Analysis and numerical simulation on parameter optimization of low hardness coal pre-splitting blasting

In view of the characteristics of low coal hardness and permeability of a certain area, in order to confirm suitable cartridge radius and non-coupling charging coefficient, and improve coal blasting efficiency in the area, software of ANSYS/LS_DYNA was used for simulation analysis of blast cracking, and radius of compression zone and the maximum crack length under different cartridge radius and non-coupling charging coefficient were obtained. The analysis results show that the most suitable cartridge radius is 30 mm, and the non-coupling charging coefficient is 1.5 when the coal is on the pre-splitting blasting anti-reflection; in a certain range, blast cracking effect of high hardness coal is better than low hardness coal, the main performance is that for the high hardness coal, coal crushing area radius is relatively small and cracks number is more than low hardness coal, while the crack length is also large

Characteristics of Desertification and Short-Term Effectiveness of Differing Treatments on Shifting Sand Dune Stabilization in an Alpine Rangeland

Rangeland desertification is one of the most serious problems threatening the ecological environment and socio-economic development on the eastern Qinghai-Tibet Plateau in China. To combat desertification and reduce its adverse effects, some strategies have been undertaken to stabilize the mobile sand dunes and restore the desertified land. In this study, rangeland desertification with a gradient degree of none, light, medium, severe and extreme was assessed, and short-term effectiveness of different treatments on stabilizing the shifting sand dunes was evaluated by monitoring selected vegetation and soil properties. Results showed that vegetation became thinner and sparser, and soil environment deteriorated significantly under desertification, leading to a poor and low diversity ecosystem. Applying a checkerboard protection strategy in which herb species were planted and using a shrub vegetation planting method without checkerboard protection on mobile dunes for five years, vegetation growth state and soil properties were improved. Soil particles were finer, vegetation restoration was more rapid, and soil nutrient improvement was more apparent at the lower locations of the sand dunes under the checkerboard protection planted with herbs, which performed slightly better in improving soil properties than the shrub planting method alone. A longer time period would be required for vegetation and soils on the sand dunes to be restored to sustain more intensive land use. These findings provide more insight into dune stabilization, allowing effective management in the ecological restoration of desertified rangeland

Characteristics of fecal mercury and methylmercury and risks to captive golden snub-nosed monkeys (Rhinopithecus roxellana) and rhesus macaques (Macaca mulatta) in China

Environmental pollution is widespread and poses significant risks to both human populations and diverse animal species. As part of conservation initiatives, many endangered animals are housed in zoos and breeding centers close to human activities, potentially exposing them to health threats arising from environmental contamination, such as mercury (Hg). By analyzing non-invasive fecal samples from 13 Chinese zoos, we assessed total mercury (THg) and methylmercury (MeHg) exposure in two non-human primate species: the endangered species golden snub-nosed monkey (Rhinopithecus roxellana), and the most widely distributed rhesus macaque (Macaca mulatta). The concentration of THg in golden snub-nosed monkeys (mean ± s.d.: 76.7 ± 35.6 ng/g; median: 71.8 ng/g, range: 11.2–200.0 ng/g, n = 71) was significantly higher than that in rhesus macaques (mean ± s.d.: 32.3 ± 54.7 ng/g; median: 17.5 ng/g, range: 7.4–409.0 ng/g, n = 98). No significant differences were observed in both MeHg and MeHg % between these two species. Age and sex did not predict fecal Hg. Among adults, approximately 85 % of sampled individuals exhibited hazard quotient (HQ) values exceeding 1, indicating mercury poses a health risk to captive primate populations. The average HQ for golden snub-nosed monkeys was 2.98 ± 1.68 (range: 0.46–8.21, n = 43), while for rhesus macaques was 1.84 ± 1.64 (range: 0.61–12.49, n = 71). Our findings suggest that conservation efforts for captive primates may be compromised by Hg pollution, particularly in golden snub-nosed monkeys. Further investigation and ongoing biomonitoring from an ecotoxicological perspective, are crucial to ensuring the health of captive primate populations

Dexmedetomidine Acts via the JAK2/STAT3 Pathway to Attenuate Isoflurane-Induced Neurocognitive Deficits in Senile Mice

<div><p>Background</p><p>Previous studies showed that isoflurane-induced cognitive deficits could be alleviated by dexmedetomidine in young animal subjects. In the current study, we examine whether dexmedetomidine could also alleviate isoflurane-induced cognitive deficits in senile animals.</p><p>Methods</p><p>Senile male C57BL/6 mice (20 months) received dexmedetomidine (50 μg/kg, i.p.) or vehicle 30 minutes prior to isoflurane exposure (1.3% for 4 h). Cognitive function was assessed 19 days later using a 5-day testing regimen with Morris water maze. Some subjects also received pretreatment with α₂ adrenoreceptor antagonist atipamezole (250 μg/kg, i.p.), JAK2 inhibitor AG490 (15 mg/kg i.p.) or STAT3 inhibitor WP1066 (40 mg/kg i.p.) 30 minutes prior to dexmedetomidine.</p><p>Results</p><p>Isoflurane exposure increased and reduced the time spent in the quadrant containing the target platform in training sessions. The number of crossings over the original target quadrant was also decreased. Dexmedotomidine attenuated such effects. Effects of dexmedotomidine were reduced by pretreatment with atipamezole, AG490 and WP1066. Increased phosphorylation of JAK2 and STAT3 in the hippocampus induced by isoflurane was augmented by dexmedetomidine. Effects of dexmedetomidine on JAK2/STAT3 phosphorylation were attenuated by atipamezole, AG490 and WP1066. Isoflurane promoted neuronal apoptosis and increased the expression of cleaved caspase-3 and BAD, and reduced Bcl-2 expression. Attenuation of such effects by dexmedotomidine was partially blocked by atipamezole, AG490 and WP1066.</p><p>Conclusion</p><p>Dexmedetomidine could protect against isoflurane-induced spatial learning and memory impairment in senile mice by stimulating the JAK2/STAT3 signaling pathway. Such findings encourage the use of dexmedetomidine in geriatric patients receiving isoflurane anesthesia.</p></div

Effects of dexmedetomidine on p-CREB levels and JAK2/STAT3 pathway activation in hippocampus.

<p>Representative Western blots (A) showing levels of JAK2, p-JAK2, STAT3, p-STAT3, CREB, and p-CREB in hippocampus at 19d after animals were treated as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164763#pone.0164763.g002" target="_blank">Fig 2</a>. Densitometry was used to determine ratios of the levels of p-JAK2 to JAK2 (B), p-STAT3 to STAT3 (C), and p-CREB to CREB (D). Data are represented as mean ± SD (n = 8). *<i>P</i> < 0.05 vs. control group; ^#<i>P</i>< 0.05 vs. ISO group; ^&<i>P</i>< 0.05 vs. DEX group.</p

Effects of dexmedetomidine on isoflurane-induced changes in expression of apoptosis-related proteins.

<p>Representative Western blots (A) showing levels of cleaved caspase-3, BAD, Bcl-2 and BDNF in hippocampus at 19d after animals were treated as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0164763#pone.0164763.g002" target="_blank">Fig 2</a>. Levels of caspase-3 (B), BAD (C), Bcl-2 (D) and BDNF (E) were quantitated relative to that of β-actin. Data are represented as mean ± SD (n = 8). *<i>P</i> < 0.05 vs. control group; ^#<i>P</i>< 0.05 vs. ISO group; ^&<i>P</i>< 0.05 vs. DEX group.</p

Analysis of arterial blood gases and blood glucose in senile mice immediately after isoflurane exposure.

<p>Analysis of arterial blood gases and blood glucose in senile mice immediately after isoflurane exposure.</p