The Effects of Zirconia Additions on the Sintering Behaviour and Phase Stability of Hydroxyapatite Ceramics

Hydroxyapatite-zirconia composites with different ratios were prepared by using the conventional ball-milling technique. Ceramic pellets prepared from these powders were compacted and sintered without distorting or cracking. The sintering behaviour (at 1250'C, 1400'C and 1600'C) of the composites were studied in terms of phase stability, densification and microstructural evolution. By X-ray diffraction, tetragonal zirconia as well as HA was identified as the major phases in the composites. In addition, small diffraction peaks corresponding to a-TCP was evident indicating sign ofHA decomposition. Reaction between the zirconia and HA to form caZro. was also detected in the composite system containing up to 20 wt% zirconia throughout the sintering regime employed. SEM examination of the sintered composites at room temperature suggested the involvement of a reactive liquid phase during sintering. The presence of zirconia phase in hydroxyapatite matrix played an important role in the stability of the HA phase

Saccharomyces cerevisiae kinetochore protein (rDsn1p) induced apoptosis in Chinese hamster ovary cells

Dsn1p is a member of the MIND complex that forms part of the yeast kinetochore, which is essential for the proper chromosomal segregation during cell division. Its functionality is gene dosage dependent and it has characteristics of haploinsufficiency. Bioinformatics alignments predicted the existence of nuclear homologues in higher eukaryotic organisms. Literature on the possibility of Dsn1p being a functional homologue of these organisms is scarce. In this study we employed recombinant DNA expression technology to explore whether Dsn1p can function in a mammalian cell line, Chinese Hamster Ovary (CHO). Expression of rDsn1p in CHO cells induced cytopathic effects including changes in cellular morphology and cell size. Inhibition of cell growth was observed at the beginning the fourth post-transfection week. The recombinant CHO cell culture showed cytotoxic effects following the accumulation of the Dsn1p, resulting in apoptotic cell death; as evidenced by the presence of nuclear fragmentation and surface blebbing in the dying cells. This suggests that rDsn1p may interact with the counterpart/ligand of the nuclear homologue of this protein in CHO cells, resulting in nuclear anomalies and inhibition of cell growth, as observed in our previous study using yeast cells

Cold bonded pelletization of iron ore fines

Cold bonding processes have been developed with a view to conserve energy in pellet hardening step. The incorporation of the reductant and fluxes in the pellet also ensures a blast furnace burden that is hanogeneous with resultant smooth operations of the furnace. The present paper deals with the studies conducted on tha production of ccmposite iron are pellets using iron are fines, leco char. hydrated lime and natural silica flour as well as rice husk silica. The results indicate that the composite pellets with rice husk has superior strength compared to the pellets with natural crystalline form of silica. Studies on CaO-HZD-rice husk silica reaction systffil revealed that a gel like calciun silicate hydrate (CSH-I) is formed during the steaming operation that is responsible for the strengthaning of the composite pellet. The studies on the kinetics of the hydrothermal reaction revealed that the reaction is diffusion controlled and the product fanned is calcium silicate hydrate. The reducibility studies indicated good reducibility with minimun swelling

Insilico modeling of chitosan as a drug delivery system

Computational modeling of polymeric nanoparticles as drug carriers have been extensively studied due to their varied functionalities, tunable structures and the capability of controlled drug release. Nano particulate polymeric drug delivery systems enable a cell specific targeting with negligible side effects and drug release based on change in physiological conditions. Eight common polymers are modeled and the various properties have been predicted. ADMET, QSAR, thermodynamic and electronic properties have been predicted and compared using SAR as well as quantum mechanical density functional methods. Comparison of the predicted properties suggests that chitosan, which is a natural polymer and has some advantages over others is a promising drug carrier candidate for tumor

Diurnal activity of the prawn Penaeus semisulcatus De Haan

Several authors have reported that penaeid prawns remain active above substratum at night and stay quiet, buried in sand during the day (Fuss, 1964; Fuss and Ogren, 1966 ; Wickham, 1967; Hughes, 1968). Menon and Raman (1961) also suggested increased nocturnal activity in Indian penaeid prawns. Kutty (1967) pointed out the burrowing habit of Penaeus semisculcatus and estimated the metabolism of the buried prawn; his short term observations, however, did not indicate that Penaeus indicus has the burrowing habit. Burrowing methods of Metapenaeus masiersii have been described by Dall (1958) and those of Penaeus duorarunt by Fuss (1964). It appears that the burrowing habits of the penaeid prawns are more or less similar. As evident, precise information on the burrowing behaviour, emergence from the substratum and activity of the Indian prawns are wanting. The authors had occasion to observe the activity rhythm of a group of penaeid prawns, Penaeus semisulcatus reared in the sea water aquarium of the Institute primarily for a series of experiments on metabolic adptations. The present observations, though not strictly planned, appeared to be of interest especially since much is yet to be known about the behaviour of the Indian prawns and are therefore presented here

Huntington disease-like phenotype in a patient with ANO3 mutation

A 71-year-old previously well white British female developed progressive involuntary tongue movements over one year, resulting in eating difficulty and 10 kg weight loss. She had also noted involuntary perioral, facial and distal limb movements beginning 18 months earlier. These had progressively worsened. In the 3 years prior to presentation, she reported subjective memory decline, word finding difficulty and depressed mood, which improved with mirtazapine 30 mg once daily. She had no history of neuroleptic exposure. Her brother had died aged 40 years, following years of mental illness and substance abuse. She was estranged from her father, who was said to have had ‘behavioural problems’. Her paternal grandmother and maternal aunt had Parkinson's disease

Protein Expression, Characterization and Activity Comparisons of Wild Type and Mutant DUSP5 Proteins

Background The mitogen-activated protein kinases (MAPKs) pathway is critical for cellular signaling, and proteins such as phosphatases that regulate this pathway are important for normal tissue development. Based on our previous work on dual specificity phosphatase-5 (DUSP5), and its role in embryonic vascular development and disease, we hypothesized that mutations in DUSP5 will affect its function. Results In this study, we tested this hypothesis by generating full-length glutathione-S-transferase-tagged DUSP5 and serine 147 proline mutant (S147P) proteins from bacteria. Light scattering analysis, circular dichroism, enzymatic assays and molecular modeling approaches have been performed to extensively characterize the protein form and function. We demonstrate that both proteins are active and, interestingly, the S147P protein is hypoactive as compared to the DUSP5 WT protein in two distinct biochemical substrate assays. Furthermore, due to the novel positioning of the S147P mutation, we utilize computational modeling to reconstruct full-length DUSP5 and S147P to predict a possible mechanism for the reduced activity of S147P. Conclusion Taken together, this is the first evidence of the generation and characterization of an active, full-length, mutant DUSP5 protein which will facilitate future structure-function and drug development-based studies

Compressibility of CeMIn5Ce M In_5 and Ce2MIn8Ce_2 M In_8 (M = Rh, Ir and Co) Compounds

The lattice parameters of the tetragonal compounds Ce$M$In$_{5}$ and Ce$_{2}M$In$_{8}$($M=$Rh, Ir and Co) have been studied as a function of pressure up to 15 GPa using a diamond anvil cell under both hydrostatic and quasihydrostatic conditions at room temperature. The addition of $M$In$_{2}$ layers to the parent CeIn$_{3}$ compound is found to stiffen the lattice as the 2-layer systems (average of bulk modulus values $B_{0}$ is 70.4 GPa) have a larger $B_{0}$ than CeIn$_{3}$ (67 GPa), while the 1-layer systems with the are even stiffer (average of $B_{0}$ is 81.4 GPa). Estimating the hybridization using parameters from tight binding calculations shows that the dominant hybridization is $fp$ in nature between the Ce and In atoms. The values of $V_{pf}$ at the pressure where the superconducting transition temperature $T_{c}$ reaches a maximum is the same for all Ce$M$In$_{5}$ compounds. By plotting the maximum values of the superconducting transition temperature $T_{c}$ versus $c/a$ for the studied compounds and Pu-based superconductors, we find a universal $T_{c}$ versus $c/a$ behavior when these quantities are normalized appropriately. These results are consistent with magnetically mediated superconductivity.Comment: Updated version resubmitted to Phys. Rev.

Coexisting aegirine and magnesioriebeckite from Bababudan Hills, Mysore State

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Echocardiographic Parameters for Risk Prediction in Borderline Right Ventricle: Review with Special Emphasis on Pulmonary Atresia with Intact Ventricular Septum and Critical Pulmonary Stenosis

The aim of the present review is to highlight the strengths and limitations of echocardiographic parameters and scores employed to predict favorable outcome in complex congenital heart diseases (CHDs) with borderline right ventricle (RV), with a focus on pulmonary atresia with intact ventricular septum and critical pulmonary stenosis (PAIVS/CPS). A systematic search in the National Library of Medicine using Medical Subject Headings and free-text terms including echocardiography, CHD, and scores, was performed. The search was refined by adding keywords “PAIVS/CPS”, Ebstein’s anomaly, and unbalanced atrioventricular septal defect with left dominance. A total of 22 studies were selected for final analysis; 12 of them were focused on parameters to predict biventricular repair (BVR)/pulmonary blood flow augmentation in PAIVS/CPS. All of these studies presented numerical (the limited sample size) and methodological limitations (retrospective design, poor definition of inclusion/exclusion criteria, variability in the definition of outcomes, differences in adopted surgical and interventional strategies). There was heterogeneity in the echocardiographic parameters employed and cut-off values proposed, with difficultly in establishing which one should be recommended. Easy scores such as TV/MV (tricuspid/mitral valve) and RV/LV (right/left ventricle) ratios were proven to have a good prognostic accuracy; however, the data were very limited (only two studies with <40 subjects). In larger studies, RV end-diastolic area and a higher degree of tricuspid regurgitation were also proven as accurate predictors of successful BVR. These measures, however, may be either operator and/or load/pressure dependent. TV Z-scores have been proposed by several authors, but old and heterogenous nomograms sources have been employed, thus producing discordant results. In summary, we provide a review of the currently available echocardiographic parameters for risk prediction in CHDs with a diminutive RV that may serve as a guide for use in clinical practice