A Modified Topology of a High Efficiency Bidirectional Type DC–DC Converter by Synchronous Rectification

A modified Topology to acquire high efficiency of a bidirectional method of DC–DC converter of non-isolated approach is proposed. The modified circuit involves four numbers of switches with their body diodes, passive elements as two inductors as well as a capacitor and the circuit arrangements double boost converters to progress the voltage gain. The input current of the proposed topology divided amongst the two dissimilar values of inductors produces greater efficiency. In the step-down mode, an apparent lessening in voltage gain and also enhanced efficiency can be realized in the recommended system by expending a synchronous rectification. The modified topology shields the technique for presentation of easy control configurations and is used for truncated output voltage with a large current of energy storage systems in the renewable applications as well as hybrid energy source electric vehicle applications. The simulation of the projected structure has been conducted through MATLAB/Simulink software and has been corroborated through a 12 V/180 V, 200 Watts experimental prototype circuit.publishedVersio

Biochemical characterization of a psychrophilic and halotolerant α–carbonic anhydrase from a deep-sea bacterium, <i>Photobacterium profundum</i>

Prokaryotic α–carbonic anhydrases (α-CA) are metalloenzymes that catalyze the reversible hydration of CO2 to bicarbonate and proton. We had reported the first crystal structure of a pyschrohalophilic α–CA from a deep-sea bacterium, Photobacterium profundum SS9. In this manuscript, we report the first biochemical characterization of P. profundum α–CA (PprCA) which revealed several catalytic properties that are atypical for this class of CA's. Purified PprCA exhibited maximal catalytic activity at psychrophilic temperatures with substantial decrease in activity at mesophilic and thermophilic range. Similar to other α–CA's, Ppr9A showed peak activity at alkaline pH (pH 11), although, PprCA retained 88% of its activity even at acidic pH (pH 5). Exposing PprCA to varying concentrations of oxidizing and reducing agents revealed that N-terminal cysteine residues in PprCA may play a role in the structural stability of the enzyme. Although inefficient in CO2 hydration activity under mesophilic and thermophilic temperatures, PprCA exhibited salt-dependent thermotolerance and catalytic activity under extreme halophilic conditions. Similar to other well-characterized α–CA's, PprCA is also inhibited by monovalent anions even at low concentrations. Finally, we demonstrate that PprCA accelerates CO2 biomineralization to calcium carbonate under alkaline conditions

Numerical Investigation of Boundary Conditions for Moving Contact Line Problems

When boundary conditions arising from the usual hydrodynamic assumptions are applied, analyses of dynamic wetting processes lead to a well-known nonintegrable stress singularity at the dynamic contact line, necessitating new ways to model this problem. In this paper, numerical simulations for a set of representative problems are used to explore the possibility of providing material boundary conditions for predictive models of inertialess moving contact line processes. The calculations reveal that up to Capillary number Ca=0.15, the velocity along an arc of radius 10Li (Li is an inner, microscopic length scale! from the dynamic contact line is independent of the macroscopic length scale a for a.103Li , and compares well to the leading order analytical ‘‘modulated-wedge’’ flow field [R. G. Cox, J. Fluid Mech. 168, 169 (1986)] for Capillary number Ca,0.1. Systematic deviations between the numerical and analytical velocity field occur for 0.1168, 169 (1986)] is used as a boundary condition along an arc of radius R=10-2a from the dynamic contact line, agree well with those using two inner slip models for Ca\u3c0.1, with a breakdown at higher Ca. Computations in a cylindrical geometry reveal the role of azimuthal curvature effects on velocity profiles in this vicinity of dynamic contact lines. These calculations show that over an appropriate range of Ca, the velocity field and the meniscus slope in a geometry-independent region can potentially serve as material boundary conditions for models of processes containing dynamic contact lines

TDP-43 Identified from a Genome Wide RNAi Screen for SOD1 Regulators

Amyotrophic Lateral Sclerosis (ALS) is a late-onset, progressive neurodegenerative disease affecting motor neurons in the brain stem and spinal cord leading to loss of voluntary muscular function and ultimately, death due to respiratory failure. A subset of ALS cases are familial and associated with mutations in superoxide dismutase 1 (SOD1) that destabilize the protein and predispose it to aggregation. In spite of the fact that sporadic and familial forms of ALS share many common patho-physiological features, the mechanistic relationship between SOD1-associated and sporadic forms of the disease if any, is not well understood. To better understand any molecular connections, a cell-based protein folding assay was employed to screen a whole genome RNAi library for genes that regulate levels of soluble SOD1. Statistically significant hits that modulate SOD1 levels, when analyzed by pathway analysis revealed a highly ranked network containing TAR DNA binging protein (TDP-43), a major component of aggregates characteristic of sporadic ALS. Biochemical experiments confirmed the action of TDP-43 on SOD1. These results highlight an unexpected relationship between TDP-43 and SOD1 which may have implications in disease pathogenesis

Protein Glycosylation in Helicobacter pylori: Beyond the Flagellins?

Glycosylation of flagellins by pseudaminic acid is required for virulence in Helicobacter pylori. We demonstrate that, in H. pylori, glycosylation extends to proteins other than flagellins and to sugars other than pseudaminic acid. Several candidate glycoproteins distinct from the flagellins were detected via ProQ-emerald staining and DIG- or biotin- hydrazide labeling of the soluble and outer membrane fractions of wild-type H. pylori, suggesting that protein glycosylation is not limited to the flagellins. DIG-hydrazide labeling of proteins from pseudaminic acid biosynthesis pathway mutants showed that the glycosylation of some glycoproteins is not dependent on the pseudaminic acid glycosylation pathway, indicating the existence of a novel glycosylation pathway. Fractions enriched in glycoprotein candidates by ion exchange chromatography were used to extract the sugars by acid hydrolysis. High performance anion exchange chromatography with pulsed amperometric detection revealed characteristic monosaccharide peaks in these extracts. The monosaccharides were then identified by LC-ESI-MS/MS. The spectra are consistent with sugars such as 5,7-diacetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (Pse5Ac7Ac) previously described on flagellins, 5-acetamidino-7-acetamido-3,5,7,9-tetradeoxy-L-glycero-L-manno-nonulosonic acid (Pse5Am7Ac), bacillosamine derivatives and a potential legionaminic acid derivative (Leg5AmNMe7Ac) which were not previously identified in H. pylori. These data open the way to the study of the mechanism and role of protein glycosylation on protein function and virulence in H. pylori

Root Canal Anatomy of Maxillary and Mandibular Teeth

It is a common knowledge that a comprehensive understanding of the complexity of the internal anatomy of teeth is imperative to ensure successful root canal treatment. The significance of canal anatomy has been emphasized by studies demonstrating that variations in canal geometry before cleaning, shaping, and obturation procedures had a greater effect on the outcome than the techniques themselves. In recent years, significant technological advances for imaging teeth, such as CBCT and micro-CT, respectively, have been introduced. Their noninvasive nature allows to perform in vivo anatomical studies using large populations to address the influence of several variables such as ethnicity, aging, gender, and others, on the root canal anatomy, as well as to evaluate, quantitatively and/or qualitatively, specific and fine anatomical features of a tooth group. The purpose of this chapter is to summarize the morphological aspects of the root canal anatomy published in the literature of all groups of teeth and illustrate with three-dimensional images acquired from micro-CT technology.info:eu-repo/semantics/publishedVersio

Heat shock proteins: A high content assay opportunity to measure cellular stress response

Heat shock proteins (HSPs) have been proposed as therapeutic targets for novel anticancer agents. However, candidates have thus far failed due to low tolerability, limiting their efficacy. This failure highlights our current inability to predict drug toxicity in patients, a Holy Grail in modern drug discovery. Paradoxically, the fundamental role of the tightly regulated HSPs in maintaining homeostasis may constitute an opportunity to monitor drug toxicity. We propose to incorporate the quantification of HSP induction as a key indicator of cellular stress response in multiplexed, high content cell based assay readouts to enhance the predictive power of in vitro drug toxicity profiling outcome

Volume exclusion effect as a driving force for reverse proteolysis: implications for polypeptide assemblage in a macromolecules crowded milieu

Macromolecular crowding, in principle, should affect any reaction that is accompanied by significant reduction in excluded volume. Here we have examined the influence of crowding on reverse proteolysis. We show that proteosynthesis of a polypeptide product with an interacting folding motif such as coiled coil is facilitated in crowded media as a consequence of the volume exclusion effect. Further, we demonstrate that crowding could also effect the conversion of a noncovalent protein complex (fragment complementing protein) obtained by limited proteolysis to the native covalent form, but only if the formation of the native protein results in large compaction leading to a substantial volume exclusion effect. Subtilisin-catalyzed reformation of native triosephosphate isomerase (TIM) from multiple fragments is facilitated by crowding. However, a single nick in ribonuclease S (RNase S) could not be ligated under similar conditions. The failure of generation of RNase A from RNase S is consistent with the fact that the crystal structure of the two forms are almost superimposable, and hence no significant difference of volume exclusion exists between reactant (RNase S) and product (RNase A). In contrast, considerable compaction, and consequently large reduction in excluded volume, is attained through the assembly of a TIM barrel structure. Taken together, these results have implications for both in vitro as well as in vivopolypeptide assemblage by reverse proteolysis

Purification and Preliminary Crystallization of SSA_0908, a Putative Substrate-Binding Protein in \u3ci\u3eStreptococcus sanguinis\u3c/i\u3e

Poster presented at the 2023 SWOSU Research and Scholarly Activity fair. Streptococcus sanguinis is a pathobiont that is the leading cause of subacute infective endocarditis (SIE) in humans. Blood transit and attachment to cardiac vegetation is a prerequisite for SIE pathogenesis. While numerous studies have identified cell-surface adhesins in S. sanguinis, many suggested to be involved in SIE remain uncharacterized. One being SSA_0908, a putative ABC-transporter substrate binding proteins (SBP) with homology to CD0837, a SBP from Clostridiodes difficle implicated in host colonization and aromatic amino acid transport. Sequence analysis showed that residues involved in aromatic amino acid ligand binding is highly conserved in SSA_0908. Homology modeling of SSA_0908 revealed a type 1 periplasmic SBP fold with two a-b-a sandwich domains connected via a hinge-loop. The ligand binding pocket at the interface of the sandwich domains shows active site architecture similar to other aromatic amino acid SBP’s. Sequence and structural homology of SSA_0908 to other characterized aromatic amino acid transporters indicated that this protein may be involved in similar function in S. sanguinis. In order to further characterize SSA_0908, we have successfully over-expressed and purified this protein using affinity chromatography. Preliminary crystallization trials resulted in microcrystals in several conditions. We are currently optimizing crystallization conditions to grow diffraction quality crystals.https://dc.swosu.edu/rf_2023/1004/thumbnail.jp