57 research outputs found

    Mitochondrial nutrients improve immune dysfunction in the type 2 diabetic Goto-Kakizaki rats.

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    The development of type 2 diabetes is accompanied by decreased immune function and the mechanisms are unclear. We hypothesize that oxidative damage and mitochondrial dysfunction may play an important role in the immune dysfunction in diabetes. In the present study, we investigated this hypothesis in diabetic Goto-Kakizaki rats by treatment with a combination of four mitochondrial-targeting nutrients, namely, R-alpha-lipoic acid, acetyl-L-carnitine, nicotinamide and biotin. We first studied the effects of the combination of these four nutrients on immune function by examining cell proliferation in immune organs (spleen and thymus) and immunomodulating factors in the plasma. We then examined, in the plasma and thymus, oxidative damage biomarkers, including lipid peroxidation, protein oxidation, reactive oxygen species, calcium and antioxidant defence systems, mitochondrial potential and apoptosis-inducing factors (caspase 3, p53 and p21). We found that immune dysfunction in these animals is associated with increased oxidative damage and mitochondrial dysfunction and that the nutrient treatment effectively elevated immune function, decreased oxidative damage, enhanced mitochondrial function and inhibited the elevation of apoptosis factors. These effects are comparable to, or greater than, those of the anti-diabetic drug pioglitazone. These data suggest that a rational combination of mitochondrial-targeting nutrients may be effective in improving immune function in type 2 diabetes through enhancement of mitochondrial function, decreased oxidative damage, and delayed cell death in the immune organs and blood

    Synchronous and subsynchronous vibration under the combined effect of bearings and seals: numerical simulation and its experimental validation

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    A three-dimensional computational fluid dynamics (CFD) model of a labyrinth seal was established in order to investigate the influence mechanism of combined effects between bearings and labyrinth seals on the dynamic characteristics of the rotor-bearing-seal system. The dynamic coefficients of the labyrinth seal for various rotating speeds were calculated. Results show that the absolute values of cross-coupled coefficients increase with the increasing rotating speed, while the absolute values of direct coefficients decrease slightly. The positive preswirl at the inlet tends to intensify the increase of cross-coupled coefficients and the decrease of direct coefficients. The negative preswirl shows the opposite effect. A finite element model was further setup. Results show that the labyrinth seal has a large influence on the synchronous response of rotor in the resonant region due to its damping effect. For other speeds, it has a minor effect. The labyrinth seal may promote the instability of the rotor-bearing-seal system. The subsynchronous vibration increases significantly when the seal force is taken into account. The system stability can be generally enhanced by introducing the negative preswirl at the inlet. Results also show that the detrimental influence of the labyrinth seal can be compensated by using suitable bearings. A proper bearing configuration can be designed to reduce the risks of rotordynamic instabilities due to seals. An experimental test was finally performed, and it shows good agreements with the numerical simulation

    Synchronous and subsynchronous vibration under the combined effect of bearings and seals: numerical simulation and its experimental validation

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    A three-dimensional computational fluid dynamics (CFD) model of a labyrinth seal was established in order to investigate the influence mechanism of combined effects between bearings and labyrinth seals on the dynamic characteristics of the rotor-bearing-seal system. The dynamic coefficients of the labyrinth seal for various rotating speeds were calculated. Results show that the absolute values of cross-coupled coefficients increase with the increasing rotating speed, while the absolute values of direct coefficients decrease slightly. The positive preswirl at the inlet tends to intensify the increase of cross-coupled coefficients and the decrease of direct coefficients. The negative preswirl shows the opposite effect. A finite element model was further setup. Results show that the labyrinth seal has a large influence on the synchronous response of rotor in the resonant region due to its damping effect. For other speeds, it has a minor effect. The labyrinth seal may promote the instability of the rotor-bearing-seal system. The subsynchronous vibration increases significantly when the seal force is taken into account. The system stability can be generally enhanced by introducing the negative preswirl at the inlet. Results also show that the detrimental influence of the labyrinth seal can be compensated by using suitable bearings. A proper bearing configuration can be designed to reduce the risks of rotordynamic instabilities due to seals. An experimental test was finally performed, and it shows good agreements with the numerical simulation

    Comprehensive Fractal Description of Porosity of Coal of Different Ranks

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    We selected, as the objects of our research, lignite from the Beizao Mine, gas coal from the Caiyuan Mine, coking coal from the Xiqu Mine, and anthracite from the Guhanshan Mine. We used the mercury intrusion method and the low-temperature liquid nitrogen adsorption method to analyze the structure and shape of the coal pores and calculated the fractal dimensions of different aperture segments in the coal. The experimental results show that the fractal dimension of the aperture segment of lignite, gas coal, and coking coal with an aperture of greater than or equal to 10 nm, as well as the fractal dimension of the aperture segment of anthracite with an aperture of greater than or equal to 100 nm, can be calculated using the mercury intrusion method; the fractal dimension of the coal pore, with an aperture range between 2.03 nm and 361.14 nm, can be calculated using the liquid nitrogen adsorption method, of which the fractal dimensions bounded by apertures of 10 nm and 100 nm are different. Based on these findings, we defined and calculated the comprehensive fractal dimensions of the coal pores and achieved the unity of fractal dimensions for full apertures of coal pores, thereby facilitating, overall characterization for the heterogeneity of the coal pore structure

    A comprehensive insight into the effects of acidification on varied-sized pores in different rank coals

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    Elucidating the evolution law of coal pore structure under acidification is crucial for guiding the practical application of acidizing technology and improving the production of coalbed methane. To comprehensively investigate the influence of acidification on varied-sized pores in different rank coals, in this study, fat coal, meagre coal and anthracite coal were collected and acidified with a mixed solution composed of hydrochloric acid (9 wt%) and hydrofluoric acid (3 wt%). An approach integrating low-pressure CO2 adsorption (LPGA-CO2), low-temperature N2 adsorption (LTGA-N2) and Mercury intrusion porosimetry (MIP) was adopted to fully characterize the varied-sized pore structure before and after acidification to eliminate the limitations of single method. The results demonstrated that acid treatment improved the pore opening degree and connectivity in coal, but had essentially no effect on the pore shape. After acidification, all the coal samples showed significant increases in the porosity and total pore volume, which was mainly contributed by the numerous newly formed large mesopores and macropores, especially the macropores (with an average contribution rate of 74.59%). Taken as a whole, acid treatment had the largest impact on macropores, followed by mesopores, and the smallest impact on micropores. In addition, the variation trend of total specific surface area (SSA) under acidification was primarily determined by micropores. For the three different rank coals selected in this study, the total SSA of fat coal (PM) was more easily affected by acidification and had the largest percentage increase after acid treatment, followed by anthracite coal (YM), while that of meagre coal (LA) decreased slightly. This difference was driven primarily by the different variation trend of micropore SSA in different rank coals. After acidification, the SSA of ultra-micropores and super-micropores all increased in fat coal (PM) and anthracite coal (YM), whereas for meagre coal (LA), although ultra-micropores SSA increased, super-micropores SSA decreased, which ultimately led to the slight decrease of its micropore SSA. Moreover, the total pore volume increment of coal was closely related to the macropore volume increment under acidification, but not significantly related to the coal maturity,which might indicate that, compared with coal rank, the mineral content in coal might be a more important consideration when measuring the applicability of acidification technology

    On-chip Single Nanoparticle Detection and Sizing by Mode Splitting in an Ultra-high-Q Microresonator

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    The ability to detect and size individual nanoparticles with high resolution is crucial to understanding behaviours of single particles and effectively using their strong size-dependent properties to develop innovative products. We report real-time, in-situ detection and sizing of single nanoparticles, down to 30 nm in radius, using mode-splitting in a monolithic ultra-high-Q whispering-gallery-mode (WGM) microtoroid resonator. Particle binding splits a WGM into two spectrally shifted resonance modes, forming a self-referenced detection scheme. This technique provides superior noise suppression and enables extracting accurate size information in a single-shot measurement. Our method requires neither labelling of the particles nor apriori information on their presence in the medium, providing an effective platform to study nanoparticles at single particle resolution.Comment: 23 pages, 8 figure

    Association of platelet-to-lymphocyte ratio and neutrophil-to-lymphocyte ratio with outcomes in stroke patients achieving successful recanalization by endovascular thrombectomy

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    ObjectiveSerum inflammatory biomarkers play crucial roles in the development of acute ischemic stroke (AIS). In this study, we explored the association between inflammatory biomarkers including platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), and monocyte-to-lymphocyte ratio (MLR), and clinical outcomes in AIS patients who achieved successful recanalization.MethodsPatients with AIS who underwent endovascular thrombectomy (EVT) and achieved a modified thrombolysis in the cerebral infarction scale of 2b or 3 were screened from a prospective cohort at our institution between January 2013 and June 2021. Data on blood parameters and other baseline characteristics were collected. The functional outcome was an unfavorable outcome defined by a modified Rankin Scale of 3–6 at the 3-month follow up. Other clinical outcomes included symptomatic intracranial hemorrhage (sICH) and 3-month mortality. Multivariable logistic regression analysis was performed to evaluate the effects of PLR, NLR, and MLR on clinical outcomes.ResultsA total of 796 patients were enrolled, of which 89 (11.2%) developed sICH, 465 (58.4%) had unfavorable outcomes at 3 months, and 168 (12.1%) died at the 3-month follow up. After adjusting for confounding variables, a higher NLR (OR, 1.076; 95% confidence interval [CI], 1.037–1.117; p < 0.001) and PLR (OR, 1.001; 95%CI, 1.000–1.003; p = 0.045) were significantly associated with unfavorable outcomes, the area under the receiver operating characteristic curve of NLR and PLR was 0.622 and 0.564, respectively. However, NLR, PLR, and MLR were not independently associated with sICH and 3-month mortality (all adjusted p > 0.05).ConclusionOverall, our results indicate that higher PLR and NLR were independently associated with unfavorable functional outcomes in AIS patients with successful recanalization after EVT; however, the underlying mechanisms are yet to be elucidated

    Coupled Seepage Mechanics Model of Coal Containing Methane Based on Pore Structure Fractal Features

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    The paper applies fractal theory to the structure of fractal coal pores and calculates the fractal dimension and integrated fractal dimension for each pore section >100 nm, 100 nm > d > 5.25 nm, and <2 nm. In the experiment, we performed the full stress–strain-seepage experiment of methane-bearing coal, revealed the deformation–seepage characteristics of methane-bearing coal under load, and deduced the dynamic prediction mechanical model of methane-bearing coal permeability based on pore heterogeneity, followed by practical verification. The results show that the permeability change in methane-bearing coal is an external manifestation of coal pore deformation, and the two are closely related and affected by changes in the effective stress coefficient. The derived fractal-deformation-coupled methane permeability mechanics model based on coal pore heterogeneity has high accuracy, a general expression for the stress–strain-permeability model based on coal heterogeneity is given, and the fractal Langmuir model is verified to be highly accurate (>0.9) and can be used for coal reservoir permeability prediction

    Experimental study on coal seepage characteristics and stress sensitivity

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    Taking No.3 coal seam of Daping Coal Mine in Lu’an Mining Area of Shanxi Province as the research object, the response law of coal permeability to pore pressure and surrounding pressure was systematically explored by using HB-2 type coal rock sample pore permeation adsorption measurement device, and the relationship between the permeability of loaded coal samples and pore pressure and surrounding pressure was quantitatively analyzed. The results show that: the permeability of coal samples under low pore pressure conditions decreases with the increase of pore pressure in accordance with the power function, and the permeability of coal samples is more sensitive when the pore pressure is below the critical value of 1.5 MPa; the permeability of coal samples under constant pore pressure conditions decreases with the increase of surrounding pressure in a power function, and the permeability decreases significantly, more than 85%; the change of stress in coal reservoir will produce more than 50% irreversible damage to coal permeability. The overall trend of the permeability decay rate during unloading of the coal body with the increase of the surrounding pressure is a downward decay law, and its local variation is characterized by fluctuations of more than one extreme value
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