Theoretical study of the structural and thermodynamic properties of U-He compounds under high pressure.

Uranium is considered as a very important nuclear energy material because of the huge amount of energy it releases. As the main product of the spontaneous decay of uranium, it is difficult for helium to react with uranium because of its chemical inertness. Therefore, bubbles will be formed inside uranium, which could greatly reduce the performance of uranium or cause safety problems. Additionally, nuclear materials are usually operated in an environment of high-temperature and high-pressure, so it is necessary to figure out the exact state of helium inside uranium under extreme conditions. Here, we explored the structural stability of the U-He system under high pressure and high temperature by using density functional theory calculations. Two metastable phases are found between 50 and 400 GPa: U4He with space group Fmmm and U6He with space group P1̄. Both are metallic and adopt layered structures. Electron localization function calculation combined with charge density difference analysis indicates that there are covalent bonds between U and U atoms in both Fmmm-U4He and P1̄-U6He. Regarding the elastic modulus of α-U, the addition of helium has certain influence on the mechanical properties of uranium. Besides, first-principles molecular dynamics simulations were carried out to study the dynamical behavior of Fmmm-U4He and P1̄-U6He at high-temperature. It was found that Fmmm-U4He and P1̄-U6He undergo one-dimensional superionic phase transitions at 150 GPa. Our study revealed the exotic structure of U-He compounds beyond the formation of bubbles under high-pressure and high-temperature, which might be relevant to the performance and safety issues of nuclear materials under extreme conditions.

Prognostic impact of serum chloride concentrations in acute heart failure patients: A systematic Rreview and meta-analysis.

OBJECTIVE: Acute heart failure (AHF) is a common disease in the emergency departments. Its occurrence is often accompanied by electrolyte disorders, but little attention is paid to chloride ion. Recent studies have shown that hypochloremia was associated with poor prognosis of AHF. Therefore, this meta-analysis aimed to assess the incidence of hypochloremia and the impact of the reduction of serum chloride on the prognosis of AHF patients. METHODS: We searched Cochrane Library, Web of science, PubMed, Embase databases and searched the relevant studies on chloride ion and AHF prognosis. The search time is from the establishment of the database to December 29, 2021. Two researchers screened the literature and extracted data independently. The quality of the included literature was evaluated using Newcastle-Ottawa Scale (NOS) scale. The effect amount is expressed as hazard ratio (HR) or relative risk (RR) and 95% confidence interval (CI). Review Manager 5.4.1 software for was used to perform the meta-analysis. RESULTS: Seven studies involving 6787 AHF patients were included in meta-analysis. Meta-analysis revealed that the incidence of hypochloremia in AHF patients at admission was 17% (95% CI: 0.11-0.22); One mmol /L decrease in serum chloride at admission was associated with 6% increased risk of all-cause death of AHF patients (HR = 1.06, 95% CI: 1.04-1.08, P < 0.00001); Compared with the non-hypochloremia group, the risk of all-cause death in the hypochloremia group increased by 1.71 times (RR = 1.71, 95% CI: 1.45-2.02, P < 0.00001), the risk of all-cause death in the progressive hypochloremia(development of hypochloremia after admission) group increased by 2.24 times (HR = 2.24, 95% CI: 1.72-2.92, P < 0.00001), and the risk of all-cause death in the persistent hypochloremia (hypochloremia both on admission and at discharge) group increased by 2.80 times (HR = 2.80, 95% CI: 2.10-3.72, P < 0.00001). CONCLUSION: The available evidence shows that the decrease of chloride ion at admission is associated with poor prognosis of AHF patients, and the prognosis of persistent hypochloremia is worse.Some outcome indicators(progressive hypochloremia, persistent hypochloremia, and composite of death + HF hospitalization)are as few as 2 studies in the literature, and the results should be interpreted carefully.

Intravenous diltiazem versus metoprolol for atrial fibrillation with rapid ventricular rate: A meta-analysis.

BACKGROUND: Intravenous diltiazem and metoprolol are both commonly used to treat atrial fibrillation (AF) with rapid ventricular rate (RVR) in the emergency department (ED), but the advantages and disadvantages of these drugs cannot be verified. This meta-analysis aimed to assess the efficacy and safety of intravenous diltiazem versus metoprolol for AF with RVR. METHOD: We systematically searched PubMed, Web of Science, Embase, Cochrane library, the China National Knowledge Infrastructure (CNKI), Wanfang, China Biology Medicine disc (CBM) and the WeiPu (VIP). Meta-analysis was performed using weighted mean difference (WMD), relative risk (RR) and 95% confidence interval (CI). Statistical analysis was performed using Review Manager 5.4.1. RESULTS: Seventeen studies involving 1214 patients in nine randomized controlled trials (RCTs) and eight cohort studies were included in meta-analysis, including 643 patients in the intravenous diltiazem group and 571 patients group in the intravenous metoprolol. The results of the meta-analysis showed that compared with intravenous metoprolol, intravenous diltiazem was found higher efficacy (RR =1.11; 95% CI = 1.06 to 1.16, p < 0.00001), shorter average onset time (RR = -1.13; 95% CI = -1.97 to -0.28, p = 0.009), lower ventricular rate (RR = -9.48; 95% CI = -12.13 to -6.82, p<0.00001), less impact on systolic blood pressure (WMD = 3.76; 95% CI: 0.20 to 7.33, P = 0.04), and no significant difference in adverse events (RR = 0.80, 95% CI = 0.55 to 1.14, P = 0.22) and diastolic blood pressure (WMD = -1.20; 95% CI: -3.43 to 1.04, P = 0.29) was found between intravenous diltiazem and metoprolol. CONCLUSION: Intravenous diltiazem has higher efficacy, shorter average onset time, lower ventricular rate, less impact on blood pressure, and with no increase in adverse events compared to intravenous metoprolol.

Modified Valsalva maneuver for treatment of supraventricular tachycardias: A Meta-analysis.

BACKGROUD: Valsalva maneuver (VM) is a simple and easy method for acute termination of supraventricular tachycardia (SVT), while a postural modification to the VM has been suggested to be superior to the standard VM (SVM). The objective of this meta-analysis is to explore the efficacy and safety of the modified VM (MVM) to terminate SVT compared with the SVM. METHODS: Extensive literature was conducted using the database such as PubMed, Embase, Web of Science, Cochrane library and included randomized controlled trials (RCTs) assessing the efficacy and safety of the MVM and SVM for SVT. Meta-analysis was performed using mean difference (MD), relative risk (RR) and 95% confidence interval (CI). Statistical analysis was performed using Review Manager 5.4.1 software. The quality of the published studies was evaluated using the Oxford quality scoring system (Jadad scale). RESULTS: Six RCTs involving 1208 patients were reviewed, including 603 patients in the MVM group and 605 patients in the SVM group. The results of the meta-analysis showed that MVM was found to significantly increase the success rate of the sinus rhythm after single VM (RR = 2.83; 95% CI = 2.19 to 3.66; P < 0.00001), sinus rhythm after multiple VM (RR = 3.83; 95% CI = 2.26 to 6.50; P < 0.00001), and single and multiple VM (RR = 2.85, 95% CI = 2.35 to 3.45; P < 0.00001). MVM also decreased the emergency anti-arrhythmic treatments (RR = 0.70; 95% CI = 0.62 to 0.79; P < 0.00001), and use of adenosine and verapamil (RR = 0.69; 95% CI = 0.61 to 0.78; P < 0.00001). There was no significant difference in adverse events (RR = 1.48; 95% CI = 0.91 to 2.42; P = 0.11) and time in emergency department (ED) (RR = 0.03; 95% CI = -0.17 to 0.23, P = 0.79) between MVM and SVM. CONCLUSION: Compared with MVM, the conversion rate of SVT to sinus rhythm was more effective than SVM. MVM also reduced the use of anti-arrhythmic measures and drugs, and had no increased time in ED and adverse events.

Shock-induced ejecta transport and breakup in reactive gas.

The transport process of micro-ejecta in reactive gases has recently attracted research attention and interest. Here, we investigate the interaction between shock-induced ejecta of Al and oxygen using a reactive molecular dynamics simulation. The results reveal that metal fragments ejected into reactive gases will quickly increase the temperature of the mixing zone, followed by the deceleration of spikes and a greater shock intensity in the compressed gases, compared with the ejection in inert gases. Moreover, we find that, in vacuum, only a small number of atoms fall out when spherical ejecta particles are finally formed. In the presence of inert gases, several small particles break away from the initial fragments during the transformation of the initially formed strip-shaped fragments into spherical particles, accompanying the detachment of a large number of atoms. When ejecta are transported in reactive gases, the chemical interactions cause more atoms to separate from particles, thus forming smaller fragments and more atomic particles. The research findings show that chemical reactions play an important role in ejecta transport and breakup, which should be considered in future ejecta-transport models for better predictions.

A transgenic plant cell-suspension system for expression of epitopes on chimeric Bamboo mosaic virus particles.

We describe a novel strategy to produce vaccine antigens using a plant cell-suspension culture system in lieu of the conventional bacterial or animal cell-culture systems. We generated transgenic cell-suspension cultures from Nicotiana benthamiana leaves carrying wild-type or chimeric Bamboo mosaic virus (BaMV) expression constructs encoding the viral protein 1 (VP1) epitope of foot-and-mouth disease virus (FMDV). Antigens accumulated to high levels in BdT38 and BdT19 transgenic cell lines co-expressing silencing suppressor protein P38 or P19. BaMV chimeric virus particles (CVPs) were subsequently purified from the respective cell lines (1.5 and 2.1 mg CVPs/20 g fresh weight of suspended biomass, respectively), and the resulting CVPs displayed VP1 epitope on the surfaces. Guinea pigs vaccinated with purified CVPs produced humoral antibodies. This study represents an important advance in the large-scale production of immunopeptide vaccines in a cost-effective manner using a plant cell-suspension culture system.

Intracardiac vs. transesophageal echocardiography for guiding transcatheter closure of interatrial communications: a systematic review and meta-analysis.

Background: Transcatheter closure of atrial septal defect (ASD) and patent foramen ovale (PFO) is an established practice, and it requires monitoring and guidance. Both transoesophageal echocardiography (TEE) and intracardiac echocardiography (ICE) can be used as guidance tools. However, the use of ICE and TEE in structural heart disease is controversial and the advantages and disadvantages of both for ASD and PFO closure need to be investigated. We did a systematic review and meta-analysis to compare the efficacy and safety of TEE and ICE for guiding transcatheter closure of ASD and PFO. Methods: A systematic search of Embase, PubMed, Cochrane library, Web of Science was conducted from inception to May 2022. The outcomes of this study included average time for both fluoroscopy and the procedure, complete closure, length of stay at hospital and adverse events. This study was performed using mean difference (MD), relative risk (RR) and 95% confidence interval (CI). Results: The meta-analysis was conducted with a total of 11 studies, involving 4,748 patients were included in meta-analysis, including 2,386 patients in the ICE group and 2,362 patients in the TEE group. The results of the meta-analysis showed that compared with TEE, ICE was shorter in time both fluoroscopy [MD: -3.72 (95%CI: -4.09 to -3.34) minutes, P < 0.00001] and the procedure [MD: -6.43 (95%CI: -7.65 to -5.21) minutes, P < 0.00001], shorter length of stay at hospital [MD = -0.95 (95% CI = -1.21 to -0.69) days, P < 0.00001], lower incidence of adverse events (RR = 0.72, 95%CI: 0.62 to 0.84, P < 0.0001), and the arrhythmia (RR = 0.50, 95% CI = 0.27 to 0.94, P = 0.03) and vascular complications (RR = 0.52, 95%CI = 0.29 to 0.92, P = 0.02) in ICE group were lower than those in TEE group. No significant difference in complete closure was found between ICE and TEE (RR = 1.00, 95% CI = 0.98 to 1.03, P = 0.74). Conclusion: Under the premise of ensuring successful rate of complete closure, ICE can shorten time between fluoroscopy and procedure and length of stay at hospital, and there was no increase in adverse events. However, more high-quality studies are needed to confirm the benefits of using ICE in ASD and PFO closure.