1,671 research outputs found

    Exact results of one-dimensional repulsive Hubbard model

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    We present analytical results of fundamental properties of one-dimensional (1D) Hubbard model with a repulsive interaction, ranging from fractional excitations to universal thermodynamics, interaction-driven criticality, correlation functions, Contact susceptibilities and quantum cooling. Using the exact solutions of the Bethe Ansatz equations of the Hubbard model, we first rigorously calculate the gapless spin and charge excitations, exhibiting exotic features of fractionalized spinons and holons. Based on the analysis on the fractional charge and spin excitations, the spin-incoherent Luttinger liquid with only the charge propagation mode is elucidated by the asymptotic of the two-point correlation functions with the help of the conformal field theory. Near quadruple critical point, we then further analytically obtain the thermodynamical properties, dimensionless ratios and scaling functions near quantum phase transitions in terms of chemical potential, magnetic field and interaction. In particular, we determine additivity rules of spin and charge susceptibilities, and derive explicit forms of thermodynamics of spin-incoherent Luttinger liquid. Finally, in order to capture deeper insight into the Mott insulator and interaction driven criticality, we further study the double occupancy and its associated Contact and Contact susceptibilities through which an adiabatic cooling scheme upon the quantum criticality is introduced.Comment: slight changes, 50 pages +18 figures, new analytical result

    Spin incoherent liquid and interaction-driven criticality in 1D Hubbard model

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    A rigorous understanding of the spin incoherent Tomonaga-Luttinger liquid (TLL), which displays solely a propagating charge mode but not a spin mode, and the interaction-driven quantum phase transitions in one-dimensional (1D) systems still remain elusive. In this Letter, we report the universal properties of spin incoherent TLL and interaction-driven criticality of the 1D repulsive Hubbard model by means of fractional charge and spin excitations, asymptotic of correlation functions as well as the lattice Contact. We build up an essential connection of Contact susceptibilities to the variations of density, magnetization and entropy with respect to the interaction strength, providing a rigorous understanding of interaction-driven phase transitions, Mott insulator and quantum cooling in the model. These relations hold true for higher dimensional systems.Comment: 4 figures 6 page

    Cryptotanshinone ameliorates hemorrhagic shock-induced liver injury via activating the Nrf2 signaling pathway

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    Introduction. Hemorrhagic shock (HS) is an important cause of high mortality in traumatized patients. Cryptotanshinone(CTS) is a bioactive compound extracted from Salvia miltiorrhiza Bunge (Danshen). The current study aimed to explore the effect and underlying mechanism of CTS on the liver injury induced by HS.Material and methods. Male Sprague-Dawley rats were used to establish the HS model by hemorrhaging and monitoring mean arterial pressure (MAP). CTS was intravenously administered at concentration of 3.5 mg/kg, 7 mg/kg, or 14 mg/kg 30 minutes before resuscitation. Twenty-four hours after resuscitation, the liver tissue and serum samples were collected for the following examinations. Hematoxylin and eosin (H&E) staining was used to evaluate hepatic morphology changes. The myeloperoxidase (MPO) activity in liver tissue and the serum activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were examined to reveal the extent of liver injury. The protein expression of Bax and Bcl-2 in liver tissue was detected by western blot. The TUNEL assay determined the apoptosis of hepatocytes. Oxidative stress of liver tissue was assessed by the examination of reactive oxygen species (ROS) generation. The content of malondialdehyde (MDA), glutathione (GSH), and adenosine triphosphate (ATP), the activity of superoxide dismutase (SOD) and oxidative chain complexes (complex I, II, III, IV), as well as cytochrome c expression in cytoplasm and mitochondria, were also used to determine the extent of oxidative injury in the liver. Immunofluorescence (IF) was employed to estimate nuclear factor E2-related factor 2 (Nrf2) expression. The mRNA and protein levels of heme oxygenase 1 (HO-1), NAD(P)H: quinone oxidoreductases 1 (NQO1), cyclooxygenase-2 (COX-2), and nitric oxide synthase (iNOS) were assessed by real-time qPCR, western blot to investigate the mechanism of CTS regulating HS-induced liver injury.Results. H&E staining and a histological score of rat liver suggested that HS induced liver injury. The activity of ALT, AST, and MPO was significantly increased by HS treatment. After CTS administration the ALT, AST, and MPO activities were suppressed, which indicates the liver injury was alleviated by CTS. The HS-induced upregulation of the TUNEL-positive cell rate was suppressed by various doses of CTS. HS-induced ROS production was decreased and the protein expression of Bax and Bcl-2 in the HS-induced rat liver was reversed by CTS administration. In the liver of HS-induced rats, the upregulation of MDA content and the downregulation of GSH content and SOD activity were suppressed by CTS. Additionally, CTS increases ATP content and mitochondrial oxidative complexes activities and suppressed the release of cytochrome c from mitochondria to the cytoplasm. Moreover, IF and western blot demonstrated that the activation of Nrf2 blocked by HS was recovered by different doses of CTS in liver tissue. The expression of downstream enzymes of the Nrf2 pathway, including HO-1, NQO1, COX-2, and iNOS, was reversed by CTS in the HS rat model.Conclusions. The current study for the first time revealed the protective effect of CTS in HS-induced liver injury. CTSeffectively recovered hepatocyte apoptosis, oxidative stress, and mitochondria damage induced by HS in the rat liverpartly via regulating the Nrf2 signaling pathway

    A Unified Framework for Modality-Agnostic Deepfakes Detection

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    As AI-generated content (AIGC) thrives, deepfakes have expanded from single-modality falsification to cross-modal fake content creation, where either audio or visual components can be manipulated. While using two unimodal detectors can detect audio-visual deepfakes, cross-modal forgery clues could be overlooked. Existing multimodal deepfake detection methods typically establish correspondence between the audio and visual modalities for binary real/fake classification, and require the co-occurrence of both modalities. However, in real-world multi-modal applications, missing modality scenarios may occur where either modality is unavailable. In such cases, audio-visual detection methods are less practical than two independent unimodal methods. Consequently, the detector can not always obtain the number or type of manipulated modalities beforehand, necessitating a fake-modality-agnostic audio-visual detector. In this work, we introduce a comprehensive framework that is agnostic to fake modalities, which facilitates the identification of multimodal deepfakes and handles situations with missing modalities, regardless of the manipulations embedded in audio, video, or even cross-modal forms. To enhance the modeling of cross-modal forgery clues, we employ audio-visual speech recognition (AVSR) as a preliminary task. This efficiently extracts speech correlations across modalities, a feature challenging for deepfakes to replicate. Additionally, we propose a dual-label detection approach that follows the structure of AVSR to support the independent detection of each modality. Extensive experiments on three audio-visual datasets show that our scheme outperforms state-of-the-art detection methods with promising performance on modality-agnostic audio/video deepfakes.Comment: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessibl

    Implementation interventions to promote the uptake of evidence-based practices in stroke rehabilitation (Review)

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    Background Rehabilitation based upon research evidence gives stroke survivors the best chance of recovery. There is substantial research to guide practice in stroke rehabilitation, yet uptake of evidence by healthcare professionals is typically slow and patients often do not receive evidence‐based care. Implementation interventions are an important means to translate knowledge from research to practice and thus optimise the care and outcomes for stroke survivors. A synthesis of research evidence is required to guide the selection and use of implementation interventions in stroke rehabilitation. Objectives To assess the effects of implementation interventions to promote the uptake of evidence‐based practices (including clinical assessments and treatments recommended in evidence‐based guidelines) in stroke rehabilitation and to assess the effects of implementation interventions tailored to address identified barriers to change compared to non‐tailored interventions in stroke rehabilitation. Search methods We searched CENTRAL, MEDLINE, Embase, and eight other databases to 17 October 2019. We searched OpenGrey, performed citation tracking and reference checking for included studies and contacted authors of included studies to obtain further information and identify potentially relevant studies. Selection criteria We included individual and cluster randomised trials, non‐randomised trials, interrupted time series studies and controlled before‐after studies comparing an implementation intervention to no intervention or to another implementation approach in stroke rehabilitation. Participants were qualified healthcare professionals working in stroke rehabilitation and the patients they cared for. Studies were considered for inclusion regardless of date, language or publication status. Main outcomes were healthcare professional adherence to recommended treatment, patient adherence to recommended treatment, patient health status and well‐being, healthcare professional intention and satisfaction, resource use outcomes and adverse effects. Data collection and analysis Two review authors independently selected studies for inclusion, extracted data, and assessed risk of bias and certainty of evidence using GRADE. The primary comparison was any implementation intervention compared to no intervention. Main results Nine cluster randomised trials (12,428 patient participants) and three ongoing trials met our selection criteria. Five trials (8865 participants) compared an implementation intervention to no intervention, three trials (3150 participants) compared one implementation intervention to another implementation intervention, and one three‐arm trial (413 participants) compared two different implementation interventions to no intervention. Eight trials investigated multifaceted interventions; educational meetings and educational materials were the most common components. Six trials described tailoring the intervention content to identified barriers to change. Two trials focused on evidence‐based stroke rehabilitation in the acute setting, four focused on the subacute inpatient setting and three trials focused on stroke rehabilitation in the community setting. We are uncertain if implementation interventions improve healthcare professional adherence to evidence‐based practice in stroke rehabilitation compared with no intervention as the certainty of the evidence was very low (risk ratio (RR) 1.19, 95% confidence interval (CI) 0.53 to 2.64; 2 trials, 39 clusters, 1455 patient participants; I2 = 0%). Low‐certainty evidence indicates implementation interventions in stroke rehabilitation may lead to little or no difference in patient adherence to recommended treatment (number of recommended performed outdoor journeys adjusted mean difference (MD) 0.5, 95% CI –1.8 to 2.8; 1 trial, 21 clusters, 100 participants) and patient psychological well‐being (standardised mean difference (SMD) –0.02, 95% CI –0.54 to 0.50; 2 trials, 65 clusters, 1273 participants; I2 = 0%) compared with no intervention. Moderate‐certainty evidence indicates implementation interventions in stroke rehabilitation probably lead to little or no difference in patient health‐related quality of life (MD 0.01, 95% CI –0.02 to 0.05; 2 trials, 65 clusters, 1242 participants; I2 = 0%) and activities of daily living (MD 0.29, 95% CI –0.16 to 0.73; 2 trials, 65 clusters, 1272 participants; I2 = 0%) compared with no intervention. No studies reported the effects of implementation interventions in stroke rehabilitation on healthcare professional intention to change behaviour or satisfaction. Five studies reported economic outcomes, with one study reporting cost‐effectiveness of the implementation intervention. However, this was assessed at high risk of bias. The other four studies did not demonstrate the cost‐effectiveness of interventions. Tailoring interventions to identified barriers did not alter results. We are uncertain of the effect of one implementation intervention versus another given the limited very low‐certainty evidence. Authors' conclusions We are uncertain if implementation interventions improve healthcare professional adherence to evidence‐based practice in stroke rehabilitation compared with no intervention as the certainty of the evidence is very low

    Generation of cold polyatomic molecular ions by ion-atom collisions

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    A goal of studies on ultracold chemical reactions is the formation of ultracold molecules containing three or more atoms. Although the first ultracold polyatomic molecules were formed recently; knowledge of the kinetics of polyatomic molecular ions as reaction products remains limited. Thus, we studied ion-atom reaction collisions in a continuous-wave (CW) laser photoionization of cold atoms in an Rb-Rb+^+ hybrid trap. A series of polyatomic molecular ions was produced, with precise changes in the atomic number of one rubidium atom. Using resonant-excitation mass spectrometry, we directly observed Rb3+_3^+ and Rb4+_4^+ molecular ions in time-of-flight mass spectrum for the first time. The information of the quantum state of these polyatomic molecular ions and the influence factors was obtained by measuring their lifetimes. The approach is simple, robust, and suitable for all types of laser-coolable elements. Our work paves the way for ultracold ion-atom chemical reactions, introduces the concept of polyatomic molecular ion platforms, and deepens the understanding of ion-atom reaction collisions. It has important implications for astronomical sciences, ultracold neutral plasma, cluster physics, and other disciplines.Comment: 6 figures and 1 supplemental figure

    Hypoxia inducible factor-1α suppresses Peroxiredoxin 3 expression to promote proliferation of CCRCC cells

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    AbstractPeroxiredoxin 3 (Prx3) is a mitochondrial member of the antioxidant family of thioredoxin peroxidases that uses mitochondrial thioredoxin 2 as a source of reducing equivalents to scavenge hydrogen peroxide (H2O2). Here, we report that the protein levels of Prx3 are significantly reduced in VHL-deficient clear cell renal cell carcinoma (CCRCC). Furthermore, stabilization of HIF-1α protein, caused either by VHL deficiency under normoxia, or by hypoxia, significantly reduced Prx3 expression. Luciferase-reporter and chromatin-immunoprecipitation assays indicated that HIF-1α binds to the hypoxia-responsive elements of PRDX3 promoter and represses its transcription. Finally, shRNA-based assays suggested that Prx3 downregulation is required for the HIF-1α-dependent proliferation of CCRCC cells. Taken together, our results shed new light onto the mechanism of HIF-1α-dependent proliferation in CCRCC cells
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