Search

Caffeine intake during pregnancy is common, while its effect on gut microbiota composition of offspring and the relationship with susceptibility to adult diseases remains unclear. This study aimed to confirm the effects of prenatal caffeine exposure (PCE) on the gut microbiota composition and its metabolites in female offspring rats, and to further elucidate its underlying mechanism and intervention targets in adult non-alcoholic fatty disease (NAFLD). The results showed that the gut microbiota of PCE female offspring at multiple time points from infancy to adolescence were significantly changed with depletion of butyric acid-producing bacteria, leading to a decrease in butyric acid in adulthood. It was also found that PCE female offspring rats were sensitive to NAFLD induced by a postnatal high-fat diet (HFD), which is mainly related to the enhancement of hepatic triglyceride synthesis function. Through mechanism exploration, we found that HFD further reduced the fecal and serum butyric acid levels in the PCE female offspring, which was significantly negatively correlated with hepatic SREBP-1c/FASN mRNA expression and triglyceride level. In vivo and in vitro experiments confirmed that sodium butyrate (NaB) supplementation could reduce hepatic lipid accumulation through MCT1/GPR109A-AMPK, thereby effectively decreasing the susceptibility to NAFLD in the PCE female offspring rats.

Objective Most both‐column acetabular fractures are combined with posterior wall fragments. However, the morphology of this posterior wall is varied, and how to fix this posterior wall remains a controversial topic. To investigate the morphological characteristics of posterior wall fragments of both‐column acetabular fractures and select corresponding fixation methods. Methods Data from 352 patients with acetabular fractures admitted to the level one trauma centre in our hospital between January 2006 and December 2022 were collected. The morphology of posterior wall fragments was observed and analyzed in 83 cases of both‐column acetabular fractures and classified according to the consistency of posterior wall morphology. A fracture map of the posterior wall was created on a normal template according to the three morphological types of posterior wall fragments. Finally, the high‐incidence area of the posterior wall fracture was projected onto the iliac fossa and the medial side of the posterior column to guide the fixation of the posterior wall fragment using the anterior intrapelvic approach. Results Fractures were divided into four types: I, large posterior wall fragment which was high in the ilium bone (34 cases, 41.0%); II, posterior wall fragment in the acetabular parietal region (18 cases, 21.7%); III, posterior wall marginal fracture (10 cases, 12.0%); and IV, non‐combined posterior wall fracture (21 cases, 25.3%). The most common morphologies of the posterior wall fragments of the first two types were mapped and projected onto the anterior iliac inner plate and medial side of the posterior column, where the corresponding area could be used to guide the insertion of the internal fixation. Conclusion Both‐column acetabular fractures combined with posterior wall fractures can be divided into four types according to the morphology of the posterior wall fragment. Understanding the corresponding three‐dimensional morphology and projection position of different types of these fragments can help surgeons determine the position and orientation of internal fixation of posterior wall fractures.

Quantitatively investigating and assessing the spatiotemporal variation in the human activity intensity (HAI) and its influencing factors are crucial for coordinating regional human–land relationships and protecting the eco-environment. However, the scale, variation pattern, and driving factors of the human activity intensity in the Guangxi Beibu Gulf Zone have not yet been determined. To bridge this gap, this study focused on evaluating and analyzing the spatiotemporal variation characteristics of the HAI from 2000 to 2020 by a quantitative model based on multi-period land use data, field survey data, and statistical data. Moreover, the socioeconomic and geographical determinants were investigated using the PCA method and Geodetector model. The results showed that (1) the overall HAI value was relatively high and increased from 18.97% in 2000 to 20.06% in 2020. The HAI value in Haicheng District was always the highest and peaked at 60.78% in 2020. (2) Spatially, approximately 19.88% of the area exhibited high HAI values, and these areas were mainly distributed in urban districts, county seats, towns, and farming areas. In contrast, the areas with low HAI values were mainly concentrated in mountainous areas and natural reserves. (3) The HAI exhibited a significant spatial agglomeration effect, and HAI hot spots were concentrated mainly in areas with intense change, such as economic development zones, industrial parks, urban suburbs, and towns with added counties. (4) The HAI was affected by various influencing factors, and the explanatory power of multiple factors for the HAI change was greater than that of a single factor.

Abstract Background Accumulating evidence has demonstrated that aberrant expression of deubiquitinating enzymes is associated with the initiation and progression of Triple-negative breast cancer (TNBC). The publicly available TCGA database of breast cancer data was used to analyze the OTUD deubiquitinating family members that were correlated with survival of breast cancer and ovarian tumor domain-containing 2 (OTUD-2), or YOD1 was identified. The aim of present study was to assess YOD1 expression and function in human TNBC and then explored the underlying molecular events. Methods We detected the expression of YOD1 in 32 TNBC and 44 NTNBC samples by qRT-PCR, Western blot and immunohistochemistry. Manipulation of YOD1 expression was assessed in vitro and in vivo for TNBC cell proliferation, migration, invasion, cell-cycle and drug resistance, using colony formation assay, transwell assay, CCK8 assay, TUNEL assay, flow cytometric analysis and xenograft tumor assay. Next, proteomic analysis, Western blot, proximity ligation assay, Immunoprecipitation, and Immunofluorescence were conducted to assess downstream targets. Results It was found that YOD1 was significantly upregulated in TNBC tissues compared with non-triple-negative breast cancer (NTNBC), which was positively correlated with poor survival in TNBC patients. Knockdown of YOD1 effectively inhibited TNBC cell migration, proliferation, cell cycle and resistance to cisplatin and paclitaxel. Mechanistically, YOD1 promoted TNBC progression in a manner dependent on its catalytic activity through binding with CDK1, leading to de-polyubiquitylation of CDK1 and upregulation of CDK1 expression. In addition, YOD1 overexpression was found to be correlated with CDK1 overexpression in human TNBC specimens. Finally, in vivo study demonstrated that YOD1 knockdown or YOD1 inhibitor could inhibit CDK1 expression and suppress the growth and metastasis of TNBC tumors. Conclusion Our study highlights that YOD1 functions as an oncogene in TNBC via binding to CDK1 and mediated its stability and oncogenic activity. Interfering with YOD1 expression or YOD1 inhibitor could suppress TNBC cells in vitro and in vivo, suggesting that YOD1 may prove to be a promising therapeutic target for TNBC.

Abstract Background The present study aimed to explore the time of maximum bacterial load and main colonization knee site in bacterial infection process based on a novel rat model of septic arthritis (SA) after anterior cruciate ligament reconstruction (ACLR). Methods Ninety-five Wistar rats with unilateral ACLR, random enrolled into control surgery (CS) group; joint inject (JI) group; presoaking (PS) group, were injected with 30 μl sterile saline or 30 μl × 107 colony forming units/ml Staphylococcus aureus via the knee joint or graft with presoaked Staphylococcus aureus during ACLR, respectively. At 1, 4, 7, 11, and 14 days postoperatively, samples were harvested to evaluate progress of knee joint infection by postoperative body weight, body temperature, knee temperature, knee width, scales of tissue damage, serum inflammatory markers, microbiological counting, microcomputed tomography (Micro-CT), digital radiography, magnetic resonance imaging (MRI) examination, and scanning electron microscopy (SEM). Results No systemic infection was observed in all rats. Comparing with serum inflammatory markers, tissue scores of inflammatory reactions, bacterial counts in the CS group, these data were significantly elevated in the JI group and PS group. The bone mass around the bone tunnel was lower and the soft tissue of knee showed more obvious swelling on MRI in the infection groups than that in the CS group at 7 and 14 days postoperatively. Staphylococcus aureus clusters on the surface of screw and graft were observed in the infection group. The whole colony forming units of Staphylococcus aureus maintained a continuous upward trend peaking 7 and 11 days followed by a balanced curve in the infection groups. Bone and soft tissue were found to have more bacterial counts than graft and screws. Conclusion This animal model effectively mimics the acute knee infection after ACLR. We found that the bacterial colonization exhibited the peak of acute infection between 7 and 11 days postoperatively, with the major bacteria loads found in the bone, soft tissue.

Abstract Background Systemic vancomycin administration pre-operatively for the infection prophylaxis of spinal implant surgery remains unsatisfactory. This study aimed to explore the efficacy and dosage of local use of vancomycin powder (VP) in preventing surgical site infections after spinal implant surgery in a rat model. Methods Systemic vancomycin (SV; intraperitoneal injection, 88 mg/kg) or intraoperative intra-wound VP (VP0.5: 44 mg/kg, VP1.0: 88 mg/kg, VP2.0: 176 mg/kg) was applied after spinal implant surgery and methicillin-resistant S. aureus (MRSA; ATCC BAA-1026) inoculation in rats. General status, blood inflammatory biomarkers, microbiological and histopathological evaluation were performed during 2 weeks post-surgery. Results No post-surgical deaths, wound complications and obvious signs of vancomycin adverse effects were observed. Bacterial counts, blood and tissue inflammation were reduced in the VP groups compared with the SV group. VP2.0 group showed better outcomes in weight gain and tissue inflammation than the VP0.5 and VP1.0 group. Microbial counts indicated that no bacteria survived in the VP2.0 group, whereas MRSA was detected in VP0.5 and VP1.0 groups. Conclusions Intra-wound VP may be more effective than systemic administration in preventing infection caused by MRSA (ATCC BAA-1026) after spinal implant surgery in a rat model.

Abstract Background Recent studies have shown that bone marrow stromal cell-derived exosomes (BMSC-Exos) can be used for tissue repair. However, whether the BMSC-Exos can promote tendon-bone healing after anterior cruciate ligament reconstruction (ACLR) is still unclear. In this study, we observed in vivo and in vitro the effect of rat BMSC-Exos on tendon-bone healing after ACLR and its possible mechanism. Methods Highly expressed miRNAs in rat BMSC-Exos were selected by bioinformatics and verified in vitro. The effect of overexpressed miRNA in BMSC-Exos on M2 macrophage polarization was observed. A rat model of ACLR was established. The experimental components were divided into three groups: the control group, the BMSC-Exos group, and the BMSC-Exos with miR-23a-3p overexpression (BMSC-Exos mimic) group. Biomechanical tests, micro-CT, and histological staining were performed for analysis. Results Bioinformatics analysis showed that miR-23a-3p was highly expressed in rat BMSC-Exos and could target interferon regulatory factor 1 (IRF1, a crucial regulator in M1 macrophage polarization). In vitro, compared with the control group or the BMSC-Exos group, the BMSC-Exos mimic more significantly promoted the polarization of macrophages from M1 to M2. In vivo, at 2 weeks, the number of M2 macrophages in the early local stage of ACLR was significantly increased in the BMSC-Exos mimic group; at 4 and 8 weeks, compared with the control group or the BMSC-Exos group, the bone tunnels of the tibia and femur sides of the rats in the BMSC-Exos mimic group were significantly smaller, the interface between the graft and the bone was narrowed, the bone volume/total volume ratio (BV/TV) increased, the collagen type II alpha 1 level increased, and the mechanical strength increased. Conclusions BMSC-Exos promoted M1 macrophage to M2 macrophage polarization via miR-23a-3p, reduced the early inflammatory reaction at the tendon-bone interface, and promoted early healing after ACLR.

Aims: Treatment outcomes for methicillin-resistant Staphylococcus aureus (MRSA) periprosthetic joint infection (PJI) using systemic vancomycin and antibacterial cement spacers during two-stage revision arthroplasty remain unsatisfactory. This study explored the efficacy and safety of intra-articular vancomycin injections for PJI control after debridement and cement spacer implantation in a rat model. Methods: Total knee arthroplasty (TKA), MRSA inoculation, debridement, and vancomycin-spacer implantation were performed successively in rats to mimic first-stage PJI during the two-stage revision arthroplasty procedure. Vancomycin was administered intraperitoneally or intra-articularly for two weeks to control the infection after debridement and spacer implantation. Results: Rats receiving intra-articular vancomycin showed the best outcomes among the four treatment groups, with negative bacterial cultures, increased weight gain, increased capacity for weightbearing activities, increased residual bone volume preservation, and reduced inflammatory reactions in the joint tissues, indicating MRSA eradication in the knee. The vancomycin-spacer and/or systemic vancomycin failed to eliminate the MRSA infections following a two-week antibiotic course. Serum vancomycin levels did not reach nephrotoxic levels in any group. Mild renal histopathological changes, without changes in serum creatinine levels, were observed in the intraperitoneal vancomycin group compared with the intra-articular vancomycin group, but no changes in hepatic structure or serum alanine aminotransferase or aspartate aminotransferase levels were observed. No local complications were observed, such as sinus tract or non-healing surgical incisions. Conclusion: Intra-articular vancomycin injection was effective and safe for PJI control following debridement and spacer implantation in a rat model during two-stage revision arthroplasties, with better outcomes than systemic vancomycin administration. Cite this article: Bone Joint Res 2022;11(6):371–385.

Abstract Background Intra-wound vancomycin powder (VP) has been used in clinical practice to prevent periprosthetic joint infection (PJI) after primary knee/hip arthroplasty. The role of intra-wound VP in the setting of debridement and implant exchange after PJI remains undefined. This study aimed to explore the efficacy and safety of intra-wound VP in the control of methicillin-resistant S. aureus (MRSA) infection after debridement and implant exchange. Methods PJI modeling by knee prosthesis implantation and MRSA inoculation, debridement and implant exchange were performed in Wistar rats successively to mimic the one-stage exchange arthroplasty of PJI patients. Two weeks of systemic vancomycin (SV) or/and intraoperative intra-wound VP of single dosage were applied after revision surgery. Results No post-surgery deaths, incision complications and signs of drug toxicity were observed. The microbial counts of SV or intra-wound VP group were significantly reduced compared with the control group, while bacteria were still detected on the bone, soft-tissue and prosthesis. The elimination of bacterial counts, along with improvement of tissue inflammation and serum inflammatory markers, were observed in the rats with SV plus intra-wound VP. Serum levels of vancomycin in all groups were lower than that of causing nephrotoxicity, while no statistic difference was observed in the serum biochemical marker among the groups. Conclusions Intra-wound VP is effective after debridement and implant exchange in our current rat PJI model. Neither SV nor intra-wound VP alone could eradicate the bacteria within a two-weeks treatment course, while SV plus intra-wound VP could eliminate the MRSA infection, without notable hepatic or renal toxicity and any incision complications.

Metal Magnetic Memory (MMM) exhibits the advantage of not requiring embedded sensors or external excitation, making it suitable for inspecting ferromagnetic components in engineering structures. This study introduced MMM into stress detection of steel strands. Graded tensile tests were conducted on the steel strands to investigate the correlation between Self-Magnetic Flux Leakage (SMFL) signals and stress levels. Different spatial detection positions with varying Lift-Off Values (LOV) and Rotation Angle Values (RAV) were set to examine the distribution of spatial SMFL field under load. Furthermore, a magnetic characteristic parameter AN was proposed to assess the stress level of the steel strands. The results indicate that the rate of change in the middle region of the SMFL curve was lower than that at the beginning and the end. Additionally, with increased applied load, the SMFL curve exhibited systematic variations, and the dispersion of the normal component curve gradually decreased. By utilizing the magnetic characteristic parameter AN, the stress in the steel strands can be calculated, with the parameters determined based on LOV and RAV. This achievement expanded the nondestructive testing methods for steel strands and holds significant research value.

The damage monitoring and identification of arch bridges provide an important means to ensure the safe operation of arch bridges. At present, many methods have been developed, and the applicability and effectiveness of these methods depend on the damage type, structural configuration and available data. To guide the practical application of these methods, a systematic review is implemented in this paper. Specifically, the damage monitoring and identification methods of arch bridges are divided into the damage monitoring of local diseases and damage identification of overall performance. Firstly, the research on the damage monitoring of the local diseases of arch bridges is reviewed. According to the disease type, it is divided into four categories, including suspender inspection, void monitoring, stress detection and corrosion detection. For each disease, this paper analyzes the principles, advantages and shortcomings of various methods. Then, the damage identification methods of the overall performance of arch bridges are reviewed, including masonry arch bridges, steel arch bridges, reinforced concrete arch bridges and concrete-filled steel tubular arch bridges. And the commonly used damage indexes of damage identification methods are summarized. This review aims to help researchers and practitioners in implementing existing damage detection methods effectively and developing more reliable and practical methods for arch bridges in the future.

Abstract Background Venous thromboembolism (VTE) is a potentially fatal complication after arthroplasty. Numerous prophylactic strategies and studies to reduce VTEs have focused on the duration of the hospital stay and on few extramural hospitals. This study aimed to investigate extramural hospital management of VTE after total hip/knee arthroplasty (THA/TKA) in China with a novel survey tool. Methods A total of 180 patients undergoing arthroplasty, including 68 THA patients and 112 TKA patients, were enrolled in this study. All patients received anticoagulant treatment management. A survey querying VTE management and adherence, such as therapy information, understanding of anticoagulation, satisfaction with the ability of medical staff, and satisfaction with health care costs, was administered by a questionnaire (TKA/THA Patients’ Experience with Anticoagulation in the Post-discharge Period) for quality improvement. Results The average age of the patients was 65.27 ± 13.62 years. All patients knew their follow-up times. 85 % of them were suggested that re-examine at the next 14 days, and the others at the next 28 days. All patients continued to visit the orthopaedic clinic after discharge without choosing other types of outpatient services, such as an anticoagulant clinic or home visit with a nurse/pharmacist or remote evaluation by telephone. A total of 96.6 % of all patients used new oral anticoagulants, and the most common treatment duration was 2–4 weeks (93.3 %). 48 % informed their physicians that they were taking anticoagulation medications when they visited ophthalmology, dentistry, dermatology, and other departments. The overall rate of satisfaction with anticoagulation management was 81.67 %, and 6.67 % of patients were not unsatisfied with their medical expenses. Patient compliance decreased with increasing follow-up time. Continuous follow-ups after discharge significantly improved patient compliance. Conclusions These results elucidate how we can improve the quality of anticoagulation. Continuous follow-up appointments for 30 days after discharge, especially for individuals over 65 years old, significantly improved patient satisfaction and reduced the incidence of VTE and medical costs.

Study region: The Nanliu River Basin in Beibu Gulf, China. Study focus: The variations in water discharge and sediment load were analysed for 1961–2015. In addition, sediment retention by high-density small water conservancy facilities in the tributaries was estimated by a hydrological model with different scenarios. At the end of the study, the variation in the relationship between water discharge and suspended sediment concentration (SSC) and the impact on riverbeds were analysed. New hydrological insights for the region: The sediment load showed a dramatically decreasing trend, and an abrupt change point in 1988 was detected by a Mann–Kendall test. Compared to the baseline period (1961–1988), the sediment load in the altered period (1989–2015) decreased by 41.7%. By employing the SWAT model with different scenarios, sediment retention by high-density small water conservancy facilities in the tributaries was estimated in the basin, with a mean value of 457.1 × 103 tons/yr during the altered period. The construction of water conservancy facilities has been the key driver of the significant reduction in sediment load observed in the Nanliu River. The rating curves of monthly SSC–discharge showed clockwise patterns, which were different from the Yangtze River’s counter-clockwise pattern. SSC reductions and excessive sand mining in the main channel have strongly affected riverbeds, leading to a year-by-year drop.

Concentrated solar power generation technology is one of the most important approach of the solar thermal utilization due to its stability, controllability and high capacity. The photon-thermal conversion efficiency of the solar concentrator is the main factor that influence the power generation capacity and the photon-electric conversion efficiency of the concentrated solar thermal power station. In this paper, the recent key technologies of improving the optical-thermal conversion performance of the solar concentrators were summarized via three aspects, including optical structures, receiver structures and heat transfer fluid. The advanced optimization strategy and the performance improvements of the concentrators, as well as the limitation, were presented. On the basis referred, the perspective of the solar concentrator technologies was analyzed.

Background: The geographic distribution of osteochondroma (OC) varies greatly around the world. There has been no recent report on OC in a large Chinese population. The aim of this study was to characterize OC by an epidemiological analysis of the clinical data from one medical institution in South China. Methods: We searched medical electronic records from January 2001 to January 2016 in one large hospital in South China to identify patients with a definite diagnosis of OC. Their epidemiological data were collected and analyzed statistically, including gender, tumor site, age at first diagnosis and symptoms, local recurrence and malignant transformation. Differences between genders and between solitary osteochondroma (SO) and multiple osteochondroma (MO) were particularly analyzed. Results: A total of 431 OC patients (291 males and 140 females; 329 SOs and 102 MOs) were identified. The gender ratio was 2.08 with a male predominance. OCs were mostly located around the knee (250 cases). 280 patients were in their 0s to 20s upon first diagnosis. The average age at the time of first diagnosis was 20.63 years for all, 18.47 years for males and 25.11 years for females (P=0.000). OC recurred locally in 35 patients (15 SOs and 20 MOs), with a significant difference between SO/MO (P=0.000) but not between genders (P=0.100). The average interval from the primary surgery to local or malignant recurrence was 37.41 months. Malignant transformation was found in 5 patients (4 males and 1 female), showing no gender difference (P=0.549). Conclusions: OC may have a male predominance in Chinese population. It mostly occurred at 0–20 years of age and around the knee. Upon the first diagnosis of OC, the males tended to be younger than the females, and so did the MO patients than the SO ones. In addition, MO had a higher incidence of local recurrence. Intervals from primary surgery to local recurrence or malignant transformation in MO patients were longer than in SO patients.

Abstract Background Herbal quality is strongly influenced by harvest time. It is therefore one of crucial factors that should be well respected by herbal producers when optimizing cultivation techniques, so that to obtain herbal products of high quality. In this work, we paid attention on one of common used Chinese herbals, Cyathula officinalis Kuan. According to previous studies, its quality may be related with growth years because of the variation of several main bioactive components in different growth years. However, information about the whole chemical composition is still scarce, which may jointly determine the herbal quality. Methods Cyathula officinalis samples were collected in 1–4 growth years after sowing. To obtain a global insight on chemical profile of herbs, we applied a metabolomics approach based on gas chromatography–mass spectrum. Analysis of variance, principal component analysis, partial least squares discriminant analysis and hierarchical cluster analysis were combined to explore the significant difference in different growth years. Results 166 metabolites were identified by using gas chromatography–mass spectrum method. 63 metabolites showed significant change in different growth years in terms of analysis of variance. Those metabolites then were grouped into 4 classes by hierarchical cluster analysis, characterizing the samples of different growth ages. Samples harvested in the earliest years (1–2) were obviously differ with the latest years (3–4) as reported by principal component analysis. Further, partial least squares discriminant analysis revealed the detail difference in each growth year. Gluconic acid, xylitol, glutaric acid, pipecolinic acid, ribonic acid, mannose, oxalic acid, digalacturonic acid, lactic acid, 2-deoxyerythritol, acetol, 3-hydroxybutyric acid, citramalic acid, N-carbamylglutamate, and cellobiose are the main 15 discrimination metabolites between different growth years. Conclusion Harvest time should be well considered when producing C. officinalis. In order to boost the consistency of herbal quality, C. officinalis is recommended to harvest in 4th growth year. The method of GC–MS combined with multivariate analysis was a powerful tool to evaluate the herbal quality.

A novel SPR biosensor that can achieve a high sensitivity is proposed; therefore, a new prism coupling structure based on metal nanowires array layer is designed in this paper. The thickness of each medium layer for the structure is analyzed to obtain the optimal SPR spectrum, by the finite element method, so that the sensitivity is able to be enhanced greatly. The optimal thicknesses of each medium layer are given, and the sensitivity of the SPR biosensor can reach as high as 210.75°/RIU for the refractive index of the sensing medium, from 1.30 to 1.38.

Study region: The source region of the Yellow River (SRYE) in the northeastern Tibetan Plateau. Study focus: The spatial-temporal changes of hydrological and meteorological variables and their linkages over the SRYE were investigated for 1961–2013. Meanwhile, we quantified the impacts of precipitation and evapotranspiration on hydrological changes through climate elasticity by applying a land surface hydrological model. Furthermore, the impacts of warming climate on the seasonal snow cover and spring flow over the SRYE were examined. New hydrological insights for the region: Decreased precipitation and lightly increased evapotranspiration both contributed to reduced runoff in the 1990s, with the decreased precipitation playing a more important role (70%) than the increased evapotranspiration (30%). In the 2000s, precipitation contributed 3% to the runoff reduction, while the increased evapotranspiration accounted for 97%. Along with rapid warming, evapotranspiration is playing an increasingly important role in affecting runoff changes in the SRYE. During 2001–2012, snow cover in May decreased over the region. Spring peak flow mainly caused by snowmelt occurred earlier for about 15 days at the Jimai hydrological station due to an earlier snow melt associated with the climate warming in the past 3 decades.

The energy evolution behaviour and mesodamage mechanism of CRC (crumb rubber concrete) were investigated by laboratory experiments and numerical simulations. The mesoscopic physical and mechanical parameters of CRC (crumb rubber concrete) materials were analyzed and determined by the discrete element method and trial-and-error method, and the mechanism and evolution of microcracks propagation during CRC failure were studied based on the parallel-bond model. The relationship among dissipation energy, damage threshold, and rubber content during CRC damage was studied by adopting the method of microscopic energy tracking. The energy release ratio was proposed to analyze the degree of “brittleness” of CRC after reaching its peak strength. The essential mechanism of different failure characteristics of CRC and NC (normal concrete) was analyzed and discussed by referring to their correlation between the microenergy evolution rule and the constitutive curve. The results show that (1) the calibrated mesoscopic physical and mechanical parameters can better reflect the mechanical characteristics of CRC materials, (2) there is a strong correlation between the mesoscopic damage threshold of CRC with different rubber contents and the proportion of dissipation energy at the peak strength, and the damage threshold of the CRC with 25% rubber mass is the largest, (3) the relationship between elastic strain energy release ratio of CRC and rubber particle contents can be fitted by the negative exponential function, and (4) the essential reasons for the different destruction characteristics of CRC and NC is that the addition of rubber particles makes more external input energy to be converted into dissipative energy required for microcracks propagation and sliding friction between particles and released step by step.

Due to the high elevation, complex terrain, severe weather, and inaccessibility, direct meteorological observations do not exist over large portions of the Tibetan Plateau, especially the western part of it. Satellite rainfall estimates have been very important sources for precipitation information, particularly in rain gauge-sparse regions. In this study, Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) products 3B42, RTV5V6, and RTV7 were evaluated for their applicability to the upper Yellow and Yangtze River basins on the Tibetan Plateau. Moreover, the capability of the TMPA products to simulate streamflow was also investigated using the Variable Infiltration Capacity (VIC) semi-distributed hydrological model. Results show that 3B42 performs better than RTV5V6 and RTV7, based on verification of the China Meteorological Administration (CMA) observational precipitation data. RTV5V6 can roughly capture the spatial precipitation pattern but overestimation exists throughout the entire study region. The anticipated improvements of RTV7 relative to RTV5V6 have not been realized in this study. Our results suggest that RTV7 significantly overestimates the precipitation over the two river basins, though it can capture the seasonal cycle features of precipitation. 3B42 shows the best performance in streamflow simulation of the abovementioned satellite products. Although involved in gauge adjustment at a monthly scale, 3B42 is capable of daily streamflow simulation. RTV5V6 and RTV7 have no capability to simulate streamflow in the upper Yellow and Yangtze River basins.

The seasonal warming over the southwestern Yellow Sea (YS) in the spring is of vital importance to the local ecologic environment, especially to the massive green algae blooms of the YS in late spring and early summer. Based on daily optimum interpolation sea surface temperature (SST) data consisting of satellite derived SST from Advanced Very High Resolution Radiometer (AVHRR) and in situ measurements, this study analyzed the spring SST variation over the southwestern YS (SWYS) from 1982 to 2018. The results show that the recent warming trend of spring SST over the SWYS is four-to-six times that of the global average, and as a result, sea water over the Subei Shoal (SBS) shifts about 10−13 days earlier to reach 10 °C in early April. This implies that, accordingly, the micro-propagules of green algae over the SBS may have the chance to germinate earlier. SST variability in early April significantly correlates with northerly wind and exhibits a general warming over the SWYS with an intensified warming anchored along the axis of the submarine canyon off the Yangtze estuary. The Moderate Resolution Imaging Spectroradiometer (MODIS) red−green−blue composite images captured the intrusion of the Taiwan Warm Current (TWC) into the SWYS through the submarine canyon during northerly wind relaxation in early April. Ocean remote sensing provides important clues for understanding the regional SST variability in the SWYS. Following this clue, this study finds that the weakening of winter monsoon in the spring leads to northward migration of the TWC and results in enhanced spring warming over the SWYS. The attendant advanced warming in spring, resulting in a favorable temperature condition for early development of green alga, may have contributed to the green tide blooms in the Yellow Sea in the recent decade.

The two benzene rings in the cation of the title compound, C15H18N4O22+·2NO3−·2H2O, are almost perpendicular [dihedral angle = 91.6 (2)°]. In the crystal, the components are linked by O—H...O, N—H...O and C—H...O hydrogen bonds.

The asymmetric unit of the title compound, C8H9N2+·C8H5O4−, contains two independent ion pairs. In each 2-methyl-1H-benzimidazolium ion, an intramolecular O—H...O bond forms an S(7) graph-set motif. In the crystal, the components are linked by N—H...O hydrogen bonds, forming chains along [210]. Further stabilization is provided by weak C—H...O hydrogen bonds.

Bulk phosphorus oxynitride (PON), isoelectronic with SiO2, is confirmed to have many polymorphs as the latter. However, its 2D counterparts have not been studied. In this work, crystal structure exploration and property study are performed on 2D PON with the help of first‐principle calculation. Three 2D PON sheets are found with thermal, dynamical, and mechanical stability and all of them can be viewed as oxygen‐doped known 2D γ phosphorus nitride (γ‐PN). In the studies, it is indicated that they are indirect bandgap materials with gap values larger than 3 eV. The situations of orbital hybridization are discussed and their bonding properties are analyzed. Infrared vibrational spectra of these 2D materials are simulated and the vibrational modes at the Brillouin center are assigned by the factor group analysis. The reasons for the disappearance of some infrared peaks in the simulated spectra are revealed based on the calculated Born effective charges and vibrational eigenvectors. Their piezoelectric stress tensors are computed via density‐functional perturbation method and the piezoelectric strain tensors are also deduced via the calculated elastic constants. In the results, it is uncovered that these 2D PON sheets have considerably greater piezoelectric coefficients than the primitive 2D γ‐PN, which make them promising for nanopiezoelectric use. [ABSTRACT FROM AUTHOR]