bluuebunny/crossref_metadata_2025 huggingface dataset:
The new ISO and CEN standards for quality and accreditation of medical laboratories
Authors: Desmond Kenny
Published: August 2005

The new international standard EN ISO 15189:2003 ?Medical laboratories - particular requirements for quality and competence?, after many delays, was finally published in February 2003. This standard has been developed specifically to address requirements for accreditation of medical laboratories. It takes into account the special constraints imposed by the medical environment and the essential contribution of the medical laboratory service to patient care. It recognizes that medical laboratories provide not only testing of patient samples, but also advisory, interpretative and educational services. It also acknowledges the role of diagnostics manufacturers in maintaining the quality of medical laboratory services. The international standard ISO/IEC 17025 ?General requirements for the competence of testing and calibration laboratories? is already used in some countries for accreditation of medical laboratories. This is a standard which was developed mainly for use in industrial testing laboratories, and has serious deficiencies when used in the medical environment. While still in draft form, 15189 was already approved by ILAC (International Laboratory Accreditation Co-operation) as a suitable basis for accrediting medical laboratories. It is expected that this document will be used widely in Europe and throughout the world as the preferred standard for this purpose. An informal survey of FESCC member societies shows that 15189, alone or in combination with other standards, will be used in almost all European countries for accreditation of medical laboratories. A further complementary standard, ISO 15190 ?Medical laboratories - requirements for safety? has now been published. A standard for quality and competence in Point Of Care Testing (POCT) is under development, and will be published as a new Annex to EN ISO 15189. These standards will for the first time provide a common basis for the development of quality systems and requirements for competence in medical laboratories throughout the world.
Accreditation
Authors: Huisman Willem
Published: August 2005

ISO 15189 is very well accepted as the principle standard for accreditation of medical laboratories in the European countries. In cooperation with the EA linked national accreditation bodies mutual lateral agreement is well accepted for this standard. It makes it possible that the accreditation is accepted in other countries. Medical laboratory professionals play a key role in the assessment process. Their choice, training and constant education are essential to ascertain that accreditation adds value in the treatment of the patients. It should contribute to the continuous improvement of all laboratories. Some preliminary results of a questionnaire concerning the present status of accreditation in the countries of the European Union are presented. It shows quite diversity in the accreditation process in relation to the interval between assessment visits and the frequency of surveillance visits. The Working Group on Accreditation of the EC4 will use the input of this questionnaire and the content of some ILAC and EA guidelines, to offer Essential Criteria on some of these aspects. .
ISO 15189:2003: A practical tool for the management of quality in the medical laboratory
Authors: Burnett David
Published: August 2005

The requirements of ISO 15189:2003 are discussed in the context of a process and outcome based quality management model in which the user?s needs are the central focus. The requirements of ISO 15189:2003 are examined in terms of organization and a quality management system and stress the importance of evidence, document control and control of records and clinical material. Examples are provided from the areas of resource management, pre examination, examination and post examination processes. In the final section the importance of evaluation and continual improvement is presented in relation to internal audit and external assessment, non-conformity, corrective and preventative action and management review.
Protonation site for anilines in aqueous media
Authors: Pankratov Alexei , Uchaeva Inna
Published: August 2005

By means of the PM3 method it has been shown that the protonation of 2-, 3 4-methoxyanilines, 4-methylthioaniline, 2-, 3-, 4-aminobenzoic acids, 2 3-, 4-nitroanilines in the gaseous phase proceeds via the amine nitrogen atom. The same result, attributed to the aqueous medium, was obtained for 4-methoxyaniline, 4-aminobenzoic acid and 4-nitroaniline.
The synthesis and characterization of nickel(II) and copper(II) complexes with the polydentate dialkyl dithiocarbamic acid ligand 3-dithiocarboxy-3-aza-5-aminopentanoate
Authors: Trifunovic Srecko , Markovic Zorica , Sladic Dusan , Andjelkovic Katarina , Sabo Tibor , Minic-Popovic Dragica
Published: August 2005

Square planar complexes of Ni(II) and Cu(II) with potassium 3-dithiocarboxy 3-aza-5-aminopentanoate have been prepared by direct synthesis. The obtained neutral complexes were characterized by elemental analysis, magnetic susceptibility measurements, infrared and electronic spectra. The thermal behaviour of both the Ni(II) and Cu(II) complexes, and the ligand itself was investigated by DSC and TG.
The effects of grinding on the physico-chemical characteristics of white sepiolite from Golesh
Authors: Vucelic Dusan , Simic Dana , Kovacevic Olgica , Dojcinovic Miroslava , Mitrovic Milan
Published: August 2005

The influence of grinding white sepiolites from the Magure-Golesh mine in Southern Serbia on their structure and on the rheological characteristics of their aqueous suspensions was investigated. Sepiolite samples of hard and soft consistency were ground in three different types of mills: a ball mill air-stream mill, and a colloid mill. The effect of grinding on the sepiolite samples was investigated by SEM, XRD, IR, TG and BET methods and by chemical analysis. Grinding generally resulted in the separation of the sepiolite fibers, and partial amorphization. In addition, grinding produced substantial changes in the apparent viscosity and rheological characteristics of dilute aqueous suspensions of sepiolite. It is concluded that the viscosities are especially affected by the type of grinding employed.
Application of potentiometric stripping analysis with constant inverse current in the analytic step for determining lead in glassware
Authors: Kalicanin Biljana , Marjanovic Nikola , Suturovic Zvonimir
Published: August 2005

The trace amounts of lead in extraction glassware products were determined by potentiometric stripping analysis with constant inverse current in the analytic step (PSA-iR), an electrochemical technique of high sensitivity and selectivity. This paper deals with an investigation which was directed to the effect of a great number of factors on the results of PSA-iR, of lead in glassware, such as the mercury time electrodeposition, the electrolysis potential, the solution stirring rate and the constant inverse current. Linearity of the lead analytical signal was achieved within the range of mass concentrations from 2.5 ?g/dm3 to 4.5 ?g/dm3.Adetection limit of 0.64 ?g/dm3 was obtained, with a reproducibility of 4.14 % expressed as the coefficient of variation. The analyses were carried out using a computerized stripping analyzer of domestic design and manufacture (Faculty of Technology, Novi Sad and "Elektrouniverzal", Leskovac). The accuracy of the method was confirmed by parallel analyses using flameless atomic absorption spectrophotometry as the reference method.
Mixed ligand complexes of alkaline earth metals: Part XII. Mg(II), Ca(II), Sr(II) and Ba(II) complexes with 5-chlorosalicylaldehyde and salicylaldehyde or hydroxyaromatic ketones
Authors: Prasad R.N. , Agrawal M. , Sharma M.
Published: August 2005

The reactions of alkaline earth metal chlorides with 5-chlorosalicylaldehyde and salicylaldehyde, 2-hydroxyacetophenone or 2-hydroxypropiophenone have been carried out in 1: 1: 1 mole ratio and the mixed ligand complexes of the type MLL?(H2O)2 (where M = Mg(II), Ca(II), Sr(II) and Ba(II),HL= 5-chlorosalicylaldehyde and HL?= salicylaldehyde, 2-hydroxyacetophenone or 2-hydroxypropiophenone) have been isolated. These complexes were characterized by TLC, conductance measurements, IR and 1H-NMR spectra.
Thermodynamic properties of cadmium compounds from quantum chemical evaluations
Authors: Pankratov Alexei
Published: August 2005

By the PM3 method, standard entropies, heats and free energies of formation for some cadmium compounds have been computed. Quantitative relationships Pexper vs, Ptheor, where P is any of the mentioned properties, have been established.
Reflection and structural characteristics of semi-bright and mirror bright nickel coatings
Authors: Nikolic Nebojsa , Rakocevic Zlatko , Djurovic Dejan , Popov Konstantin
Published: August 2005

The reflection and structural characteristics of the nickel coatings obtained in the presence of a basic brightening addition agent only, and of both a basic and top brightening addition agent are examined. It is shown that the nickel coating obtained in the presence of both a basic and top brightening addition agent fulfilled the conditions to be characterized as a mirror bright metal surface. The nickel coating obtained in the presence of a basic brightening addition agent only is characterized as a semi-bright metal surface.
Study of the stability of self-assembled N-vinylcarbazole monolayers to protect copper against corrosion
Authors: Wang Chun-Tao , Chen Shen-Hao , Ma Hou-Yi , Hua Lan , Wang Nai-Xing
Published: August 2005

N-Vinylcarbazole (NVC) monolayers were self-assembled on copper surfaces. The electrochemical properties of the copper surfaces modified by NVC self-assembled monolayers (SAMs) were investigated using polarization and electrochemical impedance spectroscopic (EIS) methods. The polarization measurements indicated that the NVCSAMs could reduce the rates of the anodic and cathodic reaction on the surface of copper electrodes in 0.5 mol dm-3 NaCl solution. The EIS results showed the NVC formed a closely packed film that was able to inhibit copper corrosion. X-Ray photoelectron spectroscopy (XPS) analysis of the copper samples and atomic adsorption analysis of the solution showed that the copper surfaces were covered by NVCSAMs, and the adsorption of NVC on the copper surfaces was accompanied with dissolution of Cu into the solution.
The effect of boron on the amount and type of carbides in chromium white irons
Authors: Tomovic-Petrovic Stanka , Markovic Srdjan , Zec Slavica
Published: August 2005

The effect of boron, in the amounts of 0.26, 0.39, and 0.59 wt.%, on the volume fraction and structure of carbides in Cr white irons was examined. It was demonstrated that the addition of boron can change the microstructural characteristics of white iron containing about 13 wt.% Cr. With increasing boron content, the volume fractions of M3C carbide increase, but the volume fracton of M7C3 carbide remains unchanged. The addition of boron tends to produce hard borides and/or borocarbides. It also prevents the formation of pearlite, which results in alloys possessing good wear resistance.
Kinetics of solanidine hydrolytic extraction from potato (Solanum tuberosum L) haulm solid-liquid systems
Authors: Nikolic Nada , Stankovic Mihajlo
Published: August 2005

Dried and milled haulm of potato (Solanum tuberosum L) was used as the solid phase. An ethanolic solution of hydrochloric acid mixed with chloroform in different volume ratios was the liquid phase. The aim of paper was to unite in a single step the processes of glycoalkaloids extraction from haulm, their hydrolysis to solanidine and the extraction of solanidine. This could make the procedure of obtaining solanidine faster and simpler. The best degree of solanidine hydrolytic extraction of 84.5% was achieved using 10% w/v hydrochloric acid in 96% vol. ethanol mixed with chloroform in a volume ratio of 2:3, after 120 min of hydrolytic extraction.
Kinetics of the zinc anodic dissolution reaction in near neutral EDTA solutions
Authors: Stankovic Slavka , Grgur Branimir , Krstajic Nedeljko , Vojnovic Milan
Published: August 2005

Polarization curves of the anodic dissolution reaction of zinc were determined in EDTA solutions of different total molar concentrations (0.05 0.10, 0.15 and 0.20 mol dm-3), the pH values of which were systematically varied (pH 3.0 ? 10.0). The Tafel slopes of the anodic polarization curves are close to 40 mV dec-1 at lower current densities (10-5 ? 5x10-4 A cm-2) while at higher current densities (5x10-4 ? 10-2 A cm-2) the slopes are in the range of 60 ? 120 mV dec-1. The order of the anodic reaction determined from the anodic polarization curves at lower current densities are: z+(H+) ?? 1/2 for pH < 8 and z+(H+) ??1 for pH > 8, while z+(H4Y) ??1 for all pH values of the examined EDTA solutions. On the basis of these results, two mechanisms of the zinc anodic dissolution reaction are proposed: at pH < 8 and at pH > 8. In both cases the relevant EDTA species directly participate as reactants in the anodic reaction. The dependences of the corrosion potential on pH and on total molar EDTA concentration indicate that the relevant EDTA species take part as reactants in both the cathodic (hydrogen evolution) and anodic (zinc dissolution) reactions of the zinc corrosion process.
Kinetic determination of ultramicro amounts of Cu(II) ion in solution
Authors: Grahovac Zora , Mitic Snezana , Pecev Emilija
Published: August 2005

A new kinetic method is described for the determination of ultramicro amounts of Cu(II) based on its catalytic effect on the oxidation of trisodium-2-hydroxy 1-(4-sulphonato-1-naphthylazo)naphthalene-6,8-disulphonato (red artificial color PONCEAU 4R) by hydrogen peroxide in borate buffer (B.B). The detection limit given by Perez-Bendito is 0.8 ng/cm3, but the detection limit that we experimentaly determined is 3.8 ng/cm3. The relative error ranges between 7.77 and 2.09%for the concentration interval 3.8 to 50.1 ng/cm3. Kinetic equations are proposed for the investigated process. The effects of certain foreign ions upon the reaction rate were determined for an assessment of the selectivity of the method. The method was applied for the determination of Cu(II) ions in samples of alloy.
Implicit-OR tiling of deoxyribozymes: Construction of molecular scale OR, NAND and four-input logic gates
Authors: Stojanovic Milan , Nikic Dragan , Stefanovic Darko
Published: August 2005

We recently reported the first complete set of molecular-scale logic gates based on deoxyribozymes. Here we report how we tile these logic gates and construct new logic elements: OR, NAND, and the first element with four inputs (i1^i5)V(i2^i6). Tiling of logic gates was achieved through a common substrate used for core deoxyribozyme; degradation of this substrate defines the output. This kind of connection between logic gates is an implicit- OR tiling, because it suffices that one componenet of the network is active for the whole network to give an output of 1.
Transition metal complexes with thiosemicarbazide-based ligand: Part 45 - Synthesis, crystal and molecular structure of [2, 6-diacetylpyridine bis(S-methylisothiosemicarbazonato)]diazide-iron(III)
Authors: Leovac Vukadin , Divjakovic Vladimir , Cesljevic Valerija , Fazlic Refik
Published: August 2005

The template reaction of a warm methanolic solution of FeCl3.6H2O S-methylisothiosemicarbazidehydroiodide and 2,6-diacetylpyridine in the presence of LiOAc and NaN3 yielded the high-spin complex [Fe(HL)(N3)2], were HL is the monoanion of the ligand 2,6-diacetylpyridine bis(S-methylisothiosemicarbazone). X-Ray analysis of the complex showed its pentagonal-bipyramidal configuration, with pentadenate (N5) HL in the equatorial plane and two monodentate azide groups in the axial positions. Crystal data are: monoclinic, P21/c,a=1.0263(2), b = 1.2525(2), c = 1.6660(3) nm, ?= 98.94?, V = 2.1154 nm3, Z = 4, ?x = 1.499 g cm-3, ?0 = 1.48 g cm-3, F(000) = 984, ?= 9.40 cm-1.
Synthesis and characterization of ether linkage containing bis-fluoran compounds
Authors: Patel Ritesh , Patel Jignesh , Patel Manish , Patel Rawan
Published: August 2005

2?-chloro-6?-diethylaminofluoran and 2?-chloro-3?-methyl-6?-diethylaminofluoran were reacted with various diphenols in dimethyl formamide in the presence of potassium carbonate to give the related bisfluoran compounds. All the synthesized derivatives were identified by conventional methods (IR, 1H-NMR), elemental analysis and UV-visible spectroscopy in organic solvent and 95 % acetic acid. All the fluoran compounds change their color in acidic media.
Synthesis and characterization of Co(II), Ni(II), Cu(II) and Zn(II) complexes with 3-salicylidenehydrazono-2-indolinone
Authors: Konstantinovic Sandra , Radovanovic Blaga , Cakic Zivojin , Vasic Vesna
Published: August 2005

Complexes of Co(II), Ni(II), Cu(II) and Zn(II) with 3-salicylidenehydrazono-2-indolinone were prepared. Their structure was established to be [MLCl].Cl by using elemental analysis and molar conductivity, as well as AA, FTIR, UV/VIS and 1H-NMR spectroscopic methods. The spectral studies indicated a square-planar geometry for the Ni(II) and Cu(II) complexes and a tetrahedral one for the Co(II) and Zn(II) complexes. The complexes were tested for antibacterial activity against Staphylococcus aureus, Enterococcus D, Proteus mirabilis, Escherichia coli, Bacillus anthracis, Pseudomonas aeruginosa and Candida albicans.
A microwave-catalyzed rapid, efficient and ecofriendly synthesis of substituted pyrazol-5-ones (Short communication)
Authors: Dabholkar Vijay , Gavande Rahul
Published: August 2005

A series of 1-(3,4-dihydro-3-oxo-2H-1,4-benzoxazine-2-carbonyl)-3-methyl-4-(substituted phenylhydrazono)-2-pyrazolin-5-ones have been synthesized by the reaction of 2H-3,4-dihydro-3-oxo-1,4-benzoxazine-2-carboxylic acid hydrazide with substituted acetoacetic ester derivatives using acetic acid as solvent under microwave irradiation (MWI), as well as by conventional methods. The reaction rate is enhanced tremendously and the yields are improved under MWI as compared to conventional methods.
Adsorption of inorganic anionic contaminants on surfactant modified minerals
Authors: Vujakovic Aleksandra , Dakovic Aleksandra , Lemic Jovan , Radosavljevic-Mihajlovic Ana , Tomasevic-Canovic Magdalena
Published: August 2005

Organo-mineral complexes were obtained by treatment of aluminosilicate minerals (zeolite, bentonite and diatomaceous earth) with a primary amine (oleylamine) and an alkyl ammonium salt (stearyldimethylbenzyl ammonium chloride). The modification of the zeolite surface was carried out in two steps. The first step was treatment of the zeolite with 2M HCl. This acid treatment of the zeolite increased its affinity for neutral molecules such as surface-active amines. The second step of the modification was the adsorption of oleylamine on the acid treated zeolite. Four types of organo-mineral complexes were prepared and their anion adsorption properties were compared to those of organo-zeolite. The adsorption of sulphate bichromate and dihydrogenphosphate anions on the organo-mineral complexes was investigated. The anion adsorption measurements showed that the most efficient adsorbent for anion water pollutants was the primary amine modified H+-form zeolite.
Comparisons of formic acid oxidation at supported Pt catalyst and at low-index Pt single crystal electrodes in sulfuric acid solution
Authors: Tripkovic Amalija , Popovic Ksenija , Lovic Jelena
Published: August 2005

The oxidation of formic acid was studied at supported Pt catalyst (47.5 wt%. Pt) and a low-index single crystal electrodes in sulfuric acid. The supported Pt catalyst was characterized by the TEM and HRTEM techniques. The mean Pt particle diameter, calculated from electrochemical measurements fits well with Pt particle size distribution determined by HRTEM. For the mean particle diameter the surface averaged distribution of low-index single crystal facets was established. Comparison of the activities obtained at Pt supported catalyst and low-index Pt single crystal electrodes revealed that Pt(111) plane is the most active in the potential region relevant for fuel cell applications.
Purification and partial characterization of superoxide dismutase from the thermophilic bacteria Thermothrix sp
Authors: Seatovic Svetlana , Gligic Ljubinka , Radulovic Zeljka , Jankov Ratko
Published: August 2005

Superoxide dismutase (SOD; EC 1.15.1.1), a high molecular weight component of the antioxidant defense system, provided promising results in the treatment of oxidative damage. Thermothrix sp., isolated from thermal spa water in Serbia, showed high superoxide dismutase activity. The SOD, from cell free extract, was purified to homogenity by ammonium sulfate precipitation, Sephadex G 75 gel filtration chromatography and QAE Sephadex ion exchange chromatography. The specific activity of the purified enzyme was 9191 U/mg. The purified enzyme was analyzed and partially characterized. SOD was localized in polyacrylamide gel by activity staining, based on the reduction of nitroblue tetrazolium (NBT) by superoxide. The enzyme molecular weight determined by gel chromatography is 37 kD. According to SDS PAGE it is composed of two subunits of equal size, joined by noncovalent interactions. The isoelectric point, assessed by isoelectric focusing is 5.3. The optimum pH for enzyme activity was in the range of 8 to 10. The optimum temperature for SOD activity was 60 ?C. After one hour of incubation at 40, 50 and 60 ?C the SOD activity increases, but at 80 ?C, the SOD is denaturated. After 24 hours of incubation at 25 ?C SO Dactivity only slightly decreases.
Alkylation of N-substituted 2-phenylacetamides: Benzylation of N-(4-chlorophenyl)-2-phenylacetamide
Authors: Mijin Dusan , Jankovic Vida , Petrovic Slobodan
Published: August 2005

Benzylation of N-(4-chlorophenyl)-2-phenylacetamidewith benzyl chloride in the presence of powdered potassium hydroxide under various reaction conditions was performed in order to establish the possible reaction products. Different temperatures and ratios of reactants and solvents were used. The reactions were also carried out in the presence of different phase-transfer catalysts in toluene as a solvent. The formation of the reaction products was followed using gas chromatography. On the basis of the obtained results, the reactivity and the orientation in the alkylation reaction of the investigated amide is discussed.
Photochemical and Beckmann rearrangement of (Z)-cholest-4-en-6-one oxime
Authors: Krstic Natalija , Bjelakovic Mira , Dabovic Milan , Lorenc Ljubinka , Pavlovic Vladimir
Published: August 2005

Beckmann rearrangement of (Z)-cholest-4-en-6-one oxime (4) (prepared in 4 steps starting from cholest-5-en-3?-ol ?1)) with thionyl chloride in dioxane solution afforded an enamide-type lactam, i.e. 7-aza-B-homocholest-4-en-6-one (6) as a single product. Photoreaction of the same compound in methanol or benzene-acetic acid solution gave a mixture of products, with the formation of the parent ketone 3 and the occurrence of Z/E isomerization, while the lactam 6 was obtained only when the reaction was performed in methanol and then in very low yield (7%).
Change of refractive indices in ternary mixtures containing chlorobenzene + n-hexane + (n-heptane or n-octane) at 298.15 K
Authors: Touriño A. , Hervello M. , Moreno V. , Marino G. , Iglesias M.
Published: August 2005

The refractive indices of ternary mixtures of chlorobenzene + n-hexane (n-heptane or n-octane) have been measured at 298.15 K and at atmospheric pressure over the whole composition diagram. Parameters of polynomial equations which represent the composition dependence of physical and derived properties are gathered. The experimental refractive indices and the ternary derived properties are compared with the data obtained using several predictive semi-empirical models. The use of the Soave?Redlich?Kwong (SRK) and the Peng?Robinson (PR) cubic equations of state with the Van der Waals one-fluid mixing rule, which incorporate different combining rules to predict refractive indices on mixing, are tested against the measured results, good agrement being obtained.
Phonon anomalies in optical spectra of LnNbO3 single crystals
Authors: Golubovic Aleksandar , Gajic Rados , Hinic Ivana , Valcic Andreja
Published: August 2005

LiNbO3 single crystals were grown by the Czochralski technique in an air atmosphere. The critical crystal diameter Dc = 1.5 cm and the critical rate of rotation ?c=35 rpm were calculated by equations from the hydrodynamics of the melt. The domain inversion was carried out at 1430 K using a 3.75 V/cm electric field for 10 min. The obtained crystals were cut, polished and etched to determine the presence of dislocations and single domain structures. The optical properties were studied by infrared and Raman spectroscopy as a function of temperature. With decreasing temperature, an atypical behaviour of the phonon modes could be seen in the ferroelectrics LiNbO3. The obtained results are discussed and compared with published data.
Variation in the chemical constituents of soybean due to the industrial pollution
Authors: Patel Devendra , Kumar Ranjan , Prasad Satgur
Published: August 2005

The two varieties of soybean (Soybean Bragg and Soybean JS-71-05) were collected from an industrial site (IS) and from a non-industrial site (NIS) for the study of their chemical composition and fatty acids profiles by gas liquid chromatography (GLC). These studies revealed large changes in the major and minor fatty acids of the soybean seeds due to the effect of chemical pollutants. There was a significant decrease in the amounts of major and minor fatty acids, such as myristic acid (14:0), palmitic acid (16:0) stearic acid (18:0), oleic acid (18:1), linoleic acid (18:2), and linolenic acid (18:3), in the seeds from industrial site. The changes in the chemical composition due to chemical pollutants showed mixed results.
Alkylation of N-substituted-2-phenylacetamides
Authors: Mijin Dusan , Misic-Vukovic Milica , Petrovic Slobodan
Published: August 2005

Various N-substituted phenylacetamides were alkylated using different alkylating agents under neutral and basic conditions. Reactions were performed at different reaction temperatures and in various solvents. Also, a number of various catalysts were used including phase-transfer catalysts. Reactions were followed using GC or GC-MS technique and the presence as well as the yields of the alkylation products were established. Generally, the best yield and high selectivity in the studied reactions were achieved under basic conditions where in the certain cases some products, mostly N-product were obtained solely in quantitative yields.
Protein covalent modification of biologically active quinones
Authors: Sladic Dusan , Novakovic Irena , Vujcic Zoran , Bozic Tatjana , Bozic Natasa , Milic Dragan , Solaja Bogdan , Gasic Miroslav
Published: August 2005

The avarone/avarol quinone/hydroquinone couple shows considerable antitumor activity. In this work, covalent modification of ?-lactoglobulin by avarone and its derivatives as well as by the synthetic steroidal quinone 2,5(10)-estradiene- 1,4,17-trione and its derivatives were studied. The techniques for studying chemical modification of ?-lactoglobulin by quinones were: UV/Vis spectrophotometry, SDS PAGE and isoelectrofocusing. SDS PAGE results suggest that polymerization of the protein occurs. It could be seen that the protein of 18 kD gives the bands of 20 kD, 36 kD, 40 kD, 45 kD, 64 kD and 128 kD depending on modification agent. The shift of the pI of the protein (5.4) upon modification toward lower values (from pI 5.0 to 5.3) indicated that lysine amino groups are the principal site of the reaction of ?-lactoglobulin with the quinones.
Pb1-xMnxTe single crystals and their structural properties
Authors: Golubovic Aleksandar , Nikolic Slobodanka , Djuric Stevan , Romcevic Nebojsa
Published: August 2005

Pb1-xMnxTe crystals were grown by the vertical Bridgman method. Their structural properties were observed both by optical microscopy after chemical polishing and ething, and by X-ray powder diffraction analysis. A solution of 5 vol. % Br2 in HBr at room temperatur, for an exposure of 2 min was determined for chemical polishing. Asolution of 20 g KOH in 1 ml H2O2, 2 ml glycerol (C3H8O3), and 20 ml H2O at room temperature for an exposure for 6 min was found to be a suitable etching solution. The obtained results are discussed and compared with published data.
The growth of ruby single crystals
Authors: Golubovic Aleksandar , Nikolic Slobodanka , Djuric Stevan , Valcic Andreja
Published: August 2005

Ruby (Cr:Al2O3) single crystals were grown by the Czochralski technique in an argon atmosphere. The critical crystal diameter dc = 1.0 cm and the critical rate of rotation ?c = 20 rpm were calculated by equations of the hydrodynamics of the melt. The rate of crystal growth was experimentally obtained to be 2.7 mm/h. For chemical polishing, conc. H3PO4 at 593 K for an exposure of 3 hours was determined. Conc. H3PO4 at 523 K for an exposure of 3 h was found to be a suitable etching solution. The lattice parameters a = 0.47627(6) nm and c = 1.301(1) nm were determined by X-ray powder diffraction. The obtained results are discussed and compared with published data.
Linear and nonlinear luminescence properties of thiophene based materials
Authors: Ping L.U. , Xia Ming
Published: August 2005

Three new thiophene based organic luminescence compounds, i.e., 2,5-bis(4?-N,N-dimethylaminostyryl) thiophene (BMST), 2,5-bis(4?-N,N-diethylaminostyryl)thiophene (BEST) and 2,5-bis(4?-N-cyclobutylaminostyryl)thiophene (BBST), were synthesized. All of their measured single-photon excited fluorescence (SPEF) are located in the range of ? 530 nm with quantum yields of around 40 %, and the corresponding lifetime was ? 1 ns. The examined compounds show strong solvatochromism in their SPEF spectra. Excited by a fs laser at 800 nm, a strong up-converted fluorescence of the examined compounds was detected. The profile of two-proton excited fluorescence (TPEF) was similar to that of SPEF. The two-photon absorption (TPA) cross sections of the compounds were determined by the TPEF method. All the compounds showed large TPA cross sections. Hence these thiophene derivatives may have good TPA properties.
Inhibition effects in the partial oxidation of cyclohexane on polymer supported Co(II) catalysts
Authors: Loncarevic Davor , Cupic Zeljko , Odovic Maja
Published: August 2005

Polymer supported catalysts with different contents of metal ions where synthesized by wet impregnation of the degassed support from ethanolic solutions of cobalt(II) nitrate. Amacroreticular copolymer of poly-4-vinylpyridine with divinylbenzene was used as the support. The prepared catalysts were tested in the partial oxidation of cyclohexane to cyclohexanol and cyclohexanone. Activity tests were performed in a stainless steel, laboratory scale, stirred autoclave, in the semi batch regime under isothermal and non-isothermal conditions. Isothermal experiments where performed at 170 ?C for 120 min. In the non-isothermal conditions. isothermal experiments where performed at 170 ?C for 120 min. In the non-isothermal experiments, a constant heating rate of 0.3 degree/min was used in the range between 110 ?C and 170 ?C. Non-linear, least-squares analysis with the simplex optimization method and numerical simulation of the reaction model in each iterative step was used for the kinetic characterization of the process in a non-stationary, semi-batch regime. Apparent rate constants were obtained as an invariant measure of the catalytic system. Anon-linear effect of the content of metal ions on the reaction rate and on the ratio of the yield of the products was observed, which is attributed to a complex interactions between the reaction medium and the heterogeneous catalyst, including a catalyst-inhibition effect.
The spectrophotometric determination of boron in tourmalines
Authors: Jaksic Ljiljana
Published: August 2005

A procedure for the spectrophotometric determination of macro amounts of boron in tourmaline with azomethine H is described. The used tourmaline concentrate was obtained by magnetic separation and heavy-liquids purification of the schorl zone of pegmatite or granite aplite. The samples of tourmaline were decomposed by fusion with anhydrous sodium carbonate and taken up in dilute hydrochloric acid. The interfering effects of iron and aluminium were eliminated by masking with an EDTA - NTA solution. After pH adjustment, the boron was reacted with azomethine H and the absorbance of the obtained coloured complex was measured at 415 nm. The results are compared with those obtained by other procedures. The relative error of the determination was less than 3 %.
Influence of Mie scattering on nanoparticles with different particle sizes and shapes: Photometry and analytical ultracentrifugation with absorption optics
Authors: Lechner M.D.
Published: August 2005

Nanoparticles are used in large quantities for very different applications. A precise determination of the diameter and the particle size distribution which is responsible for the application properties is therefore essential. Reliable methods for measuring the above mentioned quantities are photometric measurements and analytical ultracentrifugation with an UV optics detector. Both methods are ruled by the Mie effect, that is scattering and absorption of the particles as function of the diameter, the wavelength, and the shape of the particles. The extinction coefficients ?=?/c for spheres, rods, and core shell particles have been calculated and plotted over a wide range of the size parameter ?d/?. Two examples for multimodal latex particles and core shell particles have been given and demonstrate the applicability of the method.
Topology and stability of conjugated hydrocarbons: The dependence of total π-electron energy on molecular topology
Authors: Gutman Ivan
Published: August 2005

In spite of the fact that research on the mathematical properties of the total ?-electron energy E (as computed by means of the H?ckel molecular orbital approximation) started already in the 1940s, many results in this area have been obtained also in the newest times. In 1978 this author published in this journal a review on E. The present article is another review on E, summarizing the progress in the theory of E, achieved since then.
The effects of alkyd/melamine resin ratio and curing temperature on the properties of the coatings
Authors: Radicevic Radmila , Budinski-Simendic Jaroslava
Published: August 2005

Abstract: Synthetic resins are used as binders in protective coatings. An alkyd/melamine resin mixture is the usual composition for the preparation of a coating called "baking enamel" cured through functional groups of resins. The effects of the alkyd/butylated melamine resin ratio (from 85/15 to 70/30) and curing temperature (from 100 ?C to 160 ?C) on the crosslinking and properties of the coating are presented in this paper. The degree of curing was determined by differential scanning calorimetry. These data were used for the estimation of the degree of crosslinking. The hardness, elasticity impact resistance, degree of adherence and gloss were also determined. Optimal coating properties could be achieved with an alkyd/melamine resin ratio of 75/25, a curing temperature of 130 ?C and a curing time of 30 min.
Socioeconomic and Geographic Differences in Mammography Trends Following the 2009 USPSTF Policy Update
Authors: Semprini Jason , Saulsberry Loren , Olopade Olufunmilayo I.
Published: February 2025

Importance

In 2024, the US Preventive Services Task Force (USPSTF) reversed a 2009 policy recommending only females aged 50 to 74 years complete a biennial mammogram. Understanding whether females facing heterogeneous breast cancer risks responded to the 2009 guidance may illuminate how they may respond to the latest policy update.

Objective

To evaluate whether the 2009 policy was associated with changes in mammography screening in females no longer recommended to complete a biennial mammogram and whether these changes varied by factors associated with breast cancer risk.

Design, Setting, and Participants

The difference-in-differences design compared biennial mammogram trends in the exposed groups (aged 40-49 and ≥75 years) with trends of the unexposed groups (aged 50-64 and 65-74 years), before and after the 2009 update. Population-based, repeated cross-sectional survey data came from the Behavioral Risk Factor Surveillance System (BRFSS) biennial cancer screening module (2000-2018). The sample was restricted to females between ages 40 and 84 years. Data were analyzed from March 1 to June 30, 2024.

Main Outcomes and Measures

The outcome was a binary variable indicating whether the respondent reported a mammogram in the past 2 years (biennial). After 2009, females aged 40 to 49 and 75 or older years were exposed to the policy update, as a complete biennial mammogram was recommended. Subgroup analyses included race and ethnicity, educational level, household income, smoking history, current binge drinking status, and state of residence.

Results

The sample included 1 594 834 females; 75% reported a biennial mammogram. In those aged 40 to 49 years, the USPSTF update was associated with a 1.1 percentage-point (95% CI, −1.8% to −0.3 percentage points) decrease in the probability of a biennial mammogram, with the largest decreases in the non-Hispanic Black population (−3.0 percentage points; 95% CI, −5.5% to −0.5 percentage points). In the aged 75 years or older group, the USPSTF update was associated with a 4.8 percentage-point decrease (95% CI, −6.3% to −3.5 percentage points) in the probability of a biennial mammogram, with significant heterogeneity by race and ethnicity, binge drinking status, and state residence.

Conclusions and Relevance

In this study, socioeconomic factors were associated with differences in how females responded to the 2009 USPSTF mammography recommendation. Whether the 2024 update considered such differences is unclear. These findings suggest that including risk assessment into future USPSTF policy updates may improve adoption of risk-reducing interventions and shorten the time to diagnosis and treatment for high-risk patients.
Decoding multicellular interaction networks–a new horizon in tumor microenvironment research
Authors: Balaban Roi , Cohen Merav
Published: February 2025

The tumor microenvironment (TME) milieu directs a plethora of tumor‐modulating functions. Recent years have seen pivotal breakthroughs in our understanding of the TME's role in tumor initiation and progression, with tangible clinical applications. Individual components of the TME exert their function predominantly by cell–cell crosstalk, both in the form of physical interaction and secreted factors. Notably, different spatial niches represent exclusive signaling hubs in the TME, propagating pro‐ or antitumoral functions. The exploration of these interactions has been vastly facilitated by novel molecular technologies, each of which provides a different perspective on this intricate intercellular communication network. Together, these complementary methods paint a detailed, high‐resolution map of the TME's interaction landscape. In this viewpoint, we explore how cellular interactions can unlock a new level of understanding of TME complexity, and discuss the promises and challenges of characterizing tumors based on their cellular interaction footprint.
High‐precision localization of radiation isocenter using Winston‐Lutz test: Impact of collimator angle, phantom position, and field size
Authors: Du Weiliang
Published: February 2025

Purpose

This study aimed to evaluate the impact of collimator angle, ball bearing (BB) phantom position, and field size on the accuracy of Winston‐Lutz (WL) test–derived radiation isocenters.

Methods

WL tests were performed on four TrueBeam linear accelerators. Fifty‐six images (eight gantry angles multiplied by seven collimator angles) were acquired for each WL test. Images with different sets of collimator angles were used to compute the radiation isocenters. The resulting radiation isocenters were correlated with the collimator angles. Then, the BB position and radiation field size were varied for the subsequent WL tests. The calculated BB shifts were compared with the known shifts, and the radiation isocenters were compared between different field sizes.

Results

The use of a single collimator angle led to errors of as much as 0.4 mm in the calculated radiation isocenters. Systematic differences were observed between the radiation isocenters derived with collimator angle 0° and those derived with 90° and/or 270°. A commonly used opposing collimator angle pair, 90° and 270°, resulted in a vertical 0.1 mm offset of the radiation isocenters toward the ceiling. Oblique opposite or mixed collimator angles yielded radiation isocenter errors less than 0.1 mm. The BB shifts derived from WL tests were less than 0.1 mm from the known shifts. The radiation isocenters varied by less than 0.1 mm between field sizes ranging from 2 × 2 cm2 to 20 × 20 cm2.

Conclusions

Oblique opposing collimator angle pairs should be considered to minimize errors in localizing radiation isocenters. Uncertainty in BB positioning could be eliminated if the BB is used as a static reference point in space. The field size had no significant effect on the radiation isocenters. With careful design of WL test parameters and image processing, it is possible to achieve a precision of 0.1 mm in localizing radiation isocenters using WL tests.
Multimaterial Bonding of Additively Manufactured Carbon Fiber‐Reinforced Thermoplastics/64 Titanium
Authors: Shirasu Keiichi , Mizuno Takeru , Tohmyoh Hironori
Published: February 2025

The integration of lightweight materials in hybrid structures is critical for achieving energy efficiency in automotive and aerospace industries. This study presents a novel method for directly bonding carbon‐fiber‐reinforced thermoplastics to Ti6Al4V titanium alloy (64Ti) substrates using fused filament fabrication 3D printing. The technique involves 3D printing short carbon fiber‐reinforced polyamide 6 onto sandblasted 64Ti substrates, heated via a hot plate integrated into the 3D printer. Lap‐shear tests reveal that adhesion strength improves with increased fusion time, achieving a maximum shear stress of 27.3 ± 2.2 MPa for 60 min welding. Finite element analysis demonstrates stress concentrations at the adhesion edges and highlights the formation of a fracture process zone with localized plastic deformation and microcrack generation. Additionally, the feasibility of fabricating 3D structures and integrating continuous carbon fiber‐reinforced thermoplastics onto 64Ti substrates is demonstrated. This study advances hybrid material joining techniques by providing a cost‐effective, scalable method for achieving robust metal‐composite bonds suitable for structural applications.
Biomimetic Design of Photothermal/Electrothermal Fabric Composed of Carbon‐Core/Nanorod‐Array‐Shell Fibers for Efficient All‐Weather Seawater Evaporation
Authors: Li Xiaolong , Chen Yonghang , Zhu Bo , Salimi Mohsen , Zhang Lisha , Amidpour Majid , Zhu Meifang , Chen Zhigang
Published: February 2025

Sunlight/electricity‐driven thermal evaporation has been demonstrated as a promising strategy to obtain distilled water from seawater, but their practical applications are still limited by unsatisfactory photoabsorption and serious water‐electrolysis during photothermal/electrothermal evaporation. Inspired by Paradisaeidae's feather and electric kettle, the biomimetic design of photothermal/electrothermal fabrics for realizing all‐weather evaporation is reported. The fabrics are composed of fiber bundles with carbon fiber (CF) as the core and polypyrrole‐decorated TiO2 nanorod‐array as a shell. Such CF/TiO2/PPy fabric exhibits broad‐spectral (280–2500 nm) photoabsorption with an efficiency of 95.5% due to the light‐trapping effect, and it shows an evaporation rate (2.2 kg m−2 h−1) under 1 sun. Additionally, CF/TiO2/PPy fabric demonstrates good electrothermal performance with suppressed water‐electrolysis owing to the conductivity of CF and shielding effect of the nanorod‐array‐shell, resulting in high evaporation rate of 7.9 kg m−2 h−1 under 3 V. Importantly, by the combined effects of 1 sun and 3 V, CF/TiO2/PPy fabric achieves an exciting evaporation rate of 9.1 kg m−2 h−1, even without solid‐salt accumulation in the long‐term evaporation process (10 h), benefiting from efficient photo/electrothermal conversion and sufficient water‐supplementation from thermosiphon effect. Thus, the present biomimetic design of photothermal/electrothermal fabric supplies a new path to realize efficient all‐weather seawater evaporation.
A Water State Manipulation Strategy for Ultra‐Stiff Yet Highly Sensitive Hydrogels
Authors: Zhang Yunfei , Ye Shuling , Yang Yaolong , He Rubin , Lin Jun , Hong Zeyang , Yuan Conghui , Dai Lizong
Published: February 2025

Hydrogels in water or aqueous solutions swell or shrink unidirectionally until reaching an equilibrium state, which has been extensively studied through both experimental analysis and theoretical prediction. In this work, an unexpected concurrent swelling and deswelling behavior of hydrogels is reported, which manipulates the water state in the polymer networks. The osmotic pressure‐driven rapid deswelling and the ionic electrostatic repulsion‐driven slow swelling of hydrogels occur simultaneously, affording double‐layered polyacrylamide (PAM) hydrogels, in which the rigid inner layer does not contains free water, while the soft outer layer comprises both bound and free water. The PAM hydrogels show uniaxial tensile fracture strengths and Young's moduli up to 104.2 MPa and 2.4 GPa, respectively, outperforming various polymeric and biological structural materials. This strategy is applicable to the general molding and three‐dimensional (3D) printing techniques, providing wide possibilities for engineering applications. Such strong and rigid hydrogels can simultaneously serve as structural materials for load‐bearing and act as functional materials for super‐stress (25 to 6000 N) and highly adaptable tactile sensing. These findings enrich the hydrogel swell/deswelling theory and broaden the engineering applications of hydrogels as structural materials.
Sequential Stimuli‐Response System of Eu‐MOF Isomers
Authors: Fan Wenwen , Cheng Yi , He Runying , Feng Mingxia , Zhou Qian , Ma Xiurong , Liu Yanxiong , Shi Yonggang , Zheng Liyan , Cao Qiue
Published: February 2025

Multiple stimuli‐responsive materials hold excellent potential for the next generation smart materials owing to their unique response to external stimuli, providing a powerful impetus for the development of intelligent optical devices. The stimuli‐responsive behavior of common multiple stimuli‐responsive materials are independent of each other, causing the lack of multiplicity and identification for information technology, which is easy to decode. Herein, QIPA‐Eu‐1 and QIPA‐Eu‐2 isomers were prepared from QIPA and EuCl3·6H2O in different solvent thermal conditions for building sequential stimuli‐response (SSR) system. Solvent‐driven structural transformations of the isomers into QIPA‐Eu‐3 occurred, along with color change and fluorescence emission variation ascribed to the generation of QIPA aggregates. Furthermore, QIPA‐Eu‐3 displayed excellent photochromic behaviors. Combining theoretical calculation with well‐defined experiments to reveal the mechanism, it was found that light drove the change in the dihedral angles between the quinoline nucleus and adjacent benzene rings in QIPA aggregates. Finally, on the basis of sequential stimuli‐induced stepwise responsive behavior of QIPA‐Eu‐1, the sequential logic gate and time‐dependent fluorescence dynamic anti‐counterfeiting pattern were successfully constructed. This study provided a new perspective for design and construction of SSR system, which showed promising potential in the fields of data transmission and information encryption.