bluuebunny/crossref_metadata_2025 huggingface dataset:
Inter- and Intra-laboratory Variability in Rat Growth Assays for Estimating Protein Quality of Foods
Authors: Sarwar Ghulam , Blair Robert , Friedman Mendel , Gumbmann Michael R , Hackler L Ross , Pellett Peter L , Smith Trevor K
Published: February 2020

Protein efficiency ratio (PER), relative PER (RPER), net protein ratio (NPR), relative NPR (RNPR), and nitrogen utilization (NU) methods were investigated in an interlaboratory rat growth study. Six collaborating laboratories studied 7 protein sources (ANRC casein; minced beef; soya assay protein, SAP; pea flour; whole wheat flour, WW; rapeseed protein concentrate, RPC; and egg white solids, EW), and their 10 supplementary or complementary mixtures (casein + Met, SAP + Met, pea flour + Met, WW + Lys, WW + casein, WW + beef, WW + SAP, WW + pea flour, WW + RPC, WW + EW). Test protein(s) were added at the 8% level (N × 6.25). Casein + Met was used as the reference protein. Interlaboratory variation (estimated as between-laboratories coefficients of variation) of PER (up to 17.2%) was greater than that of RPER (up to 14.9%), NU (up to 9.5%), NPR (up to 7.0%), and RNPR, which had the lowest variability (up to 4.7%). In most cases, intralaboratory variation (estimated as within-Laboratories coefficients of variation) for all the methods was less than 5%.
Spectrophotometric Determination of Pentaerythritol Tetranitrate in Tablets
Authors: Shingbal Dattatray M , Agni Ramesh M
Published: February 2020

A sensitive spectrophotometric method is reported for the quantitative determination of pentaerythritol tetranitrate in tablets. The method is based on reduction of pentaerythritol tetranitrate with zinc and calcium chloride, and reaction of the nitroso compound thus formed with 1-naphthylamine in acidic medium. The reaction gives a purple product having an absorbance maximum at 545 nm. Beer's law is obeyed in the concentration range of 1-10 μg/mL of reaction mixture. The presence of meprobamate in tablets does not interfere with the proposed analytical determination.
Instrumental Color Classification of Honey: Collaborative Study
Authors: White Jonathan W ,   Collaborators:, Beaty M R , Eaton W G , Hart B , Huser W , Killion E , Lamssies R R , Lee T , Moen W E , Nelson S L , O'Neal R , Probst J , Shepard G H , Stevenson W V , Teas J
Published: February 2020

A collaborative study was carried out to test the use of the Lovibond 2000 honey color comparator. Fourteen collaborators classified 6 honeys in the test. Results were generally favorable and the method has been adopted official first action.
The Luke et al. Method for Determining Multipesticide Residues in Fruits and Vegetables: Collaborative Study
Authors: Sawyer Leon D
Published: February 2020

Ten laboratories analyzed unfortified and fortified samples of lettuce, tomatoes, and strawberries for organochlorine and organophosphorus pesticides by applicable portions of the comprehensive multipesticide method of Luke et al. The 3 crops were fortified with 6 pesticides, a-BHC, dieldrin, chlorpyrifos, acephate, omethoate, and monocrotophos, each at 3 levels per crop. Included in the 54 fortifications were 16 pairs of blind duplicates: same pesticide, crop, and level. Recoveries were calculated by area comparisons with known reference materials, using the responses obtained from 2 separate element-specific gas chromatographic (GC) systems. The organochlorine pesticides were chromatographed on a methyl silicone column and detected with a Hall 700A electrolytic conductivity detector, and the organophosphorus pesticides were determined with a flame photometric detector after being chromatographed on a specified DEGS column material. Chlorpyrifos was quantitated on both GC systems. Mean recoveries ranged from 82.6% for acephate fortified at 0.5000 ppm in strawberries to 118.1% for 0.0636 ppm fortification of chlorpyrifos in lettuce. Interlaboratory coefficients of variation ranged from 4.0% for 0.6360 ppm fortification of chlorpyrifos in tomatoes to 17.8% for the 0.0636 ppm chlorpyrifos level in lettuce. The procedure features essentially no cleanup before GC and proved comparable to existing multiresidue methods for pesticides of the class types studied, as evidenced by the intra- and interlaboratory measurements of precision and recoveries obtained. The method with the 2 GC systems has been adopted official first action.
Determination of Ethanol in Wine by Titrimetric and Spectrophotometric Dichromate Methods: Collaborative Study
Authors: Pilone Gordon J
Published: February 2020

A dichromate-spectrophotometric method for the determination of ethanol in wine was compared in a collaborative, matched pair study with the AOAC dichromate-titrimetric method, 11.008-11.011. Both methods require distillation of the sample into dichromate. The titrimetric method measures ethanol by titrating the excess dichromate with ferrous ammonium sulfate after conversion of ethanol to acetic acid; the spectrophotometric method directly measures the reduced dichromate formed after oxidation. In addition to comparing the 2 methods, the collaborative study also compared the use of 2 types of assemblies for obtaining the ethanol distillate: the Scott-type, which is used in 11.008-11.011, and the electric Kirk-type. Results of the collaborative study indicated that the repeatability and reproducibility of the official titrimetric method were generally far superior to those of the spectrophotometric method; therefore, adoption of the spectrophotometric method is not recommended. Comparison of titrimetric method results obtained using the 2 types of stills indicated that repeatability and reproducibility were somewhat better when Scott apparatus was used, but measurements using Kirk-type compared well in the range of ethanol concentrations found in table and fortified wines. The Kirk-type distillation apparatus has been adopted official first action as an alternative to Scott apparatus in the dichromate oxidation method for ethanol in wine, 11.008-11.011.
Liquid Chromatographic Determination of Nicarbazin in Feed
Authors: Hurlbut Jeffrey A , Nightengale Cyril T , Burkepile Roger G
Published: February 2020

A liquid chromatographic method was developed for the determination of nicarbazin (4,4'-dinitrocarbanilide.2-hydroxy-4,6-dimethylpyrimidine) in chicken feed. Ground feed was extracted with hot dimethylformamide, filtered, and then cleaned up on an alumina column. The nicarbazin was eluted from the column with ethanol and quantitated using a reverse phase C-18 column, with a methanol-water mobile phase and ultraviolet detection at 344 nm. Recoveries at a typical use level of 100 μg/g feed averaged 98% with a standard deviation of 3%. Samples fortified at levels as low as 0.1 μg/g were analyzed with 92% recovery. The detection limit is 1 ng, and the response is linear between 4 and 1000 ng. Feed additives in combination with nicarbazin do not interfere with recovery.
Thin Layer Chromatographic Determination of Sterigmatocystin in Cheese
Authors: Francis Octave J , Ware George M , Carman Allens , Kuan Shia S
Published: February 2020

A one-dimensional thin layer chromatographic method has been developed for determining sterigmatocystin in cheese. Cheese is extracted with acetonitrile—4% KC1 (85 + 15). A simplified liquid-liquid partition cleanup is used, and the sample extract is passed through a cupric carbonate column for final purification. Sterigmatocystin is visualized by spraying the plate with aluminum chloride. The fluorescence of the : spot is enhanced 10-fold by additional plate spraying with a silicone- ' ether mixture, enabling sterigmatocystin detection and quantitation at 2 land5 μg/kg, respectively. Average recoveries were 88.3 and 86.4% at the 10 and 25 μg/kg levels, respectively.
Assessment of Extraction Procedures in the Analysis of Naturally Contaminated Grain Products for Deoxynivalenol (Vomitoxin)
Authors: Trenholm, Locksley H , Warner Robert M , Prelusky Dan B
Published: February 2020

A comparison of 2 extraction solvent systems (acetonitrile-water, 21 + 4 and methanol-water, 1 + 1) and 3 mixing apparatus (high-speed blender, wrist-action shaker, and mechanical stirrer) was carried out for different extraction time periods. Methods were evaluated using uncontaminated corn spiked with pure deoxynivalenol (DON), fieldinoculated (Fusarium graminearum) corn, and uncontaminated and naturally infected wheat in swine diets. After sample extraction, aliquots were passed through alumina-charcoal cleanup columns, evaporated to dryness, dissolved in 8% aqueous methanol, and injected onto the liquid chromatograph. Results confirm published reports of recoveries from DON-spiked samples; however, longer extraction times (< 120 min) were required for naturally contaminated samples. Use of the high-speed blender resulted in faster extractions, but in our laboratory more samples could be more conveniently extracted simultaneously with the wrist-action shaker or mechanical stirrer. Less carryover (co-extraction) of interfering contaminants was observed when acetonitrile-water was used vs methanol-water. Results emphasize the importance of careful evaluation of extraction procedures with not only spiked samples but also naturally contaminated samples to establish extraction times required for maximum deoxynivalenol recoveries.
pH-Induced Difference, Spectrophotometric Assay of Tetracycline and Oxytetracycline
Authors: Wahbi Abdel-Aziz M , Barary Magda , Mahgoub Hoda , Elsayed M Abdel-Hady
Published: February 2020

The △D1 method is based on the measurement of the quotient of the first order spectrum displacement effect induced by a pH change as a function of tetracycline-oxytetracycline concentration. The linear relationship of such variables with negligible intercept values permits the assay of these drugs in commercial capsule preparations, with good accuracy and reproducibility. The assay results were compared with other spectrophotometric methods: Amax, △A, and D1,
Polarographic Determination and Aqueous Potentiometric Titration of Cimetidine in Tablets
Authors: SÁnchez-PÉrez Ambrosio , HernÁndez-MÉndez, JesÚs , Fuentes De Frutos JosÉ E
Published: February 2020

A method is described which uses the direct current (dc) polarographic behavior of cimetidine in a strong acid solution to determine this compound. The diffusional characteristics of the reduction wave of cimetidine in 1M HC1 (about —0.8 V vs SCE) are shown, and their analytical usefulness was studied. This polarographic method was used to determine cimetidine in standard solutions ranging from 4 to 80 |xg/ mL with a coefficient of variation of 1.3%, and was further applied to the determination of cimetidine in tablets. The results obtained by the dc polarographic method agree with those obtained by an aqueous potentiometric titration of cimetidine with HCI04 and estimation of the end point by the Gran graphic method
Gas Chromatographic Determination of Formaldehyde in Coffee Via Thiazolidine Derivative
Authors: Hayashi Tateki , Reece Clayton A , Shibamoto Takayuki
Published: February 2020

Thiazolidine formed from trace quantities of formaldehyde in an aqueous solution containing cysteamine at pH 8 was extracted with chloroform and subsequently analyzed by a gas chromatograph equipped with a fused silica capillary column and a thermionic nitrogen-phosphorus specific detector. Recoveries of formaldehyde from the aqueous solutions at levels lower than 1 ppm were slightly over 100%. Quantitative analysis of formaldehyde in commercial brewed and instant coffees showed 3.4-4.5 ppm in the brewed and 10-16.3 ppm in the instant coffee.
Indirect Spectrophotometric Method for Determining Epicillin
Authors: Núñez-Vergara Luis J , Roa Alejandro , Squella Juan Arturo , González-Barbagelata Renato V
Published: February 2020

A new UV spectrophotometric assay for determination of epicillin in capsules and plasma is reported. The method is based on the absorptivity of a degradation product obtained from the acidic hydrolysis of the antibiotic. The isolation, identification, individual capsule assays, composite assay, and recovery studies are described. Also, the proposed method is compared with a dc polarographic assay in plasma.
Cranberry Juice Composition
Authors: Hong Victor , Wrolstad Ronald E
Published: February 2020

Eight samples of cranberries (Vaccinium macrocarpon) representing the major varieties and principal commercial growing regions in the United States were processed into juice. Four of the 8 samples were concentrated to 50° Brix. Liquid chromatography (LC) was used to determine nonvolatile organic acid, anthocyanidin pigment, and sugar profiles. Ultraviolet-visible spectral methods were used to determine anthocyanin concentration, polymeric color, and percent polymeric color. Other data presented include stable isotope carbon ratios, degree Brix, pH, and Hunter color parameters. These data are presented to serve as an authentic data base for use in detection of adulterated cranberry juice.
Determination of Diagnostic Levels of Arsenic in Animal Tissue: Collaborative Study
Authors: Hunter R Tracy ,   Collaborators:, D’Andrea G H , Audette R J , Colvin B , George G , Gerlach M , Jain A V , Reagor J , Roof J E , Stahr H M , Tipton B , Weaver P , Willard J
Published: February 2020

The method chosen for this collaborative study is a modification of the AOAC method for As residues, 41.009-41.012. The tissue is dry-ashed overnight at 500°C, and then dissolved in dilute HCl. The solution is diluted and an aliquot is reacted with zinc metal to evolve arsine gas. The gas is trapped in AgDDC solution and As is quantitated at 540 nm. Nine collaborating laboratories performed single analyses on 4 blind duplicate pairs of bovine liver samples which were spiked at 0, 4.3, 10.8, or 21.6 mg As/kg liver. A National Bureau of Standards control (SRM 1566 Oyster Tissue, 13.4 ± 1.9 mg As/kg) and a 1000 mg As/L standard were also submitted to the collaborators. Intralaboratory coefficients of variation ranged from 7.7 to 17.8%; interlaboratory coefficients of variation ranged from 10.9 to 19.0%. The method has been adopted official first action.
Optimum Methanol Concentration and Solvent/Peanut Ratio for Extraction of Aflatoxin from Raw Peanuts by Modified AOAC Method II
Authors: Whitaker Thomas B , Dickens James W , Giesbrecht Francis G
Published: February 2020

The amount of aflatoxin extracted from raw peanuts by using the waterslurry modification of AOAC Method II was determined for 49 different combinations of methanol concentration and solvent/peanut ratio. Results indicate that the amount of anatoxins B1 and B2 extracted from raw peanuts is a function of both methanol concentration and solvent/peanut ratio, and a cubic equation was developed, using regression techniques, to describe the combined effects. From the functional relationship, the predicted methanol concentration and solvent/peanut ratio that extracts the most aflatoxin Bt was computed to be 60.0% and 10.8 mL solvent/g peanuts, respectively. This combination extracted 12.1% more aflatoxin than did AOAC Method II.
Methods of Sample Preparation for Detecting Alkaline Phosphatase in Casein: Collaborative Study
Authors: Murthy Gopala K , Peeler James T ,   Collaborators:, Bassett L , Dickerson B , Dombroski P , McFall D , Marchetti D , Neal D , Reese D
Published: February 2020

A collaborative study was conducted in which 2 different sample preparation techniques were used to determine alkaline phosphatase in casein by the rapid colorimetric test. Seven collaborators tested 10 unknown casein products containing different amounts of residual phosphatase. Results indicated that the phosphatase contents of casein prepared by the 2 methods were not significantly different. The collaborators correctly analyzed 100% of the test samples that were ground and 98 % of the test samples that were unground. The alternative rapid sample preparation method has been adopted official first action.
CuSO4-TiO2 as Kjeldahl Digestion Catalyst in Manual Determination of Crude Protein in Animal Feeds
Authors: Kane Peter F
Published: February 2020

The official AOAC manual Kjeldahl methods for determining crude protein in animal feeds have several disadvantages. For the HgO catalyst method, there are environmental concerns and a lengthy digestion. For the CuS04 catalyst method, the digestion period is shorter, but still 90 min. A different catalyst combination, CuS04-Ti02, makes 40 min digestion feasible. Comparison of these catalysts on a group of representative feeds resulted in a mean difference, Cu-Ti minus HgO, of 0.034% protein. Standard deviation of the differences was 0.36. A Student’s t-test showed no significant difference. The method will be collaboratively studied.
Hydrophobic Grid Membrane Filter Method for Aerobic Plate Count in Foods: Collaborative Study
Authors: Entis Phyllis ,   Collaborators:, Allen J , Bhatnagar A , Brouwer A , Catherwood K , Chrunyk P , Comar P , Cook S , Coulter R , Creighton J , Currie A , Elliott P , Fawcett J A , Haines G , Hall P A , Harrell F M , Harris K , Hopkins K , Jones D , Joy J , Lam J , Lammerding A M , Langford M , Levine D , Myers J , Nelson T , Nielsen P K , Nolan D A , Park M , Pearson C , Pettipas R , Prychitko S , Pryor B M , Rauch W , Reaves L A , Roberts B , Szabo R , Talbot L , Taylor C , Toms S , Wagner C , White S , Wilson P
Published: February 2020

Twenty-one laboratories participated in a collaborative study to validate a hydrophobic grid membrane filter (HGMF) method for aerobic plate count by comparing its performance against the AOAC/APHA pour plate method. Raw milk, raw poultry, whole egg powder, flours, and spices were included in the study. Counts obtained by the HGMF and pour plate methods did not differ significantly, except in the case of whole egg powder, for which the HGMF method produced significantly higher counts. The hydrophobic grid membrane filter method for aerobic plate count in foods has been adopted official first action.
Liquid Chromatographic Determination of Dicofol in Kelthane Formulations: Collaborative Study
Authors: Rothman Alan M ,   Collaborators:, Ausari A , Bennett O O , Blusiewicz E J , Christensen A , Cohen M , Diuguid J , Gentry G M , Grimes G , Harder D , Hitos P , Hodgins W E , Pavel K , Poulsen H H , Rowe N , Sanchez-Rasero F , Stroh S
Published: February 2020

A liquid chromatographic (LC) method was used to determine p,p'- and o,p'-isomers of dicofol AI (active ingredient) in Kelthane® EC and MF formulations. Samples are dissolved in methanol and AI components and impurities are separated on a high resolution C8 column in series with a short C18 guard column, with a methanol-water-acetic acid mobile phase. Cleaned samples are directly injected into the LC system and are monitored at 254 nm. Twelve collaborators submitted results on 5 samples. Using 95% confidence criteria, the average total standard deviation of the total AI across all samples was 2.82%. The method has been adopted official first action.
Nonaqueous Reverse Phase Liquid Chromatographic System for Separation and Quantitation of Provitamins A
Authors: Quackenbush Forrest W , Smallidge Robert L
Published: February 2020

A reverse phase liquid chromatographic (LC) system has been developed for separating the main naturally occurring carotenoids that have provitamin A activity. The system produces baseline separation of β-carotene, α-carotene, and β-cryptoxanthin (β,β-carotene-3-ol, 472- 70-8) from biologically inactive zeinoxanthin (β, ∊-carotene-3-ol, 24480- 38-4) and from a pigment believed to be α-cryptoxanthin (β,∊-carotene- 3'-ol). Some m-isomers are also separated. These separations are obtained on a C-18 column, isocratically, with methanol-chloroform eluant. For quantitation, peak areas from detection at 475 nm are compared with that of an internal standard, l-(phenylazo)-2-naphthalenol (842-07-9), which elutes prior to the provitamins. Provitamin amounts are calculated from absorbance ratios. Prior to LC, esters are saponified, and interfering pigments are removed from ester-free extracts by adsorption on magnesia.
Halogenated Phenols in Water at Forty Canadian Potable Water Treatment Facilities
Authors: Sithole Bishop B , Williams David T
Published: February 2020

Samples of raw and treated water were collected once in each of 3 seasons at 40 potable water treatment plants across Canada and were analyzed for phenol and 33 halogenated phenolic compounds including chlorophenols, bromophenols, bromochlorophenols, and chloroguaiacols. Eighteen of the compounds were not found at any treatment plant; phenol and each of the remaining halogenated phenols were found in at least 1 sample. Pentachlorophenol was the only halogenated phenolic compound found in more than 20% of the raw water samples in the fall and winter samples at levels up to 53 ng/L with mean values of 1.9 and 2.8 ng/L, respectively. No halogenated phenols were detected in raw water summer samples. The halogenated phenols found most frequently in treated water samples were 4-chloro-, 2,4-dichloro-, 2,4,6- trichloro-, and bromodichlorophenols. Mean values were less than 15 ng/L and maximum values seldom exceeded 100 ng/L. Most of the positive values for the treated water samples were found at 8 of the 40 treatment plants but no correlations could be found between halogenated phenol levels and raw water type, treatment process, or chemical dosages.
Graphite Furnace Atomic Absorption Spectrophotometric Determination of 4-Hydroxy-3-Nitrobenzene Arsonic Acid in Finished Animal Feed: Collaborative Study
Authors: George Glenn M , Fra Larry J ,   Collaborators:, Aten C F , Bestianich J , Boucher J , Carr M R , Creekmur R , Hartlieb P , Herald C S , Hunter R T , Kuervers T , Leipzig C , Miller C , Moore E J , Shick L , Sullivan D M , Walton J C
Published: February 2020

Eight laboratories participated in a collaborative study of an atomic absorption spectrophotometric (AAS) method for determination of 4- hydroxy-3-nitrobenzene arsonic acid (roxarsone), which is administered in animal feed at levels of 25-50 ppm as a growth stimulant. The drug is extracted from feed by using aqueous 1% ammonium carbonate solution. Undissolved feed particles are allowed to settle, and then a diluted aliquot of the feed extract is analyzed for total arsenic by AAS using a graphite furnace for sample atomization. Collaborators performed single analyses on 18 samples which were randomly numbered blind duplicate pairs of a complete poultry ration fortified with roxarsone at concentrations from 22.5 to 55.0 ppm. Statistical evaluation of the collaborative data showed satisfactory method performance. Overall mean recovery of roxarsone was 100.4% and the overall relative standard deviation was 6.2%. The method has been adopted official first action.
Gas Chromatographic Determination of Deoxynivalenol in Wheat with Electron Capture Detection: Collaborative Study
Authors: Ware George M , Francis Octave J , Carman Allen S , Kuan Shia S ,   Collaborators:, Bennett G , Carter L , Gaba D , James T , Lyon S , Nowak G , Richelieu M , Routh J , Tarter E , Thorpe C
Published: February 2020

Ten laboratories participated in a collaborative study of a method for the determination of deoxynivalenol in wheat by gas chromatography with electron capture detection. Each laboratory analyzed 6 samples in duplicate. Each collaborator received samples spiked at the 100.3, 501.3, and 1002.6 ng/g levels; a control sample; and 2 naturally contaminated samples. The average recovery (outliers excluded) for the spiked samples was 92.2%. The mean repeatability and reproducibility, respectively, were 32.2 and 41.3% for the spiked samples and 30.9 and 47.6% for the naturally contaminated samples. The method was adopted official first action.
Micro-Kjeldahl Analysis Using 40-Tube Block Digestor and Steam Distillation
Authors: Campbell Duncan C
Published: February 2020

A steam distillation unit was developed for use with a 40-tube block digestor (25 x 290 mm tubes). Initial digestion for 10 min with sufficient H2SO4 alone avoids frothing. A K2SO4/HgO mixture is then added and the digestion is continued. Use of condenser tubes and a fan to cool condensers and the tops of digestion tubes allows the use of high block temperatures (450°C) and long digestion times (1.5 h) with little loss of acid. The steam distillation unit incorporates a large head which contains the steam/sample solution mixture during distillation. The large distillation head allows the acid and base solutions to be sufficiently dilute to avoid a violent reaction when mixed. Distillation was 99.9% complete about 2.2 min after distillate appeared in the condenser. To demonstrate the use of the apparatus, rapeseed (Brassica napus cv. Altex) was ground and forty 0.5 g samples were analyzed giving the following results: mean 23.34%, SD 0.07, CV 0.005%, min. 23.17%, max. 23.46%, range 0.29%. Complete digestion and recovery rate were indicated for nicotinic acid by recovery of 99.9-100.0% of the nitrogen.
Rapid Methods for Determination of Meat Composition
Authors: Mcneal Jon E
Published: February 2020

Rapid analytical procedures are needed to determine the total protein, moisture, and fat content of meat and poultry products. During the past 5 years, the U.S. Department of Agriculture (USDA) has been studying various methods involving instrumentation that test for these constituents either in combination or separately. The studies are initiated on request of the Department or the instrumentation manufacturer and are conducted at the manufacturers' facilities using 2 sets of samples preanalyzed by conventional means. One set, with values, is used for calibration purposes, the other set is tested as unknown samples. The resultant data are evaluated statistically vs the conventional test results. Most studies show the usefulness of these rapid tests for product quality control, but some fall short of regulatory requirements because of unacceptable bias or variability. Typical within-product standard deviations obtained in rapid methods instrumentation tests have ranged from 0.47 to 0.67 for percent total protein, 0.73 to 1.71 for moisture, and 0.41 to 1.14 for fat. For conventional methods, the acceptable USDA performance criteria for repeatability are standard deviations of less than 0.24 for protein, 0.46 for moisture, and 0.63 for fat. Improvements in instrumentation are being made and studies continue.
Detection of Beef and Poultry by Serological Field Screening Tests (ORBIT and PROFIT):
Collaborative Study
Authors: Cutrufelli Mark E , Mageau Richard P , Schwab Bernard , Johnston Ralph W
Published: February 2020

Ten laboratories each analyzed 30 raw meat and raw meat product samples in a collaborative study of the ORBIT (overnight rapid bovine identification test) and PROFIT (poultry rapid overnight field identification test) serological field screening tests for the detection of beef and poultry. Versatility of the tests was shown in the analysis of whole tissue, ground, or emulsified raw meat products. Both tests were demonstrated to be reliable and were capable of detecting adulterants present at the 10% level. The method has been adopted official first actio
A New, Rapid, High-Sensitivity Analysis of Amino Acids in Food Type Samples
Authors: Bidlingmeyer Brian A , Cohen Steven A , Tarvin Thomas L , Frost Beverly
Published: February 2020

A new approach to the analysis of free amino acids and amino acids from hydrolyzed foods is described. The method is based on reaction of the free amino acids with phenylisothiocyanate to form stable derivatives which are subsequently separated by liquid chromatography. Sample preparation procedures are described and results are compared with conventional ion exchange results. Reproducibility of the new method has been determined on a typical food type sample.
Multiresidue Method for Determining Substituted Urea Herbicides in Foods by Liquid Chromatography
Authors: Luchtefeld Ronald G
Published: February 2020

A method is described for determining substituted urea herbicides in foods. The residues are extracted from the product with methanol, and the food coextractives are removed by using solvent partitioning and Florisil column chromatography. The extract is analyzed using liquid chromatography with postcolumn photodegradation, chemical derivatization with orthophthalaldehyde, and spectrofluorometry. Recoveries were determined by spiking 8 different food products with 6 phenylureas—chlorbromuron, chloroxuron, diuron, fluometuron, linuron, and metobromuron—at 0.05 and 0.5 ppm. Three determinations were made at each level for each product. Average recovery at 0.05 ppm was 95% (with a standard deviation of 7.9%), and at 0.5 ppm, 98% (with a standard deviation of 6.9%).
Listeria monocytogenes—A Current Dilemma
Authors: Wehr Michael H
Published: February 2020

Since 1985, Listeria monocytogenes has gone from being an organism known to only a handful of microbiologists to being a fully recognized food-borne pathogen of concern. With nearly unprecedented speed and vigor, food processors, particularly in the dairy industry, and regulatory agencies have reacted in concert to resolve unanswered questions about Listeria so as to assure the safety of the food supply. This report summarizes what has been learned and what is being done
Optimum Conditions for Formation of Aflatoxin Mj-Trifiuoroacetic Acid Derivative
Authors: Stubblefield Robert D
Published: February 2020

Because thin-layer chromatographic (TLC) confirmation of identity and reverse-phase liquid chromatographic (LC) determination with fluorescence detection of aflatoxin M1 both require the derivative formed in the reaction of M1 and trifluoroacetic acid (TFA), various reaction conditions were studied to obtain complete derivative formation. Of the various organic solvents tested, the reaction between M1 and TFA proceeded best in the nonpolar solvents hexane and isooctane. Other parameters investigated were reaction temperature and time, aflatoxin M1 concentration, and solvent volume. The following procedure is considered optimum: 200 μL each of hexane and trifluoroacetic acid are mixed with M1 standard in a silylated glass vial or with milk residue in a regular glass vial with a Teflon-lined screw cap and heated 10 min at 40°C. The mixture is evaporated to dryness under N2, and the derivative is saved for TLC or LC. No unreacted aflatoxin M1 was detected by reverse-phase LC after this procedure was incorporated for analysis of milk samples.
Optimization of Chick Embryotoxicity Bioassay for Testing Toxicity Potential of Fungal Metabolites
Authors: Prelusky Dan B , Hamilton Robert M G , Foster Brian C , Trenholm Locksley H , Thompson Brian K
Published: February 2020

The optimization of a simple, sensitive procedure using a chick embryotoxicity screening test (CHEST) bioassay for detection of toxic compounds is presented. Dosing protocols of eggs, using several mycotoxins (aflatoxin B„ deoxynivalenol, T-2 toxin) and appropriate controls, were evaluated for embryonic sensitivity, overall practicality of the procedure, and consistency of results. It was found that both type of carrier solvent and volume injected could significantly affect overall embryonic mortality. The chick embryo was most sensitive to the effects of toxins and solvents after 1 or 2 days of incubation; a rapid decrease in response was observed as the age of the embryo at dosing increased. Following administration of the toxins just below the shell membrane by way of a small hole (<0.5 mm diameter) punched in the shell, a good dose-response (°/o mortality) could be obtained regardless of the site of injection (except directly into the yolk), although dosing via the air sac position resulted in a slightly better statistical outcome. Although some variations in calculated LD50 values were found among repeated assays, statistical analyses showed that the differences were not due to dosing protocol but to the variations in embryo sensitivities among batches of eggs. Thus, if standard reference toxins for comparison are run concurrently, the CHEST assay can prove to be a very satisfactory model, as well as having considerable flexibility to be adapted to the needs and resources of many laboratories.
Fecal bacterial community of finishing beef steers fed ruminally protected and non-protected active dried yeast
Authors: Ran Tao , Jiao Peixin , AlZahal Ousama , Xie Xiaolai , Beauchemin Karen A , Niu Dongyan , Yang Wenzhu
Published: February 2020

Our previous study suggested that supplementation of high-grain diets with ruminally protected and non-protected active dried yeast (ADY) may potentially reduce manure pathogen excretion by feedlot cattle. We hypothesized that feeding ruminally protected ADY might change the fecal bacterial community of finishing cattle. The objective of this study was to investigate the effects of feeding ruminally protected and non-protected ADY to finishing beef steers on their fecal bacterial community. Fresh fecal samples were collected on day 56 from 50 steers fed one of five treatments: 1) control (no monensin, tylosin, or ADY), 2) antibiotics (ANT, 330 mg monensin + 110 mg tylosin·steer−1d−1), 3) ADY (1.5 g·steer−1d−1), 4) encapsulated ADY (EDY; 3 g·steer−1d−1), and 5) a mixture of ADY and EDY (MDY; 1.5 g ADY + 3 g EDY·steer−1d−1). Bacterial DNA was extracted from fecal samples and sequenced using a MiSeq high-throughput sequencing platform. A total number of 2,128,772 high-quality V4 16S rRNA sequences from 50 fecal samples were analyzed, and 1,424 operational taxonomic units (OTU) were detected based on 97% nucleotide sequence identity among reads, with 769 OTU shared across the five treatments. Alpha diversity indices, including species observed, Chao estimate, abundance-based coverage estimator, Shannon, Simpson, and coverage, did not differ among treatments, and principal coordinate analysis revealed a high similarity among treatments without independent distribution. Bacteroidetes and Firmicutes were dominant phyla in the fecal bacterial community for all treatments, with a tendency (P < 0.10) for greater relative abundance of Bacteroidetes but lesser Firmicutes with ANT, EDY, and MDY compared with control steers. Prevotella was the dominant genus in all treatments and steers supplemented with ANT, EDY, and MDY had greater (P < 0.05) relative abundance of Prevotella than control steers, but lesser (P < 0.03) relative abundance of Oscillospira. No differences between ADY and control were observed for the aforementioned variables. Fecal starch contents were not different among treatments, but the relative abundance of Bacteroidetes, as well as Prevotella at genera level, tended (P < 0.06) to be positively correlated to fecal starch content. We conclude that supplementing ruminally protected or non-protected ADY or ANT had no effect on diversity and richness of fecal bacteria of finishing beef cattle, whereas feeding protected ADY or ANT to finishing beef steers altered the dominant fecal bacteria at phylum and genus levels. Therefore, supplementation of ruminally protected ADY may potentially improve intestinal health by stimulating the relative abundance of Prevotella.
Characterization of a caffeoyl-CoA O-methyltransferase-like enzyme involved in biosynthesis of polymethoxylated flavones in Citrus reticulata
Authors: Liu Xiaojuan , Zhao Chenning , Gong Qin , Wang Yue , Cao Jinping , Li Xian , Grierson Donald , Sun Chongde
Published: February 2020

Polymethoxylated flavones (PMFs), which accumulate exclusively in fruit peel of citrus, play important physiological and pharmacological roles but the genetic basis for the methylation of flavonoids has not been fully elucidated in citrus. Here we characterize a caffeoyl-CoA O-methyltransferase-like enzyme, designated CrOMT1. The expression pattern of CrOMT1 was highly correlated with the concentration of the three major PMFs in two different citrus fruit tissues during fruit maturation. Exposure of fruit to UV-B radiation sharply increased the level of CrOMT1 transcripts and also led to the accumulation of three PMFs. The potential role of CrOMT1 was studied by testing the catalytic activity of recombinant CrOMT1 with numerous possible substrates in vitro. The enzyme could most efficiently methylate flavones with neighboring hydroxy moieties, with high catalytic efficiencies found with 6-OH- and 8-OH-containing compounds, preferences that correspond precisely with the essential methylation sites involved in the synthesis of the three naturally occurring PMFs in Citrus reticulata. This indicates that CrOMT1 is capable of in vitro methylation reactions required to synthesize PMFs in vivo. Furthermore, transient overexpression of CrOMT1 increased levels of the three major PMFs in fruit, indicating that CrOMT1 is likely to play an essential role in the biosynthesis of PMFs in citrus.
The Structure of Bias
Authors: Johnson Gabbrielle M
Published: February 2020

What is a bias? Standard philosophical views of both implicit and explicit bias focus this question on the representations one harbours, for example, stereotypes or implicit attitudes, rather than the ways in which those representations (or other mental states) are manipulated. I call this approach representationalism. In this paper, I argue that representationalism taken as a general theory of psychological social bias is a mistake, because it conceptualizes bias in ways that do not fully capture the phenomenon. Crucially, this view fails to capture a heretofore neglected possibility of bias, one that influences an individual’s beliefs about or actions toward others, but is, nevertheless, nowhere represented in that individual’s cognitive repertoire. In place of representationalism, I develop a functional account of psychological social bias which characterizes it as a mental entity that takes propositional mental states as inputs and returns propositional mental states as outputs in a way that instantiates social-kind inductions. This functional characterization leaves open which mental states and processes bridge the gap between the inputs and outputs, ultimately highlighting the diversity of candidates that can serve this role.
From Essence to Necessity via Identity
Authors: Leech Jessica
Published: February 2020

An essentialist theory of modality claims that the source of possibility and necessity lies in essence, where essence is (obviously) then not to be defined in terms of necessity. Hence such theories owe us an account of why it is that the essences of things give rise to necessities in the way required. A new approach to understanding essence in terms of the notion of generalized identity promises to answer this challenge by appeal to the necessity of identity. I explore the prospects for this approach, and argue that it fails. If one favours an account of essence in terms of generalized identity, then one will not, I argue, be able to satisfactorily defend an essentialist theory of modality against the challenge; if one wishes to defend an essentialist theory of modality, and thereby to give an explanation of how necessity arises from essence, one should not understand essence in terms of generalized identity.
LECX: a cubesat experiment to detect and localize cosmic explosions in hard X-rays
Authors: Braga J , Durão O S C , Castro M , D’Amico F , Stecchini P E , Amirábile S , Gonzalez Blanco F , Strauss C , Silva W , Schad V R , Reitano L A
Published: February 2020

With the advent of the nanosat/cubesat revolution, new opportunities have appeared to develop and launch small (∼1000 cm3), low-cost (∼US$ 1M) experiments in space in very short time frames (∼2  yr). In the field of high-energy astrophysics, in particular, it is a considerable challenge to design instruments with compelling science and competitive capabilities that can fit in very small satellite buses, such as a cubesat platform, and operate them with very limited resources. Here, we describe a hard X-ray (30–200 keV) experiment, LECX (‘Localizador de Explosões Cósmicas de Raios X’ – Locator of X-Ray Cosmic Explosions), that is capable of detecting and localizing within a few degrees events like gamma-ray bursts and other explosive phenomena in a 2U-cubesat platform, at a rate of ∼5 events per year. In the current gravitational wave era of astronomy, a constellation or swarm of small spacecraft carrying instruments such as LECX can be a very cost-effective way to search for electromagnetic counterparts of gravitational wave events produced by the coalescence of compact objects.
Unprecedented and highly stable lithium storage capacity of (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture for high-performance Li-ion batteries
Authors: Yu Wen-Bei , Hu Zhi-Yi , Jin Jun , Yi Min , Yan Min , Li Yu , Wang Hong-En , Gao Huan-Xin , Mai Li-Qiang , Hasan Tawfique , Xu Bai-Xiang , Peng Dong-Liang , Van Tendeloo Gustaaf , Su Bao-Lian
Published: February 2020

Active crystal facets can generate special properties for various applications. Herein, we report a (001) faceted nanosheet-constructed hierarchically porous TiO2/rGO hybrid architecture with unprecedented and highly stable lithium storage performance. Density functional theory calculations show that the (001) faceted TiO2 nanosheets enable enhanced reaction kinetics by reinforcing their contact with the electrolyte and shortening the path length of Li+ diffusion and insertion-extraction. The reduced graphene oxide (rGO) nanosheets in this TiO2/rGO hybrid largely improve charge transport, while the porous hierarchy at different length scales favors continuous electrolyte permeation and accommodates volume change. This hierarchically porous TiO2/rGO hybrid anode material demonstrates an excellent reversible capacity of 250 mAh g–1 at 1 C (1 C = 335 mA g–1) at a voltage window of 1.0–3.0 V. Even after 1000 cycles at 5 C and 500 cycles at 10 C, the anode retains exceptional and stable capacities of 176 and 160 mAh g–1, respectively. Moreover, the formed Li2Ti2O4 nanodots facilitate reversed Li+ insertion-extraction during the cycling process. The above results indicate the best performance of TiO2-based materials as anodes for lithium-ion batteries reported in the literature.
A self-consistent leptonic–hadronic interpretation of the electromagnetic and neutrino emissions from blazar TXS 0506+056
Authors: Cao Gang , Yang Chuyuan , Yang Jianping , Wang Jiancheng
Published: February 2020

The potential association between the blazar TXS 0506+056 and the neutrino event IceCube-170922A provides a unique opportunity to study the possible physical connection between high-energy photons and neutrinos. We explore the correlated electromagnetic and neutrino emissions of blazar TXS 0506+056 by a self-consistent leptonic–hadronic model, taking into account particle stochastic acceleration and all relevant radiative processes self-consistently. The electromagnetic and neutrino spectra of blazar TXS 0506+056 are reproduced by the proton synchrotron and hybrid leptonic–hadronic models based on the proton–photon interactions. It is found that the hybrid leptonic–hadronic model can be used to better explain the observed X-ray and $\gamma$-ray spectra of blazar TXS 0506+056 than the proton synchrotron model. Moreover, the predicted neutrino spectrum of the hybrid leptonic–hadronic model is closer to the observed one compared to the proton synchrotron model. We suggest that the hybrid leptonic–hadronic model is more favored if the neutrino event IceCube-170922A is associated with the blazar TXS 0506+056.
Untangling the Value Premium with Labor Shares
Authors: Donangelo Andres
Published: February 2020

This paper quantifies the relative importance of labor-induced operating leverage at explaining the value premium. I extend a traditional variance decomposition methodology using labor shares to disentangle labor leverage from the value premium and from the value spread and from the variation in profitability levels and growth. My extended decomposition shows that labor leverage explains approximately 50% of the value premium, whereas profitability and growth-based mechanisms explain the other 50%. I propose a tractable production-based asset-pricing model that qualitatively and quantitatively explains this finding, as well as the relation between book-to-market ratios, discount rates, profitability, and future growth.
‘My Master and Friend’: Social Networks and Professional Identity in American Medicine, 1789–1815
Authors: Naramore Sarah E.
Published: February 2020

Between 1789 and 1813, over 3,000 men received medical instruction in Philadelphia from physician and educator Benjamin Rush. Despite the fact that on average students remained for only 1.4 years of formal education, this cohort of American doctors formulated a national and professional identity grounded in shared experiences and fostered through interpersonal networks. This essay argues that a networked approach to studying early American doctors will provide more robust information about the development of a distinctive American medical profession in the nineteenth century. Using large data sets gleaned from manuscript sources this project uncovers patterns of migration and communication for otherwise invisible American medical men.
A Survey of Systematic Evidence Mapping Practice and the Case for Knowledge Graphs in Environmental Health and Toxicology
Authors: Wolffe Taylor A M , Vidler John , Halsall Crispin , Hunt Neil , Whaley Paul
Published: February 2020

Systematic evidence mapping offers a robust and transparent methodology for facilitating evidence-based approaches to decision-making in chemicals policy and wider environmental health (EH). Interest in the methodology is growing; however, its application in EH is still novel. To facilitate the production of effective systematic evidence maps for EH use cases, we survey the successful application of evidence mapping in other fields where the methodology is more established. Focusing on issues of “data storage technology,” “data integrity,” “data accessibility,” and “transparency,” we characterize current evidence mapping practice and critically review its potential value for EH contexts. We note that rigid, flat data tables and schema-first approaches dominate current mapping methods and highlight how this practice is ill-suited to the highly connected, heterogeneous, and complex nature of EH data. We propose this challenge is overcome by storing and structuring data as “knowledge graphs.” Knowledge graphs offer a flexible, schemaless, and scalable model for systematically mapping the EH literature. Associated technologies, such as ontologies, are well-suited to the long-term goals of systematic mapping methodology in promoting resource-efficient access to the wider EH evidence base. Several graph storage implementations are readily available, with a variety of proven use cases in other fields. Thus, developing and adapting systematic evidence mapping for EH should utilize these graph-based resources to ensure the production of scalable, interoperable, and robust maps to aid decision-making processes in chemicals policy and wider EH.
A stranger among us: the occurrence of Cantellius (Balnoidea: Pyrgomatidae) an epibiont of scleractinias in stylasterids (Hydrozoa)
Authors: Zweifler Adi , Simon-Blecher Noa , Pica Daniela , Chan Benny K K , Roth Jonathan , Achituv Yair
Published: February 2020

Barnacles that fit morphologically into the description of the pyrgomatid genus Cantellius were retrieved from hydrozoan Stylasteridae. The use of molecular markers also confirmed the assignment of these barnacles to the genus Cantellius. Hitherto, stylasterids have not been recorded as hosts of pyrgomatids. This finding conflicts with and refutes the statement that scleractinans (Hexacorallia) are obligatory hosts of pyrgomatids. These are the first unequivocal records of living pyrgomatids in stylasterids, thus documenting a new type of habitat for this group of barnacles. Further inspections of stylasterids will probably reveal more new host records and, possibly, new pyrgomatids.