bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitrogen-doped titanium oxide microrods decorated with titanium oxide nanosheets for visible light photocatalysis
Authors: Jang Jum Suk , Kim Eun Sun , Kim Hyun Gyu , Ji Sang Min , Kim Youngkwon , Lee Jae Sung
Published: May 2010

Nitrogen-doped titania with a unique two-level hierarchical structure and visible light photocatalytic activity is reported. Thus, nitrogen-doped titanium oxide microrods decorated with N-doped titanium oxide nanosheets were synthesized by a hydrothermal reaction in NH4OH and postcalcination. During the calcination, the in situ incorporation of nitrogen atoms of ammonium ion into titania lattice was accompanied by the structural evolution from titanate to anatase titania. The morphological and structural evolution was monitored by scanning electron microscopy (SEM), x-ray diffraction (XRD), thermogravimetric analysis/differential thermal analysis (TGA/DTA), Raman, Fourier transform infrared (FTIR), x-ray absorption near edge structure (XANES), x-ray photoelectron spectroscopy (XPS), and adsorption isotherms. The N-doping brought visible light absorption, and the material exhibited high photocatalytic activity in the decomposition of Orange II under visible light irradiation (λ ≥ 400 nm), especially when it was loaded with 1 wt% Pt as a cocatalyst.
Comparison of quasistatic to impact mechanical properties of multiwall carbon nanotube/polycarbonate composites
Authors: Brühwiler Paul A. , Barbezat Michel , Necola Adly , Kohls Doug J. , Bunk Oliver , Schaefer Dale W. , Pötschke Petra
Published: May 2010

We report the quasistatic tensile and impact penetration properties (falling dart test) of injection-molded polycarbonate samples, as a function of multiwall carbon nanotube (MWNT) concentration (0.0–2.5%). The MWNT were incorporated by dilution of a commercial MWNT/polycarbonate masterbatch. The stiffness and quasistatic yield strength of the composites increased approximately linearly with MWNT concentration in all measurements. The energy absorbed in fracture was, however, a negative function of the MWNT concentration, and exhibited different dependencies in quasistatic and impact tests. Small-angle x-ray scattering (SAXS) showed that the dispersion of the MWNT was similar at all concentrations. The negative effects on energy absorption are attributed to agglomerates remaining in the samples, which were observed in optical microscopy and SAXS. Overall, there was a good correspondence between static and dynamic energy absorption.
Accelerated spheroidization induced by high intensity electric pulse in a severely deformed eutectoid steel
Authors: Samuel Edwin I. , Bhowmik Arghya , Qin Rongshan
Published: May 2010

Application of high intensity electric pulse (HIEP) to a severely deformed eutectoid microstructure in high carbon steel wire has resulted in spheroidized microstructure. The observed spheroidization on electropulsing is compared with that reported for isothermal/thermo-mechanical annealing of the pearlite structure. The faster kinetics observed in this study has been rationalized in terms of accelerated kinetics induced by HIEP.
Plastic instability in amorphous selenium near its glass transition temperature
Authors: Su Caijun , LaManna James A. , Gao Yanfei , Oliver Warren C. , Pharr George M.
Published: May 2010

The deformation behavior of amorphous selenium near its glass transition temperature (31 °C) has been investigated by uniaxial compression and nanoindentation creep tests. Cylindrical specimens compressed at high temperatures and low strain rates deform stably into barrel-like shapes, while tests at low temperatures and high strain rates lead to fragmentation. These results agree well with stress exponent and kinetic activation parameters extracted from nanoindentation creep tests using a similarity analysis. The dependence of the deformation modes on temperature and strain rate can be understood as a consequence of material instability and strain localization in rate-dependent solids.
Averting cracks caused by insertion reaction in lithium–ion batteries
Authors: Hu Yuhang , Zhao Xuanhe , Suo Zhigang
Published: May 2010

In a lithium-ion battery, both electrodes are atomic frameworks that host mobile lithium ions. When the battery is being charged or discharged, lithium ions diffuse from one electrode to the other. Such an insertion reaction deforms the electrodes and may cause the electrodes to crack. This paper uses fracture mechanics to determine the critical conditions to avert insertion-induced cracking. The method is applied to cracks induced by the mismatch between phases in LiFePO4.
Enhanced stress relaxation of Sn–3.8Ag–0.7Cu solder by electrical current
Authors: Liu Haiyan , Zhu Qingsheng , Zhang Li , Wang Zhongguang , Shang Jian Ku
Published: May 2010

The stress relaxation responses of the Sn–3.8Ag–0.7Cu joints following exposure to electrical currents were examined to investigate the effect of electromigration on the reliability of solder joints. It was found that the stress relaxation rate was enhanced for the Sn–3.8Ag–0.7Cu solder joints subjected to a current density of 2 × 104 A/cm2. Sn hillock formation was observed in situ on the surface of the solder joint and the increase of the hillock volume was obtained as a function of the current application time. Analysis of the vacancy flux indicated that the variations of the vacancy concentration with the electromigration time from the calculations agreed with the growth kinetics of the hillocks observed in the experiments. By modeling the stress relaxation as a climb-assisted dislocation glide process, it is shown that the vacancy accumulation induced by electromigration enhanced the dislocation climb rate, resulting in a large increase of the stress relaxation rate.
Mechanics analysis of femtosecond laser-induced blisters produced in thermally grown oxide on Si(100)
Authors: McDonald Joel P. , Thouless M.D. , Yalisove Steven M.
Published: May 2010

Blister features produced by laser-induced delamination of silicon dioxide from silicon substrates were analyzed with thin-film buckling mechanics. These analyses revealed the role of the interaction between the material and the femtosecond (fs)-pulsed laser on blister formation. In particular, it was deduced that the magnitude of the compressive residual film stress within the irradiated region appeared to exceed the intrinsic residual stress obtained from wafer curvature techniques. This apparent increase in the compressive stress after fs-pulsed laser irradiation may be caused by a modification of the oxide, which resulted in a local rarefaction of the film. The results demonstrated important features of the interaction between materials and fs-pulsed laser, including the presence of subtle modification thresholds and the limited role of thermal effects.
Microstructure investigations of Pt-modified γ′-Ni3Al + γ-Ni coatings on Ni-based superalloys
Authors: Cao Guanghui , Ou Taoping , Jiang Hua , Russell Alan M.
Published: May 2010

The microstructure of Pt-modified γ′-Ni3Al + γ-Ni coating on CMSX-4 single-crystal superalloy has been investigated by transmission electron microscopy (TEM). Cross-sectional TEM analyses showed the presence of precipitates in the coating. This precipitate was identified as the hexagonal topologically close-packed (TCP) μ phase with lattice parameters a = 0.473 nm and c = 2.565 nm. The energy-dispersive x-ray (EDX) spectrum of the μ phase suggested a refractory element rich compound comprising the elements Re, W, and Co. Twin domains parallel to (001) were found in the μ phase. The mechanisms of the μ phase and twinning formation were discussed.
Electrical investigations of holmium-doped BaTiO3 derived from sol-gel combustion
Authors: Cernea Marin , Galassi Carmen , Vasile Bogdan S. , Ganea Paul , Radu Roxana , Ghita Georgiana
Published: May 2010

Holmium-doped BaTiO3 with composition Ba0.97Ho0.03TiO3 was prepared by sol-gel combustion method. A molar ratio of citrate/nitrate (CA/NO3− = 1.3) was used to prepare nanopowders of (Ba,Ho)TiO3. The structure and microstructure of (Ba,Ho)TiO3 powders and ceramics were investigated. The ceramics exhibit a dielectric constant of about 4400 and dielectric loss (tan δ = 0.267) at 10 Hz, and at the Curie temperature (Tc = 132 °C). The remanent polarization and the coercive field of Ba0.97Ho0.03TiO3 ceramics, at 1 kHz, were Pr = 6 μC/cm2 and EC = 0.75 kV/cm. The dielectric and ferroelectric behavior of the holmium-doped BaTiO3 is influenced by the amphoteric character of Ho3+ ions.
Cubic ZnxMg1−xO thin films grown by plasma-assisted molecular-beam epitaxy for optoelectronic applications
Authors: Mares J.W. , Boutwell R.C. , Scheurer A. , Schoenfeld W.V.
Published: May 2010

Heteroepitaxial ZnxMg1−xO thin films were grown on lattice-matched MgO (100) substrates using radiofrequency plasma-assisted molecular-beam epitaxy. High-quality epilayers with zinc concentrations ranging from x = 0 (MgO) to x = 0.65 were grown and characterized optically, structurally, and electrically. The ZnxMg1−xO films were found to maintain the rocksalt cubic (B1) crystal structure for concentrations z < 0.65, with a linear dependence of lattice constant on Zn concentration. X-ray diffraction (XRD) also revealed the emergence of phase segregation into wurtzite (B4) phase for the highest concentration film. The band gap energy of the films was successfully varied from 4.9 to 6.2 eV (253–200 nm), showing a linear relationship with Zn concentration. The strictly cubic films exhibit roughness on the order of 10 Å and resistivities of approximately 106 Ω·cm.
Initial stages of oxidation of Ti45Al7Nb0.4Y alloy at 900 °C in air
Authors: Zhao L.L. , Lin J.P. , Zhang L.Q. , Song X.P. , Ye F. , Chen G.L.
Published: May 2010

The initial stage of oxidation of Ti45Al7Nb0.4Y alloy (at.%) oxidized at 900 °C in air was investigated by using x-ray photoelectron spectroscopy and Auger electron spectroscopy. Experimental results revealed that YAl2 segregated along the grain boundaries preferentially oxidized to Y2O3 and Al2O3 due to strong affinity of Y to oxygen. Oxides grew faster at the grain boundaries than in lamellar colonies. As a result, Y and Al oxides pegs protruded into the substrate, which can increase the contact areas of oxide scale and substrate. Moreover, inward diffusion of oxygen more easily occurred along the grain boundaries. As a result, it promoted the external oxidation of Al within the grains due to lower inward diffusion flux of oxygen. And coarse-grained Y2O3 blocked the cationic intergranular diffusion. Therefore, Y addition can effectively enhance the Al2O3 layer and suppress the TiO2 outermost layer.
Thermal oxidation mechanism and stress evolution in Ta thin films
Authors: Jin Yusung , Song Jae Yong , Jeong Soo-Hwan , Kim Jeong Won , Lee Tae Geol , Kim Ju Hwang , Hahn Junhee
Published: May 2010

Oxidation-induced stress evolutions in Ta thin films were investigated using ex situ microstructure analyses and in situ wafer curvature measurements. It was revealed that Ta thin films are oxidized to a crystalline TaO2 layer, which is subsequently oxidized to an amorphous tantalum pentoxide (a-Ta2O5) layer. Initial layered oxidation from Ta to TaO2 phases abruptly induces high compressive stress up to about 3.5 GPa with fast diffusion of oxygen through the Ta layer. Subsequently, it is followed by stress relaxation with the oxidation time, which is related to the slow oxidation from TaO2 to Ta2O5 phases. The initial compressive stress originates from the molar volume expansion during the layered formation of TaO2 from the Ta layer, while the relaxation of the compressive stresses is ascribed to the amorphous character of the a-Ta2O5 layer. According to Kissinger's analysis of the stress evolution during an isochronic heating process, the oxygen diffusion process through the a-Ta2O5 layer is the rate-controlling stage in the layered oxidation process of forming a a-Ta2O5/TaO2/Ta multilayer and has an activation energy of about 190.8 kJ/mol.
The Role of Surgery and Radiation Therapy in the Management of Gestational Trophoblastic Disease
Authors: Hanna Rabbie K. , Soper John T.
Published: May 2010

Learning Objectives

After completing this course, the reader will be able to: Describe the indications for surgical intervention in the management of patients with hydatidiform moles and malignant GTN in order to choose patients most likely to benefit from these interventions.Discuss the use of radiation in the management of patients with malignant GTN and consider its use as an adjunct to chemotherapy or surgery.

CME This article is available for continuing medical education credit at CME.TheOncologist.com

The primary management of hydatidiform moles remains surgical evacuation followed by human chorionic gonadotropin level monitoring. Although suction dilatation and evacuation is the most frequent technique for molar evacuation, hysterectomy is a viable option in older patients who do not wish to preserve fertility. Despite advances in chemotherapy regimens for treating malignant gestational trophoblastic neoplasia, hysterectomy and other extirpative procedures continue to play a role in the management of patients with both low-risk and high-risk gestational trophoblastic neoplasia. Primary hysterectomy can reduce the amount of chemotherapy required to treat low-risk disease, whereas surgical resections, including hysterectomy, pulmonary resections, and other extirpative procedures, can be invaluable for treating highly selected patients with persistent, drug-resistant disease. Radiation therapy is also often incorporated into the multimodality therapy of patients with high-risk metastatic disease. This review discusses the indications for and the role of surgical interventions during the management of women with hydatidiform moles and malignant gestational trophoblastic neoplasia and reviews the use of radiation therapy in the treatment of women with malignant gestational trophoblastic neoplasia.
Dual-mode, Fluxgate-Induction Sensor for UXO Detection and Discrimination
Authors: Zhang Yongming , Steiger Matthew , Hibbs Andrew D. , Grimm Robert E. , Sprott Thomas A.
Published: May 2010

We describe an innovative, dual-mode, fluxgate-induction sensor (FIS) that combines a DC magnetometer and an electromagnetic (EM) sensor. This sensor will enable one-pass unexploded ordnance (UXO) detection and discrimination using the joint measurements. The FIS is based on a [Formula: see text] long, high-permeability magnetic core and a sensing coil that are shared by both EM and magnetic (MAG) modes. This integration makes the sensor very compact and removes the potential crosstalk problem of the core material of one sensor dominating the response of the other. A prototype receiver was developed and true serial, dual-mode operation demonstrated. The FIS achieved sensitivities of [Formula: see text] rms in MAG mode and [Formula: see text] at [Formula: see text] in EM mode, which compare favorably to existing commercial instruments. Triaxial dipole modeling confirms that three-component EM data are better for shape characterization than one (vertical) component. Assuming axisymmetry, inversions of three-component EM measurements of 22 cylindrical and disk-shaped targets yielded 100% correct classification of UXO-like objects (cylinders) and 38% misclassification of disks as cylinders. Degraded classification performance with increasing vertical distance may be caused by the small cross-sectional area of the FIS; an array will provide better field sampling. Triaxial dipole modeling of the MAG data confirmed its utility for detecting deeper targets using only the vertical component. Based on these results, the FIS is ready for field demonstration and validation.
Seismic Prediction While Drilling (SPWD): Looking Ahead of the Drill Bit by Application of Phased Array Technology
Authors: Jaksch K. , Giese R. , Kopf M. , Jurczyk A. , Mikulla S. , Weisheit S. , Groh M. , Krüger K.
Published: May 2010

Abstract. No abstract available.

doi:10.2204/iodp.sd.9.06.2010
The influence of pet containers on antimony concentration in bottled drinking water
Authors: Peric-Grujic Aleksandra , Radmanovac Aleksandar , Stojanov Aleksander , Pocajt Viktor , Ristic Mirjana
Published: May 2010

Antimony trioxide (Sb2O3) is the most frequently used catalyst in the polyethylene terephthalate (PET) manufacture. As a result, antimony is incorporated into PET bottles at concentration level of 100-300 mg/kg. PET containers are used for drinking water and beverages, as well as food packaging and in the pharmaceutical industry. Thus, it is important to understand the factors that may influence the release of antimony from the catalysts into water and other products, since antimony is potentially toxic trace element. In this paper, the antimony content in nine brands of bottled mineral and spring water from Serbia, and seven brands of bottled mineral and spring water from EU countries was analyzed. The measurements were conducted using the inductively coupled plasma-mass spectrometry (ICP-MS) technique. In the all examined samples the antimony concentration was bellow the maximum contaminant level of 5 ?g/L prescribed by the Serbian and EU regulations. Comparison of the content of antimony in PET bottled waters with the content of antimony in water bottled commercially in glass and the natural content of antimony in pristine groundwaters, provides explicit evidence of antimony leaching from PET containers. Since waters bottled in PET have much greater concentration ratio of Sb to Pb than corresponding pristine groundwaters, it can be assumed that bottled waters cannot be used as the relavant source for the study of the natural antimony content in groundwaters. There is a clear relation between the quality of water in bottles (composition, ion strength) and antimony leaching rate. Moreover, while the rate of antimony leaching is slow at temperatures below 60 oC, at the temperature range of 60-80 oC antimony release occurs and reaches maximum contaminant level rapidly. As antimony can cause both acute and chronic health problems, factors that promote the increase of antimony concentration should be avoided.
An overstoichiometric Nd-Fe-B hard magnetic material
Authors: Zák Tomás , Talijan Nadezda , Cosovic Vladan , Stajic-Trosic Jasna , Grujic Aleksandar
Published: May 2010

A commercial Nd-rich Nd-Fe-B-based hard magnetic material was studied. The obtained results were compared before and after recording of the thermomagnetic curve up to 800?C. The curve itself showed clearly besides Curie points of the Nd2Fe14B phase and ?-Fe also another critical temperature. M?ssbauer spectroscopic (MS) phase analysis and X-Ray diffraction analysis (XRD) showed in addition to the commonly known phases Nd2Fe14B and NdFe4B4 also some paramagnetic and ferromagnetic iron atoms (MS) and Fe17Nd2 intermetallics (XRD). During the exerted thermal treatment, the content of the Nd2Fe14B and NdFe4B4 phases remained almost unchanged, while iron atoms from remnant minor phases built a separate ?-Fe phase. The XRD pattern also showed the presence of some minor Nd phase. The results of SQUID magnetic measurements suggest a nanocrystalline decoupled structure of the Nd-rich alloy in the optimized magnetic state. Measurement of the magnetization loop showed, in spite of small changes in the phase composition, that magnetic properties of the quality material deteriorated during the thermal treatment.
Synthesis and crystal structure of 1,2,3,4-tetrahydro-9-aminoacridine tetrachlorozincate(II) monohydrate
Authors: Miodragovic Djenana , Jovanovic Dragoljub , Bogdanovic Goran , Mitic Dragana , Andjelkovic Katarina
Published: May 2010

In the reaction of ZnCl2 with tacrine hydrochloride in water novel tetracoordinated (C13H15N2)2[ZnCl4].H2O complex was obtained and characterized by elemental analysis, molar conductivity and X-ray analysis. The complex crystallizes in the space group P-1 of the triclinic crystal system. The structure contains two crystallographically different molecules of protonated tacrine present as counter cations, the [ZnCl4]2- complex anion and one water solvent molecule. The counter cations slightly differ in the puckering of the cyclohexenyl ring. The molecules of protonated tacrine are involved in different intermolecular hydrogen bonds. In the crystal, the hydrogen bonding generates a 3D assembly. In the crystal, p...p stacking interactions between the rings of protonated tacrine were evidenced. The [ZnCl4]2-complex anion has a distorted tetrahedral geometry. Three out of the four Cl atoms are involved in intermolecular hydrogen bonding. The intermolecular H-bond interactions involving the Cl atoms affect the Zn-Cl bond lengths.
Comparative analysis of electroencephalographic tests of alpha activity attenuation in evaluation of involuntary falling asleep in healthy adults
Authors: Sundric Zvonko , Rajsic Nenad , Lakocevic Milan , Nikolic-Djoric Emilija
Published: May 2010

Introduction. Decrease of daily alertness is a common cause of accidents in the work place, especially traffic accidents. Therefore, an increasing interest exists to determine reliable indicators of a tendency to fall asleep involuntarily. Objective. To determine an optimal electroencephalographic (EEG) indicator of an involuntary tendency to fall asleep, we performed a study on neurologically healthy subjects, after one night of sleep deprivation. Total sleep deprivation was aimed at increasing daily sleepiness in healthy subjects, providing us with an opportunity to test different methods of evaluation. Methods. We applied a visual analogue scale for sleepiness (VASS), EEG registration with the specific test of alpha activity attenuation (TAA) in 87 healthy subjects. The test was performed in a standard way (sTAA) as well as in accordance with new modifications related to changes of EEG filter width in the range from 5 to 32 Hz (mTAA). Results. After sleep deprivation, we observed involuntary falling asleep in 54 subjects. The comparison of VASS results showed no differences, contrary to a more objective TAA. Between two variants of TAA, the modified test provided us with a better prediction for subjects who would fall asleep involuntarily. Conclusion. The application of a more objective EEG test in evaluation of daily alertness represents the optimal method of testing. Modified TAA attracts special attention, offering a simple solution for reliable testing of decreased daily alertness in medical services related to professional aircraft personnel.
In vitro evaluation of microleakage of various types of dental cements
Authors: Medic Vesna , Obradovic-Djuricic Kosovka , Dodic Slobodan , Petrovic Renata
Published: May 2010

Introduction. Microleakage is defined as the clinically undetectable seepage of oral fluids containing bacteria and debris between cement layer and tooth restoration. Objective. This in vitro study investigated the effect of different dental cements (zinc-phosphate, polycarboxylate, glass-ionomer and resin cement) on microleakage in different ceramic crown systems (metal ceramic crown, metal ceramic crown with a porcelain margin, Empress 2 and In Ceram all-ceramic crowns) fixed on extracted human teeth. Methods. One hundred and sixty intact human premolars were randomized to four groups of forty teeth each, according to the different ceramic crown systems. They were prepared in a standardized manner for metal-ceramic and all-ceramic crowns. Crowns were made following a standard laboratory technique, and each group of crowns were divided into four groups according to the different cement agents and cemented on their respective abutments. The specimens were subjected to thermocycling, placed in methylene blue solutions, embedded in resin blocks and vertically cut in the bucco-oral and meso-distal direction. The microleakage in the area of tooth-cement interface was defined as linear penetration of methylene blue and was determined with a microscope to assign microleakage scores using a five-point scale. Results. A significant association was found between a cement type and degree of microleakage (p=0.001). No statistically significant differences were found among the different ceramic crown systems luted with the same dental cement. The smallest degree of microleakage was observed in specimens luted with resin cement (X=1.73), followed by glass-ionomer cement (X=2.45) and polycarboxylate cement (X=3.20). The greatest degree of microleakage was detected in the crowns fixed with zincphosphate cement (X=3.33). Conclusion. The investigated dental cements revealed different sealing abilities. The use of resin cement resulted in the percentage of 0 microleakage scores. Due to this feature, the resin cement is to be recommended in everyday clinical practice.
Relationship between mortality of patients with atrial fibrillation and mortality of general population in Serbia
Authors: Potpara Tatjana , Grujic Miodrag , Marinkovic Jelena , Ostojic Miodrag , Vujisic-Tesic Bosiljka , Polovina Marija , Mujovic Nebojsa , Kocijancic Aleksandar
Published: May 2010

Introduction. Large population-based observational trials have shown atrial fibrillation (AF) to be an independent risk factor for increased mortality. Objective. To examine all-cause mortality and cardiovascular mortality of patients with AF compared to corresponding mortality in general population of Serbia. Methods. This longitudinal observational study included patients with nonvalvular AF as the main indication for in-hospital and/or outpatient treatment at the Clinical Centre of Serbia, Belgrade, during the period 1992-2007, if the latest date of the first diagnosed AF was early January 2003, so that the total follow-up could last at least 5 years (minimum 1 year prospectively), or until death. Patients with acute causes of AF, advanced left ventricular systolic dysfunction (LVEF?25%), preexcitation, known malignancy or any advanced chronic disease and patients with poorly documented history of previous AF were not included. To compare mortality of study population with mortality of general population, we used standardized mortality ratio (SMR) and chi-square test, p<0.05. Results. Out of 1,100 patients (389 females, 35.4%), aged 52.7?12.2 years, with total follow-up 9.94?6.05 years (prospective 5.75?4.28, retrospective 4.21?5.51), 40% had no underlying disease; others most frequently had arterial hypertension. AF was paroxysmal in 665 (60.5%), persistent in 225 (20.5%) and permanent in 210 patients (19.1%). Newly diagnosed AF was documented in 1058 patients (96.2%). Until the end of the study, 85 patients died (7.7%). Cardiovascular death was noted in 62 patients (72.9%), most frequently in form of sudden death (27/85, 31.7%), death from congestive heart failure (18/85, 21.2%) and stroke (14/85, 16.5%). Most patients (67/85, 78.8%) had AF at the time of death. SMR for all-cause mortality was 2.43 (p<0.0001) and for cardiovascular mortality 3.03 (p<0.0001). Conclusion. All-cause mortality and cardiovascular mortality of AF patients are higher than corresponding mortality in general population of Serbia, despite active treatment.
Normal values of cerebral blood flow velocities in neonates
Authors: Vasiljevic Brankica , Gojnic Miroslava , Maglajlic-Djukic Svjetlana , Antonovic Olga
Published: May 2010

Introduction. There was used color Doppler ultrasonography (cD-USI), allowing simultaneous examination of parenchymal and vascular cerebral structures. The evaluation of blood flow velocities in cerebral arteries is important in the assessment of cerebral circulation in hypoxic-ischaemic and haemorrhagic brain damage in neonates. Objective. The aim of this study was to estimate normal values of cerebral blood flow velocities (CBFV) and Doppler indices - pulsatility index (PI) and resistance index (RI) - in the anterior cerebral artery (ACA) during the first days of life in infants. Methods. CBFV, PI and RI were obtained during the first week of life with cD-US in 70 infants divided in four groups of gestational age (GA): ?28 gestational weeks (GW); 29-32 GW; 33-36 GW; and ?37 GW. Infants with congenital malformations, severe perinatal asphyxia, cerebral haemorrhagic lesion, DAP or severe hypotension were excluded. Results. The mean GA of infants was 34.5?5.5 GW (range 26-40 GW) and the mean birth weight (BW) was 2540?950 g (range 750-4000 g). In the 1st group of 10 infants, ?28 GW, the mean BW was 950?110 g and values of RI were 0.59?0.10 and PI 1.06?0.080. In the 2nd group of 20 infants, 29-32 GW, the mean BW was 1350?290 g and values of RI were 0.60?0.10 and PI 1.10?0.15. In the 3rd group of 20 infants, 33-36 GW, the mean BW was 1950?750 g and values of RI were 0.63?0.08 and PI 1.15?0.30. In the 4th group of 20 infants, ?37 GW, the mean BW was 3540?950 g and values of RI were 0.65?0.05 and PI 1.18?0.35. Conclusion. Values of CBFV progressively increase with GA and BW due to progressive increase of cardiac output, blood pressure and closing of ductus arteriosus. Values of RI and PI gradually increase with GA and BW as a result of progressive maturation and opening of vascular cerebral bed with a reduction of the cerebrovascular resistance.
Recombinant human growth hormone treatment in short children with renal disease: Our first experience
Authors: Spasojevic-Dimitrijeva Brankica , Kostic Mirjana , Peco-Antic Amira , Kruscic Divna , Cvetkovic Mirjana , Milosevski-Lomic Gordana , Paripovic Dusan
Published: May 2010

Introduction. Growth retardation is a hallmark of chronic illnesses such as chronic kidney disease in children, and it is associated with increased morbidity and mortality. The growth hormone (GH) resistance observed in uraemia can be overcome by supraphysiological doses of exogenous GH. Objective. We would like to present our first results of recombinant human growth hormone (rhGH) treatment, mainly in children on haemodialysis. Methods. Sixteen children, aged 4.5-17.1 years (mean age 11.25?3.57) with height below -2.0 standard deviation score (SDS) for age or height velocity below -2.0 SDS for age, were selected to receive rhGH therapy at our Nephrology and Haemodialysis Department. Most of them were on haemodialysis (14 children) with mean spent time 2.88?2.68 years (0-9 years) before the initiation of rhGH therapy. One half of patients were prepubertal (8 children) and the second half were in early puberty (testicular volume between 4 and 8 ml for boys and breast development B2 or B3 in girls). All patients received 28-30IU/m? rhGH per week by daily subcutaneous injection. The year before rhGH therapy served as a control period. Results. During the first year of treatment, mean height velocity in haemodialysis patients increased from 2.25 cm/year to 6.59 cm/year (p<0.0001) and in the second year it was 5.25 cm/ year (p=0.004). The mean height SDS in haemodialysis children did not improve significantly during the first year of rhGH treatment (from -3.01 SDS to -2.77 SDS, p=0.063). Neither weight nor the body mass index varied compared with the pretreatment period. Two patients developed worsened secondary hyperparathyroidism and were excluded from the study, but the relationship with rhGH remains uncertain. Conclusion. Mean height velocity significantly improved during rhGH therapy in haemodialysis patients. No significant side-effects were observed in children during three-year treatment with GH.
Risk of HIV infection among indoor and street sex workers and their use of health services in Belgrade, Serbia
Authors: Ilic Dragan , Sipetic Sandra , Bjegovic Vesna
Published: May 2010

Introduction. HIV in Serbia is most often transmitted through sexual contact, and therefore numerous prevention activities are geared towards sex workers (SW). Objective. To analyze the differences in knowledge, attitudes and risky behaviour between indoor and street SW in Belgrade; to examine the accessibility of health services to this vulnerable group. Methods. In this behavioural cross-sectional study, 113 street and 78 indoor SW were included. The sampling method used was snowball samples. Data were gathered through structured questionnaires. Results. Around 15% of respondents used drugs intravenously. Around 60% of SW used a condom during the last sexual intercourse with their private partner, and around 90% with a commercial partner. Indoor SW had lower levels of education more often than outdoor SW, and they used marijuana, sedatives and painkillers on a daily basis. A significantly higher number of indoor SW were informed about HIV, HBV and HCV testing, and that the risk for HIV infection is not lower if a condom is used exclusively for vaginal sex. Indoor SW reported using health services and testing and counseling for HIV, HBV and HCV more frequently than outdoor SW. Outdoor SW had significantly more sex partners in the previous month than indoor SW. Indoor SW recognized more frequently that providing sex services posed a higher risk for HIV infection. Conclusion. The results of this research study show that even though outdoor SW had higher levels of education than indoor SW, their level of knowledge about HIV transmission was lower and they reported more risky behaviour than indoor SW. Data show that both groups reported not taking care of their health.
Resection of thrombosed femoral artery over-dimensional stent-graft placed due to multiple arteriovenous fistulas following gunshot wounds
Authors: Radak Djordje , Tanaskovic Slobodan , Nenezic Dragoslav , Vucurevic Goran , Popov Petar , Gajin Predrag , Babic Srdjan , Aleksic Nikola , Milicic Miroslav , Matic Predrag , Ilijevski Nenad
Published: May 2010

Introduction. Though surgical approach is common in arteriovenous (AV) fistula treatment, endovascular procedures such as stent-graft placement has become more popular in recent years. We aim to present a case of thrombosed femoral artery stent-graft which was placed one year earlier due to multiple AV fistulas following gunshot wounds. Case Outline. A 43-year-old patient was admitted to the Institute for Cardiovascular Diseases 'Dedinje', Belgrade, Serbia, for arteriography. Five years before, he had suffered from six gunshot wounds in his right leg and one year before, in the health centre in Vienna, stent-graft had been placed in the right superficial femoral artery due to multiple AV fistulas. Because of artery dilation proximal to AV fistula location, a large dimensional stent-graft had to be placed (24 mm). After admission, arteriography and Multislice CT (MSCT) angiography revealed thrombotic masses in the stent-graft with intraluminal stenosis of 50%. Extirpation of thrombosed stent-graft was performed followed by Dacron tubular graft 10 mm interposition. On the fifth postoperative day, the patient was discharged from the clinic, and after 3 months, the right leg vascularisation was well preserved. Conclusion. Large dimensional stent-graft placement in patients with mutiple AV fistulas and blood vessel dilation proximal to AV site of communication carries an increased risk of thrombotic events due to turbulent blood flow and parietal thrombosis occurrence. Though stent-graft placement can be a very useful solution in acute AV fistula treatment, the very same thrombosis should be thought of when surgical management is the only treatment choice.
Late onset of severe thrombocytopenia during interferon treatment for chronic hepatitis C infection: Case report
Authors: Hajder Jelena , Stanisavljevic Natasa , Markovic Olivera , Marisavljevic Dragomir
Published: May 2010

Introduction. Thrombocytopenia is a common finding in chronic liver diseases and it is caused by different pathophysiological mechanisms. Immunologic thrombocytopenic purpura (ITP) in hepatitis C infection is a distinct clinical entity. Possible reasons for ITP in this case could be capabillity of HCV to induce autoimmune phenomena but also immunomodulatory effects of interferon that is used for HCV infection treatment. The specific laboratory parameters for ITP diagnosis during HCV infection have not been defined yet. Case Outline. A 37-year-old patient diagnosed with HCV infection was treated with PEG-interferon and Ribavirin during 24 weeks. The partial response was achieved after the therapy with reduction of viral replications. One month after therapy completion, the patient was hospitalized due to skin haemorrhagic syndrome and a serious degree of thrombocytopenia (2?109/l). The number and megakaryocyte morphology in bone marrow aspirate were normal. An assay of thrombocyte kinetics by radioactive marker (Indium 111) showed rapid thrombocyte destruction and their early seljuestration in the spleen. Conclusion. Results of assays about thrombocyte kinetics during HCV infection show enchanced thrombocyte destruction in the liver. Accordingly, the most important parameter for ITP diagnosis in HCV infection, in this case, was rapid thrombocyte destruction and their early sequestration in the spleen approved by Indium kinetics. Also, in support of ITP is the increment of thrombocyte number during therapy with intravenous immunoglobulins. Thrombocytopenia was developing during antiviral therapy and on indirect conclusion is that viral replication is not the reason for it.
Glucagonoma without glucagonoma syndrome
Authors: Colovic Radoje , Matic Slavko , Micev Marjan , Grubor Nikica , Latincic Stojan
Published: May 2010

Introduction. Glucagonomas are rare, frequently malignant tumours, arising from the Langerhans' islets of the pancreas. They usually secrete large amounts of glucagon that can cause a characteristic 'glucagonoma syndrome', which includes necrolytic migratory erythema, glucose intolerance or diabetes, weight loss and sometimes, normochromic normocytic anaemia, stomatitis or cheilitis, diarrhoea or other digestive symptoms, thoromboembolism, hepatosplenomegaly, depression or other psychiatric and paraneoplastic symptoms. In certain cases, some or all glucagonoma symptoms may appear late, or even may be completely absent. Case Outline. The authors present a 43-year-old woman in whom an investigation for abdominal pain revealed a tumour of the body of the pancreas. During operation, the tumour of the body of the pancreas extending to the mesentery measuring 85?55?55 mm was excised. Histology and immunohistochemistry showed malignant glucagonoma, with co-expression of somatostatin in about 5% and pancreatic polypeptide in a few tumour cells. The recovery was uneventful. The patient stayed symptom-free with no signs of local recurrence or distant diseases 15 years after surgery. Conclusion. Glucagonoma syndrome may be absent in glucagonoma tumour patients so that in unclear pancreatic tumours the clinician should frequently request the serum hormone level (including glucagon) measurement by radioimmunoassay and the pathologist should perform immunohistochemistry investigation. Those two would probably result in discovery of more glucagonomas and other neuroendocrine tumours without characteristic clinical syndromes.
Effect of halogene light source on marginal microleakage of resin composite restorations
Authors: Gajic Natasa , Djeri Aleksandra , Kojic Zeljka , Trtic Natasa
Published: May 2010

Introduction. Although the technology of production resin composite materials has been improved in the past years, polymerization shrinkage and microleakage still remain the main problem of the resin composite restorations. The most important issues are polymerization control, light source choice, quality and polymerization technique. The aim of this study was to evaluate the effect of the halogen light source on the marginal microleakage of the resin composite restorations class V. Material and Methods. The study included 40 extracted human teeth (20 intact and 20 with caries lesion). Class V cavity was prepared in each tooth. The light curing unit used in this study had irradiance 540 mW/cm2. Cavities were restored with the two resin composite materials, Filtek Supreme (3M ESPE) and Luksogal - Galenika. Microleakage was determined using colored solution of 50% silver-nitrate. Results were obtained using stereomicroscope with 6 times magnification. Color penetration was evaluated on the occlusal and gingival wall. Results. Linear color penetration was observed in all cavities restored using Luksogal. There was significant difference (p<0.01) in color penetration between the occlusal (20.30 ?m) and gingival wall (34.00 ?m). Color penetration was shown in all cavities prepared on intact and caries teeth and restored using Filtek Supreme. Also, color penetration on the occlusal wall (13.80 ?m) was significantly lower (p<0.01) than the penetration on the gingival wall (33.00 ?m). Conclusion. All the tested cavities showed marginal leakage, regardless the tooth or material used. Greater microleakage was noticed when Luksogal was used.
Deformations of the manual endodontic instruments during root canal instrumentation
Authors: Neskovic Jelica , Damjanov Marija , Zivkovic Slavoljub , Grga Djurica , Koruga Djuro , Kojic Dusan
Published: May 2010

Introduction. Mechanical instrumentation of the complex root canal system is very demanding procedure which requires use of the various manual and rotary instruments. The aim of this study was to assess the frequency and to verify the possible deformation of the working part of endodontic instruments after their multiple clinical use. Material and Methods. New sets of the manual endodontic instruments (reamers, K-files and Hedstroem) used in routine clinical use (44 instruments) and for root canal instrumentation of extracted teeth (44 instruments) were included in the study. Instrumentation was performed by Step-Back technique and constant irrigation with 0.5% NaOCl solution, 10 ml for each root canal. All the instruments were used 10 times and after use sterilized in a dry sterilizer or autoclave. The working parts of deformed instruments were analyzed using optimagnetic print. Results. The results obtained after clinical use showed deformations of the working part of the reamers in 50%, K-files in 43% and Hedstroem in 66.7% of used instruments. After instrumentation the canal of the extracted teeth, deformations were observed in 87.5% of the reamers, in 50% of the K-files and in 62.5% of Hedstroem files. The difference in frequency of the deformations was not statistically significant. On the instruments used for the preparation the canals of the extracted teeth and sterilized in autoclave, malformations were observed in 86.4%, comparing to the instruments sterilized in a dry sterilizer where malformations of the working part were registered in 59.1% of the cases. That difference was statistically significant (?2=5.250; p=0.072). Conclusion. Multiple use of the manual endodontic instruments in clinical conditions leads to increased frequency of malformations of the working part in all types of manual endodontic instruments.
Possible errors during the optical impression procedure
Authors: Todorovic Aleksandar , Lisjak Dejan , Lazic Vojkan , Spadijer-Gostovic Aleksandra
Published: May 2010

Introduction. Modern technologies offer a range of benefits and significantly improve specific therapeutic procedures in dentistry. However, despite gaining experience and training there are still some mistakes in their implementation. The aim of this study was to describe the most common errors during intraoral scanning, 'optical impression' procedure, during CAD-CAM technology for production of dental restorations. Material and Methods. Cerec? 3D CAD-CAM system for one visit tooth reconstruction by inlays, onlays, endocrowns, half and complete crowns and veneers from the ceramic material was used in the study. Results. Analysis included 1564 reconstruction during 5 years. The most common causes of errors performing optical impression were the result of: improper preparation of teeth, the instability of the scanner in the mouth of the patient, incorrect position and angle of the scanner to the object scanning, contrast spray applied in uneven layer, the presence of fluid in the region scan, the presence of artifacts in the region gingival sulcus. Conclusion. Optical impression is faster procedure than conventional impression, but technologically sensitive. The most frequent errors are: improper handling of the scanner, inadequate tooth preparation, irregular powder application on the tooth and irregular use in the gingival sulcus.
Factors for therapeutic effect of metal used in prosthetic dentistry
Authors: Zivko-Babic Jasenka
Published: May 2010

Placing building materials, as part of prosthetic therapy, in changeable corrosive and biomechanical environment such as mouth, can cause mechanical irritation, technical failure and/or symptoms of allergic reaction. Interaction between the organism and biomaterial is very complex and defined as biocompatibility or biodegradation. It depends on contact place, structure of the cast, surface workability, oral hygiene as well as on patient's health and use of medicine. Symptoms of systemic diseases that can manifest in the mouth cannot be excluded. Factors for successful prosthetic therapy are: to know patient's general and dental anamnesis, the structure and properties of the materials and to keep records of all previous treatments.
Development of a new composite system: fire resistant and highly structural
Authors: González J. , Ranz D. , Márquez J. A. , Miravete A.
Published: May 2010

Infrastructure and rail sectors share two singularities in terms of materials: highly structural performance and strict fire requirements. Moreover, there is a common growing interest in both sectors: the use of organic matrix composite materials due to their high performance, lightweight and in-service behavior. Traditionally, fire fillers have been added to the matrix, decreasing its mechanical performance in a critical way.

A study about composite materials formed by three different matrices and four different carbon fibers will be presented in this paper. A number of laminates have been manufactured by using these composite materials in order to analyze both the resin processing and the compatibility of the different matrices and fibers. This study is a need due to the fact that these matrices are fire-related and therefore further problems may arise in comparison with standard matrices.
State of the art of TiO2 containing cementitious materials: self-cleaning properties
Authors: Maury A. , De Belie N.
Published: May 2010

Due to the physico-chemical characteristics of cementitious materials the aesthetic quality of these materials tend to decrease easily. On the other hand, the photocatalytic activity produced by TiO2 loaded cementitious materials have recently allowed them to include self-cleaning and air-purifying properties. However, because a better understanding of these properties is still needed, only a limited number of these materials is present in the construction market. As a strategy to improve this situation, non standards tests based on photodegradation of organic dyes have become widely used to evaluate the photocatalytic action of the different materials. Today, a wide spectrum of non easily comparable results have been produced. In order to improve this situation, this paper focuses on the description of the developed laboratory tests as well as on the evaluation of the self-cleaning potential of the first buildings containing TiO2. Finally, future research challenges in this field are identified.