Enhanced antimicrobial properties and bioactivity of 3D-printed titanium scaffolds by multilayer bioceramic coating for large bone defects.

The restoration of large bone defects caused by trauma, tumor resection, or infection is a major clinical problem in orthopedics and dentistry because postoperative infections, corrosion, and limited osteointegration of metal implants can lead to loosening of the implant. The aim of this study was to improve the surface properties of a 3D-printed (electron beam melting) Ti6Al4V-based macroporous scaffold by multilayer coating with bioactive silicate glasses (BAGs) and hydroxyapatite doped with a silver (AgHAP) or AgHAP additionally sonochemically modified with ZnO (ZnO-AgHAP). The coated scaffolds AgHAP_BAGs_Ti and ZnO-AgHAP_BAGs_Ti enhanced cytocompatibility in L929 and MRC5 cell lines and expressed bioactivity in simulated body fluid. A lower release of vanadium ions in coated samples compared to bare Ti scaffold indicates decreased dissolution of Ti alloy in coated samples. The coated samples reduced growth ofEscherichia coliandStaphylococcus aureusfor 4-6 orders of magnitude. Therefore, the 3D-printed Ti-based scaffolds coated with BAGs and (ZnO-)AgHAP have great potential for application as a multifunctional implant with antibacterial properties for the restoration of defects in load-bearing bones.

Hybrid material based on subgleba of mosaic puffball mushroom (Handkea utriformis) as an adsorbent for heavy metal removal from aqueous solutions.

The alkali treated subglebal tissue of the mosaic puffball (Handkea utriformis) (Sa) and Sa modified with hydroxyapatite (Sa-HAp), obtained by successive ionic layer adsorption and reaction (SILAR) method, were used for the removal of Pb2+, Cd2+ and Ni2+ from aqueous solution. The materials were characterized by FT-IR, Raman, SEM and EDS analysis and by determination of pHPZC. The adsorption performances of Sa and Sa-HAp were assessed in batch experiments at different pH, contact times, temperatures and mass of the adsorbent. Different models of adsorption isotherms were used, and the best fit was obtained with the Langmuir model. Maximum adsorption capacities of Sa towards Pb2+, Cd2+ and Ni2+ were 44.82, 15.54 and 17.21 mg g-1, while for Sa-HAp were 79.55, 52.59 and 45.01 mg g-1, respectively. Kinetic data were well fitted by a pseudo second-order model, while thermodynamic studies disclose spontaneous and endothermic adsorption process. The Sa-Hap was successfully regenerated with 1 M NaCl and after the fifth desorption cycle and 10 h achieved 82.9, 69.7 and 60.4 %, while for 0.5 M NaCl + 0.5 M NaOH and 1 h was 78.3, 64.1, 57.5 % of desorbed Pb2+, Cd2+ and Ni2+, respectively. The competitive study and results from a column system confirmed good applicability of Sa-HAp adsorbent.

First report on the nationwide prevalence of paediatric type 1 diabetes in Serbia and temporal trends of diabetes ketoacidosis at diagnosis-a multicentre study.

We aimed to collect data on all paediatric patients who were diagnosed with type 1 diabetes mellitus (T1DM) between the years 2000 and 2019 in Serbia and estimate for the first time its prevalence. Also, the trends of diabetes ketoacidosis (DKA) occurrence at the time of diagnosis are monitored. We collected and retrospectively analysed the data of patients <19 years with newly diagnosed T1DM. T1DM was diagnosed in 3134 patients (53.2% male). Total number of youth <19 years with T1DM was 1735 with prevalence of 135.25/100000 at the end of study period. T1DM was diagnosed most frequently between the ages of 5 and 11 years (42.1%). At the time of diagnosis, 35.7% presented in DKA. The incidence and severity of DKA were more significant at the youngest age (p<0.001). There were significant annual percentage increase (2.2%) in the number of new cases of DKA (p=0.007). Conclusion: This first report of nationwide prevalence of T1DM in youth shows that Serbia is among countries with high prevalence of T1DM in youth. System changes are needed in order to provide better quality of health care to these patients.

Highly Active Rutile TiO2 Nanocrystalline Photocatalysts.

The controllable synthesis of rutile TiO2 single crystal particles with the preferential orientation of {111} facets still remains a scientific and technological challenge. Here, we developed a facile route for fabrication of rutile TiO2 nanorod crystals (RTiO2NRs) having high ratios of oxidative {111} to reductive {110} surfaces. RTiO2NRs were synthesized using a peroxo-titanium complex (PTC) approach, which was controlled by changing the Ti/H2O2 ratio. The thus obtained RTiO2NRs revealed a high tendency to agglomerate through orientation-dependent attachment along the {110} facets. This resulted in an increased {111}/{110} surface ratio and led to a markedly improved photocatalytic activity of RTiO2NR aggregates. The reported findings illustrate the rich potential of the herein proposed facile and energy-efficient synthesis of nanostructured rutile TiO2-based photocatalysts.

Dissimilar sintered calcium phosphate dental inserts as dentine substitutes: Shear bond strength to restorative materials.

The application of sintered calcium phosphate dental inserts in the central part of tooth cavities can reduce amount of embedded dental composite and polymerization shrinkage of final dental fillings. The aim of this study was to analyze comparatively physico-chemical and mechanical properties of dental inserts and shear bond strength (SBS) between three dissimilar hydroxyapatite-based dental inserts and different restorative materials, after application of different clinical protocols. Starting from two different hydroxyapatite nano powders and nanostructured stabilized zirconia (YSZ), monophasic two-step sintered dense HAp inserts (TSSHAp), biphasic single-step sintered controlled porous inserts (HAp/TCp), and single-step sintered reinforced HAp/YSZ inserts were processed and characterized. Obvious differences in the microstructure of inserts surface were visualized after etching with 37% phosphoric acid. Fracture toughness of sintered inserts was ranged between 1.01 and 1.85 MPam1/2 (maximum value in the case of HAp/YSZ), while hardness values were in the range of 3.71-5.22 GPa (maximum value in the case of TSSHAp). Acid etching before application improved SBS between inserts and Maxcem compared to direct cement application. TSSHAp and HAP/TCp inserts showed comparable and relatively high SBS values, certainly higher compared to HAp/YSZ inserts. Slightly higher SBS values were measured in the case of TSSHAp insert group, and the highest mean SBS value of 18.51 MPa was determined between TSSHAp inserts and Filtek Z250_SBU following the "self-etch" protocol.

Mesoporous Silica and Organosilica Nanomaterials as UV-Blocking Agents.

Mesoporous silica nanoparticles (MSN) and periodic mesoporous organosilica nanoparticles containing bridging benzene (PMOBTB) and ethane (PMOBTE) moieties are synthesized, characterized, and evaluated for application in skin protection from UVA/UVB sun irradiation. Furthermore, the influence of surface functionalization with chelating 3-(2-aminoethylamino)propylsilane and Zn2+ ions on the UV-blocking ability of MSN is evaluated, along with the photostability and capability of the synthesized nanomaterials to carry avobenzone, a known UV-absorbing agent. The obtained results reveal promising characteristics of MSN and PMO materials with regard to their potential for sunscreen applications, which could be beneficial in terms of alleviating concerns about health and environmental hazards of sunscreen ingredients.

Enhanced absorption of TiO2 nanotubes by N-doping and CdS quantum dots sensitization: insight into the structure.

Anodization of titanium film sputtered on fluorine doped tin oxide (FTO) glass was performed to obtain highly ordered ∼2 µm long and ∼60 nm wide TiO2 nanotubes. The titania films were annealed in ammonia atmosphere to enable the doping with N. The annealing did not affect the nanotubular morphology and the porosity remained open which is a very important requirement for further deposition of CdS quantum dots. The analysis done by transmission electron microscopy (TEM) has shown that the N-doped nanotubes have a smaller interplanar distance as compared to the undoped ones, whose interplanar distance corresponded to anatase phase. This difference was attributed to the N doping and the Sn migration from the substrate, as demonstrated by energy dispersive spectroscopy (EDS) combined with electron energy loss spectroscopy (EELS). The near edge X-ray absorption fine structure (NEXAFS) analysis clearly demonstrated that also the doped TiO2 film has anatase phase. Regarding the chemical composition of the studied samples, the X-ray photoelectron spectroscopy (XPS) and synchrotron radiation photoelectron spectroscopy (SRPES) analyses have shown that N is incorporated both interstitially and substitutionally in the TiO2 lattice, with a decreased contribution of the interstitial after ionic sputtering. The shift of the valence band maximum (VBM) position for the doped TiO2 vs. the undoped TiO2 proved the narrowing of the band gap. The CdS/TiO2 films show bigger VBM shifting that can be attributed to CdS deposit. Comparing the absorption spectra of the bare undoped and doped TiO2 samples, it was noticed that the doping causes a red shift from 397 to 465 nm. Furthermore, the CdS deposition additionally enhances the absorption in the visible range (575 nm for undoped TiO2/CdS and 560 nm for doped TiO2/CdS films).

Nanoscale zerovalent iron (nZVI) supported by natural and acid-activated sepiolites: the effect of the nZVI/support ratio on the composite properties and Cd2+ adsorption.

Natural (SEP) and partially acid-activated (AAS) sepiolites were used to prepare composites with nanoscale zerovalent iron (nZVI) at different (SEP or AAS)/nZVI ratios in order to achieve the best nZVI dispersibility and the highest adsorption capacity for Cd2+. Despite the higher surface area and pore volume of AAS, better nZVI dispersibility was achieved by using SEP as the support. On the other hand, a lower oxidation degree was achieved during the synthesis using AAS. X-ray photoelectron spectroscopy (XPS) analysis of the composite with the best nZVI dispersibility, before and after Cd2+ adsorption, confirmed that the surface of the nZVI was composed of oxidized iron species. Metallic iron was not present on the surface, but it was detected in the subsurface region after sputtering. The content of zerovalent iron decreased after Cd2+ adsorption as a result of iron oxidation during Cd2+ adsorption. The XPS depth profile showed that cadmium was present not only at the surface of the composite but also in the subsurface region. The adsorption isotherms for Cd2+ confirmed that the presence of SEP and AAS decreased the agglomeration of the nZVI particles in comparison to the pure nZVI, which provided a higher adsorption capacity. The results showed that the prevention of both aggregation and oxidation during the synthesis was necessary for obtaining an SEP/AAS-nZVI composite with a high adsorption capacity, but oxidation during adsorption was beneficial for Cd2+ removal. The formation of strong bonds between Cd2+ and the adsorbents sites of different energy until monolayer formation was proposed according to modeling of the adsorption isotherms.

Distribution and mobility of heavy elements in floodplain agricultural soils along the Ibar River (Southern Serbia and Northern Kosovo). Chemometric investigation of pollutant sources and ecological risk assessment.

This work investigates the influence of a high-magnitude flood event on heavy elements (HEs) pollution and mobility in the agricultural soils along Ibar River in Southern Serbia and Northern Kosovo. The study area was one of the most important Pb/Zn industrial regions in Europe. Soil samples (n = 50) collected before and after the floods in May 2014 were subjected to the sequential extraction procedure proposed by the Community Bureau of Reference (BCR). The results indicated that the floods significantly increased not only the pseudo total concentrations of HEs in the soil but also their mobile and potentially bioavailable amounts. Moreover, higher concentrations (both pseudo total and potentially bioavailable) were found in the agricultural soils closer to the industrial hotspots. Principal component analysis and hierarchical cluster analysis successfully grouped the analyzed elements according to their anthropogenic or natural origin. The floods significantly increased the potential ecological risk of HEs associated with Pb/Zn industrial activities in the study area. The potential ecological risk of Cd after the floods was highest and should be of special concern.

The effect of grain size on the biocompatibility, cell-materials interface, and mechanical properties of microwave-sintered bioceramics.

The effect of decreasing the grain size on the biocompatibility, cell-material interface, and mechanical properties of microwave-sintered monophase hydroxyapatite bioceramics was investigated in this study. A nanosized stoichiometric hydroxyapatite powder was isostatically pressed at high pressure and sintered in a microwave furnace in order to obtain fine grained dense bioceramics. The samples sintered at 1200°C, with a density near the theoretical one, were composed of micron-sized grains, while the grain size decreased to 130 nm on decreasing the sintering temperature to 900°C. This decrease in the grain size certainly led to increases in the fracture toughness by much as 54%. An in vitro investigation of biocompatibility with L929 and human MRC-5 fibroblast cells showed noncytotoxic effects for both types of bioceramics, while the relative cell proliferation rate, cell attachment and metabolic activity of the fibroblasts were improved with decreasing of grain size. An initial in vivo investigation of biocompatibility by the primary cutaneous irritation test showed that both materials exhibited no irritation properties.

[IPEX syndrome--case report].

INTRODUCTION: IPEX syndrome, namely, a hereditary (X-linked) immunodysregulation with autoimmune polyendocrinopathy and enteropathy, as the basic manifestations, presents a rare and exceptionally severe disease. It develops due to gene mutation responsible for the synthesis of a specific protein (FOXP3), which, by differentiation and activation of regular T-lymphocytic CD4+CD25+, has the key role in the induction and maintenance of the peripheral tolerance of one's own tissue. CASE OUTLINE: We present a male infant with classic clinical features of IPEX syndrome, which manifested by the end of the first month after birth, first with type 1 diabetes mellitus and chronic diarrhoea followed by dehydration and disordered development, and then with facial eczema and laboratory signs of thyroiditis without thyroid dysfunction (antithyreoglobulin antibodies 1:5500, antimicrosomal antibodies 1:40). In addition, plasma IgE level was high (517 IU/l), while antibodies to tissue transglutaminase were mildly increased (IgA 7.5 U/ml), and anti-smooth muscle and anti-DNA antibodies were absent. Based on the typical clinical features, as well as the laboratory findings, IPEX syndrome was diagnosed, which was further confirmed by proved IVS7+5G>A mutations in the FOXP3 gene. Therapy with insulin and Pronison, combined with parenteral and semielementary nutrition resulted in the patient's clinical improvement. At the age of 9 months, despite Pronison and hypoallergenic nutrition, the child had a relapse of severe and persistent diarrhoeal disorder followed by dehydration, weight loss and deterioration of general condition. Beside the complete parenteral nutrition, as well as other measures, azathioprine was introduced into the treatment, but without the desired effect. At the age of 12.5 months, due to bacteraemia and disseminated intravascular coagulation as complications, the patient ended lethally. CONCLUSION: IPEX syndrome should be kept in mind in all the cases of associated type 1 diabetes mellitus and chronic diarrhoea in male neonates or infants. Although treatment results have still been modest, it is quite certain they will be far better in the near future.

[Subclinical peripheral neuropathy in type 1 diabetic adolescents and its relationship with metabolic control].

Professional management of paediatric diabetology, according to consensus guidelines, involves the screening of microvascular complications at puberty. The subclinical form of peripheral neural dysfunction in diabetic teenagers is reported with a frequency of 50-88%, by different authors. The purpose of this study was to evaluate the frequency of subclinical distal neuropathy (DSMN) in type 1 diabetic paediatric patients during the second decade of life, and its relationship with metabolic control. The Endocrinology Department and the Neurology-Physiology Laboratory of the Paediatric Clinic in Belgrade carried out a longitudinal follow-up study (lasting 18 months, beginning in November 2000) on a selection of patients with poor metabolic control. During routine clinical treatment, patients were evaluated using the electrophysiological diagnostic method on peripheral neural dysfunction, a subclinical form of neuropathy. Metabolic control was manifested through HbA1c levels, measured every 3 months, using ion-exchange chromatography. Finally, here is the data collected from the clinical follow-up investigation of 60 children, aged 13-19 (median 15.5 +/- 2.2), with duration of diabetes from 2-16 years (median 6.3 +/- 3.6), and on the following therapies: 43 CT-conventional and 17 IIT-intensive, and insulin dose/ day, median 1.02 (0.6-2.1) U/kg. Detected DSMN parameters at the beginning and at the end of the study were also noted. DSMN frequency was positive, at 64% for HbA1c of 9.44; DSMN dysfunction was reversed in 5% of the patients, for HbA1c of 10.17; the worst result was the progression of DSMN at 6.7% for HbA1c of 10.52; 6.7% had negative DSMN, with improved metabolic control, for HbA1c of 8.4; 15% of the examinations were unfinished (+/*). ANOVA statistical analysis showed a significant statistical relationship between metabolic control (HbA1c levels) and DSMN neuropathy (sig. 0.043, p < 0.05). There was no significant relationship between the reversion of DSMN and improved HbA1c, although a numeric distinction did exist. On the clinical aspect, there was a significant relationship between insulin dosage and age (p < 0.01, sig. 0.007). This data demonstrates the influence of metabolic regulation on neuropathy. Better metabolic control can slow the progression of subclinical peripheral neural dysfunction (DSMN) in diabetic children.