Optimization of RDM-UF for alfalfa wastewater treatment using RSM.

Rotating disk membrane (RDM) module with ultrafiltration (UF) was an effective alternative method to treat alfalfa wastewater and realize protein recovery and agricultural irrigation water production. A scientific investigation has been conducted to comprehend the effect of operation conditions (feed flow rate, shear rate, transmembrane pressure (TMP), and temperature) on alfalfa wastewater treatment with RDM-UF by central composite response surface methodology (CCRSM). First, the filtration behaviors of three types of UF membranes (PES20, UH030P, and PES50) were studied to select the optimized membrane (UH030P).

Indirect prediction of total body water content in healthy adult Beagles by single-frequency bioelectrical impedance analysis.

Objective: To develop equations for prediction of total body water (TBW) content in unsedated dogs by combining impedance (resistance and reactance) and morphological variables and to compare the results of those equations with TBW content determined by deuterium dilution (TBW(d)).

Animals: 26 healthy adult Beagles.

Procedures: TBW content was determined directly by deuterium dilution and indirectly with equations developed from measurements obtained by use of a portable bioelectric impedance device and morphological variables including body length, height, weight, and thoracic and abdominal circumferences.

Factors influencing accuracy and reproducibility of body resistance measurements by foot-to-foot impedancemeters.

The electronics of a BodySignal V2 (Tefal, France) foot-to-foot impedancemeter (FFI) was modified to display the foot-to-foot resistance instead of body fat. This device was connected to electrodes of different sizes mounted on a podoscope permitting photographs of subjects feet soles and electrodes in order to calculate the contact area between feet and electrodes. The foot-to-foot resistance was found to decrease when the contact area of feet with current and voltage electrodes increased.

Accuracy of plantar electrodes compared with hand and foot electrodes in fat-free-mass measurement.

This paper investigates the measurement of fat-free mass (FFM) by bioimpedance using foot-to-foot impedancemeters (FFI) with plantar electrodes measuring the foot-to-foot resistance R34 and hand-to-foot medical impedancemeters. FFM measurements were compared with corresponding data using Dual X-ray absorptiometry (DXA). Equations giving FFM were established using linear multiple regression on DXA data in a first group of 170 subjects.

A comparison of bicarbonate kinetics and acid-base status in high flux hemodialysis and on-line post-dilution hemodiafiltration.

Objectives: To compare bicarbonate kinetics and acid base status in HD and HDF for the same patient; and to investigate the effect of patient physiologic parameters on these kinetics.

Methods: In order to monitor HCO3- kinetics during dialysis, acid-base parameters, pH, blood gases partial pressures, and HCO3- concentrations were recorded during 3 regular dialysis (HD) and 3 on-line post-dilution HDF sessions performed on 12 patients, using same dialysis fluid with a 38 mmol/l HCO3- concentration. HCO3- mass transfers through the hemodialyzers membranes and into the patients were continuously calculated during the sessions from HCO3- concentrations, together with HCO3-dialysance.

Comparison of body fat-free masses calculated from hand-to-foot and foot-to-foot resistances with DXA measurements.

This article compares the determination of body fat-free-mass (FFM) by impedance, using either hand-to-foot resistance (R₁₃) or foot-to-foot one (R₃₄) from comparison with dual X-ray absorptiometry (DXA) measurements in a normal population. The first goal was to see if the foot-to-foot resistance used in body fat analysers provides less accurate information for body FFM than the hand-to-foot one used by medical impedance-meters. Another goal was to compare the prediction accuracy of six different regression equations of FFM for each sex and for each resistance relatively to DXA.

A two-stage ultrafiltration and nanofiltration process for recycling dairy wastewater.

A two-stage ultrafiltration and nanofiltration (UF/NF) process for the treatment of model dairy wastewater was investigated to recycle nutrients and water from the wastewater. Ultracel PLGC and NF270 membranes were found to be the most suitable for this purpose. In the first stage, protein and lipid were concentrated by the Ultracel PLGC UF membrane and could be used for algae cultivation to produce biodiesel and biofuel, and the permeate from UF was concentrated by the NF270 membrane in the second stage to obtain lactose in retentate and reusable water in permeate, while the NF retentate could be recycled for anaerobic digestion to produce biogas.

A comparison between two methods for measuring limb resistances with wrist and ankle electrodes.

Segmental measurements of limb resistances permit to evaluate the regional distribution of fat-free-mass (FFM). As shown by Organ et al. (J Appl Physiol 1994;77:98-112) "virtual" limb resistances can be measured with only peripheral electrodes at ankle and wrist, which is faster and does not require undressing.

Separation of water from metal working emulsions by ultrafiltration using vibratory membranes.

In this paper, we investigate the application of a vibratory shear-enhanced filtration system (VSEP) to separation of water from oil-in-water emulsions. The VSEP module consists in an annular membrane of 500 cm(2) area which oscillates azimuthally in its own plane with an amplitude depending upon frequency. Polyethersulfone (PES) membranes of 50 and 20 kDa were used.

In vitro tests and modelization of bicarbonate kinetics and mass transfers during online hemodiafiltration.

This paper proposes an in vitro hemodiafiltration (HDF) model in which the patient is represented by a 2 L bag of fresh heparinized bovine blood circulated by a 4008H monitor through a 0.6 m2 hemodialyzer to investigate kinetics of bicarbonate (HCO,) during online post-dilution HDF. Five tests were carried out, with three ultrafiltration rates, zero (HD test), 30 and 50 ml/min.

Measurements of body composition in limbs and trunk using a eight contact electrodes impedancemeter.

Regional body composition measurements may be achieved in a single operation with impedancemeters equipped with four plantar and four hand electrodes. By measuring sequentially the resistances of five current lines connecting the hands and feet and solving a system of five linear equations, it is possible to calculate the resistances of each limb and the trunk. The impedancemeter used in this study was a prototype with four plantar electrodes and four additional contact electrodes for the hands.

Body composition determination by bioimpedance: an update.

Purpose Of Review: To review various methods for measuring body composition by bioimpedance and their limitations, as well as available impedance meters, including body fat analyzers for home use.

Recent Findings: Bioimpedance spectroscopy, which requires multifrequency impedance meters, is preferable for fluid volume measurements, especially extracellular fluid, whereas bioimpedance analysis at 50 kHz is more widely used for measuring fat-free mass. A method for using bioimpedance spectroscopy equations with 50 kHz impedance meters has been recently proposed and successfully tested.

Extracellular volume measurements using bioimpedance spectroscopy-Hanai method and wrist-ankle resistance at 50 kHz.

A method for extrapolating the extracellular water (ECW) resistance from wrist-ankle resistance at 50 kHz (R (50)) is proposed in this paper, in order to enable 50 kHz impedancemeters to use the BIS-Hanai equation for determination of ECW. Values of R (50) and the ECW resistance extrapolated at zero frequency R (e) were measured in a first group of 57 healthy volunteers, using a Xitron 4200 multifrequency impedancemeter and mean values (b) of the ratio R (50)/R (e) in men and women were used to determine individual values of R (e50), the ECW resistance extrapolated from R (50), which were substituted to R (e) in the BIS-Hanai equation. For validation, the method was compared against ECW measured with the Xitron (V (ex)) in a second group of 31 healthy volunteers, using values of b of first group.

Body fluid volumes measurements by impedance: A review of bioimpedance spectroscopy (BIS) and bioimpedance analysis (BIA) methods.

This paper reviews various bioimpedance methods permitting to measure non-invasively, extracellular, intracellular and total body water (TBW) and compares BIA methods based on empirical equations of the wrist-ankle resistance or impedance at 50 kHz, height and weight with BIS methods which rely on an electrical model of tissues and resistances measured at zero and infinite frequencies. In order to compare these methods, impedance measurements were made with a multifrequency Xitron 4200 impedance meter on 57 healthy subjects which had undergone simultaneously a Dual X-ray absorptiometry examination (DXA), in order to estimate their TBW from their fat-free-mass. Extracellular (ECW) and TBW volumes were calculated for these subjects using the original BIS method and modifications of Matthie[Matthie JR.

A bridge from bioimpedance spectroscopy to 50 kHz bioimpedance analysis: application to total body water measurements.

This paper presents a method for extrapolating the total body water (TBW) resistance R(t50) from the resistance measured at 50 kHz (R(50)). A DXA examination and impedance measurements were carried out in a 1st group of 57 healthy volunteers with a Xitron 4200 multifrequency impedancemeter, in order to determine their values of R(t50) by comparison with resistances extrapolated at an infinite frequency by the Xitron (R(infinity)). TBW volumes were calculated using our modified BIS method (Jaffrin et al 2006 Med.

Assessment of body composition in adolescent subjects with anorexia nervosa by bioimpedance.

Our main goal was to test various impedance methods for measuring body composition in adolescents with anorexia nervosa (AN) during refeeding therapy. A specific objective was to compare the information provided by a foot-to-foot impedancemeter (FFI) with that supplied by a medical multifrequency impedancemeter and by dual X-ray absorptiometry (DXA). We have monitored 13 young AN subjects and 17 healthy controls of a similar age group using a Xitron 4200 multifrequency impedancemeter measuring extracellular (ECW) and total body water (TBW) volumes and a Tefal Bodymaster FFI measuring weight (W), fat-free-mass (FFM) and body fat mass (FM).

Measurements of total body water with a foot-to-foot impedancemeter.

The objective was to set-up a method for measuring total body water volumes (TBW) using a Tefal foot-to-foot impedancemeter (FFI) by comparison with a multifrequency medical impedancemeter and to validate this method against deuterium dilution data. The investigation was carried out in 57 Caucasian adult subjects. Impedancemeters were a Tefal Bodymaster Vision (foot-to-foot) featuring a square wave signal and a Xitron Hydra 4200 (5-1000 kHz) using BIS method.

Total body water measurement by a modification of the bioimpedance spectroscopy method.

We propose a method for calculating directly total body water (TBW) volumes (V (t)) from whole body resistance extrapolated at infinite frequency (R (infinity)) using a XITRON 4200 impedance meter. Mean TBW resistivities for men and women were determined from measurements of R (infinity) and fat-free mass (FFM(d)) measured by DXA in 58 healthy subjects assuming an average hydration coefficient of 73.2%.

Evaluation of a foot-to-foot impedance meter measuring extracellular fluid volume in addition to fat-free mass and fat tissue mass.

Objectives: The first objective was to compare the accuracy of a foot-to-foot impedance meter with a multifrequency bioimpedance for measurements of fat-free mass (FFM) and fat mass (FM) using dual energy X-ray absorptiometry (DXA) as reference. The second objective was to validate measurements of extracellular water resistance and volume by the foot-to-foot impedance meter, using multifrequency bioimpedance as reference.

Methods: This investigation was carried out in 60 volunteers 18 to 71 y of age.

Mass transfers in a fluidized bed bioreactor using alginate beads for a future bioartificial liver.

Fluidized bed bioreactor with alginate beads may be an alternative to hollow fiber cartridge to host hepatocytes for bioartificial liver purposes. After the bioreactor design and the characterization of fluid mechanics, the present study was aimed at analyzing bi-directional mass transfers of calibrated species between external fluid and empty beads. Static (batch) and dynamic (fluidized bed bioreactor) experimental conditions were analyzed.

Extracellular and intracellular volume variations during postural change measured by segmental and wrist-ankle bioimpedance spectroscopy.

Extracellular (ECW) and intracellular (ICW) volumes were measured using both segmental and wrist-ankle (W-A) bioimpedance spectroscopy (5-1000 kHz) in 15 healthy subjects (7 men, 8 women). In the 1st protocol, the subject, after sitting for 30 min, laid supine for at least 30 min. In the second protocol, the subject, who had been supine for 1 hr, sat up in bed for 10 min and returned to supine position for another hour.

Microfiltration and ultrafiltration of polysaccharides produced by fermentation using a rotating disk dynamic filtration system.

The recovery of exopolysaccharides (EPS) produced by Sinorhizobium meliloti bacteria by dynamic microfiltration was investigated using a rotating disk device designed in our laboratory, equipped with a 0.2 microm nylon membrane. This system differs from commercially available systems by the presence of vanes on the disk which produce a very important increase in permeate flux while yielding excellent EPS transmission.

Continuous monitoring of plasma, interstitial, and intracellular fluid volumes in dialyzed patients by bioimpedance and hematocrit measurements.

Bioimpedance spectroscopy (BIS) permits evaluation of extra- and intracellular fluid volumes in patients. We wished to examine whether this technique, used in combination with hematocrit measurement, can reliably monitor fluid transfers during dialysis. Ankle to wrist BIS measurements were collected during 21 dialysis runs while hematocrit was continuously monitored in the blood line by an optical device.

Reversibility of artifacts of fluid volume measurements by bioimpedance caused by position changes during dialysis.

The effect of temporary position changes, sitting up from supine, on extracellular (ECW) and intracellular (ICW) resistances and fluid volumes calculated from whole body bioimpedance using a Xitron 4200 impedancemeter was investigated on 8 patients during dialysis for a total of 11 tests. It was found that ECW resistance decreased instantaneously by an average of 2.3% when the patient sits up, due to plasma and interstitial fluid shift into the legs which decreases leg resistance, the major contributor to total resistance.