36 research outputs found
Radiative decay branching ratio of the Hoyle state
The triple-alpha process is a vital reaction in nuclear astrophysics,
characterized by two consecutive reactions
() that drive
carbon formation. The second reaction occurs through the Hoyle state, a 7.65
MeV excited state in with .The rate of the
process depends on the radiative width, which can be determined by measuring
the branching ratio for electromagnetic decay. Recent measurements by Kib\'edi,
\textit{et al.} conflicted with the adopted value and resulted in a significant
increase of nearly 50\% in this branching ratio, directly affecting the
triple-alpha reaction. This work aims to utilize charged-particle spectroscopy
with magnetic selection as a means to accurately measure the total radiative
branching ratio () of the Hoyle state in . The Hoyle state in was populated via inelastic scattering. The scattered -particles
were detected using a E-E telescope, while the recoiled
ions were identified in a magnetic spectrometer. A radiative branching ratio
value of was obtained. The radiative branching ratio for
the Hoyle state obtained in this work is in agreement with the original adopted
value. Our result suggests that the proton-- spectroscopy
result reported by Kib\'edi \textit{et al.} may be excluded
Development and validation of a patient-specific model to predict postoperative SIRS in older patients: A two-center study
IntroductionPostoperative systemic inflammatory response syndrome (SIRS) is common in surgical patients especially in older patients, and the geriatric population with SIRS is more susceptible to sepsis, MODS, and even death. We aimed to develop and validate a model for predicting postoperative SIRS in older patients.MethodsPatients aged â„65âyears who underwent general anesthesia in two centers of Third Affiliated Hospital of Sun Yat-sen University from January 2015 to September 2020 were included. The cohort was divided into training and validation cohorts. A simple nomogram was developed to predict the postoperative SIRS in the training cohort using two logistic regression models and the brute force algorithm. The discriminative performance of this model was determined by area under the receiver operating characteristics curve (AUC). The external validity of the nomogram was assessed in the validation cohort.ResultsA total of 5,904 patients spanning from January 2015 to December 2019 were enrolled in the training cohort and 1,105 patients from January 2020 to September 2020 comprised the temporal validation cohort, in which incidence rates of postoperative SIRS were 24.6 and 20.2%, respectively. Six feature variables were identified as valuable predictors to construct the nomogram, with high AUCs (0.800 [0.787, 0.813] and 0.822 [0.790, 0.854]) and relatively balanced sensitivity (0.718 and 0.739) as well as specificity (0.718 and 0.729) in both training and validation cohorts. An online risk calculator was established for clinical application.ConclusionWe developed a patient-specific model that may assist in predicting postoperative SIRS among the aged patients
Stress triggering effect on the 2022 Honghe MS5.0 earthquake with historical strong earthquakes
The 2022 Honghe MS5.0 seismic event is intriguing due to its occurrence in the south of the Red River Fault, an area historically lacking seismic activities greater than MS5.0. To elucidate the seismogenic mechanism and scrutinize stress-triggered interactions, we calculated co-seismic and post-seismic Coulomb stress alterations induced by nine historical seismic events (MÂ â„Â 6.0). The analysis reveals that these substantial seismic events provoked co-seismic stress augmentations of 1.409Â bar and post-seismic stress increments of 0.159Â bar. Noteworthy seismic events, such as the 1833 Songming, 1877 Shiping, 1913 Eshan, and 1970 Tonghai earthquakes, catalyzed the occurrence of the Honghe earthquake. Areas of heightened future seismic risk include the southern region of the Red River Fault and the eastern segments of the Shiping-Jianshui and Qujiang faults. Additionally, we assessed the correlation between the spatial distribution of aftershocks and the Coulomb stress shift triggered by the mainshock, taking into account the influence of calculation parameter settings
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Electrolytes in Organic Batteries
Organic batteries using redox-active polymers and small organic compounds have become promising candidates for next-generation energy storage devices due to the abundance, environmental benignity, and diverse nature of organic resources. To date, tremendous research efforts have been devoted to developing advanced organic electrode materials and understanding the material structure-performance correlation in organic batteries. In contrast, less attention was paid to the correlation between electrolyte structure and battery performance, despite the critical roles of electrolytes for the dissolution of organic electrode materials, the formation of the electrode-electrolyte interphase, and the solvation/desolvation of charge carriers. In this review, we discuss the prospects and challenges of organic batteries with an emphasis on electrolytes. The differences between organic and inorganic batteries in terms of electrolyte property requirements and charge storage mechanisms are elucidated. To provide a comprehensive and thorough overview of the electrolyte development in organic batteries, the electrolytes are divided into four categories including organic liquid electrolytes, aqueous electrolytes, inorganic solid electrolytes, and polymer-based electrolytes, to introduce different components, concentrations, additives, and applications in various organic batteries with different charge carriers, interphases, and separators. The perspectives and outlook for the future development of advanced electrolytes are also discussed to provide a guidance for the electrolyte design and optimization in organic batteries. We believe that this review will stimulate an in-depth study of electrolytes and accelerate the commercialization of organic batteries
Impact of Oral Health Behaviors on Dental Caries in Children with Intellectual Disabilities in Guangzhou, China
Dental care is consistently reported as one of the primary medical needs of children with disabilities (IDC). The aim of the present study was to explore the influence of oral health behaviors on the caries experience in children with intellectual disabilities in Guangzhou, China. A cross-sectional study was carried out in 477 intellectually disabled children, 12 to 17 years old, who were randomly selected from special educational schools in Guangzhou. A self-administered parental questionnaire was used to collect data on socio-demographic characteristics and oral health behavior variables, and 450 valid questionnaires were returned. Multiple regression analysis was used to examine the factors associated with dental caries. The average age of those in the sample was 14.6 years (SD = 1.3), 68.4% of whom were male, and the caries prevalence rate was 53.5% (DMFT = 1.5 ± 2.0). The factors significantly affecting the development of dental caries in IDC included gender, the presence or absence of cerebral palsy, and the frequency of dental visits and toothbrushing. In conclusion, the presence of cerebral palsy contributed to an increase risk of caries experience in intellectually disabled children, while toothbrushing more than twice a day and routine dental visits were caries-protective factors. Oral health promotion action may lead to a reduction in dental caries levels in IDC
Boosting the performance of hybrid supercapacitors through redox electrolyte-mediated capacity balancing
Hybrid supercapacitors (HSCs) are promising new energy storage devices offering both high power density and good energy density. However, because of the energy storage mechanism difference in two electrodes, the capacity imbalance issue is challenging which often results in limited specific capability in the HSCs. The conventional approach by balancing the mass of electrode materials could extend the operating voltage window but sacrificing the specific capacity. To fundamentally address this problem, here we propose a new concept of asymmetric electrolyte design in the HSCs where NiCo layered double hydroxide (LDH) battery-type electrode operates in the KOH electrolyte while electrolyte-soluble redox couples are deliberately introduced to the carbon capacitive electrode. The redox couples contribute extra faradic capacity to the capacitive carbon electrode, resolving the capacity imbalance problem in the two electrodes with equal mass loading. The optimized HSC delivers extraordinary high specific energy of 79.6 Wh/kg, which is about 4 times the value in the pristine unbalanced device (20.3 Wh/kg). This new conceptual design could be extended to other energy storage systems to further improve performance
Methylene-Bridged Tridentate Salicylaldiminato Binuclear Titanium Complexes as Copolymerization Catalysts for the Preparation of LLDPE through [Fe]/[Ti] Tandem Catalysis
Synthesis of MAX Phase Nanofibers and Nanoflakes and the Resulting MXenes
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Acylamido-based anion-functionalized ionic liquids for efficient synthesis of poly(isosorbide carbonate)
Using biomass and renewable feedstocks to prepare high value-added products instead of conventional petrochemicals has received extensive attention recently. In this work, a facile and phosgene-free approach for synthesizing bio-based polycarbonate is developed via melt polycondensation of isosorbide (ISB) and dimethyl carbonate (DMC), which are both derived from renewable biomass resources and CO2. Several kinds of acylamido-based anion-functionalized ionic liquids (ILs) are prepared and used as catalysts to promote the reaction of ISB and DMC. Their catalytic performances in the transesterification stage and the polycondensation stage are evaluated. Results show that acylamido-based ILs with a low anion-cation interaction energy and a high natural population analysis atomic charges of the nitrogen atom exhibited good catalytic performance. Furthermore, by using tetrabutylphosphonium phthalimide as the catalyst, the selectivity of carboxymethylation of DMC and conversion of ISB significantly increased to 99.6% and 99.0%, respectively. Quantum chemical calculations reveal that the dramatic enhancement of endo-OH reactivity originated from the interactions between the acylamido and -OH groups. Based on the NMR data and DFT calculations, a plausible synergistic catalytic mechanism involving cation-anion is proposed. This work not only provides guidance for the design and synthesis of efficient IL catalysts, but also is applicable to exploring the industrial possibilities of developing value-added bioproducts from renewable feedstocks