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In the present work, Doxycycline loaded gum acacia (GA)/poly(sodium acrylate) (SA) hydrogels were prepared for the oral drug delivery of model drug Doxycycline. The hydrogels were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FTIR) scanning electron microscopy (SEM) and Zeta potential. The dynamic release of Doxycycline was investigated in the physiological fluids at 37 °C. Various kinetic models such as Power function model, Schott model and Higuchi model were applied to interpret the release data. Schott model was found to be most fitted. The Doxycycline loaded hydrogels were tested for their antibacterial action against E. coli .

In this study, glyoxal-cross-linked Iota carrageenan (IC) /poly(vinyl alcohol) PVA films were prepared and loaded with silver nanoparticles via a green approach, consisting of sweet lime juice indu...

In this work, calcium alginate hydrogels have been prepared by a new technique, called ‘diffusion through dialysis tube’ (DTDT) which involved transfer of crosslinking ions into alginate solution via a dialysis tube with a molecular weight cutoff of 8 k Da. The various hydrogels, prepared with varying degree of crosslinking, were characterized by FTIR, XRD and TG analysis. We also investigated their dynamic water absorbency in phosphate buffer saline (PBS) of pH 7.4 and the data were interpreted in terms of various kinetic models. The equilibrium water uptake data was used to determine network parameters of hydrogels. Finally, the stability and water absorbency of these hydrogels were enhanced to a desired level by using crosslinker solutions, composed of Ba++/Ca ++and Zn++ / Ca++ ions.

In this work, plain and model therapeutic protein Bovine Serum Albumin(BSA) loaded alginate hydrogels, crosslinked with Ca(II)+Ba(II) ions, were prepared by ‘Diffusion Through Dialysis Tube’ (DTDT) technique which involved permeation of crosslinking ions into alginate solution via a dialysis tube with a molecular weight cutoff of 8 k Da. The model protein BSA loaded hydrogels were characterized by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) analysis. The dynamic water uptake behavior of plain hydrogels was investigated in phosphate buffer saline (PBS) of pH 7.4 at 37 °C. Finally, the controlled release of therapeutic protein BSA from these hydrogels was studied in the phosphate buffer medium of pH 7.4 at 37 °C.The release data were interpreted in the terms of Power function model and First order kinetic model respectively.

In the present work, AgNPs loaded chitosan/poly(acrylamide-co-itaconic acid) inter-polyelectrolyte complex (IPC) films have been prepared for antimicrobial applications. The AgNPs-loaded IPC films have been characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Transmission electron microscopy (TEM), Scanning electron microscopy (SEM), Thermogravimetric analysis (TGA) and Surface plasmon resonance (SPR). Particle size of synthesized AgNPs was found to be in the range 10-30nm. These films exhibited a remarkable antibacterial property against strong pathogen E.Coli, thus offering their candidature for antimicrobial applications.

A spiking neural system (SNN) demonstrates is utilized to distinguish characters in a character set. The framework is a two layered structure involving consolidate and-fire and dynamic dendrite neurons. There is both excitatory and inhibitory relationship in the framework. It is discovered that the vast majority of the characters are perceived in a character set comprising of 26 letters in order characters. Spiking Neural Network genuinely mimics the acknowledgment ability like a human cerebrum natural occasion. This paper features the adequacy of sensible conduct of insight in a more reasonable manner and energy to perceive for time related slipped by occasions is conceivable just in SNN displaying

With an aim to develop chitosan film with controllable swelling behavior and maximum antimicrobial efficacy, we hereby report cellulose nano crystals loaded chitosan films with Curcumin/Ag nano particles embedded as strong antimicrobial agents. The CNC had average size of 40-90nm with poly dispersity index of 3.641. The TEM analysis of Ag NPs, produced via DMF reduction, revealed a particle size range of 15-25nm. The Surface Plasmon resonance (SPR) of these Ag NPs shifted from 380 to 440nm, with the increase in concentration of Ag (I). The TGA of the film samples Ch/CNC, and Ch/CNC (Ag463/Cur450) exhibited% weight loss of around 95 and 80 respectively, thus indicating higher stability due to presence of Ag NPs. In XRD analysis 2θ reflections at 38.12, 44.28 and 66.46°, confirmed the presence planes (1 1), (2 0) and (2 0) respectively. In skin irritation test, the mean Erythema scores observed after 72h was zero for both the Curcumin and Ag NPs/Curcumin loaded films. The percent wound reduction, observed for the film samples Ch/CNC (Cur450) and Ch/CNC (Ag NP463/Cur450) was 57.8 and 97.2 respectively, indicating better suitability of Ag NPs/Curcumin loaded film.

Cotton fabric with improved antibacterial properties is always invited for effective use in wound dressing and healing applications. In this study, poly( N-isopropyl acrylamide) network has been produced in situ in porous cotton cellulose fabric by photo polymerization using UV-radiation. The thermoresponsiveness of the resulting fabric has been used to entrap silver nanoparticles with the fabric. The presence of silver nanoparticles in the fabric has been characterized by X-ray diffraction, transmission electron microscopy, and dynamic light scattering analysis. The fabrics have been found to possess fair mechanical properties. The individual and aggregation particle size of the silver nanoparticles was found to be in the range 13–20 nm and 140–220 nm. This aggregation phenomenon was also confirmed by dynamic light scattering measurement, i.e. 256 nm. The silver nanoparticles exhibits polydispersity index 0.18 and zeta potential −2.86 mV. The fabric exhibited fair biocidal action against Escherichia coli and Staphylococcus aureus, thus indicating its possible utility in medicinal application.

In the present work, antibiotic drug gentamicin sulfate (GS) has been loaded into alginate dialdehyde-crosslinked casein (CAS) films for wound dressing applications. The films have been characterized by Fourier transform infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy. The dynamic release of model drug GS has been investigated in the physiological fluid at 37 °C. The drug release data has been interpreted in the terms of various kinetic models such as Power function model, first order model and Schott model. The release data was found to be well fitted by Schott model. The various diffusion coefficients are also evaluated. The adsorption of model therapeutic protein BSA on the film has been investigated. The maximum adsorption is found to be 5.7 mg/cm2.The films were tested for their antibacterial and anti-fungal action. Finally, the in vivo wound healing study was carried out on Albino wistar rats.

In this work, free-radical aqueous polymerization of acrylic acid (AAc) was carried-out in cellulose solution(dissolved in NaOH/urea system) followed by equilibration in ammonium sulfate solution to yield Regenerated Cellulose-Poly-acrylic acid (RC-PAAc) hydrogels .The water absorbency of these gels was investigated as a function of concentration of cellulose, acrylic acid and cross-linker N,N’methylene bis-acrylamide. A negative concentration dependence of water uptake was observed. The gels were loaded with silver nitrate solution followed by borohydride reduction to yield silver nano particles loaded hydrogels. These gels were characterized by TGA, and TEM analysis. Finally the silver nano particles loaded gels demonstrated fair antibacterial activity against E.coli as model bacteria.

In the present study, calcium alginate-impregnated cotton fabric has been loaded with copper nanoparticles to impart antimicrobial properties. The fabric, so prepared, has been characterized by TEM and FTIR analysis. There has been no adverse effect found on the mechanical properties of fabric due to alginate impregnation. The release of Cu(II) ions has been studied in the physiological fluid at 37°C under different experimental conditions, such as varying concentrations of sodium alginate and the crosslinker calcium chloride. The fabrics showed an appreciable release of Cu(II) ions, extended over a period of 50 h. The amount of Cu(II) ions released showed a negative dependence on the amount of alginate present within the fabric network and the concentration of crosslinker calcium chloride used. The release data was fitted on the Higuchi diffusion-controlled release model successfully. Finally, the antibacterial activity of fabric was tested by zone inhibition method against E. coli as model bacteria. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

This paper investigates the curing of biodegradable polymer films which were synthesized from soybean oil through the ultraviolet radiation and their stability against thermal degradation. In this study the epoxidation of soybean oil has been carried out via peracetic method. Further, an epoxy acrylate resin was synthesized from the epoxidized soybean oil (ESO) by using acrylic acid monomer. Triethylamine (TEA) and hydroquinone were used as a catalyst and inhibitor respectively. The acrylation of epoxidized soybean oil (AESO) is done by introducing acrylic acid, which is an unsaturated monomer into oxirane groups of the epoxidized oil (ESO). This reaction was confirmed by analytical data in terms of oxirane oxygen content, acid value, viscosity and spectral analysis. Different UV curable formulations have been investigated using synthesized acrylated resin and trifunctional acrylate monomer used as crosslinkable active diluents with photoinitiator. Monomer used was trimethylolpropane trimethacrylate (TMPTMA) while photoinitiator used was benzophenone along with an activator dimethyl ethanol amine (DEA). The mixtures were cured to make thin polymeric films under UV radiation with optimum irradiation dosing time of 20 min to produce the excellent cured coating which exhibits good thermal stability of about 473 K.

In this work, the temperature-dependent swelling and shrinking behavior of poly(N-isopropyl acrylamide) has been exploited for in situ formation of silver nanoparticles within the hydrogel network. The polymer–silver nanoparticle composite has been characterized by FT-IR, XRD and TEM analysis. The silver nanoparticles exhibited an average diameter of 20 nm. The silver nanoparticles/poly(N-isopropyl acrylamide) (AgNPs/PNIPAM) composite demonstrated fair antibacterial action against Escherichia coli.

This work involves chemical modification of cotton fabrics by natural, biocompatible, and biodegradable polysaccharide — chitosan — followed by incorporating silver nanoparticles in the fabrics. The excellent chelating property of chitosan binds the silver metal ions that are later on reduced to nanoparticles giving rise to chitosan-attached nanosilver-loaded fabrics. The silver nanoparticles-loaded chitosan-attached fabric has been characterized by surface plasmon resonance, transmission electron microscopy, energy dispersive X-ray analysis, and X-ray diffraction analysis. These chitosan-attached nanosilver-loaded fabrics exhibit excellent antibacterial action against model bacteria E. coli.

Purpose – The purpose of this paper is to develop a novel organic‐inorganic (epoxy‐silicone) hybrid resin for application in heat resistant surface coatings.Design/methodology/approach – Thermally stable aminosilicone resin was prepared by using diethoxydimethyl silane and γ‐aminopropyldiethoxy methyl silane.Findings – The hybrid epoxy silicone resin shows significant properties such as toughness, chemical resistance and thermal stability.Research limitations/implications – The prepared amino siloxane was cured by commercially available epoxy resin PG 100 and toluene diisocyanate in different ratios at high as well as at room temperature to develop high‐temperature vulcanisation and room temperature vulcanisation resin systems.Practical implications – The hybrid epoxy silicone resin may be used as heat resistant coatings due to their low shrinkage and lesser internal stress.Originality/value – The developed hybrid epoxy silicone resin was novel for application in thermally stable coatings.

In this study cyclodextrin (CD) has been grafted onto cellulose back-bone of cotton fabric using citric acid as crosslinker. The CD-grafted fabric was characterized by SEM and FTIR analysis. The percent grafting of CD on fabric has been found to increase with concentration of CD, citric acid, and sodium dihydrogen phosphate. The CD-grafted fabric has been loaded with silver(I) ions for the purpose of obtaining a slow release device. The Ag(I) loaded grafted fabric showed fair antibacterial properties against E. Coli. The release of Ag(I) ions from the CD-grafted fabric was observed for a period of seven days.

SummaryUlcerative colitis (UC) and Crohn's disease (CD) are considered to be immunologically mediated disorders that share certain features with murine models of colitis. Whether any of these models are physiologically relevant to the human condition remains controversial. The hypothesis is that increased amounts of antibodies neutralizing transforming growth factor (TGF)-β, interleukin (IL)-2 or IL-10 create a relative immunodeficient state in inflammatory bowel disease (IBD) that predisposes to disease. To evaluate this, serum samples from patients with UC or CD and from normal healthy individuals were studied by enzyme-linked immunosorbent assays. Antibodies recognizing TGF-β were most prevalent in UC (P

In recent past magnetic nanoparticles have been explored for a number of biomedical applications due to their superparamagnetic moment with high magnetic saturation value. For these biomedical applications, magnetic nanoparticles require being monodispersed so that the individual nanoparticle has almost identical physico-chemical properties for biodistribution, bioelimination and contrast imaging potential. Further, the surface functionalization/modification of magnetic nanoparticles ultimately facilitate the protein or DNA separation, detection and magnetic resonance imaging contrast, drug delivery and hyperthermia applications. The essential goal of this review is to evaluate the recent advances of magnetic nanoparticles for tumor, brain targeting and hyperthermia applications.

Graft co‐polymerization of monomers acrylamide (AAm) and itaconic acid (IA) on to cotton fabric has been carried out in aqueous medium using ceric ammonium nitrate as initiator under the catalytic activity of nitric acid. The cotton fabric was optimally initiated in 20 mM aqueous solution of initiator for 15 min, followed by its immersion in aqueous solution containing of monomers AAm and IA, and cross‐linker N,N′‐methylene bisacrylamide (MB)at 30°C. To obtain optimum conditions, the percent grafting was investigated as a function of concentration of the monomers, the cross‐linker and the initiator, reaction temperature and time of immersion for initiation. The grafted cotton fabric was also investigated for its water uptake behavior.

The incorporation of metal nanoparticles into polymers has resulted in the origination of a new class of materials that have found fascinating interest in biomedical, catalytic, optical and electronic as well as quantum‐size domain applications. This review article describes different strategies that have been adopted for the synthesis of metal nanocomposite materials with polymers and gel macromolecules (hydrogels and nanogels).

Superabsorbent poly(methacrylic acid-co-partially neutralized acrylic acid) hydrogels have been prepared by inverse suspension polymerization, using SPAN 80 as dispersant, heptane as the organic phase, N,N′-methylene bisacrylamide as the cross-linker and potassium persulphate as initiator. The water uptake behavior has been analyzed as a function of amount of cross-linker, concentration of dispersant, stirring rate, synthesis temperature and particle size of gels. Their swelling behavior was also studied in salt solutions, Various types of diffusion coefficients and activation energy for swelling process were also evaluated.

In this work, aqueous solutions of chitosan (Ch) and [poly(acrylamide(AAm)-co-itaconicacid(IA)] have been mixed to yield Ch/poly(AAm-co-IA) Inter-polyelectrolyte complex (IPC) films. The films were characterized by FTIR, X-ray diffraction (XRD) and thermo gravimetric analysis (TGA). There was remarkable increase in the crystalline nature of IPC films. The films were investigated for their water absorption capacity in the physiological fluid (PF) of pH 7.4 at 37 °C. The amount of IA present in the film forming solutions affected the water absorption behavior of the resulting films. The dynamic water uptake data were interpreted by various kinetic models. The effect of pH on the swelling ratio (SR) indicated that the films showed highest swelling in lower as well as higher pH media. The water vapor transmission rates (WVTR) were obtained in the range of 6000-6645 g/m(2)/day.

Fast‐swelling micrometer sized superabsorbents were synthesized through a rapid solution polymerization of n‐vinyl‐2‐pyrrolidone (NVP) and partially neutralized acrylic acid (PNAAc) under normal atmospheric conditions using N,N'‐methylene bisacrylamide (MB) as crosslinker and sodium bicarbonate as porogen. The effect of various parameters such as crosslinker concentration, degree of neutralization of monomer acid, concentration of initiator have been evaluated. Water retention capacity of superabsorbents under varying loads was also examined. The drying behavior of polymers at 37°C was also studied. The gels showed sharp volume transition in solutions of divalent metal ions. The superabsorbents were also characterized by FTIR and TGA.

The present study describes the water uptake behavior and mechanical properties of superporous hydrogels prepared through rapid copolymerization of acrylamide and acrylic acid in the presence of NaHCO3 used as porogen. The formation of pores has been confirmed by SEM analysis. The increase in concentration of porogen from 23.8×10−2 mM to 71.4×10−2 mM caused enhancement in the equilibrium water uptake from 1068±48 to 8087±112 percent. Likewise, the variation in crosslinker content from 64.8×10−3 mM to 194.5×10−3 mM caused the percent water uptake to decrease from 9237±123 to 2758±61 in distilled water. For 9.71 mM of acrylic acid the equilibrium water uptake was found to be maximum (i.e., 10733±168) and it decreased above and below this optimum value. The gelation time varied appreciably with crosslinker and monomer acid concentrations in the gelation mixture. The water uptake of superporous gel decreased sharply when an equilibrated sample was put in NiCl2 solutions of different concentrations. However, N...

Amine oxides are amine-based surfactants, represent one of the smaller classes of surfactants as compared to alcohol ethoxylates and sulfonated and sulfated anionic surfactants. However, the uniqueness of the hydrophile in such surfactants provides specific properties that are difficult, if not impossible, to replicate by the use of classic nonionic and anionic surfactants. The aim of the present paper is to survey the most important developments and understandings of the chemistry of amine oxide production, it’s physico-chemical studies, applications and environmental properties.

Disturbance is an inherent part of any power system during the transition from one steady-state operating condition to the next. Protective relays may experience abnormal operating conditions during this transient period. This paper reviews various control actions that play a part during the transition and provides technical guidance to the industry on the application and setting of generator protective relays that can operate during major system disturbances.

Inflammation of the female reproductive tract increases susceptibility to HIV-1 and other viral infections and, thus, it becomes a serious liability for vaginal products. Excessive release of proinflammatory cytokines may alter the mucosal balance between tissue destruction and repair and be linked to enhanced penetration and replication of viral pathogens upon chemical insult. The present study evaluates four surface-active microbicide candidates, nonoxynol-9 (N-9), benzalkonium chloride (BZK), sodium dodecyl sulfate, and sodium monolaurate for their activity against human sperm and HIV, and their capacity to induce an inflammatory response on human vaginal epithelial cells and by the rabbit vaginal mucosa. Spermicidal and virucidal evaluations ranked N-9 as the most potent compound but were unable to predict the impact of the compounds on vaginal cell viability. Interleukin (IL)-1 release in vitro reflected their cytotoxicity profiles more accurately. Furthermore, IL-1 concentrations in vaginal washings correlated with cumulative mucosal irritation scores after single and multiple applications (P < 0.01), showing BZK as the most damaging agent for the vaginal mucosa. BZK induced rapid cell death, IL-1 release, and IL-6 secretion. The other compounds required either more prolonged or repeated contact with the vaginal epithelium to induce a significant inflammatory reaction. Increased IL-8 levels after multiple applications in vivo identified compounds with the highest cumulative mucosal toxicity (P < 0.01). In conclusion, IL-1, IL-6, and IL-8 in the vaginal secretions are sensitive indicators of compound-induced mucosal toxicity. The described evaluation system is a valuable tool in identifying novel vaginal contraceptive microbicides, selecting out candidates that may enhance, rather than decrease, HIV transmission.

UV curable systems have found wide applications in clear coatings. However, coatings containing pigment showed a degree of curing inhibition due to the absorption, scattering and reflection of the UV radiation caused by the presence of pigments in the coating film. This results in poor through‐cure and consequently in poor adhesion. Thus, pigments used in the UV curable coating systems should not absorb radiation in the same region as the photo‐initiators. One of the solutions to such a problem, reported in this paper, was to develop more reactive, alcohol soluble, non‐heat reactive, low molecular weight cresol based, pigmented novolac epoxy acrylate systems, which have a lower absorption in the UV region. In addition, the effects of several photoinitiators having absorption in the longer wavelength region of the UV spectrum were investigated.

Hard gelatin capsules, containing riboflavin-loaded poly (N-viny1–2-pyrrolidone)-polyacrylamide cylindrical hydrogels, were modified chemically by treating with an aqueous formaldehyde solution for the purpose of delayed release of drug along the gastrointestinal tract. The tdis (disintegration time) of capsules was studied as a function of concentration of formaldehyde solution and the treatment time. The dynamic release of vitamin B2 was studied as a function of crosslinking ratio of the hydrogels. The device studied seems to have potential to be used for colon-targeted drug delivery. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2277–2282, 2003

Tyrosine phosphorylation has recently been associated with capacitation and suggested as a regulator of sperm movement, especially characterizing hyperactivation. The objective of this study was to verify if tyrosine phosphorylation of human sperm proteins was essentially required for the maintenance of motility as well as the development of hyperactivation. Washed sperm were incubated for 6 h in Ham's F10 + 0.35% HSA at 37 degrees C in 5% CO(2), with and without the tyrosine kinase inhibitors genistein, tyrphostin, erbstatin, or herbimycin A and the wide-spectrum kinase inhibitor staurosporin. The concentrations of the inhibitors used in the experiments did not induce sperm toxicity, as measured by membrane integrity and mitochondrial function assays. Samples incubated without the inhibitors (control), increased their tyrosine kinase activity (ELISA), the number and intensity of tyrosine-phosphorylated (PY) protein bands (Western blot), the incidence of PY-immunoreactive sperm (immunofluorescence), and some of the sperm motion characteristics (CASA), such as velocity (VEL), amplitude of lateral head displacement (ALH), and hyperactivation. Among the selective protein tyrosine kinase inhibitors, genistein was the most active and consistent, inhibiting sperm tyrosine kinase activity, PY proteins, incidence of PY sperm, and sperm motility and motion parameters, such as VEL, ALH, and hyperactivation. The rest of the kinase inhibitors decreased motion characteristics to a varied extent and had different effects on phosphorylation parameters. In general, they decreased PY phosphorylation of 2 proteins (83 and 54 kDa) present in whole sperm extracts, and two sets of proteins of low (39-49 kDa) and medium (55-87 kDa) molecular weight present in the Triton X-100-solubilized sperm protein fraction. This inhibition was evident regardless of the total tyrosine kinase activity of the samples or the incidence of PY-immunoreactive sperm. The described findings further support the association between motility and protein tyrosine phosphorylation in human sperm and point to certain proteins as the main linkers.

Hydrogels, composed of poly(acrylamide-co-maleic acid) were synthesized and the release of vitamin B2 from these gels was studied as a function of the pH of the external media, the initial amount of the drug loaded, and the crosslinking ratio in the polymer matrix. The gels containing 3.8 mg of the drug per gram gel exhibit almost zero-order release behavior in the external media of pH 7.4 over the time interval of more than their half-life period (t1/2). The amount of the drug loaded into the hydrogel also affected the dynamic release of the encapsulated drug. As expected, the gels showed a complete swelling-dependent mechanism, which was further supported by the similar morphology of the swelling and release profiles of the drug-loaded sample. The hydrophilic nature of the drug riboflavin does not contribute toward the zero-order release dynamics of the hydrogel system. On the other hand, the swelling osmotic pressure developed between the gels and the external phase, due to loading of the drug by equilibration of the gels in the alkaline drug solution, plays an effective role in governing the swelling and release profiles. Finally, the minimum release of the drug in the swelling media of pH 2.0 and the maximum release with zero-order kinetics in the medium of pH 7.4 suggest that the proposed drug-delivery devices have a significant potential to be used as an oral drug-delivery system for colon-specific delivery along the gastrointestinal (GI) tract. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1133–1145, 2002; DOI 10.1002/app.10402

This paper is based on a report of the same title, prepared by Working Group K3 of the Substation Protection Subcommittee of the Power System Relaying Committee of the Power Engineering Society of the IEEE. The paper begins with background information on the causes, measurement techniques, and consequences of overheating in mineral-oil-immersed power transformers. Then techniques for adaptive transformer thermal overload protection based on the real-time solution of the transient heating equations are presented. An adaptive overcurrent protection implementation, and the related functional requirements, are discussed. The equations of Clause 7 of the 1995 IEEE Guide for Loading Mineral-Oil-Immersed Transformers are used in the analysis, with a slight modification to allow for continuously varying ambient temperature.

Hydrogels, composed of poly(N-vinyl-2-pyrrolidone) and crosslinked polyacrylamide, were synthesized and the release of vitamin B12 from these hydrogels was studied as a function of the degree of crosslinking and pH of the external swelling media. The three drug-loaded hydrogel samples synthesized with different crosslinking ratios of 0.3, 0.7, and 1.2 (in mol %) follow different drug-release mechanisms, that is, chain relaxation with zero-order, non-Fickian and Fickian, or diffusion-controlled mechanisms. To establish a correlation between their swelling behavior and drug-release mechanism, the former was studied by the weight-gain method and, at the same time, the concentration of the drug released was studied colorimetrically. Various swelling parameters such as the swelling exponent n, gel-characteristic constant k, penetration velocity v, and diffusion coefficient D were evaluated to reflect the quantitative aspect of the swelling behavior of these hydrogels. Finally, the drug-release behavior of the hydrogels was explained by proposing the swelling-dependent mechanism. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1706–1714, 2000

Large steel mills can be potentially harsh loads on an electric power system, producing harmonic currents and unbalanced system loading. Since these large loads are typically supplied from the EHV power system grid, it must be recognized that not only will the system of the host utility be impacted, but neighboring utility systems could be impacted as well. Existing IEEE Standard 519-1992, IEEE Recommended Practices and Requirements for Harmonic Control in Electrical Power Systems, does not fully address the interharmonic problems generated by steel mill loads. This paper identifies the limits of existing unit protection schemes to detect the potentially damaging impacts which large mill loads can have on nearby power generating units. Preoperational studies are needed to assess the impact of the mill on the power system, followed by field tests to verify the study results. Potential mitigation schemes to protect generating units are identified. Issues are discussed from both a utility and mill perspective. Additionally, the paper provides information needed by both the utility protection engineer and the mill's operators during initial planning discussions prior to operation.

The practice of tripping the generator breakers immediately following a boiler/turbine trip exposes a steam turbine generator to a potentially damaging overspeed operating condition. This paper describes the use of the sequential trip mode as a means of minimizing the exposure to possible unit damage following a boiler/turbine trip. Included is a comparison of the application of devices used by several major steam turbine generator manufacturers in accomplishing sequential tripping of the unit. This paper also discusses the differences in the devices used in implementing the tripping scheme and those applied as backup motoring protection. Additionally, the paper provides guidance in the selection of which functions should and should not be used to initiate sequential tripping.

The uniqueness of the electrical environment (asynchronous connection to power system, variable frequency operation, and harmonics) on the output of adjustable speed drives (ASDs) requires special consideration to be given to the motor protection. The Working Group has investigated and addressed these concerns. This paper announces the report on the findings of this activity and the recommendations made to the motor protection engineer. The full report can be found at www.pes-psrc.org under Published Reports.

In majority of individuals blood pressure rises in the early morning hours, which lead to serious cardiovascular complications. Formulation of pulsatile system makes it possible to deliver drug at definite period of time when symptoms of the disease condition are most critical. The purpose of the present work was to develop pulsatile release tablet of losartan potassium for chronotherapy in hypertension. The prepared system consisted of a core tablet coated with versatile and safe hydrophilic cellulosic ethers such as, hydroxypropyl methylcellulose, hydroxypropyl cellulose and sodium carboxy methylcellulose to produce burst release after predetermined lag time. Various formulation factors were studied through series of test and in vitro dissolution study. It was found that core tablets containing superdisintegrant failed to produce burst drug release pattern while effervescent agent was able to do so. Results also reveal that coating composition and coating level affects lag time. Formulation containing effervescent agent in core and coated with 200 mg hydroxypropyl cellulose provide lag time of 4.5 h with 73% drug release in 6 h that followed a sigmoidal release pattern. These values were close to the desired objective of producing lag time of 5â??6 h followed by fast drug release. This approach can thus provide a useful means for timed release of losartan and is helpful for patients with morning surge.