BACKGROUND:Micro-arc oxidation technique is used to modify the surface properties of titanium and titanium al oy.
OBJECTIVE:To explore the surface properties of micro-arc oxidation film and its effect on the attachment, proliferation and alkaline phosphatase activity of MC3T3-E1.
METHODS:Forty-six pure titanium discs, 10 mm in diameter and 2 mm in thickness, were randomly divided into two groups. The discs of the experimental groups were treated by micro-arc oxidation technique in an electrolytic solution containing 0.02 mol/L sodiumβ-glycerophosphate and 0.2 mol/L calcium acetate;while the discs of the control group was machine-polished. The surface appearance of the discs was observed by a scanning electron microscopy, the ratio of calcium to phosphorus on the coating surface was detected by X-ray spectroscopy, and the crystal ine phase composition of the coating was detected by X-ray diffraction analysis. cellular morphology in the process of attachment was observed under the scanning electron microscope. cellproliferation was determined by cellcounting kit-8 at 2, 4, 74 days, while alkaline phosphatase activity were determined at 7 and 14 days.
RESULTS AND CONCLUSION:After micro-arc oxidation treatment, a rough and porous calcium-phosphate film was formed on the surface of titanium. The elements of micro-arc oxidation coating main mainly included Ca, P, O and Ti, and the micro-arc oxidation film was mainly composed of titanium oxide, calcium titanate, calcium phosphate and calcium metaphosphate. Under the scanning electron microscope, pseudopods appeared to grow out of the cells on the surface of micro-arc oxidation coating after 1 hour culture, and the typical morphology of the MC3T3-E1 cells could be observed at 4 hours. MC3T3-E1 proliferation (4 and 7 days of culture) and alkaline phosphatase activity (7 and 14 days of culture) were enhanced significantly in the micro-arc oxidation group compared with the control group. These findings indicate that the rough and porous calcium-phosphate coating produced by micro-arc oxidation technique on pure titanium surface could promote the early attachment, proliferation and osteogenic differentiation of MC3T3-E1.

To explore the long-term effects of L-T4 treatment on physical and intellectual development in neonatal congenital hypothyroidism(CH) patients during adolescence and adulthood.14 out of 15 patients,aged 15-31 years old,including 9 males and 6 females,were diagnosed by neonatal screening for congenital hypothyroidism.(1) By treatment for 10 years until adolescence,return visit ages were 12.6-18.1 years old,the height of patients were normal in 14 cases,weight normal in 8 cases,and overweight in 6 cases.Only the first patient of neonatal screening for congenital hypothyroidism height 154 cm,weight of 43.5 kg,which were below the standard.Bone age by X-ray showed 9 normal,1 case of rapid development,4 cases with left wrist bone age retardation.IQ combined Raven's test(CRT) showed 3 cases excellent,7 cases normal,3 cases borderline,and 2 cases low.(2)Treatment for more than 20 years to adulthood,9 cases of return visits (8 cases were screened out) by 23-31 years of age,with 5 males and 4 females,height and bone age were all normal,normal weight,only 2 cases BMI slightly overweight.As to IQ,good were in 7 cases,mild retardation in 2 cases.7 patients received above average education;they were all employed except one.The employed patients were all capable for their jobs.In summary,screening out of 8 patients,1 case were of mild mental retardation (12.5％);while 7 patients(87.5％),both in physical and intellectual levels were as those of the normal population.

In the present study, porous PCL (poly (epsilon-caprolactone)) scaffolds were prepared through a melted extrusion manufacturing (MEM) machine, and carboxylate groups were formed on the surfaces of specimen by hydrolyzation with NaOH aqueous solutions. Apatite precursor was introduced on the surfaces of specimens with CaCl2 and K2 HPO4 under vacuum condition, and mineralization study was applied to these specimens. The results showed that the hydrophilicity of PCL surface was improved with the introduction of carboxylate groups, and the contact angle of surface was decreased to 26.52 degrees. A dense and uniform bone-like layer was confirmed to be formed on the surface of Ca-P treated specimens after mineralizing for less than 24 h in SBF by SEM and EDAX.
Biocompatible Materials ; chemistry ; Bone Regeneration ; Guided Tissue Regeneration ; methods ; Humans ; Polyesters ; chemical synthesis ; Tissue Engineering ; Tissue Scaffolds ; chemistry

OBJECTIVETo study the incorporation rate and release behavior of bovine serum albumin (BSA) incorporated into the calcium phosphate coating by biomimetic deposition, as well as the physical and chemical properties of the hybrid coating, and to provide experimental basis for the fabrication of growth factor/biomimetic calcium phosphate coating and exploration for the loading/release behavior of growth factors.

METHODSPure titanium specimens were immersed into saturated calcium phosphate solutions(SCP) containing no BSA (controlled group) and 3 different concentrations of BSA (experimental groups) : 1, 10 and 100 mg/L. Biomimetic calcium phosphate coating was formed on titanium surface and BSA was incorporated into the coating through co-deposition. The topography of the specimen was observed using scanning electron microscopy (SEM). Chemical structure and phase composition of coatings were detected by Fourier infrared spectroscopy (FTIR) analysis and X-ray diffraction (XRD) respectively. BSA incorporation rate and release profile were determined by bicinchoninic acid protein assay kit.

RESULTSThe biomimetic calcium phosphate coating was mainly composed of hydroxyapatite and octacalcium phosphate. BSA was successfully incorporated into the calcium phosphate coatings in all the 3 experimental groups. With the increase of BSA concentration, plate-like units of the coatings were turned into small grid structure. BSA incorporation rates of the three experimental groups were (72.4 ± 2.4)%, (62.3 ± 0.9)% and (42.2 ± 1.7)% respectively. The in vitro release test showed that all three BSA release profiles could be divided into two significant different stages: early burst release stage and later sustained release stage. The amount of BSA release of the 3 experimental groups in 24 h and 30 d were (1.57 ± 0.09), (8.82 ± 0.93), (140.24 ± 3.12) µg, and (2.39 ± 0.29), (14.39 ± 0.70), (151.06 ± 2.00) µg respectively.

CONCLUSIONSBiomimetic calcium phosphate coating can be used as an effective carrier for protein. BSA concentration has an impact on the incorporation rate and release speed of BSA from the calcium phosphate coating. Favorable BSA incorporation rate and release behavior can be obtained at BSA concentration of 10 mg/L.

Biomimetic Materials ; Calcium Phosphates ; chemistry ; Durapatite ; In Vitro Techniques ; Microscopy, Electron, Scanning ; Serum Albumin, Bovine ; metabolism ; Spectrophotometry, Infrared ; Surface Properties ; Titanium ; X-Ray Diffraction

OBJECTIVETo evaluate the platelet adhesion ability on pure titanium surfaces modified with different techniques.

METHODSPure titanium specimens were treated with 5 different surface modification techniques, including machine polish (MP), dual acid-etch (DAE), sand blast-large grit and acid-etch (SLA), micro-arc oxidation (MAO) and anodized titania nanotube (TNT). The surface topographies of specimens were observed by scanning electron microscopy (SEM). Chemical compositions, surface roughness and static water contact angle of specimens were detected by energy dispersive spectrometer (EDS), laser scanning confocal microscope (LSCM) and contact angle analyzer respectively. Platelets were cultured on specimen surfaces for 30 min. The amount and viability of adhered platelets adhered were evaluated. Platelet distribution and morphology were observed by LSCM and SEM.

RESULTSSurface topographies of the five groups of specimens differed significantly. MP, DAE, SLA and MAO surfaces showed micro-scale topographies, while TNT surfaces showed nano-scale topography with nanotubes at the diameter of (80.46 ± 0.35) nm. The surface roughness of MAO was the highest among the 5 groups. TNT surfaces demonstrated the lowest roughness as well as the lowest static water contact angle as 13.55° ± 0.96°. The amount of platelets adhered on TNT surface was the greatest as (300 729 ± 8 325) platelet/µl and the viability was the highest (A450 value 2.14 ± 0.05). Platelet adhered intensively on TNT surfaces, forming pseudopodia, extending and connecting with each other.

CONCLUSIONSSurface properties of pure titanium affect platelet adhesion ability. Nano-scale topography can greatly improve platelet adhesion. Increased surface roughness and hydrophilicity can improve platelet adhesion ability.

Blood Platelets ; Dental Etching ; Dental Polishing ; Humans ; Microscopy, Electron, Scanning ; Nanotubes ; Oxidation-Reduction ; Platelet Adhesiveness ; Surface Properties ; Titanium

Objective: To analyze the current status of work-related musculoskeletal disorders (WMSDs), work fatigue and musculoskeletal pain in Chinese occupational population, and to study the relationship between work fatigue and musculoskeletal pain and WMSDs. Methods: A total of 66 961 employees from 323 enterprises in 15 key industries in China were selected as the study subjects using stratified cluster sampling method. The incidence of WMSDs in the past year was investigated using the Chinese version of the Musculoskeletal Disorders Questionnaire, and the work fatigue and musculoskeletal pain were investigated using Borg 6-20 Rating of Perceived Exertion Scale and visual analogue scale. The data were standardized using the age composition data of 18 to 60 years from the seventh national population census. Results: The standardized annual incidence of WMSDs was higher in the front-line workers than that in the administrative and other supportive staff (38.82% vs 36.30%). The detection rates of work fatigue and musculoskeletal pain in the study subjects were 44.54% and 63.08%, respectively. The result of S-curve fitting showed that the risk of WMSDs increased with the level of work fatigue (P<0.01). Among the front-line workers, the average of monthly fatigue frequency in the neck, shoulder, lower back, upper back, wrist/hand, foot and ankle, knee, leg, and elbow were higher in the group with WMSDs compared to those without WMSDs (all P<0.01). The pain degree of musculoskeletal pain was higher in all nine sites in the fatigued group than in the no-fatigue group (all P<0.01). The standardized detection rate of musculoskeletal pain was higher in the fatigued group than in the non-fatigued group (80.38% vs 25.71%). The work fatigue was moderate and positively correlated with musculoskeletal pain in all seven sites except the lower back and elbow, with Kendall Tau-b correlation coefficients ranging from 0.423 to 0.546 (all P<0.01). Conclusion: There is a good correlation between work fatigue and local musculoskeletal pain, work fatigue and WMSDs in Chinese occupational population. Implementing ergonomic interventions to control the development of work fatigue can be an effective measure for preventing WMSDs.

Objective: To investigate the epidemiological and clinical characteristics of 91 cases of dengue fever outbreak in Jiangxi Province in 2019, and to strengthen the management and prevention of dengue fever. Methods: The clinical data, laboratory results and etiology tests of 91 patients with dengue fever from the Ninth Hospital of Nanchang, Zhangshu People′s Hospital, Fengcheng People′s Hospital and Nanchang County People′s Hospital from July 31, 2019 to September 27, 2019 were retrospectively collected. The t test was used for continuous variables and chi-square test was used for categorical variables. Results: A total of 91 dengue fever patients were reviewed. The patients age ranged from 4 to 87 years old, and the majority were adult patients. Most patients were farmers and they all had mosquito-biting history. Local cases were the major source of this outbreak. The incubation time was (5.19±2.96) days. All patients had fever over 38 ℃. Thirty-eight (41.8%) patients developed rashes, mainly distributed on the limbs and trunk, and 15 patients (16.5%) developed myalgia and fatigue. The incidence of rashes in patients admitted in September was 15.9% (7/44), which was significantly lower than 68.1% (32/47) in July and August (χ²=25.262, P<0.01). The incidence of headache in patients admitted in September was 27.3%(12/44), which was significantly lower than 78.7% (37/47) in July and August (χ² =24.206, P<0.01). Among the 91 patients, 64 (70.3%) patients had white blood cell counts less than 4×10⁹/L, 14(15.4%) patients had platelet counts less than 50×10⁹/L. The positive rate of dengue non-structural protein 1 (NS1) antigen was 100.0%(37/37), the positive rates of dengue antibody IgM and IgG were 50.0%(11/22) and 13.6%(3/22), respectively. Among the 113 serum samples tested for dengue virus RNA, 106 were identified with dengue virus type-1 and two were dengue virus type-2. In 22 patients who received tests within 7 days, the positive rate of NS1 antigen was 100.0% (22/22), the IgM and IgG positive rates were 50.0%(11/22) and 13.6% (3/22), respectively, and 19 patients were infected with dengue type-1. Among the IgM antibody positive cases, the onset days before sampling was (5.09±1.64) days, longer than that of IgM antibody negative cases ((2.82±1.83) days), with statistical significance (t=3.063, P=0.007). The onset time before sampling in dengue virus RNA-positive group was (3.53±1.87) days, which was shorter than that of RNA-negative group ((6.67±0.58) days), and the difference was statistically significant (t=2.839, P=0.013). Conclusions The dengue fever outbreak cases in Jiangxi Province in 2019 have typical clinical manifestations of dengue fever. Using the NS1 antigen test, IgM and IgG antibody tests and real-time fluorescent quantitative polymerase chain reaction for dengue virus genotyping during early onset of the disease can assistant clinicians in clinical management, controlling infectious source and stopping disease transmission.

Oral diseases concern almost every individual and are a serious health risk to the popula-tion.The restorative treatment of tooth and jaw defects is an important means to achieve oral function and support the appearance of the contour.Based on the principle of"learning from the nature",Deng Xu-liang's group of Peking University School and Hospital of Stomatology has proposed a new concept of"microstructural biomimetic design and tissue adaptation of tooth/jaw materials"to address the worldwide problems of difficulty in treating dentine hypersensitivity,poor prognosis of restoration of tooth defects,and vertical bone augmentation of alveolar bone after tooth loss.The group has broken through the bottle-neck of multi-stage biomimetic technology from the design of microscopic features to the enhancement of macroscopic effects,and invented key technologies such as crystalline/amorphous multi-level assembly,ion-transportation blocking,and multi-physical properties of the micro-environment reconstruction,etc.The group also pioneered the cationic-hydrogel desensitizer,digital stump and core integrated restora-tions,and developed new crown and bridge restorative materials,gradient functionalisation guided tissue regeneration membrane,and electrically responsive alveolar bone augmentation restorative membranes,etc.These products have established new clinical strategies for tooth/jaw defect repair and achieved inno-vative results.In conclusion,the research results of our group have strongly supported the theoretical im-provement of stomatology,developed the technical system of oral hard tissue restoration,innovated the clinical treatment strategy,and led the progress of the stomatology industry.

Background Prolonged awkward postures during occupational activities can lead to excessive musculoskeletal load on the wrist of workers and symptoms such as wrist pain or discomfort. Objective To survey the prevalence of wrist pain among workers in 10 key industries and analyze its correlation with wrist working postures. Methods By using stratified cluster sampling method, workers from 10 key industries, such as footwear manufacturing industry, shipbuilding manufacturing industry, and automobile manufacturing industry, were selected from seven regions in North China, East China, Central China, South China, Southwest China, Northwest China, and Northeast China. The demographic information, wrist working postures, pain in wrist of the workers were collected through a cross-sectional survey. Pearson χ² test was used to compare prevalence by selected factors, trend χ² test for between group comparison, and unconditional logistic regression models for the association of wrist working postures with wrist pain. Results There were 64052 workers enrolled in this survey, and 56286 provided valid questionnaires (the effective rate was 87.8%). According to the survey, the prevalence of wrist pain was 23.3% (13112/56286), and the industries with higher prevalences were footwear manufacturing (27.1%, 1927/7106), automobile manufacturing (24.9%, 5378/21560), and shipbuilding and related equipment manufacturing (24.4%, 850/3488) industries. Finger pinching (OR=2.09, 95%CI: 1.95-2.24), frequent wrist bending (OR=2.03, 95%CI: 1.92-2.15), fixed wrist bending (OR=1.77, 95%CI: 1.69-1.85), wrist on hard edge (OR=1.34, 95%CI: 1.28-1.40), and arms over shoulders (OR=1.11, 95%CI: 1.05-1.17) increased the risk of reporting wrist pain. Conclusion Awkward postures are related to wrist pain among workers in selected 10 key industries. The related factors are wrist on hard edge, frequent wrist bending, finger pinching, fixed wrist bending, and arms over shoulders.