Surface Structure Engineering of PdAg Alloys with Boosted CO2 Electrochemical Reduction Performance.

Converting carbon dioxide into high-value-added formic acid as a basic raw material for the chemical industry via an electrochemical process under ambient conditions not only alleviates greenhouse gas effects but also contributes to effective carbon cycles. Unfortunately, the most commonly used Pd-based catalysts can be easily poisoned by the in situ formed minor byproduct CO during the carbon dioxide reduction reaction (CRR) process. Herein, we report a facile method to synthesize highly uniformed PdAg alloys with tunable morphologies and electrocatalytic performance via a simple liquid synthesis approach. By tuning the molar ratio of the Ag+ and Pd2+ precursors, the morphologies, composition, and electrocatalytic activities of the obtained materials were well-regulated, which was characterized by TEM, XPS, XRD, as well as electrocatalytic measurements. The CRR results showed that the as-obtained Pd3Ag exhibited the highest performance among the five samples, with a faradic efficient (FE) of 96% for formic acid at -0.2 V (vs. reference hydrogen electrode (RHE)) and superior stability without current density decrease. The enhanced ability to adsorb and activate CO2 molecules, higher resistance to CO, and a faster electronic transfer speed resulting from the alloyed PdAg nanostructure worked together to make great contributions to the improvement of the CRR performance. These findings may provide a new feasible route toward the rational design and synthesis of alloy catalysts with high stability and selectivity for clean energy storage and conversion in the future.

METTL3-mediated m6A modification regulates cell cycle progression of dental pulp stem cells.

BACKGROUND: Dental pulp stem cells (DPSCs) are a promising cell source in endodontic regeneration and tissue engineering with limited self-renewal and pluripotency capacity. N6-methyladenosine (m6A) is the most prevalent, reversible internal modification in RNAs associated with stem cell fate determination. In this study, we aim to explore the biological effect of m6A methylation in DPSCs. METHODS: m6A immunoprecipitation with deep sequencing (m6A RIP-seq) demonstrated the features of m6A modifications in DPSC transcriptome. Lentiviral vectors were constructed to knockdown or overexpress methyltransferase like 3 (METTL3). Cell morphology, viability, senescence, and apoptosis were analyzed by ß-galactosidase, TUNEL staining, and flow cytometry. Bioinformatic analysis combing m6A RIP and shMETTL3 RNA-seq functionally enriched overlapped genes and screened target of METTL3. Cell cycle distributions were assayed by flow cytometry, and m6A RIP-qPCR was used to confirm METTL3-mediated m6A methylation. RESULTS: Here, m6A peak distribution, binding area, and motif in DPSCs were first revealed by m6A RIP-seq. We also found a relatively high expression level of METTL3 in immature DPSCs with superior regenerative potential and METTL3 knockdown induced cell apoptosis and senescence. A conjoint analysis of m6A RIP and RNA sequencing showed METTL3 depletion associated with cell cycle, mitosis, and alteration of METTL3 resulted in cell cycle arrest. Furthermore, the protein interaction network of differentially expressed genes identified Polo-like kinase 1 (PLK1), a critical cycle modulator, as the target of METTL3-mediated m6A methylation in DPSCs. CONCLUSIONS: These results revealed m6A methylated hallmarks in DPSCs and a regulatory role of METTL3 in cell cycle control. Our study shed light on therapeutic approaches in vital pulp therapy and served new insight into stem cell-based tissue engineering.

Simultaneous scattering-absorption dual-modal cell imaging in a single shot by a transmission-mode photoacoustic microscope.

A microscopy scheme is proposed to simultaneously achieve optical scattering-absorption dual-contrast imaging of a transparent or semi-transparent specimen. This scheme is based on a transmission-mode photoacoustic microscope. We find that two peaks exist in the detected photoacoustic signal. One peak is caused by the optical absorption of the specimen, and the other is related to both the optical scattering and absorption of the specimen. Therefore, both the absorption and scattering information can be simultaneously extracted by analyzing the same photoacoustic signal excited by a single-shot laser pulse. After the microscope is validated by imaging a binary mixture consisting of particles with different optical properties, it successfully acquires dual images of red blood cells with different contrasts. Quantitative analysis reveals that the optical absorption and scattering properties of the specimen can be derived from the two images. The proposed dual-modal imaging method would be useful in revealing the structural and functional properties of tissues at the cell level or the clinical assessment of pathological sections.

Cryogel biocomposite containing chitosan-gelatin/cerium-zinc doped hydroxyapatite for bone tissue engineering.

The present examination includes manufacture and portrayal of cryogel bio-composite implants containing chitosan-gelatin (CS-GT), cerium-zinc doped hydroxyapatite (CS-GT/Ce-Zn-HA) by cryogelation technique. The prepared cryogel biocomposites (CS-GT/HA and CS-GT/Ce-Zn-HA) were described by scanning electron microscope (SEM) and X-Ray diffraction (XRD) contemplates. The expansion of Ce-Zn in the CS-GT implants essentially expanded growing, diminished swelling, expanded protein sorption, and expanded bactericidal movement. The CS-GT/Ce-Zn-HA biocomposite had non-toxic towards rodent osteoblast cells. So the created CS-GT/Ce-Zn-HA biocomposite has favorable and potential applications over the CS-GT/HA platforms for bone tissue engineering.

[Analysis of clinical aesthetic effect of buccal alveolar ridge preservation and connective tissue transplantation with single implant].

PURPOSE: To evaluate the clinical aesthetic effect of buccal alveolar ridge preservation (ARP) and connective tissue transplantation (CTG) in patients who received a single implant. METHODS: Forty-three patients with tooth loss admitted to the Department of Stomatology of Shunde Hospital of Southern Medical University from May 2014 to May 2016 were included in the study. Tooth extraction, ARP, implant implantation, CTG and permanent repair were performed respectively. The incidence of bleeding, depth of probing, marginal bone resorption, and red-white aesthetic effect of implants were evaluated 1 year and 3 years after surgery. The buccal mucosa thickness of implants before, immediately after CTG, 1 year and 3 years after surgery were measured. The patient satisfaction was evaluated by visual analogue scale (VAS) from masticatory function, overall aesthetics, attachment height, and color, respectively. The implant conditions at the third year after surgery were observed, and complications during follow-up were recorded. SPSS 20.0 software package was used for statistical analysis of the data. RESULTS: The follow-up rate in the first year after surgery was 100%, and that in the third year after surgery was 90.70%. One year and 3 years after operation, the aesthetic effect of the implant was satisfactory. At the 3rd year after operation, the scores of the near middle gingival papillary were significantly higher than that at the 1st year after operation (P<0.05). The buccal mucosal thickness of the implant immediately after CTG and 1 year and 3 years after surgery increased significantly compared with that before CTG (P<0.05). The buccal mucosal thickness of the implant increased 1.02 mm (relative stability: 90.12%) 1 year after operation and 1.01 mm (relative stability: 84.31%) 3 years after operation, respectively. The satisfaction scores of the patients on chewing function, overall aesthetics, attachment height and color of the implant immediately after CTG, one year after surgery and 3 years after surgery were all > 8. The 3-year survival rate of the implants was 100%, and the 3-year success rate of the implants was 97.44%. During the follow-up, two patients developed peri-implant mucositis, which was relieved after tooth cleaning, but no complications such as tissue flap necrosis, limited opening and tongue movement disorder occurred. CONCLUSIONS: ARP and CTG have good clinical and aesthetic effects on patients with tooth loss. In three years, the buccal mucosal thickness of the implant can be increased and relatively stable, which is worthy of clinical promotion and application.

A Risk Score System for Myopia Symptom Warning.

Myopia is the leading cause of visual impairments worldwide. Some studies revealed that visual experience in early life affected the final myopia, indicating that environmental factors play an impellent role in the development of myopia. However, risk factors of myopia are still not identified among adolescents in China. A total of 4104 cases of myopia symptom and 3306 emmetropia controls were selected from students in primary and middle schools in Wuhan in 2008. We identified the risk factors associated with myopia symptom by multivariate logistic regression in this cross-sectional study and constructed a risk score system for myopia symptom. The value of the area under the receiver operating characteristic curve (ROC) was 0.735. Furthermore, we followed up 93 students aged 7-9 years for one year and calculated the total points using the score system. We found no significant difference between the final myopia symptom and the results predicted by the total points by pair chi-square test (P>0.05). The score system had a modest ability to estimate the risk factors of myopia symptom. Using this score system, we could identify the students who are at risk of myopia symptom in the future according to their behaviors and environmental factors, and take measures to slow the progress of myopia symptom.

Association between parents' attitudes and behaviors toward children's visual care and myopia risk in school-aged children.

The purpose of this survey was to determine the association of parents' attitudes and behaviors toward children's visual care with myopia risk in school-aged children.A total of 894 parents of school-aged children were investigated in primary and middle schools in the central and noncentral urban area in Wuhan through stratified cluster random sampling on July, 2015. We analyzed the association by the generalized linear mixed model.The results indicated that children with parents' high expectations of 1.5 or higher on their vision exhibited a decreased risk of myopia compared with 1.0 and 0.5 or lower (OR = 0.49, 95%CI = 0.36-0.67). Children whose parents only paid attention to their vision in junior and senior school and in primary school had an increased myopia risk than that in preschool (OR = 2.12, 95%CI = 1.01-4.45, and OR = 3.11, 95%CI = 1.28-7.58, respectively). Children whose parents ensured for their sufficient sleep had a decreased myopia risk (OR = 0.45, 95%CI = 0.24-0.85). Compared with children whose parents who never adjusted electronic devices' parameters, the odds ratio of sometimes was 0.49 (95%CI = 0.31-0.79), often 0.53 (95%CI = 0.33-0.85), and always 0.44 (95%CI = 0.26-0.75), respectively.Parents' attitudes and behaviors toward children's visual care are significantly associated with the myopia risk in school-aged children. Consequently, efforts should be made to educate parents on how they protect children's vision and reduce their risk of myopia.

Sciatic nerve regeneration using a nerve growth factor-containing fibrin glue membrane.

Our previous findings confirmed that the nerve growth factor-containing fibrin glue membrane provides a good microenvironment for peripheral nerve regeneration; however, the precise mechanism remains unclear. p75 neurotrophin receptor (p75(NTR)) plays an important role in the regulation of peripheral nerve regeneration. We hypothesized that a nerve growth factor-containing fibrin glue membrane can promote neural regeneration by up-regulating p75(NTR) expression. In this study, we used a silicon nerve conduit to bridge a 15 mm-long sciatic nerve defect and injected a mixture of nerve growth factor and fibrin glue at the anastomotic site of the nerve conduit and the sciatic nerve. Through RT-PCR and western blot analysis, nerve growth factor-containing fibrin glue membrane significantly increased p75(NTR) mRNA and protein expression in the Schwann cells at the anastomotic site, in particular at 8 weeks after injection of the nerve growth factor/fibrin glue mixture. These results indicate that nerve growth factor-containing fibrin glue membrane can promote peripheral nerve regeneration by up-regulating p75(NTR) expression in Schwann cells.

[Tyrosine kinase 2 with immunoglobulin-like and epidermal growth factor homology domains RNA interference inhibit the proliferation of human umbilical vein endothelial cells].

OBJECTIVE: The purpose of this study was to investigate the regulatory role of tyrosine kinase 2 with immunoglobulin-like and epidermal growth factor homology domains (Tie2) on apoptosis and proliferation in the endothelial cells. METHODS: RNA interference (RNAi) technique was used to silence Tie2 gene expression by transfecting an expression vector containing short hairpin RNA(shRNA) for Tie2 into human umbilical vein endothelial cells (HUVECs). Real time quantitation reverse transcriptase polymerase chain reaction (QRT-PCR) and Western blot were used to monitor Tie2 mRNA, as well as protein expression. The proliferation of HUVECs was examined by methyl thiazolyl tetrazolium (MTT), and the apoptosis was detected under microscope. HUVECs transfected with pGenesil-hk was negative control, and HUVECs transfected with nothing was empty control. RESULTS: Tie2 mRNA expression was down-regulated 24 h and 48 h after transfection, and Tie2 protein expression was significantly down-regulated at 24 h and 48 h (P< 0.05), especially 48 h after transfection. The apoptosis rate was conspicuously higher in experimental group than in negative control and empty control group after 48 h (P<0.05). The growth monitoring showed that proliferation was also markedly inhibited in experimental group (P<0.05) compared with two control groups. CONCLUSION: Down-regulated expression of Tie2 by RNAi can promotes apoptosis of HUVECs and has an anti-proliferation activity effect on them.

Suppression of murine melanoma growth by a vaccine of attenuated Salmonella carrying heat shock protein 70 and Herpes simplex virus-thymidine kinase genes.

Attenuated Salmonella can invade tumor cells and acts as a eukaryotic expression vector for gene propagation. We constructed a bi-gene, eukaryotic co-expression DNA vaccine of Mycobacterium tuberculosis heat shock protein 70 (mtHSP70) and Herpes simplex virus-thymidine kinase (HSV-tk) and used attenuated Salmonella as a vector to treat murine melanoma. In vitro, recombinant Salmonella can carry plasmid stably and can invade into the cytoplasm of B16 tumor cells expressing the protein of the mtHSP70/HSV-tk gene by Western blot assay. In vivo, after the recombinant Salmonella was injected into tumors, the HSV-tk precursor drug ganciclovir (GCV) was administered to start the HSV-tk killing of tumor cells. We found that the mtHSP70/HSV-tk recombinant bacteria can raise CD8+ T lymphocytes in peripheral blood by flow cytometry and in tumor tissues by immunofluorescence detection, increase IFN­Î³ contents in tumor tissue by ELISA and significantly suppress tumor growth.

Diaqua-bis-(3-nitro-benzoato-κO)bis-[1H-5-(3-pyrid-yl)-3-(4-pyrid-yl)-1H-1,2,4-triazole-κN]cobalt(II) dihydrate.

In the centrosymmetric title compound, [Co(C(7)H(4)NO(4))(2)(C(12)H(9)N(5))(2)(H(2)O)(2)]·2H(2)O, the Co(II) atom, located on an inversion center, is coordinated by two N atoms [Co-N = 2.155 (3) Å] and four O atoms [Co-O = 2.099 (2)-2.117 (3) Å] in a distorted octa-hedral geometry. Inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds link the components into a three-dimensional supramolecular framework.

[Construction of the eukaryotic coexpression vector containing Mycobacterium tuberculosis heat shock protein 70 and green fluorescent protein].

OBJECTIVE: To construct an eukaryotic coexpression vector containing Mycobacterium tuberculosis heat shock protein 70 (mtHSP70) and enhanced green fluorescent protein (EGFP) controlled by cytomegalovirus promoter using pIRES-EGFP vector. METHODS: The mtHSP70 gene fragment was amplified by PCR from pVAX-mtHSP70-HSV2gD using specific primers. The PCR product was cloned into the vector pMD 18-T vector, and the correct clone was selected according to DNA sequence analysis. The interested mtHSP70 gene fragment was subcloned into pCMV-IRES-EGFP vector with XhoI and EcoR I digestion. The recombinant plasmid was transfected into mouse melanoma B16 cell line, and the green fluorescent cells were detected by fluorescence microscopy and mtHSP70 expression was detected by Western blotting. RESULTS: The recombinant plasmid obtained was confirmed by enzyme digestion. The transfected mouse melanoma B16 cells exhibited green fluorescence under fluorescence microscopy and expressed mtHSP70 protein as demonstrated by Western blotting. CONCLUSION: The eukaryotic coexpression vector PCMV-mtHSP70-IRES-EGFP has been established to allow further investigation of the role of mtHSP70 gene in tumor immunotherapy.

[Culture and identify the human umbilical vein endothelial cells and investigate the expression of tyrosine kinase-2 with immunoglobulin-like and epidermal growth factor homology domains in the cells].

OBJECTIVE: To study the cultural method and identification of human umbilical vein endothelial cells (HUVECs), and investigate the expression of tyrosine kinase-2 with immunoglobulin-like and epidermal growth factor homology domains(Tie-2) in HUVECs. METHODS: HUVECs were isolated from umbilical veins by the technique of irrigative digestion, and were cultivated in plates. The cells were identified by VIII monoclonal antibody. Tie-2 mRNA and protein were detected by reverse transcription-polymerase chain reaction (RT-PCR) and SABC immunocytochemistry. RESULTS: HUVECs could adhere to the plates completely after 24 hours, and confluence a monolayer 4-5 days later. The band of Tie-2 mRNA was obviously and the expression of Tie-2 protein was strongly positive by immunocytochemistry in HUVECs. The positive rate was over 85%. CONCLUSION: Highly purified endothelial cells were isolated. And there were overexpression of Tie-2 in HUVECs.

[Effect of vascular endothelial growth factor 165 gene transfection on repair of bone defect: experiment with rabbits].

OBJECTIVE: To investigate the influence of vascular endothelial growth factor (VEGF) 165 gene transfection on the repair of bone defect. METHODS: 38 New Zealand rabbits underwent resection of a segment 1 cm in length in bilateral radii filled with absorbable gelatin sponge. Dilated solution of the plasmid pcDNA3.1/VEGF165 was injected into the bone defect of one side and normal saline was injected into the contralateral bone defect. 1, 2, 4, 6, 8, and 12 weeks later X ray examination was conducted to observe the repair of bone defect, and then 5 rabbits were killed at each time points to take out the bone defects. HE staining was used to observe the bone repair. The levels of microvessel density (MVD) 1 and 2 weeks after the operation were observed. RT-PCR was used to detect the mRNA expression of VEGF in the bone defect. Based on the results of RT-PCR the tissue mRNA expression of VEGF65 was detected by real-time quantitative polymerase chain reaction (RQ-PCR). RESULTS: X-ray examination showed that there was no significant difference in the wound healing between the two group 1 week after the operation in all rabbits. Some callus could be seen in the experimental group 2 weeks after. Twelve weeks after the operation the reconstruction of bone cortex was completed. Similar process occurred in the control sides but more lately. The MVD level 7 days after of the experimental group was 47.0 +/- 7.5, significantly higher than that of the control group (42.2 +/- 6.4, t = 2.4519, P = 0.0179), and the MVD level 14 days after of the experiment group was 69.1 +/- 5.4, significantly higher than that of the control group (56.1 +/- 6.1, t = 8.0347, P = 0.0000). In the experimental group the mRNA expression amounts of VEGF165 could be found 1 week after, gradually increased and peaked 3 weeks after, then decreased, and became stable 6 weeks after. The mRNA expression amounts of VEGF165 in the control group were lower than those of the experimental group. CONCLUSION: Local application of PcDNA3.1/VEGF(165) vector promotes the expression of VEGF165, and enhances the quantity of the angiogenesis, extra cellular matrix and healing of bone defect.

Effect of vascular endothelial growth factor 165 gene transfection on bone defects and its mRNA expression in rabbits.

BACKGROUND: Gene therapy has been a hot spot in repair of bone defects in recent years. This study aimed to construct a recombinant plasmid pcDNA3.1-VEGF(165), and to observe the effect of vascular endothelial growth factor 165 (VEGF(165)) gene therapy on bone defects in rabbits. METHODS: Total RNA was extracted from rabbit bone tissues. VEGF(165) cDNA fragment was prepared by reverse transcription and the gene was cloned by polymerase chain reaction (PCR). Plasmid pMD18-T/VEGF(165) combined with pcDNA3.1 was cloned to reconstruct pcDNA3.1-VEGF(165) plasmid. Thirty New Zealand white rabbits weighing (2.50 +/- 0.13) kg were used to establish models of bone defects (1 cm in length) of the bilateral radii. The bone defects were repaired with absorbable gelatin sponge. After the operation, physiological sodium chloride solution was injected into the injured site in one of the forelegs of the rabbits as the control group, and pcDNA3.1-VEGF(165) plasmid (0.2 ml, 200 ng) was injected into the opposite foreleg as the experiment groups. At weeks 1, 2, 4, 6, 8, and 12 after the treatments, the bones were examined by X-ray, and the specimens of the bone defects were collected, stained with HE, and observed under a light microscope. The expression of VEGF(165) mRNA was examined by real-time quantitative polymerase chain reaction (RQ-PCR). RESULTS: The pcDNA3.1-VEGF(165) plasmid with a correct sequence was constructed successfully. Postoperative X-ray found no difference between the two groups at week 1. In the experiment group, callus and synostosis were observed after 2 weeks, and osteosis structure was normal at week 12; these phenomena occurred much later in the control group. In the experiment group, HE staining showed a large amount of newly formed blood vessels after 2 weeks, a number of bone trabeculae with osteoblasts proliferation at 4 weeks, and fresh bone cortex and reformed medullary cavity at 12 weeks; whereas in the control group these structures formed in later phases. The VEGF(165) mRNA in the experiment group was expressed at a low level at week 1, reached the peak at weeks 3, and then decreased to a normal level after 6 weeks. CONCLUSIONS: Local use of pcDNA3.1-VEGF(165) plasmid at bone defects can upregulate the expression of VEGF(165) and accelerate the formation of capillaries and the repair of bone defects. Angiogenesis and osteogenesis can be promoted by a combination of pcDNA3.1-VEGF(165) and gelatin sponge.

[The effect of pcDNA3.1-vEGF165 recombined vector on wound healing and the expression of collagen type I, III mRNA in wounded tissue].

OBJECTIVE: To examine the effect of pcDNA3.1-VEGF165 vector to the angiogoiesis, expression of collagen type I and type III mRNA in soft tissue injury model. METHODS: Thirty two Sprague-Daulay rats,weighted (180 +/- 20) g, were made tissue injury in the bilateral of vertebral region. Round wound (diameter 12 mm) was made by perforex on the back, removed the skin and 2 mm muscle, one side was experimental group by random and the other as control. The wound was done with sodium chloride (0.2 ml) in the control group, with the recombinant VEGF165 vector (0.2 ml, 200 mg) in the experimental group. The wound healing and other general state of health was observed after the operation. The specimens were obtained at 3,5, 7,14 and 30 days after injury. Draw the materials from the rats at the same time, all samples were divided into two parts. one ( > 0.1 g) was conserved in refrigerator at - 80 degrees C, which was extracted total RNA by TRIZOL, design the primer of rat's collagen type I and type III, RT-PCR analysis indicated that collagen type I, III. The other was fixed by 10% formalin. Examine wound healing of local tissue and count it' s MVD by HE staining. RESULTS: All the rabbits were well alive, no death or infection. Wound healing time was shorter than the control one (14.2, 17.4 d). Inflammatory cell infiltrate, cellula intersitialis, fibroblast, collagen and the density of angiogenesis were more in the experimental group than in the control one. The MVD was significant difference between the two groups at 1, 2 weeks are 63.38 +/- 9.20, 52.72 +/- 7.06 and 76.64 +/- 12.27, 66.84 +/- 9.82 (P < 0.05). The expression of collagen type I , III mRNA was found in the third day, the peak was in the second week and then degression. The collagen type I , III mRNA and beta-actin specificitic belt were found and its initial template volume different, the results was trend of RT-PCR obtained. CONCLUSIONS: The local application of pcDNA3.1-VEGF165 can enhance the expression of collagen type I, III mRNA, enhance angiogenesis and extra cellular matrix, both of which can shorten healing time of tissue injury.