivacaine using hybrid thermoresponsive nanoparticles activated via photothermal heating.

Science.gov (United States)

Alejo, Teresa; Andreu, Vanesa; Mendoza, Gracia; Sebastian, Victor; Arruebo, Manuel

2018-08-01

Near-infrared (NIR) responsive nanoparticles are of great interest in the biomedical field as antennas for photothermal therapy and also as triggers for on-demand drug delivery. The present work reports the preparation of hollow gold nanoparticles (HGNPs) with plasmonic absorption in the NIR region covalently bound to a thermoresponsive polymeric shell that can be used as an on-demand drug delivery system for the release of analgesic drugs. The photothermal heating induced by the nanoparticles is able to produce the collapse of the polymeric shell thus generating the release of the local anesthetic bupivacaine in a spatiotemporally controlled way. Those HGNPs contain a 10 wt.% of polymer and present excellent reversible heating under NIR light excitation. Bupivacaine released at physiological temperature (37 °C) showed a pseudo-zero order release that could be spatiotemporally modified on-demand after applying several pulses of light/temperature above and below the lower critical solution temperature (LCST) of the polymeric shell. Furthermore, the nanomaterials obtained did not displayed detrimental effects on four mammalian cell lines at doses up to 0.2 mg/mL. From the results obtained it can be concluded than this type of hybrid thermoresponsive nanoparticle can be used as an externally activated on-demand drug delivery system. Copyright © 2018 Elsevier Inc. All rights reserved.

Biological Phosphorus Release and Uptake Under Alternating Anaerobic and Anoxic Conditions In a Fixed-Film Reactor

DEFF Research Database (Denmark)

Kerrn-Jespersen, Jens Peter; Henze, Mogens; Strube, Rune

1994-01-01

Biological phosphorus removal was investigated in a fixed-film reactor with alternating anaerobic and anoxic conditions. The tests showed that biological phosphorus removal can be obtained in a fixed-film reactor with nitrate as oxidising agent. In the anaerobic period, 0.52 mg of PO4-P...... was released per mg of acetate taken up on an average. In the anoxic period, 2.0 mg of PO4-P was taken up per mg of NO3-N reduced on an average. The relationship between potassium released and phosphate released in the anaerobic phase was determined to be 0.37 mg K/mg P, while the relationship between...

Encapsulation of naproxen in lipid-based matrix microspheres: characterization and release kinetics.

Science.gov (United States)

Bhoyar, P K; Morani, D O; Biyani, D M; Umekar, M J; Mahure, J G; Amgaonkar, Y M

2011-04-01

The objective of this study was to microencapsulate the anti-inflammatory drug (naproxen) to provide controlled release and minimizing or eliminating local side effect by avoiding the drug release in the upper gastrointestinal track. Naproxen was microencapsulated with lipid-like carnauba wax, hydrogenated castor oil using modified melt dispersion (modified congealable disperse phase encapsulation) technique. Effect of various formulation and process variables such as drug-lipid ratio, concentration of modifier, concentration of dispersant, stirring speed, stirring time, temperature of external phase, on evaluatory parameters such as size, entrapment efficiency, and in vitro release of naproxen were studied. The microspheres were characterized for particle size, scanning electron microscopy (SEM), FT-IR spectroscopy, drug entrapment efficiency, in vitro release studies, for in vitro release kinetics. The shape of microspheres was found to be spherical by SEM. The drug entrapment efficiency of various batches of microspheres was found to be ranging from 60 to 90 %w/w. In vitro drug release studies were carried out up to 24 h in pH 7.4 phosphate buffer showing 50-65% drug release. In vitro drug release from all the batches showed better fitting with the Korsmeyer-Peppas model, indicating the possible mechanism of drug release to be by diffusion and erosion of the lipid matrix.

Phosphorus Solubilizing and Releasing Bacteria Screening from the Rhizosphere in a Natural Wetland

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Ying Cao

2018-02-01

Full Text Available Inorganic phosphorus (P-solubilizing bacteria (IPSB and organic P-mineralizing bacteria (OPMB were isolated from bacteria that were first extracted from the rhizosphere soil of a natural wetland and then grown on either tricalcium phosphate or lecithin medium. The solubilizing of inorganic P was the major contribution to P availability, since the isolated bacteria released much more available P from inorganic tricalcium phosphate than lecithin. IPSB No. 5 had the highest P release rate, that is, 0.53 mg·L−1·h−1 in 96 h, and R10′s release rate was 0.52 mg·L−1·h−1 in 10 days. The bacteria were identified as Pseudomonas sp. and Pseudomonas knackmussii, respectively. R10 released as much as 125.88 mg·L−1 dissolved P from tricalcium phosphate medium, while R4 released the most dissolved P from organic P medium among the isolates, with a concentration of 1.88 mg·L−1 and a releasing rate of 0.0078 mg·L−1·h−1 in ten days. P releasing increased with a pH decrease only when it was from inorganic P, not organic lecithin, and there was no significant correlation between the culture pH and P solubilizing. High-throughput sequencing analysis revealed that the dominant phylum in the studied wetland rhizosphere consisted of Acidobacteria, Proteobacteria, Bacteroidetes and Chloroflexi, accounting for 34.9%, 34.2%, 8.8% and 4.8%, respectively.

A randomized comparison of daunorubicin 90 mg/m2 vs 60 mg/m2 in AML induction

DEFF Research Database (Denmark)

Burnett, A. K.; Russell, N. H.; Hills, R. K.

2015-01-01

Modifying induction therapy in acute myeloid leukemia (AML) may improve the remission rate and reduce the risk of relapse, thereby improving survival. Escalation of the daunorubicin dose to 90 mg/m(2) has shown benefit for some patient subgroups when compared with a dose of 45 mg/m(2), and has been...... = .15). In an exploratory subgroup analysis, there was no subgroup that showed significant benefit, although there was a significant interaction by FLT3 ITD mutation. This trial is registered at http://www.isrctn.com as #ISRCTN55675535....

Antibacterial biodegradable Mg-Ag alloys

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D Tie

2013-06-01

Full Text Available The use of magnesium alloys as degradable metals for biomedical applications is a topic of ongoing research and the demand for multifunctional materials is increasing. Hence, binary Mg-Ag alloys were designed as implant materials to combine the favourable properties of magnesium with the well-known antibacterial property of silver. In this study, three Mg-Ag alloys, Mg2Ag, Mg4Ag and Mg6Ag that contain 1.87 %, 3.82 % and 6.00 % silver by weight, respectively, were cast and processed with solution (T4 and aging (T6 heat treatment.The metallurgical analysis and phase identification showed that all alloys contained Mg4Ag as the dominant β phase. After heat treatment, the mechanical properties of all Mg-Ag alloys were significantly improved and the corrosion rate was also significantly reduced, due to presence of silver. Mg(OH2 and MgO present the main magnesium corrosion products, while AgCl was found as the corresponding primary silver corrosion product. Immersion tests, under cell culture conditions, demonstrated that the silver content did not significantly shift the pH and magnesium ion release. In vitro tests, with both primary osteoblasts and cell lines (MG63, RAW 264.7, revealed that Mg-Ag alloys show negligible cytotoxicity and sound cytocompatibility. Antibacterial assays, performed in a dynamic bioreactor system, proved that the alloys reduce the viability of two common pathogenic bacteria, Staphylococcus aureus (DSMZ 20231 and Staphylococcus epidermidis (DSMZ 3269, and the results showed that the killing rate of the alloys against tested bacteria exceeded 90%. In summary, biodegradable Mg-Ag alloys are cytocompatible materials with adjustable mechanical and corrosion properties and show promising antibacterial activity, which indicates their potential as antibacterial biodegradable implant materials.

Controlled drug release on amine functionalized spherical MCM-41

International Nuclear Information System (INIS)

Szegedi, Agnes; Popova, Margarita; Goshev, Ivan; Klébert, Szilvia; Mihály, Judit

2012-01-01

MCM-41 silica with spherical morphology and small particle sizes (100 nm) was synthesized and modified by post-synthesis method with different amounts of 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, was carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N 2 physisorption, elemental analysis, thermal analysis and FT-IR spectroscopy. A new method was developed for the quantitative determination of amino groups in surface modified mesoporous materials by the ninhydrin reaction. Good correlation was found between the amino content of the MCM-41 materials determined by the ninhydrin method and their ibuprofen adsorption capacity. Amino modification resulted in high degree of ibuprofen loading and slow release rate in comparison to the parent non-modified MCM-41. - Graphical abstract: Determination of surface amino groups by ninhidrin method. Highlights: ► Spherical MCM-41 modified by different amounts of APTES was studied. ► Ibuprofen (IBU) adsorption and release characteristics was tested. ► The ninhydrin reaction was used for the quantitative determination of amino groups. ► Stoichiometric amount of APTES is enough for totally covering the surface with amino groups. ► Good correlation was found between the amino content and IBU adsorption capacity.

Surface modification of parylene-N films for the culture of osteoblast-like cells (MG-63)

Energy Technology Data Exchange (ETDEWEB)

Liaqat, Usman [Graduate Program of Nano Science and Technology, Yonsei University, 50-Yonsei Ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Ko, Hyuk [Department of Materials Science and Engineering, Yonsei University, 50-Yonsei Ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Suh, Hwal [Graduate Program of Nano Science and Technology, Yonsei University, 50-Yonsei Ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of); Department of Medical Engineering, College of Medicine, Yonsei University, 50-Yonsei Ro, Seodaemun-gu, Seoul, 120-749 (Korea, Republic of); Lee, Misu [Division of Life Sciences, College of Life Science and Bioengineering, Incheon National University, Incheon 406-772 (Korea, Republic of); Pyun, Jae-Chul, E-mail: jcpyun@yonsei.ac.kr [Department of Materials Science and Engineering, Yonsei University, 50-Yonsei Ro, Seodaemun-gu, Seoul 120-749 (Korea, Republic of)

2016-08-15

Highlights: • Osteoblast-like cells (MG-63) was cultured on differently modified surfaces of parylene films. • Proliferation of MG-63 was observed to be far increased on UV-treated parylene-N film. • The influences of UV-treatment were found out on cell viability, proliferation rate and cell cycle. • The influence was estimated to be negligible on the protein synthesis, cell differentiation. • The UV-treated parylene-N was demonstrated to be effectively used for the culture of MG-63. - Abstract: The influence of microenvironments on the culture of osteoblast-like cells (MG-63) has been investigated using parylene films with different surfaces, such as parylene-N film, UV-modified parylene-N film, functional parylene film with amine groups (parylene-A), and UV-modified parylene-A film. In this work, parylene-N film was found to induce dramatic changes in cell adhesion and cell viability before and after UV-treatment with respect to the culture of osteoblast-like cells (MG-63). The influences of such a chemical environment on cell culture were investigated in relation to the cell proliferation (viability and proliferation rate) and the cell physiology (cell cycle, protein synthesis, and differentiation) of cells grown on parylene-N film, UV-modified parylene-N film, parylene-A film, and UV-modified parylene-A film in comparison with cells grown on a polystyrene surface.

Design and in vivo evaluation of oxycodone once-a-day controlled-release tablets

Directory of Open Access Journals (Sweden)

Kim JY

2015-01-01

Full Text Available Ju-Young Kim,1,* Sung-Hoon Lee,2,3,* Chun-Woong Park,4 Yun-Seok Rhee,5 Dong-Wook Kim,6 Junsang Park,3 Moonseok Lee,3 Jeong-Woong Seo,2 Eun-Seok Park2 1College of Pharmacy, Woosuk University, Wanju-gun, Republic of Korea; 2School of Pharmacy, Sungkyunkwan University, Suwon, Republic of Korea; 3GL Pharmtech, Seongnam, Republic of Korea; 4College of Pharmacy, Chungbuk National University, Cheongju, Republic of Korea; 5College of Pharmacy and Research Institute of Pharmaceutical Sciences, Gyeongsang National University, Jinju, Republic of Korea; 6Department of Pharmaceutical Engineering, Cheongju University, Cheongju, Republic of Korea *These authors contributed equally to this work Abstract: The aim of present study was to design oxycodone once-a-day controlled-release (CR tablets and to perform in vitro/in vivo characterizations. Release profiles to achieve desired plasma concentration versus time curves were established by using simulation software and reported pharmacokinetic parameters of the drug. Hydroxypropyl methylcellulose (HPMC 100,000 mPa·s was used as a release modifier because the polymer was found to be resistant to changes in conditions of the release study, including rotation speed of paddle and ion strength. The burst release of the drug from the CR tablets could be suppressed by applying an additional HPMC layer as a physical barrier. Finally, the oxycodone once-a-day tablet was comprised of two layers, an inert HPMC layer and a CR layer containing drug and HPMC. Commercial products, either 10 mg bis in die (bid [twice a day] or once-a-day CR tablets (20 mg were administered to healthy volunteers, and calculated pharmacokinetic parameters indicated bioequivalence of the two different treatments. The findings of the present study emphasize the potential of oxycodone once-a-day CR tablets for improved patient compliance, safety, and efficacy, which could help researchers to develop new CR dosage forms of oxycodone. Keywords

Controlled antiseptic/eosin release from chitosan-based hydrogel modified fibrous substrates.

Science.gov (United States)

Romano, Ilaria; Ayadi, Farouk; Rizzello, Loris; Summa, Maria; Bertorelli, Rosalia; Pompa, Pier Paolo; Brandi, Fernando; Bayer, Ilker S; Athanassiou, Athanassia

2015-10-20

Fibers of cellulose networks were stably coated with N-methacrylate glycol chitosan (MGC) shells using subsequent steps of dip coating and photo-curing. The photo-crosslinked MGC-coated cellulose networks preserved their fibrous structure. A model hydrophilic antiseptic solution containing eosin, chloroxylenol and propylene glycol was incorporated into the shells to study the drug release dynamics. Detailed drug release mechanism into phosphate buffered saline (PBS) solutions from coated and pristine fibers loaded with the antiseptic was investigated. The results show that the MGC-coated cellulose fibers enable the controlled gradual release of the drug for four days, as opposed to fast, instantaneous release from eosin coated pristine fibers. This release behavior was found to affect the antibacterial efficiency of the fibrous cellulose sheets significantly against Staphylococcus aureus and Candida albicans. In the case of the MGC-eosin functionalized system the antibacterial efficiency was as high as 85% and 90%, respectively, while for the eosin coated pristine cellulose system the efficiency was negative, indicating bacterial proliferation. Furthermore, the MGC-eosin system was shown to be efficacious in a model of wound healing in mice, reducing the levels of various pro-inflammatory cytokines that modulate early inflammatory phase responses. The results demonstrate good potential of these coated fibers for wound dressing and healing applications. Due to its easy application on common passive commercial fibrous dressings such as gauzes and cotton fibers, the method can render them active dressings in a cost effective way. Copyright © 2015. Published by Elsevier Ltd.

Formulation development and optimization of sustained release matrix tablet of Itopride HCl by response surface methodology and its evaluation of release kinetics.

Science.gov (United States)

Bose, Anirbandeep; Wong, Tin Wui; Singh, Navjot

2013-04-01

The objective of this present investigation was to develop and formulate sustained release (SR) matrix tablets of Itopride HCl, by using different polymer combinations and fillers, to optimize by Central Composite Design response surface methodology for different drug release variables and to evaluate drug release pattern of the optimized product. Sustained release matrix tablets of various combinations were prepared with cellulose-based polymers: hydroxy propyl methyl cellulose (HPMC) and polyvinyl pyrolidine (pvp) and lactose as fillers. Study of pre-compression and post-compression parameters facilitated the screening of a formulation with best characteristics that underwent here optimization study by response surface methodology (Central Composite Design). The optimized tablet was further subjected to scanning electron microscopy to reveal its release pattern. The in vitro study revealed that combining of HPMC K100M (24.65 MG) with pvp(20 mg)and use of LACTOSE as filler sustained the action more than 12 h. The developed sustained release matrix tablet of improved efficacy can perform therapeutically better than a conventional tablet.

Gd(III)-DOTA-modified sonosensitive liposomes for ultrasound-triggered release and MR imaging

Science.gov (United States)

Jung, Suk Hyun; Na, Kyunga; Lee, Seul A.; Cho, Sun Hang; Seong, Hasoo; Shin, Byung Cheol

2012-08-01

Ultrasound-sensitive (sonosensitive) liposomes for tumor targeting have been studied in order to increase the antitumor efficacy of drugs and decrease the associated severe side effects. Liposomal contrast agents having Gd(III) are known as a nano-contrast agent system for the efficient and selective delivery of contrast agents into pathological sites. The objective of this study was to prepare Gd(III)-DOTA-modified sonosensitive liposomes (GdSL), which could deliver a model drug, doxorubicin (DOX), to a specific site and, at the same time, be capable of magnetic resonance (MR) imaging. The GdSL was prepared using synthesized Gd(III)-DOTA-1,2-distearoyl- sn-glycero-3-phosphoethanolamine lipid. Sonosensitivity of GdSL to 20-kHz ultrasound induced 33% to 40% of DOX release. The relaxivities ( r 1) of GdSL were 6.6 to 7.8 mM-1 s-1, which were higher than that of MR-bester®. Intracellular uptake properties of GdSL were evaluated according to the intensity of ultrasound. Intracellular uptake of DOX for ultrasound-triggered GdSL was higher than that for non-ultrasound-triggered GdSL. The results of our study suggest that the paramagnetic and sonosensitive liposomes, GdSL, may provide a versatile platform for molecular imaging and targeted drug delivery.

Phase controlled synthesis of (Mg, Ca, Ba)-ferrite magnetic nanoparticles with high uniformity

Energy Technology Data Exchange (ETDEWEB)

Wang, S.F., E-mail: wangshifa2006@yeah.net [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan (China); Science and technology on vacuum technology and physics laboratory, Lanzhou Institute of Physics, Lanzhou 730000, Gansu (China); Li, Q. [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan (China); Zu, X.T., E-mail: xtzu@uestc.edu.cn [Institute of Fundamental and Frontier Sciences, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan (China); Xiang, X.; Liu, W. [School of Physical Electronics, University of Electronic Science and Technology of China, Chengdu 610054, Sichuan (China); Li, S., E-mail: sean.li@unsw.edu.au [School of Material Science and Engineering, University of New South Wales, Sydney 2052 (Australia)

2016-12-01

(Mg, Ca, Ba)-ferrite magnetic nanoparticles were successfully synthesized through modifying the atomic ratio of polysaccharide and chelating agent at an optimal sintering temperature. In the process, the polysaccharide plays an important role in drastically shrinking the precursor during the gel drying process. In the metal-complex structure, M{sup 2+} ion active sites were coordinated by −OH of the water molecules except for EDTA anions. The MFe{sub 2}O{sub 4} magnetic nanoparticles exhibited enhanced magnetic properties when compared with nano-MFe{sub 2}O{sub 4} of similar particle size synthesized by other synthesis route reported in the literature. In particular, the sintering temperature improves the crystallinity and increases the hysteresis loop squareness ratio of (Mg, Ca, Ba)-ferrite nanoparticles significantly. - Graphical abstract: Schematic representation of the proposed model for MFe{sub 2}O{sub 4} nanoparticle synthesis, starting from EDTA-chelated M{sup 2+} (M=Mg, Ca, or Ba) cations (left). High dispersion (Mg, Ca, Ba)-ferrite magnetic nanoparticles were prepared by a modified polyacrylamide gel route. Optimized utilization of polysaccharide, chelating agent, and sintering temperature allowed the formation of (Mg, Ca, Ba)-ferrite nanoparticles with a narrow diameter distribution. - Highlights: • We report a modified polyacrylamide gel route to synthesize (Mg, Ca, Ba)-ferrite magnetic nanoparticles. • Chelate mechanism of metal ions (Mg, Ca, Ba) and EDTA has been discussed. • Phase transformation process of (Mg, Ca, Ba)-ferrites has been discussed. • The preparation method increases the hysteresis loop squareness ratio of (Mg, Ca, Ba)-ferrite nanoparticles.

Detection of Mg spinel lithologies on central peak of crater ...

Indian Academy of Sciences (India)

identified Fe bearing Mg-spinel-rich rock types are defined by their strong 2-μm ... The Modified Gaussian Modeling (MGM) analysis ... study the deep crustal and/or upper mantle composition and may lead to a fresh ... Lunar surface; Mg-spinel; central peak; Theophilus; remote sensing. .... The explanation of these spec-.

In vivo and in vitro degradation comparison of pure Mg, Mg-10Gd and Mg-2Ag: a short term study

Directory of Open Access Journals (Sweden)

I Marco

2017-02-01

Full Text Available The purpose of this study was to compare short term in vitro and in vivo biodegradation studies with low purity Mg (> 99.94 %, Mg-10Gd and Mg-2Ag designed for biodegradable implant applications. Three in vitro testing conditions were applied, using (i phosphate buffered saline (PBS, (ii Hank’s balanced salt solution (HBSS and (iii Dulbecco’s modified eagle medium (DMEM in 5 % CO2 under sterile conditions. Gas evolution and mass loss (ML were assessed, as well as the degradation layer, by elemental mapping and scanning electron microscopy (SEM. In vivo, implantations were performed on male Sprague-Dawley rats evaluating both, gas cavity volume and implant volume reduction by micro-computed tomography (µCT, 7 d after implantation. Samples were produced by casting, solution heat treatment and extrusion in disc and pin shape for the in vitro and in vivo experiments, respectively. Results showed that when the processing of the Mg sample varied, differences were found not only in the alloy impurity content and the grain size, but also in the corrosion behaviour. An increase of Fe and Ni or a large grain size seemed to play a major role in the degradation process, while the influence of alloying elements, such as Gd and Ag, played a secondary role. Results also indicated that cell culture conditions induced degradation rates and degradation layer elemental composition comparable to in vivo conditions. These in vitro and in vivo degradation layers consisted of Mg hydroxide, Mg-Ca carbonate and Ca phosphate.

Increasing kynurenine brain levels reduces ethanol consumption in mice by inhibiting dopamine release in nucleus accumbens.

Science.gov (United States)

Giménez-Gómez, Pablo; Pérez-Hernández, Mercedes; Gutiérrez-López, María Dolores; Vidal, Rebeca; Abuin-Martínez, Cristina; O'Shea, Esther; Colado, María Isabel

2018-06-01

Recent research suggests that ethanol (EtOH) consumption behaviour can be regulated by modifying the kynurenine (KYN) pathway, although the mechanisms involved have not yet been well elucidated. To further explore the implication of the kynurenine pathway in EtOH consumption we inhibited kynurenine 3-monooxygenase (KMO) activity with Ro 61-8048 (100 mg/kg, i.p.), which shifts the KYN metabolic pathway towards kynurenic acid (KYNA) production. KMO inhibition decreases voluntary binge EtOH consumption and EtOH preference in mice subjected to "drinking in the dark" (DID) and "two-bottle choice" paradigms, respectively. This effect seems to be a consequence of increased KYN concentration, since systemic KYN administration (100 mg/kg, i.p.) similarly deters binge EtOH consumption in the DID model. Despite KYN and KYNA being well-established ligands of the aryl hydrocarbon receptor (AhR), administration of AhR antagonists (TMF 5 mg/kg and CH-223191 20 mg/kg, i.p.) and of an agonist (TCDD 50 μg/kg, intragastric) demonstrates that signalling through this receptor is not involved in EtOH consumption behaviour. Ro 61-8048 did not alter plasma acetaldehyde concentration, but prevented EtOH-induced dopamine release in the nucleus accumbens shell. These results point to a critical involvement of the reward circuitry in the reduction of EtOH consumption induced by KYN and KYNA increments. PNU-120596 (3 mg/kg, i.p.), a positive allosteric modulator of α7-nicotinic acetylcholine receptors, partially prevented the Ro 61-8048-induced decrease in EtOH consumption. Overall, our results highlight the usefulness of manipulating the KYN pathway as a pharmacological tool for modifying EtOH consumption and point to a possible modulator of alcohol drinking behaviour. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mg substituted apatite coating from alkali conversion of acidic calcium phosphate

Energy Technology Data Exchange (ETDEWEB)

Navarro da Rocha, Daniel, E-mail: dnr.navarro@gmail.com [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Cruz, Leila Rosa de Oliveira [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Campos, José Brant de [Rio de Janeiro State University - UERJ, Rio de Janeiro, R.J. (Brazil); Marçal, Rubens L. Santana Blazutti [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil); Mijares, Dindo Q.; Coelho, Paulo G. [Department of Biomaterials and Biomimetics, New York University College of Dentistry (NYU), New York, NY (United States); Prado da Silva, Marcelo H. [Military Institute of Engineering-IME, Pça. Gen. Tiburcio, 80, P. Vermelha, Urca, Rio de Janeiro, R.J. (Brazil)

2017-01-01

In this work, two solutions were developed: the first, rich in Ca{sup 2+}, PO{sub 4}{sup 3−} ions and the second, rich in Ca{sup 2+}, PO{sub 4}{sup 3−} and Mg{sup 2+}, defined as Mg-modified precursor solution. For each Mg-modified precursor solution, the concentrations of Mg{sup 2+} ions were progressively increased by 5%, 10% and 15%wt. The aims of this research were to investigate the influence of magnesium ions substitution in calcium phosphate coatings on titanium surface and to evaluate these coatings by bioactivity assay in McCoy culture medium. The obtained coatings were characterized by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis, and the presence of Mg ions was confirmed by the inductively coupled plasma atomic emission spectroscopy (ICP) analysis. In vitro bioactivity assay in McCoy culture medium showed bioactivity after 14 days in incubation for the HA and 10% Mg-monetite coatings. The high chemical stability of Mg-HA coatings was verified by the bioactivity assays, and no bone-like apatite deposition, characteristic of bioactivity, was observed for Mg-HA coatings, for the time period used in this study. - Highlights: • The presence of Mg ions influenced the final apatite phase present in the produced coatings. • A lower efficiency in heterogeneous deposition and an exposure of Ti substrate in 5% Mg-monetite coatings was soon verified. • McCoy culture medium was effective in predicting the coatings bioactivity.

Formulation of Dipyridamole Sustained Release Tablet Using Floating System

Directory of Open Access Journals (Sweden)

Lenny Mauilida Valentina

2011-06-01

Full Text Available Dipyridamole is a drug for prevention of postoperative thromboembolic complication of heart valve replacement and long term therapy of angina pectoris will be well absorbed in stomach. To maintain therapeutic plasma concentration in long time and to increase bioavalaibility is needed a sustained release dosage form having the long residence time in the stomach. The objective of this research was to make floating sustained release tablet of dipyridamole conforming to the requirement that was set up by dipyridamol therapeutic concentration. Tablets were made by wet granulation method using aquadest as a liquid binder, HPMC K4M, Ac-di-sol, Avicel PH 102, talk, and Mg stearat. Dissolution assay was carried out using type 2 release tester at rotation speed of 50 rpm in medium 900 mL HCl 0.1 N at 37 ± 0.5 °C for 8 hours. The formulation containing of 50 mg dipirydamole, HPMC K4M (30%, Ac-di-sol (20%, Avicel PH 102 (37%, talk (2%, and Mg stearat (1% released 59.61 ± 6.73% and 89.34 ± 5.87% of dipyridamole respectively after 4 and 8 hours that conformed to the requirement.

Building an Efficient Model for Afterburn Energy Release

Energy Technology Data Exchange (ETDEWEB)

Alves, S; Kuhl, A; Najjar, F; Tringe, J; McMichael, L; Glascoe, L

2012-02-03

Many explosives will release additional energy after detonation as the detonation products mix with the ambient environment. This additional energy release, referred to as afterburn, is due to combustion of undetonated fuel with ambient oxygen. While the detonation energy release occurs on a time scale of microseconds, the afterburn energy release occurs on a time scale of milliseconds with a potentially varying energy release rate depending upon the local temperature and pressure. This afterburn energy release is not accounted for in typical equations of state, such as the Jones-Wilkins-Lee (JWL) model, used for modeling the detonation of explosives. Here we construct a straightforward and efficient approach, based on experiments and theory, to account for this additional energy release in a way that is tractable for large finite element fluid-structure problems. Barometric calorimeter experiments have been executed in both nitrogen and air environments to investigate the characteristics of afterburn for C-4 and other materials. These tests, which provide pressure time histories, along with theoretical and analytical solutions provide an engineering basis for modeling afterburn with numerical hydrocodes. It is toward this end that we have constructed a modified JWL equation of state to account for afterburn effects on the response of structures to blast. The modified equation of state includes a two phase afterburn energy release to represent variations in the energy release rate and an afterburn energy cutoff to account for partial reaction of the undetonated fuel.

Perbandingan Pengaruh Nifedipin 20 mg per Oral 2 Jam Preoperasi dengan Plasebo terhadap Suhu Inti pada Pasien yang Menjalani Operasi Modified Radical Mastectomy dengan Anestesi Umum

Directory of Open Access Journals (Sweden)

Saleh Trisnadi

2014-08-01

Full Text Available Strategy of prevention the initial redistribution hypothermia is based on the reduction of the heat gradient between the core and perifer before surgery by administering vasodilators. The purpose of this study was to asses the effect of oral nifedipine 20 mg 2 hours before anesthesia in preventing hypothermia in patients undergoing modified radical mastectomy under general anesthesia and to compare the decreased rate of body temperature oral nifedipine with placebo. The research was done with the prospective method, randomized double-blind controlled study in 30 patients aged 18–60 yrs, American Society of Anesthesiologist (ASA physical status I-II, underwent modified radical mastectomy surgery, were randomly divided into two groups at Dr. Hasan Sadikin General Hospital Bandung during June until August 2012. One group was given oral nifedipine 20 mg 2 hours before general anesthesia and the other group was given placebo. Tymphani temperature was recorded during anesthesia every 10 minutes. Research data was tested statistically by the Mann-Whitney test. The average core temperature in the nifedipine was 36.37 ° C which was higher than the control group 35.61 ° C (p<0.05. It can be concluded that the use of nifedipine can prevent intraoperative hypothermia.

Depth preference in released juvenile turbot Psetta maxima

DEFF Research Database (Denmark)

Albertsen, Christoffer Moesgaard; Støttrup, Josianne; Nielsen, Anders

2014-01-01

Hatchery-reared juvenile turbot Psetta maxima were tagged with Passive Integrated Transponder (PIT) tags and released at three different depths in a sandy bay in Denmark. About 2–7% of the released fish were registered daily to monitor their distribution using a tag antenna mounted on a modified...

Controlled drug release on amine functionalized spherical MCM-41

Energy Technology Data Exchange (ETDEWEB)

Szegedi, Agnes, E-mail: szegedi@chemres.hu [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary); Popova, Margarita; Goshev, Ivan [Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia (Bulgaria); Klebert, Szilvia [Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary); Mihaly, Judit [Institute of Molecular Pharmacology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1025 Budapest, Pusztaszeri ut 59-67 (Hungary)

2012-10-15

MCM-41 silica with spherical morphology and small particle sizes (100 nm) was synthesized and modified by post-synthesis method with different amounts of 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, was carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N{sub 2} physisorption, elemental analysis, thermal analysis and FT-IR spectroscopy. A new method was developed for the quantitative determination of amino groups in surface modified mesoporous materials by the ninhydrin reaction. Good correlation was found between the amino content of the MCM-41 materials determined by the ninhydrin method and their ibuprofen adsorption capacity. Amino modification resulted in high degree of ibuprofen loading and slow release rate in comparison to the parent non-modified MCM-41. - Graphical abstract: Determination of surface amino groups by ninhidrin method. Highlights: Black-Right-Pointing-Pointer Spherical MCM-41 modified by different amounts of APTES was studied. Black-Right-Pointing-Pointer Ibuprofen (IBU) adsorption and release characteristics was tested. Black-Right-Pointing-Pointer The ninhydrin reaction was used for the quantitative determination of amino groups. Black-Right-Pointing-Pointer Stoichiometric amount of APTES is enough for totally covering the surface with amino groups. Black-Right-Pointing-Pointer Good correlation was found between the amino content and IBU adsorption capacity.

Si-modified BHA bioceramics as a drug delivery system: Effect of modification method on structure and Rifampicin release

Directory of Open Access Journals (Sweden)

Olena Sych

2015-09-01

Full Text Available The work is devoted to the investigation of two different methods for introduction of silicon into ceramics, based on biogenic hydroxyapatite (BHA, on the structure and properties. Thus, porous samples of Si-modified BHA-based ceramics containing 2 or 5 wt.% Si were prepared by using two different precursors, i.e. polymethylsiloxane polyhydrate and fine silica (Aerosil® 200 powder. After the modification with silicon a marked change in the structure of material was observed. The use of Aerosil® 200 permits preparation of a more uniform structure as compared to that obtained by using polymethylsiloxane polyhydrate. However, the latter promotes an increase in both the porosity of samples (from 43 to 62.3% and their solubility in saline (from 0.18 to 1.20 wt.%/day as compared to the results obtained after the modification with Aerosil® 200, where maximal porosity and solubility were 48.5% and 0.23 wt.%/day, respectively. At the same time, the modification of hydroxyapatite ceramics with silicon using silica makes it possible to prolong release of a drug (e.g. Rifampicin out of sample pores for the first 24 h as compared to the ceramics modified with polymethylsiloxane polyhydrate.

Effect of food on early drug exposure from extended-release stimulants: results from the Concerta, Adderall XR Food Evaluation (CAFE) Study.

Science.gov (United States)

Auiler, J F; Liu, K; Lynch, J M; Gelotte, C K

2002-01-01

Stimulant therapy is the mainstay of treatment for children, adolescents and adults with attention-deficit/hyperactivity disorder (ADHD). Once-daily, extended-release oral formulations offer long acting control of symptoms by modifying drug delivery and absorption. In particular, consistency in early drug exposure is important for symptom control during school or work hours. Because these once-daily formulations are usually taken in the morning, the timing of the doses with breakfast is important. This study compared the effect of a high-fat breakfast on early drug exposure from a morning dose of two extended-release stimulant formulations: the osmotic-controlled OROS tablet of methylphenidate HCI (CONCERTA) and the capsule containing extended-release beads of mixed amphetamine salts (ADDERALL XR). The study had a single-dose, open-label, randomised, four-treatment, crossover design in which healthy subjects received either 36 mg CONCERTA or 20 mg ADDERALL XR in the morning after an overnight fast or a high-fat breakfast. Serial blood samples were collected over 28h to determine plasma concentrations of methylphenidate and amphetamine. The food effect on early drug exposure and the pharmacokinetic profiles up to 8 h after dosing of the two extended-release stimulants were directly compared using partial area (AUC(p4h), AUC(p6h) and AUC(p8h)) fed/fasted ratios. Amphetamine concentrations were markedly lower when the subjects had eaten breakfast, resulting in lower early drug exposures (p food, for patients with ADHD.

Formulation and evaluation of rifampicin sustained release tablets using juice of Citrus limetta as bio-retardant.

Science.gov (United States)

Gaur, K Pawan; Soam, Kulwant; Gupta, S K; Dabral, Prashant

2012-03-01

The advantages of biopolymers over synthetic polymers are low cost, natural origin, free from side effects, biocompatible, bio-acceptable, environmental friendly processing, local availability, better patient tolerance as well as public acceptance. Sustained release tablets containing rifampicin was prepared by adding 100 mg polymer and 50 mg Drug and Granules. Same procedure was followed with 3% and 5% of polymer for preparation of sustained release tablets. Additional Tablets of 100 mg, 200 mg and 400 mg were prepared using 5% of the polymer. The results indicated that the selected biopolymer had a good release retardant property thus it can be concluded that the selected biopolymer can be utilized as low cost natural biocompatible and biodegradable agent.

Formulation and evaluation of rifampicin sustained release tablets using juice of Citrus limetta as bio-retardant

Directory of Open Access Journals (Sweden)

K Pawan Gaur

2012-01-01

Full Text Available The advantages of biopolymers over synthetic polymers are low cost, natural origin, free from side effects, biocompatible, bio-acceptable, environmental friendly processing, local availability, better patient tolerance as well as public acceptance. Sustained release tablets containing rifampicin was prepared by adding 100 mg polymer and 50 mg Drug and Granules. Same procedure was followed with 3% and 5% of polymer for preparation of sustained release tablets. Additional Tablets of 100 mg, 200 mg and 400 mg were prepared using 5% of the polymer. The results indicated that the selected biopolymer had a good release retardant property thus it can be concluded that the selected biopolymer can be utilized as low cost natural biocompatible and biodegradable agent.

Development of analysis methodology for hot leg break mass and energy release

International Nuclear Information System (INIS)

Song, Jin Ho; Kim, Cheol Woo; Kwon, Young Min; Kim, Sook Kwan

1995-04-01

A study for the development of an analysis methodology for hot leg break mass and energy release is performed. For the blowdown period a modified CEFLASH-4A methodology is suggested. For the post blowdown period a modified CONTRAST boil-off model is suggested. By using these computer code improved mass and energy release data are generated. Also, a RELAP5/MOD3 analysis for finally the FLOOD-3 computer code has been modified for use in the analysis of hot leg break. The results of analysis using modified FLOOD-3 are reasonable as we expected and their trends are good. 66 figs., 8 tabs. (Author) .new

Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

International Nuclear Information System (INIS)

Li, Shuo; Bhushan, Bharat

2016-01-01

Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

Lubrication performance and mechanisms of Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxide nanoparticles as lubricant additives

Energy Technology Data Exchange (ETDEWEB)

Li, Shuo [School of Materials Science and Technology, China University of Geosciences (Beijing), 29 Xueyuan Road, Haidian Distract, Beijing 100083 (China); Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States); Bhushan, Bharat, E-mail: bhushan.2@osu.edu [Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLBB), The Ohio State University, 201 W. 19th Avenue Columbus, OH 43210-1142 (United States)

2016-08-15

Highlights: • Mg/Al-, Zn/Al- and Zn/Mg/Al-layered double hydroxide were synthesized. • Mg/Al-LDH had superior tribological performance compared to other LDHs. • The best thermal stability of Mg/Al-LDH was responsible for its friction property. - Abstract: Solid lubricant particles are commonly used as oil additives for low friction and wear. Mg/Al-, Zn/Al-, and Zn/Mg/Al-layered double hydroxides (LDH) were synthesized by coprecipitation method. The benefits of LDH nanoparticles are that they can be synthesized using chemical methods where size and shape can be controlled, and can be modified organically to allow dispersal in fluids. The LDH nanoparticles were characterized by X-ray diffraction, scanning electron microscope, thermogravimetry, and differential scanning calorimetry. A pin-on-disk friction and wear tester was used for evaluating the friction and wear properties of LDH nanoparticles as lubricant additives. LDH nanoparticles have friction-reducing and anti-wear properties compared to oil without LDHs. Mg/Al-LDH has the best lubrication, possibly due to better thermal stability in severe conditions.

Osteoblast cell response to surface-modified carbon nanotubes

International Nuclear Information System (INIS)

Zhang Faming; Weidmann, Arne; Nebe, J. Barbara; Burkel, Eberhard

2012-01-01

In order to investigate the interaction of cells with modified multi-walled carbon nanotubes (MWCNTs) for their potential biomedical applications, the MWCNTs were chemically modified with carboxylic acid groups (–COOH), polyvinyl alcohol (PVA) polymer and biomimetic apatite on their surfaces. Additionally, human osteoblast MG-63 cells were cultured in the presence of the surface-modified MWCNTs. The metabolic activities of osteoblastic cells, cell proliferation properties, as well as cell morphology were studied. The surface modification of MWCNTs with biomimetic apatite exhibited a significant increase in the cell viability of osteoblasts, up to 67.23%. In the proliferation phases, there were many more cells in the biomimetic apatite-modified MWCNT samples than in the MWCNTs–COOH. There were no obvious changes in cell morphology in osteoblastic MG-63 cells cultured in the presence of these chemically-modified MWCNTs. The surface modification of MWCNTs with apatite achieves an effective enhancement of their biocompatibility.

A comparison of N-methyl-D-aspartate-evoked release of adenosine and [3H]norepinephrine from rat cortical slices

International Nuclear Information System (INIS)

Hoehn, K.; Craig, C.G.; White, T.D.

1990-01-01

Tetrodotoxin reduced N-methyl-D-aspartate (NMDA)-evoked release of adenosine by 35% but virtually abolished [3H]norepinephrine release. Although [3H]norepinephrine release from rat cortical slices evoked by 500 microM NMDA was abolished by 1.2 mM Mg++, which produces a voltage-sensitive, uncompetitive block of NMDA-channels, adenosine release was increased in the presence of Mg++. Partial depolarization with 12 mM K+ relieved the Mg++ block of 500 microM NMDA-evoked [3H]norepinephrine release but did not affect adenosine release, indicating that a Mg++ requirement for the adenosine release process per se cannot account for this discrepancy. NMDA was 33 times more potent in releasing adenosine than [3H]norepinephrine. At submaximal concentrations of NMDA (10 and 20 microM), adenosine release was augmented in Mg+(+)-free medium. Although a high concentration of the uncompetitive NMDA antagonist MK-801 [(+)-5-methyl-10,11,dihydro-5H-dibenzo[a,d]cyclohepten-5-10-imine maleate] (3 microM) blocked NMDA-evoked release of [3H]norepinephrine and adenosine, a lower concentration (300 nM) decreased NMDA-evoked [3H]norepinephrine release by 66% without affecting adenosine release. These findings suggest that maximal adenosine release occurs when relatively few NMDA receptors are activated, raising the possibility that spare receptors exist for NMDA-evoked adenosine release. Rather than acting as a protectant against excessive NMDA excitation, released adenosine might provide an inhibitory threshold which must be overcome for NMDA-mediated neurotransmission to proceed

Removing Phosphorus from Aqueous Solutions Using Lanthanum Modified Pine Needles.

Directory of Open Access Journals (Sweden)

Xianze Wang

Full Text Available The renewable pine needles was used as an adsorbent to remove phosphorus from aqueous solutions. Using batch experiments, pine needles pretreated with alkali-isopropanol (AI failed to effectively remove phosphorus, while pine needles modified with lanthanum hydroxide (LH showed relatively high removal efficiency. LH pine needles were effective at a wide pH ranges, with the highest removal efficiency reaching approximately 85% at a pH of 3. The removal efficiency was kept above 65% using 10 mg/L phosphorus solutions at desired pH values. There was no apparent significant competitive behavior between co-existing anions of sulfate, nitrate, and chloride (SO4(2-, NO3(- and Cl(-; however, CO3(2- exhibited increased interfering behavior as concentrations increased. An intraparticle diffusion model showed that the adsorption process occurred in three phases, suggesting that a boundary layer adsorption phenomena slightly affected the adsorption process, and that intraparticle diffusion was dominant. The adsorption process was thermodynamically unfavorable and non-spontaneous; temperature increases improved phosphorus removal. Total organic carbon (TOC assays indicated that chemical modification reduced the release of soluble organic compounds from 135.6 mg/L to 7.76 mg/L. This new information about adsorption performances provides valuable information, and can inform future technological applications designed to remove phosphorus from aqueous solutions.

Experimental investigation of the reactions 25Mg(α,n)28Si, 26Mg(α,n)29Si, 18O(α,n)21Ne and their impact on stellar nucleosynthesis

International Nuclear Information System (INIS)

Falahat, Sascha

2010-01-01

In the present dissertation, the nuclear reactions 25 Mg(α,n) 28 Si, 26 Mg(α,n) 29 Si, 18 O(α,n) 21 Ne are investigated in the astrophysically interesting energy region from E α =1000 keV to E α =2450 keV. The experiments were performed at the Nuclear Structure Laboratory of the University of Notre Dame (USA) with the Van-de-Graaff accelerator KN. Solid state targets with evaporated magnesium or anodized oxygen were bombarded with α-particles and the released neutrons detected. For the detection of the released neutrons, computational simulations were used to construct a neutron detector based on 3 He counters. Because of the strong occurrence of background reactions, different methods of data analysis were employed. Finally, the impact of the reactions 25 Mg(α,n) 28 Si, 26 Mg(α,n) 29 Si, 18 O(α,n) 21 Ne on stellar nucleosynthesis is investigated by means of network calculations. (orig.)

Poloxamer surface modified trimethyl chitosan nanoparticles for the effective delivery of methotrexate in osteosarcoma.

Science.gov (United States)

Li, Shenglong; Xiong, Yuyuan; Zhang, Xiaojing

2017-06-01

The present work is an effort to explore the poloxamer-modified trimethyl chitosan (TMC) encapsulated MTX for osteosarcoma treatment in order to improve the therapeutic efficacy and minimize severe toxicity associated with the clinical usage of MTX. The methotrexate-loaded pluronic-chitosan nanoparticles (MTCN) was nanosized and exhibited a controlled release of drug from the carrier system. The MTCN showed higher accumulation in cell cytoplasm region evident by the high red fluorescence indicating its uptake through energy-dependent endocytosis process. MTCN exhibited the increased cytotoxicity in MG63 cells compared free MTX due to its enhanced cellular uptake. Especially, MTCN exhibited a superior apoptosis effect with bright chromatin condensation and nuclear fragmentation was observed and showed remarkably higher apoptosis (∼48%) compared to that of free drug. The results of this investigation clearly demonstrate that the poloxamer-modified trimethyl chitosan (TMC) seems to have a great potential as a drug carrier in cancer chemotherapy. The present research work offers immense scope for further exploitation of poloxamer-modified trimethyl chitosan (TMC) in future for the development of nanoparticulate drug delivery system for cancer chemotherapy. Copyright © 2017. Published by Elsevier Masson SAS.

Sr, Mg cosubstituted HA porous macro-granules: potentialities as resorbable bone filler with antiosteoporotic functions.

Science.gov (United States)

Landi, Elena; Uggeri, Jacopo; Medri, Valentina; Guizzardi, Stefano

2013-09-01

Porous macro-granules of nanostructured apatite with Ca ions partially cosubstituted with Mg and Sr ions in different ratios (SrMgHAs), were synthesized at 37°C and compared with Mg and/or Sr free apatites (MgHAs and HA). Strontium improved the Mg substitution extent in the apatite and the chemical-physical and thermal stability of the resulting cosubstituted apatite. Porous macro-granules of 400-600 micron with selected composition were tested for the ionic release in synthetic body fluid and the data were related with the results of preliminary cell investigation in vitro. As compared to the corresponding Sr-free granulate, the SrMgHA could be exploited to prolong the beneficial Mg release during the bone regeneration process. In addition the contemporary in situ supply of Sr, an antiosteoporotic and anticarie ion, could influence the quality of new hard tissues. The ionic multirelease created a more favorable environment for human osteoblasts, demonstrated by a proliferative effect for each dose tested in the range 0.1-10 mg/mL. Copyright © 2013 Wiley Periodicals, Inc.

Facilitation of acetylcholine release in rat frontal cortex by indeloxazine hydrochloride: involvement of endogenous serotonin and 5-HT4 receptors.

Science.gov (United States)

Yamaguchi, T; Suzuki, M; Yamamoto, M

1997-12-01

Effects of indeloxazine hydrochloride, an inhibitor of serotonin (5-HT) and norepinephrine (NE) reuptake with a facilitatory effect on 5-HT release, on acetylcholine (ACh) output in frontal cortex of conscious rats were characterized using an in vivo microdialysis technique. Systemic administration of indeloxazine (3 and 10 mg/kg, i.p.) increased ACh and 5-HT output in a dose-dependent manner. Depletion of endogenous monoamines by reserpine and of 5-HT by p-chlorophenylalanine, but not that of catecholamines by alpha-methyl-p-tyrosine, significantly attenuated the facilitatory effect of indeloxazine on ACh release. When applied locally by reverse dialysis, indeloxazine (10 and 30 microM) and the selective 5-HT reuptake inhibitor citalopram (10 microM), but not the NE reuptake inhibitor maprotiline (30 microM), increased cortical ACh output. Indeloxazine (10 mg/kg)-induced increase in ACh release was significantly inhibited by local application of the 5-HT4 receptor antagonists RS23597 (50 microM) and GR113803 (1 microM), while the 5-HT1A antagonist WAY-100135 (100 microM), 5-HT1A/1B/beta-adrenoceptor antagonist (-)propranolol (150 microM), 5-HT2A/2C antagonist ritanserin (10 microM) and 5-HT3 antagonist ondansetron (10 microM) failed to significantly modify this effect. Neither depletion of monoamines nor treatment with serotonergic antagonists significantly changed the basal ACh level, indicating that endogenous monoamines do not tonically activate ACh release. These results suggest that indeloxazine-induced facilitation of ACh release in rat frontal cortex is mediated by endogenous 5-HT and involves at least in part cortical 5-HT4 receptors.

Sol-gel Derived Warfarin - Silica Composites for Controlled Drug Release.

Science.gov (United States)

Dolinina, Ekaterina S; Parfenyuk, Elena V

2017-01-01

Warfarin, commonly used anticoagulant in clinic, has serious shortcomings due to its unsatisfactory pharmacodynamics. One of the efficient ways for the improvement of pharmacological and consumer properties of drugs is the development of optimal drug delivery systems. The aim of this work is to synthesize novel warfarin - silica composites and to study in vitro the drug release kinetics to obtain the composites with controlled release. The composites of warfarin with unmodified (UMS) and mercaptopropyl modified silica (MPMS) were synthesized by sol-gel method. The composite formation was confirmed by FTIR spectra. The concentrations of warfarin released to media with pH 1.6, 6.8 and 7.4 were measured using UV spectroscopy. The drug release profiles from the solid composites were described by a series of kinetic models which includes zero order kinetics, first order kinetics, the modified Korsmeyer-Peppas model and Hixson-Crowell model. The synthesized sol-gel composites have different kinetic behavior in the studied media. In contrast to the warfarin composite with unmodified silica, the drug release from the composite with mercaptopropyl modified silica follows zero order kinetics for 24 h irrespective to the release medium pH due to mixed mechanism (duffusion + degradation and/or disintegration of silica matrix). The obtained results showed that warfarin - silica sol-gel composites have a potential application for the development of novel oral formulation of the drug with controlled delivery. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of bioceramic functional groups on drug binding and release kinetics

Science.gov (United States)

Trujillo, Christopher

Bioceramics have been studied extensively as drug delivery systems (DDS). Those studies have aimed to tailor the drug binding and release kinetics to successfully treat infections and other diseases. This research suggests that the drug binding and release kinetics are predominantly driven by the functional groups available on the surface of a bioceramic. The goal of the present study is to explain the role of silicate and phosphate functional groups in drug binding to and release kinetics from bioceramics. alpha-cristobalite (Cris; SiO2) particles (90-150 microm) were prepared and doped with 0 microg (P-0), 39.1 microg (P-39.1), 78.2 microg (P-78.2), 165.5 microg (P-165.5) or 331 microg (P-331) of P 2O5 per gram Cris, using 85% orthophosphoric (H3PO 4) acid and thermal treatment. The material structure was analyzed using X-ray diffraction (XRD) with Rietveld Refinement and Fourier Transform Infrared (FTIR) spectroscopy with Gaussian fitting. XRD demonstrated an increase from sample P-0 (170.5373 A3) to P-331 (170.6466 A 3) in the unit cell volume as the P2O5 concentration increased in the material confirming phosphate silicate substitution in Cris. Moreover, FTIR showed the characteristic bands of phosphate functional groups of nu4 PO4/O-P-O bending, P-O-P stretching, P-O-P bending, P=O stretching, and P-O-H bending in doped Cris indicating phosphate incorporation in the silicate structure. Furthermore, FTIR showed that the nu4 PO4/O-P-O bending band around 557.6 cm-1 and P=O stretching band around 1343.9 cm-1 increased in area for samples P-39.1 to P-331 from 3.5 to 10.5 and from 10.1 to 22.4, respectively due to phosphate doping. In conjunction with the increase of the nu4 PO4/O-P-O bending band and P=O stretching band, a decrease in area of the O-Si-O bending bands around 488.1 and 629.8 cm-1 was noticed for samples P-39.1 to P-331 from 5 to 2 and from 11.8 to 5.4, respectively. Furthermore, Cris samples (200 mg, n=5 for each sample) were immersed separately in

Microstructure and high temperature stability of age hardenable AA2219 aluminium alloy modified by Sc, Mg and Zr additions

Energy Technology Data Exchange (ETDEWEB)

Naga Raju, P. [Metallurgical and Materials Engineering Department, IIT-Madras, Chennai 600036 (India)], E-mail: puvvala_nagaraju@yahoo.com; Srinivasa Rao, K. [Metallurgical Engineering Department, Andhra University, Visakapatnam 530003 (India); Reddy, G.M. [Defence Metallurgical Research Laboratory, Hyderabad 500258 (India); Kamaraj, M.; Prasad Rao, K. [Metallurgical and Materials Engineering Department, IIT-Madras, Chennai 600036 (India)

2007-08-25

The present work pertains to the improvement of high temperature stability of age hardenable AA2219 aluminium-copper (6.3%) alloy. Addition of scandium, magnesium and zirconium to the base metal AA2219 was adopted to improve this high temperature stability. These additions were systematically varied by preparing alloys of different composition using gas tungsten arc melting. Long time ageing studies and impression creep technique were used to study the high temperature stability of the alloys. These modified compositions of the alloy resulted in fine equiaxed grains, refined eutectics, large number of high temperature stable and finer precipitates. Among all the compositions, 0.8% Sc + 0.45% Mg + 0.2% Zr addition was found to be significant in improving the high temperature stability of AA2219 alloy. This may be attributed to the possible microstructural changes, solute enrichment of the matrix and pinning of the grain boundaries by the finer precipitates.

Hydrogen storage stability of nanoconfined MgH2 upon cycling

DEFF Research Database (Denmark)

Huen, Priscilla; Paskevicius, Mark; Richter, Bo

2017-01-01

It is of utmost importance to optimise and stabilise hydrogen storage capacity during multiple cycles of hydrogen release and uptake to realise a hydrogen-based energy system. Here, the direct solvent-based synthesis of magnesium hydride, MgH2, from dibutyl magnesium, MgBu2, in four different...... issues are highlighted relating to the presence of unwanted gaseous by-products, Mg/MgH2 containment within the scaffold, and the purity of the carbon aerogel scaffold. The results presented provide a research path for future researchers to improve the nanoconfinement process for hydrogen storage...... carbon aerogels with different porosities, i.e., pore sizes, 15 hydrogenations, are conducted for each scaffold...

Controlled release of diuron from an alginate-bentonite formulation: water release kinetics and soil mobility study.

Science.gov (United States)

Fernández-Pérez, M; Villafranca-Sánchez, M; González-Pradas, E; Flores-Céspedes, F

1999-02-01

The herbicide diuron was incorporated in alginate-based granules to obtain controlled release (CR) properties. The standard formulation (alginate-herbicide-water) was modified by the addition of different sorbents. The effect on diuron release rate caused by incorporation of natural and acid-treated bentonites in alginate formulation was studied by immersion of the granules in water under static conditions. The release of diuron was diffusion-controlled. The time taken for 50% release of active ingredient to be released into water, T(50), was calculated for the comparison of formulations. The addition of bentonite to the alginate-based formulation produced the higher T(50) values, indicating slower release of the diuron. The mobility of technical and formulated diuron was compared by using soil columns. The use of alginate-based CR formulations containing bentonite produced a less vertical distribution of the active ingredient as compared to the technical product and commercial formulation. Sorption capacities of the various soil constituents for diuron were also determined using batch experiments.

Removal of Pb(II) from aqueous solution using modified and unmodified kaolinite clay

International Nuclear Information System (INIS)

Jiang Mingqin; Wang Qingping; Jin Xiaoying; Chen Zuliang

2009-01-01

Modified kaolinite clay with 25% (w/w) aluminium sulphate and unmodified kaolin were investigated as adsorbents to remove Pb(II) from aqueous solution. The results show that amount of Pb(II) adsorbed onto modified kaolin (20 mg/g) was more than 4.5-fold than that adsorbed onto unmodified kaolin (4.2 mg/g) under the optimized condition. In addition, the linear Langmuir and Freundlich models were used to describe equilibrium isotherm. It is observed that the data from both adsorbents fitted well to the Langmuir isotherm. The kinetic adsorption of modified and unmodified kaolinite clay fitted well to the pseudo-second-order model. Furthermore, both modified and unmodified kaolinite clay were characterized by X-ray diffraction, Fourier transform infrared (FT-IR) and scanning electron microscope (SEM). Finally, both modified and unmodified kaolinite clay were used to remove metal ions from real wastewater, and results show that higher amount of Pb(II) (the concentration reduced from 178 to 27.5 mg/L) and other metal ions were removed by modified kaolinite clay compared with using unmodified adsorbent (the concentration reduced from 178 to 168 mg/L).

Reduced capacity of cardiac efferent sympathetic neurons to release noradrenaline and modify cardiac function in tachycardia-induced canine heart failure.

Science.gov (United States)

Cardinal, R; Nadeau, R; Laurent, C; Boudreau, G; Armour, J A

1996-09-01

To investigate the capacity of efferent sympathetic neurons to modulate the failing heart, stellate ganglion stimulation was performed in dogs with biventricular heart failure induced by rapid ventricular pacing (240 beats/min) for 4-6 weeks. Less noradrenaline was released from cardiac myoneural junctions into coronary sinus blood in response to left stellate ganglion stimulation in anesthetized failing heart preparations (582 pg/mL, lower and upper 95% confidence intervals of 288 and 1174 pg/mL, n = 19) compared with healthy heart preparations (6391 pg/mL, 95% confidence intervals of 4180 and 9770 pg/mL, n = 14; p < 0.001). There was substantial adrenaline extraction by failing hearts (49 +/- 6%), although it was slightly lower than in healthy heart preparations (65 +/- 9%, p = 0.055). In contrast with healthy heart preparations, no net release of adrenaline occurred during stellate ganglion stimulation in any of the failing heart preparations, and ventricular tissue levels of adrenaline fell below the sensitivity limit of the HPLC technique. In failing heart preparations, maximal electrical stimulation of right or left stellate ganglia resulted in minimal augmentation of left ventricular intramyocardial (17%) and chamber (12%) systolic pressures. These indices were augmented by 145 and 97%, respectively, following exogenous noradrenaline administration. Thus, the cardiac efferent sympathetic neurons' reduced capacity to release noradrenaline and modify cardiac function can contribute to reduction of sympathetic support to the failing heart.

Orlistat accelerates gastric emptying and attenuates GIP release in healthy subjects

DEFF Research Database (Denmark)

Enç, Feruze Yilmaz; Ones, Tunç; Akin, H Levent

2008-01-01

Orlistat, an inhibitor of digestive lipases, is widely used for the treatment of obesity. Previous reports on the effect of orally ingested orlistat together with a meal on gastric emptying and secretion of gut peptides that modulate postprandial responses are controversial. We investigated...... the effect of ingested orlistat on gastric emptying and plasma responses of gut peptides in response to a solid mixed meal with a moderate energy load. In healthy subjects, gastric emptying was determined using scintigraphy and studies were performed without and with 120 mg of orlistat in pellet form......, implying that inhibition of fat absorption modifies determinants of gastric emptying of a meal. Orlistat administered similar to its use in obesity treatment accelerates gastric emptying of a solid mixed meal with a moderate energy load and profoundly attenuates release of GIP without appreciably altering...

Paracetamol (acetaminophen) attenuates in vitro mast cell and peripheral blood mononucleocyte cell histamine release induced by N-acetylcysteine.

Science.gov (United States)

Coulson, James; Thompson, John Paul

2010-02-01

The treatment of acute paracetamol (acetaminophen) poisoning with N-acetylcysteine (NAC) is frequently complicated by an anaphylactoid reaction to the antidote. The mechanism that underlies this reaction is unclear. We used the human mast cell line 1 (HMC-1) and human peripheral blood mononucleocytes (PBMCs) to investigate the effects of NAC and paracetamol on histamine secretion in vitro. HMC-1 and human PBMCs were incubated in the presence of increasing concentrations of NAC +/- paracetamol. Cell viability was determined by the Trypan Blue Assay, and histamine secretion was measured by ELISA. NAC was toxic to HMC-1 cells at 100 mg/mL and to PBMCs at 67 mg/mL. NAC increased HMC-1 and PBMC histamine secretion at concentrations of NAC from 20 to 50 mg/mL and 2.5 to 100 mg/mL, respectively. NAC-induced histamine secretion by both cell types was reduced by co-incubation with 2.5 mg/mL of paracetamol. Paracetamol (acetaminophen) is capable of modifying histamine secretion in vitro. This may explain the clinical observation of a lower incidence of adverse reactions to NAC in vivo when higher concentrations of paracetamol are present than when paracetamol concentrations are low. Paracetamol (acetaminophen) attenuates in vitro mast cell and PBMC cell histamine release induced by NAC.

Optimization of caseinate-coated simvastatin-zein nanoparticles: improved bioavailability and modified release characteristics

Directory of Open Access Journals (Sweden)

Ahmed OA

2015-01-01

Full Text Available Osama AA Ahmed,1,2 Khaled M Hosny,1,3 Majid M Al-Sawahli,1,4 Usama A Fahmy11Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, King Abdulaziz University, Jeddah, Saudi Arabia; 2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Minia University, Minia, Egypt; 3Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Beni Suef University, Beni Suef, Egypt; 4Holding Company for Biological Products & Vaccines (VACSERA, Cairo, EgyptAbstract: The current study focuses on utilization of the natural biocompatible polymer zein to formulate simvastatin (SMV nanoparticles coated with caseinate, to improve solubility and hence bioavailability, and in addition, to modify SMV-release characteristics. This formulation can be utilized for oral or possible depot parenteral applications. Fifteen formulations were prepared by liquid–liquid phase separation method, according to the Box–Behnken design, to optimize formulation variables. Sodium caseinate was used as an electrosteric stabilizer. The factors studied were: percentage of SMV in the SMV-zein mixture (X1, ethanol concentration (X2, and caseinate concentration (X3. The selected dependent variables were mean particle size (Y1, SMV encapsulation efficiency (Y2, and cumulative percentage of drug permeated after 1 hour (Y3. The diffusion of SMV from the prepared nanoparticles specified by the design was carried out using an automated Franz diffusion cell apparatus. The optimized SMV-zein formula was investigated for in vivo pharmacokinetic parameters compared with an oral SMV suspension. The optimized nanosized SMV-zein formula showed a 131 nm mean particle size and 89% encapsulation efficiency. In vitro permeation studies displayed delayed permeation characteristics, with about 42% and 85% of SMV cumulative amount released after 12 and 48 hours, respectively. Bioavailability estimation in rats revealed an augmentation in SMV bioavailability

Development and characterization of ferrihydrite-modified diatomite as a phosphorus adsorbent.

Science.gov (United States)

Xiong, Wenhui; Peng, Jian

2008-12-01

A novel phosphorus adsorbent, ferrihydrite-modified diatomite was developed and characterized in this study. The ferrihydrite-modified diatomite was made through surface modification treatments including NaOH treatment and ferrihydrite deposition on raw diatomite. In the NaOH treatment, surface SiO(2) of diatomite was partially dissolved in the NaOH solution. The dissolved Si contributed to form the stable 2-line ferrihydrite which deposited into the macropores and mesopores of diatomite. Blocking macropores and larger mesopores of diatomite with 0.24g Fe/g of 2-line ferrihydrite resulted in a specific surface area of 211.1m(2)/g for the ferrihydrite-modified diatomite, which is 8.5-fold increase than the raw diatomite (24.77m(2)/g). The surface modification also increased the point of zero charge (pH(PZC)) values to 10 for the ferrihydrite-modified diatomite from 5.8 for the raw diatomite. Because of the increased surface area and surface charge, the maximum adsorption capacity of ferrihydrite-modified diatomite at pH 4 and pH 8.5 was increased from 10.2mgP/g and 1.7mgP/g of raw diatomite to 37.3mgP/g and 13.6mgP/g, respectively.

Effect of Mg content on microstructure and corrosion behavior of hot dipped Zn–Al–Mg coatings

Energy Technology Data Exchange (ETDEWEB)

Yao, Caizhen; Lv, Haibing [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Zhu, Tianping [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand); Zheng, Wanguo [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Yuan, Xiaodong, E-mail: xdyuan@caep.cn [Research Centre of Laser Fusion, CAEP, P.O.Box 919-988-5, Mianyang, Sichuan 621900 (China); Gao, Wei, E-mail: w.gao@auckland.ac.nz [Department of Chemical and Materials Engineering, The University of Auckland, PB 92019, Auckland 1142 (New Zealand)

2016-06-15

In this article, Zn–Al–Mg coatings were prepared by hot dipping method. The surface morphology, cross–section microstructure, microhardness, composition, corrosion behaviour of ZAM coatings were investigated by using X–ray diffraction (XRD), Optical microscope, Environmental scanning electron microscopy equipped with EDS (FESEM–EDS), Microhardness tester and Electrochemical analysis respectively. Corrosion test was also performed in a standard salt fog spray chamber. Microstructure studies indicates that Zn grain size was refined and eutectic areas at Zn grain boundary areas increased with increasing Mg content. ZA5M1.5 and ZA5M2 coatings have two distinct layers. Mg tends to exist in the outer layer while Al is in the inner layer. The inner layer is composed of Al{sub 5}Fe{sub 2}Zn{sub 0.4} intermetallic, which may to contribute to the microhardness. The outer layer is Zn grains surrounded by Zn–Mg etutectics, which may improve the corrosion resistance. The microhardness is more than 700 HV{sub 50g} for Al-rich layer and around 151 HV{sub 25g} for Mg-rich layer. The improved corrosion resistance of Zn–5%Al-1.5%Mg coating comes from the corrosion product of flocculent type simonkolleite, which prolongs the micro-path and impedes the movement of O{sub 2} and H{sub 2}O, ultimately retards the overall corrosion process. - Highlights: • Two-layer structured Zn–Al–Mg coatings were prepared by hot dipping method. • Mg exists in the outer layer while Al exists in the inner layer of Zn–Al–Mg coating. • Zn–Al–Mg coating has better protective ability than Zn and Zn–Al coatings. • The Mg-modified simonkolleite is the reason of the enhanced corrosion resistance.

alpha-difluoromethylornithine modifies gonadotropin-releasing hormone release and follicle-stimulating hormone secretion in the immature female rat.

Science.gov (United States)

Thyssen, S M; Becú-Villalobos, D; Lacau-Mengido, I M; Libertun, C

1997-06-01

Polyamines play an essential role in tissue growth and differentiation, in body weight increment, in brain organization, and in the molecular mechanisms of hormonal action, intracellular signaling, and cell-to-cell communication. In a previous study, inhibition of their synthesis by alpha-difluoromethylornithine (DFMO), a specific and irreversible inhibitor of ornithine decarboxylase, during development in female rats, was followed by prolonged high follicle-stimulating hormone (FSH) serum level and a delayed puberty onset. Those changes were relatively independent of body mass and did not impair posterior fertility. The present work studies the mechanisms and site of action of polyamine participation in FSH secretion during development. DFMO was injected in female rats between Days 1 and 9 on alternate days. At 10 days of age, hypothalami from control and DFMO rats were perifused in vitro, and basal and potassium-induced gonadotropin-releasing hormone (GnRH) release were measured. The response to membrane depolarization was altered in DFMO hypothalami. Increased GnRH release in response to a low K+ concentration was evidenced. Adenohypophyses of the same treated prepubertal rats were perifused in vitro and the response to GnRH pulses was checked. In DFMO-treated rats, higher FSH release was observed, with no changes in LH or PRL secretion. Finally, pituitary GnRH receptor number in adenohypophyseal membranes from treated and control groups was quantified. A significant reduction in specific binding was evident in hypophyses from DFMO-treated rats when compared with binding in the control group. In summary, DFMO treatment in a critical developmental period in the female rat impacts the immature GnRH neuronal network and immature gonadotropes. A delay in maturation is evidenced by a higher sensitivity to secretagogs in both pituitary glands and hypothalamic explants. These events could explain the prolonged high FSH serum levels and delayed puberty onset seen in

Centrifugally cast Zn-27Al-xMg-ySi alloys and their in situ (Mg2Si + Si)/ZA27 composites

International Nuclear Information System (INIS)

Wang Qudong; Chen Yongjun; Chen Wenzhou; Wei Yinhong; Zhai Chunquan; Ding Wenjiang

2005-01-01

Effects of composition, mold temperature, rotating rate and modification on microstructure of centrifugally cast Zn-27Al-xMg-ySi alloys have been investigated. In situ composites of Zn-27Al-6.3Mg-3.7Si and Zn-27Al-9.8Mg-5.2Si alloys were fabricated by centrifugal casting using heated permanent mold. These composites consist of three layers: inner layer segregates lots of blocky primary Mg 2 Si and a litter blocky primary Si, middle layer contains without primary Mg 2 Si and primary Si, outer layer contains primary Mg 2 Si and primary Si. The position, quantity and distribution of primary Mg 2 Si and primary Si in the composites are determined jointly by alloy composition, solidification velocity under the effect of centrifugal force and their floating velocity inward. Na salt modifier can refine grain and primary Mg 2 Si and make primary Mg 2 Si distribute more evenly and make primary Si nodular. For centrifugally cast Zn-27Al-3.2Mg-1.8Si alloy, the microstructures of inner layer, middle layer and outer layer are almost similar, single layer materials without primary Mg 2 Si and primary Si are obtained, and their grain sizes increased with the mold temperature increasing

Biomimetic synthesis of modified calcium phosphate fine powders and their in vitro studies

Energy Technology Data Exchange (ETDEWEB)

Gergulova, R., E-mail: rumigg@yahoo.com; Tepavitcharova, S., E-mail: rumigg@yahoo.com; Rabadjieva, D., E-mail: rumigg@yahoo.com; Sezanova, K., E-mail: rumigg@yahoo.com; Ilieva, R., E-mail: rumigg@yahoo.com [Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia (Bulgaria); Alexandrova, R.; Andonova-Lilova, B. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, BAS, Acad. G. Bonchev Str., Bl. 25, Sofia (Bulgaria)

2013-12-16

Biomimetic approach and subsequent high-temperature treatment were used to synthesize ion modified calcium phosphate fine powders. Thus, using Simulated Body Fluid (SBF) as an ion modifier, a bi-phase mixture of ion modified β-tricalcium phosphate and hydroxyapatite (β-TCP + HA) was prepared. The use of SBF electrolyte solution enriched with Mg{sup 2+} or Zn{sup 2+} yielded monophase β-tricalcium phosphate additionally modified with Mg{sup 2+} or Zn{sup 2+} (Mg-β-TCP or Zn-β-TCP). The in vitro behavior of the prepared powders on cell viability and proliferation of murine BALB/c 3T3 fibroblasts and of human Lep 3 cells was studied by MTT test assays and Mosmann method after 72 h incubation. The relative cell viability was calculated.

Characteristics of CO2 release from forest soil in the mountains near Beijing.

Science.gov (United States)

Sun, Xiang Yang; Gao, Cheng Da; Zhang, Lin; Li, Su Yan; Qiao, Yong

2011-04-01

CO2 release from forest soil is a key driver of carbon cycling between the soil and atmosphere ecosystem. The rate of CO2 released from soil was measured in three forest stands (in the mountainous region near Beijing, China) by the alkaline absorption method from 2004 to 2006. The rate of CO2 released did not differ among the three stands. The CO2 release rate ranged from - 341 to 1,193 mg m(-2) h(-1), and the mean value over all three forests and sampling times was 286 mg m(-2) h(-1). CO2 release was positively correlated with soil water content and the soil temperature. Diurnally, CO2 release was higher in the day than at night. Seasonally, CO2 release was highest in early autumn and lowest in winter; in winter, negative values of CO2 release suggested that CO2 was absorbed by soil.

Analytical Method Development and Validation for the Quantification of Acetone and Isopropyl Alcohol in the Tartaric Acid Base Pellets of Dipyridamole Modified Release Capsules by Using Headspace Gas Chromatographic Technique

Directory of Open Access Journals (Sweden)

Sriram Valavala

2018-01-01

Full Text Available A simple, sensitive, accurate, robust headspace gas chromatographic method was developed for the quantitative determination of acetone and isopropyl alcohol in tartaric acid-based pellets of dipyridamole modified release capsules. The residual solvents acetone and isopropyl alcohol were used in the manufacturing process of the tartaric acid-based pellets of dipyridamole modified release capsules by considering the solubility of the dipyridamole and excipients in the different manufacturing stages. The method was developed and optimized by using fused silica DB-624 (30 m × 0.32 mm × 1.8 µm column with the flame ionization detector. The method validation was carried out with regard to the guidelines for validation of analytical procedures Q2 demanded by the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH. All the validation characteristics were meeting the acceptance criteria. Hence, the developed and validated method can be applied for the intended routine analysis.

Formulation of a modified release metformin. HCl matrix tablet: influence of some hydrophilic polymers on release rate and in-vitro evaluation

Directory of Open Access Journals (Sweden)

John Rojas

2011-09-01

Full Text Available Metformin hydrochloride is an antidiabetic agent which improves glucose tolerance in patients with type 2 diabetes and reduces basal plasma levels of glucose. In this study, a simplex centroid experimental design with 69 runs was used to select the best combination of some hydrophilic polymers that rendered a 24 h in-vitro release profile of metformin.HCl. The Korsmeyer-Peppas model was used to model the dissolution profiles since it presented the best fit to the experimental data. Further, a cubic model predicted the best formulation of metformin.HCl containing polyvinyl pyrrolidone, ethyl cellulose, hydroxypropyl methyl cellulose, carrageenan, sodium alginate, and gum arabic at 6.26, 68.7, 6.26, 6.26, 6.26 and 6.26 % levels, respectively. The validation runs confirmed the accuracy of the cubic model with six components for predicting the best set of components which rendered a once-a-day modified release hydrophilic matrix tablet in compliance with the USP specifications.O cloridrato de metformina é um agente antidiabético que melhora a tolerância à glicose em pacientes com diabetes tipo 2 e reduz os níveis plasmáticos basais de glicose. Neste estudo, um projeto experimental do tipo "centróide simplex" com 69 tomadas foi usado para selecionar a melhor combinação de alguns polímeros hidrofílicos que gerou um perfil de liberação da metformina.HCl de 24 horas. O modelo Korsmeyer-Peppas foi usado para modelar os perfis de dissolução, uma vez que apresentou os melhores ajustes aos dados experimentais. Além disso, um modelo cúbico previu a melhor formulação de metformina.HCl sendo aquela contendo polivinilpirrolidona, etilcelulose, hidroxipropilmetil celulose, carragena, alginato de sódio e goma arábica nos níveis 6.26, 68.7, 6.26, 6.26, 6.26 e 6.26 %, respectivamente. As corridas de validação confirmaram a precisão do modelo cúbico com os seis componentes para prever o melhor conjunto de componentes que originou uma

Sustained Release Drug Delivery Applications of Polyurethanes

Directory of Open Access Journals (Sweden)

Michael B. Lowinger

2018-05-01

Full Text Available Since their introduction over 50 years ago, polyurethanes have been applied to nearly every industry. This review describes applications of polyurethanes to the development of modified release drug delivery. Although drug delivery research leveraging polyurethanes has been ongoing for decades, there has been renewed and substantial interest in the field in recent years. The chemistry of polyurethanes and the mechanisms of drug release from sustained release dosage forms are briefly reviewed. Studies to assess the impact of intrinsic drug properties on release from polyurethane-based formulations are considered. The impact of hydrophilic water swelling polyurethanes on drug diffusivity and release rate is discussed. The role of pore formers in modulating drug release rate is examined. Finally, the value of assessing mechanical properties of the dosage form and approaches taken in the literature are described.

Optoelectronic properties of XIn2S4 (X = Cd, Mg) thiospinels through highly accurate all-electron FP-LAPW method coupled with modified approximations

International Nuclear Information System (INIS)

Yousaf, Masood; Dalhatu, S.A.; Murtaza, G.; Khenata, R.; Sajjad, M.; Musa, A.; Rahnamaye Aliabad, H.A.; Saeed, M.A.

2015-01-01

Highlights: • Highly accurate all-electron FP-LAPW+lo method is used. • New physical parameters are reported, important for the fabrication of optoelectronic devices. • A comparative study that involves FP-LAPW+lo method and modified approximations. • Computed band gap values have good agreement with the experimental values. • Optoelectronic results of fundamental importance can be utilized for the fabrication of devices. - Abstract: We report the structural, electronic and optical properties of the thiospinels XIn 2 S 4 (X = Cd, Mg), using highly accurate all-electron full potential linearized augmented plane wave plus local orbital method. In order to calculate the exchange and correlation energies, the method is coupled with modified techniques such as GGA+U and mBJ-GGA, which yield improved results as compared to the previous studies. GGA+SOC approximation is also used for the first time on these compounds to examine the spin orbit coupling effect on the band structure. From the analysis of the structural parameters, robust character is predicted for both materials. Energy band structures profiles are fairly the same for GGA, GGA+SOC, GGA+U and mBJ-GGA, confirming the indirect and direct band gap nature of CdIn 2 S 4 and MgIn 2 S 4 materials, respectively. We report the trend of band gap results as: (mBJ-GGA) > (GGA+U) > (GGA) > (GGA+SOC). Localized regions appearing in the valence bands for CdIn 2 S 4 tend to split up nearly by ≈1 eV in the case of GGA+SOC. Many new physical parameters are reported that can be important for the fabrication of optoelectronic devices. Optical spectra namely, dielectric function (DF), refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and electron loss function are discussed. Optical’s absorption edge is noted to be 1.401 and 1.782 for CdIn 2 S 4 and MgIn 2 S 4 , respectively. The prominent peaks in the electron energy spectrum

Development and evaluation of targeting ligands surface modified paclitaxel nanocrystals

Energy Technology Data Exchange (ETDEWEB)

Sohn, Jeong Sun [Division of Undeclared Majors, Chosun University, Gwangju 501-759 (Korea, Republic of); Yoon, Doo-Soo; Sohn, Jun Youn [Department of Bioenvironmental & Chemical Engineering, Chosun College of Science & Technology, Gwangju 501-744 (Korea, Republic of); Park, Jeong-Sook, E-mail: eicosa@cnu.ac.kr [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of); Choi, Jin-Seok, E-mail: c34281@gmail.com [College of Pharmacy and Institute of Drug Research and Development, Chungnam National University, 99 Daehak-ro, Yuseong-gu, Daejeon 34134 (Korea, Republic of)

2017-03-01

To overcome the toxicity of excipient or blank nanoparticles for drug delivery nano-system, the surface modified paclitaxel nanocrystals (PTX-NC) have been developed. PTX-NCs were prepared by nano-precipitation method. The surface of PTX-NCs were modified by grafting with apo-transferrin (Tf) or hyaluronic acid (HA). The physical properties of PTX-NCs were evaluated by field emission scanning electron microscope (FE-SEM), zeta-sizer, zeta-potential, differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectrometry. In vitro drug release study was performed in phosphate buffered saline (PBS) with or without 0.5% (w/v) Tween 80 for 24 h. Cellular uptake was studied at time intervals of 0.5, 1, and 2 h in MCF-7 cells, and cell growth inhibition study was performed for 24 h using MCF-7 cells (cancer cells), and HaCaT cells (normal cells). Three different types of PTX-NCs with a mean size of 236.0 ± 100.6 nm (PTX-NC), 302.0 ± 152.0 nm (Tf-PTX-NC) and 339 ± 180.6 nm (HA-PTX-NC) were successfully prepared. The drug release profiles showed 29.1%/6.9% (PTX (pure)), 40.7%/23.9% (PTX-NC), 50.5%/25.1% (Tf-PTX-NC) and 46.8/24.8% (HA-PTX-NC) in PBS with/without 0.5% (w/v) Tween 80 for 24 h, respectively. As per the results, the drug release of PTX-NCs showed the faster release as compared to that of PTX (pure). Surface modified PTX-NCs exhibited higher values for cell permeability than unmodified PTX-NC in the cellular uptake study. Surface modified PTX-NCs inhibited the cell growth approximately to 60% in MCF-7 cells, however effect of surface modified PTX-NCs on normal cell line was lower than the PTX-NC and PTX (pure). In conclusion, biological macromolecules (Tf or HA) surface modified PTX-NC enhanced the cellular uptake and the cell growth inhibition. - Highlights: • Surface modified PTX-NCs with HA and Tf are successfully prepared by adsorption method. • Enhanced cellular uptake of modified PTX-NCs compared to unmodified PTX-NC • Improved

Solid-Phase Synthesis of Modified Peptides as Putative Inhibitors of Histone Modifying Enzymes

DEFF Research Database (Denmark)

Cohrt, Anders Emil O'Hanlon

to be compatible with all 20 naturally occurring amino acids, and were furthermore feasible on several commonly used polymeric supports. By using dilute SnCl4 for N -Boc deprotection, and NaOH for the release of material from the solid support, N -modified peptides were cleanly obtained in excellent yields...

Antifouling composites with self-adaptive controlled release based on an active compound intercalated into layered double hydroxides

Science.gov (United States)

Yang, Miaosen; Gu, Lianghua; Yang, Bin; Wang, Li; Sun, Zhiyong; Zheng, Jiyong; Zhang, Jinwei; Hou, Jian; Lin, Cunguo

2017-12-01

This paper reports a novel method to prepare the antifouling composites with properties of self-adaptive controlled release (defined as control the release rate autonomously and adaptively according to the change of environmental conditions) by intercalation of sodium paeonolsilate (PAS) into MgAl and ZnAl layered double hydroxide (LDH) with the molar ratio (M2+/M3+) of 2:1 and 3:1, respectively. The powder X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) confirm the intercalation of PAS into the galleries of LDH. The controlled release behavior triggered by temperature for the PAS-LDH composites has been investigated, and the results show that the release rate of all PAS-LDH composites increases as the increase of temperature. However, the MgAl-PAS-LDH composites (Mg2Al-PAS-LDH and Mg3Al-PAS-LDH) exhibit the increased release rate of 0.21 ppm/°C from 15 to 30 °C in 3.5% NaCl solution, more than three times of the ZnAl-PAS-LDH composites (0.06 ppm/°C), owing to the confined microenvironment influenced by metal types in LDH layers. In addition, a possible diffusion-controlled process with surface diffusion, bulk diffusion and heterogeneous flat surface diffusion has been revealed via fitting four kinetic equations. Moreover, to verify the practical application of the PAS-LDH composites, a model coating denoted as Mg2Al-PAS-LDH coating was fabricated. The release result displays that the release rate increases or decreases as temperature altered at 15 and 25 °C alternately, indicating its self-adaptive controlled release behavior with temperature. Moreover, the superior resistance to the settlement of Ulva spores at 15 and 25 °C was observed for the Mg2Al-PAS-LDH coating, as a result of the controllable release of antifoulant. Therefore, this work provides a facile and effective method for the fabrication of antifouling composites with self-adaptive controlled release behavior in response to temperature, which can be used to prolong

Novel self-assembled sandwich nanomedicine for NIR-responsive release of NO

Science.gov (United States)

Fan, Jing; He, Qianjun; Liu, Yi; Ma, Ying; Fu, Xiao; Liu, Yijing; Huang, Peng; He, Nongyue; Chen, Xiaoyuan

2015-01-01

A novel sandwich nanomedicine (GO-BNN6) for near-infrared (NIR) light responsive release of nitric oxide (NO) has been constructed by self-assembling of graphene oxide (GO) nanosheets and a NO donor BNN6 through the π-π stacking interaction. GO-BNN6 nanomedicine has an extraordinarily high drug loading capacity (1.2 mg BNN6 per mg GO), good thermal stability, and high NIR responsiveness. The NO release from GO-BNN6 can be easily triggered and effectively controlled by adjusting the switching, irradiation time and power density of NIR laser. The intracellular NIR-responsive release of NO from GO-BNN6 nanomedicine causes a remarkable anti-cancer effect. PMID:26568270

Catalytically Enhanced Hydrogen Sorption in Mg-MgH2 by Coupling Vanadium-Based Catalyst and Carbon Nanotubes

Directory of Open Access Journals (Sweden)

Atikah Kadri

2015-06-01

Full Text Available Mg (MgH2-based composites, using carbon nanotubes (CNTs and pre-synthesized vanadium-based complex (VCat as the catalysts, were prepared by high-energy ball milling technique. The synergistic effect of coupling CNTs and VCat in MgH2 was observed for an ultra-fast absorption rate of 6.50 wt. % of hydrogen per minute and 6.50 wt. % of hydrogen release in 10 min at 200 °C and 300 °C, respectively. The temperature programmed desorption (TPD results reveal that coupling VCat and CNTs reduces both peak and onset temperatures by more than 60 °C and 114 °C, respectively. In addition, the presence of both VCat and CNTs reduces the enthalpy and entropy of desorption of about 7 kJ/mol H2 and 11 J/mol H2·K, respectively, as compared to those of the commercial MgH2, which ascribe to the decrease of desorption temperature. From the study of the effect of CNTs milling time, it is shown that partially destroyed CNTs (shorter milling time are better to enhance the hydrogen sorption performance.

Stress-induced evolution and the biosafety of genetically modified

Indian Academy of Sciences (India)

This article is focused on the problems of reduction of the risk associated with the deliberate release of genetically modified microorganisms (GMMs) into the environment. Special attention is given to overview the most probable physiological and genetic processes which could be induced in the released GMMs by adverse ...

Single Layer Extended Release Two-in-One Guaifenesin Matrix Tablet: Formulation Method, Optimization, Release Kinetics Evaluation and Its Comparison with Mucinex® Using Box-Behnken Design.

Science.gov (United States)

Morovati, Amirhosein; Ghaffari, Alireza; Erfani Jabarian, Lale; Mehramizi, Ali

2017-01-01

Guaifenesin, a highly water-soluble active (50 mg/mL), classified as a BCS class I drug. Owing to its poor flowability and compressibility, formulating tablets especially high-dose one, may be a challenge. Direct compression may not be feasible. Bilayer tablet technology applied to Mucinex®, endures challenges to deliver a robust formulation. To overcome challenges involved in bilayer-tablet manufacturing and powder compressibility, an optimized single layer tablet prepared by a binary mixture (Two-in-one), mimicking the dual drug release character of Mucinex ® was purposed. A 3-factor, 3-level Box-Behnken design was applied to optimize seven considered dependent variables (Release "%" in 1, 2, 4, 6, 8, 10 and 12 h) regarding different levels of independent one (X 1 : Cetyl alcohol, X 2 : Starch 1500 ® , X 3 : HPMC K100M amounts). Two granule portions were prepared using melt and wet granulations, blended together prior to compression. An optimum formulation was obtained (X 1 : 37.10, X 2 : 2, X 3 : 42.49 mg). Desirability function was 0.616. F2 and f1 between release profiles of Mucinex® and the optimum formulation were 74 and 3, respectively. An n-value of about 0.5 for both optimum and Mucinex® formulations showed diffusion (Fickian) control mechanism. However, HPMC K100M rise in 70 mg accompanied cetyl alcohol rise in 60 mg led to first order kinetic (n = 0.6962). The K values of 1.56 represented an identical burst drug releases. Cetyl alcohol and starch 1500 ® modulated guaifenesin release from HPMC K100M matrices, while due to their binding properties, improved its poor flowability and compressibility, too.

Endurance exercise modulates levodopa induced growth hormone release in patients with Parkinson's disease.

Science.gov (United States)

Müller, Thomas; Welnic, Jacub; Woitalla, Dirk; Muhlack, Siegfried

2007-07-11

Acute levodopa (LD) application and exercise release human growth hormone (GH). An earlier trial showed, that combined stimulus of exercise and LD administration is the best provocative test for GH response in healthy participants. Objective was to show this combined effect of LD application and exercise on GH response and to investigate the impact on LD metabolism in 20 previously treated patients with Parkinson's disease (PD). We measured GH- and LD plasma concentrations following soluble 200 mg LD/50 mg benserazide administration during endurance exercise and rest on two separate consecutive days. GH concentrations significantly increased on both days, but GH release was significantly delayed during rest. LD metabolism was not altered due to exercise in a clinical relevant manner. Exercise induced a significant faster LD stimulated GH release in comparison with the rest condition. We did not find the supposed increase of LD induced GH release by endurance exercise. We assume, that only a limited amount of GH is available for GH release in the anterior pituitary following an acute 200 mg LD administration. GH disposal also depends on growth hormone releasing hormone (GHRH), which is secreted into hypothalamic portal capillaries. During the exercise condition, the resulting higher blood pressure supports blood flow and thus GHRH transport towards the GH producing cells in the pituitary. This might additionally have caused the significant faster GH release during exercise.

Estabilidad de las tabletas de clorodiazepóxido 10 mg

Directory of Open Access Journals (Sweden)

Vivian Tolosa Cubela

1998-04-01

Full Text Available Se estudió la estabilidad de las tabletas de clorodiazepóxido 10 mg que fueron elaboradas con un almidón modificado (GECLYN-ER2 de bajo costo en sustitución de la gelatina, aglutinante tradicional. Se emplearon como métodos analíticos para la cuantificación e identificación de clorodiazepóxido: cromatografía líquida de alta resolución, cromatografía en capa delgada y espectrofotometría. Los resultados obtenidos para las tabletas expuestas en condiciones variables de temperatura, humedad y de vida en estante confirman la factibilidad del empleo de este almidón, modificado para la fabricación de las tabletas de clorodiazepóxido 10 mg.The stability of chlordiazepoxide 10 mg tablets, which were made with low cost modified starch (GECLYN-ER2 to substitute gelatine, the traditional agglutinant, was studied. The following analytical methods were used for the quantification and identification of chlordiazipoxide: high pressure liquid chromatography thin layer chromatography, and spectrophotometry. The results attained for the tablets exposed to different conditions of temperature, humidity and shelf life confirmed the feasibility of this starch that was modified to make chlordiazepoxide 10 mg tablets.

Histamine release inhibitory activity of Piper nigrum leaf.

Science.gov (United States)

Hirata, Noriko; Naruto, Shunsuke; Inaba, Kazunori; Itoh, Kimihisa; Tokunaga, Masashi; Iinuma, Munekazu; Matsuda, Hideaki

2008-10-01

Oral administration of a methanolic extract of Piper nigrum leaf (PN-ext, 50, 200 and 500 mg/kg) showed a potent dose-dependent inhibition of dinitrofluorobenzene (DNFB)-induced cutaneous reaction at 1 h [immediate phase response (IPR)] after and 24 h [late phase response (LPR)] after DNFB challenge in mice which were passively sensitized with anti-dinitrophenyl (DNP) IgE antibody. Ear swelling inhibitory effect of PN-ext (50, 200 and 500 mg/kg, per os (p.o.)) on very late phase response (vLPR) in the model mice was significant but weaker than that on IPR. Oral administration of PN-ext (50, 200 and 500 mg/kg for 7 d) inhibited picryl chloride (PC)-induced ear swelling in PC sensitized mice. PN-ext exhibited in vitro inhibitory effect on compound 48/80-induced histamine release from rat peritoneal mast cells. Two lignans of PN-ext, (-)-cubebin (1) and (-)-3,4-dimethoxy-3,4-desmethylenedioxycubebin (2), were identified as major active principles having histamine release inhibitory activity.

Minimizing lead release levels in secondary smelters slags

International Nuclear Information System (INIS)

Shenkler, E.S.; Graham, S.; Ghosh, R.; Greenhut, V.A.

1991-01-01

Five lead-containing slags and four mattes were analyzed to reveal microstructure, semi-quantitative microchemistry, and phases present. To determine if the slags could be incorporated as a glass so that lead release levels could be stabilized, glass batches were formulated based on slag compositions. Leaching tests showed that all materials that were fritted in a glass batch had lower lead release levels than non-adjusted materials, and all could satisfy EPA test requirements. The mole ratio of glass modifiers to glass formers played an important role in the extent of lead release. Small additions of phosphate to a batch had a significant effect on lowering lead release levels

Carbon nanotube release from polymers into a food simulant

International Nuclear Information System (INIS)

Xia, Yining; Uysal Unalan, Ilke; Rubino, Maria; Auras, Rafael

2017-01-01

The release assessment of multi-walled carbon nanotubes (CNTs) was performed on two types of polymer-CNT nanocomposites: polypropylene (PP) and polyamide 6 (PA6) containing 3 wt% CNT. Nanocomposite films were prepared and then exposed to ethanol as a fatty-food simulant at 40 °C, and the amount of CNT release into ethanol was determined by ultraviolet-visible spectroscopy (UV-Vis) and graphite furnace atomic absorption spectrometry (GFAAS). The CNTs released into ethanol were visualized by transmission electron microscopy (TEM) and verified by Raman spectroscopy. UV-Vis analysis showed a very small amount of CNT release from the nanocomposite films into ethanol over 60 d: maximum CNT concentrations in ethanol were 1.3 mg/L for the PP-CNT film and 1.2 mg/L for the PA6-CNT film. GFAAS results indicated that the amount of CNTs released into ethanol after 12 d was over 20-fold higher than the results obtained by UV-Vis. Overestimation of CNT release by GFAAS suggested aggregation and poor dispersion of CNTs in the solvent. This assumption was verified by TEM images exhibiting the embedded CNTs in the polymer flakes, which could be poorly dispersed in the solvent. In general, CNT release from the nanocomposite films was considered a surface phenomenon, as indicated by detachment of CNT-containing polymer flakes from the film surface. - Highlights: • Release of CNT from polypropylene and polyamide nanocomposites were quantified and validated with TEM and Raman. • Spectroscopy and silane-labeled CNT were used for tracking the release of CNT. • The release behavior of CNT from nanocomposites was mostly generated from the polymer surfaces.

Advanced tertiary treatment of municipal wastewater using raw and modified diatomite.

Science.gov (United States)

Wu, Jinlu; Yang, Y S; Lin, Jinhua

2005-12-09

Advanced technology for more efficient and effective wastewater treatment is always timely needed. The feasibility of using raw and modified diatomite for advanced treatment of secondary sewage effluents (SSE) was investigated in this study. Raw diatomite at a dosing rate of 300 mg/l showed a similar potential as activated carbon for removing most organic pollutants and toxic metals from SSE. Its performance was found poor in removal of arsenic and crop nutrient constituents (e.g. ammoniacal nitrogen and phosphate) and remained unsatisfactory even when the dosing rate increased up to 500 mg/l. Where modified diatomite was in lieu of raw diatomite, the removal efficiency for all target constituents was improved by 20-50%. At the dosing rate of 150 mg/l, modified diatomite enabled the post-treated effluents to satisfy the discharge consents, with the levels of all target constituents below the regulatory limits. Modified diatomite has advantages over raw diatomite in improving removal efficiency and reducing the dosing rate required for satisfactory treatment of SSE. It is concluded that modified diatomite is much more effective and efficient than raw diatomite, as an alternative to activated carbon, for economic treatment of SSE.

Facile fabrication of hydrophobic surfaces on mechanically alloyed-Mg/HA/TiO{sub 2}/MgO bionanocomposites

Energy Technology Data Exchange (ETDEWEB)

Khalajabadi, Shahrouz Zamani [Medical Devices and Technology Group (MEDITEG), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Abdul Kadir, Mohammed Rafiq, E-mail: rafiq@biomedical.utm.my [Medical Devices and Technology Group (MEDITEG), Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Izman, Sudin; Mohd Yusop, Mohd Zamri [Department of Materials, Manufacturing and Industrial Engineering, Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia)

2015-01-01

Highlights: • Mg/HA/TiO{sub 2}-based nanocomposite was produced using mechanical alloying. • The hydrophobic surface coverage was fabricated on the mechanical alloyed samples by annealing. • The morphological characteristics, phase evolution and wettability of nanocomposites and the hydrophobic surface coverage were investigated. • The activation energies and reaction kinetic of the powder mixture of nanocomposites were calculated. - Abstract: The effect of mechanical alloying and post-annealing on the phase evolution, microstructure, wettability and thermal stability of Mg–HA–TiO{sub 2}–MgO composites was investigated in this study. Phase evolution and microstructure analysis were performed using X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy and atomic force microscopy, as well as the wettability determined by contact angle measurements with SBF. The 16-h mechanical alloying resulted in the formation of MgTiO{sub 3}, CaTiO{sub 3}, Mg{sub 3}(PO{sub 4}){sub 2} and Mg(OH){sub 2} phases and a decrease in wettability of the nanocomposites. A hydrophobic film with hierarchical structures comprising nanoflakes of MgTiO{sub 3}, nano-cuboids of CaTiO{sub 3}, microspheres of Mg{sub 3}(PO{sub 4}){sub 2} and Mg(OH){sub 2} was successfully constructed on the surface of the Mg-based nanocomposites substrates as a result of the post-annealing process. After 1-h annealing at 630 °C, the synthesized hydrophobic surface on the nanocomposite substrates decreased the wettability, as the 8-h-mechanically alloyed samples exhibited a contact angle close to 93°. The formation activation energies and reaction kinetics of the powder mixture were investigated using differential thermal analysis and thermal gravimetric analysis. The released heat, weight loss percentage and reaction kinetics increased, while the formation activation energies of the exothermic reactions decreased following an increase in the milling time.

A modified SILCS contraceptive diaphragm for long-term controlled release of the HIV microbicide dapivirine.

Science.gov (United States)

Major, Ian; Boyd, Peter; Kilbourne-Brook, Maggie; Saxon, Gene; Cohen, Jessica; Malcolm, R Karl

2013-07-01

There is considerable interest in developing new multipurpose prevention technologies to address women's reproductive health needs. This study describes an innovative barrier contraceptive device--based on the SILCS diaphragm--that also provides long-term controlled release of the lead candidate anti-HIV microbicide dapivirine. Diaphragm devices comprising various dapivirine-loaded polymer spring cores overmolded with a nonmedicated silicone elastomer sheath were fabricated by injection molding processes. In vitro release testing, thermal analysis and mechanical characterization were performed on the devices. A diaphragm device containing a polyoxymethylene spring core loaded with 10% w/w dapivirine provided continuous and controlled release of dapivirine over a 6-month period, with a mean in vitro daily release rate of 174 mcg/day. The mechanical properties of the new diaphragm were closely matched to the SILCS diaphragm. The study demonstrates proof of concept for a dapivirine-releasing diaphragm with daily release quantities potentially capable of preventing HIV transmission. In discontinuous clinical use, release of dapivirine may be readily extended over 1 or more years. Copyright © 2013 Elsevier Inc. All rights reserved.

Mg/O2 Battery Based on the Magnesium-Aluminum Chloride Complex (MACC) Electrolyte

DEFF Research Database (Denmark)

Vardar, Galin; Smith, Jeffrey G.; Thomson, Travis

2016-01-01

Mg/O2 cells employing a MgCl2/AlCl3/DME (MACC/DME) electrolyte are cycled and compared to cells with modified Grignard electrolytes, showing that performance of magnesium/oxygen batteries depends strongly on electrolyte composition. Discharge capacity is far greater for MACC/DME-based cells, whil...

Effect of amine functionalization of spherical MCM-41 and SBA-15 on controlled drug release

International Nuclear Information System (INIS)

Szegedi, A.; Popova, M.; Goshev, I.; Mihaly, J.

2011-01-01

MCM-41 and SBA-15 silica materials with spherical morphology and different particle sizes were synthesized and modified by post-synthesis method with 3-aminopropyltriethoxysilane (APTES). A comparative study of the adsorption and release of a model drug, ibuprofen, were carried out. The modified and drug loaded mesoporous materials were characterized by XRD, TEM, N 2 physisorption, thermal analysis, elemental analysis and FT-IR spectroscopy. Surface modification with amino groups resulted in high degree of ibuprofen loading and slow rate of release for MCM-41, whereas it was the opposite for SBA-15. The adsorbed drug content and the delivery rate can be predetermined by the choice of mesoporous material with the appropriate structural characteristics and surface functionality. -- Graphical Abstract: Ibuprofen delivery from the parent and amino-modified spherical MCM-41 materials with 100 nm (small) and 500 nm (large) particle sizes. Display Omitted Highlights: → Spherical type MCM-41 and SBA-15 with different particle sizes were modified by APTES. → Adsorption and release rate of ibuprofen were compared. → High degree of ibuprofen loading, slow release rate for MCM-41, the opposite for SBA-15. → MCM-41 with 100 nm particles was more stable and showed slower release rate

Development and Characterisation of Aluminium Matrix Nanocomposites AlSi10Mg/MgAl2O4 by Laser Powder Bed Fusion

Directory of Open Access Journals (Sweden)

Giulio Marchese

2018-03-01

Full Text Available Recently, additive manufacturing techniques have been gaining attention for the fabrication of parts from aluminium alloys to composites. In this work, the processing of an AlSi10Mg based composite reinforced with 0.5% in weight of MgAl2O4 nanoparticles through laser powder bed fusion (LPBF process is presented. After an initial investigation about the effect of process parameters on the densification levels, the LPBF materials were analysed in terms of microstructure, thermo-mechanical and mechanical properties. The presence of MgAl2O4 nanoparticles involves an increment of the volumetric energy density delivered to the materials, in order to fabricate samples with high densification levels similar to the AlSi10Mg samples. However, the application of different building parameters results in modifying the size of the cellular structures influencing the mechanical properties and therefore, limiting the strengthening effect of the reinforcement.

Carbon nanotube release from polymers into a food simulant.

Science.gov (United States)

Xia, Yining; Uysal Unalan, Ilke; Rubino, Maria; Auras, Rafael

2017-10-01

The release assessment of multi-walled carbon nanotubes (CNTs) was performed on two types of polymer-CNT nanocomposites: polypropylene (PP) and polyamide 6 (PA6) containing 3 wt% CNT. Nanocomposite films were prepared and then exposed to ethanol as a fatty-food simulant at 40 °C, and the amount of CNT release into ethanol was determined by ultraviolet-visible spectroscopy (UV-Vis) and graphite furnace atomic absorption spectrometry (GFAAS). The CNTs released into ethanol were visualized by transmission electron microscopy (TEM) and verified by Raman spectroscopy. UV-Vis analysis showed a very small amount of CNT release from the nanocomposite films into ethanol over 60 d: maximum CNT concentrations in ethanol were 1.3 mg/L for the PP-CNT film and 1.2 mg/L for the PA6-CNT film. GFAAS results indicated that the amount of CNTs released into ethanol after 12 d was over 20-fold higher than the results obtained by UV-Vis. Overestimation of CNT release by GFAAS suggested aggregation and poor dispersion of CNTs in the solvent. This assumption was verified by TEM images exhibiting the embedded CNTs in the polymer flakes, which could be poorly dispersed in the solvent. In general, CNT release from the nanocomposite films was considered a surface phenomenon, as indicated by detachment of CNT-containing polymer flakes from the film surface. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chemically modified Moringa oleifera seed husks as low cost adsorbent for removal of copper from aqueous solution

Science.gov (United States)

Ghafar, Faridah; Mohtar, Aminullah; Sapawe, Norzahir; Hadi, Norulakmal Nor; Salleh, Marmy Roshaidah Mohd

2017-12-01

Moringa oleifera husks (MOH) are an agricultural byproduct that may have potential as adsorbent for removal of heavy metal ions in wastewater such as copper (Cu2+). The release of Cu2+ to the environment by the mining and electroplating industries cause a major problem because it is toxic and can cause liver and kidney problems. Hence, it is important to remove copper before the wastewater can be discharged to the environment. In order to increase the adsorption capacity, the MOH was chemically modified using citric acid. The raw and modified MOH were analyzed using Fourier Transform Infra-Red (FTIR) for identification of functional groups present at the adsorbent surface. The adsorption study was carried out using the batch technique in water bath shaker investigating different parameters; adsorbent dosage (30 - 70 g/L), initial concentration of copper (30 - 150 mg/L), contact time (2 - 90 min), temperature (27 - 60 °C) at constant agitation of 100 rpm. The concentrations of copper in aqueous solution before and after the adsorption process was analyzed using Atomic Absorption Spectrum (AAS). The highest percentage removal of copper was found at 10g/L of adsorbent dosage with 30 mg/L of initial concentration and temperature 30 °C. It was also observed that the adsorption of copper by MOH was approaching to equilibrium at 60 min of reaction time. From the FTIR analysis, it was found that the MOH contains hydroxyl, carboxyl and amine groups. The high adsorption capacity of modified MOH to remove copper from aqueous solution makes it preferable and attractive alternative to commercial adsorbent.

The alginate layer for improving doxorubicin release and radiolabeling stability of chitosan hydrogels

Energy Technology Data Exchange (ETDEWEB)

Kwon, Jeong Il; Lee, Chang Moon; Jeong, Hwan Seok; Hwang, Hyo Sook; Lim, Seok Tae; Sohn, Myung Hee; Jeong, Hwan Jeong [Dept. of Nuclear Medicine and Therapeutic Medicine Research Center, Cyclotron Research Center, Institute for Medical Science, Biomedical Research Institute, Chonbuk National University Medical School, Jeonju (Korea, Republic of); Lee, Chang Moon [Dept. of Biomedical Engineering, Chonnam National University, Yeosu (Korea, Republic of)

2015-12-15

Chitosan hydrogels (CSH) formed through ionic interaction with an anionic molecule are suitable as a drug carrier and a tissue engineering scaffold. However, the initial burst release of drugs from the CSH due to rapid swelling after immersing in a biofluid limits their wide application as a drug delivery carrier. In this study, alginate layering on the surface of the doxorubicin (Dox)-loaded and I-131-labeled CSH (DI-CSH) was performed. The effect of the alginate layering on drug release behavior and radiolabeling stability was investigated. Chitosan was chemically modified using a chelator for I-131 labeling. After labeling of I-131 and mixing of Dox, the chitosan solution was dropped into tripolyphosphate (TPP) solution using an electrospinning system to prepare spherical microhydrogels. The DI-CSH were immersed into alginate solution for 30 min to form the crosslinking layer on their surface. The formation of alginate layer on the DI-CSH was confirmed by Fourier transform infrared spectroscopy (FT-IR) and zeta potential analysis. In order to investigate the effect of alginate layer, studies of in vitro Dox release from the hydrogels were performed in phosphate buffered in saline (PBS, pH 7.4) at 37 °C for 12 days. The radiolabeling stability of the hydrogels was evaluated using ITLC under different experimental condition (human serum, normal saline, and PBS) at 37 °C for 12 days. Formatting the alginate-crosslinked layer on the CSH surface did not change the spherical morphology and the mean diameter (150 ± 10 μm). FT-IR spectra and zeta potential values indicate that alginate layer was formed successfully on the surface of the DI-CSH. In in vitro Dox release studies, the total percentage of the released Dox from the DI-CSH for 12 days were 60.9 ± 0.8, 67.3 ± 1.4, and 71.8 ± 2.5 % for 0.25, 0.50, and 1.00 mg Dox used to load into the hydrogels, respectively. On the other hand, after formatting alginate layer, the percentage of the

Removal of ammonium from aqueous solutions using alkali-modified biochars

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Zhigang Liu

2016-10-01

Full Text Available Biochars converted from agricultural residuals can effectively remove ammonium from water. This work further improved the sorption ability of biochars to aqueous ammonium through alkali modification. Three modified biochars were prepared from agricultural residuals pre-treated with NaOH solution through low-temperature (300 °C slow pyrolysis. The modified biochars effectively removed ammonium ions from water under various conditions with relatively fast adsorption kinetics (reached equilibrium within 10 h and extremely high adsorption capacity (>200 mg/g. The Langmuir maximum capacity of the three modified biochars were between 313.9 and 518.9 mg/g, higher than many other ammonium adsorbents. Although the sorption of ammonium onto the modified biochar was affected by pH and temperature, it was high under all of the tested conditions. Findings from this work indicated that alkali-modified biochars can be used as an alternative adsorbent for the removal of ammonium from wastewater.

Ab initio calculations of half-metallic ferromagnetism in Cr-doped MgSe and MgTe semiconductors

Energy Technology Data Exchange (ETDEWEB)

Noor, N.A. [Department of Physics, University of the Punjab, Quaid-e-Azam Campus, 54590 Lahore (Pakistan); Alay-e-Abbas, S.M. [Department of Physics, University of Sargodha, Sargodha 40100 (Pakistan); Department of Physics, GC University Faisalabad, Allama Iqbal Road, Faisalabad 38000 (Pakistan); Sohaib, M.U. [Lahore Development Authority, 54590 Lahore (Pakistan); Ghulam Abbas, S.M. [Department of Chemistry, University of Agriculture, Faisalabad 38040 (Pakistan); Shaukat, A., E-mail: schaukat@gmail.com [Department of Physics, University of Sargodha, Sargodha 40100 (Pakistan)

2015-01-15

The full-potential linear-augmented-plane-waves plus local-orbitals (FP-LAPW+lo) method has been employed for investigation of half-metallic ferromagnetism in Cr-doped ordered zinc-blende MgSe and MgTe semiconductors. Calculations of exchange and correlation (XC) effects have been carried out using generalized gradient approximation (GGA) and orbital independent modified Becke–Johnson potential coupled with local (spin) density approximation (mBJLDA). The thermodynamic stability of the compounds and their preferred magnetic orders have been analyzed in terms of the heat of formation and minimum total energy difference in ferromagnetic (FM) and anti-ferromagnetic (AFM) ordering, respectively. Calculated electronic properties reveal that the Cr-doping induces ferromagnetism in MgSe and MgTe which gives rise to a half-metallic (HM) gap at Fermi level (E{sub F}). Further, the electronic band structure is discussed in terms of s (p)–d exchange constants that are consistent with typical magneto-optical experiment and the behavior of charge spin densities is presented for understanding the bonding nature. Our results demonstrate that the higher effective potential for the spin-down case is responsible for p–d exchange splitting. Total magnetic moment (mainly due to Cr-d states) of these compounds is 4µ{sub B}. Importantly, the electronic properties and HM gap obtained using mBJLDA show remarkable improvement as compared to the results obtained using standard GGA functional. - Highlights: • Spin effect theoretical study on Cr-doped MgSe and MgTe is performed. • Half-metallic ferromagnetism in Cr{sub x}Mg{sub 1−x}Se and Cr{sub x}Mg{sub 1−x}Te is established. • Results of WC-GGA and mBJLDA are compared for performance. • HM gaps for Cr{sub x}Mg{sub 1−x}Se and Cr{sub x}Mg{sub 1−x}Te show nonlinear variation with x. • Important values of exchange splitting/constants and moments are reported.

Analgesic Efficacy of a New Immediate-Release/Extended-Release Formulation of Ibuprofen: Results From Single- and Multiple-Dose Postsurgical Dental Pain Studies.

Science.gov (United States)

Christensen, Steven; Paluch, Ed; Jayawardena, Shyamalie; Daniels, Stephen; Meeves, Suzanne

2017-05-01

Analgesic effects of ibuprofen immediate-release/extended-release (IR/ER) 600-mg tablets were evaluated in 2 randomized, double-blind, placebo-controlled dental pain studies. Patients 16-40 years old with moderate-severe pain following third-molar extraction received single-dose ibuprofen 600 mg IR/ER (formulation A or B), naproxen sodium 220 mg, or placebo (2:2:2:1; study 1) or 4 doses of ibuprofen 600 mg IR/ER (formulation A) or placebo (1:1; study 2). In study 1 (n = 196), mean (standard deviation [SD]) time-weighted sum of pain intensity difference scores for placebo, ibuprofen IR/ER A, ibuprofen IR/ER B, and naproxen, respectively, were 0.05 (9.2), 16.87 (9.4), 17.34 (10.5), and 12.66 (10.0) over 0-12 hours and -0.03 (4.1), 6.57 (4.4), 7.14 (5.2), and 5.14 (5.0) over 8-12 hours (all P ibuprofen IR/ER, respectively (P ibuprofen. Gastrointestinal adverse events predominated with placebo both after study medication administration and after rescue medication use, if applicable. Ibuprofen 600 mg IR/ER provided safe and effective analgesia after single and multiple doses. © 2016, The American College of Clinical Pharmacology.

Effectiveness, pharmacokinetics, and safety of a new sustained-release leuprolide acetate 3.75-mg depot formulation for testosterone suppression in patients with prostate cancer: a Phase III, open-label, international multicenter study.

Science.gov (United States)

Marberger, Michael; Kaisary, Amir V; Shore, Neal D; Karlin, Gary S; Savulsky, Claudio; Mis, Ricard; Leuratti, Chiara; Germa, Josep R

2010-04-01

A microencapsulated, sustained-release formulation of leuprolide acetate 3.75 mg has been developed. This study investigated the effectiveness, pharmacokinetics, and safety profile of a 1-month leuprolide acetate 3.75-mg depot formulation for suppressing testosterone concentrations in patients with prostate cancer. This was a Phase III, open-label, international multicenter clinical trial. Patients with prostate cancer who, in the judgment of the investigators, could benefit from androgen deprivation therapy received 6 monthly intramuscular injections of leuprolide acetate 3.75-mg depot. Plasma testosterone concentrations were determined at specific times throughout the study. The primary end point was the proportion of successful patients over the total number of evaluable patients (ie, patients with evaluable testosterone concentrations at all monthly assessments and no missing values due to treatment-related adverse events). Treatment success was defined as testosterone suppression below the clinical castration level (ie, n = 12), showed sustained release of leuprolide from the formulation. Values for AUC(0-t) calculated from day 0 to day 28, days 28 to 56, and days 56 to 84 were 25,976.5 (7892.0), 30,685.5 (9348.4), and 31,030.9 (10,745.0) pg/mL per day, respectively. The most common treatment-related adverse event was hot flashes (45.0% [72/160]). Fatigue, hyperhidrosis, night sweats, and headache each occurred in mg depot was effective in achieving and maintaining testosterone suppression and was well tolerated throughout the study in this cohort of patients with prostate cancer. ClinicalTrials.gov identifier: NCT00128531.

Release of a Poorly Soluble Drug from Hydrophobically Modified Poly (Acrylic Acid in Simulated Intestinal Fluids.

Directory of Open Access Journals (Sweden)

Patrik Knöös

Full Text Available A large part of new pharmaceutical substances are characterized by a poor solubility and high hydrophobicity, which might lead to a difference in drug adsorption between fasted and fed patients. We have previously evaluated the release of hydrophobic drugs from tablets based on Pemulen TR2 and showed that the release can be manipulated by adding surfactants. Here we further evaluate the possibility to use Pemulen TR2 in controlled release tablet formulations containing a poorly soluble substance, griseofulvin. The release is evaluated in simulated intestinal media that model the fasted state (FaSSIF medium or fed state (FeSSIF. The rheology of polymer gels is studied in separate experiments, in order to gain more information on possible interactions. The release of griseofulvin in tablets without surfactant varied greatly and the slowest release were observed in FeSSIF. Addition of SDS to the tablets eliminated the differences and all tablets showed a slow linear release, which is of obvious relevance for robust drug delivery. Comparing the data from the release studies and the rheology experiment showed that the effects on the release from the different media could to a large extent be rationalised as a consequence of the interactions between the polymer and the surfactants in the media. The study shows that Pemulen TR2 is a candidate for controlled release formulations in which addition of surfactant provides a way to eliminate food effects on the release profile. However, the formulation used needs to be designed to give a faster release rate than the tablets currently investigated.

The Tendencies of Piece Casting from Modified Irons

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Cinca Ionel Lupinca

2010-10-01

Full Text Available In this paper we have presented the metalographic studies made on the grey cast irons treated with complex modifying substances, type FeSiMgRE (Mg alloy and their influence on the compactness degree of graphite separations. For research and experiments, a melt of grey iron was produced in an induction furnace of a capacity of 5to, starting with a metallic charge made from 100% synthetic pig iron. We realized eight practical charge made modification, by using different combinations of modifying substance and in different concentrations. The addition of carbon to the melt was performed using electrode graphite powder in the metallic charge.

A pro-angiogenic degradable Mg-poly(lactic-co-glycolic acid) implant combined with rhbFGF in a rat limb ischemia model.

Science.gov (United States)

Bao, Hanmei; Lv, Feng; Liu, Tianjun

2017-12-01

Site-specific controlled release of exogenous angiogenic growth factors, such as recombinant human basic fibroblast growth factor (rhbFGF), has become a promising approach to improve peripheral vascular disease. Here, we have developed an implant composed of spiral magnesium (Mg) and a coating made using poly(lactic-co-glycolic acid) (PLGA) with encapsulated rhbFGF (Mg-PLGA-rhbFGF). The encapsulated protein could release continually for 4weeks with well preserved bioactivity. We compared the angiogenic effect produced by Mg-PLGA-rhbFGF with that of a PLGA implant loaded with rhbFGF (PLGA-rhbFGF). The incorporation of Mg in the implant raised the microclimate pH in the polymer, which preserved the stability of rhbFGF. Mg-PLGA-rhbFGF exhibited advantages over PLGA-rhbFGF implant in terms of a cytocompatibility evaluation. An in vivo angiogenesis test further confirmed the efficacy of released rhbFGF. HE, CD31 and α-SMA staining revealed that the controlled release of rhbFGF from the Mg-PLGA-rhbFGF implant was superior in promoting angiogenesis compared with that of the PLGA-rhbFGF implant. Four weeks post-implantation, the capillary density of the Mg-PLGA-rhbFGF group was significantly higher than that of the PLGA-rhbFGF, control and the normal group (pspiral magnesium and a coating made using poly(lactic-co-glycolic acid) (PLGA) with encapsulated rhbFGF (Mg-PLGA-rhbFGF). The preparation method does not involve any complex processes and results in a high encapsulation efficiency (approximately 100%). The degradation of metal Mg raise the microclimate pH in the PLGA polymer, which could well preserve the bioactivity of rhbFGF incorporated in the implant. Mg-PLGA-based, sustained local delivery of rhbFGF promotes post-ischemic angiogenesis and blood flow recovery in rat limb ischemic model. This work marks the first report for controlled release of rhbFGF in combination with metal Mg, and suggests potential therapeutic usefulness of Mg-PLGA-rhbFGF for tissue ischemia

Corrosion studies of modified organosilane coated magnesium-yttrium alloy in different environments

Energy Technology Data Exchange (ETDEWEB)

Xue Dingchuan [College of Engineering, University of Cincinnati, OH 45221 (United States); Tan Zongqing [Internal Medicine, College of Medicine, University of Cincinnati, OH 45221 (United States); Schulz, Mark J. [College of Engineering, University of Cincinnati, OH 45221 (United States); Vanooij, William J. [College of Engineering, University of Cincinnati, OH 45221 (United States); ECOSIL Technologies LLC, Fairfield, OH 45014 (United States); Sankar, Jagannathan [Biomedical Engineering Program, College of Engineering, North Carolina A and T State University, NC 27411 (United States); Yun Yeoheung, E-mail: yyun@ncat.edu [College of Engineering, University of Cincinnati, OH 45221 (United States); Biomedical Engineering Program, College of Engineering, North Carolina A and T State University, NC 27411 (United States); Dong Zhongyun [Internal Medicine, College of Medicine, University of Cincinnati, OH 45221 (United States)

2012-07-01

Magnesium (Mg) and its alloys have numerous potential applications as biodegradable implants, but the fast degradation rate of Mg alloys at the initial implanted stage could be a problem. This paper describes the modification of the water-based bis-[triethoxysilyl] ethane (BTSE) silane applied to the surface of magnesium-yttrium (Mg-4Y) to increase its corrosion resistance. Surface characterization by SEM, FTIR, and EDX showed that the hydrolysis and condensation of the silane resulted in a covalent bonding to the Mg-4Y surface. Corrosion behavior of the uncoated and coated Mg-4Y alloy was evaluated in different environments by using a novel self-developed corrosion probe. Based on the electrochemical results of DC polarization and electrochemical impedance spectroscopy (EIS), we conclude that the epoxy-modified BTSE silane coating successfully increases the corrosion resistance at the initial stage of implantation. The corrosion rates in the flesh of dead mice environments such as body cavity and subcutaneous tissue of the mice were lower than the corrosion rates in in vitro environments. - Highlights: Black-Right-Pointing-Pointer Modified silane was used on Mg-4Y for biological applications. Black-Right-Pointing-Pointer Modified silane-treated Mg-4Y increased its corrosion resistance in both In Vitro and In Vivo environments. Black-Right-Pointing-Pointer In Vitro testing environment is not consistent with In Vivo animal environment. Black-Right-Pointing-Pointer The modified silane mixture protecting mechanisms and its biocompatibility were discussed. Black-Right-Pointing-Pointer A novel three-electrode corrosion-monitoring probe was developed for realizing this work's In Vivo testing goals.

Geometry of modified release formulations during dissolution--influence on performance of dosage forms with diclofenac sodium.

Science.gov (United States)

Dorożyński, Przemysław; Kulinowski, Piotr; Jamróz, Witold; Juszczyk, Ewelina

2014-12-30

The objectives of the work included: presentation of magnetic resonance imaging (MRI) and fractal analysis based approach to comparison of dosage forms of different composition, structure, and assessment of the influence of the compositional factors i.e., matrix type, excipients etc., on properties and performance of the dosage form during drug dissolution. The work presents the first attempt to compare MRI data obtained for tablet formulations of different composition and characterized by distinct differences in hydration and drug dissolution mechanisms. The main difficulty, in such a case stems from differences in hydration behavior and tablet's geometry i.e., swelling, cracking, capping etc. A novel approach to characterization of matrix systems i.e., quantification of changes of geometrical complexity of the matrix shape during drug dissolution has been developed. Using three chosen commercial modified release tablet formulations with diclofenac sodium we present the method of parameterization of their geometrical complexity on the base of fractal analysis. The main result of the study is the correlation between the hydrating tablet behavior and drug dissolution - the increase of geometrical complexity expressed as fractal dimension relates to the increased variability of drug dissolution results. Copyright © 2014 Elsevier B.V. All rights reserved.

Sexual-incentive motivation and paced sexual behavior in female rats after treatment with drugs modifying dopaminergic neurotransmission.

Science.gov (United States)

Ellingsen, Ellinor; Agmo, Anders

2004-03-01

The effects of the dopamine receptor agonist apomorphine, the dopamine releaser amphetamine, and the dopamine receptor antagonist cis(Z)-flupenthixol on sexual-incentive motivation and on paced-mating behavior were studied in female rats. Apomorphine, in the doses of 0.125 and 0.5 mg/kg, showed a tendency to reduce incentive motivation. Ambulatory activity was inhibited, evidenced both by diminished distance moved and reduced velocity of movement. Amphetamine (0.25 and 1 mg/kg) and flupenthixol (0.25 and 0.5 mg/kg) failed to modify incentive motivation while stimulating and reducing ambulatory activity, respectively. In the mating test, apomorphine enhanced the latency to enter the male's half and reduced the number of proceptive behaviors. However, these effects were associated with the appearance of stereotyped sniffing. Amphetamine increased the propensity to escape from the male after a mount without having other effects. Flupenthixol augmented the duration of the lordosis posture. Neither amphetamine nor flupenthixol affected sniffing. These data show that facilitated dopaminergic neurotransmission stimulates neither paced female sexual behavior nor sexual-incentive motivation. Dopamine receptor blockade has slight consequences. It is concluded that dopamine is not a transmitter of major importance for unconditioned female sexual motivation and behavior.

Interactions of MK-801 with glutamate-, glutamine- and methamphetamine-evoked release of [3H]dopamine from striatal slices

International Nuclear Information System (INIS)

Bowyer, J.F.; Scallet, A.C.; Holson, R.R.; Lipe, G.W.; Slikker, W. Jr.; Ali, S.F.

1991-01-01

The interactions of MK-801 [(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5,10-imine], glutamate and glutamine with methamphetamine (METH)-evoked release of [ 3 H]dopamine were assessed in vitro to determine whether MK-801 inhibition of METH neurotoxicity might be mediated presynaptically, and to evaluate the effects of glutamatergic stimulation on METH-evoked dopamine release. MK-801 inhibition of glutamate- or METH-evoked dopamine release might reduce synaptic dopamine levels during METH exposure and decrease the formation of 6-hydroxydopamine or other related neurotoxins. Without Mg 2+ present, 40 microM and 1 mM glutamate evoked a N-methyl-D-aspartate receptor-mediated [ 3 H]dopamine and [ 3 H]metabolite (tritium) release of 3 to 6 and 12 to 16% of total tritium stores, respectively, from striatal slices. With 1.50 mM Mg 2+ present, 10 mM glutamate alone or in combination with the dopamine uptake blocker nomifensine released only 2.1 or 4.2%, respectively, of total tritium stores, and release was only partially dependent on N-methyl-D-aspartate-type glutamate receptors. With or without 1.50 mM Mg 2+ present, 0.5 or 5 microM METH evoked a substantial release of tritium (5-8 or 12-21% of total stores, respectively). METH-evoked dopamine release was not affected by 5 microM MK-801 but METH-evoked release was additive with glutamate-evoked release. Without Mg 2+ present, 1 mM glutamine increased glutamate release and induced the release of [ 3 H]dopamine and metabolites. Both 0.5 and 5 microM METH also increased tritium release with 1 mM glutamine present. When striatal slices were exposed to 5 microM METH this glutamine-evoked release of glutamate was increased more than 50%

Evaluating vertical concentration profile of carbon source released from slow-releasing carbon source tablets and in situ biological nitrate denitrification activity

Science.gov (United States)

Yeum, Y.; HAN, K.; Yoon, J.; Lee, J. H.; Song, K.; Kang, J. H.; Park, C. W.; Kwon, S.; Kim, Y.

2017-12-01

Slow-releasing carbon source tablets were manufactured during the design of a small-scale in situ biological denitrification system to reduce high-strength nitrate (> 30 mg N/L) from a point source such as livestock complexes. Two types of slow-releasing tablets, precipitating tablet (PT, apparent density of 2.0 g/mL) and floating tablet (FT), were prepared to achieve a vertically even distribution of carbon source (CS) in a well and an aquifer. Hydroxypropyl methylcellulose (HPMC) was used to control the release rate, and microcrystalline cellulose pH 101 (MCC 101) was added as a binder. The #8 sand was used as a precipitation agent for the PTs, and the floating agents for the FTs were calcium carbonate and citric acid. FTs floated within 30 min. and remained in water because of the buoyance from carbon dioxide, which formed during the acid-base reaction between citric acid and calcium carbonate. The longevities of PTs with 300 mg of HPMC and FTs with 400 mg of HPMC were 25.4 days and 37.3 days, respectively. We assessed vertical CS profile in a continuous flowing physical aquifer model (release test, RT) and its efficiency on biological nitrate denitrification (denitrification test, DT). During the RT, PTs, FTs and a tracer (as 1 mg rhodamine B/L) were initially injected into a well of physical aquifer model (PAM). Concentrations of CS and the tracer were monitored along the streamline in the PAM to evaluate vertical profile of CS. During the DT, the same experiment was performed as RT, except continuous injection of solution containing 30 mg N/L into the PAM to evaluate biological denitrification activity. As a result of RT, temporal profiles of CS were similar at 3 different depths of monitoring wells. These results suggest that simultaneous addition of PT and FT be suitable for achieving a vertically even distribution of the CS in the injection well and an aquifer. In DT, similar profile of CS was detected in the injection well, and nitrate was biologically

Synthesis of bio-based nanocomposites for controlled release of antimicrobial agents in food packaging

Science.gov (United States)

DeGruson, Min Liu

The utilization of bio-based polymers as packaging materials has attracted great attention in both scientific and industrial areas due to the non-renewable and nondegradable nature of synthetic plastic packaging. Polyhydroxyalkanoate (PHA) is a biobased polymer with excellent film-forming and coating properties, but exhibits brittleness, insufficient gas barrier properties, and poor thermal stability. The overall goal of the project was to develop the polyhydroxyalkanoate-based bio-nanocomposite films modified by antimicrobial agents with improved mechanical and gas barrier properties, along with a controlled release rate of antimicrobial agents for the inhibition of foodborne pathogens and fungi in food. The ability for antimicrobial agents to intercalate into layered double hydroxides depended on the nature of the antimicrobial agents, such as size, spatial structure, and polarity, etc. Benzoate and gallate anions were successfully intercalated into LDH in the present study and different amounts of benzoate anion were loaded into LDH under different reaction conditions. Incorporation of nanoparticles showed no significant effect on mechanical properties of polyhydroxybutyrate (PHB) films, however, significantly increased the tensile strength and elongation at break of polyhydroxybutyrate-co-valerate (PHBV) films. The effects of type and concentration of LDH nanoparticles (unmodified LDH and LDH modified by sodium benzoate and sodium gallate) on structure and properties of PHBV films were then studied. The arrangement of LDH in the bio-nanocomposite matrices ranged from exfoliated to phase-separated depending on the type and concentration of LDH nanoparticles. Intercalated or partially exfoliated structures were obtained using modified LDH, however, only phase-separated structures were formed using unmodified LDH. The mechanical (tensile strength and elongation at break) and thermo-mechanical (storage modulus) properties were significantly improved with low

Surface excess on MgO-doped TiO{sub 2} nanoparticles; Segregacao superficial de MgO em nanoparticulas de TiO{sub 2}

Energy Technology Data Exchange (ETDEWEB)

Gouvea, D.; Viana, B.H.; Miagava, J., E-mail: dgouvea@usp.br, E-mail: bhernardov@gmail.com, E-mail: joice.mgv@gmail.com [Universidade de Sao Paulo (USP), SP (Brazil). Dept. de Engenharia Metalurgica e de Materiais. Lab. de Processos Ceramicos

2016-10-15

Anatase has been the subject of several recent investigations partly as consequence of its interesting catalytic properties. Additives such as MgO have been introduced to improve the performance of the photocatalytic TiO{sub 2}. However, the physical-chemistry of these oxides systems and their relationship with properties are poorly understood. In this work, nanoparticles of xMgO-(1-x)TiO{sub 2} (0≤ x≤ 0.05) were synthesized by the polymeric precursor method at 500 °C for 15 h. XRD results showed that only anatase phase was obtained and the crystallite size decreases with increased MgO concentration. Magnesia surface excess was calculated by washing powders with HNO{sub 3} and the soluble Mg ions concentration determined by chemical analysis. FTIR analysis confirms that the acid washing modified the particle surface. Therefore, it is proposed that the reduction of the crystallite size occurs due to segregation of MgO on TiO{sub 2} nanoparticles surfaces. (author)

Electrical stimulation of the isolated rat intestine in the presence of nutrient stimulus enhances glucagon-like peptide-1 release

International Nuclear Information System (INIS)

Schwartz, Ann; Ort, Tatiana; Kajekar, Radhika; Hornby, Pamela J; Wade, Paul R

2010-01-01

The release of small intestinal hormones by constituents of ingested food, such as fatty acids, is integral to post-prandial responses that reduce food intake. Recent evidence suggests that small intestinal electrical stimulation reduces food intake, although the mechanism of action is debated. To test the hypothesis that intestinal stimulation directly alters hormone release locally we used isolated rat distal ileum and measured glucagon-like peptide-1 (GLP-1) released in the presence or absence of linoleic acid (LA) and electrical field stimulation (EFS). Intact segments were oriented longitudinally between bipolar stimulating electrodes in organ bath chambers containing modified Krebs–Ringers bicarbonate (KRB) buffer including protease inhibitors. Incubation in LA (3 mg ml −1 ) for 45 min increased GLP-1 concentration (21.9 ± 2.6 pM versus KRB buffer alone 3.6 ± 0.1 pM). Eleven electrical stimulation conditions were tested. In the presence of LA none of the stimulation conditions inhibited LA-evoked GLP-1 release, whereas two high frequency short pulse widths (14 V, 20 Hz, 5 ms and 14 V, 40 Hz, 5 ms) and one low frequency long pulse width (14 V, 0.4 Hz, 300 ms) EFS conditions enhanced LA-evoked GLP-1 release by >250%. These results are consistent with a local effect of intestinal electrical stimulation to enhance GLP-1 release in response to luminal nutrients in the intestines. Enhancing hormone release could improve the efficacy of intestinal electrical stimulation and provide a potential treatment for obesity and metabolic conditions

Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

International Nuclear Information System (INIS)

Li, Jian-wei; Zhao, Chong-jun; Feng, Chun; Yu, Guang-hua; Zhou, Zhongfu

2015-01-01

Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress

Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

Science.gov (United States)

Li, Jian-wei; Zhao, Chong-jun; Feng, Chun; Zhou, Zhongfu; Yu, Guang-hua

2015-08-01

Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress.

Impact of interface manipulation of oxide on electrical transport properties and low-frequency noise in MgO/NiFe/MgO heterojunctions

Energy Technology Data Exchange (ETDEWEB)

Li, Jian-wei [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhao, Chong-jun; Feng, Chun; Yu, Guang-hua [School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Zhou, Zhongfu [School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

2015-08-15

Low-frequency noise and magnetoresistance in sputtered-deposited Ta(5 nm)/MgO (3 nm)/NiFe(10 nm)/MgO(3 nm)/Ta(3 nm) films have been measured as a function of different annealing times at 400°C. These measurements did not change synchronously with annealing time. A significant increase in magnetoresistance is observed for short annealing times (of the order of minutes) and is correlated with a relatively small reduction in 1/f noise. In contrast, a significant reduction in 1/f noise is observed for long annealing times (of the order of hours) accompanied by a small change in magnetoresistance. After annealing for 2 hours, the 1/f noise decreases by three orders of magnitude. Transmission electron microscopy and slow positron annihilation results implicate the cause being micro-structural changes in the MgO layers and interfaces following different annealing times. The internal vacancies in the MgO layers gather into vacancy clusters to reduce the defect density after short annealing times, whereas the MgO/NiFe and the NiFe/MgO interfaces improve significantly after long annealing times with the amorphous MgO layers gradually crystallizing following the release of interfacial stress.

78 FR 66009 - Determination That INVEGA (Paliperidone) Extended-Release Tablet, 12 Milligrams, Was Not...

Science.gov (United States)

2013-11-04

...] Determination That INVEGA (Paliperidone) Extended-Release Tablet, 12 Milligrams, Was Not Withdrawn From Sale for... Food and Drug Administration (FDA) has determined that INVEGA (paliperidone) extended-release tablet...-release tablet, 12 mg, if all other legal and regulatory requirements are met. FOR FURTHER INFORMATION...

Simultaneous Intercalation of 1-Naphthylacetic Acid and Indole-3-butyric Acid into Layered Double Hydroxides and Controlled Release Properties

Directory of Open Access Journals (Sweden)

Shifeng Li

2014-01-01

Full Text Available Controlled release formulations have been shown to have potential in overcoming the drawbacks of conventional plant growth regulators formulations. A controlled-release formulation of 1-naphthylacetic acid (NAA and indole-3-butyric acid (IBA simultaneous intercalated MgAl-layered double hydroxides (LDHs was prepared. The synthetic nanohybrid material was characterized by various techniques, and release kinetics was studied. NAA and IBA anions located in the gallery of MgAl-LDHs with bilayer arrangement, and the nanohybrids particles were of typical plate-like shape with the lateral size of 50–100 nm. The results revealed that NAA and IBA have been intercalated into the interlayer spaces of MgAl-LDHs. The release of NAA and IBA fits pseudo-second-order model and is dependent on temperature, pH value, and release medium. The nanohybrids of NAA and IBA simultaneously intercalated in LDHs possessed good controlled release properties.

Hydrogen Storage and Release Properties of Transition Metal-Added Magnesium Hydride Alloy Fabricated by Grinding in a Hydrogen Atmosphere

Energy Technology Data Exchange (ETDEWEB)

Kwon, Sung Nam; Song, Myoung Youp [Chonbuk National University, Jeonju (Korea, Republic of); Park, Hye Ryoung [Chonnam National University, Gwangju (Korea, Republic of)

2016-07-15

90 wt% MgH{sub 2}+5 wt% Ni+2.5 wt% Fe+2.5 wt% Ti (called MgH{sub 2}+Ni+Fe+Ti), a hydrogen storage and release material, was fabricated by grinding in a hydrogen atmosphere, and then its quantities of stored and released hydrogen as a function of time were examined. A nanocrystalline MgH{sub 2}+Ni+Fe+Ti specimen was made by grinding in a hydrogen atmosphere and subsequent hydrogen storage-release cycling. The crystallite size of Mg and the strain of the Mg crystallite after ten hydrogen storage-release cycles, which were obtained using the Williamson-Hall method, were 38.6 (±1.4) nm and 0.025 (±0.0081) %, respectively. The MgH{sub 2}+Ni+Fe+Ti sample after the process of grinding in a hydrogen atmosphere was highly reactive with hydrogen. The sample exhibited an available storage capacity of hydrogen (the amount of hydrogen stored during 60 minutes) of about 5.7 wt%. At the first cycle, the MgH2+Ni+Fe+Ti sample stored hydrogen of 5.53 wt% in 5 minutes, 5.66 wt% in 10 minutes and 5.73 wt% in 60 minutes at 573 K and 12 bar of hydrogen. The MgH{sub 2}+Ni+Fe+Ti after activation released hydrogen of 0.56 wt% in 5 minutes, 1.26 wt% in 10 minutes, 2.64 wt% in 20 minutes, 3.82 wt% in 30 minutes, and 5.03 wt% in 60 minutes.

Core/shell PLGA microspheres with controllable in vivo release profile via rational core phase design.

Science.gov (United States)

Yu, Meiling; Yao, Qing; Zhang, Yan; Chen, Huilin; He, Haibing; Zhang, Yu; Yin, Tian; Tang, Xing; Xu, Hui

2018-02-27

Highly soluble drugs tend to release from preparations at high speeds, which make them need to be taken at frequent intervals. Additionally, some drugs need to be controlled to release in vivo at certain periods, so as to achieve therapeutic effects. Thus, the objective of this study is to design injectable microparticulate systems with controllable in vivo release profile. Biodegradable PLGA was used as the matrix material to fabricate microspheres using the traditional double emulsification-solvent evaporation method as well as improved techniques, with gel (5% gelatine or 25% F127) or LP powders as the inner phases. Their physicochemical properties were systemically investigated. Microspheres prepared by modified methods had an increase in drug loading (15.50, 16.72, 15.66%, respectively) and encapsulation efficiencies (73.46, 79.42, 74.40%, respectively) when compared with traditional methods (12.01 and 57.06%). The morphology of the particles was characterized by optical microscope (OM) and scanning electron microscopy (SEM), and the amorphous nature of the encapsulated drug was confirmed by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. To evaluate their release behaviour, the in vitro degradation, in vitro release and in vivo pharmacodynamics were subsequently studied. Traditional microspheres prepared in this study with water as the inner phase had a relatively short release period within 16 d when compared with modified microspheres with 5% gelatine as the inner phase, which resulted in a smooth release profile and appropriate plasma LP concentrations over 21 d. Thus this type of modified microspheres can be better used in drugs requiring sustained release. The other two formulations containing 25% F127 and LP micropowders presented two-stage release profiles, resulting in fluctuant plasma LP concentrations which may be suitable for drugs requiring controlled release. All the results suggested that drug release rates from

Antimony leaching release from brake pads: Effect of pH, temperature and organic acids.

Science.gov (United States)

Hu, Xingyun; He, Mengchang; Li, Sisi

2015-03-01

Metals from automotive brake pads pollute water, soils and the ambient air. The environmental effect on water of antimony (Sb) contained in brake pads has been largely untested. The content of Sb in one abandoned brake pad reached up to 1.62×10(4) mg/kg. Effects of initial pH, temperature and four organic acids (acetic acid, oxalic acid, citric acid and humic acid) on Sb release from brake pads were studied using batch reactors. Approximately 30% (97 mg/L) of the total Sb contained in the brake pads was released in alkaline aqueous solution and at higher temperature after 30 days of leaching. The organic acids tested restrained Sb release, especially acetic acid and oxalic acid. The pH-dependent concentration change of Sb in aqueous solution was best fitted by a logarithmic function. In addition, Sb contained in topsoil from land where brake pads were discarded (average 9×10(3) mg/kg) was 3000 times that in uncontaminated soils (2.7±1 mg/kg) in the same areas. Because potentially high amounts of Sb may be released from brake pads, it is important that producers and environmental authorities take precautions. Copyright © 2015. Published by Elsevier B.V.

Local control of striatal dopamine release

Directory of Open Access Journals (Sweden)

Roger eCachope

2014-05-01

Full Text Available The mesolimbic and nigrostriatal dopamine (DA systems play a key role in the physiology of reward seeking, motivation and motor control. Importantly, they are also involved in the pathophysiology of Parkinson’s and Huntington’s disease, schizophrenia and addiction. Control of DA release in the striatum is tightly linked to firing of DA neurons in the ventral tegmental area (VTA and the substantia nigra (SN. However, local influences in the striatum affect release by exerting their action directly on axon terminals. For example, endogenous glutamatergic and cholinergic activity is sufficient to trigger striatal DA release independently of cell body firing. Recent developments involving genetic manipulation, pharmacological selectivity or selective stimulation have allowed for better characterization of these phenomena. Such termino-terminal forms of control of DA release transform considerably our understanding of the mesolimbic and nigrostriatal systems, and have strong implications as potential mechanisms to modify impaired control of DA release in the diseased brain. Here, we review these and related mechanisms and their implications in the physiology of ascending DA systems.

Flexible MgO Barrier Magnetic Tunnel Junctions.

Science.gov (United States)

Loong, Li Ming; Lee, Wonho; Qiu, Xuepeng; Yang, Ping; Kawai, Hiroyo; Saeys, Mark; Ahn, Jong-Hyun; Yang, Hyunsoo

2016-07-01

Flexible MgO barrier magnetic tunnel junction (MTJ) devices are fabricated using a transfer printing process. The flexible MTJ devices yield significantly enhanced tunneling magnetoresistance of ≈300% and improved abruptness of switching, as residual strain in the MTJ structure is released during the transfer process. This approach could be useful for flexible electronic systems that require high-performance memory components. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Preparation of novel functional Mg/O/PCL/ZnO composite biomaterials and their corrosion resistance

International Nuclear Information System (INIS)

Xi, Zhongxian; Tan, Cui; Xu, Lan; Yang, Na; Li, Qing

2015-01-01

Highlights: • Novel functional Mg/O/PCL/ZnO composite biomaterials were prepared. • The biomaterials were prepared by anodization treatment and dip-coating technique. • The composite biomaterials were smooth and with low porosity. • The prepared biomaterials have good corrosion resistance in SBF. • The composite biomaterials can release zinc ion to promote bone formation. - Abstract: In this study, novel and functional Mg/O/PCL/ZnO (magnesium/anodic film/poly(ε-caprolactone)/zinc oxide) composite biomaterials for enhancing the bioactivity and biocompatibility of the implant was prepared by using anodization treatment and dip-coating technique. The surface morphology, microstructure, adhesion strength and corrosion resistance of the composite biomaterials were investigated using scanning electron microscopy (SEM), adhesion measurements, electrochemical tests and immersion tests respectively. In addition, the biocompatible properties of Mg (magnesium), Mg/PCL (magnesium/poly(ε-caprolactone)) and Mg/O/PCL (magnesium/anodic film/poly(ε-caprolactone)) samples were also investigated. The results show that the Mg/O/PCL/ZnO composite biomaterials were with low porosity and with the ZnO powders dispersed in PCL uniformly. The adhesion tests suggested that Mg/O/PCL/ZnO composite biomaterials had better adhesion strength than that of Mg/PCL composite biomaterials obviously. Besides, an in vitro test for corrosion demonstrated that the Mg/O/PCL/ZnO composite biomaterials had good corrosion resistance and zinc ion was released obviously in SBF

Optoelectronic properties of XIn{sub 2}S{sub 4} (X = Cd, Mg) thiospinels through highly accurate all-electron FP-LAPW method coupled with modified approximations

Energy Technology Data Exchange (ETDEWEB)

Yousaf, Masood [Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Dalhatu, S.A. [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Murtaza, G. [Department of Physics, Islamia College, Peshawar, KPK (Pakistan); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 Mascara (Algeria); Sajjad, M. [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Musa, A. [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Rahnamaye Aliabad, H.A. [Department of Physics, Hakim Sabzevari University (Iran, Islamic Republic of); Saeed, M.A., E-mail: saeed@utm.my [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)

2015-03-15

Highlights: • Highly accurate all-electron FP-LAPW+lo method is used. • New physical parameters are reported, important for the fabrication of optoelectronic devices. • A comparative study that involves FP-LAPW+lo method and modified approximations. • Computed band gap values have good agreement with the experimental values. • Optoelectronic results of fundamental importance can be utilized for the fabrication of devices. - Abstract: We report the structural, electronic and optical properties of the thiospinels XIn{sub 2}S{sub 4} (X = Cd, Mg), using highly accurate all-electron full potential linearized augmented plane wave plus local orbital method. In order to calculate the exchange and correlation energies, the method is coupled with modified techniques such as GGA+U and mBJ-GGA, which yield improved results as compared to the previous studies. GGA+SOC approximation is also used for the first time on these compounds to examine the spin orbit coupling effect on the band structure. From the analysis of the structural parameters, robust character is predicted for both materials. Energy band structures profiles are fairly the same for GGA, GGA+SOC, GGA+U and mBJ-GGA, confirming the indirect and direct band gap nature of CdIn{sub 2}S{sub 4} and MgIn{sub 2}S{sub 4} materials, respectively. We report the trend of band gap results as: (mBJ-GGA) > (GGA+U) > (GGA) > (GGA+SOC). Localized regions appearing in the valence bands for CdIn{sub 2}S{sub 4} tend to split up nearly by ≈1 eV in the case of GGA+SOC. Many new physical parameters are reported that can be important for the fabrication of optoelectronic devices. Optical spectra namely, dielectric function (DF), refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and electron loss function are discussed. Optical’s absorption edge is noted to be 1.401 and 1.782 for CdIn{sub 2}S{sub 4} and MgIn{sub 2}S{sub 4}, respectively. The

A phase III randomized controlled study on the efficacy and improved bowel function of prolonged-release (PR) oxycodone-naloxone (up to 160/80 mg daily) vs oxycodone PR.

Science.gov (United States)

Dupoiron, D; Stachowiak, A; Loewenstein, O; Ellery, A; Kremers, W; Bosse, B; Hopp, M

2017-10-01

Oxycodone/naloxone (OXN PR) is a prolonged-release formulation containing oxycodone and naloxone in a 2:1 ratio. This study aimed to evaluate the tolerability and efficacy of doses up to OXN160/80 mg PR compared with oxycodone prolonged-release formulation (OxyPR) in a randomised controlled trial. Two hundred and forty-three patients were randomised to treatment with OXN PR (n = 123) or OxyPR (n = 120) during the 5-week double-blind study. Measured were: opioid-induced constipation [bowel function index score (BFI)]; analgesic efficacy (NRS 0-10); daily laxative rescue medication use; rescue medication use, and the number of complete spontaneous bowel movements (CSBMs) per week. A subanalysis was conducted in cancer patients. Greater reductions in mean BFI scores were reported for the OXN PR group compared with OxyPR from Week 1 onwards; at Week 5 the mean change from baseline was -32.5 versus -14.2. Average 24-h pain scores were low and remained stable in the range 3-4 in both treatment groups. Analgesic rescue medication use was similar between the groups. Patients receiving OXN PR used significantly lower mean daily doses of laxative rescue medication than those receiving OxyPR (P = 0.006). The number of CSBM in the OXN PR group approximately doubled compared with a 25% decrease in the OxyPR group. Comparable results to the total study population were reported in the cancer patient subgroup. OXN PR in daily doses of up to 160/80 mg significantly improves bowel function compared with equivalent doses of OxyPR while still providing comparable analgesic efficacy. Effective analgesia can be achieved using oxycodone/naloxone PR up to 160/80 mg daily without compromising bowel function. A similar outcome was reported in cancer and non-cancer patients. © 2017 The Authors. European Journal of Pain published by John Wiley & Sons Ltd on behalf of European Pain Federation - EFIC®.

Preparation of Mg2FeH6 Nanoparticles for Hydrogen Storage Properties

Directory of Open Access Journals (Sweden)

N. A. Niaz

2013-01-01

Full Text Available Magnesium (Mg and iron (Fe nanoparticles are prepared by thermal decomposition of bipyridyl complexes of metals. These prepared Mg-Fe (2 : 1 nanoparticles are hydrogenated under 4 MPa hydrogen pressure and 673 K for 48 hours to achieve Mg2FeH6. Their structural analysis was assessed by applying manifold techniques. The hydrogen storage properties of prepared compound were measured by Sieverts type apparatus. The desorption kinetics were measured by high pressure thermal desorption spectrometer (HP-TDS. More than 5 wt% hydrogen released was obtained by the Mg2FeH6 within 5 min, and during rehydrogenation very effective hydrogen absorption rate was observed by the compound.

The effect of ketamine on intraspinal acetylcholine release

DEFF Research Database (Denmark)

Abelson, Klas S P; Goldkuhl, Renée Röstlinger; Nylund, Anders

2006-01-01

The general anaesthetic ketamine affects the central cholinergic system in several manners, but its effect on spinal acetylcholine release, which may be an important transmitter in spinal antinociception, is unknown. This study aimed to investigate the effect of ketamine on spinal acetylcholine...... release. Microdialysis probes were placed intraspinally in male rats, and acetylcholine was quantified with HPLC. Anaesthesia was switched from isoflurane (1.3%) to ketamine (150 mg/kg h), which resulted in a 500% increased acetylcholine release. The increase was attenuated during nicotinic receptor...... blockade (50 microM mecamylamine). The nicotinic receptor agonist epibatidine (175 microM) produced a ten-fold higher relative increase of acetylcholine release during isoflurane anaesthesia compared to ketamine anaesthesia (270% to 27%). Intraspinal administration of ketamine and norketamine both...

Preparation and Characterization of Novel Gellan Gum Hydrogels Suitable for Modified Drug Release

Directory of Open Access Journals (Sweden)

Pietro Matricardi

2009-09-01

Full Text Available Innovative hydrogels obtained by physical and chemical crosslinking of deacylated Gellan gum have been characterized in terms of water uptake, rheological properties and compressibility, and the behaviour of the tested materials, according to the type of the obtained network, is thoroughly discussed. The release from the various gels of loaded model molecules of different steric hindrance was also investigated and the trend of the release profiles has been related to the structures proposed for the physical and the chemical hydrogel.

A randomized controlled trial to compare the effects of sulphonylurea gliclazide MR (modified release) and the DPP-4 inhibitor vildagliptin on glycemic variability and control measured by continuous glucose monitoring (CGM) in Brazilian women with type 2 diabetes.

Science.gov (United States)

Vianna, Andre Gustavo Daher; Lacerda, Claudio Silva; Pechmann, Luciana Muniz; Polesel, Michelle Garcia; Marino, Emerson Cestari; Faria-Neto, Jose Rocha

2018-05-01

This study aims to evaluate whether there is a difference between the effects of vildagliptin and gliclazide MR (modified release) on glycemic variability (GV) in women with type 2 diabetes (T2DM) as evaluated by continuous glucose monitoring (CGM). An open-label, randomized study was conducted in T2DM women on steady-dose metformin monotherapy which were treated with 50 mg vildagliptin twice daily or 60-120 mg of gliclazide MR once daily. CGM and GV indices calculation were performed at baseline and after 24 weeks. In total, 42 patients (age: 61.9 ± 5.9 years, baseline glycated hemoglobin (HbA1c): 7.3 ± 0.56) were selected and 37 completed the 24-week protocol. Vildagliptin and gliclazide MR reduced GV, as measured by the mean amplitude of glycemic excursions (MAGE, p = 0.007 and 0.034, respectively). The difference between the groups did not reach statistical significance. Vildagliptin also significantly decreased the standard deviation of the mean glucose (SD) and the mean of the daily differences (MODD) (p = 0.007 and 0.030). Vildagliptin and gliclazide MR similarly reduced the MAGE in women with T2DM after 24 weeks of treatment. Further studies are required to attest differences between vildagliptin and gliclazide MR regarding glycemic variability. Copyright © 2018 Elsevier B.V. All rights reserved.

Efficacy of 5MG and 10MG rosuvastatin in type-2 diabetes mellitus with hypercholesteroalemia

International Nuclear Information System (INIS)

Ullah, F.; Rahim, F.; Rahman, S.U.; Ashfaq, M.; Afridi, A.K.

2015-01-01

Background: Coronary Heart Disease (CHD) is the most important complication and the leading cause of death in patients with type 2 diabetes mellitus (T2DM). Hypercholesterolemia is an important modifiable risk factor for CHD. Statins are the first line drugs for the treatment of hypercholesterolemia in DM. Comparative studies between different statins are available but different doses of the same statin have not been compared in our population. The objective of this study is to compare mean reduction in serum LDL-C level after using 5mg and 10mg of rosuvastatin among T2DM patients with hypercholesterolemia. This study will help finding lowest effective dose of rosuvastatin to achieve internationally set low density lipoprotein cholesterol (LDL-C) goals. Method: A total of 82 patients with T2DM having fasting LDL-C levels equal or more than 100mg/dl were randomly allocated into two groups with 41 patients in each group. Baseline fasting serum LCL-C levels were obtained in all patients. Group A received 5mg while group B received 10mg of rosuvastatin daily at night. After 6 weeks, fasting LDL-C levels were obtained and analysed to compare the mean±SD reduction of LDL-C levels in both groups. Results: Baseline mean±SD LDL-C levels in group A and group B were 134.12±30.02 and 143.49±32.01 respectively (p 0.176). Follow up mean ± SD LDL-C levels were 81.59±28.47 and 83.24±36.06 respectively (p 0.818). Mean ± SD reduction in LDL-C levels from baseline levels in group A and group B were 52.51±19.49 and 60.20±24.09 (p 0.116). Conclusion: Rosuvastatin 5mg is as effective as 10mg in reducing the LDL-C levels in type 2 diabetic patients with hypercholesterolemia. (author)

Thermochemical Storage of Middle Temperature Wasted Heat by Functionalized C/Mg(OH2 Hybrid Materials

Directory of Open Access Journals (Sweden)

Emanuela Mastronardo

2017-01-01

Full Text Available For the thermochemical performance implementation of Mg(OH2 as a heat storage medium, several hybrid materials have been investigated. For this study, high-performance hybrid materials have been developed by exploiting the authors’ previous findings. Expanded graphite (EG/carbon nanotubes (CNTs-Mg(OH2 hybrid materials have been prepared through Mg(OH2 deposition-precipitation over functionalized, i.e., oxidized, or un-functionalized EG or CNTs. The heat storage performances of the carbon-based hybrid materials have been investigated through a laboratory-scale experimental simulation of the heat storage/release cycles, carried out by a thermogravimetric apparatus. This study offers a critical evaluation of the thermochemical performances of developed materials through their comparison in terms of heat storage and output capacities per mass and volume unit. It was demonstrated that both EG and CNTs improves the thermochemical performances of the storage medium in terms of reaction rate and conversion with respect to pure Mg(OH2. With functionalized EG/CNTs-Mg(OH2, (i the potential heat storage and output capacities per mass unit of Mg(OH2 have been completely exploited; and (ii higher heat storage and output capacities per volume unit were obtained. That means, for technological applications, as smaller volume at equal stored/released heat.

Preparation and characterization of genipin-cross-linked silk fibroin/chitosan sustained-release microspheres

Directory of Open Access Journals (Sweden)

Zeng SG

2015-05-01

Full Text Available Shuguang Zeng,1,* Manwen Ye,1,2,* Junqi Qiu,1 Wei Fang,1 Mingdeng Rong,1 Zehong Guo,1 Wenfen Gao11Department of Oral and Maxillofacial Surgery, Guangdong Provincial Stomatological Hospital, Southern Medical University, 2Department of Stomatology, Guangdong Women and Children Hospital, Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China*These authors contributed equally to this workAbstract: We report the effects of distinct concentrations of genipin and silk fibroin (SF:chitosan (CS ratios on the formation of SF–CS composite microspheres. We selected microspheres featuring an SF:CS ratio of 1:1, encapsulated various concentrations of bovine serum albumin (BSA, and then compared their encapsulation efficiency and sustained-release rate with those of pure CS microspheres. We determined that the following five groups of microspheres were highly spherical and featured particle sizes ranging from 70 µm to 147 µm: mass ratio of CS:SF =1:0.5, 0.1 g or 0.5 g genipin; CS:SF =1:1, 0.05 g or 1 g genipin; and CS:SF =1:2, 0.5 g genipin. The microspheres prepared using 1:1 CS:SF ratio and 0.05 g genipin in the presence of 10 mg, 20 mg, and 50 mg of BSA exhibited encapsulation efficiencies of 50.16%±4.32%, 56.58%±3.58%, and 42.19%±7.47%, respectively. Fourier-transform infrared spectroscopy (FTIR results showed that SF and CS were cross-linked and that the α-helices and random coils of SF were converted into β-sheets. BSA did not chemically react with CS or SF. Moreover, thermal gravimetric analysis (TGA results showed that the melting point of BSA did not change, which confirmed the FTIR results, and X-ray diffraction results showed that BSA was entrapped in microspheres in a noncrystalline form, which further verified the TGA and FTIR data. The sustained-release microspheres prepared in the presence of 10 mg, 20 mg, and 50 mg of BSA burst release 30.79%±3.43%, 34.41%±4.46%, and 41.75%±0.96% of the

Modified thermoresponsive Poloxamer 407 and chitosan sol-gels as potential sustained-release vaccine delivery systems.

Science.gov (United States)

Kojarunchitt, Thunjiradasiree; Baldursdottir, Stefania; Dong, Yao-Da; Boyd, Ben J; Rades, Thomas; Hook, Sarah

2015-01-01

Thermoresponsive, particle-loaded, Poloxamer 407 (P407)-Pluronic-R® (25R4) or chitosan-methyl cellulose (MC) formulations were developed as single-dose, sustained release vaccines. The sol-gels, loaded either with a particulate vaccine (cubosomes) or soluble antigen (ovalbumin) and adjuvants (Quil A and monophosphoryl lipid A), were free-flowing liquids at room temperature and formed stable gels at physiological temperatures. Rheological results showed that both systems meet the criteria of being thermoresponsive gels. The P407-25R4 sol-gels did not significantly sustain the release of antigen in vivo while the chitosan-MC sol-gels sustained the release of antigen up to at least 14 days after administration. The chitosan-MC sol-gels stimulated both cellular and humoral responses. The inclusion of cubosomes in the sol-gels did not provide a definitive beneficial effect. Further analysis of the formulations with small-angle X-ray scattering (SAXS) revealed that while cubosomes were stable in chitosan-MC gels they were not stable in P407-25R4 formulations. The reason for the mixed response to cubosome-loaded vehicles requires more investigation, however it appears that the cubosomes did not facilitate synchronous vaccine release and may in fact retard release, reducing efficacy in some cases. From these results, chitosan-MC sol-gels show potential as sustained release vaccine delivery systems, as compared to the P407-25R4 system that had a limited ability to sustain antigen release. Copyright © 2014 Elsevier B.V. All rights reserved.

Prolactin releasing effect of sulpiride isomers in rats and man

Energy Technology Data Exchange (ETDEWEB)

Mueller, E E; Stefanini, E; Spano, P F [Cagliari Univ. (Italy). Inst. of Pharmacology and Pharmacognosy; Camanni, F; Massara, F [Turin Univ. (Italy). Chair of Endocrinology; Locatelli, V; Cocchi, D

1979-01-01

Sulpiride, an antipsychotropic drug of the benzamide class, reportedly displaces stereospecifically (/sup 3/H)-butyrophenones from putative dopamine (DA) binding sites in rat striatum. To evaluate if sulpiride displays the same stereospecifity in the inhibition of pituitary DA receptors, the effect of the two(-)-and (+)-sulpiride isomers was tested with regard to their ability to stimulate prolactin (PRL) secretion in rats and man and to displace (/sup 3/H)-spiroperidol bound to rat anterior pituitary receptors. In male rats, (-)-sulpiride at doses of 0.1 and 0.1 mg/kg i.p., induced a maximum PRL-releasing effect, not different from that evoked by a dose of 10 mg/kg of the compound. (+)-Sulpiride was active only at the dose of 10mg/kg i.p., and its PRL-releasing effect was superimposable to that evoked by the same dose of (-)-sulpiride. Similarily, in 8 normal subjects (4 men and 4 women) only (-)-sulpiride was active as PRL releaser when the low dose of 0.25 mg i.v. was used; when the higher dose of sulpiride was used (4.0 mg i.v.), it induced a rise in plasma PRL of the same entity for both isomers at early post-injection times (15-30 min) but greater with the (-)-isomer at the following time intervals (45-120 min). (-)-Sulpiride displaced (/sup 3/H)-spiroperidol bound to rat anterior pituitary homogenates with a potency about 100 times greater as that showed by (+)-sulpiride. In all, these data indicate that sulpiride isomers display at the level of pituitary DA receptors for PRL control the same stereospecifity exhibited on a population of striatal DA receptors.

Synthesis of fatty acid methyl ester from crude jatropha (Jatropha curcas Linnaeus) oil using aluminium oxide modified Mg-Zn heterogeneous catalyst.

Science.gov (United States)

Olutoye, M A; Hameed, B H

2011-06-01

The synthesis of fatty acid methyl esters (FAME) as a substitute to petroleum diesel was investigated in this study from crude jatropha oil (CJO), a non-edible, low-cost alternative feedstock, using aluminium modified heterogeneous basic oxide (Mg-Zn) catalyst. The transesterification reaction with methanol to methyl esters yielded 94% in 6h with methanol-oil ratio of 11:1, catalyst loading of 8.68 wt.% at 182°C and the properties of CJO fuel produced were determine and found to be comparable to the standards according to ASTM. In the range of experimental parameters investigated, it showed that the catalyst is selective to production of methyl esters from oil with high free fatty acid (FFA) and water content of 7.23% and 3.28%, respectively in a single stage process. Thus, jatropha oil is a promising feedstock for methyl ester production and large scale cultivation will help to reduce the product cost. Copyright © 2011 Elsevier Ltd. All rights reserved.

Corrosion Resistance of the Superhydrophobic Mg(OH2/Mg-Al Layered Double Hydroxide Coatings on Magnesium Alloys

Directory of Open Access Journals (Sweden)

Fen Zhang

2016-04-01

Full Text Available Coatings of the Mg(OH2/Mg-Al layered double hydroxide (LDH composite were formed by a combined co-precipitation method and hydrothermal process on the AZ31 alloy substrate in alkaline condition. Subsequently, a superhydrophobic surface was successfully constructed to modify the composite coatings on the AZ31 alloy substrate using stearic acid. The characteristics of the composite coatings were investigated by means of X-ray diffractometer (XRD, Fourier transform infrared spectroscopy (FTIR, X-ray photoelectron spectroscopy (XPS, scanning electronic microscope (SEM and contact angle (CA. The corrosion resistance of the coatings was assessed by potentiodynamic polarization, the electrochemical impedance spectrum (EIS, the test of hydrogen evolution and the immersion test. The results showed that the superhydrophobic coatings considerably improved the corrosion resistant performance of the LDH coatings on the AZ31 alloy substrate.

Ionizing radiation effects in MgAl sub 2 O sub 4. Efecto de la radiacion ionizante en MgAl2 O4

Energy Technology Data Exchange (ETDEWEB)

Ibarra, A.

1990-11-01

The effect of ionizing radiation in MgAl{sub 2}O{sub 4} has been studied, paying special interest to the influence of the high concentration of intrinsic defects of this material. Optical absorption, ESR, photoluminescence, radioluminescence, and thermoluminescence are the main techniques used. The ionizing radiation induces formation of V centres. During the work its characteristics (structure, thermal stability, absorption spectra, etc.) has been studied. The thermoluminescence spectra allowed the discovery of several charge release processes between 85 and 650 K, all of them associated to electron release. The V-centres and several impurities (Cr, Mn,...) appear as recombination centres. The obtained data show that the kinetic of these charge release processes is regulated by the presence of a point defect with a very high concentration. This defect is an electron trap and its structure is an Al ion in a lattice site of tetrahedral symmetry. (Author)

Gelatin modified lipid nanoparticles for anti- viral drug delivery.

Science.gov (United States)

K S, Joshy; S, Snigdha; Kalarikkal, Nandakumar; Pothen, Laly A; Thomas, Sabu

2017-10-01

The major challenges to clinical application of zidovudine are its moderate aqueous solubility and relative short half-life and serious side effects due to frequent administrations. We investigated the preparation of zidovudine-loaded nanoparticles based on lipids which were further modified with the polymer gelatin. Formulation and stability of the modified nanoparticles were analysed from the physico-chemical characterizations. The interactions of nanoparticles with blood components were tested by haemolysis and aggregation studies. The drug content and entrapment efficiencies were assessed by UV analysis. The effect of nanoparticles on protein adsorption was assessed by native polyacrylamide gel electrophoresis (PAGE). In vitro release studies showed a sustained release profile of zidovudine. In vitro cytotoxicity and cellular uptake of the zidovudine-loaded nanoparticles were performed in MCF-7 and neuro 2a brain cells. The enhanced cellular internalization of drug loaded modified nanoparticles in both the cell lines were revealed by fluorescence microscopy. Hence the present study focuses on the feasibility of zidovudine-loaded polymer modified lipid nanoparticles as carriers for safe and efficient HIV/AIDS therapy. Copyright © 2017 Elsevier B.V. All rights reserved.

Understanding Drug Release Data through Thermodynamic Analysis.

Science.gov (United States)

Freire, Marjorie Caroline Liberato Cavalcanti; Alexandrino, Francisco; Marcelino, Henrique Rodrigues; Picciani, Paulo Henrique de Souza; Silva, Kattya Gyselle de Holanda E; Genre, Julieta; Oliveira, Anselmo Gomes de; Egito, Eryvaldo Sócrates Tabosa do

2017-06-13

Understanding the factors that can modify the drug release profile of a drug from a Drug-Delivery-System (DDS) is a mandatory step to determine the effectiveness of new therapies. The aim of this study was to assess the Amphotericin-B (AmB) kinetic release profiles from polymeric systems with different compositions and geometries and to correlate these profiles with the thermodynamic parameters through mathematical modeling. Film casting and electrospinning techniques were used to compare behavior of films and fibers, respectively. Release profiles from the DDSs were performed, and the mathematical modeling of the data was carried out. Activation energy, enthalpy, entropy and Gibbs free energy of the drug release process were determined. AmB release profiles showed that the relationship to overcome the enthalpic barrier was PVA-fiber > PVA-film > PLA-fiber > PLA-film. Drug release kinetics from the fibers and the films were better fitted on the Peppas-Sahlin and Higuchi models, respectively. The thermodynamic parameters corroborate these findings, revealing that the AmB release from the evaluated systems was an endothermic and non-spontaneous process. Thermodynamic parameters can be used to explain the drug kinetic release profiles. Such an approach is of utmost importance for DDS containing insoluble compounds, such as AmB, which is associated with an erratic bioavailability.

Understanding Drug Release Data through Thermodynamic Analysis

Science.gov (United States)

Freire, Marjorie Caroline Liberato Cavalcanti; Alexandrino, Francisco; Marcelino, Henrique Rodrigues; Picciani, Paulo Henrique de Souza; Silva, Kattya Gyselle de Holanda e; Genre, Julieta; de Oliveira, Anselmo Gomes; do Egito, Eryvaldo Sócrates Tabosa

2017-01-01

Understanding the factors that can modify the drug release profile of a drug from a Drug-Delivery-System (DDS) is a mandatory step to determine the effectiveness of new therapies. The aim of this study was to assess the Amphotericin-B (AmB) kinetic release profiles from polymeric systems with different compositions and geometries and to correlate these profiles with the thermodynamic parameters through mathematical modeling. Film casting and electrospinning techniques were used to compare behavior of films and fibers, respectively. Release profiles from the DDSs were performed, and the mathematical modeling of the data was carried out. Activation energy, enthalpy, entropy and Gibbs free energy of the drug release process were determined. AmB release profiles showed that the relationship to overcome the enthalpic barrier was PVA-fiber > PVA-film > PLA-fiber > PLA-film. Drug release kinetics from the fibers and the films were better fitted on the Peppas–Sahlin and Higuchi models, respectively. The thermodynamic parameters corroborate these findings, revealing that the AmB release from the evaluated systems was an endothermic and non-spontaneous process. Thermodynamic parameters can be used to explain the drug kinetic release profiles. Such an approach is of utmost importance for DDS containing insoluble compounds, such as AmB, which is associated with an erratic bioavailability. PMID:28773009

Thermodynamic modeling of hydrogen storage capacity in Mg-Na alloys.

Science.gov (United States)

Abdessameud, S; Mezbahul-Islam, M; Medraj, M

2014-01-01

Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems.

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.

[Effect of the interaction of microorganisms and iron oxides on arsenic releasing into groundwater in Chinese Loess].

Science.gov (United States)

Xie, Yun-Yun; Chen, Tian-Hu; Zhou, Yue-Fei; Xie, Qiao-Qin

2013-10-01

A large part of groundwater in the Chinese Loess Plateau area is characterized by high arsenic concentration. Anaerobic bacteria have been considered to play key roles in promoting arsenic releasing from loess to groundwater. However, this hypothesis remains unconfirmed. Based on modeling experiments, this study investigated the speciation of arsenic in loess, and then determined the release rates and quantities of arsenic with the mediation of anaerobic bacteria. The results showed that arsenic contents in loess were between 23 mg.kg-1 and 30 mg.kg-1. No obvious arsenic content difference among loess samples was observed. The ratios for specific adsorbed, iron oxides co-precipitated and silicate co-precipitated arsenic were 37.76% , 36. 15% and 25. 69% , respectively. Indigenous microorganisms, dissimilatory iron reducing bacteria (DIRB) and sulfate reducing bacteria (SRB) could all promote the release of arsenic from loess. Organic matters highly affected the release rates. More than 100 mg.L-1 sodium lactate was required for all bacterial experiments to facilitate obvious arsenic release. Considering the redox condition in loess, the contribution of SRB to arsenic release in loess area was less feasible than that of DIRB and indigenous microorganisms.

Dehydriding and re-hydriding properties of high-energy ball milled LiBH{sub 4}+MgH{sub 2} mixtures

Energy Technology Data Exchange (ETDEWEB)

Crosby, Kyle; Shaw, Leon L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, 97 North Eagleville Road, U-3136, Storrs, CT 06269 (United States)

2010-07-15

Here we report the first investigation of the dehydriding and re-hydriding properties of 2LiBH{sub 4} + MgH{sub 2} mixtures in the solid state. Such a study is made possible by high-energy ball milling of 2LiBH{sub 4}+MgH{sub 2} mixtures at liquid nitrogen temperature with the addition of graphite. The 2LiBH{sub 4}+MgH{sub 2} mixture ball milled under this condition exhibits a 5-fold increase in the released hydrogen at 265 C when compared with ineffectively ball milled counterparts. Furthermore, both LiBH{sub 4} and MgH{sub 2} contribute to hydrogen release in the solid state. The isothermal dehydriding/re-hydriding cycles at 265 C reveal that re-hydriding is dominated by re-hydriding of Mg. These unusual phenomena are explained based on the formation of nanocrystalline and amorphous phases, the increased defect concentration in crystalline compounds, and possible catalytic effects of Mg,MgH{sub 2} and LiBH{sub 4} on their dehydriding and re-hydriding properties. (author)

Prevalence of gastroduodenal ulcers/erosions in patients taking low-dose aspirin with either 15 mg/day of lansoprazole or 40 mg/day of famotidine: the OITA-GF study 2.

Science.gov (United States)

Tamura, Akira; Murakami, Kazunari; Kadota, Junichi

2013-03-26

The preventive effects of histamine 2 receptor antagonists vs. proton pump inhibitors on low-dose aspirin (LDA)-related gastroduodenal mucosal injury have not been fully investigated. We conducted a cross-sectional study to compare the prevalence of gastroduodenal ulcers or erosions in patients taking LDA with either 40 mg/day of famotidine or 15 mg/day of lansoprazole for at least three months. Of 84 eligible patients, two taking 40 mg/day of famotidine and four taking 15 mg/day of lansoprazole refused to undergo upper gastrointestinal endoscopy. Ultimately, we performed upper gastrointestinal endoscopy in 78 patients taking either 40 mg/day of famotidine (group F, n = 31) or 15 mg/day of lansoprazole (group L, n = 47). The prevalence of gastroduodenal ulcers or erosions and the magnitude of gastric mucosal injury evaluated using modified Lanza scores were compared between the two groups. No patients in either group had gastroduodenal ulcers. Gastroduodenal erosions were more prevalent in group F than in group L (48.4% vs. 17.0%, p = 0.005). The modified Lanza scores (mean ± SD) were significantly higher in group F than in group L (0.9 ± 1.3 vs. 0.3 ± 0.7, p = 0.007). A multivariate logistic regression analysis showed that the use of lansoprazole was negatively associated with gastroduodenal erosions. This study suggests that 15 mg/day of lansoprazole may be more effective in preventing the development of LDA-related gastroduodenal erosions than 40 mg/day of famotidine. The preventive effects of these two regimens on the development of LDA-related gastroduodenal ulcers require further investigation.

Effect of sustained-release isosorbide dinitrate on post-prandial gastric emptying and gastroduodenal motility in healthy humans

DEFF Research Database (Denmark)

Madsen, Jan Lysgård; Rasmussen, S L; Linnet, J

2004-01-01

and gastroduodenal motility after a meal. Eleven healthy volunteers participated in a double-blind, placebo-controlled, cross-over study. Each subject ingested 40 mg isosorbide dinitrate orally as a sustained-release formulation or oral placebo, in random order. Gastric emptying and gastroduodenal motility were...... consecutive 15-min periods. A 40 mg single dose of sustained-released isosorbide dinitrate does not seem to alter gastric emptying or gastroduodenal motility after a meal.......Nitric oxide (NO) is an inhibitory neurotransmitter released by non-adrenergic and non-cholinergic neurons that innervate the smooth muscles of the gastrointestinal tract. We examined whether NO, derived from a sustained-release preparation of isosorbide dinitrate, influenced gastric emptying...

Control of ATP hydrolysis by ADP bound at the catalytic site of chloroplast ATP synthase as related to protonmotive force and Mg2+

International Nuclear Information System (INIS)

Du, Z.; Boyer, P.D.

1989-01-01

The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. The data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg 2+ with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg 2+ is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg 2+ released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg 2+ the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg 2+ and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg 2+ . The replacement of [ 3 H]ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg 2+ and ADP bound at one catalytic site without P i block catalysis by all three enzyme sites. The inhibited form induced by Mg 2+ and ADP may occur only under laboratory conditions and not have an in vivo role

Comparative assessment of in vitro release kinetics of calcitonin polypeptide from biodegradable microspheres.

Science.gov (United States)

Prabhu, Sunil; Sullivan, Jennifer L; Betageri, Guru V

2002-01-01

The objective of our study was to compare the in vitro release kinetics of a sustained-release injectable microsphere formulation of the polypeptide drug, calcitonin (CT), to optimize the characteristics of drug release from poly-(lactide-co-glycolide) (PLGA) copolymer biodegradable microspheres. A modified solvent evaporation and double emulsion technique was used to prepare the microspheres. Release kinetic studies were carried out in silanized tubes and dialysis bags, whereby microspheres were suspended and incubated in phosphate buffered saline, sampled at fixed intervals, and analyzed for drug content using a modified Lowry protein assay procedure. An initial burst was observed whereby about 50% of the total dose of the drug was released from the microspheres within 24 hr and 75% within 3 days. This was followed by a period of slow release over a period of 3 weeks in which another 10-15% of drug was released. Drug release from the dialysis bags was more gradual, and 50% CT was released only after 4 days and 75% after 12 days of release. Scanning electron micrographs revealed spherical particles with channel-like structures and a porous surface after being suspended in an aqueous solution for 5 days. Differential scanning calorimetric studies revealed that CT was present as a mix of amorphous and crystalline forms within the microspheres. Overall, these studies demonstrated that sustained release of CT from PLGA microspheres over a 3-week period is feasible and that release of drug from dialysis bags was more predictable than from tubes.

SHAKER Version 0.0/5 Pre-release Notes

CERN Document Server

CERN. Geneva

1993-01-01

SHAKER V0.0/5 is a pre-release of a simple cocktail central rapidity phase space event generator developed for the simulation of LHC Heavy Ion events. A modified version of JETSET 7.3 (the / LUJETS / common has been enlarged to 50000 particles and the LUEDIT routine has been modified to rearrange the particle weights vectors when called with MEDIT=1) is used to manage the events. All event information is included in / LUJETS / according to Lund conventions [1].

Polymers having slow release function and their applications

International Nuclear Information System (INIS)

Kaetsu, Isao; Yamada, Akio.

1982-01-01

The research of giving slow releasing property to drugs by compounding them with suitable matrices and forming has been carried out actively in order to minimize the adverse effect, to reduce the frequency of administration and to improve the bioavailability of such drugs. The slow release function of drugs may be acquired by the copolymerization with synthetic and natural polymers. Drugs are mixed with monomers, and the mixture is polymerized by means of heat, light or radiation (gamma ray or electron beam). Various physical and chemical factors influencing on the rate of release are shown. The compound capsules of drugs and polymers may be used for chemotherapy, enzyme and hormone therapy, immunotherapy, artificial organs, medical and pharmaceutical applications in the form of suppositary, and administration by mucous membrane, subcutaneous and intra-fascia contact or burying. Mytomycin (MMC) of 1.6 mg/kg (LD 50 of i.v. injection) or 3.2 mg/kg (LD 50 x 2) was implanted in the abdomen of dogs. The release of MMC from the implanted capsules was relatively localized to the vicinity of implantation. More hydrophilic polymer (39 % water retention, for example, hydroxyethylmetacrylate polymer) gave more death (toxicity) cases than less hydrophilic one (2 % water retention, for example, diethylglycoldimetacrylate polymer) in the mice with Ehrlich ascites cancer cells, 5 x 10 6 cells/0.2 ml. Because of the nature of locally limited release of the drug, the capsules of anti-cancer drugs, analgesics, antibiotics, hormone, etc. should be delivered to disease foci by means of a fiber scope technique, or intravascular microcapsules. (Yamashita, S.)

Preparation of Mg(OH)_2 hybrid pigment by direct precipitation and graft onto cellulose fiber via surface-initiated atom transfer radical polymerization

International Nuclear Information System (INIS)

Wang, Xiao; Zhang, Yue; Lv, Lihua; Cui, Yongzhu; Wei, Chunyan; Pang, Guibing

2016-01-01

Graphical abstract: - Highlights: • Adsorbed anionic dye molecules are conducive to preferential growth of (0 0 1) plane of Mg(OH)_2 crystal for Mg(OH)_2 pigments. • Uniform coverage of nanosized Mg(OH)_2 pigments on fiber surface is achieved via surface-initiated ATRP. • About 4 wt% of Mg(OH)_2 pigment on fiber surface shortens nearly half of burning time of cellulose. - Abstract: Mg(OH)_2 flame retardant hybrid pigment is synthesized through simultaneous solution precipitation and adsorption of anionic dyes (C.I. Acid Red 6). The Mg(OH)_2 hybrid pigment bearing vinyl groups after surface silane modification is immobilized onto the surface of bromo end-functional cellulose fiber by atom transfer radical polymerization (ATRP). The morphology and structure of Mg(OH)_2 pigments and cellulose fibers grafted with modified pigments are characterized. The thermal properties, flammability and color fastness of cellulose fibers grafted with modified pigments are measured. The results reveal that anionic dye molecules are adsorbed onto Mg(OH)_2 crystals and affect the formation of lamella-like Mg(OH)_2 crystals. The cellulose fiber grafted with modified Mg(OH)_2 hybrid pigment absorbs about four times heat more than original cellulose fiber with about 4% immobilization ratio of pigment, which shortens nearly half of afterflame time and afterglow time.

Experimental investigation of the reactions {sup 25}Mg({alpha},n){sup 28}Si, {sup 26}Mg({alpha},n){sup 29}Si, {sup 18}O({alpha},n){sup 21}Ne and their impact on stellar nucleosynthesis

Energy Technology Data Exchange (ETDEWEB)

Falahat, Sascha

2010-06-10

In the present dissertation, the nuclear reactions {sup 25}Mg({alpha},n){sup 28}Si, {sup 26}Mg({alpha},n){sup 29}Si, {sup 18}O({alpha},n){sup 21}Ne are investigated in the astrophysically interesting energy region from E{sub {alpha}}=1000 keV to E{sub {alpha}}=2450 keV. The experiments were performed at the Nuclear Structure Laboratory of the University of Notre Dame (USA) with the Van-de-Graaff accelerator KN. Solid state targets with evaporated magnesium or anodized oxygen were bombarded with {alpha}-particles and the released neutrons detected. For the detection of the released neutrons, computational simulations were used to construct a neutron detector based on {sup 3}He counters. Because of the strong occurrence of background reactions, different methods of data analysis were employed. Finally, the impact of the reactions {sup 25}Mg({alpha},n){sup 28}Si, {sup 26}Mg({alpha},n){sup 29}Si, {sup 18}O({alpha},n){sup 21}Ne on stellar nucleosynthesis is investigated by means of network calculations. (orig.)

Nitric Oxide-Releasing Silica Nanoparticle-Doped Polyurethane Electrospun Fibers

Science.gov (United States)

Koh, Ahyeon; Carpenter, Alexis W.; Slomberg, Danielle L.; Schoenfisch, Mark H.

2013-01-01

Electrospun polyurethane fibers doped with nitric oxide (NO)-releasing silica particles are presented as novel macromolecular scaffolds with prolonged NO-release and high porosity. Fiber diameter (119–614 nm) and mechanical strength (1.7–34.5 MPa of modulus) were varied by altering polyurethane type and concentration, as well as the NO-releasing particle composition, size, and concentration. The resulting NO-releasing electrospun nanofibers exhibited ~83% porosity with flexible plastic or elastomeric behavior. The use of N-diazeniumdiolate- or S-nitrosothiol-modified particles yielded scaffolds exhibiting a wide range of NO release totals and durations (7.5 nmol mg−1–0.12 μmol mg−1 and 7 h to 2 weeks, respectively). The application of NO-releasing porous materials as coating for subcutaneous implants may improve tissue biocompatibility by mitigating the foreign body response and promoting cell integration. PMID:23915047

Fluoride release, recharge and flexural properties of polymethylmethacrylate containing fluoridated glass fillers.

Science.gov (United States)

Al-Bakri, I A; Swain, M V; Naoum, S J; Al-Omari, W M; Martin, E; Ellakwa, A

2014-06-01

The purpose of this study was to investigate the effect of fluoridated glass fillers on fluoride release, recharge and the flexural properties of modified polymethylmethacrylate (PMMA). Specimens of PMMA denture base material with various loading of fluoridated glass fillers (0%, 1%, 2.5%, 5% and 10% by weight) were prepared. Flexural properties were evaluated on rectangular specimens (n = 10) aged in deionized water after 24 hours, 1 and 3 months. Disc specimens (n = 10) were aged for 43 days in deionized water and lactic acid (pH 4.0) and fluoride release was measured at numerous intervals. After ageing, specimens were recharged and fluoride re-release was recorded at 1, 3 and 7 days after recharge. Samples containing 2.5%, 5% and 10% glass fillers showed significantly (p glass fillers specimens. All experimental specimens exhibited fluoride release in both media. The flexural strength of specimens decreased in proportion to the percentage filler inclusion with the modulus of elasticity values remaining within ISO Standard 1567. The modified PMMA with fluoridated glass fillers has the ability to release and re-release fluoride ion. Flexural strength decreased as glass filler uploading increased. © 2014 Australian Dental Association.

Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

Energy Technology Data Exchange (ETDEWEB)

Jiang, Huixin; Kobayashi, Takaomi, E-mail: takaomi@nagaokaut.ac.jp

2017-06-01

Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm{sup 3}) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm{sup 3} of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

Ultrasound stimulated release of gallic acid from chitin hydrogel matrix

International Nuclear Information System (INIS)

Jiang, Huixin; Kobayashi, Takaomi

2017-01-01

Ultrasound (US) stimulated drug release was examined in this study using a chitin hydrogel matrix loaded with gallic acid (GA), a drug used for wound healing and anticancer. Using phase inversion, GA-chitin hydrogels were prepared from chitin-dimethylacetamide (DMAc)/lithium chloride (LiCl) solution in the presence of GA, with 24 h exposure of the solution to water vapor. The GA release from the GA-chitin hydrogel was examined under different US powers of 0–30 W at 43 kHz. The effects of GA loading amounts in the hydrogels (0.54, 0.43, and 0.25 mg/cm 3 ) and chitin concentrations (0.1, 0.5, and 1 wt%) on the release behaviors were recorded under 43 kHz US exposure at 30 W. Results show that US accelerated the release efficiencies for all samples. Furthermore, the release efficiency increased concomitantly with increasing US power, GA loading amount, and decrease of the chitin concentration. The highest release rate of 0.74 μg/mL·min was obtained from 0.54 mg/cm 3 of GA-loaded hydrogel fabricated from a 0.1 wt% chitin mixture solution under 43 kHz US exposure at 30 W: nine times higher than that of the sample without US exposure. The hydrogel viscoelasticity demonstrated that the US irradiation rigidified the material. FT-IR showed that US can break the hydrogen bonds in the GA-chitin hydrogels. - Highlights: • Ultrasound (US) stimulated Gallic acid (GA) release from chitin hydrogel was studied. • The release efficiency of GA from chitin hydrogel increased nine times when irradiated by 43 kHz US compared with the sample without US. • Generalized 2D correlation and deconvolution study of FT-IR showed that US could promote the GA release by breaking hydrogen bonds.

Release behavior of drugs from various natural gums and polymers.

Science.gov (United States)

Singh, Anupama; Sharma, Pramod Kumar; Malviya, Rishabha

2011-01-01

Polymers are the high molecular weight compounds of natural or synthetic origin, widely used in drug delivery of formulations. These polymers are further classified as hydrophilic or hydrophobic in nature. Depending upon this characteristic, polymers exhibit different release behavior in different media. This property plays an important role in the selection of polymers for controlled, sustained or immediate release formulations. The review highlights the literatures related to the research made on several polymers regarding the release kinetics which made them a novel approach for modifying the action of the particular formulation.

Ionizing radiation effects in MgAl2O4

International Nuclear Information System (INIS)

Ibarra Sanchez, A.

1990-01-01

The effect of ionizing radiation in MgAl2O4 has been studied, paying special interest to the influence of the high concentration of intrinsic dsefects of this material. Optical absorption, ESR, photoluminiscence, radioluminiscence, and thermoluminiscence are the main techniques used. The ionizing radiation induces to formation of V centres. During the work its characteristics (structure, thermal stability, absorption spectra, etc.) has been studied. The thermoluminiscence spectra allowed the discovery of several charge release processes between 85 and 650 K, all of them associated to electron release. The V-centres and several impurities (Cr, Mn,...) appear as recombination centres. The obtained data show that the kinetic of these charge release processes is regulated by the presence of a point defect with a very high concentration. This defect is an electron trap and its structure is an Al ion in a lattice site of tetraedral symmetry. (Author)

Self-assembled nanoparticles of modified-chitosan conjugates for the sustained release of dl-α-tocopherol

DEFF Research Database (Denmark)

Quinones, Javier Perez; Gothelf, Kurt Vesterager; Kjems, Jørgen

2013-01-01

Synthetic O6-succinylated chitosan and commercial glycol chitosan were covalently linked to dl-α-tocopheryl monoesters for controlled release of vitamin E. These conjugates formed self-assembled nanoparticles in aqueous solution with 254–496 nm mean diameters and dl-α-tocopherol contents between 27...... and 39% (w/w). The particles appeared as 40–75 nm almost spherical nanoparticles when studied by scanning and transmission electron microscopy upon drying. Drug linking to chitosan matrix was confirmed by FTIR spectroscopy and proton NMR. Conjugates were also characterized by differential scanning...... calorimetry and wide-angle X-ray diffraction. In vitro tocopherol release studies performed in water at acid pH indicated a drug release dependence on drug content, hydrated particle sizes and employed chitosan derivative. Almost constant release rates were observed the first 7 h. The obtained nanoparticles...

In vitro and in vivo corrosion, mechanical properties and biocompatibility evaluation of MgF2-coated Mg-Zn-Zr alloy as cancellous screws.

Science.gov (United States)

Li, Zhen; Shizhao, Sun; Chen, Minfang; Fahlman, Bradley Dean; Debao Liu; Bi, Hongwei

2017-06-01

Magnesium (Mg) and its alloys as biodegradable materials have received much attention in the orthopedics applications; however, the corrosion behavior of these metals in vivo remains challenging. In this work, a dense and nanoscale magnesium fluoride (MgF 2 ) coating was deposited on the surface of Mg-Zn-Zr (MZZ) alloy cancellous screw. The MZZ cancellous screw with MgF 2 coating maintained an integrated shape and high yield tensile stress after 30days immersion in SBF, comparing with the bare screw. Hydrogen releasing rate of the MZZ samples was suppressed at a lower level at the initial stage, which is in favour of the adhesion of the cells. And in vivo experiments indicated that MgF 2 -coated MZZ screws presented advantages in cytocompatibility, osteoconductivity and osteogenesis of cancellous bone in rabbits. Corrosion rate in vivo perfusion environment increased very slowly with time in long-term study, which was an opposite trend in vitro static immersion test. Moreover, maximum corrosion rate (CR max ), a critical calculation method of corrosion rate was introduced to predict fracture regions of the sample. The MZZ alloy with MgF 2 coating possesses a great potential for clinical applications for internal fracture fixation repair. Copyright © 2017 Elsevier B.V. All rights reserved.

Quality evaluation of extemporaneous delayed-release liquid formulations of lansoprazole.

Science.gov (United States)

Melkoumov, Alexandre; Soukrati, Amina; Elkin, Igor; Forest, Jean-Marc; Hildgen, Patrice; Leclair, Grégoire

2011-11-01

The quality attributes of extemporaneous delayed-release liquid formulations of lansoprazole for oral administration were evaluated. A novel liquid formulation (3 mg/mL) of Prevacid FasTab in an Ora-Blend vehicle was prepared and compared with the Prevacid FasTab 30 mg and Prevacid-sodium bicarbonate 1 M formulation (3 mg/mL). The latter formulation was combined with hydrochloric acid 0.1 N, and the remaining lansoprazole content was assayed by high-performance liquid chromatography (HPLC). A batch of delayed-release liquid formulation was prepared to evaluate content uniformity. For content assay, three samples were prepared for each evaluated condition and each sample was analyzed in triplicate by HPLC. The lansoprazole in the sodium bicarbonate formulation was extensively degraded by quantities of hydrochloric acid 0.1 N in excess of 100 mL. Storage time and temperature had a significant effect on lansoprazole stability in the Ora-Blend formulation. The drug remained stable for seven days when the formulation was stored at 4.5-5.5 °C, but storage at 21-22 °C or the reduction of pH with citric acid accelerated lansoprazole degradation. The amount of lansoprazole released from the Ora-Blend formulation during the buffer stage of the dissolution test decreased with increases in formulation storage time, in formulation storage temperature, and in the amount of lansoprazole released and degraded during the acid stage of the test. An extemporaneous formulation consisting of lansoprazole microgranules in Ora-Blend maintained acceptable quality attributes when stored for three days at 4.5-5.5 °C.

Saiboku-to, a Kampo herbal medicine, inhibits LTC4 release from eosinophils

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Koichi Hirai

1998-01-01

Full Text Available Saiboku-to (TJ-96, a traditional Kampo herbal formation, has been used in the treatment of bronchial asthma in Japan as an anti-allergy herbal medicine. We investigated the effect of TJ-96 on leukotriene (LTC4 release from eosinophils and basophils isolated from healthy volunteers. Pre-incubation of eosinophils with TJ-96 inhibited ionophore- or formyl-methionyl-leucyl-phenylalanine (FMLP-induced LTC4 generation by eosinophils in a dose-dependent fashion. The TJ-96 was more potent in the release by ionophore (IC50 = 60 mg/mL than the release induced by FMLP (IC50 = 300 mg/mL. Maximal inhibition was observed when eosinophils were pretreated with TJ-96 for 5 min. Although TJ-96 at high concentrations inhibited IgE-mediated histamine release from human basophils, inhibition of IgE-mediated LTC4 release was not statistically significant. The potent inhibitory activity was found in the extract of Glycyrrhiza root, one of the herbal components of TJ-96, but the inhibitory effects were not due to either glycyrrhizin or liquiritin, the main elements of the Glycyrrhiza root. These results raise the possibility that the clinical efficacy of TJ-96 is derived, at least in part, from its potent inhibitory effect on LTC4 release from eosinophils.

A Palladium-Tin Modified Microband Electrode Array for Nitrate Determination

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Yexiang Fu

2015-09-01

Full Text Available A microband electrode array modified with palladium-tin bimetallic composite has been developed for nitrate determination. The microband electrode array was fabricated by Micro Electro-Mechanical System (MEMS technique. Palladium and tin were electrodeposited successively on the electrode, forming a double-layer structure. The effect of the Pd-Sn composite was investigated and its enhancement of catalytic activity and lifetime was revealed. The Pd-Sn modified electrode showed good linearity (R2 = 0.998 from 1 mg/L to 20 mg/L for nitrate determination with a sensitivity of 398 μA/(mg∙L−1∙cm2. The electrode exhibited a satisfying analytical performance after 60 days of storage, indicating a long lifetime. Good repeatability was also displayed by the Pd-Sn modified electrodes. The results provided an option for nitrate determination in water.

Atorvastatin 10 mg plus ezetimibe 10mg compared with atorvastatin 20 mg: impact on the lipid profile in Japanese patients with abnormal glucose tolerance and coronary artery disease.

Science.gov (United States)

Uemura, Yusuke; Watarai, Masato; Ishii, Hideki; Koyasu, Masayoshi; Takemoto, Kenji; Yoshikawa, Daiji; Shibata, Rei; Matsubara, Tatsuaki; Murohara, Toyoaki

2012-01-01

Oxidized low-density lipoprotein (LDL) cholesterol is a sensitive lipid marker for predicting atherosclerosis. Ezetimibe and statins are reported to decrease both LDL cholesterol and oxidized LDL cholesterol. This prospective randomized open-label crossover study compared combination therapy with atorvastatin plus ezetimibe versus high-dose atorvastatin monotherapy. Changes in serum lipids, including malondialdehyde-modified LDL (MDA-LDL) as a representative form of oxidized LDL cholesterol, and glucose metabolism were assessed. The subjects were 39 Japanese patients with coronary artery disease and type 2 diabetes or impaired glucose tolerance who were taking 10 mg/day of atorvastatin (30 men and 9 women with a mean age of 67.8 years). They were randomized to a group that first received add-on ezetimibe (10 mg/day) or a group that first received atorvastatin monotherapy at a higher dose of 20 mg/day. Both treatments were given for 12 weeks each in a crossover fashion. Add-on ezetimibe significantly decreased MDA-LDL (109.0 ± 31.9 mg/dl to 87.7 ± 29.4 mg/dl, p=0.0009), while up-titration of atorvastatin did not. The decrease with add-on ezetimibe was significantly greater than with up-titration of atorvastatin (p=0.0006). Total cholesterol and LDL cholesterol were significantly decreased by both treatments, but the percent reduction with add-on ezetimibe was significantly greater (pHigh-density lipoprotein cholesterol was significantly increased by both treatments and there was no significant difference between them. The apolipoprotein B/apolipoprotein A-I ratio and remnant-like particle cholesterol were only significantly decreased by add-on ezetimibe. Both treatments caused similar elevation of hemoglobin A(1c). In Japanese patients with type 2 diabetes or impaired glucose tolerance and coronary artery disease, adding ezetimibe (10 mg/day) to atorvastatin (10 mg/day) significantly improved the lipid profile compared with atorvastatin monotherapy at 20 mg

Stereoselectivity of presynaptic autoreceptors modulating dopamine release

International Nuclear Information System (INIS)

Arbilla, S.; Langer, S.Z.

1981-01-01

The effects of the (R)- and (S)-enantiomers of sulpiride and butaclamol were studied on the spontaneous and field stimulation-evoked release of total radioactivity from slices of rabbit caudate nucleus prelabelled with [ 3 H]dopamine. (S)-Sulpiride in concentrations ranging from 0.01-1μM enhanced the electrically evoked release of [ 3 H]dopamine while (R)-sulpiride was 10 times less potent than (S)-sulpiride. Exposure to (S)-butaclamol (0.1-1 μM) but not to (R)-butaclamol (0.1-10μM) enhanced the field-stimulated release of [ 3 H]dopamine. The facilitatory effects of (S)- and (R)-sulpiride and (S)-butaclamol on the stimulated release of the labelled neurotransmitter were observed under conditions in which these drugs did not modify the spontaneous outflow of radioactivity. Only the active enantiomers of sulpiride and butaclamol antagonized the inhibition by apomorphine (1μM) of the stimulated release of [ 3 H]dopamine. Our results indicate that the presynaptic inhibitory dopamine autoreceptors modulating the stimulation-evoked release of [ 3 H]dopamine in the caudate nucleus are, like the classical postsynaptic dopamine receptors, chemically stereoselective. (Auth.)

BTEX and MTBE adsorption onto raw and thermally modified diatomite.

Science.gov (United States)

Aivalioti, Maria; Vamvasakis, Ioannis; Gidarakos, Evangelos

2010-06-15

The removal of BTEX (benzene, toluene, ethyl-benzene and xylenes) and MTBE (methyl tertiary butyl ether) from aqueous solution by raw (D(R)) and thermally modified diatomite at 550, 750 and 950 degrees C (D(550), D(750) and D(950) respectively) was studied. Physical characteristics of both raw and modified diatomite such as specific surface, pore volume distribution, porosity and pH(solution) were determined, indicating important structural changes in the modified diatomite, due to exposure to high temperatures. Both adsorption kinetic and isotherm experiments were carried out. The kinetics data proved a closer fit to the pseudo-second order model. Maximum values for the rate constant, k(2), were obtained for MTBE and benzene (48.9326 and 18.0996 g mg(-1)h(-1), respectively) in sample D(550). The isotherm data proved to fit the Freundlich model more closely, which produced values of the isotherm constant 1/n higher than one, indicating unfavorable adsorption. The highest adsorption capacity, calculated through the values of the isotherm constant k(F), was obtained for MTBE (48.42 mg kg(-1) (mg/L)(n)) in sample D(950). Copyright 2010 Elsevier B.V. All rights reserved.

Sodium lauryl sulfate impedes drug release from zinc-crosslinked alginate beads: switching from enteric coating release into biphasic profiles.

Science.gov (United States)

Taha, Mutasem O; Nasser, Wissam; Ardakani, Adel; Alkhatib, Hatim S

2008-02-28

The aim of this research is to investigate the effects of sodium lauryl sulfate (SLS) on ionotropically cross-linked alginate beads. Different levels of SLS were mixed with sodium alginate and chlorpheniramine maleate (as loaded model drug). The resulting viscous solutions were dropped onto aqueous solutions of zinc or calcium ions for ionotropic curing. The generated beads were assessed by their drug releasing profiles, infrared and differential scanning colorimetery (DSC) traits. SLS was found to exert profound concentration-dependent impacts on the characteristics of zinc-crosslinked alginate beads such that moderate modifications in the levels of SLS switched drug release from enteric coating-like behavior to a biphasic release modifiable to sustained-release by the addition of minute amounts of xanthan gum. Calcium cross-linking failed to reproduce the same behavior, probably due to the mainly ionic nature of calcium-carboxylate bonds compared to the coordinate character of their zinc-carboxylate counterparts. Apparently, moderate levels of SLS repel water penetration into the beads, and therefore minimize chlorpheniramine release. However, higher SLS levels seem to discourage polymeric cross-linking and therefore allow biphasic drug release.

Control of ATP hydrolysis by ADP bound at the catalytic site of chloroplast ATP synthase as related to protonmotive force and Mg sup 2+

Energy Technology Data Exchange (ETDEWEB)

Du, Z.; Boyer, P.D. (Univ. of California, Los Angeles (USA))

1989-01-24

The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. The data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg{sup 2+} with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg{sup 2+} is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg{sup 2+} released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg{sup 2+} the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg{sup 2+} and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg{sup 2+}. The replacement of ({sup 3}H)ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg{sup 2+} and ADP bound at one catalytic site without P{sub i} block catalysis by all three enzyme sites. The inhibited form induced by Mg{sup 2+} and ADP may occur only under laboratory conditions and not have an in vivo role.

MgO-modified mesoporous silicas impregnated by potassium carbonate for carbon dioxide adsorption

Czech Academy of Sciences Publication Activity Database

Zukal, Arnošt; Pastva, Jakub; Čejka, Jiří

2013-01-01

Roč. 167, FEB 2013 (2013), s. 44-50 ISSN 1387-1811 R&D Projects: GA ČR GA203/08/0604 Institutional support: RVO:61388955 Keywords : mesoporous adsorbents * SBA-15 silica * introducing of MgO and K2CO3 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.209, year: 2013

Preparation and evaluation of tamsulosin hydrochloride sustained-release pellets modified by two-layered membrane techniques

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Jingmin Wang

2015-02-01

Full Text Available The aim of the present study was to develop tamsulosin hydrochloride sustained-release pellets using two-layered membrane techniques. Centrifugal granulator and fluidized-bed coater were employed to prepare drug-loaded pellets and to employ two-layered membrane coating respectively. The prepared pellets were evaluated for physicochemical characterization, subjected to differential scanning calorimetry (DSC and in vitro release of different pH. Different release models and scanning electron microscopy (SEM were utilized to analyze the release mechanism of Harnual® and home-made pellets. By comparing the dissolution profiles, the ratio and coating weight gain of Eudragit® NE30D and Eudragit® L30D55 which constitute the inside membrane were identified as 18:1 and 10%–11%. The coating amount of outside membrane containing Eudragit® L30D55 was determined to be 0.8%. The similarity factors (f2 of home-made capsule and commercially available product (Harnual® were above 50 in different dissolution media. DSC studies confirmed that drug and excipients had good compatibility and SEM photographs showed the similarities and differences of coating surface between Harnual® and self-made pellets before and after dissolution. According to Ritger-Peppas model, the two dosage form had different release mechanism.

Understanding Drug Release Data through Thermodynamic Analysis

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Marjorie Caroline Liberato Cavalcanti Freire

2017-06-01

Full Text Available Understanding the factors that can modify the drug release profile of a drug from a Drug-Delivery-System (DDS is a mandatory step to determine the effectiveness of new therapies. The aim of this study was to assess the Amphotericin-B (AmB kinetic release profiles from polymeric systems with different compositions and geometries and to correlate these profiles with the thermodynamic parameters through mathematical modeling. Film casting and electrospinning techniques were used to compare behavior of films and fibers, respectively. Release profiles from the DDSs were performed, and the mathematical modeling of the data was carried out. Activation energy, enthalpy, entropy and Gibbs free energy of the drug release process were determined. AmB release profiles showed that the relationship to overcome the enthalpic barrier was PVA-fiber > PVA-film > PLA-fiber > PLA-film. Drug release kinetics from the fibers and the films were better fitted on the Peppas–Sahlin and Higuchi models, respectively. The thermodynamic parameters corroborate these findings, revealing that the AmB release from the evaluated systems was an endothermic and non-spontaneous process. Thermodynamic parameters can be used to explain the drug kinetic release profiles. Such an approach is of utmost importance for DDS containing insoluble compounds, such as AmB, which is associated with an erratic bioavailability.

New Promising Hydride Based on the Cu-Li-Mg System

Energy Technology Data Exchange (ETDEWEB)

Braga, M H; Acatrinei, A; Hartl, M; Vogel, S; Proffen, Th; Daemen, L, E-mail: mbraga@lanl.gov

2010-11-01

We investigated the ternary Cu-Li-Mg system, in particular the CuLi{sub x}Mg{sub 2-x} (x = 0.08) for hydrogen storage. Instead of crystallizing in an orthorhombic phase, as CuMg2, this phase presents a hexagonal structure very similar to that of NiMg{sub 2} and NiMg{sub 2}H{sub 0.3}. In this work we will discuss the structure of CuLi{sub x}Mg{sub 2-x} by the analysis of the neutron scattering data and first principles calculations. The first results for a hydride (deuteride) phase will also mentioned since preliminary studies at LANSCE showed that CuLi{sub x}Mg{sub 2-x} might absorb approximately 5.3 to 6 wt% of H at an equilibrium pressure of approximately 27 bar at 200 deg. C. If these results are confirmed in future work, this will mean that, not only CuLi{sub x}Mg{sub 2-x} absorbs a considerable amount of hydrogen (close to DOE's expectations for hydrogen storage materials), but also will probably release it at a temperature in the range of 50 to 150 deg. C, where applications are easier to develop. Hence it should be possible to use this alloy with fuel cells or in batteries. Another important observation is that cycling has a strong effect on the structure of the hydride.

Inclusion of cefalexin in SBA-15 mesoporus material and release property

International Nuclear Information System (INIS)

Zhai, Qing-Zhou

2012-01-01

SBA-15 (Santa Barbara Amorphous-15) is a high ordered mesoporous material. It has the advantages of a non-toxic property, good hydrothermal stability and thermal stability, etc. Inside inner surface a lot of silanols exist. Pore diameter size is uniform and pore size distribution is narrow. This structural feature makes SBA-15 have a higher loading drug amount and be able to effectively extend the drug release cycle. In this paper, polyethylene glycol-block-polypropylene glycol-block-polyethylene glycol was used as template and tetraethyl orthosilicate was used as silica source to prepare SBA-15 by hydrothermal synthesis method. Cefalexin was included in SBA-15 and the included cefalexin drug content was 158.72 mg/g. The composite materials were characterized by using chemical analysis, powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), infrared (IR) spectroscopy, and low temperature nitrogen adsorption–desorption. The results showed that cefalexin had been successfully included in host SBA-15 pore channels. Rational analyses of the release processes of cefalexin drug from the pores of SBA-15 to the simulated body fluid, simulated gastric juice and simulated intestinal fluid were made and sustained-release effects of the drug in complex system were studied. The results showed that in simulated body fluid within 1–5 h cefalexin was fast released and the cumulative release reached 50.00% at 5 h. In 15–20 h, the sustained release speed of cefalexin drug in the composite material decreased and the sustained-release cumulative amount reached 99.87% at 20 h. The release of cefalexin was basically complete. In simulated gastric fluid, composite material sustained-release ended at 4 h, the cumulative sustained release ratio reaching 26.10%. In simulated gastric fluid, the sustained-release was complete at 7 h, the cumulative sustained release ratio reaching 32.46%. The composite material of SBA-15 and cefalexin

Agrobacterium-mediated transformation of modified antifreeze protein gene in strawberry

Directory of Open Access Journals (Sweden)

Srisulak Dheeranupattana

2005-07-01

Full Text Available The optimum condition for shoot regeneration from leaf explants of strawberry cultivar Tiogar was investigated. It was found that the best regeneration condition was MS medium containing N6-Benzyladenine (BA and 2,4-Dichlorophenoxy acetic acid (2,4-D at concentrations of 1 mg.l-1 and 0.2 mg.l-1, respectively. Antibiotics sensitivity test found that shoot regeneration from leaf explant was inhibited more than 90% at the concentration of kanamycin (Km as low as 5 mg.l-1. The modified gene encoding antifreeze protein isoform HPLC 6 was successfully constructed using codons which were optimally expressed in the strawberry plant. The antifreeze protein genes, naturally in plasmid pSW1 and modified in plasmid BB, were transformed to strawberry leaf explants by Agrobacterium tumefaciens LBA 4404. The strawberry plants, transformed with both AFP genes, were able to root in MS media containing 50 mg.l-1 Km, while no roots grew from nontransformed plant in this condition. Polymerase chain reaction indicated that the transgenes were integrated in the genome of transformants.

Progesterone PLGA/mPEG-PLGA Hybrid Nanoparticle Sustained-Release System by Intramuscular Injection.

Science.gov (United States)

Xie, Bin; Liu, Yang; Guo, Yuting; Zhang, Enbo; Pu, Chenguang; He, Haibing; Yin, Tian; Tang, Xing

2018-02-14

To prepare sustained-release PLGA/mPEG-PLGA hybrid nanoparticles of progesterone (PRG), and evaluate the descending required administration dosage in vivo. PRG hybrid nanoparticles (PRG H-NPs) based on PLGA/mPEG-PLGA were compared with PRG nanoparticles (PRG-NPs) of pure PLGA as the matrix and PRG-oil solutions. Nanoparticles (NPs) were formed by the method of nanoemulsion, and the pharmacokinetics of the sustained-release PRG H-NPs in male Sprague dawley (SD) rats were investigated. The rats were randomly divided into four groups, each group received: single dose of PRG H-NPs (14.58 mg/kg, i.m.) and PRG-NPs (14.58 mg/kg, i.m.), repeated dosing for 7 days of PRG-oil (2.08 mg/kg, i.m.) solution (Oil-L) and a higher dosage of PRG-oil (6.24 mg/kg, i.m.) solution (Oil-H), respectively. In the pharmacokinetic test, the PRG H-NPs exhibited a comparatively good sustained-release effect against the PRG-NPs without mPEG-PLGA and PRG-oil solution. The pharmacokinetic parameters of the PRG H-NPs, PRG-NPs, Oil-L and Oil-H were AUC 0-t (ng·h·mL -1 ) 8762.1, 1546.1, 1914.5, and 12,138.9, t 1/2 (h)52.7, 44.1, 8.4 and 44.6 respectively. Owing to the modification of PEG, PRG H-NPs can act as safe delivery platforms for sustained-release of drugs with a lower dosage required.

TOXRISK, Toxic Gas Release Accident Analysis

International Nuclear Information System (INIS)

Bennett, D.E.; Chanin, D.I.; Shiver, A.W.

1993-01-01

1 - Description of program or function: TOXRISK is an interactive program developed to aid in the evaluation of nuclear power plant control room habitability in the event of a nearby toxic material release. The program uses a model which is consistent with the approach described in the NRC Regulatory Guide 1.78. Release of the gas is treated as an initial puff followed by a continuous plume. The relative proportions of these as well as the plume release rate are supplied by the user. Transport of the gas is modeled as a Gaussian distribution and occurs through the action of a constant velocity, constant direction wind. Great flexibility is afforded the user in specifying the release description, meteorological conditions, relative geometry of the accident and plant, and the plant ventilation system characteristics. Two types of simulation can be performed: multiple case (parametric) studies and probabilistic analyses. Upon execution, TOXRISK presents a menu, and the user chooses between the Data Base Manager, the Multiple Case program, and the Probabilistic Study Program. The Data Base Manager provides a convenient means of storing, retrieving, and modifying blocks of data required by the analysis programs. The Multiple Case program calculates resultant gas concentrations inside the control room and presents a summary of information that describes the event for each set of conditions given. Optimally, a time history profile of inside and outside concentrations can also be produced. The Probabilistic Study program provides a means for estimating the annual probability of operator incapacitation due to toxic gas accidents on surrounding transportation routes and storage sites. 2 - Method of solution: Dispersion or diffusion of the gas during transport is described by modified Pasquill-Gifford dispersion coefficients

Dosimetric Characteristics of a LKB:Cu,Mg Solid Thermoluminescence Detector

International Nuclear Information System (INIS)

Alajerami Yasser Saleh Mustafa; Hashim Suhairul; Ramli Ahmad Termizi; Saleh Muneer Aziz; Kadir Ahmad Bazlie Bin Abdul; Saripan, Mohd. Iqbal

2013-01-01

We present the main thermoluminescence characteristics of a newly borate glass dosimeter modified with lithium and potassium carbonate (LKB) and co-doped with CuO and MgO. An enhancement of about three times has been shown with the increment of 0.1mol% MgO as a co-dopant impurity. The effects of dose linearity, storage capacity, effective atomic number and energy dose response are studied. The proposed dosimeter shows a simple glow curve, good linearity up to 10 3 Gy, close effective atomic number and photon energy independence. The current results suggest using the proposed dosimeter in different dosimetric applications

Selective adsorption and release of cationic organic dye molecules on mesoporous borosilicates

International Nuclear Information System (INIS)

Paul, Manidipa; Pal, Nabanita; Bhaumik, Asim

2012-01-01

Mesoporous materials can play a pivotal role as a host material for delivery application to a specific part of a system. In this work we explore the selective adsorption and release of cationic organic dye molecules such as safranine T (ST) and malachite green (MG) on mesoporous borosilicate materials. The mesoporous silica SBA-15 and borosilicate materials (MBS) were prepared using non-ionic surfactant Pluronic P123 as template via evaporation induced self-assembly (EISA) method. After template removal the materials show high surface areas and in some cases ordered mesopores of dimensions ca. 6–7 nm. High surface area, mesoporosity and the presence of heteroatom (boron) help this mesoporous borosilicate material to adsorb high amount of cationic dye molecules at its surface from the respective aqueous solutions. Furthermore, the mesoporous borosilicate samples containing higher percentage adsorbed dyes show excellent release of ST or MG dye in simulated body fluid (SBF) solution at physiological pH = 7.4 and temperature 310 K. The adsorption and release efficiency of mesoporous borosilicate samples are compared with reference boron-free mesoporous pure silica material to understand the nature of adsorbate–adsorbent interaction at the surfaces. - Graphical abstract: Highly ordered 2D-hexagonal mesoporous borosilicate materials have been synthesized by using Pluronic P123 as template. The materials show very good adsorption and release of organic cationic dye molecules under physiological conditions. Highlights: ► Highly ordered 2D-hexagonal mesoporous borosilicate. ► Nonionic Pluoronic P123 templated mesoporous material. ► Adsorption of organic dyes at the mesopore surface. ► Controlled release of dyes under physiological pH and temperature. ► Release of safranine T (ST) and malachite green (MG) dyes in simulated body fluids.

Thermodynamic Modeling of Hydrogen Storage Capacity in Mg-Na Alloys

Science.gov (United States)

Abdessameud, S.; Mezbahul-Islam, M.; Medraj, M.

2014-01-01

Thermodynamic modeling of the H-Mg-Na system is performed for the first time in this work in order to understand the phase relationships in this system. A new thermodynamic description of the stable NaMgH3 hydride is performed and the thermodynamic models for the H-Mg, Mg-Na, and H-Na systems are reassessed using the modified quasichemical model for the liquid phase. The thermodynamic properties of the ternary system are estimated from the models of the binary systems and the ternary compound using CALPHAD technique. The constructed database is successfully used to reproduce the pressure-composition isotherms for MgH2 + 10 wt.% NaH mixtures. Also, the pressure-temperature equilibrium diagram and reaction paths for the same composition are predicted at different temperatures and pressures. Even though it is proved that H-Mg-Na does not meet the DOE hydrogen storage requirements for onboard applications, the best working temperatures and pressures to benefit from its full catalytic role are given. Also, the present database can be used for thermodynamic assessments of higher order systems. PMID:25383361

Modification of Sodium Release Using Porous Corn Starch and Lipoproteic Matrix.

Science.gov (United States)

Christina, Josephine; Lee, Youngsoo

2016-04-01

Excessive sodium consumption can result in hypertension, diabetes, heart diseases, stroke, and kidney diseases. Various chips and extruded snacks, where salt is mainly applied on the product surface, accounted for almost 56% of snacks retail sales in 2010. Hence, it is important to target sodium reduction for those snack products. Past studies had shown that modifying the rate-release mechanism of sodium is a promising strategy for sodium reduction in the food industry. Encapsulation of salt can be a possible technique to control sodium release rate. Porous corn starch (PCS), created by enzymatic treatment and spray drying and lipoproteic matrix, created by gelation and freeze drying, were evaluated as carriers for controlled sodium release targeting topically applied salts. Both carriers encapsulated salt and their in vitro sodium release profiles were measured using a conductivity meter. The sodium release profiles of PCS treated with different enzymatic reaction times were not significantly different. Protein content and fat content altered sodium release profile from the lipoproteic matrix. The SEM images of PCS showed that most of the salt crystals coated the starch instead of being encapsulated in the pores while the SEM images and computed tomography scan of lipoproteic matrix showed salt dispersed throughout the matrix. Hence, PCS was found to have limitations as a sodium carrier as it could not effectively encapsulate salt inside its pores. The lipoproteic matrix was found to have a potential as a sodium carrier as it could effectively encapsulate salt and modify the sodium release profile. © 2016 Institute of Food Technologists®

Multifunctional PEG modified DOX loaded mesoporous silica nanoparticle@CuS nanohybrids as photo-thermal agent and thermal-triggered drug release vehicle for hepatocellular carcinoma treatment

Science.gov (United States)

Wu, Lingjie; Wu, Ming; Zeng, Yongyi; Zhang, Da; Zheng, Aixian; Liu, Xiaolong; Liu, Jingfeng

2015-01-01

The combination of a multi-therapeutic mode with a controlled fashion is a key improvement in nanomedicine. Here, we synthesized polyethylene glycol (PEG)-modified doxorubicin (DOX)-loaded mesoporous silica nanoparticle (MSN) @CuS nanohybrids as efficient drug delivery carriers, combined with photothermal therapy and chemotherapy to enhance the therapeutic efficacy on hepatocellular carcinoma (HCC). The physical properties of the nanohybrids were characterized by transmission electron microscopy (TEM), N2 adsorption and desorption experiments and by the Vis-NIR absorption spectra. The results showed that the doxorubicin could be stored in the inner pores of mesoporous silica nanoparticles; the CuS nanoparticles, which are coated on the surface of a mesoporous silica nanoparticle, could serve as efficient photothermal therapy (PTT) agents; the loaded drug release could be easily triggered by NIR irradiation. The combination of the PTT treatment with controlled chemotherapy could further enhance the cancer ablation ability compared to any of the single approaches alone. Hence, the reported PEG-modified DOX-loaded mesoporous silica nanoparticle@CuS nanohybrids might be very promising therapeutic agents for HCC treatment.

Biodegradability engineering of biodegradable Mg alloys: Tailoring the electrochemical properties and microstructure of constituent phases

Science.gov (United States)

Cha, Pil-Ryung; Han, Hyung-Seop; Yang, Gui-Fu; Kim, Yu-Chan; Hong, Ki-Ha; Lee, Seung-Cheol; Jung, Jae-Young; Ahn, Jae-Pyeong; Kim, Young-Yul; Cho, Sung-Youn; Byun, Ji Young; Lee, Kang-Sik; Yang, Seok-Jo; Seok, Hyun-Kwang

2013-01-01

Crystalline Mg-based alloys with a distinct reduction in hydrogen evolution were prepared through both electrochemical and microstructural engineering of the constituent phases. The addition of Zn to Mg-Ca alloy modified the corrosion potentials of two constituent phases (Mg + Mg2Ca), which prevented the formation of a galvanic circuit and achieved a comparable corrosion rate to high purity Mg. Furthermore, effective grain refinement induced by the extrusion allowed the achievement of much lower corrosion rate than high purity Mg. Animal studies confirmed the large reduction in hydrogen evolution and revealed good tissue compatibility with increased bone deposition around the newly developed Mg alloy implants. Thus, high strength Mg-Ca-Zn alloys with medically acceptable corrosion rate were developed and showed great potential for use in a new generation of biodegradable implants. PMID:23917705

The Research and Application of Sustainable Long-release Carbon Material with Agricultural Waste

Science.gov (United States)

Wen, Z.

2017-12-01

(1) The element analysis shown that ten kinds of agricultural wastes containing a certain amount of C, N, H elements, the highest content of C element, and t value ranges from 36.02% 36.02%, and the variation of C, N, H elements content in difference materials was not significant. The TOC concentration of sugar cane was up to 38.66 mg·g-1, and quality ratio was 39‰, significantly lower than C elements content. The released TOC quality of the rest materials were 2.36 2.36 mg·g-1, and the order from high to low were the soybean straw, rice straw, corn straw, rice husk, poplar branches, wheat straw, reeds, corn cob and wood chips respectively. The long-term leaching experiment of selected Optimized agricultural waste showed that the TOC content in leaching solution rise rapidly to peak value and was stable afterwards, with the concentration of 4.59 19.46 mg·g-1. The TOC releasing amount order was same with the short-term leaching experiment. (2) The releasing of nitrate nitrogen in ten kinds of agricultural waste was low (corn straw was up to 0.12mg·g-1, and the rest were all below 0.04mg·g-1 without accumulation. Most of the ammonia nitrogen concentration in leachate was lower than 0.3mg·g-1. The kjeldahl nitrogen in the corn straw, soybean straw, rice straw, reed, rice husk, and sugar cane leachate (0.81 1.65mg·g-1) were higher than that of poplar branches, corn cob and wood chips (corn straw, rice husk and wheat straw leachate. Above all, it can be concluded that the sugar cane, corn straw, rice husk, wheat straw, corn cob, wood were ideal carbon source material in ten kinds of agricultural.

Prevalence of gastroduodenal ulcers/erosions in patients taking low-dose aspirin with either 15 mg/day of lansoprazole or 40 mg/day of famotidine: The OITA-GF study 2

Science.gov (United States)

2013-01-01

Background The preventive effects of histamine 2 receptor antagonists vs. proton pump inhibitors on low-dose aspirin (LDA)-related gastroduodenal mucosal injury have not been fully investigated. We conducted a cross-sectional study to compare the prevalence of gastroduodenal ulcers or erosions in patients taking LDA with either 40 mg/day of famotidine or 15 mg/day of lansoprazole for at least three months. Methods Of 84 eligible patients, two taking 40 mg/day of famotidine and four taking 15 mg/day of lansoprazole refused to undergo upper gastrointestinal endoscopy. Ultimately, we performed upper gastrointestinal endoscopy in 78 patients taking either 40 mg/day of famotidine (group F, n = 31) or 15 mg/day of lansoprazole (group L, n = 47). The prevalence of gastroduodenal ulcers or erosions and the magnitude of gastric mucosal injury evaluated using modified Lanza scores were compared between the two groups. Results No patients in either group had gastroduodenal ulcers. Gastroduodenal erosions were more prevalent in group F than in group L (48.4% vs. 17.0%, p = 0.005). The modified Lanza scores (mean ± SD) were significantly higher in group F than in group L (0.9 ± 1.3 vs. 0.3 ± 0.7, p = 0.007). A multivariate logistic regression analysis showed that the use of lansoprazole was negatively associated with gastroduodenal erosions. Conclusions This study suggests that 15 mg/day of lansoprazole may be more effective in preventing the development of LDA-related gastroduodenal erosions than 40 mg/day of famotidine. The preventive effects of these two regimens on the development of LDA-related gastroduodenal ulcers require further investigation. PMID:23531145

Vacancy Clusters on Surfaces of Au Nanoparticles Embedded in MgO

International Nuclear Information System (INIS)

Xu, Jun; Mills, A. P. Jr.; Ueda, A.; Henderson, D. O.; Suzuki, R.; Ishibashi, S.

1999-01-01

MeV implantation of gold ions into MgO(100) followed by annealing is a method to form gold nanoparticles for obtaining modified optical properties. We show from variable-energy positron spectroscopy that clusters of 2 Mg and 2 O vacancies (v 4 ) are attached to the gold nanoparticle surfaces within the projected range (R p ) . We also find that v 4 vacancy clusters are created at depths less than R p , and extend into the region greater than R p due to damage induced by knock-on collisions. (c) 1999 The American Physical Society

Volatile release from self-assembly structured emulsions: effect of monoglyceride content, oil content, and oil type.

Science.gov (United States)

Mao, Like; Roos, Yrjö H; Miao, Song

2013-02-20

Monoglycerides (MGs) can form self-assembled structures in emulsions, which can be used to control volatile release. In this study, initial headspace concentrations (C(initial)), maximum headspace concentrations (C(max)), release rates, and partition coefficients of propanol, diacetyl, hexanal, and limonene were determined in MG structured oil-in-water emulsions using dynamic and static headspace analyses. For all of the volatile compounds, C(initial) values above structured emulsions were significantly lower than those above unstructured emulsions and decreased with increasing MG contents (p triglyceride emulsions than in soybean oil emulsions (p structured emulsions than in unstructured emulsions (p structured emulsions can be potentially used as delivery systems to modulate volatile release.

Perbandingan Gabapentin 600 mg dengan 1.200 mg per Oral Preoperatif terhadap Nilai Visual Analogue Scale dan Pengurangan Kebutuhan Petidin Pascaoperasi pada Modifikasi Mastektomi Radikal

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Ardi Zulfariansyah

2013-12-01

Full Text Available Gabapentin is a GABA analog which has the effect of anti hyperalgesia, anti allodynia, and anti nociceptive. This research was conducted in order to assess the effect of 600mg and 1,200 mg gabapentin given preoperatively to assess visual analogue scale (VAS score and reduction of pethidine requirement. The study was done by conducting a double blind randomized controlled trial on 38 patients, aged 18–65 years, with ASA physical status I–II. Patients were divided into two groups: 600 mg gabapentin and 1,200 mg gabapentin group. The quality of pain was assessed using VAS score. The results were statistically analyzed using Mann-Whitney Test with 95% confidence interval and considered significant if p value <0.05. From the results, the VAS values obtained at rest and during mobilization were significantly different (p<0.05. The 1,200 mg gabapentin group received less additional pethidine (10.5% vs 15.8%, although no significant difference was shown (p=0.631. The conclusion of this study is that administration of 1,200 mg gabapentin per oral pre operatively is better when compared to 600 mg in reducing post operative visual analog scale score in modified radical mastectomy. However, it do not reduce the need for analgesic significantly.

Intercalation and controlled release properties of vitamin C intercalated layered double hydroxide

Energy Technology Data Exchange (ETDEWEB)

Gao, Xiaorui, E-mail: gxr_1320@sina.com [College of Science, Hebei University of Engineering, Handan 056038 (China); School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (United Kingdom); Lei, Lixu [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); O' Hare, Dermot [Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA (United Kingdom); Xie, Juan [College of Science, Hebei University of Engineering, Handan 056038 (China); Gao, Pengran [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Chang, Tao [College of Science, Hebei University of Engineering, Handan 056038 (China)

2013-07-15

Two drug-inorganic composites involving vitamin C (VC) intercalated in Mg–Al and Mg–Fe layered double hydroxides (LDHs) have been synthesized by the calcination–rehydration (reconstruction) method. Powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), and UV–vis absorption spectroscopy indicate a successful intercalation of VC into the interlayer galleries of the LDH host. Studies of VC release from the LDHs in deionised water and in aqueous CO{sub 3}{sup 2−} solutions imply that Mg{sub 3}Al–VC LDH is a better controlled release system than Mg{sub 3}Fe–VC LDH. Analysis of the release profiles using a number of kinetic models suggests a solution-dependent release mechanism, and a diffusion-controlled deintercalation mechanism in deionised water, but an ion exchange process in CO{sub 3}{sup 2−} solution. - Graphical abstract: Vitamin C anions have been intercalated in the interlayer space of layered double hydroxide and released in CO{sub 3}{sup 2−} solution and deionised water. - Highlights: • Vitamin C intercalated Mg–Al and Mg–Fe layered double hydroxides were prepared. • Release property of vitamin C in aqueous CO{sub 3}{sup 2−} solution is better. • Avrami-Erofe’ev and first-order models provide better fit for release results. • Diffusion-controlled and ion exchange processes occur in deionised water. • An ion exchange process occurs in CO{sub 3}{sup 2−} solution.

Effect of Ultraviolet Aging on Rheology and Chemistry of LDH-Modified Bitumen

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Xing Liu

2015-08-01

Full Text Available Layered double hydroxides (LDHs are an ultravioletlight (UV-resistant material. In this study, two types of LDHs (Mg-Al-LDHs and Zn-Al-LDHs were applied to modify bitumen by melt-blending. The effect of ultraviolet aging on the rheology and chemistry of LDH-modified bitumen was studied by means of dynamic shear rheometer (DSR, thin-layer chromatography with flame ionization detection (TLC-FID, Fourier transform infrared spectroscopy (FTIR, and Ultraviolet-Visible (UV-Vis spectrophotometry to reveal the mechanisms of action for LDHs and bitumen. The results showed that within the UV spectra (220–400 nm, the reflectance of Zn-Al-LDHs was larger than that of Mg-Al-LDHs. These two LDHs have different influences on the performance of bitumen. Mg-Al-LDHs had a more obvious influence on the physical and dynamic rheological properties of bitumen than Zn-Al-LDHs. Zn-Al-LDHs improved the UV-aging resistance of bitumen more. The reason can be that the reflectance of the Zn-Al-LDHs to the UV light is larger than that of the Mg-Al-LDHs. The Zn-Al-LDH-modified bitumen had more potential to improve the UV-aging resistance during the service life of asphalt pavement.

Fission gas release from oxide fuels at high burnups (AWBA development program)

International Nuclear Information System (INIS)

Dollins, C.C.

1981-02-01

The steady state gas release, swelling and densification model previously developed for oxide fuels has been modified to accommodate the slow transients in temperature, temperature gradient, fission rate and pressure that are encountered in normal reactor operation. The gas release predictions made by the model were then compared to gas release data on LMFBR-EBRII fuels obtained by Dutt and Baker and reported by Meyer, Beyer, and Voglewede. Good agreement between the model and the data was found. A comparison between the model and three other sets of gas release data is also shown, again with good agreement

Development of controlled release spheroids using Buchananiacochinchinesis gum

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Narayan Babulal Gaikwad

2013-03-01

Full Text Available Chirauli nut gum was isolated from the bark of Buchanania cochinchinesis (fam. Anacadiacea and was used as a release modifier for the preparation of Diclofenac sodium spheroids using the extrusion spheronization technique. The process was studied for the effects on variables when making spheroids with satisfactory particle shape, size and size distribution. The prepared spheroids were characterized for surface morphology, qualitative surface porosity, friability, bulk density and flow properties. In vitro studies demonstrated that the release exhibited Fickian diffusion kinetics which was confirmed by the Higuchi and the Korsmeyer-Peppas models. The physico-chemical parameters of the gum could be correlated to the in vitro dissolution profile of the spheroids. The spheroids were not able to sustain the drug releases over 12 hours. A greater concentration of Chirauli nut gum and a process that can accommodate such greater concentrations may produce a formulation capable of significant sustained release.

The effect of tartrazine on histamine release from rat peritoneal mast cells.

Science.gov (United States)

Safford, R J; Goodwin, B F

1984-01-01

The release of histamine from purified rat peritoneal mast cells induced by specific antigen (egg albumin), compound 48/80 and calcium ionophore A23187 was modified by tartrazine. Histamine release induced by 48/80 and antigen was inhibited by the presence of 10(-5) to 10(-2)M tartrazine. The inhibitory effect on egg albumin induced histamine release was maximal when the tartrazine was added simultaneously with egg albumin, and was reduced by increased preincubation of the cells with tartrazine. Tartrazine had a small inhibitory effect on ionophore induced release at high concentrations, but augmented histamine release at tartrazine concentrations of 10(-3) and 10(-4)M. Augmentation of ionophore induced release was maximal at between 0-5 min preincubation of the cells with tartrazine.

Controlled release of isoproturon, imidacloprid, and cyromazine from alginate-bentonite-activated carbon formulations.

Science.gov (United States)

Garrido-Herrera, F J; Gonzalez-Pradas, E; Fernandez-Pérez, M

2006-12-27

Different alginate-based systems of isoproturon, imidacloprid, and cyromazine have been investigated in order to obtain controlled release (CR) properties. The basic formulation [sodium alginate (1.50%), pesticide (0.30%), and water] was modified using different amounts of bentonite and activated carbon. The higher values of encapsulation efficiency corresponded to those formulations prepared with higher percentages of activated carbon, showing higher encapsulation efficiency values for isoproturon and imidacloprid than for cyromazine, which has a higher water solubility. The kinetic experiments of imidacloprid/isoproturon release in water have shown us that the release rate is higher in imidacloprid systems than in those prepared with isoproturon. Moreover, it can be deduced that the use of bentonite and/or activated carbon sorbents reduces the release rate of the isoproturon and imidacloprid in comparison with the technical product and with alginate formulation without modifying agents. The highest decrease in release rate corresponds to the formulations prepared with the highest percentage of activated carbon. The water uptake, permeability, and time taken for 50% of the active ingredient to be released into water, T50, were calculated to compare the formulations. On the basis of a parameter of an empirical equation used to fit the pesticide release data, the release of isoproturon and imidacloprid from the various formulations into water is controlled by a diffusion mechanism. The sorption capacity of the sorbents and the permeability of the formulations were the most important factors modulating pesticide release. Finally, a linear correlation of the T50 values and the content of activated carbon in formulations were obtained.

Cadmium Adsorption on HDTMA Modified Montmorillionite

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Mohd. Elmuntasir I. Ahmed

2009-06-01

Full Text Available In this paper the possibility of cadmium removal from aqueous solutions by adsorption onto modified montmorillonite clay is investigated. Batch adsorption experiments performed revealed an enhanced removal of cadmium using HDTMA modified montmorillonite to 100% of its exchange capacity. Modified montmorillonite adsorption capacity increases at higher pHs suggesting adsorption occurs as a result of surface precipitation and HDTMA complex formation due to the fact that the original negatively charged montmorillonite is now covered by a cationic layer of HDTMA. Adsorption isotherms generated followed a Langmuir isotherm equation possibly indicating a monolayer coverage. Adsorption capacities of up to 49 mg/g and removals greater than 90% were achieved. Anionic selectivity of the HDTMA modified monmorillonite is particularly advantageous in water treatment applications where high concentrations of less adsorbable species are present, and the lack of organoclay affinity for these species may allow the available capacity to be utilized selectively by the targeted species.

Design and characteristics of gellan gum beads for modified release of meloxicam.

Science.gov (United States)

Osmałek, Tomasz; Milanowski, Bartłomiej; Froelich, Anna; Szybowicz, Mirosław; Białowąs, Wojciech; Kapela, Marcin; Gadziński, Piotr; Ancukiewicz, Katarzyna

2017-08-01

The aim of the presented work was to design, formulate and evaluate the properties of low-acyl gellan macro beads with the potential application as carriers for oral delivery of meloxicam (MLX) in the prophylaxis of colorectal cancer. The beads were obtained by means of ionotropic gelation technique. Calcium chloride (1.0%, 9.0 × 10 -2  M) was used as the cross-linking agent. Nine different polymer, drug and surfactant (Tween ® 80) mixtures were used for production of the beads. The quantitative compositions of the mixtures were generated with the application of the Design of Experiments (DoE) modulus from the STATISTICA Software. The prepared formulations revealed 7.2-27.0% of drug loading and 29.2-50.7% drug encapsulation efficiency. It turned out that 0.5% amount of gellan gum in the mixtures was not sufficient to obtain spherical beads. The morphology and surface of the dried beads were analyzed by SEM. Raman spectra confirmed that MLX did not undergo structural changes during production of the beads. The swelling behavior and degradation of the beads were evaluated in three simulated gastrointestinal fluids at different pH (1.2; 4.5; 6.8). The MLX in vitro release studies were conducted on USP apparatus IV, working in the open loop mode. The obtained results showed that MLX release from the dried beads was pH-dependent. The formulations obtained from mixtures containing 1.0 and 1.5% of gellan may be considered as oral dosage forms for MLX, intended to omit the stomach and release the drug in the distal parts of the gastrointestinal tract.

Secondary effects of anion exchange on chloride, sulfate, and lead release: systems approach to corrosion control.

Science.gov (United States)

Willison, Hillary; Boyer, Treavor H

2012-05-01

Water treatment processes can cause secondary changes in water chemistry that alter finished water quality including chloride, sulfate, natural organic matter (NOM), and metal release. Hence, the goal of this research was to provide an improved understanding of the chloride-to-sulfate mass ratio (CSMR) with regards to chloride and sulfate variations at full-scale water treatment plants and corrosion potential under simulated premise plumbing conditions. Laboratory corrosion studies were conducted using Pb-Sn solder/Cu tubing galvanic cells exposed to model waters with low (approx. 5 mg/L Cl(-) and 10 mg/L SO(4)(2-)) and high (approx. 50 mg/L Cl(-) and 100 mg/L SO(4)(2-)) concentrations of chloride and sulfate at a constant CSMR of ≈ 0.5. The role of NOM during corrosion was also evaluated by changing the type of organic material. In addition, full-scale sampling was conducted to quantify the raw water variability of chloride, sulfate, and NOM concentrations and the changes to these parameters from magnetic ion exchange treatment. Test conditions with higher concentrations of chloride and sulfate released significantly more lead than the lower chloride and sulfate test waters. In addition, the source of NOM was a key factor in the amount of lead released with the model organic compounds yielding significantly less lead release than aquatic NOM. Copyright © 2012 Elsevier Ltd. All rights reserved.

Enhanced fluoride adsorption using Al (III) modified calcium hydroxyapatite

International Nuclear Information System (INIS)

Nie, Yulun; Hu, Chun; Kong, Chuipeng

2012-01-01

Highlights: ► Al modified hydroxyapatite possessed a higher defluoridation capacity of 32.57 mg/g. ► Hydroxyl groups on the surface of Al-HAP was the adsorption sites for F − removal. ► Enhanced F − removal over Al-HAP was attributed to the modification with aluminum. - Abstract: Aluminum-modified hydroxyapatite (Al-HAP) was prepared and characterized using XRD and BET analyses. Al-HAP possessed higher defluoridation capacity (DC) of 32.57 mgF − /g than unmodified hydroxyapatite (HAP) which showed a DC of 16.38 mgF − /g. The effect of Al/Ca atomic ratio in Al-HAP, solution pH and co-existing anions was further studied. The results indicated that the adsorption data could be well described by the Langmuir isotherm model and the adsorption kinetic followed the pseudo-second-order model. The pH changes during the adsorption process suggested that the -OH on the surface of Al-HAP was the adsorption sites. The more adsorption sites were formed on Al modified HAP, which possessed abundant surface hydroxyl groups, resulting in higher efficiency of F − removal. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were calculated in order to understand the nature of adsorption process. The results revealed that the adsorption reaction was a spontaneous and endothermic process.

Nanocomposite hydrogels stabilized by self-assembled multivalent bisphosphonate-magnesium nanoparticles mediate sustained release of magnesium ion and promote in-situ bone regeneration.

Science.gov (United States)

Zhang, Kunyu; Lin, Sien; Feng, Qian; Dong, Chaoqun; Yang, Yanhua; Li, Gang; Bian, Liming

2017-12-01

Hydrogels are appealing biomaterials for applications in regenerative medicine due to their tunable physical and bioactive properties. Meanwhile, therapeutic metal ions, such as magnesium ion (Mg 2+ ), not only regulate the cellular behaviors but also stimulate local bone formation and healing. However, the effective delivery and tailored release of Mg 2+ remains a challenge, with few reports on hydrogels being used for Mg 2+ delivery. Bisphosphonate exhibits a variety of specific bioactivities and excellent binding affinity to multivalent cations such as Mg 2+ . Herein, we describe a nanocomposite hydrogel based on hyaluronic acid and self-assembled bisphosphonate-magnesium (BP-Mg) nanoparticles. These nanoparticles bearing acrylate groups on the surface not only function as effective multivalent crosslinkers to strengthen the hydrogel network structure, but also promote the mineralization of hydrogels and mediate sustained release of Mg 2+ . The released Mg 2+ ions facilitate stem cell adhesion and spreading on the hydrogel substrates in the absence of cell adhesion ligands, and promote osteogenesis of the seeded hMSCs in vitro. Furthermore, the acellular porous hydrogels alone can support in situ bone regeneration without using exogenous cells and inductive agents, thereby greatly simplifying the approaches of bone regeneration therapy. In this study, we developed a novel bioactive nanocomposite hydrogel based on hyaluronic acid and self-assembled bisphosphonate-magnesium (BP-Mg) nanoparticles. Such hydrogels are stabilized by the multivalent crosslinking domains formed by the aggregation of Ac-BP-Mg NPs, and therefore show enhanced mechanical properties, improved capacity for mineralization, and controlled release kinetics of Mg 2+ . Moreover, the released Mg 2+ can enhance cell adhesion and spreading, and further promote the osteogenic differentiation of hMSCs. Owing to these unique properties, these acellular hydrogels alone can well facilitate the in vivo

Once daily, extended release ciprofloxacin for complicated urinary tract infections and acute uncomplicated pyelonephritis.

Science.gov (United States)

Talan, David A; Klimberg, Ira W; Nicolle, Lindsay E; Song, James; Kowalsky, Steven F; Church, Deborah A

2004-02-01

We assessed the efficacy and safety of 1,000 mg extended release ciprofloxacin orally once daily vs conventional 500 mg ciprofloxacin orally twice daily, each for 7 to 14 days, in patients with a complicated urinary tract infection (cUTI) or acute uncomplicated pyelonephritis (AUP). In this prospective, randomized, double-blind, North American multicenter clinical trial adults were stratified based on clinical presentation of cUTI or AUP and randomized to extended release ciprofloxacin or ciprofloxacin twice daily. Efficacy valid patients had positive pretherapy urine cultures (105 or greater cFU/ml) and pyuria within 48 hours of study entry. Bacteriological and clinical outcomes were assessed at the test of cure visit (5 to 11 days after therapy) and the late followup visit (28 to 42 days after therapy). The intent to treat population comprised 1,035 patients (extended release ciprofloxacin in 517 and twice daily in 518), of whom 435 were efficacy valid (cUTI in 343 and AUP in 92). For efficacy valid patients (cUTI and AUP combined) bacteriological eradication rates at test of cure were 89% (183 of 206) vs 85% (195 of 229) (95% CI -2.4%, 10.3%) and clinical cure rates were 97% (198 of 205) vs 94% (211 of 225) (95% CI -1.2%, 6.9%) for extended release vs twice daily ciprofloxacin. Late followup outcomes were consistent with test of cure findings. Eradication rates for Escherichia coli, which accounted for 58% of pathogens, were 97% or greater per group. Drug related adverse event rates were similar for extended release and twice daily ciprofloxacin (13% and 14%, respectively). Extended release ciprofloxacin at a dose of 1,000 mg once daily was as safe and effective as conventional treatment with 500 mg ciprofloxacin twice daily, each given orally for 7 to 14 days in adults with cUTI or AUP. It provides a convenient, once daily, empirical treatment option.

Simultaneous sorption of fluoride and arsenic ions (V) in a naturally occurring material modified with iron and aluminum

International Nuclear Information System (INIS)

Vazquez M, G.

2016-01-01

In this research, two materials, zeolite and pozzolans from the States of Oaxaca and Mexico, were used respectively, which were modified to evaluate their efficiencies to remove F and As(V) ions from solution and natural water. The materials were modified with iron and aluminum using an electrochemical cell, and with the hydroxides formed with iron and aluminum chloride solutions. The natural and modified materials were characterized by X-ray diffraction, scanning electron microscopy with energy X-ray disperse spectroscopy analysis, specific area and the point of zero charge (pHzpc). F- and As(V) adsorption properties of both materials were investigated. Experimental data on the sorption processes of F- ions by modified zeolite and pozzolans were adjusted to the kinetic models of pseudo-second-order (q e, 0408 mg /g K, 4.33 g / mg h) and Lagergen (q e, 0.807 mg/g K L, 1.83 1/min), respectively. Both materials showed the best fit to the Freundlich isotherm, Kf, 0.33 and 0.64 (mg/g) (L/mg) for pozzolans and zeolite respectively; suggesting a physical adsorption process on a heterogeneous material. Experimental adsorption capacities of pozzolans and modified zeolite for F ions were 0.36 and 0.83 mg/g respectively. The results of the kinetics of adsorption of As(V) were treated with the Largergren, pseudo-second-order and Elovich models; however the adsorption rate was high and consequently the rate constants could not be calculated. The isotherms data were fitted to the Freundlich model and the constants Kf were 6.24 and 11.15 (mg/g) (L/mg) for pozzolans and zeolite respectively. The thermodynamic parameters of the adsorption processes suggest endothermic adsorption for F- ions by both materials and for As(V) by the pozzolans. The free energy values ΔG indicate spontaneous processes and not spontaneous for F- ions by pozzolans. The adsorption of As (V) by the pozzolans presented an exothermic and spontaneous behavior. Finally, a study was performed in columns with

Unusual behaviour of an immature loggerhead turtle released in the Alboran Sea

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Bellido, J. J.

2010-06-01

Full Text Available A juvenile loggerhead turtle with buoyancy problems was captured in the Alboran Sea (Mediterranean Sea, south of Spain and released 14 months later after healing. Six days after the release, the turtle was seen swimming 42 km from the point of release, displaying unusual behaviour. We re-captured and released it again, 95 nautical miles offshore, near the Alboran Island. Ten days later the turtle arrived at the beach close to where it had been maintained in captivity. We discuss these findings in the context of behavioural alteration and habituation in released sea turtles. Capture-mark-recapture studies of sea turtles should be approached with caution as manipulated animals may modify their usual behaviour.

Development of efficient amine-modified mesoporous silica SBA-15 for CO2 capture

International Nuclear Information System (INIS)

Zhang, Xiaoyun; Qin, Hongyan; Zheng, Xiuxin; Wu, Wei

2013-01-01

Graphical abstract: - Highlights: • A secondary amine AN-TEPA is used to modify the SBA-15. • CO 2 adsorption capacity (180.1 mg g −1 -adsorbent for 70% amine loading) is high. • The sorbent exhibits a high stability after 12 cycling runs. • The modified SBA-15 achieves complete desorption at low temperature (100 °C). - Abstract: A novel CO 2 sorbent was prepared by impregnating mesoporous silica, SBA-15, with acrylonitrile (AN)-modified tetraethylenepentamine (TEPA) in order to increase CO 2 adsorption capacity and improve cycling stability. The mesoporous silica with pre- and post-surface modification was investigated by X-ray diffraction characterization (XRD), N 2 adsorption–desorption test (N 2 -BET), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The adsorption/desorption performance of S-TN (TN: AN modified TEPA) and S-TEPA was studied by dynamic adsorption. Test results showed that the solid base-impregnated SBA-15 demonstrated high CO 2 adsorption capacity (180.1 mg g −1 -adsorbent for 70% amine loading level). Compared to S-TEPA (24.1% decrease of initial capacity), S-TN with 50% amine loading exhibited improved cycling stability, 99.9% activity reserved (from initial 153.0 mg g −1 to 151.3 mg g −1 ) after 12 cycles of adsorption/desorption at 100 °C. A mechanism of molecular structure of the loaded amine was attributed to the improved performance

Description of tritium release from lithium titanate at constant temperature

Energy Technology Data Exchange (ETDEWEB)

Pena, L; Lagos, S; Jimenez, J; Saravia, E [Comision Chilena de Energia Nuclear, Santiago (Chile)

1998-03-01

Lithium Titanate Ceramics have been prepared by the solid-state route, pebbles and pellets were fabricated by extrusion and their microstructure was characterized in our laboratories. The ceramic material was irradiated in the La Reina Reactor, RECH-1. A study of post-irradiation annealing test, was performed measuring Tritium release from the Lithium Titanate at constant temperature. The Bertone`s method modified by R. Verrall is used to determine the parameters of Tritium release from Lithium Titanate. (author)

Chromium(III) and chromium(VI) release from leather during 8 months of simulated use.

Science.gov (United States)

Hedberg, Yolanda S; Lidén, Carola

2016-08-01

Chromium (Cr) release from Cr-tanned leather articles is a major cause of Cr contact dermatitis. It has been suggested that Cr(VI) release from leather is not necessarily an intrinsic property of the leather, but is strongly dependent on environmental conditions. To test this hypothesis for long-term (8 months) simulated use. The release of total Cr and Cr(VI) from Cr-tanned, unfinished leather was analysed in subsequent phosphate buffer (pH 8.0) immersions for a period of 7.5 months. The effect of combined ultraviolet treatment and alkaline solution (pH 12.1) was tested. Dry storage [20% relative humidity (RH)] was maintained between immersions. Atomic absorption spectroscopy, X-ray fluorescence and diphenylcarbazide tests were used. Cr(VI) release was dependent on previous dry storage or alkaline treatment, but not on duration or number of previous immersions. Cr(III) release decreased with time. Fifty-two percent of the total Cr released during the last immersion period was Cr(VI). Cr(VI) release exceeded 9 mg/kg in all immersion periods except in the first 10-day immersion (2.6 mg/kg). Cr(VI) release is primarily determined by environmental factors (RH prior to immersion, solution pH, and antioxidant content). The RH should be kept low prior to testing Cr(VI) release from leather. © 2016 The Authors. Contact Dermatitis published by John Wiley & Sons Ltd.

Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

Energy Technology Data Exchange (ETDEWEB)

Zargarian, S. Sh.; Haddadi-Asl, V., E-mail: haddadi@aut.ac.ir; Hematpour, H. [Amirkabir University of Technology, Department of Polymer Engineering and Color Technology (Iran, Islamic Republic of)

2015-05-15

Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite.

Carboxylic acid functionalization of halloysite nanotubes for sustained release of diphenhydramine hydrochloride

International Nuclear Information System (INIS)

Zargarian, S. Sh.; Haddadi-Asl, V.; Hematpour, H.

2015-01-01

Halloysite nanotubes (HNT) (cylindrical shape with external diameter and length in the range of 30–80 nm and 0.2–1 µm, respectively) were functionalized with 3-aminopropyltriethoxysilane (APTES) from hydroxyl groups by a coupling reaction. Subsequently, maleic anhydride was attached to the APTES moieties to yield carboxylic acid-functionalized HNT. Loading and subsequent release of a model drug molecule diphenhydramine hydrochloride (DPH) on modified and unmodified nanotubes were investigated. Morphology of HNT was studied by electron microscopy. Successful attachment of APTES and carboxylic acid groups to halloysite and drug loading were evaluated by Fourier transform infrared spectroscopy. The amount of surface modification and drug adsorption capacity were calculated via thermogravimetric analysis. The ordered crystal structure of loaded drug was evaluated by X-ray diffraction. UV–Visible spectrophotometer was used to study drug release from modified and unmodified samples. Carboxylated halloysite exhibits higher loading capacity and prolonged release of DPH as compared to that of the natural halloysite

Spinal cord thyrotropin releasing hormone receptors of morphine tolerant-dependent and abstinent rats

Energy Technology Data Exchange (ETDEWEB)

Rahmani, N.H.; Gulati, A.; Bhargava, H.N. (Univ. of Illinois, Chicago (USA))

1990-07-01

The effect of chronic administration of morphine and its withdrawal on the binding of 3H-(3-MeHis2)thyrotropin releasing hormone (3H-MeTRH) to membranes of the spinal cord of the rat was determined. Male Sprague-Dawley rats were implanted with either 6 placebo or 6 morphine pellets (each containing 75-mg morphine base) during a 7-day period. Two sets of animals were used. In one, the pellets were left intact at the time of sacrificing (tolerant-dependent) and in the other, the pellets were removed 16 hours prior to sacrificing (abstinent rats). In placebo-pellet-implanted rats, 3H-MeTRH bound to the spinal cord membranes at a single high affinity binding site with a Bmax of 21.3 +/- 1.6 fmol/mg protein, and an apparent dissociation constant Kd of 4.7 +/- 0.8 nM. In morphine tolerant-dependent or abstinent rats, the binding constants of 3H-MeTRH to spinal cord membranes were unaffected. Previous studies from this laboratory indicate that TRH can inhibit morphine tolerance-dependence and abstinence processes without modifying brain TRH receptors. Together with the present results, it appears that the inhibitory effect of TRH on morphine tolerance-dependence and abstinence is probably not mediated via central TRH receptors but may be due to its interaction with other neurotransmitter systems.

Applying a Modified Triad Approach to Investigate Wastewater lines

International Nuclear Information System (INIS)

Pawlowicz, R.; Urizar, L.; Blanchard, S.; Jacobsen, K.; Scholfield, J.

2006-01-01

Approximately 20 miles of wastewater lines are below grade at an active military Base. This piping network feeds or fed domestic or industrial wastewater treatment plants on the Base. Past wastewater line investigations indicated potential contaminant releases to soil and groundwater. Further environmental assessment was recommended to characterize the lines because of possible releases. A Remedial Investigation (RI) using random sampling or use of sampling points spaced at predetermined distances along the entire length of the wastewater lines, however, would be inefficient and cost prohibitive. To accomplish RI goals efficiently and within budget, a modified Triad approach was used to design a defensible sampling and analysis plan and perform the investigation. The RI task was successfully executed and resulted in a reduced fieldwork schedule, and sampling and analytical costs. Results indicated that no major releases occurred at the biased sampling points. It was reasonably extrapolated that since releases did not occur at the most likely locations, then the entire length of a particular wastewater line segment was unlikely to have contaminated soil or groundwater and was recommended for no further action. A determination of no further action was recommended for the majority of the waste lines after completing the investigation. The modified Triad approach was successful and a similar approach could be applied to investigate wastewater lines on other United States Department of Defense or Department of Energy facilities. (authors)

Development and evaluation of a biocide release system for prolonged antifungal activity in finishing materials

NARCIS (Netherlands)

Eversdijk, J.; Erich, S.J.F.; Hermanns, S.P.M.; Adan, O.C.G.; Bolle, de M.; Meyer, de K.; Bylemans, D.; Bekker, M.; Cate, ten A.T.

2012-01-01

This paper focuses on the use of modified nano-clay particles as a controlled release system for biocides from building materials. Different (model) biocides were incorporated in a biocide/nano-clay composite and subsequently the release of the biocides was monitored under different environmental

Modified Polymeric Nanoparticles Exert In Vitro Antimicrobial Activity Against Oral Bacteria.

Science.gov (United States)

Toledano-Osorio, Manuel; Babu, Jegdish P; Osorio, Raquel; Medina-Castillo, Antonio L; García-Godoy, Franklin; Toledano, Manuel

2018-06-14

Polymeric nanoparticles were modified to exert antimicrobial activity against oral bacteria. Nanoparticles were loaded with calcium, zinc and doxycycline. Ions and doxycycline release were measured by inductively coupled plasma optical emission spectrometer and high performance liquid chromatography. Porphyromonas gingivalis , Lactobacillus lactis , Streptoccocus mutans , gordonii and sobrinus were grown and the number of bacteria was determined by optical density. Nanoparticles were suspended in phosphate-buffered saline (PBS) at 10, 1 and 0.1 mg/mL and incubated with 1.0 mL of each bacterial suspension for 3, 12, and 24 h. The bacterial viability was assessed by determining their ability to cleave the tetrazolium salt to a formazan dye. Data were analyzed by ANOVA and Scheffe’s F ( p Nanoparticles (60% to 99% reduction) followed by Ca-Nanoparticles or Zn-Nanoparticles (30% to 70% reduction) and finally the non-doped nanoparticles (7% to 35% reduction). P. gingivalis , S. mutans and L. lactis were the most susceptible bacteria, being S. gordonii and S. sobrinus the most resistant to the tested nanoparticles.

Comparative steady-state pharmacokinetic study of an extended-release formulation of itopride and its immediate-release reference formulation in healthy volunteers

Directory of Open Access Journals (Sweden)

Yoon S

2014-01-01

Full Text Available Seonghae Yoon,1,* Howard Lee,2,* Tae-Eun Kim,1 SeungHwan Lee,1 Dong-Hyun Chee,3 Joo-Youn Cho,1 Kyung-Sang Yu,1 In-Jin Jang1 1Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, 2Clinical Trials Center, Seoul National University Hospital, 3AbbVie Ltd., Seoul, Republic of Korea *These authors contributed equally to this work Background: This study was conducted to compare the oral bioavailability of an itopride extended-release (ER formulation with that of the reference immediate-release (IR formulation in the fasting state. The effect of food on the bioavailability of itopride ER was also assessed. Methods: A single-center, open-label, randomized, multiple-dose, three-treatment, three-sequence, crossover study was performed in 24 healthy male subjects, aged 22–48 years, who randomly received one of the following treatments for 4 days in each period: itopride 150 mg ER once daily under fasting or fed conditions, or itopride 50 mg IR three times daily in the fasting state. Steady-state pharmacokinetic parameters of itopride, including peak plasma concentration (Cmax and area under the plasma concentration versus time curve over 24 hours after dosing (AUC0–24h, were determined by noncompartmental analysis. The geometric mean ratio of the pharmacokinetic parameters was derived using an analysis of variance model. Results: A total of 24 healthy Korean subjects participated, 23 of whom completed the study. The geometric mean ratio and its 90% confidence interval of once-daily ER itopride versus IR itopride three times a day for AUC0–24h were contained within the conventional bioequivalence range of 0.80–1.25 (0.94 [0.88–1.01], although Cmax was reached more slowly and was lower for itopride ER than for the IR formulation. Food delayed the time taken to reach Cmax for itopride ER, but AUC0–24h was not affected. There were no serious adverse events and both formulations were

Activation of 5-HT2 receptors enhances the release of acetylcholine in the prefrontal cortex and hippocampus of the rat.

Science.gov (United States)

Nair, Sunila G; Gudelsky, Gary A

2004-09-15

The role of 5-HT2 receptors in the regulation of acetylcholine (ACh) release was examined in the medial prefrontal cortex and dorsal hippocampus using in vivo microdialysis. The 5-HT(2A/2C) agonist +/-1-(2,5-dimethoxy-4-iodophenyl) -2- aminopropane hydrochloride (DOI) (1 and 2 mg/kg, i.p.) significantly increased the extracellular concentration of ACh in both brain regions, and this response was attenuated in rats treated with the 5-HT(2A/2B/2C) antagonist LY-53,857 (3 mg/kg, i.p.). Treatment with LY-53,857 alone did not significantly alter ACh release in either brain region The 5-HT(2C) agonist 6-chloro-2-(1-piperazinyl)-pyrazine) (MK-212) (5 mg/kg, i.p.) significantly enhanced the release of ACh in both the prefrontal cortex and hippocampus, whereas the 5-HT2 agonist mescaline (10 mg/kg, i.p.) produced a 2-fold increase in ACh release only in the prefrontal cortex. Intracortical, but not intrahippocampal, infusion of DOI (100 microM) significantly enhanced the release of ACh, and intracortical infusion of LY-53,857 (100 microM) significantly attenuated this response. These results suggest that the release of ACh in the prefrontal cortex and hippocampus is influenced by 5-HT2 receptor mechanisms. The increase in release of ACh induced by DOI in the prefrontal cortex, but not in the hippocampus, appears to be due to 5-HT2 receptor mechanisms localized within this brain region. Furthermore, it appears that the prefrontal cortex is more sensitive than the dorsal hippocampus to the stimulatory effect of 5-HT2 agonists on ACh release.

Biowaiver Monograph for Immediate-Release Solid Oral Dosage Forms: Amoxicillin Trihydrate.

Science.gov (United States)

Thambavita, Dhanusha; Galappatthy, Priyadarshani; Mannapperuma, Uthpali; Jayakody, Lal; Cristofoletti, Rodrigo; Abrahamsson, Bertil; Groot, Dirk W; Langguth, Peter; Mehta, Mehul; Parr, Alan; Polli, James E; Shah, Vinod P; Dressman, Jennifer

2017-10-01

Literature and experimental data relevant to waiver of in vivo bioequivalence (BE) testing for the approval of immediate-release solid oral dosage forms containing amoxicillin trihydrate are reviewed. Solubility and permeability characteristics according to the Biopharmaceutics Classification System (BCS), therapeutic uses, therapeutic index, excipient interactions, as well as dissolution and BE and bioavailability studies were taken into consideration. Solubility and permeability studies indicate that amoxicillin doses up to 875 mg belong to BCS class I, whereas 1000 mg belongs to BCS class II and doses of more than 1000 mg belong to BCS class IV. Considering all aspects, the biowaiver procedure can be recommended for solid oral products of amoxicillin trihydrate immediate-release preparations containing amoxicillin as the single active pharmaceutical ingredient at dose strengths of 875 mg or less, provided (a) only the excipients listed in this monograph are used, and only in their usual amounts, (b) the biowaiver study is performed according to the World Health Organization-, U.S. Food and Drug Administration-, or European Medicines Agency-recommended method using the innovator as the comparator, and (c) results comply with criteria for "very rapidly dissolving" or "similarly rapidly dissolving." Products containing other excipients and those containing more than 875 mg amoxicillin per unit should be subjected to an in vivo BE study. Copyright © 2017 American Pharmacists Association®. All rights reserved.

[Characteristics of dissolved organic carbon release under inundation from typical grass plants in the water-level fluctuation zone of the Three Gorges Reservoir area].

Science.gov (United States)

Tan, Qiu-Xia; Zhu, Boi; Hua, Ke-Ke

2013-08-01

The water-level fluctuation zone of the Three Gorges Reservoir (TGR) exposes in spring and summer, then, green plants especially herbaceous plants grow vigorously. In the late of September, water-level fluctuation zone of TGR goes to inundation. Meanwhile, annually accumulated biomass of plant will be submerged for decaying, resulting in organism decomposition and release a large amount of dissolved organic carbon (DOC). This may lead to negative impacts on water environment of TGR. The typical herbaceous plants from water-level fluctuation zone were collected and inundated in the laboratory for dynamic measurements of DOC concentration of overlying water. According to the determination, the DOC release rates and fluxes have been calculated. Results showed that the release process of DOC variation fitted in a parabolic curve. The peak DOC concentrations emerge averagely in the 15th day of inundation, indicating that DOC released quickly with organism decay of herbaceous plant. The release process of DOC could be described by the logarithm equation. There are significant differences between the concentration of DOC (the maximum DOC concentration is 486.88 mg x L(-1) +/- 35.97 mg x L(-1) for Centaurea picris, the minimum is 4.18 mg x L(-1) +/- 1.07 mg x L(-1) for Echinochloacrus galli) and the release amount of DOC (the maximum is 50.54 mg x g(-1) for Centaurea picris, the minimum is 6.51 mg x g(-1) for Polygonum hydropiper) due to different characteristics of plants, especially, the values of C/N of herbaceous plants. The cumulative DOC release quantities during the whole inundation period were significantly correlated with plants' C/N values in linear equations.

The Adsorption Mechanism of Modified Activated Carbon on Phenol

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Lin J. Q.

2016-01-01

Full Text Available Modified activated carbon was prepared by thermal treatment at high temperature under nitrogen flow. The surface properties of the activated carbon were characterized by Boehm titration, BET and point of zero charge determination. The adsorption mechanism of phenol on modified activated carbon was explained and the adsorption capacity of modified activated carbon for phenol when compared to plain activated carbon was evaluated through the analysis of adsorption isotherms, thermodynamic and kinetic properties. Results shows that after modification the surface alkaline property and pHpzc value of the activated carbon increase and the surface oxygen-containing functional groups decrease. The adsorption processes of the plain and modified carbon fit with Langmuir isotherm equation well, and the maximum adsorption capacity increase from 123.46, 111.11, 103.09mg/g to 192.31, 178.57, 163,93mg/g under 15, 25 and 35°C after modification, respectively. Thermodynamic parameters show that the adsorption of phenol on activated carbon is a spontaneously exothermic process of entropy reduction, implying that the adsorption is a physical adsorption. The adsorption of phenol on activated carbon follows the pseudo-second-order kinetics (R2>0.99. The optimum pH of adsorption is 6~8.

Drug Release Profile from Calcium-Induced Alginate-Phosphate Composite Gel Beads

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Yoshifumi Murata

2009-01-01

Full Text Available Calcium-induced alginate-phosphate composite gel beads were prepared, and model drug release profiles were investigated in vitro. The formation of calcium phosphate in the alginate gel matrix was observed and did not affect the rheological properties of the hydrogel beads. X-ray diffraction patterns showed that the calcium phosphate does not exist in crystalline form in the matrix. The initial release amount and release rate of a water-soluble drug, diclofenac, from the alginate gel beads could be controlled by modifying the composition of the matrix with calcium phosphate. In contrast, the release profile was not affected by the modification for hydrocortisone, a drug only slightly soluble in water.

Disease-modifying effect of anthraquinone prodrug with boswellic acid on collagenase-induced osteoarthritis in Wistar rats.

Science.gov (United States)

Dhaneshwar, Suneela; Dipmala, Patil; Abhay, Harsulkar; Prashant, Bhondave

2013-08-01

Diacerein and its active metabolite rhein are promising disease modifying agents for osteoarthritis (OA). Boswellic acid is an active ingredient of Gugglu; a herbal medicine commonly administered in osteoarthritis. Both of them possess excellent anti-inflammatory and anti-arthritic activities. It was thought interesting to conjugate rhein and boswellic acid into a mutual prodrug (DSRB) and evaluate its efficacy on collagenase-induced osteoarthritis in rats wherein the conjugate, rhein, boswellic acid and their physical mixture, were tested based on various parameters. Oral administration of 3.85 mg of rhein, 12.36 mg of boswellic acid and 15.73 mg of DSRB which would release equimolar amounts of rhein and boswellic acid, exhibited significant restoration in rat body weight as compared to the untreated arthritic control group. Increase in knee diameter (mm), due to edema was observed in group injected with collagenase, which reduced significantly with the treatment of conjugate. The hematological parameters (Hb, RBC, WBC and ESR) and biochemical parameters (CRP, SALP, SGOT and SGPT) in the osteoarthritic rats were significantly brought back to normal values on treatment with conjugate. It also showed better anti-ulcer activity than rhein. Further the histopathological studies revealed significant anti-arthritic activity of conjugate when compared with the arthritic control group. In conclusion, the conjugate at the specified dose level of 15.73 mg/kg, p. o. (BID) showed reduction in knee diameter and it could significantly normalize the hematological and biochemical abnormalities in collagenase-induced osteoarthritis in rats. Further the histopathological studies confirmed the additive anti-arthritic effect of DSRB as compared to plain rhein.

Characteristics of inositol trisphosphate mediated Ca2+ release from permeabilized hepatocytes

International Nuclear Information System (INIS)

Joseph, S.K.; Williamson, J.R.

1986-01-01

Ca 2+ release triggered by inositol trisphosphate (IP 3 ) has been measured in saponin-permeabilized hepatocytes with 45 Ca 2+ or Quin 2. The initial rate of Ca 2+ release was not markedly affected by the incubation temperature (175 +/- 40 pmol/s/mg at 30 0 C versus 133 +/- 24 pmol/s/mg at 4 0 C). This result is consistent with the membrane translocation of Ca 2+ occurring through an ion-channel rather than an ion-carrier. The amount of Ca 2+ released by IP 3 was not affected by pH (6.5-8.0) or by compounds that inhibit voltage-gated Ca 2+ channels. La 3+ (100 μM) markedly inhibits the effect of 1 μM IP 3 . The possibility that La 3+ chelates IP 3 cannot be excluded since the effect of La 3+ can be overcome by increasing the IP 3 concentration. IP 3 -mediated Ca 2+ release displays a requirement for a permeant cation in the incubation medium. Optimal release is observed with K + gluconate. Other monovalent cations, with the exception of Li + , can substitute for K + . Permeant anions, at concentrations above 40 mM, inhibit Ca 2+ release produced by IP 3 . Cl - , Br - , I - , and SO 4 2- were equally effective. Ca 2+ release was not inhibited by DIDS or Furosemide. 85 Sr 2+ and 54 Mn 2+ fluxes were also stimulated by IP 3 . These results suggest that IP 3 acts to gate a divalent cation channel. The translocation of positive charge through this channel is balanced by ancillary movements of monovalent cations and anions across the reticular membrane

Comparison of the efficiencies of modified clay with polyethylene glycol and tetradecyl trimethyl ammonium bromide for BTEX removal

Directory of Open Access Journals (Sweden)

Heshmatollah Nourmoradi

2013-01-01

Conclusion: The adsorption capacity of TTAB-Mt (22.11 mg/g was slightly higher than PEG-Mt (18.77 mg/g. With regard to lower toxic effects and lower cost of nonionic surfactants than the cationic type, using the nonionic modified Mt is preferred than cationic modified Mt for the removal of BTEX from aqueous solution.

[Preparation of HDTMA-modified Zeolite and Its Performance in Nitro-phenol Adsorption from Wastewaters].

Science.gov (United States)

Guo, Jun-yuan; Wang, Bin

2016-05-15

In this study, natural zeolite was modified by HDTMA. Effects of the modified conditions, HDTMA-modified zeolite doses, solution pH values, and reaction time on nitro-phenol removal were investigated, and the adsorption kinetics and isotherms were discussed. Compared with natural zeolite, HDTMA-modified zeolite showed better performance in nitro-phenol removal. An adsorption capacity of 2.53 mg · g⁻¹ was achieved when the concentration of HDTMA solution (pH = 10) was 1.2% in preparation of modified zeolite. This adsorption capacity was higher than that obtained by natural zeolite (0.54 mg · g⁻¹). In adsorption tests, when HDTMA- modified zeolite dose was adjusted to 8 g · L⁻¹, the removal efficiency of nitro-phenol reached 93.9% after 90 min reaction, with wastewater pH of 6. Furthermore, the nitro-phenol adsorption process could be well fitted to the pseudo-first-order kinetics model (R² > 0.90), whereas the adsorption isotherm results indicated that Langmuir model provided the best fitting for the equilibrium data at different temperatures, with R² of higher than 0.90.

The application of modified hydrotalcites as chloride scavengers and inhibitor release agents in cement mortars

NARCIS (Netherlands)

Yang, Z.; Fischer, H.; Polder, R.B.

2014-01-01

Owing to the unique molecular structure and high ion exchange capacity, hydrotalcites are believed to have a potential to be modified and tailor-made as an active component of concrete. In this paper, two types of modified hydrotalcites (MHT-pAB and MHT-NO2) were incorporated into cement mortars

Rejecting New Technology: The Case of Genetically Modified Wheat

OpenAIRE

Derek Berwald; Colin A. Carter; Guillaume P. Gruère

2006-01-01

Canada has stringent regulations covering the release of new wheat varieties, but the United States has virtually no regulations in this area. Monsanto Co. developed genetically modified (GM) spring wheat for North America, and made a commitment to the U.S. industry to release this new technology simultaneously in both Canada and the United States, or not at all. The Canadian regulatory bias against new varieties acted as a veto against GM wheat and caused Monsanto to shelve the technology in...

Predominant cerebral cytokine release syndrome in CD19-directed chimeric antigen receptor-modified T cell therapy

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Yongxian Hu

2016-08-01

Full Text Available Abstract Chimeric antigen receptor-modified (CAR T cells targeting CD19 (CART19 have shown therapeutical activities in CD19+ malignancies. However, the etiological nature of neurologic complications remains a conundrum. In our study, the evidence of blood-brain barrier (BBB-penetrating CAR T cells as a culprit was revealed. A patient with acute lymphocytic leukemia developed sustained pyrexia with tremors about 6 h after CART19 infusion, followed by a grade 2 cytokine release syndrome (CRS and neurological symptoms in the next 3 days. Contrast-enhanced magnetic resonance showed signs of intracranial edema. Lumbar puncture on day 5 showed an over 400-mmH2O cerebrospinal pressure. The cerebrospinal fluid (CSF contained 20 WBCs/μL with predominant CD3+ T cells. qPCR analysis for CAR constructs showed 3,032,265 copies/μg DNA in CSF and 988,747 copies/μg DNA in blood. Cytokine levels including IFN-γ and IL-6 in CSF were extremely higher than those in the serum. Methyprednisone was administrated and the symptoms relieved gradually. The predominance of CART19 in CSF and the huge discrepancies in cytokine distributions indicated the development of a cerebral CRS, presumably featured as CSF cytokines largely in situ produced by BBB-penetrating CAR T cells. For the first time, we reported the development of cerebral CRS triggered by BBB-penetrating CAR T cells. Trial registration: ChiCTR-OCC-15007008 .

Role of magnesium oxide and strontium oxide as modifiers in silicate-based bioactive glasses: Effects on thermal behaviour, mechanical properties and in-vitro bioactivity

International Nuclear Information System (INIS)

Bellucci, Devis; Sola, Antonella; Salvatori, Roberta; Anesi, Alexandre; Chiarini, Luigi; Cannillo, Valeria

2017-01-01

The composition of a CaO-rich silicate bioglass (BG-Ca-Mix, in mol%: 2.3 Na 2 O; 2.3 K 2 O; 45.6 CaO; 2.6 P 2 O 5 ; 47.2 SiO 2 ) was modified by replacing a fixed 10 mol% of CaO with MgO or SrO or fifty-fifty MgO-SrO. The thermal behaviour of the modified glasses was accurately evaluated via differential thermal analysis (DTA), heating microscopy and direct sintering tests. The presence of MgO and/or SrO didn't interfere with the thermal stability of the parent glass, since all the new glasses remained completely amorphous after sintering (treatment performed at 753 °C for the glass with MgO; at 750 °C with SrO; at 759 °C with MgO and SrO). The sintered samples achieved good mechanical properties, with a Young's modulus ranging between 57.9 ± 6.7 for the MgO-SrO modified composition and 112.6 ± 8.0 GPa for the MgO-modified one. If immersed in a simulated body fluid (SBF), the modified glasses after sintering retained the strong apatite forming ability of the parent glass, in spite of the presence of MgO and/or SrO. Moreover, the sintered glasses, tested with MLO-Y4 osteocytes by means of a multi-parametrical approach, showed a good bioactivity in vitro, since neither the glasses nor their extracts caused any negative effect on cell viability or any inhibition on cell growth. The best results were achieved by the MgO-modified glasses, both BGMIX-Mg and BGMIX-MgSr, which were able to exert a strong stimulating effect on the cell growth, thus confirming the beneficial effect of MgO on the glass bioactivity. - Highlights: • The composition of a CaO-rich, K 2 O-containing silicate bioglass was modified: • A fixed 10 mol% of CaO was replaced with MgO or SrO or fifty-fifty MgO-SrO. • The sintered glasses showed a strong volume shrinkage with low residual porosity. • The samples showed good mechanical performance and apatite-forming ability in vitro. • The presence of such oxides, especially MgO, improves the samples' bioactivity.

Role of magnesium oxide and strontium oxide as modifiers in silicate-based bioactive glasses: Effects on thermal behaviour, mechanical properties and in-vitro bioactivity

Energy Technology Data Exchange (ETDEWEB)

Bellucci, Devis, E-mail: devis.bellucci@unimore.it [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10, 41125 Modena (Italy); Sola, Antonella [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10, 41125 Modena (Italy); Salvatori, Roberta; Anesi, Alexandre; Chiarini, Luigi [Lab. Biomaterials, Department of Medical and Surgical Sciences of Children & Adults, University of Modena and Reggio Emilia, Via Campi 213/A, 41125 Modena (Italy); Cannillo, Valeria [Department of Engineering “E. Ferrari”, University of Modena and Reggio Emilia, Via P. Vivarelli 10, 41125 Modena (Italy)

2017-03-01

The composition of a CaO-rich silicate bioglass (BG-Ca-Mix, in mol%: 2.3 Na{sub 2}O; 2.3 K{sub 2}O; 45.6 CaO; 2.6 P{sub 2}O{sub 5}; 47.2 SiO{sub 2}) was modified by replacing a fixed 10 mol% of CaO with MgO or SrO or fifty-fifty MgO-SrO. The thermal behaviour of the modified glasses was accurately evaluated via differential thermal analysis (DTA), heating microscopy and direct sintering tests. The presence of MgO and/or SrO didn't interfere with the thermal stability of the parent glass, since all the new glasses remained completely amorphous after sintering (treatment performed at 753 °C for the glass with MgO; at 750 °C with SrO; at 759 °C with MgO and SrO). The sintered samples achieved good mechanical properties, with a Young's modulus ranging between 57.9 ± 6.7 for the MgO-SrO modified composition and 112.6 ± 8.0 GPa for the MgO-modified one. If immersed in a simulated body fluid (SBF), the modified glasses after sintering retained the strong apatite forming ability of the parent glass, in spite of the presence of MgO and/or SrO. Moreover, the sintered glasses, tested with MLO-Y4 osteocytes by means of a multi-parametrical approach, showed a good bioactivity in vitro, since neither the glasses nor their extracts caused any negative effect on cell viability or any inhibition on cell growth. The best results were achieved by the MgO-modified glasses, both BGMIX-Mg and BGMIX-MgSr, which were able to exert a strong stimulating effect on the cell growth, thus confirming the beneficial effect of MgO on the glass bioactivity. - Highlights: • The composition of a CaO-rich, K{sub 2}O-containing silicate bioglass was modified: • A fixed 10 mol% of CaO was replaced with MgO or SrO or fifty-fifty MgO-SrO. • The sintered glasses showed a strong volume shrinkage with low residual porosity. • The samples showed good mechanical performance and apatite-forming ability in vitro. • The presence of such oxides, especially MgO, improves the samples

Controlled drug release from bifunctionalized mesoporous silica

Science.gov (United States)

Xu, Wujun; Gao, Qiang; Xu, Yao; Wu, Dong; Sun, Yuhan; Shen, Wanling; Deng, Feng

2008-10-01

Serial of trimethylsilyl-carboxyl bifunctionalized SBA-15 (TMS/COOH/SBA-15) have been studied as carriers for controlled release of drug famotidine (Famo). To load Famo with large capacity, SBA-15 with high content of carboxyl groups was successfully synthesized by one-pot synthesis under the assistance of KCl. The mesostructure of carboxyl functionalized SBA-15 (COOH/SBA-15) could still be kept even though the content of carboxyl groups was up to 57.2%. Increasing carboxyl content could effectively enhance the loading capacity of Famo. Compared with pure SBA-15, into which Famo could be hardly adsorbed, the largest drug loading capacity of COOH/SBA-15 could achieve 396.9 mg/g. The release of Famo from mesoporous silica was studied in simulated intestine fluid (SIF, pH=7.4). For COOH/SBA-15, the release rate of Famo decreased with narrowing pore size. After grafting TMS groups on the surface of COOH/SBA-15 with hexamethyldisilazane, the release of Famo was greatly delayed with the increasing content of TMS groups.

Immunosuppression Adherence in Stable Kidney Transplant Patients Converted From Immediate- to Prolonged-Release Tacrolimus in Clinical Practice: A Norwegian Study.

Science.gov (United States)

Abedini, Sadollah; Gøransson, Lasse; Cockburn, Elinor; Kilany, Suzanne; Holdaas, Hallvard

2018-02-01

This study investigated medication adherence in kidney transplant patients (KTPs) converted from immediate-release tacrolimus (IR-T) to prolonged-release tacrolimus (PR-T)-based immunosuppression in routine practice. Noninterventional, observational, multicenter study in Norway. Included adult KTPs with stable graft function, converted from IR-T (baseline) to PR-T (1 mg:1 mg) in routine practice. Data were collected at baseline, and months 1, 3, 6, and 12 postconversion. Primary endpoint: adherence using the Basel Assessment of Adherence to Immunosuppressive Medication Scale. Secondary assessments: tacrolimus dose and trough levels (target, 3-7 ng/mL), clinical laboratory parameters (eg, estimated glomerular filtration rate [Modified Diet in Renal Disease]), and adverse events. Ninety-one KTPs (mean ± SD age 47.7 ± 14.3 years) were analyzed. Mean ± SD change in PR-T dose from baseline (4.4 ± 2.4 mg/d) to month 12 was -0.1 ± 0.9 mg/d; mean tacrolimus trough levels remained within target. Overall medication adherence increased from 45.6% at baseline to 58.1% at month 1, but was similar to baseline thereafter; taking and timing adherence followed a similar pattern. Odds ratio (OR) for adherence at month 1 (but not at other time points) was greater versus baseline for overall (OR, 1.71; P = 0.0205), taking (OR, 3.38; P = 0.0004), and timing (OR, 1.77, P = 0.0252) dimensions. Mean ± SD Basel Assessment of Adherence to Immunosuppressive Medication Scale visual analogue scale score at baseline was 96.4 ± 5.5%, and increased postconversion. Estimated glomerular filtration rate remained stable (month 12, 61.6 ± 17.7 mL/min per 1.73 m 2 ), as did other laboratory parameters. Two (2.2%) patients had adverse events considered probably/possibly treatment-related. There was disparity between high, patient-perceived and low, actual adherence. Converting stable KTPs from IR-T to PR-T in routine practice did not impact long-term adherence to immunosuppression; renal

Evaluación comparativa de la liberación in vitro de risperidona 3 mg producida en Cuba contra Risperdal® Comparative assessment of in vitro release of 3 mg Risperidone produced in Cuba versus Risperidal®

Directory of Open Access Journals (Sweden)

Caridad Margarita García Peña

2010-06-01

Full Text Available Se compararon los perfiles de disolución de las tabletas de risperidona 3 mg medicamento genérico producido en Cuba y del Risperdal® (Laboratorios Janssen-Cilag SA, para demostrar su similitud. También se realizó la comparación en varios medios de disolución a diferentes pH para evaluar una posible bioexoneración. Para la cuantificación del principio activo, se utilizó un método por cromatografía líquida de alta resolución, previamente validado. La comparación se realizó sobre la base de los factores de diferenciación y similitud. Los resultados mostraron que no existían diferencias en los perfiles de liberación para las tabletas producidas en Cuba y del producto innovador, así como para los diferentes medios de disolución a los pH utilizados.The 3 mg Risperidone tablets dissolution profiles, a generic drug produced in Cuba and the Risperidal® (Janssen-Cilag S.A. Labs were compared to demonstrate its similarity. Also, we compared some dissolution means at different pH to assess a potential bio-exoneration. To quantify the active principle, a previously validated high-performance liquid chromatography was used. The comparison was conducted on the base of differentiation and similarity factors. Results demonstrated that there weren't differences en release profiles for tablets produced in Cuba and of innovative product, as well as for the different dissolution means at pH used.

In situ characterization of the decomposition behavior of Mg(BH4)2 by X-ray Raman scattering spectroscopy.

Science.gov (United States)

Sahle, Christoph J; Kujawski, Simon; Remhof, Arndt; Yan, Yigang; Stadie, Nicholas P; Al-Zein, Ali; Tolan, Metin; Huotari, Simo; Krisch, Michael; Sternemann, Christian

2016-02-21

We present an in situ study of the thermal decomposition of Mg(BH4)2 in a hydrogen atmosphere of up to 4 bar and up to 500 °C using X-ray Raman scattering spectroscopy at the boron K-edge and the magnesium L2,3-edges. The combination of the fingerprinting analysis of both edges yields detailed quantitative information on the reaction products during decomposition, an issue of crucial importance in determining whether Mg(BH4)2 can be used as a next-generation hydrogen storage material. This work reveals the formation of reaction intermediate(s) at 300 °C, accompanied by a significant hydrogen release without the occurrence of stable boron compounds such as amorphous boron or MgB12H12. At temperatures between 300 °C and 400 °C, further hydrogen release proceeds via the formation of higher boranes and crystalline MgH2. Above 400 °C, decomposition into the constituting elements takes place. Therefore, at moderate temperatures, Mg(BH4)2 is shown to be a promising high-density hydrogen storage material with great potential for reversible energy storage applications.

Drug delivery from hydrophobic-modified mesoporous silicas: Control via modification level and site-selective modification

International Nuclear Information System (INIS)

Tang Qunli; Chen Yuxi; Chen Jianghua; Li Jin; Xu Yao; Wu Dong; Sun Yuhan

2010-01-01

Dimethylsilyl (DMS) modified mesoporous silicas were successfully prepared via co-condensation and post-grafting modification methods. The post-grafting modification was carried out by the reaction of the as-synthesized MCM-41 material (before CTAB removal) with diethoxydimethylsinale (DEDMS). N 2 adsorption-desorption and 29 Si MAS NMR characterization demonstrated that different amount of DMS groups were successfully incorporated into the co-condensation modified samples, and the functional DMS groups were placed selectively on the pore openings and external pore surfaces in the post-grafting modified samples. Subsequently, the controlled drug delivery properties from the resulting DMS-modified mesoporous silicas were investigated in detail. The drug adsorption experiments showed that the adsorption capacities were mainly depended on the content of silanol group (CSG) in the corresponding carriers. The in vitro tests exhibited that the incorporation of DMS groups greatly retarded the ibuprofen release rate. Moreover, the ibuprofen release profiles could be well modulated by varying DMS modification levels and site-selective distribution of functional groups in mesoporous carriers. - The distribution of DMS groups on the pore surfaces of the mesostructures strongly affects the drug release rate. The P-M41-1 and the P-M41-2 possess the close DMS modification levels as the C-M41-10, but the ibuprofen release rates from the P-M41-1 and P-M41-2 are much slower than that from the C-M41-10.

Preliminary assessment of modified borosilicate glasses for chromium and ruthenium immobilization

Energy Technology Data Exchange (ETDEWEB)

Farid, Osama M. [Reactors Department, Nuclear Research Center, Atomic Energy Authority of Egypt, P.O. 13759, Inshas, Cairo (Egypt); Centre of Nuclear Engineering (CNE), Department of Materials, Imperial College London, London, SW7 2BP (United Kingdom); Abdel Rahman, R.O., E-mail: alaarehab@yahoo.com [Hot Laboratory Center, Atomic Energy Authority of Egypt, P.O. 13759, Inshas, Cairo (Egypt)

2017-01-15

The feasibility of using modified alkali borosilicate glasses for ruthenium and chromium immobilization is preliminary assessed by investigating the immobilization system structure under normal conditions. Within this context, reference alkali borosilicate, and simulated Magnox-modified glasses were prepared and studied. The results indicate that ruthenium is immobilized in the vitreous structure as encapsulated RuO{sub 2} crystallites that act as seeds for heterogeneous nucleation of other crystalline phases. The presence of Zn, as modifier, has contributed to chromium immobilization in zincochromite spinel structure, whereas Ca is accommodated in the vitreous structure. Immobilization performance was evaluated by conducting conservative static leach test and studying the leached glass. Leached glass morphology was altered, where near surface reference glass is leached over 400 nm and simulated Magnox-modified sample is altered over 300 nm. Normalized release rates are within normal range for borosilicate material. For simulated Magnox-modified sample, Ca and alkali structural element, i.e. Na and Li, are leached via ion-exchange reaction. The ion-exchanged fraction equals 1.06 × 10{sup −8} mol/m{sup 2} s and chromium has slightly lower normalized release rate value than ruthenium. - Highlights: • The presence of modifiers and waste oxides led to localized de-vitrification. • Ruthenium is encapsulated within the vitreous glass network as RuO{sub 2} crystals. • Chromium is immobilized within the zincochromite spinel structure. • Pitting and cracks induced by leaching did not affect the immobilization performance.

Characterization of polymer-modified cement as a solidification agent for the radwaste

International Nuclear Information System (INIS)

Ji, Young-Yong; Kwak, Kyung-Kil; Hong, Dae-Seok; Ryu, Woo-Seog

2012-01-01

Highlights: ► Polymer-modified cement (PMC) by modification with water-based resins. ► Determination of the optimized polymer content. ► Evaluation of the improved chemical resistance of the PMC. ► Decrease of the amount of ions released into the demineralized water. ► Highly improved property for the nuclide diffusivity at the Co-60. - Abstract: Polymer-modified cement can be produced by partially replacing cement hydrate binders in ordinary Portland cement with polymeric compounds. It is known that the addition of the polymer to the cement paste leads to improved quality, which would be expected to have a high chemical resistance. In order to investigate the application as a solidification agent for the radwaste, polymer-modified cement specimens, by modification with water-based resins, were prepared according to the polymer content from 0% to 30%. The optimized polymer content in the cement pastes was then determined through the compressive strength and the porosity test. Finally, the improved chemical resistance of the polymer-modified cement with the optimized polymer content was evaluated by the thermal cycling, the immersion, and the leaching tests. From the test results, the amount of ions released into the water showed lower values of about 20% at the polymer-modified cement. Especially, a highly improved nuclide diffusivity of Co-60 was observed in the polymer-modified cement.

Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

International Nuclear Information System (INIS)

Shen, Shou-Cang; Ng, Wai Kiong; Chia, Leonard; Dong, Yuan-Cai; Tan, Reginald B.H.

2011-01-01

Graphical abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by rapid sonochemical co-condensation to achieve high capability for protein immobilization. Highlights: → Amino-modified monodispersed silica nanoparticles were synthesized by rapid co-condensation. → Strong positive charge was created by aminopropyl-modification. → Capability for immobilization of negatively charged protein was enhanced. → Electrostatic interaction between proteins and surface contributed to the enhanced adsorption. -- Abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by 13 C and 29 Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.

Sonochemical synthesis of (3-aminopropyl)triethoxysilane-modified monodispersed silica nanoparticles for protein immobilization

Energy Technology Data Exchange (ETDEWEB)

Shen, Shou-Cang, E-mail: shen_shoucang@ices.a-star.edu.sg [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Ng, Wai Kiong; Chia, Leonard; Dong, Yuan-Cai [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Tan, Reginald B.H., E-mail: reginald_tan@ices.a-star.edu.sg [Institute of Chemical and Engineering Sciences, A-STAR (Agency for Science, Technology and Research), 1 Pesek Road, Jurong Island, Singapore 627833 (Singapore); Department of Chemical and Biomolecular Engineering, The National University of Singapore, 4 Engineering Drive 4, Singapore 117576 (Singapore)

2011-10-15

Graphical abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by rapid sonochemical co-condensation to achieve high capability for protein immobilization. Highlights: {yields} Amino-modified monodispersed silica nanoparticles were synthesized by rapid co-condensation. {yields} Strong positive charge was created by aminopropyl-modification. {yields} Capability for immobilization of negatively charged protein was enhanced. {yields} Electrostatic interaction between proteins and surface contributed to the enhanced adsorption. -- Abstract: 3-Aminopropyltriethoxysilane modified monodispersed silica nanoparticles were synthesized by a rapid sonochemical co-condensation synthesis procedure. The chemical nature of surface organic modifier on the obtained modified silica nanoparticle was characterized by {sup 13}C and {sup 29}Si MAS Nuclear Magnetic Resonance (NMR) spectroscopies, Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA)- differential scanning calorimetry (DSC). Due to the strengthened positive surface charge of the silica nanoparticles by the modification with aminopropyl groups, the capability for bovine serum albumin (BSA) adsorption was significantly increased as compared with bare silica nanoparticles. 80 mg/g BSA was adsorbed on modified silica nanoparticles, whereas only 20 mg/g BSA could be loaded on pure silica nanoparticles. The enhanced positive surface charge repelled proteins with net positive charge and the modified silica nanoparticles exhibited negligible adsorption of lysozyme, thus a selective adsorption of proteins could be achieved.

Investigation of properties of modified oxides structured by nano technology

International Nuclear Information System (INIS)

Kurina, I.S.; Serebrennikova, O.V.; Rumyantsev, V.N.; Dvoryashin, A.M.

2009-01-01

Research results on the PuO 2 +MgO fuel composition with CeO 2 as a PuO 2 simulator are presented. The water nano technology for the production of oxide ceramic materials, developed in IPPE, was used for fabrication of powders and modified pellets. This technology includes obtaining precipitate, consisting of particles of different sizes as well as of nanoparticles, which is further calcined, pressed and sintered. It results in modifying structure of the sintered pellets. Modified pellets have anomalously high thermal conductivity measured by the axial heat flux method [ru

X-ray absorption study at the Mg and O K edges of ultrathin MgO epilayers on Ag(001)

International Nuclear Information System (INIS)

Luches, P.; D'Addato, S.; Valeri, S.; Groppo, E.; Prestipino, C.; Lamberti, C.; Boscherini, F.

2004-01-01

We determined the local atomic structure of MgO epilayers on Ag(001) by means of polarization-dependent x-ray absorption spectroscopy measurements at the Mg and O K edges. A quantitative analysis of the data in the extended energy range has been performed using multiple scattering simulations. We found that, even in the ultrathin limit, the local structure of the films is rocksalt and we obtained a quantitative evaluation of the average in-plane and out-of-plane film strain at the different thicknesses investigated. An in-plane compressive strain, due to lattice mismatch with the Ag substrate, is clearly present for the 3 ML film. The out-of-plane lattice constant is found to be expanded, in agreement with the expected behavior for a tetragonal distortion of the unit cell. This growth-induced strain is gradually released with increasing thickness and it is almost completely relaxed at 20 ML. Any significant intermixing with the Ag substrate can be ruled out. An expansion of the interplanar distance at the MgO-Ag interface is detected and its sign and magnitude are found to be in agreement with recent ab initio simulations. This work provides previously unavailable input for modeling the physical properties of the system and supports the hypothesis that the different electronic properties of MgO films on Ag(001) are not related to structural or compositional differences at the ultrathin limit

Effective Anti-miRNA Oligonucleotides Show High Releasing Rate of MicroRNA from RNA-Induced Silencing Complex.

Science.gov (United States)

Ariyoshi, Jumpei; Matsuyama, Yohei; Kobori, Akio; Murakami, Akira; Sugiyama, Hiroshi; Yamayoshi, Asako

2017-10-01

MicroRNAs (miRNAs) regulate gene expression by forming RNA-induced silencing complexes (RISCs) and have been considered as promising therapeutic targets. MiRNA is an essential component of RISC for the modulation of gene expression. Therefore, the release of miRNA from RISC is considered as an effective method for the inhibition of miRNA functions. In our previous study, we reported that anti-miRNA oligonucleotides (AMOs), which are composed of the 2'-O-methyl (2'-OMe) RNA, could induce the release of miRNA from RISC. However, the mechanisms underlying the miRNA-releasing effects of chemically modified AMOs, which are conventionally used as anti-cancer drugs, are still unclear. In this study, we investigated the relationship between the miRNA releasing rate from RISC and the inhibitory effect on RISC activity (IC 50 ) using conventional chemically modified AMOs. We demonstrated that the miRNA-releasing effects of AMOs are directly proportional to the IC 50 values, and AMOs, which have an ability to promote the release of miRNA from RISC, can effectively inhibit RISC activity in living cells.

In vitro evaluation of extemporaneously compounded slow-release capsules containing morphine sulfate or oxycodone hydrochloride.

Science.gov (United States)

Glowiak, Dana L; Green, Julie L; Bowman, Bill J

2005-01-01

The in vitro performance of extemporaneously compounded morphine sulfate and oxycodone hydrochloride slow-release capsules was evaluated. Capsules containing varying amoutns of morphine sulfate (15, 60, 200 mg) or oxycodone hydrochloride (10, 80, 200 mg) were prepared and provided by a Phoenix, Arizona, pharmacy. The capsules also contained 40% Methocel E4M Premium to slow the release of their active ingredient and sufficient lactose to fill the capsules. Three batches of each capsule strength were prepared, and replicates from each batch were evlauated using United Stated Pharmacopeia dissolution apparatus II. Samples were taken at regular time intervals over 24 hours. After 1 hour the pH of the dissolution medium was adjusted form 1.2 to 4.0, and after 2 hours the pH was adjusted to 6.8. The amount of drug released at each time point was determined spectrophotometrically. The compounded capsules released 14% to 23%, 67% to 85% and 93% to 98% of their active ingredient after 0.5, 4 and 12 hours, respectively. The relative standard deviations between the replicates from each batch were less than 10% for most time points. The percent of drug released over the first 4 hours was linear (r squared = 0.9409-0.9999) when plotted versus time 1/2, indicating adherence to the simplified Higuchi model. Statistical analysis of the Higuchi dissolution constants indicated a significant difference (P less than 0.05) between batch No.3 and the other two batches of 200-mg oxycodone hydrochloride capsules. There was also a statistical difference between most of the Higuchi dissolution constants for the different-strength slow-release capsules and most slow-release capsules and equivalent strength controlled-release manufactured tablets (P less than 0.05). Using 40% Methocel E4M Premium slowed the release of morphine sulfate and oxycodone hydrochloride from extemporaneously compounded capsules. The in vitro performance of the slow-release capsules showed little intrabatch variation

Experimental data for aluminum removal from aqueous solution by raw and iron-modified granular activated carbon

Directory of Open Access Journals (Sweden)

Mokhtar Mahdavi

2018-04-01

Full Text Available This dataset deals with the modification of granular activated carbon (GAC with FeCl3 under basic conditions (pH ≈ 12 for removal of aluminium (Al from aqueous solution. The structural properties and operational parameters including Al ion concentration (2.15 and 10.3 mg/L, pH solution (2–10, adsorbent dosage (0.1–5 g/L, and contact time (0–10 h was investigated for raw and modified GAC. This dataset provides information about Al removal by GAC and modified GAC at conditions including: pH = 8, contact time = 6 h, initial Al concentration = 2.15 mg/L. The characterization data of the adsorbents was analysed by Fourier transform infrared (FTIR spectroscopy, scanning electron microscopy (SEM and Brunauer, Emmett and Teller (BET test. The data showed that Freundlich isotherm with and Pseudo second order kinetic model were the best models for describing the Al adsorption reactions. The acquired data indicated that the maximum adsorption capacity of GAC and modified GAC to uptake Al (C0 = 10.3 mg/L was 3 and 4.37 mg/g respectively. Keywords: Aluminium removal, Adsorption, Iron-modified GAC, Water treatment

Waste isolation pilot plant performance assessment: Radionuclide release sensitivity to diminished brine and gas flows to/from transuranic waste disposal areas

Energy Technology Data Exchange (ETDEWEB)

Day, Brad A.; Camphouse, R. C.; Zeitler, Todd R. [Sandia National Laboratories, Carlsbad (United States)

2017-03-15

Waste Isolation Pilot Plant repository releases are evaluated through the application of modified parameters to simulate accelerated creep closure, include capillary pressure effects on relative permeability, and increase brine and gas saturation in the operations and experimental (OPS/EXP) areas. The modifications to the repository model result in increased pressures and decreased brine saturations in waste areas and increased pressures and brine saturations in the OPS/EXP areas. Brine flows up the borehole during a hypothetical drilling intrusion are nearly identical and brine flows up the shaft are decreased. The modified parameters essentially halt the flow of gas from the southern waste areas to the northern nonwaste areas, except as transported through the marker beds and anhydrite layers. The combination of slightly increased waste region pressures and very slightly decreased brine saturations result in a modest increase in spallings and no significant effect on direct brine releases, with total releases from the Culebra and cutting and caving releases unaffected. Overall, the effects on total high-probability mean releases from the repository are insignificant, with total low-probability mean releases minimally increased. It is concluded that the modified OPS/EXP area parameters have an insignificant effect on the prediction of total releases.