Catalytic Advantage in Otto-like Two-Stroke Quantum Engines.

We demonstrate how to incorporate a catalyst to enhance the performance of a heat engine. Specifically, we analyze efficiency in one of the simplest engine models, which operates in only two strokes and comprises of a pair of two-level systems, potentially assisted by a d-dimensional catalyst. When no catalysis is present, the efficiency of the machine is given by the Otto efficiency. Introducing the catalyst allows for constructing a protocol which overcomes this bound, while new efficiency can be expressed in a simple form as a generalization of Otto's formula: 1-(1/d)(ω_{c}/ω_{h}). The catalyst also provides a bigger operational range of parameters in which the machine works as an engine. Although an increase in engine efficiency is mostly accompanied by a decrease in work production (approaching zero as the system approaches Carnot efficiency), it can lead to a more favorable trade-off between work and efficiency. The provided example introduces new possibilities for enhancing performance of thermal machines through finite-dimensional ancillary systems.

Source identification and potential health risks from elevated groundwater nitrate contamination in Sundarbans coastal aquifers, India.

In recent years groundwater contamination through nitrate contamination has increased rapidly in the managementof water research. In our study, fourteen nitrate conditioning factors were used, and multi-collinearity analysis is done. Among all variables, pH is crucial and ranked one, with a value of 0.77, which controls the nitrate concentration in the coastal aquifer in South 24 Parganas. The second important factor is Cl-, the value of which is 0.71. Other factors like-As, F-, EC and Mg2+ ranked third, fourth and fifth position, and their value are 0.69, 0.69, 0.67 and 0.55, respectively. Due to contaminated water, people of this district are suffering from several diseases like kidney damage (around 60%), liver (about 40%), low pressure due to salinity, fever, and headache. The applied method is for other regions to determine the nitrate concentration predictions and for the justifiable alterationof some management strategies.

Using unsupervised machine learning models to drive groundwater chemistry and associated health risks in Indo-Bangla Sundarban region.

Groundwater is an essential resource in the Sundarban regions of India and Bangladesh, but its quality is deteriorating due to anthropogenic impacts. However, the integrated factors affecting groundwater chemistry, source distribution, and health risk are poorly understood along the Indo-Bangla coastal border. The goal of this study is to assess groundwater chemistry, associated driving factors, source contributions, and potential non-carcinogenic health risks (PN-CHR) using unsupervised machine learning models such as a self-organizing map (SOM), positive matrix factorization (PMF), ion ratios, and Monte Carlo simulation. For the Sundarban part of Bangladesh, the SOM clustering approach yielded six clusters, while it yielded five for the Indian Sundarbans. The SOM results showed high correlations among Ca2+, Mg2+, and K+, indicating a common origin. In the Bangladesh Sundarbans, mixed water predominated in all clusters except for cluster 3, whereas in the Indian Sundarbans, Cl--Na+ and mixed water dominated in clusters 1 and 2, and both water types dominated the remaining clusters. Coupling of SOM, PMF, and ionic ratios identified rock weathering as a driving factor for groundwater chemistry. Clusters 1 and 3 were found to be influenced by mineral dissolution and geogenic inputs (overall contribution of 47.7%), while agricultural and industrial effluents dominated clusters 4 and 5 (contribution of 52.7%) in the Bangladesh Sundarbans. Industrial effluents and agricultural activities were associated with clusters 3, 4, and 5 (contributions of 29.5% and 25.4%, respectively) and geogenic sources (contributions of 23 and 22.1% in clusters 1 and 2) in Indian Sundarbans. The probabilistic health risk assessment showed that NO3- poses a higher PN-CHR risk to human health than F- and As, and that potential risk to children is more evident in the Bangladesh Sundarban area than in the Indian Sundarbans. Local authorities must take urgent action to control NO3- emissions in the Indo-Bangla Sundarbans region.

Arsenic and fluoride exposure in drinking water caused human health risk in coastal groundwater aquifers.

Groundwater (GW) is a precious resource for human beings as we depend on it as a source of fresh drinking water, agricultural practices, industrial and domestic uses, etc. Extreme exposure of arsenic (As) and fluoride (F-) concentrations along the coastal GW aquifers of "South 24 Parganas and East Medinipur" diluted the quality of GW and created serious health issues. Various chronic health disorders such as - black foot disease, fluorosis skin cancer, cardiac problems, and other water borne diseases have been noticed in these two coastal districts. The comprehensive entropy-weighted water quality index (EWQI) and health risk assessment (HRA) were applied to evaluate the quality of GW and probable health risks in the coastal districts. Monte Carlo simulation and sensitivity analysis methods were simultaneously adopted to identify the non-carcinogenic health risk assessment due to regular ingestion of contaminated GW. As the study region is densely populated and part of the Sundarbans Ramsar site, it has greater importance at the international level along with regional importance to address the GWQ of this region. The major findings of the present study highlight that almost 55% of the study area is confronting serious GW quality issues and associated probable health risk (HR) due to the intense accumulation of As and F- in the GW aquifers of the study area. Children's health is more vulnerable due to the consumption of As containing GW, and adults are highly affected due to the intake of F- bearing GW in the coastal districts. The findings of the current study will draw the attention of hydrologists, groundwater management authorities, government bodies, and NGOs to regulate and monitor the GW aquifers routinely, enhance GW quality, minimizing the health hazards and sustainable water management in a more scientific and sustainable way which must be advantageous for coastal people.

Effects of elevated arsenic and nitrate concentrations on groundwater resources in deltaic region of Sundarban Ramsar site, Indo-Bangladesh region.

An attempt has been adopted to predict the As and NO3- concentration in groundwater (GW) in fast-growing coastal Ramsar region in eastern India. This study is focused to evaluate the As and NO3- vulnerable areas of coastal belts of the Indo-Bangladesh Ramsar site a hydro-geostrategic region of the world by using advanced ensemble ML techniques including NB-RF, NB-SVM and NB-Bagging. A total of 199 samples were collected from the entire study area for utilizing the 12 GWQ conditioning factors. The predicted results are certified that NB-Bagging the most suitable and preferable model in this current research. The vulnerability of As and NO3- concentration shows that most of the areas are highly vulnerable to As and low to moderately vulnerable to NO3. The reliable findings of this present study will help the management authorities and policymakers in taking preventive measures in reducing the vulnerability of water resources and corresponding health risks.

Hydro-chemical assessment of coastal groundwater aquifers for human health risk from elevated arsenic and fluoride in West Bengal, India.

The vulnerability of groundwater in the coastal regions in terms of As, F-, and NO3- exposure is growing rapidly. Hence, the present study focused on assessing groundwater quality, ecological richness, and HR in the coastal districts of West Bengal by applying field-based CD, GWQI, ERI, and HRI techniques. After assessing the GW vulnerability, it is stated that approximately 40-50 % area of the two selected coastal district's GW is poor to very poor in quality, the ecology of GW is threatened, and human health is faced serious risk for both dry and wet season. The Wilcox and USSL diagram verified that nearly 50 % GW aquifers of coastal district of West Bengal are not fit for irrigation and drinking. The findings of this study will be beneficial to manage and control groundwater vulnerability in the coastal regions for water scientists, policy makers, and researchers as well in sustainable way.

Strict lockdown measures reduced PM2.5 concentrations during the COVID-19 pandemic in Kolkata, India.

The COVID-19 situation is a critical state throughout the world that most countries have been forced to implement partial to total lockdown to control the COVID-19 disease outbreak. And displays the natural power to rejuvenate herself without the interference of human beings. So, the top-level emergency response including full quarantine actions are significant measures against the COVID-19 and resulted in a notable reduction in PM2.5 in the atmosphere. India was severely attacked by COVID-19, and as a result, the Government of India has imposed a nationwide lockdown from 24th March (2020) to 30th May (2020) in different phases. The COVID-19 outbreak and lockdown had a significant negative impact on India's socioeconomic structure but had a positive impact on environmental sustainability in terms of improved air quality due to the 68 days of the shutdown of India's industrial, commercial, construction, and transportation systems. The current study looked at the spatio-temporal changes in PM2.5 concentrations at different air quality monitoring stations (AQMS) in Kolkata during the COVID-19 period. The study revealed that the average concentration of PM2.5 (µg/m3) was slightly high (139.82) in the pre-lockdown period which was rapidly reduced to 37.77 (72.99% reduction) during the lockdown period and it was further increased (137.11) in post-lockdown period. The study also shows that the average concentration of PM2.5 was 66.83 in 2018, which slightly increased to 70.43 (5.39%) in 2019 and dramatically decreased to 37.77 (46.37%) in the year 2020 due to the COVID-19 outbreak and lockdown. The study clearly shows that air quality improves during lockdown periods in Kolkata, but it is not a permanent solution rather than temporary. Therefore, it is necessary to make the proper policies and strategies by policymakers and government authorities, and environmental scientists to maintain such good air quality by controlling several measures of air pollutants.

Fluctuation-dissipation relations for thermodynamic distillation processes.

The fluctuation-dissipation theorem is a fundamental result in statistical physics that establishes a connection between the response of a system subject to a perturbation and the fluctuations associated with observables in equilibrium. Here we derive its version within a resource-theoretic framework, where one investigates optimal quantum state transitions under thermodynamic constraints. More precisely, we first characterize optimal thermodynamic distillation processes, and then we prove a relation between the amount of free energy dissipated in such processes and the free-energy fluctuations of the initial state of the system. Our results apply to initial states given by either asymptotically many identical pure systems or an arbitrary number of independent energy-incoherent systems, and they allow not only for a state transformation but also for the change of Hamiltonian. The fluctuation-dissipation relations we derive enable us to find the optimal performance of thermodynamic protocols such as work extraction, information erasure, and thermodynamically free communication, up to second-order asymptotics in the number N of processed systems. We thus provide a first rigorous analysis of these thermodynamic protocols for quantum states with coherence between different energy eigenstates in the intermediate regime of large but finite N.

para-Aminobenzoic acid-capped hematite as an efficient nanocatalyst for solvent-free CO2 fixation under atmospheric pressure.

Utilization of carbon dioxide by converting it into value-added chemicals is a sustainable remedy approach that stipulates abundant, cheap, non-toxic and efficient catalytic materials. In this study, we have demonstrated the use of para-aminobenzoic acid-capped hematite (PABA@α-Fe2O3) as an efficient nanocatalyst for the conversion of epoxides to cyclic carbonates utilizing CO2. The developed PABA@α-Fe2O3 nanocatalyst along with a cocatalyst, tetrabutylammonium iodide (TBAI), was able to convert a variety of epoxide substrates into their corresponding cyclic carbonates under atmospheric pressure and solvent-free conditions. The efficient catalytic activity of the material is attributed to the synergistic effect between α-Fe2O3 and the amine group of the PABA molecule present on the surface. Furthermore, the recyclability study and post-catalytic analysis revealed that the developed catalyst can be used for multiple catalytic cycles due to the stable and robust nature of the nanocatalyst. The choice of the PABA@α-Fe2O3 nanocatalyst is indeed a sustainable approach from the CO2 capture and utilization point of view.

Triazine-based Organic Polymer-catalysed Conversion of Epoxide to Cyclic Carbonate under Ambient CO2 Pressure.

In this work we have achieved epoxide to cyclic carbonate conversion using a metal-free polymeric catalyst under ambient CO2 pressure (1.02 atm) using a balloon setup. The triazine containing polymer (CYA-ANIS) was prepared from cyanuric chloride (CYA-Cl) and o-dianisidine (ANIS) in anhydrous DMF as solvent by refluxing under the N2 gas environment. The presence of triazine and amine functional groups in the polymer results in the adsorption of CO2 up to 7 cc/g at 273 K. This inspired us to utilize the polymer for the conversion of a series of functionalised epoxides into their corresponding cyclic carbonates in the presence of tetrabutyl ammonium iodide (TBAI) as co-catalyst. The product has wide range of applications like solvent in lithium ion battery, precursor for polycarbonate, etc. The catalyst was efficient for the conversion of different mono and di-epoxides into their corresponding cyclic carbonates under atmospheric pressure in the presence of TBAI as co-catalyst. The study indicates that epoxide attached with electron withdrawing groups (like, CH2 Cl, glycidyl ether, etc.) displayed better conversion compared to simple alkane chain attached epoxides. This is mainly due to the stabilization of electron rich intermediates produced during the reaction (e. g. epoxide ring opening or CO2 incorporation into the halo-alkoxide anion). This catalyst mixture was capable to maintain its reactivity up to five cycles without losing its activity. Post catalytic characterization clearly supports the heterogeneous and recyclable nature of the catalyst.

Retinol Levels in Serum and Chronic Skin Lesions of Atopic Dermatitis.

BACKGROUND: Atopic dermatitis (AD) is a common childhood dermatosis and a distressing cause of morbidity. The pathogenesis of AD is known to be associated with disorders of immune response and defect in antioxidant defense, genetic predisposition, environmental triggers, psychosomatic factors, and other mechanisms. Retinol has immunomodulatory and antioxidant effects, thus may have a protective role in AD. OBJECTIVE: The objective of this study was to evaluate the correlation of retinol levels in skin lesions and serum, with AD. MATERIALS AND METHODS: The study was a hospital-based, case-control study. Punch biopsy from the skin and venous blood of 86 participants (including 43 cases and 43 controls) were assayed for retinol levels by a reversed-phase high-performance liquid chromatography method. Analysis of data was performed using appropriate statistical methods. RESULTS: Skin and serum retinol levels were highly significantly decreased in patients in respect to that of controls. CONCLUSION: Retinol levels were decreased in AD. Retinol estimation may be used as a promising parameter for the elaboration of treatment strategy and monitoring.

Knowledge and perception regarding clinical trials among doctors of government medical colleges: A questionnaire-based study.

AIMS: By virtue of being a specialized field by itself, the science of clinical trials (CTs) may not be well understood by doctors who are not specifically trained in it. A lack of knowledge may translate to a negative perception toward CT. With the idea of getting a situational snapshot, we estimated the knowledge and perception of CTs among doctors from government medical colleges of West Bengal who are not trained on CT in their postgraduate curriculum. Several determinants of knowledge and perception regarding CT were also evaluated. METHODS: We have quantified the knowledge and perception of CTs by a structured validated questionnaire. Development and validation of the questionnaire was performed prior to the study. RESULTS: Among 133 participants, 7.5% received focused training on CT and 16.5% participated in CTs as investigators. Majority of the doctors were unfamiliar with the basic terminologies such as, "adverse event" and "good clinical practice." Encouragingly, 93.3% doctors advised that a detailed discussion of CT methodology should be incorporated in the under graduate medical science curriculum. They had an overall positive attitude toward CTs conducted in India, with a mean score that is 72.6% of the maximum positive score. However, a large number of the doctors were skeptical about the primary motivation and operations of pharmaceutical industry sponsored CTs, with 45% of them believing that patients are exploited in these sponsored CTs. CONCLUSION: Participant doctors had a basic knowledge of CT methodology. The study has revealed specific areas of deficient knowledge, which might be emphasized while designing focused training on CT methodology.

Cardiofaciocutaneous Syndrome: Case Report of a Rare Disorder.

Cardiofaciocutaneous syndrome or CFC syndrome is a rare genetic disorder first described in 1986. It is one of the RASopathies involving multiple organs particularly the heart, skin and face affecting males and females equally. The phenotypic features overlap with 2 other conditions, the Noonan and Costello syndrome. We report on a 22-month-old boy with CFC syndrome presenting with typical craniofacial appearance, heart defects, ectodermal abnormalities, growth failure and developmental delay. Estimated population of affected individuals worldwide is a few hundreds.

Enantiodivergent synthetic entry to the quinolizidine alkaloid lasubine II.

Intramolecular cycloaddition of the syn- and the anti-nitrone 9 and 13 leads stereoselectively to the azabicyclic compounds 10 and 14 which may provide access to both enantiomers of the quinolizidine alkaloid lasubine II.