Prevalence and molecular characterization of parechovirus A in children with acute gastroenteritis in Shenzhen, 2016-2018.

Parechovirus A (PeV-A), which causes a wide variety of diseases, is prevalent among young children. However, little is currently known about PeV-A infections in children with acute gastroenteritis in mainland China. In this study, we investigated the molecular epidemiology of acute gastroenteritis in Shenzhen, southern China, with an emphasis on PeV-A infections. A total of 1220 stool specimens from 1220 outpatient children under 5 years old with acute gastroenteritis were collected from January 2016 to December 2018. Viral RNA was detected by a real-time RT-PCR and PCR method. The PeV-A isolates were genotyped by sequencing the VP3/VP1 region. Of 1220 specimens, 148 (12.1%) were positive for PeV-A. The predominant genotype was PeV-A 1B (68.9%), followed by PeV-A 4 (12.2%), PeV-A 14 (6.1%), PeV-A 1A (5.4%), PeV-A 6 (2.7%), PeV-A 3 (2.7%) and PeV-A 5 (2.0%). It was found that 68.2% of PeV-A infections occurred in the summer and rainy months (June to September) in southern China. The majority of PeV-A-positive patients (97.3%) were younger than 24 months old. PeV-A coinfection with norovirus, rotavirus, astrovirus and adenovirus was found in thirty specimens (30/148, 20.3%), five specimens (5/148, 3.4%), five specimens (5/148, 3.4%), and two specimens (2/148, 1.4%), respectively. Coinfections with more than one other enteric virus were not observed in any of the PeV-A-positive specimens. Phylogenetic analysis revealed that the PeV-A isolates from Shenzhen were closely related to each other and to strains circulating in China, suggesting endemic circulation of PeV-A in China. The results of this study indicate that PeV-A is one of important pathogens of acute gastroenteritis in young children and that coinfection is a possible mode of PeV-A infection. PeV-A associated with acute gastroenteritis exhibited high genotypic diversity in Shenzhen, southern China.

Identification of cross-linked peptides from complex samples.

We have developed pLink, software for data analysis of cross-linked proteins coupled with mass-spectrometry analysis. pLink reliably estimates false discovery rate in cross-link identification and is compatible with multiple homo- or hetero-bifunctional cross-linkers. We validated the program with proteins of known structures, and we further tested it on protein complexes, crude immunoprecipitates and whole-cell lysates. We show that it is a robust tool for protein-structure and protein-protein-interaction studies.

The association between hemoglobin at admission and mortality of older patients with hip fracture: a mean 3-year follow-up cohort study.

BACKGROUND: Hip fracture patients often have a large drop in hemoglobin (Hgb) concentration that is associated with the initial trauma. However, there is no study of a correlation between Hgb concentration at admission and short-term mortality. Thus, we evaluated a possible linear and nonlinear association between Hgb and mortalityfor older patients with hip fracture. METHODS: Consecutive older patients who had hip fractures were screened between January 2015 and September 2019. Demographic and clinical characteristics were collected. Linear and nonlinear multivariate Cox regression models were used to identify association between Hgb at admission and mortality. All analyses were performed with EmpowerStats and R software. RESULTS: Two thousand five hundred eighty-nine patients were included in the study. There were 849 men and 1740 women. The mean age was 79.6 ± 6.8 years. The mean follow-up was 39.0 months. Nine hundred seven (35.0%) patients died for all-cause reasons. The mean Hgb at admission was 11.07 ± 1.95 g/dL. Linear multivariate Cox regression models showed Hgb at admission was associated with mortality ([Hazard Ratio] HR 0.91, 95% CI 0.87-0.95, P < 0.0001) after adjusting for confounding factors. However, the linear association was unstable, and nonlinearity was found between Hgb at admission and mortality. The Hgb concentration of 9.8 g/dL was an inflection point. A Hgb at admission < 9.8 g/dL was associated with mortality (HR 0.81, 95% CI 0.74-0.89, P < 0.0001), whereas > 9.8 g/dL was not a risk factor for mortality (HR 0.98, 95% CI 0.92-1.04, P = 0.4730). CONCLUSIONS: The Hgb concentration at admission was nonlinearly associated with mortality of older patients with hip fracture, and Hgb at admission < 9.8 g/dL was a risk predictor of 3-year mortality. RESEARCH REGISTRATION: ChiCTR2200057323.

Speeding up tandem mass spectrometry-based database searching by longest common prefix.

BACKGROUND: Tandem mass spectrometry-based database searching has become an important technology for peptide and protein identification. One of the key challenges in database searching is the remarkable increase in computational demand, brought about by the expansion of protein databases, semi- or non-specific enzymatic digestion, post-translational modifications and other factors. Some software tools choose peptide indexing to accelerate processing. However, peptide indexing requires a large amount of time and space for construction, especially for the non-specific digestion. Additionally, it is not flexible to use. RESULTS: We developed an algorithm based on the longest common prefix (ABLCP) to efficiently organize a protein sequence database. The longest common prefix is a data structure that is always coupled to the suffix array. It eliminates redundant candidate peptides in databases and reduces the corresponding peptide-spectrum matching times, thereby decreasing the identification time. This algorithm is based on the property of the longest common prefix. Even enzymatic digestion poses a challenge to this property, but some adjustments can be made to this algorithm to ensure that no candidate peptides are omitted. Compared with peptide indexing, ABLCP requires much less time and space for construction and is subject to fewer restrictions. CONCLUSIONS: The ABLCP algorithm can help to improve data analysis efficiency. A software tool implementing this algorithm is available at http://pfind.ict.ac.cn/pfind2dot5/index.htm.

Preparation of an electrospun tubular PU/GE nanofiber membrane for high flux oil/water separation.

A simple, tubular structure polyurethane/graphene (PU/GE) nanofiber membrane for continuous oil/water separation was prepared using the following strategies: a polyester (PET) fiber braided tube was used for reinforcement, stearic acid (SA) was used to assist GE dispersion, and a PU solution containing GE was used to cover the outer layer of the PET fiber braided tube using the electrospinning method. Specifically, the PU/GE nanofiber membrane has a multi-branched structure. The tubular braid reinforced (TBR) PU/GE nanofiber membrane was characterized using field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), confocal scanning microscopy (CSM) and capillary flow porometry. The contact angle results showed that the TBR PU/GE nanofiber membrane had good hydrophobic and lipophilic properties. The obtained membranes had good oil/water selectivity for oil-water separation (with a separation efficiency up to 99%). In addition, the optimized membrane can be effectively employed to separate a surfactant-stabilized water-in-oil emulsion with a separation efficiency up to 90% and a high permeate flux (137.5 L m-2 h-1). Our TBR PU/GE nanofiber membrane is therefore a desirable material for the highly efficient separation of water-in-oil emulsions, and shows broad application prospects in the field of oil/water separation.

[Characterization of the orientation of polymer material by non-polarized raman laser light spectroscopy].

The non-polarized Raman laser light was used to investigate the anisotropic polymers including polypropylene fiber, nylon 6 flat fiber, and polyethylene pipe. The Raman spectra of the same samples with different location relative to the incident direction of laser beam show obvious differences. The present result extends the application of Raman spectroscopy to the characterization of oriented polymers samples.