A new series of alkaline earthides based on Cryptand 2.2.2 (C222) containing nine complexes is designed by carefully placing alkali metals and alkaline earth metals inside and outside the C222 ...complexant, respectively i.e., M1(C222)M2 (M1 = Li, Na, K; M2 = Be, Mg, Ca). The designed complexes are reasonably stable both electronically and thermodynamically, as revealed through their vertical ionization potentials (VIPs) and interaction energies, respectively. Moreover, the true alkaline earthide nature of the complexes is confirmed through NBO and FMO analyses showing the negative charges and HOMOs over the alkaline earth metals, respectively. The further validity of true earthide characteristic is represented graphically by the spectra of partial density of states (PDOS). HOMO-LUMO gaps of the compounds are also very small (from 2.23 to 2.83 eV) when compared with pure cage's (C222) H-L gap i.e., 5.63 eV. All these features award these complexes with very small values of transition energies (ΔE) ranging from 0.68 to 2.06 eV ultimately resulting in remarkably high hyperpolarizability values up to 2.7 × 105 au (for Na+(C222)Mg−). Furthermore, applying external electric field (EEF) on the complexes enhances hyperpolarizability further. A remarkable increase of 1000 folds has been seen when hyperpolarizability of K+(C222)Ca− is calculated after EEF application i.e., from 8.79 × 104 au to 2.48 × 107 au; when subjected to 0.001 au external electric field.
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•CTF-0 covalent organic framework is studied as drug delivery system for anticancer drugs.•The adsorption energy is higher for FU (−17.45 kcal/mol) as compared to NU ...(−14.83 kcal/mol).•The highest change in dipole moment of FU after adsorption indicates its high hydrophilicity.•CTF-0 can be suitable carrier for the drug delivery of FU.
2D sheet like materials such graphene are superior drug delivery systems compared to the conventional macro systems due to good adsorption and reasonable bioavailability. The adsorption and bioavailability can be further improved with periodic cavity containing 2D materials which can bind with drug molecules with moderate binding energies. Therefore, we have studied for the first time the potential of 2-dimensional porous covalent triazine framework (CTF-0) for the delivery of anticancer drugs fluorouracil (FU) and nitrosourea (NU). Adsorption energy analysis shows that the drug molecules bind with CTF-0 with moderate interaction energies which is prime requirement of a good drug delivery system. However, FU@CTF-0 complex (−17.45 kcal/mol) is more stable than NU@CTF-0 (−14.83 kcal/mol), and that the dipole moment of surface increases after adsorption of drugs. The increase in dipole moment after complex formation helps to improve the solubility, which is necessary for drug delivery in biological systems. Symmetry adapted perturbation theory confirms the stability of drug-loaded complexes, where the contribution from dispersion interactions is the highest. The HOMO-LUMO energy gap (EH-L) of CTF-0 decreases from 4.5 eV to 4.1 eV and 4.0 eV after loading of FU and NU respectively. The pH in cancerous tissues is typically low, which can lead to protonation of a drug and hence aid its delivery to target cells. The nature of the attraction between the CTF-0 surface and different drugs has been evaluated on the bases of noncovalent interactions (NCI) and also the quantum theory of atoms in molecules (QTAIM). QTAIM results confirm that FU has a stronger affinity towards CTF-0 than NU. Based on all our calculated results, CTF-0 appears to be a viable candidate for the delivery of the anticancer drug FU. Previously reported surface for FU and NU drugs has much higher interaction energy which is problematic for the release of drug from the carrier in the biological system. This study provides useful information that may assist the experimental formulation of a CTF-0-based DDS for FU.
•Calix4pyrrole complexant based alkaline earthides have been designed.•Alkali metals act as source of electrons for alkaline earth metal atoms.•In alkaline earthide, the nature of compounds is ...confirmed by NBO and FMO analysis.•Alkaline earthides’ NLO response increases by two orders of magnitude in the presence of external electric field.
We report here rationally designed alkaline earthides using calix4pyrrole complexant. Alkali metal atoms are intercalated into calix4pyrrole while alkaline earth metals are kept outside the cavity to form M+(calix4pyrrole)M- (M+ = Li, Na & K; M- = Be, Mg & Ca). Under the action of four N atoms, the s valence electron of the alkali metal atoms overflows from the bottom of the cup to becomes excess electrons and enwraps the alkaline earth metal forming negative charge on alkaline earth metal. Nine complexes with general formula, M+(calix4pyrrole)M- (M+ = Li, Na and K; M- = Be, Mg and Ca) are designed and their geometric, electronic and nonlinear optical (NLO) properties are studied in detail. The alkaline earthide identities of the designed compounds are determined by distribution of electron densities in highest occupied molecular orbitals (HOMOs) and natural bond orbital (NBO) analyses. Presence of negative charges and localization of HOMOs on alkaline earth metals in all these complexes shows the alkaline earthide nature of these complexes. The spectra of partial density of states (PDOS) further confirm the presence of excess electrons on alkaline earth metals. These alkaline earthides show considerably high nonlinear optical responses with the first hyperpolarizabilities (βo) up to 1.98x104 au. Such high βo values are attributed to the presence of excess electron on alkaline earth metals. Moreover, their low transition energies from 2.06 to 3.87 eV reveal the susceptible and diffuse nature of excess electron. We also calculated the NLO response of designed complexes under the influence of external electric field of strength 0.001 a.u and found that NLO response of Li+Calix4pyrroleCa- has increased from 1.90 × 104 a.u to 8.19 x106 a.u. We expect that our work may inspire experimental chemists to explore synthetic, chemical and physical characterization of these new alkaline earthides.
Salinity is among the major abiotic stresses negatively affecting the growth and productivity of crop plants. Sodium nitroprusside (SNP) -an external nitric oxide (NO) donor- has been found effective ...to impart salinity tolerance to plants. Soybean (Glycine max L.) is widely cultivated around the world; however, salinity stress hampers its growth and productivity. Therefore, the current study evaluated the role of SNP in improving morphological, physiological and biochemical attributes of soybean under salinity stress. Data relating to biomass, chlorophyll and malondialdehyde (MDA) contents, activities of various antioxidant enzymes, ion content and ultrastructural analysis were collected. The SNP application ameliorated the negative effects of salinity stress to significant extent by regulating antioxidant mechanism. Root and shoot length, fresh and dry weight, chlorophyll contents, activities of various antioxidant enzymes, i.e., catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate peroxidase (APX) were improved with SNP application under salinity stress compared to control treatment. Similarly, plants treated with SNP observed less damage to cell organelles of roots and leaves under salinity stress. The results revealed pivotal functions of SNP in salinity tolerance of soybean, including cell wall repair, sequestration of sodium ion in the vacuole and maintenance of normal chloroplasts with no swelling of thylakoids. Minor distortions of cell membrane and large number of starch grains indicates an increase in the photosynthetic activity. Therefore, SNP can be used as a regulator to improve the salinity tolerance of soybean in salt affected soils.
Innovation in UAV design technologies over the last decade and a half has resulted in capabilities that flourished the development of unique and complex multi-mission capable UAVs. These emerging new ...distinctive designs of UAVs necessitate development of intelligent and robust Control Laws which are independent of inherent plant variations besides being adaptive to environmental changes for achieving desired design objectives. Current research focuses on development of a control framework which aims to maximize the glide range for an experimental UAV employing reinforcement learning (RL)-based intelligent control architecture. A distinct model-free RL technique, abbreviated as ‘MRL’, is suggested which is capable of handling UAV control complications while keeping the computation cost low. At core, the basic RL DP algorithm has been sensibly modified to cater for the continuous state and control space domains associated with the current problem. Review of the performance characteristics through analysis of the results indicates the prowess of the presented algorithm to dynamically adapt to the changing environment, thereby making it suitable for complex designed UAV applications. Nonlinear simulations carried out under varying environmental conditions illustrated the effectiveness of the proposed methodology and its success over the conventional classical approaches.
We aim to investigate the impact of corporate governance attributes on future stock price crash risk in stable and crisis periods. We used Dynamic Panel Generalized Method of Movements (DPGMM) and ...Principal Component Analysis (PCA) to generate the factors for the individual attribute to capture the accuracy of the results. Ownership concentration and board structure have a significant negative while audit quality has no association with the stock price crash risk. However, the financial crisis has a positive association with stock crash risk. Furthermore, the study provides a potential screening methodology for investors to mitigate future risk as to price crash risk for portfolios that cannot be dealt with diversification.
Design complexities of trending UAVs and the operational harsh environments necessitates
Control Law
formulation utilizing intelligent techniques that are both robust, model-free and adaptable. In ...this research, an intelligent control architecture for an experimental Unmanned Aerial Vehicle (UAV) having an unconventional inverted V-tail design, is presented. Due to unique design of the vehicle strong roll and yaw coupling exists, making the control of vehicle challenging. To handle UAV’s inherent control complexities, while keeping them computationally acceptable, a variant of distinct Deep Reinforcement learning (DRL) algorithm, namely Reformed Deep Deterministic Policy Gradient (R-DDPG) is proposed. Conventional DDPG algorithm after being modified in its learning architecture becomes capable of intelligently handling the continuous state and control space domains besides controlling the platform in its entire flight regime. The paper illustrates the application of modified DDPG algorithm (namely R-DDPG) towards the design, while the performance of the resulting controller is assessed in simulation using dynamic model of the vehicle. Nonlinear simulations were then performed to analyze UAV performance under different environmental and launch conditions. The effectiveness of the proposed strategy is further demonstrated by comparing the results with the linear controller for the same UAV whose feedback loop gains are optimized by employing technique of optimal control theory achieved through application of Linear quadratic regulator (LQR) based control strategy. The efficacy of the results and performance characteristics, demonstrated the ability of the presented algorithm to dynamically adapt to the changing environment, thereby making it suitable for UAV applications.
In this research, an intelligent control architecture for an experimental Unmanned Aerial Vehicle (UAV) bearing unconventional inverted V-tail design, is presented. To handle UAV’s inherent control ...complexities, while keeping them computationally acceptable, a variant of distinct Deep Reinforcement Learning (DRL) algorithm, namely Deep Deterministic Policy Gradient (DDPG) is proposed. Conventional DDPG algorithm after being modified in its learning architecture becomes capable of intelligently handling the continuous state and control space domains besides controlling the platform in its entire flight regime. Nonlinear simulations were then performed to analyze UAV performance under different environmental and launch conditions. The effectiveness of the proposed strategy is further demonstrated by comparing the results with the linear controller for the same UAV whose feedback loop gains are optimized by employing technique of optimal control theory. Results indicate the significance of the proposed control architecture and its inherent capability to adapt dynamically to the changing environment, thereby making it of significant utility to airborne UAV applications.
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Background: Ascites is a shared pathological manifestation of numerous diseases, the primary (81%) disease being hepatic cirrhosis. Ascites is termed “malignant” when it is ...associated with cancers. It can manifest as abdominal swelling, abdominal pain, nausea and vomiting, anorexia and fatigue. Our study aimed at identifying baseline characteristic in patients who present to our hospital with malignant ascites as the first sign of advanced stage cancers and the factors that can affect outcomes in such patients. Methods: This is a retrospective study which includes all the patients who had been diagnosed with malignant ascites at our institute between the years 2012 and 2016.The diagnosis was made either on the basis of cytological examination or medical imaging or both. Patients who were younger than 18 years and who developed ascites due to diseases other than malignancy were excluded from the study. A total of 150 patients were shortlisted using these criteria. Results: The mean age of the sample was 56.52 years with 101 (67%) of the patients being female, 54 (36%) diabetic, 55 (37%) hypertensive, 26 (52%) and 12 (8%) had ischemic heart disease. The most prevalent tumor reported was ovarian cancer 47 (31%) with the highest frequency of metastasis reported in the peritoneal region 34 (23%). Among symptoms, the most prevalent were abdominal distension 127 (85%), abdominal pain 99 (66%), 41 (27%) nausea, 44 (29%) vomiting and 32 (21%) reported weight change. Paracentesis was done in 139 (92%) for palliation of symptoms .Surgery was performed on 11 (7%) of the patients, whereas 70 (47%) of the patients were switched to chemotherapy with Carboplatin-Taxol constituting the major chemotherapeutic regimen. Majority 93 (62%) of the patients were discharged in a stable condition. The median survival following diagnosis of ascites was three months. Ovarian cancer favored longer survival while low serum albumin, low serum protein and liver metastases adversely affected survival. The independent prognostic factors for survival were cancer type, liver metastases and serum albumin. Conclusions: The identified independent prognostic factors should be used to select patients for multimodality therapy for adequate palliation.
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