Analytical prediction of labyrinth-seal-flow-induced arotor excitation forces

An analytical method to calculate the rotor excitation forces arising from labyrinth seals is presented. The objective is to model the gas flow through the seal clearance passages and cavities when the rotor is positioned eccentricly relative to the stator center. The seal flow model used in the analysis yields solutions which validate the experimentally observed influence of seal parameters on seal forces reported in the literature. The analytically predicted seal pressure distributions and forces were compared with published experimental results

The relaxation of OH (v = 1) and OD (v = 1) by H2O and D2O at temperatures from 251 to 390 K

We report rate coefficients for the relaxation of OH(v = 1) and OD(v = 1) by H2O and D2O as a function of temperature between 251 and 390 K. All four rate coefficients exhibit a negative dependence on temperature. In Arrhenius form, the rate coefficients for relaxation (in units of 10–12 cm3 molecule–1 s–1) can be expressed as: for OH(v = 1) + H2O between 263 and 390 K: k = (2.4 ± 0.9) exp((460 ± 115)/T); for OH(v = 1) + D2O between 256 and 371 K: k = (0.49 ± 0.16) exp((610 ± 90)/T); for OD(v = 1) + H2O between 251 and 371 K: k = (0.92 ± 0.16) exp((485 ± 48)/T); for OD(v = 1) + D2O between 253 and 366 K: k = (2.57 ± 0.09) exp((342 ± 10)/T). Rate coefficients at (297 ± 1 K) are also reported for the relaxation of OH(v = 2) by D2O and the relaxation of OD(v = 2) by H2O and D2O. The results are discussed in terms of a mechanism involving the formation of hydrogen-bonded complexes in which intramolecular vibrational energy redistribution can occur at rates competitive with re-dissociation to the initial collision partners in their original vibrational states. New ab initio calculations on the H2O–HO system have been performed which, inter alia, yield vibrational frequencies for all four complexes: H2O–HO, D2O–HO, H2O–DO and D2O–DO. These data are then employed, adapting a formalism due to Troe (J. Troe, J. Chem. Phys., 1977, 66, 4758), in order to estimate the rates of intramolecular energy transfer from the OH (OD) vibration to other modes in the complexes in order to explain the measured relaxation rates—assuming that relaxation proceeds via the hydrogen-bonded complexes

Design and Development of an Efficient Branch Predictor for an In-order RISC-V Processor

Conditional branches are a serious issue in the pipelined processor. The branch direction and branch target address are determined and calculated by the processor after several cycles of the instruction decode, which results in the pipeline stall. Pipeline stall leads to control hazards in the processor and results in performance degradation. To increase the rate of the instruction flow in modern processors, branch prediction is used. Branch prediction provides an ideal speedup in performance of the processor. The processor predicts the direction in the branch prediction and determines instructions in accordance with the predicted path. The processor tests any prediction for the branch when the branch condition is calculated. If the prediction is incorrect, the processor will automatically abort all instructions taken along the wrong path and return the state to the address of the determined branch. An inaccurate branch predictor results in increased program run-time and leads to higher power consumption. Once the position of a branch is known, the actual target address of the next instruction must also be determined along the expected path. If the branch is expected not to be taken, the destination address is simply the address of the current branch plus the size of the command word. Unless the branch is to be taken, then the target depends on the branch type. The branch target buffer (BTB) can reduce branch efficiency by predicting the branch path and storing information used by branch. There are no stalls if the branch entry is found in BTB, and the calculation is accurate, or the penalty shall be two cycles or more. This paper focuses on the design and development of branch predictor with BTB for the fetch unit, which further integrates to an in-order pipelined RISC-V processor. The performance of the RISC-V core in terms of clock cycle latency, instruction per cycle (IPC), was measured and analyzed

Investigation into the security and privacy of iOS VPN applications

Due to the increasing number of recommendations for people to use Virtual Private Networks (VPNs) to protect their privacy, more application developers are creating VPN applications and publishing them on the Apple App Store and Google Play Store. In this ‘gold rush’, applications are being developed quickly and, in turn, not being developed with security in mind.This paper investigated a selection of VPN applications available on the Apple App Store (for iOS devices) and tested the applications for security and privacy issues. This includes testing for any traffic being transmitted over plain HTTP, DNS leakage and transmission of personally identifiable information (such as phone number, International Mobile Equipment Identity (IMEI), email address, MAC address) and evaluating the security of the tunneling protocol used by the VPN.The testing methodology involved installing VPN applications on a test device, simulating network traffic for a pre-defined period of time and capturing the traffic. This allows for all traffic to be analysed to check for anything being sent without encryption. Other issues that often cause de-anonymization with VPN applications such as DNS leakage were also considered.The research found several common security issues with VPN applications tested, with a large majority of applications still using HTTP and not HTTPS for transmitting certain data. A large majority of the VPN applications failed to route additional user data (such as DNS queries) through the VPN tunnel. Furthermore, just fifteen of the tested applications were found to have correctly implemented the best-recommended tunneling protocol for user security.Outside of the regular testing criteria, other security anomalies were observed with specific applications, which included outdated servers with known vulnerabilities, applications giving themselves the ability to perform HTTPS interception and questionable privacy policies. From the documented vulnerabilities, this research proposes a set of recommendations for developers to consider when developing VPN applications

Characteristics of velopharyngeal dysfunction in 22q11.2 deletion syndrome: A retrospective case-control study

Objective: To identify and describe the dynamic features of velopharyngeal dysfunction (VPD) in patients with 22q11.2 deletion syndrome relative to patients with non-syndromic cleft palates. Study design: Retrospective case-control study. Setting: Pediatric tertiary care center. Subjects and methods: A total of 30 children (aged 9-16 years) with VPD were included in this study. Fifteen children with a definitive diagnosis of 22q11.2 deletion syndrome requiring surgical VPD repair were included in the 22q11.2 deletion syndrome group. Fifteen age-and sex-matched children with non-syndromic cleft palate requiring surgical VPD repair were included in the non-syndromic cleft palate group for comparison. Velar displacement, lateral pharyngeal wall displacement, and lateral pharyngeal wall motion pattern data were extracted from preoperative Multiview Videofluoroscopy imaging studies of all children and compared across groups. Results: Lateral pharyngeal wall displacement was found to be reduced in the 22q11.2 deletion syndrome group (U = 29.50, p =.001, r =.63). However, measures of velar displacement were not observed to differ between groups. Similarly, lateral pharyngeal wall motion pattern distributions were not found to differ across these two groups. Conclusions: Velopharyngeal dysfunction in patients with 22q11.2 deletion syndrome showed differences in dynamic velopharyngeal function when compared to non-syndromic cleft palate patients. The current findings provide initial insights into the unique aspects of velopharyngeal dysfunction for patients with 22q11.2 deletion syndrome. These findings may guide further efforts directed toward understanding the dynamic velopharyngeal characteristics of this population and potentially optimize surgical management and functional outcomes

Bioflavonoid luteolin prevents sFlt-1 release via HIF-1α inhibition in cultured human placenta

Preeclampsia (PE) is a serious hypertensive complication of pregnancy and is a leading cause of maternal death and major contributor to maternal and perinatal morbidity, including establishment of long-term complications. The continued prevalence of PE stresses the need for identification of novel treatments which can target prohypertensive factors implicated in the disease pathophysiology, such as soluble fms-like tyrosine kinase 1 (sFlt-1). We set out to identify novel compounds to reduce placental sFlt-1 and determine whether this occurs via hypoxia-inducible factor (HIF)-1α inhibition. We utilized a commercially available library of natural compounds to assess their ability to reduce sFlt-1 release from primary human placental cytotrophoblast cells (CTBs). Human placental explants from normotensive (NT) and preeclamptic (PE) pregnancies were treated with varying concentrations of luteolin. Protein and mRNA expression of sFlt-1 and upstream mediators were evaluated using ELISA, western blot, and real-time PCR. Of the natural compounds examined, luteolin showed the most potent inhibition of sFlt-1 release, with >95% reduction compared to vehicle-treated. Luteolin significantly inhibited sFlt-1 in cultured placental explants compared to vehicle-treated in a dose- and time-dependent manner. Additionally, significant decreases in HIF-1α expression were observed in luteolin-treated explants, suggesting a mechanism for sFlt-1 downregulation. The ability of luteolin to inhibit HIF-1α may be mediated through the Akt pathway, as inhibitors to Akt and its upstream regulator phosphatidylinositol-3 kinase (PI3K) resulted in significant HIF-1α reduction. Luteolin reduces anti-angiogenic sFlt-1 through inhibition of HIF-1α, making it a novel candidate for the treatment of PE

The influence of desensitizing agent on the bond strength of various luting cements

Background: Veneer restorations either an individual or component of fixed partial prosthesis play vital role in prosthetic dentistry. This study is carried out to evaluate retentivity of cementing medium i.e commercially available desensitizing agents. Aims & Objectives: 1. To evaluate the retentive ability of different luting cements used in Fixed Prosthodontics. 2. To compare the retentive ability of different luting cements used in Fixed Prosthodontics after application of desensitizing agents. Methods & Material: Three desensitizing materials are used i.e. Gluma, Systemp and Prime desensitizer. Zinc Phosphate, Zinc Polycarboxylate and Resin Reinforce Glass Ionomer cement used in study. Teeth were mounted in the auto polymerizing acrylic resin blocks. Sixty recently extracted caries free maxillary first premolar teeth of approximately similar sizes were selected. All sixty teeth grouped in to equal four groups. Group II, III & IV coated with Gluma, Systemp and Prime desensitizers respectively and group I left uncoated. Five samples from each group cemented with three different types of cement as mentioned. Samples were incubated and tested. Results: The application of Gluma desensitizing agent increases the tensile bond strength of the cements and the application of Systemp and Prime desensitizing agent does not have any significance on the tensile bond strength of luting agents

MobilomeFINDER: web-based tools for in silico and experimental discovery of bacterial genomic islands

MobilomeFINDER (http://mml.sjtu.edu.cn/MobilomeFINDER) is an interactive online tool that facilitates bacterial genomic island or ‘mobile genome’ (mobilome) discovery; it integrates the ArrayOme and tRNAcc software packages. ArrayOme utilizes a microarray-derived comparative genomic hybridization input data set to generate ‘inferred contigs’ produced by merging adjacent genes classified as ‘present’. Collectively these ‘fragments’ represent a hypothetical ‘microarray-visualized genome (MVG)’. ArrayOme permits recognition of discordances between physical genome and MVG sizes, thereby enabling identification of strains rich in microarray-elusive novel genes. Individual tRNAcc tools facilitate automated identification of genomic islands by comparative analysis of the contents and contexts of tRNA sites and other integration hotspots in closely related sequenced genomes. Accessory tools facilitate design of hotspot-flanking primers for in silico and/or wet-science-based interrogation of cognate loci in unsequenced strains and analysis of islands for features suggestive of foreign origins; island-specific and genome-contextual features are tabulated and represented in schematic and graphical forms. To date we have used MobilomeFINDER to analyse several Enterobacteriaceae, Pseudomonas aeruginosa and Streptococcus suis genomes. MobilomeFINDER enables high-throughput island identification and characterization through increased exploitation of emerging sequence data and PCR-based profiling of unsequenced test strains; subsequent targeted yeast recombination-based capture permits full-length sequencing and detailed functional studies of novel genomic islands

Medial Prefrontal and Anterior Insular Connectivity in Early Schizophrenia and Major Depressive Disorder: A Resting Functional MRI Evaluation of Large-Scale Brain Network Models

Anomalies in the medial prefrontal cortex, anterior insulae, and large-scale brain networks associated with them have been proposed to underlie the pathophysiology of schizophrenia and major depressive disorder (MDD). In this study, we examined the connectivity of the medial prefrontal cortices and anterior insulae in 24 healthy controls, 24 patients with schizophrenia, and 24 patients with MDD early in illness with seed based resting state functional magnetic resonance imaging analysis using Statistical Probability Mapping. As hypothesized, reduced connectivity was found between the medial prefrontal cortex and the dorsal anterior cingulate cortex and other nodes associated with directed effort in patients with schizophrenia compared to controls while patients with MDD had reduced connectivity between the medial prefrontal cortex and ventral prefrontal emotional encoding regions compared to controls. Reduced connectivity was found between the anterior insulae and the medial prefrontal cortex in schizophrenia compared to controls, but contrary to some models emotion processing regions failed to demonstrate increased connectivity with the medial prefrontal cortex in MDD compared to controls. Although, not statistically significant after correction for multiple comparisons, patients with schizophrenia tended to demonstrate decreased connectivity between basal ganglia-thalamocortical regions and the medial prefrontal cortex compared to patients with MDD, which might be expected as these regions effect action. Results were interpreted to support anomalies in nodes associated with directed effort in schizophrenia and nodes associated with emotional encoding network in MDD compared to healthy controls