The occurrence of ultrafiltration(UF)membrane fouling frequently hampers the sustainable advancement of UF technology.Reactive self-cleaning UF membranes can effectively alleviate the problem of membrane fouling.Never...The occurrence of ultrafiltration(UF)membrane fouling frequently hampers the sustainable advancement of UF technology.Reactive self-cleaning UF membranes can effectively alleviate the problem of membrane fouling.Nevertheless,the self-cleaning process may accelerate membrane aging.Addressing these concerns,we present an innovative design concept for composite self-healing materials based on self-cleaning UF membranes.To begin,TiO_(2)nanoparticles were incorporated into the polymer molecular structure via molecular design,resulting in the synthesis of TiO_(2)/carboxyl-polyether sulfone(PES)hybrid materials.Subsequently,the nonsolvent-induced phase inversion technique was employed to prepare a novel of UF membrane.Lastly,a polyvinyl alcohol(PVA)hydrogel coating was applied to the hybrid UF membrane surface to create PVA@TiO_(2)/carboxyl-PES self-healing reactive UF membranes.By establishing a covalent bond,the TiO_(2)nanoparticles were effectively and uniformly dispersed within the UF membrane,leading to exceptional self-cleaning properties.Furthermore,the water-absorbing and swelling properties of PVA hydrogel,along with its capacity to form hydrogen bonds with water molecules,resulted in UF membranes with improved hydrophilicity and active self-healing abilities.The results demonstrated that the water contact angle of PVA@5%TiO_(2)/carboxyl-PES UF membrane was 43.1°.Following a 1-h exposure to simulated solar exposure,the water flux recovery ratio increased from 48.16%to 81.03%.Moreover,even after undergoing five cycles of 12-h simulated sunlight exposure,the UF membranes exhibited a consistent retention rate of over 97%,thus fully demonstrating their exceptional self-cleaning,antifouling,and selfhealing capabilities.We anticipate that the self-healing reactive UF membrane system will serve as a pioneering and comprehensive solution for the self-cleaning antifouling challenges encountered in UF membranes while also effectively mitigating the aging effects of reactive UF membranes.展开更多
In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycl...In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.展开更多
A non-solvent induced phase separation(NIPS)process was used to fabricate a series of sulfonated polyethersulfone(SPES)membranes blending with different concentrations of SBA-15-g-PSPA with the applications in the ult...A non-solvent induced phase separation(NIPS)process was used to fabricate a series of sulfonated polyethersulfone(SPES)membranes blending with different concentrations of SBA-15-g-PSPA with the applications in the ultrafiltration(UF)process.SBA-15 was modified with 3-methacrylate-propyltrime thoxysilane(MPS)to form SBA-15-g-MPS.It was further modified with the charge tailorable polymer chains by reacting with 3-sulfopropyl methacrylate potassium salt.The nanoparticles were uniformly dispersed and finger-like channels were developed within the membrane.The adding of surface modified SBA-15-g-PSPA nanoparticles has significantly improved membrane water permeability,hydrophilicity,and antifouling properties.The pure water fluxes of the composite SPES membranes were significantly higher than the pristine SPES membrane.For the membrane containing 5%(mass)of SBA-15-g-PSPA(MSSPA5),the pure water flux was increased dramatically to 402.15 Lm^(-2)·h^(-1),which is ~1.5 times that of MSSPA0(268.0 Lm^(-2)·h^(-1)).The high flux rate was achieved with 3%(mass)of SBA-15 nanoparticles with retained high rejection ratio 98%for natural organic matter.The results indicate that the fashioned composite membrane comprising SBA-15-g-PSPA nanoparticles have a promising future in ultrafiltration applications.展开更多
Hospitalizations for heart failure exceed 1 million per year in both the United States and Europe and more than 90%are due to symptoms and signs of fluid overload.Rates of rehospitalizations or emergency department vi...Hospitalizations for heart failure exceed 1 million per year in both the United States and Europe and more than 90%are due to symptoms and signs of fluid overload.Rates of rehospitalizations or emergency department visit at 60 days are remarkable regardless of whether loop diuretics were administered at low vs high doses or by bolus injection vs continuous infusion.Ultrafiltration(UF)has been considered a promising alternative to stepped diuretic therapy and it consists in the mechanical,adjustable removal of iso-tonic plasma water across a semipermeable membrane with the application of hydrostatic pressure gradient generated by a pump.Fluid removal with ultrafiltration presents several advantages such as elimination of higher amount of sodium with less neurohormonal activation.However,the conflicting results from UF studies highlight that patient selection and fluid removal targets are not completely understood.The best way to assess fluid status and therefore establish the fluid removal target is also still a matter of debate.Herein,we provide an up-to-date systematic review about the role of ultrafiltration among patients with fluid overload and its gaps in daily practice.展开更多
为了解决车辆行驶中面对各种复杂环境车道线检测算法精度不高的问题,提出一种基于改进的UFS网络检测算法(Ultra Fast Structure-aware Deep Lane Detection,UFS).首先,采用改进的Gamma校正对待检路面图像进行校正,降低光照、阴影等的影...为了解决车辆行驶中面对各种复杂环境车道线检测算法精度不高的问题,提出一种基于改进的UFS网络检测算法(Ultra Fast Structure-aware Deep Lane Detection,UFS).首先,采用改进的Gamma校正对待检路面图像进行校正,降低光照、阴影等的影响,以提升夜间图像纹理特征。然后引入非局部神经网络模块(Non-Local Block),充分提取图像全局特征,以提高检测可靠性。最后对改进后的算法使用Tusimple、CULane数据集进行测试。结果表明:改进后的模型在物体遮挡、光照变化、阴影干扰等复杂场景下,提升了对复杂噪声与多元场景的处理能力,车道分割的准确率有所改善,具有较好的鲁棒性。展开更多
A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration （UF） membrane and solution system, which consists of the solution, concentration polarization layer （CPL）, and ca...A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration （UF） membrane and solution system, which consists of the solution, concentration polarization layer （CPL）, and cake layer, was established by virtue of the interfacial polarization and the electrostatic field theory. The effect of some important parameters, such as the depth, conductivity of CPL, and cake layer, on the dielectric spectroscopy （or dielectric relaxation properties） of the UF system was discussed by the parameter sensitivity analysis and the dielectric measurement. The simulations indicate that the CPL can be created rapidly and the cake layer formation is the dynamic balance process of growth and erosion in the process of UF. The key factor affecting on the dielectric spectrum of UF system is the electrical properties of the CPL and the cake layer. In comparison to the results of dielectric measurement, the simulations indicate that the model proposed in this work is valid and reliable to some degree for describing and explaining the dielectric relaxation phenomenon in UF system. It is very important to further understand the fouling behavior of membrane surface and optimize the controlling techniques of membrane fouling in the process of UF.展开更多
Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV...Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV254 removals by the UF with in-line coagulation at pH 7 were increased from 28% to 53% and 40% to 78% in comparison with direct UF treatment respectively. At the same time, the analysis of high performance liquid chromatography showed that UF with coagulation had significant improvement of removal of humic acid with molecular weights less than 6000 Da in particular. Compared to direct UF, the in-line coagulation UF also kept more constant permeate flux and very slight increase oftransmembrane pressure during a filtration circle. Two typical membrane fouling models were used by inducing two coefficients Kc and Kp corresponding to cake filtration model and pore narrowing model respectively. It was found that membrane fouling by pore-narrowing effect was effectively alleviated and that by cake-filtration was much decreased by in-line coagulation. Under the condition of coagulation prior to ultrafiltration at pH 7, the cake layer formed on the membrane surface became thicker, but the membrane filtration resistance was lower than that at pH 5 with the extension of operation time.展开更多
The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）....The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.展开更多
Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only ...Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%--164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%--42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.展开更多
As fouling has always been a major drawback of membrane technology, qualitative and quantitative understanding of membrane fouling mechanisms therefore becomes vital in order to help push membrane separation technolog...As fouling has always been a major drawback of membrane technology, qualitative and quantitative understanding of membrane fouling mechanisms therefore becomes vital in order to help push membrane separation technologies forward. In this study, firstly, self-cleaning Polysulfone(PSf) membranes were synthesized by incorporation of WO_3nanoparticles(0–2 wt%) and subsequent UV irradiation for efficient ultrafiltration(UF)of landfill leachate and dairy wastewater. The membrane surface properties were characterized by scanning electron microscopy(SEM) and contact angle analysis. It was found that UV-irradiated membranes exhibited higher percent COD removals due to the hydrophilicity and photocatalytic properties of nano-WO_3. Subsequently, in order to analyze the fouling behavior of the membranes, a set of experimental data from cross-flow ultrafiltration of municipal landfill leachate and industrial dairy wastewater at 25 °C was obtained. A new model of membrane fouling was proposed based on a resistance in series concept and was fitted well with all experimental data sets.Almost all relative errors of prediction provided by the proposed model were less than 2.5%. In addition, it was revealed that this newly-developed model exhibited smooth transition between the common successive twostep pore blockage-cake filtration phenomena and thus eliminates the need to use separate equations for different mechanisms.展开更多
Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein...Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.展开更多
Dissolved organic matter （DOM） from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloid...Dissolved organic matter （DOM） from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloidal organic matter （COM; 10 kDa-0.22 pm） retentate, low molecular weight （LMW） DOM （〈10 kDa） permeate, and bulk samples were analyzed using absorption spectroscopy and three-dimensional fluorescence excitation-emission-matrix spectroscopy. The UV-visible spectra of COM were very similar to those obtained for permeate and bulk samples, decreasing monotonically with increasing wavelength. Most of the chromophoric DOM （CDOM, expressed as the absorption coefficient a355） occurred in the LMW fraction, while the percentage of CDOM in the colloidal fraction was substantially higher in the freshwater endmembet （13.4% of the total） than in the seawater endmember （6.8%）. The bulk CDOM showed a conservative mixing behavior in the estuary, while there was removal of the COM fraction and a concurrent addition of the permeate fraction in the mid-salinity sample, implying that part of the colloidal CDOM was transformed into LMW CDOM. Two humic-like components （CI： 〈250, 325/402 nm; and C2： 265, 360/458 nm） and one protein-like component （C3：275/334 nm） were identified using parallel factor analysis. The contributions of the C1, C2, and C3 components of the COM fraction to the bulk sample were 2.5%-8.7%, 4.8%-12.6%, and 7.4%-14.7%, respectively, revealing that fluorescent DOM occurred mainly in the LMW fraction in the Jiulong River Estuary. The C1 and C2 components in the retentate and permeate samples showed conservative mixing behavior, but the intensity ratio of C2/C1 was higher in the retentate than in the permeate fractions for all salinity samples, showing that the humic component was more enriched in the COM than the fulvic component. The intensity ratio of C3/（C 1 ＋C2） was much higher in the retentate than in the permeate fraction for mid-salinity and seawater samples, revealing that the protein-like component was relatively more enriched in COM than the humic-like component. The contribution of the protein-like component （C3） to the total fluorescence in the retentate increased from 14% in the freshwater endmember to 72% for the seawater endmember samples, clearly indicating the variation of dominance by the humic-like component compared to the protein-like component during the estuarine mixing process of COM.展开更多
Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based ce...Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry（LC/MS） method,also known as screening method for mitochondria-targeted bioactive constituents（SM-MBC）. This method allowed searching natural mitochondria-targeting compounds from traditional Chinese medicines（TCMs）, including Puerariae Radix（PR） and Chuanxiong Radix（CR）. A total of 23 active compounds were successfully discovered from the two TCMs extracts. Among these 23 hit compounds, 17 were identified by LC/MS, 12 of which were novel mitochondria-targeting compounds. Among these, 6 active compounds were analyzed in vitro for pharmacological tests and found able to affect mitochondrial functions. We also investigated the effects of the hit compounds on Hep G2 cell proliferation and on loss of cardiomyocyte viability induced by hypoxia/reoxygenation injury. The results obtained are useful for in-depth understanding of mechanisms underlying TCMs therapeutic effects at mitochondria level and for developing novel potential drugs using TCMs as lead compounds. Finally, we showed that SM-MBC was an efficient protocol for the rapid screening of mitochondria-targeting constituents from complex samples such as PR and CR extracts.展开更多
The current models of cardiorenal syndrome(CRS) are mainly based on a cardiocentric approach; they assume that worsening renal function is an adverse consequence of the decline in cardiac function rather than a separa...The current models of cardiorenal syndrome(CRS) are mainly based on a cardiocentric approach; they assume that worsening renal function is an adverse consequence of the decline in cardiac function rather than a separate and independent pathologic phenomenon. If this assumption were true,then mechanical extraction of fluid(i.e.,ultrafiltration therapy) would be expected to portend positive impact on renal hemodynamics and function through improvement in cardio-circulatory physiology and reduction in neurohormonal activation. However,currently available ultrafiltration trials,whether in acute heart failure(AHF) or in CRS,have so far failed to show any improvement in renal function; they have reported no impact or even observed adverse renal outcomes in this setting. Moreover,the presence or absence of renal dysfunction seems to affect the overall safety and efficacy of ultrafiltration therapy in AHF. This manuscript briefly reviews cardiorenal physiology in AHF and concludes that therapeutic options for CRS should not only target cardio-circulatory status of the patients,but they need to also have the ability of addressing the adverse homeostatic consequences of the associated decline in renal function. Peritoneal dialysis(PD) can be such an option for the chronic cases of CRS as it has been shown to provide efficient intracorporeal ultrafiltration and sodium extraction in volume overloaded patients while concurrently correcting the metabolic consequences of diminished renal function. Currently available trials on PD in heart failure have shown the safety and efficacy of this therapeutic modality for patients with chronic CRS and suggest that it could represent a pathophysiologically and conceptually relevant option in this setting.展开更多
基金supported by the National Natural Science Foundation of China(51978133,52100026,U20A20322,52170151,51978132)the Fundamental Research Funds for the Central Universities of China(2412021QD022)+1 种基金the Key Research and Development Project of Hainan Province(ZDYF2022SHFZ298)the Industrialization Cultivation Project of Jilin Provincial Department of Education(JJKH20221174CY)。
文摘The occurrence of ultrafiltration(UF)membrane fouling frequently hampers the sustainable advancement of UF technology.Reactive self-cleaning UF membranes can effectively alleviate the problem of membrane fouling.Nevertheless,the self-cleaning process may accelerate membrane aging.Addressing these concerns,we present an innovative design concept for composite self-healing materials based on self-cleaning UF membranes.To begin,TiO_(2)nanoparticles were incorporated into the polymer molecular structure via molecular design,resulting in the synthesis of TiO_(2)/carboxyl-polyether sulfone(PES)hybrid materials.Subsequently,the nonsolvent-induced phase inversion technique was employed to prepare a novel of UF membrane.Lastly,a polyvinyl alcohol(PVA)hydrogel coating was applied to the hybrid UF membrane surface to create PVA@TiO_(2)/carboxyl-PES self-healing reactive UF membranes.By establishing a covalent bond,the TiO_(2)nanoparticles were effectively and uniformly dispersed within the UF membrane,leading to exceptional self-cleaning properties.Furthermore,the water-absorbing and swelling properties of PVA hydrogel,along with its capacity to form hydrogen bonds with water molecules,resulted in UF membranes with improved hydrophilicity and active self-healing abilities.The results demonstrated that the water contact angle of PVA@5%TiO_(2)/carboxyl-PES UF membrane was 43.1°.Following a 1-h exposure to simulated solar exposure,the water flux recovery ratio increased from 48.16%to 81.03%.Moreover,even after undergoing five cycles of 12-h simulated sunlight exposure,the UF membranes exhibited a consistent retention rate of over 97%,thus fully demonstrating their exceptional self-cleaning,antifouling,and selfhealing capabilities.We anticipate that the self-healing reactive UF membrane system will serve as a pioneering and comprehensive solution for the self-cleaning antifouling challenges encountered in UF membranes while also effectively mitigating the aging effects of reactive UF membranes.
基金supported by the National Key Research and Development Program of China(2022YFC3801101)National Natural Science Foundation of China(52170028)+1 种基金the State Key Laboratory of Urban Water Resource and Environment,Harbin Institute of Technology(2023DX11)National Engineering Research Center for Safe Sludge Disposal and Resource Recovery(2021A003).
文摘In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.
文摘A non-solvent induced phase separation(NIPS)process was used to fabricate a series of sulfonated polyethersulfone(SPES)membranes blending with different concentrations of SBA-15-g-PSPA with the applications in the ultrafiltration(UF)process.SBA-15 was modified with 3-methacrylate-propyltrime thoxysilane(MPS)to form SBA-15-g-MPS.It was further modified with the charge tailorable polymer chains by reacting with 3-sulfopropyl methacrylate potassium salt.The nanoparticles were uniformly dispersed and finger-like channels were developed within the membrane.The adding of surface modified SBA-15-g-PSPA nanoparticles has significantly improved membrane water permeability,hydrophilicity,and antifouling properties.The pure water fluxes of the composite SPES membranes were significantly higher than the pristine SPES membrane.For the membrane containing 5%(mass)of SBA-15-g-PSPA(MSSPA5),the pure water flux was increased dramatically to 402.15 Lm^(-2)·h^(-1),which is ~1.5 times that of MSSPA0(268.0 Lm^(-2)·h^(-1)).The high flux rate was achieved with 3%(mass)of SBA-15 nanoparticles with retained high rejection ratio 98%for natural organic matter.The results indicate that the fashioned composite membrane comprising SBA-15-g-PSPA nanoparticles have a promising future in ultrafiltration applications.
文摘Hospitalizations for heart failure exceed 1 million per year in both the United States and Europe and more than 90%are due to symptoms and signs of fluid overload.Rates of rehospitalizations or emergency department visit at 60 days are remarkable regardless of whether loop diuretics were administered at low vs high doses or by bolus injection vs continuous infusion.Ultrafiltration(UF)has been considered a promising alternative to stepped diuretic therapy and it consists in the mechanical,adjustable removal of iso-tonic plasma water across a semipermeable membrane with the application of hydrostatic pressure gradient generated by a pump.Fluid removal with ultrafiltration presents several advantages such as elimination of higher amount of sodium with less neurohormonal activation.However,the conflicting results from UF studies highlight that patient selection and fluid removal targets are not completely understood.The best way to assess fluid status and therefore establish the fluid removal target is also still a matter of debate.Herein,we provide an up-to-date systematic review about the role of ultrafiltration among patients with fluid overload and its gaps in daily practice.
文摘为了解决车辆行驶中面对各种复杂环境车道线检测算法精度不高的问题,提出一种基于改进的UFS网络检测算法(Ultra Fast Structure-aware Deep Lane Detection,UFS).首先,采用改进的Gamma校正对待检路面图像进行校正,降低光照、阴影等的影响,以提升夜间图像纹理特征。然后引入非局部神经网络模块(Non-Local Block),充分提取图像全局特征,以提高检测可靠性。最后对改进后的算法使用Tusimple、CULane数据集进行测试。结果表明:改进后的模型在物体遮挡、光照变化、阴影干扰等复杂场景下,提升了对复杂噪声与多元场景的处理能力,车道分割的准确率有所改善,具有较好的鲁棒性。
基金This work was supported by the Natural Science Foundation of Shandong Province of China （No.Q2007B01）.
文摘A dielectric analysis model for the fouling layer on the polyethersulfone composite ultrafiltration （UF） membrane and solution system, which consists of the solution, concentration polarization layer （CPL）, and cake layer, was established by virtue of the interfacial polarization and the electrostatic field theory. The effect of some important parameters, such as the depth, conductivity of CPL, and cake layer, on the dielectric spectroscopy （or dielectric relaxation properties） of the UF system was discussed by the parameter sensitivity analysis and the dielectric measurement. The simulations indicate that the CPL can be created rapidly and the cake layer formation is the dynamic balance process of growth and erosion in the process of UF. The key factor affecting on the dielectric spectrum of UF system is the electrical properties of the CPL and the cake layer. In comparison to the results of dielectric measurement, the simulations indicate that the model proposed in this work is valid and reliable to some degree for describing and explaining the dielectric relaxation phenomenon in UF system. It is very important to further understand the fouling behavior of membrane surface and optimize the controlling techniques of membrane fouling in the process of UF.
基金The National Natural Science Foundation of China (No. 50138020)
文摘Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV254 removals by the UF with in-line coagulation at pH 7 were increased from 28% to 53% and 40% to 78% in comparison with direct UF treatment respectively. At the same time, the analysis of high performance liquid chromatography showed that UF with coagulation had significant improvement of removal of humic acid with molecular weights less than 6000 Da in particular. Compared to direct UF, the in-line coagulation UF also kept more constant permeate flux and very slight increase oftransmembrane pressure during a filtration circle. Two typical membrane fouling models were used by inducing two coefficients Kc and Kp corresponding to cake filtration model and pore narrowing model respectively. It was found that membrane fouling by pore-narrowing effect was effectively alleviated and that by cake-filtration was much decreased by in-line coagulation. Under the condition of coagulation prior to ultrafiltration at pH 7, the cake layer formed on the membrane surface became thicker, but the membrane filtration resistance was lower than that at pH 5 with the extension of operation time.
基金Project supported by the Hi-Tech Research and Development Project(863) of China (No. 2002AA601130)the National Science and Technology Research Project (No, 2003BA808A17)
文摘The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.
基金The National Basic Research Program (973) of China (No. 2004CB418505)
文摘Concentration polarization and membrane fouling remain one of the major hurdles for the implementation of ultrafiltration of produced water. Although many applications for ultrafiltration were already suggested, only few were implemented on an industrial scale. Among those techniques, turbulence promoter can be more simple and effective in overcoming membrane fouling and enhancing membrane flux. As for the result that turbulence promoter increase fluid velocity, wall shear rates and produce secondary flows or instabilities, the influence of turbulence promoter was investigated on permeate flux during produced water ultrafiltration and the potential application of this arrangement for an industrial development. Experimental investigations were performed on 100 KDa molecular weight cut-off PVDF single-channel tubular membrane module using four kinds of turbulence promoters. It is observed that the significant flux enhancement in the range of 83%--164% was achieved while the hydraulic dissipated power per unit volume of permeate decreased from 31%--42%, which indicated that the using of turbulence promoter is more efficient than operation without the turbulence promoter. The effects of transmembrane pressure and cross-flow velocity with and without turbulence promoter were studied as well. Among the four kinds of turbulence promoters, winding inserts with 20.0 mm pitch and 1.0 mm wire diameter showed better performances than the others did.
基金Supported by Iran Nanotechnology Initiative Council grant to the Nanotechnology Research Institute(NIR)at Babol University of Technology,Iran
文摘As fouling has always been a major drawback of membrane technology, qualitative and quantitative understanding of membrane fouling mechanisms therefore becomes vital in order to help push membrane separation technologies forward. In this study, firstly, self-cleaning Polysulfone(PSf) membranes were synthesized by incorporation of WO_3nanoparticles(0–2 wt%) and subsequent UV irradiation for efficient ultrafiltration(UF)of landfill leachate and dairy wastewater. The membrane surface properties were characterized by scanning electron microscopy(SEM) and contact angle analysis. It was found that UV-irradiated membranes exhibited higher percent COD removals due to the hydrophilicity and photocatalytic properties of nano-WO_3. Subsequently, in order to analyze the fouling behavior of the membranes, a set of experimental data from cross-flow ultrafiltration of municipal landfill leachate and industrial dairy wastewater at 25 °C was obtained. A new model of membrane fouling was proposed based on a resistance in series concept and was fitted well with all experimental data sets.Almost all relative errors of prediction provided by the proposed model were less than 2.5%. In addition, it was revealed that this newly-developed model exhibited smooth transition between the common successive twostep pore blockage-cake filtration phenomena and thus eliminates the need to use separate equations for different mechanisms.
基金Supported by the National Natural Science Foundation of China(21776126)the National Basic Research Program of China(2015CB655301)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20150063)partially supported by the Open Fund of State Key Laboratory of Separation Membranes and Membrane Processes(M1-201702).
文摘Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.
基金The National Natural Science Foundation of China under contract No.41276064the Chinese Scholarship Council Program and the Program for New Century Excellent Talents(NCET)to Weidong Guothe Fundamental Research Funds for the Central Universities under contract No.201112G011
文摘Dissolved organic matter （DOM） from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloidal organic matter （COM; 10 kDa-0.22 pm） retentate, low molecular weight （LMW） DOM （〈10 kDa） permeate, and bulk samples were analyzed using absorption spectroscopy and three-dimensional fluorescence excitation-emission-matrix spectroscopy. The UV-visible spectra of COM were very similar to those obtained for permeate and bulk samples, decreasing monotonically with increasing wavelength. Most of the chromophoric DOM （CDOM, expressed as the absorption coefficient a355） occurred in the LMW fraction, while the percentage of CDOM in the colloidal fraction was substantially higher in the freshwater endmembet （13.4% of the total） than in the seawater endmember （6.8%）. The bulk CDOM showed a conservative mixing behavior in the estuary, while there was removal of the COM fraction and a concurrent addition of the permeate fraction in the mid-salinity sample, implying that part of the colloidal CDOM was transformed into LMW CDOM. Two humic-like components （CI： 〈250, 325/402 nm; and C2： 265, 360/458 nm） and one protein-like component （C3：275/334 nm） were identified using parallel factor analysis. The contributions of the C1, C2, and C3 components of the COM fraction to the bulk sample were 2.5%-8.7%, 4.8%-12.6%, and 7.4%-14.7%, respectively, revealing that fluorescent DOM occurred mainly in the LMW fraction in the Jiulong River Estuary. The C1 and C2 components in the retentate and permeate samples showed conservative mixing behavior, but the intensity ratio of C2/C1 was higher in the retentate than in the permeate fractions for all salinity samples, showing that the humic component was more enriched in the COM than the fulvic component. The intensity ratio of C3/（C 1 ＋C2） was much higher in the retentate than in the permeate fraction for mid-salinity and seawater samples, revealing that the protein-like component was relatively more enriched in COM than the humic-like component. The contribution of the protein-like component （C3） to the total fluorescence in the retentate increased from 14% in the freshwater endmember to 72% for the seawater endmember samples, clearly indicating the variation of dominance by the humic-like component compared to the protein-like component during the estuarine mixing process of COM.
基金Financial support from the National Natural Science Foundation of China (Grant 81660596, 81673395 and 81373921)the Research Fund for the Doctoral Program of Higher Education of China (Grant 20130001110057)the Application and Basis Research Project of Yunnan China (Grant 2017FF117-(013) and 2016FD050)
文摘Mitochondria regulate numerous crucial cell processes, including energy production, apoptotic cell death, oxidative stress, calcium homeostasis and lipid metabolism. Here, we applied an efficient mitochondria-based centrifugal ultrafiltration/liquid chromatography/mass spectrometry（LC/MS） method,also known as screening method for mitochondria-targeted bioactive constituents（SM-MBC）. This method allowed searching natural mitochondria-targeting compounds from traditional Chinese medicines（TCMs）, including Puerariae Radix（PR） and Chuanxiong Radix（CR）. A total of 23 active compounds were successfully discovered from the two TCMs extracts. Among these 23 hit compounds, 17 were identified by LC/MS, 12 of which were novel mitochondria-targeting compounds. Among these, 6 active compounds were analyzed in vitro for pharmacological tests and found able to affect mitochondrial functions. We also investigated the effects of the hit compounds on Hep G2 cell proliferation and on loss of cardiomyocyte viability induced by hypoxia/reoxygenation injury. The results obtained are useful for in-depth understanding of mechanisms underlying TCMs therapeutic effects at mitochondria level and for developing novel potential drugs using TCMs as lead compounds. Finally, we showed that SM-MBC was an efficient protocol for the rapid screening of mitochondria-targeting constituents from complex samples such as PR and CR extracts.
文摘The current models of cardiorenal syndrome(CRS) are mainly based on a cardiocentric approach; they assume that worsening renal function is an adverse consequence of the decline in cardiac function rather than a separate and independent pathologic phenomenon. If this assumption were true,then mechanical extraction of fluid(i.e.,ultrafiltration therapy) would be expected to portend positive impact on renal hemodynamics and function through improvement in cardio-circulatory physiology and reduction in neurohormonal activation. However,currently available ultrafiltration trials,whether in acute heart failure(AHF) or in CRS,have so far failed to show any improvement in renal function; they have reported no impact or even observed adverse renal outcomes in this setting. Moreover,the presence or absence of renal dysfunction seems to affect the overall safety and efficacy of ultrafiltration therapy in AHF. This manuscript briefly reviews cardiorenal physiology in AHF and concludes that therapeutic options for CRS should not only target cardio-circulatory status of the patients,but they need to also have the ability of addressing the adverse homeostatic consequences of the associated decline in renal function. Peritoneal dialysis(PD) can be such an option for the chronic cases of CRS as it has been shown to provide efficient intracorporeal ultrafiltration and sodium extraction in volume overloaded patients while concurrently correcting the metabolic consequences of diminished renal function. Currently available trials on PD in heart failure have shown the safety and efficacy of this therapeutic modality for patients with chronic CRS and suggest that it could represent a pathophysiologically and conceptually relevant option in this setting.
