Impact of Atomic Defects on Water Contact Angle of 2D Molybdenum Disulfide Surfaces.

Interfacial dynamics within nanofluidic systems are crucial for applications like water desalination and osmotic energy harvesting. Understanding these dynamics can inform the rational optimization of two-dimensional (2D) materials and devices for such applications. This study explores the wetting behavior of realistic 2D MoS2 surfaces incorporating vacancies and atomic steps, known as atomic defects. We employ a combined density functional theory (DFT) and molecular dynamics (MD) computational approach to elucidate the influence of atomic defects on the MoS2-water interface. DFT calculations are utilized to determine the charge distribution within MoS2. Subsequently, free energy calculations are obtained through MD simulations of the MoS2-water interface. Our findings underscore the importance of incorporating atomic defects into MoS2 surfaces for accurate water contact angle (WCA) predictions in nanofluidic simulations, particularly when using Abal et al. force field parameters. However, the force field developed by Liu et al. yielded more accurate results for pristine MoS2 surfaces. While these parameters provide reliable outcomes for pristine MoS2 surfaces, their application to surfaces with defects may lead to underestimation of WCA. This highlights the critical need for realistic surface representations in nanofluidic modeling to accurately capture the complex interactions between water and MoS2 materials.

A buffering PVDF-HFP-based gel polymer electrolyte for stable and flexible lithium batteries.

Flexible lithium batteries (FLBs) are highly regarded as potential candidates for next-generation batteries due to their versatility in various applications. However, the main focus in the development of FLBs lies in addressing mechanical challenges such as crack propagation under conditions of flexibility and stretchability. Herein, this work presents a novel design of a gel polymer electrolyte (GPE112) film prepared by solution-casting methods. The GPE112 film shows high ion conductivity of 2.12 × 10-4 S cm-1, a window voltage stability of ∼4.6 V, and compatibility with various commercial cathodes such as LiFePO4, LiCoO2 and LiNi0.8Co0.1Mn0.1O2. On the other hand, the mechanically robust GPE112 film exhibits elongation at break of ∼41%, making it a potentially superior alternative to a commercial polypropylene (PP) separator. Furthermore, through finite element method (FEM) simulation, the utilization of a hot-pressed polymer electrolyte in conjunction with a cathode active layer demonstrates the potential to mitigate crack propagation and prevent delamination, leading to the development of flexible batteries with robust structures. Generally, the investigation demonstrates that the prepared GPE112 film provides potential application in safe FLBs no matter the electrochemical or mechanical properties.

Assessment of obstructive airway disease in the multicenter SWORD survey India.

BACKGROUND AND OBJECTIVES: The study aimed to assess the control of asthma and the severity of chronic obstructive pulmonary disease (COPD) and evaluate the adequacy of treatment in patients presenting to the outpatient department (OPD) across India. The secondary aim was to assess the risk factors associated with poorly controlled asthma and severe COPD. MATERIALS AND METHODS: This is the analysis of Phase IV of the multicenter questionnaire-based point prevalence SWORD survey, conducted in May 2018, and designed to capture details on disease control and treatment as per the global initiative for asthma and the global initiative for chronic obstructive lung disease guidelines. RESULTS: Of the 5,311 respiratory disease patients presenting to the OPD, there were 1,419 and 412 patients with asthma and COPD, respectively, across 290 sites in India. There were 1,022 (72%) patients having well-controlled asthma, 293 (20.6%) patients with partly controlled asthma, and 104 (7.4%) patients with poorly controlled asthma. Of the 412 patients with COPD, there were 307 (74.5%) in A, 54 (13.1%) in B, and 51 (12.4%) in the E category. In spite of poor control or severe disease, 34.8% of asthmatic and 25.7% of patients in the B and E categories of COPD were not using any medicine. Risk factors for partly and poorly controlled asthma included rain wetting (adjusted odds ratio [AOR]: 1.59, 95% confidence interval [CI]: 1.02-2.47) and gastroesophageal reflux disease (AOR: 1.50, 95%CI: 1.08-2.10). CONCLUSION: This study identifies a gap in the treatment of both poorly controlled asthma and severe COPD. A substantial number of patients had poorly controlled asthma and severe COPD, and many were either not taking treatment or taking it inappropriately.

Modulating the Water Contact Angle Using Surface Roughness: Interfacial Properties of Hexagonal Boron Nitride Surfaces.

Hexagonal boron nitride (hBN) exhibits immense potential in H2O-related technologies, but its interaction with H2O, especially on rough surfaces, remains unclear. This study unravels the influence of surface roughness and force field selection on hBN wettability using molecular dynamics (MD) simulations. We leverage quantum mechanical calculations to accurately capture the hBN surface charge distribution and combine it with free energy calculations via MD simulations for the hBN-H2O interfaces. Incorporating surface roughness into the model yields results in close agreement with the experimental contact angle of 66° for H2O using FF-3 force fields, validating the simulation approach. However, this approach can yield an unrealistic water contact angle (WCA) of 0° for FF-2 force fields, highlighting the crucial role of force field selection and realistic surface representations. We further dissect the impact of roughness on the WCA, identifying the individual contributions of electrostatic and Lennard-Jones interactions to the work of adhesion. This research investigates the combined impact of surface roughness and force fields on interfacial properties, providing new possibilities for the advancement and optimization of desalination.

Electrospun Polymeric Nanofibers: Current Trends in Synthesis, Surface Modification, and Biomedical Applications.

Electrospun polymeric nanofibers are essential in various fields for various applications because of their unique properties. Their features are similar to extracellular matrices, which suggests them for applications in healthcare fields, such as antimicrobials, tissue engineering, drug delivery, wound healing, bone regeneration, and biosensors. This review focuses on the synthesis of electrospun polymeric nanofibers, their surface modification, and their biomedical applications. Nanofibers can be fabricated from both natural and synthetic polymers and their composites. Even though they mimic extracellular matrices, their surface features (physicochemical characteristics) are not always capable of fulfilling the purpose of the target application. Therefore, they need to be improved via surface modification techniques. Both needle-based and needleless electrospinning are thoroughly discussed. Various techniques and setups employed in each method are also reviewed. Furthermore, pre- and postspinning modification approaches for electrospun nanofibers, including instrument design and the modification features for targeted biomedical applications, are also extensively discussed. In this way, the remarkable potential of electrospun polymeric nanofibers can be highlighted to reveal future research directions in this dynamic field.

Sodium Niobate Nanowires Embedded PVA-Hydrogel-Based Triboelectric Nanogenerator for Versatile Energy Harvesting and Self-Powered CO Gas Sensor.

The surging demand for sustainable energy solutions and adaptable electronic devices has led to the exploration of alternative and advanced power sources. Triboelectric Nanogenerators (TENGs) stand out as a promising technology for efficient energy harvesting, but research on fully flexible and environmental friendly TENGs still remain limited. In this study, an innovative approach is introduced utilizing an ionic-solution modified conductive hydrogel embedded with piezoelectric sodium niobate nanowires-based Triboelectric Nanogenerator (NW-TENG), offering intrinsic advantages to healthcare and wearable devices. The synthesized NW-TENG, with a 12.5 cm2 surface area, achieves peak output performance, producing ≈840 V of voltage and 2.3 µC of charge transfer, respectively. The rectified energy powers up 30 LEDs and a stopwatch; while the NW-TENG efficiently charges capacitors from 1µF to 100 µF, reaching 1 V within 4 to 65 s at 6 Hz. Integration with prototype carbon monoxide (CO) gas sensor transform the device into a self-powered gas sensory technology. This study provides a comprehensive understanding of nanowire effects on TENG performance, offering insights for designing highly flexible and environmentally friendly TENGs, and extending applications to portable self-powered gas sensors and wearable devices.

Experimental and Theoretical Insights into Interfacial Properties of 2D Materials for Selective Water Transport Membranes: A Critical Review.

Interfacial properties, such as wettability and friction, play critical roles in nanofluidics and desalination. Understanding the interfacial properties of two-dimensional (2D) materials is crucial in these applications due to the close interaction between liquids and the solid surface. The most important interfacial properties of a solid surface include the water contact angle, which quantifies the extent of interactions between the surface and water, and the water slip length, which determines how much faster water can flow on the surface beyond the predictions of continuum fluid mechanics. This Review seeks to elucidate the mechanism that governs the interfacial properties of diverse 2D materials, including transition metal dichalcogenides (e.g., MoS2), graphene, and hexagonal boron nitride (hBN). Our work consolidates existing experimental and computational insights into 2D material synthesis and modeling and explores their interfacial properties for desalination. We investigated the capabilities of density functional theory and molecular dynamics simulations in analyzing the interfacial properties of 2D materials. Specifically, we highlight how MD simulations have revolutionized our understanding of these properties, paving the way for their effective application in desalination. This Review of the synthesis and interfacial properties of 2D materials unlocks opportunities for further advancement and optimization in desalination.

Room-temperature response of MOF-derived Pd@PdO core shell/γ-Fe2O3 microcubes decorated graphitic carbon based ultrasensitive and highly selective H2 gas sensor.

With the current upsurge in hydrogen economies all over the world, an increased demand for improved chemiresistive H2 sensors that are highly responsive and fast acting when exposed to gases is expected. Owing to safety concerns about explosive and highly flammable H2 gas, it is important to develop resistive sensors that can detect the leakage of H2 gas swiftly and selectively. Currently, interest in metal-organic frameworks (MOFs) for gas-sensor applications is increasing due to their open-metal sites, large surface area, and unique surface morphologies. In this research, a highly selective and sensitive H2-sensor was established based on graphitic carbon (GC) anchored spherical Pd@PdO core-shells over γ-Fe2O3 microcube (Pd@PdO/γ-Fe2O3@GC which is termed as S3) heterostructure materials. The combined solvothermal followed by controlled calcination-assisted S3 exhibited a specific morphology with the highest surface area of 79.12 m2 g-1, resulting in fast response and recovery times (21 and 29 s, respectively), and excellent sensing performance (ΔR/R0∼ 96.2 ± 1.5), outstanding long-term stability, and a 100 ppb detection limit when detecting H2-gas at room temperature (mainly in very humid surroundings). This result proves that adsorption sites provided by S3 can promote surface reactions (adsorption and desorption) for ultrasensitive and selective H2gas sensors.

Pulmonary Manifestations in Patients of Rheumatoid Arthritis and its Correlation with Severity of Disease.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic inflammatory disease of unknown etiology marked by symmetric, peripheral polyarthritis. RA has a prevalence of 1-2% in the general adult population. The mortality rate in patients with RA increases during the course of the disease, with a tendency to accelerate after 15 yearsAim: To study the pulmonary manifestations and their severity using [Disease Activity Score (DAS)-28 score] in patients of RAMaterials and methods: Present study was conducted in the Department of Medicine, Sardar Patel Medical College and Associated Group of Hospitals Bikaner, Bikaner, Rajasthan, India, on 100 patients. This study was a cross-sectional, observational study conducted over 1 year. Consecutive cases of RA patients attending the outpatient department or admitted to the medicine wards were selected according to the inclusion and exclusion criteriaResults: Pulmonary manifestation was present in a total of 38% of cases, while the remaining 62% of cases had no pulmonary manifestation. The presence of comorbidity and C-reactive protein (CRP) was significantly associated with pulmonary manifestation in RA patients. On high-resolution computed tomography (HRCT), the most common finding was interstitial lung disease (ILD) (60.5%), with usual interstitial pneumonia (UIP) as the most common pattern. On performing a pulmonary function test (PFT), 33 patients (86.84%) had an abnormal result, with restrictive as the most common patternConclusion: The patients of RA, especially those with advanced age, long duration of disease, male sex, and associated comorbidity, should be screened for pulmonary complications of RA using X-ray chest and PFT, supplemented by HRCT chest wherever required.

Triazole based Schiff bases and their oxovanadium(IV) complexes: Synthesis, characterization, antibacterial assay, and computational assessments.

The synthesis and characterization of two new Schiff base ligands containing 1,2,4-triazole moieties and their oxovanadium(IV) complexes have been reported. The ligands and their complexes were studied by ultraviolet-visible (UV-Vis), Fourier transform infrared (FTIR), proton nuclear magnetic resonance (1H NMR), electron paramagnetic resonance (EPR), X-ray diffraction (XRD), conductivity measurement, cyclic voltammetry (CV), and elemental analyses. The molar conductance of oxovanadium(IV) complexes were found to be relatively low, depicting their non-electrolytic nature. The XRD patterns reveal the size of particles to be 47.53 nm and 26.28 nm for the two complexes in the monoclinic crystal system. The molecular structures, geometrical parameters, chemical reactivity, stability, and frontier molecular orbital pictures were determined by density functional theory (DFT) calculations. The theoretical vibrational frequencies and EPR g-factors (1.98) were found to correlate well with the experimental values. A distorted square pyramidal geometry with C2 symmetry of the complexes has been proposed from experimental and theoretical results in a synergistic manner. The antimicrobial sensitivity of the ligands and their metal complexes assayed in vitro against four bacterial pathogens viz. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella Typhi showed that the oxovanadium(IV) complexes are slightly stronger antibacterial agents than their corresponding Schiff base precursors. The binding affinities obtained from the molecular docking calculations with the receptor proteins of bacterial strains (2EUG, 3UWZ, 4GVF, and 4JVD) showed that the Schiff bases and their oxovanadium(IV) complexes have considerable capacity inferring activeness for effective inhibition. The molecular dynamics simulation of a protein-ligand (4JVD-HL2) complex with the best binding affinity of -12.8 kcal/mol for 100 ns showed acceptable stability of the docked pose and binding free energy of -15.17 ± 2.29 kcal/mol from molecular mechanics-generalized Born surface area (MM-GBSA) calculations indicated spontaneity of the reaction. The outcome of the research shows the complementary role of computational methods in material characterization and provides an interesting avenue to pursue for exploring new triazole based Schiff's bases and its vanadium compounds for better properties.

COVID Associated Invasive Aspergillosis.

To study the possible association between invasive fungal sinusitis (aspergillosis) and coronavirus disease. An observational study was conducted at a tertiary care centre over 6 months, involving all patients with aspergillosis of the paranasal sinuses suffering from or having a history of COVID-19 infection. 92 patients presented with aspergillosis, all had an association with COVID-19 disease. Maxillary sinus (100%) was the most common sinus affected. Intraorbital extension was seen in 34 cases, while intracranial extension was seen in 5 cases. Diabetes mellitus was present in 75 of 92 cases. All had a history of steroid use during their coronavirus treatment. New manifestations of COVID-19 are appearing over time. The association between coronavirus and aspergillosis of the paranasal sinuses must be given serious consideration. Uncontrolled diabetes and overzealous use of steroids are two main factors aggravating the illness, and both of these must be properly checked.

Post Covid-19 Sinonasal Candidiasis: A Crisis Within the Pandemic.

The aim of this study was to find out the association of sinonasal candidiasis and Covid-19 infection. A prospective observational study was conducted at a tertiary care centre from April to September 2021, involving all patients with invasive candidiasis of the paranasal sinuses having a history of Covid-19 infection. A total of 18 patients of covid associated sinonasal candidiasis among the 475 cases of fungal rhinosinusitis were studied. All patients had involvement of nose and sinuses and 2 patients had orbital involvement with no loss of vision, while 3 had intracranial extensions and 1 had pulmonary involvement. Mandible was involved in 1 patient alone, while the maxilla and palate were involved in 5 patients. 15 patients were hypertensive, 12 diabetics and 1 had aplastic anaemia. Cultures showed that 8 patients had C. parapsilosis, 5 had C. albicans, 3 had C. tropicalis and 2 had mixed fungal infections. All patients underwent surgical debridement and antifungal administration. They were followed up for a minimum of 3 months. There was only one mortality (with aplastic anaemia), rest 17 were disease free at the time of writing this article. This is perhaps the first case series of post covid sinonasal candidiasis in the world. Invasive sinonasal candidiasis is a newer sequela of COVID-19 infection. Uncontrolled diabetes and over-zealous use of steroids at the time of Covid-19 are few of the known risk factors. Early surgical intervention and anti-fungal treatment should be sought for management.

Design of a COVID-19 treatment facility in a sustainable health-care environment.

Due to the recent pandemic situation that has erupted all around us, healthcare facility design is a must. Healthcare providers and administrators must concentrate on the changes that must be made in existing healthcare facilities. The isolated healthcare facilities are essential because the corona virus is spread mainly through close contact (within six feet), such as handshaking (if someone's hands are infected) or touching contaminated surfaces. Healthcare facilities are most susceptible to the spread of the corona virus due to the high number of symptomatic patients admitted. Coronavirus is the leading cause of infectious disease morbidity and mortality worldwide. Thus, if the pandemic situation worsens, new plans and designs for existing healthcare facilities will be required, as well as temporary versions. Societal gains from increased research in this area. In the coming years, healthcare workers will be better trained, and healthcare facilities will be upgraded. This paper proposes new plans and designs to address the issues raised.

A Study of Pulmonary Function Tests in Patients with Chronic Rhinosinusitis Following Endoscopic Sinus Surgery.

Chronic inflammatory disorders of the upper airways are extremely prevalent and they have a major impact on public health.To assess the change in pulmonary function tests in patients of chronic rhinosinusitis undergoing functional endoscopic sinus surgery pre operatively and post operatively.To evaluate the difference in mean of FEV1, FEV1%, FVC, FVC%, FEV1/FVC in patients of chronic rhinosinusitis undergoing functional endoscopic sinus surgery.Prospective observational study.From July 2019 to September 2020 in Department of ENT and Head & Neck surgery, SMS Medical College, Jaipur.There was a significant improvement in the mean FEV1, FEV1%, FVC, and FVC% values post-surgically (p < 0.05). In our study, there was also a significant improvement in the FEV1/FVC value at one month postoperatively, reflecting the effect of FESS on relieving the symptomatic lower airway obstruction.Our study concludes that following Functional Endoscopic Sinus Surgery there is significant improvement in pulmonary function tests reflecting the improvement of asymptomatic lower airway disease in cases of chronic rhinosinusitis.

Metal Organic Framework-Derived ZnO@GC Nanoarchitecture as an Effective Hydrogen Gas Sensor with Improved Selectivity and Gas Response.

Although they are not as favorable as other influential gas sensors, metal-oxide semiconductor-based chemiresistors ensure minimal surface reactivity, restricting their gas selectivity, gas response, and reaction kinetics, particularly when functioning at room temperature (RT). A hybrid design, which includes metal-oxide/carbon nanostructures and passivation with specific gas filtration layers, can address the concerns of surface reactivity. We present a novel hierarchical nanostructured zinc oxide (ZnO), decorated with graphitic carbon (GC) and synthesized via a wet-chemical strategy, which is then followed by the self-assembly of a zeolitic imidazolate framework (ZIF-8). Because of its large surface area, high porosity, and efficient inspection of other analyte (interfering) gases, the ZnO@GC can provide intensified surface reactivity at RT. In the present study, such a hybrid sensor confirmed extraordinary gas sensing properties, which was characterized by excellent H2 selectivity, fast response, rapid recovery kinetics, and high gas response (ΔR/R0 ∼ 124.6%@10 ppm), particularly in extremely humid environments. The results reveal that adsorption sites provided by the ZIF-8 template-based ZnO@GC frameworks facilitate the adsorption and desorption of H2.

Proportionate clinical burden of respiratory diseases in Indian outdoor services and its relationship with seasonal transitions and risk factors: The results of SWORD survey.

BACKGROUND: The Global Burden of Disease data suggest that respiratory diseases contribute to high morbidity in India. However, the factors responsible for high morbidity are not quite clear. Therefore, the Seasonal Waves Of Respiratory Disorders (SWORD) study was planned to estimate the point prevalence due to respiratory diseases in Indian OPD services and its association with risk factors and change in seasons. METHODS: In this point prevalence observational multicenter study conducted during 2017-18, participating physicians recorded information of consecutive patients in response to a questionnaire. The study was conducted on four predetermined days representing transition of Indian seasons i.e., February (winter), May (summer), August (monsoon), and November (autumn). RESULTS: The eligible number of patients from across 302 sites in India was 25,177. The mean age of study population was 46.1±18.1 years, 14102(56.0%) were males and 11075(44.0%) females. The common diagnoses were: asthma(29.8%), chronic obstructive pulmonary disease (COPD),15.6%, respiratory tract infections (RTIs),11.3%, and tuberculosis(8.7%). All these conditions showed significant seasonal trends (Asthma 31.4% autumn vs. 26.5% summer, COPD 21.1% winter vs. 8.1% summer, RTIs 13.3% winter vs. 4.3% summer, and tuberculosis 12.5% autumn vs. 4.1% summer, p<0.001 for each respectively). After adjustment for risk factors, asthma was significantly associated with exposure to molds (OR:1.12,CI:1.03-1.22), pet animals (OR:1.07,CI:1.01-1.14), recent-travel (OR:1.22,CI:1.13-1.32), and rain-wetting (OR:1.27,CI:1.15-1.40); and RTIs with rain-wetting (OR:1.53,CI:1.34-1.74), and recent-travel (OR:1.17,CI:1.05-1.30). CONCLUSIONS: The SWORD study showed wide seasonal variations in outpatient attendance of patients with common respiratory conditions. Novel risk-factors associated with respiratory diseases were also identified.

Electrospun carbon nanofibre-assisted patterning of metal oxide nanostructures.

This work establishes carbon nanofibre-mediated patterning of metal oxide nanostructures, through the combination of electrospinning and vapor-phase transport growth. Electrospinning of a suitable precursor with subsequent carbonization results in the patterning of catalyst gold nanoparticles embedded within carbon nanofibres. During vapor-phase transport growth, these nanofibres allow preferential growth of one-dimensional metal oxide nanostructures, which grow radially outward from the nanofibril axis, yielding a hairy caterpillar-like morphology. The synthesis of metal oxide caterpillars is demonstrated using zinc oxide, indium oxide, and tin oxide. Source and substrate temperatures play the most crucial role in determining the morphology of the metal oxide caterpillars, whereas the distribution of the nanofibres also has a significant impact on the overall morphology. Introducing the current methodology with near-field electrospinning further facilitates user-defined custom patterning of metal oxide caterpillar-like structures.

Obesity, Thyroid and OSA: An Intriguing Triangle.

The complex relationship between BMI, thyroid and its effects on OSA raises a question on how patients with suspected OSA should be evaluated. Some studies have described an association between thyroid disorders and OSA. Whether this is a direct effect of thyroid disorders, or it is indirectly related to BMI values is an important point to ponder. The aim of this study was to estimate the prevalence of thyroid disorders in relation to BMI in newly diagnosed patients with OSA (AHI > 5/h on diagnostic Polysomnography) at sleep lab of our tertiary care centre. In addition, we compared baseline characteristics of OSA patients with thyroid parameters. MATERIAL: In this hospital based observational study, recently diagnosed OSA on the basis of PSG showing AHI > 5/ h according to the AASM 2012 scoring rules and age more than 18 years were recruited from OPD and in-patients of SMS Medical College Jaipur. Patients on previous CPAP treatment, mixed or predominantly central sleep apnea, known diabetics and language barriers or cognitive or psychiatric disorders that made informed consent difficult to obtain were excluded. OBSERVATION: During the study period, 65 patients with treatment naïve OSA and a mean age of 52.28±10.92 year, a mean body mass index (BMI) of 34.73±7.20 kg/m2 underwent thyroid function tests. In the OSA patients, the prevalence of newly diagnosed clinical hypothyroidism was 12.3%. In Mild OSA the mean FT3 (ng/ml), FT4 (ng/dl), TSH (mIU/l) and mean AHI score was 3.10±0.71, 1.37±0.58, 3.64±1.37 and 7.74±3.55 respectively. Similarly, mean FT3 (ng/ml), FT4 (ng/dl), TSH (mIU/l) and mean AHI score were 2.97±0.93, 1.46±0.79, 6.33±8.05 and 17.42±88.90 respectively in moderate OSA and 3.32±0.58, 1.23±0.46, 3.55±1.82 and 45.54±21.38 respectively in severe OSA. There was a statistically significant difference between mild moderate and severe OSA regarding thyroid profile as well as BMI with p of <0.05. CONCLUSION: The prevalence of hypothyroidism was common among patients with OSA and the severity of OSA correlated with thyroid function tests and BMI.

In Situ Exsolution Catalyst: An Innovative Approach to Develop Highly Selective and Sensitive Gas Sensors.

The gas sensing characteristics of oxide semiconductors can be enhanced by loading noble metal or metal oxide catalysts. The uniform distribution of nanoscale catalysts with high thermal stability over the sensing materials is essential for sensors operating at elevated temperatures. An in situ exsolution process, which can be applied to catalysts, batteries, and sensors, provides a facile synthetic route for developing second-phase nanoparticles with uniform distribution, excellent thermochemical stability, and strong adhesion to the mother phase. In this study, we investigated the effect of Co-exsolved nanoparticles on the gas sensing characteristics of La0.43Ca0.37Co0.06Ti0.94O3-d (LCCoT). The amount and size of the Co-exsolved nanoparticles on the surface of the perovskite mother phase were adjusted depending on the reduction temperature of the exsolution process. The LCCoT with Co-exsolved nanoparticles prepared by reduction at 700 °C exhibited a response (resistance ratio) of 116.3 to 5 ppm ethanol at 350 °C, which was 10-fold higher than the response of a sensor without exsolution. The high gas response was attributed to the catalytic effect promoted by the uniformly distributed Co-exsolved nanoparticles and the formation of p-n junctions on the sensing surface during reduction. Additionally, we demonstrated the catalytic effect of Co-exsolved nanoparticles using a proton transfer reaction-quadrupole mass spectrometer. By controlling the amount and distribution of exsolved nanoparticles on semiconductor chemiresistors, a new pathway for designing high-performance gas sensors with enhanced thermal stability can be achieved.

How Grain Boundaries and Interfacial Electrostatic Interactions Modulate Water Desalination via Nanoporous Hexagonal Boron Nitride.

To fulfill the increasing demand for drinking water, researchers are currently exploring nanoporous two-dimensional materials, such as hexagonal boron nitride (hBN), as potential desalination membranes. A prominent, yet unsolved challenge is to understand how such membranes will perform in the presence of defects or surface charge in the membrane material. In this work, we study the effect of grain boundaries (GBs) and interfacial electrostatic interactions on the desalination performance of bicrystalline nanoporous hBN using classical molecular dynamics simulations supported by quantum-mechanical density functional theory (DFT) calculations. We investigate three different nanoporous bicrystalline hBN configurations, with symmetric tilt GBs having misorientation angles of 13.2, 21.8, and 32.2°. Using lattice dynamics calculations, we find that grain boundaries alter the areas and shapes of nanopores in bicrystalline hBN, as compared to the nanopores in monocrystalline hBN. We observe that, although bicrystalline nanoporous hBN with a misorientation angle of 13.2° shows an improved water flow rate by ∼30%, it demonstrates reduced Na+ ion rejection by ∼6%, as compared to monocrystalline hBN. We also uncover the role of the nanopore shape in water desalination, finding that more elongated pores with smaller sizes (in 21.8- and 32.2°-misoriented bicrystalline hBN) can match water permeation through less elongated pores of slightly larger sizes, with a concomitant ∼3-4% decrease in Na+ rejection. Simulations also predict that the water flow rate is significantly affected by interfacial electrostatic interactions. Indeed, the water flow rate is the highest when altered partial charges on B and N atoms were determined using DFT calculations, as compared to when no partial charges or bulk partial charges (i.e., charged hBN) were considered. Overall, our work on water/ion transport through nanopores in bicrystalline hBN indicates that the presence of GBs and surface charge can lead, respectively, to a decrease in the ion rejection and water permeation performance of hBN membranes.