bluuebunny/crossref_metadata_2025 huggingface dataset:
Panel VAR models with interactive fixed effects
Authors: Tuğan Mustafa
Published: July 2020

In the literature, a common feature of panel models with interactive fixed effects is that they model a univariate variable. In this regard, they are incapable of addressing dynamic and simultaneous interactions among a set of macroeconomic variables, a problem that falls within the realm of structural analysis. This paper aims to contribute to the existing literature by studying a homogeneous panel vector autoregression (VAR) model with interactive fixed effects. The panel VAR model in question is flexible in that it can accommodate an arbitrary lag length and observable regressors that can be individual-specific or common. For factor VAR models with both a large cross-section (C) and a large time (T) dimension, we derive the limiting distribution of the interactive fixed estimator, allowing structural analysis to be extended to panel VAR models with interactive fixed effects.
Incremental value of left ventricular global longitudinal strain in a newly proposed staging classification based on cardiac damage in patients with severe aortic stenosis
Authors: Vollema E Mara , Amanullah Mohammed R , Prihadi Edgard A , Ng Arnold C T , van der Bijl Pieter , Sin Yoong Kong , Ajmone Marsan Nina , Ding Zee Pin , Généreux Philippe , Leon Martin B , Ewe See Hooi , Delgado Victoria , Bax Jeroen J
Published: July 2020

Aims

Cardiac damage in severe aortic stenosis (AS) can be classified according to a recently proposed staging classification. The present study investigated the incremental prognostic value of left ventricular (LV) global longitudinal strain (GLS) over stages of cardiac damage in patients with severe AS.

Methods and results

From an ongoing registry, a total of 616 severe symptomatic AS patients with available LV GLS by speckle tracking echocardiography were selected and retrospectively analysed. Patients were categorized according to cardiac damage on echocardiography: Stage 0 (no damage), Stage 1 (LV damage), Stage 2 (mitral valve or left atrial damage), Stage 3 (tricuspid valve or pulmonary artery vasculature damage), or Stage 4 (right ventricular damage). LV GLS was divided by quintiles and assigned to the different stages. The endpoint was all-cause mortality. Over a median follow-up of 44 [24–89] months, 234 (38%) patients died. LV GLS was associated with all-cause mortality independent of stage of cardiac damage. After incorporation of LV GLS by quintiles into the staging classification, Stages 2–4 were independently associated with outcome. LV GLS showed incremental prognostic value over clinical characteristics and stages of cardiac damage.

Conclusion

In this large single-centre cohort of severe AS patients, incorporation of LV GLS by quintiles in a novel proposed staging classification resulted in refinement of risk stratification by identifying patients with more advanced cardiac damage. LV GLS was shown to provide incremental prognostic value over the originally proposed staging classification.
Is IHL a Sham? A Reply to Eyal Benvenisti and Doreen Lustig
Authors: von Bernstorff Jochen
Published: July 2020

This contribution is inspired by the thought-provoking article ‘Monopolizing War’ by Eyal Benvenisti and Doreen Lustig. My Reply argues that early 19th-century IHL codification projects in the eyes of European governments did not primarily serve domestic anti-revolutionary purposes. It also takes a somewhat sceptical stance as to the recent scholarly trend, which reduces historical explanations for the development of international law to domestic contexts in one or more powerful states involved in the respective law- and policy-making process. Building on the intriguing historical critique of early IHL’s ‘humanizing substance’ developed in ‘Monopolizing War’ and by referring to more recent IHL codification projects (small arms, nuclear weapons, aerial bombing, autonomous weapons), the second part of the contribution sketches four ‘de-humanizing’ discursive strategies, which arguably haunt international humanitarian law-making until today: (i) cynical window dressing; (ii) constructing an ontological wall; (iii) utilitarian reasoning; and (iv) excluding the periphery.
COVID-19 is, in the end, an endothelial disease
Authors: Libby Peter , Lüscher Thomas
Published: July 2020

The vascular endothelium provides the crucial interface between the blood compartment and tissues, and displays a series of remarkable properties that normally maintain homeostasis. This tightly regulated palette of functions includes control of haemostasis, fibrinolysis, vasomotion, inflammation, oxidative stress, vascular permeability, and structure. While these functions participate in the moment-to-moment regulation of the circulation and coordinate many host defence mechanisms, they can also contribute to disease when their usually homeostatic and defensive functions over-reach and turn against the host. SARS-CoV-2, the aetiological agent of COVID-19, causes the current pandemic. It produces protean manifestations ranging from head to toe, wreaking seemingly indiscriminate havoc on multiple organ systems including the lungs, heart, brain, kidney, and vasculature. This essay explores the hypothesis that COVID-19, particularly in the later complicated stages, represents an endothelial disease. Cytokines, protein pro-inflammatory mediators, serve as key danger signals that shift endothelial functions from the homeostatic into the defensive mode. The endgame of COVID-19 usually involves a cytokine storm, a phlogistic phenomenon fed by well-understood positive feedback loops that govern cytokine production and overwhelm counter-regulatory mechanisms. The concept of COVID-19 as an endothelial disease provides a unifying pathophysiological picture of this raging infection, and also provides a framework for a rational treatment strategy at a time when we possess an indeed modest evidence base to guide our therapeutic attempts to confront this novel pandemic.
Differential effects of inotropes and inodilators on renal function in acute cardiac care
Authors: Zima Endre , Farmakis Dimitrios , Pollesello Piero , Parissis John T
Published: July 2020

Pathological interplay between the heart and kidneys is widely encountered in heart failure (HF) and is linked to worse prognosis and quality of life. Inotropes, along with diuretics and vasodilators, are a core medical response to HF but decompensated patients who need inotropic support often present with an acute worsening of renal function. The impact of inotropes on renal function is thus potentially an important influence on the choice of therapy. There is currently relatively little objective data available to guide the selection of inotrope therapy but recent direct observations on the effects of levosimendan and milrinone on glomerular filtration favour levosimendan. Other lines of evidence indicate that in acute decompensated HF levosimendan has an immediate renoprotective effect by increasing renal blood flow through preferential vasodilation of the renal afferent arterioles and increases in glomerular filtration rate: potential for renal medullary ischaemia is avoided by an offsetting increase in renal oxygen delivery. These indications of a putative reno-protective action of levosimendan support the view that this calcium-sensitizing inodilator may be preferable to dobutamine or other adrenergic inotropes in some settings by virtue of its renal effects. Additional large studies will be required, however, to clarify the renal effects of levosimendan in this and other relevant clinical situations, such as cardiac surgery.
Do interviewer attitudes to data linkage influence respondents’ consent to linkage? Analysis of Understanding Society
Authors: Patterson Lynsey , Cruise Sharon M , Cardwell Chris R , O’Reilly Dermot
Published: July 2020

Background

Variable consent rates threaten the validity of linked datasets. One modifiable element is the interviewer–respondent relationship. We examine interviewer attitudes to consent to linkage and the effect on respondent consent.

Methods

Subjects were 27 380 respondents from the Wave 1 Understanding Society (US) survey in Great Britain and 449 interviewers who completed the US Interviewer Survey. Two types of consent were considered: (i) whether the interviewer would hypothetically agree to having their data linked if he/she was an US respondent and (ii) whether the respondent consented to have their data linked. Factors influencing the interviewer’s propensity to link data were examined using logistic regression. The association between interviewer consent and respondent consent to health record linkage was assessed using multi-level logistic regression models.

Results

The interviewer’s propensity to consent to data linkage was strongly positively associated with its perceived usefulness: those that found it somewhat useful were 57% less likely to consent [adjusted odds ratio (AOR) 0.43, 95% CI: 0.22–0.82] compared to those who thought it was very useful. Positive beliefs about data security and their ability to understand the data linkage information were also associated. Respondents were 17% less likely to consent when interviewed by an interviewer who would not consent to record linkage (AOR 0.83, 95% CI: 0.71–0.97).

Conclusions

The interviewer’s propensity to consent was influenced by their beliefs about data linkage, which in turn influenced respondent consent. We recommend using interviewer training to emphasize the usefulness of data linkage and the measures around data security.
Willingness to pay for community delivery of antiretroviral treatment in urban Tanzania: a cross-sectional survey
Authors: Geldsetzer Pascal , Sauer Alexander , Francis Joel M , Mboggo Eric , Lwezaula Sharon , Sando David , Fawzi Wafaie , Ulenga Nzovu , Bärnighausen Till
Published: July 2020

Community health worker (CHW)-led community delivery of HIV antiretroviral therapy (ART) could increase ART coverage and decongest healthcare facilities. It is unknown how much patients would be willing to pay to receive ART at home and, thus, whether ART community delivery could be self-financing. Set in Dar es Salaam, this study aimed to determine patients’ willingness to pay (WTP) for CHW-led ART community delivery. We sampled ART patients living in the neighbourhoods surrounding each of 48 public-sector healthcare facilities in Dar es Salaam. We asked participants (N = 1799) whether they (1) preferred ART community delivery over standard facility-based care, (2) would be willing to pay for ART community delivery and (3) would be willing to pay each of an incrementally increasing range of prices for the service. 45.0% (810/1799; 95% CI: 42.7—47.3) of participants preferred ART community delivery over standard facility-based care and 51.5% (417/810; 95% CI: 48.1—55.0) of these respondents were willing to pay for ART community delivery. Among those willing to pay, the mean and median amount that participants were willing to pay for one ART community delivery that provides a 2-months’ supply of antiretroviral drugs was 3.61 purchasing-power-parity-adjusted dollars (PPP$) (95% CI: 2.96–4.26) and 1.27 PPP$ (IQR: 1.27–2.12), respectively. An important limitation of this study is that participants all resided in neighbourhoods within the catchment area of the healthcare facility at which they were interviewed and, thus, may incur less costs to attend standard facility-based ART care than other ART patients in Dar es Salaam. While there appears to be a substantial WTP, patient payments would only constitute a minority of the costs of implementing ART community delivery. Thus, major co-financing from governments or donors would likely be required.
IVF, from the past to the future: the inheritance of the Capri Workshop Group
Authors:   The Annual Capri Workshop Group, Albertini David F , Crosignani PierGiorgio , Dumoulin John , Evers Johannes L H , Leridon Henri , Mastenbroek Sebastiaan , Painter Rebecca , Pinborg Anja , Somigliana Edgardo , Baird David T , Glasier Anna , La Vecchia Carlo , Albertini David F , Crosignani PierGiorgio , Dumoulin John , Evers Johannes L H , Leridon Henri , Mastenbroek Sebastiaan , Painter Rebecca , Pinborg Anja , Somigliana Edgardo , Baird David T , Glasier Anna , La Vecchia Carlo
Published: July 2020

Today IVF use is booming all over the world and has even started to play a role in demographic analyses. Prognosis-adjusted estimates suggest that up to two-thirds of couples could achieve a live birth. However, the scenario is less exciting in reality. Discontinuation during the cycles is common, and age and ovarian response continue to be crucial in modulating this rate of success. A growing interest is now given to the risk of abuses and in particular to overtreatment and to prescriptions of useless, if not harmful, expensive additional treatments (‘add-ons’). A more rational, evidence-based and wise approach is needed. From a scientific perspective, several obscure aspects remain and warrant future investigations. Of particular interest are the neglected role of sperm selection, the potential adult implications of early embryo life in vitro and the issue of sustainability.
Risk of Postoperative Infectious Complications From Medical Therapies in Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis
Authors: Law Cindy C Y , Koh Deborah , Bao Yueyang , Jairath Vipul , Narula Neeraj
Published: July 2020

Objective

To assess the impact of inflammatory bowel disease (IBD) medications on postoperative infection risk within 30 days of surgery.

Methods

We searched multiple electronic databases and reference lists of articles dating up to August 2018 for prospective and retrospective studies comparing postoperative infection risk in patients treated with an IBD medication perioperatively with the risk in patients who were not taking that medication. Outcomes were overall infectious complications and intra-abdominal infections within 30 days of surgery.

Results

Sixty-three studies were included. Overall infectious complications were increased in patients who received anti–tumor necrosis factor (TNF) agents (odds ratio [OR] 1.26; 95% confidence interval [CI], 1.07-1.50) and corticosteroids (OR 1.34; 95% CI, 1.25-1.44) and decreased in those who received 5-aminosalicylic acid (OR 0.63; 95% CI, 0.46-0.87). No difference was observed in those treated with immunomodulators (OR 1.08; 95% CI, 0.94-1.25) or anti-integrin agents (OR 1.06; 95% CI, 0.67-1.69). Both corticosteroids and anti-TNF agents were associated with increased intra-abdominal infection risk (OR 1.63; 95% CI, 1.33-2.00 and OR 1.46; 95% CI, 1.08-1.97, respectively), whereas no impact was observed with 5-aminosalicylates, immunomodulators, or anti-integrin therapy. Twenty-two studies had low risk of bias while the remaining studies had very high risk.

Conclusions

Corticosteroids and anti-TNF agents were associated with increased overall postoperative infection risk as well as intra-abdominal infection in IBD patients, whereas no increased risk was observed for immunomodulators or anti-integrin therapy. Although these results may result from residual confounding rather than from a true biological effect, prospective studies that control for potential confounding factors are required to generate higher-quality evidence.
Variations in Health Care Utilization Patterns Among Inflammatory Bowel Disease Patients at Risk for High Medical Service Utilization Enrolled in High Deductible Health Plans
Authors: Berinstein Jeffrey A , Cohen-Mekelburg Shirley A , Steiner Calen A , McLeod Megan , Noureldin Mohamed , Allen John I , Kullgren Jeffrey T , Waljee Akbar K , Higgins Peter D R
Published: July 2020

Background

High-deductible health plans (HDHPs) are increasing in prevalence as a cost control device for slowing health care cost growth by reducing nonessential medical service utilization. High cost-sharing associated with HDHPs can lead to significant financial distress and worse disease outcomes. We hypothesize that chronic disease patients are delaying or foregoing necessary medical care due to health care costs.

Methods

A retrospective cohort analysis of IBD patients at risk for high medical service utilization with continuous enrollment in either an HDHP or THP from 2009 to 2016 were identified using the MarketScan database. Health care costs were compared between insurance plan groups by Kruskal-Wallis test. Temporal trends in office visits, colonoscopies, emergency department (ED) visits, and hospitalizations were evaluated using additive decomposition time series analysis.

Results

Of 605,862 patients with a diagnosis of IBD, we identified 13,052 eligible patients. Annual out-of-pocket costs were higher in the HDHP group (n = 524) than the THP group (n = 12,458) ($2870 vs $1,864; P < 0.001) without any difference in total health care expenses ($23,029 vs $23,794; P = 0.583). Enrollment in an HDHP influenced colonoscopy, ED visit, and hospitalization utilization timing. Colonoscopies peaked in the fourth quarter, ED visits peaked in the first quarter, and hospitalizations peaked in the third and fourth quarter.

Conclusions

High-deductible health plan enrollment does not change the cost of care; however, it shifts health care costs onto patients and changes the timing of the care they receive. High-deductible health plans are incentivizing delays in obtaining health care with a potential to cause worse disease outcomes and financial distress. Further evaluation is warranted.
How storms affect fishers’ decisions about going to sea
Authors: Pfeiffer Lisa
Published: July 2020

Fishermen are known to try to avoid fishing in stormy weather, as storms pose a physical threat to fishers, their vessels, and their gear. In this article, a dataset and methods are developed to investigate the degree to which fishers avoid storms, estimate storm aversion parameters, and explore how this response varies across vessel characteristics and across regions of the United States. The data consist of vessel-level trip-taking decisions from six federal fisheries across the United States combined with marine storm warning data from the National Weather Service. The estimates of storm aversion can be used to parameterize predictive models. Fishers’ aversion to storms decreases with increasing vessel size and increases with the severity of the storm warning. This information contributes to our understanding of the risk-to-revenue trade-off that fishers evaluate every time they consider going to sea, and of the propensity of fishers to take adaptive actions to avoid facing additional physical risk.
Respiratory Syncytial Virus and All-Cause Bronchiolitis Hospitalizations Among Preterm Infants Using the Pediatric Health Information System (PHIS)
Authors: Fergie Jaime , Suh Mina , Jiang Xiaohui , Fryzek Jon P , Gonzales Tara
Published: July 2020

Background

In 2014, the American Academy of Pediatrics stopped recommending palivizumab to otherwise healthy 29–34 weeks’ gestational age (wGA) infants aged <12 months at respiratory syncytial virus (RSV) season start. Here, we compare the burden of RSV hospitalizations (RSVH) and all-cause bronchiolitis hospitalizations (BH) before and after 2014 among otherwise healthy 29–34 wGA infants hospitalized at ≤6 months of age.

Methods

A historical, observational cohort study was conducted to evaluate RSVH and BH in 29–34 wGA infants during the 2010–2017 RSV seasons using encounter data from 51 United States children’s hospitals that comprise the Pediatric Health Information System.

Results

The overall cohort included 67 570 RSVH out of 96 281 patients with BH. wGA was known for 22 937 RSVH and 33 289 BH. For 29–34 wGA infants, there were 8.7% and 14.2% RSVH before and after 2014, respectively (P < .0001). Intensive care unit admissions increased for RSVH (from 54.5% to 64.2%; P = .0002) and BH (from 46.7% to 54.5%; P = .0005) after controlling for sex, race, comorbidity, and cluster. The total cost of care increased for RSVH from $37 million to nearly $60 million.

Conclusions

RSVH, BH, and their severity increased among 29–34 wGA infants in the 3 RSV seasons following 2014.
Environmental Sampling for Severe Acute Respiratory Syndrome Coronavirus 2 During a COVID-19 Outbreak on the Diamond Princess Cruise Ship
Authors: Yamagishi Takuya , Ohnishi Makoto , Matsunaga Nobuaki , Kakimoto Kensaku , Kamiya Hajime , Okamoto Kiyoko , Suzuki Motoi , Gu Yoshiaki , Sakaguchi Mikiyo , Tajima Taichi , Takaya Saho , Ohmagari Norio , Takeda Makoto , Matsuyama Shuyoku , Shirato Kazuya , Nao Naganori , Hasegawa Hideki , Kageyama Tsutomu , Takayama Ikuyo , Saito Shinji , Wada Koji , Fujita Retsu , Saito Hiroki , Okinaka Keiji , Griffith Mathew , Parry Amy Elizabeth , Barnetson Brenda , Leonard James , Wakita Takaji
Published: July 2020

During a COVID-19 outbreak on the Diamond Princess cruise ship we sampled environmental surfaces after passengers and crew vacated cabins. SARS-CoV-2 RNA was detected in 58 of 601 samples (10%) from case cabins 1–17 days after cabins were vacated but not from noncase cabins. There was no difference in detection proportion between cabins of symptomatic (15%, 28/189; cycle quantification [Cq], 29.79–38.86) and asymptomatic cases (21%, 28/131; Cq, 26.21–38.99). No SARS-CoV-2 virus was isolated from any of the samples. Transmission risk of SARS-CoV-2 from symptomatic and asymptomatic patients may be similar and surfaces could be involved in transmission.
Continued In-Hospital Angiotensin-Converting Enzyme Inhibitor and Angiotensin II Receptor Blocker Use in Hypertensive COVID-19 Patients Is Associated With Positive Clinical Outcome
Authors: Lam Katherine W , Chow Kenneth W , Vo Jonathan , Hou Wei , Li Haifang , Richman Paul S , Mallipattu Sandeep K , Skopicki Hal A , Singer Adam J , Duong Tim Q
Published: July 2020

Background

This study investigated continued and discontinued use of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin II receptor blockers (ARB) during hospitalization of 614 hypertensive laboratory-confirmed COVID-19 patients.

Methods

Demographics, comorbidities, vital signs, laboratory data, and ACEi/ARB usage were analyzed. To account for confounders, patients were substratified by whether they developed hypotension and acute kidney injury (AKI) during the index hospitalization.

Results

Mortality (22% vs 17%, P > .05) and intensive care unit (ICU) admission (26% vs 12%, P > .05) rates were not significantly different between non-ACEi/ARB and ACEi/ARB groups. However, patients who continued ACEi/ARBs in the hospital had a markedly lower ICU admission rate (12% vs 26%; P = .001; odds ratio [OR] = 0.347; 95% confidence interval [CI], .187–.643) and mortality rate (6% vs 28%; P = .001; OR = 0.215; 95% CI, .101–.455) compared to patients who discontinued ACEi/ARB. The odds ratio for mortality remained significantly lower after accounting for development of hypotension or AKI.

Conclusions

These findings suggest that continued ACEi/ARB use in hypertensive COVID-19 patients yields better clinical outcomes.
Determination of Oligofructose, a Soluble Dietary Fiber, by High-Temperature Capillary Gas Chromatography
Authors: Joye Dirk , Hoebregs Hubert
Published: July 2020

A high-temperature capillary gas chromatographic method was developed for the quantitative determination of oligofructose in foods and food products. Sample preparation involves oxymation and silylation of the extracted sugars. The oximetrimethylsilyl derivatives are analyzed on an apolar capillary column, with detection by flame ionization. The method is accurate, with recovery of spiked samples at >96%. Repeatability was excellent; RSD values of 1.1% were obtained. Other common oligosaccharides, such as malto-, isomalto-, and galactooligosaccharides, and levan do not interfere, making the method specific and reliable.
Determination of Volatile Bases in Seafood Using the Ammonia Ion Selective Electrode: Collaborative Study
Authors: Ellis P Christopher , Pivarnik Lori F , Thiam Mamadou ,   Collaborators:, Berger L , Field S , Green D , Hewes D , Lemerise D , Lyttle C , Maciel J , Soper K
Published: July 2020

Nine collaborating laboratories tested a combination of 23 seafood samples for volatile bases using an ammonia ion selective electrode. Results were reported as mg NH3/100 g fish, but the method reflected levels of both ammonia and trimethylamine, which permeated the ammonia membrane. The 23 samples were broken down into 8 blind duplicate pairs, 2 Youden matched pairs, and 3 single samples covering fresh to spoiled product ranging from 8 to 82 mg NH3/100 g. Seven species were evaluated: Atlantic cod, squid, Atlantic halibut, gray sole, monkfish, dogfish, and Atlantic mackerel. The ammonia electrode assay was performed on an aqueous homogenate consisting of 95 mL distilled water and 5.0 g sample tissue. Alkaline ion strength adjusting solution (2 mL) was added to the homogenate to liberate ammonia that was sensed by the ion specific electrode and measured on a precalibrated portable meter. Repeatability standard deviations (RSDr) ranged from 4.2 to 17%; reproducibility standard deviations (RSDR) ranged from 8.8 to 21%. A standard ammonium chloride solution was provided to all laboratories to spike 3 different samples at 10 mg NH3/100 g. Recoveries of added ammonia as ammonium chloride for fresh, borderline, and spoiled samples were 88.6, 107, and 128%, respectively.
Improved Diffusion Methods for Nitrogen and 15Nitrogen Analysis of Kjeldahl Digests
Authors: Stevens W Bart , Mulvaney Richard L , Khan Saeed A , Hoeft Robert G
Published: July 2020

Simple methods are described that permit the use of either H3BO3 indicator solution or acidified filter disks to collect NH3 liberated by treatment of Kjeldahl digests with NaOH. These methods incorporate modifications to improve reliability, analytical capacity, and convenience. A semimicro digest was diluted to 25 mL with deionized water, and a 10 mL aliquot, containing up to 4 mg N (150 μg N for diffusions into acidified disks), was transferred to a shell vial, which was placed inside a 473 mL (1 pint) Mason jar containing 10 mL 10N NaOH. The NH3 liberated by overturning the vial was collected after 12 to 48 h at ambient temperature, or after 4 h at 45 to 50°C on a hotplate, for quantitative and/or isotope-ratio analyses. With either H3BO3 indicator solution or acidified filter disks, recovery of diffused N was quantitative. Isotope-ratio analyses of diffused N from 15N-labeled chemical, plant, and soil samples were within 3% of analyses using steam distillation.
Liquid Chromatographic Method with Electrochemical Detection for Determination of Cisapride in Serum
Authors: De Condado Maria C , Malave Andres , Dorantes-Hernandez Miguel A , Rathinavelu Appu
Published: July 2020

A sensitive liquid chromatographic (LC) method using electrochemical detection was developed for the identification and quantitation of cisapride in serum. The serum samples were deproteinized by a simple acetonitrile precipitation technique followed by n-hexane extraction. Cisapride in the deproteinized serum was separated by an isocratic elution with an ODS Hypersil LC column (150 × 4.6 mm) using a mobile phase consisting of 0.05M Na2HPO4–acetonitrile (60 + 40), pH 8.4. Cisapride eluted from the column was detected by a Coulochem II electrochemical detector. The precision of this assay method was determined by intra- and inter-day analyses of cisapride-free fetal bovine serum samples that were spiked with 25, 50, and 100 ng/mL cisapride. For the intra-day assay, recoveries were 94.3 ± 1.4, 90.1 ± 2.9, and 103.2 ± 9.2%, respectively. This electrochemical detection LC method could be very useful in monitoring plasma levels of cisapride.
Identification of Nile Perch (Lates niloticus), Grouper (Epinephelus guaza), and Wreck Fish (Polyprion americanus) Fillets by PCR Amplification of the 5S rDNA Gene
Authors: Asensio Luis , González Isabel , Fernández Alicia , Céspedes Ana , Rodríguez Miguel A , Hernández Pablo E , García Teresa
Published: July 2020

Nile perch (Lates niloticus), grouper (Epinephelus guaza), and wreck fish (Polyprion americanus) were differentiated by polymerase chain reaction (PCR) amplification of the nuclear 5S rDNA gene. The design of 3 species-specific primers complementary to the nontranscribed intergenic spacer region from the 5S rDNA molecule allowed amplification of clearly distinguishable gene fragments in each fish species. This approach is rapid and reliable and offers the potential to detect fraudulent or unintentional mislabeling of these species in routine seafood authentication analysis.
Certified Reference Material for Analytical Quality Assurance of Minor and Trace Elements in Food and Related Matrixes Based on a Typical Japanese Diet: Interlaboratory Study
Authors: Yoshinaga Jun , Morita Masatoshi , Yukawa Masae , Shiraishi Kunio , Kawamura Hisao ,   Collaborators:, Arae H , Baker S , Barnes R M , Dang H S , De Regge P , Funato Y , Futatsugawa K , Hirai S , Kato T , Kawamoto K , Matsubara M , Matsue H , Miller-Ihli N J , Muramatsu Y , Narukawa T , Okada Y , Reitznerová E , Sakamoto H , Sera K , Shindo K , Suzuki S , Takata J , Takeuchi T , Tamari Y , Tanizaki Y , Veillon C , Yasui A , Yonezawa C
Published: July 2020

A Certified Reference Material (CRM) was prepared at the National Institute for Environmental Studies (NIES), Japan, in collaboration with the National Institute of Radiological Sciences (NIRS), Japan, for the analytical quality assurance of minor and trace elements in food and related matrixes. The starting material for the CRM was all food served in 29 households in Japan over two 3-day periods in 1997–1998, and thus the CRM represented a typical Japanese diet. All foods (meals, snacks, and beverages) were homogenized, freeze-dried, pulverized, blended, dispensed into 1100 bottles, and sterilized. The within- and between-bottle homogeneity of the prepared CRM was satisfactory for most of the elements. The concentrations of 14 elements (Na, Mg, K, Ca, Mn, Cu, Zn, As, Se, Sr, Cd, Sn, Ba, and U) were certified based on a collaborative analysis involving NIES, NIRS, and 20 other laboratories. Reference values were given for the concentrations of 12 additional elements (P, Cl, Fe, Co, Ni, Br, Rb, Mo, I, Cs, Pb, and Th). The elements certified and those given reference values include minerals, essential trace elements, contaminant elements, and long-lived radionuclides. Thus, this CRM is of practical value in the quality assurance of element analysis of foods and diets in nutritional, environmental, and radiological research.
Improved Method for Determination of Abamectin and Ivermectin in Cattle Plasma
Authors: Wei Guang Zhi , Li Jun Suo
Published: July 2020

A liquid chromatographic (LC) method was developed for determination of abamectin (ABM) and ivermectin (IVM) in cattle plasma. The sample was extracted with acetonitrile and cleaned up on an alumina column. After conversion to stable fluorescent derivative with trifluoroacetic anhydride and N-methylimidazole, the sample was analyzed by LC with fluorescence detection (Ex 365 nm and Em 475 nm). Doramectin was used as an internal standard. Recoveries ranged from 91.2 to 100.7% for IVM and from 87.0 to 98.7% for ABM, with 1–50 ng/mL fortified samples. The coefficients of variation were <10.1%. The limit of detection was 0.02 ng/mL for ABM and IVM in 1.0 mL samples.
Determination of Organochlorinated Compounds in Marine Organisms by Microwave-Assisted Extraction with Molecular Organized Systems and Liquid Chromatography with Fluorescence Detection
Authors: Sanz Carolina Padrón , Fernández Arantza Eiguren , Ferrera Zoraida Sosa , Rodríguez Jose Juan Santana
Published: July 2020

Microwave-assisted extraction methodology is used to extract different compounds from various kinds of marine solid samples, such as soils, sediments, and organisms. A new analytical method was developed to extract polychlorinated biphenyls and polychlorinated dibenzofurans by using a conventional microwave system and the nonionic surfactant, polyoxyethylene 10 lauryl ether as the extractant as a prior step to liquid chromatography analysis coupled with fluorescence detection. The method was applied to the extraction and determination of these analytes in samples of blue mussels (Mytilus galloprovincialis), cockles (Cerastoderma edule), and clams (Dosinia exoleta). Compared with the traditional Soxhlet extraction, results of the proposed method showed acceptable recovery percentages for the organochlorinated compounds under study and standard deviation values <10%.
Multiresidue Determination of Pesticides in Drinking and Related Waters by Solid-Phase Extraction and Liquid Chromatography with Ultraviolet Detection: Interlaboratory Study
Authors: Hoof François van , Wiele Peter van , Acobas Françoise , Guinamant Jean-Luc , Bruchet Auguste , Schmitz Isabelle , Bobeldijk Ivana , Sacher Frank , Ventura Francesc ,   Collaborators:, Alterova K , Barcelo D , Barnier A , De Buyzer C , Mérard G , Hajslova J , Marti I , Martinez K , Planas C , Pussemier L , Rivera J , Oörden R , Tejedor A , van der Kreeft R , Vanermen G , Walravens E , Werres F , Wouters E
Published: July 2020

As part of a project funded by the European Commission (EC) for the development and evaluation of multiresidue methods for analysis of drinking and related waters, 17 European laboratories evaluated a method using styrene–divinylbenzene copolymer solid-phase extraction followed by liquid chromatography with diode array detection. The main aim of the study was to evaluate whether the method meets the requirements of EC Drinking Water Directive 98/83 in terms of accuracy, precision, and detection limit for 21 pesticides according to the following requirements: limit of detection, ≤0.025 μg/L; accuracy expressed as recovery, between 75 and 125%; and precision expressed as repeatability relative standard deviation of the method, <12.5%, and as reproducibility relative standard deviation of the method, <25%. Analyses for unknown concentrations were performed with commercial bottled and tap waters. All laboratories were able to achieve detection limits of 0.01 μg/L for all pesticides except pirimicarb (0.02 μg/L). The criteria for repeatability were met for all compounds. Terbutryn in bottled water and carbendazim in tap water did not meet the criteria for reproducibility. In terms of accuracy, the method met the requirements for all pesticides in both matrixes, except for metamitron. However, several compounds (linuron, terbutryn, propazine, metobromuron, and isoproturon) showed recoveries slightly below 75%.
Interlaboratory Comparison of Methods for the Determination of Incurred Tilmicosin Residues in Bovine Liver
Authors: Clark Susan B , O'rangers John J , Rowe W Douglas , Madson Mark R , Hurlbut Jeffrey A , Sofos John N , Fuerst Brenda , James Glenda , Griffith Sydney , Readnour Robin S
Published: July 2020

The objective of this study was to compare 2 methods for the determination of tilmicosin residues in bovine liver samples. Three laboratories participated in the comparison of the 2 methods. The first method was described in a New Animal Drug Application (NADA 140–929), and the second was a modification of that method in which hexane was substituted for carbon tetrachloride in one cleanup step. Each of the 3 laboratories analyzed subsamples of 10 bovine livers containing incurred tilmicosin. Residues ranged from 2.3 to 81 ppm tilmicosin in the 10 liver samples with an 11.8% relative standard deviation obtained by using both methods. In addition, fortified-control liver tissue samples were analyzed concurrently with tissues containing incurred residues by using the modified method in one of the laboratories. The fortification levels ranged from 0.3 to 112 ppm, with recoveries ranging from 76 to 92%. The results from the 3 laboratories were comparable, indicating that the modified method was not only as effective as the original NADA method, but also more desirable because of the change to a less hazardous solvent.
A Gas Chromatographic Determination of Residues of Eleven Insecticides and Two Metabolites on Olive Tree Leaves
Authors: Aplada-Sarlis Pipina , Miliadis George E , Liapis Konstantinos , Tsiropoulos Nicholas G
Published: July 2020

A gas chromatographic (GC) method was developed and statistically validated for the simultaneous determination of residues of pyrethroid, endosulfan, and organophosphorus insecticides and some of their metabolites on olive tree leaves. Pesticide residues were extracted by static extraction with acetone–dichloromethane. After evaporation of the extract to dryness and redissolution in acetone, the organophosphorus insecticides were determined by GC with nitrogen–phosphorus detection. Another portion of the extract, after solvent change to acetonitrile, was cleaned up on an Alumina-N cartridge and analyzed for insecticides sensitive to electron-capture detection (ECD), i.e., pyrethroids and endosulfan and its metabolite. Recoveries of the organophosphorus insecticides ranged from 80.7 to 93.3% with relative standard deviations (RSDs) of ≤ 7.2%; recoveries of the ECD-sensitive insecticides ranged from 71.6 to 89.5% with RSDs of ≤ 11.6%. The method was used to analyze 26 samples of olive tree leaves from organic olive groves all over Greece, and the results confirmed the viability of the method for routine analysis. Residues of fenthion and fenthion sulfoxide were found in one and 3 samples, respectively, and their identities were confirmed by GC with mass spectrometry.
Total Arsenic Determination and Speciation in Infant Food Products by Ion Chromatography-Inductively Coupled Plasma-Mass Spectrometry
Authors: Vela Nohora P , Heitkemper Douglas T
Published: July 2020

Health risk associated with dietary arsenic intake may be different for infants and adults. Seafood is the main contributor to arsenic intake for adults while terrestrial-based food is the primary source for infants. Processed infant food products such as rice-based cereals, mixed rice/formula cereals, milk-based infant formula, applesauce and purée of peaches, pears, carrots, sweet potatoes, green beans, and squash were evaluated for total and speciated arsenic content. Arsenic concentrations found in rice-based cereals (63–320 ng/g dry weight) were similar to those reported for raw rice. Results for the analysis of powdered infant formula by inductively coupled plasma-mass spectrometry (ICP-MS) indicated a narrow and low arsenic concentration range (12 to 17 ng/g). Arsenic content in purée infant food products, including rice cereals, fruits, and vegetables, varies from <1 to 24 ng/g wet weight. Sample treatment with trifluoroacetic acid at 100°C were an efficient and mild method for extraction of arsenic species present in different food matrixes as compared to alternative methods that included sonication and accelerated solvent extraction. Extraction recoveries from 94 to 128% were obtained when the summation of species was compared to total arsenic. The ion chromatography (IC)-ICP-MS method selected for arsenic speciation allowed for the quantitative determination of inorganic arsenic [As(III) + As(V)], dimethylarsinic acid (DMA), and methylarsonic acid (MMA). Inorganic arsenic and DMA are the main species found in rice-based and mixed rice/formula cereals, although traces of MMA were also detected. Inorganic arsenic was present in freeze-dried sweet potatoes, carrots, green beans, and peaches. MMA and DMA were not detected in these samples. Arsenic species in squash, pears, and applesauce were not detected above the method detection limit [5 ng/g dry weight for As(III), MMA, and DMA and 10 ng/g dry weight for As(V)].
Evaluation of the BAX® System for Detection of Listeria monocytogenes in Foods: Collaborative Study
Authors: Silbernagel Karen , Jechorek Robert , Barbour W Mark , Mrozinski Peter ,   Collaborators:, Alejo W , Aleo V , Andaloro B , Beacorn F , Benzinger J , Bogar S , Brayman C , Broom J , Carson M , Carver C , Cheng C , Centrella B , Clayborn J , Collins C , Deibel C , Divine M , Eliasberg S , Farmer D , Frye S , Gatesy T , Goodstein E , Halker C , Hall G , Hanson P , Hartman G , Heddaeus K , Hembree J , Hutchins J , Istafanos P , Jechorek R , Jenkins J , Kerdahi K , Kremer S , Lal A , Leighton S , Lester D , Lewis J , Lin J , Martin J , Maselli M , McCarthy P , McGovern B , Mills M , Mohnke F , Moon B , Moss D , Plaza M , Robeson S , Romero H , Rubalcaba D , Schultz A , Seehusen J , Shaw C , Siem K , Sloan E , Stanerson J , Stepanova N , Van K , Van Enkenvoort K , Vialpando M , Warren W , Watts K , Wilson K , Woodruff T
Published: July 2020

A multilaboratory study was conducted to compare the automated BAX® system and the standard cultural methods for detection of Listeria monocytogenes in foods. Six food types (frankfurters, soft cheese, smoked salmon, raw, ground beef, fresh radishes, and frozen peas) were analyzed by each method. For each food type, 3 inoculation levels were tested: high (average of 2 CFU/g), low (average of 0.2 CFU/g) and uninoculated controls. A total of 25 laboratories representing government and industry participated. Of the 2335 samples analyzed, 1109 were positive by the BAX system and 1115 were positive by the standard method. A Chi square analysis of each of the 6 food types, at the 3 inoculation levels tested, was performed. For all foods, except radishes, the BAX system performed as well as or better than the standard reference methods based on the Chi square results.
Optimization of Solid-Phase Microextraction for the Gas Chromatography/Mass Spectrometry Analysis of Persistent Organic Pollutants
Authors: Gago-Martínez Ana , Nogueiras María J , Rellán Sandra , Prado Juan , Alpendurada María F , Vetter Walter
Published: July 2020

In this work, solid-phase microextraction (SPME) has been applied as an alternative for the selective extraction of 3 polybrominated diphenyl ethers (PBDEs), 2,2′,4,4′-tetrabromodiphenyl ether (PBDE-47); 2,2′,4,4′,5-pentabromodiphenyl ether (PBDE-99); and 2,2′,4,4′,6-pentabromodiphenyl ether (PBDE-100), and 2 alkylphenols, 4-tert-OP and 4-NP, prior to their analysis by gas chromatography/mass spectrometry (GC/MS). The advantages of this technique are mainly its simplicity, cost-effectiveness, and time-saving sample preparation, as well as being a solvent-free technique. With the aim of optimizing the conditions for an efficient extraction of the studied compounds, different fiber coatings and the main parameters affecting the extraction procedure have been evaluated. The results obtained showed a good linearity in the range of concentrations investigated, and adequate relative standard deviation values were found according to the range accepted for SPME. Recovery values were in the range of 78–108%, and good detection and quantitation limits at ppt levels were obtained for both methods, allowing the determination of the selected compounds in samples at trace levels. The results obtained clearly show the potential of SPME for efficient concentration of the target compounds and also demonstrate the reliability of this extraction technique for their GC/MS analysis.
Evaluation of VIDAS Listeria monocytogenes II (LMO2) Immunoassay Method for the Detection of Listeria monocytogenes in Foods: Collaborative Study
Authors: Silbernagel Karen M , Carver Charles N , Jechorek Robert P , Johnson Ronald L ,   Collaborators:, Alejo W , Aleo V , Buresh J , Cagri A , Campbell S , Carson M , Chinault K , Clayborn J , Cook F , Dammann H , Dorn S , Elko B , Farmer D , Farmer R , Gasses T , Greiman L , Guzman C , Hemker M , Hintz C , Jechorek R , Jenkins J , Kexel N , Kildisg J , Knickerbocker J , Kora L , Koziczkowski J , Krieg D , Lal A , Lam L , Lau D , Loftis M , Madewell L , Matisko V , Miele A , Muzzy T , Park J , Peters C , Pickett J , Radermacher S , Romero H , Ross J , Rotten J , Rule P , Ryser E , Satterwhite L K , Schultz A , Shell D , Smith J , Storment E , Ulmer M , Walia J , Whetzel S , Woltman N
Published: July 2020

A multilaboratory study was conducted to compare the VIDAS®Listeria monocytogenes II (LMO2) immunoassay and the standard cultural methods for the detection of Listeria monocytogenes in foods. Five food types—vanilla ice cream, brie cheese, cooked roast beef, frozen green beans, and frozen tilapia fish—at 3 levels were analyzed by each method. A total of 26 laboratories representing government and industry participated. In this study, 1404 test portions were analyzed of which 1152 were used in the statistical analysis. There were 448 positive by the VIDAS LMO2 assay and 457 positive by the standard culture methods. A χ2 analysis of each of the 5 food types, at the 3 inoculation levels tested, was performed. The resulting χ2 value, 0.36, indicates that overall, there are no statistical differences between the VIDAS LMO2 assay and the standard methods at the 5% level of significance.
A Multiresidue Pesticide Monitoring Procedure Using Gas Chromatography/Mass Spectrometry and Selected Ion Monitoring for the Determination of Pesticides Containing Nitrogen, Sulfur, and/or Oxygen in Fruits and Vegetables
Authors: Mercer Gregory E , Hurlbut Jeffrey A
Published: July 2020

A procedure for the analysis of over 100 pesticides that only contain combinations of carbon, hydrogen, nitrogen, sulfur, and oxygen (i.e., no phosphorous or halogen atoms) has been developed. The procedure employs gas chromatography with a mass selective detector (GC/MSD), electron impact ionization, and selected ion monitoring. This GC/MSD procedure provided lower limits of quantitation and increased confirmational data compared to the traditional element-selective GC procedures that are commonly used for the detection of this “class” of pesticides. These analytical improvements were demonstrated by 26 pesticides that were detected at ng/g levels in a variety of fruit and vegetable matrixes using this procedure; these pesticides were missed by the traditional element-selective GC procedures. Validation of the procedure was performed using acetone extraction with solid-phase extraction cleanup. Twenty representative target pesticides were used to demonstrate repeatability and linearity of the chromatographic response and recovery from fruit and vegetable matrixes.
A Square-Wave Adsorptive Stripping Voltammetric Method for the Determination of Amaranth, a Food Additive Dye
Authors: Alghamdi Ahmad H
Published: July 2020

Square-wave adsorptive stripping voltammetric (AdSV) determinations of trace concentrations of the azo coloring agent Amaranth are described. The analytical methodology used was based on the adsorptive preconcentration of the dye on the hanging mercury drop electrode, followed by initiation of a negative sweep. In a pH 10 carbonate supporting electrolyte, Amaranth gave a well-defined and sensitive AdSV peak at −518 mV. The electroanalytical determination of this azo dye was found to be optimal in carbonate buffer (pH 10) under the following experimental conditions: accumulation time, 120 s; accumulation potential, 0.0 V; scan rate, 600 mV/s; pulse amplitude, 90 mV; and frequency, 50 Hz. Under these optimized conditions the AdSV peak current was proportional over the concentration range 1 × 10−8 − 1.1 × 10−7 mol/L (r = 0.999) with a detection limit of 1.7 × 10−9 mol/L (1.03 ppb). This analytical approach possessed enhanced sensitivity, compared with conventional liquid chromatography or spectrophotometry and it was simple and fast. The precision of the method, expressed as the relative standard deviation, was 0.23%, whereas the accuracy, expressed as the mean recovery, was 104%. Possible interferences by several substances usually present as food additive azo dyes (E110, E102), gelatin, natural and artificial sweeteners, preservatives, and antioxidants were also investigated. The developed electroanalyticals method was applied to the determination of Amaranth in soft drink samples, and the results were compared with those obtained by a reference spectrophotometric method. Statistical analysis (paired t-test) of these data showed that the results of the 2 methods compared favorably.