Human exposure to environmental chemicals is most correctly characterized as exposure to mixtures of these agents. The metals/metalloids, lead (Pb), cadmium (Cd), and arsenic (As), are among the ...leading toxic agents detected in the environment. Exposure to these elements, particularly at chronic low dose levels, is still a major public health concern. Concurrent exposure to Pb, Cd, or As may produce additive or synergistic interactions or even new effects that are not seen in single component exposures. Evaluating these interactions on a mechanistic basis is essential for risk assessment and management of metal/metalloid mixtures. This paper will review a number of individual studies that addressed interactions of these metals/metalloids in both experimental and human exposure studies with particular emphasis on biomarkers. In general, co-exposure to metal/metalloid mixtures produced more severe effects at both relatively high dose and low dose levels in a biomarker-specific manner. These effects were found to be mediated by dose, duration of exposure and genetic factors. While traditional endpoints, such as morphological changes and biochemical parameters for target organ toxicity, were effective measures for evaluating the toxicity of high dose metal/metalloid mixtures, biomarkers for oxidative stress, altered heme biosynthesis parameters, and stress proteins showed clear responses in evaluating toxicity of low dose metal/metalloid mixtures. Metallothionein, heat shock proteins, and glutathione are involved in regulating interactive effects of metal/metalloid mixtures at low dose levels. These findings suggest that further studies on interactions of these metal/metalloid mixtures utilizing biomarker endpoints are highly warranted.
Wind power is growing rapidly as a green and clean energy source. As the core part of a wind turbine, the blades are subjected to enormous stress in harsh environments over a long period of time and ...are therefore extremely susceptible to damage, while at the same time, they are costly, so it is important to monitor their damage in a timely manner. This paper is based on the detection of blade damage using acoustic emission signals, which can detect early minor damage and internal damage to the blades. Instead of conventional piezoelectric sensors, we use fiber optic gratings as sensing units, which have the advantage of small size and corrosion resistance. Furthermore, the sensitivity of the system is doubled by replacing the conventional FBG (fiber Bragg grating) with a π-phase-shifted FBG. For the noise problem existing in the system, this paper combines the traditional WPD (wavelet packet decomposition) denoising method with EMD (empirical mode decomposition) to achieve a better noise reduction effect. Finally, small wind turbine blades are used in the experiment and their acoustic emission signals with different damage are collected for feature analysis, which sets the stage for the subsequent detection of different damage degrees and types.
Detecting rumors on social media has become increasingly necessary due to their rapid spread and adverse impact on society. Currently, most rumor detection methods fail to consider the ...non-consecutive semantic features of the post's text or the authority of commenting users. Therefore, we propose a novel rumor detection method that integrates non-consecutive semantic features and stances considering user weights. Firstly, we employ a pre-trained stance detection model to extract stance information for each comment for the post and then determine the weight of the stance information based on commenting user characteristics. Secondly, we input the time-series data of stance information and the corresponding comment user sequence data into the Cross-modal Transformer to learn the temporal features of comment stances. We then use pointwise mutual information to transform the discretized and fragmented post's text into a weighted graph and utilize a graph attention network that considers edge weights to process the graph and learn the non-consecutive semantic features of the text. Finally, we concatenate the temporal features of comment stances with the non-consecutive semantic features of the post's text and input them into a multi-layer perceptron for rumor classification. Experimental results on two public social media rumor datasets, Weibo and PHEME, demonstrate that our method outperforms the baselines. Our method is at least 12 hours ahead of the baseline methods for early rumor detection.
How to discover hotspot in the Internet public opinions effectively is a hot research field for the researchers related which plays a key role for governments and corporations to find useful ...information from mass data in the Internet. An improved K-means algorithm for hotspot discovery in internet public opinions is presented based on the analysis of existing defects and calculation principle of original K-means algorithm. First, some new methods are designed to preprocess website texts, select and express the characteristics of website texts, and define the similarity between two website texts, respectively. Second, clustering principle and the method of initial classification centers selection are analyzed and improved in order to overcome the limitations of original K-means algorithm. Finally, the experimental results verify that the improved algorithm can improve the clustering stability and classification accuracy of hotspot discovery in internet public opinions when used in practice.
Abstract
Amongst the rare-earth perovskite nickelates, LaNiO
3
(LNO) is an exception. While the former have insulating and antiferromagnetic ground states, LNO remains metallic and non-magnetic down ...to the lowest temperatures. It is believed that LNO is a strange metal, on the verge of an antiferromagnetic instability. Our work suggests that LNO is a quantum critical metal, close to an antiferromagnetic quantum critical point (QCP). The QCP behavior in LNO is manifested in epitaxial thin films with unprecedented high purities. We find that the temperature and magnetic field dependences of the resistivity of LNO at low temperatures are consistent with scatterings of charge carriers from weak disorder and quantum fluctuations of an antiferromagnetic nature. Furthermore, we find that the introduction of a small concentration of magnetic impurities qualitatively changes the magnetotransport properties of LNO, resembling that found in some heavy-fermion Kondo lattice systems in the vicinity of an antiferromagnetic QCP.
Exposure to chemical mixtures is a common and important determinant of toxicity and is of particular concern due to their appearance in sources of drinking water. Despite this, few
in vivo mixture ...studies have been conducted to date to understand the health impact of chemical mixtures compared to single chemicals. Interactive effects of lead (Pb), cadmium (Cd) and arsenic (As) were evaluated in 30-, 90-, and 180-day factorial design drinking water studies in rats designed to test the hypothesis that ingestion of such mixtures at individual component Lowest-Observed-Effect-Levels (LOELs) results in increased levels of the pro-oxidant delta aminolevulinic acid (ALA), iron, and copper. LOEL levels of Pb, Cd, and As mixtures resulted in the increased presence of mediators of oxidative stress such as ALA, copper, and iron. ALA increases were followed by statistically significant increases in kidney copper in the 90- and 180-day studies. Statistical evidence of interaction was identified for six biologically relevant variables: blood delta aminolevulinic acid dehydratase (ALAD), kidney ALAD, urinary ALA, urinary iron, kidney iron, and kidney copper. The current investigations underscore the importance of considering interactive effects that common toxic agents such as Pb, Cd, and As may have upon one another at low-dose levels. The interactions between known toxic trace elements at biologically relevant concentrations shown here demonstrate a clear need to rigorously review methods by which national/international agencies assess health risks of chemicals, since exposures may commonly occur as complex mixtures.
► Effects of cyclophosphamide in stem spermatogonia. ► Recovery of spermatogenesis evaluated
in situ and after transplantation. ► Stem cells showed good recovery
in situ. ► Poor recovery after ...transplantation. ► Cyclophosphamide caused stem cell depletion and functional damage.
Spermatogenesis is sensitive to the chemotherapeutic drug cyclophosphamide, which decreases the patients’ sperm count. Since the recovery of fertility is dependent on regeneration from stem cells, in the present study we evaluated the ability of cyclophosphamide-exposed stem spermatogonia from mice to regenerate spermatogenesis
in situ and after transplantation. When seven doses of cyclophosphamide were given at 4-day intervals, the differentiating germ cells were largely eliminated but ∼50% of the undifferentiated type A spermatogonia remained. We monitored the recovery and found that sperm production recovered to 64% of control within the time expected. When the cyclophosphamide-surviving spermatogonia were transplanted into recipient mice, recovery of spermatogenesis from the cyclophosphamide-exposed donor cells was observed, but was reduced when compared to cells from cryptorchid donors. Thus, multidose regimens of cyclophosphamide did not eliminate the stem spermatogonia, but resulted in cell loss and residual damage.
Objective
This study aims to explore the effect of new-style anterior and posterior vaginal wall repair combined with modified ischial spine fascia fixation on patients with pelvic organ prolapse ...(POP) and their postoperative quality of life.
Methods
A total of 88 patients with POP and elective surgery admitted to Anqing Hospital affiliated to Anhui Medical University from March 2018 to March 2021 were retrospectively analyzed. According to their surgical methods, patients were divided into an observation group 44 cases, all underwent new-style anterior and posterior vaginal wall repair combined with modified ischial spine fascia fixation (new-style APVR-modified ISFF) and a control group 44 cases, all underwent traditional anterior and posterior vaginal wall repair combined with sacrospinous ligament fixation (traditional APVR- SLF). The perioperative indicators were compared between the two groups. The pelvic floor function, pelvic organ prolapse quantification (POP-Q) classification, and quality of life were observed before operation, 3 months after operation, and 6 months after operation. All patients were followed-up.
Results
Compared with the control group, the observation group had more advantages in intraoperative blood loss, operation time, urinary catheter indwelling time, postoperative anal exhaust time, and hospitalization time (
P
< 0.05). In terms of pelvic floor function, patients of both groups showed significant improvement at 3 months and 6 months after surgery (
P
< 0.05). In terms of quality of life, the two groups exhibited significant improvement at 6 months after surgery (
P
< 0.05). PFIQ-7, PFDI-20, and UDI-6P of the observational group were lower than those of the control group, while PISQ-12 was higher than that of the control group but all with no significant difference (
P
> 0.005). In addition, the total complication rate of the observation group was 2.27% (1/44), which was significantly lower than 22.73% (10/44) of the control group (
P
< 0.05).
Conclusion
New-style APVR-modified ISFF can effectively treat POP and improve the quality of life of such patients, with less postoperative complications and high safety.
This study focused on large-scale roof-fall accidents occurred in large-section coal seam roadways of Bayangaole Coal Mine, Inner Mongolia, China, and investigated the occurrence mechanism of ...roof-fall and the related supporting control method in detail. Firstly, the fracture characteristics of the surrounding rocks on the roadway roof were measured using a stratum detector. The results showed that the roadway roof underwent the most severe failure with a maximum deformation of 3.53 m; the bedding separation and fracture zones were distributed at irregular intervals. Accordingly, the entire stratum was separated into several thin sublayers, significantly reducing the stability of roof. In addition, the roof medium grained sandstone of roadway is water-rich strata, and water aggravates the damage of roof. Next, the mechanism of the occurrence of roof-fall accidents in the roadway was elucidated in detail. The following three reasons are mainly attributed to the occurrence of roof-fall accidents: (i) effects of mining-induced stress and tectonic stress, (ii) existence of equipment cavern on the side of roadway, and (iii) unreasonable support parameters. On that basis, a new supporting design is proposed, including a more reasonable arrangement of anchor cables and bolts, bolts with full-length anchorage which are applicable in cracked and water-rich roadway, high-strength anchor cables, and crisscrossed steel bands. Moreover, high pretightening force was applied. Finally, a field test was performed, and the mining-induced roof displacement and stress on anchor cable (bolt) were monitored in the test section. The maximum roof displacements at the two monitoring sections were 143 mm and 204 mm, respectively, far smaller than the roadway’s allowable deformation. Moreover, the stress on roof anchor cables (bolts) was normal, and no anchorage-dragging and tensile failure phenomena were observed. The monitoring data indicated that the new supporting design was remarkable on the control of large-section coal seam roadway roof deformation.
Recombinant adeno-associated virus (rAAV) vectors offer promise for gene therapy of alpha-1 antitrypsin (AAT) deficiency. A toxicology study in mice evaluated intramuscular injection of an rAAV ...vector expressing human AAT (rAAV-CB-hAAT) produced using a herpes simplex virus (HSV) complementation system or a plasmid transfection (TFX) method at doses of 3 × 10(11) vg (1.2 × 10(13) vg/kg) for both vectors and 2 × 10(12) vg (8 × 10(13) vg/kg) for the HSV-produced vector. The HSV-produced vector had favorable in vitro characteristics in terms of purity, efficiency of transduction, and hAAT expression. There were no significant differences in clinical findings or hematology and clinical chemistry values between test article and control groups and no gross pathology findings. Histopathological examination demonstrated minimal to mild changes in skeletal muscle at the injection site, consisting of focal chronic interstitial inflammation and muscle degeneration, regeneration, and vacuolization, in vector-injected animals. At the 3 × 10(11) vg dose, serum hAAT levels were higher with the HSV-produced vector than with the TFX-produced vector. With the higher dose of HSV-produced vector, the increase in serum hAAT levels was dose-proportional in females and greater than dose-proportional in males. Vector copy numbers in blood were highest 24 hr after dosing and declined thereafter, with no detectable copies present 90 days after dosing. Antibodies to hAAT were detected in almost all vector-treated animals, and antibodies to HSV were detected in most animals that received the highest vector dose. These results support continued development of rAAV-CB-hAAT for treatment of AAT deficiency.
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