356 research outputs found

    Indonesian earthquake: Earthquake risk from co-seismic stress.

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    Following the massive loss of life caused by the Sumatra-Andaman earthquake in Indonesia and its tsunami, the possibility of a triggered earthquake on the contiguous Sunda trench subduction zone is a real concern. We have calculated the distributions of co-seismic stress on this zone, as well as on the neighbouring, vertical strike-slip Sumatra fault, and find an increase in stress on both structures that significantly boosts the already considerable earthquake hazard posed by them. In particular, the increased potential for a large subduction-zone event in this region, with the concomitant risk of another tsunami, makes the need for a tsunami warning system in the Indian Ocean all the more urgent.John McCloskey, Suleyman S.Nalbant, Sandy Steac

    Near-field propagation of tsunamis from megathrust earthquakes

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    We investigate controls on tsunami generation and propagation in the near-field of great megathrust earthquakes using a series of numerical simulations of subduction and tsunamigenesis on the Sumatran forearc. The Sunda megathrust here is advanced in its seismic cycle and may be ready for another great earthquake. We calculate the seafloor displacements and tsunami wave heights for about 100 complex earthquake ruptures whose synthesis was informed by reference to geodetic and stress accumulation studies. Remarkably, results show that, for any near-field location: (1) the timing of tsunami inundation is independent of slipdistribution on the earthquake or even of its magnitude, and (2) the maximum wave height is directly proportional to the vertical coseismic displacement experienced at that location. Both observations are explained by the dominance of long wavelength crustal flexure in near-field tsunamigenesis. The results show, for the first time, that a single estimate of vertical coseismic displacement might provide a reliable short-term forecast of the maximum height of tsunami waves

    Validation of a small cough detector

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    Research question The assessment of cough frequency in clinical practice relies predominantly on the patient's history. Currently, objective evaluation of cough is feasible with bulky equipment during a brief time (i.e., hours up to one day). Thus, monitoring of cough has been rarely performed outside clinical studies. We developed a small wearable cough detector (SIVA-P3) that uses deep neural networks for the automatic counting of coughs. This study examined the performance of the SIVA-P3 in an outpatient setting. Methods We recorded cough epochs with SIVA-P3 over eight consecutive days in patients suffering from chronic cough. During the first 24 h, the detector was validated against cough events counted by trained human listeners. The wearing comfort and the device usage were assessed by a questionnaire. Results In total, 27 participants (50±14 years) with either chronic unexplained cough (n=12), COPD (n=4), asthma (n=5) or interstitial lung disease (n=6) were studied. During the daytime, the sensitivity of SIVA-P3 cough detection was 88.5±2.49%, and the specificity was 99.97±0.01%. During the night-time, the sensitivity was 84.15±5.04% and the specificity was 99.97±0.02%. The wearing comfort and usage of the device was rated as very high by most participants. Conclusion SIVA-P3 enables automatic continuous cough monitoring in an outpatient setting for objective assessment of cough over days and weeks. It shows comparable or higher sensitivity than other devices with fully automatic cough counting. Thanks to its wearing comfort and the high performance for cough detection, it has the potential for being used in routine clinical practice

    Monocytes regulate the mechanism of T-cell death by inducing Fas-mediated apoptosis during bacterial infection.

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    Monocytes and T-cells are critical to the host response to acute bacterial infection but monocytes are primarily viewed as amplifying the inflammatory signal. The mechanisms of cell death regulating T-cell numbers at sites of infection are incompletely characterized. T-cell death in cultures of peripheral blood mononuclear cells (PBMC) showed 'classic' features of apoptosis following exposure to pneumococci. Conversely, purified CD3(+) T-cells cultured with pneumococci demonstrated necrosis with membrane permeabilization. The death of purified CD3(+) T-cells was not inhibited by necrostatin, but required the bacterial toxin pneumolysin. Apoptosis of CD3(+) T-cells in PBMC cultures required 'classical' CD14(+) monocytes, which enhanced T-cell activation. CD3(+) T-cell death was enhanced in HIV-seropositive individuals. Monocyte-mediated CD3(+) T-cell apoptotic death was Fas-dependent both in vitro and in vivo. In the early stages of the T-cell dependent host response to pneumococci reduced Fas ligand mediated T-cell apoptosis was associated with decreased bacterial clearance in the lung and increased bacteremia. In summary monocytes converted pathogen-associated necrosis into Fas-dependent apoptosis and regulated levels of activated T-cells at sites of acute bacterial infection. These changes were associated with enhanced bacterial clearance in the lung and reduced levels of invasive pneumococcal disease

    PyK2 and FAK connections to p190Rho guanine nucleotide exchange factor regulate RhoA activity, focal adhesion formation, and cell motility

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    Integrin binding to matrix proteins such as fibronectin (FN) leads to formation of focal adhesion (FA) cellular contact sites that regulate migration. RhoA GTPases facilitate FA formation, yet FA-associated RhoA-specific guanine nucleotide exchange factors (GEFs) remain unknown. Here, we show that proline-rich kinase-2 (Pyk2) levels increase upon loss of focal adhesion kinase (FAK) in mouse embryonic fibroblasts (MEFs). Additionally, we demonstrate that Pyk2 facilitates deregulated RhoA activation, elevated FA formation, and enhanced cell proliferation by promoting p190RhoGEF expression. In normal MEFs, p190RhoGEF knockdown inhibits FN-associated RhoA activation, FA formation, and cell migration. Knockdown of p190RhoGEF-related GEFH1 does not affect FA formation in FAK−/− or normal MEFs. p190RhoGEF overexpression enhances RhoA activation and FA formation in MEFs dependent on FAK binding and associated with p190RhoGEF FA recruitment and tyrosine phosphorylation. These studies elucidate a compensatory function for Pyk2 upon FAK loss and identify the FAK–p190RhoGEF complex as an important integrin-proximal regulator of FA formation during FN-stimulated cell motility

    Существует ли связь между средним уровнем mIDkIne и прогнозом заболевания COVID-19?

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       The objective was aimed to measure plasma midkine (MK)* levels in patients with COVID-19 and assess its clinical significance.   Materials and Methods. 88 patients observed in our hospital with a diagnosis of COVID-19 were included in the study. The patients’ demographic characteristics, clinical, and laboratory data were studied, and the relationship between MK levels, prognosis, and other parameters was investigated.   Results. Of the 88 patients included in the study, 43 (48.9 %) were female and 45 (51.1%) were male. 24 (27%) patients died. The mean age of non-survivors was 70 ± 12.3 years and the survivors were 61.9 ± 18.2 years. Mortality predictors such as D-dimer, ferritin, troponin, LDH, CRP, and procalcitonin were significantly higher in non-survivors than in survivors (p < 0.05). The median MK level (IR) was 152.5 ± 125 pg/ml in all patients, 143 ± 149 pg/ml in survivors, and 165.5 ± 76 pg/ml in non-survivors (p = 0.546). The difference between these two groups was not statistically significant. The area under the ROC curve was found to be 0.542 (95% CI 0.423–0.661, p = 0.546).   Conclusion. MK is not a biomarker that can replace or reinforce known predictors of mortality in COVID-19 patients.   Цель. Исследование направлено на измерение уровня Midkine (MK)* в плазме крови у пациентов с COVID-19 и оценку его клинической значимости.   Материалы и методы. В исследование включены 88 пациентов, наблюдавшихся в клинике с диагнозом COVID-19. Изучены демографические характеристики пациентов, клинические и лабораторные данные, а также исследована взаимосвязь между уровнями MK, прогнозом и другими параметрами.   Результаты. Из 88 пациентов, включенных в исследование, 43 (48,9 %) были женщинами и 45 (51,1 %) – мужчинами. 24 (27 %) пациента умерли. Средний возраст невыживших составил 70 ± 12,3 года, а выживших – 61,9 ± 18,2 года. Предикторы смертности, такие как D-димер, ферритин, тропонин, ЛДГ, СРБ и прокальцитонин, были значительно выше у умерших, чем у выживших (р < 0,05). Медиана уровня МК (IR) составила 152,5 ± 125 пг/мл у всех пациентов, 143 ± 149 пг/мл у выживших и 165,5 ± 76 пг/мл у умерших (р = 0,546). Разница между этими 2 группами была незначима. Было обнаружено, что площадь под кривой ROC составляет 0,542 (95 % ДИ 0,423–0,661, р = 0,546).   Вывод. МК не является биомаркером, который может заменить или усилить известные предикторы смертности у пациентов с COVID-19

    Effect of cooling methods on dimensional accuracy and surface finish of a turned titanium part

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    In metal cutting, the choice of cooling method influences the deformation mechanism, which is related to the dimensional accuracy and surface finish of the parts. The deformation mechanism of titanium alloys under machining conditions is known to be very different from that of commonly used industrial materials. Therefore, the effect of cooling methods on dimensional accuracy and surface finish in machining titanium is of particular interest. This paper investigates experimentally and analytically the influence of cooling method and cutting parameters on two major dimensional accuracy characteristics of a turned titanium part—diameter error and circularity, and surface finish. Data were analyzed via three methods: traditional analysis, Pareto ANOVA, and Taguchi method. The findings indicate that the cooling method has significant effect on circularity error (contribution ratio 76.75 %), moderate effect on diameter error (contribution ratio 25.00 %), and negligible effect on surface finish (contribution ratio 0.16 %)

    Spatial control of Cdc42 signalling by a GM130-RasGRF complex regulates polarity and tumorigenesis

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    The small GTPase Cdc42 is a key regulator of polarity, but little is known in mammals about its spatial regulation and the relevance of spatial Cdc42 pools for polarity. Here we report the identification of a GM130-RasGRF complex as a regulator of Cdc42 at the Golgi. Silencing GM130 results in RasGRF-dependent inhibition of the Golgi pool of Cdc42, but does not affect Cdc42 at the cell surface. Furthermore, active Cdc42 at the Golgi is important to sustain asymmetric front-rear Cdc42-GTP distribution in directionally migrating cells. Concurrent to Cdc42 inhibition, silencing GM130 also results in RasGRF-dependent Ras-ERK pathway activation. Moreover, depletion of GM130 is sufficient to induce E-cadherin downregulation, indicative of a loss in cell polarity and epithelial identity. Accordingly, GM130 expression is frequently lost in colorectal and breast cancer patients. These findings establish a previously unrecognized role for a GM130-RasGRF-Cdc42 connection in regulating polarity and tumorigenesis
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