Study of stress intensity factor on the anisotropic machining behavior of single crystal sapphire

The ductile–brittle transition was investigated based on material crystallography and stress intensity factor on the four distinctive planes of sapphire. Cutting forces were analyzed to explain the anisotropic transition characteristics. The projected stress on the objective plane at the transition point was estimated from the critical stress intensity factor of the corresponding crystal plane. Per cutting direction, the effect of crystal planes on the machinability was discussed, and the estimated stress was compared with measured values. Experimental results showed that the anisotropic machinability can be predicted in terms of crystal orientation and the critical stress intensity factor.     

New Anthraquinone‐Based Conjugated Microporous Polymer Cathode with Ultrahigh Specific Surface Area for High‐Performance Lithium‐Ion Batteries

Redox‐active conjugated microporous polymers (RCMPs) polymerized by conventional methods are commonly obtained as irregular insoluble solid particles making the electrode processing difficult. In this work, the synthesis of RCMP based on anthraquinone moieties (IEP‐11) is developed via a two‐step pathway combining miniemulsion and solvothermal techniques that results in polymer nanostructures that are much easier to disperse in solvents facilitating the fabrication of electrodes. Interestingly, this synthetic approach is also found to have an important impact on the inherent morphology of IEP‐11 that exhibits a dual porosity combining micro and mesopores with a specific surface area as high as 2200 m² g^?1, which is one of the highest values reported for RCMPs. Moreover, the compactness of the electrodes is also improved, the resulting electrodes have triple the density than those obtained with conventional methods. Consequently, when these electrodes are tested as cathodes in Li‐ion battery, they deliver high gravimetric capacities (≈100 mAh g^?1) and extraordinary rate capability keeping 76% of discharge capacity when charged–discharged in only 12 min (@5 C). Moreover, the insoluble and robust conjugated porous structure provides IEP‐11‐E12 with an unprecedented cycling stability retain ≈90% and ≈60% of its initial capacity after 5000 (@2 C) and 80 000 cycles (@30 C), respectively.     

A deep analysis on optimization techniques for appropriate PID tuning to incline efficient artificial pancreas

Neural Computing and Applications - Juvenile diabetes or a type-1 diabetic can be seen in 5% of the patients, who affected by this form of the disease. The type-1 diabetic can be seen mostly in...     

Candidate Alzheimer’s Disease Biomarker miR-483-5p Lowers TAU Phosphorylation by Direct ERK1/2 Repression

MicroRNAs have been demonstrated as key regulators of gene expression in the etiology of a range of diseases including Alzheimer’s disease (AD). Recently, we identified miR-483-5p as the most upregulated miRNA amongst a panel of miRNAs in blood plasma specific to prodromal, early-stage Alzheimer’s disease patients. Here, we investigated the functional role of miR-483-5p in AD pathology. Using TargetScan and miRTarBase, we identified the microtubule-associated protein MAPT, often referred to as TAU, and the extracellular signal-regulated kinases 1 and 2 (ERK1 and ERK2), known to phosphorylate TAU, as predicted direct targets of miR-483-5p. Employing several functional assays, we found that miR-483-5p regulates ERK1 and ERK2 at both mRNA and protein levels, resulting in lower levels of phosphorylated forms of both kinases. Moreover, miR-483-5p-mediated repression of ERK1/2 resulted in reduced phosphorylation of TAU protein at epitopes associated with TAU neurofibrillary pathology in AD. These results indicate that upregulation of miR-483-5p can decrease phosphorylation of TAU via ERK pathway, representing a compensatory neuroprotective mechanism in AD pathology. This miR-483-5p/ERK1/TAU axis thus represents a novel target for intervention in AD.     

Development of olmesartan medoxomil optimized nanosuspension using the Box–Behnken design to improve oral bioavailability

The aim of the present investigation was to enhance the oral bioavailability of olmesartan medoxomil by improving its solubility and dissolution rate by preparing nanosuspension (OM-NS), using the Box–Behnken design. In this, four factors were evaluated at three levels. Independent variables include: concentration of drug (X₁), concentration of surfactant (X₂), concentration of polymer (X₃) and number of homogenization cycles (X₄). Based on preliminary studies, the size (Y₁), zeta potential (ZP) (Y₂) and % drug release at 5?min (Y₃) were chosen as dependent responses. OM-NS was prepared by high pressure homogenization method. The size, PDI, ZP, assay, in vitro release and morphology of OM-NS were characterized. Further, the pharmacokinetic (PK) behavior of OM-NS was evaluated in male wistar rats. Statistically optimized OM-NS formulation exhibited mean particle size of 492?nm, ZP of –27.9?mV and 99.29% release in 5?min. OM-NS showed more than four times increase in its solubility than pure OM. DSC and XRD analyses indicated that the drug incorporated into OM-NS was in amorphous form. The morphology of OM-NS was found to be nearly spherical with high dispersity by scanning electron microscopic studies. The PK results showed that OM lyophilized nanosuspension (NS) exhibited improved PK properties compared to coarse powder suspension and marketed tablet powder suspension (TS). Oral bioavailability of lyophilized NS was increased by 2.45 and 2.25 folds when compared to marketed TS and coarse powder suspension, respectively. Results of this study lead to conclusion that NS approach was effective in preparing OM formulations with enhanced dissolution and improved oral bioavailability.     

A meta‐heuristic Bayesian network classification for intrusion detection

Software‐defined networking (SDN) is an innovative network paradigm much in demand today in academics and industry. In this network, the SDN controller must be able to observe and examine traffic flow through the network systems. However, intrusion‐based data packets affect the whole system is a major drawback. To overcome this issue, we propose a Novel Agent Program (NAP) framework for preventing switches from the external compromised attacks. A Meta‐Heuristic Bayesian Network Classification (MHBNC) algorithm for intrusion detection is proposed in this paper. The proposed algorithm follows certain procedures for preprocessing, feature selection, feature optimization, and classification. Normal and anomaly‐based data packets are classified successfully with its improved detection capabilities based on the optimization technique. The simulation results of the proposed ID_MBC (intrusion detection based on meta‐heuristic Bayesian classifier) technique is compared with existing techniques such as the association rule, PSO+GA, and the GA+RVM. The proposed MHBNC classifier performs better than existing methods.     

Nematic Phases in 1,2,4‐Oxadiazole‐Based Bent‐Core Liquid Crystals: Is There a Ferroelectric Switching?

Four series of new 1,2,4‐oxadiazole derived bent‐core liquid crystals incorporating one or two cyclohexane rings are synthesized and investigated by optical polarizing microscopy, differential scanning calorimetry (DSC), X‐ray diffraction (XRD), electro‐optical, and dielectric investigations. All the compounds exhibit wide ranges of nematic phases composed of tilted smectic (SmC‐type) cybotactic clusters with strongly tilted aromatic cores (40–57°) and show a distinct peak in the current curves observed under a triangular wave field. Dielectric spectroscopy of aligned samples corroborates the previously proposed polar structure of the cybotactic clusters and the ferroelectric‐like polar switching of these nematic phases. Hence, it is shown that this is a general feature of the nematic phases of structurally different 3,5‐diphenyl‐1,2,4‐oxadiazole derivatives. In these uniaxial nematic phases there is appreciable local biaxiality and polar order in the cybotactic clusters. As a second point it is shown that electric field induced fan‐like textures, as often observed for the nematic phases of bent‐core liquid crystals, do not indicate the formation of a smectic phase, rather they represent special electro‐convection patterns due to hydrodynamic instabilities.     

Effect of Fluid Inertia on Journal Bearing Parameters

In the modeling and analysis of rotordynamic systems with journal bearings, the stiffness and damping parameters are usually obtained from the Reynolds equation of hydrodynamic lubrication. The Reynolds equation is derived from the continuity and momentum equations with several assumptions; the principal one among them being that the inertia terms are negligible since the lubricant flow is viscosity-dominated. Some previous work has shown, however, that the effect of fluid inertia on the static and dynamic properties of a bearing is not negligible in many circumstances.

This paper uses a perturbation approach to present a rigorous derivation of the correction terms to be added to account for the effect of inertia in the case of a journal on a short bearing. The governing equation for pressure correction is derived and the corrected stiffness, damping, and inertia coefficients to the first order are displayed as a function of the equilibrium position.     

The security-based optimization algorithm for enhancing the energy efficiency of wireless sensor networks

In the upcoming era, one of the emergent technologies is “Wireless Sensor Networks (WSNs),” which has provided various solutions in the field of defense, surveillance, and so on. But the main problems in the WSNs are security and energy-efficient routing to the researchers. The deployment of security algorithms can monitor only the unauthorized signals to ensure security, but it lacks and leads to higher energy consumption, whereas the deployment of energy-efficient routing algorithms is used only for the selection of routing paths, but it fails to ensure security. Hence, the main intent of this research work is to solve both problems by the following proposed models. Model 1 is “Identity-Based Aggregate Signatures (IBAS)” that is the most effective security-based framework protocol in this research work. Model 2 is the integration of IBAS and “Fuzzy Logic System (FLS)” that acts as an energy-efficient algorithm, and here, FLS is used to find the optimal path from source to destination to transmit the data. Model 3 is the combination of IBAS and the “Whale Optimization Algorithm (WOA)” for higher energy efficiency and auto localization by analyzing the entire route in WSN. Model 4 is the combination of IBAS, WOA, and the “Reinforcement Theory of WOA (RTWOA)” energy-efficiency model with a twofold and weight factor strategy for better speed and accuracy. These models ensure security, energy efficiency, and auto localization. The simulation parameters such as “Energy Efficiency,” “Packet Delivery Ratio,” “Average delay,” “Throughput,” and “Energy Consumption” are evaluated, and results show that the performance of energy efficiency and security is higher in Model 4 when compared to the other three models.