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INTRODUCTION: The bidirectional relationship between the brain cortex and cardiovascular diseases (CVDs) remains inadequately explored. METHODS: This study used bidirectional Mendelian randomization (MR) analysis to explore the interactions between nine phenotypes associated with hypertension, heart failure, atrial fibrillation (AF), and coronary heart disease (CHD), and brain cortex measurements. These measurements included total surface area (SA), average thickness (TH), and the SA and TH of 34 regions defined by the Desikan-Killiany atlas. The nine traits were obtained from sources such as the UK Biobank and FinnGen, etc., while MRI-derived traits of cortical structure were sourced from the ENIGMA Consortium. The primary estimate was obtained using the inverse-variance weighted approach. A false discovery rate adjustment was applied to the p-values (resulting in q-values) in the analyses of regional cortical structures. RESULTS: A total of 1,260 two-sample MR analyses were conducted. Existing CHD demonstrated an influence on the SA of the banks of the superior temporal sulcus (bankssts) (q=0.018) and the superior frontal lobe (q=0.018), while hypertension was associated with changes in the TH of the lateral occipital region (q=0.02). Regarding the effects of the brain cortex on CVD incidence, total SA was significantly associated with the risk of CHD. Additionally, 16 and 3 regions exhibited significant effects on blood pressure and AF risk, respectively (q<0.05). These regions were primarily located in the frontal, temporal, and cingulate areas, which are associated with cognitive function and mood regulation. CONCLUSION: The detection of cortical changes through MRI could aid in screening for potential neuropsychiatric disorders in individuals with established CVD. Moreover, abnormalities in cortical structure may predict future CVD risk, offering new insights for prevention and treatment strategies.

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BACKGROUND: The accurate selection of patients likely to respond to renal denervation (RDN) is crucial for optimizing treatment outcomes in patients with hypertension. This systematic review was designed to evaluate patient-specific factors predicting the RDN response. METHODS AND RESULTS: We focused on individuals with hypertension who underwent RDN. Patients were categorized based on their baseline characteristics. The primary outcome was blood pressure (BP) reduction after RDN. Both randomized controlled trials and nonrandomized studies were included. We assessed the risk of bias using corresponding tools and further employed the Grading of Recommendations Assessment, Development, and Evaluation approach to assess the overall quality of evidence. A total of 50 studies were ultimately included in this systematic review, among which 17 studies were for meta-analysis. Higher baseline heart rate and lower pulse wave velocity were shown to be associated with significant antihypertensive efficacy of RDN on 24-hour systolic BP reduction (weighted mean difference, -4.05 [95% CI, -7.33 to -0.77]; weighted mean difference, -7.20 [95% CI, -9.79 to -4.62], respectively). In addition, based on qualitative analysis, higher baseline BP, orthostatic hypertension, impaired baroreflex sensitivity, and several biomarkers are also reported to be associated with significant BP reduction after RDN. CONCLUSIONS: In patients with hypertension treated with the RDN, higher heart rate, and lower pulse wave velocity were associated with significant BP reduction after RDN. Other factors, including higher baseline BP, hypertensive patients with orthostatic hypertension, BP variability, impaired cardiac baroreflex sensitivity, and some biomarkers are also reported to be associated with a better BP response to RDN.

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BACKGROUND: The association of different body components, including lean mass and body fat, with the risk of death in acute coronary syndrome (ACS) patients are unclear. METHODS: We enrolled adults diagnosed with ACS at our center between January 2011 and December 2012 and obtained follow-up outcomes via telephone questionnaires. We used restricted cubic splines (RCS) with the Cox proportional hazards model to analyze the associations between body mass index (BMI), predicted lean mass index (LMI), predicted body fat percentage (BF), and the value of LMI/BF with 10-year mortality. We also examined the secondary outcome of death during hospitalization. RESULTS: During the maximum 10-year follow-up of 1398 patients, 331 deaths (23.6%) occurred, and a U-shaped relationship was found between BMI and death risk (P nonlinearity = 0.03). After adjusting for age and history of diabetes, the overweight group (24 ≤ BMI < 28 kg/m2) had the lowest mortality (HR = 0.53, 95% CI: 0.29-0.99). Predicted LMI and LMI/BF had an inverse linear relationship with a 10-year death risk (P nonlinearity = 0.24 and P nonlinearity = 0.38, respectively), while an increase in BF was associated with increased mortality (P nonlinearity = 0.64). During hospitalization, 31 deaths (2.2%) were recorded, and the associations of the indicators with in-hospital mortality were consistent with the long-term outcome analyses. CONCLUSION: Our study provides new insight into the "obesity paradox" in ACS patients, highlighting the importance of considering body composition heterogeneity. Predicted LMI and BF may serve as useful tools for assessing nutritional status and predicting the prognosis of ACS, based on their linear associations with all-cause mortality.

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BACKGROUND: Marital status is associated with cardiovascular disease (CVD) incidence and overall mortality, yet limited research on this topic in elderly individuals is available. Our aim was to comprehensively assess the impact of marital status and other family factors on CVD incidence and long-term mortality among elderly people. METHODS: Data from the Chinese Longitudinal Healthy Longevity Survey (2002/2005/2008-2018) for participants aged ≥60 years were analysed. A cross-sectional study initially examined the correlation between spouses, offspring, living arrangements, and CVD using logistic regression. Subsequently, a retrospective cohort study investigated the long-term associations of these factors with overall mortality via Kaplan-Meier and Cox regression analyses. RESULTS: The study involved 48 510 subjects (average age: 87 years). The cross-sectional analysis revealed a correlation between living with a spouse and an increased incidence of heart disease (adjusted OR 1.27, 95% CI 1.04-1.55) and cerebrovascular disease/stroke (adjusted OR 1.26, 95% CI 1.11-1.42). According to the retrospective cohort analysis, living with a spouse significantly reduced overall mortality (adjusted HR 0.84, 95% CI 0.80-0.87), irrespective of marital relationship quality. Conversely, living with offspring (adjusted HR 1.12, 95% CI 1.08-1.16), having more children (adjusted Pnonlinearity = 0.427) or cohabitants (adjusted Pnonlinearity < 0.0001) were associated with increased overall mortality. CONCLUSION: In the elderly population, being married and living with a spouse were not significantly associated with a decrease in CVD incidence but were associated with a reduction in long-term overall mortality. Living with offspring, having more children, or having a larger family size did not replicate the protective effect but indicated greater overall mortality.

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BACKGROUND AND AIMS: The clinical effects of multivessel interventions in patients with unstable angina/non-ST-segment elevation myocardial infarction (UA/NSTEMI), multivessel disease (MVD) and chronic kidney disease (CKD) remain uncertain. This study aimed to investigate the safety and effectiveness of intervention in non-culprit lession(s) among this cohort. METHODS: We consecutively included patients diagnosed with UA/NSTEMI, MVD and CKD between January 2008 and December 2018 at our centre. After successful percutaneous coronary intervention (PCI), we compared 48-month overall mortality between those undergoing multivessel PCI (MV-PCI) through a single-procedure or staged-procedure approach and culprit vessel-only PCI (CV-PCI) after 1:1 propensity score matching. We conducted stratified analyses and tests for interaction to investigate the modifying effects of critical covariates. Additionally, we recorded the incidence of contrast-induced nephropathy (CIN) to assess the perioperative safety of the two treatment strategies. RESULTS: Of the 749 eligible patients, 271 pairs were successfully matched. Those undergoing MV-PCI had reduced all-cause mortality (hazard ratio (HR): 0.67, 95% confidence interval (CI): 0.48-0.67). Subgroup analysis showed that those with advanced CKD (estimated glomerular filtration rate (eGFR) ≤ 30 mL/min/1.73 m2 ) could not benefit from MV-PCI (P = 0.250), and the survival advantage also tended to diminish in diabetes (P interaction < 0.01; HR = 0.95, 95% CI = 0.65-1.45). Although the staged-procedure approach (N = 157) failed to bring additional survival benefits compared to single-procedure MV-PCI (N = 290) (P = 0.460), it showed a tendency to decrease the death risk. CIN risks in MV-PCI and CV-PCI groups were not significantly different (risk ratio = 1.60, 95% CI = 0.94-2.73). CONCLUSION: Among patients with UA/NSTEMI and non-diabetic CKD and an eGFR > 30 mL/min/1.73 m2 , MV-PCI was associated with a reduced risk of long-term death but did not increase the incidence of CIN during the management of MVD compared to CV-PCI. And staged procedures might be a preferable option over single-procedure MV-PCI.

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Molecular behavior of rhamnolipid mixed with a biobased zwitterionic surfactant at an n-hexadecane/water interface has been studied, and the effects of a rhamnose moiety and composition are evaluated. Results showed that rhamnolipid abundantly interacts with biobased surfactant EAB by means of hydrophobic interactions between aliphatic tails and electrostatic interactions between headgroups, including the attractive interaction between COO- of rhamnolipids and N+ of biobased surfactants and the repulsive interaction between COO- of both surfactants. Dirhamnolipid has a larger number of bound Na+ and a more stable bound structure of COO- ∼ Na+, which screens the repulsive interaction between two kinds of surfactants and shows a more homogeneous distribution with biobased surfactants. The interfacial tension between n-hexadecane and water has been synergistically reduced by dirhamnolipids mixed with biobased surfactants at a higher molar ratio of biobased surfactants. Monorhamnolipids show a strengthened interaction with N+ of biobased surfactants and a more stable hydrogen bond with water relative to that of dirhamnolipids, and there is no synergistic effect in lowering the interfacial tension for the mixture of monorhamnolipids and biobased surfactants. The present work provides details of the molecular behavior of biosurfactant rhamnolipids mixed with biobased surfactants and obtains the key factor in affecting the interfacial properties of the binary system.

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BACKGROUND: The effects of allopurinol in patients with cardiovascular disease are not well defined; therefore, the latest evidence is summarized in this study. METHODS: PubMed, Embase, Cochrane Library, and ClinicalTrials.gov databases were searched for randomized controlled trials (RCTs) of allopurinol in patients with cardiovascular disease published up to 11 February 2023. The primary outcome was cardiovascular death. RESULTS: We combined the results of 21 RCTs that included 22,806 patients. Compared to placebo/usual care, allopurinol treatment was not associated with a significant reduction in cardiovascular death (RR 0.60; 95% CI 0.33-1.11) or all-cause death (RR 0.90; 95% CI 0.72-1.12). However, evidence from earlier trials and studies with small sample sizes indicated that allopurinol might confer a protective effect in decreasing cardiovascular death (RR 0.34; 95% CI 0.15-0.76) across patients undergoing coronary artery bypass grafting (CABG) or having acute coronary syndrome (ACS). In comparisons between allopurinol and febuxostat, we observed no difference in cardiovascular death (RR 0.92; 95% CI 0.69-1.24) or all-cause death (RR 1.02; 95% CI 0.75-1.38). CONCLUSION: Allopurinol could not reduce cardiovascular (CV) death or major adverse CV outcomes significantly in patients with existing cardiovascular diseases. Given the limitations of the original studies, the potential advantages of allopurinol observed in patients undergoing CABG or presenting with ACS necessitate further confirmation through subsequent RCTs. In the comparisons between allopurinol and febuxostat, our analysis failed to uncover any marked superiority of allopurinol in reducing the risk of adverse cardiovascular incidents.

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The purpose of this study is to clarify the difference in oil production rules of conglomerate reservoirs with different pore structures during surfactant-polymer (SP) binary flooding and to ensure the efficient development of conglomerate reservoirs. In this paper, the full-diameter natural cores from the conglomerate reservoir of the Triassic Kexia Formation in the seventh middle block of the Karamay Oilfield (Xinjiang, China) are selected as the research objects. Two schemes of single constant viscosity (SCV) and echelon viscosity reducing (EVR) are designed to displace oil from three main oil-bearing lithologies, namely fine conglomerate, glutenite, and sandstone. Through comprehensive analysis of parameters, such as oil recovery rate, water content, and injection pressure difference, the influence of lithology on the enhanced oil recovery (EOR) of the EVR scheme is determined, which in turn reveals the differences in the step-wise oil production rules of the three lithologies. The experimental results show that for the three lithological reservoirs, the oil displacement effect of the EVR scheme is better than that of the SCV scheme, and the differences in recovery rates between the two schemes are 9.91% for the fine conglomerate, 6.77% for glutenite, and 6.69% for sandstone. By reducing the molecular weight and viscosity of the SP binary system, the SCV scheme achieves the reconstruction of the pressure field and the redistribution of seepage paths of chemical micelles with different sizes, thus, achieving the step-wise production of crude oil in different scale pore throats and enhancing the overall recovery of the reservoir. The sedimentary environment and diagenesis of the three types of lithologies differ greatly, resulting in diverse microscopic pore structures and differential seepage paths and displace rules of SP binary solutions, ultimately leading to large differences in the enhanced oil recoveries of different lithologies. The fine conglomerate reservoir has the strongest anisotropy, the worst pore throat connectivity, and the lowest water flooding recovery rate. Since the fine conglomerate reservoir has the strongest anisotropy, the worst pore throats connectivity, and the lowest water flooding recovery, the EVR scheme shows a good "water control and oil enhancement" development feature and the best step-wise oil production effect. The oil recovery rate of the two schemes for fine conglomerate shows a difference of 10.14%, followed by 6.36% for glutenite and 5.10% for sandstone. In addition, the EOR of fine conglomerate maintains a high upward trend throughout the chemical flooding, indicating that the swept volume of small pore throats gradually expands and the producing degree of the remaining oil in it gradually increases. Therefore, the fine conglomerate is the most suitable lithology for the SCV scheme among the three lithologies of the conglomerate reservoirs.

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Nuclear magnetic resonance (NMR) measurements are performed with the pulse sequence and acquisition parameters set by the operator, which cannot be adjusted in real time according to sample characteristics. In one acquisition cycle, usually thousands of high-power pulses are transmitted and thousands of echo points are acquired. The power consumption cause the RF amplifier to overheat, and large amounts of acquired data may be invalid. Therefore, the optimization of excitation and acquisition processes is necessary to improve measurement efficiency. We explore a scheme for the real-time measurement of the samples by adaptively regulating the pulse sequence, which adapts the variable TE pulse sequence as the reconnaissance mode. The appropriate pulse sequence and reasonable parameters (NE, TE) can be selected according to the relaxation characteristics of the samples.This adaptive control strategy has great significance in guiding both dynamic and static measurements, and it is especially suitable for occasions where low magnetic field gradients and diffusion terms can be ignored. We also design a test circuit for adaptive control, which has the function of automatic parameter adjustment. By adjusting parameters such as the number of refocusing pulses, echo spacing, etc., the effective measurement of the samples can be achieved in practice.

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Nuclear magnetic resonance (NMR) is a powerful tool for formation evaluation in the oil industry to determine parameters, such as pore structure, fluid saturation, and permeability of porous materials, which are critical to reservoir engineering. The inversion of the measured relaxation data is an ill-posed problem and may lead to deviations of inversion results, which may degrade the accuracy of further data analysis and evaluation. This paper proposes a deep learning method for multi-exponential inversion of NMR relaxation data to improve accuracy. Simulated NMR data are first constructed using a priori knowledge based on the signal parameters and Gaussian distribution. These data are then used to train the neural network designed to consider noise characteristics, signal decay characteristics, signal energy variations, and non-negative features of the T2 spectra. With the validation from simulated data, the models introduced by multi-scale convolutional neural network (CNN) and attention mechanism outperform other approaches in terms of denoising and T2 inversion. Finally, NMR measurements of rock cores are used to compare the effectiveness of the attention multi-scale convolutional neural network (ATT-CNN) model in practical applications. The results demonstrate that the proposed method based on deep learning has better performance than the regularization method.

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Background: The prognosis of patients with acute coronary syndrome (ACS) varies greatly, and risk assessment models can help clinicians to identify and manage high-risk patients. While the Global Registry of Acute Coronary Events (GRACE) model is widely used, the clinical pathways for acute coronary syndromes (CPACS), which was constructed based on the Chinese population, and acute coronary treatment and intervention outcomes network (ACTION) have not yet been validated in the Chinese population. Methods: Patients with ACS who underwent coronary angiography or percutaneous coronary intervention from 2011 to 2020, were retrospectively recruited and the appropriate corresponding clinical indicators was obtained. The primary endpoint was in-hospital mortality. The performance of the GRACE, GRACE 2.0, ACTION, thrombolysis in myocardial infarction (TIMI) and CPACS risk models was evaluated and compared. Results: A total of 19,237 patients with ACS were included. Overall, in-hospital mortality was 2.2%. ACTION showed the highest accuracy in predicting discriminated risk (c-index 0.945, 95% confidence interval [CI] 0.922-0.955), but the calibration was not satisfactory. GRACE and GRACE 2.0 did not significantly differ in discrimination (p = 0.1480). GRACE showed the most accurate calibration in all patients and in the subgroup analysis of all models. CPACS (c-index 0.841, 95% CI 0.821-0.861) and TIMI (c-index 0.811, 95% CI 0.787-0.835) did not outperform (c-index 0.926, 95% CI 0.911-0.940). Conclusions: In contemporary Chinese ACS patients, the ACTION risk model's calibration is not satisfactory, although outperformed the gold standard GRACE model in predicting hospital mortality. The CPACS model developed for Chinese patients did not show better predictive performance than the GRACE model.

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Background: Total arterial revascularization (TAR) has gradually become accepted and recognized, but its effect and safety in diabetic patients are not clear. We performed a systematic review and meta-analysis to summarize the safety and efficacy of TAR and additionally evaluated the clinical outcomes of arterial revascularization using different arterial deployments in patients with diabetes. Methods: PubMed, Embase, and the Cochrane Library databases from inception to July 2022 for studies that studied the effect of arterial revascularization in diabetic patients undergoing isolated coronary artery bypass graft (CABG) were searched. The primary outcome was long-term ( ≥ 12 months of follow-up) death by any cause. The secondary efficacy endpoints were long-term ( ≥ 12 months) cardiovascular death, early sternal wound infection (SWI) and death ( ≤ 30 days or in hospital). Risk ratios (RRs), hazard ratios (HRs), and their corresponding 95% confidence intervals (CIs) were calculated to describe short-term results and long-term survival outcomes. Two different ways were used to analyze the effect of TAR and the impact of diabetes on the clinical outcomes of TAR. Results: Thirty-five studies were included in the study, covering 178,274 diabetic patients. Compared to conventional surgery with saphenous veins, TAR was not associated with increased early mortality (RR 0.77, 95% CI 0.48-1.23) and risk of SWI (RR 0.77, 95% CI 0.46-1.28). The overall Kaplan-Meier survival curves based on reconstructed patient data indicated a significant association between TAR and reduced late mortality (HR 0.52, 95% CI 0.48-0.67) and the curves based on the propensity-score matched (PSM) analyses suggested a similar result (HR 0.74, 95% CI 0.66-0.85). TAR could also effectively decrease the risk of cardiovascular death (HR 0.42, 95% CI 0.24-0.75). Through comparing the effect of TAR in patients with and without diabetes, we found that the presence of diabetes did not elevate the risk of early adverse events (death: RR 1.50, 95% CI 0.64-3.49; SWI: RR 2.52, 95% CI 0.91-7.00). Although diabetes increased long-term mortality (HR 1.06; 95% CI 1.35-2.03), the cardiovascular death rate was similar in patients with diabetes and patients without diabetes (HR 1.09; 95% CI 0.49-2.45). Regarding the selection of arterial conduits, grafting via the bilateral internal mammary artery (BIMA) decreased the risk of overall death (HR 0.67, 95% CI 0.52-0.85) and cardiovascular death (HR 0.55, 95% CI 0.35-0.87) without resulting in a significantly elevated rate of early death (RR 0.95, 95% CI 0.82-1.11). However, the evidence from PSM studies indicated no difference between the long-term mortality of the BIMA group and that of the single internal mammary arteries (SIMA) groups (HR 0.76, 95% CI 0.52-1.11), and the risk of SWI was significantly increased by BIMA in diabetes (RR 1.65, 95% CI 1.42-1.91). The sub-analysis indicated the consistent benefit of the radial artery (RA) application in diabetic patients (HR 0.71, 95% CI 0.63-0.79) compared to saphenous vein graft. In two propensity-score-matched studies, the evidence showed that the survival outcomes of the BIMA group were similar to that of the SIMA plus RA group but that grafting via the RA reduced the risk of sternal wound infection. Conclusions: Compared with conventional surgery using SVG, TAR was associated with an enhanced survival benefit in diabetes and this long-term gain did not increase the risk of early mortality or SWI. Given the increased infection risk and controversial long-term survival gains of grafting via the BIMA in diabetes, its wide use for grafting in this cohort should be seriously considered. Compared to using the right internal mammary artery (RIMA), RA might be a similarly effective but safer option for patients with diabetes.

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HYPOTHESIS: It is generally believed that the improved efficiency of surfactant enhanced oil recovery (EOR) comes from ultra-low interfacial tension (IFT) between oil and surfactant solution owing to the formation of middle-phase microemulsion. However, hindered visibility in underground porous media prevents direct observation of in situ generation of middle-phase microemulsion during surfactant flooding. Thus, direct visualization of the process is vital, and could clarify its contribution to EOR. EXPERIMENTS: Micro-emulsification of a displacing fluid containing sodium 4-dodecylbenzenesulfonate and alcohol propoxy sulfate with model oil was investigated. Phase diagrams were drawn using salinity scans, and the influence of polymer on emulsification was analyzed. Micro-emulsification was monitored through in situ fluorescent tagging via 2D-microfluidics and ex situ visualization via cryo-electron microscopy and small angle X-ray scattering. Its contribution to the oil recovery factor was quantified by measuring the volume of each phase in the eluates. FINDINGS: On-chip experiments indicated that in situ micro-emulsification occurred when the prescreened surfactant solution flowed in contact with trapped oil. The aqueous phase initially invaded the residual oil, forming a low mobility microemulsion. This microemulsion was then diluted by subsequent displacing fluid, forming a new driving fluid that caused ultra-low IFT in the trapped oil downstream. Under the synergistic effect of micellar solubilization and trapped-oil mobilization, the recovery factor could be increased by up to 40% over waterflooding and 43% on polymer inclusion in the formulation.

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BACKGROUND AND AIMS: The benefits and safety of antidyslipidemia pharmacotherapy in patients with chronic kidney disease were not well defined so the latest evidence was summarized by this work. METHODS: This systematic review and Bayesian network meta-analysis (NMA) included searches of PubMed, Embase, and Cochrane Library from inception to 28 February 2022, for randomized controlled trials of any antilipidaemic medications administered to adults with chronic kidney disease [CKD: defined as estimated glomerular filtration rate (eGFR) ≤ 60 mL/min/1.73 m2 not undergoing transplantation], using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool to assess the certainty of the evidence. RESULTS: 55 trials and 30 works of them were included in our systematic review and NMA, respectively. In comparisons with no antidyslipidemia therapy or placebo, proprotein convertase subtilisin/Kexin type 9 inhibitors plus statin (PS) was the most effective drug regimen for reducing all-cause mortality (OR 0.62, 95% CI [0.40, 0.93]; GRADE: moderate), followed by moderate-high intensity statin (HS, OR 0.76, 95% CI [0.60, 0.93]; I2 = 66.9%; GRADE: moderate). PS, HS, low-moderate statin (LS), ezetimibe plus statin (ES), and fibrates (F) significantly decreased the composite cardiovascular events. The subgroup analysis revealed the null effect of statins on death (OR 0.92, 95% CI [0.81, 1.04]) and composite cardiovascular events (OR 0.94, 95% CI [0.82, 1.07]) in dialysis patients. CONCLUSION: In nondialysis CKD patients, statin-based therapies could significantly and safely reduce all-cause death and major composite cardiovascular events despite the presence of arteriosclerotic cardiovascular disease and LDL-c levels. Aggressive medication regimens, PS and HS, appeared to be more effective, especially in patients with established CAD.

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Petroleum cokes with different chemical structures and oxygen-containing functional groups were obtained from two kinds of naphthenic- and paraffin-base crude oils by simulating an in situ combustion (ISC) process with the same reaction atmosphere and different reaction temperatures. 13C wide-cavity solid-state nuclear magnetic resonance (13C NMR) spectroscopy was used to identify and investigate the oxygen-containing functional groups of petroleum cokes obtained under different compositions and reaction temperatures. This study demonstrated that with the increase of coking temperature, the content of alkyl side chain and active oxygen-containing functional groups in naphthenic-base crude coke decreased obviously, while the content of aromatic carbon increased. The 13C NMR analysis of the two kinds of petroleum cokes obtained at 500 °C further revealed that the paraffin-base petroleum coke retained a high content of oxygen- and nitrogen-rich functional groups, while the naphthenic-base petroleum coke had a lower amount of carbonyl groups and oxygen-containing functional groups.

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The research of borehole nuclear magnetic resonance (NMR) began in the 1950 s, but the maturity and large-scale applications of relevant instruments started in the mid-1990. To date, borehole NMR is an important means for borehole in-situ analysis and oil and gas evaluation, which significantly improves the success rate of exploration and the evaluation accuracy of oil and gas reservoirs. Its development has also contributed importantly to low-field and industrial NMR theories and experimental methodologies. Companies and individuals in the United States, China and other countries have developed the capabilities to engineer and deploy borehole NMR instruments and measurements independently. NMR imaging and evaluation of heterogeneous reservoirs and unconventional oil and gas are worldwide problems, involving the innovation of borehole NMR and the advanced manufacture of instruments and equipment. The commercial technology of borehole oil and gas exploration is highly competitive and proprietary. It is difficult to gain full insight into the details of the technologies and development from published literatures. Based on the research of the author's NMR laboratory at the China University of Petroleum (CUP), this paper reviews the core technologies of borehole NMR and its applications, discusses selected important issues that have not been fully solved, and looks forward to the direction and prospects of future development.

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BACKGROUND: As a strong risk factor for coronary artery disease (CAD), chronic kidney disease (CKD) indicates higher mortality in patients with CAD. However, the optimal treatment for the patients with two coexisting diseases is still not well defined. METHODS: To conduct a meta-analysis, PubMed, Embase, and the Cochrane database were searched for studies comparing medical treatment (MT) and revascularization [percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG)] in adults with CAD and CKD. Long-term all-cause mortality was evaluated, and subgroup analyses were performed. RESULTS: A total of 13 trials met our selection criteria. Long-term (with at least a 1-year follow-up) mortality was significantly lower in the revascularization arm [relative risk (RR) = 0.66; 95% CI = 0.60-0.72] by either PCI (RR = 0.61; 95% CI = 0.55-0.68) or CABG (RR = 0.62; 95% CI = 0.46-0.84). The results were consistent in dialysis patients (RR = 0.68; 95% CI = 0.59-0.79), patients with stable CAD (RR = 0.75; 95% CI = 0.61-0.92), patients with acute coronary syndrome (RR = 0.62; 95% CI = 0.58-0.66), and geriatric patients (RR = 0.57; 95% CI = 0.54-0.61). CONCLUSION: In patients with CKD and CAD, revascularization is more effective in reducing mortality than MT alone. This observed benefit is consistent in patients with stable CAD and elderly patients. However, future randomized controlled trials (RCTs) are required to confirm these findings.

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Nuclear magnetic resonance (NMR) provides useful information for formation evaluation on pore size and pore volume. Depending on field operations, there are two types of borehole NMR: wireline logging and logging-while-drilling (LWD). The latter type is more convenient. But due to the high mechanical failure risk caused by insufficient mechanical strength of the tool and vibrations during measurement, the quality of LWD NMR measurements are severely affected. In this paper, to enable high reliability and vibration tolerance, we propose a new design and implement a new LWD NMR tool, whose features includes a double hollow cylindric magnet (DHCM) structure and a solenoid-optimized antenna. The DHCM structure greatly reduces the proportion of the magnet in the cross-section of the tool without reducing B0 field strength. Thus, the mechanical strength and the reliability of the tool is greatly improved. The antenna is improved by optimizing the parameters of each coil of the solenoid for finding the generated B1 distribution best matching B0. The new design has a saddle sensing area in the axial and radial plane with a width greater than 50 mm, which is wide enough to ensure the validity of the T2 measurement under strong vibrations. We had demonstrated that this new tool performs well when TE = 0.6 ms, ensuring the measurement richness is suitable for LWD prospecting for unconventional oil and gas reservoirs. Besides, this design is suitable for that in slim holes.

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HYPOTHESIS: It is well recognized that crude oil could be emulsified during surfactant flooding process, and recently such an in-situ emulsification was found practically helpful for enhanced oil recovery (EOR). However, no direct proofs are reported yet to unravel how emulsion is formed in porous media and how important to increasing oil recovery factor due to unavailability to visualize the emulsification process, thus it is desirable to verify visibly the formation of emulsion in porous media and the contribution of emulsification to EOR process. EXPERIMENTS: Two types of microfluidic chips with heterogeneous and homogeneous pore geometries respectively were employed to simulate the underground oil reservoir environment. Sodium dodecylbenzenesulfonate (SDBS) was selected as a model surfactant, and its aqueous solution was injected into the paraffin oil-saturated microchip to mimic the displacing process. A series of tests were conducted by varying SDBS concentration, electrolyte content, injection rate, and pore-scale snapshots were captured for qualitative and quantitative analysis of in-situ emulsification during the surfactant flooding. FINDINGS: Both oil-in-water (O/W) and water-in-oil (W/O) emulsions are formed in microchips during the surfactant flooding. Increasing SDBS concentration, migration distance, injection rate, or addition of electrolyte tends to form smaller O/W particles through snapping action at pore throat, and vice versa. Smaller size endows oil with a better mobility to go through the pore throat, and up to 24% extra emulsion can be achieved through emulsification entrainment; bigger droplets can block the dominant paths, thus improving sweep efficiency and increasing oil recovery factor up to 30% compared to waterflooding. Furthermore, W/O emulsification was found to be a time-dependent process influenced by SDBS concentration, and oil was recovered by diffusing surfactant solution into oil phase and replacing the oil-occupied space in porous media.

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Inside-out nuclear magnetic resonance (NMR) is a unique technique for investigating large in-situ objects outside of tools, to provide pore structure and pore-bearing fluids properties. However, in borehole, objects towards azimuthal orientations pose different properties, referred to as azimuthal spatial heterogeneity. This may lead to ambiguous evaluations by utilizing present inside-out NMR measurement, which hardly resolves azimuthal information and loses the location information of oil/gas. In this paper, we for the first time design and construct an innovative tool to investigate the heterogeneity of large in-situ samples. The most key component, array coil, which performs with azimuthal selection, measurement consistency and interactive isolation, configured in this novel tool to capture heterogeneity information. Whereas, strong coupling between neighboring coil elements largely decrease the coil sensitivity. Capacitive decoupling network is bridged into adjacent ports without segmenting coils to be decoupled and could be easily adjusted by electrical relays. The coil model and numerical simulation are firstly given to demonstrate the array coil configuration, B1 field map and mutual coupling effects on coil sensitivity. Capacitive network is then introduced to be theoretically and practically analyzed to minimize coupling effects. Simulation and experimental results demonstrate that these coil elements have excellent consistency and independence to feasibly acquire the azimuthal NMR data.