Collective Modes of Massive Dirac Fermions in Armchair Graphene Nanoribbons

We report the plasmon dispersion characteristics of intrinsic and extrinsic armchair graphene nanoribbons of atomic width N = 5 using a p_z-orbital tight binding model with third-nearest-neighbor (3nn) coupling. The coupling parameters are obtained by fitting the 3nn dispersions to that of an extended Huckel theory. The resultant massive Dirac Fermion system has a band gap E_g \approx 64 meV. The extrinsic plasmon dispersion relation is found to approach a common dispersion curve as the chemical potential $\mu$ increases, whereas the intrinsic plasmon dispersion relation is found to have both energy and momentum thresholds. We also report an analytical model for the extrinsic plasmon group velocity in the q \rightarrow 0 limit

Armchair graphene nanoribbons: Electronic structure and electric field modulation

We report electronic structure and electric field modulation calculations in the width direction for armchair graphene nanoribbons (acGNRs) using a semi-empirical extended Huckel theory. Important band structure parameters are computed, e.g. effectives masses, velocities and bandgaps. For the three types of acGNRs, the pz orbital tight-binding parameters are extracted if feasible. Furthermore, the effect of electric field in the width direction on acGNRs dispersion is explored. It is shown that for the two types of semiconducting acGNRs, an external electric field can reduce the bandgap to a few meV with different quantitative behavior.Comment: 5 pages, 5 figure

POTENCY AND SAFETY TESTING OF HAEMORRHAGIC SEPTICAEMIA OIL ADJUVANTED VACCINE IN SWISS ALBINO MICE

The present study was conducted to evaluate the potency and safety of haemorrhagic septicaemia oil adjuvant vaccine in Swiss albino mice via subcutaneous route of inoculation. The vaccine was proved successful as it gave 70 to 100% protection in Swiss albino mice

Low frequency noise statistics for the breakdown characterization of ultra-thin gate oxides

We have investigated the statistics of low frequency noise in the tunneling current of ultrathin oxides (2.5nm-4nm) in metal oxide semiconductor capacitors as a function of the applied voltage stress. The statistical analysis includes (i) non-Gaussianity (nG), which is a measure of the degree of temporal correlation in the noise, and (ii) ratio of integrated noise power to the DC leakage current (R). The occurrence of high peaks in nG indicates the appearance of new percolation paths, and the subsequent conduction through these paths is indicated by R. Our results show that the nG and R characteristics are generic for the oxides of different thickness and growth quality and have the potential, in conjunction with leakage itself, of being used as a prognosticator of oxide reliability.Comment: 4 page

Apigenin role as cell-signaling pathways modulator: implications in cancer prevention and treatment

Cancer is a complex disease orchestrated by various extrinsic and intrinsic pathways. In recent years, there has been a keen interest towards the development of natural extracts-based cancer therapeutics with minimum adverse effects. In pursuit of effective strategy, a wide variety of natural products-derived compounds have been addressed for their anticancer effects. Apigenin is a naturally-occurring flavonoid present abundantly in various fruits and vegetables. Decades of research have delineated the pharmacological and biological properties of apigenin. Specifically, the apigenin-mediated anticancer activities have been documented in various types of cancer, but the generalized scientific evidence encompassing various molecular interactions and processes, such as regulation of the apoptotic machinery, aberrant cell signaling and oncogenic protein network have not been comprehensively covered. In this sense, in this review we have attempted to focus on the apigenin-mediated regulation of oncogenic pathways in various cancers. We have also addressed the cutting-edge research which has unveiled the remarkable abilities of apigenin to interact with microRNAs to modulate key cellular processes, with special emphasis on the nano-formulations of apigenin that can help their targeted delivery and can be a therapeutic solution for the treatment of various cancers.N.C.-M. acknowledges the Portuguese Foundation for Science and Technology under the Horizon 2020 Program (PTDC/PSI-GER/28076/2017)

Advances in “Omics” Approaches for Improving Toxic Metals/Metalloids Tolerance in Plants

Food safety has emerged as a high-urgency matter for sustainable agricultural production. Toxic metal contamination of soil and water significantly affects agricultural productivity, which is further aggravated by extreme anthropogenic activities and modern agricultural practices, leaving food safety and human health at risk. In addition to reducing crop production, increased metals/metalloids toxicity also disturbs plants’ demand and supply equilibrium. Counterbalancing toxic metals/metalloids toxicity demands a better understanding of the complex mechanisms at physiological, biochemical, molecular, cellular, and plant level that may result in increased crop productivity. Consequently, plants have established different internal defense mechanisms to cope with the adverse effects of toxic metals/metalloids. Nevertheless, these internal defense mechanisms are not adequate to overwhelm the metals/metalloids toxicity. Plants produce several secondary messengers to trigger cell signaling, activating the numerous transcriptional responses correlated with plant defense. Therefore, the recent advances in omics approaches such as genomics, transcriptomics, proteomics, metabolomics, ionomics, miRNAomics, and phenomics have enabled the characterization of molecular regulators associated with toxic metal tolerance, which can be deployed for developing toxic metal tolerant plants. This review highlights various response strategies adopted by plants to tolerate toxic metals/metalloids toxicity, including physiological, biochemical, and molecular responses. A seven-(omics)-based design is summarized with scientific clues to reveal the stress-responsive genes, proteins, metabolites, miRNAs, trace elements, stress-inducible phenotypes, and metabolic pathways that could potentially help plants to cope up with metals/metalloids toxicity in the face of fluctuating environmental conditions. Finally, some bottlenecks and future directions have also been highlighted, which could enable sustainable agricultural production

Competing beetles attract egg laying in a hawkmoth

In nature, plant-insect interactions occur in complex settings involving multiple trophic levels, often with multiple species at each level.1 Herbivore attack of a host plant typically dramatically alters the plant’s odor emission in terms of concentration and composition.2,3 Therefore, a well-adapted herbivore should be able to predict whether a plant is still suitable as a host by judging these changes in the emitted bouquet. Although studies have demonstrated that oviposition preferences of successive insects were affected by previous infestations,4,5 the underlying molecular and olfactory mechanisms remain unknown. Here, we report that tobacco hawkmoths (Manduca sexta) preferentially oviposit on Jimson weed (Datura wrightii) that is already infested by a specialist, the three-lined potato beetle (Lema daturaphila). Interestingly, the moths’ offspring do not benefit directly, as larvae develop more slowly when feeding together with Lema beetles. However, one of M. sexta’s main enemies, the parasitoid wasp Cotesia congregata, prefers the headspace of M. sexta-infested plants to that of plants infested by both herbivores. Hence, we conclude that female M. sexta ignore the interspecific competition with beetles and oviposit deliberately on beetle-infested plants to provide their offspring with an enemy-reduced space, thus providing a trade-off that generates a net benefit to the survival and fitness of the subsequent generation. We identify that α-copaene, emitted by beetle-infested Datura, plays a role in this preference. By performing heterologous expression and single-sensillum recordings, we show that odorant receptor (Or35) is involved in α-copaene detection.Publikationsfonds ML

Primary recovery factor as a function of production rate: implications for conventional reservoirs with different drive mechanisms

This study evaluates the dependency of production rate on the recovery of hydrocarbon from conventional reservoirs using MBAL simulator. The results indicated that the recoveries are sensitive to the production rate in almost all hydrocarbon reservoirs. It was also found that the recovery of volumetric gas drive reservoirs is not impacted by the production rate. In fact, any increase in the production rate improves gas recovery in weak and strong water drive reservoirs. Moreover, increasing the production rate in oil reservoirs decreases the recovery with a significant effect observed in the weak water drive reservoirs. The results of this study demonstrate the need for implementing an effective reservoir management in order to obtain a maximum recovery

Differential glucocorticoid metabolism in patients with persistent versus resolving inflammatory arthritis

Introduction: Impairment in the ability of the inflamed synovium to generate cortisol has been proposed to be a factor in the persistence and severity of inflammatory arthritis. In the inflamed synovium, cortisol is generated from cortisone by the 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme. The objective of this study was to determine the role of endogenous glucocorticoid metabolism in the development of persistent inflammatory arthritis. Methods: Urine samples were collected from patients with early arthritis (symptoms ≤12 weeks duration) whose final diagnostic outcomes were established after clinical follow-up and from patients with established rheumatoid arthritis (RA). All patients were free of disease-modifying anti-rheumatic drugs at the time of sample collection. Systemic measures of glucocorticoid metabolism were assessed in the urine samples by gas chromatography/mass spectrometry. Clinical data including CRP and ESR were also collected at baseline. Results: Systemic measures of 11β-HSD1 activity were significantly higher in patients with early arthritis whose disease went on to persist, and also in the subgroup of patients with persistent disease who developed RA, when compared with patients whose synovitis resolved over time. We observed a significant positive correlation between systemic 11β-HSD1 activity and ESR/CRP in patients with established RA but not in any of the early arthritis patients group. Conclusions: The present study demonstrates that patients with a new onset of synovitis whose disease subsequently resolved had significantly lower levels of systemic 11β-HSD1 activity when compared with patients whose synovitis developed into RA or other forms of persistent arthritis. Low absolute levels of 11β-HSD1 activity do not therefore appear to be a major contributor to the development of RA and it is possible that a high total body 11β-HSD1 activity during early arthritis may reduce the probability of disease resolution