[Incidence of late-onset sepsis in very low birth weight and extremely low birth weight infants and risk factors for late-onset sepsis].

OBJECTIVE: To investigate the incidence of late-onset sepsis (LOS) in very low birth weight (VLBW) and extremely low birth weight (ELBW) infants in the neonatal intensive care unit (NICU) and the risk factors for LOS. METHODS: A retrospective analysis was performed for the clinical data of all VLBW and ELBW infants who were hospitalized in the NICU between January 2011 and December 2013. According to the presence or absence of LOS, these infants were divided into LOS group and non-LOS group. The incidence and mortality rates of LOS, common pathogenic bacteria, and risk factors for LOS were analyzed. RESULTS: Of the 226 VLBW and ELBW infants, 117 (51.8%) developed LOS, among whom 45 had a confirmed diagnosis of LOS and 72 had a clinical diagnosis of LOS. The LOS group had a significantly higher mortality rate than the non-LOS group [13.7% (16/117) vs 4.6% (5/109); P<0.05]. Bacterial culture found 51 strains of pathogenic bacteria, among which 32 (63%) were Gram-negative bacteria, 16 (31%) were Gram-positive bacteria, and 3 (6%) were fungi. The multivariate logistic regression analysis showed that gestational age, small for gestational age (SGA), duration of parenteral nutrition, peripherally inserted central catheter (PICC) placement, and mechanical ventilation were independent risk factors for LOS in VLBW and ELBW infants (OR=0.84, 1.59, 1.34, 3.11, and 4.55 respectively; P<0.05). CONCLUSIONS: LOS has high incidence and mortality rates in VLBW and ELBW infants. Common pathogenic bacteria of LOS are Gram-negative bacteria. Low gestational age, long duration of parenteral nutrition, SGA, PICC placement, and mechanical ventilation may increase the risk of LOS in VLBW and ELBW infants.

Recent advancements in the discovery of small-molecule non-nucleoside inhibitors targeting SARS-CoV-2 RdRp.

The RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2 plays a pivotal role in the life cycle of the novel coronavirus and stands as a significant and promising target for anti-SARS-CoV-2 drugs. Non-nucleoside inhibitors (NNIs), as a category of compounds directed against SARS-CoV-2 RdRp, exhibit a unique and highly effective mechanism, effectively overcoming various factors contributing to drug resistance against nucleoside inhibitors (NIs). This review investigates various NNIs, including both natural and synthetic inhibitors, that closely interacting with the SARS-CoV-2 RdRp with valid evidences from in vitro and in silico studies.

Genome-wide analysis of the cyclin gene family in tomato.

Cyclins play important roles in cell division and cell expansion. They also interact with cyclin-dependent kinases to control cell cycle progression in plants. Our genome-wide analysis identified 52 expressed cyclin genes in tomato. Phylogenetic analysis of the deduced amino sequences of tomato and Arabidopsis cyclin genes divided them into 10 types, A-, B-, C-, D-, H-, L-, T-, U-, SDS- and J18. Pfam analysis indicated that most tomato cyclins contain a cyclin-N domain. C-, H- and J18 types only contain a cyclin-C domain, and U-type cyclins contain another potential cyclin domain. All of the cyclin genes are distributed throughout the tomato genome except for chromosome 8, and 30 of them were found to be segmentally duplicated; they are found on the duplicate segments of chromosome 1, 2, 3, 4, 5, 6, 10, 11 and 12, suggesting that tomato cyclin genes experienced a mass of segmental duplication. Quantitative real-time polymerase chain reaction analysis indicates that the expression patterns of tomato cyclin genes were significantly different in vegetative and reproductive stages. Transcription of most cyclin genes can be enhanced or repressed by exogenous application of gibberellin, which implies that gibberellin maybe a direct regulator of cyclin genes. The study presented here may be useful as a guide for further functional research on tomato cyclins.

Genome-wide analysis of plant-specific Dof transcription factor family in tomato.

The Dof (DNA binding with One Finger) family encoding single zinc finger proteins has been known as a family of plant-specific transcription factors. These transcription factors are involved in a variety of functions of importance for different biological processes in plants. In the current study, we identified 34 Dof family genes in tomato, distributed on 11 chromosomes. A complete overview of SlDof genes in tomato is presented, including the gene structures, chromosome locations, phylogeny, protein motifs and evolution pattern. Phylogenetic analysis of 34 SlDof proteins resulted in four classes constituting six clusters. In addition, a comparative analysis between these genes in tomato, Arabidopsis and rice was also performed. The tomato Dof family expansion has been dated to recent duplication events, and segmental duplication is predominant for the SlDof genes. Furthermore, the SlDof genes displayed differential expression either in their transcript abundance or in their expression patterns under normal growth conditions. This is the first step towards genome-wide analyses of the Dof genes in tomato. Our study provides a very useful reference for cloning and functional analysis of the members of this gene family in tomato and other species.

Microstructure Evolution of 7075 Aluminum Alloy by Rotary.

This study proposed a rotary back extrusion (RBE) process for an open punch, which is used to produce high-performance 7075 aluminum alloy cup-shaped piece. The RBE experiment was carried out on the Gleeble-3500 testing machine at 400 °C and compared with the conventional back extrusion (CBE). The microstructure was analyzed by optical microscope, scanning electron microscope and DEFORM-3D simulation software. The results shown that compared with CBE, RBE can significantly increase the equivalent strain value and deformation uniformity of 7075 aluminum alloy cup-shape pieces. RBE deformation increases the accumulated strain of the piece, and the rotation of the die causes the piece to produce shear strain, which increases the overall strain of the cup-shape piece. The proportion of dynamic recrystallization increases, and the grain refinement was obvious. The micro-hardness value of the RBE sample is higher than that of the CBE sample, which could be the result of grain refinement strengthening. What is more, RBE and CBE have different metal flow laws.

Anisotropic Low Cycle Behavior of the Extruded 7075 Al Alloy.

The quasi-static and low cycle fatigue tests of extruded 7075 Al alloy (Φ200 mm) were investigated in three directions: the extrusion direction (ED), the radial direction (RD), and 45° with ED (45°). Grain morphology analysis, texture measurement, and fatigue fracture characterization were conducted to discuss the relationship between microstructure and mechanical properties. The experimental results showed that the ED specimen had higher ultimate tensile strength (UTS) and low cycle fatigue (LCF) properties, which were mainly attributed to the following three causes. First, the grain boundaries (GBs) had an obvious effect on the crack growth. The number of GBs in the three directions was different due to the shape of the grains elongated along the ED. Second, the sharp <111> texture and the small Schmidt factor along the ED explained the higher ultimate tensile strength (UTS) of the ED specimens. Third, fatigue fracture observation showed that the ED specimen had a narrow fatigue striation spacing, which indicated that the plastic deformation of the ED specimen was the smallest in each cycle. In addition, two fatigue prediction models were established to predict the LCF life of extruded 7075 Al alloy, based on the life response behavior of the three directions under different strains.

Characterization of Plasmid Co-Harboring NDM-1 and SHV-12 from a Multidrug-Resistant Citrobacter freundii Strain ZT01-0079 in China.

BACKGROUND: The emergence of multidrug-resistant Citrobacter freundii poses daunting challenges to the treatment of clinical infections. The purpose of this study was to characterize the genome of a C. freundii strain with an IncX3 plasmid encoding both the bla NDM-1 and bla SHV-12 genes. METHODS: Strain ZT01-0079 was isolated from a clinical urine sample. The Vitek2 system was used for identification and antimicrobial susceptibility testing. The presence of bla NDM-1 was detected by PCR and sequencing. Conjugation experiments and Southern blotting were performed to determine the transferability of the bla NDM-1- carrying plasmid. Nanopore and Illumina sequencing were performed to better understand the genomic characteristics of the strain. RESULTS: Strain ZT01-0079 was identified as C. freundii, and the coexistence of bla NDM-1 and multiple drug resistance genes was confirmed. Electrophoresis and Southern blotting showed that bla NDM-1 was located on a ~53kb IncX3 plasmid. The NDM-1-encoding plasmid was successfully transferred at a frequency of 1.68×10-3. Both the bla NDM-1 and bla SHV-12 genes were located on the self-transferable IncX3 plasmid. CONCLUSION: The rapid spread of the IncX3 plasmid highlights the importance of continuous monitoring of the prevalence of NDM-1-encoding Enterobacteriaceae. Mutations of existing carbapenem resistance genes will bring formidable challenges to clinical treatment.

Gender differences in the development of semantic and spatial processing of numbers.

This study recruited kindergarteners and first graders to investigate gender and grade differences in semantic and spatial processing of number magnitude. Results based on the Bayesian statistics showed that (1) there was extreme evidence in favour of grade differences in both semantic processing and spatial processing; (2) there were no gender differences in semantic processing; and (3) boys developed earlier than girls in spatial processing of numbers, especially for the more difficult task. These results are discussed in terms of gender differences in cognitive mechanisms underlying semantic and spatial processing of number magnitude.

Metagenomic Diagnosis for a Culture-Negative Sample From a Patient With Severe Pneumonia by Nanopore and Next-Generation Sequencing.

Rapid and accurate etiologic diagnosis accelerates targeted antimicrobial therapy. Metagenomic analysis has played a critical role in pathogen identification. In this study, we leveraged the advantages of both the MinION and BGISEQ-500 platforms to make a bacteriologic diagnosis from a culture-negative lung tissue sample from an immunocompromised patient with severe pneumonia. Real-time nanopore sequencing rapidly identified Klebsiella pneumoniae by an 823 bp specific sequence within 1 min. Genomic analysis further identified blaSHV-12, blaKPC-2, blaTEM-1, blaCTX-M-65, and other resistance genes. The same sample was further sequenced on the BGISEQ-500 platform, which presented consistent results regarding the most top dominant pathogens and provided additional information of resistance genes. Revised antibiotic treatment was followed by the patient's clinical recovery. Though sample preparation and the interpretation of final results still need to be improved further, metagenomic sequencing contributes to the accurate diagnosis of culture-negative infections and facilitates the rational antibiotic therapy.

Fatty acid composition of diet, cord blood and breast milk in Chinese mothers with different dietary habits.

The influence of two different dietary patterns on maternal fatty acid (FA) intake on the composition of umbilical cord blood plasma phospholipids and transitional breast milk was investigated. A 7-day dietary record was completed in the last trimester of pregnancy by women living in an inland and a coastal area of south-eastern China. The FA composition in maternal diet was calculated using the 2002 Chinese food composition database. Cord blood and transitional breast milk samples were collected and their FA composition was analyzed by capillary gas-liquid chromatography. Mothers in the coastal area showed higher intake of long-chain polyunsaturated FA (LCPUFA) including docosahexaenoic acid (DHA, 22:6omega) and eicosapentaenoic acid (EPA,20:5omega3) but lower linoleic acid (LA, 18:2omega6) and alpha-linolenic acid (ALA, 18:3omega3) than the mothers in the inland area. The intake of arachidonic acid (AA, 20:4omega6) did not differ between the two areas. LA, ALA, AA and DHA in breast milk of day 5 reflected the maternal diet except that the EPA content in breast milk at day 5 was similar for the areas. LA, ALA and AA were lower and EPA higher in umbilical cord plasma phospholipids in infants from the costal compared to the inland area. There were significant differences in maternal intakes of FA confirming different dietary habits, which influenced the FA composition of cord plasma phospholipids and transitional breast milk. Since FA influence gene expression the found variation implies that the long-term follow-up of this cohort will be interesting.