bluuebunny/crossref_metadata_2025 huggingface dataset:
Q-conjugacy character table for the non-rigid group of 2,3-dimethylbutane
Authors: Darafsheh Reza , Moghani Ali
Published: February 2009

Maturated and unmaturated groups were introduced by the Japanese chemist Shinsaku Fujita, who used them in the markaracter table and the Q-conjugacy character table of a finite group. He then applied his results in this area of research to enumerate isomers of molecules. Using the non-rigid group theory, it was shown by the second author that the full non-rigid (f-NRG) group of 2,3- -dimethylbutane is isomorphic to the group (Z3?Z3?Z3?Z3):Z2 of order 162 with 54 conjugacy classes. Here (Z3?Z3?Z3?Z3):Z2 denotes the semi direct product of four copies of Z3 by Z2, where Zn is a cyclic group of order n. In this paper, it is shown with the GAP program that this group has 30 dominant classes (similarly, Q-conjugacy characters) and that 24 of them are unmatured (similarly, Q-conjugacy characters such that they are the sum of two irreducible characters). Then, the Q-conjugacy character table of the unmatured full non-rigid group 2,3-dimethylbutane is derived.
Primary and secondary dendrite spacing of Ni-based superalloy single crystals
Authors: Kostic Slobodanka , Golubovic Aleksandar , Valcic Andreja
Published: February 2009

Ni-based superalloy single crystals were grown by different methods (gradient method and Bridgman technique with spontaneous nucleation and with seed). In all crystal growth experiments using the Bridgman technique, the temperature gradient along the vertical furnace axes was constant (G = 33.5 ?C/cm). The obtained single crystals were cut, mechanical and chemical polished, and chemically etched. Using a metallographic microscope, the spacing of the primary and secondary dendrites was investigated. The dendrite arm spacing (DAS) was determined using a Quantimet 500 MC. The obtained results are discussed and compared with published data.
Specific transformations of mineral forms of nitrogen in acid soils
Authors: Kresovic Mirjana , Jakovljevic Miodrag , Blagojevic Srdjan , Maksimovic Srboljub
Published: February 2009

Investigations were performed on soils of different acidity, ranging in the pH interval 4.65-5.80 (in water). Changes of the mineral nitrogen forms in the examined soils were studied by applying short-term incubation experiments performed under aerobic conditions, with a humidity of 30 % and a temperature of 20?C, both with and without the addition of 100 and 300 ppm NH4-N. The results of the incubation experiments showed that retarded nitrification was present in all the examined soils. Increased and toxic quantities of nitrites (35.7 ppm) were formed during the incubation, which remained in the soil solution for several days, and even weeks, in spite of favorable conditions of moisture, aeration and temperature for the development of the process of chemoautotrophic nitrification. Decelerated chemoautotrophic nitrification was the source of the occurrence of nitrite in the examined less acid soil (soil 1), while in soils of higher acidity (soils 2 and 3) after addition of 100 and 300 ppm NH4-N, nitrite occurred due to chemical denitrification (chemodenitrification). Nitrites formed in the process of chemodenitrification underwent spontaneous chemical oxidation resulting in nitrate formation (chemical nitrification). The content of mineral nitrogen (NH4 + NO3 + NO2-N) decreased during the incubation period, proving gaseous losses from the examined soils. Application of lower doses of nitrogen fertilizers could decrease nitrogen losses by denitrification as well as the occurrence of nitrite in toxic quantities in the investigated pseudogley soil.
Mortality from heart attack in Belgrade population during the period 1990-2004
Authors: Ratkov Isidora , Sipetic Sandra , Vlajinac Hristina , Sekeres Bojan
Published: February 2009

INTRODUCTION In most countries, cardiovascular diseases are the leading disorders, with ischemic heart diseases being the leading cause of death. According to WHO data, every year about 17 million people die of cardiovascular diseases, which is 30% of all deaths. Ischemic heart diseases contribute from one-third to one-half of all deaths due to cardiovascular diseases. Three point eight million men and 3.4 million women in the world die every year from ischemic heart diseases, and in Europe about 2 million. The highest mortality rate from ischemic heart diseases occurs in India, China and Russia. OBJECTIVE The aim of this descriptive epidemiological study was to determine heart attack mortality in Belgrade population during the period 1990-2004. METHOD In the study, we conducted investigation of Belgrade population during the period 1990-2004. Mortality data were obtained from the city institution for statistics. The mortality rates were calculated based on the total Belgrade population obtained from the mean values for the last two register years (1991 and 2002). The mortality rates were standardized using the direct method of standardization according to the world (Segi) standard population. RESULTS In the Belgrade population during the period 1990-2004, the participation of mortality rate due to heart attack among deaths from cardiovascular diseases was 17% in males and 10% in females. In Belgrade male population, mean standardized mortality rates (per 100,000 habitants) were 50.5 for heart attack, 8.3 for chronic ischemic heart diseases and 4.6 for angina pectoris, while in females the rates were 30.8, 6.7 and 4.2, respectively. Mortality from ischemic heart diseases and from heart attack was higher in males than in females. During the studied 15-year period, on average 755 males and 483 females died due to heart attack every year. Mean standardized mortality rates per 100,000 habitants were 50.0 in male and 31.1 in female population. Males died 1.6 times more frequently from heart attack than females. During the studied period, mean standardized mortality rates from heart attack, in the population aged over 30 increased with age both in male and female population. However, males tended to die from heart attack at an earlier age than females, with death rates for males approximately the same as those for women who were 10 years older. CONCLUSION In Belgrade during the period from 1990-2004, we found that there was an increasing trend in mortality rate due to cardiovascular diseases, while the trend of mortality rate from heart attack was constant with insignificant oscillations.
The prevalence of childhood obesity in a sample of schoolchildren in Belgrade
Authors: Kisic-Tepavcevic Darija , Jovanovic Natasa , Kisic Vesna , Nalic Dragana , Repcic Mira , Popovic Aleksandra , Pekmezovic Tatjana
Published: February 2009

INTRODUCTION Obesity in children has become a global epidemic with many health and social consequences that often continue into adulthood. According to the International Obesity Task Force report from 2005, Serbia has had one of the most rapidly increasing trends in the prevalence of childhood obesity during the last 10 years. OBJECTIVE The aim of the study was to estimate the prevalence of childhood obesity in a sample of schoolchildren in Belgrade and to investigate the correlation between child obesity and the presence of selected diseases. METHOD The study comprised of 854 pupils from two primary schools in Belgrade. The anthropometric data, as well as the data on the presence of selected diseases were obtained from medical records of regular health check-ups in the period from 2006-2007. The classification of childhood obesity was done according to the WHO percentiles reference data for obesity and overweight in children. Statistical analyses included ?2 test and correlation analysis. RESULTS In our sample of schoolchildren, the prevalence of obesity was 30.7%. The following diseases were present among the pupils: spinal deformities 192 (22.5%), chest wall deformities 90 (10.5%) and foot deformities 226 (26.5%). Statistically significant correlation was registered between child obesity and the presence of spinal (?=0.192; p=0.001) and foot deformities (?=0.099; p=0.049). Chest wall deformities were more frequent in the group of children with normal weight compared with the obese group (?2=0.206; p=0.052). Statistically significant correlation was registered between childhood obesity and the presence of hypertension (?=0.261; p=0.001). Regular physical activity was in correlation with the absence of childhood obesity (?=-0.093; p=0.055). CONCLUSIONS In our sample of Belgrade schoolchildren, we detected a high prevalence of obesity. Furthermore, a significant correlation between childhood obesity and the presence of hypertension, spinal deformities and foot deformities were also observed.
Economic aspects of hospital treated pneumococcal pneumonia and the results of Pneumo 23 vaccine use in Serbia
Authors: Adzic Tatjana , Rosic Ilija , Jovanovic Dragana , Medic-Stojanac Snezana
Published: February 2009

INTRODUCTION In Serbia, there is a significant number of persons suffering of pneumococcal pneumonia. Persons aged 65 years or older, immunocompromised patients, patients with co-morbidities, such as chronic obstructive lung disease and congestive heart failure, are at the highest risk for developing pneumococcal pneumonia. Most of the patients are treated empirically, although it is often overlooked that Streptococcus pneumoniae can be resistant to the used antibiotics. The treatment costs of such inpatients and outpatients are very high. In Serbia, immunization of persons at risk to develop the diseases caused by Streptococcus pneumoniae is carried out using pneumococcus polysaccharide vaccine according to clinical indications. The exact number of immunized persons and the total number of registered patients are still unknown, but it is certain of being unjustifiably low. OBJECTIVE The goal of the study was to investigate, during a one-year period, the number and basic characteristics of persons hospitably treated for pneumonia, the type of cause of the infection, applied antibiotic medications, duration and costs of hospital treatment at the Institute for Lung Diseases and Tuberculosis of the Clinical Centre of Serbia in Belgrade. METHOD We retrospectively analyzed the medical records of patients with pneumonia treated at the Institute for Lung Diseases and Tuberculosis of the Clinical Centre of Serbia in Belgrade during 2006. RESULTS During the observed one-year period, 290 patients underwent hospital treatment, of whom the cause of the infection was confirmed in 116 (40%). The average duration of hospitalization was 12 days, with treatment cost of 32,031.74 RSD (402.42 EUR) per patient. The treatment cost per patient including general and intensive care was 18,290.01 RSD (229.78 EUR). The distribution cost of Pneumo 23 vaccine in Serbia, without purchase tax, was 746.90 RSD (9.38 EUR). CONCLUSION Pneumococcal pneumonia is a significant medical and economic problem for the healthcare system of Serbia. The use of antipneumococcal vaccination can be useful in decreasing the overall treatment costs related to pneumococcal infection.
Family characteristics of stuttering children
Authors: Simic-Ruzic Budimirka , Jovanovic Aleksandar
Published: February 2009

INTRODUCTION Stuttering is a functional impairment of speech, which is manifested by conscious, but nonintentionally interrupted, disharmonic and disrhythmic fluctuation of sound varying in frequency and intensity. Aetiology of this disorder has been conceived within the frame of theoretical models, which tend to connect genetic and epigenetic factors. OBJECTIVE The goal of the paper was to study the characteristics of the family functioning of stuttering children in comparison to the family functioning of children without speech disorder, which confirmed the justification of the introduction of family orientated therapeutic interventions into the therapy spectrum of child stuttering. METHOD Seventy-nine nucleus families of 3 to 6 year-old children were examined; of these, 39 families had stuttering children and 40 had children without speech disorder. The assessment of family characteristics was made using the Family Health Scale, an observer-rating scale which according to semistructured interview and operational criteria, measures 6 basic dimensions of family functioning: Emotional State, Communication, Borders, Alliances, Adaptability & Stability, Family Skills. A total score calculated from the basic dimensions, is considered as a global index of family health. RESULTS Families with stuttering children compared to families with children without speech disorder showed significantly lower scores in all the basic dimension of family functioning, as well as in the total score on the Family Health Scale. CONCLUSION Our research results have shown that stuttering children in comparison with children without speech disorder live in families with unfavorable emotional atmosphere, impaired communication and worse control over situational and developmental difficulties, which affect children's development and well-being. In the light of previous research, the application of family therapy modified according to the child's needs is now considered indispensable in the therapeutic approach to stuttering children. The assessment of family characteristics with special reference to the ability of parents to recognize specific needs of children with speech disorder and adequate interaction, as well as readiness of parents for therapeutic collaboration are the necessary elements in legal custody evaluations.
Parricide: Psychiatric morbidity
Authors: Dunjic Bojana , Maric Nadja , Jasovic-Gasic Miroslava , Dunjic Dusan
Published: February 2009

INTRODUCTION Parricide is defined as a murder of parents by their children; the patricide is murder of father, while matricide is murder of mother. This entity is classified as homicide, but it differs in the fact that victims are parents and the killers are their children. Mostly, it is associated with psychiatric morbidity. OBJECTIVE To describe sociodemographic and psychopathological characteristics of parricide committers and to analyze circumstances of parricide and psychiatric morbidity in order to achieve better recognition and prevention of risks. METHOD This retrospective study included all homicide autopsy records (1991-2005) performed at the Institute of Forensic Medicine, Medical School, University of Belgrade. For further analyses, all parricide records were selected out. The study analyzed all available parameters, which concerned parricide committers, victims and the act itself. Methods of descriptive statistics were used. RESULTS Between 1991 and 2005, there were 948 cases of homicide; of these, 3.5% were parricides. The committers of parricide were on average 31.2?11.9 years old, 87.8% were males, 60.6% with psychiatric symptoms most commonly with schizophrenia, alcohol dependence, personality disorder etc. Victims were on average 63.7?11.9 years old, 54.5% males, and 21.2% had a diagnosed mental illness. CONCLUSION Parricide is a rare kind of homicide accounting for 3% of all homicides. Committers are mostly unemployed males in early adulthood who have mental disorder. The phenomenon of parricide deserves a detailed analysis of the committer (individual bio-psycho-social profile) and the environ- mental factors (family, closely related circumstances) to enable a precise prediction of the act and prevention of the fatal outcome, which logically imposes the need of further studies.
Persistent sciatic artery: A case report
Authors: Sagic Dragan , Antonic Zelimir , Duvnjak Stevo , Peric Miodrag , Petrovic Branko , Ilijevski Nenad , Radak Djordje
Published: February 2009

INTRODUCTION The sciatic artery represents the earliest embryological blood supply to the lower extremity. It regresses after the 3rd month of embryologic development. The proximal part of the sciatic artery eventually persists as the inferior gluteal artery. Rarely, however, it persists into adulthood when it is frequently associated with numerous possible complications (aneurysm formation, embolism, nerve compression, rupture, thrombosis). CASE OUTLINE In March 1996, a 48-year-old male was admitted for angiography of the blood vessels of the right inferior extremity, before an elective orthopaedic procedure. Arteriography of the right leg was done in a usual manner through the right common femoral artery in order to get an angiogram of the popliteal trifurcation and crural arteries. However, on the first field we noticed a hypoplastic superficial femoral artery, as well as a huge persistent sciatic artery (PSA) originating from the internal iliac artery running distally and overlapping the deep femoral artery. There were no aneurysm and stenotic changes of PSA. CONCLUSION If clinical condition is stable, follow-ups at 12 months intervals should be done by means of ultrasound. The therapeutic decisions also depend on complete or incomplete PSA.
The effect of different irrigation techniques on the quality of cleaning of root canal walls
Authors: Pavlovic Violeta , Zivkovic Slavoljub
Published: February 2009

Aim: To evaluate the effect of irrigation techniques, i.e. different types of irrigation needles, on the quality of cleaning of root canal walls using scanning electron microscopy (SEM). Material and Method: The study was conducted on 16 extracted, single-rooted, human teeth. The samples were allocated to two experimental groups depending on the type of the irrigation needle. Conventional needles were used for the irrigation of Group I and laterally perforated ones for Group II. All root canals were instrumented using K files and the Step-back technique. During instrumentation, all samples were irrigated with 2.5 % sodium hypochlorite solution followed by final irrigation with 17 % EDTA for 1 min. After that, all samples were irrigated with 10 ml of distilled water. The roots were, then, sectioned longitudinally and middle one third of each root canal was analyzed using SEM. Quantitative analysis was based on criteria by H?lsmann et al. Results: The obtained results showed that the more efficient removal of debris and the smear layer was accomplished in the group of samples irrigated using laterally perforated needles than conventional needles. The difference between the investigated irrigation techniques were statistically significant (p<0.01). Conclusion: The use of laterally perforated needles for irrigation allows more efficient cleaning of root canal walls, i.e. the removal of debris and the smear layer.
The effect of a light source with reduced irradiance on the marginal seal in class V cavities
Authors: Gajic Natasa , Kojic Zeljka , Djeri Aleksandra , Arbutina Radmila , Trnic Zorica
Published: February 2009

Introduction: During composite polymerisation, material contraction occurs and leads to microgap formation. Various light sources are used in everyday dental practice for the polymerisation of composite restorations: conventional halogen, xenon, LED light curing units (LCUs) and argon lasers. Aim: The aim of this study was to analyze the effect of an LED LCU with reduced irradiance on the marginal seal of different composite restorations. Material and Method: The study was conducted on 40 extracted human teeth (intact and carious). Class V cavities were prepared on all teeth. Cavities were filled with either Filtek Supreme -3M (20 teeth) or Luksogal - Galenika (20 teeth) and polymerisation was done using an LED source with reduced irradiance (90 mW/cm2). Microleakage was tested using the dye penetration method with silver nitrate. Dye penetration was assessed using a stereo loupe with a microscale and x6 magnification. Results: The obtained results suggested that greater dye penetration occurred in samples restored with Luksogal. There was a statistically significant difference between occlusal (27.00) and gingival (36.90) margins (p<0.05). Dye penetration was observed in all intact and carious teeth restored with Filtek Supreme on both gingival and occlusal margins. A statistically significant difference was observed between gingival (22.90) and occlusal (15.50) margins (p<0.01). Conclusion: Microgaps were observed in all teeth irrespective of the type of composite material used for restoration.
The role and characteristics of a manager in the strategic transformation of the health care system
Authors: Gajic-Stevanovic Milena , Teodorovic Nevenka , Vuksa Ana , Zivkovic Slavoljub
Published: February 2009

Introduction: Global markets and competition, fast changes, the explosion of information technology, integration processes in international relations are some of the initial factors for changes in health care organizations and their management. Management represents an evolving new generic function of all organizations of social significance across the world. Managers in the health sector have exceptionally complex roles that require new skills and methods. The objective of this study is to analyze in grater detail, explain and describe the role and necessary skills of a health care manager in the strategic transformation of health care management. The modern health care manager can get the best results by strengthening human resources and meeting employees' personal needs in accordance with the global and specific goals of the health care institution. The manager is at the same time a mentor and a facilitator, putting to best use the forementioned transformation strategies whilst expending the resources carefully, strengthening the collective efforts, involving employees in the decision-making process and motivating teamwork and collective problem-solving.
Layered additive manufacturing in clinical medicine
Authors: Drstvensek Igor , Ihan-Hren Natasa , Strojnik Tadej , Pogacar Vojko , Zupancic Hartner , Sinkovic Andreja
Published: February 2009

The use of contemporary technologies of Computer Assisted Design (CAD), combined with latest rapid prototyping, tooling and manufacturing, with traditional CT scanning techniques and high medical skills are used as instruments for better diagnostic visualization, simulation of procedures and treatment of patients with craniofacial deformities. They also improve the overall performances of medical and nursing staff thus influencing the quality of medical service. Patients with congenital defects, orthognathic deformities, deformities after malignancy treatment or after craniofacial traumatic injuries of different severities are of particular interests due to both aesthetic and functional alterations. The paper presents two clinical cases - a patient with scull bone defect after brain hemorrhage and brain edema as well as a patient with hemifacial microsomia treated by surgery followed by implantation of titanium angular implant prepared by means of computer tomography scans, Computer Aided Design and Rapid Manufacturing technologies.
Spectral absorption of unpolarized light through nano-materials in the absence of a magnetic field
Authors: Luminosu I. , Popov D. , Zaharie I.
Published: February 2009

A study of optical properties, such as light absorption, of a colloidal nano-material, provides information on the biphasic, solid - liquid system microstructure. The nano-material under study is a magnetic liquid (ferrofluid). The disperser agent is petroleum mineral oil and the dispersed material is a brown spar powder (nano-particles). The stabilizer is oleic acid. Light absorption through ferrofluid samples reveals the tendency of solid particles in a colloidal solution to form aggregates. The paper emphasizes the linear dependence between the spectral absorption coefficient, concentration and wavelength. The aggregates cause deviations of the extinction coefficient from values according to the Bouger-Lambert-Beer law. Fe3O4 aggregates sized 58.76 nm are formed in the system. The average number of nano-particles forming aggregates is 6. The magnetic liquid to be studied is secure stable and, thus, trustful in technological and biological applications.
History and challenges of barium titanate: Part II
Authors: Vijatovic M.M. , Bobic J.D. , Stojanovic B.D.
Published: February 2009

Barium titanate is the first ferroelectric ceramics and a good candidate for a variety of applications due to its excellent dielectric, ferroelectric and piezoelectric properties. Barium titanate is a member of a large family of compounds with the general formula ABO3 which is called perovskite. Barium titanate can be prepared using different methods. The synthesis method depends on the desired characteristics for the end application and the method used has a significant influence on the structure and properties of barium titanate materials. In this review paper, in Part II the properties of obtained materials and their application are presented.
Electromagnetic wave scattering on imperfect cloaking devices
Authors: Isic G. , Beltaos A. , Gajic R. , Hingerl K.
Published: February 2009

Cloaking devices based on the coordinate transform approach enable, in principle, a perfect concealment of a region in space provided that the material composing the cloaking shell meets certain criteria. To achieve ideal cloaking it is necessary that the shell material parameters have singular values on the surface bounding the cloaked region which is unphysical. In this paper we assume finite values of cloak parameters and apply the scattering theory formalism to give an estimate of the overall performance of an 'imperfect' cloak. We perform full-wave numerical calculations and use our theoretical results to discuss them.
Kinetics of the α-β phase transformation in seeded Si3N4 ceramics
Authors: Bucevac D. , Boskovic S. , Matovic B.
Published: February 2009

The ?-? phase transformation in Si3N4 was studied for seeded samples using an Y2O3-Al2O3 mixture as a sintering aid. The concentration of ?-seeds varied from 0 to 5 wt.%. The results showed that ?-? phase transformation followed the first-order reaction. The calculated activation energy for seeded samples was in the range from 348 to 378 KJ/mol, indicating boundary reaction as the rate limiting step.
Laser irradiation of SiC-MoSi2 composite ceramics
Authors: Aguilar Marquez , Vlasova M. , Reséndiz-González M.C. , Kakazey M. , Cruz Mayorga , Bykov A. , Tomila T. , Stetsenko V.
Published: February 2009

The influence of continuous IR laser irradiation (? = 1064 nm, P = 240 mW) on SiC-MoSi2 composite ceramics was investigated by X-ray diffraction, electron microscopy, atomic force microscopy, and X-ray microanalysis. The irradiation of specimens was carried out in air. It was established that, due to heating of the surface under laser irradiation, oxidation of SiC and MoSi2 and sublimation of SiO (SiO2) and MoO3 take place. Depending on the content of the components in the ceramics and the irradiation time, SiO2 or MoO3 layers form on the surface or disappear from it. For a long irradiation time, the oxidation and cleaning of the surface (sublimation of oxides) are cyclic in character.
Effect of al content on reaction laser sintering of Ni-Al powder
Authors: Qin L. , Hu J. , Cui C. , Wang H. , Guo Z.
Published: February 2009

Laser reactive sintering, i.e., laser-induced self-propagating reaction sintering synthesis was used for the preparation of nickel aluminide intermetallic compounds. The experimental parameters controlling the ignition step such as ignition time and adiabatic temperature were calculated as a function of initial stoichiometry. Al mole ratio in initial powder mixture was varied from 25% to 50% for controlling adiabatic temperature. The increase in Al powder content resulted in the rise in adiabatic temperature and the morphology change of nickel aluminide compounds from needle-like to blocky.
Fabrication and microstructures of YAG transparent ceramics
Authors: Liu M. , Wang S.W. , Tang D.Y. , Chen L.D. , Ma J.
Published: February 2009

YAG transparent ceramics with different microstructures were fabricated via solid-state reaction of high-purity powders. Influences of grain size, grain-boundary phases on the transmittance of the fabricated YAG ceramics were experimentally investigated. Our results confirm that the optical scattering loss in YAG ceramics is mainly caused by pores. Grain size did not influence the transmittance, and the grain-boundary phases with similar refractive index to the host only affected slightly the transmittance of the YAG transparent ceramics.
Effect of cold swaging and heat treatment on properties of the P/M 91W-6Ni-3Co heavy alloy
Authors: Katavic B. , Nikacevic M. , Odanovic Z.
Published: February 2009

This paper describes the effects of rotary swaging and heat treatment under different conditions on mechanical properties and microstructure of the P/M 91W-6Ni-3Co alloy. The investigation was performed on cold rotary swaging rods with 10, 20 and 25% reduction in area, heat treated at 11300C for 90min under different cooling conditions and strain-aged at temperatures from 300 to 8000C for 60, 180 and 360min. Tensile and toughness testing of rotary swaging rods showed that increase in the reduction resulted in intensive strengthening and toughness lowering. The results of tensile and toughness testing of heat treated rods have shown a decrease in strength, ductility and partly toughness in comparison with the mechanical properties of swaged alloys. The results of strain aged rods demonstrate that, for this cold rotary swaging alloy, there is a temperature range from 500 to 6000C for 60min in which the maximum ultimate strength and hardness may be attained.
Crystallization kinetics of K2O·TiO2·3GeO2 glass studied by DTA
Authors: Grujic S. , Blagojevic N. , Tosic M. , Zivanovic V. , Nikolic J.
Published: February 2009

Crystallization kinetics of K2O?TiO2?3GeO2 glass was investigated by differential thermal analysis (DTA). Experiments were performed on powder samples with a particle size < 0.037 mm. The glass samples were heated at different rates in the temperature range 20-750?C. The kinetic parameters, activation energy for the crystallization process, Ec and Avrami exponent, n were calculated. Powder X-ray diffraction analysis (XRD) of crystallized glass reveals the presence of crystalline K2O?TiO2?3GeO2 indicating polymorphic crystallization with interface controlled crystal growth.
The role of pedagogical historiography in forming pedagogical knowledge
Authors: Vujisic-Zivkovic Natasa
Published: February 2009

This paper discuses the role of pedagogical historiography in forming pedagogical knowledge, both from the aspect of history and from the aspect of the present status of this discipline. Our aim is to observe the problems of pedagogical historiography, as a scientific and teaching discipline, in the context of forming of pedagogical knowledge. The process of transformation of heuristic function of the history of pedagogy is analyzed - from the traditional approach which emphasizes its role in forming pedagogical culture to the orientation of historical research and education in pedagogy towards theoretical and professional knowledge. The development of history of pedagogy as a scientific discipline is mostly observed through three phases: the first, focused on research of the development of pedagogical ideas and/or school system, lasted until the 1960s, when it was replaced by social history of education, while today it is mostly spoken about the 'cultural history of education'. The evolution of pedagogical historiography is also followed by the changes in its relation towards theory and practice of education, which is especially dealt with in this paper. In the conditions of radical changes in epistemology of social sciences and university reform, pedagogical historiography faces the question of its own relevance.
Psychology of development of moral reasoning: Problem-oriented overview of the field
Authors: Miric Jovan
Published: February 2009

First and foremost, this paper provides a short historical reminder of the emergence of the field of psychology of development of moral reasoning. In the second part of the paper, the author offers a problem-oriented overview of the field, that is, one possible classification of particular groups of problems for empirical research. This overview does not only point out to the problems that were more and that were less studied (e.g.. evaluative moral judgment and reasoning, distinguishing between moral and extra-moral rules and norms) and to those that were relatively neglected (i.e. understanding moral situations), but also to the problems that psychologists did not even recognize as research problems. Such are the problems of development of moral concepts, meaning of moral words etc. Finally, the author also points out to the fact that this classification could be taken as one way to define the field, that is, the way to determine the boundaries of its subject of studying.
Subject domain differences in secondary school teachers' attitudes towards grouping pupils by ability
Authors: Hallam Susan , Ireson Judith
Published: February 2009

Previous research has revealed that teachers' attitudes to ability grouping are influenced by the type of ability grouping adopted in the school where they teach. This research aimed to compare the attitudes of teachers of different subjects teaching low, high or mixed ability classes in years 7 to 9 in 45 secondary schools. Over 1500 teachers from 45 secondary schools, with a range of subject specialisms completed a questionnaire which elicited their responses to statements of beliefs about ability grouping and its effects. Teachers of mathematics and modern foreign languages were more in favour of structured ability grouping than those teaching English and humanities. Science, arts and PE, and ICT, design and business studies teachers expressed intermediate attitudes. Attitudes were determined in part by conceptions of the nature of the subject but also by the type of ability groupings adopted by the school in which they taught. In taking decisions about the type of ability grouping to adopt consideration needs to be given to the nature of the subject matter to be taught and the attitudes of the teachers who teach that subject.
The challenges of leader's role of the teacher
Authors: Pavlovic Branka
Published: February 2009

This paper deals with the leader's role of the teacher in school, as one of central persons in educational process, and the creation of a climate stimulative for learning. Besides defining the leader's role of the teacher, which is here treated as an aspect of participation in decision-making and responsibility, different manifestations of that role in school are discussed, as well as its importance for contemporary education and possibilities and challenges of encouraging the development of teachers-leaders. The results of several studies that present the leader's role of the teacher from the point of view of different participants in school life are displayed. It is concluded that leadership of teachers in school is desirable and that it should be encouraged, since it contributes to democratisation of school climate, stimulates pupils' achievements, motivates other teachers, as well as that it is necessary to analyze numerous obstacles to leadership of teachers. Among the most important obstacles are those stemming from institutional inertia, the fear of taking risks and resistance of school principals to developing the leadership of teachers.
'Hidden poverty' of teachers: Status, consequences and overcoming strategies
Authors: Bogunovic Blanka , Stankovic Ivana
Published: February 2009

The consequences of reduced financial and other possibilities in the period of social transition are reflected on the quality of life and work of teachers, and thereby indirectly on education of pupils as well. Aims: (1) to determine teachers' estimation of their own financial status and subjective perception of teachers' poverty; (2) to examine in which way the personal perception of poverty of teachers is linked with the quality of their engagement in curricular and extracurricular activities; (3) to examine which economic and psychological strategies teachers use in overcoming stress because of the lower financial status; (4) to examine whether there are differences between teachers with regard to socio-demographic variables and the previously established goals. Sample consists of 141 teachers of music and general education schools in Belgrade and the interior of the country. Method: research is explorative and uses qualitative and psychometric methods of analysis. Results point out to the structure of 'hidden poverty' of teachers: average and poor financial status, financial and logistic support of the extended family, additional job, unfulfilled financial expectations regarding the educational status and ungratified higher needs. Teachers estimate that real poverty of educational system and 'hidden poverty' of teachers are reflected on the quality of certain aspects of educational process as a whole and in certain elements: teacher's personal life and work motivation, authority in school, quality of teacher's engagement in tuition and the possibility of professional specialization. Teachers use financial and psychological strategies for overcoming stress that can be determined as: moralist compensatory, evasive, inappropriate, emotional, relying on family and friendly supportive systems and activist. Conclusion: primarily subjective and spiritual impoverishment of the stratum of highly educated people, who are, in addition to this, the bearers of upbringing and education of new generations, weakens the strength of the educated middle social stratum which should be a generator of changes and bearer of development of social values.
Gas chromatography–mass spectrometry assay for determination of Nτ-methylhistamine concentration in canine urine specimens and fecal extracts
Authors: Ruaux Craig G. , Wright Jeannie M. , Steiner Jörg M. , Williams David A.
Published: February 2009

Objective—To develop and validate a gas chromatography–mass spectrometry (GC-MS) method for determination of Nτ-methylhistamine (NMH) concentration in canine urine and fecal extracts and to assess urinary NMH concentrations in dogs with mast cell neoplasia and fecal NMH concentrations in dogs with protein-losing enteropathy.

Sample Population—Urine specimens were collected from 6 healthy dogs and 7 dogs with mast cell neoplasia. Fecal extracts were obtained from fecal specimens of 28 dogs with various severities of protein-losing enteropathy, as indicated by fecal concentration of α1-proteinase inhibitor.

Procedures—NMH was extracted directly from urine, and fecal specimens were first extracted into 5 volumes of PBSS containing 1% newborn calf serum. Nτ-methylhistamine in specimens was quantified via stable isotope dilution GC-MS. The assay was validated via determination of percentage recovery of known amounts of NMH and interassay coefficients of variation. Urinary excretion of NMH was evaluated by means of NMH-to-creatinine concentration ratios.

Results—Recovery of NMH in urine and fecal extracts averaged 104.6% and 104.5%, respectively. Interassay coefficients of variation ranged from 5.4% to 11.7% in urine and 12.6% to 18.1% in fecal extracts. Urinary NMH excretion was significantly increased in dogs with mast cell neoplasia, compared with that in healthy dogs. No correlation was detected between severity of protein-losing enteropathy and fecal NMH concentration.

Conclusions and Clinical Relevance—This method provided a sensitive, reproducible means of measuring NMH in canine urine and fecal extracts. High urinary NMH-to-creatinine concentration ratios in dogs with mast cell neoplasia are consistent with increased histamine release in this disease.
Evaluation of polysulfated glycosaminoglycan or sodium hyaluronan administered intra-articularly for treatment of horses with experimentally induced osteoarthritis
Authors: Frisbie David D. , Kawcak Chris E. , McIlwraith C. Wayne , Werpy Natasha M.
Published: February 2009

Objective—To assess clinical, biochemical, and histologic effects of polysulfated glycosaminoglycan (PSGAG) or sodium hyaluronan administered intra-articularly in treatment of horses with experimentally induced osteoarthritis.

Animals—24 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Eight horses received hyaluronan (20 mg) and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Eight horses received PSGAG (250 mg) and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Eight control horses received 2 mL of saline (0.9% NaCl) solution and amikacin (125 mg) intra-articularly on study days 14, 21, and 28. Clinical, radiographic, synovial fluid analysis, gross, histologic, histochemical, and biochemical findings were evaluated.

Results—No adverse treatment-related events were detected. Induced osteoarthritis caused a substantial change in lameness, response to flexion, joint effusion, and radiographic findings, and of these, synovial fluid effusion was reduced with PSGAG, compared with control horses. No changes in clinical signs were seen with PSGAG or hyaluronan, compared with control horses. Histologically, the degree of synovial membrane vascularity and subintimal fibrosis was significantly reduced with PSGAG treatment, compared with controls. Histologically, significantly less fibrillation was seen with hyaluronan treatment, compared with controls.

Conclusions and Clinical Relevance—Results indicated that PSGAG and hyaluronan had beneficial disease-modifying effects and are viable therapeutic options for osteoarthritis in horses.
Evaluation of topically administered diclofenac liposomal cream for treatment of horses with experimentally induced osteoarthritis
Authors: Frisbie David D. , McIlwraith C. Wayne , Kawcak Chris E. , Werpy Natasha M. , Pearce Gregory L.
Published: February 2009

Objective—To assess the clinical, biochemical, and histologic effects of topically administered diclofenac liposomal cream (DLC) in the treatment of horses with experimentally induced osteoarthritis.

Animals—24 horses.

Procedures—Osteoarthritis was induced arthroscopically in 1 middle carpal joint of all horses. Eight horses treated with DLC were given 7.3 g twice daily via topical application. Eight horses treated with phenylbutazone were given 2 g orally once daily. Eight control horses received no treatment. Evaluations included clinical, radiographic, magnetic reso-nance imaging, synovial fluid, gross, and histologic examinations as well as histochemical and biochemical analyses.

Results—No adverse treatment-related events were detected. Horses that were treated with DLC or phenylbutazone had significant clinical improvement of lameness, unlike the control horses. Treatment with DLC induced significant improvement in staining and total articular glycosaminoglycan content, compared with no treatment. Treatment with phen-ylbutazone induced significant reduction in synovial fluid prostaglandin E2 concentration, compared with DLC and no treatment. Treatment with DLC induced significantly less radial carpal bone sclerosis and overall gross cartilage erosion, compared with phenylbutazone.

Conclusions and Clinical Relevance—Results indicated that DLC had both clinical sign–modifying and disease-modifying effects. Only clinical sign–modifying effects were detected in association with phenylbutazone administration. Treatment with DLC had significant beneficial effects, compared with phenylbutazone, and no detrimental effects. Results suggested that DLC is a viable therapeutic option for horses with osteoarthritis.
Precision, reproducibility, and clinical usefulness of measuring the Norberg angle by means of computerized image analysis
Authors: Comhaire Frank H. , Criel Ann C. C. , Dassy Christian A. A. , Guévar Pierre G. J. , Snaps Frédéric R.
Published: February 2009

Objective—To evaluate the precision, reproducibility, and clinical usefulness of measuring the Norberg angle (NA) by means of a computerized system of image analysis.

Sample Population—1,182 consecutive radiographs of hip joints of various breeds of dogs assessed for hip dysplasia and 72 radiographs of hip joints of German Shepherd Dogs.

Procedures—Radiographs were assessed by a panel of 4 experts in consensus, and NAs were measured by means of a computerized system. Results of classification of hip dysplasia according to the Fédération Cynologique Internationale (FCI) and NAs were compared within dogs and among breeds.

Results—Measurement of the NA by means of image analysis was twice as reproducible as that via calipers. Mean NA of left hip joints was 0.38° higher than that of right hip joints. The NA values accurately discriminated between hip joints of dogs without or with hip dysplasia, provided the values were also expressed as percentile rank based on the cumulative frequency distribution of NAs within the breed, and had good power to discriminate among various FCI classifications of hip joints. Mean NA for each dog breed as calculated by use of the lower of 2 NAs for each dog was highly variable and was moderately correlated with the existence of hip dysplasia (r = 0.5).

Conclusions and Clinical Relevance—Computer-assisted measurement of the NA was useful in assessing hip joint quality and can be implemented for quality control and standardization of the FCI classification and for international comparisons.
Effects of flunixin meglumine on recovery of colonic mucosa from ischemia in horses
Authors: Matyjaszek Sarah A. , Morton Alison J. , Freeman David E. , Grosche Astrid , Polyak Maximilian M. R. , Kuck Hilken
Published: February 2009

Objective—To examine the effects of flunixin meglumine (FM) on recovery of colonic mucosa from experimentally induced ischemia in horses.

Animals—14 research horses.

Procedures—Ischemia was induced in the colons of anesthetized horses for 2 hours. Afterward, horses received saline (0.9% NaCl) solution (12 mL, IV, q 12 h; n = 7) or FM (1.1 mg/kg, IV, q 12 h; 7) and were allowed to recover for 18 hours after termination of the ischemic event. Postoperative pain scores were recorded every 4 hours throughout the recovery period. At the end of the recovery period, horses were anesthetized, and ischemic and nonischemic segments of colonic mucosa were harvested for histologic evaluation, western blot analysis, and in vitro assessment of transepithelial electric resistance (TER) and transmucosal flux of tritium-labeled (3H-) mannitol. Horses were then euthanatized.

Results—Flunixin meglumine significantly lowered pain scores at the first postoperative recording. There were no significant differences between treatment with saline solution and FM in any of the measurements for TER, 3H-mannitol flux, histomorphometric variables, neutrophil infiltration (detected via calprotectin immunostaining), and expressions of cyclooxygenase-1 and -2. After both treatments, TER declined significantly in nonischemic tissues in vitro, whereas it increased significantly in ischemic-injured tissues.

Conclusions and Clinical Relevance—Flunixin meglumine did not affect recovery of equine colonic mucosa from ischemic injury, and continued use in horses with colonic ischemia is therefore justified.