Studying the Peculiar Velocity Bulk Flow in a Sparse Survey of Type-Ia SNe

Studies of the peculiar velocity bulk flow based on different tools and datasets have been consistent so far in their estimation of the direction of the flow, which also happens to lie in close proximity to several features identified in the cosmic microwave background, providing motivation to use new compilations of type-Ia supernovae measurements to pinpoint it with better accuracy and up to higher redshift. Unfortunately, the peculiar velocity field estimated from the most recent Union2.1 compilation suffers from large individual errors, poor sky coverage and low redshift-volume density. We show that as a result, any naive attempt to calculate the best-fit bulk flow and its significance will be severely biased. Instead, we introduce an iterative method which calculates the amplitude and the scatter of the direction of the best-fit bulk flow as deviants are successively removed and take into account the sparsity of the data when estimating the significance of the result. Using 200 supernovae up to a redshift of z=0.2, we find that while the amplitude of the bulk flow is marginally consistent with the value expected in a LCDM universe given the large bias, the scatter of the direction is significantly low (at >= 99.5 C.L.) when compared to random simulations, supporting the quest for a cosmological origin.Comment: 7 pages, 6 figures; typos fixed; clarifications made; important references adde

Nanoceramics in biomedical applications

An improved understanding of the interactions at the anoscale level between the bioceramics in medical implants and the hard or soft tissues in the human body could contribute significantly to the design of new-generation prostheses and postoperative patient management strategies. Overall the benefits of advanced ceramic materials in biomedical applications have been universally accepted, specifically in terms of their strength, biocompatibility, hydrophilicity and wear resistance in articulating joints. The continuous development of new-generation impalnts untilising nanocoatings with novel nanosensors and devices is leaf=ding to better compatibility with human tissue and improved well-being and longevity for patients. This article gives a short oevrview odf bioceramics and reexamines key issues of concern for processing and applying nanosensors as biomaterials

Kinetics and the Theoretical Aspects of Drug Release from PLA/HAp Thin Films

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.The theory of dissolution kinetics of gentamicin from polylactic acid-hydroxyapatite thin film composites is spotlighted with the combination of diffusion and polymer degradation modeling. The use of various mathematical models, characterizing diffusion, dissolution or/and erosion prevalence as well as a mix of dissolution-diffusion rate processes were employed in order to compare theory with experimental data. A number of factors influence the release kinetics of gentamicin from medical drug release systems and devices. It is difficult to have a single mathematical model that takes all these factors into account. It is shown that the degradation of the polymer matrix plays the biggest role in the release kinetics of polymer-ceramics thin film composites. It was also observed that multistage drug release form these devices depends also on the degradation kinetics of the polymer matrix. The effect of pH and device sizes were not studied but could also be of interest in future studies

On the Stringy Hartle-Hawking State

We argue that non-perturbative $\alpha'$ stringy effects render the Hartle-Hawking state associated with the $SL(2)/U(1)$ eternal black hole singular at the horizon. We discuss implications of this observation on firewalls in string theory

Innovative bioceramics

Overall, the benefits of advanced ceramic materials in biomedical applications have been universally appreciated, specifically, in terms of their strength, biocompatibility and wear resistance. However, the amount of supporting data is not large and the continuous development of new methods is pertinent for better understanding of the microstructure-properties relationship and, in general, for obtaining new directives for their further improvement. This paper gives an overview of some of the more innovative applications of bioceramics in medicine. © Institute of Materials Engineering Australasia Ltd - Materials Forum Volume 27 - Published 2004

Marine skeletons: Towards hard tissue repair and regeneration

© 2018 by the authors. Musculoskeletal disorders in the elderly have significantly increased due to the increase in an ageing population. The treatment of these diseases necessitates surgical procedures, including total joint replacements such as hip and knee joints. Over the years a number of treatment options have been specifically established which are either permanent or use temporary natural materials such as marine skeletons that possess unique architectural structure and chemical composition for the repair and regeneration of bone tissue. This review paper will give an overview of presently used materials and marine structures for hard tissue repair and regeneration, drugs of marine origin and other marine products which show potential for musculoskeletal treatment

Functionalisation of Ti6Al4V and hydroxyapatite surfaces with combined peptides based on KKLPDA and EEEEEEEE peptides

Surface modifications are usually performed on titanium alloys to improve osteo-integration and surface bioactivity. Modifications such as alkaline and acid etching, or coating with bioactive materials such as hydroxyapatite, have previously been demonstrated. The aim of this work is to develop a peptide with combined titanium oxide and hydroxyapatite binders in order to achieve a biomimetic hydroxyapatite coating on titanium surfaces. The technology would also be applicable for the functionalisation of titanium and hydroxyapatite surfaces for selective protein adsorption, conjugation of antimicrobial peptides, and adsorption of specialised drugs for drug delivery. In this work, functionalisation of Ti6Al4V and hydroxyapatite surfaces was achieved using combined titanium-hydroxyapatite (Ti-Hap) peptides based on titanium binder (RKLPDA) and hydroxyapatite binder (EEEEEEEE) peptides. Homogeneous peptide coatings on Ti6Al4V surfaces were obtained after surface chemical treatments with a 30 wt % aqueous solution of H2O2 for 24 and 48 hours. The treated titanium surfaces presented an average roughness of Sa=197 nm (24 h) and Sa=128 nm (48 h); an untreated mirror polished sample exhibited an Sa of 13 nm. The advancing water contact angle of the titanium oxide layer after 1 hour of exposure to 30 wt % aqueous solution of H2O2 was around 65°, decreasing gradually with time until it reached 35° after a 48 hour exposure, suggesting that the surface hydrophilicity increased over etching time. The presence of a lysine (L) amino acid in the sequence of the titanium binder resulted in fluorescence intensity roughly 16 % higher compared with the arginine (R) amino acid analogue and therefore the lysine containing titanium binder was used in this work. The Ti-Hap peptide KKLPDAEEEEEEEE (Ti-Hap1) was not adsorbed by the treated Ti6Al4V surfaces and therefore was modified. The modifications involved the inclusion of a glycine spacer between the binding terminals (Ti-Hap2) and the addition of a second titanium binder (KKLPDA) (Ti-Hap3 and Ti-Hap4). The Ti-Hap peptide aptamer which exhibited the strongest intensity after the titanium dip coating was KKLPDAKKLPDAEEEEEEEE (Ti-Hap4). On the other hand, hydroxyapatite surfaces, exhibiting an average roughness of Sa=1.42 µm, showed a higher fluorescence for all peptides compared with titanium surfaces

The effect of titanium (Ti) and titanium 500 (ti 500) implantation on the activation of rat macrophage subgroups

© 2019, Editorial Ciencias Medicas. All rights reserved. Introduction: Nowadays it is necessary to make new researches in order to solve the problems related to the prolongation of life and related health problems, especially fractures and spinal degeneration. The biocompatibility, mechanical compatibility, morphological compatibility and osseointegration properties of the implant material are very important. In order to prevent unwanted side effects in the use of biomaterials, new strategies need to be developed. Implants, where they will be implanted and their functions will vary according to the characteristics of the material used. The most commonly used metallic materials are 316L stainless steel, Co-Cr alloys and Ti alloys. Objective: To demostrate the effect of Titanium and Titanium 500 on activation of macropages Material and Methods: Our research was performed in the Laboratory of Cytokines and Receptors in the Department of Physiology of Cerrahpasa Medical Faculty, Istanbul University-Cerrahpasa. Our research has been approved by the Animal Experiments Local Ethics Committee of Bezmialem Vakif University (Approval Number:2017/218). In order to control the rejection of the patient with specific inflammation caused by titanium implantation, we analyzed the first triggered cells of the innate immun system, especially macrophages and sub-groups (M1, M2a, M2b, M2c), by implanting Titanium and Titanium 500 into the spinal region in Wistar albino male rats. According to the Power Analysis statistic program, 3 different groups of Wistar albino species male rats with a weight of 250 - 300 grams and 10-12 weeks of age were formed. Group I (n: 8, Sham group (Control)), Group II (n: 8, Titanium alloy), Group III (n: 8, Titanium 500). No implant was used in Group I (sham group). Only surgical stress was applied to the rats and they were closed again. In Group II and Group III, the rods were placed on the lamina. Peripheral blood samples were collected on the 1st, 3rd, 5th and 7th days following the implantation phase. M1 macrophages (CCL3, CCL4, CXCL9, IL-23), M2a macrophages (CD163, CD206), M2b macrophages (CCL1), M2c macrophage (SLAM) markers were examined by ELISA (Enzyme-Linked ImmunoSorbent Assay) method. Groups were compared with one-way analysis of variance (ANOVA). For the paired comparison of significant variables, a statistically significant difference (HSD) test was used for Tukey's homogeneous variance variables. Statistical significance was set at p < 0.05. Results and Conclusions: We believe that our analysis results will be helpful in the control, prevention, immunological and therapeutic methods of the reactions (inflammation, rejection, etc.) that may occur in patients who are implanted with Titanium (Ti) and Titanium 500 (Ti 500) implants (spinal, orthopedic, dental etc.)