bluuebunny/crossref_metadata_2025 huggingface dataset:
Organizational institutionalism in the academic field in Brazil: social dynamics and networks
Authors: Guarido Filho Edson Ronaldo , Machado-da-Silva Clóvis L. , Gonçalves Sandro Aparecido
Published: November 2010

This article is based on the assumption that the construction of scientific knowledge is a social process characterized by the recursive dynamic between the social and intellectual dimensions. In light of this statement, we investigated how the construction of the institutional perspective is delineated in the context of organizational studies in Brazil from 1993 to 2007. The study is based on documentary research of articles published in scientific journals and at academic events. For this purpose, we analyzed social networks and used bibliometric indicators in order to map the cooperation relationships between researchers and intellectual framework, based on the cited authors. The results show the influence of social relationships in the process of constructing scientific knowledge. The findings reveal that the expansion of the field is based on the growing elaboration of a social organization with close links to the activities of continuant and transient researchers. These circumstances denote the stratification both of production and the relationships between authors, since continuant and transient researchers are responsible for the intermediation of relations and the consolidation of production in the academic field that is being analyzed. The findings also reveal a secondary dynamic of the activities of researchers located on the margin of the network and the presence of Brazilian researchers among the most cited authors, an indication of a legitimized local intellectual base.
Combined effects of heat waves and droughts on avian communities across the conterminous United States
Authors: Albright Thomas P. , Pidgeon Anna M. , Rittenhouse Chadwick D. , Clayton Murray K. , Wardlow Brian D. , Flather Curtis H. , Culbert Patrick D. , Radeloff Volker C.
Published: November 2010

Increasing surface temperatures and climatic variability associated with global climate change are expected to produce more frequent and intense heat waves and droughts in many parts of the world. Our goal was to elucidate the fundamental, but poorly understood, effects of these extreme weather events on avian communities across the conterminous United States. Specifically, we explored: (1) the effects of timing and duration of heat and drought events, (2) the effects of jointly occurring drought and heat waves relative to these events occurring in isolation, and (3) how effects vary among functional groups related to nest location and migratory habit, and among ecoregions with differing precipitation and temperature regimes. Using data from remote sensing, meteorological stations, and the North American Breeding Bird Survey, we used mixed effects models to quantify responses of overall and functional group abundance to heat waves and droughts (occurring alone or in concert) at two key periods in the annual cycle of birds: breeding and post‐fledging. We also compared responses among species with different migratory and nesting characteristics, and among 17 ecoregions of the conterminous United States. We found large changes in avian abundances related to 100‐year extreme weather events occurring in both breeding and post‐fledging periods, but little support for an interaction among time periods. We also found that jointly‐, rather than individually‐occurring heat waves and droughts were both more common and more predictive of abundance changes. Declining abundance was the only significant response to post‐fledging events, while responses to breeding period events were larger but could be positive or negative. Negative responses were especially frequent in the western U.S., and among ground‐nesting birds and Neotropical migrants, with the largest single‐season declines (36%) occurring among ground‐nesting birds in the desert Southwest. These results indicate the importance of functional traits, timing, and geography in determining avian responses to weather extremes. Because dispersal to other regions appears to be an important avian response, it may be essential to maintain habitat refugia in a more climatically variable future.
Intramarrow Bone Morphogenetic Protein 4 Gene Delivery Improves Local Bone Quality in Femurs of Ovariectomized Rabbits
Authors: Hsiao Wen‐Kai , Yew Tu‐Lai , Lai Yu‐Lin , Lee Shyh‐Yuan , Chen Hen‐Li
Published: November 2010

Background: Poor bone quality at implant recipient site is a major risk factor for implant failure. The purpose of this study is to examine the potential of intramarrow bone morphogenetic protein 4 (BMP4) gene delivery for local bone quality improvement.

Methods: Adenoviral vector encoding human BMP4 (Ad‐BMP4) was constructed. Adenovirus encoding β‐galactosidase (Ad‐LacZ) was used as a control virus. Ad‐BMP4 and Ad‐LacZ were injected into femurs of ovariectomized rabbits. The temporal changes in bone mineral density at injected areas were determined by repeated measurements by dual‐energy x‐ray absorptiometry at 0, 1, 2, 4, and 8 weeks after injection. The effects of gene delivery on cortical bone and cancellous bone were evaluated by microcomputed tomography analysis and histologic examination at 8 weeks.

Results: The bone mineral density of the BMP4 group was significantly higher than the LacZ group at 4 and 8 weeks by 61% and 35%, respectively. Results from microcomputed tomography analysis and histologic examination at 8 weeks indicated thicker cortical bone and denser cancellous bone in the BMP4 group compared to the LacZ group.

Conclusions: Intramarrow gene delivery of BMP4 effectively improved local bone quality for at least 8 weeks. The sustained delivery of osteogenic factors via local gene therapy approach may reduce implant failures associated with poor local bone quality.
Acute Myocardial Infarction is Reflected in Salivary Matrix Metalloproteinase‐8 Activation Level
Authors: Buduneli Eralp , Mäntylä Päivi , Emingil Gülnur , Tervahartiala Taina , Pussinen Pirkko , Barış Nezihi , Akıllı Azem , Atilla Gül , Sorsa Timo
Published: November 2010

Background: The aim of this study is to compare salivary and serum biomarker levels and degrees of matrix metalloproteinase (MMP) activation between patients with acute myocardial infarction (AMI) and systemically healthy patients (non‐AMI) with similar periodontal conditions.

Methods: A total of 92 patients (47 AMI and 28 non‐AMI patients with gingivitis or periodontitis; and 17 systemically and periodontally healthy patients as a control group) were recruited. Clinical periodontal measurements were recorded; stimulated whole saliva and serum samples were collected. AMI patients were clinically examined within 3 to 4 days after admission to the coronary care unit. Saliva samples were analyzed for levels of MMP‐8, MMP‐7, and tissue inhibitor of matrix metalloproteinase (TIMP)‐1. Serums were tested for MMP‐8, MMP‐9, TIMP‐1, and TIMP‐2 levels by immunofluorometric assay and enzyme‐linked immunosorbent assay. Molecular forms and degree of activation of salivary MMP‐8, MMP‐9, and MMP‐13 were analyzed by computer‐scanned immunoblots.

Results: Total salivary MMP‐8 assessed by immunofluorometric assay method and immunoblot densitometric units was higher in non‐AMI than in AMI patients' saliva but a significantly higher percentage of AMI patients was activated polymorphonuclear leukocyte type (PMN) MMP‐8 (P <0.001) regardless of periodontal diagnosis. Serum MMP‐8, MMP‐9, and TIMP‐1 levels were significantly higher in AMI (for all markers and all comparisons, P <0.05). Characteristic for AMI was dominance of active PMN MMP‐8 in saliva.

Conclusions: Enhanced MMP‐8 activation in the saliva of AMI patients is evidently, in part, of systemic origin. Consequently, AMI is reflected in serum but also in saliva.
Interleukin‐8 Gene Promoter Polymorphism (rs4073) May Contribute to Chronic Periodontitis
Authors: Andia Denise C. , de Oliveira Naila F. P. , Letra Ariadne M. , Nociti Francisco H. , Line Sergio R. P. , de Souza Ana P.
Published: November 2010

Background: The proinflammatory chemokine interleukin (IL)‐8 is important in the regulation of the inflammatory response. Analyses of the single nucleotide polymorphism (SNP) reference sequence (rs) 4073 showed that the A allele upregulated IL‐8 levels after stimulation with lipopolysaccharides. We investigated the association of the SNP rs4073 with chronic periodontitis.

Methods: Genotyping was performed by a standard polymerase chain reaction–restriction fragment length polymorphism assay in 289 genomic DNA samples of healthy control subjects and patients with chronic periodontitis; analyses were adjusted by multivariate logistic regression modeling. A real‐time polymerase chain reaction performance was used to detect levels of the IL‐8 mRNA.

Results: The analysis pointed to a statistically significant association of chronic periodontitis with the heterozygous TA genotype (P = 0.001); the results showed an increase in the frequency of the A allele in the diseased group (36% in the control group versus 48% in the periodontitis group). The higher levels of the IL‐8 mRNA were found in the periodontitis group, mainly in individuals who presented the TA genotype (P = 0.03).

Conclusion: The SNP rs4073 was associated with chronic periodontitis in non‐smoker Brazilian subjects because the frequency of the A allele was higher in the disease group than in the control group, and the TA genotype was associated with increased levels of IL‐8 mRNA transcripts.
Geosmin and 2-methylisoborneol adsorption on super-powdered activated carbon in the presence of natural organic matter
Authors: Matsui Y. , Nakano Y. , Hiroshi H. , Ando N. , Matsushita T. , Ohno K.
Published: November 2010

Geosmin and 2-methylisoborneol (2-MIB) are naturally occurring compounds responsible for musty-earthy-odors in surface water supplies. They are a severe problem confronting utilities worldwide. Adsorption by powdered activated carbon (PAC) is a widely used process to control this problem, but it has low efficiency, which engenders large budget spending for utilities services. Super-powdered activated carbon (S-PAC) is activated carbon with much finer particles than those of PAC. Experiments on geosmin and 2-MIB adsorptions on S-PAC and PAC were conducted. Geosmin and 2-MIB adsorption capacities on S-PAC were not smaller than those on PAC although natural organic matter, which adversely impacted the adsorption capacity of geosmin and 2-MIB, was more adsorbed on S-PAC than on PAC, meaning that the adsorption competition is less severe for S-PAC than for PAC.
Subsurface iron and arsenic removal: low-cost technology for community-based water supply in Bangladesh
Authors: van Halem D. , Heijman S. G. J. , Johnston R. , Huq I. M. , Ghosh S. K. , Verberk J. Q. J. C. , Amy G. L. , van Dijk J. C.
Published: November 2010

The principle of subsurface or in situ iron and arsenic removal is that aerated water is periodically injected into an anoxic aquifer through a tube well, displacing groundwater containing Fe(II). An oxidation zone is created around the tube well where Fe(II) is oxidised. The freshly formed iron hydroxide surfaces provide new sorption sites for soluble Fe(II) and arsenic. The system's efficiency is determined based on the ratio between abstracted volume with reduced iron/arsenic concentrations (V) and the injected volume (Vi). In the field study presented in this paper, the small-scale application of this technology was investigated in rural Bangladesh. It was found that at small injection volumes (<1 m3) iron removal was successful and became more effective with every successive cycle. For arsenic, however, the system did not prove to be very effective yet. Arsenic retardation was only limited and breakthrough of 10 μg/L (WHO guideline) was observed before V/Vi=1, which corresponds to arrival of groundwater at the well. Possible explanations for insufficient arsenic adsorption are the short contact times within the oxidation zone, and the presence of competing anions, like phosphate.
Evaluation of manganese peroxidase (MnP) for its ability to resist the ozonization and thereafter decolorize methyl orange
Authors: Cheng Zhou , Xiang-hua WEN , Xi Zhao
Published: November 2010

The goal of this study was to determine whether ozone can be used to suppress bacterial growth in operating a white rot fungi reactor system. The effects of ozone dose on the activity of manganese peroxidase (MnP) and on the death rate of Escherichia coli were investigated. The results showed that at ozone dose of 0.98 mg/L the MnP activity was not affected after 40 min continuous treatment while the Escherichia coli inactivation rate can reach 99.9% after 30 min; In addition, the MnP that exposed to ozone dose of 1.56 mg/L for 40 min maintained their activity for decolourization of Methyl Orange. After 16 h, the decolorization rate of Methyl Orange was about 41%. These results showed that MnP have the ability to resist to some extent the attack of ozonization, which suggest that ozone might have its potential in suppressing the bacteria contamination in operating the white rot fungi reactor.
Oxidation of acetyl-pyrimidine wastewater by Fenton process
Authors: Yi Xuesong , Sun Liping , Yu Jingjie , Wang Shaopo , Yu Shuili
Published: November 2010

In this study, contaminant degradation, priority performance, intermediates, and kinetics in catalytic oxidation of Acetyl-Pyrimidine wastewater by Fenton reagent were investigated. In batch experiments, the main parameters that govern the complex reactive system, i.e. temperature, pH, Fe2 + , and H2O2 initial concentrations have been studied. The results showed total COD and Acetyl-Pyrimidine removal was above 50% and 90% respectively under the following oxidation conditions: T at 25°C, pH at 3.5, H2O2 at 300 mmol/l, Fe2 +  at 40 mmol/l, with the reaction time 2 h. Control experiment and UV-Infrared spectrums analysis indicated that Acetyl-Pyrimidine was removed prior to the small molecule organic. The reaction fit to a first-order rate equation and the activation energy of Pyrimidine was 2.365 kJ/mol.
Synthesis and characterization of composite polysulfone membranes for desalination in nanofiltration technique
Authors: Akbari A. , Homayonfal M. , Jabbari V.
Published: November 2010

Composite nanofiltration (NF) membrane was developed polyacrylic acid (PAA) in situ UV graft polymerization process using ultrafiltration (UF) polysulfone (PSF) membrane as porous support. FT-IR spectra indicated that grafting was performed and it show peaks at 1,732 cm−1 and 3,396 cm−1 region for CO and OH starching bond of acrylic acid (AA) monomer, respectively. AFM microscopy showed the roughness of surface was reduced by increase of UV irradiation times. Effect of irradiation time on the grafting of acrylic acid (AA) in the same concentration was discussed. The salts rejection increase was accompanied with grafting of polysulfone (PSF) ultrafiltration (UF) membrane. The rejection of Na2SO4, MgSO4, NaCl and CaCl2 salts by PSF-grafted-PAA nanofiltration (NF) membrane was in 98, 60, 52 and 30% respectively, under 0.3 MPa.
Activated bauxite waste as an adsorbent for removal of Acid Blue 92 from aqueous solutions
Authors: Norouzi Sh. , Badii Kh. , Doulati Ardejani F.
Published: November 2010

Bauxite waste, known as red mud, is produced in some industrial processes, such as aluminum production process. In this process, the waste material is produced from leached bauxite as a by product. In this research, the removal of Acid Blue 92 (AB92) dye was investigated from aqueous solution onto the activated bauxite waste (red mud) in a batch equilibration system. Besides, the influences of pH, adsorbent dosage, contact time, initial concentration of dye and temperature have been considered. It was found that the OH group is an effective functional group for the adsorption process. The intensity of the peaks correspond to OH group has been significantly climbed after the activation process. The adsorption kinetics of AB92 can be well described by the pseudo-second-order reaction model. Based on the isotherm data obtained from the fittings of the adsorption kinetics, the Langmuir model appears to fit the adsorption process better than the Freundlich and Brunauer-Emmett-Teller (BET) models.
Source of N-nitrosodimethylamine in river waters of the upper Tone River basin in Japan
Authors: Kosaka K. , Fukui K. , Asami M. , Akiba M.
Published: November 2010

The presence of N-nitrosodimethylamine (NDMA) in the Hirose River and its tributaries, located in the upper Tone River basin, in the Kanto region of Japan, was investigated. NDMA was detected at high levels in the Arato River, one of the tributaries of the Hirose River, at high concentrations (up to 2,100 ng/L). Due to the confluence of the Arato River, NDMA concentration in the Hirose River increased (up to 61 ng/L). The NDMA in the Arato River was due to industrial discharge from a livestock processing plant located near the river. There were three discharges at the plant, with NDMA concentrations of 78, 11, and 33,000 ng/L. The industrial discharges from the livestock processing plant did not contain significant amounts of NDMA precursors on chloramination. On the other hand, sewage effluent was shown to contain NDMA precursors. The amounts of NDMA precursors in the sewage effluent that were rapidly transformed into NDMA were considered to be lower than those slowly transformed into NDMA.
Sensitivity analysis using a diffuse pollution hydrologic model to assess factors affecting pesticide concentrations in river water
Authors: Tani Koji , Matsui Yoshihiko , Narita Kentaro , Ohno Koichi , Matsushita Taku
Published: November 2010

We quantitatively evaluated the factors that affect the concentrations of rice-farming pesticides (an herbicide and a fungicide) in river water by a sensitivity analysis using a diffuse pollution hydrologic model. Pesticide degradation and adsorption in paddy soil affected concentrations of the herbicide pretilachlor but did not affect concentrations of the fungicide isoprothiolane. We attributed this difference to the timing of pesticide application in relation to irrigation and drainage of the rice paddy fields. The herbicide was applied more than a month before water drainage of the fields and runoff was gradual over a long period of time, whereas the fungicide was applied shortly before drainage and runoff was rapid. However, the effects of degradability-in-water on the herbicide and fungicide concentrations were similar, with concentrations decreasing only when the rate constant of degradation in water was large. We also evaluated the effects of intermittent irrigation methods (irrigation/artificial drainage or irrigation/percolation) on pesticide concentrations in river water. The runoff of the fungicide, which is applied near or in the period of intermittent irrigation, notably decreased when the method of irrigation/artificial drainage was changed to irrigation/percolation. In a sensitivity analysis evaluating the synergy effect of degradation and adsorbability in soil, the degradation rate constant in soil greatly affected pesticide concentration when the adsorption coefficient was small but did not affect pesticide concentration when the adsorption coefficient was large. The pesticide concentration in the river water substantially decreased when either or both the degradation rate constant in soil and adsorption coefficient was large.
Screening of pharmaceuticals and endocrine disrupting compounds in water supplies of Cyprus
Authors: Makris Konstantinos C. , Snyder Shane A.
Published: November 2010

Cyprus is currently the leading country in antibiotic consumption among all European Union member countries and is likely to have a high consumption of pharmaceuticals overall. This reconnaissance type of project sought to investigate the occurrence of 16 pharmaceuticals, six known or suspected endocrine disrupting compounds (EDCs), two flame retardants, one insect repellant, and one fragrance for the first time in water supplies of Cyprus. Groundwater samples from sites that were located beneath farms scattered around Cyprus, wastewater influent and tertiary-treated effluent, raw and finished surface water, and household potable water samples were analyzed using liquid chromatography and tandem mass spectrometry. Most of the tested compounds were < minimum reporting limit, except for ibuprofen (mean of 1.4 ng L−1) and bisphenol A (mean of 50 ng L−1), which were detected in more than one out of the five groundwater sampling sites. Certain compounds were found in large concentrations in the wastewater influent (caffeine 82,000 ng L−1, sulfamethoxazole 240 ng L−1, ibuprofen 4,300 ng L−1, and triclosan 480 ng L−1). However, several pharmaceuticals and EDCs were detected in the tertiary-treated effluent (recycled water). For the raw and finished surface water, and potable water samples, ibuprofen was detected, whereas, bisphenol-A was measured in only potable water. Overall, with a few notable exceptions, source, finished and potable water had rare detection or low concentration of target compounds, but further research is needed to elucidate the temporal and spatial distribution of the detected emerging contaminants along with the characterization of the related public health risk.
Integrated approach for biofouling control
Authors: Vrouwenvelder J. S. , Kruithof J. C. , Van Loosdrecht M. C. M.
Published: November 2010

Despite extensive research efforts, past and present strategies to control biofouling problems in spiral-wound nanofiltration and reverse osmosis membranes have not been successful under all circumstances. Gaining insight in the biofouling process is a first necessity. Based on recent insights, an overview is given of 12 potential complementary approaches to solve biofouling. Combinations of approaches may be more efficient in biofouling control than a single approach. A single approach must be 100% effective, while in combination each individual approach can be partially effective while the combination is still efficient. An integrated Approach for Biofouling Control (ABC) is proposed, based on three corner stones: (i) equipment design and operation, (ii) biomass growth conditions, and (iii) cleaning agents as a framework to control biofouling. While past and present strategies addressed mainly membranes and microorganisms, i.e. removal or inactivation of biomass, this ABC-approach addresses the total membrane filtration system. It is anticipated that this integral approach will enable a more rational and effective control of biofouling. Although in this stage chemical cleaning and biofouling inhibitor dosage seem unavoidable to control biofouling, it is expected that in future—because of sustainability and costs reasons—membrane systems will be developed without or with minimal need for chemical cleaning and dosing. Three potential scenarios for biofouling control are proposed based on (i) biofouling tolerant spiral wound membrane systems, (ii) capillary membranes, and (iii) phosphate limitation.
The qualitative determination of oseltamivir phosphate in Tamiflu® capsule by cyclic voltammetry
Authors: Avramov-Ivic Milka , Petrovic Slobodan , Mijin Dusan , Drljevic-Djuric Katica
Published: November 2010

A gold electrode was applied in the voltammetric determination of oseltamivir
phosphate standard in 0.05 M NaHCO3. Oseltamivir phosphate as a standard and
as a component of Tamiflu? capsule exhibited the identical cyclic
voltammogram. The peaks originated from excipients in capsule do not appear
under the applied electrochemical conditions. The electrochemical method for
the qualitative determination of oseltamivir phosphate in Tamiflu? capsule by
cyclic voltammetry was developed. The presence of oseltamivir phosphate as
standard and as a content of Tamiflu? capsule in electrolyte as well as their
concentrations were simultaneously checked by HPLC. The lack of the
current/concentration dependency was established. The not pretreated glassy
carbon electrode cannot be used for the determination of oseltamivir
phosphate under identical experimental conditions presented for gold
electrode.
A contribution to the study of hydrophobicity (lipophilicity) of bile acids with an emphasis on oxo derivatives of 5β-cholanoic acid
Authors: Posa Mihalj , Raseta Milena , Kuhajda Ksenija
Published: November 2010

Due to their promotory action on the transport of some drugs through various
membranes (lipophilic barriers), oxo derivatives of bile acids have recently
been increasingly used in biopharmacy. These compounds exhibit also a lower
membranolytic (toxic) activity than their hydroxy analogues. Because of that
it is of special importance to find out the descriptors that would adequately
describe the structure of bile acids and their biological activity and be
used to model the quantitative structure-activity relationship. In view of
this, the present work is concerned with the application of the
chromatographic parameter RM0 obtained by normal-phase thin-layer
chromatography in the solvent system toluene-butanol and silica gel as
stationary phase to describe the lipophilicity of bile acids. Also, the work
introduces a new molecular descriptor (ND) that reflects both 2D and 3D
topological characteristics of the molecule. Between the retention constant,
RM0 and the descriptor ND there is a good correlation, and both RM0, and ND
describe sufficiently well the structural (conformational) changes that arise
in the process of oxidation of the OH group of the steroid skeleton to an oxo
group. On the other hand, the in silico descriptors of lipophilicity, logP
(atomic-based prediction) and ClogP (fragment-based prediction) predict the
hydrophobicity of bile acid oxo derivatives with a certain error.
Interaction mechanism between refractory and melts in iron bath smelting reduction process
Authors: Qiu G.B. , Xu Y.
Published: November 2010

The corrosion behavior of three sorts of refractories based on
alumina-graphite were studied by immersion tests. The melts included smelting
reduction molten slag and corresponding carbon saturated molten iron. The
influence of test temperature, FeO content in slag and specimen rotative
velocity on the corrosion rate of refractories was examined. By means of SEM
and EDS, the microstructure change of the refractories after immersion test
in kinds of melts was studied. The morphology of the deteriorated layer
showed the corrosion extent of refractories. With the addition of zirconia
and titania into the refractories, the corrosion rate changed to some extent.
The corrosion rate of three sorts of refractories increased dramatically with
the increasing FeO content in smelting reduction slag. Compared with
alumina-graphite refractory and alumina-graphite-zirconia refractory,
alumina-graphite-titania refractory had stronger corrosion resistance in the
smelting reduction conditions. By the results of SEM and EDS, the corrosion
mechanism of refractories was developed.
Calculated mixing enthalpies of 11 IIB-IVB and IIB-VB binary alloy systems using a subregular model
Authors: Bangwei Z. , Xiaolin S. , Shuzhi L. , Xiaojian Y. , Haowen X.
Published: November 2010

There have been no theoretical calculations of the mixing enthalpies for
group B metal alloy systems using the famous Miedema theory or from first
principles. Therefore such systematic calculations for the 11 group IIB?IVB
and IIB?VB binary alloy systems are performed for the first time using a
subregular model. The results show that the agreement between the
calculations and experimental data is pretty good and could be accepted from
the theoretical or experimental points of view. It can be concluded from the
results that the subregular model can be used for calculating the mixing
enthalpies of the group B alloy systems, at least for the IIB?IVB and IIB?VB
alloy systems.
Precipitation sequence of an aged Al-Mg-Si alloy
Authors: Fang X. , Song M. , Li K. , Du Y.
Published: November 2010

Heat treatable Al-Mg-Si alloys can be strengthened via the precipitation of
metastable phase particles. The precipitation sequence of an Al-0.89Mg-0.75Si
alloy with trace Fe and Zn elements during aging at 180 ?C has been
investigated by transmission electron microscope (TEM), high resolution
transmission electron microscope (HRTEM) and hardness measurements. It has
been shown that the precipitation sequence of the alloy can be identified as
follows: supersaturated solid solution ? G.P. zones ? metastable ??
precipitates ? metastable ?? precipitates ? stable ? phase + Si particles. It
is indicated that ?? phase remains stable up to 30 hours at 180?C. The
hardness measurements during aging realize that the main strengthening phase
for the investigated Al-Mg-Si alloy is ?? precipitates and the maximum
hardness is obtained after aging at 180 ?C for 4~6.5 hours.
Protection of segetal flora and vegetation in Poland (historical outline)
Authors: Siciński Jan , Sieradzki Jarosław
Published: November 2010

Protection of segetal flora and vegetation in Poland (historical outline)

The flora associated with crop land maintained a stable species composition for many centuries until the 1960s when profound and fast changes occured due to human activity. Factors that destructively affect given species, but also whole field communities, are: continuous chemicalization of agriculture (i.e. application of crop protection substances, pesticides, and mainly herbicides, as well as spreading of high doses of mineral fertilizers on crop land), introduction of sewing material that is completely purified from weed seeds, introduction of new races of crop plants, simplification of crop rotation patterns, introduction of new techniques of soil and plant cultivation and draining of cultivated fields. These factors have caused various transformations of the field flora, often abruptly and chaotically, such as the disappearance of numerous weed species. The rate of these transformations varies from country to country, region to region, and even field to field. These facts have made numerous investigators pay much interest to the conservation of the segetal flora, both in cultivated land and in preserved areas, such as national and landscape parks, botanical gardens and open-air museums. The problem of transformations in the segetal flora vegetation is a very important one both from the utilitarian and ‘nature conservation’ point of view.
Robust output predictive sequential controller design
Authors: Veselý Vojtech , Rosinová Danica
Published: November 2010

Robust output predictive sequential controller design

The paper addresses design problem of a robust parameter dependent quadratically stabilizing output/state feedback model predictive control for linear polytopic systems without constraints using original sequential approach. The design procedure ensures stability, robustness properties and guaranteed cost for the closed-loop uncertain system.
Continuous-time dynamic system identification with multisine random excitation revisited
Authors: Figwer Jarosław
Published: November 2010

Continuous-time dynamic system identification with multisine random excitation revisited

The paper presents a new, revisited and unified approach to a linear continuous-time dynamic single-input single-output system identification using input and output signal samples acquired with a deterministic constant or random sampling interval. The approach is based on a specially designed identification experiment with excitation of the form of a continuous-time multisine random excitation and digital processing of the corresponding signal samples obtained without analogue antialiasing filtration in the case of disturbances satisfying or not satisfying the Shannon's sampling theorem. Properties of the proposed approach are discussed taking into account nonlinearity of the excitation generation and data acquisition systems with a focus on model identification in the case of input and output signal levels comparable with data acquisition system accuracy. Methods reducing influence of the disturbances (including aliasing) as well as nonlinearities of the excitation generation and data acquisition systems on identification results are proposed, too.
Exponential stability of networked control systems with network-induced random delays
Authors: Krokavec Dusan , Filasová Anna
Published: November 2010

Exponential stability of networked control systems with network-induced random delays

In this paper, the problem of exponential stability for the standard form of the state control, realized in a networked control system structure, is studied. To deal with the problem of stability analysis of the event-time-driven modes in the networked control systems the delayed-dependent exponential stability conditions are reformulated and proven. Based on the delay-time dependent Lyapunov-Krasovskii functional, exponential stability criteria are derived. These criteria are expressed as a set of linear matrix inequalities and their structure can be modified to use the bilinear inequality techniques.
Decomposition of the pairs (A, B) and (A, C) of positive discrete-time linear systems
Authors: Kaczorek Tadeusz
Published: November 2010

Decomposition of the pairs (A, B) and (A, C) of positive discrete-time linear systems

A new test for checking the reachability (observability) of positive discrete-time linear systems is proposed. Conditions are established under which the unreachable pair (A, B) and the unobservable pair (A, C) of positive discrete-time system can be decomposed into reachable and unreachable parts and observable and unobservable parts, respectively. It is shown that the transfer matrix of the positive system is equal to the transfer matrix of its reachable (observable) part.
Stator inter-turn fault detection of an induction motor using neuro-fuzzy techniques
Authors: Dash Rudra , Subudhi Bidyadhar
Published: November 2010

Stator inter-turn fault detection of an induction motor using neuro-fuzzy techniques

Motivated by the superior performances of neural networks and neuro-fuzzy approaches to fault detection of a single phase induction motor, this paper studies the applicability these two approaches for detection of stator inter-turn faults in a three phase induction motor. Firstly, the paper develops an adaptive neural fuzzy inference system (ANFIS) detection strategy and then compares its performance with that of using a multi layer perceptron neural network (MLP NN) applied to stator inter-turn fault detection of a three phase induction motor. The fault location process is based on the monitoring the three phase shifts between the line current and the phase voltage of the induction machine.
Detecting Voids under Pavements
Authors: Malvar L. J.
Published: November 2010

Several accidents involving aircraft punching through airfield pavements prompted the U.S. Navy to develop a technology for void detection. Initially, a successful void detection survey was completed at a naval air station where several voids were generated by leakage of large underground drainpipes. Various methods were used, such as internal videotaping of the pipes, heavy weight deflectometer (HWD) testing, testing with a ground-penetrating radar, and testing with a dynamic cone penetrometer (DCP). A state-of-the-art review was also completed to assess all existing technology applicable to void detection under pavements. However, the optimum technology (visual inspection and testing with an HWD and a DCP) still presented limitations because of the availability and speed of data acquisition, requiring prioritization of the work. A risk analysis was then completed and established work prioritization within each airfield and providing a prioritization of all U.S. Navy and Marine Corps airfield pavements. An interim policy and technical guidance (IP&TG) was issued on March 23, 2000, to establish the void detection methodology developed. This IP&TG was recently updated and included as an appendix in U.S. Department of Defense Unified Facilities Criterion UFC 3-260-03 and routinely applied at all 70 major U.S. Navy and Marine Corps airfields. This paper summarizes the methodology used and presents some recent field cases.
Development of Maintenance Strategies to Mitigate Bridge End Damage from Water Intrusion
Authors: Mishra Debakanta , Jayawickrama Priyantha W. , Nash Phillip T.
Published: November 2010

Significant amounts of money are spent annually on the rehabilitation of damaged pavements and approach slabs near bridge ends. Investigation of such failures often reveals that saturated base and subgrade materials or the loss of soil material from underneath the approach slab, pavement, or rip-rap slabs have contributed to failure. This paper reports findings from a research study entitled Water Intrusion in Base–Subgrade Materials at Bridge Ends. The objectives of this research project were to identify potential sources of water intrusion at bridge ends and develop maintenance strategies that can be economically implemented in the field to minimize future occurrences of the problem. The study focused on existing, in-service bridges and remedial strategies that have been successfully implemented. A survey questionnaire was developed and sent to all 25 Texas Department of Transportation administrative districts to collect information about the major factors contributing to water intrusion and bridge-end settlement problems. Field evaluations of selected bridges in four Texas DOT districts were conducted, and one bridge site was selected for detailed field study. On the basis of the information collected, the researchers developed a site assessment protocol to evaluate the potential of a particular site to incur water intrusion and methods to develop optimum repair strategies. The paper reports on the commonly observed sources of water intrusion at the bridge sites investigated. It also lists the preventive maintenance steps that must be taken to ensure that bridge approach pavements have adequate service lives.
Prediction of Subgrade Resilient Modulus Using Genetic Algorithm and Curve-Shifting Methodology
Authors: Coleri Erdem , Guler Murat , Gungor A. Gurkan , Harvey John T.
Published: November 2010

This paper demonstrates the applicability of the genetic algorithm and curve-shifting methodology to the estimation of the resilient modulus at various stress states for subgrade soils by using the results of triaxial resilient modulus tests. This innovative methodology is proposed as an alternative to conventional nonlinear constitutive relationships. With the genetic algorithm, laboratory curves for different deviator stress levels at different confining pressures are horizontally shifted to form a final gamma distribution curve that can represent the stress–strain behavior of subgrade soils with the corresponding predicted shift factors. Resilient modulus values for a given stress state can be estimated on the basis of this curve and another gamma function that represents the variation of the shift values for different confining stresses. To compare the effectiveness of these two approaches, coefficients for the Uzan constitutive model were also determined for each laboratory test and compared with those determined by the approach described in this paper. Predicted resilient modulus values from each approach are separately compared with artificial neural network (ANN) model predictions to evaluate their efficiency and reliability for resilient response prediction. The results of the analysis indicated that the curve-shifting methodology gave superior estimates and a coefficient of determination 14% higher than the Uzan model predictions when the results were evaluated with the ANN model outputs. Thus, although it is not a constitutive model, use of the genetic algorithm and curve-shifting methodology is proposed as a promising technique for the evaluation of the stress–strain dependency of subgrade soils.
Proposed Test Protocol for Evaluating Performance of Sediment Control Devices for Roadside Storm Water Runoff
Authors: McFalls Jett , Desai Aditya Raut , Foster Derrold , Li Ming-Han
Published: November 2010

This paper details an official testing program developed by researchers at the Texas Transportation Institute (TTI) to classify sediment retention devices on the basis of their sediment removal performance. The testing facility designed as part of this study was constructed at the Texas Department of Transportation–TTI Hydraulics, Sedimentation, and Erosion Control Laboratory (HSECL) located at the Texas A&M University Riverside Campus. The facility consists of a parabola-shaped testing channel 4.6 m (15 ft) wide and 5.5 m (18 ft) long with a maximum depth of 0.8 m (2.5 ft) at the center and a slope of 3%. Two commercially available artificial sediments were mixed in equal proportions to create the artificial storm water for testing. The flow rate and turbidity of the water entering and leaving the channel were monitored for the duration of the test. The turbidity measurements were converted to suspended solid concentration by using a relationship developed in the HSECL laboratory. A simple mass balance calculation was used to determine the amount of sediment trapped in the channel.
Effect of Nondurable Material on Settlement of Embankments
Authors: Vallejo Luis E. , Pappas Deno
Published: November 2010

Sedimentary rock fragments are used to build embankments. The fragments are made of durable and nondurable rocks. Durable rocks are defined as those that do not slake in the presence of water. In embankments, nondurable rock fragments are subjected to (a) compressive contact forces induced by other fragments and (b) slaking when they come into contact with water. These two processes convert the nondurable rock fragments into soil that moves into the space between the durable rock fragments, causing the settlement of the embankment. The goal of the present study was to calculate the amount of settlement experienced by a mixture of nondurable shale and durable limestone fragments when it is subjected to embankment loads. To this end, mixtures of the shale and limestone were placed in a metallic cylinder and subjected to three constant pressures. The settlement of the mixtures was measured at pressures equal to 345, 690, and 1,380 kPa. The settlements were measured first when the mixtures were dry. Then the mixtures were flooded with water, and the new settlements were recorded. The amount of settlement varied with the percentage by weight of the shale in the mixtures. The greatest settlements were recorded in the mixtures made of 100% shale. Small settlements were recorded when the mixtures were dry. Settlement was the result of the crushing and slaking of the shale fragments.
Design, Construction, and Performance of a Highway Embankment Failure Repaired with Tire-Derived Aggregate
Authors: Mills Bernie , McGinn Jared
Published: November 2010

In July 2006, a large embankment failure occurred during construction of a four-lane divided highway leading to the Canada–U.S. border crossing in St. Stephen, New Brunswick, Canada. The highway embankment was approximately 12.3 m in height, just short of the design height of 14 m, when it failed. The cause of the failure was attributed to the rapid rate of construction and the intensity of loading on low-strength foundation soils, consisting of up to 15 m of soft marine clay. The reconstruction effort used 1.4 million scrap tires to create the tire-derived aggregate (TDA) as lightweight fill. TDA was placed within the new embankment, constructed over the site of the original failure. An important element to the design was the installation of geotechnical instrumentation, which allowed an observational approach to be taken during the construction process. This approach resulted in modifications to the original design throughout the process of reconstructing the TDA embankment. This paper presents the results of the TDA embankment and foundation performance over 25 months, with an emphasis on the design and behavior of the TDA during construction. The predicted values versus the values measured in the field for geotechnical parameters and the performance characteristics of TDA are presented, including unit weight, temperature, immediate compression, and time-dependent compression. The values for these measured parameters are compared with those from similar case histories and published values available from the literature. The TDA embankment reconstruction project began in the summer of 2007 and was successfully completed in the late fall of 2008.
Medical education in Bangladesh - past, present and future
Authors: Abu Sayeed M
Published: November 2010

DOI: 10.3329/imcj.v4i2.6493Ibrahim Med. Coll. J. 2010; 4(2): i-ii
Waist-to-height ratio and socio-demographic characteristics of Bangladeshi adults
Authors: Flora Meerjady Sabrina , Mascie-Taylor CGN , Rahman Mahmudur
Published: November 2010

Anthropometric indicators of abdominal obesity are associated with cardiovascular risk factors, such as type 2 diabetes, hypertension, and dyslipidemia. Controversy remains regarding the best anthropometric indices for cardiovascular risk. Waist-to-height ratio has been reported to be an effective predictor of metabolic risks and it may be a better measure of relative fat distribution amongst subjects of different age and statures. Bangladeshi data lack in this perspective. To determine waist-to-height ratio of Bangladeshi adults along with its variation with socio-economic status, cross-sectional studies were conducted in 2002 and 2003. Data were collected through interviewing and measuring height and waist circumference of 22,995 adult males and females of an urban (Mirpur, Dhaka City) and rural area (Kaliganj sub-district). The mean waist-to-height ratio of 0.48 significantly varied with socio-demographic variables and it was markedly higher in females, older age groups, urban residents and the better educated. Urban residents, females, older people, better educational status, the non-paid and married individuals were more likely to have high waist-toheight ratio (≥0.5). High waist-to-height ratio levels using sex-specific cut-offs were more common in females, urban residents, Christians, older individuals, married, the better educated and the nonpaid. Age and locality were identified as best predictors in males and females, respectively. Key words: Waist-to-height ratio; adult; Bangladeshi DOI: 10.3329/imcj.v4i2.6496Ibrahim Med. Coll. J. 2010; 4(2): 49-58
Phenotypic detection of metallo-β-lactamase among the clinical isolates of imipenem resistant Pseudomonas and Acinetobacter in tertiary care hospitals of Dhaka city
Authors: Anwar Shaheda , Miah Md Ruhul Amin , Saleh Ahmed Abu , Sattar Humayun , Ahmed Sharmeen
Published: November 2010

The rapid spread of Metallo-β-lactamase (MBL) producing Gram negative bacilli represents a matter of great concern worldwide. The study analyzed the occurrence of MBL production in carbapenem resistant Pseudomonas and Acinetobacter isolates over one year period. A total of 132 Pseudomonas and 76 Acinetobacter isolates were obtained from two tertiary care hospitals of Dhaka city. A total of 53 Pseudomonas and 29 Acinetobacter isolates were selected because of their resistance to carbapenem specially imipenem (IPM). Screening for MBL production was performed in these isolates by IPM-EDTA microdilution MIC method. 44 (83%) IPM resistant Pseudomonas and 19 (65.5%) Acinetobacter isolates were MBL producer by IPM-EDTA microdilution MIC method. These results suggest that MBL producing Pseudomonas and Acinetobacter isolates are emerging in our country and it is essential to screen carbapenem resistant isolates for MBL production. DOI: 10.3329/imcj.v4i2.6498Ibrahim Med. Coll. J. 2010; 4(2): 63-65