Bioconcentration and Metabolism of the New Herbicide Methiozolin in Ricefish (Oryzias latipes).

Methiozolin is a novel herbicide used to control annual bluegrass. It has low vapor pressure and high hydrophobicity, which could result in persistence in water and bioaccumulation. We measured the bioconcentration factors (BCFs) of methiozolin in ricefish (Oryzias latipes). Two radiolabels were used to quantify the parent compound and identify its metabolites. Ricefish were exposed to 2.0 and 20.0 ng/L methiozolin for 28 days in the uptake phase with a 96-h LC50 of 2.2 mg/L(95% confidence limit: 2.1-2.5 mg/L) and water solubility of 4.2 mg/L after 48 h was observed. On the basis of total radioactivity residues (TRRs), BCFss and BCFk values of 797.0-851.9 and 992.9-1077.4 were observed, respectively, while BCFss values for methiozolin were 251.9-257.5. Several minor metabolites with TRR < 3.4% were detected. Among them, 4-(2,6-difluorobenzyloxy-methyl)-3-hydroxy-3-methyl-1-(3-methylthiophen-2-yl)butan-1-one, 2,6-difluorobenzyl alcohol, and 4,5-dihydro-5-methyl-3-(3-methylthiophen-2-yl)isoxazol-5-yl)methanol were identified. Methiozolin is metabolized into numerous minor metabolites with potentially low bioaccumulation capacity in ricefish. These findings can facilitate risk assessments regarding methiozolin use, particularly its movements and final stages in aquatic environments.

Thermally Driven Out-of-Equilibrium Two-Impurity Kondo System.

The archetypal two-impurity Kondo problem in a serially coupled double quantum dot is investigated in the presence of a thermal bias θ. The slave-boson formulation is employed to obtain the nonlinear thermal and thermoelectrical responses. When the Kondo correlations prevail over the antiferromagnetic coupling J between dot spins, we demonstrate that the setup shows negative differential thermal conductance regions behaving as a thermal diode. In addition, we report a sign reversal of the thermoelectric current I(θ) controlled by t/Γ (t and Γ denote the interdot tunnel and reservoir-dot tunnel couplings, respectively) and θ. All these features are attributed to the fact that at large θ both Q(θ) (heat current) and I(θ) are suppressed regardless of the value of t/Γ because the double dot decouples at high thermal biases. Finally, for a finite J, we investigate how the Kondo-to-antiferromagnetic crossover is altered by θ.

Development and Validation of Predictive Model for Salmonella Growth in Unpasteurized Liquid Eggs.

Liquid egg products can be contaminated with Salmonella spp. during processing. A predictive model for the growth of Salmonella spp. in unpasteurized liquid eggs was developed and validated. Liquid whole egg, liquid yolk, and liquid egg white samples were prepared and inoculated with Salmonella mixture (approximately 3 Log CFU/mL) containing five serovars (S. Bareilly, S. Richmond, S. Typhimurium monophasic, S. Enteritidis, and S. Gallinarum). Salmonella growth data at isothermal temperatures (5, 10, 15, 20, 25, 30, 35, and 40°C) was collected by 960 h. The population of Salmonella in liquid whole egg and egg yolk increased at above 10°C, while Salmonella in egg white did not proliferate at all temperature. These results demonstrate that there is a difference in the growth of Salmonella depending on the types of liquid eggs (egg yolk, egg white, liquid whole egg) and storage temperature. To fit the growth data of Salmonella in liquid whole egg and egg yolk, Baranyi model was used as the primary model and the maximum growth rate and lag phase duration for each temperature were determined. A secondary model was developed with maximum growth rate as a function of temperature. The model performance measures, bias factor (B f , 0.96-0.99) and r2 (0.96-0.99) indicated good fit for both primary and secondary models. In conclusion, it is thought that the growth model can be used usefully to predict Salmonella spp. growth in various types of unpasteurized liquid eggs when those are exposed to various temperature and time conditions during the processing.

Distribution and Molecular Characterization of Campylobacter Species at Different Processing Stages in Two Poultry Processing Plants.

The present study analyzed the prevalence and molecular characterization of Campylobacter at different processing steps in poultry slaughterhouses to determine where contamination mainly occurs. A total of 1,040 samples were collected at four different stages (preprocessing cloacal swabs, postevisceration, postwashing, and postchilling) in two processing plants. Campylobacter was detected in 5.8% (15 of 260) of the cloacal swabs and in 13.3% (104 of 780) of the processing samples. In both plants, the sampling points with the greatest contamination rates were after evisceration (20.5% and 15.4% for plants A and B, respectively) and significantly decreased after chilling (p < 0.05, from 20.5% to 10.9%) in plant A and after washing (from 15.4% to 2.9%) in plants B. In the result, however, the reduction in Campylobacter contamination was achieved through the sequential processing procedures in both plants. Campylobacter loads (>103 colony-forming units [CFUs]/mL) also decreased from 41.7% at evisceration to 20.0% in final carcasses. The genetic relationships of isolates were analyzed by the automated repetitive sequence-based polymerase chain reaction (rep-PCR) system, and the rep-PCR banding pattern was found to be unrelated to the processing plants, species, sampling point, or sampling day. As the gap in the intervention efficacy remains between plant A and B despite several consistencies, a national program for monitoring critical processing stages in poultry processing plants is recommended for the successful exportation of Korean-processed white mini broiler meat.

Microbiological Evaluation of Pork and Chicken By-Products in South Korea.

In this study, we aimed to evaluate the microbiological risk of pork and chicken by-products by enumerating indicator bacteria (total aerobic bacteria, coliforms, and Escherichia coli) and identifying pathogens such as Campylobacter and Salmonella. The antibiotic resistance of pathogenic isolates was determined, and molecular subtyping was performed using automated repetitive sequence-based PCR (rep-PCR). Pork and chicken by-products were collected from 10 processing plants. The mean numbers of total aerobic bacteria, coliforms, and E. coli from 95 pork by-product samples and 64 chicken by-product samples were 5.1, 3.6, and 2.4 log CFU/g and 4.5, 3.0, and 1.8 log CFU/g, respectively. The numbers of indicator bacteria in the gastrointestinal tract (small intestine, large intestine, and gizzard) were significantly higher than those in other organs. Salmonella and Campylobacter species were detected in 3 and 5 of 95 pork by-product samples and in 6 and 3 of 64 chicken by-product samples, respectively. Four of 9 Salmonella isolates examined were resistant to eight antibiotics, and each of these resistant strains produced an extended-spectrum ß-lactamase. Most Campylobacter isolates were resistant to tetracycline (7 of 8 strains) and quinolones (7 of 8 strains). The similarity in rep-PCR patterns among Salmonella isolates was more closely associated with serotype than with the processing plant and type of meat. Conversely, the rep-PCR patterns of Campylobacter isolates were specific to the processing plant. Our findings could help agencies develop regulations for protection from foodborne bacterial infections arising from animal by-products.

Establishing Quantitative Standards for Residual Alkaline Phosphatase in Pasteurized Milk.

The alkaline phosphatase (ALP) assay is a rapid and convenient method for verifying milk pasteurization. Since colorimetric ALP assays rely on subjective visual assessments, their results are especially unreliable near the detection limits. In this study, we attempted to establish quantitative criteria for residual ALP in milk by using a more objective method based on spectrophotometric measurements. Raw milk was heat-treated for 0, 10, 20, 30, and 40 min and then subjected to ALP assays. The quantitative criteria for residual ALP in the milk was determined as 2 µg phenol/mL of milk, which is just above the ALP value of milk samples heat-treated for 30 min. These newly proposed methodology and criteria could facilitate the microbiological quality control of milk.

Incidence, Antimicrobial Resistance, and Molecular Characteristics of Nontyphoidal Salmonella Including Extended-Spectrum ß-Lactamase Producers in Retail Chicken Meat.

The present study was undertaken to determine the prevalence of Salmonella in 100 chicken carcass samples from five integrated broiler operation brands in Korea. Serotypes, antibiotic resistance patterns, extended-spectrum ß-lactamase (ESBL) genotype, and clonal divergence using multilocus sequence typing of the isolated strains were analyzed. A total of 42 chicken samples were contaminated with nontyphoidal Salmonella (NTS) isolates: 16 isolates (38%) were Salmonella Virchow, 9 (21%) were Salmonella Bareilly, and 8 (19%) were Salmonella Infantis. A multidrug resistance (MDR; resistant to more than three classes of antibiotics) phenotype was observed in 29% of the isolates, which were resistant to five or more classes of antibiotics. The dominant MDR type was resistance to classes of penicillin, cephalosporins, aminoglycosides, quinolones, and tetracyclines. All the MDR isolates were positive for ESBL producers, and all but one (with the CTX-M-1 genotype) had the CTX-M-15 genotype. Multilocus sequence typing of the isolates revealed ST16 as the dominant sequence type; Salmonella Virchow, Salmonella Infantis, and Salmonella Richmond were all ST16, indicating a close genetic relationship between these serovars. This is the first study in Korea showing the CTX-M-1 type of NTS and the prevalence of ESBL-producing strains among NTS isolated from retail chicken meat. Our findings suggest that MDR Salmonella contamination is widely prevalent in retail chicken meat, and consumption of inadequately cooked products could lead to dissemination of NTS, which is hazardous to human health.

Prevalence Analysis and Molecular Characterization of Salmonella at Different Processing Steps in Broiler Slaughter Plants in South Korea.

In this study, changes in the prevalence of Salmonella during the processing of broiler chicken carcasses were investigated. A total of 1040 fecal swabs and chicken carcasses samples were collected from 2 processing plants at the 4 stages of broiler processing, which included live birds in slaughter line, postevisceration/prewashing, postwashing/prechilling, and postchilling, respectively. The intraspecific biodiversity of the Salmonella isolates was determined using a DiversiLab automated repetitive sequence-based PCR (rep-PCR) system. In both plants, the prevalence of Salmonella increased considerably after evisceration (from 4.6% to 30.8%, P < 0.05) and decreased after washing (from 30.8% to 25.4%, P < 0.05). However, the chilling step had little effect on Salmonella prevalence (from 25.4% to 22.7%, P > 0.05). The most frequent Salmonella serovar in plant A was Infantis (35.8%), followed by Enteritidis (26.2%) and Montevideo (15.0%), while Montevideo (43.6%) and Enteritidis (35.9%) were most prevalent in plant B. A difference in the rep-PCR banding pattern was found to be related to the processing plant origin and serovar rather than sampling point or sampling day, although there were some exceptional strains.

Characterization of Escherichia coli-Producing Extended-Spectrum ß-Lactamase (ESBL) Isolated from Chicken Slaughterhouses in South Korea.

In South Korea, few reports have indicated the occurrence and characteristics of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli in food-producing animals, particularly in poultry slaughterhouses. In this study, we investigated the occurrence and antibiotic resistance of ESBL-producing E. coli from whole chicken carcasses (n=156) and fecal samples (n=39) of chickens obtained from 2 slaughterhouses. Each sample enriched in buffered peptone water was cultured on MacConkey agar with 2 mg/L cefotaxime and ESBL agar. ESBL production and antibiotic susceptibility were determined using the Trek Diagnostics system. The ESBL genotypes were determined by polymerase chain reaction (PCR) using the bla(SHV), bla(TEM), and bla(CTX-M) gene sequences. Subtyping using a repetitive sequence-based PCR system (DiversiLab™) and multilocus sequence typing (MLST) were used to assess the interspecific biodiversity of isolates. Sixty-two ESBL-producing E. coli isolates were obtained from 156 samples (39.7%). No bla(SHV) genes were detected in any of the isolates, whereas all contained the bla(TEM) gene. Twenty-five strains (40.3%) harbored the CTX-M group 1 gene. The most prevalent MLST sequence type (ST) was ST 93 (14.5%), followed by ST 117 (9.7%) and ST 2303 (8.1%). This study reveals a high occurrence and ß-lactams resistance rate of E. coli in fecal samples and whole chickens collected from slaughterhouses in South Korea.

Traceback investigation for Salmonella contamination at egg processing plants in South Korea: prevalence, antibiotic resistance, and epidemiological tracing by rep-PCR fingerprinting.

We conducted a survey of Salmonella from 8 egg-breaking plants and a farm to determine the prevalence and the source of the bacteria. The contents of 2400 shell eggs (20 eggs per pool), 75 pasteurized liquid egg products, and 120 unpasteurized liquid egg products from 8 egg-breaking plants in South Korea were examined. In liquid egg samples, 4 Salmonella-positive samples from 120 unpasteurized ones (3.3%) and 5 positive samples from 75 pasteurized ones (6.7%) were identified; no eggs were positive for Salmonella among shell egg samples. To trace the source of Salmonella, we revisited the 2 Salmonella-positive plants (plants A and C). We investigated the equipment and environments of the plants and a henhouse (farm A) that supplied shell eggs to plant A, and collected additional liquid eggs and shell eggs from plants A and C. All Salmonella isolates from plant A and the associated farm A, except for a single Typhimurium strain from farm A, were serotyped as Bareilly. Three serovars, including one Bareilly, four Tennessee, and one Richmond, were isolated from plant C. Most Salmonella isolates were susceptible to tested antibiotics. To identify differences between isolates, molecular subtyping by using the automated rep-PCR system was conducted. All Salmonella Bareilly (S. Bareilly) strains from plant A exhibited high similarity, indicating possible contamination by Salmonella strains from the henhouse A. Meanwhile, 2 S. Bareilly strains from plant C, one from liquid egg at the 1st visit and the other from container at the 2nd visit, exhibited identical antibiotic resistance and similar subtyping pattern, but clearly discriminated from the ones of plant A.

The prevalence of duck hepatitis A virus types 1 and 3 on Korean duck farms.

This study reports the prevalence of duck hepatitis A virus (DHAV) types 1 and 3 on Korean duck farms. By RT-nested PCR assays specific for DHAV-1 or DHAV-3, DHAV-1 was detected in 9 of 157 liver samples (5.7 %) from 2 of 30 farms (6.7 %), and DHAV-3 was positive in 104 of 157 liver samples (66.2 %) from 23 of 30 farms (76.7 %). Dual infections with DHAV-1 and DHAV-3 were detected in 23 of 157 samples (14.6 %) from 5 of 30 farms (16.7 %). The data indicate that DHAV-3 infections are prevalent and that DHAV-1 reemerged in Korea, resulting in dual infections on several farms. Our data will help to establish a vaccination policy against DHAV-1 and DHAV-3 in Korea.

A study on dispersion and rate of fat infiltration in the lumbar spine of patients with herniated nucleus polpusus.

[Purpose] This study investigated the relationship between herniated nucleus pulposus (HNP) and fat infiltration of muscles around the spine by measuring body mass index (BMI) and fat infiltration of the muscles around the spine. [Subjects and Methods] Subjects were 82 people, both men and women they were divided into two groups, a normal group and a patient group who were suffering from serious HNP between L4 and L5. Of the anthropometric measurement, and fat infiltration muscles by measuring the cross-sectional area from the center of the disc to the muscle around the spine and the cross-sectional area of fat infiltration. [Results] Fat infiltration rate of each lumbar layer in the normal group was different L34-L45 and L45-L5S1, but not between L23-L34. Fat infiltration in the muscle between the normal group and patients with HNP was different in the layers and the difference was greatest in the L5-S1 layer. [Conclusion] We performed correlation analysis of BMI and the total fat infiltration rate in each group to find the relationship between obesity and fat infiltration in the lumbar spine. Fat infiltration increased, and normal people or patients with chronic back pain are considered to be exposed to other diseases as fat infiltration in the lumbar spine increases.

In vivo absorption, distribution, excretion, and metabolism of a new herbicide, methiozolin, in rats following oral administration.

Methiozolin [5-(2,6-difluorobenzyl)oxymethyl-5-methyl-3-(3-methylthiophen-2-yl)-1,2-isoxazoline] is a new turf herbicide that controls annual bluegrass in various cool- and warm-season turfgrasses. The present study is the first report elucidating absorption, tissue distribution, excretion, and metabolism of methiozolin in rats. The pharmacokinetic parameters in the blood were observed as follows: t(max) = 6 h, C(max) = 168.7 µg equiv/mL, t(½) = 49.4 h, AUC120 = 9921.5 µg equiv·h/mL, and clearance = 39.2 mL/h/kg. Those parameters and the depletion curve for ¹4C in the plasma were very similar to those in the blood. Total excretion through urine and feces was 24.3 and 68.9%, respectively, during 120 h after administration; however, there was no excretion through expired air. The radioactivity excreted through bile was 40.1% of that administered. Excreted radioactivity peaked between 24 and 48 h, showing 51.0% of total excretion within 48 h. The orally administered ¹4C distributed across various tissues within 12 h after administration, showing 14.0% of the dosed, and was eliminated from all tissues without accumulation. Numerous minor metabolites (<4% of the dosed) in urine and fecal extract were detected within 72 h, and two of those were identified. The identified metabolites were Met-1 (glucuronic acid conjugate), 6-[5-(5-((2,6-difluorobenzyloxy)methyl)-4,5-dihydro-5-methylisoxazol-3-yl)-4-methylthiophen-2-yloxy]-tetrahydro-3,4,5-trihydroxy-2H-pyran-2-carboxylic acid, and Met-2, [2-(5-((2,6-difluorobenzyloxy)methyl)-4,5-dihydro-5-methylisoxazol-3-yl)thiophen-3-yl]methanol. Conclusively, methiozolin was shown to be readily absorbed in the gastrointestinal tract, distributed throughout the tissues within 12 h, metabolized extensively, and eliminated through urine and feces mostly within 48 h, without tissue accumulation.

Soil metabolism of [14C]methiozolin under aerobic and anaerobic flooded conditions.

Methiozolin is a new turf herbicide controlling annual bluegrass in various cool- and warm-season turfgrasses. This study was conducted to investigate the fate of methiozolin in soil under aerobic and anaerobic flooded conditions using two radiolabeled tracers, [benzyl-(14)C]- and [isoxazole-(14)C]methiozolin. The mass balance of applied radioactivity ranged from 91.7 to 104.5% in both soil conditions. In the soil under the aerobic condition, [(14)C]methiozolin degraded with time to remain by 17.9 and 15.9% of the applied in soil at 120 days after treatment (DAT). [(14)C]Carbon dioxide and the nonextractable radioactivity increased as the soil aged to reach up to 41.5 and 35.7% for [benzyl-(14)C]methiozolin at 120 DAT, respectively, but 36.1 and 39.8% for [isoxazole-(14)C]methiozolin, respectively, during the same period. The nonextractable residue was associated more with humin and fulvic acid fractions under the aerobic condition. No significant volatile products or metabolites were detected during this study. The half-life of [(14)C]methiozolin was approximately 49 days in the soil under the aerobic condition; however, it could not be estimated in the soil under the anaerobic flooded condition because [(14)C]methiozolin degradation was limited. On the basis of these results, methiozolin is considered to undergo fast degradation by aerobic microbes, but not by anaerobic microbes in soil.

Noise and fluctuation relations of a spin diode.

: We consider fluctuation relations between the transport coefficients of a spintronic system where magnetic interactions play a crucial role. We investigate a prototypical spintronic device - a spin-diode - which consists of an interacting resonant level coupled to two ferromagnetic electrodes. We thereby obtain the cumulant generating function for the spin transport in the sequential tunnelling regime. We demonstrate the fulfilment of the nonlinear fluctuation relations when up and down spin currents are correlated in the presence of both spin-flip processes and external magnetic fields.

Transport measurement of Andreev bound states in a Kondo-correlated quantum dot.

We report nonequilibrium transport measurements of gate-tunable Andreev bound states in a carbon nanotube quantum dot coupled to two superconducting leads. In particular, we observe clear features of two types of Kondo ridges, which can be understood in terms of the interplay between the Kondo effect and superconductivity. In the first type (type I), the coupling is strong and the Kondo effect is dominant. Levels of the Andreev bound states display anticrossing in the middle of the ridge. On the other hand, crossing of the two Andreev bound states is shown in the second type (type II) together with the 0-π transition of the Josephson junction. Our scenario is well understood in terms of only a single dimensionless parameter, k(B)T(K)(min)/Δ, where T(K)(min) and Δ are the minimum Kondo temperature of a ridge and the superconducting order parameter, respectively. Our observation is consistent with measurements of the critical current, and is supported by numerical renormalization group calculations.

Fluctuation relations for spintronics.

Fluctuation relations are derived in systems where the spin degree of freedom and magnetic interactions play a crucial role. The form of the nonequilibrium fluctuation theorems relies on the assumption of a local balance condition. We demonstrate that in some cases the presence of magnetic interactions violates this condition. Nevertheless, fluctuation relations can be obtained from the microreversibility principle sustained only at equilibrium as a symmetry of the cumulant generating function for spin currents. We illustrate the spintronic fluctuation relations for a quantum dot coupled to partially polarized helical edge states.

Tunable Kondo effect in a double quantum dot coupled to ferromagnetic contacts.

We investigate the effects induced by ferromagnetic contacts attached to a serial double quantum dot. Spin polarization generates effective magnetic fields and suppresses the Kondo effect in each dot. The superexchange interaction J(AFM), tuned by the interdot tunneling rate t, can be used to compensate the effective fields and restore the Kondo resonance when the contact polarizations are aligned. As a consequence, the direction of the spin conductance can be controlled and even reversed using electrostatic gates alone. Our results demonstrate a new approach for controlling spin-dependent transport in carbon nanotube double dot devices.

Josephson current in carbon nanotubes with spin-orbit interaction.

We demonstrate that curvature-induced spin-orbit coupling induces a 0-π transition in the Josephson current through a carbon nanotube quantum dot coupled to superconducting leads. In the noninteracting regime, the transition can be tuned by applying a parallel magnetic field near the critical field where orbital states become degenerate. Moreover, the interplay between charging and spin-orbit effects in the Coulomb blockade and cotunneling regimes leads to a rich phase diagram with well-defined (analytical) boundaries in parameter space. Finally, the 0 phase always prevails in the Kondo regime. Our calculations are relevant in view of recent experimental advances in transport through ultraclean carbon nanotubes.