5,177 research outputs found
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Nox2 dependent redox-regulation of microglial response to amyloid-β stimulation and microgliosis in aging
Microglia express constitutively a Nox2 enzyme that is involved in neuroinflammation by the
generation of reactive oxygen species (ROS). Amyloid β (Aβ) plays a crucial role in Alzheimer’s disease.
However, the mechanism of Aβ-induced microglial dysfunction and redox-regulation of microgliosis
in aging remains unclear. In this study, we examined Nox2-derived ROS in mediating microglial
response to Aβ peptide 1–42 (Aβ42) stimulation in vitro, in aging-associated microgliosis in vivo and in
post-mortem human samples. Compared to controls, Aβ42 markedly induced BV2 cell ROS production,
Nox2 expression, p47phox and ERK1/2 phosphorylation, cell proliferation and IL-1β secretion. All
these changes could be inhibited to the control levels in the presence of Nox2 inhibitor or superoxide
scavenger. Compared to young (3–4 months) controls, midbrain tissues from wild-type aging mice (20–
22 months) had significantly higher levels of Nox2-derived ROS production, Aβ deposition, microgliosis
and IL-1β production. However, these aging-related changes were reduced or absent in Nox2 knockout
aging mice. Clinical significance of aging-associated Nox2 activation, microgliosis and IL-1β production
was investigated using post-mortem midbrain tissues of humans at young (25–38 years) and old age
(61–85 years). In conclusion, Nox2-dependent redox-signalling is crucial in microglial response to Aβ42
stimulation and in aging-associated microgliosis and brain inflammation
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Studying biological science does not lead to adoption of a healthy lifestyle
Aims:
The lifestyle and physical activity (PA) habits of young people play a key role in the prevention of cardiovascular and metabolic diseases at older ages. The current generation of biological science students at university holds promise for better future medicine and medical technology. However, their physical fitness and lifestyle are often ignored.
Methods:
Lifestyle, PAs and common risk factors for cardiovascular disease before, and at, university were collected from 408 students using self-completed, anonymous surveys between the academic years of 2017 and 2019 from the School of Biological Sciences, University of Reading. Statistical analysis was performed using SAS® 9.4 software.
Results:
Among the 408 participants, 134 were male and 274 were female with a mean (SD) age of 19.6 (2.24). Approximately 19% of participants consumed alcohol beyond the safe limit of <14 units/week (112 g/week). Among them, 65% were males. Before university, 47% of students failed to meet the UK National Physical Activity Guidelines (NPAG) which increased to 56% during university with males exhibiting a steeper incline. Compared to their lifestyles before university, more students had insufficient sleep and displayed greater sedentariness during university. Moreover, 16% of students declared no engagement in PA which was greater than the value of 12% before university. Fitness perceptions worsened by 11% during university particularly for females. Statistical analysis revealed that gender, BMI and fitness perceptions were significantly correlated with PA levels. The most prevalent explanation for inadequacy in meeting NPAG was insufficient time.
Conclusion:
Compared to their pre-university lifestyles, biological science students at university are more likely to adopt unhealthier behaviours with less time for exercise and prolonged sedentary behaviours, which increases the risk for cardiovascular diseases. It is important to raise awareness of their fitness perceptions and to encourage health-promoting programmes at university
Fermionic phase transition induced by the effective impurity in holography
We investigate the holographic fermionic phase transition induced by the
effective impurity in holography, which is introduced by massless scalar fields
in Einstein-Maxwell-massless scalar gravity. We obtain a phase diagram in
plane separating the Fermi liquid phase and the non-Fermi liquid
phase.Comment: 17 pages, 9 figure
Machine Directional Register System Modeling for Shaft-Less Drive Gravure Printing Machines
In the latest type of gravure printing machines referred to as the shaft-less drive system, each gravure printing roller is driven by an individual servo motor, and all motors are electrically synchronized. The register error is regulated by a speed difference between the adjacent printing rollers. In order to improve the control accuracy of register system, an accurate mathematical model of the register system should be investigated for the latest machines. Therefore, the mathematical model of the machine directional register (MDR) system is studied for the multicolor gravure printing machines in this paper. According to the definition of the MDR error, the model is derived, and then it is validated by the numerical simulation and experiments carried out in the experimental setup of the four-color gravure printing machines. The results show that the established MDR system model is accurate and reliable
USCID fourth international conference
Presented at the Role of irrigation and drainage in a sustainable future: USCID fourth international conference on irrigation and drainage on October 3-6, 2007 in Sacramento, California.Includes bibliographical references.Studying the impact of microtopography on irrigation performance is important for improving the management of basin irrigation systems. However, the limitation of field experiments will restrict the studies on the impact of microtopography spatial variability on basin irrigation performance. Thus, firstly this paper analyzed the spatial variability characteristics of field-measured Surface Relative Elevations (SRE). The correlations between the field geometry parameters and the spatial variability characteristics of SRE were evaluated, and the estimation methods for parameters of the semi-variogram of SRE were determined. Secondly, a microtopography stochastic generating model was built up based on the Monte-Carlo and the Kriging interpolation techniques. Lastly, the effect of spatial variability of microtopography on the performance of basin irrigation was evaluated by using of the numerical simulation model. Results showed that the microtopography undulation degree and the spatial distribution difference of undulation location had obvious effect on the basin irrigation performance. The average irrigation depth (Z'avg), corresponding to the water just cover the whole basin surface is increased while the irrigation application efficiency (Ea) and the irrigation uniformity (CU) is decreased when the field elevation non-uniformity, measured by the standard deviation of SRE (Sd) is increased. The effect of spatial distribution of undulation location on the irrigation performance was dependent upon the microtopography undulation degree, when Sd is less than 2cm the impacts can be neglected, while Sd is greater than 2cm, the influence should be considered
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