Thermal responses of face-masked pedestrians during summer: An outdoor investigation under tree-shaded areas.

During the SARS-CoV-2 (COVID-19) pandemic, most citizens were cooperative towards the face-masking policy; however, undeniably, face masking has increased complaints of thermal discomfort to varying degrees and resulted in potential health hazards during summer. Thus, a thermal comfort survey was conducted under tree-shaded areas generally preferred by pedestrians to explore the thermal response of face-masked pedestrians. Thirty-two subjects, with and without masks, participated in walking experiments, and their thermal parameters and physiological indicators were recorded; moreover, the subjects were asked to fill in subjective questionnaires. The results showed that although tree shades significantly reduced the average radiant temperature, dampness in the mask may cause some discomfort symptoms, among which intense sweating (54.55%) and tachycardia (42.18%) accounted for the largest proportion. Based on thermal indices, it could be concluded that face-masking does not significantly affect the thermal comfort of subjects walking in shaded areas. Notably, a 30-min walk in tree-shaded areas with face masking does not adversely affect human health or quality of life. Thus, the present assessment of the thermal safety of humans in shaded environments provides reference data for determining thermal comfort levels during outdoor walking with face masking.

Graphene/hydroxyapatite coating deposit on titanium alloys for implant application.

Titanium (Ti) implants are widely used in medicine. Meanwhile, surface modification of Ti can strengthen the osseointegration of implants. In this study, we modified Ti implant surfaces, which was coated with GO, HA, HA-2wt%GO and HA-5wt%GO via electrophoresis deposition, to investigate their mechanisms and biological activity. Uncoated Ti was used as the control. Further, we examined the biological behavior and osteogenic performance of mouse bone marrow mesenchymal stem cells (BMSCs) cultured on coatings in vitro. We found that the HA-GO nanocomposite coating improved the roughness and hydrophilicity of the Ti surface. Compared with the uncoated Ti or Ti modified by HA or GO alone, cell adhesion and diffusion were enhanced on HA-GO-modified Ti surfaces. In addition, the proliferation and osteogenic differentiation of BMSCs in vitro were significantly improved on HA-GO-modified surfaces, whereas osteogenesis-related gene expression and alkaline phosphatase activity were slightly enhanced. Furthermore, we noted that bone regeneration was improved in the HA-2wt%GO group in vivo. Thus, the HA-2wt%GO nanocomposite coating might have potential applications in the field of dental implants.

A 3-Year Clinical Evaluation of Endodontically Treated Posterior Teeth Restored with Resin Nanoceramic Computer-Aided Design/Computer-Aided Manufacture (CAD/CAM)-Fabricated Partial Crowns.

BACKGROUND We aimed to investigate the clinical effects of resin nanoceramic (RNC) computer-aided design/computer-aided manufacture (CAD/CAM) partial crowns on posterior teeth after root canal treatment over a 3-year period. MATERIAL AND METHODS A total of 132 posterior teeth restored with CAD/CAM partial crowns were placed in 128 patients. The observation group (n=66) was restored with RNC restorations, while the control group received lithium disilicate-based glass ceramic (LDGC) CAD restorations. Using Federation dentaire internationale (FDI) World Dental Federation clinical criteria, 2 calibrated evaluators examined the performance of the restorations at baseline, 6, 12, 18, 24, and 36 months. The Kaplan-Meier method and the log-rank test were adopted to analyze the survival rate. The influence of potential risk factors on the main pattern of failure was studied by univariate Cox regression analysis (alpha=0.05). RESULTS At the 3-year followup, the survival rate of the partial crowns was 83.1% in the RNC group, and 93.5% in the LDGC group (P=0.061). Failures were caused by debonding (66.7%), restoration fracture (26.6%), and tooth fracture (6.7%). No significant differences were found between the 2 materials at 36 months, except for the parameters of "surface luster" (P=0.002) and "occlusal contour and wear" (P=0.009). The RNC group was significantly more likely to debond than the LDGC group (hazard ratio=9.22 [1.17,72.74], P=0.01). CONCLUSIONS RNC CAD/CAM-fabricated partial crowns are a potential clinical alternative for endodontically treated posterior teeth, with a survival rate of 83.1% at the 3-year followup. The main pattern of failure was debonding, which might be influenced by surface pretreatment of the RNC material.

Borderline Developmental Dysplasia of the Hip: A Risk Factor Predicting the Development and Poor Prognosis after Core Decompression for Idiopathic Osteonecrosis of the Femoral Head.

OBJECTIVE: It is unclear whether idiopathic osteonecrosis of the femoral head (ONFH) is associated with borderline developmental dysplasia of the hip (BDDH). This study aimed to compare the incidence of BDDH between patients with idiopathic ONFH and matched control subjects and determine the influence of BDDH on poor prognosis after core decompression (CD). METHODS: We retrospectively examined 78 consecutive patients (111 hips) with idiopathic ONFH undergoing CD and 1:2 matched with 156 control subjects (222 hips). The anteroposterior pelvic radiographs were used to measure the acetabular anatomical parameters and divide included subjects into BDDH or non-BDDH group. The incidence of BDDH and acetabular anatomical parameters were compared between patients with idiopathic ONFH and matched controls. Clinical outcomes, such as Harris Hip Score (HHS), progression of collapse, and conversion to total hip arthroplasty (THA), were compared between patients with BDDH and without BDDH in the idiopathic ONFH group, with a mean follow-up of 72.1 ± 36.6 months. RESULTS: Patients with idiopathic ONFH had a significantly higher incidence of BDDH than matched controls (29.7% vs 12.2%, p < 0.001). Less acetabular coverage was also found in patients with idiopathic ONFH than in matched controls as demonstrated by lower CEA (28.5° ± 4.7° vs 33.1° ± 5.7°, p < 0.001), AHI (82.4 ± 5.0 vs 86.3 ± 5.4, p < 0.001), ADR (299.6 ± 28.4 vs 318.8 ± 31.3, p < 0.001), and a higher sharp angle (40.0° ± 3.4° vs 37.4° ± 3.7°, p < 0.001). In patients with idiopathic ONFH, the BDDH group had a significantly lower mean HHS at the last follow-up (83.5 ± 17.4 vs 91.6 ± 9.7, p = 0.015) with a different score distribution (p = 0.004), and a lower 5-year survival rate with both clinical failure (66.7%, 95% CI 52.4%-84.9% vs 83.7%, 95% CI 75.2%-93.1%; p = 0.028) and conversion to THA (74.6%, 95% CI 60.7%-91.6% vs 92.1%, 95% CI 85.6%-99.0%; p = 0.008) as the endpoints than the non-BDDH group. CONCLUSION: The incidence of BDDH was significantly higher in patients with idiopathic ONFH than matched controls, and idiopathic ONFH patients who underwent CD with BDDH had lower mean HHS as well as 5-year survival rate than those without BDDH. Therefore, BDDH should be considered a risk factor predicting the development of idiopathic ONFH as well as poor prognosis after CD.

Comprehensive analysis of lncRNA-miRNA-mRNA networks during osteogenic differentiation of bone marrow mesenchymal stem cells.

BACKGROUND: Long non-coding RNA (lncRNA) plays crucial role in osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs), involving in regulation of competing endogenous RNA (ceRNA) mechanisms and conduction of signaling pathways. However, its mechanisms are poorly understood. This study aimed to investigate lncRNAs, miRNAs and mRNAs expression profiles in rat BMMSCs (rBMMSCs) osteogenic differentiation, screen the potential key lncRNA-miRNA-mRNA networks, explore the putative functions and identify the key molecules, as the basis of studying potential mechanism of rBMMSCs osteogenic differentiation driven by lncRNA, providing molecular targets for the management of bone defect. METHODS: High-throughput RNA sequencing (RNA-seq) was used to determine lncRNAs, miRNAs, and mRNAs expression profiles at 14-day rBMMSCs osteogenesis. The pivotal lncRNA-miRNA and miRNA-mRNA networks were predicted from sequencing data and bioinformatic analysis, and the results were exported by Cytoscape 3.9.0 software. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were used for functional exploration. Real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was performed to validate lncRNAs, miRNAs and mRNAs. RESULTS: rBMMSCs were identified, and the osteogenic and adipogenic differentiation ability were detected. A total of 8634 lncRNAs were detected by RNA-seq, and 1524 differential expressed lncRNAs, of which 812 up-regulated and 712 down-regulated in osteo-inductive groups compared with control groups. 30 up-regulated and 61 down-regulated miRNAs, 91 miRNAs were differentially expressed in total. 2453 differentially expressed mRNAs including 1272 up-expressed and 1181 down-expressed were detected. 10 up-regulated lncRNAs were chosen to predict 21 down-regulated miRNAs and 650 up-regulated mRNAs. 49 lncRNA-miRNA and 1515 miRNA-mRNA interactive networks were constructed. GO analysis showed the most important enrichment in cell component and molecular function were "cytoplasm" and "protein binding", respectively. Biological process related to osteogenic differentiation such as "cell proliferation", "wound healing", "cell migration", "osteoblast differentiation", "extracellular matrix organization" and "response to hypoxia" were enriched. KEGG analysis showed differentially expressed genes were mainly enriched in "PI3K-Akt signaling pathway", "Signaling pathway regulating pluripotency of stem cells", "cGMP-PKG signaling pathway", "Axon guidance" and "Calcium signaling pathway". qRT-PCR verified that lncRNA Tug1, lncRNA AABR07011996.1, rno-miR-93-5p, rno-miR-322-5p, Sgk1 and Fzd4 were consistent with the sequencing results, and 4 lncRNA-miRNA-mRNA networks based on validations were constructed, and enrichment pathways were closely related to "PI3K-Akt signaling pathway", "Signaling pathway regulating pluripotency of stem cells" and "Wnt signaling pathway". CONCLUSIONS: lncRNAs, miRNAs and mRNAs expression profiles provide clues for future studies on their roles for BMMSCs osteogenic differentiation. Furthermore, lncRNA-miRNA-mRNA networks give more information on potential new mechanisms and targets for management on bone defect.

Differential circRNA and mRNA Expression Profiling During Osteogenic Differentiation in Rat Bone Marrow Mesenchymal Stem Cells.

BACKGROUND Circular RNAs (circRNAs) play important roles in gene expression and signaling pathways. The study aimed to identify the differential expression of circRNAs and mRNAs in the osteogenic differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) and to explore the biological function of circRNAs in the osteogenic differentiation of rBMSCs. MATERIAL AND METHODS High-throughput sequencing was used to detect differentially expressed circular RNA and mRNA during osteogenic differentiation of rBMSCs. The RNAs were analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment to predict their potential role in regulating rBMSC osteogenesis. MiRanda, Circatlas, and miRDB databases were used to predict target relationships between circRNA, miRNA, and mRNA.The regulatory network was constructed by Cytoscape (version 3.6.1). The RNA-Seq findings were validated by quantitative real-time PCR (qRT-PCR). RESULTS The results revealed that 29 differentially expressed circRNAs and 2453 differentially expressed mRNAs were detected during the osteogenic differentiation of rBMSCs. Many differentially expressed circRNAs were closely related to osteogenic differentiation of cells. Among them, circRNAs_1809 and Kitlg were the significantly increased circRNA and mRNA during osteogenic differentiation of rBMSCs. The ceRNA network showed that circRNA_1809 could target the Kitlg gene through miR-370-3p. CONCLUSIONS CircRNAs may play an important role in the osteogenic differentiation of rBMSCs. CircRNA_1809 may acts as a sponge for miR-370-3p and regulate the osteogenic differentiation of rBMSCs by targeting Kitlg; however, this hypothesis needs further verification. This study laid a theoretical foundation for further understanding the mechanism of circRNAs regulating osteogenic differentiation of rBMSCs.

The management of bone defect using long non-coding RNA as a potential biomarker for regulating the osteogenic differentiation process.

Tissue engineered bone brings hope to the treatment of bone defects, and the osteogenic differentiation of stem cells is the key link. Inducing osteogenic differentiation of stem cells may be a potential approach to promote bone regeneration. In recent years, lncRNA has been studied in the field increasingly, which is believed can regulate cell cycle, proliferation, metastasis, differentiation and immunity, participating in a variety of physiology and pathology processes. At present, it has been confirmed that certain lncRNAs regulate the osteogenesis of stem cells and take part in mediating signaling pathways including Wnt/ß-catenin, MAPK, TGF-ß/BMP, and Notch pathways. Here, we provided an overview of lncRNA, reviewed its researches in the osteogenic differentiation of stem cells, emphasized the importance of lncRNA in bone regeneration, and focused on the roles of lncRNA in signaling pathways, in order to make adequate preparations for applying lncRNA to bone tissue Engineering, letting it regulate the osteogenic differentiation of stem cells for bone regeneration.

Superaerophobic copper-based nanowires array for efficient nitrogen reduction.

Electrocatalytic N2 reduction reaction (NRR) provides a promising route for NH3 production under ambient conditions to replace traditional Haber-Bosch process. For this purpose, efficient NRR electrocatalysts with high NH3 yield rate and high Faradaic efficiency (FE) are required. Cu-based materials have been recognized catalytic active for some multi-electron-involved reduction reactions and usually exhibit inferior catalytic activities for hydrogen evolution reaction. We report here the preparation and characterization of a series of Cu-based nanowires array (NA) catalysts in situ grown on Cu foam (CF) substrate, including Cu(OH)2 NA/CF, Cu3N NA/CF, Cu3P NA/CF, CuO NA/CF and Cu NA/CF, which are directly used as self-supported catalytic electrodes for NRR. The electrochemical results show that CuO NA/CF achieves a highest NH3 yield rate of 1.84 × 10-9 mol s-1 cm-2, whereas Cu NA/CF possesses a highest FE of 18.2% for NH3 production at -0.1 V versus reversible hydrogen electrode in 0.1 M Na2SO4. Such catalytic performances are superior to most of recently reported metal-based NRR electrocatalysts. The contact angle measurements and the simulated calculations are carried out to reveal the important role of the superaerophobic NA surface structure for efficient NRR electrocatalysis.

CircularRNA CDR1as promotes osteogenic differentiation and angiogenesis related genes expression in mouse bone marrow mesenchymal stem cells / 口腔疾病防治

Objective@# To investigate the effects of over expression and low expression of antisense transcripts of circular RNA cerebellar degeneration associated protein 1 (CDR1as) in Balb/C mouse bone marrow mesenchymal stem cells (BMSCs) on factors related to osteogenesis and angiogenesis.@*Methods@#BMSCs were cultured and identified in vitro. The lentiviral (LV) vector containing the overexpressed and silenced circRNA CDR1as genes and the control lentivirus were respectively transfected into mouse BMSCs, and stable cell lines were screened. The cells were divided into the circRNACDR1as over expression group and the over expression control group, and the CircRNACDR1as low expression group and the low expression control group. The components were stained with Alizarin Red S and alkaline phosphatase after 14 and 21 days of osteoinduction; qRT-PCR was used to detect the target genes circRNA CDR1as, osteogenic differentiation markers alkaline phosphatase (ALP), runt- related transcription factor 2 (RUNX2), osteocalcin (OCN), osteopontin (OPN), osterix(Osx), collagen I (COL-1), and the mRNA expression levels of vascular endothelial grown factor (VEGF) and angiogenin-1 (Ang-1). @*Results@# The results of alizarin red staining and alkaline phosphatase staining showed that the extracellular matrix calcium precipitation and ALP staining area of the over expression experimental group was greater than its control group, and those of the low expression experimental group was less than its control group. As the number of days of osteogenic induction increased, the calcium precipitation and ALP staining in each group also increased. RT-PCR results showed that the mRNA expression levels of circRNA CDR1as, ALP, RUNX2, OCN, OPN, OSX, COL-1, VEGF and Ang-1 in the over expression experimental group BMSCs were significantly increased (P<0.001). In the low expression experimental group, the mRNA expression levels of circRNA CDR1as, ALP, RUNX2, OCN, OPN, OSX, COL-1, VEGF and Ang-1 in BMSCs were significantly reduced (P<0.001). @*Conclusion@# Over expression of the circRNA CDR1as gene promotes the osteogenic differentiation and angiogenesis of BMSCs. Low expression of the circRNA CDR1as gene inhibits the osteogenic differentiation and angiogenesis of BMSCs.

Permanent Maxillary Odontometrics for Sex Estimation Based on a 3-Dimensional Digital Method.

BACKGROUND In the field of forensic medicine, sex estimation is a critical step in personal identification. Teeth are the hardest tissue and have high temperature resistance and corrosion resistance. In cases such as an airplane crash or the corpse of an unknown person, teeth often play a crucial role in identification. This study applied 3-dimensional technology to obtain odontometrics of permanent maxillary teeth and to examine the sexual dimorphism, finding suitable discriminant indicators to construct appropriate equations for sex estimation. MATERIAL AND METHODS A total of 204 participants (104 men and 100 women) from the Han population in Kashgar were included. Plaster models of their maxillary dentition were obtained to scan and measure through an accepted and commonly used 3-dimensional digital method. Descriptive statistics, t tests, and discriminant analyses were statistically analyzed using IBM SPSS 23.0 software. RESULTS This study showed high intra- and interexaminer reliability (intraclass correlation coefficient >0.950). There were statistically significant sex-related differences (P<0.05), with male values generally being higher for buccolingual distance, mesiodistal distance, intercanine distance, crown area, crown module, crown index, and maxillary canine index. Compared with other measurements, mesiodistal distance and crown area indicator exhibited distinct sexual dimorphism. In addition, several appropriate equations were constructed through different discriminant analyses that could be used to estimate sex in our specific population. CONCLUSIONS Three-dimensional digital technology offers a promising method for odontometry. Combining mesiodistal distance and buccolingual distance of particular teeth or using maxillary canine index in discriminant functions are acceptable auxiliary tools for sex estimation in the forensic field.

Efficient ∼4 µm emission from Pr3+/Yb3+ co-doped fluoroindate glass.

Pr3+/Yb3+ co-doped fluoroindate (InF3) glasses were prepared by using a traditional melt-quenching method in dry N2 atmosphere. Pumped by a 976 or 1570 nm laser diode, efficient emissions at ∼4µm were obtained from the Pr3+/Yb3+ co-doped glasses, which could be ascribed to the transition 3F4→3H6 of Pr3+ ions. The relative stimulated emission cross section was calculated to be ∼1.44×10-24m2 at 4 µm, which was ∼4.2 times larger than that of transition Ho3+:5I5→5I6 (3.4×10-25m2). In addition, combined with transitions 1G4→3F3 and 1G4→3F4 of Pr3+ ions, ultra-broadband emission ranging from 2.7 to 4.2 µm was also obtained. Our results indicate that Pr3+/Yb3+:InF3 glasses could be used to develop efficient ∼4µm lasers and widely tunable mid-infrared lasers.

Low-Cost and Convenient Microchannel Resistance Biosensing Platform by Directly Translating Biorecognition into a Current Signal.

We report a low-cost and convenient microchannel resistance (MCR) biosensing platform that uses current signal to report biorecognition. The biorecognition behavior between targets and biometric molecules (antigens, antibodies, or oligonucleotides) immobilized on magnetic beads and polystyrene (PS) microspheres induces a quantitative change in the unreacted PS microspheres. After magnetic separation, the unreacted PS microsphere solution is passed through the microchannel, leading to an obvious blocking effect, resulting in an increase in resistance, which can in turn be measured by monitoring the electric current. Thus, the biorecognition is directly converted into a detectable current signal without any bulky instruments or additional chemical reactions. The MCR biosensing platform is cost-effective and user-friendly with high accuracy. It can be an appropriate analysis technique for point-of-care testing in resource-poor settings.

Quantitative control of noise in mammalian gene expression by dynamic histone regulation.

Fluctuation ('noise') in gene expression is critical for mammalian cellular processes. Numerous mechanisms contribute to its origins, yet the mechanisms behind large fluctuations that are induced by single transcriptional activators remain elusive. Here, we probed putative mechanisms by studying the dynamic regulation of transcriptional activator binding, histone regulator inhibitors, chromatin accessibility, and levels of mRNAs and proteins in single cells. Using a light-induced expression system, we showed that the transcriptional activator could form an interplay with dual functional co-activator/histone acetyltransferases CBP/p300. This interplay resulted in substantial heterogeneity in H3K27ac, chromatin accessibility, and transcription. Simultaneous attenuation of CBP/p300 and HDAC4/5 reduced heterogeneity in the expression of endogenous genes, suggesting that this mechanism is universal. We further found that the noise was reduced by pulse-wide modulation of transcriptional activator binding possibly as a result of alternating the epigenetic states. Our findings suggest a mechanism for the modulation of noise in synthetic and endogenous gene expression systems.

Food Safety in Post-COVID-19 Pandemic: Challenges and Countermeasures.

Understanding food safety hazard risks is essential to avoid potential negative heath impacts in the food supply chain in a post-COVID-19 pandemic era. Development of strategies for virus direction in foods plays an important role in food safety and verification. Early warning, tracing, and detection should be implemented as an integrated system in order to mitigate thecoronavirus disease 2019 (COVID-19) outbreak, in which the detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is critical as it not only concerns screening of populations but also monitoring of possible contaminated sources such as the food supply chain. In this review, we point out the consequences in different aspects of our daily life in the post-COVID-19 pandemic from the perspective of the food supply chain and the food industry. We summarize the possible transmission routes of COVID-19 in the food supply chain before exploring the development of corresponding detection tools of SARS-CoV-2. Accordingly, we compare different detection methods for the virus in foods, including different pretreatments of food matrices in the virus detection. Finally, the future perspectives are proposed.

Intense emission at ∼3.3 µm from Er3+-doped fluoroindate glass fiber.

Fluoroindate glass fibers with an Er3+ doping concentration of ∼0.5mol% were fabricated by using a rod-in-tube method. Pumped by a 976 nm laser diode, intense emission at ∼3.3µm was obtained from a 40 cm long Er3+-doped fiber, which could be attributed to the transition 4S3/2→4F9/2 of Er3+ ions. The calculated emission cross section at ∼3.3µm was ∼3×10-26m2, which was ∼1.5 times larger than that of transitions Er3+:4F9/2→4I9/2 and Dy3+:6H13/2→6H15/2. In addition, broad emissions ranging from 3.1 µm to 3.85 µm were obtained in the Er3+-doped fiber under a 976 nm/1973 nm dual-wavelength pumping scheme. Our results indicated that Er3+-doped fluoroindate glass fibers had the potential for constructing efficient ∼3.3µm fiber lasers.

Dental measurements based on a three-dimensional digital technique: A comparative study on reliability and validity.

OBJECTIVE: In orthodontics and prosthodontics fields, it is often necessary to measure the crown dimensions of patient's teeth for further diagnosis and treatment. This study aims to assess the reliability and validity of dental measurements by comparing three-dimensional (3D) measurement of digital model derived from 3D handheld scanner with electronic digital caliper measurement of plaster model, providing a promising technology for dentistry. DESIGN: The mesiodistal diameter, buccolingual diameter and clinical crown height of 2800 teeth were measured on 100 sets of maxillary and mandibular dental plaster models as well as on the corresponding 3D digital models obtained by structured light scanning of the plaster models. Each measurement was performed twice by qualified operators and averaged. Twenty sets of maxillary and mandibular dentition models were randomly selected for intra and inter observer errors. The reliability was evaluated by intraclass correlation coefficient (ICC). Bland-Altman analysis was utilized to evaluate the validity of methods. RESULTS: Excellent reliability (ICC > 0.75) of intra and inter observer on traditional and digital methods were exhibited. Bland-Altman analysis showed the largest difference was the mesiodistal diameter (170/2800), and the smallest (130/2800) was the clinical crown height. Compared with other teeth, buccolingual diameter of incisors and molars, mesiodistal diameter and clinical crown height of premolars and molars displayed relative differences. The mean biases were close to zero, upper and lower 95 % limits of agreement were within 0.5 mm. CONCLUSIONS: Linear measurements obtained from 3D technique are consistent with the conventional method. The 3D technology can be clinically accepted and suitable for dental metrology.

Bacteriostatic effects of nanometer silver disinfectant on the biofilms in dental unit water lines.

BACKGROUND/PURPOSE: Dental unit water lines (DUWLs) may be contaminated by aerobic bacteria in clinical settings and comprehensive disinfecting methods should be considered without delay. Herein, this study aims to investigate the timeliness and dynamic bacteriostatic effects of different forms of nanometer silver (NMS) disinfectant on bio-film in DUWLs. MATERIALS AND METHODS: Bacterial DUWLs samples were respectively treated with different NMS forms, including liquid phase and solid phase at the concentrations of 0.25%, 0.5%, 1% and 2% and their bacteriostatic effects were observed at the 1st, 4th, 7th, 14th, 28th day. RESULTS: The bacteriostatic effects of liquid phase NMS at all concentrations were unsatisfactory and the bacteriostatic rate was only 20% at the 1st day. However, there appeared massive bacteria growth at the 4th, 7th, 14th, 28th day. Comparatively, no bacteria growth was found at the 1st, 4th, 7th, 14th, 28th day after sterilizing with different concentrations of solid phase NMS and the bacteriostatic rate was 100%. CONCLUSION: Microbial contamination in DUWLs can be disinfected by different NMS forms, among which solid phase NMS is more bactericidal against bacteria bio-films, demonstrating significant roles of solid phase NMS in preventing DUWL contamination.

Effects of hypoxia inducible factor-1α on osteogenic differentiation and angiogenesis related factors of bone marrow mesenchymal stem cells / 口腔疾病防治

Objective@#To investigate the level of hypoxia inducible factor-1α (HIF-1α) on osteoblasts and angiogenesis-associated cytokines in bone marrow mesenchymal stem cells (BMSCs) from SD rats.@*Methods@#BMSCs were isolated and cultured and identified by flow cytometry. Plasmid vectors containing upregulated and downregulated HIF-1α gene and a control vector were constructed. The plasmids were transfected into BMSCs by Lipofectamine®LTX transfection reagent, and the cells were divided into an overexpression experimental group, an overexpression control group, a low expression experimental group and a low expression control group. All components were stained with a lizarin red 3 d and 7 d after osteogenesis induction. The mRNA expression levels of the target gene HIF-1α, osteogenic differentiation-specific markers, including Runt-related transcription factor 2 (Runx2) and angiogenic markers, including platelet-derived growth factor-BB (PDGF-BB) and transforming growth factor-β (TGF-β), were detected by RT-PCR. Western blot was used to detect the protein expression of the target proteins HIF-1α, Runx2, and PDGF-BB.@*Results@# The CD29- and CD45-positivity rates of BMSC surface markers identified by flow cytometry were 98.2% and 4.2%, respectively. RT-PCR results showed that the mRNA expression of HIF-1α, Runx2, TGF-β and PDGF-BB was observably increased (P < 0.001). The mRNA expression levels of HIF-1α, Runx2, TGF-β and PDGF-BB in BMSCs from the low expression experimental group were significantly reduced (P < 0.001). Western blot results showed that the expression levels of HIF-1α, Runx2 and PDGF-BB in BMSCs from the overexpression experimental group were all increased (P < 0.001). The expression levels of HIF-1α, Runx2 and PDGF-BB in BMSCs from the low expression experimental group were reduced (P < 0.001). Alizarin red staining results showed that the area of calcium nodules in the low expression experimental group was smaller than that in low expression control group, the area of red calcium nodules in the over expression experimental group was larger than that in over expression control group, and with the increase of osteogenic induction time, the calcification area of each group also increased.@*Conclusion@# Upregulation and downregulation of HIF-1α can regulate the osteogenic differentiation and the expression of angiogenesis related factors of BMSCs.

Effect of cell sheet combined with 3D printing an antler powder/silk fibroin/polyvinyl alcohol scaffold on the repair of mandibular defects in sheep / 口腔疾病防治

Objective @#To explore the feasibility of antler powder/silk fibroin/polyvinyl alcohol scaffolds as tissue engineering bone scaffolds and the relationship between their degradation performance and the healing speed of bone defects.@*Methods @# Antler powder/silk fibroin/polyvinyl alcohol scaffolds and nano hydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds were prepared by 3D printing. The whole bone marrow culture method was used to prepare blood cell sheets of Altay big tail sheep’s iliac bone marrow. With observation times of 1, 2 and 3 months, the mandibular defects of 4 sheep were established. The experimental group was coated with antler powder/silk fibroin/polyvinyl alcohol scaffolds. The control group was coated with nanohydroxyapatite/silk fibroin/polyvinyl alcohol scaffolds. The negative control group was coated with gel-free sponges. According to the self-control method of the bilateral mandible defect area, scaffolds wrapped with cell membranes or gel sponges wrapped with cell membranes were implanted. At the ends of the first, second and third months after implantation, the experimental animals were killed, cone beam CT was performed, and paraffin sections were taken for HE staining to evaluate the effect of different scaffold materials on bone regeneration and scaffold degradation.@* Results@# Scanning electron microscopy showed that both groups had regular pores and good continuity, and there was no difference in pore size and porosity between the two groups (P > 0.05). The results of CBCT imaging showed that in 3 months after operation, the experimental group had significantly better repair effects on bone defects than the control group, and the degradation rate matched the bone repair rate. The bone mineral density in the center of the defect was higher than that of the control group, which was close to that of normal bone tissue. The central bone mineral density of the experimental group at each time point was higher than those of the control group and the negative control group, and the difference was statistically significant (P < 0.05). HE staining results showed that the bone cells in the experimental group were more active, with more new capillaries and bone trabeculae formed, and the scaffold material absorbed more than the control group. @*Conclusion @#The antler powder/silk fibroin/polyvinyl alcohol scaffold can promote the repair of critical bone defects. Its degradability matches its bone tissue healing rate. It is expected to become a promising scaffold material for bone tissue engineering.

Ultrasensitive determination of organotin compounds in plastic food packaging and edible oils by sheathless capillary electrophoresis-electrospray ionization-mass spectrometry.

The determination of trace-amount organotins in plastic food packaging materials is of great significance in food safety. However, due to the complexity of organotins and sample treatment processes, it is still a challenging task. Here, we report a method for the sensitive and simultaneous determination of organotins in plastic food packaging materials and edible oils, by utilizing sheathless capillary electrophoresis-electrospray ionization-mass spectrometry. The method of sample pretreatment with ultrasonic extraction and solid phase extraction is used to eliminate interference. The results showed low limits of detection (LODs) of 2 pg mL-1-50 pg mL-1 and excellent inter/intra-day repeatability. Good average recoveries in the range of 80.27% to 108.52% were obtained at three spiked concentrations, with a relative standard deviation less than 8.71%. The successful simultaneous determination of the target analytes will pave the way for further assessment of contamination and migration behaviour of organotins from packaging materials to food, which is of great significance for evaluating and controlling food safety.