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The performance of a new film cooling scheme has been numerically investigated. The scheme consists of a blade-type swirl generator that adds a swirl pattern to the injected coolant stream. Reynolds-Averaged Navier-Stokes equations along with a realizable k-ε turbulence model have been solved. The film cooling effectiveness over a flat plate downstream the coolant injection hole was determined for different generator geometric parameters and operating conditions. These parameters are the generator length to the injection hole diameter ratio, twist angle, and location from the hole inlet. The operating conditions are four different blowing ratios, constant density ratio of 2.0, mainstream turbulence intensity of 5% and Reynolds number of 80,000 based on the hole diameter and mainstream velocity. The results showed an enhancement in the laterally averaged cooling effectiveness accompanied by enriched jet spreading downstream the in-hole swirl generator, while the area-averaged cooling effectiveness increased by 74%, 293%, and 805% at blowing ratios 1.0, 1.5 and 2.0, respectively, compared to that for a scheme without swirl generator. Such enhancement is attributed to the vortical structure generated and hence the interaction with the mainstream. Optimization was conducted on obtained results to determine the optimal swirl generator geometric parameters. [ABSTRACT FROM AUTHOR]

The studied materials contain two different types of intermediates (SrO and Gd2O3) which can enhance the biocompatible behavior of the material. Melt annealing was used to prepare new bioactive borate glasses with a composition of 42.7B2O3-(23.5−x) CaO-26Na2O-5SrO-2.8P2O5-xGd2O3 with 0 ≤ x ≤ 0.5 mol %. A heat-treated procedure was used to produce the glass–ceramic derivatives, which were characterized using various measurement techniques. Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) pattern, and scanning electron microscopy (SEM) were used to test the prepared glass and its glass–ceramic derivatives before and after soaking in testing solutions (K2HPO4) and simulated body fluid (SBF) at 37 °C for different time intervals. After immersion in the K2HPO4 and SBF solutions, two FTIR absorbed bands were clearly formed at roughly 567 and 607 cm−1, suggesting the formation of the hydroxyapatite layer (HA). The major well-formed crystalline phases are calcium phosphate (Ca3(PO4)2) and calcium borate (CaB2O4) bioactive phases. These findings suggest that all prepared glass samples have good bioactivity, making them ideal for a variety of biological applications. [ABSTRACT FROM AUTHOR]

Dolomite minerals were collected from the Red Sea Mountains around the Sokhna region. The rock was collected, rinsed, and crushed using a ball mailing machine and used without further purification. The dolomite sample was characterized using FTIR, XRD, SEM/EDAX, and mapping to ensure their composition and homogeneity. The obtained data reveal that the presence of a homogenous crystalline structure of CaMg(CO3)2. The characterized rock was used as a catalyst in the eco-friendly synthesis of bis-indolyl methane derivatives by reacting two moles of unsubstituted indole and various aromatic aldehydes in the presence of Red-Sea Dolomite mineral as an economical, recyclable, easily obtained, and nontoxic catalyst under solvent-free conditions. The molecular docking study explained that the bis-indolyl methane can be considered as a small molecule stimulator of HIV-1 frameshifting and inhibitor of viral replication. [ABSTRACT FROM AUTHOR]

An optical image security encryption technique based on randomized pixel positions, amplitude modulation and phase modulation for an image encryption system that is working through a spatial light modulator and nonlinear semiconductor lasers has been proposed. Chaotic injection from a master laser generator (ML), three slave lasers (SL1, SL2 and SL3) through an optical processor can produce chaotic effects on optical image signals. During the confusion process the chaotic image signal of SL1 can be used to generate horizontal flipping of the image signal to randomize pixel positions. SL2, through the optical processor, separates the image signal to columns and rows, after which it divides pixel values of even rows by odd rows and odd rows by even rows. SL3, through the optical processor, divides pixel values of an even column by odd column and odd column by even column. The output of SL3 passes through lens1 to transform the signal into frequency domain and uses four spatial light modulators (SLM1, SLM2, SLM3 and SLM4) to apply quadrant random phase modulation. It then passes resulting signal into lens2 to revert the signal in time domain and extracts it in charge-coupled device CCD image sensor. Extensive analysis of the proposed encryption system is carried out and displays good results in quality metrics in comparison to other encryption techniques. The analysis demonstrates the valuable high security and immunity to noise of the proposed image encryption technique. [ABSTRACT FROM AUTHOR]

Abstract Background The ongoing global pandemic of coronavirus disease 2019 (COVID-19) may cause, in addition to lung disease, a wide spectrum of non-respiratory complications. Among these are thromboembolic complications. The theories that explain the mechanism of thromboembolic complications of COVID-19 are accumulating rapidly, and in addition to the role of imaging for assessment of COVID-19 pneumonia, CT may be useful for identification of these complications, such as pulmonary embolism, ischaemic stroke, mesenteric ischaemia, and acro-ischaemia. Results Thromboembolic manifestations were diagnosed in 10% of our patients (124 patients out of the total 1245 COVID-19 patients); 56 patients (45.2%) presented with pulmonary embolism, 32 patients (25.8%) presented with cerebrovascular manifestations, 17 patients (13.7%) presented with limb affection, and 19 patients (15.3%) presented with gastrointestinal thromboembolic complications. Most of our patients had significant comorbidities; diabetes was found in 72 patients (58%), dyslipidemia in 72 patients (58%), smoking in 71 patients (57.3%), hypertension in 63 patients (50.8%), and morbid obesity in 40 patients (32.2%). Thromboembolic events were diagnosed on admission in 41 patients (33.1%), during the first week in 61 patients (49.2%), and after the first week in 22 patients (17.7%). Conclusions The incidence of thromboembolic complications in COVID-19 patients is relatively high resulting in a multisystem thrombotic disease. In addition to the crucial role of imaging for assessment of COVID-19 pneumonia, CT is important for assessment of the thromboembolic complications, such as pulmonary embolism, ischaemic stroke, mesenteric ischaemia, and peripheral ischaemia, especially in patients with elevated d-dimer levels and those with sudden clinical deterioration.

Abstract Background Coronavirus (COVID-19) pneumonia emerged in Wuhan, China, in December 2019. It was highly contagious spreading all over the world, with a rapid increase in the number of deaths. The reported cases have reached more than 14 million with more than 600,000 deaths around the world. So, the pandemic of COVID-19 became a surpassing healthcare crisis with an intensive load on the healthcare resources. In this study, the aim was to differentiate COVID-19 pneumonia from its mimickers as atypical infection, interstitial lung diseases, and eosinophilic lung diseases based on CT, clinical, and laboratory findings. Results This retrospective study included 260 patients, of which 220 were confirmed as COVID-19 positive by two repeated RT-PCR test and 40 were classified as non-COVID by two repeated negative RT-PCR test or identification of other pathogens, other relevant histories, or clinical findings. In this study, 158 patients were male (60.7 %) and 102 patients were female (39.3%). There was 60.9% of the COVID-19 group were male and 39.1% were female. Patients in the non-COVID group were significantly older (the mean age was 46.4) than those in the confirmed COVID-19 group (35.2y). In the COVID-19 group, there was exposure history to positive cases in 84.1% while positive exposure history was 20% in the non-COVID group. Conclusion The spectrum of CT imaging findings in COVID-19 pneumonia is wide that could be contributed by many other diseases making the interpretation of chest CTs nowadays challenging to differentiate between different diseases having the same signs and act as deceiving simulators in the era of COVID-19.