[Analysis of non-bacterial respiratory pathogens in children in Ningbo City from 2019 to 2021].

Objective: To investigate the distribution characteristics of respiratory non-bacterial pathogens in children in Ningbo from 2019 to 2021. Methods: A retrospective analysis was performed on 23 733 children with respiratory tract infection who visited the department of pediatrics of Ningbo Women and Children's Hospital from July 2019 to December 2021. There were 13 509 males (56.92%) and 10 224 females (43.08%), with an age range of 1 day to 18 years old. There were 981 cases in the neonatal group (younger than 1 month old), 5 880 cases in the infant group (1 month to younger than 1 year old), 6 552 cases in the toddler group (1 to younger than 3 years old), 7 638 cases in the preschool group (3 to younger than 7 years old), and 2 682 cases in the school-age group (7 to 18 years old). Thirteen respiratory pathogens were detected by multiple polymerase chain reaction (PCR) based on capillary electrophoresis, and SPSS 23.0 software was used for statistical analysis of the results, the count data were expressed as percentages, and the χ2 test was used for comparison between groups. Results: Of the 23 733 specimens, 13 330 were positive for respiratory pathogens, with a total positive rate of 56.17%. The positive rates of human rhinovirus (HRV) 24.05% (5 707/23 733), human respiratory syncytial virus (HRSV) 10.45% (2 480/2 3733) and mycoplasma pneumoniae (Mp) 7.03% (1 668/23 733) were in the first three. The positive rates of pathogens in the male and female children were 57.47% (7 763/13 509) and 54.45% (5 567/10 224), respectively, and the difference was statistically significant (χ2=21.488, P<0.001). The positive rates in the neonatal group, infant group, toddler group, preschool group, and school-age group were 31.80% (312/981), 54.71% (3 217/5 880), 63.23% (4 143/6 552), 59.83% (4 570/7 638), 40.57% (1 088/2 682), respectively, and the difference among the groups was statistically significant (χ2=681.225, P<0.001). The single infection rate was 47.43% (11 256/23 733), the mixed infection rate of two or more pathogens was 8.74% (2 074/23 733), most of which were mixed infections of two pathogens. HRV, HADV, HCOV, Ch disseminated in the whole year. HRSV, HMPV, Boca, HPIV occurred mostly in fall and winter. The positive rates of FluA, FluB, Mp were at a low level after the corona virus disease 2019 (COVID-19) epidemic (2020 and 2021). The positive rates of FluA, H1N1, H3N2, FluB, HADV, Mp in 2020 were significantly lower than in 2019 (P<0.05). The positive rates of HPIV, HRV, HCOV, Ch in 2020 were significantly higher than in 2019 (P<0.05). The positive rates of FluA, H1N1, H3N2, HPIV, HCOV, Mp, Ch in 2021 were significantly lower than in 2020 (P<0.05). The positive rates of Boca, HMPV, HRSV in 2021 were significantly higher than in 2020 (P<0.05). Conclusion: From 2019 to 2021, the main non-bacterial respiratory pathogens of children in Ningbo City were Mp and HRV, and the detection rates of respiratory pathogens varied among different ages, seasons and genders.

Chitosan nanofibers from an easily electrospinnable UHMWPEO-doped chitosan solution system.

Conversion of natural biopolymer chitosan into nanofibers through electrospinning has significant usefulness in various biomedical applications, in particular, for constructing a biomimetic and bioactive nanofibrous artificial extracellular matrix for engineering various tissues. Here, we show that introduction of an ultrahigh-molecular-weight poly(ethylene oxide) (UHMWPEO) into aqueous chitosan solutions remarkably enhances the formation of chitosan nanofibrous structure and leads to much lower loading of the water soluble fiber-forming aiding agent of PEO down to 5 wt % as compared to previous high PEO loadings in the electrospun chitosan nanofibers. The excellent electrospinnability of the current formulation renders electrospinning of natural biopolymer chitosan a robust process for large-scale production of practically applicable nanofibrous structures.

Zirconia toughened alumina ceramic foams for potential bone graft applications: fabrication, bioactivation, and cellular responses.

Zirconia toughened alumina (ZTA) has been regarded as the next generation orthopedic graft material due to its excellent mechanical properties and biocompatibility. Porous ZTA ceramics with good interconnectivity can potentially be used as bone grafts for load-bearing applications. In this work, three-dimensional (3D) interconnected porous ZTA ceramics were fabricated using a direct foaming method with egg white protein as binder and foaming agent. The results showed that the porous ZTA ceramics possessed a bimodal pore size distribution. Their mechanical properties were comparable to those of cancellous bone. Due to the bio-inertness of alumina and zirconia ceramics, surface bioactivation of the ZTA foams was carried out in order to improve their bioactivity. A simple NaOH soaking method was employed to change the surface chemistry of ZTA through hydroxylation. Treated samples were tested by conducting osteoblast-like cell culture in vitro. Improvement on cells response was observed and the strength of porous ZTA has not been deteriorated after the NaOH treatment. The porous 'bioactivated' ZTA ceramics produced here could be potentially used as non-degradable bone grafts for load-bearing applications.

Evaluation of electrospun PCL/gelatin nanofibrous scaffold for wound healing and layered dermal reconstitution.

The current design requirement for a tissue engineering skin substitute is that of a biodegradable scaffold through which fibroblasts can migrate and populate. This artificial "dermal layer" needs to adhere to and integrate with the wound, which is not always successful for the current artificial dermal analogues available. The high cost of these artificial dermal analogues also makes their application prohibitive both to surgeons and patients. We propose a cost-effective composite consisting of a nanofibrous scaffold directly electrospun onto a polyurethane dressing (Tegaderm, 3M Medical) - which we call the Tegaderm-nanofiber (TG-NF) construct - for dermal wound healing. Cell culture is performed on both sides of the nanofibrous scaffold and tested for fibroblast adhesion and proliferation. It is hoped that these studies will result in a fibroblast-populated three-dimensional dermal analogue that is feasible for layered applications to build up thickness of dermis prior to re-epithelialization. Results obtained in this study suggest that both the TG-NF construct and dual-sided fibroblast-populated nanofiber construct achieved significant cell adhesion, growth and proliferation. This is a successful first step for the nanofiber construct in establishing itself as a suitable three-dimensional scaffold for autogenous fibroblast populations, and providing great potential in the treatment of dermal wounds through layered application.

Improved biological performance of magnesium by micro-arc oxidation.

Magnesium and its alloys have recently been used in the development of lightweight, biodegradable implant materials. However, the corrosion properties of magnesium limit its clinical application. The purpose of this study was to comprehensively evaluate the degradation behavior and biomechanical properties of magnesium materials treated with micro-arc oxidation (MAO), which is a new promising surface treatment for developing corrosion resistance in magnesium, and to provide a theoretical basis for its further optimization and clinical application. The degradation behavior of MAO-treated magnesium was studied systematically by immersion and electrochemical tests, and its biomechanical performance when exposed to simulated body fluids was evaluated by tensile tests. In addition, the cell toxicity of MAO-treated magnesium samples during the corrosion process was evaluated, and its biocompatibility was investigated under in vivo conditions. The results of this study showed that the oxide coating layers could elevate the corrosion potential of magnesium and reduce its degradation rate. In addition, the MAO-coated sample showed no cytotoxicity and more new bone was formed around it during in vivo degradation. MAO treatment could effectively enhance the corrosion resistance of the magnesium specimen and help to keep its original mechanical properties. The MAO-coated magnesium material had good cytocompatibility and biocompatibility. This technique has an advantage for developing novel implant materials and may potentially be used for future clinical applications.

Tissue response to commercial silicone and polyurethane elastomers after different sterilization procedures.

Two different commercial polymeric materials, a silicone and a polyurethane (PUR), were studied with regard to correlations between the chemical and physical compositions of the polymer surfaces and the biological response on implantation. Test specimens of the materials were manufactured according to standard procedures. The specimens were implanted in rats for 10 and 90 days. Before implantation the polymers were sterilized in three different ways, namely, beta irradiation, ethylene oxide sterilization and steam sterilization. The polymers were characterized before and after the implantation with respect to the chemical composition and the morphology of the surfaces. After implantation the biological response was evaluated by counting numbers of macrophages, giant cells, fibroblasts and other cells present at the surfaces. The thickness of the fibrous capsule surrounding the test specimens was measured at the thickest and thinnest parts. PUR surfaces showed signs of degradation already after sterilization and after 10 to 90 days of implantation, pits and cracks appeared, especially in the ethylene oxide sterilized samples. However, differences in the biological responses were small and independent of the sterilization method. After 10 days of implantation the capsule thickness and the amounts of cell material adhering at the surfaces were different, and it appears that the silicone rubber induces more tissue response than PUR. The differences in the early tissue response evened out after 90 days implantation time and a steady state situation evolved, which was similar for the silicone and the polyurethane.

[Establishment of an animal model of Capillaria hepatica].

OBJECTIVE: To establish an animal model of Capillaria hepatica. METHOD: Sixteen rats and two cats were infected with the embryo eggs of Capillaria hepatica through mouth. RESULTS: Of 16 infected rats, 2 were negative, 14 were positive with Capillaria hepatica. 2 cats were negative. CONCLUSION: Rats could be used as an animal model of Capillaria hepatica.

An animal experimental study of porous magnesium scaffold degradation and osteogenesis.

Our objective was to observe the biodegradable and osteogenic properties of magnesium scaffolding under in vivo conditions. Twelve 6-month-old male New Zealand white rabbits were randomly divided into two groups. The chosen operation site was the femoral condyle on the right side. The experimental group was implanted with porous magnesium scaffolds, while the control group was implanted with hydroxyapatite scaffolds. X-ray and blood tests, which included serum magnesium, alanine aminotransferase (ALT), creatinine (CREA), and blood urea nitrogen (BUN) were performed serially at 1, 2, and 3 weeks, and 1, 2, and 3 months. All rabbits were killed 3 months postoperatively, and the heart, kidney, spleen, and liver were analyzed with hematoxylin and eosin (HE) staining. The bone samples were subjected to microcomputed tomography scanning (micro-CT) and hard tissue biopsy. SPSS 13.0 (USA) was used for data analysis, and values of P<0.05 were considered to be significant. Bubbles appeared in the X-ray of the experimental group after 2 weeks, whereas there was no gas in the control group. There were no statistical differences for the serum magnesium concentrations, ALT, BUN, and CREA between the two groups (P>0.05). All HE-stained slices were normal, which suggested good biocompatibility of the scaffold. Micro-CT showed that magnesium scaffolds degraded mainly from the outside to inside, and new bone was ingrown following the degradation of magnesium scaffolds. The hydroxyapatite scaffold was not degraded and had fewer osteoblasts scattered on its surface. There was a significant difference in the new bone formation and scaffold bioabsorption between the two groups (9.29 ± 1.27 vs 1.40 ± 0.49 and 7.80 ± 0.50 vs 0.00 ± 0.00 mm3, respectively; P<0.05). The magnesium scaffold performed well in degradation and osteogenesis, and is a promising material for orthopedics.

An animal experimental study of porous magnesium scaffold degradation and osteogenesis

Our objective was to observe the biodegradable and osteogenic properties of magnesium scaffolding under in vivo conditions. Twelve 6-month-old male New Zealand white rabbits were randomly divided into two groups. The chosen operation site was the femoral condyle on the right side. The experimental group was implanted with porous magnesium scaffolds, while the control group was implanted with hydroxyapatite scaffolds. X-ray and blood tests, which included serum magnesium, alanine aminotransferase (ALT), creatinine (CREA), and blood urea nitrogen (BUN) were performed serially at 1, 2, and 3 weeks, and 1, 2, and 3 months. All rabbits were killed 3 months postoperatively, and the heart, kidney, spleen, and liver were analyzed with hematoxylin and eosin (HE) staining. The bone samples were subjected to microcomputed tomography scanning (micro-CT) and hard tissue biopsy. SPSS 13.0 (USA) was used for data analysis, and values of P<0.05 were considered to be significant. Bubbles appeared in the X-ray of the experimental group after 2 weeks, whereas there was no gas in the control group. There were no statistical differences for the serum magnesium concentrations, ALT, BUN, and CREA between the two groups (P>0.05). All HE-stained slices were normal, which suggested good biocompatibility of the scaffold. Micro-CT showed that magnesium scaffolds degraded mainly from the outside to inside, and new bone was ingrown following the degradation of magnesium scaffolds. The hydroxyapatite scaffold was not degraded and had fewer osteoblasts scattered on its surface. There was a significant difference in the new bone formation and scaffold bioabsorption between the two groups (9.29±1.27 vs 1.40±0.49 and 7.80±0.50 vs 0.00±0.00 mm3, respectively; P<0.05). The magnesium scaffold performed well in degradation and osteogenesis, and is a promising material for orthopedics.

Biomimetic and bioactive nanofibrous scaffolds from electrospun composite nanofibers.

Electrospinning is an enabling technology that can architecturally (in terms of geometry, morphology or topography) and biochemically fabricate engineered cellular scaffolds that mimic the native extracellular matrix (ECM). This is especially important and forms one of the essential paradigms in the area of tissue engineering. While biomimesis of the physical dimensions of native ECM's major constituents (eg, collagen) is no longer a fabrication-related challenge in tissue engineering research, conveying bioactivity to electrospun nanofibrous structures will determine the efficiency of utilizing electrospun nanofibers for regenerating biologically functional tissues. This can certainly be achieved through developing composite nanofibers. This article gives a brief overview on the current development and application status of employing electrospun composite nanofibers for constructing biomimetic and bioactive tissue scaffolds. Considering that composites consist of at least two material components and phases, this review details three different configurations of nanofibrous composite structures by using hybridizing basic binary material systems as example. These are components blended composite nanofiber, core-shell structured composite nanofiber, and nanofibrous mingled structure.

Coaxial electrospinning of (fluorescein isothiocyanate-conjugated bovine serum albumin)-encapsulated poly(epsilon-caprolactone) nanofibers for sustained release.

As an aim toward developing biologically mimetic and functional nanofiber-based tissue engineering scaffolds, we demonstrated the encapsulation of a model protein, fluorescein isothiocyanate-conjugated bovine serum albumin (fitcBSA), along with a water-soluble polymer, poly(ethylene glycol) (PEG), within the biodegradable poly(epsilon-caprolactone) (PCL) nanofibers using a coaxial electrospinning technique. By variation of the inner flow rates from 0.2 to 0.6 mL/h with a constant outer flow rate of 1.8 mL/h, fitcBSA loadings of 0.85-2.17 mg/g of nanofibrous membranes were prepared. Variation of flow rates also resulted in increases of fiber sizes from ca. 270 nm to 380 nm. The encapsulation of fitcBSA/PEG within PCL was subsequently characterized by laser confocal scanning microscopy, transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analysis. In vitro release studies were conducted to evaluate sustained release potential of the core-sheath-structured composite nanofiber PCL-r-fitcBSA/PEG. As a negative control, composite nanofiber PCL/fitcBSA/PEG blend was prepared from a normal electrospinning method. It was found that core-sheath nanofibers PCL-r-fitcBSA/PEG pronouncedly alleviated the initial burst release for higher protein loading and gave better sustainability compared to that of PCL/fitcBSA/PEG nanofibers. The present study would provide a basis for further design and optimization of processing conditions to control the nanostructure of core-sheath composite nanofibers and ultimately achieve desired release kinetics of bioactive proteins (e.g., growth factors) for practical tissue engineering applications.

Characterization of the surface biocompatibility of the electrospun PCL-collagen nanofibers using fibroblasts.

The effect of nanofiber surface coatings on the cell's proliferation behavior was studied. Individually collagen-coated poly(epsilon-caprolactone) (PCL) nanofibers (i.e., Collagen-r-PCL in the form of a core-shell structure) were prepared by a coaxial electrospinning technique. A roughly collagen-coated PCL nanofibrous matrix was also prepared by soaking the PCL matrix in a 10 mg/mL collagen solution overnight. These two types of coated nanofibers were then used to investigate differences in biological responses in terms of proliferation and cell morphology of human dermal fibroblasts (HDF). It was found that coatings of collagen on PCL nanofibrous matrix definitely favored cells proliferation, and the efficiency is coating means dependent. As compared to PCL, the HDF density on the Collagen-r-PCL nanofiber membrane almost increased linearly by 19.5% (2 days), 22.9% (4 days), and 31.8% (6 days). In contrast, the roughly collagen-coated PCL increased only by 5.5% (2 days), 11.0% (4 days), and 21.0% (6 days). SEM observation indicated that the Collagen-r-PCL nanofibers encouraged cell migration inside the scaffolds. These findings suggest that the Collagen-r-PCL nanofibers can be used as novel functional biomimetic nanofibers toward achieving excellent integration between cells and scaffolds for tissue engineering applications.

Orientation of the cytoplasmically made subunits of beef heart cytochrome c oxidase determined by protease digestion and antibody binding experiments.

The topology of several of the cytoplasmically made subunits of beef heart cytochrome c oxidase has been determined by protease digestion of oriented membrane preparations, using subunit-specific antibodies to identify cleavage products. Reconstituted vesicles of cytochrome c oxidase and asolectin were used as a vesicle preparation with the C domain of the enzyme available for protease digestion. Submitochondrial particles were used as vesicles with the M domain outermost. Trypsin and/or proteinase K cleaved polypeptides CIV, ASA, AED, STA, and IHQ. Cleavage of CIV, STA, and IHQ was from the M domains only and involved the removal of a fragment from the N-terminus in each case. Polypeptide AED was cleaved from the C side in the N-terminal part, while ASA was cleaved from both the C and M domains. Polypeptide fragments were electroblotted from polyacrylamide gels onto derivatized glass paper and sites of proteolytic cleavage determined by N-terminal sequence analysis.

[Studies on lignocellulolytic enzymes production and biomass degradation of Pleurotus sp2 and Trametes gallica in wheat straw cultures].

Pleurotus sp2 and Trametes gallica were selected in this assay because of their high activities of lignocellulolytic enzymes and the enzyme peaks appeared at the early stage of liquid state fermentation. Solid state fermentation was also investigated for their abilities and behaviors of enzyme-production. The capabilities and characteristics of the two strains in degrading biomass were studied. When Pleurotus sp2 was incubated in wheat straw powder containing the liquid medium of low-nitrogen, no-carbon and high inorganic salt, the activities of MnP and Lac reached the peaks on the tenth day, but the activities of hemicellulases reached the peak on the 40th day. Pleurotus sp2 caused 17.6% of biomass loss. When T. gallica was incubated in wheat straw powder containing the liquid medium of hlig-nitrogen, or low-nitrogen, no-carbon and high inorganic salt, the activities of MnP reached the peaks on the tenth day, the lac and hemicelluloses on the 40th day, and the lignin peroxidases reached the peaks on the 50th day, and it caused more than 64% of biomass loss. Among them the hemicellulose was degraded by 71.96%, and the cellulose 66.21%. T. gallica was very capable of degrading lignin of wheat straw and caused 34.37% loss during 20 days, 46. 71% loss during 30 days and 70.14% loss during 60 days. It was interesting that T. gallica degraded lignin preferentially with respect to cellulose, which was very beneficial to biopulping of paper industry.