Search

Prediction of Tropical cyclones (TCs), particularly intensity prediction, has always been challenging for climate researchers due to the complicated physical mechanisms in TC dynamics and the way it interacts with upper-ocean and atmospheric circulation. Furthermore, the available data set over the North Indian Ocean (NIO) is also very limited for Machine Learning (ML) model development. Here, we demonstrated a simple yet robust hybrid architecture leveraging a Convolutional Neural Network for automated prediction of the intensity of the cyclone based on IR satellite imagery of 2000–2022. The model comprises a binary classifier, a multiclass classifier, a YOLOv3 based cyclone detector and a regression module. The paper also highlights the discrepancy between the results of independent testing wherein training is done on 2000 to 2019 dataset and tested on 2020 to 2022 dataset, as well as the outcomes of a stratified train-test split performed over the entire dataset using a 70:15:15 ratio for training, validation and testing, respectively. The model is tuned for the NIO region with a binary classification accuracy score of 98.4% (± 0.003), multiclass classification accuracy of 63.83% (± 1.3) and RMSE of 16.2 (± 0.9) knots on stratified split. The results highlight the careful interpretation of the DL model's performance when applied to time series problems. Additionally, it discusses the limitations stemming from the dataset's small size and the challenges posed by the 5 kt resolution of the best track intensity estimation from the Indian Meteorological Department (IMD). The internal representations learned by the model through feature maps analysis were studied, shedding light on the model's decision-making process. The study underscores the need for further data accumulation and highlights avenues for enhancing model performance in the future. [ABSTRACT FROM AUTHOR]

The current study has investigated the thunderstorm induced atmospheric gravity waves (AGWs) over Indian region based on the perturbation signatures in ionospheric total electron content (TEC) measurement. Robust traveling ionospheric disturbance (TID) signature has been identified along the east side of the thunderstorm affected area. Neutral wind was found to have a favorable impact in this aspect for a certain time duration of the day by modulating the vertical wavelength. The role of temperature was analyzed in terms of kinematic viscosity which is a crucial component, especially over tropical region, for wave dissipation and reflection along its propagation path. Ray tracing algorithm is also applied with varying kinematic viscosity and thermal diffusivity for retrieval of possible ray paths and source location of observed waves. A statistical investigation has been carried out to identify the dissipation altitude of observed waves along the ray paths. It has been found that all waves dissipated at almost a constant altitude for a specific kinematic viscosity and above this altitude vertical wavelength was found to decrease. The ray paths interacted at a common point which was located at about 125 km altitude and was very close to the region of maximum lightning activity. It can also be noted that the observed phase velocities can't be achieved by a wave below the turbopause. It indicates that the observed waves were excited from a secondary source and not directly connected to convective system. The study provides an in‐depth analysis of mesoscale system induced gravity wave propagation and dissipation over tropical region. Plain Language Summary: Mesoscale convective systems in tropical regions are key sources of low‐frequency atmospheric gravity waves (GWs). GWs usually generates above thunderstorm altitudes and propagates to ionospheric heights through dissipation and atmospheric filtering. This is one of the first study about the propagation mechanism of thunderstorm‐generated GWs at thermospheric altitude over the Indian region. The concentric source of the wave was evidenced by concentric rings in traveling ionospheric disturbance and phase velocity Vp $\left({V}_{p}\right)$ trends which coincides with high lightning location. It is also observed that wave with Vp ${V}_{p}$ above 250 m/s were unable to propagate below 100 Km and indicate the secondary source of the gravity wave at thermospheric altitudes which was not directly related with the thunderstorm activity. The effect of background temperature on the propagation mechanism was tested by examining the role of kinematic viscosity on wave dissipation. The maximum momentum fluxes were found around 260 km altitude for a specific kinematic viscosity profile. Interestingly, the ray‐tracing validation fails one scale height above this altitude, aligning with theories of wave dissipation or reflection. Additionally, it was also observed that all waves interacted at a common point in both horizontal and temporal domains. This is one of the key finding of this investigation. Key Points: The study presents signature of thunderstorm induced gravity wave above lower thermospheric altitudePhase velocity and intrinsic period increased linearly from thunderstorm locationAn almost unique wave dissipation altitude found for all waves for a specific kinematic viscosity [ABSTRACT FROM AUTHOR]

Coronal mass ejections (CMEs) that cause geomagnetic disturbances on the Earth can be found in conjunction with flares, filament eruptions, or independently. Though flares and CMEs are understood as triggered by the common physical process of magnetic reconnection, the degree of association is challenging to predict. From the vector magnetic field data captured by the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO), active regions are identified and tracked in what is known as Space Weather HMI Active Region Patches (SHARPs). Eighteen magnetic field features are derived from the SHARP data and fed as input for the machine-learning models to classify whether a flare will be accompanied by a CME (positive class) or not (negative class). Since the frequency of flare accompanied by CME occurrence is less than flare alone events, to address the class imbalance, we have explored the approaches such as undersampling the majority class, oversampling the minority class, and synthetic minority oversampling technique (SMOTE) on the training data. We compare the performance of eight machine-learning models, among which the Support Vector Machine (SVM) and Linear Discriminant Analysis (LDA) model perform best with True Skill Score (TSS) around 0.78 ± 0.09 and 0.8 ± 0.05, respectively. To improve the predictions, we attempt to incorporate the temporal information as an additional input parameter, resulting in LDA achieving an improved TSS of 0.92 ± 0.04. We utilize the wrapper technique and permutation-based model interpretation methods to study the significant SHARP parameters responsible for the predictions made by SVM and LDA models. This study will help develop a real-time prediction of CME events and better understand the underlying physical processes behind the occurrence. [ABSTRACT FROM AUTHOR]

Climatic changes and the recent surge in weather extremities are alarming concerns for society today. Tropical squall events with extremely heavy rainfall and lightning are among the very severe ones among such activities. Usually, squalls have a leading convective edge followed by a stratiform trail; however, the reverse is also observed in rare cases. This work presented a thorough study on a conventional and an unconventional squall with nearly similar severities from a tropical location, Kolkata. The study reports notably high wind gusts and lightning activities during both events, with the latter one showing higher values. The CAPE increase and OLR drops were significant in both the cases. Breakage of storm front were noticed in the first squall, which possibly resulted in higher CAPE surrounding the study location even though the localised value was slightly larger during the second event. The unconventional squall having a shorter life cycle showed weaker vertical wind shear. The cloud system during the second squall structure showed dominance of smaller cloud particles and lower cloud top pressure than the first event, whereas the cloud mask fraction and cloud water path were large in this case. The rain microphysics has been studied for the two said events and a greater number of drops has been observed in the reflectivity through region than in the stratiform phase for the squall with trailing convective line, unlike the one with conventional structure. The rain microphysical properties showed clearly distinguishable behaviour during the three phases of the squall passage for both the events. Exceptionally high a values in empirical relation between Z and R were noticed in both the cases. The study reports higher path attenuation during the first event. The study can be useful in improving the understanding of the efficiency of different atmospheric and precipitation microphysical features in the predictability of a mesoscale system. Research highlights: The current work has presented a thorough analysis of two tropical squalls with different organisational modes. The variation in associated weather variables has been studied for the two events. A thorough study of precipitation microphysics has been carried out for the two squalls. The conventional factors used for prediction of mesoscale systems were analysed in detail for these cases to understand the efficiency of these elements in prediction of an unconventional convective system like a squall with a leading stratiform edge studied here. [ABSTRACT FROM AUTHOR]

Lightning is one of the most severe weather events causing significant loss of human lives and resources. Increasing number of lightning fatalities due to recent climatic changes is emerging out to be a serious concern for India during last few years. Proper characterization and parameterization of the same, therefore, is extremely crucial. However, lightning is an extremely dynamic phenomenon having enormous spatio‐temporal inhomogeneity especially over such a vast country like India with varied topographic and climatological features. Therefore, proper parameterization of lightning activity over India needs consideration of different lightning climatologies. This study has attempted to resolve the issue by regionalizing Indian subcontinent in different lightning climatologies based on lightning density and associated atmospheric variables that is, CAPE, specific humidity at different pressure levels, temperature, k index and cloud particle size and identified seven distinct lightning climatologies over India. A regression model is proposed for estimating the annual and seasonal (monsoon and pre‐monsoon) lightning activities over the seven resulting lightning zones based on the said atmospheric variables using machine learning techniques. Four machine learning models have been tested among which Random forest has shown the best accuracy. The regression model has shown an R‐squared score of 0.81 during monsoon season and 0.71 during the pre‐monsoon. The atmospheric features based on their influences on the lightning activity in these seven climatologies has been ranked which presented the evidences of largely varied interplay between different atmospheric variables and lightning over different parts of the country and during different seasons. [ABSTRACT FROM AUTHOR]

Mechanochemistry has proven to be an excellent green synthesis method for preparing organic, pharmaceutical, and inorganic materials. Mechanocatalysis, inducing a catalytic reaction by mechanical forces, is an emerging field because neither external temperature nor pressure inputs are required. Previous studies reported enhanced catalytic activity during the mechanical treatment of supported gold catalysts for CO oxidation. So far, the processes inside the milling vessel during mechanocatalysis could not be monitored. In this work, the results of high‐energy operando X‐ray powder diffraction experiments and online gas analysis will be reported. A specific milling setup with a custom‐made vessel and gas dosing system was developed. To prove the feasibility of the experimental setup for operando diffraction studies during mechanocatalysis, the CO oxidation with Au@Fe2O3 as a catalyst was selected as a well‐known model reaction. The operando studies enabled monitoring morphology changes of the support as well as changes in the crystallite size of the gold catalyst. The change of the crystal size is directly correlated to changes in the active surface area and thus to the CO2 yield. The studies confirm the successful implementation of the operando setup, and its potential to be applied to other catalytic reactions. [ABSTRACT FROM AUTHOR]

The pressing need for accurate and reliable precipitation measurements and forecasting poses theoretical and technological problems. Remote-sensing instruments with increased coverage and sensitivity (such as space-borne and ground-based radar) are available; however, their full exploitation requires physical calibration and validation based on a deep knowledge of precipitation microphysics. This study reports a detailed analysis of the evidence of non-terminal velocities in a mid-latitude (Bologna, Italy) and a tropical location (Kolkata, India). The data from two identical disdrometers OTT-Parsivel2 were analyzed to shed light on the nature of the raindrops that fall at a velocity that is significantly higher (i.e., super-terminal drops) or lower (sub-terminal drops) than the terminal velocity expected for the raindrop sizes. The results show a significant fraction of super- and sub-terminal drops in both locations. The percentages of both super- and sub-terminal drops were higher in Kolkata. However, the difference was more notable for convective rain. The percentages of both super- and sub-terminal drops were found to be high within a drop diameter of 1 mm. The number of sub-terminal drops seemed to increase with an increase in diameter for drops larger than ~2.5 mm. The natural rain in Bologna showed stronger evidence of drop break-up in correspondence with the evolution of non-terminal velocities. Moreover, this study once again pointed toward the fact that the process of break-up cannot be neglected in natural rain of tropical or mid-latitude locations. We found that 7% and 10% of rain samples in Bologna and Kolkata seemed to be subjected to drop break-up. The results indicate that radar measurements of rain in the tropics or mid-latitude regions, relying on the Gunn–Kinzer relationship between velocity and diameter, should be verified by observations of disdrometers for a high precision QPE. [ABSTRACT FROM AUTHOR]

Validation of synthetic storm technique (SST) has been done for prediction of attenuation due to rain over a hilly, high-rainfall, tropical location, Shillong (25°N, 91°E), India. In this letter, considering one year of rain attenuation and rain rate data shows that SST predicted attenuation overestimates while comparing the available experimental result. Storm speed has been found to have no significant effect on the attenuation prediction by SST. Second-order rain attenuation prediction, i.e., prediction of fade slope, has also been studied. Fade slope is found to have been overestimated by SST for all categories of rain events at 20.2- and 30.3-GHz frequency. Exceedance plot of fade duration by SST shows an overestimation for higher frequency and underestimation for lower frequency. [ABSTRACT FROM AUTHOR]

The effect of climate change on precipitation pattern is emerging out as a serious global challenge. However, the quantification and assessment of the climate change effect on precipitation are a challenging issue given the spatio-temporal inhomogeneity of rainfall. Previous studies mostly used only rain intensity information for the identification of climate change signature by selecting homogeneous rain regions. Rain climatology, however, has several other important characteristics like occurrence of multiple rain type, occurrence of extreme rain events and their spatial distribution. The present study provides a novel approach to combine satellite data with ground measurements for addressing this issue. In this study, the Indian subcontinent has been divided into homogeneous regions based on six different rain features, obtained from ground observations and TRMM satellite measurements of 12 years, using K-medoid clustering technique. The rain features showed distinguishable patterns in the resulting nine homogeneous rain zones and distinct behavioural patterns in the inter-relationships between the various rain features. To verify the consistency of the proposed regionalization, the recent changes in mean monsoon rain rates are then studied using 40 years of rain gauge measurements for these regions. Increasing trends in monsoon rain are observed in two homogeneous regions whereas five of them have shown decreasing signature of rain intensity. Although the present study focused only on monsoon rain over India, the results indicate the suitability of the proposed method as an efficient technique of identifying homogeneous region for other seasons and locations as well. [ABSTRACT FROM AUTHOR]

Titanium is an important alloying addition to γ/γ′ cobalt-based superalloys that enhances the high temperature microstructural stability and make the alloys lighter. In this work, we probe the role of Ti composition on the phase stability and oxidation behavior of Co–30Ni–10Al–8Cr–5Mo–2Nb superalloys. With Ti addition, the γ′-solvus temperature is enhanced and the γ′-precipitate shape changes from spherical to rounded cuboids. Addition of 4 at. pct Ti to the alloy promotes topologically-close-packed (TCP) phase formation that are rich in Co, Cr, and Mo. During oxidation at 900 °C, Ti was found to facilitate the early formation of passivating oxide layers (spinel CoCr2O4/CoAl2O4) on the exposed surfaces, however, it was not effective in reducing the oxidation-induced mass gain. Microstructural analysis reveals that Ti delays the Al2O3 layer formation eventually leading to faster oxidation kinetics. Additionally, we also found formation of (Ti,Nb)N in the γ′ denuded zones near the alloy-oxide interface. [ABSTRACT FROM AUTHOR]

This article implements a Convolutional Neural Network (CNN)-based deep-learning model for solar-wind prediction. Images from the Atmospheric Imaging Assembly (AIA) at 193 Å wavelength are used for training. Solar-wind speed is taken from the Advanced Composition Explorer (ACE) located at the Lagrangian L1 point. The proposed CNN architecture is designed from scratch for training with four years' data. The solar-wind has been ballistically traced back to the Sun assuming a constant speed during propagation, to obtain the corresponding coronal-intensity data from AIA images. This forecasting scheme can predict the solar-wind speed well with a RMSE of 76.3 ± 1.87 km s−1 and an overall correlation coefficient of 0.57 ± 0.02 for the year 2018, while significantly outperforming benchmark models. The threat score for the model is around 0.46 in identifying the HSEs with zero false alarms. [ABSTRACT FROM AUTHOR]

Objectives: "Surviving Sepsis Campaign: International Guidelines for Management of Sepsis and Septic Shock: 2016" provides guidelines in regard to prompt management and resuscitation of sepsis or septic shock. The study is aimed to assess the robustness of randomized controlled trials (RCTs) that formulate these guidelines in terms of fragility index and reverse fragility index. Method: RCTs that contributed to these guidelines having parallel two-group design, 1:1 allocation ratio, and at least one dichotomous outcome were included in the study. The median fragility index was calculated for RCTs with significant statistical outcomes, whereas the median reverse fragility index was calculated for RCTs with nonsignificant statistical results. Results: Hundred RCTs that met the inclusion criteria were analyzed. The median fragility index was 5.5 [95% confidence interval (CI) 1--30] and median reverse fragility index was 13 (95% CI 12.07--16.8) at a p value of 0.05. The median reverse fragility index was 16 (95% CI 10--26) at a p value of 0.01. Most of the RCTs included in this analysis were of good quality, having a median Jadad score of 6. Conclusion: This analysis found that the surviving sepsis guidelines were based on highly robust RCTs with statistically insignificant results and on some moderately robust RCTs with statistically significant results. RCTs with statistically insignificant results were more robust than RCTs with statistically significant results in regard to these guidelines. [ABSTRACT FROM AUTHOR]

Propagation impairment due to rain is one of the most critical considerations for satellite communication (Satcom) links above 10 GHz. The existing studies at tropical and equatorial regions are mostly focused on rain attenuation characteristics derived from rainfall characteristics, which may not be adequate to represent actual rain attenuation characteristics. The experimental studies on the same topic are very scattered and limited over these regions. Consolidating experimental results can provide a good background for rain attenuation studies over these regions and will be helpful to validate new models as well as devise new strategies to combat high fade condition. In this article, we attempt to review and summarize the performance of different rain attenuation models validated against satellite signal measurements at tropical and equatorial locations. This will serve as a benchmark for understanding the rain attenuation characteristics over this part of the globe. [ABSTRACT FROM AUTHOR]

Sodium 3‐amino‐2‐hydroxyanthraquinone‐1‐sulphonate (AQS) is an analogue of the anthracycline based chemotherapeutic drugs that was prepared as a part of the reported study. As the surfactant micelles mimics the biological membrane the present study comprises the interaction of AQS with an anionic surfactant, sodium dodecyl sulfate (SDS) in aqueous media at pH 7.4 which was monitored by using UV–Visible spectroscopy. The aim of the study is to see whether the present molecule penetrates a biological membrane. Different binding parameters like binding constant, partition coefficient, and corresponding Gibbs free energies of the interaction of AQS and its distribution between aqueous media and SDS micelles were measured. The study revealed that hydrophobic interactions play the most important role in binding of AQS to SDS micelles. To see whether AQS really permeates a biological membrane and induces apoptosis, it was allowed to interact with A549 human lung cancer cells. This study established the fact that AQS results apoptosis by means of nucleation into this cell. [ABSTRACT FROM AUTHOR]

Purpose: The present study systematically searched important medical databases, assessed the quality of available pieces of evidence, and performed a meta-analysis to test the efficacy of different therapeutic options currently available for treating COVID-19. Materials and methods: PubMed, CNKI, LILACS, Koreamed, WHO clinical trial registry, and medRxiv were searched since December 2019. Any observational or controlled study that tested the efficacy of any pharmacological intervention in COVID-19 patients either prospectively or retrospectively was included in the qualitative analysis. We assessed outcomes as dichotomous variables, i.e., a patient having a positive clinical outcome. Relative risks/risk ratios (RR) having a 95% confidence interval (CI) were derived. Studies conforming to inclusion criteria were pooled using the random-effect model. Results: Nine trials on hydroxychloroquine (HCQ), six studies on antiviral, four studies on monoclonal antibodies, two on corticosteroids, two on convalescent plasma (CP), and one on interferon-α2b were included in the systematic review. Meta-analysis containing six scientific trials and analyzing 522 patients revealed that the relative risk of positive clinical outcomes with HCQ treatment was 1.042 (95% CI, 0.884 to 1.874) with a number needed to treat (NNT) of 12.6. A meta-analysis of two studies analyzing 285 patients showed that the relative risk of clinical resolution with lopinavir and ritonavir combination was 1.152 (95% CI 0.709 to 1.87). Out of various antiviral used, the only remdesivir showed a positive result in a case series. Monoclonal antibodies showed decreased C-reactive protein, decreased oxygen, and ventilator requirements. A corticosteroid may increase mortality with increased dose. Two small case series on CP showed some promising results. Conclusion: The study showed slightly favorable results with HCQ, monoclonal antibodies, remdesivir, and CP in treating COVID-19 patients. Further research is warranted in establishing the efficacy of studied interventions. [ABSTRACT FROM AUTHOR]

Navigation satellites provide a good opportunity to monitor both ionospheric and tropospheric conditions by using propagation delays in the L-band signal. However, the availability of S-band frequency in the Indian Regional Navigation Satellite System, Navigation with Indian Constellation (NavIC), provides a unique opportunity to utilize signal strength for monitoring thunderstorms. This article, for the first time, demonstrates that NavIC satellite signal strength measurements can be used to detect thunderstorms. A dynamic time warping technique has been used to detect the presence of thunderstorm cloud systems. The method has been tested with several case studies in Kolkata using one-year measurements. The results indicate suitability of such techniques for monitoring and forecasting of thunderstorms using a navigation satellite. [ABSTRACT FROM AUTHOR]

Noise leads to the ambiguity in regions of interest detection by corrupting the pixel information and is a vital problem in image processing domain. A novel hybrid technique based on fuzzy filtering and fuzzy thresholding is proposed here to extract the object regions accurately in presence of Gaussian noises. The proposed method is automated, does not need any parameter tuning as well does not need prior knowledge of the image or noise. An asymmetrical triangular fuzzy filter with median center coupled with a thresholding based on fuzziness minimization technique are implemented for this purpose. The fuzzy thresholding technique helps to classify the pixels with low signal-to-noise ratio (SNR) caused either due to noise or by the application of noise removal process. The proposed technique is applied in benchmark images corrupted by noises and are compared with some of the popular algorithms of object detection. The results indicate that the proposed method has superior performance in terms of peak signal-to-noise ratio (PSNR) and mean square error (MSE) value for images corrupted with Gaussian noises with standard deviation upto 1.5. [ABSTRACT FROM AUTHOR]

Two vanadium(V) Schiff base complexes, [VO2L1] (1) and [VO2L2] (2) [where HL1 = 2-((2-morpholinoethylimino)methyl)-6-ethoxyphenol and HL2 = 2-((2-(dimethylamino)ethylimino)methyl)-4-bromophenol], were synthesized and characterized by elemental and spectral analysis. The structures of both complexes were confirmed by single-crystal X-ray diffraction studies. To investigate the redox properties of the complexes, electrochemical measurements were performed in solution. Density functional theory (DFT) calculations have been performed using hybrid functional PBE0. The DFT optimized results were found to agree well with the experimental results. Topological features derived from the Bader's theory of atoms in molecules (AIM) approach have also been applied. Phenoxazinone synthase like activities (conversion of o-aminophenol to 2-aminophenoxazine-3-one) of both complexes were investigated spectrophotometrically. [ABSTRACT FROM AUTHOR]

Background: The accuracy of respiratory variation of the inferior vena cava (rvIVC) in predicting fluid responsiveness, particularly in spontaneously breathing patients is unclear.Objectives: To consider the evidence to support the accuracy of rvIVC in identifying patients who are unlikely to benefit from fluid administration.Design: Systematic review and meta-analysis.Data Source: We searched MEDLINE, EMBASE, Cochrane Library, KoreaMed, LILCAS and WHO Clinical Trial Registry from inception to June 2017.Eligibility Criteria: Case-control or cohort studies that evaluated the accuracy of rvIVC in living adult humans were included. A study was included in the meta-analysis if data enabling construction of 2 × 2 tables were reported, calculated or could be obtained from authors and met the above cited criteria.Result: A total of 23 studies including 1574 patients were included in qualitative analysis. The meta-analysis involved 20 studies and 761 patients. Pooled sensitivity and specificity of rvIVC in 330 spontaneously breathing patients were 0.80 [95% confidence interval (CI) 0.68 to 0.89] and 0.79 (95% CI 0.60 to 0.90). Pooled sensitivity and specificity of rvIVC in 431 mechanically ventilated patients were 0.79 (95% CI 0.67 to 0.86) and 0.70 (95% CI 0.63 to 0.76).Conclusion: Decreased inferior vena caval respiratory variation is moderately accurate in predicting fluid unresponsiveness both in spontaneous and mechanically ventilated patients. The findings of this review should be used in the appropriate clinical context and in conjunction with other clinical assessments of fluid status.Identifier: CRD 42017068028. [ABSTRACT FROM AUTHOR]

Abstract: Site diversity is one of the few fade mitigation techniques that are actively explored to overcome the serious fading condition encountered in high‐frequency satellite communication, particularly over tropical regions. However, the study of site diversity performance is limited over tropical regions due to unavailability of simultaneous fade measurements from multiple locations as well as the lack of data on spatial rain pattern from radar measurements. We propose here a copula‐based Bayesian approach to study the site diversity performance utilizing only a single location's drop size distribution measurement. Study of diversity performance has been done for Ahmedabad, India, utilizing 3 years of disdrometer data. Effects of frequency, elevation angle, and site separation on diversity gain are investigated using the proposed method. Results are compared with two ITU‐R models, site diversity results from Italy, a temperate region, and Singapore, another tropical location. The spatial correlation obtained through this technique is also compared with radar observations in Oklahoma, a totally different climatic regime. The simple ITU‐R model is found to be underpredicting the diversity gain significantly for the present location whereas the explicit ITU‐R model shows overprediction above 8 dB for single‐site rain attenuation values. Comparison with measurements at Italy shows similar diversity gains for low single‐site attenuation values. The results reported for Singapore matches well with the present method. The study indicates room for improvement in the present ITU‐R model considering the different nature of tropical rain and that the proposed method is suitable for such a purpose. [ABSTRACT FROM AUTHOR]

Characterization of precipitation is important for proper interpretation of rain information from remotely sensed data. Rain attenuation and radar reflectivity (Z) depend directly on the drop size distribution (DSD). The relation between radar reflectivity/rain attenuation and rain rate (R) varies widely depending upon the origin, topography, and drop evolution mechanism and needs further understanding of the precipitation characteristics. The present work utilizes 2 years of concurrent measurements of DSD using a ground-based disdrometer at five diverse climatic conditions in Indian subcontinent and explores the possibility of rain classification based on microphysical characteristics of precipitation. It is observed that both gamma and lognormal distributions are performing almost similar for Indian region with a marginally better performance by one model than other depending upon the locations. It has also been found that shape-slope relationship of gamma distribution can be a good indicator of rain type. The Z-R relation, Z = ARb, is found to vary widely for different precipitation systems, with convective rain that has higher values of A than the stratiform rain for two locations, whereas the reverse is observed for the rest of the three locations. Further, the results indicate that the majority of rainfall (>50%) in Indian region is due to the convective rain although the occurrence time of convective rain is low (<10%). [ABSTRACT FROM AUTHOR]

A dimeric complex of Cu(ii) with tinidazole characterized earlier was used to study radiosensitizing attributes. Studies reveal that the complex is better than tinidazole in sensitizing radiation-induced damage of nucleic acid bases uracil and thymine, radiation-induced double strand modification of calf thymus DNA and modification of DNA within MCF-7 breast cancer cells. The unique aspect of this study is that in spite of a substantial decrease in the generation of the nitro-radical anion (NO2Ṗ−) following complex formation of tinidazole with Cu(ii), no decrease was observed in the radiosensitizing attribute of nitroimidazoles. Rather the complex was clearly ahead of tinidazole with regard to radiosensitization. Hence, complex formation of important drug molecules are an advantage since it helps to target DNA better. This study serves as a good example where a common intermediate (NO2Ṗ−) responsible for efficacy as well as toxic side effects can be suitably tuned in its generation using a modified form of 5-nitroimidazole (here tinidazole) to be able to strike the correct balance between efficacy and toxic side effects. [ABSTRACT FROM AUTHOR]

India though being the birthplace of the ancient science of sex, it is really a matter of shame that the post British India, considers it a taboo, to talk and discuss it in the public. Like many other ancient scriptures and technologies that were all initiated by India, but are now used and further developed by the western world, India, in this case too only boasts itself of having just invented this, but, with little implications in their modern life. Like the Vedas, Upansihadas, Ayurveda, Yoga, Mathematics, Kamasutra or the science of sex, had also developed in this part of the world first, but, is considered obscene in present day India. What is even more insane is that there are numerous, monuments, buildings of the ancient and medieval history still present in this country, which openly depicts sex in the form of sculptures and paintings, and are popular tourist destinations, but watching the same over electronic media has been labelled illicit. [ABSTRACT FROM AUTHOR]

A monomeric complex of Cu(ii) with tinidazole [Cu(tnz)2Cl2] was synthesized. The complex decreases the formation of the nitro-radical anion (NO2Ṗ−), which was followed by an enzyme assay involving xanthine oxidase, a model nitro-reductase. It has a binding constant value with DNA comparable to that of tinidazole. In addition to the drug efficacy of the nitro radical anion, it also has neurotoxic side effects; so it is essential to control its formation to an optimum, sufficient for bringing about cytotoxic activity on disease causing microbes but avoiding excess that could make it neurotoxic. If this is achieved through modification of the 5-nitroimidazole moiety then too much NO2Ṗ− would not be generated, implying that the chances of the drug causing any harm to the host due to toxic side effects could be reduced. However, with decreased NO2Ṗ− formation, in an effort to decrease complications, a certain amount of therapeutic efficacy would be compromised. Therefore, the biological activity of tinidazole and its modified form, a monomeric complex, was investigated to see how the latter compares with tinidazole under comparable conditions. Studies revealed that, in spite of decreased NO2Ṗ− formation, the complex showed similar activity to that of tinidazole on two bacterial strains and an amoeba strain, implying that it has other attributes, not known for 5-nitroimidazoles, that enable it to match the efficacy of tinidazole. The study suggests that there is a substantial decrease in NO2Ṗ− due to the formation of the tinidazole complex, meaning that the toxic side effects are likely to be reduced which is an advantage as it would improve the therapeutic index. [ABSTRACT FROM AUTHOR]

Introduction: Reported incidence of acute cor pulmonale (ACP) in patients with acute respiratory distress syndrome (ARDS) varies from 10% to 84%, despite being subjected to lung protective ventilation according to the current guidelines. The objective of this review is to find pooled cumulative incidence of ACP in patients with ARDS undergoing lung protective ventilation. Materials and Methods: We searched MEDLINE, EMBASE, Cochrane Library, KoreaMed, LILACS, and WHO Clinical Trial Registry. Cross-sectional or cohort studies were included if they reported or provided data that could be used to calculate the incidence proportion of ACP. Inverse variance heterogeneity (IVhet) and random effect model were used for the main outcome and measures. Results: We included 16 studies encompassing 1661 patients. The cumulative incidence of ACP using IVhet analysis was 23% (95% confidence interval [CI] = 18%-28%) over 3 days of lung protective ventilation. Random effect analysis of 7 studies (1250 patients) revealed pooled odd ratio of mortality of 1.16 (95% CI = 0.80-1.67, P = 0.44) due to ACP. Conclusion: Patients with ARDS have a 23% risk of developing ACP with lung protective ventilation. Findings of this review indicate the need of updating existing guidelines for ventilating ARDS patients to incorporate right ventricle protective strategy. PROSPERO registration number: CRD42017054688. [ABSTRACT FROM AUTHOR]

Variation of pyridyl based receptors around a Cu(ii) center results in structural diversity allowing redox triggered Cu(ii)/Cu(i) fluorescence switch for intracellular Cu(i) imaging. Single crystal X-ray structures of 2-hydroxy-6-methylnicotinic acid (L1), its mono nuclear Cu(ii) complex, viz. [Cu(L1)2(H2O)(SO4)]·2H2O (C1a), polymeric Cu(ii) complex (C1b) and a dinuclear Cu(ii) complex of 2-(naphthalen-2-ylmethylsulfanyl)-nicotinic acid (L4), viz. [Cu2(L4)4(H2O)2]·1.12H2O (C4) with a Cu–Cu distance of 2.6028(7) Å are reported. Moreover, C1a interacts with calf thymus DNA, which is useful for disruption of normal DNA activity with plausible applications in biology (binding constant, K′ = 1.56 × 104). Chemical or electrochemical reduction of C1a generates a fluorescent Cu(i) complex. The lowest detection limit of L1 for Cu(i) is 50 μM. The association constant of L1 for Cu+ is 7.09 × 102. Quenching constants of Cu(ii) for L1, L2, L3 and L4 are 4 × 105, 4.2 × 106, 8.9 × 105 and 4.4 × 106, respectively. The magnetic behavior of C1b indicates a ferromagnetic one-dimensional solid. [ABSTRACT FROM AUTHOR]

The active fraction and/or compounds of Calendula officinalis responsible for wound healing are not known yet. In this work we studied the molecular target of C. officinalis hydroethanol extract (CEE) and its active fraction (water fraction of hydroethanol extract, WCEE) on primary human dermal fibroblasts (HDF). In vivo, CEE or WCEE were topically applied on excisional wounds of BALB/c mice and the rate of wound contraction and immunohistological studies were carried out. We found that CEE and only its WCEE significantly stimulated the proliferation as well as the migration of HDF cells. Also they up-regulate the expression of connective tissue growth factor (CTGF) and α-smooth muscle actin (α-SMA) in vitro. In vivo, CEE or WCEE treated mice groups showed faster wound healing and increased expression of CTGF and α-SMA compared to placebo control group. The increased expression of both the proteins during granulation phase of wound repair demonstrated the potential role of C. officinalis in wound healing. In addition, HPLC-ESI MS analysis of the active water fraction revealed the presence of two major compounds, rutin and quercetin-3-O-glucoside. Thus, our results showed that C. officinalis potentiated wound healing by stimulating the expression of CTGF and α-SMA and further we identified active compounds. Copyright © 2016 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Electrochemical behavior of the Ni complex of sodium 1,4-dihydroxy-9,10-anthraquinone-2-sulfonate Na[Ni(LHSO)Cl] · 2HO was studied by cyclic voltammetry in non-aqueous and aqueous buffer. The aim of the present work was to understand the behavior of the semiquinone radical anion formed after reduction of the free quinone centre of a ligand for which the other quinone centre binds a metal ion (Ni), not having a stable low oxidation state. In dimethylformamide solution an additional reduction peak appeared at a much more negative potential due to adsorption. The complex Na[Ni(LHSO)Cl] · 2HO undergoes diffusion controlled one-electron reduction unlike the two-electron reduction observed for most hydroxy-9,10-anthraquinones inspite of having two quinone centres in the complex (one on each ligand). In aqueous media a kinetic effect was observed during electron transfer at the electrode surface. The values of the electron transfer rate constants during the reduction of the complex at the electrode were evaluated and found to be dependent on the scan rate. Electrochemical behavior of the chosen hydroxy-9,10-anthraquinone (NaLHSO) was significantly modified in the complex with quinone. This result is important for biochemical studies, since NaLHSO resembles the core moiety of anthracycline antitumor drugs. Several studies have reported that in case of anthracyclines complexation can help to reduce the formation of semiquinone moieties, leading to a lesser generation of superoxide responsible for drug's cardiotoxicity. The electrochemical behavior of the title complex actually justifies such claims and tries to explain why a reduction in semiquinone formation helps to decrease the formation of superoxide. [ABSTRACT FROM AUTHOR]

Mussel adhesion to mineral surfaces is widely attributed to 3,4-dihydroxyphenylalanine (Dopa) functionalities in the mussel foot proteins (mfps). Several mfps, however, show a broad range (30%-100%) of tyrosine (Tyr) to Dopa conversion suggesting that Dopa is not the only desirable outcome for adhesion. Here, a partial recombinant construct of mussel foot protein-1 (rmfp-1) and short decapeptide dimers with and without Dopa are used and both their cohesive and adhesive properties on mica are assessed using a surface forces apparatus. Our results demonstrate that at low pH, both the unmodified and Dopa-containing rmfp-1s show similar energies for adhesion to mica and self-self-interaction. Cohesion between two Dopa-containing rmfp-1 surfaces can be doubled by Fe3+ chelation, but remains unchanged with unmodified rmfp-1. At the same low pH, the Dopa-modified short decapeptide dimer did not show any change in cohesive interactions even with Fe3+. The results suggest that the most probable intermolecular interactions are those arising from electrostatic (i.e., cation-π) and hydrophobic interactions. It is also shown that Dopa in a peptide sequence does not by itself mediate Fe3+ bridging interactions between peptide films: peptide length is a crucial enabling factor. [ABSTRACT FROM AUTHOR]

Background and Aims: Postsurgical pain is the leading complaint after laparoscopic cholecystectomy that may delay the postoperative recovery and hence we undertook a prospective randomized trial to analyze the role of flupirtine as a preemptive analgesic for postoperative pain relief in patients undergoing above surgery. Material and Methods: A total of 66 cases were randomly assigned to two groups to receive capsule flupirtine (200 mg) or capsule vitamin B complex administered orally, 2 h before the laparoscopic cholecystectomy surgery. Time to first analgesic requirement, assessment of postoperative pain in terms of visual analog score, and analgesic requirement postoperatively were measured as a primary outcome. Results: Time to first analgesic requirement was significantly prolonged in the flupirtine group as compared with the placebo group. There was significant pain reduction in early postoperative period (up to 4 h), but no changes occurred thereafter. Total analgesic requirement (including rescue analgesia) and side-effects were comparable between the groups except for higher sedation in flupirtine group. Conclusions: Flupirtine is effective as a preemptive analgesic in providing adequate pain relief during the immediate postoperative period after laparoscopic cholecystectomy surgery. However, continuation of drug therapy postoperatively could possibly delineate its optimal analgesic profile more profoundly. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Anaesthesia / Journal Canadien d'Anesthésie is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A 1 : 2 copperII complex of 1-amino-4-hydroxy-9,10-anthraquinone (QH) having the molecular formula CuQ2 was prepared and characterized by elemental analysis, NMR, FTIR, UV-vis and mass spectroscopy. The powder diffraction of the solid complex, magnetic susceptibility and ESR spectra were also recorded. The presence of the planar anthraquinone moiety in the complex makes it extremely difficult to obtain a single crystal suitable for X-ray diffraction studies. To overcome this problem, density functional theory (DFT) was used to evaluate an optimized structure of CuQ2. In the optimized structure, it was found that there is a tilt of the two planar aromatic anthraquinone rings of the complex with respect to each other in the two planes containing the O–Cu(ii)–O plane. The present study is an important addition to the understanding of the structural aspects of metal-anthracyclines because there are only a few reports on the actual structures of metal-anthracyclines. The theoretical vibrational spectrum of the complex was assigned with the help of vibrational energy distribution analysis (VEDA) using potential energy distribution (PED) and compared with experimental results. Being important in producing the biochemical action of this class of molecules, the electrochemical behavior of the complex was studied in aqueous and non-aqueous solvents to find certain electrochemical parameters. In aqueous media, reduction involves a kinetic effect during electron transfer at an electrode surface, which was characterized very carefully using cyclic voltammetry. Electrochemical studies showed a significant modification in the electrochemical properties of 1-amino-4-hydroxy-9,10-anthraquinone (QH) when bound to CuII in the complex compared to those observed for free QH. This suggests that the copper complex might be a good choice as a biologically active molecule, which was reflected in the lack of stimulated superoxide generation by the complex. [ABSTRACT FROM AUTHOR]

Mussel (Mytilus californianus) adhesion to marine surfaces involves an intricate and adaptive synergy of molecules and spatio-temporal processes. Although the molecules, such as mussel foot proteins (mfps), are well characterized, deposition details remain vague and speculative. Developing methods for the precise surveillance of conditions that apply during mfp deposition would aid both in understanding mussel adhesion and translating this adhesion into useful technologies. To probe the interfacial pH at which mussels buffer the local environment during mfp deposition, a lipid bilayer with tethered pH-sensitive fluorochromes was assembled on mica. The interfacial pH during foot contact with modified mica ranged from 2.2 to 3.3, which is well below the seawater pH of ~ 8. The acidic pH serves multiple functions: it limits mfp-Dopa oxidation, thereby enabling the catecholic functionalities to adsorb to surface oxides by H-bonding and metal ion coordination, and provides a solubility switch for mfps, most of which aggregate at pH ≥ 7–8. [ABSTRACT FROM AUTHOR]

An acetate-bridged binuclear Cu(II) complex of the antiparasitic drug ornidazole was synthesized and characterized by different techniques. Single crystal X-ray diffraction revealed that the complex had a paddle wheel structure. Enzymatic assay experiments performed under anaerobic conditions on ornidazole and its Cu(II)-complex using xanthine oxidase as a model nitro-reductase showed that complex formation is able to cause a significant decrease in the reduction of the nitro group on the imidazole ring. Reduction products of 5-nitroimidazoles interact with DNA, causing destruction of the double helical structure and strands, leading to the inhibition of protein synthesis. Although not directly coordinated to the metal center, such a decrease in the generation of nitro radical anion through complex formation would result in decreased cytotoxicity of the complex, which could be a disadvantage from the standpoint of drug efficacy. For this reason, other aspects associated with the drug action of 5-nitroimidazoles, such as DNA binding, were studied. Experiments using cyclic voltammetry revealed that the binding of the complex was almost comparable to ornidazole. Bactericidal activity of ornidazole and the complex was studied on two separate bacterial strains, showing that the complex was comparable to ornidazole. Nitro radical anions are known to adversely affect the central nervous system, and this study showed that the Cu(II) complex has the ability to decrease the generation of NO2Ṗ− to an extent that struck the correct balance for beneficial activity, as cytotoxicity due to ornidazole was not affected. [ABSTRACT FROM AUTHOR]