76 research outputs found

    Stress-driven crystallization via shear-diffusion transformations in a metallic glass at very low temperatures

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    At elevated temperatures, glasses crystallize via thermally activated diffusion. However, metallic glasses can also undergo deformation-induced crystallization at very low temperatures. Here we demonstrate the crystallization of Al[subscript 50]Fe[subscript 50] metallic glasses under cyclic deformation at 50 K using molecular dynamics simulations and reveal the underlying atomic-scale processes. We demonstrate that stress-driven nonaffine atomic rearrangements, or shear diffusion transformation (SDT) events, lead to successive metabasin-to-metabasin transitions and long-range ordering. We also illustrate that the nucleation and growth of the crystal proceed via collective attachment of ordered clusters, advancing the amorphous/crystal interface in an intermittent manner. The cooperative nature of the steplike crystallization is attributed to the large activation volume of Eshelby transformations which generate as a by-product nonaffine diffusive atomic displacements that accumulate over loading cycles. The dual nature of shear (affine) and diffusion (nonaffine) in low-temperature stress-driven SDT events thus unifies inelasticity with crystallization.National Basic Research Program of China (973 Program) (Grant 2012CB619402)National Basic Research Program of China (111 Program) (Grant B06025)National Science Foundation (U.S.) (Grant DMR-1120901)National Science Foundation (U.S.) (Grant DMR-1410636

    The Effects of Aspirin With Combined Compound Danshen Dropping Pills on Hemorheology and Blood Lipids in Middle-Aged and Elderly Patients With CHD: A Systematic Review and Meta-Analysis

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    Background: Coronary heart disease (CHD) is one of the most common diseases in clinical cardiovascular practice, mainly afflicting the middle-aged and elderly. It will greatly affect elderly quality of life, and even affect their psychological and physical health. At present, CHD is treated with western drugs alone, but this can produce drug dependency. In recent years, Traditional Chinese Medicine (TCM) combine western drugs has been used as a complementary and alternative therapy, and its effectiveness and safety have been proven, attracting the attention of numerous researchers.Objective: Our study aimed to compare the efficacy of Aspirin with Combined Compound Danshen Dropping Pills had a superior effect on the treatment of Hemorheology and Blood Lipids in Middle-aged and Elderly Patients with CHD. Determine the effectiveness and safety of Aspirin with Combined Compound Danshen Dropping Pills in the treatment of CHD, and obtain high quality clinical evidence.Methods: Based on the PRISMA Statement, inclusion and exclusion criteria were formulated. Randomized controlled trials (RCTs) on the Effects of Aspirin with Combined Compound Danshen Dropping Pills on Hemorheology and Blood Lipids in Middle-aged and Elderly Patients with CHD were found following a search of 4 mainstream medical databases. RCTs found to meet the study's requirement were included; data information was then extracted, and the quality assessed using the Cochrane bias risk assessment tool. Through RevMan software, Meta analysis was carried out for overall TC, TG, HDL-C, LDL-C hematocrit, high shear viscosity, low shear viscosity, plasma viscosity, PAGM, and TXB2 effective rate. The relative risk (RR) and 95% confidence interval (95% CI) were calculated; heterogeneity was tested and its source found; publication bias was assessed through the Egger and Begg tests, and by means of funnel plots.Result: 22 RCTs were found, involving 1,987 cases. The results of the Meta analysis showed that, compared to drug therapy alone, Aspirin with Combined Compound Danshen Dropping Pills had a superior effect on the treatment of Hemorheology and Blood Lipids in Middle-aged and Elderly Patients with CHD. The meta analysis results show the effects on TC [MD = −0.91, 95% CI (−1.09, −0.73)], on TG [MD = −0.94, 95% CI (−1.22, −0.66)], on HDL-C [MD = 0.40, 95% CI (0.27, 0.53)], on LDL-C [MD = −0.99, 95% CI (−1.24, −0.74)], on hematocrit [MD = −2.69, 95% CI (−3.73, −1.65)], on high shear blood viscosity [MD = −1.11, 95% CI (−2.18, −0.05)], on low shear viscosity [MD = −0.79, 95% CI (−0.89, −0.68)], on plasma viscosity [MD = −0.26, 95% CI (−0.52, 0.01)], on PAMG [MD = −10.75, 95% CI (−16.84, −4.67)], and on TXB2 [MD = −11.84, 95% CI (−14.75, −8.92)]. The source of heterogeneity might be related to the state of patient, efficacy of drugs in the control group and difference in judgment criteria for efficacy. The Egger test and Begg test showed that publication bias did not occur in our study.Conclusions: The combination of compound dropping pill DSP with aspirin has some therapeutic effect on blood lipids and hemorheology in patients with CHD, ince some of the RCTs featured a very small sample size, the reliability and validity of our study's conclusion may have been affected as well; therefore, the explanation should be treated with some caution. In the future, a large number of higher-quality RCTs are still needed to confirm the results of our study

    Clinical Efficacy of Infantile Massage in the Treatment of Infant Functional Constipation: A Meta-Analysis

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    Background: Functional constipation in children is a common disease that causes a psychological burden on infants and young children across the world. It will greatly affect infant quality of life in early childhood and even affect their psychological and physical health. At present, infant functional constipation is treated with western drugs alone, but this can produce drug dependency. In recent years, Traditional Chinese Medicine (TCM) infant massage has been used as a complementary and alternative therapy, and its effectiveness and safety have been proven, attracting the attention of numerous researchers.Objective: Our study aimed to compare the influence of infant massage intervention on defecation frequency and consistency, determine the effectiveness, and safety of infant massage in the treatment of infant functional constipation, and obtain high-quality clinical evidence.Methods: Based on the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement, inclusion, and exclusion criteria were formulated. Randomized controlled trials (RCTs) on TCM infant massage for the treatment of infant functional constipation were found following a search of four mainstream medical databases. RCTs found to meet the study's requirement were included; data information was then extracted, and the quality was assessed using the Cochrane bias risk assessment tool. Through RevMan software, a meta-analysis was carried out for overall effective rate, stool form, defecation frequency, defecation difficulty, and constipation symptom scoring index. The relative risk (RR) and 95% confidence interval (95% CI) were calculated, heterogeneity was tested and its source was found, and publication bias was assessed through the Egger's and Begg's tests and by means of funnel plots.Results: A total of 23 RCTs and 2,005 patients were included. The results of the meta-analysis showed that compared to drug therapy alone, TCM infant massage had a superior effect on the treatment of infant functional constipation. This difference was statistically significant (p < 0.05) and evaluated according to the overall effective rate (RR = 1.25; 95% CI = 1.17, 1.33), defecation frequency [mean difference (MD) = −0.72; 95% CI = −0.80, −0.65], and constipation symptom score (MD = −0.81; 95% CI = −1.20, −0.43), showing that TCM infant massage is indeed superior to drug therapy alone in the treatment of infant functional constipation. TCM infant massage was found to be equivalent to drug therapy alone in terms of the stool form score [−0.30 (−0.38, −0.22)] and the defecation difficulty score [−0.73 (−0.81, −0.65)], since the difference was not statistically significant (p > 0.05). The source of heterogeneity might be related to the state of patient, manipulation of the massages, efficacy of drugs in the control group, and difference in judgment criteria for efficacy. The Egger's test and Begg's test showed that publication bias did not occur in our study.Conclusion: TCM infant massage can increase defecation frequency and reduce the symptoms of constipation in children suffering from functional constipation; in addition, the clinical trial showed beneficial effects. Since some of the RCTs featured a very small sample size, the reliability and validity of our study's conclusion may have been affected as well; therefore, the explanation should be treated with some caution. In the future, a large number of higher-quality RCTs are still needed to confirm the results of our study

    Pressure-stabilized divalent ozonide CaO3 and its impact on Earth's oxygen cycles.

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    High pressure can drastically alter chemical bonding and produce exotic compounds that defy conventional wisdom. Especially significant are compounds pertaining to oxygen cycles inside Earth, which hold key to understanding major geological events that impact the environment essential to life on Earth. Here we report the discovery of pressure-stabilized divalent ozonide CaO3 crystal that exhibits intriguing bonding and oxidation states with profound geological implications. Our computational study identifies a crystalline phase of CaO3 by reaction of CaO and O2 at high pressure and high temperature conditions; ensuing experiments synthesize this rare compound under compression in a diamond anvil cell with laser heating. High-pressure x-ray diffraction data show that CaO3 crystal forms at 35 GPa and persists down to 20 GPa on decompression. Analysis of charge states reveals a formal oxidation state of -2 for ozone anions in CaO3. These findings unravel the ozonide chemistry at high pressure and offer insights for elucidating prominent seismic anomalies and oxygen cycles in Earth's interior. We further predict multiple reactions producing CaO3 by geologically abundant mineral precursors at various depths in Earth's mantle

    Ferromagnetic quasi-atomic electrons in two-dimensional electride.

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    An electride, a generalized form of cavity-trapped interstitial anionic electrons (IAEs) in a positively charged lattice framework, shows exotic properties according to the size and geometry of the cavities. Here, we report that the IAEs in layer structured [Gd2C]2+·2e- electride behave as ferromagnetic elements in two-dimensional interlayer space and possess their own magnetic moments of ~0.52 μB per quasi-atomic IAE, which facilitate the exchange interactions between interlayer gadolinium atoms across IAEs, inducing the ferromagnetism in [Gd2C]2+·2e- electride. The substitution of paramagnetic chlorine atoms for IAEs proves the magnetic nature of quasi-atomic IAEs through a transition from ferromagnetic [Gd2C]2+·2e- to antiferromagnetic Gd2CCl caused by attenuating interatomic exchange interactions, consistent with theoretical calculations. These results confirm that quasi-atomic IAEs act as ferromagnetic elements and trigger ferromagnetic spin alignments within the antiferromagnetic [Gd2C]2+ lattice framework. These results present a broad opportunity to tailor intriguing ferromagnetism originating from quasi-atomic interstitial electrons in low-dimensional materials

    Diagnostic performance and clinical impact of blood metagenomic next-generation sequencing in ICU patients suspected monomicrobial and polymicrobial bloodstream infections

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    IntroductionEarly and effective application of antimicrobial medication has been evidenced to improve outcomes of patients with bloodstream infection (BSI). However, conventional microbiological tests (CMTs) have a number of limitations that hamper a rapid diagnosis.MethodsWe retrospectively collected 162 cases suspected BSI from intensive care unit with blood metagenomics next-generation sequencing (mNGS) results, to comparatively evaluate the diagnostic performance and the clinical impact on antibiotics usage of mNGS.Results and discussionResults showed that compared with blood culture, mNGS detected a greater number of pathogens, especially for Aspergillus spp, and yielded a significantly higher positive rate. With the final clinical diagnosis as the standard, the sensitivity of mNGS (excluding viruses) was 58.06%, significantly higher than that of blood culture (34.68%, P<0.001). Combing blood mNGS and culture results, the sensitivity improved to 72.58%. Forty-six patients had infected by mixed pathogens, among which Klebsiella pneumoniae and Acinetobacter baumannii contributed most. Compared to monomicrobial, cases with polymicrobial BSI exhibited dramatically higher level of SOFA, AST, hospitalized mortality and 90-day mortality (P<0.05). A total of 101 patients underwent antibiotics adjustment, among which 85 were adjusted according to microbiological results, including 45 cases based on the mNGS results (40 cases escalation and 5 cases de-escalation) and 32 cases on blood culture. Collectively, for patients suspected BSI in critical condition, mNGS results can provide valuable diagnostic information and contribute to the optimizing of antibiotic treatment. Combining conventional tests with mNGS may significantly improve the detection rate for pathogens and optimize antibiotic treatment in critically ill patients with BSI

    Dissociation products and structures of solid H2 S at strong compression

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    Hydrogen sulfides have recently received a great deal of interest due to the record high superconducting temperatures of up to 203 K observed on strong compression of dihydrogen sulfide (H2S). A joint theoretical and experimental study is presented in which decomposition products and structures of compressed H2S are characterized, and their superconducting properties are calculated. In addition to the experimentally known H2S and H3S phases, our first-principles structure searches have identified several energetically competitive stoichiometries that have not been reported previously; H2S3, H3S2, and H4S3. In particular, H4S3 is predicted to be thermodynamically stable within a large pressure range of 25-113 GPa. High-pressure room-temperature X-ray diffraction measurements confirm the presence of H3S and H4S3 through decomposition of H2S that emerge at 27 GPa and coexist with residual H2S, at least up to the highest pressure studied in our experiments of 140 GPa. Electron-phonon coupling calculations show that H4S3 has a small Tc of below 2 K, and that H2S is mainly responsible for the observed superconductivity of samples prepared at low temperature (<100K).Y. L. and J. H. acknowledge funding from the National Natural Science Foundation of China under Grant No. 11204111 and No. 11404148, the Natural Science Foundation of Jiangsu province under Grant No. BK20130223, and the PAPD of Jiangsu Higher Education Institutions. Y. Z. and Y. M. acknowledge funding from the National Natural Science Foundation of China under Grant Nos. 11274136 and 11534003, the 2012 Changjiang Scholars Program of China. R. J. N. acknowledges financial support from the Engineering and Physical Sciences Research Council (EPSRC) of the U.K. [EP/J017639/1]. Calculations were performed on the Cambridge High Performance Computing Service facility and the HECToR and Archer facilities of the U.K.’s national highperformance computing service (for which access was obtained via the UKCP consortium [EP/K013564/1]). J. R. N. acknowledges financial support from the Cambridge Commonwealth Trust. I. E. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (FIS2013-48286-C2-2-P). M. C. acknowledges support from the Graphene Flagship and Agence nationale de la recherche (ANR), Grant No. ANR-13-IS10- 0003-01. Work at Carnegie was partially supported by EFree, an Energy Frontier Research Center funded by the DOE, Office of Science, Basic Energy Sciences under Award No. DE-SC-0001057 (salary support for H. L.). The infrastructure and facilities used at Carnegie were supported by NNSA Grant No. DE-NA-0002006, CDAC.This is the author accepted manuscript. The final version is available from the American Physical Society via http://dx.doi.org/10.1103/PhysRevB.93.02010
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