Hard and Highly Adhesive AlMgB14 Coatings RF Sputtered on Tungsten Carbide and High-Speed Steel.

We report a new industrial application of aluminum magnesium boride AlMgB14 (BAM) coatings to enhance the hardness of tungsten carbide ceramic (WC-Co) and high-speed steel tools. BAM films were deposited by RF magnetron sputtering of a single dense stoichiometric ceramic target onto commercial WC-Co turning inserts and R6M5 steel drill bits. High target sputtering power and sufficiently short target-to-substrate distance were found to be critical processing conditions. Very smooth (6.6 nm RMS surface roughness onto Si wafers) and hard AlMgB14 coatings enhance the hardness of WC-Co inserts and high-speed R6M5 steel by a factor of two and three, respectively. Complete coating spallation failure occurred at a scratch adhesion strength of 18 N. High work of adhesion and low friction coefficient, estimated for BAM onto drill bits, was as high as 64 J/m2 and as low as 0.07, respectively, more than twice the surpass characteristics of N-doped diamond-like carbon (DLC) films deposited onto nitride high-speed W6Mo5Cr4V2 steel.

Printing Parameters of Fused Filament Fabrication Affect Key Properties of Four-Dimensional Printed Shape-Memory Polymers.

Extrusion-based (fused filament fabrication) three-dimensional (3D) printing of shape-memory polymers (SMPs) has the potential to rapidly produce highly customized smart-material parts. Yet, the effects of printing parameters on the shape-memory properties of printed SMPs remain poorly understood. To study the extent to which the 3D printing process affects the shape-memory properties of a printed SMP part, here temperature, extrusion rate multiplier, and fiber orientation were systematically varied, and their effect on shape-memory fixing and recovery ratios was evaluated. Fiber orientation, as determined by print path relative to the direction(s) of loading during shape-memory programming, was found to significantly impact the fixing ratio and the recovery ratio. Temperature and multiplier had little effect on either fixing ratio or recovery ratio. To facilitate the use of printed SMP parts in biomedical applications, a cell viability assay was performed on 3D-printed samples prepared using varied temperature and multiplier. Reduction in multiplier was found to increase cell viability. The results indicate that fiber orientation can critically impact the shape-memory functionality of 3D-printed SMP parts, and that multiplier can affect cytocompatibility of those parts. Thus, researchers and manufacturers employing SMPs in 3D-printed parts and devices could achieve improved part functionality if print paths are designed to align fiber direction with the axis(es) in which strain will be programmed and recovered and if the multiplier is optimized in biomedical applications in which a part will contact cells.

Evaluation of Different Reverse Osmosis Membranes for Textile Dyeing and Finishing Wastewater Reuse.

Different commercial reverse osmosis (RO) membranes from Vontron and DuPont Filmtec were evaluated for textile dyeing and finishing wastewater (TDFW) reuse in China. All six tested RO membranes produced qualified permeate meeting TDFW reuse standards at a water recovery ratio (WRR) of 70% in single batch tests. The rapid decline of apparent specific flux at WRR over 50% was mainly ascribed to feed osmotic pressure increase caused by concentrating effects. Multiple batch tests using Vontron HOR and DuPont Filmtec BW RO membranes with comparable permeability and selectivity demonstrated the reproducibility and showed low fouling development. The occurrence of carbonate scaling on both RO membranes was identified by scanning electron microscopy and energy disperse spectroscopy. No obvious organic fouling was detected on both RO membranes by attenuated total reflectance Fourier transform infrared spectrometry. From the orthogonal tests, with an integrated RO membrane performance index (i.e., 25% rejection ratio of total organic carbon + 25% rejection ratio of conductivity + 50% flux ratio of final to initial) as a target, the optimal parameters were determined as WRR of 60%, cross-flow velocity (CFV) of 1.0 m/s, temperature (T) of 20 °C for both RO membranes, while trans-membrane pressures (TMP) of 2 and 4 MPa were optimal for Vontron HOR RO membrane and DuPont Filmtec BW RO membrane, respectively. Both RO membranes with the optimal parameters produced good permeate quality for TDFW reuse and kept a high flux ratio of final to initial, demonstrating the effectiveness of the orthogonal tests.

Designing a novel poly (methyl vinyl ether maleic anhydride) based polymeric membrane with enhanced antifouling performance for removal of pentachlorophenol from aqueous solution.

In this current study, poly (methyl vinyl ether maleic anhydride) (PMVEAMA), a sustainable additive, was incorporated into poly (ether-ether sulfone) (PEES) polymer to design a novel polymeric hybrid membrane for the efficient filtration of toxic pentachlorophenol (PCP) from an aqueous medium. Hydrophilic additives significantly altered the membrane's morphology, structure, porosity, water content, and flux performance compared to the bare PEES membrane. The influence of PMVEAMA on the structural modification of the synthesized polymer membrane was confirmed by SEM, ATR-FTIR, XRD, AFM, zeta potential and contact angle. Findings revealed that the addition of PMVEAMA to the PEES polymer enhances the porosity (17.7%-28.9%), water content (29.8%-39.8%), and pure water flux (186 Lm-2h-1 to 349 Lm-2h-1). The effect of PMVEAMA concentration on the PEES membrane exhibited more finger like pores, better porosity and hydrophilicity, reduced surface roughness, fouling and increased permeability. The fouling studies exhibit an improved 57% PCP rejection and permeation flux of 22.3 Lm-2h-1 due to the addition of the hydrophilic additive. Surprisingly, the incorporation of PMVEAMA into the bare PEES membrane resulted in a high flux recovery ratio of 73.7%. The antifouling properties and enhanced permeability of the PEES/PMVEAMA membrane indicates its potential application in water purification sectors for the efficient separation of contaminants.

Recovery ratios and minimum clinically important difference for clinical outcomes in workers' compensation recipients undergoing MIS-TLIF versus ALIF.

BACKGROUND: There is a scarcity of literature that examines clinical outcomes through patient-reported outcomes (PROs), minimum clinically important difference (MCID), and recovery ratios (RR) for workers' compensation (WC) recipients undergoing minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) versus anterior lumbar interbody fusion (ALIF). METHODS: WC claimants undergoing MIS-TLIF versus ALIF were propensity score matched to account for demographic differences. Demographics, perioperative characteristics, and PROs were collected. PROs of Patient-Reported Outcomes Measurement Information System Physical Function (PROMIS-PF), 12-Item Short Form Physical Composite Score (SF-12 PCS), Visual Analog Scale (VAS) back, VAS leg, and Oswestry Disability Index (ODI) were collected at preoperative and postoperative time points. MCID achievement was determined through comparison to values in literature. RR was calculated as the difference between postoperative and preoperative PROs over potential improvement. Comparison between surgical techniques was through non-parametric inferential statistics. RESULTS: Eighty-four WC claimants, with 50 patients undergoing MIS-TLIF, were identified after propensity score matching. ALIF patients had higher estimated blood loss. MIS-TLIF patients had higher postoperative day (POD) 0 VAS pain and POD 0 + 1 narcotic consumption. Patients undergoing either MIS-TLIF or ALIF reported significant improvement in pain and disability. ALIF patients reported significant improvement in physical function. ALIF patients reported superior 1-year PROMIS-PF, 6-week SF-12 PCS, 6-month VAS back, and 12-week VAS leg. No significant differences in MCID achievement rates were noted between cohorts. ALIF patients had higher RR in 6-week and 1-year PROMIS-PF and 6-week SF-12 PCS. CONCLUSION: Workers' compensation claimants undergoing either MIS-TLIF or ALIF reported significant improvement in pain and disability. ALIF patients reported superior postoperative physical function and pain. ALIF patients had higher recovery ratios in physical function. Workers' compensation claimants undergoing ALIF may experience greater physical function recovery and superior clinical outcomes in physical function and pain.

Effect of Fiber Reinforcement on Creep and Recovery Behavior of Cement-Emulsified Asphalt Binder.

In order to evaluate and improve the deformation behavior of cement-emulsified asphalt binder (CA) in cement-emulsified asphalt mixture, this study investigated the reinforcement of small additions of fibers (2%, 4%, and 6% addition by mass of cement) on the deformation resistance of CA. A repeated creep recovery test was implemented that measures the recovery rate of creep deformation and accumulated strain. Further, an improved piecewise curve-fitting method was used to determine the parameters of Burgers model, then the creep compliances were fitted and calculated. The results show the repeated creep recovery test to be a suitable method for obtaining useful information about creep and recovery deformation of fiber-reinforced CA. The influence of fiber types and dosages on the deformation recovery ability is determined based on the creep recovery ratio and accumulated strain. The improved piecewise curve-fitting method has high accuracy. Thereafter, the reinforcement effect was analyzed through the evolution of creep compliance under loading. Therefore, this paper can provide a reference for enhancing the properties of cement-emulsified asphalt mixture by maximizing the fiber reinforcement.

Single-Level Minimally Invasive Transforaminal Lumbar Interbody Fusion versus Anterior Lumbar Interbody Fusion with Posterior Instrumentation at L5/S1.

OBJECTIVE: To compare outcomes between minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and anterior lumbar interbody fusion (ALIF) at L5/S1. METHODS: Primary, elective, single, MIS-TLIF, or ALIF with posterior fixation at L5/S1 were identified. Patient-reported outcome measures (PROMs) were collected. Coarsened exact matching was used to control for significant differences. Achievement of minimum clinically important difference [MCID] was determined by comparing ΔPROM scores with threshold values. Demographic/perioperative characteristics were compared between MIS-TLIF and ALIF cohorts using χ2 Student t tests. Differences in mean PROM scores, MCID rates, and postoperative complications were evaluated using an unpaired t test. RESULTS: After coarsened exact matching, 93 patients received MIS-TLIF and 50 received ALIF. Cohorts differed in operative time, estimated blood loss, and postoperative narcotic consumption on postoperative day 0 (P < 0.034, all). Mean PROMs differed significantly on 12-Item Short-Form Physical Component Summary at 6 weeks and 1 year, Patient-Reported Outcomes Measurement Information System Physical Function at 6 weeks, Oswestry Disability Index at 6 weeks, and visual analog scale (VAS) back at 6 weeks, with the ALIF cohort showing significantly improved mean PROMs (P ≤ 0.044, all). Significantly greater rates were reported of MCID achievement for PROMs for the ALIF cohort: VAS back at 6 weeks, Oswestry Disability Index at 12 weeks, 12-Item Short-Form Physical Component Summary at 6 weeks, and Patient-Reported Outcomes Measurement Information System Physical Function at 12 weeks (P ≤ 0.047, all). A greater rate of MCID achievement for the MIS-TLIF cohort was seen for 6-week and overall VAS leg (P < 0.046, all). Postoperative fever was greater in the TLIF cohort (9.6% vs. 2.0%; P < 0.047). CONCLUSIONS: Patients undergoing ALIF showed significantly improved rates of MCID achievement for disability, physical function, and back pain during the early postoperative period. However, the overall MCID achievement rate for leg pain was higher for the MIS-TLIF cohort.

Simulation study of the Lower Cretaceous geothermal reservoir for aquifer thermal energy storage.

The aquifer thermal energy storage (ATES) has gained attention in several countries as an installation for increasing the energy efficiency of geothermal systems and the use of waste heat. The Lower Cretaceous reservoir is known as one of the most prospective for geothermal purposes in Poland. However, in the southern part of the Mogilno-Lódz Trough (Central Poland) is considered to have a lower geothermal potential. The aim of this paper is to study whether the Lower Cretaceous reservoir in this area is suitable for aquifer thermal energy storage. Prior to dynamic simulations in Feflow© software, a regional Petrel© static parametric model which includes a multidisciplinary approach was prepared. A methodology of fitting Petrel's structural and parametrical model to Feflow requirements is provided within this paper. The performance simulation of 4 systems has been conducted for 30 years. Increasing precipitation potential is expected for aragonite and calcite along with a temperature increase, while silica precipitation carries a much smaller risk. The paper presents potential for ATES systems in the Lower Cretaceous reservoir of the study area with the best doublet location having thermal recovery ratio of 0.47 and 0.34 for 30 and 40 K temperature differential scenario. An imbalance in heat injection/production in the storage system can cause the reservoir to cool faster than in conventional geothermal heating installation. ATES can provide a successful geothermal reservoir boosting in the case of applying a balanced injection of waste heat.

Body-Temperature Programmable Soft-Shape Memory Hybrid Sponges for Comfort Fitting.

Porous shape memory hybrids are fabricated with different matrix (silicone) hardness and different inclusion (polycaprolactone, PCL) ratios. They are characterized to obtain their mechanical response to cyclic loads (with/without pre-straining/programming) and their shape memory performances after body-temperature programming are investigated. These materials are lightweight due to their porous structures. Wetted hydrogels used in the fabrication process for creating pores are reusable and hence this process is eco-friendly. These porous shape memory hybrids exhibit the good shape memory effect of around 90% with higher inclusion (PCL) ratios, which is better than the solid versions reported in the literature. Hence, it is concluded that these materials have great potential to be used in, for instance, insoles and soles for comfort fitting, as demonstrated.

Recycling of lead from spent lead-acid battery by vacuum reduction-separation of Pb-Sb alloy coupling technology.

Until today, there are still many problems that must be solved through innovative research to make the recycling of spent lead-acid batteries and the separation of Pb-Sb alloy more environmentally friendly and energy-saving. In this paper, a novel method for regenerating lead paste, by vacuum reduction reaction coupling with separation of Pb-Sb alloy, was developed. In this process, antimony from Pb-Sb alloy is used to reduce desulfurized lead paste into lead under vacuum, while it is oxidized into volatile Sb2O3 as by-product. The results showed that direct recovery ratio of Pb from desulfurized lead paste reached 99.29% and Sb-content in Pb-Sb alloy decreased from 46% to 0.98% under following conditions: the mass ratio of desulfurized lead paste to Pb-Sb alloy of 1.50, residual gas pressure of 30 Pa, reduction temperature of 810 °C for 50 min. By this method, not only the lead paste can be recovered with high atom economy, but also the Pb-Sb alloy can be separated efficiently at zero cost and without "three wastes" generation. Therefore, this method is very useful for the recycling of spent lead-acid battery and the separation of Pb-Sb alloy.

Influence of Long-Term Storage on Shape Memory Performance and Mechanical Behavior of Pre-stretched Commercial Poly(methyl methacrylate) (PMMA).

In this paper, we experimentally investigate the influence of storage at 40 °C on the shape memory performance and mechanical behavior of a pre-stretched commercial poly(methyl methacrylate) (PMMA). This is to simulate the scenario in many applications. Although this is a very important topic in engineering practice, it has rarely been touched upon so far. The shape memory performance is characterized in terms of the shape fixity ratio (after up to one year of storage) and shape recovery ratio (upon heating to previous programming temperature). Programming in the mode of uniaxial tension is carried out at a temperature within the glass transition range to one of four prescribed programming strains (namely 10%, 20%, 40% and 80%). Also investigated is the residual strain after heating for shape recovery. The characterization of the mechanical behavior of programmed samples after storage for up to three months is via cyclic uniaxial tensile test. It is concluded that from an engineering application point view, for this particular PMMA, programming should be done at higher temperatures (i.e., above its Tg of 110 °C) in order to not only achieve reliable and better shape memory performance, but also minimize the influence of storage on the shape memory performance and mechanical behavior of the programmed material. This finding provides a useful guide for engineering applications of shape memory polymers, in particular based on the multiple-shape memory effect, temperature memory effect, and/or low temperature programming.

The state of desalination and brine production: A global outlook.

Rising water demands and diminishing water supplies are exacerbating water scarcity in most world regions. Conventional approaches relying on rainfall and river runoff in water scarce areas are no longer sufficient to meet human demands. Unconventional water resources, such as desalinated water, are expected to play a key role in narrowing the water demand-supply gap. Our synthesis of desalination data suggests that there are 15,906 operational desalination plants producing around 95 million m3/day of desalinated water for human use, of which 48% is produced in the Middle East and North Africa region. A major challenge associated with desalination technologies is the production of a typically hypersaline concentrate (termed 'brine') discharge that requires disposal, which is both costly and associated with negative environmental impacts. Our estimates reveal brine production to be around 142 million m3/day, approximately 50% greater than previous quantifications. Brine production in Saudi Arabia, UAE, Kuwait and Qatar accounts for 55% of the total global share. Improved brine management strategies are required to limit the negative environmental impacts and reduce the economic cost of disposal, thereby stimulating further developments in desalination facilities to safeguard water supplies for current and future generations.

Removal of trace hexavalent chromium from aqueous solutions by ion foam fractionation.

Ion foam fractionation is a green and cost-effective technology where separation of molecules exploits the difference in surface affinity. In this work, a batch ion foam fractionation system was designed and optimized for the separation of trace hexavalent chromium (Cr(VI)) from aqueous solutions. The effect of surfactant head groups (collectors) on the adsorption dynamics was analyzed. Cetyl trimethyl ammonium bromide (CTAB), a cationic surfactant showed high efficiency for the removal of Cr(VI) from aqueous solutions. An experimental investigation of the effect of different operational parameters on the separation characteristics is presented. The recovery of Cr(VI) increased with the increase in CTAB/Cr(VI) molar ratio and reached a maximum of 92.5% at optimum operating conditions. However, with CTAB concentrations close to the critical micelle concentration (CMC) wet foams were produced resulting in high liquid hold-up and poor enrichment ratio. The presence of Cr(VI) at the gas-liquid interface significantly improved the drainage characteristics of the foam decreasing the liquid hold-up. Further, a three-stage ion foam fractionation unit was developed with Cr(VI) removal efficiency of more than 99%. The concentration of Cr(VI) in the residue after the three-stage operation was less than 0.02 mg/L which is below the USEPA recommended standards for drinking water.

Recovery of high-concentration volatile fatty acids from wastewater using an acidogenesis-electrodialysis integrated system.

Recovery of volatile fatty acids (VFAs) from wastewater is an important route for wastewater valorization. Selective acidogenic fermentation enables an efficient production of VFAs from wastewater, whereas electrodialysis (ED) provides an effective approach to concentrate VFAs. However, these two processes have not been coupled in one single system previously. In this study, an acidogenesis-ED integrated system that coupled a continuous acidogenesis with a batch process of VFA concentration was developed for recovery of high-concentration VFAs from wastewater. Under 20.0 V voltage, the acetate was concentrated by 4-fold and the propionate and butyrate were concentrated by over 3-fold in the integrated system after 528-h operation. The declined VFAs recovery ratios at the later stage due to significant reverse diffusion indicate a need to prevent product over-accumulation. This work demonstrated the feasibility of the acidogenesis-ED integrated reactor for wastewater valorization and discussed the remaining challenges and opportunities.

[Recovery of hemoglobin level and blood pressure in workers unfit for duties at high altitude following relocation].

Objective: To determine the hemoglobin level and blood pressure and the factors that influence their recovery in relocated workers who were unfit for duties at high altitude. Methods: The physical examination data of 693 relocated workers who previously worked at high altitude were dynamically monitored from January 2006 to June 2015 in order to examine the recovery of hemoglobin level and blood pressure. Results: The rate of hemoglobin recovery was 81.37% among the 161 relocated workers with abnormal hemoglobin levels, and the rate of blood pressure recovery was 69.51% among the 164 relocated workers with abnormal blood pressure. The rates of hemoglobin and blood pressure recovery were decreased in individuals aged 40 years and older. The peak recovery time of hemoglobin was 11-15 months following relocation, and that of blood pressure was 5-7 months and 11-13 months following relocation. The half-year blood pressure recovery rate and 2-year hemoglobin recovery rate following relocation were significantly higher in workers who worked at 2500-3000 m altitude than in those at ≥3000 m (P<0.05) . Total cholesterol and educational level were factors that influence the half-year blood pressure recovery in relocated workers (P<0.05) . Conclusion: The rate of hemoglobin and blood pressure recovery are high among relocated workers who previously worked at high altitude. Factors that influence blood pressure, such as total cholesterol, should be closely monitored so that high-altitude workers with abnormal blood pressure and hemoglobin level can be relocated as early as possible.

Recovery of hemoglobin level and blood pressure in workers unfit for duties at high altitude following relocation / 中华劳动卫生职业病杂志

Objective@#To determine the hemoglobin level and blood pressure and the factors that influence their recovery in relocated workers who were unfit for duties at high altitude.@*Methods@#The physical examination data of 693 relocated workers who previously worked at high altitude were dynamically monitored from January 2006 to June 2015 in order to examine the recovery of hemoglobin level and blood pressure.@*Results@#The rate of hemoglobin recovery was 81.37% among the 161 relocated workers with abnormal hemoglobin levels, and the rate of blood pressure recovery was 69.51% among the 164 relocated workers with abnormal blood pressure. The rates of hemoglobin and blood pressure recovery were decreased in individuals aged 40 years and older. The peak recovery time of hemoglobin was 11-15 months following relocation, and that of blood pressure was 5-7 months and 11-13 months following relocation. The half-year blood pressure recovery rate and 2-year hemoglobin recovery rate following relocation were significantly higher in workers who worked at 2500-3000 m altitude than in those at ≥3000 m (P<0.05) . Total cholesterol and educational level were factors that influence the half-year blood pressure recovery in relocated workers (P<0.05) .@*Conclusion@#The rate of hemoglobin and blood pressure recovery are high among relocated workers who previously worked at high altitude. Factors that influence blood pressure, such as total cholesterol, should be closely monitored so that high-altitude workers with abnormal blood pressure and hemoglobin level can be relocated as early as possible.

Exposure to sublethal levels of PCB-126 impacts fuel metabolism and swimming performance in rainbow trout.

Polychlorinated biphenyls (PCBs) are recognized physiological stressors to fish which over time may impair individual performance and perhaps fitness by inducing changes that could have population-level consequences. PCB-126 (3,3',4,4',5-pentachlorobiphenyl) accumulates in lipids and can subsequently be released into the bloodstream during periods of high activity that involve the mobilization of stored fuels to meet with increasing energy demands. The goal of this study was to determine if a sublethal exposure to PCB-126 altered the content of tissue energy supplies (carbohydrates, proteins, amino acids, triglycerides) and impaired swimming performance as well as oxygen consumption in rainbow trout (Oncorhynchus mykiss). Trout were injected intraperitoneally with a single Low (100µgkg(-1)) or High (400µgkg(-1)) dose of PCB-126 then swimming performance and metabolic rates from 1 to 9days post-injection were compared to Control (non-dosed) fish. Liver ethoxyresorufin-O-deethylase (EROD) activity was assessed as an indication of PCB-126 intoxication while plasma and white muscle tissue metabolites were analyzed as an index of physiological disturbance. Swimming performance, assessed using two successive modified critical swimming speed (Ucrit) tests, was highest for fish in the High PCB-126 treatment; however, their initial condition factor (K) was also higher, largely due to their greater body mass. Trout in the High and Low PCB-126 treatments exhibited impaired recovery following intense exercise as they swam comparatively poorly when provided a second challenge. PCB-exposed fish exhibited reduced spleen somatic indices as well as muscle glucose and glycogen contents; whereas plasma cortisol and glucose levels were elevated, indicating higher metabolic costs during recovery and muscle restoration. Overall, this research provides insights into the sublethal effects of a toxic organic compound on swimming performance in trout.

Blood pressure morning surge, exercise blood pressure response and autonomic nervous system.

OBJECTIVE: We investigated blood pressure (BP) response to exercise with respect to BP morning surge (MS), and the association between MS, exercise treadmill test (ETT) and heart rate variability (HRV) indices. DESIGN: Eighty-four healthy subjects without hypertension were enrolled. Ambulatory BP monitoring and 24-hour Holter recordings were obtained for sleep-trough MS and HRV indices: low-frequency (LF) component, high-frequency (HF) component and LF/HF ratio. ETT was performed, and BPs were obtained at rest, end of each stage, and recovery. Third-minute heart rate recovery (HRR) and BP recovery ratio (BPRR) were calculated. RESULTS: When analysed in quartiles of MS, systolic BP at low workloads was higher in the highest than in the lowest quartile, although maximum BPs at maximum exercise were not significantly different. BPRR was highest in the highest quartile in contrast to HRR, which was lowest in the highest quartile. LF/HF was highest during both at daytime and night-time in the highest quartile. BPRR and LF/HF were positively, and HRR was inversely associated with MS. CONCLUSIONS: Subjects with a high MS have higher BP at low workloads, at which most daily activities are performed, and impairment in some indices, which indirectly reflect the autonomic nervous system.

Effective removal of humic acid using xanthan gum incorporated polyethersulfone membranes.

In this study, xanthan gum (XA) was used as a hydrophilic biopolymer additive for the modification of polyethersulfone (PES) membrane to removal of humic acid (HA). The membranes are prepared using phase inversion technique and the concentration of XA was varied from 0.5 to 1.5wt%. The prepared membranes are characterized as a function of hydrophilicity, equilibrium water content (EWC), porosity studies and functional group analysis. Membrane surface and cross-sectional morphology was studied using scanning electron microscope. The lower contact angle value 64.2° was exhibited, when 1.5wt% of XA incorporated in PES membrane and this ensures that increase of hydrophilicity in pristine PES membrane. Further, higher water permeability (PWP) of 68.9(-9)m/skPa was observed for 1.5wt% of XA/PES membrane. The effect of pH on HA removal was studied for neat PES and XA/PES membranes. The rejection performance of XA incorporated in PES membranes were compared with commercial available PES membrane.

Delayed blood pressure recovery ratio and its relation to endothelial function and left ventricular diastolic function in prediabetics.

BACKGROUND: Endothelial function plays a key role in determining the clinical manifestations of established atherosclerotic lesions and has shown to be associated with suppressed sympathetic tone. Abnormal heart rate recovery (HRR) and systolic blood pressure (SBP) response during recovery has been found to have diagnostic role for detecting cardiovascular risk. AIM: To investigate whether with abnormal HRR and delayed SBP recovery ratio after exercise could predict endothelial dysfunction in prediabetic subjects. METHODS: Ninety-two prediabetic patients underwent brachial artery flow-mediated dilatation (FMD) test and a maximal exercise stress test. Seventy-eight healthy subjects served as a control group. HRR at 1 minute (HRR1 ) and SBP recovery ratio (SBPRR3 ) was defined as the SBP at minute 3 of recovery divided by SBP at peak exercise. Left ventricular diastolic function was assessed utilizing both conventional and tissue Doppler echocardiography. RESULTS: Flow-mediated dilatation was significantly decreased in prediabetics versus controls (P < 0.0001). Isovolumetric relaxation time and E/E' were significantly increased in prediabetics (P < 0.01 and <0.001). Delayed SBPRR3 was significantly correlated with impaired endothelial function and (E/E') in prediabetics (r = 0.62, P < 0.001 and r = 0.56, P < 0.001, respectively). Stepwise linear regression analysis revealed that HRR1 and SBPRR3 were significant predictors of endothelial dysfunction (r = 0.61, r(2) = 0.37, P < 0.01 and r = 0.51; r(2) = 27; P < 0.0001). CONCLUSIONS: Abnormal HRR1 and delayed SBP response detected during recovery imply a significant correlation with impaired endothelial function and diastolic dysfunction in prediabetics.