Short Extractions Research Articles

Contrasting effects of rice husk pyrolysis temperature on silicon dissolution and retention of cadmium (Cd) and dimethylarsinic acid (DMA)

Arsenic (As) and cadmium (Cd) are two toxins that affect rice, and their ability to do so may be lessened by soil incorporation of rice husk residues. Rice husks are typically removed from fields and used as a fuel source at rice mills but contain silicon (Si) and other nutrients. It has previously been shown that soil incorporation of rice husk or charred husk can release Si to soil solution to decrease As uptake and promote As methylation, and studies suggest char can additionally decrease Cd availability through several potential mechanisms including adsorption, precipitation, liming, and growth dilution. Charring conditions will impact husk Si dissolution rate and potential to immobilize Cd and possibly methylated As. Here, we compared uncharred husk to husk biochars pyrolyzed at 450, 600, 750, and 900 °C for differences in Si dissolution rate and adsorption of Cd and dimethylarsinic acid (DMA)—the dominant methylated As species present in paddy soils and grain. We hypothesized that Si dissolution rate and Cd adsorption would decrease, and DMA adsorption would increase with pyrolysis temperature. Si release decreased with pyrolysis temperature in the general order: uncharred husk > 450 °C > 600 °C = 750 °C = 950 °C but those differences were not due to SiO2 crystallization with increasing temperature. Additionally, short (< 5 d) lab-based extractions underestimate Si release from uncharred husk while overestimating release from biochars. Controlling for pH changes/liming effect, adsorption isotherms showed very weak DMA adsorption, while Cd adsorption was favored on higher temperature (950 °C) biochar and was not predicted well by cation exchange capacity (CEC). When applied in a soil incubation study using non-contaminated soil, the biochar had no impact on Cd porewater concentrations while low temperature (450 °C) rice husk biochar led to the highest Si:As ratio. Biochar did not strongly influence Cd and DMA solubility at 1% w/w amendment.

The approach to sample acquisition and its impact on the derived human fecal microbiome and VOC metabolome.

Recent studies have illustrated the importance of the microbiota in maintaining a healthy state, as well as promoting disease states. The intestinal microbiota exerts its effects primarily through its metabolites, and metabolomics investigations have begun to evaluate the diagnostic and health implications of volatile organic compounds (VOCs) isolated from human feces, enabled by specialized sampling methods such as headspace solid-phase microextraction (hSPME). The approach to stool sample collection is an important consideration that could potentially introduce bias and affect the outcome of a fecal metagenomic and metabolomic investigation. To address this concern, a comparison of endoscopically collected (in vivo) and home collected (ex vivo) fecal samples was performed, revealing slight variability in the derived microbiomes. In contrast, the VOC metabolomes differ widely between the home collected and endoscopy collected samples. Additionally, as the VOC extraction profile is hyperbolic, with short extraction durations more vulnerable to variation than extractions continued to equilibrium, a second goal of our investigation was to ascertain if hSPME-based fecal metabolomics studies might be biased by the extraction duration employed. As anticipated, prolonged extraction (18 hours) results in the identification of considerably more metabolites than short (20 minute) extractions. A comparison of the metabolomes reveals several analytes deemed unique to a cohort with the 20 minute extraction, but found common to both cohorts when the VOC extraction was performed for 18 hours. Moreover, numerous analytes perceived to have significant fold change with a 20 minute extraction were found insignificant in fold change with the prolonged extraction, underscoring the potential for bias associated with a 20 minute hSPME.

Validation of a liquid chromatography-tandem mass spectrometry screening method to monitor 58 antibiotics in milk: a qualitative approach

A multi-residue method was developed for monitoring antibiotic residues in milk using liquid chromatography coupled to a tandem quadrupole mass spectrometer (LC/MS-MS). Two very short extractions followed by two LC/MS-MS acquisitions allowed the screening of 58 antibiotics belonging to eight different families (penicillins, cephalosporins, sulfonamides, macrolides, lincosamides, aminoglycosides, tetracyclines, and quinolones). This method is currently implemented in the laboratory in a qualitative way, i.e. monitoring the presence or absence of residue in a sample and identification of the analyte before the confirmation step. In order to assess the performance of this method, a validation strategy described in an internal guideline for the validation of screening methods was applied. The aim of the validation was to prove sufficient sensitivity of the method to detect all the targeted antibiotics at the level of interest (maximum residue limit, MRL) at least. According to European Commission Decision 2002/657/EC, the suitable sensitivity of a screening method can be demonstrated when the CCβ is below or equal to the MRL and so the false-compliant rate below or equal to 5% at the MRL level. The validation scheme was established in order to take into account various variability factors: the apparatus response, the interday repeatability, the matrix effect, etc. The results of the validation clearly demonstrate the suitability of this method for the detection and identification of more than 50 antibiotics and they are in agreement with the results obtained in routine analysis.

In vivo Skin Irritation Potential of a Castanea sativa (Chestnut) Leaf Extract, a Putative Natural Antioxidant for Topical Application

Topical application of natural antioxidants has proven to be effective in protecting the skin against ultraviolet-mediated oxidative damage and provides a straightforward way to strengthen the endogenous protection system. However, natural products can provoke skin adverse effects, such as allergic and irritant contact dermatitis. Skin irritation potential of Castanea sativa leaf ethanol:water (7:3) extract was investigated by performing an in vivo patch test in 20 volunteers. Before performing the irritation test, the selection of the solvent and extraction method was guided by the 1,1-diphenyl-2-picryl hydrazyl (DPPH) free radical scavenging test and polyphenols extraction (measured by the Folin Ciocalteu assay). Iron-chelating activity and the phenolic composition (high performance liquid chromatography/diode array detection) were evaluated for the extract obtained under optimized conditions. The extraction method adopted consisted in 5 short extractions (10 min.) with ethanol:water (7:3), performed at 40 degrees. The IC(50) found for the iron chelation and DPPH scavenging assays were 132.94 +/- 9.72 and 12.58 +/- 0.54 microg/ml (mean +/- S.E.M.), respectively. The total phenolic content was found to be 283.8 +/- 8.74 mg GAE/g extract (mean +/- S.E.M.). Five phenolic compounds were identified in the extract, namely, chlorogenic acid, ellagic acid, rutin, isoquercitrin and hyperoside. The patch test carried out showed that, with respect to irritant effects, this extract can be regarded as safe for topical application.

Chemical-Sensory Characterization of Dairy Manure Odor Using Headspace Solid-Phase Microextraction and Multidimensional Gas Chromatography Mass Spectrometry-Olfactometry

Livestock operations are associated with emissions of odor, gases, and particulate matter. The majority of previous livestock odor studies focused on swine operations whereas relatively few relate to dairy cattle. Identifying the compounds responsible for the primary odor impact is a demanding analytical challenge because many critical odor components are frequently present at very low concentrations within a complex matrix of numerous insignificant volatiles. The objective of this study was to describe a chemical-sensory profile of dairy manure odor using headspace solid-phase microextraction (HS-SPME) and multidimensional gas chromatography-mass spectrometry-olfactometry (MDGC-MS-O). Two analytical approaches were used: (1) HS-SPME time-series extractions (from seconds up to 20 hr) followed by gas chromatography-mass spectrometry-olfactometry (GC-MS-O) analyses, and (2) relatively short HS-SPME extractions (30 min) followed by MDGC-MS-O analyses on selected chromatogram heart-cuts. Dairy manure was collected at research dairy farms in the United States and Israel. Volatile organic compounds (VOCs) resolved from multiple analyses included sulfur-containing compounds, volatile fatty acids, ketones, esters, and phenol/indole derivatives. A total of 86 potential odorants were identified. Of them, 17 compounds were detected by the human nose only. A greater number of VOCs and odorous compounds were detected, as well as higher mass loading, on solid-phase microextraction (SPME) fibers observed for longer extractions with SPME. However, besides sulfur-containing compounds, other selected compounds showed no apparent competition and displacement on the SPME fiber. The use of MDGC-MS-O increased chromatographic resolution even at relatively short extractions and revealed 22 additional odorants in one of the regions of the chromatogram. The two analytical approaches were found to be parallel to some extent whereas MDGC-MS-O can also be considered as a complementary approach by resolving more detailed chemical-sensory odor profiles.

Mammalian SEPT2 Is Required for Scaffolding Nonmuscle Myosin II and Its Kinases

Mammalian septin SEPT2 belongs to a conserved family of filamentous GTPases that are associated with actin stress fibers in interphase cells and the contractile ring in dividing cells. Although SEPT2 is essential for cytokinesis, its role in this process remains undefined. Here, we report that SEPT2 directly binds nonmuscle myosin II (myosin II), and this association is important for fully activating myosin II in interphase and dividing cells. Inhibition of the SEPT2-myosin II interaction in interphase cells results in loss of stress fibers, while in dividing cells this causes instability of the ingressed cleavage furrow and dissociation of the myosin II from the Rho-activated myosin kinases ROCK and citron kinase. We propose that SEPT2-containing filaments provide a molecular platform for myosin II and its kinases to ensure the full activation of myosin II that is necessary for the final stages of cytokinesis.

R5 An audit of local compliance with general anaesthetic guidelines outlined for paediatric dentistry

Objectives: To assess current practice in terms of diagnosis, treatment planning and consent in the use of dental general anaesthetic (GA). To compare current practice to national guidelines and implement any changes required to improve clinical practice.Methods: A retrospective study was carried out over 1 year (2004–2005). 100 paediatric patients undergoing long (comprehensive care) and short (extractions only) dental GA were randomly selected. A proforma was designed to collect data, from patient records, regarding presenting complaint, medical history, treatment carried out during and before GA and consent. Patients who attended oral and maxillofacial clinics were not included.Results: In most cases, GA was justified inline with guidelines but consent and treatment planning could be improved.Conclusion: The department is adhering to guidelines in prescribing GA for patients. It is hoped that by producing a departmental policy, this could improve.

Measurements of glucose on the skin surface, in stratum corneum and in transcutaneous extracts: implications for physiological sampling.

Obtaining representative physiological samples for glucose analysis remains a challenge especially when developing less invasive glucose monitoring systems for diabetic patients. In the present study the glucose content of the stratum corneum was compared with the amount of glucose obtained by short aqueous extractions from a site on the dorsal wrist, using high pressure liquid chromatography with pulsed amperometric detection. Ten successive aqueous 1-minute extractions of the site yielded a total of 60 ng cm(-2). The total glucose content of the stratum corneum of the site, determined from 30 successive tape-strippings of the site, was 360 ng cm(-2). After tape-stripping, the transcutaneous aqueous extraction rate was 86 +/- 13 ng cm(-2) min(-1), compared with rates of 80-600 ng cm(-2) min(-1) obtained with suction effusion or microdialysis after tape-stripping. Glucose on the surface of the skin and within the stratum corneum should be considered as sources of extraneous glucose contamination during testing of less invasive glucose monitoring devices.

SPME applied to the study of volatile organic compounds emitted by three species of Eucalyptus in situ. Solid-phase micro extraction.

Headspace solid-phase microextraction coupled to gas chromatography/ion trap mass spectrometry-65 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) was used to identify and monitor the emission patterns of biogenic volatile organic compounds from leaves of Eucalyptus dunnii, Eucalyptus saligna, and Eucalyptus citriodora in situ. Short extractions (1 min) were performed every 30 min for periods of 8-10 h during 24 days taking advantage of the high capacity of this porous polymer coating. Forty-two compounds were detected and 20 identified in the headspace of E. saligna leaves, and 19 of 27 compounds were identified in the headspace of E. dunnii leaves. The emission pattern of (E)-beta-ocimene and rose oxide suggests that they may play a bioactive role in Eucalyptus.

Selective extraction of oxygenates from savory and peppermint using subcritical water

The yields of oxygenated and non-oxygenated flavour and fragrance compounds from savory (Satureja hortensis) and peppermint (Mentha piperita) were compared using subcritical water extraction, supercritical carbon dioxide extraction (SFE) and hydrodistillation. Extraction rates with subcritical water increased with temperature (100–175 °C), but some desired organics (linalool and γ-terpinene) showed substantial degradation at temperatures >150 °C. However, subcritical water did not expose extracted compounds to atmospheric oxygen (as occurs in hydrodistillation) and thus may avoid the degradation of compounds like thymoquinone. Extraction of savory with subcritical water at 100 °C for 40 min gave ca. 100% recoveries (compared to hydrodistillation) for thymol and carvacrol, and >150% recoveries of borneol and linalool. Recoveries with 60 min of SFE (pure CO2 at 400 bar and 50 °C) were similar to hydrodistillation for borneol and linalool, but only ca. 50% for thymol and carvacrol. For peppermint, 30 min (at 150 °C) or 12 min (at 175 °C) of subcritical water extraction and 1 h of SFE gave good quantitative agreement with 4 h of hydrodistillation for carvone, pulegone, piperitone, eucalyptol, menthone, neomenthol and menthol, but the short subcritical water extractions only recovered ca. 40% of the less polar menthyl acetate. Subcritical water preferentially extracts more polar (oxygenated) flavour compounds, and ca. 80% extraction of oxygenated flavour compounds could be achieved under conditions which only extracted ca. 10–15% of the monoterpenes and <5% of the sesquiterpenes. In contrast, SFE had the lowest degree of selectivity and SFE extracts included plant alkane waxes as well as the same flavour compounds recovered by hydrodistillation. Copyright © 2001 John Wiley & Sons, Ltd.

Selective extraction of oxygenates from savory and peppermint using subcritical water

The yields of oxygenated and non-oxygenated flavour and fragrance compounds from savory (Satureja hortensis) and peppermint (Mentha piperita) were compared using subcritical water extraction, supercritical carbon dioxide extraction (SFE) and hydrodistillation. Extraction rates with subcritical water increased with temperature (100–175 °C), but some desired organics (linalool and γ-terpinene) showed substantial degradation at temperatures >150 °C. However, subcritical water did not expose extracted compounds to atmospheric oxygen (as occurs in hydrodistillation) and thus may avoid the degradation of compounds like thymoquinone. Extraction of savory with subcritical water at 100 °C for 40 min gave ca. 100% recoveries (compared to hydrodistillation) for thymol and carvacrol, and >150% recoveries of borneol and linalool. Recoveries with 60 min of SFE (pure CO2 at 400 bar and 50 °C) were similar to hydrodistillation for borneol and linalool, but only ca. 50% for thymol and carvacrol. For peppermint, 30 min (at 150 °C) or 12 min (at 175 °C) of subcritical water extraction and 1 h of SFE gave good quantitative agreement with 4 h of hydrodistillation for carvone, pulegone, piperitone, eucalyptol, menthone, neomenthol and menthol, but the short subcritical water extractions only recovered ca. 40% of the less polar menthyl acetate. Subcritical water preferentially extracts more polar (oxygenated) flavour compounds, and ca. 80% extraction of oxygenated flavour compounds could be achieved under conditions which only extracted ca. 10–15% of the monoterpenes and <5% of the sesquiterpenes. In contrast, SFE had the lowest degree of selectivity and SFE extracts included plant alkane waxes as well as the same flavour compounds recovered by hydrodistillation. Copyright © 2001 John Wiley & Sons, Ltd.

Extraction Conditions Affect Protein Recovery and Enzyme Activity in Wood Wafers Exposed to Stain Fungi and Bioprotectants

Summary We investigated the ability of selected buffers to extract proteins and other materials from the surfaces and subsurfaces of ponderosa pine wafers colonized by selected wood stain fungi and potential bioprotectant bacteria. The effects of extraction conditions on enzyme activity were also analyzed. The addition of Tween 80 to the extraction media markedly enhanced total protein recovery as well as enzyme activity. Increasing the extraction time from 6 to 12 hours failed to increase total protein recovery, indicating that either most of the protein was removed earlier or proteases in the wood had attacked proteins liberated during extraction. Relatively short extractions using sodium acetate buffer amended with Tween 80, therefore, produced the best protein recovery and enzyme activity. These conditions can be used for extracting wood colonized by various combinations of stain fungi and bacterial bioprotectants to study the effects of the interaction on physiologic activities of the target fungi.

CHARACTERIZATION OF DISSOLUTION PRODUCTS FROM TWO TURKISH LIGNITES BY1H NMR, IR AND GC TECHNIQUES

ABSTRACT Some structural features of the dissolution products from two Turkish lignites ( Beypazari and Tuncbi-lek lignites) have been investigated with proton nuclear magnetic resonance and infra-red spectroscopies and gas chromatography. The results indicate that, in general, no substantial changes occur in the structural characteristics of the soluble products obtained from different extraction conditions. This is true especially for preasphaltene and asphaltene fractions. On the other hand, some structural differences were observed in the compositions of oil fractions especially in the neutral fraction of oils from the different experimental conditions. The neutral oils from the low temperature and short time extractions are mainly consisted of alkylated aromatics and include a very small quantity of longer chain paraffins. Whereas the oils from the extractions at high temperatures and longer times include several long straight-chain paraffins (C15 - C32) with higher quantity. Hydrogen atmosphere is m...

Solvent extraction of fish offal

SummaryData are given which show the effect of the various extraction variables on the extraction of fish meal in both the laboratory and pilot plant. The use of wetting agents, although promising in the laboratory, does not appear to be of much value for pilot plant operation. A higher percentage of the oil components is removed by trichloroethylene under a given set of extracting conditions than with hexane. The mechanism of the extraction is believed to be one of surface‐washing for short extractions, and for longer extractions this washing process is supplemented by diffusion.

OBSERVATIONS ON THE CHEMICAL NATURE AND FORMATION OF AUXIN IN THE AVENA COLEOPTILE

OBSERVATIONS ON THE CHEMICAL NATURE AND FORMATION OF AUXIN IN THE AVENA COLEOPTILE