Different methods of hilar clamping during partial nephrectomy: Impact on renal function.

PubMed

Lee, Jeong Woo; Kim, Hwanik; Choo, Minsoo; Park, Yong Hyun; Ku, Ja Hyeon; Kim, Hyeon Hoe; Kwak, Cheol

2014-03-01

To evaluate the impact of different hilar clamping methods on changes in renal function after partial nephrectomy. We analyzed the clinical data of 369 patients who underwent partial nephrectomy for a single renal tumor of size ≤4.0 cm and a normal contralateral kidney. Patients were separated into three groups depending on hilar clamping method: non-clamping, cold ischemia and warm ischemia. Estimated glomerular filtration rate was examined at preoperative, nadir and 1 year postoperatively. Percent change in estimated glomerular filtration rate was used as the parameter to assess the renal functional outcome. Percent change in nadir estimated glomerular filtration rate in the non-clamping group was significantly less compared with the cold ischemia and warm ischemia groups (P < 0.001). However, no significant differences among the groups were noted in percent change of estimated glomerular filtration rate at 1 year (P = 0.348). The cold ischemia group had a similar serial change of postoperative renal function compared with the warm ischemia group. Percent change in 1-year estimated glomerular filtration rate increased with increasing ischemia time in the cold ischemia (P for trend = 0.073) and warm ischemia groups (P for trend = 0.010). On multivariate analysis, hilar clamping (both warm ischemia and cold ischemia) were significantly associated with percent change in nadir estimated glomerular filtration rate, but not in 1-year estimated glomerular filtration rate. Non-clamping partial nephrectomy results in a lower percent change in nadir estimated glomerular filtration rate, whereas it carries an estimated glomerular filtration rate change at 1 year that is similar to partial nephrectomy with cold ischemia and warm ischemia. Cold ischemia and warm ischemia provide a similar effect on renal function. Therefore, when hilar clamping is required, minimization of ischemia time is necessary. © 2013 The Japanese Urological Association.

Compensatory Structural and Functional Adaptation after Radical Nephrectomy for Renal Cell Carcinoma According to Preoperative Stage of Chronic Kidney Disease.

PubMed

Choi, Don Kyoung; Jung, Se Bin; Park, Bong Hee; Jeong, Byong Chang; Seo, Seong Il; Jeon, Seong Soo; Lee, Hyun Moo; Choi, Han-Yong; Jeon, Hwang Gyun

2015-10-01

We investigated structural hypertrophy and functional hyperfiltration as compensatory adaptations after radical nephrectomy in patients with renal cell carcinoma according to the preoperative chronic kidney disease stage. We retrospectively identified 543 patients who underwent radical nephrectomy for renal cell carcinoma between 1997 and 2012. Patients were classified according to preoperative glomerular filtration rate as no chronic kidney disease--glomerular filtration rate 90 ml/minute/1.73 m(2) or greater (230, 42.4%), chronic kidney disease stage II--glomerular filtration rate 60 to less than 90 ml/minute/1.73 m(2) (227, 41.8%) and chronic kidney disease stage III--glomerular filtration rate 30 to less than 60 ml/minute/1.73 m(2) (86, 15.8%). Computerized tomography performed within 2 months before surgery and 1 year after surgery was used to assess functional renal volume for measuring the degree of hypertrophy of the remnant kidney, and the preoperative and postoperative glomerular filtration rate per unit volume of functional renal volume was used to calculate the degree of hyperfiltration. Among all patients (mean age 56.0 years) mean preoperative glomerular filtration rate, functional renal volume and glomerular filtration rate/functional renal volume were 83.2 ml/minute/1.73 m(2), 340.6 cm(3) and 0.25 ml/minute/1.73 m(2)/cm(3), respectively. The percent reduction in glomerular filtration rate was statistically significant according to chronic kidney disease stage (no chronic kidney disease 31.2% vs stage II 26.5% vs stage III 12.8%, p <0.001). However, the degree of hypertrophic functional renal volume in the remnant kidney was not statistically significant (no chronic kidney disease 18.5% vs stage II 17.3% vs stage III 16.5%, p=0.250). The change in glomerular filtration rate/functional renal volume was statistically significant (no chronic kidney disease 18.5% vs stage II 20.1% vs stage III 45.9%, p <0.001). Factors that increased glomerular filtration rate/functional renal volume above the mean value were body mass index (p=0.012), diabetes mellitus (p=0.023), hypertension (p=0.015) and chronic kidney disease stage (p <0.001). Patients with a lower preoperative glomerular filtration rate had a smaller reduction in postoperative renal function than those with a higher preoperative glomerular filtration rate due to greater degrees of functional hyperfiltration. Copyright © 2015 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Gallium-68 EDTA PET/CT for Renal Imaging.

PubMed

Hofman, Michael S; Hicks, Rodney J

2016-09-01

Nuclear medicine renal imaging provides important functional data to assist in the diagnosis and management of patients with a variety of renal disorders. Physiologically stable metal chelates like ethylenediaminetetraacetic acid (EDTA) and diethylenetriamine penta-acetate (DTPA) are excreted by glomerular filtration and have been radiolabelled with a variety of isotopes for imaging glomerular filtration and quantitative assessment of glomerular filtration rate. Gallium-68 ((68)Ga) EDTA PET usage predates Technetium-99m ((99m)Tc) renal imaging, but virtually disappeared with the widespread adoption of gamma camera technology that was not optimal for imaging positron decay. There is now a reemergence of interest in (68)Ga owing to the greater availability of PET technology and use of (68)Ga to label other radiotracers. (68)Ga EDTA can be used a substitute for (99m)Tc DTPA for wide variety of clinical indications. A key advantage of PET for renal imaging over conventional scintigraphy is 3-dimensional dynamic imaging, which is particularly helpful in patients with complex anatomy in whom planar imaging may be nondiagnostic or difficult to interpret owing to overlying structures containing radioactive urine that cannot be differentiated. Other advantages include accurate and absolute (rather than relative) camera-based quantification, superior spatial and temporal resolution and integrated multislice CT providing anatomical correlation. Furthermore, the (68)Ga generator enables on-demand production at low cost, with no additional patient radiation exposure compared with conventional scintigraphy. Over the past decade, we have employed (68)Ga EDTA PET/CT primarily to answer difficult clinical questions in patients in whom other modalities have failed, particularly when it was envisaged that dynamic 3D imaging would be of assistance. We have also used it as a substitute for (99m)Tc DTPA if unavailable owing to supply issues, and have additionally examined the role of (68)Ga EDTA PET/CT for measuring glomerular filtration rate and split renal function. Copyright © 2016 Elsevier Inc. All rights reserved.

Gravity filtration performances of the bio-diatomite dynamic membrane reactor for slightly polluted surface water purification.

PubMed

Chu, Huaqiang; Dong, Bingzhi; Zhang, Yalei; Zhou, Xuefei

2012-01-01

A bio-diatomite dynamic membrane (BDDM) reactor for surface water treatment under a water head of 30, 40, 50, 60 and 70 cm, respectively, was investigated, which was very effective for pollutants removal. The water head exerted strong influences on filtration flux of BDDM during the precoating process, as well as on the formation of BDDM and turbidity variations. A high filtration flux (approximately 200-300 L/m2 h) could be achieved in the long filtration times of BDDM with a stable effluent turbidity of approximately 0.11-0.25 NTU. The BDDM could remove particles larger than 25 μm completely. The adopted sintered diatomite mainly consisted of macro pores, which were beneficial for improving the filtration flux of BDDM. During the backwash stage, the BDDM could be removed completely by the air backwash.

Influence of thyroid function on glomerular filtration rate and other estimates of kidney function in two pediatric patients.

PubMed

Uemura, Osamu; Iwata, Naoyuki; Nagai, Takuhito; Yamakawa, Satoshi; Hibino, Satoshi; Yamamoto, Masaki; Nakano, Masaru; Tanaka, Kazuki

2018-05-01

To determine the optimal method of evaluating kidney function in patients with thyroid dysfunction, this study compared the estimated glomerular filtration rate derived from serum creatinine, cystatin C, or β2-microglobulin with inulin or creatinine clearance in two pediatric patients, one with hypothyroidism and the other with hyperthyroidism. It was observed that the kidney function decreased in a hypothyroid child and enhanced in a hyperthyroid child, with their kidney function becoming normalized by treatment with drugs, which normalized their thyroid function. Kidney function cannot be accurately evaluated using cystatin C-based or β2-microglobulin-based estimated glomerular filtration rate in patients with thyroid dysfunction, as these tests overestimated glomerular filtration rate in a patient with hypothyroidism and underestimated glomerular filtration rate in a patient with hyperthyroidism, perhaps through a metabolic rate-mediated mechanism. In both our patients, 24-h urinary creatinine secretion was identical before and after treatment, suggesting that creatinine production is not altered in patients with thyroid dysfunction. Therefore, kidney function in patients with thyroid dysfunction should be evaluated using creatinine-based estimated glomerular filtration rate.

Experimental study of the effect of polyanionic cellulose on process of filtrate loss of low-solids drilling fluid

NASA Astrophysics Data System (ADS)

yang, P.

2013-12-01

Experimental study of the effect of polyanionic cellulose on process of filtrate loss of low-solids drilling fluid Ping Yang 1,2, Min-hui Wu2, Xue-wen Zhu2, Tao Deng2, Xue-qing Sun2 1. Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai 200092,China 2. Department of Geotechnical Engineering,Tongji University,Shanghai 200092,China Abstract The process of filtrate loss of low-solids drilling fluid was tested by changing the polyanionic cellulose content in low-solids drilling fluid. The effect of polyanionic cellulose on process of filtrate loss of low-solids drilling fluid was analyzed. The test results showed that when time of filtration is same, the volume of filtrate loss decreases linearly with increasing polyanionic cellulose content. When polyanionic cellulose content is same, the rate of filtrate loss decreases nonlinearly with increasing time and the rate of filtrate loss will reach a stable value.The volume of filtrate loss in 7 to 8 minutes can reaches half of the total volume of filtrate loss. At the same time, the rate of filtrate loss of drilling fluid decreases nonlinearly with increasing viscosity.When the apparent viscosity is between 3.5~4.15 MPa.s, decrease speed of rate of filtrate loss of drilling fluid is quick. The results are helpful for characteristics evaluation of filtrate loss of drilling fluid and control of filtrate loss. Keyword Polyanionic Cellulose,Drilling Fluid,Process of Filtrate Loss Acknowledgments This investigation was supported by the National Natural Science Foundation of China (projects No. 41002093 and 41072205); the Fundamental Research Funds for the Central Universities; the Shanghai Leading Academic Discipline Project (project No. B308), Tongji University; and the Program for Young Excellent Talents, Tongji University. The authors are extremely grateful for the financial support from these five organizations.

Crumb rubber filtration: a potential technology for ballast water treatment.

PubMed

Tang, Zhijian; Butkus, Michael A; Xie, Yuefeng F

2006-05-01

The removal of turbidity, particles, phytoplankton and zooplankton in water by crumb rubber filtration was investigated. A substantial reduction was achieved. Of the three variables, filter depth, media size and filtration rate, media size had the most significant influence. Smaller media size favored higher removal efficiency of all targeted matter. There was no apparent relationship between removal efficiency and filter depth. Higher filtration rate resulted in lower removal efficiency and higher head loss. Compared with conventional granular media filters, crumb rubber filters required less backwash, and developed lower head loss. Consequently crumb rubber filters could be run for a longer time or allow a higher filtration rate. The results also indicate that the crumb rubber filtration alone did not achieve the target removal of invasive species. However, crumb rubber filtration could potentially be used as a primary treatment technology to enhance the efficiency of a secondary treatment process (e.g., disinfection).

Further evaluation of alternative air-filtration systems for reducing the transmission of Porcine reproductive and respiratory syndrome virus by aerosol

PubMed Central

Deen, John; Cano, Jean Paul; Batista, Laura; Pijoan, Carlos

2006-01-01

Abstract The purpose of this study was to compare 4 methods for the reduction of aerosol transmission of Porcine reproductive and respiratory syndrome virus (PRRSV): high-efficiency particulate air (HEPA) filtration, 2×-low-cost filtration, bag filtration, and use of a filter tested against particles derived from dioctylphthalate (DOP). The HEPA-filtration system used a prefilter screen, a bag filter (Eurovent [EU] 8 rating), and a HEPA filter (EU13 rating). The low-cost-filtration system contained mosquito netting (prefilter), 2 fiberglass furnace filters, and 2 electrostatic furnace filters. Bag filtration involved the use of a filter rated EU8 and a minimum efficiency reporting value (MERV) of 14. The 95%-DOP, 0.3-μm-filtration system involved a pleat-in-pleat V-bank disposable filter with a 95% efficiency rating for particles 0.3 μm or greater in diameter and ratings of EU9 and MERV 15. No form of intervention was used in the control group. The experimental facilities consisted of 2 chambers connected by a 1.3-m-long duct containing the treatments. Recipient pigs, housed in chamber 2, were exposed to artificial aerosols created by a mechanically operated mister containing modified live PRRSV vaccine located in chamber 1. Aerosol transmission of PRRSV occurred in 0 of the 10 HEPA-filtration replicates, 2 of the 10 bag-filtration replicates, 4 of the 10 low-cost-filtration replicates, 0 of the 10 95%-DOP, 0.3-μm-filtration replicates, and all 10 of the control replicates. Using a similar approach, we further evaluated the HEPA- and 95%-DOP, 0.3-μm-filtration systems. Infection was not observed in any of the 76 HEPA-filtration replicates but was observed in 2 of the 76 95%-DOP, 0.3-μm replicates and 42 of the 50 control replicates. Although the difference between the 95%-DOP, 0.3-μm and control replicates was significant (P < 0.0005), so was the level of failure of the 95%-DOP, 0.3-μm system (P = 0.02). In conclusion, under the conditions of this study, some methods of air filtration were significantly better than others in reducing aerosol transmission of PRRSV, and HEPA filtration was the only system that completely prevented transmission. PMID:16850938

Sperm preparation through Sephadex™ filtration improves in vitro fertilization rate of buffalo oocytes.

PubMed

Husna, A U; Azam, A; Qadeer, S; Awan, M A; Nasreen, S; Shahzad, Q; Fouladi-Nashta, A; Khalid, M; Akhter, S

2018-04-01

Routinely, swim-up method is used to separate high-quality sperm; however, long processing time and close cell-to-cell contact during the centrifugation step are inevitable elements of oxidative stress to sperm. The objective was to evaluate Sephadex ™ and glass wool filtration to separate motile, intact and viable sperm for in vitro fertilization in buffalo. The cumulus-oocyte complexes (COCs) were collected from ovaries of slaughtered buffaloes by aspiration and matured for 24 hr in CO 2 incubator at 38.5°C and 5% CO 2 . Matured COCs were rinsed twice in fertilization TALP and placed in the pre-warmed fertilization medium without sperm. Cryopreserved buffalo semen was thawed at 37°C for 30 s and processed through Sephadex ™ , glass wool filtration and swim-up (control). Total and motile sperm recovery rates were assessed, resuspended in fertilization TALP and incubated for 15-20 min in CO 2 incubator. Samples prepared by each method were divided into two aliquots: one aliquot was studied for sperm quality (progressive motility, membrane integrity, viability, liveability), while the other was subjected to co-incubation with sets of 10-15 in vitro matured oocytes. Data on sperm quality were analysed by ANOVA, while in vitro fertilizing rates were compared by chi-squared test using SPSS-20. Least significant difference (LSD) test was used to compare treatment means. Glass wool filtration yielded higher total and motile sperm recovery rate, while Sephadex ™ filtration improved (p < .05) sperm quality (progressive motility, membrane integrity, viability, liveability). Sperm preparation through Sephadex filtration yielded higher in vitro fertilization rate in terms of cleavage rate compared to glass wool filtration and swim-up (control). In conclusion, cryopreserved Nili-Ravi buffalo sperm selected through Sephadex filtration showed improved quality and yielded better fertilization rates (cleavage rate) of in vitro matured/fertilized oocytes. Sephadex filtration could be a promising technique for use in in vitro fertilization in buffalo. © 2017 Blackwell Verlag GmbH.

Applicability of dynamic membrane technology in anaerobic membrane bioreactors.

PubMed

Ersahin, Mustafa Evren; Ozgun, Hale; Tao, Yu; van Lier, Jules B

2014-01-01

This study investigated the applicability of dynamic membrane technology in anaerobic membrane bioreactors for the treatment of high strength wastewaters. A monofilament woven fabric was used as support material for dynamic membrane formation. An anaerobic dynamic membrane bioreactor (AnDMBR) was operated under a variety of operational conditions, including different sludge retention times (SRTs) of 20 and 40 days in order to determine the effect of SRT on both biological performance and dynamic membrane filtration characteristics. High COD removal efficiencies exceeding 99% were achieved during the operation at both SRTs. Higher filtration resistances were measured during the operation at SRT of 40 days in comparison to SRT of 20 days, applying a stable flux of 2.6 L/m(2) h. The higher filtration resistances coincided with lower extracellular polymeric substances concentration in the bulk sludge at SRT of 40 days, likely resulting in a decreased particle flocculation. Results showed that dynamic membrane technology achieved a stable and high quality permeate and AnDMBRs can be used as a reliable and satisfactory technology for treatment of high strength wastewaters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Effects of filtration modes on membrane fouling behavior and treatment in submerged membrane bioreactor.

PubMed

Maqbool, Tahir; Khan, Sher Jamal; Lee, Chung-Hak

2014-11-01

Relaxation or backwashing is obligatory for effective operation of membrane module and intermittent aeration is helpful for nutrients removal. This study was performed to investigate effects of different filtration modes on membrane fouling behavior and treatment in membrane bioreactor (MBR) operated at three modes i.e., 12, 10 and 8min filtration and 3, 2, and 2min relaxation corresponding to 6, 5 and 4cycles/hour, respectively. Various parameters including trans-membrane pressure, specific cake resistance, specific oxygen uptake rate, nutrients removal and sludge dewaterability were examined to optimize the filtration mode. TMP profiles showed that MBR(8+2) with 8min filtration and 2min relaxation reduced the fouling rate and depicted long filtration time in MBR treating synthetic wastewater. MBR(12+3) was more efficient in organic and nutrients removal while denitrification rate was high in MBR(8+2). Copyright © 2014 Elsevier Ltd. All rights reserved.

Computational Fluid Dynamics of Choanoflagellate Filter-Feeding

NASA Astrophysics Data System (ADS)

Asadzadeh, Seyed Saeed; Walther, Jens; Nielsen, Lasse Tore; Kiorboe, Thomas; Dolger, Julia; Andersen, Anders

2017-11-01

Choanoflagellates are unicellular aquatic organisms with a single flagellum that drives a feeding current through a funnel-shaped collar filter on which bacteria-sized prey are caught. Using computational fluid dynamics (CFD) we model the beating flagellum and the complex filter flow of the choanoflagellate Diaphanoeca grandis. Our CFD simulations based on the current understanding of the morphology underestimate the experimentally observed clearance rate by more than an order of magnitude: The beating flagellum is simply unable to draw enough water through the fine filter. Our observations motivate us to suggest a radically different filtration mechanism that requires a flagellar vane (sheet), and addition of a wide vane in our CFD model allows us to correctly predict the observed clearance rate.

Associations of estimated glomerular filtration rate and albuminuria with mortality and renal failure by sex: a meta-analysis.

PubMed

Nitsch, Dorothea; Grams, Morgan; Sang, Yingying; Black, Corri; Cirillo, Massimo; Djurdjev, Ognjenka; Iseki, Kunitoshi; Jassal, Simerjot K; Kimm, Heejin; Kronenberg, Florian; Oien, Cecilia M; Levey, Andrew S; Levin, Adeera; Woodward, Mark; Hemmelgarn, Brenda R

2013-01-29

To assess for the presence of a sex interaction in the associations of estimated glomerular filtration rate and albuminuria with all-cause mortality, cardiovascular mortality, and end stage renal disease. Random effects meta-analysis using pooled individual participant data. 46 cohorts from Europe, North and South America, Asia, and Australasia. 2,051,158 participants (54% women) from general population cohorts (n=1,861,052), high risk cohorts (n=151,494), and chronic kidney disease cohorts (n=38,612). Eligible cohorts (except chronic kidney disease cohorts) had at least 1000 participants, outcomes of either mortality or end stage renal disease of ≥ 50 events, and baseline measurements of estimated glomerular filtration rate according to the Chronic Kidney Disease Epidemiology Collaboration equation (mL/min/1.73 m(2)) and urinary albumin-creatinine ratio (mg/g). Risks of all-cause mortality and cardiovascular mortality were higher in men at all levels of estimated glomerular filtration rate and albumin-creatinine ratio. While higher risk was associated with lower estimated glomerular filtration rate and higher albumin-creatinine ratio in both sexes, the slope of the risk relationship for all-cause mortality and for cardiovascular mortality were steeper in women than in men. Compared with an estimated glomerular filtration rate of 95, the adjusted hazard ratio for all-cause mortality at estimated glomerular filtration rate 45 was 1.32 (95% CI 1.08 to 1.61) in women and 1.22 (1.00 to 1.48) in men (P(interaction)<0.01). Compared with a urinary albumin-creatinine ratio of 5, the adjusted hazard ratio for all-cause mortality at urinary albumin-creatinine ratio 30 was 1.69 (1.54 to 1.84) in women and 1.43 (1.31 to 1.57) in men (P(interaction)<0.01). Conversely, there was no evidence of a sex difference in associations of estimated glomerular filtration rate and urinary albumin-creatinine ratio with end stage renal disease risk. Both sexes face increased risk of all-cause mortality, cardiovascular mortality, and end stage renal disease with lower estimated glomerular filtration rates and higher albuminuria. These findings were robust across a large global consortium.

Temporary renal ischemia during nephron sparing surgery is associated with short-term but not long-term impairment in renal function.

PubMed

Yossepowitch, Ofer; Eggener, Scott E; Serio, Angel; Huang, William C; Snyder, Mark E; Vickers, Andrew J; Russo, Paul

2006-10-01

The emergence of laparoscopic nephron sparing surgery has rekindled interest in the impact of warm renal ischemia on renal function. To provide data with which warm renal ischemia can be compared we analyzed short-term and long-term changes in the glomerular filtration rate after temporary cold renal ischemia. In patients undergoing open nephron sparing surgery the estimated glomerular filtration rate was assessed preoperatively, early in the postoperative hospital stay, and 1 and 12 months after surgery using the abbreviated Modification of Diet in Renal Disease Study equation. We separately analyzed 70 patients with a solitary kidney and 592 with 2 functioning kidneys. The end point was the percent change from the baseline glomerular filtration rate. A linear regression model was used to test the association between the glomerular filtration rate change, and ischemia time, patient age, tumor size, estimated blood loss and intraoperative fluid administration. Median cold ischemia time was 31 minutes in patients with a solitary kidney and 35 minutes in those with 2 kidneys. Compared to patients with 2 kidneys those with a solitary kidney had a significantly lower preoperative estimated glomerular filtration rate (p < 0.001), which decreased a median of 30% during the early postoperative period, and 15% and 32% 1 and 12 months after surgery, respectively. In patients with 2 kidneys the corresponding glomerular filtration rate decreases were 16%, 13% and 14%, respectively. On multivariate analyses in each group cold ischemia duration and intraoperative blood loss were significantly associated with early glomerular filtration rate changes. However, 12 months after surgery age was the only independent predictor of a glomerular filtration rate decrease in patients with 2 kidneys. Cold renal ischemia during nephron sparing surgery is a significant determinant of the short-term postoperative glomerular filtration rate. Longer clamping time is particularly detrimental in patients with a solitary kidney but it does not appear to influence long-term renal function. Patients of advanced age may be less likely to recover from acute ischemic renal injury.

Sterile Filtration of Highly Concentrated Protein Formulations: Impact of Protein Concentration, Formulation Composition, and Filter Material.

PubMed

Allmendinger, Andrea; Mueller, Robert; Huwyler, Joerg; Mahler, Hanns-Christian; Fischer, Stefan

2015-10-01

Differences in filtration behavior of concentrated protein formulations were observed during aseptic drug product manufacturing of biologics dependent on formulation composition. The present study investigates filtration forces of monoclonal antibody formulations in a small-scale set-up using polyvinylidene difluoride (PVDF) or polyethersulfone (PES) filters. Different factors like formulation composition and protein concentration related to differences in viscosity, as well as different filtration rates were evaluated. The present study showed that filtration behavior was influenced by the presence or absence of a surfactant in the formulation, which defines the interaction between filter membrane and surface active formulation components. This can lead to a change in filter resistance (PES filter) independent on the buffer system used. Filtration behavior was additionally defined by rheological non-Newtonian flow behavior. The data showed that high shear rates resulting from small pore sizes and filtration pressure up to 1.0 bar led to shear-thinning behavior for highly concentrated protein formulations. Differences in non-Newtonian behavior were attributed to ionic strength related to differences in repulsive and attractive interactions. The present study showed that the interplay of formulation composition, filter material, and filtration rate can explain differences in filtration behavior/filtration flux observed for highly concentrated protein formulations thus guiding filter selection. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

Technical characterization of dialysis fluid flow and mass transfer rate in dialyzers with various filtration coefficients using dimensionless correlation equation.

PubMed

Fukuda, Makoto; Yoshimura, Kengo; Namekawa, Koki; Sakai, Kiyotaka

2017-06-01

The objective of the present study is to evaluate the effect of filtration coefficient and internal filtration on dialysis fluid flow and mass transfer coefficient in dialyzers using dimensionless mass transfer correlation equations. Aqueous solution of vitamin B 12 clearances were obtained for REXEED-15L as a low flux dialyzer, and APS-15EA and APS-15UA as high flux dialyzers. All the other design specifications were identical for these dialyzers except for filtration coefficient. The overall mass transfer coefficient was calculated, moreover, the exponents of Reynolds number (Re) and film mass transfer coefficient of the dialysis-side fluid (k D ) for each flow rate were derived from the Wilson plot and dimensionless correlation equation. The exponents of Re were 0.4 for the low flux dialyzer whereas 0.5 for the high flux dialyzers. Dialysis fluid of the low flux dialyzer was close to laminar flow because of its low filtration coefficient. On the other hand, dialysis fluid of the high flux dialyzers was assumed to be orthogonal flow. Higher filtration coefficient was associated with higher k D influenced by mass transfer rate through diffusion and internal filtration. Higher filtration coefficient of dialyzers and internal filtration affect orthogonal flow of dialysis fluid.

Creatinine Clearance Is Not Equal to Glomerular Filtration Rate and Cockcroft-Gault Equation Is Not Equal to CKD-EPI Collaboration Equation.

PubMed

Fernandez-Prado, Raul; Castillo-Rodriguez, Esmeralda; Velez-Arribas, Fernando Javier; Gracia-Iguacel, Carolina; Ortiz, Alberto

2016-12-01

Direct oral anticoagulants (DOACs) may require dose reduction or avoidance when glomerular filtration rate is low. However, glomerular filtration rate is not usually measured in routine clinical practice. Rather, equations that incorporate different variables use serum creatinine to estimate either creatinine clearance in mL/min or glomerular filtration rate in mL/min/1.73 m 2 . The Cockcroft-Gault equation estimates creatinine clearance and incorporates weight into the equation. By contrast, the Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations estimate glomerular filtration rate and incorporate ethnicity but not weight. As a result, an individual patient may have very different renal function estimates, depending on the equation used. We now highlight these differences and discuss the impact on routine clinical care for anticoagulation to prevent embolization in atrial fibrillation. Pivotal DOAC clinical trials used creatinine clearance as a criterion for patient enrollment, and dose adjustment and Federal Drug Administration recommendations are based on creatinine clearance. However, clinical biochemistry laboratories provide CKD-EPI glomerular filtration rate estimations, resulting in discrepancies between clinical trial and routine use of the drugs. Copyright © 2016 Elsevier Inc. All rights reserved.

Validation of serum free light chain reference ranges in primary care.

PubMed

Galvani, Luca; Flanagan, Jane; Sargazi, Mansour; Neithercut, William D

2016-05-01

The demand for measurement of serum immunoglobulin free kappa (κ) and lambda (λ) light chains has increased. The κ:λ ratio is used to assist in diagnosis/monitoring of plasma cell disorders. The binding site reference range for serum-free light chain κ:λ ratios of 0.26-1.65 was derived from healthy volunteers. Subsequently, a reference range of 0.37-3.1 for patients with chronic kidney disease has been proposed. Elevated free light chain concentrations and borderline raised free light chain ratios also may be found in polyclonal gammopathies and with other non-renal illnesses. This assessment was conducted to validate the established free light chain reference ranges in individuals from primary care. A total of 130 samples were identified from routine blood samples collected in primary care for routine biochemistry testing and estimated glomerular filtration rate calculation. The median and range of κ:λ ratios found in each estimated glomerular filtration rate group used for chronic kidney disease classification were higher than previously described. This was the case for individuals with normal or essentially normal renal function with estimated glomerular filtration rates>90, (0.58-1.76) and estimated glomerular filtration rate of 60-90 mL/min/1.73 m(2), (0.71-1.93). Individuals with estimated glomerular filtration rate 15-30, (0.72-4.50) and estimated glomerular filtration rate <15 ml/min/1.73 m(2) (0.71-4.95) also had higher values when compared to the current renal reference range of 0.37-3.10. Elevation of free light chain-κ:λ ratios may occur in the absence of a reduced renal function shown by a normal estimated glomerular filtration rate and in the presence of reduced renal function by estimated glomerular filtration rate when comparing results with the established reference ranges. Explanations include choice of analytical systems or the presence of other concurrent non-plasma cell illness. © The Author(s) 2016.

Evaluation of various harvesting methods for high-density microalgae, Aurantiochytrium sp. KRS101.

PubMed

Kim, Kyochan; Shin, Heewon; Moon, Myounghoon; Ryu, Byung-Gon; Han, Jong-In; Yang, Ji-Won; Chang, Yong Keun

2015-12-01

Five technologies, coagulation, electro-flotation (EF), electro-coagulation-flotation (ECF), centrifugation, and membrane filtration, were systematically assessed for their adequacy of harvesting Aurantiochytrium sp. KRS101, a heterotrophic microalgal species that has much higher biomass concentration than photoautotrophic species. Coagulation, EF, and ECF were found to have limited efficiency. Centrifugation was overly powerful to susceptible cells like Aurantiochytrium sp. KRS101, inducing cell rupture and consequently biomass loss of over 13%. Membrane filtration, in particular equipped with an anti-fouling turbulence generator, turned out to be best suited: nearly 100% of harvesting efficiency and low water content in harvested biomass were achieved. With rotation rate increased, high permeate fluxes could be attained even with extremely concentrated biomass: e.g., 219.0 and 135.0 L/m(2)/h at 150.0 and 203.0 g/L, respectively. Dynamic filtration appears to be indeed a suitable means especially to obtain highly concentrated biomass that have no need of dewatering and can be directly processed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of the rate of filtration of a complexly alloyed nickel melt through a foam-ceramic filter on the sulfur impurity content in the metal

NASA Astrophysics Data System (ADS)

Sidorov, V. V.; Min, P. G.; Folomeikin, Yu. I.; Vadeev, V. E.

2015-06-01

The article discusses the possibility of additional refining of a complexly alloyed nickel melt from a sulfur impurity by decreasing the filtration rate during the passage of the melt through a foam-ceramic filter. The degree of sulfur removal from the melt is shown to depend on its content in the alloy and the melt filtration rate.

Evaluation of emerging factors blocking filtration of high-adjunct-ratio wort.

PubMed

Ma, Ting; Zhu, Linjiang; Zheng, Feiyun; Li, Yongxian; Li, Qi

2014-08-20

Corn starch has become a common adjunct for beer brewing in Chinese breweries. However, with increasing ratio of corn starch, problems like poor wort filtration performance arise, which will decrease production capacity of breweries. To solve this problem, factors affecting wort filtration were evaluated, such as the size of corn starch particle, special yellow floats formed during liquefaction of corn starch, and residual substance after liquefaction. The effects of different enzyme preparations including β-amylase and β-glucanase on filtration rate were also evaluated. The results indicate that the emerging yellow floats do not severely block filtration, while the fine and uniform-shape corn starch particle and its incompletely hydrolyzed residue after liquefaction are responsible for filtration blocking. Application of β-amylase preparation increased the filtration rate of liquefied corn starch. This study is useful for our insight into the filtration blocking problem arising in the process of high-adjunct-ratio beer brewing and also provides a feasible solution using enzyme preparations.

Measurement of Murine Single-Kidney Glomerular Filtration Rate Using Dynamic Contrast-Enhanced MRI.

PubMed

Jiang, Kai; Tang, Hui; Mishra, Prasanna K; Macura, Slobodan I; Lerman, Lilach O

2018-06-01

To develop and validate a method for measuring murine single-kidney glomerular filtration rate (GFR) using dynamic contrast-enhanced MRI (DCE-MRI). This prospective study was approved by the Institutional Animal Care and Use Committee. A fast longitudinal relaxation time (T 1 ) measurement method was implemented to capture gadolinium dynamics (1 s/scan), and a modified two-compartment model was developed to quantify GFR as well as renal perfusion using 16.4T MRI in mice 2 weeks after unilateral renal artery stenosis (RAS, n = 6) or sham (n = 8) surgeries. This approach was validated by comparing model-derived GFR and perfusion to those obtained by fluorescein isothiocyanante (FITC)-inulin clearance and arterial spin labeling (ASL), respectively, using the Pearson's and Spearman's rank correlations and Bland-Altman analysis. The compartmental model provided a good fitting to measured gadolinium dynamics in both normal and RAS kidneys. The proposed DCE-MRI method offered assessment of single-kidney GFR and perfusion, comparable to the FITC-inulin clearance (Pearson's correlation coefficient r = 0.95 and Spearman's correlation coefficient ρ = 0.94, P < 0.0001, and mean difference -7.0 ± 11.0 μL/min) and ASL (r = 0.92 and ρ = 0.84, P < 0.0001, and mean difference 4.4 ± 66.1 mL/100 g/min) methods. The proposed DCE-MRI method may be useful for reliable noninvasive measurements of single-kidney GFR and perfusion in mice. Magn Reson Med 79:2935-2943, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

Associations of estimated glomerular filtration rate and albuminuria with mortality and renal failure by sex: a meta-analysis

PubMed Central

Nitsch, Dorothea; Grams, Morgan; Sang, Yingying; Black, Corri; Cirillo, Massimo; Djurdjev, Ognjenka; Iseki, Kunitoshi; Jassal, Simerjot K; Kimm, Heejin; Kronenberg, Florian; Øien, Cecilia M; Levin, Adeera; Woodward, Mark; Hemmelgarn, Brenda R

2013-01-01

Objective To assess for the presence of a sex interaction in the associations of estimated glomerular filtration rate and albuminuria with all-cause mortality, cardiovascular mortality, and end stage renal disease. Design Random effects meta-analysis using pooled individual participant data. Setting 46 cohorts from Europe, North and South America, Asia, and Australasia. Participants 2 051 158 participants (54% women) from general population cohorts (n=1 861 052), high risk cohorts (n=151 494), and chronic kidney disease cohorts (n=38 612). Eligible cohorts (except chronic kidney disease cohorts) had at least 1000 participants, outcomes of either mortality or end stage renal disease of ≥50 events, and baseline measurements of estimated glomerular filtration rate according to the Chronic Kidney Disease Epidemiology Collaboration equation (mL/min/1.73 m2) and urinary albumin-creatinine ratio (mg/g). Results Risks of all-cause mortality and cardiovascular mortality were higher in men at all levels of estimated glomerular filtration rate and albumin-creatinine ratio. While higher risk was associated with lower estimated glomerular filtration rate and higher albumin-creatinine ratio in both sexes, the slope of the risk relationship for all-cause mortality and for cardiovascular mortality were steeper in women than in men. Compared with an estimated glomerular filtration rate of 95, the adjusted hazard ratio for all-cause mortality at estimated glomerular filtration rate 45 was 1.32 (95% CI 1.08 to 1.61) in women and 1.22 (1.00 to 1.48) in men (Pinteraction<0.01). Compared with a urinary albumin-creatinine ratio of 5, the adjusted hazard ratio for all-cause mortality at urinary albumin-creatinine ratio 30 was 1.69 (1.54 to 1.84) in women and 1.43 (1.31 to 1.57) in men (Pinteraction<0.01). Conversely, there was no evidence of a sex difference in associations of estimated glomerular filtration rate and urinary albumin-creatinine ratio with end stage renal disease risk. Conclusions Both sexes face increased risk of all-cause mortality, cardiovascular mortality, and end stage renal disease with lower estimated glomerular filtration rates and higher albuminuria. These findings were robust across a large global consortium. PMID:23360717

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyamori, I.; Yasuhara, S.; Takeda, Y.

The effects of captopril on effective renal plasma flow and glomerular filtration rate were studied using a noninvasive radioisotopic method on individual kidneys in eight patients with renovascular hypertension and 12 patients with essential hypertension with various renin levels. Four patients with renovascular hypertension had unilateral while three had bilateral renal artery stenosis. The effective renal plasma flow and glomerular filtration rate were determined by using /sup 131/I-iodohippurate sodium and /sup 99m/Tc-diethylenetriamine pentaacetic acid, respectively. Glomerular filtration rate and effective renal plasma flow were significantly reduced in the stenotic kidneys of patients with renovascular hypertension compared with values in nonstenoticmore » kidneys (p less than 0.01). Treatment with captopril, 37.5 to 75 mg/day for 1 to 48 weeks, further reduced the glomerular filtration rate only in stenotic kidneys, and effective renal plasma flow increased in both kidney types. In two of the three renal hypertensive patients with bilateral renal artery stenosis, captopril produced a reversible azotemia that was unrelated to the fall in blood pressure, as evidenced by the lack of azotemia seen after a moderate blood pressure reduction induced by other antihypertensive medications. These results indicate that endogenous angiotensin II is essential in maintaining the glomerular filtration rate in stenotic kidneys and suggest that a reduction in glomerular filtration rate during captopril administration could indicate the presence of renal artery stenosis.« less

Membrane filtration method for enumeration and isolation of Alicyclobacillus spp. from apple juice.

PubMed

Lee, S-Y; Chang, S-S; Shin, J-H; Kang, D-H

2007-11-01

To evaluate the applicability of filtration membranes for detecting Alicyclobacillus spp. spores in apple juice. Ten types of nitrocellulose membrane filters from five manufacturers were used to collect and enumerate five Alicyclobacillus spore isolates and results were compared to conventional K agar plating. Spore recovery differed among filters with an average recovery rate of 126.2%. Recovery levels also differed among spore isolates. Although significant difference (P < 0.05) in spore sizes existed, no correlation could be determined between spore size and membrane filter recovery rate. Recovery of spores using membrane filtration is dependent on the manufacturer and filter pore size. Correlations between spore recovery rate and spore size could not be determined. Low numbers of Alicyclobacillus spores in juice can be effectively detected using membrane filtration although recovery rate differences exist among different manufacturers. Use of membrane filtration is a simple, fast alternative to the week-long enrichment procedures currently employed in most quality assurance tests.

Quantifying the size-resolved dynamics of indoor bioaerosol transport and control.

PubMed

Kunkel, S A; Azimi, P; Zhao, H; Stark, B C; Stephens, B

2017-09-01

Understanding the bioaerosol dynamics of droplets and droplet nuclei emitted during respiratory activities is important for understanding how infectious diseases are transmitted and potentially controlled. To this end, we conducted experiments to quantify the size-resolved dynamics of indoor bioaerosol transport and control in an unoccupied apartment unit operating under four different HVAC particle filtration conditions. Two model organisms (Escherichia coli K12 and bacteriophage T4) were aerosolized under alternating low and high flow rates to roughly represent constant breathing and periodic coughing. Size-resolved aerosol sampling and settle plate swabbing were conducted in multiple locations. Samples were analyzed by DNA extraction and quantitative polymerase chain reaction (qPCR). DNA from both organisms was detected during all test conditions in all air samples up to 7 m away from the source, but decreased in magnitude with the distance from the source. A greater fraction of T4 DNA was recovered from the aerosol size fractions smaller than 1 μm than E. coli K12 at all air sampling locations. Higher efficiency HVAC filtration also reduced the amount of DNA recovered in air samples and on settle plates located 3-7 m from the source. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Static and dynamic removal of aquatic natural organic matter by carbon nanotubes.

PubMed

Ajmani, Gaurav S; Cho, Hyun-Hee; Abbott Chalew, Talia E; Schwab, Kellogg J; Jacangelo, Joseph G; Huang, Haiou

2014-08-01

Carbon nanotubes (CNTs) were investigated for their capability and mechanisms to simultaneously remove colloidal natural organic matter (NOM) and humic substances from natural surface water. Static removal testing was conducted via adsorption experiments while dynamic removal was evaluated by layering CNTs onto substrate membranes and filtering natural water through the CNT-layered membranes. Analyses of treated water samples showed that removal of humic substances occurred via adsorption under both static and dynamic conditions. Removal of colloidal NOM occurred at a moderate level of 36-66% in static conditions, independent of the specific surface area (SSA) of CNTs. Dynamic removal of colloidal NOM increased from approximately 15% with the unmodified membrane to 80-100% with the CNT-modified membranes. Depth filtration played an important role in colloidal NOM removal. A comparison of the static and dynamic removal of humic substances showed that equilibrium static removal was higher than dynamic (p < 0.01), but there was also a significant linear relationship between static and dynamic removal (p < 0.05). Accounting for contact time of CNTs with NOM during filtration, it appeared that CNT mat structure was an important determinant of removal efficiencies for colloidal NOM and humic substances during CNT membrane filtration. Copyright © 2014 Elsevier Ltd. All rights reserved.

Performance of the chronic kidney disease-epidemiology study equations for estimating glomerular filtration rate before and after nephrectomy.

PubMed

Lane, Brian R; Demirjian, Sevag; Weight, Christopher J; Larson, Benjamin T; Poggio, Emilio D; Campbell, Steven C

2010-03-01

Accurate renal function determination before and after nephrectomy is essential for proper prevention and management of chronic kidney disease due to nephron loss and ischemic injury. We compared the estimated glomerular filtration rate using several serum creatinine based formulas against the measured rate based on (125)I-iothalamate clearance to determine which most accurately reflects the rate in this setting. Of 7,611 patients treated at our institution since 1975 the measured glomerular filtration rate was selectively determined before and after nephrectomy in 268 and 157, respectively. Performance of the Cockcroft-Gault, Modification of Diet in Renal Disease Study, re-expressed Modification of Diet in Renal Disease Study and Chronic Kidney Disease-Epidemiology Study equations, each of which estimates the glomerular filtration rate, were determined using serum creatinine, age, gender, weight and body surface area. The performance of serum creatinine, reciprocal serum creatinine and the 4 formulas was compared with the measured rate using Pearson's correlation, Lin's concordance coefficient and residual plots. Median serum creatinine was 1.4 mg/dl and the median measured glomerular filtration rate was 50 ml per minute per 1.73 m(2). The correlation between serum creatinine and the measured rate was poor (-0.66) compared with that of reciprocal serum creatinine (0.78) and the 4 equations (0.82 to 0.86). The Chronic Kidney Disease-Epidemiology Study equation performed with greatest precision and accuracy, and least bias of all equations. Stage 3 or greater chronic kidney disease ((125)I-iothalamate glomerular filtration rate 60 ml per minute per 1.73 m(2) or less) was present in 44% of patients with normal serum creatinine (1.4 mg/dl or less) postoperatively. Such missed diagnoses of chronic kidney disease decreased 42% using the Chronic Kidney Disease-Epidemiology Study equation. Glomerular filtration rate estimation equations outperform serum creatinine and better identify patients with perinephrectomy compromised renal function. The newly developed, serum creatinine based, Chronic Kidney Disease-Epidemiology Study equation has sufficient accuracy to render direct glomerular filtration rate measurement unnecessary before and after nephrectomy for cause in most circumstances. 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Insulin induces the correlation between renal blood flow and glomerular filtration rate in diabetes: implications for mechanisms causing hyperfiltration.

PubMed

Pihl, Liselotte; Persson, Patrik; Fasching, Angelica; Hansell, Peter; DiBona, Gerald F; Palm, Fredrik

2012-07-01

Glomerular filtration rate (GFR) and renal blood flow (RBF) are normally kept constant via renal autoregulation. However, early diabetes results in increased GFR and the potential mechanisms are debated. Tubuloglomerular feedback (TGF) inactivation, with concomitantly increased RBF, is proposed but challenged by the finding of glomerular hyperfiltration in diabetic adenosine A(1) receptor-deficient mice, which lack TGF. Furthermore, we consistently find elevated GFR in diabetes with only minor changes in RBF. This may relate to the use of a lower streptozotocin dose, which produces a degree of hyperglycemia, which is manageable without supplemental suboptimal insulin administration, as has been used by other investigators. Therefore, we examined the relationship between RBF and GFR in diabetic rats with (diabetes + insulin) and without suboptimal insulin administration (untreated diabetes). As insulin can affect nitric oxide (NO) release, the role of NO was also investigated. GFR, RBF, and glomerular filtration pressures were measured. Dynamic RBF autoregulation was examined by transfer function analysis between arterial pressure and RBF. Both diabetic groups had increased GFR (+60-67%) and RBF (+20-23%) compared with controls. However, only the diabetes + insulin group displayed a correlation between GFR and RBF (R(2) = 0.81, P < 0.0001). Net filtration pressure was increased in untreated diabetes compared with both other groups. The difference between untreated and insulin-treated diabetic rats disappeared after administering N(ω)-nitro-l-arginine methyl ester to inhibit NO synthase and subsequent NO release. In conclusion, mechanisms causing diabetes-induced glomerular hyperfiltration are animal model-dependent. Supplemental insulin administration results in a RBF-dependent mechanism, whereas elevated GFR in untreated diabetes is mediated primarily by a tubular event. Insulin-induced NO release partially contributes to these differences.

Measurement of glomerular filtration rate using dynamic magnetic resonance imaging in patients with chronic kidney disease.

PubMed

Artunc, Ferruh; Yildiz, Serdar; Boss, Andreas; Frenzel, Thomas; Schlemmer, Heinz-Peter; Schick, Fritz; Risler, Teut; Häring, Hans-Ulrich; Rossi, Cristina

2011-01-01

Determination of glomerular filtration rate (GFR) using plasma disappearance curves requires the injection of a filtration marker and repeated timed blood collections. Gadolinium-containing contrast media are excreted exclusively by glomerular filtration and could provide a novel approach to quantifying GFR using magnetic resonance (MR) imaging. The aim of this study was to demonstrate the feasibility of measuring GFR by the clearance of gadolinium-containing contrast medium in patients with chronic kidney disease (CKD). Informed consent was obtained from stable CKD patients in stages 1, 2 or 3 (n=16; 5 women, 11 men; median age 54 years). GFR was measured after a bolus injection of gadobutrol (4 mL, approximately 0.05 mmol/kg) and calculated from the washout of the signal intensity obtained over the liver. The obtained MR-GFR was compared with simultaneously measured plasma clearance of inulin and gadobutrol. Technical failure occurred in 2 patients. The mean obtained MR-GFR was 71 ± 25 (SD) mL/min per 1.73 m² and agreed well with the mean inulin-GFR (70 ± 24 mL/min per 1.73 m²). Pearson's correlation coefficient was r=0.91. The mean of the paired differences was 1 ± 10 mL/min per 1.73 m² and not significantly different from zero. GFR obtained from gadobutrol plasma clearance also agreed well with inulin-GFR and MR-GFR (r=0.92 and r=0.75, respectively). We describe a novel method of determining GFR from MR imaging using a low dose of gadobutrol in patients with reduced GFR that enables the absolute quantification of GFR after routine contrast-enhanced MR imaging.

Dynamic Optical Filtration

NASA Technical Reports Server (NTRS)

Chretien, Jean-Loup (Inventor); Lu, Edward T. (Inventor)

2005-01-01

A dynamic optical filtration system and method effectively blocks bright light sources without impairing view of the remainder of the scene. A sensor measures light intensity and position so that selected cells of a shading matrix may interrupt the view of the bright light source by a receptor. A beamsplitter may be used so that the sensor may be located away from the receptor. The shading matrix may also be replaced by a digital micromirror device, which selectively sends image data to the receptor.

Dynamic optical filtration

NASA Technical Reports Server (NTRS)

Chretien, Jean-Loup (Inventor); Lu, Edward T. (Inventor)

2005-01-01

A dynamic optical filtration system and method effectively blocks bright light sources without impairing view of the remainder of the scene. A sensor measures light intensity and position so that selected cells of a shading matrix may interrupt the view of the bright light source by a receptor. A beamsplitter may be used so that the sensor may be located away from the receptor. The shading matrix may also be replaced by a digital micromirror device, which selectively sends image data to the receptor.

Measurement of filtration rates by infaunal bivalves in a recirculating flume

USGS Publications Warehouse

Cole, B.E.; Thompson, J.K.; Cloern, J.E.

1992-01-01

A flume system and protocol for measuring the filtration rate of infaunal bivalves is described. Assemblages of multi-sized clams, at natural densities and in normal filter-feeding positions, removed phytoplankton suspended in a unidirectional flow of water. The free-stream velocity and friction velocity of the flow, and bottom roughness height were similar to those in natural estuarine waters. Continuous variations in phytoplankton (Chroomonas salinay) cell density were used to measure the filtration rate of the suspension-feeding clam Potamocorbula amurensis for periods of 2 to 28 h. Filtration rates of P. amurensis varied from 100 to 580 liters (gd)-1 over a free-stream velocity range of 9 to 25 cm s-1. Phytoplankton loss rates were usually constant throughout the experiments. Our results suggest that suspension-feeding by infaunal bivalves is sensitive to flow velocity. ?? 1992 Springer-Verlag.

Effect of Fusarium isolates and their filtrates on respiratory rate and chemical analysis of squash plants.

PubMed

El-Shenawy, Z; Mansour, M A; El-Behrawi, S

1978-01-01

The highly pathogenic isolate stimulated the emergence of the squash seedlings first, caused, however, the highest death rate of the seedlings finally. Fusarium isolates and their culture filtrates inhibited the respiratory rate of squash plants significantly. However, F. oxysporum isolates inhibited respiration more than F. solani isolates. Seasonal changes of respiration decline show that the respiratory rate decreased with plant growth in the case of infested soil and of plants injected with culture filtrates. However, spraying Fusarium culture filtrates on the foliage gave opposite results when the plants grew older. Fusarium solani isolates decreased nitrogen content of squash stems and leaves, while F. oxysporum isolates gave reverse results. Injecting Fusarium culture filtrate into the plant decreased nitrogen content of both stems and leaves, while spraying the foliage with the filtrates increased nitrogen content more than that of the control. Phosphorus content of the stems of squash plants, sown in infested soil, was less than in the control when the plants were treated with F. solani and higher when they were treated with F. oxysporum isolates. On the other hand, the phosphorus content of squash leaves was higher than in the control. In the case of injected plants, however, the phosphorus content in stems and leaves was equal to that of the control or less, and with sprayed plants it was higher than in the control. Infesting the soil with Fusarium isolates and spraying the foliage with their culture filtrates increased potassium content of squash stems and leaves, while injecting the filtrates into the plants decreased potassium content of both stems and leaves.

27. Detail view of mechanical float gages used to monitor ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

27. Detail view of mechanical float gages used to monitor level of water in the filtration bed reservoir. Gage on left measures water head, gage on right monitors filtration rate. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

Assessment of glomerular filtration rate and effective renal plasma flow in cystic fibrosis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spino, M.; Chai, R.P.; Isles, A.F.

1985-07-01

A study was conducted to examine renal function in 10 healthy control subjects and eight patients with cystic fibrosis in stable condition. Sequential bolus injections of /sup 99m/Tc-DTPA and /sup 125/I-OIH were administered to assess glomerular filtration rate and effective renal plasma flow, respectively. Blood was subsequently collected for 3 hours, and urine for 24 hours. Renal clearances of both radioisotope markers were virtually identical in patients and controls. Inasmuch as neither glomerular filtration rate nor effective renal plasma flow was enhanced in patients with cystic fibrosis, increased clearance of drugs in these patients is unlikely to be the resultmore » of enhanced glomerular filtration or tubular secretion.« less

Enhanced performance of crumb rubber filtration for ballast water treatment.

PubMed

Tang, Zhijian; Butkus, Michael A; Xie, Yuefeng F

2009-03-01

Waste-tire-derived crumb rubber was utilized as filter media to develop an efficient filter for ballast water treatment. In this study, the effects of coagulation, pressure filtration and dual-media (gravity) filtration on the performance of the crumb rubber filtration were investigated. The removal efficiencies of turbidity, phytoplankton and zooplankton, and head loss development were monitored during the filtration process. The addition of a coagulant enhanced the removal efficiencies of all targeted matter, but resulted in substantial increase of head loss. Pressure filtration increased filtration rates to 220 m(3)h(-1)m(-2) for 8-h operation and improved the zooplankton removal. Dual-media (crumb rubber/sand) gravity filtration also improved the removal efficiencies of phytoplankton and zooplankton over mono-media gravity crumb rubber filtration. However, these filtration techniques alone did not meet the criteria for removing indigenous organisms from ballast water. A combination of filtration and disinfection is suggested for future studies.

Chronic Kidney Disease Epidemiology Collaboration versus Modification of Diet in Renal Disease equations for renal function evaluation in patients undergoing partial nephrectomy.

PubMed

Shikanov, Sergey; Clark, Melanie A; Raman, Jay D; Smith, Benjamin; Kaag, Matthew; Russo, Paul; Wheat, Jeffrey C; Wolf, J Stuart; Huang, William C; Shalhav, Arieh L; Eggener, Scott E

2010-11-01

A novel equation, the Chronic Kidney Disease Epidemiology Collaboration, has been proposed to replace the Modification of Diet in Renal Disease for estimated glomerular filtration rate due to higher accuracy, particularly in the setting of normal renal function. We compared these equations in patients with 2 functioning kidneys undergoing partial nephrectomy. We assembled a cohort of 1,158 patients from 5 institutions who underwent partial nephrectomy between 1991 and 2009. Only subjects with 2 functioning kidneys were included in the study. The end points were baseline estimated glomerular filtration rate, last followup estimated glomerular filtration rate (3 to 18 months), absolute and percent change estimated glomerular filtration rate ([absolute change/baseline] × 100%), and proportion of newly developed chronic kidney disease stage III. The agreement between the equations was evaluated using Bland-Altman plots and the McNemar test for paired observations. Mean baseline estimated glomerular filtration rate derived from the Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration equations were 73 and 77 ml/minute/1.73 m(2), respectively, and following surgery were 63 and 67 ml/minute/1.73 m(2), respectively. Mean percent change estimated glomerular filtration rate was -12% for both equations (p = 0.2). The proportion of patients with newly developed chronic kidney disease stage III following surgery was 32% and 25%, according to the Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration equations, respectively (p = 0.001). For patients with 2 functioning kidneys undergoing partial nephrectomy the Chronic Kidney Disease Epidemiology Collaboration equation provides slightly higher glomerular filtration rate estimates compared to the Modification of Diet in Renal Disease equation, with 7% fewer patients categorized as having chronic kidney disease stage III or worse. Copyright © 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Filtration effects on ball bearing life and condition in a contaminated lubricant

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Moyer, D. W.

1978-01-01

Ball bearings were fatigue tested with a noncontaminated lubricant and with a contaminated lubricant under four levels of filtration. The test filters had absolute particle removal ratings of 3, 30, 49, and 105 microns. Aircraft turbine engine contaminants were injected into the filter's supply line at a constant rate of 125 milligrams per bearing hour. Bearing life and running track condition generally improved with finer filtration. The experimental lives of 3 and 30 micron filter bearings were statistically equivalent, approaching those obtained with the noncontaminated lubricant bearings. Compared to these bearings, the lives of the 49 micron bearings were statistically lower. The 105 micron bearings experienced gross wear. The degree of surface distress, weight loss, and probable failure mode were dependent on filtration level, with finer filtration being clearly beneficial.

Nocturnal polyuria is related to absent circadian rhythm of glomerular filtration rate.

PubMed

De Guchtenaere, A; Vande Walle, C; Van Sintjan, P; Raes, A; Donckerwolcke, R; Van Laecke, E; Hoebeke, P; Vande Walle, J

2007-12-01

Monosymptomatic nocturnal enuresis is frequently associated with nocturnal polyuria and low urinary osmolality during the night. Initial studies found decreased vasopressin levels associated with low urinary osmolality overnight. Together with the documented desmopressin response, this was suggestive of a primary role for vasopressin in the pathogenesis of enuresis in the absence of bladder dysfunction. Recent studies no longer confirm this primary role of vasopressin. Other pathogenetic factors such as disordered renal sodium handling, hypercalciuria, increased prostaglandins and/or osmotic excretion might have a role. So far, little attention has been given to abnormalities in the circadian rhythm of glomerular filtration rate. We evaluated the circadian rhythm of glomerular filtration rate and diuresis in children with desmopressin resistant monosymptomatic nocturnal enuresis and nocturnal polyuria. We evaluated 15 children (9 boys) 9 to 14 years old with monosymptomatic nocturnal enuresis and nocturnal polyuria resistant to desmopressin treatment. The control group consisted of 25 children (12 boys) 9 to 16 years old with monosymptomatic nocturnal enuresis without nocturnal polyuria. Compared to the control population, children with nocturnal polyuria lost their circadian rhythm not only for diuresis and sodium excretion but also for glomerular filtration rate. Patients with monosymptomatic nocturnal enuresis and nocturnal polyuria lack a normal circadian rhythm for diuresis and sodium excretion, and the circadian rhythm of glomerular filtration rate is absent. This absence of circadian rhythm of glomerular filtration rate and/or sodium handling cannot be explained by a primary role of vasopressin, but rather by a disorder in circadian rhythm of renal glomerular and/or tubular functions.

Clinical dehydration and glomerular filtration rate in acute paediatric gastroenteritis.

PubMed

Milani, Gregorio P; Fossali, Emilio F; Perri, Alessandra; Vettori, Arianna; Grillo, Paolo; Agostoni, Carlo

2013-08-01

To evaluate changes in glomerular filtration rate in acute gastroenteritis. The correlation between two clinical diagnostic scales and glomerular filtration rate has been investigated in 113 children with acute gastroenteritis in a paediatric emergency setting. A significant reduction of GFR was found in 10% children less than, and 5% children higher than, 2 years of age with acute gastroenteritis. The differences observed as for risk of renal hypoperfusion suggests to consider the age of children as an important determinant to consider the dehydration status in acute gastroenteritis. ©2013 Foundation Acta Paediatrica. Published by John Wiley & Sons Ltd.

Filtration effects on ball bearing life and condition in a contaminated lubricant

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Moyer, D. W.

1978-01-01

Ball bearings were fatigue tested with a noncontaminated MIL-L-23699 lubricant and with a contaminated MIL-L-23699 lubricant under four levels of filtration. The test filters had absolute particle removal ratings of 3, 30, 49, and 105 microns. Aircraft turbine engine contaminants were injected into the filter's supply line at a constant rate of 125 milligrams per bearing hour. Bearing life and running track condition generally improved with finer filtration. The experimental lives of 3- and 30-micron filter bearings were statistically equivalent, approaching those obtained with the noncontaminated lubricant bearings. Compared to these bearings, the lives of the 49-micron bearings were statistically lower. The 105-micron bearings experienced gross wear. The degree of surface distress, weight loss, and probable failure mode were dependent on filtration level, with finer filtration being clearly beneficial.

Evaluation of systems for reducing the transmission of Porcine reproductive and respiratory syndrome virus by aerosol

PubMed Central

2006-01-01

Abstract The purpose of this study was to compare 3 methods for the reduction of aerosol transmission of Porcine reproductive and respiratory syndrome virus (PRRSV): high-efficiency particulate air (HEPA) filtration, low-cost filtration, and ultraviolet light (UV) irradiation. The HEPA-filtration system involved a pre-filter screen, a bag filter (EU8 rating), and a HEPA filter (EU13 rating). The low-cost-filtration system contained mosquito netting (pre-filter), a fiberglass furnace filter, and an electrostatic furnace filter. For UV irradiation, a lamp emitted UVC radiation at 253.7 nm. No form of intervention was used in the control group. The experimental facilities consisted of 2 chambers connected by a 1.3-m-long duct. Recipient pigs, housed in chamber 2, were exposed to artificial aerosols created by a mechanically operated mister containing modified live PRRSV vaccine located in chamber 1. Aerosol transmission of PRRSV occurred in 9 of the 10 control replicates, 8 of the 10 UVC-irradiation replicates, 4 of the 10 low-cost-filtration replicates, and 0 of the 10 HEPA-filtration replicates. When compared with no intervention, HEPA filtration and low-cost filtration significantly reduced PRRSV transmission (P < 0.0005 and = 0.0286, respectively), whereas UV irradiation had no effect (P = 0.5). However, low-cost filtration and UV irradiation were significantly less effective (P = 0.043 and P < 0.0005, respectively) than HEPA filtration. In conclusion, under the conditions of this study, HEPA filtration was significantly more effective at reducing aerosol transmission of PRRSV than the other methods evaluated. PMID:16548329

Demonstrated technology for high-rate filtration of oily wastes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Danzberger, A.H.; Nebolsine, R.

1980-01-01

A discussion covers the various techniques (gravity separation, air or gas flotation, and ultrafiltration) used to remove oil from wastewater; their relative advantages; the satisfactory performance of ultrahigh-rate (UHR) filters in various applications, including in a Standard Oil Co. (Ohio) refinery; the development of UHR filtration plants by Hydrotechnic Corp.; the design and advantages of Hydrotechnic's filters; filtration; flow control and head loss; the backwash process; and the capital, construction, and operating costs of UHR filters (1000 to 7000 cu m/hr).

The Effects of Antifoam Agent on Dead End Filtration Process

NASA Astrophysics Data System (ADS)

Mohamad Pauzi, S.; Ahmad, N.; Yahya, M. F.; Arifin, M. A.

2018-05-01

The formation of foam as a result from introducing gases during cell culture process in the bioprocess industry has indirectly affected the throughput of the product of interest. Due to that, antifoams were developed and established as one of the means to minimize the formation of foam in the cell culture. There are many types of antifoams but the silicone-type of antifoams are widely used in the bioprocess industry. Although the establishment of antifoam has aided the cell culture process, the impacts of its presence in the cell culture to the downstream process especially the dead end filtration is not widely discussed. The findings in the study emphasized on the dead end filtration performance that includes flux rate profile and the resulted filtration capacity. In this study, the concentrations of antifoam injected into the solution were varied from 0.2% v/v – 1.0% v/v and the solutions were filtered using constant flow method. The resulted maximum pressure readings and final flux rates indicated that the resistance exerted to the feed flow rate increased as the concentration of antifoam loaded in the solution increased. This later has led to the decline in the flux rates with percentage reduction between 32 – 68%. The calculated filter capacity for flux rate of 1000LMH ranged from 53 – 63L/m2 while it is in the range of 40 – 43L/m2 for flux rate of 2000LMH. The presence of antifoam agents in the feed load was determined to have negative effects on the dead end filtration performance and it may reduce the efficiency of the dead end filtration process.

Glomerular filtration rate and kidney size in type 2 (non-insulin-dependent) diabetes mellitus.

PubMed

Wirta, O R; Pasternack, A I

1995-07-01

The objective of the present study was to estimate glomerular filtration rate and kidney size in recently diagnosed and long-term type 2 (non-insulin-dependent) diabetic subjects. The study design comprised of a population-based controlled cross-sectional survey of middle-aged type 2 diabetic subjects in the City of Tampere, Southwest Finland. One hundred and fifty consecutive recently diagnosed and 146 long-term middle-aged type 2 diabetic subjects with a disease duration of at least five years and one hundred and fifty age- and sex-matched (to recent diabetic subjects) non-diabetic control subjects were recruited. The glomerular filtration rate by single-shot 51Cr-EDTA clearance and kidney size by native X-ray tomography were measured. The glomerular filtration rate (ml/min/1.73 m2) was increased in both recently diagnosed (males 121 [27] and females 112 [27]) and long-term (males 123 [24] and females 102 [36]) diabetic subjects (corrected for age) compared to control subjects (males 111 [26] and females 93 [17]). The kidney areas (cm2) were greater in both recent diabetic (males 116.6 [15.4] and females 99.1 [15.3] and long-term diabetic (males 118.3 [15.8] and females 100.4 [15.2]) subjects than in the control group (males 104.3 [12.0] and females 88.6 [12.0]). All differences between diabetic subjects and non-diabetic subjects were statistically significant (p < 0.05), except that between long-term diabetic and non-diabetic females for glomerular filtration rate (p = 0.07). Analyzed by linear regression glomerular filtration rate was related to kidney area in all study groups and to hemoglobin A1c in long-term diabetic males.(ABSTRACT TRUNCATED AT 250 WORDS)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azhar, A.; Hamdy, M.K.

Use of ultrafiltration membrane systems in stirred cell and in thin-channel systems for immobilizing enzyme (sweet potato intrinsic and crystalline beta-amylase) in hydrolysis of sweet potato through a continuous operation mode were studied. Both the filtration rate and reducing sugars, produced as the result of enzymic hydrolysis, decreased with the filtration time. The immobilized enzymes in the thin-channel system showed a much better performance compared to that in the stirred cell system. Addition of crystalline sweet potato beta-amylase to the sweet potato increased both the filtration rate and reducing-sugars content. Alcohol fermentation of the filtrate resulted in an alcohol contentmore » of 4.2%. This represented fermentation of 95% of the sugars with an efficiency of 88%.« less

Application of a new dynamic transport model to predict the evolution of performances throughout the nanofiltration of single salt solutions in concentration and diafiltration modes.

PubMed

Déon, Sébastien; Lam, Boukary; Fievet, Patrick

2018-06-01

Although many knowledge models describing the rejection of ionic compounds by nanofiltration membranes are available in literature, they are all used in full recycling mode. Indeed, both permeate and retentate streams are recycled in order to maintain constant concentrations in the feed solution. However, nanofiltration of real effluents is implemented either in concentration or diafiltration modes, for which the permeate stream is collected. In these conditions, concentrations progressively evolve during filtration and classical models fail to predict performances. In this paper, an improvement of the so called "Donnan Steric Pore Model", which includes both volume and concentration variations over time is proposed. This dynamic model is used here to predict the evolution of volumes and concentrations in both permeate and retentate streams during the filtration of salt solutions. This model was found to predict accurately the filtration performances with various salts whether the filtration is performed in concentration or diafiltration modes. The parameters of the usual model can be easily assessed from full batch experiments before being used in the dynamic version. Nevertheless, it is also highlighted that the variation of the membrane charge due to the evolution of feed concentration over time has to be taken into account in the model through the use of adsorption isotherms. Copyright © 2018 Elsevier Ltd. All rights reserved.

Prediction of the filtrate particle size distribution from the pore size distribution in membrane filtration: Numerical correlations from computer simulations

NASA Astrophysics Data System (ADS)

Marrufo-Hernández, Norma Alejandra; Hernández-Guerrero, Maribel; Nápoles-Duarte, José Manuel; Palomares-Báez, Juan Pedro; Chávez-Rojo, Marco Antonio

2018-03-01

We present a computational model that describes the diffusion of a hard spheres colloidal fluid through a membrane. The membrane matrix is modeled as a series of flat parallel planes with circular pores of different sizes and random spatial distribution. This model was employed to determine how the size distribution of the colloidal filtrate depends on the size distributions of both, the particles in the feed and the pores of the membrane, as well as to describe the filtration kinetics. A Brownian dynamics simulation study considering normal distributions was developed in order to determine empirical correlations between the parameters that characterize these distributions. The model can also be extended to other distributions such as log-normal. This study could, therefore, facilitate the selection of membranes for industrial or scientific filtration processes once the size distribution of the feed is known and the expected characteristics in the filtrate have been defined.

Transport of Cryptosporidium oocysts in porous media: Role of straining and physicochemical filtration

USGS Publications Warehouse

Tufenkji, N.; Miller, G.F.; Ryan, J.N.; Harvey, R.W.; Elimelech, M.

2004-01-01

The transport and filtration behavior of Cryptosporidium parvum oocysts in columns packed with quartz sand was systematically examined under repulsive electrostatic conditions. An increase in solution ionic strength resulted in greater oocyst deposition rates despite theoretical predictions of a significant electrostatic energy barrier to deposition. Relatively high deposition rates obtained with both oocysts and polystyrene latex particles of comparable size at low ionic strength (1 mM) suggest that a physical mechanism may play a key role in oocyst removal. Supporting experiments conducted with latex particles of varying sizes, under very low ionic strength conditions where physicochemical filtration is negligible, clearly indicated that physical straining is an important capture mechanism. The results of this study indicate that irregularity of sand grain shape (verified by SEM imaging) contributes considerably to the straining potential of the porous medium. Hence, both straining and physicochemical filtration are expected to control the removal of C. parvum oocysts in settings typical of riverbank filtration, soil infiltration, and slow sand filtration. Because classic colloid filtration theory does not account for removal by straining, these observations have important implications with respect to predictions of oocyst transport.

Effects of dilute-acid pretreatment conditions on filtration performance of corn stover hydrolyzate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sievers, David A.; Kuhn, Erik M.; Tucker, Melvin P.

In this study, the reaction conditions used during dilute-acid pretreatment of lignocellulosic biomass control the carbohydrate digestion yield and also hydrolyzate properties. Depending on the conversion route of interest, solid-liquid separation (SLS) may be required to split the hemicellulose-rich liquor from the cellulose-rich insoluble solids, and slurry properties are important for SLS. Corn stover was pretreated at different reaction conditions and the slurries were assessed for conversion yield and filtration performance. Increasing pretreatment temperature reduced the solids mean particle size and resulted in slower slurry filtration rates when vacuum filtered or pressure filtered. Corn stover pretreated at 165 °C formore » 10 min and with 1% H 2SO 4 exhibited the highest xylose yield and best filtration performance with a no-wash filtration rate of 80 kg/h m 2 and cake permeability of 15 x 10 -15.« less

Effects of dilute-acid pretreatment conditions on filtration performance of corn stover hydrolyzate

DOE PAGES

Sievers, David A.; Kuhn, Erik M.; Tucker, Melvin P.; ...

2017-06-28

In this study, the reaction conditions used during dilute-acid pretreatment of lignocellulosic biomass control the carbohydrate digestion yield and also hydrolyzate properties. Depending on the conversion route of interest, solid-liquid separation (SLS) may be required to split the hemicellulose-rich liquor from the cellulose-rich insoluble solids, and slurry properties are important for SLS. Corn stover was pretreated at different reaction conditions and the slurries were assessed for conversion yield and filtration performance. Increasing pretreatment temperature reduced the solids mean particle size and resulted in slower slurry filtration rates when vacuum filtered or pressure filtered. Corn stover pretreated at 165 °C formore » 10 min and with 1% H 2SO 4 exhibited the highest xylose yield and best filtration performance with a no-wash filtration rate of 80 kg/h m 2 and cake permeability of 15 x 10 -15.« less

Magnetic Resonance Imaging-Derived Renal Oxygenation and Perfusion During Continuous, Steady-State Angiotensin-II Infusion in Healthy Humans.

PubMed

van der Bel, René; Coolen, Bram F; Nederveen, Aart J; Potters, Wouter V; Verberne, Hein J; Vogt, Liffert; Stroes, Erik S G; Krediet, C T Paul

2016-03-28

The role of kidney hypoxia is considered pivotal in the progression of chronic kidney disease. A widely used method to assess kidney oxygenation is blood oxygen level dependent (BOLD)-magnetic resonance imaging (MRI), but its interpretation remains problematic. The BOLD-MRI signal is the result of kidney oxygen consumption (a proxy of glomerular filtration) and supply (ie, glomerular perfusion). Therefore, we hypothesized that with pharmacological modulation of kidney blood flow, renal oxygenation, as assessed by BOLD-MRI, correlates to filtration fraction (ie, glomerular filtration rate/effective renal plasma flow) in healthy humans. Eight healthy volunteers were subjected to continuous angiotensin-II infusion at 0.3, 0.9, and 3.0 ng/kg per minute. At each dose, renal oxygenation and blood flow were assessed using BOLD and phase-contrast MRI. Subsequently, "gold standard" glomerular filtration rate/effective renal plasma flow measurements were performed under the same conditions. Renal plasma flow decreased dose dependently from 660±146 to 467±103 mL/min per 1.73 m(2) (F[3, 21]=33.3, P<0.001). Glomerular filtration rate decreased from 121±23 to 110±18 mL/min per 1.73 m(2) (F[1.8, 2.4]=6.4, P=0.013). Cortical transverse relaxation rate (R2*; increases in R2* represent decreases in oxygenation) increased by 7.2±3.8% (F[3, 21]=7.37, P=0.001); medullar R2* did not change. Cortical R2* related to filtration fraction (R(2) 0.46, P<0.001). By direct comparison between "gold standard" kidney function measurements and BOLD MRI, we showed that cortical oxygenation measured by BOLD MRI relates poorly to glomerular filtration rate but is associated with filtration fraction. For future studies, there may be a need to include renal plasma flow measurements when employing renal BOLD-MRI. © 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Bioavailability and Methylation Potential of Mercury Sulfides in Sediments

DTIC Science & Technology

2014-08-01

such as size separation (i.e. filtration with a particular pore size or molecular weight cutoff) or metal-ligand complexation from experimentally ...and 6 nM HgS microparticles. The error bars represent ±1 s.d. for duplicate samples. Results of Hg fractionation by filtration and (ultra... results from filtration (Figures S2). These differences in the data indicated that the nHgS dissolution rate could be overestimated by the filtration data

Experimental investigation of the formaldehyde removal mechanisms in a dynamic botanical filtration system for indoor air purification.

PubMed

Wang, Zhiqiang; Pei, Jingjing; Zhang, Jensen S

2014-09-15

Botanical filtration has been proved to be effective for indoor gas pollutant removal. To understand the roles of different transport, storage and removal mechanism by a dynamic botanical air filter, a series of experimental investigations were designed and conducted in this paper. Golden Pothos (Epipremnum aureum) plants was selected for test, and its original soil or activated/pebbles root bed was used in different test cases. It was found that flowing air through the root bed with microbes dynamically was essential to obtain meaningful formaldehyde removal efficiency. For static potted plant as normally place in rooms, the clean air delivery rate (CADR), which is often used to quantify the air cleaning ability of portable air cleaners, was only ∼ 5.1m(3)/h per m(2) bed, while when dynamically with air flow through the bed, the CADR increased to ∼ 233 m(3)/h per m(2) bed. The calculated CADR due to microbial activity is ∼ 108 m(3)/h per m(2) bed. Moisture in the root bed also played an important role, both for maintaining a favorable living condition for microbes and for absorbing water-soluble compounds such as formaldehyde. The role of the plant was to introduce and maintain a favorable microbe community which effectively degraded the volatile organic compounds adsorbed or absorbed by the root bed. The presence of the plant increased the removal efficiency by a factor of two based on the results from the bench-scale root bed experiments. Copyright © 2014 Elsevier B.V. All rights reserved.

Study of the filtration performance of a plain wave fabric filter using response surface methodology.

PubMed

Qian, Fuping; Wang, Haigang

2010-04-15

The gas-solid two-phase flows in the plain wave fabric filter were simulated by computational fluid dynamics (CFD) technology, and the warps and wefts of the fabric filter were made of filaments with different dimensions. The numerical solutions were carried out using commercial computational fluid dynamics (CFD) code Fluent 6.1. The filtration performances of the plain wave fabric filter with different geometry parameters and operating condition, including the horizontal distance, the vertical distance and the face velocity were calculated. The effects of geometry parameters and operating condition on filtration efficiency and pressure drop were studied using response surface methodology (RSM) by means of the statistical software (Minitab V14), and two second-order polynomial models were obtained with regard to the effect of the three factors as stated above. Moreover, the models were modified by dismissing the insignificant terms. The results show that the horizontal distance, vertical distance and the face velocity all play an important role in influencing the filtration efficiency and pressure drop of the plane wave fabric filters. The horizontal distance of 3.8 times the fiber diameter, the vertical distance of 4.0 times the fiber diameter and Reynolds number of 0.98 are found to be the optimal conditions to achieve the highest filtration efficiency at the same face velocity, while maintaining an acceptable pressure drop. 2009 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Azhar, A.; Hamdy, M.K.

Use of ultrafiltration membrane systems in stirred cell and in thin-channel systems for immobilizing enzyme (sweet potato intrinsic and crystalline /beta/-amylase) in hydrolysis of sweet potato through a continuous operation mode were studied. Both the filtration rate and reducing sugars, produced as the result of enzymatic hydrolysis, decreased with the filtration time. THe immobilized enzymes in the thin-channel system showed a much better performance compared to that in the stirred cell system. Addition of crystalline sweet potato /beta/-amylase to the sweet potato increased both the filtration rate and reducing-sugars content. Alcoholic fermentation of the filtrate resulted in an alcohol contentmore » of 4.2%. This represented fermentation of 95% of the sugars with an efficiency of 88%. 17 refs.« less

Evaluation of Hollow-Fiber Ultrafiltration Primary Concentration of Pathogens and Secondary Concentration of Viruses from Water

EPA Science Inventory

In this study, tangential hollow-fiber ultrafiltration (HFUF) was evaluated for virus and Cryptosporidium parvum concentration. Recovery of viruses at a low filtration rate was found to be significantly greater than at a higher filtration rate, with the recoveries of bacteriopha...

Effect of filtration on rolling-element-bearing life in contaminated lubricant environment

NASA Technical Reports Server (NTRS)

Loewenthal, S. H.; Moyer, D. W.; Sherlock, J. J.

1978-01-01

Fatigue tests were conducted on groups of 65 millimeter-bore ball bearings under four levels of filtration with and without a contaminated MIL-L-23699 lubricant. The baseline series used noncontaminated oil with 49 micron absolute filtration. In the remaining tests contaminants of the composition found in aircraft engine filters were injected into the filter's supply line at a constant rate of 125 milligrams per bearing-hour. The test filters had absolute particle removal ratings of 3, 30, 49, and 105 microns (0.45, 10, 30, and 70 microns nominal), respectively. Bearings were tested at 15,000 rpm under 4580 newtons radial load. Bearing life and running tract condition generally improved with finer filtration. The 3 and 30 micron filter bearings in a contaminated lubricant had statistically equivalent lives, approaching those from the baseline tests. The experimental lives of 49 micron bearings were approximately half the baseline bearing's lives. Bearings tested with the 105 micron filter experienced wear failures. The degree of surface distress, weight loss, and probable failure mode were found to be dependent on filtration level, with finer filtration being clearly beneficial.

Comparison of interleukin-6 removal properties among hemofilters consisting of varying membrane materials and surface areas: an in vitro study.

PubMed

Hirayama, Yo; Oda, Shigeto; Wakabayashi, Kiyohito; Sadahiro, Tomohito; Nakamura, Masataka; Watanabe, Eizo; Tateishi, Yoshihisa

2011-01-01

We sought to identify the most relevant hemofilter for cytokine removal based on the mechanisms of filtration and adsorption. Ascites were filtered using four types of hemofilters composed of different membrane materials (polymethyl methacrylate, PMMA, cellulose triacetate, CTA, or polysulfone, PS) and different surface areas (1.0 or 2.1 m(2)) to investigate the rate of interleukin-6 (IL-6) filtration. Next, ascites were perfused through each hemofilter without obtaining a filtrate to study each filter's adsorptive capability. The PMMA hemofilters resulted in a marginal observed IL-6 filtration rates, whereas the CTA and PS hemofilters resulted in highly effective IL-6 filtration. Regarding the IL-6 adsorptive capabilities of the filters, the PMMA hemofilter with a large surface area showed the highest level of IL-6 clearance. The present findings suggest that when cytokine removal based on filtration is desired, CTA or PS hemofilters should be selected. When IL-6 removal based on adsorption is desired, a PMMA hemofilter with a large surface area should be selected. Copyright © 2010 S. Karger AG, Basel.

Air filtration in the free molecular flow regime: a review of high-efficiency particulate air filters based on carbon nanotubes.

PubMed

Li, Peng; Wang, Chunya; Zhang, Yingying; Wei, Fei

2014-11-01

Air filtration in the free molecular flow (FMF) regime is important and challenging because a higher filtration efficiency and lower pressure drop are obtained when the fiber diameter is smaller than the gas mean free path in the FMF regime. In previous studies, FMF conditions have been obtained by increasing the gas mean free path through reducing the pressure and increasing the temperature. In the case of carbon nanotubes (CNTs) with nanoscale diameters, it is possible to filtrate in the FMF regime under normal conditions. This paper reviews recent progress in theoretical and experimental studies of air filtration in the FMF regime. Typical structure models of high-efficiency particulate (HEPA) air filters based on CNTs are introduced. The pressure drop in air filters operated in the FMF regime is less than that predicted by the conventional air filtration theory. The thinnest HEPA filters fabricated from single-walled CNT films have an extremely low pressure drop. CNT air filters with a gradient nanostructure are shown to give a much better filtration performance in dynamic filtration. CNT air filters with a hierarchical structure and an agglomerated CNT fluidized bed air filter are also introduced. Finally, the challenges and opportunities for the application of CNTs in air filtration are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herman, D.

The Savannah River Site (SRS) Actinide Removal Process has been processing salt waste since 2008. This process includes a filtration step in the 512-S facility. Initial operations included the addition, or strike, of monosodium titanate (MST) to remove soluble actinides and strontium. The added MST and any entrained sludge solids were then separated from the supernate by cross flow filtration. During this time, the filter operations have, on many occasions, been the bottleneck process limiting the rate of salt processing. Recently, 512-S- has started operations utilizing “No-MST” where the MST actinide removal strike was not performed and the supernate wasmore » simply pre-filtered prior to Cs removal processing. Direct filtration of decanted tank supernate, as demonstrated in 512-S, is the proposed method of operation for the Hanford Low Activity Waste Pretreatment System (LAWPS) facility. Processing decanted supernate without MST solids has been demonstrated for cross flow filtration to provide a significant improvement in production with the SRS Salt Batches 8 and 9 feed chemistries. The average filtration rate for the first 512-S batch processing cycle using No-MST has increased filtrate production by over 35% of the historical average. The increase was sustained for more than double the amount of filtrate batches processed before cleaning of the filter was necessary. While there are differences in the design of the 512-S and Hanford filter systems, the 512-S system should provide a reasonable indication of LAWPS filter performance with similar feed properties. Based on the data from the 512-S facility and with favorable feed properties, the LAWPS filter, as currently sized at over twice the size of the 512-S filter (532 square feet filtration area versus 235 square feet), has the potential to provide sustained filtrate production at the upper range of the planned LAWPS production rate of 17 gpm.« less

Using the developed cross-flow filtration chip for collecting blood plasma under high flow rate condition and applying the immunoglobulin E detection

NASA Astrophysics Data System (ADS)

Yeh, Chia-Hsien; Hung, Chia-Wei; Wu, Chun-Han; Lin, Yu-Cheng

2014-09-01

This paper presents a cross-flow filtration chip for separating blood cells (white blood cells, red blood cells, and platelets) and obtaining blood plasma from human blood. Our strategy is to flow the sample solution in parallel to the membrane, which can generate a parallel shear stress to remove the clogging microparticles on the membrane, so the pure sample solution is obtained in the reservoir. The cross-flow filtration chip includes a cross-flow layer, a Ni-Pd alloy micro-porous membrane, and a reservoir layer. The three layers are packaged in a polymethylmethacrylate (PMMA) frame to create the cross-flow filtration chip. Various dilutions of the blood sample (original, 2 × , 3 × , 5 × , and 10×), pore sizes with different diameters (1 µm, 2 µm, 4 µm, 7 µm, and 10 µm), and different flow rates (1 mL/min, 3 mL/min, 5 mL/min, 7 mL/min, and 10 mL/min) are tested to determine their effects on filtration percentage. The best filtration percentage is 96.2% when the dilution of the blood sample is 10 × , the diameter of pore size of a Ni-Pd alloy micro-porous membrane is 2 µm, and the flow rate is 10 mL/min. Finally, for the clinical tests of the immunoglobulin E (IgE) concentration, the cross-flow filtration chip is used to filter the blood of the allergy patients to obtain the blood plasma. This filtered blood plasma is compared with that obtained using the conventional centrifugation based on the enzyme-linked immunosorbent assay. The results reveal that these two blood separation methods have similar detection trends. The proposed filtration chip has the advantages of low cost, short filtration time, and easy operation and thus can be applied to the separation of microparticles, cells, bacteria, and blood.

Effects of levosimendan on glomerular filtration rate, renal blood flow, and renal oxygenation after cardiac surgery with cardiopulmonary bypass: a randomized placebo-controlled study.

PubMed

Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2013-10-01

Acute kidney injury develops in a large proportion of patients after cardiac surgery because of the low cardiac output syndrome. The inodilator levosimendan increases cardiac output after cardiac surgery with cardiopulmonary bypass, but a detailed analysis of its effects on renal perfusion, glomerular filtration, and renal oxygenation in this group of patients is lacking. We therefore evaluated the effects of levosimendan on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen demand/supply relationship, i.e., renal oxygen extraction, early after cardiac surgery with cardiopulmonary bypass. Prospective, placebo-controlled, and randomized trial. Cardiothoracic ICU of a tertiary center. Postcardiac surgery patients (n=30). The patients were randomized to receive levosimendan, 0.1 µg/kg/min after a loading dose of 12 µg/kg (n=15), or placebo (n=15). The experimental procedure started 4-6 hours after surgery in the ICU during propofol sedation and mechanical ventilation. Systemic hemodynamic were evaluated by a pulmonary artery thermodilution catheter. Renal blood flow and glomerular filtration rate were measured by the renal vein retrograde thermodilution technique and by renal extraction of Cr-EDTA, respectively. Central venous pressure was kept constant by colloid/crystalloid infusion. Compared to placebo, levosimendan increased cardiac index (22%), stroke volume index (15%), and heart rate (7%) and decreased systemic vascular resistance index (21%), whereas mean arterial pressure was not affected. Levosimendan induced significant increases in renal blood flow (12%, p<0.05) and glomerular filtration rate (21%, p<0.05), decreased renal vascular resistance (18%, p<0.05) but caused no significant changes in filtration fraction, renal oxygen consumption, or renal oxygen extraction, compared to placebo. After cardiac surgery with cardiopulmonary bypass, levosimendan induces a vasodilation, preferentially of preglomerular resistance vessels, increasing both renal blood flow and glomerular filtration rate without jeopardizing renal oxygenation. Due to its pharmacodynamic profile, levosimendan might be an interesting alternative for treatment of postoperative heart failure complicated by acute kidney injury in postcardiac surgery patients.

Computational fluid dynamics simulations of membrane filtration process adapted for water treatment of aerated sewage lagoons.

PubMed

Cano, Grégory; Mouahid, Adil; Carretier, Emilie; Guasp, Pascal; Dhaler, Didier; Castelas, Bernard; Moulin, Philippe

2015-01-01

The aim of this study is to apply the membrane bioreactor technology in an oxidation ditch in submerged conditions. This new wastewater filtration process will benefit rural areas (<5,000 population equivalent) subject to chronic water shortages by reusing this water for irrigation of green areas. For this purpose, the membranes developed without support are immersed in an aeration well and work in suction mode. The development of the membrane without support and more precisely the performance of spacers are approached by computational fluid dynamics in order to provide the best compromise between pressure drop/flow velocity and permeate flux. The numerical results on the layout and the membrane modules' geometry in the aeration well indicate that the optimal configuration is to install the membranes horizontally on three levels. Membranes should be connected to each other to a manifold providing a total membrane area of 18 m². Loss rate compared to the theoretical throughput is relatively low (less than 3%). Preliminary data obtained by modeling the lagoon provide access to its hydrodynamics, revealing that recirculation zones can be optimized by making changes in the operating conditions. The experimental validation of these results and taking into account the aeration in the numerical models are underway.

Calibration of Kodak EDR2 film for patient skin dose assessment in cardiac catheterization procedures.

PubMed

Morrell, Rachel E; Rogers, Andy

2004-12-21

Kodak EDR2 film has been calibrated across the range of exposure conditions encountered in our cardiac catheterization laboratory. Its dose-response function has been successfully modelled, up to the saturation point of 1 Gy. The most important factor affecting film sensitivity is the use of beam filtration. Spectral filtration and kVp together account for a variation in dose per optical density of -10% to +25%, at 160 mGy. The use of a dynamic wedge filter may cause doses to be underestimated by up to 6%. The film is relatively insensitive to variations in batch, field size, exposure rate, time to processing and day-to-day fluctuations in processor performance. Overall uncertainty in the calibration is estimated to be -20% to +40%, at 160 mGy. However, the uncertainty increases at higher doses, as the curve saturates. Artefacts were seen on a number of films, due to faults in the light-proofing of the film packets.

Removals of cryptosporidium parvum oocysts and cryptosporidium-sized polystyrene microspheres from swimming pool water by diatomaceous earth filtration and perlite-sand filtration.

PubMed

Lu, Ping; Amburgey, James E; Hill, Vincent R; Murphy, Jennifer L; Schneeberger, Chandra L; Arrowood, Michael J; Yuan, Tao

2017-06-01

Removal of Cryptosporidium-sized microspheres and Cryptosporidium parvum oocysts from swimming pools was investigated using diatomaceous earth (DE) precoat filtration and perlite-sand filtration. In pilot-scale experiments, microsphere removals of up to 2 log were obtained with 0.7 kg·DE/m 2 at a filtration rate of 5 m/h. A slightly higher microsphere removal (2.3 log) was obtained for these DE-precoated filters when the filtration rate was 3.6 m/h. Additionally, pilot-scale perlite-sand filters achieved greater than 2 log removal when at least 0.37 kg/m 2 of perlite was used compared to 0.1-0.4 log removal without perlite both at a surface loading rate of 37 m/h. Full-scale testing achieved 2.7 log of microspheres and oocysts removal when 0.7 kg·DE/m 2 was used at 3.6 m/h. Removals were significantly decreased by a 15-minute interruption of the flow (without any mechanical agitation) to the DE filter in pilot-scale studies, which was not observed in full-scale filters. Microsphere removals were 2.7 log by perlite-sand filtration in a full-scale swimming pool filter operated at 34 m/h with 0.5 kg/m 2 of perlite. The results demonstrate that either a DE precoat filter or a perlite-sand filter can improve the efficiency of removal of microspheres and oocysts from swimming pools over a standard sand filter under the conditions studied.

Nomograms for predicting graft function and survival in living donor kidney transplantation based on the UNOS Registry.

PubMed

Tiong, H Y; Goldfarb, D A; Kattan, M W; Alster, J M; Thuita, L; Yu, C; Wee, A; Poggio, E D

2009-03-01

We developed nomograms that predict transplant renal function at 1 year (Modification of Diet in Renal Disease equation [estimated glomerular filtration rate]) and 5-year graft survival after living donor kidney transplantation. Data for living donor renal transplants were obtained from the United Network for Organ Sharing registry for 2000 to 2003. Nomograms were designed using linear or Cox regression models to predict 1-year estimated glomerular filtration rate and 5-year graft survival based on pretransplant information including demographic factors, immunosuppressive therapy, immunological factors and organ procurement technique. A third nomogram was constructed to predict 5-year graft survival using additional information available by 6 months after transplantation. These data included delayed graft function, any treated rejection episodes and the 6-month estimated glomerular filtration rate. The nomograms were internally validated using 10-fold cross-validation. The renal function nomogram had an r-square value of 0.13. It worked best when predicting estimated glomerular filtration rate values between 50 and 70 ml per minute per 1.73 m(2). The 5-year graft survival nomograms had a concordance index of 0.71 for the pretransplant nomogram and 0.78 for the 6-month posttransplant nomogram. Calibration was adequate for all nomograms. Nomograms based on data from the United Network for Organ Sharing registry have been validated to predict the 1-year estimated glomerular filtration rate and 5-year graft survival. These nomograms may facilitate individualized patient care in living donor kidney transplantation.

Long-Term Renal Function Recovery following Radical Nephrectomy for Kidney Cancer: Results from a Multicenter Confirmatory Study.

PubMed

Zabor, Emily C; Furberg, Helena; Lee, Byron; Campbell, Steven; Lane, Brian R; Thompson, R Houston; Antonio, Elvis Caraballo; Noyes, Sabrina L; Zaid, Harras; Jaimes, Edgar A; Russo, Paul

2018-04-01

We sought to confirm the findings from a previous single institution study of 572 patients from Memorial Sloan Kettering Cancer Center in which we found that 49% of patients recovered to the preoperative estimated glomerular filtration rate within 2 years following radical nephrectomy for renal cell carcinoma. A multicenter retrospective study was performed in 1,928 patients using data contributed from 3 independent centers. The outcome of interest was postoperative recovery to the preoperative estimated glomerular filtration rate. Data were analyzed using cumulative incidence and competing risks regression with death from any cause treated as a competing event. This study demonstrated that 45% of patients had recovered to the preoperative estimated glomerular filtration rate by 2 years following radical nephrectomy. Furthermore, this study confirmed that recovery of renal function differed according to preoperative renal function such that patients with a lower preoperative estimated glomerular filtration rate had an increased chance of recovery. This study also suggested that larger tumor size and female gender were significantly associated with an increased chance of renal function recovery. In this multicenter retrospective study we confirmed that in the long term a large proportion of patients recover to preoperative renal function following radical nephrectomy for kidney tumors. Recovery is more likely among those with a lower preoperative estimated glomerular filtration rate. Copyright © 2018 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Contribution of stone size to chronic kidney disease in kidney stone formers.

PubMed

Ahmadi, Farrokhlagha; Etemadi, Samira Motedayen; Lessan-Pezeshki, Mahbob; Mahdavi-Mazdeh, Mitra; Ayati, Mohsen; Mir, Alireza; Yazdi, Hadi Rokni

2015-01-01

To determine whether stone burden correlates with the degree of chronic kidney disease in kidney stone formers. A total of 97 extracorporeal shockwave lithotripsy candidates aged 18 years and older were included. Size, number and location of the kidney stones, along with cumulative stone size, defined as the sum of diameters of all stones) were determined. Estimated glomerular filtration rate was determined using the Chronic Kidney Disease Epidemiology Collaboration cystatin C/creatinine equation, and chronic kidney disease was defined as estimated glomerular filtration rate <60 mL/min/1.73 m(2). In individuals with cumulative stone size <20 mm, estimated glomerular filtration rate significantly decreased when moving from the first (estimated glomerular filtration rate 75.5 ± 17.8 mL/min/1.73 m(2)) to the fourth (estimated glomerular filtration rate 56.4 ± 20.44 mL/min/1.73 m(2) ) quartile (P = 0.004). When patients with a cumulative stone size ≥ 20 mm were included, the observed association was rendered non-significant. In individuals with a cumulative stone size < 20 mm, each 1-mm increase in cumulative stone size was associated with a 20% increased risk of having chronic kidney disease. The relationship persisted even after adjustment for age, sex, body mass index, C-reactive protein, fasting plasma glucose, thyroid stimulating hormone, presence of microalbuminuria, history of renal calculi, history of extracorporeal shockwave lithotripsy, number and location of the stones (odds ratio 1.24, 95% confidence interval 1.02-1.52). The same was not observed for individuals with a cumulative stone size ≥ 20 mm. In kidney stone formers with a cumulative stone size up to 20 mm, estimated glomerular filtration rate linearly declines with increasing cumulative stone size. Additionally, cumulative stone size is an independent predictor of chronic kidney disease in this group of patients. © 2014 The Japanese Urological Association.

Clinical Relevance of Differences in Glomerular Filtration Rate Estimations in Frail Older People by Creatinine- vs. Cystatin C-Based Formulae.

PubMed

Jacobs, Anne; Benraad, Carolien; Wetzels, Jack; Rikkert, Marcel Olde; Kramers, Cornelis

2017-06-01

The risk of incorrect medication dosing is high in frail older people. Therefore, accurate assessment of the glomerular filtration rate is important. The objective of this study was to compare the estimated glomerular filtration rate using creatinine- and cystatin C-based formulae, the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, in frail older people. We hypothesized that frailty determines the difference between the creatinine- and cystatin C-based formulae. The mean difference between CKD-EPI creatinine and cystatin C was determined using (cross-sectional) data of 55 patients (mean age 73 years) admitted to a psychiatric ward for older adults. The level of agreement of these estimations was assessed by a Bland-Altman analysis. In all patients, the Rockwood's Frailty Index was derived and correlated with the mean difference between CKD-EPI creatinine and cystatin C. The mean difference between CKD-EPI creatinine (mean 71.2 mL/min/1.73 m 2 ) and CKD-EPI cystatin C (mean 57.6 mL/min/1.73 m 2 ) was 13.6 mL/min/1.73 m 2 (p < 0.0001). The two standard deviation limit in the Bland-Altman plot was large (43.2 mL/min/1.73 m 2 ), which represents a low level of agreement. The Frailty Index did not correlate with the mean difference between the creatinine- and cystatin C-based glomerular filtration rate (Pearson correlation coefficient 0.182, p = 0.184). There was a significant gap between a creatinine- and cystatin C-based estimation of glomerular filtration rate, irrespective of frailty. The range of differences between the commonly used estimated glomerular filtration rate formulae might result in clinically relevant differences in drug prescription and differences in chronic kidney disease staging.

Investigations into the fouling mechanism of parvovirus filters during filtration of freeze-thawed mAb drug substance solutions.

PubMed

Barnard, James G; Kahn, David; Cetlin, David; Randolph, Theodore W; Carpenter, John F

2014-03-01

Filtration to remove viruses is one of the single most expensive steps in the production of mAb drug products. Therefore, virus filtration steps should be fully optimized, and any decline in flow rates warrants investigation into the causes of such membrane fouling. In the current study, it was found that freezing and thawing of a mAb bulk drug solution caused a substantial decrease in viral filter membrane flow rate. Freezing and thawing also caused formation of aggregates and particles across a broad size range, including particles that could be detected by microflow imaging (≥1 μm in size). However, removal of these particles offered little protection against flow rate decline during viral filtration. Further investigation revealed that trace amounts of aggregates (ca. 10⁻⁶ of the total mass of protein in solution) approximately 20-40 nm in size were primarily responsible for the observed membrane fouling. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Investigation of the influence of the zeta-potential on the filtration rate in the presence of collectors

NASA Technical Reports Server (NTRS)

Provirnina, E. V.; Barbin, M. B.

1984-01-01

The value of the zeta-potential does not have an explicit effect, which is expressed by a simple math correlation, on filtration rate when a solution of the tested collector is filtered through a cake prepared under standard conditions from the examined particulate material. The zeta-potential measurements and filtration tests were carried out on silica and galena with solutions contg. a cationic container ANP and Et xanthane, resp. at PH = 6.5, varying concentration of the agent (0-2500 g/ton), and under a vacuum of 100 to 600 mm Hg.

Pharmacologic Atrial Natriuretic Peptide Reduces Human Leg Capillary Filtration

NASA Technical Reports Server (NTRS)

Watenpaugh, Donald E.; Vissing, Susanne F.; Lane, Lynda D.; Buckey, Jay C.; Firth, Brian G.; Erdman, William; Hargens, Alan R.; Blomqvist, C. Gunnar

1995-01-01

Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethysmography of supine healthy male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n = 6) and during placebo infusion (n = 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma (ANP) from 30 +/- 4 to 2,568 +/- 595 pmol/L. Systemic hemoconcentration occurred during ANP infusion: mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3%, respectively, relative to preinfusion baseline values (p less than 0.05). Mean calf filtration, however, was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20% with ANP infusion, whereas blood pressure was unchanged. Calf conductance (blood flow/ arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, pharmacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchnic sites or both, while having the opposite effect in the leg.

Exploration Mission Particulate Matter Filtration Technology Performance Testing in a Simulated Spacecraft Cabin Ventilation System

NASA Technical Reports Server (NTRS)

Agui, Juan H.; Vijayakumar, R.; Perry, Jay L.; Frederick, Kenneth R.; Mccormick, Robert M.

2017-01-01

Human deep space exploration missions will require advances in long-life, low maintenance airborne particulate matter filtration technology. As one of the National Aeronautics and Space Administrations (NASA) developments in this area, a prototype of a new regenerable, multi-stage particulate matter filtration technology was tested in an International Space Station (ISS) module simulation facility. As previously reported, the key features of the filter system include inertial and media filtration with regeneration and in-place media replacement techniques. The testing facility can simulate aspects of the cabin environment aboard the ISS and contains flight-like cabin ventilation system components. The filtration technology test article was installed at the inlet of the central ventilation system duct and instrumented to provide performance data under nominal flow conditions. In-place regeneration operations were also evaluated. The real-time data included pressure drop across the filter stages, process air flow rate, ambient pressure, humidity and temperature. In addition, two video cameras positioned at the filtration technology test articles inlet and outlet were used to capture the mechanical performance of the filter media indexing operation under varying air flow rates. Recent test results are presented and future design recommendations are discussed.

Estimation of Glomerular Filtration Rate from Plasma Clearance of 51-Chromium Edetic Acid

PubMed Central

Chantler, C.; Barratt, T. M.

1972-01-01

The glomerular filtration rate was estimated by a single compartment analysis of the rate of fall of plasma concentration of 51-chromium edetic acid after a single intravenous injection. This slope clearance consistently overestimated the simultaneously determined standard urinary clearance, but could be used to predict the latter with an accuracy of ±9% (95% confidence limits). The coefficient of variation of replicate estimates of the slope clearance in the same individual was 3·9%; thus two estimates of glomerular filtration rate by this technique which differ by 11% have a 95% probability of reflecting a genuine difference. The method requires an intravenous injection and blood samples at 2 and 4 hours; urine samples are not required. It is simple, safe, and precise, and is applicable to children. PMID:4625784

Reducing bottom anti-reflective coating (BARC) defects: optimizing and decoupling the filtration and dispense process

NASA Astrophysics Data System (ADS)

Brakensiek, Nickolas L.; Martin, Gary; Simmons, Sean; Batchelder, Traci

2006-03-01

Semiconductor device manufacturing is one of the cleanest manufacturing operations that can be found in the world today. It has to be that way; a particle on a wafer today can kill an entire device, which raises the costs, and therefore reduces the profits, of the manufacturing company in two ways: it must produce extra wafers to make up for the lost die, and it has less product to sell. In today's state-of-the-art fab, everything is filtered to the lowest pore size available. This practice is fairly easy for gases because a gas molecule is very small compared to the pore size of the filter. Filtering liquids, especially photochemicals such as photoresists and BARCs, can be much harder because the molecules that form the polymers used to manufacture the photochemicals are approaching the filter pore size. As a result, filters may plug up, filtration rates may drop, pressure drops across the filter may increase, or a filter may degrade. These conditions can then cause polymer shearing, microbubble formation, gel particle formation, and BARC chemical changes to occur before the BARC reaches the wafer. To investigate these possible interactions, an Entegris(R) IntelliGen(R) pump was installed on a TEL Mk8 TM track to see if the filtration process would have an effect on the BARC chemistry and coating defects. Various BARC chemicals such as DUV112 and DUV42P were pumped through various filter media having a variety of pore sizes at different filtration rates to investigate the interaction between the dispense process and the filtration process. The IntelliGen2 pump has the capability to filter the BARC independent of the dispense process. By using a designed experiment to look at various parameters such as dispense rate, filtration rate, and dispense volume, the effects of the complete pump system can be learned, and appropriate conditions can be applied to yield the cleanest BARC coating process. Results indicate that filtration rate and filter pore size play a dramatic role in the defect density on a coated wafer with the actual dispense properties such as dispense wafer speed and dispense time playing a lesser role.

Dynamic filtration and static adsorption of lead ions in aqueous solution by use of blended polysulfone membranes with nano size MCM-41 particles coated by polyaniline.

PubMed

Toosi, Mohammad Reza; Emami, Mohammad Reza Sarmasti; Hajian, Sudeh

2018-05-11

MCM-41 mesopore was prepared by hydrothermal method and used for synthesis of polyaniline/MCM-41 nanocomposite via in situ polymerization. The nanocomposite was blended with polysulfone to prepare mixed matrix membrane in different content of nanocomposite by phase inversion method. Structural and surface properties of the samples were characterized by SEM, XRD, FTIR, AFM, TGA, BET, and zeta potential measurements. Effect of the nanocomposite content on the hydrophilicity, porosity, and permeability of the membrane was determined. Membrane performance was evaluated for removal of lead ions in dynamic filtration and static adsorption. The membranes were found as effective adsorptive filters for removal of lead ions via interactions between active sites of nanocomposite in membrane structure and lead ions during filtration. Results of batch experiments proved adsorptive mechanism of membranes for removal of lead ions with the maximum adsorption capacity of 19.6 mg/g.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sievers, David A.; Kuhn, Erik M.; Tucker, Melvin P.

In this study, the reaction conditions used during dilute-acid pretreatment of lignocellulosic biomass control the carbohydrate digestion yield and also hydrolyzate properties. Depending on the conversion route of interest, solid-liquid separation (SLS) may be required to split the hemicellulose-rich liquor from the cellulose-rich insoluble solids, and slurry properties are important for SLS. Corn stover was pretreated at different reaction conditions and the slurries were assessed for conversion yield and filtration performance. Increasing pretreatment temperature reduced the solids mean particle size and resulted in slower slurry filtration rates when vacuum filtered or pressure filtered. Corn stover pretreated at 165 °C formore » 10 min and with 1% H 2SO 4 exhibited the highest xylose yield and best filtration performance with a no-wash filtration rate of 80 kg/h m 2 and cake permeability of 15 x 10 -15.« less

Mitigation of radon and thoron decay products by filtration.

PubMed

Wang, Jin; Meisenberg, Oliver; Chen, Yongheng; Karg, Erwin; Tschiersch, Jochen

2011-09-01

Inhalation of indoor radon ((222)Rn) and thoron ((220)Rn) decay products is the most important source of exposure to ionizing radiation for the human respiratory tract. Decreasing ventilation rates due to energy saving reasons in new buildings suggest additional active mitigation techniques to reduce the exposure in homes with high radon and thoron concentrations but poor ventilation. Filtration techniques with HEPA filters and simple surgical mask material have been tested for their potential to reduce the indoor exposure in terms of the total effective dose for mixed radon and thoron indoor atmospheres. The tests were performed inside an experimental room providing stable conditions. Filtration (at filtration rates of 0.2 h(-1) and larger) removes attached radon and thoron decay products effectively but indoor aerosol as well. Therefore the concentration of unattached decay products (which have a higher dose coefficient) may increase. The decrease of the attached decay product concentrations could be theoretically described by a slowly decreasing exponential process. For attached radon decay products, it exhibited a faster but weaker removal process compared to attached thoron decay products (-70% for attached radon decay products and -80% for attached thoron decay products at a filtration rate of 0.5 h(-1) with an HEPA filter). The concentration of unattached thoron decay products increased distinctly during the filtration process (+300%) while that of unattached radon decay products rose only slightly though at a much higher level (+17%). In the theoretical description these observed differences could be attributed to the different half-lives of the nuclides. Considering both effects, reduced attached and increased unattached decay product concentrations, filtration could significantly decrease the total effective dose from thoron whereas the overall effect on radon dose is small. A permanent filtration is recommended because of the slow decrease of the thoron decay product concentrations. Copyright © 2011 Elsevier B.V. All rights reserved.

Mechanical Clogging Processes in Unconsolidated Porous Media Near Pumping Wells

NASA Astrophysics Data System (ADS)

de Zwart, B.; Schotting, R.; Hassanizadeh, M.

2003-12-01

In the Netherlands water supply companies produce over more than one billion cubic meters of drinking water every year. About 2500 water wells are used to pump up the groundwater from aquifers in the Dutch subsurface. More than 50% of these wells will encounter a number of technical problems during their lifetime. The main problem is the decrease in capacity due to well clogging. Clogging shows up after a number of operation years and results in extra, expensive cleaning operations and in early replacement of the pumping wells. This problem has been acknowledged by other industries, for example the metal, petroleum, beer industry and underground storage projects. Well clogging is the result of a number of interacting mechanisms creating a complex problem in the subsurface. In most clogging cases mechanical mechanisms are involved. A large number of studies have been performed to comprehend these processes. Investigations on mechanical processes are focused on transport of small particles through pores and deposition of particles due to physical or physical-chemical processes. After a period of deposition the particles plug the pores and decrease the permeability of the medium. Particle deposition in porous media is usually modelled using filtration theory. In order to get the dynamics of clogging this theory is not sufficient. The porous media is continuously altered due to deposition and mobilization. Therefore the capture characteristics will also continuously change and deposition rates will change in time. A new formula is derived to describe (re)mobilization of particles and allow changing deposition rates. This approach incorporates detachment and reattachment of deposited particles. This work also includes derivation of the filtration theory in radial coordinates. A comparison between the radial filtration theory and the new formula will be shown.

A Continuous Procedure Based on Column Chromatography to Purify Anthocyanins from Schisandra chinensis by a Macroporous Resin plus Gel Filtration Chromatography.

PubMed

Yue, Daran; Yang, Lei; Liu, Shouxin; Li, Jian; Li, Wei; Ma, Chunhui

2016-02-06

In our previous study, as natural food colorants and antioxidants, the color and content stabilities of Schisandra chinensis (S. chinensis) anthocyanins were investigated. In this work, the purification process parameters of S. chinensis anthocyanins using a macroporous resin and gel filtration chromatography were evaluated. The optimized parameters of static adsorption and desorption were as follows. The selected resin is HPD-300 (nonpolar copolymer styrene type resin), and the anthocyanins adsorption saturation capacity of HPD-300 resin was 0.475 mg/g dry resin. Adsorption time was 4 h, and 0.517 mg/mL of S. chinensis anthocyanins was adsorbed on the resin column with a flow rate of 39 mL/h (3 BV/h). After adsorption, the anthocyanins were completely desorpted with 2.5 BV of 90% (v/v) ethanol solution, and the desorption flow rate was 13 mL/h (1 BV/h). After purification by dynamic adsorption and desorption, the anthocyanins content in the effluent increased from 47.6 mg/g to 128.4 mg/g, the purity of anthocyanins increased six-fold from 5.08% to 30.43%, and the anthocyanins recovery was 96.5%. The major constituent of S. chinensis anthocyanins was isolated with Bio-Gel P2 gel filtration chromatography, and it was detected by liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS) as cyanidin-3-O-xylosylrutinoside. Moreover, the antioxidant activities of S. chinensis anthocyanins were investigated. After purification using the HPD-300 resin, the antioxidant activities of anthocyanins were increased 1.2-fold (FRAP) and 1.7-fold (ABTS).

Preliminary Findings of Serum Creatinine and Estimated Glomerular Filtration Rate (eGFR) in Adolescents with Intellectual Disabilities

ERIC Educational Resources Information Center

Lin, Jin-Ding; Lin, Lan-Ping; Hsieh, Molly; Lin, Pei-Ying

2010-01-01

The present study aimed to describe the kidney function profile--serum creatinine and estimated glomerular filtration rate (eGFR), and to examine the relationships of predisposing factors to abnormal serum creatinine in people with intellectual disabilities (ID). Data were collected by a cross-sectional study of 827 aged 15-18 years adolescents…

Effect of filter media size, mass flow rate and filtration stage number in a moving-bed granular filter on the yield and properties of bio-oil from fast pyrolysis of biomass.

PubMed

Paenpong, Chaturong; Inthidech, Sudsakorn; Pattiya, Adisak

2013-07-01

Fast pyrolysis of cassava rhizome was performed in a bench-scale fluidised-bed reactor unit incorporated with a cross-flow moving-bed granular filter. The objective of this research was to examine several process parameters including the granular size (425-1160 μm) and mass flow rate (0-12 g/min) as well as the number of the filtration stages (1-2 stages) on yields and properties of bio-oil. The results showed that the bio-oil yield decreased from 57.7 wt.% to 42.0-49.2 wt.% when increasing the filter media size, the mass flow rate and the filtration stage number. The effect of the process parameters on various properties of bio-oil is thoroughly discussed. In general, the bio-oil quality in terms of the solids content, ash content, initial viscosity, viscosity change and ageing rate could be enhanced by the hot vapour granular filtration. Therefore, bio-oil of high stability could be produced by the pyrolysis reactor configuration designed in this work. Copyright © 2013 Elsevier Ltd. All rights reserved.

A study of the role of renal nerves in the renal responses to 60° head-up tilt in the anaesthetized dog

PubMed Central

DiBona, G. F.; Johns, E. J.

1980-01-01

1. Renal responses to 10 min of 60° head-up tilt were measured in anaesthetized dogs in which renal perfusion pressure was maintained at a relatively constant value. 2. Tilting was associated with a fall in systemic blood pressure and an increase in heart rate. Renal blood flow and glomerular filtration rate remained constant while there was a significant decrease in both absolute and fractional excretion of sodium. 3. Animals which had undergone acute renal denervation were tilted. The cardiovascular responses were similar to intact animals. A fall in renal blood flow was observed but the glomerular filtration rate was maintained at a steady value during tilting. The decreased renal tubular excretion of sodium measured in intact animals was abolished. 4. Alpha-adrenergic blockade of the kidney was achieved by infusion of phentolamine into the renal artery. Tilting of these animals caused cardiovascular changes similar to those observed in control animals but renal blood flow, glomerular filtration rate and sodium handling remained unchanged. 5. Animals in which both carotid sinuses had been acutely denervated were tilted. Systemic blood pressure fell as in intact animals, but the rise in heart rate was significantly less. Renal blood flow, glomerular filtration rate and the rate of sodium excretion were unchanged. 6. A 10 min period of 60° head-up tilt in anaesthetized dogs resulted in an unchanged renal blood flow and glomerular filtration rate which was associated with a decrease in both fractional excretion of sodium and sodium excretion. The renal sympathetic nerves were shown to be responsible for these changes in tubular sodium handling which appeared to exert their action via renal tubular α-adrenergic receptors. This activation of the renal nerves appeared to be mediated by the carotid sinus baroreceptor reflex. PMID:7381761

Modified dixon‐based renal dynamic contrast‐enhanced MRI facilitates automated registration and perfusion analysis

PubMed Central

Leiner, Tim; Vink, Eva E.; Blankestijn, Peter J.; van den Berg, Cornelis A.T.

2017-01-01

Purpose Renal dynamic contrast‐enhanced (DCE) MRI provides information on renal perfusion and filtration. However, clinical implementation is hampered by challenges in postprocessing as a result of misalignment of the kidneys due to respiration. We propose to perform automated image registration using the fat‐only images derived from a modified Dixon reconstruction of a dual‐echo acquisition because these provide consistent contrast over the dynamic series. Methods DCE data of 10 hypertensive patients was used. Dual‐echo images were acquired at 1.5 T with temporal resolution of 3.9 s during contrast agent injection. Dixon fat, water, and in‐phase and opposed‐phase (OP) images were reconstructed. Postprocessing was automated. Registration was performed both to fat images and OP images for comparison. Perfusion and filtration values were extracted from a two‐compartment model fit. Results Automatic registration to fat images performed better than automatic registration to OP images with visible contrast enhancement. Median vertical misalignment of the kidneys was 14 mm prior to registration, compared to 3 mm and 5 mm with registration to fat images and OP images, respectively (P = 0.03). Mean perfusion values and MR‐based glomerular filtration rates (GFR) were 233 ± 64 mL/100 mL/min and 60 ± 36 mL/minute, respectively, based on fat‐registered images. MR‐based GFR correlated with creatinine‐based GFR (P = 0.04) for fat‐registered images. For unregistered and OP‐registered images, this correlation was not significant. Conclusion Absence of contrast changes on Dixon fat images improves registration in renal DCE MRI and enables automated postprocessing, resulting in a more accurate estimation of GFR. Magn Reson Med 80:66–76, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. PMID:29134673

Estimation of single-kidney glomerular filtration rate without exogenous contrast agent.

PubMed

He, Xiang; Aghayev, Ayaz; Gumus, Serter; Ty Bae, K

2014-01-01

Measurement of single-kidney filtration fraction and glomerular filtration rate (GFR) without exogenous contrast is clinically important to assess renal function and pathophysiology, especially for patients with comprised renal function. The objective of this study is to develop a novel MR-based tool for noninvasive quantification of renal function using conventional MR arterial spin labeling water as endogenous tracer. The regional differentiation of the arterial spin labeling water between the glomerular capsular space and the renal parenchyma was characterized and measured according to their MR relaxation properties (T1ρ or T2 ), and applied to the estimation of filtration fraction and single-kidney GFR. The proposed approach was tested to quantify GFR in healthy volunteers at baseline and after a protein-loading challenge. Biexponential decay of the cortical arterial spin labeling water MR signal was observed. The major component decays the same as parenchyma water; the minor component decays much slower as expected from glomerular ultra-filtrates. The mean single-kidney GFR was estimated to be 49 ± 9 mL/min at baseline and increased by 28% after a protein-loading challenge. We developed an arterial spin labeling-based MR imaging method that allows us to estimate renal filtration fraction and singe-kidney GFR without use of exogenous contrast. Copyright © 2013 Wiley Periodicals, Inc.

Pharmacologic Atrial Natriuretic Peptide Reduces Human Leg Capillary Filtration

NASA Technical Reports Server (NTRS)

Watenpaugh, Donald E.; Vissing, Susanne F.; Lane, Lynda D.; Buckey, Jay C.; Firth, Brian G.; Erdman, William; Hargens, Alan R.; Blomqvist, C. Gunnar

1995-01-01

Atrial natriuretic peptide (ANP) is produced and secreted by atrial cells. We measured calf capillary filtration rate with prolonged venous-occlusion plethys-mography of supine health male subjects during pharmacologic infusion of ANP (48 pmol/kg/min for 15 min; n equals 6) and during placebo infusion (n equals 7). Results during infusions were compared to prior control measurements. ANP infusion increased plasma (ANP) from 30 plus or minus 4 to 2,568 plus or minus 595 pmol/L. Systemic hemoconcentration occurred during ANP infusion; mean hematocrit and plasma colloid osmotic pressure increased 4.6 and 11.3 percent respectively, relative to pre-infusion baseline values (p is less than 0.05). Mean calf filtration, however was significantly reduced from 0.15 to 0.08 ml/100 ml/min with ANP. Heart rate increased 20 percent with ANP infusion, wheras blood pressure was unchanged. Calf conductance (blood flow/arterial pressure) and venous compliance were unaffected by ANP infusion. Placebo infusion had no effect relative to prior baseline control measurements. Although ANP induced systemic capillary filtration, in the calf, filtration was reduced with ANP. Therefore, phamacologic ANP infusion enhances capillary filtration from the systemic circulation, perhaps at upper body or splanchic sites or both, while having the opposite effect in the leg.

Precise measurement of renal filtration and vascular parameters using a two-compartment model for dynamic contrast-enhanced MRI of the kidney gives realistic normal values.

PubMed

Tofts, Paul S; Cutajar, Marica; Mendichovszky, Iosif A; Peters, A Michael; Gordon, Isky

2012-06-01

To model the uptake phase of T(1)-weighted DCE-MRI data in normal kidneys and to demonstrate that the fitted physiological parameters correlate with published normal values. The model incorporates delay and broadening of the arterial vascular peak as it appears in the capillary bed, two distinct compartments for renal intravascular and extravascular Gd tracer, and uses a small-vessel haematocrit value of 24%. Four physiological parameters can be estimated: regional filtration K ( trans ) (ml min(-1) [ml tissue](-1)), perfusion F (ml min(-1) [100 ml tissue](-1)), blood volume v ( b ) (%) and mean residence time MRT (s). From these are found the filtration fraction (FF; %) and total GFR (ml min(-1)). Fifteen healthy volunteers were imaged twice using oblique coronal slices every 2.5 s to determine the reproducibility. Using parenchymal ROIs, group mean values for renal biomarkers all agreed with published values: K ( trans ): 0.25; F: 219; v ( b ): 34; MRT: 5.5; FF: 15; GFR: 115. Nominally cortical ROIs consistently underestimated total filtration (by ~50%). Reproducibility was 7-18%. Sensitivity analysis showed that these fitted parameters are most vulnerable to errors in the fixed parameters kidney T(1), flip angle, haematocrit and relaxivity. These renal biomarkers can potentially measure renal physiology in diagnosis and treatment. • Dynamic contrast-enhanced magnetic resonance imaging can measure renal function. • Filtration and perfusion values in healthy volunteers agree with published normal values. • Precision measured in healthy volunteers is between 7 and 15%.

Recent progress in cell-free solubilization of coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cohen, M.S.; Aronson, H.; Feldman, K.

1988-01-01

Low rank coal has been solubilized using cell-free filtrates separated from cultures of Polyporus versicolor. Solubilization has been obtained with neat filtrates and with fractions collected from the neat filtrates after gel permeation chromatography. The coal solubilizing enzymes have been collected in enriched fractions with gpc. This increased relative purity has allowed the determination of the average molecular weight of this enzyme by gel permeation chromatography and by polyacrylamide gel electrophoresis. Rates of coal solubilization are dependent on the size of coal particles, mass of coal, temperature, pH, concentration of the cell-free filtrate, and the concentration of several inorganic ions.

Xanthan gum recovery from fermentation broth using ultrafiltration: Kinetics and process evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lo, Y.M.; Yang, S.T.; Min, D.B.

1995-12-01

Ultrafiltration of xanthan gum solution as an alternative method to alcohol precipitation for xanthan gum recovery from dilute fermentation broth was studied. A polysulfone membrane (with 500,000 MWCO) hollow fiber (106 mil fiber diameter) tubular cartridge was used to concentrate xanthan broth from less than 3 (w/v) % to {approximately}13.5 (w/v) %, with the xanthan recovery yield of {approximately}95 % or higher. During ultrafiltration, the filtrate flux was one order of magnitude lower for xanthan broth than for water, However, the flux remained almost constant for xanthan concentrations up to {approximately}8%. It was then reduced dramatically as the xanthan concentrationmore » increased beyond 8%. The reduced filtrate flux was caused by the reduced pumping (shear) rate and higher viscosities at higher xanthan concentrations. At constant xanthan concentration, the filtrate flux remained almost unchanged for the entire period studied, suggesting that the process is not subject to membrane fouling. In general, the filtrate flux decreased with increasing the xanthan concentration and increased with increasing the pumping (shear) rate and the trans-membrane pressure difference. Changing the solution pH had a slight effect on the viscosity of xanthan solution, but did not affect the filtration performance. Even under high-shear-rate conditions, ultrafiltration did not give any adverse effects on the rheological properties and molecular weight of the xanthan polymer. Thus, ultra filtration can be used to concentrate xanthan broth from fermentation by a factor of four or higher and to reduce the subsequent alcohol recovery costs by at least 75 %.« less

Assessment of glomerular filtration rate measurement with plasma sampling: a technical review.

PubMed

Murray, Anthony W; Barnfield, Mark C; Waller, Michael L; Telford, Tania; Peters, A Michael

2013-06-01

This article reviews available radionuclide-based techniques for glomerular filtration rate (GFR) measurement, focusing on clinical indications for GFR measurement, ideal GFR radiopharmaceutical tracer properties, and the 2 most common tracers in clinical use. Methods for full, 1-compartment, and single-sample renal clearance characterization are discussed. GFR normalization and the role of GFR measurement in chemotherapy dosing are also considered.

Albuminuria and Glomerular Filtration Rate in Individuals with Type 1 Diabetes Mellitus: Contribution of Metabolic Syndrome.

PubMed

Uribe-Wiechers, Ana Cecilia; Janka-Zires, Marcela; Almeda-Valdés, Paloma; López-Gutiérrez, Joel; Gómez-Pérez, Francisco J

2015-01-01

The development of metabolic syndrome has been described in patients with type 1 diabetes mellitus as the disease progresses over time. The purpose of this study is to assess the relationship between metabolic syndrome, albuminuria, and glomerular filtration rate, as well as to determine the prevalence of metabolic syndrome, in a group of Mexican patients with type 1 diabetes mellitus. We conducted a cross-sectional study that included patients with type 1 diabetes mellitus who were diagnosed over 10 years ago and who are seen at the Diabetes Intensive Control Clinic of the Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran in Mexico City. The presence of metabolic syndrome was determined by using the National Cholesterol Education Program-Adult Treatment Panel III (ATP III) criteria. A total of 81 individuals were studied. The prevalence of metabolic syndrome was 18.5% (n = 15). A higher albuminuria was found in subjects with metabolic syndrome (34.9 mg/24 hours; 8.3-169.3) than in those without metabolic syndrome (9.0 mg/24 hours; 5.0-27.0; p = 0.02). Glomerular filtration rate was lower in patients with metabolic syndrome (95.3 ml/minute; [64.9-107.2] vs. 110.2 ml/minute [88.1-120.3]; p = 0.04). After classifying the population according to the number of metabolic syndrome criteria, a progressive increase in albuminuria and a progressive decrease in glomerular filtration rate were found with each additional metabolic syndrome criterion (p = 0.008 and p = 0.032, respectively). After adjusting for age, time from diagnosis, systolic blood pressure, triglycerides, HDL-cholesterol, and treatment with angiotensin receptor blockers or angiotensin converting enzyme inhibitors, we found that age, time from diagnosis, triglycerides, and HDL-cholesterol were independent factors associated with glomerular filtration rate (R2 = 0.286; p < 0.001). Metabolic syndrome was associated with a higher albuminuria and a reduction in glomerular filtration rate in patients with type 1 diabetes mellitus. Metabolic syndrome was present in 18.5% of this group of Mexican individuals with type 1 diabetes mellitus.

[Coupling AFM fluid imaging with micro-flocculation filtration process for the technological optimization].

PubMed

Zheng, Bei; Ge, Xiao-peng; Yu, Zhi-yong; Yuan, Sheng-guang; Zhang, Wen-jing; Sun, Jing-fang

2012-08-01

Atomic force microscope (AFM) fluid imaging was applied to the study of micro-flocculation filtration process and the optimization of micro-flocculation time and the agitation intensity of G values. It can be concluded that AFM fluid imaging proves to be a promising tool in the observation and characterization of floc morphology and the dynamic coagulation processes under aqueous environmental conditions. Through the use of AFM fluid imaging technique, optimized conditions for micro-flocculation time of 2 min and the agitation intensity (G value) of 100 s(-1) were obtained in the treatment of dye-printing industrial tailing wastewater by the micro-flocculation filtration process with a good performance.

Office and 24-hour heart rate and target organ damage in hypertensive patients

PubMed Central

2012-01-01

Background We investigated the association between heart rate and its variability with the parameters that assess vascular, renal and cardiac target organ damage. Methods A cross-sectional study was performed including a consecutive sample of 360 hypertensive patients without heart rate lowering drugs (aged 56 ± 11 years, 64.2% male). Heart rate (HR) and its standard deviation (HRV) in clinical and 24-hour ambulatory monitoring were evaluated. Renal damage was assessed by glomerular filtration rate and albumin/creatinine ratio; vascular damage by carotid intima-media thickness and ankle/brachial index; and cardiac damage by the Cornell voltage-duration product and left ventricular mass index. Results There was a positive correlation between ambulatory, but not clinical, heart rate and its standard deviation with glomerular filtration rate, and a negative correlation with carotid intima-media thickness, and night/day ratio of systolic and diastolic blood pressure. There was no correlation with albumin/creatinine ratio, ankle/brachial index, Cornell voltage-duration product or left ventricular mass index. In the multiple linear regression analysis, after adjusting for age, the association of glomerular filtration rate and intima-media thickness with ambulatory heart rate and its standard deviation was lost. According to the logistic regression analysis, the predictors of any target organ damage were age (OR = 1.034 and 1.033) and night/day systolic blood pressure ratio (OR = 1.425 and 1.512). Neither 24 HR nor 24 HRV reached statistical significance. Conclusions High ambulatory heart rate and its variability, but not clinical HR, are associated with decreased carotid intima-media thickness and a higher glomerular filtration rate, although this is lost after adjusting for age. Trial Registration ClinicalTrials.gov: NCT01325064 PMID:22439900

Fragility of foot process morphology in kidney podocytes arises from chaotic spatial propagation of cytoskeletal instability

PubMed Central

Deerinck, Thomas J.; Chen, Yibang; He, John C.; Ellisman, Mark H.; Iyengar, Ravi

2017-01-01

Kidney podocytes’ function depends on fingerlike projections (foot processes) that interdigitate with those from neighboring cells to form the glomerular filtration barrier. The integrity of the barrier depends on spatial control of dynamics of actin cytoskeleton in the foot processes. We determined how imbalances in regulation of actin cytoskeletal dynamics could result in pathological morphology. We obtained 3-D electron microscopy images of podocytes and used quantitative features to build dynamical models to investigate how regulation of actin dynamics within foot processes controls local morphology. We find that imbalances in regulation of actin bundling lead to chaotic spatial patterns that could impair the foot process morphology. Simulation results are consistent with experimental observations for cytoskeletal reconfiguration through dysregulated RhoA or Rac1, and they predict compensatory mechanisms for biochemical stability. We conclude that podocyte morphology, optimized for filtration, is intrinsically fragile, whereby local transient biochemical imbalances may lead to permanent morphological changes associated with pathophysiology. PMID:28301477

The relation of Complementary-Alternative Medicine use with glomerular filtration rate and depression in patients with chronic kidney disease at predialysis stage.

PubMed

Esen, Bennur; Atay, Ahmet Engin; Gokmen, Emel Saglam; Karakoc, Ayten; Sari, Hakan; Sarisakal, Samprie; Kahvecioglu, Serdar; Kayabasi, Hasan; Sit, Dede

2015-05-08

Complementary and alternative medicine is a broad field of health including all health care practices and methods; and their accompanying theories and beliefs. In the present study, we aimed to examine the frequency of complementary-alternative medicine use, and its relation with glomerular filtration rate and depression in patients with chronic kidney disease at predialysis stage. A total of 1053 predialysis patients; 518 female and 535 male, that were followed up with chronic kidney disease for at least 3 months were enrolled into the study. Demographic features, biochemical parameters and findings of physical examination were recorded. Their compliance to diet, and knowledge about disease were questioned. Beck depression inventory and questionnaire regarding to complementary-alternative medicine use were performed. The overall frequency of complementary-alternative medicine use was 40.3% . Total ratio of herbal products was 46%. Complementary-alternative medicine use was significantly more frequent in female or single patients, and patients that informed about chronic kidney disease or under strict diet (p:0.007, p:0.016, p:0.02, p:0.016; respectively). When glomerular filtration rate of participants were considered, complementary-alternative medicine use was similar in different stages of kidney disease. Depression was observed in 41.9% of patients and significantly frequent in patients with alternative method use (p:0.002). Depression score was higher as creatinine increases and glomerular filtration rate decreases (p:0.002; r: 0,093). We determined that complementary-alternative medicine use gradually increases at predialysis stage as glomerular filtration rate decreases and there is a strict relation between complementary-alternative medicine use and depression or female gender. Disorder related stressors may lead to seeking of alternative methods. This article is protected by copyright. All rights reserved.

Interaction of the renin-angiotensin system and the renal nerves in the regulation of rat kidney function.

PubMed Central

Handa, R K; Johns, E J

1985-01-01

Stimulation of the renal sympathetic nerves in pentobarbitone anaesthetized rats achieved a 13% reduction in renal blood flow, did not change glomerular filtration rate, but reduced urine flow by 37%, absolute sodium excretion by 37%, and fractional sodium excretion by 34%. Following inhibition of converting enzyme with captopril (0.38 mmol kg-1 h-1), similar nerve stimulation reduced both renal blood flow and glomerular filtration rate by 16%, and although urine flow and absolute sodium excretion fell by 32 and 31%, respectively, the 18% fall in fractional sodium excretion was significantly less than that observed in the absence of captopril. Renal nerve stimulation at low levels, which did not change either renal blood flow or glomerular filtration rate, reduced urine flow, and absolute and fractional sodium excretions by 25, 26 and 23%, respectively. In animals receiving captopril at 0.38 mmol kg-1 h-1, low-level nerve stimulation caused small increases in glomerular filtration rate of 7% and urine flow of 12%, but did not change either absolute or fractional sodium excretions. At one-fifth the dose of captopril (0.076 mmol kg-1 h-1), low-level nerve stimulation did not change renal haemodynamics but decreased urine flow, and absolute and fractional sodium excretions by 10, 10 and 8%, respectively. These results showed that angiotensin II production was necessary for regulation of glomerular filtration rate in the face of modest neurally induced reductions in renal blood flow and was compatible with an intra-renal site of action of angiotensin II preferentially at the efferent arteriole. They also demonstrated that in the rat the action of the renal nerves to decrease sodium excretion was dependent on angiotensin II. PMID:3005558

Fluorescence-enhanced europium complexes for the assessment of renal function

NASA Astrophysics Data System (ADS)

Chinen, Lori K.; Galen, Karen P.; Kuan, K. T.; Dyszlewski, Mary E.; Ozaki, Hiroaki; Sawai, Hiroaki; Pandurangi, Raghootama S.; Jacobs, Frederick G.; Dorshow, Richard B.; Rajagopalan, Raghavan

2008-02-01

Real-time, non-invasive assessment of glomerular filtration rate (GFR) is essential not only for monitoring critically ill patients at the bedside, but also for staging and monitoring patients with chronic kidney disease. In our pursuit to develop exogenous luminescent probes for dynamic optical monitoring of GFR, we have prepared and evaluated Eu 3+ complexes of several diethylenetriamine pentaacetate (DTPA)-monoamide ligands bearing molecular "antennae" to enhance metal fluorescence via the intramolecular ligand-metal fluorescence resonance energy transfer (FRET) process. The results show that Eu-DTPA-monoamide complex 13a, which contains a quinoxanlinyl antenna, exhibits large (c.a. 2700-fold) Eu 3+ fluorescence enhancement over Eu-DTPA (4c). Indeed, complex 13a exhibits the highest fluorescent enhancement observed thus far in the DTPA-type metal complexes. The renal clearance profile of the corresponding radioactive 111In complex 13c is similar to that of 111In-DTPA, albeit 13c clears slower than 111In-DTPA. The biodistribution data indicates that 13c, and, by inference, 13a clear via a complex mechanism that includes glomerular filtration.

Study the effect of polymers on the stability and rheological properties of oil-in-water (O/W) Pickering emulsion muds

NASA Astrophysics Data System (ADS)

Jha, Praveen Kumar; Mahto, Vikas; Saxena, Vinod Kumar

2018-05-01

A new type of oil-in-water (O/W) Pickering emulsion systems, which were prepared by polymers such as xanthan gum, carboxymethyl cellulose (CMC), and sodium lignosulfonate have been investigated for their properties as multifunctional emulsion muds with respect to rheological control and filtration control properties. Diesel oil was used as dispersed phase and KCl-brine as continuous phase in the developed emulsions. Initially, rheological parameters like apparent viscosity, plastic viscosity, gel strength, and filtration control properties were measured using recommended practices. Emulsion stability was analyzed using steady state shear stress-shear rate and oscillatory (dynamic) rheological measurement techniques. The emulsions were found to exhibit shear-thinning (pseudoplastic) behavior. Experiments conducted for oscillatory rheological measurements have shown that emulsions are stable as per the stability criteria G' (elastic modulus) > G'' (loss modulus) and both are independent of changing ω (Frequency). These fluids have shown stable properties upto 70°C which shows that they can be used as drilling muds for drilling oil and gas wells.

Quantifying Factors That Impact Riverbed Dynamic Permeability at a Riverbank Filtration Facility

NASA Astrophysics Data System (ADS)

Ulrich, C.; Hubbard, S. S.; Florsheim, J. L.; Rosenberry, D. O.; Borglin, S. E.; Zhang, Y.; Seymour, D.; Trotta, M.

2012-12-01

Previous modeling studies of the Wohler riverbank filtration system on the Russian River, California suggested that riverbed and aquifer permeability both influence the development of a pumping-induced unsaturated zone below the riverbed, which affects water produced through large radial water-supply collector wells that extend beneath and adjacent to the river. In particular, previous work suggests that riverbed permeability is influenced by interaction between pumping and river stage that is controlled by a downstream temporary inflatable dam during the summer low flow period. We hypothesize that raising the dam may instead lead to deposition of fine-grained sediment and/or accumulation of biota, both of which decrease riverbed permeability in the vicinity of the collector wells. To test this hypothesis, we are monitoring streambed permeability and seepage as a function of river stage and dam operation. We are using multiple methods to monitor the hydrological, sedimentological and geomorphic dynamics, including: seepage meters, sediment traps, cryogenic coring, ground penetrating radar, electrical resistance tomography, riverbed topography, piezometers, and thermistors. Here we discuss the use of this novel suite of methods to quantify dynamic riverbed permeability, how it relates to dam operation, and determine the key controls on permeability (i.e., biotic or abiotic). These results are expected to improve the overall understanding of riverbed permeability dynamics associated with Riverbank filtration. The results are also expected to be transferable to the project sponsors, the Sonoma County Water Agency, toward the development of an optimal pumping and dam operation schedule.

In-line filtration minimizes organ dysfunction: new aspects from a prospective, randomized, controlled trial.

PubMed

Boehne, Martin; Jack, Thomas; Köditz, Harald; Seidemann, Kathrin; Schmidt, Florian; Abura, Michaela; Bertram, Harald; Sasse, Michael

2013-02-06

Infused particles induce thrombogenesis, impair microcirculation and modulate immune response. We have previously shown in critically ill children, that particle-retentive in-line filtration reduced the overall complication rate of severe events, length of stay and duration of mechanical ventilation. We now evaluated the influence of in-line filtration on different organ function and thereby elucidated the potential underlying pathophysiological effects of particle infusion. In this single-centre, prospective, randomized controlled trial 807 critically ill children were assigned to either control (n = 406) or filter group (n = 401), the latter receiving in-line filtration for complete infusion therapy. Both groups were compared regarding the differences of incidence rates and its 95% confidence interval (CI) of different organ dysfunction as defined by the International Pediatric Sepsis Consensus Conference 2005. The incidence rates of respiratory (-5.06%; 95% CI, -9.52 to -0.59%), renal (-3.87%; 95% CI, -7.58 to -0.15%) and hematologic (-3.89%; 95% CI, -7.26 to -0.51%) dysfunction were decreased in the filter group. No difference was demonstrated for the occurrence rates of cardiovascular, hepatic, or neurologic dysfunction between both groups. In-line filtration has beneficial effects on the preservation of hematologic, renal and respiratory function in critically ill patients. The presented clinical data further support our hypothesis regarding potential harmful effects of particles. In critically ill patients infused particles may lead to further deterioration of the microcirculation, induce a systemic hypercoagulability and inflammation with consecutive negative effects on organ function. ClinicalTrials.gov number; NCT00209768.

A 68-year old male presenting with rhabdomyolysis-associated acute kidney injury following concomitant use of elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate and pravastatin/fenofibrate: a case report.

PubMed

Suttels, Veronique; Florence, Eric; Leys, John; Vekemans, Marc; Van den Ende, Jef; Vlieghe, Erika; Kenyon, Chris

2015-09-08

We present what we believe to be the first case in the literature of rhabdomyolysis-induced renal failure caused by a probable drug interaction between elvitegravir/cobicistat/emtricitabine/tenofovir disoproxil fumarate (EVG/COBI/FTC/TDF) and pravastatin/fenofibrate. A 68-year old Caucasian man presented with progressive pain in both legs two weeks after commencing treatment with EVG/COBI/FTC/TDF. He was found to have biochemical evidence of rhabdomyolysis and acute renal failure. We emphasize the need for post marketing surveillance of adverse effects of new products. Pharmacokinetic studies are necessary to investigate the levels of pravastatin in patients taking COBI and fenofibrate with and without other comorbidities. Meanwhile, we suggest that creatine kinase levels should be monitored and patients advised to report myalgias when using concomitant EVG/COBI/FTC/TDF and pravastatin/fenofibrate. This case serves as an important reminder to use estimated glomerular filtration rates rather than serum creatinine levels when choosing new medications. If potentially nephrotoxic combinations are started in patients with borderline estimated glomerular filtration rates, it may be prudent to check these filtration rates more frequently than usual. In patients with reduced estimated glomerular filtration rates, potentially nephrotoxic combinations should be avoided wherever possible.

Water filtration rate and infiltration/accumulation of low density lipoproteins in 3 different modes of endothelial/smooth muscle cell co-cultures.

PubMed

Ding, ZuFeng; Fan, YuBo; Deng, XiaoYan

2009-11-01

Using different endothelial/smooth muscle cell co-culture modes to simulate the intimal structure of blood vessels, the water filtration rate and the infiltration/accumulation of LDL of the cultured cell layers were studied. The three cell culture modes of the study were: (i) The endothelial cell monolayer (EC/Phi); (ii) endothelial cells directly co-cultured on the smooth muscle cell monolayer (EC-SMC); (iii) endothelial cells and smooth muscle cells cultured on different sides of a Millicell-CM membrane (EC/SMC). It was found that under the same condition, the water filtration rate was the lowest for the EC/SMC mode and the highest for the EC/Phi mode, while the infiltration/accumulation of DiI-LDLs was the lowest in the EC/Phi mode and the highest in the EC-SMC mode. It was also found that DiI-LDL infiltration/accumulation in the cultured cell layers increased with the increasing water filtration rate. The results from the in vitro model study therefore suggest that the infiltration/accumulation of the lipids within the arterial wall is positively correlated with concentration polarization of atherogenic lipids, and the integrity of the endothelium plays an important role in the penetration and accumulation of atherogenic lipids in blood vessel walls.

Forming "dynamic" membranes on stainless steel

NASA Technical Reports Server (NTRS)

Brandon, C. A.; Gaddis, J. L.

1979-01-01

"Dynamic" zirconium polyacrylic membrane is formed directly on stainless steel substrate without excessive corrosion of steel. Membrane is potentially useful in removal of contaminated chemicals from solution through reversed osmosis. Application includes use in filtration and desalination equipment, and in textile industry for separation of dyes from aqueous solvents.

Identifying, counting, and characterizing superfine activated-carbon particles remaining after coagulation, sedimentation, and sand filtration.

PubMed

Nakazawa, Yoshifumi; Matsui, Yoshihiko; Hanamura, Yusuke; Shinno, Koki; Shirasaki, Nobutaka; Matsushita, Taku

2018-07-01

Superfine powdered activated carbon (SPAC; particle diameter ∼1 μm) has greater adsorptivity for organic molecules than conventionally sized powdered activated carbon (PAC). Although SPAC is currently used in the pretreatment to membrane filtration at drinking water purification plants, it is not used in conventional water treatment consisting of coagulation-flocculation, sedimentation, and rapid sand filtration (CSF), because it is unclear whether CSF can adequately remove SPAC from the water. In this study, we therefore investigated the residual SPAC particles in water after CSF treatment. First, we developed a method to detect and quantify trace concentration of carbon particles in the sand filtrate. This method consisted of 1) sampling particles with a membrane filter and then 2) using image analysis software to manipulate a photomicrograph of the filter so that black spots with a diameter >0.2 μm (considered to be carbon particles) could be visualized. Use of this method revealed that CSF removed a very high percentage of SPAC: approximately 5-log in terms of particle number concentrations and approximately 6-log in terms of particle volume concentrations. When waters containing 7.5-mg/L SPAC and 30-mg/L PAC, concentrations that achieved the same adsorption performance, were treated, the removal rate of SPAC was somewhat superior to that of PAC, and the residual particle number concentrations for SPAC and PAC were at the same low level (100-200 particles/mL). Together, these results suggest that SPAC can be used in place of PAC in CSF treatment without compromising the quality of the filtered water in terms of particulate matter contamination. However, it should be noted that the activated carbon particles after sand filtration were smaller in terms of particle size and were charge-neutralized to a lesser extent than the activated carbon particles before sand filtration. Therefore, the tendency of small particles to escape in the filtrate would appear to be related to the fact that their small size leads to a low destabilization rate during the coagulation process and a low collision rate during the flocculation and filtration processes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Image perception by expert readers as a function of patient skin entrance dose levels in digital radiography

NASA Astrophysics Data System (ADS)

Lehnert, T.; Korkusuz, H.; Khan, F.; Vogl, T. J.; Mack, M. G.

2008-03-01

In this study, image quality was based on required clinical criteria, in order to investigate to what degree entrance dose could be lowered and what kind of added filtration can be used without impinging on radiologist confidence levels in diagnosing. Images were taken of extremities from a cadaver using stepwise decreasing dose levels and variation of added filtration (no filtration, aluminum, aluminum/copper) under digital projection radiography (Kodak DirectView DR7500). The starting point dose level for all body parts imaged was the current x-ray technique. Two experienced and two resident radiologists were presented the images in a blinded fashion and rated each with an image quality score from 1 to 9 indicated very satisfied and 1 as very unsatisfied indicating loss of diagnostic value. The readers were not aware of which dose level and added filtration corresponded to which image. Dose levels considered were 100%, 75%, 50% and 25% of the normal and customary x-ray techniques used for the particular body part and projection. Images were reviewed on a clinical diagnostic workstation with no time limits imposed. Readers were also able to change the image presentation by adjusting the window width and level. Without added filtration image quality mean score was rated with 6.3 (dose level 100%), 6.2 (dose level 75%), 5.3 (dose level 50%) and with 4.4 (dose level 25%). An added aluminum filtration induced an image quality mean score of 6.3 (dose level 100%), 6.0 (dose level 75%), 5.1 (dose level 50%) and of 4.2 (dose level 25%). Using aluminum/copper filtration image quality mean score was rated with 6.0 (dose level 100%), 6.1 (dose level 75%), 5.0 (dose level 50%) and with 3.8 (dose level 25%). Regardless of the added filtration a differentiation between dose levels 100% and 75% was possible in 38.9%, between dose levels 75% and 50% in 66.7%, and between dose levels 50% and 25% in 70.0% of the cases. It is possible, in the case of extremities, to lower entrance doses up to 75 % of the normal value, a reduction of 25% in dose, under simultaneous use of added aluminum or aluminum/copper filtration, without comprising the diagnostic value required.

Pig manure treatment by filtration.

PubMed

Kowalski, Zygmunt; Makara, Agnieszka; Matýsek, Dalibor; Hoffmann, Józef; Hoffmann, Krystyna

2013-01-01

A study of new pig manure treatment and filtration process was carried out. The advantage of the worked out technology is the method of incorporation of crystalline phase into solid organic part of manure. The obtained new solid phase of manure contains about 50% of crystalline phase forming a filtration aid that enables high effectiveness of manure filtration. The filtration rate of manure separation into solid and liquid fractions with pressure filter may achieve 1300-3000 kg/m(2)/h. The method makes it possible to maintain an overall average pollutant removal performance 90% for the chemical oxygen demand COD, > 99% for the suspended solids SS, to 47% for the total nitrogen content. The obtained results showed that the proposed technology being efficient and simple offers a possible solution to pig manure problems.

Use of hollow fiber membrane filtration for the removal of DMSO from platelet concentrates.

PubMed

Arnaud, F; Kapnik, E; Meryman, H T

2003-05-01

It has been hypothesized that, in addition to freezing injury, some damage to platelets may result from the cell packing that occurs during removal of the cryoprotectant. This study examined DMSO removal by fluid exchange across hollow-fiber (HF) filters as an alternative to centrifugation. The DMSO solution with or without cell suspension was passed once through the filter. The optimum exchange during unloading of DMSO was determined by varying the flow rates in the external and internal compartments of the HF filter. Initially, buffered solutions of a 5% DMSO solution in the absence of platelets were pumped into the fibers and exchanged against PBS. The residual DMSO was determined by osmometry. The exchange of DMSO across the membrane was flow dependent and also influenced by the chemical nature of the HF fibers. No protocol using a reasonable rate flow through the fibers removed more than 95% of the DMSO in a single pass. The optimum protocol was achieved with polysynthane fibers with an internal flow rate of approximately 20 mi/min and an external flow rate of 100 ml/min. Subsequently, frozen/thawed platelet concentrates in DMSO were washed using centrifugation and compared to the HF filtration method. Platelet quality was assayed by flow cytometry, cell count, morphology and osmotic stress test. Both filtration and centrifugal washing techniques resulted in comparable morphological scores and numbers of discoid cells. When agents reducing platelet activation were added, platelet quality was improved after washing by either technique. The lower platelet osmotic response with HF filtration than with centrifugation while using activation inhibitors was attributed to the remaining amount of the inhibitors. All other parameters tested were similar. The expression of CD62P was equivalent with both techniques, and centrifugation did not activate platelets more than filtration contrary to what was originally anticipated. In conclusion, platelet quality was comparable after washing by either technique but hollow fiber filtration does remove cryoprotectant more rapidly than does centrifugation.

Elucidating the effects of river fluctuation on microbial removal during riverbank filtration

NASA Astrophysics Data System (ADS)

Derx, J.; Sommer, R.; Farnleitner, A. H.; Blaschke, A. P.

2010-12-01

The transfer of microbial pathogens from surface or waste water can have adverse effects on groundwater quality at riverbank filtration sites. Previous studies on groundwater protection in sandy unconfined aquifers with the focus on virus transport and health based water quality targets, such as done in the Netherlands, revealed larger protection zones than zones limited by 60 days of groundwater travel time. The 60 days of travel time are the design criterion in Austria for drinking water protection. However, in gravel aquifers, microbial transport processes differ significantly to those in sandy aquifers. Preferential flow and aquifer heterogeneities dominate microbial transport in sandy gravels and gravel aquifers. Microbial mass transfer and dual domain transport models were used previously to reproduce these effects. Furthermore, microbial transport has mainly been studied in the field during steady state groundwater flow situations. Hence, previous microbial transport models have seldom accounted for transient groundwater flow conditions. These dynamic flow conditions could have immense effects on the fate of microorganisms because of the variations in flow velocities, which are dominating microbial transport. In the current study, we used a variably saturated, three-dimensional groundwater flow and transport model coupled to a hydrodynamic surface water model at a riverbank filtration site. With this model, we estimated the required groundwater protection zones based on 8 log10 viral reductions and compared them to the 60 days travel time zones. The 8 log10 removal steps were based on a preliminary microbial risk assessment scheme for enteroviruses at the riverbank infiltration sites. The groundwater protection zones were estimated for a set of well withdrawal rates, river fluctuation ranges and frequencies, river gradients and bank slopes. The river flow dynamics and the morphology of the riverbed and banks are potentially important factors affecting microbial transport processes during riverbank filtration, which were previously not accounted for. Acknowledgments We would like to thank the Austrian Science Funds FWF for financial support as part of the Doctoral program DK-plus W1219-N22 on Water Resource Systems and the Vienna Waterworks (MA31) as part of the GWRS-Vienna project. We would also like to thank the MA39 (IFUM) for helping at the preliminary risk assessment.

Quantifying oil filtration effects on bearing life

NASA Technical Reports Server (NTRS)

Needelman, William M.; Zaretsky, Erwin V.

1991-01-01

Rolling-element bearing life is influenced by the number, size, and material properties of particles entering the Hertzian contact of the rolling element and raceway. In general, rolling-element bearing life increases with increasing level of oil filtration. Based upon test results, two equations are presented which allow for the adjustment of bearing L(sub 10) or catalog life based upon oil filter rating. It is recommended that where no oil filtration is used catalog life be reduced by 50 percent.

Feasibility of bioengineered two-stages sequential batch reactor and filtration-adsorption process for complex agrochemical effluent.

PubMed

Manekar, Pravin; Biswas, Rima; Urewar, Chaitali; Pal, Sukdeb; Nandy, Tapas

2013-11-01

In the present study, the feasibility of a bioengineered two-stages sequential batch reactor (BTSSBR) followed by filtration-adsorption process was investigated to treat the agrochemical effluent by overcoming factor affecting process stability such as microbial imbalance and substrate sensitivity. An air stripper stripped 90% of toxic ammonia, and combined with other streams for bio-oxidation and filtration-adsorption. The BTSSBR system achieved bio-oxidation at 6 days hydraulic retention time by fending off microbial imbalance and substrate sensitivity. The maximum reduction in COD and BOD by heterotrophic bacteria in the first reactor was 87% and 90%, respectively. Removal of toxic ammoniacal-nitrogen by autotrophic bacteria in a post-second stage bio-oxidation was 97%. The optimum filtration and adsorption of pollutants were achieved at a filtration rate of 10 and 9 m(3)m(-2)h(-1), respectively. The treatment scheme comprising air stripper, BTSSBR and filtration-adsorption process showed a great promise for treating the agrochemical effluent. Copyright © 2013 Elsevier Ltd. All rights reserved.

Dynamic alteration in splenic function during acute falciparum malaria

DOE Office of Scientific and Technical Information (OSTI.GOV)

Looareesuwan, S.; Ho, M.; Wattanagoon, Y.

Plasmodium-infected erythrocytes lose their normal deformability and become susceptible to splenic filtration. In animal models, this is one mechanism of antimalarial defense. To assess the effect of acute falciparum malaria on splenic filtration, we measured the clearance of heated /sup 51/Cr-labeled autologous erythrocytes in 25 patients with acute falciparum malaria and in 10 uninfected controls. Two groups of patients could be distinguished. Sixteen patients had splenomegaly, markedly accelerated clearance of the labeled erythrocytes (clearance half-time, 8.4 +/- 4.4 minutes (mean +/- SD) vs. 62.5 +/- 36.5 minutes in controls; P less than 0.001), and a lower mean hematocrit than didmore » the patients without splenomegaly (P less than 0.001). In the nine patients without splenomegaly, clearance was normal. After institution of antimalarial chemotherapy, however, the clearance in this group accelerated to supernormal rates similar to those in the patients with splenomegaly, but without the development of detectable splenomegaly. Clearance was not significantly altered by treatment in the group with splenomegaly. Six weeks later, normal clearance rates were reestablished in most patients in both groups. We conclude that splenic clearance of labeled erythrocytes is enhanced in patients with malaria if splenomegaly is present and is enhanced only after treatment if splenomegaly is absent. Whether this enhanced splenic function applies to parasite-infected erythrocytes in patients with malaria and has any clinical benefit will require further studies.« less

Longitudinal development of renal damage and renal function in infants with high grade vesicoureteral reflux.

PubMed

Sjöström, Sofia; Jodal, Ulf; Sixt, Rune; Bachelard, Marc; Sillén, Ulla

2009-05-01

We sought to study renal abnormality and renal function through time in infants with high grade vesicoureteral reflux. This prospective observational study included 115 infants (80 boys and 35 girls) younger than 1 year with grade III to V vesicoureteral reflux. The diagnosis was made after prenatal ultrasound in 26% of the patients and after urinary tract infection in 71%. Patients were followed by renal scintigraphy, 51chromium edetic acid clearance and video cystometry. Median followup was 62 months. Renal abnormality, which was found in 90% of the children at followup, was generalized in 71% and focal in 29%. The abnormality was bilateral in 28% of the affected patients. Total glomerular filtration rate was less than 80% of expected in 30% of the patients. Single kidney function was less than 40% of expected total glomerular filtration rate in 71% of the patients. Renal status (parenchymal abnormality and function) remained unchanged through time in 84 of 108 available cases (78%), improved in 5 (5%) and deteriorated in 19 (18%). Predictive factors for deterioration were recurrent febrile urinary tract infection, bilateral abnormality and reduced total glomerular filtration rate. Deteriorated renal status was more common in cases diagnosed prenatally than in those detected after urinary tract infection. Among these infants with high grade vesicoureteral reflux renal abnormality was frequent and was associated with subnormal filtration of one of the kidneys. Decreased total glomerular filtration rate was seen in about a third of the patients. Overall deterioration of renal status was seen in only a fifth of the patients. Infection control seems to be an important factor to minimize the risk.

Removal of Cryptosporidium parvum in bank filtration systems

NASA Astrophysics Data System (ADS)

Harter, T.; Atwill, E. R.; Hou, L. L.

2003-04-01

The protozoan pathogen Cryptosporidium parvum is a leading cause of waterborne disease. Many surface water systems therefore depend on filtration systems, including bank filtration systems, for the removal of the pathogenic oocysts. To better understand the effectiveness, e.g., of bank filtration systems, we have implemented a series of columns studies under various environmental conditions (column length: 10 cm - 60 cm, flow rates: 0.7 m/d - 30 m/d, ionic strength: 0.01 - 100 mM, filter grain size: 0.2 - 2 mm, various solution chemistry). We show that classic colloid filtration theory is a reasonable tool for predicting the initial breakthrough of C. parvum in pulsed injections of the oocyst through sand columns, although the model does not account for the significant tailing that occurs in C. parvum transport. Application of colloid filtration theory to bank filtration system is further limited by the intrinsic heterogeneity of the geologic systems used for bank filtration. We couple filtration theory with a stochastic subsurface transport approach and with percolation theory to account for the effects of intrinsic heterogeneity. We find that a 1-log removal can be achieved even under relatively adverse conditions (low collision efficiency, high velocity) if 85% - 90% of the sedimentary hydrofacies located within the bank filtration system or of the coarsest known hydrofacies connecting the riverbed with the extraction system has a grain-size distribution with a 10% passing diameter equal to 1 mm. One millimeter is a standard sieve size in sediment analysis.

Treatment and potential reuse of greywater from schools: a pilot study.

PubMed

Alsulaili, Abdalrahman D; Hamoda, Mohamed F; Al-Jarallah, Rawa; Alrukaibi, Duaij

2017-05-01

This study presented performance data on a low cost and easy maintenance pilot system for on-site treatment and reuse of water collected from wash sinks and fountains, as major sources of greywater (GW) at schools. Various treatment options were studied including screening, sand filtration, chlorination, and UV disinfection operated at different flow rates. Results showed that filtration operated at low rates is very effective in total suspended solids (TSS) removal, while UV proved to be more effective than chlorination for reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total coliforms. Removal efficiencies up to 63%, 30% and 20% were obtained for TSS, COD and BOD, respectively and reductions of log TC (CFU/100 ml) from 6.5 to 2 were obtained at a filtration rate of 14 m 3 /d·m 2 . Treated effluent satisfied WHO standards for reclaimed water reuse in landscape irrigation and toilet flushing. The filtration-UV system is robust, showing the best and most reliable performance for low and high strength GW treatment even under a 10-fold increase in flow rate. A 5 m 3 /d pilot plant was developed for schools having 500 students and detailed cost-benefit analysis indicated a net saving value, a surplus of $1,600 per year, and pay back after 6 years and 11 months.

Effects of UVB radiation on grazing of two cladocerans from high-altitude Andean lakes

PubMed Central

Rejas, Danny

2017-01-01

Climate change and water extraction may result in increased exposition of the biota to ultraviolet-B radiation (UVB) in high-altitude Andean lakes. Although exposition to lethal doses in these lakes is unlikely, sub-lethal UVB doses may have strong impacts in key compartments such as zooplankton. Here, we aimed at determining the effect of sub-lethal UVB doses on filtration rates of two cladoceran species (Daphnia pulicaria and Ceriodaphnia dubia). We firstly estimated the Incipient Limiting Concentration (ILC) and the Gut Passage Time (GPT) for both species. Thereafter we exposed clones of each species to four increasing UVB doses (treatments): i) DUV-0 (Control), ii) DUV-1 (0.02 MJ m2), iii) DUV-2 (0.03 MJ m2) and iv) DUV-3 (0.15 MJ m2); and estimated their filtration rates using fluorescent micro-spheres. Our results suggest that increasing sub-lethal doses of UVB radiation may strongly disturb the structure and functioning of high-altitude Andean lakes. Filtration rates of D. pulicaria were not affected by the lowest dose applied (DUV-1), but decreased by 50% in treatments DUV-2 and DUV-3. Filtration rates for C. dubia were reduced by more than 80% in treatments DUV-1 and DUV-2 and 100% of mortality occurred at the highest UVB dose applied (DUV-3). PMID:28379975

Flexographic newspaper deinking : treatment of wash filtrate effluent by membrane technology

Treesearch

B. Chabot; G.A. Krishnagopalan; S. Abubakr

1999-01-01

Ultrafiltration was investigated as a means to remove flexographic ink pigments from wash filtrate effluent generated from various mixtures of flexographic and offset old newspapers from deinking operations. Membrane separation efficiency was assessed from permeate flux, fouling rate, and ease of membrane regeneration (cleaning). Ultrafiltration was capable of...

LES of Laminar-to-Turbulent Particle-Fluid Dynamics in Human and Nonhuman Primate Airways: Applications to Aerosolized Drug Delivery Animal Testing

NASA Astrophysics Data System (ADS)

Geisler, Taylor; Padhy, Sourav; Shaqfeh, Eric; Iaccarino, Gianluca

2016-11-01

Both the human health benefit and risk from the inhalation of aerosolized medications is often predicted by extrapolating experimental data taken using nonhuman primates to human inhalation. In this study, we employ Large Eddy Simulation to simulate particle-fluid dynamics in realistic upper airway models of both humans and rhesus monkeys. We report laminar-to-turbulent flow transitions triggered by constrictions in the upper trachea and the persistence of unsteadiness into the low Reynolds number bifurcating lower airway. Micro-particle deposition fraction and locations are shown to depend significantly on particle size. In particular, particle filtration in the nasal airways is shown to approach unity for large aerosols (8 microns) or high-rate breathing. We validate the accuracy of LES mean flow predictions using MRV imaging results. Additionally, particle deposition fractions are validated against experiments in 3 model airways.

[Pollution prevention and control of aqueous extract of astragali radix processed with ZrO2 inorganic ceramic membrane micro-filtration].

PubMed

Pan, Lin-Men; Huang, Min-Yan; Guo, Li-Wei

2012-11-01

To study the measures for preventing and controlling the pollution of aqueous extract of Astragali Radix proceeded with inorganic ceramic membrane micro-filtration, in order to find effective measures for preventing and controlling the membrane pollution. The resistance distribution, polymer removal and changes in physical and chemical parameters of the zirconium oxide film of different pore diameters were determined to analyze the state or location of pollutants as well as the regularity of formation. Meanwhile, recoil and ultrasonic physical measures were adopted to strengthen the membrane process, in order to explore the methods for preventing and controlling the membrane pollution. When 0.2 microm of ZrO2 micro-filtrated aqueous extract of Astragali Radix, the rate of pollution was as high as 44.9%. The hole blocking resistance and the concentration polarization resistance were the main filtration resistances, while the surface deposit resistance decreased with the increase in the membrane's hold diameter; after micro-filtration, the liquid turbidity significantly reduced, with slight changes in both pH and viscosity. The 0.2 microm ZrO2 micro-filtration membrane performed better than the 0.05 microm pore size membrane in terms of conductivity. The 0. 2 microm and 0.05 microm pore diameter membranes showed better performance in the removal of pectin. The ultrasonic measure to strengthen membranes is more suitable to this system, with a flux rate up by 41.7%. The membrane optimization process adopts appropriate measures for preventing and controlling the membrane pollution, in order to reduce the membrane pollution, recover membrane performance and increase filtration efficiency.

Maremar, prevalence of chronic kidney disease, how to avoid over-diagnosis and under-diagnosis.

PubMed

De Broe, Marc E; Gharbi, Mohammed Benghanem; Elseviers, Monique

2016-04-01

Chronic kidney disease is considered as a major public health problem. Recent studies mention a prevalence rate between 8%-12%. Several editorials, comments, short reviews described the weaknesses (lack of confirmation of proteinuria, and of chronicity of decreased estimated glomerular filtration rate) of a substantial number of studies and the irrational of using a single arbitrary set point, i.e. diagnosis of chronic kidney disease whenever the estimated glomerular filtration rate is less than 60mL/min/1.73m(2). Maremar (Maladies rénales chroniques au Maroc) is a prevalence study of chronic kidney disease, hypertension, diabetes and obesity in a randomized, representative, high response rate (85%), sample of the adult population of Morocco, strictly applying the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Compared to the vast majority of the available studies, Maremar has a low prevalence of chronic kidney disease (2.9% adjusted to the actual adult population of Morocco). The population pyramid, and particularly the confirmation of proteinuria and "chronicity" of the decreased estimated glomerular filtration rate are the main reasons for this low prevalence of chronic kidney disease. The choice of arbitrary single threshold of estimated glomerular filtration rate for classifying stage 3-5 chronic kidney disease inevitably leads to "over-diagnosis" (false positives) of the disease in the elderly, particularly those without proteinuria, hematuria or hypertension, and to "under-diagnosed" (false negatives) in younger individuals with an estimated glomerular filtration rate above 60mL/min/1.73m(2) and below the 3rd percentile of their age/gender category. There is an urgent need for quality studies using in a correct way the recent KDIGO guidelines when investigating the prevalence of chronic kidney disease, in order to avoid a 50 to 100% overestimation of a disease state with potential dramatic consequences. The combination of the general population screening encompassing four different major health problems in the same screening procedure, using the correct methodologies and procedures, combined with a prevention/follow-up program results in a clinically/scientifically relevant program. Copyright © 2016 Association Société de néphrologie. Published by Elsevier SAS. All rights reserved.

Suitability assessment of grey water quality treated with an upflow-downflow siliceous sand/marble waste filtration system for agricultural and industrial purposes.

PubMed

Chaabane, Safa; Riahi, Khalifa; Hamrouni, Hédi; Thayer, Béchir Ben

2017-04-01

The present study examines the suitability assessment of an upflow-downflow siliceous sand/marble waste filtration system for treatment and reuse of grey water collected from bathrooms of the student residential complex at the Higher Institute of Engineering Medjez El Bab (Tunisia). Once the optimization of grey water pre-treatment system has been determined, the filtration system was operated at different hydraulic loading rate and media filter proportions in order to assess the suitability of treated grey water for irrigational purpose according to salinity hazard, sodium hazard, magnesium hazard, permeability index, water infiltration rate, and widely used graphical methods. Suitability of the treated grey water for industrial purpose was evaluated in terms of foaming, corrosion, and scaling. Under optimal operational conditions, results reveals that treated grey water samples with an upflow-downflow siliceous sand/marble waste filtration system may be considered as a good and an excellent water quality suitable for irrigation purpose. However, treated grey water was found not appropriate for industrial purpose due to high concentrations of calcium and sodium that can generate foaming and scaling harm to boilers. These results suggest that treated grey water with an upflow-downflow siliceous sand/marble waste filtration system would support production when used as irrigation water.

Acute kidney injury and cardiovascular outcomes in acute severe hypertension.

PubMed

Szczech, Lynda A; Granger, Christopher B; Dasta, Joseph F; Amin, Alpesh; Peacock, W Frank; McCullough, Peter A; Devlin, John W; Weir, Matthew R; Katz, Jason N; Anderson, Frederick A; Wyman, Allison; Varon, Joseph

2010-05-25

Little is known about the association of kidney dysfunction and outcome in acute severe hypertension. This study aimed to measure the association between baseline chronic kidney disease (estimated glomerular filtration rate), acute kidney injury (AKI, decrease in estimated glomerular filtration rate > or =25% from baseline) and outcome in patients hospitalized with acute severe hypertension. The Studying the Treatment of Acute Hypertension (STAT) registry enrolled patients with acute severe hypertension, defined as > or =1 blood pressure measurement >180 mm Hg systolic and/or >110 mm Hg diastolic and treated with intravenous antihypertensive therapy. Data were compared across groups categorized by admission estimated glomerular filtration rate and AKI during admission. On admission, 79% of the cohort (n=1566) had at least mild chronic kidney disease (estimated glomerular filtration rate <60 mL/min in 46%, <30 mL/min in 22%). Chronic kidney disease patients were more likely to develop heart failure (P<0.0001), non-ST-elevation myocardial infarction (P=0.003), and AKI (P<0.007). AKI patients were at greater risk of heart failure and cardiac arrest (P< or =0.0001 for both). Subjects with AKI experienced higher mortality at 90 days (P=0.003). Any acute loss of estimated glomerular filtration rate during hospitalization was independently associated with an increased risk of death (odds ratio, 1.05; P=0.03 per 10-mL/min decline). Other independent predictors of mortality included increasing age (P<0.0001), male gender (P=0.016), white versus black race (P=0.003), and worse baseline kidney function (P=0.003). Chronic kidney disease is a common comorbidity among patients admitted with acute severe hypertension, and AKI is a frequent form of acute target organ dysfunction, particularly in those with baseline chronic kidney disease. Any degree of AKI is associated with a greater risk of morbidity and mortality.

Filtration rate dependence of hyaluronan reflection by joint-to-lymph barrier: evidence for concentration polarisation

PubMed Central

Sabaratnam, S; Mason, RM; Levick, JR

2004-01-01

Hyaluronan (HA), a component of synovial fluid, buffers fluid loss from joints. To explain this, a quantitative theory for HA concentration polarisation at a partially sieving synovial lining was developed. The theory predicts a fall in HA reflected fraction R with increased filtration rate. To test this, knees of anaesthetised rabbits were infused with HA and fluorescein–dextran (FD) at constant trans-synovial filtration rates of 6–89 μl min−1. Samples of femoral lymph, mixed intra-articular fluid and subsynovial fluid after ≥ 3 h were analysed by high-performance liquid chromatography. R was calculated as (1 – downstream/upstream concentration), using [FD] to adjust for joint lymph dilution in femoral lymph. Intra-articular HA concentration after ≥ 3 h, 0.47 ± 0.02 mg ml−1 (mean ±s.e.m., n = 31), exceeded the infusate concentration, 0.20 mg ml−1, while subsynovial and lymph [HA] were reduced relative to [FD]. The changes in [HA] demonstrated synovial molecular sieving of HA. R from cavity to lymph (Rlymph) fell monotonically from 0.93 at 6 μl min−1 to 0.14 at 89 μl min−1 (P < 0.0001, regression analysis, n = 33). R values calculated from the intra-articular HA accumulation (Rasp) or the low subsynovial concentrations (Rsyn) were similar negative functions of filtration rate. R for lymphatic capillary endothelium (Rendo), calculated from lymph/subsynovial concentration ratios, was effectively zero (−0.03 ± 0.18, n = 21), confirming that synovium, not initial lymphatic endothelium, is the reflection site. Logarithmic linearisation of the results evaluated the synovial HA reflection coefficient as 0.91. In conclusion, the existence of concentration polarisation during joint fluid drainage was supported by the demonstration of a negative relation between filtration rate and Rlymph, Rasp and Rsyn. PMID:15073278

Metabolic abnormalities associated with elevated serum cystatin C in adults with an estimated GFR ≥ 60 ml/min/1.73m2

PubMed Central

Muntner, Paul; Vupputuri, Suma; Coresh, Josef; Uribarri, Jaime; Fox, Caroline S.

2011-01-01

Elevated serum cystatin C may represent an early stage of kidney disease. It is unclear whether metabolic abnormalities typically seen in advanced chronic kidney disease are present in adults with estimated glomerular filtration rate ≥60 ml/min/1.73m2 and elevated cystatin C. Participants of the Third National Health and Nutrition Examination Survey (n=6722) were categorized into three groups: estimated glomerular filtration rate ≥ 60 ml/min/1.73m2 and cystatin C <1.09 mg/L (normal cystatin C); estimated glomerular filtration rate ≥60 ml/min/1.73m2 and cystatin C ≥1.09 mg/L (elevated cystatin C); and estimated glomerular filtration rate of 15-59 ml/min/1.73m2 (stage 3 or 4 chronic kidney disease). Among those with normal cystatin C, elevated cystatin C, and stage 3 or 4 chronic kidney disease, the age, race-ethnicity, sex standardized prevalence of serum hemoglobin <12 g/dL (<13 g/dL for men) was 4.3%, 8.2%, and 13.8%; serum uric acid ≥ 5.9 mg/dL (≥7.4 mg/dL for men) was 12.6%, 30.0%, and 45.0%; serum homocysteine ≥13 μmol/L was 12.1%, 25.1%, and 41.0%; serum phosphorus ≥3.9 mg/dL was 17.2%, 23.2%, and 25.8%; serum albumin <3.8 mg/dL was 14.5%, 20.0%, and 20.4%; plasma fibrinogen ≥352 mg/dL was 10.5%, 21.7%, and 23.2%; and C-reactive protein ≥1.0 g/dL was 7.5%, 22.5%, and 21.6% (each p-trend<0.001). Among adults with estimated glomerular filtration rate ≥60 ml/min/1.73m2, elevated serum cystatin C is associated with an increased prevalence of several metabolic abnormalities. PMID:19295502

Capillary filtration in venous hypertension. Comparison between the vacuum suction chamber (VSC) device and straingauge phlethysmography.

PubMed

Belcaro, G; Rulo, A; Renton, S

1992-01-01

To evaluate capillary filtration a group of normal subjects and two groups of subjects with venous incompetence (50 with deep and 50 with superficial incompetence) were studied with the vacuum suction chamber (VSC) device applied onto the internal perimalleolar region. This method was compared with straingauge plethysmography rate of ankle swelling (RAS). By the VSC the time taken for the weal to disappear (VSC time) was considered indicative of capillary filtration. The values obtained with the two methods were well related (r < 0.742) and there was a good separation between patients and normals. The separation between the two groups of patients was significantly better (p < 0.05) with the VSC time. In conclusion VSC time is a good indication of capillary filtration in comparison with straingauge plethysmography RAS. It may be used to assess variations in capillary filtration in venous hypertension and possibly to follow up the effects of treatments.

Membrane-less microfiltration using inertial microfluidics

PubMed Central

Warkiani, Majid Ebrahimi; Tay, Andy Kah Ping; Guan, Guofeng; Han, Jongyoon

2015-01-01

Microfiltration is a ubiquitous and often crucial part of many industrial processes, including biopharmaceutical manufacturing. Yet, all existing filtration systems suffer from the issue of membrane clogging, which fundamentally limits the efficiency and reliability of the filtration process. Herein, we report the development of a membrane-less microfiltration system by massively parallelizing inertial microfluidics to achieve a macroscopic volume processing rates (~ 500 mL/min). We demonstrated the systems engineered for CHO (10–20 μm) and yeast (3–5 μm) cells filtration, which are two main cell types used for large-scale bioreactors. Our proposed system can replace existing filtration membrane and provide passive (no external force fields), continuous filtration, thus eliminating the need for membrane replacement. This platform has the desirable combinations of high throughput, low-cost, and scalability, making it compatible for a myriad of microfiltration applications and industrial purposes. PMID:26154774

Experimental investigation of clogging dynamics in homogeneous porous medium

NASA Astrophysics Data System (ADS)

Shen, Jikang; Ni, Rui

2017-03-01

A 3-D refractive-index matching Lagrangian particle tracking (3D-RIM-LPT) system was developed to study the filtration and the clogging process inside a homogeneous porous medium. A small subset of particles flowing through the porous medium was dyed and tracked. As this subset was randomly chosen, its dynamics is representative of all the rest. The statistics of particle locations, number, and velocity were obtained as functions of different volumetric concentrations. It is found that in our system the clogging time decays with the particle concentration following a power law relationship. As the concentration increases, there is a transition from depth filtration to cake filtration. At high concentration, more clogged pores lead to frequent flow redirections and more transverse migrations of particles. In addition, the velocity distribution in the transverse direction is symmetrical around zero, and it is slightly more intermittent than the random Gaussian curve due to particle-particle and particle-grain interactions. In contrast, as clogging develops, the longitudinal velocity of particles along the mean flow direction peaks near zero because of many trapped particles. But at the same time, the remaining open pores will experience larger pressure and, as a result, particles through those pores tend to have larger longitudinal velocities.

Form, Function and Flow in the Plankton: Jet Propulsion and Filtration by Pelagic Tunicates

DTIC Science & Technology

2010-02-01

to become flattened when they are removed from the water. The flexibility of the test allows for deeper compressions with each pulse. Because the... Pipe jet experiments and studies with jet-propelled organisms have shown that the optimum F can   58 be affected by at least two phenomena: 1...has high filtration rates. Both of these traits are likely tied to the high pulsation rates in this species. Still, a complete picture of trade

Acoustic filtration and sedimentation of soot particles

NASA Astrophysics Data System (ADS)

Martin, K. M.; Ezekoye, O. A.

Removal of soot particles from a static chamber by an intense acoustic field is investigated. Combustion of a solid fuel fills a rectangular chamber with small soot particles, which sediment very slowly. The chamber is then irradiated by an intense acoustic source to produce a three dimensional standing wave field in the chamber. The acoustic excitation causes the soot particles to agglomerate, forming larger particles which sediment faster from the system. The soot also forms 1-2 cm disks, with axes parallel to the axis of the acoustic source, which are levitated by the sound field at half-wavelength spacing within the chamber. Laser extinction measurements are made to determine soot volume fractions as a function of exposure time within the chamber. The volume fraction is reduced over time by sedimentation and by particle migration to the disks. The soot disks are considered to be a novel mechanism for particle removal from the air stream, and this mechanism has been dubbed acoustic filtration. An experimental method is developed for comparing the rate of soot removal by sedimentation alone with the rate of soot removal by sedimentation and acoustic filtration. Results show that acoustic filtration increases the rate of soot removal by a factor of two over acoustically-induced sedimentation alone.

Hydrogeomorphology of the hyporheic zone: stream solute and fine particle interactions with a dynamic streambed

USGS Publications Warehouse

Harvey, J.W.; Drummond, J.D.; Martin, R.L.; McPhillips, L.E.; Packman, A.I.; Jerolmack, D.J.; Stonedahl, S.H.; Aubeneau, A.F.; Sawyer, A.H.; Larsen, L.G.; Tobias, C.R.

2012-01-01

Hyporheic flow in streams has typically been studied separately from geomorphic processes. We investigated interactions between bed mobility and dynamic hyporheic storage of solutes and fine particles in a sand-bed stream before, during, and after a flood. A conservatively transported solute tracer (bromide) and a fine particles tracer (5 μm latex particles), a surrogate for fine particulate organic matter, were co-injected during base flow. The tracers were differentially stored, with fine particles penetrating more shallowly in hyporheic flow and retained more efficiently due to the high rate of particle filtration in bed sediment compared to solute. Tracer injections lasted 3.5 h after which we released a small flood from an upstream dam one hour later. Due to shallower storage in the bed, fine particles were rapidly entrained during the rising limb of the flood hydrograph. Rather than being flushed by the flood, we observed that solutes were stored longer due to expansion of hyporheic flow paths beneath the temporarily enlarged bedforms. Three important timescales determined the fate of solutes and fine particles: (1) flood duration, (2) relaxation time of flood-enlarged bedforms back to base flow dimensions, and (3) resulting adjustments and lag times of hyporheic flow. Recurrent transitions between these timescales explain why we observed a peak accumulation of natural particulate organic matter between 2 and 4 cm deep in the bed, i.e., below the scour layer of mobile bedforms but above the maximum depth of particle filtration in hyporheic flow paths. Thus, physical interactions between bed mobility and hyporheic transport influence how organic matter is stored in the bed and how long it is retained, which affects decomposition rate and metabolism of this southeastern Coastal Plain stream. In summary we found that dynamic interactions between hyporheic flow, bed mobility, and flow variation had strong but differential influences on base flow retention and flood mobilization of solutes and fine particulates. These hydrogeomorphic relationships have implications for microbial respiration of organic matter, carbon and nutrient cycling, and fate of contaminants in streams.

Evaluation of the effects of the metals Cd, Cr, Pb and their mixture on the filtration and oxygen consumption rates in catarina scallop, Argopecten ventricosus juveniles.

PubMed

Sobrino-Figueroa, Alma S; Cáceres-Martinez, Carlos

2014-01-01

In this work, we evaluated the effect of sublethal concentrations ( LC25, LC10 and LC5) of cadmium, chromium, lead, and their mixture on the filtration rate and oxygen consumption rate of Catarina scallop, Argopecten ventricosus (Sowerby, 1842), juveniles, in order to evaluate the use of these biomarkers as a reliable tool in environmental monitoring studies, because these metals have been found at high levels in water and sediments in the Mexican Pacific systems. An inverse dose-response relationship was observed when metal concentration and exposure time increased, the filtration rate and oxygen consumption rate reduced. The physiological responses evaluated in this study were sufficiently sensitive to detect alterations in the organisms at 0.014 mg l(-1) Cd, 0.311 mg l(-1) Cr, 0.125 mg l(-1) Pb and 0.05 mg l(-1) Cd + Cr + Pb at 24 and 72 hrs. Cd showed the most drastic effect. The Catarina scallop juveniles were more sensitive to Cd, Cr and Pb as compared to other bivalves. The biomarkers evaluated are a reliable tool to carry out environmental monitoring studies.

The mechanism of the increase in glomerular filtration rate in the twelve-day pregnant rat.

PubMed Central

Baylis, C

1980-01-01

1. Whole kidney and micropuncture techniques were employed to investigate the determinants of glomerular ultrafiltration in virgin and 12-day pregnant rats. 2. A significant increase in whole kidney glomerular filtration rate (g.f.r.) and superficial cortical single nephron g.f.r. was noted in pregnant rats compared to virgins. 3. Increases in whole kidney and glomerular plasma flow rate also occurred in pregnancy which were in proportion to the increase in rate of filtration. No differences were noted in the hydrostatic and oncotic pressures which influence formation of glomerular ultrafiltrate in the superficial nephron population. 4. Reduction in arterial haematocrit and no change in mean red cell volume indicate that a plasma volume expansion has occurred by day 12 of pregnancy in the rat. 5. It is concluded that the increased g.f.r. seen in 12-day pregnant rats is exclusively the result of an increase in renal plasma flow rate (r.p.f.) since the other determinants of glomerular ultrafiltration are unaffected by pregnancy. The plasma volume expansion which also occurs must be, at least in part, responsible for the increase in r.p.f. PMID:7441561

Influence of linearly polarized near-infrared irradiation on deformability of human stored erythrocytes.

PubMed

Yokoyama, Kozo; Sugiyama, Kazuna

2003-02-01

To investigate the influence of linearly polarized near-infrared irradiation using the Super Lizer trade mark on deformability of human erythrocytes. Not only low-powered laser but also linearly polarized near-infrared beams have some biostimulation effects on various tissues. There were some reports of erythrocyte deformability improved by low-powered He-Ne laser irradiation. Human erythrocyte samples stored for three weeks were adjusted to 30% hematocrit. Erythrocyte deformability presented as the filter filtration rate was measured. There was no difference of the filter filtration rate between control group without irradiation and the group of 125 mJ/cm(2) exposure level at a wavelength of 830 nm. However, the groups of 625 and 1,250 mJ/cm(2) exposure levels at a wavelength of 830 nm showed higher filter filtration rates compared to the control group. Linearly polarized near-infrared irradiation in a range of 625-1,250 mJ/cm(2) exposure level at a wavelength of 830 nm improved deformability of human stored erythrocytes.

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house.

PubMed

Singer, B C; Delp, W W; Black, D R; Walker, I S

2017-07-01

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM 2.5 by 97-98% relative to outdoors. Supply filtration systems used little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, Brett C.; Delp, William W.; Black, Douglas R.

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration produced indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection whereas supply MERV16 filtration reduced PM 2.55 by 97-98% relative to outdoors. Supply filtration systems usedmore » little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 filters in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5. Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.« less

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

DOE Office of Scientific and Technical Information (OSTI.GOV)

Singer, B. C.; Delp, W. W.; Black, D. R.

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM 2.5 by 97-98% relative to outdoors. Supply filtration systems usedmore » little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 fil ter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.« less

Measured performance of filtration and ventilation systems for fine and ultrafine particles and ozone in an unoccupied modern California house

DOE PAGES

Singer, B. C.; Delp, W. W.; Black, D. R.; ...

2016-12-05

This study evaluated nine ventilation and filtration systems in an unoccupied 2006 house located 250 m downwind of the I-80 freeway in Sacramento, California. Systems were evaluated for reducing indoor concentrations of outdoor particles in summer and fall/winter, ozone in summer, and particles from stir-fry cooking. Air exchange rate was measured continuously. Energy use was estimated for year-round operation in California. Exhaust ventilation without enhanced filtration provided indoor PM 2.5 that was 70% lower than outdoors. Supply ventilation with MERV13 filtration provided slightly less protection, whereas supply MERV16 filtration reduced PM 2.5 by 97-98% relative to outdoors. Supply filtration systems usedmore » little energy but provided no benefits for indoor-generated particles. Systems with MERV13-16 fil ter in the recirculating heating and cooling unit (FAU) operating continuously or 20 min/h reduced PM 2.5 by 93-98%. Across all systems, removal percentages were higher for ultrafine particles and lower for black carbon, relative to PM 2.5 . Indoor ozone was 3-4% of outdoors for all systems except an electronic air cleaner that produced ozone. Filtration via the FAU or portable filtration units lowered PM 2.5 by 25-75% when operated over the hour following cooking. The energy for year-round operation of FAU filtration with an efficient blower motor was estimated at 600 kWh/year.« less

The impact of tabalumab on the kidney in systemic lupus erythematosus: results from two phase 3 randomized, clinical trials.

PubMed

Rovin, B H; Dooley, M A; Radhakrishnan, J; Ginzler, E M; Forrester, T D; Anderson, P W

2016-12-01

Tabalumab is a monoclonal antibody that neutralizes membrane and soluble B-cell activating factor. Two 52-week, randomized, double-blind, placebo controlled phase 3 trials evaluated the safety and efficacy of tabalumab in systemic lupus erythematosus. Patients with moderate to severe active systemic lupus erythematosus (without severe active lupus nephritis) were randomly assigned 1:1:1 to receive tabalumab (120 mg subcutaneously every 2 or 4 weeks) or placebo for 52 weeks. Serum creatinine concentration, estimated glomerular filtration rate, urine protein/creatinine ratio, renal flares and renal adverse events were determined monthly. Data were analyzed for the intent-to-treat population and for intent-to-treat patients with baseline urine protein/creatinine ratio >20 mg/mmol (intent-to-treat plus urine protein/creatinine ratio). The trials enrolled 2262 patients. At baseline, demographics, systemic lupus erythematosus disease activity, serum creatinine concentration, estimated glomerular filtration rate and urine protein/creatinine ratio were similar among the treatment arms (with the exception of disease duration). In the intent-to-treat and intent-to-treat plus urine protein/creatinine ratio populations, there were no differences between the arms in the baseline-to-endpoint change in serum creatinine concentration, glomerular filtration rate, urine protein/creatinine ratio, or renal flare rates. Tabalumab resulted in a significant B-cell reduction and decreased immunoglobulin G levels at both doses. Compared to placebo, tabalumab did not significantly affect the serum creatinine concentration, glomerular filtration rate, urine protein/creatinine ratio, or renal flare rates over 1 year in intent-to-treat or intent-to-treat plus urine protein/creatinine ratio patients. There were no significant renal safety signals.ClinicalTrials.gov identifiers: NCT01205438 and NCT01196091 Lupus (2016) 25, 1597-1601. © The Author(s) 2016.

Impacts of extreme flooding on riverbank filtration water quality.

PubMed

Ascott, M J; Lapworth, D J; Gooddy, D C; Sage, R C; Karapanos, I

2016-06-01

Riverbank filtration schemes form a significant component of public water treatment processes on a global level. Understanding the resilience and water quality recovery of these systems following severe flooding is critical for effective water resources management under potential future climate change. This paper assesses the impact of floodplain inundation on the water quality of a shallow aquifer riverbank filtration system and how water quality recovers following an extreme (1 in 17 year, duration >70 days, 7 day inundation) flood event. During the inundation event, riverbank filtrate water quality is dominated by rapid direct recharge and floodwater infiltration (high fraction of surface water, dissolved organic carbon (DOC) >140% baseline values, >1 log increase in micro-organic contaminants, microbial detects and turbidity, low specific electrical conductivity (SEC) <90% baseline, high dissolved oxygen (DO) >400% baseline). A rapid recovery is observed in water quality with most floodwater impacts only observed for 2-3 weeks after the flooding event and a return to normal groundwater conditions within 6 weeks (lower fraction of surface water, higher SEC, lower DOC, organic and microbial detects, DO). Recovery rates are constrained by the hydrogeological site setting, the abstraction regime and the water quality trends at site boundary conditions. In this case, increased abstraction rates and a high transmissivity aquifer facilitate rapid water quality recoveries, with longer term trends controlled by background river and groundwater qualities. Temporary reductions in abstraction rates appear to slow water quality recoveries. Flexible operating regimes such as the one implemented at this study site are likely to be required if shallow aquifer riverbank filtration systems are to be resilient to future inundation events. Development of a conceptual understanding of hydrochemical boundaries and site hydrogeology through monitoring is required to assess the suitability of a prospective riverbank filtration site. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Two-year analysis for predicting renal function and contralateral hypertrophy after robot-assisted partial nephrectomy: A three-dimensional segmentation technology study.

PubMed

Kim, Dae Keun; Jang, Yujin; Lee, Jaeseon; Hong, Helen; Kim, Ki Hong; Shin, Tae Young; Jung, Dae Chul; Choi, Young Deuk; Rha, Koon Ho

2015-12-01

To analyze long-term changes in both kidneys, and to predict renal function and contralateral hypertrophy after robot-assisted partial nephrectomy. A total of 62 patients underwent robot-assisted partial nephrectomy, and renal parenchymal volume was calculated using three-dimensional semi-automatic segmentation technology. Patients were evaluated within 1 month preoperatively, and postoperatively at 6 months, 1 year and continued up to 2-year follow up. Linear regression models were used to identify the factors predicting variables that correlated with estimated glomerular filtration rate changes and contralateral hypertrophy 2 years after robot-assisted partial nephrectomy. The median global estimated glomerular filtration rate changes were -10.4%, -11.9%, and -2.4% at 6 months, 1 and 2 years post-robot-assisted partial nephrectomy, respectively. The ipsilateral kidney median parenchymal volume changes were -24%, -24.4%, and -21% at 6 months, 1 and 2 years post-robot-assisted partial nephrectomy, respectively. The contralateral renal volume changes were 2.3%, 9.6% and 12.9%, respectively. On multivariable linear analysis, preoperative estimated glomerular filtration rate was the best predictive factor for global estimated glomerular filtration rate change on 2 years post-robot-assisted partial nephrectomy (B -0.452; 95% confidence interval -0.84 to -0.14; P = 0.021), whereas the parenchymal volume loss rate (B -0.43; 95% confidence interval -0.89 to -0.15; P = 0.017) and tumor size (B 5.154; 95% confidence interval -0.11 to 9.98; P = 0.041) were the significant predictive factors for the degree of contralateral renal hypertrophy on 2 years post-robot-assisted partial nephrectomy. Preoperative estimated glomerular filtration rate significantly affects post-robot-assisted partial nephrectomy renal function. Renal mass size and renal parenchyma volume loss correlates with compensatory hypertrophy of the contralateral kidney. Contralateral hypertrophy of the renal parenchyma compensates for the functional loss of the ipsilateral kidney. © 2015 The Japanese Urological Association.

Fluid balance, glomerular filtration rate, and urine output in dogs anesthetized for an orthopedic surgical procedure.

PubMed

Boscan, Pedro; Pypendop, Bruno H; Siao, Kristine T; Francey, Thierry; Dowers, Kristy; Cowgill, Larry; Ilkiw, Jan E

2010-05-01

To determine fluid retention, glomerular filtration rate, and urine output in dogs anesthetized for a surgical orthopedic procedure. 23 dogs treated with a tibial plateau leveling osteotomy. 12 dogs were used as a control group. Cardiac output was measured in 5 dogs, and 6 dogs received carprofen for at least 14 days. Dogs received oxymorphone, atropine, propofol, and isoflurane for anesthesia (duration, 4 hours). Urine and blood samples were obtained for analysis every 30 minutes. Lactated Ringer's solution was administered at 10 mL/kg/h. Urine output was measured and glomerular filtration rate was estimated. Fluid retention was measured by use of body weight, fluid balance, and bioimpedance spectroscopy. No difference was found among control, cardiac output, or carprofen groups, so data were combined. Median urine output and glomerular filtration rate were 0.46 mL/kg/h and 1.84 mL/kg/min. Dogs retained a large amount of fluids during anesthesia, as indicated by increased body weight, positive fluid balance, increased total body water volume, and increased extracellular fluid volume. The PCV, total protein concentration, and esophageal temperature decreased in a linear manner. Dogs anesthetized for a tibial plateau leveling osteotomy retained a large amount of fluids, had low urinary output, and had decreased PCV, total protein concentration, and esophageal temperature. Evaluation of urine output alone in anesthetized dogs may not be an adequate indicator of fluid balance.

Concentration of Enteroviruses, Adenoviruses, and Noroviruses from Drinking Water by Use of Glass Wool Filters▿

PubMed Central

Lambertini, Elisabetta; Spencer, Susan K.; Bertz, Phillip D.; Loge, Frank J.; Kieke, Burney A.; Borchardt, Mark A.

2008-01-01

Available filtration methods to concentrate waterborne viruses are either too costly for studies requiring large numbers of samples, limited to small sample volumes, or not very portable for routine field applications. Sodocalcic glass wool filtration is a cost-effective and easy-to-use method to retain viruses, but its efficiency and reliability are not adequately understood. This study evaluated glass wool filter performance to concentrate the four viruses on the U.S. Environmental Protection Agency contaminant candidate list, i.e., coxsackievirus, echovirus, norovirus, and adenovirus, as well as poliovirus. Total virus numbers recovered were measured by quantitative reverse transcription-PCR (qRT-PCR); infectious polioviruses were quantified by integrated cell culture (ICC)-qRT-PCR. Recovery efficiencies averaged 70% for poliovirus, 14% for coxsackievirus B5, 19% for echovirus 18, 21% for adenovirus 41, and 29% for norovirus. Virus strain and water matrix affected recovery, with significant interaction between the two variables. Optimal recovery was obtained at pH 6.5. No evidence was found that water volume, filtration rate, and number of viruses seeded influenced recovery. The method was successful in detecting indigenous viruses in municipal wells in Wisconsin. Long-term continuous filtration retained viruses sufficiently for their detection for up to 16 days after seeding for qRT-PCR and up to 30 days for ICC-qRT-PCR. Glass wool filtration is suitable for large-volume samples (1,000 liters) collected at high filtration rates (4 liters min−1), and its low cost makes it advantageous for studies requiring large numbers of samples. PMID:18359827

Continuous improvements of defectivity rates in immersion photolithography via functionalized membranes in point-of-use photochemical filtration

NASA Astrophysics Data System (ADS)

D'Urzo, Lucia; Bayana, Hareen; Vandereyken, Jelle; Foubert, Philippe; Wu, Aiwen; Jaber, Jad; Hamzik, James

2017-03-01

Specific "killer-defects", such as micro-line-bridges are one of the key challenges in photolithography's advanced applications, such as multi-pattern. These defects generate from several sources and are very difficult to eliminate. Pointof-use filtration (POU) plays a crucial role on the mitigation, or elimination, of such defects. Previous studies have demonstrated how the contribution of POU filtration could not be studied independently from photoresists design and track hardware settings. Specifically, we investigated how an effective combination of optimized photoresist, filtration rate, filtration pressure, membrane and device cleaning, and single and multilayer filter membranes at optimized pore size could modulate the occurrence of such defects [1, 2, 3 and 4]. However, the ultimate desired behavior for POU filtration is the selective retention of defect precursor molecules contained in commercially available photoresist. This optimal behavior can be achieved via customized membrane functionalization. Membrane functionalization provides additional non-sieving interactions which combined with efficient size exclusion can selectively capture certain defect precursors. The goal of this study is to provide a comprehensive assessment of membrane functionalization applied on an asymmetric ultra-high molecular weight polyethylene (UPE) membrane at different pore size. Defectivity transferred in a 45 nm line 55 nm space (45L/55S) pattern, created through 193 nm immersion (193i) lithography with a positive tone chemically amplified resist (PT-CAR), has been evaluated on organic under-layer coated wafers. Lithography performance, such as critical dimensions (CD), line width roughness (LWR) and focus energy matrix (FEM) is also assessed.

One-dimensional filtration of pharmaceutical grade phyllosilicate dispersions.

PubMed

Viseras, C; Cerezo, P; Meeten, G H; Lopez-Galindo, A

2001-04-17

The filtration behaviour of some clay-water dispersions was studied. Two Spanish fibrous phyllosilicates (sepiolite from Vicálvaro and palygorskite from Turón) and a commercial bentonite (Bentopharm UK) with similar sizes and different morphologies (fibrous and/or laminar) were selected as model clays. Sepiolite from Vicálvaro is an almost pure fibrous sample, Bentopharm presents a high amount of laminar particles and palygorskite from Turón is made up of similar percentages of laminar and fibrous particles. The disperse systems were made up using a rotor-stator mixer working at two different mixing rates (1000 and 8000 rpm), for periods of 1 and 10 min. Filtration measurements were taken and the corresponding filtration curves obtained. Finally, the desorptivity (S) of the filtration cakes was calculated and correlated to the textural characteristics of the materials, the solid fraction and mixing conditions. Filtration behaviour of the dispersions depended on all three of these factors. Laminar dispersions presented lower S values than fibrous dispersions. In the 2% w/v dispersions the bridging forces between particles did not permit formation of an interconnected network as in 10% w/v dispersions and, consequently, filtration times increased with the solid fraction (i.e. S values decreased). Regarding stability to pH changes, the results showed that filtration behaviour was highly sensitive to basic pH in the fibrous clay dispersions and almost insensitive in the laminar clay dispersions.

Nutrient gradients in a granular activated carbon biofilter drives bacterial community organization and dynamics.

PubMed

Boon, Nico; Pycke, Benny F G; Marzorati, Massimo; Hammes, Frederik

2011-12-01

The quality of drinking water is ensured by hygienic barriers and filtration steps, such as ozonation and granular activated carbon (GAC) filtration. Apart from adsorption, GAC filtration involves microbial processes that remove biodegradable organic carbon from the ozonated ground or surface water and ensures biological stability of the treated water. In this study, microbial community dynamics in were monitored during the start-up and maturation of an undisturbed pilot-scale GAC filter at 4 depths (10, 45, 80 and 115 cm) over a period of 6 months. New ecological tools, based on 16S rRNA gene-DGGE, were correlated to filter performance and microbial activity and showed that the microbial gradients developing in the filter was of importance. At 10 cm from the top, receiving the freshly ozonated water with the highest concentration of nutrients, the microbial community dynamics were minimal and the species richness remained low. However, the GAC samples at 80-115 cm showed a 2-3 times higher species richness than the 10-45 cm samples. The highest biomass densities were observed at 45-80 cm, which corresponded with maximum removal of dissolved and assimilable organic carbon. Furthermore, the start-up period was clearly distinguishable using the Lorenz analysis, as after 80 days, the microbial community shifted to an apparent steady-state condition with increased evenness. This study showed that GAC biofilter performance is not necessarily correlated to biomass concentration, but rather that an elevated functionality can be the result of increased microbial community richness, evenness and dynamics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Impact of Sofosbuvir-Based Regimens for the Treatment of Hepatitis C After Liver Transplant on Renal Function: Results of a Canadian National Retrospective Study.

PubMed

Faisal, Nabiha; Bilodeau, Marc; Aljudaibi, Bandar; Hirch, Geri; Yoshida, Eric M; Hussaini, Trana; Ghali, Maged P; Congly, Stephen E; Ma, Mang M; Lilly, Leslie B

2018-04-04

We assessed the impact of sofosbuvir-based regimens on renal function in liver transplant recipients with recurrent hepatitis C virus and the role of renal function on the efficacy and safety of these regimens. In an expanded pan-Canadian cohort, 180 liver transplant recipients were treated with sofosbuvir-based regimens for hepatitis C virus recurrence from January 2014 to May 2015. Mean age was 58 ± 6.85 years, and 50% had F3/4 fibrosis. Patients were stratified into 4 groups based on baseline estimated glomerular filtration rate (calculated by the Modification of Diet in Renal Disease formula): < 30, 30 to 45, 46 to 60, and > 60 mL/min/173 m2. The primary outcome was posttreatment changes in renal function from baseline. Secondary outcomes included sustained virologic response at 12 weeks posttreatment and anemia-related and serious adverse events. Posttreatment renal function was improved in most patients (58%). Renal function declined in 22% of patients, which was more marked in those with estimated glomerular filtration rate < 30 mL/min/173 m2, advanced cirrhosis (P = .05), and aggressive hepatitis C virus/fibrosing cholestatic hepatitis (P < .05). High rates (80%-88%) of sustained virologic response at 12 weeks posttreatment were seen across all renal function strata. Cirrhotic patients with glomerular filtration rates < 30 mL/min/173 m2 had sustained virologic response rates at 12 weeks posttreatment comparable to the overall patient group. Rates of anemia-related adverse events and transfusion requirements increased across decreasing estimated glomerular filtration rate groups, with notably more occurrences with ribavirin-based regimens. Sofosbuvir-based regimens improved overall renal function in liver transplant recipients, with sustained virologic response, suggesting an association of subclinical hepatitis C virus-related renal disease. Sustained virologic response rates at 12 weeks posttreatment (80%-88%) were comparable regardless of baseline renal function but lower in cirrhosis.

Growth of bacterial phytopathogens in animal manures.

PubMed

Sledz, Wojciech; Zoledowska, Sabina; Motyka, Agata; Kadziński, Leszek; Banecki, Bogdan

2017-01-01

Animal manures are routinely applied to agricultural lands to improve crop yield, but the possibility to spread bacterial phytopathogens through field fertilization has not been considered yet. We monitored 49 cattle, horse, swine, sheep or chicken manure samples collected in 14 Polish voivodeships for the most important plant pathogenic bacteria - Ralstonia solanacearum (Rsol), Xanthomonas campestris pv. campestris (Xcc), Pectobacterium carotovorum subsp. carotovorum (Pcc), Pectobacterium atrosepticum (Pba), Erwinia amylovora (Eam), Clavibacter michiganensis subsp. sepedonicus (Cms) and Dickeya sp. (Dsp). All of the tested animal fertilizers were free of these pathogens. Subsequently, the growth dynamics of Pba, Pcc, Rsol, and Xcc in cattle, horse, swine, sheep and chicken manures sterilized either by autoclaving or filtration was evaluated. The investigated phytopathogens did not exhibit any growth in the poultry manure. However, the manure filtrates originating from other animals were suitable for microbial growth, which resulted in the optical density change of 0.03-0.22 reached within 26 h (48 h Rsol, 120 h Xcc), depending on bacterial species and the manure source. Pcc and Pba multiplied most efficiently in the cattle manure filtrate. These bacteria grew faster than Rsol and Xcc in all the tested manure samples, both the filtrates and the autoclaved semi-solid ones. Though the growth dynamics of investigated strains in different animal fertilizers was unequal, all of the tested bacterial plant pathogens were proven to use cattle, horse, swine and sheep manures as the sources of nutrients. These findings may contribute to further research on the alternative routes of spread of bacterial phytopathogens, especially because of the fact that the control of pectionolytic bacteria is only based on preventive methods.

[The aspiratory resistance and filtration penetration of N95 filtering-facepiece respirators used widely in China].

PubMed

Wang, Xinyan; Shi, Tingming; Lu, Wei; Qin, Shaoxian; Liu, Yuewei; Tao, Ying; Zhang, Hongge; Chen, Weihong

2015-01-01

The objective of this study was to investigate the aspiratory resistance, filtration penetration and their influence factors of N95 filtering-facepiece respirators used widely in China. The total of 6 brands and 21 models of N95 filtering-facepiece respirators which are certified and big sales on the market. The aspiratory resistance and filtration efficiency filter penetration were measured while air pump ran from 10 L/min to 100 L/min using differential pressure gauge and the PortaCount, respectively. The filtration penetrations for 2 of the 21 models were lower than 95%, and the qualified rate for all models was 90.47%. The filtration penetrations gradually decreased when ventilation flow of air pump increased. The negative correlation was observed between filtration penetration and ventilation flow (r(2) = 0.711, P < 0.05). The resistances of all 21 models of N95 respirators met the requirements of the national standard. The aspiratory resistance started to elevate with the increasing of ventilation flow, and a positive correlation between both (r(2) = 0.878, P < 0.05). Significant differences of filtration penetration and aspiratory resistance were observed among between different brands (P < 0.05) although no differences of filtration penetration existed among different models of one brand (P > 0.05). But the differences of the aspiratory resistance among different models of one brand were statistically significant (P < 0.05). The aspiratory resistances of all N95 filtering-facepiece respirators used in this study met the requirements of the national standard. And the qualified ratio of filtration penetration of all models was higher than 90%. The influencing factors of aspiratory resistance included materials, size and ventilation flow. And influencing factors for filtration penetration were materials and ventilation flow.

Further evaluation of the NWF filter for the purification of Plasmodium vivax-infected erythrocytes.

PubMed

Li, Jiangyan; Tao, Zhiyong; Li, Qian; Brashear, Awtum; Wang, Ying; Xia, Hui; Fang, Qiang; Cui, Liwang

2017-05-17

Isolation of Plasmodium-infected red blood cells (iRBCs) from clinical blood samples is often required for experiments, such as ex vivo drug assays, in vitro invasion assays and genome sequencing. Current methods for removing white blood cells (WBCs) from malaria-infected blood are time-consuming or costly. A prototype non-woven fabric (NWF) filter was developed for the purification of iRBCs, which showed great efficiency for removing WBCs in a pilot study. Previous work was performed with prototype filters optimized for processing 5-10 mL of blood. With the commercialization of the filters, this study aims to evaluate the efficiency and suitability of the commercial NWF filter for the purification of Plasmodium vivax-infected RBCs in smaller volumes of blood and to compare its performance with that of Plasmodipur ® filters. Forty-three clinical P. vivax blood samples taken from symptomatic patients attending malaria clinics at the China-Myanmar border were processed using the NWF filters in a nearby field laboratory. The numbers of WBCs and iRBCs and morphology of P. vivax parasites in the blood samples before and after NWF filtration were compared. The viability of P. vivax parasites after filtration from 27 blood samples was examined by in vitro short-term culture. In addition, the effectiveness of the NWF filter for removing WBCs was compared with that of the Plasmodipur ® filter in six P. vivax blood samples. Filtration of 1-2 mL of P. vivax-infected blood with the NWF filter removed 99.68% WBCs. The densities of total iRBCs, ring and trophozoite stages before and after filtration were not significantly different (P > 0.05). However, the recovery rates of schizont- and gametocyte-infected RBCs, which were minor parasite stages in the clinical samples, were relatively low. After filtration, the P. vivax parasites did not show apparent morphological changes. Culture of 27 P. vivax-infected blood samples after filtration showed that parasites successfully matured into the schizont stage. The WBC removal rates and iRBC recovery rates were not significantly different between the NWF and Plasmodipur ® filters (P > 0.05). When tested with 1-2 mL of P. vivax-infected blood, the NWF filter could effectively remove WBCs and the recovery rates for ring- and trophozoite-iRBCs were high. P. vivax parasites after filtration could be successfully cultured in vitro to reach maturity. The performance of the NWF and Plasmodipur ® filters for removing WBCs and recovering iRBCs was comparable.

Filtration by eyelashes

NASA Astrophysics Data System (ADS)

Vistarakula, Krishna; Bergin, Mike; Hu, David

2010-11-01

Nearly every mammalian and avian eye is rimmed with lashes. We investigate experimentally the ability of lashes to reduce airborne particle deposition in the eye. We hypothesize that there is an optimum eyelash length that maximizes both filtration ability and extent of peripheral vision. This hypothesis is tested using a dual approach. Using preserved heads from 36 species of animals at the American Museum of Natural History, we determine the relationship between eye size and eyelash geometry (length and spacing). We test the filtration efficacy of these geometries by deploying outdoor manikins and measuring particle deposition rate as a function of eyelash length.

Determination of glomerular function in advanced renal failure.

PubMed Central

Manz, F; Alatas, H; Kochen, W; Lutz, P; Rebien, W; Schärer, K

1977-01-01

In 15 children with advanced chronic renal failure, glomerular filtration rate was determined by different methods. Inulin clearance correlated well with the mean of creatinine and urea clearance, and also with 51-chromium edetic acid (EDTA) clearance measured over 24 hours. The absolute values of creatinine clearance and of 51Cr-EDTA clearance measured up to 8 hours were higher than inulin clearance. In advanced renal failure both the 51Cr-EDTA clearance measured over 24 hours, and the mean of creatinine and urea clearance, provide acceptable estimates of true glomerular filtration rate. PMID:411426

Serum uric acid concentration is associated with early changes of glomerular filtration rate in patients with diabetes type 1 without increased albumin excretion.

PubMed

Spaleniak, Sebastian; Korzeniewska-Dyl, Irmina; Moczulski, Dariusz

2014-10-01

The early loss of renal function in patients with type 1 diabetes may begin before proteinuria. Only 30% of patients with diabetes manifest overt proteinuria. According to the previous studies, increased urinary albumin excretion, which is considered a classic marker of progression of diabetic kidney disease, can regress to normal urine albumin excretion. The current studies conducted in patients with type 1 diabetes without increased urine albumin excretion showed that the uric acid concentration was an independent factor for the development of diabetic kidney disease. The aim of study was to assess the impact of uric acid concentration and to identify risk factors of the early glomerular filtration loss in patients with type 1 diabetes and normal urinary albumin excretion. 147 patients (61 women and 86 men) with type 1 diabetes without increased urine albumin excretion were analysed. GFR (gromerular filtration rate) was estimated based on the serum cystatin C concentration. Centile charts were used to determine the variation of uric acid concentration depending on GFR and gender. The mean value of the filtration rate for the study group was 117 ml/min/m2. The uric acid level above 90th percentile in relation to GFR was diagnosed in 8.2% of women and 0% of men, between 90th and 50th percentile in 44.3 % of women and 5.8% of men and below 50th percentile in 47.5% of women and 94.2% of men. Contrary to men in women higher serum acid concentration was strongly associated with higher glomerular filtration rate. Hyperfiltraion was diagnosed in 15 of women and 19 of men. The high normal uric acid concentration in women with type 1 diabetes might play a crucial role in development of hyperfiltration.

Renal Blood Flow, Glomerular Filtration Rate, and Renal Oxygenation in Early Clinical Septic Shock.

PubMed

Skytte Larsson, Jenny; Krumbholz, Vitus; Enskog, Anders; Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2018-06-01

Data on renal hemodynamics, function, and oxygenation in early clinical septic shock are lacking. We therefore measured renal blood flow, glomerular filtration rate, renal oxygen consumption, and oxygenation in patients with early septic shock. Prospective comparative study. General and cardiothoracic ICUs. Patients with norepinephrine-dependent early septic shock (n = 8) were studied within 24 hours after arrival in the ICU and compared with postcardiac surgery patients without acute kidney injury (comparator group, n = 58). None. Data on systemic hemodynamics and renal variables were obtained during two 30-minute periods. Renal blood flow was measured by the infusion clearance of para-aminohippuric acid, corrected for renal extraction of para-aminohippuric acid. Renal filtration fraction was measured by renal extraction of chromium-51 labeled EDTA. Renal oxygenation was estimated from renal oxygen extraction. Renal oxygen delivery (-24%; p = 0.037) and the renal blood flow-to-cardiac index ratio (-21%; p = 0.018) were lower, renal vascular resistance was higher (26%; p = 0.027), whereas renal blood flow tended to be lower (-19%; p = 0.068) in the septic group. Glomerular filtration rate (-32%; p = 0.006) and renal sodium reabsorption (-29%; p = 0.014) were both lower in the septic group. Neither renal filtration fraction nor renal oxygen consumption differed significantly between groups. Renal oxygen extraction was significantly higher in the septic group (28%; p = 0.022). In the septic group, markers of tubular injury were elevated. In early clinical septic shock, renal function was lower, which was accompanied by renal vasoconstriction, a lower renal oxygen delivery, impaired renal oxygenation, and tubular sodium reabsorption at a high oxygen cost compared with controls.

Novel Optical Diagnostic Techniques for Studying Particle Deposition Upon Large Cylinders in a Sheared Suspension

NASA Technical Reports Server (NTRS)

Yoda, M.; Bailey, B. C.

2000-01-01

On a twelve-month voyage to Mars, one astronaut will require at least two tons of potable water and two tons of pure oxygen. Efficient, reliable fluid reclamation is therefore necessary for manned space exploration. Space habitats require a compact, flexible, and robust apparatus capable of solid-fluid mechanical separation over a wide range of fluid and particle densities and particle sizes. In space, centrifugal filtration, where particles suspended in fluid are captured by rotating fixed-fiber mat filters, is a logical candidate for mechanical separation. Non-colloidal particles are deposited on the fibers due to inertial impaction or direct interception. Since rotation rates are easily adjustable, inertial effects are the most practical way to control separation rates for a wide variety of multiphase mixtures in variable gravity environments. Understanding how fluid inertia and differential fluid-particle inertia, characterized by the Reynolds and Stokes numbers, respectively, affect deposition is critical in optimizing filtration in a microgravity environment. This work will develop non-intrusive optical diagnostic techniques for directly visualizing where and when non-colloidal particles deposit upon, or contact, solid surfaces: 'particle proximity sensors'. To model particle deposition upon a single filter fiber, these sensors will be used in ground-based experiments to study particle dynamics as in the vicinity of a large (compared with the particles) cylinder in a simply sheared (i.e., linearly-varying, zero-mean velocity profile) neutrally-buoyant, refractive-index matched solid-liquid suspension.

Environmental tobacco smoke particles in multizone indoor environments

NASA Astrophysics Data System (ADS)

Miller, S. L.; Nazaroff, W. W.

Environmental tobacco smoke (ETS) is a major source of human exposure to airborne particles. To better understand the factors that affect exposure, and to investigate the potential effectiveness of technical control measures, a series of experiments was conducted in a two-room test facility. Particle concentrations, size distributions, and airflow rates were measured during and after combustion of a cigarette. Experiments were varied to obtain information about the effects on exposure of smoker segregation, ventilation modification, and air filtration. The experimental data were used to test the performance of an analytical model of the two-zone environment and a numerical multizone aerosol dynamics model. A respiratory tract particle deposition model was also applied to the results to estimate the mass of ETS particles that would be deposited in the lungs of a nonsmoker exposed in either the smoking or nonsmoking room. Comparisons between the experimental data and model predictions showed good agreement. For time-averaged particle mass concentration, the average bias between model and experiments was less than 10%. The average absolute error was typically 35%, probably because of variability in particle emission rates from cigarettes. For the conditions tested, the use of a portable air filtration unit yielded 65-90% reductions in predicted lung deposition relative to the baseline scenario. The use of exhaust ventilation in the smoking room reduced predicted lung deposition in the nonsmoking room by more than 80%, as did segregating the smoker from nonsmokers with a closed door.

Technical note: Use of a simplified equation for estimating glomerular filtration rate in beef cattle.

PubMed

Murayama, I; Miyano, A; Sasaki, Y; Hirata, T; Ichijo, T; Satoh, H; Sato, S; Furuhama, K

2013-11-01

This study was performed to clarify whether a formula (Holstein equation) based on a single blood sample and the isotonic, nonionic, iodine contrast medium iodixanol in Holstein dairy cows can apply to the estimation of glomerular filtration rate (GFR) for beef cattle. To verify the application of iodixanol in beef cattle, instead of the standard tracer inulin, both agents were coadministered as a bolus intravenous injection to identical animals at doses of 10 mg of I/kg of BW and 30 mg/kg. Blood was collected 30, 60, 90, and 120 min after the injection, and the GFR was determined by the conventional multisample strategies. The GFR values from iodixanol were well consistent with those from inulin, and no effects of BW, age, or parity on GFR estimates were noted. However, the GFR in cattle weighing less than 300 kg, aged<1 yr old, largely fluctuated, presumably due to the rapid ruminal growth and dynamic changes in renal function at young adult ages. Using clinically healthy cattle and those with renal failure, the GFR values estimated from the Holstein equation were in good agreement with those by the multisample method using iodixanol (r=0.89, P=0.01). The results indicate that the simplified Holstein equation using iodixanol can be used for estimating the GFR of beef cattle in the same dose regimen as Holstein dairy cows, and provides a practical and ethical alternative.

Detection of relationships between SUDOSCAN with estimated glomerular filtration rate (eGFR) in Chinese patients with type 2 diabetes.

PubMed

Mao, Fei; Zhu, Xiaoming; Lu, Bin; Li, Yiming

2018-04-01

SUDOSCAN (Impeto Medical, Paris, France) has been proved to be a new and non-invasive method in detecting renal dysfunction in type 2 diabetes mellitus (T2DM) patients. In this study, we sought to compare the result of diabetic kidney dysfunction score (DKD-score) of SUDOSCAN with estimated glomerular filtration rate (eGFR) by using quantile regression analysis, which was completely different from previous studies. A total number of 223 Chinese T2DM patients were enrolled in the study. SUDOSCAN, renal function test (including blood urea nitrogen, creatinine and uric acid) and 99 mTc-diethylenetriamine pentaacetic acid ( 99 mTc-DTPA) renal dynamic imaging were performed in all T2DM patients. DKD-score of SUDOSCAN was compared with eGFR detected by 99 mTc-DTPA renal dynamic imaging through quantile regression analysis. Its validation and utility was further determined through bias and precision test. The quantile regression analysis demonstrated the relationship with eGFR was inverse and significant for almost all percentiles of DKD-score. The coefficients decreased as the percentile of DKD-score increased. And in validation data set, both the bias and precision were increased with the eGFR (median difference, -21.2 ml/min/1.73 m 2 for all individuals vs. -4.6 ml/min/1.73 m 2 for eGFR between 0 and 59 ml/min/1.73 m 2 ; interquartile range [IQR] for the difference, -25.4 ml/min/1.73 m 2 vs. -14.7 ml/min/1.73 m 2 ). The eGFR category misclassification rate were 10% in eGFR 0-59 ml/min/1.73 m 2 group, 57.3% in 60-90 group, and 87.2% in eGFR > 90 ml/min/1.73 m 2 group. DKD-score of SUDOSCAN could be used to detect renal dysfunction in T2DM patients. A higher prognostic value of DKD-score was detected when eGFR level was lower. Copyright © 2018 Elsevier B.V. All rights reserved.

Feasibility of granular bed filtration of an aerosol of ultrafine metallic particles including a pressure drop regeneration system.

PubMed

Bémer, D; Wingert, L; Morele, Y; Subra, I

2015-09-01

A process for filtering an aerosol of ultrafine metallic particles (UFP) has been designed and tested, based on the principle of a multistage granular bed. The filtration system comprised a succession of granular beds of varying thickness composed of glass beads of different diameters. This system allows the pressure drop to be regenerated during filtration ("on-line" mode) using a vibrating probe. Tests monitoring the pressure drop were conducted on a "10-L/min" low airflow rate device and on a "100-m(3)/hr" prototype. Granular bed unclogging is automated on the latter. The cyclic operation and filtration performances are similar to that of filter medium-based industrial dust collectors. Filtration of ultrafine metallic particles generated by different industrial processes such as arc welding, metal cutting, or spraying constitutes a difficult problem due to the high filter clogging properties of these particles and to the high temperatures generally encountered. Granular beds represent an advantageous means of filtering these aerosols with difficult properties.

Evaluation of Filtration and UV Disinfection for Inactivation of ...

EPA Pesticide Factsheets

This study evaluated filtration and disinfection processes for removal and inactivation of pathogens in non-community water systems (NCWS) in two surface water supplies. Pretreatment systems included 1) pressure sand filtration, and 2) granular activated carbon adsorption, and 3) cartridge filtration. Two types of low-pressure UV systems were evaluated with and without pretreatment systems. The presentation will provide results for removal of particles and inactivation of MS2 bacteriophage (a viral surrogate) on two surface waters in northeastern Minnesota. Several studies, including a recent study conducted by Minnesota Department of Health (MDH), show that viruses occur in groundwater at a higher rate than expected. Based on preliminary results in Minnesota, virus occurrence appears to be correlated with recharge events such as heavy rainfall and snowmelt. These recharge events are predicted to become more extreme due to climate change impacts. Filtration, ultraviolet (UV) disinfection, and chlorination, can provide a multi-barrier approach for removal or inactivation of pathogens and DBP precursors in both groundwater and surface water systems.

Experimental investigation of the effect of inlet particle properties on the capture efficiency in an exhaust particulate filter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viswanathan, Sandeep; Rothamer, David; Zelenyuk, Alla

The impact of inlet particle properties on the filtration performance of clean and particulate matter (PM) laden cordierite filter samples was evaluated using PM generated by a spark-ignition direct-injection (SIDI) engine fuelled with tier II EEE certification gasoline. Prior to the filtration experiments, a scanning mobility particle spectrometer (SMPS) was used to measure the electrical-mobility based particle size distribution (PSD) in the SIDI exhaust from distinct engine operating conditions. An advanced aerosol characterization system that comprised of a centrifugal particle mass analyser (CPMA), a differential mobility analyser (DMA), and a single particle mass spectrometer (SPLAT II) was used to obtainmore » additional information on the SIDI particulate, including particle composition, mass, and dynamic shape factors (DSFs) in the transition () and free-molecular () flow regimes. During the filtration experiments, real-time measurements of PSDs upstream and downstream of the filter sample were used to estimate the filtration performance and the total trapped mass within the filter using an integrated particle size distribution method. The filter loading process was paused multiple times to evaluate the filtration performance in the partially loaded state. The change in vacuum aerodynamic diameter () distribution of mass-selected particles was examined for flow through the filter to identify whether preferential capture of particles of certain shapes occurred in the filter. The filter was also probed using different inlet PSDs to understand their impact on particle capture within the filter sample. Results from the filtration experiment suggest that pausing the filter loading process and subsequently performing the filter probing experiments did not impact the overall evolution of filtration performance. Within the present distribution of particle sizes, filter efficiency was independent of particle shape potentially due to the diffusion-dominant filtration process. Particle mobility diameter and trapped mass within the filter appeared to be the dominant parameters that impacted filter performance.« less

Biofiltration of airborne VOCs with green wall systems-Microbial and chemical dynamics.

PubMed

Mikkonen, A; Li, T; Vesala, M; Saarenheimo, J; Ahonen, V; Kärenlampi, S; Blande, J D; Tiirola, M; Tervahauta, A

2018-05-06

Botanical air filtration is a promising technology for reducing indoor air contaminants, but the underlying mechanisms need better understanding. Here, we made a set of chamber fumigation experiments of up to 16 weeks of duration, to study the filtration efficiencies for seven volatile organic compounds (VOCs; decane, toluene, 2-ethylhexanol, α-pinene, octane, benzene, and xylene) and to monitor microbial dynamics in simulated green wall systems. Biofiltration functioned on sub-ppm VOC levels without concentration-dependence. Airflow through the growth medium was needed for efficient removal of chemically diverse VOCs, and the use of optimized commercial growth medium further improved the efficiency compared with soil and Leca granules. Experimental green wall simulations using these components were immediately effective, indicating that initial VOC removal was largely abiotic. Golden pothos plants had a small additional positive impact on VOC filtration and bacterial diversity in the green wall system. Proteobacteria dominated the microbiota of rhizosphere and irrigation water. Airborne VOCs shaped the microbial communities, enriching potential VOC-utilizing bacteria (especially Nevskiaceae and Patulibacteraceae) in the irrigation water, where much of the VOC degradation capacity of the biofiltration systems resided. These results clearly show the benefits of active air circulation and optimized growth media in modern green wall systems. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Water research program final report, March 15, 1970 to October 31, 1972. Separations processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minturn, R. E.

A summary article on separation by filtration is reprinted, and research is reported in the following areas: dynamic membranes, cast film membranes, concentration polarization, economic analysis; and enhanced heat transfer. (DHM)

Global sensitivity analysis of a filtration model for submerged anaerobic membrane bioreactors (AnMBR).

PubMed

Robles, A; Ruano, M V; Ribes, J; Seco, A; Ferrer, J

2014-04-01

The results of a global sensitivity analysis of a filtration model for submerged anaerobic MBRs (AnMBRs) are assessed in this paper. This study aimed to (1) identify the less- (or non-) influential factors of the model in order to facilitate model calibration and (2) validate the modelling approach (i.e. to determine the need for each of the proposed factors to be included in the model). The sensitivity analysis was conducted using a revised version of the Morris screening method. The dynamic simulations were conducted using long-term data obtained from an AnMBR plant fitted with industrial-scale hollow-fibre membranes. Of the 14 factors in the model, six were identified as influential, i.e. those calibrated using off-line protocols. A dynamic calibration (based on optimisation algorithms) of these influential factors was conducted. The resulting estimated model factors accurately predicted membrane performance. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fish mouths as engineering structures for vortical cross-step filtration

NASA Astrophysics Data System (ADS)

Sanderson, S. Laurie; Roberts, Erin; Lineburg, Jillian; Brooks, Hannah

2016-03-01

Suspension-feeding fishes such as goldfish and whale sharks retain prey without clogging their oral filters, whereas clogging is a major expense in industrial crossflow filtration of beer, dairy foods and biotechnology products. Fishes' abilities to retain particles that are smaller than the pore size of the gill-raker filter, including extraction of particles despite large holes in the filter, also remain unexplained. Here we show that unexplored combinations of engineering structures (backward-facing steps forming d-type ribs on the porous surface of a cone) cause fluid dynamic phenomena distinct from current biological and industrial filter operations. This vortical cross-step filtration model prevents clogging and explains the transport of tiny concentrated particles to the oesophagus using a hydrodynamic tongue. Mass transfer caused by vortices along d-type ribs in crossflow is applicable to filter-feeding duck beak lamellae and whale baleen plates, as well as the fluid mechanics of ventilation at fish gill filaments.

Efficacy of different types of self-expandable stents in carotid artery stenting for carotid bifurcation stenosis.

PubMed

Liu, Ya-min; Qin, Hao; Zhang, Bo; Wang, Yu-jing; Feng, Jun; Wu, Xiang

2016-02-01

Both open and closed loop self-expandable stents were used in carotid artery stenting (CAS) for carotid bifurcation stenosis. We sought to compare the efficacy of two types of stents in CAS. The data of 212 patients treated with CAS (42 and 170 cases implanted with closed and open loop stents, respectively) for carotid bifurcation stenosis and distal filtration protection devices were retrospectively analyzed. Between closed and open loop stents, there were no significant differences in hospitalization duration, NIHSS score before and after the treatment, stenosis at 12th month, and cumulative incidence of primary endpoint events within 30 days or from the 31st day to the 12th month; while there were significant differences in hemodynamic changes and rate of difficulty in recycling distal filtration protection devices. Use of open vs. closed loop stents for carotid bifurcation stenosis seems to be associated with similar incidence of complications, except for greater rate of hemodynamic changes and lower rate of difficulty in recycling the distal filtration protection devices.

Relationship between oxygen concentration, respiration and filtration rate in blue mussel Mytilus edulis

NASA Astrophysics Data System (ADS)

Tang, Baojun; Riisgård, Hans Ulrik

2018-03-01

The large water-pumping and particle-capturing gills of the filter-feeding blue mussel Mytilus edulis are oversized for respiratory purposes. Consequently, the oxygen uptake rate of the mussel has been suggested to be rather insensitive to decreasing oxygen concentrations in the ambient water, since the diffusion rate of oxygen from water flowing through the mussel determines oxygen uptake. We tested this hypothesis by measuring the oxygen uptake in mussels exposed to various oxygen concentrations. These concentrations were established via N2-bubbling of the water in a respiration chamber with mussels fed algal cells to stimulate fully opening of the valves. It was found that mussels exposed to oxygen concentrations decreasing from 9 to 2 mg O2/L resulted in a slow but significant reduction in the respiration rate, while the filtration rate remained high and constant. Thus, a decrease of oxygen concentration by 78% only resulted in a 25% decrease in respiration rate. However, at oxygen concentrations below 2 mg O2/L M. edulis responded by gradually closing its valves, resulting in a rapid decrease of filtration rate, concurrent with a rapid reduction of respiration rate. These observations indicated that M. edulis is no longer able to maintain its normal aerobic metabolism at oxygen concentration below 2 mg O2/L, and there seems to be an energy-saving mechanism in bivalve molluscs to strongly reduce their activity when exposed to low oxygen conditions.

A comparative study of Sephadex, glass wool and Percoll separation techniques on sperm quality and IVF results for cryopreserved bovine semen.

PubMed

Lee, Hae-Lee; Kim, Sue-Hee; Ji, Dong-Beom; Kim, Yong-Jun

2009-09-01

The aim of this study was to compare the effects of spermatozoa separation techniques on sperm quality and in-vitro fertilization (IVF) results for cryopreserved bovine semen. Sephadex, glass wool and Percoll gradient separation techniques were used for sperm separation and sperm motility, morphology and membrane integrity were evaluated before and after separation. Also, cleavage and blastocyst developmental rate were investigated after IVF with sperm recovered by each separation technique. The motility of samples obtained by the three separation techniques were greater compared to the control samples (p < 0.05). The percentage of spermatozoa with intact plasma-membrane integrity, identified by 6-carboxyfluoresceindiacetate/ propidium iodide fluorescent staining and the hypo-osmotic swelling test, was highest in the glass wool filtration samples (p < 0.05). The cleavage and blastocyst rate of total oocytes produced from glass wool filtration samples were also higher than the control and Sephadex filtration samples (p < 0.05), but were not significantly different from Percoll separation samples. However, a significantly greater number of cleaved embryos produced by glass wool filtration developed to blastocyst stage than those produced by Percoll separation (p < 0.05). These results indicate that spermatozoa with good quality can be achieved by these three separation techniques and can be used for bovine IVF. In particular, it suggests that glass wool filtration would be the most effective method of the three for improving sperm quality and embryo production for cryopreserved bovine spermatozoa.

Advanced Filter Technology For Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Castillon, Erick

2015-01-01

The Scrubber System focuses on using HEPA filters and carbon filtration to purify the exhaust of a Nuclear Thermal Propulsion engine of its aerosols and radioactive particles; however, new technology may lend itself to alternate filtration options, which may lead to reduction in cost while at the same time have the same filtering, if not greater, filtering capabilities, as its predecessors. Extensive research on various types of filtration methods was conducted with only four showing real promise: ionization, cyclonic separation, classic filtration, and host molecules. With the four methods defined, more research was needed to find the devices suitable for each method. Each filtration option was matched with a device: cyclonic separators for the method of the same name, electrostatic separators for ionization, HEGA filters, and carcerands for the host molecule method. Through many hours of research, the best alternative for aerosol filtration was determined to be the electrostatic precipitator because of its high durability against flow rate and its ability to cleanse up to 99.99% of contaminants as small as 0.001 micron. Carcerands, which are the only alternative to filtering radioactive particles, were found to be non-existent commercially because of their status as a "work in progress" at research institutions. Nevertheless, the conclusions after the research were that HEPA filters is recommended as the best option for filtering aerosols and carbon filtration is best for filtering radioactive particles.

Comparative Recoveries of Naegleria fowleri Amoebae from Seeded River Water by Filtration and Centrifugation

PubMed Central

Pernin, P.; Pélandakis, M.; Rouby, Y.; Faure, A.; Siclet, F.

1998-01-01

Detection of pathogenic Naegleria fowleri in environmental water samples, which is necessary for the prevention of primary amoebic meningoencephalitis, generally requires concentrating the samples. Two concentration techniques, filtration and centrifugation, were used to study the recovery of N. fowleri, in vegetative or cystic form, that had been mixed with the two other thermotolerant Naegleria species, N. lovaniensis and N. australiensis. Counting of amoebae was performed by the most probable number method on 10 water replicates of 100 ml and 10 ml each. With both concentration methods, recovery was better for cysts than for trophozoites (53% ± 21% versus 5% ± 5% by filtration and 57% ± 25% versus 22% ± 5% by centrifugation). The recovery of Naegleria trophozoites by filtration was very low, and centrifugation was significantly better than filtration in recovery of Naegleria trophozoites (22% ± 5% versus 5% ± 5%; P < 0.001). For cysts, however, filtration appeared as efficient as centrifugation, with equivalent values for recovery (53% ± 21% versus 57% ± 25%; P > 0.7). Although the recovery of cysts of N. fowleri obtained by filtration (51% ± 24%) appeared higher than that by centrifugation (36% ± 23%), the difference was not significant (P > 0.1). Both concentration methods have highly variable recovery rates, making accurate quantification of low concentrations (<100/liter) of N. fowleri in the environment difficult. PMID:9501435

Herpes

MedlinePlus

... Testing Epstein-Barr Virus (EBV) Antibody Tests Erythrocyte Sedimentation Rate (ESR) Erythropoietin Estimated Glomerular Filtration Rate (eGFR) ... Available online at http://health.lifestyle.yahoo.ca/channel_section_details.asp?text_id=1364&channel_id= ...

[A computer tomography assisted method for the automatic detection of region of interest in dynamic kidney images].

PubMed

Jing, Xueping; Zheng, Xiujuan; Song, Shaoli; Liu, Kai

2017-12-01

Glomerular filtration rate (GFR), which can be estimated by Gates method with dynamic kidney single photon emission computed tomography (SPECT) imaging, is a key indicator of renal function. In this paper, an automatic computer tomography (CT)-assisted detection method of kidney region of interest (ROI) is proposed to achieve the objective and accurate GFR calculation. In this method, the CT coronal projection image and the enhanced SPECT synthetic image are firstly generated and registered together. Then, the kidney ROIs are delineated using a modified level set algorithm. Meanwhile, the background ROIs are also obtained based on the kidney ROIs. Finally, the value of GFR is calculated via Gates method. Comparing with the clinical data, the GFR values estimated by the proposed method were consistent with the clinical reports. This automatic method can improve the accuracy and stability of kidney ROI detection for GFR calculation, especially when the kidney function has been severely damaged.

Simultaneous glucose production from cellulose and fouling reduction using a magnetic responsive membrane reactor with superparamagnetic nanoparticles carrying cellulolytic enzymes.

PubMed

Gebreyohannes, Abaynesh Yihdego; Dharmjeet, Madhav; Swusten, Tom; Mertens, Matthias; Verspreet, Joran; Verbiest, Thierry; Courtin, Christophe M; Vankelecom, Ivo F J

2018-05-02

This work aimed at investigating simultaneous hydrolysis of cellulose and in-situ foulant degradation in a cellulose fed superparamagnetic biocatalytic membrane reactor (BMR SP ). In this reactor, a dynamic layer of superparamagnetic bionanocomposites with immobilized cellulolytic enzymes were reversibly immobilized on superparamagnetic polymeric membrane using an external magnetic field. The formation of a dynamic layer of bionanocomposites on the membrane helped to prevent direct membrane-foulant interaction. Due to in-situ biocatalysis, there was limited filtration resistance. Simultaneous separation of the product helped to avoid enzyme product inhibition, achieve constant reaction rate over time and 50% higher enzyme efficiency than batch reactor. Stable enzyme immobilization and the ability to keep enzyme in the system for long period helped to achieve continuous productivity at very low enzyme but high solid loading, while also reducing the extent of membrane fouling. Hence, the BMR SP paves a path for sustainable production of bioethanol from the cheaply available lignocellulose. Copyright © 2018 Elsevier Ltd. All rights reserved.

Use of Hydrogenophaga pseudoflava Penetration To Quantitatively Assess the Impact of Filtration Parameters for 0.2-Micrometer-Pore-Size Filters ▿

PubMed Central

Lee, A.; McVey, J.; Faustino, P.; Lute, S.; Sweeney, N.; Pawar, V.; Khan, M.; Brorson, K.; Hussong, D.

2010-01-01

Filters rated as having a 0.2-μm pore size (0.2-μm-rated filters) are used in laboratory and manufacturing settings for diverse applications of bacterial and particle removal from process fluids, analytical test articles, and gasses. Using Hydrogenophaga pseudoflava, a diminutive bacterium with an unusual geometry (i.e., it is very thin), we evaluated passage through 0.2-μm-rated filters and the impact of filtration process parameters and bacterial challenge density. We show that consistent H. pseudoflava passage occurs through 0.2-μm-rated filters. This is in contrast to an absence of significant passage of nutritionally challenged bacteria that are of similar size (i.e., hydrodynamic diameter) but dissimilar geometry. PMID:19966023

Limitations of analyses based on achieved blood pressure: lessons from the African American study of kidney disease and hypertension trial.

PubMed

Davis, Esa M; Appel, Lawrence J; Wang, Xuelei; Greene, Tom; Astor, Brad C; Rahman, Mahboob; Toto, Robert; Lipkowitz, Michael S; Pogue, Velvie A; Wright, Jackson T

2011-06-01

Blood pressure (BP) guidelines that set target BP levels often rely on analyses of achieved BP from hypertension treatment trials. The objective of this article was to compare the results of analyses of achieved BP to intention-to-treat analyses on renal disease progression. Participants (n=1094) in the African-American Study of Kidney Disease and Hypertension Trial were randomly assigned to either usual BP goal defined by a mean arterial pressure goal of 102 to 107 mm Hg or lower BP goal defined by a mean arterial pressure goal of ≤92 mm Hg. Median follow-up was 3.7 years. Primary outcomes were rate of decline in measured glomerular filtration rate and a composite of a decrease in glomerular filtration rate by >50% or >25 mL/min per 1.73 m(2), requirement for dialysis, transplantation, or death. Intention-to-treat analyses showed no evidence of a BP effect on either the rate of decline in glomerular filtration rate or the clinical composite outcome. In contrast, the achieved BP analyses showed that each 10-mm Hg increment in mean follow-up achieved mean arterial pressure was associated with a 0.35 mL/min per 1.73 m(2) (95% CI: 0.08 to 0.62 mL/min per 1.73 m(2); P=0.01) faster mean glomerular filtration rate decline and a 17% (95% CI: 5% to 32%; P=0.006) increased risk of the clinical composite outcome. Analyses based on achieved BP lead to markedly different inferences than traditional intention-to-treat analyses, attributed in part to confounding of achieved BP with comorbidities, disease severity, and adherence. Clinicians and policy makers should exercise caution when making treatment recommendations based on analyses relating outcomes to achieved BP.

Membrane morphology and topology for fouling control in Reverse Osmosis filtration systems

NASA Astrophysics Data System (ADS)

Ling, Bowen; Battiato, Ilenia

2017-11-01

Reverse Osmosis Membrane (ROM) filtration systems are widely utilized in waste-water recovery, seawater desalination, landfill water treatment, etc. During filtration, the system performance is dramatically affected by membrane fouling which causes a significant decrease in permeate flux as well as an increase in the energy input required to operate the system. Design and optimization of ROM filtration systems aim at reducing membrane fouling by studying the coupling between membrane structure, local flow field and foulant adsorption patterns. Yet, current studies focus exclusively on oversimplified steady-state models that ignore any dynamic coupling between fluid flow and transport through the membrane. In this work, we develop a customized solver (SUMembraneFoam) under OpenFOAM to solve the transient equations. The simulation results not only predict macroscopic quantities (e.g. permeate flux, pressure drop, etc.) but also show an excellent agreement with the fouling patterns observed in experiments. It is observed that foulant deposition is strongly controlled by the local shear stress on the membrane, and channel morphology or membrane topology can be modified to control the shear stress distribution and reduce fouling. Finally, we identify optimal regimes for design.

Polyethersulfone/polyacrylonitrile blended ultrafiltration membranes: preparation, morphology and filtration properties.

PubMed

Pasaoglu, Mehmet Emin; Guclu, Serkan; Koyuncu, Ismail

Polyethersulfone (PES)/polyacrylonitrile (PAN) membranes have been paid attention among membrane research subjects. However, very few studies are included in the literature. In our study, asymmetric ultrafiltration (UF) membranes were prepared from blends of PES/PAN with phase inversion method using water as coagulation bath. Polyvinylpyrrolidone (PVP) with Mw of 10,000 Da was used as pore former agent. N,N-dimethylformamide was used as solvent. The effects of different percentage of PVP and PES/PAN composition on morphology and water filtration properties were investigated. Membrane performances were examined using pure water and lake water filtration studies. Performances of pure water were less with the addition of PAN into the PES polymer casting solutions. However, long-term water filtration tests showed that PES/PAN blend membranes anti-fouling properties were much higher than the neat PES membranes. The contact angles of PES/PAN membranes were lower than neat PES membranes because of PAN addition in PES polymer casting solutions. Furthermore, it was found that PES/PAN blend UF membranes' dynamic mechanical analysis properties in terms of Young's modules were less than neat PES membrane because of decreasing amount of PES polymer.

Isolation of circulating tumor cells from pancreatic cancer by automated filtration

PubMed Central

Brychta, Nora; Drosch, Michael; Driemel, Christiane; Fischer, Johannes C.; Neves, Rui P.; Esposito, Irene; Knoefel, Wolfram; Möhlendick, Birte; Hille, Claudia; Stresemann, Antje; Krahn, Thomas; Kassack, Matthias U.; Stoecklein, Nikolas H.; von Ahsen, Oliver

2017-01-01

It is now widely recognized that the isolation of circulating tumor cells based on cell surface markers might be hindered by variability in their protein expression. Especially in pancreatic cancer, isolation based only on EpCAM expression has produced very diverse results. Methods that are independent of surface markers and therefore independent of phenotypical changes in the circulating cells might increase CTC recovery also in pancreatic cancer. We compared an EpCAM-dependent (IsoFlux) and a size-dependent (automated Siemens Healthineers filtration device) isolation method for the enrichment of pancreatic cancer CTCs. The recovery rate of the filtration based approach is dramatically superior to the EpCAM-dependent approach especially for cells with low EpCAM-expression (filtration: 52%, EpCAM-dependent: 1%). As storage and shipment of clinical samples is important for centralized analyses, we also evaluated the use of frozen diagnostic leukapheresis (DLA) as source for isolating CTCs and subsequent genetic analysis such as KRAS mutation detection analysis. Using frozen DLA samples of pancreatic cancer patients we detected CTCs in 42% of the samples by automated filtration. PMID:29156783

Isolation of circulating tumor cells from pancreatic cancer by automated filtration.

PubMed

Brychta, Nora; Drosch, Michael; Driemel, Christiane; Fischer, Johannes C; Neves, Rui P; Esposito, Irene; Knoefel, Wolfram; Möhlendick, Birte; Hille, Claudia; Stresemann, Antje; Krahn, Thomas; Kassack, Matthias U; Stoecklein, Nikolas H; von Ahsen, Oliver

2017-10-17

It is now widely recognized that the isolation of circulating tumor cells based on cell surface markers might be hindered by variability in their protein expression. Especially in pancreatic cancer, isolation based only on EpCAM expression has produced very diverse results. Methods that are independent of surface markers and therefore independent of phenotypical changes in the circulating cells might increase CTC recovery also in pancreatic cancer. We compared an EpCAM-dependent (IsoFlux) and a size-dependent (automated Siemens Healthineers filtration device) isolation method for the enrichment of pancreatic cancer CTCs. The recovery rate of the filtration based approach is dramatically superior to the EpCAM-dependent approach especially for cells with low EpCAM-expression (filtration: 52%, EpCAM-dependent: 1%). As storage and shipment of clinical samples is important for centralized analyses, we also evaluated the use of frozen diagnostic leukapheresis (DLA) as source for isolating CTCs and subsequent genetic analysis such as KRAS mutation detection analysis. Using frozen DLA samples of pancreatic cancer patients we detected CTCs in 42% of the samples by automated filtration.

Microfluidic colloid filtration

PubMed Central

Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

2016-01-01

Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

Separation and Concentration without Clogging Using a High-Throughput Tunable Filter

NASA Astrophysics Data System (ADS)

Mossige, E. J.; Jensen, A.; Mielnik, M. M.

2018-05-01

We present a detailed experimental study of a hydrodynamic filtration microchip and show how chip performance can be tuned and clogging avoided by adjusting the flow rates. We demonstrate concentration and separation of microspheres at throughputs as high as 29 ml /min and with 96% pureness. Results of streakline visualizations show that the thickness of a tunable filtration layer dictates the cutoff size and that two different concentration mechanisms exist. Particles larger than pores are concentrated by low-velocity rolling over the filtration pillars, while particles smaller than pores are concentrated by lateral drift across the filtration layer. Results of microscopic particle image velocimetry and particle-tracking velocimetry show that the degree of lateral migration can be quantified by the slip velocity between the particle and the surrounding fluid. Finally, by utilizing differences in inertia and separation mode, we demonstrate size-based separation of particles in a mixture.

EX-PRESS Glaucoma Filtration Device: efficacy, safety, and predictability

PubMed Central

Chan, Jessica E; Netland, Peter A

2015-01-01

Trabeculectomy has been the traditional primary surgical therapy for open-angle glaucoma. While trabeculectomy is effective in lowering intraocular pressure, complications associated with the procedure have motivated the development of alternative techniques and devices, including the EX-PRESS Glaucoma Filtration Device. This review describes the efficacy, safety, complication rates, and potential advantages and disadvantages of the EX-PRESS Glaucoma Filtration Device. EX-PRESS implantation is technically simpler compared with that of trabeculectomy, with fewer surgical steps. Vision recovery has been more rapid after EX-PRESS implantation compared with trabeculectomy. Intraocular pressure variation is lower during the early postoperative period, indicating a more predictable procedure. While efficacy of the EX-PRESS implant has been comparable to trabeculectomy, postoperative complications appear less common after EX-PRESS implantation compared with trabeculectomy. The EX-PRESS Glaucoma Filtration Device appears to be safe and effective in the surgical management of open-angle glaucoma. PMID:26366105

Sediment filtration can reduce the N load of the waste water discharge - a full-scale lake experiment

NASA Astrophysics Data System (ADS)

Aalto, Sanni L.; Saarenheimo, Jatta; Karvinen, Anu; Rissanen, Antti J.; Ropponen, Janne; Juntunen, Janne; Tiirola, Marja

2016-04-01

European commission has obliged Baltic states to reduce nitrate load, which requires high investments on the nitrate removal processes and may increase emissions of greenhouse gases, e.g. N2O, in the waste water treatment plants. We used ecosystem-scale experimental approach to test a novel sediment filtration method for economical waste water N removal in Lake Keurusselkä, Finland between 2014 and 2015. By spatially optimizing the waste water discharge, the contact area and time of nitrified waste water with the reducing microbes of the sediment was increased. This was expected to enhance microbial-driven N transformation and to alter microbial community composition. We utilized 15N isotope pairing technique to follow changes in the actual and potential denitrification rates, nitrous oxide formation and dissimilatory nitrate reduction to ammonium (DNRA) in the lake sediments receiving nitrate-rich waste water input and in the control site. In addition, we investigated the connections between observed process rates and microbial community composition and functioning by using next generation sequencing and quantitative PCR. Furthermore, we estimated the effect of sediment filtration method on waste water contact time with sediment using the 3D hydrodynamic model. We sampled one year before the full-scale experiment and observed strong seasonal patterns in the process rates, which reflects the seasonal variation in the temperature-related mixing patterns of the waste water within the lake. During the experiment, we found that spatial optimization enhanced both actual and potential denitrification rates of the sediment. Furthermore, it did not significantly promote N2O emissions, or N retention through DNRA. Overall, our results indicate that sediment filtration can be utilized as a supplemental or even alternative method for the waste water N removal.

Prevalence of and risk factors for reduced serum bicarbonate in chronic kidney disease.

PubMed

Raphael, Kalani L; Zhang, Yingying; Ying, Jian; Greene, Tom

2014-10-01

The prevalence of metabolic acidosis increases as glomerular filtration rate falls. However, most patients with stage 4 chronic kidney disease have normal serum bicarbonate concentration while some with stage 3 chronic kidney disease have low serum bicarbonate, suggesting that other factors contribute to generation of acidosis. The purpose of this study is to identify risk factors, other than reduced glomerular filtration rate, for reduced serum bicarbonate in chronic kidney disease. This is a cross-sectional analysis of baseline data from the Chronic Renal Insufficiency Cohort Study. Multivariable logistic and linear regression models were used to relate predictor variables to the odds of low serum bicarbonate (< 22 mM) compared with normal serum bicarbonate (22-30 mM) and the coefficients of Δ serum bicarbonate concentration. The prevalence of low serum bicarbonate at baseline was 17.3%. Lower estimated glomerular filtration rate had the strongest relationship with low serum bicarbonate. Factors associated with higher odds of low serum bicarbonate, independent of estimated glomerular filtration rate, were urinary albumin/creatinine ≥ 10 mg/g, smoking, anaemia, hyperkalaemia, non-diuretic use and higher serum albumin. These and younger age, higher waist circumference, and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers associated with negative Δ serum bicarbonate in linear regression models. Several factors not typically considered to associate with reduced serum bicarbonate in chronic kidney disease were identified including albuminuria ≥ 10 mg/g, anaemia, smoking, higher serum albumin, higher waist circumference, and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers. Future studies should explore the longitudinal effect of these factors on serum bicarbonate concentration. © 2014 Asian Pacific Society of Nephrology.

Serum uric acid to creatinine ratio: A predictor of incident chronic kidney disease in type 2 diabetes mellitus patients with preserved kidney function.

PubMed

Gu, Liubao; Huang, Liji; Wu, Haidi; Lou, Qinglin; Bian, Rongwen

2017-05-01

Serum uric acid has shown to be a predictor of renal disease progression in most but not all studies. This study aims to test whether renal function-normalized serum uric acid is superior to serum uric acid as the predictor of incident chronic kidney disease in type 2 diabetes mellitus patients. In this study, 1339 type 2 diabetes mellitus patients with estimated glomerular filtration rate ⩾60 mL/min/1.73 m 2 and normouricemia were included. Renal function-normalized serum uric acid was calculated using serum uric acid/creatinine. Cox regression analysis was used to estimate the association between serum uric acid, renal function-normalized serum uric acid and incident chronic kidney disease. In total, 74 (5.53%) patients developed to chronic kidney disease 3 or greater during a median follow-up of 4 years, with older ages, longer diabetes duration and lower estimated glomerular filtration rate at baseline. The decline rate of estimated glomerular filtration rate was positively correlated with serum uric acid/creatinine ( r = 0.219, p < 0.001), but not serum uric acid ( r = 0.005, p = 0.858). Moreover, multivariate analysis revealed that serum uric acid was not an independent risk factor for incident chronic kidney disease ( p = 0.055), whereas serum uric acid to creatinine ratio was significantly associated with incident chronic kidney disease independently of potential confounders including baseline estimated glomerular filtration rate. serum uric acid to creatinine ratio might be a better predictor of incident chronic kidney disease in type 2 diabetes mellitus patients.

Association of Pulse Wave Velocity With Chronic Kidney Disease Progression and Mortality: Findings From the CRIC Study (Chronic Renal Insufficiency Cohort).

PubMed

Townsend, Raymond R; Anderson, Amanda Hyre; Chirinos, Julio A; Feldman, Harold I; Grunwald, Juan E; Nessel, Lisa; Roy, Jason; Weir, Matthew R; Wright, Jackson T; Bansal, Nisha; Hsu, Chi-Yuan

2018-06-01

Patients with chronic kidney diseases (CKDs) are at risk for further loss of kidney function and death, which occur despite reasonable blood pressure treatment. To determine whether arterial stiffness influences CKD progression and death, independent of blood pressure, we conducted a prospective cohort study of CKD patients enrolled in the CRIC study (Chronic Renal Insufficiency Cohort). Using carotid-femoral pulse wave velocity (PWV), we examined the relationship between PWV and end-stage kidney disease (ESRD), ESRD or halving of estimated glomerular filtration rate, or death from any cause. The 2795 participants we enrolled had a mean age of 60 years, 56.4% were men, 47.3% had diabetes mellitus, and the average estimated glomerular filtration rate at entry was 44.4 mL/min per 1.73 m 2 During follow-up, there were 504 ESRD events, 628 ESRD or halving of estimated glomerular filtration rate events, and 394 deaths. Patients with the highest tertile of PWV (>10.3 m/s) were at higher risk for ESRD (hazard ratio [95% confidence interval], 1.37 [1.05-1.80]), ESRD or 50% decline in estimated glomerular filtration rate (hazard ratio [95% confidence interval], 1.25 [0.98-1.58]), or death (hazard ratio [95% confidence interval], 1.72 [1.24-2.38]). PWV is a significant predictor of CKD progression and death in people with impaired kidney function. Incorporation of PWV measurements may help define better the risks for these important health outcomes in patients with CKDs. Interventions that reduce aortic stiffness deserve study in people with CKD. © 2018 American Heart Association, Inc.

Prolonged Baroreflex Activation Abolishes Salt-Induced Hypertension After Reductions in Kidney Mass.

PubMed

Hildebrandt, Drew A; Irwin, Eric D; Lohmeier, Thomas E

2016-12-01

Chronic electric activation of the carotid baroreflex produces sustained reductions in sympathetic activity and arterial pressure and is currently being evaluated for therapy in patients with resistant hypertension. However, patients with significant impairment of renal function have been largely excluded from clinical trials. Thus, there is little information on blood pressure and renal responses to baroreflex activation in subjects with advanced chronic kidney disease, which is common in resistant hypertension. Changes in arterial pressure and glomerular filtration rate were determined in 5 dogs after combined unilateral nephrectomy and surgical excision of the poles of the remaining kidney to produce ≈70% reduction in renal mass. After control measurements, sodium intake was increased from ≈45 to 450 mol/d. While maintained on high salt, animals experienced increases in mean arterial pressure from 102±4 to 121±6 mm Hg and glomerular filtration rate from 40±2 to 45±2 mL/min. During 7 days of baroreflex activation, the hypertension induced by high salt was abolished (103±6 mm Hg) along with striking suppression of plasma norepinephrine concentration from 139±21 to 81±9 pg/mL, but despite pronounced blood pressure lowering, there were no significant changes in glomerular filtration rate (43±2 mL/min). All variables returned to prestimulation values during a recovery period. These findings indicate that after appreciable nephron loss, chronic suppression of central sympathetic outflow by baroreflex activation abolishes hypertension induced by high salt intake. The sustained antihypertensive effects of baroreflex activation occur without significantly compromising glomerular filtration rate in remnant nephrons. © 2016 American Heart Association, Inc.

Impact of proteinuria and glomerular filtration rate on risk of ischaemic and intracerebral hemorrhagic stroke: a result from the Kailuan study.

PubMed

Li, Z; Wang, A; Cai, J; Gao, X; Zhou, Y; Luo, Y; Wu, S; Zhao, X

2015-02-01

Persons with chronic kidney disease, defined by a reduced estimated glomerular filtration rate and proteinuria, have an increased risk of cardiovascular disease including stroke. However, data from developing countries are limited. Our aim was to assess the relationship between chronic kidney disease and risk of stroke and its subtypes in a community-based population in China. The study was based on 92,013 participants (18-98 years old; 73,248 men and 18,765 women) of the Kailuan study who at baseline were free from stroke and myocardial infarction and had undergone tests for serum creatinine or proteinuria. Glomerular filtration rate was estimated using the Chronic Kidney Disease Epidemiology Collaboration formula and proteinuria by the urine dipstick result in laboratory databases. The primary outcome was the first occurrence of stroke. Data were analyzed using Cox proportional hazards models adjusted for relevant confounders and results are presented as hazard ratios (HRs) with 95% confidence intervals (CIs). During a follow-up of 4 years, 1575 stroke events (1128 ischaemic, 406 intracerebral hemorrhagic and 41 subarachnoid hemorrhagic strokes) occurred. After adjustment for variable confounders, patients with proteinuria were found to have increased HRs for the total and subtypes of stroke events (HR 1.61; 95% CI 1.35-1.92 for total stroke; HR 1.53; 95% CI 1.24-1.89 for ischaemic stroke; and HR 1.90; 95% CI 1.35-2.67 for hemorrhagic stroke). However, estimated glomerular filtration rate was not associated with incident stroke after adjustment for established cardiovascular risk factors. Proteinuria increased the risk of stroke in a general Chinese population. © 2014 EAN.

Dynamic Decision Making under Uncertainty and Partial Information

DTIC Science & Technology

2013-11-14

integral under the natural filtration generated by the Brownian motions . This compact expression potentially enables us to design sub- optimal penalties...bounds on bermudan option price under jump diffusion processes. Quantitative Finance , 2013. Under review, available at http://arxiv.org/abs/1305.4321... Finance , 19:53 – 71, 2009. [3] D.P. Bertsekas. Dynamic Programming and Optimal Control. Athena Scientific, 4th edition, 2012. [4] D.B. Brown and J.E

Bromate formation in a hybrid ozonation-ceramic membrane filtration system.

PubMed

Moslemi, Mohammadreza; Davies, Simon H; Masten, Susan J

2011-11-01

The effect of pH, ozone mass injection rate, initial bromide concentration, and membrane molecular weight cut off (MWCO) on bromate formation in a hybrid membrane filtration-ozonation reactor was studied. Decreasing the pH, significantly reduced bromate formation. Bromate formation increased with increasing gaseous ozone mass injection rate, due to increase in dissolved ozone concentrations. Greater initial bromide concentrations resulted in higher bromate concentrations. An increase in the bromate concentration was observed by reducing MWCO, which resulted in a concomitant increase in the retention time in the system. A model to estimate the rate of bromate formation was developed. Good correlation between the model simulation and the experimental data was achieved. Copyright © 2011 Elsevier Ltd. All rights reserved.

The synthetic triterpenoid, RTA405, increases glomerular filtration rate and reduces angiotensin II-induced contraction of glomerular mesangial cells

PubMed Central

Ding, Yanfeng; Stidham, Rhesa; Bumeister, Ron; Trevino, Isaac; Winters, Ali; Sprouse, Marc; Ding, Min; Ferguson, Deborah A.; Meyer, Colin J.; Wigley, W. Christian; Ma, Rong

2012-01-01

Bardoxolone methyl, a synthetic triterpenoid, improves the estimated glomerular filtration rate (GFR) in patients with chornic kidney disease and type 2 diabetes. Since the contractile activity of mesangial cells may influence glomerular filtration, we evaluated the effect of the synthetic triterpenoid RTA405 with structural similarity to bardoxolone methyl, on GFR in rats and on mesangial cell contractility in freshly isolated glomeruli. In rats, RTA 405 increased basal GFR, assessed by inulin clearance, and attenuated the angiotensin II-induced decline in GFR. RTA 405 increased the filtration fraction, but did not affect arterial blood pressure or renal plasma flow. Glomeruli from RTA 405-treated rats were resistant to angiotensin II-induced volume reduction ex vivo. In cultured mesangial cells, angiotensin II-stimulated contraction was attenuated by RTA 405, in a dose- and time-dependent fashion. Further, Nrf2 targeted gene transcription (regulates antioxidant, anti-inflammatory, and cytoprotective responses) in mesangial cells was associated with decreased basal and reduced angiotensin II-stimulated hydrogen peroxide and calcium ion levels. These mechanisms contribute to the GFR increase that occurs following treatment with RTA 405 in rats and may underlie the effect of bardoxolone methyl on the estimated GFR in patients. PMID:23235569

The synthetic triterpenoid, RTA 405, increases the glomerular filtration rate and reduces angiotensin II-induced contraction of glomerular mesangial cells.

PubMed

Ding, Yanfeng; Stidham, Rhesa D; Bumeister, Ron; Trevino, Isaac; Winters, Ali; Sprouse, Marc; Ding, Min; Ferguson, Deborah A; Meyer, Colin J; Wigley, W Christian; Ma, Rong

2013-05-01

Bardoxolone methyl, a synthetic triterpenoid, improves the estimated glomerular filtration rate (GFR) in patients with chronic kidney disease and type 2 diabetes. Since the contractile activity of mesangial cells may influence glomerular filtration, we evaluated the effect of the synthetic triterpenoid RTA 405, with structural similarity to bardoxolone methyl, on GFR in rats and on mesangial cell contractility in freshly isolated glomeruli. In rats, RTA 405 increased basal GFR, assessed by inulin clearance, and attenuated the angiotensin II-induced decline in GFR. RTA 405 increased the filtration fraction, but did not affect arterial blood pressure or renal plasma flow. Glomeruli from RTA 405-treated rats were resistant to angiotensin II-induced volume reduction ex vivo. In cultured mesangial cells, angiotensin II-stimulated contraction was attenuated by RTA 405, in a dose- and time-dependent fashion. Further, Nrf2-targeted gene transcription (regulates antioxidant, anti-inflammatory, and cytoprotective responses) in mesangial cells was associated with decreased basal and reduced angiotensin II-stimulated hydrogen peroxide and calcium ion levels. These mechanisms contribute to the GFR increase that occurs following treatment with RTA 405 in rats and may underlie the effect of bardoxolone methyl on the estimated GFR in patients.

Effect of injected rotenone on the production and composition of urine from the rainbow trout (Salmo gairdneri)

USGS Publications Warehouse

Erickson, D.A.; Gingerich, W.H.

1986-01-01

Renal function was evaluated in adult rainbow trout (Salmo gairdneri) dosed i.a. with rotenone at 225 and 275 μg/kg. The chemical composition of urine samples and urine flow rates collected over a 5-h pretreatment period were compared with hourly urine samples collected over a 5-h posttreatment period. Significant increases in osmolality and in concentrations of sodium, potassium, chloride, glucose, and total protein were observed in the urine of treated fish. Urine solute concentrations reached maximum values within 1 to 3 h after treatment and decreased thereafter, indicating that the effects were reversible. Concentrations of sodium and chloride were highly correlated in 2-h posttreatment urine samples at the low (r = 0.922) and high (r = 0.981) rotenone treatments. Urine flow rates were reduced in trout at each dose of rotenone but the decrease in volume of urine voided was not dose-dependent. In a separate study, [14C]polyethylene glycol was used as a filtration marker to determine the effect of rotenone treatment (225 &mu:g/kg) on urine flow rate, glomerular filtration rate, and renal water reabsorption. We showed that posttreatment urine flow rates were reduced partly by reduced glomerular filtration and partly by increased water reabsorption. Transient increases in plasma osmolality and hematocrit also were observed 0.5 h after rotenone treatment.

PERFORMANCE IMPROVEMENT OF CROSS-FLOW FILTRATION FOR HIGH LEVEL WASTE TREATMENT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duignan, M.; Nash, C.; Poirier, M.

2011-01-12

In the interest of accelerating waste treatment processing, the DOE has funded studies to better understand filtration with the goal of improving filter fluxes in existing cross-flow equipment. The Savannah River National Laboratory (SRNL) was included in those studies, with a focus on start-up techniques, filter cake development, the application of filter aids (cake forming solid precoats), and body feeds (flux enhancing polymers). This paper discusses the progress of those filter studies. Cross-flow filtration is a key process step in many operating and planned waste treatment facilities to separate undissolved solids from supernate slurries. This separation technology generally has themore » advantage of self-cleaning through the action of wall shear stress created by the flow of waste slurry through the filter tubes. However, the ability of filter wall self-cleaning depends on the slurry being filtered. Many of the alkaline radioactive wastes are extremely challenging to filtration, e.g., those containing compounds of aluminum and iron, which have particles whose size and morphology reduce permeability. Unfortunately, low filter flux can be a bottleneck in waste processing facilities such as the Savannah River Modular Caustic Side Solvent Extraction Unit and the Hanford Waste Treatment Plant. Any improvement to the filtration rate would lead directly to increased throughput of the entire process. To date increased rates are generally realized by either increasing the cross-flow filter axial flowrate, limited by pump capacity, or by increasing filter surface area, limited by space and increasing the required pump load. SRNL set up both dead-end and cross-flow filter tests to better understand filter performance based on filter media structure, flow conditions, filter cleaning, and several different types of filter aids and body feeds. Using non-radioactive simulated wastes, both chemically and physically similar to the actual radioactive wastes, the authors performed several tests to demonstrate increases in filter performance. With the proper use of filter flow conditions and filter enhancers, filter flow rates can be increased over rates currently realized today.« less

Using Mathematical Algorithms to Modify Glomerular Filtration Rate Estimation Equations

PubMed Central

Zhu, Bei; Wu, Jianqing; Zhu, Jin; Zhao, Weihong

2013-01-01

Background The equations provide a rapid and low-cost method of evaluating glomerular filtration rate (GFR). Previous studies indicated that the Modification of Diet in Renal Disease (MDRD), Chronic Kidney Disease-Epidemiology (CKD-EPI) and MacIsaac equations need further modification for application in Chinese population. Thus, this study was designed to modify the three equations, and compare the diagnostic accuracy of the equations modified before and after. Methodology With the use of 99 mTc-DTPA renal dynamic imaging as the reference GFR (rGFR), the MDRD, CKD-EPI and MacIsaac equations were modified by two mathematical algorithms: the hill-climbing and the simulated-annealing algorithms. Results A total of 703 Chinese subjects were recruited, with the average rGFR 77.14±25.93 ml/min. The entire modification process was based on a random sample of 80% of subjects in each GFR level as a training sample set, the rest of 20% of subjects as a validation sample set. After modification, the three equations performed significant improvement in slop, intercept, correlated coefficient, root mean square error (RMSE), total deviation index (TDI), and the proportion of estimated GFR (eGFR) within 10% and 30% deviation of rGFR (P10 and P30). Of the three modified equations, the modified CKD-EPI equation showed the best accuracy. Conclusions Mathematical algorithms could be a considerable tool to modify the GFR equations. Accuracy of all the three modified equations was significantly improved in which the modified CKD-EPI equation could be the optimal one. PMID:23472113

Analysis of the pressure-induced potential arising through composite membranes with selective surface layers.

PubMed

Szymczyk, Anthony; Sbaï, Mohammed; Fievet, Patrick

2005-03-01

When a pressure gradient is applied through a charged selective membrane, the transmembrane electrical potential difference, called the filtration potential, results from both the applied pressure and induced concentration difference across the membrane. In this work we investigate the electrokinetic properties relative to both active and support layers of a composite ceramic membrane close to the nanofiltration range. First, the volume charge density of the active layer is obtained by fitting a transport model to experimental rejection rates (which are controlled by the active layer only). Next, the value of the volume charge density is used to compute the theoretical filtration potential through the active layer. For sufficiently high permeate volume fluxes, the concentration difference across the active layer becomes constant, which allows assessing the membrane potential of the active layer. Experimental measurements of the overall filtration potential arising through the whole membrane are performed. The contribution of the support layer to this overall filtration potential is put in evidence. That implies that the membrane potential of the active layer cannot be deduced directly from the overall filtration potential measurements. Finally, the contribution of the support layer is singled out by subtracting the theoretical filtration potential of the active layer from the experimental filtration potential measured across the whole membrane (i.e., support + active layers). The amphoteric behavior of both layers is put in evidence, which is confirmed by electrophoretic measurements carried out with the powdered support layer and by recently reported tangential streaming potential measurements.

DMSP and DMS dynamics and microzooplankton grazing in the Labrador Sea: application of the dilution technique

NASA Astrophysics Data System (ADS)

Wolfe, Gordon V.; Levasseur, Maurice; Cantin, Guy; Michaud, Sonia

2000-12-01

We adapted the dilution technique to study microzooplankton grazing of algal dimethylsulfoniopropionate (DMSP) vs. Chl a, and to estimate the impact of microzooplankton grazing on dimethyl sulfide (DMS) production in the Labrador Sea. Phytoplankton numbers were dominated by autotrophic nanoflagellates in the Labrador basin, but diatoms and colonial Phaeocystis pouchetii contributed significantly to phytomass at several high chlorophyll stations and on the Newfoundland and Greenland shelfs. Throughout the region, growth of algal Chl a and DMSP was generally high (0.2-1 d -1), but grazing rates were lower and more variable, characteristic of the early spring bloom period. Production and consumption of Chl a vs. DMSP followed no clear pattern, and sometimes diverged greatly, likely because of their differing distributions among algal prey taxa and size class. In several experiments where Phaeocystis was abundant, we observed DMS production proportional to grazing rate, and we found clear evidence of DMS production by this haptophyte following physical stress such as sparging or filtration. It is possible that grazing-activated DMSP cleavage by Phaeocystis contributes to grazer deterrence: protozoa and copepods apparently avoided healthy colonies (as judged by relative growth and grazing rates of Chl a and DMSP), and grazing of Phaeocystis was significant only at one station where cells were in poor condition. Although we hoped to examine selective grazing on or against DMSP-containing algal prey, the dilution technique cannot differentiate selective ingestion and varying digestion rates of Chl a and DMSP. We also found that the dilution method alone was poorly suited for assessing the impact of grazing on dissolved sulfur pools, because of rapid microbial consumption and the artifactual release of DMSP and DMS during filtration. Measuring and understanding the many processes affecting organosulfur cycling by the microbial food web in natural populations remain a technical challenge that will likely require a combination of techniques to address.

Performance evaluation of different filter media in turbidity removal from water by application of modified qualitative indices.

PubMed

Gholikandi, G Badalians; Dehghanifard, E; Sepehr, M Noori; Torabian, A; Moalej, S; Dehnavi, A; Yari, Ar; Asgari, Ar

2012-01-01

Water filtration units have been faced problems in water turbidity removal related to their media, which is determined by qualitative indices. Moreover, Current qualitative indices such as turbidity and escaping particle number could not precisely determine the efficiency of the media in water filtration, so defining new indices is essential. In this study, the efficiency of Anthracite-Silica and LECA-Silica media in turbidity removal were compared in different operating condition by using modified qualitative indices. The pilot consisted of a filter column (one meter depth) which consisted of a layer of LECA (450 mm depth) and a layer of Silica sand (350 mm depth. Turbidities of 10, 20, and 30 NTU, coagulant concentrations of 4, 8, and 12 ppm and filtration rates of 10, 15, and 20 m/h were considered as variables. The LECA-Silica media is suitable media for water filtration. Averages of turbidity removal efficiencies in different condition for the LECA-Silica media were 85.8±5.37 percent in stable phase and 69.75±3.37 percent in whole operation phase, while the efficiency of total system were 98.31±0.63 and 94.49±2.97 percent, respectively. The LECA layer efficiency in turbidity removal was independent from filtration rates and due to its low head loss; LECA can be used as a proper medium for treatment plants. Results also showed that the particle index (PI) was a suitable index as a substitute for turbidity and EPN indices.

Pilot-scale investigation on the removal of organic foulants in secondary effluent by slow sand filtration prior to ultrafiltration.

PubMed

Zheng, Xing; Ernst, Mathias; Jekel, Martin

2010-05-01

Natural biofiltration processes have been verified as effective pre-treatment choice improving the performance of low-pressure membranes (MF/UF) in wastewater reclamation. In the present work, pilot-scale slow sand filtration (SSF) was used to simulate bank filtration at high filtration rates (from 0.25m/h to 0.5m/h) to filter secondary effluent prior to UF. The results showed that SSF improved the performance of UF to a large extent. Related to previous work biopolymers are considered as major dissolved organic foulants in treated wastewater. The removal of these organic foulants in slow sand filters and factors affecting the performance of SSF were investigated. It was observed that the removal of biopolymers took place mainly at the upper sand layer and was related to biological degradation. Tests on the degradability of biopolymers verified that they are biodegradable. Sixteen months monitoring of biopolymer concentration in the secondary effluent indicated that it varied seasonally. In winter season the concentration was much higher than during the summer months. Higher temperature and lower biopolymer concentration led to more effective foulants removal and more sustainable operation of SSF. During the whole experimental period, the performance of SSF was always better at filtration rate of 0.25m/h than at 0.5m/h. Under the present experimental conditions, SSF exhibited stable and effective biopolymer removal at temperatures higher than 15 degrees C, at biopolymer concentrations lower than 0.5mg C/L and with sufficient oxygen available.

A scalable, micropore, platelet rich plasma separation device.

PubMed

Dickson, Mary Nora; Amar, Levy; Hill, Michael; Schwartz, Joseph; Leonard, Edward F

2012-12-01

We have designed a novel, low energy platelet-rich-plasma (PRP) separator capable of producing 50 mL of PRP in 30 min, intended for military and emergency applications. Blood flows over a 3 mm length of sieve at high rates of shear. A plasma-platelet filtrate passes through the sieve's pores while erythrocytes remain. The filtrate is flowed over a second 3 mm length of smaller-pored sieve that withdraws plasma. Bulk blood volume is maintained by returning platelet-free plasma to the erythrocyte pool, enabling a nearly complete multi-pass platelet extraction. The total percentage of platelets extracted is:θ(T)=1-exp (-V(f)(T)Φ(P)/V) where V is the original plasma volume, V ( f )(T) is the total filtered volume, and ϕ ( P ) is platelet passage ratio (filtrate concentration/bulk average concentration) taken to be constant. Maximum θ(T) occurs at maximum V ( f )(T)× ϕ ( P ) Test microsieves, 3 mm long × 3 mm wide, were used. ϕ ( P ) values measured at various filtrate flow rates (20-100 uL/min) and utilizing various filter pore sizes (1.2-3.5 μm), was as high as 150 %. Maximum V ( f )(T)× ϕ ( P ) was achieved utilizing the 3.5 um filters at the highest flow rate, 100 uL/min. Erythrocyte leakages were always below 2,000/uL, far below the allowable limit stipulated by the American Association of Blood Banking. These data imply that a 13.7 cm(2) filter area is sufficient to achieve the target separation of 50 mL of platelet concentrate in 30 min. The filtration cartridge would consist of multiple microporous strips of 3 mm width arranged in parallel so that each element would see the conditions used in the prototype experiments presented here. Other microfiltration schemes suggest no method of scaling to practical levels.

Predictive Power of Clean Bed Filtration Theory for Fecal Indicator Bacteria Removal in Stormwater Biofilters

NASA Astrophysics Data System (ADS)

Parker, E.; Rippy, M.; Mehring, A.; Winfrey, B.; Ambrose, R. F.; Levin, L. A.; Grant, S. B.

2017-12-01

Green infrastructure (also referred to as low impact development, or LID) has the potential to transform urban stormwater runoff from an environmental threat to a valuable water resource. Here we focus on the removal of fecal indicator bacteria (FIB, a pollutant responsible for runoff associated inland and coastal beach closures) in stormwater biofilters (a common type of green infrastructure). Drawing on a combination of previously published and new laboratory studies of FIB removal in biofilters, we find that 66% of the variance in FIB removal rates can be explained by clean bed filtration theory (CBFT, 31%), antecedent dry period (14%), study effect (8%), biofilter age (7%), and the presence or absence of shrubs (6%). Our analysis suggests that, with the exception of shrubs, plants affect FIB removal indirectly by changing the infiltration rate, not directly by changing the FIB removal mechanisms or altering filtration rates in ways not already accounted for by CBFT. The analysis presented here represents a significant step forward in our understanding of how physicochemical theories (such as CBFT) can be melded with hydrology, engineering design, and ecology to improve the water quality benefits of green infrastructure.

Clinical and Biochemical Characteristics of Brain-Dead Donors as Predictors of Early- and Long-Term Renal Function After Transplant.

PubMed

Kwiatkowska, Ewa; Domański, Leszek; Bober, Joanna; Safranow, Krzysztof; Pawlik, Andrzej; Ciechanowski, Kazimierz; Wiśniewska, Magda; Kędzierska, Karolina

2017-08-01

Organs from brain-dead donors are the main source of allografts for transplant. Comparisons between living-donor and brain-dead donor kidneys show that the latter are more likely to demonstrate delayed graft function and lower long-term survival. This study aimed to assess the effects of various clinical and biochemical factors of donors on early- and long-term renal function after transplant. We analyzed data from kidney recipients treated between 2006 and 2008 who received organs from brain-dead donors. Data from 54 donors and 89 recipients were analyzed. No relation was observed between donor sodium concentration and the presence of delayed graft function. Donor height was positively correlated with creatinine clearance in recipients in the 1 to 3 months after renal transplant. Donor diastolic blood pressure was negatively correlated with estimated glomerular filtration rate throughout the observation period. Donor age was negatively correlated with the allograft recipient's estimated glomerular filtration rate throughout 4 years of observation. Donor estimated glomerular filtration rate was positively correlated with that of the recipient throughout 3 years of observation. The results of this study indicate that various factors associated with allograft donors may influence graft function.

Accuracy and reproducibility of a new contrast clearance method for the determination of glomerular filtration rate.

PubMed Central

O'Reilly, P H; Brooman, P J; Martin, P J; Pollard, A J; Farah, N B; Mason, G C

1986-01-01

A new method for determining the glomerular filtration rate was analysed prospectively. The method uses an x ray fluorescence technique to measure disappearance from the plasma of injected non-ionic iodinated contrast media. Eighty seven patients were studied. Fifty four had an intravenous dose of 100 ml iohexol (Omnipaque) and 33 had 50 ml iohexol. Clearances of chromium-51 labelled edetic acid (51Cr-EDTA) were measured simultaneously. In the patients given 100 ml iohexol there was excellent correlation with 51Cr-EDTA clearance (r = 0.90). The correlation using 50 ml iohexol was also good (r = 0.85). Correlation between creatinine clearance and clearance of 51Cr-EDTA in 33 patients was less satisfactory (r = 0.69). There were no adverse reactions to the contrast media. The equipment used for measuring contrast clearance was robust and simple to operate. Freezing plasma samples in 10 studies and re-examining them weekly for six weeks showed no significant variation in results; hence reproducibility was good. This new and accurate method for determining the glomerular filtration rate merits further study and might find a useful place in routine clinical practice. Images FIG 1 PMID:3089467

Renal function, renal volume, and blood pressure in infants with antecedent of antenatal steroids.

PubMed

Carballo-Magdaleno, Deyanira; Guízar-Mendoza, Juan M; Amador-Licona, Norma; Domínguez-Domínguez, Víctor

2011-10-01

Steroids have been used for more than 20 years in preterm infants to induce pulmonary maturity; however, some long-term effects have been reported, such as insulin resistance and elevation of blood pressure. The aim of our study was to compare renal volume, renal function, and blood pressure in infants between 12-36 months of age with and without antecedent of antenatal steroid treatment. This was a cross-sectional study comprised of three groups of infants (n = 30, respectively): preterm infants with and without antecedent of receiving antenatal steroids, respectively, and full-term infants. Blood pressure, renal volume, glomerular filtration rate, and tubular function were measured. Blood pressure and cystatin C levels and glomerular filtration rate were higher in both groups of preterm infants than in the control group (p < 0.01). However, no difference in any of the tested variables between the steroid and non-steroid group of preterm infants. Renal volume was similar in preterm and control infants. Based on these results, we conclude that prematurity independent of antenatal steroid use is associated with higher cystatin C and blood pressure levels and a higher glomerular filtration rate in infants between 12-36 months of age.

Superiority of Serum Cystatin C Over Creatinine in Prediction of Long-Term Prognosis at Discharge From ICU.

PubMed

Ravn, Bo; Prowle, John R; Mårtensson, Johan; Martling, Claes-Roland; Bell, Max

2017-09-01

Renal outcomes after critical illness are seldom assessed despite strong correlation between chronic kidney disease and survival. Outside hospital, renal dysfunction is more strongly associated with mortality when assessed by serum cystatin C than by creatinine. The relationship between creatinine and longer term mortality might be particularly weak in survivors of critical illness. Retrospective observational cohort study. In 3,077 adult ICU survivors, we compared ICU discharge cystatin C and creatinine and their association with 1-year mortality. Exclusions were death within 72 hours of ICU discharge, ICU stay less than 24 hours, and end-stage renal disease. None. During ICU admission, serum cystatin C and creatinine diverged, so that by ICU discharge, almost twice as many patients had glomerular filtration rate less than 60 mL/min/1.73 m when estimated from cystatin C compared with glomerular filtration rate estimated from creatinine, 44% versus 26%. In 743 patients without acute kidney injury, where ICU discharge renal function should reflect ongoing baseline, discharge glomerular filtration rate estimated from creatinine consistently overestimated follow-up glomerular filtration rate estimated from creatinine, whereas ICU discharge glomerular filtration rate estimated from cystatin C well matched follow-up chronic kidney disease status. By 1 year, 535 (17.4%) had died. In survival analysis adjusted for age, sex, and comorbidity, cystatin C was near-linearly associated with increased mortality, hazard ratio equals to 1.78 (95% CI, 1.46-2.18), 75th versus 25th centile. Conversely, creatinine demonstrated a J-shaped relationship with mortality, so that in the majority of patients, there was no significant association with survival, hazard ratio equals to 1.03 (0.87-1.2), 75th versus 25th centile. After adjustment for both creatinine and cystatin C levels, higher discharge creatinine was then associated with lower long-term mortality. In contrast to creatinine, cystatin C consistently associated with long-term mortality, identifying patients at both high and low risk, and better correlated with follow-up renal function. Conversely, lower creatinine relative to cystatin C appeared to confer adverse prognosis, confounding creatinine interpretation in isolation. Cystatin C warrants further investigation as a more meaningful measure of renal function after critical illness.

Effect of renal denervation on dynamic autoregulation of renal blood flow.

PubMed

DiBona, Gerald F; Sawin, Linda L

2004-06-01

Vasoconstrictor intensities of renal sympathetic nerve stimulation elevate the renal arterial pressure threshold for steady-state stepwise autoregulation of renal blood flow. This study examined the tonic effect of basal renal sympathetic nerve activity on dynamic autoregulation of renal blood flow in rats with normal (Sprague-Dawley and Wistar-Kyoto) and increased levels of renal sympathetic nerve activity (congestive heart failure and spontaneously hypertensive rats). Steady-state values of arterial pressure and renal blood flow before and after acute renal denervation were subjected to transfer function analysis. Renal denervation increased basal renal blood flow in congestive heart failure (+35 +/- 3%) and spontaneously hypertensive rats (+21 +/- 3%) but not in Sprague-Dawley and Wistar-Kyoto rats. Renal denervation significantly decreased transfer function gain (i.e., improved autoregulation of renal blood flow) and increased coherence only in spontaneously hypertensive rats. Thus vasoconstrictor intensities of renal sympathetic nerve activity impaired the dynamic autoregulatory adjustments of the renal vasculature to oscillations in arterial pressure. Renal denervation increased renal blood flow variability in spontaneously hypertensive rats and congestive heart failure rats. The contribution of vasoconstrictor intensities of basal renal sympathetic nerve activity to limiting renal blood flow variability may be important in the stabilization of glomerular filtration rate.

Renal hemodynamics and renin-angiotensin system activity in humans with multifocal renal artery fibromuscular dysplasia.

PubMed

van Twist, Daan J L; Houben, Alphons J H M; de Haan, Michiel W; de Leeuw, Peter W; Kroon, Abraham A

2016-06-01

Fibromuscular dysplasia (FMD) is the second most common cause of renovascular hypertension. Nonetheless, knowledge on the renal microvasculature and renin-angiotensin system (RAS) activity in kidneys with FMD is scarce. Given the fairly good results of revascularization, we hypothesized that the renal microvasculature and RAS are relatively spared in kidneys with FMD. In 58 hypertensive patients with multifocal renal artery FMD (off medication) and 116 matched controls with essential hypertension, we measured renal blood flow (Xenon washout method) per kidney and drew blood samples from the aorta and both renal veins to determine renin secretion and glomerular filtration rate per kidney. We found that renal blood flow and glomerular filtration rate in FMD were comparable to those in controls. Although systemic renin levels were somewhat higher in FMD, renal renin secretion was not elevated. Moreover, in patients with unilateral FMD, no differences between the affected and unaffected kidney were observed with regard to renal blood flow, glomerular filtration rate, or renin secretion. In men, renin levels and renin secretion were higher as compared with women. The renal blood flow response to RAS modulation (by intrarenal infusion of angiotensin II, angiotensin-(1-7), an angiotensin II type 1 receptor blocker, or a nitric oxide synthase blocker) was also comparable between FMD and controls. Renal blood flow, glomerular filtration, and the response to vasoactive substances in kidneys with multifocal FMD are comparable to patients with essential hypertension, suggesting that microvascular function is relatively spared. Renin secretion was not increased and the response to RAS modulation was not affected in kidneys with FMD.

The Perspective of Riverbank Filtration in China

NASA Astrophysics Data System (ADS)

Li, J.; Teng, Y.; Zhai, Y.; Zuo, R.

2014-12-01

Sustainable drinking water supply can affect the health of people, and the surrounding ecosystems. According to statistics of the monitoring program of drinking water sources in 309 at or above prefecture level of China in 2013, the major pollutants index were total phosphorus, ammonia and manganese in surface drinking water sources, respectively, iron, ammonia and manganese in groundwater drinking water sources, respectively. More than 150 drinking water emergency environmental accidents happened since 2006, 52 of these accidents led to the disruption of water supply in waterworks, and a population of over ten million were affected. It indicated that there is a potential risk for people's health by the use of river water directly and it is necessary to require alternative techniques such as riverbank filtration for improving the drinking water quality. Riverbank filtration is an inexpensive natural process, not only smoothing out normal pollutant concentration found in surface water but also significantly reducing the risk from such emergency events as chemical spill into the river. Riverbank filtration technique has been used in many countries more than 100 years, including China. In China, in 1950s, the bank infiltration technique was first applied in northeast of China. Extensive bank infiltration application was conducted in 1980s, and more than 300 drinking water sources utilities bank infiltration established mainly near the Songhua River Basin, the Yellow River Basin, Haihe River Basin. However, the comparative lack of application and researches on riverbank filtration have formed critical scientific data gap in China. As the performance of riverbank filtration technique depend on not only the design and setting such as well type, pumping rate, but also the local hydrogeology and environmental properties. We recommend more riverbank filtration project and studies to be conducted to collect related significant environmental geology data in China. Additionally, the experience has demonstrated a number of water quality improvements associated with riverbank filtration. It is important to stress that the fate and behavior of emerging organic contaminants during riverbank filtration should be taken into special consideration.

Forced-air warming design: evaluation of intake filtration, internal microbial buildup, and airborne-contamination emissions.

PubMed

Reed, Mike; Kimberger, Oliver; McGovern, Paul D; Albrecht, Mark C

2013-08-01

Forced-air warming devices are effective for the prevention of surgical hypothermia. However, these devices intake nonsterile floor-level air, and it is unknown whether they have adequate filtration measures to prevent the internal buildup or emission of microbial contaminants. We rated the intake filtration efficiency of a popular current-generation forced-air warming device (Bair Hugger model 750, Arizant Healthcare) using a monodisperse sodium chloride aerosol in the laboratory. We further sampled 23 forced-air warming devices (same model) in daily hospital use for internal microbial buildup and airborne-contamination emissions via swabbing and particle counting. Laboratory testing found the intake filter to be 63.8% efficient. Swabbing detected microorganisms within 100% of the forced-air warming blowers sampled, with isolates of coagulase-negative staphylococci, mold, and micrococci identified. Particle counting showed 96% of forced-air warming blowers to be emitting significant levels of internally generated airborne contaminants out of the hose end. These findings highlight the need for upgraded intake filtration, preferably high-efficiency particulate air filtration (99.97% efficient), on current-generation forced-air warming devices to reduce contamination buildup and emission risks.

Water hammer reduces fouling during natural water ultrafiltration.

PubMed

Broens, F; Menne, D; Pothof, I; Blankert, B; Roesink, H D W; Futselaar, H; Lammertink, R G H; Wessling, M

2012-03-15

Today's ultrafiltration processes use permeate flow reversal to remove fouling deposits on the feed side of ultrafiltration membranes. We report an as effective method: the opening and rapid closing of a valve on the permeate side of an ultrafiltration module. The sudden valve closure generates pressure fluctuations due to fluid inertia and is commonly known as "water hammer". Surface water was filtrated in hollow fiber ultrafiltration membranes with a small (5%) crossflow. Filtration experiments above sustainable flux levels (>125 l (m2h)(-1)) show that a periodic closure of a valve on the permeate side improves filtration performance as a consequence of reduced fouling. It was shown that this effect depends on flux and actuation frequency of the valve. The time period that the valve was closed proved to have no effect on filtration performance. The pressure fluctuations generated by the sudden stop in fluid motion due to the valve closure are responsible for the effect of fouling reduction. High frequency recording of the dynamic pressure evolution shows water hammer related pressure fluctuations to occur in the order of 0.1 bar. The pressure fluctuations were higher at higher fluxes (higher velocities) which is in agreement with the theory. They were also more effective at higher fluxes with respect to fouling mitigation. Copyright © 2011 Elsevier Ltd. All rights reserved.

Mannitol increases renal blood flow and maintains filtration fraction and oxygenation in postoperative acute kidney injury: a prospective interventional study.

PubMed

Bragadottir, Gudrun; Redfors, Bengt; Ricksten, Sven-Erik

2012-08-17

Acute kidney injury (AKI), which is a major complication after cardiovascular surgery, is associated with significant morbidity and mortality. Diuretic agents are frequently used to improve urine output and to facilitate fluid management in these patients. Mannitol, an osmotic diuretic, is used in the perioperative setting in the belief that it exerts reno-protective properties. In a recent study on uncomplicated postcardiac-surgery patients with normal renal function, mannitol increased glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. Furthermore, experimental studies have previously shown that renal ischemia causes an endothelial cell injury and dysfunction followed by endothelial cell edema. We studied the effects of mannitol on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2), and extraction (RO2Ex) in early, ischemic AKI after cardiac surgery. Eleven patients with AKI were studied during propofol sedation and mechanical ventilation 2 to 6 days after complicated cardiac surgery. All patients had severe heart failure treated with one (100%) or two (73%) inotropic agents and intraaortic balloon pump (36%). Systemic hemodynamics were measured with a pulmonary artery catheter. RBF and renal filtration fraction (FF) were measured by the renal vein thermo-dilution technique and by renal extraction of chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), respectively. GFR was calculated as the product of FF and renal plasma flow RBF × (1-hematocrit). RVO2 and RO2Ex were calculated from arterial and renal vein blood samples according to standard formulae. After control measurements, a bolus dose of mannitol, 225 mg/kg, was given, followed by an infusion at a rate of 75 mg/kg/h for two 30-minute periods. Mannitol did not affect cardiac index or cardiac filling pressures. Mannitol increased urine flow by 61% (P < 0.001). This was accompanied by a 12% increase in RBF (P < 0.05) and a 13% decrease in renal vascular resistance (P < 0.05). Mannitol increased the RBF/cardiac output (CO) relation (P = 0.040). Mannitol caused no significant changes in RO2Ext or renal FF. Mannitol treatment of postoperative AKI induces a renal vasodilation and redistributes systemic blood flow to the kidneys. Mannitol does not affect filtration fraction or renal oxygenation, suggestive of balanced increases in perfusion/filtration and oxygen demand/supply.

Mannitol increases renal blood flow and maintains filtration fraction and oxygenation in postoperative acute kidney injury: a prospective interventional study

PubMed Central

2012-01-01

Introduction Acute kidney injury (AKI), which is a major complication after cardiovascular surgery, is associated with significant morbidity and mortality. Diuretic agents are frequently used to improve urine output and to facilitate fluid management in these patients. Mannitol, an osmotic diuretic, is used in the perioperative setting in the belief that it exerts reno-protective properties. In a recent study on uncomplicated postcardiac-surgery patients with normal renal function, mannitol increased glomerular filtration rate (GFR), possibly by a deswelling effect on tubular cells. Furthermore, experimental studies have previously shown that renal ischemia causes an endothelial cell injury and dysfunction followed by endothelial cell edema. We studied the effects of mannitol on renal blood flow (RBF), glomerular filtration rate (GFR), renal oxygen consumption (RVO2), and extraction (RO2Ex) in early, ischemic AKI after cardiac surgery. Methods Eleven patients with AKI were studied during propofol sedation and mechanical ventilation 2 to 6 days after complicated cardiac surgery. All patients had severe heart failure treated with one (100%) or two (73%) inotropic agents and intraaortic balloon pump (36%). Systemic hemodynamics were measured with a pulmonary artery catheter. RBF and renal filtration fraction (FF) were measured by the renal vein thermo-dilution technique and by renal extraction of chromium-51-ethylenediaminetetraacetic acid (51Cr-EDTA), respectively. GFR was calculated as the product of FF and renal plasma flow RBF × (1-hematocrit). RVO2 and RO2Ex were calculated from arterial and renal vein blood samples according to standard formulae. After control measurements, a bolus dose of mannitol, 225 mg/kg, was given, followed by an infusion at a rate of 75 mg/kg/h for two 30-minute periods. Results Mannitol did not affect cardiac index or cardiac filling pressures. Mannitol increased urine flow by 61% (P < 0.001). This was accompanied by a 12% increase in RBF (P < 0.05) and a 13% decrease in renal vascular resistance (P < 0.05). Mannitol increased the RBF/cardiac output (CO) relation (P = 0.040). Mannitol caused no significant changes in RO2Ext or renal FF. Conclusions Mannitol treatment of postoperative AKI induces a renal vasodilation and redistributes systemic blood flow to the kidneys. Mannitol does not affect filtration fraction or renal oxygenation, suggestive of balanced increases in perfusion/filtration and oxygen demand/supply. PMID:22901953

Evaluation of IDA-PEVA hollow fiber membrane metal ion affinity chromatography for purification of a histidine-tagged human proinsulin.

PubMed

de Aquino, Luciana Cristina Lins; de Sousa, Heloisa Ribeiro Tunes; Miranda, Everson Alves; Vilela, Luciano; Bueno, Sônia Maria Alves

2006-04-13

Inabilities to process particulate material and to allow the use of high flow rates are limitations of conventional chromatography. Membranes have been suggested as matrix for affinity separation due to advantages such as allowing high flow rates and low-pressure drops. This work evaluated the feasibility of using an iminodiacetic acid linked poly(ethylenevinyl alcohol) membrane in the immobilized metal ion affinity chromatography (IMAC) purification of a human proinsulin(His)(6) of an industrial insulin production process. The screening of metal ions showed Ni(2+) as metal with higher selectivity and capacity among the Cu(2+), Ni(2+), Zn(2+) and Co(2+). The membrane showed to be equivalent to conventional chelating beads in terms of selectivity and had a lower capacity (3.68 mg/g versus 12.26 mg/g). The dynamic adsorption capacity for human proinsulin(His)(6) was unaffected by the mode of operation (dead-end and cross-flow filtration).

TREATMENT AND SOLIDS MANAGEMENT

EPA Science Inventory

A variety of high-rate treatment methods show a potential to handle WWF including: physical separation with and without chemical addition (e.g., enhanced settling, fine-mesh screening, vortex separation, dual-media high-rate filtration, dissolved air flotation, activated carbon, ...

Studies on silver nanoparticles synthesized by a marine fungus, Penicillium fellutanum isolated from coastal mangrove sediment.

PubMed

Kathiresan, K; Manivannan, S; Nabeel, M A; Dhivya, B

2009-06-01

In this work, in vitro biosynthesis of silver nanoparticles was achieved using AgNO(3) as a substrate by Penicillium fellutanum isolated from coastal mangrove sediment. The biosynthesis was faster within minutes of silver ion coming in contact with the cell filtrate. Presence of silver nanoparticles in the culture filtrate was confirmed by absorption peak at 430 nm, as well under transmission electron microscope. The biosynthesis of nanoparticles was the maximum when the culture filtrate was treated with 1.0 mM AgNO(3), maintained at 0.3% NaCl and pH 6.0, incubated at 5 degrees C for 24h. The culture filtrate, precipitated with ammonium sulphate, was proved to have a single protein band with a molecular weight of 70 kDa using polyacrylamide gel electrophoresis. The present work highlighted the possibility of using the marine fungal strain of P. fellutanum to achieve a fast rate of nanoparticles synthesis.

Bio-filtration capacity, oxygen consumption and ammonium excretion of Dosinia ponderosa and Chione gnidia (Veneroida: Veneridae) from areas impacted and non-impacted by shrimp aquaculture effluents.

PubMed

Ramos-Corella, Karime; Martínez-Córdova, Luis Rafael; Enríquez-Ocaña, Luis Fernando; Miranda-Baeza, Anselmo; López-Elías, José Antonio

2014-09-01

Mollusks are some of the most important, abundant and diverse organisms inhabiting not only aquatic ecosystems, but also terrestrial environments. Recently, they have been used for bioremediation of aquaculture effluents; nevertheless, for that purpose it is necessary to analyze the capacity of a particular species. In this context, an experimental investigation was developed to evaluate the performance of two bivalves C. gnidia and D. ponderosa, collected from areas with or without shrimp aquaculture effluents. For this, the filtration capacity (as clearance rate) as well as the oxygen consumption and ammonia excretion rates were measured following standard methods. The clearance rate was significantly higher for D. ponderosa from impacted areas, when com- pared to C. gnidia, from both areas. Contrarily, the oxygen consumption was greater for C. gnidia from impacted areas compared to D. ponderosa from both areas. The same tendency was observed for the ammonia excretion with the highest rates observed for C. gnidia from impacted areas, whereas no differences were observed among D. ponderosa from both areas. The results suggest that both species developed different strategies to thrive and survive under the impacted conditions; D. ponderosa improved its filtration efficiency, while C. gnidia modified its oxygen consumption and ammonia excretion. We concluded that both species, and particularly D. ponderosa, can be used for bioremediation purposes.

Nutritional effects of culture media on mycoplasma cell size and removal by filtration.

PubMed

Folmsbee, Martha; Howard, Glenn; McAlister, Morven

2010-03-01

Careful media filtration prior to use is an important part of a mycoplasma contamination prevention program. This study was conducted to increase our knowledge of factors that influence efficient filtration of mycoplasma. The cell size of Acholeplasma laidlawii was measured after culture in various nutritional conditions using scanning electron microscopy. The maximum cell size changed, but the minimum cell size remained virtually unchanged and all tested nutritional conditions resulted in a population of cells smaller than 0.2 microm. Culture in Tryptic Soy Broth (TSB) resulted in an apparent increase in the percentage of very small cells which was not reflected in increased penetration of non-retentive 0.2 microm rated filters. A. laidlawii cultured in selected media formulations was used to challenge 0.2 microm rated filters using mycoplasma broth base as the carrier fluid. We used 0.2 microm rated filters as an analytical tool because A. laidlawii is known to penetrate 0.2 microm filters and the degrees of penetration can be compared. Culture of A. laidlawii in TSB resulted in cells that did not penetrate 0.2 microm rated filters to the same degree as cells cultured in other media such as mycoplasma broth or in TSB supplemented with 10% horse serum. (c) 2009 The International Association for Biologicals. Published by Elsevier Ltd. All rights reserved.

Circadian Rhythm of Glomerular Filtration and Solute Handling Related to Nocturnal Enuresis.

PubMed

Dossche, L; Raes, A; Hoebeke, P; De Bruyne, P; Vande Walle, J

2016-01-01

Although nocturnal polyuria in patients with monosymptomatic enuresis can largely be explained by the decreased nocturnal vasopressin secretion hypothesis, other circadian rhythms in the kidney also seem to have a role. We recently documented an absent day/night rhythm in a subgroup of desmopressin refractory cases. We explore the importance of abnormal circadian rhythm of glomerular filtration and tubular (sodium, potassium) parameters in patients with monosymptomatic enuresis. In this retrospective study of a tertiary enuresis population we collected data subsequent to a standardized screening (International Children's Continence Society questionnaire), 14-day diary for nocturnal enuresis and diuresis, and 24-hour concentration profile. The study population consisted of 139 children with nocturnal enuresis who were 5 years or older. Children with nonmonosymptomatic nocturnal enuresis were used as controls. There was a maintained circadian rhythm of glomerular filtration, sodium, osmotic excretion and diuresis rate in children with monosymptomatic and nonmonosymptomatic nocturnal enuresis, and there was no difference between the 2 groups. Secondary analysis revealed that in patients with nocturnal polyuria (with monosymptomatic or nonmonosymptomatic nocturnal enuresis) circadian rhythm of glomerular filtration, sodium and osmotic excretion, and diuresis rate was diminished in contrast to those without nocturnal polyuria (p <0.001). Circadian rhythm of the kidney does not differ between patients with nonmonosymptomatic and monosymptomatic enuresis. However, the subgroup with enuresis and nocturnal polyuria has a diminished circadian rhythm of nocturnal diuresis, sodium excretion and glomerular filtration in contrast to children without nocturnal polyuria. This observation cannot be explained by the vasopressin theory alone. Copyright © 2016 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers

PubMed Central

Buyel, Johannes F.; Gruchow, Hannah M.; Fischer, Rainer

2015-01-01

The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m−2 when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre–coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m−2 with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins. PMID:26734037

Investigation of a new in-line leukocyte reduction filter for packed red blood cells.

PubMed

Mönninghoff, J; Moog, R

2012-06-01

Occasionally there are adverse transfusion reactions in the therapeutic use of packed red blood cells. Some of those reactions are caused by the presence of white blood cells (WBCs). Both immunogenic and infectious transfusion reactions are significantly influenced by the level of white blood cell contamination. The flexible in-line red cell filtration system Leucoflex LCR Diamond (Macopharma) was investigated. According to manufacturer information the system has a smaller filter surface (46 cm(2)) than the previous filter LCR-5 (53 cm(2)). Main difference with the previous model is the rhomboid design. The filter tube connections are not at the level of the centre edge, but at two opposite corners. Eighteen red cell concentrates were produced under Good Manufacturing Practice conditions in routine operation. To ensure the quality of the filter system every 7 days metabolic parametres such as WBC count, haemoglobin content, haemolysis rate, potassium load, pH and ATP content were analysed over a storage period of 49 days. The mean product volume was 260.7 mL after filtration. Average haemoglobin content was 51.8 g per unit and WBC contamination was 0.02 × 10(6)per unit. Haemolysis rate was 0.05% directly after filtration and 0.20% at the end of storage. Immediately after filtration the potassium concentration was 1.3 mmol/L and the pH was 7.37. During whole storage time the ATP level was maintained above 2.0 μmol per g haemoglobin. The tested filtration system is suitable for quality-assured production of red blood cell concentrates meeting national and international guidelines. Copyright © 2012 Elsevier Ltd. All rights reserved.

Depth Filters Containing Diatomite Achieve More Efficient Particle Retention than Filters Solely Containing Cellulose Fibers.

PubMed

Buyel, Johannes F; Gruchow, Hannah M; Fischer, Rainer

2015-01-01

The clarification of biological feed stocks during the production of biopharmaceutical proteins is challenging when large quantities of particles must be removed, e.g., when processing crude plant extracts. Single-use depth filters are often preferred for clarification because they are simple to integrate and have a good safety profile. However, the combination of filter layers must be optimized in terms of nominal retention ratings to account for the unique particle size distribution in each feed stock. We have recently shown that predictive models can facilitate filter screening and the selection of appropriate filter layers. Here we expand our previous study by testing several filters with different retention ratings. The filters typically contain diatomite to facilitate the removal of fine particles. However, diatomite can interfere with the recovery of large biopharmaceutical molecules such as virus-like particles and aggregated proteins. Therefore, we also tested filtration devices composed solely of cellulose fibers and cohesive resin. The capacities of both filter types varied from 10 to 50 L m(-2) when challenged with tobacco leaf extracts, but the filtrate turbidity was ~500-fold lower (~3.5 NTU) when diatomite filters were used. We also tested pre-coat filtration with dispersed diatomite, which achieved capacities of up to 120 L m(-2) with turbidities of ~100 NTU using bulk plant extracts, and in contrast to the other depth filters did not require an upstream bag filter. Single pre-coat filtration devices can thus replace combinations of bag and depth filters to simplify the processing of plant extracts, potentially saving on time, labor and consumables. The protein concentrations of TSP, DsRed and antibody 2G12 were not affected by pre-coat filtration, indicating its general applicability during the manufacture of plant-derived biopharmaceutical proteins.

The substitution of sand filtration by immersed-UF for surface water treatment: pilot-scale studies.

PubMed

Lihua, Sun; Xing, Li; Guoyu, Zhang; Jie, Chen; Zhe, Xu; Guibai, Li

2009-01-01

The newly issued National Drinking Water Standard required that turbidity should be lower than 1 NTU, and the substitution of sand filtration by immersed ultrafiltration (immersed-UF) is feasible to achieve the standard. This study aimed to optimise the operational processes (i.e. aeration, backwashing) through pilot scale studies, to control membrane fouling while treating the sedimentation effluent. Results indicated that the immersed-UF was promising to treat the sedimentation effluent. The turbidity was below 0.10 NTU, bacteria and E. coli were not detected in the permeate water. The intermittent filtration with aeration is beneficial to inhibit membrane fouling. The critical aeration intensity is observed to be 60.0 m(3) m(-2) h(-1). At this aeration intensity, the decline rate of permeate flux in one period of backwashing was 1.94% and 7.03% for intermittent filtration and sustained filtration respectively. The different membrane backwashing methods (i.e. aeration 1.5 min, synchronous aeration and water backwashing 2 min, water backwashing 1.5 min; synchronous aeration and water backwashing 3 min, water backwashing 2 min; aeration 3 min, single water backwashing 2 min; synchronous aeration and water backwashing 5 min; single water backwashing 5 min) on the recovery of permeate flux were compared, indicating that the synchronous aeration and water backwashing exhibited best potential for permeate flux recovery. The optimal intensity of water backwashing is shown to be 90.0 L m(-2) h(-1). When the actual water intensity was below or exceeded the value, the recovery rate of permeate flux would be reduced. Additionally, the average operating cost for the immersed UF membrane, including the power, the chemical cleaning reagents, and membrane modules replacement, was about 0.31 RMB/m(3).

Benzene degradation in a denitrifying biofilm reactor: activity and microbial community composition.

PubMed

van der Waals, Marcelle J; Atashgahi, Siavash; da Rocha, Ulisses Nunes; van der Zaan, Bas M; Smidt, Hauke; Gerritse, Jan

2017-06-01

Benzene is an aromatic compound and harmful for the environment. Biodegradation of benzene can reduce the toxicological risk after accidental or controlled release of this chemical in the environment. In this study, we further characterized an anaerobic continuous biofilm culture grown for more than 14 years on benzene with nitrate as electron acceptor. We determined steady state degradation rates, microbial community composition dynamics in the biofilm, and the initial anaerobic benzene degradation reactions. Benzene was degraded at a rate of 0.15 μmol/mg protein/day and a first-order rate constant of 3.04/day which was fourfold higher than rates reported previously. Bacteria belonging to the Peptococcaceae were found to play an important role in this anaerobic benzene-degrading biofilm culture, but also members of the Anaerolineaceae were predicted to be involved in benzene degradation or benzene metabolite degradation based on Illumina MiSeq analysis of 16S ribosomal RNA genes. Biomass retention in the reactor using a filtration finger resulted in reduction of benzene degradation capacity. Detection of the benzene carboxylase encoding gene, abcA, and benzoic acid in the culture vessel indicated that benzene degradation proceeds through an initial carboxylation step.

3-D Modelling the effect of river excavation on surface water and groundwater relation in a bank filtration system - comparing electrical conductivity and heat as tracer

NASA Astrophysics Data System (ADS)

Wang, Weishi; Oswald, Sascha; Munz, Matthias; Strasser, Daniel

2017-04-01

As a pretreatment for conventional drinking water supply, bank filtration (BF) is widely used in Europe, while in Germany it contributes 16% of potable water supply. There are usually two crucial issues for BF influencing its treatment effect, which are separately the spatial and temporal distribution of travelling times and distinguishing between the flow contribution of BF versus inflow from the ambient groundwater. Modelling is a strong tool for analyzing the behavior and development of the flow field, especially for quantification of the river recharge rate of BF and estimation of travel time distribution. Though 3-D modelling of the flow field as a comprehensive tool has been used in several studies, many simulations are limited to pure water flow. Since heads are only partially able to constrain the flow field, model non-uniqueness might lead to misinterpretation of the real flow field, especially in complex geological conditions. Some studies have shown that by including tracers, the model non-uniqueness could be reasonably constrained and the accuracy of flux estimation could be improved. Natural tracers thus are used in groundwater modelling, while differences in their properties or input may cause dissimilar behavior during the transport process. In this study, we have set up a numerical 3-D groundwater flow model of a bank filtration site with strong geological heterogeneity and used the data of several years monitoring activities as the data basis. We were particularly interested in the seasonal dynamics but also structural changes induced by a reconstruction of the surface water including excavation and rebuilding the bank construction. By combining separately electrical conductivity and heat as tracers in the model we were able to i) understand flow field mechanisms and its changes caused by the excavation ii) conclude from the deviations of the tracer concentrations and dynamics simulated compared to the measurements on deficiencies of the flow field; and thus by the tracer study flow field could be improved iii) compare the individual behavior of the tracers in this realistic setting of transport processes also relevant for judging water quality in the pumping wells now and in the future.

Coupled fluid and solid mechanics study for improved permeability estimation of fines' invaded porous materials

NASA Astrophysics Data System (ADS)

Mirabolghasemi, M.; Prodanovic, M.

2012-12-01

The problem of fine particle infiltration is seen in fields from subsurface transport, to drug delivery to industrial slurry flows. Sediment filtration and pathogen retention are well-known subsurface engineering problems that have been extensively studied through different macroscopic, microscopic and experimental modeling techniques Due to heterogeneity, standard constitutive relationships and models yield poor predictions for flow (e.g. permeability) and rock properties (e.g. elastic moduli) of the invaded (damaged) porous media. This severely reduces our ability to, for instance, predict retention, pressure build-up, newly formed flow pathways or porous medium mechanical behavior. We chose a coupled computational fluid dynamics (CFD) - discrete element modeling (DEM) approach to simulate the particulate flow through porous media represented by sphere packings. In order to minimize the uncertainty involved in estimating the flow properties of porous media on Darcy scale and address the dynamic nature of filtration process, this microscopic approach is adapted as a robust method that can incorporate particle interaction physics as well as the heterogeneity of the porous medium.. The coupled simulation was done in open-source packages which has both CFD (openFOAM) and DEM components (LIGGGHTS). We ran several sensitivity analyses over different parameters such as particle/grain size ratio, fluid viscosity, flow rate and sphere packing porosity in order to investigate their effects on the depth of invasion and damaged porous medium permeability. The response of the system to the variation of different parameters is reflected through different clogging mechanism; for instance, bridging is the dominant mechanism of pore-throat clogging when larger particles penetrate into the packing, whereas, in case of fine particles which are much smaller than porous medium grains (1/20 in diameter), this mechanism is not very effective due to the frequent formation and destruction of particle bridges. Finally, depending on the material and fluids that penetrate into the porous medium, the ionic forces might play a significant role in the filtration process. We thus also report on influence of particle attachment (and detachment) on the type of clogging mechanisms. Pore scale simulations allow for visualization and understanding of fundamental processes, and, further, the velocity fields are integrated into a distinctly non-monotonic permeability-porosity/(depth of penetration) relationship.

Transcutaneous measurement of glomerular filtration rate in conscious laboratory animals: state of the art and future perspectives

NASA Astrophysics Data System (ADS)

Friedemann, Jochen; Schock-Kusch, Daniel; Shulhevich, Yury

2017-02-01

Transcutaneous measurement of Glomerular Filtration Rate (tGFR) is now frequently used in preclinical in vivo animal studies. tGFR allows consecutive measurements on the same animal, including multiple measurements on a daily basis. A description of the measurement device and its many applications, along with examples from the recent literature will be given. We will highlight the fields of interest in which the system is used and give an overview about its performance versus endogenous and other exogenous methods of GFR measurement. A special focus will be put on the precision of tGFR compared to standard measurements employed in the research setting.

Verification on the use of the Inoue method for precisely determining glomerular filtration rate in Philippine pediatrics

NASA Astrophysics Data System (ADS)

Magcase, M. J. D. J.; Duyan, A. Q.; Carpio, J.; Carbonell, C. A.; Trono, J. D.

2015-06-01

The objective of this study is to validate the Inoue method so that it would be the preferential choice in determining glomerular filtration rate (GFR) in Philippine pediatrics. The study consisted of 36 patients ranging from ages 2 months to 19 years old. The subjects used were those who were previously subjected to in-vitro method. The scintigrams of the invitro method was obtained and processed for split percentage uptake and for parameters needed to obtain Inoue GFR. The result of this paper correlates the Inoue GFR and In-vitro method (r = 0.926). Thus, Inoue method is a viable, simple, and practical technique in determining GFR in pediatric patients.

Preclinical evaluation of biodegradable macromolecular contrast agents for magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Feng, Yi

Macromolecular contrast agents have been shown to be superior to small molecular weight contrast agents for MRI in blood pool imaging, tumor diagnosis and grading. However, none has been approved by the FDA because they circulate in the bloodstream much longer than small molecular weight contrast agents and result in high tissue accumulation of toxic Gd(III) ions. Biodegradable macromolecular contrast agents (BMCA) were invented to alleviate the toxic accumulation. They have a cleavable disulfide bond based backbone that can be degraded in vivo and excreted out of the body via renal filtration. Furthermore, the side chain of the backbone can be modified to achieve various degradation rates. Three BMCA, (Gd-DTPA)-cystamine copolymers (GDCC), Gd-DTPA cystine copolymers (GDCP), and Gd-DTPA cystine diethyl ester copolymers (GDCEP), were evaluated as blood pool contrast agents in a rat model. They have excellent blood pool enhancement, preferred pharmacokinetics, and only minimal long-term tissue retention of toxic Gd(III) ions. GDCC and GDCP, the lead agents with desired degradation rates, with molecular weights of 20 KDa and 70 KDa, were chosen for dynamic contrast enhanced MRI (DCE-MRI) to differentiate human prostate tumor models of different malignancy and growth rates. GDCC and GDCP could differentiate these tumor models, providing more accurate estimations of plasma volume, flow leakage rate, and permeability surface area product than a small molecular weight contrast agent Gd-DTPA-BMA when compared to the prototype macromolecular contrast agent albumin-Gd-DTPA. GDCC was favored for its neutral charge side chain and reasonable uptake rate by the tumors. GDCC with a molecular weight of 40 KDa (GDCC-40, above the renal filtration cutoff size) was used to assess the efficacy of two photothermal therapies (interstitial and indocyanine green enhanced). GDCC-40 provided excellent tumor enhancement shortly after its injection. Acute tumor response (4 hr) after therapies was revealed by DCE-MRI using GDCC-40. The region of the tumor with suspicious uptake of GDCC-40 could be correlated to the residual tumor. With only minimum tissue accumulation, BMCA have applications in blood pool imaging, cancer diagnosis, and efficacy assessment of anticancer treatment. Therefore, BMCA are promising for clinical applications.

Effects of bombesin on erythropoietin production in the anaesthetized dog.

PubMed

Melchiorri, P; Sopranzi, N; Roseghini, M

1976-08-01

Bombesin, a tetradecapeptide isolated from the skin of some European discoglossid frogs, has been reported previously to reduce renal blood flow and glomerular filtration rate and to increase plasma renin activity in anaesthetized dogs. In the present study bombesin was infused intravenously in anaesthetized dogs at dose levels of 3, 6 and 12 ng/kg/min for 6 h and renal blood flow, glomerular filtration rate, oxygen consumption, oxygen extraction by the kidney tissue, as well as plasma erythropoietin levels (ESF) and plasma renin activity were measured. Plasma levels of ESF increased during bombesin infusion only when renal blood flow was reduced to a level of 1 ml/g/min or less. In this situation glomerular filtration was blocked, renal oxygen consumption was decreased to 10% of normal and oxygen extraction by the kidney was increased by 2 times. No correlation was found between plasma renin activity and ESF concentrations during bombesin infusion. It is concluded that the stimulant action of bombesin on ESF production is a consequence of the renal hypoxia induced by the reduction in renal blood flow.

Retinopathy and chronic kidney disease in the Chronic Renal Insufficiency Cohort (CRIC) study.

PubMed

Grunwald, Juan E; Alexander, Judith; Ying, Gui-Shuang; Maguire, Maureen; Daniel, Ebenezer; Whittock-Martin, Revell; Parker, Candace; McWilliams, Kathleen; Lo, Joan C; Go, Alan; Townsend, Raymond; Gadegbeku, Crystal A; Lash, James P; Fink, Jeffrey C; Rahman, Mahboob; Feldman, Harold; Kusek, John W; Xie, Dawei; Jaar, Bernard G

2012-09-01

To investigate the association between retinopathy and chronic kidney disease. In this observational, cross-sectional study, 2605 patients of the Chronic Renal Insufficiency Cohort (CRIC) study, a multicenter study of chronic kidney disease, were offered participation. Nonmydriatic fundus photographs of the disc and macula in both eyes were obtained in 1936 of these subjects. The photographs were reviewed in a masked fashion at a central photograph reading center using standard protocols. Presence and severity of retinopathy (diabetic, hypertensive, or other) and vessel diameter caliber were assessed by trained graders and a retinal specialist using protocols developed for large epidemiologic studies. Kidney function measurements and information on traditional and nontraditional risk factors for decreased kidney function were obtained from the CRIC study. Greater severity of retinopathy was associated with lower estimated glomerular filtration rate after adjustment for traditional and nontraditional risk factors. The presence of vascular abnormalities usually associated with hypertension was also associated with lower estimated glomerular filtration rate. We found no strong direct relationship between estimated glomerular filtration rate and average arteriolar or venular calibers. Our findings show a strong association between severity of retinopathy and its features and level of kidney function after adjustment for traditional and nontraditional risk factors for chronic kidney disease, suggesting that retinovascular pathology reflects renal disease.

High flux filtration medium based on nanofibrous substrate with hydrophilic nanocomposite coating.

PubMed

Wang, Xuefen; Chen, Xuming; Yoon, Kyunghwan; Fang, Dufei; Hsiao, Benjamin S; Chu, Benjamin

2005-10-01

A novel high flux filtration medium, consisting of a three-tier composite structure, i.e., a nonporous hydrophilic nanocomposite coating top layer, an electrospun nanofibrous substrate midlayer, and a conventional nonwoven microfibrous support, was demonstrated for oil/water emulsion separations for the first time. The nanofibrous substrate was prepared by electrospinning of poly(vinyl alcohol) (PVA) followed by chemical cross-linking with glutaraldehyde (GA) in acetone. The resulting cross-linked PVA substrates showed excellent water resistance and good mechanical properties. The top coating was based on a nanocomposite layer containing hydrophilic polyether-b-polyamide copolymer or a cross-linked PVA hydrogel incorporated with surface-oxidized multiwalled carbon nanotubes (MWNTs). Scanning electron microscopy (SEM) examinations indicated that the nanocomposite layer was nonporous within the instrumental resolution and MWNTs were well dispersed in the polymer matrix. Oil/ water emulsion tests showed that this unique type of filtration media exhibited a high flux rate (up to 330 L/m2-h at the feed pressure of 100 psi) and an excellent total organic solute rejection rate (99.8%) without appreciable fouling. The increase in the concentration of surface-oxidized MWNT in the coating layer generally improves the flux rate, which can be attributed to the generation of more effective hydrophilic nanochannels for water passage in the composite membranes.

Renal handling of sodium and water in the hypothyroid rat

PubMed Central

Michael, Ulrich F.; Barenberg, Robert L.; Chavez, Rafaelita; Vaamonde, Carlos A.; Papper, Solomon

1972-01-01

Hypothyroid rats were examined with conventional renal clearance and micropuncture techniques to elicit the mechanism and site within the nephron responsible for the increased salt and water excretion observed in these animals. When compared with age-matched control rats, a decrease in inulin clearance of 30% (P < 0.001) and in Hippuran clearance of 32% (P < 0.005) was observed in the hypothyroid rats. Absolute excretion of sodium and water was increased 3-fold (P < 0.02) and 2-fold (P < 0.025), respectively, while fractional excretion of sodium and water was increased 4.3-fold (P < 0.02) and 2.9-fold (P < 0.05), respectively, in the hypothyroid animals. Fractional proximal reabsorption of sodium as assessed from proximal tubular fluid to plasma ratios of inulin ([TF/P]IN) was found to be decreased by 28% (P < 0.001) in the hypothyroid rats. Superficial single nephron filtration rate was reduced proportionately to the decrease in total filtration rate in the hypothyroid rats. These data indicate that the proximal tubule is one of the sites of diminished sodium and water reabsorption in the hypothyroid rat. The data also suggest that the observed decrease in glomerular filtration rate in the hypothyroid animals is not caused by a decrease in the number of functioning nephrons and that the observed increase in sodium and water excretion is not caused by a redistribution of filtrate from juxtamedullary to superficial nephrons. Although the exact mechanisms of the observed changes in proximal tubular function remain unknown, the data suggest that they are probably related to the lack of thyroid hormone. Whatever their mechanism, it appears that the enhanced sodium and water excretion observed in the hypothyroid animals must be determined by further reduction in tubular sodium reabsorption in the distal nephron. PMID:5024038

Kidney-inspired algorithm for optimization problems

NASA Astrophysics Data System (ADS)

Jaddi, Najmeh Sadat; Alvankarian, Jafar; Abdullah, Salwani

2017-01-01

In this paper, a population-based algorithm inspired by the kidney process in the human body is proposed. In this algorithm the solutions are filtered in a rate that is calculated based on the mean of objective functions of all solutions in the current population of each iteration. The filtered solutions as the better solutions are moved to filtered blood and the rest are transferred to waste representing the worse solutions. This is a simulation of the glomerular filtration process in the kidney. The waste solutions are reconsidered in the iterations if after applying a defined movement operator they satisfy the filtration rate, otherwise it is expelled from the waste solutions, simulating the reabsorption and excretion functions of the kidney. In addition, a solution assigned as better solution is secreted if it is not better than the worst solutions simulating the secreting process of blood in the kidney. After placement of all the solutions in the population, the best of them is ranked, the waste and filtered blood are merged to become a new population and the filtration rate is updated. Filtration provides the required exploitation while generating a new solution and reabsorption gives the necessary exploration for the algorithm. The algorithm is assessed by applying it on eight well-known benchmark test functions and compares the results with other algorithms in the literature. The performance of the proposed algorithm is better on seven out of eight test functions when it is compared with the most recent researches in literature. The proposed kidney-inspired algorithm is able to find the global optimum with less function evaluations on six out of eight test functions. A statistical analysis further confirms the ability of this algorithm to produce good-quality results.

Rate of Decline in Serum PFOA Concentrations after Granular Activated Carbon Filtration at Two Public Water Systems in Ohio and West Virginia

PubMed Central

Bartell, Scott M.; Calafat, Antonia M.; Lyu, Christopher; Kato, Kayoko; Ryan, P. Barry; Steenland, Kyle

2010-01-01

Background Drinking water in multiple water districts in the Mid-Ohio Valley has been contaminated with perfluorooctanoic acid (PFOA), which was released by a nearby DuPont chemical plant. Two highly contaminated water districts began granular activated carbon filtration in 2007. Objectives To determine the rate of decline in serum PFOA, and its corresponding half-life, during the first year after filtration. Methods Up to six blood samples were collected from each of 200 participants from May 2007 until August 2008. The primary source of drinking water varied over time for some participants; our analyses were grouped according to water source at baseline in May–June 2007. Results For Lubeck Public Service District customers, the average decrease in serum PFOA concentrations between May–June 2007 and May–August 2008 was 32 ng/mL (26%) for those primarily consuming public water at home (n = 130), and 16 ng/mL (28%) for those primarily consuming bottled water at home (n = 17). For Little Hocking Water Association customers, the average decrease in serum PFOA concentrations between November–December 2007 and May–June 2008 was 39 ng/mL (11%) for consumers of public water (n = 39) and 28 ng/mL (20%) for consumers of bottled water (n = 11). The covariate-adjusted average rate of decrease in serum PFOA concentration after water filtration was 26% per year (95% confidence interval, 25–28% per year). Conclusions The observed data are consistent with first-order elimination and a median serum PFOA half-life of 2.3 years. Ongoing follow-up will lead to improved half-life estimation. PMID:20123620

Identification and characterization of kidney transplants with good glomerular filtration rate at 1 year but subsequent progressive loss of renal function.

PubMed

Park, Walter D; Larson, Timothy S; Griffin, Matthew D; Stegall, Mark D

2012-11-15

After the first year after kidney transplantation, 3% to 5% of grafts fail each year but detailed studies of how grafts progress to failure are lacking. This study aimed to analyze the functional stability of kidney transplants between 1 and 5 years after transplantation and to identify initially well-functioning grafts with progressive decline in allograft function. The study included 788 adult conventional kidney transplants performed at the Mayo Clinic Rochester between January 2000 and December 2005 with a minimum graft survival and follow-up of 2.6 years. The modification of diet in renal disease equation for estimating glomerular filtration rate (eGFR(MDRD)) was used to calculate the slope of renal function over time using all available serum creatinine values between 1 and 5 years after transplantation. Most transplants demonstrated good function (eGFR(MDRD) ≥40 mL/min) at 1 year with positive eGFR(MDRD) slope between 1 and 5 years after transplantation. However, a subset of grafts with 1-year eGFR(MDRD) ≥40 mL/min exhibited strongly negative eGFR(MDRD) slope between 1 and 5 years suggestive of progressive loss of graft function. Forty-one percent of this subset reached graft failure during follow-up, accounting for 69% of allograft failures occurring after 2.5 years after transplantation. This pattern of progressive decline in estimated glomerular filtration rate despite good early function was associated with but not fully attributable to factors suggestive of enhanced antidonor immunity. Longitudinal analysis of serial estimated glomerular filtration ratemeasurements identifies initially well-functioning kidney transplants at high risk for subsequent graft loss. For this subset, further studies are needed to identify modifiable causes of functional decline.

Resistant Hypertension, Time-Updated Blood Pressure Values and Renal Outcome in Type 2 Diabetes Mellitus.

PubMed

Viazzi, Francesca; Piscitelli, Pamela; Ceriello, Antonio; Fioretto, Paola; Giorda, Carlo; Guida, Pietro; Russo, Giuseppina; De Cosmo, Salvatore; Pontremoli, Roberto

2017-09-22

Apparent treatment resistant hypertension (aTRH) is highly prevalent in patients with type 2 diabetes mellitus (T2D) and entails worse cardiovascular prognosis. The impact of aTRH and long-term achievement of recommended blood pressure (BP) values on renal outcome remains largely unknown. We assessed the role of aTRH and BP on the development of chronic kidney disease in patients with T2D and hypertension in real-life clinical practice. Clinical records from a total of 29 923 patients with T2D and hypertension, with normal baseline estimated glomerular filtration rate and regular visits during a 4-year follow-up, were retrieved and analyzed. The association between time-updated BP control (ie, 75% of visits with BP <140/90 mm Hg) and the occurrence of estimated glomerular filtration rate <60 and/or a reduction ≥30% from baseline was assessed. At baseline, 17% of patients had aTRH. Over the 4-year follow-up, 19% developed low estimated glomerular filtration rate and 12% an estimated glomerular filtration rate reduction ≥30% from baseline. Patients with aTRH showed an increased risk of developing both renal outcomes (adjusted odds ratio, 1.31 and 1.43; P <0.001 respectively), as compared with those with non-aTRH. No association was found between BP control and renal outcomes in non-aTRH, whereas in aTRH, BP control was associated with a 30% ( P =0.036) greater risk of developing the renal end points. ATRH entails a worse renal prognosis in T2D with hypertension. BP control is not associated with a more-favorable renal outcome in aTRH. The relationship between time-updated BP and renal function seems to be J-shaped, with optimal systolic BP values between 120 and 140 mm Hg. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Estimated glomerular filtration rate is an early biomarker of cardiac surgery-associated acute kidney injury.

PubMed

Candela-Toha, Ángel; Pardo, María Carmen; Pérez, Teresa; Muriel, Alfonso; Zamora, Javier

2018-04-20

and objective Acute kidney injury (AKI) diagnosis is still based on serum creatinine and diuresis. However, increases in creatinine are typically delayed 48h or longer after injury. Our aim was to determine the utility of routine postoperative renal function blood tests, to predict AKI one or 2days in advance in a cohort of cardiac surgery patients. Using a prospective database, we selected a sample of patients who had undergone major cardiac surgery between January 2002 and December 2013. The ability of the parameters to predict AKI was based on Acute Kidney Injury Network serum creatinine criteria. A cohort of 3,962 cases was divided into 2groups of similar size, one being exploratory and the other a validation sample. The exploratory group was used to show primary objectives and the validation group to confirm results. The ability to predict AKI of several kidney function parameters measured in routine postoperative blood tests, was measured with time-dependent ROC curves. The primary endpoint was time from measurement to AKI diagnosis. AKI developed in 610 (30.8%) and 623 (31.4%) patients in the exploratory and validation samples, respectively. Estimated glomerular filtration rate using the MDRD-4 equation showed the best AKI prediction capacity, with values for the AUC ROC curves between 0.700 and 0.946. We obtained different cut-off values for estimated glomerular filtration rate depending on the degree of AKI severity and on the time elapsed between surgery and parameter measurement. Results were confirmed in the validation sample. Postoperative estimated glomerular filtration rate using the MDRD-4 equation showed good ability to predict AKI following cardiac surgery one or 2days in advance. Copyright © 2018 Sociedad Española de Nefrología. Published by Elsevier España, S.L.U. All rights reserved.

Urinary albumin excretion is associated with nocturnal systolic blood pressure in resistant hypertensives.

PubMed

Oliveras, Anna; Armario, Pedro; Martell-Clarós, Nieves; Ruilope, Luis M; de la Sierra, Alejandro

2011-03-01

Microalbuminuria is a known marker of subclinical organ damage. Its prevalence is higher in patients with resistant hypertension than in subjects with blood pressure at goal. On the other hand, some patients with apparently well-controlled hypertension still have microalbuminuria. The current study aimed to determine the relationship between microalbuminuria and both office and 24-hour ambulatory blood pressure. A cohort of 356 patients (mean age 64 ± 11 years; 40.2% females) with resistant hypertension (blood pressure ≥ 140 and/or 90 mm Hg despite treatment with ≥ 3 drugs, diuretic included) were selected from Spanish hypertension units. Patients with estimated glomerular filtration rate <30 mL/min/1.73 m(2) were excluded. All patients underwent clinical and demographic evaluation, complete laboratory analyses, and good technical-quality 24-hour ambulatory blood pressure monitoring. Urinary albumin/creatinine ratio was averaged from 3 first-morning void urine samples. Microalbuminuria (urinary albumin/creatinine ratio ≥ 2.5 mg/mmol in males or ≥ 3.5 mg/mmol in females) was detected in 46.6%, and impaired renal function (estimated glomerular filtration rate <60 mL/min/1.73 m(2)) was detected in 26.8%. Bivariate analyses showed significant associations of microalbuminuria with older age, reduced estimated glomerular filtration rate, increased nighttime systolic blood pressure, and elevated daytime, nighttime, and 24-hour diastolic blood pressure. In a logistic regression analysis, after age and sex adjustment, elevated nighttime systolic blood pressure (multivariate odds ratio, 1.014 [95% CI, 1.001 to 1.026]; P=0.029) and reduced estimated glomerular filtration rate (multivariate odds ratio, 2.79 [95% CI, 1.57 to 4.96]; P=0.0005) were independently associated with the presence of microalbuminuria. We conclude that microalbuminuria is better associated with increased nighttime systolic blood pressure than with any other office and 24-hour ambulatory blood pressure monitoring parameters.

Role of humoral mediators in, and influence of a liposomal formulation on, acute amphotericin B nephrotoxicity.

PubMed

Sabra, R; Zeinoun, N; Sharaf, L H; Ghali, R; Beshara, G; Serhal, H

2001-04-01

The mechanisms responsible for amphotericin B nephrotoxicity remain incompletely understood, but clearly involve reduction in renal blood flow and glomerular filtration rate. Both direct effects of amphotericin B on contractile vascular cells, and indirect effects, due to humoural mediators, have been proposed. This study examines the role of nitric oxide, endothelin and angiotensin II in the acute nephrotoxic effects of amphotericin B in rats, and compares the anti-fungal and nephrotoxic effects of liposomal amphotericin B and amphotericin B-deoxycholate. Anaesthetized rats were given infusions of amphotericin B-deoxycholate in the presence or absence of N-nitro-L-arginine, PD 145065, a non-specific endothelin receptor antagonist, and L-158809, an angiotensin II type I receptor antagonist, or increasing doses of liposomal amphotericin B. Amphotericin B-deoxycholate (0.03 mg/kg/min intravenously) caused a significant 44% reduction in glomerular filtration rate and 65% maximal fall in renal blood flow. N-Nitro-L-arginine-treated rats had a lower renal blood flow and glomerular filtration rate at baseline, but sustained similar reduction of 53% and 75% in these parameters, respectively. PD145065 and L-158809 did not modify these effects either. Increasing doses of liposomal amphotericin B (from 0.01 up to 0.50 mg/kg/min.) induced no change in either glomerular filtration rate or renal blood flow. In vitro susceptibility tests revealed similar potency for liposomal amphotericin B and amphotericin B-deoxycholate in their fungistatic effects and slightly higher potency for amphotericin B-deoxycholate in their fungicidal effect. These results suggest that endogenous endothelin, angiotensin II or nitric oxide systems are not involved in the nephrotoxic effects of amphotericin B. The liposomal amphotericin B results suggest that amphotericin B nephrotoxicity is due to a direct interaction of amphotericin B with renal cells that is prevented by its encapsulation in liposomes.

Improving precision of glomerular filtration rate estimating model by ensemble learning.

PubMed

Liu, Xun; Li, Ningshan; Lv, Linsheng; Fu, Yongmei; Cheng, Cailian; Wang, Caixia; Ye, Yuqiu; Li, Shaomin; Lou, Tanqi

2017-11-09

Accurate assessment of kidney function is clinically important, but estimates of glomerular filtration rate (GFR) by regression are imprecise. We hypothesized that ensemble learning could improve precision. A total of 1419 participants were enrolled, with 1002 in the development dataset and 417 in the external validation dataset. GFR was independently estimated from age, sex and serum creatinine using an artificial neural network (ANN), support vector machine (SVM), regression, and ensemble learning. GFR was measured by 99mTc-DTPA renal dynamic imaging calibrated with dual plasma sample 99mTc-DTPA GFR. Mean measured GFRs were 70.0 ml/min/1.73 m 2 in the developmental and 53.4 ml/min/1.73 m 2 in the external validation cohorts. In the external validation cohort, precision was better in the ensemble model of the ANN, SVM and regression equation (IQR = 13.5 ml/min/1.73 m 2 ) than in the new regression model (IQR = 14.0 ml/min/1.73 m 2 , P < 0.001). The precision of ensemble learning was the best of the three models, but the models had similar bias and accuracy. The median difference ranged from 2.3 to 3.7 ml/min/1.73 m 2 , 30% accuracy ranged from 73.1 to 76.0%, and P was > 0.05 for all comparisons of the new regression equation and the other new models. An ensemble learning model including three variables, the average ANN, SVM, and regression equation values, was more precise than the new regression model. A more complex ensemble learning strategy may further improve GFR estimates.

Modelling the removal of p-TSA (para-toluenesulfonamide) during rapid sand filtration used for drinking water treatment.

PubMed

Meffe, Raffaella; Kohfahl, Claus; Holzbecher, Ekkehard; Massmann, Gudrun; Richter, Doreen; Dünnbier, Uwe; Pekdeger, Asaf

2010-01-01

A finite element model was set-up to determine degradation rate constants for p-TSA during rapid sand filtration (RSF). Data used for the model originated from a column experiment carried out in the filter hall of a drinking water treatment plant in Berlin (Germany). Aerated abstracted groundwater was passed through a 1.6m long column-shaped experimental sand filter applying infiltration rates from 2 to 6mh(-1). Model results were fitted to measured profiles and breakthrough curves of p-TSA for different infiltration rates using both first-order reaction kinetics and Michaelis-Menten kinetics. Both approaches showed that degradation rates varied both in space and time. Higher degradation rates were observed in the upper part of the column, probably related to higher microbial activity in this zone. Measured and simulated breakthrough curves revealed an adaption phase with lower degradation rates after infiltration rates were changed, followed by an adapted phase with more elevated degradation rates. Irrespective of the mathematical approach and the infiltration rate, degradation rates were very high, probably owing to the fact that filter sands have been in operation for decades, receiving high p-TSA concentrations with the raw water.

Case studies for utilizing groundwater-source and low-enthalpy geothermal resources in Korea

NASA Astrophysics Data System (ADS)

Kim, K.-H.; Shin, J.; Lee, K.-K.; Lee, T. J.

2012-04-01

As one of the top 10 oil-consuming countries in the world, Korea recently has had a great interest in extending the ways to utilize renewable energy. In this regard, geothermal energy resource is attracting more concerns from both of the government and the research field. Korea has neither active volcanic sites nor areas with abnormally higher heat flow. In spite of these natural conditions, many efforts have been exerted to utilize geothermal energy. Here, we introduce two case studies of using groundwater-source geothermal energy with relatively low-enthalpy: One is a riverbank filtration facility, which has been using some of its riverbank filtrate water for the indoor air-conditioning. The other is the first EGS plant planning site, where a few fault-related artesian wells reaching 70C were discovered lately. Numerical simulations to predict the temperature evolution of the two sites, which is dominated by several hydrogeologic factors, were carried out and compared. Simulation of temperature profile of riverbank filtrate water using HydroGeoSphere shows that the primary factor in determining filtrate water temperature is the pumping rate. It also shows that maintaining the facility operation with present pumping rate for the next 30 years will not cause any significant change of water temperature. However, following the new plan of the facility to install additional 37 wells with 6 times higher pumping rate than the current rate might cause about 2C decrease in filtrate water temperature in 10 years after the extension. Simulation for the temperature evolution in a faulted geothermal reservoir in EGS planning site under the supposed injection-extraction operating conditions were carried out using TOUGH2. A MINC model including a hydraulic discontinuity, which reflected the analysis from several geophysical explorations, was generated. Temperature distribution calculated from the simulation shows a rise of relatively hot geothermal water along the fault plane. It was proven out that in order to secure a stable operating efficiency of the plant, distance between the wells should be kept far enough so that the injected cold water can be warmed along the underground flow path. And after the installation of the wells, pumping/injection rates should be controlled carefully to adjust the underground fluid velocity in faulted geothermal reservoir and to avoid excessive drawdown. Acknowledgement: This study is financially supported by an R&D program from KICTEP for the "Advanced Technology for Groundwater Development and Application in Riverside Region".

High-NaCl diet impairs dynamic renal blood flow autoregulation in rats with adenine-induced chronic renal failure.

PubMed

Saeed, Aso; DiBona, Gerald F; Grimberg, Elisabeth; Nguy, Lisa; Mikkelsen, Minne Line Nedergaard; Marcussen, Niels; Guron, Gregor

2014-03-15

This study examined the effects of 2 wk of high-NaCl diet on kidney function and dynamic renal blood flow autoregulation (RBFA) in rats with adenine-induced chronic renal failure (ACRF). Male Sprague-Dawley rats received either chow containing adenine or were pair-fed an identical diet without adenine (controls). After 10 wk, rats were randomized to either remain on the same diet (0.6% NaCl) or to be switched to high 4% NaCl chow. Two weeks after randomization, renal clearance experiments were performed under isoflurane anesthesia and dynamic RBFA, baroreflex sensitivity (BRS), systolic arterial pressure variability (SAPV), and heart rate variability were assessed by spectral analytical techniques. Rats with ACRF showed marked reductions in glomerular filtration rate and renal blood flow (RBF), whereas mean arterial pressure and SAPV were significantly elevated. In addition, spontaneous BRS was reduced by ∼50% in ACRF animals. High-NaCl diet significantly increased transfer function fractional gain values between arterial pressure and RBF in the frequency range of the myogenic response (0.06-0.09 Hz) only in ACRF animals (0.3 ± 4.0 vs. -4.4 ± 3.8 dB; P < 0.05). Similarly, a high-NaCl diet significantly increased SAPV in the low-frequency range only in ACRF animals. To conclude, a 2-wk period of a high-NaCl diet in ACRF rats significantly impaired dynamic RBFA in the frequency range of the myogenic response and increased SAPV in the low-frequency range. These abnormalities may increase the susceptibility to hypertensive end-organ injury and progressive renal failure by facilitating pressure transmission to the microvasculature.

Cardiorespiratory responses of air filtration: A randomized crossover intervention trial in seniors living in Beijing: Beijing Indoor Air Purifier StudY, BIAPSY.

PubMed

Shao, Danqing; Du, Yipeng; Liu, Shuo; Brunekreef, Bert; Meliefste, Kees; Zhao, Qian; Chen, Jie; Song, Xiaoming; Wang, Meng; Wang, Juan; Xu, Hongbing; Wu, Rongshan; Wang, Tong; Feng, Baihuan; Lung, Candice Shih-Chun; Wang, Xian; He, Bei; Huang, Wei

2017-12-15

In this Beijing Indoor Air Purifier StudY (BIAPSY), we conducted a randomized crossover intervention trial in a panel of 35 non-smoking senior participants with free-living, with and without chronic obstructive pulmonary disease (COPD). Portable air filtration units were randomly allocated to active-(filter in) for 2weeks and sham-mode (filter out) for 2weeks in the households. We examined the differences in indoor air pollutant concentrations in 20 study homes and a suite of cardio-respiratory biomarker levels in study participants between filtration modes, with and without adjustment for potential confounders. Following active filtration, we observed significant reductions from 60±45 to 24±15μg/m 3 in ten-day averages of indoor PM 2.5 and reductions from 3.87±1.65 to 1.81±1.19m -1 .10 -5 in ten-day averages of indoor BC, compared to sham-mode filtration. The major components of indoor PM 2.5 , including water soluble organics, NO 3 - , SO 4 2- , Zn 2+ , Pb 2+ and K + , were also reduced significantly by 42% to 63%. However, following active filtration, we only observed significant reductions on systemic inflammation measured as of IL-8 at 58.59% (95% CI: -76.31, -27.64) in the total group of participants and 70.04% (95% CI: -83.05, -47.05) in the subset of COPD patients, with adjustments. We were not able to detect improvements on lung function, blood pressure, and heart rate variability, following short-term intervention of two-week active air filtration. In conclusion, our results showed that indoor air filtration produced clear improvement on indoor air quality, but no demonstrable changes in the cardio-respiratory outcomes of study interest observed in the seniors living with real-world air pollution exposures. Copyright © 2017 Elsevier B.V. All rights reserved.

Nanocarbon-based membrane filtration integrated with electric field driving for effective membrane fouling mitigation.

PubMed

Fan, Xinfei; Zhao, Huimin; Quan, Xie; Liu, Yanming; Chen, Shuo

2016-01-01

Membrane filtration provides an effective solution for removing pollutants from water but is limited by serious membrane fouling. In this work, an effective approach was used to mitigate membrane fouling by integrating membrane filtration with electropolarization using an electroconductive nanocarbon-based membrane. The electropolarized membrane (EM) by alternating square-wave potentials between +1.0 V and -1.0 V with a pulse width of 60 s exhibited a permeate flux 8.1 times as high as that without electropolarization for filtering feed water containing bacteria, which confirms the ability of the EM to achieve biofouling mitigation. Moreover, the permeate flux of EM was 1.5 times as high as that without electropolarization when filtrating natural organic matter (NOM) from water, and demonstrated good performance in organic fouling mitigation with EM. Furthermore, the EM was also effective for complex fouling mitigation in filtering water containing coexisting bacteria and NOM, and presented an increased flux rate 1.9 times as high as that without electropolarization. The superior fouling mitigation performance of EM was attributed to the synergistic effects of electrostatic repulsion, electrochemical oxidation and electrokinetic behaviors. This work opens an effective avenue for membrane fouling mitigation of water-treatment membrane filtration systems. Copyright © 2015 Elsevier Ltd. All rights reserved.

Design parameters for rotating cylindrical filtration

NASA Technical Reports Server (NTRS)

Schwille, John A.; Mitra, Deepanjan; Lueptow, Richard M.

2002-01-01

Rotating cylindrical filtration displays significantly reduced plugging of filter pores and build-up of a cake layer, but the number and range of parameters that can be adjusted complicates the design of these devices. Twelve individual parameters were investigated experimentally by measuring the build-up of particles on the rotating cylindrical filter after a fixed time of operation. The build-up of particles on the filter depends on the rotational speed, the radial filtrate flow, the particle size and the gap width. Other parameters, such as suspension concentration and total flow rate are less important. Of the four mechanisms present in rotating filters to reduce pore plugging and cake build-up, axial shear, rotational shear, centrifugal sedimentation and vortical motion, the evidence suggests rotational shear is the dominant mechanism, although the other mechanisms still play minor roles. The ratio of the shear force acting parallel to the filter surface on a particle to the Stokes drag acting normal to the filter surface on the particle due to the difference between particle motion and filtrate flow can be used as a non-dimensional parameter that predicts the degree of particle build-up on the filter surface for a wide variety of filtration conditions. c2002 Elsevier Science B.V. All rights reserved.

Carbon and Nitrogen Accumulation Rates in Salt Marshes in Oregon, USA

EPA Science Inventory

Two important ecosystem services of wetlands are carbon sequestration and filtration of nutrients and particulates. We quantified the carbon and nitrogen accumulation rates in salt marshes at 135 plots distributed across eight estuaries located in Oregon, USA. Net carbon and ...

Mechanisms of chronic waterborne Zn toxicity in Daphnia magna.

PubMed

Muyssen, Brita T A; De Schamphelaere, Karel A C; Janssen, Colin R

2006-05-25

In order to gain better insights in the integrated response of Daphnia magna following chronic zinc exposure, several physiological parameters were measured in a time-dependent manner. D. magna juveniles were exposed for 21 days to dissolved Zn concentrations up to 340 microg/L. Next to standard endpoints such as mortality, growth and reproduction the following sub-lethal endpoints were measured: filtration and ingestion rate, respiration rate, energy reserves, internal Zn and total Ca concentrations in the organisms. Organisms exposed to 80 microg/L generally performed better than the Zn deprived control organisms. The former were used to elucidate the effects of higher Zn concentrations on the endpoints mentioned above. After 1 week, only 7% of the organisms exposed to 340 microg/L survived. Body Zn contents of these organisms were 281 +/- 76 microg g dry weight and a 37% decrease of the Ca contents was observed. This suggests a competitive effect of Zn on Ca uptake. Filtration rate (-51%), individual weight (-58%) and energy reserves (-35%) also exhibited a decreasing trend as a function of increasing Zn exposure concentrations. During the second and third exposure week an overall repair process was observed. In the surviving organisms mortality and reproduction were only slightly affected. This can be explained by (over)compensation reactions at lower levels of biological organisation: Ca contents (+24%) and filtration rate (+90%) increased as a function of the exposure concentration while respiration rate decreased (-29%) resulting in energy reserves remaining constant as a function of Zn exposure. It is hypothesized that a disturbed Ca balance is probably the first cause for zinc toxicity effects in D. magna.

Hyperkalemia After Initiating Renin-Angiotensin System Blockade: The Stockholm Creatinine Measurements (SCREAM) Project.

PubMed

Bandak, Ghassan; Sang, Yingying; Gasparini, Alessandro; Chang, Alex R; Ballew, Shoshana H; Evans, Marie; Arnlov, Johan; Lund, Lars H; Inker, Lesley A; Coresh, Josef; Carrero, Juan-Jesus; Grams, Morgan E

2017-07-19

Concerns about hyperkalemia limit the use of angiotensin-converting enzyme inhibitors (ACE-I) and angiotensin receptor blockers (ARBs), but guidelines conflict regarding potassium-monitoring protocols. We quantified hyperkalemia monitoring and risks after ACE-I/ARB initiation and developed and validated a hyperkalemia susceptibility score. We evaluated 69 426 new users of ACE-I/ARB therapy in the Stockholm Creatinine Measurements (SCREAM) project with medication initiation from January 1, 2007 to December 31, 2010, and follow-up for 1 year thereafter. Three fourths (76%) of SCREAM patients had potassium checked within the first year. Potassium >5 and >5.5 mmol/L occurred in 5.6% and 1.7%, respectively. As a comparison, we propensity-matched new ACE-I/ARB users to 20 186 new β-blocker users in SCREAM: 64% had potassium checked. The occurrence of elevated potassium levels was similar between new β-blocker and ACE-I/ARB users without kidney disease; only at estimated glomerular filtration rate <60 mL/min per 1.73 m 2 were risks higher among ACE-I/ARB users. We developed a hyperkalemia susceptibility score that incorporated estimated glomerular filtration rate, baseline potassium level, sex, diabetes mellitus, heart failure, and the concomitant use of potassium-sparing diuretics in new ACE-I/ARB users; this score accurately predicted 1-year hyperkalemia risk in the SCREAM cohort (area under the curve, 0.845, 95% CI: 0.840-0.869) and in a validation cohort from the US-based Geisinger Health System (N=19 524; area under the curve, 0.818, 95% CI: 0.794-0.841), with good calibration. Hyperkalemia within the first year of ACE-I/ARB therapy was relatively uncommon among people with estimated glomerular filtration rate >60 mL/min per 1.73 m 2 , but rates were much higher with lower estimated glomerular filtration rate. Use of the hyperkalemia susceptibility score may help guide laboratory monitoring and prescribing strategies. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Determination of the glomerular filtration rate (GFR): methodological problems, age-dependence, consequences of various surgical interventions, and the influence of different drugs and toxic substances.

PubMed

Fleck, C

1999-01-01

Determinations of renal clearance of fluorescein isothiocyanate (FITC)-inulin were used for assessing the glomerular filtration rate (GFR) in rats and to characterize factors influencing the glomerular filtration capacity. In anesthetized rats, GFR develops after birth up to day 30. Thereafter, GFR remains relatively constant for up to 3 months of age and drops continuously until the 8th month. GFR can be determined in utero, already one day before birth, however, only at a very low level. It increases significantly on the first day of life. Even at this time the effect of furosemide on GFR can be proven. After reduction of renal mass, GFR is decreased in dependence on the extent of kidney tissue removal. However, within 2 days after unilateral nephrectomy (NX) or one week after 5/6 NX, GFR reaches values about 3/4 of the controls with two intact kidneys. Furthermore, the compensation of GFR after renal ischemia reaches 80% of baseline values after one week. On the other hand, GFR is enhanced after bile duct ligation as a model of hepato-renal failure. It has been shown in previous experiments that pretreatment with hormones can stimulate renal tubular transport processes. Pretreatment with dexamethasone or triiodothyronine after 5/6 NX improves glomerular filtration capacity whereas in animals with ligated bile ducts dexamethasone seems to prevent the increase in GFR. After subchronic treatment with epidermal growth factor (EGF) GFR is significantly reduced. A continuous infusion of amino acids does not change GFR in the controls but enhances the filtration capacity in EGF-treated rats. But immediately after bolus injection of amino acids GFR also increases significantly in the controls. Diuretics such as furosemide, most nephrotoxic agents (cyclosporine A [CsA], heavy metals) and imidazole reduce the GFR significantly. Diltiazem reported to act nephroprotectively in CsA nephrotoxicity in human beings was without beneficial effect in rats. This could be due to species differences in GFR because the rat is one of the species with the highest glomerular filtration capacity.

Enhanced renal prostaglandin production in the dog. I. Effects on renal function.

PubMed

Tannenbaum, J; Splawinski, J A; Oates, J A; Nies, A S

1975-01-01

The changes in renal function produced by endogenous synthesis of prostaglandins by the kidney were evaluated by infusing sodium arachidonate, the prescursor of the prostaglandins, into one renal artery of the dog. These changes were compared with those produced by similar infusions on performed prostaglandin (PG) E2 and F2alpha.PGE2given at 0.01-0.3 mug/kg min--1 produced dose-related increases in urine flow, sodium and potassium excretion, free water clearance, and renal blood flow. The glomerular filtration rage increased only at the lowest dose and the calculated filtration fraction fell. Arachidonic acid at 1.0-30.0 mug/kg min--1 similarly produced dose-related increases in electrolyte excretion, but the increase in renal blood flow was much less than that produced by PGE2 and there were no changes in glomerular filtration rate, filtration fraction, or free water clearances. PGF2alpha had essentially no effects at infusion rates of 0.03-1.0 mug/kg min--1. All renal effects of arachidonic acid were inhibited by simultaneous infusions of an inhibitor of prostaglandin synthetase, 5, 8, 11,14-eicosatetraynoic acid (20:4). None of the effects produced by PGE2 were inhibited by 20:4. These results indicate that enhanced endogenous renal prostaglandin synthesis, which can be produced by arachidonate infusion, results in significant alterations of renal function. This finding strengthens the hypothesis that renal prostaglandins formed in vivo have physiological importance as regulators of renal function.

High sodium intake increases blood pressure and alters renal function in intrauterine growth-retarded rats.

PubMed

Sanders, Marijke W; Fazzi, Gregorio E; Janssen, Ger M J; Blanco, Carlos E; De Mey, Jo G R

2005-07-01

A suboptimal fetal environment increases the risk to develop cardiovascular disease in the adult. We reported previously that intrauterine stress in response to reduced uteroplacental blood flow in the pregnant rat limits fetal growth and compromises renal development, leading to an altered renal function in the adult offspring. Here we tested the hypothesis that high dietary sodium intake in rats with impaired renal development attributable to intrauterine stress, results in increased blood pressure, altered renal function, and organ damage. In rats, intrauterine stress was induced by bilateral ligation of the uterine arteries at day 17 of pregnancy. At the age of 12 weeks, the offspring was given high-sodium drinking water (2% sodium chloride). At the age of 16 weeks, rats were instrumented for monitoring of blood pressure and renal function. After intrauterine stress, litter size and birth weight were reduced, whereas hematocrit at birth was increased. Renal blood flow, glomerular filtration rate, and the glomerular filtration fraction were increased significantly after intrauterine stress. High sodium intake did not change renal function and blood pressure in control animals. However, during high sodium intake in intrauterine stress offspring, renal blood flow, glomerular filtration rate, and the filtration fraction were decreased, and blood pressure was increased. In addition, these animals developed severe albuminuria, an important sign of renal dysfunction. Thus, a suboptimal fetal microenvironment, which impairs renal development, results in sodium-dependent hypertension and albuminuria.

CROSSFLOW FILTRATON: LITERATURE REVIEW

DOE Office of Scientific and Technical Information (OSTI.GOV)

Duignan, M.

2011-01-01

As part of the Filtration task EM-31, WP-2.3.6, which is a joint effort between Savannah River National Laboratory (SRNL) and the Pacific Northwest National Laboratory (PNNL), tests were planned to evaluate crossflow filtration in order to the improve the use of existing hardware in the waste treatment plants at both the Department of Energy (DOE) Savannah River Site (SRS) and Hanford Site. These tests included experiments to try different operating conditions and additives, such as filter aids, in order to create a more permeable filter cake and improve the permeate flux. To plan the SRNL tests a literature review wasmore » performed to provide information on previous experiments performed by DOE laboratories, and by academia. This report compliments PNNL report (Daniel, et al 2010), and is an attempt to try and capture crossflow filtration work performed in the past that provide a basis for future testing. However, not all sources on crossflow filtration could be reviewed due to the shear volume of information available. In this report various references were examined and a representative group was chosen to present the major factors that affect crossflow filtration. The information summarized in this review contains previous operating conditions studied and their influence on the rate of filtration. Besides operating conditions, other attempted improvements include the use of filter aids, a pre-filtration leaching process, the backpulse system, and various types of filter tubes and filter coatings. The results from past research can be used as a starting point for further experimentation that can result in the improvement in the performance of the crossflow filtration. The literature reviewed in this report indicates how complex the crossflow issues are with the results of some studies appearing to conflict results from other studies. This complexity implies that filtration of mobilized stored waste cannot be explained in a simple generic sense; meaning an empirical model develop from one waste-filter combination will more than likely not be applicable to another combination. It appears that filtration performance varies as wide as the range of the types of slurry wastes that exist. However, conclusions can be elicited from existing information so that filter performance can be better understood, and hopefully improved. Those conclusions and recommendations for the planned tests are listed.« less

Student Perception of Competence and Attitude in Middle School Physical Education

ERIC Educational Resources Information Center

Scrabis-Fletcher, Kristin; Silverman, Stephen

2017-01-01

Motivation is a dynamic process that accounts for the interaction and filtration of information by the student and the effect that it has on student behavior. Perception of competence, an embedded motivational theory, posits that the influence of prior experience and information received from outside sources affects student behavior (Harter,…

Numerical model of two-dimensional heterogeneous combustion in porous media under natural convection or forced filtration

NASA Astrophysics Data System (ADS)

Lutsenko, Nickolay A.

2018-03-01

A novel mathematical model and original numerical method for investigating the two-dimensional waves of heterogeneous combustion in porous media are proposed and described in detail. The mathematical model is constructed within the framework of the model of interacting interpenetrating continua and includes equations of state, continuity, momentum conservation and energy for solid and gas phases. Combustion, considered in the paper, is due to the exothermic reaction between fuel in the porous solid medium and oxidiser contained in the gas flowing through the porous object. The original numerical method is based on a combination of explicit and implicit finite-difference schemes. A distinctive feature of the proposed model is that the gas velocity at the open boundaries (inlet and outlet) of the porous object is unknown and has to be found from the solution of the problem, i.e. the flow rate of the gas regulates itself. This approach allows processes to be modelled not only under forced filtration, but also under free convection, when there is no forced gas input in porous objects, which is typical for many natural or anthropogenic disasters (burning of peatlands, coal dumps, landfills, grain elevators). Some two-dimensional time-dependent problems of heterogeneous combustion in porous objects have been solved using the proposed numerical method. It is shown that two-dimensional waves of heterogeneous combustion in porous media can propagate in two modes with different characteristics, as in the case of one-dimensional combustion, but the combustion front can move in a complex manner, and gas dynamics within the porous objects can be complicated. When natural convection takes place, self-sustaining combustion waves can go through the all parts of the object regardless of where an ignition zone was located, so the all combustible material in each part of the object is burned out, in contrast to forced filtration.

Microbial community dynamics and biogas production from manure fractions in sludge bed anaerobic digestion.

PubMed

Nordgård, A S R; Bergland, W H; Bakke, R; Vadstein, O; Østgaard, K; Bakke, I

2015-12-01

To elucidate how granular sludge inoculum and particle-rich organic loading affect the structure of the microbial communities and process performance in upflow anaerobic sludge bed (UASB) reactors. We investigated four reactors run on dairy manure filtrate and four on pig manure supernatant for three months achieving similar methane yields. The reactors fed with less particle rich pig manure stabilized faster and had highest capacity. Microbial community dynamics analysed by a PCR/denaturing gradient gel electrophoresis approach showed that influent was a major determinant for the composition of the reactor communities. Comparisons of pre- and non-adapted inoculum in the reactors run on pig manure supernatant showed that the community structure of the nonadapted inoculum adapted in approximately two months. Microbiota variance partitioning analysis revealed that running time, organic loading rate and inoculum together explained 26 and 31% of the variance in bacterial and archaeal communities respectively. The microbial communities of UASBs adapted to the reactor conditions in treatment of particle rich manure fractions, obtaining high capacity, especially on pig manure supernatant. These findings provide relevant insight into the microbial community dynamics in startup and operation of sludge bed reactors for methane production from slurry fractions, a major potential source of biogas. © 2015 The Society for Applied Microbiology.

Automated in-line gel filtration for native state mass spectrometry.

PubMed

Waitt, Greg M; Xu, Robert; Wisely, G Bruce; Williams, Jon D

2008-02-01

Characterization of protein-ligand complexes by nondenaturing mass spectrometry provides direct evidence of drug-like molecules binding with potential therapeutic targets. Typically, protein-ligand complexes to be analyzed contain buffer salts, detergents, and other additives to enhance protein solubility, all of which make the sample unable to be analyzed directly by electrospray ionization mass spectrometry. This work describes an in-line gel-filtration method that has been automated and optimized. Automation was achieved using commercial HPLC equipment. Gel column parameters that were optimized include: column dimensions, flow rate, packing material type, particle size, and molecular weight cut-off. Under optimal conditions, desalted protein ions are detected 4 min after injection and the analysis is completed in 20 min. The gel column retains good performance even after >200 injections. A demonstration for using the in-line gel-filtration system is shown for monitoring the exchange of fatty acids from the pocket of a nuclear hormone receptor, peroxisome proliferator activator-delta (PPARdelta) with a tool compound. Additional utilities of in-line gel-filtration mass spectrometry system will also be discussed.

Transpulmonary passage of venous air emboli

NASA Technical Reports Server (NTRS)

Butler, B. D.; Hills, B. A.

1985-01-01

Twenty-seven paralyzed anesthetized dogs were embolized with venous air to determine the effectiveness of the pulmonary vasculature for bubble filtration or trapping. Air doses ranged from 0.05 to 0.40 ml/kg min in 0.05-ml increments with ultrasonic Doppler monitors placed over arterial vessels to detect any microbubbles that crossed the lungs. Pulmonary vascular filtration of the venous air infusions was complete for the lower air doses ranging from 0.05 to 0.30 ml/kg min. When the air doses were increased to 0.35 ml/kg min, the filtration threshold was exceeded with arterial spillover of bubbles occurring in 50 percent of the animals and reaching 71 percent for 0.40 ml/kg min. Significant elevations were observed in pulmonary arterial pressure and pulmonary vascular resistance. Systemic blood pressure and cardiac output decreased, whereas left ventricular end-diastolic pressure remained unchanged. The results indicate that the filtration of venous bubbles by the pulmonary vasculature was complete when the air infusion rates were kept below a threshold value of 0.30 ml/kg min.

Optimization of the cleaning process on a pilot filtration setup for waste water treatment accompanied by flow visualization

NASA Astrophysics Data System (ADS)

Bílek, Petr; Hrůza, Jakub

2018-06-01

This paper deals with an optimization of the cleaning process on a liquid flat-sheet filter accompanied by visualization of the inlet side of a filter. The cleaning process has a crucial impact on the hydrodynamic properties of flat-sheet filters. Cleaning methods avoid depositing of particles on the filter surface and forming a filtration cake. Visualization significantly helps to optimize the cleaning methods, because it brings new overall view on the filtration process in time. The optical method, described in the article, enables to see flow behaviour in a thin laser sheet on the inlet side of a tested filter during the cleaning process. Visualization is a strong tool for investigation of the processes on filters in details and it is also possible to determine concentration of particles after an image analysis. The impact of air flow rate, inverse pressure drop and duration on the cleaning mechanism is investigated in the article. Images of the cleaning process are compared to the hydrodynamic data. The tests are carried out on a pilot filtration setup for waste water treatment.

Cytokine filtration modulates pulmonary metabolism and edema formation during ex vivo lung perfusion.

PubMed

Iskender, Ilker; Cosgun, Tugba; Arni, Stephan; Trinkwitz, Michael; Fehlings, Stefan; Yamada, Yoshito; Cesarovic, Nikola; Yu, Keke; Frauenfelder, Thomas; Jungraithmayr, Wolfgang; Weder, Walter; Inci, Ilhan

2017-05-20

Ex vivo lung perfusion (EVLP) has improved the process of donor lung management. Cytokine accumulation during EVLP has been shown to correlate with worse outcome after lung transplantation. Our objective in this study was to test the safety and efficacy of cytokine filtration during EVLP in a large animal model. Pig donor lungs were preserved for 24 hours at 4°C, followed by 12 hours of EVLP, according to the Toronto protocol. The perfusate was continuously run through an absorbent device (CytoSorb) via a veno-venous shunt from the reservoir in the filter group. EVLP was performed according to the standard protocol in the control group (n = 5 each). EVLP physiology, lung X-ray, perfusate biochemistry, inflammatory response and microscopic injury were assessed. Cytokine filtration significantly improved airway pressure and dynamic compliance during the 12-hour perfusion period. Lung X-rays acquired at the end of perfusion showed increased consolidation in the control group. Electrolyte imbalance, determined by increased hydrogen, potassium and calcium ion concentrations in the perfusate, was markedly worsened in the control group. Glucose consumption and lactate production were markedly reduced, along with the lactate/pyruvate ratio in the filter group. Cytokine expression profile, tissue myeloperoxidase activity and microscopic lung injury were significantly reduced in the filter group. Continuous perfusate filtration through sorbent beads is effective and safe during prolonged EVLP. Cytokine removal decreased the development of pulmonary edema and electrolyte imbalance through the suppression of anaerobic glycolysis and neutrophil activation in this setting. Further studies are needed to test the beneficial effect of cytokine filtration on post-transplant lung function. Copyright © 2017 International Society for the Heart and Lung Transplantation. Published by Elsevier Inc. All rights reserved.

Combination of granular activated carbon adsorption and deep-bed filtration as a single advanced wastewater treatment step for organic micropollutant and phosphorus removal.

PubMed

Altmann, Johannes; Rehfeld, Daniel; Träder, Kai; Sperlich, Alexander; Jekel, Martin

2016-04-01

Adsorption onto granular activated carbon (GAC) is an established technology in water and advanced wastewater treatment for the removal of organic substances from the liquid phase. Besides adsorption, the removal of particulate matter by filtration and biodegradation of organic substances in GAC contactors has frequently been reported. The application of GAC as both adsorbent for organic micropollutant (OMP) removal and filter medium for solids retention in tertiary wastewater filtration represents an energy- and space saving option, but has rarely been considered because high dissolved organic carbon (DOC) and suspended solids concentrations in the influent of the GAC adsorber put a significant burden on this integrated treatment step and might result in frequent backwashing and unsatisfactory filtration efficiency. This pilot-scale study investigates the combination of GAC adsorption and deep-bed filtration with coagulation as a single advanced treatment step for simultaneous removal of OMPs and phosphorus from secondary effluent. GAC was assessed as upper filter layer in dual-media downflow filtration and as mono-media upflow filter with regard to filtration performance and OMP removal. Both filtration concepts effectively removed suspended solids and phosphorus, achieving effluent concentrations of 0.1 mg/L TP and 1 mg/L TSS, respectively. Analysis of grain size distribution and head loss within the filter bed showed that considerable head loss occurred in the topmost filter layer in downflow filtration, indicating that most particles do not penetrate deeply into the filter bed. Upflow filtration exhibited substantially lower head loss and effective utilization of the whole filter bed. Well-adsorbing OMPs (e.g. benzotriazole, carbamazepine) were removed by >80% up to throughputs of 8000-10,000 bed volumes (BV), whereas weakly to medium adsorbing OMPs (e.g. primidone, sulfamethoxazole) showed removals <80% at <5,000 BV. In addition, breakthrough behavior was also determined for gabapentin, an anticonvulsant drug recently detected in drinking water resources for which suitable removal technologies are still largely unknown. Gabapentin showed poor adsorptive removal, resulting in rapid concentration increases. Whereas previous studies classified gabapentin as not readily biodegradable, sustained removal was observed after prolonged operation and points at biological elimination of gabapentin within the GAC filter. The application of GAC as filter medium was compared to direct addition of powdered activated carbon (PAC) to deep-bed filtration as a direct process alternative. Both options yielded comparable OMP removals for most compounds at similar carbon usage rates, but GAC achieved considerably higher removals for biodegradable OMPs. Based on the results, the application of GAC in combination with coagulation/filtration represents a promising alternative to powdered activated carbon and ozone for advanced wastewater treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Removing micron size particles from coal liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rodgers, B.R.; Westmoreland, P.R.

This paper reports results of an investigation which was undertaken in order to improve purification of liquid fuels obtained by coal liquefaction processes. It is shown that settling and filtration rates increased substantially after agglomeration. And, ground coal was found to be an economical substitute for diatomaceous earth in filtration. The effects of certain solvents on the agglomerating tendencies of solids in the unfiltered oil (UFO) from the SRC and COED processes were determined by oil immersion microscopy. The significant results obtained by these experiments are listed. Economic advantages are presented. 13 references.

Wash water solids removal system study

NASA Technical Reports Server (NTRS)

1974-01-01

During wash water purification, surfactants tend to precipitate and foul the RO membranes, causing water flux decline and loss of salt rejection. The use of 165 to 190 ppm ferric chloride and optionally 0.25 to 1.0 ppm polymeric flocculate precipitates 92 to 96 percent of the surfactant from an Olive Leaf Soap based wash water. Crossflow filtration and pressure filtration yield good soap rejection at high water flux rates. Post-treatment of the chemically pretreated and filtered wash water with activated charcoal removes the residual soap down to an undetectable level.

Giant larvaceans: biologically equivalent flapping flexible foils exhibit bending modes that enhance fluid transport

NASA Astrophysics Data System (ADS)

Katija, Kakani; Sherman, Alana; Robison, Bruce

2016-11-01

The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet remains one of the least explored. Little-known marine organisms that inhabit midwater have developed life strategies that contribute to their evolutionary success, and may inspire engineering solutions for societally relevant challenges. A group of midwater organisms, known as giant larvaceans (genus Bathochordaeus), beat their tails to drive food and particle-laden water through complex, mucus filtering structures to feed. Giant larvaceans, whose motion and kinematics resemble flapping flexible foils, range in size from 1 to 10 cm in length, and can be found between the surface and 400 m. Using remotely-operated vehicles and DeepPIV, an instrument that enables in situ particle image velocimetry (PIV) measurements, the filtration rates and kinematics of giant larvaceans were investigated. These measurements yielded filtration rates for giant larvaceans as high as 80 L/hr, which exceeds expected filtration rates by a factor of 2 when compared with other larvacean groups. Comparing tail kinematics between Bathochordeaus and smaller larvaceans reveals differences in tail bending modes, where a hinge is present throughout the tail beat in giant larvaceans. Using laboratory PIV measurements with swimming animals and soft-bodied mechanical mimics, we reveal how these differences in tail kinematics can lead to enhanced fluid transport. This work has been supported by the Packard Foundation.

The Sonoma Water Evaluation Trial: A Randomized Drinking Water Intervention Trial to Reduce Gastrointestinal Illness in Older Adults

PubMed Central

Hilton, Joan F.; Wright, Catherine C.; Arnold, Benjamin F.; Saha, Sona; Wade, Timothy J.; Scott, James; Eisenberg, Joseph N.S.

2009-01-01

Objectives. We estimated the relative rate of highly credible gastrointestinal illness (HCGI) per year associated with active versus sham household water filtration devices among older adults in a community receiving tap water meeting current US standards. Methods. We conducted a randomized, triple-blinded, crossover trial in 714 households (988 individuals), which used active and sham water filtration devices for 6 months each. We estimated the annual incidence rate ratio of HCGI episodes and the longitudinal prevalence ratio of HCGI days at population and individual levels with a generalized estimating equation (GEE) and generalized linear mixed models (GLMMs), respectively, adjusted for covariates associated with outcome. Results. The incidence rate ratios (active versus sham) were 0.88 (95% confidence interval [CI] = 0.77, 1.00) and 0.85 (95% CI = 0.76, 0.94) HCGI episodes per year estimated by GEE and GLMM models, respectively. The corresponding longitudinal prevalence ratios were 0.88 (95% CI = 0.74, 1.05) and 0.84 (95% CI = 0.78, 0.90) HCGI days per person per year. Conclusions. We observed reductions in population- and individual-level measures of HCGI associated with use of the active filtration device. These findings suggest the need for further research on the impact of drinking water on the health of sensitive subpopulations. PMID:19762663

A Novel Macroscale Acoustic Device for Blood Filtration.

PubMed

Dutra, Brian; Carmen Mora, Maria; Gerhardson, Tyler I; Sporbert, Brianna; Dufresne, Alexandre; Bittner, Katharine R; Lovewell, Carolanne; Rust, Michael J; Tirabassi, Michael V; Masi, Louis; Lipkens, Bart; Kennedy, Daniel R

2018-03-01

Retransfusion of a patient's own shed blood during cardiac surgery is attractive since it reduces the need for allogeneic transfusion, minimizes cost, and decreases transfusion related morbidity. Evidence suggests that lipid micro-emboli associated with the retransfusion of the shed blood are the predominant causes of the neurocognitive disorders. We have developed a novel acoustophoretic filtration system that can remove lipids from blood at clinically relevant flow rates. Unlike other acoustophoretic separation systems, this ultrasound technology works at the macroscale, and is therefore able to process larger flow rates than typical micro-electromechanical system (MEMS) scale acoustophoretic separation devices. In this work, we have first demonstrated the systematic design of the acoustic device and its optimization, followed by examining the feasibility of the device to filter lipids from the system. Then, we demonstrate the effects of the acoustic waves on the shed blood; examining hemolysis using both haptoglobin formation and lactate dehydrogenase release, as well as the potential of platelet aggregation or inflammatory cascade activation. Finally, in a porcine surgical model, we determined the potential viability of acoustic trapping as a blood filtration technology, as the animal responded to redelivered blood by increasing both systemic and mean arterial blood pressure.

Observations on the use of membrane filtration and liquid impingement to collect airborne microorganisms in various atmospheric environments

USGS Publications Warehouse

Griffin, Dale W.; Gonzalez, C.; Teigell, N.; Petrosky, T.; Northup, D.E.; Lyles, M.

2011-01-01

The influence of sample-collection-time on the recovery of culturable airborne microorganisms using a low-flow-rate membrane-filtration unit and a high-flow-rate liquid impinger were investigated. Differences in recoveries were investigated in four different atmospheric environments, one mid-oceanic at an altitude of ~10.0 m, one on a mountain top at an altitude of ~3,000.0 m, one at ~1.0 m altitude in Tallahassee, Florida, and one at ~1.0 m above ground in a subterranean-cave. Regarding use of membrane filtration, a common trend was observed: the shorter the collection period, the higher the recovery of culturable bacteria and fungi. These data also demonstrated that lower culturable counts were common in the more remote mid-oceanic and mountain-top atmospheric environments with bacteria, fungi, and total numbers averaging (by sample time or method categories) <3.0 colony-forming units (CFU) m -3. At the Florida and subterranean sites, the lowest average count noted was 3.5 bacteria CFU m-3, and the highest averaged 140.4 total CFU m-3. When atmospheric temperature allowed use, the high-volume liquid impinger utilized in this study resulted in much higher recoveries, as much as 10?? greater in a number of the categories (bacterial, fungal, and total CFU). Together, these data illustrated that (1) the high-volume liquid impinger is clearly superior to membrane filtration for aeromicrobiology studies if start-up costs are not an issue and temperature permits use; (2) although membrane filtration is more cost friendly and has a 'typically' wider operational range, its limits include loss of cell viability with increased sample time and issues with effectively extracting nucleic acids for community-based analyses; (3) the ability to recover culturable microorganisms is limited in 'extreme' atmospheric environments and thus the use of a 'limited' methodology in these environments must be taken into account; and (4) the atmosphere culls, i.e., everything is not everywhere. ?? 2010 US Government.

[Renal excretion of methylene-diphosphate-technium-99m. Preliminary observations].

PubMed

Vattimo, A; Martini, G

1983-11-30

The purpose of this study is to elucidate the mechanism of the renal excretion of 99mTc-MDP in man. We compared the renal clearance of 99mTc-MDP and 51Cr-EDTA (glomerular filtration rate agent). Since the 99mTc-MDP is bound to the plasma protein, the free fraction was calculated by dialysis. The clearances were obtained by single-injection technique. The plasma disappearance of the tracers was resolved into three exponential functions and area was calculated. The clearance was calculated by dividing the amount of the tracers excreted during the first four hours and the plasma area. In this study no difference was found in the clearance of the two agents. These findings suggest that the renal excretion of diphosphonate is related to the glomerular filtration rate.

An overview of glomerular filtration rate testing in dogs and cats

PubMed Central

Von Hendy-Willson, Vanessa E.; Pressler, Barrak M.

2010-01-01

Determination of glomerular filtration rate (GFR) is a valuable, yet underused, diagnostic tool for evaluating renal function in dogs and cats. This article first reviews the hormonal and hemodynamic factors which contribute to GFR, followed by a description of considerations when selecting a pharmacokinetic model and methods of animal-to-animal standardization. The best-characterized existing GFR markers, including creatinine, radiolabeled markers, and iohexol, are reviewed in depth, as well as alternative but lesser-used techniques. A weighted means analysis of reported GFR measurements in healthy dogs and cats and a review of selected studies that have examined GFR alterations in animals with naturally-occurring and experimental diseases provide the reader with preliminary guidelines on expected GFR results in these species and disease conditions. PMID:20541957

Dual renin-angiotensin-aldosterone system blockade for diabetic kidney disease.

PubMed

Pichler, Raimund H; de Boer, Ian H

2010-08-01

Blockade of the renin-angiotensin-aldosterone system (RAAS) prevents the development and progression of diabetic kidney disease (DKD). It is controversial whether the simultaneous use of two RAAS inhibitors (ie, dual RAAS blockade) further improves renal outcomes. This review examines the scientific rationale and current clinical evidence addressing the use of dual RAAS blockade to prevent and treat DKD. It is concluded that dual RAAS blockade should not be routinely applied to patients with low or moderate risk of progressive kidney disease (normoalbuminuria or microalbuminuria with preserved glomerular filtration rate). For patients with high risk of progressive kidney disease (substantial albuminuria or impaired glomerular filtration rate), clinicians should carefully weigh the potential risks and benefits of dual RAAS blockade on an individual basis until ongoing clinical trials provide further insight.

Optimization of an enhanced ceramic micro-filter for concentrating E.coli in water

NASA Astrophysics Data System (ADS)

Zhang, Yushan; Guo, Tianyi; Xu, Changqing; Hong, Lingcheng

2017-02-01

Recently lower limit of detection (LOD) is necessary for rapid bacteria detection and analysis applications in clinical practices and daily life. A critical pre-conditioning step for these applications is bacterial concentration, especially for low level of pathogens. Sample volume can be largely reduced with an efficient pre-concentration process. Some approaches such as hollow-fiber ultra-filtration and electrokinetic technique have been applied to bacterial concentration. Since none of these methods can provide a concentrating method with a stable recovery efficiency, bacterial concentration still remains challenging Ceramic micro- filter can be used to concentrate the bacteria but the cross flow system keeps the bacteria in suspension. Similar harvesting bacteria using ultra-filtration showed an average recovery efficiency of 43% [1] and other studies achieved recovery rates greater than 50% [2]. In this study, an enhanced ceramic micro-filter with 0.14 μm pore size was proposed and demonstrated to optimize the concentration of E.coli. A high recovery rate (mean value >90%) and a high volumetric concentration ratio (>100) were achieved. Known quantities (104 to 106 CFU/ml) of E.coli cells were spiked to different amounts of phosphate buffered saline (0.1 to 1 L), and then concentrated to a final retentate of 5 ml to 10 ml. An average recovery efficiency of 95.3% with a standard deviation of 5.6% was achieved when the volumetric con- centration ratio was 10. No significant recovery rate loss was indicated when the volumetric concentration ratio reached up to 100. The effects of multiple parameters on E.coli recovery rate were also studied. The obtained results indicated that the optimized ceramic micro- filtration system can successfully concentrate E.coli cells in water with an average recovery rate of 90.8%.

Assessing the cost effectiveness of using prognostic biomarkers with decision models: case study in prioritising patients waiting for coronary artery surgery

PubMed Central

Henriksson, Martin; Palmer, Stephen; Chen, Ruoling; Damant, Jacqueline; Fitzpatrick, Natalie K; Abrams, Keith; Hingorani, Aroon D; Stenestrand, Ulf; Janzon, Magnus; Feder, Gene; Keogh, Bruce; Shipley, Martin J; Kaski, Juan-Carlos; Timmis, Adam; Sculpher, Mark

2010-01-01

Objective To determine the effectiveness and cost effectiveness of using information from circulating biomarkers to inform the prioritisation process of patients with stable angina awaiting coronary artery bypass graft surgery. Design Decision analytical model comparing four prioritisation strategies without biomarkers (no formal prioritisation, two urgency scores, and a risk score) and three strategies based on a risk score using biomarkers: a routinely assessed biomarker (estimated glomerular filtration rate), a novel biomarker (C reactive protein), or both. The order in which to perform coronary artery bypass grafting in a cohort of patients was determined by each prioritisation strategy, and mean lifetime costs and quality adjusted life years (QALYs) were compared. Data sources Swedish Coronary Angiography and Angioplasty Registry (9935 patients with stable angina awaiting coronary artery bypass grafting and then followed up for cardiovascular events after the procedure for 3.8 years), and meta-analyses of prognostic effects (relative risks) of biomarkers. Results The observed risk of cardiovascular events while on the waiting list for coronary artery bypass grafting was 3 per 10 000 patients per day within the first 90 days (184 events in 9935 patients). Using a cost effectiveness threshold of £20 000-£30 000 (€22 000-€33 000; $32 000-$48 000) per additional QALY, a prioritisation strategy using a risk score with estimated glomerular filtration rate was the most cost effective strategy (cost per additional QALY was <£410 compared with the Ontario urgency score). The impact on population health of implementing this strategy was 800 QALYs per 100 000 patients at an additional cost of £245 000 to the National Health Service. The prioritisation strategy using a risk score with C reactive protein was associated with lower QALYs and higher costs compared with a risk score using estimated glomerular filtration rate. Conclusion Evaluating the cost effectiveness of prognostic biomarkers is important even when effects at an individual level are small. Formal prioritisation of patients awaiting coronary artery bypass grafting using a routinely assessed biomarker (estimated glomerular filtration rate) along with simple, routinely collected clinical information was cost effective. Prioritisation strategies based on the prognostic information conferred by C reactive protein, which is not currently measured in this context, or a combination of C reactive protein and estimated glomerular filtration rate, is unlikely to be cost effective. The widespread practice of using only implicit or informal means of clinically ordering the waiting list may be harmful and should be replaced with formal prioritisation approaches. PMID:20085988

Alport syndrome: its effects on the glomerular filtration barrier and implications for future treatment

PubMed Central

Savige, Judy

2014-01-01

The glomerular filtration barrier comprises a fenestrated capillary endothelium, glomerular basement membrane and podocyte slit diaphragm. Over the past decade we have come to realise that permselectivity depends on size and not necessarily charge, that the molecular sieve depends on the podocyte contractile apparatus and is highly dynamic, and that protein uptake by proximal tubular epithelial cells stimulates signalling and the production of transcription factors and inflammatory mediators. Alport syndrome is the second commonest monogenic cause of renal failure after autosomal dominant polycystic kidney disease. Eighty per cent of patients have X-linked disease caused by mutations in the COL4A5 gene. Most of these result in the replacement of the collagen IV α3α4α5 network with the α1α1α2 heterotrimer. Affected membranes also have ectopic laminin and increased matrix metalloproteinase levels, which makes them more susceptible to proteolysis. Mechanical stress, due to the less elastic membrane and hypertension, interferes with integrin-mediated podocyte–GBM adhesion. Proteinuria occurs when urinary levels exceed tubular reabsorption rates, and initiates tubulointerstitial fibrosis. The glomerular mesangial cells produce increased TGFβ and CTGF which also contribute to glomerulosclerosis. Currently there is no specific therapy for Alport syndrome. However treatment with angiotensin converting enzyme (ACE) inhibitors delays renal failure progression by reducing intraglomerular hypertension, proteinuria, and fibrosis. Our greater understanding of the mechanisms underlying the GBM changes and their consequences in Alport syndrome have provided us with further novel therapeutic targets. PMID:25107927

Evaluating efficacy of filtration + UV-C radiation for ballast water treatment at different temperatures

NASA Astrophysics Data System (ADS)

Casas-Monroy, Oscar; Linley, Robert D.; Chan, Po-Shun; Kydd, Jocelyn; Vanden Byllaardt, Julie; Bailey, Sarah

2018-03-01

To prevent new ballast water-mediated introductions of aquatic nonindigenous species (NIS), many ships will soon use approved Ballast Water Management Systems (BWMS) to meet discharge standards for the maximum number of viable organisms in ballast water. Type approval testing of BWMS is typically conducted during warmer seasons when plankton concentrations are highest, despite the fact that ships operate globally year-round. Low temperatures encountered in polar and cool temperate climates, particularly during the winter season, may impact treatment efficacy through changes in plankton community composition, biological metabolic rates or chemical reaction rates. Filtration + UV irradiance is one of the most common ballast water treatment methods, but its effectiveness at low temperatures has not been assessed. The objective in this study was to examine the efficacy of filtration + UV-C irradiation treatment at low temperatures for removal or inactivation of phytoplankton and zooplankton populations during simulated ballast water treatment. Organisms from two size classes (≥ 10 to < 50 μm and ≥ 50 μm) were identified and enumerated using microscope and culture techniques. The response of organisms in both size categories to UV-C irradiation was evident across a range of temperatures (18 °C, 12 °C and 2 °C) as a significant decrease in concentration between controls and treated samples. Results indicate that filtration + UV-C irradiation will be effective at low temperatures, with few viable organisms ≥ 10 to < 50 μm recorded even 21 days following UV exposure (significantly lower than in the control treatment).

The Radiologist Is in, but Was it Worth the Wait? Radiology Resident Note Quality in an Outpatient Interventional Radiology Clinic.

PubMed

Abboud, Salim E; Soriano, Stephanie; Abboud, Rayan; Patel, Indravadan; Davidson, Jon; Azar, Nami R; Nakamoto, Dean A

Preprocedural evaluation of patients in an interventional radiology (IR) clinic is a complex synthesis of physical examination and imaging findings, and as IR transitions to an independent clinical specialty, such evaluations will become an increasingly critical component of a successful IR practice and quality patient care. Prior research suggests that preprocedural evaluations increased patient's perceived quality of care and may improve procedural technical success rates. Appropriate documentation of a preprocedural evaluation in the medical record is also paramount for an interventional radiologist to add value and function as an effective member of a larger IR service and multidisciplinary health care team. The purpose of this study is to examine the quality of radiology resident notes for patients seen in an outpatient IR clinic at a single academic medical center before and after the adoption of clinic note template with reminders to include platelet count, international normalized ratio, glomerular filtration rate, and plan for periprocedural coagulation status. Before adoption of the template, platelet count, international normalized ratio, glomerular filtration rate and an appropriate plan for periprocedural coagulation status were documented in 72%, 82%, 42%, and 33% of patients, respectively. After adoption of the template, appropriate documentation of platelet count, international normalized ratio, and glomerular filtration rate increased to 96%, and appropriate plan for periprocedural coagulation status was documented in 83% of patients. Patient evaluation and clinical documentation skills may not be adequately practiced during radiology residency, and tools such as templates may help increase documentation quality by radiology residents. Copyright © 2017 Elsevier Inc. All rights reserved.

40 CFR 141.73 - Filtration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... filtration. (1) For systems using diatomaceous earth filtration, the turbidity level of representative... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system... treatment or direct filtration. (1) For systems using conventional filtration or direct filtration, the...

40 CFR 141.73 - Filtration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... filtration. (1) For systems using diatomaceous earth filtration, the turbidity level of representative... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system... treatment or direct filtration. (1) For systems using conventional filtration or direct filtration, the...

40 CFR 141.73 - Filtration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... filtration. (1) For systems using diatomaceous earth filtration, the turbidity level of representative... PRIMARY DRINKING WATER REGULATIONS Filtration and Disinfection § 141.73 Filtration. A public water system... treatment or direct filtration. (1) For systems using conventional filtration or direct filtration, the...

Numerical simulation of two-phase filtration in the near well bore zone

NASA Astrophysics Data System (ADS)

Maksat, Kalimoldayev; Kalipa, Kuspanova; Kulyash, Baisalbayeva; Orken, Mamyrbayev; Assel, Abdildayeva

2018-04-01

On the basis of the fundamental laws of energy conservation, nonstationary processes of filtration of two-phase liquids in multilayered reservoirs in the near well bore zone are considered. Number of reservoirs, fluid pressure in the given reservoirs, reservoir permeability, oil viscosity, etc. are taken into account upon that. Plane-parallel flow and axisymmetric cases have been studied. In the numerical solution, non-structured meshes are used. Closer to the well, the meshes thicken. The integration step over time is defined by the generalized Courant inequality. As a result, there are no large oscillations in the numerical solutions obtained. Oil production rates, Poisson's ratios, D-diameters of the well, filter height, filter permeability, and cumulative thickness of the filter cake and the area have been taken as the main inputs in numerical simulation of non-stationary processes of two-phase filtration.

Effluent characterization from a conical pressurized fluid bed

NASA Technical Reports Server (NTRS)

Priem, R. J.; Rollbuhler, R. J.; Patch, R. W.

1977-01-01

To obtain useable corrosion and erosion results it was necessary to have data with several levels of particulate matter in the hot gases. One level of particulate loading was as low as possible so that ideally no erosion and only corrosion occurred. A conical fluidized bed was used to obtain some degree of filtration through the top of the bed which would not be highly fluidized. This would minimize the filtration required for the hot gases or conversely the amount of particulate matter in the hot gases after a given level of filtration by cyclones and/or filters. The data obtained during testing characterized the effluent from the bed at different test conditions. A range of bed heights, coal flows, air flows, limestone flows, and pressure are represented. These tests were made to determine the best operating conditions prior to using the bed to determine erosion and corrosion rates of typical turbine blade materials.

The application of low angle light scattering to evaluate qualitatively and quantitatively the dynamics of formation of oligomers in heme protein sensors

NASA Astrophysics Data System (ADS)

Sabino, Luis G.; Guimarães, Wellinson Gadelha; Costa, Pedro Mikael; Carepo, Marta S. P.; Gondim, Ana C. S.; Lopes, Luiz G. F.; Sousa, Eduardo H. S.

2016-03-01

The aim of this study is to investigate the structural organization and oligomerization properties of the sensory kinase protein DevS using low-angle light scattering (LALS) and gel filtration chromatography (HPLC). In addition, the structural characteristics of FixL and BSA were investigated and compared with DevS to better elucidate LALS technique. DevS is a direct and specific O2 sensing protein in Mycobacterium tuberculosis and acts as an activator of the transcription factor protein DevR. This latter triggers the latency state of tuberculosis under hypoxic conditions. DevS has been briefly evaluated under different conditions of concentration, ionic strength and temperature. LALS and gel filtration (HPLC) analysis were performed right after DevS purification process. The results of LALS for BSA proved to be highly reliable with a Rh value of c.a. 3.7 nm. Considering BSA a globular protein, the molecular weight estimative, using LALS was near 67 KDa, which is reasonably within the value reported in the literature. Preliminary LALS results showed a hydrodynamic radius (Rh) varying from 4.2-15.0 nm for DevS protein, and an average of 6.7 nm. These data supported, along with gel filtration, a dimer (~130 KDa) and tetramer (255 KDa) as the main DevS species. Additionally, it was found higher oligomeric species by gel filtration suggesting either an equilibrium of oligomers or an aggregation process that deserves further studies.

The significance of some methodological effects on filtration and ingestion rates of the rotifer Brachionus plicatilis

NASA Astrophysics Data System (ADS)

Schlosser, H. J.; Anger, K.

1982-06-01

Filtration rate (F) and ingestion rate (I) were measured in the rotifer Brachionus plicatilis feeding on the flagellate Dunaliella spec. and on yeast cells (Saccharomyces cerevisiae). 60-min experiments in rotating bottles served as a standard for testing methodological effects on levels of F and I. A lack of rotation reduced F values by 40 %, and a rise in temperature from 18° to 23.5 °C increased them by 42 %. Ingestion rates increased significantly up to a particle (yeast) concentration of ca. 600-800 cells · μl-1; then they remained constant, whereas filtration rates decreased beyond this threshold. Rotifer density (up to 1000 ind · ml-1) and previous starvation (up to 40 h) did not significantly influence food uptake rates. The duration of the experiment proved to have the most significant effect on F and I values: in 240-min experiments, these values were on the average more than 90 % lower than in 15-min experiments. From this finding it is concluded that ingestion rates obtained from short-term experiments (60 min or less) cannot be used in energy budgets, because they severely overestimate the actual long-term feeding capacity of the rotifers. At the lower end of the particle size spectrum (2 to 3 µm) there are not only food cells, but apparently also contaminating faecal particles. Their number increased with increasing duration of experiments and lead to an underestimation of F and I. Elemental analyses of rotifers and their food suggest that B. plicatilis can ingest up to 0.6 mJ or ca. 14 % of its own body carbon within 15 min. The long term average was estimated as 3.4 mJ · ind-1 · d-1 or ca. 75 % of body carbon · d-1.

About Chronic Kidney Disease

MedlinePlus

... Donate A to Z Health Guide About Chronic Kidney Disease Tweet Share Print Email Chronic kidney disease ( ... about Glomerular Filtration Rate (GFR) What is chronic kidney disease (CKD)? Chronic kidney disease includes conditions that ...

Skin Autofluorescence and Subclinical Atherosclerosis in Mild to Moderate Chronic Kidney Disease: A Case-Control Study.

PubMed

Sánchez, Enric; Betriu, Àngels; Arroyo, David; López, Carolina; Hernández, Marta; Rius, Ferran; Fernández, Elvira; Lecube, Albert

2017-01-01

Advanced glycation end-products (AGEs) are increased and predict mortality in patients with chronic kidney disease (CKD) who are undergoing hemodialysis, irrespective of the presence of type 2 diabetes. However, little information exits about the relationship between AGEs and subclinical atherosclerosis at the early stages of CKD. A case-control study was performed including 87 patients with mild-to-moderate stages of CKD (glomerular filtration rate from 89 to 30 ml/min/per 1.73m2) and 87 non-diabetic non-CKD subjects matched by age, gender, body mass index, and waist circumference. Skin autofluorescence (AF), a non-invasive assessment of AGEs, was measured. The presence of atheromatous disease in carotid and femoral arteries was evaluated using vascular ultrasound, and vascular age and SCORE risk were estimated. Patients with mild-to-moderate stages of CKD showed an increase in skin AF compared with control subjects (2.5±0.6 vs. 2.2±0.4 AU, p<0.001). A skin AF value >2.0 AU was accompanied by a 3-fold increased risk of detecting the presence of an atheromathous plaque (OR 3.0, 95% CI 1.4-6.5, p = 0.006). When vascular age was assessed through skin AF, subjects with CKD were almost 12 years older than control subjects (70.3±25.5 vs. 58.5±20.2 years, p = 0.001). Skin AF was negatively correlated with glomerular filtration rate (r = -0.354, p<0.001) and LDL-cholesterol (r = -0.269, p = 0.001), and positively correlated with age (r = 0.472, p<0.001), pulse pressure (r = 0.238, p = 0.002), and SCORE risk (r = 0.451, p<0.001). A stepwise multivariate regression analysis showed that age and glomerular filtration rate independently predicted skin AF (R2 = 0.289, p<0.001). Skin AF is elevated in patients with mild-to-moderate CKD compared with control subjects. This finding may be independently associated with the glomerular filtration rate and the presence of subclinical atheromatous disease. Therefore, the use of skin AF may help to accurately evaluate the real cardiovascular risk at the early stages of CKD.

The renal response to electrical stimulation of renal efferent sympathetic nerves in the anaesthetized greyhound.

PubMed Central

Poucher, S M; Karim, F

1991-01-01

1. The effect of direct electrical stimulation of the renal efferent nerves upon renal haemodynamics and function was studied in greyhounds anaesthetized with chloralose and artificially ventilated. The left kidney was neurally and vascularly isolated, and perfused with blood from one of the femoral arteries at a constant pressure of 99 +/- 1 mmHg. Renal blood flow was measured with a cannulating electromagnetic flow probe placed in the perfusion circuit, glomerular filtration rate by creatinine clearance, urinary sodium excretion by flame photometry and solute excretion by osmometry. Beta-Adrenergic receptor activation was blocked by the infusion of dl-propranolol (17 micrograms kg-1 min-1). The peripheral ends of the ligated renal nerves were stimulated at 0.5, 1.0, 1.5 and 2.0 Hz. 2. At 0.5 Hz frequency only osmolar excretion was significantly reduced (10.3 +/- 3.2%, P less than 0.05, n = 6). Reductions in sodium excretion (53.6 +/- 8.5%, P less than 0.01, n = 6) and water excretion (26.9 +/- 8.0%, P less than 0.05, n = 6) and further reductions of osmolar excretion (20.7 +/- 3.7%, P less than 0.01, n = 6) were observed at 1.0 Hz; however, these were observed in the absence of significant changes in renal blood flow and glomerular filtration rate. Significant reductions were observed in glomerular filtration rate at 1.5 Hz (16.3 +/- 4.1%, P less than 0.02, n = 5) and in renal blood flow at 2.0 Hz (13.1 +/- 4.0%, P less than 0.05, n = 5). Further reductions in urine flow and sodium excretion were also observed at these higher frequencies. 3. These results clearly show that significant changes in renal tubular function can occur in the absence of changes in renal blood flow and glomerular filtration rate when the renal nerves are stimulated electrically from a zero baseline activity up to a frequency of 1.5 Hz. Higher frequencies caused significant changes in both renal haemodynamics and function. PMID:2023113

The giraffe kidney tolerates high arterial blood pressure by high renal interstitial pressure and low glomerular filtration rate.

PubMed

Damkjaer, M; Wang, T; Brøndum, E; Østergaard, K H; Baandrup, U; Hørlyck, A; Hasenkam, J M; Smerup, M; Funder, J; Marcussen, N; Danielsen, C C; Bertelsen, M F; Grøndahl, C; Pedersen, M; Agger, P; Candy, G; Aalkjaer, C; Bie, P

2015-08-01

The tallest animal on earth, the giraffe (Giraffa camelopardalis) is endowed with a mean arterial blood pressure (MAP) twice that of other mammals. The kidneys reside at heart level and show no sign of hypertension-related damage. We hypothesized that a species-specific evolutionary adaption in the giraffe kidney allows normal for size renal haemodynamics and glomerular filtration rate (GFR) despite a MAP double that of other mammals. Fourteen anaesthetized giraffes were instrumented with vascular and bladder catheters to measure glomerular filtration rate (GFR) and effective renal plasma flow (ERPF). Renal interstitial hydrostatic pressure (RIHP) was assessed by inserting a needle into the medullary parenchyma. Doppler ultrasound measurements provided renal artery resistive index (RI). Hormone concentrations as well as biomechanical, structural and histological characteristics of vascular and renal tissues were determined. GFR averaged 342 ± 99 mL min(-1) and ERPF 1252 ± 305 mL min(-1) . RIHP varied between 45 and 140 mmHg. Renal pelvic pressure was 39 ± 2 mmHg and renal venous pressure 32 ± 4 mmHg. A valve-like structure at the junction of the renal and vena cava generated a pressure drop of 12 ± 2 mmHg. RI was 0.27. The renal capsule was durable with a calculated burst pressure of 600 mmHg. Plasma renin and AngII were 2.6 ± 0.5 mIU L(-1) and 9.1 ± 1.5 pg mL(-1) respectively. In giraffes, GFR, ERPF and RI appear much lower than expected based on body mass. A strong renal capsule supports a RIHP, which is >10-fold that of other mammals effectively reducing the net filtration pressure and protecting against the high MAP. © 2015 Scandinavian Physiological Society. Published by John Wiley & Sons Ltd.

Albumin-associated free fatty acids induce macropinocytosis in podocytes

PubMed Central

Chung, Jun-Jae; Huber, Tobias B.; Gödel, Markus; Jarad, George; Hartleben, Björn; Kwoh, Christopher; Keil, Alexander; Karpitskiy, Aleksey; Hu, Jiancheng; Huh, Christine J.; Cella, Marina; Gross, Richard W.; Miner, Jeffrey H.; Shaw, Andrey S.

2015-01-01

Podocytes are specialized epithelial cells in the kidney glomerulus that play important structural and functional roles in maintaining the filtration barrier. Nephrotic syndrome results from a breakdown of the kidney filtration barrier and is associated with proteinuria, hyperlipidemia, and edema. Additionally, podocytes undergo changes in morphology and internalize plasma proteins in response to this disorder. Here, we used fluid-phase tracers in murine models and determined that podocytes actively internalize fluid from the plasma and that the rate of internalization is increased when the filtration barrier is disrupted. In cultured podocytes, the presence of free fatty acids (FFAs) associated with serum albumin stimulated macropinocytosis through a pathway that involves FFA receptors, the Gβ/Gγ complex, and RAC1. Moreover, mice with elevated levels of plasma FFAs as the result of a high-fat diet were more susceptible to Adriamycin-induced proteinuria than were animals on standard chow. Together, these results support a model in which podocytes sense the disruption of the filtration barrier via FFAs bound to albumin and respond by enhancing fluid-phase uptake. The response to FFAs may function in the development of nephrotic syndrome by amplifying the effects of proteinuria. PMID:25915582

New optical probes for the continuous monitoring of renal function

NASA Astrophysics Data System (ADS)

Dorshow, Richard B.; Asmelash, Bethel; Chinen, Lori K.; Debreczeny, Martin P.; Fitch, Richard M.; Freskos, John N.; Galen, Karen P.; Gaston, Kimberly R.; Marzan, Timothy A.; Poreddy, Amruta R.; Rajagopalan, Raghavan; Shieh, Jeng-Jong; Neumann, William L.

2008-02-01

The ability to continuously monitor renal function via the glomerular filtration rate (GFR) in the clinic is currently an unmet medical need. To address this need we have developed a new series of hydrophilic fluorescent probes designed to clear via glomerular filtration for use as real time optical monitoring agents at the bedside. The ideal molecule should be freely filtered via the glomerular filtration barrier and be neither reabsorbed nor secreted by the renal tubule. In addition, we have hypothesized that a low volume of distribution into the interstitial space could also be advantageous. Our primary molecular design strategy employs a very small pyrazine-based fluorophore as the core unit. Modular chemistry for functionalizing these systems for optimal pharmacokinetics (PK) and photophysical properties have been developed. Structure-activity relationship (SAR) and pharmacokinetic (PK) studies involving hydrophilic pyrazine analogues incorporating polyethylene glycol (PEG), carbohydrate, amino acid and peptide functionality have been a focus of this work. Secondary design strategies for minimizing distribution into the interstitium while maintaining glomerular filtration include enhancing molecular volume through PEG substitution. In vivo optical monitoring experiments with advanced candidates have been correlated with plasma PK for measurement of clearance and hence GFR.

Importance of calcium and magnesium in water - water hardening

NASA Astrophysics Data System (ADS)

Barloková, D.; Ilavský, J.; Kapusta, O.; Šimko, V.

2017-10-01

Basic information about importance of calcium and magnesium in water, about their properties, effect to human health, problems what can cause under the lower (< 1 mmol/L) and higher (> 5 mmol/L) concentrations in water supply distribution systems, the most commonly used methods of water hardening are presented. The article contains the water hardening results carried out during the pilot plant experiments in WTP Hriňová and WTP Turček. For water hardening, treated water at the end of the process line, i.e., after coagulation, sedimentation and filtration, saturated with CO2 and filtrated through half-burnt dolomite material (PVD) was used. The results show that the filtration rate is 17.1 m/h in the case of WTP Hriňová and 15.2 m/h in the case of WTP Turček to achieve the recommended concentration of Ca and Mg in the treated water after the addition of CO2 and filtration through PVD. The longer the water contact time with PVD (depending on the CO2 content), the more water is enriched with magnesium, but the calcium concentration has not so much increased.

ISS Ambient Air Quality: Updated Inventory of Known Aerosol Sources

NASA Technical Reports Server (NTRS)

Meyer, Marit

2014-01-01

Spacecraft cabin air quality is of fundamental importance to crew health, with concerns encompassing both gaseous contaminants and particulate matter. Little opportunity exists for direct measurement of aerosol concentrations on the International Space Station (ISS), however, an aerosol source model was developed for the purpose of filtration and ventilation systems design. This model has successfully been applied, however, since the initial effort, an increase in the number of crewmembers from 3 to 6 and new processes on board the ISS necessitate an updated aerosol inventory to accurately reflect the current ambient aerosol conditions. Results from recent analyses of dust samples from ISS, combined with a literature review provide new predicted aerosol emission rates in terms of size-segregated mass and number concentration. Some new aerosol sources have been considered and added to the existing array of materials. The goal of this work is to provide updated filtration model inputs which can verify that the current ISS filtration system is adequate and filter lifetime targets are met. This inventory of aerosol sources is applicable to other spacecraft, and becomes more important as NASA considers future long term exploration missions, which will preclude the opportunity for resupply of filtration products.

Epidemiological study of air filtration systems for preventing PRRSV infection in large sow herds.

PubMed

Alonso, Carmen; Murtaugh, Michael P; Dee, Scott A; Davies, Peter R

2013-10-01

Porcine reproductive and respiratory syndrome virus (PRRSV) is the most economically significant pathogen in the US swine industry. Aerosol transmission among herds is a major concern in pig dense regions and filtration of incoming air, in combination with standard biosecurity procedures, has been demonstrated to prevent transmission of PRRSV into susceptible herds. To quantify the impact of air filtration on reducing risk of PRRSV outbreaks, we compared the incidence rate of new PRRSV introductions in 20 filtered and 17 non-filtered control sow herds in a swine dense region of North America during a 7 year study period. Events of novel virus introduction were ascertained by phylogenetic analysis of PRRSV ORF5 gene sequences. Putative new viruses were defined as exogenous (introduced) based on ORF5 nucleotide sequence differences compared to previous farm isolates. The influence of sequence difference cut-off values ranging from 2 to 10% on case definition and relative risk were evaluated. Non-filtered farms incurred about 0.5 outbreaks per year, with a seasonal increase in risk in cooler periods. Baseline risk, prior to filtration, in treatment farms was approximately 0.75 per year, approximately 50% higher than in control farms. Air filtration significantly reduced risk of PRRSV introduction events to 0.06-0.22 outbreaks per year, depending on the cut-off values used to classify a virus isolate as new to the herd. Overall, air filtration led to an approximately 80% reduction in risk of introduction of novel PRRSV, indicating that on large sow farms with good biosecurity in swine-dense regions, approximately four-fifths of PRRSV outbreaks may be attributable to aerosol transmission. Copyright © 2013 Elsevier B.V. All rights reserved.

Novel Filtration Markers for GFR Estimation

PubMed Central

Inker, Lesley A.; Coresh, Josef; Levey, Andrew S.; Eckfeldt, John H.

2017-01-01

Creatinine-based glomerular filtration rate estimation (eGFRcr) has been improved and refined since the 1970s through both the Modification of Diet in Renal Disease (MDRD) Study equation in 1999 and the CKD Epidemiology Collaboration (CKD-EPI) equation in 2009, with current clinical practice dependent primarily on eGFR for accurate assessment of GFR. However, researchers and clinicians have recognized limitations of relying on creatinine as the only filtration marker, which can lead to inaccurate GFR estimates in certain populations due to the influence of non-GFR determinants of serum or plasma creatinine. Therefore, recent literature has proposed incorporation of multiple serum or plasma filtration markers into GFR estimation to improve precision and accuracy and decrease the impact of non-GFR determinants for any individual biomarker. To this end, the CKD-EPI combined creatinine-cystatin C equation (eGFRcr-cys) was developed in 2012 and demonstrated superior accuracy to equations relying on creatinine or cystatin C alone (eGFRcr or eGFRcys). Now, the focus has broadened to include additional novel filtration markers to further refine and improve GFR estimation. Beta-2-microglobulin (B2M) and beta-trace-protein (BTP) are two filtration markers with established assays that have been proposed as candidates for improving both GFR estimation and risk prediction. GFR estimating equations based on B2M and BTP have been developed and validated, with the CKD-EPI combined BTP-B2M equation (eGFRBTP-B2M) demonstrating similar performance to eGFR and eGFR. Additionally, several studies have demonstrated that both B2M and BTP are associated with outcomes in CKD patients, including cardiovascular events, ESRD and mortality. This review will primarily focus on these two biomarkers, and will highlight efforts to identify additional candidate biomarkers through metabolomics-based approaches. PMID:29333147

Determination of split renal function using dynamic CT-angiography: preliminary results.

PubMed

Helck, Andreas; Schönermarck, Ulf; Habicht, Antje; Notohamiprodjo, Mike; Stangl, Manfred; Klotz, Ernst; Nikolaou, Konstantin; la Fougère, Christian; Clevert, Dirk Andrè; Reiser, Maximilian; Becker, Christoph

2014-01-01

To determine the feasibility of a dynamic CT angiography-protocol with regard to simultaneous assessment of renal anatomy and function. 7 healthy potential kidney donors (58 ± 7 years) underwent a dynamic computed tomography angiography (CTA) using a 128-slice CT-scanner with continuous bi-directional table movement, allowing the coverage of a scan range of 18 cm within 1.75 sec. Twelve scans of the kidneys (n = 14) were acquired every 3.5 seconds with the aim to simultaneously obtain CTA and renal function data. Image quality was assessed quantitatively (HU-measurements) and qualitatively (grade 1-4, 1 = best). The glomerular filtration rate (GFR) was calculated by a modified Patlak method and compared with the split renal function obtained with renal scintigraphy. Mean maximum attenuation was 464 ± 58 HU, 435 ± 48 HU and 277 ± 29 HU in the aorta, renal arteries, and renal veins, respectively. The abdominal aorta and all renal vessels were depicted excellently (grade 1.0). The image quality score for cortex differentiation was 1.6 ± 0.49, for the renal parenchyma 2.4 ± 0.49. GFR obtained from dynamic CTA correlated well with renal scintigraphy with a correlation coefficient of r = 0.84; P = 0.0002 (n = 14). The average absolute deviation was 1.6 mL/min. The average effective dose was 8.96 mSv. Comprehensive assessment of renal anatomy and function is feasible using a single dynamic CT angiography examination. The proposed protocol may help to improve management in case of asymmetric kidney function as well as to simplify evaluation of potential living kidney donors.

Numerical investigation of adhesion effects on solid particles filtration efficiency

NASA Astrophysics Data System (ADS)

Shaffee, Amira; Luckham, Paul; Matar, Omar K.

2017-11-01

Our work investigate the effectiveness of particle filtration process, in particular using a fully-coupled Computational Fluid Dynamics (CFD) and Discrete Element Method (DEM) approach involving poly-dispersed, adhesive solid particles. We found that an increase in particle adhesion reduces solid production through the opening of a wire-wrap type filter. Over time, as particle agglomerates continuously deposit on top of the filter, layer upon layer of particles is built on top of the filter, forming a particle pack. It is observed that with increasing particle adhesion, the pack height build up also increases and hence decreases the average particle volume fraction of the pack. This trend suggests higher porosity and looser packing of solid particles within the pack with increased adhesion. Furthermore, we found that the pressure drop for adhesive case is lower compared to non-adhesive case. Our results suggest agglomerating solid particles has beneficial effects on particle filtration. One important application of these findings is towards designing and optimizing sand control process for a hydrocarbon well with excessive sand production which is major challenge in oil and gas industry. Funding from PETRONAS and RAEng UK for Research Chair (OKM) gratefully acknowledged.

The cell engineering construction and function evaluation of multi-layer biochip dialyzer.

PubMed

Zhu, Wen; Li, Jiwei; Liu, Jianfeng

2013-10-01

We report the fabrication and function evaluation of multi-layer biochip dialyzer. Such device may potentially be applied to the wearable hemodialysis systems. By merging the advantages of microfluidic chip technology with cell engineering, both functions of glomerular filtration and renal tubule physiological activity are integrated in the same device. This device is designed into a laminated structure, in which the chip number of the superimposed layer can be arbitrarily tailored in accordance with the requirements of dialysis capacity. We propose that such structure can overcome the obstacles of large size and detached structure of the traditional hollow fiber dialyzer. To construct this multilayer biochips dialyzer, two types of dialyzer device with two-layered and six-layered chips are assembled, respectively. Cell adhesion and proliferation on three different dialysis membrane materials under static and dynamic conditions are investigated and compared. The filtration capability, re-absorption function and excrete ammonia function of the resulting multi-layer biochip dialyzer are evaluated. The results reveal that the constructed device can perform higher filtration efficiency and also play a role of renal tubule. This methodology may be useful in developing "scaling down" artificial kidneys that can act as wearable or even implantable hemodialysis systems.

Effects of steam sterilization on thermogelling chitosan-based gels.

PubMed

Jarry, C; Chaput, C; Chenite, A; Renaud, M A; Buschmann, M; Leroux, J C

2001-01-01

A new thermogelling chitosan-glycerophosphate system has been recently proposed for biomedical applications such as drug and cell delivery. The objectives of this work were to characterize the effect of steam sterilization on the in vitro and in vivo end performances of the gel and to develop a filtration-based method to assess its sterility. Autoclaving 2% (w/v) chitosan solutions for as short as 10 min resulted in a 30% decrease in molecular weight, 3-5-fold decrease in dynamic viscosity, and substantial loss of mechanical properties of the resulting gel. However, sterilization did not impair the ability of the system to form a gel at 37 degrees C. The antimicrobial activity of chitosan against several microorganisms was evaluated after inoculation of chitosan solutions and removal of the cells by filtration. It was found that, although chitosan was bacteriostatic against the heat sterilization bioindicator Bacillus stearothermophilus, the bacteria could rapidly grow after separation from the chitosan solution by filtration. This indicated that B. stearothermophilus is an adequate strain to validate a heat sterilization method on chitosan preparations, and accordingly this strain was used to assess the sterility of chitosan solution following a 10 min autoclaving time. Copyright 2001 John Wiley & Sons, Inc.

A case of unilateral nephrectomy performed for autosomal dominant polycystic kidney disease with marked unilateral enlargement.

PubMed

Makabe, Shiho; Kataoka, Hiroshi; Kondo, Tsunenori; Tanabe, Kazunari; Tsuchiya, Ken; Nitta, Kosaku; Mochizuki, Toshio

2018-05-01

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the occurrence of multiple cysts that increase the size of both kidneys, progressively reducing kidney function. Usually the cysts occur bilaterally, and there is no difference in the degree of cyst enlargement between the left and right. Here, we report a case of ADPKD in which kidney size increased markedly on the left side and was accompanied by severe abdominal distension and discomfort. Renal dynamic scintigraphy revealed a severe reduction in function of the left kidney compared with the right. Open left nephrectomy was performed. No change in renal function was observed postoperatively [preoperative estimated glomerular filtration rate (eGFR): 57.6 mL/min/1.73 m 2 , 3-month postoperative eGFR: 56.4 mL/min/1.73 m 2 ], and the abdominal symptoms subsided. When one kidney is markedly larger than the other, the cause and status of the laterality should be evaluated by using renal dynamic scintigraphy in addition to other examinations such as computed tomography or magnetic resonance imaging. Unilateral nephrectomy should be considered as a potential treatment.

Dynamics of hydrophobic organic contaminants in the Baltic proper pelagial

DOE Office of Scientific and Technical Information (OSTI.GOV)

Axelman, J.; Broman, D.; Naef, C.

Hydrophobic organic contaminants occur in different forms in natural water. Apart from being truly dissolved in water they partition into dissolved organic carbon (DOC) and particles of different sizes including pelagic bacteria, phytoplankton and zooplankton. The distribution between the different forms is dependent on carbon turnover rates in and transport between the different compartments and on the physical and chemical properties of the compound in focus. The water phase, the DOC-phase and two particle size fractions, 0.2--2pm and 2--20 pm representing the base of the pelagic food web, were analyzed for their content of PCBs and PAHs during summer andmore » winter conditions in the open sea in the Baltic proper. New methods for separating truly dissolved from DOC-bound compounds have been developed using a high capacity perfusion adsorbent and large scale gas sparging. The small particle size fraction was sampled using high volume tangential flow filtration. The possibility to separate between these four different compartments has given a more detailed picture of the short term dynamics of hydrophobic organic compounds in the important base of the pelagial food web.« less

Nephron blood flow dynamics measured by laser speckle contrast imaging

PubMed Central

Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V.; Pavlov, Alexey N.; Cupples, William A.; Sorensen, Charlotte Mehlin

2011-01-01

Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50–100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic techniques for extracting the desired data and for examining them for evidence of nephron synchronization. Synchronized TGF oscillations were detected in pairs or triplets of nephrons. The amplitude and the frequency of the oscillations changed with time, as did the patterns of synchronization. Synchronization may take place among nephrons not immediately adjacent on the surface of the kidney. PMID:21048025

Water filtration using plant xylem.

PubMed

Boutilier, Michael S H; Lee, Jongho; Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

2014-01-01

Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees--a readily available, inexpensive, biodegradable, and disposable material--can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm(3) of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings.

Population based screening for chronic kidney disease: cost effectiveness study.

PubMed

Manns, Braden; Hemmelgarn, Brenda; Tonelli, Marcello; Au, Flora; Chiasson, T Carter; Dong, James; Klarenbach, Scott

2010-11-08

To determine the cost effectiveness of one-off population based screening for chronic kidney disease based on estimated glomerular filtration rate. Cost utility analysis of screening with estimated glomerular filtration rate alone compared with no screening (with allowance for incidental finding of cases of chronic kidney disease). Analyses were stratified by age, diabetes, and the presence or absence of proteinuria. Scenario and sensitivity analyses, including probabilistic sensitivity analysis, were performed. Costs were estimated in all adults and in subgroups defined by age, diabetes, and hypertension. Publicly funded Canadian healthcare system. Large population based laboratory cohort used to estimate mortality rates and incidence of end stage renal disease for patients with chronic kidney disease over a five year follow-up period. Patients had not previously undergone assessment of glomerular filtration rate. Lifetime costs, end stage renal disease, quality adjusted life years (QALYs) gained, and incremental cost per QALY gained. Compared with no screening, population based screening for chronic kidney disease was associated with an incremental cost of $C463 (Canadian dollars in 2009; equivalent to about £275, €308, US $382) and a gain of 0.0044 QALYs per patient overall, representing a cost per QALY gained of $C104 900. In a cohort of 100 000 people, screening for chronic kidney disease would be expected to reduce the number of people who develop end stage renal disease over their lifetime from 675 to 657. In subgroups of people with and without diabetes, the cost per QALY gained was $C22 600 and $C572 000, respectively. In a cohort of 100 000 people with diabetes, screening would be expected to reduce the number of people who develop end stage renal disease over their lifetime from 1796 to 1741. In people without diabetes with and without hypertension, the cost per QALY gained was $C334 000 and $C1 411 100, respectively. Population based screening for chronic kidney disease with assessment of estimated glomerular filtration rate is not cost effective overall or in subgroups of people with hypertension or older people. Targeted screening of people with diabetes is associated with a cost per QALY that is similar to that accepted in other interventions funded by public healthcare systems.

68Ga-EDTA PET/CT imaging and plasma clearance for glomerular filtration rate quantification: comparison to conventional 51Cr-EDTA.

PubMed

Hofman, Michael; Binns, David; Johnston, Val; Siva, Shankar; Thompson, Mick; Eu, Peter; Collins, Marnie; Hicks, Rodney J

2015-03-01

Glomerular filtration rate (GFR) can accurately be determined using (51)Cr-ethylenediaminetetraacetic acid (EDTA) plasma clearance counting but is time-consuming and requires technical skills and equipment not always available in imaging departments. (68)Ga-EDTA can be readily available using an onsite generator, and PET/CT enables both imaging of renal function and accurate camera-based quantitation of clearance of activity from blood and its appearance in the urine. This study aimed to assess agreement between (68)Ga-EDTA GFR ((68)Ga-GFR) and (51)Cr-EDTA GFR ((51)Cr-GFR), using serial plasma sampling and PET imaging. (68)Ga-EDTA and (51)Cr-EDTA were injected concurrently in 31 patients. Dynamic PET/CT encompassing the kidneys was acquired for 10 min followed by 3 sequential 3-min multibed step acquisitions from kidneys to bladder. PET quantification was performed using renal activity at 1-2 min (PETinitial), renal excretion at 2-10 min (PETearly), and, subsequently, urinary excretion into the collecting system and bladder (PETlate). Plasma sampling at 2, 3, and 4 h was performed, with (68)Ga followed by (51)Cr counting after positron decay. The level of agreement for GFR determination was calculated using a Bland-Altman plot and Pearson correlation coefficient (PCC). (51)Cr-GFR ranged from 10 to 220 mL/min (mean, 85 mL/min). There was good agreement between (68)Ga-GFR and (51)Cr-GFR using serial plasma sampling, with a Bland-Altman bias of -14 ± 20 mL/min and a PCC of 0.94 (95% confidence interval, 0.88-0.97). Of the 3 methods used for camera-based quantification, the strongest correlation was for plasma sampling-derived GFR with PETlate (PCC of 0.90; 95% confidence interval, 0.80-0.95). (68)Ga-GFR agreed well with (51)Cr-GFR for estimation of GFR using serial plasma counting. PET dynamic imaging provides a method to estimate GFR without plasma sampling, with the additional advantage of enabling renal imaging in a single study. Additional validation in a larger cohort is warranted to further assess utility. © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Dewatering of Chlorella pyrenoidosa using diatomite dynamic membrane: filtration performance, membrane fouling and cake behavior.

PubMed

Zhang, Yalei; Zhao, Yangying; Chu, Huaqiang; Zhou, Xuefei; Dong, Bingzhi

2014-01-01

The diatomite dynamic membrane (DDM) was utilized to dewater Chlorella pyrenoidosa of 2 g dry weight/L under continuous-flow mode, whose ultimate algae concentration ranged from 43 g to 22 g dry weight/L of different culture time. The stable flux of DDM could reach 30 L/m(2) h over a 24 h operation time without backwash. Influences of extracellular organic matters (EOM) on filtration behavior and membrane fouling were studied. The DDM was divided into three sub-layers, the slime layer, the algae layer and the diatomite layer from the outside to the inside of the cake layer based on components and morphologies. It was found that EOM caused membrane fouling by accumulating in the slime and algae layers. The DDM intercepted polysaccharides, protein-like substances, humic-like substances and some low-MW organics. Proteins were indicated the major membrane foulants with increased protein/polysaccharide ratio from the slime layer to the diatomite layer as culture time increased. This method could be applied to subsequent treatment of microalgae coupling technology of wastewater treatment or microalgae harvesting for producing biofuel. Copyright © 2013 Elsevier B.V. All rights reserved.

Plasma Creatinine Clearance in the Dog

ERIC Educational Resources Information Center

Frazier, Loy W.

1977-01-01

Lists materials and methods for an experiment that demonstrates the concept of glomerular filtration rate (GFR) using anesthesized dogs. In the dog, GFR is equivalent to the renal plasma clearance of exogenous creatinine. (CS)

Natural inactivation of Escherichia coli in anoxic and reduced groundwater

USGS Publications Warehouse

Lisle, John T.

2016-01-01

Aquifer recharge zones with geochemical characteristics observed in this study complement above ground engineered processes (e.g., filtration, disinfection), while increasing the overall indicator microorganism log-reduction rate of a facility.

Unilateral improvement in glomerular filtration rate after permanent drainage of a perinephric pseudocyst in a cat.

PubMed

McCord, Kelly; Steyn, Philip F; Lunn, Katharine F

2008-07-01

A 12-year-old, 6 kg, castrated male Siamese-cross cat was referred for investigation of an abdominal mass. The cat was found to have a left perinephric pseudocyst (PNP), accompanied by azotemia, with a small right kidney detected on ultrasound. Glomerular filtration rate (GFR) was determined by renal scintigraphy and was found to be low, with the left kidney contributing 64% of the total GFR. Percutaneous ultrasound-guided drainage of the PNP did not improve the GFR, and fluid reaccumulated within a short period of time. Laparoscopic fenestration of the cyst capsule was performed to allow for permanent drainage. The PNP did not recur, renal values progressively improved, and 8 months after the capsulotomy the GFR of the left kidney had increased by 50%, while renal function remained static on the right side.

Serum Creatinine: Not So Simple!

PubMed

Delanaye, Pierre; Cavalier, Etienne; Pottel, Hans

2017-01-01

Measuring serum creatinine is cheap and commonly done in daily practice. However, interpretation of serum creatinine results is not always easy. In this review, we will briefly remind the physiological limitations of serum creatinine due notably to its tubular secretion and the influence of muscular mass or protein intake on its concentration. We mainly focus on the analytical limitations of serum creatinine, insisting on important concept such as reference intervals, standardization (and IDMS traceability), analytical interferences, analytical coefficient of variation (CV), biological CV and critical difference. Because the relationship between serum creatinine and glomerular filtration rate is hyperbolic, all these CVs will impact not only the precision of serum creatinine but still more the precision of different creatinine-based equations, especially in low or normal-low creatinine levels (or high or normal-high glomerular filtration rate range). © 2017 S. Karger AG, Basel.

Glomerular hemodynamic alterations during acute hyperinsulinemia in normal and diabetic rats

NASA Technical Reports Server (NTRS)

Tucker, B. J.; Anderson, C. M.; Thies, R. S.; Collins, R. C.; Blantz, R. C.

1992-01-01

Treatment of insulin dependent diabetes invariably requires exogenous insulin to control blood glucose. Insulin treatment, independent of other factors associated with insulin dependent diabetes, may induce changes that affect glomerular function. Due to exogenous delivery of insulin in insulin dependent diabetes entering systemic circulation prior to the portal vein, plasma levels of insulin are often in excess of that observed in non-diabetics. The specific effects of hyperinsulinemia on glomerular hemodynamics have not been previously examined. Micropuncture studies were performed in control (non-diabetic), untreated diabetic and insulin-treated diabetic rats 7 to 10 days after administration of 65 mg/kg body weight streptozotocin. After the first period micropuncture measurements were obtained, 5 U of regular insulin (Humulin-R) was infused i.v., and glucose clamped at euglycemic values (80 to 120 mg/dl). Blood glucose concentration in non-diabetic controls was 99 +/- 6 mg/dl. In control rats, insulin infusion and glucose clamp increased nephron filtration rate due to decreases in both afferent and efferent arteriolar resistance (afferent greater than efferent) resulting in increased plasma flow and increased glomerular hydrostatic pressure gradient. However, insulin infusion and glucose clamp produced the opposite effect in both untreated and insulin-treated diabetic rats with afferent arteriolar vasoconstriction resulting in decreases in plasma flow, glomerular hydrostatic pressure gradient and nephron filtration rate. Thromboxane A2 (TX) synthetase inhibition partially decreased the vasoconstrictive response due to acute insulin infusion in diabetic rats preventing the decrease in nephron filtration rate.(ABSTRACT TRUNCATED AT 250 WORDS).

Predicting the size-dependent tissue accumulation of agents released from vascular targeted nanoconstructs

NASA Astrophysics Data System (ADS)

de Tullio, Marco D.; Singh, Jaykrishna; Pascazio, Giuseppe; Decuzzi, Paolo

2014-03-01

Vascular targeted nanoparticles have been developed for the delivery of therapeutic and imaging agents in cancer and cardiovascular diseases. However, at authors' knowledge, a comprehensive systematic analysis on their delivery efficiency is still missing. Here, a computational model is developed to predict the vessel wall accumulation of agents released from vascular targeted nanoconstructs. The transport problem for the released agent is solved using a finite volume scheme in terms of three governing parameters: the local wall shear rate , ranging from to ; the wall filtration velocity , varying from to ; and the agent diffusion coefficient , ranging from to . It is shown that the percentage of released agent adsorbing on the vessel walls in the vicinity of the vascular targeted nanoconstructs reduces with an increase in shear rate , and with a decrease in filtration velocity and agent diffusivity . In particular, in tumor microvessels, characterized by lower shear rates () and higher filtration velocities (), an agent with a diffusivity (i.e. a 50 nm particle) is predicted to deposit on the vessel wall up to of the total released dose. Differently, drug molecules, exhibiting a smaller size and much higher diffusion coefficient (), are predicted to accumulate up to . In healthy vessels, characterized by higher and lower , the largest majority of the released agent is redistributed directly in the circulation. These data suggest that drug molecules and small nanoparticles only can be efficiently released from vascular targeted nanoconstructs towards the diseased vessel walls and tissue.

Prostaglandins and nonsteroidal anti-inflammatory drugs. Effects on renal hemodynamics.

PubMed

DiBona, G F

1986-01-17

Renal prostaglandins are important modulators of renal hemodynamic function. Their synthesis from arachidonic acid precursor is regulated by neurohumoral vasoactive substances as well as by intrarenal factors. Endogenous renal prostaglandins exert little influence on renal blood flow and glomerular filtration rate in the basal state. In contrast, inhibition of cyclooxygenase-dependent arachidonic acid metabolism with nonsteroidal anti-inflammatory drugs in states of decreased renal perfusion causes marked alterations in these variables. Thus, clinical states characterized by decreased intravascular volume (decreased effective blood volume) with decreased renal perfusion augment the activity of various neurohumoral vasoactive systems and result in an increased dependence of renal hemodynamics on endogenous renal prostaglandin synthesis, which is stimulated, in a compensatory manner, by these same systems. The development of newer drugs that undergo biotransformation in the kidney between active and inactive forms may permit a lesser degree of renal cyclooxygenase inhibition, with the possibility of a reduction in the adverse effects on renal blood flow and glomerular filtration rate. Appropriate clinical use of nonsteroidal anti-inflammatory drugs requires careful consideration of the potential deleterious consequences of prostaglandin synthesis inhibition. Prostaglandins are considered to be autacoids and, as such, they exert their physiologic actions close to or at the site of synthesis. Therefore, production of prostaglandins, thromboxanes, and, possibly, leukotrienes in the renal cortex by the constituent cells of the glomeruli and the arterioles would be anticipated to influence their hemodynamic functions, that is, glomerular filtration rate, renal blood flow, renal vascular resistance, and juxtaglomerular granular cell renin release.

Glomerular Filtration Rate is Unchanged By Ultramarathon.

PubMed

Wołyniec, Wojciech; Ratkowski, Wojciech; Kasprowicz, Katarzyna; Jastrzębski, Zbigniew; Małgorzewicz, Sylwia; Witek, Konrad; Grzywacz, Tomasz; Żmijewski, Piotr; Renke, Marcin

2017-12-27

Acute kidney injury (AKI) is reported as a common complication of marathon and ultramarathon running. In previous studies AKI was diagnosed on the basis of the creatinine level in serum and estimated glomerular filtration rate (eGFR). In the present study we calculated eGFR and also measured creatinine clearance after every 25 km of a 100 km run. 20 healthy, amateur runners (males, mean age 40.75 ± 7.15 years, mean weight 76.87 ± 8.39 kg) took part in a 100 km run on a track. Blood and urine were collected before the run, after every 25 km and 12 hours after the run. 17 runners completed the study. There was increase in creatinine, urea and uric acid observed after 100 km (p < 0.05). The mean increase in creatinine was 0.21 mg/dl (24.53%). 5 runners fulfilled the Acute Kidney Injury Network (AKIN) criteria of AKI. The eGFR according to the MDRD (modification of diet in renal disease), CKD-EPI (chronic kidney disease epidemiology collaboration) and Cockcroft-Gault formulas was significantly decreased after the run (p < 0.05). Otherwise, creatinine clearance calculated from creatinine level in both serum and urine remained stable. In contrast to the majority of previous studies, we did not observe any decrease in the kidney function during an ultramarathon. In this study the creatinine clearance, which is the best routine laboratory method to determine glomerular filtration rate was used. There is no evidence that long running is harmful for kidney.

CYANOBACTERIA PASSAGE THROUGH DRINKING WATER FILTERS DURING PERTURBATION EPISODES AS A FUNCTION OF CELL MORPHOLOGY, COAGULANT AND INITIAL FILTER LOADING RATE

EPA Science Inventory

Eight pilot-scale in-line filtration trials were performed to evaluate the passage of cyanobacterial cells through drinking water filters after sudden increases in hydraulic loading rates. Trials were performed at 30 degrees C using two coagulant combinations (aluminum sulfate a...

Development of a dialyzer with enhanced internal filtration to increase the clearance of low molecular weight proteins.

PubMed

Fujimura, Takayasu; Uchi, Yukihiko; Fukuda, Makoto; Miyazaki, Miwa; Uezumi, Satoshi; Hiyoshi, Tatsuo

2004-01-01

Accumulated low molecular weight proteins in hemodialysis patients require a high-flux dialyzer. There have been several methods proposed for enhancing internal filtration, including narrowing the inside diameter of the hollow fibers, lengthening the fibers, and increasing the fiber density ratio. We tried to enhance the internal filtration by increasing the pressure drop in the dialysate compartment through increasing the fiber density ratio. If the fiber density ratio is too high, however, an irregular dialysate path may result, thus decreasing dialysis performance. Therefore, we took note of the shape of the inner housing and added a short taper structure, which improved the dialysate path dramatically. Consequently, we developed an internal filtration-enhanced dialyzer (APS-Prototype) to improve dialysis performance. The internal filtration rate in water (measured by Doppler ultrasound) was 13.2 l/session for the APS-Prototype and 5.3 l/session for the APS-15E. The amount of alpha1-microglobulin (alpha1-MG) in bovine plasma was 0.34 g for the APS-Prototype and 0.11 g for the APS-15E. In addition, the amount of alpha1-MG in vivo was 29.0% +/- 5.8% for the APS-Prototype, significantly higher than that for the APS-15E (13.6% +/- 1.9%). The desirable loss of albumin is 2-4 g in hemodiafiltration, and it was 3.92 +/- 1.03 g for the APS-Prototype. The prototype showed excellent solute removal performance with no clinical or engineering problems.

Hydrous iron oxide modified diatomite as an active filtration medium for phosphate capture.

PubMed

Wang, Zhe; Lin, Yan; Wu, Deyi; Kong, Hainan

2016-02-01

A simple method to functionalize diatomite with hydrous iron oxide was attempted and its performance as a new active filtration material to remove and recover phosphate from water was investigated under varying solution conditions. The Langmuir phosphate adsorption capacity increased from 0.6 mgP/g for raw diatomite to 4.89, 14.71, 25.02 mgP/g for hydrous iron oxide modified diatomite (HIOMD), depending on the amount of iron loaded. Loading of hydrous iron oxide caused the increase in true and bulk density and a decline in filtration rate, but to a lesser extent. It was shown that the HIOMD product with suitable iron content could retain a good filtration performance with a greatly increased adsorption capacity for phosphate. The phosphate adsorption increased by decreasing pH and by increasing ionic strength at high pH levels. The adsorption process was interpreted by ligand exchange. Coexisting oxyanions of sulfate, nitrate, citrate, carbonate, silicate and humic acid showed different effects on phosphate fixation but it was presumed that their influence at their concentrations and pH levels commonly encountered in effluent or natural waters was limited, i.e., HIOMD had a reasonably good selectivity. Results in repeated adsorption, desorption and regeneration experiment showed that the adsorbed phosphate could be recovered and the material could be reused after regeneration. The column test showed that HIOMD could be potentially utilized as an adsorption filtration medium for phosphate removal and recovery from water. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Urban non-point source pollution control by runoff retention and filtration pilot system].

PubMed

Bai, Yao; Zuo, Jian-E; Gan, Li-Li; Low, Thong Soon; Miao, Heng-Feng; Ruan, Wen-Quan; Huang, Xia

2011-09-01

A runoff retention and filtration pilot system was designed and the long-term purification effect of the runoff was monitored. Runoff pollution characters in 2 typical events and treatment effect of the pilot system were analyzed. The results showed that the runoff was severely polluted. Event mean concentrations (EMCs) of SS, COD, TN and TP in the runoff were 361, 135, 7.88 and 0.62 mg/L respectively. The runoff formed by long rain presented an obvious first flush effect. The first 25% flow contributed more than 50% of the total pollutants loading of SS, TP, DTP and PO4(3-). The pilot system could reduce 100% of the non-point source pollution if the volume of the runoff was less than the retention tank. Otherwise the overflow will be purification by the filtration pilot system and the removal rates of SS, COD, TN, TP, DTP and PO4(3-) reached 97.4% , 61.8%, 22.6%, 85.1%, 72.1%, and 85.2% respectively. The system was stable and the removal rate of SS, COD, TN, and TP were 98.6%, 65.4%, 55.1% and 92.6%. The whole system could effectively remove the non-point source pollution caused by runoff.

Omega-3 fatty acid supplementation as an adjunctive therapy in the treatment of chronic kidney disease: a meta-analysis.

PubMed

Hu, Jing; Liu, Zuoliang; Zhang, Hao

2017-01-01

The aim of this study was to evaluate the benefits and risks of omega-3 fatty acid supplementation in patients with chronic kidney disease. A systematic search of articles in PubMed, Embase, the Cochrane Library, and reference lists was performed to find relevant literature. All eligible studies assessed proteinuria, the serum creatinine clearance rate, the estimated glomerular filtration rate, or the occurrence of end-stage renal disease. Standard mean differences with 95% confidence intervals for continuous data were used to estimate the effects of omega-3 fatty acid supplementation on renal function, as reflected by the serum creatinine clearance rate, proteinuria, the estimated glomerular filtration rate, and relative risk. Additionally, a random-effects model was used to estimate the effect of omega-3 fatty acid supplementation on the risk of end-stage renal disease. Nine randomized controlled trials evaluating 444 patients with chronic kidney disease were included in the study. The follow-up duration ranged from 2 to 76.8 months. Compared with no or low-dose omega-3 fatty acid supplementation, any or high-dose omega-3 fatty acid supplementation, respectively, was associated with a lower risk of proteinuria (SMD: -0.31; 95% CI: -0.53 to -0.10; p=0.004) but had little or no effect on the serum creatinine clearance rate (SMD: 0.22; 95% CI: -0.40 to 0.84; p=0.482) or the estimated glomerular filtration rate (SMD: 0.14; 95% CI: -0.13 to 0.42; p=0.296). However, this supplementation was associated with a reduced risk of end-stage renal disease (RR: 0.49; 95% CI: 0.24 to 0.99; p=0.047). In sum, omega-3 fatty acid supplementation is associated with a significantly reduced risk of end-stage renal disease and delays the progression of this disease.

Evaluation of nano- and submicron particle penetration through ten nonwoven fabrics using a wind-driven approach.

PubMed

Gao, Pengfei; Jaques, Peter A; Hsiao, Ta-Chih; Shepherd, Angie; Eimer, Benjamin C; Yang, Mengshi; Miller, Adam; Gupta, Bhupender; Shaffer, Ronald

2011-01-01

Existing face mask and respirator test methods draw particles through materials under vacuum to measure particle penetration. However, these filtration-based methods may not simulate conditions under which protective clothing operates in the workplace, where airborne particles are primarily driven by wind and other factors instead of being limited to a downstream vacuum. This study was focused on the design and characterization of a method simulating typical wind-driven conditions for evaluating the performance of materials used in the construction of protective clothing. Ten nonwoven fabrics were selected, and physical properties including fiber diameter, fabric thickness, air permeability, porosity, pore volume, and pore size were determined. Each fabric was sealed flat across the wide opening of a cone-shaped penetration cell that was then housed in a recirculation aerosol wind tunnel. The flow rate naturally driven by wind through the fabric was measured, and the sampling flow rate of the Scanning Mobility Particle Sizer used to measure the downstream particle size distribution and concentrations was then adjusted to minimize filtration effects. Particle penetration levels were measured under different face velocities by the wind-driven method and compared with a filtration-based method using the TSI 3160 automated filter tester. The experimental results show that particle penetration increased with increasing face velocity, and penetration also increased with increasing particle size up to about 300 to 500 nm. Penetrations measured by the wind-driven method were lower than those obtained with the filtration method for most of the fabrics selected, and the relative penetration performances of the fabrics were very different due to the vastly different pore structures.

Addition of vitamin D reverses the decline in GFR following treatment with ACE inhibitors/angiotensin receptor blockers in patients with chronic kidney disease.

PubMed

Soares, Abel Esteves; Maes, Michael; Godeny, Paula; Matsumoto, Andressa Keiko; Barbosa, Décio Sabbatini; da Silva, Taysa Antonia F; Souza, Flávio Henrique M O; Delfino, Vinicius Daher Alvares

2017-12-15

Vitamin D has anti-inflammatory, anti-fibrotic effect, and may block the intrarenal renin-angiotensin system. Adequate vitamin D levels in conjunction with the use of Angiotensin-converting Enzyme Inhibitors/Angiotensin Receptor Blockers may help to slow down chronic kidney disease progression. To study a possible beneficial effect of vitamin D supplementation in chronic kidney disease patients using angiotensin-converting enzyme inhibitors/angiotensin receptor blockers on chronic kidney disease progression we performed a clinical study involving vitamin D supplementation in patients with deficiency of this vitamin. This study was conducted in two chronic kidney disease clinics in the city of Londrina, Brazil, from October 2010 to December 2012. It was involved stage 3 and 4 chronic kidney disease (estimated glomerular filtration rate between 60 and 15mL/min/1.73m 2 ) patients with and without vitamin D deficiency. The patients ingested six-month cholecalciferol 50,000IU oral supplementation to chronic kidney disease patients with vitamin D deficiency. We hypothesize changes in estimated glomerular filtration rate over study period. Our data demonstrate reservation of estimated glomerular filtration with cholecalciferol supplementation to chronic kidney disease patients taking angiotensin-converting enzyme inhibitors/angiotensin receptor blockers. The combination treatment of angiotensin converting enzyme inhibitors/angiotensin receptor blockers with cholecalciferol prevents the decline in estimated glomerular filtration in patients with chronic kidney disease following treatment with angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and may represent a valid approach to reduce renal disease progression in chronic kidney disease patients with vitamin D deficiency. This result needs confirmation in prospective controlled clinical trials. Copyright © 2017. Published by Elsevier Inc.

Measured glomerular filtration rate does not improve prediction of mortality by cystatin C and creatinine.

PubMed

Sundin, Per-Ola; Sjöström, Per; Jones, Ian; Olsson, Lovisa A; Udumyan, Ruzan; Grubb, Anders; Lindström, Veronica; Montgomery, Scott

2017-04-01

Cystatin C may add explanatory power for associations with mortality in combination with other filtration markers, possibly indicating pathways other than glomerular filtration rate (GFR). However, this has not been firmly established since interpretation of associations independent of measured GFR (mGFR) is limited by potential multicollinearity between markers of GFR. The primary aim of this study was to assess associations between cystatin C and mortality, independent of mGFR. A secondary aim was to evaluate the utility of combining cystatin C and creatinine to predict mortality risk. Cox regression was used to assess the associations of cystatin C and creatinine with mortality in 1157 individuals referred for assessment of plasma clearance of iohexol. Since cystatin C and creatinine are inversely related to mGFR, cystatin C - 1 and creatinine - 1 were used. After adjustment for mGFR, lower cystatin C - 1 (higher cystatin C concentration) and higher creatinine - 1 (lower creatinine concentration) were independently associated with increased mortality. When nested models were compared, avoiding the potential influence of multicollinearity, the independence of the associations was supported. Among models combining the markers of GFR, adjusted for demographic factors and comorbidity, cystatin C - 1 and creatinine - 1 combined explained the largest proportion of variance in associations with mortality risk ( R 2  = 0.61). Addition of mGFR did not improve the model. Our results suggest that both creatinine and cystatin C have independent associations with mortality not explained entirely by mGFR and that mGFR does not offer a more precise mortality risk assessment than these endogenous filtration markers combined. © The Author 2017. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

Glomerular filtration rate

MedlinePlus

... Some labs use different measurements or test different samples. Talk to your doctor about the meaning of your specific test results. What Abnormal Results Mean Levels below 60 mL/min/1.73 m 2 for 3 or more months ...

Nephrogenous Cyclic Adenosine Monophosphate as a Parathyroid Function Test

PubMed Central

Broadus, Arthur E.; Mahaffey, Jane E.; Bartter, Frederic C.; Neer, Robert M.

1977-01-01

Nephrogenous cyclic AMP (NcAMP), total cyclic AMP excretion (UcAMP), and plasma immunoreactive parathyroid hormone (iPTH), determined with a multivalent antiserum, were prospectively measured in 55 control subjects, 57 patients with primary hyperparathyroidism (1°HPT), and 10 patients with chronic hypoparathyroidism. In the group with 1° HPT, NcAMP was elevated in 52 patients (91%), and similar elevations were noted in subgroups of 26 patients with mild (serum calcium ≤10.7 mg/dl) or intermittent hypercalcemia, 19 patients with mild renal insufficiency (mean glomerular filtration rate, 64 ml/min), and 10 patients with moderate renal insufficiency (mean glomerular filtration rate, 43 ml/min). Plasma iPTH was increased in 41 patients (73%). The development of a parametric expression for UcAMP was found to be critically important in the clinical interpretation of results for total cAMP excretion. Because of renal impairment in a large number of patients, the absolute excretion rate of cAMP correlated poorly with the hyperparathyroid state. Expressed as a function of creatinine excretion, UcAMP was elevated in 81% of patients with 1° HPT, but the nonparametric nature of the expression led to a number of interpretive difficulties. The expression of cAMP excretion as a function of glomerular filtration rate was developed on the basis of the unique features of cAMP clearance in man, and this expression, which provided elevated values in 51 (89%) of the patients with 1° HPT, avoided entirely the inadequacies of alternative expressions. Results for NcAMP and UcAMP in nonazotemic and azotemic patients with hypoparathyroidism confirmed the validity of the measurements and the expressions employed. PMID:197123

Achieving high convection volumes in postdilution online hemodiafiltration: a prospective multicenter study

PubMed Central

Chapdelaine, Isabelle; Nubé, Menso J; Blankestijn, Peter J; Bots, Michiel L; Konings, Constantijn J A M; Kremer Hovinga, Ton K; Molenaar, Femke M; van der Weerd, Neelke C; Grooteman, Muriel P C

2017-01-01

Abstract Background. Available evidence suggests a reduced mortality risk for patients treated with high-volume postdilution hemodiafiltration (HDF) when compared with hemodialysis (HD) patients. As the magnitude of the convection volume depends on treatment-related factors rather than patient-related characteristics, we prospectively investigated whether a high convection volume (defined as ≥22 L/session) is feasible in the majority of patients (>75%). Methods. A multicenter study was performed in adult prevalent dialysis patients. Nonparticipating eligible patients formed the control group. Using a stepwise protocol, treatment time (up to 4 hours), blood flow rate (up to 400 mL/min) and filtration fraction (up to 33%) were optimized as much as possible. The convection volume was determined at the end of this optimization phase and at 4 and 8 weeks thereafter. Results. Baseline characteristics were comparable in participants (n = 86) and controls (n = 58). At the end of the optimization and 8 weeks thereafter, 71/86 (83%) and 66/83 (80%) of the patients achieved high-volume HDF (mean 25.5 ± 3.6 and 26.0 ± 3.4 L/session, respectively). While treatment time remained unaltered, mean blood flow rate increased by 27% and filtration fraction increased by 23%. Patients with <22 L/session had a higher percentage of central venous catheters (CVCs), a shorter treatment time and lower blood flow rate when compared with patients with ≥22 L/session. Conclusions. High-volume HDF is feasible in a clear majority of dialysis patients. Since none of the patients agreed to increase treatment time, these findings indicate that high-volume HDF is feasible just by increasing blood flow rate and filtration fraction. PMID:29225810

Hydrodynamics of the Fluid Filtrate on Drilling-In

NASA Astrophysics Data System (ADS)

Abbasov, É. M.; Agaeva, N. A.

2014-01-01

The volume of the liquid penetrating into the formation after drilling-in has been determined on the basis of theoretical investigations. The dynamics of change in the bottom-hole pressure has been determined in this process. It has been shown that because of the water hammer, the bottom-hole pressure can be doubled in the presence of large fractures and pores closer to the well-bottom zone.

Fully automatic region of interest selection in glomerular filtration rate estimation from 99mTc-DTPA renogram.

PubMed

Lin, Kun-Ju; Huang, Jia-Yann; Chen, Yung-Sheng

2011-12-01

Glomerular filtration rate (GFR) is a common accepted standard estimation of renal function. Gamma camera-based methods for estimating renal uptake of (99m)Tc-diethylenetriaminepentaacetic acid (DTPA) without blood or urine sampling have been widely used. Of these, the method introduced by Gates has been the most common method. Currently, most of gamma cameras are equipped with a commercial program for GFR determination, a semi-quantitative analysis by manually drawing region of interest (ROI) over each kidney. Then, the GFR value can be computed from the scintigraphic determination of (99m)Tc-DTPA uptake within the kidney automatically. Delineating the kidney area is difficult when applying a fixed threshold value. Moreover, hand-drawn ROIs are tedious, time consuming, and dependent highly on operator skill. Thus, we developed a fully automatic renal ROI estimation system based on the temporal changes in intensity counts, intensity-pair distribution image contrast enhancement method, adaptive thresholding, and morphological operations that can locate the kidney area and obtain the GFR value from a (99m)Tc-DTPA renogram. To evaluate the performance of the proposed approach, 30 clinical dynamic renograms were introduced. The fully automatic approach failed in one patient with very poor renal function. Four patients had a unilateral kidney, and the others had bilateral kidneys. The automatic contours from the remaining 54 kidneys were compared with the contours of manual drawing. The 54 kidneys were included for area error and boundary error analyses. There was high correlation between two physicians' manual contours and the contours obtained by our approach. For area error analysis, the mean true positive area overlap is 91%, the mean false negative is 13.4%, and the mean false positive is 9.3%. The boundary error is 1.6 pixels. The GFR calculated using this automatic computer-aided approach is reproducible and may be applied to help nuclear medicine physicians in clinical practice.

Removal of humic acid by a new type of electrical hollow-fiber microfiltration (E-HFMF)

NASA Astrophysics Data System (ADS)

Shang, Ran; Deng, Hui-ping; Hu, Jing-yi

2010-11-01

Low pressure membrane filtration, such as microfiltration, was widely used in the field of drinking water purification in the past few decades. Traditional microfiltration membranes are not efficient enough in the removal of natural organic matters (NOM) from raw water. Moreover, they tend to be fouled by the NOM and the filtration age of the membranes is thus shrinked. To tackle these problems, a new type of electrical hollow-fiber microfiltration module (E-HFMF) was designed. In the E-HFMF module, the hollow-fiber microfiltration membranes were placed into the radialized electrical field which functioned from the centre to the exterior of the cylindrical cavity. The main goal of the present study was to evaluate the efficiency of E-HFMF to remove the humic acid (HA, one of the main components of NOM). According to the parallel tests compared with the traditional microfiltration, the removal rate of humic acid was raised to 70%˜85% in terms of UV-254 and to 60%˜75% in terms of DOC when filtrating with the E-HFMF, while the removal rates of humic acid were 10%˜20% and 1%˜10% respectively when filtrating with the traditional microfiltration. The negative charged humic acid moved to the anode because of the electrophoresis, so few humic acid could be able to permeate through the membrane. The electrophoresis mobility of the humic acid permeating through the traditional microfiltration decreased by 19%, while the same index from the E-HFMF decreased by 75%. This indicated that the electrophoresis played a significant role on removing the humic acid. According to the gel permeate chromatograph analysis, humic acid aggregated in an electric field and thus forms loose and permeable cake layer on the membrane surface, which also relieved membrane fouling. Meanwhile, the negative charged humic acid migrating to the anode at the center minimized the deposition onto the membrane surface, and eliminated the membrane fouling as a result. During the E-HFMF filtration, the humic acid was not oxidized observably in the electrical field, according to the FT-IR analysis.

Aging and physiological changes of the kidneys including changes in glomerular filtration rate.

PubMed

Musso, Carlos G; Oreopoulos, Dimitrios G

2011-01-01

In addition to the structural changes in the kidney associated with aging, physiological changes in renal function are also found in older adults, such as decreased glomerular filtration rate, vascular dysautonomia, altered tubular handling of creatinine, reduction in sodium reabsorption and potassium secretion, and diminished renal reserve. These alterations make aged individuals susceptible to the development of clinical conditions in response to usual stimuli that would otherwise be compensated for in younger individuals, including acute kidney injury, volume depletion and overload, disorders of serum sodium and potassium concentration, and toxic reactions to water-soluble drugs excreted by the kidneys. Additionally, the preservation with aging of a normal urinalysis, normal serum urea and creatinine values, erythropoietin synthesis, and normal phosphorus, calcium and magnesium tubular handling distinguishes decreased GFR due to normal aging from that due to chronic kidney disease. Copyright © 2011 S. Karger AG, Basel.

Virus removal by unsaturated wastewater filtration: effects of biofilm accumulation and hydrophobicity.

PubMed

Heistad, A; Scott, T; Skaarer, A M; Seidu, R; Hanssen, J F; Stenström, T A

2009-01-01

Enhanced treatment of septic tank effluent can improve the hydraulic function and performance of infiltration systems and constructed wetlands. By intermittent spray application of septic tank effluent onto a coarse-grained filter media, an unsaturated flow regime beneficial for pathogen removal is created. A column filtration study showed an increase in PRD-1 removal by time of operation with corresponding biofilm accumulation in the filter material. The same increased removal was observed for 1 mum polystyrene beads, irrespective of their hydrophilic/hydrophobic surface properties. A control experiment with sorption of 1 mum hydrophobic and hydrophilic polystyrene beads to different glass surfaces with hydrophobic and hydrophilic properties indicate that mechanisms other than hydrophobic interactions may govern the rate of attachment to the filter media. For a given volumetric flow-rate in the columns, the presence of biofilm altered the hydrodynamic characteristics and this resulted in increased retention time and particle removal.

Iron and manganese removal: Recent advances in modelling treatment efficiency by rapid sand filtration.

PubMed

Vries, D; Bertelkamp, C; Schoonenberg Kegel, F; Hofs, B; Dusseldorp, J; Bruins, J H; de Vet, W; van den Akker, B

2017-02-01

A model has been developed that takes into account the main characteristics of (submerged) rapid filtration: the water quality parameters of the influent water, notably pH, iron(II) and manganese(II) concentrations, homogeneous oxidation in the supernatant layer, surface sorption and heterogeneous oxidation kinetics in the filter, and filter media adsorption characteristics. Simplifying assumptions are made to enable validation in practice, while maintaining the main mechanisms involved in iron(II) and manganese(II) removal. Adsorption isotherm data collected from different Dutch treatment sites show that Fe(II)/Mn(II) adsorption may vary substantially between them, but generally increases with higher pH. The model is sensitive to (experimentally) determined adsorption parameters and the heterogeneous oxidation rate. Model results coincide with experimental values when the heterogeneous rate constants are calibrated. Copyright © 2016 Elsevier Ltd. All rights reserved.

Relationship of glomerular filtration rate based on serum iodixanol clearance to IRIS staging in cats with chronic kidney disease.

PubMed

Iwama, Ryosuke; Sato, Tsubasa; Katayama, Masaaki; Shimamura, Shunsuke; Satoh, Hiroshi; Ichijo, Toshihiro; Furuhama, Kazuhisa

2015-08-01

We examined the correlation between the glomerular filtration rate (GFR) estimated from an equation based on the serum iodixanol clearance technique and International Renal Interest Society (IRIS) stages of chronic kidney disease (CKD) in cats. The equation included the injection dose, sampling time, serum concentration and estimated volume of distribution (Vd) of the isotonic, nonionic, contrast medium iodixanol as a test tracer. The percent changes in the median basal GFR values calculated from the equation in CKD cats resembled those of IRIS stages 1-3. These data validate the association between the GFR derived from the simplified equation and IRIS stages based on the serum creatinine concentration in cats with CKD. They describe the GFR ranges determined using single-sample iodixanol clearance for healthy cats and cats with various IRIS stages of CKD.

Autonomous water sampling for long-term monitoring of trace metals in remote environments.

PubMed

Kim, Hyojin; Bishop, James K B; Wood, Todd J; Fung, Inez Y

2012-10-16

A remotely controlled autonomous method for long-term high-frequency sampling of environmental waters in remote locations is described. The method which preserves sample integrity of dissolved trace metals and major ions for month-long periods employs a gravitational filtration system (GFS) that separates dissolved and particulate phases as samples are collected. The key elements of GFS are (1) a modified "air-outlet" filter holder to maximize filtration rate and thus minimize filtration artifacts; and (2) the direct delivery of filtrate to dedicated bottle sets for specific analytes. Depth and screen filter types were evaluated with depth filters showing best performance. GFS performance is validated using ground, stream, and estuary waters. Over 30 days of storage, samples with GFS treatment had average recoveries of 95 ± 19% and 105 ± 7% of Fe and Mn, respectively; without GFS treatment, average recoveries were only 16% and 18%. Dissolved major cations K, Mg, and Na were stable independent of collection methodology, whereas Ca in some groundwater samples decreased up to 42% without GFS due to CaCO(3) precipitation. In-field performance of GFS equipped autosamplers is demonstrated using ground and streamwater samples collected at the Angelo Coast Range Reserve, California from October 3 to November 4 2011.

Water Filtration Using Plant Xylem

PubMed Central

Chambers, Valerie; Venkatesh, Varsha; Karnik, Rohit

2014-01-01

Effective point-of-use devices for providing safe drinking water are urgently needed to reduce the global burden of waterborne disease. Here we show that plant xylem from the sapwood of coniferous trees – a readily available, inexpensive, biodegradable, and disposable material – can remove bacteria from water by simple pressure-driven filtration. Approximately 3 cm3 of sapwood can filter water at the rate of several liters per day, sufficient to meet the clean drinking water needs of one person. The results demonstrate the potential of plant xylem to address the need for pathogen-free drinking water in developing countries and resource-limited settings. PMID:24587134

Recalibrated Equations for Determining Effect of Oil Filtration on Rolling Bearing Life

NASA Technical Reports Server (NTRS)

Needelman, William M.; Zaretsky, Erwin V.

2014-01-01

In 1991, Needelman and Zaretsky presented a set of empirically derived equations for bearing fatigue life (adjustment) factors (LFs) as a function of oil filter ratings. These equations for life factors were incorporated into the reference book, "STLE Life Factors for Rolling Bearings." These equations were normalized (LF = 1) to a 10-micrometer filter rating at Beta(sub x) = 200 (normal cleanliness) as it was then defined. Over the past 20 years, these life factors based on oil filtration have been used in conjunction with ANSI/ABMA standards and bearing computer codes to predict rolling bearing life. Also, additional experimental studies have been made by other investigators into the relationship between rolling bearing life and the size, number, and type of particle contamination. During this time period filter ratings have also been revised and improved, and they now use particle counting calibrated to a new National Institute of Standards and Technology (NIST) reference material, NIST SRM 2806, 1997. This paper reviews the relevant bearing life studies and describes the new filter ratings. New filter ratings, Beta(sub x(c)) = 200 and Beta(sub x(c)) = 1000, are benchmarked to old filter ratings, Beta(sub x) = 200, and vice versa. Two separate sets of filter LF values were derived based on the new filter ratings for roller bearings and ball bearings, respectively. Filter LFs can be calculated for the new filter ratings.

Decomposition of lignin and cellobiose in relation to the enzymatic hydrolysis of cellulose

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamanaka, Y.; Carroad, P.A.; Riaz, M.

1977-02-01

Studies are reported on the use of fungal ..beta..-glucosidase in conjunction with Trichoderma viride cellulase and the search for an effective enzyme system for lignin degradation. ..beta..-glucosidase is of potential benefit in cellulose hydrolysis by catalyzing the hydrolysis of cellobiose to glucose thereby reducing product inhibition and producing a higher glucose yield. Removal of lignin from cellulosic material makes the cellulose more accessible to hydrolyzing enzymes. Hydrolysis studies on Solka Floc and newsprint were conducted with T. viride filtrates containing various proportions of B. theobromae filtrates. Significant improvement in hydrolysis rate particularly in glucose content was obtained by thus enrichingmore » the ..beta..-glucosidase content of the cellulase. In the search for a lignin degrading enzyme, major emphasis was given to the fungus Polyporous versicolor. Significant o-diphenol oxidoreductase (catecholase) activity was found in the culture filtrates. Preliminary observations of a surface culture of the fungus in a composting mode suggest that delignification may be obtained in this manner. Work is continuing on this.« less

Universal and reusable virus deactivation system for respiratory protection

NASA Astrophysics Data System (ADS)

Quan, Fu-Shi; Rubino, Ilaria; Lee, Su-Hwa; Koch, Brendan; Choi, Hyo-Jick

2017-01-01

Aerosolized pathogens are a leading cause of respiratory infection and transmission. Currently used protective measures pose potential risk of primary/secondary infection and transmission. Here, we report the development of a universal, reusable virus deactivation system by functionalization of the main fibrous filtration unit of surgical mask with sodium chloride salt. The salt coating on the fiber surface dissolves upon exposure to virus aerosols and recrystallizes during drying, destroying the pathogens. When tested with tightly sealed sides, salt-coated filters showed remarkably higher filtration efficiency than conventional mask filtration layer, and 100% survival rate was observed in mice infected with virus penetrated through salt-coated filters. Viruses captured on salt-coated filters exhibited rapid infectivity loss compared to gradual decrease on bare filters. Salt-coated filters proved highly effective in deactivating influenza viruses regardless of subtypes and following storage in harsh environmental conditions. Our results can be applied in obtaining a broad-spectrum, airborne pathogen prevention device in preparation for epidemic and pandemic of respiratory diseases.

Universal and reusable virus deactivation system for respiratory protection

PubMed Central

Quan, Fu-Shi; Rubino, Ilaria; Lee, Su-Hwa; Koch, Brendan; Choi, Hyo-Jick

2017-01-01

Aerosolized pathogens are a leading cause of respiratory infection and transmission. Currently used protective measures pose potential risk of primary/secondary infection and transmission. Here, we report the development of a universal, reusable virus deactivation system by functionalization of the main fibrous filtration unit of surgical mask with sodium chloride salt. The salt coating on the fiber surface dissolves upon exposure to virus aerosols and recrystallizes during drying, destroying the pathogens. When tested with tightly sealed sides, salt-coated filters showed remarkably higher filtration efficiency than conventional mask filtration layer, and 100% survival rate was observed in mice infected with virus penetrated through salt-coated filters. Viruses captured on salt-coated filters exhibited rapid infectivity loss compared to gradual decrease on bare filters. Salt-coated filters proved highly effective in deactivating influenza viruses regardless of subtypes and following storage in harsh environmental conditions. Our results can be applied in obtaining a broad-spectrum, airborne pathogen prevention device in preparation for epidemic and pandemic of respiratory diseases. PMID:28051158

Reduction in cryptosporidiosis associated with introduction of enhanced filtration of drinking water at Loch Katrine, Scotland.

PubMed

Pollock, K G J; Young, D; Robertson, C; Ahmed, S; Ramsay, C N

2014-01-01

Previous evidence has suggested an association between cryptosporidiosis and consumption of unfiltered drinking water from Loch Katrine in Scotland. Before September 2007, the water was only micro-strained and chlorinated; however, since that time, coagulation and rapid gravity filtration have been installed. In order to determine risk factors associated with cryptosporidiosis, including drinking water, we analysed data on microbiologically confirmed cases of cryptosporidiosis from 2004 to 2010. We identified an association between the incidence of cryptosporidiosis and unfiltered Loch Katrine drinking water supplied to the home (odds ratio 1.86, 95% confidence interval 1.11-3.11, P = 0.019). However, while filtration appears to be associated with initially reduced rates of cryptosporidiosis, evidence suggests it may paradoxically make those consumers more susceptible to other transmission routes in the long-term. These findings support implementation of similar treatment for other unfiltered drinking-water supplies, as a means of reducing cryptosporidiosis associated with drinking water.

40 CFR 141.173 - Filtration.

Code of Federal Regulations, 2014 CFR

2014-07-01

... treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration. A public water system... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that does...

40 CFR 141.173 - Filtration.

Code of Federal Regulations, 2011 CFR

2011-07-01

... treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration. A public water system... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that does...

40 CFR 141.173 - Filtration.

Code of Federal Regulations, 2013 CFR

2013-07-01

... treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration. A public water system... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that does...

40 CFR 141.173 - Filtration.

Code of Federal Regulations, 2012 CFR

2012-07-01

... treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration. A public water system... PRIMARY DRINKING WATER REGULATIONS Enhanced Filtration and Disinfection-Systems Serving 10,000 or More People § 141.173 Filtration. A public water system subject to the requirements of this subpart that does...

Impact of mussel bioengineering on fine-grained sediment dynamics in a coastal lagoon: A numerical modelling investigation

NASA Astrophysics Data System (ADS)

Forsberg, Pernille L.; Lumborg, Ulrik; Bundgaard, Klavs; Ernstsen, Verner B.

2017-12-01

Rødsand lagoon in southeast Denmark is a non-tidal coastal lagoon. It is home to a wide range of marine flora and fauna and part of the Natura 2000 network. An increase in turbidity through elevated levels of suspended sediment concentration (SSC) within the lagoon may affect the ecosystem health due to reduced light penetration. Increasing SSC levels within Rødsand lagoon could be caused by increasing storm intensity or by a sediment spill from dredging activities west of the lagoon in relation to the planned construction of the Fehmarnbelt fixed link between Denmark and Germany. The aim of the study was to investigate the impact of a mussel reef on sediment import and SSC in a semi-enclosed lagoon through the development of a bioengineering modelling application that makes it possible to include the filtrating effect of mussels in a numerical model of the lagoonal system. The numerical implementation of an exterior mussel reef generated a reduction in the SSC in the vicinity of the reef, through the adjacent inlet and in the western part of the lagoon. The mussel reef reduced the sediment import to Rødsand lagoon by 13-22% and reduced the SSC within Rødsand lagoon by 5-9% depending on the filtration rate and the reef length. The results suggest that the implementation of a mussel reef has the potential to relieve the pressure of increasing turbidity levels within a semi-enclosed lagoonal system. However, further assessment and development of the bioengineering application and resulting ecosystem impacts are necessary prior to actual implementation.

Biodegradability of DBP precursors after drinking water ozonation.

PubMed

de Vera, Glen Andrew; Keller, Jurg; Gernjak, Wolfgang; Weinberg, Howard; Farré, Maria José

2016-12-01

Ozonation is known to generate biodegradable organic matter, which is typically reduced by biological filtration to avoid bacterial regrowth in distribution systems. Post-chlorination generates halogenated disinfection byproducts (DBPs) but little is known about the biodegradability of their precursors. This study determined the effect of ozonation and biofiltration conditions, specifically ozone exposure and empty bed contact time (EBCT), on the control of DBP formation potentials in drinking water. Ozone exposure was varied through addition of H 2 O 2 during ozonation at 1 mgO 3 /mgDOC followed by biological filtration using either activated carbon (BAC) or anthracite. Ozonation led to a 10% decrease in dissolved organic carbon (DOC), without further improvement from H 2 O 2 addition. Raising H 2 O 2 concentrations from 0 to 2 mmol/mmolO 3 resulted in increased DBP formation potentials during post-chlorination of the ozonated water (target Cl 2 residual after 24 h = 1-2 mg/L) as follows: 4 trihalomethanes (THM4, 37%), 8 haloacetic acids (HAA8, 44%), chloral hydrate (CH, 107%), 2 haloketones (HK2, 97%), 4 haloacetonitriles (HAN4, 33%), trichloroacetamide (TCAM, 43%), and adsorbable organic halogen (AOX, 27%), but a decrease in the concentrations of 2 trihalonitromethanes (THNM2, 43%). Coupling ozonation with biofiltration prior to chlorination effectively lowered the formation potentials of all DBPs including CH, HK2, and THNM2, all of which increased after ozonation. The dynamics of DBP formation potentials during BAC filtration at different EBCTs followed first-order reaction kinetics. Minimum steady-state concentrations were attained at an EBCT of about 10-20 min, depending on the DBP species. The rate of reduction in DBP formation potentials varied among individual species before reaching their minimum concentrations. CH, HK2, and THNM2 had the highest rate constants of between 0.5 and 0.6 min -1 followed by HAN4 (0.4 min -1 ), THM4 (0.3 min -1 ), HAA8 (0.2 min -1 ), and AOX (0.1 min -1 ). At an EBCT of 15 min, the reduction in formation potential for most DBPs was less than 50% but was higher than 70% for CH, HK2, and THNM2. The formation of bromine-containing DBPs increased with increasing EBCT, most likely due to an increase in Br - /DOC ratio. Overall, this study demonstrated that the combination of ozonation and biofiltration is an effective approach to mitigate DBP formation during drinking water treatment. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of slow filtration columns to assess oxygen respiration, consumption of dissolved organic carbon, nitrogen transformations, and microbial parameters in hyporheic sediments.

PubMed

Mermillod-Blondin, F; Mauclaire, L; Montuelle, B

2005-05-01

Biogeochemical processes mediated by microorganisms in river sediments (hyporheic sediments) play a key role in river metabolism. Because biogeochemical reactions in the hyporheic zone are often limited to the top few decimetres of sediments below the water-sediment interface, slow filtration columns were used in the present study to quantify biogeochemical processes (uptakes of O2, DOC, and nitrate) and the associated microbial compartment (biomass, respiratory activity, and hydrolytic activity) at a centimetre scale in heterogeneous (gravel and sand) sediments. The results indicated that slow filtration columns recreated properly the aerobic-anaerobic gradient classically observed in the hyporheic zone. O2 and NO3- consumptions (256 +/- 13 microg of O2 per hour and 14.6 +/- 6.1 microg of N-NO3- per hour) measured in columns were in the range of values measured in different river sediments. Slow filtration columns also reproduced the high heterogeneity of the hyporheic zone with the presence of anaerobic pockets in sediments where denitrification and fermentation processes occurred. The respiratory and hydrolytic activities of bacteria were strongly linked with the O2 consumption in the experimental system, highlighting the dominance of aerobic processes in our river sediments. In comparison with these activities, the bacterial biomass (protein content) integrated both aerobic and anaerobic processes and could be used as a global microbial indicator in our system. Finally, slow filtration columns are an appropriate tool to quantify in situ rates of biogeochemical processes and to determine the relationship between the microbial compartment and the physico-chemical environment in coarse river sediments.

Risk factors for requirement of filtration surgery after vitrectomy in patients with proliferative diabetic retinopathy.

PubMed

Sakamoto, Masashi; Hashimoto, Ryuya; Yoshida, Izumi; Maeno, Takatoshi

2018-01-01

We retrospectively reviewed patients with postoperative neovascular glaucoma (NVG) after vitrectomy for proliferative diabetic retinopathy to investigate how variables assessed before, during, and after vitrectomy are associated with the requirement for filtration surgery. The subjects in this retrospective, observational, comparative study were 55 consecutive patients (61 eyes) who underwent vitrectomy for proliferative diabetic retinopathy at Toho University Sakura Medical Center between December 2011 and November 2016, were followed up for at least 6 months after surgery, and developed NVG within 2 years after surgery. They comprised 44 men and 11 women of mean age 52.4±9.1 years, who were followed up for a mean 7.1±6.1 months. We collected data on the following 16 variables: sex, age, history of panretinal photocoagulation completed within 3 months before vitrectomy, presence/absence of a lens, obvious iris/angle neovascularization, tractional retinal detachment, diabetic macular edema, vitreous hemorrhage, visual acuity and intraocular pressure before vitrectomy and at the onset of NVG, glycated hemoglobin, fasting blood glucose, estimated glomerular filtration rate, and use of intraoperative gas tamponade. Logistic regression analysis with the backward elimination method identified preoperative fasting hyperglycemia ( P =0.08), high intraocular pressure at the onset of NVG ( P =0.04), and use of gas tamponade during vitrectomy ( P =0.008) to be significant risk factors for requirement of filtration surgery. Preoperative fasting hyperglycemia, high intraocular pressure at the onset of NVG, and use of gas tamponade during vitrectomy predispose patients to require filtration surgery in the event of postoperative NVG.

Bactericidal activity and silver release of porous ceramic candle filter prepared by sintering silica with silver nanoparticles/zeolite for water disinfection

NASA Astrophysics Data System (ADS)

Trinh Nguyen, Thuy Ai; Phu Dang, Van; Duy Nguyen, Ngoc; Le, Anh Quoc; Thanh Nguyen, Duc; Hien Nguyen, Quoc

2014-09-01

Porous ceramic candle filters (PCCF) were prepared by sintering silica from rice husk with silver nanoparticles (AgNPs)/zeolite A at about 1050 °C to create bactericidal PCCF/AgNPs for water disinfection. The silver content in PCCF/AgNPs was of 300-350 mg kg-1 determined by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) and the average pore size of PCCF/AgNPs was of 50-70 Å measured by Brunauer-Emmett-Teller (BET) method. The bactericidal activity and silver release of PCCF/AgNPs have been investigated by flow test with water flow rate of 5 L h-1 and initial inoculation of E. coli in inlet water of 106 CFU/100 mL. The volume of filtrated water was collected up to 500 L. Results showed that the contamination of E. coli in filtrated water was <1 CFU/100 mL and the content of silver released from PCCF/AgNPs into filtrated water was <1 μg L-1, it is low, far under the WHO guideline of 100 μg L-1 at maximum for drinking water. Based on the content of silver in PCCF/AgNPs and in filtrated water, it was estimated that one PCCF/AgNPs could be used to filtrate of ˜100 m3 water. Thus, as-prepared PCCF/AgNPs releases low content of silver into water and shows effectively bactericidal activity that is promising to apply as point-of-use water treatment technology for drinking water disinfection.

Renal blood flow using arterial spin labelling MRI and calculated filtration fraction in healthy adult kidney donors Pre-nephrectomy and post-nephrectomy.

PubMed

Cutajar, Marica; Hilton, Rachel; Olsburgh, Jonathon; Marks, Stephen D; Thomas, David L; Banks, Tina; Clark, Christopher A; Gordon, Isky

2015-08-01

Renal plasma flow (RPF) (derived from renal blood flow, RBF) and glomerular filtration rate (GFR) allow the determination of the filtration fraction (FF), which may have a role as a non-invasive renal biomarker. This is a hypothesis-generating pilot study assessing the effect of nephrectomy on renal function in healthy kidney donors. Eight living kidney donors underwent arterial spin labelling (ASL) magnetic resonance imaging (MRI) and GFR measurement prior to and 1 year after nephrectomy. Chromium-51 labelled ethylenediamine tetraacetic acid ((51)Cr-EDTA) with multi-blood sampling was undertaken and GFR calculated. The RBF and GFR obtained were used to calculate FF. All donors showed an increase in single kidney GFR of 24 - 75 %, and all but two showed an increase in FF (-7 to +52 %) after nephrectomy. The increase in RBF, and hence RPF, post-nephrectomy was not as great as the increase in GFR in seven out of eight donors. As with any pilot study, the small number of donors and their relatively narrow age range are potential limiting factors. The ability to measure RBF, and hence RPF, non-invasively, coupled with GFR measurement, allows calculation of FF, a biomarker that might provide a sensitive indicator of loss of renal reserve in potential donors. • Non-invasive MRI measured renal blood flow and calculated renal plasma flow. • Effect of nephrectomy on blood flow and filtration in donors is presented. • Calculated filtration fraction may be a useful new kidney biomarker.

Point-of-Use Removal of Cryptosporidium parvum from Water: Independent Effects of Disinfection by Silver Nanoparticles and Silver Ions and by Physical Filtration in Ceramic Porous Media.

PubMed

Abebe, Lydia S; Su, Yi-Hsuan; Guerrant, Richard L; Swami, Nathan S; Smith, James A

2015-11-03

Ceramic water filters (CWFs) impregnated with silver nanoparticles are a means of household-level water treatment. CWFs remove/deactivate microbial pathogens by employing two mechanisms: metallic disinfection and physical filtration. Herein we report on the independent effects of silver salt and nanoparticles on Cryptosporidium parvum and the removal of C. parvum by physical filtration in porous ceramic filter media. Using a murine (mouse) model, we observed that treatment of oocysts with silver nitrate and proteinate-capped silver nanoparticles resulted in decreased infection relative to untreated oocysts. Microscopy and excystation experiments were conducted to support the disinfection investigation. Heat and proteinate-capped silver-nanoparticle treatment of oocysts resulted in morphological modifications and decreased excystation rates of sporozoites. Subsequently, disk-shaped ceramic filters were produced to investigate the transport of C. parvum. Two factors were varied: sawdust size and clay-to-sawdust ratio. Five disks were prepared with combinations of 10, 16, and 20 mesh sawdust and sawdust percentage that ranged from 9 to 11%. C. parvum removal efficiencies ranged from 1.5 log (96.4%) to 2.1 log (99.2%). The 16-mesh/10% sawdust had the greatest mean reduction of 2.1-log (99.2%), though there was no statistically significant difference in removal efficiency. Based on our findings, physical filtration and silver nanoparticle disinfection likely contribute to treatment of C. parvum for silver impregnated ceramic water filters, although the contribution of physical filtration is likely greater than silver disinfection.

Alternatives for the Bedside Schwartz Equation to Estimate Glomerular Filtration Rate in Children.

PubMed

Pottel, Hans; Dubourg, Laurence; Goffin, Karolien; Delanaye, Pierre

2018-01-01

The bedside Schwartz equation has long been and still is the recommended equation to estimate glomerular filtration rate (GFR) in children. However, this equation is probably best suited to estimate GFR in children with chronic kidney disease (reduced GFR) but is not optimal for children with GFR >75 mL/min/1.73 m 2 . Moreover, the Schwartz equation requires the height of the child, information that is usually not available in the clinical laboratory. This makes automatic reporting of estimated glomerular filtration rate (eGFR) along with serum creatinine impossible. As the majority of children (even children referred to nephrology clinics) have GFR >75 mL/min/1.73 m 2 , it might be interesting to evaluate possible alternatives to the bedside Schwartz equation. The pediatric form of the Full Age Spectrum (FAS) equation offers an alternative to Schwartz, allowing automatic reporting of eGFR since height is not necessary. However, when height is involved in the FAS equation, the equation is essentially equal to the Schwartz equation for children, but there are large differences for adolescents. Combining standardized biomarkers increases the prediction performance of eGFR equations for children, reaching P10 ≈ 45% and P30 ≈ 90%. There are currently good and simple alternatives to the bedside Schwartz equation, but the more complex equations combining serum creatinine, serum cystatin C, and height show the highest accuracy and precision. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

Efficient reporting of the estimated glomerular filtration rate without height in pediatric patients with cancer.

PubMed

Jeong, Tae-Dong; Cho, Eun-Jung; Lee, Woochang; Chun, Sail; Hong, Ki-Sook; Min, Won-Ki

2017-10-26

The updated bedside Schwartz equation requires constant, serum creatinine concentration and height measurements to calculate the estimated glomerular filtration rate (eGFR) in pediatric patients. Unlike the serum creatinine levels, obtaining height information from the laboratory information system (LIS) is not always possible in a clinical laboratory. Recently, the height-independent eGFR equation, the full age spectrum (FAS) equation, has been introduced. We evaluated the performance of height-independent eGFR equation in Korean children with cancer. A total of 250 children who underwent chromium-51-ethylenediamine tetra acetic-acid (51Cr-EDTA)-based glomerular filtration rate (GFR) measurements were enrolled. The 51Cr-EDTA GFR was used as the reference GFR. The bias (eGFR - measured GFR), precision (root mean square error [RMSE]) and accuracy (P30) of the FAS equations were compared to those of the updated Schwartz equation. P30 was defined as the percentage of patients whose eGFR was within ±30% of the measured GFR. The FAS equation showed significantly lower bias (mL/min/1.73 m2) than the updated Schwartz equation (4.2 vs. 8.7, p<0.001). The RMSE and P30 were: updated Schwartz of 43.8 and 64.4%, respectively, and FAS of 42.7 and 66.8%, respectively. The height-independent eGFR-FAS equation was less biased and as accurate as the updated Schwartz equation in Korean children. The use of the height-independent eGFR equation will allow for efficient reporting of eGFR through the LIS in clinical laboratories.

Salt sensitivity of children with low birth weight.

PubMed

Simonetti, Giacomo D; Raio, Luigi; Surbek, Daniel; Nelle, Mathias; Frey, Felix J; Mohaupt, Markus G

2008-10-01

Compromised intrauterine fetal growth leading to low birth weight (<2500 g) is associated with adulthood renal and cardiovascular disease. The aim of this study was to assess the effect of salt intake on blood pressure (salt sensitivity) in children with low birth weight. White children (n=50; mean age: 11.3+/-2.1 years) born with low (n=35) or normal (n=15) birth weight and being either small or appropriate for gestational age (n=25 in each group) were investigated. The glomerular filtration rate was calculated using the Schwartz formula, and renal size was measured by ultrasound. Salt sensitivity was assigned if mean 24-hour blood pressure increased by >or=3 mm Hg on a high-salt diet as compared with a controlled-salt diet. Baseline office blood pressure was higher and glomerular filtration rate lower in children born with low birth weight as compared with children born at term with appropriate weight (P<0.05). Salt sensitivity was present in 37% and 47% of all of the low birth weight and small for gestational age children, respectively, higher even than healthy young adults from the same region. Kidney length and volume (both P<0.0001) were reduced in low birth weight children. Salt sensitivity inversely correlated with kidney length (r(2)=0.31; P=0.005) but not with glomerular filtration rate. We conclude that a reduced renal mass in growth-restricted children poses a risk for a lower renal function and for increased salt sensitivity. Whether the changes in renal growth are causative or are the consequence of the same abnormal "fetal programming" awaits clarification.

Current use of equations for estimating glomerular filtration rate in Spanish laboratories.

PubMed

Gràcia-Garcia, Sílvia; Montañés-Bermúdez, Rosario; Morales-García, Luis J; Díez-de Los Ríos, M José; Jiménez-García, Juan Á; Macías-Blanco, Carlos; Martínez-López, Rosalina; Ruiz-Altarejos, Joaquín; Ruiz-Martín, Guadalupe; Sanz-Hernández, Sonia; Ventura-Pedret, Salvador

2012-07-17

In 2006 the Spanish Society of Clinical Biochemistry and Molecular Pathology (SEQC) and the Spanish Society of Nephrology (S.E.N.) developed a consensus document in order to facilitate the diagnosis and monitoring of chronic kidney disease with the incorporation of equations for estimating glomerular filtration rate (eGFR) into laboratory reports. The current national prevalence of eGFR reporting and the degree of adherence to these recommendations among clinical laboratories is unknown. We administered a national survey in 2010-11 to Spanish clinical laboratories. The survey was through e-mail or telephone to laboratories that participated in the SEQC’s Programme for External Quality Assurance, included in the National Hospitals Catalogue 2010, including both primary care and private laboratories. A total of 281 laboratories answered to the survey. Of these, 88.2% reported on the eGFR, with 61.9% reporting on the MDRD equation and 31.6% using the MDRD-IDMS equation. A total of 42.5% of laboratories always reported serum creatinine values, and other variables only when specifically requested. Regarding the way results were presented, 46.2% of laboratories reported the exact numerical value only when the filtration rate was below 60mL/min/1.73m2, while 50.6% reported all values regardless. In 56.3% of the cases reporting eGFR, an interpretive commentary of it was enclosed. Although a high percentage of Spanish laboratories have added eGFR in their reports, this metric is not universally used. Moreover, some aspects, such as the equation used and the correct expression of eGFR results, should be improved.

Evaluation of the Effect of the Volume Throughput and Maximum Flux of Low-Surface-Tension Fluids on Bacterial Penetration of 0.2 Micron-Rated Filters during Process-Specific Filter Validation Testing.

PubMed

Folmsbee, Martha

2015-01-01

Approximately 97% of filter validation tests result in the demonstration of absolute retention of the test bacteria, and thus sterile filter validation failure is rare. However, while Brevundimonas diminuta (B. diminuta) penetration of sterilizing-grade filters is rarely detected, the observation that some fluids (such as vaccines and liposomal fluids) may lead to an increased incidence of bacterial penetration of sterilizing-grade filters by B. diminuta has been reported. The goal of the following analysis was to identify important drivers of filter validation failure in these rare cases. The identification of these drivers will hopefully serve the purpose of assisting in the design of commercial sterile filtration processes with a low risk of filter validation failure for vaccine, liposomal, and related fluids. Filter validation data for low-surface-tension fluids was collected and evaluated with regard to the effect of bacterial load (CFU/cm(2)), bacterial load rate (CFU/min/cm(2)), volume throughput (mL/cm(2)), and maximum filter flux (mL/min/cm(2)) on bacterial penetration. The data set (∼1162 individual filtrations) included all instances of process-specific filter validation failures performed at Pall Corporation, including those using other filter media, but did not include all successful retentive filter validation bacterial challenges. It was neither practical nor necessary to include all filter validation successes worldwide (Pall Corporation) to achieve the goals of this analysis. The percentage of failed filtration events for the selected total master data set was 27% (310/1162). Because it is heavily weighted with penetration events, this percentage is considerably higher than the actual rate of failed filter validations, but, as such, facilitated a close examination of the conditions that lead to filter validation failure. In agreement with our previous reports, two of the significant drivers of bacterial penetration identified were the total bacterial load and the bacterial load rate. In addition to these parameters, another three possible drivers of failure were also identified: volume throughput, maximum filter flux, and pressure. Of the data for which volume throughput information was available, 24% (249/1038) of the filtrations resulted in penetration. However, for the volume throughput range of 680-2260 mL/cm(2), only 9 out of 205 bacterial challenges (∼4%) resulted in penetration. Of the data for which flux information was available, 22% (212/946) resulted in bacterial penetration. However, in the maximum filter flux range from 7 to 18 mL/min/cm(2), only one out of 121 filtrations (0.6%) resulted in penetration. A slight increase in filter failure was observed in filter bacterial challenges with a differential pressure greater than 30 psid. When designing a commercial process for the sterile filtration of a low-surface-tension fluid (or any other potentially high-risk fluid), targeting the volume throughput range of 680-2260 mL/cm(2) or flux range of 7-18 mL/min/cm(2), and maintaining the differential pressure below 30 psid, could significantly decrease the risk of validation filter failure. However, it is important to keep in mind that these are general trends described in this study and some test fluids may not conform to the general trends described here. Ultimately, it is important to evaluate both filterability and bacterial retention of the test fluid under proposed process conditions prior to finalizing the manufacturing process to ensure successful process-specific filter validation of low-surface-tension fluids. An overwhelming majority of process-specific filter validation (qualification) tests result in the demonstration of absolute retention of test bacteria by sterilizing-grade membrane filters. As such, process-specific filter validation failure is rare. However, while bacterial penetration of sterilizing-grade filters during process-specific filter validation is rarely detected, some fluids (such as vaccines and liposomal fluids) have been associated with an increased incidence of bacterial penetration. The goal of the following analysis was to identify important drivers of process-specific filter validation failure. The identification of these drivers will possibly serve to assist in the design of commercial sterile filtration processes with a low risk of filter validation failure. Filter validation data for low-surface-tension fluids was collected and evaluated with regard to bacterial concentration and rates, as well as filtered fluid volume and rate (Pall Corporation). The master data set (∼1160 individual filtrations) included all recorded instances of process-specific filter validation failures but did not include all successful filter validation bacterial challenge tests. This allowed for a close examination of the conditions that lead to process-specific filter validation failure. As previously reported, two significant drivers of bacterial penetration were identified: the total bacterial load (the total number of bacteria per filter) and the bacterial load rate (the rate at which bacteria were applied to the filter). In addition to these parameters, another three possible drivers of failure were also identified: volumetric throughput, filter flux, and pressure. When designing a commercial process for the sterile filtration of a low-surface-tension fluid (or any other penetrative-risk fluid), targeting the identified bacterial challenge loads, volume throughput, and corresponding flux rates could decrease, and possibly eliminate, the risk of validation filter failure. However, it is important to keep in mind that these are general trends described in this study and some test fluids may not conform to the general trends described here. Ultimately, it is important to evaluate both filterability and bacterial retention of the test fluid under proposed process conditions prior to finalizing the manufacturing process to ensure successful filter validation of low-surface-tension fluids. © PDA, Inc. 2015.

Particle characterization in retail environments: concentrations, sources, and removal mechanisms.

PubMed

Zaatari, M; Siegel, J

2014-08-01

Particles in retail environments can have consequences for the occupational exposures of retail workers and customers, as well as the energy costs associated with ventilation and filtration. Little is known about particle characteristics in retail environments. We measured indoor and outdoor mass concentrations of PM10 and PM2.5 , number concentrations of submicron particles (0.02-1 μm), size-resolved 0.3-10 μm particles, as well as ventilation rates in 14 retail stores during 24 site visits in Pennsylvania and Texas. Overall, the results were generally suggestive of relatively clean environments when compared to investigations of other building types and ambient/occupational regulatory limits. PM10 and PM2.5 concentrations (mean ± s.d.) were 20 ± 14 and 11 ± 10 μg/m(3), respectively, with indoor-to-outdoor ratios of 1.0 ± 0.7 and 0.88 ± 1.0. Mean submicron particle concentrations were 7220 ± 7500 particles/cm(3) with an indoor-to-outdoor ratio of 1.18 ± 1.30. The median contribution to PM10 and PM2.5 concentrations from indoor sources (vs. outdoors) was 83% and 53%, respectively. There were no significant correlations between measured ventilation rates and particle concentrations of any size. When examining options to lower PM2.5 concentrations below regulatory limits, the required changes to ventilation and filtration efficiency were site specific and depended on the indoor and outdoor concentration, emission rate, and infiltration level. Little is known about particle concentrations, contribution of indoor sources, and emission rates in retail environments. Knowledge of these particle characteristics informs health scientists with input parameters to include in exposure modeling. The predicted concentration change in response to different ventilation rates and filtration efficiencies may be used for guidance to develop control strategies to lower particulate matter concentrations in retail environments. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Oregon Salt Marshes: How Blue are They?

EPA Science Inventory

Two important ecosystem services of wetlands are carbon sequestration and filtration of nutrients and particulates. We quantified the carbon and nitrogen accumulation rates in salt marshes at 135 plots distributed across eight estuaries located in Oregon, USA. Net carbon and ...

Monolith filter apparatus and membrane apparatus, and method using same

DOEpatents

Goldsmith, Robert L [Wayland, MA

2012-04-03

A filtration apparatus that separates a liquid feedstock mixed with a gas into filtrate and retentate, the apparatus including at least one filtration device comprised of at least one monolith segment of porous material that defines a plurality of passageways extending longitudinally from a feed face of the structure to a retentate end face. The filtration device contains at least one filtrate conduit within it for carrying filtrate toward a filtrate collection zone, the filtrate conduit providing a path of lower flow resistance than that of alternative flow paths through the porous material of the device. The filtration device can also be utilized as a membrane support for a device for microfiltration, ultrafiltration, nanofiltration, reverse osmosis, or pervaporation. Also disclosed is a method for using such a filtration apparatus.

Skin Autofluorescence and Subclinical Atherosclerosis in Mild to Moderate Chronic Kidney Disease: A Case-Control Study

PubMed Central

Sánchez, Enric; Betriu, Àngels; Arroyo, David; López, Carolina; Hernández, Marta; Rius, Ferran; Fernández, Elvira

2017-01-01

Advanced glycation end-products (AGEs) are increased and predict mortality in patients with chronic kidney disease (CKD) who are undergoing hemodialysis, irrespective of the presence of type 2 diabetes. However, little information exits about the relationship between AGEs and subclinical atherosclerosis at the early stages of CKD. A case-control study was performed including 87 patients with mild-to-moderate stages of CKD (glomerular filtration rate from 89 to 30 ml/min/per 1.73m2) and 87 non-diabetic non-CKD subjects matched by age, gender, body mass index, and waist circumference. Skin autofluorescence (AF), a non-invasive assessment of AGEs, was measured. The presence of atheromatous disease in carotid and femoral arteries was evaluated using vascular ultrasound, and vascular age and SCORE risk were estimated. Patients with mild-to-moderate stages of CKD showed an increase in skin AF compared with control subjects (2.5±0.6 vs. 2.2±0.4 AU, p<0.001). A skin AF value >2.0 AU was accompanied by a 3-fold increased risk of detecting the presence of an atheromathous plaque (OR 3.0, 95% CI 1.4–6.5, p = 0.006). When vascular age was assessed through skin AF, subjects with CKD were almost 12 years older than control subjects (70.3±25.5 vs. 58.5±20.2 years, p = 0.001). Skin AF was negatively correlated with glomerular filtration rate (r = -0.354, p<0.001) and LDL-cholesterol (r = -0.269, p = 0.001), and positively correlated with age (r = 0.472, p<0.001), pulse pressure (r = 0.238, p = 0.002), and SCORE risk (r = 0.451, p<0.001). A stepwise multivariate regression analysis showed that age and glomerular filtration rate independently predicted skin AF (R2 = 0.289, p<0.001). Skin AF is elevated in patients with mild-to-moderate CKD compared with control subjects. This finding may be independently associated with the glomerular filtration rate and the presence of subclinical atheromatous disease. Therefore, the use of skin AF may help to accurately evaluate the real cardiovascular risk at the early stages of CKD. PMID:28141808

The Development of a Microbial Challenge Test with Acholeplasma laidlawii To Rate Mycoplasma-Retentive Filters by Filter Manufacturers.

PubMed

Folmsbee, Martha; Lentine, Kerry Roche; Wright, Christine; Haake, Gerhard; Mcburnie, Leesa; Ashtekar, Dilip; Beck, Brian; Hutchison, Nick; Okhio-Seaman, Laura; Potts, Barbara; Pawar, Vinayak; Windsor, Helena

2014-01-01

Mycoplasma are bacteria that can penetrate 0.2 and 0.22 μm rated sterilizing-grade filters and even some 0.1 μm rated filters. Primary applications for mycoplasma filtration include large scale mammalian and bacterial cell culture media and serum filtration. The Parenteral Drug Association recognized the absence of standard industry test parameters for testing and classifying 0.1 μm rated filters for mycoplasma clearance and formed a task force to formulate consensus test parameters. The task force established some test parameters by common agreement, based upon general industry practices, without the need for additional testing. However, the culture medium and incubation conditions, for generating test mycoplasma cells, varied from filter company to filter company and was recognized as a serious gap by the task force. Standardization of the culture medium and incubation conditions required collaborative testing in both commercial filter company laboratories and in an Independent laboratory (Table I). The use of consensus test parameters will facilitate the ultimate cross-industry goal of standardization of 0.1 μm filter claims for mycoplasma clearance. However, it is still important to recognize filter performance will depend on the actual conditions of use. Therefore end users should consider, using a risk-based approach, whether process-specific evaluation of filter performance may be warranted for their application. Mycoplasma are small bacteria that have the ability to penetrate sterilizing-grade filters. Filtration of large-scale mammalian and bacterial cell culture media is an example of an industry process where effective filtration of mycoplasma is required. The Parenteral Drug Association recognized the absence of industry standard test parameters for evaluating mycoplasma clearance filters by filter manufacturers and formed a task force to formulate such a consensus among manufacturers. The use of standardized test parameters by filter manufacturers, including the preparation of the culture broth, will facilitate the end user's evaluation of the mycoplasma clearance claims provided by filter vendors. However, it is still important to recognize filter performance will depend on the actual conditions of use; therefore end users should consider, using a risk-based approach, whether process-specific evaluation of filter performance may be warranted for their application. © PDA, Inc. 2014.

Particle loading rates for HVAC filters, heat exchangers, and ducts.

PubMed

Waring, M S; Siegel, J A

2008-06-01

The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

Dust Effects on Nucleation Kinetics and Nanoparticle Product Size Distributions: Illustrative Case Study of a Prototype Ir(0)n Transition-Metal Nanoparticle Formation System.

PubMed

Özkar, Saim; Finke, Richard G

2017-07-05

The question is addressed if dust is kinetically important in the nucleation and growth of Ir(0) n nanoparticles formed from [Bu 4 N] 5 Na 3 (1,5-COD)Ir I ·P 2 W 15 Nb 3 O 62 (hereafter [(COD)Ir·POM] 8- ), reduced by H 2 in propylene carbonate solvent. Following a concise review of the (often-neglected) literature addressing dust in nucleation phenomena dating back to the late 1800s, the nucleation and growth kinetics of the [(COD)Ir·POM] 8- precatalyst system are examined for the effects of 0.2 μm microfiltration of the solvent and precatalyst solution, of rinsing the glassware with that microfiltered solvent, of silanizing the glass reaction vessel, for the addition of <0.2 μm γ-Al 2 O 3 (inorganic) dust, for the addition of flame-made carbon-based (organic) dust, and as a function of the starting, microfiltered [(COD)Ir·POM 8- ] concentration. Efforts to detect dust and its removal by dynamic light scattering and by optical microscopy are also reported. The results yield a list of eight important conclusions, the four most noteworthy of which are (i) that the nucleation apparent rate "constant" k 1obs(bimol) is shown to be slowed by a factor of ∼5 to ∼7.6, depending on the precise experiment and its conditions, just by the filtration of the precatalyst solution using a 0.20 μm filter and rinsing the glassware surface with 0.20 μm filtered propylene carbonate solvent; (ii) that simply employing a 0.20 μm filtration step narrows the size distribution of the resulting Ir(0) n nanoparticles by a factor of 2.4 from ±19 to ±8%, a remarkable result; (iii) that the narrower size distribution can be accounted for by the slowed nucleation rate constant, k 1obs(bimol) , and by the unchanged autocatalytic growth rate constant, k 2obs(bimol) , that is, by the increased ratio of k 2obs(bimol) /k 1obs(bimol) that further separates nucleation from growth in time for filtered vs unfiltered solutions; and (iv) that five lines of evidence indicate that the filterable component of the solution, which has nucleation rate-enhancing and size-dispersion broadening effects, is dust.

EFFECT OF VENTILATION SYSTEMS AND AIR FILTERS ON DECAY RATES OF PARTICLES PRODUCED BY INDOOR SOURCES IN AN OCCUPIED TOWNHOUSE

EPA Science Inventory

Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we me...

Optimized batch fermentation of cheese whey. Supplemented feedlot waste filtrate to produce a nitrogen-rich feed supplement for ruminants

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erdman, M.D.; Reddy, C.A.

1986-03-01

An optimized batch fermentation process for the conversion of cattle feedlot waste filtrate, supplemented with cheese whey, into a nitrogenous feed supplement for ruminants is described. Feedlot waste filtrate supplemented with cheese whey (5 g of whey per 100 ml) was fermented by the indigenous microbial flora in the feedlot waste filtrate. Ammonium hydroxide was added to the fermentation not only to maintain a constant pH but also to produce ammonium salts of organic acids, which have been shown to be valuable as nitrogenous feed supplements for ruminants. The utilization of substrate carbohydrate at pH 7.0 and 43 degrees Cmore » was greater than 94% within 8 h, and the crude protein (total N X 6.25) content of the product was 70 to 78% (dry weight basis). About 66 to 69% of the crude protein was in the form of ammonia nitrogen. Lactate and acetate were the predominant acids during the first 6 to 8 hours of fermentation, but after 24 hours, appreciable levels of propionate and butyrate were also present. The rate of fermentation and the crude protein content of the product were optimal at pH 7.0 and decreased at a lower pH. For example, fermentation did not go to completion even after 24 hours at pH 4.5. Fermentation proceeded optimally at 43 degrees C, less so at 37 degrees C, and considerably more slowly at 23 and 50 degrees C. Concentrations of up to 15 g of cheese whey per 100 ml of feedlot waste filtrate were fermented efficiently. Fermentation of feedlot waste filtrate obtained from animals fed low silage-high grain, high silage-low grain, or dairy rations resulted in similar products in terms of total nitrogen and organic acid composition.« less

Fire Detection Tradeoffs as a Function of Vehicle Parameters

NASA Technical Reports Server (NTRS)

Urban, David L.; Dietrich, Daniel L.; Brooker, John E.; Meyer, Marit E.; Ruff, Gary A.

2016-01-01

Fire survivability depends on the detection of and response to a fire before it has produced an unacceptable environment in the vehicle. This detection time is the result of interplay between the fire burning and growth rates; the vehicle size; the detection system design; the transport time to the detector (controlled by the level of mixing in the vehicle); and the rate at which the life support system filters the atmosphere, potentially removing the detected species or particles. Given the large differences in critical vehicle parameters (volume, mixing rate and filtration rate) the detection approach that works for a large vehicle (e.g. the ISS) may not be the best choice for a smaller crew capsule. This paper examines the impact of vehicle size and environmental control and life support system parameters on the detectability of fires in comparison to the hazard they present. A lumped element model was developed that considers smoke, heat, and toxic product release rates in comparison to mixing and filtration rates in the vehicle. Recent work has quantified the production rate of smoke and several hazardous species from overheated spacecraft polymers. These results are used as the input data set in the lumped element model in combination with the transport behavior of major toxic products released by overheating spacecraft materials to evaluate the necessary alarm thresholds to enable appropriate response to the fire hazard.

Estimated effect of ventilation and filtration on chronic health risks in U.S. offices, schools, and retail stores.

PubMed

Chan, W R; Parthasarathy, S; Fisk, W J; McKone, T E

2016-04-01

We assessed the chronic health risks from inhalation exposure to volatile organic compounds (VOCs) and particulate matter (PM2.5) in U.S. offices, schools, grocery, and other retail stores and evaluated how chronic health risks were affected by changes in ventilation rates and air filtration efficiency. Representative concentrations of VOCs and PM2.5 were obtained from available data. Using a mass balance model, changes in exposure to VOCs and PM2.5 were predicted if ventilation rate were to increase or decrease by a factor of two, and if higher efficiency air filters were used. Indoor concentrations were compared to health guidelines to estimate percentage exceedances. The estimated chronic health risks associated with VOC and PM2.5 exposures in these buildings were low relative to the risks from exposures in homes. Chronic health risks were driven primarily by exposures to PM2.5 that were evaluated using disease incidence of mortality, chronic bronchitis, and non-fatal stroke. The leading cancer risk factor was exposure to formaldehyde. Using disability-adjusted life years (DALYs) to account for both cancer and non-cancer effects, results suggest that increasing ventilation alone is ineffective at reducing chronic health burdens. Other strategies, such as pollutant source control and the use of particle filtration, should also be considered. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Building America Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts, Tyler, Texas

DOE Office of Scientific and Technical Information (OSTI.GOV)

?Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, andmore » filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy.« less

Long-Term Transport of Cryptosporidium Parvum

NASA Astrophysics Data System (ADS)

Andrea, C.; Harter, T.; Hou, L.; Atwill, E. R.; Packman, A.; Woodrow-Mumford, K.; Maldonado, S.

2005-12-01

The protozoan pathogen Cryptosporidium parvum is a leading cause of waterborne disease. Subsurface transport and filtration in natural and artificial porous media are important components of the environmental pathway of this pathogen. It has been shown that the oocysts of C. parvum show distinct colloidal properties. We conducted a series of laboratory studies on sand columns (column length: 10 cm - 60 cm, flow rates: 0.7 m/d - 30 m/d, ionic strength: 0.01 - 100 mM, filter grain size: 0.2 - 2 mm, various solution chemistry). Breakthrough curves were measured over relatively long time-periods (hundreds to thousands of pore volumes). We show that classic colloid filtration theory is a reasonable tool for predicting the initial breakthrough, but it is inadequate to explain the significant tailing observed in the breakthrough of C. parvum oocyst through sand columns. We discuss the application of the Continuous Time Random Walk approach to account for the strong tailing that was observed in our experiments. The CTRW is generalized transport modeling framework, which includes the classic advection-dispersion equation (ADE), the fractional ADE, and the multi-rate mass transfer model as special cases. Within this conceptual framework, it is possible to distinguish between the contributions of pore-scale geometrical (physical) disorder and of pore-scale physico-chemical heterogeneities (e.g., of the filtration, sorption, desorption processes) to the transport of C. parvum oocysts.

Extending the Dynamic Range of the Ion Trap by Differential Mobility Filtration

PubMed Central

Hall, Adam B.; Coy, Stephen L.; Kafle, Amol; Glick, James; Nazarov, Erkinjon

2013-01-01

A miniature, planar, differential ion mobility spectrometer (DMS) was interfaced to an LCQ classic ion trap to conduct selective ion filtration prior to mass analysis in order to extend the dynamic range of the trap. Space charge effects are known to limit the functional ion storage capacity of ion trap mass analyzers and this, in turn, can affect the quality of the mass spectral data generated. This problem is further exacerbated in the analysis of mixtures where the indiscriminate introduction of matrix ions results in premature trap saturation with non-targeted species, thereby reducing the number of parent ions that may be used to conduct MS/MS experiments for quantitation or other diagnostic studies. We show that conducting differential mobility-based separations prior to mass analysis allows the isolation of targeted analytes from electrosprayed mixtures preventing the indiscriminate introduction of matrix ions and premature trap saturation with analytically unrelated species. Coupling these two analytical techniques is shown to enhance the detection of a targeted drug metabolite from a biological matrix. In its capacity as a selective ion filter, the DMS can improve the analytical performance of analyzers such as quadrupole (3-D or linear) and ion cyclotron resonance (FT-ICR) ion traps that depend on ion accumulation. PMID:23797861

Evaluation of the oleophilicity of different alkoxysilane modified ceramic membranes through wetting dynamic measurements

NASA Astrophysics Data System (ADS)

Gao, Nengwen; Ke, Wei; Fan, Yiqun; Xu, Nanping

2013-10-01

Wettability has been recognized as one of the most important properties of porous materials for both fundamental and practical applications. In this study, the oleophilicity of Al2O3 membranes modified by four alkoxysilanes with different length of alkyl group was investigated through oil wetting dynamic test. Fourier transform infrared spectroscopy (FTIR), thermogravimertric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were measured to confirm that ceramic membrane surfaces have been grafted with alkoxysilanes without changing the membrane morphology. A high speed video camera was used to record the spreading and imbibition process of oil on the modified membrane surface. The value of oil contact angle and its change during the wetting process were used to characterize the membrane oleophilicity. Characterization results showed that the oleophilicity of the modified membranes increased along with the increasing of the silane alkyl group. The influence of oleophilicity on the filtration performance of water-in-oil (W/O) emulsions was experimentally studied. A higher oil flux was obtained for membranes grafted with a longer alkyl group, indicating that increase oleophilicity can increase the membrane antifouling property. This work presents a valuable route to the surface oleophilicity control and testing of ceramic membranes in the filtration of non-polar organic solvents.

Efficacy of nebivolol-valsartan single-pill combination in obese and nonobese patients with hypertension.

PubMed

Mende, Christian W; Giles, Thomas D; Bharucha, David B; Ferguson, William G; Mallick, Madhuja; Patel, Mehul D

2017-06-01

Antihypertensive efficacy of single-pill combinations (SPCs) consisting of a β 1 -selective adrenergic blocker with vasodilatory properties via β 3 -agonism (nebivolol) and an angiotensin II receptor blocker (valsartan) was demonstrated in an 8-week phase 3 trial (NCT01508026). In this post hoc analysis, seated blood pressure, heart rate, 24-hour ambulatory blood pressure monitoring, plasma aldosterone, estimated glomerular filtration rate, and safety measures were assessed in obese (body mass index >32 kg/m 2 ; n=1823) and nonobese (body mass index <27 kg/m 2 ; n=847) adults with hypertension (stage I or II) treated with nebivolol-valsartan SPCs, nebivolol or valsartan monotherapy, or placebo. At week 8, reductions from baseline in blood pressure and ambulatory blood pressure monitoring were greater with SPCs and most nebivolol and valsartan monotherapy doses vs placebo regardless of obesity status. Aldosterone declined with all active treatments and estimated glomerular filtration rate remained steady. The nebivolol-valsartan 5/80 mg/d SPC was efficacious regardless of degree of obesity. © 2017 The Authors. The Journal of Clinical Hypertension Published by Wiley Periodicals, Inc.

Inertial Particle Migration in the Presence of a Permeate Flow

NASA Astrophysics Data System (ADS)

Garcia, Mike; Singelton, Amanda; Pennathur, Sumita

2016-11-01

Tangential Flow Filtration (TFF) is a rapid and efficient method for the filtration and separation of suspensions of particles such as viruses, bacteria or cellular material. Enhancing the efficacy of TFF not only requires a detailed understanding of particle transport mechanisms, but also the interactions between these mechanisms and a porous wall. In this work, we numerically and experimentally explore the mechanisms of inertial particle migration in the presence of a permeate flow through the porous walls of a microchannel. Numerically, we develop a force balance model to understand the competition between permeate and inertial forces and the resultant consequences on the particle equilibrium location. Experimentally, we fabricated MEMS TFF devices to study the migration of 5, 10 and 15 µm fluorescent polystyrene beads in straight channels with perpendicular permeate flow rates up to 90% of the inlet flow rate. We find that the permeate flow directly influences the inertial focusing position of the particles, both as a function of downstream channel position and ratio of inlet to outlet flow rate. Comparing experiments to our model, we can identify inertial, viscous and a co-dominant regimes.

Bioconcentration of the antidepressant fluoxetine and its effects on the physiological and biochemical status in Daphnia magna.

PubMed

Ding, Jiannan; Zou, Hua; Liu, Qingqing; Zhang, Shanshan; Mamitiana Razanajatovo, Roger

2017-08-01

The aim of this study was to evaluate the bioconcentration potential of fluoxetine and its biological effects in Daphnia magna. After 48h of waterborne exposure, the bioconcentration of fluoxetine in D. magna was determined to be 460.61 and 174.41Lkg -1 for nominal exposure concentrations of 0.5 and 5µgL -1 , respectively. Moreover, various biological endpoints, including physiological responses (filtration and ingestion rates), enzymatic biomarkers related to neurotoxicity [acetylcholinesterase (AChE)] and antioxidant defense [superoxide dismutase (SOD)], and an oxidative stress damage marker [malondialdehyde (MDA)], were assessed. Fluoxetine exposure increased the filtration rate of daphnia, while the ingestion rate was not obviously modified. AChE activity was significantly inhibited, highlighting the neurotoxicity of fluoxetine on D. magna. However, with some alterations in the SOD activity and MDA content, no obvious oxidative damage was observed in D. magna exposed to fluoxetine at the tested concentrations. These results indicate that fluoxetine can be accumulated and consequently induce physiological and biochemical perturbations in D. magna. Copyright © 2017. Published by Elsevier Inc.

[Evaluation of three methods for forensic diatom test].

PubMed

Wang, Yuzhong; Zhao, Jian; Li, Peng; Hu, Sunlin; Wang, Huipin; Wang, Huijun; Liu, Chao

2015-03-01

To compare the efficacy of three methods for forensic diatom test, namely strong acid digestion-centrifuge enrichment-light microscopy (SD-CE-LM), microwave digestion-membrane filtration-automated scanning electron microscopy (MD-ME-SEM), and microwave digestion-membrane filtration-light microscopy (MD-MF-LM). Sixty samples were randomly divided into 3 groups for diatom test using three methods, and the sample preparation time, degree of digestion and recovery rate of diatoms were compared. The sample preparation time was the shortest with MD-MF-LM and the longest with SD-CE-LM (P<0.05). MD-ME-SEM and MD-MF-LM allowed more thorough tissue digestion than SD-CE-LM. MD-ME-SEM resulted in the highest total recovery rate of diatom, followed by MD-MF-LM and then by SD-CE-LM (P<0.05); the recover rate of different diatom species was the highest with MD-ME-SEM, followed by MD-MF-LM and SD-CE-LM (P<0.05). SD-CE-LM has a low recovery rate of diatoms especially for those with lengths shorter than 40 µm or densities less than 1/5. With a high recovery rate and accuracy in diatom test, MD-ME-SEM is suitable for diagnosis of suspected drowning cases. MD-MF-LM is highly efficient, sensitive and convenient for forensic diatom test.

28 CFR 79.67 - Proof of chronic renal disease.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Abnormal glomerular filtration rate (by either measured creatinine or iothalamate clearance or calculated... report; (5) Hospital discharge summary report; (6) Hospital admitting report; or (7) Death certificate, provided that it is signed by a physician at the time of death. ...

28 CFR 79.57 - Proof of chronic renal disease.

Code of Federal Regulations, 2014 CFR

2014-07-01

... filtration rate (by either measured creatinine or iothalamate clearance or calculated by MDRD equation); and... discharge summary report; (6) Hospital admitting report; or (7) Death certificate, provided that it is signed by a physician at the time of death. ...

28 CFR 79.67 - Proof of chronic renal disease.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Abnormal glomerular filtration rate (by either measured creatinine or iothalamate clearance or calculated... report; (5) Hospital discharge summary report; (6) Hospital admitting report; or (7) Death certificate, provided that it is signed by a physician at the time of death. ...

28 CFR 79.57 - Proof of chronic renal disease.

Code of Federal Regulations, 2012 CFR

2012-07-01

... filtration rate (by either measured creatinine or iothalamate clearance or calculated by MDRD equation); and... discharge summary report; (6) Hospital admitting report; or (7) Death certificate, provided that it is signed by a physician at the time of death. ...

28 CFR 79.57 - Proof of chronic renal disease.

Code of Federal Regulations, 2013 CFR

2013-07-01

... filtration rate (by either measured creatinine or iothalamate clearance or calculated by MDRD equation); and... discharge summary report; (6) Hospital admitting report; or (7) Death certificate, provided that it is signed by a physician at the time of death. ...

28 CFR 79.67 - Proof of chronic renal disease.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Abnormal glomerular filtration rate (by either measured creatinine or iothalamate clearance or calculated... report; (5) Hospital discharge summary report; (6) Hospital admitting report; or (7) Death certificate, provided that it is signed by a physician at the time of death. ...

Conformational changes in human Hsp70 induced by high hydrostatic pressure produce oligomers with ATPase activity but without chaperone activity.

PubMed

Araujo, Thaís L S; Borges, Julio Cesar; Ramos, Carlos H; Meyer-Fernandes, José Roberto; Oliveira Júnior, Reinaldo S; Pascutti, Pedro G; Foguel, Debora; Palhano, Fernando L

2014-05-13

We investigated the folding of the 70 kDa human cytosolic inducible protein (Hsp70) in vitro using high hydrostatic pressure as a denaturing agent. We followed the structural changes in Hsp70 induced by high hydrostatic pressure using tryptophan fluorescence, molecular dynamics, circular dichroism, high-performance liquid chromatography gel filtration, dynamic light scattering, ATPase activity, and chaperone activity. Although monomeric, Hsp70 is very sensitive to hydrostatic pressure; after pressure had been removed, the protein did not return to its native sate but instead formed oligomeric species that lost chaperone activity but retained ATPase activity.

Suspended particle transport through constriction channel with Brownian motion

NASA Astrophysics Data System (ADS)

Hanasaki, Itsuo; Walther, Jens H.

2017-08-01

It is well known that translocation events of a polymer or rod through pores or narrower parts of micro- and nanochannels have a stochastic nature due to the Brownian motion. However, it is not clear whether the objects of interest need to have a larger size than the entrance to exhibit the deviation from the dynamics of the surrounding fluid. We show by numerical analysis that the particle injection into the narrower part of the channel is affected by thermal fluctuation, where the particles have spherical symmetry and are smaller than the height of the constriction. The Péclet number (Pe) is the order parameter that governs the phenomena, which clarifies the spatio-temporal significance of Brownian motion compared to hydrodynamics. Furthermore, we find that there exists an optimal condition of Pe to attain the highest flow rate of particles relative to the dispersant fluid flow. Our finding is important in science and technology from nanopore DNA sequencers and lab-on-a-chip devices to filtration by porous materials and chromatography.

Current concepts of space flight induced changes in hormonal control of fluid and electrolyte metabolism

NASA Technical Reports Server (NTRS)

Leach, C. S.; Johnson, P. C.; Suki, W. N.

1983-01-01

A systematic analysis of body fluid and renal dynamics during simulated space flight (head-down bedrest) was undertaken to increase understanding of the physiologic effects of acute cephalad fluid shifts. The earliest effects were increases in central venous pressure and decreases in plasma aldosterone, epinephrine and norepinephrine and glomerular filtration rate, 2 h after the beginning of bedrest. Decreases in plasma angiotensin I at 6 h may have resulted from the increased effective pressure and decreased sympathetic activity seen earlier in bedrest. The early decrease in aldosterone and ADH is thought to contribute to an increase, by 6 h, in urinary excretion of salt and water. Fluid and electrolyte losses occur during space flight, and analysis of body fluids from Space Shuttle crewmembers has indicated that conservation of these substances is begun almost immediately upon cessation of weightlessness. Operational medicine measures to counteract dehydration and electrolyte loss resulted in a less extreme physiologic response to the flight.

Suspended particle transport through constriction channel with Brownian motion.

PubMed

Hanasaki, Itsuo; Walther, Jens H

2017-08-01

It is well known that translocation events of a polymer or rod through pores or narrower parts of micro- and nanochannels have a stochastic nature due to the Brownian motion. However, it is not clear whether the objects of interest need to have a larger size than the entrance to exhibit the deviation from the dynamics of the surrounding fluid. We show by numerical analysis that the particle injection into the narrower part of the channel is affected by thermal fluctuation, where the particles have spherical symmetry and are smaller than the height of the constriction. The Péclet number (Pe) is the order parameter that governs the phenomena, which clarifies the spatio-temporal significance of Brownian motion compared to hydrodynamics. Furthermore, we find that there exists an optimal condition of Pe to attain the highest flow rate of particles relative to the dispersant fluid flow. Our finding is important in science and technology from nanopore DNA sequencers and lab-on-a-chip devices to filtration by porous materials and chromatography.

Reactive solute transport in an acidic stream: Experimental pH increase and simulation of controls on pH, aluminum, and iron

USGS Publications Warehouse

Broshears, R.E.; Runkel, R.L.; Kimball, B.A.; McKnight, Diane M.; Bencala, K.E.

1996-01-01

Solute transport simulations quantitatively constrained hydrologic and geochemical hypotheses about field observations of a pH modification in an acid mine drainage stream. Carbonate chemistry, the formation of solid phases, and buffering interactions with the stream bed were important factors in explaining the behavior of pH, aluminum, and iron. The precipitation of microcrystalline gibbsite accounted for the behavior of aluminum; precipitation of Fe(OH)3 explained the general pattern of iron solubility. The dynamic experiment revealed limitations on assumptions that reactions were controlled only by equilibrium chemistry. Temporal variation in relative rates of photoreduction and oxidation influenced iron behavior. Kinetic limitations on ferrous iron oxidation and hydrous oxide precipitation and the effects of these limitations on field filtration were evident. Kinetic restraints also characterized interaction between the water column and the stream bed, including sorption and desorption of protons from iron oxides at the sediment-water interface and post-injection dissolution of the precipitated aluminum solid phase.

The Dynamics of Glomerular Ultrafiltration in the Rat

PubMed Central

Brenner, Barry M.; Troy, Julia L.; Daugharty, Terrance M.

1971-01-01

Using a unique strain of Wistar rats endowed with glomeruli situated directly on the renal cortical surface, we measured glomerular capillary pressures using servo-nulling micropipette transducer techniques. Pressures in 12 glomerular capillaries from 7 rats averaged 60 cm H2O, or approximately 50% of mean systemic arterial values. Wave form characteristics for these glomerular capillaries were found to be remarkably similar to those of the central aorta. From similarly direct estimates of hydrostatic pressures in proximal tubules, and colloid osmotic pressures in systemic and efferent arteriolar plasmas, the net driving force for ultrafiltration was calculated. The average value of 14 cm H2O is lower by some two-thirds than the majority of estimates reported previously based on indirect techniques. Single nephron GFR (glomerular filtration rate) was also measured in these rats, thereby permitting calculation of the glomerular capillary ultrafiltration coefficient. The average value of 0.044 nl sec−1 cm H2O−1 glomerulus−1 is at least fourfold greater than previous estimates derived from indirect observations. PMID:5097578

Magnetically Enhanced Solid-Liquid Separation

NASA Astrophysics Data System (ADS)

Rey, C. M.; Keller, K.; Fuchs, B.

2005-07-01

DuPont is developing an entirely new method of solid-liquid filtration involving the use of magnetic fields and magnetic field gradients. The new hybrid process, entitled Magnetically Enhanced Solid-Liquid Separation (MESLS), is designed to improve the de-watering kinetics and reduce the residual moisture content of solid particulates mechanically separated from liquid slurries. Gravitation, pressure, temperature, centrifugation, and fluid dynamics have dictated traditional solid-liquid separation for the past 50 years. The introduction of an external field (i.e. the magnetic field) offers the promise to manipulate particle behavior in an entirely new manner, which leads to increased process efficiency. Traditional solid-liquid separation typically consists of two primary steps. The first is a mechanical step in which the solid particulate is separated from the liquid using e.g. gas pressure through a filter membrane, centrifugation, etc. The second step is a thermal drying process, which is required due to imperfect mechanical separation. The thermal drying process is over 100-200 times less energy efficient than the mechanical step. Since enormous volumes of materials are processed each year, more efficient mechanical solid-liquid separations can be leveraged into dramatic reductions in overall energy consumption by reducing downstream drying requirements have a tremendous impact on energy consumption. Using DuPont's MESLS process, initial test results showed four very important effects of the magnetic field on the solid-liquid filtration process: 1) reduction of the time to reach gas breakthrough, 2) less loss of solid into the filtrate, 3) reduction of the (solids) residual moisture content, and 4) acceleration of the de-watering kinetics. These test results and their potential impact on future commercial solid-liquid filtration is discussed. New applications can be found in mining, chemical and bioprocesses.

Molecular dynamics simulations reveal that water diffusion between graphene oxide layers is slow

DOE PAGES

Devanathan, Ram; Chase-Woods, Dylan; Shin, Yongsoon; ...

2016-07-08

Membranes made of stacked layers of graphene oxide (GO) hold the tantalizing promise of revolutionizing desalination and water filtration if selective transport of molecules can be controlled. We present the findings of a molecular dynamics simulation study of water intercalated between GO layers that have a C/O ratio of 4. We simulated a range of hydration levels from 1 wt.% to 23.3 wt.% water. The interlayer spacing increased upon hydration from 0.8 nm to 1.1 nm. We also synthesized GO membranes that showed an increase in spacing from about 0.7 nm to 0.8 nm and an increase in mass ofmore » about 14% on hydration. Water diffusion through GO layers is an order of magnitude slower than that in bulk water, because of strong hydrogen bonded interactions. Most of the water molecules are bound to OH groups even at the highest hydration level. We observed large water clusters that could span graphitic regions, oxidized regions and holes that have been experimentally observed in GO. As a result, slow interlayer diffusion can be consistent with experimentally observed water transport in GO if holes lead to a shorter path length than previously assumed and sorption serves as a key rate-limiting step.« less

8. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

8. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT (#1773), LOOKING SOUTHWEST, SHOWING MEZZANINE WITH FILTER TANKS AT REAR - Presidio Water Treatment Plant, Filtration Plant, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

7. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. OBLIQUE INTERIOR VIEW OF FILTRATION ROOM IN FILTRATION PLANT (#1773), LOOKING NORTHEAST, SHOWING PUMP NO. 1 AND METERING EQUIPMENT - Presidio Water Treatment Plant, Filtration Plant, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

Dynamics of L-Carnitine in Plasma and Urine in Patients Undergoing Cisplatin Chemotherapy.

PubMed

Gomi, Daisuke; Tanaka, Aika; Fukushima, Toshirou; Kobayashi, Takashi; Matsushita, Hirohide; Sekiguchi, Nodoka; Sakamoto, Akiyuki; Sasaki, Shigeru; Mamiya, Keiko; Koizumi, Tomonobu

2017-01-01

Several studies have indicated that cisplatin (cis-diamminedichloroplatinum II; CDDP) causes urinary excretion of L-carnitine (LC). However, the underlying cofactors affecting the increased urinary excretion remain unclear. The present study was performed to evaluate the dynamics of LC in plasma and urine after CDDP chemotherapy and to examine the relations with clinical parameters, such as gender, body mass index (BMI), and renal function. Twenty-two patients treated with CDDP therapy were selected. Blood and urine samples were taken from patients before starting CDDP treatment (day 0), on the next day (day 1), and on the seventh day (day 7). We measured plasma and urine concentrations of total, free, and acyl-LC, and examined the relationships with gender, age, treatment cycle, skeletal muscle mass, BMI, glomerular filtration rate, and change in creatinine concentration after CDDP administration. Both urinary and plasma concentrations of 3 types of LC increased markedly on day 1 and subsequently reverted to the pre-CDDP level on day 7. There was a positive correlation between the % changes in plasma and urine LC (correlation coefficient 0.59, p = 0.003) on day 1, but no significant relations were seen in other clinical parameters. CDDP transiently increased plasma LC levels. The mechanism seemed to involve recruitment for marked urinary loss of LC. However, these changes in plasma and urinary LC levels were not related to clinical factors, suggesting that the dynamics of LC were independent of preexisting physical parameters. © 2017 S. Karger AG, Basel.

Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin

PubMed Central

Zhao, Dan; Azimi, Parham; Stephens, Brent

2015-01-01

Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002–2.5% and increase life expectancy by 0.02–1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location. PMID:26197328

Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin.

PubMed

Zhao, Dan; Azimi, Parham; Stephens, Brent

2015-07-21

Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002-2.5% and increase life expectancy by 0.02-1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location.

Modeling of Oil Output Intensification in Porous Permeable Medium at Acoustical Stimulation from a Well

NASA Astrophysics Data System (ADS)

Maksimov, German A.; Radchenko, Aleksei V.

2006-05-01

Acoustical stimulation (AS) of oil production rate from a well is perspective technology for oil industry but physical mechanisms of acoustical action are not understood clear due to complex character of the phenomena. In practice the role of these mechanisms is appeared non-directly in the form of additional oil output. Thus the validity examination of any physical model has to be carried out as with account of mechanism of acoustic action by itself as well with account of previous and consequent stages dealt with fluid filtration into a well. The advanced model of physical processes taking place at acoustical stimulation is considered in the framework of heating mechanism of acoustical action, but for two-component fluid in porous permeable media. The porous fluid is considered as consisted of light and heavy hydrocarbonaceous phases, which are in a thermodynamic equilibrium. Filtration or acoustical stimulation can change equilibrium balance between phases so the heavy phase can be precipitated on pores walls or dissolved. The set of acoustical, heat and filtration tasks were solved numerically to describe oil output from a well — the final result of acoustical action, which can be compared with experimental data. It is shown that the suggested numerical model allows us to reproduce the basic features of fluid filtration in a well before during and after acoustical stimulation.

Association of the cystatin C/creatinine ratio with the renally cleared hormones parathyroid hormone (PTH) and brain natriuretic peptide (BNP) in primary care patients: a cross-sectional study.

PubMed

Risch, Martin; Risch, Lorenz; Purde, Mette-Triin; Renz, Harald; Ambühl, Patrice; Szucs, Thomas; Tomonaga, Yuki

2016-09-01

The ratio of cystatin C to creatinine (cysC/crea) is regarded as a marker of glomerular filtration quality and predicts mortality. It has been hypothesized that increased mortality may be mediated by the retention of biologically active substances due to shrinking glomerular pores. The present study investigated whether cysC/crea is independently associated with the levels of two renally cleared hormones, which have been linked to increased mortality. We conducted a multicenter, cross-sectional study with a random selection of general practitioners (GPs) from all GP offices in seven Swiss cantons. Markers of glomerular filtration quality were investigated together with estimated glomerular filtration rate (eGFR), albuminuria and urinary neutrophil gelatinase associated lipocalin (uNGAL) as well as two renally cleared low-molecular-weight protein hormones (i.e. BNP and PTH), Morbidity was assessed with the Charlson Comorbidity Index (CCI). A total of 1000 patients (433 males; mean age 57 ± 17 years) were included. There was a significant univariate association of BNP (r = 0.36, p < 0.001) and PTH (r = 0.18, p < 0.001) with cysC/crea. An adjusted model that accounted for kidney function (eGFR), altered glomerular structure (albuminuria), renal stress (uNGAL), and CCI showed that BNP and PTH were independently associated with cysC/crea as well as with the ratio of cystatin C-based to creatinine-based eGFR. In conclusion, in primary care patients, BNP and PTH are independently associated both with markers of glomerular filtration quality and eGFR regardless of structural kidney damage or renal stress. These findings offer an explanation, how altered glomerular filtration quality could contribute to increased mortality.

Impact of backwashing procedures on deep bed filtration productivity in drinking water treatment.

PubMed

Slavik, Irene; Jehmlich, Alexander; Uhl, Wolfgang

2013-10-15

Backwash procedures for deep bed filters were evaluated and compared by means of a new integrated approach based on productivity. For this, different backwash procedures were experimentally evaluated by using a pilot plant for direct filtration. A standard backwash mode as applied in practice served as a reference and effluent turbidity was used as the criterion for filter run termination. The backwash water volumes needed, duration of the filter-to-waste period, time out of operation, total volume discharged and filter run-time were determined and used to calculate average filtration velocity and average productivity. Results for filter run-times, filter backwash volumes, and filter-to-waste volumes showed considerable differences between the backwash procedures. Thus, backwash procedures with additional clear flushing phases were characterised by an increased need for backwash water. However, this additional water consumption could not be compensated by savings during filter ripening. Compared to the reference backwash procedure, filter run-times were longer for both single-media and dual-media filters when air scour and air/water flush were optimised with respect to flow rates and the proportion of air and water. This means that drinking water production time is longer and less water is needed for filter bed cleaning. Also, backwashing with additional clear flushing phases resulted in longer filter run-times before turbidity breakthrough. However, regarding the productivity of the filtration process, it was shown that it was almost the same for all of the backwash procedures investigated in this study. Due to this unexpected finding, the relationships between filter bed cleaning, filter ripening and filtration performance were considered and important conclusions and new approaches for process optimisation and resource savings were derived. Copyright © 2013 Elsevier Ltd. All rights reserved.

Extracellular biosynthesis of silver nanoparticles using a novel and non-pathogenic fungus, Neurospora intermedia: controlled synthesis and antibacterial activity.

PubMed

Hamedi, Sepideh; Shojaosadati, Seyed Abbas; Shokrollahzadeh, Soheila; Hashemi-Najafabadi, Sameereh

2014-02-01

In the present study, the biosynthesis of silver nanoparticles (AgNPs) using Neurospora intermedia, as a new non-pathogenic fungus was investigated. For determination of biomass harvesting time, the effect of fungal incubation period on nanoparticle formation was investigated using UV-visible spectroscopy. Then, AgNPs were synthesized using both culture supernatant and cell-free filtrate of the fungus. Two different volume ratios (1:100 and 1:1) of the culture supernatant to the silver nitrate were employed for AgNP synthesis. In addition, cell-free filtrate and silver nitrate were mixed in presence and absence of light. Smallest average size and highest productivity were obtained when using equal volumes of the culture supernatant and silver nitrate solution as confirmed by UV-visible spectra of colloidal AgNPs. Comparing the UV-visible spectra revealed that using cell-free filtrate for AgNP synthesis resulted in the formation of particles with higher stability and monodispersity than using culture supernatant. The absence of light in cell-free filtrate mediated synthesis led to the formation of nanoparticles with the lowest rate and the highest monodispersity. The presence of elemental silver in all prepared samples was confirmed using EDX, while the crystalline nature of synthesized particles was verified by XRD. FTIR results showed the presence of functional groups which reduce Ag(+) and stabilize AgNPs. The presence of nitrate reductase was confirmed in the cell-free filtrate of the fungus suggesting the potential role of this enzyme in AgNP synthesis. Synthesized particles showed significant antibacterial activity against E. coli as confirmed by examining the growth curve of bacterial cells exposed to AgNPs.

Preliminary evaluation of fungicidal and termiticidal activities of filtrates from biomass slurry fuel production.

PubMed

Kartal, S N; Imamura, Y; Tsuchiya, F; Ohsato, K

2004-10-01

Biomass slurry fuel (BSF) production has recently been developed as a natural energy for the conversion of solid biomass into fuel. In addition to using fuel, filtrates from BSF production may also serve a chemical source with several organic compounds. There is an increasing interest in the research and application of biomass-based filtrates. In this study, fungicidal and termiticidal properties of filtrates from BSF production using sugi (Cryptomeria japonica) and acacia (Acacia mangium) wood were evaluated in laboratory decay and termite resistance tests. Wood blocks treated with the filtrates showed increased resistance against brown-rot fungus, Fomitopsis palustris. However the filtrates from sugi wood processed at 270 degrees C which contained less phenolic compounds than the other filtrates were effective against white-rot fungus, Trametes versicolor. Phenolic compounds of filtrates seemed to play a role in the decay resistance tests however the filtrates did not increase the durability of the wood blocks against subterranean termites Coptotermes formosanus. Despite high acetic and lactic acid content of the filtrates, vanillin content of the filtrates may have served as an additional food source and promoted termite attack. It can be concluded that filtrates with phenolic compounds from lignin degradation during BSF production can be considered for targeted inhibition of brown-rot.

Challenge of N95 Filtering Facepiece Respirators with Viable H1N1 Influenza Aerosols

PubMed Central

Harnish, Delbert A.; Heimbuch, Brian K.; Husband, Michael; Lumley, April E.; Kinney, Kimberly; Shaffer, Ronald E.; Wander, Joseph D.

2015-01-01

OBJECTIVE Specification of appropriate personal protective equipment for respiratory protection against influenza is somewhat controversial. In a clinical environment, N95 filtering facepiece respirators (FFRs) are often recommended for respiratory protection against infectious aerosols. This study evaluates the ability of N95 FFRs to capture viable H1N1 influenza aerosols. METHODS Five N95 FFR models were challenged with aerosolized viable H1N1 influenza and inert polystyrene latex particles at continuous flow rates of 85 and 170 liters per minute. Virus was assayed using Madin-Darby canine kidney cells to determine the median tissue culture infective dose (TCID50). Aerosols were generated using a Collison nebulizer containing H1N1 influenza virus at 1 × 108 TCID50/mL. To determine filtration efficiency, viable sampling was performed upstream and downstream of the FFR. RESULTS N95 FFRs filtered 0.8-µm particles of both H1N1 influenza and inert origins with more than 95% efficiency. With the exception of 1 model, no statistically significant difference in filtration performance was observed between influenza and inert particles of similar size. Although statistically significant differences were observed for 2 models when comparing the 2 flow rates, the differences have no significance to protection. CONCLUSIONS This study empirically demonstrates that a National Institute for Occupational Safety and Health–approved N95 FFR captures viable H1N1 influenza aerosols as well as or better than its N95 rating, suggesting that a properly fitted FFR reduces inhalation exposure to airborne influenza virus. This study also provides evidence that filtration efficiency is based primarily on particle size rather than the nature of the particle’s origin. PMID:23571366

Differential associations between glomerular filtration rate and duration of obesity depending on the presence or absence of left ventricular diastolic dysfunction.

PubMed

Ybarra, Juan; Sánchez-Hernández, Joan; Vilallonga, Ramon; Romeo, June H

2016-07-01

A robust and consistent association between increasing body mass index (BMI) and chronic kidney disease (CKD) has been reported in several observational studies. Obesity remains the main preventable risk factor for CKD because it largely mediates diabetes and hypertension, the 2 most common etiologies for end-stage kidney disease (ESKD). Obesity is associated weakly with early stages of kidney disease but strongly with kidney progression to ESKD, even after adjustment for hypertension and diabetes. To assess the relationship between estimated glomerular filtration rate (eGFR) and trans-thoracic echocardiography left ventricular function parameters in a cohort of patients with obesity. Cross-sectional study involving 324 obese (BMI=44.0±2.2Kg/m(2)) apparently healthy asymptomatic patients with an eGFR >60ml/min/1.73m(2). Each patient underwent transthoracic echocardiography and a blood testing. The eGFR was addressed by the CKD-EPI formula. All patients had a normal systolic function whereas 24.5% disclosed diastolic dysfunction (DD). Hypertension and type 2 diabetes mellitus prevalence were 34.5% and 4.5% (respectively). All patients disclosed an eGFR >60ml/min while none of them disclosed hyperfiltration (eGFR >120ml/min). eGFR correlated inversely with BMI and the duration of obesity and positively with diastolic function parameters (P<0.001 for all, respectively). Patients with diastolic dysfunction displayed lower eGFR (P<0.0005) and longer duration of obesity (P<0.0005). Obesity and its duration are likely to impose hemodynamic changes affecting simultaneously both heart (diastolic dysfunction) and kidney (decreased glomerular filtration rate). Larger prospective studies are warranted. Copyright © 2016 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

Comparison between a serum creatinine-and a cystatin C-based glomerular filtration rate equation in patients receiving amphotericin B.

PubMed

Karimzadeh, Iman; Khalili, Hossein

2016-06-06

Serum cystatin C (Cys C) has a number of advantages over serum creatinine in the evaluation of kidney function. Apart from Cys C level itself, several formulas have also been introduced in different clinical settings for the estimation of glomerular filtration rate (GFR) based upon serum Cys C level. The aim of the present study was to compare a serum Cys C-based equation with Cockcroft-Gault serum creatinine-based formula, both used in the calculation of GFR, in patients receiving amphotericin B. Fifty four adult patients with no history of acute or chronic kidney injury having been planned to receive conventional amphotericin B for an anticipated duration of at least 1 week for any indication were recruited. At three time points during amphotericin B treatment, including days 0, 7, and 14, serum cystatin C as well as creatinine levels were measured. GFR at the above time points was estimated by both creatinine (Cockcroft-Gault) and serum Cys C based equations. There was significant correlation between creatinine-based and Cys C-based GFR values at days 0 (R = 0.606, P = 0.001) and 7 (R = 0.714, P < 0.001). In contrast to GFR estimated by the Cockcroft-Gault equation, the mean (95 % confidence interval) Cys C-based GFR values at different studied time points were comparable within as well as between patients with and without amphotericin B nephrotoxicity. Our results suggested that the Gentian Cys C-based GFR equation correlated significantly with the Cockcroft-Gault formula at least at the early time period of treatment with amphotericin B. Graphical abstract Comparison between a serum creatinine-and a cystatin C-based glomerular filtration rate equation in patients receiving amphotericin B.

Sample dilution and bacterial community composition influence empirical leucine-to-carbon conversion factors in surface waters of the world's oceans.

PubMed

Teira, Eva; Hernando-Morales, Víctor; Cornejo-Castillo, Francisco M; Alonso-Sáez, Laura; Sarmento, Hugo; Valencia-Vila, Joaquín; Serrano Catalá, Teresa; Hernández-Ruiz, Marta; Varela, Marta M; Ferrera, Isabel; Gutiérrez Morán, Xosé Anxelu; Gasol, Josep M

2015-12-01

The transformation of leucine incorporation rates to prokaryotic carbon production rates requires the use of either theoretical or empirically determined conversion factors. Empirical leucine-to-carbon conversion factors (eCFs) vary widely across environments, and little is known about their potential controlling factors. We conducted 10 surface seawater manipulation experiments across the world's oceans, where the growth of the natural prokaryotic assemblages was promoted by filtration (i.e., removal of grazers [F treatment]) or filtration combined with dilution (i.e., also relieving resource competition [FD treatment]). The impact of sunlight exposure was also evaluated in the FD treatments, and we did not find a significant effect on the eCFs. The eCFs varied from 0.09 to 1.47 kg C mol Leu(-1) and were significantly lower in the FD than in the F samples. Also, changes in bacterial community composition during the incubations, as assessed by automated ribosomal intergenic spacer analysis (ARISA), were more pronounced in the FD than in the F treatments, compared to unmanipulated controls. Thus, we discourage the common procedure of diluting samples (in addition to filtration) for eCF determination. The eCFs in the filtered treatment were negatively correlated with the initial chlorophyll a concentration, picocyanobacterial abundance (mostly Prochlorococcus), and the percentage of heterotrophic prokaryotes with high nucleic acid content (%HNA). The latter two variables explained 80% of the eCF variability in the F treatment, supporting the view that both Prochlorococcus and HNA prokaryotes incorporate leucine in substantial amounts, although this results in relatively low carbon production rates in the oligotrophic ocean. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Direct evidence for the partial reflection of hyaluronan molecules by the lining of rabbit knee joints during trans-synovial flow

PubMed Central

Scott, D; Coleman, P J; Mason, R M; Levick, J R

1998-01-01

In synovial joints hydraulic and turnover studies indicate that the synovial lining may partially reflect large macromolecules like hyaluronan, despite discontinuities in the lining cell layer. The reflection hypothesis was tested directly in the present study. Solutions of high molecular weight hyaluronan were infused at controlled pressures into the cavity of rabbit knees under anaesthesia, at concentrations of 0.2 g l−1 (n = 5), 2 g l−1 (n = 5) and 4 g l−1 (n = 6). Time-averaged trans-synovial flows were 9.6, 4.8 and 2.9 μl min−1, respectively. After 5 h infusion the intra-articular fluid was mixed and sampled. Hyaluronan concentration was determined by size-exclusion chromatography. In all sixteen experiments the hyaluronan concentration in the aspirate was greater than that in the infusate (P = 0.0001, Student's paired t test). The increases averaged 2.28 ± 0.04 times at high filtration rates (0.2 g l−1 infusates; mean ± s.e.m.), 1.60 ± 0.09 times at intermediate filtration rates (2 g l−1 infusates) and 1.26 ± 0.08 times at low filtration rates (4 g l−1 infusates). Between 48 and 95% of the hyaluronan in the filtrand was retained in the joint cavity. The greater retention at 2 g l−1, viz.95%, than at 0.2 g l−1, viz.48%, was attributed to interactions between overlapping molecular domains in the more concentrated solution. It is concluded that synovial interstitial matrix can partially reflect hyaluronan molecules, and thus conserve intra-articular lubricant. PMID:9508822

Impact of Proteinuria and Glomerular Filtration Rate on Risk of Thromboembolism in Atrial Fibrillation: the ATRIA Study

PubMed Central

Go, Alan S.; Fang, Margaret C.; Udaltsova, Natalia; Chang, Yuchiao; Pomernacki, Niela K.; Borowsky, Leila; Singer, Daniel E.

2009-01-01

Background Atrial fibrillation (AF) substantially increases the risk of ischemic stroke but this risk varies among individual patients with AF. Existing risk stratification schemes have limited predictive ability. Chronic kidney disease is a major cardiovascular risk factor, but whether it independently increases the risk for ischemic stroke in persons with AF is unknown. Methods and Results We examined how chronic kidney disease (reduced glomerular filtration rate or proteinuria) affects risk of thromboembolism off anticoagulation in patients with AF. We estimated glomerular filtration rate (eGFR) using the Modification of Diet in Renal Disease equation and proteinuria from urine dipstick results found in laboratory databases. Patient characteristics, warfarin use, and thromboembolic events were ascertained from clinical databases, with validation of thromboembolism by chart review. Results During 33,165 person-years off anticoagulation among 10,908 patients with atrial fibrillation, we observed 676 incident thromboembolic events. After adjustment for known risk factors for stroke and other confounders, proteinuria increased the risk of thromboembolism by 54% (relative risk [RR] 1.54, 1.29 to 1.85) and there was a graded, increased risk of stroke associated with progressively lower level of eGFR compared with eGFR ≥60 (in units of ml/min/1.73 m2): RR 1.16 (95% CI: 0.95−1.40) for eGFR 45−59 and RR 1.39 (95% CI: 1.13−1.71) for eGFR <45 (P=0.0082 for trend). Conclusions . Chronic kidney disease increases the risk of thromboembolism in AF independent of other risk factors. Knowing the level of kidney function and presence of proteinuria may improve risk stratification for decision-making about the use of antithrombotic therapy for stroke prevention in AF. PMID:19255343

Prognostic Nutritional Index and the Risk of Mortality in Patients With Acute Heart Failure.

PubMed

Cheng, Yu-Lun; Sung, Shih-Hsien; Cheng, Hao-Min; Hsu, Pai-Feng; Guo, Chao-Yu; Yu, Wen-Chung; Chen, Chen-Huan

2017-06-25

Nutritional status has been related to clinical outcomes in patients with heart failure. We assessed the association between nutritional status, indexed by prognostic nutritional index (PNI), and survival in patients hospitalized for acute heart failure. A total of 1673 patients (age 76±13 years, 68% men) hospitalized for acute heart failure in a tertiary medical center were analyzed. PNI was calculated as 10×serum albumin (g/dL)+0.005×total lymphocyte count (per mm 3 ). National Death Registry was linked to identify the clinical outcomes of all-cause and cardiovascular death. With increasing tertiles of PNI, age and N-terminal probrain natriuretic peptide decreased, and body mass index, estimated glomerular filtration rate, and hemoglobin increased. During a mean follow-up duration of 31.5 months, a higher PNI tertile was related to better survival free from all-cause and cardiovascular mortality in the total study population and in participants with either reduced or preserved left ventricular ejection fraction. After accounting for age, sex, estimated glomerular filtration rate, left ventricular ejection fraction, serum sodium level, and on-admission systolic blood pressure, PNI was independently associated with cardiovascular death and total mortality (hazard ratio per 1 SD of the natural logarithm of the PNI: 0.76 [95% CI, 0.66-0.87] and 0.79 [95% CI, 0.73-0.87], respectively). In subgroup analyses stratified by age, sex, left ventricular ejection fraction, body mass index, or estimated glomerular filtration rate, PNI was consistently related to mortality. PNI is independently associated with long-term survival in patients hospitalized for acute heart failure with either reduced or preserved left ventricular ejection fraction. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

Comparison of estimated glomerular filtration rate equations for dosing new oral anticoagulants in patients with atrial fibrillation.

PubMed

Manzano-Fernández, Sergio; Andreu-Cayuelas, José M; Marín, Francisco; Orenes-Piñero, Esteban; Gallego, Pilar; Valdés, Mariano; Vicente, Vicente; Lip, Gregory Y H; Roldán, Vanessa

2015-06-01

New oral anticoagulants require dosing adjustment according to renal function. We aimed to determine discordance in hypothetical recommended dosing of these drugs using different estimated glomerular filtration rate equations in patients with atrial fibrillation. Cross-sectional analysis of 910 patients with atrial fibrillation and an indication for oral anticoagulation. The glomerular filtration rate was estimated using the Cockcroft-Gault, Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration equations. For dabigatran, rivaroxaban, and apixaban we identified dose discordance when there was disagreement in the recommended dose based on different equations. Among the overall population, relative to Cockcroft-Gault, discordance in dabigatran dosage was 11.4% for Modification of Diet in Renal Disease and 10% for Chronic Kidney Disease Epidemiology Collaboration, discordance in rivaroxaban dosage was 10% for Modification of Diet in Renal Disease and 8.5% for the Chronic Kidney Disease Epidemiology Collaboration. The lowest discordance was observed for apixaban: 1.4% for Modification of Diet in Renal Disease and 1.5% for the Chronic Kidney Disease Epidemiology Collaboration. In patients with Cockcroft-Gault<60mL/min or elderly patients, discordances in dabigatran and rivaroxaban dosages were higher, ranging from 13.2% to 30.4%. Discordance in apixaban dosage remained<5% in these patients. Discordance in new oral anticoagulation dosages using different equations is frequent, especially among elderly patients with renal impairment. This discordance was higher in dabigatran and rivaroxaban dosages than in apixaban dosages. Further studies are needed to clarify the clinical importance of these discordances and the optimal anticoagulant dosages depending on the use of different equations to estimate renal function. Copyright © 2014 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

Performance in Measurement of Serum Cystatin C by Laboratories Participating in the College of American Pathologists 2014 CYS Survey.

PubMed

Eckfeldt, John H; Karger, Amy B; Miller, W Greg; Rynders, Gregory P; Inker, Lesley A

2015-07-01

Cystatin C is becoming an increasingly popular biomarker for estimating glomerular filtration rate, and accurate measurements of cystatin C concentrations are necessary for accurate estimates of glomerular filtration rate. To assess the accuracy of cystatin C concentration measurements in laboratories participating in the College of American Pathologists CYS Survey. Two fresh frozen serum pools, the first from apparently healthy donors and the second from patients with chronic kidney disease, were prepared and distributed to laboratories participating in the CYS Survey along with the 2 usual processed human plasma samples. Target values were established for each pool by using 2 immunoassays and ERM DA471/IFCC international reference material. For the normal fresh frozen pool (ERM-DA471/IFCC-traceable target of 0.960 mg/L), the all-method mean (SD, % coefficient of variation [CV]) reported by all of the 123 reporting laboratories was 0.894 mg/L (0.128 mg/L, 14.3%). For the chronic kidney disease pool (ERM-DA471/IFCC-traceable target of 2.37 mg/L), the all-method mean (SD, %CV) was 2.258 mg/L (0.288 mg/L, 12.8%). There were substantial method-specific biases (mean milligram per liter reported for the normal pool was 0.780 for Siemens, 0.870 for Gentian, 0.967 for Roche, 1.061 for Diazyme, and 0.970 for other/not specified reagents; and mean milligram per liter reported for the chronic kidney disease pool was 2.052 for Siemens, 2.312 for Gentian, 2.247 for Roche, 2.909 for Diazyme, and 2.413 for other/not specified reagents). Manufacturers need to improve the accuracy of cystatin C measurement procedures if cystatin C is to achieve its full potential as a biomarker for estimating glomerular filtration rate.

[Management of chronic kidney disease guided by the theory of Traditional Chinese Medicine: an experimental study].

PubMed

Wen, Ji; Xie, Xi-Sheng; Zhang, Ming-Hua; Mao, Nan; Zhang, Cheng-Long; Xie, Lin-Shen; Cheng, Yuan; Zhang, Zi-Yuan; Fan, Jun-Ming

2014-01-01

To determine the impact of Traditional Chinese Medicine on patients with chronic kidney disease (CKD). A total of 225 CKD patients in an outpatient department were recruited for this study, among whom 170 received regular Western and Chinese medicine treatments (control group) and 55 received treatments guided by the theory of Traditional Chinese Medicine (experimental group). The effectiveness of the treatments was determined through a pre-post comparison. Significant pre-intervention differences in age (P < 0.01), stage of glomerular filtration rate (GFR) (P = 0.007) and urine protein (P < 0.01) were found between the two groups of patients. But age, gender and proteinuria were not significant predictors on clinical outcomes of the patients in the multivariate regression models. The experimental group had a greater level of decrease in blood urea nitrogen (P < 0.01) and serum creatine (P < 0. 01) than the control group. No significant differences between the groups were found in changes of uric acid (P = 0.475), urine protein (P = 0.058), urine red cells (P = 0.577), and urine white cells (P = 0.01). A greater level of increase in estimated glomerular filtration rate was found in the experimental group compared with the control (P < 0.001). The multivariate linear regression analysis identified group (B = 0.395, P < 0.001) and stage of GFR (B = 0.165, P = 0.008) as significant predictors on the outcomes of treatment. The treatment of CKD patients guided by the theory of Traditional Chinese Medicine can improve renal function through influencing glomerular filtration rate. The effect is more prominent than the regular treatment regime.

Sample Dilution and Bacterial Community Composition Influence Empirical Leucine-to-Carbon Conversion Factors in Surface Waters of the World's Oceans

PubMed Central

Hernando-Morales, Víctor; Cornejo-Castillo, Francisco M.; Alonso-Sáez, Laura; Sarmento, Hugo; Valencia-Vila, Joaquín; Serrano Catalá, Teresa; Hernández-Ruiz, Marta; Varela, Marta M.; Ferrera, Isabel; Gutiérrez Morán, Xosé Anxelu; Gasol, Josep M.

2015-01-01

The transformation of leucine incorporation rates to prokaryotic carbon production rates requires the use of either theoretical or empirically determined conversion factors. Empirical leucine-to-carbon conversion factors (eCFs) vary widely across environments, and little is known about their potential controlling factors. We conducted 10 surface seawater manipulation experiments across the world's oceans, where the growth of the natural prokaryotic assemblages was promoted by filtration (i.e., removal of grazers [F treatment]) or filtration combined with dilution (i.e., also relieving resource competition [FD treatment]). The impact of sunlight exposure was also evaluated in the FD treatments, and we did not find a significant effect on the eCFs. The eCFs varied from 0.09 to 1.47 kg C mol Leu−1 and were significantly lower in the FD than in the F samples. Also, changes in bacterial community composition during the incubations, as assessed by automated ribosomal intergenic spacer analysis (ARISA), were more pronounced in the FD than in the F treatments, compared to unmanipulated controls. Thus, we discourage the common procedure of diluting samples (in addition to filtration) for eCF determination. The eCFs in the filtered treatment were negatively correlated with the initial chlorophyll a concentration, picocyanobacterial abundance (mostly Prochlorococcus), and the percentage of heterotrophic prokaryotes with high nucleic acid content (%HNA). The latter two variables explained 80% of the eCF variability in the F treatment, supporting the view that both Prochlorococcus and HNA prokaryotes incorporate leucine in substantial amounts, although this results in relatively low carbon production rates in the oligotrophic ocean. PMID:26407885

Site suitability for riverbed filtration system in Tanah Merah, Kelantan-A physical model study for turbidity removal

NASA Astrophysics Data System (ADS)

Ghani, Mastura; Adlan, Mohd Nordin; Kamal, Nurul Hana Mokhtar; Aziz, Hamidi Abdul

2017-10-01

A laboratory physical model study on riverbed filtration (RBeF) was conducted to investigate site suitability of soil from Tanah Merah, Kelantan for RBeF. Soil samples were collected and transported to the Geotechnical Engineering Laboratory, Universiti Sains Malaysia for sieve analysis and hydraulic conductivity tests. A physical model was fabricated with gravel packs laid at the bottom of it to cover the screen and then soil sample were placed above gravel pack for 30 cm depth. River water samples from Lubok Buntar, Kedah were used to simulate the effectiveness of RBeF for turbidity removal. Turbidity readings were tested at the inlet and outlet of the filter with specified flow rate. Results from soil characterization show that the soil samples were classified as poorly graded sand with hydraulic conductivity ranged from 7.95 x 10-3 to 6.61 x 10-2 cm/s. Turbidity removal ranged from 44.91% - 92.75% based on the turbidity of water samples before filtration in the range of 33.1-161 NTU. The turbidity of water samples after RBeF could be enhanced up to 2.53 NTU. River water samples with higher turbidity of more than 160 NTU could only reach 50% or less removal by the physical model. Flow rates of the RBeF were in the range of 0.11-1.61 L/min while flow rates at the inlet were set up between 2-4 L/min. Based on the result of soil classification, Tanah Merah site is suitable for RBeF whereas result from physical model study suggested that 30 cm depth of filter media is not sufficient to be used if river water turbidity is higher.

The action of bombesin on the kidney of the anaesthetized dog.

PubMed

Erspamer, V; Melchiorri, P; Sopranzi, N

1973-07-01

1. In the anaesthetized dog bombesin had a potent antidiuretic effect, and sometimes arrested urine flow completely. Threshold doses, by i.v. infusion, were of the order of 0.5-1 (ng/kg)/minute. Antidiuresis was the result of a reduction in glomerular filtration rate provoked by a fall in intraglomerular hydrostatic pressure. This, in its turn, was due to afferent vasoconstriction.2. The spasmogenic effect of bombesin on the smooth muscle of the afferent arterioles was directly demonstrated by the radioactive microspheres technique and indirectly by the (85)Kr washout method and by [(3)H]-p-aminohippurate clearance. The vascular compartment most sensitive to bombesin was that of the outer cortical zone, especially in its external half.3. Filtration fraction decreased under the influence of bombesin, indicating that the effect of the polypeptide on postglomerular arterioles was, if present, only of minor importance.4. At high infusion rates (above 6 (ng/kg)/min), bombesin produced a decrease in [(3)H]-p-aminohippurate extraction. The effect of the polypeptide on fractional distal delivery of sodium varied with the dose: at moderate infusion rates it decreased, at high infusion rates it increased. The total glucose appearing in urine following a glucose load was sharply reduced by bombesin. However, the glomerular filtration rate/maximum tubular glucose transport ratio did not show any appreciable change.5. Afferent vasoconstriction produced by bombesin was accompanied by an intense activation of the renin-angiotensin system, as shown by a conspicuous increase in renin secretion, followed by increases in renin activity and angiotensin II concentration in arterial blood. When bombesin was infused into one renal artery only the infused kidney showed afferent vasoconstriction and increased renin secretion. The time-course of renin secretion produced by bombesin depended upon the rate of infusion of the polypeptide. At low rates an increased renin secretion was observed throughout the infusion period, at high rates two peaks of renin secretion could be seen, one at the beginning of the infusion, the other soon after the infusion had finished.6. The mechanism of action of bombesin is discussed and the interest of the polypeptide as a possible hormonal regulator of the circulation and function of the kidney is pointed out.

Study on the influence on water ecosystem by a lake inflow filtration system

NASA Astrophysics Data System (ADS)

Wu, Sushu; Gao, Shipei; Hu, Xiaodong; Weng, Songgan; Guo, Liuchao

2018-06-01

Lakes play important roles in the economic-social sustainable development. However, due to unreasonable development and urbanization in recent years, lake water pollution and ecological degradation have occurred in China. The improvement of the lake inflow water quality is very important. A filtration system includes Gravel filtering system, Aquatic plant area and Ecological bag area was established. The test river is one of the typical lake inflow river and located in the river network in the Chang Dang lake, China. Water quality, zooplankton and phytoplankton in the inflow river were observed form July to mid-August in order to analyze the general process. The average removal rate of NH3-N (ammonia nitrogen) TN (total nitrogen) and TP (total phosphorus) is 28.33, 25.76 and 24.43 %, respectively. The Pantle-Buck method was used to evaluate the water quality and the B/T index was used to evaluate the nutrition situation. The B/T values were reduced by 20 % and the SI pollution index was reduced by 11.8 %. Therefore, a positive effect on the water's ecological restoration was achieved by the filtration system.

Anaerobic digestion for treatment of stillage from cellulosic bioethanol production.

PubMed

Tian, Zhuoli; Mohan, Gayathri Ram; Ingram, Lonnie; Pullammanappallil, Pratap

2013-09-01

Thermophilic anaerobic digestion of stillage from a cellulosic ethanol process that uses sugarcane bagasse as feedstock was investigated. A biochemical methane potential (BMP) of 200 ml CH4 at STP (g VS)(-1) was obtained. The whole stillage was separated into two fractions: a fraction retained on 0.5 mm screen called residue and a fraction passing through 0.5 mm screen called filtrate. About 70% of total methane yield of stillage was produced from the filtrate. The filtrate was anaerobically digested in a 15 L semi-continuously fed digester operated for 91 days at HRTs of 21 and 14 days and organic loading rate (OLR) of 1.85 and 2.39 g COD L(-1) d(-1). The methane yield from the stillage from the digester was about 90% of the yield from the BMP assays. The influent soluble COD (sCOD) was reduced from between 35.4 and 38.8 g COD (L(-1)) to between 7.5 and 8 g COD (L(-1)). Copyright © 2013 Elsevier Ltd. All rights reserved.

Accelerated recovery from nephrotic syndrome with acute renal failure by double filtration plasmapheresis in a patient with lupus podocytopathy.

PubMed

Iwazu, Yoshitaka; Akimoto, Tetsu; Izawa, Sayoko; Inoue, Makoto; Muto, Shigeaki; Ando, Yasuhiro; Iwazu, Kana; Fukushima, Noriyoshi; Yumura, Wako; Kusano, Eiji

2012-06-01

We describe a case of an adult female who presented with nephrotic syndrome. She was diagnosed with systemic lupus erythematosus with serum antinuclear antibodies, leucopenia with lymphopenia, butterfly erythema, and nephrotic syndrome. Renal biopsy revealed normal glomeruli with diffuse effacement of the foot processes, consistent with lupus podocytopathy. Although human albumin replacement was performed initially, acute renal failure developed rapidly. Therefore, she was treated with double filtration plasmapheresis (DFPP) in addition to oral steroid. After steroid therapy combined with DFPP, the renal function and proteinuria improved rapidly. Although the impact of DFPP on the treatment of lupus nephritis remains to be delineated, our observations suggest that DFPP in lupus podocytopathy played a pivotal role in facilitating the early recovery from renal injuries. Because of the rapid improvement of renal function without any change in body weight by DFPP, acute renal failure in the setting of lupus podocytopathy might contribute to an alternative pathophysiological factor for the diminished glomerular filtration rate, similar to that observed in the setting of idiopathic minimal change glomerulopathy.

PROCESS OF EXTRACTING URANIUM AND RADIUM FROM ORES

DOEpatents

Sawyer, C.W.; Handley, R.W.

1959-07-14

A process is presented for extracting uranium and radium values from a uranium ore which comprises leaching the ore with a ferric chloride solution at an elevated temperature of above 50 deg C and at a pH less than 4; separating the ore residue from the leaching solution by filtration; precipitating the excess ferric iron present at a pH of less than 5 by adding CaCO/sub 3/ to the filtrate; separating the precipitate by filtration; precipitating the uranium present in the filtrate at a Ph less than 6 by adding BaCO/sub 3/ to the filtrate; separating the precipitate by filtration; and precipitating the radium present in the filtrate by adding H/sub 2/SO/sub 4/ to the filtrate.

Assessment of Plasma and NGAL for the Early Prediction of Acute Kidney Injury After Cardiac Surgery in Adults Study

ClinicalTrials.gov

2017-04-24

Acute Kidney Injury (AKI); Chronic Kidney Disease (CKD); End Stage Renal Disease (ESRD); Estimated Glomerular Filtration Rate (eGFR); Neutrophil Gelatinase-associated Lipocalin (NGAL); Serum Creatinine (SCr); Urine Creatinine (UCr); Urine Albumin (UAlb)

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function.

PubMed

Pattaro, Cristian; Teumer, Alexander; Gorski, Mathias; Chu, Audrey Y; Li, Man; Mijatovic, Vladan; Garnaas, Maija; Tin, Adrienne; Sorice, Rossella; Li, Yong; Taliun, Daniel; Olden, Matthias; Foster, Meredith; Yang, Qiong; Chen, Ming-Huei; Pers, Tune H; Johnson, Andrew D; Ko, Yi-An; Fuchsberger, Christian; Tayo, Bamidele; Nalls, Michael; Feitosa, Mary F; Isaacs, Aaron; Dehghan, Abbas; d'Adamo, Pio; Adeyemo, Adebowale; Dieffenbach, Aida Karina; Zonderman, Alan B; Nolte, Ilja M; van der Most, Peter J; Wright, Alan F; Shuldiner, Alan R; Morrison, Alanna C; Hofman, Albert; Smith, Albert V; Dreisbach, Albert W; Franke, Andre; Uitterlinden, Andre G; Metspalu, Andres; Tonjes, Anke; Lupo, Antonio; Robino, Antonietta; Johansson, Åsa; Demirkan, Ayse; Kollerits, Barbara; Freedman, Barry I; Ponte, Belen; Oostra, Ben A; Paulweber, Bernhard; Krämer, Bernhard K; Mitchell, Braxton D; Buckley, Brendan M; Peralta, Carmen A; Hayward, Caroline; Helmer, Catherine; Rotimi, Charles N; Shaffer, Christian M; Müller, Christian; Sala, Cinzia; van Duijn, Cornelia M; Saint-Pierre, Aude; Ackermann, Daniel; Shriner, Daniel; Ruggiero, Daniela; Toniolo, Daniela; Lu, Yingchang; Cusi, Daniele; Czamara, Darina; Ellinghaus, David; Siscovick, David S; Ruderfer, Douglas; Gieger, Christian; Grallert, Harald; Rochtchina, Elena; Atkinson, Elizabeth J; Holliday, Elizabeth G; Boerwinkle, Eric; Salvi, Erika; Bottinger, Erwin P; Murgia, Federico; Rivadeneira, Fernando; Ernst, Florian; Kronenberg, Florian; Hu, Frank B; Navis, Gerjan J; Curhan, Gary C; Ehret, George B; Homuth, Georg; Coassin, Stefan; Thun, Gian-Andri; Pistis, Giorgio; Gambaro, Giovanni; Malerba, Giovanni; Montgomery, Grant W; Eiriksdottir, Gudny; Jacobs, Gunnar; Li, Guo; Wichmann, H-Erich; Campbell, Harry; Schmidt, Helena; Wallaschofski, Henri; Völzke, Henry; Brenner, Hermann; Kroemer, Heyo K; Kramer, Holly; Lin, Honghuang; Leach, I Mateo; Ford, Ian; Guessous, Idris; Rudan, Igor; Prokopenko, Inga; Borecki, Ingrid; Heid, Iris M; Kolcic, Ivana; Persico, Ivana; Jukema, J Wouter; Wilson, James F; Felix, Janine F; Divers, Jasmin; Lambert, Jean-Charles; Stafford, Jeanette M; Gaspoz, Jean-Michel; Smith, Jennifer A; Faul, Jessica D; Wang, Jie Jin; Ding, Jingzhong; Hirschhorn, Joel N; Attia, John; Whitfield, John B; Chalmers, John; Viikari, Jorma; Coresh, Josef; Denny, Joshua C; Karjalainen, Juha; Fernandes, Jyotika K; Endlich, Karlhans; Butterbach, Katja; Keene, Keith L; Lohman, Kurt; Portas, Laura; Launer, Lenore J; Lyytikäinen, Leo-Pekka; Yengo, Loic; Franke, Lude; Ferrucci, Luigi; Rose, Lynda M; Kedenko, Lyudmyla; Rao, Madhumathi; Struchalin, Maksim; Kleber, Marcus E; Cavalieri, Margherita; Haun, Margot; Cornelis, Marilyn C; Ciullo, Marina; Pirastu, Mario; de Andrade, Mariza; McEvoy, Mark A; Woodward, Mark; Adam, Martin; Cocca, Massimiliano; Nauck, Matthias; Imboden, Medea; Waldenberger, Melanie; Pruijm, Menno; Metzger, Marie; Stumvoll, Michael; Evans, Michele K; Sale, Michele M; Kähönen, Mika; Boban, Mladen; Bochud, Murielle; Rheinberger, Myriam; Verweij, Niek; Bouatia-Naji, Nabila; Martin, Nicholas G; Hastie, Nick; Probst-Hensch, Nicole; Soranzo, Nicole; Devuyst, Olivier; Raitakari, Olli; Gottesman, Omri; Franco, Oscar H; Polasek, Ozren; Gasparini, Paolo; Munroe, Patricia B; Ridker, Paul M; Mitchell, Paul; Muntner, Paul; Meisinger, Christa; Smit, Johannes H; Kovacs, Peter; Wild, Philipp S; Froguel, Philippe; Rettig, Rainer; Mägi, Reedik; Biffar, Reiner; Schmidt, Reinhold; Middelberg, Rita P S; Carroll, Robert J; Penninx, Brenda W; Scott, Rodney J; Katz, Ronit; Sedaghat, Sanaz; Wild, Sarah H; Kardia, Sharon L R; Ulivi, Sheila; Hwang, Shih-Jen; Enroth, Stefan; Kloiber, Stefan; Trompet, Stella; Stengel, Benedicte; Hancock, Stephen J; Turner, Stephen T; Rosas, Sylvia E; Stracke, Sylvia; Harris, Tamara B; Zeller, Tanja; Zemunik, Tatijana; Lehtimäki, Terho; Illig, Thomas; Aspelund, Thor; Nikopensius, Tiit; Esko, Tonu; Tanaka, Toshiko; Gyllensten, Ulf; Völker, Uwe; Emilsson, Valur; Vitart, Veronique; Aalto, Ville; Gudnason, Vilmundur; Chouraki, Vincent; Chen, Wei-Min; Igl, Wilmar; März, Winfried; Koenig, Wolfgang; Lieb, Wolfgang; Loos, Ruth J F; Liu, Yongmei; Snieder, Harold; Pramstaller, Peter P; Parsa, Afshin; O'Connell, Jeffrey R; Susztak, Katalin; Hamet, Pavel; Tremblay, Johanne; de Boer, Ian H; Böger, Carsten A; Goessling, Wolfram; Chasman, Daniel I; Köttgen, Anna; Kao, W H Linda; Fox, Caroline S

2016-01-21

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways.

[Acute toxicity effects of three red tide algae on Brachionus plicatilis].

PubMed

Zhou, Wen-Li; Xiao, Hui; Wang, You; Zhai, Hong-Chang; Tang, Xue-Xi

2008-11-01

Acute toxicity testing method was used to study effects of different density of Prorocentrum donghaiense, Heterosigma akashiwo and Alexandrium tamarense on mortality rates and population growth parameter of Brachionus plicatilis under controlled experimental conditions. Results showed that 24 h LC50 values of Prorocentrum donghaiense, Heterosigma akashiwo and Alexandrium tamarense treatment to mortality rate of Brachionus plicatilis were 3.56, 1.21 and 0.49 (x 10(4) cells/mL) respectively. Marked density effects were presented when three species of red tide microalga showed their toxicity to Brachionus plicatilis. There were significant inhibitory effects on Brachionus plicatilis when it was exposed to cells of Prorocentrum donghaiense at the concentration of 10(4) cells/mL, filtrate and cell contents of Heterosigma akashiwo at the concentration of 10(5) cells/mL, and cells, filtrate and cell contents of Alexandrium tamarense at the concentration of 10(3) cells/mL respectively. Inhibitory effects of three species of microalga on Brachionus plicatilis were enhanced with increasing of microalgal density.

Genetic associations at 53 loci highlight cell types and biological pathways relevant for kidney function

PubMed Central

Pattaro, Cristian; Teumer, Alexander; Gorski, Mathias; Chu, Audrey Y.; Li, Man; Mijatovic, Vladan; Garnaas, Maija; Tin, Adrienne; Sorice, Rossella; Li, Yong; Taliun, Daniel; Olden, Matthias; Foster, Meredith; Yang, Qiong; Chen, Ming-Huei; Pers, Tune H.; Johnson, Andrew D.; Ko, Yi-An; Fuchsberger, Christian; Tayo, Bamidele; Nalls, Michael; Feitosa, Mary F.; Isaacs, Aaron; Dehghan, Abbas; d'Adamo, Pio; Adeyemo, Adebowale; Dieffenbach, Aida Karina; Zonderman, Alan B.; Nolte, Ilja M.; van der Most, Peter J.; Wright, Alan F.; Shuldiner, Alan R.; Morrison, Alanna C.; Hofman, Albert; Smith, Albert V.; Dreisbach, Albert W.; Franke, Andre; Uitterlinden, Andre G.; Metspalu, Andres; Tonjes, Anke; Lupo, Antonio; Robino, Antonietta; Johansson, Åsa; Demirkan, Ayse; Kollerits, Barbara; Freedman, Barry I.; Ponte, Belen; Oostra, Ben A.; Paulweber, Bernhard; Krämer, Bernhard K.; Mitchell, Braxton D.; Buckley, Brendan M.; Peralta, Carmen A.; Hayward, Caroline; Helmer, Catherine; Rotimi, Charles N.; Shaffer, Christian M.; Müller, Christian; Sala, Cinzia; van Duijn, Cornelia M.; Saint-Pierre, Aude; Ackermann, Daniel; Shriner, Daniel; Ruggiero, Daniela; Toniolo, Daniela; Lu, Yingchang; Cusi, Daniele; Czamara, Darina; Ellinghaus, David; Siscovick, David S.; Ruderfer, Douglas; Gieger, Christian; Grallert, Harald; Rochtchina, Elena; Atkinson, Elizabeth J.; Holliday, Elizabeth G.; Boerwinkle, Eric; Salvi, Erika; Bottinger, Erwin P.; Murgia, Federico; Rivadeneira, Fernando; Ernst, Florian; Kronenberg, Florian; Hu, Frank B.; Navis, Gerjan J.; Curhan, Gary C.; Ehret, George B.; Homuth, Georg; Coassin, Stefan; Thun, Gian-Andri; Pistis, Giorgio; Gambaro, Giovanni; Malerba, Giovanni; Montgomery, Grant W.; Eiriksdottir, Gudny; Jacobs, Gunnar; Li, Guo; Wichmann, H-Erich; Campbell, Harry; Schmidt, Helena; Wallaschofski, Henri; Völzke, Henry; Brenner, Hermann; Kroemer, Heyo K.; Kramer, Holly; Lin, Honghuang; Leach, I. Mateo; Ford, Ian; Guessous, Idris; Rudan, Igor; Prokopenko, Inga; Borecki, Ingrid; Heid, Iris M.; Kolcic, Ivana; Persico, Ivana; Jukema, J. Wouter; Wilson, James F.; Felix, Janine F.; Divers, Jasmin; Lambert, Jean-Charles; Stafford, Jeanette M.; Gaspoz, Jean-Michel; Smith, Jennifer A.; Faul, Jessica D.; Wang, Jie Jin; Ding, Jingzhong; Hirschhorn, Joel N.; Attia, John; Whitfield, John B.; Chalmers, John; Viikari, Jorma; Coresh, Josef; Denny, Joshua C.; Karjalainen, Juha; Fernandes, Jyotika K.; Endlich, Karlhans; Butterbach, Katja; Keene, Keith L.; Lohman, Kurt; Portas, Laura; Launer, Lenore J.; Lyytikäinen, Leo-Pekka; Yengo, Loic; Franke, Lude; Ferrucci, Luigi; Rose, Lynda M.; Kedenko, Lyudmyla; Rao, Madhumathi; Struchalin, Maksim; Kleber, Marcus E.; Cavalieri, Margherita; Haun, Margot; Cornelis, Marilyn C.; Ciullo, Marina; Pirastu, Mario; de Andrade, Mariza; McEvoy, Mark A.; Woodward, Mark; Adam, Martin; Cocca, Massimiliano; Nauck, Matthias; Imboden, Medea; Waldenberger, Melanie; Pruijm, Menno; Metzger, Marie; Stumvoll, Michael; Evans, Michele K.; Sale, Michele M.; Kähönen, Mika; Boban, Mladen; Bochud, Murielle; Rheinberger, Myriam; Verweij, Niek; Bouatia-Naji, Nabila; Martin, Nicholas G.; Hastie, Nick; Probst-Hensch, Nicole; Soranzo, Nicole; Devuyst, Olivier; Raitakari, Olli; Gottesman, Omri; Franco, Oscar H.; Polasek, Ozren; Gasparini, Paolo; Munroe, Patricia B.; Ridker, Paul M.; Mitchell, Paul; Muntner, Paul; Meisinger, Christa; Smit, Johannes H.; Abecasis, Goncalo R.; Adair, Linda S.; Alexander, Myriam; Altshuler, David; Amin, Najaf; Arking, Dan E.; Arora, Pankaj; Aulchenko, Yurii; Bakker, Stephan J. L.; Bandinelli, Stefania; Barroso, Ines; Beckmann, Jacques S.; Beilby, John P.; Bergman, Richard N.; Bergmann, Sven; Bis, Joshua C.; Boehnke, Michael; Bonnycastle, Lori L.; Bornstein, Stefan R.; Bots, Michiel L.; Bragg-Gresham, Jennifer L.; Brand, Stefan-Martin; Brand, Eva; Braund, Peter S.; Brown, Morris J.; Burton, Paul R.; Casas, Juan P.; Caulfield, Mark J.; Chakravarti, Aravinda; Chambers, John C.; Chandak, Giriraj R.; Chang, Yen-Pei C.; Charchar, Fadi J.; Chaturvedi, Nish; Shin Cho, Yoon; Clarke, Robert; Collins, Francis S.; Collins, Rory; Connell, John M.; Cooper, Jackie A.; Cooper, Matthew N.; Cooper, Richard S.; Corsi, Anna Maria; Dörr, Marcus; Dahgam, Santosh; Danesh, John; Smith, George Davey; Day, Ian N. M.; Deloukas, Panos; Denniff, Matthew; Dominiczak, Anna F.; Dong, Yanbin; Doumatey, Ayo; Elliott, Paul; Elosua, Roberto; Erdmann, Jeanette; Eyheramendy, Susana; Farrall, Martin; Fava, Cristiano; Forrester, Terrence; Fowkes, F. Gerald R.; Fox, Ervin R.; Frayling, Timothy M.; Galan, Pilar; Ganesh, Santhi K.; Garcia, Melissa; Gaunt, Tom R.; Glazer, Nicole L.; Go, Min Jin; Goel, Anuj; Grässler, Jürgen; Grobbee, Diederick E.; Groop, Leif; Guarrera, Simonetta; Guo, Xiuqing; Hadley, David; Hamsten, Anders; Han, Bok-Ghee; Hardy, Rebecca; Hartikainen, Anna-Liisa; Heath, Simon; Heckbert, Susan R.; Hedblad, Bo; Hercberg, Serge; Hernandez, Dena; Hicks, Andrew A.; Hilton, Gina; Hingorani, Aroon D.; Bolton, Judith A Hoffman; Hopewell, Jemma C.; Howard, Philip; Humphries, Steve E.; Hunt, Steven C.; Hveem, Kristian; Ikram, M. Arfan; Islam, Muhammad; Iwai, Naoharu; Jarvelin, Marjo-Riitta; Jackson, Anne U.; Jafar, Tazeen H.; Janipalli, Charles S.; Johnson, Toby; Kathiresan, Sekar; Khaw, Kay-Tee; Kim, Hyung-Lae; Kinra, Sanjay; Kita, Yoshikuni; Kivimaki, Mika; Kooner, Jaspal S.; Kumar, M. J. Kranthi; Kuh, Diana; Kulkarni, Smita R.; Kumari, Meena; Kuusisto, Johanna; Kuznetsova, Tatiana; Laakso, Markku; Laan, Maris; Laitinen, Jaana; Lakatta, Edward G.; Langefeld, Carl D.; Larson, Martin G.; Lathrop, Mark; Lawlor, Debbie A.; Lawrence, Robert W.; Lee, Jong-Young; Lee, Nanette R.; Levy, Daniel; Li, Yali; Longstreth, Will T.; Luan, Jian'an; Lucas, Gavin; Ludwig, Barbara; Mangino, Massimo; Mani, K. Radha; Marmot, Michael G.; Mattace-Raso, Francesco U. S.; Matullo, Giuseppe; McArdle, Wendy L.; McKenzie, Colin A.; Meitinger, Thomas; Melander, Olle; Meneton, Pierre; Meschia, James F.; Miki, Tetsuro; Milaneschi, Yuri; Mohlke, Karen L.; Mooser, Vincent; Morken, Mario A.; Morris, Richard W.; Mosley, Thomas H.; Najjar, Samer; Narisu, Narisu; Newton-Cheh, Christopher; Nguyen, Khanh-Dung Hoang; Nilsson, Peter; Nyberg, Fredrik; O'Donnell, Christopher J.; Ogihara, Toshio; Ohkubo, Takayoshi; Okamura, Tomonori; Ong, RickTwee-Hee; Ongen, Halit; Onland-Moret, N. Charlotte; O'Reilly, Paul F.; Org, Elin; Orru, Marco; Palmas, Walter; Palmen, Jutta; Palmer, Lyle J.; Palmer, Nicholette D.; Parker, Alex N.; Peden, John F.; Peltonen, Leena; Perola, Markus; Pihur, Vasyl; Platou, Carl G. P.; Plump, Andrew; Prabhakaran, Dorairajan; Psaty, Bruce M.; Raffel, Leslie J.; Rao, Dabeeru C.; Rasheed, Asif; Ricceri, Fulvio; Rice, Kenneth M.; Rosengren, Annika; Rotter, Jerome I.; Rudock, Megan E.; Sõber, Siim; Salako, Tunde; Saleheen, Danish; Salomaa, Veikko; Samani, Nilesh J.; Schwartz, Steven M.; Schwarz, Peter E. H.; Scott, Laura J.; Scott, James; Scuteri, Angelo; Sehmi, Joban S.; Seielstad, Mark; Seshadri, Sudha; Sharma, Pankaj; Shaw-Hawkins, Sue; Shi, Gang; Shrine, Nick R. G.; Sijbrands, Eric J. G.; Sim, Xueling; Singleton, Andrew; Sjögren, Marketa; Smith, Nicholas L.; Artigas, Maria Soler; Spector, Tim D.; Staessen, Jan A.; Stancakova, Alena; Steinle, Nanette I.; Strachan, David P.; Stringham, Heather M.; Sun, Yan V.; Swift, Amy J.; Tabara, Yasuharu; Tai, E-Shyong; Talmud, Philippa J.; Taylor, Andrew; Terzic, Janos; Thelle, Dag S.; Tobin, Martin D.; Tomaszewski, Maciej; Tripathy, Vikal; Tuomilehto, Jaakko; Tzoulaki, Ioanna; Uda, Manuela; Ueshima, Hirotsugu; Uiterwaal, Cuno S. P. M.; Umemura, Satoshi; van der Harst, Pim; van der Schouw, Yvonne T.; van Gilst, Wiek H.; Vartiainen, Erkki; Vasan, Ramachandran S.; Veldre, Gudrun; Verwoert, Germaine C.; Viigimaa, Margus; Vinay, D. G.; Vineis, Paolo; Voight, Benjamin F.; Vollenweider, Peter; Wagenknecht, Lynne E.; Wain, Louise V.; Wang, Xiaoling; Wang, Thomas J.; Wareham, Nicholas J.; Watkins, Hugh; Weder, Alan B.; Whincup, Peter H.; Wiggins, Kerri L.; Witteman, Jacqueline C. M.; Wong, Andrew; Wu, Ying; Yajnik, Chittaranjan S.; Yao, Jie; Young, J. H.; Zelenika, Diana; Zhai, Guangju; Zhang, Weihua; Zhang, Feng; Zhao, Jing Hua; Zhu, Haidong; Zhu, Xiaofeng; Zitting, Paavo; Zukowska-Szczechowska, Ewa; Okada, Yukinori; Wu, Jer-Yuarn; Gu, Dongfeng; Takeuchi, Fumihiko; Takahashi, Atsushi; Maeda, Shiro; Tsunoda, Tatsuhiko; Chen, Peng; Lim, Su-Chi; Wong, Tien-Yin; Liu, Jianjun; Young, Terri L.; Aung, Tin; Teo, Yik-Ying; Kim, Young Jin; Kang, Daehee; Chen, Chien-Hsiun; Tsai, Fuu-Jen; Chang, Li-Ching; Fann, S. -J. Cathy; Mei, Hao; Hixson, James E.; Chen, Shufeng; Katsuya, Tomohiro; Isono, Masato; Albrecht, Eva; Yamamoto, Kazuhiko; Kubo, Michiaki; Nakamura, Yusuke; Kamatani, Naoyuki; Kato, Norihiro; He, Jiang; Chen, Yuan-Tsong; Tanaka, Toshihiro; Reilly, Muredach P; Schunkert, Heribert; Assimes, Themistocles L.; Hall, Alistair; Hengstenberg, Christian; König, Inke R.; Laaksonen, Reijo; McPherson, Ruth; Thompson, John R.; Thorsteinsdottir, Unnur; Ziegler, Andreas; Absher, Devin; Chen, Li; Cupples13, L. Adrienne; Halperin, Eran; Li, Mingyao; Musunuru, Kiran; Preuss, Michael; Schillert, Arne; Thorleifsson, Gudmar; Wells, George A.; Holm, Hilma; Roberts, Robert; Stewart, Alexandre F. R.; Fortmann, Stephen; Go, Alan; Hlatky, Mark; Iribarren, Carlos; Knowles, Joshua; Myers, Richard; Quertermous, Thomas; Sidney, Steven; Risch, Neil; Tang, Hua; Blankenberg, Stefan; Schnabel, Renate; Sinning, Christoph; Lackner, Karl J.; Tiret, Laurence; Nicaud, Viviane; Cambien, Francois; Bickel, Christoph; Rupprecht, Hans J.; Perret, Claire; Proust, Carole; Münzel, Thomas F.; Barbalic, Maja; Chen, Ida Yii-Der; Demissie-Banjaw, Serkalem; Folsom, Aaron; Lumley, Thomas; Marciante, Kristin; Taylor, Kent D.; Volcik, Kelly; Gretarsdottir, Solveig; Gulcher, Jeffrey R.; Kong, Augustine; Stefansson, Kari; Thorgeirsson, Gudmundur; Andersen, Karl; Fischer, Marcus; Grosshennig, Anika; Linsel-Nitschke, Patrick; Stark, Klaus; Schreiber, Stefan; Aherrahrou, Zouhair; Bruse, Petra; Doering, Angela; Klopp, Norman; Diemert, Patrick; Loley, Christina; Medack, Anja; Nahrstedt, Janja; Peters, Annette; Wagner, Arnika K.; Willenborg, Christina; Böhm, Bernhard O.; Dobnig, Harald; Grammer, Tanja B.; Hoffmann, Michael M.; Meinitzer, Andreas; Winkelmann, Bernhard R.; Pilz, Stefan; Renner, Wilfried; Scharnagl, Hubert; Stojakovic, Tatjana; Tomaschitz, Andreas; Winkler, Karl; Guiducci, Candace; Burtt, Noel; Gabriel, Stacey B.; Dandona, Sonny; Jarinova, Olga; Qu, Liming; Wilensky, Robert; Matthai, William; Hakonarson, Hakon H.; Devaney, Joe; Burnett, Mary Susan; Pichard, Augusto D.; Kent, Kenneth M.; Satler, Lowell; Lindsay, Joseph M.; Waksman, Ron; Knouff, Christopher W.; Waterworth, Dawn M.; Walker, Max C.; Epstein, Stephen E.; Rader, Daniel J.; Nelson, Christopher P.; Wright, Benjamin J.; Balmforth, Anthony J.; Ball, Stephen G.; Loehr, Laura R.; Rosamond, Wayne D.; Benjamin, Emelia; Haritunians, Talin; Couper, David; Murabito, Joanne; Wang, Ying A.; Stricker, Bruno H.; Chang, Patricia P.; Willerson, James T.; Felix, Stephan B.; Watzinger, Norbert; Aragam, Jayashri; Zweiker, Robert; Lind, Lars; Rodeheffer, Richard J.; Greiser, Karin Halina; Deckers, Jaap W.; Stritzke, Jan; Ingelsson, Erik; Kullo, Iftikhar; Haerting, Johannes; Reffelmann, Thorsten; Redfield, Margaret M.; Werdan, Karl; Mitchell, Gary F.; Arnett, Donna K.; Gottdiener, John S.; Blettner, Maria; Friedrich, Nele; Kovacs, Peter; Wild, Philipp S.; Froguel, Philippe; Rettig, Rainer; Mägi, Reedik; Biffar, Reiner; Schmidt, Reinhold; Middelberg, Rita P. S.; Carroll, Robert J.; Penninx, Brenda W.; Scott, Rodney J.; Katz, Ronit; Sedaghat, Sanaz; Wild, Sarah H.; Kardia, Sharon L. R.; Ulivi, Sheila; Hwang, Shih-Jen; Enroth, Stefan; Kloiber, Stefan; Trompet, Stella; Stengel, Benedicte; Hancock, Stephen J.; Turner, Stephen T.; Rosas, Sylvia E.; Stracke, Sylvia; Harris, Tamara B.; Zeller, Tanja; Zemunik, Tatijana; Lehtimäki, Terho; Illig, Thomas; Aspelund, Thor; Nikopensius, Tiit; Esko, Tonu; Tanaka, Toshiko; Gyllensten, Ulf; Völker, Uwe; Emilsson, Valur; Vitart, Veronique; Aalto, Ville; Gudnason, Vilmundur; Chouraki, Vincent; Chen, Wei-Min; Igl, Wilmar; März, Winfried; Koenig, Wolfgang; Lieb, Wolfgang; Loos, Ruth J. F.; Liu, Yongmei; Snieder, Harold; Pramstaller, Peter P.; Parsa, Afshin; O'Connell, Jeffrey R.; Susztak, Katalin; Hamet, Pavel; Tremblay, Johanne; de Boer, Ian H.; Böger, Carsten A.; Goessling, Wolfram; Chasman, Daniel I.; Köttgen, Anna; Kao, W. H. Linda; Fox, Caroline S.

2016-01-01

Reduced glomerular filtration rate defines chronic kidney disease and is associated with cardiovascular and all-cause mortality. We conducted a meta-analysis of genome-wide association studies for estimated glomerular filtration rate (eGFR), combining data across 133,413 individuals with replication in up to 42,166 individuals. We identify 24 new and confirm 29 previously identified loci. Of these 53 loci, 19 associate with eGFR among individuals with diabetes. Using bioinformatics, we show that identified genes at eGFR loci are enriched for expression in kidney tissues and in pathways relevant for kidney development and transmembrane transporter activity, kidney structure, and regulation of glucose metabolism. Chromatin state mapping and DNase I hypersensitivity analyses across adult tissues demonstrate preferential mapping of associated variants to regulatory regions in kidney but not extra-renal tissues. These findings suggest that genetic determinants of eGFR are mediated largely through direct effects within the kidney and highlight important cell types and biological pathways. PMID:26831199

Optimization of elutriation device for filtration of microplastic particles from sediment.

PubMed

Zhu, X

2015-03-15

The increasing presence of plastic pollution in marine ecosystems has become a major concern. In the environment, plastics break down into smaller and smaller pieces of microplastics. Methods of microplastic recovery are needed to reduce the dangers they can pose to a variety of organisms. An elutriation device was manufactured and optimized to achieve maximum microplastic recovery. The parameters flow rate and diameter of elutriation column were varied and their domain of variation was determined. A composite factorial experimental design was generated using MODDE 10.1 and was undergone. The optimal values of flow rate and column diameter were determined to be 385 L h(-1) and 5.06 cm respectively, under constraints, to achieve a maximum feasible microplastics recovery percentage of 50.2%. The elutriation process can be improved through further testing, and can be tested in the field to compare its efficiency to that of manual microplastics filtration. Copyright © 2015 Elsevier Ltd. All rights reserved.

Kidney Response to the Spectrum of Diet-Induced Acid Stress

PubMed Central

Goraya, Nimrit; Wesson, Donald E.

2018-01-01

Chronic ingestion of the acid (H+)-producing diets that are typical of developed societies appears to pose a long-term threat to kidney health. Mechanisms employed by kidneys to excrete this high dietary H+ load appear to cause long-term kidney injury when deployed over many years. In addition, cumulative urine H+ excretion is less than the cumulative increment in dietary H+, consistent with H+ retention. This H+ retention associated with the described high dietary H+ worsens as the glomerular filtration rate (GFR) declines which further exacerbates kidney injury. Modest H+ retention does not measurably change plasma acid–base parameters but, nevertheless, causes kidney injury and might contribute to progressive nephropathy. Current clinical methods do not detect H+ retention in its early stages but the condition manifests as metabolic acidosis as it worsens, with progressive decline of the glomerular filtration rate. We discuss this spectrum of H+ injury, which we characterize as “H+ stress”, and the emerging evidence that high dietary H+ constitutes a threat to long-term kidney health. PMID:29751620

Neural control of renal tubular sodium reabsorption of the dog.

PubMed

DiBona, G F

1978-04-01

The evidence supporting a role for direct neurogenic control of renal tubular sodium reabsorption is reviewed. Electron microscopic and fluorescence histochemical studies demonstrate adrenergic nerve terminals in direct contact with basement membranes of mammalian renal tubular epithelial cells. Low level direct or baroreceptor reflex stimulation of renal sympathetic nerves produces an increase in renal tubular sodium reabsorption without alterations in glomerular filtration rate, renal blood flow, or intrarenal distribution of blood flow. The antinatriuresis is prevented by prior treatment of the kidney with guanethidine or phenoxybenzamine. Possible indirect mediation of the antinatriuresis by other humoral agents known to be released from the kidney upon renal nerve stimulation (angiotensin II, prostaglandin) was excluded by experiments with appropriate blocking agents. Reflex diminutions in renal nerve activity (left atrial distention, stellate ganglion stimulation) produce a decrease in renal tubular sodium reabsorption independent of glomerular filtration rate or renal blood flow. The anatomically described adrenergic innervation of the renal tubules participates in the direct regulation of renal tubular sodium reabsorption.

Evaluation of a Combined Cyclone and Gas Filtration System for Particulate Removal in the Gasification Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rizzo, Jeffrey J.

2010-04-30

The Wabash gasification facility, owned and operated by sgSolutions LLC, is one of the largest single train solid fuel gasification facilities in the world capable of transforming 2,000 tons per day of petroleum coke or 2,600 tons per day of bituminous coal into synthetic gas for electrical power generation. The Wabash plant utilizes Phillips66 proprietary E-Gas (TM) Gasification Process to convert solid fuels such as petroleum coke or coal into synthetic gas that is fed to a combined cycle combustion turbine power generation facility. During plant startup in 1995, reliability issues were realized in the gas filtration portion of themore » gasification process. To address these issues, a slipstream test unit was constructed at the Wabash facility to test various filter designs, materials and process conditions for potential reliability improvement. The char filtration slipstream unit provided a way of testing new materials, maintenance procedures, and process changes without the risk of stopping commercial production in the facility. It also greatly reduced maintenance expenditures associated with full scale testing in the commercial plant. This char filtration slipstream unit was installed with assistance from the United States Department of Energy (built under DOE Contract No. DE-FC26-97FT34158) and began initial testing in November of 1997. It has proven to be extremely beneficial in the advancement of the E-Gas (TM) char removal technology by accurately predicting filter behavior and potential failure mechanisms that would occur in the commercial process. After completing four (4) years of testing various filter types and configurations on numerous gasification feed stocks, a decision was made to investigate the economic and reliability effects of using a particulate removal gas cyclone upstream of the current gas filtration unit. A paper study had indicated that there was a real potential to lower both installed capital and operating costs by implementing a char cyclonefiltration hybrid unit in the E-Gas (TM) gasification process. These reductions would help to keep the E-Gas (TM) technology competitive among other coal-fired power generation technologies. The Wabash combined cyclone and gas filtration slipstream test program was developed to provide design information, equipment specification and process control parameters of a hybrid cyclone and candle filter particulate removal system in the E-Gas (TM) gasification process that would provide the optimum performance and reliability for future commercial use. The test program objectives were as follows: 1. Evaluate the use of various cyclone materials of construction; 2. Establish the optimal cyclone efficiency that provides stable long term gas filter operation; 3. Determine the particle size distribution of the char separated by both the cyclone and candle filters. This will provide insight into cyclone efficiency and potential future plant design; 4. Determine the optimum filter media size requirements for the cyclone-filtration hybrid unit; 5. Determine the appropriate char transfer rates for both the cyclone and filtration portions of the hybrid unit; 6. Develop operating procedures for the cyclone-filtration hybrid unit; and, 7. Compare the installed capital cost of a scaled-up commercial cyclone-filtration hybrid unit to the current gas filtration design without a cyclone unit, such as currently exists at the Wabash facility.« less

A Simple Method to Detect Recovery of Glomerular Filtration Rate following Acute Kidney Injury

PubMed Central

Pickering, John W.

2014-01-01

In acute kidney injury (AKI), elevated plasma creatinine is diagnostic of an earlier loss of glomerular filtration rate (GFR) but not of the concomitant GFR. Only subsequent creatinine changes will inform if GFR had already recovered or not. We hypothesized that the creatinine excretion rate to production rate ratio would provide this information. A retrospective analysis of 482 critically ill patients from two intensive care units (ICU) is shown. Plasma creatinine was measured on ICU entry and 12 hours later. Four-hour creatinine excretion rates (E) were measured on entry. Creatinine production rates were estimated (eG). The ability of the ratio E/eG to predict a decrease in plasma creatinine concentration, identify recovered AKI (≥0.3 mg/dL decrease), and predict AKI (≥0.3 mg/dL increase) was assessed by the area under the receiver operator characteristic curves (AUC). There was a linear relationship between reduced creatinine concentration and E/eG (r 2 = 0.15; P < 0.0001). E/eG predicted a decrease in creatinine (AUC 0.70 (0.65 to 0.74)), identified recovered AKI (0.75 (0.67 to 0.84)), and predicted AKI (0.80 (0.73 to 0.86)). A ratio of the rates of creatinine excretion to estimated production much less than 1 indicated a concomitant GFR below baseline, whereas a ratio much more than 1 indicated a recovering or recovered GFR. PMID:24982893

Seasonal variations on the residence times and partitioning of short-lived radionuclides (234Th, 7Be and 210Pb) and depositional fluxes of 7Be and 210Pb in Tampa Bay, Florida

USGS Publications Warehouse

Baskaran, M.; Swarzenski, P.W.

2007-01-01

Historically, Tampa Bay has been impacted heavily by a wide range of anthropogenic perturbations that may include, agricultural-, shipping-, phosphate mining/distribution-related activities, as well as a burgeoning coastal population. Due to the presence of U-rich underlying sediments, elevated activities of U- and Th-series daughter products may be naturally released into this system. This region is also known for summer thunderstorms and corresponding increases in precipitation and surface water runoff. Only limited work has been conducted on the partitioning of particle-reactive radionuclides (such as 7Be, 210Pb, and 234Th) in such a dynamic coastal system. We investigated both the removal residence time and partitioning of these radionuclides between filter-retained particulate matter (≥ 0.5 μm) and the filtrate ( Our results indicate that the partitioning of 7Be, 210Pb, and 234Th between filtrate and filter-retained phase is controlled foremost by enhanced bottom resuspension events during summer thunderstorms. As a consequence, no significant relationship exists between the distribution coefficients (Kd values) of these isotopes and the concentration of suspended particulate matter (SPM). Relatively faster recycling rates of atmospheric water vapor derived from the ocean results in lower atmospheric depositional fluxes of 210Pb to the study site than predicted. The relationship between 7Be and 210Pb in bulk (wet + dry) deposition is compared to their respective water column activities. The residence times of particulate and dissolved 234Th, 7Be and 210Pb, as well the distribution coefficients of these radionuclides, are then compared to values reported in other coastal systems.

Coupling fine particle and bedload transport in gravel-bedded streams

NASA Astrophysics Data System (ADS)

Park, Jungsu; Hunt, James R.

2017-09-01

Fine particles in the silt- and clay-size range are important determinants of surface water quality. Since fine particle loading rates are not unique functions of stream discharge this limits the utility of the available models for water quality assessment. Data from 38 minimally developed watersheds within the United States Geological Survey stream gauging network in California, USA reveal three lines of evidence that fine particle release is coupled with bedload transport. First, there is a transition in fine particle loading rate as a function of discharge for gravel-bedded sediments that does not appear when the sediment bed is composed of sand, cobbles, boulders, or bedrock. Second, the discharge at the transition in the loading rate is correlated with the initiation of gravel mobilization. Third, high frequency particle concentration and discharge data are dominated by clockwise hysteresis where rising limb discharges generally have higher concentrations than falling limb discharges. These three observations across multiple watersheds lead to a conceptual model that fine particles accumulate within the sediment bed at discharges less than the transition and then the gravel bed fluidizes with fine particle release at discharges above the transition discharge. While these observations were individually recognized in the literature, this analysis provides a consistent conceptual model based on the coupling of fine particle dynamics with filtration at low discharges and gravel bed fluidization at higher discharges.

A meta-analysis on diagnostic value of serum cystatin C and creatinine for the evaluation of glomerular filtration function in renal transplant patients.

PubMed

Pan, Pan; Binjie, Hu; Min, Li; Lipei, Fan; Yanli, Ni; Junwen, Zhou; Xianghua, Shi

2014-12-01

This meta-analysis aimed to perform a systematic review on comparing the diagnostic value of serum cystatin C and creatinine for glomerular filtration rate in renal transplant patients. The data was extracted into 2×2 table after the articles were assessed by the tool of QUADAS and heterogeneity analysis. The SROC curve and meta-analysis were performed by MetaDisc1.4. Meta-analysis showed that the serum cystatin C had no heterogeneity (P=0.418, I2=2.2%, DOR=25.03), while creatinine heterogeneity was high (P=0.109, I2=37.5%, DOR=9.11). The values of SEN, SPE and SAUC were calculated as 0.86, 0.70 and 0.9015 for cystatin C, and 0.78, 0.73 and 0.8285 for creatinine individually. This study utilized GFR detection and subgroups analysis by cutoff. The PLR was 6.13 and the NLR was 0.12 for cystatin C, compared to SCr (3.72, 0.32). There was homogeneity among these studies using PENIA testing for cystatin C (χ2=2.61, P=0.4560, I2=0.0%. There were significant correlations among cystatin C , creatinine and glomerular filtration rate (GFR). Cystatin C had more sensitivity but less specificity than creatinine for evaluation of GFR. Cystatin C had strong ability in diagnosing renal function after renal transplant and ruling out diagnostic efficacy.

Aldosterone and glomerular filtration--observations in the general population.

PubMed

Hannemann, Anke; Rettig, Rainer; Dittmann, Kathleen; Völzke, Henry; Endlich, Karlhans; Nauck, Matthias; Wallaschofski, Henri

2014-03-10

Increasing evidence suggests that aldosterone promotes renal damage. Since data on the association between aldosterone and renal function in the general population are sparse, we chose to address this issue. We investigated the associations between the plasma aldosterone concentration (PAC) or the aldosterone-to-renin ratio (ARR) and the estimated glomerular filtration rate (eGFR) in a sample of adult men and women from Northeast Germany. A study population of 1921 adult men and women who participated in the first follow-up of the Study of Health in Pomerania was selected. None of the subjects used drugs that alter PAC or ARR. The eGFR was calculated according to the four-variable Modification of Diet in Renal Disease formula. Chronic kidney disease (CKD) was defined as an eGFR < 60 ml/min/1.73 m2. Linear regression models, adjusted for sex, age, waist circumference, diabetes mellitus, smoking status, systolic and diastolic blood pressures, serum triglyceride concentrations and time of blood sampling revealed inverse associations of PAC or ARR with eGFR (ß-coefficient for log-transformed PAC -3.12, p < 0.001; ß-coefficient for log-transformed ARR -3.36, p < 0.001). Logistic regression models revealed increased odds for CKD with increasing PAC (odds ratio for a one standard deviation increase in PAC: 1.35, 95% confidence interval: 1.06-1.71). There was no statistically significant association between ARR and CKD. Our study demonstrates that PAC and ARR are inversely associated with the glomerular filtration rate in the general population.

Kinetic Glomerular Filtration Rate Equation Can Accommodate a Changing Body Volume: Derivation and Usage of the Formula.

PubMed

Chen, Sheldon

2018-05-22

Ascertaining a patient's kidney function is more difficult to do when the serum creatinine is changing than when it is stable. To accomplish the task, various kinetic clearance equations have been developed. To date, however, none of them have allowed for ongoing changes to the creatinine's volume of distribution. These diluting or concentrating effects on the [creatinine] can greatly impact the accuracy of kidney function assessment. Described herein is a model of creatinine kinetics that also accommodates volume changes. The differential equation is solved for the kinetic glomerular filtration rate (GFR), which is helpful information to the physician. Some of the equation's discontinuities, such as from dividing by a volume rate of zero, can be resolved by using limits. Being "volume-capable," the new kinetic equation reveals how a changing volume influences the maximum rate of rise in [creatinine], a parameter that heretofore was chosen empirically. To show the advantages of incorporating volume, the new and old kinetic equations are applied to a clinical case of overzealous fluid resuscitation. Appropriately, when the volume gain's dilution of [creatinine] is taken into account, the creatinine clearance is calculated to be substantially lower. In conclusion, the kinetic GFR equation has been upgraded to handle volume changes simultaneously with [creatinine] changes. Copyright © 2018. Published by Elsevier Inc.

Angiotensin II Type 1 Receptor Antagonism Attenuates Abnormalities in Dynamic Renal Blood Flow Autoregulation in Rats with Endotoxin-Induced Acute Kidney Injury.

PubMed

Nitescu, Nicoletta; DiBona, Gerald F; Grimberg, Elisabeth; Guron, Gregor

2010-01-01

The aim was to examine the role of angiotensin II type 1 receptors in dynamic autoregulation of renal blood flow (RBF) in endotoxemia. Experiments were performed on anesthetized rats 16 h after intraperitoneal lipopolysaccharide (LPS) or vehicle administration. After baseline measurements, groups Sham-Saline, LPS-Saline and LPS-Candesartan received isotonic saline or candesartan (10 μg kg(-1) i.v.). Data were collected during eight consecutive 20-min clearance periods (C1-8). Transfer function (TF) analysis in the frequency domain was used to examine dynamic autoregulation of RBF. Endotoxemic rats showed an approximate 50% reduction in glomerular filtration rate (GFR) and RBF (p < 0.05 vs. Sham-Saline). Candesartan significantly increased RBF (+40 ± 6% vs. baseline; p < 0.05) but did not significantly influence GFR. Endotoxemic animals showed a normal myogenic response but had elevated TF gain values in the frequency range of the tubuloglomerular feedback mechanism (TGF; 0.01-0.03 Hz) reflecting impaired autoregulation (periods C3-4, 2.2 ± 1.6 vs. -2.6 ± 0.6 dB, p < 0.05, and C7-8, -0.4 ± 1.3 vs. -4.0 ± 0.8 dB, p < 0.05; in groups LPS-Saline and Sham-Saline, respectively). Candesartan normalized TF gain in this frequency range (periods C7-8, -6.1 ± 2.3 dB in group LPS-Candesartan, p < 0.05 vs. LPS-Saline). Candesartan ameliorates the adverse effect of endotoxin on the TGF component of dynamic autoregulation of RBF. Copyright © 2010 S. Karger AG, Basel.

Method for reducing pressure drop through filters, and filter exhibiting reduced pressure drop

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sappok, Alexander; Wong, Victor

Methods for generating and applying coatings to filters with porous material in order to reduce large pressure drop increases as material accumulates in a filter, as well as the filter exhibiting reduced and/or more uniform pressure drop. The filter can be a diesel particulate trap for removing particulate matter such as soot from the exhaust of a diesel engine. Porous material such as ash is loaded on the surface of the substrate or filter walls, such as by coating, depositing, distributing or layering the porous material along the channel walls of the filter in an amount effective for minimizing ormore » preventing depth filtration during use of the filter. Efficient filtration at acceptable flow rates is achieved.« less

42 CFR 410.130 - Definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

... transplantation (glomerular filtration rate [GFR] 13-50 ml/min/1.73m2). Diabetes means diabetes mellitus, a... person with symptoms of uncontrolled diabetes. Episode of care means services covered in a 12-month time period when coordinated with initial diabetes self-management training (DSMT) and one calendar year for...

The drinking water treatment process as a potential source of affecting the bacterial antibiotic resistance.

PubMed

Bai, Xiaohui; Ma, Xiaolin; Xu, Fengming; Li, Jing; Zhang, Hang; Xiao, Xiang

2015-11-15

Two waterworks, with source water derived from the Huangpu or Yangtze River in Shanghai, were investigated, and the effluents were plate-screened for antibiotic-resistant bacteria (ARB) using five antibiotics: ampicillin (AMP), kanamycin (KAN), rifampicin (RFP), chloramphenicol (CM) and streptomycin (STR). The influence of water treatment procedures on the bacterial antibiotic resistance rate and the changes that bacteria underwent when exposed to the five antibiotics at concentration levels ranging from 1 to 100 μg/mL were studied. Multi-drug resistance was also analyzed using drug sensitivity tests. The results indicated that bacteria derived from water treatment plant effluent that used the Huangpu River rather than the Yangtze River as source water exhibited higher antibiotic resistance rates against AMP, STR, RFP and CM but lower antibiotic resistance rates against KAN. When the antibiotic concentration levels ranged from 1 to 10 μg/mL, the antibiotic resistance rates of the bacteria in the water increased as water treatment progressed. Biological activated carbon (BAC) filtration played a key role in increasing the antibiotic resistance rate of bacteria. Chloramine disinfection can enhance antibiotic resistance. Among the isolated ARB, 75% were resistant to multiple antibiotics. Ozone oxidation, BAC filtration and chloramine disinfection can greatly affect the relative abundance of bacteria in the community. Copyright © 2015 Elsevier B.V. All rights reserved.

Application of Sodium Ligno Sulphonate as Surfactant in Enhanced Oil Recovery and Its Feasibility Test for TPN 008 Oil

NASA Astrophysics Data System (ADS)

Prakoso, N. I.; Rochmadi; Purwono, S.

2018-04-01

One of enhanced oil recovery (EOR) methods is using surfactants to reduce the interfacial tension between the injected fluid and the oil in old reservoir. The most important principle in enhanced oil recovery process is the dynamic interaction of surfactants with crude oil. Sodium ligno sulphonate (SLS) is a commercial surfactant and already synthesized from palm solid waste by another researcher. This work aimed to apply SLS as a surfactant for EOR especially in TPN 008 oil from Pertamina Indonesia. In its application as an EOR’s surfactant, SLS shall be passed feasibility test like IFT, thermal stability, compatibility, filtration, molecular weight, density, viscosity and pH tests. The feasibility test is very important for a preliminary test prior to another advanced test. The results demonstrated that 1% SLS solution in formation water (TPN 008) had 0.254 mN/M IFT value and was also great in thermal stability, compatibility, filtration, molecular weight, viscosity and pH test.

Regenerative Aerobraking

NASA Technical Reports Server (NTRS)

Moses, Robert W.

2004-01-01

NASA's exploration goals for Mars and Beyond will require new power systems and in situ resource utilization technologies. Regenerative aerobraking may offer a revolutionary approach for in situ power generation and oxygen harvesting during these exploration missions. In theory, power and oxygen can be collected during aerobraking and stored for later use in orbit or on the planet. This technology would capture energy and oxygen from the plasma field that occurs naturally during hypersonic entry using well understood principles of magnetohydrodynamics and oxygen filtration. This innovative approach generates resources upon arrival at the operational site, and thus greatly differs from the traditional approach of taking everything you need with you from Earth. Fundamental analysis, computational fluid dynamics, and some testing of experimental hardware have established the basic feasibility of generating power during a Mars entry. Oxygen filtration at conditions consistent with spacecraft entry parameters at Mars has been studied to a lesser extent. Other uses of the MHD power are presented. This paper illustrates how some features of regenerative aerobraking may be applied to support human and robotic missions at Mars.

Rotary filtration system

DOEpatents

Herman, David T [Aiken, SC; Maxwell, David N [Aiken, SC

2011-04-19

A rotary filtration apparatus for filtering a feed fluid into permeate is provided. The rotary filtration apparatus includes a container that has a feed fluid inlet. A shaft is at least partially disposed in the container and has a passageway for the transport of permeate. A disk stack made of a plurality of filtration disks is mounted onto the shaft so that rotation of the shaft causes rotation of the filtration disks. The filtration disks may be made of steel components and may be welded together. The shaft may penetrate a filtering section of the container at a single location. The rotary filtration apparatus may also incorporate a bellows seal to prevent leakage along the shaft, and an around the shaft union rotary joint to allow for removal of permeate. Various components of the rotary filtration apparatus may be removed as a single assembly.

Uptake of wheel-filtration among clients of a supervised injecting facility: Can structured education work?

PubMed

Steele, Maureen; Silins, Edmund; Flaherty, Ian; Hiley, Sarah; van Breda, Nick; Jauncey, Marianne

2018-01-01

Wheel-filtration of pharmaceutical opioid tablets is a recognised harm reduction strategy, but uptake of the practice among people who inject drugs is low. The study aimed to: (i) examine perceptions of filtration practices; (ii) provide structured education on wheel-filtration; and (iii) assess uptake of the practice. Frequent opioid tablet injectors (n = 30) attending a supervised injecting facility in Sydney, Australia, received hands-on instruction on wheel-filtration based on recommended practice. Pre-education, post-education and follow-up questionnaires were administered. Wheel-filtration was generally regarded as better than cotton-filtration (the typical method) in terms of perceived effects on health, ease of use and overall drug effect. Sixty-eight percent of those who said they would try wheel-filtration after the education had actually done so. Of those who usually used cotton-filtration, over half (60%) had used wheel-filtration two weeks later. Uptake of safer preparation methods for pharmaceutical opioid tablets increases after structured education in wheel-filtration. Findings suggest that SIFs are an effective site for this kind of education. Supervised injecting facility workers are uniquely positioned to provide harm reduction education at the time of injection. [Steele M, Silins E, Flaherty I, Hiley S, van Breda N, Jauncey M. Uptake of wheel-filtration among clients of a supervised injecting facility: Can structured education work? Drug Alcohol Rev 2018;37:116-120]. © 2017 Australasian Professional Society on Alcohol and other Drugs.

Measurement of glomerular filtration rate, renal plasma flow, and endogenous creatinine clearance in cheetahs (Acinonyx jubatus jubatus).

PubMed

Holder, Erin Hall; Citino, Scott B; Businga, Nancy; Cartier, Leslie; Brown, Scott A

2004-06-01

Glomerular filtration rate (GFR), renal plasma flow (RPF), and the endogenous creatinine clearance (CCr) rate were determined in 13 captive cheetahs, Acinonyx jubatus jubatus (seven females and six males, 1.5-7.5 yr of age, x = 5.02 yr), during general anesthesia with Telazol and isoflurane by measuring the urinary clearances of inulin, para-aminohipppuric acid, and endogenous creatinine, respectively. Methods to determine GFR, RPF, and endogenous CCr in captive cheetahs were evaluated, and the relationship between GFR and CCr for this species was determined. The GFR and the RPF were stable during the procedure, with mean values of 1.59+/-0.17 ml/min/kg body weight and 5.12+/-1.15 ml/min/kg body weight, respectively. Although the mean value for CCr (1.47+/-0.20 ml/min/kg body weight) was significantly less than the corresponding value for GFR, the mean difference (0.11+/-0.02 ml/min/kg weight) between the two measurements was slight, and the values were highly correlated (R2 = 0.928; P < 0.0001). The measurement of CCr in cheetahs should provide a reliable estimate of GFR, facilitating the early detection of renal disease in this species.

Multi-walled carbon nanotubes with selected properties for dynamic filtration of pharmaceuticals and personal care products.

PubMed

Wang, Yifei; Ma, Jing; Zhu, Jiaxin; Ye, Ning; Zhang, Xiaolei; Huang, Haiou

2016-04-01

In this study, multi-walled carbon nanotubes (MWCNT) with selected properties, including pristine MWCNT, hydroxylated MWCNT (H-MWCNT), thin-walled MWCNT with large inner diameter (L-MWCNT), aminated MWCNT, and high-purity MWCNT were investigated for dynamic removal of eight pharmaceuticals and personal care products (PPCP). The removal ratios of different PPCP by the pristine MWCNT followed a decreasing order of triclosan (0.93) > prometryn (0.71) > 4-acetylamino-antipyrine (0.67) > carbendazim (0.65) > caffeine (0.42) > ibuprofen (0.34) > acetaminophen (0.29) at 100 min of filtration. Similar or even higher PPCP removals were obtained for all PPCP as the influent concentration decreased, suggesting potential consistent PPCP removals at environmental PPCP concentrations. The removal ratio of acetaminophen was increased to 0.74 by using H-MWCNT. SRFA (Suwannee River fulvic acid) suppressed PPCP adsorption to MWCNT, to greater extents with increasing SRFA concentrations. The L-MWCNT, despite a large inner diameter of 52 ± 3 nm, did not provide better resistance to the competitive adsorption of SRFA than MWCNT with a small inner diameter of 10 ± 2 nm. Future research will be conducted to minimize the effect of SRFA and facilitate application of MWCNT to the treatment of PPCP-contaminated water. Copyright © 2016 Elsevier Ltd. All rights reserved.

Four years experience with filtration systems in commercial nurseries for eliminating Phytophthora species from recirculation water

Treesearch

T. Ufer; M. Posner; H.-P. Wessels; S. Wagner; K. Kaminski; T. Brand; Werres S.

2008-01-01

In a four year project, three different filtration systems were tested under commercial nursery conditions to eliminate Phytophthora spp. from irrigation water. Five nurseries were involved in the project. Slow sand filtration systems were tested in three nurseries. In the fourth nursery, a filtration system with lava grains (Shieer® Bio filtration)...

Evaluation of automatic dose rate control for flat panel imaging using a spatial frequency domain figure of merit.

PubMed

Dehairs, M; Bosmans, H; Desmet, W; Marshall, N W

2017-07-31

Current automatic dose rate controls (ADRCs) of dynamic x-ray imaging systems adjust their acquisition parameters in response to changes in patient thickness in order to achieve a constant signal level in the image receptor. This work compares a 3 parameter (3P) ADRC control to a more flexible 5-parameter (5P) method to meet this goal. A phantom composed of 15 composite poly(methyl) methacrylate (PMMA)/aluminium (Al) plates was imaged on a Siemens Artis Q dynamic system using standard 3P and 5P ADRC techniques. Phantom thickness covered a water equivalent thickness (WET) range of 2.5 cm to 37.5 cm. Acquisition parameter settings (tube potential, tube current, pulse length, copper filtration and focus size) and phantom entrance air kerma rate (EAKR) were recorded as the thickness changed. Signal difference to noise ratio (SDNR) was measured using a 0.3 mm iron insert centred in the PMMA stack, positioned at the system isocentre. SDNR was then multiplied by modulation transfer function (MTF) based correction factors for focal spot penumbral blurring and motion blurring, to give a spatial frequency dependent parameter, SDNR(u). These MTF correction factors were evaluated for an object motion of 25 mm s -1 and at a spatial frequency of 1.4 mm -1 in the object plane, typical for cardiac imaging. The figure of merit (FOM) was calculated as SDNR(u)²/EAKR for the two ADRC regimes. Using 5P versus 3P technique showed clear improvements over all thicknesses. Averaged over clinically relevant adult WET values (20 cm-37.5 cm), EAKR was reduced by 13% and 27% for fluoroscopy and acquisition modes, respectively, while the SDNR(u) based FOM increased by 16% and 34% for fluoroscopy and acquisition. In conclusion, the generalized FOM, taking into account the influence of focus size and object motion, showed benefit in terms of image quality and patient dose for the 5-parameter control over 3-parameter method for the ADRC programming of dynamic x-ray imaging systems.

Evaluation of automatic dose rate control for flat panel imaging using a spatial frequency domain figure of merit

NASA Astrophysics Data System (ADS)

Dehairs, M.; Bosmans, H.; Desmet, W.; Marshall, N. W.

2017-08-01

Current automatic dose rate controls (ADRCs) of dynamic x-ray imaging systems adjust their acquisition parameters in response to changes in patient thickness in order to achieve a constant signal level in the image receptor. This work compares a 3 parameter (3P) ADRC control to a more flexible 5-parameter (5P) method to meet this goal. A phantom composed of 15 composite poly(methyl) methacrylate (PMMA)/aluminium (Al) plates was imaged on a Siemens Artis Q dynamic system using standard 3P and 5P ADRC techniques. Phantom thickness covered a water equivalent thickness (WET) range of 2.5 cm to 37.5 cm. Acquisition parameter settings (tube potential, tube current, pulse length, copper filtration and focus size) and phantom entrance air kerma rate (EAKR) were recorded as the thickness changed. Signal difference to noise ratio (SDNR) was measured using a 0.3 mm iron insert centred in the PMMA stack, positioned at the system isocentre. SDNR was then multiplied by modulation transfer function (MTF) based correction factors for focal spot penumbral blurring and motion blurring, to give a spatial frequency dependent parameter, SDNR(u). These MTF correction factors were evaluated for an object motion of 25 mm s-1 and at a spatial frequency of 1.4 mm-1 in the object plane, typical for cardiac imaging. The figure of merit (FOM) was calculated as SDNR(u)²/EAKR for the two ADRC regimes. Using 5P versus 3P technique showed clear improvements over all thicknesses. Averaged over clinically relevant adult WET values (20 cm-37.5 cm), EAKR was reduced by 13% and 27% for fluoroscopy and acquisition modes, respectively, while the SDNR(u) based FOM increased by 16% and 34% for fluoroscopy and acquisition. In conclusion, the generalized FOM, taking into account the influence of focus size and object motion, showed benefit in terms of image quality and patient dose for the 5-parameter control over 3-parameter method for the ADRC programming of dynamic x-ray imaging systems.

Optimized filtration for reduced defectivity and improved dispense recipe in 193-nm BARC lithography

NASA Astrophysics Data System (ADS)

Do, Phong; Pender, Joe; Lehmann, Thomas; Mc Ardle, Leo P.; Gotlinsky, Barry; Mesawich, Michael

2004-05-01

The implementation of 193 nm lithography into production has been complicated by high defectivity issues. Many companies have been struggling with high defect densities, forcing process and lithography engineers to focus their efforts on chemical filtration instead of process development. After-etch defects have complicated the effort to reduce this problem. In particular it has been determined that chemical filtration at the 90 nm node and below is a crucial item which current industry standard pump recipes and material choices are not able to address. LSI Logic and Pall Corporation have been working together exploring alternative materials and resist pump process parameters to address these issues. These changes will free up process development time by reducing these high defect density issues. This paper provides a fundamental understanding of how 20nm filtration combined with optimized resist pump set-up and dispense can significantly reduce defects in 193nm lithography. The purpose of this study is to examine the effectiveness of 20 nanometer rated filters to reduce various defects observed in bottom anti reflective coating materials. Multiple filter types were installed on a Tokyo Electron Limited Clean Track ACT8 tool utilizing two-stage resist pumps. Lithographic performance of the filtered resist and defect analysis of patterned and non-patterned wafers were performed. Optimized pump start-up and dispense recipes also were evaluated to determine their effect on defect improvements. The track system used in this experiment was a standard production tool and was not modified from its original specifications.

Decolorization of complex dyes and textile effluent by extracellular enzymes of Cyathus bulleri cultivated on agro-residues/domestic wastes and proposed pathway of degradation of Kiton blue A and reactive orange 16.

PubMed

Vats, Arpita; Mishra, Saroj

2017-04-01

In this study, the white-rot fungus Cyathus bulleri was cultivated on low-cost agro-residues, namely wheat bran (WB), wheat straw (WS), and domestic waste orange peel (OP) for production of ligninolytic enzymes. Of the three substrates, WB and OP served as good materials for the production of laccase with no requirement of additional carbon or nitrogen source. Specific laccase activity of 94.4 U mg -1 extracellular protein and 21.01 U mg -1 protein was obtained on WB and OP, respectively. Maximum decolorization rate of 13.6 μmol h -1  U -1 laccase for reactive black 5 and 22.68 μmol h -1  U -1 laccase for reactive orange 16 (RO) was obtained with the WB culture filtrate, and 11.7 μmol h -1  U -1 laccase for reactive violet 5 was observed with OP culture filtrate. Importantly, Kiton blue A (KB), reported not to be amenable to enzymatic degradation, was degraded by culture filtrate borne activities. Products of degradation of KB and RO were identified by mass spectrometry, and a pathway of degradation proposed. WB-grown culture filtrate decolorized and detoxified real and simulated textile effluents by about 40%. The study highlights the use of inexpensive materials for the production of enzymes effective on dyes and effluents.

Fast Filtration of Bacterial or Mammalian Suspension Cell Cultures for Optimal Metabolomics Results

PubMed Central

Bordag, Natalie; Janakiraman, Vijay; Nachtigall, Jonny; González Maldonado, Sandra; Bethan, Bianca; Laine, Jean-Philippe; Fux, Elie

2016-01-01

The metabolome offers real time detection of the adaptive, multi-parametric response of the organisms to environmental changes, pathophysiological stimuli or genetic modifications and thus rationalizes the optimization of cell cultures in bioprocessing. In bioprocessing the measurement of physiological intracellular metabolite levels is imperative for successful applications. However, a sampling method applicable to all cell types with little to no validation effort which simultaneously offers high recovery rates, high metabolite coverage and sufficient removal of extracellular contaminations is still missing. Here, quenching, centrifugation and fast filtration were compared and fast filtration in combination with a stabilizing washing solution was identified as the most promising sampling method. Different influencing factors such as filter type, vacuum pressure, washing solutions were comprehensively tested. The improved fast filtration method (MxP® FastQuench) followed by routine lipid/polar extraction delivers a broad metabolite coverage and recovery reflecting well physiological intracellular metabolite levels for different cell types, such as bacteria (Escherichia coli) as well as mammalian cells chinese hamster ovary (CHO) and mouse myeloma cells (NS0).The proposed MxP® FastQuench allows sampling, i.e. separation of cells from medium with washing and quenching, in less than 30 seconds and is robustly designed to be applicable to all cell types. The washing solution contains the carbon source respectively the 13C-labeled carbon source to avoid nutritional stress during sampling. This method is also compatible with automation which would further reduce sampling times and the variability of metabolite profiling data. PMID:27438065

Technical Note: On maximizing Cherenkov emissions from medical linear accelerators.

PubMed

Shrock, Zachary; Yoon, Suk W; Gunasingha, Rathnayaka; Oldham, Mark; Adamson, Justus

2018-04-19

Cherenkov light during MV radiotherapy has recently found imaging and therapeutic applications but is challenged by relatively low fluence. Our purpose is to investigate the feasibility of increasing Cherenkov light production during MV radiotherapy by increasing photon energy and applying specialized beam-hardening filtration. GAMOS 5.0.0, a GEANT4-based framework for Monte Carlo simulations, was used to model standard clinical linear accelerator primary photon beams. The photon source was incident upon a 17.8 cm 3 cubic water phantom with a 94 cm source to surface distance. Dose and Cherenkov production was determined at depths of 3-9 cm. Filtration was simulated 15 cm below the photon beam source. Filter materials included aluminum, iron, and copper with thicknesses of 2-20 cm. Histories used depended on the level of attenuation from the filter, ranging from 100 million to 2 billion. Comparing average dose per history also allowed for evaluation of dose-rate reduction for different filters. Overall, increasing photon beam energy is more effective at improving Cherenkov production per unit dose than is filtration, with a standard 18 MV beam yielding 3.3-4.0× more photons than 6 MV. Introducing an aluminum filter into an unfiltered 2400 cGy/min 10 MV beam increases the Cherenkov production by 1.6-1.7×, while maintaining a clinical dose rate of 300 cGy/min, compared to increases of ~1.5× for iron and copper. Aluminum was also more effective than the standard flattening filter, with the increase over the unfiltered beam being 1.4-1.5× (maintaining 600 cGy/min dose rate) vs 1.3-1.4× for the standard flattening filter. Applying a 10 cm aluminum filter to a standard 18 MV, photon beam increased the Cherenkov production per unit dose to 3.9-4.3× beyond that of 6 MV (vs 3.3-4.0× for 18 MV with no aluminum filter). Through a combination of increasing photon energy and applying specialized beam-hardening filtration, the amount of Cherenkov photons per unit radiotherapy dose can be increased substantially. © 2018 American Association of Physicists in Medicine.

Industrial Application of Open Pore Ceramic Foam for Molten Metal Filtration

NASA Astrophysics Data System (ADS)

Gauckler, L. J.; Waeber, M. M.; Conti, C.; Jacob-Dulière, M.

Ceramic foam filters were used for industrial filtration of aluminum. Results are compared with laboratory experiments which are in good agreement with trajectory analyses of deep bed filtration for the early stage of filtration.

40 CFR 141.719 - Additional filtration toolbox components.

Code of Federal Regulations, 2011 CFR

2011-07-01

... establish a quality control release value (QCRV) for a non-destructive performance test that demonstrates... Detection Limit) (5) Challenge testing must be conducted at the maximum design flow rate for the filter as... representative hydraulic conditions at the maximum design flux and maximum design process recovery specified by...

40 CFR 141.719 - Additional filtration toolbox components.

Code of Federal Regulations, 2010 CFR

2010-07-01

... establish a quality control release value (QCRV) for a non-destructive performance test that demonstrates... Detection Limit) (5) Challenge testing must be conducted at the maximum design flow rate for the filter as... representative hydraulic conditions at the maximum design flux and maximum design process recovery specified by...

Influence of kidney function on risk of supratherapeutic international normalized ratio-related hemorrhage in warfarin users: a prospective cohort study

USDA-ARS?s Scientific Manuscript database

Background: Anticoagulation management is difficult in chronic kidney disease, with frequent supratherapeutic international normalized ratios (INRs >/= 4) increasing hemorrhagic risk. We evaluated whether the interaction of INR and lower estimated glomerular filtration rate (eGFR) increases hemorrha...

The Renal Renin-Angiotensin System

ERIC Educational Resources Information Center

Harrison-Bernard, Lisa M.

2009-01-01

The renin-angiotensin system (RAS) is a critical regulator of sodium balance, extracellular fluid volume, vascular resistance, and, ultimately, arterial blood pressure. In the kidney, angiotensin II exerts its effects to conserve salt and water through a combination of the hemodynamic control of renal blood flow and glomerular filtration rate and…

Lifestyle factors and indices of kidney function in the Framingham Heart Study

USDA-ARS?s Scientific Manuscript database

Background and objectives: Lifestyle characteristics are modifiable factors that could be targeted as part of chronic kidney disease (CKD) prevention. We sought to determine the association of lifestyle characteristics with incident estimated glomerular filtration rate (eGFR)<60mL/min/1.73m2 and rap...

Oily Waste Water Treatment System

DTIC Science & Technology

1998-01-22

from three 6 series connected, ceramic membrane type of filtration units 82, 84 and 86 through a conduit 80. 7 The flow rate and pressure of the...hereinbefore described is of the silica-coated 4 P- ceramic membrane type through which effluent from the oil/water separator 20 may be processed

Removal of pathogens using riverbank filtration

NASA Astrophysics Data System (ADS)

Cote, M. M.; Emelko, M. B.; Thomson, N. R.

2003-04-01

Although more than hundred years old, in situ or Riverbank Filtration (RBF) has undergone a renewed interest in North America because of its potential as a surface water pre-treatment tool for removal of pathogenic microorganisms. A new RBF research field site has been constructed along the banks of the Grand River in Kitchener, Ontario, Canada to assess factors influencing pathogen removal in the subsurface. Implementation of RBF and appropriate design of subsequent treatment (UV, chlorination, etc.) processes requires successful quantification of in situ removals of Cryptosporidium parvum or a reliable surrogate parameter. C.~parvum is often present in surface water at low indigenous concentrations and can be difficult to detect in well effluents. Since releases of inactivated C.~parvum at concentrations high enough for detection in well effluents are cost prohibitive, other approaches for demonstrating effective in situ filtration of C.~parvum must be considered; these include the use of other microbial species or microspheres as indicators of C.~parvum transport in the environment. Spores of Bacillus subtilis may be considered reasonable indicators of C.~parvum removal by in situ filtration because of their size (˜1 μm in diameter), spherical shape, relatively high indigenous concentration is many surface waters, and relative ease of enumeration. Based on conventional particle filtration theory and assuming equivalent chemical interactions for all particle sizes, a 1 μm B.~subtilis spore will be removed less readily than a larger C. parvum oocyst (4-6 μm) in an ideal granular filter. Preliminary full-scale data obtained from a high rate RBF production well near the new RBF test site demonstrated greater than 1 log removal of B.~subtilis spores. This observed spore removal is higher than that prescribed by the proposed U.S. Long Term 2 Enhanced Surface Water Treatment Rule for C.~parvum. To further investigate the removal relationship between C.~parvum, Giardia lamblia and proposed surrogates such as B.~subtilis, detailed characterization of site hydrogeology, geochemistry, and water quality (MPA, particles, TOC, ionic strength) are underway. Particle counts are being measured in the bank filtrate to compare particle breakthrough with breakthrough of B.~subtilis spores. Particle counting has been suggested by some regulatory bodies as a real-time measure of in situ filtration performance; however, particle counting is a limited tool for assessing the efficacy of pathogen removal by in situ filtration because it is incapable of identifying discrete particles and can fail to detect microorganisms with refraction indexes close to that of water. Preliminary B.~subtilis removal data from the full scale RBF well and preliminary site characterization, particle count, and B.~subtilis removal data from the RBF test site are presented.

Water Filtration

ERIC Educational Resources Information Center

Jacobsen, Erica K.

2004-01-01

A water filtration column is devised by students using a two-liter plastic bottle containing gravel, sand, and activated charcoal, to test the filtration potential of the column. Results indicate that the filtration column eliminates many of the contaminating materials, but does not kill bacteria.

10. OBLIQUE DETAIL VIEW OF PUMP NO. 1 IN FILTRATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. OBLIQUE DETAIL VIEW OF PUMP NO. 1 IN FILTRATION ROOM IN FILTRATION PLANT (#1773), LOOKING NORTHEAST - Presidio Water Treatment Plant, Filtration Plant, East of Lobos Creek at Baker Beach, San Francisco, San Francisco County, CA

Operation, Maintenance and Performance Evaluation of the Potomac Estuary Experimental Water Treatment Plant. Executive Summary.

DTIC Science & Technology

1983-09-01

tion of appropriate isotherm and rate model parameters for TOC and one SOC. - Evaluation of GAC design alternatives at different treatment...permits an estimate of corrosion rates , based on weight loss of pipe inserts maintained in continuous contact with the finished water. With respect to the...coagulation, sedimentation, recarbonation, gravity filtration, GAC adsorption at twice the contact time, ozone and chloramine for final disinfection. An

Predicting Renal Failure Progression in Chronic Kidney Disease Using Integrated Intelligent Fuzzy Expert System.

PubMed

Norouzi, Jamshid; Yadollahpour, Ali; Mirbagheri, Seyed Ahmad; Mazdeh, Mitra Mahdavi; Hosseini, Seyed Ahmad

2016-01-01

Chronic kidney disease (CKD) is a covert disease. Accurate prediction of CKD progression over time is necessary for reducing its costs and mortality rates. The present study proposes an adaptive neurofuzzy inference system (ANFIS) for predicting the renal failure timeframe of CKD based on real clinical data. This study used 10-year clinical records of newly diagnosed CKD patients. The threshold value of 15 cc/kg/min/1.73 m(2) of glomerular filtration rate (GFR) was used as the marker of renal failure. A Takagi-Sugeno type ANFIS model was used to predict GFR values. Variables of age, sex, weight, underlying diseases, diastolic blood pressure, creatinine, calcium, phosphorus, uric acid, and GFR were initially selected for the predicting model. Weight, diastolic blood pressure, diabetes mellitus as underlying disease, and current GFR(t) showed significant correlation with GFRs and were selected as the inputs of model. The comparisons of the predicted values with the real data showed that the ANFIS model could accurately estimate GFR variations in all sequential periods (Normalized Mean Absolute Error lower than 5%). Despite the high uncertainties of human body and dynamic nature of CKD progression, our model can accurately predict the GFR variations at long future periods.

AAPM/RSNA physics tutorial for residents: physics of flat-panel fluoroscopy systems: Survey of modern fluoroscopy imaging: flat-panel detectors versus image intensifiers and more.

PubMed

Nickoloff, Edward Lee

2011-01-01

This article reviews the design and operation of both flat-panel detector (FPD) and image intensifier fluoroscopy systems. The different components of each imaging chain and their functions are explained and compared. FPD systems have multiple advantages such as a smaller size, extended dynamic range, no spatial distortion, and greater stability. However, FPD systems typically have the same spatial resolution for all fields of view (FOVs) and are prone to ghosting. Image intensifier systems have better spatial resolution with the use of smaller FOVs (magnification modes) and tend to be less expensive. However, the spatial resolution of image intensifier systems is limited by the television system to which they are coupled. Moreover, image intensifier systems are degraded by glare, vignetting, spatial distortions, and defocusing effects. FPD systems do not have these problems. Some recent innovations to fluoroscopy systems include automated filtration, pulsed fluoroscopy, automatic positioning, dose-area product meters, and improved automatic dose rate control programs. Operator-selectable features may affect both the patient radiation dose and image quality; these selectable features include dose level setting, the FOV employed, fluoroscopic pulse rates, geometric factors, display software settings, and methods to reduce the imaging time. © RSNA, 2011.

Computational Fluid Dynamics Analysis of the Fossil Crinoid Encrinus liliiformis (Echinodermata: Crinoidea)

PubMed Central

Dynowski, Janina F.; Nebelsick, James H.; Klein, Adrian; Roth-Nebelsick, Anita

2016-01-01

Crinoids, members of the phylum Echinodermata, are passive suspension feeders and catch plankton without producing an active feeding current. Today, the stalked forms are known only from deep water habitats, where flow conditions are rather constant and feeding velocities relatively low. For feeding, they form a characteristic parabolic filtration fan with their arms recurved backwards into the current. The fossil record, in contrast, provides a large number of stalked crinoids that lived in shallow water settings, with more rapidly changing flow velocities and directions compared to the deep sea habitat of extant crinoids. In addition, some of the fossil representatives were possibly not as flexible as today’s crinoids and for those forms alternative feeding positions were assumed. One of these fossil crinoids is Encrinus liliiformis, which lived during the middle Triassic Muschelkalk in Central Europe. The presented project investigates different feeding postures using Computational Fluid Dynamics to analyze flow patterns forming around the crown of E. liliiformis, including experimental validation by Particle Image Velocimetry. The study comprises the analysis of different flow directions, velocities, as well as crown orientations. Results show that inflow from lateral and oral leads to direct transport of plankton particles into the crown and onto the oral surface. With current coming from the “rear” (aboral) side of the crinoid, the conical opening of the crown produces a backward oriented flow in its wake that transports particles into the crown. The results suggest that a conical feeding position may have been less dependent on stable flow conditions compared to the parabolic filtration fan. It is thus assumed that the conical feeding posture of E. liliiformis was suitable for feeding under dynamically changing flow conditions typical for the shallow marine setting of the Upper Muschelkalk. PMID:27243221

Nephrin Tyrosine Phosphorylation Is Required to Stabilize and Restore Podocyte Foot Process Architecture

PubMed Central

New, Laura A.; Martin, Claire E.; Scott, Rizaldy P.; Platt, Mathew J.; Keyvani Chahi, Ava; Stringer, Colin D.; Lu, Peihua; Samborska, Bozena; Eremina, Vera; Takano, Tomoko; Simpson, Jeremy A.; Quaggin, Susan E.

2016-01-01

Podocytes are specialized epithelial cells of the kidney blood filtration barrier that contribute to permselectivity via a series of interdigitating actin–rich foot processes. Positioned between adjacent projections is a unique cell junction known as the slit diaphragm, which is physically connected to the actin cytoskeleton via the transmembrane protein nephrin. Evidence indicates that tyrosine phosphorylation of the intracellular tail of nephrin initiates signaling events, including recruitment of cytoplasmic adaptor proteins Nck1 and Nck2 that regulate actin cytoskeletal dynamics. Nephrin tyrosine phosphorylation is altered in human and experimental renal diseases characterized by pathologic foot process remodeling, prompting the hypothesis that phosphonephrin signaling directly influences podocyte morphology. To explore this possibility, we generated and analyzed knockin mice with mutations that disrupt nephrin tyrosine phosphorylation and Nck1/2 binding (nephrinY3F/Y3F mice). Homozygous nephrinY3F/Y3F mice developed progressive proteinuria accompanied by structural changes in the filtration barrier, including podocyte foot process effacement, irregular thickening of the glomerular basement membrane, and dilated capillary loops, with a similar but later onset phenotype in heterozygous animals. Furthermore, compared with wild-type mice, nephrinY3F/Y3F mice displayed delayed recovery in podocyte injury models. Profiling of nephrin tyrosine phosphorylation dynamics in wild-type mice subjected to podocyte injury indicated site-specific differences in phosphorylation at baseline, injury, and recovery, which correlated with loss of nephrin-Nck1/2 association during foot process effacement. Our results define an essential requirement for nephrin tyrosine phosphorylation in stabilizing podocyte morphology and suggest a model in which dynamic changes in phosphotyrosine-based signaling confer plasticity to the podocyte actin cytoskeleton. PMID:26802179

Actin dynamics at focal adhesions: a common endpoint and putative therapeutic target for proteinuric kidney diseases.

PubMed

Sever, Sanja; Schiffer, Mario

2018-06-01

Proteinuria encompasses diverse causes including both genetic diseases and acquired forms such as diabetic and hypertensive nephropathy. The basis of proteinuria is a disturbance in size selectivity of the glomerular filtration barrier, which largely depends on the podocyte: a terminally differentiated epithelial cell type covering the outer surface of the glomerulus. Compromised podocyte structure is one of the earliest signs of glomerular injury. The phenotype of diverse animal models and podocyte cell culture firmly established the essential role of the actin cytoskeleton in maintaining functional podocyte structure. Podocyte foot processes, actin-based membrane extensions, contain 2 molecularly distinct "hubs" that control actin dynamics: a slit diaphragm and focal adhesions. Although loss of foot processes encompasses disassembly of slit diaphragm multiprotein complexes, as long as cells are attached to the glomerular basement membrane, focal adhesions will be the sites in which stress due to filtration flow is counteracted by forces generated by the actin network in foot processes. Numerous studies within last 20 years have identified actin binding and regulatory proteins as well as integrins as essential components of signaling and actin dynamics at focal adhesions in podocytes, suggesting that some of them may become novel, druggable targets for proteinuric kidney diseases. Here we review evidence supporting the idea that current treatments for chronic kidney diseases beneficially and directly target the podocyte actin cytoskeleton associated with focal adhesions and suggest that therapeutic reagents that target the focal adhesion-regulated actin cytoskeleton in foot processes have potential to modernize treatments for chronic kidney diseases. Copyright © 2018 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Feasibility of triphasic CT with a modified two-point Patlak plot to determine spit kidney glomerular filtration rate in clinical practice.

PubMed

Zhang, Yu-Dong; Xue, Chen-Qi; Wu, Chen-Jiang; Tao, Jun; Zhou, Wan-Li; Shi, Hai-Bin

2017-01-01

To investigate whether triphasic CT with a simplified Patlak plot can be used in clinical practice for the estimate of split kidney glomerular filtration rate (SKGFR). The animal experiment included 15 rabbits that underwent 40 dynamic contrast-enhanced CT scans of the kidneys with 1.5 s time interval. Patlak-derived SKGFR was obtained using standard forty-point, two-point (unenhanced phase, arterial phase t α, and portovenous phase t β ), and a modified two-point (MTP) (unenhanced, t α , t β , and a virtual t τ [t τ  = (t α  + t β )/2]) image data, respectively. The MTP-Patlak plot approach was then validated in 13 patients who underwent a triphasic renal contrast-enhanced CT examination. SKGFR measured by 99 m Tc-DTPA clearance was as a standard reference. MTP-Patlak significantly reduced input function errors than two-point Patlak (21.1 ± 16.2 % vs 30.8 ± 15.2 %, p < 0.01) and showed good concordance with standard Patlak for measurement of SKGFR in animal experiment (1.20 ± 0.38 mL/g/min vs 1.51 ± 0.43 mL/g/min; linear correlation coefficient r = 0.87, p < 0.001). Human study showed that mean SKGFR was 45.7 mL/min (range, 26.5-86.2 mL/min) obtained from 99 m Tc-DTPA, and 38.2 mL/min (range, 18.6-79.3 mL/min) obtained from triphasic CT using MTP-Patlak plot. Linear correlation between the two methods was r = 0.75 (p < 0.01). The mean difference between SKGFRs as determined with the two methods was 7.4 ± 9.0 mL/min. The MTP-Patlak approach, featured with simplicity, is feasible in a clinically indicated CT examination for the evaluation of split renal function.

1. Perspective view southwest of filtration bed with earth mounded ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. Perspective view southwest of filtration bed with earth mounded over facility. Armory Street appears in the foreground. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

Use of Excel ion exchange equilibrium solver with WinGEMS to model and predict NPE distribution in the Mead/Westvaco Evandale, TX, hardwood bleach plant

Treesearch

Christopher Litvay; Alan Rudie; Peter Hart

2003-01-01

An Excel spreadsheet developed to solve the ion-exchange equilibrium in wood pulps has been linked by dynamic data exchange to WinGEMS and used to model the non-process elements in the hardwood bleach plant of the Mead/Westvaco Evandale mill. Pulp and filtrate samples were collected from the diffusion washers and final wash press of the bleach plant. A WinGEMS model of...

Fluorometric Method for Determining the Efficiency of Spun-Glass Air Filtration Media

PubMed Central

Sullivan, James F.; Songer, Joseph R.; Mathis, Raymond G.

1967-01-01

The procedures and equipment needed to measure filtration efficiency by means of fluorescent aerosols are described. The filtration efficiency of individual lots of spun-glass air filtration medium or of entire air filtration systems employing such media was determined. Data relating to the comparative evaluation of spun-glass filter media by means of the fluorometric method described, as well as by conventional biological procedures, are presented. PMID:6031433

Optimization of conventional water treatment plant using dynamic programming.

PubMed

Mostafa, Khezri Seyed; Bahareh, Ghafari; Elahe, Dadvar; Pegah, Dadras

2015-12-01

In this research, the mathematical models, indicating the capability of various units, such as rapid mixing, coagulation and flocculation, sedimentation, and the rapid sand filtration are used. Moreover, cost functions were used for the formulation of conventional water and wastewater treatment plant by applying Clark's formula (Clark, 1982). Also, by applying dynamic programming algorithm, it is easy to design a conventional treatment system with minimal cost. The application of the model for a case reduced the annual cost. This reduction was approximately in the range of 4.5-9.5% considering variable limitations. Sensitivity analysis and prediction of system's feedbacks were performed for different alterations in proportion from parameters optimized amounts. The results indicated (1) that the objective function is more sensitive to design flow rate (Q), (2) the variations in the alum dosage (A), and (3) the sand filter head loss (H). Increasing the inflow by 20%, the total annual cost would increase to about 12.6%, while 20% reduction in inflow leads to 15.2% decrease in the total annual cost. Similarly, 20% increase in alum dosage causes 7.1% increase in the total annual cost, while 20% decrease results in 7.9% decrease in the total annual cost. Furthermore, the pressure decrease causes 2.95 and 3.39% increase and decrease in total annual cost of treatment plants. © The Author(s) 2013.

30. Valves under central corridor of filtration bed building. Main ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. Valves under central corridor of filtration bed building. Main flood valves is at left and crossover valve is a right. - Lake Whitney Water Filtration Plant, Filtration Plant, South side of Armory Street between Edgehill Road & Whitney Avenue, Hamden, New Haven County, CT

Applications of NIR spectroscopy to monitoring and analyzing the solid state during industrial crystallization processes.

PubMed

Févotte, G; Calas, J; Puel, F; Hoff, C

2004-04-01

Fiber-optic near infrared (NIR) spectroscopy was used to investigate several key features of the polymorphic transitions observed during the crystallization and the filtration of SaC, an Active Pharmaceutical Ingredient (API) produced by Sanofi-Synthelabo. Using few samples, the spectroscopic data were calibrated to provide measurements of the polymorphic composition of the solid product which is likely to appear in two crystalline forms or in the amorphous state. Both qualitative and quantitative methods were successfully evaluated to characterize the API. The NIR spectroscopy measurement was then applied to investigate the kinetic behavior of the phase transition phenomena against various operating conditions. From the viewpoint of industrial process development several applications are presented. The effects of temperature and seed crystal habits on the rate of transition of filtration cakes are briefly investigated; and a study of the effect of residual water in the solvent on the transition occurring during filtration is more deeply analyzed. The experimental results demonstrate that highly valuable information can be provided by the NIR spectroscopy measurements, when one aims at understanding more deeply and optimizing the consequences of various and complex phenomena involved during the solid processing chain.

A comparison of instrumental dewatering methods for the separation and concentration of suspended sediment for subsequent trace element analysis

USGS Publications Warehouse

Horowitz, A.J.; Elrick, K.A.; Hooper, R.C.

1989-01-01

The continuous-flow centrifuges can process whole water at an influent feed rate of 41 per minute; however, when suspended sediment concentrations are low (<30 mg l-1), when small volumes of whole water are to be processed (30 to 401), or when suspended sediment mean grain size is very fine (<10 ??m), influent feed rates of 21 per minute may be more efficient. Tangential-flow filtration can be used to process samples at the rate of 11 per minute. -from Authors

Novel Renal Biomarkers to Assess Cardiorenal Syndrome

PubMed Central

Brisco, Meredith A.; Testani, Jeffrey M.

2014-01-01

Renal dysfunction (RD) in heart failure portends adverse outcomes and often limits aggressive medical and decongestive therapies. Despite the high prevalence in this population, not all forms of RD are prognostically or mechanistically equivalent: RD can result from irreversible nephron loss secondary to diabetic or hypertensive kidney disease or it can develop secondary to the HF itself, i.e. the cardiorenal syndrome. Furthermore, filtration is only one aspect of renal performance such that significant renal impairment secondary to cardiorenal syndrome can exist despite a normal glomerular filtration rate. Renal biomarkers have the potential to inform some of the intricacies involved in accurately assessing cardiorenal interactions. This article discusses novel biomarkers for cardiorenal syndrome and their utility in prognosis, diagnosis, and targeted treatment of heart failure-induced RD. PMID:25239434

Measuring and Assessing Kidney Function.

PubMed

Vart, Priya; Grams, Morgan E

2016-07-01

Assessment of kidney function is important for the detection and management of chronic kidney disease. The glomerular filtration rate (GFR) and level of albuminuria are two frequently used indices of kidney function assessment. Administration of an exogenous filtration marker to measure GFR and collection of urine for 24 hours to measure albumin excretion generally are considered the gold standard for GFR and albuminuria, respectively, but they are time consuming and onerous for the patient. Thus, in routine clinical practice, other methods are used more frequently to assess GFR and albuminuria. In this review, we discuss the role of GFR and albuminuria in staging of chronic kidney disease as well as the pros and cons and prognostic implications of various methods of assessment of GFR and albuminuria. Copyright © 2016 Elsevier Inc. All rights reserved.

Effect of porous material heating on the drag force of a cylinder with gas-permeable porous inserts in a supersonic flow

NASA Astrophysics Data System (ADS)

Mironov, S. G.; Poplavskaya, T. V.; Kirilovskiy, S. V.

2017-10-01

The paper presents the results of an experimental investigation of supersonic flow around a solid cylinder with a gas-permeable porous insert on its front end and of supersonic flow around a hollow cylinder with internal porous inserts in the presence of heating of the porous material. The experiments were performed in a supersonic wind tunnel with Mach number 4.85 and 7 with porous inserts of cellular-porous nickel. The results of measurements on the filtration stand of the air filtration rate through the cellular-porous nickel when it is heated are also shown. For a number of experiments, numerical modeling based on the skeletal model of a cellular-porous material was carried out.

Filter aids influence on pressure drop across a filtration system

NASA Astrophysics Data System (ADS)

Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

2017-06-01

Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

Aldosterone and glomerular filtration – observations in the general population

PubMed Central

2014-01-01

Background Increasing evidence suggests that aldosterone promotes renal damage. Since data on the association between aldosterone and renal function in the general population are sparse, we chose to address this issue. We investigated the associations between the plasma aldosterone concentration (PAC) or the aldosterone-to-renin ratio (ARR) and the estimated glomerular filtration rate (eGFR) in a sample of adult men and women from Northeast Germany. Methods A study population of 1921 adult men and women who participated in the first follow-up of the Study of Health in Pomerania was selected. None of the subjects used drugs that alter PAC or ARR. The eGFR was calculated according to the four-variable Modification of Diet in Renal Disease formula. Chronic kidney disease (CKD) was defined as an eGFR <60 ml/min/1.73 m2. Results Linear regression models, adjusted for sex, age, waist circumference, diabetes mellitus, smoking status, systolic and diastolic blood pressures, serum triglyceride concentrations and time of blood sampling revealed inverse associations of PAC or ARR with eGFR (ß-coefficient for log-transformed PAC −3.12, p < 0.001; ß-coefficient for log-transformed ARR −3.36, p < 0.001). Logistic regression models revealed increased odds for CKD with increasing PAC (odds ratio for a one standard deviation increase in PAC: 1.35, 95% confidence interval: 1.06-1.71). There was no statistically significant association between ARR and CKD. Conclusion Our study demonstrates that PAC and ARR are inversely associated with the glomerular filtration rate in the general population. PMID:24612948

Glomerular filtration rate in evaluation of the effect of iodinated contrast media on renal function.

PubMed

Becker, Joshua; Babb, James; Serrano, Manuel

2013-04-01

The purpose of this study was to use measured glomerular filtration rate (GFR), the reference standard of renal function, to assess the deleterious effect of iodinated contrast media on renal function. Such an effect has been traditionally defined as a greater than 0.5-mg/dL increase in serum creatinine concentration or a 25% or greater increase 24-72 hours after the injection of iodinated contrast medium. This pilot investigation was focused on the consequences of clinically indicated IV injection of iodinated contrast media; intraarterial injection was excluded. One hundred thirteen patients with normal serum creatinine concentrations were enrolled in an approved protocol. At random, as chosen by one of the investigators, patients underwent imaging with one of three monomeric agents (iopamidol 300, iopromide 300, iohexol 300) and one dimeric agent (iodixanol 320). Measured GFR was determined immediately before CT and approximately 3 and 72 hours after the contrast injection for the CT examination. Iodinated contrast medium, a glomerular filtrate with no tubular excretion or reabsorption, was the GFR marker. Measured GFR was determined by x-ray fluorescence analysis with nonisotopic iodinated contrast media. Monomeric and dimeric contrast agents in diagnostic CT volumes (based on bodyweight and imaging protocol) did not induce a significant change in measured GFR (95% confidence by Wilcoxon test), suggesting that use of the evaluated contrast media will not lead to more than a 12% variation. The three monomeric agents studied and the one dimeric agent were equivalent in terms of lack of a significant effect on measured GFR when administered to patients with a normal GFR.

Development of low-cost technology for the removal of iron and manganese from ground water in siwa oasis.

PubMed

El-Naggar, Hesham M

2010-01-01

Ground water is the only water resource for Siwa Oasis. It is obtained from natural freshwater wells and springs fed by the Nubian aquifer. Water samples collected from Siwa Oasis had relatively higher iron (Fe) and manganese (Mn) than the permissible limits specified in WHO Guidelines and Egyptian Standards for drinking water quality. Aeration followed by sand filtration is the most commonly used method for the removal of iron from ground water. The study aimed at development of low-cost technology for the removal of iron and manganese from ground water in Siwa Oasis. The study was carried out on Laboratory-scale columns experiments sand filters with variable depths of 15, 30, 45, 60, 75, 90 cm and three graded types of sand were studied. The graded sand (E.S. =0.205 mm, U.C. =3.366, depth of sand = 60 cm and filtration rate = 1.44 m3/m2/hr) was the best type of filter media. Iron and manganese concentrations measured in ground water with aeration only, decreased with an average removal percentage of 16%, 13% respectively. Iron and manganese concentrations after filtration with aeration came down to 0.1123, 0.05 mg/L respectively in all cases from an initial concentration of 1.14, 0.34 mg/L respectively. Advantages of such treatment unit included simplicity, low cost design, and no need for chemical addition. In addition, the only maintenance required was periodic washing of the sand filter or replacement of the sand in order to maintain reasonable flow rate through the system.

Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudd, Armin; Bergey, Daniel

In this project, Building America research team Building Science Corporation tested the effectiveness of ventilation systems at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. This was because the sourcemore » of outside air was not direct from outside, the ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four system factor categories: balance, distribution, outside air source, and recirculation filtration. Recommended system factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.« less

Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rudd, Armin; Bergey, Daniel

Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow. Cumulative particle counts for six particle sizes, and formaldehyde and other Top 20 VOC concentrations were measured in multiple zones. The testing showed that single-point exhaust ventilation was inferior as a whole-house ventilation strategy. It was inferior because the source of outside air was not direct from outside, themore » ventilation air was not distributed, and no provision existed for air filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, and filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs. System improvement percentages were estimated based on four System Factor Categories: Balance, Distribution, Outside Air Source, and Recirculation Filtration. Recommended System Factors could be applied to reduce ventilation fan airflow rates relative to ASHRAE Standard 62.2 to save energy and reduce moisture control risk in humid climates. HVAC energy savings were predicted to be 8-10%, or $50-$75/year.« less

Prevalence of chronic kidney disease among patients undergoing transradial percutaneous coronary interventions.

PubMed

Hossain, Mohammad A; Quinlan, Amy; Heck-Kanellidis, Jennifer; Calderon, Dawn; Patel, Tejas; Gandhi, Bhavika; Patel, Shrinil; Hetavi, Mahida; Costanzo, Eric J; Cosentino, James; Patel, Chirag; Dewan, Asa; Kuo, Yen-Hong; Salman, Loay; Vachharajani, Tushar J

2018-07-01

While transradial approach to conduct percutaneous coronary interventions offers multiple advantages, the procedure can cause radial artery damage and occlusion. Because radial artery is the preferred site for the creation of an arteriovenous fistula to provide dialysis, patients with chronic kidney disease are particularly dependent on radial artery for their long-term survival. In this retrospective study, we investigated the prevalence of chronic kidney disease in patients undergoing coronary interventions via radial artery. Stage of chronic kidney disease was based on estimated glomerular filtration rate and National Kidney Foundation - Kidney Disease Outcomes Quality Initiative guidelines. A total of 497 patients undergoing transradial percutaneous coronary interventions were included. Over 70.4% (350/497) of the patients had chronic kidney disease. Stage II chronic kidney disease was observed in 243 (69%) patients (estimated glomerular filtration rate = 76.0 ± 8.4 mL/min). Stage III was observed in 93 (27%) patients (estimated glomerular filtration rate = 49 ± 7.5 mL/min). Stage IV chronic kidney disease was observed in 5 (1%) patients (estimated glomerular filtration rate = 25.6 ± 4.3 mL/min) and Stage V chronic kidney disease was observed in 9 (3%) patients (estimated glomerular filtration rate = 9.3 ± 3.5 mL/min). Overall, 107 of 350 patients (30%) had advanced chronic kidney disease, that is, stage III-V chronic kidney disease. Importantly, 14 of the 107 (13%) patients had either stage IV or V chronic kidney disease. This study finds that nearly one-third of the patients undergoing transradial percutaneous coronary interventions have advanced chronic kidney disease. Because many of these patients may require dialysis, the use of radial artery to conduct percutaneous coronary interventions must be carefully considered in chronic kidney disease population.

Renal function and size at young adult age after intrauterine growth restriction and very premature birth.

PubMed

Keijzer-Veen, Mandy G; Kleinveld, Hilda A; Lequin, Maarten H; Dekker, Friedo W; Nauta, Jeroen; de Rijke, Yolanda B; van der Heijden, Bert J

2007-10-01

Premature birth and intrauterine growth restriction may increase the risk of developing renal disease at adult age. Renal function may already be impaired at young adult age. Cross-sectional study. Very premature individuals (gestational age < 32 weeks) recruited from Project on Premature and Small for Gestational Age Infants and full-term-born controls (37 to 42 weeks) recruited from a children's hospital in Rotterdam, The Netherlands. All individuals were 20 years of age at the time of study. Gestational age and birth weight: premature and small for gestational age (SGA; n = 23), premature and appropriate for gestational age (n = 29), and controls (n = 30). Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and filtration fraction before and after renal stimulation with low-dose dopamine infusion and oral amino-acid intake. Urine albumin and renal ultrasound. Height, weight, kidney length and volume, GFR, and ERPF were significantly lower in the SGA group than in controls. After adjustment for body surface area, GFR did not differ significantly among groups. Mean ERPF was 71 mL/min/1.73 m(2) (95% confidence interval [CI], 3 to 139) less, but filtration fraction was only 1.3% (95% CI, -0.3 to 3.0) greater, in the SGA group than controls. Renal stimulation significantly increased GFR and ERPF and decreased filtration fraction in all groups. After renal stimulation, ERPF was 130 mL/min/1.73 m(2) (95% CI, 21 to 238) greater in the SGA group than controls, but GFR and filtration fraction did not differ significantly among groups. Microalbuminuria was present in 2 patients (8.7%) in the SGA group, but none in the appropriate-for-gestational-age group or controls. Renal function correlated with renal size. Small sample size. Our findings do not fully support the hypothesis that preterm birth in combination with intrauterine growth restriction contributes to renal function alterations at young adult age. Larger studies are needed to evaluate this hypothesis.

METC CFD simulations of hot gas filtration

DOE Office of Scientific and Technical Information (OSTI.GOV)

O`Brien, T.J.

1995-06-01

Computational Fluid Dynamic (CFD) simulations of the fluid/particle flow in several hot gas filtration vessels will be presented. These simulations have been useful in designing filtration vessels and in diagnosing problems with filter operation. The simulations were performed using the commercial code FLUENT and the METC-developed code MFIX. Simulations of the initial configuration of the Karhula facility indicated that the dirty gas flow over the filter assemblage was very non-uniform. The force of the dirty gas inlet flow was inducing a large circulation pattern that caused flow around the candles to be in opposite directions on opposite sides of themore » vessel. By introducing a system of baffles, a more uniform flow pattern was developed. This modification may have contributed to the success of the project. Several simulations of configurations proposed by Industrial Filter and Pump were performed, varying the position of the inlet. A detailed resolution of the geometry of the candles allowed determination of the flow between the individual candles. Recent simulations in support of the METC/CeraMem Cooperative Research and Development Agreement have analyzed the flow in the vessel during the cleaning back-pulse. Visualization of experiments at the CeraMem cold-flow facility provided confidence in the use of CFD. Extensive simulations were then performed to assist in the design of the hot test facility being built by Ahlstrom/Pyropower. These tests are intended to demonstrate the CeraMem technology.« less

A Review of Podocyte Biology.

PubMed

Garg, Puneet

2018-05-31

Podocyte biology is a developing science that promises to help improve understanding of the mechanistic nature of multiple diseases associated with proteinuria. Proteinuria in nephrotic syndrome has been linked to mechanistic dysfunctions in the renal glomerulus involving the function of podocyte epithelial cells, including podocyte foot process effacement. Developments in imaging technology are improving knowledge of the detailed structure of the human renal glomerulus and cortex. Podocyte foot processes attach themselves to the glomerular capillaries at the glomerular basement membrane (GBM) forming intercellular junctions that form slit diaphragm filtration barriers that help maintain normal renal function. Damage in this area has been implicated in glomerular disease. Injured podocytes undergo effacement whereby they lose their structure and spread out, leading to a reduction in filtration barrier function. Effacement is typically associated with the presence of proteinuria in focal segmental glomerulosclerosis, minimal change disease, and diabetes. It is thought to be due to a breakdown in the actin cytoskeleton of the foot processes, complex contractile apparatuses that allow podocytes to dynamically reorganize according to changes in filtration requirements. The process of podocyte depletion correlates with the development of glomerular sclerosis and chronic kidney disease. Focal adhesion complexes that interact with the underlying GBM bind the podocytes within the glomerular structure and prevent their detachment. Key Messages: Knowledge of glomerular podocyte biology is helping to advance our understanding of the science and mechanics of the glomerular filtering process, opening the way to a variety of new potential applications for clinical targeting. © 2018 S. Karger AG, Basel.