Synthesis, Characterization and Pharmacological Screening of Some Novel 2- substituted and 1(H)-substituted Benzimidazole Derivatives as potent Anti-cancer agents

The most of drugs containing Benzimidazole ring is a prominent structural motif found in numerous therapeutically active compounds. Benzimidazole and its synthetic analogues have been found to exhibit industrial, agricultural and biological application such as antitubercular, anti-inflammatory, analgesic, anticancer, anticoagulant, as well as good antifungal and anti microbial activity. Recent advances in technology considers microwave irradiation energy as the most efficient means of heating reactions for chemical transformations that can be accomplished in a minutes. Microwave irradiation assists organic synthesis (MAOS) not only helps in implementing green chemistry but also led to progress in organic synthesis. We report pharmacological screening of some novel 2 substituted and 1(h)-substituted Benzimidazole derivatives.

Calculation of radiation dose enhancement by gadolinium compounds for radiation therapy

In this study, we evaluate the features of dose enhancement with Gd contrast agent (Magnevist). Due to the increased relaxation time and high atomic number (z=64) Gd can be used in radiation therapy as a radiosensitizer. To perform a quantitative evaluation of the radiosensitization effect is determined a parameter called the dose enhancement factor - DEF. The DEF values were calculated based on the analysis of the mass absorption coefficients for gadolinium and biological tissue. An increase in DEF is observed when the radiation energy is higher than the K-shell ionization energy of Gd atoms. For the presence of 20315 ppm Gd contrast agent in biological tissue the dose enrichment factor is maximum DEF = 4.12 at photon irradiation energy 60 keV. Also, based on calculations for photon irradiation sources considered high degrees of dose enhancement occur for Am-241, Yb-196, and 100 kVp X-ray tube.

Crosslinking Multilayer Graphene by Gas Cluster Ion Bombardment

In this paper, we demonstrate a new, highly efficient method of crosslinking multilayer graphene, and create nanopores in it by its irradiation with low-energy argon cluster ions. Irradiation was performed by argon cluster ions with an acceleration energy E ≈ 30 keV, and total fluence of argon cluster ions ranging from 1 × 109 to 1 × 1014 ions/cm2. The results of the bombardment were observed by the direct examination of traces of argon-cluster penetration in multilayer graphene, using high-resolution transmission electron microscopy. Further image processing revealed an average pore diameter of approximately 3 nm, with the predominant size corresponding to 2 nm. We anticipate that a controlled cross-linking process in multilayer graphene can be achieved by appropriately varying irradiation energy, dose, and type of clusters. We believe that this method is very promising for modulating the properties of multilayer graphene, and opens new possibilities for creating three-dimensional nanomaterials.

A Phase-Field Study of Microstructure Evolution in Tungsten Polycrystalline under He/D Irradiation

Analyses in the present study focus on understanding the evolution of the tungsten microstructure under He/D irradiation. A fractal dimension analysis was utilized to characterize the structural pattern of the microstructure irradiated by both low (10–80 eV) and high (8–30 keV) irradiation energy. All examined W microstructures show a direct correlation between the fractal dimension and irradiation energy. Analyses establish an empirical relation expressing a change in the microstructure as a function of the irradiation energy based on the changes in the fractal dimension of the microstructures. The proposed relation was implemented in the phase-field model formulation with an account of the interfacial energy induced by the crystallographic mismatch between grains under irradiation. The current phase-field model captures the evolution of the void under irradiation, including nucleation and the growth of voids, and sink efficiency for vacancy annihilation in the vicinity of grain boundaries.

Effect of pulsed soft X-ray radiation on the surface topography of some metals

Effect of the pulsed soft X-ray fluxes (PSXF) on the surface topography of metals (Mg and Cu) has been investigated. Soft pulse X-ray irradiation (energy quanta of 0.1-1.0 keV) were carried out on a high-current MIG generator. The sample of magnesium was located at a distance of 10 cm from the X-ray source. Since the distance to the sample significantly exceeded the size of the X-ray beam, it can be assumed that the density of the X-ray radiation flow to the magnesium sample was uniform. The duration of the radiation pulse was 100 ns, and the radiation energy density in the pulse varied from 13 to 19 J/cm2. As a result of melting under the action of PSXF of the near-surface layer of metals and subsequent solidification, a wavy relief is formed on their surface. Defects in the form of craters, which usually occur after the impact of a powerful pulsed ion flow on metals, were not detected.

The virucidal effects of 405 nm visible light on SARS-CoV-2 and influenza A virus

The germicidal potential of specific wavelengths within the electromagnetic spectrum is an area of growing interest. While ultra-violet (UV) based technologies have shown satisfactory virucidal potential, the photo-toxicity in humans coupled with UV associated polymer degradation limit their use in occupied spaces. Alternatively, longer wavelengths with less irradiation energy such as visible light (405 nm) have largely been explored in the context of bactericidal and fungicidal applications. Such studies indicated that 405 nm mediated inactivation is caused by the absorbance of porphyrins within the organism creating reactive oxygen species which result in free radical damage to its DNA and disruption of cellular functions. The virucidal potential of visible-light based technologies has been largely unexplored and speculated to be ineffective given the lack of porphyrins in viruses. The current study demonstrated increased susceptibility of lipid-enveloped respiratory pathogens of importance such as SARS-CoV-2 (causative agent of COVID-19) and influenza A virus to 405 nm, visible light in the absence of exogenous photosensitizers thereby indicating a potential alternative porphyrin-independent mechanism of visible light mediated viral inactivation. These results were obtained using less than expected irradiance levels which are considered safe for humans and commercially achievable. Our results support further exploration of the use of visible light technology for the application of continuous decontamination in occupied areas within hospitals and/or infectious disease laboratories, specifically for the inactivation of respiratory pathogens such as SARS-CoV-2 and Influenza A.

Enhancement of sunlight irradiation for wastewater disinfection by mixing with seawater

There is a need for developing a simple and easy-to-maintain disinfection technique for sewage treatment for use in developing countries and disaster-affected areas. We propose a novel disinfection technology that inactivates bacteria in wastewater via sunlight irradiation under high salt concentration by mixing with seawater. The disinfection efficiency of the proposed method was quantitatively evaluated and examined using fecal indicator bacteria. When the salinity in wastewater was adjusted to 30 practical salinity units by mixing with seawater, the constant of inactivation irradiation energy Ks (m2/MJ) was 1.6–2.2-fold greater than that without seawater for total coliforms and Escherichia coli. By contrast, although enterococci were inactivated by sunlight irradiation, an increase in salinity did not enhance disinfection. On setting the irradiation energy of sunlight to 5.5 MJ/m2, >99% of the fecal indicator bacteria were inactivated. Finally, we examined the relationship between the attenuation of irradiance and water depth and accordingly proposed a design of a treatment system wherein wastewater and seawater were adequately mixed and passed via a disinfection tank under the natural flow with sunlight irradiation.

Behavior of Generated Gas during Femtosecond Laser Lens Irradiation in Porcine Cadaver Eyes

(1) Background: We investigated the behavior of gas inside a lens and its influence on the lens capsule, which may cause complications by lens irradiation with a femtosecond laser cataract surgery device. (2) Methods: The crystalline lenses of 6-month-old porcine cadaver eyes were observed during laser irradiation. An intraocular endoscope in the vitreous cavity was used to measure the posterior capsule position. Optical coherence tomography measurements of the anterior chamber depth before and after the laser irradiation, as well as measurements of the equatorial perimeter of the extracted lens, were compared with those of the controls. (3) Results: Femtosecond laser-generated gas in the porcine lens was dependent on laser irradiation energy. Increases in the amount of laser irradiation energy caused the generated gas to coalesce, move backwards beyond the laser irradiation site, and expand the lens capsule and posterior capsule. (4) Conclusions: The present results suggest that laser irradiation-induced gas moves in the direction of the posterior capsule beyond the lens irradiation site and expands the lens capsule, which may be involved in the development of capsular block syndrome.

Transient Current in Graphene Transistors Under Single- Proton Irradiation

Two-dimensional materials and their multilayers or heterostructures are promising candidates for optoelectronic devices. Their performance such as the transient current can be remarkably modified under irradiation since the atoms are extremely exposed. This effect, however, still lacks theoretical understanding. Using real-time time-dependent density functional theory extended to open systems for electrons and Ehrenfest dynamics for the moving ion, we explore the single-ion irradiation effects on graphene electronics. Perturbed electronic transport is identified in a field-effect transistor setup. The peak transient current is calculated as the key indicator to quantify the irradiation effects, the irradiation-energy dependence of which shows distinction from the stopping power that was well understood in recent studies. We find that the perturbation in transient current is driven by delocalized plasmonic excitation, in contrast to the localized electronic excitation that has a strong impact on the stopping power. The site dependence of transient current is determined by the local electron density and ionic charge, which highlights the roles of the lattice and electronic structures of materials. Following these understandings and the database developed for typical space-irradiation conditions, the device responses of graphene nanoelectronics can be modeled. These results and methods lay the ground for the material-informed design of nanoelectronics in, for example, space applications.

A Sensor Designed to Record Underwater Irradiance with Concern for a Shark’s Spectral Sensitivity

To ascertain how scalloped hammerhead sharks make nightly migrations to their feeding grounds as many as 20 km from their daytime abode, a seamount, a sensor was developed that measured irradiance intensity within the spectral range and sensitivity of the vision of the species. Could the sharks guide their movements by sensing the polarity of irradiation energy radiated from the sun or moon that penetrated into the oceanic depths? Two sensory receptors, cones and rods, are present in the retina of sharks to enable them to see both during daytime and nighttime. The peak sensitivity of the cones is red-shifted due to the presence of these wavelengths during the former period, while their response is linear under the range of the high light levels also present at this time; the peak sensitivity of rods is blue-shifted due to the presence of these wavelengths during dawn, dusk, and nighttime and is linear over the complementary range of low light levels. Spectral response curves for these two receptors were determined for sharks, and an attempt was made to match those of the sensors to the shark’s wavelength perception. The first sensor was matched to the photopic range using a photocell covered with a red-shifted gel filter; the second was matched to the scotopic range using a blue-shifted gel filter.