Partial Correlation Analysis Research Articles

Gender and Age Differences in Corpus Callosum Morphology: High-Altitude Adaptations in Native Tibetan Populations.

The corpus callosum is recognized as the largest interhemispheric white matter structure, coordinating distinct functions of the brain. High-altitude environments may influence the structure of the corpus callosum. This study aims to evaluate the morphologic characteristics of the corpus callosum in Tibetans residing on the Qinghai-Tibet Plateau while investigating the effects of sex, age, and high-altitude exposure on its morphology. The study comprised 262 healthy native Tibetan adults, including 113 men and 149 women. The length, height, area, and thickness of each subregion of the corpus callosum were measured, with the data normalized according to brain length and mid-sagittal cortical brain area. Statistical analyses were conducted utilizing nonparametric tests and partial correlation analysis. Most normalized morphologic measurements indicated significant sex differences, particularly in the thickness of the rostrum (z=-3.199, P=0.001), genu (z=-3.133, P=0.002), body (z=-3.612, P<0.001), splenium (z=-2.279, P=0.02), and callosal length (z=-2.722, P=0.006), and area (z=-2.179, P=0.03). The callosal area (R2=0.084, P<0.001) demonstrated an inverted U-shaped trajectory throughout the lifespan, peaking at ∼40 years of age. This study identified pronounced sex differences in the corpus callosum morphology among Tibetans. Despite living at high altitudes, the age-related trajectory of the callosal area resembled patterns observed in other populations, although peak ages differed by sex.

Application of a Modified Ecological Quality Monitoring Method in the Southeastern Hilly Region of China

The southeastern hilly region of China is ecologically significant but highly vulnerable to climate change and human activities. This study developed a Modified Remote Sensing Ecological Index (MRSEI) using satellite imagery and Human Footprint data to assess ecological quality across 14 cities surrounding the Wuyi Mountains. We applied Sen’s slope analysis, the Mann–Kendall test, and spatial autocorrelation to evaluate spatiotemporal ecological changes from 2000 to 2020, and used partial correlation analysis to explore the drivers of these changes. The main findings are as follows: (1) Ecological quality generally improved over the study period, with significant year-to-year fluctuations. The eastern region, characterized by higher altitudes, consistently exhibited better ecological quality than the western region. The area of low-quality ecological zones significantly decreased, while Ji’an, Ganzhou, Heyuan, and Meizhou saw the most notable improvements. In contrast, urban areas experienced a marked decline in ecological quality. (2) The region is undergoing warming and wetting trends. Increased precipitation, especially in the western and northern regions, improved ecological quality, except in urban areas, where it heightened flood risks. Rising temperatures had mixed effects: they enhanced ecological quality in high-altitude areas (~516 m) but negatively impacted low-altitude regions (~262 m) due to intensified heat stress. (3) Although industrial restructuring reduced environmental pressure, rapid population growth and urban expansion created new ecological challenges. This study provides an innovative method for the ecological monitoring of hilly regions, effectively integrating human activity and climatic factors into ecological assessments. The findings offer valuable insights for sustainable development and ecological management in similar sensitive regions.

Spatiotemporal Evolution of Air–Sea CO2 Flux in the South China Sea and Its Response to Environmental Factors

Increasing atmospheric carbon dioxide (CO2) from human activities underscores the need to understand air–sea CO2 flux in marine environments, particularly in marginal seas like the South China Sea (SCS). This research analyzes the spatial and temporal patterns of air–sea CO2 flux across four typical regions of the SCS: the northern SCS, western SCS, SCS basin, and northeastern SCS. Our results show that the SCS serves as a carbon source from spring to autumn and shifts to a carbon sink in winter. The northern SCS exhibits strong carbon sink behavior during winter, transitioning to a source in warmer months, while the western SCS and SCS basin consistently act as carbon sources year-round, with summer peaks. The northeastern SCS acts as a source in warmer months, becoming a weak sink in winter. Partial correlation analysis reveals that temperature and wind speed significantly influence air–sea CO2 flux, though regional differences exist. Notably, chlorophyll-a in the northern SCS is negatively correlated with air–sea CO2 flux, indicating that high primary productivity enhances CO2 absorption, whereas other regions show contrasting relationships. These findings provide valuable insights into the complex carbon cycle mechanisms in the SCS.

Psychometric validation of the Cardiac Distress Inventory - Short Form among people with cardiac diseases in Hong Kong

ObjectivesCardiac patients experience various somatic and psychosocial symptoms and stress is an important prognostic factor of cardiac rehabilitation. This study evaluated the psychometric properties of the 12-item Cardiac Distress Inventory – Short Form (CDI-SF) in the Chinese context.MethodsA total of 227 patients with cardiac diseases were recruited in a specialist outpatient clinic in Hong Kong between Aug 2022 and July 2023. The participants completed the CDI-SF and validated measures on psychosocial functioning and quality of life. Exploratory factor analysis and partial correlation analysis were conducted to examine the factorial validity, reliability, and convergent validity of the CDI-SF with reference to validating measures.ResultsThe 1-factor model showed adequate model fit with excellent composite reliability (ω = .92) and substantial factor loadings (λ = .64 –.94, p &amp;lt;.01). The CDI-SF factor was negatively associated with age (r = –.21, p &amp;lt;.01) and showed positive and strong partial correlations (r = .59 –.69, p &amp;lt;.01) with impact of event, depression, and burnout, and negative partial correlations (r = -.43 to -.54, p &amp;lt;.01) with resilience and quality of life.ConclusionOur study provides the first results on the psychometric properties of the CDI-SF among cardiac patients in Hong Kong. The psychometric results support the CDI-SF as a precise, valid, and reliable measure of cardiac distress in the Chinese context.

Are We Missing Obstructive Sleep Apnea in Patients With Non-traumatic Subglottic Stenosis?

To investigate the association between subglottic stenosis (SGS) and obstructive sleep apnea (OSA). This is a cross-sectional pilot cohort study conducted at a single tertiary academic center from 2022 to 2023. Subjects with non-traumatic SGS were recruited for enrollment. All subjects completed a peak expiratory flow (PEF) measurement, validated sleep questionnaires: Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI), and a 1-night home sleep test (HST). Demographic data were summarized. Prevalence was calculated and descriptively compared to a matched population. Partial correlation analysis evaluated the relationship of PEF% and Meyer-Cotton grading, in addition to PEF% and apnea-hypopnea index (AHI). Sleep quality was compared in subjects with and without OSA via a Mann-Whitney U test. Twenty subjects participated; all were Caucasian females with a mean age of 48.4 (10.4) years and a body mass index (BMI) of 24.1 (3.8). The majority (80%) had idiopathic SGS, and a mean PEF 288 (71) L/min. OSA was present in 40% of subjects, of which 15% had moderate OSA. PEF% did not correlate to AHI (P > .05). Poor sleep quality (PSQI ≥ 5) was present in 70% of subjects and 20% had excessive daytime sleepiness (ESS > 9). PSQI and ESS did not differ between subjects with and without OSA (P > .05). OSA prevalence is elevated in a cohort of subjects with SGS. Further study of airway dilation's impact on OSA is necessary. Screening and surveillance for OSA in patients with subglottic stenosis may need to be considered based on this study's findings.Level of Evidence: Level 3.

Spatio-temporal Variation in Monthly Vegetation NPP and Its Responses to Climate and Terrain Factors in Chang-Zhu-Tan Green Heart Area

The Chang-Zhu-Tan ecological Green Heart area is the largest urban agglomeration Green Heart area in China. To clarify the spatiotemporal changes and driving factors of net primary productivity （NPP） of vegetation in the Chang-Zhu-Tan Green Heart area, an improved Carnegie Ames Stanford Approach （CASA） model was used to estimate the monthly vegetation NPP from 2011 to 2020 based on measured and remote sensing data. With the help of ArcGIS 10.2 software, linear regression and spatial partial correlation analysis were used to explore the spatiotemporal variations in monthly vegetation NPP and its responses to climate and terrain factors. The results showed that the monthly vegetation NPP in the Chang-Zhu-Tan Green Heart area showed an overall trend of first increasing and then decreasing, with an average vegetation NPP growth rate （measured in C, the same below） of 5.75 g·（m2·month）-1 from January to July and a monthly decrease rate of 2.64 g·（m2·month）-1 from August to December. The spatial distribution of monthly vegetation NPP in the Green Heart area showed a significant difference, with a coefficient of variation ranging from 34.52% to 48.76%. The high values of vegetation NPP in each month were concentrated in the ecological core areas of the central and eastern parts in the Green Heart area, whereas the low values were mainly distributed along the Xiangjiang River in the western part and in the narrow and elongated areas in the southern part of the Green Heart Area. The impact of climate and terrain factors on the monthly NPP of vegetation in the Green Heart area had both positive and negative inhibitory effects. Among climate factors, solar radiation was the major controlling factor for monthly vegetation NPP changes. The impact of terrain factors on vegetation NPP was relatively weak, with slope orientation having a greater positive impact on vegetation NPP than altitude and slope.

Analysis of Spatiotemporal Variation Characteristics and Influencing Factors of Grassland Vegetation Coverage in the Qinghai–Tibet Plateau from 2000 to 2023 Based on MODIS Data

Changes in grassland fractional vegetation coverage (FVC) are important indicators of global climate change. Due to the unique characteristics of the Tibetan Plateau ecosystem, variations in grassland coverage are crucial to its ecological stability. This study utilizes the Google Earth Engine (GEE) platform to retrieve long-term MODIS data and analyzes the spatiotemporal distribution of grassland FVC across the Qinghai–Tibet Plateau (QTP) over 24 years (2000–2023). The grassland growth index (GI) is used to evaluate the annual grassland growth at the pixel level. GI is an important indicator for measuring grassland growth status, which can effectively measure the changes in grassland growth in each year relative to the base year. FVC trends are monitored using Sen-Mann-Kendall slope estimation, the coefficient of variation, and the Hurst exponent. Geographic detectors and partial correlation analysis are then applied to explore the contribution rates of key driving factors to FVC. The results show: (1) From 2000 to 2023, FVC exhibited an overall upward trend, with an annual growth rate of 0.0881%. The distribution of FVC on the QTP follows a pattern of higher values in the east and lower values in the west; (2) Over the past 24 years, 54.05% of the total grassland area has shown a significant increase, 23.88% has remained stable, and only a small portion has shown a significant decrease. The overall trend is expected to continue with minimal variability, covering 82.36% of the total grassland area. The overall grassland GI suggests a balanced state of growth; (3) precipitation (Pre) and soil moisture (SM) are the main single factors affecting FVC changes in grasslands on the Tibetan Plateau (q = 0.59 and 0.46). In the interaction detection, in addition to the highest interaction between Pre and other factors, the interaction between SM and other factors also showed a significant impact on the changes in FVC of the QTP grassland; partial correlation analysis of hydrothermal factors and FVC of the QTP grassland. It shows that precipitation has a stronger correlation with QTP grassland FVC changes than temperature. This study has enhanced our understanding of grassland vegetation change and its driving factors on the QTP and quantitatively described the relationship between vegetation change and driving factors, which is of great significance for maintaining the sustainable development of grassland ecosystems.

Altered brain regional homogeneity, depressive symptoms, and cognitive impairments in medication-free female patients with current depressive episodes in bipolar disorder and major depressive disorder

BackgroundAlthough symptoms of depressive episodes in patients with bipolar depressive episodes (BDE) and major depressive disorder (MDD) are similar, the treatment strategies for these disorders are completely different, suggesting that BDE and MDD have different neurobiological backgrounds. In this study, we examined the relationship between brain function and clinical symptoms, particularly cognitive function, in female individuals with bipolar disorder and MDD experiencing depressive episodes.MethodsRegional homogeneity (ReHo) was analyzed in 51 medication-free female patients with BDE, 63 medication-free female patients with MDD, and 45 female healthy controls (HCs). Depressive symptom severity was assessed using the 24-item Hamilton Depression Rating Scale (HAMD-24), and multidimensional cognitive function was evaluated using the MATRICS Consensus Cognition Battery. Partial correlation analysis was used to explore the links between the brain regions and clinical characteristics. A support vector machine (SVM) was used to assess the classification accuracy.ResultsCompared with HCs, patients with BDE and MDD had decreased ReHo in the left lobule VI of the cerebellum and increased ReHo in the left precuneus. Patients with BDE also had reduced ReHo in the left lobules IV–V of the cerebellum and increased ReHo in the right putamen, unlike patients with MDD who had no significant differences in these regions. Patients with BDE exhibited more severe cognitive deficits in processing speed, attention, word learning, and overall cognitive function than those with MDD. In patients with BDE, a significant negative correlation was found between the right putamen and HAMD-24 scores. However, no significant association was observed between abnormal ReHo levels and cognitive function. The SVM effectively differentiated between patients with BDE, MDD, and HCs.ConclusionCognitive impairment was more severe in female patients with BDE than in those with MDD. Changes in the ReHo values of the right putamen and left lobules IV–V may serve as unique neuroimaging markers for BDE. Alterations in the ReHo values of the left precuneus and left lobule VI could serve as common pathophysiological mechanisms for BDE and MDD in women and indicate depressive states.

Muscle-Fiber Typology Is Associated With Sprint-Cycling Characteristics in World-Class and Elite Track Cyclists.

Identifying the determinants of performance is fundamental to talent identification and individualizing training prescription. Consequently, the aim of this study was to determine whether estimated muscle typology is associated with the key mechanical characteristics of track sprint cycling. Sixteen world-class and elite track cyclists (n = 7 female) completed a laboratory session wherein torque-cadence and power-cadence profiles were constructed to determine maximal power output (Pmax), optimal cadence (Fopt), and maximal cadence (Fmax), and fatigue rate per pedal stroke was determined during a 15-second maximal sprint at Fopt. Muscle typology was estimated by measuring carnosine content via proton magnetic resonance spectroscopy in the gastrocnemius and soleus. Using partial correlation analysis to account for sex, greater muscle carnosine content (ie,greater estimated proportion of type II fibers) was associated with a greater Pmax (r = .68, P = .007), Fmax (r = .77, P = .0014), Fopt (r = .61, P = .0196), and absolute fatigue rate (W·stroke-1; r = -.55, P = .0418) but not relative fatigue rate (%peak power·stroke-1; r = -.33, P = .246). The findings from this study substantiate the mechanical differences in muscle-fiber types derived from single muscle-fiber studies and highlight the importance of estimated muscle typology for sprint cycling performance.

Bio-filtration of Organic Pollutants: Simulation and Mathematical Modelling of Toluene and n-propanol

AbstractVolatile organic compounds (VOCs) are chemical substances that evaporate quickly, releasing harmful fumes into the atmosphere. Among the various VOCs, toluene and n-propanol are particularly interesting due to their widespread occurrence and considerable industrial impact. This study uses a bio-reactor with microbial biofilm formation to present the bio-degradation of a composition of toluene (methylbenzol) and n-propanol (1-propanol). It predicts the coupled inhibition effect of n-propanol on the toluene removal efficiency. The bio-filtration process is modelled as a dynamical system using a set of deterministic nonlinear partial differential equations. The differential equation with its appropriate conditions describes the bio-filtration processes occurring in two distinct phases: the biofilm phase and the gaseous phase. The differential equation is solved using the Chebyshev pseudospectral method and the local linearization method to understand the physical dynamics of the mathematical model. The effectiveness of the spectral-based method was evaluated by comparing its accuracy to known results in the limiting cases of the current dynamical model. A parametric and partial rank correlation coefficient (PRCC) analysis of the dimensionless parameters is conducted. It was found that toluene removal is enhanced by the additional desorption rate constant, ζ2. Increasing the air-biofilm coefficient for n-propanol supports the removal of n-propanol but not that of toluene. The findings of this study contribute to improvements in bio-degradation modelling and enhance our understanding of volatile organic compounds.

7-Tesla magnetic resonance imaging for monitoring microstructural changes in the lenticulostriate artery-neural complex in patients with hypertension.

The lenticulostriate artery-neural complex (LNC), which includes the lenticulostriate artery (LSA) and surrounding neural structure, is a new concept proposed by neurologists and plays a pivotal role in hypertension-induced stroke. Conventional low-magnitude magnetic resonance imaging (MRI) has not been successfully used to reveal the microstructural changes of the LNC. This study aimed to evaluate the microstructural changes of the LNC in patients with prestroke hypertension using 7-Tesla (7-T) MRI and to identify the potential MRI biomarkers for monitoring hypertension-related neurological disorders. This prospective, cross-sectional study was conducted in Chongqing, China, from February 2023 to January 2024. Its protocol complied with the Declaration of Helsinki (revised in 2013) and was approved by the Medical Science Research Ethics Committee of Southwest Hospital, Third Military Medical University, and all participants provided written informed consent. Patients with hypertension (N=32) and age-matched healthy volunteers (N=30) were enrolled. All participants underwent 7-T MRI. The number, length, and tortuosity of the LSA were measured, as were the volumes of the basal ganglia, internal capsule, and thalamus. The relationship between the LSA features and the neural structure volumes was also analyzed through partial correlation analysis. The stem, lengths of the LSA, and volume of nerve structure in LNC showed significant differences between the two groups (P<0.05). In the right hemisphere, the stem number of LSA was higher than that in the healthy group (P<0.05). Furthermore, the volumes of the globus pallidus, putamen, thalamus, caudate nucleus, and internal capsule were found to be significantly larger in healthy participants than in patients with hypertension (P<0.05). The tortuosity of the LSA was positively correlated with the internal capsule volume in the left hemisphere (r=0.460; P<0.001) and the globus pallidus (r=0.517; P<0.001). For the right hemisphere, there was a positive correlation between the stems number in the LSA and the volume of the internal capsules (r=0.340; P=0.007) and the globus pallidus (r=0.299; P=0.018). The tortuosity of the LSA was positively correlated with the volume of the internal capsule (r=0.504; P<0.001) and globus pallidus (r=0.431; P<0.001). Meanwhile, we found the number of LSA branches entering the putamen was higher in healthy individuals than in patients with hypertension (P<0.01). Using 7-T MRI, we obtained ultrahigh-resolution images of the LNC and found that the microstructures of LNC were changed in the prestroke patients with hypertension. MRI monitoring of microstructural changes in LNC, including the number of LSA stems and the internal capsule and globus pallidus volume, may serve as predictive biomarkers for intracranial changes and potential complications caused by hypertension.

Altered Density of Resting-State Long- and Short-Range Functional Connectivity in Patients with Moderate-to-Severe Obstructive Sleep Apnea.

This study is to evaluate the altered number of functional connection (s) in patients with obstructive sleep apnea (OSA) by functional connectivity density (FCD), to investigate its relationship with cognitive function, and to explore whether these features could be used to distinguish OSA from healthy controls (HCs). Seventy-six OSA patients and 72HCs were included in the analysis. All participants underwent resting-state functional magnetic resonance imaging scan. Subsequently, intergroup differences between long-and short-range FCD groups were obtained in the Matlab platform by using the degree centrality option with a 75 mm cutoff. The partial correlation analysis were used to assess the relationship between the altered FCD value and clinical assessments in OSA patients. The FCD values of the different brain regions were used as classification features to distinguish the two groups by support vector machine (SVM). Compared to HCs, OSA patients had decreased long-range FCD in the right superior frontal gyrus (SFG), right precuneus, and left middle frontal gyrus (MFG). Simultaneously, increased long-range FCD in the right cingulate gyrus (CG). Meanwhile, the short-range FCD were decreased in the right postcentral gyrus (PoCG), right SFG, left MFG, and right CG. The short-range FCD values of the right PoCG were correlated with the Montreal Cognitive Assessment scores in OSA patients. SVM analysis showed that FCD in differential brain regions could differentiate OSA patients from HCs. Long- and short-range FCD values in different brain regions of OSA patients may be related to cognitive decline, and also be effective in distinguishing OSA patients from HCs. These findings provide new perspectives on neurocognition in OSA patients.

Differences in the regulation of soil carbon pool quality and stability by leaf-litter and root-litter decomposition

Litter plays a crucial role in soil ecosystems. However, the differences in decomposition between leaf-litter and root-litter and their relative contributions to soil carbon pools and stability are not yet clear. Therefore, we conducted a 450-day in situ decomposition experiment in a semi-arid grassland to investigate the effects of soil biophysical and chemical properties on litter decomposition and to elucidate the dynamics of soil carbon pools during the decomposition process. The results showed that the decomposition rate (K) of leaf-litter was significantly higher than that of root-litter, and litter quality was the most important factor affecting the K of leaf-litter (58%) and root-litter (63%). Leaf-litter decomposition was more effective in promoting the increase in soil leucine aminopeptidase and β-1,4-glucosidase activities, as well as the accumulation of microbial biomass carbon (MBC), particulate organic carbon (POC), and dissolved organic carbon (DOC), compared to root-litter. However, the difference in the impact of leaf-litter and root-litter on soil organic carbon (SOC) was not significant. The decomposition of leaf-litter contributed more significantly to enhancing the soil carbon pool management index (CPMI) compared to root-litter, with increases of 39% and 25%, respectively. In contrast, leaf-litter decomposition significantly reduced the mineral-associated organic carbon (MAOC) and the MAOC/POC ratio, while root-litter decomposition significantly increased the MAOC and MAOC/POC. Random forest, partial correlation, and path analysis indicated that the effects of leaf-litter and root-litter decomposition on CPMI were mainly regulated by decomposition time and soil carbon components, while the effects on MAOC/POC were mainly controlled by litter quality. The results demonstrate that both leaf-litter and root-litter can enhance soil carbon storage and CPMI, but root-litter may be more beneficial for soil carbon pool stability. These results further contribute to the understanding of the continuous system of litter-soil carbon pools.

Empowering Nursing Practices: Enhancing Patient Care Through Knowledge, Attitude and Practice Towards Urinary Catheterisation in Taicang City.

To assess the knowledge, attitude and practice (KAP) towards unnecessary urinary catheterisation among nurses in Taicang City, China. Cross-sectional study. This study included nurses from our hospital and was conducted between February 2023 and June 2023. A self-administered questionnaire was designed to collect their demographic characteristics and KAP. A total of 233 valid questionnaires were collected. The mean KAP scores were 13.44 ± 1.62 (possible range: 0-17), 45.28 ± 3.87 (possible range: 10-50) and 43.85 ± 5.98 (possible range: 10-50), which indicated moderate knowledge, positive attitude and proactive practice, respectively. The Pearson's correlation analysis showed positive correlations between knowledge and attitude (r = 0.253, p < 0.001), knowledge and practice (r = 0.279, p < 0.001), as well as attitude and practice (r = 0.441, p < 0.001). Partial correlation analysis adjusted for age, gender, department, working experience and experience in treating patients with catheter-associated urinary tract infections also showed positive correlations among KAP. A structural equation modelling showed that both knowledge (β = 0.501, p = 0.047) and attitude (β = 0.691, p < 0.001) had direct effect on practice. This study found moderate knowledge, positive attitude and proactive practice among the participants. Both knowledge and attitude might affect their practice. We wanted to know the knowledge, attitude and behaviour of nurses in Taicang City towards unnecessary catheterisation. Moderate knowledge, positive attitude and proactive practice were found among the participants. The findings would provide evidence for policymakers to develop targeted educational intervention to improve nurses' practice and might improve the outcomes of patients. This study was reported to be adhered to the STROBE guideline. No patient or public contribution. Targeted educational intervention was needed to improve nurses' practice.

Detection of spatiotemporal changes in eco-environmental quality based on RSEI and SG filtering and its driving force analysis: a case study in Sichuan Province, China.

Landsat images were extracted using Google Earth Engine (GEE) platform and optimized by Savitzky-Golay (SG) filtering. The Remote Sensing Ecological Index (RSEI) method was used to analyze the eco-environmental quality in Sichuan Province in recent 20years. In addition, Theil-Sen median method and Mann-Kendall (MK) test were used to test the change trend of eco-environmental quality. Furthermore, drivers were evaluated by partial correlation analysis, 2D scatter plots, and t tests. The results showed that (1) in the past 20years, the eco-environmental quality of Sichuan Province was on the rise, and the eco-environmental quality in the western region was better than that in the eastern region. The eco-environmental quality was positively correlated with forest and grassland types, and negatively correlated with cultivated land and urban and rural construction land types. (2) The eco-environmental quality of Sichuan Province is linearly correlated with the digital elevation model, but poorly correlated with slope and slope direction. In the range of slope 0° ~ 9° and southeast direction, the eco-environmental quality is the worst. (3) The eco-environmental quality of Sichuan Province was most significantly affected by soil moisture and sunshine hours. The study can help us to understand and assess the health of ecosystems in Sichuan Province, provide a scientific basis for protecting and improving the environment, and guide the formulation and implementation of environmental protection policies.

Decreased Water Diffusivity Along the Perivascular Space in Older Adults With Poor Sleep Quality.

This study included 52 Japanese older adults with Pittsburgh Sleep Quality Index (PSQI) scores > 5 and 52 healthy controls (HCs) with PSQI score ≤ 5. Diffusion-weighted imaging (DWI) and 3D T1-weighted imaging were acquired using 3T magnetic resonance imaging. The diffusion tensor image analysis along the perivascular space (DTI-ALPS) index was calculated using preprocessed DWI. The choroid plexus volume (CPV) was calculated using FreeSurfer 6.0. The mean ALPS index and CPV were compared between the older adults with poor sleep quality (PSQ) and HCs using a general linear model, adjusted for covariates including age, sex, years of education, total intracranial volume, systolic blood pressure, hemoglobin A1c, and white matter lesion volume. We also conducted a partial correlation analysis between the mean ALPS index and CPV, Montreal Cognitive Assessment (MoCA), and PSQI scores, adjusting for all the mentioned covariates. The PSQ group had a significantly lower mean ALPS index than HCs. The mean ALPS index in the PSQ group was negatively correlated with CPV and positively correlated with the MoCA score. Therefore, older adults with PSQ may experience dysfunction in the excretory pathway of the perivascular space around the medullary veins. This impairment may be associated with an increase in CPV and cognitive dysfunction.

The Dynamic Characteristics and Influencing Factors of Soil Respiration in Different Types of Grasslands in the Barkol Lake Basin

Determining regional and global carbon cycles hinges on investigating the dynamic characteristics and influencing factors of soil respiration in various types of natural grasslands located in arid regions, and these characteristics are important indicators for assessing the structural and functional health of grassland ecosystems. Such investigations also provide theoretical support for carbon sink monitoring, energy conservation, emission reduction and low-carbon development in the western arid zone and are important for obtaining an in-depth understanding of the carbon cycle, as well as for ecosystem management, restoration and the reconstruction of arid areas. In this study, during the growing season (from May to October) of 2022, the LI-8100A automated soil CO2 flux system was used to measure the soil respiration rate (Rs), temperature from 1.5 m above the surface to depths of 5–25 cm (T, T5, T10, T15, T20 and T25) and the soil moisture content (SM) at a depth of 20 cm in four types of grasslands: lowland meadow, alpine meadow, temperate desert steppe and temperate steppe desert. Five replicates were established for each plot, and the responses of Rs to T and SM were fitted to construct the optimal regression model. The results revealed that (1) the daily average soil respiration was highest in the lowland meadow (0.07 to 5.76 μmol·m−2·s−1), followed by the alpine meadow (−0.57 to 0.95 μmol·m−2·s−1), the temperate desert steppe (−0.45 to 3.0 μmol·m−2·s−1) and the temperate steppe desert (−1.29 to 1.61 μmol·m−2·s−1); (2) the soil respiration rates of the four grassland types were significantly correlated with the temperature in the 5–15 cm soil layer, and the best model was an exponential function; the peak values generally appeared between 13:00 and 17:00 (h), with the minimum values at 2:00 or 8:00 (h); the maximum value was observed in July–August, and the minimum value was observed in October; and the soil respiration in the lowland meadow was higher than that in the other three types of grassland during the same period. The average variation intensities of the soil respiration from May to October were as follows: temperate steppe desert (91.78%) &gt; temperate desert steppe (76%) &gt; alpine meadow (58.77%) &gt; lowland meadow (43.93%). (3) The partial correlation analysis revealed that when soil temperature was used as a control, the correlation between SM and soil respiration in the four types of grasslands changed, and the coefficient of determination (R2) increased to varying degrees, explaining up to 80% of the variation in the soil respiration in the lowland meadows. The correlation between soil respiration and the SM normalized to 10 °C explained up to 93.8% of the variation in soil respiration; the two-factor fitting equations revealed that the model with soil temperature and SM was superior to the single-factor model with either soil temperature or SM.

Systemic immune-inflammatory index predicts fragility fracture risk in postmenopausal anemic females with type 2 diabetes mellitus: evidence from a longitudinal cohort study

BackgroundChronic low-grade inflammation is related to bone metabolism in patients with type 2 diabetes mellitus (T2DM). However, credible data indicating the relationship between inflammation and fragility fracture risk in postmenopausal anemic females with T2DM are sparse. The current study sought to investigate the relationships between the systemic immune-inflammatory index (SII) and fragility fracture events, as well as the future 10-year fragility fracture probability evaluated using the fracture risk assessment tool (FRAX) in postmenopausal females with T2DM.MethodsAccording to the tertiles of SII, 423 postmenopausal females with T2DM were divided into three groups: low-level (≤ 381.32, n = 141), moderate-level (381.32–629.46, n = 141), and high-level (≥ 629.46, n = 141). All participants were followed up for 7 years with a median of 46.8 months (1651 person-years). The association between SII and fragility fracture risk was assessed.ResultsOf 423 subjects, 75 experienced a fragility fracture event. Spearman partial correlation analysis revealed that SII was negatively related to bone mineral density (BMD) and was positively associated with the future 10-year probability of major osteoporotic fracture (MOF) and hip fracture (HF). Restricted cubic spline (RCS) analysis revealed a positive correlation between SII and fragility fracture risk in an approximately inverted J-shaped dose–response pattern (P for overall < 0.0001). Multivariate Cox regression analysis demonstrated that patients with a high SII presented a greater risk of fragility fractures (P = 0.011). Stratified analysis revealed that fragility fractures in the high-level SII were predominantly associated with anemia with an increase of 4.15 times (P = 0.01). Kaplan‒Meier analysis indicated a greater cumulative incidence of fragility fractures in patients with a high SII (log-rank, all P = 0.0012). Receiver operating characteristic (ROC) analysis indicated an optimal SII cut-off value of 537.34, with an area under the curve (AUC) of 0.646, a sensitivity of 60%, and a specificity of 64.1% (P < 0.001).ConclusionThe SII revealed a significant positive association with a real-world fragility fracture event and a future 10-year fragility fracture probability in postmenopausal females with T2DM, particularly evident in individuals with anemia. Therefore, monitoring the SII and hemoglobin in postmenopausal older women with T2DM is helpful in routine clinical practice to identify individuals at high risk for fragility fractures and to promptly execute appropriate fracture intervention procedures.

Long-term nitrogen application decreased mineral-associated organic carbon while increasing particulate organic carbon in purple soil in southwest China

In recent years, anthropogenic activities have increased nitrogen (N) input into terrestrial ecosystems, profoundly impacting soil organic carbon (SOC) sequestration. However, the potential mechanisms through which N affects mineral-associated organic carbon (MAOC) and particulate organic carbon (POC) remain unclear. To address this gap, we conducted a 12-year field trial applying continuous N application (0, 90, 180, 270, and 360 kg N·ha−1) in a maize agro-ecosystem. We assessed plant biomass (yield, straw, and root biomass), microbial properties (enzyme activity, biomass, and diversity), soil chemistry (pH, N availability, and base ions), mineralogy (oxides and silicates), and SOC fractions to elucidate the primary control mechanisms influencing MAOC and POC. Our findings showed that N application increased SOC and POC by 6.56%–10.4% and 43.1%–54.0%, respectively, but decreased MAOC by 7.31%–17.1%. And N application increased plant biomass, but decreased soil pH (pH from 6.7 to 5.6), base ion concentrations (K⁺, Na⁺, Ca2⁺, Mg2⁺), amorphous oxides, and illite content. Partial least squares path model (PLS-PM) and correlation analyses indicated that N application enhances root biomass while increasing microbial decomposition, and ultimately their combined effect increased POC. The decline in MAOC is primarily attributed to soil acidification decreasing the C input from microbial residues, altering mineral composition and diminishing the minerals' capacity to protect SOC. Thus, our study demonstrates that N addition predominantly increases POC through enhanced root biomass, while reducing MAOC by decreasing microbial biomass and weakening mineral protection. These insights provide a deeper understanding of the mechanisms governing SOC fraction dynamics in answer to N inputs in agroecosystems.

Decoupling the Impacts of Climate Change and Human Activities on Terrestrial Vegetation Carbon Sink

Net ecosystem productivity (NEP) plays a vital role in quantifying the carbon exchange between the atmosphere and terrestrial ecosystems. Understanding the effects of dominant driving forces and their respective contribution rates on NEP can aid in the effective management of terrestrial carbon sinks, especially in rapidly urbanizing coastal areas where climate change (CC) and human activities (HA) occur frequently. Combining MODIS NPP products and meteorological data from 2000 to 2020, this paper established a Modis NPP-Soil heterotrophic respiration (Rh) model to estimate the magnitude of NEP in China’s coastal zone (CCZ). Hotspot analysis, variation trend, partial correlation, and residual analysis were applied to explore the spatiotemporal patterns of NEP and the contributions of CC and HA to the dynamics of NEP. We also explored the changes in NEP in different land use types. It was found that there is a clear north–south difference in the spatial pattern of NEP in CCZ, with Zhejiang Province serving as the main watershed for this difference. In addition, NEP in most regions showed an improvement trend, especially in the Beijing–Tianjin–Hebei region and Shandong Province, but the pixel values of NEP here were generally not as high as that in most southern provinces. According to the types of driving forces, the improvement of NEP in these regions primarily results from the synergistic effects of CC and HA. NEP changes in provinces south of Zhejiang are mainly dominated by single-factor-driven degradation. The area where HA contributes to the increase in NEP is much larger than that of CC. From the perspective of land use types, forests and farmland are the dominant contributors to the magnitude of NEP in CCZ.