Dialysis Process Research Articles

Effect of the chromium ion diffusion in polyacrylamide/chromium acetate gelation system with surrounding water on gelation behavior

The diffusion of Cr3+ from the Cr3+/HPAM system is simulated by quantifying the entrapment ability of the Cr3+ after dialysis analysis through a dialysis bag method to study the Cr3+ diffusion effect on the gelation types. After the gelant is put in the dialysis bag surrounded by the solvents, only the diffusion of the aqueous ions are allowed, which eventually can be detected in the dialysate. By monitoring the gelants with varying initial contents, we find that the Cr3+ dialysis kinetics and total dialyzed amount are changed. In this particular experiment, the gelation types are classified and the classification result differences for the same gelant with or without dialysis process are investigated and compared. In this study, we assess the gelant contents in terms of possible limiting scenarios for successful gelation and discuss their gelation results influenced by the Cr3+ diffusion The results demonstrate that Cr3+ diffusion, in different extent, influences the gelation types and gelation time of the Cr3+/HPAM systems with varying HPAM molecular weight (MW), the Cr3+ initial concentration, the initial HPAM polymer concentration, or the degree of initial HPAM hydrolysis. Along with the gelation types and the accompanying morphological study, determine the relationships between the initial Cr3+ concentration and the true Cr3+ concentration entrapped on the polymers are possible, which are pretty distinct from each other. Neglecting to consider such diffusion effects will lead to overestimating of the crosslinking results. In addition, a sorption model is used to demonstrate the sorption trend changes before and after the gelation time.

Longitudinal profile of circulating T follicular helper lymphocytes parallels anti-HLA sensitization in renal transplant recipients.

Antibody-mediated rejection is responsible for 30%-50% of renal graft failures. Differentiation of B cells into antibody-producing plasmablasts depends on the collaboration of follicular helper T cells (Tfh). We analyzed circulating Tfh (cTfh) in kidney recipients and studied cTfh relationship with anti-HLA antibody production and graft outcome. cTfh were longitudinally analyzed in a prospective cohort of patients (n=206), pre- and posttransplantation. Clinical data, HLA sensitization, and cTfh function were recorded. Both pretransplant and 6-month posttransplant cTfh were able to derive IgG-producing plasmablasts. Pretransplant cTfh was decreased in patients, especially in those who received dialysis. However, these cells were increased in patients with previous allograft or transfusions and in HLA-sensitized recipients. After transplantation cTfh expanded, significantly more in patients who developed de novo anti-HLA antibodies than in patients who remained unsensitized. Augmented pretransplant cTfh positively correlated with higher intensity of pretransplant anti-HLA class I and with de novo anti-HLA class I and anti-HLA class II antibodies. Consistently, pretransplantation cTfh were higher in patients who experienced acute rejection (HR=1.14 [1.04-1.25]). Thus, we show a role for Tfh in anti-HLA sensitization and rejection. Multicenter studies with additional patient cohorts are needed to validate these results. Immunosuppressive drugs targeting Tfh could be useful to improve outcomes.

Patients receiving dialysis do not have increased energy needs compared with healthy adults.

Patients receiving dialysis are thought to have increased energy needs due to stress from the dialysis process or uraemic toxins. However, certain conditions may induce hypometabolic states potentially leading to unwanted weight gains when increased calorie intake is recommended. Since there is conflicting research, this study aims to assess total energy expenditure (TEE) of patients receiving dialysis through analysis of resting energy expenditure (REE) and physical activity levels. Comprehensive review of the current literature on REE and physical activity levels. Two electronic databases (PubMed and CINAHL) were searched using keywords to find papers published within the last 10 years for physical activity studies and within the last five years for REE. Adults undergoing long-term dialysis treatments who do not have comorbidities that influence energy expenditure such as inflammation, hyperthyroidism or cancers. Participants were also required to ambulate without assistance. Only seven of the 325 studies found were included in this review. Most studies were controlled trials with one being a prospective study. Patients receiving dialysis had rest energy expenditures comparable to healthy adults. There was not a consensus between studies as to which predictive energy equation produced accurate energy recommendations. Overall, patients receiving dialysis were significantly less active compared with healthy adults and this related to muscle mass. Patients receiving dialysis tend to be sedentary or lightly active and do not have increased energy expenditure compared with healthy adults. Therefore, stable patients should not be prescribed increased calorie intake.

Bioaccessibility analysis of anthocyanins and ellagitannins from blackberry at simulated gastrointestinal and colonic levels

The total bioaccessibility of the main phenolic compounds from blackberry fruit using an in vitro gastrointestinal model with colonic fermentation was investigated. The incorporation of a dialysis membrane before starting the fermentation phase was included with the aim of providing more correct bioaccessibility estimations at colonic level. Phenolic compounds in the raw material and in digested samples were analyzed by high-performance liquid chromatography. The intestinal bioaccessibility was 1.8% for the principal anthocyanin, cyanidin-3-O-glucoside, and less than 1% for the principal ellagitannins, lambertianin A and C. In contrast, this value was 14.9% for ellagic acid, due to its release from ellagitannin breakdown. The intestinal bioaccessibility of total polyphenols, calculated as the sum of indigenous phenolic compound contents, was 2.2%. After fermentation, only 1% of the indigenous individual polyphenols was potentially bioaccessible at colonic level. However, ellagic acid colonic bioaccessibility was around 10% due to the prevention of its further metabolization by dialysis process. Total bioaccessibility of the main blackberry polyphenols, calculated as the sum of intestinal and colonic bioaccessibility, was around 3.3%, indicating that gastrointestinal and colonic conditions affected the amount of the indigenous polyphenols and, consequently, their bioaccessibility as intact structures.

Preparation of cellulose colloidal particles in aqueous solution with good photochromic and photoluminescent performances by grafting a spiropyran derivative onto filter paper cellulose

The cellulose colloidal particles with good photochromic and photoluminescent performances had been developed in aqueous solution based on a spiropyran-grafted filter paper cellulose (SP–cellulose) in this study. The insoluble filter paper cellulose dramatically became soluble in ethanol after grafting a spiropyran derivative onto its backbone via esterification. During this process, the optical properties of the spiropyran had been successfully inherited. With the aid of ultraviolet and visible light, the obtained SP–cellulose colloidal particles showed light-induced tunability on both photochromism and photoluminescence, corresponding to the significant change of the spiropyran between weak polar ring-closed spiropyran and strong polar ring-opened zwitterionic merocyanine. Based upon this result, the SP–cellulose colloidal particles were finally obtained in water by follow-up dialysis process. In comparison to the pure spiropyran showing poor optical properties in mixed solvent of ethanol/water, the obtained SP–cellulose colloidal particles in water showed good photochromic and photoluminescent performances as well as fine stability. Considering also the raw material of filter paper being cheap and easy to get as well as the facile preparation process of the functional colloidal particles, our experimental results may bring about more promising applications of spiropyran species and water-insoluble cellulose in aqueous medium.

Fast technique for the purification of as-prepared graphene oxide suspension

Improved Hummer's method is widely used to prepare graphene oxide (GO), which is a precursor of graphene. Purification of as-prepared GO is challenging due to the used corrosive acidic media, large amounts of impurities are formed as byproducts during GO production, and the long time required for purification process. GO purification with traditional methods is difficult and time consuming. Novel methods for fast purification of as-prepared GO without pre-treatment was developed using commercially available hollow-fibre dialyzer (Phylther-1.7 m2). The dialyzer can be used several times in a crossflow filtration or dialysis process in the designed systems without deteriorating. The concentrations of impurities in GO suspension were monitored during purification process by measuring the ionic conductivity of the GO suspension. For process optimization, the factors affecting the purification methods were studied. The results showed that exfoliated GO can be purified in <1 h. Moreover, the concentration of purified GO was 6 mg/mL when using cross-flow filtration. X-ray diffraction (XRD), Fourier transform infrared (FTIR), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX) and atomic absorption spectroscopy (AAS) were used to characterize the purified GO. EDX results showed complete removal of potassium and phosphorous impurities, and only sulfur and manganese remained in GO. Mixing the purified FGO sample with HCl followed by a second stage of cross-flow filtration greatly reduced manganese and sulfur contents.

Divalent Cation Removal by Donnan Dialysis for Improved Reverse Electrodialysis.

Divalent cations in feedwater can cause significant decreases in efficiencies for membrane processes, such as reverse electrodialysis (RED). In RED, power is harvested from the mixing of river and seawater, and the obtainable voltage is reduced and the resistance is increased if divalent cations are present. The power density of the RED process can be improved by removing divalent cations from the fresh water. Here, we study divalent cation removal from fresh water using seawater as draw solution in a Donnan dialysis (DD) process. In this way, a membrane system with neither chemicals nor electrodes but only natural salinity gradients can be used to exchange divalent cations. For DD, the permselectivity of the cation exchange membrane is found to be crucial as it determines the ability to block salt leakage (also referred to as co-ion transport). Operating DD using a membrane stack achieved a 76% reduction in the divalent cation content in natural fresh water with residence times of just a few seconds. DD pretreated fresh water was then used in a RED process, which showed improved gross and net power densities of 9.0 and 6.3%, respectively. This improvement is caused by a lower fresh water resistance (at similar open circuit voltages), due to exchange of divalent for monovalent cations.

Assessment of dialysis adequacy: beyond urea kinetic measurements

Adequacy of dialysis is a term that has been used for many years based on measurement of small solute clearance using urea and creatinine. This has been shown in some but not all studies in adults to correlate with survival. However, small solute clearance is just one minor part of the effectiveness of dialysis and in fact ‘optimum’ dialysis, rather than ‘adequate’ dialysis is what most paediatric nephrologists would want for their patients. Additional ways to assess the success of dialysis in children would include dialysis access complications and longevity, preservation of residual kidney function, body composition, biochemical and haematological control, nutrition and growth, discomfort during the dialysis process and psychosocial adjustment including hospitalisation and school attendance. These criteria need to be balanced against a dialysis programme that has the least possible adverse effects on quality of life.

Exploring Solvent Effects on the Dialysis‐Induced Self‐Assembly of Nanostructured Tetra(aniline)

AbstractOne‐pot simple dialysis process was employed to explore the self‐assembly behavior of Ph/NH2‐capped tetra(aniline) (TANI) in five different solely organic solvents. Multi‐morphologies of supramolecular were assembled including nanoparticles, nanocapsules, hierarchical nanoflowers and nanowires. The solvent effects on the self‐assembly behavior were studied by differential scanning calorimetry (DSC), thermogravimetric analyzer (TGA), FT‐IR and UV‐Vis spectroscopies, 1H NMR and powder X‐ray diffraction (PXRD), as well as density functional theory (DFT) calculations. Investigations suggested that the increase of solvent polarity facilitated the formation of hydrogen bonding between solute‐solvate. Moreover, dialysis process was found to have a profound effect on forming intermolecular π‐π stacking interaction. Such results provided not only an insight into the formation mechanism and design rule of self‐assembly behavior of nanostructured oligo(aniline)s in organic solvent‐containing complex system, but also further understanding of dialysis‐induced self‐assembly system for other nanomaterials.

Does inflammation affect outcomes in dialysis patients?

Chronic, low-grade inflammation is a common comorbid condition in chronic kidney disease (CKD), and particularly in chronic dialysis patients. In this review, we consider the question of whether inflammation affects outcomes in dialysis patients. Levels of proinflammatory cytokines, as well as C-reactive protein, are elevated in chronic dialysis patients. Multiple factors likely contribute to chronic inflammatory activation in kidney disease patients including the uremic milieu, lifestyle and epigenetic influences, infectious and thrombotic events, the dialysis process, and dysbiosis. Increased inflammatory markers in both CKD and chronic dialysis patients are associated with adverse clinical outcomes including all-cause mortality, cardiovascular events, kidney disease progression, protein energy wasting and diminished motor function, cognitive impairment, as well as other adverse consequences including CKD-mineral and bone disorder, anemia, and insulin resistance. Strategies that have been shown to reduce chronic systemic inflammation in CKD and chronic dialysis patients include both pharmacological and nonpharmacological interventions. However, despite evidence that systemic inflammatory markers can be lowered in kidney disease patients treated with various strategies, evidence that this improves clinical outcomes is largely unavailable and represents an important future research direction. Overall, there is strong observational evidence that inflammation is high in chronic dialysis patients and that this is independently associated with numerous adverse clinical outcomes. Targeting inflammation represents a potentially novel and attractive strategy if it can indeed improve adverse outcomes common in this population.

Augmenting acid recovery from different systems by novel Q-DAN anion exchange membranes via diffusion dialysis

Abstract In this study, a series of novel anion exchange membranes composed of polyvinyl alcohol (PVA) and various amount of synthesized anion exchange precursor were successfully prepared and used for acid recovery by DD process. The anion exchange precursor (Q-DAN) was synthesized through reaction of 1,5-diaminonaphthalene (DAN) and 2,3-epoxypropyltrimethylammonium chloride (EPTC) which was confirmed by proton NMR. The dosage of Q-DAN inside membrane matrix played an important role to determine the electrochemical and physicochemical properties of Q-DAN AEMs. Influences of Q-DAN and multivalent metal ions on acid recovery were elaborated in detail. Acid dialysis coefficients (UH) values for FeCl2-HCl system were in the range of 0.0194–0.0295 m/h and separation factors were ranged from 27.84 to 52.60 at 25 °C. Furthermore, acid dialysis coefficient (3.28 times) and separation factor (2.84 times) were much greater than commercial membrane DF-120 (UH and S = 0.009 m/h and 18.5), respectively. Moreover, Q-DAN-4 membrane was selected to investigate the effects of multivalent metal ions on diffusion dialysis. The results showed that the presence of different metal salts in hydrochloric acid solution effect the membrane diffusivity and selectivity in diffusion dialysis process due to complexation of metal ions and acid.

Investigation of retention of undesirable organic matter from aqueous samples in stopped-flow dialysis procedures for inorganic anions

Sample preparation is a key issue in the analysis of many real samples using ion chromatography (IC). One of the many means of sample preparation that has received considerable attention in recent years is the stopped-flow in-line dialysis approach hyphenated to IC. Using appropriate dialysis membranes undesirable high-molecular weight compounds, colloids and dispersed particulate matter are retained whereas the analyte ions pass through the membrane and are separated and quantified by IC.However, in the many papers about analytical use of in-line dialysis (not only in connection with IC) the retention of undesirable compounds has never been quantified. This study is a first attempt to fil this gap. The breakthrough (BT) of humic acids (HA) and lignin as model compounds often contained in natural water samples was investigated in the stopped-flow dialysis procedure using different dialysis membranes. BT was measured and quantified by UV-absorption in the receiver solution leaving the dialysis cell. The most important factor for retention of undesired compounds is the pore size or the molecular weight cut-off (MWCO) of the dialysis membrane. In addition, the recovery of analytes in acceptable time needs to be considered. The optimized system addresses these two aspects and permits using the proper membrane almost quantitative recovery of several inorganic ions and at the same time almost complete retention of the model interferents. Artificial natural water samples were prepared and analyzed containing a mixture of HA, lignin and a surfactant and a number of anions. In long-term operation no alterations of the dialysis process occurred and no adverse effects in IC separations were observed.

Production of thermostable multiple enzymes from Bacillus amyloliquefaciens KUB29

A strain of Bacillus amyloliquefaciens KUB29 was identified by 16S ribosomal RNA sequencing (Genbank: MF772779.1). Production of thermostable protease, amylase and lipase were done by the isolated strain. The produced enzymes were partially purified by ammonium precipitation followed by dialysis process. Protease and lipase enzymes are effectively used in bio-oil extraction from proteinaceous sample followed by transesterification to produce methyl ester. Amylase enzyme is widely used in food and laundry industry. The produced enzymes are active at thermophilic condition of 55 °C. Use of these enzymes in biofuel production process will make the process cleaner and greener.

Continuous dialysis of hydrochloric acid and lithium chloride: permeability of anion-exchange membrane to chloride ions

A counter-current two-compartment dialyzer equipped with an anion-exchange membrane Neosepta-AFN was used to study dialysis of a hydrochloric acid and lithium chloride mixture. To quantify this process, several characteristics were calculated from the data obtained at steady state. First, the dialysis process was characterized by the acid recovery yield and rejection coefficient of salt, which were in the range of 61–98% and 62–94%, respectively (for HCl and LiCl concentrations from 0.1 to 1.0 kmol m−3 and volumetric liquid flow rates from 8 × 10−9 to 24 × 10−9 m3 s−1). Furthermore, this study proved that dialysis of an HCl + LiCl mixture can be quantified by a single characteristic, i.e., the permeability coefficient of the membrane to chloride ions, which is a function of the concentration of both the components in the feed.

The removal of chromium ions from water in Donnan dialysis process

The removal of chromium ions from water in Donnan dialysis process

A convenient method for isolating carbon quantum dots in high yield as an alternative to the dialysis process and the fabrication of a full-band UV blocking polymer film

A convenient method to isolate &gt;80% CQD and the fabrication of a non-toxic CQD polymer film which could protect UV-sensitive foods.

Collagen Binding Domain (CBD)과 융합된 재조합 Epidermal Growth Factor (EGF)의 과발현 및 가용화의 최적화

Previously, we constructed the recombinant plasmid which containing human epidermal growth factor and collagen binding domain for overproduction of fused biofunctional protein. However, this fusion protein was expressed in Escherichia coli as insoluble protein form in cytoplasm. Therefore, effective denaturation and dialysis process is critical for solubilization and refolding in protein purification process. We attempted several chemicals and buffer conditions for induction, dialysis, and solubilization. Using lactose instead of isopropyl β-D-1-thiogalactopyranoside, expression of target protein was induced. 20 mM tris-HCl buffer for dialysis was suitable for the activity and soluble form of fusion protein. Furthermore, for the solubility of expressed inclusion protein, we conducted with various pH conditions and concentrations of urea and guanidine hydrochloride. The efficient solubility of inclusion body form of fusion protein was showed at alkaline pH condition containing urea.

Zein self-assembly using the built-in ultrasonic dialysis process: microphase behavior and the effect of dialysate properties

The microphase behavior at different time scales was investigated to understand the mechanism of zein self-assembly during the built-in ultrasonic dialysis process (BUDP) in this study. The results indicated that the mutual mass transfer between zein solution and dialysate changed the solvent polarity, which caused the conformational transition of zein molecules, formation of stable droplets under the ultrasonic field, and further solidification of the compact microspheres. The effects of dialysate properties on zein self-assembly were investigated. The results showed that both pH and ionic strength had a great effect on the size, zeta potential, and morphology of the obtained zein particles, where zein microspheres with a size around 1–2 μm and zeta potential > 30 mV were obtained at pH 4–pH 8 and NaCl concentration ≤ 10 mM. And non-ionic Tween 60 could be used as a potential surfactant to improve the stability of zein samples through a physical combination.

A differential weak measurement system based on Sagnac interferometer for self-referencing biomolecule detection

A differential weak measurement system was presented, exhibiting the self-referencing function for biomolecule real time detection as a label-free optical biosensor. We built a Sagnac interferometer, which limited horizontal (H) and vertical (V) polarization to propagating along the common path but in opposite directions to realize weak measurements with two measuring channels installed in two corners of this Sagnac interferometer. By introducing two half wave plates into the system alternately with the two channels to convert between H and V polarization, we obtained a differential measurement for phase delay, which could quantitatively characterize the refractive index change corresponding to the concentration of samples in the channels. With this system, a real time monitor of molecule concentration in the dialysis process was accomplished, demonstrating the function of self-referencing, which is important for optical label-free molecule detection in a complex biological sample solution.

Autophagy promotes fibrosis and apoptosis in the peritoneum during long-term peritoneal dialysis.

Long‐term peritoneal dialysis is accompanied by functional and histopathological alterations in the peritoneal membrane. In the long process of peritoneal dialysis, high‐glucose peritoneal dialysis solution (HGPDS) will aggravate the peritoneal fibrosis, leading to decreased effectiveness of peritoneal dialysis and ultrafiltration failure. In this study, we found that the coincidence of elevated TGF‐β1 expression, autophagy, apoptosis and fibrosis in peritoneal membrane from patients with peritoneal dialysis. The peritoneal membranes from patients were performed with immunocytochemistry and transmission electron microscopy. Human peritoneal mesothelial cells were treated with 1.5%, 2.5% and 4.25% HGPDS for 24 hrs; Human peritoneal mesothelial cells pre‐treated with TGF‐β1 (10 ng/ml) or transfected with siRNA Beclin1 were treated with 4.25% HGPDS or vehicle for 24 hrs. We further detected the production of TGF‐β1, activation of TGF‐β1/Smad2/3 signalling, induction of autophagy, EMT, fibrosis and apoptosis. We also explored whether autophagy inhibition by siRNA targeting Beclin 1 reduces EMT, fibrosis and apoptosis in human peritoneal mesothelial cells. HGPDS increased TGF‐β1 production, activated TGF‐β1/Smad2/3 signalling and induced autophagy, fibrosis and apoptosis hallmarks in human peritoneal mesothelial cells; HGPDS‐induced Beclin 1‐dependent autophagy in human peritoneal mesothelial cells; Autophagy inhibition by siRNA Beclin 1 reduced EMT, fibrosis and apoptosis in human peritoneal mesothelial cells. Taken all together, these studies are expected to open a new avenue in the understanding of peritoneal fibrosis, which may guide us to explore the compounds targeting autophagy and achieve the therapeutic improvement of PD.