bluuebunny/crossref_metadata_2025 huggingface dataset:
Positive Effect of Chaiqin Wendan Decoction on Anxiety and Depression Model Rats
Authors: Li Xiaobing , Li Xinmin , Cai Ruijuan , Qi Binbin , Li Yuzhu , Wang Tian , Liu Wen , Chen Wenyu , Chen Yan , Ma Mengge , Ren Shicheng , Liu Xiaomei , Liang Xuejiao , Wang Dexing , Shen Guangbin , Zhang Huxiao , Zhang Bing
Published: February 2020

Objectives: To investigate the effect of Chaiqin Wendan Decoction (CWD) and mechanisms for anxiety and depression-like behavior in rats. Methods: We divide SD male rats into four groups randomly (blank group, model group, diazepam group and Chinese medicine group). The anesity and depression model rats were induced by chronic unpredictable emotional stress. Chinese medicine group and diazepam group were given CWD and diazepam respectively. The model group and the blank group were given the same amount of normal saline per day. The general state of the rats was recorded, and an open field trial and operation of the Morris water maze test were performed.the concentration of 5-HT was measured. Results: Compared with the model group, the body weight, horizontal movement distance score, number of upright, and target quadrant percentage of the rats in the Chinese medicine group increased significantly (P <0.05), and the latency decreased significantly (p <0.05). The concentration of 5-HT in the Chinese medicine group and diazepam group was significantly decreased by ELISA kit (P<0.05).Conclusion:WD can significantly promote the learning and cognitive ability of rats with anxiety and depression. Its mechanism of action may be closely related to the ability of CWD to reduce 5-HT concentration.
Conventional Bridge Damage Identification Based on BP Neural Network
Authors: Yang Zeying , Zhang Yalei , Wang Yaping , Wang Ning , Cui Haina , Qu Yongye
Published: February 2020

Aiming at the problem of insensitivity of damage identification in conventional bridges, the application of BP neural network in long-span bridges is studied, and it is extended to the field of damage identification of conventional bridges. The finite element models of three-span continuous variable cross-section box girders under intact and damaged conditions are established by Midas civil, and the eigenvalues of bridges under different conditions are analyzed. It is found that in conventional bridges, the sensitivity to structural damage is: mode > vertical displacement > natural frequency. The parameterized natural frequencies and modes of structures are used as input of BP neural network, and the damage location and degree are used as output to train the neural network. Then, the damage location and degree are identified under different working conditions, and the results show that the recognition effect is not satisfactory. Analyzing the reason, the natural frequency and modal shape of the structure will change when the conventional bridge is damaged, but the deformation value is very small. When training the BP neural network, it is easy to appear over-fitting, which results in poor recognition effect. Therefore, it is difficult to identify structural damage by using BP neural network through acquiring the characteristics of conventional bridges. It is still necessary to study appropriate damage identification parameters and methods that can be applied to conventional bridges.
On Broadband Nonlinear Piezoelectric Energy Harvesting Techniques
Authors: Sun Chuahua , Shang Guangqing
Published: February 2020

With the development of portable electronic devices, internet of things, micro-electromechanical system (MEMS) and wireless sensor networks, mirco sources and self-powered devices have been attracted great attention. It is an effective way to supply mirco power or realize the miniaturization of the device via the piezoelectric energy harvesting effect. Therefore, research on piezoelectric energy harvesting techniques has been highly valued. To enhance adaptability and improve harvesting efficiency, the broadband nonlinear piezoelectric energy harvesting technique turns to be a research hotspot. The current status of broadband nonlinear piezoelectric energy harvesting technique with nonlinear stiffness was reviewed according to methods of realizing nonlinearity. The characteristics and existed problems of each kind of nonlinear harvester were then concluded. The nonlinear piezoelectric energy harvester with nonlinear stiffness has a good prospect if its advantages can be given full use.
Progress of Airborne Lidar of Ocean Chlorophyll Observations Including Algorithm and Instruments
Authors: Li Yongzhi , Yu Kun , Zhang Wenkai , Li Dan , Zhao Zheng , Jiang Xiao , Jin Dingjian , Shang Boxuan , Wang Houmao
Published: February 2020

Airborne lidar is widely used to measure water depth, organic matter, chlorophyll, seabed topography and seabed types et al. The water depth observation has been studied for many years by many scientists, while the Chlorophyll retrieval by airborne lidar is studied by a few scientists. In this paper, the progress of measurements of Chlorophyll by use of airborne lidar is discussed, which includes the progress of retrieval algorithm, international instruments, and Chinese instruments.
Analysis of Climate and Water Resources Characteristics in Chongqing
Authors: Chen Rong , Wang Jinglan , Zhang Weihua
Published: February 2020

Due to the impact of climate change, the spatial and temporal distribution of water resources has also changed accordingly. We want to know the response of Chongqing’s water resources to climate change. By using the methods of linear regression and cumulative anomaly, this paper analyses the meteorological data of Chongqing from 1951 to 2018 and the climatic and hydrological conditions in recent years. It is found that Chongqing is in a period of high temperature and rainy weather under the influence of global warming, and is very prone to drought and flood disasters. This study can show the climate and water resources changes in Chongqing in the future to some extent and help the local authority for designing and operating the hydrological sensitive facilities.
Construction of Air Pollution Monitoring and Pre-Warning Platform—Taking Daming County, Handan City, Hebei Province as an Example
Authors: Qian Huan , Yue Jianwei , Li Jingze , Ding Kesong
Published: February 2020

Based on GIS technology, computer hardware and software and network communication technology, an air pollution monitoring and pre-warning platform is constructed. It helps to monitoring air pollution situation in Daming county and analysis the data from monitoring sites about AQI, PM
2.5 and other five kinds of air quality index. By using this platform, people can intuitively find where is the main air pollution source and the air quality forecast around all county.
The Numerical Simulation of Gas-Liquid Two Phase Flow in Annular Gap Venturi of Converter Wet Dust Removal
Authors: Ye Mengmeng , Liang Mei , Qian Fuping , Lu Jinli
Published: February 2020

Based on the CFD-DPM method, the numerical simulation of gas-liquid two phase flow in annular gap venturi with different annular gap trip and liquid/gas ratio at the same gas flow rate was carried out in this paper. The results show that the pressure drop at the contraction section of venturi accounts for about 75% of the total pressure drop, and the pressure drop at the throat is about 20% of the total pressure drop. The average velocity of flue gas at the throat ranges from 106 to 192m/s. The total pressure drop of the venturi is proportional to the liquid/gas ratio at the constant annular gap trip, and the larger the annular gap trip, the greater the effect of the liquid/gas ratio on the pressure drop. As the annular gap trip is 800∼900mm, the effect of liquid/gas ratio on the pressure drop is significant. The total pressure drop of the venturi and the droplets concentration at the venturi inlet are proportional to the annular gap trip at the constant liquid/gas ratio, and the growth rate of the pressure drop is greater with the annular gap trip as the annular gap trip is larger than 700mm. In addition, the growth rate of the droplets concentration at the venturi outlet also increases with the annular gap trip.
Distribution Features of Phytoplankton and Its Correlation with Environmental Factors of Baima Lake
Authors: Wang Jun , Wu Sushu , Fan Bowen , Chen Wenmeng
Published: February 2020

In order to deal with the degradation of ecological function in Baima Lake, 11 Sampling sites were set up in 2014, 2016 and 2017 in Huaian City, Jiangsu Province. Sampling was conducted monthly to monitor and analyze the temporal and spatial changes of phytoplankton community structure in the lake. The results showed that 119 species of phytoplankton were identified in 2014, 109 species in 2016 and 114 species in 2017, belonging to 8 phyla. Phytoplankton abundance got top in summer and bottom in winter. Its spatial distribution was higher in northwest and central, and lower in northeast and south. The health status of lakes in different years was evaluated by Shannon-Wiener diversity index, Pielou evenness index and SI pollution index. Baima Lake is a medium-eutrophic (moderate) water body. Pearson correlation analysis was carried out between phytoplankton and environmental factors.
Study on Ecological Vulnerability of Dianchi Lake Basin Based on GIS-Based Principal Component Analysis
Authors: Ma Xiaoliang , Peng Shuangyun , Lin Cong , Lin Zhiqiang , Zhou Yanlian
Published: February 2020

Ecological vulnerability is one of the key concerns of global environmental change, sustainable development, and human-land relations. This paper takes the Dianchi Basin as a research area, uses GIS principal component analysis method, selects relevant index factors to determine the weight, and finally combine evaluation index model to comprehensively analyze the ecological vulnerability of the Dianchi Basin. After research, it is found that: ①The ecological vulnerability of the Dianchi Basin is relatively high as a whole, of which 69.72% of the ecological vulnerability grades are above Grade 3. ②The ecologically fragile areas in the Dianchi Basin are generally scattered and concentrated in a small area, and the closer to the area of Dianchi, the higher the vulnerability level. ③The ecological vulnerability of the Dianchi Basin is the result of multiple factors. The research has reference significance for the ecological construction and economic development of Dianchi Basin in the future.
Analysis of Disturbance Factors in Zhalong Wetland Landscape Dynamics
Authors: Yang Yuqing , Gong Adu , Zhang Yuhong , Chen Yanling , Zeng Tingting
Published: February 2020

Based on remote sensing image data and meteorological data, this paper analyzes dynamic landscape disturbance factors of zhalong wetland through landscape pattern index and other methods, the results show that: (1) In recent 40 years, zhalong wetland landscape type pattern space, landscape fragmentation phenomenon is more serious.(2) The total area of swamp continues to decrease, and the bare land and cultivated land also show a decreasing trend, but the grassland and water area increase.(3) The temperature fluctuation, precipitation change and the government’s policy of building railways and ditches have a profound impact on the landscape pattern of wetland.(4) At the early stage of the study, zhalong wetland landscape dynamic influencing factors are mainly natural factors such as temperature and precipitation;Since the 1990s, human activities such as government building of railways, highways, ditches and other factors have gradually increased the impact on wetland landscape dynamics.
Comparative Study on Several Determination Methods of Chlorophyll Content in Plants
Authors: Li Jing , Zhou Xiaoyan , Zhou Jiaping , Shang Ran , Wang Yu , Jing Pei
Published: February 2020

Chlorophyll was determined in the N,N-dimethylformamide (DMF) and the mixture solution (Valcohol/Vacetone=1:1) respectively, and the extracted effects were compared. The results showed that the extracted effects of chlorophyll content in the mixture solution method is better than that of DMF method when the chlorophyll content was low, while DMF method is better when the chlorophyll content was high. DMF extraction method with long extraction time was better to the coniferous forest vegetation and Ginkgo biloba Linn., because the plant’s well-developed cuticle on the blade surface could hinder the dissolution of chlorophyll in the extract in a short time. The SPAD values were measured when leaves were determined by above two methods meanwhile, and were linearly fitted with the actual chlorophyll content values to obtain the linear correction equation. It found that SPAD values had a good linear relationship with chlorophyll content (with mg/dm2 fresh weight, R2 > 0.96). Linearity range of SPAD value is 25∼60 in DMF method, and 26∼50 in the mixture solution method.
A Survey on Multi-Product Sustainable Economic Production Quantity Model Considering Wastewater Emission Costs
Authors: Chiang Li Yu-Hua , Sy L L , Lomibao K C , German J D , Wee H M
Published: February 2020

Implementing sustainability in production processes is the goal of many companies. A traditional economic production quantity (EPQ) model is used to determine the optimal number of products to produce in one period. Few researchers have considered carbon emission costs. In this study, we made a survey on multi-product sustainable economic production quantity model considering wastewater emission costs. The objective of this study is investigate the possible research to determine the economic production quantity to minimize the total costs per production cycle and waste emissions. The survey consider researches under three scenarios: (1) sustainable EPQ model that considers all CO2 emissions from inventory holding and production; (2) sustainable EPQ with shortage backorder; and (3) multi-product sustainable EPQ model with shortage.
Jason-1 Observation of Typhoon Storm Surge and Analysis Based on Numerical Simulation
Authors: Qiu Zhou , Zheng Gang , Yang Jingsong , Han Guoqi , Li Xiaohui , Zhang Chuanzheng , Zhou Lizhang , Wang Yan
Published: February 2020

Storm surge is one of the most disastrous marine disasters to coastal regions. It is greatly essential to research on storm surge and mitigate this damage. In our paper, Typhoon hit the Japan Coast on 31 July, 2004. Jason-1 and two tide-gauge stations all captured the obvious sea level anomalies. The magnitude of this storm surge was approximately 0.4 m. We further used the Unstructured Grid Finite-Volume Community Ocean Model (FVCOM) to simulate this storm surge. The method based on the relationships between the maximum wind speed of best track and that of CFSR data was adopted to reconstruct wind field. This method reduced the root mean squared error (RMSE) from 0.11 m to 0.07 m at Owase station. The accuracy was improved by 35%. Similar to Owase station, the RMSE was reduced from 0.085 m to 0.06 m at Cape Muroto station. The accuracy was improved by 30%.
Mechanical, physical and biodegradability performances of treated and untreated groundnut shell powder recycled polypropylene composites
Authors: Usman Mohammed Awwalu , Momohjimoh Ibrahim , Usman Abdulhafiz Onimisi
Published: February 2020

In this study, groundnut shell powder (GSP) was used for the reinforcement of recycled polypropylene (recycled PP). The GSP consisting of two-particle sizes viz (0–250 μm and 250–420 μm) was partly treated with sodium hydroxide at room temperature and the GSP both treated and untreated were compressed and compounded with recycled PP to produce GSP-recycled PP composites. For comparison, recycled PP was equally produced as a control sample. The effects of GSP addition and sodium hydroxide treatment on recycled PP were investigated through the mechanical testing of the developed composites. The mechanical properties (tensile strength, hardness, and toughness) of the composites were evaluated and the tensile strength of both treated and untreated GSP-recycled PP composites is higher than the recycled PP and the treated GSP of particle size 0–250 μm having the highest tensile strength at 25 wt% GSP in recycled PP matrix. The hardness of the recycled PP increases with increasing content of GSP while the toughness decreases with increasing concentration of GSP in the recycled PP matrix. The water uptake of the GSP-recycled PP composites was equally studied, and the results revealed that the treated GSP-recycled PP composites has lower rate of water absorption as compared to untreated GSP-recycled PP composites Thermal stability and crystallinity of the composites and monolithic recycled PP were investigated, and it was discovered that the thermal stability and crystallinity of the polymer were enhanced with GSP addition. Morphological characterization of the selected samples through a scanning electron microscope (SEM) and x-ray diffraction (XRD) were equally done to validate the mechanical performance of the composites. Finally, biodegradability study on the composites and the control sample was conducted and it was found out that, the addition of GSP in both forms promotes the biodegradation of the recycled PP polymer. Such biodegradable GSP-recycled PP polymer composite materials are highly valuable for manufacturing food takeaway packages and some of the interior parts of the automobiles.
Performance and Utilization of a Laboratory-Developed Nucleic Acid Amplification Test (NAAT) for the Diagnosis of Pulmonary and Extrapulmonary Tuberculosis in a Low-Prevalence Area
Authors: Das Sanchita , Mangold Kathy A , Shah Nirav S , Peterson Lance R , Thomson Richard B , Kaul Karen L
Published: February 2020

Objectives

Tuberculosis (TB) is a significant global health problem. In low-prevalence areas and low clinical suspicion, nucleic acid amplification tests (NAAT) for direct detection of Mycobacterium tuberculosis complex (MTBC) can speed therapy initiation and infection control. An NAAT assay (TBPCR) targeting MTBC IS6110 is used for detecting MTBC in our low-prevalence population.

Methods

Fifteen-year review of patient records identified 146 patients with culture-positive pulmonary tuberculosis (PTB) or extrapulmonary tuberculosis (EPTB). Laboratory-developed TBPCR was retrospectively compared with standard stain and cultures for PTB and EPTB diagnoses.

Results

TBPCR assay was used in 57% of patients with PTB and 33% of patients with EPTB. TBPCR detected 88.4% of all TB (smear-positive, 97%; smear-negative, 79%) with 100% specificity. Low bacterial load was indicated in TBPCR-negative PTB (P = .002) and EPTB (P < .008).

Conclusions

TBPCR performance was optimum but significantly underused. Guidelines are proposed for mandated use of TBPCR that capture patients with clinically suspected PTB. Focused TBPCR use in low prevalence populations will benefit patient care, infection prevention, and public health.
Simulating the effects of local adaptation and life history on the ability of plants to track climate shifts
Authors: Moran Emily V
Published: February 2020

Many studies have examined the impact of dispersal on local adaptation, but much less attention has been paid to how local adaptation influences range shifts. The aim of this study was to test how local adaptation might affect climate-driven range shifts in plants, and if this might differ between plants with different life histories. Simulated range shift dynamics were compared for hypothetical annual, perennial and tree species, each comprised of either one plastic genotype or six locally adapted genotypes. The landscape consists of shifting climate bands made up of 20 × 20 m patches containing multiple individuals. Effects of seed dispersal, breadth of the plastic species’ tolerance, steepness of the climate gradient and rate of the climate shift are also examined. Local adaptation increased the equilibrium range size and aided range shifts by boosting fitness near range edges. However, when the rate of climate change was doubled on a steep gradient, locally adapted trees exhibited a higher percent loss of range during the climate shift. The plastic annual species with short dispersal was unable to recover its range size even after the climate stabilized, while the locally adapted annuals tracked climate change well. The results suggest that in most situations local adaptation and longer dispersal distances will be advantageous, though not necessarily sufficient, for tracking suitable climates. However, local adaptation might put species with long generation times at greater risk when climate shifts are very rapid. If confirmed by empirical tests, these results suggest that identifying variation between species in how fitness varies along climate gradients and in these key demographic rates might aid in prioritizing management actions.
Computational methods for predicting 3D genomic organization from high-resolution chromosome conformation capture data
Authors: MacKay Kimberly , Kusalik Anthony
Published: February 2020

The advent of high-resolution chromosome conformation capture assays (such as 5C, Hi-C and Pore-C) has allowed for unprecedented sequence-level investigations into the structure–function relationship of the genome. In order to comprehensively understand this relationship, computational tools are required that utilize data generated from these assays to predict 3D genome organization (the 3D genome reconstruction problem). Many computational tools have been developed that answer this need, but a comprehensive comparison of their underlying algorithmic approaches has not been conducted. This manuscript provides a comprehensive review of the existing computational tools (from November 2006 to September 2019, inclusive) that can be used to predict 3D genome organizations from high-resolution chromosome conformation capture data. Overall, existing tools were found to use a relatively small set of algorithms from one or more of the following categories: dimensionality reduction, graph/network theory, maximum likelihood estimation (MLE) and statistical modeling. Solutions in each category are far from maturity, and the breadth and depth of various algorithmic categories have not been fully explored. While the tools for predicting 3D structure for a genomic region or single chromosome are diverse, there is a general lack of algorithmic diversity among computational tools for predicting the complete 3D genome organization from high-resolution chromosome conformation capture data.
Simple is sometimes better: a test of the transferability of species distribution models
Authors: Haulsee Danielle E , Breece Matthew W , Fox Dewayne A , Oliver Matthew J
Published: February 2020

Species distribution models (SDMs) are often empirically developed on spatially and temporally biased samples and then applied over much larger spatial scales to test ecological hypotheses or to inform management. Underlying this approach is the assumption that the statistical relationships between species observations and environmental predictors are applicable to other locations and times. However, testing and quantifying the transferability of these models to new locations and times can be a challenge for resource managers because of the technical difficulty in obtaining species observations in new locations in a dynamic environment. Here, we apply two SDMs developed in the Mid-Atlantic Bight for Atlantic sturgeon (Acipenser oxyrhynchus oxyrhynchus) to the South Atlantic Bight and use an autonomous underwater vehicle to test model predictions. We compare Atlantic sturgeon occurrence to two SDMs: one associating sturgeon occurrence with simple seascapes and one developed through coupling occurrences with environmental predictors in a generalized additive mixed model (GAMM). Our analysis showed that the seascape model was transferable across these disparate regions; however, the complex GAMM was not. The association of the imperilled Atlantic sturgeon with simple seascapes allows managers to easily integrate this remotely sensed dynamic oceanographic product into future ecosystem-based management strategies.
Linezolid resistance in Enterococcus faecium and Enterococcus faecalis from hospitalized patients in Ireland: high prevalence of the MDR genes optrA and poxtA in isolates with diverse genetic backgrounds
Authors: Egan Sarah A , Shore Anna C , O’Connell Brian , Brennan Grainne I , Coleman David C
Published: February 2020

Objectives

To investigate the prevalence of the optrA, poxtA and cfr linezolid resistance genes in linezolid-resistant enterococci from Irish hospitals and to characterize associated plasmids.

Methods

One hundred and fifty-four linezolid-resistant isolates recovered in 14 hospitals between June 2016 and August 2019 were screened for resistance genes by PCR. All isolates harbouring resistance genes, and 20 without, underwent Illumina MiSeq WGS. Isolate relatedness was assessed using enterococcal whole-genome MLST. MinION sequencing (Oxford Nanopore) and hybrid assembly were used to resolve genetic environments/plasmids surrounding resistance genes.

Results

optrA and/or poxtA were identified in 35/154 (22.7%) isolates, the highest prevalence reported to date. Fifteen isolates with diverse STs harboured optrA only; one Enterococcus faecium isolate harboured optrA (chromosome) and poxtA (plasmid). Seven Enterococcus faecalis and one E. faecium harboured optrA on a 36 331 bp plasmid with 100% identity to the previously described optrA-encoding conjugative plasmid pE349. Variations around optrA were also observed, with optrA located on plasmids in five isolates and within the chromosome in three isolates. Nine E. faecium and 10 E. faecalis harboured poxtA, flanked by IS1216E, within an identical 4001 bp region on plasmids exhibiting 72.9%–100% sequence coverage to a 21 849 bp conjugative plasmid. E. faecalis isolates belonged to ST480, whereas E. faecium isolates belonged to diverse STs. Of the remaining 119 linezolid-resistant isolates without linezolid resistance genes, 20 investigated representatives all harboured the G2576T 23S RNA gene mutation associated with linezolid resistance.

Conclusions

This high prevalence of optrA and poxtA in diverse enterococcal lineages in Irish hospitals indicates significant selective pressure(s) for maintenance.
Determination of Carbon Dioxide Evolution Rates Using a Novel Noninstrumental Microrespirometer
Authors: Hsieh Yuch-Ping , Hsieh Yun-Hwa P
Published: February 2020

A novel noninstrumental microrespirometer was developed to determine carbon dioxide evolution rates of solid or liquid samples at μL/h levels accurately and rapidly. The respirometer is based on the simple principle of acid–base titration at a steady-state of carbon dioxide absorption/evolution. The structure and operation of the microrespirometer are simple and the cost is modest in comparison to instrumental methods. The microrespirometer is suitable for laboratory studies and field routine examinations of food, agricultural, and environmental samples.
Rapid Enzyme-Linked Immunoassay for Detection of Salmonella in Food and Feed Products: Performance Testing Program
Authors: Bolton Frederick J , Fritz Erica , Poynton Sharon , Jensen Torben
Published: February 2020

The BIOLINE Salmonella ELISA Test for Salmonella spp., which is a rapid, easy, and convenient assay was evaluated for use in detecting Salmonella in foods and feeds. Each food matrix or feed was artificially contaminated with low levels of Salmonella. Twenty different matrixes were studied and 20 different Salmonella strains from a broad variety of serogroups (B, C, D, E, F, G, H, I, M, O, P, and U) were used. The ELISA Test kit detected levels as low as 1 cfu/25 g sample with at least 4 of the 20 matrixes tested. The test kit is applicable to all sample types tested. The BIOLINE Salmonella ELISA Test kit has been granted AOAC–RI performance tested status.
Identification of Smoked Atlantic Salmon (Salmo salar) and Rainbow Trout (Oncorhynchus mykiss) Using PCR-Restriction Fragment Length Polymorphism of the p53 Gene
Authors: Carrera Esther , García Teresa , Céspedes Ana , González Isabel , Fernández Alicia , Asensio Luis M , Hernández Pablo E , Martín Rosario
Published: February 2020

Raw and smoked samples of Atlantic salmon (Salmo salar) and rainbow trout (Oncorhynchus mykiss) were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) of the p53 gene. DNA from S. salar and O. mykiss was amplified by using primers flanking exons 5 to 6 of the p53 nuclear gene. PCR products of different length were obtained for each species (532 and 518 base pairs, respectively). Sequences of PCR products obtained from S. salar and O. mykiss were compared in the search for polymorphic restriction sites. The restriction fragments obtained with Eco RV, Hinf I, and Taq I endonucleases showed interspecific polymorphism, making it a useful method for identification of Atlantic salmon and rainbow trout.
Validation of a Method for Determination of Phospholipase A2 and Melittin in Bee Venom Preparations by Capillary Electrophoresis
Authors: Pacáková Vêa , Ŝtulík Karel
Published: February 2020

A method was validated for the determination of the 2 main components of bee venom, phospholipase A2 and melittin, by capillary electrophesis (CE). Optimum resolution and selectivity were attained with a running electrolyte of 150 mM phosphoric acid, pH 1.8. The repeatability and day-to-day reproducibility of the migration times were better than 0.36 and 2.8%, respectively. The repeatability and day-to-day reproducibility of the normalized peak areas were better than 1.3 and 2.6%, respectively. The response of the UV detector at 190 nm was linear over < 2 concentration decades, from 0.05 to 1.5 mg/mL, with correlation coefficients of 0.9994 for phospholipase A2 and 0.9997 for melittin. The limits of detection and quantitation were 4.5 and 15 μg/mL, respectively, for phospholipase A2 and 1.6 and 6 μg/mL, respectively, for melittin. The reproducibility of the measurements with 2 different CE instruments was satisfactory; the mean concentration and relative standard deviation (RSD) values for phospholipase A2 and melittin were 14.4% (RSD, 1.3%) and 51.4% (RSD, 1.1%), respectively, with instrument I; the corresponding values with instrument II were 14.5% (RSD, 2.8%) and 52.3% (RSD, 2.2%). The accuracy was estimated by comparison with a liquid chromatographic (LC) method. Differences between the CE and LC measurements were attributed to irreversible adsorption of the analytes on the LC column. The recoveries of phospholipase A2 and melittin with the CE method were 98.8 and 101.7%, respectively.
Determination of the Levels of Isoflavonoids in Soybeans and Soy-Derived Foods and Estimation of Isoflavonoids in the Japanese Daily Intake
Authors: Nakamura Yumiko , Tsuji Sumiko , Tonogai Yasuhide
Published: February 2020

The levels of 6 kinds of isoflavonoids found in 11 domestic and imported soybeans, and 12 kinds of soybean-based processed foods in Japan were systematically analyzed, and the Japanese daily intake of isoflavonoids from those foods was estimated. The total isoflavonoids (daidzein, glycitein, and genistein) were analyzed with acid hydrolysis and the intact isoflavonoids (daidzein, glycitein, genistein, daidzin, glycitin, and genistin) were analyzed without hydrolysis. This was followed by cleanup with an ODS cartridge column and determined by liquid chromatography with a diode array detector. The highest content of isoflavonoids was found in kinako (a roasted soybean powder) and the lowest was found in soy sauce. The contents and composition of the isoflavonoids in the 11 soybeans varied by species and country of origin. The level of isoflavonoids found in the processed foods varied by manufacturing method or ingredients. The percentage of aglycone tended to be higher in miso (fermented soybean paste) and soy sauce, which are heated and fermented during the manufacturing process. Japanese daily intake of isoflavonoids from soybeans and soybean-based processed foods was estimated as 27.80 mg per day (daidzein 12.02 mg, glycitein 2.30 mg, and genistein 13.48 mg).
Analysis of Pesticide Residues in Mixed Fruit and Vegetable Extracts by Direct Sample Introduction/Gas Chromatography/Tandem Mass Spectrometry
Authors: Lehotay Steven J
Published: February 2020

Direct sample introduction (DSI), or “dirty sample injection,” was investigated in the determination of 22 diverse pesticide residues in mixed apple, green bean, and carrot extracts by benchtop gas chromatography/tandem mass spectrometry (DSI/GC/MS–MS). The targeted pesticides, some of which were incurred in the samples, included chlorpyrifos, azinphos-methyl, parathion-methyl, diazinon, terbufos, p,p′-DDE, endosulfan sulfate, carbofuran, carbaryl, propargite, bifenthrin, dacthal, trifluralin, metalaxyl, pendimethalin, atrazine, piperonyl butoxide, diphenylamine, vinclozolin, chlorothalonil, quintozene, and tetrahydrophthalimide (the breakdown product of captan). The analytical DSI method entailed the following steps: (1) blend 30 g sample with 60 mL acetonitrile for 1 min in a centrifuge bottle; (2) add 6 g NaCl and blend 30 s; (3) centrifuge for 1–2 min; (4) add 5 mL upper layer to 1 g anhydrous MgSO4 in a vial; and (5) analyze 11 μL extract, using DSI/GC/MS–MS. Sample cleanup is not needed because GC/MS–MS is exceptionally selective for the targeted analytes, and nonvolatile coextracted matrix components do not contaminate the injector or the GC/MS–MS system. Average recoveries of the pesticides were 103 ± s7% with relative standard deviations of 14 ± 5% on average, and limits of detection were <2 ng/g for nearly all pesticides studied. The DSI/GC/MS–MS approach for targeted pesticides is quantitative, confirmatory, sensitive, selective, rugged, rapid, simple, and inexpensive.
Determination of Chlormequat in Pears by Liquid Chromatography/Mass Spectrometry
Authors: Mol Hans G J , Dam Ruud C J Van , Vreeken Rob J , Steijger Odile M
Published: February 2020

A straightforward and reliable method was developed for the determination of chlormequat in pears by liquid chromatography/mass spectrometry (LC/MS). Water and methanol were compared as extraction solvents. Because no significant differences in extraction efficiency or repeatability were found, water was chosen as the extraction solvent. The extracts were analyzed without cleanup by either an ion-trap liquid chromatograph/mass spectrometer in the single MS mode or a triple-quadrupole instrument in the MS/MS mode, using electrospray ionization. Both instruments were equally suitable for quantitation and confirmation of identity. Recoveries were 76–103%, and reproducibility was ≤12%. The lowest detection limit (0.007 mg/kg) was obtained with the triple-quadrupole instrument in the MS/MS mode.
Quantitative Determination of Diethylene Glycol Contamination in Pharmaceutical Products
Authors: Baffi Patricia , Elneser Suria , Baffi Myrna , Melin Matilde De
Published: February 2020

A simple, rapid, and reliable method was developed for the quantitative determination of diethylene glycol (DEG) in pharmaceutical products using capillary gas chromatography with flame ionization detection. The method uses ethylene glycol as internal standard and allows for the separation of propylene glycol and DEG. The assay was linear in a DEG concentration range between 1.0 and 10.00 mg/mL, with coefficients of variation of 2.3–4.4% for the tested concentrations. Quantitation and detection limits, respectively, were 1.0 mg/mL and 0.15 mg/mL diethylene glycol. The method was used to analyze 3 pharmaceutical products possibly contaminated with diethylene glycol, of which one was suspected of causing intoxication and death in children. Infrared spectroscopy was used to confirm the identity of diethylene glycol. This analytical methodology is proposed for evaluation of pharmaceutical products containing glycols to prevent intoxication and for security level verification.
Equivalence of Visual Immunoprecipitate Assay (VIP®) for Salmonella for the Detection of Motile and Nonmotile Salmonella in All Foods to AOAC Culture Method: Collaborative Study
Authors: Feldsine Philip T , Mui Linda A , Forgey Robin L , Bargholz J , Kerr David E ,   Collaborators:, Al-Hasani S , Arling V , Beatty S , Bohannon J , Brannan J , Brown N , Bryant J , Burford M , Chavez C , Chinault K , Cooan N , Copeland F , Dixon L , Fitzgerald S , Franke W , Frissora R , Gailbreath K , Godon S , Good M , Ha T , Hagen H , Hanson S , Johnson K , Koch S , Leung S , Lienau A , Lin J , Lin S , Marolla B , Maycock L , McDonagh S , Miller L , Otten N , Post R , Resutek J , Rice B , Richter D , Ritger C , Schwantes D , Simon J , Smith J , Smith S , Stokes R , Thibideau J , Tuncan E , Uber D , Van Landingham V , Vrana D , West D
Published: February 2020

Six foods representative of a wide variety of processed, dried powder processed, and raw food types were analyzed by the Visual Immunoprecipitate Assay (VIP®) for Salmonella and AOAC INTERNATIONAL culture method. Paired samples of each food type were simultaneously analyzed; one sample by the VIP method and one by the AOAC culture method. A total of 24 laboratories representing federal government agencies and private industry, in the United States and Canada, participated in this collaborative study. Food types were inoculated with species of Salmonella with the exception of raw ground chicken, which was naturally contaminated. No statistical differences (p < 0.05) were observed between VIP for Salmonella interpretation and the AOAC culture method for any inoculation level of any food type or naturally contaminated food. The method was adopted Official First Action status by AOAC INTERNATIONAL.
Isolation of Alicyclobacillus acidoterrestris from Fruit Juices
Authors: Walls Isabel , Chuyate Rolenda
Published: February 2020

K agar, a novel isolation medium developed for the food industry, was compared with other acidified media for isolation of Alicyclobacillus acidoterrestris spores. Spores were inoculated into apple juice, orange juice, and a fruit juice blend and then isolated on the following media: K agar, pH 3.7; semi-synthetic medium, pH 4.0; orange serum agar, pH 3.5; and minimal salts medium, pH 4.0. Media were incubated at 24, 35, 43, and 55°C. Highest recovery of spores was obtained with either K agar or semi-synthetic medium, incubated at 43°C. The effect of heat shocking spores at different times was also determined; heat shocking at 80°C for 10 min was considered appropriate. Peptone, previously shown to inhibit A. acidoterrestris, was not inhibitory when present in K agar. A collaborative trial with 9 laboratories was undertaken to determine the repeatability and reproducibility of counts on K agar. K agar prepared from individual components was compared with dehydrated K agar prepared by International BioProducts (Redmond, WA). There were no significant differences between log mean counts for the 2 media for each of the juices analyzed at both the high and the low inoculum levels. Repeatability and reproducibility values were not significantly different either within juices, within trials, or across all samples tested in both trials. K agar is suitable for isolation of A. acidoterrestris spores from fruit juices.
Revalidation and Long-Term Stability of National Institute of Standards and Technology Standard Reference Materials 1566, 1567, 1568, and 1570
Authors: Anderson David L , Cunningham William C
Published: February 2020

Multiple units of Standard Reference Materials (SRMs) 1566 Oyster Tissue, 1567 Wheat Flour, 1568 Rice Flour, and 1570 Trace Elements in Spinach, produced by the National Institute of Standards and Technology (NIST, then the National Bureau of Standards), were analyzed 17–20 years after the original certification dates and 12–15 years after the certificates became invalid. Instrumental neutron activation analysis and thermal neutron prompt (γ-ray activation analysis were used to measure mass fractions for 27 elements in these SRMs to revalidate them for use in quality assurance (QA) programs required for food analysis programs within the U.S. Food and Drug Administration. With the exception of Se in SRM 1567, all element mass fractions were in agreement with certified values and literature data. Some evidence of B loss from SRM 1568 was observed. These materials were judged to be suitable for continued use in QA programs. Findings showed that these matrixes exhibited stability of moisture, mass fraction, and weight basis for far longer (≥15 years) than was indicated by the 5-year validity statement on the NIST Certificates of Analysis.
Testing Shelled Corn for Aflatoxin, Part III: Evaluating the Performance of Aflatoxin Sampling Plans
Authors: Johansson Anders S , Whitaker Thomas B , Giesbrecht Francis G , Hagler Winston M , Young James H
Published: February 2020

The effects of changes in sample size and/or sample acceptance level on the performance of aflatoxin sampling plans for shelled corn were investigated. Six sampling plans were evaluated for a range of sample sizes and sample acceptance levels. For a given sample size, decreasing the sample acceptance level decreases the percentage of lots accepted while increasing the percentage of lots rejected at all aflatoxin concentrations, and decreases the average aflatoxin concentration in lots accepted and lots rejected. For a given sample size where the sample acceptance level decreases relative to a fixed regulatory guideline, the number of false positives increases and the number of false negatives decreases. For a given sample size where the sample acceptance level increases relative to a fixed regulatory guideline, the number of false positives decreases and the number of false negatives increases. For a given sample acceptance level, increasing the sample size increases the percentage of lots accepted at concentrations below the regulatory guideline while increasing the percentage of lots rejected at concentrations above the regulatory guideline, and decreases the average aflatoxin concentration in the lots accepted while increasing the average aflatoxin concentration in the rejected lots. For a given sample acceptance level that equals the regulatory guideline, increasing the sample size decreases misclassification of lots, both false positives and false negatives.
Determination of Sodium Azide in Beverages by Ion Chromatography
Authors: Oshima Harumi , Ueno Eiji , Saito Isao , Matsumoto Hiroshi
Published: February 2020

A convenient method for determination of sodium azide in beverages using ion chromatography is described. This method combines the specificity for azide with a simple sample preparation using a bubble and trap apparatus that removes any interferences. Sodium azide in a sample was acidified, and the azide was converted to the volatile hydrazoic acid, which was trapped in 2.5mM sodium hydroxide solution. Determination was performed by isocratic ion chromatography using suppressed conductivity detection. Calibration curves were linear for 0.5 to 20 μg/mL sodium azide and the detection limit was 0.05 μg/mL. Recoveries of sodium azide from spiked samples (10.0 μg/g) were more than 82.6%. The method was then used to analyze various beverages.
Determination of Oxycodone Hydrochloride in Oral Solutions by High-Performance Thin-Layer Chromatography/Densitometry
Authors: Salomies Hannele E M , Salo Piia K
Published: February 2020

A thin-layer chromatography/densitometry method was developed and validated for the determination of oxycodone hydrochloride in oral solutions by using silica gel plates. A horizontal technique was used for development of the plates. The optimum composition for the mobile phase, which provided a suitable Rf value of 0.6 for oxycodone, was propanol–acetic acid–water–25% ammonia–methanol (20 + 1 + 1 + 3 + 10). Detection was at 234 nm. Oxycodone hydrochloride was stable on the sorbent and was precisely and accurately measured in the range of 0.3–1.5 μg/band.
Voltammetric Determination of Benazepril and Ramipril in Dosage Forms and Biological Fluids through Nitrosation
Authors: Belal Fathalla , Al-Zaagi Ibrahim A , Abounassif Mohamed A
Published: February 2020

A simple and highly sensitive voltammetric method was developed for the determination of benazepril (I) and ramipril (II). The compounds were treated with nitrous acid, and the cathodic current produced by the resulting nitroso derivatives was measured. The voltammetric behavior was studied by adopting direct current (DCt), differential pulse (DPP), and alternating current (ACt) polarography. Both compounds produced well-defined, diffusion-controlled cathodic waves over the whole pH range in Britton-Robinson buffers (BRb). At pH 3 and 5, the values of diffusion-current constants (Id), were 5.90 ± 0.40 and 6.66 ± 0.61 for I and II, respectively. The current–concentration plots for I were rectilinear over the range of 1.5–40 and 0.1–30 μg/mL in the DCt and DPP modes, respectively; for II, the range was 2–30 and 0.1–20 μg/mL in the DCt and DPP modes, respectively. The minimum detectabilities (S/N = 2) were 0.015 μg/mL (about 3.25 × 10−8M) and 0.012 μg/mL (about 2.88 × 10−8M) for I and II, respectively, adopting the DPP mode. Results obtained for the proposed method when applied to the determination of both compounds in dosage forms were in good agreement with those obtained using reference methods. Hydrochlorthiazide, which is frequently co-formulated with these drugs, did not interfere with the assay. The method was also applied to the determination of benazepril in spiked human urine and plasma. The percentage recoveries adopting the DPP mode were 96.2 ± 1.21 and 95.7 ± 1.61, respectively.
Automated Microwave Digestion of Certifiable Color Additives for Determination of Mercury by Cold Vapor Atomic Absorption Spectrometry
Authors: Hepp Nancy M , Cargill Anne M , Shields Wendy B
Published: February 2020

A procedure using an automated microwave flow digestion technique was developed and validated for the digestion of samples of certifiable color additives before mercury determination by cold vapor atomic absorption spectrometry. Recovery studies were performed by spiking most of the color additives subject to batch certification by the U.S. Food and Drug Administration with inorganic mercury (HgNO3) and with organic mercury (CH3HgCl). Successful recoveries of 72–113% Hg added at the 1 μg/g level were obtained. A method detection limit of 0.2μg Hg/g was estimated from a Hg-spiked FD&C Yellow No. 6 sample. At the specification level of 1 ppm Hg (1 μg Hg/g), the 95% confidence interval was ± 0.2 ppm (0.2 μg Hg/g).
Preconcentration of Bismuth(III) and Copper(II) by Solid-Phase Extraction and Subsequent Determination by Differential Pulse Polarography
Authors: Bhalotra Anju , Prui Bal Krishan
Published: February 2020

A differential pulse polarographic method is proposed for the trace determination of bismuth and copper from large volumes of aqueous samples after adsorption of their 1-(2-thiazolylazo)-2-naphthol complexes onto microcrystalline naphthalene in the pH ranges of 7.2–9.0 and 4.0–7.8, respectively. Bismuth and copper are desorbed from microcrystalline naphthalene with 9 mL 1M HCl. Well-defined peaks are obtained at Ep = −0.09 and −0.20 V versus a saturated calomel electrode, in an HCl–isoquinoline medium as the supporting electrolyte, for bismuth and copper, respectively. Bismuth is reduced reversibly with a 3-electron change, whereas copper is reduced irreversibly under these conditions. The detection limits are 55 ng/mL for bismuth and 91 ng/mL for copper. Linearity is maintained in the concentration ranges of 0.18–13.5 and 0.30-17.3 μg/mL for bismuth and copper, respectively, with corresponding correlation coefficients of 0.9996 and 0.9885. The relative standard deviations are 1.0% for bismuth at 2.0 μg/mL and 1.4% for copper at 5.0 μg/mL. Various parameters were optimized to develop conditions for the determination of these metal ions in various samples.