Evaluation of 'surgery-friendly' bone scaffold characteristics: 3D printed ductile BG/PCL scaffold with high inorganic content to repair critical bone defects.

The repair of irregular and complex critical bone defects remains a challenge in clinical practice. The application of 3D-printed bioceramics particle/polymer composite scaffolds in bone tissue engineering has been widely studied. At present, the inorganic particle content of the composite scaffolds is generally low, resulting in poor osteogenic activity. However, scaffold with high inorganic content are highly brittle, difficult to operate during surgery, and cannot be in close contact with surrounding bones. Therefore, it is of great significance to design a 'surgery-friendly' scaffold with high bioceramic content and good ductility. In this study, we used the solvent method to add high concentration (wt% 70%) bioglass (BG) into polycaprolactone (PCL), and polyethylene glycol was used as plasticizer to prepare 70% BG/PCL composite scaffolds with high ductility using 3D printing technology.In vitroexperiments showed that the scaffold had good mechanical properties: easy extension, easy folding and strong compressive resistance. It also showed good performance in biocompatibility and osteogenic activity. It was further observed that compared with pure BG or PCL implantation, the scaffold with higher BG content could have more new bone tissue appeared after 12 weeks. All these results indicate that 3D-printed 70% BG/PCL scaffolds have great potential for personalized repair of bone defects.

Deep Cryogenic Treatment Characteristics of a Deformation-Processed Cu-Ni-Co-Si Alloy.

This paper investigated the influence of deep cryogenic treatments (DCT) on the tensile strength, elongation to fracture and conductivity of a deformation-processed Cu-Ni-Co-Si alloy. The tensile properties were measured using a mechanical testing machine. The conductivity was evaluated using a low-resistance tester. The microstructure and precipitated phases were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), an energy dispersive spectrometer (EDS) and an X-ray diffractometer (XRD). The tensile strength, elongation to fracture and conductivity of the Cu-1.34Ni-1.02Co-0.61Si alloy before and after cold rolling at 47% reduction increased with increasing DCT time and tended to be stable at about 36 h. The microstructure became more uniform after the DCT. The grain size was refined and was smallest after DCT for 48 h. The DCT promoted the precipitation of the solid solution elements Ni, Co and Si from the Cu matrix to form many fine and evenly distributed 20-70 nm spherical second-phase particles in the grains and grain boundaries.

Fortunella venosa (Champ. ex Benth.) C. C. Huang and F. hindsii (Champ. ex Benth.) Swingle as Independent Species: Evidence From Morphology and Molecular Systematics and Taxonomic Revision of Fortunella (Rutaceae).

Recently, the systematic status of Fortunella Swingle and its taxonomy has attracted much attention. Flora of China incorporates Fortunella into Citrus Linn. and treats all species of the traditional Fortunella as one species, namely Citrus japonica (Thunb.) Swingle. Furthermore, F. venosa (Champ. ex Benth.) C. C. Huang and F. hindsii (Champ. ex Benth.) Swingle are currently considered as synonyms of C. japonica. In this paper, morphological, palynological, and phylogenetic analyses were used to systematically explore the taxonomic status of traditional Fortunella. The key morphological features that differed among the Fortunella species were the leaf and the petiole hence could be key in its taxonomic classification of the species. Additionally, pollen morphological analysis based on the pollen size, germination grooves, polar, and equatorial axes also supported the separation of the species. The results of the phylogenetic analysis showed that each of the three species clustered separately, hence strongly supporting the conclusion of independent species. In addition, the phylogenetic analysis showed that the two genera clustered closely together hence our results support the incorporation of Fortunella into Citrus. Based on the above, this article has revised the classification of the traditional Fortunella and determined that this genus has three species, namely; F. venosa, F. hindsii, and F. japonica. F. venosa and F. hindsii are placed in the Citrus as separate species, and their species names still use the previous specific epithet. The revised scientific names of the new combinations of F. venosa and F. hindsii are as follows: Citrus venosa (Champ. ex Benth.) K. M. Liu, X. Z. Cai, and G. W. Hu, comb. nov. and Citrus hindsii (Champ. ex Benth.) K. M. Liu, G. W. Hu, and X. Z. Cai, comb. nov. F. venosa is the original species of Fortunella, F. venosa and F. hindsii are both listed as the second-class key protected wild plants in China. Therefore, the establishment of the taxonomic status of F. venosa and F. hindsii not only deepens our understanding, importance, and the complexity of the systematic classification of Fortunella, but is also significant for global biodiversity conservation, genetic resources for breeding purposes, and population genetics.

Development of ten polymorphic microsatellite loci for Fosbergia shweliensis (Rubiaceae), a potentially crisis endangered tree.

PREMISE OF THE STUDY: Fosbergia shweliensis (Anth.) Tirveng. & Sastre (Rubiaceae) is a potentially endangered tree endemic to China. Microsatellite markers were developed to investigate population genetics of this plant. METHODS AND RESULTS: Ten polymorphic microsatellite loci were identified and screened in 32 individuals from four wild populations of F. shweliensis. Alleles numbered 2 to 5, and their levels of observed heterozygosity and expected heterozygosity ranged from 0.0564 to 0.7214 and from 0.2794 to 0.7912, respectively. CONCLUSIONS: These new microsatellite loci will facilitate further studies of the population genetics of F. shweliensis, allowing us to design reasonable conservation and management strategies.

Synthesis and antiviral activity of 5­(4­chlorophenyl)-1,3,4-thiadiazole sulfonamides.

Starting from 4-chlorobenzoic acid, 10 new 5-(4-chlorophenyl)-N-substituted-N-1,3,4-thiadiazole-2-sulfonamide derivatives were synthesized in six-steps. Esterification of 4-chlorobenzoic acid with methanol and subsequent hydrazination, salt formation and cyclization afforded 5-(4-chlorophen-yl)-1,3,4-thiadiazole-2-thiol (5). Conversion of this intermediate into sulfonyl chloride 6, followed by nucleophilic attack of the amines gave the title sulfonamides 7a-7j whose structures were confirmed by NMR, IR and elemental analysis. The bioassay tests showed that compounds 7b and 7i possessed certain anti-tobacco mosaic virus activity.

[Combined effects of typical natural estrogens with MCF-7 proliferation assay].

OBJECTIVE: To study 17ß-estradiol (E2), ethinylestradiol (EE2), estriol (E3), estrone (E1) on MCF-7 proliferation effects, and compare the effects of independent action (IA) model with concentration addition (CA) model in assessing the combined effects of estrogen. METHODS: The combinations of E2 + EE2, E2 + E3 and E2 + E1 were chosen and the cellular proliferation effects were examined by MTT assay. RESULTS: The maximum proliferation effects at dose of 10⁻9 mol/L was 325.48% for E2, 330.34% for EE2, 255.22% for E3, and 199.61% for E1. In the E2 + EE2, E2 + E3, E2 + E1 groups, the results of IA model analysis were very close to the experimental results. The IA model tend to overestimated the experimental results, while the CA model often underestimated the experimental results. In the EC (E2, 30) + C (EE2, 70) group, the results exceed the maximum estrogen effects of E2, while in other groups, the results were lower. CONCLUSIONS: The estrogenic effects of the four tested substances from high to low efficiency were that: EE2 > E2 > E3 > E1. The effect of IA model in predicting the combined effects of binary mixture was better than CA model. A small proportion of binary mixture showed synergy.

Microstructure and Strengthening Model of Cu-Fe In-Situ Composites.

The tensile strength evolution and strengthening mechanism of Cu-Fe in-situ composites were investigated using both experiments and theoretical analysis. Experimentally, the tensile strength evolution of the in-situ composites with a cold deformation strain was studied using the model alloys Cu-11Fe, Cu-14Fe, and Cu-17Fe, and the effect of the strain on the matrix of the in-situ composites was studied using the model alloys Cu-3Fe and Cu-4.3Fe. The tensile strength was related to the microstructure and to the theoretical strengthening mechanisms. Based on these experimental data and theoretical insights, a mathematical model was established for the dependence of the tensile strength on the cold deformation strain. For low cold deformation strains, the strengthening mechanism was mainly work hardening, solid solution, and precipitation strengthening. Tensile strength can be estimated using an improved rule of mixtures. For high cold deformation strains, the strengthening mechanism was mainly filament strengthening. Tensile strength can be estimated using an improved Hall-Petch relation.

Two complete mitochondrial genomes of Myloplus rubripinnis and Metynnis hypsauchen (Characiforme: Serrasalmidae).

Myloplus rubripinnis and Metynnis hypsauchen are two compressed-bodied ornamental fishes of Serrasalmidae family. In this study, complete mitochondrial genome sequences of the two species were determined. The mitogenomes were 16662 bp and 16737 bp nucleotides in length, and both contained 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNA), 2 ribosomal RNAs (rRNA) and a control region. The phylogenetic tree revealed that Myloplus rubripinnis was closely related to Myleus sp. and Myleus cf. schomburgkii, while Metynnis hypsauchen was related to Pygocentrus nattereri, and then the two clades clustered into one group. Present mitogenome sequences of M. rubripinnis and M. hypsauchen will provide molecular information to the evolution and ecology studies of the two species.

Effects of C Addition on the Microstructures of As-Cast Cu-Fe-P Alloys.

Effects of C addition on the microstructures of as-cast Cu-Fe-P (mass fraction) alloys were systematically investigated. The results show that C addition can refine the matrix microstructure and make Fe particles finer. The Fe particles observed in both the non-C-alloyed and C-alloyed specimens are α-Fe particles, which possess a body-centered cubic (bcc) structure with a Nishiyama-Wassermann orientation relationship with the matrix. C is reported to be an γ-Fe stabilizer in the literature. The reason for the difference between the phases of Fe particles observed in this study, and that reported in the literature, are finally discussed. Additionally, C addition facilitates the decomposition of the supersaturated solid solution which occurs by the simultaneous precipitation of very fine Fe particles. Such initial decomposition product has an face-centered cubic (fcc) structure with a cube-on-cube orientation relationship with the matrix.

[Effects of lead exposure on protein kinase C and calmodulin expression in hippocampus of baby-rats].

OBJECTIVE: To observe the effect of chronic lead contaminant on protein expression of protein kinase (PKC) and calmodulin (CaM) in hippocampus of baby-rats. METHODS: The Wistar pregnant rats were randomly divided into 3 groups fed with distilled water and lead-contained water (0.2% and 1.0% lead acetate) respectively. The lead exposure period ranged from the 0 day of pregnancy to the offspring weaned. Then the baby-rats were fed with lead water the same as their mothers. Pups were killed at postnatal day 8 and 50 respectively. Atomic absorption spectrometry was used to determine lead content of rats' brain. Western-blotting was used to observe protein expression of PKC and CaM in hippocampus of baby-rats. RESULTS: The brain lead content of test groups was much higher than that of the control group in the same growth period (P < 0.01). The content of brain lead in rats of postnatal day 50 was significantly higher than that of rats of postnatal day 8 (P < 0.01). Compared with control group, PKC and CaM protein expressions of chronic lead exposure baby-rats in the hippocampus were down trend (P < 0.05). CONCLUSION: The decrease of PKC and CaM protein expression level in hippocampus might be one of the molecular mechanisms of lead induced impairment of learning and memory.

Effects of an Alternating Magnetic Field/Ag Multi-Alloying Combined Solidification Process on Cu⁻14Fe Alloy.

An alternating magnetic field (AMF)/Ag multi-alloying combined process was applied to the solidification of Cu⁻14Fe alloy to study its effects on the microstructure and properties of the resulting samples. The applied AMF and Ag multi-alloying had positive effects on the refinement of the primary Fe phase and precipitation of Fe solute atoms, respectively. These results indicated that the combined AMF/Ag multi-alloying process was effective to improve the distribution of the primary Fe phase and reduce the Fe content of the Cu matrix, which increased the conductivity of the alloy. The application of the combined AMF/Ag multi-alloying process to the solidification of Cu⁻Fe alloy provided samples with improved comprehensive properties compared with those of samples solidified using a single process (AMF or Ag multi-alloying).

Occurrence and behavior of four of the most used sunscreen UV filters in a wastewater reclamation plant.

Four UV filters, benzophenone-3 (BP-3), 4-methylbenzylidence camphor (4-MBC), ethylhexyl methoxycinnamate (EHMC), and octocrylene (OC), have been examined along the different units of a wastewater reclamation plant (WWRP) located in Tianjin, North China. The analytical procedure included solid-phase extraction and gas chromatographic/mass spectrometric analyses. All four UV filters were detected in the influent during the three sampling campaigns (February, July, and September), and the concentrations ranged from 34 to 2128 ng L(-1). The concentrations of the four UV filters were higher in hot weather (July and September) than in cool weather (February). The monthly average removal ranged from 7.6% to 21% for the selected UV filters during coagulation-flocculation (C-F) treatment. The ozonation treatment achieved the maximum removal (16-28%); on the contrary, the continuous microfiltration (CMF) achieved the lowest removal (3.6-8.2%). The total removal efficiencies along the plant varied from 28% to 43%. These results indicate that the UV filters are not completely removed during WWRP treatment and may be carried over into the environment during the reuse applications.

Protective effects of hepatocellular canalicular conjugate export pump (Mrp2) on sodium arsenite-induced hepatic dysfunction in rats.

Arsenic is a double-edged sword to human health. The excretion of various organic anions into bile is mediated by an adenosine triphosphate-dependent conjugate export pump, which has been identified as the canalicular isoform of the multidrug resistance protein 2 (Mrp2). It has been proved that Mrp2 can transport arsenite in vitro, but its effects in vivo are not clear. The aim of this study was to investigate whether Mrp2 plays a role in exportation of arsenic in vivo and its protective effects on liver function. Mrp2 protein level in rat liver was determined by Western blot analysis. Total arsenic concentrations in whole blood and bile were measured using hydride generation atomic absorption spectrometry. Alanine aminotransferase (ALT) activity, aspartate aminotransferase activity (AST), glutathione peroxidase (GSH-PX) activity, malon dialdehyde (MDA) and total bilirubin were measured by biochemical assays. The morphological changes were observed by electron microscopy. Total arsenic levels in blood and bile of arsenite-treated rats were significantly higher than those of control rats (P<0.05) at all three different time points. The overexpression of Mrp2 was 36.61%, 32.36% and 12.73% at 2, 4 and 6 weeks, respectively (percentage of controls, P<0.05), which was significantly higher than controls. A positive correlation between Mrp2 expression level and total arsenic concentration in bile indicated that Mrp2 accelerated the transport of arsenic. Electron microscopy showed that microvilli of bile canaliculi became swollen and sparse. ALT and AST activities in serum were markedly raised at 6 weeks. MDA level in serum increased (P<0.05) and GSH-PX activity in serum decreased except for 2 weeks. Damage of liver function became worse following decreased expression of Mrp2. In conclusion, overexpression of Mrp2 may explain increased biliary excretion of arsenic and it may protect liver function.

Influence of ethanol-diesel blended fuels on diesel exhaust emissions and mutagenic and genotoxic activities of particulate extracts.

This study was aimed at evaluating the influence of ethanol addition on diesel exhaust emissions and the toxicity of particulate extracts. The experiments were conducted on a heavy-duty diesel engine and five fuels were used, namely: E0 (base diesel fuel), E5 (5%), E10 (10%), E15 (15%) and E20 (20%), respectively. The regulated emissions (THC, CO, NOx, PM) and polycyclic aromatic hydrocarbon (PAH) emissions were measured, and Ames test and Comet assay, respectively, were used to investigate the mutagenicity and genotoxicity of particulate extracts. From the point of exhaust emissions, the introduction of ethanol to diesel fuel could result in higher brake specific THC (BSTHC) and CO (BSCO) emissions and lower smoke emissions, while the effects on the brake specific NOx (BSNOx) and particulate matters (BSPM) were not obvious. The PAH emissions showed an increasing trend with a growth of ethanol content in the ethanol-diesel blends. As to the biotoxicity, E20 always had the highest brake specific revertants (BSR) in both TA98 and TA100 with or without metabolizing enzymes (S9), while the lowest BSR were found in E5 except that of TA98-S9. DNA damage data showed a lower genotoxic potency of E10 and E15 as a whole.

[A comparison study between D-galactose treated mice and natural aging mice].

OBJECTIVE: To explore the feasibility of D-galactose treated mice's implication in aging related study by comparing the difference of all kinds of index between D-galactose treated mice and normal aging mice. METHODS: Kunming mice were used as test animals, which were divided into three groups: D-galactose treated group, normal aging group and young mice group (as control group). Immunology index, including delayed-type hypersensitivity, half hemolysis concentration, plaque forming cell, NK cell activity, were detected. Biochemical index, including malondiadehycle (MDA) concentration, superoxide dismutate (SOD) activity, SOD mRNA and protein, behavior index (mouse water maze test and neurotransmitter) and pathology (conventional pathology and immune histo-chemistry) were also determined. RESULTS: Compared with control group, humoral immunity of normal aging mice was obviously lower, but humoral immunity of D-galactose treated mice showed no difference. Compared with control group, SOD activity was higher and MDA concentration was lower in both D-galactose treated mice and normal aging mice. Behavior tests demonstrated that swimming time extended in different time phase in normal aging mice compare with control group, D-galactose treated group, however, showed no obvious difference. Adrenaline and tissue dopamine in brain tissue of normal aging mice decreased compared with control group, but D-galactose treated mice expressed no difference. And neurotransmitter changes were in accordance with behavior tests. The expression of SOD mRNA level, SOD activity and protein reduced in normal aging group and D-galactose group, compared with control group, which suggested that the downexpression of SOD mRNA was the main cause to the depressed SOD protein expression level and activity. CONCLUSION: D-galactose treated mice were similar to natural aging mouse in some aspects, but there was still big difference between them in immunology and behavior index. D-galactose treated mice is caused by chemical damage and this model is hard to reflect real physiology and biochemistry changes, so it is not a ideal model for immunological and behavioral aging study.

[Study on the genotoxicity of exhausts of diesel engine with ethanol-diesel blending fuel].

OBJECTIVE: To study the genotoxicity of components of diesel engine exhausts with ethanol-diesel blending fuel. To provide scientific arguments to find more economical and less polluted fuels. METHODS: Ames test, comet assay and GC-MS technique were used to test the genotoxicity and 16 kinds of PAHs on diesel engine exhausts with different proportions of ethanol (E0, E5, E10, E20). RESULTS: Both Ames test and comet assay were positive. It shows that diesel engine exhausts can lead to mutation and DNA damage, especially in pure diesel oil. But the content of 16 kinds of PAHs and DNA damage level decreased in exhausts of E5. With the increase of ethanol proportion in diesel oil, the content of 16 kinds of PAHs and DNA damage level increased. CONCLUSION: Compared with pure diesel oil and high proportion of ethanol fuel, E5 can reduce the genotoxicity and the brake specific exhausts of PAHs.

Short selling and intraday volatility: evidence from the Chinese market.

The implementation of margin trading and securities lending mechanism offers us a unique circumstance to analyze the impact of short selling regulations in China. We define the addition events as the stocks are included to the designated securities list and therefore can be sold short. By focusing on the 30 trading days around the addition events, the results document statistically significant post-event increase in volatility relative to the overall market and absolute value of trading volume. Specifically, small-cap stocks experience the sharpest increase. The robustness is also performed to validate the results.

[Study on three kinds of gasoline oxygenates-induced DNA damage in mice fibroblasts].

OBJECTIVE: To study DNA damage of three kinds of gasoline oxygenates. METHOD: Single cell gel electrophoresis assay(Comet assay) was used to detect the damage effects of three gasoline oxygenates[methyl tertiary butyl ether(MTBE), ethanol anhydrous(EA) and dimethyl carbonate(DMC)] on DNA in L-929 mice fibroblasts. RESULTS: In certain concentation(37.500-150.000 mg/ml), MTBE could directly cause DNA damage of L-929 mice fibroblasts. There was obvious dose-effect relationship, i.e. when the concentration of MTBE was increased from 9.375 to 150.000 mg/ml, the comet rate also increased from 4% to 85%, and the length of comet tail changed correspondingly. The results of EA and DMC were negative. CONCLUSION: Under the condition of this experiment(150.000 mg/ml), MTBE could directly cause DNA damage while the effect of EA and DMC on DNA damage was not found.