Simultaneous determination of 13 mycotoxins in feedstuffs using QuEChERS extraction

Mycotoxins are secondary metabolites produced by various fungi and are known to have a significant negative impact on human and animal health. When feedstuffs are contaminated with mycotoxins, their toxicities may be caused a variety of diseases. In this study, the residual mycotoxins in feedstuffs were analyzed using LC-MS/MS incorporated with QuEChERS extraction. Analytical method validation was performed for LOD, LOQ, linearity, and recoveries with consideration of matrix effects prior to the residual analysis. They were all reached to the accepted range of validation level. Using 39 feedstuff samples (5 g) for mycotoxin analysis, nine samples were contaminated by four major mycotoxins such as fumonisin B1 (FB1), deoxynivalenol, fumonisin B2, and zearalenone. Among them, FB1 was detected at the highest concentration as 18.0943 mg/kg. The total sum of fumonisins in 39 samples did not exceed the maximum residual level (MRL) criterion set by Korean Food and Drug Administration. Altogether, intensive management of mycotoxins in Korean feedstuffs should be implemented with proper and routine monitoring, even their residual concentrations are not exceeded over the MRL levels because of high frequent detection found in this study

Analysis of Multiresidue Pesticides in Agricultural Paddy Soils Near Industrial Areas in Korea by GC–MS/MS and LC–MS/MS Using QuEChERS Extraction with dSPE Clean-Up

Pesticides have been used to control pests in agricultural fields and storage systems before circulating agricultural products to markets. A tandem mass spectrometry, equipped with gas chromatographic separation (GC–MS/MS) or ultra-performance liquid chromatographic separation (LC–MS/MS), was used to monitor residual pesticides in Korean rice paddy soils. Selective multiple reaction monitoring was employed during the analyses to achieve multiresidue pesticide analysis using GC–MS/MS and LC–MS/MS of 342 pesticides. In this study, QuEChERS extraction was employed with a dSPE clean-up to establish an effective pretreatment process. The limit of detection (LOD) and limit of quantification (LOQ) were set up for all pesticides, and method validation was performed for linearity and recovery at levels of 10 and 50 mg kg−1 in the untreated soil sample. All pesticides satisfied the acceptable recovery range of 70–120%, within less than 20% RSD values, except for ametoctradin and gibberellic acid. In the paddy soil analyses, tricyclazole was the most frequently detectable pesticide, followed by oxadiazon, endosulfan, and chlorantraniliprole. Continuous monitoring of residual pesticides in paddy soils should be conducted due to the translocation of some systemic pesticides from soils to crop plants, and the impact of residual pesticides on the environment

Endoscopic Management of Anastomotic Strictures after Liver Transplantation

Endoscopic treatment of biliary strictures involving plastic stent placement has been used widely. The use of self-expandable metal stents (SEMSs) has been described for anastomotic strictures following liver transplantation (LT). This review aimed to assess and compare the efficacy of plastic stents with SEMS in LT patients. Information was retrieved regarding technical success, stricture resolution, the number of endoscopic retrograde cholangiography procedures, follow-up, immediate, and late complications. Eight studies involving plastic stents had a stricture resolution rate of 84.5%, with the rates ranging from 63% to 100%. These rates are comparable with the stricture resolution rate of 75% determined from six studies that involved 236 patients who received metal stents and the rates ranged from 53% to 81%. The observed success rate for metal stents used to manage post-LT anastomotic biliary strictures was below the reported rate for multiple plastic stents. Hence, the currently available metal stents should not be offered for the management of post-LT anastomotic biliary strictures

Effects of grain size on the dielectric properties and tunabilities of sol-gel derived Ba(Zr0.2Ti0.8)O3 ceramics

The effects of the average grain size on the phase transformation and consequent changes in the dielectric properties of Pb(Mg1/3Nb2/3)O-3-30 mol % PbTiO3 were investigated. It was observed that the size refinement down to similar to 90 nm impeded the phase transformation of the cubic phase formed in the course of sintering either into rhombohedral or into tetragonal one, and a series of phase transformation from cubic to rhombohedral and then to tetragonal phase took place as the average grain size increased from similar to 90 nm to similar to 5.7 mu m. This dependence of the crystal structure on the grain size was qualitatively explained in terms of the capillarity effect and the free volume at the grain boundaries exerting a negative hydrostatic pressure on the grains. With the change in crystal structure the typical ferroelectric behavior in dielectric properties evolved into that of a relaxor and finally into a paraelectric one. The overall changes in the dielectric behavior were interpreted on the basis of the size-driven phase transformation. An anomalous dielectric behavior, i.e., a relatively high dielectric constant over a wide range of temperature (30-330 degrees C), was observed at the average grain size of similar to 330 nm possibly due to a state of a single domain in a single grain, while below similar to 90 nm all the phases in the system practically transformed into the paraelectric cubic phase.close7

Development of Simultaneous Analytical Method for Imidazolinone Herbicides from Livestock Products by UHPLC-MSMS

A simultaneous analytical method, which used LC/MSMS for imidazolinone herbicides from livestock products (egg, milk, beef, pork, and chicken) for monitoring, was developed with a QuEChERS preparation. A weighed sample (5 g) in a 50 mL conical tube was added to 0.1 M potassium phosphate dibasic solution (5 mL) and shaken for 10 min. After shaking, 0.5 mL of 6 N HCl and 5 mL of acetonitrile were added, and this solution was shaken for 10 min. Additionally, QuEChERS extraction salts (original method, 4 g MgSO4, 1 g NaCl) were added to the sample in a 50 mL conical tube. The mixture was strongly shaken for 1 min and centrifuged at 3000× g for 10 min. The acetonitrile layer was purified with dSPE (150 mg MgSO4, 25 mg C18) and was centrifuged at 13,000× g for 5 min. The supernatant was filtered with a membrane filter (pore size: 0.2 μm) before analysis. The ME (%, matrix effect) range for almost all analytes was −6.56 to 7.11%. MLOD (method limit of detection) and MLOQ (method limit of quantitative) values were calculated by the S/N ratio. MLOQs were 0.01 mg/kg. The linear correlation coefficients (R2) were >0.99 with the range of 0.5~25 μg/kg for all of the imidazolinone herbicides. The recoveries (of imidazolinone herbicides) were in the range of 76.1~110.6% (0.01 mg/kg level), 89.2~97.1% (0.1 mg/kg level), and 94.4~104.4% (0.5 mg/kg level). These are within the validation criteria (to recover 70–120% with RSD <20%). The method demonstrated the simple, rapid, high throughput screening and quantitative analysis of imidazolinone herbicide residues for monitoring in livestock products

Longitudinal Study of Bone Height Change between Two Approaches for Sinus Floor Elevation

Background and Objectives: The purpose of this study is to assess the long-term maintenance of each approach of sinus elevation, the crestal approach and lateral approach, by comparing the radiographic results of each technique. Materials and Methods: In total, 103 patients who had undergone an implant procedure with either the crestal approach or lateral approach method applied to their maxillary molar edentulous area were included. Using orthopantomographs, the radiographic changes were consistently evaluated over 3 years after the procedure (immediately after procedure and 1 year, 2 years and 3 years after implant placement) Results: The radiographic evaluation after 3 years of implantation with sinus elevation showed a significant amount of bone formation (8.07 mm for crestal approach and 12.00 mm for lateral approach method). The largest amount of grafted height loss occurred during the 1 year, but the resorption was minimal (0.98 mm for crestal approach and 0.95 mm for lateral approach method) over the entire 3 years. Conclusions: Although the lateral approach showed more bone growth, the amount of bone resorption was similar to that of the crestal approach. Both methods showed the highest amount of bone resorption in the first year, and the amount of change thereafter was insignificant. It is judged that both methods can be used according to the situation to help implant placement

Synthesis of inorganic-organic two-dimensional CdSe slab-diamine quantum nets

Porous semiconductors attract great interest due to their unique structural characteristics of high surface area as well as their intrinsic optical and electronic properties. In this study, synthesis of inorganic-organic 2D CdSe slabs&amp;#8208;diaminooctane (DAO) porous quantum net structures is demonstrated. It is found that the hybrid 2D CdSe&amp;#8208;DAO lamellar structures are disintegrated into porous net structures, maintaining an ultrathin thickness of &amp;#8776;1 nm in CdSe slabs. Furthermore, the CdSe slabs in quantum nets show the highly shifted excitonic transition in the absorption spectrum, demonstrating their strongly confined electronic structures. The possible formation mechanism of this porous structure is investigated with the control experiments of the synthesis using n&amp;#8208;alkyldiamines with various hydrocarbon chain lengths and ligand exchange of DAO with oleylamine. It is suggested that a strong van der Waals interaction among long chain DAO may exert strong tensile stress on the CdSe slabs, eventually disintegrating slabs. The thermal decomposition of CdSe&amp;#8208;DAO quantum nets is further studied to form well&amp;#8208;defined CdSe nanorods. It is believed that the current CdSe&amp;#8208;DAO quantum nets will offer a new type of porous semiconductors nanostructures under a strong quantum&amp;#8208;confinement regime, which can be applied to various technological areas of catalysts, electronics, and optoelectronics

Enhanced Light Absorption and Efficient Carrier Collection in MoS2 Monolayers on Au Nanopillars

We fabricated hybrid nanostructures consisting of MoS2 monolayers and Au nanopillar (Au-NP) arrays. The surface morphology and Raman spectra showed that the MoS2 flakes transferred onto the Au-NPs were very flat and nonstrained. The Raman and photoluminescence intensities of MoS2/Au-NP were 3- and 20-fold larger than those of MoS2 flakes on a flat Au thin film, respectively. The finite-difference time-domain calculations showed that the Au-NPs significantly concentrated the incident light near their surfaces, leading to broadband absorption enhancement in the MoS2 flakes. Compared with a flat Au thin film, the Au-NPs enabled a 6-fold increase in the absorption in the MoS2 monolayer at a wavelength of 615 nm. The contact potential difference mapping showed that the electric potential at the MoS2/Au contact region was higher than that of the suspended MoS2 region by 85 mV. Such potential modulation enabled the Au-NPs to efficiently collect photogenerated electrons from the MoS2 flakes, as revealed by the uniform positive surface photovoltage signals throughout the MoS2 surface

Hemosuccus Pancreaticus in the Simple Mucinous Cyst of the Pancreas

Hemosuccus pancreaticus is an unusual gastrointestinal hemorrhage through the main pancreatic duct. We report a rare case of hemosuccus pancreaticus due to a simple mucinous cyst of the pancreas. A 52-year-old man who had been followed-up for a suspected branch duct intraductal papillary mucinous neoplasm (IPMN) visited the emergency room due to hematochezia. Endoscopy showed active bleeding from the ampulla. Computed tomography revealed hemorrhage in a 2.0-cm cystic mass in the pancreatic body. The patient was diagnosed with hemosuccus pancreaticus caused by bleeding into the main pancreatic duct from suspected IPMN. Elective laparoscopic distal pancreatectomy was performed. The histopathological diagnosis was a simple mucinous cyst with squamous metaplasia based upon the pathological finding involving the absence of ovarian-type stroma. In conclusion, it should be recognized that a pancreatic cyst including simple mucinous cyst may cause hemosuccus pancreaticus, and these cysts should be viewed as neoplastic and approached similarly as other mucinous pancreatic neoplasms

Status of Pesticide Usage on Golf Courses in Korea and Optimal Pesticide Usage Plan

Risks to human health and the environment owing to pesticide usage have arisen interest, increasing the demand for reducing pesticide consumption used on golf courses. However, standard guidelines or manuals for reducing pesticide usage on golf courses in Korea are lacking. Herein, the trends of pesticides on golf courses were investigated, and the optimal pesticide usage plan was proposed for continuous pesticide reduction. In 2019, there were 539 golf courses in Korea. With the increasing number of golf courses in 2010–2019, pesticide usage increased continuously. Fungicides accounted for more than half the pesticides used, followed by insecticides and herbicides. Except for golf courses that do not employ chemical pesticides, pesticide usage per unit area varied in the range of 0.02–65.81 kg ha−1 (average of 6.97 kg ha−1). In the US, best management practices and integrated pest management (IPM) have been stipulated and are operational in each state for pesticide management in golf courses, recognizing chemical pesticide usage to be the last approach for pest control and turf health maintenance. Considering that Korea globally ranks 10th in the number of golf facilities and courses, the establishment of IPM practices suitable for domestic conditions is essential