Zn doped CaP coatings used for controlling the degradation rate of MgCa1 alloy: In vitro anticorrosive properties, sterilization and bacteria/cell-material interactions.

The purpose of this study was to investigate the effect of Zn doped CaP coatings prepared by micro-arc oxidation method, as a possible approach to control MgCa1 alloy degradation. All the prepared coatings comprised a calcium deficient CaP phase. The control in this evaluation was performed with undoped CaP coating in SBF solution at body temperature (37 ± 0.5°C). The investigation involved determination of microchemical, mechanical, morphological, properties along with anticorrosive, cytocompatibility and antibacterial efficacy. The effect of sterilization process on the properties of the surfaces was also investigated. The results showed that the addition of Zn into CaP increased the corrosion resistance of MgCa1 alloy. Moreover, the adhesion strength of the coatings to MgCa1 alloy was enhanced by Zn addition. In cytotoxicity testing of the samples, extracts of the samples in MEM were incubated with L929 cells and malformation, degeneration and lysis of the cells were examined microscopically after 72 h. The results showed that all samples were cytocompatible. The degradation of MgCa1 alloy in the simulated body fluids (SBF) or DMEM was decreased by coating with CaP. Moreover, the degradation rate of CaP was further decreased by adding a small amount of Zn into the CaP matrix. The samples having CaP coatings and Zn doped CaP coating demonstrated antibacterial efficacy against E.coli. As a result, coating of magnesium alloy with Zn-doped CaP decreased the degradation rate, increased the corrosion resistance, cytocompatibility and the antibacterial effects of the alloys.

Physical Fundamentals of Biomaterials Surface Electrical Functionalization.

This article is focusing on electrical functionalization of biomaterial's surface to enhance its biocompatibility. It is an overview of previously unpublished results from a series of experiments concerning the effects surface electrical functionalization can have on biological systems. Saccharomyces cerevisiae cells were used for biological experiments. The hydroxyapatite (HAp) specimens were used to investigate influence of structural point defects on the surface electrical charge. Threshold photoelectron emission spectroscopy was used to measure the electron work function of HAp and biologic samples. The density functional theory and its different approximations were used for the calculation of HAp structures with defects. It was shown that the electrical charge deposition on the semiconductor or dielectric substrate can be delivered because of production of the point defects in HAp structure. The spatial arrangements of various atoms of the HAp lattice, i.e., PO4 and OH groups, oxygen vacancies, interstitial H atoms, etc., give the instruments to deposit the electrical charge on the substrate. Immobilization of the microorganisms can be achieved on the even surface of the substrate, characterized with a couple of nanometer roughness. This cells attachment can be controlled because of the surface electrical functionalization (deposition of the electrical charge). A protein layer as a shield for the accumulated surface charge was considered, and it was shown that the protein layer having a thickness below 1 µm is not crucial to shield the electrical charge deposited on the substrate surface. Moreover, the influence of surface charge on the attachment of microorganisms, when the surface roughness is excluded, and the influence of controlled surface roughness on the attachment of microorganisms, when surface charge is constant, were also considered.

High-Dose Vitamin D Supplementation Improves Microcirculation and Reduces Inflammation in Diabetic Neuropathy Patients.

We assessed the effect of different doses of vitamin D supplementation on microcirculation, signs and symptoms of peripheral neuropathy and inflammatory markers in patients with type 2 diabetes (T2DM). Sixty-seven patients with T2DM and peripheral neuropathy (34 females) were randomized into two treatment groups: Cholecalciferol 5000 IU and 40,000 IU once/week orally for 24 weeks. Severity of neuropathy (NSS, NDS scores, visual analogue scale), cutaneous microcirculation (MC) parameters and inflammatory markers (ILs, CRP, TNFα) were assessed before and after treatment. Vitamin D deficiency/insufficiency was detected in 78% of the 62 completed subjects. Following treatment with cholecalciferol 40,000 IU/week, a significant decrease in neuropathy severity (NSS, p = 0.001; NDS, p = 0.001; VAS, p = 0.001) and improvement of cutaneous MC were observed (p < 0.05). Also, we found a decrease in IL-6 level (2.5 pg/mL vs. 0.6 pg/mL, p < 0.001) and an increase in IL-10 level (2.5 pg/mL vs. 4.5 pg/mL, p < 0.001) after 24 weeks of vitamin D supplementation in this group. No changes were detected in the cholecalciferol 5000 IU/week group. High-dose cholecalciferol supplementation of 40,000 IU/week for 24 weeks was associated with improvement in clinical manifestation, cutaneous microcirculation and inflammatory markers in patients with T2DM and peripheral neuropathy.

Relationship Between Vitamin D Status and Vitamin D Receptor Gene Polymorphisms With Markers of Metabolic Syndrome Among Adults.

Introduction: Recent studies have demonstrated that vitamin D deficiency contributes to the development of metabolic disorders, including obesity and type 2 diabetes mellitus (T2DM). Several vitamin D receptor (VDR) gene polymorphisms had been described to play a role in these conditions since vitamin D receptors were found in many tissues. The aim of this study was to assess the relationship between vitamin D status and VDR gene polymorphisms with metabolic syndrome (MS) parameters in Russian middle-aged women. Materials and Methods: A total of 697 women aged between 30 to 55 years were included in this cross-sectional study. Serum 25-hydroxyvitamin D (25(OH)D) level and four VDR gene polymorphisms rs1544410 (BsmI), rs7975232 (ApaI), rs731236 (TaqI), and rs2228570 (FokI) were measured. We applied the International Diabetes Federation (IDF) criteria to identify subjects with MS. Results: 9.3% of subjects had normal vitamin D level, while 90.7% were insufficient or deficient. Abdominal obesity (AO) was seen in 75.5%, impaired glucose tolerance (IGT) or T2DM was observed in 33.3%, reduced high-density lipoprotein cholesterol (HDL-C) level in 32.2% and hypertriglyceridemia in 23.4%. Serum 25(OH)D level in women with or without MS did not differ (48.6 ± 1.8 and 51.1 ± 1.5 nmol/l, p > 0.05). Subjects with vitamin D deficiency showed an increased risk of AO [CI 95% 2.23; 1.15-4.30] and low HDL-C [CI95% 2.60; 1.04-6.49] compared to subjects with normal 25(OH)D level. IGT and T2DM risk was increased only when 25(OH)D concentration was less than 39.0 nmol/l [CI 95% 7.17; 2.99-17.7], but risk of MS did not differ in normal vitamin D status subjects and insufficient/deficient ones (p > 0.05). T allele carriers (A) of rs7975232 had higher total cholesterol and low-density lipoprotein cholesterol levels compared with the GG (aa) genotypes. Similarly, GG (BB) genotype carriers of rs1544410 had higher triglyceride levels than subjects with A (b) allele carriers. However VDR gene polymorphisms did not seem to be associated with an increased risk of MS. Conclusions: Vitamin D deficiency, rs7975232, and rs1544410 VDR gene variants are associated with MS parameters in Russian middle-aged women.

HAP nanoparticle and substrate surface electrical potential towards bone cells adhesion: Recent results review.

Nanostructured hydroxyapatite (HAP) and its nanoparticles are widely used for implantation into the human organism. The biocompatibility of the implants depends very much on the interaction between the implant and the cells regenerating tissue to be connected to the implant. An implant surface electrical charged density plays an important role in these processes. Possible instruments managing the surface electrical potential of HAP are in the focus of this paper. Both theoretical and experimental results evidence that: - the surface electrical charge density of the nanoparticle depends on its size and shape; - the electrical charge density of HAP could be engineered by contact less technique because of deposition of the electrical charge from the external radiation source, surface couples reconstruction.

ANALYSIS OF TRENDS IN LIFE EXPECTANCIES AND PER CAPITA GROSS DOMESTIC PRODUCT AS WELL AS PHARMACEUTICAL AND NON-PHARMACEUTICAL HEALTHCARE EXPENDITURES.

Life expectancy is a common measure of population health. Macro-perspective based on aggregated data makes it possible to approximate the impact of different levels of pharmaceutical expenditure on general population health status and is often used in cross-country comparisons. The aim of the study was to determine whether there are long-run relations between life expectancy, total healthcare expenditures, and pharmaceutical expenditures in OECD countries. Common trends in per capita gross domestic products (GDPs) (excluding healthcare expenditures), per capita healthcare expenditures (excluding pharmaceutical expenditures), per capita pharmaceutical expenditures, and life expectancies of women and men aged 60 and 65 were analyzed across OECD countries. Short-term effect of pharmaceutical expenditure onto life expectancy was also estimated by regressing the deviations of life expectancies from their long-term trends onto the deviations of pharmaceutical and non-pharmaceutical health expenditures, as well as GDP from their trends. The dataset was created on the basis of OECD Health Data for 34 countries and the years 1991-2010. Life expectancy variables were used as proxies for the health outcomes, whereas the pharmaceutical and healthcare expenditures represented drug and healthcare consumption, respectively. In general, both expenditures and life expectancies tended to increase in all of the analyzed countries; however, the growth rates differed across the countries. The analysis of common trends indicated the existence of common long-term trends in life expectancies and per capita GDP as well as pharmaceutical and non-pharmaceutical healthcare expenditures. However, there was no evidence that pharmaceutical expenditures provided additional information about the long-term trends in life expectancies beyond that contained in the GDP series. The analysis based on the deviations of variables from their long-term trends allowed concluding that pharmaceutical expenditures significantly influenced life expectancies in the short run. Non-pharmaceutical healthcare expenditures were found to be significant in one out of four models (for life expectancy of women aged 65), while GDPs were found to be insignificant in all four models. The results of the study indicate that there are common long-term trends in life expectancies and per capita GDP as well as pharmaceutical and non-pharmaceutical healthcare expenditures. The available data did not reveal any cause- effect relationship. Other factors, for which the systematic data were not available, may have determined the increase in life expectancy in OECD countries. Significant positive short-term relations between pharmaceutical expenditures and life expectancies in OECD countries were found. The significant short-term effect of pharmaceutical expenditures onto life expectancy means that an increase of pharmaceutical expenditures above long-term trends would lead to a temporary increase in life expectancy above its corresponding long-term trend. However, this effect would not persist as pharmaceutical expenditures and life expectancy would converge to levels determined by the long-term trends.

Effects of DRG-based hospital payment in Poland on treatment of patients with stroke.

A prospective payment system based on Diagnosis Related Groups (DRGs) presents strong financial incentives to healthcare providers. These incentives may have intended as well as unintended consequences for the healthcare system. In this paper we use administrative data on stroke admissions to Polish hospitals in order to demonstrate the response of hospitals to the incentives embedded in the design of stroke-related groups in Poland. The design was intended to motivate hospitals for the development of specialized stroke units by paying significantly higher tariffs for treatment of patients in these units. As a result, an extensive network of stroke units has emerged. However, as it is shown in the paper, there is no evidence that outcomes in hospitals with stroke units are significantly different from outcomes in hospitals without stroke units. It is also demonstrated that the reliance on the length of stay as a major grouping variable provides incentives for regrouping patients into more expensive groups by extending their length of stay in stroke units. The results of the study are limited by the incompleteness of the casemix data. There is a need to develop information and audit systems which would further inform a revision of the DRG system aimed to reduce the risk of regrouping and up-coding.

Molecular modeling of the piezoelectric effect in the ferroelectric polymer poly(vinylidene fluoride) (PVDF).

In this work, computational molecular modeling and exploration was applied to study the nature of the negative piezoelectric effect in the ferroelectric polymer polyvinylidene fluoride (PVDF), and the results confirmed by actual nanoscale measurements. First principle calculations were employed, using various quantum-chemical methods (QM), including semi-empirical (PM3) and various density functional theory (DFT) approaches, and in addition combined with molecular mechanics (MM) methods in complex joint approaches (QM/MM). Both PVDF molecular chains and a unit cell of crystalline ß-phase PVDF were modeled. This computational molecular exploration clearly shows that the nature of the so-called negative piezo-electric effect in the ferroelectric PVDF polymer has a self-consistent quantum nature, and is related to the redistribution of the electron molecular orbitals (wave functions), leading to the shifting of atomic nuclei and reorganization of all total charges to the new, energetically optimal positions, under an applied electrical field. Molecular modeling and first principles calculations show that the piezoelectric coefficient d 33 has a negative sign, and its average values lies in the range of d 33 ~ -16.6 to -19.2 pC/N (or pm/V) (for dielectric permittivity ε = 5) and in the range of d 33 ~ -33.5 to -38.5 pC/N (or pm/V) (for ε = 10), corresponding to known data, and allowing us to explain the reasons for the negative sign of the piezo-response. We found that when a field is applied perpendicular to the PVDF chain length, as polarization increases the chain also stretches, increasing its length and reducing its height. For computed value of ε ~ 5 we obtained a value of d31 ~ +15.5 pC/N with a positive sign. This computational study is corroborated by measured nanoscale data obtained by atomic force and piezo-response force microscopy (AFM/PFM). This study could be useful as a basis for further insights into other organic and molecular ferroelectrics.