bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field Detection and Sensitive Determination of Copper in Soil and Airborne Dust Particulates with1-[Pyridyl-(2)-azo]-naphthol-(2), N-Phenyl-N′-(4-methylphenyl)benzamidine, and Triton X-100
Authors: Thakur Manisha , Deb Manas Kanti 
Published: February 2020

Abstract
A rapid field detection and spectrophotometric method for determining copper is described. The method is based on extraction of the red Cu(II)-1-[pyridyl-(2)-azo]naphthol-(2) (PAN) complex with N-Phenyl-N'-(4-methylphenyl)benzamidine (PMPBA) in the presence of a nonionic surfactant, Triton X-100 (TX-100) at pH 8.0–9.3. The molar absorptivity of the red Cu(II)-PAN–TX-100–PMPBA complex is 1.90 × 10s L/mol/cm at 550 nm, the wavelength of maximum absorption. The detection limit is 1 ng Cu/mL aqueous solution. The system obeys Beer’s law up to a concentration of 0.4 μg Cu(II)/mL or 4 μg/10 mL in organic solution. Precision was checked by finding the relative standard deviation (RSD) for N = 10 at a level of 2.0 μg/10 mL Cu(II), which was 1.5%. The validity was tested by determining total Cu in soil and airborne dust particulate samples. Six soil and 24 dust fallout samples were analyzed. Cu concentrations in soil ranged from 2.88 ± 0.05 ppm to 9.34 ± 0.16 ppm, with RSD values ranging from 1.6 to 2.1 % (N = 5). Cu concentrations in dust fallout ranged from 33 ± 01 ppb to 557 ±10 ppb with, RSD values ranging from 1.6 to 3.0%. These data agreed very closely with results of analyses by atomic absorption spectrophotometry.
Interference by Methyl Levulinate in Determination of Total Fat in Low-Fat,High-Sugar Products by Gas Chromatographic Fatty Acid Methyl Ester (GC-FAME) Analysis
Authors: Eller Fred J 
Published: February 2020

Abstract
Gas chromatographic fatty acid methyl ester (GC FAME) analyses of some acid-hydrolyzed foods revealed a large peak that did not correspond to any FAME standards. The unknown peak eluted just after the C12 FAME. If the fatty acid response factor and the conversion factor for the nearest calibrated peak (C12 FAME) were used to determine the total fat, the resulting total fat determination was much higher than expected. This peak was present only in acid-hydrolyzed samples and was absent in extracts obtained with supercritical CO2 or solvents without acid hydrolysis. The compound was isolated, analyzed by mass spectrometry and nuclear magnetic resonance spectroscopy, and proved by synthesis to be methyl-4-oxopentanoate (methyl levulinate). Its source was determined to be sugar in the product formula. Levulinic acid is produced by acid hydrolysis of sugar and is transesterified by BF3 in methanolto methyl levulinate. Although methyl levulinate may appear in the GC analyses of any acid-hydrolyzed products containing sugar, if the ratio of fat to sugar is high, the impact of methyl levulinate on fat determination would be small. Onthe other hand, the presence of methyl levulinate in analyses of low-fat, high-sugar prod ucts is potentially problematic if not recognized, al though GC analysis can account for the presence of this compound.
Rapid Determination of Lysine in Biological Samples by Isocratic Liquid Chromatography
Authors: Or-Rashid Mamun M , Onodera Ryoji , Wadud Shaila , Nasser Mohamed-Emad A , Amin Mohammad R 
Published: February 2020

Abstract
A simple, rapid, and sensitive method was developed for detection and quantitation of lysine (Lys) in various biological samples by isocratic liquid chromatography (LC). Samples containing Lys and other amino acids were derivatized with 9-fluorenylmethyl chloroformate (FMOC-CI). The mobile phase used for isocratic elution was 50 mmol/L sodium acetate buffer (pH 4.20)-acetonitrile (43 + 57, v/v). Lys was detected with a UV detector at 265 nm. The derivatized Lys eluted from a LiChrospher 100 RP-18 (150× 4.0 mm id) column at a retention time of 5.6 min. The limit of detection was 0.73 μmol/L (signal-to-noise [S/N] ratio, 3:1), and the limit of quantitation was 2.37 μmol/L (S/N ratio, 10:1). Lys recoveries from fortified biological samples were &gt;97.5%. Average Lys contents found in rumen fluid samples collected before the morning feeding and at 2.0,4.0, and 6.0 h after feeding were 4.26,3.34,3.58, and 3.82 μmol/L, respectively. The hydrolysate of a sample of mixed rumen microorganisms collected before the morning feeding was determined to contain 1.372 μmol/mg microbial nitrogen in the form of Lys. The Lys concentrations of human plasma, goat plasma, human urine, and goat urine were 140.0, 102.0,58.0, and 32.0 μmol/L, respectively.
A Survey of Ochratoxin A and Aflatoxins in Domestic and Imported Beers in Japan by Immunoaffinity and Liquid Chromatography
Authors: Nakajima Masahiro , Tsubouchi Haruo , Miyabe Masaki 
Published: February 2020

Abstract
Analyses of ochratoxin A (OTA) and aflatoxins (AFs) in 94 imported beer samples from 31 producing countries and in 22 Japanese beer samples were performed by immunoaffinity column and reversed-phase liquid chromatography (LC) with fluorescence detection. Recoveries of OTA from beer samples spiked at 25 and 250 pg/mL were 86.1 and 88.2%, respectively. Recoveries of AFs were 98.4 and 98.9%, 95.4 and 95.5%, 101.2 and 97.8%, and 98.9 and 96.0%, respectively, from beer samples spiked at 4.1 and 41 pg AF B1, 4.45 and 44.5 pg AF B2,4.7 and 47 pg AF G1, and 4.65 and 46.5 pg AF G2/mL. Detection limits were 1.0 pg/mL for OTA, 0.5 pg/mL for AFs B1 and B2, and 1.0 pg/mL for AFs G1 and G2. OTA was detected in 86 (91.5%) of 94 imported beer samples at a mean level of 10.1 pg/mL and in 21 (95.5%) of 22 Japanese beer samples at a mean level of 12.5 pg/mL. AF B1 was detected in 11 of 94 imported beer samples at a level of 0.5–83.1 pg/mL and in 2 of 22 Japanese beer samples at 0.5 and 0.8 pg/mL. Except for one beer sample from Peru, the samples contaminated with AFs were also contaminated with OTA. Although OTA was detected in most samples from various countries, AFs were detected in the beer samples from only a limited number of countries where AF contamination might be expected to occur because of their warm climate.
pH-Metric Determination of the Acid Value of Oilseeds without Titration
Authors: Kuselman Ilya , Tur’Yan Yakov I , Bourenko Tat’Yana , Goldfeld Irene , Shenhar Avinoam 
Published: February 2020

Abstract
A pH-metric method for determining the acid values (AVs) of oilseeds in the range 0.6–10 mg KOH/g oil or more has been developed. The method is based on rapid (1–2 min) and complete extraction of free fatty acids from an oilseed test portion into a special reagent A, transfer of an aliquot of the reagent into pH-metric cell with another reagent B, and then measurement of the conditional pH in the mixture of reagents by a glass electrode. Total time for the determination including calculation is 9–10 min. The method is rapid, cheap, simple for automation, and not labor intensive.
Liquid Chromatographic Determination of Fenbendazole Residues in Pig Tissues after Treatment with Medicated Feed
Authors: Capece Bettencourt P S , Pérez Belén , Castells Eugeni , Arboix Margarita , Cristòfol Carles 
Published: February 2020

Abstract
Fenbendazole (FBZ) is an anthelmintic widely used in farm animals to treat parasitic infestations, in pigs, it is administered in the food. The aim of this study was to validate an analytical method for the determination of FBZ and its metabolites in pig tissues. This method is based on oxidation of FBZ and its sulfoxide metabolite to the sulfone metabolite (FBZSO2). The limit of quantitation for this method is 20 ng FBZSO2/g for all tissues. The maximum residue limits (MRLs) established for FBZ and its metabolites in pig tissues are 50 ng/g for muscle, fat, and kidney and 500 ng/g for liver. This method is based on a liquid-liquid extraction followed by an oxidation with peracetic acid and a cleanup procedure based on 2 liquid-liquid extractions. Determination is achieved by high- performance liquid chromatography with ultraviolet detection. The present method is adjusted to the MRL established for FBZ and its metabolite residues. The analysis of the residues shows that after 72 h posttreatment, no FBZSO2 was detected in muscle, fat, and kidney and that liver levels were below the MRL.
Improved Signals Ratio Resolution Method by Optimization of Resolution Function—Simultaneous Determination of Cu(II) and Cd(II) in Water Samples
Authors: Grabarić Zorana , Iveković Damir , Sipos Laszlo , Grabarić Bozidar S 
Published: February 2020

Abstract
From an ecological and economical point of view, it is important to design analytical procedures for monitoring heavy metals in the environment and industrial processes in a way to minimize the use of hazardous reagents and reduce the analysis time. In this paper, a well-known dithizonate extraction-based method for the determination of many metal ions was improved by using chemometrical selectivity of the strongly overlapped spectra of copper and cadmium dithizonates in CCl4 for their simultaneous determination from a single extraction at pH 10. The individual absorption spectra, having absorption maxima difference of only 20 nm, were separated, and the metal ions were quantified by using an improved procedure for optimizing the resolving function in a recently proposed signals ratio method. The procedure consists of using many different resolving functions and plotting the difference of the mean of absolute and nonabsolute mean values of pseudosignals [PDMMV (PS)] against analyte concentrations obtained with each of the resolving functions, thus obtaining 2 straight lines having intersections that give a unique and reliable value of the unknown concentration of the individual analyte in mixture giving strongly overlapped spectra. In this way, the main drawback of the signals ratio resolution method, that is, the visual estimation of optimal resolving function, is eliminated. The proposed parameter, PDMMV (PS), was tested by using both simulated and experimental spectra. Copper was determined in the mixture with ca 20-fold excess of cadmium, and cadmium was determined in ca 10-fold excess of copper at submicromolar concentration levels.
Determination of (–)-Quinine and (+)-Quinidine by Liquid Chromatography with Diode-Laser Polarimetric Detection
Authors: Sánchez Francisco García , Díaz Aurora Navas , Pareja Angeles García , Montiel Germán Cabrera 
Published: February 2020

Abstract
High-performance liquid chromatography using a combination of photometric, fluorimetric, and diode-laser polarimetric detectors in series for the determination of (+)-quinidine and (–)-quinine was investigated. An RP-8 reversed-phase column and methanol-water (80 + 20, v/v) with 0.2% triethylamine as mobile phase at a flow rate of 1 mL/min were used. A dynamic range of 0-200 μg for (+)-quinidine and (+)-quinine was established, with detection limits of 17.0 and 16.7 μg, respectively. An application of this method in spiked rabbit serum was developed.
Determination of Benomyl, Diphenyl, o-Phenylphenol, Thiabendazole, Chlorpyrifos, Methidathion, and Methyl Parathion in Oranges by Solid-Phase Extraction, Liquid Chromatography, and Gas Chromatography
Authors: Yamazaki Yoshie , Ninomiya Takahiro 
Published: February 2020

Abstract
A simple and rapid method was developed for determination of benomyl, diphenyl (DP), o-phenylphenol (OPP), thiabendazole (TBZ), chlorpyrifos, methidathion, and methyl parathion in whole oranges. These compounds were extracted from a mixture of samples and anhydrous sodium acetate with ethyl acetate. The ethyl acetate extract was concentrated and cleaned up by passing through tandem solid-phase extraction columns consisting of anion-exchange and primary/secondary amine bonded silica. The eluate was concentrated and volume was adjusted with methanol for subsequent liquid chromatography (LC) and gas chromatography (GC). Benomyl (as methyl-2-benzimidazole carbamate, MBC), DP, OPP, and TBZ residues were determined by LC with fluorescence detection. Recoveries at 3 fortified levels (0.1,1, and 10 μg/g) ranged from 63.9 to 97.4 %, with coefficients of variation (CVs) of 1.6 to 15.5 %. Limits of detection (LODs) were 0.01 μg/g for DP, OPP, TBZ and 0.05 μg/g for benomyl. Chlorpyrifos, methidathion, and methyl parathion residues were determined by GC with flame photometric detection. Recoveries ranged from 90.4 to 97.0 %, with CVs of 2.1 to 5.9 %. LODs were 0.005 μg/g for chlorpyrifos and methyl parathion, and 0.01 μg/g for methidathion.
Determination of Aldehydes and Ketones in Ambient Air by Micellar Electrokinetic Capillary Chromatography
Authors: Fung Ying-Sing , Long Yen-Hua 
Published: February 2020

Abstract
A new analytical method was developed for determining 14 aldehydes and ketones of environmental interest in ambient air. The method uses 2,4-dinitrophenylhydrazine (DNPH)-coated silica cartridges for sampling, acetonitrile for preconcentration, and micellar electrokinetic capillary chromatography for separation and quantitation. With hydrodynamic sampling of 8.5 cm cartridge for 30 s, applied voltage of 25 kV, detection at 360 nm, and separation in a 60 cm long, 50 μm id fused silica column at ambient temperature (25° ± 1°C) within an electrophoretic buffer (20 mM borate/50 mM sodium dodecyl sulfate at pH 9.2 in 20% [v/v] methanol), baseline separation was obtained for DNPH derivatives of formaldehyde, acetaldehyde, acetone, acrolein, propionaldehyde, butanone, crotonaldehyde, isobutyraldehyde/butyra(dehyde, 2-pentenaldehyde, isovaleraldehyde, valeraldehyde, benzaldehyde, and hexaldehyde. Detection limits [signal-to-noise (S/N) ratio = 2] ranged from 0.10 to 0.77 mg/L, the working range was 0.3-86 mg/L, and the precision as indicated by the relative standard deviation ranged from 2.3 to 6.6% (n = 3). With 1 h sampling at 0.25 L/min and a 1000-fold enrichment, most carbonyl compounds in ambient air can be determined with de- tection limits ranging from 0.008 to 0.1 mg/m3 and a working range of 0.04-11 μg/m3. The developed method was successfully applied to the determination of carbonyl compounds in a chemical laboratory and at street level.
New and improved rotational periods of magnetic CP stars from ASAS-3, KELT, and MASCARA data
Authors: Bernhard Klaus , Hümmerich Stefan , Paunzen Ernst 
Published: February 2020

ABSTRACTMagnetic chemically peculiar (mCP) stars allow the investigation of such diverse phenomena as atomic diffusion, magnetic fields, and stellar rotation. The aim of the present investigation is to enhance our knowledge of the rotational properties of mCP stars by increasing the sample of objects with accurately determined rotational periods. To this end, archival photometric time-series data from the ASAS-3, KELT, and MASCARA surveys were employed to improve existing rotational period information and derive rotational periods for mCP stars hitherto not known to be photometric variables. Our final sample consists of 294 mCP stars, a considerable amount of which (more than 40 per cent) are presented here as photometric variables for the first time. In addition, we identified 24 mCP star candidates that show light variability in agreement with rotational modulation but lack spectroscopic confirmation. The rotational period distribution of our sample agrees well with the literature. Most stars are between 100 Myr and 1 Gyr old, with an apparent lack of very young stars. No objects were found on the zero-age main sequence; several stars seem to have evolved to the subgiant stage, albeit well before the first dredge-up. We identified four eclipsing binaries (HD 244391, HD 247441, HD 248784, and HD 252519), which potentially host an mCP star. This is of great interest because mCP stars are very rarely found in close binary systems, particularly eclipsing ones. Using archival spectra, we find strong evidence that the HD 252519 system indeed harbours an mCP star component.
Two new double-lined spectroscopic binary white dwarfs
Authors: Kilic Mukremin , Bédard A , Bergeron P , Kosakowski Alekzander 
Published: February 2020

ABSTRACT
We present radial velocity observations of four binary white dwarf candidates identified through their overluminosity. We identify two new double-lined spectroscopic binary systems, WD 0311–649 and WD 1606+422, and constrain their orbital parameters. WD 0311–649 is a 17.7 h period system with a mass ratio of 1.44 ± 0.06 and WD 1606+422 is a 20.1 h period system with a mass ratio of 1.33 ± 0.03. An additional object, WD 1447–190, is a 43 h period single-lined white dwarf binary, whereas WD 1418–088 does not show any significant velocity variations over time-scales ranging from minutes to decades. We present an overview of the 14 overluminous white dwarfs that were identified by Bédard et al., and find the fraction of double- and single-lined systems to be both 31 per cent. However, an additional 31 per cent of these overluminous white dwarfs do not show any significant radial velocity variations. We demonstrate that these must be in long-period binaries that may be resolved by Gaia astrometry. We also discuss the overabundance of single low-mass white dwarfs identified in the SPY survey, and suggest that some of those systems are also likely long-period binary systems of more massive white dwarfs.
Using more frequent haemodialysis to manage volume overload in dialysis patients with heart failure, obesity or pregnancy
Authors: Sangala Nicholas , Ficheux Maxence , Fessi Hafedh , Borman Natalie , Collins Allan 
Published: February 2020

Abstract
Managing dialysis in patients with heart failure, pregnancy or obesity is complex. More frequent haemodialysis 5–6 days/week in randomized clinical trials has shown benefits for controlling volume overload, blood pressure and phosphorus, reducing left ventricular hypertrophy (LVH), and improving patient tolerance to therapy. Therapy prescriptions were guided by volume of urea cleared, time-integrated fluid loading control and increased phosphate–β2 microglobulin removal, with greater treatment frequency to address clinical efficacy targets. Case studies in all three categories show that treatment with more frequent haemodialysis in low-dialysate flow systems (Qd &lt;200 mL/min, dialysate of 25–30 L/session, 5–7 days/week for 2.5–3.0 h/session) improves control of heart failure. In pregnancy, treatment 7 days/week with 30 L and 3 h/session of dialysis enabled successful delivery of infants at 32–34 weeks, with all doing well 2–5 years after birth. Obese patients with a body mass index (BMI) &gt;35 achieved control of volume, blood pressure and uraemic symptoms compared to their prior 3 times/week in-centre haemodialysis. Greater application of more frequent haemodialysis should be considered, particularly in high-risk populations, to improve clinical care.
Physical activity and risk of cardiovascular events and all-cause mortality among kidney transplant recipients
Authors: Kang Augustine W , Bostom Andrew G , Kim Hongseok , Eaton Charles B , Gohh Reginald , Kusek John W , Pfeffer Marc A , Risica Patricia M , Garber Carol E 
Published: February 2020

Abstract

Background
Insufficient physical activity (PA) may increase the risk of all-cause mortality and cardiovascular disease (CVD) morbidity and mortality among kidney transplant recipients (KTRs), but limited research is available. We examine the relationship between PA and the development of CVD events, CVD death and all-cause mortality among KTRs.

Methods
A total of 3050 KTRs enrolled in an international homocysteine-lowering randomized controlled trial were examined (38% female; mean age 51.8 ± 9.4 years; 75% white; 20% with prevalent CVD). PA was measured at baseline using a modified Yale Physical Activity Survey, divided into tertiles (T1, T2 and T3) from lowest to highest PA. Kaplan–Meier survival curves were used to graph the risk of events; Cox proportional hazards regression models examined the association of baseline PA levels with CVD events (e.g. stroke, myocardial infarction), CVD mortality and all-cause mortality over time.

Results
Participants were followed up to 2500 days (mean 3.7 ± 1.6 years). The cohort experienced 426 CVD events and 357 deaths. Fully adjusted models revealed that, compared to the lowest tertile of PA, the highest tertile experienced a significantly lower risk of CVD events {hazard ratio [HR] 0.76 [95% confidence interval (CI) 0.59–0.98]}, CVD mortality [HR 0.58 (95% CI 0.35–0.96)] and all-cause mortality [HR 0.76 (95% CI 0.59–0.98)]. Results were similar in unadjusted models.

Conclusions
PA was associated with a reduced risk of CVD events and all-cause mortality among KTRs. These observed associations in a large, international sample, even when controlling for traditional CVD risk factors, indicate the potential importance of PA in reducing CVD and death among KTRs.
TSPO imaging-guided characterization of the immunosuppressive myeloid tumor microenvironment in patients with malignant glioma
Authors: Zinnhardt Bastian , Müther Michael , Roll Wolfgang , Backhaus Philipp , Jeibmann Astrid , Foray Claudia , Barca Cristina , Döring Christian , Tavitian Bertrand , Dollé Frédéric , Weckesser Matthias , Winkeler Alexandra , Hermann Sven , Wagner Stefan , Wiendl Heinz , Stummer Walter , Jacobs Andreas H , Schäfers Michael , Grauer Oliver M 
Published: February 2020

Abstract

Background
Tumor-associated microglia and macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) are potent immunosuppressors in the glioma tumor microenvironment (TME). Their infiltration is associated with tumor grade, progression, and therapy resistance. Specific tools for image-guided analysis of spatiotemporal changes in the immunosuppressive myeloid tumor compartments are missing. We aimed (i) to evaluate the role of fluorodeoxyglucose (18F)DPA-714* (translocator protein [TSPO]) PET-MRI in the assessment of the immunosuppressive TME in glioma patients, and (ii) to cross-correlate imaging findings with in-depth immunophenotyping.

Methods
To characterize the glioma TME, a mixed collective of 9 glioma patients underwent [18F]DPA-714-PET-MRI in addition to [18F]fluoro-ethyl-tyrosine (FET)-PET-MRI. Image-guided biopsy samples were immunophenotyped by multiparametric flow cytometry and immunohistochemistry. In vitro autoradiography was performed for image validation and assessment of tracer binding specificity.

Results
We found a strong relationship (r = 0.84, P = 0.009) between the [18F]DPA-714 uptake and the number and activation level of glioma-associated myeloid cells (GAMs). TSPO expression was mainly restricted to human leukocyte antigen D related–positive (HLA-DR+) activated GAMs, particularly to tumor-infiltrating HLA-DR+ MDSCs and TAMs. [18F]DPA-714–positive tissue volumes exceeded [18F]FET-positive volumes and showed a differential spatial distribution.

Conclusion
[18F]DPA-714-PET may be used to non-invasively image the glioma-associated immunosuppressive TME in vivo. This imaging paradigm may also help to characterize the heterogeneity of the glioma TME with respect to the degree of myeloid cell infiltration at various disease stages. [18F]DPA-714 may also facilitate the development of new image-guided therapies targeting the myeloid-derived TME.