ABSTRACT
Hot magnetic stars often exhibit incoherent circularly polarized radio emission thought to arise from gyro-synchrotron emission by energetic electrons trapped in the circumstellar ...magnetosphere. Theoretical scalings for electron acceleration by magnetic reconnection driven by centrifugal breakout match well the empirical scalings for observed radio luminosity with both the magnetic field strength and the stellar rotation rate. This paper now examines how energetic electrons introduced near the top of closed magnetic loops are subsequently cooled by the energy loss associated with their gyro-synchrotron radio emission. For sample assumed distributions for energetic electron deposition about the loop apex, we derive the spatial distribution of the radiated energy from such ‘gyro-cooling’. For sub-relativistic electrons, we show explicitly that this is independent of the input energy, but also find that even extensions to the relativistic regime still yield a quite similar spatial distribution. However, cooling by Coulomb collisions with even a modest ambient density of thermal electrons can effectively quench the emission from sub-relativistic electrons, indicating that the observed radio emission likely stems from relativistic electrons that are less affected by such collisional cooling. The overall results form an initial basis for computing radio emission spectra in future models that account for such cooling and multimode excitation about the fundamental gyro-frequency. Though motivated in the context of hot stars, the basic results here could also be applied to gyro-emission in any dipole magnetospheres, including those of ultra-cool dwarfs and even (exo)-planets.
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The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas,
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particle, nuclear and atomic, is ...reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.
Designing of nanomaterials has now become a top-priority research goal with a view to developing specific applications in the biomedical fields. In fact, the recent trends in the literature show that ...there is a lack of in-depth reviews that specifically highlight the current knowledge based on the design and production of nanomaterials. Considerations of size, shape, surface charge and microstructures are important factors in this regard as they affect the performance of nanoparticles (NPs). These parameters are also found to be dependent on their synthesis methods. The characterisation techniques that have been used for the investigation of these nanomaterials are relatively different in their concepts, sample preparation methods and obtained results. Consequently, this review article aims to carry out an in-depth discussion on the recent trends on nanomaterials for biomedical engineering, with a particular emphasis on the choices of the nanomaterials, preparation methods/instruments and characterisations techniques used for designing of nanomaterials. Key applications of these nanomaterials, such as tissue regeneration, medication delivery and wound healing, are also discussed briefly. Covering this knowledge gap will result in a better understanding of the role of nanomaterial design and subsequent larger-scale applications in terms of both its potential and difficulties.
Whether vitamin C (ascorbate) has a role to play as an anti-cancer agent has been debated for decades. Ascorbate has been used by cancer patients in an unregulated environment, either as a dietary ...supplement or in pharmacological doses administered by infusion, with numerous reports of clinical benefit, but in the absence of rigorous clinical trial data. The design of appropriate clinical trials has been hindered by a lack of understanding of the mechanism(s) of action that would inform the choice of effective dose, timing of administration and likely responsive cancer models. More recently, expanded understanding of the biological activities of ascorbate has led to a number of plausible hypotheses for mechanisms of anti-cancer activity. Prominent among these are the generation of significant quantities of hydrogen peroxide by the autoxidation of supra-physiological concentrations of ascorbate and stimulation of the 2-oxoglutarate-dependent dioxygenase family of enzymes (2-OGDDs) that have a cofactor requirement for ascorbate. Hydrogen peroxide generation is postulated to generate oxidative stress that preferentially targets cancer cells. The 2-OGDDs include the hydroxylases that regulate the hypoxic response, a major driver of tumor survival, angiogenesis, stem cell phenotype and metastasis, and the epigenetic histone and DNA demethylases. The latter are of particular interest, with recent studies suggesting a promising role for ascorbate in the regulation of the ten-eleven translocase (TET) DNA demethylases in hematological cancers. Support for these proposed mechanisms has come from many
studies, and xenograft animal models have consistently shown an anti-cancer effect of ascorbate administration. However, decisive evidence for any particular mechanism(s) of action is not yet available from an
setting. With a number of early phase clinical trials currently underway, evidence for potential mechanism(s) of action is required to inform the most appropriate study design and choice of cancer model. Hopefully such information will result in sound clinical data that will avert adding any further controversy to this already contentious debate.
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•Contaminants present in refinery wastewater treated in continuous mode MFC operation.•Continuous mode operation showed higher performance (225±1.4mW/m2) over batch mode.•GC ...chromatogram showed significant removal of hydrocarbon content of C6 to C40.•Phenol and sulfide removal was also significant in continuous mode operation.•Projected power yields showed the possibility of process up-scaling.
Refinery wastewater (RW) treatment in microbial fuel cell (MFC) was studied in batch mode operation followed by continuous mode operation with 8h and 16h hydraulic retention time (HRT). The MFC performance was evaluated in terms of power density, organics removal, specific contaminants (oil & grease, phenol and sulfide) removal and energy conversion efficiency with respect to operation mode. Higher power density of 225±1.4mW/m2 was observed during continuous mode operation with 16h HRT along with a substrate degradation of 84.4±0.8% including the 95±0.6 of oil content. The columbic efficiency during this operation was about 2±0.8% and the projected power yield was 340±20kWh/kg CODR/day. Batch mode operation also showed good substrate degradation (81±1.8%) but took longer HRT which resulted in significantly low substrate degradation rate (0.036±0.002kgCODR/m3-day) over continuous mode operation (1.05±0.01kgCODR/m3-day). Overall, current study depicted the possibility of utilizing RW as substrate in MFC for power generation along with its treatment.
Resistance to conventional anticancer therapies in patients with advanced solid tumors has prompted the need of alternative cancer therapies. Moreover, the success of novel cancer therapies depends ...on their selectivity for cancer cells with limited toxicity to normal tissues. Several decades after Coley's work a variety of natural and genetically modified non-pathogenic bacterial species are being explored as potential antitumor agents, either to provide direct tumoricidal effects or to deliver tumoricidal molecules. Live, attenuated or genetically modified non-pathogenic bacterial species are capable of multiplying selectively in tumors and inhibiting their growth. Due to their selectivity for tumor tissues, these bacteria and their spores also serve as ideal vectors for delivering therapeutic proteins to tumors. Bacterial toxins too have emerged as promising cancer treatment strategy. The most potential and promising strategy is bacteria based gene-directed enzyme prodrug therapy. Although it has shown successful results in vivo yet further investigation about the targeting mechanisms of the bacteria are required to make it a complete therapeutic approach in cancer treatment.
This is a cross-sectional study of 29 published cases of acute myopericarditis following COVID-19 mRNA vaccination. The most common presentation was chest pain within 1–5 days after the second dose ...of mRNA COVID-19 vaccination. All patients had an elevated troponin. Cardiac magnetic resonance imaging revealed late gadolinium enhancement consistent with myocarditis in 69% of cases. All patients recovered clinically rapidly within 1–3 weeks. Most patients were treated with non-steroidal anti-inflammatory drugs for symptomatic relief, and 4 received intravenous immune globulin and corticosteroids. We speculate a possible causal relationship between vaccine administration and myocarditis. The data from our analysis confirms that all myocarditis and pericarditis cases are mild and resolve within a few days to few weeks. The bottom line is that the risk of cardiac complications among children and adults due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection far exceeds the minimal and rare risks of vaccination-related transient myocardial or pericardial inflammation.
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•Cobalt doped Graphitic carbon nitride (g-CN) was synthesized chemically.•Thermal stability and Photoluminescence properties have been studied.•As prepared samples were used in ...visible light induced removal of toxic Eosin B dye.•Enhancement of photocatalytic activity after doping has been observed and discussed.
A simple method for synthesis of layered graphitic carbon nitride and its doping with cobalt has been reported. The as synthesized samples were characterized by X-ray diffraction (XRD), field emission scanning and transmission electron microscope (FESEM, TEM), BET, UV–vis and photoluminescence (PL) spectrophotometer. XRD confirmed the proper phase formation whereas sheet like morphology was observed from FESEM and TEM study. EDX analysis confirmed the presence of cobalt. TG-DTA study revealed the increased stability of graphitic carbon nitride upon introduction of dopants. Surface area and pore size distributions of the pure and doped samples were studied from BET analysis. PL spectra of both the samples have been studied. Degradation of Eosin B dye was performed by both the samples. The doped sample showed enhancement of the visible light photocatalytic activity. It is speculated that the dopant induced trapping of electrons facilitates the separation of charged carriers thus giving better photocatalytic activity.
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