Search

NaMMT clay incorporated and maleic acid (MA) crosslinked polyvinyl alcohol (PVA)-chitisan (CS) interpenetrating network (IPN) type nanocomposite membranes were prepared for dehydration of acetone by pervaporation (PV). FTIR, XRD, SEM, UV spectroscopy, mechanical properties, contact angle measurement, and DTA-TGA were used to characterize these membranes. The effect of clay, CS, and MA on the flux and separation factor for water were statistically optimized by Box-Behnken design (BBD). Accordingly, the membrane prepared with 39.3 wt.% CS, 3 wt.% each of MA and NaMMT nanoclay showed a flux/separation factor of 0.176-0.733 kg/[m.sup.2]h/ 277-168 for the pervaporative dehydration of 99 wt.% acetone. Highlights * IPN nanocomposite membranes were prepared from PVA, CS, and nano clay. * Structure and properties of the IPNs were characterized. * Synthesis parameters were optimized by BBD. * Membranes showed high flux and water selectivity for acetone dehydration by PV. KEYWORDS acetone dehydration, box-Behnken design, chitosan, pervaporation, polyvinyl alcohol, sodium montmorillonite, 1 | INTRODUCTION Acetone is a volatile organic solvent extensively used in various chemical process industries such as paints, plastics, leather, explosive, and pharmaceuticals. A trace amount of water present [...]

Metastable monotectic Cu-50 at. % Co alloy produced by arc melting has been processed under micro gravity condition using a drop tube and subjected to differential thermal analysis (DTA). Microstructural evidence from the as solidified sample revealed that rapid cooling of the arc melt process was enough to incite liquid phase separation in the alloy. In the drop tube samples, the melting temperature of the [beta]-phase (Cu-rich) was determined to be 1294.8 K, whereas that of the [alpha]-phase (Co-rich) was found to vary with cobalt content. Key words: liquid phase separation, monotectic solidification, differential thermal analysis (DTA), drop tube, metastable alloys. Nous avons traite en conditions de microgravite un alliage metastable monotectique de Cu-50 % at. Co produit par fusion a l'arc au moyen d'un tube a compte-gouttes et nous l'avons soumis a une analyse thermique differentielle (ATD). Des donnees microstructurales issues de l'echantillon solidifie ont revele que le refroidissement rapide associe au processus de fusion a l'arc etait suffisant pour induire la separation de phases liquides dans l'alliage. Dans les echantillons des tubes a compte-gouttes, nous avons determine que la temperature de fusion de la phase [beta] (riche en Cu) etait de 1294,8 K, tandis que celle de la phase [alpha] (riche en Co) variait selon la teneur en cobalt. Mots-cles : separation de phase liquide, solidification monotectique, analyse thermique differentielle (ATD), tube a compte-gouttes, alliages metastables., Introduction There has been significant research on the equiatomic Cu-Co alloy ([Cu.sub.50][Co.sub.50]) due to the symmetrical metastable miscibility gap (MG) said to exist in the alloy system. (1-3) Nakagawa, (1) [...]

Incorporation of inorganic fillers into Polysulfone (PSF) to constitute mixed matrix membranes (MMMs) has become a viable solution to prevail over limitations of the pristine materials in natural gas sweetening process. Nevertheless, preparation of MMMs without defects and empirical investigation of membrane that exhibits characteristic of improved C[O.sub.2]/C[H.sub.4] separation performance at experimental scale are difficult that require prior knowledge on compatibility between the filler and polymer. A computational framework has been conducted to construct validated PSF based MMMs using silica (Si[O.sub.2]) as inorganic fillers. It is known that nanosized Si[O.sub.2] can coexist in varying polymorph configurations (ie, [alpha]-Quartz, [alpha]-Cristobalite, [alpha]-Tridymite) but molecular simulation study of Si[O.sub.2] polymorphs to form MMMs is limited. Therefore, this work is a pioneering study to elucidate feasibility in facile utilization of polymorphs to improve gas separation performance of MMMs. Physical properties and gas transport behavior of the simulated PSF based MMMs with different Si[O.sub.2] polymorphs and loadings have been elucidated. The optimal MMM has been found to be PSF/25 wt% [alpha]-Cristobalite at 55[degrees]C. The success in molecular simulation has shed light on how computational tools can provide understandings at molecular level to elucidate compatibility between varying pristine materials to MMMs for natural gas processing. KEYWORDS C[O.sub.2]/C[H.sub.4] separation, membrane, molecular simulation, polysulfone, [alpha]-Cristobalite, [alpha]-Quartz, [alpha]-Tridymite, 1 | INTRODUCTION Carbon dioxide (C[O.sub.2]) capture from natural gas is essential to comply with methane (C[H.sub.4]) product specification while simultaneously mitigating greenhouse gas environmental effect. [1] Glassy polymeric membrane [...]

The proteasome is a major proteolytic machine that regulates cellular proteostasis through selective degradation of ubiquitylated proteins.sup.1,2. A number of ubiquitin-related molecules have recently been found to be involved in the regulation of biomolecular condensates or membraneless organelles, which arise by liquid-liquid phase separation of specific biomolecules, including stress granules, nuclear speckles and autophagosomes.sup.3-8, but it remains unclear whether the proteasome also participates in such regulation. Here we reveal that proteasome-containing nuclear foci form under acute hyperosmotic stress. These foci are transient structures that contain ubiquitylated proteins, p97 (also known as valosin-containing protein (VCP)) and multiple proteasome-interacting proteins, which collectively constitute a proteolytic centre. The major substrates for degradation by these foci were ribosomal proteins that failed to properly assemble. Notably, the proteasome foci exhibited properties of liquid droplets. RAD23B, a substrate-shuttling factor for the proteasome, and ubiquitylated proteins were necessary for formation of proteasome foci. In mechanistic terms, a liquid-liquid phase separation was triggered by multivalent interactions of two ubiquitin-associated domains of RAD23B and ubiquitin chains consisting of four or more ubiquitin molecules. Collectively, our results suggest that ubiquitin-chain-dependent phase separation induces the formation of a nuclear proteolytic compartment that promotes proteasomal degradation. Hyperosmotic stress leads to a phase separation of the proteasome, triggered by interactions between RAD23B and ubiquitylated proteins, which bring together p97 and proteasome-associated proteins into nuclear proteolytic foci., Author(s): Sayaka Yasuda [sup.1] , Hikaru Tsuchiya [sup.1] , Ai Kaiho [sup.1] , Qiang Guo [sup.2] , Ken Ikeuchi [sup.3] [sup.4] , Akinori Endo [sup.1] , Naoko Arai [sup.1] , [...]

Microfluidic systems can deliver portable point-of-care diagnostics without the need for external equipment or specialist operators, by integrating all reagents and manipulations required for a particular assay in one device.sup.1. A key approach is to deposit picogram quantities of dried reagents in microchannels with micrometre precision using specialized inkjet plotters.sup.2-5. This means that reagents can be stored for long periods of time and reconstituted spontaneously when adding a liquid sample. But it is challenging to carry out complex operations using multiple reagents, because shear flow enhances their dispersion and they tend to accumulate at moving liquid fronts, resulting in poor spatiotemporal control over the concentration profile of the reconstituted reagents.sup.6. One solution is to limit the rate of release of reagents into the liquid.sup.7-10. However, this requires the fine-tuning of different reagents, conditions and targeted operations, and cannot readily produce the complex, time-dependent multireagent concentration pulses required for sophisticated on-chip assays. Here we report and characterize a capillary flow phenomenon that we term self-coalescence, which is seen when a confined liquid with a stretched air-liquid interface is forced to 'zip' back onto itself in a microfluidic channel, thereby allowing reagent reconstitution with minimal dispersion. We provide a comprehensive framework that captures the physical underpinning of this effect. We also fabricate scalable, compact and passive microfluidic structures--'self-coalescence modules', or SCMs--that exploit and control this phenomenon in order to dissolve dried reagent deposits in aqueous solutions with precise spatiotemporal control. We show that SCMs can reconstitute multiple reagents so that they either undergo local reactions or are sequentially delivered in a flow of liquid. SCMs are easily fabricated in different materials, readily configured to enable different reagent manipulations, and readily combined with other microfluidic technologies, so should prove useful for assays, diagnostics, high-throughput screening and other technologies requiring efficient preparation and manipulation of small volumes of complex solutions. Characterization of a capillary flow phenomenon termed self-coalescence leads to the development of scalable, compact microfluidic devices that could see application in diagnostics, high-throughput screening and biological assays., Author(s): Onur Gökçe [sup.1] [sup.5] , Samuel Castonguay [sup.2] , Yuksel Temiz [sup.1] , Thomas Gervais [sup.2] [sup.3] [sup.4] , Emmanuel Delamarche [sup.1] Author Affiliations: (1) IBM Research-Zurich, Rüschlikon, Switzerland [...]

Viscoelastic phase separation (VPS) is a fundamental physical phenomenon that creates percolated network structure in dynamically asymmetric mixtures. The object of this study was to investigate the effect of rod shape nanoparticies with different surface chemistries on VPS in the polystyrene/poly(vinyl methyl ether), PS/PVME, blend. For this purpose, hydrophilic (CNWs) and hydrophobic (M-CNWs) cellulose nanowhiskers (CNWs) were prepared to be used as nanorods. Rheological measurments were employed to investigate the effect of nanowhiskers on phase separation temperature, kinetics of phase separation, and dynamic asymmetry. The evolution of morphology during the phase separation at a fixed quench depth was assessed using polarized optical microscopy. The nanowhiskers were effective in decreasing the correlation length, which slowed down the phase separation. CNWs self-assembled into the PVME-rich phase during the phase separation, which led to a decrease in the dynamic asymmetry and beyond a critical volume fraction of CNWs, the VPS mechanism changed to spinodal decomposition (SD). However, in the presence of M-CNW, the localization of M-CNWs into the PS-rich phase enhanced the dynamic asymmetry and at 2 vol% M-CNWs, the induced PS-rich network by VPS was arrested. The linear and non-linear viscoelastic behavior of the samples were Studied as well. POLYM. ENG. SCI., 58:920-942, 2018. [C] 2017 Society of Plastics Engineers, INTRODUCTION Phase separation in polymer blends is of scientific and practical interest as different mechanisms of phase separation yield different morphologies which are related to various functions associated with electrical, [...]

The capacity to isolate and study single cardiomyocytes has dramatically enhanced our understanding of the fundamental mechanisms of the heart. Currently, 2 primary methods for the isolation of cardiomyocytes are employed: (i) the neonatal isolation protocol and (ii) the Langendorff isolation method. A major limiting feature of both procedures is the inability to isolate cardiomyocytes between 3 days and 3 weeks after birth. Herein, we report the establishment and validation of a new method for the rapid and efficient isolation of mouse cardiomyocytes, regardless of age. This novel procedure utilizes whole heart perfusion of a trypsin-collagenase Krebs-based buffer through the left ventricle at a high flow rate. Cardiomyocytes can be isolated in significantly less time with a simple, syringe-pump-based apparatus. Typically, we can digest 10-15 hearts per hour. Altogether, we have established an efficient and reproducible method for the rapid isolation of fresh cardiomyocytes from postnatal mouse hearts of any age. Key words: cardiomyocyte, isolation, cardiac, perfusion, neonatal, fibroblast. La possibilite d'isoler et d'etudier des cardiomyocytes uniques a permis d'ameliorer considerablement notre comprehension des modes d'action fondamentaux du coeur. Actuellement, nous employons principalement 2 methodes pour isoler les cardiomyocytes : (i) le protocole d'isolation neonatale et (ii) la methode d'isolation en Langendorff. Un element limitatif majeur de ces deux procedures correspond a l'impossibilite d'isoler des cardiomyocytes de 3 jours a 3 semaines apres la naissance. Ici, nous rapportons la mise au point et la validation d'une nouvelle methode permettant d'isoler rapidement et de maniere efficace des cardiomyocytes de souris, sans egard a l'age. Cette nouvelle procedure met a profit la perfusion de coeurs entiers de trypsine et de collagenase en tampon de Krebs a haut debit a travers le ventricule gauche. Les cardiomyocytes peuvent etre isoles en nettement moins de temps a l'aide d'un appareil constitue d'une pompe seringue. Ordinairement, nous sommes en mesure de digerer de 10 a 15 coeurs a l'heure. Somme toute, nous avons mis au point une methode efficace et reproductible pour l'isolation rapide de cardiomyocytes frais provenant de coeurs de souris postnatales de tous ages. [Traduit par la Redaction] Mots-cles : cardiomyocyte, isolation, cardiaque, perfusion, neonatal, fibroblaste., Introduction Although the medical community has made great strides in reducing the morbidity and mortality from heart disease, it remains one of the leading causes of death worldwide (Benjamin et [...]

Using a solution technique, tetraethylorthosilicate cross-linked hybrid polyvinyl alcohol) membrane was prepared. The membrane was further incorporated with 0, 10, 20, and 30 mass% of mesoporous carbon and the membranes thus obtained were designated as M-1, M-2, M-3, and M-4, respectively. The physico-chemical properties of these membranes were investigated using Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, differential scanning calorimetry, thermogravimetry analysis, and scanning electron microscopy. The effects of mesoporous carbon and feed composition on pervaporation performance of the membranes were systematically investigated. The membrane M-4 exhibited the highest separation factor of 4,082 with a flux of 1.93 x [10.sup.-2] kg/ m h at 30[degrees]C for 10 mass% of water in the feed. Total flux and flux of water are overlapping each other, manifesting that these membranes could be used to break the azeotropic point of water-isopropanol mixtures effectively. From the temperature dependent diffusion and permeation values, the Arrhenius activation parameters were estimated. The positive heat of sorption values was obtained for M-1, M-2, and M-3, suggesting that Henry's mode of sorption is predominant, giving an endothermic contribution. On the contrary, membrane M-4 exhibited negative [DELTA][H.sub.S] value suggesting that the sorption process was dominated by exothermic contribution., INTRODUCTION Pervaporation (PV) is a promising technique, which involves the phenomenon of both permeation and evaporation [1, 2], The technical feasibility of PV for mass transport mainly depends on membrane [...]

Swelling and adsorption properties of poly(hydroxamic acid), (PHA) hydrogels in aqueous solutions of some phenazine dyes such as Neutral Red, Safranin T, and Janus Green have been investigated. PHA hydrogels containing N,N' methylenebisacrylamide or ethyleneglycoldimethacrylate were used in experiments on swelling, diffusion and adsorption of the dyes. The equilibrium swelling ([S.sub.eq]) values of PHA hydrogels in aqueous solutions of the phenazine dyes were calculated as 2.16-33.25 g [g.sup.-1]. Swelling kinetic parameters such as initial swelling rate, swelling rate constant, and maximum swelling were found. Dye diffusion into hydrogels was found to be non-Fickian in character. Diffusion coefficients are ranged 1.32 x [10.sup.-6] [cm.sup.2] [s.sup.-1] - 44.70 x [10.sup.-6] [cm.sup.2] [s.sup.-1]. Adsorption of the phenazine dyes onto PHA hydrogels was studied by batch technique. PHA hydrogels in the phenazine dye solutions showed the dark coloration. The data was found that Freundlich isotherm model fits. According the Freundlich constants, the adsorption isotherms are of S-type in Giles classification. All swelling and binding parameters for PHA-EGDMA were found to be higher than those for PHA-NNMBA. The type of crosslinker influenced the swelling, binding, and sorption more than the type of dye. Finally, it can be said that PHA hydrogels may be used a sorbent for removal of dyes., INTRODUCTION Hydrogels are a unique class of macromolecular networks that may contain a large fraction of aqueous solvent within their structure. The hydrophilicity of the network is due to the [...]

The blend polyethersulfone (PES)/cellulose acetate (CA) flat-sheet microporous membranes were prepared by reverse thermally induced phase separation (RTIPS) process. The effects of CA content and coagulation bath temperature on membrane structures and properties were investigated in terms of membrane morphology, water contact angle, permeation performance, and mechanical properties. The cloud point results indicated that the cloud point decreased with the increasing content of CA. When the coagulation bath temperature was lower than the cloud point, the membrane formation process underwent nonsolvent induced phase separation (NIPS) process and dense skin layer and finger-like structure were formed in membranes. These membranes had lower pure water flux and poor mechanical properties. But when the coagulation bath temperature was higher than the cloud point, the membrane formation process underwent RTIPS process. The porous top surface as well as porous cross-section of the membranes were formed. Therefore, high pure water flux and good mechanical properties were obtained. The contact angles results indicated that the hydrophilicity of the prepared membranes improved obviously with the addition of CA. When the content of CA was 0.5 wt% and the membrane formation temperature was 323K, the PES/CA microporous membrane which was prepared via the RTIPS process displayed a optimal permeability of the pure water flux of 816 L [m.sup.-2] [h.sup.-1] and the BSA rejection rate of 49.5%, which showed an increase of 48.9% and 23.6% than that of pure PES membrane, respectively. Moreover, the mechanical strengths of the membranes obtained by RTIPS process were better than those membranes prepared by NIPS process., INTRODUCTION Over the past decades, a variety of membrane formation methods have been developed, such as stretching, track etching, sintering, and phase separation process [1-3]. Among these techniques, phase separation [...]

A new chiral sorbent based on mercaptosilica modified by gold nanoparticles, then treated by [beta]-mercaptopropionic acid and macrocyclic antibiotic vancomycin, was obtained. The enantioseparation of isomeric [beta]-blockers (nadolol, atenolol, metoprolol, alprenolol, oxprenolol, and pindolol) by HPLC was studied on the synthesized sorbent. The effect of the composition of the mobile phase (nature and concentration of the organic solvent, concentration and pH of the buffer solution) on retention times of [beta]-blocker enantiomers, selectivity of separation, and resolution of chromatographic peaks were studied. The best separation was achieved for pindolol and metoprolol. The procedure was used to determine the pindolol enantiomers in the preparation 'Visken,' and metoprolol in the 'Vazocardin' preparation. Keywords: [beta]-blockers, enantiomers, high-performance liquid chromatography, macrocyclic antibiotic, vancomycin, gold nanoparticles DOI: 10.1134/S1061934818020028, Current trends in the development of the pharmaceutical industry indicate a growing need in obtaining optically pure dosage forms. Many synthetic drugs occur as of two or more spatial isomers. [...]

Chromatographic behavior of some amino acids in aqueous-organic and aqueous modified micellar mobile phases is studied by thin-layer liquid chromatography. Intrinsic basic laws, features, possibilities, and limitations are revealed. It is shown that the efficiency of the chromatographic separation of amino acids in the presence of electrolytes is significantly improved in micellar mobile phases. Keywords: amino acids, separation, thin-layer chromatography, modified micellar mobile phases, electrolytes DOI: 10.1134/S1061934817080111, [alpha]-Amino acids (AA) possess high biological activity and are widely used in medicine, pharmaceutics, sports, food industry, animal industry, and other areas of human activity [1-4]. The properties of all [...]

A methodology for separation, characterization, and quantitative elemental analysis of volcanic ash nanoparticles is proposed. A combination of field-flow fractionation in a rotating coiled column and membrane filtration is used in the isolation and separation of nanoparticles. The size and morphology of nanoparticles were studied by static light scattering and scanning electron microscopy. The concentration of major- and trace elements in the bulk sample and the separated fractions was determined by inductively coupled plasma atomic emission spectrometry and mass spectrometry. It is shown that the total concentrations of most elements in the ash sample are comparable to their average concentrations in the Earth's crust. On the other side, in the fraction 50-100 nm, the concentrations of Ni, Zn, Ag, Sn, Sb, Pt, Tl, Pb, and Bi are one or two orders of magnitude higher than their total concentrations, which probably indicates the preconcentration of corresponding elements from volcanic gases by nanoparticles. In the fraction represented by water-soluble forms of elements and nanoparticles smaller than 50 nm, Cu, Zn, Pb, and several other elements are found; the partition of elements between the solution and solid phase (nanoparticles) is assessed. The proposed methodology requires further development and application to the analysis of volcanic ash from various regions of the Globe. Keywords: volcanic ash, nanoparticles, elemental composition, toxic elements, rotating coiled columns, fieldflow fractionation, membrane filtration, inductively coupled plasma atomic emission spectrometry, inductively coupled plasma mass spectrometry, Volcanoes are one of the main sources of natural nanoparticles [1]. During eruption, a column of ash is emitted in the atmosphere, the height of which in some cases exceeds [...]

TS-1 molecular sieves were synthesized and characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and UV-Vis spectroscopy. Results showed that the morphology, crystallinity, and purity of TS-1 were closely related to the Ti/Si ratio, crystallization time, crystallization temperature, and calcination time. The TS-1 particles were incorporated into polydimethylsiloxane to form mixed matrix membranes (MMMs), and these MMMs were first used to separate ethanol/water mixtures via pervaporation. The MMMs with 50 wt% TS-1 (Ti/Si ratio of 0.02) loading showed the highest separation factor of 14.1 for 5 wt% ethanol feed concentration at 50°C. POLYM. ENG. SCI., 56:583-589, 2016. [C] 2016 Society of Plastics Engineers, INTRODUCTION Pervaporation is a clean, environmentally friendly, and energy-efficient separation technology. It has been used to separate close boiling liquids and azeotropic mixtures, which are difficult to separate using conventional [...]

The properties of a Diasorb-130-IDK sorbent based on silica gel with a grain size of about 6 pm were studied in order to choose conditions for the separation of the rare-earth elements from the samples of natural wine and their subsequent determination by inductively coupled plasma mass spectrometry. The possibility of the quantitative separation of the elements with the use of an ultrasonic flow suspension column was demonstrated. The results were compared with data obtained with the use of other sample preparation methods. A procedure was proposed for the determination of the rare-earth elements and yttrium in the samples of wines. Keywords: suspension columns, ultrasound, rare-earth metals, wine DOI: 10.1134/S1061934815120059, Sorption methods for the preconcentration of analytes are widely used in analytical chemistry. Various grainy sorbents are commonly used in the form of packed beds retained in a column or [...]

A two-phase system of polyethylene glycol PEG-1500 ([C.sub.2][H.sub.5]OH, [C.sub.3][H.sub.7]OH)-ammonium sulfate-water is proposed for the selective extraction and spectrometric determination of vanadium(IV) as its thiocyanate complex. The conditions of the separation of vanadium(IV) from vanadium(V) are optimized using polyethylene glycol or water soluble alcohols. The detection limit for vanadium(IV) in extraction-atomic absorption determination is 2.8 µg/L and in combined photometric determination with chromazurol S, 10 µg/L. The methods are tested on mine, waste, and river waters. The relative standard deviation does not exceed 7%. The duration of analysis is 20 min. Keywords: vanadium(IV), vanadium(V), thiocyanate complex, chromazurol S, two-phase aqueous systems, spectrophotometry, atomic absorption spectrometry DOI: 10.1134/S1061934814070132, The determination of vanadium in different valence states is of great value in water analysis because of their difference in toxicity, biological availability, and wide abundance. Natural waters contain V(V) [...]

The separation of hydrocarbons (methane, ethane, propane, n-butane, ethylene, and propylene) and sulfur-containing gases (hydrogen disulfide, sulfur dioxide, carbonyl sulfide) on a new mixed stationary phase poly-(1-trimethylsilyl-1-propyne)/poly-(1-phenyl-1 -propyne) in the presence of water has been studied by gas chromatography. It has been demonstrated that the new mixed stationary phase outperforms the known polymeric adsorbents and stationary phases by resolution, asymmetry factor, and column efficiency. Keywords: gas chromatography, mixed stationary phase, poly-(1-trimethylsilyl-1-propyne), poly-(1-phenyl-1-propyne), hydrocarbon gases, sulfur-containing gases, water DOI: 10.1134/S1061934813070125, INTRODUCTION Gas chromatography (GC) both in gas--liquid and gas--adsorption versions is widely used for the technological control of industrial processes; control of finished goods in various branches of industry (gas- [...]

We have demonstrated the advantages of the dynamic preconcentration and separation of Pd(II) and Pt(IV) on paper carriers modified with 3-methyl-2,6-dimercapto-1,4-thiopyrone. The optimal conditions of the solid-phase reaction have been determined in Pd(II) sorption; after its separation Pt(IV), has been preconcentrated by sorption as its dimercaptides. Test scales have been produced for the visual determination of 0.5-40 µg Pd(II) and 1-195 µg Pt(IV) in 10- and 100 mL-samples, respectively. In addition, a procedure of their sorption--chromaticity densitometry determination from a single aliquot portion has been developed with detection limits of 5 and 1 ng/mL, respectively, and a procedure of Pd(II) determination using a test strip ([c.sub.min] = 0.40 mg/L) has been proposed. The procedures have been applied to the determination of palladium and platinum in electrolytes, sludges, and alloys. Keywords: palladium(II), platinum(IV), sorption, preconcentration, separation, 3-methyl-2,6-dimercapto-1,4-thiopyrone, densitometric determination DOI: 10.1134/S1061934813050055, Because of their unique properties, platinum metals (PM) are indispensable materials in chemical, electrical, and oil processing industries; medicine; and other areas. The application of nanomaterials in modern chemical technologies, [...]

A method is proposed for the luminescence determination of neptunium in natural waters with the removal of interfering iron. For the separation of iron ionic and colloidal species, solid-phase extraction with N-benzoyl-phenylhydroxylamine as a complexing reagent is used. The method makes possible the reduction of iron concentration in samples by more than two orders of magnitude without noticeable losses of neptunium and, therefore, the attainment of a detection limit for neptunium equal to its value in samples containing no iron. Keywords: luminescence, crystal phosphor, neptunium, iron DOI: 10.1134/S1061934813030076, Long-living isotopes of actinide elements are dangerous environmental pollutants. The known techniques of their analysis, i.e., α-spectrometry, neutron activation analysis, and mass spectrometry, necessitate complex sample pretreatment to remove interfering [...]

In this work, tubular poly-left-lactic acid scaffolds for vascular tissue engineering applications were produced by an innovative two-step method. The scaffolds were obtained by performing a dip-coating around a nylon fiber, followed by a diffusion induced phase separation process. Morphological analysis revealed that the internal lumen of the as-obtained scaffold is equal to the diameter of the fiber utilized; the internal surface is homogeneous with micropores 1-2 pm large. Moreover, a porous open structure was detected across the thickness of the wails of the scaffold. An accurate analysis of the preparation process revealed that it is possible to tune up the morphology of the scaffold (wall thickness, porosity, and average pore dimension), simply by varying some experimental parameters. Preliminary in vitro cell culture tests were carried out inside the scaffold. The results showed that cells are able to grow within the internal surface of the scaffolds and after 3 weeks they begin to form a 'primordial' vessel-like structure. Modeling predictions of the dip-coating process display always an underestimate of experimental data (dependence of wall thickness upon extraction rate). POLYM. ENG. SCI., 53:431-442, 2013. [C] 2012 Society of Plastics Engineers, INTRODUCTION A great deal of research has been pursued in the last decade with the goal of developing blood vessel substitutes, owing to the large impact this advance would have [...]

Silica-filled polydimethylsiloxane (PDMS) composite membranes are prepared on a polytetrafluoroethylene support structure. The structure and the performance of the membranes are characterized by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetry. The pervaporation process for acetic/water separation is performed within the PDMS membranes. The vulcanization temperature was found to have a great influence on the separation performance of the membrane. The addition of silica can significantly improve the pervaporation flux and enhance the thermal stability of the membrane. With an increase in the feed temperature, selectivity decreases and permeation flux increases. Performed with a pure PDMS membrane vulcanized at 30°C, the separation factor at first will increase, then decrease when the feed flow rate was increased from 14 to 38 L * [h.sup.-1]. The maximum separation factor is achieved when the feed flow rate is 26 L * [h.sup.-1]. POLYM. ENG. SCI., 51:819-825, 2011. [C]2011 Society of Plastics Engineers, INTRODUCTION Membrane pervaporation is one of the more promising candidates for low-cost separation processes, especially for mixtures of close volatility or for mixtures with thermal or chemical sensitivity (1). Membrane [...]

A review of photoinduced charge separation of organic molecules in microporous and mesoporous materials is presented. In particular, the photoionization of A-alkylphenothiazine ([PC.sub.n]), A,A,A,A'-tetramethylbenzidine (TMB), and porphyrin in microporous materials, such as zeolites, aluminophosphates (AlPOs), silicoaluminophosphates (SAPOs), and mesoporous materials, such as MCM-41, MCM-48, and SBA-15, is discussed. Key words: photoinduced charge separation, photoionization, microporous, mesoporous materials. On presente une revue de la separation de charge photoinduite des molecules organiques dans des mateeriaux microporeux et mesoporeux. On discute particulierement des cas des A-alkylphenothiazines ([PC.sub.n]), de la A,A,A',A'-tetramethylbenzidine (TMB) et de la porphyrine dans des mateeriaux microporeux tels les zeolites, les aluminophosphates (AlPO) et les silicoaluminophosphates (SAPO) ainsi que les mateeriaux mesoporeux tels le MCM-41, le MCM-48 et le SBA-15. Mots-cles: separation de charge photoinduite, photoionisation, materiaux microporeux et mesoporeux. [Traduit par la Redaction], Introduction Solar energy conversion and storage has gained renewed interest in the past few years. (1-11) The scientific community is engaged in the pursuit of exploring the possibility of using [...]

ABSTRACT One major challenge faced by Beijing is dealing with the enormous amount of municipal solid waste (MSW) generated, which contains a high percentage of food waste. Source separation is [...]

Tamoxifen (Tam), the antiestrogen used to treat estrogen receptor-positive breast cancer is a pro-drug that is converted to its major active metabolites, endoxifen and 4-hydroxy-tamoxifen (4-OH-Tam) by various biotransformarion enzymes of which cytochrome P450-2D6 (CYP2D6) is key. The usual Tam dose is 20 mg daily; however, the plasma active metabolite concentrations vary due to common generic variants encoding the biotransformation enzymes and environmental factors (e.g., concomitant drugs) that inhibit these enzymes. Effective treatment depends on adequate Tam conversion to its active isomers. To monitor metabolite plasma levels, a novel liquid chromatography-tandem mass spectrometry (LC-MS/ MS) method was developed to separate and quantitate Tam, N-desmethyl-tamoxifen (ND-Tam), and tamoxifen-N-oxide (Tam-N-oxide), and the E, Z, and Z isomers of endoxifen and 4-OH-Tam. Known standards were used to identify each metabolite/isomer. Quantitation of these metabolites in plasma was linear from 0.6 to 2000 nM. Intra- and inter-assay reproducibilities were 0.2-8.4% and 0.6-6.3%, respectively. Accuracy determined by spike experiments with known standards was 86-103%. Endoxifen, 4-OH-Tam, and their isomers were stable in fresh frozen plasma for [greater than or equal to]6 months. This method provides the first sensitive, specific, accurate, and reproducible quantitation of Tam and its metabolite isomers for monitoring Tam-treated breast cancer patients. 10.1021/ac102337d

The efficacy of a single dielectric barrier discharge plasma actuator for controlling turbulent boundary-layer separation from the deflected flap of a high-lift airfoil is investigated between Reynolds numbers of 240,000 (15 m/s) and 750,000 (45 m/s). Momentum coefficients for the dielectric barrier discharge plasma actuator are approximately an order of magnitude lower than those usually employed for such studies, yet control authority is still realized through amplification of natural vortex shedding from the flap shoulder, which promotes momentum transfer between the freestream and separated region. This increases dynamic loading on the flap and further organizes turbulent fluctuations in the wake. The measured lift enhancement is primarily due to upstream effects from increased circulation around the entire model, rather than full reattachment to the deflected flap surface. Lift enhancement via instability amplification is found to be relatively insensitive to changes in angle of attack, provided that the separation location and underlying dynamics do not change. The modulation waveform used to excite low- frequency perturbations with a high-frequency plasma-carrier signal has a considerable effect on the actuator performance. Control authority decreases with increasing Reynolds number and flap deflection, highlighting the necessity for further improvement of plasma actuators for use in realistic takeoff and landing transport aircraft applications. These findings are compared to studies on a similar high-lift platform using piezoelectric-driven zero- net-mass flux actuation. DOI: 10.2514/1.J050452