Dimethyl Sulfone Research Articles

Direct catalytic olefination of alcohols with sulfones.

The synthesis of terminal, as well as internal, olefins was achieved by the one-step olefination of alcohols with sulfones catalyzed by a ruthenium pincer complex. Furthermore, performing the reaction with dimethyl sulfone under mild hydrogen pressure provides a direct route for the replacement of alcohol hydroxy groups by methyl groups in one step.

Direct Catalytic Olefination of Alcohols with Sulfones

AbstractThe synthesis of terminal, as well as internal, olefins was achieved by the one‐step olefination of alcohols with sulfones catalyzed by a ruthenium pincer complex. Furthermore, performing the reaction with dimethyl sulfone under mild hydrogen pressure provides a direct route for the replacement of alcohol hydroxy groups by methyl groups in one step.

Cold pressed poppy seed oils: sensory properties, aromatic profiles and consumer preferences

The sensory descriptions, aromatic profiles and consumer preferences of poppy seed oils produced from three poppy varieties (ofis3, ofis4, and ofis8) by cold pressing were studied. Roasting and enzyme treatments were applied to the seeds prior to cold pressing. In addition, 75 different volatiles were quantified by GC-MS analysis. A flavor profile analysis was made with 9 panelists and 12 terms were identified for the description of the oil. The results shown that, only earthy term scores were different among the seed varieties, while treatments have caused differences in roasted, hazelnut, hay and sweet aromatic terms. Roasting and enzyme treatments decreased hay and increased sweet aromatic values. The enzyme treatment of the poppy seeds enhanced fermented and waxy scores in the cold press oils. 1-hexanol, 2-heptanone, 2-pentanone, 2-pentyl furan, 3-ethyl- 2-methyl 1,3-hexadiene, 2-(dimethylamino)-3-phenylbenzo[b]thiophene, 3-octen-2-one, 4-hydroxyphenylacetic acid, alpha-pinene, limonene, dimethyl sulfone, mercaptoacetic acid, hexanal and nonanal were quantified as the major volatiles in all treatment groups. Consumer test results indicated that roasted samples are more liked, and the yellow (ofis4) roasted sample was identified as the most preferred (53.55%) oil by consumers. This study provides the first sensory descriptive definitions and consumer preferences for poppy seed oils.

On the structure of [Al(DMSO2)3]3+

Abstract The most stable [Al(DMSO2)3]3+ complex cation in dimethyl sulfone (DMSO2, (CH3)2SO2) has D3 symmetry with twofold axes in Al-S lines coincident with the twofold rotation axes of mutually turned DMSO2 ligands by ca 60°. The central Al atom is hexacoordinated by six O atoms with nearly octahedral coordination. More than one electron is transferred to the Al central atom from DMSO2 ligands. Weaker and longer S-O, stronger and shorter S-C bonds, lower O-S-O bond angles and greater O-S-C and C-S-C ones in [Al(DMSO2)3]3+ than in free DMSO2 are implied by weak Al-O bonding.

Al-Zn Alloy Formation from Non-Aqueous Solution By Electrochemical Technique

Introduction At present, the hot dipping of Zn-Al, uses to suppress the corrosion of the steel. In addition, Al-Zn alloy become a high strength material such as duralumin by making the alloying with Mg and Cu. An aluminum, that is less noble than hydrogen is, not able to be electrodeposited from aqueous solution.1)Therefore, the electrodepositions using ionic liquids or non-aqueous have been studied. However solution such as toluene, which has a risk of causing a spontaneous combustion because of it’s high flammable. An ionic liquids are salts whose melting point less than 100 ℃. Since the solution has very high electrical conductivity, high stability and, low volatility, it is suitable for plating solvent. In this study, we report on the results of the plating of the Al-Zn alloy films from the plating bath with AlCl3, ZnCl2 and dimethyl sulfone (DMSO2). Experiment The plating solution was composed of AlCl3, ZnCl2 and DMSO2. The total metal chloride ratio, (AlCl3 + ZnCl2) / (DMSO2 + AlCl3 + ZnCl2), is constant at 33.3 mol%. The ratio of ZnCl2 to AlCl3 is controlled from 0.005 to 1.0 mol%. A current density is 600A/m2. The acid activating (RT, 1min) after alkaline degreasing (60 ℃, 5min) is performed as pretreatment process. The plating was performed at 150 ℃ for 30 minutes. As analysis method of sample, we used X-ray diffraction (XRD), energy dispersive x-ray spectrometry (EDS), X-ray photoelectron spectroscopy (XPS). Results and Discussion Effect of bath composition As a result of changing the bath composition, metallic gloss plating film was deposited up to 0.05 molar percent metal salt concentration of Zn. The gray film was obtained in 1.0 molar percent.Results of by EDS The composition of the deposited Al-Zn alloy plating films was estimated by using EDS. The content of Zn is increased with increasing the concentration of the metal salt Zn. Result by X-ray diffraction (XRD) Figure 1 shows an XRD pattern of the sample. The peak of the Al can observed without the sample of 0.1 molar percent of Zn salt. Figure 2 shows an enlarged view of Al (200) peak area. With increasing of the Zn metal salt concentration, the diffraction peak is shifted to a lower angle side, and the half width is increased. An atomic radius of Zn and Al are 125 and 135 pm, respectively. The diffraction peak will be shifted to high angle in accordance with Vegard’s low, when Zn is replaced by Al site. The increase of half width shows deterioration of crystallinity. Acknowledgements This work was partially aided by MEXT-supported Program for the Strategic Research Foundation at Private Universities. References T. Hirato, J. Fransaer, and J. P. Celis, J. Electrochem.Soc., 148, C280 (2001).

Al-Fe Alloy Formation from Non-Aqueous Solution By Electrochemical Technique

Introduction The physical property of Fe x Al1-x is not only scientific but also technological interest because of its wide variety of potential applications. However, aluminum, that is less noble than hydrogen, is not be electrodeposited from aqueous solution. Therefore, the possibility of forming an aluminum film using an organic solvent, molten salts or ionic liquid has been studied. A dimethyl sulfone (DMSO2) is one of the most promising candidates for non-aqueous solvent.2. Experiment The plating solution was composed of AlCl３, FeCl3 and DMSO2. The total metal chloride ratio, (AlCl3 + FeCl3) / (DMSO2 + AlCl3 + FeCl3), is constant at 33.3 mol%. The ratio of FeCl3 to AlCl3 is controlled from 10 to 30 mol%. A current density is controlled from 300 to 1000 A/m2. Since a melting point of dimethyl sulfone is from to 109 oC, a plating temperature is necessary to be higher than this value. However, the aluminum plating was not sometimes performed at the temperature lower than 130 oC Results of thermal desorption spectrometry (TDS) showed that the desorption peaks of H2O appeared at 110 and 150 oC. This result suggests that the water in the solution inhibits the aluminum plating. For this reason, the following plating was performed at about 180 oC to dehydrate. The depositions were performed in a dry glove box filled with flowing dry nitrogen. Film thickness is controlled by the deposition time. The composition of the samples was estimated using a energy dispersive X-ray spectrometry microscope (EDS, JEOL JSM-6000). The X-ray photoelectron spectroscopy (XPS) results were obtained by a Kratos Analytical AXIS ULTRA DLD equipped with an Al Kα X-ray source (hν = 1486.6 eV, 10.0 mA, 15 kV). The binding energies were calibrated with the C 1s peak at 284.8 eV.3. Results and Discussion The atomic composition of the samples was determined by EDS. Figure 1 shows the effect of different FeCl3 ratio on the Fe ratio in the films. The Fe ratio is increased with increasing the FeCl3 ratio and reached almost 100 mol% at 20 mol% FeCl3. The FeCl3 ratio dependence of the Fe ratio is changed in the same manner at both 600 and 1000 A/m2 of the current density. The plating films have a low Fe concentration at high current density electrodeposition, because Fe is more noble than Al. The peak intensity ratio for Fe 3p / Al 2p estimated from XPS measurements is increased with increasing in FeCl3 ratio. This result is consistent with the result of EDS.4. Conclusion Electrodeposition of Al-Fe alloy from the AlCl3 -DMSO2 plating solution with FeCl3 was investigated. The total metal chloride ratio is constant at 33.3 mol%. The ratio of FeCl3 to AlCl3 is controlled from 10 to 30 mol%. A current density is controlled from 300 to 1000 A/m2. Fe content is controllable from 0 % to almost 100 %. The significant morphological changes to the films were appeared by the addition of FeCl3 to the plating solution.5. Acknowledgement This work was partially aided by MEXT-supported Program for the Strategic Research Foundation at Private Universities.

Chemical Composition and Aroma Evaluation of Essential Oils from Evolvulus alsinoides L.

The aim of this study was to investigate the chemical composition and the odor-active compounds of the essential oils from Evolvulus alsinoides, which is a well-known edible and medicinal plant. The volatile compounds in the oils were identified by hydrodistillation (HD) and solvent-assisted flavor evaporation (SAFE) in combination with GC, GC/MS, GC/O (=olfactometry), aroma extract dilution analysis (AEDA), and relative flavor activities (RFA values). The most abundant compound in the HD oil was cis-α-necrodol (12.62%), an irregular monoterpene with a cyclopentane skeleton, which is very unusual in the plant kingdom. In the SAFE oil, the main components included 2-butoxyethanol (9.01%), benzyl alcohol (8.01%), and γ-butyrolactone (7.37%). Through sensory analysis, 21 aroma-active compounds were identified by GC/O. The most intense aroma-active compounds in the HD oil were hexan-1-ol and γ-nonalactone, both of which showed high RFA values. α-Methyl-γ-butyrolactone and dimethyl sulfone contributed more strongly to the aroma of the SAFE oil. These results imply that the essential oils of E. alsinoides deserve further investigation in the food industry.

Use of Dimethyl Sulfone as Additive in Aprotic Electrolytes

The aim of this work is to determination the influence of dimethyl sulfone on electrical properties of electrolytes. Dimethyl sulfone is an adjacent product by many chemical manufactories. The key thought of this article is to find a possibility to use of this adjacent product. In this work is dimethyl sulfone used as additive into commonly applied solvents that are used for aprotic electrolytes. There will be established properties in low flammable solvent such as sulfolane too. The article will discussed specific conductivity of this solvents mixtures.

Volatile sulfur compounds in pasteurised and UHT milk during storage

Cooked or sulfurous off-flavour caused by volatile sulfur compounds (VSCs) limits acceptance of ultra-high temperature (UHT) milk in some parts of the world. Therefore, the concentrations of VSCs in UHT milk over 16 weeks of storage were studied and compared with those in pasteurised milk. The major VSCs contributing to the cooked flavour were identified using solid-phase microextraction and gas chromatography with pulsed flame photometric detection. Nine VSCs were detected in commercial indirectly processed UHT skim and whole milk. These were hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide, carbon disulfide, dimethyl disulfide, dimethyl sulfoxide, dimethyl sulfone and dimethyl trisulfide. An additional VSC was detected but not identified. The concentrations of hydrogen sulfide, methanthiol, dimethyl sulfide and dimethyl trisulfide were initially higher than their reported threshold values indicating their importance in milk flavour, especially cooked flavour. However, they decreased slowly during storage to levels below their threshold values. This decrease corresponded to a decrease in dissolved oxygen level. Four VSCs, carbon disulfide, dimethyl sulfide, dimethyl sulfoxide and dimethyl disulfide, were detected in pasteurised milk; however, their concentrations were lower than their reported threshold values. This paper puts into perspective the significance of VSCs in the flavour of UHT and pasteurised milk, both initially and during storage, and indicates the period of storage for minimisation of cooked flavour in UHT milk.

Rheological Properties of Solvents for Electrolytes of Lithium – Ion Batteries

The article deals with description of rheological properties of solvents for electrolytes of lithium-ion accumulators. Solvents mixture of dimethyl sulfone and sulfolane at different volume ratios and with a lithium salt (LiClO4) appear as potentially suitable electrolyte. The aim of this experiment is to investigate the rheological properties, particularly density and dynamic viscosity, of solvents with lithium salt in temperature dependence and to find the optimal composition of the electrolyte from the perspective of achieving the lowest dynamic viscosity and better electrical conductivity because both quantities are closely related in accordance with Walden’s rule. The vibration method is used to determine the values of dynamic viscosity.

Density Functional Theory Study on Structural and Energetic Characteristics of Graphite Intercalation Compounds

The structures and energetics of a number of graphite intercalation compounds (GICs) having a relatively wide range of chemistry have been investigated by density functional theory calculations with the van der Waals correction using the dispersion correction method within the framework of generalized gradient approximation. The GICs studied included potassium-intercalated graphite (KCn), lithium-intercalated graphite (LiCn), lithium solvated by dimethyl sulfone (DMSO)-intercalated graphite (Li(DMSO)4Cn), lithium solvated by dibuthoxy ethane (DBE)-intercalated graphite (Li(DBE)2Cn), perchlorate (ClO4)-intercalated graphite (ClO4Cn), and hexafluorophosphate (PF6)-intercalated graphite (PF6Cn). Our calculations show reasonable agreement with experimental data for the interlayer distances of the GICs. A correlation between the size of the intercalate and the interlayer distance of the GIC has been observed. Our study has also predicted that all the GICs studied here are energetically stable except for Li(DBE)2Cn, consistent with experimental observations. Our results have suggested that there is a strong correlation between the intercalation energy and the electron transfer between the intercalate and graphite. On the basis of our results, we propose that the ionization potential or the electron affinity of the intercalate, along with the size of the intercalate, is a good measure for the stability of the resulting GIC in general.

Serum and urine metabolomic fingerprinting in diagnostics of inflammatory bowel diseases

To evaluate the utility of serum and urine metabolomic analysis in diagnosing and monitoring of inflammatory bowel diseases (IBD). Serum and urine samples were collected from 24 patients with ulcerative colitis (UC), 19 patients with the Crohn's disease (CD) and 17 healthy controls. The activity of UC was assessed with the Simple Clinical Colitis Activity Index, while the activity of CD was determined using the Harvey-Bradshaw Index. The analysis of serum and urine samples was performed using proton nuclear magnetic resonance (NMR) spectroscopy. All spectra were exported to Matlab for preprocessing which resulted in two data matrixes for serum and urine. Prior to the chemometric analysis, both data sets were unit variance scaled. The differences in metabolite fingerprints were assessed using partial least-squares-discriminant analysis (PLS-DA). Receiver operating characteristic curves and area under curves were used to evaluate the quality and prediction performance of the obtained PLS-DA models. Metabolites responsible for separation in models were tested using STATISTICA 10 with the Mann-Whitney-Wilcoxon test and the Student's t test (α = 0.05). The comparison between the group of patients with active IBD and the group with IBD in remission provided good PLS-DA models (P value 0.002 for serum and 0.003 for urine). The metabolites that allowed to distinguish these groups were: N-acetylated compounds and phenylalanine (up-regulated in serum), low-density lipoproteins and very low-density lipoproteins (decreased in serum) as well as glycine (increased in urine) and acetoacetate (decreased in urine). The significant differences in metabolomic profiles were also found between the group of patients with active IBD and healthy control subjects providing the PLS-DA models with a very good separation (P value < 0.001 for serum and 0.003 for urine). The metabolites that were found to be the strongest biomarkers included in this case: leucine, isoleucine, 3-hydroxybutyric acid, N-acetylated compounds, acetoacetate, glycine, phenylalanine and lactate (increased in serum), creatine, dimethyl sulfone, histidine, choline and its derivatives (decreased in serum), as well as citrate, hippurate, trigonelline, taurine, succinate and 2-hydroxyisobutyrate (decreased in urine). No clear separation in PLS-DA models was found between CD and UC patients based on the analysis of serum and urine samples, although one metabolite (formate) in univariate statistical analysis was significantly lower in serum of patients with active CD, and two metabolites (alanine and N-acetylated compounds) were significantly higher in serum of patients with CD when comparing jointly patients in the remission and active phase of the diseases. Contrary to the results obtained from the serum samples, the analysis of urine samples allowed to distinguish patients with IBD in remission from healthy control subjects. The metabolites of importance included in this case up-regulated acetoacetate and down-regulated citrate, hippurate, taurine, succinate, glycine, alanine and formate. NMR-based metabolomic fingerprinting of serum and urine has the potential to be a useful tool in distinguishing patients with active IBD from those in remission.

Initial Concentration Dependence of Dimethyl Sulfoxide Oxidation by Pulsed Discharge Plasma in Air with Water Droplets Spray

AbstractInitial concentration dependence of dimethyl sulfoxide (DMSO) oxidation has been investigated by pulsed discharge plasma in air with water droplets spray for the first time. Dimethyl sulfone (DMSO

A non-invasive method for in vivo skin volatile compounds sampling

The use of volatile organic compounds (VOCs) emanating from human skin presents great potential for skin disease diagnosis. These compounds are emitted at very low concentrations. Thus, the sampling preparation step needs to be implemented before gas chromatography–mass spectrometry (GC–MS) analysis. In this work, a simple, non-invasive headspace sampling method for volatile compounds emanating from human skin is presented, using thin film as the extraction phase format.The proposed method was evaluated in terms of reproducibility, membrane size, extraction mode and storage conditions. First, the in vial sampling showed an intra- and inter-membrane RSD% less than 9.8% and 8.2%, respectively, which demonstrated that this home-made skin volatiles sampling device was highly reproducible with regard to intra-, inter-membrane sampling. The in vivo sampling was influenced not only by the skin metabolic status, but also by environmental conditions. The developed sampling set-up (or “membrane sandwich”) was used to compare two different modes of sampling: headspace and direct sampling. Results demonstrated that headspace sampling had significantly reduced background signal intensity, indicating minimized contamination from the skin surface. In addition, membrane storage conditions both before and after sampling were fully investigated. Membranes stored in dry ice for up to 72h after collection were tested and showed no or minimal change in volatile profiles.This novel skin volatile compounds sampling approach coupled with gas chromatography–mass spectrometry (GC–MS) can achieve reproducible analysis. This technique was applied to identify the biomarkers of garlic intake and alcohol ingestion. Dimethyl sulphone, allyl methyl sulfide and allyl mercaptan, as metabolites of garlic intake, were detected. In addition, alcohol released from skin was also detected using our “membrane-sandwich” sampling. Using the same approach, we analyzed skin VOCs from upper back, forearm and back thigh regions of the body. Our results show that different body locations share a number of common compounds (27/99). The area with most compounds detected was the upper back skin region, where the density of sebaceous glands is the highest.

Effect of transient receptor potential A1 antagonists on post-operation pain in a rat model of incisional pain

Objective To investigate the effect of intrathecal and intraplantar injection of transient receptor potential A1 (TRPA1) antagonists on post-operation pain in a rat model of incisional pain.Methods Seventy-two adult male Sprague-Dawley rats weighing 200-250 g were randomly divided into 6 groups (n =12):control group (group C),incision group (Ⅰ group).intrathecal injection of DMSO group (DMSO1 group),intraplantar injection of DMSO group (DMSO2 group),intrathecal injection of HC-030031 group (H1 group),intraplantar injection of HC-030031 group (H2 group).Rats in Ⅰ,DMSO1,DMSO2,H1,and H2 groups were operated with incision.Intrathecal or intraplantar injections were performed 24 h after operation.The rats in DMSO1 and H1 groups were respectively intrathecally injected with 10％ DMSO (20 μl) and HC-030031 (50 μg).DMSO2 and H2 groups were respectively intraplantarlly injected with 10％ DMSO (40 μ l) and HC-030031 (100 μg).The paw withdrawal mechanical threshold (PWMT) was measured at 1 h before injection (T0),and 0.5 h (T1),1.0 h (T2),2.0 h (T3),4.0 h (T4) and 6.0 h (T5) after intrathecal or intraplantar injections.Four SD rats in each group were sacrificed at T4 and the segments of the spinal cord were obtained for determination of TRPA1 expression in the spinal cord by using Western blotting.Results As compared with C group [(34.4 ± 4.7) g] and Ⅰ group [(23.8 ±4.3) g],PWMT was significantly decreased and the expression of TRPA1 was up-regulated in DMSO1 and DMSO2 groups at T4 in spinal dorsal horn.The PWMT in H1 group [(28.3 ± 2.4) g] and H2 group [(29.1 ±4.2) g] was increased and the expression of TRPA1 was down-regulated at T4 as compared with DMSO1 group [(24.6 ±3.5) g] and DMSO2 group [(22.1 ±4.7) g].Conclusion Intrathecal or intraplantar administration with TRPA1 antagonists could attenuate incisional pain in rats. Key words: Incisional pain; Spinal cord; Transient receptor potential A1

Milk volatile organic compounds and fatty acid profile in cows fed timothy as hay, pasture, or silage

Nutrient composition and organoleptic properties of milk can be influenced by cow diets. The objective of this study was to evaluate the forage type effects on volatile organic compounds, fatty acid (FA) profile, and organoleptic properties of milk. Timothy grass was fed as hay, pasture, or silage during a period of 27 d to a group of 21 cows in a complete block design based on days in milk. Each cow also received 7.2kg/d of a concentrate mix to meet their nutrient requirements. Forage dry matter intake averaged 13.9kg/d and was not different among treatments. Milk yield was higher for cows fed pasture, intermediate for cows fed silage, and lowest for cows fed hay. However, milk fat content was higher for cows fed hay and silage, compared with cows fed pasture. As a result, fat-corrected milk and fat yield were not different among treatments. Increasing the supply of dietary cis-9,cis-12 18:2 (linoleic acid) and cis-9,cis-12,cis-15 18:3 (α-linolenic acid) when feeding pasture enhanced the concentration of these 2 essential FA in milk fat compared with feeding hay or silage. Moreover, the ratio of 16:0 (palmitic acid) to cis-9 18:1 (oleic acid), which is closely related to the melting properties of milk fat, was lower in milk from cows on pasture than in milk from cows fed hay or silage. Cows fed hay produced milk with higher levels of several free FA and γ-lactones, but less pentanal and 1-pentanol. More dimethyl sulfone and toluene were found in milk of cows on pasture. Cows fed silage produced milk with higher levels of acetone, 2-butanone, and α-pinene. Results from a sensory evaluation showed that panelists could not detect a difference in flavor between milk from cows fed hay compared with silage. However, a significant number of assessors perceived a difference between milk from cows fed hay compared with milk from cows fed pasture. In a sensory ranking test, the percentage of assessors ranking for the intensity of total (raw milk, fresh milk, and farm milk), sweet (empyreumatic, vanilla, caramel, and sugar), and grassy (grass, leafy vegetable, and plant) flavors was higher for milk from cows fed pasture compared with hay and silage. Using timothy hay, pasture, or silage harvested at a similar stage of development, the current study shows that the taste of milk is affected by the forage type fed to cows. More research is, however, needed to establish a link between the sensory attributes of milk and the observed changes in volatile organic compounds and FA profile.

Oxidation of Dimethyl Sulfoxide Solutions by Electrochemical Reduction of Oxygen

Oxygen reduction in nonaqueous electrolyte solutions containing Li salts is a complex field of research involving solution reactions with oxygen radicals and lithium oxides. The aprotic polar solvent dimethyl sulfoxide presents itself as a most promising candidate for a durable electrolyte for use in lithium–oxygen batteries. In the present study, we detail our in-depth study on dimethyl sulfoxide (DMSO) stability in the presence of electroactive lithium oxygen species on carbon electrodes. The question of the stability of DMSO is magnified by our use of carbon-fiber electrodes, which have relatively high specific surface-area and utilize low volumes of electrolyte solutions. This configuration has enabled us to identify even minor side-products such as LiOH, dimethyl sulfone, Li2SO3 and Li2SO4. The proposed mechanism of DMSO decomposition is supported by analytical measurements. These analyses confirm that during the reduction of oxygen on carbon electrodes, the solvent undergoes oxidation by reactive oxygen species and lithium oxides.

Infrared Spectroscopy Studies on Stability of Dimethyl Sulfoxide for Application in a Li–Air Battery

In situ infrared subtractive normalized Fourier transform infrared spectroscopy (SNIFTIRS) experiments performed simultaneously with the electroreduction of oxygen on gold and platinum cathodes in LiPF6 dimethyl sulfoxide (DMSO) electrolyte have shown that the solvent is stable with respect to nucleophilic attack by the electrogenerated superoxide radical anion. However, long-term experiments with KO2 solutions in DMSO have shown a slow formation of dimethyl sulfone. Evidence of dimethyl sulfone formation by anodic oxidation of DMSO above 4.2 V (Li/Li+) in the presence of trace water has been obtained on gold. On platinum, this unwanted reaction in the charging cycle of a lithium–air battery takes place at lower potentials, i.e., 3.5 V.

Optimized Metabolomic Approach to Identify Uremic Solutes in Plasma of Stage 3–4 Chronic Kidney Disease Patients

BackgroundChronic kidney disease (CKD) is characterized by the progressive accumulation of various potential toxic solutes. Furthermore, uremic plasma is a complex mixture hampering accurate determination of uremic toxin levels and the identification of novel uremic solutes.MethodsIn this study, we applied 1H-nuclear magnetic resonance (NMR) spectroscopy, following three distinct deproteinization strategies, to determine differences in the plasma metabolic status of stage 3–4 CKD patients and healthy controls. Moreover, the human renal proximal tubule cell line (ciPTEC) was used to study the influence of newly indentified uremic solutes on renal phenotype and functionality.ResultsProtein removal via ultrafiltration and acetonitrile precipitation are complementary techniques and both are required to obtain a clear metabolome profile. This new approach, revealed that a total of 14 metabolites were elevated in uremic plasma. In addition to confirming the retention of several previously identified uremic toxins, including p-cresyl sulphate, two novel uremic retentions solutes were detected, namely dimethyl sulphone (DMSO2) and 2-hydroxyisobutyric acid (2-HIBA). Our results show that these metabolites accumulate in non-dialysis CKD patients from 9±7 µM (control) to 51±29 µM and from 7 (0–9) µM (control) to 32±15 µM, respectively. Furthermore, exposure of ciPTEC to clinically relevant concentrations of both solutes resulted in an increased protein expression of the mesenchymal marker vimentin with more than 10% (p<0.05). Moreover, the loss of epithelial characteristics significantly correlated with a loss of glucuronidation activity (Pearson r = −0.63; p<0.05). In addition, both solutes did not affect cell viability nor mitochondrial activity.ConclusionsThis study demonstrates the importance of sample preparation techniques in the identification of uremic retention solutes using 1H-NMR spectroscopy, and provide insight into the negative impact of DMSO2 and 2-HIBA on ciPTEC, which could aid in understanding the progressive nature of renal disease.

Polar polymer membranes via thermally induced phase separation using a universal crystallizable diluent

Dimethyl sulfone (DMSO2) was used as a universal crystallizable diluent to prepare polar polymer membranes via thermally induced phase separation (TIPS). The polar polymers adopted herein include poly(vinylidene fluoride) (PVDF), polyacrylonitrile (PAN) and cellulose acetate (CA). Intensive investigation was carried out to study the phase separation behaviors and the membrane performances. Equilibrium phase diagrams and polarized optical microscope results indicate a solid−solid phase separation mechanism for all the three polar polymer/diluent systems. Scanning electron microscopy observations show that tubular-like pores are irregularly distributed in the PVDF and PAN membranes, whereas a compacted structure can be found in the CA membranes. The pore size, surface porosity, water flux and overall porosity become large when the membranes are prepared with low polymer concentration or at small cooling rate. Results of tensile tests confirm that the mechanical strength of the membranes can be enhanced by increasing the polymer concentration or cooling rate. Moreover, DMSO2 has been efficiently recovered by recrystallization and sublimation. In conclusion, this work may provide a green preparation method to produce polar polymeric membranes via TIPS.