Analysis of fatigue delamination growth for piezoelectric laminated cylindrical shell considering nonlinear contact effect

AbstractThis paper presents a nonlinear analysis model of fatigue delamination growth for piezoelectric laminated cylindrical shells with asymmetric laminations. Considering the geometric nonlinearity and the nonlinear contact effect, the nonlinear governing equations and corresponding matching conditions for the delaminated shells are established by using the movable-boundary variational principle. According to the Griffith criterion and Paris law, the energy release rate and delamination growth rate along the delamination front are determined. Then, using cyclic skip method, the delamination growth lengths are derived. In numerical examples, the effects of the voltages, stiffness factor of contact region, asymmetry of delamination and delamination length on energy rate and delamination growth length are discussed

Role of Selective Histone Deacetylase 6 Inhibitor ACY-1215 in Cancer and Other Human Diseases

The deacetylation process regulated by histone deacetylases (HDACs) plays an important role in human health and diseases. HDAC6 belongs to the Class IIb of HDACs family, which mainly modifies non-histone proteins located in the cytoplasm. HDAC6 plays a key role in tumors, neurological diseases, and inflammatory diseases. Therefore, targeting HDAC6 has become a promising treatment strategy in recent years. ACY-1215 is the first orally available highly selective HDAC6 inhibitor, and its efficacy and therapeutic effects are being continuously verified. This review summarizes the research progress of ACY-1215 in cancer and other human diseases, as well as the underlying mechanism, in order to guide the future clinical trials of ACY-1215 and more in-depth mechanism researches

Key problems in in-situ pyrolysis of tar-rich coal drilling for extraction of coal-based oil and gas resources

Tar-rich coal is a special coal resource with the property of oil and gas resources. Developing the oil and gas resources contained in the tar-rich coal is of great significance for ensuring energy security and realizing the goal of "dual carbon". In-situ pyrolysis of tar-rich coal is a new coal resource development technology. Through some artificial cracks in coal seams, multiple wells can be connected. The coal seam is then heated using some technologies such as electric heating or fluid heating to generate oil and gas resources from the pyrolysis of tar-rich coal. At present, some problems such as coal seam heating mode, optimal pyrolysis temperature, reservoir reconstruction technology and efficient extraction of pyrolysis oil and gas need to be urgently solved. ① There are some defects in the application of reaction heating, conduction heating, and radiation heating in the underground in-situ heating of tar-rich coal. Convection heating based on injection fluid heating is more suitable for the in-situ heating of tar-rich coal. According to different geological conditions, it is still necessary to carry out targeted research work for optimizing the economical and safe heat carrying fluid and creating an efficient pyrolysis atmosphere. The combination of various heating methods is expected to be the breakthrough direction of the underground in-situ heating method of tar-rich coal. ② At present, 350−450 ℃ is generally recognized as the efficient pyrolysis temperature. With different coal characteristics and different pyrolysis atmospheres, the corresponding dominant pyrolysis temperature range is slightly different. The methods of chemical thermodynamics and kinetics for the pyrolysis of tar-rich coal are effective means to predict pyrolysis temperature scientifically. ③ Hydraulic fracturing, supercritical CO2 fracturing, and liquid nitrogen fracturing have some limitations for the in-situ pyrolysis of tar-rich coal. For different geological conditions, it is necessary to select the appropriate reservoir reconstruction scheme through specific objective evaluation. Controllable shock wave technology has the advantage of high efficiency and control in rock fracturing and is expected to be widely used in the in-situ pyrolysis process in the future. ④ The combustible gases produced by the pyrolysis of tar-rich coal are mainly CH4, H2, and CO, accompanied by a high content of CO2, which is easy to be directly extracted. The oil produced by pyrolysis is coal tar with high density and high viscosity, which will condense in large quantities below 180 ℃. There is a risk of wellbore clogging and the key to improving the extraction efficiency of pyrolysis products is to formulate the temperature and pressure maintenance scheme of the extraction well. In addition, the systematic issues such as integrated geological engineering evaluation, in-situ pyrolysis reaction process monitoring, and the whole-process numerical simulation of tar-rich coal should also be focused on in the future research work

Disentangling the effects of vapor pressure deficit on northern terrestrial vegetation productivity

The impact of atmospheric vapor pressure deficit (VPD) on plant photosynthesis has long been acknowledged, but large interactions with air temperature (T) and soil moisture (SM) still hinder a complete understanding of the influence of VPD on vegetation production across various climate zones. Here, we found a diverging response of productivity to VPD in the Northern Hemisphere by excluding interactive effects of VPD with T and SM. The interactions between VPD and T/SM not only offset the potential positive impact of warming on vegetation productivity but also amplifies the negative effect of soil drying. Notably, for high-latitude ecosystems, there occurs a pronounced shift in vegetation productivity\u27s response to VPD during the growing season when VPD surpasses a threshold of 3.5 to 4.0 hectopascals. These results yield previously unknown insights into the role of VPD in terrestrial ecosystems and enhance our comprehension of the terrestrial carbon cycle\u27s response to global warming

Proteomic analysis of differential proteins in pancreatic carcinomas: Effects of MBD1 knock-down by stable RNA interference

<p>Abstract</p> <p>Background</p> <p>Methyl-CpG binding domain protein 1 (MBD1), a suppressor of gene transcription, may be involved in inactivation of tumor suppressor genes during tumorigenesis. Over-expression of MBD1 has been reported in human pancreatic carcinomas.</p> <p>Methods</p> <p>In this study, we established a MBD1-knock-down pancreatic cancer cell line (BxPC-3) using stable RNA interference, to compare the proteomic changes between control and MBD1-knock-down cells using two-dimensional gel electrophoresis and mass spectrometry.</p> <p>Results</p> <p>We identified five proteins that were up-regulated and nine proteins that were down-regulated. Most of the identified proteins are involved in tumorigenesis, some are prognostic biomarkers for human malignant tumors.</p> <p>Conclusion</p> <p>Our data suggest that these differential proteins may be associated with the function of MBD1, and provide some insight into the functional mechanism of MBD1 in the development of pancreatic cancer.</p

Association of inpatient use of angiotensin converting enzyme inhibitors and angiotensin II receptor blockers with mortality among patients with hypertension hospitalized with COVID-19

Rationale: Use of angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs) is a major concern for clinicians treating coronavirus disease 2019 (COVID-19) in patients with hypertension. Objective: To determine the association between in-hospital use of ACEI/ARB and all-cause mortality in COVID-19 patients with hypertension. Methods and Results: This retrospective, multi-center study included 1128 adult patients with hypertension diagnosed with COVID-19, including 188 taking ACEI/ARB (ACEI/ARB group; median age 64 [IQR 55-68] years; 53.2% men) and 940 without using ACEI/ARB (non-ACEI/ARB group; median age 64 [IQR 57-69]; 53.5% men), who were admitted to nine hospitals in Hubei Province, China from December 31, 2019 to February 20, 2020. Unadjusted mortality rate was lower in the ACEI/ARB group versus the non-ACEI/ARB group (3.7% vs. 9.8%; P = 0.01). In mixed-effect Cox model treating site as a random effect, after adjusting for age, gender, comorbidities, and in-hospital medications, the detected risk for all-cause mortality was lower in the ACEI/ARB group versus the non-ACEI/ARB group (adjusted HR, 0.42; 95% CI, 0.19-0.92; P =0.03). In a propensity score-matched analysis followed by adjusting imbalanced variables in mixed-effect Cox model, the results consistently demonstrated lower risk of COVID-19 mortality in patients who received ACEI/ARB versus those who did not receive ACEI/ARB (adjusted HR, 0.37; 95% CI, 0.15-0.89; P = 0.03). Further subgroup propensity score-matched analysis indicated that, compared to use of other antihypertensive drugs, ACEI/ARB was also associated with decreased mortality (adjusted HR, 0.30; 95%CI, 0.12-0.70; P = 0.01) in COVID-19 patients with hypertension. Conclusions: Among hospitalized COVID-19 patients with hypertension, inpatient use of ACEI/ARB was associated with lower risk of all-cause mortality compared with ACEI/ARB non-users. While study interpretation needs to consider the potential for residual confounders, it is unlikely that in-hospital use of ACEI/ARB was associated with an increased mortality risk

Simple Synthesis and Characterization of Hexagonal and Ordered Al–MCM–41 from Natural Perlite

Silica reagents are expensive and toxic for use in the synthesis of mesoporous silica materials. It is imperative to take an interest in green silicon sources. In this paper, we report the synthesis of hexagonal and ordered aluminum-containing mesoporous silica materials (Al&#8722;MCM&#8722;41) from natural perlite mineral without addition of silica or aluminum reagents. A pretreatment process involving acid leaching, alkali leaching, and strongly acidic cation exchange resins treatment was critical to obtain silicon and aluminum sources from natural perlite mineral. The Al&#8722;MCM&#8722;41 material was synthesized via a hydrothermal reaction with hexadecyl trimethyl ammonium bromide (CTAB) as the template and subsequent calcination. The resulting mesophase had a hexagonal and ordered mesoporous structure, confirmed by small-angle X-ray diffraction (SAXRD) and transmission electron microscopy (TEM). Al&#8722;MCM&#8722;41 material had a high Brunauer&#8722;Emmet&#8722;Teller (BET) surface area of 1024 m2/g, pore volume of 0.72 cm3/g and an average pore diameter of 2.8 nm with a pore size distribution centered at 2.5 nm. The thermal behavior of the as-synthesized samples during calcination was investigated by thermogravimetry (TG) and differential thermogravimetry (DTG) analysis. The Al&#8722;MCM&#8722;41 material showed a negative surface charge in aqueous solution with the pH value ranging from 2 to 13. The variations of chemical structures from natural perlite to Al&#8722;MCM&#8722;41 were traced by wide-angle X-ray diffraction (WAXRD) and Fourier-transform infrared spectroscopy (FTIR). A proposed mechanism for the synthesis of hexagonal and ordered mesoporous silica materials from natural perlite is discussed