Remarkable Negative Correlation Research Articles

Impact of landscape patterns on ecosystem services in China: a case study of the central plains urban agglomeration

Urban agglomeration is the highest stage of urban development, which reasonable planning will be conducive to the rapid and healthy development of the regional economy. However, in recent years, unreasonable urban agglomeration planning has changed landscape patterns and brought huge challenges to ecosystem services. Moreover, there is currently a lack of understanding of the relationship between landscape patterns and ecosystem services, especially in the process of urban agglomeration construction. In this study, we attempt to reveal the impact of landscape patterns on ecosystem services value (ESV) based on many years of remote sensing data in the Central Plains Urban Agglomeration (CPUA). The results show that landscape patterns have significant spatiotemporal evolution characteristics, and there are significant differences between different landscape patterns in the CPUA. Moreover, most of landscape patterns show significant east-west differences. Total ESV has decreased from USD 838.53 million in 2000 to USD 792.32 million in 2018. From a spatial perspective, the areas with high ESV are mostly distributed in the western mountainous and southern hilly areas, but low ESV area are mainly concentrated in the central and northern plains. In addition, the results of model analysis reveal that there is a remarkable positive correlation between ESV and patch density, interspersion juxtaposition index, cohesion index, and splitting index, but a remarkable negative correlation between ESV and total edge. These results provide critical guidance and suggestions for the improvement of future urban agglomeration construction.

Effects of resourcefulness on internet game addiction among college students: The mediating role of anxiety and the moderating role of gender.

The mechanism of internet game addiction is unclear. Whether anxiety mediates between resourcefulness and internet game addiction and whether gender affect its mediation role have not been studied previously. A total of 4,889 college students from a college in southwest China were included in this study to complete the investigation, in which three questionnaires were used for evaluation. Pearson's correlation analysis indicated a remarkable negative correlation between resourcefulness with internet game addiction and anxiety, as well as a significant positive correlation between anxiety and this addiction. The structural equation model confirmed the mediation role of anxiety. The multi-group analysis confirmed the moderating role of gender in the mediation model. These findings have advanced the results of existing studies, indicating the buffering effect of resourcefulness on internet game addiction and revealing the potential mechanism of this relationship.

Modeling and analysis of the transmission dynamics of cystic echinococcosis: Effects of increasing the number of sheep.

A transmission dynamics model with the logistic growth of cystic echinococcus in sheep was formulated and analyzed. The basic reproduction number was derived and the results showed that the global dynamical behaviors were determined by its value. The disease-free equilibrium is globally asymptotically stable when the value of the basic reproduction number is less than one; otherwise, there exists a unique endemic equilibrium and it is globally asymptotically stable. Sensitivity analysis and uncertainty analysis of the basic reproduction number were also performed to screen the important factors that influence the spread of cystic echinococcosis. Contour plots of the basic reproduction number versus these important factors are presented, too. The results showed that the higher the deworming rate of dogs, the lower the prevalence of echinococcosis in sheep and dogs. Similarly, the higher the slaughter rate of sheep, the lower the prevalence of echinococcosis in sheep and dogs. It also showed that the spread of echinococcosis has a close relationship with the maximum environmental capacity of sheep, and that they have a remarkable negative correlation. This reminds us that the risk of cystic echinococcosis may be underestimated if we ignore the increasing number of sheep in reality.

Geo-Distributed IoT Data Analytics With Deadline Constraints Across Network Edge

Owing to the advancement of the Internet of Things (IoT) and 5G mobile technologies, various IoT devices produce massive data, which is usually transferred to nearby sites, such as edge nodes or datacenters. Many large-scale IoT applications need to analyze the data distributed across multiple sites to obtain final results. A dominant challenge of this type of data analytics is the heterogeneities of resource capacities across geo-distributed sites. In this article, we find that the resource capacity as well as the resource price differ among sites, and the price heterogeneity has a significant impact on geo-distributed IoT data analytics. Thus, each geo-distributed IoT data analytics job prefers to minimize the job execution cost while guaranteeing its deadline requirement under the resource constraints of involved sites. Specifically, we propose to jointly consider the resource heterogeneities of both capacity and price, and minimize the cost of each job before its deadline. We characterize this optimization problem as a quadratically constrained quadratic programming problem. To tackle such an NP-hard problem, we propose the minimize the job completion cost before a given deadline (MCGL) method, which calculates a task placement solution by the gradient adjustment strategy according to the remarkable negative correlation relationship between job completion time and job completion cost of geo-distributed IoT data analytics job. The task placement strategy can optimize resource cost with respect to the deadline requirement of any geo-distributed data analytics job. The trace-driven evaluations indicate that MCGL significantly reduces the total cost compared with existing methods; moreover, they satisfy the deadline constraints simultaneously.

Effects of Aspirin Therapy on Bypass Efficacy and Survival of Patients Receiving Direct Cerebral Revascularization.

Background: Both patency maintenance and neoangiogenesis contribute to cerebrovascular bypass efficacy. However, the combined impact of the aforementioned two indicators on postoperative revascularization following superficial temporal artery-to-middle cerebral artery (STA-MCA) bypass has been less well elucidated. Meanwhile, there is a paucity of evidence with conflicting results about postoperative aspirin therapy. Objective: The objective of the study was to investigate the correlation between aspirin use and STA-MCA bypass efficacy, including patency, postoperative neoangiogenesis, and follow-up outcomes. Methods: A total of 181 MMD patients (201 procedures) undergoing STA-MCA bypass at our institution (2017–2019) were retrospectively reviewed. The bypass efficacy level and postoperative complications were compared between aspirin and non-aspirin groups. Results: Among 95 PS-matched pairs, the aspirin group presented a significantly more favorable bypass efficacy than the non-aspirin group [odds ratio (OR) 2.23, 95% confidence interval (CI) 1.11–4.61; p = 0.026]. Multivariate logistic regression analysis confirmed the profound impact of aspirin as an independent predictor of bypass efficacy [adjusted OR 2.91, 95% CI 1.34–6.68; p = 0.009]. A remarkable negative correlation was found between bypass efficacy and the rate of ischemic complications (Phi = −0.521). Postoperative aspirin therapy was associated with a non-significant trend toward a lower incidence of ischemic events [OR 0.73, 95% CI 0.23–2.19; p = 0.580]. No significant difference in bleeding rates was observed between aspirin and control groups [OR 1.00, 95% CI 0.12–8.48; p = 1.000]. Conclusion: Among patients undergoing STA-MCA bypass procedures, bypass efficacy is a good predictor of follow-up outcomes. Postoperative aspirin therapy can improve patency, neoangiogenesis, and overall bypass efficacy, thereby protecting against postoperative ischemic complications. Clinical Trial Registration: http://www.chictr.org.cn/, identifier CTR2100046178.

Integrative Multi-Omics Analysis of Identified SKA3 as a Candidate Oncogene Correlates with Poor Prognosis and Immune Infiltration in Lung Adenocarcinoma.

BackgroundSpindle and kinetochore-associated complex subunit 3 (SKA3) plays important roles in promoting the migration and the invasion of various human cancer cells. There are a few studies on SKA3 in lung adenocarcinoma (LUAD), but the in-depth analysis of the expression of SKA3 and the correlated possible immune mechanism of SKA3 in LUAD are not clear.MethodsIn our study, the expression and survival data of SKA3 were analyzed in LUAD using TIMER, Oncomine, UALCAN, cBioPortal, LinkedOmics, Human Protein Atlas, and Kaplan–Meier plotter. Then, quantitative PCR was used to verify the expression differences of SKA3 between LUAD tissues of mice and the normal tissues.ResultsWe established that the expression of SKA3 in the LUAD group was remarkably higher than that in the normal group. Additionally, high SKA3 expression was linked to poorer survival in LUAD. Moreover, SKA3 expression had a remarkable negative correlation with the immune infiltration of B cells, macrophages, and CD4+ T cells. SKA3 was markedly negatively related to the immune type biomarkers of T cells and B cells in LUAD. The elevated expression of SKA3 with LUAD in enriched B cells, CD4+ T cells, CD8+ T cells, macrophages and Treg cells had worse prognosis, respectively. Functional network analysis showed that SKA3 regulated the mitotic cell cycle, mitosis, chromosome segregation and cell division via pathways.ConclusionIn summary, our study suggested that SKA3 was highly expressed in LUAD and SKA3 might function as a prognostic biomarker in LUAD. Besides, SKA3 may be a candidate oncogene, which correlates with poor prognosis and immune infiltration in lung adenocarcinoma.

Growth response of seven multipurpose tree species to climatic factors: A case study from northwestern Himalayas, India

Identification of the species for dendrochronological studies is of great relevance to understand various aspects of climate change. However, in the northwestern Himalayan region, dendroclimatological investigations are confined to conifer species, with broadleaved species being disregarded. Thus, the present study was conducted to assess the growth response of seven multipurpose tree species (MPTs), namely Bauhinia variegata, Celtis australis, Grewia optiva, Paulownia fortunei, Toona ciliata, Ulmus villosa and Melia composita to local climate variables, viz. temperature as well as rainfall (seasonal, monthly, average) and CO2 level by evaluating the climatic signal in tree ring chronologies at Solan district, India (altitude 1 250 m) in the mid-hills of the northwestern Himalayas. The results indicated that only the maximum, rainy season temperature and CO2 level varied significantly (P < 0.05) between 1991 and 2017. Only G. optiva exhibited a significant (P < 0.05) tendency toward increased growth. C. australis has a remarkable negative correlation with temperature variables, viz. average, maximum, spring season, March temperature, whereas T. ciliata exhibits a positive correlation with temperature variables, such as rainy season, average and April temperature. Similarly, winter, total and December rainfall have a profound effect on P. fortunei, while March rainfall adversely affected the growth of B. variegata. On the other hand, G. optiva demonstrated sensitivity to both temperature (February and May) and rainfall variables (winter, February and May). U. villosa recorded a positive correlation with rainfall (autumn and October rainfall) but a negative correlation with temperature variables (maximum and April temperature). Elevated CO2 levels affected only two species (G. optiva, M. composita) out of the seven selected species. Our findings will contribute to a better understanding of the climate growth relationships of investigated tree species, as a result, to more accurate projections of the effects of climate change on these MPTs and directing future studies.

Impact of Helmet-Wearing Policy on E-Bike Safety Riding Behavior: A Bivariate Ordered Probit Analysis in Ningbo, China.

At present, Chinese authorities are launching a campaign to convince riders of electric bicycles (e-bikes) and scooters to wear helmets. To explore the effectiveness of this new helmet policy on e-bike cycling behavior and improve existing e-bike management, this study investigates the related statistical distribution characteristics, such as demographic information, travel information, cycling behavior information and riders’ subjective attitude information. The behavioral data of 1048 e-bike riders related to helmet policy were collected by a questionnaire survey in Ningbo, China. A bivariate ordered probit (BOP) model was employed to account for the unobserved heterogeneity. The marginal effects of contributory factors were calculated to quantify their impacts, and the results show that the BOP model can explain the common unobserved features in the helmet policy and cycling behavior of e-bike riders, and that good safety habits stem from long-term safety education and training. The BOP model results show that whether wearing a helmet, using an e-bike after 19:00, and sunny days are factors that affect the helmet wearing rate. Helmet wearing, evenings during rush hour, and picking up children are some of the factors that affect e-bike accident rates. Furthermore, there is a remarkable negative correlation between the helmet wearing rate and e-bike accident rate. Based on these results, some interventions are discussed to increase the helmet usage of e-bike riders in Ningbo, China.

Analysis of improvements in MOPITT observational coverage over Canada

Abstract. The Measurements of Pollution in the Troposphere (MOPITT) satellite instrument has been measuring global tropospheric carbon monoxide (CO) since March 2000, providing the longest nearly continuous record of CO from space. During its long mission, the data processing algorithms have been updated to improve the quality of CO retrievals and the sensitivity to the lower troposphere. Currently, MOPITT retrievals are only performed for clear-sky observations or over low clouds for ocean scenes. The cloud detection scheme was modified in the new V9 product, resulting in an improvement in observational coverage, especially over land. Comparison of the spatial and seasonal variations of the data coverage in V9 and V8 shows differences with significant geographical and temporal variability, with some regions such as Canada and the Amazon exhibiting a doubling of data in winter. Here we conducted an analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) cloud heights and cloud mask products along with MOPITT retrieval cloud flag descriptors to understand the impact of cloud conditions on the MOPITT observational coverage, with a particular focus on observations over Canada. The MOPITT CO total column (TC) data were modified by turning off the cloud detection scheme to allow for a CO retrieval result, regardless of their cloud status. Analyses of the standard V8 CO TC product (cloud filtered) and non-standard product (non-cloud-masked) were conducted for selected days. Results showed some coherent structures that were observed frequently in the non-masked CO product that was not present in the V8 product and could potentially be actual CO features. Many times, these CO plumes were also seen in the Infrared Atmospheric Sounding Interferometer (IASI) CO TC product. The MODIS cloud height analysis revealed that a significant number of low-cloud CO retrievals were discarded in the V8 product. Most of the missed CO plumes in the V8 product are now detected in the new V9 product as a result of the dependence of the MOPITT radiance ratio (MRT) test over land. Comparisons of the MRT and MODIS cloud height data indicate a remarkable negative correlation. As a result of the modified V9 cloud detection algorithm, a significant portion of the low-cloud CO retrievals is now incorporated in the new V9 MOPITT product. Consequently, the observational coverage over Canada is significantly improved, which benefits analyses of regional CO variability, especially during extreme pollution events. We also conducted a comparison of MOPITT and IASI CO TC and found generally good agreement, with about a 5 %–10 % positive bias that is more pronounced in highly polluted scenes.

Effects of nitrogen addition on root traits and soil nitrogen in the long-term restored grasslands

Fine root traits are plastic and responsive to increased nitrogen (N) deposition. However, with the restoring of the ecosystem after grain for green, little research has been reported about the response of root traits in a long-term restored ecosystem to increased N deposition. Therefore, a successive N addition experiment was conducted in a long-term restored grassland on the Loess Plateau to analyse the effects of different N addition levels (0, 2.5, 5, 10, 20 g N/m<sup>2</sup>/year) on root morphological traits, soil carbon (C) and N. Our results showed that root morphological traits (except for root diameter) firstly increased and then declined, with the maximum in the N level of 5 g/m<sup>2</sup>/year. N addition significantly increased soil organic carbon, total nitrogen, ammonium nitrogen (NH<sub>4</sub><sup>+</sup>-N) and nitrate-nitrogen (NO<sub>3</sub><sup>–</sup>-N) with the increasing N addition level, especially in the soil surface layer. Specific root length and specific root area had remarkable negative correlations with NO<sub>3</sub><sup>–</sup>-N, while root diameter and root length density had positive correlations with soil availability N and soil microbial biomass carbon. This study indicated that plants could have the threshold response to adapt to the N addition and prefer to slowly grow rather than quickly invest and return in order to adapt to the environmental stress.

The applicability of different tobacco types to heated tobacco products

Heated tobacco (Nicotiana tabacum L.) products develop rapidly because of its low toxicity. In order to evaluate the industrial applicability of the existing types of characteristic tobacco as raw materials for heated tobaccos, this research ascertained differences in the main chemical compositions in tobacco leaves from different types to establish a relationship between chemical composition and sensory evaluation to select types suitable for producing heated tobaccos. Nine tobacco types (K326, Yunyan 97, Cherry-red tobacco, Han tobacco, Dao tobacco, Tiandeng tobacco, Sun-cured yellow tobacco, fresh-cut tobacco, and aromatic tobacco) planted in Yunnan Province, China were selected. Their sensory quality was evaluated by the method for sensory evaluation of heated tobaccos and chemical composition and content of aroma substances in tobacco leaves were determined. In the evaluation of sensory quality of heated tobaccos, the total score of Tiandeng tobacco was significantly higher than those of the other types, followed by Cherry-red tobacco and K326; There were significant differences in chemical composition in the nine tobacco types and the total alkaloid content in Cherry-red tobacco was notably higher than in the other tobacco types. The amounts of total sugar, reducing sugar, and starch in Han tobacco were significantly lower than other types, while the amounts of total nitrogen, potassium oxide, chloride ions, and protein were much higher than in the other tobacco types. The total amounts of polyphenols and aroma compounds in fresh-cut tobacco were significantly higher than in the other tobacco types. The contents of nornicotine, neonicotine, anatabine, and total alkaloid showed a significant positive correlation with the total sensory evaluation score. The contents of nicotyrine and 2,3-bipyridine were significantly and negatively correlated with the total sensory evaluation score. A remarkable negative correlation was found between starch content and score on irritation. Furthermore, the amounts of neochlorogenic acid, chlorogenic acid, caffeic acid, and total polyphenols were significantly and positively correlated with the total sensory evaluation score. The amounts of aldehydes and phenolic compounds had a significant negative correlation, while the amount of olefin compounds had a significant positive correlation, with the total sensory evaluation score. These chemicals in tobacco leaves can be used as in analyses screening of other suitable tobacco types, and as reference standards for selecting tobacco raw materials suitable for high-quality heated tobaccos.

Comparison of vessel density in macular and peripapillary regions between primary open-angle glaucoma and pseudoexfoliation glaucoma using OCTA.

The aim of our study was to compare macular and peripapillary vessel density using optical coherence tomography angiography (OCTA) between eyes with primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG). Thirty-six POAG and 34 PXG eyes with similar visual field defect (no statistically significant difference between average mean deviation and pattern standard deviation scores) were included. Macular superficial vessel density (msVD) in the superficial macular layer and foveal avascular zone (FAZ) parameters were assessed with (6 × 6mm) and peripapillary vessel density (ppVD) in the radial peripapillary capillary (RPC) with (4.5 × 4.5mm) OCTA scans. Area under the receiver operating curve was used for assessing diagnostic capability. In PXG group, all msVD parameters had lesser values, and especially in parafoveal region, statistically significant decrease was shown (p = 0.008) in all subdivisions except nasal (p = 0.053). FAZ area was more larger in PXG [0.32(0.25-0.36)] than POAG [0.28(0.22-0.39)],(p = 0.944). FAZ density - 300 μm had statistically significant decrease in PXG (47.22 ± 6.92) according to POAG groups (50.63 ± 7.25) (p = 0.048). Most of RPC VD parameters had decreasing values in PXG group (p > 0.05). VDs and corresponding thicknesses had significant remarkable positive correlation in both macular and peripapillary regions. Significant remarkable negative correlations were observed between fovea VD and FAZ area, FAZ perimeter and between fovea thickness and FAZ area, FAZ perimeter. PXG eyes were found to have lesser values in terms of VD in the macular area, especially in the parafoveal and FD-300 regions, compared to POAG eyes which had similar functional and structural glaucomatous damage. Patients whose etiology was PXG and who seemed to have the same functional damage as those with POAG were actually found to have greater macular vascular damage. In addition, it was observed that macular vascular parameters correlated with peripapillary vascular parameters.

Diagnostic value of circulating microRNA‐19b in heart failure

For differentiating heart failure (HF) with preserved ejection fraction (HFpEF) from HF with reduced EF (HFrEF), N-terminal prohormone brain natriuretic peptide (NT-proBNP) is less accurate. Decreased expression of microRNA-19b (miR-19b) is associated with increased cardiac-fibrosis. We aim to evaluate the value of miR-19b in diagnosing HFrEF patients. We included 200 HF patients and 100 healthy controls. Intergroup comparisons of miR-19b were made and correlation between miR-19b and NT-proBNP was analysed. Diagnostic values of NT-proBNP and miR-19b for HF patients versus controls and HFrEF versus HFpEF were obtained by ROC analysis and described by area under curve (AUC), sensitivity and specificity. HFrEF patients (0.87, 95% CI 0.37-1.45) had significantly lower miR-19b level than HFpEF group (1.32, 95% CI 0.63-2.51) and the controls (1.82, 95% CI 0.37-1.45) (both P<.001). There was a remarkable negative correlation between miR-19b and NT-proBNP (P<.001). The additional use of miR-19b did not improve the accuracy of NT-proBNP alone in diagnosing HF patients from the controls (both AUC=0.98, 95%CI 0.97-0.99). However, as for distinguishing the HFpEF from HFrEF, miR-19b and NT-proBNP yielded a significantly higher AUC than NT-proBNP alone (0.85, 95% CI 0.80-0.90 vs. 0.66, 95% CI 0.58-0.74) (P<.001), and the sensitivity for diagnosing HFrEF was raised from 58% to 77% and the specificity from 75% to 79%. On top of NT-proBNP, miR-19b added the value in diagnosing HFrEF. But in view of satisfactory accuracy of NT-proBNP in predicting HF from the healthy volunteers, miR-19b did not provide incremental value.

Correlation of extracellular polymeric substances and microbial community structure in denitrification biofilm exposed to adverse conditions.

Microbial community may respond to different adverse conditions and result in the variation of extracellular polymeric substances (EPS) in denitrification biofilm; this study discovered the role of EPS in accordance with the analysis of cyclic diguanylate (c-di-GMP) and electron equilibrium (EE) under low organic loading rate, shock organic loading rate and low temperature conditions. Good nitrate removal performance could be achieved under shock organic loading rate and low temperature conditions; however, owing to the low organic loading rate, the carbon source was preferentially utilized for biomass growth. Tightly bound EPS (TB-EPS) contents progressively increased and facilitated cell adhesion and biofilm formation. The stable TB protein (TB-PN) content in TB-EPS built a cross-linked network to maintain internal biofilm structure and led to the rapid biosynthesis of polysaccharides, which could further enhance microbial adhesion and improve nitrate removal. C-di-GMP played an important role in biomass retention and biofilm formation, based on the correlation analysis of c-di-GMP and EPS. TB polysaccharide (TB-PS) contents presented a significant positive correlation with c-di-GMP content, microbial adhesion and biofilm stabilization was further enhanced through c-di-GMP regulation. In addition, a remarkable negative correlation between electron deletion rate (EDR) and TB-PN and TB-PS was discovered, and TB-PS was required to serve as energy source to enhance denitrification according to EE analysis. Surprisingly, dynamic microbial community was observed due to the drastic community succession under low temperature conditions, and the discrepancy between the dominant species for denitrification was found under shock organic loading rate and low temperature conditions. The notable increase in bacterial strains Simlicispira, Pseudomonas and Chryseobacterium was conducive to biofilm formation and denitrification under shock organic loading rate, while Dechloromonas and Zoogloea dramatically enriched for nitrate removal under low temperature conditions. The high abundance of Dechloromonas improved the secretion of EPS through the downstream signal transduction, and the c-di-GMP conserved in Pseudomonas concurrently facilitated to enhance exopolysaccharide production to shock organic loading rate and low temperature conditions.

The reduced left hippocampal volume related to the delayed P300 latency in amnestic mild cognitive impairment.

Amnestic mild cognitive impairment (aMCI) is characterized by delayed P300 latency and reduced grey matter (GM) volume, respectively. The relationship between the features in aMCI is unclear. This study was to investigate the relationship between the altered P300 latency and the GM volume in aMCI. Thirty-four aMCI and 34 well-matched normal controls (NC) were studied using electroencephalogram during a visual oddball task and scanned with MRI. Both tests were finished in the same day. As compared with the NC group, the aMCI group exhibited delayed P300 latency in parietal cortex and reduced GM volumes in bilateral temporal pole and left hippocampus/parahippocampal gyrus. A remarkable negative correlation was found between delayed P300 latency and reduced left hippocampal volume only in the aMCI group. Interestingly, the mediating analysis found P300 latency significantly mediated the association between right supramarginal gyrus volume and information processing speed indicated by Stroop Color and Word Test A scores. The association between delayed P300 latency and reduced left hippocampal volume in aMCI subjects suggests that reduced left hippocampal volume may be the potential structural basis of delayed P300 latency.

Study on Surface Rainwater and Arc Characteristics of High-Voltage Bushing With Booster Sheds Under Heavy Rainfall

The flashover performance of insulators can be improved by BS (booster sheds) in the rain, which is mainly attributed to the reasons that BS break up long cascades of water and block connections of arcs. However, surface rainwater characteristics and arc characteristics of bushing have not been quantitatively studied under heavy rainfall. In this article, the artificial rain tests were conducted on a 500 kV transformer high-voltage bushing equipped with and without BS under the rainfall intensity of 10 mm/min. X (the total length of water column) and L arc (the critical length of arc) on the bushing surface were taken as the feature parameters of surface rainwater characteristics and arc characteristics, respectively. The effects of BS on E h (the rain flashover voltage gradient along the insulation height), X and L arc were investigated, respectively. Furtherly, the relationships were studied among Eh, X and L arc . Results indicate that E h has a sharp rise as the number of BS (NBS) is from one to two, however the rise of E h gradually decreases when NBS exceeds two. X decreases while L arc increases with the rise of NBS, however both the change ranges of them continually fall. Furthermore, L arc presents remarkable negative correlation to X because of the effect of the electric field. E h rises nonlinearly with the decrease of X, which is due to the change of the wetting uniformity on the bushing surface and the potential redistribution along air gaps in the presence of the local arc.

Variations and influence factors of 210Pb-specific radioactivity in modern calcite depositions in a subtropical cave, South China

Although 210Pb dating has been successfully used in speleothems, the understanding of the factors impacting 210Pb variations in modern calcite depositions in karst caves is poor due to the lack of in situ monitoring. Here, we studied the 210Pb variations in drip water and modern calcite depositions at five sampling sites in Maomaotou Big Cave in Guilin, south China, through more than three years of in situ monitoring. In this work, the air 222Rn concentrations, weights and 210Pb-specific radioactivity of modern calcite depositions showed significant temporal and spatial variations. The modern calcite deposition weights and 222Rn concentrations in the air of Maomaotou Big Cave ranged from 0.02 to 6.04 g and 62.9–628 Bq.m−3 (higher values in summer-autumn and lower values in winter–spring), respectively, while the 210Pb-specific radioactivities in calcite depositions varied from 7.33 to 658.52 Bq•kg−1, with lower values reported in summer–autumn and higher values in winter–spring. The opposite seasonal trends observed for the 222Rn concentrations and 210Pb-specific radioactivity indicated that the air 222Rn concentration was not the dominant factor influencing the 210Pb-specific radioactivity in the modern calcite depositions. This study concluded that 210Pb-specific radioactivity in modern calcite depositions is mainly carried by drip water; further, the remarkable negative correlation between deposition weight and 210Pb-specific radioactivity in modern calcite depositions suggests that the Constant Initial Concentration model (CIC) is fit for recent speleothem dating in a closed system. Such important information may provide a scientific basis for cave deposition dating using 210Pb.

Preparation of heat-resistant poly(amide-imide) films with ultralow coefficients of thermal expansion for optoelectronic application

The novel poly(amide imide) (PAI) films derived from three kinds of amide-containing diamines and different aromatic dianhydrides were synthesized and characterized. These PAI films exhibited excellent mechanical and thermal properties due to the rigidity of main chains and existence of strong hydrogen bonding interactions. For PAI films based on the diamine N,N′-(1,4-phenylene)bis(4-aminobenzamide) (PABA), their tensile strength and modulus even exceeded 280 MPa and 10 GPa, accompanied with Tg and T5 values higher than 408 °C and 520 °C, respectively. The results indicated that CTE values of these PAI films were greatly affected by rigidity, orientation and packing of chains as well as hydrogen bonding interactions. PABA-based PAI films with the highest amide content and linearly rigid backbones had ultralow in-plane CTE values ranging from −4.6 to −0.8 ppm/°C in the temperature range of 30–300 °C combined with the largest ∆n values of 0.22–0.23, suggesting a remarkable negative correlation between CTE and ∆n. The hydrogen bonding interactions were proved to be maintained at high temperature, and it was crucial for the regulation and control of thermal expansion. These heat-resistant PAI films with high tensile strength and ultralow CTE can be used as flexible polymeric substrates for optoelectronic application.

Prefrontal-Temporal Pathway Mediates the Cross-Modal and Cognitive Reorganization in Sensorineural Hearing Loss With or Without Tinnitus: A Multimodal MRI Study.

Objective: Hearing loss, one main risk factor of tinnitus and hyperacusis, is believed to involve significant central functional abnormalities. The recruitment of the auditory cortex in non-auditory sensory and higher-order cognitive processing has been demonstrated in the hearing-deprived brain. The dorsolateral prefrontal cortex (dlPFC), which has dense anatomical connections with the auditory pathway, is known to play a crucial role in multi-sensory integration, auditory regulation, and cognitive processing. This study aimed to verify the role of the dlPFC in the cross-modal reorganization and cognitive participation of the auditory cortex in long-term sensorineural hearing loss (SNHL) by combining functional and structural measurements.Methods: Thirty five patients with long-term bilateral SNHL and 35 matched healthy controls underwent structural imaging, resting-state functional magnetic resonance imaging (rs-fMRI), diffusion tensor imaging (DTI), and neuropsychological assessments. Ten SNHL patients were with subjective tinnitus.Results: No differences in gray matter volume, spontaneous neural activity, or diffusion characteristics in the dlPFC were found between the SNHL and control groups. The functional connectivity (FC) between the dlPFC and the auditory cortex and visual areas, such as the cuneus, fusiform, lingual cortex, and calcarine sulcus was increased in patients with SNHL. ANOVA and post hoc tests revealed similar FC alterations in the SNHL patients with and without tinnitus when compared with the normal hearing controls, and SNHL patients with and without tinnitus showed no difference in the dlPFC FC. The FC in the auditory cortex was associated with the symbol digit modality test (SDMT) scores in the SNHL patients, which reflect attentional function, processing speed, and visual working memory. Hearing-related FC with the dlPFC was found in the lingual cortex. A tract-based spatial statistics (TBSS) analysis revealed decreased fractional anisotropy (FA) values, mainly in the temporal inferior fronto-occipital fasciculus (IFOF), which showed remarkable negative correlations with the mean hearing thresholds in SNHL.Conclusion: Higher functional coupling between the dlPFC and auditory and visual areas, accompanied by decreased FA along the IFOF connecting the frontal cortex and the occipito-temporal area, might mediate cross-modal plasticity via top-down regulation and facilitate the involvement of the auditory cortex in higher-order cognitive processing following long-term SNHL.

Damage Evolution of Sandy Mudstone Mechanical Properties Under Mining Unloading Conditions in Gob-Side Entry Retaining

Based on stress evolution induced by mining activity, triaxial confining pressure unloading tests with multiple failure state under multi-level axial stress were conducted on sandy mudstone, which were from the roof above roadside backfill area in gob-side entry retaining. Stress–strain curves and damage evolution curves of rock specimens were analyzed as well as the mechanical properties during different confining pressure unloading stages. The results show that sandy mudstone suffers mechanical properties damage and dilatancy deformation along the unloading direction during the confining pressure unloading tests under both first level axial stress and second level axial stress. Both of the corresponding axial strain of the first failure state and that of the second failure state increase with the increase of confining pressure, and the corresponding circumferential strain and volume strain increase with the decrease of confining pressure. In particular, the confining pressure unloading factor of rock specimen was introduced to describe the damage evolution characteristics of mechanical properties. There is remarkable negative linear correlation between deformation modulus, cohesion, and friction angle and confining pressure unloading factor, whereas positive linear correlation between dilatancy angle and confining pressure unloading factor is obtained. Meanwhile, shear failure characteristics were observed in triaxial confining pressure unloading tests with multiple failure state under multi-level axial stress.