237 research outputs found
Tuning redox active polyoxometalates for efficient electronācoupled proton buffer mediated water splitting
We present strategies to tune the redox properties of polyoxometalate clusters to enhance the electronācoupled protonābufferāmediated water splitting process, in which the evolution of hydrogen and oxygen can occur in different forms and is separated in time and space. By substituting the heteroatom template in the Kegginātype polyoxometalate cluster, H6ZnW12O40, it is possible to double the number of electrons and protonation in the redox reactions (from two to four). This increase can be achieved with better matching of the energy levels as indicated by the redox potentials, compared to the ones of wellāstudied H3PW12O40 and H4SiW12O40. This means that H6ZnW12O40 can act as a highāperformance redox mediator in an electrolytic cell for the onādemand generation of hydrogen with a high decoupling efficiency of 95.5ā% and an electrochemical energy efficiency of 83.3ā%. Furthermore, the H6ZnW12O40 cluster also exhibits an excellent cycling behaviour and redox reversibility with almost 100ā% H2āmediated capacity retention during 200ā
cycles and a high coulombic efficiency >92ā% each cycle at 30ā
mAācmā2
Impact of stress hyperglycemia ratio on mortality in patients with cardiac arrest: insight from American MIMIC-IV database
BackgroundStress hyperglycemia ratio (SHR) has shown a predominant correlation with transient adverse events in critically ill patients. However, there remains a gap in comprehensive research regarding the association between SHR and mortality among patients experiencing cardiac arrest and admitted to the intensive care unit (ICU).MethodsA total of 535 patients with their initial ICU admission suffered cardiac arrest, according to the American Medical Information Mart for Intensive Care (MIMIC)-IV database. Patients were stratified into four categories based on quantiles of SHR. Multivariable Cox regression models were used to evaluate the association SHR and mortality. The association between SHR and mortality was assessed using multivariable Cox regression models. Subgroup analyses were conducted to determine whether SHR influenced ICU, 1-year, and long-term all-cause mortality in subgroups stratified according to diabetes status.ResultsPatients with higher SHR, when compared to the reference quartile 1 group, exhibited a greater risk of ICU mortality (adjusted hazard ratio [aHR] = 3.029; 95% CI: 1.802-5.090), 1-year mortality (aHR = 3.057; 95% CI: 1.885-4.958), and long-term mortality (aHR = 3.183; 95% CI: 2.020-5.015). This association was particularly noteworthy among patients without diabetes, as indicated by subgroup analysis.ConclusionElevated SHR was notably associated with heightened risks of ICU, 1-year, and long-term all-cause mortality among cardiac arrest patients. These findings underscore the importance of considering SHR as a potential prognostic factor in the critical care management of cardiac arrest patients, warranting further investigation and clinical attention
Razvoj kvantitativnog PCR testa temeljenog na SYBR Green I za identifikaciju cirkovirusa svinja 1, 2 i 3
Porcine Circovirus (PCV) includes Porcine Circovirus 1(PCV1), Porcine Circovirus 2 (PCV2) and Porcine Circovirus 3 (PCV3). In recent years, co-infection exists between PCV1, PCV2 and PCV3 serotypes. Therefore, it is particularly necessary to establish a fast, specific and sensitive SYBR Green I real-time quantitative PCR detection method for PCV1, PCV2 and PCV3. In this experiment, specific primers were selected and the reaction conditions were optimized. A real-time quantitative PCR identification method was established. The results showed the detection limits of this assay were 40.3 copies/Ī¼l for PCV1, 25.2 copies/Ī¼l for PCV2 and22.4 copies/ Ī¼l for PCV3. There was no cross-reactivity with swine fever virus (CSFV), porcine reproductive and respiratory syndrome virus (PRRSV), porcine pseudorabies virus (PRV) and porcine parvovirus (PPV). The intra-assay and inter-assay coefficients of variation were less than 1%. The test results of 100 PCV suspected positive samples revealed that the PCV1, PCV2 and PCV3 singular infection rate was 10% (10/100), 64% (64/100) and 52% (52/100), respectively. The PCV1 and PCV2 co-infection rate was 8% (8/100), the PCV1 and PCV3 co-infection rate was 7% (7/100), the PCV2 and PCV3 co-infection rate was 26% (26/100), and the PCV1, PCV2 and PCV3 co-infection rate was 7% (7/100). This method has good specificity, sensitivity and stability. It provides a promising tool for rapid differential detection of PCV1, PCV2 and PCV3.MeÄu cirkovirusima svinja razlikujemo cirkovirus svinja tipa 1 (PCV1), cirkovirus svinja tipa 2 (PCV2) i cirkovirus svinja tipa 3 (PCV3). Posljednjih se godina pojavljuje koinfekcija ovim trima serotipovima, stoga je potrebno uspostaviti brzu, specifiÄnu i osjetljivu metodu kako bi se kvantitativnim PCR testom temeljenom na SYBR Green I mogli identificirati PCV1, PCV2 i PCV3. U ovom su istraživanju upotrijebljene specifiÄne poÄetnice te su optimizirani uvjeti rekacije za uspostavljanje kvantitativnog PCR-a u stvarnom vremenu. Rezultati su pokazali da su granice detekcije ovog testa 40,3 kopije/Ī¼L za PCV1, 25,2 kopije/Ī¼L za PCV2 i 22,4 kopije/Ī¼L za PCV3. Nije bilo križne reaktivnosti s virusom svinjske kuge (CSFV), virusom reproduktivnog i respiratornog sindroma svinja (PRRSV), virusom pseudobjesnoÄe svinja (PRV) i parvovirusom svinja (PPV). Koeficijenti varijacije unutar testa i meÄu testovima bili su manji od 1 %. Rezultati analize 100 uzoraka sa sumnjom na PCV pokazali su da je stopa infekcije serotipom PCV1 bila 10% (10/100), PCV2 64% (64/100), a PCV3 52% (52/100). Stopa koinfekcije serotipovima PCV1 i PCV2 bila je 8% (8/100), PCV1 i PCV3 7% (7/100), a PCV2 i PCV3 26% (26/100). Koinfekcija svim trima serotipovima, PCV1, PCV2 i PCV3, bila je 7% (7/100). Metoda primjenjena u ovom istraživanju ima dobru specifiÄnost, osjetljivost i postojanost te je obeÄavajuÄi alat za brzo otkrivanje serotipova PCV1, PCV2 i PCV3
Dynamic diffusion tensor imaging reveals structural changes in the bilateral pyramidal tracts after brain stem hemorrhage in rats
Background and Purpose: Few studies have concentrated on pyramidal tract (PY) changes after brain stem hemorrhage (BSH). In this study, we used a diffusion tensor imaging (DTI) technique and histologic identification to investigate longitudinal PY changes on both the contralateral and ipsilateral sides after experimental BSH. Methods: BSH was induced in 61 Sprague-Dawley rats by infusing 30 Ī¼l of autogenous tail blood into each ratās right pons. DTI and motor function examinations were performed repeatedly on days 1, 3, 7, 14, and 28 after surgery. Fractional anisotropy, mean diffusivity, axial diffusivity, and radial diffusivity were measured in the bilateral PYs. The axon and myelin injury in the PY were evaluated by histologic study. Results: As compared with normal controls, the bilateral PYs in rats with induced BSH showed an early decrease and a late increase in fractional anisotropy and an early increase and a late decrease in mean diffusivity. A progressive decrease in axial diffusivity with dramatic axon loss from day 1 to day 28 after BSH was found bilaterally. The bilateral PYs showed an early increase and a late decrease in radial diffusivity. Early myelin injury and late repair were also detected pathologically in the bilateral PYs of rats with BSH. Thus, the early motor function deficits of rats with BSH began to improve on day 14 and had almost completely disappeared by day 28. Conclusions: DTI revealed dynamic changes in the bilateral PYs after BSH, which was confirmed by histologic findings and which correlated with motor function alteration. These findings support the idea that quantitative DTI can track structural changes in the bilateral PYs and that DTI may serve as a noninvasive tool to predict the prognoses of patients with BSH
Comparative and functional genomics reveals genetic diversity and determinants of host specificity among reference strains and a large collection of Chinese isolates of the phytopathogen Xanthomonas campestris pv. campestris
Construction of a microarray based on the genome of Xanthomonas campestris pv.campestris (Xcc), and its use to analyse 18 other virulent Xcc strains, revealed insights into the genetic diversity and determinants of host specificity of Xcc strains
Molecular detection of Bartonella species in wild small mammals in western Yunnan Province, China
BackgroundSmall mammals serve as the main reservoir for Bartonella and as a proxy indicator of the potential risk of Bartonella transmission from nature to humans. They offer a valuable early warning for human infection. Nevertheless, geographical variations in the impact of the host on the occurrence of Bartonella infection are underestimated. This study was designed to investigate the infection characteristics of Bartonella and explore its species diversity in wild small mammals in western Yunnan Province, China.MethodsWild small mammals were captured from Yulong, Jianchuan, and Lianghe counties in western Yunnan Province between 2015 and 2016. Real-time quantitative PCR (qPCR) was used to detect Bartonella infection, and the Bartonella species were identified by phylogenetic analysis. The factors associated with Bartonella infection in small mammals were analyzed by the Chi-square Test.ResultsThe prevalence of Bartonella in small mammals was 47.85% (768/1605). Lianghe County had the highest Bartonella infection rate, with 56.27% of the samples tested positive, followed by a rate of 50.91% was tested in Yulong County, and 39.97% in Jianchuan County (pā<ā0.001). Bartonella was detected positive in a total 25 small mammal species, with infection rates ranging from 2.17% to 100%. Niviventer fulvescens had the highest Bartonella infection rate. In comparison with the dominant small mammal species, Eothenomys mileyus had the lowest Bartonella infection rate than that in Apodemus chevrieri, Rattus tanezumi, and Apodemus draco (pā<ā0.001). Male small mammals had a higher infection rate than females (pā<ā0.05). The prevalence of Bartonella in small mammals during the summer season was higher compared to the other three seasons (pā<ā0.001). Woodland landscape had the highest Bartonella infection rate (pā<ā0.001). Bartonella rochalimae, B. japonica, B. tribocorum, B. washoensis, B. sylvatica, and B. rattimassiliensis were obtained from infected small mammals.ConclusionThis study showed a high prevalence of Bartonella was detected with various Bartonella species in small mammals in Yulong, Jianchuan, and Lianghe counties of western Yunnan Province. These findings hold significant scientific clues, providing valuable reference points for further research of Bartonella natural foci in Yunnan or other analogues environments
Chronic Unpredictable Mild Stress Promotes Atherosclerosis via HMGB1/TLR4-Mediated Downregulation of PPARĪ³/LXRĪ±/ABCA1 in ApoE-/- Mice
Background: Although our previous studies have confirmed that the activation of TLR4 is implicated in the development of atherosclerosis induced by chronic unpredicted mild stress (CUMS), the underling mechanism is largely unclear. Here, we hypothesized that CUMS accelerates atherosclerotic development through lowering PPARĪ³/LXRĪ±-ABCA1 expression via HMGB1/TLR4 signaling.Methods: In present study, CUMS atherosclerotic animal models were established with AopE-/- mice, and CUMS Raw 264.7 macrophage models were mimicked by high corticosterone treatment, These models were treated with Ethyl pyruvate (EP, an inhibitor of HMGB1), TLR4 inhibitor TAK-242, and PPARĪ³ agonist RSG (Rosiglitazone) to test our hypothesis, respectively.Results: Our results indicated that the protein levels of HMGB1, TLR4, and pro-inflammatory cytokines including IL-1Ī², TNF-Ī± were elevated with the development of atherosclerosis in CUMS mice, while the expressions of PPARĪ³, LXRĪ±, and ABCA1 declined. Notably, HMGB1 inhibition by EP reversed CUMS-induced atherosclerotic development, pro-inflammatory cytokines upregulation, and PPARĪ³/LXRĪ±-ABCA1 downregulation. The same trend was observed in the stressed mice treatment with TAK-242. Further experimental evidences indicated that EP, TAK-242, and RSG treatment notably corrected foam cell formation, HMGB1 release, and down-regulation of LXRĪ± and ABCA1 in CUMS Raw 264.7 macrophage model.Conclusion: These results indicate that CUMS exacerbates atherosclerosis is likely via HMGB1-mediated downregulation of PPARĪ³/LXRĪ±-ABCA1 through TLR4. These data reveal a novel mechanism by which CUMS aggravates atherosclerosis and may offer a potential therapeutic target for this disease
The Minimum Variation Timescales of X-ray bursts from SGR J1935+2154
The minimum variation timescale (MVT) of soft gamma-ray repeaters can be an
important probe to estimate the emission region in pulsar-like models, as well
as the Lorentz factor and radius of the possible relativistic jet in gamma-ray
burst (GRB)-like models, thus revealing their progenitors and physical
mechanisms. In this work, we systematically study the MVTs of hundreds of X-ray
bursts (XRBs) from SGR J1935+2154 observed by {\it Insight}-HXMT, GECAM and
Fermi/GBM from July 2014 to Jan 2022 through the Bayesian Block algorithm. We
find that the MVTs peak at 2 ms, corresponding to a light travel time
size of about 600 km, which supports the magnetospheric origin in pulsar-like
models. The shock radius and the Lorentz factor of the jet are also constrained
in GRB-like models. Interestingly, the MVT of the XRB associated with FRB
200428 is 70 ms, which is longer than that of most bursts and implies
its special radiation mechanism. Besides, the median of MVTs is 7 ms, shorter
than the median MVTs of 40 ms and 480 ms for short GRBs or long GRBs,
respectively. However, the MVT is independent of duration, similar to GRBs.
Finally, we investigate the energy dependence of MVT and suggest that there is
a marginal evidence for a power-law relationship like GRBs but the rate of
variation is at least about an order of magnitude smaller. These features may
provide an approach to identify bursts with a magnetar origin.Comment: accepted for publication in ApJ
Proton-Boron Fusion Yield Increased by Orders of Magnitude with Foam Targets
A novel intense beam-driven scheme for high yield of the tri-alpha reaction
11B(p,{\alpha})2{\alpha} was investigated. We used a foam target made of
cellulose triacetate (TAC, C_9H_{16}O_8) doped with boron. It was then heated
volumetrically by soft X-ray radiation from a laser heated hohlraum and turned
into a homogenous, and long living plasma. We employed a picosecond laser pulse
to generate a high-intensity energetic proton beam via the well-known Target
Normal Sheath Acceleration (TNSA) mechanism. We observed up to 10^{10}/sr
{\alpha} particles per laser shot. This constitutes presently the highest yield
value normalized to the laser energy on target. The measured fusion yield per
proton exceeds the classical expectation of beam-target reactions by up to four
orders of magnitude under high proton intensities. This enhancement is
attributed to the strong electric fields and nonequilibrium thermonuclear
fusion reactions as a result of the new method. Our approach shows
opportunities to pursue ignition of aneutronic fusion
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