bluuebunny/crossref_metadata_2025_split huggingface dataset:
Long‐term nigral transplants in rat striatum: An electron microscopic study
Authors: Gopinath Gomathy , Sailaja K. , Tandon P.N. 
Published: January 2005

AbstractThe substantia nigra of gestation day 14 was transplanted into the striatum of 3–4‐month‐old rats to investigate the transplants ultrastructurally at the end of 2 years, as a follow‐up to our previous studies. Transplants were of small size in all 10 specimens taken for this study. The changes observed in the transplant and in the interface region with the host striatum were: thickening of the blood vessel walls, perivascular cuffing with lymphocytes and macrophages loaded with tissue debris, degenerating neurons and hypertrophied astroglia containing dense granules indicating ageing or reaction to degeneration and glial processes. The number of surviving neurons in the transplants was small. These were smaller in size and had very few intracytoplasmic membraneous organelles. A higher content of intracytoplasmic ageing lipofuscin pigment was present than in host neurons and age‐matched nigral neurons. Synapses were few, and their number varied among transplants. Generally, the synapses were at the interface with the host tissue. The changes observed in all the 2‐year‐old transplants suggest premature ageing or a slow rejection process. Slow rejection is a possibility, because these rats are only stock‐bred, not inbred, and hence they are not completely immunologically compatible.
Neuron‐glia interrelations during migration of Purkinje cells in the mouse embryonic cerebellum
Authors: Yuasa Shigeki , Kawamura Koki , Kuwano Ryozo , Ono Katsuhiko 
Published: January 2005

AbstractThe interrelations between migratory Purkinje cells and radial glial processes were examined immunohistochemically and electron‐microscopically in the fetal mouse cerebellum. Migratory Purkinje cells identified immunochemically with anti‐spot 35 antibody were apposed to the presumed radial glial processes. Putative immature migratory Purkinje cells were apposed to the radial glial processes identified immunochemically with monoclonal antibody 1DI I or anti‐tenascin antibody. Junctional specializations related to cell adhesion were observed at the sites of contact between the immature neurons and glial processes. Furthermore, coated vesicles and coated pits were noted in the contact region. These findings support the concept of contact guidance of migratory Purkinje cells by radial glial processes through cell adhesion, and also suggest the trophic interactions occurring at the region of contact.
Effects of ischemia‐hypoxia induced by interruption of uterine blood flow on fetal rat liver and brain enzyme activities and offspring behavior
Authors: Binienda Z. , Holson R.R. , Chen F.‐X. , Oriaku E. , Kim C.S. , Flynn T.J. , Slikker W. , Paule M.G. , Feuers R.J. , Ferguson S.A. 
Published: January 2005

AbstractThe effects of acute perinatal ischemia‐hypoxia on fetal liver and brain energy metabolism, fetal brain total free fatty acid concentration and subsequent offspring behavior were investigated in rats. Ischemia‐hypoxia was induced at term either by ligation of the uterine blood vessels or submersion of the entire uterine horn in warmed saline. Fetuses of the adjacent horn served as within‐dam controls for all assessments and fetuses of dams which had not undergone the surgical stress served as independent controls for enzyme assays. Ischemia‐hypoxia was associated with reduced activity of fatty acid synthase in the liver and brain. Total free fatty acid concentration significantly increased in the fetal hypoxic brain. Pups not used for enzyme analyses were cross‐fostered for behavioral assessments. Relative to the enzymatic alterations, there were few behavioral alterations associated with ischemia‐hypoxia. At postnatal day 30, rats made hypoxic by ligation of the uterine blood vessels had decreased caudate nucleus and brain stem weights relative to within‐dam controls. At postnatal day 85, rats made hypoxic by submersion of the uterine horn had decreased olfactory bulb weight. The results of this study indicate an initial acute response to a brief period of ischemia‐hypoxia at term pregnancy in the fetal rat brain and liver.
Effect of growth factors on the in vitro growth and differentiation of early and late passage C6 glioma cells
Authors: Goya Luis , Feng Pei‐Ti , Aliabadi Samira , Timiras Paola S. 
Published: January 2005

AbstractThe effect of different hormones and growth factors was assayed on the in vitro growth and enzymatic activities of 2′,3′‐cyclic nucleotide 3′phosphohydrolase (CNP) and glutamine synthetase (GS) of rat glioma C6 cells at two different passages in culture. Young cultures (passage 26), mainly oligodendrocytic, and older cultures (passage 134), predominantly astrocytic, were treated with 10 μM dexamethasone, 20 ng/ml transforming growth factor alpha (TGFα), 10 ng/ml insulin, 20 ng/ml platelet‐derived growth factor (PDGF), and 20 ng/ml, epidermal growth factor (EGF) in serum‐free chemically defined media. In vitro growth rate was measured in terms of DNA content, by a fluorometric method of diaminobenzoic acid, and rate of DNA synthesis by 3H‐thymidine incorporation. CNP activity (marker for in vitro oligodendrocytes) and GS activity (marker for astrocytes) were determined spectrophotometrically. Dexamethasone reversibly and significantly inhibited growth of C6 glioma in early and late passages. PDGF and insulin promoted in vitro growth only in late passage but not in early passage cells, whereas EGF and TGFα did not significantly affect growth. An increase in CNP activity was observed in early passage cells under the effect of PDGF and insulin. The increase in GS activity induced by insulin and dexamethasone suggests a differentiating role for these factors in C6 glioma cells. These results further present the C6 glioma cell line as a useful model for studies on glial cell properties and responsiveness in culture and support its use in experimental aging in vitro.
Colour M‐mode velocity propagation: a glance at intra‐ventricular pressure gradients and early diastolic ventricular performance
Authors: De Boeck Bart W.L. , Oh Jae K. , Vandervoort Pieter M. , Vierendeels Jan A. , van der Aa Ronald P.L.M. , Cramer Maarten‐Jan M. 
Published: January 2005

AbstractThe physiology of early‐diastolic filling comprises ventricular performance and fluid dynamical principles. Elastic recoil and myocardial relaxation rate determine left ventricular early diastolic performance. The integrity of left ventricular synchrony and geometry is essential to maintain the effect of their timely action on early diastolic left ventricular filling. These factors not only are prime determinants of left ventricular pressure decay during isovolumic relaxation and immediately after mitral valve opening; they also instigate the generation of a sufficient intra‐ventricular pressure gradient, which enhances efficient early diastolic left ventricular filling. Accurate assessment of diastolic (dys)function by non‐invasive techniques has important therapeutic and prognostic implications but remains a challenge to the cardiologist. The evaluation of left ventricular relaxation by the standard Doppler echocardiographic parameters is hindered by their preload dependency. The colour M‐mode velocity propagation of early diastolic inflow (Vp) correlates with intra‐ventricular pressure gradients and is a largely preload independent index of ventricular diastolic performance. In this article, the physiologic background, utility and limitations of this promising new tool for the study of early diastolic filling are reviewed.
State Collaboration and Development Strategies in China: The Case of the China–Singapore Suzhou Industrial Park (1992–2002). By Alexius A. Pereira. [London and New York: RoutledgeCurzon,
2003. 189 pp. ISBN 0-415-30277-3.]
Authors: Thun Eric 
Published: January 2005

Take a drive through the Suzhou Industrial Park (SIP) and you will see what appears to be a model industrial estate: cleanly laid out roads interspersed with green parks and endless rows of factories humming with activity. There is none of the chaotic, thrown-together feel of so many Chinese industrial parks; the atmosphere is almost serene. Talk to the managers of these factories and you will hear nothing but praise for the managers of the park. Even the biggest problems – the rapidly rising cost of land, the shortage of workers – are indications of success. Surprisingly, and despite these outward appearances, the SIP was, until recently, viewed by many as a grave disappointment.The SIP was not supposed to be just another industrial park in China: it was a grand experiment. The idea was to transplant the strengths of the Singaporean model – effective bureaucratic management, world-class infrastructure and a stable business environment – to China through government co-operation. The park was a joint venture between a foreign consortium directed by the Singaporean government and a Chinese consortium consisting of local governments and centrally-controlled, state-owned enterprises. From the perspective of the Chinese government, the hope was that the SIP would provide a model of effective governance for the rest of the country at the same time as it served as an engine of growth in the Jiangsu region. From the perspective of the Singaporean government, the SIP was partly an attempt to capitalize upon its strength in management in a location with far lower costs, and partly an attempt to demonstrate the relevance of the Singaporean “model” in a Chinese context. The stakes were high for both parties.
Changing China: A Geographic Appraisal. Edited by Chiao-Min Hsieh and Max Lu. [Oxford and Boulder, CO: Westview Press, 2003. 512 pp. $48.00. ISBN 0-8133-3474-8.]
Authors: Gaubatz Piper 
Published: January 2005

One of the greatest challenges to those researching and lecturing on China today is the country's rapid rate of change. To date, there have been only a handful of timely general texts for use in English-language geography and other social science courses. These have included single authored efforts, such as Christopher Smith's China: People and Places in the Land of One Billion (1991), Frank Leeming's The Changing Geography of China (1993) and Songqiao Zhao's Geography of China: Environment, Resources, Population and Development (1994); and edited collections such as Terry Cannon and Alan Jenkins' The Geography of Contemporary China: The Impact of Deng Xiaoping's Decade (1990), Gregory Veeck's The Uneven Landscape: Geographic Studies in Post-Reform China (1991), and Robert Gamer's Understanding Contemporary China (2003). Although each of these books remains an important and valuable contribution to the literature and to the teaching of courses on China, the remarkable pace of change in China has rendered them out of date in less than a decade.In this context, it is good to see a new contribution. Using China's rapid post-1978 change as a theme, geographers Chiao-min Hsieh and Max Lu have assembled Changing China: A Geographic Appraisal, an edited collection of 26 chapters, in 500 pages. These chapters, largely written by geographers, are organized into three sections entitled “Economic changes,” “Social changes” and “Changes along China's periphery.” The primary strength of the book is its breadth. Although it addresses neither physical geography nor China's environmental issues, it does speak to a wide range of human geographic questions, from land use and agricultural development to population and economy. The majority of the chapters, with a few exceptions, are well grounded within the authors' own research foci and expertise. The most notable weakness of the book is one shared by many edited collections: that it lacks integration and a sense of dialogue between the chapters. This weakness might have been overcome through a face to face meeting of the authors, through an exchange of chapter drafts, through editorial guidance, or through more extensive section introductions and summaries by the editors. This type of integration is, of course, rare.
Intravenous anaesthetics inhibit nicotinic acetylcholine receptor‐mediated currents and Ca2+ transients in rat intracardiac ganglion neurons
Authors: Weber Martin , Motin Leonid , Gaul Simon , Beker Friederike , Fink Rainer H A , Adams David J 
Published: January 2005

The effects of intravenous (i.v.) anaesthetics on nicotinic acetylcholine receptor (nAChR)‐induced transients in intracellular free Ca2+ concentration ([Ca2+]i) and membrane currents were investigated in neonatal rat intracardiac neurons.
In fura‐2‐loaded neurons, nAChR activation evoked a transient increase in [Ca2+]I, which was inhibited reversibly and selectively by clinically relevant concentrations of thiopental. The half‐maximal concentration for thiopental inhibition of nAChR‐induced [Ca2+]i transients was 28 μM, close to the estimated clinical EC50 (clinically relevant (half‐maximal) effective concentration) of thiopental.
In fura‐2‐loaded neurons, voltage clamped at −60 mV to eliminate any contribution of voltage‐gated Ca2+ channels, thiopental (25 μM) simultaneously inhibited nAChR‐induced increases in [Ca2+]i and peak current amplitudes. Thiopental inhibited nAChR‐induced peak current amplitudes in dialysed whole‐cell recordings by ∼ 40% at −120, −80 and −40 mV holding potential, indicating that the inhibition is voltage independent.
The barbiturate, pentobarbital and the dissociative anaesthetic, ketamine, used at clinical EC50 were also shown to inhibit nAChR‐induced increases in [Ca2+]i by ∼40%.
Thiopental (25 μM) did not inhibit caffeine‐, muscarine‐ or ATP‐evoked increases in [Ca2+]i, indicating that inhibition of Ca2+ release from internal stores via either ryanodine receptor or inositol‐1,4,5‐trisphosphate receptor channels is unlikely.
Depolarization‐activated Ca2+ channel currents were unaffected in the presence of thiopental (25 μM), pentobarbital (50 μM) and ketamine (10 μM).
In conclusion, i.v. anaesthetics inhibit nAChR‐induced currents and [Ca2+]i transients in intracardiac neurons by binding to nAChRs and thereby may contribute to changes in heart rate and cardiac output under clinical conditions.

British Journal of Pharmacology (2005) 144, 98–107. doi:10.1038/sj.bjp.0705942
A Resonance Curve Method for the Absolute Measurement of Impedance at Frequencies of the Order 300 mc/Second
Authors: Chipman R. A. 
Published: January 2005

A general theory is developed, together with a simplified experimental procedure, which permits the absolute measurement of the magnitude and phase angle of any value of complex impedance, in terms of the characteristic impedance of a parallel-wire line to which the impedance to be measured is connected as one termination. The observed quantities are the shape of the resonance curve of the current in one of the line's terminations obtained by varying the line length, and the length of line for maximum current. The effects of distributed line resistance and of radiation resistance on the impedance measurements are discussed in detail. Examples are given of the measurement of the impedance of straight resistance wires, and of the resistance of ``metallized'' resistors, at a frequency of 377 mc/sec.The accuracy of the method varies considerably throughout the total range of resistance and reactance, but is high for any combination of the two from a few ohms to a few thousand ohms. The possible accuracy varies approximately inversely as the frequency. At a frequency of 300 mc/sec. an optimum accuracy of about one percent may be expected.In an appendix some experimental data on the radiation resistance of a parallel-wire line are described.
Phosphorescence of Zinc Silicate Phosphors
Authors: Fonda Gorton R. 
Published: January 2005

At low contents of the manganese activator, the decay of phosphorescence takes place in two stages. The initial stage is exponential. It is complete in less than 0.1 second and is not affected by temperature. The second stage is at a much lower intensity level. It becomes noticeable after 0.03 second and persists for more than an hour. Its speed of decay increases with temperature. At − 196°C it is completely latent. A change in the intensity of the exciting light alters proportionally the luminescence caused by each stage of decay and has no effect upon the shape of the decay curves.
About fifty times as many electrons are involved in the second stage of decay as in the first. It is assumed that the second stage is caused by the retention of electrons in a metastable state, probably one associated with the presence of lattice imperfections. The exponential decay of the first stage would result from the recombination of manganese ions, relatively in excess, with those free electrons which had not been captured in the potential cups of the metastable state.
The decay of phosphors rich in manganese is always very abrupt and at a speed which rises rapidly with increase in temperature. The course of decay can be represented by the expression p−x=a+bt except at reduced temperatures where the two stages of decay characteristic of low manganese content are observable.
Vitrification and Crystallization of Organic Cells at Low Temperatures
Authors: Goetz Alexander , Goetz S. Scott 
Published: January 2005

I. Theoretical considerations.—The conditions which determine whether a homogeneous liquid will solidify into the crystalline or into the vitreous state are discussed and a brief account of the rôle of the speed of crystallization, V, and that of grain formation, N, is given. These concepts are applied to the causes of the death due to crystallization of nondehydrated organic cells, and the physical conditions of cooling are developed under which such organisms can be solidified with a minimum of crystallization, assuring to this extent the preservation of their potential life.
II. Technical considerations.—Methods for obtaining cooling rates up to 104 deg. sec.−1 applicable to organic cells in a highly dispersed state are developed. As subject for the experiments, pure strains of yeast (Saccharomyces cerevisiae) were chosen on account of the high sensitivity to low temperatures. As death criterion, the permeability of the cells to a standard aqueous solution of methylene blue was chosen, the death rate was thus determined microphotographically or with a counting chamber. Different techniques of exposure favoring and preventing crystallization are developed.
III. Experimental results.—The rate of cooling of suspensions of living cells in aqueous media was varied from 1 to 104 deg. sec.−1 and thus conditions favoring either crystallization or vitrification of the cell plasma were produced. The death rate at an exposure of −185°C was thus varied from approximately 75 percent to approximately 3 percent. The duration of exposure at this temperature was varied from 5′ to 6000′; no appreciable influence of the time of exposure was found. The temperature to which the cells were cooled was varied from −50°C to −252°C and it was found that between −185°C and −252°C the temperature did not affect the death rate. Above app. −150°C an increase of the death rate was found, and a dependence upon the time of exposure, since the speed of crystallization begins to be appreciable. Repeated exposures of the same cells under conditions not especially favoring vitrification were studied and the integral death rate, δn (death rate after nth exposure) was investigated with respect to a constancy of the death rate (δ) at each freezing. It appears that the death rate for repeated freezings is not controlled by simple probability relations, but that other effects enter, such as weakening of cells by previous exposures and the selection of cold-resistant cells by survival.
Characteristics and Functions of Thyratrons
Authors: Hull A. W. 
Published: January 2005

The Thyratron is a tube of very low resistance (arc discharge) which can be started or prevented from starting by a grid. Its qualities are: enormous power-amplification, approximately 1011 per tube; efficiency between 95 and 99 percent at all voltages above 250; unlimited size, as regards current-capacity; high-voltage limit equal to that of the Pliotron; starting time one to six microseconds; deionization time 10 to 500 microseconds.
Use of Thyratron as switch and for power control. The controlling element may be a switch, clock, thermostat, or photo-tube; the controlled element a motor, magnet, contactor, or reactor. Typical applications of this kind of use are; turning on lamps at dusk, dispatching products to predetermined stations, cutting hot steel bars to exact length, opening doors at the approach of a person, wrapping packages, sorting beans and other articles, counting people or products, operating line or spot welding machines. By varying the phase of the grid-voltage with respect to that of the anode voltage, a smooth variation of average anode current may be obtained. A typical application is the dimming and blending of lights in theaters.
Use of Thyratron as rectifier and as inverter from direct to alternating current. Immediate objectives are frequency changing, from 60 to 25 cycles for railway and power purposes, and from 60 to 200 for spinning mills; and commutatorless motors of variable and controllable speed. A more remote but important application is d.c. transmission of power, with inversion to a.c. at the point of utilization.
Use of Thyratrons in scientific research. Applications include high-speed stroboscopes, timing devices, synchronous switches, and voltage regulators. Most interesting and promising of all is a device for counting alpha-particles, protons, and neutrons.
Viscous Resistance in Capillaries of Non-Uniform Radius
Authors: McLean D. A. 
Published: January 2005

The viscous resistance offered by a tube of varying radius to the flow of a liquid is discussed. Three cases are taken up, for which solutions assume the forms:
(1) capillary tube viscometer: η=πP/8QAL.
(2) Bingham and Murray plastometer: η=P(t−t1)/8[f3(l)−f3(l1)].
(3) apparatus for studies of wetting under dynamic conditions: γ=4ηf5(l)/t.The functions AL, f3(l), and f5(l), may be obtained from a calibration of the tube, use being made of graphical integration.