Since the discovery of second chromosome in
Rhodobacter sphaeroides
2.4.1 in 1989, multipartite genomes have been reported in over three hundred bacterial species under nine different phyla. This has ...shattered the unipartite (single chromosome) genome dogma in bacteria. Since then, many questions on various aspects of multipartite genomes in bacteria have been addressed. However, our understanding of how multipartite genomes emerge and evolve is still lacking. Importantly, the knowledge of genetic factors underlying the differences in multipartite and single-chromosome genomes is lacking. In this work, we have performed comparative evolutionary and functional genomics analyses to identify molecular factors that discriminate multipartite from unipartite bacteria, with the goal to decipher taxon-specific factors, and those that are prevalent across the taxa, underlying these traits. We assessed the roles of evolutionary mechanisms, specifically gene gain, in driving the divergence of bacteria with single and multiple chromosomes. In addition, we performed functional genomic analysis to garner support for our findings from comparative evolutionary analysis. We found genes such as those encoding conserved hypothetical proteins in
Deinococcus radiodurans
R1, and putative phage phi-C31 gp36 major capsid like and hypothetical proteins in
Rhodobacter sphaeroides
2.4.1, which are located on accessory chromosomes in these bacteria but were not found in the inferred ancestral sequences, and on the primary chromosomes, as well as were not found in their closest relatives with single chromosome within the same clade. Our study shines a new light on the potential roles of the secondary chromosomes in helping bacteria with multipartite genomes to adapt to specialized environments or growth conditions.
In the present work, we report the fabrication of a surface-enhanced Raman spectroscopy (SERS) substrate on a simple and easily fabricable hydrophobic surface. The substrates are prepared by slow and ...fast evaporation of a droplet of silver nanoparticle suspension in water. The corresponding identifiers for two substrates are "s_evp" and "f_evp" respectively. It is found that the dried spot size is small on s_evp compared to that on f_evp. This also minimizes the coffee stain effect and enriches the spot in a better way on s_evp compared to f_evp. Consequently, using SERS experimentation on our lab-built setup, concentration as low as 2.5*10
−12
M of rhodamine 6G molecules was detected on s_evp compared to 2.5 × 10
−10
M on f_evp. The proposed s_evp SERS substrate is much easier to fabricate and easy to use compared to super-hydrophobic SERS substrates.
In the present work, we report the fabrication of a surface-enhanced Raman spectroscopy (SERS) substrate on a simple and easily fabricable hydrophobic surface.
SARS-CoV-2 is the causative agent of COVID-19 that has infected over 642 million and killed over 6.6 million people around the globe. Underlying a wide range of clinical manifestations of this ...disease, from moderate to extremely severe systemic conditions, could be genes or pathways differentially expressing in the hosts. It is therefore important to gain insights into pathways involved in COVID-19 pathogenesis and host defense and thus understand the host response to this pathogen at the physiological and molecular level. To uncover genes and pathways involved in the differential clinical manifestations of this disease, we developed a novel gene co-expression network based pipeline that uses gene expression obtained from different SARS-CoV-2 infected human tissues. We leveraged the network to identify novel genes or pathways that likely differentially express and could be physiologically significant in the COVID-19 pathogenesis and progression but were deemed statistically non-significant and therefore not further investigated in the original studies. Our network-based approach aided in the identification of co-expression modules enriched in differentially expressing genes (DEGs) during different stages of COVID-19 and enabled discovery of novel genes involved in the COVID-19 pathogenesis, by virtue of their transcript abundance and association with genes expressing differentially in modules enriched in DEGs. We further prioritized by considering only those enriched gene modules that have most of their genes differentially expressed, inferred by the original studies or this study, and document here 7 novel genes potentially involved in moderate, 2 in severe, 48 in extremely severe COVID-19, and 96 novel genes involved in the progression of COVID-19 from severe to extremely severe conditions. Our study shines a new light on genes and their networks (modules) that drive the progression of COVID-19 from moderate to extremely severe condition. These findings could aid development of new therapeutics to combat COVID-19.
In this work we demonstrate a novel approach to achieve efficient charge separation in dimensionally and dielectrically confined two-dimensional perovskite materials. Two-dimensional perovskites ...generally exhibit large exciton binding energies that limit their application in optoelectronic devices that require charge separation such as solar cells, photo-detectors and in photo-catalysis. Here, we show that by incorporating a strongly electron accepting moiety, perylene diimide organic chromophores, on the surface of the two-dimensional perovskite nanoplatelets it is possible to achieve efficient formation of mobile free charge carriers. These free charge carriers are generated with ten times higher yield and lifetimes of tens of microseconds, which is two orders of magnitude longer than without the peryline diimide acceptor. This opens a novel synergistic approach, where the inorganic perovskite layers are combined with functional organic chromophores in the same material to tune the properties for specific applications.
Summary
We present a partitioned iterative formulation for the modeling of fluid‐structure interaction (FSI) in two‐phase flows. The variational formulation consists of a stable and robust ...integration of three blocks of differential equations, viz, an incompressible viscous fluid, a rigid or flexible structure, and a two‐phase indicator field. The fluid‐fluid interface between the two phases, which may have high density and viscosity ratios, is evolved by solving the conservative phase‐field Allen‐Cahn equation in the arbitrary Lagrangian‐Eulerian coordinates. While the Navier‐Stokes equations are solved by a stabilized Petrov‐Galerkin method, the conservative Allen‐Cahn phase‐field equation is discretized by the positivity preserving variational scheme. Fully decoupled implicit solvers for the two‐phase fluid and the structure are integrated by the nonlinear iterative force correction in a staggered partitioned manner and the generalized‐α method is employed for the time marching. We assess the accuracy and stability of the phase‐field/ALE variational formulation for two‐ and three‐dimensional problems involving the dynamical interaction of rigid bodies with free surface. We consider the decay test problems of increasing complexity, namely, free translational heave decay of a circular cylinder and free rotation of a rectangular barge. Through numerical experiments, we show that the proposed formulation is stable and robust for high density ratios across fluid‐fluid interface and for low structure‐to‐fluid mass ratio with strong added‐mass effects. Overall, the proposed variational formulation produces results with high accuracy and compares well with available measurements and reference numerical data. Using unstructured meshes, we demonstrate the second‐order temporal accuracy of the coupled phase‐field/ALE method via decay test of a circular cylinder interacting with the free surface. Finally, we demonstrate the three‐dimensional phase‐field FSI formulation for a practical problem of internal two‐phase flow in a flexible circular pipe subjected to vortex‐induced vibrations due to external fluid flow.
Polyphenols are natural compounds synthesized exclusively by plants with chemical features related to phenolic substances and eliciting strong antioxidants properties.
The aim of this paper is to ...give a reliable overview of the chemical classification of natural polyphenols.
Literature survey was done through google scholar, pubmed and scopus search engine.
These molecules or classes of natural substances are characterized by two phenyl rings at least and one or more hydroxyl substituents. This description comprehends a large number of heterogeneous compounds with reference to their complexity. Therefore, polyphenols can be simply classified into flavonoids and non-flavonoids, or be subdivided in many sub-classes depending on the number of phenol units within their molecular structure, substituent groups, and/or the linkage type between phenol units. Polyphenols are widely distributed in plant tissues where they mainly exist in form of glycosides or aglycones. The structural diversity of flavonoid molecules arises from variations in hydroxylation pattern and oxidation state resulting in a wide range of compounds: flavanols, anthocyanidins, anthocyanins, isoflavones, flavones, flavonols, flavanones, and flavanonols.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Large-scale activation of graphite felt electrode through a simple and cost-effective method is an imperative need for application of vanadium redox flow battery (VRFB). Here we report a rapid and ...low-cost method to develop highly functionalized activated graphite felt with uniformly distributed surface nanocracks (⁓30 nm × ⁓100 nm). Surface area, size, and distribution of surface nanocracks on electrode were controlled by tuning the process conditions and superior functionality was achieved through nitrogen doping. The activated graphite electrode with highly functionalized surface nanocracks offers improved pathways for electrolyte flow and improved hydrophilicity with high specific surface area (⁓19 m2g−1) for efficient vanadium redox reactions. The VRFB having activated graphite felt and nitrogen-doped alkaline graphite felt yield energy efficiencies as high as 89.6% and 87.4% at 50 mA cm−2, which is 18.3% and 15.4% higher than untreated graphite felt, respectively. Moreover, the VRFBs having activated graphite felt and nitrogen-doped activated graphite felt provide electrolyte utilization of 82.41% and 91.12% at 50 mA cm−2, 91.51% and 111.7% higher than that with untreated graphite felt. Additionally, the VRFBs were able to perform charge-discharge even at high current density of 200 mA cm−2 with electrolyte utilization of 41.78% and 61.09%, respectively.
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•Electrode with uniform surface nanocracks is developed for VRFB.•Electrode offers improved pathways for electrolyte flow and reaction kinetics.•High EE (89%) and electrolyte utilization (91%) are obtained.•Long-term performance during 700 cycles shows no obvious decay in efficiencies.
Abstract Background The long-term outcome of atrial fibrillation (AF) ablation demonstrates attrition. This outcome may be due to failure to attenuate the progressive substrate promoted by ...cardiovascular risk factors. Objectives The goal of this study was to evaluate the impact of risk factor and weight management on AF ablation outcomes. Methods Of 281 consecutive patients undergoing AF ablation, 149 with a body mass index ≥27 kg/m2 and ≥1 cardiac risk factor were offered risk factor management (RFM) according to American Heart Association/American College of Cardiology guidelines. After AF ablation, all 61 patients who opted for RFM and 88 control subjects were assessed every 3 to 6 months by clinic review and 7-day Holter monitoring. Changes in the Atrial Fibrillation Severity Scale scores were determined. Results There were no differences in baseline characteristics, number of procedures, or follow-up duration between the groups (p = NS). RFM resulted in greater reductions in weight (p = 0.002) and blood pressure (p = 0.006), and better glycemic control (p = 0.001) and lipid profiles (p = 0.01). At follow-up, AF frequency, duration, symptoms, and symptom severity decreased more in the RFM group compared with the control group (all p < 0.001). Single-procedure drug-unassisted arrhythmia-free survival was greater in RFM patients compared with control subjects (p < 0.001). Multiple-procedure arrhythmia-free survival was markedly better in RFM patients compared with control subjects (p < 0.001), with 16% and 42.4%, respectively, using antiarrhythmic drugs (p = 0.004). On multivariate analysis, type of AF (p < 0.001) and RFM (hazard ratio 4.8 95% confidence interval: 2.04 to 11.4; p < 0.001) were independent predictors of arrhythmia-free survival. Conclusions Aggressive RFM improved the long-term success of AF ablation. This study underscores the importance of therapy directed at the primary promoters of the AF substrate to facilitate rhythm control strategies.
C-C chemokine receptor (CCR) 5 (CCR5) is the main HIV-1 coreceptor involved in virus entry and cell-to-cell spread during acute and chronic infections: such CCR5 and T cell tropic viruses are adapted ...to and replicate in CD4
memory T cells. Polymorphisms in
regulate CCR5 expression, which, in turn, influences HIV infection acquisition and subsequent disease progression. Among these polymorphisms, a 32-bp deletion in the
open reading frame (
Δ32) and a single nucleotide polymorphism (SNP) in the promoter (-2459G/A) are the most well-characterized polymorphisms.
Δ32 provides partial to full protection against HIV infection and, therefore, serves as a basis for gene deletion studies attempting to achieve a permanent HIV cure. Recent studies have discovered that certain SNPs in the
region, not within
, also affect CCR5 expression, HIV infection, and disease progression. Although these studies provide further valuable information regarding the role of human genetic variation in HIV/AIDS, they did not incorporate -2459G/A. In this article, the author summarizes the knowledge gained through the discovery of these new SNPs and introduces the idea that by not incorporating -2459G/A, less comprehensive conclusions may have been reached. Until a strategy that delivers a cure to the millions is found, every piece of information that may help curtail the HIV/AIDS threat to public health should be considered useful.
Using recent cross-national data, this paper examines the impact of foreign direct investment (FDI) on entrepreneurship activity. The impact of FDI on entrepreneurship is not clear a priori, with ...possibilities of both a negative effect (crowding out) and a positive effect (synergy or complementarity via spillovers). Results find support for the crowding out effect; however, this effect varies across nations with different prevalence of entrepreneurship. Another focus of this work is on gender differences. The crowding out effect is stronger for the foil sample rather than the subsample of female entrepreneurship. This finding stands up to a battery of robustness checks. Policy implications are discussed.
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