A color extraction algorithm by segmentation.

The segmentation and extraction on color features can provide useful information for many different application domains. However, most of the existing image processing algorithms on feature extraction are gray image-based and consider only one-dimensional parameters. In order to carry out a fast and accurate color feature extraction, this paper proposes a color extraction algorithm by segmentation that is called a color extraction algorithm This algorithm is compared under different color distribution situations, and the extraction effect on color is also shown by the combination of the segmentation and feature extraction algorithms. Experimental results show that such segmentation algorithm has some advantages for color segmentation. In the fuzzy color image preprocessing, this paper gives the location method of region of interest. Moreover, compared with other existing extraction algorithms, the presented segmentation extraction algorithm in this paper not only has higher accuracy, shorter extraction time and stronger anti-interference ability, but also has better effect on more divergent color edge. Experimental evaluation of the proposed color extraction algorithm demonstrates dominance over existing algorithms for feature extraction. These researches in this paper provide a new way of thinking for color feature extraction by segmentation, which has an important theoretical references and practical significance.

Design, optimization and application of reformer in a marine natural gas engine: A numerical and experimental study.

In the present study, the models of flow, heat transfer and reforming of 2-D single reforming tube and 3-D reformer core inside the reformer were implemented by CFD. The models were evaluated by comparison of simulations with data derived from a catalytic packed-bed reactor. In addition, a NG engine-reformer experimental system was established. Thereby, the experimental studies on performance of the reformer and engine under different excess air coefficient (λ), exhaust gas recirculation rate (XEGR) and reformed NG supply (CH4/O2, M/O value) were conducted based on IMO Tier III and China II emission standards. The results showed that oxidation and steam reforming reactions of methane were dominant in the process of exhaust gas-methane reforming and had obvious reaction sequence. For the reformer optimization, the design parameters were determined: GHSV = 16,000 h-1 and L/D = 7 for single reforming tube; diffuse angle of 30° and one deflector for reformer core. Besides, for experiments of REGR system, the reformer should operate under the condition of near M/O = 2-2.5 and XEGR = 7.3 % with high λ to achieve an optimal H2 yield and efficient H2 production. Compared with original engine under 50 % load and XEGR = 10.4 %, the brake thermal efficiency of the engine with REGR was increased by the maximum of 0.7 % (λ = 1.31). Noted that the maximum 85.5 % reduction of HC + NOx and the minimum 64.1 % treatment rate of CH4 could be obtained for meeting China II at λ = 1.25. Under different propeller loads, HC + NOx and CO emissions could both satisfy IMO Tier III and China II standards via adjusting the matched strategy of λ and XEGR. To meet fully China II standard, the minimum treatment rate of CH4 by the post-treatment unit needed to reach 79 %, 64 % and 64 % at 25 %, 50 % and 75 % load, respectively.

Comparison of the Distribution and Changes in the Antibiotic Resistance of Clinical Bacterial Isolates from the Lower Respiratory Tract of Children in Shenzhen Before the Epidemic, During the Epidemic, and During the Period of Normalized Prevention and Control of COVID-19.

INTRODUCTION: This study aimed to understand the impact of the coronavirus disease 2019 (COVID-19) epidemic on the distribution and antibiotic resistance of pathogenic bacteria isolated from the lower respiratory tract of children in our hospital. METHODS: Antimicrobial susceptibility tests were performed on bacteria isolated clinically from the lower respiratory tracts of children in our hospital from 2018 to 2021 by the Kirby-Bauer method and automated systems. RESULTS: From 2018 to 2021, the top three lower respiratory tract clinical isolates in our hospital were Streptococcus pneumoniae, Moraxella catarrhalis, and Haemophilus influenzae. These three species showed obvious seasonal epidemic patterns, and their numbers decreased significantly during the COVID-19 epidemic, from 4559 in 2019 to 1938 in 2020. Bacterial resistance to antibiotics also changed before and after the COVID-19 epidemic. The annual proportions of methicillin-resistant S. aureus (MRSA) were 41%, 37.4%, 26.2%, and 29.8%. The resistance rates of Klebsiella pneumoniae to ceftriaxone were 40.5%, 51.9%, 35.3%, and 53.3%, and the detection rates of carbapenem-resistant K. pneumoniae (CRKP) were 2.7%, 11.1%, 5.9%, and 4.4%. The detection rates of ß-lactamase-producing H. influenzae were 51.9%, 59.2%, 48.9%, and 55.3%. The rate of MRSA, ceftriaxone-resistant K. pneumoniae, CRKP, and ß-lactamase-producing H. influenzae decreased significantly in 2020 compared with 2019, whereas that of carbapenem-resistant P. aeruginosa and carbapenem-resistant A. baumannii increased. The detection rates of ß-lactamase-negative ampicillin-resistant H. influenzae (BLNAR) gradually increased over the 4 years. CONCLUSIONS: Protective measures against COVID-19, including reduced movement of people, hand hygiene, and surgical masks, may block the transmission of S. pneumoniae, H. influenzae, and M. catarrhalis and reduce the detection rate of MRSA, ceftriaxone-resistant K. pneumoniae, CRKP, and ß-lactamase-producing H. influenzae.

Case report: Hemophagocytic lymphohistiocytosis in a child with primary immunodeficiency infected with Talaromyces marneffei.

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immune-mediated disease that affects patients with known genetic defects and is increasingly found among those with autoimmune diseases and persistent infections. Talaromyces marneffei (TM) is a human opportunistic fungus that commonly infects immunodeficient or immunosuppressed individuals. Few TM-associated secondary HLH cases resulting from autoimmune deficiency have been reported previously. The current case study describes a pediatric patient hospitalized with recurrent fever and lymphadenopathy. The child had abnormal blood cell classification, and microscopy revealed mature granulocytes that phagocytized fungal spores. It was speculated that the patient was infected with TM. The pathogen was detected earlier than the blood culture and confirmed by metagenomic next-generation sequencing. Whole-exome sequencing revealed that the patient had complex mutations associated with immunodeficiency. This included a mutation in exon 3 of the CD40LG gene, c.346G>A, which may be linked to hyper-IgM syndrome, a primary immunodeficiency disease with immunoglobulin conversion recombination defects that could explain the patient's increased susceptibility to serious opportunistic infections. In addition, a heterozygous frameshift variant, c.820dup (p.Asp274GlyfsTer61), was detected in exon 6 of CARD9, a key gene associated with fungal immune surveillance. After 4 days of fungal treatment, the abnormal blood cell clusters disappeared, but other infections occurred in succession for 6 months after rehabilitation. The patient was followed with the aim of providing subsequent immunotherapy. This study found that infection can trigger HLH in HIV-negative individuals, highlighting the importance of early definitive identification of the causative agent and investigation of potential immunodeficiency.

Sandwich-Structured Flexible PVA/CS@MWCNTs Composite Films with High Thermal Conductivity and Excellent Electrical Insulation.

High thermal conductivity polymer matrix composites have become an urgent need for the thermal management of modern electronic devices. However, increasing the thermal conductivity of polymer-based composites typically results in loss of lightweight, flexibility and electrical insulation. Herein, the polyvinyl alcohol (PVA)/PVA-chitosan-adsorbed multi-walled carbon nanotubes/PVA (PVA/CS@MWCNTs) composite films with a sandwich structure were designed and fabricated by a self-construction strategy inspired by the surface film formation of milk. The obtained film simultaneously possesses high thermal conductivity, electrical insulation, and excellent flexibility. In this particular structure, the uniform intermediate layer of PVA-CS@MWCNTs contributed to improving the thermal conductivity of composite films, and the PVA distributed on both sides of the sandwich structure maintains the electrical insulation of the films (superior electrical resistivity above 1012 Ω·cm). It has been demonstrated that the fillers could be arranged in a horizontal direction during the scraping process. Thus, the obtained composite film exhibited high in-plane thermal conductivity of 5.312 W·m-1·K-1 at fairly low MWCNTs loading of 5 wt%, which increased by about 1190% compared with pure PVA (0.412 W·m-1·K-1). This work effectively realizes the combination of high thermal conductivity and excellent electrical insulation, which could greatly expand the application of polymer-based composite films in the area of thermal management.

Effect of KI Concentration in Correcting Tank on Optical Properties of PVA Polarizing Film.

Polarizer is a key component of the liquid crystal display panel, and the optical properties mainly include transmittance, degree of polarization and chromaticity. Polarizer is made of a multilayer optical film, in which the PVA polarizing film is the core structure for realizing the polarization of the whole polarizer. PVA polarizing film is commonly manufactured through a multi-step craft, including rinsing, dyeing, stretching and correcting. The correction process has a significant impact on the final apparent color and optical properties of the polarizer. In this study, the KI concentration in the correcting tank, ranging from 1% to 3%, was systematically investigated. With the increase in KI concentration, the Raman vibration peak at 160 cm-1 representing I5- ions gradually weakened, while the Raman vibration peak at 110 cm-1 representing I3- ions gradually increased, indicating that the KI in the correcting tank changed the chemical equilibrium of polyiodide ions in PVA. Then abundant chromophore I5- ions were consumed and I3- ions generated, so that the apparent color of PVA polarizing film gradually changed from dark blue to dark gray, and the chromaticity a-value and b-value gradually increased. The change in the concentration of dichroic species (I5- and I3-) in PVA polarizing film had directly affected its transmittance in the visible range. From the UV-Vis transmittance spectrum of PVA polarizing film, when the I5- ions were consumed and I3- ions generated, the transmittance of PVA polarizing film in the region of 675-525 nm wavelength increased gradually while the polarization degree also increased.

Prevalence, serotypes, and antimicrobial resistance of Salmonella isolates from patients with diarrhea in Shenzhen, China.

BACKGROUND: Salmonella is one of the main causative agents of diarrhea which results in substantial disease burden. To determine the prevalence, serotype distribution, and antimicrobial resistance profiles of clinical Salmonella isolates in Shenzhen, a 6-year surveillance study was conducted. RESULTS: A total of 297 (5.7%) Salmonella strains were isolated from stool samples from 5239 patients. Among the 42 serotypes identified, serotype Typhimurium was the most common one which represented 39.7% of the isolates (118), followed by serotype Enteritidis (71, 23.9%), London (12, 4.0%), 4, 5, 12: i: - (11, 3.7%), and Senftenberg (8, 2.7%). A high frequency of resistance was found in ampicillin (70.6%), piperacillin (64.5%), tetracycline (63.5%), and streptomycin (54.3%). Resistance to ampicillin and tetracycline was observed in 95.3% of S. Typhimurium isolates; and nalidixic acid in 93.1% of S. Enteritidis isolates. Resistance to 5 or more antimicrobial agents was found in 78.8% of S. Typhimurium and 69.0% of S. Enteritidis isolates. A decreased susceptibility to ciprofloxacin and levofloxacin was associated with amino acid alteration in gyrA gene. Point mutations without amino acid changes were seen in gyrB, parC, and parE genes. CONCLUSIONS: A broad range of serotypes are responsible for Salmonellosis in Shenzhen, with Enteritidis and Typhimurium being the most common serotypes. The high level of antibiotic resistance is of public health significance and ongoing monitoring combined with rational use of antibiotics are recommended. Point mutations in gyrA gene might play an important role in the resistance to fluoroquinolones.

The etiology of acute meningitis and encephalitis syndromes in a sentinel pediatric hospital, Shenzhen, China.

BACKGROUND: Acute meningitis and encephalitis syndromes (AMES) is a severe neurological infection which causes high case fatality and severe sequelae in children. To determine the etiology of childhood AMES in Shenzhen, a hospital-based study was undertaken. METHODS: A total of 240 cerebrospinal fluid (CSF) samples from 171 children meeting the case definition were included and screened for 12 common causative organisms. The clinical data and conventional testing results were collected and analyzed. Whole genome sequencing was performed on a Neisseria meningitidis isolate. RESULTS: A pathogen was found in 85 (49.7%) cases; Group B Streptococcus (GBS) was detected in 17 cases, Escherichia coli in 15, Streptococcus pneumoniae in 14, enterovirus (EV) in 13, herpes simplex virus (HSV) in 3, N. meningitidis in 1, Haemophilus influenzae in 1, and others in 23. Notably, HSV was found after 43 days of treatment. Twelve GBS and 6 E. coli meningitis were found in neonates aged less than 1 month; 13 pneumococcal meningitis in children aged > 3 months; and 12 EV infections in children aged > 1 year old. The multilocus sequence typing of serogroup B N. meningitidis isolate was ST-3200/CC4821. High resistance rate to tetracycline (75%), penicillin (75%), and trimethoprim/sulfamethoxazole (75%) was found in 4 of S. pneumoniae isolates; clindamycin (100%) and tetracycline (100%) in 9 of GBS; and ampicillin (75%) and trimethoprim/sulfamethoxazole (67%) in 12 of E. coli. CONCLUSIONS: The prevalence of N. meningitidis and JEV was very low and the cases of childhood AMES were mainly caused by other pathogens. GBS and E. coli were the main causative organisms in neonates, while S. pneumoniae and EV were mainly found in older children. HSV could be persistently found in the CSF samples despite of the treatment. A better prevention strategy for GBS, the introduction of pneumococcal vaccine, and incorporation of PCR methods were recommended.

Hepatocyte miR-33a mediates mitochondrial dysfunction and hepatosteatosis by suppressing NDUFA5.

Emerging evidence suggests that microRNAs (miRNAs) are essential for metabolic haemostasis of liver tissues. Among them, miR-33a is supposed to modulate the cholesterol export and fatty acid oxidation, but whether miR-33a involves in the process of fatty liver disease is unclear. To disclose the hypothesis, we utilized miR-33a mimic and antisense to explore their effects in primary hepatocytes or high-fat diet (HFD)-fed mice. Treatment with palmitic acid (PA) or HFD significantly increased the expression of miR-33a in hepatocytes or liver tissues. In primary hepatocytes, miR-33a mimic decreased mitochondrial function, including reduction of ATP production and oxygen consumption, whereas miR-33a inhibition protected PA-induced mitochondrial dysfunction. Interestingly, miR-33a selectively suppressed mitochondrial complex I activity and protein expression, but not other complexes. Through bioinformatics prediction, we found miR-33a directly targeted on the 3'-UTR of NDUFA5. Dual-luciferase reporter analysis further confirmed the direct suppression of miR-33a on NDUFA5 expression. More importantly, administration of miR-33a antisense could effectively restore HFD-induced mitochondrial dysfunction through up-regulation of NDUFA5 levels. Mice treated with miR-33a antisense also exhibited improved liver function and structural disorders under obese status. Taken together, miR-33a was an important mediator of hepatocyte mitochondrial function, and the therapeutic benefits implied miR-33a antisense had the potential clinical application in combating the fatty liver disease.

A novel role of fragile X mental retardation protein in pre-mRNA alternative splicing through RNA-binding protein 14.

Fragile X mental retardation protein (FMRP), an important RNA-binding protein responsible for fragile X syndrome, is involved in posttranscriptional control of gene expression that links with brain development and synaptic functions. Here, we reveal a novel role of FMRP in pre-mRNA alternative splicing, a general event of posttranscriptional regulation. Using co-immunoprecipitation and immunofluorescence assays, we identified that FMRP interacts with an alternative-splicing-associated protein RNA-binding protein 14 (RBM14) in a RNA-dependent fashion, and the two proteins partially colocalize in the nuclei of hippocampal neurons. We show that the relative skipping/inclusion ratio of the micro-exon L in the Protrudin gene and exon 10 in the Tau gene decreased in the hippocampus of Fmr1 knockout (KO) mice. Knockdown of either FMRP or RBM14 alters the relative skipping/inclusion ratio of Protrudin and Tau in cultured Neuro-2a cells, similar to that in the Fmr1 KO mice. Furthermore, overexpression of FMRP leads to an opposite pattern of the splicing, which can be offset by RBM14 knockdown. RNA immunoprecipitation assays indicate that FMRP promotes RBM14's binding to the mRNA targets. In addition, overexpression of the long form of Protrudin or the short form of Tau promotes protrusion growth of the retinoic acid-treated, neuronal-differentiated Neuro-2a cells. Together, these data suggest a novel function of FMRP in the regulation of pre-mRNA alternative splicing through RBM14 that may be associated with normal brain function and FMRP-related neurological disorders.

Involvement of FMRP in Primary MicroRNA Processing via Enhancing Drosha Translation.

Fragile X mental retardation protein (FMRP), associated with fragile X syndrome, is known as an RNA-binding protein to regulate gene expression at post-transcriptional level in the brain. FMRP is also involved in microRNA (miRNA) biogenesis during the process of precursor miRNA (pre-miRNA) into mature miRNA. However, there is no description of the effect of FMRP on primary miRNA (pri-miRNA) processing. Here, we uncover a novel role of FMRP in pri-miRNA processing via controlling Drosha translation. We show that the expression of DROSHA protein, instead of its messenger RNA (mRNA) transcripts, is downregulated in both the hippocampus of Fmr1-knockout mice and the FMRP-knockdown Neuro-2a cells. Overexpression or knockdown FMRP does not alter Drosha mRNA stability. Immunoprecipitation and polysome analyses demonstrate that FMRP binds to the Drosha mRNA and enhances its translation. Additionally, we show that loss of FMRP in Fmr1-deficient mice results in the accumulation of three in six analyzed pri-miRNAs and the reduction of the corresponding pre-miRNAs and mature miRNAs. Thus, our data suggest that FMRP is involved in pri-miRNA processing via enhancing DROSHA expression that may play an important role in fragile X syndrome.