bluuebunny/crossref_metadata_2025 huggingface dataset:
Supercontinuum generated by a femtosecond annular Gaussian beam in air
Authors: Feng ZhiFang , Lan Junping , Li Wei , Liu Xun , Yu ChengXin , Li Jinhong , Liu Yuan
Published: February 2020

We have numerically investigated the supercontinuum generation by a femtosecond annular Gaussian beam in air. Compared with the spectra broadening of the Gaussian filament under the same initial condition, the smooth supercontinuum spectra of the annular Gaussian filament are wide enough to cover the whole visible frequency range in the first focusing cycle. The spectra broadening is analyzed from the frequency shift induced by the ionization and the self-phase modulation. For the blue side of the enhancement of the spectra broadening, the ionization-induced and intensity-induced frequency shifts play the dominant role in the onset distance of the filament and the first maximum value of the spectra broadening, respectively. Then, we have also discussed the influences of the initial pulse energy and the spatial chirp for wide and smooth supercontinuum spectra to cover the whole visible frequency range. Therefore, it is an efficient route to produce the supercontinuum spectra by the annular Gaussian beam.
Numerical analysis of the influence of nonequilibrium plasma on the nucleation rate of supersaturated steam
Authors: Li Sen , Wang Xiaobing , Liu Yang , Cheng Qinglin , Bian Bin , Pu Hui , Ma Tingting , Tang Bo
Published: February 2020

In this paper, a preliminary numerical method is established to simulate the effect of nonequilibrium plasma in water vapor on the nucleation rate of condensation. In this model, the plasma drift-diffusion model is employed to describe the water vapor plasma by considering a set of simplified reaction mechanisms. A heterogeneous condensation model describes the rate of water vapor nucleation on ions. The numerical simulation results show the formation and distribution of charged particles in nonequilibrium plasma and the effect of charged particles on the nucleation rate. The results also show that the nucleation rate increases rapidly with increasing supersaturation due to the presence of nonequilibrium plasma and is significantly higher with plasma than without plasma. The process of plasma-enhanced water vapor nucleation can be simulated quantitatively by this preliminary numerical method.
Two phosphatidylinositol 3-kinase components are involved in interactions between Nicotiana benthamiana and Phytophthora by regulating pathogen effectors and host cell death
Authors: Lu Shan , Yu Jia , Ma Lina , Dou Daolong
Published: February 2020

Phosphatidylinositol 3-phosphate (PtdIns(3)P) has been reported to regulate different physiological processes in plants. PtdIns(3)P is synthesised by the phosphatidylinositol 3-kinase (PI3K) complex which includes common subunits of vacuolar protein sorting (VPS)15, VPS30 and VPS34. Here, we characterised the roles of the important genes NbVPS15, -30 and -34 encoding PI3K components during interactions between Nicotiana benthamiana and Phytophthora pathogens. NbVPS15 and NbVPS34 were upregulated during infection, and plants deficient in these two genes displayed higher resistance to two different Phytophthora pathogens. Silencing NbVPS15 and NbVPS34 decreased the content of PtdIns(3)P in plant cells and the stability of three RxLR (containing the characteristic amino-terminal motif of arginine-X-leucine-arginine, X is any amino acid) effectors. Furthermore, NbVPS15, -30 and -34 were essential for autolysosome formation during Phytophthora capsici infection and limiting programmed cell death (PCD) induced by effectors and elicitors. Taken together, these findings suggest that NbVPS15 and NbVPS34 play a critical role in the resistance of N. benthamiana to Phytophthora pathogens by regulating PtdIns(3)P contents and host PCD.
Changes in the Proportion of Inhibitory Interneuron Types from Sensory to Executive Areas of the Primate Neocortex: Implications for the Origins of Working Memory Representations
Authors: Torres-Gomez Santiago , Blonde Jackson D , Mendoza-Halliday Diego , Kuebler Eric , Everest Michelle , Wang Xiao Jing , Inoue Wataru , Poulter Michael O , Martinez-Trujillo Julio
Published: February 2020

Neuronal spiking activity encoding working memory (WM) is robust in primate association cortices but weak or absent in early sensory cortices. This may be linked to changes in the proportion of neuronal types across areas that influence circuits’ ability to generate recurrent excitation. We recorded neuronal activity from areas middle temporal (MT), medial superior temporal (MST), and the lateral prefrontal cortex (LPFC) of monkeys performing a WM task and classified neurons as narrow (NS) and broad spiking (BS). The ratio NS/BS decreased from MT > MST > LPFC. We analyzed the Allen Institute database of ex vivo mice/human intracellular recordings to interpret our data. Our analysis suggests that NS neurons correspond to parvalbumin (PV) or somatostatin (SST) interneurons while BS neurons are pyramidal (P) cells or vasoactive intestinal peptide (VIP) interneurons. We labeled neurons in monkey tissue sections of MT/MST and LPFC and found that the proportion of PV in cortical layers 2/3 decreased, while the proportion of CR cells increased from MT/MST to LPFC. Assuming that primate CR/CB/PV cells perform similar computations as mice VIP/SST/PV cells, our results suggest that changes in the proportion of CR and PV neurons in layers 2/3 cells may favor the emergence of activity encoding WM in association areas.
Financing Pull Mechanisms for Antibiotic-Related Innovation: Opportunities for Europe
Authors: Årdal Christine , Lacotte Yohann , Ploy Marie-Cécile
Published: February 2020

Antibiotic innovation is in serious jeopardy as companies continue to abandon the market due to a lack of profitability. Novel antibiotics must be used sparingly to hinder the spread of resistance, but small companies cannot survive on revenues that do not cover operational costs. When these companies either go bankrupt or move onto other therapeutic areas, these antibiotics may be no longer accessible to patients. Although significant research efforts have detailed incentives to stimulate antibiotic innovation, little attention has been paid to the financing of these incentives. In this article, we take a closer look at 4 potential financing models (diagnosis-related group carve-out, stewardship taxes, transferable exclusivity voucher, and a European-based “pay or play” model) and evaluate them from a European perspective. The attractiveness of these models and the willingness for countries to test them are currently being vetted through the European Joint Action on AMR and Healthcare-Associated Infections (EU-JAMRAI).
Deregulating antitrust policy
Authors: Stelzner Mark , Chaturvedi Mayuri
Published: February 2020

Starting in the 1980s, market concentration began to rise dramatically decreasing competition and increasing market power for the firms that remain. Such developments have important effects on a number of economic variables such as the efficiency of our economy and income inequality. Thus, it is important to ask: how has the administration of antitrust policy changed over the last half century? To shed more light on these important questions, we explore both change in policy outline by the Department of Justice in its Horizontal Merger Guidelines and change in administrative actions looking at both secondary requests for mergers and acquisitions of different sizes, and pre, post and change in Herfindahl–Hirschman Index in mergers and acquisitions contested by the Department of Justice through the courts.
Integrating bioenergetics and conservation biology: thermal sensitivity of digestive performance in Eastern Collared Lizards (Crotaphytus collaris) may affect population persistence
Authors: Brewster Casey L , Ortega Jason , Beaupre Steven J
Published: February 2020

Information on bioenergetics can provide valuable insight into the ecology, life history and population dynamics of organisms. For ectothermic animals, thermal sensitivity of digestion is an important determinant of net assimilated energy budgets. A recent study in the Ozark Mountains indicated that eastern collared lizards (Crotaphytus collaris) restricted to encroached glades (characterized by woody vegetation encroachment) experience reduced environmental heat loads and have reduced age-specific growth and reproductive rates compared to populations in intact glades. To assess the potential impact of reduced body temperatures on assimilation rates of C. collaris in encroached glades, we conducted feeding trials across four temperature treatments (28, 31, 34 and 37°C). We tested for temperature effects on voluntary feeding rates, passage times, apparent assimilated energy (AE) and metabolizable energy (ME). Passage times decreased and voluntary feeding rates increased significantly with increasing temperature. Consumption explained the majority of variance in AE and ME, followed by the effect of temperature treatments. Using data on voluntary feeding rates, passage times and ME as a function of temperature, we estimated over a 10-fold increase in predicted daily assimilated energy across temperature treatments (28°C = 0.58 kJ/day, 31°C = 1.20 kJ/day, 34°C = 4.30 kJ/day, 37°C = 7.95 kJ/day). Thus, lower heat loads in encroached glades may cause reduced body temperature and result in restricted energy assimilation rates. Our study provides a novel approach to the integration of bioenergetics and conservation and shows the efficacy of using information on digestive performance to investigate underlying mechanisms in a conservation context.
Total arch replacement and frozen elephant trunk for aortic dissection in aberrant right subclavian artery
Authors: Li Jian-Rong , Ma Wei-Guo , Chen Yu , Zhu Jun-Ming , Zheng Jun , Xu Shang-Dong , Liu Yong-Min , Sun Li-Zhong
Published: February 2020

OBJECTIVES

Aortic dissection (AoD) in the presence of an aberrant right subclavian artery (ARSA) is very rare. Clinical experience is limited, and there is no consensus regarding the optimal management strategy. We seek to evaluate the safety and efficacy of the total arch replacement (TAR) and frozen elephant trunk (FET) technique as an approach to AoD in patients with ARSA by retrospectively analysing our single-centre experience.

METHODS

From 2009 to 2017, we performed TAR + FET for 22 patients with ARSA sustaining AoD (13 acute, 59.1%). The mean age was 46.0 years [standard deviation (SD) 8.3], and 19 patients were male (86.4%). ARSA orifice was dilated in 15 (68.2%) patients, and a Kommerall diverticulum was diagnosed in 13 (59.1%) patients with a mean diameter of 21.8 mm (SD 7.7; range 15–40). Surgery was performed via femoral and right/left carotid cannulation under hypothermic circulatory arrest at 25°C. The ARSA was reconstructed using a separate branched graft.

RESULTS

ARSA was closed proximally by ligation in 16 (72.7%) patients, direct suture in 4 (18.2%) patients and both in 2 (9.1%) patients. Operative mortality was 13.6% (3/22). Type Ib endoleak occurred in 1 (4.5%) patient at 8 days. Follow-up was complete in 100% at mean 4.2 years (SD 2.0), during which 3 late deaths and 1 reintervention for type II endoleak occurred. Survival was 81.8% and 76.4% at 3 and 5 years, respectively. Freedom from reoperation was 89.2% up to 8 years. In competing risks analysis, the incidence was 22.1% for death, 10.8% for reoperation and 67.1% for event-free survival at 5 years. The false lumen, ARSA orifice and Kommerall diverticulum were obliterated in 100%. Grafts were patent in 100%. No patients experienced cerebral ischaemia and upper extremity claudication. Hypothermic circulatory arrest time (min) was sole predictor for death and aortic reintervention (hazard ratio 1.168, 95% confidence interval 1.011–1.348; P = 0.034).

CONCLUSIONS

The TAR and FET technique is a safe and efficacious approach to AoD in patients with ARSA. Modifications of routine TAR + FET techniques are essential to successful repair, including femoral and right/left carotid artery cannulation, ligation of ARSA on the right side of the trachea and ARSA reconstruction with a separate graft.
Co-seismic internal deformations in a spherical layered earth model
Authors: Liu Tai , Fu Guangyu , She Yawen , Zhao Cuiping
Published: February 2020

Using a numerical integral method, we deduced a set of formulae for the co-seismic internal deformation in a spherically symmetric earth model, simultaneously taking self-gravitation, compressibility and realistically stratified structure of the Earth into account. Using these formulae, we can calculate the internal deformation at an arbitrary depth caused by an arbitrary seismic source. To demonstrate the correctness of our formulae, we compared our numerical solutions of radial functions with analytical solutions reported by Dong & Sun based on a homogeneous earth model; we found that two sets of results agree well with each other. Our co-seismic internal Green's functions in the near field agree well with the results calculated by the formulae of Okada, which also verifies our Green's functions. Finally, we calculated the Coulomb stress changes on the Japanese Islands and Northeast China induced by the Tohoku-Oki Mw 9.0 earthquake using the methods described above. We found that the effect of layered structure plays a leading role on the near field, while curvature occupies a dominant position on the deep region of the far field. Through a comparison of the Coulomb stress changes at a depth of 10 km on a layered earth model calculated by our method along with the corresponding results of Okada, we found that the discrepancy between them in near field was ∼31.5 per cent, and that of far field was >100 per cent of the signals.
Improving and Developing Analytical Methods ... A Continuing Challenge
Authors: Holak Walter
Published: February 2020

In recognition of his skill at conceiving rugged, elegant analytical methods that have helped further the consumer protection mission of the U.S. Food and Drug Administration (FDA), the 1987 AOAC Harvey W. Wiley Award was presented to Walter Holak at the 101st AOAC Annual International Meeting and Exposition in San Francisco, CA, Sept. 14, 1987. Holak began working for FDA on Dec. 10, 1962, the same year he became a member of AOAC. In the ensuing 25 years, he has developed many methods, perhaps the most significant being those to measure methyl mercury and iodine and that to determine "free" and "total" sulfites in foods. FDA recognized his achievements with a Commendable Service Award in 1979, and in the same year AOAC gave him the double honor of naming him Associate Referee of the Year and electing him a Fellow.
Interactive Effects of Duration of Storage and Addition of Formaldehyde on Levels of
Aflatoxin M1 in Milk
Authors: Heimbecher Susan K , Jorgensen Karen V , Price Ralph L
Published: February 2020

Spray-dried skim milk, naturally contaminated with aflatoxin M„ was added to either raw or pasteurized whole milk to a final concentration of 1.1 Mg aflatoxin M,/L milk. Formalin (37% w/w) was added to the milk solutions to final concentrations of 0, 0.025, 0.05, and 0.1% formaldehyde. Samples were stored in the dark at 21°C in plastic and glass containers and were analyzed for aflatoxin M, at 0,1, 2, 3, and 4 weeks. This experiment was repeated using only raw milk and glass containers. Aflatoxin M, analyses were done at 0, 1, and 2 weeks. Aflatoxin M, losses increased over time and with increased formaldehyde concentration. With both experiments, aflatoxin M, levels after 2 weeks were less than 0.05 iigfL in samples containing 0.1% formaldehyde.
Stability-Indicating Liquid Chromatographic Procedure for Determination of Allantoin in
Cosmetic Lotion
Authors: Trivedi Ramesh J
Published: February 2020

A sensitive, specific liquid chromatographic (LC) procedure was developed for determination of allantoin [(2,5-dioxo-4--imidaazolidinyl) urea or 5-ureidohydantion] in cosmetic lotion. A reverse-phase, ionsuppression mechanism separated allantoin from interfering constituents of the sample matrix, and the compound was determined with a UV detector at 240 nm with a sensitivity limit of ((.20 mg/mL. The chromatographic parameters were optimized for retention time, efficiency, and relative response to the analyte. The assay procedure was validated with spiked laboratory-prepared samples at 100 ± 15% levels. An average recovery of 99.4% with a relative standard deviation of 1.5% (n = 7) was obtained. The stability-indicating characteristics of the method were established by recovery study (99.8%) of samples spiked with known degradation products (urea, allantoic acid, and glyoxylic acid).
Method to Determine Effect of Antibiotics at Residue Levels on R-Factor Transfer
Authors: Sue Brady Marietta , Katz Stanley E
Published: February 2020

An analytical system was developed which can assess the ability of antibiotic/antimicrobial residues (0.01-1.00 ppm) to affect the conjugal transfer of resistance among the Enterobacteriaceae. The donor strain, Escherichia coli RP-4 (Amr Tcr Nmr Km' Lac+), and recipient strain, E. coli Sc-8632 (Smr Lac ), were incubated together in a 1:9 donor : recipient ratio for 18 h with gentle shaking (50 rpm) in brain heart infusion broth in the presence of residue levels of antibiotics. The mating cultures were serially diluted and spread-plated onto MacConkey agar containing 25 ng streptomycin/mL to select the total recipient population of sensitive E. coli Sc-8632 and transconjugants. After an 18 h incubation at 37°C, the plates were replicaplated onto MacConkey agar containing 25 ng ampicillin/mL to select the ampicillin-resistant transconjugant population. Repeatability was good; the average transfer was 51.8%, with a coefficient of variation of 9.3%. Residue levels of tylosin (0.10 and 1.00 ppm) increased the transfer of the ampicillin marker beyond the 95% confidence limits. Oxytetracycline, bacitracin, streptomycin, penicillin, and virginiamycin did not increase the percent transfer. Oxytetracycline at 0.01 ppm decreased the percent transfer. In general, residue levels of antibiotics (0.01-1.00 ppm) did not affect the conjugal transfer of antibiotic resistance.
Microbial Receptor Assay for Rapi d Detection and Identification of Seven Families of
Antimicrobial Drugs in Milk: Collaborative Study
Authors: Charm Stanley E , Chi Ruey
Published: February 2020

A microbial competitive receptor assay for detecting residues of antibiotic families in milk was studied collaboratively by 13 laboratories. The drugs and levels (ppb) tested in this study i nclude penicillin G, 4.8; cephapirin, 5.0; cloxacillin, 100; tetracycline, 2000; chlortetracycline, 2000; oxytetracycline, 2000; erythromycin, 200; lincomycin, 400; clindamycin, 400; sulfamethazine, 75; sulfamethoxazole, 50; sulfisoxazole, 50; streptomycin, 1000; novobiocin, 50; and chloramphenicol, 800. In this method, microbial cells added to a milk sample provide specific binding sites for which 14C or 3H libeled drug competes with drug residues in the sample. The UC or H binding to the specific binding sites is measured in a scintillation counter and compared with a zero standard milk. If the sample is statistically different from the zero standard, it is positive. The assay takes about 15 min. The binding reaction occurs between the receptor site and the drug functional group, so all members of a drug family are detected. In this case, beta-lactams, tetracyclines, macrolides, aminoglycosides, novobiocin, chloramphenicol, and sulfonamides, including/^-aminobenzoic acid (PABA) and its other analogs, are detectable. The incidence of false negative determinations among samples is about 1%; the incidence of false positives is about 3%. For negative cases, the relative standard deviations for repeatability ranged from 0 to 5% and for reproducibility from 0 to 6%. For positive cases, relative standard deviations ranged from 0 to 13% for repeatability and from 0 to 14% for reproducibility. The method has been adopted official first action.
Determination of Trichlorfon in Technical and Powder Formulations
Authors: Slahck Stephen C
Published: February 2020

A facile procedure is described for the determination of trichlorfon in technical material and an 80% powder formulation by using liquid chromatography with ion-pairing and UV detection. Liquid chromatography allows the direct determination of trichlorfon and detection of any dichlorvos present. This method is applicable to quality control and storage stability analyses and eliminates any need for derivatization to counter the thermal lability of trichlorfon. The average standard deviations for the technical and 80% formulation determinations were 0.51 and 0.37%, respectively.
Temperature-Independent Pectin Gel Method for Aerobic Plate Count in Dairy and Nondairy
Food Products: Collaborative Study
Authors: Roth Jonathan N
Published: February 2020

Ten laboratories participated in a collaborative study to compare the pectin-based plate count (PC) Redigel method with the aerobic plate count and standard plate count agar-based standard methods for the estimation of total bacterial counts in 9 different nondairy food and dairy food products. The foods were cream, homogenized milk, raw milk, cheese, raw chicken, raw oysters, frozen broccoli, flour, and spices. Each laboratory analyzed 6 samples (3 sample pairs) of each food group. Counts obtained by the pectin-based plate count and agarbased plate count methods differed significantly (P 0.05) only for homogenized milk, where the pectin gel method resulted in higher counts. The actual counts were higher in the pectin gel method in 8 of the 9 food groups. The log means for pectin gel and agar-based media, respectively, for the 9 food groups were: cream 8.106 and 7.844; homogenized milk 8.642 and 8.231; raw milk 8.711 and 8.423; chicken 7.654 and 7.645; oysters 7.201 and 7.180; broccoli 7.102 and 6.798; cheese 8.045 and 8.055; flour 4.112 and 3.988; spice 5.379 and 5.314. The repeatability standard deviations favored the pectin gel method in 6 of the 9 foods tested. The reproducibility standard deviations favored the pectin gel method in 7 of the 9 foods tested. These results strongly support the suitability of the pectin gel method as an alternative to agar-based plate count and other methods for total bacterial counts in nondairy and dairy food products. The pectin gel method has been adopted official first action.
Multi-Laboratory Study of Measurement of Chlorobiphenyls and Other Organochlorines in Fish Oil
Authors: Uthe John F , Musial Charles J , Misra Raj K
Published: February 2020

Analysts participating in a multi-laboratory comparative study were asked to identify 4 chlorobiphenyls (CBs) supplied in neat form, to measure the amounts of these present in spiked and unspiked fish oil, to measure other CBs and organochlorines in the unspiked fish oil, and to compare results for their own standard solution and those for standard solutions prepared from the supplied CB compounds. Comparisons were done for a common supplied method and the individual methods used in each laboratory. Participants had no trouble identifying 2,2',5,5-tetrachlorobiphenyl, 2,2',4,5,5-pentachlorobiphenyl, and 2,2',4,4',5,5'-hexachlorobiphenyl. Most misidentified 2,2',3,4,5-pentachlorobiphenyl. Approximately one-half of the quantitative comparisons between participants' standards and those prepared from the supplied CBs differed by more than 10%. Two standards prepared from one of the CBs differed by an average of 6.6% (range 0.0-24.5%). Recoveries of added CBs from the fish oil ranged from 24 to 294% for spikes of 63-85 ng/g with no clear distinction between results for the common method vs individual laboratory methods. The common methodology gave a lower coefficient of variation (CV) for most other CBs and organochlorines, but in most cases the CVs for the individual CBs were not smaller than that for Aroclor 1254 equivalents.
Levels and Incidences of Pesticide Residues in Various Foods and Animal Feeds Analyzed by
the Luke Multiresidue Methodology for Fiscal Years 1982-1986
Authors: Luke Milton A , Masumoto Herbert T , Cairns Thomas , Hundley Harvey K
Published: February 2020

During a 5 year period from 1982 to 1986, the FDA Los Angeles District Laboratory analyzed 19 851 samples of domestic and imported food and feed commodities for pesticide residues. A single, rapid, multiresidue method was used. The resultant data have been compiled showing the commodities sampled and the identity and range of levels of pesticide residues detected, including an indication of those residue findings that did not comply with U.S. federal tolerance levels. The residue data presented should not be viewed as being representative of the U.S. food supply; rather, the results are indicative of a surveillance- and compliance-oriented sampling of various food shipments collected by the Los Angeles District.
Supercritical Fluid Chromatography: A New Technique for AOAC
Authors: Knowles David E , Richter Bruce E , Wygant Michele B , Nixon Lori , Andersen Marion R
Published: February 2020

Supercritical fluid chromatography (SFC) is a chromatographic technique that, in many ways, is a hybrid of gas chromatography and liquid chromatography and offers many advantages over both. As this technique continues to grow in use, SFC will become very advantageous to the AOAC analyst.
Liquid Chromatographic Determination of Carhadox in Complete Feeds, Premixes, and Concentrates: Interlaboratory Study
Authors: Aerts René M L , Werdmuller Geziena A
Published: February 2020

A liquid chromatographic (LC) method previously published for the determination of carbadox in finished feeds and premixes was slightly modified and tested in an interlaboratory study. The feed samples are extracted with methanol-acetonitrile (50 + 50) after wetting with water. The extracts are purified over a short alumina column. An aliquot of the eluate is analyzed with reverse phase liquid chromatography with ultraviolet detection. Before the actual interlaboratory study, a prestudy with 2 familiarization feed samples was performed. For the interlaboratory study, 2 series of meal and pelleted samples were prepared with carbadox from different suppliers. Eight collaborating laboratories received 6 feed samples previously milled and ground and 4 pelleted samples which had to be ground by the collaborator's in-house method. Collaborators also received 3 carbadox concentrates (about 10% w/w) and 4 premix samples derived from the concentrates (about 1% w/w). Coefficients of variation under reproducibility conditions were 8.3% for meal samples and 4.9% for pellets. A minor but significant effect was noted for the influence of pelleting temperature on the carbadox content. A minor and insignificant effect was observed for the influence of the milling and grinding procedure on the carbadox content. Alumina cleanup of 1% premixes was not essential, although the resulting chromatograms were cleaner. A slight difference in reproducibility was observed with concentrates (10%) when 0.2 or 0.5 g sample size was used, although the average carbadox concentration found was the same. For premixes and concentrates, coefficients of variation under reproducibility conditions were low, ranging from 2.9 to 7.5%.
Liquid Chromatographic Determination of L-Ascorbic Acid in Candies and Soft Drinks
Authors: Maeda Yumie , Ochi Sumiko , Masui Toshio , Matubara Sourokurou
Published: February 2020

The L-ascorbic acid (AsA) contents of candies and soft drinks available in the market were determined by liquid chromatography (LC). Samples are cleaned up on a disposable Sep-Pak C,„ cartridge followed by reverse phase separation on an ODS column using a mobile phase of 0.1% phosphoric acid (pH 2.2). The AsA peak is detected on the basis of the UV absorption at 254 nm. The detection limit was 1 µg/mL final concentration. Recoveries of AsA added at levels of 1-10 mg/g candy and 1-10 mg/10 mL soft drink were 99.2-101.7% with a coefficient of variation of 0.52-1.20% (n = 5). The present method allows rapid and accurate assays because it is a simple procedure compared with the official dye-titration method, and it is suitable for the routine analysis of AsA in selected candies and soft drinks
Proton Magnetic Resonance Spectroscopic Method for Determination of Phenylbutazone and
Oxyphenbutazone in Tablets
Authors: Husain Sajid , Kifayatullah M , NAGESWARA RAO R
Published: February 2020

A simple, specific, and rapid 'H nuclear magnetic resonance spectroscopic method for the assay of phenylbutazone and oxyphenbutazone is described. Spectra are recorded in CDC13 containing 1,3- dichloro-5-nitrobenzene as an internal standard. The aromatic proton resonances for the standard, at 57.7 and 8.2, are well separated from those of phenylbutazone and oxyphenbutazone, which are in the region of 56.5-7.3 ppm. Average percent recoveries of phenylbutazone and oxyphenbutazone were 98.9 and 98.6 with standard deviations of 0.6 and 0.7, respectively. Commercial formulations were analyzed and the results obtained by the proposed method closely agreed with those found by the British Pharmacopoeia method
Resolution and Analysis of Enantiomers of Amphetamines by Liquid Chromatography on a
Chiral Stationary Phase: Collaborative Study
Authors: Alembik Marc C , Wainer Irving W
Published: February 2020

A rapid, accurate method for separating and determining the enantiomeric composition of amphetamine bulk drug and commercial preparations was developed and subjected to collaborative study. Amide derivatives of the amphetamine enantiomers are formed by using achiral 2-naphthoyl chloride. The resulting enantiomeric amides are then chromatographed on a commercially available chiral stationary phase with hexane-isopropyl alcohol-acetonitrile (97 + 3 + 0.5) mobile phase, with detection at 254 nm. Seven collaborators received bulk drug and commercial samples of amphetamine. The collaborators and authors determined the mean percent /- and rf-amphetamine from 2 injections of each sample. The method can detect the presence of as little as 0.5% of the /-enantiomer in ^-amphetamine, with reproducibility between laboratories of ±71.3%. The method has been adopted official first action for determination of the enantiomeric composition of amphetamine bulk drug and preparations
Spectrophotometric Method for Determination of Phosphine Residues in Cashew Kernels
Authors: Rangaswamy Jois R
Published: February 2020

A spectrophotometric method reported for determination of phosphine (PH3) residues in wheat has been extended for determination of these residues in cashew kernels. Unlike the spectrum for wheat, the spectrum of PH3 residue-AgN03 chromophore from cashew kernels does not show an absorption maximum at 400 nm; nevertheless, reading the absorbance at 400 nm afforded good recoveries of 90- 98%. No interference occurred from crop materials, and crop controls showed low absorbance; the method can be applied for determinations as low as 0.01 ppm PH3 residue in cashew kernels
Comparison of APHA and Elevated Temperature Enrichment Methods for Recovery of
Vibrio cholerae from Oysters: Collaborative Study
Authors: Depaola Angelo , Motes Miles L , Mcphearson Roland M
Published: February 2020

Two methods (the American Public Health Association (APHA) method and the elevated temperature method) for recovery of Vibrio cholerae from oysters were compared in a collaborative study. Oysters were inoculated with high (about 150 cells/g) and low (about 20 cells/ g) levels of V. cholerae. The elevated temperature method gave a significantly higher (P < 0.05) recovery rate and showed greater specificity (P < 0.01), as determined by the confirmation rate of suspect colonies. The elevated temperature method required only 25% of the labor and materials necessary for the APHA method. The elevated temperature method has been adopted official first action.
Liquid Chromatographic Determination of Triamino-5-Triazine in Fertilizer Mixes:
Collaborative Study
Authors: Arcement Billy P , Nathan Levy Iii H
Published: February 2020

A method for measuring the triamino-s-triazine content in various fertilizer mixes has been developed and collaboratively studied. Samples are dissolved in deionized water and analyzed using liquid chromatographic separation on a RP-18 LiChrosorb column. Collaborators analyzed 5 sets of blind duplicates, comparing peak heights to an external standard to quantitate the triamino-s-triazine content. Coefficients of variation ranged from 0.8 to 2.2%. The method has been adopted official first action.
Performance Characteristics of Methods of Analysis Used for Regulatory Purposes. I. Drug
Dosage Forms. F. Gravimetric and Titrimetric Methods
Authors: Margosis Michel , Horwitz William , Albert Richard
Published: February 2020

The original gravimetric and titrimetric methods approved by AOAC for the analysis of pharmaceutical preparations, particularly during the period 1915-1950, show precision, recovery, and outlier parameters approximately the same as those exhibited by the previously reviewed instrumental methods that are currently used. Fifty-nine published collaborative studies utilized gravimetric methods and 85 used titrimetric. The studies of the gravimetric methods encompassed 47 analytes, 95 dosage forms, and 136 assays; the corresponding figures for the titrimetric studies are 72, 112, and 152. An average of approximately 7 laboratories participated per study. The line of best fit of the relative standard deviation between-laboratories (RSDR) plotted against the negative logarithm of the fractional concentration, C, extends from 1.2 and 1.0% for the gravimetric and titrimetric methods, respectively, at 100% concentration to 2.2 and 2.8% at 1.0% concentration. Below this concentration the precision of the titrimetric methods degenerates faster than that of the gravimetric methods. Above about 0.1% concentration the gravimetric and titrimetric methods are somewhat more precise than the instrumental methods in current use for drug analysis. The difference, however, is not statistically significant and the general equation, RSDR = 2 exp(l - 0.5 log C), is also applicable to gravimetric and titrimetric methods above a concentration level of about C = 0.001 (0.1%)
Enzyme Immunoassay for Detection of Drosophila melanogaster Antigens in the Juice of
Various Foods
Authors: Kauffman Peter E , Shah Dhirendra B
Published: February 2020

An enzyme immunoassay (EIA) was developed to identify and quantitate soluble antigens originating from Drosophila melanogaster eggs. Polystyrene microtiter plates were coated with anti-egg antibody. Egg antigen standards or samples were reacted with the sensitized wells. The immobilized antigen was reacted with biotinylated antibody, and the complex was quantitated by an avidin-horseradish peroxidase conjugate. The assay can detect egg antigens equivalent to 0.03 eggs/ mL. The antibody was directed against a number of antigens and cross-reacted with extracts of adult Drosophila melanogaster flies. Homogenized eggs diluted in various juice samples were detectable by EIA. Heating the antigen diluted in buffer or juice at a temperature used in processing of juice reduced the immunological response approximately 40-45%. Brine separated from fresh-packed sauerkraut showed EIA responses equivalent to 0.3-3 eggs/mL. Electrophoretic, chromatographic, and immunological analyses suggested that the EIA responses for sauerkraut brine were related to the Drosophila melanogaster egg antigens
Isolation and Identification of Listeria monocytogenes in Dairy Products
Authors: Lovett Joseph
Published: February 2020

After an outbreak of listeriosis in Massachusetts in 1983, the ability of Listeria monocytogenes to survive in raw and pasteurized milk was investigated. An enrichment broth (EB) containing acriflavine, nalidixic acid, and cycloheximide was used to eliminate overgrowth of the culture by competing organisms, and a modification of McBride's agar (MMA) was used as the isolation medium. The culture was incubated 24 h at 30°C. To isolate Listeria from soft cheese, the incubation period was lengthened to 1 week, and the EB culture was streaked to MMA at 1 and 7 days. Physical and biochemical patterns, the CAMP test, serological tests, and mouse pathogenicity studies were helpful in determining the identity of L. monocytogenes
Development of USDA-FSIS Method for Isolation of Listeria monocytogenes
from Raw Meat and Poultry
Authors: Mcclain Dennis , Lee Wei H
Published: February 2020

A method was developed specifically to detect naturally occurring Listeria monocytogenes in meat because the traditional cold enrichment procedure was extremely slow and other procedures were ineffective. This method could identify beta-hemolytic Listeria colonies in 3-4 days. The use of a 2-stage enrichment, highly selective LPM agar, and a thin-layer horse blood agar plate for the detection of beta-hemolytic Listeria isolates are the important steps of this method. L. monocytogenes was recovered from 20 of 41 samples of frozen ground beef, 12 of 23 samples of pork sausage, and 7 of 22 samples of poultry. These results indicate that L. monocytogenes is common in raw meat and that this method is effective for its recovery
Methodology for Isolation of Listeria from Foods—A Canadian Perspective
Authors: Farber Jeffrey M , Sanders Gregory W , Speirs Joan I
Published: February 2020

A previously described monoclonal antibody-enzyme immunoassay system for dairy products was examined to determine its potential for detecting Listeria in naturally contaminated ground meats. In addition, a microtiter plate system was developed which has potential in the rapid detection of Listeria species in foods. Experience in Canada with the U.S. Food and Drug Administration procedure for dairy products, the cold enrichment procedure, and the U.S. Department of Agriculture procedure for meats is discussed. Also, the status on attempts to devise improved selective media for the isolation of Listeria species from foods is described
Rapid Monoclonal Antibody-Based Enzyme-Linked Immunosorbent Assay for Detection of Listeria in Food Products
Authors: Mattingly Jerome A , Butman Bryan T , Plank Mary C , Durham Rebecca J , Robison Barbara J
Published: February 2020

A rapid diagnostic test for the detection of Listeria in food products has been created. This test, known as Listeria-Tek, uses 2 monoclonal antibodies specific for Listeria in an enzyme-linked immunosorbent assay (ELISA) format. The test requires only 40 h of broth enrichment with no culturing on solid media. It is extremely simple to perform and easy to interpret, and is at least as sensitive and accurate as the best of the culture methods. The test can be used with dairy products, meat products, and environmental samples. The ELISA test is safely performed on the open bench of the laboratory because no live cultures, no radioactivity, no phage, etc., are necessary. There is no need for special licenses or reserved laboratory space, and no waste disposal problems are encountered. If necessary, one technician could easily perform hundreds of assays per day. A printed data sheet is available for permanent records.
First Derivative Spectrophotometric Determination of Anhydrotetracyclines in Tetracyclines
Authors: Wahbi Abdel-Aziz M , Al-Khamees Hamad A , Yousef Ahmad M A
Published: February 2020

A rapid method is presented for detection and determination of anhydrotetracycline- HCl (ATC-HC1) and 4-epianhydrotetracycline-HCl (4-EATC-HCl) in tetracycline-HCl (TC-HCl). The method determines the 2 compounds as a sum, not individually. The first derivative absorption curve has a trough (D1) at 460 nm which is linearly related to concentration (1-10 mg/mL). ATC-HC1 + 4-EATC-HCl content was determined in TC-HCl powder and capsules by the D1 and the compensation D1 spectrophotometric methods. The results were compared with those obtained using U.S. Pharmacopeia and British Pharmacopoeia methods
Liquid Chromatographic Determination of Naringin and Neohesperidin as a Detector of Grapefruit Juice in Orange Juice
Authors: Rouseff Russell L
Published: February 2020

Naringin/neohesperidin ratios can be used to differentiate orange juice which may contain added grapefruit juice from orange juice which may include juices from other naringin-containing cultivars. The naringin/neohesperidin ratios in juice vary from 14 to 83 in grapefruit (C. grandis) and from 1.3 to 2.5 in sour orange (C aurantium) cultivars; the ratio is always 1 for the K-Early tangelo. Concentrations of both naringin and neohesperidin can be determined in orange juice by using a single liquid chromatographic isocratic reverse-phase system with a C-18 column. The detection limit for both compounds is 1 ppm with a linear working range to 500 ppm. Concentration relative standard deviations range from 0.47 to 1.06% for naringin and from 0.4 to 1.27% for neohesperidin. Naringin and neohesperidin recoveries ranged from 93 to 102% at concentrations of 5 and SO ppm. Naringin values from blind duplicate samples of orange/grapefruit juice blends could be duplicated to ± 3%.
Determination of Twenty-one Chloroanisoles in Water and Sediment Samples
Authors: Lee Hing-Biu
Published: February 2020

A simple and sensitive method for the determination of 19 chloroanisoles and 2 chloromethylanisoles was developed for water; another method was developed for sediment samples. Water samples were extracted with dichloromethane; sediments were extracted with a mixture of hexane and acetone in a Soxhlet apparatus. The extracts were concentrated on a Snyder column and then were cleaned up on an activated Florisil column. The anisoles were separated by either an OV-1 or SPB-5 capillary column and were detected by an electroncapture or a mass selective detector. Recoveries of chloroanisoles in fortified water and sediment samples generally ranged between 70 and 85%. The method detection limits were 0.02 /tg/L and 0.002 Mg/g for mono- and di-chloroanisoles in water and sediments and 0.002 jug/L and better than 0.001 jig/g for tri-, tetra-, and pentachloroanisoles in those matrixes. The electron-impact mass spectra of all chloroanisoles exhibited intense peaks for the molecular ions (M+ ), as well as (M - 43)+ and either (M - 15)+ or (M - 30)+ fragments. These masses were used as characteristic ions for quantitative and confirmation purposes.
Liquid Chromatographic-Fluorometric Determination of Cinnamyl Alcohol in Perfumes, Colognes, and Toilet Waters
Authors: Wisneski Harris H , Yates Ronald L , Wenninger John A
Published: February 2020

A liquid chromatographic (LC) method is described for the determination of cinnamyl alcohol (3-phenyl-2-propen-l-ol) in fragrance compositions. The fragrance product is partially cleaned up by diluting the fragrance with a 95% ethanol-water mixture and passing it through a short column containing RP-8 packing. An aliquot of the effluent is then analyzed by LC using an RP-18 column interfaced to a spectrophotofluorometer equipped with double monochromators. The fluorescence emission intensity of the eluted cinnamyl alcohol is measured and compared with that of a standard to calculate the amount of cinnamyl alcohol present. Recoveries from fragrance products fortified with cinnamyl alcohol at levels ranging from 0.0020 to 0.060 mg/mL ranged from 85 to 105% with a mean of 94%. The lowest level of determination was 0.0005 mg/mL.
Determination of ρ-Hydroxybenzoic Acid Esters in Cosmetics by Liquid Chromatography with Ultraviolet and Fluorescence Detection
Authors: Akimoto Noriko , Yamamoto Masatoshi , Sato Shiro , Masui Toshio , Narita Hiroko
Published: February 2020

A simple, precise, and accurate liquid chromatographic method with both ultraviolet (UV) and fluorescence detection is described for the determination of methyl, ethyl, propyl, and butyl />-hydroxybenzoates (PHBA-esters) in cosmetics. sec-Butyl /?-hydroxybenzoate is added to the sample as an internal standard. Then the PHBA-esters are extracted with ether, the ether is evaporated to dryness, and the residue is dissolved in 60% (v/v) acetonitrile. The acetonitrile solution is passed through a Sep-Pak C,8 cartridge to remove co-extracted lipids. PHBA-esters are determined by reverse-phase liquid chromatography with UV detection at 254 nm and fluorescence detection at ex 280 nm, em 305 nm. The mobile phase is acetonitrile-water (35 + 65). The method was linear over the concentration range of 0.005-0.15 mg/mL. Mean recoveries of each PHBA-ester were 98.9- 102.7% (coefficients of variation <2.0°/o).
Determination of Volatile iV-Nitrosamines in Frankfurters Containing Minced Fish and Surimi
Authors: Pensabene John W , Fiddler Walter
Published: February 2020

A method was developed to quantitatively measure volatile /V-nitrosamines, particularly ./V-nitrosodimethylamine (NDMA), in cured minced fish or surimi-meat frankfurters. This method is free from artifact formation. First, 2 dry solid-phase extraction columns are prepared. Solvent is passed through the top column containing the fish-meat into a second column containing acid Celite. The eluate from the Celite column is then passed through a third column containing silica gel. Nitrosamines are eluted from the acid Celite column and then from the silica gel column into the same receiver. Recovery of the internal standard, /V-nitrosoazetidine, added at the 10 ppb level, was 86.5%. In addition, a few samples of nitrite-treated salmon (lox) were also tested for ./V-nitrosamines. The results show that the method is applicable to samples containing nitrite-treated fish and fish-derived products.
Rapid and Selective Method for Quantitation of Metronidazole in Pharmaceuticals
Authors: Sanyal Asis K
Published: February 2020

A selective and highly sensitive assay for /V-1-substituted nitroimidazoles has been modified and adapted for rapid estimation of metronidazole in pharmaceuticals. The color reaction is based on diazotization of sulfanilamide with the nitrite ions liberated by alkaline hydrolysis of metronidazole and subsequent coupling of the diazonium salt with JV-l-(naphthyl)-ethylenediamine dihydrochloride. This method is applicable for the assay of benzoyl metronidazole in oral suspension. Officially recommended excipients and preservatives do not interfere.
Determination of Moisture by Mid Infrared Transmission Spectroscopy
Authors: Van De Voort Frederick R , Laureano Marilou , Smith James P
Published: February 2020

An investigation was undertaken to determine whether commercially available mid infrared filter instrumentation (i.e., Multispec MK1) could be used to determine moisture in a manner similar to the AOAC near infrared method. Using a specially designed IR scanning spectrophotometer capable of working with aqueous systems, functional sample (6.02 jtm) and reference (5.56 iim) wavelengths were determined for quantitating water-methanol mixtures, and a standard curve was derived. Skim milk powder, bread crumbs, and flour were mixed with dry methanol to extract moisture into the solvent; moisture was quantitated relative to 3 AOAC methods. The results indicated that the wavelength pair selected worked well and had the potential to determine moisture content of low moisture food products, given that appropriate moisture extraction protocols were derived. This work indicates that the capabilities of commercial filter-based mid infrared instruments could be expanded to include moisture analyses if such instruments were equipped with the appropriate interference filters to carry out this determination.