Mutations in porin LamB contribute to ceftazidime-avibactam resistance in KPC-producing Klebsiella pneumoniae.

Ceftazidime-avibactam (CAZ-AVI) shows promising activity against carbapenem-resistant Klebsiella pneumoniae (CRKP), however, CAZ-AVI resistance have emerged recently. Mutations in KPCs, porins OmpK35 and/or OmpK36, and PBPs are known to contribute to the resistance to CAZ-AVI in CRKP. To identify novel CAZ-AVI resistance mechanism, we generated 10 CAZ-AVI-resistant strains from 14 CAZ-AVI susceptible KPC-producing K. pneumoniae (KPC-Kp) strains through in vitro multipassage resistance selection using low concentrations of CAZ-AVI. Comparative genomic analysis for the original and derived mutants identified CAZ-AVI resistance-associated mutations in KPCs, PBP3 (encoded by ftsI), and LamB, an outer membrane maltoporin. CAZ-AVI susceptible KPC-Kp strains became resistant when complemented with mutated blaKPC genes. Complementation experiments also showed that a plasmid borne copy of wild-type lamB or ftsI gene reduced the MIC value of CAZ-AVI in the induced resistant strains. In addition, blaKPC expression level increased in four of the six CAZ-AVI-resistant strains without KPC mutations, indicating a probable association between increased blaKPC expression and increased resistance in these strains. In conclusion, we here identified a novel mechanism of CAZ-AVI resistance associated with mutations in porin LamB in KPC-Kp

Global emergence of a hypervirulent carbapenem-resistant <i>Escherichia coli </i>ST410 clone

Carbapenem-resistant Escherichia coli (CREC) ST410 has recently emerged as a major global health problem. Here, we report a shift in CREC prevalence in Chinese hospitals between 2017 and 2021 with ST410 becoming the most commonly isolated sequence type. Genomic analysis identifies a hypervirulent CREC ST410 clone, B5/H24RxC, which caused two separate outbreaks in a children's hospital. It may have emerged from the previously characterised B4/H24RxC in 2006 and has been isolated in ten other countries from 2015 to 2021. Compared with B4/H24RxC, B5/H24RxC lacks the blaOXA-181-bearing X3 plasmid, but carries a F-type plasmid containing blaNDM-5. Most of B5/H24RxC also carry a high pathogenicity island and a novel O-antigen gene cluster. We find that B5/H24RxC grew faster in vitro and is more virulent in vivo. The identification of this newly emerged but already globally disseminated hypervirulent CREC clone, highlights the ongoing evolution of ST410 towards increased resistance and virulence. </p

A GPRS Based Monitoring and Management System for Classification Results of Image by CCD Camera

Data acquisition plays an important role in the field of modern industry. In many cases, remote data should be transferred to monitor center which is far away from the manufacturing field. This paper presents a remote transmission system for the classification results of images which are got by a CCD sensor. The utilization of web application framework gives this system the advantage of minimum research work on the monitor center. A GPRS DTU treated as an information transmitting terminal was used to transmit a custom format of the classified images. In the system, The Users can use the browser anywhere to log on the website of the system so as to view and manage the experimental stations, sensors and users’ information of the system. The results shows that the system can transmit and management the figures classified by Support Vector Machines (SVM). The figures those use other classified method will be tested in the future

A new deep-sea species of Elliptiolucina Cosel &amp;amp; Bouchet, 2008 (Bivalvia, Lucinida, Lucinidae) from cold seep of the South China Sea

The increasing discoveries of new species of the family Lucinidae in the last two decades indicated a surprising diversity of chemosynthetic lucinids in the deep sea, especially in the Indo-West Pacific. However, only a few records have been reported from the South China Sea. A new lucinid species Elliptiolucina subovalis sp. nov. is here reported from a deep-sea cold seep site of the South China Sea. The new species is distinct from its congeners by possessing a strong anterior lateral tooth on the right valve and anterior tapering, subrectangular-oval shells. Sequences of three genes (18S rRNA, 28S rRNA, and CytB) were used to analyze its relationships with other species in the subfamily Myrteinae and confirm its taxonomic placement. The result supports the monophyly of Myrteinae but also demonstrates the polyphyly of Elliptiolucina. The new species has a close relationship with E. williamsae and Rostrilucina garuda, but is not closely related to congener E. ingens. By comparing morphological characters, we suggest that E. ingens should not belong to the genus Elliptiolucina. The basal two of three deep-sea clades recognized in Myrteinae may indicate the deep-sea origin of this subfamily. Our results add to the known diversity of deep-sea lucinids and molecular information for poorly studied Myrteinae and highlight the necessity of further investigation on deep-sea lucinids of the South China Sea

NIR Hyperspectral Imaging Technology Combined with Multivariate Methods to Identify Shrimp Freshness

In this study, a hyperspectral imaging system of 866.4&ndash;1701.0 nm, combined with a variety of spectral processing methods were adopted to identify shrimp freshness. To gain the optimal model combination, three preprocessing methods (Savitzky-Golay first derivative (SG1), multivariate scatter correction (MSC), and standard normal variate (SNV)), three characteristic wavelength extraction algorithms (random frog algorithm (RFA), uninformative variables elimination (UVE), and competitive adaptive reweighted sampling (CARS)), and four discriminant models (partial least squares discrimination analysis (PLS-DA), least squares support vector machine (LSSVM), random forest (RF), and extreme learning machine (ELM)) were employed for experimental study. First of all, due to the full wavelength modeling analysis, three preprocessing methods were utilized to preprocess the original spectral data. The analysis showed that the spectral data processed by the SNV method had the best performance among the four discriminant models. Secondly, due to the characteristic wavelength modeling analysis, three characteristic wavelength extraction algorithms were utilized to extract the characteristic wavelength of the SNV-processed spectral data. It was found that the CARS algorithm achieved the best performance among the three characteristic wavelength extraction algorithms, and the combining adoption of the ELM model and different characteristic wavelength extraction algorithms obtained the best results. Therefore, the model based on SNV-CARS-ELM obtained the best performance and was elected as the optimal model. Lastly, for accurately and explicitly displaying the refrigeration days of shrimps, the original hyperspectral images of shrimps were substituted into the SNV-CARS-ELM model, thus obtaining the general classification accuracy of 97.92%, and the object-wise method was used to visualize the classification results. As a result, the method proposed in this study can effectively detect the freshness of shrimps

Micromorphology and Mechanical and Dielectric Properties of Bismaleimide Composite Modified by Multiwalled Carbon Nanotubes and Polyethersulfone

Multiwalled carbon nanotubes (MWCNTs) were modified by oxidizing agent to obtain O-MWCNTs, and the surface of it was coated with active group. 4,4′-Diaminodiphenylmethane bismaleimide (MBMI) was used as matrix, 3,3′-diallyl bisphenol A (BBA) and bisphenol-A diallyl ether (BBE) were used as reactive diluent, polyethersulfone (PES) as toughening agent, and O-MWCNTs as modifier; OMWCNT/PES-MBAE composite was prepared through in situ sol-gel method. The effect of PES and OMWCNTs on the mechanical and dielectric properties of composite was analyzed, and the microstructure was examined by transmission electron microscope (TEM) and scanning electron microscope (SEM). The mechanism of composite toughened by PES and OMWCNTs was observed and analyzed. The results showed that Diels-Alder reaction between MBMI and allyl compounds occurred completely and unsaturated double bond disappeared. O-MWCNTs and PES resin dispersed smoothly in polymer matrix and were used as reinforcement, and PES resin and O-MWCNTs could synergistically improve the properties of the composite and exhibited a typical ductile fracture. The impact and bending strengths were 16.09 kJ/m2 and 153.57 MPa, which were 74.32% and 53.08% higher than those of the MBAE matrix, respectively, and the dielectric constant and the dielectric loss were 3.76 (100 Hz) and 2.79 × 10−3 (100 Hz), when the content of PES was 2 wt% and O-MWCNTs was 0.02 wt%. The outstanding properties of the material made it play an important role in high-performance insulating material applications

Optimal Decomposition for the Monthly Contracted Electricity of Cascade Hydropower Plants Considering the Bidding Space in the Day-Ahead Spot Market

With the gradual opening of China’s electricity market, it is effective for cascade hydropower plants to simultaneously participate in both the monthly contract market and the day-ahead spot market to obtain higher power generation benefits. Hence, this paper studies the optimal decomposition model for the monthly contracted electricity of cascade hydropower plants considering the bidding space in the day-ahead spot market. The close hydraulic and electric connection between cascade hydropower plants, the implementation requirements of contracted electricity, and the uncertainty of the day-ahead market clearing price are all well considered. Several linearization techniques are proposed to address the nonlinear factors, including the objective function and the power generation function. A successive approximation (SA) approach, along with a mixed-integer linear programming (MILP) approach, is then developed to solve the proposed model. The presented model is verified by taking the decomposition of the monthly contracted electricity of cascade hydropower plants in China as an example. The results indicate that the developed model has high computational efficiency and can increase the power generation benefits compared with the conventional deterministic model. The effect of the penalty coefficient for imbalanced monthly contracted electricity is also evaluated, which provides a practical reference for market managers