Fabrication and characterization of binary composite MgO/CuO nanostructures for the efficient photocatalytic ability to eliminate organic contaminants: A detailed spectroscopic analysis

Design and eco-friendly fabrication of affordable and sustainable materials for the treatment of wastewater consisting of dyes, antibiotics, and other harmful substances has always been demanding. Untreated wastewater being released from industries imposes serious threats to our ecosystem, seeking convenient approaches to diminish this alarming issue. Here in this work, we synthesized MgO/CuO nanocomposites from a plant extract of Ammi visnaga L. and then employed these nanocomposites for the treatment of organic dye (methylene blue). We characterized the synthesized nanocomposites by dynamic light scattering (DLS), zeta potential, scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and X-ray photoelectron microscopy (XPS). DLS presented information about the explicit size of nanocomposites, while the surface charge was examined by zeta potential. XRD provided detailed information about the crystalline behavior and the information regarding surface morphology and size was extracted by SEM, TEM, and AFM. Moreover, the fabricated nanocomposites were used as a photocatalyst in the treatment of methylene blue. The overall catalytic reaction took an hour to complete, and the value of percentage degradation was 98 %. Substantially, a detailed account of the kinetics, rate of reaction, and mechanism is also fostered in the context. The presented study can assist scientists and researchers around the world to reproduce the results and use them to apply them on a broader scale.

Solving the fouling mechanisms in composite membranes for water purification: An advance approach

With the increasing population worldwide more wastewater is created by human activities and discharged into the waterbodies. This is causing the contamination of aquatic bodies, thus disturbing the marine ecosystems. The rising population is also posing a challenge to meet the demands of fresh drinking water in the water-scarce regions of the world, where drinking water is made available to people by desalination process. The fouling of composite membranes remains a major challenge in water desalination. In this innovative study, we present a novel probabilistic approach to analyse and anticipate the predominant fouling mechanisms in the filtration process. Our establishment of a robust theoretical framework hinges upon the utilization of both the geometric law and the Hermia model, elucidating the concept of resistance in series (RIS). By manipulating the transmembrane pressure, we demonstrate effective management of permeate flux rate and overall product quality. Our investigations reveal a decrease in permeate flux in three distinct phases over time, with the final stage marked by a significant reduction due to the accumulation of a denser cake layer. Additionally, an increase in transmembrane pressure leads to a correlative rise in permeate flux, while also exerting negative effects such as membrane ruptures. Our study highlights the minimal immediate impact of the intermediate blocking mechanism (n = 1) on permeate flux, necessitating continuous monitoring for potential long-term effects. Additionally, we note a reduced membrane selectivity across all three fouling types (n = 0, n = 1.5, n = 2). Ultimately, our findings indicate that the membrane undergoes complete fouling with a probability of P = 0.9 in the presence of all three fouling mechanisms. This situation renders the membrane unable to produce water at its previous flow rate, resulting in a significant reduction in the desalination plant's productivity. I have demonstrated that higher pressure values notably correlate with increased permeate flux across all four membrane types. This correlation highlights the significant role of TMP in enhancing the production rate of purified water or desired substances through membrane filtration systems. Our innovative approach opens new perspectives for water desalination management and optimization, providing crucial insights into fouling mechanisms and proposing potential strategies to address associated challenges.

Insight into mechanism of excellent visible-light photocatalytic activity of CuO/MgO/ZnO nanocomposite for advanced solution of environmental remediation

Environmental remediation has sought several innovative ways for the treatment of wastewater and captivated researchers around the globe towards it. Through this study, we aim to proceed with the efforts to foster sustainable and feasible ways for the treatment of wastewater. In this work, we report the sol-gel synthesis of CuO/MgO/ZnO nanocomposite and carry out their systematic characterization with the help of state-of-the-art analytical techniques, such as FTIR, SEM, TEM, PL, XRD, Raman, and AFM. The SEM along with TEM and AFM provided useful insights into the surface morphology of the synthesized nanocomposite on both 2D and 3D surfaces and concluded the well-dispersed behavior of the nanocomposite. The characteristic functional groups responsible for carrying out the reaction of Cu-O, Mg-O, and Zn-O were identified by FTIR spectroscopy. On the other hand, crystal size, dislocation density, and microstrain of the nanocomposite were calculated by XRD. For optical studies, photoluminescence spectroscopy was performed. Once the characterization of the nanocomposite was done, they were eventually treated against the toxic organic dye, methylene blue. The calculated rate constant values of k for CuO was 2.48 × 10-3 min-1, for CuO/MgO (2.04 × 10-3 min-1), for CuO/ZnO (1.82 × 10-3 min-1) and CuO/MgO/ZnO was found to be 2.00 × 10-3 min-1. It has become increasingly evident that nanotechnology can be used in various facets of modern life, and its implementation in wastewater treatment has recently received much attention.

Synthesis of carbon nanotubes-chitosan nanocomposite and immunosensor fabrication for myoglobin detection: An acute myocardial infarction biomarker

The use of single-walled carbon nanotubes (SWCNTs) in biomedical applications is limited due to their inability to disperse in aqueous solutions. In this study, dispersed -COOH functionalized CNTs with N-succinylated chitosan (CS), greatly increasing the water solubility of CNTs and forming a uniformly dispersed nanocomposite solution of CNTs@CS. Coupling reagent EDC/NHS was used as a linker with the -COOH groups present on the N-succinylated chitosan which significantly improved the affinity of the CNTs for biomolecules. Myoglobin (Mb) is a promising biomarker for the precise assessment of cardiovascular risk, type 2 diabetes, metabolic syndrome, hypertension and several types of cancer. A high level of Mb can be used to diagnose the mentioned pathogenic diseases. The CNTs@CS-FET demonstrates superior sensing performance for Mb antigen fortified in buffer, with a wide linear range of 1 to 4000 ng/mL. The detection limit of the developed Mb immunosensor was estimated to be 4.2 ng/mL. The novel CNTs@CS-FET immunosensor demonstrates remarkable capability in detecting Mb without being affected by interferences from nonspecific antigens. Mb spiked serum showed a recovery rate of 100.262 to 118.55 % indicating great promise for Mb detection in clinical samples. The experimental results confirmed that the CNTs@CS-FET immunosensor had excellent selectivity, reproducibility and storage stability.

Label-free and ultrasensitive electrochemical transferrin detection biosensor based on a glassy carbon electrode and gold nanoparticles

In this study, we developed a label-free and ultrasensitive electrochemical biosensor for the detection of transferrin (Tf), an important serum biomarker of atransferrinemia. The biosensor was fabricated by using glassy carbon electrode (GCE) and modified with gold nanoparticles (AuNPs) via electroless deposition. The electrochemical characteristics of the GCE-AuNPs biosensors were characterized using cyclic voltammetry and electrochemical impedance spectroscopy analysis. Differential pulse voltammetry was used for quantitative evaluation of the Tf-antigen by recording the increase in the anodic peak current of GCE-AuNPs biosensor. The GCE-AuNPs biosensor demonstrates superior sensing performance for Tf-antigen fortified in buffer, with a wide linear range of 0.1 to 5000 μg/mL and a limit of detection of 0.18 μg/mL. The studied GCE-AuNPs biosensor showed excellent sensitivity, selectivity, long-term storage stability and simple sensing steps without pretreatment of clinical samples. This GCE-AuNPs biosensor indicates great potential for developing a Tf detection platform, which would be helpful in the early diagnosis of atransferrinemia. The developed GCE-AuNPs biosensor holds great potential in biomedical research related to point of care for the early diagnosis and monitoring of diseases associated with aberrant serum transferrin levels. These findings suggest that the GCE-AuNPs biosensor has great potential for detecting other serum biomarkers.

Sulfur-doped graphitic carbon nitride: Tailored nanostructures for photocatalytic, sensing, and energy storage applications

Rapid globalization and industrialization have led to widespread pollution and energy crises, necessitating the development of innovative solutions. Metal-free g-C3N4-based polymeric materials have unique properties but face limitations such as low surface area and inefficient light absorption. Doping, especially sulfur doping, is a prevalent technique to enhance their optical and electronic properties. This comprehensive review focuses on the synthesis techniques employed for sulfur doping of g-C3N4 (S-CN), highlighting the complexities associated with S-doping and the advantages of co-doping. Additionally, the review encompasses the diverse applications of S-CN in catalysis, photocatalysis, sonocatalysis, pollutant remediation, and electrochemical sensing. By incorporating sulfur into the g-C3N4 structure, various desirable properties can be achieved, including improved light absorption efficiency and enhanced charge carrier separation and migration. These advancements have broadened the application potential of S-CN in a range of important fields. S-CN has shown promise as a catalyst, facilitating various chemical reactions, as well as a photocatalyst, harnessing solar energy for environmental remediation and energy conversion processes. Moreover, S-CN exhibits potential in sonocatalysis for ultrasound-mediated reactions, pollutant remediation, and electrochemical sensing applications.

Synthesis of activated biochar from sustainable bamboo resources: An environment-friendly and low-cost solution for palladium (II) removal from wastewater

This article highlights the developing capabilities of low-cost activated biochar from bamboo waste used for Palladium (II) (Pd(II)) separation from man-made electroless plating solutions (ELP). From a novelty perspective, this article addresses the effect of coupled sonication and surfactant for the adsorptive elimination of Pd(II) on Bamboo stem activated carbon (BSAC) from ELP. The optimal activation procedure referred to an acid-to-bamboo ratio of 4:1 at sintering of 600-900 °C, which provided an activated carbon (AC) adsorbent with surface area analysis (BET) of 1014.36 m2/g, a value comparable to the commercially procured AC. Pd(II) adsorption characteristics in the solution of Pd with 50-500 mg/L concentration range were evaluated utilizing both agitation and sonication. Adsorption time, pH, dose, and adsorbate concentration were among the pertinent optimal batch adsorption parameters that were found. When utilizing ELP solutions without surfactant, the proposed adsorbent for agitation-assisted adsorption had a simultaneous improvement in metal intake of 6.68-43.2 mg/g and removal efficiency of 72.96-54.5% (cTAB). For cTAB-containing solutions, sonication and agitation-assisted adsorption were outperformed in terms of removal efficiency of 80.32-60.16% and metal uptake of 6.69-50.13 mg/g. Equilibrium, kinetic, and thermodynamic models with good fitting to the reported Pd(II) adsorption properties have been developed.

Serum CRP biomarker detection by using carbon nanotube field-effect transistor (CNT-FET) immunosensor

C-reactive protein (CRP) is produced by the liver in response to systemic inflammation caused by bacterial infection, trauma and internal organ failures. CRP serves as a potential biomarker in the precise diagnosis of cardiovascular risk, type-2 diabetes, metabolic syndrome, hypertension and various types of cancers. The pathogenic conditions indicated above are diagnosed by an elevated CRP level in the serum. In this study, we successfully fabricated a highly sensitive and selective carbon nanotube field-effect transistor (CNT-FET) immunosensor for the detection of CRP. The CNTs were deposited on the Si/SiO2 surface, between source-drain electrodes, afterwards modified with well-known linker PBASE and then anti-CRP was immobilized. This anti-CRP functionalized CNT-FET immunosensor exhibits a wide dynamic detection range (0.01-1000 μg/mL) CRP detection, rapid response time (2-3 min) and low variation (<3 %) which can be delivered as a low-cost and rapid clinical detection technology for the early diagnosis of coronary heart disease (CHD). For the clinical applications, our sensor was tested using CRP fortified serum samples and sensing performance was validated using enzyme-linked immune-sorbent assay (ELISA). This CNT-FET immunosensor will be helpful in taking over the complex laboratory-based expensive traditional CRP diagnostic procedures practiced in the hospitals.

Plant Extract-Based Fabrication of Silver Nanoparticles and Their Effective Role in Antibacterial, Anticancer, and Water Treatment Applications

Ammi visnaga is a biennial or annual herbaceous plant belonging to the family Apiaceae. For the first time, silver nanoparticles were synthesized using an extract of this plant. Biofilms are a rich source of many pathogenic organisms and, thus, can be the genesis of various disease outbreaks. In addition, the treatment of cancer is still a critical drawback for mankind. The primary purpose of this research work was to comparatively analyze antibiofilms against Staphylococcus aureus, photocatalytic activity against Eosin Y, and in vitro anticancer activity against the HeLa cell line of silver nanoparticles and Ammi visnaga plant extract. The systematic characterization of synthesized nanoparticles was carried out using UV-Visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), dynamic light scattering (DLS), zeta potential, and X-ray diffraction microscopy (XRD). The initial characterization was performed with UV-Vis spectroscopy, where a peak appeared at 435 nm, which indicated the SPR band of the silver nanoparticles. AFM and SEM were performed to determine the morphology and shape of the nanoparticles, while EDX confirmed the presence of Ag in the spectra. The crystalline character of the silver nanoparticles was concluded with XRD. The synthesized nanoparticles were then subjected to biological activities. The antibacterial activity was evaluated by determining the inhibition of the initial biofilm formation with Staphylococcus aureus using a crystal violet assay. The response of the AgNPs against cellular growth and biofilm formation was found to be dose dependent. Green-synthesized nanoparticles showed 99% inhibition against biofilm and bacteria, performed excellent anticancer assay with an IC₅₀ concentration of 17.1 ± 0.6 µg/mL and 100% inhibition, and photodegradation of the toxic organic dye Eosin Y up to 50%. Moreover, the effect of the pH and dosage of the photocatalyst was also measured to optimize the reaction conditions and maximum photocatalytic potential. Therefore, synthesized silver nanoparticles can be used in the treatment of wastewater contaminated with toxic dyes, pathogenic biofilms, and the treatment of cancer cell lines.

Electrochemical Sensing of H2O2 by Employing a Flexible Fe3O4/Graphene/Carbon Cloth as Working Electrode

We report the synthesis of Fe₃O₄/graphene (Fe₃O₄/Gr) nanocomposite for highly selective and highly sensitive peroxide sensor application. The nanocomposites were produced by a modified co-precipitation method. Further, structural, chemical, and morphological characterization of the Fe₃O₄/Gr was investigated by standard characterization techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and high-resolution TEM (HRTEM), Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The average crystal size of Fe₃O₄ nanoparticles was calculated as 14.5 nm. Moreover, nanocomposite (Fe₃O₄/Gr) was employed to fabricate the flexible electrode using polymeric carbon fiber cloth or carbon cloth (pCFC or CC) as support. The electrochemical performance of as-fabricated Fe₃O₄/Gr/CC was evaluated toward H₂O₂ with excellent electrocatalytic activity. It was found that Fe₃O₄/Gr/CC-based electrodes show a good linear range, high sensitivity, and a low detection limit for H₂O₂ detection. The linear range for the optimized sensor was found to be in the range of 10-110 μM and limit of detection was calculated as 4.79 μM with a sensitivity of 0.037 µA μM^-1 cm^-2. The cost-effective materials used in this work as compared to noble metals provide satisfactory results. As well as showing high stability, the proposed biosensor is also highly reproducible.

A Nanotechnology-Based Approach to Biosensor Application in Current Diabetes Management Practices

Diabetes mellitus is linked to both short-term and long-term health problems. Therefore, its detection at a very basic stage is of utmost importance. Research institutes and medical organizations are increasingly using cost-effective biosensors to monitor human biological processes and provide precise health diagnoses. Biosensors aid in accurate diabetes diagnosis and monitoring for efficient treatment and management. Recent attention to nanotechnology in the fast-evolving area of biosensing has facilitated the advancement of new sensors and sensing processes and improved the performance and sensitivity of current biosensors. Nanotechnology biosensors detect disease and track therapy response. Clinically efficient biosensors are user-friendly, efficient, cheap, and scalable in nanomaterial-based production processes and thus can transform diabetes outcomes. This article is more focused on biosensors and their substantial medical applications. The highlights of the article consist of the different types of biosensing units, the role of biosensors in diabetes, the evolution of glucose sensors, and printed biosensors and biosensing systems. Later on, we were engrossed in the glucose sensors based on biofluids, employing minimally invasive, invasive, and noninvasive technologies to find out the impact of nanotechnology on the biosensors to produce a novel device as a nano-biosensor. In this approach, this article documents major advances in nanotechnology-based biosensors for medical applications, as well as the hurdles they must overcome in clinical practice.

State-of-the-art developments in carbon quantum dots (CQDs): Photo-catalysis, bio-imaging, and bio-sensing applications

Carbon quantum dots (CQDs), the intensifying nanostructured form of carbon material, have exhibited incredible impetus in several research fields such as bio-imaging, bio-sensing, drug delivery systems, optoelectronics, photovoltaics, and photocatalysis, thanks to their exceptional properties. The CQDs show extensive photonic and electronic properties, as well as their light-collecting, tunable photoluminescence, remarkable up-converted photoluminescence, and photo-induced transfer of electrons were widely studied. These properties have great advantages in a variety of visible-light-induced catalytic applications for the purpose of fully utilizing the energy from the solar spectrum. The major purpose of this review is to validate current improvements in the fabrication of CQDs, characteristics, and visible-light-induced catalytic applications, with a focus on CQDs multiple functions in photo-redox processes. We also examine the problems and future directions of CQD-based nanostructured materials in this growing research field, with an eye toward establishing a decisive role for CQDs in photocatalysis, bio-imaging, and bio-sensing applications that are enormously effective and stable over time. In the end, a look forward to future developments is presented, with a view to overcoming challenges and encouraging further research into this promising field.

Graphitic‑carbon nitride based mixed-phase bismuth nanostructures: Tuned optical and structural properties with boosted photocatalytic performance for wastewater decontamination under visible-light irradiation

To enhance the activities of advanced semiconductor photocatalysts, the charge carriers must be separated effectively. One strategy for achieving this is the use of heterogeneous structures, which can be prepared by hydrothermal synthesis and post-synthetic thermal and ultrasonic treatment. Herein, we report a mixed-phase composite of basic bismuth nitrate/pentabismuth heptaoxide nitrate (PC) prepared by hydrothermal synthesis under basic conditions and post-synthetic thermal treatment. In addition, sulfur-doped-graphitic carbon nitride (S-g-C₃N₄) was prepared and combined with PC in different ratios, denoted as PC-1, PC-2, and PC-3, using sonication-assisted treatment. The characterization of these catalysts confirmed the formation of mixed basic bismuth nitrate/pentabismuth heptaoxide nitrate phases and the composite nanostructure. The developed nanostructure showed interesting morphological features, for example, layered sheets of S-g-C₃N₄. The prepared PCs were tested for their visible light responsiveness for the photocatalytic degradation of a representative organic dye (Rhodamine B). We found that the modified photocatalysts showed superior activity to that of pristine PC. The optimal photocatalyst (PC-3) was also used to degrade methylene blue and Congo red, achieving 99% degradation. Thus, we present not only an efficient photocatalyst but also insights into the post-synthetic modification of basic bismuth nitrate/pentabismuth heptaoxide nitrate with stable carbon-based nanostructures.

State-of-the-art developments in carbon-based metal nanocomposites as a catalyst: photocatalysis

The rapid progress of state-of-the-art carbon-based metals as a catalyst is playing a central role in the research area of chemical and materials engineering for effective visible-light-induced catalytic applications. Numerous admirable catalysts have been fabricated, but significant challenges persist to lower the cost and increase the action of catalysts. The development of carbon-based nanostructured materials (i.e., activated carbon, carbon nitride, graphite, fullerenes, carbon nanotubes, diamond, graphene, etc.) represents an admirable substitute to out-of-date catalysts. Significant efforts have been made by researchers toward the improvement of various carbon-based metal nanostructures as catalysts. Moreover, incredible development has been achieved in several fields of catalysis, such as visible-light-induced catalysis, electrochemical performance, energy storage, and conversion, etc. This review gives an overview of the up-to-date developments in the strategy of design and fabrication of carbon-based metal nanostructures as photo-catalysts by means of several methods within the green approach, including chemical synthesis, in situ growth, solution mixing, and hydrothermal approaches. Moreover, the photocatalytic effects of the resulting carbon-based nanostructure classifications are similarly deliberated relative to their eco-friendly applications, such as photocatalytic degradation of organic dye pollutants.

Nanoparticle-Based Drugs: A Potential Armamentarium of Effective Anti-Cancer Therapies

BACKGROUND

Cancer is a foremost cause of mortality worldwide. Available treatments are non-specific and cannot cross biological barriers, which have restricted their usages. Furthermore, the side effects of existing treatments have promoted the exploration of nanotechnological approaches to achieve site-specific drug delivery. The diminutive sizes of nanoparticles, and hence, their large surface to volume ratios, means they are inherently more efficient at delivering drugs to specific tumor sites. This review highlights different approaches to cancer therapy, and the importance of nanoparticles in cancer therapy. Applications and limitations of different types of nanomedicines used for cancer imaging and treatment are discussed.

METHODS

We undertook extensive literature search of bibliographic databases (e.g. PubMed, Google Scholar, Medline, Web of Science etc.) using different keywords and combination of keywords to retrieve the relevant information.

RESULTS

This review provides overview of cancer and need for nanoparticle-based therapies for their treatment, and deliberates the different types of nanomaterials used as nanomedicines for cancer imaging and treatment in addition to their applications and limitations. Furthermore, applications of nanoparticles in modern cancer therapies and research strategies have been explored to overcome cancer.

CONCLUSION

Nanotechnology has provided a lot of novel therapeutics for the diagnosis and treatment of different cancers over the last 2-3 decades. However, there are few limitations of nanotechnological based anti-cancer therapies. Nanotechnology is enabling novel, specialized treatments for cancer; this will be a high-impact area of nanomedicine yielding more medical advancements with the next 10 years.

Increasing knowledge of home based maternal and newborn care using self-help groups: Evidence from rural Uttar Pradesh, India

BACKGROUND

In India, pregnant women and recently delivered mothers of marginalized communities in Uttar Pradesh (UP) remain un-reached by frontline-health-workers. In these communities, self-help groups (SHGs) have the potential to reach these women with knowledge of home-based maternal and newborn care (HBMNC).

OBJECTIVE

The study examines the feasibility of SHGs to improve knowledge of HBMNC. The study identifies the facilitating factors and barriers to knowledge change.

METHODS

A panel study with a quasi-experimental design was conducted in Jhansi, UP. Peer educators, called Swasthya Sakhi, of the SHGs of the experimental area were trained on how to conduct discussions on HBMNC topics. Both at baseline and endline 233 women from the experimental area and 237 women from the comparison area were interviewed to measure their knowledge change in HBMNC topics. The net-effect of the intervention was examined using difference-in-difference (DID) analysis with propensity-score-matching (PSM) controlling for the effect of background characteristics of the participants from two study areas. Generalized-estimating-equation (GEE) was used to identify the facilitating factors and barriers to the knowledge change.

RESULTS

The findings show significant net-increases in women's knowledge for most of the HBMNC topics including danger signs for a pregnant mother and a newborn child, even after controlling for the background characteristics of the participants. The most significant determinant of the increase of knowledge was the women's education.

CONCLUSION

Findings from the study showed SHGs can increase HBMNC knowledge among women. However, studies with longer duration are required to examine the scalability and sustainability of the intervention.

Mobile Phone Messaging to Husbands to Improve Maternal and Child Health Behavior in India

Over 90% of households in rural Uttar Pradesh, the most populous state of India, have at least one mobile phone. However, ownership of mobile phone among women is quite low. Implementation research was conducted in Uttar Pradesh to examine (a) whether providing information on selected maternal and child health (MCH) behaviors to a husband's mobile phone would enhance the man's knowledge and lead to discussions in their family, and (b) whether such discussions would help in the adoption of healthy practices. The m-Health intervention included biweekly voice messages in local language (Hindi) on MCH topics to the mobile phone of pregnant women's husbands. Using a quasi-experimental design, after four months of the m-Health intervention, in 2014, 881 husbands and 956 women from the study area were interviewed. Husbands' knowledge, controlling for their socio-demographic characteristics, were significantly higher among the listeners of the messages than the non-listeners. Multivariate logistic regression analysis showed that if husbands discussed the messages with family members, the odds of wives' practicing health behaviors improved significantly for three behaviors. These include one antenatal checkup in last trimester of pregnancy (odds ratio 1.72, p < 0.05), receiving a postnatal checkup within 7 days of delivery (odds ratio 3.02, p < 0.05), and delayed bathing of newborn (odds ratio 1.93, p < 0.05). Thus, communicating messages using m-Health was found to be an effective intervention for behavior change. The study demonstrated that mobile phones can be used effectively to reach men with MCH information and encourage them to promote healthy behavior in their family.

Recent progress of metal-graphene nanostructures in photocatalysis

Metal-graphene nanostructures (NSs) as photocatalysts, prepared using simple and scalable synthesis methods, are gaining heightened attention as novel materials for water treatment and environmental remediation applications. Graphene, the unique few layers sheet-like arrangement of sp2 hybridized carbon atoms, has an inimitable two-dimensional (2D) structure. The material is highly conductive, has high electron mobility and an extremely high surface area, and can be produced on a large scale at low cost. Accordingly, it has been considered as an essential base component for producing various metal-based NSs. In particular, metal-graphene NSs as photocatalysts have attracted considerable attention because of their special surface plasmon resonance (SPR) effect that can improve their performance for the removal of toxic dyes and other pollutants. This review summarizes the recent and advanced progress for the easy fabrication and design of graphene-based NSs as photocatalysts, as a novel tool, using a range of approaches, including green and biogenic approaches.

Microbial fuel cell assisted band gap narrowed TiO2 for visible light-induced photocatalytic activities and power generation

This paper reports a simple, biogenic and green approach to obtain narrow band gap and visible light-active TiO2 nanoparticles. Commercial white TiO2 (w-TiO2) was treated in the cathode chamber of a Microbial Fuel Cell (MFC), which produced modified light gray TiO2 (g-TiO2) nanoparticles. The DRS, PL, XRD, EPR, HR-TEM, and XPS were performed to understand the band gap decline of g-TiO2. The optical study revealed a significant decrease in the band gap of the g-TiO2 (E g  = 2.80 eV) compared to the w-TiO2 (E g  = 3.10 eV). The XPS revealed variations in the surface states, composition, Ti4+ to Ti3+ ratio, and oxygen vacancies in the g-TiO2. The Ti3+ and oxygen vacancy-induced enhanced visible light photocatalytic activity of g-TiO2 was confirmed by degrading different model dyes. The enhanced photoelectrochemical response under visible light irradiation further supported the improved performance of the g-TiO2 owing to a decrease in the electron transfer resistance and an increase in charge transfer rate. During the TiO2 treatment process, electricity generation in MFC was also observed, which was ~0.3979 V corresponding to a power density of 70.39 mW/m2. This study confirms narrow band gap TiO2 can be easily obtained and used effectively as photocatalysts and photoelectrode material.

Environmentally sustainable biogenic fabrication of AuNP decorated-graphitic g-C3N4 nanostructures towards improved photoelectrochemical performances

Proposed schematic model for the biogenic synthesis of Au-g-C₃N₄ nanostructures using an environment-friendly approach.

Conditional and Unconditional Cash Transfers to Improve Use of Contraception in Low and Middle Income Countries: A Systematic Review

This systematic review synthesizes evidence on the impact of conditional and unconditional cash transfers (CCT and UCT) on contraception in low- and middle-income countries. Scientific and gray literature databases were searched from 1994 to 2016 and 11 papers from ten studies were included. Most of the studies had low risk of bias. Cash transfers were used for increasing school attendance or improving health and nutrition, but not directly for contraception. Three studies showed positive impact on contraceptive use and four showed a decrease in fertility outcomes. An increase in childbearing was observed in two studies, and three studies demonstrated no impact on fertility indicators. All studies treated contraceptive use or fertility only as unintended and indirect outcomes. The available evidence on impact of CCT and UCT on contraception is inconclusive due to the limited number of studies, varying outcome measures, and lack of intervention specifically for contraception.

Gender-Based Violence in Rural Uttar Pradesh, India: Prevalence and Association With Reproductive Health Behaviors

This study explores the prevalence of different forms of domestic violence and their impact on women's reproductive health behavior in rural Uttar Pradesh (UP), India. Data were collected as a part of a large household survey carried out in 2009-2010. A multistage stratified systematic sampling design was used. A total of 4,223 married women aged 15 to 49 years and 2,274 husbands of these women were interviewed. Data were analyzed using bivariate and multivariate analyses. More than one third of married women in rural UP had experienced one or more forms of violence, such as verbal abuse, physical manhandling, and sexual abuse by their spouse. Nearly 47% of the women had experienced some form of violence during their last pregnancy. Significant associations were found between violence and incorrect reproductive health behaviors, pregnancy complications, poor birth preparedness, poor likelihood of institutional delivery, limited postnatal care, and limited spousal communication for family planning. After controlling for socio-economic variables in multivariate analysis, only pregnancy complications (odds ratio [OR] = 1.62, 95% confidence interval [CI] = [1.40, 1.85]) and lack of delivery preparedness (OR = 0.79, 95% CI = [0.68, 0.93]) were found to be significantly associated with violence. Husband's attitude and reporting of violence by their wives in different situations were not significantly associated. This study provides evidence of the association of violence on the reproductive health behavior of married women in rural India. The results argue for frontline health workers to identify and counsel pregnant women experiencing violence during antenatal check-up to reduce maternal morbidity and mortality.

CdS-graphene Nanocomposite for Efficient Visible-light-driven Photocatalytic and Photoelectrochemical Applications

This paper reports cadmium sulphide nanoparticles-(CdS NPs)-graphene nanocomposite (CdS-Graphene), prepared by a simple method, in which CdS NPs were anchored/decorated successfully onto graphene sheets. The as-synthesized nanocomposite was characterized using standard characterization techniques. A combination of CdS NPs with the optimal amount of two-dimensional graphene sheets had a profound influence on the properties of the resulting hybrid nanocomposite, such as enhanced optical, photocatalytic, and photo-electronic properties. The photocatalytic degradation ability of the CdS-Graphene nanocomposite was evaluated by degrading different types of dyes in the dark and under visible light irradiation. Furthermore, the photoelectrode performance of the nanocomposite was evaluated by different electrochemical techniques. The results showed that the CdS-Graphene nanocomposite can serve as an efficient visible-light-driven photocatalyst as well as photoelectrochemical performance for optoelectronic applications. The significantly enhanced photocatalytic and photoelectrochemical performance of the CdS-Graphene nanocomposite was attributed to the synergistic effects of the enhanced light absorption behaviour and high electron conductivity of the CdS NPs and graphene sheets, which facilitates charge separation and lengthens the lifetime of photogenerated electron-hole pairs by reducing the recombination rate. The as-synthesized narrow band gap CdS-Graphene nanocomposite can be used for wide range of visible light-induced photocatalytic and photoelectrochemical based applications.

Fabrication of WO3 nanorods on graphene nanosheets for improved visible light-induced photocapacitive and photocatalytic performance

Visible light-induced photocatalytic degradation of organic pollutants using WO₃ nanorods–graphene nanocomposite.

Challenges in Introducing New Contraceptive Methods: A Case Study of India

Increasing choice and introducing new contraceptive methods in the National Family Welfare Program in India could play a significant role in increasing adoption of contraception and meeting the unmet need of a large proportion of couples. However, inclusion of any new contraceptive method in India has to face many challenges at different steps: from clinical trials, administrative processes, acceptance in the national program, and reaching the intended beneficiaries. Having a good product is necessary but not sufficient for widespread accessibility, acceptance, and use. This article reviews the challenges based on the available policy documents, literature review, and discussions with senior program managers of the Ministry of Health and Family Welfare and development organizations. It concludes that comprehensive strategic planning is needed to address all possible barriers to ensure new contraceptive access at an affordable price by the beneficiaries it is intended for.

Visible light-induced enhanced photoelectrochemical and photocatalytic studies of gold decorated SnO2nanostructures

Visible light-induced photocatalytic degradation of colored dyes using Au–SnO₂nanocomposite.

Green synthesis, photocatalytic and photoelectrochemical performance of an Au–Graphene nanocomposite

Visible light-induced photocatalytic degradation of pollutants using an Au–Graphene nanocomposite.

Biogenic synthesis of a Ag–graphene nanocomposite with efficient photocatalytic degradation, electrical conductivity and photoelectrochemical performance

Visible light-driven photocatalytic degradation of organic pollutants using the Ag–graphene nanocomposite.

Medical barriers to emergency contraception: a cross-sectional survey of doctors in North India

BACKGROUND

Some medical doctors in India have publicly expressed opposition to making emergency contraceptive pills (ECPs) easily accessible, even though ECPs are included in the method mix of the Ministry of Health and Family Welfare program and as an over-the-counter (OTC) product. Such opposition affects access to ECPs by influencing policy, procurement, and distribution, besides stigmatizing the ECP user. This study was conducted to assess ECP knowledge, attitudes, and practices of doctors in North India.

METHODS

A cross-sectional survey of 83 doctors who provide ECPs, randomly selected from 3 cities in the state of Uttar Pradesh, was conducted in 2011. The quantitative data were complemented by 19 in-depth interviews with purposively selected senior gynecologists and other opinion leaders.

RESULTS

All surveyed physicians cited the correct dose and regimen for ECPs. However, the large majority of those surveyed believed that ECPs work by preventing implantation. (The best evidence currently indicates that ECPs do not work by preventing implantation.) Most doctors also believed incorrectly that ECPs have several contraindications and side effects. They also had strong reservations against OTC provision of ECPs by pharmacists and community health workers (CHWs) and negative attitudes toward ECP users, which serve as serious medical barriers to mainstreaming use of ECPs.

CONCLUSION

Physicians and their professional associations exert a strong influence on the operationalization of national contraceptive policies. Evidence-based advocacy and educational campaigns targeting doctors are needed to address and resolve their reservations about ECPs, particularly about its provision as an OTC product and its distribution by CHWs. Partnerships with medical associations can help reduce doctors' negative attitudes and create a conducive environment for influencing clinical practices. Such changes are needed to increase the availability and use of ECPs as part of a package of a full range of contraceptive method options to prevent unwanted pregnancy among the most vulnerable populations.

Promoting healthy spacing between pregnancies in India: need for differential education campaigns

OBJECTIVE

Birth spacing intervals are relatively short in India. Healthy spacing of 3-5 years between births is an effective way to prevent maternal and child mortality and morbidities. Socio-cultural and structural barriers, including limited awareness, socio-cultural norms, and misconceptions need to be addressed for behavior change. Hence the objective was to understand these barriers and accordingly develop separate messages for young women, her husband and her mother-in-law.

METHODS

Data were collected from young women, husbands and mothers-in-law using qualitative methods. Altogether 16 Focus Group Discussions and 30 in-depth interviews were conducted. Beliefs related to need of spacing, disadvantages of closely spaced pregnancies and messages considered suitable for different stakeholders were investigated. Messages were identified for women, husband and mother-in-law; communication aids prepared and community workers trained to appropriately communicate the messages to stakeholders. Quantitative data were collected to measure the effect of the intervention.

RESULTS

Educational campaign resulted in higher use of contraceptives for spacing among registered pregnant women from experimental area compared to control area.

CONCLUSION

Differential audience specific educational campaign is feasible and effective.

PRACTICE IMPLICATIONS

For an effective communication in the community, workers should know how exactly to convey the different health messages to different target population.

Achieving the Cairo Conference (ICPD) goal for youth in Bangladesh

Sexual and reproductive health education is not yet formally introduced in Bangladesh without which the International Conference on Population and Development (ICPD) in Cairo's goal to ensure young people's right to access to such information and services will remain unfulfilled. The Population Council provided technical assistance to a governmental department to pilot youth reproductive health education. Study findings from the pre- and posttests of 379 matched respondents revealed significant changes in knowledge, attitudes, and life-skills. Knowledge about long-term contraceptives and skills on negotiating safe sex improved significantly by 63% and 26%, respectively. Youths who do not consider menstruation as a disease nearly doubled, and misunderstandings about the mother's role in sex determination of a child were significantly dispelled. Decisions not to accompany friends in visiting sex workers and to use condoms, ignoring friends' disapproval, were increased over 18%. Over 98% of students reported that teachers discussed condoms, while only 12% alleged unfriendly behavior. Findings motivated the department to scale up the reproductive health curriculum.

Safer maternal health in rural Uttar Pradesh: do primary health services contribute?

India accounts for about one-quarter of maternal deaths world wide, with the most recent statistics showing an average maternal mortality ratio of 407 per 100 000 live births at the national level. The government had hoped to reduce maternal mortality to 200 by 2000, but it is clear that this was not achieved. This paper explores the reasons why the most populous state of Uttar Pradesh continues to have one of the highest reported maternal mortality ratios in India. Data from two districts of Uttar Pradesh on mother and child health-care utilization and the readiness of the public sector to provide antenatal and emergency obstetric services are used to illustrate the reasons why maternal mortality has not declined. While blueprints for safe motherhood programmes exist, the equipment and technical competence to provide services is weak at the present moment. Reductions in maternal mortality would require interventions to improve service delivery as well as community mobilization to improve utilization of services, especially in life-threatening situations.

A comparison of 1970 and 1980 survey findings on family planning in India

This report compares the findings of two national sample surveys and highlights changes in the level of knowledge, attitude, and practice of family planning among Indian couples during 1970-1980. No significant change in desired family size during this period is indicated, but awareness about various contraceptives increased and more people had a favorable attitude toward family planning by 1980. However, about 45 percent of all couples who participated in the 1980 survey were unfamiliar with sterilization as a family planning method. About 60 percent did not know how to use condoms. The corresponding percentages for IUDs and the pill were even higher--about 80 percent in each case. Nevertheless, use of modern contraceptives increased from 10 percent in 1970 to 28 percent in 1980. The proportion of couples depending on traditional methods, primarily rhythm, was substantial and increased from 4 percent in 1970 to 7 percent in 1980. Sterilization remained the most popular modern method, followed by condoms. It was also found that current contraceptive users belonged to a relatively better socioeconomic group than those couples who did not want any additional children yet were not practicing contraception, characterized by a higher literacy level, more exposure to mass media, and better communication between spouses.

Complex reflection coefficients for the parallel and perpendicular polarizations of a film-substate system

The complex reflection coefficients Rv(phi,zeta) of a film-substrate system for the parallel (v = p) and perpendicular (v = s) polarizations are examined in detail as functions of the angle of incidence phi(0 </+S 90 degrees) and the reduced normalized film thickness zeta(0 </= zeta </= 1). For definiteness, the reflection of light of wavelength lambda = 0.6328 microm by the air-SiO2-Si system is assumed. Families of circles that represent the constant-angle-of incidence contours, their envelopes, and the associated constant-thickness contours of Rv, and Rs are all presented in the complex plane. Furthermore, the amplitude-reflectance and phase-shift functions, Rv (phi, zeta) and argRv(phi, zeta), are plotted vs zeta with phi constant and vs phi with zeta constant. It is shown that Rp or Rs can assume the same complex value at two different angles of incidence (i.e., the film-substrate system can have identical reflection characteristics for a given polarization at two angles) for certain ranges of film thickness. The distinct case of internal reflection is represented by a separate example.

Polarization-preserving single-layer-coated beam displacers and axicons

A design procedure is described to determine the thicknesses of single-layer coatings of a given dielectric on a given metallic substrate so that any input polarization of light is preserved after two reflections at the same angle of incidence from a parallel-mirror beam displacer or an axicon. This is achieved by equalizing the net complex p and s reflection coefficients (also called the radial and azimuthal eigenvalues of an axicon) after two reflections. The net polarization-independent reflectance (insertion loss) of the device is computed and found to exceed the net minimum parallel reflectance of the uncoated device for incidence above a certain angle. Thus the dielectric films serve (1) protective, (2) polarization-corrective, and (3) reflectance-enhancement functions simultaneously. The sensitivity of the designs (deviation from the condition of polarization preservation) to small film-thickness and angle-of-incidence errors is examined. Results are presented graphically and in tables of applications of the method to beam displacers and axicons for He-Ne laser light, lambda = 0.6328 microm, using Al(2)O(3) (or Si(2)O(3))/Al and MgF(2)/Al film-substrate systems, and for CO(2) laser light, lambda = 10.6 microm, using ZnS or ThF(4) films on an Ag substrate.