Ultraviolet light induced annihilation of silicon dangling bonds in hydrogenated amorphous silicon nitride films

We report results of electron paramagnetic resonance, photothermal deflection spectroscopy, and capacitance‐voltage measurements on amorphous hydrogenated silicon nitride (a‐SiNx:H) thin films exposed to ultraviolet (UV) illumination. It has been previously shown that exposure to UV light activates silicon dangling‐bond defects, i.e., K0 centers, in a‐SiNx:H thin films. Here, we demonstrate that the initially UV‐activated K0 center can be irreversibly annihilated at long illumination times. Because this effect seems to scale with H content of the measured films, we propose that hydrogen may be passivating the K0 defects during the extended UV exposure. We also show that films subjected to long UV exposures trap charge as efficiently as those having much larger K0 concentrations. A few possibilities to explain this effect are discussed. © 1995 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70316/2/JAPIAU-77-11-5730-1.pd

Newly discovered rock art sites in Balandar, Mashhad province, north-eastern Iran

The site of Pire Mazar Balandar (or PMB001) is located near the village of Balandar in the Khorasan region of north-eastern Iran (33 degrees 0937.64N, 59 degrees 2952E; Figure 1). It consists of an outcrop of volcanic rock on a mountain peak (1532m asl) on the north-eastern side of the Binaloud range, above the city of Mashhad (Figure 2)

Gastrointestinal cancers, ACE-2/TMPRSS2 expression and susceptibility to COVID-19

Recent studies on the pathophysiology of COVID-19 are indicating that the Angiotensin convertase enzyme 2 (ACE-2) and transmembrane serine protease 2 (TMPRSS2) can act as a major component in the fusion of SARS-Cov-2 with target cells. It has also been observed that the expression of ACE-2 and TMPRSS2 can be altered in malignancies. Shedding light on this matter could be crucial since the COVID-19 pandemic interfered with many gastrointestinal cancer screening programs. Herein we discuss the possibility of severe forms of COVID-19 in patients with gastrointestinal cancers due to the gastrointestinal entry route of SARS-CoV-2 into the human body. The disruption of cancer screening programs caused by the current COVID-19 pandemic could therefore have massive negative health impact on patients affected by gastrointestinal malignancies

DFT assessments of BN, AlN, and GaN decorated carbon cage scaffolds for sensing the thiamazole drug

Sensing drug substances by nanostructures are very important in accordance with the management of targeted drug delivery processes and drug substances detections. Boron nitride (BN), aluminum nitride (AlN), and gallium nitride (GaN) decorated carbon cage (BN-C, AlN-C, and GaN-C) scaffolds were assessed towards sensing the thiamazole (TMZ) drug through the wB97XD/6–31 + G* level of density functional theory (DFT) computations. The singular models were optimized and their combinations to each other were stabilized to obtain the interacting TMZ@Scaffold bimolecular complexes and their corresponding features. The results indicated the existence of non-covalent physical interactions between the substances and their electronic features indicated possibility of sensing function for the investigated scaffolds. Based on the variations of values of adsorption energy and energy gap, the features of recovery time and conductance rate were achieved to predict a sensing function for the models; TMZ@GaN-C was found at the highest suitability in comparison with TMZ@AlN-C and TMZ@BN-C models. The obtained thermochemistry results indicated a spontaneous process for the formation of TMZ@Scaffold complexes. Based on all the obtained results, an order of TMZ@GaN-C > TMZ@AlN-C > TMZ@BN-C was found for describing stability, formation, and electronic features suitability by assigning specific features for each of the singular BN-C, AlN-C, and GaN-C scaffolds towards the TMZ drug. As a consequence, two purposes of detections and adsorptions were approached for the investigated scaffolds to develop sensing functions of BN-C, AlN-C, and GaN-C scaffolds for the TMZ drug