COVID-19, a blessing in disguise for the Tech sector: Evidence from stock price crash risk

In this paper we document that although COVID-19 has brought uncertainties to the overall economy, the Technology (tech) sector is the systematic beneficiary of the pandemic. Using a quasi-natural setup, we find a significant notion that the Stock Price Crash Risk (SPCR) of firms within the Tech sector decreases during the COVID-19 pandemic compared to the recent past and firms belonging to other sectors. Our analyses further reveal that firms in the Tech sector with stronger external monitoring and better information environment receive an even greater advantage from the pandemic. Overall, our study suggests that the higher systemic dependency on the Tech sector during the COVID-19 outbreak results in an economic benefit for this sector.

Diagnostic Value of Clinical Profile and Proposed a Clinical Diagnostic Criterion of Enteric Fever

Enteric fever is a common bacterial infection in the tropics and endemic to Bangladesh. The volatile manifestations of enteric fever construct this disease a true diagnostic confrontation. There are limited current objective data on the value of individual clinical features of enteric fever in the diagnosis of enteric fever. The aim of the study was analysis of clinical features and also proposed a clinical diagnostic criterion of enteric fever among adult in Bangladesh. This cross-sectional comparative study was performed among which of fifty confirmed enteric fever and hundred non enteric febrile adult patients in Bangabandhu Sheikh Mujib Medical University, Dhaka, Bangladesh from January 2015 to December 2015. Purposive sampling technique was implied for convenience of the study. In this study, history of step ladder fever, diarrhoea and relative bradycardia, ceacal gurgle, abdominal distension were proved to be powerful markers of enteric fever with high specificity (100.0%, 90.0%, 95.0%, 92.0% and 95.0% respectively). Tender right iliac fossa (RIF) and coated tongue, hepatomegaly were moderately powerful with 86.0%, 88.0%, 89.0% specificity respectively. Positive predictive value (PPV) was highest for step ladder fever (100%) and negative predictive value (NPV) was highest for headache (92.5%). Highest sensitivity, PPV and NPV were found for relative bradycardia and tender RIF but most of the signs had good specificity. Regarding accuracy it was highest for step ladder fever (91.3%), relative bradycardia (94%), tender RIF (87%), coated tongue (82%) and splenomegaly (84%). Therefore, a clinical diagnostic criterion was submitted with diagnostic accuracy more than 70% were taken into deliberation. The Major criteria were considered step ladder fever, relative bradycardia, tender RIF with diagnostic accuracy 91.0%, 94.0% and 87.0% respectively. Minor criteria included splenomegaly, diarrhoea, coated tongue, ceacal gurgle, chills with diagnostic accuracy 85.0%, 85.0%, 82.0%, 76.0%, 72.0% respectively and after amalgamation of various major and minor criteria a final diagnostic criterion was submitted having accuracy more than 60.0%. In conclusion the clinical profile of enteric fever in culture proven patients with a view to highlight the predictive value of those features which would help general practitioners in the diagnosis and empiric treatment.

Preparation and Optimization of PEGylated Nano Graphene Oxide-Based Delivery System for Drugs with Different Molecular Structures Using Design of Experiment (DoE)

Graphene oxide (GO), due to its 2D planar structure and favorable physical and chemical properties, has been used in different fields including drug delivery. This study aimed to investigate the impact of different process parameters on the average size of drug-loaded PEGylated nano graphene oxide (NGO-PEG) particles using design of experiment (DoE) and the loading of drugs with different molecular structures on an NGO-PEG-based delivery system. GO was prepared from graphite, processed using a sonication method, and functionalized using PEG 6000. Acetaminophen (AMP), diclofenac (DIC), and methotrexate (MTX) were loaded onto NGO-PEG particles. Drug-loaded NGO-PEG was then characterized using dynamic light scattering (DLS), Fourier transform infrared (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), XRD. The DLS data showed that the drug-loaded NGO-PEG suspensions were in the size range of 200 nm-1.3 µm. The sonication time and the stirring rate were found to be the major process parameters which affected the average size of the drug-loaded NGO-PEG. FTIR, DSC, XRD, and SEM demonstrated that the functionalization or coating of the NGO occurred through physical interaction using PEG 6000. Methotrexate (MTX), with the highest number of aromatic rings, showed the highest loading efficiency of 95.6% compared to drugs with fewer aromatic rings (diclofenac (DIC) 70.5% and acetaminophen (AMP) 65.5%). This study suggests that GO-based nano delivery systems can be used to deliver drugs with multiple aromatic rings with a low water solubility and targeted delivery (e.g., cancer).

Design and synthesis of a luminescent iridium complex-peptide hybrid (IPH) that detects cancer cells and induces their apoptosis

Tumor necrosis factor related apoptosis inducing ligand (TRAIL) triggers the cell-extrinsic apoptosis pathway by complexation with its signaling receptors such as death receptors (DR4 and DR5). TRAIL is a C₃-symmetric type II transmembrane protein, consists of three monomeric units. Cyclometalated iridium(III) complexes such as fac-Ir(tpy)₃ (tpy = 2-(4-tolyl)pyridine) also possess a C₃-symmetric structure and are known to have excellent luminescence properties. In this study, we report on the design and synthesis of a C₃-symmetric and luminescent Ir complex-peptide hybrid (IPH), which contains a cyclic peptide that had been reported to bind to death receptor (DR5). The results of MTT assay of Jurkat, K562 and Molt-4 cells with IPH and co-staining experiments with IPH and an anti-DR5 antibody indicate that IPH binds to DR5 and induces apoptosis in a manner parallel to the DR5 expression level. Mechanistic studies of cell death suggest that apoptosis and necrosis-like cell death are differentiated by the position of the hydrophilic part that connects Ir complex and the peptide units. These findings suggest that IPHs could be a promising tool for controlling apoptosis and necrosis by activation of the extra-and intracellular cell death pathway and to develop new anticancer drugs that detect cancer cells and induce their cell death.