bluuebunny/crossref_metadata_2025 huggingface dataset:
Small extracellular vesicles deliver miR‐21 and miR‐217 as pro‐senescence effectors to endothelial cells
Authors: Mensà Emanuela , Guescini Michele , Giuliani Angelica , Bacalini Maria Giulia , Ramini Deborah , Corleone Giacomo , Ferracin Manuela , Fulgenzi Gianluca , Graciotti Laura , Prattichizzo Francesco , Sorci Leonardo , Battistelli Michela , Monsurrò Vladia , Bonfigli Anna Rita , Cardelli Maurizio , Recchioni Rina , Marcheselli Fiorella , Latini Silvia , Maggio Serena , Fanelli Mirco , Amatori Stefano , Storci Gianluca , Ceriello Antonio , Stocchi Vilberto , De Luca Maria , Magnani Luca , Rippo Maria Rita , Procopio Antonio Domenico , Sala Claudia , Budimir Iva , Bassi Cristian , Negrini Massimo , Garagnani Paolo , Franceschi Claudio , Sabbatinelli Jacopo , Bonafè Massimiliano , Olivieri Fabiola
Published: February 2020

The role of epigenetics in endothelial cell senescence is a cutting‐edge topic in ageing research. However, little is known of the relative contribution to pro‐senescence signal propagation provided by microRNAs shuttled by extracellular vesicles (EVs) released from senescent cells. Analysis of microRNA and DNA methylation profiles in non‐senescent (control) and senescent (SEN) human umbilical vein endothelial cells (HUVECs), and microRNA profiling of their cognate small EVs (sEVs) and large EVs demonstrated that SEN cells released a significantly greater sEV number than control cells. sEVs were enriched in miR‐21‐5p and miR‐217, which target DNMT1 and SIRT1. Treatment of control cells with SEN sEVs induced a miR‐21/miR‐217‐related impairment of DNMT1‐SIRT1 expression, the reduction of proliferation markers, the acquisition of a senescent phenotype and a partial demethylation of the locus encoding for miR‐21. MicroRNA profiling of sEVs from plasma of healthy subjects aged 40–100 years showed an inverse U‐shaped age‐related trend for miR‐21‐5p, consistent with senescence‐associated biomarker profiles. Our findings suggest that miR‐21‐5p/miR‐217 carried by SEN sEVs spread pro‐senescence signals, affecting DNA methylation and cell replication.
Nearly golden-ratio order in Ta metallic glass*
Authors: Jiang Yuan-Qi , Peng Ping
Published: February 2020

The formation of mono-atomic tantalum (Ta) metallic glass (MG) through ultrafast liquid cooling is investigated by ab-initio molecular dynamics (MD) simulations. It is found that there exists nearly golden ratio order (NGRO) between the nearest and second nearest atoms in Ta MG, which has been indirectly confirmed by Khmich et al. and Liang et al.. The NGRO is another universal structural feature in metallic glass besides the local five-fold symmetry (LFFS). Further analyzing of electronic structure shows that the obvious orientation of covalent bond could be attributed to the NGRO in amorphous Ta at 300 K.
Network correlation between investor’s herding behavior and overconfidence behavior*
Authors: Zhang Mao , Wang Yi-Ming
Published: February 2020

It is generally accepted that herding behavior and overconfidence behavior are unrelated or even mutually exclusive. However, these behaviors can both lead to some similar market anomalies, such as excessive trading volume and volatility in the stock market. Due to the limitation of traditional time series analysis, we try to study whether there exists network relevance between the investor’s herding behavior and overconfidence behavior based on the complex network method. Since the investor’s herding behavior is based on market trends and overconfidence behavior is based on past performance, we convert the time series data of market trends into a market network and the time series data of the investor’s past judgments into an investor network. Then, we update these networks as new information arrives at the market and show the weighted in-degrees of the nodes in the market network and the investor network can represent the herding degree and the confidence degree of the investor, respectively. Using stock transaction data of Microsoft, US S&P 500 stock index, and China Hushen 300 stock index, we update the two networks and find that there exists a high similarity of network topological properties and a significant correlation of node parameter sequences between the market network and the investor network. Finally, we theoretically derive and conclude that the investor’s herding degree and confidence degree are highly related to each other when there is a clear market trend.
Improved carrier transport in Mn:ZnSe quantum dots sensitized La-doped nano-TiO2 thin film*
Authors: Li Shao , Li Gang , Yang Li-Shuang , Li Kui-Ying
Published: February 2020

Mn:ZnSe/ZnS/L-Cys core-shell quantum dots (QDs) sensitized La-doped nano-TiO2 thin film (QDSTF) was prepared. X-ray photoelectron spectroscopy (XPS), nanosecond transient photovoltaic (TPV), and steady state surface photovoltaic (SPV) technologies were used for probing the photoelectron behaviors in the Mn-doped QDSTF. The results revealed that the Mn-doped QDSTF had a p-type TPV characteristic. The bottom of the conduction band of the QDs as a sensitizer was just 0.86 eV above that of the La-doped nano-TiO2 thin film, while the acceptor level of the doped Mn2+ ions was located at about 0.39 eV below and near the bottom of the conduction band of the QDs. The intensity of the SPV response of the Mn-doped QDSTF at a specific wavelength was ∼2.1 times higher than that of the undoped QDSTF. The region of the SPV response of the Mn-doped QDSTF was extended by 191 nm to almost the whole visible region as compared with the undoped QDSTF one. And the region of the TPV response of the Mn-doped QDSTF was also obviously wider than that of the undoped QDSTF. These PV characteristics of the Mn-doped QDSTF may be due to the prolonged lifetime and extended diffusion length of photogenerated free charge carriers injected into the sensitized La-doped nano-TiO2 thin film.
In-situ SiN combined with etch-stop barrier structure for high-frequency AlGaN/GaN HEMT*
Authors: Mi Min-Han , Wu Sheng , Yang Ling , He Yun-Long , Hou Bin , Zhang Meng , Guo Li-Xin , Ma Xiao-Hua , Hao Yue
Published: February 2020

The etch-stop structure including the in-situ SiN and AlGaN/GaN barrier is proposed for high frequency applications. The etch-stop process is realized by placing an in-situ SiN layer on the top of the thin AlGaN barrier. F-based etching can be self-terminated after removing SiN, leaving the AlGaN barrier in the gate region. With this in-situ SiN and thin barrier etch-stop structure, the short channel effect can be suppressed, meanwhile achieving highly precisely controlled and low damage etching process. The device shows a maximum drain current of 1022 mA/mm, a peak transconductance of 459 mS/mm, and a maximum oscillation frequency (f
max) of 248 GHz.
Immunomodulation of surface biofunctionalized 3D printed porous titanium implants
Authors: Razzi F , Fratila-Apachitei L E , Fahy N , Bastiaansen-Jenniskens Y M , Apachitei I , Farrell E , Zadpoor A A
Published: February 2020

Additive manufacturing (AM) techniques have provided many opportunities for the rational design of porous metallic biomaterials with complex and precisely controlled topologies that give rise to unprecedented combinations of mechanical, physical, and biological properties. These favorable properties can be enhanced by surface biofunctionalization to enable full tissue regeneration and minimize the risk of implant-associated infections (IAIs). There is, however, an increasing need to investigate the immune responses triggered by surface biofunctionalized AM porous metals. Here, we studied the immunomodulatory effects of AM porous titanium (Ti-6Al-4V) printed using selective laser melting, and of two additional groups consisting of AM implants surface biofunctionalized using plasma electrolytic oxidation (PEO) with/without silver nanoparticles. The responses of human primary macrophages and human mesenchymal stromal cells (hMSCs) were studied in terms of cell viability, cell morphology and biomarkers of macrophage polarization. Non-treated AM porous titanium triggered a strong pro-inflammatory response in macrophages, albeit combined with signs of anti-inflammatory effects. The PEO treatment of AM porous titanium implants showed a higher potential to induce polarization towards a pro-repair macrophage phenotype. We detected no cytotoxicity against hMSCs in any of the groups. However, the incorporation of silver nanoparticles resulted in strong cytotoxicity against attached macrophages. The results of this study indicate the potential immunomodulatory effects of the AM porous titanium enhanced with PEO treatment, and point towards caution and further research when using silver nanoparticles for preventing IAIs.
Electronic, transport and optical properties in perovskite compound LaGaO3
Authors: Zitouni H , Tahiri N , El Bounagui O , Ez-Zahraouy H
Published: February 2020

The perovskite-type oxides ABO3 have a multifunctional application in different area such as promising new anode for rechargeable batteries (Ni/MH), photovoltaic and photochromic, because of their properties variety. In this work, we interested on the calculation of the electronic, optical and transport properties of the lanthanum gallate perovskite oxides compound, using the first-principles calculations based on the density functional theory. We determined the exchange and correlation effects by a Generalized Gradient Approximation of Perdew−Burke−Ernzerhof (GGA-PBE). As results the energy gaps of LaGaO3 compound with GGA-PBE have been found as 3.61 eV, from the transport properties we notice that LaGaO3 is P-type materials with electrical conductivity varied from 0 (Ω.m.s)−1 at 0 K to 10 × 1020 (Ω.m.s)−1 at 800 K.
Mechanical behavior, enhanced dc resistivity, energy band gap and high temperature magnetic properties of Y-substituted Mg–Zn ferrites
Authors: Ali M A , Khan M N I , Hossain M M , Chowdhury F-U-Z , Hossain M N , Rashid R , Hakim M A , Hoque S M , Uddin M M
Published: February 2020

We report the synthesis of Y-substituted Mg–Zn [Mg0.5Zn0.5Y
x
Fe2−x
O4 (0 ≤ x ≤ 0.05)] ferrites using conventional standard ceramic technique. The samples were characterized by x-ray diffraction (XRD) analysis, field emission scanning electron microscopy (FESEM), FTIR spectroscopy, UV–Vis spectroscopy and quantum design physical properties measurement system (PPMS). XRD patterns confirm the single phase cubic spinel structure up to x = 0.03 and appearance of a secondary phase of YFeO3 for higher Y contents. FESEM images depict the distribution of grains and EDS spectra confirmed the absence of any unwanted element. Completion of solid state reaction and formation of spinel structure has been revealed from FTIR spectra. The FTIR data along with lattice constant, bulk density and porosity were further used to calculate the stiffness constant (C
ij), elastic constant and Debye temperatures. Mechanical stability of all studied compositions is confirmed from C
ij using Born stability conditions. Brittleness and isotropic nature are also confirmed using Poisson’s ratio and anisotropy constants, respectively. The enhancement of dc electrical resistivity (105Ω cm to 106Ω cm) with Y content is observed. The energy band gap (increased with Y contents) is found in good agreement with dc electrical resistivity. Ferrimagnetic to paramagnetic phase change has been observed from the field dependent high temperature magnetization curves. The magnetic moments and saturation magnetization were found to be decreased with increasing temperature. The Curie temperature (Tc) has been measured from temperature dependent magnetic moment (M-T) and initial permeability (μ′i-T) measurements and found to be in good agreement with each other. Decrease in Tc with Y content is due to redistribution of cations and weakening of the exchange coupling constant. The magnetic phase transition has been analyzed by Arrott plot and found to have second order phase transition. The dc resistivity endorses the prepared ferrites are suitable for high frequency and high temperature magnetic device applications as well.
Silicon carbide color centers for quantum applications
Authors: Castelletto Stefania , Boretti Alberto
Published: February 2020

Silicon carbide has recently surged as an alternative material for scalable and integrated quantum photonics, as it is a host for naturally occurring color centers within its bandgap, emitting from the UV to the IR even at telecom wavelength. Some of these color centers have been proved to be characterized by quantum properties associated with their single-photon emission and their coherent spin state control, which make them ideal for quantum technology, such as quantum communication, computation, quantum sensing, metrology and can constitute the elements of future quantum networks. Due to its outstanding electrical, mechanical, and optical properties which extend to optical nonlinear properties, silicon carbide can also supply a more amenable platform for photonics devices with respect to other wide bandgap semiconductors, being already an unsurpassed material for high power microelectronics. In this review, we will summarize the current findings on this material color centers quantum properties such as quantum emission via optical and electrical excitation, optical spin polarization and coherent spin control and manipulation. Their fabrication methods are also summarized, showing the need for on-demand and nanometric control of the color centers fabrication location in the material. Their current applications in single-photon sources, quantum sensing of strain, magnetic and electric fields, spin-photon interface are also described. Finally, the efforts in the integration of these color centers in photonics devices and their fabrication challenges are described.
The Standardization of Islamic Financial Law: Lawmaking in Modern Financial Markets
Authors: Ercanbrack Jonathan
Published: February 2020

The project to standardize the commercial elements of the sharia as undertaken by standard-setting bodies, such as the Accounting and Auditing Organization for Islamic Financial Institutions (AAOIFI), is a lawmaking effort that is incentivized by market forces and the interaction of municipal legal systems. This Article examines the ways in which these factors contribute to the development of private Islamic legal standards, and in doing so, contribute to an emergent legal architecture that is integrated within the global economy. Contrary to the primary role assigned in existing analyses to sharia scholars and sharia supervisory boards, the Article shows that the processes that determine the composition of Islamic financial law (IFL) highlight the starkly reduced role of jurists in developing law in accordance with the traditional methodology (usul al-fiqh). Such analyses have failed to consider the standardization effort as a lawmaking project driven by market forces, which must be realized if authentic sharia principles are to be given effect. Therefore, examination of these market-led processes and their contribution to the creation of Islamic standards is essential for understanding what standardization means in relation to the fulfillment of Islamic principles and whether a high degree of standardization is desirable. First, the Article examines the role of interpretation, which highlights the methodological challenges of the standardization project. Second, the Article investigates the AAOIFI’s standard-setting efforts, including the methods of standardization, its market- and law-driven incentives, and the status of standardization efforts including the madhahib (schools of law)’s differences of legal thought. Third, an analysis of the interaction of IFL and the law of municipal legal systems (the United Arab Emirates, England and Wales, and Malaysia) highlights the legal incentivization for developing sharia standards. Finally, an analysis of the commercial practice of IFL, particularly in retail markets, demonstrates commercial law’s trend toward standardized contractual practices. Market forces compel the use of standard-form documentation, comprising standards that reflect the commercial practice of law firms and corporations.
Amplification of MDM2 and Loss of p16 Expression: Do They Have a Role in Malignant Transformation of Ovarian Brenner Tumor?
Authors: Wang Lucy , Allison Douglas , Shukla Pratibha Sharma
Published: February 2020

Objectives

To review the significance of MDM2 and cyclin D1 expression and loss of p16 expression in malignant and borderline Brenner tumors (BTs) of the ovary.

Methods

We describe 2 new cases of ovarian BT, 1 malignant and 1 borderline. We studied MDM2, p16, and cyclin D1 expression by immunohistochemistry in the benign, borderline, and malignant components of these 2 cases and in 5 additional cases of benign BT. We also reviewed and summarized the literature on the clinical, immunohistochemical and molecular characteristics of borderline and malignant BTs (BdBTs and MBTs).

Results

Nuclear expression of MDM2 was seen only in the MBT. Loss of p16 expression was seen in both BdBT and MBT. Cyclin D1 expression was in proportion to the degree of malignancy. Amplification of MDM2, loss of CDKN2A (p16-encoding gene), and amplification of CCND1 (cyclin D1–encoding gene) were confirmed by commercial next-generation sequencing in the case of MBT.

Conclusions

We are the first to report immunohistochemical expression of MDM2 in an MBT. Amplification of MDM2 and loss of p16 expression may have a role in malignant transformation of BT.
Florida’s Opioid Crackdown and Mortality From Drug Overdose, Motor Vehicle Crashes, and Suicide: A Bayesian Interrupted Time-Series Analysis
Authors: Feder Kenneth A , Mojtabai Ramin , Stuart Elizabeth A , Musci Rashelle , Letourneau Elizabeth J
Published: February 2020

In 2011, Florida established a prescription drug monitoring program and adopted new regulations for independent pain-management clinics. We examined the association of those reforms with drug overdose deaths and other injury fatalities. Florida’s postreform monthly mortality rates—for drug-involved deaths, motor vehicle crashes, and suicide by means other than poisoning—were compared with a counterfactual estimate of what those rates would have been absent reform. The counterfactual was estimated using a Bayesian structural time-series model based on mortality trends in similar states. By December 2013, drug overdose deaths were down 17% (95% credible interval: −21, −12), motor vehicle crash deaths were down 9% (95% credible interval: −14, −4), and suicide deaths were unchanged compared with what would be expected in the absence of reform. Florida’s opioid prescribing reform substantially reduced drug overdose deaths. Reforms may also have reduced motor vehicle crash deaths but were not associated with a change in suicides. More research is needed to understand these patterns. Bayesian structural time-series modeling is a promising new approach to interrupted time-series studies.
Vagueness-Induced Counterexamples to Modus Tollens
Authors: Beevers Tom
Published: February 2020

I argue that vagueness produces counterexamples to modus tollens. I begin by outlining cases where indicative and counterfactual conditionals (henceforth, natural conditionals) seem intuitively to be determinate even when their antecedents are borderline and their consequents are determinately false. Accepting these intuitions has some revisionary implications; however, rejecting them leads to unacceptable consequences for our knowledge of conditionals. I thus take it that we should accept that our intuitions are reliable. I show it follows that modus tollens fails. I conclude by defending this consequence from some objections.
The modified bilobed flap for reconstructing sacral decubitus ulcers
Authors: Jiao Xiangong , Cui Chunxiao , Ng Sally Kiu-Huen , Jiang Zhangjia , Tu Chihui , Zhou Jiemin , Lu Xiandong , Ouyang Xianwen , Luo Tong , Li Ke , Zhang Yixin
Published: February 2020

Background

Sacral pressure ulcers are associated with high morbidity and, in some cases, result in mortality from severe sepsis. Local flaps are frequently used for reconstruction of stage III and IV pressure ulcers. An ideal flap should be simple to design, have a reliable vascular supply and minimal donor site morbidity. Our study evaluates the use of a bilobed flap based on the superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery to reconstruct the sacral pressure ulcer.

Case presentation

We performed a retrospective analysis of paraplegic patients with sacral pressure ulcers treated with our bilobed flaps from January 2015 to December 2019. A description of our management, operative protocol, outcome and complications is outlined. Seven paraplegic patients (6 male, 1 female; average age 53.1 years) with sacral pressure ulcers were treated with our bilobed flap based on the superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery. The average size of the pressure ulcers was 7 × 5 cm (range 6.2 × 4.5 cm to 11 × 10 cm). All 7 flaps survived. The patients were followed up for 12 months without significant complications, such as flap necrosis or recurrence.

Conclusions

The superficial branch of the superior gluteal artery or the posterior branch of the fourth lumbar artery reliably supplies the bilobed flap. The superior cluneal nerve can be included in the design. The technique is simple and reliable. It should be included in the reconstructive algorithm for the management of sacral pressure ulcers.
Interdependence between health and peace: a call for a new paradigm
Authors: Abuelaish Izzeldin , Goodstadt Michael S , Mouhaffel Rim
Published: February 2020

Health and peace, and their relationships to disease/conflict/violence, are complex and multifaceted interrelated terms. Scholars have proposed a variety of definitions for health and peace. The conceptualizations of health and peace share many fundamental elements, including in their social, psychological (emotional and mental) and spiritual dimensions. We argue that health and peace are inter-dependent in a fundamental causal fashion. Health is always positively or negatively affected by conflict; peace can be directly or indirectly fostered through public health program and policy initiatives. Evidence shows that public health professionals and academics have frequently failed to recognize the inter-dependence of health and peace when conceptualizing, and addressing, issues related to health and peace. In contrast, the present article argues in support of a new paradigm for addressing public health issues related to health and peace; such a paradigm is based on the premise that health and peace are inextricably linked, requiring that they be addressed in an integrated, inter-dependent, fashion. Finally, we emphasize that fostering health and peace requires identifying and promoting positive socio-ecological influences on health, rather than limiting our focus to health deficits and obstacles at the individual or community levels.
Excellent long-term results with minimally invasive edge-to-edge repair in myxomatous degenerative mitral valve regurgitation
Authors: Belluschi Igor , Lapenna Elisabetta , Blasio Andrea , Del Forno Benedetto , Giacomini Andrea , Ruggeri Stefania , Schiavi Davide , Castiglioni Alessandro , Alfieri Ottavio , De Bonis Michele
Published: February 2020

OBJECTIVES

Previous series of minimally invasive mitral valve repairs showed excellent results at up to 10 years of follow-up. The goal of this study was to assess the long-term durability beyond 10 years of the edge-to-edge repair for myxomatous degeneration performed through a minimally invasive approach.

METHODS

Ninety-seven consecutive patients (mean age 35 ± 9 years; left ventricular ejection fraction 63 ± 6%) with severe myxomatous mitral regurgitation (MR) underwent mitral valve repair through a right minithoracotomy between 1999 and 2006. MR was due to lesions involving the posterior leaflet (7.2% of patients), anterior leaflet (12.4%) and both leaflets (80.4%).

RESULTS

No hospital deaths occurred. At hospital discharge all patients had no or trivial MR. Follow-up was 100% complete (median 15.5 years; interquartile range 13.6–17.0, max 19.3 years). The 16-year overall survival rate was 95.9 ± 2.02% [95% confidence interval (CI) 89.39–98.43]. At 16 years, the cumulative incidence function of cardiac death, with non-cardiac death as a competing risk, was 3.1 ± 1.75 (95% CI 0.83–8.02). Only 3 patients (4.1%) had redo operations for recurrent severe MR. At 16 years, the cumulative incidence functions of reoperation for and recurrence of MR ≥3+, with death as a competing risk, were 3.1 ± 1.76% (95% CI 0.83–8.02) and 5.6 ± 2.47% (95% CI 2.06–11.83), respectively. No predictors of recurrence of MR ≥3+ were identified. At the last follow-up, moderate MR (2+/4+) was detected in 17 patients (17.5%); most of the patients were in New York Heart Association functional class I–II (97%) and in sinus rhythm (90%).

CONCLUSIONS

Minimally invasive mitral valve edge-to-edge repair through a right minithoracotomy for myxomatous degeneration appears to be an effective and durable approach even in the long-term follow-up (up to 19 years).
Identifying dictionary-relevant formulaic sequences in written and spoken corpora
Authors: Dobrovoljc Kaja
Published: February 2020

In view of the pervasiveness of formulaic language in human communication and the growing awareness of its relevance to modern lexicography, this study presents a corpus-driven identification, analysis and comparison of dictionary-relevant formulaic sequences in reference corpora of written and spoken Slovenian. The sequences were identified using a semi-automatic approach, whereby the most frequently recurring word combinations in each corpus were ranked according to their statistical salience and manually inspected for formulaic expressions with lexicographic relevance. Despite its semantic heterogeneity, the resulting list illustrates the distinct characteristics of formulaic multi-word expressions, such as high frequency of usage, prevalent inclusion of grammatical words and common non-propositional meaning, especially in speech, where research revealed numerous understudied formulaic expressions related to interaction management and mitigation. The final evaluation of measures used in the identification process demonstrates their relative suitability for corpus-driven identification of dictionary-relevant formulaic expressions, with their precision varying in relation to corpus size and length of sequences under investigation.
Approximate controllability of semi-linear stochastic integro-differential equations with infinite delay
Authors: Huang Hai , Fu Xianlong
Published: February 2020

In this work, by constructing fundamental solutions and using the theory of resolvent operators and fractional powers of operators, we study the approximate controllability of a class of semi-linear stochastic integro-differential equations with infinite delay in $L_p$ space ($2<p<\infty $). Sufficient conditions for approximate controllability of the discussed equations are obtained under the assumption that the associated deterministic linear system is approximately controllable. An example is provided to illustrate the obtained results.
Analysis of Fat-Soluble Vitamins. XVIII. Interlaboratory Comparison of Vitamin D Assay Methods
Authors: Borsje Ben , Craenen Heinz A H , Esser Robert J E , Mulder Frits J , Vries Ellen J
Published: February 2020

Nine laboratories determined the vitamin D3 content of 4 samples in oil containing, in addition to vitamin D3, different amounts of tachysterol3, isotachysterol3, trans-vitamin D3, lumisterol3, and 7-dehydrocholesterol, in order to assess the effect of these isomers on the assay. The analyst selected the method to be used. Three high performance liquid chromatographic (HPLC) methods were applied: 2 were direct and the third required prior isolation of the unsaponifiable material. The 6 remaining analysts used gas-liquid chromatographic (CLC) methods; all GLC techniques required saponification and silylation, and 3 required an additional pretreatment. The results from the GLC and HPLC methods were compared with the known composition of the samples and the results obtained by the official AOAC method, 43.B14–43.B24. The samples were also analyzed by the AOAC method without the maleic anhydride reaction and by the AOAC method with correction for the isotachysterol content. The results of the HPLC assays showed that this technique is promising, but improvements are still needed. The precision and accuracy of the GLC assays varied. However, satisfactory results were obtained after extensive prepurifications. The AOAC chemical method was satisfactory for those samples shown suitable by the confirmation test, i.e., in the absence of isotachysterol.
Ion Exchange Method for Determining Mephentermine Sulfate in Drug Formulations: Collaborative Study
Authors: Chu Rod , Friedman Elaine J
Published: February 2020

Ion exchange chromatography is used to separate mephentermine sulfate from drug formulations. The drug is subsequently measured by ultraviolet spectrophotometry. Assays on 4 commercial samples of tablets and injectables gave recoveries from 97.6 to 104% of declared. A collaborative study involving 2 tablet and 2 liquid formulations gave mean recoveries ranging from 94.7 to 99.3% and coefficients of variation from 1.39 to 2.00%.
Quantitation of Polychlorinated Biphenyl Residues by Electron Capture Gas-Liquid Chromatography: Collaborative Study
Authors: Sawyer Leon D
Published: February 2020

Ten collaborators quantitated 2 synthetically prepared polychlorinated biphenyl (PCB) mixtures, 2 PCB-fortified milk samples, and an incurred PCB residue in milk and chicken fat. Three electron capture gas-liquid chromatographic (GLC) methods were used for quantitating each unknown PCB against Aroclor reference materials. Two of the methods were existing AOAC total response comparisons and the third was a proposed individual peak comparison. In addition, existing AOAC multiresidue pesticide methodology was employed for determining PCB recovery from whole milk. The average combined recovery of Aroclor 1254 from milk fortified at 1.4 and 2.7 ppm (fat) was approximately 85% (coefficient of variation, 15%) with no significant difference by the methods of quantitation. The incurred PCB residue in milk (as 1254) was determined to be 1.3 (30%), 1.7 (31%), and 1.2 ppm (18%) by total peak height, total area, and individual peak quantitation methods, respectively. In the same order, incurred PCB in chicken fat was determined to be 6.8 (13%), 7.5 (16%), and 5.6 ppm (8%) as 1242, or 6.9 (6%), 5.9 (8%), and 6.3 ppm (8%) as 1248. Total PCB quantitated individually in a 3- and a 4-component chlorobiphenyl mixture, using 1248 as the reference standard, resulted in the following averages of actual amounts present: 3-component—109% (23%), 95% (18%), and 95% (6%); 4-component— 116% (16%), 112% (29%), and 104% (7%), respectively, for total peak height, total area, and individual peak quantitation methods. Both the individual peak quantitation method and the AOAC multi-pesticide methodology have been adopted as official first action methods for PCB.
Spectrophotometric Determination of Pyrantel Tartrate in Swine Feeds by Method of Standard Additions: Collaborative Study
Authors: Litchman Mark A
Published: February 2020

The spectrophotometric method for pyrantel tartrate in swine feeds was collaboratively studied. Twenty-seven laboratories assayed feeds containing 0.0103, 0.0965, and 0.7902% pyrantel tartrate. Repeatability (σo) and reproducibility (ax) standard deviations were: σo = 0.00068%, σx = 0.00105% (10% of grand mean) for 0.0103% pyrantel tartrate level; σo = 0.0065%, σx = 0.0090% (10% of grand mean) for 0.0965% pyrantel tartrate level; and σo = 0.0415%, σx = 0.0743% (10% of grand mean) for 0.7902% pyrantel tartrate level. The mean theoretical recovery values for feeds containing 0.0103, 0.0965, and 0.7902% were 100, 97, and 96%, respectively. The method was adopted as official first action for feeds or concentrates containing 0.0106–0.8811% pyrantel tartrate.
High Pressure and Gas-Liquid Chromatographic Methods for the Determination of Parathion in Formulations: Collaborative Study
Authors: Jackson Edwin R
Published: February 2020

The official first action high pressure (HPLC) and gas-liquid (GLC) chromatographic methods for the determination of methyl parathion were adapted to analyze technical parathion, and 25 and 50% parathion emulsifiable concentrates. A technical parathion sample was analyzed and then used to prepare 5 of the 6 collaborative samples. At a 95% confidence level, only 1 of the 10 means was significantly different from the theoretical value. There was no significant difference in the CLC and HPLC means for each sample. The average of the coefficients of variation for the 6 CLC determinations (15 collaborators) was 0.86%. For the HPLC determinations (8 collaborators), the average was 0.81%.
Potential Uses of Lead Isotope Ratios in Gunshot Cases
Authors: Keisch Bernard , Callahan Robert C
Published: February 2020

The determination of lead isotope ratios in 14 bullets, and in material taken from 9 hand swabs and 5 primers shows that there are potentially valuable forensic uses for such a method. While a more complete study is required, this method could possibly be used to prove (or disprove) relationships between bullets and manufacturers, weapons, or persons firing the weapons. Sample size requirements (1 ≧g or less) are such that damaged or fragmented bullets, or minute particles therefrom, may be used for the required analyses. An experiment showed that gunshot residue from a test-fired weapon was detectable even after washing the hands.
Thin Layer Chromatographic Screening Method for Sulfadiazine Residues in Calf Tissues, Plasma, and Urine
Authors: Woolley Joseph L , Murch Oliver , Sigel Carl W
Published: February 2020

Because of the lack of specificity of the Bratton-Marshall procedure for assaying sulfonamides, a sensitive, specific tissue residue assay for sulfadiazine (SDZ) was developed. The methodology has been extended to provide a highly sensitive screen for sulfonamide residues, which employs 2-dimensional thin layer chromatography in conjunction with fluorescamine derivatization. The procedure described, which has been developed for SDZ in calf tissues, involves direct ethyl acetate extraction of tissue homogenates. Following evaporation of the organic phase, a portion of the residue is spotted on a 20x20 cm silica gel 60 plate, which is then developed in 2 dimensions with solvent systems devised to separate SDZ from endogenous substances as well as from 12 other sulfonamides that might be present in calf tissues. The presence of SDZ at a concentration of 0.1 ppm or its absence is easily demonstrated in calf kidney, liver, muscle, plasma, and urine. The basic method can be modified for a particular sulfonamide in a target tissue and can be used as a quantitative assay for sulfonamide residues.
Total Solids in Nonfat Dry Milk by Atmospheric Drying in a Forced Air Oven
Authors: Sherbon John W , Mickle James B , Ward William D
Published: February 2020

Laboratories using forced air atmospheric ovens at 100°C to determine total solids in milk are interested in using the same equipment to measure total solids in nonfat dry milk powder (NFDM). Results of several studies previously were presented to the Association. Another collaborative study involving 5 laboratories was done this year. The results of the new study confirm the previous work; the forced air method gives results not significantly different from the official vacuum oven procedure. Throughout these studies, it was noted that strong thermal gradients in some vacuum ovens made it difficult to uniformly subject each sample to the specified amount of heat. It was also found that fresh whole milk and reconstituted NFDM can be tested successfully when the steam bath step is omitted from the official method for milk by increasing the drying time to 4½ hr.
Methods of Analysis Approved by the Codex Alimentarius Commission. II. Determination of the Loss on Drying of Lactose: Collaborative Study1
Authors: Bourland Charles T , Weik Robert W , Anderson Randall L , Horwitz William
Published: February 2020

A collaborative study was performed on the method recommended by the Codex Alimentarius Commission for determining loss on drying of lactose at 120°C for 16 hr. Eight samples of lactose were analyzed by 9 laboratories. Although there was no significant difference between the means of the values obtained with the convection and forced draft ovens, the precision attained by the 3 laboratories using a forced draft oven was considerably better than that attained by the laboratories using a convection oven. There is evidence that the directions for preparing samples of coarse crystals and lumpy products are inadequate
Gas-Liquid Chromatographic Determination of Ethopabate in Feed Premixes
Authors: Smallidge Robert L
Published: February 2020

A gas-liquid chromatographic method is presented for determining ethopabate in 0.8 and 8.0% premixes. A sample is extracted with tetrahydrofuran containing an internal standard, by sonication or overnight soaking. The extract is clarified by centrifugation, diluted if necessary, and injected into a gas chromatograph equipped with a flame ionization detector. Average per cent recoveries for spiked blank samples were 100.6 at the 0.8% level and 100.4 at the 8.0% level. Precision, as indicated by replicate analyses of several premixes, ranged from 0.5 to 1.7% relative standard deviation
Colorimetric Determination of Terreic Acid Produced by Aspergillus terreus
Authors: Subramanian Thirugnana , Namasivayam Kuppuswamy Mohan , Shanmugasundaram Edayathimangalam R B
Published: February 2020

Two methods have been developed for determining terreic acid, which is a mycotoxin produced by Aspergillus terreus, a common food contaminant. The organism was grown independently in synthetic minimal medium, bread, and rice. After 15 days of growth, the toxin was extracted with ethyl acetate, cleaned up by thin layer chromatography, and determined colorimetrically, using Folin's reagent or 2,4- dinitrophenylhydrazine. The production of terreic acid was greater on bread than on rice or minimal medium. Recoveries of 200–400 ≧g terreic acid/100 g bread and rice ranged from 62 to 98%. The lower limit of detection was 200 ≧g/100 g.
High Pressure Liquid Chromatographic Determination of Xanthomegnin in Corn
Authors: Stack Michael E , Brown Nathan L , Eppley Robert M
Published: February 2020

A method is described for the detection and quantitative analysis of xanthomegnin in corn samples. Initial extraction with CHCI3 in the presence of 0.5M H3PO4 is followed by additional purification using silica gel column chromatography. A high pressure liquid chromatograph equipped with a microparticle silica gel column and a 405 nm absorbance detector is used for detection and quantitation of the xanthomegnin. The identity of xanthomegnin is confirmed by thin layer chromatography on silica gel plates developed with benzenemethanol- acetic acid (90-(-5+5). The recovery of xanthomegnin added to corn samples at levels of 0.75–9.6 mg/kg averaged 41% with a coefficient of variation of 25%.
Purity of Schaeffer's Salt
Authors: Marmion Daniel M
Published: February 2020

Twenty-one samples of Schaeffer's salt from 8 countries were evaluated for purity, using a variety of instrumental and chemical methods. The properties considered include strength, moisture, insoluble materials, inorganic salts, 2-naphthol, 2-naphthol-3,6-disulfonic acid, 2-naphthol-6,8-disulfonic acid, 6,6'-oxybis(2- naphthalenesulfonic acid), pH, ultraviolet purity, and absorptivity. One unknown was detected in the samples studied, and poor analytical totals obtained on several samples suggest the possible presence of others.
Gas-Liquid Chromatographic Quantitation of Cocaine.HC1 in Powders and Tablets: Collaborative Study
Authors: Clark Charles C
Published: February 2020

Eight laboratories collaboratively studied a method for the quantitative gas-liquid chromatographic (GLC) determination of cocaine. HC1 in solid forms. The cocaine.HQ and other water solubles are dissolved in dilute HC1. The aqueous solution is made weakly basic with K2HPO4, and the organic solubles are extracted into CHC13 for the GLC determination of cocaine. Tetracosane (n-C24) is incorporated in the extracting CHC13 as an internal standard. Five samples of known cocaine.HC1 concentration and one sample of commercial ground tablets were collaboratively studied. The cocaine. HC1 content ranged from 6 to 100%. Recoveries ranged from 98.7 to 103%; coefficients of variation ranged from 0.89 to 3.16. The method was adopted as official first action.
Separation of Krebs Cycle Acids with Beaded Diethylaminoethyl Cellulose
Authors: Bruinsma Bernard L , Le Tourneau Duane
Published: February 2020

A method is described for separating Krebs cycle organic acids on a column of beaded diethylaminoethyl cellulose (DEAE Sephadex A-25). Depending on the acids contained in the mixture, separation can be achieved in 4–8 hr and does not require pH or solvent gradients. After elution, the solvent (ethyl ether-formic acid-water (10+2-(-l)) is removed in a vacuum oven (aspirator). The contents of the tubes can be titrated for quantitative analyses or pooled, recrystallized, and used for qualitative analyses, such as infrared spectroscopy. The method was used to separate and isolate fumaric, a-ketoglutaric, malic, oxalic and succinic acids from culture medium following the growth of the fungus Sclerotinia sclerotiorum (Lib.) D. By.
Method for Maintaining Viability of Clostridium perfringens in Foods During Shipment and Storage: Collaborative Study
Authors: Harmon Stanley M , Placencia Ana M
Published: February 2020

A collaborative study was conducted in 12 laboratories to determine the effectiveness of a new method for maintaining vegetative cells of Clostridium perfringens in viable condition during storage and transport of food specimens to the laboratory. The collaborative results showed that treatment of brown gravy and roast beef samples with an equal amount by weight of sterile buffered glycerol-sodium chloride solution to give a final 10% glycerol concentration and storage with Dry Ice for 10 days at — 56°C resulted in plate counts of C. perfringens which were 2—4 log cycles higher with 2 different strains than counts with untreated specimens stored by the usual method at — 20°C. Plate counts obtained with the treated specimens stored with Dry Ice were less than 1 log cycle lower than counts made with identical specimens before freezing for storage and shipment to the collaborators. The results with treated specimens were also more uniform among the different laboratories. Because the new method for storage and shipment of food samples was so effective for maintaining viability of the organism, the official first action method for C. perfringens (46.B01) was changed to incorporate these procedures as part of the method.
High Pressure Liquid Chromatography of Zearalenone in Cereals
Authors: Möller Tord E , Josefsson Egon
Published: February 2020

A high pressure liquid chromatographic method has been developed for determining zearalenone in cereals. The sample is extracted with phosphoric acid and chloroform. The extract is cleaned up by washing on a silica gel column with benzene-hexane or cyclohexaneethylene dichloride-ethyl ether and eluting with chloroform, and further purified by extracting into alkaline solution, washing with water, adjusting pH, and back-extracting into chloroform. Zearalenone is determined by using a liquid chromatograph with 2 columns in series packed with Spherisorb 10 μm ODS and with an ultraviolet detector set at 236 nm. The detection limit of the method is 2 μg/kg. Recovery is about 90% when benzene-hexane is used in the washing step and about 80% when cyclohexane-ethylene dichloride-ethyl ether is used.
Confirmatory Test for Aflatoxin M1 on a Thin Layer Plate
Authors: Van Egmond Hans P , Paulsch Walter E , Schuller Pieter L
Published: February 2020

The identity of aflatoxin M1 can easily be confirmed directly on a thin layer plate by reacting aflatoxin M1 with trifluoroacetic acid (TFA). This confirmation reaction is carried out on the thin layer plate which has been developed in 2 dimensions and used for the quantitation of aflatoxin M1 in the sample. TFA is superimposed on the separated M1 spot. The plate is kept in the dark 3 min, heated to 75°C for 5 min, and developed with chloroformmethanol-acetic acid-water (92+8+2+0.8). The Rf value of the blue-fluorescent derivative is compared with that for the M1 standard. The method was used successfully on extracts of milk, cheese, and liver. M1 quantities on the plate as low as 0.5 ng can be confirmed by this method. The method is also suitable for simultaneous confirmation of aflatoxin B1.
Gas-Liquid Chromatographic Determination of Pydrin, a Synthetic Pyrethroid, in Cabbage and Lettuce
Authors: Lee Young W , Westcott Neil D , Reichle Randy A
Published: February 2020

Pydrin, a-cyano-3-phenoxybenzyI 2-(4-chlorophenyl)-3-methylbutyrate, a synthetic pyrethroid ester, is extracted from vegetables with acetonitrile, partitioned into petroleum ether before cleanup on a Florisil column, and analyzed by electron capture gas-liquid chromatography. Recoveries of 88-102% at 0.01 ppm, 99-102% at 0.1 ppm, and 98—104% at 1.0 ppm were obtained from fortified cabbage and lettuce samples. The method appears applicable to detection of the residues of Pydrin in the foliage of many types of crops.
Extraction of Light Filth from Coconut: Collaborative Study
Authors: Thrasher Joel J
Published: February 2020

The official method for filth in coconut, 44.029, frequently produces filter papers with excessive plant debris and low hair recoveries. To overcome these deficiencies, 3 changes in the method were made: (1) the defatting step was modified to use sodium lauryl sulfate in combination with borax for better defatting; (2) 40% isopropanol was substituted for 60% ethanol as the aqueous phase for cleaner papers; and (3) mineral oil was substituted for n-heptane to improve hair recoveries. These changes resulted in higher, more reproducible recoveries of rodent hairs and insect fragments and cleaner filter papers. The method has been adopted as official first action to replace 44.029.
Improved Fluorometric Method for Determining Selenium
Authors: Whetter Phyllis A , Ullrey Duane E
Published: February 2020

A previously reported method for selenium analysis of biological materials has been modified to reduce equipment requirements and labor, resulting in 40—80 determinations in an 8-hr period. Digestions are performed on hot plates in Erlenmeyer flasks, and neutralization, chelation with EDTA, complexing with 2,3- diaminonaphthalene, and extraction of the piazoselenol into cyclohexane are completed in the same vessel. Flotation of the cyclohexane layer into the neck of the flask with water allows convenient transfer to fluorometer tubes. Representative analytical values for serum, skeletal muscle, liver, kidney, corn, and alfalfa hay are presented. The mean recovery (± standard deviation) of added selenite selenium in 84 determinations was 98.1±7.1%. The mean coefficient of variation (± standard error) of repeated analyses of the same samples was 6.98±0.78%. The mean difference (± standard error) between values determined by the proposed method and the AOAC method was -0.03±0.60%.