Three-dimensional petrographical investigations on borehole rock samples: a comparison between X-ray computed- and neutron tomography

Technical difficulties associated with excavation works in tectonized geological settings are frequent. They comprise instantaneous and/or delayed convergence, sudden collapse of gallery roof and/or walls, outpouring of fault-filling materials and water inflows. These phenomena have a negative impact on construction sites and their safety. In order to optimize project success, preliminary studies on the reliability of rock material found on site are needed. This implies in situ investigations (surface mapping, prospective drilling, waterflow survey, etc.) as well as laboratory investigations on rock samples (permeability determination, moisture and water content, mineralogy, petrography, geochemistry, mechanical deformation tests, etc.). A set of multiple parameters are then recorded which permit better insight on site conditions and probable behavior during excavation. Because rock formations are by nature heterogeneous, many uncertainties remain when extrapolating large-scale behavior of the rock mass from analyses of samples order of magnitudes smaller. Indirect large-scale field investigations (e.g. geophysical prospecting) could help to better constrain the relationships between lithologies at depth. At a much smaller scale, indirect analytical methods are becoming more widely used for material investigations. We discuss in this paper X-ray computed tomography (XRCT) and neutron tomography (NT), showing promising results for 3D petrographical investigations of the internal structure of opaque materials. Both techniques record contrasts inside a sample, which can be interpreted and quantified in terms of heterogeneity. This approach has the advantage of combining genetic parameters (physico-chemical rock composition) with geometric parameters resulting from alteration or deformation processes (texture and structure). A critical analysis of such 3D analyses together with the results of mechanical tests could improve predictions of short- and long-term behavior of a rock unit. Indirect methods have the advantage of being non-destructive. However, as it is the case with large-scale geophysical surveying, XRCT and NT are affected by several error factors inherent to the interaction of a radiation modality (X-ray or neutron beam) with the atomic structure of the investigated materials. Recorded signals are therefore in particular cases not artifact-free and need to be corrected in a subsequent stage of data processin

Effect of sequential treatment with syndrome differentiation on acute exacerbation of chronic obstructive pulmonary disease and "AECOPD Risk-Window": study protocol for a randomized placebo-controlled trial

BACKGROUND: Frequent chronic obstructive pulmonary disease (COPD) exacerbation is a major cause of hospital admission and mortality. It has been reported that Traditional Chinese Medicine (TCM) may relieve COPD symptoms and reduce the incidence of COPD exacerbations, thus improving life quality of COPD patients. The acute exacerbation of COPD risk-window (AECOPD-RW) is the period after an exacerbation and before the patient returns to baseline. In the AECOPD-RW, patients are usually at increased risk of a second exacerbation, which may lead to hospital admission and high mortality. It may be beneficial for acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients to receive interventions during AECOPD-RW. During exacerbations the treatment principle is to eliminate exogenous pathogens, whereas the AECOPD-RW treatment principle focuses on enhancing body resistance. METHODS/DESIGN: A prospective, multi-center, single-blinded, double-dummy and randomized controlled clinical trial is being conducted to test the therapeutic effects of a sequential two stage treatment, which includes eliminating pathogen and strengthening vital qi with syndrome differentiation. A total of 364 patients will be enrolled in this study with 182 in each treatment group (TCM and control). Patients received medication (or control) according to their assigned group. TCM for AECOPD were administered twice daily to patients with AECOPD over 7 to 21 days, followed by TCM for AECOPD-RW over 28 days. All patients were followed for six months. The clinical symptoms, the modified medical research council dyspnea (MMRC) scale and exacerbations were used as the primary outcome measures. Pulmonary function, quality of life and mortality rate were used as secondary outcome measures. DISCUSSION: It is hypothesized that sequentially eliminating pathogens and strengthening vital qi treatments with syndrome differentiation will have beneficial effects on reducing the frequency and duration of acute exacerbation, relieving symptoms and improving quality of life for COPD patients. TRIAL REGISTRATION: This study is registered at ClinicalTrials.gov, ChiCTR-TRC-11001460

The patterns and prevention of injuries in college table tennis training

This paper conducts a detailed investigation and analysis of injuries among table tennis athletes from college sports academies, and preliminarily explores some general patterns of sports-related injuries that have occurred, summarizing some preventive measures and solutions

Dynamic load response law and limit of pressure relief drilling for coal seam prevention and control of rock burst

The surrounding rock of the impact hazard roadway is often disturbed by external dynamic loads, which often leads to the occurrence of impact ground pressure. In order to explore the anti impact and pressure relief effects of large-diameter pre relief boreholes in coal seams under dynamic load disturbance conditions, a comprehensive method including theoretical analysis, laboratory experiments, and numerical simulations was used to study the dynamic load response law and limit of coal seam anti impact and pressure relief boreholes. The results indicate that the coal body in the pressure relief zone of large-diameter drilling forms a weak structure, increases the ability to attenuate dynamic loads, and reduces the possibility of impact. Under low dynamic load disturbance, the expansion of pores and cracks, and the cumulative acoustic emission events show an upward trend with the increase of disturbance period; Under higher dynamic load disturbances, the degree of damage and rupture of coal samples in boreholes intensifies, and acoustic emission events are mainly high-energy. As the dynamic load level and disturbance period increase, the distance between the stress concentration zone, elastic high-energy zone and the borehole shortens, the influence range increases, the rock movement trend strengthens, and the degree of elastic energy accumulation increases. Under low dynamic load level disturbances, drilling plays a role in energy dissipation, pressure relief, and anti-collision, which can maintain the stability of the surrounding rock. However, under high-energy dynamic load disturbances, the anti-collision of large-diameter drilling fails, and the drilling wall is prone to dynamic instability and damage, causing instability of the surrounding rock. Overall, large-diameter pressure relief boreholes have weakened structures that can dissipate energy, reduce impact, and lower the degree of dynamic load disturbance. However, under high-energy and high-frequency dynamic load disturbances, the movement trend of the surrounding rock of the pressure relief borehole increases, the degree of fracture response is severe, and the anti impact effectiveness is limited

Airway Relaxation Mechanisms and Structural Basis of Osthole for Improving Lung Function in Asthma

Overuse of β2-adrenoceptor agonist bronchodilators evokes receptor desensitization, decreased efficacy, and an increased risk of death in asthma patients. Bronchodilators that do not target β2-adrenoceptors represent a critical unmet need for asthma management. Here, we characterize the utility of osthole, a coumarin derived from a traditional Chinese medicine, in preclinical models of asthma. In mouse precision-cut lung slices, osthole relaxed preconstricted airways, irrespective of β2-adrenoceptor desensitization. Osthole administered in murine asthma models attenuated airway hyperresponsiveness, a hallmark of asthma. Osthole inhibited phosphodiesterase 4D (PDE4D) activity to amplify autocrine prostaglandin E2 signaling in airway smooth muscle cells that eventually triggered cAMP/PKA-dependent relaxation of airways. The crystal structure of the PDE4D complexed with osthole revealed that osthole bound to the catalytic site to prevent cAMP binding and hydrolysis. Together, our studies elucidate a specific molecular target and mechanism by which osthole induces airway relaxation. Identification of osthole binding sites on PDE4D will guide further development of bronchodilators that are not subject to tachyphylaxis and would thus avoid β2-adrenoceptor agonist resistance

Effects of high light exposure and heterologous expression of β-carotene ketolase on the metabolism of carotenoids in Chlamydomonas reinhardtii

IntroductionStress from high light exposure and overexpression of β-carotene ketolase can have significant effects on the synthesis of carotenoids in Chlamydomonas reinhardtii. As a promising platform for carotenoid production, C. reinhardtii needs further research and technological innovation to address challenges, such as environmental interference, exogenous gene expression, and metabolic regulation, to achieve efficient and sustainable production of carotenoids.MethodsAppropriate β-carotene ketolase were selected from different organisms and subjected for codon optimization based on the preferences of the nuclear genome of C. reinhardtii. After designation, including intron insertion and chloroplast transit peptide, expression vectors were constructed and used for nuclear transformation of C. reinhardtii CC849 by bead milling method. Subsequently, DNA-PCR and RT-PCR were used to identify positive transformants grown with antibiotic stress, LC-MS/MS and metabolic analysis were performed to evaluate the products of transformants.ResultsIn this study, carotenoid metabolism regulation in C. reinhardtii was investigated in a time-dependent manner through high light exposure and heterologous expression of β-carotene ketolase. The results suggested that the stress from high light exposure (500 μmol/m2/s) negatively regulated the accumulation of β-carotene; positively induced the accumulation of zeaxanthin, echinenone, and canthaxanthin; and continuously promoted accumulation of zeaxanthin and canthaxanthin in C. reinhardtii. Metabolomics analysis suggested that high light exposure stress promoted biosynthesis of carotenoids, improved the intermediates associated with the astaxanthin synthesis pathway, and promoted conversion of β-carotene to downstream substances. Several strategies were implemented to improve canthaxanthin production in C. reinhardtii to achieve overexpression of β-carotene ketolase genes from different sources, including strong promoters, insertion introns, and chloroplast conduction peptides. It was found that β-carotene, echinenone, and canthaxanthin were all significantly increased in the transformed C. reinhardtii overexpressing β-carotene ketolase. Among these, the highest canthaxanthin content was found in pH124-CrtO, which was seven times that observed in the wild type. Moreover, the metabolomics analysis of carotenoids showed promotion of the abscisic acid and astaxanthin pathways in the transformed C. reinhardtii.DiscussionThe results of this study provide a new scheme for manipulating the metabolism of carotenoids and promoting the synthesis of high-value carotenoids in C. reinhardtii

Intranasal Delivery of miR-146a Mimics Delayed Seizure Onset in the Lithium-Pilocarpine Mouse Model

Unveiling the key mechanism of temporal lobe epilepsy (TLE) for the development of novel treatments is of increasing interest, and anti-inflammatory miR-146a is now considered a promising molecular target for TLE. In the current study, a C57BL/6 TLE mouse model was established using the lithium-pilocarpine protocol. The seizure degree was evaluated according to the Racine scale, and level 5 was considered the threshold for generalized convulsions. Animals were sacrificed to analyze the hippocampus at three time points (2 h and 4 and 8 weeks after pilocarpine administration to evaluate the acute, latent, and chronic phases, resp.). After intranasal delivery of miR-146a mimics (30 min before pilocarpine injection), the percent of animals with no induced seizures increased by 6.7%, the latency to generalized convulsions was extended, and seizure severity was reduced. Additionally, hippocampal damage was alleviated. While the relative miR-146a levels significantly increased, the expression of its target mRNAs (IRAK-1 and TRAF-6) and typical inflammatory modulators (NF-κB, TNF-α, IL-1β, and IL-6) decreased, supporting an anti-inflammatory role of miR-146a via the TLR pathway. This study is the first to demonstrate that intranasal delivery of miR-146a mimics can improve seizure onset and hippocampal damage in the acute phase of lithium-pilocarpine-induced seizures, which provides inflammation-based clues for the development of novel TLE treatments

Atomically thin photoanode of InSe/graphene heterostructure

很多物理和化学过程都发生在固体电极与溶液的表界面处，因而表面处离子的吸附、聚集及其在表面的反应都对整个反应过程起到至关重要的作用。然而使用传统的固体电极通常表现出的是体相和表面的复合性质，使得单纯研究电极材料表面效应及表面离子的动力学还存在挑战。二维材料由于其具有单原子层的厚度，晶体中所有原子都处在表面，因而可以作为一种理想的模型体系来仅针对此类表面现象进行研究。课题组选择光电化学池（PEC）分解水反应中的决速步骤氧析出半反应（OER）以作为研究表面离子行为的探针反应。光电极选择同时具有高迁移率、匹配的能级结构以及被抑制的光生电子-空穴复合的单层的二维硒化铟（InSe）材料。并且在手套箱提供的惰性气氛中用单层石墨烯对InSe进行封装，保证了光电极测试条件下长时间的稳定性。该工作揭示了二维异质结表面性质与反应活性的内在联系，希望能为研究电极表面离子效应提供新的材料平台。后续通过选择具有合适表面性能的二维材料，并与传统光电极材料结合，有望发展新型的高性能光阳极材料。 这一研究工作的实验部分是在化学化工学院曹阳教授指导下完成，博士生郑海红、鲁艺珍与广东工业大学轻工化工学院叶凯航博士为论文的共同第一作者。理论计算部分在程俊教授的指导下，由博士生胡晋媛完成。Achieving high-efficiency photoelectrochemical water splitting requires a better understanding of ion kinetics, e.g., diffusion, adsorption and reactions, near the photoelectrode's surface. However, with macroscopic three-dimensional electrodes, it is often difficult to disentangle the contributions of surface effects to the total photocurrent from that of various factors in the bulk. Here, we report a photoanode made from a InSe crystal monolayer that is encapsulated with monolayer graphene to ensure high stability. We choose InSe among other photoresponsive two-dimensional (2D) materials because of its unique properties of high mobility and strongly suppressing electron–hole pair recombination. Using the atomically thin electrodes, we obtained a photocurrent with a density >10 mA cm−2 at 1.23 V versus reversible hydrogen electrode, which is several orders of magnitude greater than other 2D photoelectrodes. In addition to the outstanding characteristics of InSe, we attribute the enhanced photocurrent to the strong coupling between the hydroxide ions and photogenerated holes near the anode surface. As a result, a persistent current even after illumination ceased was also observed due to the presence of ions trapped holes with suppressed electron-hole recombination. Our results provide atomically thin materials as a platform for investigating ion kinetics at the electrode surface and shed light on developing nextgeneration photoelectrodes with high efficiency.The experimental work was supported by the National Key R&D Program of China (2018YFA0306900 and 2018YFA0209500), the National Natural Science Foundation of China (21872114), and China Postdoctoral Science Foundation (2020M682616). 该工作得到了国家重点研究计划（2018YFA0306900、2018YFA0209500），国家自然科学基金（21872114）、中国博士后科学基金（2020M682616）的支持

The Genomes of Oryza sativa: A History of Duplications

We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000–40,000. Only 2%–3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family