Dissipation kinetics, residues and risk assessment of propiconazole and azoxystrobin in ginseng and soil

<p>The combinational fungicide suspension (11.7% propiconazole + 7% azoxystrobin), developed by Syngenta Co., Ltd., is very effective for the control of Alternaria black spot on ginseng. A simple and effective method was developed for determining propiconazole and azoxystrobin residues by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The recoveries of propiconazole ranged from 81.0% to 98.0% with relative standard deviations (RSDs) of 1.23–8.46%, while the recoveries of azoxystrobin ranged from 83.2% to 98.8% with RSDs of 3.29–9.50%. For the dissipation kinetics, the combinational fungicide was sprayed with dosage of 225 g a.i.ha⁻¹ (1.5 times of recommended dosage) in ginseng and soil at two different locations. The dissipation kinetics followed the first-order kinetics with half-lives of 6.66–13.33 days for propiconazole and 4.92–9.12 days for azoxystrobin. Based on the terminal residues data, the preharvest interval (PHI) could be 35 days at recommended dosage in ginseng. The dietary exposure risk was estimated by risk quotient (RQ). The result showed that the RQ value was obviously lower than RQ = 1, indicating that spraying propiconazole and azoxystrobin in ginseng at recommended dosage was safe for human beings.</p

Isolation Strategies and Transformation Behaviors of Spironolactone Forms

Spironolactone (SPI) is one kind of potassium-sparing diuretic, and two polymorphs (form I and form II) along with five solvates (methanol, ethanol, acetonitrile, ethyl acetate, and benzene) of SPI have been reported in the literature. However, no detailed information about the stability, solubility, and transformation behaviors of SPI forms has been reported. In this paper, two new forms of SPI, 1-propanol solvate and 2-propanol solvate, were found and characterized. The thermodynamic stability and solubility of form II and four alcohol solvates of SPI were investigated and determined. It was found that methanol solvate and ethanol solvate of SPI are relatively stable while 1-propanol solvate and 2-propanol solvate of SPI are metastable in corresponding solvents, and 1-propanol solvate and 2-propanol solvate of SPI would transform to form II in corresponding solvents. Furthermore, the transformation processes of 1-propanol solvate and 2-propanol solvate were in situ monitored by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and Raman spectroscopy and some offline tools such as microscopy and powder X-ray diffraction (PXRD). The reasons behind the transformation were explained by the enthalpy data of different solvates

2-kV thyristor triggered in impact-ionization wave mode by a solid-state spiral generator

Impact-ionization wave triggering of a thyristor enables it to switch significantly higher currents with much faster rise times (d I /d t ) than through conventional triggering; indeed tests on commercial components demonstrate that both current and d I /d t can be increased an order of magnitude over their specified datasheet values by utilizing impact ionization. However, creating an impact ionization wave places stringent requirements on the generator used to trigger the thyristor—particularly the trigger pulse must have a voltage rise rate (d V /d t ) of more than 1 kV/ns and an amplitude over twice the thyristors static breakdown voltage. Given the capacitance of a thyristor is relatively large, often hundreds of pF, this is difficult to achieve with many common triggering methods. In this study, we present a bespoke, cost-effective, trigger generator that has been developed based on spiral/vector inversion techniques coupled to an optimized sharpening circuit. Using this generator, both a 2-kV single thyristor and a 4-kV stack of two thyristors in series were triggered in the impact-ionization mode. The thyristors had a wafer diameter of 32 mm and capacitances of 370 pF. With a single thyristor 100 shots were performed with it switching a peak current of 1.25 kA and an associated d I /d t of 12 kA/ μ s. With two thyristors, peak currents of 2.6 kA and with d I /d t of 25 kA/ μ s were achieved. In all experiments no degradation of the semiconductor structure was observed. The work opens the way for developing very powerful, but still compact, solid-state trigger generators and larger pulsers for a wide range of pulsed power applications. </p

Data_Sheet_1_Assessing heterogeneity of patient and health system delay among TB in a population with internal migrants in China.docx

BackgroundsThe diagnostic delay of tuberculosis (TB) contributes to further transmission and impedes the implementation of the End TB Strategy. Therefore, we aimed to describe the characteristics of patient delay, health system delay, and total delay among TB patients in Shanghai, identify areas at high risk for delay, and explore the potential factors of long delay at individual and spatial levels.MethodThe study included TB patients among migrants and residents in Shanghai between January 2010 and December 2018. Patient and health system delays exceeding 14 days and total delays exceeding 28 days were defined as long delays. Time trends of long delays were evaluated by Joinpoint regression. Multivariable logistic regression analysis was employed to analyze influencing factors of long delays. Spatial analysis of delays was conducted using ArcGIS, and the hierarchical Bayesian spatial model was utilized to explore associated spatial factors.ResultsOverall, 61,050 TB patients were notified during the study period. Median patient, health system, and total delays were 12 days (IQR: 3–26), 9 days (IQR: 4–18), and 27 days (IQR: 15–43), respectively. Migrants, females, older adults, symptomatic visits to TB-designated facilities, and pathogen-positive were associated with longer patient delays, while pathogen-negative, active case findings and symptomatic visits to non-TB-designated facilities were associated with long health system delays (LHD). Spatial analysis revealed Chongming Island was a hotspot for patient delay, while western areas of Shanghai, with a high proportion of internal migrants and industrial parks, were at high risk for LHD. The application of rapid molecular diagnostic methods was associated with reduced health system delays.ConclusionDespite a relatively shorter diagnostic delay of TB than in the other regions in China, there was vital social-demographic and spatial heterogeneity in the occurrence of long delays in Shanghai. While the active case finding and rapid molecular diagnosis reduced the delay, novel targeted interventions are still required to address the challenges of TB diagnosis among both migrants and residents in this urban setting.</p

Data_Sheet_1_Assessing heterogeneity of patient and health system delay among TB in a population with internal migrants in China.docx

BackgroundsThe diagnostic delay of tuberculosis (TB) contributes to further transmission and impedes the implementation of the End TB Strategy. Therefore, we aimed to describe the characteristics of patient delay, health system delay, and total delay among TB patients in Shanghai, identify areas at high risk for delay, and explore the potential factors of long delay at individual and spatial levels.MethodThe study included TB patients among migrants and residents in Shanghai between January 2010 and December 2018. Patient and health system delays exceeding 14 days and total delays exceeding 28 days were defined as long delays. Time trends of long delays were evaluated by Joinpoint regression. Multivariable logistic regression analysis was employed to analyze influencing factors of long delays. Spatial analysis of delays was conducted using ArcGIS, and the hierarchical Bayesian spatial model was utilized to explore associated spatial factors.ResultsOverall, 61,050 TB patients were notified during the study period. Median patient, health system, and total delays were 12 days (IQR: 3–26), 9 days (IQR: 4–18), and 27 days (IQR: 15–43), respectively. Migrants, females, older adults, symptomatic visits to TB-designated facilities, and pathogen-positive were associated with longer patient delays, while pathogen-negative, active case findings and symptomatic visits to non-TB-designated facilities were associated with long health system delays (LHD). Spatial analysis revealed Chongming Island was a hotspot for patient delay, while western areas of Shanghai, with a high proportion of internal migrants and industrial parks, were at high risk for LHD. The application of rapid molecular diagnostic methods was associated with reduced health system delays.ConclusionDespite a relatively shorter diagnostic delay of TB than in the other regions in China, there was vital social-demographic and spatial heterogeneity in the occurrence of long delays in Shanghai. While the active case finding and rapid molecular diagnosis reduced the delay, novel targeted interventions are still required to address the challenges of TB diagnosis among both migrants and residents in this urban setting.</p