Mn-Modified ZnO Nanoflakes for Optimal Photoelectrochemical Performance Under Visible Light: Experimental Design and Theoretical Rationalization.

Doping of zinc oxide (ZnO) with manganese (Mn) tunes midbandgap states of ZnO to enhance its optical properties and makes it into an efficient photoactive material for photoelectrochemical water splitting, waste removal from water, and other applications. We demonstrate that ZnO modified with 1 at. % Mn exhibits the best performance, as rationalized by experimental, structural, and optical characterization and theoretical analysis. ZnO doped with the optimal Mn content possesses improved light absorption in the visible region and minimizes charge carrier recombination. The doping is substitutional and creates midgap states near the valence band. Mn atoms break localized charge traps at oxygen vacancy sites and eliminate photoluminescence peaks associated with oxygen vacancies. The optimal performance of Mn-modified ZnO is demonstrated with the photodegradation of Congo red and photoelectrochemical water splitting.

Enhancement of Photocatalytic and Photoelectrochemical Performance of ZnO by Mg Doping: Experimental and Density Functional Theory Insights.

Doped ZnO nanostructures have shown great potential for solar energy applications. Considering the compatible ionic radius, Mg atoms can be doped into ZnO at different concentrations. The current work reports a combined experimental and density functional theory study on the influence of the Mg dopant concentration on ZnO performance simultaneously for photocatalytic dye removal and photoelectrochemical water splitting. Among all the samples, Mg(3)-ZnO (3 at. % Mg) exhibits superior sunlight-driven photocatalytic performance. The optimal Mg-ZnO shows an 8-fold increase in the photocatalytic activity compared to the pristine ZnO. Likewise, the most active photocatalyst shows high photoelectrochemical performance with a photocurrent response of 1.54 mA at the lowest onset potential, 11 times higher than the pristine ZnO. Tuning of the Mg content results in the generation of extra charge carriers and a reduced recombination rate, which are the crucial factors responsible for enhanced photocatalytic and photoelectrochemical performance.

Effects of HCN2 Mutations on Dendritic Excitability and Synaptic Plasticity: A Computational Study.

Several reports of augmented hyperpolarisation-activated cyclic nucleotide-gated (HCN) currents in seizures have suggested a pro-convulsive identity for HCN channels. The mutations identified in one or more of the four HCN channel subunits are found to be contributing to different epileptic phenotypes. S126L, S632W, V246M and E515K are four different mutations affecting the HCN2 subunit and have been reported in febrile seizures and partial/generalised idiopathic epilepsies. From the visible outcomes in subjects with these mutations, it is evident that they must play important roles in altering dendritic excitability. Through this simulation study using NEURON, we created a three-compartmental, hippocampal CA1 pyramidal neuron synapse model expressing seven different ion channels (fast sodium (NaF), T-type calcium (CaT), R-type calcium (CaR), delayed rectifier potassium (KDR), A-type potassium (KA), small conductance potassium (SK), and HCN channels) and two glutamate receptors (AMPAR and NMDAR). We modelled an HCN2 channel and incorporated changes in it to obtain mutation kinetics. Their effects on excitability were studied by observing resting membrane potentials, input resistances and plasticity profiles for measuring the sliding modification threshold (SMT) of Bienenstock-Cooper-Munro (BCM) theory. Virtual knockouts of ion channels other than HCN were also performed to assess their role in altering excitability when they act alongside HCN2 mutations. Our results show that HCN2 mutations can potentially be a primary causative factor for excessive action potential firing through their effect on resting membrane potentials and input resistance.

A Potential Biomarker in Amyotrophic Lateral Sclerosis: Can Assessment of Brain Iron Deposition with SWI and Corticospinal Tract Degeneration with DTI Help?

BACKGROUND AND PURPOSE: Iron-mediated oxidative stress plays a pivotal role in the pathogenesis of amyotrophic lateral sclerosis. This study aimed to assess iron deposition qualitatively and quantitatively by using SWI and microstructural changes in the corticospinal tract by using DTI in patients with amyotrophic lateral sclerosis. MATERIALS AND METHODS: Seventeen patients with amyotrophic lateral sclerosis and 15 age- and sex-matched controls underwent brain MR imaging with SWI and DTI. SWI was analyzed for both signal-intensity scoring and quantitative estimation of iron deposition in the anterior and posterior banks of the motor and sensory cortices and deep gray nuclei. The diffusion measurements along the corticospinal tract at the level of pons and medulla were obtained by ROI analysis. RESULTS: Patients with amyotrophic lateral sclerosis showed reduced signal-intensity grades in the posterior bank of the motor cortex bilaterally. Quantitative analysis confirmed significantly higher iron content in the posterior bank of the motor cortex in patients with amyotrophic lateral sclerosis. In contrast, no significant differences were noted for the anterior bank of the motor cortex, anterior and posterior banks of the sensory cortex, and deep nuclei. Receiver operating characteristic comparison showed a cutoff of 35µg Fe/g of tissue with an area under the curve of 0.78 (P = .008) for the posterior bank of the motor cortex in discriminating patients with amyotrophic lateral sclerosis from controls. Fractional anisotropy was lower in the pyramidal tracts of patients with amyotrophic lateral sclerosis at the pons and medulla on either side, along with higher directionally averaged mean diffusivity values. The combination of SWI and DTI revealed an area under the curve of 0.784 for differentiating patients with amyotrophic lateral sclerosis from controls. CONCLUSIONS: Measurements of motor cortex iron deposition and diffusion tensor parameters of the corticospinal tract may be useful biomarkers for the diagnosis of clinically suspected amyotrophic lateral sclerosis.

Design improvement and performance evaluation of solar photocatalytic reactor for industrial effluent treatment.

This work reports the details of the design components and materials used in a linear compound parabolic trough reactor constructed with an aim to use the photocatalyst for solar photocatalytic applications. A compound parabolic trough reactor has been designed and engineered to exploit both UV and visible part of the solar irradiation. The developed compound parabolic trough reactor could receive almost 88% of UV radiation along with a major part of visible radiation. The performance of the reactor has been evaluated in terms of degradation of a probe pollutant using the parameters such as rate constant, residence time and photonic efficiency. An attempt has been made to assess the performance in different ranges of solar spectrum. Finally the developed reactor has been employed for the photocatalytic treatment of a paper mill effluent using Degussa P25 as the photocatalyst. The paper mill effluent collected from Nagaon paper mill, Assam, India has been treated under both batch mode and continuous mode using Degussa P25 photocatalyst under artificial and natural solar radiation, respectively. The photocatalytic degradation kinetics of the paper mill effluent has been determined using the reduction in total organic carbon (TOC) values of the effluent.

Machine learning methods for the classification of gliomas: Initial results using features extracted from MR spectroscopy.

CONTEXT: With the advent of new imaging modalities, radiologists are faced with handling increasing volumes of data for diagnosis and treatment planning. The use of automated and intelligent systems is becoming essential in such a scenario. Machine learning, a branch of artificial intelligence, is increasingly being used in medical image analysis applications such as image segmentation, registration and computer-aided diagnosis and detection. Histopathological analysis is currently the gold standard for classification of brain tumors. The use of machine learning algorithms along with extraction of relevant features from magnetic resonance imaging (MRI) holds promise of replacing conventional invasive methods of tumor classification. AIMS: The aim of the study is to classify gliomas into benign and malignant types using MRI data. SETTINGS AND DESIGN: Retrospective data from 28 patients who were diagnosed with glioma were used for the analysis. WHO Grade II (low-grade astrocytoma) was classified as benign while Grade III (anaplastic astrocytoma) and Grade IV (glioblastoma multiforme) were classified as malignant. METHODS AND MATERIALS: Features were extracted from MR spectroscopy. The classification was done using four machine learning algorithms: multilayer perceptrons, support vector machine, random forest and locally weighted learning. RESULTS: Three of the four machine learning algorithms gave an area under ROC curve in excess of 0.80. Random forest gave the best performance in terms of AUC (0.911) while sensitivity was best for locally weighted learning (86.1%). CONCLUSIONS: The performance of different machine learning algorithms in the classification of gliomas is promising. An even better performance may be expected by integrating features extracted from other MR sequences.

Enhanced visible light photocatalytic disinfection of gram negative, pathogenic Escherichia coli bacteria with Ag/TiV oxide nanoparticles.

Silver sensitized titanium vanadium mixed Ag/TiV oxide photocatalyst was synthesized using sol-gel technique. The catalyst was characterized using XRD, SEM, EDAX, HRTEM, UV-DRS, XPS, and PL analysis which reveal the formation of a predominantly rutile mixed phase nanoparticles of 25-30 nm crystallite size. The catalyst showed a marked red-shift in the absorption spectrum compared to Degussa P25. It exhibited a remarkable enhancement in the visible light photocatalytic activity in inactivating Escherichia coli, a gram-negative pathogenic bacterium, too. The conclusions are supported by a comparison with an identically synthesized TiV oxide sample. A microbicidal photonic efficiency (MPE) has been defined and a method for its determination has been proposed to facilitate quantification of the performance of the photocatalyst and the disinfection system taking into account the response of the catalyst to the radiation intensity.

Functional polymorphisms in the interleukin-6 and serotonin transporter genes, and depression and fatigue induced by interferon-alpha and ribavirin treatment.

Depression and fatigue are frequent side effects of interferon-alpha (IFN-alpha) treatment, and there is compelling evidence that the inflammatory response system (including interleukin-6, IL-6) and the serotonergic system is important in the pathophysiology of such symptoms. Functional polymorphisms in the promoter region of the IL-6 gene (rs1800795) and serotonin transporter gene (5-HTTLPR) have been identified as regulating these systems. The present study aimed to determine if these polymorphisms were associated with the development of depression and fatigue during IFN-alpha and ribavirin treatment. Ninety-eight Caucasian patients receiving pegylated IFN-alpha and ribavirin treatment for chronic hepatitis C virus at King's College Hospital, London, and Emory University Hospital, Atlanta, participated in this prospective cohort study. Symptoms of depression and fatigue were measured before treatment and at weeks 4, 8, 12 and 24 during treatment. The 'low IL-6' synthesizing genotype (CC) was associated with significantly fewer symptoms of depression (effect size = 0.7 at week 24; F = 9.4, d.f. = 436, P = 0.002). The 'high transcription' serotonin transporter (5-HTT) genotype (LL) was also associated with significantly fewer symptoms of depression, but with a much smaller effect (effect size = 0.2 at week 24; F = 4.5, d.f. = 436, P = 0.03). Neither polymorphisms were associated with symptoms of fatigue (IL-6: F = 1.2, d.f. = 430, P = 0.2; 5-HTT: F = 0.5, d.f. = 430, P = 0.5). The smaller effects of the 5-HTT polymorphism on depression may be explained by an interaction between the genes (F = 5.0, d.f. = 434, P = 0.02): the 'protective' effect of the 5-HTTLPR polymorphism was evident only in the presence of the 'low IL-6' genotype (F = 5.4, d.f. = 64, P = 0.02), not in the presence of the 'high IL-6' genotype (F = 2.2, d.f. = 369, P = 0.1). The association between the IL-6 polymorphism and reduced risk of depressive symptoms confirms the role of the inflammatory response system in the pathophysiology of IFN-alpha-induced depression; in contrast, the effect of the 5-HTT gene was small and perhaps dependent on the status of the inflammatory response.

Characteristics of high intent suicide attempters admitted to a general hospital.

BACKGROUND: Suicide intent is a strong predictor of repetition of attempts and subsequent suicide. This study aimed to compare socio-demographics, clinical factors and method of attempt in high and low intent suicide attempters. METHOD: All patients admitted following attempted suicide to a teaching hospital were interviewed. Socio-demographic information, details of the attempt and psychiatric diagnosis were recorded. Scales for assessing suicide intent, lethality, recent life-events and depression were administered. Comparison between high intent and low intent groups were done to identify the characteristics of patients who had high suicidal intent. RESULTS: The sample comprised 203 patients, 84 of whom were classified as high intent attempters using the Suicide Intent Scale. The high intent group were significantly more likely to be male (p = 0.01), of single marital status (p = 0.04), have a psychiatric diagnosis, especially depression (p = 0.001) and use self immolation to attempt suicide (p = 0.001). Patients with high intent had significantly higher lethality (p = 0.001) and recent stressful life-event scores (p = 0.001). CONCLUSIONS: High intent suicide attempts are associated with distinct socio-demographic profiles and psychiatric morbidity. Routine assessment of intent may help to identify individuals with high risk, who can be offered targeted interventions.

Salt wasting disorder in the newborn.

The clinical presentation of pseudohypoaldosteronism (PHA) mimics congenital adrenal hyperplasia (CAH). Poor response of the dehydration and electrolyte abnormalities to steroid therapy should make one suspect PHA. The treatment is supportive in the form of salt replacement and sodium resonium. We report a case of PHA that presented as salt wasting on the second day of life, initially appearing like CAH. The baby responded well to sodium resonium and salt replacement.

Epidemiology of chronic fatigue syndrome.

BACKGROUND: Chronic fatigue syndrome (CFS) is a controversial disorder with different case definitions, aetiological models and proposed treatments. An epidemiological approach is likely to bring some clarity to the field. AIM: The aim of this article is to review the literature on the epidemiology of fatigue, chronic fatigue and CFS. METHOD: A literature search was conducted using the databases Medline and Pubmed as well as the reference lists of recent reviews to identify the relevant studies. The aim was not to do a systematic review but to review the key studies in the area to highlight the methodological issues. RESULTS: The review is organized according to the following areas: the prevalence of fatigue and chronic fatigue, the prevalence and incidence of CFS, epidemiological associations such as gender, social class and psychiatric co-morbidity and CFS in special groups such as those recovering from a viral infection, specific occupational groups and Gulf War veterans. CONCLUSION: While fatigue as a symptom is very common, CFS is relatively rare. Many of the epidemiological associations seen in specialist clinics are not found in community samples. It is unlikely that one specific causal factor can explain CFS. Future studies should go beyond estimating the prevalence to testing more complex aetiological models.

A questionnaire survey of psychiatrists attitudes towards genetic counselling.

Genetic counselling in psychiatry aims at facilitating mentally ill patients and their relatives to make informed choices after understanding what is known about the genetics of a given mental disorder This area of practice is a recent development in mental health care. This study surveyed the attitudes and practices of Indian psychiatrists towards genetic counselling. Fifty-nine out of 150 randomly selected psychiatrists completed a semi-structured questionnaire assessing various aspects of genetic counselling in practice.The results show that there is a felt need for genetic counselling among patients. Most of the respondents provide information regarding the hereditary nature and risk of inheritance of mental illnesses in single sessions of less than 30 minutes duration in clinical situations. Most psychiatrists (76%) felt that genetic counselling is feasible in practice, but 24% felt inadequate knowledge, illiteracy among patients and time constraints as some hindering factors for the same. Genetic counselling was considered to be important in planning management for patients by most respondents. The need to improve their knowledge and skills in the genetic understanding of mental illnesses was also reported. These results have implications for future practice of genetic counselling in the Indian setting.