Comparative Vision of Nonlinear Thermo-Optical Features and Third-Order Susceptibility of Mechanically Flexible Metallosupramolecular Self-Repairing Networks with Isomeric Organic Acids.

Two self-healing-type supramolecular Ni(II)-metallogels are achieved. The choice of proper low-molecular-weight organic gelators such as trans-butenedioic acid (i.e., trans-BDA) and cis-butenedioic acid (i.e., cis-BDA) and triethylamine in N,N'-dimethylformamide solvent facilitates the metallogelation process. Through rheological investigations the mechanical robustness and viscoelastic properties of synthesized metallogels are explored. An in-depth exploration of thixotropic behavior also supports their self-healing features. Notably, distinct variations in morphologies of metallogels are also ascertained through field emission scanning electron microscopy studies. Furthermore, the existence of versatile noncovalent supramolecular interactions operating throughout the metallogel network is clearly revealed via Fourier transform infrared spectroscopy. Electrospray ionization-mass studies also explore the construction protocol of individual Ni(II)-metallogels. The Z-scan measurements with a 532 nm continuous wave laser were employed to unveil the nonlinear thermo-optical response of two synthesized self-healing metallogels, i.e., trans-BDA-TEA@Ni(II) and cis-BDA-TEA@Ni(II). Crucial parameters like the nonlinear refractive index, nonlinear absorption coefficient, thermo-optical coefficient, and third-order susceptibility of these metallogels are obtained. Metallogels show negative signs for the nonlinear refractive index and the nonlinear absorption coefficient. The real parts of the third-order susceptibility for these metallogels are much greater than the imaginary parts (i.e., χR(3) > χI(3)), making such metallogels very promising for all optical-switching applications.

Suberic Acid-Based Supramolecular Metallogels of Ni(II), Zn(II), and Cd(II) for Anti-Pathogenic Activity and Semiconducting Diode Fabrication.

The importance of three synthesized metallogels of suberic acid distinctly with nickel, zinc, and cadmium acetate salts has been uncovered. For the creation of these soft materials, N,N'-dimethyl formamide was utilized as a source of the trapped solvent. The synthesized metallogels display intriguing viscoelasticity, and the interpretation of experimental parameters obtained from rheological results advocates the gel behavior. Microstructural analysis combined with energy-dispersive X-ray confirms the occurrence of individual gel-developing constituents as observed in different hierarchical microstructural patterns. Significant variations in microstructural arrangements with diverse extent of supramolecular non-covalent patterns inside gel networks were perceived through field emission scanning electron microscopy, atomic force microscopy, and transmission electron microscopy analyses. Fourier transform infrared and electrospray ionization-mass spectral analyses and powder X-ray diffraction analysis of metallogel samples of different gel-establishing ingredients help to investigate the possible supramolecular interactions dictating the metallogel scaffolds. Thermogravimetric analysis of xerogel samples was collected from the synthesized metallogels to understand the thermal stability. These gel materials were characterized by their potential antibacterial efficiency. The potency of metallogels against selective Gram-positive and Gram-negative bacteria was visualized via a spectrophotometer. Human pathogens like Klebsiella pneumoniae (MTCC 109), Salmonella typhi (MTCC 733), Vibrio parahaemolyticus, Bacillus cereus (MTCC 1272), Lactobacillus fermentum (NCDO 955), and Staphylococcus aureus (MTCC 96) are employed in this study. Apart from the biological significance, our metallogels demonstrate as incredible diode performance of fabricated semiconducting systems, which exhibit a considerable amount of non-linearity demonstrating a non-ohmic conduction mechanism at room temperature in dark conditions. Device fabrication was achieved from these metallogels employing the sandwich model with indium tin oxide-coated glass substrates/metallogel/Al structure.

Solvent-Driven Variations of Third-Order Nonlinear Thermo-Optical Features of Glutaric Acid-Directed Self-Healing Supramolecular Ni(II) Metallogels.

The generation of solvent-directed self-healing supramolecular Ni(II) metallogels of glutaric acid (i.e., Ni-Glu-DMF and Ni-Glu-DMSO) is described in this article. Polar aprotic solvents like N,N'-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) are separately entrapped into the Ni(II)-acetate salt and glutaric acid-mediated networks to attain the semisolid flexible scaffolds. The gel nature of the fabricated materials is experimentally proven through different rheological tests such as amplitude sweep, frequency sweep, and thixotropic (time sweep) measurements. The self-repairing strategy and load-bearing features of the synthesized metallogel are studied in this work. The different supramolecular noncovalent interactions working within the soft scaffold are clearly explored. The formation strategy and the microstructural features of these synthesized metallogels are scrutinized through a Fourier transform infrared (FT-IR) spectroscopy study and field-emission scanning electron microscopy (FESEM) morphological analyses. The FT-IR spectroscopy observation displays a considerable amount of shifting of the infrared (IR) peaks of the xerogel samples of both the metallogels Ni-Glu-DMF and Ni-Glu-DMSO. The electrospray ionization (ESI)-mass spectroscopy result demonstrates the plausible construction of the metallogel network. In order to examine the nonlinear optical characteristics of the two synthesized self-healing metallogels Ni-Glu-DMSO and Ni-Glu-DMF, Z-scan measurements are carried out with a continuous wave (CW) diode-pumped solid-state (DPSS) laser at 532 nm. The nonlinear refractive index, nonlinear absorption coefficient, thermo-optical coefficient, and third-order susceptibility of these metallogels were evaluated by analyzing the experimental data from the Sheik-Bahae formalism. The nonlinear thermo-optical study reveals that these solvent-dependent metallogels show negative signs of nonlinear refractive index and nonlinear absorption coefficient. The figure of merit calculated for these compounds shows good agreement for their use in nonlinear photonic devices.

Climatic factors influence the spread of COVID-19 in Russia.

The study is the first attempt to assess the role of climatic predictors in the rise of COVID-19 intensity in the Russian climatic region. The study used the Random Forest algorithm to understand the underlying associations and monthly scenarios. The results show that temperature seasonality (29.2 ± 0.9%) has the highest contribution for COVID-19 transmission in the humid continental region. In comparison, the diurnal temperature range (26.8 ± 0.4%) and temperature seasonality (14.6 ± 0.8%) had the highest impacts in the sub-arctic region. Our results also show that September and October have favorable climatic conditions for the COVID-19 spread in the sub-arctic and humid continental regions, respectively. From June to August, the high favorable zone for the spread of the disease will shift towards the sub-arctic region from the humid continental region. The study suggests that the government should implement strict measures for these months to prevent the second wave of COVID-19 outbreak in Russia.

Determining suitable machine learning classifier technique for prediction of malaria incidents attributed to climate of Odisha.

This study investigated the influence of climate factors on malaria incidence in the Sundargarh district, Odisha, India. The WEKA machine learning tool was used with two classifier techniques, Multi-Layer Perceptron (MLP) and J48, with three test options, 10-fold cross-validation, percentile split, and supplied test. A comparative analysis was carried out to ascertain the superior model among malaria prediction accuracy techniques in varying climate contexts. The results suggested that J48 had exhibited better skill than MLP with the 10-fold cross-validation method over the percentile split and supplied test options. J48 demonstrated less error (RMSE = 0.6), better kappa = 0.63, and higher accuracy = 0.71), suggesting it as most suitable model. Seasonal variation of temperature and humidity had a better association with malaria incidents than rainfall, and the performance was better during the monsoon and post-monsoon when the incidents are at the peak.

Climatic influence on the magnitude of COVID-19 outbreak: a stochastic model-based global analysis.

We investigate the climatic influence on COVID-19 transmission risks in 228 cities globally across three climatic zones. The results, based on the application of a Boosted Regression Tree algorithm method, show that average temperature and average relative humidity explain significant variations in COVID-19 transmission across temperate and subtropical regions, whereas in the tropical region, the average diurnal temperature range and temperature seasonality significantly predict the infection outbreak. The number of positive cases showed a decrease sharply above an average temperature of 10°C in the cities of France, Turkey, the US, the UK, and Germany. Among the tropical countries, COVID-19 in Indian cities is most affected by mean diurnal temperature, and those in Brazil by temperature seasonality. The findings have implications on public health interventions, and contribute to the ongoing scientific and policy discourse on the complex interplay of climatic factors determining the risks of COVID-19 transmission.

Comparative outcomes of the voltage-dependent current density, charge transportation and rectification ratio of electronic devices fabricated using mechanically flexible supramolecular networks.

In this study, we report the synthetic method of two distinct supramolecular metallogels, namely Mn-BDA and Cd-BDA, using Mn(II) acetate tetrahydrate, Cd(II) acetate dihydrate and butane-1,4-dicarboxylic acid (BDA). DMF, a polar aprotic solvent, was immobilized in both metallogel-networks for their synthesis. The metallogelation of Mn-BDA was successfully attained through the instant mixing of a Mn(II)-source and BDA in DMF solvent media. By applying ultrasonication, a Cd-BDA metallogel was prepared. The stoichiometry of gel-forming components concerning metal salts and the LMWG are accountable to obtain respective stable metallogels. Rheological parameters such as storage modulus (G') and loss modulus (G'') explored the mechanical flexibility of the synthesized metallogels through amplitude and angular frequency sweep experiments. Both the metallogels possess significant mechanical stability, which was determined by monitoring diverse gel-to-sol transition shear strain values (γ%). Distinctive morphological visualizations of both of these metallogels (i.e., Mn-BDA and Cd-BDA) were made via field emission scanning electron microscopic (FESEM) studies, demonstrating a fibrous inter-connected network with a hierarchical self-assembled arrangement for Mn(II)-based metallogels and a typical stacked-flake-like association with hierarchical motifs for Cd(II)-based metallogels. EDAX elemental mapping substantiated the presence of metallogel-forming agents such as individual metal acetate salts, BDA acting as a low-molecular weight gelator, and gel-immobilized solvents such as DMF. Furthermore, Fourier transform infrared spectroscopy and ESI-mass spectroscopy were performed for both these supramolecular metallogels. FT-IR spectroscopic and ESI-mass spectroscopic results clearly substantiate the possible non-covalent supramolecular interactions among basic molecular repeating moieties, i.e., butane-1,4-dicarboxylic acid (the low-molecular weight gelator), individual metal salts and gel-immobilized polar aprotic solvent DMF for the construction of distinct stable supramolecular metallogel-systems. The semiconducting property of the fabricated metallogels was investigated. Two Schottky diodes (SDs) composed of ITO/Cd-BDA/Al and ITO/Mn-BDA/Al in a sandwich pattern with Al serving as the metal electrode were fabricated. Both these metallogel-based devices effectively offer significant semiconducting diode features with non-linear J-V characteristics. The non-ohmic conduction protocol of the fabricated metallogel-based devices was explored. Mn-BDA and Cd-BDA metallogel-based fabricated devices have rectification ratios of 6.67 and 23.50, respectively. The gel-based diode performances were examined by observing the voltage-dependent current density, charge transportation and rectification ratio.

Causes and consequences of tipping points in river delta social-ecological systems.

The sustainability of social-ecological systems within river deltas globally is in question as rapid development and environmental change trigger "negative" or "positive" tipping points depending on actors' perspectives, e.g. regime shift from abundant sediment deposition to sediment shortage, agricultural sustainability to agricultural collapse or shift from rural to urban land use. Using a systematic review of the literature, we show how cascading effects across anthropogenic, ecological, and geophysical processes have triggered numerous tipping points in the governance, hydrological, and land-use management of the world's river deltas. Crossing tipping points had both positive and negative effects that generally enhanced economic development to the detriment of the environment. Assessment of deltas that featured prominently in the review revealed how outcomes of tipping points can inform the long-term trajectory of deltas towards sustainability or collapse. Management of key drivers at the delta scale can trigger positive tipping points to place social-ecological systems on a pathway towards sustainable development.

Real-Time Remote Patient Monitoring and Alarming System for Noncommunicable Lifestyle Diseases.

Telemedicine and remote patient monitoring (RPM) systems have been gaining interest and received adaptation in healthcare sectors since the COVID-19 pandemic due to their efficiency and capability to deliver timely healthcare services while containing COVID-19 transmission. These systems were developed using the latest technology in wireless sensors, medical devices, cloud computing, mobile computing, telecommunications, and machine learning technologies. In this article, a real-time remote patient monitoring system is proposed with an accessible, compact, accurate, and low-cost design. The implemented system is designed to an end-to-end communication interface between medical practitioners and patients. The objective of this study is to provide remote healthcare services to patients who need ongoing care or those who have been discharged from the hospital without affecting their daily routines. The developed monitoring system was then evaluated on 1177 records from MIMIC-III clinical dataset (aged between 19 and 99 years). The performance analysis of the proposed system achieved 88.7% accuracy in generating alerts with logistic regression classification algorithm. This result reflects positively on the quality and robustness of the proposed study. Since the processing time of the proposed system is less than 2 minutes, it can be stated that the system has a high computational speed and is convenient to use in real-time monitoring. Furthermore, the proposed system will fulfil to cover the lower doctor-to-patient ratio by monitoring patients from remote locations and aged people who reside in their residences.

Index-based tools for livelihood security and resilience assessment (LiSeRA) in lower Mekong Basin.

This paper presents a framework and toolkit for assessment of multi-hazard livelihood security and resilience in the Lower Mekong Basin (LMB) communities. The LMB is a subsidiary region of the Mekong region in South East Asia, and is frequently exposed to hydrometeorological hazards and anthropogenic stressors that expose and directly affect the livelihoods of more than sixty-five million people living in the region. The main purpose of the study is to support decision-making and risk management planning through integration of the concepts of livelihood security and resilience into a holistic framework, and subsequently developing an index-based toolkit for conducting assessments. Firstly, dimensions, sub-dimensions and indicators for measurement of livelihood security and resilience in the LMB were identified through comprehensive literature review and expert consultation. Then, several local workshops were conducted with various stakeholders (researchers, government officials, community people) in the LMB region to validate the indicators and generate weightages. The indicators were then arranged in a matriculated form, and the weightages were used to generate the algorithm for computing the quantitative outputs of livelihood security and resilience in study area. An Excel toolkit and a 'R' programming package were developed using the algorithm for visualization of the assessment outcomes. The proposed framework and toolkit are expected to assist researchers, government officials and development professionals in generating robust resilience assessment indices for risk informed decision-making and planning. Brief outline of the method •Livelihood security and resilience concepts were integrated to generate a holistic assessment framework and an indicator library.•Weightages for indicators were generated using the Analytical Hierarchical Process (AHP) through consultation with relevant stakeholders.•The indicator library was developed into an algorithm-based Excel and 'R' programming toolkit that provides quantitative assessment outputs.

Exploration of Variable Solvent Directed Self-Healable Supramolecular M(II)-Metallogels (M = Co, Ni, Zn) of Azelaic Acid: Investigating Temperature-Dependent Ion Conductivity and Antibacterial Efficiency.

Molecular self-assembly assisted self-healing supramolecular metallogels of azelaic acid with cobalt(II)-, nickel(II)-, and zinc(II)-based metal acetate salts were successfully fabricated. Individually, N,N'-dimethylformamide and dimethyl sulfoxide were immobilized within these distinctly synthesized soft-scaffolds of metallogels to attain their semisolid viscoelastic nature. Rheological experiments such as amplitude sweep, frequency sweep, and thixotropic measurements were executed for these metallogels to ratify their gel features. The different extents of supramolecular interactions operating within these solvent-directed metallogels were clearly reflected in terms of their distinct morphological patterns as investigated through field emission scanning electron microscopy. Comparative infrared (IR) spectral properties of metallogels along with individual metal salts and azelaic acid were analyzed. These experimental data clearly depict the significant shifting of Fourier transform (FT)-IR peaks of xerogel samples of different metallogels from the gel-forming precursors. The networks present within the soft-scaffold are evidently illustrated by the electrospray ionization-mass experimental data. The temperature-dependent ionic conductivity studies with these solvent-directed versatile metallogel systems were investigated through impedance spectroscopy. The temperature-dependent impedance spectroscopic studies clearly demonstrate that the ion-transportation within the gel matrix depends not only on the types of cations but also on the dielectric properties of the immobilized solvents. The antipathogenic effect of these metallogel systems has also been explored by testing their effectiveness against human pathogenic Gram-negative bacteria Klebsiella pneumoniae (MTCC 109) and Vibrio parahemolyticus, and Gram-positive bacteria like Bacillus cereus (MTCC 1272). These gel soft-scaffolds show no significant cytotoxicity against both the human neuroblastoma cell line-SH-SY5Y and the human embryonic kidney cell line-HEK 293.

Earthquake precursory detection using diurnal GPS-TEC and kriging interpolation maps: 12 May 2008, Mw7.9 Wenchuan case study.

This study presents an alternative vertical total electron content (VTEC) anomaly detection technique based on diurnal VTEC values. In order to assess the consistency of the results, Mw7.9 Wenchuan earthquake occurred on May 12, 2008 was chosen as case study because several researches were performed on this earthquake event. In this detection technique, the daily mean of VTEC (AVTEC) and standard deviation of diurnal VTEC (SVTEC) were adopted in the analytical process instead of quartile-based technique. The spatial distribution of VTEC was illustrated by AVTEC and SVTEC maps which created from ordinary Kriging interpolation technique. The anomalous day derived from AVTEC and SVTEC was observed on May 9, 2008. The anomalous zone significantly appeared within the earthquake preparation zone in the southeast of the epicenter. The results were corresponding to the previous studies in terms of time and space. Thus, AVTEC, SVTEC and instantaneous ionospheric maps created from ordinary Kriging interpolation technique should be an alternative approach for detecting ionospheric anomaly prior to earthquake occurrence.•Simplified seismo-ionospheric anomaly detection technique•Ionospheric distribution is modelled by ordinary Kriging interpolation maps•The results are consistent with the previous studies in terms of time and space.

Health Disparities: A Perspective on Internal Migration and Health Behavior in Sudan.

Background: Natural hazards, poor socio-economic conditions, low literacy levels, and long-standing conflicts affect traditional gold miners in Sudan and contribute to multiple health vulnerabilities. An extensive survey reveals differential health risk among internal migrant miners leading to short-, medium-, and long-term health consequences and disparities. The need to identify determinants of health behavior and limited prior research on internal migrants involved in traditional gold mining in Sudan motivated this research. Objective: To investigate potential health disparities between internal migrant workers participating in traditional gold mining and their local counterparts. Methods: Questionnaires on socio-demographic and health status in the Abideya area in the River Nile state of Sudan were administered to 211 miners. Composite score variables were devised based on existing literature and data for assessment of underlying risk determinants for the miners' vulnerability (migrants and non-migrants). Six new composite variables were constructed and subjected to analysis by immigration status. Findings: There are disparities in drivers of health behavior related to the immigration status of traditional gold miners. Access to water, sanitation, and hygiene services are common determinants for the health behavior of both internal migrant miners (p < 0.001) and their local counterparts (p < 0.001). However, knowledge (p < 0.05) and perception (p < 0.05) are additional critical determinants for the health behavior of local miners, while education (secondary, p < 0.01) is an additional modifier for the immigrants' health behavior. Conclusions: The outcomes of this field-based research suggest increased awareness and risk perceptions among migrants could improve health-related behaviors. The study advocates for policymaking and implementation of health programs at all levels to reduce health disparities between migrants and non-migrants, improving the health status of the entire community.

Global food security in the context of COVID-19: A scenario-based exploratory analysis.

This study highlights the major players in the global food balance, potential implications of COVID-19 on global food supply, and SDG-2 (zero hunger). It found that developing countries, fifteen from Africa followed by ten from Latin America, six from Oceania, and four from Asia, are the most vulnerable to changes cereal supply shocks. It concludes that the current pandemic is likely to cause transitory food insecurity across such vulnerable countries. The effects of the pandemic on food security (SDG-2) may persist longer as a combined effect of economic slowdown and increase in poverty, limiting food supply and access beyond 2020.

Intercorrelation of Major DNA/RNA Sequence Descriptors - A Preliminary Study.

A large number of alignment-free techniques of graphical representation and numerical characterization (GRANCH) of bio-molecular sequences have been proposed in the recent past years, but the relative efficacy of these methods in determining the degree of similarities and dissimilarities of such sequences have not been ascertained. OBJECTIVE: Our objective is to make an assessment of the relative efficacy of these methods in determining the degree of similarities and dissimilarities of bio-molecular sequences. METHOD: We have chosen 7 published/communicated methods that represent various classes of GRANCH techniques and computed the descriptors that are expected to characterize similarities and dissimilarities in several sets of gene sequences. We critically appraise the different methods and determine which of these yield non-redundant structural information that could be used to compute different properties of the sequences, and which are correlated enough to one another so that using the simplest representative of the group would suffice. We also do a principal component analysis (PCA) to determine how the variances in the calculated sequence descriptors are explained by the computed principal components (PCs). RESULTS: We found that some of the descriptors are strongly correlated implying a commonality of structural information encoded by them while others are distinctly separate. The PCA results show that the first three PC's explain >97% of the variances. CONCLUSION: We found that some mathematical DNA descriptors calculated by a few of these techniques correlate strongly with one another implying a redundancy in the structural information quantified by those descriptors; others are not strongly correlated with one another suggesting that they encode non-redundant sequence information. From this and our PCA results, our recommendation would be to use minimally correlated set of descriptors or orthogonal descriptors like PCs derived from the descriptor set for the characterization of nucleic acid structure and function.