Genotypic characterization of Staphylococcus chromogenes and Staphylococcus simulans from Swedish cases of bovine subclinical mastitis.

Staphylococcus chromogenes and Staphylococcus simulans are commonly found in intramammary infections (IMI) associated with bovine subclinical mastitis, but little is known about genotypic variation and relatedness within species. This includes knowledge about genes encoding antimicrobial resistance (AMR) and potential virulence factors (pVF). The aim of this study was therefore to investigate these aspects by whole-genome sequencing of milk isolates from Swedish dairy cows with subclinical mastitis in an observational study. We also wanted to study if specific genotypes were associated with persistent IMI and the inflammatory response at udder quarter level. In total, 105 and 118 isolates of S. chromogenes and S. simulans, respectively, were included. Isolates were characterized using a 7-locus multilocus sequence typing (7-MLST), core genome analysis and in-silico analysis of AMR and pVF genes. Forty-seven sequence types (ST) and 7 core genome clusters of S. chromogenes were identified, and the most common ST were ST-6 and ST-109, both belonging to cluster VII. A 7-locus MLST scheme for S. simulans was not available, but 3 core genome clusters and 5 subclusters were described. Overall, substantial variation in ST and clusters among cows and herds were found in both species. Some ST of S. chromogenes were found in several herds, indicating spread between herds. Moreover, within-herd spread of the same genotype was observed for both species. Only a few AMR genes [blaZ, strpS194, vga(A)] were detected in a limited number of isolates, with the exception of blaZ coding for ß-lactamase, which was identified in 22% of the isolates of S. chromogenes with ST-19, ST-102, and ST-103 more commonly carrying this gene compared with other ST. However, the blaZ gene was not identified in S. simulans. The average total number of pVF detected per isolate was similar in S. chromogenes (n = 30) and S. simulans (n = 33), but some variation in total numbers and presence of specific pVF or functional groups of pVF, was shown between ST/clusters within species. Differences in inflammatory response and potentially in persistent IMI at udder quarter level were found between S. chromogenes subtypes but not between S. simulans subtypes. In conclusion, the results from the present study generates new insight into the epidemiology of bovine S. chromogenes and S. simulans IMI, which can have implications for future prevention and antimicrobial treatment of infections related to these species.

Spectroscopic speciation of aqueous Am(iii)-oxalate complexes.

Transportation of actinides through the geosphere is facilitated by complexation with organic ligands dissolved in groundwater. Carboxylic groups can interact directly with actinide ions and are found among the most abundant organic ligands in alkaline aquatic systems like underground water. In this study, the complexation of organic carboxylic groups with Am(iii) was investigated by monitoring the interactions of Am(iii) with oxalate (Ox), the simplest dicarboxylate ligand, in solution. UV-Vis spectrophotometry coupled with a liquid waveguide capillary cell (100 cm optical path-length) and time-resolved laser fluorescence spectroscopy were employed for quantitative detection of the respective Am(iii)-Ox species. Increasing the Ox concentration caused significant spectral changes, i.e., red-shifts in both the absorption and luminescence maxima with increased molar absorption coefficients, enhanced luminescence intensities, and prolonged luminescence lifetimes. Individual spectra of AmOx+(aq), Am(Ox)2-(aq), and Am(Ox)33-(aq) were resolved by deconvolution of the absorption spectra, with apparent formation constants of log ß1,1 = 5.34 ± 0.05, log ß1,2 = 9.14 ± 0.18, and log ß1,3 = 11.49 ± 0.30, respectively, in I = 0.1 M NaClO4 and 0-30 mM Na2Ox. The absorption and luminescence spectral changes suggest bidentate complexation of Ox with Am(iii) via inner-sphere interactions. The geometry of the Am(iii)-Ox complexes was optimized by density functional theory, where the bonding characteristics were in good agreement with the experimental results. Thorough spectroscopic characterization enabled speciation of the Am(iii)-Ox complexes and determination of their formation constants. This spectroscopic approach is generally applicable in the investigation of molecular interactions between Am(iii) and various ligands in aqueous solution.

Bragg Coherent Diffractive Imaging of Zinc Oxide Acoustic Phonons at Picosecond Timescales.

Mesoscale thermal transport is of fundamental interest and practical importance in materials such as thermoelectrics. Coherent lattice vibrations (acoustic phonons) govern thermal transport in crystalline solids and are affected by the shape, size, and defect density in nanoscale materials. The advent of hard x-ray free electron lasers (XFELs) capable of producing ultrafast x-ray pulses has significantly impacted the understanding of acoustic phonons by enabling their direct study with x-rays. However, previous studies have reported ensemble-averaged results that cannot distinguish the impact of mesoscale heterogeneity on the phonon dynamics. Here we use Bragg coherent diffractive imaging (BCDI) to resolve the 4D evolution of the acoustic phonons in a single zinc oxide rod with a spatial resolution of 50 nm and a temporal resolution of 25 picoseconds. We observe homogeneous (lattice breathing/rotation) and inhomogeneous (shear) acoustic phonon modes, which are compared to finite element simulations. We investigate the possibility of changing phonon dynamics by altering the crystal through acid etching. We find that the acid heterogeneously dissolves the crystal volume, which will significantly impact the phonon dynamics. In general, our results represent the first step towards understanding the effect of structural properties at the individual crystal level on phonon dynamics.

Stability Limits and Defect Dynamics in Ag Nanoparticles Probed by Bragg Coherent Diffractive Imaging.

Dissolution is critical to nanomaterial stability, especially for partially dealloyed nanoparticle catalysts. Unfortunately, highly active catalysts are often not stable in their reactive environments, preventing widespread application. Thus, focusing on the structure-stability relationship at the nanoscale is crucial and will likely play an important role in meeting grand challenges. Recent advances in imaging capability have come from electron, X-ray, and other techniques but tend to be limited to specific sample environments and/or two-dimensional images. Here, we report investigations into the defect-stability relationship of silver nanoparticles to voltage-induced electrochemical dissolution imaged in situ in three-dimensional detail by Bragg coherent diffractive imaging. We first determine the average dissolution kinetics by stationary probe rotating disk electrode in combination with inductively coupled plasma mass spectrometry, which allows in situ measurement of Ag+ ion formation. We then observe the dissolution and redeposition processes in single nanocrystals, providing unique insight about the role of surface strain, defects, and their coupling to the dissolution chemistry. The methods developed and the knowledge gained go well beyond a "simple" silver electrochemistry and are applicable to all electrocatalytic reactions where functional links between activity and stability are controlled by structure and defect dynamics.

False-positive cytopathology results for papillary thyroid carcinoma: A trap for thyroid surgeons.

OBJECTIVES: Current preoperative diagnosis of thyroid nodules remains imperfect despite recent advances in cytopathology and molecular diagnostics. False positivity in preoperative fine-needle aspiration cytology (FNAC) may lead to overtreatment of patients, including total thyroidectomy, and sometimes to lawsuits for misdiagnosis and malpractice. In this study, we analysed clinical characteristics and pathologic findings in patients with false positivity for papillary thyroid carcinoma (PTC) in FNAC. METHODS: We retrospectively reviewed permanent pathology results from 3788 patients who underwent thyroid surgery. Among them, 48 patients had lesions that were deemed suspicious or positive (Bethesda class V or VI) for PTC in preoperative FNAC. We reviewed clinic-pathologic data, radiologic findings and surgical planning in these patients. RESULTS: The prevalence of pathologic thyroiditis was significantly higher among patients with false-positive FNAC results than in those with confirmed PTC (54.2% vs 9.2%, P<.001). The analysis of the permanent pathology reports showed that 26 patients had chronic lymphocytic thyroiditis and 22 patients had no evidence of thyroiditis. Among the patients without pathologic thyroiditis, 19 patients (86.4%) had nodular hyperplasia and three (13.6%) had follicular adenoma, while among the patients with pathologic thyroiditis, seven (26.9%) had no nodule, 14 (53.8%) had nodular hyperplasia, two (7.7%) had hyalinized nodules, two (7.7%) had follicular adenoma and one (3.8%) had a hyalinizing trabecular tumour. In 42 patients, the extent of surgery (total thyroidectomy or hemithyroidectomy) was to be determined according to the intra-operative frozen section biopsy results. Among them, four (10.5%) had inconclusive frozen section results, and 38 (90.5%) had benign results on frozen section. CONCLUSIONS: Patient counselling about the possibility of false positivity is still important. And the presence of thyroiditis might create confusion in the interpretation of cytopathologic results.

Three-dimensional imaging of dislocation dynamics during the hydriding phase transformation.

Crystallographic imperfections significantly alter material properties and their response to external stimuli, including solute-induced phase transformations. Despite recent progress in imaging defects using electron and X-ray techniques, in situ three-dimensional imaging of defect dynamics remains challenging. Here, we use Bragg coherent diffractive imaging to image defects during the hydriding phase transformation of palladium nanocrystals. During constant-pressure experiments we observe that the phase transformation begins after dislocation nucleation close to the phase boundary in particles larger than 300 nm. The three-dimensional phase morphology suggests that the hydrogen-rich phase is more similar to a spherical cap on the hydrogen-poor phase than to the core-shell model commonly assumed. We substantiate this using three-dimensional phase field modelling, demonstrating how phase morphology affects the critical size for dislocation nucleation. Our results reveal how particle size and phase morphology affects transformations in the PdH system.

Three Dimensional Variable-Wavelength X-Ray Bragg Coherent Diffraction Imaging.

We present and demonstrate a formalism by which three-dimensional (3D) Bragg x-ray coherent diffraction imaging (BCDI) can be implemented without moving the sample by scanning the energy of the incident x-ray beam. This capability is made possible by introducing a 3D Fourier transform that accounts for x-ray wavelength variability. We demonstrate the approach by inverting coherent Bragg diffraction patterns from a gold nanocrystal measured with an x-ray energy scan. Variable-wavelength BCDI will expand the breadth of feasible in situ 3D strain imaging experiments towards more diverse materials environments, especially where sample manipulation is difficult.

Factors associated with increasing campylobacteriosis incidence in Michigan, 2004-2013.

This study was conducted to examine the incidence trend of campylobacteriosis in Michigan over a 10-year period and to investigate risk factors and clinical outcomes associated with infection. Campylobacter case data from 2004 to 2013 was obtained from the Michigan Disease Surveillance System. We conducted statistical and spatial analyses to examine trends and identify factors linked to campylobacteriosis as well as ecological associations using animal density data from the National Agricultural Statistics Service. An increasing trend of Campylobacter incidence and hospitalization was observed, which was linked to specific age groups and rural residence. Cases reporting ruminant contact and well water as the primary drinking source had a higher risk of campylobacteriosis, while higher cattle density was associated with an increased risk at the county level. Additional studies are needed to identify age-specific risk factors and examine prevalence and transmission dynamics in ruminants and the environment to aid in the development of more effective preventive strategies.

Time-resolved laser fluorescence spectroscopy of UO2(CO3)3(4-).

The objective of the present study is to examine the luminescence characteristics of UO2(CO3)3(4-) in detail using time-resolved laser fluorescence spectroscopy. The peak wavelengths and lifetime of UO2(CO3)3(4-) were determined at room temperature using the two excitation laser wavelengths of 266 and 448 nm. The peak wavelengths in the luminescence spectrum exhibited hypsochromic shifts compared with those of UO2(2+). The lifetime determined from several samples containing various uranium concentrations was 8.9 ± 0.8 ns. Explanations for the hindrance to the observation of the luminescence spectrum of UO2(CO3)3(4-) in previous investigations are discussed. The representative experimental parameters, which might interrupt the measurement of weak luminescence, are the insertion delay time of the detection device, the overlapped luminescence of the background materials and the primary inner filter effect in the sample solution.

The Korean version of the University of Washington Quality of Life Questionnaire for Patients with head and neck cancer, and its use in an initial validation study of 56 patients.

The University of Washington Quality of Life (UW-QOL) questionnaire is often used to assess health-related quality of life (HRQOL) of head and neck cancer patients. The aim of this study was to translate the UW-QOL version 4 into the Korean language and to carry out an initial validation study. A recognized methodology for translation of questionnaires was used. The validation study used the final Korean version between March and September 2009. Adult patients were recruited, with a confirmed diagnosis of head and neck cancer, therapy completed and disease-free for at least 1 year. The UW-QOL was successfully translated into Korean. 56 patients completed Korean versions of UW-QOL, the Beck Depression Inventory and the World Health Organization Quality of Life-BREF and various expected correlations were confirmed first between the two UW-QOL subscales (Spearman 0.54 p<0.001) and then of these subscales with the other concurrent measures. Lower (worse) UW-QOL scores were seen for later stage patients in all 12 domains. The Korean version of UW-QOL is ready for use in the assessment of HRQOL for Korean patients. Validation work needs to be continued to further establish psychometric properties of the questionnaire for use in this population.

Evaluation of wastewater effluents for soil aquifer treatment in South Korea.

Soil batch and column experiments were performed to characterize the wastewater effluents from seven different wastewater treatment plants in the Jonnam province, South Korea, with the purpose of evaluating the effluents for possible application of a soil aquifer treatment (SAT) in Korea. Batch experiments were conducted to measure the biodegradable dissolved organic carbon (BDOC) while 1 m soil columns, for simulating SAT, were employed to further analyze dissolved organic carbon (DOC) removal. The soils were collected from a river bottom in Jonnam. The BDOC fractions and the residual DOC concentrations for the effluents ranged from 19.3 to 59.9% and from 1.0 to 7.5 mg/L, respectively, depending on the reaction time. Applying the tentative criteria based on the data obtained for the BDOC and residual DOC, three effluents, from Gwangju, Hwasoon, and Jangsung, were found to be the most suitable for SAT applications. It was also concluded that the site characteristics should be also considered with regard to the retention time when evaluating the feasibility of SAT application in a certain region.

In vitro blastocyst formation of human oocytes obtained from unstimulated and stimulated cycles after vitrification at various maturational stages.

OBJECTIVE: To evaluate the developmental competence and chromosomal normality of oocytes vitrified at various times after maturation culture. DESIGN: In vitro model study. SETTING: A university-affiliated hospital. PATIENT(S): Unstimulated women who underwent cesarean section or oophorectomy and infertile women who underwent a long protocol of GnRH stimulation. INTERVENTION(S): Retrieved oocytes were vitrified at 0 or 48 hours after culture in unstimulated cycles and at 0, 8-15, or 24-28 hours after culture in stimulated cycles. MAIN OUTCOME MEASURE(S): Postthaw morphologic normality, maturation, fertilization, cleavage, blastocyst formation, and chromosome number. RESULT(S): In the 53 oocytes that were obtained from unstimulated cycles, no statistically significant differences were found in rates of morphologic normality (range, 56%-63%) or fertilization (range, 31%-37%) according to the time of vitrification. In the 50 oocytes that were obtained from stimulated cycles, more of those that were vitrified at 24-28 hours were morphologically normal than those that were vitrified at 0 or 8-15 hours. Regardless of these differences, high cleavage rates (83%-100%) were obtained that did not differ significantly among the treatment groups. In both cycles, 20%-43% of cleaved oocytes developed to the blastocyst stage by 6 days after IVF. All the karyotyped blastocysts, three from unstimulated cycles and four from stimulated cycles, had a normal number of chromosomes. CONCLUSION(S): Vitrified and thawed oocytes from unstimulated or stimulated cycles developed to the blastocyst stage, regardless of when vitrification occurred; the number of chromosomes in the blastocysts was normal.

[Minus strand of hepatitis C virus RNA in hepatocellular carcinoma and pericancerous nontumor liver tissue].

In five hepatocellular carcinoma patients with type C chronic live disease (four men and one woman), the minus strand of hepatitis C virus RNA was examined by nested polymerase chain reaction (PCR), The plus strand RNA was detected in the sera and pericancerous nontumor liver tissue, but the minus strand RNA was only detected in the liver (except 2 hepatocellular carcinoma). Because hepatitis C virus has a single-strand RNA of positive polarity, a minus-strand RNA is expected to be found in hepatitis C virus replicating tissues as a template for the synthesis of genome RNA. The detection of the minus strand of hepatitis C virus suggested that this virus may not only function as initiator of hepatocarcinogenesis, but may also as a promoter of carcinogenesis.

Poly(vinyl alcohol) hydrogels as soft contact lens material.

A new type of soft contact lens was developed from the poly(vinyl alcohol) (PVA) hydrogel prepared by a low temperature crystallization technique using a water-dimethyl sulfoxide mixed solvent. The PVA contact lens materials had a water content of 78% and a tensile strength of 50 kg/cm2, five times as strong as that of commercial poly(2-hydroxyethyl methacrylate) soft contact lens. The amount of proteins adsorbed to the PVA soft hydrogel material was half to one thirtieth of that of conventional soft contact lenses. Histological and scanning electron microscopic observation of rabbit eyes which had worn the PVA soft contact lens for 12 weeks showed no difference in corneal epithelium and cell arrangement in the corneal epithelium from the non-wearing eyes.

[A polyvinyl alcohol (PVA) hydrogel as a soft contact lens material].

A transparent polyvinyl alcohol (PVA) hydrogel was prepared from a PVA solution in a mixed solvent consisting of water and a water miscible organic solvent by cooling. The physical properties were evaluated in comparison with commercially available soft contact lens materials, such as polyhydroxyethyl methacrylate (PHEMA) and copolymers of methyl methacrylate (MMA) and N-vinyl pyrrolidone (VP). The PVA hydrogel showed higher tensile strength and elongation at break than the other materials, while it had high water content and oxygen permeability the latter being comparable to those of PMMA/VP copolymers. The protein adsorption of the PVA hydrogel was much less than those of the other materials. The PVA hydrogel soft contact lenses were applied on rabbit eyes for 12 weeks. The influence on the cornea was studied by biomicroscopy, ultrasonic corneal pachymetry and histopathological examination. These examinations revealed no abnormal findings in the cornea. These results suggest that the PVA hydrogel may be promising as a new soft contact lens material.

Evaluation of polyvinyl alcohol hydrogel as a soft contact lens material.

We prepared a transparent polyvinyl alcohol (PVA) hydrogel from a PVA solution in a mixed solvent consisting of water and a water-miscible organic solvent by cooling. The physical properties of the hydrogel were evaluated in various mixed solvents and compared with those of commercially available soft contact lens materials, such as polyhydroxyethyl methacrylate (PHEMA) and copolymers of methylmethycrylate (MMA) and N-vinyl pyrrolidone (N-VP). The PVA hydrogel showed higher tensile strength and elongation before breaking than did the other materials. Also, the PVA hydrogel was comparable in its high water content and its oxygen permeability with the MMA/VP copolymers. The protein adsorption of the PVA hydrogel was much lower than that of the other materials. Soft contact lenses of PVA hydrogel were applied to rabbit eyes for 12 weeks. The effects of the lenses on the cornea were studied by biomicroscopy, ultrasonic pachymetry, and histopathologic examination. No abnormal findings were noted, suggesting that the PVA hydrogel may be promising as a new material for use in soft contact lenses.