Catalytic synergy of WS2-anchored PdSe2 for highly sensitive hydrogen gas sensor.

Hydrogen (H2) is widely used in industrial processes and is one of the well-known choices for storage of renewable energy. H2 detection has become crucial for safety in manufacturing, storage, and transportation due to its strong explosivity. To overcome the issue of explosion, there is a need for highly selective and sensitive H2 sensors that can function at low temperatures. In this research, we have adequately fabricated an unreported van der Waals (vdWs) PdSe2/WS2 heterostructure, which exhibits exceptional properties as a H2 sensor. The formation of these heterostructure devices involves the direct selenization process using chemical vapor deposition (CVD) of Pd films that have been deposited on the substrate of SiO2/Si by DC sputtering, followed by drop casting of WS2 nanoparticles prepared by a hydrothermal method onto device substrates including pre-patterned electrodes. The confirmation of the heterostructure has been done through the utilization of powder X-ray diffraction (XRD), depth-dependent X-ray photoelectron spectroscopy (XPS) and field-emission scanning electron microscopy (FE-SEM) techniques. Also, the average roughness of thin films is decided by Atomic Force Microscopy (AFM). The comprehensive research shows that the PdSe2/WS2 heterostructure-based sensor produces a response that is equivalent to 67.4% towards 50 ppm H2 at 100 °C. The response could be a result of the heterostructure effect and the superior selectivity for H2 gas in contrast to other gases, including NO2, CH4, CO and CO2, suggesting tremendous potential for H2 detection. Significantly, the sensor exhibits fast response and a recovery time of 31.5 s and 136.6 s, respectively. Moreover, the explanation of the improvement in gas sensitivity was suggested by exploiting the energy band positioning of the PdSe2/WS2 heterostructure, along with a detailed study of variations in the surface potential. This study has the potential to provide a road map for the advancement of gas sensors utilizing two-dimensional (2D) vdWs heterostructures, which exhibit superior performance at low temperatures.

Resistive switching in benzylammonium-based Ruddlesden-Popper layered hybrid perovskites for non-volatile memory and neuromorphic computing.

Artificial synapses based on resistive switching have emerged as a promising avenue for brain-inspired computing. Hybrid metal halide perovskites have provided the opportunity to simplify resistive switching device architectures due to their mixed electronic-ionic conduction, yet the instabilities under operating conditions compromise their reliability. We demonstrate reliable resistive switching and synaptic behaviour in layered benzylammonium (BzA) based halide perovskites of (BzA)2PbX4 composition (X = Br, I), showing a transformation of the resistive switching from digital to analog with the change of the halide anion. While (BzA)2PbI4 devices demonstrate gradual set and reset processes with reduced power consumption, the (BzA)2PbBr4 system features a more abrupt switching behaviour. Moreover, the iodide-based system displays excellent retention and endurance, whereas bromide-based devices achieve a superior on/off ratio. The underlying mechanism is attributed to the migration of halide ions and the formation of halide vacancy conductive filaments. As a result, the corresponding devices emulate synaptic characteristics, demonstrating the potential for neuromorphic computing. Such resistive switching and synaptic behaviour highlight (BzA)2PbX4 perovskites as promising candidates for non-volatile memory and neuromorphic computing.

Impact of alkaline earth metal doping on the structural, electronic, and optical properties of all inorganic lead-free CsSnX3(X = I, Br) perovskites: a first-principles study.

Recently, researchers have focused on developing more stable, Pb-free perovskites with improved processing efficiency and notable light harvesting ability. In this regard, Sn-based (Sn-b) perovskites have gained considerable interest in developing eco-friendly perovskite solar cells (PSCs). However, the oxidation of Sn2+to Sn4+deteriorates the performance of Sn-b PSCs. Nevertheless, this issue could be mitigated by doping alkaline earth (AE) metal. Herein, we have studied the significance of AE doping on CsSnX3(X = Br, I) perovskites using density functional theory based calculations. The structural, electronic, and optical properties of CsAEySn1-yX3(y= 0, 0.25; AE = Be, Mg, Ca, Sr) compounds were systematically investigated to explore potential candidate materials for photovoltaic applications. Formation energy calculations suggested that the synthesis of other AE-doped compounds is energetically favorable except for the Be-doped compounds. The band gaps of the materials were calculated to be in the range of 0.12-1.02 eV using the generalized gradient approximation. Furthermore, the AE doping considerably lowers the exciton binding energy while remarkably enhancing the optical absorption of CsSnX3, which is beneficial for solar cells. However, in the case of Be and Mg doping, an indirect band gap is predicted. Our theoretical findings demonstrate the potential of executing AE-doped perovskites as absorber material in PSCs, which could deliver better performance than pristine CsSnX3PSCs.

Photogating induced high sensitivity and speed from heterostructure of few-layer MoS2 and reduced graphene oxide-based photodetector.

Over the past few years, two-dimensional transition metal dichalcogenides (2D-TMDC) have attracted huge attention due to their high mobility, high absorbance, and high performance in generating excitons (electron and hole pairs). Especially, 2D molybdenum disulfide (MoS2) has been extensively used in optoelectronic and photovoltaic applications. Due to the low photo-to-dark current ratio (Iphoto/dark) and low speed, pristine MoS2-based devices are unsuitable for these applications. So, they need some improvements, i.e., by adding layers or decorating with materials of complementary majority charges. In this work, we decorated pristine MoS2 with reduced graphene oxide (rGO) and got improved dark current, Iphoto/dark, and response time. When we compared the performance of pristine MoS2 based device and rGO decorated MoS2 based device, the rGO/MoS2-based device showed an improved performance of responsivity of 3.36 A W-1, along with an Iphoto/dark of about 154. The heterojunction device exhibited a detectivity of 4.75 × 1012 Jones, along with a very low response time of 0.184 ms. The stability is also outstanding having the same device performance even after six months.

Redox Switching Behavior in Resistive Memory Device Designed Using a Solution-Processable Phenalenyl-Based Co(II) Complex: Experimental and DFT Studies.

We herein report a novel square-planar complex [CoIIL], which was synthesized using the electronically interesting phenalenyl-derived ligand LH2 = 9,9'-(ethane-1,2-diylbis(azanediyl))bis(1H-phenalen-1-one). The molecular structure of the complex is confirmed with the help of the single-crystal X-ray diffraction technique. [CoIIL] is a mononuclear complex where the Co(II) ion is present in the square-planar geometry coordinated by the chelating bis-phenalenone ligand. The solid-state packing of [CoIIL] complex in a crystal structure has been explained with the help of supramolecular studies, which revealed that the π···π stacking present in the [CoIIL] complex is analogous to the one present in tetrathiafulvalene/tetracyanoquinodimethane charge transfer salt, well-known materials for their unique charge carrier interfaces. The [CoIIL] complex was employed as the active material to fabricate a resistive switching memory device, indium tin oxide/CoIIL/Al, and characterized using the write-read-erase-read cycle. The device has interestingly shown a stable and reproducible switching between two different resistance states for more than 2000 s. Observed bistable resistive states of the device have been explained by corroborating the electrochemical characterizations and density functional theory studies, where the role of the CoII metal center and π-conjugated phenalenyl backbone in the redox-resistive switching mechanism is proposed.

Charge trapped CdS quantum dot embedded polymer matrix for a high speed and low power memristor.

The data storage requirement in the digital world is increasing day by day with the advancement of the internet of things. In this respect, nonvolatile resistive random-access memory is an option that provides high density and low power data storage capabilities. In this work, zero-dimensional colloidal CdS quantum dots and a polymer composite at an appropriate ratio were used to fabricate a memristive device. Comparison with a pristine CdS quantum dot-based device reveals that a surrounding matrix around the quantum dots is needed for observing memristive behavior. The quantum dots embedded in the polymer matrix device showed extremely stable electrical switching behavior that can be operated for more than 300 cycles and 60 000 seconds. Moreover, the device needs extremely low power to operate at a very high speed. The smooth surface morphology dictates a charge trapping mechanism for the switching phenomenon; however, an interplay between different charge transport mechanisms leads to the fast switching and high on-off ratio of the device.

Management of temporo-mandibular joint ankylosis using different surgical approaches.

Comparison of gap arthroplasty (GAP), interpositional arthroplasty (IAP) and distraction osteogenesis (DO) simultaneous with interpositional arthroplasty (DO+IAP) in management of TMJ ankylosis is of interest to dentists. The study comprised 36 individuals with TMJ ankylosis, 16 of whom were female and 20 of whom were male. Both prior to and following surgery, the maximum inter-incisal opening (MIO) and facial pattern were noted. The postoperative MIO was 33.23 ± 1.23mm, 35.24 ± 1.11mm and 38.24 ± 1.34mm in GAP, IAP and DO+IAP respectively. Data is statistically significant with high MIO observed in DO+ IAP technique and low MIO in GAP technique (p < 0.005). In addition to lengthening the mandible, concurrently processed interpositional arthroplasty alongside DO for TMJ ankylosis corrects gross asymmetry of the face, occlusal mal-alignment, midline change, and creates room for previously un-erupted teeth to emerge.

Efficacy of the Atraumatic Physics Forceps Over Conventional Extraction Forceps in Extraction of Tooth-Does it Offer an Alternative in All Types of Extraction or Only can be Used in Few Selected Types of Extraction: A Comparative Study.

We conducted this study to evaluate the efficacy of physics forceps in dental extractions as compared with conventional forceps and as well as to evaluate its atraumatic point of view. Materials and Methods: A total of 200 healthy adult patients were included in the study who reported for dental extractions, divided into two groups each containing 100 patients. The patients were randomly allocated into either group by lottery method. Results: Operating time in the physics forceps group was found to be significantly reduced as well as lesser incidence of dry socket was noted which was statistically significant on the 2nd day postoperatively. However, incidence of root fracture, buccal plate fracture, and gingival lacerations were not found to be statistically significant but their occurrence was less in the physics forceps group as compared with the conventional forceps group. Conclusion: To conclude, we can say that extractions done by physics forceps results in significant reduction in unnecessary trauma as well as stress to both the operator and patient. The forceps is an atraumatic extraction system which is a boon for the profession, thereby reducing ridge deformities and preparing the patients for future prosthesis.

Psychological distress and moral injury to oncologists and their patients during COVID-19 pandemic.

The impact of the COVID-19 pandemic on healthcare systems has been unprecedented, and the psychological effects on cancer patients and health care professionals are likely to be significant and long-lasting. The traditional methods of face-to-face health care interactions have been replaced by virtual consultations to reduce exposure to COVID-19 infection. This has put the healthcare professional under tremendous psychological pressure and led to considerable anxiety and distress among cancer patients. Treatment decisions have had to be adjusted to account for a healthcare system that has been temporarily consumed by the care of people with COVID-19, and this has put cancer patients at risk of inferior outcomes. This has had the potential to cause moral injury and psychological distress to health care professionals as well as patients, who have had to deal with a range of stressors due to the uncertainty, sense of loss of control, reduced accessibility to medications and social support, changes to personal circumstances (e.g. financial pressures) and fear of death due to COVID-19 infection. Long term consequences also include post-traumatic responses and complex grief reactions. Cancer services in particular should gear themselves to recognize and monitor these effects and allocate adequate resources to combat them in the months and years to come.

Clinico-Epidemiological Profile of Allergic Contact Dermatitis and Its Correlation With Patch Testing in a Tertiary Care Center in Eastern India.

BACKGROUND: Allergic contact dermatitis (ACD) is one of the most common skin disorders seen among patients attending dermatology clinics in India. Patch testing is the gold standard for diagnosing ACD. The clinical-epidemiological pattern of ACD and the allergen-causing it may be different in different geographic locations. Finding the profile of allergens commonly causing ACD in a particular region will help to formulate prevention strategies for the development of ACD. AIM AND OBJECTIVE: The primary aim of the study was to find out the clinical-epidemiological distribution of allergic contact dermatitis and to identify the common allergens causing it by patch testing in this region of India. MATERIALS AND METHODS: A total of 111 cases of ACD were included in the study. Clinico epidemiological profiles of all patients were documented. The patch testing was performed in the outpatient department using the antigens of the Indian Standard Series kit (Systopic Laboratories Pvt. Ltd., New Delhi, India). Patches were removed after 48 hours (two days) of application. The first reading was taken 15 to 20 minutes after the removal of patches on day two. A second reading was taken on day four (96 hours of application) to confirm the presence of an allergic reaction.  Results: The patch test was found to be positive in 69% of cases. It was observed that male persons from lower socioeconomic status were getting ACD on most accounts. Potassium dichromate (PDC) was found to be the most common allergen (30.43%) followed by parthenium (26.08%), para-phenylenediamine (PPD) (21.73%), nickel sulfate (18.84%), chlorocresol (15.94%), black rubber (14.49%), cobalt sulfate (13.04%), and wool alcohols (7.24%) respectively. CONCLUSION: Our study showed potassium dichromate is the commonest allergen causing ACD in this part of the country. The importance of patch testing lies mainly in educating the patient regarding the avoidance of exposure to particular allergens to avoid the development of new ACD as well as an exaggeration of pre-existing ACD.

Basidiobolomycosis: Case Report and Literature Overview.

Basidiobolomycosis or subcutaneous zygomycosis or subcutaneous phycomycosis is a chronic granulomatous infection of skin and subcutaneous tissue, caused by a saprophytic filamentous fungus, Basidiobolus ranarum, clinically characterized by firm, painless subcutaneous swelling with smooth and rounded edges. Histopathological features include the peculiar Splendore-Hoeppli phenomenon. Culture on Sabouraud dextrose agar shows creamy white, heaped up, and furrowed colonies. This entity has been reported from tropical and subtropical regions of the world and the southern part of India. We report a case of Basidiobolomycosis in a seven-year-old girl from Eastern India, which was excised twice before presenting to us. We diagnosed the case as Basidiobolomycosis based on clinical features, histopathology, and culture findings, and treated it with itraconazole.

Hot Injection-Based Synthesized Colloidal CdSe Quantum Dots Embedded in Poly(4-vinylpyridine) (PVP) Matrix Form a Nanoscale Heterostructure for a High On-Off Ratio Memory-Switching Device.

Chalcogenide-based quantum dots are useful for the application of memory-switching devices because of the control in the trap states in the materials. The control in the trap states can be achieved using a hot-injection colloidal synthesis method that produces temperature-dependent size-variable quantum dots. In addition to this, formation of a nanoscale heterostructure with an insulating material adds to the charge-trapped switching mechanism. Here, we have shown that the colloidal monodispersed CdSe quantum dots and poly(4-vinylpyridine) (PVP) formed a nanoscale heterostructure between themselves when taken in a suitable ratio to fabricate a device. This heterostructure helps realize memory-switching in the device with a maximum on-off current ratio of 105. The switching in the device is mainly due to the trap states in the CdSe quantum dots. The conduction in the off state is due to thermal charge injection and space charge injection conduction and in the on state, due to the Ohmic conduction mechanism.

Decision making, management, and midterm outcomes of postinfarction ventricular septal rupture: Our experience with 21 patients.

Context: Ventricular septal rupture (VSR) is a dreaded complication following myocardial infarction. Surgical repair of VSR is associated with significant early mortality. Variable outcomes in terms of early mortality and midterm functional status have been reported from different centers. Aims: In our study, we attempt to review the experience of decision making and surgical repair of postinfarction VSR, and to analyze the factors contributing to the early mortality and midterm outcome after repair. Materials and Methods: It is a retrospective study. Data were summarized retrospectively by frequencies and percentages for categorical factors, and means and standard deviations for continuous factors. Multivariate logistic regression, odds ratios, 95% confidence intervals, and P value were calculated for different variables to determine their independent effect on operative mortality. All surviving patients answered the EQ-5D Health Questionnaire. Results: Preoperative renal failure, left ventricular dysfunction (moderate and severe), and Killip class (III and IV) were significantly associated with early mortality after surgery. Small residual ventricular septal defect (VSD) was not found to affect the midterm quality of life. Conclusions: Early surgical repair benefits the patient by preventing early end-organ damage. The renal failure left ventricular dysfunction (moderate and severe) and Killip class (III and IV) adversely affect early outcomes after surgery. Small residual ventricular septal defect (VSD) does not affect the midterm quality of life.

Strain induced valley degeneracy: a route to the enhancement of thermoelectric properties of monolayer WS2.

Two-dimensional transition metal dichalcogenides show great potential as promising thermoelectric materials due to their lower dimensionality, the unique density of states and quantum confinement of carriers. Here the effects of mechanical strain on the thermoelectric performances of monolayer WS2 have been investigated using density functional theory associated with semiclassical Boltzmann transport theory. The variation of the Seebeck coefficient and band gap with applied strain has followed the same type of trend. For n-type material the relaxation time scaled power factor (S 2 σ/τ) increases by the application of compressive strain whereas for p-type material it increases with the application of tensile strain due to valley degeneracy. A 77% increase in the power factor has been observed for the n-type material by the application of uniaxial compressive strain. A decrease in lattice thermal conductivity with the increase in temperature causes an almost 40% increase in ZT product under applied uniaxial compressive strain. From the study, it is observed that uniaxial compressive strain is more effective among all types of strain to enhance the thermoelectric performance of monolayer WS2. Such strain induced enhancement of thermoelectric properties in monolayer WS2 could open a new window for the fabrication of high-quality thermoelectric devices.

Isolated persistent left superior vena cava: A case report and its clinical implications.

The venous anomaly of a persistent left superior vena cava (PLSVC) affects 0.3%-0.5% of the general population. PLSVC with absent right superior vena cava, also termed as "isolated PLSVC," is an extremely rare venous anomaly. Almost half of the patients with isolated PLSVC have cardiac anomalies in the form of atrial septal defect, endocardial cushion defects, or tetralogy of Fallot. Isolated PLSVC is usually innocuous. Its discovery, however, has important clinical implications. It can pose clinical difficulties with central venous access, cardiothoracic surgeries, and pacemaker implantation. When it drains to the left atrium, it may create a right to left shunt. In this case report, we present the incidental finding of isolated PLSVC in a patient who underwent aortic valve replacement. Awareness about this condition and its variations is important to avoid complications.

Inventing a co-axial atomic resolution patch clamp to study a single resonating protein complex and ultra-low power communication deep inside a living neuron cell.

To read the signals of single molecules in vitro on a surface, or inside a living cell or organ, we introduce a coaxial atom tip (coat) and a coaxial atomic patch clamp (COAPAP). The metal-insulator-metal cavity of these probes extends to the atomic scale (0.1[Formula: see text]nm), it eliminates the cellular or environmental noise with a S/N ratio 105. Five ac signals are simultaneously applied during a measurement by COAT and COAPAP to shield a true signal under environmental noise in five unique ways. The electromagnetic drive in the triaxial atomic tips is specifically designed to sense anharmonic vibrational and transmission signals for any system between 0.1[Formula: see text]nm and 50[Formula: see text]nm where the smallest nanopatch clamp cannot reach. COAT and COAPAP reliably pick up the atomic scale vibrations under the extreme noise of a living cell. Each protein's distinct electromagnetic, mechanical, electrical and ionic vibrational signature studied in vitro in a protected environment is found to match with the ones studied inside a live neuron. Thus, we could confirm that by using our probe blindly we could hold on to a single molecule or its complex in the invisible domain of a living cell. Our decade long investigations on perfecting the tools to measure bio-resonance of all forms and simultaneously in all frequency domains are summarized. It shows that the ratio of emission to absorption resonance frequencies of a biomaterial is around [Formula: see text], only a few in the entire em spectrum are active that regulates all other resonances, like mechanical, ionic, etc.

Inventing atomic resolution scanning dielectric microscopy to see a single protein complex operation live at resonance in a neuron without touching or adulterating the cell.

A substantial ion flow in a normally wet protein masks any other forms of signal transmission. We use hysteresis and linear conduction (both are artifacts) as a marker to precisely wet a protein, which restricts the ionic conduction (hysteresis disappears), and at the same time, it is not denatured (quantized conductance and Raman spectra are intact). Pure electric visualization of proteins at work by eliminating the screening of ions, electrons, would change the way we study biology. Here we discuss the technical challenges resolved for imaging a protein or live cell using nonlinear dielectric response (spatial distribution of conductance, capacitance and phase, GCP trio). We electromagnetically triggered electrical, mechanical, thermal and ionic resonant vibrations in a protein. During resonant oscillations, we imaged the protein using resonant scanning tunneling microscopy of biomaterials (Brestum) and during ionic firing we imaged live what happens inside an axon core of a neuron by using our atomic scale scanning dielectric microscopy (Asadim). Both Asadim and Brestum are housed in a homebuilt scanning tunneling microscope (bio-STM) and a special micro-grid developed by us (patent JP-5187804) for fractal supercomputing. We found the trick to turn a membrane transparent and see inside without making any physical contact. We image live that a protein molecule adopts a unique configuration for each resonance frequency, - thus far unknown to biology. "Membrane alone fires" is found to be wrong after a century, micro-neuro-filaments communicate prior to firing to decide its necessity and then regulate it suitably. We introduce a series of technologies e.g., fractal grid, point contact, micro THz antenna, to discover that from atomic structure to a living cell, the biomaterials vibrate collectively.

Live visualizations of single isolated tubulin protein self-assembly via tunneling current: effect of electromagnetic pumping during spontaneous growth of microtubule.

As we bring tubulin protein molecules one by one into the vicinity, they self-assemble and entire event we capture live via quantum tunneling. We observe how these molecules form a linear chain and then chains self-assemble into 2D sheet, an essential for microtubule, --fundamental nano-tube in a cellular life form. Even without using GTP, or any chemical reaction, but applying particular ac signal using specially designed antenna around atomic sharp tip we could carry out the self-assembly, however, if there is no electromagnetic pumping, no self-assembly is observed. In order to verify this atomic scale observation, we have built an artificial cell-like environment with nano-scale engineering and repeated spontaneous growth of tubulin protein to its complex with and without electromagnetic signal. We used 64 combinations of plant, animal and fungi tubulins and several doping molecules used as drug, and repeatedly observed that the long reported common frequency region where protein folds mechanically and its structures vibrate electromagnetically. Under pumping, the growth process exhibits a unique organized behavior unprecedented otherwise. Thus, "common frequency point" is proposed as a tool to regulate protein complex related diseases in the future.