51 research outputs found

    No Go Theorem for Kinematic Self-Similarity with A Polytropic Equation of State

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    We have investigated spherically symmetric spacetimes which contain a perfect fluid obeying the polytropic equation of state and admit a kinematic self-similar vector of the second kind which is neither parallel nor orthogonal to the fluid flow. We have assumed two kinds of polytropic equations of state and shown in general relativity that such spacetimes must be vacuum.Comment: 5 pages, no figures. Revtex. One word added to the title. Final version to appear in Physical Review D as a Brief Repor

    Time definition of reintubation most relevant to patient outcomes in critically ill patients: a multicenter cohort study

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    Background: Reintubation is a common complication in critically ill patients requiring mechanical ventilation. Although reintubation has been demonstrated to be associated with patient outcomes, its time definition varies widely among guidelines and in the literature. This study aimed to determine the association between reintubation and patient outcomes as well as the consequences of the time elapsed between extubation and reintubation on patient outcomes. Methods: This was a multicenter retrospective cohort study of critically ill patients conducted between April 2015 and March 2021. Adult patients who underwent mechanical ventilation and extubation in intensive care units (ICUs) were investigated utilizing the Japanese Intensive Care PAtient Database. The primary and secondary outcomes were in-hospital and ICU mortality. The association between reintubation and clinical outcomes was studied using Cox proportional hazards analysis. Among the patients who underwent reintubation, a Cox proportional hazard analysis was conducted to evaluate patient outcomes according to the number of days from extubation to reintubation. Results: Overall, 184,705 patients in 75 ICUs were screened, and 1849 patients underwent reintubation among 48,082 extubated patients. After adjustment for potential confounders, multivariable analysis revealed a significant association between reintubation and increased in-hospital and ICU mortality (adjusted hazard ratio [HR] 1.520, 95% confidence interval [CI] 1.359–1.700, and adjusted HR 1.325, 95% CI 1.076–1.633, respectively). Among the reintubated patients, 1037 (56.1%) were reintubated within 24 h after extubation, 418 (22.6%) at 24–48 h, 198 (10.7%) at 48–72 h, 111 (6.0%) at 72–96 h, and 85 (4.6%) at 96–120 h. Multivariable Cox proportional hazard analysis showed that in-hospital and ICU mortality was highest in patients reintubated at 72–96 h (adjusted HR 1.528, 95% CI 1.062–2.197, and adjusted HR 1.334, 95% CI 0.756–2.352, respectively; referenced to reintubation within 24 h). Conclusions: Reintubation was associated with a significant increase in in-hospital and ICU mortality. The highest mortality rates were observed in patients who were reintubated between 72 and 96 h after extubation. Further studies are warranted for the optimal observation of extubated patients in clinical practice and to strengthen the evidence for mechanical ventilation.Tanaka A., Shimomura Y., Uchiyama A., et al. Time definition of reintubation most relevant to patient outcomes in critically ill patients: a multicenter cohort study. Critical Care 27, 378 (2023); https://doi.org/10.1186/s13054-023-04668-3

    Prescription trend and lactic acidosis in patients prescribed metformin before and after the revision of package insert for allowing metformin administration to patients with moderately decreased kidney function based on real-world data from MID-NET® in Japan

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    IntroductionThis study was conducted to understand the impact of package insert (PI) revision in Japan on 18 June 2019 to allow metformin use for patients with moderately decreased kidney function (30 ≤ estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m2).MethodsA new user cohort design was employed to examine the prescription trend and the occurrence of lactic acidosis in patients prescribed metformin before and after PI revision using the Medical Information Database Network (MID-NET®).ResultsFrom 12 May 2016 to 31 March 2020, 5,874 patients (before, n = 4,702; after, n = 1,172) were identified as new metformin users, including 1,145 patients (before, n = 914; after, n = 231) with moderately decreased kidney function. Although no marked changes in metformin prescription were observed before and after PI revision, the daily metformin dose at the first prescription decreased after PI revision. For both before and after PI revision, less than 10 cases of lactic acidosis occurred in all patients prescribed metformin, and no lactic acidosis was observed in patients with moderately decreased kidney function.ConclusionThe results of this study are useful for understanding the safety of metformin use in patients with decreased kidney function and suggest no worse impacts of PI revision in Japan, indicating no further safety concerns on metformin use in patients with moderately decreased kidney function under the situation with careful use and safety monitoring of metformin

    Integration and Diffusion in Sustainable Development Goals: Learning from the Past, Looking into the Future

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    One of the next major challenges for research and policy on sustainability is setting the post-2015 Development Agenda. This challenge arises as a direct result of the formal ending of the Millennium Development Goals (MDGs) in 2015 and as an outcome of the 2012 United Nations Conference on Sustainable Development (Rio+20). The post-2015 Development Agenda is expected to include two agendas: one on human well-being to advance the MDG targets and the other on planetary well-being, which requires a safe "operating space" within the Earth\u27s life-support system. In contrast to the MDGs, the Sustainable Development Goals (SDGs) are meant to apply to both developing and developed countries and create a space for development within the stable functioning of the Earth\u27s systems. However, what might this all look like? For answers, this paper reviews the achievements and reflections of the MDGs to date and identifies new challenges entailed in the shift of development goals from "millennium" to "sustainable". While most of the existing studies look at these two sets of issues separately, combining the two reveals two important features of the SDGs. First, SDGs need to integrate both human and planetary well-being in a goal, and second, goals, or sub-goals, need to be formulated at multiple levels, from global to local levels. While the MDGs represented no integrated goals, some of the existing proposals on SDGs include integrated goals. However, our analysis has shown that they do not present the vertical diffusion of goals. Considering both integration and diffusion in the architecture of SDGs is a remaining task

    Formation of Porous Intermetallic Thick Film by Ni-Al Microscopic Reactive Infiltration

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    Microporous structures of nickel-aluminide thick films lining the inner wall of microchannels have been investigated. The microchannels were produced in metal bodies by a powder metallurgical process utilizing microscopic reactive infiltration. In the experiment, a nickel-powder compact containing shaped aluminum wires was sintered at a temperature between the melting points of nickel and aluminum. Infiltration and diffusion of aluminum into the surrounding nickel powder, accompanied by the reaction between the metals, occurred during the sintering and brought about the formation of microchannels lined with a NiAl intermetallic layer. In this process, nickel powder composed the device body, and the aluminum wires gave the shape of the microchannels. The intermetallic layer had a microporous structure when the diameter of the aluminum wire was 500 μm and the porosity of the compact specimen was 23.6–31.5% within the porosity range examined. When the porosity was 36.0%, such a structure, the porous thick film, was not observed. On the other hand, the porous NiAl thick film was produced in all specimens with an aluminum wire of 200 μm in diameter. The voidage of the porous thick film was maximized when the porosity of the compact specimen was 29.8%, and it reached to 53.8% in the case the diameter of the aluminum wire was 500 μm, and 60.2% in the case that was 200 μm
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