bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo microdialysis studies of age‐related alterations in potassium‐evoked overflow of dopamine in the dorsal striatum of Fischer 344 rats
Authors: Stanford John A. , Giardina Karen , Gerhardt Greg A. 
Published: July 2002

AbstractIntracerebral microdialysis was used to measure basal levels and potassium (K+)‐stimulated overflow of dopamine (DA), homovanillic acid (HVA) and dihydroxyphenylacetic acid (DOPAC), in the dorsal striatum of young (6 months) and aged (24 months) Fischer 344 (F344) rats. Basal levels of HVA were lower in aged rats whereas basal DA and DOPAC did not differ significantly between the two groups. The administration of three low to moderate doses of K+ (10, 25, and 50 mM) through the microdialysis probe for one collection period revealed differences between the two age groups of F344 rats. DA overflow increased in a dose‐dependent manner in the young but not aged rats. Extracellular levels of DOPAC and HVA decreased during the K+ stimulation and there was a significant difference in the changes in HVA produced by K+ stimulation in the young vs aged animals. These data support the hypothesis that low to moderate doses of K+ may be necessary to demonstrate age‐related differences in K+‐evoked DA overflow, since previous microdialysis studies using higher doses have not reported age‐related differences in DA overflow.
PSA‐NCAM: an important regulator of hippocampal plasticity
Authors: Cremer H. , Chazal G. , Lledo P.M. , Rougon G. , Montaron M.F. , Mayo W. , Le Moal M. , Abrous D.N. 
Published: July 2002

AbstractThe Neural Cell Adhesion Molecule (NCAM) serves as a temporally and spatially regulated modulator of a variety of cell‐cell interactions. This review summarizes recent results of studies aimed at understanding its regulation of expression and biological function, thereby focussing on its polysialylated isoforms (PSA‐NCAM). The detailed analysis of the expression of PSA and NCAM in the hippocampal mossy fiber system and the morphological consequences of PSA‐NCAM deficiency in mice support the notion that the levels of expression of NCAM are important not only for the regulation and maintenance of structural changes, such as migration, axonal growth and fasciculation, but also for activity‐induced plasticity. There is evidence that PSA‐NCAM can specifically contribute to a presynaptic form of plasticity, namely long‐term potentiation at hippocampal mossy fiber synapses. This is consistent with previous observations that NCAM‐deficient mice show deficits in spatial learning and exploratory behavior. Furthermore, our data points to an important role of the hypothalamic–pituitary–adrenal axis, which is the principle adaptive response of the organism to environmental challenges, in the control of PSA‐NCAM expression in the hippocampal formation. In particular, we evidence an inhibitory influence of corticosterone on PSA‐NCAM expression.
Remarkable Antiagglomeration Effect of a Yeast Biosurfactant, Diacylmannosylerythritol, on Ice‐Water Slurry for Cold Thermal Storage
Authors: Kitamoto Dai , Yanagishita Hiroshi , Endo Akira , Nakaiwa Masaru , Nakane Takashi , Akiya Takaji 
Published: July 2002

AbstractAntiagglomeration effects of different surfactants on ice slurry formation were examined to improve the efficiency of an ice‐water slurry system to be used for cold thermal storage. Among the chemical surfactants tested, a nonionic surfactant, poly(oxyethylene) sorbitan dioleate, was found to show a greater antiagglomeration effect on the slurry than anionic, cationic, or amphoteric surfactants. More interestingly, diacylmannosylerythritol, a glycolipid biosurfactant produced by a yeast strain of Candida antarctica, exhibited a remarkable effect on the slurry, attaining a high ice packing factor (35%) for 8 h at a biosurfactant concentration of 10 mg/L. These nonionic glycolipid surfactants are likely to effectively adsorb on the ice surface in a highly regulated manner to suppress the agglomeration or growth of the ice particles. This is the first report on the utilization of biosurfactant for thermal energy storage, which may significantly expand the commercial applications of the highly environmentally friendly slurry system.
Antibiotic resistance in Streptococcus pneumoniae isolated from children
Authors: Nasrin D , Collignon PJ , Wilson EJ , Pilotto LS , Douglas RM 
Published: July 2002

Objective: To determine the level of antibiotic resistance in pneumoniae (S. pneumoniae) isolated from nasal swabs of healthy children.Method: Cross‐sectional community survey.Setting: Survey was undertaken in general practice settings in Canberra during March and April 1998.Subjects: Four hundred and sixty‐one children under 3 years of age enrolled in a general practice trial of clinical practice guidelines for antibiotic use.Outcome measures: Resistance to penicillin, erythromycin, co‐trimoxazole, tetracycline, chloramphenicol and cefotaxime among the isolates of S. pneumoniae.Results: A total of 461 nasal swabs were collected and S. pneumoniae was isolated from 171 (37.1%). Penicillin resistance was found in 12.3% of these isolates, with high level resistance in 0.6%. Resistance rates were higher for cotrimoxazole (44.4%) and erythromycin (18.1%) than for penicillin. Multidrug resistance was found in 19% of these isolates. There was a significant association between the attendance at a day care centre and carriage of pneumococcus (53%vs 32%, odds ratio (OR) 2.4, 95% confidence interval (CI)1.5–3.7, P < 0.001). Children who attended day care centres and had received antibiotics during the 4 months prior to swab collection were three times more likely to carry an antibiotic‐resistant isolate than children who had neither attended a day care centre nor received antibiotics (68%vs 40%, OR 3.1, 95% CI 1.2–8.4, P = 0.02).Conclusion: The level of antibiotic resistance in pneumococci from healthy children was of concern. Carriage of pneumococcus was significantly higher in children who attended a day care centre. Resistance was significantly correlated with antibiotic use in combination with day‐care attendance. These findings warrant more judicious use of antibiotics in children.
Naratriptan as Short‐Term Prophylaxis of Menstrually Associated Migraine: A Randomized, Double‐Blind, Placebo‐Controlled Study
Authors: Newman L. , Mannix L.K. , Landy S. , Silberstein S. , Lipton R.B. , Putnam D.G. Pait , Watson C. , Jöbsis M. , Batenhorst A. , O'Quinn S. 
Published: July 2002

Objective.—To determine the efficacy of naratriptan 1‐mg and 2.5‐mg tablets twice daily compared with placebo as short‐term prophylaxis of menstrually associated migraine.Background.—Approximately 60% of women with migraine report headaches associated with their menstrual cycles. Results from an open‐label study suggest that short‐term administration of sumatriptan is useful in the prophylaxis of menstrually associated migraine.Methods.—A randomized, double‐blind, three‐arm, parallel‐group, placebo‐controlled study was conducted in women aged 18 years or older with a history of migraine with or without aura, as defined by the International Headache Society, of at least 6 months. Two dose strengths of naratriptan (1 mg, 2.5 mg) or identical‐appearing placebo tablets (1:1:1) were administered twice daily for 5 days starting 2 days prior to the expected onset of menses across four perimenstrual periods. End points included the number of menstrually associated migraines, total migraine days, peak headache severity, lost work/activity time, migraine‐related quality of life, and incidence of adverse events.Results.—Overall, the intent‐to‐treat population comprised 206 women (naratriptan 1 mg, n = 70; naratriptan 2.5 mg, n = 70, and placebo, n = 66); 171 women treated four perimenstrual periods. Significantly more perimenstrual periods per subject treated with naratriptan, 1 mg, were headache‐free compared with placebo (50% versus 25%, P = .003). Naratriptan, 1 mg, significantly reduced the number of menstrually associated migraines (2.0 versus 4.0, P < .05) and menstrually associated migraine days (4.2 versus 7.0, P  <  .01) compared with placebo. More patients treated with naratriptan, 1 mg, were headache‐free across all treated perimenstrual periods compared with placebo (23% versus 8%). No difference in headache severity was observed in breakthrough headaches. The incidence and severity of adverse events was similar across treatment groups. Naratriptan, 2.5 mg, was not statistically superior to placebo for any measure.Conclusions.—Naratriptan, 1 mg, with tolerability similar to placebo, is an effective, short‐term, prophylactic treatment for menstrually associated migraine.
Observations of dust trapping phenomena in the TRISTAN accumulation ring and a study of dust removal in a beam chamber
Authors: Saeki Hiroshi , Momose Takashi , Ishimaru Hajime 
Published: July 2002

Using a gamma-ray detector and a television camera system for synchrotron light, high-energy bremsstrahlung and horizontal growth of the synchrotron light source were observed when sudden decrease in the electron-beam lifetime occurred due to dust trapping in the electron beam. Two types of beam current losses were found; one was a continuous beam current loss, and the other was a short-term beam current loss. High-energy bremsstrahlung at a location was observed in a short time and after that, the bremsstrahlung was not detected in spite of the occurrence of dust trapping phenomena. The fact suggests motions of the trapped dust particles in the longitudinal directions. Materials collected in the beam chamber are dust particles from ion pumps and dust particles made during the beam chamber processing for welding. Most of the collected dust particles were less than 2 mm in size and surfaces of some dust particles were melted with the electron beam. Simple analysis was carried out for the conditions necessary for a dust particle to be trapped, for motions of the trapped dust particle, and for interactions between the trapped dust particle and the electron beam. The analysis showed that a dust particle less than 3 mm in size, made of Al, can be trapped and that the trapped dust particle can move in the vertical and longitudinal directions.
The analysis also suggested that a dust particle in size of about 2 mm can be continuously trapped around the electron beam without being destroyed by the electron beam. Furthermore, the analysis explained the difference between the two types of beam current losses observed in the ring. Experiments which simulate the electron beam using a Cu wire in an evacuated beam chamber show that a dust particle (less than 70 μm) is trapped sufficiently. The experiments also coincide with theory for an attractive force acting to a conducting small particle. The calculated electric field of the electron beam and the calculated electric charge of dust particles given through the photoelectric effect in the TRISTAN accumulation ring are 100 times and 104–106 times higher than those of the simulated experiments, respectively. In the ring, the attractive force caused with the average electric field and with the expected charge is 10–103 times larger than that of the simulated experiments. Therefore, a dust particle (less than 2 mm) can be trapped sufficiently. An electrostatic dust collector using an electron beam and an electrostatic force are effective in removing all of the sample dust particles in the test chamber for the simulated experiments. A method to remove trapped dust particles using electrostatic electrodes is also discussed. It is expected that such electrodes can be useful for trapped dust particles moving in a longitudinal direction.
On the behavior of velocity gradient tensor invariants in direct numerical simulations of turbulence
Authors: Cantwell Brian J. 
Published: July 2002

Studies of direct numerical simulations of incompressible, homogeneous, and inhomogeneous turbulence indicate that, in regions of high kinetic energy dissipation rate, the geometry of the local velocity gradient field has a universal character. The velocity gradient tensor satisfies the nonlinear evolution equation (dAij/dt)+AikAkj−1/3 (AmnAnm)δij=Hij where Aij=∂ui/∂xj and the tensor Hij contains terms involving the action of cross derivatives of the pressure field and viscous diffusion of Aij. The restricted Euler equation corresponding to Hij=0 can be solved in closed form [Cantwell, Phys. Fluids A 4, 782 (1992)] and the solution has the property that, for any initial condition, Aij(t) evolves to an asymptotic state of the form Aij(t)≂Kij[R(t)]1/3 where R(t) is a function which becomes singular in a finite time and Kij is a constant matrix. A number of the universal features of fine-scale motions observed in direct numerical simulations are reproduced by Kij.
In the simulation studies the first invariant of Aij is zero by incompressibility. The second and third invariants, Q and R, are determined at every grid point in the flow and the entire data set is cross-plotted to search for significant features in the space of tensor invariants. Such features can then be associated with corresponding local flow structures in physical space. When a variety of incompressible simulations are studied, scatter plots of Q vs R reveal that a fairly significant fraction of the data lies in the lower right quadrant. This is consistent with behavior predicted by the restricted Euler solution. However, the bulk of the data lies more or less uniformly distributed in a slightly elliptical region about the origin. In a direct numerical simulation of a plane, time-developing, mixing layer a small fraction of the data collects along a very pronounced, nearly straight, ridgeline extending into the upper left quadrant. This data can be traced to regions with local vorticity much larger than the local strain lying within streamwise rib vortices which connect adjacent spanwise rollers in the mixing layer simulation. Neither the predominant tendency for Q and R to lie near the origin nor the possibility for Q and R to lie far from the origin in the upper left quadrant are predicted by the restricted Euler solution. The purpose of this paper is to show that, by relaxing the assumption Hij=0 while retaining a model of dAij/dt motivated by the asymptotic form of the restricted Euler solution, one can begin to account for these features of the (Q,R) scatter plots. The results suggest that the velocity gradient tensor in three-dimensional flow tends to evolve toward an attractor in the space of tensor invariants. A significant feature of the model is that, although Hij≠0, singular behavior of Aij(t) can still occur along specific paths in the (Q,R) plane corresponding to zero values of the discriminant of Hij.
Cross‐national changes in time‐use: some sociological (hi) stories re‐examined
Authors: Sullivan Oriel , Gershuny Jonathan 
Published: July 2002

ABSTRACTThe paper addresses some macro‐sociological questions about changes in broad categories of time‐use. The focus is on large‐scale cross‐national time trends from developed countries in paid and unpaid work, and leisure. Reference is made to some well‐known sociological and historical accounts of such change, and to the fact that time‐use diary data has only relatively recently become available for analysing trends over time. The data used are drawn from a comparative cross‐time data archive held by the Institute for Social and Economic Research at Essex University, comprising successive time‐use diary surveys from a range of industrialized countries collected from the 1960s to the 1990s. The time use evidence suggests relative stability in the balance between work and leisure time over the period covered by the analyses. Some alternative explanations are advanced for why there seems to be a gap between this evidence and, on the one hand, the burgeoning literature in both academic and popular media addressing the ‘time famine’ and, on the other, people's professed experience of what is happening to their time.
Causes and correlates of adolescent drug abuse and implications for treatment
Authors: SPOONER CATHERINE 
Published: July 2002

AbstractOn the basis of the literature, the following risk factors for drug abuse by adolescents were identified: biological predisposition to drug abuse; personality traits that reflect a lack of social bonding; a history of low quality and consistency of family management, family communication, family relationships and parental role‐modelling, a history of being abused or neglected; low socio‐economic status; emotional or psychiatric problems; significant stressors and/or inadequate coping skills and social supports; inadequate social skills; history of associating with drug‐using peers, rejection by prosocial peers due to poor social skills; a history of low commitment to education, failure at school; a history of anti‐social behaviour and delinquency and early initiation to drug use. Models for conceptualizing the aetiology of drug abuse are discussed, namely Jessor's problem behaviour syndrome and Rhodes & Jason's Social Stress Model. It is clear that the path to drug abuse is complex, so simple solutions to the problem are unlikely to be effective. [Spooner C. Causes and correlates of adolescent drug abuse and implications for treatment. Drug Alcohol Rev 1999;18:453–475]
A Metastable Intermediate State of Microtubule Dynamic Instability That Differs Significantly between Plus and Minus Ends
Authors: Tran P.T. , Walker R.A. , Salmon E.D. 
Published: July 2002

The current two-state GTP cap model of microtubule dynamic instability proposes that a terminal crown of GTP-tubulin stabilizes the microtubule lattice and promotes elongation while loss of this GTP-tubulin cap converts the microtubule end to shortening. However, when this model was directly tested by using a UV microbeam to sever axoneme-nucleated microtubules and thereby remove the microtubule's GTP cap, severed plus ends rapidly shortened, but severed minus ends immediately resumed elongation (Walker, R.A., S. Inoué, and E.D. Salmon. 1989. J. Cell Biol. 108: 931–937).
To determine if these previous results were dependent on the use of axonemes as seeds or were due to UV damage, or if they instead indicate an intermediate state in cap dynamics, we performed UV cutting of self-assembled microtubules and mechanical cutting of axoneme-nucleated microtubules. These independent methods yielded results consistent with the original work: a significant percentage of severed minus ends are stable after cutting. In additional experiments, we found that the stability of both severed plus and minus ends could be increased by increasing the free tubulin concentration, the solution GTP concentration, or by assembling microtubules with guanylyl-(α,β)-methylene-diphosphonate (GMPCPP).
Our results show that stability of severed ends, particularly minus ends, is not an artifact, but instead reveals the existence of a metastable kinetic intermediate state between the elongation and shortening states of dynamic instability. The kinetic properties of this intermediate state differ between plus and minus ends. We propose a three-state conformational cap model of dynamic instability, which has three structural states and four transition rate constants, and which uses the asymmetry of the tubulin heterodimer to explain many of the differences in dynamic instability at plus and minus ends.
Dismantling Cell–Cell Contacts during Apoptosis Is Coupled to a Caspase-dependent Proteolytic Cleavage of β-Catenin
Authors: Brancolini Claudio , Lazarevic Dean , Rodriguez Joe , Schneider Claudio 
Published: July 2002

Cell death by apoptosis is a tightly regulated process that requires coordinated modification in cellular architecture. The caspase protease family has been shown to play a key role in apoptosis. Here we report that specific and ordered changes in the actin cytoskeleton take place during apoptosis.
In this context, we have dissected one of the first hallmarks in cell death, represented by the severing of contacts among neighboring cells. More specifically, we provide demonstration for the mechanism that could contribute to the disassembly of cytoskeletal organization at cell–cell adhesion. In fact, β-catenin, a known regulator of cell–cell adhesion, is proteolytically processed in different cell types after induction of apoptosis. Caspase-3 (cpp32/apopain/yama) cleaves in vitro translated β-catenin into a form which is similar in size to that observed in cells undergoing apoptosis. β-Catenin cleavage, during apoptosis in vivo and after caspase-3 treatment in vitro, removes the amino- and carboxy-terminal regions of the protein. The resulting β-catenin product is unable to bind α-catenin that is responsible for actin filament binding and organization. This evidence indicates that connection with actin filaments organized at cell–cell contacts could be dismantled during apoptosis. Our observations suggest that caspases orchestrate the specific and sequential changes in the actin cytoskeleton occurring during cell death via cleavage of different regulators of the microfilament system.
A hierarchy of thin sets related to the boundedness of trigonometric series
Authors: Eliaš Peter 
Published: July 2002

We study the family

B

0

\mathcal {B}_0

of the sets on which some series of the form

∑

k
∈

N

|
sin
⁡
π

n
k

x
|

\sum _{k\in \mathbb {N}}\left |\sin \pi n_kx\right |

is uniformly bounded. We show that the families

B

0
c

\mathcal {B}_0^c

of all sets admitting the boundary

c
c

form a hierarchy which is incontinuous with respect to the operations of intersection and union.
A simple proof of Bailey’s very-well-poised ₆𝜓₆ summation
Authors: Schlosser Michael 
Published: July 2002

We give elementary derivations of some classical summation formulae for bilateral (basic) hypergeometric series. In particular, we apply Gauß’

2

F
1

_2F_1

summation and elementary series manipulations to give a simple proof of Dougall’s

2

H
2

_2H_2

summation. Similarly, we apply Rogers’ nonterminating

6

ϕ
5

_6\phi _5

summation and elementary series manipulations to give a simple proof of Bailey’s very-well-poised

6

ψ
6

_6\psi _6

summation. Our method of proof extends M. Jackson’s first elementary proof of Ramanujan’s

1

ψ
1

_1\psi _1

summation.
Commutator inequalities associated with the polar decomposition
Authors: Kittaneh Fuad 
Published: July 2002

Let

A
=
U
P

A=UP

be a polar decomposition of an

n
×
n

n\times n

complex matrix

A
A

. Then for every unitarily invariant norm

|

|

|

⋅

|

|

|

|||\cdot |||

, it is shown that
\[

|

|

|

|

U
P
−
P
U

|

2

|

|

|

≤

|

|

|

A
∗

A
−
A

A
∗

|

|

|

≤
‖
U
P
+
P
U
‖

|

|

|

U
P
−
P
U

|

|

|

,

|||\, |UP-PU|^2||| \le |||A^*A-AA^*|||\le \|UP+PU\|\,|||UP-PU|||,

\]
where

‖
⋅
‖

\|\cdot \|

denotes the operator norm. This is a quantitative version of the well-known result that

A
A

is normal if and only if

U
P
=
P
U

UP=PU

. Related inequalities involving self-commutators are also obtained.