14 research outputs found
Formation of first star clusters under the supersonic gas flow -- I. Morphology of the massive metal-free gas cloud
We performed simulations of the first star formation with initial
supersonic gas flows relative to the dark matter at the cosmic recombination
era. Increasing the initial streaming velocities led to delayed halo formation
and increased halo mass, enhancing the mass of the gravitationally shrinking
gas cloud. For more massive gas clouds, the rate of temperature drop during
contraction, in other words, the structure asymmetry, becomes more significant.
When the maximum and minimum gas temperature ratios before and after
contraction exceed about ten, the asymmetric structure of the gas cloud
prevails, inducing fragmentation into multiple dense gas clouds. We continued
our simulations until years after the first dense core formation to
examine the final fate of the massive star-forming gas cloud. Among the
models studied, we find the simultaneous formation of up to four dense gas
clouds, with a total mass of about . While the gas mass in the
host halo increases with increasing the initial streaming velocity, the mass of
the dense cores does not change significantly. The star formation efficiency
decreases by more than one order of magnitude from to when the initial streaming velocity, normalised by the
root mean square value, increases from 0 to 3.Comment: 15 pages, 16 figures, 1 table, Accepted for publication in MNRA
Efficacy and safety of ultrasound-assisted wound debridement in the treatment of diabetic foot ulcers: a systematic review and meta-analysis of 11 randomized controlled trials
ObjectiveResearch data suggests that ultrasound-assisted wound debridement (UAWD) can effectively promote the healing of diabetic foot ulcers (DFU). However, existing research is not consistent with this viewpoint. Therefore, we conducted this study to investigate the effect of UAWD on the healing of diabetic foot ulcers.MethodsFrom the establishment of the database to January 2024, we searched 8 databases to study the effectiveness and safety of UAWD in the treatment of DFU. Two authors independently screened the qualifications of the articles, while two authors extracted relevant data. Statistical analysis was conducted using Review Manager 5.4 and STATA 18.0 software.ResultsA total of 11 randomized controlled studies were included, with 6 countries and 696 participants participating. Our findings showed that UAWD was associated with a significant benefit in healing rate (OR = 2.60, 95% CI: [1.67, 4.03], P < 0.0001, I2 = 25%), wound healing time (MD = -11.94, 95% CI: [-23.65, -0.23], P = 0.05, I2 = 99%), percentage reduction in wound size (MD = 14.2, 95% CI: [10.8, 17.6], P = 0.47, I2 = 32%), effectiveness of treatment (OR = 10.3, 95% CI: [4.68, 22.66], P < 0.00001, I2 = 0%). Moreover, UAWD did not cause any significant adverse reactions. However, there was no obvious difference in wound blood perfusion (MD = 0.25, 95% CI: [-0.01, 0.52], P = 0.06, I2 = 90%), transcutaneous oxygen partial pressure (MD = 14.34, 95% CI: [-10.03, 38.71], P = 0.25, I2 = 98%).ConclusionUAWD can significantly improve wound healing rate, shorten wound healing time, accelerate wound area reduction, and improve clinical treatment effectiveness without significant adverse reactions. Although there is no significant difference in transcutaneous oxygen pressure and wound blood flow perfusion between UAWD and SWC. So we look forward to more scientifically blinded, placebo-controlled, high-quality studies in the future, to enable researchers to obtain more complete and accurate analytical data, in order to improve the scientific and credibility of the evidence.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/, identifier CRD42024501198
Boosting Superior Lithium Storage Performance of AlloyâBased Anode Materials via Ultraconformal Sb CoatingâDerived Favorable SolidâElectrolyte Interphase
Alloy materials such as Si and Ge are attractive as highâcapacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during dischargeâcharge processes. Compared to the overâemphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solidâelectrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloyâbased anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li3Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiFâdominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sbâcoated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh gâ1 after 200 cycles at 500 mA gâ1, compared to only 72% and 170 mAh gâ1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve longâterm cycling stability for alloyâbased anode materials
Systemic immune inflammation index is associated with in-stent neoatherosclerosis and plaque vulnerability: An optical coherence tomography study
Background: In-stent neoatherosclerosis (ISNA) is identified as the primary cause of in-stent restenosis (ISR). The systemic immune inflammation index (SII), shows promise for predicting post-percutaneous coronary intervention (PCI) adverse cardiovascular events and is associated with coronary stenosis severity; however, its specific relationship with ISNA remains unclear. This study aimed to investigate the association between the SII and ISNA after drug-eluting stent (DES) implantation. Methods: This cross-sectional study included 195 participants with 195 ISR lesions who underwent optical coherence tomography (OCT)-guided PCI between August 2018 and October 2022. Participants were categorized based on the SII levels into Tertile 1 (SII 751.94, n = 65). Baseline Clinical, angiographic, and OCT characteristics were analyzed. The association of the SII with ISNA and thin-fibroatheroma (TCFA) was investigated using univariate and multivariate logistic regression analyses. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic accuracy of the SII in detecting ISNA and TCFA. Results: Patients in Tertile 3 had a significantly higher incidences of ISNA and TCFA than did those in Tertile 1. Logistic regression analysis revealed the SII is an independent indicator of ISNA and TCFA in ISR lesions (P = 0.045 and P = 0.002, respectively). The areas under the ROC curves for ISNA and TCFA were 0.611 and 0.671, respectively. Conclusion: The SII is associated with ISNA and TCFA and may serve as an independent indicator in patients with ISR
Formation of Multidomain Hydrogels via Thermally Induced Assembly of PISA-Generated Triblock Terpolymer Nanogels
Polymerization-induced
self-assembly (PISA) is a rapidly evolving
method for the efficient preparation of well-defined nano-objects.
PISA-generated nano-objects have been explored in this work for the
responsive formation of multidomain hydrogels by thermally induced
assembly of doubly thermoresponsive triblock terpolymer nanogels.
The nanogels consist of a thermoresponsive polyÂ(diethylene glycol
ethyl acrylate) (PDEGA) outer block with a lower thermal transition
temperature, a hydrophilic polyÂ(<i>N</i>,<i>N</i>-dimethylÂacrylamide) (PDMA) midblock, and a <i>N</i>,<i>N</i>â˛-methyleneÂbisÂ(acrylamide) (BIS)
cross-linked, thermoresponsive polyÂ(<i>N</i>-isopropylÂacrylamide)
(PNIPAM) core block with a higher thermal transition temperature.
The unique location of these two thermoresponsive blocks of differing
transition temperatures in the PDEGAâPDMAâPÂ(NIPAM-<i>co</i>-BIS) nanogels is rationally designed to facilitate room-temperature
gelation and is synthetically realized via judicious selection of
waterâethanol mixtures under dispersion polymerization conditions.
The nanogels were characterized by turbidimetry, dynamic light scattering
(DLS), and transmission electron microscopy (TEM). Gelation behavior
of the nanogels was investigated by the inverted vial method as well
as dynamic rheology sweeps. In comparison with PNIPAMâPDMAâPÂ(DEGA-<i>co</i>-BIS) nanogel and a triblock terpolymer of similar composition,
the PDEGAâPDMAâPÂ(NIPAM-<i>co</i>-BIS) nanogels
exhibit a good combination of gelation sensitivity and gel strength.
The gelation ability, sensitivity, and mechanical properties are affected
by the block ratios as well as the cross-linking density in the core
of the nanogels
Comparison of Neoatherosclerosis and Neovascularization of Restenosis after Drug-Eluting Stent Implantation: An Optical Coherence Tomography Study
Background: Neoatherosclerosis (NA) is associated with stent failure. However, systematic studies on the manifestations of NA and neovascularization (NV) at different stages after drug-eluting stent (DES) implantation are lacking. Moreover, the relationship between NA and NV in in-stent restenosis (ISR) has not been reported. This study aimed to characterize NA and NV in patients with ISR at different post-DES stages and compare the association between NA and NV in ISR lesions. Methods: A total of 227 patients with 227 lesions who underwent follow-up optical coherence tomography before percutaneous coronary intervention for DES ISR were enrolled and divided into early (E-ISR: 5 years) ISR groups. Furthermore, ISR lesions were divided into NV and non-NV groups according to the presence of NV. Results: The prevalence of NA and NV was 52.9% and 41.0%, respectively. The prevalence of lipidic NA (E-ISR, 32.7%; L-ISR, 50.0%; VL-ISR, 58.5%) and intimal NV (E-ISR, 14.5%; L-ISR, 30.8%; VL-ISR, 38.3%) increased with time after stenting. NA was higher in ISR patients with NV lesions than in those without (p < 0.001). Patients with both ISR and NV had a higher incidence of macrophage infiltration, thin-cap fibroatheroma, intimal rupture, and thrombosis (p < 0.01). Conclusions: Progression of lipidic NA was associated with L-ISR and VL-ISR but may not be related to calcified NA. NA was more common in ISR lesions with NV; its formation may substantially promote NA progression and plaque instability