bluuebunny/crossref_metadata_2025 huggingface dataset:
At the Watershed: Preparing for Research Data Management and Stewardship at the University of Minnesota Libraries
Authors: Delserone Leslie M.
Published: March 2009

Like many research universities, the University of Minnesota (UMN), and its Libraries, attempts to understand the nature and intensity of data produced by its researchers, and address the management and stewardship of its institutional research output. The recent activities of the Libraries, in support of and in conjunction with campus-wide efforts, illustrate a set of approaches that show the Libraries to be at the watershed, integrated into and contributing leadership to the growing river of campus-wide exploration and planning of cyberinfrastructure needs. This brief article highlights the hiring of the “science librarian cohort,” the Libraries’ study concerning the needs and behaviors of scientific researchers, the implementation of the University Digital Conservancy, the Libraries’ involvement in the UMN’s Research Cyberinfrastructure Alliance, and its initiation of the e-Science and Data Services Collaborative.
Institutional Repositories in the UK: The JISC Approach
Authors: Jacobs Neil , Thomas Amber , McGregor Andrew
Published: March 2009

As the uptake of repositories increases, JISC continues to support UK universities in developing their services. This article describes some of the key areas of activity at the institutional and national levels, illustrates the way in which effective networked repositories can support academics, and showcases the contribution of JISC-funded projects to the global growth of repository services.
Leveraging Short-term Opportunities to Address Long-term Obligations: A Perspective on Institutional Repositories and Digital Preservation Programs
Authors: McGovern Nancy Y. , McKay Aprille C.
Published: March 2009

Until now, information retrieval (IR) managers have been absorbed by efforts to increase the amount and quality of scholarly deposits. Other pressing concerns have been to develop the software, standards, and other tools to insure access, exchange, and discovery of the works in the IRs. But building an IR without making plans for technological, organizational, and resourcing sustainability is like building a house on sand.

At this particular juncture, there are opportunities to enhance the efforts of both institutional repository implementation and digital preservation program development by bringing together the strengths of each. This paper first explores the developmental paths and intersections of digital preservation and institutional repositories, considers the current status of both, and looks ahead toward the opportunities and challenges inherent in their convergent future.
The Progenitor Cell Compartment in the Feline Liver: An (Immuno)Histochemical Investigation
Authors: Ijzer J. , Kisjes J. R. , Penning L. C. , Rothuizen J. , Van Den Inch T. S. G. A. M
Published: March 2009

The hepatic progenitor compartment is of vital importance in liver regeneration when hepatocellular replication is impaired, as it occurs in acute fulminant hepatitis or severe liver fibrosis. It consists of resident progenitor cells in the normal liver, and ductular reaction and intermediate hepatobiliary cells in diseased livers. An histologic and immunohistochemical study was conducted to demonstrate putative hepatic progenitor cells in the normal liver (n = 5) and in a range of hepatic diseases (n = 13) in the cat. Formalin-fixed, paraffin-embedded specimens were stained with HE, the van Gieson stain, and the reticulin stain according to Gordon and Sweet, and immunohistochemically stained for cytokeratin-7 (CK7), human hepatocyte marker 1 (Heparl), and multidrug resistance-binding protein-2/ATP binding cassette C2 (MRP2). The normal feline liver contains a liver progenitor cell morphologically similar to humans and dogs, which resides in the canal of Hering. In acute and chronic feline liver diseases a ductular reaction is present, whether in the parenchyma or in a portal or septal location. The putative progenitor cells could easily be demonstrated by staining for CK7, whereas they were generally negative for Heparl and MRP2. In a parenchymal ductular reaction mitotic figures and cells with an intermediate hepatobiliary phenotype could be demonstrated. This is the first account of hepatic progenitor cells in feline liver.
Sleep Environment Risk Factors for Sudden Infant Death Syndrome: The German Sudden Infant Death Syndrome Study
Authors: Vennemann Mechtild M. , Bajanowski Thomas , Brinkmann Bernd , Jorch Gerhard , Sauerland Cristina , Mitchell Edwin A. ,   the GeSID Study Group
Published: March 2009

OBJECTIVE. Our goal was to investigate the risk factors for sudden infant death syndrome in the infants' sleep environment for a population in which few infants sleep prone as a result of education campaigns.

METHODS. This was a population-based sudden infant death syndrome case-control study over 3 years (1998–2001) in Germany.

RESULTS. There were 333 sudden infant death syndrome cases and 998 matched controls. Although only 4.1% of the infants were placed prone to sleep, those infants were at a high risk of sudden infant death syndrome. Those who were unaccustomed to sleeping prone were at very high risk, as were those who turned to prone. Bed sharing (especially for infants younger than 13 weeks); duvets; sleeping prone on a sheepskin; sleeping in the house of a friend or a relative (compared with sleeping in the parental home); and sleeping in the living room (compared with sleeping in the parental bedroom) increased the risk for sudden infant death syndrome; pacifier use during the last sleep was associated with a significantly reduced risk of sudden infant death syndrome.

CONCLUSIONS. This study has clarified the risk factors for sudden infant death syndrome in a population where few infants sleep prone. This study supports the current recommendations of the American Academy of Pediatrics. This study has identified several novel risk factors for sudden infant death syndrome: an increased risk if the infants sleeps outside the parental home, death in the living room, and the high risk when sleeping prone on a sheepskin; however, because the numbers of cases in these groups are small, additional studies are needed to confirm these findings.
Lysosomal Storage Disorders in the Newborn
Authors: Staretz-Chacham Orna , Lang Tess C. , LaMarca Mary E. , Krasnewich Donna , Sidransky Ellen
Published: March 2009

Lysosomal storage disorders are rare inborn errors of metabolism, with a combined incidence of 1 in 1500 to 7000 live births. These relatively rare disorders are seldom considered when evaluating a sick newborn. A significant number of the >50 different lysosomal storage disorders, however, do manifest in the neonatal period and should be part of the differential diagnosis of several perinatal phenotypes. We review the earliest clinical features, diagnostic tests, and treatment options for lysosomal storage disorders that can present in the newborn. Although many of the lysosomal storage disorders are characterized by a range in phenotypes, the focus of this review is on the specific symptoms and clinical findings that present in the perinatal period, including neurologic, respiratory, endocrine, and cardiovascular manifestations, dysmorphic features, hepatosplenomegaly, skin or ocular involvement, and hydrops fetalis/congenital ascites. A greater awareness of these features may help to reduce misdiagnosis and promote the early detection of lysosomal storage disorders. Implementing therapy at the earliest stage possible is crucial for several of the lysosomal storage disorders; hence, an early appreciation of these disorders by physicians who treat newborns is essential.
Resuscitation of Likely Nonviable Newborns: Would Neonatology Practices in California Change if the Born-Alive Infants Protection Act Were Enforced?
Authors: Partridge J. Colin , Sendowski Mya D. , Drey Eleanor A. , Martinez Alma M.
Published: March 2009

BACKGROUND. The effects of the Born-Alive Infants Protection Act of 2002, which defines the legal status of live-born infants have not been evaluated.

OBJECTIVE. To study neonatologists' perceptions and the potential effects of the Born-Alive Infants Protection Act and subsequent Department of Health and Human Services enforcement guidelines on resuscitation and comfort care for infants born at 20 to 24 weeks' gestation.

METHODS. From August 2005 to November 2005, we mailed surveys to all 354 neonatologists practicing in California. Surveys asked physicians to characterize their knowledge of and attitudes toward this legislation and enforcement guidelines, current resuscitation and comfort-care practices for extreme prematurity, anticipated changes in practice were the enforced, and demographic information. We hypothesized that enforcement would alter thresholds for resuscitation and care.

RESULTS. We obtained 156 completed surveys (response rate: 44%); 140 fulfilled criteria for analysis. More than half of the neonatologists had not heard of this Act or the enforcement guidelines. Screening examinations at birth were infrequent (<20%) at gestational ages of <23 weeks. Although 63% of neonatologists felt that the Act clarified the definition of born-alive infants, nearly all (>90%) criticized the legislation; only 6% felt that it should be enforced. If it were enforced, physicians predicted that they would lower birth weight and gestational age thresholds for resuscitation and comfort care.

CONCLUSIONS. The Born-Alive Infants Protection Act clarified the legal status of “born-alive” infants, but enforcement guidelines fail to clarify what measures are appropriate when survival is unlikely. The Act may constrain resuscitation options offered to parents, because neonatologists anticipate medicolegal threats if they pursue nonintervention. If this legislation were enforced, respondents predicted more aggressive resuscitation potentially increasing risks of disability or delayed death. Until outcomes for infants of <24 weeks' gestation improve, legislation that changes resuscitation practices for extreme prematurity seems an unjustifiable restriction of physician practice and parental rights.
Endostatin Concentration in Cord Plasma Predicts the Development of Bronchopulmonary Dysplasia in Very Low Birth Weight Infants
Authors: Janér Joakim , Andersson Sture , Kajantie Eero , Lassus Patrik
Published: March 2009

INTRODUCTION. Endostatin is an antiangiogenic growth factor. Together with proangiogenic growth factors it acts to shape the developing vasculature. Dysregulation of angiogenesis is a component in the pathogenesis of bronchopulmonary dysplasia.

OBJECTIVE. Our goal was to study whether the concentration of circulating endostatin at birth is associated with the development of bronchopulmonary dysplasia in very low birth weight infants.

PATIENTS AND METHODS. Endostatin concentration was measured in cord plasma from 92 very low birth weight infants (gestational age < 32 weeks; birth weight < 1500 g) and 48 healthy term infants (gestational age > 37 weeks; birth weight > 2500 g).

RESULTS. Endostatin concentration in very low birth weight infants was lower than in healthy term infants. Within the very low birth weight group no correlation existed between endostatin concentration and gestational age or relative birth weight. Very low birth weight infants who subsequently developed bronchopulmonary dysplasia had higher cord endostatin than those who did not. Higher endostatin concentration was associated with higher odds for bronchopulmonary dysplasia. Adjusted for gestational age, the odds for bronchopulmonary dysplasia were higher.

CONCLUSIONS. Circulating endostatin in term infants was higher than in very low birth weight infants, suggesting a temporal pattern for fetal endostatin concentration. In very low birth weight infants a high concentration of circulating endostatin at birth is associated with the subsequent development of bronchopulmonary dysplasia.
Early Exposure to Movie Smoking Predicts Established Smoking by Older Teens and Young Adults
Authors: Dalton Madeline A. , Beach Michael L. , Adachi-Mejia Anna M. , Longacre Meghan R. , Matzkin Aurora L. , Sargent James D. , Heatherton Todd F. , Titus-Ernstoff Linda
Published: March 2009

OBJECTIVE. Movie smoking exposure is a strong predictor of smoking initiation by adolescents; however, we do not know whether it is a long-term predictor of established smoking. We conducted a prospective study to determine whether movie smoking exposure during early adolescence predicts established smoking in older teens and young adults.

DESIGN. We assessed movie smoking exposure and smoking status through a written school-based survey in 1999, when participants were 10 to 14 years of age. We enrolled 73% (n = 2603) of those who had never tried smoking in a follow-up study. In 2006–2007, we conducted telephone interviews with 69% (n = 1791) of the cohort to ascertain current smoking status. The primary outcome was established smoking, defined as having smoked >100 cigarettes. Mean age at follow-up was 18.7 years.

RESULTS. Thirteen percent (n = 235) progressed from never smoking to established smoking during the follow-up period. Eighty-nine percent (n = 209) of established smokers smoked during the 30 days before the survey. Even after controlling for a wide range of baseline characteristics, the relative risk for established smoking increased by one third with each successive quartile of movie smoking exposure. Those in the highest quartile for baseline movie smoking exposure were twice as likely to be established smokers at follow-up compared with those in the lowest quartile.

CONCLUSIONS. Movie smoking exposure significantly predicted progression to established smoking in long-term follow-up. We estimate that 34.9% of established smoking in this cohort can be attributed to movie smoking exposure.
Further evidence on the causal relationship between government spending and economic growth: The case of Greece, 1958–2004
Authors: Katrakilidis C. , Tsaliki P.
Published: March 2009

The purpose of this paper is the empirical testing of the relationship between economic growth and government spending and, at the same time, to determine the extent to which economic growth causes growth in government expenditures (Wagner’s law) or the other way around (Keynesian hypothesis). The econometric analysis, using data for the Greek economy covering the period 1958–2004 and based on recent developments in the theory of cointegrated processes, reveals a long-run equilibrium relationship between government expenditures and economic output. Furthermore, the analysis detects causal effects in both the short-run and long-run horizon running from government expenditures to the level of economic activity and vice versa.
All chemical YBa2Cu3O7 superconducting multilayers: Critical role of CeO2 cap layer flatness
Authors: Coll M. , Gàzquez J. , Huhne R. , Holzapfel B. , Morilla Y. , García-López J. , Pomar A. , Sandiumenge F. , Puig T. , Obradors X.
Published: March 2009

New advances toward microstructural improvement of epitaxial CeO2 films grown by chemical solution deposition and their use as buffer layers for YBa2Cu3O7 (YBCO) films are presented. We demonstrate that the degree of epitaxy and the fraction of (001) atomically flat surface area are controlled by the incorporation of tetravalent (Zr4+) or trivalent (Gd3+) cations into the ceria lattice. The degree of epitaxy has been investigated by means of Rutherford backscattering spectroscopy-channeling and reflection high-energy electron diffraction, and a new methodology is also presented to quantify the fraction of (001) atomically flat area from atomic force microscopy images. Results are further correlated with the superconducting properties, microstructure, and texture of YBCO films grown by the trifluoroacetate route. A comparison with pulsed laser deposition and YBCO films grown on the same ceria layers is also presented. This growth procedure has allowed us to obtain all chemical multilayer films with controlled microstructure and critical current densities above 4 MA cm−2 at 77 K.
Rate-change instrumented indentation for measuring strain rate sensitivity
Authors: Pan D. , Chen M.W.
Published: March 2009

A rate-change instrumented indentation method is introduced to experimentally characterize the strain rate sensitivity of high strength materials, such as metallic glasses and nanocrystalline metals, which generally possess low rate sensitivity at room temperature. This technique has been validated herein, via self-consistency between rate jump and rate drop measurements, as a viable way to characterize rate dependent deformation behavior and thereby the underlying micromechanisms of plastic flow.
Chill-zone aluminum alloys with GPa strength and good plasticity
Authors: Li Yan , Georgarakis Konstantinos , Pang Shujie , Charlot Frédéric , LeMoulec Alain , Brice-Profeta Sandrine , Zhang Tao , Yavari Alain Reza
Published: March 2009

Using a cold graphite mold casting method, bulk AlNiY chill-zone alloys were prepared at hypereutectic compositions with Al content from 85 at.% to 94 at.%. It was found that ultra-hard surface layers with a thickness of about 200 μm and submicron grain size form when the melt can be undercooled without heterogeneous nucleation at the mold contact surface. This hard chill-zone forming in contact with the mold possesses Vickers microhardness Hv about 350–420 and is thus harder than fully amorphous Al alloys. In compression, ultimate strength more than 1.1 GPa and true strain more than 150% without failure were achieved simultaneously. The combination of high strength and good plasticity will be discussed in relation to the special structure of the chill-zone alloy.
Voluntary Ingestion of Soft Plastic Fishing Lures Affects Brook Trout Growth in the Laboratory
Authors: Danner G. Russell , Chacko Jim , Brautigam Francis
Published: March 2009

Thirty-eight brook trout Salvelinus fontinalis were fed a commercial trout diet mixed with a free-choice assortment of soft plastic lures (SPLs) over a 90-d period. Fish growth was recorded and compared with that of a control group. The brook trout readily ate the SPLs from the water's surface as well as from the tank bottom. At the conclusion of the study, SPLs were recovered from the stomachs of 63% of the test fish. Several fish stomachs contained multiple lures. Twelve percent of the fish voluntarily ingested more than 10% of their body mass in SPLs. These fish lost a significant amount of weight during the study, had a significant decrease in body condition factor, and began displaying anorexic behaviors. For these reasons, anglers should be discouraged from discarding used SPLs in trout waters.
Phosphorus Sorption and Potential Phosphorus Storage in Sediments of Lake Istokpoga and the Upper Chain of Lakes, Florida, USA
Authors: Belmont Marco A. , White John R. , Reddy K. Ramesh
Published: March 2009

Phosphorus (P) can be an important nutrient in regulating primary productivity in lakes. The ability of lake sediments to retain P from external sources depends on the physiochemical characteristics of the sediment. To assess the P dynamics in Lake Istokpoga and the upper chain of lakes that drain into Lake Okeechobee, Florida, USA, sorption properties of batch sediment samples for Lakes Tohopekaliga, Cypress, Hatchineha, Kissimmee, and Istokpoga were characterized under aerobic and anaerobic conditions. Langmuir model parameters fit the experimental data well (in general, r2 > 0.70). There were strong correlations between P sorption and total C, total P, Ca, Mg, Fe, and Al (r = 0.83–0.97). Equilibrium P concentration values ranged between 0.001 and 0.192 mg L−1 for aerobic conditions. A single‐point isotherm (initial concentration, 5 mg L−1) was found for a wide range of sediment types, which allows estimation of the maximum potential sorption (Smax) as 1.7 times the sorption (Smax = 1.7 S5). Results suggest that although these sediments have high P sorption capacities, the lake sediments may release P into the water column by desorption under aerobic conditions if water‐column P concentrations are low enough (<0.036 mg L−1 for Lake Tohopekaliga and <0.003–0.027 mg L−1 for the other four lakes). Current watershed management strategies must balance efforts to reduce P inputs into the lakes from point and nonpoint sources against lowering the water‐column P concentration to such a low level that the lake sediments become a source of P to downstream Lake Okeechobee.
Hydrodistillation kinetics and essential oil composition from fermented parsley seeds
Authors: Stankovic Mihajlo , Nikolic Nada , Stanojevic Ljiljana , Petrovic Slobodan , Cakic Milorad
Published: March 2009

The effect of fermentation conditions on the yield and composition of the essential oil from Petroselinum crispum (Mill.) Nym. ex. A.W. Hill seeds was studied. The yield of essential oil was determined by a Clevenger-type apparatur, and the composition of the oil by GC analysis. The highest yield of essential oil (5.90 mL per 100 g, i.e. 96.7% in regard to the oil content in parsley seeds) was obtained from disintegrated parsley seeds fermented for 4 h at 30?C with a hydromodulus of 1:20 w/v, after the sixth hydrodistillation each lasting 240 minutes. The obtained oil contained ?-pinene, ?-pinene, sabinene, myristicin, 2,3,4,5-tetramethoxy-1-allylbenzene, apiole and 1,2 benzene-dicarbonic acid. The density of the oil (d25) was 1.039 g/mL3, the refractive index, (nD20) was 1.5214 and the oil solubility was 8 volume parts of 80% vol. ethanol for 1 mL of oil.
Extended Brewer thermodynamic basis of facilitated thermal hypo-hyper-d-intermetallic phase formation
Authors: Jaksic Milan , Murase Kuniaki
Published: March 2009

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Study of the ammonium sulfate aqueous solution electrodialysis
Authors: Siminiceanu Ilie , Cotet Ioan , Harasek Michael , Friedl Anton
Published: March 2009

A mathematical model was derived to describe the concentration evolution with time in a batch - recirculation laboratory - scale electrodialyser. The integrated model contains two constants that have been identified by confronting the computed data with the experimental ones. The relative errors of the model including the average values of the identified constants have been estimated. The validated model was finally used to extrapolate the electrodialysis (ED) process in order to determine the necessary time for a complete removal of ammonium sulfate, equivalent to a final dilute content of less than 1.5 mol/m3 ammonium sulfate.
Bioethanol from corn meal hydrolyzates
Authors: Nikolic Svetlana , Rakin Marica , Vukasinovic Maja , Siler-Marinkovic Slavica , Mojovic Ljiljana
Published: March 2009

The two-step enzymatic hydrolysis of corn meal by commercially available ?-amylase and amyloglycosidase and the subsequent or simultaneous ethanol fermentation of the hydrolyzates by Saccharomyces cerevisiae yeast were studied. The conditions of starch hydrolysis, such as substrate and enzyme concentration and the time required for enzymatic action, were optimized taking into account both the effects of hydrolysis and ethanol fermentation. The corn meal hydrolyzates obtained were good substrates for ethanol fermentation by Saccharomyces cerevisiae. A yield of ethanol of more than 80% of the theoretical one was achieved with a satisfactory product to substrate yield Yp/s (g/g) and good ethanol volumetric productivity P (g/lh). No shortage of fermentable sugars was observed during simultaneous hydrolysis and fermentation. Savings in time and energy could be realized by such a process.
Heat of vaporization from the corresponding states principle
Authors: Grozdanic Dusan
Published: March 2009

The heat of vaporization was estimated from the corresponding states principle. The reported values of the functions ?S(0) and ?S(1), or their analytical expressions, are presented. Tabulated values of ?S(0) and ?S(1) were correlated. Estimation procedures were tested on 80 non-polar substances with 397 experimental data points. The model proposed by Sivaraman, Magee and Kobayashi had the best predictive characteristics.
Design, production and characterization of polymeric microparticles containing vitamins for in vitro cell treatment on lab-on-a-chip
Authors: di Croce , Tosi Azzurra , Bilancetti Luca , Luca Giovanni , Mazzitelli Stefania , Bozzuto Nicolina , Nastruzzi Claudio
Published: March 2009

A new lab-on-a-chip prototype, recently described, thanks to the use of integrated circuit technology, can generate dielectrophoretic fields that immobilize and allow the control of single biological objects, such as cells, liposomes, or microspheres immersed in a liquid overhanging and in contact with the same chip. With the aim to design and produce polymeric microparticles for specific lab-on-a-chip applications, in the present paper the preparation and characterization of microparticles based on cellulose acetate and cellulose acetate plus other cellulosic polymers is described by a solvent evaporation procedure. In particular the following aspects were investigated: (a) the polymer solubilities, (b) the experimental parameters used for the solvent evaporation procedure, (c) the effect of dyes on the microparticle preparation and morphology, (d) the entrapment efficiency of the vitamins (D3 and E) and, finally, (e) the release kinetics of vitamins from cellulosic microparticles.
Cultivation conditions preferable for yeast cells to be immobilized into poly(vinyl alcohol) and used in bottled sparkling wine production
Authors: Efremenko Elena , Stepanov Nikolay , Martinenko Nikolay , Gracheva Irina
Published: March 2009

An effective approach to the improvement of the biochemical status of yeast cells before their immobilization was applied to develop a biocatalyst with a high level of cell metabolic activity and viability that could be used for sparkling wine production. According to the approach, the wine-containing medium (pH 3.0) routinely used for the accumulation of champagne yeast biomass under aerobic conditions was replaced by a semi-synthetic one (pH 5.6), usually applied for aerobic yeast growth. The variation of temperature and pH conditions of cell growth showed a modification of the fatty acid pool of yeasts and its importance for the further immobilization of cells into a poly(vinyl alcohol) cryogel. Measurement of the specific intracellular ATP concentration by the bioluminescent method revealed the growth phase favorable for yeast immobilization. The main characteristics of the sparkling wine obtained after four-week fermentation with application of both the free and immobilized cells were similar but, according to the detected energetic status, the viability level of the immobilized cells was considerably higher compared to the free yeast. The CO2 pressure accumulated in the bottles with immobilized cells (up to 500 kPa) after fermentation also appeared notably higher than in the bottles with free yeast.
Insulin release from alginate microspheres reinforced with dextran sulfate
Authors: Silva Catarina , Ribeiro António , Veiga Francisco , Sousa Adriano
Published: March 2009

In a previous study, insulin was efficiently encapsulated in alginate microspheres using an emulsification/internal gelation process. However these microspheres showed a high insulin release at gastric pH, exposing the protein to the harsh conditions of the stomach. In this study, our attempt was to improve insulin release profile by reinforcing the alginate matrix with dextran sulfate (DS). The size distribution was not altered by the presence of DS and the encapsulation efficiency increased to 100%. DS was also able to prevent insulin release at pH 1.2, protecting the insulin from an acidic environment. This effect was explained by an interaction between the permanent negatively charged groups of DS and insulin at low pH. When reinforced alginate microspheres were transferred to neutral pH, dissolution occurred within a few minutes. Increase of the adjuvant concentration did not improve the insulin release profile.
Optimization of the electrostatic droplet generation process for controlled microbead production: Single nozzle system
Authors: Nedovic Viktor , Manojlovic Verica , Pruesse Ulf , Bugarski Branko , Djonlagic Jasna , Vorlop Klaus
Published: March 2009

The aim of this study was to optimize the electrostatic extrusion process for producing small, spherical and uniform microbeads with different fluid viscosities by varying the operating parameters in very wide ranges. Alginate was used as a model polymer. Since the rheological behavior of the solution is one of the parameters that affects the flow dynamics during extrusion, viscosity measurements of solutions with different alginate content were performed. The results obtained in this study show that an electrostatic droplet generator can be used for the production of spherical microbeads of narrow size distribution from low- and medium- viscous fluids (0.5, 1, and 2% of alginate). The average microbead diameter for low-viscous solutions was less than 100 micrometers. It was possible to obtain beads smaller than 500 micrometers that were very uniform (standard deviations less than 2.5%) and of spherical (the shape distortion was less than 1%) from medium-viscous alginate solution (2%). By reducing the polymer flowrate to less than 1 ml/h, even smaller microbeads were produced with diameters of about 300 micrometers. The particular contribution of this paper is in exceeding limitations regarding the use of high-viscous polymer solutions. Optimization of the operating conditions that included the use of a very small needle (0.15 mm), enlargement of the electrode distance to more than 20 cm and a severe reduction in the polymer flow rate to lower than 5 ml/h (for 3% alginate) or 1 ml/h (for 4% alginate) enabled the production of small, entirely spherical and uniform microbeads with an average microbead diameter lower than 500 and 700 micrometers in the case of 3 and 4% of alginate, respectively.
Microbial competition in bioreactors
Authors: Pavlou Stavros
Published: March 2009

Competition for nutrients and other resources is an interaction common among microbial species growing together in the same environment. Such an environment can be created in the laboratory in a bioreactor in order to study this type of interaction and its effect on the microorganisms. Competition tends to eliminate species from the system. The main question then is whether the competing microbial species can coexist and under what conditions. The number of nutrients for which the microorganisms compete plays an important role, while periodic oscillations and spatial heterogeneity have a favorable effect on coexistence.
Statistical dependence of protein secondary structure on amino acid bigrams
Authors: Zivkovic Miodrag , Malkov Sasa , Zaric Snezana , Vujosevic-Janicic Milena , Tomasevic Jelena , Predovic Goran , Blazic Novica , Beljanski Milos
Published: March 2009

The statistical dependence of protein secondary structure on amino acid bigram frequencies was studied. Proteins in the PDBSELECT subset of the Protein Data Bank database were investigated. Protein secondary structures were determined using DSSP software. The conditional probabilities of protein secondary structures were calculated and presented. The results on bigrams show the frequencies of all the possible bigrams in all secondary structure types. These results elucidate some factors important for the prediction of the secondary structures of proteins based on the amino acid sequence.
Modeling of aromatic compound degradation by Pseudomonas putida ATCC 21812
Authors: Montastruc Ludovic , Nikov Iordan
Published: March 2009

Aniline degradation by Pseudomonas putida intact cells in a stirred batch reactor was studied. Since such kinetic data are of significant importance in view of the strain used in large-scale bioreactors, the biodegradation reaction was considered thoroughly. A mathematical model of the process is proposed. The model consists of differential equations describing the time-course of biomass growth and simultaneous aniline utilization, as well as the initial instantaneous substrate adsorption by the cell. The kinetic parameters were determined by using an adapted numerical procedure. In this procedure, the yield coefficient is considered as a variable. The model proposed is adequate to describe the experimental results delivered both from the study and from the literature. The model was compared to several reference models from the literature concerning biodegradation reactions. Bearing in mind that no other model from the literature describes the initial phase of substrate degradation, this specific part of the model proposed is significant for control of the exponential phase of fermentation.
Acid and enyzymatic hyrolysis of Solarium tuberosum L. Glycoalkaloids: Comparison results
Authors: Nikolic Nada , Stankovic Mihajlo , Cakic Milorad
Published: March 2009

A comparison of the results of the acid and enzymatic hydrolysis of GA from potato haulm and tuber sprouts is presented in this paper. Different systems were used for acid hydrolysis: monophase liquid, two-phase liquid-liquid or solid-liquid and three-phase solid-liquid-liquid systems. Enzymatic hydrolysis was carried out by enzymes present in fresh haulm and fresh tuber sprouts and the fresh juice obtained from fresh plant material. The procedure of acid hydrolysis of GA from potato sprouts in a two-phase liquid-liquid system was selected as the optimal procedure for obtaining solanidine. The liquid-liquid system was composed of GA extract with hydrochloric acid as the first liquid phase and chloroform as the second liquid phase. A degree of GA hydrolysis of 96% and a solanidine yield of 1.50 g per 100 g of dried tuber sprouts after 90 minutes were then achieved.
Influence of the precursor on fullerene synthesis in a RF thermal plasma reactor
Authors: Markovic Zoran , Todorovic-Markovic Biljana , Mohai Ilona , Nikolic Zoran , Farkas Zsuzsana , Szepvolgyi Janos , Scheier Paul , Stefan Feil
Published: March 2009

Several graphite powders and mixtures (4827 Asbury Mills, KS4 and KS6 Timcal flake Alfa Aesar, graphite Aldrich, mixture of iron and KS4 powder) having different mean particle size were processed in a RF thermal plasma reactor at atmospheric pressure. It was found that the mean particle size of the precursors has an important, but not exclusive effect on the evaporation efficiency. The micro-structural orderliness of the precursors, which determines their thermal conductivity, is another important property that should be considered in the interpretation of the observed phenomena. In this study a mixture of iron and KS4 graphite proved to be the best precursor of fullerene synthesis. The maximum fullerene yield was 18.4%, which was higher compared to pure graphite powder processing in a RF reactor without the presence of iron.
Singular system theory applied to the evaporator dynamics of a once - through subcritical steam generator: The differential discrete mathematical modeling based approach
Authors: Debeljkovic Dragutin , Jovanovic Mica , Visnjic Nemanja
Published: March 2009

A dynamic thermal-hydraulic mathematical model of the evaporator dynamics of a once - through sub critical steam generator was derived and presented. This model allows the investigation of evaporator dynamics including its transient responses. The evaporator was considered as part of a three-section (economizer, evaporator and super-heater) model with time varying phase boundaries and was described by a set of linearized discrete - difference equations which, with some other algebraic equations, constituted a closed system of equations possible for exact computer solution. This model was derived using the fundamental equations of mass, energy and momentum balance. For the first time, a discrete differential approach was applied in order to investigate such complex, two phase processes. Namely, this approach allows one to escape from the model of this process usually described by a set of partial differential equations and enables one, using this method, to simulate evaporator dynamics in an extraordinarily simple way. In the current literature this approach is sometimes called physical discretization.
Contribution of textile technology to the development of modern compression bandages
Authors: Milosavljevic Svetlana , Skundric Petar
Published: March 2009

Although compression therapy is a key factor in the successful treatment of some circulatory problems in lower limbs, this form of therapy includes some risks if used inappropriately. Based on deliberate application of pressure to a lower limb, using a variety of textile materials, elastic or rigid, in order to produce a desired clinical effects, modern compression therapy presents a good sample of successful penetration of textile technology into the phlebology field of medicine. However, although compression therapy has been in use for over 150 years, there exists a low awareness among practitioners and patients on product usage, application techniques and benefits of appropriate selection of bandages for determined types of leg venous diseases. Also, not all manufacturers of compression textile materials seem to be conscious of end - users' needs. Simultaneously, impressive developments in the field of elastan fibers and modern knitting and weaving technologies, offer chances for realization of completely new types of compression bandages, capable of making an important contribution to the management of venous disease. In this review, starting from the brief account of pathogenesis and the presentation of compression therapy principle, an account of the contribution of all sectors in the textile technological chain to a modern compression therapy is given.
Automatic production of double coated alginate microcapsules: Analysis of the experimental parameters by design of experiments
Authors: Mazzitelli Stefania , Luca Giovanni , Tosi Azzurra , Balestra Cosimo , Capretto Lorenzo , Nastruzzi Claudio
Published: March 2009

This paper describes a design of experiments (DoE) approach, of an automatic procedure for the microencapsulation of isolated neonatal porcine islets (NPI). Monodisperse droplets were prepared by a vibrational nozzle, using an alginate/polyornithine encapsulation procedure, that has been developed and validated in our laboratory to encapsulate pancreatic islets. Different experimental parameters were considered such as: frequency of vibration, amplitude of vibration, polymer pumping rate and distance between the nozzle and the gelling bath. The produced calcium-alginate gel microbeads displayed an excellent morphology as well as a very narrow size distribution. The automatically produced microcapsules did not alter morphology and viability and functional properties of the enveloped NPI. The optimization of this automatic procedure may provide a novel approach to obtain a large number of batches possibly suitable for large scale production of immunoisolated NPI for in vivo cell transplantation procedures in humans.
Fluid dynamics of gas - flowing solids - fixed bed contactors
Authors: Nikacevic Nikola , Dudukovic Aleksandar
Published: March 2009

Fluid dynamics studies of countercurrent gas - flowing solids - fixed bed contactors are presented in this review. The up-to-date research findings about the basic fluid dynamics parameters: flowing solids holdup, pressure drop and flow pattern are reviewed. Experimental results, as well as theoretical studies and mathematical models are observed and commented.
The kinetic models of the bioprocess with free and immobilized cells
Authors: Zerajic Stanko , Savkovic-Stevanovic Jelenka
Published: March 2009

The kinetic models are fundamental knowledge of biochemical and microbial processes. The aim of the work is the kinetic model research based on biochemical and microbial mechanisms of the cell growth, the substrate consumption and the product formation. The engineering goal is to obtain ethanol as a fuel from renewable resources by a biosynthesis process. The engineering goal requires the inclusion of the inhibitory effect of a high substrate and ethanol concentration in the kinetic models. The interactions of the ethanol synthesis with the growth biomass mechanism were researched. The models of the ethanol forming mechanisms were incorporated in the complex structure of the kinetic models. The researches of the kinetic models were realized by computer simulation and experimental verification at the ethanol biosynthesis process from glucose with free and immobilized cells Saccharomyces cerevisiae. The model parameters and the limits were estimated by experimental validation. The base of the verified deterministic and semi-empiric kinetic models was created. The model base may be onward used for the process simulation models generating.
Comparison of EU framework and daughter directives and current Serbian legislation on air pollution monitoring
Authors: Jovasevic-Stojanovic Milena , Matic-Besarabic Snezana
Published: March 2009

This paper discusses the air quality control in the current legislation of the Republic of Serbia and compares it with the relevant EU legislation, Framework and Daughter Directives of the air quality monitoring and management. QA/QC components, instrumentation and methodologies of the air quality control in RS are not yet structured and harmonized with EU requirements. The limit and target values for air pollutants notified in EU legislation may be partly comparable with relevant requirements in RS legislation.
Synthesis, X-ray and antimicrobial activity of isatin-3-phenylhydrazone
Authors: Konstantinovic Sandra , Kapor Agnes , Radovanovic Blaga , Deak Andrea
Published: March 2009

Isatin-3-phenylhydrazone was synthesized and X-ray crystal structure of this compound has been solved. Its structure was also established using FTIR, UV/Vis and H-NMR spectroscopic method. The compound was tested for antimicrobial activity against Staphylococcus aureus, Bacillus subtilus, Enterococcus D, Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa and Candida albicans. Stability of isatin-3-phenylhydrazone toward UV-A irradiation has been studied in this work. Isatin derivative undergoes bleaching following first-order kinetics.
The influence of tartaric acid on the phenomena of Al(OH)3 crystallization from the caustic soda solution
Authors: Nikolic Irena , Blecic Dragoljub , Blagojevic Nada
Published: March 2009

Crystallization of Al(OH)3 from the caustic soda solution is the most important part of the Bayer process for alumina production because several phenomena which determine the properties of precipitated Al(OH)3 occur simultaneously. These processes are nucleation, agglomeration and Al(OH)3 growth. In this paper we have investigated the influence of tartaric acid on agglomeration, nucleation and Al(OH)3 crystal growth processes. The results have shown the inhibitory influence of these impurities on the phenomena mentioned above.
A microwave-assisted liquefaction as a pretreatment for the bioethanol production by the simultaneous saccharification and fermentation of corn meal
Authors: Nikolic Svetlana , Mojovic Ljiljana , Rakin Marica , Pejin Dusanka , Savic Dragisa
Published: March 2009

A microwave-assisted liquefaction as a pretreatment for the bioethanol production by the simultaneous saccharification and fermentation (SSF) of corn meal using Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. An optimal power of microwaves of 80 W and the 5-min duration of the microwave treatment were selected by following the concentration of glucose released from the corn meal suspensions at hidromodul of 1:3 (corn meal to water ratio) in the liquefaction step. The results indicated that the microwave pretreatment could increase the maximum ethanol concentration produced in the SSF process for 13.4 %. Consequently, a significant increase of the ethanol productivity on substrate (YP/S), as well as the volumetric ethanol productivity (P) in this process, could be achieved.
The immobilization of lipase on Sepabeads: Coupling, characterization and application in geranyl butyrate synthesis in a low aqueous system
Authors: Knezevic-Jugovic Zorica , Damnjanovic Jasmina , Bezbradica Dejan , Mijin Dusan
Published: March 2009

Lipase from Candida rugosa immobilized on Sepabeads EC-EP was shown to catalyze the esterification of geraniol with butyric acid in a predominantly organic system. The immobilization procedure was adjusted to optimize the enzyme activity and the immobilized enzyme was then used for a geranyl butyrate synthesis as a study model. The immobilized enzyme showed favorable performances in an aqueous system and increased the stability in the presence of organic solvents. The response surface methodology and a 5-level-5-factor central composite rotatable design were performed to identify the factors that influence the ester production and to verify whether any changes should be made in their settings to improve this reaction. The initial water content, the reaction temperature, the enzyme concentration, acid/alcohol molar ratio and time of addition of molecular sieves were the variables investigated. The production of the ester was optimized and an ester production response equation was obtained, making it possible to predict ester yields from the known values of the five main factors. The temperature during the esterification reaction was identified as the factor having the greatest impact on the ester yield.
In situ lead stabilization using natural and synthetic apatite
Authors: Kaludjerovic-Radoicic T. , Raicevic S.
Published: March 2009

In this work, mineral apatite was investigated for the remediation of lead contamination. Two different apatite minerals were used: synthetic apatite, Ca10(PO4)6(OH)2 (hereafter denoted as HAP) and natural apatite from Lisina, near Bosilegrad, Serbia (hereafter denoted as LA). Phosphate ore from Lisina deposit consists of 43.3 % apatite in the form of fluorapatite, Ca10(PO4)6(F)2. Sorption properties of HAP and LA were investigated. The results show that both of these minerals are effective in lead removal from the water solution. Sorption capacity of HAP obtained in this experiment is 0.216 mmol Pb/g HAP, while the value for LA is 0.162 mmol Pb/g LA. Modeling of these systems was conducted using Visual Minteq computer program. The values obtained from the computer simulation were compared to experimental values.
Investigating the influence of nanoadhesion on strength properties of high-strength organic fibres and organoplastics based on them
Authors: Burya A.I. , Cherkasova N.G. , Kirpich V.V.
Published: March 2009

The tensile, thermophysical and tribotechnical characteristics of organoplastics based on thermosetting matrix chaotically reinforced with discrete highly tensile organic fiber have been investigated, and the efficiency of nano-additions introduced both into the polymer matrix and as fibre finish is shown in this paper.