Photocatalysis Meets Piezoelectricity in a Type-I Oxygen Vacancy-Rich BaTiO3/BiOBr Heterojunction: Mechanism Insights from Characterizations to DFT Calculations.

It is a challenging task to design a piezoelectric photocatalyst with excellent performance under mechanical agitation instead of ultrasonic irradiation. Integrating vacancy defects into a heterojunction seems to be an effective strategy for synergistically increasing its piezo-photocatalytic performance. For this goal, a two-step hydrothermal method was adopted to architect a type-I oxygen-vacancy-rich BaTiO3/BiOBr heterojunction to surge the degradation of Rhodamine B (RhB) under the combined action of simulated sunlight irradiation and mechanical agitation. Various instrumental techniques demonstrated the formation of a BaTiO3/BiOBr heterojunction with high crystallinity. The existence of surface oxygen vacancies was confirmed by XPS and EPR tests. PFM results manifested that this heterojunction had excellent piezoelectric properties, with a piezoelectric response value of 30.31 pm V-1. Comparative experiments indicated that RhB degradation efficiency under piezo-photocatalysis over this heterojunction largely exceeded the total sum of those under piezocatalysis and photocatalysis. h+, ·O2-, and 1O2 were the dominant reactive species for RhB degradation. The improved separation efficiency of photogenerated charges was verified by electrochemical measurements. DFT calculations indicated that the polarization of BaTiO3 could affect the electronic band structure of BiOBr. This work will provide comprehensive insights into piezo-photocatalytic mechanism at a microcosmic level and help to develop new-styled piezoelectric photocatalysts.

Simplicispira sedimenti sp. nov., isolated from a sediment of drainage ditch in winery.

A Gram-stain-negative, motile (by single polar flagellum) and rod-shaped bacterium, designated W1-6T, was isolated from a sediment of drainage ditch in winery in Guiyang, south-western China. Strain W1-6T showed the highest 16S rRNA gene sequence similarities with the type strain of Acidovorax wautersii (98.1%) and Simplicispira lacusdiani (97.9%). Phylogenetic analysis based on 16S rRNA gene sequences showed that strain W1-6T was placed adjacent to the members of the genus Simplicispira and formed a separat subclade. Cells showed oxidase and catalase negative reactions. The only respiratory quinone detected was ubiquinone-8 (Q-8). Summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:0 and summed feature 8 (C18:1 ω7c and/or C18:1 ω6c) were predominant cellular fatty acids (> 10%) of strain W1-6T. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and five unidentified phospholipids were found in the polar lipid extraction. The genomic DNA G + C content was 65.6%. Strain W1-6T shared the highest digital DNA-DNA hybridization [dDDH, (27.6%)] and average nucleotide identity [ANI (84.3%)] values with the type strain of S. lacusdiani. The dDDH and ANI values were below the cutoff level (dDDH 70%; ANI 95-96%) for species delineation. The polyphasic characteristics indicated that the strain W1-6T represents a novel species of the genus Simplicispira, for which the name Simplicispira sedimenti sp. nov. is proposed. The type strain is W1-6T (= CGMCC 1.16274T = NBRC 115624T).

Azospirillum tabaci sp. nov., a bacterium isolated from rhizosphere soil of Nicotiana tabacum L.

Strain W712T was isolated from rhizosphere soil of Nicotiana tabacum L. collected from Kunming, south-west China. Cells were Gram-staining negative, aerobic, motile and rod shaped. The isolate grew at 20-45 °C (optimum 30 °C), pH 6.0-8.0 (optimum pH 7.0) and in the presence of up to 3.0% (w/v) NaCl (optimum 1%, w/v). Ubiquinone-10 was the only respiratory quinone type. Polar lipids contained diphosphatidylglycerol, phosphatidylmehtylethanolamine, phosphatidylglycerol, phosphatidylcholine and an unidentified aminolipid. The major fatty acids were detected as summed feature 8 (C18:1 ω7c or C18:1 ω6c), summed feature 3 (C16:1 ω7c or C16:1 ω6c) and C18:1 2OH. The genomic DNA G + C content was 68.7%. The ANI values were 94.3%, 93.3% and 93.6% between Azospirillum baldaniorum Sp245T, Azospirillum brasilense ATCC 49958T, Azospirillum formosense CC-Nfb-7T and strain W712T, respectively, which were lower than the prokaryotic species delineation threshold of 95.0-96.0%. The digital DNA-DNA hybridization values between A. baldaniorum Sp245T, A. brasilense ATCC 49958T, A. formosense CC-Nfb-7T and strain W712T indicated that the candidate represents a novel genomic species. According to the phenotypic and genotypic characteristics, we propose that strain W712T warrants the assignment to a novel species, for which the name Azospirillum tabaci sp. nov. (type strain W712T = CGMCC 1.18567T = KCTC 82186T) is proposed.

Chthonobacter rhizosphaerae sp. nov., a bacterium isolated from rhizosphere soil of Citrus sinenesis.

A Gram-staining negative, facultative anaerobic, motile and short rod-shaped bacterium, designated strain yh7-1T, was isolated from rhizosphere soil of Citrus sinenesis collected from the garden of Citrus sinenesis in Ailao Mountain, south-west China. Cells grew at 15-45 °C, pH 5.0-9.0 and were able to tolerate up to 1% (w/v) NaCl on R2A medium. The respiratory lipoquinone was Q-10 and the major cellular fatty acids contained summed feature 8 (C18:1 ω7c or C18:1 ω6c) and C18:0. Polar lipids in the cellular membrane were phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and one unidentified aminophospholipid. The genomic DNA G+C content was 69.9 mol%. On basis of 16S rRNA gene sequence analysis, strain yh7-1T showed the highest similarities with Chthonobacter albigriseus KCTC 42450T (97.6%), Mongoliimonas terrestris KCTC 42635T (97.0%) and lower than 97.0% to other species. Phylogenetic trees based on 16S rRNA gene sequences indicated that strain yh7-1T clustered with C. albigriseus KCTC 42450T. The ANI values ranged between 78.1 and 82.7% for C. albigriseus KCTC 42450T, M. terrestris KCTC 42635T and strain yh7-1T, which were lower than the prokaryotic species delineation threshold of 95.0-96.0%. The digital DNA-DNA hybridization values between C. albigriseus KCTC 42450T, M. terrestris KCTC 42635T and strain yh7-1T indicated that the new isolate represents a novel genomic species. According to the phenotypic and genotypic characteristics, strain yh7-1T should belong to the genus Chthonobacter, for which the name Chthonobacter rhizosphaerae sp. nov. (type strain yh7-1T = CGMCC 1.17236T = CCTCC AB 2019258T = KCTC 82185T) is proposed.

Migration sources and pathways of the pest species Sogatella furcifera in Yunnan, China, and across the border inferred from DNA and wind analyses.

The migration sources and pathways of Sogatella furcifera (Horváth) in topologically complex regions like Yunnan, China, and adjacent montane areas have long been a challenging task and a bottleneck in effective pest forecast and control. The present research reinvestigated this issue using a combination of mtDNA and long-term historical wind field data in an attempt to provide new insights. Genetic analyses showed that the 60 populations of S. furcufera collected across Myanmar, Thailand, Laos, Vietnam, Yunnan, Guizhou, and Sichuan lack genetic structure and geographic isolation, while spatial analysis of haplotype and diversity indices discovered geographic relevance between populations. Migration rate analysis combined with high-resolution 10-year wind field analysis detected the following migration sources, pathways, and impacted areas which could explain the outbreak pattern in Yunnan. (a) Dominating stepwise northward migrations originated from northern Indochina, southern Yunnan, and central-eastern Yunnan, impacting their northern areas. (b) Concurring summer-autumn southward (return) migration originated from nearly all latitude belts of Sichuan and Yunnan mainly impacting central and southern Yunnan. (c) Regular eastward and summer-autumn westward migrations across Yunnan. The northward migration reflects the temporal rhythm of gradual outbreaks from the south to the north in a year, while the return migration may explain the repeated or very severe outbreaks in the impacted areas. To form a better pest forecast and control network, attention must also be paid to the northern part of Yunnan to suppress the impact of return migration in summers and autumns.

Pseudorivibacter rhizosphaerae gen. nov., sp. nov., isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze and emended description of the genus Rivibacter.

A Gram-stain-negative, facultative anaerobic, motile and straight rod-shaped bacterium, designated strain C1-9T, was isolated from rhizosphere soil of Camellia sinensis (L.) O. Ktze collected from a tea garden in Huize, south-western PR China. Cells were oxidase-positive and catalase-negative. Growth occurred at 20-40 °C and pH 6.0-10.0, with an optimal growth at 30 °C and pH 7.0. The respiratory quinone was detected as ubiquinone-8 (Q-8). The major fatty acids were identified as summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0 and summed feature 8 (C18 : 1ω7c or C18 : 1ω6c). The cellular polar lipids contained phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, three unidentified phospholipids, two unidentified lipids, one unidentified aminophospholipid and one unidentified aminolipid. The polyamine types were detected as 1,8-diaminooctane and 2-hydroxyputrescine. The genomic DNA G+C content was 68.6 mol%. Based on the results of 16S rRNA gene sequence analysis, strain C1-9T (MF687442) showed highest sequence similarity to Rivibacter subsaxonicus DSM 19570T (97.1 %). The phylogenetic tree based on 16S rRNA gene sequences showed that strain C1-9T clustered close to R. subsaxonicus DSM 19570T, Methylibium petroleiphilum CCTCC AB 2014193T and species belonging to the genera Rhizobacter and Piscinibacter. The phylogenomic tree indicated that strain C1-9T formed a clade with R. subsaxonicus. The average nucleotide identity value was 76.0 % between strain C1-9T and R. subsaxonicus DSM 19570T, which is lower than the prokaryotic species delineation threshold of 95.0-96.0 %. The polyphasic taxonomic characteristics indicated that strain C1-9T represents a novel species of a new genus within the order Burkholderiales, for which the name Pseudorivibacter rhizosphaerae gen. nov., sp. nov. (type strain C1-9T = KCTC 62325T=CGMCC 1.13864T) is proposed.

Identifying Immigrating Sogatella furcifera (Hemiptera: Delphacidae) Using Field Cages: A Case Study in the Yuanjiang (Red River) Valley of Yunnan, China.

The white-backed planthopper, Sogatella furcifera (Horváth), is a devastating migratory rice pest in South China; lack of effective methods to identify immigrating populations is the main cause of difficulties in outbreak forecasting, active prevention, and control. The current study set up field cages (2 × 2 × 3 m each, US-80 standard nylon mesh) in both early- and mid-season paddies in Yuanjiang (Red River) Valley in Yunnan, China, in 2012 and 2014. The immigrating population was successfully separated from the local population of S. furcifera and identified using statistical comparisons. The findings showed that densities of macropterous adults outside the cages were all significantly higher than those inside the cages on both early- and mid-season rice in both years, whereas the densities of young nymphs and old nymphs showed no significant differences. This indicated that immigrations were occurring, the earliest of which occurred on early-season rice in early May and reached its peak in mid-late May before a rapid collapse in both years. In contrast, the immigration on mid-season rice showed a continuous decline or fluctuation throughout the entire period. Analyses demonstrated that the migration process of S. furcifera in the Yuanjiang Valley features continuous immigration from the adjacent southern parts of Yunnan, which may represent most migration events in Yunnan during the outbreak period of a year. The findings of this case study could benefit our understanding of planthopper migration and outbreaks in other parts of China, especially where the outbreak pattern is very different from Yunnan.

Dyella tabacisoli sp. nov., a bacterium isolated from an arable soil sample of Nicotiana tabacum L.

A Gram-stain-negative, aerobic, non-motile and rod-shaped bacterium, designated strain L4-6T, was isolated from an arable soil sample of tobacco in Huize, south-western China and subjected to polyphasic taxonomic characterization. The cells showed oxidase-positive and catalase-positive reactions. Growth occurred at 20-35 °C, at pH 5.0-8.0 and with 0-2 % (w/v) NaCl, optimally at 30 °C, pH 6.0-7.0 and 0-1 % (w/v) NaCl. The major respiratory lipoquinone was ubiquinone-8. The predominant cellular fatty acids (>10.0 %) were identified as summed feature 9 (iso-C17 : 1ω9c or C16 : 0 10-methyl), iso-C15 : 0 and iso-C17 : 0. The polar lipid profile contained diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids, two unidentified aminophospholipids and five unidentified aminolipids. The genomic DNA G+C content was 60.8 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain L4-6T should be affiliated to the genus Dyella and formed a clade with the most closely related organism Dyella soli JS12-10T. 16S rRNA gene sequences similarity analysis showed that strain L4-6T was mostly closely related to D. soli JS12-10T (98.73 %) and Dyella lipolytica DHOB07T (98.02 %). DNA-DNA hybridization data indicated that strain L4-6T represented a novel genomic species belonging to the genus Dyella. The polyphasic taxonomic characteristics indicated that the strain L4-6T represents a novel species of the genus Dyella, for which the name Dyellatabacisoli sp. nov. (type strain L4-6T=CGMCC 1.16273T=KCTC 62035T) is proposed.

Porous zirconia ceramic as an alternative to dentin for in vitro dentin barriers cytotoxicity test.

OBJECTIVES: This study assessed the potential of porous zirconia ceramic as an alternative to dentin via an in vitro dentin barrier cytotoxicity test. METHODS: The permeability of dentin and porous zirconia ceramic was measured using a hydraulic-conductance system, and their permeability was divided into two groups: high and low. Using an in vitro dentin barrier test, the cytotoxicity of dental materials by dentin and porous zirconia ceramic was compared within the same permeability group. The L-929 cell viability was assessed by MTT assay. RESULTS: The mean (SD) permeability of the high and low group for dentin was 0.334 (0.0873) and 0.147 (0.0377) µl min-1 cm-2 cm H2O-1 and for zirconia porous ceramic was 0.336 (0.0609) and 0.146 (0.0340) µl min-1 cm-2 cm H2O-1. The cell viability of experimental groups which are the low permeability group was higher than that of the high permeability group for both dentin and porous zirconia ceramic as a barrier except for Maxcem Elite™ by porous zirconia ceramic. There was no significant difference between dentin and porous zirconia ceramic in cell viability, within either the high or low permeability group for all materials. The SD for cell viability of the porous zirconia ceramic was less than that of the dentin, across all materials within each permeability group, except for Maxcem Elite™ in the high permeability group. CONCLUSIONS: Porous zirconia ceramic, having similar permeability to dentin at the same thickness, can be used as an alternative to dentin for in vitro dentin barrier cytotoxicity tests. CLINICAL RELEVANCE: In vitro dentin barrier cytotoxicity tests when a standardized porous zirconia ceramic was used as a barrier could be useful for assessing the potential toxicity of new dental materials applied to dentin before applying in clinical and may resolve the issue of procuring human teeth when testing proceeds.

Sphingobacterium tabacisoli sp. nov., isolated from a tobacco field soil sample.

A Gram-staining-negative, non-motile and rod-shaped bacterium, designated strain h337T, was isolated from an arable soil sample of a tobacco field in Kunming, south-west China. The cells showed oxidase-positive and catalase-positive reactions. Growth was observed at 10-35 °C, at pH 6.0-9.0 and in the presence of up to 3 % (w/v) NaCl, with optimal growth at 30 °C, pH 7.0 and with 1-2 % (w/v) NaCl. The predominant isoprenoid quinone was MK-7. The major fatty acids were identified as iso-C15 : 0, iso-C17 : 0 3-OH, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B). The cellular polar lipids contained phosphatidylethanolamine, sphingophospholipid, four unidentified phospholipids, five unidentified lipids and three unidentified aminophospholipids. The genomic DNA G+C content was 41.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain h337T should be assigned to the genus Sphingobacterium. 16S rRNA gene sequence similarity analysis showed that strain h337T was most closely related to 'Sphingobacteriumyamdrokense' 3-0-1 (98.8 %) and Sphingobacteriumyanglingense CCNWSP36-1T (98.5 %) and shared less than 97 % similarity with other species of the genus Sphingobacterium. DNA-DNA hybridization data indicated that the isolate represented a novel genomic species belonging to the genus Sphingobacterium. The characteristics determined in this polyphasic taxonomic study indicated that strain h337T represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium tabacisoli sp. nov. (type strain h337T=KCTC 52298T=CCTCC AB 2017155T) is proposed.

Quasi-static and ratcheting properties of trabecular bone under uniaxial and cyclic compression.

The quasi-static and ratcheting properties of trabecular bone were investigated by experiments and theoretical predictions. The creep tests with different stress levels were completed and it is found that both the creep strain and creep compliance increase rapidly at first and then increase slowly as the creep time goes by. With increase of compressive stress the creep strain increases and the creep compliance decreases. The uniaxial compressive tests show that the applied stress rate makes remarkable influence on the compressive behaviors of trabecular bone. The Young's modulus of trabecular bone increases with increase of stress rate. The stress-strain hysteresis loops of trabecular bone under cyclic load change from sparse to dense with increase of number of cycles, which agrees with the change trend of ratcheting strain. The ratcheting strain rate rapidly decreases at first, and then exhibits a relatively stable and small value after 50cycles. Both the ratcheting strain and ratcheting strain rate increase with increase of stress amplitude or with decrease of stress rate. The creep model and the nonlinear viscoelastic constitutive model of trabecular bone were proposed and used to predict its creep property and rate-dependent compressive property. The results show that there are good agreements between the experimental data and predictions.

[Time-related expression of IL-6, IL-8 and TNF-alpha following explosive injury to rabbit's chest].

OBJECTIVE: To explore the relationship between the expression changes of cytokines, interleukin-6 (IL-6), interleukin-8(IL-8), and tumor necrosis factor-alpha (TNF-alpha), and the wound time following explosive injury to rabbit's chest. METHODS: The rabbit's model of explosive injury was established. The expression levels of IL-6, IL-8 and TNF-alpha in the plasma were detected by ELISA method at different wound time (0.5-12h). RESULTS: The level of IL-6 increased at 3h after wounding and reached peak at 6 h. The level of IL-8 increased at 1 h and reached peak at 6 h. The level of TNF-alpha increased at 0.5 h and reached peak at 3 h. CONCLUSION: IL-6, IL-8 and TNF-alpha have a time-related expression after explosive injury.

[Sudden cardiac death of incarcerated prisoners: a study of 75 cases].

OBJECTIVE: To investigate the characteristics and influencing factors leading to sudden cardiac death (SCD) of incarcerated prisoners. METHODS: Seventy-five SCD cases of prisoners between 2000 and 2013 in Henan province were collected, and environment, psychological and physical factors were retrospectively analyzed. Combined with histopathological results, specific factors of SCD were also studied. RESULTS: In the 75 cases, 21 cases (28%) had definite chronic past medical histories, and 75 cases (100%) had cardiovascular disease confirmed by autopsy. CONCLUSION: Due to presence of the potential cardiac diseases, special incarcerated environment, psychological stress, and body-restraint might be the precipitating factors in SCD of those prisoners.

Delivering MC3T3-E1 cells into injectable calcium phosphate cement through alginate-chitosan microcapsules for bone tissue engineering.

OBJECTIVE: To deliver cells deep into injectable calcium phosphate cement (CPC) through alginate-chitosan (AC) microcapsules and investigate the biological behavior of the cells released from microcapsules into the CPC. METHODS: Mouse osteoblastic MC3T3-E1 cells were embedded in alginate and AC microcapsules using an electrostatic droplet generator. The two types of cell-encapsulating microcapsules were then mixed with a CPC paste. MC3T3-E1 cell viability was investigated using a Wst-8 kit, and osteogenic differentiation was demonstrated by an alkaline phosphatase (ALP) activity assay. Cell attachment in CPC was observed by an environment scanning electron microscopy. RESULTS: Both alginate and AC microcapsules were able to release the encapsulated MC3T3-E1 cells when mixed with CPC paste. The released cells attached to the setting CPC scaffolds, survived, differentiated, and formed mineralized nodules. Cells grew in the pores concomitantly created by the AC microcapsules in situ within the CPC. At Day 21, cellular ALP activity in the AC group was approximately four times that at Day 7 and exceeded that of the alginate microcapsule group (P<0.05). Pores formed by the AC microcapsules had a diameter of several hundred microns and were spherical compared with those formed by alginate microcapsules. CONCLUSIONS: AC microcapsule is a promising carrier to release seeding cells deep into an injectable CPC scaffold for bone engineering.

Numerical simulation research to both the external fixation surgery scheme of intertrochanteric fracture and the healing process, and its clinical application.

In this paper, the single arm external fixation of intertrochanteric fracture healing process after surgery was simulated to obtain a postoperative fracture healing and stress distribution in the external fixator. Firstly CT images of intertrochanteric fracture are reconstructed into the femur solid model. Then based, the external fixator is installed on the model, which lastly formed a finite element model of unilateral external fixation for intertrochanteric fracture. The calculated results show: during the beginning of the fracture healing, there is much higher stress in both screws and femur in the model with solid screws than that in the model with hollow screw. The stress of the femur in the model with hollow screw is more evenly. During the middle time of Fracture healing, stress in the femoral head significantly decreases. And the stress at fracture site gradually increased with the healing occurrence. According to the results, the authors designed hollow screws to use external fixation surgery. Surgery confirmed that the use of hollow screws in fractures treatment can satisfy the strength requirements, and can effectively reduce operative time, less patient suffering. The research for external fixation can provide a reference, and promote the use of external fixation hollow screws.

[A retrospective analysis of 105 drowning victims with psychiatric disorders].

OBJECTIVE: To analyze the features of drowning victims with psychiatric disorders to support further investigation on such cases. METHODS: One hundred and five archives of drowning victims with psychiatric disorders from January 2010 to June 2014 in Harbor Public Security Subbureau, Shanghai Public Security Bureau were reviewed. The decedents' general information, autopsy findings, case investigation data and disease histories were statistically analyzed. RESULTS: Of the 105 cases, 104 were suicides. Most decedents were poorly educated. Most suicides occurred in warm climate, and the corpses were usually found within 2 days. Most decedents had no suicide history and notes, but had abnormal mental or behavior changes before suicide. Depression, depression status and schizophrenia were the main types of psychiatric disorders, and only 9 decedents had received regular therapies before their deaths. CONCLUSION: Mental disorder is a high risk factor in the drowning victims. Guardians should be aware of psychotic abnormal behaviors, especially during warm climate seasons.

[Poisoning by exhaust gas of the imperfect combustion of natural gas: 22 cases study].

OBJECTIVE: To analyze the case characteristics of poisoning by exhaust gas of the imperfect combustion of natural gas and provide references for forensic identification and prevention of such accidents. METHODS: Twenty-two cases of poisoning by exhaust gas of the imperfect combustion of natural gas in Minhang District during 2004 to 2013 were collected. Some aspects such as general conditions of deaths, incidence time, weather, field investigation, and autopsy were retrospectively analyzed. RESULTS: In the 22 cases, there were 15 males and 16 females. The age range was between 2 and 82 years old. The major occurring time was in January or February (8 cases in each) and the cases almost occurred in small area room (21 cases). There was wide crack next to the exhaust port when the gas water heater was been used in all cases. CONCLUSION: There are more prone to occurrence of exhaust gas poisoning of imperfect combustion of natural gas in small area room with a ventilation window near the exhaust port of gas water heated. It shows that the scene of combustion exhaust gas poisoning should be more concerned in the cold season.

[Protective role of calcium alginate hydrogel beads in cells during calcium phosphate cement setting reaction and its influencing factors].

OBJECTIVE: To evaluate the protection of calcium alginate hydrogel beads for mouse preosteoblastic cell line (MC3T3-E1) during the setting reaction of calcium phosphate cement (CPC) pastes and to analyze related influencing factors. METHODS: The MC3T3-E1 cells encapsulated in alginate hydrogel beads were cultured in vitro with ß-tricalcium phosphate/calcium phosphate cement (ß-TCP/CPC) pastes and discs until 2 d. The cell viability and number of live/dead cells were tested using the CCK-8, Calcein-AM and PI, respectively. The effects of CPC paste and CPC disc, different treatment and time to renewal medium on cell viability were compared. RESULTS: There were no significant differences in optical density and number of live cells between ß-TCP/CPC pastes and discs (1 d: P=0.827; 2 d: P=0.965). There were different influences on cell viability between different treatment and time to renewal medium. CONCLUSION: The results indicated that the calcium alginate hydrogel beads had a good protection to MC3T3-E1 cells during the setting reaction of CPC pastes. CPC paste might affect the cell proliferation even when solidification. After setting reaction, it may be favorable for cell viability to renew the medium every 6 h in 1 d.

[Research on the osteogenic ability of 3-Ds interconnected porous titanium].

OBJECTIVE: To evaluate the osteogenic ability of the three-dimensional interconnected porous titanium(TDIPT) coated with bonelike apatite, by the test of the culture of osteoblast in vitro. METHODS: The pure TDIPT was prepared by the high temperature insostatic pressing (HIP) and was divided into two groups. One group of TDIPT was dipped into the 1.5 simulated body fluid (1.5 SBF) and developed the TDIPT coated with bone-like apatite (The test group). Another group was control group (pure TDIPT). The porous titanium of the two groups were all made into standard parts (5 mm x 5 mm x 4 mm) and placed into the 24-hole plates. The osteoblasts were extracted from SD rat. After the primary culture and subculture of the osteoblast in vitro, the osteoblasts were inoculated into the samples in the 24-pole plate and cultured continually. MTT Cell Proliferation Assay was done on the 1st, 3rd, 5th, 7th and 9th day respectively after inoculating. The ALP activity was tested on the 7th, 14th and 21st day, respectively. The collected data were analyzed by use of the student t test. RESULTS: The MTT value and the ALP activity increased with the increasing of the culture time in the two group, but those of the test group was more significant than those of the control group (P < 0.05). Moreover, the osteoblast tachyauxesis and stable adhesion were observed in test group by SEM at the 7th day after culturing. CONCLUSION: The bioactivity of the TDIPT improves significantly after coating with the bone-like apatite onto the surface of the TDIPT.

[Cytological study on osteoblasts and in-situ setting calcium phosphate cements].

OBJECTIVE: To evaluate biocompatibility of three kinds of self-developed injectable calcium phosphate cements (CPCs): chitosan microspheres/CPC, ß-tricalcium phosphate (ß-TCP)/CPC, and K(+)/CPC and the viability of the osteogenic cells cultured with CPC pastes and discs for 10 days. METHODS: The rabbit marrow stromal cells (rMSCs), isolated from rabbit bone marrow with density gradient centrifugation and flow cytometer, were cultured, expended and induced into osteoblasts. Alizarin red staining was used to determine the function of ossification. Then, rMSCs were incubated randomly on both the pastes and solidified discs of the 3 kinds of CPCs. The cells cultured on a 24-well plate were as blank control. Each group had 4 samples. The proliferation and differentiation of each group were observed using acid phosphatase assay (APA) and by testing the activity of alkaline phosphatase (ALP) at day 1, 4, 7, and 10. After stained by acridine orange(AO), the cells were observed, counted and analyzed with an epifluorescence microscopy. The morphology of the cells on CPCs was observed with scanning electron microscope(SEM).The data was subjected to two-way ANOVA followed by LSD test to compare between groups. RESULTS: The process of solidification of the three kinds of CPC pastes has the toxic effect on cells, which is irreversible. The proliferation( the average absortion of pastes are 0.049,0.050,0.049; the discs are 0.898,0.867,0.909;P<0.001), function(the average ALP activity of pastes after ten days are 0.775,0.782,0.798 U/g protein; the discs are 49.288,49.631, 49.744 U/g protein;P<0.001) and number of cells(the average number of cells of pastes after ten days are 3.7,3.7,3.7; the discs are 91.1,89.7,93.7;P<0.001) directly exposed to CPC paste significantly decreased compared with those contacting with the discs. By contrast, cells on the three kinds of discs showed better viability, proliferation, and ossification and cell numbers increased obviously with culture days. CONCLUSION: The process of solidification of the three kinds of CPC pastes has toxic effect on cells. Further study needs to explore a method to protect osteoblasts when seeded into the CPC paste.