89 research outputs found

    Life Prediction of Gas Turbine Materials

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    Early Non-Response as a Predictor of Later Non-Response to Antipsychotics in Schizophrenia: A Randomized Trial

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    BACKGROUND: It remains a challenge to predict the long-term response to antipsychotics in patients with schizophrenia who do not respond at an early stage. This study aimed to investigate the optimal predictive cut-off value for early non-response that would better predict later non-response to antipsychotics in patients with schizophrenia. METHODS: This multicenter, 8-week, open-label, randomized trial was conducted at 19 psychiatric centers throughout China. All enrolled participants were assigned to olanzapine, risperidone, amisulpride, or aripiprazole monotherapy for 8 weeks. The positive and negative syndrome scale (PANSS) was evaluated at baseline, week 2, week 4, and week 8. The main outcome was the prediction of nonresponse. Nonresponse is defined as a \u3c 20% reduction in the total scores of PANSS from baseline to endpoint. Severity ratings of mild, moderate, and severe illness corresponded to baseline PANSS total scores of 58, 75, and 95, respectively. RESULTS: At week 2, a reduction of \u3c 5% in the PANSS total score showed the highest total accuracy in the severe and mild schizophrenia patients (total accuracy, 75.0% and 80.8%, respectively), and patients who were treated with the risperidone and amisulpride groups (total accuracy, 82.4%, and 78.2%, respectively). A 10% decrease exhibited the best overall accuracy in the moderate schizophrenia patients (total accuracy, 84.0%), olanzapine (total accuracy, 79.2%), and aripiprazole group (total accuracy, 77.4%). At week 4, the best predictive cut-off value was \u3c 20%, regardless of the antipsychotic or severity of illness (total accuracy ranging from 89.8 to 92.1%). CONCLUSIONS: Symptom reduction at week 2 has acceptable discrimination in predicting later non-response to antipsychotics in schizophrenia, and a more accurate predictive cut-off value should be determined according to the medication regimen and baseline illness severity. The response to treatment during the next 2 weeks after week 2 could be further assessed to determine whether there is a need to change antipsychotic medication during the first four weeks. TRIAL REGISTRATION: This study was registered on Clinicaltrials.gov (NCT03451734)

    Monitoring the Process and Characterizing Symptoms of Suckling Mouse Inoculation Promote Isolating Viruses from Ticks

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    Suckling mouse inoculation is an important method that has been used for years to isolate viruses from ticks; however, this method has usually been briefly described in the literature on a case-by-case basis upon successful isolation rather than providing extensive details. This study describes the procedure from preparation of tick homogenates to identification of virus isolation using the suckling mouse inoculation method. The transient and persistent features were characterized and the incidence of manifestations that developed in the suckling mice, especially in mice from which viruses were isolated, is reported. We identified 22 symptoms that developed in mice, including 13 transient symptoms that recovered by the end of the observation period and 7 persistent symptoms that the mice suffered from throughout the observation period. Persistent symptoms (lateral positioning and dead) and transient symptoms (malaise, emaciation, and difficulty turning over) were the main symptoms based on the high overall incidence. Moreover, we showed that mice from which viruses were isolated had a concentrated period and advanced days of disease onset. This study provides detailed information necessary for better use of suckling mouse inoculation to isolate viruses from ticks, which may benefit optimization of this method to identify, discover, and acquire tick-borne viruses

    An integrated creep-fatigue theory for material damage modeling

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    This paper presents an integrated creep-fatigue (ICF) theory to describe the non-linear creep-fatigue interaction during thermo-mechanical loading. The ICF theory recognizes the damage evolution as a holistic process consisting of nucleation and propagation of surface or subsurface cracks in coalescence with internally distributed damage, leading to final fracture. In a polycrystalline material under combined cyclic and dwell loading, crack nucleation and propagation occurs by fatigue or oxidation mechanisms, whereas internally distributed damage often occurs in the form of grain boundary cavities or microcracks due to creep or dwell effects, particularly at high temperatures. Based on the above mechanism, a damage evolution equation is mathematically derived, and the generality of the above physical mechanisms warrants the applicability of the ICF theory over a wide range of stresses and temperatures. This paper uses Mar-M 509, a cobalt base superalloy, as an example to illustrate how the ICF theory describes creep and low cycle fatigue (LCF).Peer reviewed: YesNRC publication: Ye

    A model of non-linear fatigue-creep (dwell) interactions

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    NRC publication: Ye

    A Higher-Order Theory for Fiber-Metal Laminates

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    Peer reviewed: YesNRC publication: Ye

    A Higher-order Theory for Fiber-Metal Laminates (Abstract)

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    Peer reviewed: YesNRC publication: Ye

    Client Following Former Audit Partners and Audit Quality: Evidence from Unforced Audit Firm Changes in China

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    In China's audit market, audit clients occasionally follow an audit partner who moves to another audit firm in an unforced setting (i.e., not due to the predecessor audit firm suffering regulatory sanctions). By examining a sample of Chinese listed companies during 2001–2013, we find that turnover audit partners are significantly less likely to issue a modified audit report to their unforced follower clients, as compared either with all other audits in the same successor audit firm in the same year, or with post-follow audits of forced follower clients (where the predecessor audit firm suffers regulatory sanctions). We also document evidence of turnover partners treating unforced follower clients favorably prior to the partner turnover event. Our evidence suggests that a close audit partner–client bonding impairs audit quality when lacking regulatory and public attention, and has implications for regulators, investors, and audit firms' quality control in emerging markets where clients are usually closely tied to audit partners rather than to the audit firm, and where a non-compete agreement between an audit partner and the audit firm is unavailable or weakly enforced

    A mechanism-based approach from low cycle fatigue to thermomechanical fatigue life prediction

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    Deformation and damage accumulation occur by fundamental dislocation and diffusion mechanisms. An integrated creep\u2013fatigue theory (ICFT) has been developed, based on the physical strain decomposition rule that recognizes the role of each deformation mechanism, and thus relate damage accumulation to its underlying physical mechanism(s). The ICFT formulates the overall damage accumulation as a holistic damage process consisting of nucleation and propagation of surface/subsurface cracks in coalescence with internally distributed damage/discontinuities. These guiding principles run through both isothermal low cycle fatigue (LCF) and thermomechanical fatigue (TMF) under general conditions. This paper presents a methodology using mechanism-based constitutive equations to describe the cyclic stress\u2013strain curve and the nonlinear damage accumulation equation incorporating (i) rate-independent plasticity-induced fatigue, (ii) intergranular embrittlement (IE), (iii) creep, and (iv) oxidation to predict LCF and TMF lives of ductile cast iron (DCI). The complication of the mechanisms and their interactions in this material provide a good demonstration case for the model, which is in good agreement with the experimental observations.Peer reviewed: YesNRC publication: Ye
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