bluuebunny/crossref_metadata_2025 huggingface dataset:
Maternal Lipid Metabolism and Placental Lipid Transfer
Authors: Herrera E. , Amusquivar E. , López-Soldado I. , Ortega H.
Published: April 2006

During early pregnancy, long-chain polyunsaturated fatty acids (LC-PUFA) may accumulate in maternal fat depots and become available for placental transfer during late pregnancy, when the fetal growth rate is maximal and fetal requirements for LC-PUFAs are greatly enhanced. During this late part of gestation, enhanced lipolytic activity in adipose tissue contributes to the development of maternal hyperlipidaemia; there is an increase in plasma triacylglycerol concentrations, with smaller rises in phospholipid and cholesterol concentrations. Besides the increase in plasma very-low-density lipoprotein, there is a proportional enrichment of triacylglycerols in both low-density lipoproteins and high-density lipoproteins. These lipoproteins transport LC-PUFA in the maternal circulation. The presence of lipoprotein receptors in the placenta allows their placental uptake, where they are hydrolysed by lipoprotein lipase, phospholipase A2 and intracellular lipase. The fatty acids that are released can be metabolized and diffuse into the fetal plasma. Although present in smaller proportions, maternal plasma non-esterified fatty acids are also a source of LC-PUFA for the fetus, their placental transfer being facilitated by the presence of a membrane fatty acid-binding protein. There is very little placental transfer of glycerol, whereas the transfer of ketone bodies may become quantitatively important under conditions of maternal hyperketonaemia, such as during fasting, a high-fat diet or diabetes. The demands for cholesterol in the fetus are high, but whereas maternal cholesterol substantially contributes to fetal cholesterol during early pregnancy, fetal cholesterol biosynthesis rather than cholesterol transfer from maternal lipoproteins seems to be the main mechanism for satisfying fetal requirements during late pregnancy.
Size at Birth, Postnatal Growth and Risk of Obesity
Authors: Ong K.K.
Published: April 2006

Epidemiological studies over the last 15 years have shown that size at birth, early postnatal catch-up growth and excess childhood weight gain are associated with an increased risk of adult cardiovascular disease and type 2 diabetes. At the same time, rising rates of obesity and overweight in children, even at pre-school ages, have shifted efforts towards the identification of very early factors that predict risk of subsequent obesity, which may allow early targeted interventions. Overall, higher birth weight is positively associated with subsequent greater body mass index in childhood and later life; however, the relationship is complex. Higher birth weight is associated with greater subsequent lean mass, rather than fat mass. In contrast, lower birth weight is associated with a subsequent higher ratio of fat mass to lean mass, and greater central fat and insulin resistance. This paradoxical effect of lower birth weight is at least partly explained by the observation that infants who have been growth restrained in utero tend to gain weight more rapidly, or ‘catch up’, during the early postnatal period, which leads to increased central fat deposition. There is still debate as to whether there are critical early periods for obesity: does excess weight gain during infancy, childhood or even very early neonatal life have a greater impact on long-term fat deposition and insulin resistance? Early identification of childhood obesity risk will be aided by identification of maternal and fetal genes that regulate fetal nutrition and growth, and postnatal genes that regulate appetite, energy expenditure and the partitioning of energy intake into fat or lean tissue growth.
Early Influences on the Tempo of Puberty
Authors: van Weissenbruch M.M. , Delemarre-van de Waal H.A.
Published: April 2006

Fetal growth retardation appears to be associated with an increased risk of premature adrenarche, early puberty, polycystic ovary syndrome and associated fertility problems. In a rat model of intrauterine growth retardation, based on ligation of the uterine arteries, the onset of puberty was delayed in female pups, with anovulation during the first cycle. The ovaries showed a lower number of follicles. The onset of puberty was also delayed in male pups. Testosterone production was lower in these growth-retarded rats compared with controls. The relationship between birth weight and the onset of puberty and pubertal progression in different cohorts of healthy children has been examined. In girls, no differences were observed in timing and progression of puberty, including age of menarche, between groups of different birth weights. In boys, a relatively delayed onset of puberty was observed in those with low birth weight, with a normally timed progression. In children with low birth weight, particularly boys, higher dehydroepiandrosterone levels were found compared with children with a normal birth weight, indicating an overactive adrenal gland in children with low birth weight. These data indicate that impaired fetal growth may have long-lasting effects on pubertal development. The fact that results of human studies on the relationship between fetal growth and the onset of puberty are often controversial may be explained by the heterogeneity of children born small for gestational age with respect to the intrauterine insult that they experience. From rat studies, it is clear that a serious intrauterine insult associated with growth failure can lead to dysregulation of puberty and gonadal function.
Prematurity and Insulin Sensitivity
Authors: Mericq V.
Published: April 2006

Premature infants of low and extremely low birth weight represent a challenge for neonatal intensive care units and paediatricians. These neonates may be at increased risk of insulin resistance and diabetes perinatally and during childhood. During the first week of postnatal life, infants born prematurely are at risk of abnormalities in glucose homeostasis. Additionally, there are major differences in their glucose/insulin homeostasis compared with infants born at term. Preterm infants are at risk of hypoglycaemia, due to decreases in deposits of glycogen and fat that occur during the third trimester, and also to transient hyperinsulinaemia. Hyperglycaemia may also be observed in preterm infants during the perinatal period. These infants are unable to suppress glucose production within a large range of glucose and insulin concentrations, insulin secretory response is inappropriate, insulin processing is immature and there is an increased ratio of the glucose transporters Glut-1/Glut-2 in fetal tissues, which limits sensitivity and hepatocyte reaction to increments in glucose/insulin concentration during hyperglycaemia. In addition, increased concentrations of tumour necrosis factor α present in intrauterine growth retardation (IUGR) and induce insulin resistance. It has been proposed that the reduced insulin sensitivity may result from adaptation to an adverse in utero environment during a critical period of development. We have investigated postnatal insulin resistance in 60 children born with very low birth weight and either small for gestational age or at an appropriate size for gestational age. This study showed that IUGR, rather than low birth weight itself, was associated with increased fasting insulin levels. As poor fetal growth may be associated with the development of obesity, type 2 diabetes and the metabolic syndrome in later life, it is important that we continue to increase our understanding of the effects of IUGR on postnatal growth and metabolism.
Growth Hormone Therapy in Short Children Born Small for Gestational Age
Authors: de Zegher F. , Ong K.K. , Ibáñez L. , Dunger D.B.
Published: April 2006

There is still a lack of data from randomized, controlled, long-term studies of growth hormone (GH) treatment in children born small for gestational age (SGA), but the available evidence indicates consistently that GH therapy is a valid growth-promoting treatment in these children, particularly if started early. Whilst side effects appear uncommon, ongoing surveillance is required and treated children should be monitored for changes in glucose homeostasis, lipid profiles and blood pressure, especially during puberty. We provide an update on the safety and efficacy of GH treatment in short children born SGA.
A Bioequivalence Study of Two Oral Desmopressin Tablet Formulations
Authors: Kaehler Stefan T. , Steiner Ilka M. , Sauermann Robert , Scheidl Helmut , Mueller Markus , Joukhadar Christian
Published: April 2006

The present study was carried out to test bioequivalence between two different oral desmopressin formulations. Sixty healthy volunteers were enrolled in the study and were randomly assigned to receive the test (T) and reference (R) drug in a two-period two-sequence, crossover, analyst-blinded study design. Subjects received an oral dose of 400 µg of desmopressin acetate separated by a wash-out period of at least 7 days. The area under the concentration-time curve (AUC) over 12 h in plasma and the maximum concentration (Cmax) were compared by analysis of variance (ANOVA) after log transformation. The mean ratios of the T to R drug were within the bioequivalence boundaries with mean values of 1.00 (90% CI: 0.87–1.14) and 1.03 (90% CI: 0.92–1.15) for AUC0–t and AUC0–inf, respectively. For the Cmax, the mean ratio of the T to R drug was 0.97 (90% CI: 0.87–1.08). The rate and the extent of oral desmopressin absorption were identical for both formulations. Hence, the desmopressin test tablet met all bioequivalence criteria of the marketed reference desmopressin tablet.
Posttraumatic Syndromes in Children and Adolescents after Road Traffic Accidents – A Prospective Cohort Study
Authors: Schäfer Ingo , Barkmann Claus , Riedesser Peter , Schulte-Markwort Michael
Published: April 2006

Background: The impact of road traffic accidents (RTAs) on the physical health of children is well recognized, but their psychological consequences have only recently become a topic of research. While other traumatic experiences in childhood are well studied, this kind of trauma has been poorly investigated to date. Sampling and Methods: A prospective cohort study was conducted of 8- to 18-year-old children and adolescents who were involved in RTAs in a large urban area during a 6-month period. The children and adolescents were interviewed within 1 week after the accident and, again, 3 months later. In total, 72 children and adolescents took part in the study. Symptoms of posttraumatic stress, depression and anxiety were assessed by a structured clinical interview and standardized questionnaires. Results: One week after the accident, 11% of the children met the diagnostic criteria for posttraumatic stress disorder (PTSD) according to ICD-10 and a further 13% met the criteria for ‘subsyndromal PTSD’. Complex syndromes consisting of subsyndromal posttraumatic stress, (separation) anxiety and depression were common among those children. Isolated cases of anxiety and depression symptoms were also observed but rarely reached an impairing level. Three months after the accident, 25% of the children reported persistence of the PTSD symptoms (measured by the Impact of Event Scale – Revised). The strongest predictor of the extent of posttraumatic stress after 3 months was proven to be the initial level of PTSD symptoms. This predictor alone accounted for 38% of its variance. Conclusions: Our results provide evidence that even after ‘everyday’ RTAs, psychological consequences are common. Special attention should be paid to the common occurrence of subsyndromal psychological disturbances and more complex syndromes. The results further indicate the limitations of the PTSD concept in the assessment of posttraumatic disturbances in childhood and adolescence.
Gewalt und Religion. Eine religionswissenschaftliche Untersuchung zu den anthropologischen Ursachen und kulturellen Überformungen der Gewaltanwendung unter Menschen
Authors: Bumbacher Stephan Peter
Published: April 2006

Intra-species killing occurs in all known human societies as well as among chimpanzees as wars between different groups. This parallel may be the product of a common evolution as both species are the closest biological relatives. Unlike apes, however, human beings not only compete for territories but also for power in general, goods, etc. As the product of mankind's further evolution, religions legitimate this inter-group violence.
A Simple Method for the Assessment of the Cloud Cover State in High-Latitude Regions by a Ground-Based Digital Camera
Authors: Souza-Echer M. P. , Pereira E. B. , Bins L. S. , Andrade M. A. R.
Published: April 2006

This work describes the development of a simple method of field estimating the sky cloud coverage percentage for several applications at the Brazilian Antarctic Station, Ferraz (62°05′S, 58°23.5′W). The database of this method was acquired by a digital color camera in the visible range of the spectrum. A new algorithm was developed to classify each pixel according to a criteria decision process. The information on the pixel contamination by clouds was obtained from the saturation component of the intensity, hue, and saturation space (IHS). For simplicity, the images were acquired with a limited field of view of 36° pointing to the camera’s zenith to prevent direct sunlight from reaching the internal charge-coupled device (CCD) on the camera. For a priori–classified clear-sky images, the accuracy of the method was superior to 94%. For overcast-sky conditions, the corresponding accuracy was larger than 99%.

A comparison test was performed with two human observers and our method. The results for the 29 images collected for several time of days during 50 days in 1999 summer were compared to visual observations of these same digital images by two trained field meteorologists. Correlation coefficients between human observers and the automatic method ranged from 0.84 for clear-sky conditions, and the lowest was 0.09 for undefined-sky conditions.
Toward Estimating Climatic Trends in SST. Part I: Methods of Measurement
Authors: Kent Elizabeth C. , Taylor Peter K.
Published: April 2006

To assess climatic changes in sea surface temperature (SST), changes in the measurement method with time and the effect of these changes on the mean SST must be quantified. Observations from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) have been analyzed for the period from 1970 to 1997 using both SST measurement metadata contained within the dataset and a World Meteorological Organization (WMO) catalog of observing ships. The WMO metadata were particularly important in identifying engine-intake SSTs during the 1970s, but increased method identification over the entire period. There are strong regional variations in the preferred SST measurement method, with engine-intake SST most common in the Pacific and bucket SST preferred by countries bordering the Atlantic. The number of engine-intake SSTs increases over time and becomes more numerous than buckets by the early 1980s.

There are significant differences between SST observations made by different methods. The rounding of reports is more common for engine-intake SST than for either bucket or hull sensor SST, which degrades its quality. Significant time-varying biases exist between SST derived from buckets and from engine intakes. The SST difference has a strong seasonal signal with bucket SST being relatively cold in winter, probably resulting from heat loss from the buckets, and warm in summer, probably resulting from solar warming or the sampling of a shallow warm layer. There is also a long-term trend with engine-intake SST being relatively warm in the early period but with a small annual mean difference between the two methods by 1990.
Toward Estimating Climatic Trends in SST. Part II: Random Errors
Authors: Kent Elizabeth C. , Challenor Peter G.
Published: April 2006

Random observational errors for sea surface temperature (SST) are estimated using merchant ship reports from the International Comprehensive Ocean–Atmosphere Data Set (ICOADS) for the period of 1970–97. A statistical technique, semivariogram analysis, is used to isolate the variance resulting from the observational error from that resulting from the spatial variability in a dataset of the differences of paired SST reports. The method is largely successful, although there is some evidence that in high-variability regions the separation of random and spatial error is not complete, which may have led to an overestimate of the random observational error in these regions. The error estimates are robust to changes in the details of the regression method used to estimate the spatial variability.

The resulting error estimates are shown to vary with region, time, the quality control applied, the method of measurement, the recruiting country, and the source of the data. SST data measured using buckets typically contain smaller random errors than those measured using an engine-intake thermometer. Errors are larger in the 1970s, probably because of problems with data transmission in the early days of the Global Telecommunications System. The best estimate of the global average random error in ICOADS ship SST for the period of 1970–97 is 1.2°C if the estimates are weighted by ocean area and 1.3°C if the estimates are weighted by the number of observations.
Toward Estimating Climatic Trends in SST. Part III: Systematic Biases
Authors: Kent Elizabeth C. , Kaplan Alexey
Published: April 2006

A method is developed to quantify systematic errors in two types of sea surface temperature (SST) observations: bucket and engine-intake measurements. A simple linear model is proposed where the SST measured using a bucket is cooled or warmed by a fraction of the air–sea temperature difference and the SST measured using an engine intake has a constant bias. The model is applied to collocated nighttime observations made at moderate wind speeds, allowing the effects of solar radiation and strong vertical gradients in the upper ocean to be neglected. The analysis is complicated by large random errors in all of the variables used. To estimate coefficients in this model, a novel type of linear regression, where errors in two variables are correlated with each other, is introduced. Because of the uncertainty in a priori estimates of the error covariance matrix, a Bayesian analysis of the regression problem is developed, and maximum likelihood approximations to the posterior distributions of the model parameters are obtained.

Results show that the temperature change in bucket SST resulting from the air–sea temperature difference can be detected. The analysis suggests that bucket SST may be in error by a fraction from 0.12° ± 0.02° to 0.16° ± 0.02°C of the air–sea temperature difference. When this temperature change of the bucket SST is accounted for, a warm bias in engine-intake SST in the mid- to late 1970s and the 1980s was found to be smaller than that suggested by previous studies, ranging between 0.09° ± 0.06° and 0.18° ± 0.05°C. For the early 1990s the model suggests that the engine-intake SSTs may have a cold bias of −0.13° ± 0.07°C.
Row-Action Inversion of the Barrick–Weber Equations
Authors: Green J. J. , Wyatt L. R.
Published: April 2006

The Barrick–Weber equations describe the interaction of radar signals with the dynamic ocean surface, and so provide a mathematical basis for oceanic remote sensing. This report considers the inversion of these equations with several of the row-action methods commonly used to solve large linear systems with unstructured sparsity. It is found that the performance of the methods in inverting both synthetic and measured Doppler spectral data is comparable, with the method of Chahine–Twomey–Wyatt offering a slight advantage in the reliability of the recovery of the full directional wave spectrum and of parameters derived from its integration. Some remarks and open questions on the ill-posedness of the inversion problem conclude the paper.
Effective Radius of Ice Cloud Particle Populations Derived from Aircraft Probes
Authors: Heymsfield Andrew J. , Schmitt Carl , Bansemer Aaron , van Zadelhoff Gerd-Jan , McGill Matthew J. , Twohy Cynthia , Baumgardner Darrel
Published: April 2006

The effective radius (re) is a crucial variable in representing the radiative properties of cloud layers in general circulation models. This parameter is proportional to the condensed water content (CWC) divided by the extinction (σ). For ice cloud layers, parameterizations for re have been developed from aircraft in situ measurements 1) indirectly, using data obtained from particle spectrometer probes and assumptions or observations about particle shape and mass to get the ice water content (IWC) and area to get σ, and recently 2) from probes that derive IWC and σ more directly, referred to as the direct approach, even though the extinction is not measured directly.

This study compares [IWC/σ] derived from the two methods using datasets acquired from comparable instruments on two aircraft, one sampling clouds at midlevels and the other at upper levels during the Cirrus Regional Study of Tropical Anvils and Cirrus Layers (CRYSTAL) Florida Area Cirrus Experiment (FACE) field program in Florida in 2002. A penetration by one of the aircraft into a cold midlatitude orographic wave cloud composed of small particles is further evaluated. The σ and IWC derived by each method are compared and evaluated in different ways for each aircraft dataset. Direct measurements of σ exceed those derived indirectly by a factor of 2–2.5. The IWC probes, relying on ice sublimation, appear to measure accurately except when the IWC is high or the particles too large to sublimate completely during the short transit time through the probe. The IWC estimated from the particle probes are accurate when direct measurements are available to provide constraints and give useful information in high IWC/large particle situations.

Because of the discrepancy in σ estimates between the direct and indirect approaches, there is a factor of 2–3 difference in [IWC/σ] between them. Although there are significant uncertainties involved in its use, comparisons with several independent data sources suggest that the indirect method is the more accurate of the two approaches. However, experiments are needed to resolve the source of the discrepancy in σ.
Quantifying the Airflow Distortion over Merchant Ships. Part II: Application of the Model Results
Authors: Moat Bengamin I. , Yelland Margaret J. , Molland Anthony F.
Published: April 2006

Wind speed measurements obtained from ship-mounted anemometers are biased by the presence of the ship, which distorts the airflow to the anemometer. Previous studies have simulated the flow over detailed models of individual research ships in order to quantify the effect of flow distortion at well-exposed anemometers, usually sited on a mast in the ship's bows. In contrast, little work has been undertaken to examine the effects of flow distortion at anemometers sited on other merchant ships participating in the voluntary observing ship (VOS) project. Anemometers are usually sited on a mast above the bridge of VOS where the effects of flow distortion may be severe. The several thousand VOS vary a great deal in shape and size and it would be impractical to study each individual ship.

This study examines the airflow above the bridge of a typical, or generic, tanker/bulk carrier/general cargo ship using computational fluid dynamics models. The results show that the airflow separates at the upwind leading edge of the bridge and a region of severely decelerated flow exists close to the bridge top with a region of accelerated flow above. Large velocity gradients occur between the two regions.

The wind speed bias is highly dependent upon the anemometer location and varies from accelerations of 10% or more to decelerations of 100%. The wind speed bias at particular locations also varies with the relative wind direction, that is, the angle of the ship to the wind. Wind speed biases for various anemometer positions are given for bow-on and beam-on flows.
In Situ Atmospheric Turbulence Measurement Using the Terrestrial Magnetic Field—A Compass for a Radiosonde
Authors: Harrison R. Giles , Hogan Robin J.
Published: April 2006

A method for in situ detection of atmospheric turbulence has been developed using an inexpensive sensor carried within a conventional meteorological radiosonde. The sensor—a Hall effect magnetometer—was used to monitor the terrestrial magnetic field. Rapid time scale (10 s or less) fluctuations in the magnetic field measurement were related to the motion of the radiosonde, which was strongly influenced by atmospheric turbulence. Comparison with cloud radar measurements showed turbulence in regions where rapid time-scale magnetic fluctuations occurred. Reliable measurements were obtained between the surface and the stratosphere.
Calibrating the Spatial Response of Bio-Optical Sensors
Authors: Wolk Fabian , Yamazaki Hidekatsu , Li Hua , Lueck Rolf G.
Published: April 2006

This article describes an experimental method used to establish the spatial wavenumber response of in situ fluorometers. The method is applied to a fluorometer developed to measure the structure of the fluorescence field at high spatial wavenumbers. This fluorometer detects fluorescence variations on centimeter scales by creating a sampling volume in the undisturbed flow region, outside of the sensor housing. The sampling volume is created by intersecting beams of blue excitation light. To establish the size of the sampling volume and the amount of spatial averaging, the fluorometer and a fast response thermistor are towed repeatedly through a warm, fluorescent plume in a tow tank. The ratio of the measured fluorescence and temperature spectrum determines the wavenumber response of the fluorometer. The measured spectral ratio is well described by the transfer function of a first-order, low-pass filter with a half-power point at 22 cpm. The equivalent spatial resolution is 7 mm. The transfer function model can be used to correct measured fluorescence spectra for the limited wavenumber response of the sensor.
Highly Selective Reduction of Cinnamaldehyde to Cinnamyl Alcohol Using Nanometric Alkali Metal Hydrides
Authors: Fan Yinheng , Wu Qiang , Jin Dan , Zou Yunling , Liao Shijian , Xu Jie
Published: April 2006

Under mild reaction conditions, cinnamaldehyde was reduced to cinnamyl alcohol with high selectivity and conversion using nano-LiH or nano-NaH as a reducing agent. Selectivity of 99.8% was obtained as reduced by nano-LiH with conversion of 99.4% in short reaction times.
Strikingly Extended Morphology of Cells Grown on Carbon Nanotubes
Authors: Aoki Naofumi , Yokoyama Atsuro , Nodasaka Yoshinobu , Akasaka Tsukasa , Uo Motohiro , Sato Yoshinori , Tohji Kazuyuki , Watari Fumio
Published: April 2006

The morphology of cells cultured on carbon nanotube (CNTs) scaffolds was investigated using a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM) and it was shown that the cells extended strikingly in all directions and numerous filopodia extended far from the cells.
Synthesis of Conducting Mesoporous Materials Implanting Carbon Nanotubes inside Particles
Authors: Lee Hyung Ik , Youm Chul , Pak Chanho , Kim Sung Soo , Chang Hyuk , Seoung Doyoung , Kim Jae-Ho , Kwon Young-Uk , Kim Ji Man
Published: April 2006

Carbon nanotubes have been successfully implanted inside mesoporous particles as conducting nanowires by one-step synthetic strategy, giving dramatically reduced sheet resistances.
Water Conditioner Adjuvant and Fertilizer Formulation Effect on Micronutrient-Glyphosate Tank Mixtures
Authors: Bernards ML , Penner D , Michael J
Published: April 2006

Tank-mixing foliar micronutrient fertilizers with glyphosate may reduce weed control because of antagonistic cations present in the spray solution. This research was conducted (1) to quantify the antagonism caused by various formulations of copper (Cu), iron (Fe), manganese (Mn), and zinc (Zn), and (2) to determine the extent that water conditioner adjuvants may prevent the antagonism from occurring. Most formulations of copper, iron, manganese, and zinc antagonized glyphosate efficacy on giant foxtail and velvetleaf. Formulations containing EDTA, HEDTA, or flavonol were the least antagonistic; those containing the sulfate salt or a lignosulfonic acid chelate were the most antagonistic. Tank mixtures including the adjuvant NT2 overcame the antagonism more often than those containing ammonium sulfate (AMS) or CANG3. Two micronutrient blends, one with (MC) and one without (MS) the chelates citric acid and EDTA, both reduced glyphosate efficacy on giant foxtail and velvetleaf. The addition of AMS or NT to these blends increased velvetleaf control, but neither adjuvant overcame the antagonism.
Qualität für Messergebnisse – Messunsicherheit nach GUM (Quality for Measurement Results – Measurement Uncertainty According to GUM)
Authors: Weckenmann Albert , Sommer Klaus-Dieter , Siebert Bernd R. L.
Published: April 2006

Der wichtigste und am häufigsten verwendete Parameter zur Beschreibung der Qualität eines Messergebnisses ist die Messunsicherheit. Um die Vergleichbarkeit von Werten der Messunsicherheit zu gewährleisten, wird diese seit 1993 bestimmt entsprechend dem Guide to the expression of Uncertainty in Measurement, kurz GUM [1], welcher international vereinbarte und anerkannte grundlegende Zusammenhänge zur Messunsicherheitsermittlung beinhaltet. Die Grundlagen und die Teilschritte der GUM-konformen Berechnung der Messunsicherheit werden dargelegt.
Influence of volunteer durum wheat ( Triticum durum ) cultivars and density on lentils ( Lens culinaris )
Authors: Ghosheh H. Z. , Ghosheh H. Z. , El-Shatnawi M. K. , El-Shatnawi M. K.
Published: April 2006

Greenhouse experiments were conducted for two consecutive seasons to investigate the influence of volunteer durum wheat cultivars and density on lentil growth and yield. It is speculated that interference may be severe whenever wheat and lentils are rotated in semi-arid regions. Lentil:durum wheat ratios of 1:0, 1:1, 1:2, 1:4 and 1:6 were evaluated utilizing two durum wheat cultivars, Hourani and ACSAD 65. The results indicated that wheat interference did not influence lentil growth for the first 80 days after crop emergence, but afterwards, the lentil height, straw and seed yield were affected by the presence of wheat. A 50% reduction in either lentil straw or seed yield was estimated from the interference of a single plant per pot. The semi-tall cultivar Hourani had more adverse effects on lentil growth and yield than the semi-dwarf cultivar ACSAD 65.
A comparison of cytoplasmic and chemically-induced male sterility systems for hybrid performance in wheat ( Triticum aestivum L.)
Authors: Adugna A. , Adugna A. , Nanda G. S. , Nanda G. S. , Bains N. S. , Bains N. S.
Published: April 2006

Cytoplasmic (
Triticum timopheevii
-based) and chemically induced (CH9832- based) male sterility systems were compared for hybrid performance in wheat. A total of 40 genotypes including 10 CMS-based hybrids, 10 CHA-based hybrids, 10 B lines and 10 R lines were included in the experiment. analysis of variance revealed significant differences between the genotypes for all the characters studied. Differences between the hybrids and their parents were significant for all the characters. There were also significant differences between the hybrids resulting from the two systems of sterility. This study of 10 comparable hybrids showed, on average, midparent heterosis of 30.2 and 7.3% for CMS- and CHA-derived hybrids, respectively. Generally, the CMS-based hybrids were superior to their CHA-based equivalents for grain yield performance. In spite of the incomplete fertility the higher grain yield in CMS-based hybrids was attributed to the profuse tillering and high thousand-grain weight. On the other hand, the CHA-based hybrids had lower yield performance due to the lower thousand-grain weight and tillering. The lower grain weight and tillering in these hybrids compared with their CMS-based equivalents might be due to the toxic effect of the CHA, which was carried over to the hybrid and affected vigour. As a whole the CMS system was found to be better than the CHA system (based on the particular CHA used in this study) for hybrid performance in wheat.
Diterpenoids and phenolics from Pseudopanax simplex
Authors: Zidorn Christian , Horak Silja , Weavers Rex , Ellmerer Ernst , Stuppner Hermann , Klink Van
Published: April 2006

An ethanolic extract of Pseudopanax simplex yielded kaempferol-3,7-di-O-rhamnopyranoside, chlorogenic acid, maltol glucoside, ent-kaur-16-en-18-oic acid, and 4R,5S,9R,10S,13S-ent-pimara-7,15-dien-19-oic acid. Full NMRdata for the last compound are reported for the first time.
A study of the inhibiton of copper corrosion by triethyl phosphate and triphenyl phosphate self-assembled monolayers
Authors: Guo Wenjuan , Chen Shenhao , Houyi M.A.
Published: April 2006

Two kinds of phosphates, triethyl phosphate (TEP) and triphenyl phosphate (TPP), were used to form self-assembled monolayers for the inhibition of the corrosion of copper in 0.2 mol dm-3 NaCl solution. Electrochemical impedance spectroscopy (EIS) was applied to investigate the inhibition effects. The results showed that their inhibition ability first increased with increasing immersion time in ethanolic solutions of the corresponding compounds. However, when the immersion time was increased over some critical point, the inhibition effect decreased. For the same immersion time, the inhibition effect of the TPP monolayer was more pronounced than that of the TEP monolayer. Thus, ab initio calculations were used to interpret the relationship between the inhibition effects and the structures of the compounds.
Electrochemical characterization of the passive films formed on niobium surfaces in H2SO4 solutions
Authors: Arsova Irena , Prusi Abdurauf , Grcev Toma , Arsov Ljubomir
Published: April 2006

The electrochemical formation and characteristics of passive films on niobium surfaces in aqueous H2SO4 solutions were studied using open circuit potential and cyclic voltammetry. In the potential region between -1.0 and 1.2 V(NHE), the cyclic voltammetry data showed that the active/passive transition involves slow metal dissolution followed by the formation of semiconducting passive oxide films. The possible electrochemical reactions and the change of the oxidation steps of some niobium oxides occurring in the passive film during the polarization are proposed. A strong influence of the natural air-formed oxide film on the chemical composition of the passive film was shown. This influence makes chemical structure of thin passive films more complicated than that of thick anodic films. It is shown that the passive films consists of more or less stable oxides, such as NbO, NbO2 and Nb2O5. The Raman spectra revealed that the thin passive films were amorphous, while the films formed at higher voltages consist, primarily, of well-crystallized Nb2O5.
Chemical vapour deposition of diamond using low pressure flat combustion flame
Authors: Vilotijevic Miroljub , Grahovac Nebojsa , Milovanovic Ljiljana , Marinkovic Slobodan
Published: April 2006

Diamond coatings were deposited onto Mo and WC-Co substrates using a low pressure premixed acetylene-oxygen flat flame by means of a special apparatus operating at 50 mbar. Uniform diamond coatings containing significant amounts of non-diamond carbon were deposited over areas of ?7 cm2 onto Mo substrates, the coating thickness after 1 h deposition amounted to ?1 ?m. Upon machining an Al-12 % Si alloy under identical conditions, the diamond coated WC-Co cutting tool inserts showed 30 % less wear than the as-received inserts.
Computer aided design and manufacturing of dental restorations - “computerized impression” technology
Authors: Todorovic Aleksandar , Lazic Vojkan
Published: April 2006

CAD/CAM technology (Computer Aided Design / Computer Aided Manufacturing) in the matter of fact helps in design and development of two-dimensional or three-dimensional models and their realization on numerical controlled machines. The key to direct or indirect CAD/CAM dental restorations is the measurement of dental preparation in the mouth or on the plaster die. The aim of this paper is to describe the possibilities and the way of function of different computer aided inspection (CAI) systems as a first part of CAD/CAM systems. Different researchers have presented several approaches of methods for three dimensional (3D) measurement. Today, for chairside dental treatment, only the optical method of measurement has lead to satisfactory results in practice. Laboratory CAD/CAM systems use mechanical and optical technologies for 3D measurement. Optical impression grows as a leader of CAI segment of almost every new CAD/CAM system. The most important properties of 3D scanners are: accuracy, volume and speed of measurement and ergonomy of instrument. .
Blood Glucose Awareness Training: What Is It, Where Is It, and Where Is It Going?
Authors: Cox Daniel J. , Gonder-Frederick Linda , Ritterband Lee , Patel Kushal , Schächinger Hartmut , Fehm-Wolfsdorf Gabriele , Hermanns Norbert , Snoek Frank , Zrebiec John , Polonsky William , Schlundt David , Kovatchev Boris , Clarke William
Published: April 2006

Management of type 1 diabetes requires a continual balancing of insulin,fuel intake, and metabolic demand (e.g., exercise). This can only be accomplished with knowledge of where one's blood glucose is and where it is going and knowledge of how to manipulate insulin, fuel, and exercise to manage it. Blood Glucose Awareness Training (BGAT) is a psychoeducational intervention that in part addresses these needs. Fifteen research studies from the United States and Europe, involving single-site and multicenter projects,are reviewed. BGAT has been consistently demonstrated to improve the ability to detect and diminish both hypoglycemia and hyperglycemia while reducing the sequelae of extreme blood glucose levels (e.g., episodes of severe hypoglycemia and driving mishaps). BGAT has recently been transformed for internet delivery, making it available both for clinicians to use with their patients and for individuals with type 1 diabetes to pursue as a self-directed tutorial.
Phosphorus‐Containing Polymers and Oligomers
Authors: Weil Edward D.
Published: April 2006

Phosphorus polymers and oligomers are surveyed with emphasis on methods of synthesis and utility. Red phosphorus is a useful flame‐retardant insoluble polymer. Polyphosphoric acid has catalytic utility, and its salts find use in chelation and flame retardancy. Phosphorus‐nitrogen polymers and oligomers may be involved in the synergistic flame‐retardant action of combinations of phosphorus and nitrogen compounds, such as on cellulose. Lower‐oxidation‐state organic phosphorus polymers and oligomers such as phosphines and phosphites have stabilizer and catalyst utility. Higher‐oxidation‐state phosphorus polymers and oligomers such as phosphates and phosphonates, made mainly by condensation reactions, have flame‐retardant utility in plastics as additives and reactive modifiers, and also in as textile additives and finishes.
Biomedical Electronics
Authors: Min Mart , Parve Toomas , Salo Rodney
Published: April 2006

The unique requirements of biomedical electronics develop from its electrical interface with living tissue, which may involve cutaneous electrodes for an external instrument or wearable device or subcutaneous electrodes in implantable devices as well as other sensors and electrical or mechanical actuators. The overarching requirement for safety and reliability demands designs that include electrical isolation, fault tolerance, and tightly controlled outputs. Additional requirements include small size and low weight without reduced longevity. These needs are normally addressed by using the latest low‐power technology with high‐power density batteries. Integration of electronic devices into medical systems requires fast, reliable, low‐power communication between medical devices and a base station or between multiple implanted or wearable medical devices. Strategies to meet these requirements with low‐voltage CMOS integrated circuit techniques and micropower circuit and system design are developed in this chapter.
Autologous Platelet‐Based Therapies
Authors: Arm Douglas
Published: April 2006

Healing and fusion in challenging bone grafting procedures is not guaranteed using the gold standard of autogenous iliac crest bone, and clinicians are increasingly interested in tissue engineering solutions using cells and signaling factors to enhance both overall success rate and time to fusion. The potential role in wound repair from application of cytokines contained in platelets was initially described more than 20 years ago. A rapid, simple preparation method to perioperatively separate and collect the platelet‐rich fraction was developed a decade later, expanding the potential range of clinical applications. Numerous additional point‐of‐care techniques have since been introduced, potentially providing a cost‐effective alternative to single recombinant proteins. As with many emerging technologies, clinicians are confronted with a frequently conflicting array of largely anecdotal claims for clinical utility. With a focus on structural bone graft repair, this chapter will present the therapeutic basis for clinical use of topically applied autogenous growth factor preparations and summarize existing experimental and application‐specific clinical outcomes reports.
Cognitive Systems
Authors: Viirre Erik
Published: April 2006

Cognitive systems may be described as technology in support of cognitive abilities or as tools for thinking. The entire range of such technologies is large and crosses a wide variety of disciplines. In this article, an outline for bioengineering contributions to cognitive systems will be provided. In the discipline of engineering, several areas are dedicated to development of tools for cognition, such as human–computer interaction, ergonomics, and many components of computer science. Beyond engineering, many disciplines are dedicated to the study and improvement of thinking, from education and psychology to neuroscience and cognitive science. Bioengineering contributions to cognitive systems combine the engineering approach to human–computer interaction with the biophysical information from neuroscience and cognitive science. In this article, the functional aspects of cognitive science will be reviewed: basic physiology of the nervous system, sensory inputs, motor control, and the cognitive functions: attention, memory, language and speech, emotion, consciousness, and higher cognitive functions. How we might interact at a bioengineering level with cognitive processes involves working with the brain as an organ and detecting its action: through behavior and direct recording methods. Finally, bioengineers should keep applications of cognitive science in mind as technologies are developed to interact with the brain.
Pressure Sensors
Authors: Mootanah Rajshree , Bader Dan L.
Published: April 2006

Pressure sensors in biomedical applications are very important because they provide data that may be used to assess physiological function, diagnose disease, and provide for appropriate treatment regimens. Pressure sensors have a large number of applications in biomedicine, in particular, for the measurement of interface pressures and internal pressures. The interface pressures can be measured using conductive polymer pressure sensors, semiconductor strain gauges, metal strain gauges, capacitive pressure sensors, and optoelectronic pressure sensors. Internal pressures can be measured, using the needle manometer method, the Wick catheter method, integrated circuit implantable sensors, and fiber‐optic catheters. The packaging materials of internal pressure sensors are manufactured from biocompatible covering materials to avoid tissue infection and change in sensor characteristics over time. The first section of the chapter outlines the general forms of pressure measurement systems and their characteristics, including performance, accuracy, loading effects, noise, and reliability, which is followed by a detailed summary of instruments and measurement systems in biomedical applications for specific types of pressure measurements. The final section presents the theory behind the components used to form the measurement systems, in particular, the pressure‐sensing elements, transduction.
Pulse Oximetry
Authors: Mendelson Yitzhak
Published: April 2006

Noninvasive monitoring of arterial oxygen saturation by pulse oximetry (SpO
2
) was first adopted by anesthesiologists in the early 1980s in an effort to optimize patient safety. The goal of this technology was to identify as early as possible unrecognized episodes of hypoxemia (insufficient blood oxygenation) that often resulted in irreversible tissue damage and costly malpractice insurance claims. During the past decade, pulse oximetry has become a rapidly growing practice in many fields of clinical medicine, including subacute and long‐term care. Whether used as a safety guard or as a diagnostic tool, this new modality is widely acknowledged to be one of the most important technological advances in patient monitoring. The most important advantage of pulse oximetry is the capability to provide continuous, safe, and cost‐effective monitoring of blood oxygenation noninvasively at the patient bedside. It is particularly useful when a patient is unstable and subject to rapid or unpredictable oxygen desaturation. Pulse oximeters are easy to use, require no user calibration, and provide virtually maintenance‐free operation.
Vascular Networks
Authors: Kannan Ruben Y. , Seifalian Alexander M.
Published: April 2006

The holy grail of artificial tissue is currently limited by the absence of a viable vascular network to sustain it. Although a growing amount of interest exists in engineering such a construct, they are essentially in their infancy. In this chapter, the basic concepts of microcirculation are laid down, along with current state‐of‐the‐art technology used to develop an artificial capillary bed. A major limitation is the poor patency rates, especially at low‐flow states, of contemporary microvascular grafts. Newer options for microvessels including the use of nano‐engineered materials are explored and tissue engineering biological microvessels are also discussed. At the lower end of the spectrum, biomedical researchers have also used angiogenic factors to stimulate capillary development. More recently, stem cell technology has also come into vogue with the potential to promote arteriogenesis. In the future, it is foreseen that all these factors would be synergized to bridge the “missing link” between the arterial system and tissue‐engineered scaffolds.
Vascular Growth and Remodeling
Authors: Humphrey J.D.
Published: April 2006

The goal of this brief review is to highlight the basic structure and function of large blood vessels, to discuss the homeostatic mechanical environment, and to compare five examples of mechanically induced vascular growth and remodeling. By growth, we mean an increase in mass that is achieved locally via an increase in the number or size of cells and/or via a synthesis of extracellular matrix that exceeds removal. Atrophy, then, can be thought of as negative growth. By remodeling, we mean a change in structure that is achieved by reorganizing existing constituents or by synthesizing new constituents that have a different organization. If we track local turnover of material, as we should, growth and remodeling are seen to typically occur hand in hand, and thus should be considered together. It is hoped that this review stimulates the reader's interest in vascular mechanics and mechanobiology, a field of study with great promise to contribute to improving health care delivery.