Acetone

The optical properties of four currently ysed and two recently introduced maxillofacial prosthetic materials were evaluated after the materials were subjected to the following seven environmental variables: natural weathering; normal aging; two types of adhesives; two types of cleaning agents; and cosmetics. Optical density and color changes were evaluated. The currently used silicones Silastic 4-4210 and Silastic 4-4515, Medical Adhesive type A material, and polyurethane all showed more changes in color and optical density than the newly introduced silicone A-102 material. (J PROSTHET DENT 1992;68:820-3.)

A series of 25 sera were assayed with the proposed system, in duplicate, each day for five days; the standard deviation of the results was ± 2.5 mg/dl. Correlation results for 33 sera assayed with the proposed system and with an automated o-toluidine one

Human health risk assessment has begun to depart from the traditional methods by replacement of the default assessment factors by more reasonable, data-driven, so-called chemicalspecific adjustment factors (CSAFs). This study illustrates a scheme for deriving CSAFs in the general and occupationally exposed populations by quantifying the intraspecies toxicokinetic variability in surrogate dose using probabilistic methods. Acetone was used as a model substance. The CSAFs were derived by Monte Carlo simulation, combining a physiologically based pharmacokinetic model for acetone, probability distributions of the model parameters from a Bayesian analysis of male volunteer experimental data, and published distributions of physiological and anatomical parameters for females and children. The simulations covered how factors such as age, gender, endogenous acetone production, and fluctuations in workplace air concentration and workload influence peak and average acetone levels in blood, used as surrogate doses. According to the simulations, CSAFs of 2.1, 2.9, and 3.8 are sufficient to cover the differences in surrogate dose at the upper 90th, 95th, and 97.5th percentile, respectively, of the general population. However, higher factors were needed to cover the same percentiles of children. The corresponding CSAFs for the occupationally exposed population were 1.6, 1.8, and 1.9. The methodology presented herein allows for derivation of CSAFs not only for populations as a whole but also for subpopulations of interest. Moreover, various types of experimental data can readily be incorporated in the model.

The aim of this study was to compare the resistance of endodontically treated teeth with intraradicular retainer different amounts of remaining coronal structure. Fifty freshly extracted maxillary canines were endodontically treated and randomly assigned to five groups (n=10), as follows: group 1 (control) = teeth with custom cast post and core; group 2 = teeth without remaining coronal structure; group 3, 4 and 5 = teeth with 1 mm, 2 mm and 3 mm of remaining coronal structure, respectively. All specimens in groups 2 to 5 were restored with prefabricated post and resin core. The teeth were embedded in acrylic resin and the fracture strength was measured on a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed statistically by one-way analysis of variance and Tukey's test. There was no significant differences (p>0.05) between the control group and group 2, and between groups 3, 4 and 5 (p>0.05). Control group and group 2 had significantly higher resistance strength than groups 3, 4 and 5 (p<0.00001). The findings of this study showed that teeth without remaining coronal structure had significantly higher fracture strength than those with remaining coronal structure (1 mm, 2 mm and 3 mm). When the dental crown was not completely removed, the amount of remaining coronal dentin did not significantly affect the fracture strength of endodontically treated teeth with intraradicular retainer.

Photochromic compounds exhibit reversible transition between closed and open isomeric forms upon irradiation accompanied by change in their color. The two isomeric forms differ not only in absorption spectra, but also in various physical and chemical properties and find applications as optical switching and data storage materials. In this contribution we apply Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) to predict the equilibrium geometry and absorption spectra of a benchmark set of diarylethene based photochromic compounds in open and closed forms (before and after photocyclization). Comparison of the calculated Bond Length Alternation parameters with those available from the X-ray data indicates M05-2x functional to be the best method for geometry optimization when basis set includes polarization functions. We found M05 functional accurately predicts the maximum absorption wavelength when solvent is taken into account. We recommend combined theory level TD-M05/...

Background: Many volatile organic compounds are present in exhaled breath and may represent by-products of endogenous biological processes. Ethanol is produced via alcoholic fermentation of glucose by gut bacteria and yeast, while acetone derives from oxidations of free fatty acids, influenced by glucose metabolism. We hypothesized that the integrated analysis of breath ethanol and acetone would provide a good approximation of the blood glucose profile during a glucose load.

Background and aims Ethanol- or 2-propanol-containing disinfectant agents are widely used in medical practice, particularly in the surgical environment. It was the primary objective of this phase I study to comparatively investigate the transdermal resorption of ethanol and 2-propanol within 1 h after dermal application of the two agents as single preparations and a commercial product containing both alcohols in combination, respectively. The secondary objective was to examine whether a mutual influence of the two alcohols in combination exists. Materials and methods Following the double-blind, randomized, three-times cross-over design for this clinical trial, 20 ml of three different alcohol-containing disinfectants were applied on a 200-cm2 gauze swab on skin areas, identical in size and location, of 14 healthy volunteers for 10 min to investigate the absorption rate of ethanol and 2-propanol with special focus on the question whether the two alcohols might influence each other’s absorption rate when being applied in combination. Results No clinically relevant enhancement of dermal absorption, with respect to ethanol and 2-propanol, could be observed within 1 h after application, neither when used as single preparations, nor in combination. Conclusion Therefore, the use of ethanol- and 2-propanol-containing disinfectants in the medical environment can be considered as safe.

Xylitol was produced by Candida guilliermondii by fermentation of sugarcane bagasse hemicellulosic hydrolysate. Undesirable impurities were extracted from the broth using either ethyl acetate, chloroform or dichloromethane. The best results on clarification of the broth without xylitol loss were obtained with ethyl acetate. When ethanol, acetone or tetrahydrofuran were used for precipitation of impurities, only tetrahydrofuran clarified the fermented broth, but a high xylitol loss (~30%) was observed.

The AgNOR technique has been used extensively in studies investigating the possibility that the numbers and appearances of the intranuclear structures stained are markers of malignancy. The method has the advantage of being applicable to many different types of histological material, including paraffin-embedded tissue. However, it has been suggested that the visualization of AgNORs is dependent on the type and time of fixation employed. This study set out to measure this effect with the following commonly-used fixatives: acetone, absolute ethanol, methanol, Carnoy's fluid, Bouin's fluid, 4% glutaraldehyde, 10% neutral buffered formalin and i0% formol-saline. Both frozen sections and blocks of flesh tonsil were fixed for varying times, the blocks of tissue then being processed routinely. With the frozen sections AgNORs were easier to discern than in sections of paraffin-embedded tissue, and more intranucleolar AgNORs were visible when alcoholic fixatives were used than with aldehyde fixation. The effects of different fixatives on AgNOR appearance in paraffin sections is, however, more complex. Despite the variation caused by different fixatives, AgNORs could be demonstrated adequately with all the fixatives studied. It is concluded that fixation is not a limitation to the study of AgNORs provided that the time and type of fixative is controlled.

Microcrystals of megestrol acetate (MA), a poorly water-soluble drug, were successfully prepared using an antisolvent precipitation technique for improving the dissolution rate. The effective hydrophilic polymers and surfactants used were screened for their abilities to produce smaller particle sizes. Raw micronized MA and processed MA microcrystals were ranked by the Student-Newman-Keuls test in order of increasing particle size and SPAN values as follows: processed MA microcrystals in the presence of polymer and surfactant (mean diameter 1048 nm) < processed MA microcrystals in the presence of polymer (1654 nm) < processed MA microcrystals in the absence of polymer and surfactant (3491 nm) < raw micronized MA (4352 nm). The order of BET surface area was reversely ranked. Processed MA microcrystals in the presence of polymer and surfactant slightly decreased crystallinity and altered crystal habit and preferred orientation without change in polymorph. In addition, the dissolution properties of the processed MA microcrystals in the presence of polymer and surfactant were significantly enhanced as compared to that of the raw micronized MA. This effect is mainly due to a reduction in particle size resulting in an increased surface area. Therefore, it was concluded that the antisolvent precipitation technique in mild conditions could be a simple and useful technique to prepare poorly water-soluble drug particles with reduction in particle size, a narrow particle size distribution and enhanced dissolution properties.

The authors have previously isolated a solvent tolerant bacterium, strain GT, (T = type strain) capable to convert acetone-butanol bioprocess residues into poly-β-hydroxybutyrate. Strain GT was initially identified as Alcaligenes spp by standard bacteriological tests. In this study the taxonomic position of the bacterium was investigated in detail. The 16S rDNA sequence analysis, the G + C content of DNA (56 mol%) and the presence of ubiquinone Q-8 confirmed strain GT as a representative of the genus Alcaligenes. In the polyamine pattern of the bacterium putrescine and cadaverine were detected, but only trace amounts of 2-hydroxyputrescine. The extremely low content of 2-hydroxyputrescine is remarkable, since this unique diamine is a common marker for β-proteobacteria. Phylogenetic analyses of 16S rDNA demonstrated that Alcaligenes sp. GT is most closely related to the species Alcaligenes faecalis(99.6% sequence similarity to A. faecalis HR4 and 98.7% sequence similarity to A. faecalis[ATCC 8750T = DSM 30030T]. On the basis of DNA-DNA relatedness (56% similarity), the unique polyamine pattern, the physiological and biochemical differences strain GT could be distinguished from the species A. faecalis. Therefore, a new subspecies for the species Alcaligenes faecalis is proposed;Alcaligenes faecalis subsp.parafaecalis subsp. nov.

Analysis of the entire set of low molecular weight compounds (LMC), the metabolome, could provide deeper insights into mechanisms of disease and novel markers for diagnosis. In the investigation, we developed an extraction and derivatization protocol, using experimental design theory (design of experiment), for analyzing the human blood plasma metabolome by GC/MS. The protocol was optimized by evaluating the data for more than 500 resolved peaks using multivariate statistical tools including principal component analysis and partial leastsquares projections to latent structures (PLS). The performance of five organic solvents (methanol, ethanol, acetonitrile, acetone, chloroform), singly and in combination, was investigated to optimize the LMC extraction. PLS analysis demonstrated that methanol extraction was particularly efficient and highly reproducible. The extraction and derivatization conditions were also optimized. Quantitative data for 32 endogenous compounds showed good precision and linearity. In addition, the determined amounts of eight selected compounds agreed well with analyses by independent methods in accredited laboratories, and most of the compounds could be detected at absolute levels of ∼0.1 pmol injected, corresponding to plasma concentrations between 0.1 and 1 µM. The results suggest that the method could be usefully integrated into metabolomic studies for various purposes, e.g., for identifying biological markers related to diseases.

This paper reports on the high sensitivity of sub-spherical In 2 O 3-Pt nanoparticles (NPs) for detecting ppb levels of acetone, a biomarker for diabetes. The In 2 O 3-Pt NPs, in the form of monodisperse metal-oxide In 2 O 3 NPs with diameters of 6–8 nm, decorated with 2 wt% Pt metal NPs (2–3 nm) on the surface, were synthesized by a novel non-aqueous sol–gel route. NPs samples were investigated by X-ray powder diffraction (XRPD), using the advanced whole powder pattern modeling (WPPM) method, and high-resolution transmission electron microscopy (HR-TEM). The advantage of this preparative process is that it preserves metallic platinum NPs formed during the synthesis. The highly sensitive acetone sensor based on these NPs, showed a lower detection limit as low as 10 ppb or less, which is the lowest detection limit ever reported for any chemoresistive acetone sensors. This exceptional performance is likely due to the key role played by very small Pt metal NPs uniformly distributed in the In 2 O 3-Pt nanostructure. The developed sensor would be suitable for use as a highly sensitive, practical breath acetone checker for daily diet and diabetes management and diagnosis.

The objective of this study was to subject mannitol, either as a sole carbon source or in combination with glucose, and aqueous extracts of the kelp Saccharina spp., containing mannitol and laminarin, to acetone-butanol fermentation by Clostridium acetobutylicum (ATCC 824). Both mannitol and glucose were readily fermented. Mixed substrate fermentations with glucose and mannitol resulted in diauxic growth of C. acetobutylicum with glucose depletion preceding mannitol utilization. Fermentation of kelp extract exhibited triauxic growth, with an order of utilization of free glucose, mannitol, and bound glucose, presumably laminarin. The lag in laminarin utilization reflected the need for enzymatic hydrolysis of this polysaccharide into fermentable sugars. The butanol and total solvent yields were 0.12 g/g and 0.16 g/g, respectively, indicating that significant improvements are still needed to make industrial-scale acetone-butanol fermentations of seaweed economically feasible.

The aim of the present study was to propose a simple and efficient method for the isolation of high-value pigment, astaxanthin, from a low-value raw material, shrimp waste. Hexane was used as extraction solvent. The concentration obtained was 43.44 µg/g. Mobile phase for TLC was acetone: hexane in the ratio 3:7 (v/v). The sample was collected from the processing plants, Cochin, Kerala, India. The shrimp waste was transported to the laboratory in a sterile container filled with ice. The organism was identified with the styles marketed under the trade name "red ring". The wastes generated from the shrimp are cephalothorax, abdominal shell and tail portion. Adhering meat from the cephalothorax was removed and the waste was washed under running water and dried under shade. They were packed in polyethylene bags and stored at -20°C until use. A second set of sample was stored wet, after removing the adhering meat, was packed in polythene covers and stored at -20°C.

In the present work, a packed bed absorption column is designed to remove certain amounts of acetone contained in a gaseous stream. Four packing types (50-mm metal Hiflow® rings, 50-mm ceramic Pall® rings, 50-mm metal Top Pak® rings rings) are and 25-mm metal VSP® considered in order to select the most appropriate one in terms of column dimensions, pressure drop and mass-transfer results. Several design parameters were determined including column diameter (D), packing height (Z), overall mass-transfer coefficient (Km) and gas pressure drop (delta P/Z), as well as the overall number of gas-phase transfer units (NtOG), overall height of a gas-phase transfer unit (HtOG) and the effective surface area of packing (ah). The most adequate packing to use for this absorption system constitutes the 25-mm metal VSP® rings, since it provided the greatest values of Km , ah , as well as the lowest values of both Z and HtOG , meaning that it will supply the higher mass-transfer conditions with the lowest column dimensions, but it does not comply with the requirement of pressure drop delta P/Z() for this reason the next adequate packing to use for this absorption system is 50-mm ceramic Pall® rings. The influence of both gas mixture (QG) and solvent (mL') feed flowrates on D, Z, Km, P/Z, NtOG and HtOG was also evaluated for the four packing considered. The design methodology was solved using computing software MATHCAD PRIME 3.0.

The researcher’s study was all about the use of pounded cigarette butts in acetone solution to increase the resistivity of steel against rust. The purpose of the study was to properly utilize cigarette butts, which were deemed to be useless, in giving solution to the rampant steel corrosions in Brgy. 31-D, Davao City. The independent variables of the study are the melted cigarette butts in acetone solution and stainless steel used, while the dependent variable is the steel’s resistivity against rust.  The Fortune cigarette butt gained the lowest average corroded area, followed by More cigarette butt, which was lesser compared to the controlled group test, signifying that it is indeed effective. As temperature increases, the effectiveness of the independent variable decreases. Thus, the presence of nicotine from cigarette butts, specifically from Fortune and More cigarette butts, served as an oxidation film which lessened area of corrosion.

Background: Ointments (e.g., petrolatum) are thought to be occlusive, thereby blocking transcutaneous water loss and trapping water under the skin's surface. If this premise is correct, then petrolatum should delay barrier recovery after barrier perturbation, as shown previously in occluded murine skin. Objective: We reexamined the assumption that Vaseline Petroleum Jelly (VPJ) is occlusive, ascertaining both its site and mechanism of action. Methods: Barrier recovery was measured in VPJ-treated versus untreated sites after acetone-induced barrier disruption in human volunteers. Moreover, VPJ was localized within the str~tum corneum (SC) with tracers and ruthenium tetroxide staining, which allowed visualization of the depth of VPJ penetration and its relation to intercellular membrane structures. Results: VPJ accelerated, rather than impeded, barrier recovery. Moreover, VPJ was present within the interstices at all levels of the SC, where it replaced intercellular bilayers. Conclusion: VPJ neither forms nor acts like an epicutaneous impermeable membrane; instead, it permeates throughout the SC interstices, allowing normal barrier recovery despite its occlusive properties.

Successful implementation of ultrasound irradiation for the rapid synthesis of a novel series of 3-[1-(4-substituted-5-(aryldiazenyl)thiazol-2-yl)hydrazono)ethyl]-2Hchromen-2-ones 5a-h, via reactions of 2-(1-(2-oxo-2H-chromen-3-yl)ethylidene) thiosemicarbazide (2) and the hydrazonoyl halides 3(4), was demonstrated. Also, a new series of 5-arylidene-2-(2-(1-(2-oxo-2H-chromen-3-yl)ethylidene)hydrazinyl)thiazol-4(5H)-ones 10a-d were synthesized from reaction of 2 with chloroacetic acid and different aldehydes. Moreover, reaction of 2-cyano-N'-(1-(2-oxo-2H-chromen-3-yl)ethylidene)acetohydrazide (12) with substituted benzaldehydes gave the respective arylidene derivatives 13a-c under the conditions employed. The structures of the synthesized compounds were assigned based on elemental analyses and spectral data. Also, the cytototoxic activities of the thiazole derivative 5a was evaluated against HaCaT cells (human keratinocytes). It was found that compound 5a possess potent cytotoxic activity.

Validation experiments were conducted of a simple, fast, and inexpensive method for the determination of 229 pesticides fortified at 10-100 ng/g in lettuce and orange matrixes. The method is known as the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method for pesticide residues in foods. The procedure involved the extraction of a 15 g sample with 15 mL acetonitrile, followed by a liquid-liquid partitioning step performed by adding 6 g anhydrous MgSO 4 plus 1.5 g NaCl. After centrifugation, the extract was decanted into a tube containing 300 mg primary secondary amine (PSA) sorbent plus 1.8 g anhydrous MgSO 4 , which constituted a cleanup procedure called dispersive solid-phase extraction (dispersive SPE). After a second shaking and centrifugation step, the acetonitrile extract was transferred to autosampler vials for concurrent analysis by gas chromatography/mass spectrometry with an ion trap instrument and liquid chromatography/tandem mass spectrometry with a triple quadrupole instrument using electrospray ionization. Each analytical method was designed to analyze 144 pesticides, with 59 targeted by both instruments. Recoveries for all but 11 of the analytes in at least one of the matrixes were between 70-120% (90-110% for 206 pesticides), and repeatabilities typically <10% were achieved for a wide range of fortified pesticides, including methamidophos, spinosad, imidacloprid, and imazalil. Dispersive SPE with PSA retained carboxylic acids (e.g., daminozide), and <50% recoveries were obtained for asulam, pyridate, dicofol, thiram, and chlorothalonil. Many actual samples and proficiency test samples were analyzed by the method, and the results compared favorably with those from traditional methods. Mention of brand or firm name does not constitute an endorsement by the U.S. Department of Agriculture above others of a similar nature not mentioned.

The identification of hypothermia as the cause of death has always been somewhat problematic in forensic pathology because of unspecific, inconstant, or even negative macroscopic and microscopic findings. Though the simultaneous presence of frost erythema, Wischnewski spots, hemorrhages into the synovial membrane, bloody discoloration of synovial fluid of the knee, and basal vacuolization of the renal tubular epithelial cells has been indicated as strongly supportive of fatal hypothermia, their absence does not allow the diagnosis of hypothermia to be ruled out. Postmortem biochemical investigations are valuable in detecting adaptation responses to cold stress and metabolic changes that occur following cold exposure. However, ethanol intoxication prevents appearance of adaptation responses to cold, rendering the diagnosis less obvious. Immunohistochemistry, postmortem imaging, and molecular pathology have shown promising results, although at present, they do not provide pathognomonic signs of fatal hypothermia. The aim of this article is to present a review of the literature covering the significance of different postmortem investigations that are associated with hypothermia fatalities.

Acetone in the human breath is an important marker for noninvasive diagnosis of diabetes. Here, novel chemoresistive detectors have been developed that allow rapid measurement of ultralow acetone concentrations (down to 20 ppb) with high signal-to-noise ratio in ideal (dry air) and realistic (up to 90% RH) conditions. The detector films consist of (highly sensitive) pure and Si-doped WO 3 nanoparticles (10-13 nm in diameter) made in the gas phase and directly deposited onto interdigitated electrodes. Their sensing properties (selectivity, limit of detection, response, and recovery times) have been investigated as a function of operating temperature (325-500°C), relative humidity (RH), and interfering analyte (ethanol or water vapor) concentration. It was found that Si-doping increases and stabilizes the acetone-selective ε-WO 3 phase while increasing its thermal stability and, thus, results in superior sensing performance with an optimum at about 10 mol % Si content. Furthermore, increasing the operation temperature decreased the detector response to water vapor, and above 400°C, it was (e0.7) always below the threshold (10.6) for fake diabetes detection in ideal conditions. At this temperature and at 90% RH, healthy humans (e900 ppb acetone) and diabetes patients (g1800 ppb) can be clearly distinguished by a remarkable gap (40%) in sensor response. As a result, these solid state detectors may offer a portable and costeffective alternative to more bulky systems for noninvasive diabetes detection by human breath analysis.

The composition of pitch deposits occurring in pulp sheets and mill circuits during soda/anthraquinone pulping and elemental chlorine-free pulp bleaching of bast fibers of industrial hemp (Cannabis sativa) was studied. Pitch deposits were extracted with acetone, and the extracts analyzed by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Acetone extracts (15-25% of pitch deposits) were constituted by the defoamers used at the mill and by lipophilic extractives from hemp fibers. Acetone-insoluble residues (75-85% of pitch deposits) were analyzed by pyrolysis-GC/MS in the presence and absence of tetramethylammonium hydroxide. These residues were constituted by salts of fatty acids (arising from hemp fibers) with calcium, magnesium, aluminum and other cations that were identified in the deposits. It was concluded that inappropriate use of defoamer together with the presence of multivalent ions seemed to be among the causes of hemp extractives deposition in the pitch problems reported here.

An acetonitrile-based extraction method for the analysis of 169 pesticides in soya grain, using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in the positive and negative electrospray ionization (ESI) mode, has been optimized and validated. This method has been compared with our earlier published acetone-based extraction method, as part of a comprehensive study of both extraction methods, in combination with various gas chromatography-(tandem) mass spectrometry [GC-MS(/MS)] and LC-MS/MS techniques, using different detection modes. Linearity of calibration curves, instrument limits of detection (LODs) and matrix effects were evaluated by preparing standards in solvent and in the two soya matrix extracts from acetone and acetonitrile extractions, at seven levels, with six replicate injections per level. Limits of detection were calculated based on practically realized repeatability relative standard deviations (RSDs), rather than based on (extrapolated) signal/noise ratios. Accuracies (as % recoveries), precision (as repeatability of recovery experiments) and method limits of quantification (LOQs) were compared. The acetonitrile method consists of the extraction of a 2-g sample with 20 mL of acetonitrile (containing 1% acetic acid), followed by a partitioning step with magnesium sulphate and a subsequent buffering step with sodium acetate. After mixing an aliquot with methanol, the extract can be injected directly into the LC-MS/MS system, without any cleanup. Cleanup hardly improved selectivity and appeared to have minor changes of the matrix effect, as was earlier noticed for the acetone method. Good linearity of the calibration curves was obtained over the range from 0.1 or 0.25 to 10 ng mL −1 , with r 2 ≥ 0.99. Instrument LOD values generally varied from 0.1 to 0.25 ng mL −1 , for both methods. Matrix effects were not significant or negligible for nearly all pesticides. Recoveries were in the range 70-120%, with RSD ≤ 20%. If not, they were still mostly in the 50-70% range, with good precision (RSD ≤ 20%). The method LOQ values were most often 10 g kg −1 for almost all pesticides, with good repeatability RSDs. Apart from some minor pros and cons, both compared methods are fast, efficient and robust, with good method performances. The two methods were applied successfully in a routine analysis environment, during surveys in 2007 and 2008.

Various carotenoids were analyzed by ultrahigh-pressure liquid chromatography with tandem mass spectrometry detection (UHPLC-MS/MS). Three different techniques to ionize the carotenoids were compared: electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI) and atmospheric pressure photoionization (APPI). For all of the carotenoids tested, it was possible to obtain characteristic transitions for their unequivocal identification using each ionization technique. APCI was shown to be a more powerful technique to ionize the carotenoids than ESI or APPI. Transitions to differentiate carotenoids that coelute were determined to distinguish antheraxanthin from astaxanthin and lutein from zeaxanthin. In addition, four dopants were evaluated to improve ionization and enhance the carotenoid signal strength in APPI. These dopants were acetone, toluene, anisole, and chlorobenzene. Carotenoids improved their response in almost all cases when a dopant was used. The use of dopants allowed the enhancement of the carotenoid signals strength up to 178-fold.

China is one of the few countries, which maintained the fermentative acetone–butanol–ethanol (ABE) production for several decades. Until the end of the last century, the ABE fermentation from grain was operated in a few industrial scale plants. Due to the strong competition from the petrochemical industries, the fermentative ABE production lost its position in the 1990s, when all the solvent fermentation plants in China were closed. Under the current circumstances of concern about energy limitations and environmental pollution, new opportunities have emerged for the traditional ABE fermentation industry since it could again be potentially competitive with chemical synthesis. From 2006, several ABE fermentation plants in China have resumed production. The total solvent (acetone, butanol, and ethanol) production capacity from ten plants reached 210,000 tons, and the total solvent production is expected to be extended to 1,000,000 tons (based on the available data as of Sept. 2008). This article reviews current work in strain development, the continuous fermentation process, solvent recovery, and economic evaluation of ABE process in China. Challenges for an economically competitive ABE process in the future are also discussed.

The Hadamard transform-gas chromatography/mass spectrometry (HT-GC/MS) technique was successfully employed to detect acetone, a biomarker for diabetes mellitus (DM) prediction, in human breath. Samples of exhaled breath were collected from four DM patients (one type-I and three type-II) and eight volunteers (nondiabetic healthy subjects), respectively. The gas samples, without any pretreatment, were simultaneously injected into a GC column through a Hadamard-injector based on Hadamard codes. Under optimized conditions, when cyclic S-matrix orders of 255, 1023 and 2047 were used, the S/N ratios of the acetone signals were substantially improved by 8.0-, 16.0- and 22.6-fold, respectively; these improvements are in good agreement with theoretically calculated values. We found that the breath acetone concentration levels in the four DM patients and the eight volunteers ranged from 1 to 10 ppmv and 0.1 to 1 ppmv, respectively.

In this paper we describe how the spherical crystallization process by QESD method can be applied to a water-soluble drug, salbutamol sulfate. The type of solvent, antisolvent, and emulsi®er and the concentration of emulsi®er to be used for the production of spherical particles with a size range 80±500 mm are determined. Furthermore, the solvent/antisolvent ratio and the temperature difference between them (DT) are studied . It was observed that, in the case of salbutamol sulfate, the DT value has no in¯uence on the formation of spherical particles. A very large metastable zone of salbutamol sulfate in water could explain this phenomenon. Finally, the in¯uence of emulsi®er concentration and of maturation time on the size of spherical particles is studied. The results show that these two parameters must be ®xed to control the size of the recovered particles. ß

Two ferric-ion-based total antioxidant capacity methods: 1,10-phenanthroline (Phen) and ferric reducing antioxidant power (FRAP) were used for determination of antioxidant capacities (AC) of the acetonic and methanolic extracts of vegetable oils. The obtained mean Phen and FRAP values for acetonic extracts of olive oils, rapeseed, rice and four sunflower oils (39.3-336.5 and 39.5-339.6 mol Fe/100 g) were higher than for methanolic extracts (22.8-307.3 and 23.5-300.1 mol Fe/100 g). However, antioxidant capacities of methanolic extracts of corn oil, blended oils and two sunflower oils with garden green flowers (56.5-312.9 and 53.9-306.5 mol Fe/100 g for Phen and FRAP methods, respectively) were higher than for acetonic extracts of these oils (54.2-249.2 and 52.9-244.7 mol Fe/100 g for Phen and FRAP methods, respectively). There is a linear and significant correlation between these two analytical methods (r = 0.9989 and 0.9986 for acetonic and methanolic extracts). Also, total phenolic compounds (TPC) in the studied oils correlated with their antioxidant capacities determined by Phen and FRAP methods (r = 0.9012, 0.7818 and 0.8947, 0.7830 for acetonic and methanolic extracts, respectively). The comparable precision (R.S.D. = 0.8-4.6%, 0.9-4.9% and 0.7-4.0%, 0.6-4.0% for acetonic and methanolic extracts, respectively) and sensitivity (ε = 1.27 × 10 4 , 1.11 × 10 4 and 2.62 × 10 4 dm 3 mol −1 cm −1 ) for the proposed Phen and the modified FRAP methods, demonstrate the benefit of the Phen method in the routine analysis of antioxidant capacities of vegetable oils.

Clinical applications of nuclear magnetic resonance (NMR) imaging have demonstrated its great potential for noninvasive examinations of soft tissues. Here preliminary experiments are reported on mummified human tissue by means of NMR cross-sectional and transmission imaging. For this purpose the natural viscosity of the tissues has been lowered by rehydration with an aqueous solution of 20% acetone.

Introduction -Hyoscyamine and scopolamine, anti-cholinergic agents widely used in medicine, are typically obtained from plants grown under natural conditions. Since field cultivation entails certain difficulties (changeable weather, pests, etc.), attempts have been made to develop a plant in vitro culture system as an alternative source for the production of these compounds. During experiments to locate the limiting steps in the biotechnological procedure, it is important to monitor not only the levels of the final products but also the changes in the concentration of their precursors. Objective -To develop a HPTLC method for the separation and quantitation of the main tropane alkaloids hyoscyamine and scopolamine, their respective direct precursors littorine and anisodamine, and cuscohygrine, a product of a parallel biosynthetic pathway that shares a common precursor (N-methyl-Δ 1 -pyrrolium cation) with tropane alkaloids. Methods -Using alkaloid extracts from Atropa baetica hairy roots, different TLC chromatographic systems and developing procedures were investigated. Results -Full separation of all compounds was obtained on HPTLC Si60 F 254 plates preconditioned with mobile phase vapours (chloroform:methanol:acetone:25% ammonia ratios of 75:15:10:1.8, v/v/v/v). The chromatograms were developed twice (at distances of 4.0 and 3.0 cm) in a Camag twin trough chamber and visualised with Dragendorff's reagent. Densitometric detection (l = 190 and 520 nm) was used for quantitative analyses of the different plant samples. Conclusion -This method can be recommended for quantitation of hyoscyamine, scopolamine, anisodamine, littorine and cuscohygrine in different plant material (field grown vs. in vitro cultures).

A number of volatile organic compounds (VOCs) including acetone, methyl ethyl ketone, toluene, ethylbenzene, m,p-xylene, styrene, and o- xylene released during food decaying processes were measured from three types of decaying food samples (Kimchi (KC), fresh fish (FF), and salted fish (SF)). To begin with, all the food samples were contained in a 100-mL throwaway syringe. These samples were then analyzed sequentially for up to a 14-day period. The patterns of VOC release contrasted sharply between two types of fish (FF and SF) and KC samples. A comparison of data in terms of total VOC showed that the mean values for the two fish types were in the similar magnitude with 280 ± 579 (FF) and 504 ± 1,089 ppmC (SF), while that for KC was much lower with 16.4 ± 7.6 ppmC. There were strong variations in VOC emission patterns during the food decaying processes between fishes and KC that are characterized most sensitively by such component as styrene. The overall results of this study indicate that concentration levels of the VOCs differed significantly between the food types and with the extent of decaying levels through time.

This paper compares the extraction effectiveness of six different commonly applied extraction techniques for the determination of PCBs in soil. The techniques included are Soxhlet, Soxtec, ultrasonication extraction, supercritical fluid extraction, microwave-assisted extraction and accelerated solvent extraction. For none of the techniques were the extraction conditions optimized, but instead the extraction parameters were based on the experience from previous successful investigation published by a number of research groups worldwide. In general, all extraction techniques were capable of producing accurate data for one native PCB contaminated soil diluted with another soil sample to obtain two concentration levels. It could therefore be concluded that any of the investigated techniques can be used with success if the extraction conditions applied are chosen wisely.

The aim of this paper was the analysis of five androstane isomers by thin-layer chromatography (TLC). The choice of proper mobile phase and the optimization of the mobile phase composition are very important because the chromatographic separation is difficult to achieve. In the first step, the proper mobile phase system was chosen from seven elution systems presented in the literature using numerical taxonomy method. The proper solvent system was found to be the mixture of chloroform, acetone, and petroleum ether. In the second step the composition of mobile phase was optimized by "simplex" method and "prisma" method. The optimum TLC system can be applied for the separation of androstane isomers from real samples such as drug formulation, biological and natural sources.

A simple pre-column derivatization procedure for HPLC analysis of cholesterol in biological samples was developed. Cholesterol was treated with chromic acid and sulfuric acid in acetone (the Jones oxidation) and cholest-4-en-3,6-dione was formed. The reaction was finished in 5 min at room temperature and the product showed a strong UV absorbance at 250 nm that enabled an HPLC detection limit of 0.2 pmol. With stigmasterol as an internal standard, the reaction was applied to the analysis of total and free cholesterol in serum and high-density lipoproteins and the analysis showed a within-run and total coefficient of variation of about 0.2% and 0.5%, respectively.

Manufacturing butanol, ethanol, and acetone through grain fermentation has been attracting increasing research interest. In the production of these chemicals from fermentation, the cost of product recovery constitutes the major portion of the total production cost. Developing cost-effective flowsheets for the downstream processing is, therefore, crucial to enhancing the economic viability of this manufacturing method. The present work is concerned with the synthesis of such a process that minimizes the cost of the downstream processing. At the outset, a wide variety of processing equipment and unit operations, i.e., operating units, is selected for possible inclusion in the process. Subsequently, the exactly defined superstructure with minimal complexity, termed maximal structure, is constructed from these operating units with the rigorous and highly efficient graph-theoretic method for process synthesis based on process graphs (P-graphs). Finally, the optimal and near-optimal flowsheets in terms of cost are identified.

This study evaluated the in¯uence of chemical surface treatments in the repair strength of a heat-cured acrylic resin (Lucitone 550, (LU)). A total of 70 specimens were made with LU according to American Dental Association (ADA) speci®cation No. 12. Of these, 14 remained intact and were used as a control group (GI). A total of 56 specimens were selected randomly. These specimens were cut in the middle (10 mm), repaired with a microwave acrylic resin (Acron MC (AC)), and processed in a microwave oven for 3 min at 500 W. Prior to the repair, the surface of the cut ends received different chemical treatments (GIII = AC monomer dipping/30 s; GIV = acetone dipping/30 s; GV = acetone dipping/ 15 s + blast of air + AC monomer dipping/15 s; GVI = no wetting treatment). However, 14 intact specimens made with AC formed a second control group (GII). The effect of the chemical treatments on the surface texture of LU was observed with scanning electron microscopy. Flexural test results were submitted to paired t-test and showed statistical differences (P < 0á05) only between the pairs GIV± GV and GIV±GVI. Strength mean values of repaired specimens were statistically lower (79±90%) than GII mean values. Strength mean values of GVI and GIV were 93 and 106%, respectively, of GI mean, showing no statistical differences. Scanning electron microscopic observations revealed various effects of the chemical treatments on the denture base resin surface. In conclusion, the wetting surface treatments affected the bond strength between the two acrylic resins, and no statistical differences in strength were observed between intact heat-cured denture base material and the same material repaired with microwave acrylic resin.

A one-step microwave-assisted extraction (MAE) procedure was developed for the simultaneous extraction of organophosphorus pesticide and fungicide residues in soil which have been greatly used in agriculture. Parameters that could influence the MAE efficiency such as irradiation power, temperature, time and solvent were investigated, and extraction efficiencies in the range of 92.6-103.7% were obtained using 400 W (100% output) at 160 °C for 10 min with only 12 mL of acetone-hexane (2:1, v/v). The analytes in extracts were analyzed directly by gas chromatography-mass spectrometry (GC-MS) without any further cleanup. At 5 and 50 ng g(-1) fortification levels for each analyte, the average recoveries obtained were ranged from 70.0% to 120.0% with relative standard deviation (RSD) between 0.2% and 14%. The method was linear over 1-250 ng g(-1) with a correlation coefficient (r(2)) between 0.9916 and 0.9966. The detection limits (S/N=3) were between 0.10 and 0.12 ng g(-1). The applicability of the method was demonstrated by analyzing field soil samples collected from six intensive horticultural sites in Ethiopia.