Polymorph driven diversification of photosalient responses in a zinc(II) coordination complex.

A novel crystallographic form of a Zn(II) coordination complex [Zn(4-ohbz)2(4-nvp)2] (1-Form-III) (H4-ohbz = 4-hydroxybenzoic acid and 4-nvp = (E)-4-(1-naphthylvinyl)pyridine), undergoes a solid-state photochemical [2+2] cycloaddition reaction accompanied by a moderate photosalient effect, whereby single-crystals show cracking and splitting. This UV-induced cycloaddition accompanies a single-crystal to single-crystal transformation, allowing for continuous monitoring of the unit cell parameters. The new polymorph represents an intermediate form of the two previously reported crystallographic forms of [Zn(4-ohbz)2(4-nvp)2], and provides novel insight into moderating the magnitude of photosalient responses across polymorphic materials.

Takotsubo syndrome after concomitant surgical ablation for the treatment of atrial fibrillation in patients undergoing minimally invasive mitral valve surgery: A clinical case and review.

INTRODUCTION AND IMPORTANCE: Takotsubo syndrome (TTS) is a reversible form of acute heart failure often triggered by physical or emotional stressors. Minimally invasive mitral valve surgery (MIMVS) has become a prevalent approach for treating mitral valve pathologies, yet its association with TTS remains underexplored. CASE PRESENTATION: We present the case of a female patient undergoing MIMVS with concomitant Maze ablation, who developed TTS postoperatively. Despite a normal coronary angiogram, transient coronary spasm due to an imbalance in autonomic nervous activity was considered. The patient exhibited preoperative risk factors including sequelae of cerebral infarction. CLINICAL DISCUSSION: Female patients undergoing MIMVS with preoperative risk factors such as cerebral infarction sequelae may be at increased risk of developing TTS postoperatively. CONCLUSION: The InterTAK Diagnostic score, in conjunction with the International Expert Consensus Document on Takotsubo Syndrome, aids in promptly diagnosing TTS and differentiating it from acute coronary syndrome. Further research is warranted to elucidate the relationship between MIMVS and TTS.

Concomitant tricuspid valve regurgitation repair in patients with minimally invasive mitral valve surgery: a single-centre experience in Vietnam.

Background: This study aims to present the early and mid-term outcomes of combining minimally invasive mitral valve surgery (MIMVS) with tricuspid valve repair (TVR) at the authors' centre. Methods: From January 2017 to March 2022, our centre treated a total of 67 patients with both MIMVS and TVR. Among these patients, 41 were women (61.2%), and 26 were men (38.8%). The average Euro SCORE II was 2.67±1.54%, and the patients had an average follow-up period of 25.45±16.2 months. Results: Pre-discharge echocardiography revealed no or mild TR in 82.8% of cases. The overall 30-day mortality rate was 4.5%, with 3 deaths. Five-year survival was 94.5%±3.2%. In patients with mild or moderate preoperative tricuspid regurgitation (TR), the 5-year survival rate was 95.7%±4.3%, while for those with severe TR, it was 93.7%±4.5% (P=0.947). Conclusions: The authors' 5-year experience demonstrates that the combination of MIMVS and TVR can be routinely performed with favourable perioperative and postoperative outcomes in patients undergoing non-high-risk surgery. Additionally, there is no significant difference in five-year survival between the severe TR and mild to moderate TR groups preoperatively.

Pregnant women with chronic hepatitis B virus infection at the assessment of tenofovir disoproxil fumarate prescription: Baseline characteristics of a prospective cohort study in Vietnam.

Objectives: We aimed to determine epidemiological characteristics and serologic markers among chronically hepatitis B virus (HBV)-infected pregnant women during the assessment of tenofovir disoproxil fumarate (TDF) prescription in Vietnam. Methods: We consecutively recruited 375 pregnant women with chronic HBV (cHBV) infection at week 25±2 of pregnancy, at which time they were assessed for TDF use as pre-prophylaxis and/or pre-treatment at the Hospital for Tropical Diseases in southern Vietnam during December 2019-April 2021. Demographic characteristics, serological biomarkers, and prenatal liver ultrasounds were obtained through interviews and reviews of medical records. Results: The median age of pregnant women was 29 years (interquartile range: 26-32). More than half of pregnant women (208/375; 55.5%) started TDF for prevention of mother-to-child transmission of HBV and/or treatment of chronic hepatitis B (CHB). Among the pregnant women initiating TDF, 96.1% (198/206) tested positive for hepatitis B e antigen, and 21.6% (45/208) had quantitative hepatitis B surface antigen (qHBsAg) ≤104 IU/mL. A relatively strong correlation between qHBsAg and HBV deoxyribonucleic acid (DNA) (r = 0.81; 95% CI: 0.76-0.85) was observed in pregnant women starting TDF. Conclusions: Our results demonstrate the high need for TDF prescription for prevention and/or treatment purposes in pregnant women with cHBV infection. Pregnant women with qHBsAg levels ≤104 IU/mL may prioritize HBV DNA testing over qHBsAg to decide on TDF prescription.

Demand for mental health support services among health professionals in Vietnam: Lesson from COVID-19 Pandemic.

BACKGROUND: This study aimed to measure the preferences for mental health support among health professionals, their willingness to support the mental health of colleagues and associated factors. METHOD: A descriptive cross-sectional study was performed from August to October 2022 within five hospitals located in Hanoi, Vietnam. A total of 244 health professionals participated in the study. Data on socio-economic status, health and COVID-19-related characteristics, Depression Anxiety Stress Scale (DASS-21); and preferences for mental health support services were collected by using a structured self-reported questionnaire. Multivariate logistic regression models were utilized to identify associated factors with the demand for mental support services. RESULTS: 13.9%, 17.1% and 8.6% reported having at least mild depression, anxiety and stress, respectively. There 13.9% did not seek any mental health support during the COVID-19 pandemic. The most common support included talking with friends (52.9%), family (50.8%), colleagues (47.6%) and using social networks/Internet (43.5%). There 31.1% had been aware of mental health services, but only 18.0% used this service at least once. Regarding preferences, 47.3% had a demand for mental support services, and the most preferred service was providing coping skills (25.9%), followed by skills to support others against mental problems (22.2%). Major sources of support included psychiatrists (34.4%), colleagues (29.1%) and family (27.9%). The main preferred channels for support included telephone/mobile phone (35.7%) and Internet (20.9%). Only 12.3% were willing to provide mental support for colleagues during the pandemic. Age, education, perceived mental health status, ever seeking any mental service, and DASS-21 depression score were associated with demand for mental support services. CONCLUSION: This study found a lack of awareness of mental health services for health professionals, as well as moderate levels of demand for this service in this population. Raising awareness and developing tailored mental health support services are important to enhancing the mental well-being of health professionals in Vietnam to prepare for the next pandemic.

Real-world analysis of afatinib as a first-line treatment for patients with advanced stage non-small-cell lung cancer with uncommon EGFR mutations: a multicenter study in Vietnam.

Background: Afatinib is indicated for advanced-stage non-small-cell lung cancer (NSCLC) with Epidermal Growth Factor Receptor (EGFR) and uncommon mutations. However, real-world studies on this topic are limited. This study aimed to evaluate afatinib as first-line therapy for locally advanced and metastatic NSCLC with uncommon EGFR mutations. Patients and methods: A retrospective study included 92 patients with advanced NSCLC with uncommon and compound EGFR mutations, treated with afatinib as first-line therapy. Patients were followed up and evaluated every 3 months or when symptoms of progressive disease arose. The endpoints were objective response rate (ORR), time-to-treatment failure (TTF), and adverse events. Results: The G719X EGFR mutation had the highest occurrence rate (53.3% for both monotherapy and the compound). By contrast, the compound mutation G719X-S768I was observed at a rate of 22.8%. The ORR was 75%, with 15.2% of patients achieving complete response. The overall median TTF was 13.8 months. Patients with the G719X EGFR mutation (single and compound) had a median TTF of 19.3 months, longer than that of patients with other mutations, who had a median TTF of 11.2 months. Patients with compound EGFR mutations (G719X and S768I) demonstrated a median TTF of 23.2 months compared to that of 12.3 months for other mutations. Tolerated doses of 20 or 30 mg achieved a longer median TTF of 17.1 months compared to 11.2 months with 40 mg. Median TTF differed between patients with and without brain metastasis, at 11.2 and 16.9 months, respectively. Rash (55.4%) and diarrhea (53.3%) were the most common adverse events, primarily grades 1 and 2. Other side effects occurred at a low rate. Conclusion: Afatinib is effective for locally advanced metastatic NSCLC with uncommon EGFR mutations. Patients with G719X, compound G719X-S768I mutations, and tolerated doses of 20 or 30 mg had a longer median TTF than those with other mutations.

Platelet-rich fibrin as an apical barrier for MTA placement in the treatment of teeth with open apices: a pilot study.

OBJECTIVE: The aim of the present pilot study was to assess the effectiveness of the platelet-rich fibrin (PRF) apical barrier for the placement of MTA for the treatment of teeth with periapical lesions and open apices. METHODS: A total of thirty teeth on twenty-eight patients with open apices and periapical periodontitis were enrolled and divided into two groups in the present pilot study. In the PRF group (fourteen teeth in thirteen patients), nonsurgical endodontic treatment was performed using PRF as an apical matrix, after which the apical plug of the MTA was created. For the non-PRF group (fourteen teeth in fourteen patients), nonsurgical endodontic therapy was performed using only the MTA for an apical plug with no further periapical intervention. Clinical findings and periapical digital radiographs were used for evaluating the healing progress after periodic follow-ups of 1, 3, 6, and 9 months. The horizontal dimension of the periapical lesion was gauged, and the changes in the dimensions were recorded each time. The Friedman test, Dunn-Bonferroni post hoc correction, and Mann-Whitney U test were used for statistical analysis, with P < 0.05 serving as the threshold for determining statistical significance. RESULTS: All patients in both groups in the present pilot study had no clinical symptoms after 1 month, with a significant reduction in the periapical lesion after periodic appointments. The lesion width of the PRF group was significantly smaller than that of the non-PRF group in the sixth and ninth month after treatment. CONCLUSIONS: PRF is a promising apical barrier matrix when combined with MTA for the treatment of teeth with open apices and periapical periodontitis. Small number of study subjects and the short time of follow-up period limit the generalizability of these results. TRIAL REGISTRATION: TCTR, TCTR20221109006. Registered 09 November 2022 - Retrospectively registered, https://www.thaiclinicaltrials.org/show/TCTR20221109006 .

A novel multi-stage enrichment workflow and comprehensive characterization for HEK293F-derived extracellular vesicles.

Extracellular vesicles (EVs) are emerging as a promising drug delivery vehicle as they are biocompatible and capable of targeted delivery. However, clinical translation of EVs remains challenging due to the lack of standardized and scalable manufacturing protocols to consistently isolate small EVs (sEVs) with both high yield and high purity. The heterogenous nature of sEVs leading to unknown composition of biocargos causes further pushback due to safety concerns. In order to address these issues, we developed a robust quality-controlled multi-stage process to produce and isolate sEVs from human embryonic kidney HEK293F cells. We then compared different 2-step and 3-step workflows for eliminating protein impurities and cell-free nucleic acids to meet acceptable limits of regulatory authorities. Our results showed that sEV production was maximized when HEK293F cells were grown at high-density stationary phase in semi-continuous culture. The novel 3-step workflow combining tangential flow filtration, sucrose-cushion ultracentrifugation and bind-elute size-exclusion chromatography outperformed other methods in sEV purity while still preserved high yield and particle integrity. The purified HEK293F-derived sEVs were thoroughly characterized for identity including sub-population analysis, content profiling including proteomics and miRNA sequencing, and demonstrated excellent preclinical safety profile in both in-vitro and in-vivo testing. Our rigorous enrichment workflow and comprehensive characterization will help advance the development of EVs, particularly HEK293F-derived sEVs, to be safe and reliable drug carriers for therapeutic applications.

A real-world cohort study of first-line afatinib in patients with EGFR-mutant advanced non-small cell lung cancer in Vietnam.

BACKGROUND: This study aimed to evaluate the efficacy and side effects of first-line afatinib treatment in a real-world setting in Vietnam. METHODS: This retrospective study was conducted across nine hospitals in Vietnam. Advanced epidermal growth factor receptor (EGFR)-mutant non-small cell lung cancer (NSCLC) patients who received afatinib as first-line therapy between April 2018 and June 2022 were included, and patient medical records were reviewed. Key outcomes were overall response rate (ORR), time-to-treatment failure (TTF), and tolerability. RESULTS: A total of 343 patients on first-line afatinib were eligible for the study. EGFR exon 19 deletion (Del19) alone was detected in 46.9% of patients, L858R mutation alone in 26.3%, and other uncommon EGFR mutations, including compound mutations, in 26.8%. Patients with brain metastases at baseline were 25.4%. Patients who received 40 mg, 30 mg, and 20 mg as starting doses of afatinib were 58.6%, 39.9%, and 1.5%, respectively. The ORR was 78.1% in the overall population, 82.6% in the Del19 mutation subgroup, 73.3% in the L858R mutation subgroup, and 75.0% in the uncommon mutation subgroup (p > 0.05). The univariate and multivariate analyses indicate that the ORR increased when the starting dose was 40 mg compared to starting doses below 40 mg (83.9% vs. 74.3%, p = 0.034). The median TTF (mTTF) was 16.7 months (CI 95%: 14.8-18.5) in all patients, with a median follow-up time of 26.2 months. The mTTF was longer in patients in the common EGFR mutation subgroup (Del19/L858R) than in those in the uncommon mutation subgroup (17.5 vs. 13.8 months, p = 0.045) and in those without versus with brain metastases at baseline (17.5 vs. 15.1 months, p = 0.049). There were no significant differences in the mTTF between subgroups based on the starting dose of 40 mg and < 40 mg (16.7 vs. 16.9 months, p > 0.05). The most common treatment-related adverse events (any grade/grade ≥ 3) were diarrhea (55.4%/3.5%), rash (51.9%/3.2%), paronychia (35.3%/5.0%), and stomatitis (22.2%/1.2%). CONCLUSIONS: Afatinib demonstrated clinical effectiveness and good tolerability in Vietnamese EGFR-mutant NSCLC patients. In our real-world setting, administering a starting dose below 40 mg might result in a reduction in ORR; however, it might not have a significant impact on TTF.

Platelet rich fibrin and MTA in the treatment of teeth with open apices.

BACKGROUND: The present study aimed to evaluate the effectiveness of using platelet-rich fibrin (PRF) as the apical matrix for the placement of MTA in nonsurgical endodontic therapy for teeth with periapical lesions and open apices. METHODS: Twelve teeth from eleven patients with periapical periodontitis and open apices were enrolled in the study. Nonsurgical endodontic therapy was performed with the PRF used as an apical barrier and the MTA manipulated as an apical plug for further thermoplasticized gutta percha in the remaining part of the root canal. Clinical signs and periapical digital radiographs were recorded and analyzed to evaluate the curing progress after periodical follow-ups of 1, 3, and 6 months. The horizontal dimension of the periapical lesion was determined, and the changes in the dimensions were recorded each time. The Friedman test was used for statistical analysis, with P < .05 serving as the threshold for determining statistical significance. RESULTS: All patients had no clinical symptoms after the first month of treatment, with a significant reduction in the periapical lesion after periodical appointments. CONCLUSIONS: PRF is an effective barrier when combined with MTA for the treatment of teeth with periapical periodontitis and open apices.

Concomitant Surgical Ablation for Treatment of Atrial Fibrillation in Patients Undergoing Minimally Invasive Mitral Valve Surgery: A Single-Center Experience in Vietnam.

BACKGROUND: This study presents the early and midterm outcomes of combining atrial fibrillation (AF) treatment with minimally invasive mitral valve surgery (MIMVS) at our center. METHODS: From January 2017 to June 2022, our center treated a total of 86 patients with both MIMVS and surgical AF ablation. The patient cohort included 62 women (72.1%) and 24 men (27.9%). The average EuroScore II was 2.64 ± 1.49%, and the patients were followed up for an average period of 46.31 ± 9.84 months. RESULTS: Postoperatively, 95.3% of patients experienced a change in sinus rhythm, and 86.2% were discharged in sinus rhythm. The hospital's mortality rate was 2.3%, with a late mortality rate of 3.5%. Survival analysis revealed an atrial fibrillation-free 5-year follow-up rate of 59.1 ± 9.1%. The 5-year survival rate was 92.7 ± 3.3%. CONCLUSION: Our 5-year experience demonstrates that the combination of MIMVS and surgical AF ablation can be routinely performed with favorable peri- and postoperative outcomes. This reflects our hospital's culture and guidance on patient selection, particularly when adopting minimally invasive approaches for multiple procedures.

Localized apelin-17 analogue-bicelle interactions as a facilitator of membrane-catalyzed receptor recognition and binding.

The apelinergic system encompasses two peptide ligand families, apelin and apela, along with the apelin receptor (AR or APJ), a class A G-protein-coupled receptor. This system has diverse physiological effects, including modulating heart contraction, vasodilation/constriction, glucose regulation, and vascular development, with involvement in a variety of pathological conditions. Apelin peptides have been previously shown to interact with and become structured upon binding to anionic micelles, consistent with a membrane-catalyzed mechanism of ligand-receptor binding. To overcome the challenges of observing nuclear magnetic resonance (NMR) spectroscopy signals of a dilute peptide in biological environments, 19F NMR spectroscopy, including diffusion ordered spectroscopy (DOSY) and saturation transfer difference (STD) experiments, was used herein to explore the membrane-interactive behaviour of apelin. NMR-optimized apelin-17 analogues with 4-trifluoromethyl-phenylalanine at various positions were designed and tested for bioactivity through ERK activation in stably-AR transfected HEK 293 T cells. Far-UV circular dichroism (CD) spectropolarimetry and 19F NMR spectroscopy were used to compare the membrane interactions of these analogues with unlabelled apelin-17 in both zwitterionic/neutral and net-negative bicelle conditions. Each analogue binds to bicelles with relatively weak affinity (i.e., in fast exchange on the NMR timescale), with preferential interactions observed at the cationic residue-rich N-terminal and mid-length regions of the peptide leaving the C-terminal end unencumbered for receptor recognition, enabling a membrane-anchored fly-casting mechanism of peptide search for the receptor. In all, this study provides further insight into the membrane-interactive behaviour of an important bioactive peptide, demonstrating interactions and biophysical behaviour that cannot be neglected in therapeutic design.

Successful surgical management of large pulmonary artery thrombosis in a patient with primary severe mitral regurgitation and complex congenital heart disease: A case report.

INTRODUCTION: Pulmonary artery thrombosis presents a rare and formidable challenge, especially in individuals with untreated complex congenital heart diseases and concurrent valvular abnormalities. PRESENTATION OF CASE: This case details a distinctive instance of pulmonary artery thrombosis in a patient with untreated congenital atrial septal defect, severe pulmonary hypertension, pulmonary aneurysm, valvular heart disease, and triple-positive antiphospholipid antibodies. Collaborative decision-making by a heart team guided the diagnostic and therapeutic processes, resulting in surgical interventions encompassing pulmonary thrombectomy, mitral and tricuspid regurgitation repair, and atrial septal defect closure. DISCUSSION: The case underscores the nuanced management of pulmonary artery thrombosis within the realm of congenital heart disease, highlighting the imperative role of a multidisciplinary approach in achieving accurate diagnoses and timely interventions. The multifaceted treatment strategy implemented further accentuates the need for continual monitoring and personalized interventions in intricate clinical scenarios. CONCLUSION: In conclusion, this case emphasizes the complexity of addressing pulmonary artery thrombosis in the context of congenital heart disease. The collaborative efforts of a multidisciplinary team proved pivotal in navigating diagnostic uncertainties and formulating a tailored treatment plan. Ongoing monitoring and personalized strategies remain crucial for optimizing outcomes in such intricate cases.

Coronary Artery Bypass Surgery: Evidence-Based Practice.

Coronary artery bypass graft (CABG) surgery remains a pivotal cornerstone, offering established symptomatic alleviation and prognostic advantages for patients grappling with complex multivessel and left main coronary artery diseases. Despite the lucid guidance laid out by contemporary guidelines regarding the choice between CABG and percutaneous coronary intervention (PCI), a notable hesitation persists among certain patients, characterized by psychological reservations, knowledge gaps, or individual beliefs that sway their inclination toward surgical intervention. This comprehensive review critically synthesizes the prevailing guidelines, modern practices, and outcomes pertaining to CABG surgery, delving into an array of techniques and advancements poised to enhance both short-term and enduring surgical outcomes. The exploration encompasses advances in on-pump and off-pump procedures, conduit selection strategies encompassing the bilateral utilization of internal mammary artery and radial artery conduits, meticulous graft evaluation methodologies, and the panorama of minimally invasive approaches, including those assisted by robotic technology. Furthermore, the review navigates the terrain of hybrid coronary revascularization, shedding light on the pivotal roles of shared decision-making and the heart team in shaping treatment pathways. As a comprehensive compendium, this review not only navigates the intricate landscape of CABG surgery but also aligns it with contemporary practices, envisioning its trajectory within the evolving currents of healthcare dynamics.

HBeAg testing is better than quantitative HBsAg assay as an alternative to HBV DNA assay among HBV-infected pregnant women.

INTRODUCTION: Using tenofovir disoproxil fumarate (TDF) is recommended in the 3rd trimester for pregnant women with HBV DNA ≥ 200,000 IU/mL to prevent mother-to-child transmission (MTCT) of hepatitis B virus (HBV). However, HBV DNA quantification is unavailable in many resource-limited areas worldwide, hence prophylaxis is often missed. The aim of this study was to determine whether HBeAg or qHBsAg is a better alternative to HBV DNA testing in HBV-infected pregnant women. METHODOLOGY: In this prospective cohort study, pregnant women with HBV infection were recruited in 3 hospitals from October 2019 to November 2020. Socio-demographic and clinical data were collected. Blood samples were taken for qHBsAg and HBV DNA testing. HBeAg results were collected from the medical records of the participants who visited a doctor during the study. RESULTS: 465 pregnant women met the study criteria. 41.9% were HBeAg positive, 33.3% had high qHBsAg levels (> 104 IU/mL), 38.3% had high HBV DNA levels (≥ 200,000 IU/mL). Pregnant women with high qHBsAg levels were 27 times more likely to have high HBV DNA levels (aOR = 27.0, 95% CI: 11.1-65.5, p < 0.001). Participants who were HBeAg positive were 57.5 times more likely to have high HBV DNA levels (aOR = 57.5, 95% CI: 23.0-140.0, p < 0.001). The sensitivity of qHBsAg and HBeAg was 80% and 94%, respectively; and specificity was 95% and 90%, respectively. CONCLUSIONS: HBeAg testing should be considered over qHBsAg assay as an alternative to HBV DNA assay because of its technical simplicity, lower cost, and fewer missed treatments.

Adoption of minimally invasive mitral valve surgery: single-centre implementation experience in Vietnam.

The adoption of minimally invasive mitral valve surgery (MIMVS) has become a prominent trend in mitral valve procedures. This article emphasizes that the success of the MIMVS program relies not only on effective teamwork but also on comprehensive hospital support and a clearly defined training strategy. Additionally, targeted marketing initiatives that highlight the value of the heart valve centre are crucial for sustaining the program's success and attracting a consistent patient flow. The implementation of these strategies requires diligent execution, consistent maintenance, and continuous improvement to ensure the triumph of the MIMVS program. This article aims to share our experience in implementing MIMVS at our centre, providing valuable insights for centres that have yet to adopt this approach or have low adoption rates. While acknowledging that sharing our centre's experience cannot guarantee success in all centres, customizing the implementation by selecting appropriate features and access points is vital. Each centre may encounter unique challenges, and tailoring the strategy to address specific needs will enhance the effectiveness of the MIMVS program.

A Systematic Review and Meta-Analysis on the Real-World Effectiveness of COVID-19 Vaccines against Infection, Symptomatic and Severe COVID-19 Disease Caused by the Omicron Variant (B.1.1.529).

Real-world data on the effectiveness of COVID-19 vaccines against the Omicron variant (B.1.1.529) is limited. This systematic review aimed to investigate the real-world effectiveness and durability of protection conferred by primary course and booster vaccines against confirmed Omicron infection, and severe outcomes. We systematically searched literature up to 1 August 2022. Meta-analysis was performed with the DerSimonian-Laird random-effects model to estimate the pooled vaccine effectiveness (VE). Overall, 28 studies were included representing 11 million individuals. The pooled VE against Omicron infection was 20.4% (95%CI: 12.1-28.7%) and 23.4% (95%CI: 13.5-33.3%) against symptomatic infection with variation based on vaccine type and age groups. VE sharply declined from 28.1% (95%CI: 19.1-37.1%) at three months to 3.9% (95%CI: -24.8-32.7%) at six months. Similar trends were observed for symptomatic Omicron infection. A booster dose restored protection against Omicron infection up to 51.1% (95%CI: 43.8-58.3%) and 57.3% (95%CI: 54.0-60.5%) against symptomatic infection within three months; however, this waned to 32.8% (95%CI: 16.8-48.7%) within six months. VE against severe Omicron infection following the primary course was 63.6% (95%CI: 57.5-69.7%) at three months, decreased to 49% (95%CI: 35.7-63.4%) within six months, and increased to 86% after the first or second booster dose.

Mechanism of Friedel-Crafts Acylation Using Metal Triflate in Deep Eutectic Solvents: An Experimental and Computational Study.

In this paper, we develop a method for Friedel-Crafts acylation using metal triflate in deep eutectic solvents. Various metal triflates were tested and provided good to excellent yields of corresponding ketone products. The density functional theory calculation revealed the metal effects on the formation of active intermediate acylium triflate as well as the acidic condition. The metal triflate in the deep eutectic solvent can be recovered and reused with a little loss in the catalytic activity.

Influence of Degree of Severe Plastic Deformation on Thermal Stability of an HfNbTiZr Multi-Principal Element Alloy Processed by High-Pressure Torsion.

Severe plastic deformation (SPD) is an effective route for the nanocrystallization of multi-principal element alloys (MPEAs). The stability of the refined microstructure is important, considering the high temperature applications of these materials. In the present study, the effect of SPD on the stability of a body-centered cubic (bcc) HfNbTiZr MPEA was investigated. SPD was performed using a high-pressure torsion (HPT) technique by varying the number of turns between ½ and 10. The evolution of phase composition and microstructure was studied near the disk centers and edges where the imposed strain values were the lowest and highest, respectively. Thus, the shear strain caused by HPT varies between 3 (½ turn, near the center) and 340 (10 turns, near the edge). It was found that during annealing up to 1000 K, the bcc HfNbTiZr alloy decomposed into two bcc phases with different lattice constants at 740 K. In addition, at high strains a hexagonal close packed (hcp) phase was formed above 890 K. An inhomogeneous elemental distribution was developed at temperatures higher than 890 K due to the phase decomposition. The scale of the chemical heterogeneities decreased from about 10 µm to 30 nm where the shear strain increased from 3 to 340, which is similar to the magnitude of grain refinement. Anneal-induced hardening was observed in the MPEA after HPT for both low and high strains at 740 K, i.e., the hardness of the HPT-processed samples increased due to heat treatment. At low strain, the hardness remained practically unchanged between 740 and 1000 K, while for the alloy receiving high strains there was a softening in this temperature range.