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The Inner Mongolia Autonomous Region is an ecological protective screen in the northern part of China. The precipitable water vapor (PWV) products with high precision and spatiotemporal resolution are critical for climate research in this region. This study aims to comprehensively evaluate and analyze the PWV in Inner Mongolia using the global navigation satellite system (GNSS), radiosonde (RS), the fifth-generation European Center for Medium-Range Weather Forecasts Reanalysis (ERA5), and the Second Modern-Era Retrospective Analysis for Research and Applications (MERRA-2) data. The comparison between GNSS PWV and RS PWV reveals an average bias of −0.68 mm and a root mean square error (RMSE) of 2.17 mm, indicating the high accuracy of GNSS PWV and its potential as an assessment tool of other PWV products. In comparison to PWV of GNSS, PWV of ERA5 and MERRA-2 exhibit an annual average bias of 0.17 and 0.39 mm, respectively, and an annual average RMSE of 1.63 and 2.99 mm, respectively. The monthly average bias and RMSE of ERA5 are 0.41 and 1.79 mm, respectively, while those of MERRA-2 are 0.43 and 3.05 mm, respectively. In the Inner Mongolia region, the diurnal anomaly variation range of PWV for all three datasets is stable within −0.6–0.6 mm. The evaluation results demonstrate that PWV retrieved by ERA5 and MERRA-2 are applicable in the Inner Mongolia region, with ERA5 showing better consistency with GNSS PWV. This study provides valuable insights for understanding the formation, patterns, monitoring, and warning of meteorological natural disasters in the Inner Mongolia region. [ABSTRACT FROM AUTHOR]

Atmospheric precipitable water vapor (PWV) is a very important meteorological factor for weather forecasting and climate change monitoring. GNSS and ERA5 PWV from 2010 to 2022 are used to analyze the mean distribution and interdecadal trend of PWV in North America. The mean PWV is less than 20 mm in most regions of North America except for the Southeast. Overall, there is a significant increase along the Atlantic coast region of southeast North America and near the Gulf of California. ERA5-PWV values from 1940 to 2022 are used to analyze the interdecadal trend of PWV in North America. The results show that the trend of PWV remains unchanged for the east of Rocky Mountains. Most of the other regions are experiencing extremely significant increases, with the fastest rising interdecadal trend of around 1.2 mm decade−1 in summer near the Gulf of California. The results illustrate that there is a significant correlation between PWV and temperature with the correlation coefficient of 0.96, and that there are some differences between the actual increase and ideal increase of water vapor derived from Clausius-Clapeyron equation for every 1 K increase in North America. In addition, the response of PWV to ENSO in North America includes a delay of six to ten months and a fluctuation from 1.5 to 3 mm after El Niño events. The results indicate that ENSO events have an important influence on PWV change, and the effect of ENSO on PWV in tropical regions is greater than that in temperate regions. [ABSTRACT FROM AUTHOR]

We analyzed the overall variation, spatial distribution, and diurnal variation of precipitable water vapor (PWV) in Northwest China based on ground-based global navigation satellite systems (GNSS) water vapor detection, hourly surface precipitation, and ERA5 reanalysis data from March 2021 to March 2023. Then, we discussed how different meteorological factors influence PWV. The results show that: (1) In Northwest China, PWV is low in the west but high in the east. East of Northwest China frequently has high values, with an annual average of 28.21 mm at the center, whereas the central part of the Qinghai Plateau and Slopes frequently has low values. In Northwest China, especially East of Northwest China, PWV is negatively correlated with altitude. (2) The annual average PWV variation is unimodal in all precipitation climate zones. The average PWV decreases and reaches its minimum from November to March, increases rapidly and reaches its maximum in mid to early July, decreases gradually, decreases rapidly after September, and stabilizes at a low level thereafter. (3) The analysis of diurnal PWV variation at five representative stations in Northwest China indicates that the average diurnal PWV variation is affected by both diurnal and semidiurnal cycles. The semidiurnal cycle is prominent at Zhangye station in Hexi Corridor in autumn, and the diurnal cycle dominates at all other stations, with a variance contribution of the diurnal cycle of greater than 75% and an amplitude of 0.2–0.88 mm. The average diurnal PWV variation reaches its minimum at 08:00–12:00 and reaches its maximum at 16:00–21:00. The exact time that the average diurnal PWV variation reaches its minimum and maximum varies depending on the season. (4) In Northwest China, in summer, the average PWV on days with precipitation is higher than on days without precipitation. PWV increases with the increase in precipitation, most significantly in summer and autumn. However, this increase is not significant when precipitation is smaller than 10 mm. Moreover, the PWV increase with precipitation is not prominent in South and North Xinjiang. [ABSTRACT FROM AUTHOR]

The geostationary meteorological satellite Fengyun-4A (FY-4A) has rapidly advanced, generating abundant high spatiotemporal resolution atmospheric precipitable water vapor (PWV) products. However, remote sensing satellites are vulnerable to weather conditions, and these latest operational PWV products still require systematic validation. This study presents a comprehensive evaluation of FY-4A PWV products by separately using PWV data retrieved from radiosondes (RS) and the Global Navigation Satellite System (GNSS) from 2019 to 2022 in China and the surrounding regions. The overall results indicate a significant consistency between FY-4A PWV and RS PWV as well as GNSS PWV, with mean biases of 7.21 mm and −8.85 mm, and root mean square errors (RMSEs) of 7.03 mm and 3.76 mm, respectively. In terms of spatial variability, the significant differences in mean bias and RMSE were 6.50 mm and 2.60 mm between FY-4A PWV and RS PWV in the northern and southern subregions, respectively, and 5.36 mm and 1.73 mm between FY-4A PWV and GNSS PWV in the northwestern and southern subregions, respectively. The RMSE of FY-4A PWV generally increases with decreasing latitude, and the bias is predominantly negative, indicating an underestimation of water vapor. Regarding temporal differences, both the monthly and daily biases and RMSEs of FY-4A PWV are significantly higher in summer than in winter, with daily precision metrics in summer displaying pronounced peaks and irregular fluctuations. The classic seasonal, regional adjustment model effectively reduced FY-4A PWV deviations across all regions, especially in the NWC subregion with low water vapor distribution. In summary, the accuracy metrics of FY-4A PWV show distinct spatiotemporal variations compared to RS PWV and GNSS PWV, and these variations should be considered to fully realize the potential of multi-source water vapor applications. [ABSTRACT FROM AUTHOR]

BACKGROUND Increased aortic blood pressure (BP) and arterial stiffness are associated with higher cardiovascular risk in hemodialysis. Previous works showed that lower dialysate sodium is associated with lower brachial-BP; data on aortic-BP and arterial stiffness are limited. This study aimed to investigate the effects of different dialysate sodium concentrations on 72-hour aortic-BP and arterial stiffness parameters in hemodialysis patients. METHODS This analysis is part of a prospective, non-randomized interventional study. Twenty-five hemodialysis patients underwent a set of 3 periods of different dialysate sodium concentrations; 6 sessions with dialysate sodium of 137 mEq/l, followed consecutively by 6 sessions with 139 mEq/l and, finally, 6 sessions with 141 mEq/l. At the start of the sixth hemodialysis session on each sodium concentration, 72-hour ABPM (Mobil-O-Graph) was performed to evaluate aortic-BP and arterial stiffness indices during the overall 72-hour, different 24-hour, daytime, and nighttime periods. RESULTS Mean 72-hour aortic systolic blood pressure (SBP)/diastolic blood pressure (DBP) were higher with increasing dialysate sodium concentrations (137 mEq/l: 114.2 ± 15.3/77.0 ± 11.8 mm Hg vs. 139 mEq/l: 115.4 ± 17.3/77.9 ± 14.0 mm Hg vs. 141 mEq/l: 120.5 ± 18.4/80.5 ± 14.7 mm Hg, P  = 0.002/ P  = 0.057, respectively). Wave-reflection parameters (AIx, AIx(75), AP) were not significantly different between the 3 dialysate sodium concentrations. Ambulatory pulse wave velocity (PWV) was significantly higher with increasing dialysate sodium concentrations (137 mEq/l: 8.5 ± 1.7 m/s vs. 139 mEq/l: 8.6 ± 1.6 m/s vs. 141 mEq/l: 8.8 ± 1.6 m/s, P  < 0.001). In generalized linear mixed models including 72-hour brachial SBP as a random covariate, the adjusted marginal means of 72-hour PWV were not significantly different between groups. CONCLUSIONS This study showed that higher dialysate sodium concentrations are associated with significant increases in ambulatory aortic BP and PWV. These findings further support the need for modification of dialysate sodium concentration in hemodialysis. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the long-term effect of body composition, physical activity, and cardiorespiratory fitness (CRF) from puberty on arterial health in late adolescent males. Methods: The cumulative burden of physical activity (measured with accelerometer), CRF (VO2peak0.82), and body composition (body mass index, fat mass, and fat percentage) from puberty to late adolescence (sum of 4 time points from 12 to 18 y) was assessed in 102 males. Additional analysis on the first (T1) and last (T4) time points was performed. Intima-media thickness (IMT), carotid-femoral pulse wave velocity, and augmentation index adjusted to heart rate of 75 beats per minute (bpm) as dependent variables were measured at T4 and analyzed in multivariable regression models adjusted for known risk factors including maturation, blood pressure, and smoking habits. Results: T1 and cumulative body composition measures were independently associated with IMT, while cumulative (β = −0.011, P =.036) and T4 (β = −0.0.031, P =.001) CRF revealed independent associations with IMT. Individuals with moderate to vigorous physical activity >60 minutes per day at T1 showed relationship (β = −1.091, P =.026) with IMT independently of late adolescent physical activity. No significant relationship was present for arterial function. Conclusion: Arterial structure in adolescent males is associated with physical activity at 12 years while relationship with CRF can be seen in late adolescence and cumulatively from puberty to late adolescence. [ABSTRACT FROM AUTHOR]

Background/Objectives: Controlling hypertension may reduce the risk of cognitive impairment. A marker for the identification of hypertensive patients who are more likely to suffer cognitive impairment would be of clinical benefit. In our research, 105 patients with newly diagnosed primary hypertension were assessed at the Department of Neurology, the University of Debrecen. Methods: The available data covered detailed medical history and data, the results of different tests, ambulatory blood pressure monitoring, the intima–media thickness, the flow-mediated dilatation, the augmentation index, the pulse wave velocity, and neuropsychological evaluation. Multiple linear regression models were created to evaluate the associations found in simple analyses (Spearman's rank correlation and Pearson's chi-squared test). Results: The flow-mediated dilatation showed significant correlations with working memory, attention, learning, and executive functions. The intima–media thickness showed significant correlations with attention and reaction time. The composite flow-mediated dilatation/IMT ratio showed a significant relationship with the overall index of cognitive functions. Based on our results, a flow-mediated dilatation/IMT ratio of 15 represents a cut-off value. The pulse wave velocity showed a significant correlation with working memory and attention. The augmentation index showed significant relationships with reaction time and executive functions. Conclusions: Based on our results, the intima–media thickness, flow-mediated dilatation, and their ratio are suitable for the identification of a particularly vulnerable subgroup of patients for whom a detailed cognitive examination is required for the early detection and treatment of functional disorders. The assessment of attention, executive functions, working memory, and reaction time is required in early hypertension. [ABSTRACT FROM AUTHOR]

Since the land 2 m air temperature from European Centre for Medium-Range Weather Forecasts Reanalysis 5 (ERA5-land) is vulnerable to interference by regional climate characteristics and local topography, how to objectively and accurately evaluate its accuracy and then establish a refined model is the key to improve its multifaceted and deep-level applications. This study proposed a systematic and complete refinement method for ERA5-land air temperature based on the densely distributed weather stations in Shandong Province in eastern China, including the compensation of elevation matching bias (EMB) caused by ASTER GDEM and the overall refinement using the remove-and-restore model (RRM). Taking the hottest July and the coldest December in this area, surface air temperature, atmospheric weighted mean temperature (Tm) and GNSS precipitable water vapor (PWV) were used to verify the feasibility of this method. The results show that: (1) Whether the temperature is high in July or low in December, the accuracy can be improved by about 42.2 % when the refinement method was used. Especially for high altitude areas (the summit of Mount Tai, 1553 m above sea level), the accuracy can be improved by 74.5 %. (2) In contrast to only the temperature lapse rate (TLR) correction, the average root mean square (RMS) can be reduced by 7.4 % and 60.4 % in July and 7.0 % and 59.5 % in December for the met stations less than 150 m in altitude and the peak station of Mount Tai, respectively, when the new method was used. (3) Compared with the Tm and PWV computed by interpolated temperature without any correction, the accuracy of Tm can be improved by 31.2 % and 34.1 % in July and December for weather station in the altitude of 100 ∼ 350 m after the TLR correction, EMB compensation and RRM refinement successively. Meanwhile, the accuracy of PWV can be improved by 47.8 % in July and 42.0 % in December, respectively, and especially for PWV high-value moments. Besides, after correction by RRM, both Tm and PWV in low altitude areas achieve at least 20 % accuracy improvement. In summary, the systematic and complete refinement method proposed in this study are important to significantly improve the ERA5-land 2 m temperature availability and GNSS PWV accuracy, and the compensation of EMB is mainly effective for high altitude areas. [ABSTRACT FROM AUTHOR]

To address the challenge of difficulty in selecting hyperparameters for gated recurrent units (GRU), a combined model (CNN-GRU-SSA) was proposed, integrating convolutional neural networks (CNN), gated recurrent units, and the sparrow search algorithm (SSA). Firstly, CNN for feature extraction from the multidimensional input dataset was utilized. Subsequently, the features extracted by CNN into the GRU model are inputted. Lastly, the hyperparameters of the GRU model using the SSA algorithm were optimized and were applied to the model to predict PM2.5 concentrations. Chengdu in the western region and Hangzhou in the eastern region was selected as research areas. Hourly data of air pollutants, meteorological factors, boundary layer height (BLH), and precipitable water vapor (PWV) from December 1, 2021, to February 13, 2022, were utilized for modeling. The aim was to predict the variation in PM2.5 concentrations in both cities from February 14 to February 28, 2022. Experimental results indicate that the CNN-GRU-SSA model demonstrates a noticeable improvement in prediction accuracy compared to other models, with Chengdu exhibiting the closest proximity between predicted and actual values. [ABSTRACT FROM AUTHOR]

Abstract Background Arteriosclerosis significantly impacts cardiovascular health. Pulse wave velocity has emerged as a valuable non-invasive method for assessing arterial stiffness. A negative association between carotid-femoral pulse wave velocity (cfPWV) and cerebral blood flow has been reported, suggesting a link between arterial stiffness and reduced cerebral blood flow. We aimed to determine whether a correlation exists between cfPWV and blood flow in the internal carotid artery (ICA) and to assess the influence of age and body mass index (BMI) on cfPWV in healthy individuals. Methods Thirty-six healthy subjects (23 males and 13 females) with no underlying medical conditions and who were not on regular medications were enrolled in the study. Arterial stiffness was assessed by measuring the cfPWV using Vicorder® software. ICA blood flow parameters were measured using high-resolution ultrasound. ICA diameter was measured using automated edge-detection software. Results Significant positive correlations were found between cfPWV and age (Spearman’s rho coefficient 0.33, p = 0.04), BMI (Spearman’s rho coefficient 0.32, p = 0.05), and ICA diameter (Pearson’s coefficient 0.35, p = 0.03). No significant correlations were observed between cfPWV and ICA peak systolic velocities (PSV; p = 0.22), or resistive index (RI; p = 0.76), nor between age and ICA diameter (p = 0.42), PSV (p = 0.09), or RI (p = 0.89). Conclusion Our findings demonstrate a positive correlation between arterial stiffness, age, and BMI in a healthy population, along with an association between increased ICA diameter and arterial stiffness. The lack of correlation between cfPWV and ICA blood flow parameters suggests that the ICA may dilate as a compensatory mechanism to mitigate the effects of increased arterial stiffness, ensuring optimal cerebral blood flow in healthy individuals.

Precipitable water vapor (PWV) is one of the most dynamic components of the atmosphere, playing a critical role in precipitation formation, the hydrological cycle, and climate change. This study used SuomiNet Global Positioning System (GPS) data from April 2021 to June 2023 in the United States to comprehensively evaluate 3 and 6 h Global Forecast System (GFS) PWV products (i.e., PWV3h and PWV6h). There was high consistency between the GFS PWV and GPS PWV data, with correlation coefficients (Rs) higher than 0.98 and a root mean square error (RMSE) of about 0.23 cm. The PWV3h product performed slightly better than PWV6h. PWV tended to be underestimated when PWV > 4 cm, and the degree of underestimation increased with increasing water vapor value. The RMSE showed obvious seasonal and diurnal variations, with the RMSE value in summer (i.e., 0.280 cm) considerably higher than in winter (i.e., 0.158 cm), and nighttime were RMSEs higher than daytime RMSEs. Clear-sky conditions showed smaller RMSEs, while cloudy-sky conditions exhibited a smaller range of monthly RMSEs and higher Rs. PWV demonstrated a clear spatial pattern, with both Rs and RMSEs decreasing with increasing elevation and latitude. Based on these temporal and spatial patterns, Back Propagation neural network and random forest (RF) models were employed, using PWV, Julian day, and geographic information (i.e., latitude, longitude, and elevation) as input data to correct the GFS PWV products. The results indicated that the RF model was more advantageous for water vapor correction, improving overall accuracy by 12.08%. In addition, the accuracy of GFS PWV forecasts during hurricane weather was also evaluated. In this extreme weather, the RMSE of the GFS PWV forecast increased comparably to normal weather, but it remained less than 0.4 cm in most cases. [ABSTRACT FROM AUTHOR]

Background: Arteriosclerosis significantly impacts cardiovascular health. Pulse wave velocity has emerged as a valuable non-invasive method for assessing arterial stiffness. A negative association between carotid-femoral pulse wave velocity (cfPWV) and cerebral blood flow has been reported, suggesting a link between arterial stiffness and reduced cerebral blood flow. We aimed to determine whether a correlation exists between cfPWV and blood flow in the internal carotid artery (ICA) and to assess the influence of age and body mass index (BMI) on cfPWV in healthy individuals. Methods: Thirty-six healthy subjects (23 males and 13 females) with no underlying medical conditions and who were not on regular medications were enrolled in the study. Arterial stiffness was assessed by measuring the cfPWV using Vicorder® software. ICA blood flow parameters were measured using high-resolution ultrasound. ICA diameter was measured using automated edge-detection software. Results: Significant positive correlations were found between cfPWV and age (Spearman's rho coefficient 0.33, p = 0.04), BMI (Spearman's rho coefficient 0.32, p = 0.05), and ICA diameter (Pearson's coefficient 0.35, p = 0.03). No significant correlations were observed between cfPWV and ICA peak systolic velocities (PSV; p = 0.22), or resistive index (RI; p = 0.76), nor between age and ICA diameter (p = 0.42), PSV (p = 0.09), or RI (p = 0.89). Conclusion: Our findings demonstrate a positive correlation between arterial stiffness, age, and BMI in a healthy population, along with an association between increased ICA diameter and arterial stiffness. The lack of correlation between cfPWV and ICA blood flow parameters suggests that the ICA may dilate as a compensatory mechanism to mitigate the effects of increased arterial stiffness, ensuring optimal cerebral blood flow in healthy individuals. [ABSTRACT FROM AUTHOR]

Precipitation water vapor (PWV) is an important parameter in numerical weather forecasting and climate research. However, existing PWV adjustment models lack comprehensive consideration of seasonal and geographic factors. This study utilized the General Regression Neural Network (GRNN) algorithm and Global Navigation Satellite System (GNSS) PWV in China to construct and evaluate European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis (ERA5) PWV adjustment models for various seasons and subregions based on meteorological parameters (GMPW model) and non-meteorological parameters (GFPW model). A linear model (GLPW model) was established for model accuracy comparison. The results show that: (1) taking GNSS PWV as a reference, the Bias and root mean square error (RMSE) of the GLPW, GFPW, and GMPW models are about 0/1 mm, which better weakens the systematic error of ERA5 PWV. The overall Bias of the GLPW, GFPW, and GMPW models in the Northwest (NWC), North China (NC), Tibetan Plateau (TP), and South China (SC) subregions is approximately 0 mm after adjustment. The adjusted overall RMSE of the GLPW, GFPW, and GMPW models of the four subregions are 0.81/0.71/0.62 mm, 1.15/0.95/0.77 mm, 1.66/1.26/1.05 mm, and 2.11/1.35/0.96 mm, respectively. (2) The accuracy of the three models is tested using GNSS PWV, which is not involved in the modeling. The adjusted overall RMSE of the GLPW, GFPW, and GMPW models in the four subregions are 0.89/0.85/0.83 mm, 1.61/1.58/1.27 mm, 2.11/1.75/1.68 mm and 3.65/2.48/1.79 mm, respectively. As a result, the GFPW and GMPW models have better accuracy in adjusting ERA5 PWV than the linear model GLPW. Therefore, the GFPW and GMPW models can effectively contribute to water vapor monitoring and the integration of multiple PWV datasets. [ABSTRACT FROM AUTHOR]

The national Beidou Navigation Satellite System (BDS) ground-based augmentation network (BGAN) of China is constructed with the existing GNSS observation resources of industrial sectors and local governments, based on the concept of joint building and sharing with sustainable development. This study provides a detailed introduction to the design, construction and operation of a meteorological application system based on BGAN, and validation of its water vapor products. BDS and GPS real-time observation of atmospheric water vapor is achieved nationwide in China and multi-GNSS applications. Through the application of multi-GNSS data and validation of the water vapor products from 2018 to 2020, the accuracy of precipitable water vapor (PWV) derived from BDS only is equivalent to that from GPS only. The root mean square error (RMSE) between them is about 2 mm with high correlation coefficient. Based on radiosonde data, the validation is conducted with the products of BDS-PWV, GPS-PWV, and Combined-PWV derived with multi-GNSS of BDS and GPS. The error characteristics of the three products show a consistent trend over the months. The bias is relatively small. The RMSE of the three products is in the range of 2.18–2.73 mm. The BDS-PWV has the largest RMSE, followed by GPS-PWV, and Combined-PWV has the smallest RMSE. [ABSTRACT FROM AUTHOR]

Abstract Background Use of sodium-glucose-cotransporter-2 (SGLT2) inhibitors often causes an initial decline in glomerular filtration rate (GFR). This study addresses the question whether the initial decline of renal function with SGLT2 inhibitor treatment is related to vascular changes in the systemic circulation. Methods We measured GFR (mGFR) and estimated GFR (eGFR) in 65 patients with type 2 diabetes (T2D) at baseline and after 12 weeks of treatment randomized either to a combination of empagliflozin and linagliptin (SGLT2 inhibitor based treatment group) (n = 34) or metformin and insulin (non-SGLT2 inhibitor based treatment group) (n = 31). mGFR was measured using the gold standard clearance technique by constant infusion of inulin. In addition to blood pressure (BP), we measured pulse wave velocity (PWV) under standardized conditions reflecting vascular compliance of large arteries, as PWV is considered to be one of the most reliable vascular parameter of cardiovascular (CV) prognosis. Results Both mGFR and eGFR decreased significantly after initiating treatment, but no correlation was found between change in mGFR and change in eGFR in either treatment group (SGLT2 inhibitor based treatment group: r=-0.148, p = 0.404; non-SGLT2 inhibitor based treatment group: r = 0.138, p = 0.460). Noticeably, change in mGFR correlated with change in PWV (r = 0.476, p = 0.005) in the SGLT2 inhibitor based treatment group only and remained significant after adjustment for the change in systolic BP and the change in heart rate (r = 0.422, p = 0.018). No such correlation was observed between the change in eGFR and the change in PWV in either treatment group. Conclusions Our main finding is that after initiating a SGLT2 inhibitor based therapy an exaggerated decline in mGFR was related with improved vascular compliance of large arteries reflecting the pharmacologic effects of SGLT2 inhibitor in the renal and systemic vascular bed. Second, in a single patient with T2D, eGFR may not be an appropriate parameter to assess the true change of renal function after receiving SGLT2 inhibitor based therapy. Trial registration clinicaltrials.gov (NCT02752113).

Heart failure with preserved ejection fraction (HFpEF) is a major health concern. There is a growing recognition of the causal interplay between arterial stiffness and HFpEF. We recently reported that phosphate retention is a trigger for arterial stiffness. This study focuses on whether arterial stiffness due to phosphate retention could be a predictor for HFpEF. Methods: The subjects of this study were 158 patients (68 males and 90 females, mean age 74.8 ± 11.2). HFpEF was defined according to the guidelines of the ESC 2019. Pulse wave velocity (PWV) and central systolic blood pressure (CSBP) were used as markers for arterial stiffness and afterload, respectively. We measured serum levels of fibroblast growth factor 23 (FGF23) as a marker of phosphate retention. Results: The serum levels of FGF23 had a significant relationship with PWV. PWV had significant relationships with LV mass index, plasma BNP levels, and relative wall thickness, e′, and E/e′ (p < 0.001, respectively). Multivariate logistic regression analysis revealed that higher PWV values and hypertension were significant predictors for the dependent factor (HFpEF). Arterial stiffness amplified afterload, leading to LV concentric hypertrophy and diastolic dysfunction. This study presents that arterial stiffness is a key predictor of HFpEF, and that phosphate retention is involved in the pathology of HFpEF.

Along with regular position-related applications, observations from navigation satellite constellations can also be utilised for atmospheric studies. The present study deals with the 3D water vapour tomography carried out for the first time using Indian GPS stations set up in the Himalayan region. A voxel-based approach is applied to retrieve the vertical profile of precipitable water vapour (PWV). Horizontal 4×4 grids have been formed between 29°–31° latitude and 77.5°–79.5° longitude with 0.5° spatial resolution. To construct a tomography model, voxels are formed over these grids up to 10 km with 0.5 km vertical resolution. Water vapour density (WVD) is estimated for different days to observe its variations under different atmospheric conditions. The results show that the estimated vertical variation of water vapour closely matches the AIRS WVD profile. To compare the results, AIRS WVD observations are interpolated at the same altitude where the tomographic estimations are available. The average root mean square (RMS) error, standard deviation (SD), and mean absolute error (MAE) between estimated water vapour density and AIRS WVD are observed to be 1.52, 1.32 and 2.02 g/m3, respectively. The coefficient of determination (R2) value is observed to be close to 0.9, reflecting an excellent linearity between estimated and observed values. The results also show that the WVD is high up to the 5 km voxel and it is between 0 and 5 g/m3 above 5 km altitude. A good estimation of vertical water vapour profile has been obtained using CORS observations and can be used for further atmospheric analyses in this region. [ABSTRACT FROM AUTHOR]

Precipitable water vapour (PWV) available in the lower atmosphere plays a very crucial role in the determination of potential rainfall over an area and its early detection is very important for predicting heavy rainfall events. Hence, precise estimation of PWV is necessary for weather forecasting and other atmospheric analysis. In the present study, global positioning system (GPS) derived PWV is used for the prediction of short-term rainfall. The GPS observations acquired from the HYDE (Hyderabad) and IISc (Bengaluru) IGS stations and meteorological observations obtained from weather stations are used for the retrieval of PWV. Thereafter, estimated PWV values are used in a rain prediction algorithm. A relationship is established between hourly estimated PWV values and ERA5 reanalysis rainfall data to forecast the rainfall event. The validation of estimated results is carried out at different levels. Estimated zenith tropospheric delay (ZTD) results are compared with IGS results which show a good agreement with RMS errors close to 5 mm in different cases. Further estimated PWVs are compared with the ERA5 PWVs, which show a difference of 2–4 mm considering all the datasets. Subsequently, this validated PWV is used in rainfall detection analysis and results show that 56.6% of the rain events can be forecasted with a false alarm rate of 42.3% in the region around IISc and 52.2% of the rain events can be forecasted with a false alarm rate of 43.9% in the region around HYDE. A good prediction is observed for IISc as compared to HYDE. Considering different threshold values of different years, it is observed that 70% and 60% rain events can be forecasted for IISc and HYDE, respectively. The analysis shows that by using GPS PWV, an accurate prediction of rainfall is possible and this can be used further for weather prediction analyses over the region. [ABSTRACT FROM AUTHOR]

Heart failure with preserved ejection fraction (HFpEF) is a major health concern. There is a growing recognition of the causal interplay between arterial stiffness and HFpEF. We recently reported that phosphate retention is a trigger for arterial stiffness. This study focuses on whether arterial stiffness due to phosphate retention could be a predictor for HFpEF. Methods: The subjects of this study were 158 patients (68 males and 90 females, mean age 74.8 ± 11.2). HFpEF was defined according to the guidelines of the ESC 2019. Pulse wave velocity (PWV) and central systolic blood pressure (CSBP) were used as markers for arterial stiffness and afterload, respectively. We measured serum levels of fibroblast growth factor 23 (FGF23) as a marker of phosphate retention. Results: The serum levels of FGF23 had a significant relationship with PWV. PWV had significant relationships with LV mass index, plasma BNP levels, and relative wall thickness, e′, and E/e′ (p < 0.001, respectively). Multivariate logistic regression analysis revealed that higher PWV values and hypertension were significant predictors for the dependent factor (HFpEF). Arterial stiffness amplified afterload, leading to LV concentric hypertrophy and diastolic dysfunction. This study presents that arterial stiffness is a key predictor of HFpEF, and that phosphate retention is involved in the pathology of HFpEF. [ABSTRACT FROM AUTHOR]

Background: Use of sodium-glucose-cotransporter-2 (SGLT2) inhibitors often causes an initial decline in glomerular filtration rate (GFR). This study addresses the question whether the initial decline of renal function with SGLT2 inhibitor treatment is related to vascular changes in the systemic circulation. Methods: We measured GFR (mGFR) and estimated GFR (eGFR) in 65 patients with type 2 diabetes (T2D) at baseline and after 12 weeks of treatment randomized either to a combination of empagliflozin and linagliptin (SGLT2 inhibitor based treatment group) (n = 34) or metformin and insulin (non-SGLT2 inhibitor based treatment group) (n = 31). mGFR was measured using the gold standard clearance technique by constant infusion of inulin. In addition to blood pressure (BP), we measured pulse wave velocity (PWV) under standardized conditions reflecting vascular compliance of large arteries, as PWV is considered to be one of the most reliable vascular parameter of cardiovascular (CV) prognosis. Results: Both mGFR and eGFR decreased significantly after initiating treatment, but no correlation was found between change in mGFR and change in eGFR in either treatment group (SGLT2 inhibitor based treatment group: r=-0.148, p = 0.404; non-SGLT2 inhibitor based treatment group: r = 0.138, p = 0.460). Noticeably, change in mGFR correlated with change in PWV (r = 0.476, p = 0.005) in the SGLT2 inhibitor based treatment group only and remained significant after adjustment for the change in systolic BP and the change in heart rate (r = 0.422, p = 0.018). No such correlation was observed between the change in eGFR and the change in PWV in either treatment group. Conclusions: Our main finding is that after initiating a SGLT2 inhibitor based therapy an exaggerated decline in mGFR was related with improved vascular compliance of large arteries reflecting the pharmacologic effects of SGLT2 inhibitor in the renal and systemic vascular bed. Second, in a single patient with T2D, eGFR may not be an appropriate parameter to assess the true change of renal function after receiving SGLT2 inhibitor based therapy. Trial registration: clinicaltrials.gov (NCT02752113). [ABSTRACT FROM AUTHOR]

Background: Lipoprotein glomerulopathy (LPG) is a apolipoprotein E (ApoE)-related glomerular disease and has been associated with type III hyperlipidemia. Without appropriate treatment, chronic kidney disease (CKD) caused by LPG progresses, and approximately half of the patients develop end-stage kidney disease within 1–27 years of disease onset. However, few studies have highlighted the clinical course of cardiovascular diseases (CVDs) in patients with LPG. Herein, we report the first case of LPG in which the CVD risk was assessed using arterial stiffness. Case presentation: A 32-year-old Japanese man was referred to our hospital due to persistent proteinuria. Kidney biopsy showed markedly dilated capillary lumens containing pale-stained thrombi, which stained positively with Oil Red O. Electron microscopy revealed the presence of thrombi in the capillary lumen with low electron density and vacuoles of various sizes in part of the thrombi. Toluidine blue and Sudan IV stains were used to stain the thin sections of Epon-embedded tissue samples for electron microscopy. Sudan IV-positive droplets were observed in the capillary lumens, vascular walls, and cytoplasm of tubular cells. Increased serum ApoE concentration was observed. Liquid chromatography-tandem mass spectrometry of laser-microdissected glomeruli from paraffin sections revealed an increase in ApoE. Direct deoxyribonucleic acid sequencing of ApoE revealed a heterozygous ApoE Sendai mutation (Arg145Pro). The patient was finally diagnosed with LPG with heterozygosity for ApoE-Sendai mutation (Arg145Pro). Notably, at the time of diagnosis, he had markedly increased arterial stiffness for his age. Arterial stiffness was measured using brachial-ankle pulse wave velocity (baPWV), which was equivalent to that of a 56-year-old man. After three months of treatment with fenofibrate and losartan, a significant reduction in proteinuria was achieved along with an improvement in baPWV. Furthermore, these effects were maintained despite the lack of decrease in serum ApoE levels. Conclusion: Herein, we report the case of a patient with LPG with markedly increased arterial stiffness at the time of diagnosis, in whom combination therapy with fenofibrate and losartan successfully improved proteinuria and arterial stiffness. To the best of our knowledge, this is the first case report of LPG in which CVD risk was assessed using arterial stiffness. [ABSTRACT FROM AUTHOR]

Background: In this study we used Mendelian randomization (MR) to investigate the potential causal association of lipoprotein (a) [Lp(a)] levels with pulse wave velocity (PWV). Methods: Genetic variants associated with Lp(a) were retrieved from the UK Biobank GWAS (N = 290,497). A non‐ overlapping GWAS based on a European cohort (N = 7,000) was used to obtain genetic associations with PWV (outcome) and utilized two different measures for the same trait, brachial–ankle (baPWV) and carotid–femoral (cfPWV) PWV. We applied a two‐sample MR using the inverse variance weighting method (IVW) and a series of sensitivity analyses for 170 SNPs that were selected as instrumental variables (IVs). Results: Our analyses do not support a causal association between Lp(a) and PWV for neither measurement [βiwv(baPWV) = −.0005, p =.8 and βiwv(cfPWV) = −.006, p =.16]. The above findings were consistent across sensitivity analyses including weighted median, mode‐based estimation, MR‐Egger regression and MR‐PRESSO. Conclusion: We did not find evidence indicating that Lp(a) is causally associated with PWV, the gold standard marker of arterial stiffness. [ABSTRACT FROM AUTHOR]

Aims The clinical significance and feasibility of the recently described non-invasive parameters exploring ventricular–arterial coupling (VAC) remain uncertain. This study aimed to assess VAC parameters for prognostic stratification in stable patients with left ventricular ejection fraction (LVEF) ≥40% following myocardial infarction (MI). Methods and results Between 2018 and 2021, patients with LVEF ≥40% were evaluated 1 month following MI using transthoracic echocardiography (TTE) and arterial tonometry at rest and after a handgrip test. VAC was studied via the ratio between arterial elastance (Ea) and end-systolic LV elastance (Ees) and between pulse wave velocity (PWV) and global longitudinal strain (GLS). Patients were followed for major adverse cardiovascular events (MACE): all-cause death, acute heart failure, stroke, AMI, and urgent cardiovascular hospitalization. Among the 374 patients included, Ea/Ees and PWV/GLS were obtained at rest for 354 (95%) and 253 patients (68%), respectively. Isometric exercise was workable in 335 patients (85%). During a median follow-up of 32 months (interquartile range: 16–42), 41 (11%) MACE occurred. Patients presenting MACE were significantly older and had a higher prevalence of peripheral arterial disease, lower GLS, higher Ea, PWV, and PWV/GLS ratio. The Ea/Ees ratio and standard TTE parameters during isometric exercise were not associated with MACE. After adjustment, the PWV/GLS ratio was the only VAC parameter independently associated with outcome. Receiver operating characteristic curve analysis identified a PWV/GLS ratio >0.70 (Youden's index = 0.37) as the best threshold to identify patients developing MACE: hazard ratio (95% confidence interval) = 2.2 (1.14–4.27), P = 0.02. Conclusion The PWV/GLS ratio, assessed 1 month after MI, identifies a group of patients at higher risk of MACE providing additional value on top of conventional non-invasive parameters. [ABSTRACT FROM AUTHOR]

Background: Patients with chronic kidney disease (CKD) are likely to get valve calcification 10-20 years earlier than the normal population secondary to uremia. This condition is typically diagnosed through transthoracic echocardiography. Vascular calcification resulted in arterial stiffness and an increase in pulse wave velocity (PWV) in large elastic-type arteries. The intima-media complex acts as a stand-in marker for atherosclerosis and is where lipids are deposited during plaque development. Objective: This study aimed to estimate the prevalence of valvular and vascular calcifications in hemodialysis patients at Ain Shams Specialized Hospital, Cairo, Egypt. Patients and Methods: A crosssectional pilot study was conducted on 100 prevalent hemodialysis patients who were maintained on thrice-weekly hemodialysis sessions at Ain Shams Specialized Hospital in the period from January to June 2020. Echocardiography was performed to assess the presence of valvular calcification; PWV was measured to evaluate vascular stiffness. Intima-media thickness (IMT) and carotid plaques were detected using an echo-doppler study of the carotid arteries. Results: The study was conducted on 100 patients undergoing hemodialysis treatment for 6 months. Out of these, 55% of patients were males. Among the studied patients, 15% had mitral valve (MV) calcification, 61% had aortic valve (AV) calcification, and 17% had carotid plaques. Patients with calcification of the MV had an aortic PWV mean of 1.587 m/s. 53.33% of these patients had carotid plaques and the IMT mean was 6.567mm higher than the non-MV calcification group. Patients with aortic AV calcifications had a mean IMT of 5.038 mm and a higher percentage (22.95%) of carotid plaques compared to the non-aortic calcification group. Patients with carotid plaques had higher levels of aortic wave pulse velocity (mean 1.54 m/s) and IMT (mean 7.653mm). Also, there was a significant positive correlation between intimal medial thickness and aortic PWV (p-value= 0.003), and a significant negative correlation between IMT and ejection fraction (p-value=0.048*). Conclusions: Valvular calcification is widespread in individuals on hemodialysis, with AV calcification being more common than MV calcification. Hemodialysis patients with valvular calcifications had a higher incidence of carotid intimal thickness. Aortic wave pulse velocity correlated with increasing carotid intimal thickness and predicted arterial atherosclerosis. [ABSTRACT FROM AUTHOR]

Konstantinos G Moulakakis,1,&ast; Christos F Pitros,1,&ast; Ioannis T Theodosopoulos,2 Spyridon N Mylonas,3 John D Kakisis,2 Christos Manopoulos,4 Nikolaos PE Kadoglou5 1Department of Vascular Surgery, Patras University Hospital, University of Patras, Patras, Greece; 2Department of Vascular Surgery, “Attikon” University Hospital, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece; 3Department of Vascular and Endovascular Surgery, Faculty of Medicine and University Hospital of Cologne, University of Cologne, Cologne, 50937, Germany; 4Biofluid Mechanics and Biomedical Engineering Laboratory, Fluids Section, School of Mechanical Engineering, National Technical University of Athens, Athens, Greece; 5Medical School, University of Cyprus, Nicosia, Cyprus&ast;These authors contributed equally to this workCorrespondence: Konstantinos G Moulakakis, Associate Professor of Vascular Surgery, Vascular Surgery Department, Patras University Hospital, Patras, Greece, Tel +0030 6937357508, Email konmoulakakis@yahoo.grAbstract: It has been documented that large-artery stiffness is independently associated with increased cardiovascular risk and may potentially lead to heart and kidney failure and cerebrovascular disease. A systematic review of studies investigating changes in arterial stiffness in patients undergoing endovascular repair of aortic disease was conducted. In addition, a review of the available literature was performed, analyzing findings from studies using the cardio-ankle vascular index (CAVI) as a marker of arterial stiffness. Overall, 26 studies were included in the present analysis. Our research revealed a high heterogeneity of included studies regarding the techniques used to assess the aortic stiffness. Aortic stiffness was assessed by pulse wave velocity (PWV), elastic modulus (Ep), and augmentation index (AI). Currently a few studies exist investigating the role of CAVI in patients having an aortic aneurysm or undergoing endovascular aortic repair. The majority of studies showed that the treatment of an abdominal aortic aneurysm (AAA) either with open repair (OR) or endovascular aortic repair (EVAR) reduces aortic compliance significantly. Whether EVAR reconstruction might contribute a higher effect on arterial stiffness compared to OR needs further focused research. An increase of arterial stiffness was uniformly observed in studies investigating patients following thoracic endovascular aortic repair (TEVAR), and the effect was more pronounced in young patients. The effects of increased arterial stiffness after EVAR and TEVAR on the heart and the central hemodynamic, and an eventual effect on cardiac systolic function, need to be further investigated and evaluated in large studies and special groups of patients.Keywords: arterial stiffness, pulse wave velocity, PWV, cardio-ankle vascular index, CAVI, augmentation index, AI, aortic aneurysm, endovascular aortic aneurysm repair, EVAR, thoracic endovascular aortic aneurysm repair, TEVAR

Precipitable water vapor (PWV) is a crucial factor in regulating the Earth's climate. Moreover, it demonstrates a robust correlation with precipitation. Situated in a region known for the generation and development of tropical cyclones, Guangxi in China is highly susceptible to floods triggered via intense rainfall. The atmospheric water vapor in this area displays prominent spatiotemporal features, thus posing challenges for precipitation forecasting. The water vapor products within the MERRA-2 and ERA5 reanalysis datasets present an opportunity to overcome constraints associated with low spatiotemporal resolution. In this study, the PWV data derived from GNSS and meteorological measurements in Guangxi from 2016 to 2018 were used to evaluate the accuracy of MERRA-2 and ERA5 water vapor products and their relationship with water vapor variations during extreme rainfall. Using GNSS PWV as a reference, the average bias of MERRA-2 PWV and ERA5 PWV for heavy rainfall was −0.22 mm and 1.84 mm, respectively, with average RMSE values of 3.72 mm and 3.31 mm. For severe rainfall, the average bias of MERRA-2 PWV and ERA5 PWV was −0.14 mm and 2.92 mm, respectively, with average RMSE values of 4.28 mm and 4.01 mm. During heavy rainfall days from Days 178 to 184 in 2017, the average bias of MERRA-2 PWV and ERA5 PWV was 0.92 mm and 2.42 mm, respectively, with average RMSE values of 4.04 mm and 3.40 mm. The accuracy was highest at the Guiping and Hechi stations and lowest at the Hezhou and Rongshui stations. Furthermore, when comparing MERRA-2/ERA5 PWV with GNSS PWV and actual precipitation, the trends in the variations of MERRA-2/ERA5 PWV were generally consistent with GNSS PWV and aligned with the increasing or decreasing trends of actual precipitation. In addition, ERA5 PWV exhibited high accuracy. Before the onset of heavy rainfall, PWV has a sharp surge. During heavy rainfall, PWV reaches its peak value. Subsequently, after the cessation of heavy rainfall, PWV tends to stabilize. Therefore, the reanalysis data of PWV can effectively reveal significant changes in water vapor and actual precipitation during periods of heavy rainfall in the Guangxi region. [ABSTRACT FROM AUTHOR]

The diurnal cycle of convection plays an important role in clouds and water vapour distribution across the global tropics. In this study, we utilize integrated moisture derived from the global navigation satellite system (GNSS), satellite precipitation estimates from TRMM and merged infrared dataset to investigate links between variability in tropospheric moisture, clouds development and precipitation at a diurnal time scale. Over 16 years of observations were analysed to estimate the diurnal cycles for 42 sites that span across the global tropics and assess the GNSS precipitable water vapour suitability in tropical moisture variability studies. Results show that the GNSS technique can be successfully used for studies related to the high-resolution temporal variability of integrated atmospheric moisture and, thus, in the analysis of multi-scale interactions and clouds development. For most of the analysed cases, GNSS integrated humidity shows one daily maximum (regardless of the season), which is related to the afternoon precipitation and cloud top temperature daily minimum. Although diurnal integrated moisture variations typically do not exceed 2 mm (usually below 5% of the daily mean value), in favourable large-scale conditions such relatively small changes can lead to the development of convective clouds and can affect precipitation distribution. Thus, GNSS technology allows reliable monitoring of tropospheric moisture variability at a diurnal time scale, which can be leveraged for improved monitoring and prediction of high-impact weather. [ABSTRACT FROM AUTHOR]

In recent years, extreme rainfall events have frequently occurred frequently, and heavy rainfall can cause drastic changes in the troposphere. Therefore, achieving to achieve real-time high-precision numerical prediction of key tropospheric parameters during heavy rainfall has become a major problem in global navigation satellite system (GNSS) meteorology. In this paper, two extreme rainfall events in southern China (Guangdong region) and northern China (Shandong region) in 2022 are used as case studies. Twenty-four-hour real-time numerical forecasts of key tropospheric parameters (atmospheric weighted mean temperature (Tm), precipitable water vapor (PWV), and GNSS zenith tropospheric delay (ZTD)) are obtained using three models, namely, the HGPT2, GPT3, and WRF models. Two optimization models, i.e., WRFDA (am) and WRFDA (pre), are then constructed by assimilating two types of data (global upper air and surface weather observations and daily advanced microwave sounding unit A (AMSU-A) brightness temperature) based on the WRF model. The experimental results for heavy rainfall show that (1) the WRF model predicts the key tropospheric parameters with better accuracy than the HGPT2 and GPT3 models, and the WRFDA (pre) model predicts PWV and ZTD with the highest accuracy; (2) the WRFDA (pre) model achieves a higher accuracy than the WRF model in predicting PWV and ZTD, where the PWV prediction accuracy is improved relative to the WRF model (in the south: MAE: 32.7 %; RMSE: 33.9 %; MAPE: 36.8 %; in the north: MAE: 27.3 %; RMSE: 24.2 %; MAPE: 28.0 %); this model achieves an MAE of 2.17 cm and an RMSE of 2.70 cm in 24-h ZTD prediction in the south, while the MAE reaches 2.48 cm, and the RMSE is 3.18 cm in the north; (3) the models provide a higher forecast accuracy in the southern region than in the northern region for heavy rainfall. The WRFDA (pre) model provides a favourable ZTD accuracy at GNSS stations near the ocean, while the WRFDA (am) model provides a satisfactory ZTD accuracy at inland GNSS stations, and the WRFDA (am) model provides the highest ZTD prediction accuracy at GNSS stations above 100 m. [ABSTRACT FROM AUTHOR]

This work is the first attempt to investigate the accuracy and reliability of the Ina-CORS (Indonesian Continuously Operating Reference Stations) for meteorological applications. We used the standard procedures to determine and assess the precipitable water vapor (PWV) obtained from the Global Navigation Satellite System (GNSS) measurements. The GNSS-derived zenith tropospheric delay (ZTD) was estimated using the GAMIT software, and it was then converted to PWV using surface pressure measurements and the water vapor weighted mean temperature. The results were compared against those derived from the fifth generation of the European Centre for Medium-Range Weather Forecasts (ECMWF ERA5) data. Comparisons against the ECMWF ERA5 data reveal the following findings. Values for the mean bias and root mean square deviation (RMSD) of the GNSS-derived ZTD over the period 2011–2020 are −6.6 mm and 14.1 mm, respectively, representing the total percentage error of about 0.4%. The total errors from the surface pressure measurements and the calculations of water vapor weighted mean temperature introduce errors to the PWV values with the magnitude less than 1 mm. The GNSS-derived PWV values over Indonesia are comparable with those derived from the ECMWF ERA5 data. The mean bias and RMSD of PWV values are −0.60 mm and 2.59 mm, respectively. In addition, spatio-temporal variations of the GNSS-derived PWV can capture the main atmospheric features that are consistent with the other results deduced from long-term rainfall data. One of the features is the annual and semiannual cycles of PWV that largely correspond to the annual migration of the Asian-Australian monsoon system. Based on these results, we can conclude that the Ina-CORS is capable enough for accurate monitoring of the Indonesian weather and climate variations. [ABSTRACT FROM AUTHOR]

The existing smog-haze forecast methods less consider about the influence of precipitable water vapor, and most of the prediction methods do not effectively handle the model regression residuals, so the prediction accuracy is not very high. For these issues, the PM2. 5 daily mean value data of four cities in Guangxi (Nanning, Guilin, Wuzhou and Baise) in 2017 combining with the factors of air pollutants, meteorological factors and precipitable water vapor (PWV), ARIMA models of the whole year and each quarter are respectively established to make short-term prediction of daily average PM2. 5 concentration in this region. The forecast residuals of ARIMA model are respectively fitted with the feedforward neural network radical basis function (RBF) and multi-layer perceptron (MLP) in order to optimize ARIMA model. The results show, except Guilin, the prediction effect of quarterly ARIMA model is better than the annual ARIMA model, and the quarterly ARIMA-MLP neural network prediction accuracy is better than the quarterly ARIMA model, indicating that this kind of model can be used for regional PM2. 5 concentration prediction. [ABSTRACT FROM AUTHOR]

Atmospheric precipitable water vapor (PWV) is a key parameter to study and monitor weather changes. According to the characteristics of complex terrain, harsh climate environment and insufficient water vapor sampling rate in Xinjiang, the accuracy of the PWV data provided by the latest ERA5 and MERRA-2 atmospheric reanalysis data is analyzed, with the PWV (GNSS-PWV) from the data of 11 GNSS stations in Xinjiang in 2018 as the reference value. After verifying the accuracy with the sounding station PWV data, the accuracy of ERA5 and MERRA-2 PWV in Xinjiang is evaluated. The temporal and spatial variation characteristics of the PWV bias (Bias),root mean square error (RMSE) of the two types of analysis data and the diurnal anomaly variation are analyzed. The results show that:(1) The annual mean Bias of ERA5 and MERRA-2 in Xinjiang are -0. 97 and -1. 20 mm. The annual mean RMSE are 1. 81 and 2. 11 mm. The accuracy PWV in the two kinds of analysis is better. ERA5 PWV is slightly more accurate than MERRA-2 PWV. (2) The PWV accuracy of both analysis data has obvious seasonal variation, generally low in summer and high in winter. (3) In terms of the diurnal variation of PWV, the two analysis data show high consistency with GNSS-PWV, indicating better diurnal variation of PWV in Xinjiang. Therefore, the two reanalysis data have high accuracy and stability in the PWV of Xinjiang, and is an important data source to study the water vapor change in Xinjiang. [ABSTRACT FROM AUTHOR]

Every year the government and people suffer from the cost of damages caused by natural disasters such as hurricanes and floods. Thanks to Global Positioning System (GPS) permanent station data, today it is possible to determine the amount of Water Vapor (WV) very accurately and reliably. GPS signals pass through different layers of the atmosphere, such as the ionosphere and troposphere, and therefore they are delayed. A significant part of the delay is due to the troposphere, which is one of the serious sources of error in GPS. In this research, by using 5 GPS permanent stations located in the Arasbaran region, in northwest of Iran, the Precipitable Water Vapor (PWV) is evaluated in order to show the capacity of this method in forecasting the October 2012 flood over the region. The results showed that the amount of PWV in the atmosphere had increased by 2 mm a few hours before the flood, which could be used as a forecast indicator. The Tikhonov regularization for tropospheric tomography covering the GPS stations region was also performed for latitude and altitude components for 3 consecutive days: the day before the flood, the flood day, and the day after the flood. A high amount of PWV was observed in the troposphere on the day before the flood, and especially on the flood day. During the study period, the results from tomography and the radiosonde were in good agreement, with a significance correlation of around 0.95. Also, the values of PWV obtained from GPS and MODIS-NIR do not have an absolute error more than 4.4 mm over the 8 days from 8 October 2012 to 15 October 2012. [ABSTRACT FROM AUTHOR]

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Aim:Celiac disease is associated with an increased risk of cardiovascular disease due to inflammation and autoimmunity involved in its pathophysiology. We aimed to evaluate vascular involvement in children with celiac disease based on their augmentation index, carotid pulse wave velocity, carotid intima-media thickness, echocardiographic findings, and blood pressure.Materials and Methods:This cross-sectional and controlled study was performed at a single center between 2018 and 2019. The study population consisted of 44 patients with celiac disease who had been on a gluten-free diet for at least one year.Results:We compared celiac patients with a healthy group. While the celiac patients had significantly higher carotid intima media thickness and carotid pulse wave velocity values, there was no difference in the augmentation index values. There was no significant difference in carotid artery intimal medial thickness, augmentation index and carotid pulse wave velocity values between the diet-compliant and non-compliant groups.Conclusion:Although hypertension was not detected, arterial stiffness and carotid intima media thickness measurements were higher in the celiac disease patients compared to the healthy controls. This showed that these parameters can be used in early vascular damage assessment. These measurements, which are non-invasive and repeatable, can be a guide for the monitoring of the development of preclinical atherosclerosis in the follow-up of the pediatric patients diagnosed with celiac disease.

Despite the widespread use of classical cholesterol-lowering drugs to mitigate the adverse impacts of dyslipidaemia on atherosclerosis, many patients still face a substantial residual risk of developing atherosclerotic cardiovascular disease (CVD). This risk is partially attributed to non-traditional pathophysiological pathways. Latest evidence suggests that sodium glucose co-transporter-2 (SGLT2) inhibitors are beneficial for patients suffering from type 2 diabetes mellitus (T2DM) or established CVD by reducing morbidity and mortality. However, the underlying mechanisms of this benefit have not been clearly elucidated. It has been hypothesized that one possible mechanism could be the attenuation of subclinical atherosclerosis (SA) progression. The objective of this narrative review is to examine the present evidence concerning the impact of SGLT2 inhibitors on markers of SA. The current evidence on the efficacy of SGLT2 on SA, endothelial function and arterial stiffness remains controversial. Findings from observational and randomized studies are quite heterogeneous; however, they converge that the antiatherosclerotic activity of SGLT2 inhibitors is not strong enough to be widely used for prevention of atherosclerosis progression in patients with or without T2DM. Further research is needed to investigate the underlying mechanisms and the possible beneficial impact of SGLT2i on primary and secondary CVD prevention through attenuation of premature atherosclerosis progression. [ABSTRACT FROM AUTHOR]

Atherosclerosis is a key risk factor for developing cardiovascular diseases (CVDs). Flow-mediated dilation (FMD), which reflects vascular reactivity, as well as pulse wave velocity (PWV) and augmentation index (AIx), both markers of arterial stiffness, have emerged as noninvasive, subclinical atherosclerotic markers for the early stages of altered vascular function. In addition to the long-term effects of diet, postprandial processes have been identified as important determinants of CVD risk, and evidence suggests an acute effect of fat quantity and fatty acid (FA) composition on vascular function. However, robust analyses of this association are lacking, especially concerning parameters of arterial stiffness. Therefore, we carried out a systematic literature search in PubMed, Scopus, and the Cochrane Library to investigate the impact of fat quantity and FA composition of meals on postprandial vascular function. Postprandial studies measuring FMD, PWV, and/or AIx in healthy adults and subjects with increased CVD risk (e.g., those with hypercholesterolemia or metabolic syndrome) were analyzed. In total, 24 articles were included; 9 studies focused on the effect of high-fat meals compared with control; and 15 studies investigated the effects of different fat sources. We found that consumption of a high-fat meal causes a reduction in FMD (decrease in vasodilation) and AIx (decrease in arterial stiffness). For eicosapentaenoic acid/docosahexaenoic acid (from fish oil), postprandial assessment (FMD and AIx) indicates a beneficial effect on vascular function. There is limited evidence of an influence of CVD risk on the vascular response to meals with varying fat doses or FA composition. However, meaningful conclusions were difficult to draw because of the large heterogeneity of the studies. Inconsistent results regarding both the impact of fat dose and FA composition on postprandial vascular function should be noted. We propose standardized methods for postprandial protocols to improve data quality in future studies. [ABSTRACT FROM AUTHOR]

• GNSS-PWV time series are computed using 44 GNSS stations in Andalucía and ERA5 temperature and pressure data. • GNSS-PWV and ERA5-PWV are used to compute SPCI time series. • The SPCI generally shows high correlation with the SPEI, with better results for ERA5-SPCI than GNSS-SPCI. • The SPCI outperforms SPI for a limited geographical region and 24-month timescale. In this paper the Standardized Precipitation Conversion Index (SPCI), a PWV-based drought index, has been computed using GNSS and ERA5 PWV and its performance has been tested with respect to the Standardized Precipitation Evapotranspiration Index (SPEI) in Southern Spain. One of the climatic features of this area is the low correlation level between PWV and precipitation, in contrast with other areas in which SPCI has been previously tested. The GNSS-SPCI has been derived from validated ZTD time series estimated from local GNSS permanent stations' data. All the needed meteorological values were derived from ERA5, excepting precipitation values and SPEI-SPI values which were extracted from a national high-resolution dataset. The resulting SPCI time series have shown high correlation coefficients with respect to the SPEI. The use of longer SPCI time series allowed by ERA5 model has provided the most coherent results, suggesting that the ERA5-PWV data can be interesting to overcome problems caused by the short timespan of GNSS time series in SPCI computation. In general, high correlation coefficients have been obtained compared to global results from previous studies. This shows that, even for regions with low correlation levels between PWV and precipitation, the SPCI can have an interesting potential for drought monitoring. The SPCI was found to perform better on higher timescales (12 and 24 months). The performance of SPCI has also been compared that of the SPI: SPCI is able to outperform SPI for the 24-month timescale for a limited geographical region. This supports that the inclusion of PWV data in drought monitoring indices could be promising and is worth keeping to be investigated. [ABSTRACT FROM AUTHOR]

Precipitable water vapor (PWV) from Global Navigation Satellite System (GNSS) offers the benefits of high spatiotemporal resolution logging-consistency and all-weather operability. Estimation of water vapor weighted mean temperature (T m) is a crucial part and a major error source in extracting GNSS PWV from atmospheric delay. Empirical modelling of T m is a convenient approach, especially in cases where, the meteorology community suffers from inefficient and inconsistent logging of temperature and humidity profiles etc., in the existing meteorological observing systems, particularly for harsh weather conditions. In a first, a novel site specific model (T m-SSM) is developed for the atmospheric weighted mean temperature (T m) for 13 CORS (continuously operating reference stations) in the Survey of India (SOI) network, recently established in the hilly state of Uttarakhand (UK) using the ERA5 reanalysis data from 2016 to 2018. GNSS observations at 10 CORS are then used to observe the spatiotemporal characteristics of PWV from T m-SSM during the heavy rainfall event in October 2021. The newly developed T m-SSM performs better with the mean bias error (MBE) and root mean square error (RMSE) of 0.498 and 2.9 K, respectively, when compared with other globally accepted models. The T m-SSM PWV estimates are well correlated with the precipitation data from AWS stations. The newly developed T m-SSM is well conditioned and highly stable, with the mean stability indicator value as low as 1.043%. Further, a close relationship can be observed from the spatiotemporal characteristics of GNSS PWV during heavy rainfall event, with the in-situ precipitation measurements. It is apparent from the results that PWV steadily builds up before the arrival of rain, with sharp peaks in PWV observed just before rainfall event. It then, follows a downward slope through which it decreases to a stable value of around 30 mm when the rainfall ceases. The fluctuations in the PWV from T m-SSM and the passage of the severe mesoscale convective system in a complex terrain such as UK were shown to have high spatial and temporal correlation, which is significant for the monitoring and forecasting such extreme weather. The findings imply that GNSS PWV represents the compendious signature of the water vapor dynamics during severe weather, demonstrating the potential to improve the early detection and sensing of severe weather. [ABSTRACT FROM AUTHOR]

Precipitable water vapor (PWV) with high precision and high temporal resolution estimated by Global Navigation Satellite System (GNSS) is widely used in atmospheric research and weather forecasting. However, most previous works are not consensual concerning the characteristics of the PWV at different time scales and the identification of active and break spells during summ er monsoon climate in Guangxi, China. Taking radiosonde (RS) observations as reference, a strong correlation (R > 0.97) exists between GNSS PWV and RS PWV with a mean root mean square error (RMSE) of 2.68 mm. The annual, seasonal, monthly, and diurnal PWV variations of three years (2017, 2018 and 2020) over Guangxi in were comprehensively investigated using 104 GNSS stations and the fifth-generation European Centre for Medium-Range Weather Forecasts (ECMWF) Atmospheric Reanalysis (ERA5). The mean annual bias and RMSE between GNSS PWV and ERA5 PWV are −1.04 mm and 2.63 mm, respectively. The monthly bias and RMSE range are −0.77 to 3.87 mm, 1.32 to 4.45 mm, and the daily range is −1.41 to 1.07 mm and 1.11 to 5.02 mm, respectively. Additionally, the adopted average standardized rainfall anomaly criteria also identified 7/7/3 active spells and 5/3/7 break spells during the summer monsoon (June–September) from 2017 to 2020, respectively. During the three-year period, the daily amplitude ranges for active spells varied from 1.41 to 2.49 mm, 0.69 to 5.4 mm, and 0.88 to 1.41 mm, while the ranges for break spells were 2.45 to 6.76 mm, 1.66 to 8.17 mm, and 1.48 to 2.99 mm, respectively. The results show a superior performance of GNSS PWV compared to ERA5 PWV in Guangxi, and the maximum, minimum and occurrence time of PWV anomaly vary slightly with the season and the topography of stations. Despite temperature primarily exhibiting a negative correlation with rainfall, acting as a dampener, a positive correlation remains evident between PWV and rainfall. Therefore, densely distributed GNSS stations exhibit excellent capabilities in quantifying atmospheric water vapor and facilitating real-time monitoring of small and medium-scale weather phenomena. [ABSTRACT FROM AUTHOR]

The real‐time high precision of Precipitable Water Vapor (PWV) is widely recognized as crucial for advancing numerical weather prediction and enhancing our understanding of climate change. PWV is usually measured with radiosondes, microwave radiometers, and meteorological satellites. Nevertheless, these instruments have limitations including low temporal or spatial resolutions, high cost and weather dependence. To address these issues, we developed a real‐time PWV grid model for China by integrating the ground‐based Global Navigation Satellite System (GNSS) network with ERA5 reanalysis products. In this study, we explored an alternative method using ERA5 products to construct an accurate Elevation Normalization Factor Model (ENFM) and Tm models. The culmination of our efforts resulted in the creation of a real‐time 1° × 1° PWV grid model for China. To validate the models of Tm and PWV, we compared them against the data obtained from radiosondes in China throughout 2021. The results indicate that the root‐mean‐square error (RMSE) value of the deviation between the Tm derived from our new Tm model, excluding meteorological parameters, and the radiosonde‐derived Tm, is better than 4.22 K. The Tm values of the new Tm model are improved by 15.31% compared to those estimated based on the Bevis model plus HGPT2 temperature model. The RMSE values of the deviations between the new grid PWV and the radiosonde‐derived PWV are less than 3.45 mm. The precision of our new PWV grid model is improved by 37.2% compared to that of the traditional Askne and Nordius model. [ABSTRACT FROM AUTHOR]

Background: Arterial stiffness measurement still plays a role in prediction of future cardiovascular events, thus helping for quantification of patients' cardiovascular (CV) risk level. However, significant measurement difficulties still exist, making its widespread evaluation not routinary. At present indices of arterial stiffness have not been associated with qualitative morphological characteristics of intima-media complex. The intima-media thickness (IMT) measurement is no longer recommended in the cardiovascular disease (CVD) risk assessment due to lack of a standard acquisition protocol. The intima media gray scale median (IM-GSM) is a relatively simple measurement, acquirable during a conventional carotid color-Doppler ultrasound examination. This study aims at investigating the possible relationship between arterial stiffness and echogenicity of IM-GSM of the common carotid arteries, in patients already diagnosed with arterial hypertension. Material and methods: A total of 421 hypertensive patients were retrospectively selected from our database of hypertension outpatients ambulatory. They were divided into two groups according to IM-GSM values (cutoff value: 30) and then subsequently compared. Results: In our study population, subjects with IM-GSM > 30 showed a statistically increased arterial stiffness and left ventricle mass index. A weak positive correlation was also found between IM-GSM, systolic blood pressure and duration of hypertension. Conclusion: The data presented here indicated that the variation of arterial stiffness observed in hypertensive patients is associated with structural modifications in carotid arterial wall. [ABSTRACT FROM AUTHOR]

AbstractBackground Despite the widespread use of classical cholesterol-lowering drugs to mitigate the adverse impacts of dyslipidaemia on atherosclerosis, many patients still face a substantial residual risk of developing atherosclerotic cardiovascular disease (CVD). This risk is partially attributed to non-traditional pathophysiological pathways. Latest evidence suggests that sodium glucose co-transporter-2 (SGLT2) inhibitors are beneficial for patients suffering from type 2 diabetes mellitus (T2DM) or established CVD by reducing morbidity and mortality. However, the underlying mechanisms of this benefit have not been clearly elucidated. It has been hypothesized that one possible mechanism could be the attenuation of subclinical atherosclerosis (SA) progression.Aim The objective of this narrative review is to examine the present evidence concerning the impact of SGLT2 inhibitors on markers of SA.Results The current evidence on the efficacy of SGLT2 on SA, endothelial function and arterial stiffness remains controversial. Findings from observational and randomized studies are quite heterogeneous; however, they converge that the antiatherosclerotic activity of SGLT2 inhibitors is not strong enough to be widely used for prevention of atherosclerosis progression in patients with or without T2DM.Conclusions Further research is needed to investigate the underlying mechanisms and the possible beneficial impact of SGLT2i on primary and secondary CVD prevention through attenuation of premature atherosclerosis progression.

Global navigation satellite system (GNSS) meteorology is utilized in predicting and monitoring extreme weather events using tropospheric products like precipitable water vapour for horizontal 2D detail and water vapour density profiles for 3D detail. In water vapour (WV) tomography, the slant delays from GNSS observations are used to model 4D variations of wet refractivity in the atmosphere above the study area. We present a comprehensive review on the evolution of GNSS WV tomography since its inception, the current state of the art, the challenges faced by the meteorology community, and a qualitative analysis of various techniques used in the process. With the growing infrastructure of meteorologically oriented GNSS station networks as well as increasing utilization of multi-source earth observation datasets powered with machine learning tools, GNSS tomography has shown improvements in producing accurate WV profiles. These new improvements have created the need for conducting multi-factor canonical analyses to understand the efficiency of these well-established methods in controlling the accuracy of the output field. [ABSTRACT FROM AUTHOR]