bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delinquency and Substance Use among Gang‐Involved Youth: The Moderating Role of Parenting Practices
Authors: Walker-Barnes Chanequa J. , Mason Craig A. 
Published: January 2005

AbstractThis study uses longitudinal data from an ethnically diverse sample of 300 ninth grade students to examine the moderating effect of parenting practices upon the relationship between gang involvement and adolescent problem behavior. Results of hierarchical linear modeling indicate that gang involvement is a highly significant positive predictor of each of three categories of problem behavior (minor delinquency, major delinquency, and substance use). Three of the four parenting variables (behavioral control, psychological control, parent–adolescent conflict, and warmth) are found to moderate the relationship between gang involvement and problem behavior, with the most consistent effects found for behavioral control and warmth. These findings indicate that intervention efforts aimed at reducing the impact of gang involvement on adolescent development should consider factors that may decrease the deleterious behavioral outcomes associated with youth gangs.
Central and peripheral neurochemical alterations and immune effects of prenatal ethanol exposure in rats
Authors: Clausing Peter , Ali Syed F. , Taylor Laventrice D. , Newport Glenn D. , Rybak Susanne , Paule Merle G. 
Published: January 2005

AbstractIn contrast to the well known effects of prenatal ethanol exposure on the central nervous system, data about its peripheral effects are scarce. Here, Sprague‐Dawley rats were fed a liquid diet (gestational days 0–20) containing 36% ethanol‐derived calories (EDCs, group H) or were pair‐fed with 18% EDCs (group L) or 0% EDCs (group C. On postnatal day 20, one male and one female from each of 10 litters per group were killed. Norepinephrine (NE) was analyzed in the frontal cortex, spleen and thymus, and dopamine, 5‐hydroxytryptamine (serotonin, 5‐HT) and their metabolites 3,4‐dihydroxyphenylacetic acid, homovanillic acid (HVA) and 5‐hydroxyindoleacetic acid (5‐HIAA) were analyzed in the striatum by high‐performance liquid chromatography with electrochemical detection. Lymphocyte subpopulations in the spleen and thymus were also assessed in half of these litters. Significant decreases in splenic NE concentration were seen in both sexes of group H (males 27%, females 28%). Decreases in striatal 5‐HT and 5‐HIAA of group H subjects appeared to be sex specific (only females were significantly affected: 23% decrease in 5‐HT, 37% decrease in 5‐HIAA). Pronounced, dose‐dependent reductions in T cell percentages were observed in both the thymus and spleen. Splenic CD8+and CD4+cell percentages were positively correlated with the splenic NE concentrations. It is concluded that the decreases seen in splenic T cell percentages subsequent to prenatal ethanol exposure may be caused, at least partially, by impaired noradrenergic control of this organ.
DiI labeling and homeobox gene Islet‐1 expression reveal the contribution of ventral neural tube cells to the formation of the avian trigeminal ganglion
Authors: Sohal G.S. , Bockman D.E. , Ali M.M. , Tsai N.T. 
Published: January 2005

AbstractCells of the neural tube are thought to be committed to form only the central nervous system, whereas the peripheral nervous system is believed to be derived from neural crest cells and from placodes, which are specialized regions of the surface ectoderm. Neural crest cells arise early from the dorsal part of the neural tube. The possibility that after emigration of the neural crest cells, another population of cells arising from the ventral part of the neural tube also emigrates via a different route was examined. Here we report that, after labeling cells of the ventral neural tube in the rostral hindbrain of E3 duck embryos with DiI, they were later found in the trigeminal ganglion of the fifth cranial nerve. A trail of labeled cells could be traced from the ventral part of the neural tube to the peripheral ganglion. Further, expression of the homeobox gene Islet‐1 in cells of the neural tube and the ganglion also indicated that some ventral neural tube cells may normally emigrate to the trigeminal ganglion. It is concluded that not all neural tube cells are committed to form the central nervous system; the ventral part of the neural tube also provides cells for the formation of the trigeminal ganglion. These results raise the possibility that the ventral neural tube may serve as an additional source of cells for the formation of various other components of the peripheral nervous system.
Structural plasticity of the adult CNS. Negative control by neurite growth inhibitory signals
Authors: Schwab Martin E. 
Published: January 2005

AbstractThe neuronal network of the adult central nervous system (CNS) retains a limited capacity for growth and structural change. This structural plasticity has been best studied in the context of lesion‐induced growth and repair. More recently, structural changes underlying functional plasticity occurring under specific physiological conditions have also been documented, in particular in the cortex and the hippocampus. Areas known for their adult plastic potential retain high levels of the growth associated protein GAP‐43, suggesting a persistence of important components of the intracellular growth machinery throughout life. Interestingly, a pronounced negative correlation exists between the levels of GAP‐43 and myelination in the adult CNS. Because CNS myelin contains potent neurite growth inhibitory membrane proteins, neurite growth, sprouting and plasticity were investigated in the spinal cord and brain in areas where oligodendrocyte development and myelin formation was experimentally prevented, or in the presence of an inhibitor neutralizing antibody (mAB‐IN‐1). In all areas, lesion‐induced or spontaneous sprouting was enhanced, in parallel with persistent high levels of GAP‐43. Thus, spontaneous sprouting of side branches occurred from retinal axons in the optic nerve in the absence of myelin, and target‐deprived retinal axons showed increased sprouting and innervation of the contralateral optic tectum in the presence of mAB IN‐1. In experimentally myelin‐free spinal cords collaterals from intact dorsal roots grew over long distances to innervate deafferented target regions following the section of three dorsal roots. Similarly, the corticospinal tract sprouted across the the midline and re‐established a dense plexus of fibres on the contralateral side of the spinal cord following section of one corticospinal tract in juvenile rats. Following bilateral dorsal hemisection of the spinal cord including both corticospinal tracts in young and adult rats, long distance regeneration of corticospinal fibres leading to significant functional improvements of locomotion and certain reflexes was induced by the neurite growth inhibitor neutralizing antibody IN‐1.
Growth stimulation and chemotropic attraction of rat retinal ganglion cell axons in vitro by co‐cultured optic nerves, astrocytes and astrocyte conditioned medium
Authors: Lucius Ralph , Young Hans Peter , Tidow Susanne , Sievers Jobst 
Published: January 2005

AbstractThe effects of explants of optic nerves of different ontogenetic ages (P0‐P14, adult), and of cultured astrocytes of various ages on the neurite regeneration of rat retinal ganglion cells (RGC) were assessed in vitro, using a three‐dimensional culture system which allows the co‐cultivation of various explants. Both co‐cultured P0‐P12 optic nerves and astrocyte cultures from P2 cerebral cortex stimulated the regeneration of neurites from the retinal explants after 3 days in culture. By contrast, P14 and older explants of the optic nerve, astrocytes from P17 optic nerve and astrocytes that had previously been grown in culture for more than 6 weeks had no effect on RGC neurite outgrowth. Moreover, both the P0–P12 optic nerve explants and the astrocytes from P2 cerebral cortex also seemed to have a chemotropic effect on the regenerating neurites, because the latter were longer on the side facing the co‐explantat. The absence of a cellular bridge between retinal and optic nerve explants suggests that the effects are mediated by astroglia‐derived diffusible neurite growth promoting factors. Accordingly, astrocyte‐conditioned medium from P2 astrocytes also stimulated the outgrowth of neurites from the retinal explants. These findings show that immature astrocytes of a limited ontogenetic period release as yet unknown diffusible neurite growth‐promoting factors which stimulate the regeneration of neurites from retinal explants.
Chronic heart failure is associated with vascular remodeling of the brachial artery
Authors: Poelzl Gerhard , Frick Matthias , Huegel Heike , Lackner Benedikt , Alber Hannes F. , Mair Johannes , Herold Manfred , Schwarzacher Severin , Pachinger Otmar , Weidinger Franz 
Published: January 2005

AbstractAims:Endothelial dysfunction has been shown to correlate with severity of congestive heart failure (CHF) and recent data suggest morphological changes of peripheral vasculature to be associated with the syndrome. We therefore investigated the hypothesis that vascular remodeling is associated with functional changes in peripheral conduit arteries and with systemic overexpression of ET‐1 in patients suffering from CHF.Methods and results:57 consecutive patients referred to the Innsbruck Heart Failure and Transplantation Program (EF=23±7%) and 16 matched controls (EF=60±5%) were studied. Flow‐mediated vasodilation (FMD), nitroglycerin‐mediated vasodilation (NMD), wall thickness (WT), and incremental elastic modulus (Einc) were assessed by high‐resolution ultrasound of the brachial artery. FMD (P=0.004) and NMD (P=0.02) were significantly higher in controls as compared to moderate and severe CHF patients. In contrast, brachial artery‐wall thickness (BA‐WT) was increased in severe CHF patients (P=0.038). BA‐WT was significantly correlated with both FMD (r=−0.28; P=0.049) and NMD (r=−0.38; P=0.003), and with the Einc (r=0.45, P=0.001). Lumen diameter was not different among groups. In patients with BA‐WT>0.31 mm, bigET‐1 was higher compared to BA‐WT<0.31 mm (P<0.05).Conclusion:CHF is associated with remodeling of the brachial artery, which is characterized by morphological, mechanical and functional changes of the vessel wall. Endothelin‐1 may play a role in the vascular remodeling process.
The Structural Characteristics of Certain Silver Films
Authors: Essig Sanford F. 
Published: January 2005

The structural characteristics of three types of silver films which have found general use as photocathode bases in television image analyzers and similar electronic devices are discussed. They are classified as mosaics and translucent films. Two types of mosaics are discussed, (1) the reduced oxide dust film, and (2) the agglomerated sputtered or evaporated film. A characteristic of the first is a wide range in particle size (&lt;1−30μ in films photographed), those below 3 microns being greatest in number. A critical temperature, approx. 600°C, is observed in reduction of the oxide films above which there is a distinct liquid phase in the silver-silver oxide system resulting in a radical change in the final film structure.
The process of agglomeration is traced from the continuous through the mosaic state in the second type film. The characteristics are a smaller and more uniform particle size than the reduced oxide type. Particle size and spacing is readily controlled and reproduced. The range in initial thickness of films investigated is approximately 0.01−0.2 microns.
The third type or translucent film is a composite consisting of a silver mosaic superposed on an electrically conducting film of relatively high light transmission. Platinum is chosen as the most suitable metal for this subfilm and is protected from destructive forces such as oxidation and alloying with the silver mosaic by an intermediate film of silica or aluminum oxide.
Ionic Mobility in Solid Dielectrics
Authors: Gemant Andrew 
Published: January 2005

1. It is assumed that ionic mobility in solid dielectrics is controlled by a combined resistance of viscosity, elasticity and solid friction.
2. Under this assumption ionic mobility under alternating electric stress is calculated. It appears from the formulae that there is a finite contribution due to ions toward both the dielectric constant and loss factor. In the range of technical and acoustical frequencies both are in first approximation independent of frequency. The loss factor, controlled by the solid friction, is equivalent to an a.c. conductivity several orders higher than the d.c. conductivity, as known from observation.
3. Applying the same conception to ionic mobility in a constant field of high intensity, it appears that ions cover only part of their travel by a viscous flow, a small fraction being due to elastic displacements. This latter increases with the field strength. The energy stored during this displacement is finally converted into vibratory kinetic energy of the ion, thus enabling it to accumulate energy and finally ionize. The theory shows that this process becomes appreciable at a field strength between 104 and 105 v/cm in agreement with observations on the increase with field strength of the conductivity.
On the Starting of Hg Vapor Discharge Tubes
Authors: Kenty Carl 
Published: January 2005

In a commercial method of starting the Cooper Hewitt Hg vapor lamp, a current of about 0.7 amp. is first made to flow in a circuit containing an inductance and a Hg vacuum switch or ``shifter.'' This shifter is then opened magnetically and the resulting arc therein is unstable and begins to go out. But the inductance acts to keep the current flowing and develops a high voltage which is impressed as a negative kick of about 1000 volts, in the average case of starting, on the Hg pool cathode of the main tube. This kick, as a result of the action of a strip of tinfoil on the outside of the cathode bulb surrounding the Hg pool edge and connected to the main anode, starts the arc. The whole process results in the transfer of nearly the entire current from the shifter arc to the main arc in a time of the order of a few microseconds. The initiation of the cathode spot is attributed to the action of a high electric field at the Hg pool edge existing between this edge and the tinfoil on the outside of the glass. In accord with this theory is the fact that anything which can be done to cause the Hg to wet the glass at the pool edge at a number of points (thereby increasing the field) such as by baking a little carborundum powder on the glass at the edge, helps starting enormously.
If the anode of the tube is disconnected, simple electroscopes show that the walls of the tube everywhere become charged to a negative potential of the order of 10,000 volts as a result of the kicks. High speed electrons are thus evidently shot up the tube. Ionization produced by these probably forms the beginning of the positive column. After initiation, the current in the tube rises to a maximum at a rate limited by the inductance in the circuit and then decreases to a low value sometimes going out altogether. This decrease is shown to be due to an extreme deficiency of Hg vapor in the tube caused by the electrical clean-up of Hg on the walls. Violent voltage surges set in across the tube at this time and a hissing noise is heard. The region of aggravated low pressure can be seen as glowing weak and reddish compared to the blue white of the rest of the tube. This appearance vanishes when, as a result of the rising vapor pressure due to heating, the hiss and surges stop. The surge period may endure many seconds in cold weather before the arc is able to pick up.
A STUDY OF LIGHT SIGNALS IN AVIATION AND NAVIGATION
Authors: Langmuir I. , Westendorp W. F. 
Published: January 2005

Visibility of point sources.—Laboratory experiments have been devised to make measurements of the visibility of light signals under conditions essentially similar to those encountered by the aviator or the navigator. Data have been collected on the direct visibility of flashing point sources of light of different colors, flash lengths and intervals, against different backgrounds; the time it takes to locate a visible beacon was studied as a function of the beacon intensity and frequency of flashing. The threshold candle power C required for visibility of a point source at distance D (cm) against a background of brightness H (candles×cm−2) is given by the empirical equation C/D2=3.5×10−9 H1/2. Colored point sources were not found to be useful except in the case of red lights with background intensities above moonlight. For an airplane approaching a beacon it is advantageous to use frequencies of flashing as high as 12 to 30 per minute, although with exceptionally clear atmosphere, lower frequencies may be better.
Visibility of diffuse light.—In a study of the visibility of flashes of diffuse light superimposed on a steady white background, white light flashes gave the best results. The sensitivity of the eye to light from point sources is from 10,000 to 170,000 times as great as from diffuse sources, this range corresponding to an increase in background brightness from 0.1 starlight up to moonlight. A selective differential photoelectric receiver is described which detects signals of modulated diffuse light of an intensity of only 4×10−11 candles×cm−2. This sensitivity is independent of the steady background brightness up to 100 times moonlight, and is from 6 to 13,000 times as great as that of the eye in the range of background intensity from darkness up to moonlight.
Diffusion of light in fog.—The greatest difficulty in transmission of light signals through fog lies in the loss of advantages of the point source. Dense fog may increase the distances at which diffuse light signals may be detected. The range depends to a considerable extent on the reflectivity of the ground. A theoretical treatment of the diffusion of light through fog, based on the scattering of the light rays by fog particles, indicates that airplanes can be guided through fog at distances of several miles by means of diffuse modulated light acting on a differential photoelectric receiver.
ELECTROKINETIC POTENTIALS. XI. THE EFFECT OF SODIUM SOAPS ON THE ELECTRIC MOMENT OF THE DOUBLE LAYER AT AN AQUEOUS-CELLULOSE INTERFACE
Authors: Bull Henry B. , Gortner Ross Aiken 
Published: January 2005

1. Electrokinetic studies of aqueous solutions of sodium formate, sodium acetate, sodium propionate, sodium butyrate, sodium caprylate, sodium oleate and sodium oxalate have been conducted at a cellulose interface with the streaming potential technique.
2. It is suggested that in interest of clearness and accuracy the attempt to express electrokinetic data in terms of ``potentials'' be abandoned and that the electric moment of the double layer, which does not require a knowledge of the magnitude of the dielectric constant, be substituted for ζ.
3. It is indicated that after the fourth carbon atom has been added the electric moment of the double layer is essentially a constant.
4. It is noted that there is no correspondence between the ionization constant of the fatty acid from which the soap is derived and its effect on the electrokinetic conditions at the interface. This indicates that hydrolysis and the resulting OH ion plays a minor role.
5. It is pointed out that the electric moment of the double layer in the case of the longer chained soaps is almost independent of the concentration whereas that of the short chained soaps are much more sensitive to increased concentration.
6. The maximum electric moment is found at about 2×10−4 normal. This is true also for a number of salts.
Potential Distributions in Large Cylindrical Disks with Partially Penetrating Electrodes
Authors: Muskat Morris 
Published: January 2005

Because of the equivalence of the pressure in a liquid bearing sand to a velocity potential, an analysis has been carried through of the potential theory of the electrical analogue of an artesian well partially penetrating a water bearing sand.
Part I. In Part I the method of analysis is illustrated by the solution of the problem of a hemispherical electrode imbedded in one of the faces of the disk. Two types of formulae are developed suitable for study of the potential distribution at small and large distances from the electrode respectively. The resistance of this system as a function of the disk thickness is computed and plotted.
Part II. In Part II is treated the more general problem of the potential distribution for a partially penetrating electrode, with a uniform flux density along the electrode surface. Separate formulae for the potential function are again derived that are convenient for discussion at small and large separations from the electrode. It is shown that they reduce in the limit of small penetrations to those of Part I and in the limit of complete penetration to well-known radial flow formulae. Expressions are also given for the stream functions corresponding to the derived potential functions. Finally it is shown that when the flux density along the electrode is assumed to be constant the potential over the electrode is far from uniform, falling sharply near the electrode extremity to a value slightly more than half of that at the top of the electrode.
Part III. The problem of physical interest in which the electrode is at uniform potential is attacked in Part III. After discussing the case of a flux density over the electrode surface increasing with distance from the top the direct method of superposing discontinuous flux density elements is finally used to obtain electrode surface potentials uniform to within 2 percent of the average surface value. The equivalence of this method to the direct solution of the integral equation for the problem is pointed out. The resistances of the disk for various electrode penetrations and disc thicknesses are then computed and plotted. From these a semi-empirical approximation is derived permitting the resistances for other cases to be derived from a single expression without the necessity of first adjusting the electrode flux distribution so that its potential be uniform.
An Inducible Targeted Tagging System for Localized Saturation Mutagenesis in Arabidopsis
Authors: Nishal Bindu , Tantikanjana Titima , Sundaresan Venkatesan 
Published: January 2005

Abstract
We describe a system of inducible insertional mutagenesis based on the Ac-Ds family of transposons for targeted tagging in Arabidopsis (Arabidopsis thaliana). In this system, the Ac and Ds elements are carried within the same T-DNA and a heat shock-inducible transposase fusion is utilized to control the levels of transposase gene expression, generating transpositions that can be subsequently stabilized without requiring crossing or segregation. We have mapped 40 single-copy lines by thermal asymmetric interlaced-PCR, which can be used as potential launch pads for heat shock mutagenesis. Using a starter line selected for detailed analysis, the efficiency of tagging over a 50-kb region in the genome was examined. Hits were obtained in the targeted genes with multiple alleles for most genes, with approximately equal numbers of hits detected in genes on either side of the T-DNA. These results establish the feasibility of our approach for localized saturation mutagenesis in Arabidopsis. This system is very efficient and much less laborious as compared to conventional crossing schemes and may be generally applicable to other plant species for which large-scale T-DNA tagging is not currently feasible.