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D Values (d + value)
Selected AbstractsOne class classifiers for process monitoring illustrated by the application to online HPLC of a continuous processJOURNAL OF CHEMOMETRICS, Issue 3-4 2010Sila Kittiwachana Abstract In process monitoring, a representative out-of-control class of samples cannot be generated. Here, it is assumed that it is possible to obtain a representative subset of samples from a single ,in-control class' and one class classifiers namely Q and D statistics (respectively the residual distance to the disjoint PC model and the Mahalanobis distance to the centre of the QDA model in the projected PC space), as well as support vector domain description (SVDD) are applied to disjoint PC models of the normal operating conditions (NOC) region, to categorise whether the process is in-control or out-of-control. To define the NOC region, the cumulative relative standard deviation (CRSD) and a test of multivariate normality are described and used as joint criteria. These calculations were based on the application of window principal components analysis (WPCA) which can be used to define a NOC region. The D and Q statistics and SVDD models were calculated for the NOC region and percentage predictive ability (%PA), percentage model stability (%MS) and percentage correctly classified (%CC) obtained to determine the quality of models from 100 training/test set splits. Q, D and SVDD control charts were obtained, and 90% confidence limits set up based on multivariate normality (D and Q) or SVDD D value (which does not require assumptions of normality). We introduce a method for finding an optimal radial basis function for the SVDD model and two new indices of percentage classification index (%CI) and percentage predictive index (%PI) for non-NOC samples are also defined. The methods in this paper are exemplified by a continuous process studied over 105.11,h using online HPLC. Copyright © 2010 John Wiley & Sons, Ltd. [source] Reduction of Microflora of Whole Pickling Cucumbers by BlanchingJOURNAL OF FOOD SCIENCE, Issue 8 2000F. Breidt ABSTRACT: There is increasing interest in developing methods to control the presence of pathogenic and spoilage microorganisms on fresh fruits and vegetables. Blanching whole pickling cucumbers for 15 s at 80 °C reduced microbial cell counts by 2 to 3 log cycles from an initial population of typically 106 CFU/g. Vegetative microorganisms survived this blanching process (10,fold greater in number than the spore count), presumably because they were located beneath the surface of the cucumber. The sensitivity to heat of selected populations was measured by determining D values for pooled microorganisms (termed D values) isolated from fresh cucumbers. The Enterobacteriaceae population and the total aerobic microflora had similar Dp values to each other and to the D value for a selected lactic acid bacterium. [source] Hydrogen-isotopic compositions in Allan Hills 84001 and the evolution of the martian atmosphereMETEORITICS & PLANETARY SCIENCE, Issue 2 2000N. Sugiura The deviation seems to be caused by addition of varying amounts of terrestrial water in the case of carbonate. In the case of maskelynite, H is heterogeneously distributed and the deviation in ,D values seems to be due to mixing of this indigenous heavy H with isotopically normal H present in the SIMS chamber. The indigenous ,D value in ALH 84001 seems to be ,2000%,. Carbonate rather than maskelynite seems to be the main carrier of H in ALH 84001. Because ALH 84001 is ,4 Ga old, the H-isotopic composition suggests that a large fraction of the initial martian atmosphere had already escaped by 4 Ga. [source] Hydrogen and oxygen isotopes of water from inclusions in minerals: design of a new crushing system and on-line continuous-flow isotope ratio mass spectrometric analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2009Yuri V. Dublyansky An analytical line for stable isotope analyses of water recovered from fluid inclusions in minerals was built and successfully tested. The line is based on the principle of continuous-flow analysis of water via high-temperature reduction on glassy carbon. It includes a custom-designed set of high-efficiency crushers and a cryo-focusing cell. This paper provides details of the line design and discusses strategies for line conditioning and mitigation of memory effects. The line allows measurements of hydrogen and oxygen isotopes during a single acquisition. The precision of the analyses depends on the amount of water released from the inclusions. The best results are obtained for samples containing at least 0.1,0.2,µL (0.06,0.11,µmol) H2O. For such samples precision is better than 1.5, for ,D and 0.5, for ,18O (1,). Smaller amounts of water can be measured but at lower precision. Analyses of modern calcite formed under stable conditions in a deep cave allowed assessment of the accuracy of the analyses. The ,D values measured in fluid inclusions of this working standard match the ,D value of the parent water, and the oxygen isotope values agree within ca. 0.5,. This indicates that fluid inclusions trapped in calcite at near-ambient temperatures (e.g. speleothems and low-temperatures phreatic calcite) faithfully preserve the original isotopic composition of the parent waters. Copyright © 2009 John Wiley & Sons, Ltd. [source] A method for quantitative determination of deuterium content in biological materialRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 6 2005Yihui He A method was developed for quantitative determination of deuterium incorporated into live organisms or biological macromolecules. The deuterated biological material was mixed with a bovine serum albumin (BSA) supporter to make a homogeneous sample for which the ,D value (vs. VSMOW) was analyzed using a dual-inlet gas isotope mass spectrometer. The method is described in detail, and the equation for calculation of deuterium content is presented, i.e., C,=,1/500,×,k,×,RVSMOW,×,C,×,106 ppm. Deuterated hepatitis A virus (HAV) RNA and BSA were systematically investigated. The results demonstrate that the method is capable of direct measurement of deuterium content, and is highly repeatable and reliable with a standard deviation of ±3,. It is stressed that the quantity of deuterated sample required is extremely small as a result of using BSA as supporter. The method may be applied in many fields, and has the strengths of simplicity, relative cheapness, and robustness. Copyright © 2005 John Wiley & Sons, Ltd. [source] Tectonic Controls on the Formation of the Liwu Cu-rich Sulfide Deposit in the Jianglang Dome, S W ChinaRESOURCE GEOLOGY, Issue 2 2003Dan-Ping Yan Abstract. The Liwu Cu-rich sulfide deposit occurs within the Jianglang dome in the eastern margin of the Tibetan plateau. The dome consists of a core, a middle slab and a cover sequence. The main deposit is hosted in the core with minor ore bodies in the middle slab. The protolith of the core consists of clastic sedimentary rocks with inter-layered volcanic rocks. All of the ore bodies are substantially controlled by an extensional detachment fault system. The ore bodies within the core are distributed along the S2 foliation in the hinge of recumbent fold (D2), whereas ore bodies with en echelon arrangement are controlled by the mylonitic foliation of the lower detachment fault. Ore bodies within the middle slab are oriented with their axes parallel to the mylonitic foliation. Pyrite and pyrrhotite from the ores contain Co ranging from 37 to 1985 ppm, Ni from 2.5 to 28.1 ppm, and Co/Ni ratios from 5 to 71. These sulfides have ,34S values ranging from 1.5 to 7.5 % whereas quartz separates have ,18O values of 11.9 and 14.3 % and inclusion fluid in quartz has ,D value of-88.1 %. These features suggest that the deposit was of hydrothermal origin. Two ore-forming stages are recognized in the evolution of the Jianglang dome. (1) A low-temperature ore-forming process, during the tectonic transport of the upper plate above the lower detachment, and the initial phase of the footwall updom-ing at 192,177 Ma. (2) A medium-temperature ore-forming stage, related to the final structural development of the initial detachment at 131,81Ma. Within the core, the ore bodies of the first stage were uplifted to, or near, the brittle/ductile horizon where the ore-forming metals were re-concentrated and enriched. A denudation stage in which a compressional tectonic event produced eastward thrusting overprinted the previous structures, and finally denuded the deposit. The Liwu Cu-rich sulfide deposit was formed during a regional extensional tectonic event and is defined as a tectono-strata-bound hydrothermal ore deposit. [source] CO2 Density-Raman Shift Relation Derived from Synthetic Inclusions in Fused Silica Capillaries and Its ApplicationACTA GEOLOGICA SINICA (ENGLISH EDITION), Issue 5 2009Yucai SONG Abstract: The densities of CO2 inclusions in minerals are commonly used to determine the crystallizing conditions of the host minerals. However, conventional microthermometry is difficult to apply for inclusions of small size (< 5,10 ,m) or low density. Raman analysis is an alternative method for determining CO2 density, provided that the CO2 density,Raman shift relation is known. This study aims to establish this CO2 density,Raman shift relation by using CO2 inclusions synthesized in fused silica capillaries. By using this newly-developed synthetic technique, we formed pure CO2 inclusions, and their densities were determined by microthermometry. The Raman analysis showed that the relation between CO2 density (D in g/cm3) and the separations (? in cm,1) between the two main bands (i.e. Fermi diad bands) in CO2 Raman spectra can be represented by a cubic equation: D (g/cm3)=0.74203(,0.019?3+5.90332?2,610.79472?+21050.30165),3.54278 (r2=0.99920). Our calculated D value for a given ? is between those obtained from two previously-reported equations, which were derived from different experimental methods. An example was given in this study to demonstrate that the densities of natural CO2 inclusions that could not be derived from microthermometry could be determined by using our method. [source] Migratory connectivity in a declining bird species: using feather isotopes to inform demographic modellingDIVERSITY AND DISTRIBUTIONS, Issue 4 2010Thomas S. Reichlin Abstract Aim, Conservation programmes for endangered migratory species or populations require locating and evaluating breeding, stopover and wintering areas. We used multiple stable isotopes in two endangered European populations of wrynecks, Jynx torquilla L., to locate wintering regions and assess the degree of migratory connectivity between breeding and wintering populations. Location, Switzerland and Germany. Methods, We analysed stable nitrogen (,15N), carbon (,13C) and hydrogen (,D) isotopes from wing feathers from two populations of wrynecks to infer their wintering origins and to assess the strength of migratory connectivity. We tested whether variation in feather isotopic values within the Swiss population was affected by bird age and collection year and then considered differences in isotopic values between the two breeding populations. We used isotopic values of summer- and winter-grown feathers to estimate seasonal distributions. Finally, we calculated a species-specific ,D discrimination factor between feathers and mean annual ,D values to assign winter-grown feathers to origin. Results, Bird age and collection year caused substantial isotopic variation in winter-grown feathers, which may be because of annually variable weather conditions, movements of birds among wintering sites and/or reflect asynchronous moulting or selection pressure. The large isotopic variance in winter-grown feathers nevertheless suggested low migratory connectivity for each breeding population, with partially overlapping wintering regions for the two populations. Main conclusions, Isotopic variance in winter-grown feathers of two breeding populations of wrynecks and their geographical assignment point to defined, albeit overlapping, wintering areas, suggesting both leapfrog migration and low migratory connectivity. On this basis, integrative demographic models can be built looking at seasonal survival patterns with links to local environmental conditions on both breeding and wintering grounds, which may elucidate causes of declines in migratory bird species. [source] Contrasting paleofluid systems in the continental basement: a fluid inclusion and stable isotope study of hydrothermal vein mineralization, Schwarzwald district, GermanyGEOFLUIDS (ELECTRONIC), Issue 2 2007B. BAATARTSOGT Abstract An integrated fluid inclusion and stable isotope study was carried out on hydrothermal veins (Sb-bearing quartz veins, metal-bearing fluorite,barite,quartz veins) from the Schwarzwald district, Germany. A total number of 106 Variscan (quartz veins related to Variscan orogenic processes) and post-Variscan deposits were studied by microthermometry, Raman spectroscopy, and stable isotope analysis. The fluid inclusions in Variscan quartz veins are of the H2O,NaCl,(KCl) type, have low salinities (0,10 wt.% eqv. NaCl) and high Th values (150,350°C). Oxygen isotope data for quartz range from +2.8, to +12.2, and calculated ,18OH2O values of the fluid are between ,12.5, and +4.4,. The ,D values of water extracted from fluid inclusions vary between ,49, and +4,. The geological framework, fluid inclusion and stable isotope characteristics of the Variscan veins suggest an origin from regional metamorphic devolatilization processes. By contrast, the fluid inclusions in post-Variscan fluorite, calcite, barite, quartz, and sphalerite belong to the H2O,NaCl,CaCl2 type, have high salinities (22,25 wt.% eqv. NaCl) and lower Th values of 90,200°C. A low-salinity fluid (0,15 wt.% eqv. NaCl) was observed in late-stage fluorite, calcite, and quartz, which was trapped at similar temperatures. The ,18O values of quartz range between +11.1, and +20.9,, which translates into calculated ,18OH2O values between ,11.0, and +4.4,. This range is consistent with ,18OH2O values of fluid inclusion water extracted from fluorite (,11.6, to +1.1,). The ,D values of directly measured fluid inclusion water range between ,29, and ,1,, ,26, and ,15,, and ,63, and +9, for fluorite, quartz, and calcite, respectively. Calculations using the fluid inclusion and isotope data point to formation of the fluorite,barite,quartz veins under near-hydrostatic conditions. The ,18OH2O and ,D data, particularly the observed wide range in ,D, indicate that the mineralization formed through large-scale mixing of a basement-derived saline NaCl,CaCl2 brine with meteoric water. Our comprehensive study provides evidence for two fundamentally different fluid systems in the crystalline basement. The Variscan fluid regime is dominated by fluids generated through metamorphic devolatilization and fluid expulsion driven by compressional nappe tectonics. The onset of post-Variscan extensional tectonics resulted in replacement of the orogenic fluid regime by fluids which have distinct compositional characteristics and are related to a change in the principal fluid sources and the general fluid flow patterns. This younger system shows remarkably persistent geochemical and isotopic features over a prolonged period of more than 100 Ma. [source] Heterogeneity in Serum 25-Hydroxy-Vitamin D Response to Cholecalciferol in Elderly Women with Secondary Hyperparathyroidism and Vitamin D DeficiencyJOURNAL OF AMERICAN GERIATRICS SOCIETY, Issue 8 2010Andrea Giusti MD OBJECTIVES: To compare the effects on parathyroid hormone (PTH) and 25-hydroxy-vitamin D (25(OH)D) of two dosing regimens of cholecalciferol in women with secondary hyperparathyroidism (sHPTH) and hypovitaminosis D and to investigate variables affecting 25(OH)D response to cholecalciferol. DESIGN: Randomized-controlled trial with 6-month follow-up. SETTING: Two osteoporosis centers in northern Italy. PARTICIPANTS: Sixty community-dwelling women aged 65 and older with sHPTH and hypovitaminosis D, creatinine clearance greater than 65 mL/min and without diseases or drugs known to influence bone and vitamin D metabolism. INTERVENTION: Cholecalciferol 300,000 IU every 3 months, once at baseline and once at 3 months (intermittent D3 group) or cholecalciferol 1,000 IU/day (daily D3 group). MEASUREMENTS: Serum PTH, 25(OH)D, calcium, bone-specific alkaline phosphatase, ,-C-terminal telopeptide of type I collagen, phosphate, 24-hour urinary calcium excretion. RESULTS: The two groups had similar baseline characteristics. All participants had vitamin D deficiency [25(OH)D<20 ng/mL)], and 36 subjects (60%) had severe deficiency (<10 ng/mL), with no difference between the groups (severe deficiency: intermittent D3 group, n=18; daily D3 group, n=18). After 3 and 6 months, both groups had a significant increase in 25(OH)D and a reduction in PTH. Mean absolute increase±standard deviation of 25(OH)D at 6 months was higher in the intermittent D3 group (22.7±11.8 ng/mL) than in the daily D3 group (13.7±6.7 ng/mL, P<.001), with a higher proportion of participants in the intermittent D3 group reaching desirable serum concentration of 25(OH)D , 30 ng/mL (55% in the intermittent D3 group vs 20% in the daily D3 group, P<.001). Mean percentage decrease of PTH in the two groups was comparable, and at 6 months, a similar proportion of participants reached normal PTH values. 25(OH)D response to cholecalciferol showed a wide variability. In a logistic regression analysis, body mass index and type of treatment appeared to be significantly associated with normalization of 25(OH)D values. CONCLUSION: Cholecalciferol 300,000 IU every 3 months was more effective than 1,000 IU daily in correcting vitamin D deficiency, although the two groups achieved similar effects on PTH at 6 months. Only 55% of the higher-dose intermittent group reached desirable concentrations of 25(OH)D, suggesting that yet-higher doses will be required for adequate vitamin D repletion. [source] Growth and survival of non-O157:H7 Shiga-toxin-producing Escherichia coli in cow manureJOURNAL OF APPLIED MICROBIOLOGY, Issue 1 2007B. Fremaux Abstract Aims:, The main objective of this study was to evaluate the behaviour of non-O157:H7 Shiga-toxin-producing Escherichia coli (STEC) strains in cow manure. Methods and Results:, A mixture of eight green-fluorescent-protein-labelled STEC strains was inoculated around 106,107 CFU g,1 into four manure heaps. Two heaps were regularly turned and the two others remained unturned. STEC counts and physical parameters (temperature, pH, moisture content and oxido-reduction potential) were monitored for 1000 manure samples. The highest mean pH values were obtained near the surface at the base of all manure heaps. At the surface, the moisture content decreased from 76·5% to 42% in turned heaps. Temperatures reached 65°C near the main body of all manure heaps, and only 35°C near the superficial parts located at the base of them. These two sites (the centre and the base) were associated with D values for the STEC counts of 0·48 and 2·39 days, respectively. We were able to detect STEC strains during 42 days in turned manure heaps and during at least 90 days in unturned ones. Conclusions:, These results emphasize the long-term survival of non-O157:H7 STEC in cow manure. Significance and Impact of the Study:, Good management practices (e.g. turning) should be respected in order to minimize the risk of environmental contamination by STEC. [source] INACTIVATION OF STAPHYLOCOCCUS AUREUS EXPOSED TO DENSE-PHASE CARBON DIOXIDE IN A BATCH SYSTEMJOURNAL OF FOOD PROCESS ENGINEERING, Issue 1 2009HUACHUN HUANG ABSTRACT The inactivation of Staphylococcus aureus exposed to dense-phase carbon dioxide (DPCD) was investigated, and the kinetics of come-up time (CUT) in pressurization was monitored with come-down time (CDT) and temperature fluctuation in depressurization. CUT was about 2.5, 3.5, 4.0 and 4.0 min; CDT was 3.4, 3.7, 4.5 and 4.5 min; lowest temperature of samples in depressurization was 4, ,1, ,15 and ,22C, corresponding to 10, 20, 30 and 40 MPa at 37C. The inactivation behavior of S. aureus was closely related to the variables of process pressure, holding-pressure time (HPT), process temperature and process cycling. The log reduction of S. aureus at 40 MPa for 30-min HPT was significantly greater (P < 0.05), but the inactivation effect at 10, 20 and 30 MPa was similar. The log reduction of S. aureus at 30 and 40 MPa for 60-min HPT was similar and significantly greater (P < 0.05), while the inactivation effect at 10 and 20 MPa was similar. The inactivation of S. aureus against HPT conformed to a fast,slow biphase kinetics; the two stages were well fitted to a first-order model with higher regression coefficients R2 = 1.000 and 0.9238; their respective D values (decimal reduction time) were 16.52 and 70.42 min. As the process temperature increased, the log reduction of S. aureus increased significantly (P < 0.05); the inactivation kinetics of S. aureus versus process temperature was characterized with a fast inactivation rate from 32 to 45C and a slow inactivation rate from 45 to 55C. As compared to one-process cycling for a total of 60-min HPT, four-process cycling resulted in a significant reduction of S. aureus, and its maximal reduction was near to 5 log cycles, indicating that more process cycling caused more inactivation of S. aureus under identical pressure and temperature with equal HPT. However, the maximal reduction was 0.09 and 0.12 log cycles for two- and four-process cyclings with 0-min HPT, indicating that pressurization and depressurization had a lesser effect on the inactivation of S. aureus, while HPT was significant in DPCD to inactivate S. aureus. PRACTICAL APPLICATIONS Dense-phase carbon dioxide (DPCD) is a novel technology to achieve cold pasteurization and/or sterilization of liquid and solid materials, and is likely to replace or partially substitute currently and widely applied thermal processes. This study showed that DPCD effectively inactivated Staphylococcus aureus inoculated in 7.5% sodium chloride broth, and the inactivation behavior of S. aureus was closely related to the pressure, holding-pressure time, temperature and process cycling. Based on this observation, the technology of DPCD can be applied in the pasteurization of foods such as milk and various fruit juices, especially thermal-sensitive materials. [source] THERMAL DEATH TIMES OF ESCHERICHIA COLI IN YOUNG COCONUT ENDOSPERM BEVERAGEJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2009ALONZO A. GABRIEL ABSTRACT The decimal reduction times (D values) of Escherichia coli (American Type Culture Collection 25922) were established in a young coconut endosperm beverage, a famous local drink in the Philippines and in many tropical countries. Artificially inoculated cells were heated to 60, 70 and 80C at various heating times prior to survivor enumeration by surface plating onto pre-solidified Eosine Methylene Blue Agar. Results showed that the surviving populations significantly (P < 0.05) decreased with increasing exposure time and temperature. The calculated D values ranged from 0.26 ± 0.01 to 0.56 ± 0.08 min. Validation of the results by establishing the thermal resistance of other E. coli isolates in the coconut beverage medium was recommended. PRACTICAL APPLICATION The study established the thermal inactivation rates of Escherichia coli (American Type Culture Collection 25922) in a young coconut endosperm beverage medium in various heating temperatures. The results obtained from this study may be used in the calculations of appropriate thermal process schedules for the test beverage against the test organism. [source] EFFECT OF HIGH HYDROSTATIC PRESSURE ON SPORES OF GEOBACILLUS STEAROTHERMOPHILUS SUSPENDED IN SOYMILKJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 5 2007YOKIUSHIRDHILGILMARA ESTRADA-GIRÓN ABSTRACT The inactivation of Geobacillus stearothermophilus spores (ATCC 7953) inoculated in soymilk was investigated using high hydrostatic pressure (550, 585 and 620 MPa) in combination with temperature (70, 80 and 90C) for selected times (2 s to 15 min). Inactivation of spores occurred at all selected treatments. Less than 10 CFU/mL of G. stearothermophilus were observed after 7 min of treatment at 620 MPa and 90C. An increase in the inactivation rate constant, at the highest pressure, was observed, resulting in a decrease in D values at all temperatures. D values were calculated as 10.6, 6.2 and 3.5 min for 70, 80 and 90C, respectively after pressurization at 620 MPa. zp values decreased as temperature increased with values ranging from 142 to 238 MPa. The activation energy required for inactivation of G. stearothermophilus spores in soymilk, at the selected treatments, was in the range of 37.9,57.4 kJ/mol. [source] THERMAL INACTIVATION KINETICS OF ALKALINE PHOSPHATASE IN BUFFER AND MILKJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2006S. FADILO ABSTRACT A detailed kinetic study on the thermal inactivation of alkaline phosphatase (ALP) added into buffer and pasteurized milk and for ALP naturally present in raw cow's milk has been performed. Kinetic parameters (rate constant, k; decimal reduction time, D; activation energy, Ea; and z value) were evaluated based on the first-order rate model at 50,80C. The temperature sensitivity of the kinetic parameters was evaluated considering the Arrhenius-type Ea model. All kinetic behaviors were well described by the first-order model (r2 > 0.91). The D values increased with increasing temperature. Higher temperatures resulted in higher rates of enzyme inactivation as indicated by lower D values and higher k values. There are significant differences (P < 0.01) among the D values for ALP in buffer and milk at treated temperatures. The rate of enzyme inactivation was much more rapid in buffer than in pasteurized milk. The evaluated Ea values for ALP added into the buffer and pasteurized milk, and for ALP naturally present in raw milk were 97.2, 149.9 and 207.8 kJ/mol, respectively. The inactivation kinetics of ALP during heat treatment was found to be dependent on the composition of the medium, and the time and temperature of the heat treatment. [source] Reduction of Microflora of Whole Pickling Cucumbers by BlanchingJOURNAL OF FOOD SCIENCE, Issue 8 2000F. Breidt ABSTRACT: There is increasing interest in developing methods to control the presence of pathogenic and spoilage microorganisms on fresh fruits and vegetables. Blanching whole pickling cucumbers for 15 s at 80 °C reduced microbial cell counts by 2 to 3 log cycles from an initial population of typically 106 CFU/g. Vegetative microorganisms survived this blanching process (10,fold greater in number than the spore count), presumably because they were located beneath the surface of the cucumber. The sensitivity to heat of selected populations was measured by determining D values for pooled microorganisms (termed D values) isolated from fresh cucumbers. The Enterobacteriaceae population and the total aerobic microflora had similar Dp values to each other and to the D value for a selected lactic acid bacterium. [source] Thermal Inactivation Kinetics of Salmonella and Listeria in Ground Chicken Breast Meat and Liquid MediumJOURNAL OF FOOD SCIENCE, Issue 4 2000R.Y. Murphy ABSTRACT: Thermal inactivation of Listeria innocua and 6 Salmonella serotypes in ground chicken breast meat was compared to that in peptone (0.1%) - agar (0.1%) solution. Inoculated samples were packed in a thin-wall metal tube and submerged in a water bath at temperatures ranging from 55.0 to 70.0 °C. For Salmonella and Listeria, the D values in ground chicken breast meat at 55 to 70 °C were higher (p < 0.0001) than those in peptone-agar solution; however, the z values were not significantly different. Complete first-order inactivation models, with Arrhenius temperature dependency, were developed for each inoculum and medium. [source] Timing and nature of fluid flow and alteration during Mesoproterozoic shear zone formation, Olary Domain, South AustraliaJOURNAL OF METAMORPHIC GEOLOGY, Issue 3 2005C. CLARK Abstract The development of shear zones at mid-crustal levels in the Proterozoic Willyama Supergroup was synchronous with widespread fluid flow resulting in albitization and calcsilicate alteration. Monazite dating of shear zone fabrics reveal that they formed at 1582 ± 22 Ma, at the end of the Olarian D3 deformational event and immediately prior to the emplacement of regional S-type granites. Two stages of fluid flow are identified in the area: first an albitizing event which involved the addition of Na and loss of Si, K and Fe; and a second phase of calcsilicate alteration with additions of Ca, Fe, Mg and Si and removal of Na. Fluid fluxes calculated for albitization and calcsilicate alteration were 5.56 × 109 to 1.02 × 1010 mol m,2 and 2.57 × 108,5.20 × 109 mol m,2 respectively. These fluxes are consistent with estimates for fluid flow through mid-crustal shear zones in other terranes. The fluids associated with shearing and alteration are calculated to have ,18O and ,D values ranging between +8 and +11,, and ,33 and ,42,, respectively, and ,Nd values between ,2.24 and ,8.11. Our results indicate that fluids were derived from metamorphic dehydration of the Willyama Supergroup metasediments. Fluid generation occurred during prograde metamorphism of deeper crustal rocks at or near peak pressure conditions. Shear zones acted as conduits for major crustal fluid flow to shallow levels where peak metamorphic conditions had been attained earlier leading to the apparent ,retrograde' fluid-flow event. Thus, the peak metamorphism conditions at upper and lower crustal levels were achieved at differing times, prior to regional granite formation, during the same orogenic cycle leading to the formation of retrograde mineral assemblages during shearing. [source] Role of fluids in the metamorphism of the Alpine Fault Zone, New ZealandJOURNAL OF METAMORPHIC GEOLOGY, Issue 1 2001J. K. Vry Abstract Models of fluid/rock interaction in and adjacent to the Alpine Fault in the Hokitika area, South Island, New Zealand, were investigated using hydrogen and other stable isotope studies, together with field and petrographic observations. All analysed samples from the study area have similar whole-rock ,D values (,DWR = ,56 to ,30,, average = ,45,, n = 20), irrespective of rock type, degree of chloritization, location along the fault, or across-strike distance from the fault in the garnet zone. The green, chlorite-rich fault rocks, which probably formed from Australian Plate precursors, record nearly isothermal fluid/rock interaction with a schist-derived metamorphic fluid at high temperatures near 450,500°C (,D of water in equilibrium with the green fault rocks (,DH2O, green) ,,,18,; ,D of water in equilibrium with the greyschists and greyschist-derived mylonites (,DH2O, grey) , ,19, at 500°C; ,DH2O, green , ,17,; ,DH2O, grey , ,14, at 450°C). There is no indication of an influx of a meteoric or mantle-derived fluid in the Alpine Fault Zone in the study area. The Alpine Fault Zone at the surface shows little evidence of late-stage retrogression or veining, which might be attributed to down-temperature fluid flow. It is probable that prograde metamorphism in the root zone of the Southern Alps releases metamorphic fluids that at some region rise vertically rather than following the trace of the Alpine Fault up to the surface, owing to the combined effects of the fault, the disturbed isotherms under the Southern Alps, and the brittle,ductile transition. Such fluids could mix with meteoric fluids to deposit quartz-rich, possibly gold-bearing veins in the region c. 5,10 km back from the fault trace. These results and interpretations are consistent with interpretations of magnetotelluric data obtained in the South Island GeopHysical Transects (SIGHT) programme. [source] Thermal tolerance of acid-adapted and unadapted Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in cantaloupe juice and watermelon juiceLETTERS IN APPLIED MICROBIOLOGY, Issue 6 2005M. Sharma Abstract Aims:, A study was performed to determine D values of acid-adapted and unadapted cells of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes in cantaloupe juice and watermelon juice. Methods and Results:,Salmonella enterica serotype Poona, S. enterica serotype Saphra, two strains of E. coli O157:H7, and two strains of L. monocytogenes were grown in tryptic soy broth (TSB) and TSB supplemented with 1% glucose for 24 h at 37°C. Decimal reduction times (D values) of cells suspended in unpasteurized cantaloupe juice and watermelon juice were determined. Acid-adapted cells of Salmonella and E. coli O157:H7, but not L. monocytogenes, had increased thermal tolerance compared with cells that were not acid-adapted. There was no correlation between soluble solids content of the two types of juice and thermal resistance. Conclusions:, Growth of Salmonella and E. coli O157:H7 in cantaloupe juice, watermelon juice, or other acidic milieu, either in preharvest or postharvest environments, may result in cross protection to heat. The pasteurization conditions necessary to achieve elimination of pathogens from these juices would consequently have to be more severe if cells are habituated to acidic environments. Significance and Impact of the Study:, Insights from this study provide guidance to developing pasteurization processes to eliminate Salmonella, E. coli O157:H7, and L. monocytogenes in cantaloupe juice and watermelon juice. [source] Hydrogen-isotopic compositions in Allan Hills 84001 and the evolution of the martian atmosphereMETEORITICS & PLANETARY SCIENCE, Issue 2 2000N. Sugiura The deviation seems to be caused by addition of varying amounts of terrestrial water in the case of carbonate. In the case of maskelynite, H is heterogeneously distributed and the deviation in ,D values seems to be due to mixing of this indigenous heavy H with isotopically normal H present in the SIMS chamber. The indigenous ,D value in ALH 84001 seems to be ,2000%,. Carbonate rather than maskelynite seems to be the main carrier of H in ALH 84001. Because ALH 84001 is ,4 Ga old, the H-isotopic composition suggests that a large fraction of the initial martian atmosphere had already escaped by 4 Ga. [source] Effect of electron beam treatments on degradation kinetics of polylactic acid (PLA) plastic waste under backyard composting conditionsPACKAGING TECHNOLOGY AND SCIENCE, Issue 2 2009L. Fernando Vargas Abstract The effects of electron beam irradiation on backyard composting behaviour of polylactic acid (PLA) polymer were evaluated. Samples (10,mm2 × 0.75,mm) from thermoformed PLA drinking cups were exposed to 10,MeV electron beam irradiation at doses of 0, 72, 144 and 216,kGy. Irradiated PLA samples were placed in heat-sealed, plastic screen and added to organic feedstock in a rotating composter within a computer-controlled environmental chamber for 10 weeks at 35°C. Changes in weight, structural integrity and molecular weight were assessed over time. Results show that irradiation enhanced PLA breakdown. PLA weight decreased by increasing amounts as irradiation dose increased. Sample brittleness increased with irradiation dose and composting time. Finally, PLA molecular weight decreased as irradiation dose and compost time increased. Molecular weight D values for irradiated PLA were found to be about 430,kGy. After 1 week in a typical backyard composter, molecular weight D values increased to about 560,kGy and then fell to about 380,kGy after 2 weeks of composting. Samples irradiated at 216,kGy showed a reduction in weight of 9.4% after 10 weeks of composting, and a reduction of weight-average molecular weight of 93.7% after 6 weeks. Copyright © 2008 John Wiley & Sons, Ltd. [source] Hydrogen and oxygen isotopes of water from inclusions in minerals: design of a new crushing system and on-line continuous-flow isotope ratio mass spectrometric analysisRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 17 2009Yuri V. Dublyansky An analytical line for stable isotope analyses of water recovered from fluid inclusions in minerals was built and successfully tested. The line is based on the principle of continuous-flow analysis of water via high-temperature reduction on glassy carbon. It includes a custom-designed set of high-efficiency crushers and a cryo-focusing cell. This paper provides details of the line design and discusses strategies for line conditioning and mitigation of memory effects. The line allows measurements of hydrogen and oxygen isotopes during a single acquisition. The precision of the analyses depends on the amount of water released from the inclusions. The best results are obtained for samples containing at least 0.1,0.2,µL (0.06,0.11,µmol) H2O. For such samples precision is better than 1.5, for ,D and 0.5, for ,18O (1,). Smaller amounts of water can be measured but at lower precision. Analyses of modern calcite formed under stable conditions in a deep cave allowed assessment of the accuracy of the analyses. The ,D values measured in fluid inclusions of this working standard match the ,D value of the parent water, and the oxygen isotope values agree within ca. 0.5,. This indicates that fluid inclusions trapped in calcite at near-ambient temperatures (e.g. speleothems and low-temperatures phreatic calcite) faithfully preserve the original isotopic composition of the parent waters. Copyright © 2009 John Wiley & Sons, Ltd. [source] Gas chromatography flow rates for determining deuterium/hydrogen ratios of natural gas by gas chromatography/high-temperature conversion/isotope ratio mass spectrometryRAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 16 2008Wanglu Jia The effects of the gas chromatography flow rate on the determination of the deuterium/hydrogen (D/H) ratios of natural gas utilising gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/TC/IRMS) have been evaluated. In general, the measured ,D values of methane, ethane and propane decrease with increase in column flow rate. When the column flow rate is 1,mL/min or higher, which is commonly used for the determination of D/H ratios of natural gas, the organic H in gas compounds may not be completely converted into hydrogen gas. Based on the results of experiments conducted on a GC column with an i.d. of 0.32,mm, a GC flow rate of 0.6,mL/min is proposed for determining the D/H ratios of natural gas by GC/TC/IRMS. Although this value may be dependent on the instrument conditions used in this work, we believe that correct ,D values of organic compounds with a few carbon atoms are obtained only when relatively low GC flow rates are used for D/H analysis by GC/TC/IRMS. Moreover, as the presence of trace water could significantly affect the determination of D/H ratios, a newly designed inlet liner was used to remove trace water contained in some gas samples. Copyright © 2008 John Wiley & Sons, Ltd. [source] Dashuigou Tellurium Deposit in Sichuan Province, China: S, C, O, and H Isotope Data and Their Implications on Hydrothermal MineralizationRESOURCE GEOLOGY, Issue 1 2002Jingwen MAO Abstract: Dashuigou, a unique tellurium-dominated deposit over the world, is located in the western margin of the Yangtze cra-ton in southwestern China. It is characterized by high-grade tellurium accompanied by bismuth, gold, silver, and sulfur, and occurs in the area of less than one km2. The mineralization is divided into three stages, i.e. (1) tellurium-bearing pyrrhotite,pyrite stage, (2) tetradymite stage, and (3) auriferous quartz veins stage. Tellurium mineralization coexisting with bismuth, silver, selenium, and gold predominantly develops in the stage 2, while the stage 1 is enriched only in sulfur and iron, and the stage 3 is very weakly mineralized with gold. The ,34S values of sulfides in the ore of the deposit vary in a narrow range of ,3.1 - +2.8 per mil with ,3.1 - +2.8 per mil for the stage 1 and ,0.5 - +2.1 for the stage 2, showing the isotopic characteristics of mantle derived sulfur. The ,13C values of vein dolomites vary from ,5.3 to ,7.2 per mil, with ,5.3 - ,6.6 per mil for the stage 1 and ,5.3 - ,7.2 per mil for the stage 2, which are significantly different from those of surrounding Triassic marble with ,13C values of ,0.3 - +2.8 per mil, and show characteristics of mantle derived carbon. The ,18O values of vein dolomites range from +10.2 to +13.1 per mil, which are higher than those of carbonatite, but lower than those of the marble. Their corresponding ,18Owater values are +0.6 - +3.9 per mil, with +2.7 - +3.8 per mil for the stage 1 and +0.6 - +3.9 per mil for the stage 2. The data implies that these vein carbonates were formed by the mixing fluids of magmatic or mantle source with meteoric or formation water. The ,18O values of ore-forming fluids responsible for the formation of vein quartz are estimated to be +3.2 to +6.8, the ,D values of inclusion fluids of the quartz are measured to be ,54 to ,82 per mil. All those stable isotopic data suggest the involvement of the fluids from mantle and/or mantle-derived magmas through fault system in the forming process of the Dashuigou tellurium deposit. [source] Muscle fractal vascular branching pattern and microvascular perfusion heterogeneity in endurance-trained and untrained menTHE JOURNAL OF PHYSIOLOGY, Issue 2 2003Kari K. Kalliokoski Less heterogeneous skeletal muscle perfusion has recently been reported in endurance-trained compared to untrained men at macrovascular level. The causes of this difference in perfusion heterogeneity are unknown as is whether the same difference is observed in microvasculature. We hypothesised that the difference could be caused by changes in muscle vascular branching pattern. Perfusion was measured in resting and exercising muscle in 14 endurance-trained and seven untrained men using [15O]water and positron emission tomography. Fractal dimension (D) of perfusion distribution was calculated as a measure of fractal characteristics of muscle vascular branching pattern. Perfusion heterogeneity in microvascular units (1 mm3 samples) was estimated using the measured heterogeneity in voxels of positron emission tomography (PET) images (relative dispersion, RD =s.d./mean) and corresponding D values. D was similar between the groups (exercising muscle 1.11 ± 0.07 and 1.14 ± 0.06, resting muscle 1.12 ± 0.06 and 1.14 ± 0.03, trained and untrained, respectively). Trained men had lower perfusion (151 ± 44 vs. 218 ± 87 ml min,1 kg,1, P < 0.05) and macrovascular perfusion heterogeneity (relative dispersion 21 ± 5 vs. 25 ± 5 %, P < 0.05) in exercising muscle than untrained men. Furthermore, estimated perfusion heterogeneity in microvascular units in exercising muscle was also lower in trained men (33 ± 7 vs.48 ± 19 %, P < 0.05). These results show that fractal vascular branching pattern is similar in endurance-trained and untrained men but perfusion is less heterogeneous at both the macro- and the microvascular level in endurance-trained men. Thus, changes in fractal branching pattern do not explain the differences in perfusion heterogeneity between endurance-trained and untrained men. [source] Basin evolution, diagenesis and uranium mineralization in the Paleoproterozic Thelon Basin, Nunavut, CanadaBASIN RESEARCH, Issue 3 2010Eric E. Hiatt ABSTRACT The Paleoproterozoic (Statherian) Thelon Basin is located in the Churchill Province of the Canadian Shield, formed following the Trans-Hudson Orogeny. Basin formation followed an interval of felsic volcanism and weathering of underlying bedrock. The diagenetic evolution of the Thelon lasted about one billion years and was punctuated by fluid movement influenced by tectonic events. Early quartz cements formed in well-sorted, quartz-rich facies during diagenetic stage 1; fluids in which these overgrowths formed had ,18O values near 0, (Vienna Standard Mean Ocean Water). Uranium-rich apatite cement (P1) also formed during diagenetic stage 1 indicating that oxygenated, uranium-bearing pore water was present in the basin early in its diagenetic history. Syntaxial quartz cement (Q1) formed in water with ,18O from ,4 to ,0.8, in diagenetic stage 2. Diagenetic stage 3 occurred when the Thelon Formation was at ca. 5 km depth, and was marked by extensive illitization, alteration of detrital grains, and uranium mineralization. Basin-wide, illite crystallized at ,200 °C by fluids with ,18O values of 5,9, and ,D values of ,60 to ,31,, consistent with evolved basinal brines. Tectonism caused by the accretion of Nena at ca. 1600 Ma may have provided the mechanism for brine movement during deep burial. Diagenetic stage 4 is associated with fracturing and emplacement of mafic dikes at ca. 1300 Ma, quartz cement (Q3) in fractures and vugs, further illitization, and recrystallization of uraninite (U2). Q3 cements have fluid inclusions that suggest variable salinities, ,18O values of 1.5,9,, and ,D values of ,97 to ,83, for stage 4 brines. K-feldspar and Mg-chlorite formed during diagenetic stage 5 at ca. 1000 Ma in upper stratigraphic sequences, and in the west. These phases precipitated from low-temperature, isotopically distinct fluids. Their distribution indicates that the basin hydrostratigraphy remained partitioned for >600 Ma. [source] Migration, Diet, or Molt?BIOTROPICA, Issue 4 2010Interpreting Stable-Hydrogen Isotope Values in Neotropical Bats ABSTRACT Migratory behavior in bats is poorly described, particularly in the Neotropics. Stable-hydrogen isotope (,D) analysis may allow tracking of altitudinal movements of bats but has not been explored. ,D values in rainwater (,Dp) deplete linearly with altitude and are reflected in the keratinous tissues of animals through diet. A mismatch between keratin ,D (,Dk) and that expected at the capture site based on ,Dp can indicate prior migration. We collected rainwater, claws and hair from eight bat species at two lower-montane forest sites in Nicaragua. Claw ,D for Carollia brevicauda and hair and claws for Desmodus rotundus (known to be non-migratory) fell within the predicted range based on rainwater (,17 to ,60,) suggesting these tissues were synthesized at the study site. ,D tissue values for Artibeus toltecus, Sturnira lilium, Glossophaga soricina, Anoura geoffroyi, and hair for C. brevicauda were more negative than predicted for the capture site (,60,) suggesting tissue synthesis at higher elevation and migration downslope to the capture site. However, our study area represents the highest elevation in the region; the nearest appropriate higher elevations are 350,500 km away and seasonal migration is expected to be<200 km. Thus we consider that seasonal shifts in ,Dp (9 to ,45,) may result in differences in species which molt at different times, and that diet may have driven differences in ,D. Our results suggest that the effects of molt timing and diet may first need to be understood before ,D may be successfully used to track bat movements. [source] Ab initio prediction of optical rotation: Comparison of density functional theory and Hartree-Fock methods for three 2,7,8-trioxabicyclo[3.2.1]octanesCHIRALITY, Issue 4 2002P.J. Stephens Abstract We report ab initio calculations of the frequency-dependent electric dipole-magnetic dipole polarizabilities, ,(,), at the sodium D line frequency and, thence, of the specific rotations, [,]D, of 2,7,8-trioxabicyclo[3.2.1]octane, 1, and its 1-methyl derivative, 2, using the Density Functional Theory (DFT) and Hartree-Fock/Self-Consistent Field (HF/SCF) methodologies. Gauge-invariant (including) atomic orbitals (GIAOs) are used to ensure origin-independent [,]D values. Using large basis sets which include diffuse functions DFT [,]D values are in good agreement with experimental values (175.8° and 139.2° for (1S,5R)- 1 and - 2, respectively); errors are in the range 25,35°. HF/SCF [,]D values, in contrast, are much less accurate; errors are in the range 75,95°. The use of small basis sets which do not include diffuse functions substantially lowers the accuracy of predicted [,]D values, as does the use of the static limit approximation: ,(,) , ,(o). The use of magnetic-field-independent atomic orbitals, FIAOs, instead of GIAOs, leads to origin-dependent, and therefore nonphysical, [,]D values. We also report DFT calculations of [,]D for the 1-phenyl derivative of 1, 3. DFT calculations find two stable conformations, differing in the orientation of the phenyl group, of very similar energy, and separated by low barriers. Values of [,]D predicted using two different algorithms for averaging over phenyl group orientations are in good agreement with experiment. In principle, the absolute configuration (AC) of a chiral molecule can be assigned by comparison of the optical rotation predicted ab initio to the experimental value. Our results demonstrate the critical importance of the choice of ab initio methodology in obtaining reliable optical rotations and, hence, ACs, and show that, at the present time, DFT constitutes the method of choice. Chirality 14:288,296, 2002. © 2002 Wiley-Liss, Inc. [source] Effect of leading edge cut on the aerodynamics of ram-air parachutesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 1 2005R. Balaji Abstract The effect of the configuration of leading edge cut on the aerodynamic performance of ram-air parachutes is studied via two-dimensional flow simulations. The incompressible Reynolds-averaged Navier,Stokes equations, in primitive variables, are solved using a stabilized finite-element formulation. The Baldwin,Lomax model is employed for turbulence closure. Flow past an LS(1) 0417 airfoil is investigated for various configurations of the leading edge cut and results are compared with those from a Clark-Y airfoil section. It is found that the configuration of the leading edge cut affects the lift-to-drag ratio (L/D) of the parachute very significantly. The L/D value has strong implications on the flight performance of the parachute. One particular configuration results in a L/D value that is in excess of 25 at 7.5° angle of attack. Results are presented for other angles of attack for this configuration. Copyright © 2004 John Wiley & Sons, Ltd. [source] | |||||||||||||||||||||||||