Exploring the conformational space of cyclic peptides by a stochastic search method

A stochastic search algorithm is applied in order to probe the conformations of cyclic peptides. The search is conducted in two stages. In the first stage, random conformations are generated and evaluated by a penalty function for ring closure ability, following a stepwise construction of each amino acid into the peptide by a random choice of one of its allowed conformations. The allowed conformational ranges of backbone dihedral angles for each amino acid have been extracted from a Data Bank of diverse proteins. Values of dihedral angles that do not contribute favorably to the scoring of ring closure are retained or discarded by a statistical test. Values are discarded up to a point from which all remaining combinations of angles are constructed, scored, sorted, and clustered. In the second stage, side chains have been added and fast optimization was applied to the set of diverse conformations in a "united atoms" approach, with the "Kollman forcefield" of Sybyl 6.8. This iterative stochastic elimination algorithm finds the global minimum and most of the best results, when compared to a full exhaustive search in appropriately sized problems. In larger problems, we compare the results to experimental structures. The root mean square deviation (RMSD) of our best results compared to crystal structures of cyclic peptides with sizes from 4 to 15 amino acids are mostly below 1.0 A up to 8 mers and under 2.0 A for larger cyclic peptides.     

Tube inlet orifice design of a once-through steam generator for flow stabilization

A numerical study is conducted on the secondary side screw-type tube inlet orifice design of a once-through steam generator. An orifice length criterion for flow stabilization is derived by introducing the hydraulic resistance ratio of the orifice and the subcooled region to the two-phase and superheated regions. Various tube plugging conditions and power levels are considered, and the secondary coolant pressure at the tube outlet is adjusted to maintain a constant thermal power. Comprehensive numerical solutions are acquired to evaluate the minimum orifice length under various operating conditions. The results obtained show that a constant thermal power is maintained by properly adjusting the secondary coolant outlet pressure with a variation of the superheat degree and secondary coolant pressure drop when the steam generator operates at high power level. The steam generator performance is analyzed according to the tube plugging condition in terms of the degree of superheat, secondary side pressure drop, temperature distribution, and quality distribution. The secondary side outlet pressure curve for the constant thermal power operation is obtained, and the required minimum orifice length to suppress the flow oscillation below the allowable level is evaluated. The lowest power level results in the highest minimum orifice length, and non-plugging condition provides a limiting case for the orifice length criterion except near the 100 % power level.

     

Controlling the structural,microstructure and magnetic properties of barium W-type hexaferrite elaborated using tartaric acid precursor strategy

In this study, barium W-type hexaferrite (BaCo₂Fe₁₆O₂₇) nanopowders have purposefully fabricated through tartaric acid precursor method using inexpensive starting materials. In this regards, the impact of the synthesis conditions namely the annealing temperature and the Ba:Co molar ratio on the crystal structure, crystallite size, microstructure and magnetic structure was explored using X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer. For instance, well crystalline W-type hexaferrite was realized for the precursors annealed at a low temperature of 1100 °C for 2 h using two different Ba:Co molar ratios of 1.1:2.2 and 1.2:2.4. The crystallite size, the lattice constant, the aspect ratio as well as the unit cell volume were substantially affected with the Ba:Co molar ratio and the annealing temperature. Remarkably, the morphology of hexaferrite powders can be controlled by adjusting the annealing temperature and the Ba:Co molar ratio. Clearly, the microstructure of the formed powders was improved to a hexagonal platelet-like structure by raising the annealing temperature. Eventually, maximum saturation magnetization Ms?=?72.3 emu/g was accomplished for W-hexaferrite particles obtained with Ba:Co molar ratio 1.1:2.2 annealed at 1350 °C for 2 h. Wide coercivities (196–1097 Oe) were achieved at the different synthesis conditions.     

Emotion Recognition from Occluded Facial Images Using Deep EnsembleModel

Facial expression recognition has been a hot topic for decades, but high intraclass variation makes it challenging. To overcome intraclass variation for visual recognition, we introduce a novel fusion methodology, in which the proposed model first extract features followed by feature fusion. Specifically, RestNet-50, VGG-19, and Inception-V3 is used to ensure feature learning followed by feature fusion. Finally, the three feature extraction models are utilized using Ensemble Learning techniques for final expression classification. The representation learnt by the proposed methodology is robust to occlusions and pose variations and offers promising accuracy. To evaluate the efficiency of the proposed model, we use two wild benchmark datasets Real-world Affective Faces Database (RAF-DB) and AffectNet for facial expression recognition. The proposed model classifies the emotions into seven different categories namely: happiness, anger, fear, disgust, sadness, surprise, and neutral. Furthermore, the performance of the proposed model is also compared with other algorithms focusing on the analysis of computational cost, convergence and accuracy based on a standard problem specific to classification applications.     

Optical and magnetic properties of CuO/CuFe2O4 nanocomposites

CuO/c-CuFe₂O₄ nanocomposites have been synthesized via the oxalate precursor route. Effect of synthesis conditions on the crystal structure, microstructure, magnetic and optical properties of the formed powders was studied. The results indicated that pure CuO nanoparticles were obtained from the oxalate precursor annealed at 600 °C for 2 h. However, substitution of Cu²⁺ ion by Fe³⁺ ion (Cu_1?X Fe _X O, where X = 0, 0.05, 0.1 and 0.2) led to form of CuO/CuFe₂O₄ nanocomposites. The microstructures of the powders appeared as a monoclinic like shape. Furthermore, the band gap energy of the obtained CuO nanopowders was 1.41 eV and the value was slightly decreased by Fe³⁺ ion substitution. In addition, the formed CuO particles had weak ferromagnetic characteristics. However, the substitution Cu²⁺ ion by Fe³⁺ ion enhanced the magnetic properties of the formed composite as the result of increasing the CuFe₂O₄ phase formation. Hence, the saturation magnetization was increased from 0.13 to 9.8 emu/g by increasing the Fe³⁺ ion from 0 to 0.2.     

Sequential approximate optimization of industrial hammer peening using finite element simulations

In this paper, the industrial hammer peening process is optimized using multi-objective, sequential approximate optimization, which is a mathematics- plus finite element- based algorithm. Since the number of design and objective variables is significant, the global optimization problem is split into two, more manageable multi-objective subproblems. The use of surrogate modelling together with an intensification and diversification strategy for solving the optimization subproblems allows for significant computational cost savings without loss of accuracy. Additionally, we propose a Bayesian inference criterion-based sensitivity approach for “filtering-out” design variables which do not significantly affect objectives variables. Finally, guidelines for selecting appropriate Pareto optima are given using \(N-1\) Pareto diagrams, where N is the number of objective variables.     

Crosstalk between Sodium–Glucose Cotransporter Inhibitors and Sodium–Hydrogen Exchanger 1 and 3 in Cardiometabolic Diseases

Abnormality in glucose homeostasis due to hyperglycemia or insulin resistance is the hallmark of type 2 diabetes mellitus (T2DM). These metabolic abnormalities in T2DM lead to cellular dysfunction and the development of diabetic cardiomyopathy leading to heart failure. New antihyperglycemic agents including glucagon-like peptide-1 receptor agonists and the sodium–glucose cotransporter-2 inhibitors (SGLT2i) have been shown to attenuate endothelial dysfunction at the cellular level. In addition, they improved cardiovascular safety by exhibiting cardioprotective effects. The mechanism by which these drugs exert their cardioprotective effects is unknown, although recent studies have shown that cardiovascular homeostasis occurs through the interplay of the sodium–hydrogen exchangers (NHE), specifically NHE1 and NHE3, with SGLT2i. Another theoretical explanation for the cardioprotective effects of SGLT2i is through natriuresis by the kidney. This theory highlights the possible involvement of renal NHE transporters in the management of heart failure. This review outlines the possible mechanisms responsible for causing diabetic cardiomyopathy and discusses the interaction between NHE and SGLT2i in cardiovascular diseases.     

First web space contracture and hand function

Near-infrared spectroscopy (NIRS) was used to monitor human visual cortical function during and after photic stimulation (PS) in five adult volunteers. Cerebral blood volume (CBV) increased on the occipital surface during PS, but NIRS parameters did not change on the frontal surface. The increase in CBV was caused by a rapid increase in oxyhemoglobin with but a small increase in deoxyhemoglobin, suggesting cerebral vascular dilatation with decreased oxygen consumption. After PS stopped, CBV promptly decreased and then slightly increased again. Cytochrome aa3 did not show any change during and after PS. These phenomena reappeared following repeated PS in all five subjects. These results may represent the first step in the development of NIRS imaging.     

A data-driven approach to multi-product production network planning

The clearing function models the non-linear relationship between work-in-process and throughput and has been proposed for production planning in environments with queuing (congestion) effects. One approach in multi-product, multi-stage environments has been to model the clearing function at the bottleneck machine only. However, since the bottleneck shifts as the product release mix changes, this approach has its limitations. The other approach is the Alternative Clearing Function formulation, where the clearing function is first estimated at the resource level using piecewise linear regression from simulation experiments, and then embedded into a linear programme. This paper develops an alternative to the Allocated Clearing Function formulation, wherein system throughput is estimated at discrete work-in-process points. A mixed integer programming formulation is then presented to use these throughput estimates for discrete release choices. The strength of the formulation is illustrated with a numerical example and the new approach is compared with the ACF.     

Thoracic outlet syndrome

A careful history and thorough physical examination are the most important components in establishing the diagnosis of TOS. The use of radiographic and laboratory tests, when indicated, can improve the diagnostic yield. Provocative positional maneuvers must be evaluated for their vascular and, more important, for their neurologic response. These maneuvers do not "make" the diagnosis, but they can be a useful adjunct for confirming the diagnosis. Vascular TOS is less common and often requires surgical treatment. Neurologic TOS is very common but less frequently requires surgical treatment. The surgical approach and procedure selection should be determined by the nature of the pathologic condition and site of compression.