Effects of microplastics on soil microorganisms and microbial functions in nutrients and carbon cycling - A review.

The harmful effects of microplastics (MPs) pollution in the soil ecosystem have drawn global attention in recent years. This paper critically reviews the effects of MPs on soil microbial diversity and functions in relation to nutrients and carbon cycling. Reports suggested that both plastisphere (MP-microbe consortium) and MP-contaminated soils had distinct and lower microbial diversity than that of non-contaminated soils. Alteration in soil physicochemical properties and microbial interactions within the plastisphere facilitated the enrichment of plastic-degrading microorganisms, including those involved in carbon (C) and nutrient cycling. MPs conferred a significant increase in the relative abundance of soil nitrogen (N)-fixing and phosphorus (P)-solubilizing bacteria, while decreased the abundance of soil nitrifiers and ammonia oxidisers. Depending on soil types, MPs increased bioavailable N and P contents and nitrous oxide emission in some instances. Furthermore, MPs regulated soil microbial functional activities owing to the combined toxicity of organic and inorganic contaminants derived from MPs and contaminants frequently encountered in the soil environment. However, a thorough understanding of the interactions among soil microorganisms, MPs and other contaminants still needs to develop. Since currently available reports are mostly based on short-term laboratory experiments, field investigations are needed to assess the long-term impact of MPs (at environmentally relevant concentration) on soil microorganisms and their functions under different soil types and agro-climatic conditions.

Fat body-specific reduction of CTPS alleviates HFD-induced obesity.

Obesity induced by high-fat diet (HFD) is a multi-factorial disease including genetic, physiological, behavioral, and environmental components. Drosophila has emerged as an effective metabolic disease model. Cytidine 5'-triphosphate synthase (CTPS) is an important enzyme for the de novo synthesis of CTP, governing the cellular level of CTP and the rate of phospholipid synthesis. CTPS is known to form filamentous structures called cytoophidia, which are found in bacteria, archaea, and eukaryotes. Our study demonstrates that CTPS is crucial in regulating body weight and starvation resistance in Drosophila by functioning in the fat body. HFD-induced obesity leads to increased transcription of CTPS and elongates cytoophidia in larval adipocytes. Depleting CTPS in the fat body prevented HFD-induced obesity, including body weight gain, adipocyte expansion, and lipid accumulation, by inhibiting the PI3K-Akt-SREBP axis. Furthermore, a dominant-negative form of CTPS also prevented adipocyte expansion and downregulated lipogenic genes. These findings not only establish a functional link between CTPS and lipid homeostasis but also highlight the potential role of CTPS manipulation in the treatment of HFD-induced obesity.

The high rate of obesity has created a global health burden by leading to increased rates of chronic diseases like diabetes and cardiovascular disease. Tackling this issue is complicated as it is influenced by many factors, including genetics, behaviour and environment. To better understand the biochemical changes that underly metabolic issues in a simpler setting, scientists can study fruit flies in the laboratory. These insects share many genes with humans and have similar responses to a high-fat diet. Previous research identified an enzyme, called CTP synthase (CTPS), which is produced in large amounts by the liver and fat tissue in mammals, and the equivalent in fruit flies, known as the fat body. Multiple CTPS molecules can combine to form long strands of protein called cytoophidia, which have been seen in organisms ranging from humans to bacteria. Recent results showed that the fruit fly equivalent of CTPS drives fat cells to stick together, which is necessary to maintain and form fat tissue. However, it is not clear if altering the levels of CTPS can affect the response to a high-fat diet. To address this, Liu, Zhang, Wang et al. studied fruit flies on a high-fat diet, showing that this increased the production of CTPS. When the flies were treated to deplete levels of CTPS in the fat body, they had less body weight gain, smaller fat cells and lower amounts of fats in the body. Genetically modified flies with a version of CTPS that was unable to form cytoophidia also showed fewer signs of obesity, indicating how the enzyme might influence the response to dietary fats. These findings further implicate CTPS in the cause of obesity and help to understand its role. However, it remains to be seen if this also applies to humans. If this is the case, drugs that block the activity of CTPS could help to reduce the impact of a high-fat diet on public health.

ROS-responsive exogenous functional mitochondria can rescue neural cells post-ischemic stroke.

Background: The transfer of mitochondria from healthy mesenchymal stem cells (MSCs) to injured MSCs has been shown to have potential therapeutic benefits for neural cell post-ischemic stroke. Specifically, functional mitochondria can perform their normal functions after being internalized by stressed cells, leading to host cell survival. However, while this approach shows promise, there is still a lack of understanding regarding which neural cells can internalize functional mitochondria and the regulatory mechanisms involved. To address this gap, we investigated the ability of different neural cells to internalize exogenous functional mitochondria extracted from MSCs. Methods: Functional mitochondria (F-Mito) isolated from umbilical cord derived-MSCs (UCMSCs) were labeled with lentivirus of HBLV-mito-dsred-Null-PURO vector. The ability of stressed cells to internalize F-Mito was analyzed using a mouse (C57BL/6 J) middle cerebral artery occlusion (MCAO) model and an oxygen-glucose deprivation/reoxygenation (OGD/R) cell model. The cell viability was measured by CCK-8 kit. Time-course of intracellular ROS levels in stressed cells were analyzed by DCFH-DA staining after OGD/R and F-Mito treatment. MitoSOX, Mitotracker and WGA labeling were used to assess the relationship between ROS levels and the uptake of F-Mito at the single-cell level. Pharmacological modulation of ROS was performed using acetylcysteine (ROS inhibitor). Results: Our findings demonstrate that neurons and endothelial cells are more effective at internalizing mitochondria than astrocytes, both in vitro and in vivo, using an ischemia-reperfusion model. Additionally, internalized F-Mito decreases host cell reactive oxygen species (ROS) levels and rescues survival. Importantly, we found that the ROS response in stressed cells after ischemia is a crucial determinant in positively mediating the internalization of F-Mito by host cells, and inhibiting the generation of ROS chemicals in host cells may decrease the internalization of F-Mito. These results offer insight into how exogenous mitochondria rescue neural cells via ROS response in an ischemic stroke model. Overall, our study provides solid evidence for the translational application of MSC-derived mitochondria as a promising treatment for ischemic stroke.

Detection of emerging HoBi-like Pestivirus (BVD-3) during an epidemiological investigation of bovine viral diarrhea virus in Xinjiang: a first-of-its-kind report.

Xinjiang pastoral area is the second largest pastoral area in China, accounting for 26.8% of the available grassland area in the country, and the geographical advantage of cattle breeding industry is very obvious. Bovine viral diarrhea virus (BVDV) has always been one of the important viral diseases that have plagued the development of cattle farming industry in the world. As one of the main pastoral areas of China's cattle farming industry, the Xinjiang pastoral area has also been deeply affected. In this study, 6,153 bovine serum samples were collected from 18 large-scale cattle farms in 13 cities in Xinjiang. The antibodies and antigens of 6,153 and 588 serum samples were detected by serological detection methods, respectively. Ten serum samples, which were antigen-positive by ELISA, were randomly selected for RT-PCR detection, sequencing, and phylogenetic analysis of suspected HoBi-like Pestivirus (HoBiPeV) strains. The results showed that the positive rates of BVDV antibodies and antigens were 53.68% (3,303/6,153) and 6.12% (36/588), respectively. One of the 10 randomly selected seropositive samples was infected with the HoBiPeV strain. HoBiPeV, also referred to as BVDV-3, is an emerging atypical Pestivirus that occurs in cattle and small ruminants, and its clinical signs are similar to those of BVDV infection. Based on the whole genome of the BVDV-3 reference strain (JS12/01) on the GenBank, the homology of the detected strain was 96.02%. The whole genome nucleotide sequence was submitted to the GenBank database, and the gene accession number was obtained: OP210314. The whole genome of isolate OP210314 was 12.239 nucleotides and contained a 5'-UTR of 340 nucleotides, a 3'-UTR of 199 nucleotides, and a large open reading frame (ORF) encoding a polyprotein consisting of 3,899 amino acids. In conclusion, the prevalence rate of BVDV infection in Xinjiang dairy cows is high, and the genetic diversity is increasing. This study successfully identified and isolated HoBiPeV in Xinjiang for the first time, posing a potential threat to the cattle industry in Xinjiang.

In vitro digestion and fermentation combined with microbiomics and metabolomics reveal the mechanism of superfine yak bone powder regulating lipid metabolism by altering human gut microbiota.

The effects of superfine yak bone powder (YBP) on human gut microbiota (HGM) were investigated by in vitro digestion and fermentation combined with microbiomics and metabolomics. Results showed that size reduction and protein structural degradation during digestion allowed superfine YBP to release more Ca2+ than CaCO3 powders with similar particle size. Moreover, the indigestible YBP further influenced HGM and was associated with increased occurrence of beneficial bacteria such as Megasphaera spp., Megamonas spp., Acidaminococcus spp., and Prevotella spp. The altered HGM was associated with greater production of short-chain fatty acids with 4-6 carbon atoms. Furthermore, the indigestible YBP was associated with up-regulation of many lipid-related metabolites, including taurine, secondary bile acids, saturated long-chain fatty acids, and ω-3/ω-6 polyunsaturated fatty acids, which modulated favorably lipid metabolic pathways. These findings implied the potential activity of superfine YBP as a food fortifier in favorably altering HGM community structure and regulating lipid metabolism.

LOC554202 contributes to chordoma progression by sponging miR-377-3p and up-regulating SMAD3.

Chordoma is a rare malignant bone tumor originating from the remnants of the notochord. Here, the role of long noncoding LOC554202 in chordoma progression and its associated mechanism were explored. Cell proliferation was analyzed by 3-(4, 5-dimethylthiazol-2-yl)-2, 5 diphenyltetrazolium bromide and colony formation assays. Flow cytometry was conducted to analyze cell apoptosis rate. The migration and invasion of chordoma cells were analyzed by transwell migration and invasion assays and wound healing assays. A xenograft tumor model was established in nude mice to explore the role of LOC554202 in regulating tumor growth in vivo . The interaction between microRNA-377-3p (miR-377-3p) and LOC554202 or sekelsky mothers against d PP (SMAD) family member 3 (SMAD3) was verified by dual-luciferase reporter and RNA immunoprecipitation assays. The glycolytic rate of chordoma cells was analyzed using glucose assay kit, lactic acid kit and ApoSENSOR ADP/ATP ratio assay kit. LOC554202 expression was upregulated in chordoma tissues and cell lines. LOC554202 silencing suppressed the proliferation, migration and invasion and induced the apoptosis of chordoma cells. LOC554202 knockdown restrained xenograft tumor growth in vivo . miR-377-3p was confirmed as a target of LOC554202, and miR-377-3p silencing largely overturned LOC554202 knockdown-mediated anti-tumor effects in chordoma cells. miR-377-3p interacted with the 3' untranslated region (3'UTR) of SMAD3 and miR-377-3p overexpression-mediated antitumor effects in chordoma cells were largely attenuated by SMAD3 overexpression. LOC554202 could positively regulate SMAD3 expression by sponging miR-377-3p in chordoma cells. LOC554202 contributed to the glycolysis of chordoma cells by targeting binding to miR-377-3p/SMAD3 axis. LOC554202 facilitated the proliferation, migration, invasion and glycolysis and inhibited the apoptosis of chordoma cells by mediating miR-377-3p/SMAD3 axis.

Second-Level Microgroove Convexity is Critical for Air Plastron Restoration on Immersed Hierarchical Superhydrophobic Surfaces.

Air plastrons trapped on the surfaces of underwater superhydrophobic surfaces are critical for their function. Fibrillar morphologies offer a natural pathway, yet they are limited to a narrow range of liquid-surface systems and are vulnerable to pressure fluctuations that irreversibly destroy the air layer plastron. Inspired by the convexly grooved bases of water fern (Salvinia) leaves that support their fibrous outgrowths, we focus on the effect of such second-level grooved structures or microgrooves on the plastron restoration on immersed three-dimensional (3D)-printed hierarchical surfaces. Elliptical, interconnected microgrooves are fabricated with varying surface curvatures to study the effect of their morphology. Immersion experiments reveal that the convex groove curvature stabilizes a seed gas layer (SGL) that facilitates plastron restoration for all immersed hydrophobic surfaces. Theoretical calculations and atomic-scale computations reveal that the SGL storage capacity that sets the SGL robustness follows from the liquid menisci adaption to the groove geometry and pressure, from micro- to nanoscales, and it can be further tuned using separated grooves. Our study highlights groove convexity as a key morphological feature for the design of second-level architectures for underwater air plastron restoration on hierarchical superhydrophobic surfaces.

Simultaneous measurement of near-water-film air temperature and humidity fields based on dual-wavelength digital holographic interferometry.

We present a method to reconstruct the near-water-film air temperature and humidity distributions synchronously by measuring the phase delays based on dual-wavelength digital holographic interferometry. A falling water film device was used to create a water film evaporation environment and generate axially uniform temperature and humidity fields. The relationship between air temperature, humidity and phase delay is derived from the Edlen equations. With such relationship, the temperature and humidity distributions can be solved directly according to phase delays of two different wavelengths. An edge phase enhancement method and an error elimination method with PSO are presented to improve the measurement accuracy. The temperature and humidity fields in the falling water film model were experimentally reconstructed with temperature deviation of 0.06% and relative humidity deviation of 2.61%.

Expression of mosquito miRNAs in entomopathogenic fungus induces pathogen-mediated host RNA interference and increases fungal efficacy.

The growing threat of insecticide resistance prompts the urgent need to develop additional tools for mosquito control. Entomopathogenic fungi provide an eco-friendly alternative to chemical insecticides. One limitation to the use of mycoinsecticides is their relatively low virulence. Here, we report an approach for suppressing mosquito immunity and increasing fungal virulence. We engineered Beauveria bassiana to express Aedes immunosuppressive microRNAs (miRNAs) to induce host RNA interference (RNAi) immune responses. We show that engineered strains can produce and deliver the miRNAs into host cells to activate cross-kingdom RNAi during infection and suppress mosquito immunity by targeting multiple host genes, thereby dramatically increasing fungal virulence against Aedes aegypti and Galleria mellonella larvae. Importantly, expressing host miRNAs also significantly increases fungal virulence against insecticide-resistant mosquitoes, creating potential for insecticide-resistance management. This pathogen-mediated RNAi (pmRNAi)-based approach provides an innovative strategy to enhance the efficacy of fungal insecticides and eliminate the likelihood of resistance development.

Cytoophidia coupling adipose architecture and metabolism.

Tissue architecture determines its unique physiology and function. How these properties are intertwined has remained unclear. Here we show that the metabolic enzyme CTP synthase (CTPS) form filamentous structures termed cytoophidia along the adipocyte cortex in Drosophila adipose tissue. Loss of cytoophidia, whether due to reduced CTPS expression or a point mutation that specifically abrogates its polymerization ability, causes impaired adipocyte adhesion and defective adipose tissue architecture. Moreover, CTPS influences integrin distribution and dot-like deposition of type IV collagen (Col IV). Col IV-integrin signaling reciprocally regulates the assembly of cytoophidia in adipocytes. Our results demonstrate that a positive feedback signaling loop containing both cytoophidia and integrin adhesion complex couple tissue architecture and metabolism in Drosophila adipose tissue.

Analysis of the Curative Effect and Prognostic Factors of Anterior Cervical Surgery for Spinal Cord Injury without Radiographic Abnormalities.

Objective: The study aimed to investigate the effect of anterior cervical surgery in the treatment of spinal cord injury without radiographic abnormalities (SCIWORAs) and analyze the related factors affecting the prognosis of patients. Methods: A total of 86 patients with SCIWORA who were admitted to our hospital from June 2018 to March 2021 were selected as the research subjects. According to the different treatment methods selected by the patients, they were divided into the control group (n = 38) and the observation group (n = 48). The control group was treated with conservative therapy, and the observation group was treated with anterior cervical total laminectomy decompression, internal fixation, and bone graft fusion. The efficacy of the treatment was assessed preoperatively and 6 months after surgery using the Japanese Orthopedics Association (JOA) functional evaluation criteria for cervical spinal cord injury. The improvement rate of the JOA score at the last follow-up visit was calculated according to the Hirabayashi formula to evaluate the prognosis of patients. Results: The JOA score of the observation group six months after surgery was (14.98 ± 2.75) that was higher than that of the control group (12.16 ± 2.54) (P < 0.05). After surgery, the improvement rate of the JOA score in the observation group was higher than that in the control group (P < 0.05). After surgery, the scores of health condition, physiological function, and role physical in the observation group were (23.18 ± 1.09), (22.75 ± 1.54), and (22.64 ± 1.46), which were higher than those in the control groups (20.94 ± 1.65), (20.26 ± 1.78), and (19.56 ± 1.82) (P < 0.05). The results of univariate analysis showed that the ASIA classification of cervical spinal cord injury, the type of MRI cervical spinal cord injury, the scope of cervical spinal cord injury, lumbar disc herniation, and the time from injury to treatment were all related to the prognosis of the patients (P < 0.05). Multivariate analysis showed that the ASIA classification of cervical spinal cord injury, the type of MRI cervical spinal cord injury, the scope of cervical spinal cord injury, and the time from injury to treatment were the independent factors affecting the prognosis of patients (P < 0.05). Conclusion: For patients with SCIWORA, anterior total lamina decompression and internal fixation with bone grafting and fusion can effectively promote the recovery of cervical spinal cord function and improve the prognosis and quality of life of patients. The ASIA classification of cervical spinal cord injury, the type of MRI cervical spinal cord injury, the scope of cervical spinal cord injury, and the time from injury to treatment were the independent prognostic factors for patients.

Numerical Analysis and Comparison of Four Stabilized Finite Element Methods for the Steady Micropolar Equations.

In this paper, four stabilized methods based on the lowest equal-order finite element pair for the steady micropolar Navier-Stokes equations (MNSE) are presented, which are penalty, regular, multiscale enrichment, and local Gauss integration methods. A priori properties, existence, uniqueness, stability, and error estimation based on Fem approximation of all the methods are proven for the physical variables. Finally, some numerical examples are displayed to show the numerical characteristics of these methods.

Connecting Ras and CTP synthase in Drosophila.

CTP synthase (CTPS), the enzyme responsible for the last step of de novo synthesis of CTP, forms filamentous structures termed cytoophidia in all three domains of life. Here we report that oncogenic Ras regulates cytoophidium formation in Drosophila intestines. Overexpressing active Ras induces elongate and abundant cytoophidia in intestinal stem cells (ISCs) and enteroblasts (EBs). Knocking-down CTPS in ISCs/EBs suppresses the over- proliferation phenotype induced by ectopic expression of active Ras. Moreover, disrupting cytoophidium formation increases the number of proliferating cells in the background of overexpressing active Ras. Therefore, our results demonstrate a link between Ras and CTPS.

circ_0067934 promotes the progression of papillary thyroid carcinoma cells through miR-1301-3p/HMGB1 axis.

Papillary thyroid carcinoma (PTC) is the most prevalent form of thyroid cancer (TC). There is increasing evidence that circular RNAs play a role in the tumorigenesis of PTC. The aim of our study was to evaluate the potential function of circ_0067934 in PTC and the underlying molecular mechanism. In our study, cell viability assay, quantitative real-time PCR (qRT-PCR), colony formation assay, flow cytometry, wound-healing assay, Transwell invasion assay, western blot, soft agar assay, RNA immunoprecipitation (RIP), dual-luciferase reporter assay, immunohistochemical (IHC) staining, and tumor xenograft formation were conducted to evaluate the effects of circ_0067934 in PTC cells. We found that circ_0067934 was upregulated in PTC tissues and cell lines. Knockdown of circ_0067934 inhibited growth, colony formation, migration, invasion, EMT, and tumor xenograft growth, and induced apoptosis of PTC cells. Moreover, circ_0067934 acted as a molecular sponge for miR-1301-3p, and depletion of miR-1301-3p abrogated the effects of circ_0067934 knockdown in PTC cells. In addition, HMGB1 was a target of miR-1301-3p, and miR-1301-3p overexpression inhibited the malignant effects of PTC cells via suppressing HMGB1. Furthermore, knockdown of circ_0067934 suppressed HMGB1 expression, PI3K/Akt, and MAPK activation by sponging miR-1301-3p. In nude mice, circ_0067934 depletion repressed tumor xenograft growth of PTC cells. In conclusion, our results provided a novel insight into circ_0067934 in the tumorigenesis and progression of PTC. circ_0067934 might be a prognostic marker or therapeutic target for PTC treatment.

Analysis of the Distribution of Urine Color and Its Relationship With Urine Dry Chemical Parameters Among College Students in Beijing, China - A Cross-Sectional Study.

Objectives: The objective of this study was to provide a new classification method by analyzing the relationship between urine color (Ucol) distribution and urine dry chemical parameters based on image digital processing. Furthermore, this study aimed to assess the reliability of Ucol to evaluate the states of body hydration and health. Methods: A cross-sectional study among 525 college students, aged 17-23 years old, of which 59 were men and 466 were women, was conducted. Urine samples were obtained during physical examinations and 524 of them were considered valid, including 87 normal samples and 437 abnormal dry chemistry parameters samples. The urinalysis included both micro- and macro-levels, in which the CIE L*a*b* values and routine urine chemical examination were performed through digital imaging colorimetry and a urine chemical analyzer, respectively. Results: The results showed that L* (53.49 vs. 56.69) in the abnormal urine dry chemistry group was lower than the normal group, while b* (37.39 vs. 33.80) was greater. Urine color can be initially classified based on shade by grouping b*. Abnormal urine dry chemical parameter samples were distributed more in the dark-colored group. Urine dry chemical parameters were closely related to Ucol. Urine specific gravity (USG), protein, urobilinogen, bilirubin, occult blood, ketone body, pH, and the number of abnormal dry chemical parameters were all correlated with Ucol CIE L*a*b*; according to a stepwise regression analysis, it was determined that more than 50% of the variation in the three-color space values came from the urine dry chemical parameters, and the b* value was most affected by USG (standardized coefficient ß = 0.734, p < 0.05). Based on a receiver operating characteristic curve (ROC) analysis, Ucol ≥ 4 provided moderate sensitivity and good specificity (AUC = 0.892) for the detection of USG ≥ 1.020. Conclusions: Our findings on the Ucol analysis showed that grouping Ucol based on b* value is an objective, simple, and practical method. At the same time, the results suggested that digital imaging colorimetry for Ucol quantification is a potential method for evaluating body hydration and, potentially, health.

Drosophila intestinal homeostasis requires CTP synthase.

CTP synthase (CTPS) senses all four nucleotides and forms filamentous structures termed cytoophidia in all three domains of life. How CTPS and cytoophidia function in a developmental context, however, remains underexplored. We report that CTPS forms cytoophidia in a subset of cells in the Drosophila midgut. We found that cytoophidia exist in intestinal stem cells (ISC) and enteroblasts in similar proportions. Both refeeding after starvation and feeding with dextran sulfate sodium (DSS) induce ISC proliferation and elongate cytoophidia. Knockdown of CTPS inhibits ISC proliferation. Remarkably, disruption of CTPS cytoophidia inhibits DSS-induced ISC proliferation. Taken together, these data suggest that both the expression level and the filament-form property of CTPS are crucial for intestinal homeostasis in Drosophila.

Fat body Ire1 regulates lipid homeostasis through the Xbp1s-FoxO axis in Drosophila.

The endoplasmic reticulum (ER)-resident transmembrane protein kinase/RNase Ire1 is a conserved sensor of the cellular unfolded protein response and has been implicated in lipid homeostasis, including lipid synthesis and transport, across species. Here we report a novel catabolic role of Ire1 in regulating lipid mobilization in Drosophila. We found that Ire1 is activated by nutrient deprivation, and, importantly, fat body-specific Ire1 deficiency leads to increased lipid mobilization and sensitizes flies to starvation, whereas fat body Ire1 overexpression results in the opposite phenotypes. Genetic interaction and biochemical analyses revealed that Ire1 regulates lipid mobilization by promoting Xbp1s-associated FoxO degradation and suppressing FoxO-dependent lipolytic programs. Our results demonstrate that Ire1 is a catabolic sensor and acts through the Xbp1s-FoxO axis to hamper the lipolytic response during chronic food deprivation. These findings offer new insights into the conserved Ire1 regulation of lipid homeostasis.

Silver nanoparticles in aquatic sediments: Occurrence, chemical transformations, toxicity, and analytical methods.

Sediments represent the major sink for released silver nanoparticles (AgNPs) in aquatic environments. It is well known that the environmental behavior and toxicity of AgNPs in sediments are governed by their specific chemical species instead of their total concentration. This review focuses on various chemical transformations of AgNPs in sediments, which have not been well outlined before. We first outline the concentrations of AgNPs in sediments. The predicted concentrations are 1-5 µg kg-1 in most model studies. Once enter sediments, AgNPs are transformed to different species (e.g., Ag2S, Ag-humic substance complexes, AgCl, and Ag+) during multiple chemical transformations, such as oxidative dissolution, sulfidation, chlorination, and complexation. Those chemical behaviors mitigate the toxicity of AgNPs by reducing their availability and decreasing Ag+ release. Benthic invertebrates and microbes are prone to be affected by AgNPs. AgNPs are found to be accumulated in sediment-dwelling organisms and transferred to higher trophic levels along the food web. Besides X-ray absorption spectroscopy, reliable separation procedures coupled with detection techniques, are powerful tools that characterize the speciation of AgNPs in sediments. More research is needed to investigate diverse chemical transformations in various sediments through development of novel techniques and mathematical models.

Real-Time HD Map Change Detection for Crowdsourcing Update Based on Mid-to-High-End Sensors.

Continuous maintenance and real-time update of high-definition (HD) maps is a big challenge. With the development of autonomous driving, more and more vehicles are equipped with a variety of advanced sensors and a powerful computing platform. Based on mid-to-high-end sensors including an industry camera, a high-end Global Navigation Satellite System (GNSS)/Inertial Measurement Unit (IMU), and an onboard computing platform, a real-time HD map change detection method for crowdsourcing update is proposed in this paper. First, a mature commercial integrated navigation product is directly used to achieve a self-positioning accuracy of 20 cm on average. Second, an improved network based on BiSeNet is utilized for real-time semantic segmentation. It achieves the result of 83.9% IOU (Intersection over Union) on Nvidia Pegasus at 31 FPS. Third, a visual Simultaneous Localization and Mapping (SLAM) associated with pixel type information is performed to obtain the semantic point cloud data of features such as lane dividers, road markings, and other static objects. Finally, the semantic point cloud data is vectorized after denoising and clustering, and the results are matched with a pre-constructed HD map to confirm map elements that have not changed and generate new elements when appearing. The experiment conducted in Beijing shows that the method proposed is effective for crowdsourcing update of HD maps.

A new numerical correction method for gamma spectra based on the system transformation theory of random signals.

The conventional correction techniques for gamma spectra usually use approximate algorithms, the calculation procedures are tedious and complicated, the obtained corrected spectra are usually the channel domain spectra even if they are calibrated by energy. Moreover, the spectra are still dependent upon system parameters themselves such as the gain of amplifier and the offset of ADC etc. In this paper, a new numerical correction method of gamma spectra was developed on the basis of the system transformation theory of random signals. By transforming the measured spectrum from the channel domain to the energy domain, the theoretical deposition energy spectrum which is energy domain spectrum, rather than channel domain spectrum can be obtained without any algorithm approximation processing. The presented method makes it possible to compare and exchange the gamma-ray spectrum data that are measured under different conditions or by different spectrometer systems equipped with the same type of detectors. To validate the method, a set of NaI (Tl) gamma spectra and three sets of HPGe gamma spectra were collected. The results show that serious spectral drifts and intensity variation in NaI (Tl) gamma spectra were effectively eliminated. The maximum relative drift of peak position, the maximum relative variation of peak height and that of FWHM before correction were 65.03%, 40.37% and 61.65%, respectively, and after correction, they became 0.19%, 2.81% and 0.85%, respectively, indicating that the method has strong ability to correct gamma spectra. HPGe gamma spectra were also well corrected using the presented method, and were identified as gamma radiation fingerprints of nuclear materials. The results show that the method can also improve the confidence degree of identifying nuclear materials significantly.