Biomimetic Deposition of Hydroxyapatite Layer on Titanium Alloys

Over the last decade, researchers have been concerned with improving metallic biomaterials with proper and suitable properties for the human body. Ti-based alloys are widely used in the medical field for their good mechanical properties, corrosion resistance and biocompatibility. The TiMoZrTa system (TMZT) evidenced adequate mechanical properties, was closer to the human bone, and had a good biocompatibility. In order to highlight the osseointegration of the implants, a layer of hydroxyapatite (HA) was deposited using a biomimetic method, which simulates the natural growth of the bone. The coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), micro indentation tests and contact angle. The data obtained show that the layer deposited on TiMoZrTa (TMZT) support is hydroxyapatite. Modifying the surface of titanium alloys represents a viable solution for increasing the osseointegration of materials used as implants. The studied coatings demonstrate a positive potential for use as dental and orthopedic implants.

Fly Ash Coated with Magnetic Materials: Improved Adsorbent for Cu (II) Removal from Wastewater

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins-Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.

New Materials Synthesized by Sulfuric Acid Attack Over Power Plant Fly Ash

In the current work, the preparation of a complex wastewater coagulant based on polymeric sulfates of aluminum/iron from fly ash is presented. The performance of the coagulation�flocculation process is mostly influenced by the coagulant type, which enhances the aggregation of particles and leads to formation of fast-settling flocs by charge neutralization or chain-bridging mechanisms. Within the preparation process, the reaction temperature was controlled at 80�C and 90�C for 4 h, the synthesized materials being characterized through different techniques (SEM, EDAX, FTIR, and XRD) and further used as coagulants for real wastewater treatment. As a novelty of this study, it can be mentioned that there were analyzed the possibilities of capitalization of Romanian fly ash collected from Iasi area and its transformation into complex based on aluminum - iron sulfates. Fly ash containing different concentrations of Fe2O3 and Al2O3 was successfully used in producing complex coagulants by reacting with 10% technical sulfuric acid solution. The produced complex coagulants contain both polymeric ferric sulfate (PFS) and polymeric aluminum sulfate (PAS) (demonstrated by complex characterization) and proved to be effective in wastewater treatment. These sustainable materials exhibited a good performance in coagulation�flocculation process (e.g. it was obtained a TSS removal efficiency of 84% at the coagulant dosage of 60 mg/L).

Modeling of Solid-Fluid non-catalytic Processes for Nickel Ion Removal

The aim of this study is modeling of the process of Ni(II) removal onto new materials synthesized by a facile coprecipitation method. The literature presents different surfactants intercalated on MgAl-LDH with applicability for nickel ions removal, but the researches on the use of this material ��as cast�� as adsorbent for Ni(II) ions are limited, it is reason to develop this study. The morphology, chemical composition, and the basic structure of the new material were analyzed by SEM, EDAX, BET, XRD and FT-IR. The kinetic modeling was performed using the pseudo-first-order, four-type linear pseudo-second-order, and intraparticle diffusion. The experimental data demonstrated that the adsorption process is very fast in the first 20 minutes and reach equilibrium after 50 min. The maximum adsorption capacities of the adsorbent are in the range of 36.5-68.18 mg/g, for the 200-500 mg/L initial solution concentration.

Bismuth-Doped Nanohydroxyapatite Coatings on Titanium Implants for Improved Radiopacity and Antimicrobial Activity

This study aims to present the possibility to obtain bismuth-doped nanohydroxyapatite coatings on the surface of the titanium implants by using a solution-derived process according to an established biomimetic methodology. The bioactivity of the titanium surface was increased by an alkali-thermal treatment. Then, under biomimetic conditions, the titanium surface was coated with a Bi-doped nanohydroxyapatite layer by using a modified supersaturated calcification solution (SCS) containing a bismuth salt. The apatite deposits were analyzed by scanning electron microscopy coupled with X-ray analysis (SEM-EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and digital X-rays radiography method. The results indicate that the Bi-doped nanohydroxyapatite coatings on titanium surface were produced. These coatings exhibit a good radiopacity, thus enhancing their applications in dental and orthopedic fields. Additionally, the Bi-doped nanohydroxyapatite coatings show significant antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria.

Experimental Study on the Influence of Zirconia Surface Preparation on Deposition of Hydroxyapatite

The present article is a preliminary study focused on the influence of zirconia surface on deposition of hydroxyapatite. The surface characteristics are very important for deposition of various materials. Most of the studies on zirconia are focused on dopped ZrO2 composites or on surface enhancement of these kind of materials. One of the most important property is the osseointegration which can be enhanced with various kind of treatments or deposition. Our preliminary study involved the mechanical grinding and respectively the chemical attack of the surface before the deposition. The results highlights that in order to obtained a better layer of hydroxyapatite the surface of the zirconia samples need to be prepared by chemical attack.

Histological and immunohistochemical evaluation of mandibular bone tissue regeneration

The purpose of the study was to perform an immunohistochemical and histological evaluation of samples taken from different bone regeneration procedures in atrophic human mandible. 30 patients (15 men and 15 women, age range of 35–60 years), non-smokers, with good general and oral health were recruited in this study and divided into three groups. The first group included patients who were treated with blood Concentration Growth Factors (bCGF), the second group included patients who were treated with a mixture of bCGF and autologous bone, while the third group of patients was treated with bCGF and tricalcium phosphate/hydroxyapatite (TCP-HA). Six months after the regenerative procedures, all patients undergone implant surgery, and a bone biopsy was carried out in the site of implant insertion. Each sample was histologically and immunohistochemically examined. Histological evaluation showed a complete bone formation for group II, partial ossification for group I, and moderate ossification for group III. Immunohistochemical analysis demonstrated a statistically significant difference between the three groups, and the best clinical result was obtained with a mixture of bCGF and autologous bone.

Studies on adsorption of oxytetracycline from aqueous solutions onto hydroxyapatite

The presence of antibiotics in the water and wastewater has raised problems due to potential impacts on the environment and consequently their removal is of great importance. For this reason, this article aims to perform a study on the possibility of oxytetracycline (OTC) adsorption from aqueous medium by using the hydroxyapatite (HA) nanopowders as adsorbent materials. The hydroxyapatite nanopowders were synthesized by wet precipitation method by using orthophosphoric acid and calcium hydroxide as raw materials and investigated by XRD, SEM-EDX, FTIR and BET methods. The uncalcined and calcined hydroxyapatite samples have hexagonal crystal structure with crystal sizes smaller than 100nm and a specific surface area of 316m²/g and 139m²/g, respectively. The adsorption behavior of oxytetracycline, a zwitterionic antibiotic, on nanohydroxyapatite was investigated as a function of pH, contact time, adsorbent dosage and drug concentration by means of batch adsorption experiments. High oxytetracycline removal rates of about 97.58% and 89.95% for the uncalcined and calcined nanohydroxyapatites, respectively, were obtained at pH8 and ambient temperature. The adsorption process of oxytetracycline onto nanohydroxyapatite samples was found to follow a pseudo-second order and intraparticle diffusion kinetic models. The maximum adsorption capacities of 291.32mg/g and 278.27mg/g for uncalcined and calcined nanohydroxyapatite samples, respectively, have been found. The adsorption mechanism of OTC on the hydroxyapatite surface at pH8 can be established via surface complexation. The obtained results are indicative of good hydroxyapatite adsorption ability towards oxytetracycline drug.

Erratum to: 36th International Symposium on Intensive Care and Emergency Medicine: Brussels, Belgium. 15-18 March 2016

[This corrects the article DOI: 10.1186/s13054-016-1208-6.].

Dental Implant Sites in Healthy versus Diabetic Subjects: A Two-Year Clinical and Bacteriological Assessment

The aim of this study was to analyze by Real-Time Polymerase Chain Reaction (PCR) possible differences in periimplant microbiota of patients without significant systemic diseases versus patients affected by non-insulin-dependent diabetes mellitus (NIDDM), both treated with dental implants with the same implant-abutment system. Patients suffering from NIDDM, and those with no history of major systemic diseases, treated with dental implants at the Prosthodontics Operative Unit of “Sapienza” University of Rome in the period February 2009 - March 2010 were considered. Clinical parameters as well as microbiological profile were evaluated for each implant site at 3, 6,12, and 24 month follow-up. Crevicular fluid was collected for microbial sampling and analyzed by Real-Time PCR in order to identify the possible presence of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, Tannerella forsythia, Treponema denticola, Fusobacterium nucleatum and Prevotella intermedia. Eight patients suffering from NIDDM and 22 with no history of major systemic diseases were included in the present investigation, each having received one to three dental implants. All the implants had been loaded 3 months after surgery, and the average follow-up after implant placement was 26.37±3.86. Clinical parameters showed no noticeable difference between the two groups, except for the Implant Stability Quotient (ISQ) that showed significantly lower values in NIDDM patients. A slightly higher amount of the considered pathogenic bacteria were retrieved in samples collected from patients with NIDDM (7.38×105) in comparison with those of healthy subjects (6.78×105), though the differences were below statistical significance. Within the limitations of the present study, a slight correlation was empirically detected between gene expression profiles of microbial populations and history of NIDDM, which however remained below the statistical significance. Further well-designed clinical studies may be useful to conclusively clarify the impact of subgingival microflora on the increased susceptibility of diabetic patients to periimplantitis.

Biochemical assessment of growth factors and circulation of blood components contained in the different fractions obtained by centrifugation of venous blood

The aim of this study was to evaluate a biochemical marker with different elements of a normal blood serum and centrifuged blood serum after a different rotation system. For this technique, we used five fractions of a blood Concentrated Growth Factors system (bCGF) and a particular device for the different rotation program. Blood samples were collected from 10 volunteers aged between 35 and 55 in the Operative Unit of the “Sapienza” University of Rome with only a fraction of different biochemical elements. Through an individual blood phase separator tube of venous blood, active factions of serum and 4 fractions of red buffy coat were taken. The biochemical markers with 14 elements were examined at times: P1-11 minutes, P2-12minutes, P3-15 minutes. Exclusively biological materials which are normally applied in the regeneration techniques for different defects and lesions were used with this technique. After specific rotation programs, a different result was obtained for each cycle: P1, P2, P3. In test tubes obtained by separated blood, we observed a higher concentration of proteins, ions, and other antigens compared to normal blood plasma. Examining the biochemical results of different elements, we observed an increase (P≤0,01). Since each person’s DNA is different, we could not have the same results in 5 fractions of blood concentration, we did, however, find a good increase in only a fraction of proteins, immunoglobulin and different ions. We obtained five fractions after centrifugation, and we had an increase in different biochemical elements compared to normal blood (P≤0,01) which is significant at different times. These biochemical elements were stimulated by different growth factors, which are used by the immune system, and they induced the formation of hard and soft tissues and good regeneration.

Investigation on the effect of collagen and vitamins on biomimetic hydroxyapatite coating formation on titanium surfaces

This study uses an in vitro experimental approach to investigate the roles of collagen and vitamins in regulating the deposition of hydroxyapatite layer on the pure titanium surface. Titanium implants were coated with a hydroxyapatite layer under biomimetic conditions by using a supersaturated calcification solution (SCS), modified by adding vitamins A and D3, and collagen. The hydroxyapatite deposits on titanium were investigated by means of scanning electron microscopy (SEM) coupled with X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results obtained have shown that hydroxyapatite coatings were produced in vitro under vitamins and collagen influence.

Functional magnetic resonance imaging contribution to language areas assessment in children with non-lesion focal epilepsy

Functional Magnetic Resonance Imaging (fMRI) is one of the newest areas of medical imaging which evaluates the activation of different zones in the brain during the acquisition of brain images by functional magnetic resonance. One of the applications of fMRI is the assessment of language area. In this article we summarize the most important data related to fMRI in the language assessment and we illustrate with a clinical case of a girl with symptomatic epilepsy secondary to a dual pathology of temporal lobe in the dominant cerebral hemisphere (tumour and dysplastic lesion), in which the use of this method helped at presurgical planning.

Oleate-LDH hybrids by the successive use of the clay structural "memory effect"

Oleate/LDH composites have been obtain by calcination-reconstruction procedures by the successive uses of the anionic clay memory effect. XRD and FTIR analysis were used to study the structural characteristics of the hybrid samples. The amount of oleate in the hybrid formulation of the clay matrix is highest after the second calcination-reconstruction cycle. After the fourth cycle the clay structure is not recovered anymore. This result points out to the "short" structural "memory" of the LDH-like clays. Textural features of the samples were studied by N2 adsorption at 77 K, SEM and TEM analyses. The oleate/LDH hybrids, obtained by the successive uses of the clay "memory", are defined by different crystallinity and micromorphological characteristics.

Zeolitical materials for microbiological filtrations

The paper presents some aspects about synthesis of new materials called zeolites which can be utilised as filters with wide application in clinical practice in microbiology and in pharmaceutical industry. The SAPO-5, SAPO-11 and SAPO-34 zeolites were synthesised by hydrothermal crystallisation and using different mixtures. The crystallisation was carried out in teflon-lined stainless steel autoclaves at 180-195 degrees C for 1-2 days, under autogenous pressure. Filtering properties of these materials are different because their pore diameters are different.

Diethylaminoethanol action in the arthritis with Freund adjuvant, in rats

The authors have studied the action of diethylaminoethanol on Freund adjuvant arthritis, induced in female Lewis rats. They worked on 3 groups, each one including 14 rats, weighing 110-130 g: group I = control; group II = rats injected intracutaneous with 0.1 ml Freund adjuvant; group III = rats injected with Freund adjuvant and treated with diethylaminoethanol i.m. (10 mg/kg body weight), and gel application (2.5%) on paws and tail, daily. During the experiment clinical observations and measurements were made and when the animals were killed, blood was sampled for haematological and immunological assays (CD4, CD8, CD25 T cells and NK cells, antinuclear autoantibody and immune complexes). While in all the rats from group II (without treatment) inflammatory processes developed at the level of the peripheral joints, in group III (diethylaminoethanol treated), these ones were present in only 64% of the rats and by much more reduced forms, followed by a short period of involution. The paw volume, measured with an electronic plethysmometer, was more reduced in the treated rats (7.1-14.2%) than in the non treated ones (27.7-29.3%). The haematologic examination showed an increased number of neutrophiles in both groups with FA injecting. The immunological investigations revealed: a decrease of CD4 cells and an increase of CD8 T cells and NK cells in both groups, a much more decreased level (13.2%) of circulatory immune complexes in treated rats, as compared to the non-treated ones (71.7%). No differences were found regarding the CD25 cells and antinuclear antibodies. The histo-pathological examination showed that the intensity and the extension area of the joint lesions (granulation tissue with fibrous change, cartilage invasion and dilaceration, bone atrophy) were much more reduced in the treated rats. The authors put forward the hypothesis that these effects might be due to diethylaminoethanol antiinflammatory properties.