110 research outputs found

    Interferences effects in polarized nonlinear Breit-Wheeler process

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    The creation of polarized electron-positron pairs by the nonlinear Breit-Wheeler process in short laser pulses is investigated using the Baier-Katkov semiclassical method beyond local-constant-field approximation (LCFA), which allows for identifying the interferences effects in the positron polarization. When the laser intensity is in the intermediate %multiphoton regime, the interferences of pair production in different formation lengths induce an enhancement of pair production probability for spin-down positrons, which significantly affects the polarization of created positrons. The polarization features are distinct from that obtained with LCFA, revealing the invalidity of LCFA in this regime. Meanwhile, the angular distribution for different spin states varies, resulting in an angular-dependent polarization of positrons. The average polarization of positrons at beam center is highly sensitive to the laser's carrier-envelope phase (CEP), which provides a potential alternative way of determining the CEP of strong lasers. The verification of the observed interference phenomenon is possible for the upcoming experiments

    Comparison of efficacy of conbercept, aflibercept, and ranibizumab ophthalmic injection in the treatment of macular edema caused by retinal vein occlusion: a Meta-analysis

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    AIM: To evaluate and compare the anatomical and functional outcomes and negative effects of the three anti-vascular endothelial growth factor (VEGF) drugs in the treatment of macular edema (ME) due to retinal vein occlusion (RVO) based on the evidence pooled from current clinical trials and observational studies. METHODS: A systematic literature search was conducted on nine online databases from inception until April 30, 2022. The main endpoints were best corrected visual acuity (BCVA), central macular thickness (CMT), and adverse events (AEs). Cumulative Meta-analysis was conducted to synthesize the outcomes of the drugs. The retrieved data were analyzed using Stata software (version 12.0). RESULTS: A total of 20 studies comprising 1674 eyes met the inclusion criteria to the Meta-analysis. It was observed that conbercept and aflibercept had better visual acuity effects compared with ranibizumab at 1mo [weight mean difference (WMD)=-0.03, P=0.001; WMD=-0.05, P=0.019], but the effects were not different from that of ranibizumab at 6mo. Moreover, there was not statistically significant difference in the proportion of patients gaining ≥15 letters at 12-24mo between aflibercept and ranibizumab [odds ratio (OR)=1.16, P=0.427]. Conbercept had higher mean CMT change effects at 1mo (WMD= -14.43, P=0.014) and 6mo (WMD=-35.63, P≤0.001) compared with ranibizumab. Meanwhile, the mean CMT change effects at 1mo (WMD=-10.14, P=0.170), 6mo (WMD=-26.98, P=0.140) and 12-24mo (WMD=-12.34, P=0.071) were comparable among the groups. Similarly, AEs were not significantly different among the treatments (OR=0.75, P=0.305; OR=1.04, P=0.89). The stability of effect size of mean BCVA and CMT improved with the increase in sample size. Aflibercept and conbercept required fewer injections compared with ranibizumab. CONCLUSION: This is the first study to evaluate the efficacy and AEs of intravitreal administration of conbercept, ranibizumab, and aflibercept in the treatment of RVO-ME. Intravitreal aflibercept or conbercept results in better mean change in vision and CMT reduction compared with ranibizumab. Conbercept can be considered to be a promising and innovative drug with good anti-VEGF effects

    The impact of gum-chewing on postoperative ileus following gynecological cancer surgery: A systematic review and meta-analysis of randomized controlled trials

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    ObjectiveTo assess the effect and safety of gum-chewing on the prevention of postoperative ileus after gynecological cancer surgery.MethodsWe conducted a systematic review of randomized controlled trials (RCTs) published between 2000 and 2022 in English and Chinese, using the EBSCO, Web of Science, Scopus, Cochrane Central Register of Controlled Trials (Cochrane database), PubMed, Medline (via Ovid), Chinese National Knowledge Infrastructure (CNKI), China Science and Technology Journal Database, and Wan Fang databases. A total of 837 studies were screened using Endnote software, and those that met the inclusion criteria were selected for analysis. The main outcome of interest was the incidence of postoperative ileus, and secondary outcomes included time to first flatus, time to first bowel movement, and length of hospital stay.ResultsTwo authors extracted data and performed quality assessment independently. The review included six RCTs with a total of 669 patients. Compared with routine care, gum-chewing could significantly reduce the incidence of postoperative ileus (RR 0.46, 95% CI: 0.30, 0.72, P=0.0006), shorten the time to first flatus (WMD -9.58, 95% CI: -15.04, -4.12, P=0.0006), first bowel movement (WMD -11.31, 95% CI: -21.05, -1.56, P=0.02), and the length of hospital stay (WMD -1.53, 95% CI: -2.08, -0.98, P<0.00001).ConclusionsGum-chewing is associated with early recovery of gastrointestinal function after gynecological cancer surgery and may be an effective and harmless intervention to prevent postoperative ileus.Systemaic review registrationhttps://www.crd.york.ac.uk/prospero/#searchadvanced, identifier CRD42022384346

    SARS-CoV-2 infection severity is linked to superior humoral immunity against the spike

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently causing a global pandemic. The antigen specificity of the antibody response mounted against this novel virus is not understood in detail. Here, we report that subjects with a more severe SARS-CoV-2 infection exhibit a larger antibody response against the spike and nucleocapsid protein and epitope spreading to subdominant viral antigens, such as open reading frame 8 and nonstructural proteins. Subjects with a greater antibody response mounted a larger memory B cell response against the spike, but not the nucleocapsid protein. Additionally, we revealed that antibodies against the spike are still capable of binding the D614G spike mutant and cross-react with the SARS-CoV-1 receptor binding domain. Together, this study reveals that subjects with a more severe SARS-CoV-2 infection exhibit a greater overall antibody response to the spike and nucleocapsid protein and a larger memory B cell response against the spike

    Polyclonal epitope mapping reveals temporal dynamics and diversity of human antibody responses to H5N1 vaccination

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    Novel influenza A virus (IAV) strains elicit recall immune responses to conserved epitopes, making them favorable antigenic choices for universal influenza virus vaccines. Evaluating these immunogens requires a thorough understanding of the antigenic sites targeted by the polyclonal antibody (pAb) response, which single-particle electron microscopy (EM) can sensitively detect. In this study, we employ EM polyclonal epitope mapping (EMPEM) to extensively characterize the pAb response to hemagglutinin (HA) after H5N1 immunization in humans. Cross-reactive pAbs originating from memory B cells immediately bound the stem of HA and persisted for more than a year after vaccination. In contrast, de novo pAb responses to multiple sites on the head of HA, targeting previously determined key neutralizing sites on H5 HA, expanded after the second immunization and waned quickly. Thus, EMPEM provides a robust tool for comprehensively tracking the specificity and durability of immune responses elicited by novel universal influenza vaccine candidates

    Progression of SARS-CoV-2 seroprevalence in St. Louis, Missouri, through January 2021

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    Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seropositivity was assessed for 3,066 individuals visiting hospitals in St. Louis, Missouri, during July 2020, November 2020, or January 2021. Seropositivity in children increased from 5.22% in July to 21.16% in January. In the same time frame, seropositivity among adults increased from 4.52% to 19.03%, prior to initiation of mass vaccination

    A herpesvirus encoded Qa-1 mimic inhibits natural killer cell cytotoxicity through CD94/NKG2A receptor engagement

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    A recurrent theme in viral immune evasion is the sabotage of MHC-I antigen presentation, which brings virus the concomitant issue of \u27missing-self\u27 recognition by NK cells that use inhibitory receptors to detect surface MHC-I proteins. Here, we report that rodent herpesvirus Peru (RHVP) encodes a Qa-1 like protein (pQa-1) via RNA splicing to counteract NK activation. While pQa-1 surface expression is stabilized by the same canonical peptides presented by murine Qa-1, pQa-1 is GPI-anchored and resistant to the activity of RHVP pK3, a ubiquitin ligase that targets MHC-I for degradation. pQa-1 tetramer staining indicates that it recognizes CD94/NKG2A receptors. Consistently, pQa-1 selectively inhibits NKG2

    Genome-wide exploration of genetic interactions for bladder cancer risk

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    Although GWASs have been conducted to investigate genetic variation of bladder tumorigenesis, little is known about genetic interactions that may influence bladder cancer (BC) risk. By leveraging large-scale participants from UK Biobank, we established a discovery database with 4000 Caucasian participants (2000 cases vs 2000 non-cases), a database with 1648 Caucasian participants (824 cases vs 824 non-cases) and 856 non-Caucasian participants (428 cases vs 428 non-cases) as validation. We then performed a genome-wide SNP-SNP interaction investigation related to BC risk based a machine learning approach (ie, GenEpi). Moreover, we used the selected interactions to build a BC screening model with an integrated interaction-empowered polygenic risk score (iPRS) based on Cox proportional hazard model. With Bonferroni correction, we identified 10 statistically significant pairs of SNPs, which located in 17 chromosomes. Of these, four SNP-SNP interactions were found to be positively associated with BC risk among Caucasian participants (ORs 1.57-2.03), while six SNP-SNP interactions showed negatively associated with BC risk (ORs 0.54-0.65). Only four of the SNP-SNP interactions were consistently identified in non-Caucasian participants located in ST7L-ADSS2, FHIT-CHDH, LARP4B-LHPP and RBFOX3-MPRIP. In addition, the iPRS showed a HR of 1.81 (95% CI: 1.46-2.09) compared the highest tertile to the lowest tertile, with an enhanced AUC (0.91; 95% CI:0.85-0.97) than PRS (AUC: 0.86; 95% CI:0.76-0.95; P-DeLong test = 2.2 × 10−4). In summary, this study identified several important SNP-SNP interactions for BC risk, and developed an iPRS model for BC screening, which may help to identify the people at high-risk state of BC before early manifestation

    A single intranasal or intramuscular immunization with chimpanzee adenovirus-vectored SARS-CoV-2 vaccine protects against pneumonia in hamsters

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    The development of an effective vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the etiologic agent of coronavirus disease 2019 (COVID-19), is a global priority. Here, we compare the protective capacity of intranasal and intramuscular delivery of a chimpanzee adenovirus-vectored vaccine encoding a prefusion stabilized spike protein (chimpanzee adenovirus [ChAd]-SARS-CoV-2-S) in Golden Syrian hamsters. Although immunization with ChAd-SARS-CoV-2-S induces robust spike-protein-specific antibodies capable of neutralizing the virus, antibody levels in serum are higher in hamsters vaccinated by an intranasal compared to intramuscular route. Accordingly, against challenge with SARS-CoV-2, ChAd-SARS-CoV-2-S-immunized hamsters are protected against less weight loss and have reduced viral infection in nasal swabs and lungs, and reduced pathology and inflammatory gene expression in the lungs, compared to ChAd-control immunized hamsters. Intranasal immunization with ChAd-SARS-CoV-2-S provides superior protection against SARS-CoV-2 infection and inflammation in the upper respiratory tract. These findings support intranasal administration of the ChAd-SARS-CoV-2-S candidate vaccine to prevent SARS-CoV-2 infection, disease, and possibly transmission
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