Effect of core hydrophobicity on the electrophoresis of pH-regulated soft particles.

We propose a theoretical study on the electrophoresis of core-shell composite soft particles considering the effect of hydrodynamic slip length of the hydrophobic inner core. The surface of the inner core as well as the soft polymeric shell bear zwitterionic functional groups and the charged conditions depend on the nearby micro-environment. Within a low potential and weak electric field framework, the mathematical equations of the generalized electrokinetic theory for soft surfaces are solved analytically subject to appropriate boundary conditions, and a general electrophoretic mobility expression in an integral form involving the pH-dependent electrostatic potential is derived. With the help of suitable numerical schemes, electrophoretic mobility can easily be obtained. The effect of hydrophobicity of the inner core on the electrophoretic mobility of pH-regulated soft particles is illustrated for a wide range of pertinent parameters.

Electrophoresis of hydrophilic/hydrophobic rigid colloid with effects of relaxation and ion size.

This article deals with a semi-analytical study on the electrophoresis of charged spherical rigid colloid by considering the effects of relaxation and ion size. The particle surface is taken to be either hydrophilic or hydrophobic in nature. In order to consider the ion size effect we have invoked the Carnahan and Starling model (J. Chem. Phys. 1969, 51, 635-636). The mathematical model is based on Stokes equation for fluid flow, modified Boltzmann equation for spatial distribution of ionic species and Poisson equation for electric potential. We adopt a linear perturbation technique under a weak electric field assumption. An iterative numerical technique in employed to solve the coupled set of perturbed equations. We have validated the numerically obtained electrophoretic mobility with the corresponding analytical solution derived under low potential limit. Going beyond the widely employed Debye-Hückel linearization, we have presented the results for a wide range of surface charge density, electrolyte concentration, and slip length to Debye length ratio. We have also identified several interesting features including occurrence of local maxima and minima in the mobility for critical choice of pertinent parameters.

Analysis and design of hybrid ARROW-B plasmonic waveguides.

A hybrid antiresonant reflecting waveguide, type B (ARROW-B) plasmonic waveguide based on the resonant coupling between a guided dielectric mode and surface plasmon polariton wave is proposed. Employing the finite element method, hybrid modes including two bound supermodes are obtained at visible frequencies by varying the environmental refractive index. We investigate the propagation characteristics of hybrid modes, where the significant change of modal power by the symmetric bound mode is observed in plasmonic waveguide coupling suitable for highly sensitive detection of bulk refractive index change. Further, anomalous dispersion is shown by the antisymmetric bound mode which leads to large group velocity dispersion of -3.165×10(4) ps/km nm and, thus, makes this hybrid plasmonic waveguide ideal for observation of soliton generation.

Plasmonic Copper-activated ZnO Microarrays for Efficient Photoelectrocatalytic Applications.

In the present work, green synthesized plasmonic copper nanostructures derived from carbon quantum dots (PCQDs) activated ZnO microarrays (MAs) based catalyst system is developed and studied for photocatalytic activity and photoelectrocatalytic water splitting. CQDs are synthesized from pharmaceutical waste and used as a reducing agent to synthesize PCQDs of an average size of 10±2 nm. PCQDs decorated ZnO (PCQDs/ZnO) MAs exhibited enhanced photocurrent density of ∼7.1 mA/cm2 at 1.23 V (vs. RHE), which is ∼11 fold to ZnO MAs alone (0.65 mA/cm2 ). The catalyst exhibits an ABPE of 1.07% at 0.7 V (vs. RHE), IPEC of 8.8% for 450 nm, and hydrogen production rate of 435 µmol/h. The enhanced PEC characteristics are assigned to the improved photons collection and better charge transfer for their participation in oxidation/reduction reaction. The same is well supported with DFT studies for the PCQDs/ZnO MAs catalyst for the first time.

Nonlinear pulse propagation in chalcogenide As2Se3 glass photonic crystal fiber using RK4IP method.

Pulse propagation through chalcogenide As(2)Se(3) glass photonic crystal fiber (PCF) is numerically investigated using fourth-order Runge-Kutta in the interaction picture (RK4IP) method. The fully vectorial effective index method (FVEIM) is used to calculate the variation of effective refractive index, effective area, dispersion, and nonlinear coefficient (γ) in As(2)Se(3) PCF with wavelength for different values of pitch and air hole size. The RK4IP method is used to demonstrate the soliton propagation, self-phase modulation (SPM), soliton collision and cross phase modulation (XPM) in the designed As(2)Se(3) PCF. The numerically obtained value of soliton collision length (L(col)=51.3L(D)) using the RK4IP method is found to be in good agreement with the theoretical value of soliton collision length (L(col)=51.408L(D)) obtained from inverse scattering transform method, thus providing a verification of the RK4IP accuracy in solving generalized nonlinear schrödinger equation (GLNSE). We also evaluate and apply the value of wavelength for distortionless (L(NL)=L(D)) propagation of the soliton pulse.

Quality differentials and reproductive health service utilisation determinants in India.

PURPOSE: This paper seeks to establish relationships between women's reproductive health service use, assessed longitudinally and by facility type, with service quality perceptions related to public or private health facilities. DESIGN/METHODOLOGY/APPROACH: The study was mainly secondary and quantitative in nature. It included analysing data collected by the International Institute for Population Sciences (IIPS) and The Johns Hopkins University (JHU) as a follow-up study to the 1998-1999 National Family Health Survey (NFHS-2). The follow-up survey was carried out in Tamil Nadu, Maharashtra, Bihar and Jharkhand. In 2002-2003, these four states were selected to capture socio-economic and demographic variations. Analysis includes composite indices and logistic regression analysis. A scale was constructed to measure utilisation levels. Dimensions include: service proximity, doctor availability, waiting time, medicines, facility cleanliness, dignified treatment, privacy, service affordability and treatment effectiveness. FINDINGS: Findings indicate that doctor availability, waiting time, cleanliness, privacy and affordability at private health facilities enhance the probability that a health facility will be used for any reproductive health purpose. At the combined states level, medicine availability and treatment effectiveness at public health facilities enhances service use. RESEARCH LIMITATIONS/IMPLICATIONS: The major limitation is that the study includes only selected Indian states. PRACTICAL IMPLICATIONS: The findings may enhance Indian service-quality policy. ORIGINALITY/VALUE: The paper's main contribution is that seemingly for the first time in India, healthcare service use has been measured longitudinally and then explained through service quality variables by comparing public and private health facilities.

TiO2 nanofibres decorated with green-synthesized PAu/Ag@CQDs for the efficient photocatalytic degradation of organic dyes and pharmaceutical drugs.

Organic pollutants such as dyes and pharmaceutical drugs have become an environmental menace, particularly in water bodies owing to their unregulated discharge. It is thus required to develop an economically viable and environment-friendly approach for their degradation in water bodies. In this study, for the first time, we report green route-synthesized plasmonic nanostructures (PM-CQDs (where M: Au and Ag)) decorated onto TiO2 nanofibers for the treatment of toxic dye- and pharmaceutical drug-based wastewater. PM-CQDs are efficaciously synthesized using carbon quantum dots (CQDs) as the sole reducing and capping agent, wherein CQDs are derived via a green synthesis approach from Citrus limetta waste. The characteristic electron-donating property of CQDs played a key role in the reduction of Au3+ to Au0 and Ag+ to Ag0 under visible light irradiation to obtain PAu-CQDs and PAg-CQDs, respectively. Thus, the obtained CQDs, PAu-CQDs, and PAg-CQDs are loaded onto TiO2 nanofibers to obtain a PM-CQD/TiO2 nanocomposite (NC), and are further probed via transmission electron microscopy, scanning electron microscopy and UV-visible spectrophotometry. The degradation of organic pollutants and pharmaceutical drugs using methylene blue and erythromycin as model pollutants is mapped with UV-vis and NMR spectroscopy. The results demonstrate the complete MB dye degradation in 20 minutes with 1 mg mL-1 of PAu-CQD/TiO2 NC, which otherwise is 30 minutes for PAg@CQD/TiO2 dose under visible light irradiation. Similarly, the pharmaceutical drug was found to degrade in 150 minutes with PAu-CQD/TiO2 photocatalysts. These findings reveal the enhanced photocatalytic performance of the green-synthesized Au decorated with TiO2 nanofibers and are attributed to the boosted SPR effect and aqueous-phase stability of Au nanostructures. This study opens a new domain of utilizing waste-derived and green-synthesized plasmonic nanostructures for the degradation of toxic/hazardous dyes and pharmaceutical pollutants in water.

Electrophoresis of dielectric and immiscible-liquid-layer-encapsulated colloids in aqueous media.

In this paper we consider the electrophoresis of a functionalized nanoparticle in electrolyte solution. The undertaken particle is comprised of a rigid inner core encapsulated with a layer of dielectric liquid (e.g., oil or lipid layer), which is immiscible to the bulk aqueous medium. The peripheral liquid layer of the undertaken nanoparticle contains mobile charges due to presence of solubilized surfactants. The mobile electrolyte ions can penetrate across the peripheral layer depending on the difference in the Born energy of the both phases. Such types of nanoparticles have received substantial attention due to their widespread applications in biomedical research. The electric double layer (EDL) is governed by the linearized Poisson-Boltzmann equation under a low potential limit and the electroosmotic flow field is governed by modified Stokes equation. We adopt the flat-plate formalism to obtain the closed analytical expression for the electrophoretic mobility of the undertaken particle under a thin EDL approximation. The dependence of electrophoretic mobility on the pertinent parameters is also illustrated.

Strategies for realizing photonic crystal fiber bandpass filters.

Numerical design strategies are presented to achieve efficient broad or narrow band-pass filters based on index-guiding, solid-core, and single-mode photonic crystal fibers (PCFs). The filtering characteristics have been verified through BPM solver. By scaling the pitch constant, the bandpass window can be shifted accordingly. The fiber design constitutes a fluorine-doped central core, enlarged air-holes surrounding the down-doped core, and small air-holes in the cladding. The proposed bandpass filter is based on controlling the leakage losses, so one can tune filter characteristics simply by changing its length. From numerical simulations we show that for large values of air-hole diameter in the first ring, the bandpass window is narrow, while for low doping concentration and small sized air-holes in the first ring, bandpass window is very broad. We also simulate how the hole-size and number of rings in the PCF cladding affects the device characteristics. We find that a 5-cm long PCF with down-doped core and eleven rings of air-holes can result in approximately 440 nm 3-dB bandwidth with more than 90% of transmission. The longer device has reduced transmission and smaller 3-dB bandwidth. Tolerance analysis has also been performed to check the impact of fiber tolerances on the performance of the PCF bandpass filter. It has been observed that the decrement in cladding hole-diameter by 1% reduces the transmission to 21% from its peak value of 93%, however +/-1% tolerance in the inner hole-diameter degrades the transmission to 75% from its peak.

Consistency and predictive ability of fertility preference indicators: longitudinal evidence from rural India.

CONTEXT: Ideal family size and desire for an additional child are the two most commonly used fertility preference indicators. However, little is known about the consistency over time of responses to each measure, the consistency between the two indicators or the predictive value of these indicators in India. METHOD: Longitudinal data from the 1998-1999 National Family Health Survey and a follow-up survey conducted four years later were analyzed to determine the consistency of responses to the two fertility preference indicators (both over time and between indicators) and to determine whether baseline responses were associated with subsequent fertility, unwanted births and contraceptive use. RESULTS: Responses on the measure of ideal family size were consistent at the two time points for 53% of nonsterilized women. Eighty-two percent of women who explicitly said in 1998 that they did not desire more children responded identically in 2002, although about half of these women had given birth in the intervening period. The indicators were associated with each other: Among women with at least one son, 79% of those who had attained or surpassed their ideal family size said they wanted to stop childbearing, compared with 18% of those who had not. Both indicators predicted future fertility, unwanted births and contraceptive use, particularly among women who had a son. CONCLUSION: Both indicators are useful in understanding future fertility behavior. As the prevalence of son preference declines in India, the predictive ability of the indicators is likely to improve.

Consent and coercion: examining unwanted sex among married young women in India.

CONTEXT: Although there is a growing body of research examining the issue of nonconsensual sex among adolescents, few studies have looked at coerced sex within marriage in settings where early marriage is common, or at sex that may not be perceived as forced, but that is unwanted. METHODS: A cross-sectional study, using both survey research and in-depth interviews, was conducted among 1,664 married young women in Gujarat and West Bengal, India. Descriptive data and multinomial logistic regression were used to identify the prevalence and risk factors for occasional and frequent unwanted sex. Qualitative data were analyzed to examine the context in which unwanted sex takes place. RESULTS: Twelve percent of married young women experienced unwanted sex frequently; 32% experienced it occasionally. The risk of experiencing unwanted sex was lower among women who knew their husband fairly well at the time of marriage, regularly received support from their husband in conflicts with other family members or lived in economically better-off households. Frequent unwanted sex was associated with not yet having had a child or having become pregnant, with lower education and with agreeing with norms that justify wife beating. CONCLUSION: For married young women, sex is not always consensual or wanted. Further research is required to determine the effects of unwanted sex on sexual and reproductive health outcomes and to help programs develop the best strategies for dealing with coerced sex within marriage.

New directions in the science and technology of advanced sheet explosive formulations and the key energetic materials used in the processing of sheet explosives: Emerging trends.

This review presents the work carried out by the international community in the area of sheet explosive formulations and its applications in various systems. The sheet explosive is also named as PBXs and is a composite material in which solid explosive particles like RDX, HMX or PETN are dispersed in a polymeric matrix, forms a flexible material that can be rolled/cut into sheet form which can be applied to any complex contour. The designed sheet explosive must possess characteristic properties such as flexible, cuttable, water proof, easily initiable, and safe handling. The sheet explosives are being used for protecting tanks (ERA), light combat vehicle and futuristic infantry carrier vehicle from different attacking war heads etc. Besides, sheet explosives find wide applications in demolition of bridges, ships, cutting and metal cladding. This review also covers the aspects such as risks and hazard analysis during the processing of sheet explosive formulations, effect of ageing on sheet explosives, detection and analysis of sheet explosive ingredients and the R&D efforts of Indian researchers in the development of sheet explosive formulations. To the best of our knowledge, there has been no review article published in the literature in the area of sheet explosives.

Regulation of human osteoblast integrin expression by orthopedic implant materials.

Integrins are transmembrane proteins that mediate attachment to extracellular matrix (ECM) proteins. Integrins act as ECM receptors and are believed to play a role in signal transduction and gene regulation, potentially influencing several cellular functions, including differentiation, growth, and migration. Several integrins have previously been found in bone cells in vivo and in vitro. Because the biologic fixation of orthopedic implants depends on optimal cell interactions at the interface, we examined whether integrins are involved in the attachment of osteoblasts to implant materials. In this study, we have used immunohistochemistry to examine the expression of integrins in primary human osteoblasts cultured on tissue culture polystyrene (PS), and rough and polished disks of the orthopedic alloys titanium-aluminum-vanadium (Ti) and cobalt-chrome-molybdenum (CC). The integrin subunits, alpha 2, alpha 3, alpha 4, alpha 5, alpha v, alpha 6, beta 1 and beta 3, were expressed by primary human osteoblasts cultured on PS coated with various ECM molecules. However, alpha 5 and alpha 6 were notably absent in cells attached to the alloys. Also, alpha 3 was not present on rough Ti, polished CC, or rough CC, and beta 3 was not expressed by cells on rough CC. Thus, the nature of the metal alloy appeared to influence the expression of particular integrins. As a result, the ability of cells to adhere to and receive messages from the extracellular matrix may also be influenced by the substratum. These differences may explain previously observed differences in degree of cell attachment to these metals.

High-resolution morphometric analysis of human osteoblastic cell adhesion on clinically relevant orthopedic alloys.

Understanding the cellular basis of osteoblastic cell-biomaterial interaction is crucial to the analysis of the mechanism of osseointegration, a requirement of long-term orthopedic implant stability. Clinically, the amount of bone ingrowth is variable, and cellular parameters that influence ingrowth have yet to be clearly determined. In this study, two clinically relevant orthopedic alloys, titanium Ti6A14V (Ti) and cobalt-chrome-molybdenum (CC), were used for a comparative analysis of primary human osteoblastic cell adhesion and spreading, where cell adhesion represents the initial interaction between cellular elements and the biomaterial surface. The kinetic profile of adhesion revealed enhanced cell attachment upon rough Ti surfaces relative to rough CC. Using confocal laser scanning microscopy (CLSM), we observed that, during the first 12 h of contact with the substratum, osteoblastic cells were relatively less spread on rough Ti, whereas cells appeared elongated with multiple cellular extensions on rough CC. Focal adhesion contacts, as indicated by vinculin immunostaining, were distributed throughout the cells adhering to Ti, but were relatively sparse and localized to cellular processes on CC. Furthermore, three-dimensional CLSM reconstruction analysis indicated the presence of vinculin at all membrane-to-surface contact points on both Ti and CC. On Ti, these contact points closely followed the surface contour, whereas, on CC, they were restricted to relative topographic peaks only. Actin cytoskeletal reorganization was prominent in cells cultured on Ti, with stress fibers arranged throughout the cell body, whereas, on CC, actin filaments were sparse and localized primarily to cellular extensions. Because cell attachment mechanisms are likely to influence signal transduction and regulation of gene expression, these early differential responses of osteoblastic cells on Ti and CC may have functional implications on subsequent extracellular matrix mineralization and bone ingrowth at the cell-biomaterial interface.

Prevalence of micronutrient deficiency based on results obtained from the national pilot program on control of micronutrient malnutrition.

Micronutrient deficiency is a serious public health concern in most developing countries. In India, iron deficiency, vitamin A deficiency, and iodine deficiency disorder are of greatest public health significance. In addition, subclinical zinc deficiency, flourosis, and fluoride-deficient dental caries are important areas of concern. The National Pilot Program on Control of Micronutrient Malnutrition was launched in 1995 to address these problems and the Department of Biochemistry and Nutrition of the All India Institute of Hygiene and Public Health (Calcutta) was entrusted to coordinate its activities. The program presently covers one northeastern and four eastern states, namely Assam, Bihar (Jharkhand), Orissa, West Bengal, and Tripura. Baseline analyses were conducted on demographic situation, food and nutrient intake pattern, nutritional deficiency diseases (e.g., iron deficiency anemia), iodine deficiency disorder, and vitamin A deficiency. It was observed that except for cereals, the diet was deficient in all other food groups. Nutrient intake (i.e., energy, protein, vitamins, and minerals) was also deficient in almost the entire state. Anthropometric indices (e.g., weight-for-age and height-for-age data) indicated that large percentages of <5-year-old and 6-14-year-old children were in grade II or III malnutrition. Mean dietary zinc intakes in all the surveyed districts were much lower than the RDA. Large percentages of salt samples had iodine levels less than 15 ppm. The point prevalence of anemia in various age groups was found to be high. Bitot's spot was mainly noted in the age group of 6-71 months. Nightblindness was noted in young children as well as the children 24-71 months old. High prevalence of nightblindness in pregnant women is a point of concern. Actions needed to control micronutrient deficiencies include: intervention strategies, extensive nutrition and health education through innovative IEC materials to support problem-specific programs, strengthening of various state government programs and the role of NGOs.

A comparison of pedicled and free TRAM flaps for breast reconstruction in a single institution.

Several reports concluded that free tissue transfer of the transverse rectus abdominis muscle (TRAM) flap for breast reconstruction is superior to pedicled transfer of the flap. In an effort to compare the various parameters of both techniques, the authors took advantage of a unique experience at one hospital where one surgeon (D.L.L.) used only the pedicled method and the other (N.J.Y.) used only free tissue transfer. Additionally, the authors compared the findings of the study with the experiences of other surgeons by surveying active members of the American Association of Plastic Surgeons. The records of 119 patients who underwent TRAM flap reconstruction between January of 1988 and July of 1997 were reviewed. Of these, 33 patients received free TRAM flaps, and 86 received pedicled TRAM flaps. To provide an adequate number of patients for statistical analysis, only those with unilateral, single-muscle reconstructions were considered (immediate or delayed). This provided 61 patients in the pedicled flap group and 26 in the free tissue group. Parameters examined included length of operation and of hospitalization, amount of pain medication used, amount of blood lost and received, and complications. A small subset of the patients had hospital records available to compare hospital charges; the comparison of 17 pedicled and 12 free TRAM flaps showed a mean difference of $15,637 (p < 0.001) in favor of the pedicled flap. On the basis of the findings from this study, it seems that the pedicled TRAM flap has significant economic and clinical advantages over the free TRAM flap. There is less need for blood, a shorter operating time and hospital stay, and a need for less pain medication. However, both methods of transfer have indications and contraindications in certain clinical settings. It will always remain the responsibility of the surgeon to evaluate all issues and select a method that is economically responsible and within the abilities of the surgeon, while producing a satisfactory outcome that best serves the patient. The information provided in this report should aid in accomplishing this goal.

Pathogenesis of bone loss after total hip arthroplasty.

Bone loss with or without evidence of aseptic loosening is a long term complication after total hip arthroplasty (THA). It occurs with all materials and in all prosthetic systems in use or that have been used to date. Bone loss after THA can be a serious problem in revision surgery because bone deficiencies may limit reconstructive options, increase the difficulty of surgery, and necessitate autogenous or allogenic bone grafting. There are three factors adversely affecting maintenance of bone mass after THA: (1) bone loss secondary to particulate debris; (2) adaptive bone remodeling and stress shielding secondary to size, material properties, and surface characteristics of contemporary prostheses; and (3) bone loss as a consequence of natural aging. This chapter reviews the mechanisms of the primary causes of bone loss after THA.

Artificial neural network detects changes in electro-encephalogram power spectrum of different sleep-wake states in an animal model of heat stress.

An effective application is presented of a back-propagation artificial neural network (ANN) in differentiating electro-encephalogram (EEG) power spectra of stressed and normal rats in three sleep-wakefulness stages. The rats were divided into three groups, one subjected to acute heat stress, one subjected to chronic heat stress and one a handling control group. The polygraphic sleep recordings were performed by simultaneous recording of cortical EEG, electro-oculogram (EOG) and electromyogram (EMG) on paper and in digital form on a computer hard disk. The preprocessed EEG signals (after removal of DC components and reduction of baseline movement) were fragmented into 2 s artifact-free epochs for the calculation of power spectra. The slow-wave sleep (SWS), rapid eye movement (REM) sleep and awake (AWA) states were analysed separately. The power spectrum data for all three sleep-wake states in the three groups of rats were tested by a back-propagation ANN. The network contained 60 nodes in the input layer, weighted from power spectrum data from 0 to 30 Hz, 18 nodes in the hidden layer and an output node. The ANN was found effective in differentiating the EEG power spectra from stressed to normal spectral patterns following acute (92% in SWS, 85.5% in REM sleep, 91% in AWA state) as well as chronic heat exposure (95.5% in SWS, 93.8% in REM sleep, 98.5% in AWA state).

Electro-encephalogram disturbances in different sleep-wake states following exposure to high environmental heat.

In this study, cerebral electrical activity or electro-encephalogram (EEG) was studied following exposure to high environmental heat, in three different age groups of freely moving rats. Each age group was subdivided into three groups: the acute heat stress group, subjected to a single exposure of 4 h at 38 degrees C in the biological oxygen demand incubator; the chronic heat stress group, exposed for 21 days, for 1 h each day, at 38 degrees C in the incubator; and the handling control group. The polygraphic sleep-wake recordings involved simultaneous recordings of cortical EEG, electro-oculogram (EOG), and electromyogram (EMG), on paper and in digital form on computer hard disk, just after the heat exposure for the acute stressed rats and on the 22nd day for the chronic stressed rats. The power spectrum was calculated for 2s epochs of the EEG signals. Quantitative analyses of EEG (qEEG) showed that, in all three age groups, changes in higher-frequency components (beta2) were significant in all sleep-wake states following both acute and chronic heat stress conditions. The power of beta2 activity in all three age groups after acute heat exposure was significantly decreased during slow wave sleep (SWS) (p < 0.05) and rapid eye movement sleep (p < 0.05), whereas the reverse was observed in the awake state (p < 0.05). Following chronic heat exposure, beta2 activity was found to increase in all three sleep-wake stages in all groups of rats (p < 0.01 for SWS in the weaning group and p < 0.05 for other data). Thus the study demonstrated that the cortical EEG is sensitive to environmental heat, and alterations in EEG frequencies in different states of mental consciousness due to high heat can be differentiated efficiently by EEG power spectrum analysis.