Ultrasensitive and reversible NO2 gas sensor based on SnS2/TiO2 heterostructures for room temperature applications

Nitrogen dioxide (NO2) is one of the toxic gases produced by chemical industries, power plants, and vehicles. In this work, we demonstrate an inexpensive sensing platform for NO2 detection at room temperature (RT-32 °C) based on a charge transfer mechanism. Three-dimensional hierarchical SnS2 and SnS2/mesoporous TiO2 nanocomposites were synthesized via the solvothermal method. SnS2/20 wt% mesoporous TiO2 nanocomposites sample showed 245.4% enhanced response compared to pristine SnS2. The fabricated device exhibits excellent selectivity among all other interfering gases with one-month stability. The rapid response and enhanced response achieved were obtained for the minimum concentration of 2 ppm NO2. The formation of heterojunction between SnS2 and mesoporous TiO2 has a synergetic effect, providing more active sites and porous structures for the detection of NO2 gas molecules.

Automatic recognition of lung tumor using convolutional neural networks

The unchecked proliferation of abnormal cells in the lung is known as lung cancer, and it is one of the major causes of death globally. The most accurate way for finding malignant lung nodules is a thorax Computed Tomography (CT) scan. A spherical lesion called a lung nodule can either be malignant or not. Lung cancer appears as rounded, white shadow nodules on the CT scan. The candidate ROIs are calculated using existing method and some blood vessels are removed using rule-based methods based on the candidate ROIs' shape features. Next, the candidate ROIs' remaining grey and texture features are calculated, and are given to the classifier to categorize the candidates. The rule-based technique has no omissions, according to experimental results, however the misclassification probability is too high. Therefore, in the proposed method, by computing the texture features from the Grey Level Co-occurrence Matrix (GLCM) in the wavelet domain, the nodules were identified and CT images were categorized using Convolutional Neural Networks (CNN) into two groups: those with and those without malignant lung nodules. In this work, two classifiers Support Vector Machine (SVM) and CNN are used for the recognized lung cancer image to determine the severity of the condition. Comparisons between SVM and CNN classifiers are done with regard to quality parameters including accuracy and sensitivity.

Overview of diagnostics on a small-scale RF source for fusion (ROBIN) and the one planned for the diagnostic beam for ITER

India is responsible for the supply of diagnostic neutral beam systems for ITER to diagnose its helium ash during the deuterium-tritium plasma phase using the charge exchange recombination spectroscopy technique. Considering the many first of its kind in terms of technologies and beam development aspects, ITER Indian domestic agency has adopted a strategy of developing the technology and beam experimentation in parallel. On the beam development front three test beds, namely, the ROBIN (Rf Operated Beam source in India for Negative ion research), the TWIN (TWo rf driver-based Indigenously built Negative ion source), and the INTF (INdian Test Facility) are presently in their various phases of operation, optimization, and setting up at IPR, respectively. Experiments related to plasma production, beam production, and acceleration up to 30 keV in volume and surface mode have been performed on ROBIN. The maximum negative hydrogen ion current density to a tune of 27 mA/cm² is obtained in the surface mode with Cs injection. Optimal source performance requires optimal surface conditions, minimum impurities, careful characterization of the plasma, cesium feed and its redistribution, and optimal wall temperatures of the surfaces of the plasma box and the plasma grid. A combination of probe, optical, vacuum, laser based, electrical, and calorimetric diagnostic measurements enables such a control. At ROBIN, the above diagnostics are being used regularly. The operational and diagnostic experiences on ROBIN shall provide the desired experience and database for operations of TWIN and INTF in the coming years. A large number of conventional and advanced diagnostic techniques are used for plasma and beam characterization. These diagnostics are suitable not only to detect and understand the plasma but also for studies related to impurity evolution. The temporal evolution of impurities significantly impacts the plasma and beam properties. The studies help in establishing correlations between physical parameters and operational parameters to optimize the source performance ensuring adequate safety and investment protection. This paper will present a brief overview of various diagnostics implemented, lessons learned, and the results obtained from ROBIN. In addition, an outline of the diagnostics planned for INTF based on the experience and understandings developed during the present experiments on ROBIN and TWIN and considering the requirements of large systems shall be discussed.

Interface enriched highly interlaced layered MoS2/NiS2 nanocomposites for the photocatalytic degradation of rhodamine B dye

In the past few decades, air and water pollution by organic dyes has become a serious concern due to their high toxicity. Removal of these organic dyes from polluted water bodies is a serious environmental concern and the development of new advanced photocatalytic materials for decomposing organic dyes can be a good solution. In this work, layered molybdenum disulfide/nickel disulfide (MoS₂/NiS₂) nanocomposites with various NiS₂ content was synthesized by a one-step hydrothermal method using citric acid as a reducing agent. The X-ray diffraction pattern shows the hexagonal and cubical crystal structure of MoS₂ and NiS₂, respectively. Morphological analysis confirms the formation of MoS₂/NiS₂ nanosheets. The elemental composition of the samples was carried out by XPS, which shows a significant interaction between NiS₂ and MoS₂. The photocatalytic performance of MoS₂/NiS₂ nanocomposites was studied by the degradation of rhodamine B (RhB). Ni-4 sample shows higher photocatalytic activity with a maximum degradation of 90.61% under visible light irradiation for 32 min.

The photocatalytic performance of MoS₂/NiS₂ nanocomposites was studied by the degradation of rhodamine B (RhB). Ni-4 sample shows higher photocatalytic activity with a maximum degradation of 90.61% under visible light irradiation for 32 min.

P300 and neuropsychological measurements in patients with schizophrenia and their healthy biological siblings

BACKGROUND

Patients with schizophrenia and their first-degree relatives' exhibit abnormalities in neuropsychological and electrophysiological measures especially P300. The aim was to study the P300 and neuropsychological measures together in patients with schizophrenia, their unaffected siblings, and normal controls.

MATERIALS AND METHODS

Thirty patients diagnosed as schizophrenia, their unaffected biological siblings, and normal controls were included in the study. Inpatient group, the severity of symptoms was assessed by Positive and Negative Syndrome Scale. All subjects were administered P300 event-related potential, which was measured using oddball paradigm and specific neuropsychological tests from NIMHANS neuropsychiatry battery.

RESULTS

Both patients with schizophrenia and their unaffected biological siblings showed lower P300 amplitude and longer P300 latency when compared with the normal controls. The three groups showed statistically significant differences in digit symbol substitution test, digit vigilance test, Trail making test B and Stroop test (P < 0.001).

CONCLUSION

Patients with schizophrenia and their unaffected biological siblings show deficits in both cognitive function tests and P300 event-related potential. Our results suggest a continuum in the electrophysiological and neuropsychological measures among the three groups.

Characteristics of the positive ion source at reduced gas feed

The neutral beam injector of steady state superconducting tokamak (SST1-NBI) at IPR is designed for injecting upto 1.7 MW of neutral beam (Hº, 30-55 keV) power to the tokamak plasma for heating and current drive. Operations of the positive ion source (PINI or Plug-In-Neutral-Injector) of SST1-NBI were carried out on the NBI test stand. The PINI was operated at reduced gas feed rate of 2-3 Torr l/s, without using the high speed cryo pumps. Experiments were conducted to achieve a stable beam extraction by optimizing operational parameters namely, the arc current (120-300 A), acceleration voltage (16-40 kV), and a suitable control sequence. The beam divergence, power density profiles, and species fractions (H(+):H2(+):H3(+)) were measured by using the diagnostics such as thermal calorimetry, infrared thermography, and Doppler shift spectroscopy. The maximum extracted beam current was about 18 A. A further increase of beam current was found to be limited by the amount of gas feed rate to the ion source.

A Study of Certain Herbs Against Chlorpyrifos-induced Changes in Lipid and Protein Profile in Poultry

A total of 225 male broiler chicks (Cobb strain) of day-old age were procured for the study. The chicks were randomly divided into 15 groups consisting of 15 chicks in each group. Group 1 was maintained as basal diet control and group 2 on chlorpyrifos (CPS) at 100 ppm in feed throughout 6 wk as iron toxic control without any treatment. Groups 3-15 were maintained on CPS at 100 ppm in feed for the 4 wk (28 days) of study and thereafter administered with different herbs and their combinations for remaining 2 wk. The blood samples were drawn from wing vein on 28^th day and 42^nd day from the birds in each group for the estimation of lipid and protein profiles. The birds were sacrificed at the end of 6^th week and liver tissues were collected for histological examination. The concentrations of total cholesterol, low density lipoprotein (LDL) cholesterol, triglycerides, total protein, albumin and globulins and the A/G ratio were increased significantly (P<;0.05) in toxic groups (2–15), while high density lipoprotein (HDL) cholesterol was significantly (P<;0.05) decreased at the end of 4^th week. However, following supplementation of herbs and herbal combinations, the values of lipid and protein profile in groups 3–15 revived toward normal at the end of 6^th week. Histopathology of liver in CPS toxic control (group 2) revealed areas of degeneration, while groups 3–15 that were treated with herbs and their combinations exhibited these changes in a milder form, indicating regenerative alterations. The study revealed that chorpyrifos-induced changes in lipid and protein profile were improved by supplementation of certain herbs.

Challenges associated with metal chelation therapy in Alzheimer's disease

A close association between brain metal dishomeostasis and the onset and/or progression of Alzheimer's disease (AD) has been clearly established in a number of studies, although the underlying biochemical mechanisms remain obscure. This observation renders chelation therapy an attractive pharmacological option for the treatment of this disease. However, a number of requirements must be fulfilled in order to adapt chelation therapy to AD so that the term "metal targeted strategies" seems now more appropriate. Indeed, brain metal redistribution rather than brain metal scavenging and removal is the major goal of this type of intervention. The most recent developments in metal targeted strategies for AD will be discussed using, as useful examples, clioquinol, curcumin, and epigallocatechin, and the future perspectives will also be outlined.

Mathematical approach to understand the kinetics of alpha-synuclein aggregation: relevance to Parkinson's disease

alpha-Synuclein aggregation is a hallmark pathological feature in Parkinson's disease (PD). The conversion of alpha-synuclein from soluble monomer to insoluble aggregates through the toxic oligomeric intermediates underlie the neurodegeneration associated with PD. Redox active metal ions such as iron (Fe) and copper (Cu) are known to enhance alpha-synuclein fibrillogenesis. In the present study, we have implemented mathematical approach to monitor the kinetics of aggregation of alpha-synuclein nucleation and elongation constants based on fluorescence studies. In this pretext, we have implemented mathematical simulations like self and absolute analysis. The mathematical model discussed in this paper is the first of its kind and might prove useful for predicting the drug intervention time to prevent alpha-synuclein aggregation and has future clinical application.

Light-Harvesting in Carbonyl-Terminated Phenylacetylene Dendrimers: The Role of Delocalized Excited States and the Scaling of Light-Harvesting Efficiency with Dendrimer Size

The photophysics of a family of conjugated phenylacetylene (PA) light-harvesting dendrimers are studied using steady-state and time-resolved optical spectroscopy. The dendrimers consist of a substituted PA core surrounded by meta-branched PA arms. The total number of PA moieties ranges from 3 (first generation) to 63 (fifth generation). By using an alcohol/ketone substituent at the dendrimer core, we avoid through-space Forster transfer from the peripheral PA donors to the core acceptor (in this case, the carbonyl group), which simplifies the analysis of these molecules relative to the perylene-terminated molecules studied previously. The delocalized excited states previously identified in smaller dendrons are seen in these larger dendrimers as well, and their influence on the intersite electronic energy transfer (EET) is analyzed in terms of a point-dipole Forster model. We find that these new delocalized states can both enhance EET (by decreasing the spatial separation between donor and acceptor) and degrade it (by lowering the emission cross section and shifting the energy, resulting in poorer spectral overlap between donor and acceptor). The combination of these two effects leads to a calculated intersite transfer time of 6 ps, in reasonable agreement with the 5-17 ps range obtained from experiment. In addition to characterizing the electronic states and intersite energy transfer times, we also examine how the overall light-harvesting efficiency scales with dendrimer size. After taking the size dependence of other nonradiative processes, such as excimer formation, into account, the overall dendrimer quenching rate k(Q) is found to decrease exponentially with dendrimer size over the first four generations. This exponential decrease is predicted by simple theoretical considerations and by kinetic models, but the dependence on generation is steeper than expected based on those models, probably due to increased disorder in the larger dendrimers. We discuss the implications of these results for dendrimeric light-harvesting structures based on PA and other chemical motifs.

Novel synthesis of cyclobutanone derivatives via dimetalation of iminium ions with the TiCl4-trialkylamine reagent system

Iminium salts are generated in situ, react with TiCl4-trialkylamines, and diaryl ketones to produce 3,3-diaryl-cyclobutanones in moderate to good yields.

Toward globular macromolecules with functionalized interiors: design and synthesis of dendrons with an interesting twist

[see reaction]. Design and synthesis of a novel class of monodendrons, in which the functional units can potentially be directed toward the concave interiors of dendrimers, are described. The key feature of the design is the placement of the amphiphilic and the AB2 functional groups in orthogonal planes.

Finger pulse volume in patients with panic attacks

To study the peripheral blood flow in patients with panic attacks during "Stress" conditions, nine patients with history of panic attacks were subjected to mental stress of arithmetic calculation and room-air voluntary hyperventilation. Finger Pulse Volume (FPV) was significantly altered during the period following mental activity in untreated patients when compared to controls and patients under treatment. There was also an increase in FPV in untreated patients at rest and during recovery after mental stress when compared to the treated patients.