Microstructure and elastic modulus evolution of TiTaNb alloys.

In order to develop Ti based alloys with promising biocompatibility and matching mechanical response with human bone, TiTaNb alloys with 15, 23 and 30 mass% Ta are designed and systematically examined in terms of microstructural evolution and mechanical response. The Ti-30mass%Ta-10mass%Nb is demonstrated to be satisfactory with an elastic modulus ~60 GPa, hardness ~3.1 GPa, and strength ~1250 MPa. The evolution trend of the resulting microstructure and phases as a function of Ta content and annealing temperature are established. The relationship between the various phase amounts and alloy moduli is explored.

Nanoporous foam fabricated by dealloying AgAl thin film through supercritical fluid corrosion.

In this research, nanoporous silver foams are fabricated through dealloying Ag35Al65 (as atomic percentage, at%) thin films in supercritical (SC) carbon dioxide. The supercritical CO2 is mixed with either HCl, water or H2C2O4 aqueous solution as the solute in the reaction chamber. Due to the low tension of the supercritical fluid, under the best operating conditions, the surface area of the as-dealloyed Ag35Al65 can reach 4.6 m2 g-1, and the porosity volume fraction value can reach 74%, with a smallest average pore size of around 75 nm. In an optimum supercritical CO2 environment, a lower chemical concentration can be applied and it can take less time to form a uniform nanoporous structure.

Effects of the 3D bone-to-implant contact and bone stiffness on the initial stability of a dental implant: micro-CT and resonance frequency analyses.

This study investigated the effects of bone stiffness (elastic modulus) and three-dimensional (3D) bone-to-implant contact ratio (BIC%) on the primary stabilities of dental implants using micro-computed tomography (micro-CT) and resonance frequency analyses. Artificial sawbone models with five values of elastic modulus (137, 123, 47.5, 22, and 12.4 MPa) comprising two types of trabecular structure (solid-rigid and cellular-rigid) were investigated for initial implant stability quotient (ISQ), measured using the wireless Osstell resonance frequency analyzer. Bone specimens were attached to 2 mm fibre-filled epoxy sheets mimicking the cortical shell. ISQ was measured after placing a dental implant into the bone specimen. Each bone specimen with an implant was subjected to micro-CT scanning to calculate the 3D BIC% values. The similarity of the cellular type of artificial bone to the trabecular structure might make it more appropriate for obtaining accurate values of primary implant stability than solid-bone blocks. For the cellular-rigid bone models, the ISQ increased with the elastic modulus of cancellous bone. The regression correlation coefficient was 0.96 for correlations of the ISQ with the elasticity of cancellous bone and with the 3D BIC%. The initial implant stability was moderately positively correlated with the elasticity of cancellous bone and with the 3D BIC%.

Using a bubble chart to enhance adherence to quality-of-care guidelines for colorectal cancer patients.

This study examines whether a higher rate of physician adherence to quality-of-care indicators for colorectal cancer patients is associated with improved survival and using a bubble chart to help interpret physician performance. A set of 13 core measures was used to evaluate the quality of care in 708 colorectal cancer patients treated from 2004 to 2007 at a hospital in Taiwan. A 100% adherence standard was used to measure the relationship of adherence to patient survival. Each indicator assigned by each cancer stage was dichotomously coded. The associations between the adherence and survival rates and demographic characteristics were assessed using Cox's proportional hazard regression. Physician adherence to core indicators was plotted using a bubble chart to motivate physicians' performance adhering to quality-of-care guidelines for colorectal cancer patients. The 100% adherence rate criterion contributed to a relatively low hazard ratio of 0.36 (95% confidence interval, 0.14-0.85; P= 0.02). The association between the adherence rate and survival indicated significant improvements for stage III patients compared with stage I patients. A graphical representation of bubble charts helped to monitor physician performance, which improved the adherence rate to quality-of-care guidelines for colorectal cancer patients.

Bacterial community composition in Brazilian Anthrosols and adjacent soils characterized using culturing and molecular identification.

Microbial community composition was examined in two soil types, Anthrosols and adjacent soils, sampled from three locations in the Brazilian Amazon. The Anthrosols, also known as Amazonian dark earths, are highly fertile soils that are a legacy of pre-Columbian settlement. Both Anthrosols and adjacent soils are derived from the same parent material and subject to the same environmental conditions, including rainfall and temperature; however, the Anthrosols contain high levels of charcoal-like black carbon from which they derive their dark color. The Anthrosols typically have higher cation exchange capacity, higher pH, and higher phosphorus and calcium contents. We used culture media prepared from soil extracts to isolate bacteria unique to the two soil types and then sequenced their 16S rRNA genes to determine their phylogenetic placement. Higher numbers of culturable bacteria, by over two orders of magnitude at the deepest sampling depths, were counted in the Anthrosols. Sequences of bacteria isolated on soil extract media yielded five possible new bacterial families. Also, a higher number of families in the bacteria were represented by isolates from the deeper soil depths in the Anthrosols. Higher bacterial populations and a greater diversity of isolates were found in all of the Anthrosols, to a depth of up to 1 m, compared to adjacent soils located within 50-500 m of their associated Anthrosols. Compared to standard culture media, soil extract media revealed diverse soil microbial populations adapted to the unique biochemistry and physiological ecology of these Anthrosols.

Systematic search for mutations in the human tissue inhibitor of metalloproteinases-3 (TIMP-3) gene on chromosome 22 and association study with schizophrenia.

Several linkage studies have suggested that chromosome 22q12-q13 is a putative region for schizophrenic genes. In this study, the human tissue inhibitor of metalloproteinase-3 (TIMP-3) gene was investigated as positional candidate gene for schizophrenia because of its regulatory function on extracellular matrix proteins, cell adhesion molecules, and neural cell adhesion molecules in the brain. We systematically searched for the nucleotide variants by sequencing all the exons and their flanking intronic sequences in a sample of Chinese schizophrenic patients from Taiwan. Two silent mutations in the exon 3 were identified: c.249T-->C at codon 83 (His) and c.261C-->T at codon 87 (Ser). However, no mutations causing amino acid alteration or aberrant splicing of transcripts were observed. Hence, it is unlikely that the TIMP-3 gene itself may play an important role in the genetic susceptibility to schizophrenia. Further case control association study revealed a significant difference of genotype distribution of the c.249T-->C between schizophrenic patients and control. This finding supports that 22q12 is a schizophrenia susceptible region, and it is likely that there might be other genetic mutations in the neighborhood of the TIMP-3 gene locus that may contribute to the susceptibility of schizophrenia.

Lack of evidence to support the association of the human prion gene with schizophrenia.

Recently a new variant of Creutzfeldt-Jakob disease, a human prion disease, with prominent psychiatric manifestations in the early stage was identified, suggesting that human prion disease may be associated with mental disorders. Furthermore, a novel missense mutation with asparagine-to-serine substitution at codon 171 of the human prion gene (N171S) was identified in a family with severe psychiatric symptoms. This finding provides further clue that the prion gene may be a susceptibility gene for certain psychiatric disorders. We systematically sequenced the protein-coding and untranslated exons of prion gene in 62 Han Chinese schizophrenic patients with positive family history from Taiwan. We identified two polymorphisms that alter amino acid sequences, a methionine/valine at codon 129 (M129V) and a glutamate/lysine at codon 219 (E219K), respectively. Further comparison of the genotype, allele and haplotype frequency distributions of these two polymorphisms between 234 schizophrenic patients and 100 non-psychotic controls, however, did not reveal significant differences between two groups. Besides, no other mutations in the prion gene were identified in these 62 patients. Hence, our results suggest that the prion gene may not play a major role in conferring susceptibility to schizophrenia.

Mutation analysis of the human NR4A2 gene, an essential gene for midbrain dopaminergic neurogenesis, in schizophrenic patients.

Recent studies have revealed that an orphan receptor gene of the steroid/thyroid hormone nuclear receptor superfamily, the Nurr1 gene, is essential for the neurogenesis and differentiation of dopaminergic neurons in the midbrain of mice. Transgenic mice lacking the Nurr1 gene soon die after birth and are devoid of dopaminergic neurons in the midbrain. Heterozygous mice survive postnatally without obvious locomotor deficits; however, they have increased vulnerability to dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). In view of the importance of dopamine neurotransmission in brain function, we were interested to know if the human homologous gene of murine Nurr1, the NR4A2 gene, may play a role in the pathogenesis of schizophrenia. We systematically sequenced all the exons of the human NR4A2 gene to search for molecular variants in a cohort of Chinese schizophrenic patients from Taiwan. Two molecular variants were identified: a G-insertion in intron 6 (designated IVS6 + 17 [see text] + 18insG), and a G-deletion in the untranslated exon 1 (designated c.-469delG). The IVS6 + 17 [see text] + 18insG is a polymorphic one; further case control study, however, did not reveal association of this polymorphism with schizophrenia. The c.-469delG is a rare variant found in two unrelated patients among 177 schizophrenic patients, but not in 130 nonpsychotic controls. The result suggests that the c.-469delG and possibly other variants of the NR4A2 gene may be of relevance to the complex factors involved in the pathogenesis of schizophrenia.

Alteration in the expression of protein kinase C isoforms in human hepatocellular carcinoma.

This study was designed to investigate the alterations of individual protein kinase C (PKC) isoforms in human liver cancer. Surgical specimens of hepatocellular carcinoma and adjacent normal tissues were extracted into cytosolic and membranous fractions. The level of membrane-bound PKCalpha in the cancer tissue was significantly lower than that in the adjacent normal tissue and consistent with the change in PKC activity. In addition, there was a significant negative correlation between PKCalpha and tumor size. In both cytosolic and membrane fractions, levels of PKCdelta and PKCzeta was significantly higher in the cancer tissue than those in the adjacent normal liver tissue. The alterations in the PKC isoforms signify their roles in the hyperproliferation in liver cancer.

Detection of Borna disease virus RNA from peripheral blood cells in schizophrenic patients and mental health workers.

Accumulating evidence suggests that Borna disease virus (BDV), a neurotropic, negative-stranded RNA virus, might be associated with certain human mental disorders. Several research groups reported that psychiatric patients had a significantly higher prevalence of BDV serum antibodies than normal controls. In addition, a significantly higher presence of BDV RNA from peripheral blood cells was identified in mental patients than in controls. In our previous study, we first identified the presence of BDV serum antibodies in a cohort of Chinese schizophrenic patients from Taiwan, and we also demonstrated a significantly higher seroprevalence of BDV antibodies among schizophrenic patients than in non-psychiatric controls. Prompted by the positive seroepidemiological result, we set out to investigate the detection of BDV RNA from the peripheral blood cells of our schizophrenic patients. By using the reverse transcription-polymerase chain reaction (RT-PCR) method, 10 out of 74 Chinese schizophrenic patients from Taiwan were found to have BDV RNA in their blood cells, whereas only one out of 69 controls was positive. The BDV RNA detection rate among schizophrenic patients was significantly higher than that in controls (14% vs 1.4%, P < 0.01). Furthermore, we studied the BDV RNA detection rate among mental health workers, and seven out of 45 mental health workers were found to have positive results. The prevalence rate was significantly higher than that in normal controls (15% vs 1.4%, P < 0.001), which lends further support to our previous finding that mental health workers have a significantly higher presence of BDV serum antibodies. In summary, our data support the finding that BDV infection might be a contributory factor to the pathogenesis of schizophrenia in the Chinese population.

Genetic association study of a polymorphic CAG repeats array of calcium-activated potassium channel (KCNN3) gene and schizophrenia among the Chinese population from Taiwan.

Chandy et al suggested that a novel human neuronal small conductance, calcium-activated potassium channel gene, KCNN3, might be a candidate for schizophrenia. The KCNN3 cDNA sequences contain two stretches of CAG trinucleotide repeats encoding two separate polyglutamine segments near the N-terminus of this channel protein. The second CAG repeat was found to be highly polymorphic in the Caucasian population from both Europe and USA. Upon comparing the allelic frequency distribution between schizophrenic patients and ethnically matched controls, a significant excess of longer CAG repeats in schizophrenic patients was observed. A similar result was obtained in a recent replication study by Bowen et al, performed in Caucasians from UK or Eire. These results suggest an association between the longer CAG repeat allele of the KCNN3 gene and schizophrenia susceptibility. To verify if similar results can be observed in the Chinese population, we carried out a case-control study to compare the allelic frequency distribution of the CAG repeat of the KCNN3 gene between 92 Chinese schizophrenic patients and 100 normal controls from Taiwan. No significant difference of the allelic frequency distribution of the second CAG repeats was detected between the two groups (Wilcoxon Rank Sum test, P = 0.664). In addition, no over-representation of CAG repeats longer than the mode (19 repeats) was found in the patients' group (Fisher's exact test, P = 0.739). Thus, our data do not support that the second polymorphic CAG repeat of the KCNN3 gene may have an association with schizophrenia in our population.

The effect of pentoxifylline on cochlear blood flow.

Pentoxifylline, a phosphodiesterase inhibitor and hemorrheologic agent has been found to increase oxygen delivery to ischemic tissue. Intravenous pentoxifylline was administered to normal guinea pigs in order to assess the effect of pentoxifylline on cochlear blood flow and to elucidate its mechanism of action. Intravenous pentoxifylline was found to acutely increase cochlear blood flow in a dose-dependent manner. In normal animals, the effect appeared strongly related to the rheologic properties of this agent rather than a vasodilative action. Normovolemic hemodilution with 75% dextran resulted in no increase in cochlear blood flow during infusion of pentoxifylline, whereas the application of nitroprusside over the round window failed to abolish the effect of pentoxifylline.