High Solute Concentrations Research Articles

Sosyoekonomik Durumun ve Tıbbi Tedavinin Uzun Dönemde Periton Diyaliz Hastalarında Mortalite Üzerine Etkisi: Retrospektif Kesitsel Araştırma

Objective: Despite technical advances in peritoneal dialysis (PD), mortality rates are still very high. Factors affecting mortality have been the aim of many studies. However, there are not enough studies investigating the effects of socio-economic status (SES) and medical treatments on mortality. The aim of our study is to investigate the long-term effects of SES and medical treatments on mortality in PD patients. Material and Methods: The study included 145 patients. Demographic characteristics, laboratory data, and medical treatments were recorded. Three main variables play a role in the SES indices. These variables are education, income level and occupation. These variables were questioned in PD patients. Cox regression analysis was used to determine the factors affecting mortality. Results: The mean age of the patients was 57.51±15.73 years, and 14% had a low income level. After 3.8±3.6 years of follow-up, 27.6% of the patients had died. The income level was lower, the tendency to infection was higher in the non-survivor group. There was no difference between survivor and non-survivor group in terms of gender, age, marital status, PD duration. Factors affecting mortality were low income [hazard ratio (HR): 2.272, 95% confidence interval (CI): 1.12-4.812, p=0.001], using high peritoneal dialysate glucose concentration solution, and low use of phosphorusbinding drugs and calcitriol (HR: 2.812, 95% CI: 1.160-6.818 and HR: 3.632, 95% CI: 1.665-7.291, p=0.001, respectively). Conclusion: Low income level in PD patients increases mortality by creating a tendency to infections. Lack of volume control and malnutrition are other factors affecting mortality.

Short and long-range cyclic patterns in flows of DNA solutions in microfluidic obstacle arrays.

We observe regular patterns emerging across multiple length scales with high-concentration DNA solutions in microfluidic pillar arrays at low Reynolds numbers and high Deborah numbers. Interacting vortices between pillars lead to long-range order in the form of large travelling waves consisting of DNA at high concentration and extension. Waves are formed in quadratic arrays of pillars, while randomizing the position of the pillar in each unit cell of a quadratic array leads to suppression of the long-range patterns. We find that concentrations exceeding the overlap concentration of the DNA enables the waves, and exploring the behavior of the waves as a function of flow rate, buffer composition, concentration and molecular length, we identify elastic effects as central to the origin of the waves. Our work may not only help increase the low throughput that often limits sample processing in microfluidics, it may also provide a platform for further studies of the underlying viscoelastic mechanisms.

Plasma‐activated ethanol solution and it's decontamination effect

AbstractEthanol solution as a disinfectant has been widely used in various fields. However, it has a significant bactericidal capability only when the volume fraction of ethanol is around 70%–75%. For such high concentration of ethanol solution, it has an irritating smell. When it is used for applications such as wound disinfection, it causes a stinging sensation. Low concentrations of ethanol solution are less irritating, but it is also less effective at killing bacteria. In this study, an idea for producing a green, efficient and less irritating disinfectant is proposed. It is based on a plasma‐activated low‐concentration ethanol solution (PAES). It is found that the plasma‐activated 10% volume fraction of ethanol solution can kill more than seven orders of magnitude of Escherichia coli, while the untreated 10% volume fraction of ethanol solution has no bactericidal effect. Besides, the PAES's activity remains unchanged after being stored at for three days. Further investigation shows that new compositions including peracetic acid, peroxynitrite, hydrogen peroxide and acetic acid are detected in the PAES, which together are playing the main role of the excellent and prolonged bactericidal effect.

Rheological and microstructural properties of polysaccharide obtained from the gelatinous Tremella fuciformis fungus

The gelatinous feature of Tremella fuciformis polysaccharide (TFP) has attracted growing interest in its application as a thickening agent in the food industry. This study aims to reveal the microstructure and rheological properties of TFP. Results showed that TFP randomly distributed in aqueous solutions in an irregular worm-like morphology and formed a more extensive entangled network and stiffer chains at higher concentration solutions. The further rheological study indicated that the TFP solutions exhibited a shear-thinning behavior. Multiple results of dynamic oscillation tests confirmed the viscoelastic properties of TFP. Frequency sweep data display that TFP solutions exhibit solid-like behavior at high frequencies, showing the oscillatory behavior of entangled polymers. The temperature sweep demonstrated that the rheological behavior of TFP is thermally reversible. These results enriched the understanding of the rheology-microstructure relationship of TFP solution and were beneficial to expanding the application of TFP in food processing.

Recent progress in the design of photocatalytic H2O2 synthesis system.

Photocatalytic synthesis of hydrogen peroxide under mild reaction conditions is a promising technology. This article will review the recent research progress in the design of photocatalytic H2O2 synthesis systems. A comprehensive discussion of the strategies that could solve two essential issues related to H2O2 synthesis. That is, how to improve the reaction kinetics of H2O2 formation via 2e- oxygen reduction reaction and inhibit the H2O2 decomposition through a variety of surface functionalization methods. The photocatalyst design and the reaction mechanism will be especially stressed in this work which will be concluded with an outlook to show the possible ways for synthesizing high-concentration H2O2 solution in the future.

High-performance porous copolymer hydrogel for oceanic electricity generation

Micro/nano fluidic electricity generation systems based on solid–liquid interface interaction to harvest energy from water in nature offer a potential green and clean electricity generation method. However, the performances of electricity generation were limited in salt solutions. In this paper, we prepared an extraordinary-performance hydrogel through ultraviolet polymerization for the access of ion concentration energy in seawater. This copolymer hydrogel made of AAm/AA (acrylamide/acrylic acid) provides a negatively charged three-dimensional transport network with micro/nano porous channels, which exhibits extraordinary ion selectivity in high ion concentration solutions. The experimental results show that this electricity generation device with intrinsic micro/nano pores can generate a continuous open-circuit voltage of 0.37 V, a short-circuit current of 116 μA, and a power density of 89.4 µW/cm2 from seawater (the Yellow Sea in China). The output current and power can be maximally more than 100 times and 50 times higher than the existing results. Through the series connection of six devices, the overall output is sufficient to supply stable power to directly light up small commercial electronic devices. Our study presents a new research idea for the development of low-cost, environmentally friendly, and self-powered devices.

The Effect of Terminal Bromoalkoxy Substituents on the Photochromism of Functionalized 2H‐Chromenes

AbstractA series of 2,2‐diphenyl‐2H‐chromene derivatives bearing electron‐donating groups at the benzopyran ring have been synthesized. A significant effect of the bromoalkoxy chain length and the concentration of chromenes on the conversion of closed (CF) into open forms under UV irradiation and the equilibrium between TC (transoid‐cis) and TT (transoid‐trans) isomers in the photostationary state was found. For chromene derivatives, a sequential (CF→TC→TT) or parallel (CF→TC; CF→TT) mechanism of transformation of the closed form into an open one is possible. A high solution concentration contributes to a significant shift of the photochromic equilibrium towards the TT isomer. The proposed scheme of the ring‐opening reaction was confirmed by the analysis of the NMR spectra of acetonitrile solutions of chromene derivatives obtained by gradual irradiation. The results obtained are important for a deeper understanding of the nature of photochromic reactions.

Experimental study on the effects of salt solution pH on the performance of reverse electrodialysis stack

Reverse electrodialysis (RED) is a promising way of harvesting salinity gradient energy (SGE). The seawater or industrial wastewater may have various pHs. Here the RED performance involving sodium salt solutions with different ion valence ratios including anions of Cl-, SO42-, and PO43- is experimentally investigated in symmetric and asymmetric pH configurations. In the symmetrical pH configuration, increasing the solution pH significantly weakens the energy conversion performance for the 1:1 and 1:3 salts; for the 1:2 salt, the power density and energy conversion efficiency increase and then decrease with increasing pH due to the coupling effects of OH- on the ion transportation through AEMs and CEMs. In the asymmetric pH configuration, increasing the pH of the low concentration solution decreases the power density and energy conversion efficiency. As the pH of the high concentration solution increases, the output power and energy conversion efficiency decrease and then increase for the 1:1 salt due to the coupling effects of the ion transmembrane concentration difference and OH- on the ion migration of IEMs; for the 1:2 salt, the output power and energy conversion efficiency increase and then decrease; for the 1:3 salt, OH- inhibits the hydrolysis of Na3PO4 and anion migration, leading to the lowered output power density and energy efficiency.

Evaluation of Commercial Reverse Osmosis and Nanofiltration Membranes for the Removal of Heavy Metals from Surface Water in the Democratic Republic of Congo

This study evaluates the performance of commercial reverse osmosis (RO) and nanofiltration (NF) membranes for the removal of metal ions from synthetic water and surface water carried from the north-west of Lake Tanganyika in the city of Uvira, in the east of the Democratic Republic of Congo. Metal ion analyses were performed by the standardized ICP-MS and ICP-OES methods. The RO membrane showed higher metal ion rejection in high-concentration solutions (synthetic samples) prepared in the laboratory as well as in low-concentration samples from real raw water collected near Lake Tanganyika. Rejection levels were higher than 98% for Cr3+, Pb2+, Cd2+, As3+, Ni2+, and Sb+3 ions in the synthetic solutions, and 99.2, 98.8, 98.6, 99.2, 98.4, and 98.8%, respectively, in the real samples. The concentrations of metals in the permeate varied depending on the feed concentration and were 0.15 to 1.02 mg/L, 0.33 to 22 mg/L, and 0.11 to 22 mg/L in RO, NF90, and NF270 membranes, respectively. Regarding the NF membranes, the rejection of Cr, Ni, and Cd ions was interesting: 98.2, 97.8, and 92.3%, respectively. However, it was lower for Pb, As, and Sb ions: 76.9, 52.5 and 64.1%, respectively. The flux of NF was 329 to 375 L/m2.h, much higher than for RO membranes, which had a flux of 98 to 132 L/m2.h. The studied membranes are thus a feasible solution to remove the studied metals from real water sources at low concentrations since they meet the standards of the World Health Organization on specific values assigned to chemicals from industrial sources and human habitation areas where these ions are present in drinking water.

Prolotherapy with Very Fine Needle and Low Concentration of Glucose in a Patient with Chronic Lateral Elbow Pain

Prolotherapy is a non-surgical injection treatment method that repeatedly injects small amounts of proliferators into damaged ligaments, tendon, joints and surrounding tissues. The most common proliferator is a high concentration of glucose solution. Glucose solutions with a concentration of 10-25% are commonly used. Prolotherapy using glucose solution has few serious adverse events, but common side effects include post injection pain, stiffness, edema, and mild bleeding. There are many cases of complaining of pain caused by injection during or after prolotherapy. Some patients give up treatment if the pain is severe. A 43-year-old male patient visited the hospital with both elbow pain and left wrist pain, and prolotherapy was performed. In order to minimize pain during procedure and post injection pain of the patient, 10% glucose solution with 0.5% lidocaine was injected using a very fine needle of 30 G. The total number of treatments was eight. The patient did not complain of pain caused by needle insertion during procedure and post-injection pain. Chronic pain that lasted for two years after treatment almost disappeared. The patient was very satisfied with this treatment method and result.

Staining of stratum corneum with fluorescent ε-poly-L-lysine and its application to evaluation of skin conditions.

ε-Poly-L-lysine (PLL) is a cationic polymer consisting of 25 to 35 L-lysine residues that adheres to the surface of skin as well as hair. However, the properties of PLL regarding its adhesion to the skin remain to be elucidated. In this study, we examined the staining of stratum corneum (SC) with fluorescence-labeled PLL and explored its relationship with skin condition. Alexa Fluor 488-labeled PLL (AF-PLL) was reacted with tape-stripped stratum corneum (SC), and the staining properties were monitored by fluorescence microscopy. Clinical study was performed by measuring the water content of the cheek SC and transepidermal water loss (TEWL), and the tape-stripped SC was subjected to staining with AF-PLL. AF-PLL staining of the SC was inhibited at acidic pH or by the addition of high concentration of salt solution, suggesting the involvement of ionic interaction between PLL and the SC, at least in part. The AF-PLL staining was inhibited by unlabeled PLL or various alkyl amines, but not by L-lysine monomer. AF-PLL staining was observed inside the corneocytes as well as surrounding cornified envelope. Clinical study revealed that AF-PLL staining intensity of the SC was negatively correlated with its water content and positively correlated with its TEWL. PLL can efficiently adhere to SC and AF-PLL staining of SC can be applied to evaluate skin conditions.

Efficient Removal of High-Concentration Dye Pollutants in Wastewater Using Composite Photocatalyst NH2-MIL-125 (Ti)/g-C3N4 Nanosheets Under Visible Light

The NH2-MIL-125(Ti)/g-C3N4 nanosheets composite photocatalyst was prepared by one-step solvothermal synthesis and used to remove high-concentration dye wastewater. The morphology, structure, and photoelectrochemical properties of the as-synthesized samples were characterized by XRD, SEM, XPS, FT-IR, UV–vis DRS PL, EIS, and transient photocurrent. The results showed that g-C3N4 nanosheets were tightly loaded on the surface of NH2-MIL-125(Ti) to form the NH2-MIL-125(Ti)/g-C3N4 nanosheets composite photocatalyst. Among them, NM (Ti)/CNNS30 showed the best adsorption performance and photocatalytic degradation activity for removing high-concentration RhB solution. In addition, the optimal experimental conditions were also explored, such as the concentration of RhB solution, the dosage of NM (Ti)/CNNS30, and the initial pH of RhB. Finally, the mechanism of photocatalytic degradation of NM(Ti)/CNNS30 on high-concentration RhB solution was also proposed based on active species capture experiment and energy band structure analysis. It was inferred that O2− and h+ were the main active species for NM(Ti) photocatalytic degradation of high-concentration RhB. This work provided new insights into the design and synthesis of highly efficient photocatalysts for the practical treatment of high-concentration dye wastewater.

Benchmark Al-Cu Solidification Experiments in Microgravity and on Earth

Predicting macrosegregation and grain structure, including the columnar to equiaxed transition (CET), in alloy solidification is an ongoing challenge. Gravity-driven melt convection and transport of unattached solid grains complicate such efforts. Cylindrical samples of aluminum alloys containing 4, 10, and 18 wt pct copper are solidified from the bottom upwards on Earth and in microgravity conditions aboard the International Space Station. The chosen alloys possess primary solid densities that are greater than, equal to, and less than their melt densities promoting different gravity-driven solid transport phenomena. Significant differences in grain structure are observed between microgravity and terrestrial samples. All microgravity samples are entirely equiaxed, while the terrestrial samples exhibit a CET. The columnar grains near the cooled surface in the terrestrial samples can only be attributed to melt convection. The Al-4 wt pct Cu terrestrial sample shows evidence of grain sedimentation, while the Al-18 wt pct Cu terrestrial sample exhibits the effects of grain floatation. Measurements of eutectic fraction and solute concentration in the samples show inverse segregation due to shrinkage-driven flow in all samples. Terrestrially solidified samples have areas of high solute concentration that are not uniformly distributed over the diameter, indicating the presence of melt convection. The eutectic and macrosegregation measurements generally have good correspondence. Temperature, grain structure, eutectic fraction, and macrosegregation data are presented as benchmark data to validate future modeling efforts. Heat flux boundary conditions on the sample are determined using thermal modeling. Thermal process parameters are calculated for all samples.

Enhancement of In Vitro Bioactivity of One-Step Spark Plasma Sintered Porous Titanium by Alkali-Treatment

Bioactivity and stress shielding are the most important problems of medical implanted porous titanium. In this study, porous titanium with 40% porosity was prepared by one-step spark plasma sintered (SPS) technology, and the surface of porous titanium was modified by a simplified alkali treatment method. The effects of a high concentration on pore properties, mechanical properties, and biological activities of porous titanium were investigated. The results show that the surface of porous titanium treated with a high concentration of alkali forms an interconnected network layer, which provides nucleation points for the formation of apatite. Porous titanium can still meet the requirements of hard tissue replacement after treatment with high-concentration alkali solution (yield strength (130 MPa) and elastic modulus (6.0 GPa)). A layer of apatite is formed on the surface of porous titanium after alkali treatment. The ability of inducing apatite formation increases with the increase of lye concentration. In addition, the results of proliferation and live dead cell staining of bone mesenchymal stem cells (BMSC) showed that alkali treatment had no toxic effect on the cells. With the increase of concentration, the cell activity was significantly enhanced. Therefore, the bioactive porous titanium modified with simplified alkali has a good medical prospect as artificial bone material.

Internal interaction between chemically-pretreated polypropylene microplastics and floc growth during flocculation: Critical effect on floc properties and flocculation mechanisms

Microplastic pollution in drinking water resources has attracted increasing concerns due to the potential harm of microplastic particles to the health of either human or other living creatures. To better understand how the presence of microplastic contaminants would affect floc morphological properties and associated flocculation mechanism, various chemically-pretreated polypropylene (PP) microplastics were firstly produced by exposing pristine ones to HCl or NaOH solution at two concentrations of 1 and 5 mol/L. SEM and FTIR analyses demonstrated that microplastic physicochemical properties (including surface morphological details and oxygen-containing functional groups) were related to the type and concentration of chemical reagent for pretreatment. When flocculating model PP-containing water samples with coagulant of polymeric ferric sulfate (PFS), the involvement of PP microplastics after NaOH-based pretreatment was found more beneficial for the formation of larger floc aggregates during flocculation than those after HCl-based pretreatment at a fixed chemical-reagent concentration, whereas for either chemical pretreatment, PP microplastics produced at a higher solution concentration seemed to facilitate the process of larger PP-containing floc growth. Also, the structure, strength and recovery ability of resultant floc aggregates at steady state of flocculation appeared quite different, possibly attributed to distinct interaction patterns between preformed floc aggregates and microplastic particles, under all circumstances of chemically-pretreated PP microplastics investigated. Furthermore, it was suggested that the growth of PP-containing flocs during flocculation was partially determined by not only charge neutralization, but also the incorporation of humic acid (HA) molecules into PP-containing floc aggregates via the formation of PFS-HA and/or PFS-HA-PP complexes.

Adsorption and electro-assisted method removal of boron in aqueous solution by nickel hydroxide

Technical research on electrochemical acid-free desorption of boron is imminent, and layered nickel hydroxide is a potential boron-responsive active electrode material. In this paper, nickel hydroxide was used to remove boron from aqueous resources by electro-assisted and conventional adsorption methods. The option of conditions by nickel hydroxide adsorption for boron is mild (pH: 7 ∼ 9) with an exothermic process. Interestingly, the synergistic effect of physical and chemical adsorption improves the adsorption rate and adsorption capacity of nickel hydroxide for boron under the action of the electric field, and the adsorption performance is better at low voltage (0.2 ∼ 0.4 V). The equilibrium time of the electro-assisted method is 4 times shorter than conventional adsorption methods, and the maximum adsorption capacity can reach 57.5 mg/g than conventional adsorption (45.4 mg/g). In addition, the nickel hydroxide has selectivity in high-concentration anion solutions and can be easily regenerated by an alkaline solution. Therefore, it is expected that nickel hydroxide with the electro-assisted method could be a potential approach for the high-efficiency and eco-friendly removal of boron.

Removal of phosphates using eggshells and calcined eggshells in high phosphate solutions

This study was conducted to evaluate the phosphate sorption properties of eggshell (ES) and calcined ESs (C-ESs) in a high-concentration phosphate solution. The C-ESs yield decreased rapidly at 900 °C, indicating that the CaCO3 constituting the ES was converted to CaO by the high calcination temperature. The optimum calcination temperature for phosphate removal using C-ES was 900 °C. The actual sorption amount of phosphate by ES and C-ES900 was in agreement with the Langmuir isothermal sorption equation, and the maximum sorption capacities derived from this equation were 178.6 and 270.3 mg/g, respectively. The sorption rate of phosphate by ES and C-ES900 was divided into two stages: an initial fast sorption stage, followed by a slow sorption stage. The sorption of phosphate by ES was dominantly influenced by the initial pH and salt concentration, whereas C-ES900 exhibited a constant sorption capacity regardless of environmental changes. The SEM–EDS and XRD results demonstrated that phosphate was successfully adsorbed on the ES and C-SE900 surfaces. In this study, it was found that the sorption of phosphate by ES occurred via ion exchange and precipitation reactions and that the sorption of phosphate by C-ES900 was dominantly affected by precipitation. Above all, C-ES can be applied as an effective adsorbent for removing high concentrations of phosphate under a wide range of environmental conditions.

Hierarchical composite structure to simultaneously realize superior superhydrophobicity and anti-reflection

Superhydrophobicity and anti-reflection of metallic surfaces have potential applications, and obtaining superhydrophobicity on metallic surfaces by simple methods is still a challenge. The composite microstructure consisting of micro-protrusions, micro-lumps and particles was fabricated on aluminum surface by laser ablation. A layer of hydrophobic species that can prevent the surface from being wetted formed on the microstructure through organic adsorption. In particular, laser ablation parameters were optimized to achieve better superhydrophobicity and anti-reflection. The fabricated superhydrophobic surfaces showed contact angles > 165° for water and contact angles > 160° for high-concentration solutions and high-viscosity solutions. Conventional bounce contact time < 10 ms was exhibited for water droplets impacting on fabricated surfaces, especially, the shortest contact time reaching 9.4 ms. anti-reflection was also realized on the laser-ablated aluminum surface, and specular reflections were almost completely avoided by laser ablation structures. The mechanism of the transition from superhydrophilic to superhydrophobic on fabricated surfaces was discussed. Superhydrophobic aluminum surfaces with anti-reflection could be efficiently manufactured in a few hours without special equipment and harsh condition through the proposed two-step method.

High Molecular Weight AB-Polybenzimidazole and Its Solutions in a Complex Organic Solvent: Dissolution Kinetics and Rheology.

AB-polybenzimidazole (ABPBI) dissolution kinetics in an eco-friendly complex acid-free solvent based on dimethyl sulfoxide (DMSO), methanol and KOH, and the rheological behavior of their solutions are investigated. The optimal component ratio of solvent providing the complete ABPBI dissolution is determined. Methanol containing dissolved KOH contributes to the creation of a single-phase superbasic medium, which accelerates and improves the polymer solubility in a mixture with DMSO, significantly reducing the viscoelasticity of the resulting solution. The optimum methanol content is up to 60 wt.% related to DMSO. The polymer dissolution rate increases by 5 times in this composition. It found the polymer concentration of 9% is close to the dissolution limit due to the strong solution structuring, which is probably associated with an increase in the amount of water released during the KOH-methanol-DMSO interactions. As a result, the conditions for obtaining high concentrated solutions in a complex, mainly organic solvent for fiber spinning are developed. The viscoelastic properties of solutions are measured in the concentration range of 1-9% at temperatures of 20-50 °C. The flow activation energy for 7 and 9% solutions decreases by 1.5 and 2.3 times, respectively, as the content of methanol in the complex solvent increases from 10 to 60%.

INCREASING EFFICIENCY OF THE DISPLACEMENT OF HIGHLY RESINOUS OILS BY POLYMER SOLUTIONS

The article presents the experimental results of studies of the filtration properties of oils from fields with a high content of asphaltene-resinous substances. Experimental studies of the filtration process of deposits with a high content of asphaltene-resinous substances have established that in low-permeability, unlike high-permeability reservoirs, the beginning of filtration proceeds according to a nonlinear law, and with an increase in the pressure gradient, the nonlinearity turns into a straight line corresponding to the Darcy law. In addition, the results of experimental studies on the displacement of oil from fields with a high content of asphaltene-resinous substances by polymer solutions on artificially created reservoir models are presented to determine the concentration of the polymer solution and the size of the slug to increase oil recovery from reservoirs. Experimental research on oil displacement by polymeric solutions were carried out on reservoir models filled with quartz sand, while the analyzed deposits are represented by carbonate limestone rocks. The results obtained on the oil displacement by polymer solutions on reservoir models with terrigenous reservoirs are considered possible for use on objects with carbonate reservoirs with a qualitative justification for the introduction of the polymer flooding method. Experimental studies on the oil displacement from fields with a high content of asphalteneresinous substances with a thickened water rim have established that this method gives the greatest increase in anhydrous and ultimate oil recovery, within a change in the concentration of the polymer solution of 0.2-0.4%, with a rim size of more than 70% of the oil-saturated reservoir volume. Studies on the displacement of high-viscosity oils with polymer solutions have shown that the use of this method of increasing the oil recovery factor in practice is not always economically feasible, due to the need to provide high injection pressures and a high concentration of an expensive polymer solution.