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Purification of valuable engineered proteins and enzymes can be laborious, costly, and generating large amount of chemical waste. Whilst enzyme immobilization can enhance recycling and reuse of enzymes, conventional methods for immobilizing engineered enzymes from purified samples are also inefficient with multiple-step protocols, regarding both the carrier preparation and enzyme binding. Nickel ferrite magnetic nanoparticles (NiFe2O4 MNPs) offer distinct advantages in both purification and immobilization of enzymes. In this work, we demonstrate the preparation of NiFe2O4 MNPs via a one-step solvothermal synthesis and their use in direct enzyme binding from cell lysates. These NiFe2O4 MNPs have showed an average diameter of 8.9 ± 1.7 nm from TEM analysis and a magnetization at saturation (Ms) value of 53.0 emu g–1 from SQUID measurement. The nickel binding sites of the MNP surface allow direct binding of three his-tagged enzymes, d-phenylglycine aminotransferase (d-PhgAT), Halomonas elongata ω-transaminase (HeωT), and glucose dehydrogenase from Bacillus subtilis (BsGDH). It was found that the enzymatic activities of all immobilized samples directly prepared from cell lysates were comparable to those prepared from the conventional immobilization method using purified enzymes. Remarkably, d-PhgAT supported on NiFe2O4 MNPs also showed similar activity to the purified free enzyme. By comparing on both carrier preparation and enzyme immobilization protocols, use of NiFe2O4 MNPs for direct enzyme immobilization from cell lysate can significantly reduce the number of steps, time, and use of chemicals. Therefore, NiFe2O4 MNPs can offer considerable advantages for use in both enzyme immobilization and protein purification in pharmaceutical and other chemical industries. [ABSTRACT FROM AUTHOR]

Nano-scale extracellular vesicles are lipid-bilayer delimited particles that are naturally secreted by all cells and have emerged as valuable biomarkers for a wide range of diseases. Efficient isolation of small extracellular vesicles while maintaining yield and purity is crucial to harvest their potential in diagnostic, prognostic, and therapeutic applications. Most conventional methods of isolation suffer from significant shortcomings, including low purity or yield, long duration, need for large sample volumes, specialized equipment, trained personnel, and high costs. To address some of these challenges, our group has reported a novel insulator-based dielectrophoretic device for rapid isolation of small extracellular vesicles from biofluids and cell culture media based on their size and dielectric properties. In this study, we report a comprehensive characterization of small extracellular vesicles isolated from cancer-patients' biofluids at a twofold enrichment using the device. The three-fold characterization that was performed using conventional flow cytometry, advanced imaging flow cytometry, and microRNA sequencing indicated high yield and purity of the isolated small extracellular vesicles. The device thus offers an efficient platform for rapid isolation while maintaining biomolecular integrity. [ABSTRACT FROM AUTHOR]

Nickel-zinc ferrites, which have pronounced ferrimagnetic and semiconductor properties, can be used as promising magnetically controlled photocatalysts for the purification of aqueous media from organic pollutants. The value of the specific surface area largely affects the photocatalytic properties of the material; therefore, the possibility of its control and variation at the stage of synthesis is of great scientific and technical interest. In this study, nanocrystalline ferrite of the Zn0.5Ni0.5Fe2O4 composition is obtained under conditions of solution combustion using various types of organic fuel as the main factor affecting the formation of the specific surface area, and subsequent heat treatment in air at a temperature of 500°C for 2 h. The crystal structure, chemical composition, and morphology of Zn0.5Ni0.5Fe2O4 are studied by methods of X‑ray phase analysis, X-ray spectral microanalysis, and scanning electron microscopy. The values of the specific surface area of the synthesized nanopowders are calculated based on the method of liquid-phase adsorption from a Methylene Blue solution and the low-temperature adsorption-desorption of nitrogen. The results of the X‑ray phase analysis show that a single-phase nanocrystalline product with a spinel structure is formed, where the average crystallite size varies within 11–23 nm and is inversely related to the value of the specific surface area, respectively, after the reaction with succinic acid (39.1 m2/g) and with glycine (20.2 m2/g). It is established that the choice of the fuel largely affects the formation of nanocrystals and the specific surface area of the samples, and the approach used makes it possible to control its values. [ABSTRACT FROM AUTHOR]

GaSb-based thin films are expected to be applicable to biomedical and environmental devices requiring efficient operation in the near-infrared region. In this study, the effects of dilute Bi doping on the structural properties and chemical stability of GaSb thin films were examined. GaSb and GaSb1−xBix (x = 0.011, 0.013, or 0.032) thin films were grown at 320 °C on quartz substrates and PI films by multi-cathode RF magnetron sputtering. The crystallinity of the GaSb/quartz was superior to that of the GaSb/PI. Bi doping improved the crystallinity of the GaSb thin films with the exception of GaSb0.968Bi0.032/quartz, for which the crystallinity deteriorated owing to abnormal growth due to Bi cluster formation. In addition, the crystallinity of GaSb1−xBix/PI was drastically improved at x = 0.032. The increases in grain size and hole concentration caused by Bi doping indicate that Bi assists the growth of GaSb thin films. Furthermore, elution tests revealed that Bi doping suppresses the elution of highly toxic Sb under simulated physiological conditions. These findings have the possibility to hasten the development of flexible GaSb-based biomedical and environmental devices with improved safety and lower environmental burden. [ABSTRACT FROM AUTHOR]

Fibroblast growth factor 21 (FGF21) has pharmaceutical potential against obesity-related metabolic disorders, including non-alcoholic fatty liver disease. Since thermal stability is a desirable factor for therapeutic proteins, we investigated the thermal behavior of human FGF21. FGF21 remained soluble after heating; thus, we examined its temperature-induced structural changes using circular dichroism (CD). FGF21 showed inter-convertible temperature-specific CD spectra. The CD spectrum at 100 °C returned to that at 20 °C when the heated FGF21 solution was cooled. Through loop swapping, the connecting loop between β10 and β12 in FGF21 was revealed to be associated with the unique thermal behavior of FGF21. According to surface plasmon resonance (SPR) experiments, in vitro cell-based assays, and model high-fat diet (HFD)-induced obesity studies, heated FGF21 maintained biological activities that were comparable to those of non-heated and commercial FGF21s. Based on sequence comparison and structural analysis, five point-mutations were introduced into FGF21. Compared with the wild type, the heated FGF21 variant displayed improved therapeutic potential in terms of body weight loss, the levels of hepatic triglycerides and lipids, and the degree of vacuolization of liver in HFD-fed mice. [ABSTRACT FROM AUTHOR]

This paper examines key features of the preparation of high-purity Ga from electronic and electrical engineering industry waste. The decrease in the melting point of impurity-containing Ga is assessed thermodynamically in the ideal solution approximation. It is proposed that the purity of gallium in the final crystallization purification step can be monitored via precision measurement of the temperature of the melt with a pyrometer. [ABSTRACT FROM AUTHOR]

Prof. Dr. Panne's ambition as an editor for ABC is to demonstrate that good analytical chemistry is at the core of many fundamental and applied scientific problems and innovations and will contribute to solving the grand challenges of our times. We continue to have a dynamic team of editors at ABC. [Extracted from the article]

This paper describes a detailed study aimed at developing technological principles of the preparation of 99.99995%-pure Cd, Zn, and Te by crystallization purification methods. We have analyzed the thermophysical properties of Cd, Zn, Te, and structural materials of the equipment involved; substantiated the choice of graphite as a crucible material; and determined its engineering features. We have studied impurity distributions in Cd, Zn, and Te in crystallization processes and determined effective performance parameters of the materials refining process in horizontal directional solidification and zone melting steps. The results have allowed us to obtain 99.99995 to 99.99999%-pure Cd, Zn, and Te in terms of 30 major impurities, with a maximum product yield of up to 85%. [ABSTRACT FROM AUTHOR]

Selective isolation of soil Actinobacteria was undertaken to isolate a new class of antibiotics and bioactive molecules. A Streptomyces sp. PSAA01 (= MTCC 13,157), isolated from soil of Eastern Himalaya foothill was cultivated on a large scale for the production of the antimicrobial SM02. It has been found that the maximum amount of SM02 produced while PSAA01 was grown in ISP-2 medium (pH 7.0) for 7 days at 30 °C in shaking (180 rpm) condition. A significant zone of inhibition against Staphylococcus aureus MTCC 96 has been found with the crude cell-free culture media (50 µL) of 7 days grown PSAA01. After the purification and chemical structural characterization, we found that SM02 is a new antimicrobial having 746 dalton molecular weight. The compound SM02 contains pyrimidine moiety in it and is produced by a species of Streptomyces and thus we have named this antibiotic pyrimidomycin. The antimicrobial spectrum of pyrimidomycin has been found to be restricted in Gram-positive organisms with a MIC of 12 µg/mL. SM02 was found active against Mycobacterium sp. and also multi-drug resistant Gram-positive bacteria with similar potency and found to disrupt the bacterial cell wall. Pyrimidomycin also showed significant impairment in the biofilm formation by S. aureus. Furthermore, pyrimidomycin showed synergy with the most used antibiotic like ampicillin, vancomycin and chloramphenicol. Pyrimidomycin did not have cytotoxicity towards human cell lines indicating its limited activity within bacteria. [ABSTRACT FROM AUTHOR]

This research proposes a low-cost and simple operation microfluidic chip to enhance the magnetic labeling efficiency of two ischemic stroke biomarkers: cellular fibronectin (c-Fn) and matrix metallopeptidase 9 (MMP9). This fully portable and pump-free microfluidic chip is operated based on capillary attractions without any external power source and battery. It uses an integrated cellulose sponge to absorb the samples. At the same time, a magnetic field is aligned to hold the target labeled by the magnetic nanoparticles (MNPs) in the pre-concentrated chamber. By using this approach, the specific targets are labeled from the beginning of the sampling process without preliminary sample purification. The proposed study enhanced the labeling efficiency from 1 h to 15 min. The dynamic interactions occur in the serpentine channel, while the crescent formation of MNPs in the pre-concentrated chamber, acting as a magnetic filter, improves the biomarker-MNP interaction. The labeling optimization by the proposed device influences the dynamic range by optimizing the MNP ratio to fit the linear range across the clinical cutoff value. The limits of detection (LODs) of 2.8 ng/mL and 54.6 ng/mL of c-Fn measurement were achieved for undiluted and four times dilutions of MNP, respectively. While for MMP9, the LODs were 11.5 ng/mL for undiluted functionalized MNP and 132 ng/mL for four times dilutions of functionalized MNP. The results highlight the potential use of this device for clinical sample preparation and specific magnetic target labeling. When combined with a detection system, it could also be used as an integrated component of a point-of-care platform. [ABSTRACT FROM AUTHOR]

Proteins are one the most widely studied biomolecules with diverse functions and applications. Aiming at overcoming the current drawbacks of purification processes of proteins, the introduction of ionic liquids (ILs) has been a hot topic of research. ILs have been applied in the creation of aqueous biphasic systems (IL-based ABS), solid-phase extractions through poly(ionic liquid)s (PILs) and supported ionic-liquid phases (SILPs), and in the crystallization of proteins. In this sense, ILs have emerged as solvents, electrolytes or adjuvants, or as supported materials to tune the adsorption/affinity capacity aiming at developing an efficient, cost-effective, sustainable and green IL-based process for protein extraction. This review discusses different IL-based processes in the extraction and purification of proteins in the past years, namely IL-based aqueous biphasic systems (IL-based ABS), solid-phase extractions through PILs and SILPs, and protein crystallization. The type and structure of ILs applied and their influence in the different processes performance are also discussed. [ABSTRACT FROM AUTHOR]

Cutting fluid has cooling and lubricating properties and is an important part of the field of metal machining. Owing to harmful additives, base oils with poor biodegradability, defects in processing methods, and unreasonable emissions of waste cutting fluids, cutting fluids have serious pollution problems, which pose challenges to global carbon emissions laws and regulations. However, the current research on cutting fluid and its circulating purification technique lacks systematic review papers to provide scientific technical guidance for actual production. In this study, the key scientific issues in the research achievements of eco-friendly cutting fluid and waste fluid treatment are clarified. First, the preparation and mechanism of organic additives are summarized, and the influence of the physical and chemical properties of vegetable base oils on lubricating properties is analyzed. Then, the process characteristics of cutting fluid reduction supply methods are systematically evaluated. Second, the treatment of oil mist and miscellaneous oil, the removal mechanism and approach of microorganisms, and the design principles of integrated recycling equipment are outlined. The conclusion is concluded that the synergistic effect of organic additives, biodegradable vegetable base oils and recycling purification effectively reduces the environmental pollution of cutting fluids. Finally, in view of the limitations of the cutting fluid and its circulating purification technique, the prospects of amino acid additive development, self-adapting jet parameter supply system, matching mechanism between processing conditions and cutting fluid are put forward, which provides the basis and support for the engineering application and development of cutting fluid and its circulating purification. [ABSTRACT FROM AUTHOR]

Chemical gardens are an example of a chemobrionic system that typically result in abiotic macro-, micro- and nano- material architectures, with formation driven by complex out-of-equilibrium reaction mechanisms. From a technological perspective, controlling chemobrionic processes may hold great promise for the creation of novel, compositionally diverse and ultimately, useful materials and devices. In this work, we engineer an innovative custom-built liquid exchange unit that enables us to control the formation of tubular chemical garden structures grown from the interface between calcium loaded hydrogel and phosphate solution. We show that systematic displacement of phosphate solution with water (H2O) can halt self-assembly, precisely control tube height and purify structures in situ. Furthermore, we demonstrate the fabrication of a heterogeneous chemobrionic composite material composed of aligned, high-aspect ratio calcium phosphate channels running through an otherwise dense matrix of poly(2-hydroxyethyl methacrylate) (pHEMA). Given that the principles we derive can be broadly applied to potentially control various chemobrionic systems, this work paves the way for fabricating multifunctional materials that may hold great potential in a variety of application areas, such as regenerative medicine, catalysis and microfluidics. Chemobrionic materials with applications in tissue engineering can be grown at the interface of calcium and phosphate solutions, however, controlling their dimensions and purity can be difficult. Herein, a flow device allows control of the height and in situ purification of chemical gardens, which can be encased in a photoset hydrogel for subsequent use. [ABSTRACT FROM AUTHOR]

The methods used in the nuclear industry for reprocessing liquid radwaste, including salt concentrates from evaporator plants at nuclear power plants, are discussed. The results of a technical-and-economic feasibility study of the three methods used for the processing of salt concentrates are presented: cementing, deep evaporation, and ion-selective purification. It is shown that the ion-selective purification method is the most effective one in comparison with the first two, as it effects significant volume reduction of mid-level class-3 radioactive waste transferred for disposal. Recommendations are made for changing the technology used for management of liquid waste at next-generation nuclear power plants, including separate collection and creation of local schemes for their processing and conditioning. [ABSTRACT FROM AUTHOR]

The catalytic activity of hexagonal boron nitride (hBN) is not yet well understood, but it seems to be related to hBN hydroxylated sites. A good understanding of those sites and how they are produced is a key step to reveal the true nature of hBN catalytic activity. Here, we report a set of thermal treatments to produce a diversity of hydroxylated sites, as well as a method to remove the boric acid produced by hBN decomposition. We found that some of the boric acid dehydrates on the surface of hBN to produce a borated hBN (hBNO) characterized by an FTIR peat at 1090 cm−1 and an XRD shift due to the variation in the planar distance. We also showed that when characterizing the thermal treated hBN, the storage of the sample changed the borate's hydration degree and modified both the XRD pattern and the FTIR spectrum. When stored in a humid environment, boric acid peaks are visible, but they are not present if samples are stored in a dry place. The methods established here are a solid basis for the manufacture, purification and characterization of hBN by thermal treatments, showing how the process can be designed to generate various functional groups on its surface. [ABSTRACT FROM AUTHOR]

The green microalga Haematococcus pluvialis has been widely studied due to its capacity to accumulate great amounts of astaxanthin, a high-value carotenoid with biological activities. In the present work, two green compressed fluid–based processes, pressurized liquid extraction (PLE) and supercritical antisolvent fractionation (SAF), are integrated to obtain an astaxanthin-enriched extract from this microalga. PLE was carried out using pressurized ethanol as solvent, for 20 min, at 10 MPa, and 50 °C as extraction temperature. Subsequently, the obtained extract was processed by SAF to further purify the carotenoid fraction. The SAF process was optimized using a 3-level factorial experimental design and considering three experimental variables: (i) CO2 pressure (10–30 MPa), (ii) percentage of water in the PLE extract (20–50%), and (iii) PLE extract/supercritical-CO2 flow rate ratio (0.0125–0.05). Total carotenoid content was evaluated in both extracts and raffinates. Best results were obtained at 30 MPa, 0.05 feed/SC-CO2 mass flow rate, and 20% (v/v) of water in the feed solution, achieving values of 120.3 mg g−1 carotenoids in extract (in the SAF extract fraction), which were significantly higher than those obtained in the original PLE extract. In parallel, a new fast two-dimensional comprehensive liquid chromatography (LC×LC) method was optimized to get the full carotenoid profile of these extracts in less than 25 min. This is the first time that the use of a C30 column is reported in an on-line LC×LC system. [ABSTRACT FROM AUTHOR]

Impurities are of crucial interest in optoelectronic devices as they affect carrier lifetimes and electrical properties. In view of that, it is important to incorporate certain processing steps to reduce impurities effect on final devices. The aim of this work is to enhance silicon carbide SiC purity for silicon passivation. Low cost method of SiC purification is presented. This method combines three main steps consisting of formation of porous silicon carbide layers by acid vapor etching followed by a photo-thermal annealing at different temperatures. Finally, obtained SiC powder was subject to a chemical treatment to remove porous SiC layer. Effect of gettering temperature on purification efficiency was evaluated by inductively coupled plasma atomic emission spectrometry (ICP-AES). The gettering experiment was performed at 800–950 °C, and optimum results were obtained at 950 °C. SiC purity is improved from 3 N (99.977%) to 5 N (99.999%) with an impurity removal efficiency of 96.56%. Purified SiC was used as a target to synthesize SiC layers using pulsed laser deposition technique (PLD) for optoelectronic devices. The use of intrinsic amorphous silicon carbide (a-SiC) passivating layers was investigated especially by photoconductivity decay technique. Improved SiC target purity leads to a significant enhancement of a-SiC passivating properties attributed to the surface recombination velocity decrease. Electrical properties of a-SiC/c-Si(p) were also studied using I-V and C-V techniques. [ABSTRACT FROM AUTHOR]

Due to widespread droughts and population increase, the rapid and sustainable purification of contaminated water is of major interest to human beings. Toward this end, this paper reports a handheld and efficient purification system using maskless micro/nanofabrication techniques. A porous polymer membrane decorated with nanomaterials was tailored to physically filter pollutants in contaminated water. To create the porous polymer membrane, curable polymer and black sugar powder were used for a facile and cost-effective fabrication method. The black sugar particles linked in cured polymer were selectively dissolved in hot water, forming micro-sized pores for filtering out pollutants. The nanowires were hydrothermally grown onto the porous membrane to further improve the purification performance by capturing finer pollutants between nanowires. The combination of nanowires and 50-wt% concentration of black sugar particle, forming a porosity of ~ 27.71% showed the minimum residual rate (i.e., weight of pollutants in purified water) of 0.981 mg/ml. This study supports the use of hierarchical porous membrane for the efficient and sustainable purification of contaminated water within a short period time. [ABSTRACT FROM AUTHOR]

We developed a sample preparation method for the determination of polybrominated diphenyl ethers (PBDEs) with from one to ten bromine atoms in samples of feed and food products containing approximately 0.5 g of animal fat or vegetable oil. The method involves gas chromatography with high-resolution mass spectrometry or tandem mass spectrometry. A possibility of using various reagents for the purification of extracts by chemical reactions and fractionation is studied. The physicochemical properties of PBDEs and polychlorinated biphenyls (PCBs) have significant differences, and to determine the full range of PBDEs, it is necessary to use other methods of sample preparation than in the case of PCBs. The conditions selected for the purification of extracts in a column filled with potassium silicate, Florisil, and silica impregnated with sulfuric acid and for their fractionation using activated neutral alumina ensure the PBDE recoveries of at least 75%. Purification of the extracts can be carried out without the use of chlorinated organic solvents. Applied aspects of instrumental analysis and measurement quality assurance are also described. [ABSTRACT FROM AUTHOR]

A promising method was proposed for the first time for purification of animal bone tissue fragments from high-molecular weight compounds in biphase media containing high-pressure CO2 (solutions of carbonic and peroxycarbonic acids). The efficiency of this purification was confirmed by SEM and IR spectroscopy. It turned out that, during the exposure of bone fragments in solutions of carbonic and peroxycarbonic acids at high CO2 pressure, mineral phase components of bone tissue are also extracted, which can be used to obtain highly dispersed hydroxyapatite particles upon extract reprecipitation. The structure and composition of the extracts were investigated by X-ray diffraction and scanning electron microscopy (SEM). [ABSTRACT FROM AUTHOR]

This work presents a new and simple procedure for the shape selective purification of gold nanorods from a mixture of rods and spheres. Previously reported methods were time-consuming and revealed several drawbacks such as low yields and difficulty to recover the purified nanoparticles. Additionally, they were mostly applied to high aspect ratio (AR) nanorods. Our process is based on only simple and short centrifugation steps in order to precipitate specifically gold nanospheres. Samples containing low AR nanorods (AR < 6) were selected to perform the purification process. The supernatant content was followed by UV-Visible absorption spectroscopy after each centrifugation step. Then, transmission electron microscopy (TEM) allowed extract the purification efficiency thanks to shape analyses performed on more than 1000 nanoparticles. These results showed that our centrifugation process was applied successfully to three sizes of nanorods (2.4, 3.7, and 5.3). High purification yields of 72 and 78% were attained for AR = 3.7 and AR = 5.3 nanorods, respectively. [ABSTRACT FROM AUTHOR]

We have proposed and tested a combined process for ultrapurification of monoisotopic S and S sulfur, which comprises thermochemical treatment of sulfur vapor on silica and ceria packing, melting with aluminum, and distillation. The impurity composition of the purified sulfur has been determined by atomic emission and IR spectroscopy. We have obtained monoisotopic S and S sulfur samples comparable in chemical purity to high-purity sulfur of natural isotopic composition. [ABSTRACT FROM AUTHOR]

We have studied the wetting behavior of molten germanium on silica ceramics and amorphous silica coatings in vacuum at a pressure of 1 Pa and a temperature of 1273 K. The results demonstrate that the wetting of rough surfaces of ceramic samples and coatings by liquid Ge is significantly poorer than that of the smooth surface of quartz glass. The contact angle of polished glass is ~100°, and that of the ceramics and coatings increases from 112° to 137° as the total impurity content of the material decreases from 0.120 to 1 × 10 wt %. Using experimental contact angle data, we calculated the work of adhesion of molten Ge to the materials studied. Its value for the surface of the ceramics and coatings decreases from 0.45 to 0.20 J/m with decreasing impurity content, whereas the work of adhesion to a smooth glass surface is 0.55 J/m. We have fabricated fused silica test containers coated with high-purity amorphous silica. Using horizontal zone refining, we obtained germanium samples with a carrier concentration difference on the order of 10 cm. [ABSTRACT FROM AUTHOR]

Design of a flat-chamber type of electrobaromembrane device and procedure for calculating permeate flow rate and increased effective membrane area are developed for cleaning chemical, engineering, and food industry process solutions. [ABSTRACT FROM AUTHOR]

Waste-generation schemes for β-lactam cephalosporin production were compared. It was shown that effluents from chemical transformation and purification steps are the most ecologically polluted and hazardous. Therefore, the issue of reduced environmental impact must be resolved first for these process steps. In general, the technogenic load from cephalothin sodium salt production was greater than that from cephalexin monohydrate production. [ABSTRACT FROM AUTHOR]

Saponins are secondary metabolites that are abundant and diversified in echinoderms. Mass spectrometry is increasingly used not only to identify saponin congeners within animal extracts but also to decipher the structure/biological activity relationships of these molecules by determining their inter-organ and inter-individual variability. The usual method requires extensive purification procedures to prepare saponin extracts compatible with mass spectrometry analysis. Here, we selected the sea star Asterias rubens as a model animal to prove that direct analysis of saponins can be performed on tissue sections. We also demonstrated that carboxymethyl cellulose can be used as an embedding medium to facilitate the cryosectioning procedure. Matrix-assisted laser desorption/ionization (MALDI) imaging was also revealed to afford interesting data on the distribution of saponin molecules within the tissues. We indeed highlight that saponins are located not only inside the body wall of the animals but also within the mucus layer that probably protects the animal against external aggressions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Age of individual uranium-plutonium (U/Pu) mixed particles with various U/Pu atomic ratios (1-70) were determined by inductively coupled plasma mass spectrometry. Micron-sized particles were prepared from U and Pu certified reference materials. The Pu reference was stored for 4-6 years since the last purification (July 14, 2008). The Pu purification age was obtained from the Am/Pu ratio which was calculated from the product of three measured ratios of Pu and Am isotopes in the eluted fractions. These ratios were measured by a high-resolution inductively coupled plasma mass spectrometer equipped with a desolvation system. Femto-gram to pico-gram quantities of Am, U, and Pu in a sample solution were sequentially separated on a small anion-exchange column. The Am/Pu ratio was accurately determined by spiking pure Am into the sample solution. The average determined age for the particles for the five independent U/Pu ratios was in good agreement with the expected age with high accuracy (difference age 0.27 years) and high precision (standard deviation 0.44 years). The described analytical technique can serve as an effective tool for nuclear safeguards and environmental radiochemistry. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

We have investigated the mechanism for the reversible addition of ethylene to a periodic 2D network of square-planar nickel centers ([Ni(SC)]) using density functional theory. The mechanism is analogous to that for homogeneous olefin binding to metal bis(dithiolene) complexes. We considered periodic boundary calculations (PBC) as well as clusters containing up to 12 nickel atoms using a screened hybrid density functional to obtain accurate reaction barriers. Several different products were analyzed. The lowest-energy route begins with the addition of ethylene across the nickel-sulfur bond, which has previously not been considered for this system. The effect of the addition of several alkene molecules simultaneously on the surface was investigated to determine the potential efficiency of this material. This material is a candidate for alkene purification as it exhibits similar reactivity to its molecular analog in terms of the relative stability of products, energy barriers, and molecular efficiency while also providing the intrinsic technical benefits of heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

The leaf of Magnolia officinalis is abundant in natural resources as a novel potential antioxidant and has great commercial value. In this study, the contents of total phenolics, total flavonoids, magnolol and honokiol in different solvent extracts (acetone, methanol and water) were measured. Meanwhile, the antioxidant activity of extracts from M. officinalis leaves were evaluated using 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay, 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt free radical scavenging assay, FRAP assays and β-carotene/linoleic acid system. In addition, the correlation between the antioxidant activity and the contents of the active compounds was analyzed. Experimental results indicated that three extracts exhibited antioxidant effects in a concentration-dependent manner, and acetone extracts had the highest antioxidant activity, next methanol and water. There was an intimate relativity between the contents of magnolol and honokiol in different solvent extracts and the antioxidant capability of them. So the magnolol and honokiol of M. officinalis leaves as a representative of the active compounds were extracted and purified by using the macroporous resin column. The purity of depurated sample could reach 82.6 %, which indicates the M. officinalis leaves have the potential to substitute the production of magnolol and honokiol in M. officinalis. The results of this study can provide theoretical and technical references for the reasonable use of the M. officinalis leaves and alleviate the shortage of M. officinalis resources. [ABSTRACT FROM AUTHOR]

A three-stage linear gradient strategy using reverse-phase high-performance liquid chromatography (HPLC) was optimized for rapid, high-quality, and simultaneous purification of the lipopeptide isoforms of iturin, fengycin, and surfactin, which may differ in composition by only a single amino acid and/or the fatty acid residue. Matrix-assisted laser desorption ionization time-of-flight tandem mass spectrometry (MALDI-TOF-MS/MS) was applied to detect the lipopeptides harvested from each reversed-phase HPLC peak. Amino acid analysis based on phenyl isothiocyanate derivatization was further used for confirmation of the amino acid species and molar ratio in a certain HPLC fraction. By this MALDI-TOF-MS/MS coupled with amino acid analysis, it was revealed that iturin at m/ z 1,043 consists of a circular Asn-Tyr-Asn-Gln-Pro-Asn-Ser peptide and C β-OH fatty acid. Surfactin homologs from Bacillus subtilis THY-7 at m/ z 1,030, 1,044, 1,058, and 1,072 possess a circular Glu-Leu-Leu-Val-Asp-Leu-Leu peptide and the β-OH fatty acid with a different length (C-C). Fengycin species at m/ z 1,463 and 1,477 are homologs possessing the circular peptide Glu-Orn-Tyr-Thr-Glu-Ala-Pro-Gln-Tyr-Ile linked to a C or C γ-OH fatty acid, whereas fengycin at m/ z 1,505 contains a Glu-Orn-Tyr-Thr-Glu-Val-Pro-Gln-Tyr-Ile sequence with a Val instead of Ala at position 6. The method developed in this work provided an efficient approach for characterization of diverse lipopeptide isoforms from the iturin, fengycin, and surfactin families. [ABSTRACT FROM AUTHOR]

A design diagram and simple asymptotic formulas are proposed for the supporting frame of a membrane device consisting of two covers in the form of open toroidal shells that mate with a ring along the outer perimeter, and an opening with a circular plate around the inner perimeter. The diagram and formulas make it possible to estimate the stress-strain state of basic components of the cover: toroidal shell, circular plate, and ring. An example of the procedure used to calculate the strength and stiffness of the cover of the device is given. [ABSTRACT FROM AUTHOR]

This paper addresses the preparation, purification (removal of oxygen-containing impurities), and applications of fluoride glasses, with particular attention to the preparation of modified glasses for extending their transmission window. [ABSTRACT FROM AUTHOR]

Standard enthalpies of formation of ternary phases in the Cu-Ni-Sn system were determined along sections at 25, 41 and 45.5 at.% Sn applying tin solution drop calorimetry. Generally, the interaction of Ni with Sn is much stronger than that of Cu with Sn. Along all sections the enthalpy of formation changes almost linearly with the mutual substitution of Cu and Ni within the respective homogeneity ranges. Thus no additional ternary interaction promoting the formation of further Cu-Ni-Sn phases can be assumed. The results are discussed and compared with literature values relevant to this system. [ABSTRACT FROM AUTHOR]

This paper describes ultrapurification of isotopically enriched calcium and molybdenum compounds and CaMoO calcium molybdate growth charge in order to remove radioactive uranium, thorium, and radium impurities. CaMoO single crystals grown from such charges are needed for the fabrication of scintillator elements of the cryogenic detector for the AMoRE project: a search for Mo neutrino-less double-beta decay. [ABSTRACT FROM AUTHOR]

Serine protease from kesinai leaves was purified for the first time by a surfactant-polymer aqueous micellar two-phase system. The effectiveness of different types and concentrations of non-ionic surfactants (Pluronic series and X-114) on the partitioning behaviour of the protease was evaluated. The results showed that the enzyme preferentially partitioned into the bottom surfactant-rich phase, while the hydrophilic amino acid preferred the top aqueous phase. This distribution of the enzyme is due to the hydrophobic interaction of the serine protease with the hydrophobic lid of the micelle core in the bottom phase. The influence of different types of salts (KSO, KHPO, KCl and KNO) on the purification and selectivity of the enzyme was determined. The protease partitioning in the bottom phase increased in the presence of KNO, which confirmed that the salt was able to improve the protein solubility in bottom phase and increase the hydrophobic interaction between the two phases. In addition, the protease from the bottom phase was re-extracted to a new aqueous phase solution to remove and recycle the surfactant. Addition of potassium thiocyanate led to the partitioning of the enzyme in top aqueous phase due to high ionic strength of SCN, which forced the lighter micellar phase toward the upper position of the system. A high purification factor (10.3) and yield of 92 % of the enzyme were achieved in a solution of 31 % of Pluronic L61 using 0.3 % KNO and 50 % crude feedstock at pH 7.0. [ABSTRACT FROM AUTHOR]

Saponins are widely distributed in the plant kingdom and have been shown to be active components of many medicinal herbs. In this study, a two-dimensional purification method based on reversed-phase liquid chromatography coupled with hydrophilic interaction liquid chromatography was successfully applied to purify saponins from leaves of Panax notoginseng. Nine saponin reference standards were used to test the separation modes and columns. The standards could not be resolved using C columns owing to their limited polar selectivity. However, they were completely separated on a XAmide column in hydrophilic interaction liquid chromatography mode, including two pairs of standards that were coeluted on a C column. The elution order of the standards on the two columns was sufficiently different, with a correlation coefficient between retention times on the C and XAmide columns of 0.0126, indicating good column orthogonality. Therefore, the first-dimension preparation was performed on a C column, followed by a XAmide column that was used to separate the fractions in the second dimension. Fifty-four fractions were prepared in the first dimension, with 25 fractions rich in saponins. Eight saponins, including two pairs of isomeric saponins and one new saponin, were isolated and identified from three representative fractions. This procedure was shown to be an effective approach for the preparative isolation and purification of saponins from leaves of P. notoginseng. Moreover, this method could possibly be employed in the purification of low-content and novel active saponins from natural products. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

N-Protected á-amino acids, prepared from benzoyl chlorides, KSCN and á-amino acids, were used as the acid component in the Passerini reaction, in an ionic liquid, to produce functionalized a-acyloxythioamides in 59-95% yields. The work-up procedure was fairly simple and the products did not require further purification. [ABSTRACT FROM AUTHOR]

The physicochemical modeling of the behavior of impurities in the course of their preconcentration by the chemical distillation of the sample matrix consisting of granules of a solid solution of impurities in bismuth oxide was carried out. It was supposed that the distillation process is conducted in a kinetic mode. The results of calculations by the model are compared with the earlier results of modeling of the behavior of impurities in distilling a heterophase sample consisting of matrix (bismuth oxide) granules and granules of impurity oxides. The experimental data and results of calculations by the model agree well. [ABSTRACT FROM AUTHOR]

Eight new acidochromic dyes have been synthesised that can be used for optically monitoring pH in the range from 3 to 12. Their corresponding p K a values have been both measured and calculated theoretically by means of density functional theory. The synthesis of these new dyes is facile without the need for chromatographic purification. The dyes can be covalently linked to polymers containing hydroxyl functions such as cellulose, polyurethane hydrogel, and hydroxyalkyl methacrylate. The resulting sensor layers exhibit significant colour changes both in the UV and in the visible spectral range. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Characterization of humic substances (HS) in environmental samples generally involves labor-intensive and time-consuming isolation and purification procedures. In this paper, the development of an automated system for HS isolation and purification is described. The novelty of the developed system lies in the way the multiple liquids and columns used in the isolation/purification procedure are handled in both forward and back-elution mode by solenoid valves. The automated procedure significantly reduces the total throughput time needed, from 6–7 days to 48 h, and the amount of labor to obtain purified HS for further characterization. Chemical characterization of purified HS showed that results were in good agreement with previously published values for HS from a variety of sources, including the IHSS standard HS collection. It was also shown that the general properties of HS were consistent among the different source materials (soil, waste, aquatic) used in this study. The developed system greatly facilitates isolation and characterization of HS and reduces the risk of potential (time-dependent) alteration of HS properties in the manual procedure. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Using computer simulation, we have studied the effects of principal process parameters on the yield of a substance being purified to the desired purity level in a middle-vessel packed batch distillation column, with examples for isotopically pure silane. The results indicate that there are the optimal column height, reflux rate, and charge weight, which minimize the loss of the substance being purified. [ABSTRACT FROM AUTHOR]

Abstract  In the present study a method to detect and identify the integration site of a foreign DNA sequence, e.g., a horizontally transferred DNA sequence is described. For this purpose a model was developed to simulate a tissue sample. The method includes four main steps; (a) digestion of DNA, (b) ligation of adaptors to the digestion sites, (c) solid phase purification and (d) PCR amplification. Solid phase purification of the amplified targets markedly improved the sensitivity of the method and the described method was found to be able to detect approximately two copies of a target sequence in a DNA background of 25 ng, corresponding to a single integration site in a single dividing cell in a tissue sample. The model consists of salmon and soy DNA, where the soy DNA simulates DNA from feed taken up from the gastrointestinal tract of salmon. [ABSTRACT FROM AUTHOR]

Purification methods for proteomics samples are of crucial concern for improving the quality of the sample delivered to the mass spectrometer. They constitute the link between the mass spectrometer and protein processing and peptide isolation steps that usually require solvents, buffers, or detergents completely incompatible with MS-analysis conditions. This work describes three new clean-up procedures using synthetic membranes and polymer media and compares them with standard procedures. The efficiency of each of the purification procedures was studied via application to four standards and two membrane proteins. This work highlights the importance of versatility in sample preparation, especially for MS-based proteomic investigations. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Three hundred and thirty two bacterial colonies were isolated from soil contaminated by an oil spill. All the bacteria were cultured in a liquid medium individually, and the surface tensions of the media were compared. The bacterium whose culture medium had the lowest surface tension was identified as Pseudomonas sp. G11. A biosurfactant was produced by cultivation of the Pseudomonas sp. G11 in the LB media. For extraction of the biosurfactant, two solvent systems were used ( n-hexane and a 2:1 (v/v) mixture of chloroform/MeOH), and the results were compared. Various experimental conditions (solvent composition, flow rate, etc.) were tested to optimize the analysis of the biosurfactant by asymmetrical flow field-flow fractionation (AsFlFFF). The biosurfactant was successfully separated from the culture medium by AsFlFFF when pure water was used as the carrier. From the retention data, the hydrodynamic diameter ( d H) and molecular weight ( M) of the biosurfactant were determined by AsFlFFF. The molecular weight was determined by using pullulans as the calibration standards. The d H and M were 49 nm and 2.3 × 105 Da when extracted with n-hexane, and 39 nm and 1.13 × 105 Da when extracted with the 2:1 mixture of chloroform/MeOH, respectively. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Dense boron samples with a glassy structure have been prepared for the first time by high-pressure sintering of amorphous boron powder at temperatures from 750 to 1100 K. Analysis of the mechanical properties of boron samples sintered at pressures from 2 to 8 GPa and different temperatures indicates that sintering proceeds most effectively near 750 K. Purification of amorphous boron in water is shown to be effective in removing products of boron oxidation in air. [ABSTRACT FROM AUTHOR]

The increasing demands for indium in recent years require high purity indium as raw materials. Physical-chemical purification and electrorefining have been performed to obtain 6N high purity indium. Indium is smelted by using NaOH, NaCl and NaNO3 for 20 min at 400°C, the removing rate of Sn, Zn, Al reaches 40, 60 and 37% respectively. The removing rate of Cd is 90–95% and that of Tl reaches 40–60% when indium is smelted for 10 min by 20% glycerin solution of KI and I2 at 180°C. When indium metal is vacuum refined in two stages: 800–900°C for 2 h and 950–1050°C for 2 h, the major impurity elements, Pb, Zn, and Bi, are effectively removed. When indium is electrolytic refined in In2(SO4)3-H2SO4 system, in which indium content is 60–80 g/L, pH 2.0–3.0, current density 50–80 A/m2, the content of impurities can be dropped and the product of indium reaches 99.9999%. [ABSTRACT FROM AUTHOR]

It is shown that the modular technology of high-purity hycirofluoric acid can be optimized along two lines: replacement of the module for the chemical treatment of the acid by a more efficient one and the introduction of a hydroionic convection module for reducing the concentration of ionic impurities. [ABSTRACT FROM AUTHOR]

The goal of this study was to identify and biochemically characterize a novel hyperthermostable keratinase from microorganisms for feather waste degradation. Here, a hyperthermophilic Geoglobus acetivorans keratinase (GacK) gene was chosen based on a search of a sequence database. The selected GacK gene was synthesized, cloned, and successfully expressed without a signal peptide in the E. coli system. A monomer of approximately 58 kDa was obtained in a soluble form and purified. The recombinant GacK displayed the highest activity at an optimum temperature of 100 °C and a pH of 10. The hyperthermostable GacK enzymatic performance remained high even after incubation in nonionic surfactants and the chelating agent EDTA. The residual and keratinolytic activities of GacK, as determined with azocasein and keratin azure used as substrates, remained significantly greater than 80% at 130 °C for 7 h. The kinetic parameters Km and Vmax for azure keratin were 0.41 mg/ml and 875.14 unit/mg, respectively, while those for azocasein were 1.51 mg/ml and 505.32 unit/mg, respectively. The results suggest that the enzyme is among the most hyperthermostable keratinases. Because of its enzymatic characteristics to degrade keratin azure at high temperatures, GacK may potentially be utilized in future industrial applications. [ABSTRACT FROM AUTHOR]

Membrane protein purification is a laborious, expensive, and protracted process involving detergents for its extraction. Purifying functionally active form of membrane protein in sufficient quantity is a major bottleneck in establishing its structure and understanding the functional mechanism. Although overexpression of the membrane proteins has been achieved by recombinant DNA technology, a majority of the protein remains insoluble as inclusion bodies, which is extracted by detergents. Detergent removal is essential for retaining protein structure, function, and subsequent purification techniques. In this study, we have proposed a new approach for detergent removal from the solubilized extract of a recombinant membrane protein: human phospholipid scramblase 3 (hPLSCR3). N-lauryl sarcosine (NLS) has been established as an effective detergent to extract the functionally active recombinant 6X-his- hPLSCR3 from the inclusion bodies. NLS removal before affinity-based purification is essential as the detergent interferes with the matrix binding. Detergent removal by adsorption onto hydrophobic polystyrene beads has been methodically studied and established that the current approach was 10 times faster than the conventional dialysis method. The study established the potency of polystyrene-based beads as a convenient, efficient, and alternate tool to dialysis in detergent removal without significantly altering the structure and function of the membrane protein. [ABSTRACT FROM AUTHOR]

The article focuses on the report with regards to the catalytic reaction that transfer allyl groups into activated imines. It states that the catalytic reaction can deliver homoallylic alcohols from carbonyls, and homoallylic amine derivatives from activated imines, which can also make molecular complexity. Furthermore, it says that the use of chiral auxiliaries is common in effective allylation processes, and need substantial effort in purifying reaction mixture's desired product.