Modeling and Simulations of Moving Droplets in Relation to SARS-CoV-19 Generated by Respiratory System

Contemporary issues such as epidemics and the prevalence of infectious indicate that there is a pressing need to better understand the dynamics of transmission in air and facemasks. Consistent with previous literature, coronavirus disease (COVID-2019) is caused by the novel virus SARS-CoV-2. Coronavirus adds a new element to fluid fragmentation leading to respiratory droplets and which are transmitted via air during coughing, sneezing and talking. The behavior of virus-laden droplets of saliva particles arising from a human cough is described by Navier–Stokes equation for turbulent flow. The predicted velocity and pressure for droplets flow with time are presented. Hence, wall-normal profiles of velocity, pressure and concentration are obtained from boundary-layer approximations and the Navier–Stokes equations are solved on a two-dimensional shell mesh. The purpose of this study is to provide a perspective on the role of masks in the COVID-19 pandemic with an emphasis on the mechanism of droplet leakage and the droplet dispersion in this masks medical non-pharmaceutical intervention.

Chemical reactivities and molecular docking studies of parthenolide with the main protease of HEP-G2 and SARS-CoV-2

We have used bioinformatics to identify drugs for the treatment of COVID-19, using drugs already being tested for the treatment as benchmarks like Remdesivir and Chloroquine. Our findings provide further support for drugs that are already being explored as therapeutic agents for the treatment of COVID-19 and identify promising new targets that merit further investigation. In addition, the epoxidation of Parthenolide 1 using peracids, has been scrutinized within the MEDT at the B3LYP/6-311(d,p) computational level. DFT results showed a high chemoselectivity on the double bond C₃[bond, double bond]C₄, in full agreement with the experimental outcomes. ELF analysis demonstrated that epoxidation reaction took place through a one-step mechanism, in which the formation of the two new C-O single bonds is somewhat asynchronous.

Corrosion inhibition performance of azelaic acid dihydrazide: a molecular dynamics and Monte Carlo simulation study

The adsorption of azelaic acid dihydrazide as an environmentally friendly mild steel corrosion inhibitor on the iron surface was modeled in this study. We used density functional theory (DFT) calculations and Monte Carlo (MC) and molecular dynamics (MD) simulations to illustrate the interactions engaged. The interaction of the azelaic acid derivatives with iron metal (Fe) was examined by DFT as a typical example of a corrosion prevention mechanism after the optimized molecular structures of these molecules were investigated. Structures, binding energies, Fikui's charge indicator, electron transfer, and chemical potential are all discussed. The presence of significant binding between the inhibitor and Fe metal is supported by analysis of the resultant complex. Then, in an acidic solution comprising 491 H₂O, nine chlorine ion Cl^-, and nine hydronium ion H₃O⁺, molecular dynamics and Monte Carlo (MC) simulation were used to model the adsorption of azelaic acid dihydrazide on the iron Fe (110) surface. In addition, radial distribution function (RDF) and interaction energy (Ei) were evaluated in this work to further our understanding of interactions between azelaic acid dihydrazide and iron surfaces. Furthermore, we discovered that our inhibitors have an excellent ability to slow down the movement of corrosive particles in law temperature and thus to inhibit the metallic substrate against corrosive electrolyte, based on the temperature impact investigation. The result of density functional theory and Monte Carlo and molecular dynamics descriptors obtained were in good agreement with the experimental result.

United Arab Emirates National Newborn Screening Programme:an evaluation 1998-2000

To evaluate the United Arab Emirate National Newborn Screening Programme we compared coverage, timeliness of programme indicators [age at sampling, recall and treatment initiation, timing of specimen delivery and laboratory results] and specimen quality with international st and ards. Recall rate, sensitivity, specificity, positive predictive values and relative incidence rates for phenylketonuria [PKU] and congenital hypothyroidism [CH] were calculated. Investigations for hypothyroidism included thyroid function studies [T3, T4, fT4 and TSH], technetium-99m thyroid scan when possible and thyroglobulin and thyroid antibodies when indicated. PKU investigations included plasma amino acids and measurement of biopterin defects. In the 6 years before December 2000, 138, 718 neonates were screened. Relative incidences for CH and for classic PKU were 1: 1570 and 1: 20, 050 respectively

A Review of Mechano-Biochemical Models for Testing Composite Restorations

Due to the severe mechano-biochemical conditions in the oral cavity, many dental restorations will degrade and eventually fail. For teeth restored with resin composite, the major modes of failure are secondary caries and fracture of the tooth or restoration. While clinical studies can answer some of the more practical questions, such as the rate of failure, fundamental understanding on the failure mechanism can be obtained from laboratory studies using simplified models more effectively. Reviewed in this article are the 4 main types of models used to study the degradation of resin-composite restorations, namely, animal, human in vivo or in situ, in vitro biofilm, and in vitro chemical models. The characteristics, advantages, and disadvantages of these models are discussed and compared. The tooth-restoration interface is widely considered the weakest link in a resin composite restoration. To account for the different types of degradation that can occur (i.e., demineralization, resin hydrolysis, and collagen degradation), enzymes such as esterase and collagenase found in the oral environment are used, in addition to acids, to form biochemical models to test resin-composite restorations in conjunction with mechanical loading. Furthermore, laboratory tests are usually performed in an accelerated manner to save time. It is argued that, for an accelerated multicomponent model to be representative and predictive in terms of both the mode and the speed of degradation, the individual components must be synchronized in their rates of action and be calibrated with clinical data. The process of calibrating the in vitro models against clinical data is briefly described. To achieve representative and predictive in vitro models, more comparative studies of in vivo and in vitro models are required to calibrate the laboratory studies.

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

BACKGROUND

Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality.

METHODS

We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis.

FINDINGS

We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36-39) and median bodyweight at presentation was 2·8 kg (2·3-3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88-4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59-2·79], p<0·0001), sepsis at presentation (1·20 [1·04-1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4-5 vs ASA 1-2, 1·82 [1·40-2·35], p<0·0001; ASA 3 vs ASA 1-2, 1·58, [1·30-1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02-1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41-2·71], p=0·0001; parenteral nutrition 1·35, [1·05-1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47-0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50-0·86], p=0·0024) or percutaneous central line (0·69 [0·48-1·00], p=0·049) were associated with lower mortality.

INTERPRETATION

Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030.

FUNDING

Wellcome Trust.

Characterization of Antigen Escape Mutations in Chronic HBV-Infected Patients in Upper Egypt

Background

Mutations within the “a” determinant region (position 124–147) that is present in the major hydrophilic region (MHR, position 99–160) of the hepatitis B surface antigen (HBsAg) are associated with vaccine-escape, lack of diagnosis, and failure to hepatitis B immunoglobulin (HBIG) therapy. Data regarding the amino acid changes of “a” determinant region of HBsAg are limited in Egypt. The prevalence and mutations in this region among chronic HBV (CHB)-infected patients in Upper Egypt are not known.

Material and Methods

Blood samples were collected from HBsAg-positive CHB-infected patients (n=123) admitted to Assiut University Hospitals. Serum samples were screened for HBsAg, HBeAg, anti-HBs and anti-HBe antibodies using commercially available ELISA kits. Viral load was determined by qPCR. In addition, mutational analysis was carried out targeting the HBV surface gene to determine the HBV genotype and vaccine escape mutations.

Results

Sequencing analysis of HBV DNA revealed that genotype D is the major circulating type (81.3%), followed by genotype E (18.7%). Analysis of the HBV genome revealed that 103/123 (83.7%) patients showed wild-type sequences and 20/123 (16.3%) showed mutations in the HBsAg gene. Mutation in seventeen patients (17/20, 85%) showed only one mutation, and three patients showed two mutations (3/20, 15%) in the “a” determinant region. The observed mutations were T115S (3/20, 15%), P120T/S (3/20, 15%), T126S (1/20, 5%), Q129R (2/20, 10%), M133T (2/20, 10%), S143L (5/20, 25%), D144E/A (3/20, 15%), and G145R/A (4/20, 20%). Mutations in the “a” determinant region were detected in genotype D isolates only.

Conclusion

We described for the first time the prevalence and characterization of vaccine escape mutants in CHB patients in Upper Egypt. Mutational analysis of the “a” determinant region revealed the presence of a wide spectrum of mutants in the circulating HBV isolates that could be a potential threat to HBV diagnosis, therapy success, and HBV vaccination program in Upper Egypt.

In a search for potential drug candidates for combating COVID-19: computational study revealed salvianolic acid B as a potential therapeutic targeting 3CLpro and spike proteins

The global prevalence of COVID-19 disease and the overwhelming increase in death toll urge scientists to discover new effective drugs. Although the drug discovery process is a challenging and time-consuming, fortunately, the plant kingdom was found to have many active therapeutics possessing broad-spectrum antiviral activity including those candidates active against severe acute respiratory syndrome coronaviruses (SARS-CoV). Herein, nine traditional Chinese medicinal plant constituents from different origins (Glycyrrhizin 1, Lycorine 2, Puerarin 3, Daidzein 4, Daidzin 5, Salvianolic acid B 6, Dihydrotanshinone I 7, Tanshinone I 8, Tanshinone IIa 9) previously reported to exhibit antiviral activity against SARS-CoV were virtually screened in silico (molecular docking) as potential inhibitors of SARS-CoV-2 target proteins. The tested medicinal plant compounds were in silico screened for their activity against two key SARS-CoV-2 target proteins; 3CLpro, and Spike binding-domain proteins. Among the tested medicinal plant compounds, Salvianolic acid B 6 (Sal-B) showed promising binding affinities against the two specified SARS-CoV-2 target proteins compared to the reference standards used. Hence molecular dynamics simulations followed by calculating the free-binding energy were carried out for Sal-B providing information on its affinity, stability, and thermodynamic behavior within the two SARS-CoV-2 target proteins as well as key ligand-protein binding aspects. Besides, the quantum mechanical calculations showed that Sal-B can adopt different conformations due to the existence of various rotatable bonds. Therefore, the enhanced antiviral activity of Sal-B among other studied compounds can be also attributed to the structural flexibility of Sal-B. Our study gives an explanation of the structure activity relationship required for targeting SARS-CoV-2 3CLpro and Spike proteins and also facilitates the future design and synthesis of new potential drugs exhibiting better affinity and specificity. Besides, an ADME study was carried out on screened compounds and reference controls revealing their pharmacokinetics properties.Communicated by Ramaswamy H. Sarma.

Exosome-mediated radiosensitizing effect on neighboring cancer cells via increase in intracellular levels of reactive oxygen species

The precise mechanism of intercellular communication between cancer cells following radiation exposure is unclear. Exosomes are membrane‑enclosed small vesicles comprising lipid bilayers and are mediators of intercellular communication that transport a variety of intracellular components, including microRNAs (miRNAs or miRs). The present study aimed to identify novel roles of exosomes released from irradiated cells to neighboring cancer cells. In order to confirm the presence of exosomes in the human pancreatic cancer cell line MIAPaCa‑2, ultracentrifugation was performed followed by transmission electron microscopy and nanoparticle tracking analysis (NanoSight) using the exosome‑specific surface markers CD9 and CD63. Subsequent endocytosis of exosomes was confirmed by fluorescent microscopy. Cell survival following irradiation and the addition of exosomes was evaluated by colony forming assay. Expression levels of miRNAs in exosomes were then quantified by microarray analysis, while protein expression levels of Cu/Zn‑ and Mn‑superoxide dismutase (SOD1 and 2, respectively) enzymes in MIAPaCa‑2 cells were evaluated by western blotting. Results showed that the uptake of irradiated exosomes was significantly higher than that of non‑irradiated exosomes. Notably, irradiated exosomes induced higher intracellular levels of reactive oxygen species (ROS) and a higher frequency of DNA damage in MIAPaCa‑2 cells, as determined by fluorescent microscopy and immunocytochemistry, respectively. Moreover, six up‑ and five downregulated miRNAs were identified in 5 and 8 Gy‑irradiated cells using miRNA microarray analyses. Further analysis using miRNA mimics and reverse transcription‑quantitative PCR identified miR‑6823‑5p as a potential candidate to inhibit SOD1, leading to increased intracellular ROS levels and DNA damage. To the best of our knowledge, the present study is the first to demonstrate that irradiated exosomes enhance the radiation effect via increasing intracellular ROS levels in cancer cells. This contributes to improved understanding of the bystander effect of neighboring cancer cells.

Alterations in skin microbiome mediated by radiotherapy and their potential roles in the prognosis of radiotherapy-induced dermatitis: a pilot study

Radiotherapy-induced dermatitis (RID) is an inflammatory cutaneous disorder that is acquired as an adverse effect of undergoing radiotherapy. Skin microbiome dysbiosis has been linked to the outcomes of several dermatological diseases. To explore the skin microbiota of RID and deduce their underlying impact on the outcome of RID, cutaneous microbiomes of 78 RID patients and 20 healthy subjects were characterized by sequencing V1-V3 regions of 16S rRNA gene. In total, a significantly apparent reduction in bacterial diversity was detected in microbiomes of RID in comparison to controls. Overall, the raised Proteobacteria/ Firmicutes ratio was significantly linked to delayed recovery or tendency toward the permanence of RID (Kruskal Wallis: P = 2.66 × 10^–4). Moreover, applying enterotyping on our samples stratified microbiomes into A, B, and C dermotypes. Dermotype C included overrepresentation of Pseudomonas, Staphylococcus and Stenotrophomonas and was markedly associated with delayed healing of RID. Strikingly, coexistence of diabetes mellitus and RID was remarkably correlated with a significant overrepresentation of Klebsiella or Pseudomonas and Staphylococcus. Metabolic abilities of skin microbiome could support their potential roles in the pathogenesis of RID. Cutaneous microbiome profiling at the early stages of RID could be indicative of prospective clinical outcomes and maybe a helpful guide for personalized therapy.

Theoretical Aspect of Physical Phenomena in Inorganic Photovoltaic Cells. Electrical Modeling and Numerical Simulation

This work is based on the development of a theoretical model describing the drift and diffusion transport of photogenerated charge carriers and the impact of space charge on this transport in relation to the different physical phenomena characterizing the photovoltaic conversion in an inorganic silicon-based cell. In a second step, we used a numerical solution of the transport differential equations based on the Runge-Kutta algorithm in the framework of the finite difference method, This led us to an electrical model of the photovoltaic cell and of the photo-generated currents by RLC circuit equipped with a diode modeling the direction of electron and hole transport and allowed us to study the relations between the optical and electrical properties of the cell, as well as the influence of the different concentrations of impurities used for the n-type and p-type doping of the silicon on the properties of absorption of the light photons, the spectral response as well as the conductivity, the open-circuit potential and the short-circuit current.

Onsite Versus Remote Working: The Impact on Satisfaction, Productivity, and Performance of Medical Call Center Workers

Job satisfaction is determined as the measure to know the individuals’ feelings toward their work. The working conditions that can affect satisfaction and performance of the call center agents have received particular concern. This study aimed to determine the role of remote call center working on agents’ satisfaction compared to onsite workers. A cross-section study was conducted between December 2020 and April 2021 that include 124 agents working in a governmental medical call center in Saudi Arabia. Each agent was receiving a questionnaire that investigates his/her satisfaction with the job nature, supervisor support, job autonomy, job productivity, and performance. Seventy-seven physicians working onsite were compared to forty-seven physicians remotely working in the medical call center. The mean age of the physicians included was 43.17 ± 8.4 years, and most of them were male (>70%), married (>85%), and family medicine specialists (>50%). The mean years of experience in the medical field of the physicians included was 16.87 ± 8.07 years, and the mean years of experience in the medical call center was 1.44 ± .97 years. Onsite agents were more satisfied concerning job nature, supervisor support, productivity, and performance compared to remote agents (70.82 vs 53.47%, 63.38 vs 55.05%, and 66.51 vs 56.03%, respectively). However, onsite agents were less satisfied regarding job autonomy than remote physicians (46.81 vs 53.19%, P-value = .128). Overall, general satisfaction was more seen in physicians working onsite as opposed to remote workers in the medical call center in Saudi Arabia (64.90 vs 54.25%, P-value < .01).

Repeated COVID-19 infection in recipients of post-living donor liver transplantation: Two real-life cases

COVID-19 is an emerging pandemic. The course and management of the disease in the liver transplant setting may be difficult due to a long-standing immunosuppressive state. In Egypt, the only available option is living donor liver transplantation (LDLT). In our centre, we have transplanted 440 livers since 2008. In this study, we report a single-centre experience with COVID-19 infection in long-term liver transplant recipients. A total of 25 recipients (5.7 %) had COVID-19 infections since March 2020. Among these recipients, two developed COVID-19 infections twice, approximately three and two months apart, respectively.

Traumatic brain injury probability of survival assessment in adults using iterative random comparison classification

Trauma brain injury (TBI) is the most common cause of death and disability in young adults. A method to determine the probability of survival (Ps) in trauma called iterative random comparison classification (IRCC) was developed and its performance was evaluated in TBI. IRCC operates by iteratively comparing the test case with randomly chosen subgroups of cases from a database of known outcomes (survivors and not survivors) and determines the overall percentage match. The performance of IRCC to determine Ps in TBI was compared with two existing methods. One was Ps14 that uses regression and the other was predictive statistical diagnosis (PSD) that is based on Bayesian statistic. The TBI database contained 4124 adult cases (mean age 67.9 years, standard deviation 21.6) of which 3553 (86.2%) were survivors and 571 (13.8%) were not survivors. IRCC determined Ps for the survivors and not survivors with an accuracy of 79.0 and 71.4%, respectively, while the corresponding values for Ps14 were 97.4% (survivors) and 40.2% (not survivors) and for PSD were 90.8% (survivors) and 50% (not survivors). IRCC could be valuable for determining Ps in TBI and with a suitable database in other traumas.

Modified R.E.N.A.L nephrometry score for predicting the outcome following partial nephrectomy

Background

It was difficult to compare the outcome of partial nephrectomy among different studies due to the absence of standardized description of different renal masses. This problem led to the development of nephrometry scoring systems. R.E.N.A.L. is among the commonest nephrometry scoring systems; however, some studies failed to find any relation between R.E.N.A.L. with perioperative outcome. We evaluated our designed newly modified nephrometry score in prediction of outcome following partial nephrectomy and compared its predictability versus original R.E.N.A.L.

Methods

Fifty-one patients with cT1-2N0M0 renal masses amenable for partial nephrectomy were included prospectively. Different perioperative outcome variables were compared according to complexity level in R.E.N.A.L. and the newly modified nephrometry score.

Results

Clinical staging was T1a (21.6%), T1b (49%), T2a (25.5%), T2b (3.9%). Median R.E.N.A.L. was 9 (4–12). Hilar position and intrarenal pelvis were detected in 19.6% and 68.6%. Low, moderate and high complexity masses were found in 21.6%, 39.2% and 39.2%. Complications and rate of conversion to radical nephrectomy were 17 (33.3%) and 4 (7.8%). The only significantly affected variable (p = 0.039) by R.E.N.A.L. was rate of secondary intervention, but it was higher in low than in high complexity level. In the newly modified nephrometry score, complications (p = 0.037) and rate of positive surgical margin (p = 0.049) were significantly higher with increased complexity level. Although other variables (pelvi-calyceal system entry, operative time, blood loss, hemoglobin loss, blood transfusion and conversion to radical nephrectomy) did not show statistically significant difference according to both scores, they were better associated with the complexity level in the newly modified nephrometry score with their remarkable increase in the high when compared to the low complexity level.

Conclusions

The newly modified nephrometry score was associated with better prediction of outcome of partial nephrectomy when compared to R.E.N.A.L.

Biogenic silver nanoparticles induce apoptosis in Ehrlich ascites carcinoma

Introduction: Plant-mediated synthesis of silver nanoparticles (AgNPs) is accounted as an ecofriendly process. The present study was conducted to estimate the potency of biogenic AgNPs against Ehrlich ascites carcinoma (EAC) cells in vitro and EAC-bearing mice in vivo. Methods: AgNPs were prepared using mango leaves extract and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscopy (TEM). Ehrlich ascites carcinoma (EAC) mouse model was established by intraperitoneal injection of 1 x 106 EAC cells. Biogenic AgNPs- alone or combined with Doxorubicin (DOX)- was administered intraperitoneally day by day for two weeks. Results: Biologically synthesized AgNPs showed a cytotoxic effect against cultured EAC cells but with less toxicity toward normal cells compared to DOX, which had strong cytotoxicity against both cells. Biogenic AgNPs alone or combined with DOX triggered the cytotoxicity against the EAC-bearing mouse model via decreasing body weight, tumor volume, and the number of viable tumor cells. The combined treatment (AgNPs-DOX) ameliorated the drastic effect induced by injection of EAC cells through improving liver and kidney functions compared to those treated with DOX alone. In addition, the combined treatment showed an elevation in the expression of Bax and caspase-3, and a reduction in the expression of Bcl-2 protein in the EAC cells. Furthermore, this combined treatment effectively arrested the cell cycle at the G0/G1 phase. Moreover, the combined treatment with AgNPs-DOX caused a significant reduction in the activity of ornithine decarboxylase (ODC). Conclusion: These findings suggest that biogenic AgNPs could be useful in developing a potent combination therapy against different types of cancers.

MEDT study of the 1,3-DC reaction of diazomethane with Psilostachyin and investigation about the interactions of some pyrazoline derivatives with protease (Mpro) of nCoV-2

The molecular electronic density theory (MEDT) was invested to elucidate the chemo-, regio- and stereo-selectivity of the 1,3-dipolar cycloaddition between Diazomethane (DZM) and Psilostachyin (PSH). The DFT method at B3LYP/6-31 + G (d,p) level of theory was used. Reactivity indices, transition structures theory, IGM and ELF analysis were employed to reveal the mechanism of the reaction. The addition of DZM to PSH takes place through a one-step mechanism and an asynchronous transition states. Eight possible addition channels of reaction were investigated (addition of C (sp2) to Diazomethane at C4, C5, C6 or C7). The addition of C (sp2) at C5 leading to P1 product is the preferred channel. The addition of ether does not affect the chemo-, regio- and stereo-selectivity of the reaction. Analysis of transfer of charges along the IRC path associated with the P1 product shows a polar character for the studied reaction. We have also used the noncovalent interaction (NCI) which is very helpful to reveal the most favored addition channel of the reaction, by analyzing the weak interactions in different TSs. Finally, we investigate about the potential of inhibition of some pyrazoline compounds against COVID-19-M^pro by performing a molecular docking calculations.

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The 1,3-DC reaction between Diazomethane and Psilostachyin has been investigated by MEDT.

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The asynchronicity of TSs has been revealed by IGM and Wiberg indices.

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The electronic description of mechanism of reaction has been performed by ELF analysis.

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The NCI analysis allow a deep description of weak interactions.

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The pyrazolines products possess a potential effect against COVID-19.

Compressively Stressed Silicon Nanoclusters as an Antifracture Mechanism for High-Performance Lithium-Ion Battery Anodes

Silicon has been considered a good candidate for replacing the commonly used carbon anodes for lithium-ion batteries (LIBs) due to its high specific capacity, which can be up to 11 times higher than that of carbon. However, the desirable advantage that silicon brings to battery performance is currently overshadowed by its stress-induced performance loss and high electronic resistivity. The induced stress arises from two sources, namely, the deposition process (i.e., residual stress) during fabrication and the volume expansion (i.e., mechanical stress) associated with the lithiation/delithiation process. Of the two, residual stress has largely been ignored, underestimated, or considered to have a negligible effect without any rigorous evidence being put forward. In this contribution, we produced silicon thin films having a wide range of residual stress and resistivity using a physical vapor deposition technique, magnetron sputtering. Three pairs of silicon thin-film anodes were utilized to study the effect of residual stress on the electrochemical and cyclability performance as anodes for LIBs. Each set consisted of a pair of films having essentially the same resistivity, density, thickness, and oxidation amount but distinctly different residual stresses. The comparison was evaluated by conducting charge/discharge cycling and cyclic voltammetry (CV) experiments. In contrast to the fixed belief within the literature, higher compressive residual-stress films showed better electrochemical and cycle performance compared to lower residual-stress films. The results, herein, present an informed understanding of the role that residual stress plays, which will help researchers improve the development of silicon-based thin-film anodes.

Elucidation of gastrointestinal dysfunction in response to irradiation using metabolomics

Gastrointestinal toxicity is frequently observed secondary to accidental or therapeutic radiation exposure. However, the variation in the intestinal metabolites after abdominal radiation exposure remains ambiguous. In the present study, C57BL/6 mice were exposed to 0, 2, and 20 Gy irradiation dose. The Head and chest of each mouse were covered with a lead shield before x-ray irradiation. 24 h post-irradiation treatment, intestinal tissue of each mouse was excised and prepared for metabolites measurement using gas chromatography-mass spectrometry (GC-MS). Our comprehensive analysis of metabolites in the intestinal tissues detected 44 metabolites after irradiation, including amino acids, carbohydrates, organic acids, and sugars. Amino acid levels in the intestinal tissue gradually rose, dependent on the radiation dose, perhaps as an indication of oxidative stress. Our findings raise the possibility that amino acid metabolism may be a potential target for the development of treatments to alleviate or mitigate the harmful effects of oxidative stress-related gastrointestinal toxicity due to radiation exposure.

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Gastrointestinal damage frequently results from radiation exposure.

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We analyzed the metabolic profile after local irradiation to the intestine.

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Amino acid levels in the intestinal tissue rose dependent on the radiation dose.

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Amino acid metabolism may be a good target for future therapies.