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The spectral detection of weak frequency band signals poses a serious problem in many applications, especially when the target is within a certain frequency band under low signal-to-noise ratio (SNR) conditions. A kind of novel technique based on the pre-whitening scale transformation of stochastic resonance (SR) in a symmetric bistable system in a parallel configuration is proposed to solve the problem. Firstly, pre-whitening can ensure the Gaussian distribution of the receiving signal fits the requirements for SR processing. Secondly, scale transformation can help to effectively utilize the properties of a weak signal, especially under a low-frequency band. Thirdly, the SR in a symmetric bistable system in a parallel configuration can try to smoothly reduce the variances in the clutter and additive noise. Fourthly, by subtracting the steady state response of the SR in the selected symmetric bistable system from the parallel output, the spectral detection of a weak signal can be realized successfully. Experiment results based on actual sea clutter radar data guarantee the effectiveness and applicability of the proposed symmetric bistable PSR processing approach. [ABSTRACT FROM AUTHOR]

Terbium aluminum garnet (Tb3Al5O12, TAG) ceramics have become a promising magneto‐optical material owing to the outstanding comprehensive performance, including the magneto‐optical, thermal, and mechanical properties. Fine‐grained TAG ceramics with high optical quality and mechanical properties have attracted much attention. In this study, TAG ceramics with fine grains and high optical quality are fabricated successfully by a two‐step sintering method from co‐precipitated nano‐powders. After pre‐sintered at 1525°C in vacuum and hot isostatic pressed at 1600°C, the in‐line transmittance of TAG ceramics reaches 81.8% at 1064 nm, and the average grain size is 7.1 μm. The Verdet constant of TAG ceramics is −179.6 ± 4.8 rad T−1 m−1 at 633 nm and −52.1 ± 1.9 rad T−1 m−1 at 1064 nm, higher than that of commercial Tb3Ga5O12 crystals. The thermal conductivity of TAG ceramics is determined from 25 to 450°C, and the result is 5.12 W m−1 K−1 at 25°C and 3.61 W m−1 K−1 at 450°C. A comparison of mechanical properties between large‐ and fine‐grained TAG ceramics fabricated under different conditions is conducted. The fine‐grained TAG ceramics possess a bending strength of 226.3 ± 16.4 MPa, which is 9.7% higher than that of the large‐grained ceramics. These results indicate that reducing the grain size on the premise of high optical quality helps improve the comprehensive performance of TAG ceramics. [ABSTRACT FROM AUTHOR]

Ready‐to‐eat (RTE) foods are widely marketed in China and are important components of everyday diet. In this study, a total of 2000 RTE food samples were analyzed, 252 (12.60%) of which were positive for Enterobacteriaceae, and 48 were identified as containing extended‐spectrum β‐lactamase (ESBL)‐producing Escherichia coli isolates. Furthermore, the antimicrobial resistance patterns of these isolates to 14 antimicrobial agents revealed that most isolates were resistant to aminoglycosides and β‐lactam antibiotics. The TEM‐type gene was prevalent in our isolates (79.17%). The isolates (n = 48) were classified into three clusters based on the ERIC‐PCR results. Forty‐eight sequence types were found without duplicates, revealing genetic variation and relatedness among isolates. Thus, the results demonstrated the presence of ESBL‐producing Enterobacteriaceae in Chinese RTE foods. The results of this study provide insights into the spread of antibiotic‐resistant strains and improve understanding of microbial risks. [ABSTRACT FROM AUTHOR]

Macadamia oil cake (MOC) is a type of macadamia nut by‐product, that is extremely rich in amino acids and has beneficial health effects. It lowers blood lipid levels and regulates the intestinal microbiota. MOC effectively attenuated total cholesterol (TC), triglyceride (TG), low‐density lipoprotein cholesterol (LDL‐C), and high‐density lipoprotein cholesterol (HDL‐C) levels in model rats. Depending on the morphology of the colon, MOC can effectively attenuate damage to the tissue structure. The 16S rDNA gene of the rat intestinal microbiota was sequenced using Illumina PE250 high‐throughput sequencing technology, and the changes in the intestinal microbiota in each group are discussed. Supplementing MOC at different doses significantly increased the microbiota of Dorea, Erysipelotrichaceae, Stercoris, etc. in the intestinal tracts of rats fed a high‐fat diet. Therefore, MOC can be included in lipid healthy dietary patterns to lower lipid characteristics and restructure the intestinal microbiota. Future clinical trials are required to determine the therapeutic effects and mechanisms of hypolipidemia. [ABSTRACT FROM AUTHOR]

To suppress heat effects in a high‐power laser system, it has been proposed to use a few composite laser gain media to improve the heat management ability. The surface‐gain structure has the advantages of both slab and thin‐disk configurations, which has huge potential in high‐power laser. For the first time, novel composite laser ceramics with surface‐gain structure have been fabricated by tape casting and sintering technology. The in‐line transmittances of surface‐gain ceramics in 1100 and 400 nm are 83.5% and 79.1%, respectively. According to the laser ablation–coupled plasma mass spectrometry, the diffusion distance of Yb3+ is about 150 µm. The laser experiment yields a low repetition rate pulse of 1.9 J with a pump absorption energy of 11 J and an optical‐to‐optical conversion efficiency of 17.2%. [ABSTRACT FROM AUTHOR]

In order to fully pump and smoothen the temperature gradient of the gain medium, multistage gradient doping Yb:YAG laser ceramics were designed. The composite green bodies were fabricated by tape casting, and multistage gradient doping Yb:YAG ceramics with high optical quality were prepared by vacuum sintering and hot isostatic pressing. For samples pre‐sintered at 1740°C for 30 h and then HIP‐ed at 1700°C for 3 h in argon at 200 MPa, the in‐line transmission values at 1100 nm of YAG, 0.6 at.%Yb:YAG, and 1.5 at.%Yb:YAG ceramics were found to be 83.9%, 84.1%, and 83.3%, respectively. Finally, the 940 nm laser diode was used as the pump source to realize the 1030 nm laser output of multistage gradient doping Yb:YAG ceramic slab with a total energy of 3.43 J. The corresponding optical‐to‐optical conversion and slope efficiencies were 30% and 45%. [ABSTRACT FROM AUTHOR]

In recent years, transparent terbium aluminum garnet (TAG) ceramics have attracted much attention for use in high-power Faraday isolators. Fine-grained ceramics usually possess better mechanical properties and accordingly better service performance. In this work, transparent TAG ceramics with fine grains were prepared using a two-step sintering procedure based on the low-temperature sintering process to suppress grain growth. The composition of TAG precursor and powders calcined at different temperatures was studied in detail. The microstructure and relative density of air pre-sintered TAG ceramics were studied to meet the requirements of hot isostatic pressing (HIP) post-treatment. Driven by the low pre-sintering temperature in air, the average grain sizes of the obtained TAG ceramics after HIP treatment are about 2.9–5.3 μm. The TAG ceramics (1.2 mm thick) pre-sintered at 1450 °C with HIP post-treatment at 1550 °C for 3 h under a 176 MPa Ar atmosphere possess the highest in-line transmittance of 80.3% at 1064 nm. The Verdet constant of the TAG ceramics at 632.8 nm is −180.5 rad·T−1·m−1 at room temperature, which is about 1.3 times larger than that of the commercial Tb3Ga5O12 single crystals. [ABSTRACT FROM AUTHOR]

Transparent terbium aluminum garnet (TAG)‐based ceramics were fabricated by vacuum pre‐sintering and hot isostatic pressing (HIP) posttreatment from the co‐precipitated TAG powders with different stoichiometric ratios. After component optimization, the transparent ceramics with TAG single‐phase and attractive optical quality were obtained. The in‐line transmittance of optimal Tb(1+x)3(Al0.996255Si0.003745)5O12.0093625+3x/2 (x = −.004, −.002) ceramics (1.7‐mm thick) pre‐sintered at 1700°C for 20 h with HIP posttreatment at 1700°C for 3 h under 176‐MPa Ar reaches 82.6% at the wavelength of 1064 nm. With increasing terbium components, the secondary phase TAP appears in ceramics, which significantly degrades the optical quality of TAG‐based ceramics. The Verdet constant of the TAG‐based ceramics at 632.8 nm is about −181 rad T−1 m−1 at room temperature, which is about 33% higher than that of the TGG single crystals (−134 rad T−1 m−1). [ABSTRACT FROM AUTHOR]

Due to their potential application in spintronic devices, two-dimensional (2D) ferromagnetic materials are highly desired. We used first-principles calculations and Monte Carlo simulations to investigate the electronic structure and magnetic characteristics of the MnOCl2 monolayers. We discovered two stable monolayer structures, Pmna-MnOCl2 and Pmmn-MnOCl2. Our findings show that the Pmna-MnOCl2 monolayer is an intrinsic ferromagnetic semiconductor with an indirect band gap of 0.152 eV and a Curie temperature (TC) of 202 K, while the Pmmn-MnOCl2 monolayer is an intrinsic ferromagnetic Dirac semimetal with a high TC (910 K) and triaxial magnetic anisotropy. We also show that a Pmmn-MnOCl2 monolayer with a nontrivial band gap of 6.2 meV can achieve the quantum anomalous Hall effect (QAHE) with Chern number C = 1. Additionally, the existence of a gapless edge state can be flexibly regulated by choosing the terminal edges. Our studies reveal that the Pmmn-MnOCl2 monolayer can serve as a candidate material to achieve high-temperature QAHE. [ABSTRACT FROM AUTHOR]

0.5 at.% Cr:ZnGa2O4 precursor was synthesized by the co‐precipitation method with nitrates as raw materials, using ammonium carbonate as the precipitant. Low‐agglomerated Cr:ZnGa2O4 powders with an average particle size of 43 nm were obtained by calcining the precursor at 900℃ for 4 h. Using the powders as starting materials, 0.5 at.% Cr:ZnGa2O4 ceramics with an average grain size of about 515 nm were prepared by presintering at 1150℃ for 5 h in air and HIP post‐treatment at 1100℃ for 3 h under 200 MPa Ar. The in‐line transmittance of 0.5 at.% Cr:ZnGa2O4 ceramics with a thickness of 1.3 mm reaches 59.5% at the wavelength of 700 nm. The Cr:ZnGa2O4 ceramics can be effectively excited by visible light and produce persistent luminescence at 700 nm. For Cr:ZnGa2O4 transparent ceramics, the brightness of afterglow was larger than 0.32 mcd/m2 after 30 min, which is far superior to that of Cr:ZnGa2O4 persistent luminescence powders. [ABSTRACT FROM AUTHOR]

Transparent terbium aluminum garnet (TAG) ceramics were achieved by the vacuum sintering plus HIP post‐treating from the coprecipitated TAG nanoparticles. The influences of vacuum sintering temperature and sintering aid TEOS on the optical quality of the TAG ceramics were studied. The results show that with the increase of sintering temperature, the optical quality of TAG ceramics is improved gradually, and the in‐line transmittance of the TAG ceramics treated at 1720°C for 20 hours under vacuum and then HIP post‐treated at 1700°C for 3 hours under 200 MPa argon gas is 81.6% at 1064 nm. The sintering additive TEOS can improve the optical quality of TAG ceramics and inhibit the valence state change of Tb3+ ions to Tb4+ during the annealing process. The Verdet constant of the TAG ceramics at 632.8 nm is about −178 rad·T−1·m−1 at room temperature, which is 1.3 times that of the commercial TGG crystals (−134 rad·T−1·m−1). [ABSTRACT FROM AUTHOR]

Background: "Core microbes" play a key role in the development of caries and lead to microbial disorders. Our goal was to detect the core microbes associated with the microbiota imbalance in early childhood caries (ECC). Methods: Fifteen caries-free children and fifteen high-caries (DMFT ≥ 10) children aged 4–6 years old were recruited according to the diagnostic criteria of caries suggested by the WHO. The 16S rRNA genes from samples of plaque in saliva were amplified by PCR, and the PCR products were sequenced by the Illumina Miseq platform. The sequencing results were analyzed by professional software to determine the composition and structure of the saliva microorganisms. Results: There were statistically significant differences between the groups regarding the relative abundance of Streptococcus mutans (Wilcoxon rank-sum test, P < 0.05). No significant difference was found between the groups regarding other species or functional genes. Conclusion: S. mutans, together with other pathogens, may play a prominent role and act as "core microbes" in the occurrence and development of early childhood caries. [ABSTRACT FROM AUTHOR]

To investigate the microstructure of paleosol and its expansion characteristics, the paleosol of the Zaosheng #3 tunnel of the Yinxi high-speed railway was studied. Based on X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), nuclear magnetic resonance (NMR), and scanning electron microscopy techniques (SEM), the microstructure of the paleosol was analyzed in terms of the mineral composition, formation elements, pore structure, and particle morphology. Five groups of undisturbed and remolded soils with different moisture contents were tested for the unloaded expansion rate and loaded expansion rate. The results show that the mineral components of the paleosol are mainly quartz, potash feldspar, calcite, and hematite, with the highest-content-component quartz accounting for 45.4% of the total content; the clay mineral composition of the paleosol has the highest content of montmorillonite at 12.3%. The elemental composition of the paleosol is dominated by Al, Si, Ca, and Fe, which form expansive mineral components such as quartz and montmorillonite, creating inherent conditions for expansibility of the paleosol. The T2 distribution curves of the undisturbed and remolded paleosol are composed of three peaks. The pore distribution of paleosol mainly includes medium pores, followed by large pores, and the contents of small pores and superlarge pores are very small. In terms of particle contact, the undisturbed soil is mostly in the form of "surface-surface" and "surface-edge" contact, and the remolded soil is mainly in the form of "point-surface" and "point-point" contact. The unloaded expansion rate of remolded soil is approximately twice that of undisturbed soil. The rate of loaded expansion of both soils decreases with increasing moisture content. [ABSTRACT FROM AUTHOR]

With the increase in mining depth, the problem of the floor heave of a roadway is becoming increasingly prominent. Solving this problem for a deep high-stress roadway is the key to ensure safe supply and utilization of coal resources in China. This study investigates the floor heave of a horizontal transportation rock roadway at the depth of 960 m at the Xieyi Mine. A four-way loading simulation test frame similar to the Xieyi Mine was used to reproduce the high-stress environment of a deep roadway by loading different pressures on the roof, floor, and two sides of the roadway. The experimental results show that after the tunnel had been excavated, the surrounding rock failure could be divided into three stages: the initial deformation stage, fissure development stage, and mild deformation stage. The destruction time periods of these stages were 0–0.5 h, 0.5–2 h, and 2–6 h, and the destruction ranges were 0.4 m, 1 m, and 1.5 m, respectively. The amount of roof subsidence, the displacement of the two sides, and the floor heave influence each other, and the range of the bearing ring (5.6 m) of the floor is larger than that of the roof (3.4 m) after the surrounding rock has been damaged. The findings suggest that the floor should be supported first, before the two sides and the roof; then, the support of the key parts (roof and floor corners) should be strengthened. The roof, floor, and two sides are considered for controlling the deformation of the surrounding rock in a coupled trinity support mode. Because of the unfavorable conditions in the area, overexcavation backfill technology was used. The new support was successfully applied during the subsequent construction of the rock tunnel. Based on the long-term monitoring results of the surrounding rock deformation, the floor heave control yielded satisfactory results and maintained the long-term stability of the roadway. Therefore, this study can serve as a reference for preventing floor heave in similar high-stress roadways in the future. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a marine and estuarine bacterium that poses a major threat to human health worldwide. In this study, from 2017 to 2019, we evaluated 900 food samples collected from China in 2017, with the aim of determining the incidence and features of V. parahaemolyticus in ready-to-eat (RTE) foods, shrimp and fish in China. The contamination rates in these were 3.67, 19.33 and 10.67%, respectively, and the prevalence of V. parahaemolyticus was higher in summer than in winter. In addition, 101  V. parahaemolyticus strains were isolated. Our results suggested that most of the isolates were resistant to aminoglycosides based on the antimicrobial resistance patterns of these aquatic product isolates against 14 antimicrobial agents. Furthermore, most of the isolates were multidrug-resistant. Serotyping showed that the isolates of the O2 serotype comprised the maximum proportion. Enterobacterial repetitive intergenic consensus sequence (ERIC)-PCR results indicated that the isolates (n  = 101) could be classified into 12 clusters. There were 82 STs suggesting genetic variation and relatedness among these isolates. Our findings demonstrated the presence of V. parahaemolyticus in foods from Chinese retail markets and show that this methodology can be used for microbiological risk assessment in China. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a marine and estuarine bacterium that leads to damage of aquatic industry by foodborne outbreaks and possesses an enormous threat to food safety as well as human health worldwide. In the current study, we investigated 905 food samples (ready-to-eat foods, fish, and shrimp) from 15 provinces in China, and aimed to determine prevalence, biological characteristics and genetic diversity of presumptive V. parahaemolyticus isolates. Firstly, 14.17% of 240 fish samples, 15.34% of 365 shrimp samples and 3.67% of 300 RTE food samples were positive for potential V. parahaemolyticus. Secondly, 69 food samples (14.87%) collected in summer were positive for target isolates, while the rate of positive sample of 441 food samples in winter reached 7.26%. Thirdly, we purified 202 V. parahaemolyticus strains for further research. And antimicrobial susceptibility results of strains tested revealed that the highest resistance rate was observed for ampicillin (79.20%). At the same time, 148 (73.27%) of all isolates were classified and defined as multi-drug resistant foodborne bacteria. The results of PCR assay showed that the isolates being positive for the tdh , trh or both genes, were up to 9.90%, 19.80% or 3.96%. Besides, multiplex PCR test showed that the isolates carrying O2 serogroup were the most prevalent. Furthermore, sequence types (STs) of 108 isolates were obtained via multi-locus sequence typing. Not only 82 STs were detected, but also 41 of which were updated in the MLST database. Thus, our findings significantly demonstrated the high contamination rates of V. parahaemolyticus in fish and shrimp and it may possess potential threat for consumer health. We also provided up-to-date dissemination of antibiotic-resistant V. parahaemolyticus which is important to ensure the high efficacy in the treatment of human and aquatic products infections. Lastly, with the identification of 82 STs including 41 novel STs, this study significantly revealed the high genetic diversity among V. parahaemolyticus. All of our research improved our understanding on microbiological risk assessment in ready-to-eat foods, fish, and shrimp. [ABSTRACT FROM AUTHOR]

In this article, 5 at.% Yb:Lu2O3 transparent ceramics were fabricated by vacuum sintering combined with hot isostatic pressing (HIP) posttreatment using co‐precipitated nano‐powders. The influence of precipitant molar ratio, ammonium hydrogen carbonate, to metal ions (AHC/M3+, R value) on the properties of Yb:Lu2O3 precursors and calcined powders was investigated systematically. It was found that the powders with different R value calcined at 1100°C for 4 hours were pure cubic Lu2O3 but the morphologies of precursors and powders behaved differently. The opaque samples pre‐sintered at 1500°C for 2 hours grew into transparent ceramics after HIP posttreatment at 1750°C for 1 hour. The final ceramic with R = 4.8 showed the best optical quality with the in‐line transmittance of 79.7% at 1100 nm. The quasi‐CW laser operation was performed at 1034 nm and 1080 nm with a maximum output power up to 8.15 W as well as a corresponding slope efficiency of 58.4%. [ABSTRACT FROM AUTHOR]

Salmonella enterica is a common foodborne pathogen responsible for major global health problems such as paratyphoid fever and gastroenteritis. Here, we report the prevalence, antibiotic resistance phenotypes, serotypes, and molecular subtyping of Salmonella isolated from eggs in Guangdong, China. Out of 1,000 egg samples, 54 (5.40%) were positive. S. Enteritidis made up the largest proportion of samples with 11 serotypes. Antimicrobial susceptibility test indicated that most strains were resistant to β‐lactam, aminoglycoside, and tetracycline antibiotics (27.00%–40.00%). There were 37 STs based on MLST typing. MLST and ERIC‐PCR classified 54 isolates into three and five clusters, respectively, which revealed the genetic relatedness and diversity. In conclusion, frequent monitoring of eggs for Salmonella, antibiotic resistance profiles and genetic diversity is essential for improving food safety. [ABSTRACT FROM AUTHOR]

The 0.05 at.% Co:MgAl2O4 precursor was synthesized by the coprecipitation method from a mixed solution of magnesium, aluminum, and cobalt nitrates using ammonium carbonate as the precipitant. 0.05 at.% Co:MgAl2O4 transparent ceramics were successfully obtained via vacuum sintering and hot isostatic pressing (HIP) of 0.05 at.% Co:MgAl2O4 nanopowder calcined at 1100°C for 4 hours. The properties of powder and ceramics were comprehensively investigated. X‐ray diffraction (XRD) results showed that Co:MgAl2O4 nanopowder had a pure spinel phase. Also, the in‐line transmittances of the HIP posttreated Co:MgAl2O4 ceramics with the thickness of 1.2 mm were 82% at 400 nm and 84.7% at 900 nm. The average grain sizes of 0.05 at.% Co:MgAl2O4 ceramics before and after the HIP posttreatment were 11 and 28 μm, respectively. The calculated ground state absorption cross section of 0.05 at.% Co:MgAl2O4 ceramics was 2.9 × 10−19 cm2, indicating that this ceramics is a promising material applied as a saturable absorber for passive laser Q‐switches in the 1.3‐1.7 μm domain. [ABSTRACT FROM AUTHOR]

Using the tape casting method combined with vacuum sintering and hot isostatic pressing, high‐quality planar waveguide YAG/10 at.%Yb:YAG/YAG ceramics were successfully prepared. For the sample presintered at 1750°C for 30 hours and then HIPed at 1700°C for 3 hours in 200 MPa argon, the in‐line transmittance reached 82.5% at 400 nm and the average grain size was ~17.1 μm. The diffusion behaviors of Yb ions across the contact boundary between the cladding YAG layer and the core Yb:YAG layer were determined by Fick's second law. Then, a 1030 nm continuous‐wave (CW) Yb:YAG planar waveguide ceramic laser based on the structure of master oscillator power amplification (MOPA) was realized. After a single‐pass amplification, the maximum output of the ceramic slab (60 × 10 × 1 mm3) reached 1251 W and the corresponding optical‐to‐optical efficiency was 30.0%, which is the highest output power of a Yb:YAG planar waveguide ceramic laser to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a major foodborne pathogen associated with the consumption of aquatic products. The presence of this bacterium in ready-to-eat (RTE) foods has recently been reported. However, the genomic features and potential risks of V. parahaemolyticus isolated from RTE foods are poorly understood. To help understand the genome-wide characteristics of RTE food isolates, the complete genomes of 27 RTE food isolates were sequenced and compared to those of 20 clinical and 19 other environmental (e.g., water and aquatic product source) isolates using a comparative genomics approach. Analysis revealed that V. parahaemolyticus RTE food isolates had higher numbers of genes on average and possessed more accessory genes than isolates from other sources. Most RTE food isolates were positive for some known virulence-associated genes and pathogenicity islands (PAIs), and some of these isolates were genetically homologous to clinical isolates. Genome-wide association analysis revealed 79 accessory genes and 78 missense single-nucleotide polymorphisms that affected 11 protein-coding genes were significantly associated with RTE food sources. These genes were mostly involved in defense mechanisms and energy production and conversion according to functional annotation in the COG database. KEGG Pathway analysis showed that these genes mainly affected the biofilm formation of V. parahaemolyticus , and subsequent experiments confirmed that nearly all RTE food isolates possessed the ability to form biofilm. The biofilm formation can facilitate the persistence of V. parahaemolyticus in RTE foods, and the presence of virulence-associated genes poses a pathogenic potential to humans. Our findings highlight the potential risk of V. parahaemolyticus in Chinese RTE foods and illustrate the genomic basis for the persistence of these isolates. This study will aid in re-evaluating the food safety threats conferred by this bacterium. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a common foodborne pathogen found in seafood, and represents a major threat to human health worldwide. Low-temperature storage is an important seafood processing method, but is not sufficient to completely eliminate the bacteria and avoid foodborne illness. To determine the mechanisms behind such cold tolerance, RNA-seq and iTRAQ analyses were first performed to obtain the global transcriptomic and proteomic patterns of frozen squid and clinical V. parahaemolyticus isolates under cold conditions. The integrated analysis revealed the modulation of multiple pathways such as the co-occurrence of down-regulated pyruvate metabolism and up-regulated fatty acid biosynthesis, which likely contribute to V. parahaemolyticus cold tolerance. Furthermore, we found that increasing concentrations of pyruvate can reduce the fatty acid content to influence V. parahaemolyticus growth in cold conditions. Thus, regulation of pyruvate concentration may be an effective method to control this seafood-borne pathogen. [ABSTRACT FROM AUTHOR]

Ho:Lu3Al5O12(Lu AG) transparent ceramics are potential 2 μm eye-safe laser materials. Polycrystalline 0.8 at.% Ho:Lu AG ceramics with high optical quality were successfully fabricated by solid-state reactive sintering of high-purity oxide powders. The microstructure, the optical transmission, the spectrum characteristic, and the laser performance were investigated in this paper. The average grain size of Ho:Lu AG ceramics vacuum sintered at 1830°C for 30 hour is about 14 μm. The in-line transmittance of the sample is measured to be 81.7% and 82.0% at 1000 and 2250 nm, respectively. The absorption and the emission cross sections are calculated to be 0.88 × 10−20 cm2 at 1906 nm and 1.26 × 10−20 cm2 at 2094 nm. Using a thulium-doped yttrium-lithium-fluoride (Tm: YLF) laser with the central wavelength of 1907.5 nm as the pump source, 2.67 W continuous wave ( CW) laser operation at 2100.74 nm was obtained with a slope efficiency of 26.5%. The beam quality factor M2 was calculated to be 1.1, which indicated nearly diffraction-limited beam propagation and the laser was the fundamental TEM00 Gaussian mode. [ABSTRACT FROM AUTHOR]

In this study, transparent ZnS ceramics were hot pressed from precipitated wurtzite nanopowders. Influences of sintering temperature on wurtzite-to-sphalerite phase transition and densification behavior have been investigated. Maximum sphalerite phase content and highest densification were simultaneously obtained in the sample hot pressed at 900°C with uniaxial pressure of 250 MPa for 2 h, which accounts for the highest transmittance above 55% and 70% in the range 2-5 μm and 5-13 μm, respectively. Preferred orientation of wurtzite grains in [002] direction paralleled to the press direction was also observed, which is supposed to be benefit to transmittance by reducing birefraction and second-phase scattering. Furthermore, second-phase scattering caused by wurtzite grains has been investigated. It is found that fine grains are conducive to hot-pressed ZnS ceramics with high transmittance, especially in the short-wavelength range. [ABSTRACT FROM AUTHOR]

Spring water is an important direct drinking water resource. Enterococcus faecalis is a significant opportunistic pathogen from environment that causes human neonatal sepsis and urinary tract infections. Our study investigated the prevalence, virulence genes, antimicrobial resistance, and molecular characterization of E. faecalis from spring water in Guangdong, China. A total of 285 spring water samples were collected from January 2017 to January 2018, in which 47 (16.49%) samples were contaminated by E. faecalis. Antimicrobial susceptibility result showed that many isolates were resistant to tetracycline (93.6%), gentamicin (29.8%), and ciprofloxacin (25.5%). The virulence gene test revealed the positive rate of gelE, asa1, ace, and cylA were 100, 82.3, 76.6, and 70.2%, respectively. Enterobacterial repetitive intergenic consensus‐polymerase chain reaction and multilocus sequence typing classified 47 isolates into 12 and 5 clusters, respectively, which revealed the genetic relatedness and diversity. This finding illustrated the presence of virulence genes and provided understanding on the spread of antibiotic‐resistant and genetic diversity isolates. It can help us gradually increase our knowledge of microbiological risk management in E. faecalis from spring water. Practical applications: Investigating the prevalence of Enterococcus faecalis isolates from spring water could increase this microbial safety ondrinking water. In our research, antibiotic susceptibility, virulence genes, serotypingand molecular characteristic were selected to thorough comparison among Enterococcus faecalis isolates. Spring water is common in China as drinking water, then understanding the dissemination and monitoring the prevalence of this microorganism is necessary to improve the drinking water safety. [ABSTRACT FROM AUTHOR]

We report a comprehensive characterization of a 10 at.% Yb3+-doped YSAG (Yb:Y3ScxAl(5−x)O12, x = 1.5) ceramic, including microstructural, spectroscopic and laser properties. Moreover, we illustrate and discuss the fabrication technique. Yb3+ in YSAG features a broader absorption and emission band than in traditional YAG, which is advantageous for laser applications (i.e., tunable laser sources, ultrafast pulse generation). Pumping in a quasi continuous wave regime at 936 nm, the ceramic has shown good laser performance as the maximum output power was 6.3 W with a corresponding slope efficiency (ηs) of 67.8%. In continuous wave regime instead, the maximum output power was 5 W with ηs = 52.7%. The laser emission wavelengths in free running were λL = 1051 nm and λL = 1031 nm, depending on the output coupler transmission. Finally, by a tunable cavity we obtained laser emission spanning from 991.5 to 1073 nm, i.e., 81.5 nm, which is the broadest tuning range ever reported for this material, to the best of our knowledge. [ABSTRACT FROM AUTHOR]

Cronobacter sakazakii is an important foodborne pathogens causing rare but life-threatening diseases in neonates and infants. CRISPR-Cas system is a new prokaryotic defense system that provides adaptive immunity against phages, latter play an vital role on the evolution and pathogenicity of host bacteria. In this study, we found that genome sizes of C. sakazakii strains had a significant positive correlation with total genome sizes of prophages. Prophages contributed to 16.57% of the genetic diversity (pan genome) of C. sakazakii, some of which maybe the potential virulence factors. Subtype I-E CRISPR-Cas system and five types of CRISPR arrays were found in the conserved site of C. sakazakii strains. CRISPR1 and CRISPR2 loci with high variable spacers were active and showed potential protection against phage attacks. The number of spacers from two active CRISPR loci in clinical strains was significant less than that of foodborne strains, it maybe a reason why clinical strains were found to have more prophages than foodborne strains. The frequently gain/loss of prophages and spacers in CRISPR loci is likely to drive the quick evolution of C. sakazakii. Our study provides a new insight into the co-evolution of phages and C. sakazakii. [ABSTRACT FROM AUTHOR]