Simulated Particle and Vapor Drift of Dicamba to ‘Vidal blanc’ Hybrid Grapevine under Missouri Field Conditions

The increasing adoption of dicamba-tolerant soybean (Glycine max) increases the potential exposure of wine grape (Vitis sp.) to dicamba, to which off-target injury may occur via particle drift or vapor drift. In Missouri, at one site in 2017 and at two sites in 2018, research of production vineyards focused on the effects of dicamba on hybrid ‘Vidal blanc’ grapevines. During flowering and early fruit set, bearing grapevines were exposed to low rates of dicamba delivered as a spray solution of 81 or 161 ppm or by vapor from treated soil. Grapevines were highly sensitive to dicamba, and visible symptoms extended throughout the growing season. The severity of dicamba injury (leaf cupping and feathering) was similar at two of three site-years, with greater injury related to particle drift than to vapor drift of dicamba. Early-season injury resulted in dicamba impacting the total soluble solids (TSS) content of grape berries and grape yield. At harvest during two site-years, yield reductions of up to 45% were associated with dicamba exposure at flowering. Across all site-years, no significant effects of dicamba drift were observed in the TSS content of berries during veraison in August, as measured by refractometer. However, the final TSS content of berries at harvest in September was reduced by 12% from dicamba as particle drift. At a minimum detection level of 10 ng⋅mL−1, high-performance liquid chromatography mass spectrometry identified dicamba at levels up to 33 ng⋅mL−1 in grape must over all site-years. Unexpectedly, this was up to 125 d after grapevine exposure despite low levels of visible dicamba symptomology.

Individual Monitoring of Internal Exposure for Nuclear Medicine Workers in NINMAS through In-Vitro Bioassay Techniques

Internal radiation monitoring of occupational radiation workers is essential for protecting them against the risks of incorporated radionuclides. More than 400 workers in Bangladesh are working with unsealed radioactive sources and most of them are employed at different nuclear facilities. Among the 18 Nuclear Medicine Centers in the country, the National Institute of Nuclear Medicine and Allied Science (NINMAS), Dhaka was selected for this study where workers get internal radiation exposure while processing and labeling of the liquid sources. The aim of this study was to estimate the activity concentration and committed effective doses from bioassay sample, namely urine samples of Nuclear Medicine (NM) workers due to handling of radioactive Iodine (131I), Technetium (99mTc) and Fluorine (F-18). Total 86 urine samples were collected from 17 occupational workers of NINMAS during the year 2017 and analyzed using High Purity Germanium (HPGe) detector. The radioactivity of 131I and (99mTc) was found 2.21±0.44 BqL-1 to 444 ± 39.91 BqL-1 and 5.53±1.12 BqL-1 to 603 ± 72.36 BqL-1 respectively. Due to low activity of the unsealed F-18 sources and for appropriate shielding, radioactivity of F-18 was found below the minimum detection level in the urine samples of the workers who handled it. The effective doses of occupational workers have also been calculated using the radioactivity concentration and the dose coefficients given in ICRP publication 78. The highest and lowest effective doses due to handling of the unsealed source of (99mTc) were 28.2 and 0.0258μSv for working with 780 and 36mCi of radionuclide respectively. On the other hand, the highest and lowest effective doses due to handling of 131I were 8.73and 0.045μSv, for working with 1425 and 55 mCi respectively. Both the doses are found to comply with ICRP annual dose limit of 20 mSv. Bangladesh J. Nuclear Med. 22(2): 125-129, Jul 2019

Improvement in the Detection of Cystic Metastatic Papillary Thyroid Carcinoma by Measurement of Thyroglobulin in Aspirated Fluid

Cystic change in metastatic lymph nodes of papillary thyroid carcinoma (PTC) is a diagnostic challenge for fine needle aspiration (FNA) because of the scant cellularity. The aim of this study was to evaluate the measurement of thyroglobulin in fine needle aspirate (Tg-FNA) for detecting metastatic PTC in patients with cystic neck lesions and to validate the optimal cutoff value of Tg-FNA. A total of 75 FNA specimens of cystic lesions were identified, including 40 of metastatic PTC. Predetermined threshold levels of 0.04 (minimum detection level), 0.9, 10.0, and 77.0 ng/mL (maximum normal serum-Tg level) were used to evaluate the diagnostic accuracy of Tg-FNA for metastatic PTC detection. The areas under the receiver operating characteristic curve for diagnosing metastatic PTC of Tg-FNA values of 0.04, 0.9, 10.0, and 77.0 ng/mL were 0.5 (95% confidence interval [CI], 0.382–0.618), 0.645 (95% CI, 0.526–0.752), 0.945 (95% CI, 0.866–0.984), and 0.973 (95% CI, 0.907–0.996), respectively. With a cutoff value of 77.0 ng/mL, the combination of Tg-FNA and FNA cytology showed superior diagnostic power (97.5% sensitivity and 100% specificity) compared to FNA cytology alone (80% sensitivity and 100% specificity). We recommend a Tg-FNA cutoff of 77.0 ng/mL, the maximum normal serum-Tg level, for cystic neck lesions.

First Molecular Detection of Ramularia Leaf Spot (Ramularia collo-cygni) in Seeds and Leaves of Barley in Argentina

The fungus Ramularia collo-cygni B. Sutton & J. M. Waller (Rcc) was identified as the causal agent of this emerging disease on barley (Hordeum vulgare L.) based on symptoms and signs on leaves and attributes of the fungus. The common name given to the disease was “necrotic sprinkling.” This disease was found for the first time on barley in fields of Buenos Aires Province, Argentina, in 2001, with severities ranging from 60 to 100% (2). During the spring of 2012, the disease spread throughout most barley growing areas of the Pampean region, affecting almost all varieties of barley in the Buenos Aires, Entre Ríos, and Santa Fe provinces. The disease showed typical symptoms of small, brown spots on leaves, sheaths, and awns, and caused rapid loss of green leaf area and significant economic damage. The diagnosis of this disease is difficult by conventional techniques and has caused some confusion. In order to obtain appropriate information about the incidence of this pathogen in the most important barley growing region of Argentina, as well as to confirm its presence on seed, 39 seed samples containing 200 seeds each and eight leaf samples were analyzed using a real-time PCR diagnostic test (4). Thirty-five of the 37 seed samples had Rcc DNA levels above the minimum detection level (0.13 pg DNA). Ramularia has been described as a seedborne fungus previously (1) and seed infection could hasten the spread of the fungus to new geographically distinct areas. Moreover, leaf samples were microscopically assessed for conidophore presence and then ground for DNA extraction. Rcc DNA was detected by PCR in all eight leaf samples. To our knowledge, this is the first report about molecular detection of R. collo-cygni in barley seed of harvested samples from Argentina. Seeds infected/infested may also lead to new strains of the fungus arriving in barley fields and provide a source of inoculum for future epidemics (3). References: (1) N. D. Havis et al. FEMS Microbiol. Lett. 256:217, 2006. (2) M. Khier et al. Salpicado necrótico, nueva enfermedad de la cebada en Argentina causada por Ramularia collo-cygni. Page 47 in: Resúmenes XI Jornadas Fitosanitarias Argentinas, 26–29 June 2002, Río Cuarto, Córdoba, 2002. (3) P. Matusinsky et al. J. Plant Pathol. 3:679, 2011. (4) J. M. G. Taylor et al. Lett. Appl. Microbiol. 50:493, 2010.

Assessment of humoral and cell-mediated immunity againstBordetella pertussisin adolescent, adult, and senior subjects in Italy

SUMMARYHumoral and cell-mediated immunity (CMI) againstB. pertussiswas assessed in a sample of adolescent, adult and senior subjects distributed in five different geographical areas in Italy. Most (99·1%) subjects had IgG anti-pertussis toxin (PT) antibodies exceeding the minimum detection level [⩾2 ELISA units (EU)/ml]. There were no significant differences between the genders; 6·2% samples recorded titres ⩾100 EU/ml. CMI was positive [stimulation index (SI) ⩾5] against PT in 39·0% of all samples. This study suggests thatB. pertussiscontinues to circulate in age groups that have been previously considered to be uninvolved in the circulation of this pathogen and that adolescent and adult pertussis boosters may be of value in these populations. Nevertheless, over the last 10 years, large increases in vaccination coverage rates have contributed to reduce the spread of the aetiological agent, especially in the immunized population.

Microfabricated Device for Impedance-Based Detection of Bacterial Metabolism

We present the use of a microfabricated device for impedance-based detection of a few live bacterial cells. Impedance-based detection relies on measuring changes in the AC impedance of two electrodes immersed in a liquid were the bacteria are cultured, caused by the release of ionic species by metabolizing bacterial cells. Rapid detection of a few cells (1 to 10) is possible if the cells are confined into a volume on the order of nanoliters. A microfluidic biochip prototype has been fabricated to test this miniaturized assay. The conductance of the bacterial suspensions is extracted from measuring their complex impedance in a 5.27 nl chamber in the biochip, at several frequencies between 100 Hz and 1 MHz. Measurements on suspensions of the bacteria Listeria innocua, Listeria monocytogenes, and Escherichia coli in a low conductivity buffer demonstrate that, under the current experimental conditions, the minimum detection level is between 50 and 200 live cells, after two hours of off-chip incubation. Work is in progress to develop techniques for selective capture of bacteria inside the chip, and to minimize background changes in impedance during on-chip incubation.

In-depth Analysis of the Impurities in GaN

GaN epitaxial films were analyzed by Secondary Ion Mass Spectrometry (SIMS). Standard implanted samples were used to determine the appropriate analytical conditions for analysis of impurities. The dose and energy of implantation for selected elements (Mg, Al, Si, Zn, Cd, H, C and O) were chosen so the maximum impurity concentration was not more than 1020 atoms/cm3. The optimum analysis conditions were ascertained from the standards for each element, and the detection limits were deduced from the background levels of the implantation profiles. We demonstate that lower detection limits of 1015 atoms/cm3 with a dynamic range 103 − 105 are possible. Zn and Cd have low ion yields, so the minimum detection level for these elements is the background level of the detector. The detection limits of the other elements are determined by the contamination of an initial GaN matrix.

HPLC Receptorgram: A Method for Confirmation and Identification of Antimicrobial Drugs by Using Liquid Chromatography with Microbial Receptor Assay. I. Sulfonamides in Milk

A determinative method was developed for confirmation, identification, and quantitation of 12 sulfonamide residues and p-aminobenzoic acid (PABA) in milk. This method, termed "HPLC receptorgram," uses liquid chromatography in conjunction with the microbial receptor assay (MRA) to monitor sulfonamides. The MRA for sulfonamides (commercialized as the Charm II test) uses a microcrobial receptor and [3H]sulfamethazine tracer. Sulfonamides in milk bind to the receptor and inhibit the binding of the tracer to the receptor. Milk samples spiked at 10 ppb for each sulfonamide result in at least a 50% decrease in binding on the HPLC receptorgram, with the exception of sulfanilamide and sulfacetamide, which give approximately a 25% decrease. Additionally, milk samples spiked at the minimum detection level of the MRA assay can be confirmed, identified, and quantitated with coefficients of variation (%) of 7.6-24. Analysis of market milk samples found positive by the MRA showed 9 samples containing sulfamethazine, 4 samples containing sulfadimethoxine, 2 samples containing sulfadoxine, 2 samples containing sulfadiazine or sulfathiazole, and 1 sample each containing sulfisoxazole or sulfapyridine. Three samples contained multiple sulfonamide residues. Ten sulfonamides are determined with an isocratic buffer elution system containing 22% acetonitrile mobile phase. p-Aminobenzoic acid (PABA), an interfering sulfonamide analog, sulfanilamide, and sulfacetamide are eluted by using a 10% acetonitrile mobile phase

Quantitative electron probe microanalysis of Be in Nb-Be alloys using an a-factor correction technique

With the advent of Multilayered Dispersion Elements (MLDE) it is now possible to routinely analyze beryllium in the electron microprobe. In NbBe binary alloys the Be x-ray yield is high enough to allow accurate quantitative analysis of this ultralight element. An empirical correction technique, in conjunction with NbBe standards, enables Be intensities to be converted into concentrations. The minimum detection level of Be in Nb is estimated to be less than 0.05 weight percent.series of NbBe binary alloys and Be metal were examined with an electron microprobe. Very favorable Be Ka peak intensities and P/B ratios were obtained with a Boron Carbide/Molybdenum MLDE (2d= 203.6 A ). These values are reported in Table 1. Because of many factors, including the probable high absorption of the ultra-soft Be x rays in the matrix and the huge overvoltages affronted, traditional correction procedures such as ZAF can be expected to fail.