No abstract

Double-network (DN) hydrogels with high strength and toughness have been developed as promising materials. Herein, we explored a dual physically cross-linked polyacrylamide/xanthan gum (PAM/XG) DN hydrogel. The nonchemically cross-linked PAM/XG DN hydrogels exhibited fracture stresses as high as 3.64 MPa (13 times higher than the pure PAM single network hydrogel) and compressive stresses at 99% strain of more than 50 MPa. The hydrogels could restore their original shapes after continuously loading-unloading tensile and compressive cyclic tests. In addition, the PAM/XG DN hydrogels demonstrated excellent fatigue resistance, notch-insensitivity, high stability in different harsh environments, and remarkable self-healing properties, which might result from their distinctive physical-cross-linking structures. The attenuated total reflectance infrared spectroscopy (ATR-IR) and dynamic thermogravimetric analysis (TGA) results indicated that there were no chemical bonds (only hydrogen bonds) between the XG and PAM networks. The PAM/XG DN hydrogel synthesis offers a new avenue for the design and construction of DN systems, broadening current research and applications of hydrogels with excellent mechanical properties.

Matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) has revolutionized the microbial identification, especially in the clinical microbiology laboratories. However, although numerous studies on the identification of microorganisms by MALDI‐TOF MS have been reported previously, few studies focused on the effect of pretreatment on identification. Due to the sensitivity of MALDI‐TOF MS, different preparation methods will lead to changes in microbial protein fingerprints. In this study, for evaluating a more appropriate preparation method for the clinical microbiology identification, we analyzed the performance of three sample preparation methods on two different MALDI‐TOF MS systems. A total of 321 clinical isolates, 127 species, were employed in the comparative study of three different sample preparation methods including the direct colony transfer method (DCTM), the on‐target extraction method (OTEM), and the in‐tube extraction method (ITEM) compatible with MALDI‐TOF MS. All isolates were tested on the Microflex LT and Autof ms1000 devices. The spectra were analyzed using the Bruker biotyper and the Autof ms1000 systems. The results were confirmed by 16/18S rRNA sequencing. Results reveal that the accuracies of isolates identification by Bruker biotyper successfully identified 83.8%, 96.0%, and 95.3% after performing the DCTM, OTEM, and ITEM, respectively, while the Autof ms1000 identified 97.5%, 100%, and 99.7%. These data suggested that the identification rates are comparable among the three preparation methods using the Autof ms1000 and Bruker microflex LT systems but the OTEM is more suitable and necessary for clinical application, owing to its key advantages of simplicity and accuracy.

This study aimed to investigate antibiotic resistance genes in the multidrug-resistant (MDR) Acinetobacter baumannii (A. baumanii) strain, MDR-SHH02, using whole-genome sequencing (WGS). The antibiotic resistance of MDR-SHH02 isolated from a patient with breast cancer to 19 types of antibiotics was determined using the Kirby-Bauer method. WGS of MDR-SHH02 was then performed. Following quality control and transcriptome assembly, functional annotation of genes was conducted, and the phylogenetic tree of MDR-SHH02, along with another 5 A. baumanii species and 2 Acinetobacter species, was constructed using PHYLIP 3.695 and FigTree v1.4.2. Furthermore, pathogenicity islands (PAIs) were predicted by the pathogenicity island database. Potential antibiotic resistance genes in MDR-SHH02 were predicted based on the information in the Antibiotic Resistance Genes Database (ARDB). MDR-SHH02 was found to be resistant to all of the tested antibiotics. The total draft genome length of MDR-SHH02 was 4,003,808 bp. There were 74.25% of coding sequences to be annotated into 21 of the Clusters of Orthologous Groups (COGs) of protein terms, such as 'transcription' and 'amino acid transport and metabolism'. Furthermore, there were 45 PAIs homologous to the sequence MDRSHH02000806. Additionally, a total of 12 gene sequences in MDR-SHH02 were highly similar to the sequences of antibiotic resistance genes in ARDB, including genes encoding aminoglycoside-modifying enzymes [e.g., aac(3)-Ia, ant(2″)-Ia, aph33ib and aph(3′)-Ia], β-lactamase genes (bl2b_tem and bl2b_tem1), sulfonamide-resistant dihydropteroate synthase genes (sul1 and sul2), catb3 and tetb. These results suggest that numerous genes mediate resistance to various antibiotics in MDR-SHH02, and provide a clinical guidance for the personalized therapy of A. baumannii-infected patients.

Before the coronavirus disease 2019 (COVID-19) pandemic, laboratory medicine management activities mainly remain inside of the laboratory, including reagent and instrument maintenance, daily quality assessment, errors elimination, turnaround time reduction, etc. The development process is briefly divided into several distinct phases, including standardization of biological reference material, 1,2 introduction of quality control, 3,4 establishment of standard operating procedures, 5,6 laboratory automation, and laboratory management