bluuebunny/crossref_metadata_2025 huggingface dataset:
Why Learn Physics?
Authors: Riendeau Diane
Published: September 2009

In my experience, when students can see an application for knowledge, they are more willing to spend the necessary time to attain it. Certainly your students were motivated at the beginning of the semester. Perhaps now is a good time to get their attention again? One way to motivate our students to learn physics is to show them examples of the way people try to exploit the ignorance of others. Along this vein, I offer these four video clips.

Special thanks to Karl Mamola and the pholks at Physics Northwest for your video suggestions.
Make Your Own Inexpensive Genecons by Hacking Emergency Hand-Cranked LED Flashlights
Authors: MacIsaac Dan
Published: September 2009

On a Faraday generator-related note, many folk use the commercially available Genecon hand-cranked dc generator (a small dc motor in a plastic gearing package usually purchased for about $50 from scientific supply houses—see http://www.arborsci.com/detail.aspx?ID=543 and http://store.pasco.com/pascostore/showdetl.cfm?&Product_ID=1706 for example. A much less expensive version can be hacked from a $10 hand-cranked LED light by simply opening the handset, removing the LEDs and replacing them with alligator jumpers. The hand-cranked flashlights are less durable, but can be widely found on sale—Google “sale hand-cranked flashlight.” A website demonstrating this hacked flashlight is visible at http://tinyurl.com/l32467 with other hacks at https://sites.google.com/a/flosscience.com/flosscience/Home/clever-hacks. Genecon use is thoroughly described in the teacher's manual of the highly regarded and recommended CASTLE physics curriculum freely downloadable from PASCO at http://www.pasco.com/featured-products/castle/page_3.cfm.
Effect of living close to a main road on asthma, allergy, lung function and chronic obstructive pulmonary disease
Authors: Pujades-Rodríguez M , Lewis S , Mckeever T , Britton J , Venn A
Published: September 2009

Background:

A number of epidemiological studies suggest that the risk of asthma is increased among those living in close proximity to major roads. However, the evidence is inconsistent, and effects on asthma and related respiratory and allergic conditions using objective measures such as lung function and allergic sensitisation have not been widely investigated.

Methods:

In 1995, 1996 and 2001 data on respiratory and allergic disease, along with demographic and lifestyle factors, were collected in 59 285 children (aged 2–16 years) and adults as part of the Health Survey for England, a nationally representative annual survey. Using Geographical Information System software, we mapped the location of each participant’s home and computed distance to the nearest major road. We estimated the effect of distance on self-reported wheezing in the past year, asthma, eczema and hay fever in 50 994 participants, and on 1-second forced expiratory volume (FEV1), immunoglobulin E and spirometry-defined chronic obstructive pulmonary disease (COPD) in subgroups of those aged 7+, 11+ and 16+ years, respectively.

Results:

Living within 150 m from a major road was not significantly associated with an increased risk of any of the outcome variables in any age group (adjusted odds ratios ranged from 0.85 to 1.05). Furthermore there was little evidence that risk increased with increasing proximity across the 0–150 m range where contrasts in traffic-related pollutant concentrations are greatest.

Conclusion:

Our analysis of a large and nationally representative population sample did not provide evidence of an adverse effect of living in close proximity to main roads on the risk of asthma, COPD or allergic disease in England.
Paleomagnetism of the Michael Gabbro and Possible Evidence of the Rotation of Makkovik Subprovince
Authors: Fahrig W. F. , Larochelle A.
Published: September 2009

The Michael gabbro forms a belt of thick, predominantly southerly-dipping sheets which extends 200 km inland from the south-central coast of Labrador. The intrusions lie largely within the Makkovik subprovince, have a radioisotopic age of 1500 m.y., and are reversely magnetized with a paleomagnetic pole position of 163 °E, 10 °N. The paleomagnetic results indicate that most of the rocks internal to this belt have not been deformed since the intrusions acquired a stable remanent magnetization, presumably at the time of cooling 1500 m.y. ago. However, the Michael pole position differs significantly from those of rocks of similar age elsewhere in North America. This suggests rotation of the block containing the Michael intrusions relative to these other rocks. The Aillik dikes which also lie within the Makkovik sub-province have a radioisotopic age of about 1100 m.y. and a pole position consistent with that of rocks of similar age elsewhere in the Canadian Shield. The postulated Michael rotation must then have taken place between 1500 and 1100 m.y. ago.The rock at two of the most southerly sites sampled for paleomagnetic study proved to be magnetically unstable and the rock at a third such site, though stably magnetized has a magnetization significantly different from the main body of Michael gabbro intrusions. These three sites may indicate a post-consolidation thermal and tectonic event and their position may help define the Grenville Front in this region.
Exsolution Products in Heated Chalcopyrite
Authors: MacLean Wallace H. , Cabri Louis J. , Gill James E.
Published: September 2009

Chalcopyrite, chalcopyrite-rich ore, talnakhite concentrates, and synthetic Cu–Fe–S compositions were heated, in separate experiments, and quenched. Those heated above 550 °C produced well-formed lenticular lamellae of chalcopyrite arranged in three directions at right angles to one another and set in a darker matrix with distinctly different optical and X-ray properties and different composition. The composition and structure of the matrix depends upon the bulk composition of the starting materials.When heated, chalcopyrite exsolves 10 to 15% pyrite; the remaining phase on quenching yields a grid of near-stoichiometric chalcopyrite in a matrix of talnakhite of variable composition. The presence of pyrite in the starting material does not change the result. Heated mixtures of chalcopyrite, pyrrhotite, and pyrite yield a similar grid of chalcopyrite in a matrix of high-temperature cubanite solid solution.These exsolutions form on quenching, probably at the cubic/tetragonal inversion and are not equilibrium assemblages. Twinning was not observed in samples cooled through the inversion temperature, and, therefore, the fine twin lamellae sometimes observed in natural chalcopyrite may not necessarily have been formed at the cubic/tetragonal inversion.
Hairpins and Superintervals
Authors: Irving E. , Park J. K.
Published: September 2009

The path of apparent polar wandering relative to North America has several sharp turning points or hairpins. These hairpins record rapid changes in the direction of motion of North America relative to the pole. The youngest of these hairpins (in the Cretaceous) corresponds approximately in time to a major "tectonic reorganization" suggested by Coney on other grounds. The older hairpins are also supposed to represent first-order tectonic breaks, and they are therefore used to divide post-Archean time into 5 superintervals. The diastrophic significance of these superintervals is briefly discussed.
Estimating Coho Salmon (Oncorhynchus kisutch) Spawning Escapements by Conducting Visual Surveys in Areas Selected Using Stratified Random and Stratified Index Sampling Designs
Authors: Irvine J. R. , Bocking R. C. , English K. K. , Labelle M.
Published: September 2009

Spawning escapement estimates were obtained for adult and jack (precocious male) coho salmon (Oncorhynchus kisutch) by conducting visual surveys on foot in stream reaches selected by stratified random and stratified index sampling designs. The approach was evaluated for three years in two streams with widely varying escapements; estimates of adult escapements using the stratified index design were always similar to estimates obtained through an independent mark–recapture program. The stratified random design underestimated escapement in every case but one. Because the distribution offish was aggregated, with random sampling there was a higher probability of sampling low fish abundance areas than high-abundance areas. Numbers of jack coho were underestimated with each sampling design, probably because we overestimated our efficiency of seeing these fish. When using this approach, the efficiency of observing fish during surveys and the length of time salmon are alive in the survey area should be estimated; the latter for our survey areas ranged between 13 and 17 d with one exception (8 d). Labour costs associated with estimating escapements to our streams by visual survey indexing techniques were less than by mark–recapture or by operating fish counting fences.
QUANTIZATION OF THE HALL CONDUCTANCE AND DELOCALIZATION IN ERGODIC LANDAU HAMILTONIANS
Authors: GERMINET FRANÇOIS , KLEIN ABEL , SCHENKER JEFFREY H.
Published: September 2009

We prove quantization of the Hall conductance for continuous ergodic Landau Hamiltonians under a condition on the decay of the Fermi projections. This condition and continuity of the integrated density of states are shown to imply continuity of the Hall conductance. In addition, we prove the existence of delocalization near each Landau level for these two-dimensional Hamiltonians. More precisely, we prove that for some ergodic Landau Hamiltonians, there exists an energy E near each Landau level where a "localization length" diverges. For the Anderson–Landau Hamiltonian, we also obtain a transition between dynamical localization and dynamical delocalization in the Landau bands, with a minimal rate of transport, even in cases when the spectral gaps are closed.
2D ISING MODEL WITH COMPETING INTERACTIONS AND ITS APPLICATION TO CLUSTERS AND ARRAYS OF π-RINGS, GRAPHENE AND ADIABATIC QUANTUM COMPUTING
Authors: O'HARE ANTHONY , KUSMARTSEV F. V. , KUGEL K. I.
Published: September 2009

We study the two-dimensional Ising model with competing nearest-neighbour and diagonal interactions and investigate the phase diagram of this model. We show that the ground state at low temperatures is ordered either as stripes or as the Néel antiferromagnet. However, we also demonstrate that the energy of defects and dislocations in the lattice is close to the ground state of the system. Therefore, many locally stable (or metastable) states associated with local energy minima separated by energy barriers may appear forming a glass-like state.

We discuss the results in connection with two physically different systems. First, we deal with planar clusters of loops including a Josephson π-junction (a π-rings). Each π-ring carries a persistent current and behaves as a classical orbital moment. The type of particular state associated with the orientation of orbital moments in the cluster depends on the interaction between these orbital moments and can be easily controlled, i.e. by a bias current or by other means. Second, we apply the model to the analysis of the structure of the newly discovered two-dimensional form of carbon, graphene. Carbon atoms in graphene form a planar honeycomb lattice. Actually, the graphene plane is not ideal but corrugated. The displacement of carbon atoms up and down from the plane can be also described in terms of Ising spins, the interaction of which determines the complicated shape of the corrugated graphene plane.

The obtained results may be verified in experiments and are also applicable to adiabatic quantum computing where the states are switched adiabatically with the slow change of coupling constant.
ASTROID CURVES FOR A SYNTHETIC ANTIFERROMAGNETIC STACK IN AN APPLIED MAGNETIC FIELD
Authors: FORRESTER D. M. , KOVACS E. , KÜRTEN K. E. , KUSMARTSEV F. V.
Published: September 2009

The interaction of two magnetic particles separated by an interlayer is illustrated through the "astroid" curves that represent regions in the magnetic field plane where different numbers of minima associated with stable or metastable states may exist. For a single particle, we describe the astroid curves of the Stoner-Wohlfarth model. The case of two particles is then examined and found to be much more complicated. The energy landscape of the two-particle system contains ferromagnetic, antiferromagnetic and canting states that emerge in response to the level of applied magnetic field. Because of this, up to four energy minima can exist in the system, depending upon the strength of the magnetic field and the material properties of the particles.
ENTANGLEMENT PROPERTIES OF QUANTUM MANY-BODY WAVE FUNCTIONS
Authors: CLARK J. W. , MANDILARA A. , RISTIG M. L. , KÜRTEN K. E.
Published: September 2009

The entanglement properties of correlated wave functions commonly employed in theories of strongly correlated many-body systems are studied. The variational treatment of the transverse Ising model within correlated-basis theory is reviewed, and existing calculations of the one- and two-body reduced density matrices are used to evaluate or estimate established measures of bipartite entanglement, including the Von Neumann entropy, the concurrence, and localizable entanglement, for square, cubic, and hypercubic lattice systems. The results discussed in relation to the findings of previous studies that explore the relationship of entanglement behaviors to quantum critical phenomena and quantum phase transitions. It is emphasized that Jastrow-correlated wave functions and their extensions contain multipartite entanglement to all orders.
SIMILARITIES BETWEEN EMBOLIC STROKE AND PERCOLATION PROBLEMS
Authors: HAGUE J. P. , CHUNG E. M. L.
Published: September 2009

We discuss a recently developed embolic stroke model in relation to models of percolation. When descibing embolic stroke, it is important to know if blood flow can travel from the major arteries to the arterioles supplying the brain. In this sense, the onset of stroke bears some similarity to the central question of percolation theory. The order parameter for the percolation transition is found, and the percolation threshold is investigated. We discuss possible extensions to the model.
SUPERCONDUCTING NANOWIRES: QUANTUM-CONFINEMENT EFFECT ON THE CRITICAL MAGNETIC FIELD AND SUPERCURRENT
Authors: CROITORU M. D. , SHANENKO A. A. , PEETERS F. M.
Published: September 2009

We study the effect of electron confinement on the superconducting-to-normal phase transition driven by a magnetic field and/or on the current-carrying state of the superconducting condensate in nanowires. Our investigation is based on a self-consistent numerical solution of the Bogoliubov-de Gennes equations. We show that in a parallel magnetic field and/or in the presence of supercurrent the transition from superconducting to normal phase occurs as a cascade of discontinuous jumps in the superconducting order parameter for diameters D < 10 ÷ 15 nm at T = 0. The critical magnetic field exhibits quantum-size oscillations with pronounced resonant enhancements.
GENERATION OF VORTICES IN SUPERCONDUCTING DISKS
Authors: WU W. M. , SOBNACK M. B. , KUSMARTSEV F. V.
Published: September 2009

We study the nucleation of vortices in a thin mesoscopic superconducting disk and stable configurations of vortices as a function of the disk size, the applied magnetic field H and finite temperature T. We also investigate the stability of different vortex states inside the disk. Further, we compare the predictions from Ginzburg-Landau (GL) theory and London theory - the GL equations take the superconducting density into account, but the London equations do not. Our simulations from both theories show similar vortex states. As more vortices are generated, more superconducting regions will be destoryed. The GL Equations consider this effect and provide a more accurate estimate.
FLUX CLONING ANOMALITIES IN JOSEPHSON NANO-JUNCTIONS
Authors: HASSAN HANAA FARHAN , KUSMARTSEV FEO V.
Published: September 2009

The propagation of single flux quanta in T -shaped Josephson junctions gives rise to the flux cloning phenomenon. We have studied numerically the dynamics of flux cloning in cases of extended Josephson junctions. The changing thicknesses of T -junctions lead to new and interesting effects in terms of their dynamics. We have found out that when an additional Josephson transmission line is larger than the main Josephson transmission line, numerical simulations do not show the cloning phenomenon and soliton is reflected when it approaches the T junction. This strange result may be happened because the soliton losses more energy in the sharp edge. Although the vortex is moving very highly and it has huge energy but it still does not give birth to a new vortex. We have investigated conditions at which flux cloning occurs when both widths, W and W0, are changing.
ELECTROSTATIC FIELD IN SUPERCONDUCTORS II: BALANCE OF FORCES
Authors: LIPAVSKÝ PAVEL , KOLÁČEK JAN
Published: September 2009

The London theory of diamagnetic currents is discussed from the magnetohydrodynamical point of view. It is argued that the motion of superconducting electrons is controlled by the electrostatic field which balances the Lorentz and the inertial forces.
ON THE COLLISION LOCAL TIME OF BIFRACTIONAL BROWNIAN MOTIONS
Authors: YAN LITAN , LIU JUNFENG , CHEN CHAO
Published: September 2009

Let [Formula: see text], i = 1,2 be two independent bifractional Brownian motions of dimension 1, with indices Hi ∈ (0, 1) and Ki ∈ (0, 1]. We investigate the collision local time of bifractional Brownian motions [Formula: see text] where δ denotes the Dirac delta function at zero. We show that ℓT exists in L2, and it is Hölder continuous of order 1 - min {H1K1,H2K2}, and furthermore, it is also smooth in the sense of Meyer–Watanabe.
Recent Advances in Micro-Particle Image Velocimetry
Authors: Wereley Steven T. , Meinhart Carl D.
Published: September 2009

Microfluidic devices are becoming increasingly common and are seen in applications ranging from biology to nanotechnology and manufacturing. Flow behavior in these small domains can often be counterintuitive because of the low Reynolds number or the relative importance of surface forces. Micro-particle image velocimetry (μPIV) is a quantitative method that can be used to characterize the performance of such microfluidic systems with spatial resolutions better than one micron. Illustrating the impact of this measurement technique, more than 100 journal articles are published per year that feature μPIV velocity measurements. This article discusses the fundamentals of the technique, its theoretical background, and several applications.
Mycorrhizal Symbioses and Plant Invasions
Authors: Pringle Anne , Bever James D. , Gardes Monique , Parrent Jeri L. , Rillig Matthias C. , Klironomos John N.
Published: September 2009

The factors that influence a plant's ability to invade are not well understood. Many mechanisms are involved and the relative importance of different mechanisms depends on the specific invasion. Here we consider one factor—mycorrhizal symbioses. These symbioses are ubiquitous interactions involving the plants and soil fungi of most terrestrial ecosystems. We develop a conceptual framework for considering mycorrhizal symbioses in plant species invasions. The most critical aspects of this framework are: (a) the mycorrhizal status and (b) the growth response of the invading plant, (c) the ability of the plant to associate with different fungi, (d) the quality of the plant as a host for local fungi and feedback dynamics, (e) the biogeography and dispersal of the fungi, (f) the introduction and spread of the fungi, and (g) the ecological consequences of the creation of novel mycorrhizas. These aspects can critically influence the trajectory of a plant invasion, and this symbiosis deserves more attention in plant invasion biology.
Rates of Evolution
Authors: Gingerich Philip D.
Published: September 2009

Darwin thought evolution is slow. Evolution is slow on long time scales, but the fundamental process works on a generation-to-generation scale, not long time scales. Phenotypic variation is geometric normal, with normality reflecting its underlying polygenic source; ln transformation is part of the measurement process. The natural rate unit is the haldane, particularly H0, representing change in standard deviations per generation on a timescale of one generation. When appropriately sampled, rates calculated on longer scales can be projected to a generational timescale. Empirical studies are reviewed concerning: (a) rates of polygenic mutation, (b) rates of response to human versus natural disturbance; and (c) rates of change in a classic study of punctuated equilibrium. Rate studies commonly find phenotypic change on the order of H0 = 0.1 to 0.3 standard deviations per generation. This is fast by any standard. Darwin was wrong on rates, but more right than we knew on natural selection.
VLDL-TG kinetics: a dual isotope study for quantifying VLDL-TG pool size, production rates, and fractional oxidation in humans
Authors: Sørensen Lars P. , Gormsen Lars C. , Nielsen Søren
Published: September 2009

Very-low-density lipoproteins (VLDLs) are large, complex particles containing both surface proteins (e.g., ApoB100) and core lipids, e.g., cholesterol and triglycerides (TG). Whereas ApoB100 kinetics have been thoroughly studied, accurate measurement of VLDL-TG kinetics have proven difficult due to either complex mathematics or laborious procedures. The present study was therefore designed to measure VLDL-TG kinetics by dual isotope ex vivo labeled VLDL-TG tracers and well-established kinetics equations (bolus injection or the primed continuous infusion). Ten healthy Caucasian men [age, 23 ± 3 yr old (mean ± SD); body mass index, 24.7 ± 1.3 kg/m2] were included in the study. VLDL-TG rate of appearance (Ra) was measured using a dual-tracer technique ([9,10-3H]-labeled VLDL-TG and [1-14C]-labeled VLDL-TG) to allow comparison of various bolus decay curve fits with the Ra obtained by the primed continuous infusion (PCI; considered the gold standard). In addition, VLDL-TG fatty acid oxidation was measured as14CO2in exhaled breath, using the hyamine trapping technique. Following a bolus injection, tracer decay was better described by a biexponential than a monoexponential fit ( r2= 0.99 ± 0.01 vs. 0.97 ± 0.04, respectively, P = 0.01). VLDL-TG Ra calculated using the PCI correlated significantly with the biexponential fit (ρ = 0.62, P < 0.05), whereas this was not the case for the monoexponential fit (ρ = −0.18, P = not significant). VLDL-TG Ra using the best fit of the bolus injection method (biexponential) was less than values obtained by the constant infusion technique [biexponential, 34.3 (range, 27.1–69.6) vs. PCI, 44.4 (range, 33.0–72.7), P < 0.05]. Fractional oxidation of VLDL-TG was 37.2 ± 8.8% at 240 min corresponding to 198.8 ± 55.9 kcal/day or 10.6 ± 3.3% of resting energy expenditure (REE). Our data demonstrate that VLDL-TG Ra measured by a biexponential fit to a bolus decay curve correlates well with VLDL-TG Ra measured by a primed continuous infusion, and therefore that a “second” peripheral VLDL-TG compartment with rapid exchange of TG exists. VLDL-TG volume of distribution is therefore greater than previously anticipated. Finally our data supports that VLDL-TG contributes quantitatively to REE.
Cerebral Representation of the Relief of Itch by Scratching
Authors: Vierow Verena , Fukuoka Miyuki , Ikoma Akihiko , Dörfler Arnd , Handwerker Hermann Otto , Forster Clemens
Published: September 2009

Cerebral processing of itch-scratching cycles was studied with functional magnetic resonance imaging (fMRI) in healthy volunteers. The back of the hand was repetitively scratched in the absence and presence of itch induced by histamine applied close to the scratched site. Blood-oxygenation-level-dependent (BOLD) effects were assessed in predefined cortical and subcortical brain regions of interest. Scratch-related activation clusters were found in cortical and subcortical areas which had been associated before with pain processing, namely S1, S2, parietal association cortex, motor and premotor cortex, anterior and posterior insula, anterior and medial cingulum, lateral and medial frontal areas, ipsilateral cerebellum and contralateral putamen. Cortical activations were generally stronger in the contralateral hemisphere. General linear model (GLM) analysis and GLM contrast analysis revealed stronger activations during itch-related trials in the motor and premotor cortex, in lateral frontal fields of both sides, and in a left medial frontal cluster. Subcortically, stronger activation during itch-related scratching trials was found in the contralateral putamen and in the ipsilateral cerebellum. Time course analysis showed significantly higher BOLD levels during the last 3–6 s before the start of scratching when the itch intensity was strongest. This effect was found in frontal areas, in the putamen, and in the somatosensory projection areas. During the scratching, no significant differences were found between itch and control conditions with the exception of the putamen, which showed stronger activations during itch-related scratch bouts. We interpret these itch-related activations anticipating the scratching as possible cerebral correlates of the itch processing and the craving for scratch.
Blockade of a Chemokine, CCL2, Reduces Chronic Colitis-Associated Carcinogenesis in Mice
Authors: Popivanova Boryana Konstantinova , Kostadinova Feodora Ivanova , Furuichi Kengo , Shamekh Mohamed M. , Kondo Toshikazu , Wada Takashi , Egashira Kensuke , Mukaida Naofumi
Published: September 2009

Accumulating evidence indicates the crucial contribution of chronic inflammation to various types of carcinogenesis, including colon carcinoma associated with ulcerative colitis and asbestosis-induced malignant mesothelioma. Ulcerative colitis–associated colon carcinogenesis can be recapitulated in mice by azoxymethane administration followed by repetitive dextran sulfate sodium ingestion. In the course of this carcinogenesis process, the expression of a macrophage-tropic chemokine, CCL2, was enhanced together with intracolonic massive infiltration of macrophages, which were a major source of cyclooxygenase (COX)-2, a crucial mediator of colon carcinogenesis. Mice deficient in CCL2-specific receptor, CCR2, exhibited less macrophage infiltration and lower tumor numbers with attenuated COX-2 expression. Moreover, CCL2 antagonists decreased intracolonic macrophage infiltration and COX-2 expression, attenuated neovascularization, and eventually reduced the numbers and size of colon tumors, even when given after multiple colon tumors have developed. These observations identify CCL2 as a crucial mediator of the initiation and progression of chronic colitis–associated colon carcinogenesis and suggest that targeting CCL2 may be useful in treating colon cancers, particularly those associated with chronic inflammation. [Cancer Res 2009;69(19):7884–92]
Polyunsaturated Fatty Acids and Cardiovascular Disease: Implications for Nutrigenetics
Authors: Allayee Hooman , Roth Nitzan , Hodis Howard N.
Published: September 2009

Cardiovascular disease (CVD) arises as a result of genetic predisposition in the context of a disease-promoting environment. While several risk factors have been identified for CVD, such as elevated serum lipid levels and hypertension, most of the genes identified thus far do not appear to involve such ‘conventional’ risk factors. Moreover, the interactions between genes and environment, such as a diet high in certain fats, adds another level of complexity to CVD and renders identification of the underlying genetic factors even more difficult. Polyunsaturated fatty acids (PUFAs), such as the ω–6 and ω–3 fatty acids, which have multiple roles in membrane structure, lipid metabolism, blood clotting, blood pressure, and, in particular, inflammation, have been linked to the reduction in CVD. Linoleic (ω–6) and α-linolenic acid (ω–3) are essential fatty acids that can be converted into long-chain PUFAs, such as arachidonic acid (AA) and eicosapentaenoic acid (EPA)/docosahexaenoic acid (DHA), respectively. These long-chain PUFAs are metabolized by enzymatically catalyzed systems via cyclooxygenases and lipoxygenases. The 5-lipoxygenase (5-LO)/leukotriene (LT) biosynthesis pathway has been biochemically and genetically associated with CVD traits in mice and humans, particularly in the context of dietary AA and EPA/DHA. In this review, we summarize the biochemical metabolism of ω–3 and ω–6 PUFAs, evaluate the evidence for genetic and nutrigenetic contributions of 5-LO pathway genes to CVD, and discuss the potential of future studies that could identify other gene-dietary interactions between PUFAs and CVD traits.
Transient Ischemic Attacks and Inhibitory Seizures in Elderly Patients
Authors: De Reuck J. , Van Maele G.
Published: September 2009

Background: The new definition of a transient ischemic attack (TIA) makes it more difficult to distinguish it from an inhibitory seizure (IS). Purpose: The present study compares the characteristics of patients with an IS to those with a TIA, taking into account the old and the new definition of a TIA. Patients and Methods: The clinical characteristics and the electroencephalogram (EEG) findings of 25 patients with an IS were compared to 252 patients with a TIA according to the old definition. Subgroups of 10 patients with an IS without structural lesions and 195 TIA patients according to the new definition were also analyzed. The differential diagnostic clues were examined. Results: Differences in age, gender distribution and vascular risk factors were observed only when comparing the overall patient groups. However, these differences disappeared when the subgroups were analyzed. Temporary speech disturbance, associated with some partial amnesia for the event, was the most common clinical presentation of an IS. Additionally, specific and nonspecific postictal EEG abnormalities were observed in the majority of the IS patients, while the EEG was normal in more than 90% of the TIA patients. Conclusions: An IS must be suspected in a patient with a short temporary speech disturbance and partial amnesia for the event. In view of the new definition of a TIA, urgent EEG becomes mandatory in each patient with a brief episode of neurological dysfunction.
The Influence of Diets Deficient in Energy, or in Protein, on Conceptus Weight, and the Placental Transfer of a Non-Metabolisable Amino Acid in the Guinea Pig
Authors: Young Maureen , Widdowson Elsie M.
Published: September 2009

The effect on the guinea pig conceptus of feeding the mother diets deficient in energy or in protein has been investigated. Fetal uptake of a labelled non-metabolisable amino acid, amino-isobutyric acid, injected into the maternal blood stream, was studied at the end of gestation. Both diets retarded fetal growth, influencing litter number and fetal and placental weights. The relationship between fetal and placental weight was similar in the control and restricted-calorie animals, and the transfer studies showed that placental function and fetal uptake per unit weight was similar in the two. Feeding a low-protein diet caused the ratio between fetal and placental weight to increase; enhanced placental transfer and fetal uptake also suggested the possibility of adaptation when the calorie supply is adequate.
Turnover Rates of Fructose and Their Influence on Glucose Blood Level in Preterm and Term Newborns Appropriate for Gestational Age in Comparison with Preterm and Term Small-for-Gestational-Age Infants
Authors: Rautenbach M. , Beyreiss K.
Published: September 2009

Utilization, and total clearance of fructose were determined by methods of blood level kinetics in 40 preterm and term newborns appropriate and small for gestational age. In all groups the total clearance increases from 16.5 to 23.5 ml·kg––1·min––1 at the age of 12–72 h to 27.3–35.5 ml·kg––1·min––1 at the age of 10–12 days. Less than 10% of the fructose infused intravenously are eliminated in the urine.
Balance of Net Base in the Rat. II. Reference Values in Relation to Growth Rate
Authors: Wamberg S. , Kildeberg P. , Engel K.
Published: September 2009

An investigation of mineral and net base balances in weanling, adolescent, food-restricted, and adult Wistar rats is presented. Supplementary studies included whole carcass analysis and measurements on isolated organs and skeleton preparations. The results show that the growing rat is in a state of positive net base balance due to dietary net base being deposited, along with calcium, magnesium, and phosphate, in the skeleton. Rates of gastrointestinal absorption of net base, calcium, magnesium, and phosphorus appeared closely interdependent and rates of retention were subject to extrarenal control. The sum of balances of magnesium and calcium was tightly correlated to the rate of weight gain. The results prove studies of the balance of net base in the young growing rat to be technically feasible and constitute a system of reference values for animals on a standard food preparation.
Brain Glycosaminoglycans (Mucopolysaccharides) Following Intrauterine Growth Retardation
Authors: Vasan N.S. , Chase Peter
Published: September 2009

The concentration of total brain glycosaminoglycan (mucopolysaccharide) was reduced 33% in three small for gestational age (SGA) infants compared to three control infants. The three major fractions, hyaluronic acid, chondroitin sulfate, and heparan sulfate were reduced by 55, 32, and 36 % respectively in the SGA brains. The percent hyaluronidase-resistant material and the major type of hexosamine were similar in the fractions from SGA and control brains. Total hexosamine was reduced by 50% in the hyaluronic acid and heparan sulfate fractions, and increased by 35% in a third fraction of the SGA brains.
A Study of Phospholipids and Triglycerides in Several Tissues of the Rat during Fetal and Neonatal Development
Authors: Ricquier D. , Hemon P.
Published: September 2009

Gas-liquid chromatography analysis of triglyceride (TG) and phospholipid (PL) fatty acids was performed in several tissues of the rat during fetal and neonatal development and the effect of cretinism investigated. Liver and brown fat had a low TG content in the fetus, the TG of brown fat being characterized by a high proportion of saturated fatty acids; only saturated fatty acids were synthetized from glucose by brown fat fragments. The onset of suckling was followed by an immediate accumulation of TG in liver and brown fat, and the fatty acid pattern of these TG was modified, but in opposite directions; the proportion of arachidonic acid increased in the PL of all tissues. Propylthiouracil feeding of the mother from the day of birth induced an abnormal accumulation of TG in the brown adipose tissue of the rat by the time they had the syndrome of cretinism. The fatty acid pattern of these TG was similar to that of controls.
Some Aspects of Rat Metabolism in the Brown Adipose Tissue of Normal and Hypothyroid Rats during Early Postnatal Development
Authors: Hemon P.
Published: September 2009

Cretinism induced by treatment with propylthiouracil was observed to be accompanied by an accumulation of fat in the brown adipose tissue of developing rats. Several aspects of fat metabolism were subsequently investigated and in comparison with euthyroid animals the following anomalies were found. (1) The lipolytic and respiratory responses of the tissue to norepinephrine in vitro were impaired, but the lipolytic response to dibutyryl-cyclic AMP was subnormal. (2) The development of the mitochondria was also impaired, isolated mitochondria having, however, normal respiratory rates. (3) The activity of lipogenic enzymes was reduced to a low level. These anomalies can explain the accumulation of fat in the tissue, but their exact cause requires further investigations owing to the complexity of cretinism.
Lung Lecithin Biosynthesis in the Nonhuman Primate Fetus: Determination of the Primary Pathway in vivo
Authors: Farrell Philip M. , Epstein Michael F. , Fleischman Alan R. , Oakes Gary K. , Chez Ronald A.
Published: September 2009

The two pathways for denovo lecithin (phosphatidylcholine) biosynthesis, choline incorporation (I) and phosphatidylethanolamine methylation (II), were examined simultaneously in lung and other tissues of Rhesus monkey fetuses. Cannulation of inter-placental fetal vessels permitted studies on the intrauterine fetus without disruption of fetal-placental-maternal-amniotic fluid anatomic integrity. In contrast to observations with indirect techniques in the same species, direct measurement of the incorporation of isotopic precursors (3H-choline and 14C-ethanolamine) into lecithin indicated that pathway I predominates by 100-fold over PE methylation in pulmonary lecithin synthesis. Fetal liver, brain, and kidney also showed 10–70-fold, greater choline incorporation than methylation activity. Measurement of lung phosphatidylcholine production via the two pathways in acidemic fetuses (umbilical venous pH < 7.20) demonstrated marked inhibition of pathway I, but not II. It is concluded that the choline pathway is the major mechanism of lung lecithin synthesis in fetal primates and that this pathway is pH sensitive in vivo.
Studies on Experimental Hypotrophy in the Rat III. Plasma Insulin and Glucagon
Authors: Girard J.R. , Chanez C. , Kervran A. , Tordet-Caridroit C. , Assan R.
Published: September 2009

Insulin and glucagon have been measured in the plasma of rats with intrauterine growth retardation (IUGR) and their littermate controls. A lower plasma insulin and a higher plasma glucagon were observed in IUGR term rat fetuses. After birth there was no difference in the circulating level of insulin and glucagon in IUGR rats and their littermate controls. It is concluded that postnatal hypoglycemia of IUGR rat did not result from an impaired glucagon secretion or an increased insulin secretion.
Blood Lipids during Normal and Early Weaning in Rats
Authors: Palkovič Michal , Škottová Nina , Hoštacká Anna
Published: September 2009

In young rats reared with their mothers, a gradual increase of serum cholesterol, triglycerides, phospholipids and total lipids was found between the 7th and the 18th to 22nd postnatal day. Then the concentrations of lipids gradually decrease. Early weaning at the 18th postnatal day causes a precocious decrease of the concentration of all studied lipids in blood so that their values on days 22 and 26 are significantly lower than in animals weaned on the 30th postnatal day. The body weight of early weaned rats decreases only slightly and returns to normal by the 30th day. The changes in serum lipids after early weaning are caused by differences in the amount of cholesterol and other lipids in breast milk, in comparison with those in the standard laboratory diet. Perhaps they may participate in disturbing the homeostatic equilibrium of cholesterol in early weaned rats.
Adenylate Cyclase Activity in Human Tissues
Authors: Constantopoulos A. , Xypolita A. , Matsaniotis N.
Published: September 2009

Adenylate cyclase activity in liver, lung, pancreas, and heart ventricle, from full-term and premature newborns has been assayed. Of all tissues studied, heart had the highest activity. Fluoride 10 mM stimulates adenylate cyclase in all tissues. Glucagon evoked a small activation of liver adenylate cyclase.
A Study of the Permeability of the Guinea Pig Placenta to Citrate Using Recirculating Placental Perfusion Technique
Authors: Fenton Enid , Britton H.G. , Nixon † D.A.
Published: September 2009

The role of the guinea pig placenta in fetal citrate metabolism has been studied by perfusing the placenta in situ. The initial citrate concentrations in the perfusate plasma were lower than in the maternal plasma but rose progressively until, in some cases, they exceeded those in the mother. The rise was uninfluenced by intravenous administration of citrate to the mother. Citrate therefore does not enter the perfusate by simple diffusion from the maternal compartment, it may be synthesised within the placenta. From the rate of accumulation of citrate in the perfusate, the supply to the fetus was calculated to be small compared to the fetal metabolic rate. Citrate added to the perfusate became distributed in a space similar to the extracellular space and no change occurred in maternal citrate concentrations. Thus, the placenta does not appear to metabolise citrate or allow transport to the mother.
Influence of Oxytocin and Meperidine on the Isolated Human Umbilical Artery
Authors: Yao Alice C. , Nergårdh Arne , Boréus Lars
Published: September 2009

The influence of oxytocin and meperidine on responses of the isolated umbilical artery to acetylcholine (ACh) and/or 5-hydroxytryptamine (5-HT) was investigated. 32 preparations from 21 normal full-term deliveries were utilized. The Bunce double-blade hemostat provided an excellent means to collect cord specimens with the least postpartal changes. A method of simultaneously measuring the resistance to flow and longitudinal tension in the perfused artery was found to be a sensitive way to register functional responses. Results showed that oxytocin enhanced the response of the umbilical artery to ACh and 5-HT while meperidine blocked the constriction produced by 5-HT. Both these effects lasted from 30 min to more than 2 h and were reversible.
Alterations in Fetal Heart Rate and ECG Correlated to Glycogen, Creatine Phosphate and ATP Levels during Graded Hypoxia
Authors: Rosén K.G. , Isaksson O.
Published: September 2009

The depletion of glycogen, creatine phosphate and ATP in the fetal heart, liver and brain was studied in 40 mature guinea pig fetuses acutely exteriorized and submitted to a graded hypoxia. A strong linear correlation was found between an ECG scoring system, taking the severity of the ST-T changes into account, and the depletion of heart glycogen and creatine-P. ATP was unaffected until glycogen was almost depleted (25 % of initial value). At this point, brain and liver glycogen were also severely affected. Bradycardia (AV-block, type II) was strongly correlated to failing myocardial metabolism. It is concluded that the changes in the fetal ECG pattern could be regarded as a sign of myocardial glycolysis and early hypoxic stress.
Reactivity of Neonatal Canine Aortic Strips
Authors: Gray Sarah D.
Published: September 2009

To determine whether vascular reactivity in the young animal is significantly different from that of the mature animal, helical strips of thoracic aorta were suspended in an organ bath of Krebs bicarbonate solution, and isometric tension was measured. The effects of norepinephrine, phenylphrine, tyramine, and KCl were studied. The neonatal vascular strips were less sensitive than adult strips to the adrenergic agents, but responsiveness to KCl was comparable in both groups.
Metabolic Rate and O2 Consumption in Newborns during Different States of Vigilance
Authors: Stabell U. , Junge M. , Fenner A.
Published: September 2009

In 135 asymptomatic newborn infants, 1–53 days of age, body weight 1,820–4,120 g, indirect calometry was performed. According to the state of wakefulness the infants showed during the testing procedure, they were divided into four groups of vigilance (V1–V4). Metabolic rate and oxygen consumption showed similar results between groups V1, V2 and V3 (deep sleep; REM sleep; wakefulness with no muscular activity). V4 infants (with muscular activity) had a higher metabolic rate and O2 consumption. Correlation between metabolic rate and body surface area is similar in V2 and V3 but shows a steeper slope in the V1 group. It is speculated that central regulatory mechanisms may account for this difference.
Electrophoretic and Biometric Analysis of Serum Proteins of Newborn Babies
Authors: Hevér Ö. , Vadász G. , Brunner P. , Csáki P.
Published: September 2009

The average values and scatter of total protein and serum protein separated by paper electrophoresis of umbilical artery blood sampled at 130 normal deliveries, were determined. The distribution of the values was examined by means of a dot diagram. On the basis of the examination of an international standard preparation the reproducibility of the results is stated.
Separation and Characterization of Red Blood Cells from Newborns and Infants during the First Trimenon of Life by Means of a Dextran Density Gradient
Authors: Schmidt Gunter , Gross Johann , Grauel Ludwig , Ihle Wolf , Syllm-Rapoport Ingeborg
Published: September 2009

Longitudinal studies on the density of erythrocytes and reticulocytes were performed by means of the isopyknic density gradient centrifugation in dextran on three mature newborns and six premature infants during the first 3 months of life. Striking changes of the density distribution curves of red blood cells took place during the first trimenon. Median density (D50) reached its maximum between the 7th and 28th day of life. D50 of reticulocytes was lower than that of the total red blood cell population and shows similar changes to the whole cell population during the first trimenon after birth. Based on the close relationship between D50 and the percentage of lightest cells, the evaluation of the percentage of the lightest cells was recommended as a simple test to study the changes in median density.
Early Postnatal Development of the Intestine in Progeny of Protein-Deprived Rats
Authors: Shrader Ruth E. , Ferlatte Millie I. , Zeman Frances J.
Published: September 2009

Development of the small intestine was studied in newborn, and 4-, 8-, and 12-day-old young of rats fed diets, during gestation, containing 24 or 4 % casein as the source of protein. Newborn prenatally protein-deprived rats had shorter, narrower intestines, reduced numbers of villi per unit length, shorter villi, and reduced numbers of absorptive cells and crypt cells. These differences had disappeared by the age of 12 days in adequately fed pups that had survived to that age.
Plasma Renin Activity in Sheep Pregnancy after Fetal or Maternal Nephrectomy
Authors: Oakes Gary K. , Fleischman Alan R. , Catt Kevin J. , Chez Ronald A.
Published: September 2009

The effect of bilateral fetal or maternal nephrectomy on basal and diuretic-stimulated plasma renin activity (PRA) was examined in 9 chronically catheterized Dorset sheep. After fetal nephrectomy, there was an initial rapid decrease in fetal PRA with t½ of 42–84 min, followed by a slower decrement with t½ 350–720 min. There was no change in maternal PRA during this period. Similarly, after maternal nephrectomy, the decrease in maternal PRA had two exponential components and there was no associated change in fetal PRA. These data, and the maternal and fetal PRA responses to intravenous furosemide, have demonstrated that renin does not cross the sheep placenta and that fetal PRA is independent of the maternal PRA level.
Differential Responses to Prenatal Malnutrition among Neonatal Rats
Authors: Zamenhof Stephen , Guthrie Donald
Published: September 2009

Female rats were fed (A) protein-restricted diet 1 month prior to mating and throughout pregnancy, or (B) protein-free diet during 10–20 days of pregnancy. At birth, four parameters of the offspring, body weight, cerebral weight, cerebral DNA, and cerebral protein were well correlated with each other, and were significantly lower than in the controls fed stock diet. The malnourished population had on the average 30–70% Outstanding low’ individuals (parameter values more than 2 SD below the mean of the control); this is 13–20 times more than in the control. Even in malnourished populations a certain number of individuals escaped malnutrition (parameter values not lower than the mean of the control): they appear to be those which in normal populations would be well above the average (1.2–2.1 SD), but now, because of prenatal malnutrition, were merely just about average. These individuals escaped malnutrition not by taking advantage of their littermates: the latter, though malnourished, were still better than the average in the malnourished group. The mechanisms by which some of the malnourished females differentially provide enough nutrients for one of their fetuses, and more than the average for its littermates, may involve differential mobilization of maternal nutrient reserves among individual mothers, as well as differential blood supply to individual placentas or placental transfer to individual fetuses.