Filtering bleb area and intraocular pressure following subconjunctival injection of CTGF antibody after glaucoma filtration surgery in rabbits

AIM: To study the role of connective tissue growth factor (CTGF) antibody in inhibiting bleb scarring after glaucoma filtration surgery (GFS) in rabbit model. METHODS: GFS was performed on both eyes in five rabbits. One eye of each rabbit was chosen randomly as antibody group and received subconjunctival injection of 0.1mL CTGF antibody (50mg/L) immediately after GFS applied and on the 5 th day after GFS. The other eye of each rabbit as control group was received subconjunctival injection of 0.1mL PBS at the same time as antibody group. On postoperative days 1, 3, 5, 7, 10, and 14, the appearance of filtrating blebs was observed under slit lamp, the area and the intraocular pressure (IOP) were measured with micrometer and applanation tonometer, respectively. RESULTS: On postoperative days 1, 3, 5, 7, 10, and 14, areas of filtrating blebs in antibody group were all larger comparing with the control group (P<0.05) and IOPs of antibody group were lower than the control group(P<0.05). CONCLUSION: Subconjunctival injection of CTGF antibody can maintain larger bleb area and lower IOP after GFS in rabbit.

Relationship between Obesity, Serum Uric Acid, Serum Potassium and Glomerular Filtration Rate with Electric Left Ventricular Hypertrophy in Blacks Central Africans with High Blood Pressure

The authors conducted a retrospective study over a period of 6 months in a hypertensive population in order to determine the correlation between serum uric acid on glomerular filtration rate (GFR) and estimated serum potassium with left ventricular hypertrophy (LVH) and obesity. This study enrolled 122 patients including 63 women (51.6%). The mean age was 55.9 ± 10.6 years (range 30 to 74 years). Obesity weight was found in 38 cases (31.1%) of which 20?were men (33.9%) and 18 women (28.6%). Abdominal obesity was found in 104 cases (85.2%). The average serum uric acid in patients with obesity weight was 63.3 ± 18.9 mg/L vs 62.4 ± 14.2 mg/L for no-obese patients (p?= 0.63). The average serum potassium in obese patients was 4.06 ± 0.42 mEq/L vs 4.02 ± 0.46 mEq/L for no-obese (p?= 0.65). The average GFR was 73.4 ± 21.4 ml/L in obese patients vs 66.6 ± 22.6 ml/min in no-obese (p?= 0.03). The LVH was found in 81 cases (66.4%). The LVH was found in 65 (62.5%) obese patients vs?16 (88%) non-obese patients (OR = 4.8, 95% 1.04?-?22?p?= 0.02). Only abdominal?obesity has been correlated with left ventricular hypertrophy after multivariate analysis. Emphasis must be focused on public health actions for effective and appropriate measures against obesity and hypertension, whose prevalence is increasing in our region.

Experimental investigation of oil particles filtration on carbon nanotubes composite filter

Due to the lipophilicity of carbon nanotubes (CNTs),the carbon nanotubes composite filter for removing oil particles in cooking fumes is synthesized. The composite filter was fabricated by the chemical vapor deposition (CVD) method. The filtration characteristics of the resultant filter and the influence of the parameters were investigated. The results show that the filtration efficiency of the CNT filter during the saturation period is 99.92%, which satisfies the high efficiency particulate air (HEPA) standard. Pressure drop increases linearly before saturation and the pressure drop at the saturation stage is only two times that of the initial stage, which is far less than that of conventional glass fiber filters. The efficiency increases by enhancing filtration velocity. Pressure drops in the composite filter at the equilibrium stage are equal under different aerosol concentrations. The increase in concentration can improve the efficiency of composite filters. Therefore, the CNT filter is suitable for decreasing oil particle pollution due to its lower increase ratio of pressure drop and higher efficiency.

Decreasing serum uric acid levels are associated with improving estimated glomerular filtration rate (eGFR) in Japanese women

The aim of this study was to investigate the link between changes in a subject’s serum uric acid levels and the estimated glomerular filtration rate (eGFR) in Japanese women. We used data for 161 Japanese women (49.8 ± 11.7 years) with a 1-year follow up. eGFR was defined by a new equation developed for Japan. eGFR was negatively correlated with serum uric acid levels (r = -0.402, p

Filtration Features in the Base of the Bratsk HPP （Hydroelectric Power Station） Concrete Dam

The design protection of the base of the Bratsk HPP （Hydroelectric Power Station） dam from filtration coming from the water reservoir included the arrangement of several cement-grout curtains and the system of drainage holes in the 2nd and 4th columns. During operation, increased hydrostatic back pressure at the base of the dam was found, which indicated the low efficiency of the base design protection. To reduce back pressure B. E. Vedeneev Hydro Technic Institute proposed the device of “advanced” drainage holes from the cement-grout gallery near the upstream face. The implementation of the proposal in a number of sections of the dam has led to a decrease in back pressure, but affected filtration in the drainage system, increasing it significantly. The article examines filtration features of “advanced” drainage holes and their dependence on the severity of winters. The spread of the practice of “advanced” drainage in other sections of the dam requires caution and further investigations of the nature of filtration.

Acute Effects of Tolvaptan on Renal Hemodynamics in Autosomal Dominant Polycystic Kidney Disease —A Randomized, Cross-Over, Double Blind, Placebo-Controlled Study of Renal Plasma Flow and Glomerular Filtration Rate

Background: Previous studies have shown that reduced renal plasma flow (RPF) may play a role in progression of renal disease in autosomal dominant polycystic kidney disease (ADPKD). Tolvaptan, a vasopressin 2 antagonist, reduces growth of total kidney volume and slows the decrease in estimated glomerular filtration rate (eGFR) in ADPKD. The purpose of this randomized, cross-over, double-blind, placebo-controlled study was to investigate if acute tolvaptan treatment increases RPF in ADPKD patients. Methods: Eighteen ADPKD patients (chronic kidney disease stages I-III) were investigated twice (min. 10 days apart) after acute treatment with either tolvaptan 60 mg or placebo. Two hours after treatment RPF and GFR were estimated by Technetium-99m diethylenetriamine penta-acetic acid (99-mTc-DTPA) renography. During the examination day, central and brachial blood pressures (BP) were measured using Mobil-O-Graph? PWA. We also measured plasma concentrations of vasopressin (p-AVP), renin (PRC), angiotensin II (p-AngII) and aldosterone (p-Aldo), urine excretion of aquaporin 2 (u-AQP2), urine output (OU), urine osmolality (u-Osm) and fractional excretion of sodium (FENa). Results: 99-mTc-DTPA renography showed a similar RPF (673 ± 262 ml/min after tolvaptan vs. 650 ± 209 ml/min after placebo, p = 0.571) and GFR (78 ± 26 ml/min after tolvaptan vs. 79 ± 21 ml/min after placebo p = 0.774) after tolvaptan and placebo treatment. P-AVP and UO increased and u-Osm decreased after tolvaptan and remained unchanged during placebo. Systolic BP tended to decrease during renography during tolvaptan. Very small or insignificant changes were seen in PRC, p-AngII and p-Aldo. Conclusions: Acute tolvaptan treatment did not change renal hemodynamics in ADPKD.

Improved electrical resistance-pressure strain sensitivity of carbon nanotube network/polydimethylsiloxane composite using filtration and transfer process

The electrical resistance-pressure strain sensitivity of carbon nanotube network (NTN)/polymer composite is investigated. In this research, polydimethylsiloxane (PDMS) is used as the polymer matrix. The composite of NTN embedded in PDMS matrix has been fabricated by using filtration and transfer process. The thickness of NTN/PDMS composite can be controlled. Electrical re- sistance and pressure strain of the NTN/PDMS composite are measured simultaneously. Electrical resistance of NTN/PDMS composite has been obtained as a function of pressure strain. The NTN/PDMS composite exhibits linear change in electrical re- sistance as a result of pressure strain and has improved electrical resistance-pressure strain sensitivity. The NTN/PDMS composite has 90.6% resistance change at 6% pressure strain. The electrical resistance-pressure strain sensitivity of NTN/PDMS composite using filtration and transfer process is 2.13 times of the traditional NTN/PDMS composite. The characteristic in electrical resis- tance change implies that NTN/PDMS composite can be used as pressure strain sensors and applied to sensor systems.

Recovery of zinc from Zn-Al-Fe alloys by gas pressure filtration

The recovery of zinc from galvanizing dross and the removal of iron contained dross particles by gas pressure filtration were investigated using the model of Zn-Fe-Al alloys.The majority of molten zinc was separated after filtration,and the residue intercepted by the filter consisting mostly of dross particles.The effects of the pressure differential(p),separation temperature(T)and alloy composition on the zinc recovery and iron removal were investigated.At p=0.30 MPa and T=723 K,86.2 wt.%zinc was recovered from the Zn-4Al-2Fe alloy,and up to 99.9 wt.%of the iron was concentrated in the residue.Applying a higher pressure differential led to the improved filtration efficiency,and the desired separation temperature was about 723 K.The aluminum content in the Zn-Al-Fe alloy had little effect on separation efficiency,whereas increasing the iron content led to a decrease in the separation efficiency.Our findings demonstrate the potential of the gas pressure filtration method for the recovery of zinc from galvanizing dross.

考虑压敏效应的低渗透油藏CO_(2)辅助重力驱合理配产方法

高倾角低渗透油藏在进行水驱开发时,在油藏高部位存在大量剩余油,采收率较低,采用CO_(2)辅助重力驱,可以充分利用高倾角的地质特征,有效提高该类油藏的采出程度。但是由于CO_(2)对原油物性影响要远大于水对原油物性的影响,CO_(2)驱替过程中流体的渗流过程更加复杂,因此有必要对低渗透油藏CO_(2)重力驱合理配产优化进行研究。首先,依据油藏中任意一点压力与最小混相压力的关系,分别建立了考虑压敏效应的低渗透油藏CO_(2)重力驱混相和非混相模型;其次,运用Python对模型进行求解,同时分析了压敏系数、地层倾角、注采井距和注气速度对油藏配产的影响;最后,结合现有工作制度法和增产倍数法,对比本模型计算结果,运用tNavigtor软件对3种方法进行采收率预测。研究结果表明:运用本文方法对油藏进行合理配产具有较好的开发效果,油藏采收率相对较高,研究结果对该类低渗油藏的开发具有较好的借鉴意义。

PVDF纳米纤维膜对工业除尘滤料的性能强化

为了利用聚偏氟乙烯(PVDF)纤维膜的细直径和热/压电性提升过滤效率,用静电纺丝方法制备了PVDF纤维膜,通过SEM和XRD表征了PVDF纤维膜形貌和β晶相转化,并将PVDF纤维膜附着在PPS滤料上制备成PPS/PVDF复合滤料,对其过滤效率及压差特性进行了评估.结果表明:PVDF纤维膜无串珠结构,纤维直径分布在270~780 nm,中值427.3 nm,晶型结构以β晶相为主.随着风速升高,PPS/PVDF纤维膜复合滤料过滤效率下降更小,证明PVDF纤维膜的压电效应对微细粒子过滤效率有改善作用.随着温度的提高,PVDF纤维膜呈现热电性,复合滤料的过滤效率上升,当温度升高到70℃,其对小粒径0.3μm粒子过滤效率提升幅度最大为28.37%.

恒压过滤实验中测定值偏离理论值的原因探讨

恒压过滤实验是化工原理实验的重要组成部分,很长时间以来,河北科技大学学生在化工原理恒压过滤实验中测得的洗涤速率和最终过滤速率的比值,与理论值相差悬殊。通过对该实验过程的观察和数据处理结果的分析,指出了三个产生此问题的可能原因,并通过实验进行了验证,最终确定了主要的原因为搅拌速度、螺杆压紧程度和过滤终点,最后提出了该实验操作过程中的注意事项和实验设备改进方案。

FeSO_(4)/K_(2)S_(2)O_(8)对微细粒高黏煤泥的化学调控助滤影响

含大量高灰细泥的煤泥水在沉降浓缩阶段通常会添加大量高分子聚丙烯酰胺(PAM),加速细粒煤的沉降,但PAM的过量使用使浓缩机底流更加黏稠,导致压滤周期延长。通过向含大量高分子PAM的矿浆中添加无机盐FeSO_(4)、K_(2)S_(2)O_(8)溶液,进行不同药剂用量下煤泥的压滤试验,对药剂添加前后PAM溶液和含PAM矿浆的黏度、颗粒表面电性及颗粒团聚形态进行测试分析,探讨FeSO_(4)、K_(2)S_(2)O_(8)的作用机理。结果表明:FeSO_(4)、K_(2)S_(2)O_(8)可降解矿浆中的大分子PAM,降低矿浆黏度,形成松散的大絮体,提高速度,缩短压滤周期,降低滤饼含水率。由于FeSO_(4)兼具对PAM的化学降解和对微细颗粒的凝聚作用,其助滤效果优于K_(2)S_(2)O_(8)。当FeSO_(4)用量为1000 g/t时矿浆黏度降低482 mPa·s,压滤时间缩短70.97%,滤饼含水率降低2.31%。FeSO_(4)价廉易得,可在选煤厂高泥化煤泥脱水助滤上发挥积极作用。

磁性玄武岩滤料净化钢铁行业高温烟尘特性

针对钢铁行业高温烟尘中所含的逸散性颗粒具有易磁化的物理特性,提出新型磁性玄武岩纤维的概念及其制备方法,并分析了原位聚合法制备的磁性玄武岩纤维的拉伸性能、耐酸碱性以及耐高温性.同时,基于针刺工艺形成磁性玄武岩滤料,通过测试其孔径分布、机械强力、耐酸碱性能以及耐高温性能,验证磁性玄武岩滤料的适用性.结果表明,原位聚合法会导致原始玄武岩纤维强力下降4.6%,磁性玄武岩纤维表现出耐酸不耐碱的特性,且断裂强度保持率的上限温度为150℃.相较于原始玄武岩滤料,磁性玄武岩滤料的孔径分布更加集中,平均孔径较小.此外,原始玄武岩滤料与磁性玄武岩滤料均表现出耐酸不耐碱的特性,且断裂强度保持率的上限温度为250℃.当过滤风速为5m/min,粉尘浓度为50mg/m^(3),磁性玄武岩滤料的过滤效率相较于原始玄武岩滤料最大提高了43.67%,且滤料表面负载过程引起的压降升高基本可忽略不计.

气固逆流式移动床过滤器的实验研究

为探究操作条件对气固逆流式移动床过滤器过滤性能的影响,通过大型冷模实验,考察了气固逆流式移动床过滤器的捕集颗粒循环强度、入口粉尘浓度、表观气速及入口粉尘粒径对装备性能的影响。实验结果表明,表观气速是影响床层压降的主要因素,表现出正相关的趋势。捕集颗粒循环强度、入口粉尘浓度、粉尘粒径的改变对床层压降影响较小。捕集颗粒循环强度和入口粉尘浓度的增加使压降增加。而粉尘粒径与床层压降间的关系随时间变化,开始时粉尘粒径与压降呈正相关,但当装置运行至平稳阶段则趋于降低。装备的除尘效率与入口粉尘浓度及颗粒循环强度正相关,与粉尘粒径及表观气速负相关。但粉尘粒径越小过滤效率越高的趋势受装置内滤饼的影响,仅在粉尘中位粒径10μm以上,且入口粉尘质量浓度在0~32 g·m^(-3)出现。移动床过滤器保持稳定床层压降的同时,具有较高的除尘效率。在颗粒循环强度0.3119 kg·s^(-1),16.5~32.7 g·m^(-3)入口粉尘浓度条件下,除尘效率可达99%;且对细微(13μm以下)粉尘的粒级效率接近99.9%。

微咸水条件下微压过滤冲洗池的水头损失试验与预测模型

为探究进水流量、矿化度、滤网孔径对微灌用微压过滤冲洗池水头损失的影响,开展微压过滤冲洗池运行特性的物理模型试验,建立了微压过滤冲洗池在微咸水条件下的水头损失预测模型。结果表明,在方差分析中仅流量对微压过滤冲洗池的水头损失影响显著,确定的影响因素排序由大到小为进水流量、矿化度、滤网孔径;该模型的决定系数R^(2)为0.955,均方根误差为0.0523,平均相对误差为3.20%。建立的模型可准确预测微咸水条件下的水头损失,研究成果可为泵前过滤设备的实际应用提供技术支撑。

碳酸盐岩酸压裂缝内净压力变化规律研究

酸化压裂是开发碳酸盐岩储层最常用的增产技术,而酸压裂缝内净压力是反映裂缝扩展特征、推断裂缝几何形态的重要参数。以水力压裂裂缝延伸机理为基础,基于酸岩反应理论,考虑酸岩反应导致的缝宽变化、CO_(2)气体膨胀、酸液滤失及岩石力学性质变化,结合PKN模型,建立酸压裂缝内的净压力计算模型并进行验证。研究分析酸压裂缝内净压力的影响因素及其规律,结果表明:距缝口距离越远,水力裂缝与酸压裂缝的缝宽均越小,酸液的溶蚀作用会使裂缝宽度增大。随着液体的滤失,离缝口越远液体越少,水力裂缝与酸压裂缝净压力逐渐减小,越靠近裂缝尖端净压力衰减越快。随着作用时间延长,酸压裂缝缝宽逐渐增大,前期随着大量CO_(2)生成,净压力迅速增大,随着酸液消耗与滤失增加,之后逐渐减小并趋于稳定。随着排量的增大,滤失增大,酸压裂缝缝宽及净压力均逐渐增大且增量越来越小。在黏度较小的情况下,滤失较大,净压力逐渐减小;在黏度较大的情况下,CO_(2)膨胀作用大于滤失作用,净压力逐渐增大。随着酸液浓度的增大,酸岩反应速率增大,反应生成CO_(2)增多,净压力逐渐增大。

基于CFD的JWF1217型梳棉机滤尘管道气流分析

为了探究JWF1217型梳棉机滤尘管道内风量风压分布的合理性,建立了管道流体域模型,基于计算流体动力学(CFD)理论,采用标准k-ε湍流模型对其进行数值模拟,并根据计算结果分析管道内速度场和压力场分布。模拟结果表明:在主管道吸口800 Pa负压吸风条件下,管道内气流流动顺畅,仅在梳棉机拐角处和管道连接处出现少量涡流;管道内压力分布合理,能量消耗少,负压利用率高;各吸风点的风量风压分配符合实际生产要求。认为:JWF1217型梳棉机滤尘管道结构能合理分配气流,主管道拐角处采用大圆弧平滑过渡气流,主、支管道连接处采用主管道尾端渐宽结构,有效减小压力损失和能量消耗,有效提高了滤尘管道的吸尘能力。

煤泥脱水影响因素数学模型分析

煤泥脱水是煤炭洗选过程中的重要环节。脱水后的煤泥能够减轻运输成本,提高热值,并减少对环境的影响。利用半工业高压隔膜压滤机对煤泥脱水综合影响进行数学模型分析,通过对煤泥压滤脱水过程的研究,选取康采尼方程进行分析,以滤液量代替滤饼阻力,通过微积分、线性拟合对康采尼方程进行简化,得出特定压力下,滤液量—时间表达式:(q+160.78)2=14894.36(t-8.01)进而研究压滤脱水过程。研究结果对选煤厂现场压滤系统的操作改善提供试验基础。

高压压滤煤泥脱水效果

煤泥脱水是煤炭洗选过程中的重要环节。脱水后的煤泥能够减轻运输成本,提高热值,并减少对环境的影响。利用半工业高压隔膜压滤机研究压滤压力、压滤时间、矿浆浓度和煤泥中大于0.045 mm粒级的含量对煤泥脱水效果的影响。结果表明:压滤压力的增加能够显著降低滤饼水分,提升脱水效率,在压滤时间为180 s、矿浆浓度300 g/L时,压滤压力从1 MPa增加到5 MPa,滤饼的水分从29.89%减少到23.78%,初始脱水速率从3.5 mL/s增加到8.7 mL/s。在压滤压力3 MPa、压滤时间180 s的条件下,当大于0.045 mm的粒级含量从25%增加到100%时,滤饼的水分从29.89%降低到23.78%,压滤初始脱水速率从2.6 mL/s增加到6.3 mL/s。研究结果对选煤厂现场压滤系统的操作改善提供试验基础。