bluuebunny/crossref_metadata_2025 huggingface dataset:
Nutrition, Glucocorticoids and Pancreas Development
Authors: Bréant B. , Gesina E. , Blondeau B.
Published: April 2006

Low birth weight is strongly predictive of hypertension, cardiovascular diseases, obesity, insulin resistance and diabetes. The mechanisms by which fetal undernutrition and, hence, low birth weight increase the risk of developing these diseases are unclear. To investigate the hypothesis of a primary defect in beta-cell development, we designed a rat model of undernutrition, involving an overall reduction in maternal food intake. In this model, fetuses with intrauterine growth retardation have a decreased beta-cell mass, which persists into adulthood and ultimately causes glucose intolerance, thereby mimicking features of the metabolic syndrome. Maternal undernutrition causes elevations in glucocorticoid concentrations, which, in turn, cause a reduction in beta-cell mass in the fetus. Our data also suggest a key role of glucocorticoids when nutrient supply is normal. By combining in-vitro studies with in-vivo investigations in mice lacking the glucocorticoid receptor in the whole organism or in specific pancreatic cell populations, we have shown that the glucocorticoid receptor is critical for ensuring pancreatic architecture and survival, as well as for beta-cell mass expansion during a critical developmental window. Glucocorticoids act on precursor cells before the onset of hormone gene expression and are likely to programme beta-cell differentiation by modifying the balance of specific transcription factors, mostly Pdx-1. Glucocorticoids should therefore be considered as important hormones in pancreatic development, in situations of both normal nutrition and undernutrition. To investigate whether this is also the case in human pancreatic development, we studied the expression of the glucocorticoid receptor and that of the transcription factor Pdx-1 on pancreatic specimens from very early to late stages of development of the human embryo. In terms of beta-cell ontogeny, expression of the glucocorticoid receptor in the pancreas coincides with that of the transcription factor Pdx-1 in beta cells. These results are consistent with a possible role for glucocorticoids during human pancreatic development.
Puberty after Prenatal Growth Restraint
Authors: Ibáñez L. , de Zegher F.
Published: April 2006

There is increasing evidence for a link between prenatal growth and pubertal development. Here we highlight a selection of pubertal characteristics in children who were born small for gestational age (SGA). Boys born SGA are at risk of high levels of follicle-stimulating hormone (FSH) and low levels of inhibin B and a small testicular volume during adolescence. In girls born SGA, the age at pubertal onset and the age at menarche are advanced by about 5–10 months; prenatal growth restraint may also be associated with higher FSH levels and smaller internal genitalia in adolescence. The ovulation rate was found to be reduced in adolescent girls born SGA, and an insulin-sensitizing therapy was capable of raising this low ovulation rate. Menarche is definitely advanced in girls born SGA with precocious pubarche and in those with an early-normal onset of puberty. Current evidence suggests that insulin resistance is a key mechanism linking a post-SGA state to early menarche; hence, insulin sensitization may become a valid approach to prevent early menarche and early growth arrest in girls born SGA.
Small for Gestational Age and the Metabolic Syndrome: Which Mechanism Is Suggested by Epidemiological and Clinical Studies?
Authors: Lévy-Marchal C. , Czernichow P.
Published: April 2006

The metabolic and cardiovascular complications associated with in-utero undernutrition have been identified during the past 10 years. Reduced fetal growth is independently associated with an increased risk of development of cardiovascular diseases, the insulin-resistance syndrome or one of its components (i.e., hypertension, dyslipidaemia, impaired glucose tolerance and type 2 diabetes). Insulin resistance appears to be a key component underlying these metabolic complications. Although the mechanism remains unclear, several pieces of evidence support an active role of adipose tissue in the emergence of insulin resistance (an abnormal growth pattern and repartition, hypersensitivity to catecholamines, regulation of leptin and adiponectin secretion and modulation of peroxisome proliferator-activated receptor γ). Among individuals born SGA, those who are more at risk of gaining excess adiposity are those who are thin at birth following a period of fetal growth restriction. This period of undernutrition is followed by a neonatal period of catch-up growth and renutrition. This pattern induces important modifications in adipose tissue, with long-term consequences, among which is a high risk of early development of insulin resistance. Not all individuals born SGA will show such modifications in adipose tissue, meaning that not all of those born SGA are at risk of insulin resistance and diabetes. From a broader point of view, several hypotheses have been proposed over the past 10 years to explain this unexpected association between being born SGA and the later development of disease. Each of them points to a detrimental fetal environment, to a genetic susceptibility or to interactions between these two components playing a critical role in this context. Although not confirmed, the hypothesis suggesting that this association could be the consequence of genetic/environmental interactions remains the most attractive.
Metabolic Aspects of Insulin Resistance in Individuals Born Small for Gestational Age
Authors: Vaag A. , Jensen C. Bjørn , Poulsen P. , Brøns C. , Pilgaard K. , Grunnet L. , Vielwerth S. , Alibegovic A.
Published: April 2006

Numerous studies have shown an association between low weight at birth and being born small for gestational age (SGA) on the one hand and risk of developing insulin resistance and type 2 diabetes on the other. Our studies in twins have indicated a non-genetic age-dependent origin of insulin resistance and type 2 diabetes associated with being born SGA. In order to gain insight into the molecular metabolic defects and mechanisms linking SGA with insulin resistance and type 2 diabetes, we performed a series of experiments in young and elderly twins, and, in particular, in young men (aged 19–23 years) with a weight at birth at term in the lowest 10th percentile with no family history of diabetes. The control group included age-matched men with birth weights at term in the upper normal range. While body mass index and waist-to-hip ratios were similar in the individuals born SGA and controls, dual-energy X-ray absorptiometry studies documented a higher degree of abdominal obesity in the men who had a low weight at birth. Using the gold standard hyperinsulinaemic-euglycaemic clamp technique combined with glucose tracers and studies of forearm glucose uptake, we found an impairment of insulin-stimulated glycolytic flux and reduced forearm (muscle) glucose uptake in the face of normal whole-body glucose uptake. In addition, we found a significantly decreased insulin secretion rate during oral glucose ingestion after correction for insulin action (disposition index), a paradoxical enhanced insulin suppression of hepatic glucose production and lower fasting plasma glycerol levels, suggesting impaired lipolysis. Finally, analysis of skeletal muscle biopsies showed reduced muscle expression of several key proteins involved in insulin signalling and glucose transport, including protein kinase C-ζ, the two subunits of phosphoinositol 3-kinase (i.e., p85α and p110β) and the insulin-sensitive glucose transporter, Glut-4, in individuals of low birth weight. In conclusion, being born SGA and of low birth weight is associated with type 2 diabetes in a non-genetic manner, and programming of muscle insulin action and signalling represents an early mechanism responsible for this association.
,,Islam Observed" – ,,Islam Obscured". Lokale Religionsforschung aus translokaler Perspektive
Authors: Bräunlein Peter J.
Published: April 2006

In his famous study ,,Islam Observed," Clifford Geertz poses general critical questions for the study of religion. Taking Geertz's critique and the question ,,what is Islam?" as starting points, this paper explores problems caused by misleading dichotomies such as ,,great" and ,,little" traditions, ,,oral/literal," ,,folk/orthodoxy," etc. Instead of perpetuating the idea of a ,,true Islam," concepts such as ,,discursive tradition," ,,frame of reference," and ,,translocalisation" are employed in order to dissolve the particularuniversal antagonism following several recent (trans-)local studies of Islam.
Wohin mit der Religionswissenschaft? Skizze zur Lage der Religionsforschung und zu Möglichkeiten ihrer Entwicklung
Authors: Krech Volkhard
Published: April 2006

This essay outlines the current situation of religious studies and provides suggestions for possible developments in organization, method, and methodology. The author argues that religious studies can remain distinctive as a discipline, but have an interdisciplinary approach in research and teaching. The contribution concludes with three examples that show the feasibility of integral religious studies.
Estimation of Tropospheric Temperature Trends from MSU Channels 2 and 4
Authors: Spencer Roy W. , Christy John R. , Braswell William D. , Norris William B.
Published: April 2006

The problems inherent in the estimation of global tropospheric temperature trends from a combination of near-nadir Microwave Sounding Unit (MSU) channel-2 and -4 data are described. The authors show that insufficient overlap between those two channels’ weighting functions prevents a physical removal of the stratospheric influence on tropospheric channel 2 from the stratospheric channel 4. Instead, correlations between stratospheric and tropospheric temperature fluctuations based upon ancillary (e.g., radiosonde) information can be used to statistically estimate a correction for the stratospheric influence on MSU 2 from MSU 4. Fu et al. developed such a regression relationship from radiosonde data using the 850–300-hPa layer as the target predictand. There are large errors in the resulting fit of the two MSU channels to the tropospheric target layer, so the correlations from the ancillary data must be relied upon to provide a statistical minimization of the resulting errors. Such relationships depend upon the accuracy of the particular training dataset as well as the dataset time period and its global representativeness (i.e., temporal and spatial stationarity of the statistics). It is concluded that near-nadir MSU channels 2 and 4 cannot be combined to provide a tropospheric temperature measure without substantial uncertainty resulting from a necessary dependence on ancillary information regarding the vertical profile of temperature variations, which are, in general, not well known on a global basis.
The Value of Routine Site Visits in Managing and Maintaining Quality Data from the Oklahoma Mesonet
Authors: Fiebrich Christopher A. , Grimsley David L. , McPherson Renee A. , Kesler Kris A. , Essenberg Gavin R.
Published: April 2006

The Oklahoma Mesonet, jointly operated by the University of Oklahoma and Oklahoma State University, is a network of 116 environmental monitoring stations across Oklahoma. Technicians at the Oklahoma Mesonet perform three seasonal (i.e., spring, summer, and fall) maintenance passes annually. During each 3-month-long pass, a technician visits every Mesonet site. The Mesonet employs four technicians who each maintain the stations in a given quadrant of the state. The purpose of a maintenance pass is to 1) provide proactive vegetation maintenance, 2) perform sensor rotations, 3) clean and inspect sensors, 4) test the performance of sensors in the field, 5) standardize maintenance procedures at each site, 6) document the site characteristics with digital photographs, and 7) inspect the station’s hardware. The Oklahoma Mesonet has learned that routine and standardized station maintenance has two unique benefits: 1) it allows personnel the ability to manage a large network efficiently, and 2) it provides users access to a multitude of station metadata.
Attenuation Calibration of an X-Band Weather Radar Using a Microwave Link
Authors: Rahimi A. R. , Holt A. R. , Upton G. J. G. , Krämer S. , Redder A. , Verworn H-R.
Published: April 2006

The attenuation of a radar signal is a serious problem facing meteorologists and hydrologists. In heavy rain, reflectivity information can be completely lost from large portions of a radar scan. The problem is particularly acute for X-band radars.

Current methods of correcting for attenuation face many difficulties, mainly because the actual amount of attenuation at any given time is unknown. In this paper a backward-iterative attenuation-correction algorithm is presented that uses the attenuation measured by a microwave link with its receiver collocated with an X-band weather radar in Essen, Germany. Data are also available from a network of rain gauges located in the vicinity of the link path. This network provides a measure of “ground truth” rainfall against which radar estimates can be compared.

The results show that the algorithm can recover much of the reflectivity information that is lost due to attenuation of the radar beam. The method is seen to be particularly effective in convective conditions where heavy rainfall can cause severe attenuation.
Correlation Coefficients between Horizontally and Vertically Polarized Returns from Ground Clutter
Authors: Zrnić Dusan S. , Melnikov Valery M. , Ryzhkov Alexander V.
Published: April 2006

Characteristics of the magnitude and phase of correlation coefficients between horizontally and vertically polarized returns from ground clutter echoes are quantified by analyzing histograms obtained with an 11-cm wavelength weather surveillance radar in Norman, Oklahoma. The radar receives simultaneously horizontal and vertical (SHV) electric fields and can transmit either horizontal fields or both vertical and horizontal fields. The differences between correlations obtained in this SHV mode and correlations measured in alternate H, V mode are reviewed; a histogram of differential phase obtained in Florida using alternate H, V mode is also presented. Data indicate that the backscatter differential phase of clutter has a broad histogram that completely overlaps the narrow histogram of precipitation echoes. This is important as it implies that a potent discriminator for separating clutter from meteorological echoes is the texture of the differential phase. Values of the copolar cross-correlation coefficient from clutter overlap completely those from precipitation, and effective discrimination is possible only if averages in range are taken. It is demonstrated that the total differential phase (system and backscatter) depends on the polarimetric measurement technique and the type of scatterers. In special circumstances, such as calibrating or monitoring the radar, clutter signal can be beneficial. Specifically, system differential phase can be estimated from histograms of ground clutter, receiver differential phase can be estimated from precipitation returns, and from these two, the differential phase of transmitted waves is easily computed.
Quantifying the Airflow Distortion over Merchant Ships. Part I: Validation of a CFD Model
Authors: Moat Bengamin I. , Yelland Margaret J. , Pascal Robin W. , Molland Anthony F.
Published: April 2006

The effects of flow distortion created by the ship’s hull and superstructure bias wind speed measurements made from anemometers located on ships. Flow distortion must be taken into account if accurate air–sea flux measurements are to be achieved. Little work has been undertaken to examine the wind speed bias due to flow distortion in wind speed reports from voluntary observing ships (VOS). In this first part of a two-part paper the accuracy of the computational fluid dynamics (CFD) code VECTIS in simulating the airflow over VOS is investigated. Simulations of the airflow over a representation of the bridge of a VOS are compared to in situ wind speed measurements made from six anemometers located above the bridge of the RRS Charles Darwin. The ship’s structure was ideal for reproducing the flow over VOS when the wind is blowing onto either beam. The comparisons showed VECTIS was accurate to within 4% in predicting the wind speed over ships, except in extreme cases such as wake regions or the region close to the bridge top where the flow may be stagnant or reverse direction. The study showed that there was little change in the numerically predicted flow pattern above the bridge with change in Reynolds number between 2 × 105 and 1 × 107. The findings showed that the CFD code VECTIS can reliably be used to determine the mean flow above typical VOS.
d–l Conversion Pathways between Optical Isomers of Alanine: Applications of the Scaled Hypersphere Search Method to Explore Unknown Reaction Routes in a Chiral System
Authors: Ohno Koichi , Maeda Satoshi
Published: April 2006

d–l conversion pathways of α-alanine have been discovered by theoretical search of potential energy surfaces at the level of B3LYP/6-311++G(d,p). No direct conversion channel via only one transition state could be found between d and l optical isomers of alanine. It is demonstrated that there are four types of conversion channels in chiral amino acids. The interconversion of four functional groups (H, CH3, NH2, and COOH) around the asymmetric carbon atom can occur as rotation of a single-bonded pair of two groups involving either NH2 or COOH together with H or CH3.
Photochemistry of the N-Nitrosoaniline Having a Diazo Function in an Ar Matrix at 10 K: EZ-Isomerization, Liberation of Nitric Oxide, and Its Recombination
Authors: Takeda Mitsuhiro , Murata Shigeru
Published: April 2006

On irradiation of p-(N-methyl-N-nitrosoamino)phenyldiazomethane (1) in an Ar matrix at 10 K, the liberation of nitric oxide (NO) to afford the quinoidal radical 2 was directly observed by means of IR spectroscopy. The photoisomerization of (E)-1 to its Z-isomer preceded the NO liberation. Warming the matrix containing NO and 2 caused their disappearance to give an EZ-mixture of the quinoidal imine 3 by the recombination of NO with a radical center of 2. The photoisomerization of (Z)-3 to (E)-3 was also observed.
The Employment of Indium Nanoparticles in Barbier-type Reaction of Allylic Chloride in Water
Authors: Li Jiaming , Zha Zhenggen , Sun Lilin , Zhang Yan , Wang Zhiyong
Published: April 2006

Indium nanoparticles have been employed in the reactions of various carbonyl compounds with allyl (crotyl) chloride in water, affording the corresponding alcohols with high yields. The crotylation gave exclusive γ-adducts with a dominant syn-isomer.
One-dimensional Polynuclear Spin-crossover Iron(III) Complex Axially Bridged by 1,3-Bis(4-pyridyl)propane
Authors: Imatomi Shinya , Kitashima Ryoko , Hamamastu Takefumi , Okeda Miki , Ogawa Yoshihiro , Matsumoto Naohide
Published: April 2006

A one-dimensional (1D) polynuclear spin-crossover FeIII complex, [FeIII(acacen)(bpyp)]n(BPh4)n, showed a gradual and complete SC over a wide temperature range of ca. 250 K between S = 5/2 and S = 1/2, where acacen = N,N′-bis(acetylacetonato)ethylenediamine, bpyp = 1,3-bis(4-pyridyl)propane, and BPh4− = tetraphenylborate. The single-crystal X-ray structures in the HS, LS, and midpoint between the HS and LS states were determined, and demonstrated that the SC may occur through the alternately arrayed HS- and LS-chains.
Temperature-dependent Penetration of Argon Molecules into Ultramicroporous Tunnel of a Fluoroorganic Molecular Crystal with Alteration of Its Unit Cell Size
Authors: Katagiri Toshimasa , Takahashi Satoshi , Kawabata Koji , Hattori Yoshiyuki , Kaneko Katsumi , Uneyama Kenji
Published: April 2006

A molecular crystal of octamethylene (S,S)-bis(2-hydroxy-3,3,3-trifluoropropanoate) with an ultramicroporous tunnel (φ = 2.5–2.8 Å) starts to adsorb argon (φ = 3.6 Å) at 150–140 K with 7% increase of the one direction of the orthorhombic unit cell. The alteration of the unit cell size indicates the penetration of argon into the tunnel and the soft nature of the microporous molecular crystal.
On the Frequency Response of Model Materials in Hydrotechnics
Authors: Chen J , Zhou L
Published: April 2006

The properties of frequency response of five kinds of model materials in hydrotechnics are discussed and analyzed by the static tension test and the dynamic cantilever beam test. The frequency response and the changing of the modal dynamic modulus of elasticity are compared between linear elastic and viscoelastic materials. The results show that the modal dynamic modulus of elasticity for linear elastic material is insensitive to frequency and remains stable, while the modal modulus for viscoelastic material changes obviously with frequency, especially at low frequency, which leads to large simulation errors. In this paper, the line portion of the frequency response curve is suggested to be the working frequency, which can eliminate large simulation errors and result in ideal results.
Entwicklung eines Spannungsimpulsnormals für die Charakterisierung von Höchstfrequenzsystemen (Development of a Voltage Pulse Standard for the Characterization of High-Frequency Components)
Authors: Bieler Mark , Seitz Steffen , Spitzer Meinhard , Hein Günter , Pierz Klaus , Siegner Uwe
Published: April 2006

An der Physikalisch-Technischen Bundesanstalt (PTB) werden seit mehreren Jahren Messmethoden entwickelt, die eine rückführbare Charakterisierung von koplanaren und koaxialen Höchstfrequenzkomponenten ermöglichen. Hierbei werden optoelektronische Verfahren eingesetzt, um in einen Frequenzbereich vorzudringen, der für kommerzielle Netzwerkanalysatoren nicht zugänglich ist. In diesem Artikel wird die Entwicklung eines nationalen, primären Spannungsimpulsnormals für koplanare und koaxiale Wellenleiter aufgezeigt. Das Beispiel der Zeitbereichscharakterisierung eines 70-GHz-Samplingoszilloskops verdeutlicht die Bedeutung eines solchen Primärstandards für die Hochfrequenzmesstechnik.
Magnetorelaxometrie magnetischer Nanoteilchen für die quantitative und spezifische Analyse von Biomolekülen (Magnetorelaxometry of Magnetic Nanoparticles for the Quantitative and Specific Analysis of Biomolecules)
Authors: Ludwig Frank
Published: April 2006

Die Magnetorelaxometrie (MRX) magnetischer Nanoteilchen ist eine sehr aussichtsreiche Methode zur Realisierung von so genannten Magnetorelaxations-Immunoassays (MARIA). Solche Immunoassays haben im Vergleich zu anderen den Vorteil, dass keine Auswaschschritte ungebundener Marker erforderlich sind und die Marker durch magnetische Feldgradienten manipuliert werden können. Wir haben einen Relaxationsmessplatz auf der Grundlage einer differentiellen Fluxgate-Anordnung aufgebaut und verschiedene Magnetit-Ferrofluide auf ihre Eignung für die Realisierung eines MARIA getestet.
Doppler-Global-Velozimetrie mit Laserfrequenzmodulation zur präzisen Messung von Geschwindigkeitsprofilen (Doppler Global Velocimetry with Laser Frequency Modulation for Precise Measurements of Velocity Profiles)
Authors: Fischer Andreas , Büttner Lars , Czarske Jürgen , Müller Harald , Eggert Michael
Published: April 2006

Es wird ein neuartiges Doppler-Global-Velozimetrie(DGV)-Verfahren mit Laserfrequenzmodulation zur berührungslosen flächenhaften Geschwindigkeitsmessung in einer Strömung beschrieben. Die DGV-Technik beruht auf der Auswertung der Intensitätsänderung, die durch eine Laserfrequenzänderung aufgrund des Doppler-Effektes an der Flanke einer molekularen Absorptionskennlinie hervorgerufen wird. Bei dem konventionellen DGV-Verfahren werden zwecks Referenzierung zwei Kameras verwendet. Dadurch können so genannte Bildausrichtungsfehler auftreten, die das Messergebnis wesentlich verfälschen. Bei dem neuen DGV-Verfahren mit Laserfrequenzmodulation wird hingegen nur eine Kamera benötigt, sodass Bildausrichtungsfehler entfallen und eine geringere Messunsicherheit erreicht werden kann. Es wird experimentell gezeigt, dass bei dem neuen Verfahren Streulichtintensitätsschwankungen die Messunsicherheit nicht beeinträchtigen, falls die Modulation der Laserfrequenz hinreichend schnell ist. Die minimal gemessene Messunsicherheit betrug 0.02 m/s.
Effect of 2,4-D and inoculation with Azorhizobium caulinodans on maize
Authors: Saikia S. P. , Saikia S. P. , Jain V. , Jain V. , Srivastava G. C. , Srivastava G. C.
Published: April 2006

Research over the last few years has shown that inoculation with nitrogen-fixing bacteria of the genus
Azorhizobium
presents an alternative for (or supplement to) chemical fertilization, mainly due to the capability of the bacteria to produce plant growth- promoting hormones. The
Azorhizobium caulinodans
strain ORS 571 in combination with 2,4-D was able to colonize the root interior of an Indian maize cultivar. After transplanting to pots, it was noticed that nodulated and
Azorhizobium
-treated plants showed higher chlorophyll content in the leaf and enhanced nitrate reductase activity, leading to higher yield as compared to the control plants (non-nodulated). A plant growth-promoting effect was clearly visible in all inoculated plants examined. nodulated plants treated with
Azorhizobium
had higher physiological activities as compared to plants treated only with
Azorhizobium
.
Azorhizobium
therefore creates potentially better symbiosis in the form of
para
-nodules and promotes a higher level of nitrogen fixation, leading to better growth and plant development, with reduced requirements for chemical fertilizers.
Differential response of two Vicia faba cultivars to drought: Growth, pigments, lipid peroxidation, organic solutes, catalase and peroxidase activity
Authors: El-Tayeb M. A.
Published: April 2006

A study on the germination of five
Vicia faba
cultivars exposed to polyethylene glycol-induced water stress indicated that cv Giza 40 showed the highest germination capacity and cv Giza 667 the lowest. The effect of low soil water content was studied on the plant growth, photosynthetic pigment content, organic solutes, relative water content (RWC), lipid peroxidation, membrane stability index (MSI), and the catalase (CAT) and peroxidase (POX) activity in the leaves of 21-day-old
Vicia faba
cv Giza 40 and cv Giza 667 plants. With respect to dry weight (DW), drought caused a greater decrease in cv Giza 667 than in cv Giza 40, indicating that cv Giza 40 was more tolerant of low soil water content. Drought decreased the Chl a, Chl b and carotenoid contents and the Chl a/b and carotenoid/Chl a+b ratios in the leaves of cv Giza 667, while in cv Giza 40 a significant increase in these pigment parameters was observed under drought stress. Drought caused a decrease in RWC and MSI and an increase in the lipid peroxidation level and in the catalase (CAT) and peroxidase (POX) activity in both the cultivars, but the decline in RWC and MSI and the increase in lipid peroxidation level in response to drought stress were greater in cv Giza 667 than in cv Giza 40. The CAT and POX activities were higher in Giza 40 than in Giza 667 under both control and drought conditions. Drought induced the accumulation of soluble sugars, soluble proteins, free amino acids and proline in both cultivars. However, this accumulation was lower in cv Giza 667 than in the more tolerant cv Giza 40. These results indicate that cv Giza 40 showed better protection against drought-induced oxidative stress through higher CAT and POX activities and osmolyte concentrations than cv Giza 667.
The 1,3-dipolar cycloaddition of 1-methylphthalazinium ylides to non-symmetrically activated alkynes on a solid support under microwave irradiation
Authors: Dima Stefan , Zbangioc Gheorghita , Mangalagiu Ionel
Published: April 2006

In this paper, a comparative study of the reaction of 1-methylphthalazinium ylides with non-symmetrically activated alkynes in a solid medium by classical heating and under microwaves is presented. The reactants were impregnated on a mineral support (Al2O3 - KF) or were brought into catalytic conditions through interphase solid - liquid transfer in the absence of a solvent and were then subjected to microwave irradiation. The reaction of 1-methylphthalazinium ylides with nonsymmetrically activated alkynes on a mineral support and in phase transfer catalysis under microwave irradiation is a regioselective reaction and results in larger yields in a shorter time than under classical conditions.
Direct oxidation of benzene to phenol catalyzed by a vanadium-substituted heteropolymolybdic acid catalyst
Authors: Tang Ying , Zhang Jin
Published: April 2006

The direct synthesis of phenol by hydroxylation of benzene with hydrogen peroxide over a vanadium substituted heteropolymolybdic acid catalyst was investigated at 70 ?C. Hydrogen peroxide was used as the oxidant while 36 wt.% acetic acid was employed as the solvent. After 100 minutes, the selectivity for phenol was 93% and the yield of phenol was 10.1 %. The catalyst was characterized by elemental analysis, thermogravimetry, infrared spectroscopy, UV-Vis spectroscopy, X-ray diffraction, and 31P-NMR and 51V-NMR techniques. The experimental conditions, such as reaction temperature, the amount of hydrogen peroxide and catalyst, were investigated. The as-prepared phenol could be separated by column chromatography and was characterized by infrared and mass spectrometry.
Phytochemical investigation of Anthemis cotula
Authors: Vuckovic Ivan , Vujisic Ljubodrag , Vajs Vlatka , Tesevic Vele , Janackovic Pedja , Milosavljevic Slobodan
Published: April 2006

The investigation of roots of Anthemis cotula (Asteraceae) from east Serbia revealed, in addition to polyacetylenes previously isolated from the same species, three prenylated 4-hydroxyacetophenones, detected for the first time in any Anthemis species. It is possible that they act as phytoalexins in the plant. From the aerial parts, six linear sesquiterpene lactones (four known and two new ones), as well as two known flavones, apigenin and hispidulin, were isolated.
Modifications for the improvement of catalyst materials for hydrogen evolution
Authors: Paunovic Perica , Popovski Orce , Jordanov Hadzi , Dimitrov Aleksandar , Slavkov Dragan
Published: April 2006

The structural and electrocatalytic characteristics of composite materials based on non-precious metals were studied. Precursors of metallic phase (Ni, Co or CoNi) and oxide phase (TiO2) were grafted on a carbon substrate (Vulcan XC-72) by the sol-gel procedure and thermally treated at 250 ?C. Ni and CoNi crystals of 10-20 nm were produced, in contrast the Co and TiO2 were amorphous. The dissimilar electronic character of the components gives rise to a significant electrocatalytic activity for the hydrogen evolution reaction (HER), even in the basic series of prepared materials. Further improvement of the catalysts was achieved by modification of all three components. Hence, Mo was added into the metallic phase, TiO2 was converted into the crystalline form and multiwall carbon nanotubes (MWCNTs) were used instead of carbon particles. The improvement, expressed in terms of the lowering the hydrogen evolution overpotential at 60 mA cm-2, was the most pronounced in the Ni-based systems grafted on MWCNTs (120 mV lower HER overpotential) compared to 60 mV in case of Ni-based systems grafted on crystalline TiO2 (TiO2 prepared at 450 ?C) and of Ni-based systems containing 25 at.% Mo. Nevertheless, even with the realized enhancement, of all the tested materials, the Co-based systems remained superior HER catalysts.
Kinetic spectrophotometric determination of Co(II) ion by the oxidation of ponceau 4R by hydrogen peroxide
Authors: Grahovac Zora , Mitic Snezana , Pecev Emilija , Tosic Snezana
Published: April 2006

Anew, sensitive and simple kinetic method has been developed for the determination of traces of Co(II) ions based on their catalytic effect in the oxidation of trisodium-2-hydroxy-1-(4-sulphonato-1-naphthylazo)naphthalene-6,8-disulphonate (red artificial color Ponceau 4R) by hydrogen peroxide in borate buffer. The reaction was followed spectrophotometrically by tracing the oxidation product at 478.4 nm within 1 min after the initiation of the reaction. The optimum reaction conditions are: borate buffer (pH 10.50), Ponceau 4R (8 x10-6 mol/dm3), H2O2 (3 x10-2 mol/dm3) at 22 ?C. Following this procedure, Co(II) can be determined with a linear calibration graph up to 1.17 ng/cm3 and a detection limit of 0.20, based on the 3??criterion. The relative error ranges between 4.80-3.25 % for the concentration interval of Co(II) ions 1.76-17.61 ng/cm3. The effects of certain foreign ions on the reaction rate were determined for an assessment of the selectivity of the method. The method was applied for the determination of Co(II) in pharmaceutical samples.
Hypogalactosylation of immunoglobulin G (IgG) of gingival fluid and saliva at the patient with periodontal disease
Authors: Stefanovic Gordana , Ciric Dragana , Ilic Vesna , Brajovic Gavrilo , Petrovic Sonja , Milosevic Dragan , Milosevic-Jovcic Nadezda
Published: April 2006

Changed glycosylation of immunoglobulin G (IgG), above all, the expression of thermal galactose, influence to numerous functions of those immunoglobulin and correlate with the inflammatory level in a number of diseases. Aim: This work analyses the distribution of IgG subclasses and the content of thermal galactose in them, in saliva and gingival fluid of the patients with periodontal disease and different gum inflammatory level. Materials and methods: It was used saliva and gingival fluid of 30 adults with clinical picture of periodontal disease and 20 persons with healthy periodontium. The qualification of IgG was done by ?dot-blot? procedure and the, and thermal galactose was determined by lectin immunoblot procedure. Results: The division of IgG subclasses in both fluids was different in the patients with periodontal disease and in control samples. In saliva and gingival fluid of the diseased quantitatively dominated IgG2 subclasses, independently from periodontal status. In IgG of both fluids, thermal galactose was exprimated at the healthy periodontium persons (control) and with the person with initial periodontal disease, while at the person with increased periodontal disease the expression of this saccharide wasn?t registered in neither of fluids. Conclusion: The results showed that there is a shift towards hypogalactosyled IgG glikoforms during the process of gum inflammation at the periodontal disease patients. .
Diabetes, Psychiatric Disorders, and the Metabolic Effects of Antipsychotic Medications
Authors: Llorente Maria D. , Urrutia Victoria
Published: April 2006

IN BRIEF

Psychiatric disorders can be a risk factor for, as well as a complication of, diabetes. Antipsychotic medications, widely used to treat a variety of psychiatric conditions, are also associated with diabetes. This article explores the complex relationship among psychiatric disorders, antipsychotic medications, and risk factors for metabolic syndrome and diabetes.
Lipid Management in Type 2 Diabetes
Authors: Solano Maria P. , Goldberg Ronald B.
Published: April 2006

IN BRIEF

Diabetes is associated with a high risk of cardiovascular disease (CVD). The management of diabetic dyslipidemia, a well-recognized and modifiable risk factor, is a key element in the multifactorial approach to prevent CVD in individuals with type 2 diabetes.
Prevention of Progression in Diabetic Nephropathy
Authors: Hall Phillip M.
Published: April 2006

In Brief

Diabetic nephropathy is the most common cause for end-stage renal disease and for patients entering into chronic dialysis care. It occurs in 25–40% of patients with diabetes. Risk factors include hyperglycemia,hypertension, genetic predisposition, glomerular hyperfiltration, proteinuria,the renal renin-angiotensin system, advanced glycation end-products, and possibly reduced nephron number and lipid disorders. Prevention of diabetic nephropathy is crucial. Tight control of diabetes, blood pressure treatment to systolic pressure of < 130 mmHg, reduction of proteinuria, and treatment with drugs that inhibit the renin-angiotensin system are all associated with prevention of or delay in progression of diabetic kidney injury.
Management of Hypertension in Diabetes
Authors: Stults Barry , Jones Robert E.
Published: April 2006

In Brief

Untreated or poorly controlled hypertension can significantly accelerate the development and progression of both the micro- and macrovascular complications of diabetes. Aggressive blood pressure control improves patient outcomes and reduces health care costs. Unfortunately, nearly two-thirds of people with diabetes do not have blood pressure readings within the target range. Effective antihypertensive regimens maximize nonpharmacological therapies, minimize adverse effects on glucose control, lessen the risk of medication-related side-effects, and provide adequate cardiac and renal protection.
Medical Nutrition Therapy for Hypertension and Albuminuria
Authors: Franz Marion J.
Published: April 2006

In Brief

Modest weight reduction, the Dietary Approaches to Stop Hypertension eating plan, sodium reduction, physical activity, and moderation in alcohol intake are effective in lowering blood pressure and preventing hypertension. However,combining these lifestyle interventions is more effective than single approaches. Potassium supplementation can help control or prevent hypertension. Other lifestyle factors—dietary fiber, calcium, magnesium,fish oil intakes—have been studied but have uncertain efficacy. To delay the progression of nephropathy, the first priority of medical nutrition therapy is to assist in glucose and blood pressure control. In addition,instituting a low-protein diet has been shown to improve renal function in people with diabetes.
Rotational Molding
Authors: Dodge Phillip T. , Mahan Duane , Andrzejewski Steve
Published: April 2006

Rotational molding is a unique process to manufacture hollow plastic parts. Design is limitless, and parts can be produced from toys, kayaks, playground equipments to small to large tanks.
Bioinformatics
Authors: Liu Lei , Abbas Ali
Published: April 2006

The past two decades have witnessed revolutionary changes in biomedical research and biotechnology and an explosive growth of biomedical data. High throughput technologies developed in automated DNA sequencing, functional genomics, proteomics, and metabolomics enable production of such high volume and complex data that the data analysis becomes a big challenge. Consequently, a promising new field, bioinformatics, has emerged and is growing rapidly. Combining biological studies with computer science, mathematics and statistics, bioinformatics develops methods, solutions, and software to discover patterns, generate models, and gain insight knowledge of complex biological systems. This chapter presents an introduction to this exciting new field.
Transcranial Magnetic Stimulation
Authors: Ilmoniemi Risto J.
Published: April 2006

TMS can provide maps of reactivity and connectivity. Magnetic stimulation can be used to influence the brain in order to test scientific hypotheses or to obtain diagnostic information. TMS appears to become also a major therapeutic modality, although much work needs to be done to verify results obtained so far. With many new paradigms to come, the future of TMS as a brain mapping tool seems very bright.
Positron Emission Tomography (PET)
Authors: Kontaxakis George
Published: April 2006

Positron emission tomography (PET) is a powerful, proven diagnostic molecular imaging modality that displays the biological basis of function in the organs and systems of the human body unobtainable through any other means. PET allows the quantitative evaluation of the distribution of several pharmaceuticals in a target area
in vivo
. It is a unique diagnostic imaging technique for measuring the metabolic activity of cells in the human body. PET produces images of the body's basic biochemistry and biological activity in a noninvasive way, combining techniques applied in nuclear medicine with the precise localization achieved by computerized image reconstruction. It is, therefore, a powerful diagnostic test that is having a major impact on the diagnosis and treatment of disease, as well as in patient management.
Vector Quantization
Authors: Enis Cetin A. , Nezih Gerek Omer
Published: April 2006

Vector quantization (VQ) is a critical step in representing signals in digital form for computer processing. It has various uses in signal and image compression and in classification. If the signal samples are quantized separately, the operation is called “scalar quantization.” Consequently, if the samples are grouped to form vectors, their quantization is called “vector quantization.” Changing the quantization dimension from one (for scalar) to multiple (for vectors) has many important mathematical and practical implications. VQ produces indices that represent the vector formed by grouping samples. The output index, which is an integer, has little or no physical relation with the vector it is representing, which is formed by grouping real or complex valued samples. The word “quantization” in VQ comes from the fact that similar vectors are grouped together and represented by the same index. Therefore, many distinct vectors on the multidimensional space are quantized to a single vector that is represented by the index. The number of distinct indices defines the number of quantization levels. Assigning indices to a number of vectors has practical applications in compression and classification. This chapter presents the general layout of the VQ operation, introduces VQ design and optimality conditions, and gives examples about compression and classification applications.
Venous Air Embolism: Detection via Wavelet Transform
Authors: Aydin Nizamettin
Published: April 2006

Venous air embolism (VAE) is a potentially lethal complication of surgical procedures in which the operative site is above the right atrium or gas is forced under pressure into a body cavity. Although it is associated with neurosurgery, VAE is also a potential complication of laparoscopic, pelvic, and orthopedic procedures. Therefore, it is important to detect and treat venous air entrainment. A number of techniques for monitoring VAE exist. Asymptomatic circulating emboli can be detected by Doppler ultrasound, which is a noninvasive method for monitoring emboli. Circulating embolus produces an easily identifiable characteristic sound. Embolic Doppler ultrasound signals are short‐duration transient‐like signals. The fast Fourier transform (FFT) is widely used to process embolic Doppler signals. However, the FFT is not ideally suited to analysis of short‐duration embolic signals because of an inherent trade‐off between temporal and frequency resolution. Alternatively, the wavelet transform is an ideal method for analysis and detection of such signals by optimizing time‐frequency resolution.
Assembly of Wiseana Iridovirus: Viruses for Colloidal Photonic Crystals
Authors: Juhl S. B. , Chan E. P. , Ha Y.‐H. , Maldovan M. , Brunton J. , Ward V. , Dokland T. , Kalmakoff J. , Farmer B. , Thomas E. L. , Vaia R. A.
Published: April 2006

In vitro assembly of Wiseana iridescent virus (WIV) yields iridescent pellets and films with structural color more vivid than in the native insect. WIV is icosahedral in shape, 140 nm in diameter, with 30 nm long fibrils attached to the outer surface, and exhibits a surface charge ca. 1/6th that of a comparable polymer colloid. The low surface charge and tethered chains on the virus surface allow the facile modification of the interparticle distance. Directed sedimentation yields predominantly an amorphous liquid‐like packing of the virus. Such samples exhibit a broad reflection band that is angle independent and for which the broad maximum can be reversibly shifted from blue towards red with increased hydration. Slow sedimentation and flow‐assisted assembly methods produce thin films with a polycrystalline morphology that exhibit narrower, more intense reflectivity peaks, which are hydration and angle dependent. This study points toward the potential of viral particles for photonic crystals where their unique structural features (icosahedral symmetry, extreme monodispersity, precise surface functionalization, and tethered surface chains of low surface‐charge density) may lead to superior control of optical properties of their assembled arrays.
High‐Performance Organic Light‐Emitting Diodes Based on Intramolecular Charge‐Transfer Emission from Donor–Acceptor Molecules: Significance of Electron‐ Donor Strength and Molecular Geometry
Authors: Kulkarni A. P. , Kong X. , Jenekhe S. A.
Published: April 2006

Organic light‐emitting diodes based on intramolecular‐charge‐transfer emission from two related donor–acceptor (D–A) molecules, 3,7‐[bis(4‐phenyl‐2‐quinolyl)]‐10‐methylphenothiazine (BPQ‐MPT) and 3,6‐[bis(4‐phenyl‐2‐quinolyl)]‐9‐methylcarbazole (BPQ‐MCZ), were found to have electroluminescence (EL) efficiencies and device brightnesses that differ by orders of magnitude. High brightness (> 40 000 cd m–2) and high efficiency (21.9 cd A–1, 10.8 lm W–1, 5.78 % external quantum efficiency (EQE) at 1140 cd m–2) green EL was achieved from the BPQ‐MPT emitter, which has its highest occupied molecular orbital (HOMO) level at 5.09 eV and a nonplanar geometry. In contrast, diodes with much lower brightness (2290 cd m–2) and efficiency (1.4 cd A–1, 0.66 lm W–1, 1.7 % EQE at 405 cd m–2) were obtained from the BPQ‐MCZ emitter, which has its HOMO level at 5.75 eV and exhibits a planar geometry. Compared to BPQ‐MCZ, the higher‐lying HOMO level of BPQ‐MPT facilitates more efficient hole injection/transport and a higher charge‐recombination rate, while its nonplanar geometry ensures diode color purity. White EL was observed from BPQ‐MCZ diodes owing to a blue intramolecular charge‐transfer emission and a yellow–orange intermolecular excimer emission, enabled by the planar molecular geometry. These results demonstrate that high‐performance light‐emitting devices can be achieved from intramolecular charge‐transfer emission, while highlighting the critical roles of the electron‐donor strength and the molecular geometry of D–A molecules.