Protective role of α2-macroglobulin against jaw osteoradionecrosis in a preclinical rat model.

OBJECTIVE: We have previously demonstrated the effect of alpha-2-macroglobulin (α2M) in the remediation of radiation-induced cellular damage. Here, we investigated the protective effects of α2M in a preclinical rat model of jaw osteoradionecrosis (ORN). METHODS: Eighteen rats were divided randomly into three groups: the control group, the radiation therapy (RT) alone group, and the radiated mandibles pretreated with α2M (α2M + RT) group. One month after radiation, all left molar teeth were extracted. After another 3 months, the animals were sacrificed and body weight, histopathology, microcomputed tomography and immunofluorescence were evaluated in all groups. RESULTS: The RT group showed serious alopecia, bone exposure, inflammation, necrosis, fibrosis, and the absence of new bone formation within the socket. The α2M + RT group exhibited less alopecia than the RT group and slight inflammation and fibrosis in the bone marrow cavity. The cortical bone was similar to normal bone tissue. Interestingly, compared with RT group, serum superoxide dismutase levels in the α2M + RT group increased at the 1th day (P = 0.037), 14th day (P = 0.012), while reactive oxygen species levels clearly decreased at the 1th day (P< 0.001), 14th day (P = 0.007), and 28th day (P = 0.013). CONCLUSIONS: A clinically translational model of jaw ORN was successfully established and the application of α2M prior to radiation protected the bone from being injured by the radiation, possibly related to oxidative stress.

The co-pyrolysis of waste urea-formaldehyde resin with pine sawdust: co-pyrolysis behavior, pyrocarbon and its adsorption performance for Cr (VI).

Urea-formaldehyde (UF) resin is difficult to degrade and classified as hazardous organic waste. To address this concern, the co-pyrolysis behavior of UF resin with pine sawdust (PS) was studied, and the adsorption properties of pyrocarbon were evaluated with Cr (VI). Thermogravimetric analysis revealed that adding a small amount of PS can improve the pyrolysis behavior of UF resin. Based on the Flynn Wall Ozawa (FWO) method, the kinetics and activation energy values were estimated. It was observed that when the amount of UF resin exceeded twice that of PS, the activation energy of the reaction decreased, and they acted synergistically. The characterization of pyrocarbon samples showed that the specific surface area increased with the increase of temperature, while the content of functional groups showed the opposite trend. Intermittent adsorption experiments showed that 5UF + PS400 achieved 95% removal of 50 mg/L Cr (VI) at 0.6 g/L dosage and at pH 2. The adsorption process was consistent with the Langmuir isotherm and pseudo-second-order kinetics, and the maximum adsorption was 143.66 mg/g at 30 ℃. Furthermore, the adsorption process consisted of electrostatic adsorption, chelation, and redox reaction. Overall, this study provides a useful reference for the co-pyrolysis of UF resin and the adsorption capacity of pyrocarbon.

Preparation, characterization, and removal of nitrate from water using vacant polyoxometalate/TiO2 composites.

Due to the rapid development of industry and agriculture, nitrate pollution in groundwater has been continuously increasing. NO3-N is a chemically stable nitrogen species and is quite difficult to remove. In this study, using heteropoly silicotungstate K8[α-SiW11O39] and Cu2+ as the active components, SiW11 and Cu2+ were loaded onto TiO2 by a sol-gel method to prepare a composite photocatalyst SiW11/TiO2/Cu. The photocatalytic reduction of dissolved NO3-N was subsequently performed using SiW11/TiO2/Cu under UV irradiation, and the influence of different experimental parameters on the photocatalytic performance was investigated. The mechanism of NO3-N reduction by the composite catalyst was also investigated. Free radicals existing within the system were detected by ESR spectroscopy, and the results indicated that CO2- anion free-radicals were generated by the reaction of photogenerated holes and formic acid (HCOOH). At a SiW11/TiO2/Cu dose of 1.2 g L-1 and in the presence of HCOOH as a hole scavenger, the proposed composite catalytically reduced NO3-N anddemonstrated significantadvantages in terms of its photocatalytic activity in comparison with pure TiO2. In particular, the removal efficiency of NO3-N and the selectivity of nitrogen achieved a maximum of 96% and 77%, respectively.

Characterization of TiO2 and an as-prepared TiO2/SiO2 composite and their photocatalytic performance for the reduction of low-concentration N-NO3- in water.

Excessive N-NO3- water pollution has become a widespread and serious problem that threatens human and ecosystem health. Here, a TiO2/SiO2 composite photocatalyst was prepared via the sol-gel/hydrothermal method. TiO2 and TiO2/SiO2 were characterized by X-ray diffraction (XRD), UV-Vis differential reflectance spectroscopy (DRS), Fourier infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS). Afterward, the photocatalytic performance of TiO2 and TiO2/SiO2 to reduce low nitrate concentrations (30 mgN L-1) under UV light was evaluated and the effects of different factors on this process were investigated, after which the reaction conditions were optimized. Removal rates of up to 99.93% were achieved at a hole scavenger (formic acid) concentration of 0.6 mL L-1, a CO2 flow rate of 0.1 m3 h-1, and a TiO2 concentration of 0.9 g L-1. In contrast, TiO2/SiO2 at a 1.4 g L-1 concentration and a TiO2 load rate of 40% achieved a removal rate of 83.48%, but with more than 98% of nitrogen generation rate. NO2- and NH4+ were the minor products, whereas N2 was the main product.

Factors influencing parents' willingness to vaccinate their preschool children against COVID-19: Results from the mixed-method study in China.

During the COVID-19 pandemic, little is known about parental hesitancy to receive the COVID-19 vaccine for preschool children who are the potential vaccinated population in the future. The purpose of this mixed-method study was to explore the factors influencing Chinese parents' decision to vaccinate their children aged 3-6 years old against COVID-19. In July 2021, we conducted semi-structured interviews (n = 19) and a cross-sectional survey (n = 2605) with parents of kindergarten children in an urban-rural combination pilot area in China. According to the qualitative study, most parents were hesitant to vaccinate their children with the COVID-19 vaccine. In the quantitative study, we found that three-fifths of 2605 participants were unwilling to vaccinate their children against COVID-19. Furthermore, the main predictors of parents' intention to vaccinate their children were fathers, lower level of education, and positive attitudes toward vaccination. Based on our findings, targeted health education techniques may be able to boost childhood COVID-19 immunization rates.

Molecular epidemiology and clinical features of hand, foot and mouth disease requiring hospitalization after the use of enterovirus A71 inactivated vaccine in chengdu, China, 2017-2022: a descriptive study.

Three inactivated enterovirus A71 (EV-A71) vaccines have been widely vaccinated among children in the targeted age group in mainland China since mid-2016. However, comprehensive virological surveillance of hand, foot and mouth disease (HFMD) over multiple years after the use of EV-A71 vaccines has rarely been conducted. Using long-term data extracted from the Public Health and Clinical Center of Chengdu, we described the clinical, aetiological, and epidemiological characteristics of HFMD inpatients after the use of EV-A71 vaccines from 2017 through 2022. A total of 5115 patients were selected for analysis with a male-to-female ratio of 1.63:1 and were mostly under 5 years of age (97.6%). Among these cases, 4.3% presented with severe symptoms, and 4.1% of severe cases experienced significant complications. EV-A71 was no longer the major serotype for laboratory-confirmed HFMD, responsible for 15.6% of severe cases and 1.2% of mild cases. A significant downwards trend of EV-A71 infections was observed after the use of EV-A71 vaccines (P for trend < 0.001). Coxsackievirus A6 was the predominant pathogen, accounting for 63.5% of mild cases and 36.2% of severe cases. Coxsackievirus A10 (CV-A10) and A16 were sporadically detected, and an upwards trend was observed in the proportion of CV-A10 infections. This study provides baseline molecular epidemiology for the evaluation of EV-A71 vaccination impact and potential serotype replacement based on HFMD inpatients. Additional nationwide and population-based epidemiologic and serologic studies are essential to elucidate HFMD dynamics after the use of EV-A71 vaccines, and to inform public health authorities to introduce optimized intervention strategies.

Synthesis of polyoxometalates (POM)/TiO2/Cu and removal of nitrate nitrogen in water by photocatalysis.

Nitrate nitrogen is one of the vital issues needed to be addressed in the water purification process utilizing groundwater as a drinking water source. In this study, a sandwich-type polyoxometalate Na [α-SiW9O34] has been synthesized and SiW9/TiO2/Cu composite has been prepared by sol-gel method. Samples have been characterized by XRD, BET, FTIR, SEM, ED-Mapping, UV-Vis, XPS. The catalytic reduction of nitrate was performed in the presence of SiW9/TiO2/Cu composite as photocatalyst. The effects of catalyst loading, initial nitrate concentration, sandwich-type polyoxometalate loading, dissolved O2, and concentration of formic acid on nitrate removal have been investigated. The results showed that the prepared composite catalyst had better photocatalytic activity than the TiO2. 76.53% of nitrate removal with 82.09% of N2 selectivity was obtained under the following conditions: catalyst dosage 0.8 g/L, initial nitrate concentration of 30 mg/L, SiW9/Cu loading percentage of 10%, 30 mmol/L of formic acid, in presence of N2, and 6 h reaction time.

Preparation and characterization of a copper phosphotungstate/titanium dioxide (Cu-H3PW12O40/TiO2) composite and the photocatalytic oxidation of high-concentration ammonia nitrogen.

Currently, the majority of wastewater with a high concentration of ammonia nitrogen (NH4+/NH3) is treated using biological methods, which have poor biodegradability and low removal efficiency. In this paper, a composite photocatalyst of copper phosphotungstate/titanium dioxide (Cu-H3PW12O40/TiO2) was prepared by sol-gel hydrothermal synthesis, and the composite catalyst was characterized by X-ray diffraction (XRD), UV-vis-diffuse reflectance spectroscopy (UV-VIS-DRS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS)、scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). The photocatalytic oxidation of a high-concentration NH4+/NH3 solution was carried out under ultraviolet (UV) light to explore the effects of different influencing factors on the photocatalytic effect and to optimize the reaction conditions. The prepared composite catalyst exhibited higher photocatalytic activity than that of TiO2. When the initial concentration of the solution was 300 mg·L-1, the initial pH was 11, the catalyst concentration was 1.5 g·L-1, the loading level of Cu-H3PW12O40 was 40%, and the aeration rate was 1.5 L·min-1, the removal rate of NH4+/NH3 by the composite photocatalyst could reach >80%. Very little NO2- and NO3- were produced, and N2 was the main product.

Effect of α2­macroglobulin in the early stage of jaw osteoradionecrosis.

Advanced osteoradionecrosis (ORN) is one of the most serious complications in patients with head and neck cancer, resulting in poor prognosis. Numerous studies have therefore focused on the pathogenesis and interventions of ORN early stage. The present study aimed to investigate whether α2­macroglobulin (α2M) could prevent early­stage jaw osteoradionecrosis caused by radiotherapy (RT). Following local injection of α2M, a single dose of 30 Gy was delivered to rats for pathological exploration. For 28 days, the irradiated mandible and soft tissues were examined for potential changes. Furthermore, primary human bone marrow mesenchymal stem cells pretreated with α2M followed by 8 Gy irradiation (IR) were also used. Tartrate­resistant acid phosphatase assay, terminal uridine deoxynucleotidyl nick end labeling assay and immunohistochemical staining were performed on irradiated mandibular bone, tongue or buccal mucosa tissues from rats. Cell proliferation was assessed by evaluating the cell morphology by microscopy and by using the cell counting kit­8. Fluorescence staining, flow cytometry and western blotting were conducted to detect the reactive oxygen species level, cell apoptosis and protein expression of superoxide dismutase 2 (SOD2), heme oxygenase­1 (HO­1) and phosphorylated Akt following irradiation. The results demonstrated that α2M attenuated physical inflammation, osteoclasts number and fat vacuole accumulation in mandibular bone marrow and bone marrow cell apoptosis following IR in vivo. Furthermore, α2M pretreatment suppressed the expression of 8­hydroxy­2'­deoxyguanosine in mandibular bone and tongue paraffin embedded sections, which is a marker of oxidative damage, and increased SOD2 expression in mucosa and tongue paraffin embedded sections. The present study demonstrated the efficient regulation of antioxidative enzymes, including SOD2 and heme oxygenase­1, and reduction in oxidative damage by α2M. In addition, in vitro results confirmed that α2M may protect cells from apoptosis and suppress reactive oxygen species accumulation. Overall, the present study demonstrated that α2M treatment may exert some radioprotective effects in early­stage ORN via antioxidant mechanisms, and may therefore be considered as a potential alternative molecule in clinical prophylactic treatments.

Protective effects of α­2­macroglobulin on human bone marrow mesenchymal stem cells in radiation injury.

Osteoradionecrosis of the jaws (ORNJ) is a complication of oral and maxillofacial malignancy that arises following radiotherapy; progressive jaw necrosis severely decreases the quality of life of patients. Human bone marrow mesenchymal stem cells (hBMMSCs) are a cell type with self­renewal and pluripotent differentiation potential in the bone marrow stroma. These cells are associated with bone tissue regeneration and are one of the primary cell types affected by bone tissue radiation injury. α­2­macroglobulin (α2M) is a glycoprotein­rich macromolecule that interacts with cytokines, growth factors and hormones to serve a variety of biological roles. In addition, α2M possesses radio­protective effects. The aim of the present study was to investigate whether α2M has protective effects against radiation injury of hBMMSCs. Cell counting kit­8 and colony formation assays were used to monitor cell proliferation. Western blot analysis and reverse transcription­quantitative polymerase chain reaction were used to detect Beclin1, microtubule­associated protein 1A/1B, sex determining region Y, Nanog, runt­related transcription factor 2, osteoglycin and manganese superoxide dismutase expression. The formation of calcium nodules was evaluated by Alizarin red staining after osteogenic induction. Flow cytometric analysis of Annexin­V and propidium iodide double staining was used to detect changes in apoptosis rate. Alkaline phosphatase and superoxide dismutase activity were determined using colorimetric assays. Reactive oxygen species levels were detected using 2',7'­dichlorodihydrofluorescein diacetate. The results of the present study revealed that α2M increased the rate of proliferation, reduced autophagy, alleviated pluripotent differentiation injury, increased the osteogenic differentiation ability and decreased the rate of apoptosis in hBMMSCs following irradiation via an antioxidative pathway. In conclusion, α2M exhibited protective effects against radiation injury in hBMMSCs and may be considered a potential therapeutic agent for the prevention and treatment of ORNJ.