Macroeconomic and Microeconomic Determinants of Efficiency of Indian Construction & Engineering Firms: An Investigation

In an intensely competitive business world, it is of great importance that the firms must perform efficiently for long-term sustainability. The present study made a modest effort to shed some light on the efficiency of the select 47 construction and engineering firms and the different microeconomic and macroeconomic factors affecting such efficiency during the period 1999-2000 to 2018-2019. For the purpose of this study, Stochastic Frontier Analysis was used primarily to determine the firm-level efficiency scores. Subsequently, the determinants of such firm-level efficiency were looked into using Panel Censored Tobit Regression Model. The results of the study showed that leverage, size, age, openness, exchange rate and price factor were the important determinants of the efficiency of the construction and engineering firms during the period of study

Vitamin D toxicity

A 67-year-old female was admitted to the hospital with a history of lethargy, memory impairment, confusion, anorexia and gait imbalance for 2 weeks duration. She did not have any history of fall or head injury. She had total hip replacement 1 year back and was on orthopedic follow-up. Magnetic resonance imaging (MRI) on admission revealed no focal abnormalities. Routine biochemistry detected hypercalcemia, and she was treated with I/V fluid, diuretics and glucocorticoids. She was screened thoroughly to exclude occult malignancy. After 7 days of admission, a follow-up orthopedic prescription revealed that she was getting inj. Arachitol 6 lac units every week for last 3 months. On the 9th day of admission, she was detected to have very high serum 25(OH) vitamin D level (254.70 ng/ml). Patient was discharged after 2 weeks after her serum calcium came down to normal range with the advice of no dietary calcium and vitamin D intake. Her 25(OH) vitamin D level remained high for the next 6 months. Now she is completely asymptomatic and her serum 25(OH) D is normal

1-(2-Aminophenyl)-3H-[1,2,3] triazole-4-carboxylic acid: activity against Gram-positive and Gram-negative pathogens including Vibrio Cholerae

Figures ESI S1, S2, S3; synthesis scheme and characterization of compounds, 1H NMR, 13C NMR and Mass spectrum : Figure S1-S11

Safety of statins

Statins are an established class of drugs with proven efficacy in cardiovascular risk reduction. The concern over statin safety was first raised with the revelation of myopathy and rhabdomyolysis with the use of now withdrawn cerivastatin. Enhanced understanding of the mechanisms behind adverse effects of statins including an insight into the pharmacokinetic properties have minimised fear of statin use among clinicians. Studies reveal that occurrence of myopathy and rhabdomyolysis are rare 1/100000 patient-years. The risk of myopathy/rhabdomyolysis varies between statins due to varying pharmacokinetic profiles. This explains the differing abilities of statins to adverse effects and drug interaction potentials that precipitate adverse effects. Higher dose of rosuvastatin (80 mg/day) was associated with proteinuria and hematuria while lower doses were devoid of such effects. Awareness of drugs interacting with statins and knowledge of certain combinations such as statin and fibrates together with monitoring of altered creatine kinase activity may greatly minimise associated adverse effects. Statins also asymptomatically raise levels of hepatic transaminases but are not correlated with hepatotoxicity. Statins are safe and well tolerated including more recent potent statins such as, rosuvastatin. The benefits of intensive statin use in cardiovascular risk reduction greatly outweigh risks. The present review discusses underlying causes of statin-associated adverse effects including management in high risk groups

Highly selective metallogel from 4-biphenylcarboxy capped diphenylalanine and FeCl3

The gelation property of the iron(iii) complex of 4-biphenylcarboxy capped diphenylalanine (l-Phe-l-Phe, the hydrophobic core motif of Alzheimer's β-amyloid polypeptide) has been reported. Gelation was observed selectively for FeCl3 and 4-biphenylcarboxy capped diphenylalanine, whereas Cd, Cu, Zn, Cr, Ni, Hg, Mg, Mn, Pb, and Pd complexes were not able to form a metallogel. However, Boc and acetyl capped diphenylalanine have failed to form a metallogel. The storage modulus of the metallogel was approximately an order of magnitude larger than the loss modulus, which indicates the elastic nature of the gel and the physical crosslink. The metallogel exhibits an entangled fiber network which is stabilized by weak interactions such as coordination, hydrogen bonding and π-π interactions. The solid-state study shows that the acetyl protected diphenylalanine adopts an extended conformation and forms a supramolecular helix-like structure through multiple intermolecular hydrogen bonds. However, the 4-biphenylcarboxy protected diphenylalanine shows a supramolecular sheet-like structure through intermolecular hydrogen bonds and π-π stacking interactions between the biphenyl moieties. © 2019 The Royal Society of Chemistry.This work was financed by IISER-Kolkata. S. Sasmal and K. Maji acknowledge the IISER Kolkata, India for a senior research fellowship.Peer reviewe

Fibril-forming model synthetic peptides containing 3-aminophenylacetic acid

The FT-IR, 1H NMR, electrospray mass spectrometry studies of several dipeptides containing 3-APA (3-aminophenylacetic acid) and Aib/Val/Pro, revealed that all peptides share a common structural feature, an extended backbone conformation and they form the intermolecular hydrogen bonded supramolecular β-sheet structure in the solid state. The SEM images of all peptides exhibit amyloid-like fibrils, reminiscent of many neurodegenerative diseases like Alzheimer's, Prion-protein diseases

Self-Healing Hydrogel from a Dipeptide and HCl Sensing

Ordered self-assembly of small organic molecules may induce novel properties in a supramolecular arrangement and can act as advance functional materials. This paper discusses the development of a new stimuli-responsive dipeptide hydrogelator containing l-phenylalanine and α-aminoisobutyric acid (Aib). The dipeptide Boc-Phe-Aib-OH, on addition with three equivalent of sodium hydroxide and water, transformed into a robust hydrogel. The transparent hydrogel is self-healing in nature. The instant gelation is highly selective toward sodium hydroxide and does not need any sonication or heating–cooling cycle. The thixotropic nature of the gel has been confirmed by rheological step-strain experiments at room temperature. Moreover, in the oil–water mixture, the compound exhibits phase-selective gelation. When the gel cylinder is cut into pieces, it does not conduct electricity, but once self-healing occurs, it conducts electricity. The diffusion of rhodamine 6G through the hydrogel indicates the dynamic nature. The hydrogel is highly sensitive toward HCl, that is, in the presence of HCl vapor, the gel becomes deformed

First crystallographic signature of the highly ordered supramolecular helical assemblage from a tripeptide containing a non-coded amino acid

The model tripeptide Boc-Leu(1)-Aib(2)-Phe(3)-OMe 1 containing a non-coded amino acid residue (Aib: α-amino isobutyric acid) forms a supramolecular helical assemblage via non-covalent interactions in single crystals. The SEM image of the peptide 1 in the solid state shows the ribbon like fibrillar morphology, a characteristic feature of highly ordered aggregated fibrils like amyloid fibrils

Conformational heterogeneity of a turn mimetic pseudo-peptide: comparison of crystal state, solution and theoretically derived structures

Crystal structure analysis of the pseudo-peptide (tert-Butyl N-{2-[ N-(N, N'-dicyclohexyl-ureidocarbonylethyl)carbamoyl]-prop-2-yl}carbamate) exhibited presence of a 13-membered intramolecular hydrogen bonded structure involving Boc C═O and Urea NH group to form an α-turn mimic [Acta Crystallogr. C 56 (2000) 1120]. However, NMR studies of this compound in CDCl3 using DMSO solvent titration of amide NH groups have revealed that the pseudo-peptide lacks of unique conformational state in solution. We have therefore carried out ab initio quantum mechanical calculations at up to B3LYP/6-31G** using density function theory level to characterise relative stabilities of different possible conformations with distinctive hydrogen bonding patterns. Computational studies also reveal that a 13-atom hydrogen bonded turn, identical to the crystal state conformation and analogous to the α-turn (in proteins) is energetically most stable. The structures with 7-atom hydrogen bonded turn (γ-turn) and with bifurcated hydrogen bonds are, however, seen to have energies quite comparable to that of the α-turn mimetic. This indicates possibility of existence of multiple conformational states, corresponding to various turn structures (viz. α-turn mimetic, γ-turn, etc.) which may interconvert in NMR time scale