bluuebunny/crossref_metadata_2025 huggingface dataset:
Retinocollicular synaptogenesis and synaptic transmission during formation of the visual map in the superior colliculus of the wallaby (Macropus eugenii)
Authors: Flett D. L. , Lim C. H. , Ho S. M. , Mark R. F. , Marotte L. R.
Published: June 2006

Spontaneous retinal activity has been implicated in the development of the topographic map in the superior colliculus (SC) but a direct demonstration that it reaches the colliculus is lacking. Here we investigate when the retinocollicular projection is capable of transmitting information from the retina in a marsupial mammal, the wallaby (Macropus eugenii). The projection develops postnatally, allowing in vivo analysis throughout development. Quantification of retinocollicular synaptogenesis has been combined with electrophysiology of the development and characteristics of retinocollicular transmission, including in vivo and in vitro recording in the same animals. Prior to postnatal day (P) 12–14 in vitro recording detected only presynaptic activity in retinal axons in the colliculus, in response to stimulation of the optic nerve. Postsynaptic responses, comprising both N‐methyl‐d‐aspartate (NMDA) and non‐NMDA responses, were first detected in vitro at P12–14 and retinal synapses were identified. In contrast, postsynaptic responses to optic nerve stimulation could not be detected in vivo until P39, around the time that retinal axons begin arborizing. Around this age density and numbers of total synapses began increasing in the retinorecipient layers of the colliculus. By P55–64, the numbers of retinal synapses had increased significantly and density and numbers of retinal and total synapses continued to increase up to P94–99. During this time the map is undergoing refinement and degenerating axons and synapses were present. The discrepancy between in vitro and in vivo onset of functional connections raises the question of when retinal activity reaches collicular cells in the intact, unanaesthetized animal and this will require investigation.
Immunocytochemical evidence for the existence of substance P receptor (NK1) in serotonin neurons of rat and mouse dorsal raphe nucleus
Authors: Lacoste Baptiste , Riad Mustapha , Descarries Laurent
Published: June 2006

In addition to its neurotransmitter/modulator role in pain perception, substance P (SP) is involved in a regulation of mood, as antagonists of its neurokinin‐1 receptor (NK1r) have been found to have antidepressant‐like effects in humans. In rodents, treatment with NK1r antagonists has been shown to increase the firing of dorsal raphe nucleus (DRN) serotonin (5‐hydroxytryptamine, 5‐HT) neurons and to induce a desensitization of their 5‐HT1A autoreceptors, suggesting local interactions between the SP and 5‐HT systems. To search for the presence of NK1r on 5‐HT neurons of the DRN, we used light and electron microscopic immunocytochemistry, as well as confocal microscopy, after single‐ and double‐labelling of NK1r and of the biosynthetic enzyme of 5‐HT, tryptophan hydroxylase (TpOH). A significant number of 5‐HT (TpOH‐positive) cell bodies and dendrites endowed with NK1r were thus demonstrated in the caudal part of rat and mouse DRN. As visualized by electron microscopy after gold immunolabelling, NK1r was mostly cytoplasmic in 5‐HT neurons, while predominating on the plasma membrane in the case of TpOH‐negative dendrites. The proportion of NK1r observed on the plasma membrane of 5‐HT neurons was, however, slightly higher in mouse than rat. Thus, in both rat and mouse DRN, a subpopulation of 5‐HT neurons is endowed with NK1r receptors and may be directly involved in the antidepressant‐like effects of NK1r antagonists. These 5‐HT neurons represent a new element in the neuronal circuitry currently proposed to account for the role of SP in mood regulation.
Status epilepticus differentially alters AMPA and kainate receptor subunit expression in mature and immature dentate granule neurons
Authors: Porter Brenda E. , Cui Xiao‐Nan , Brooks‐Kayal Amy R.
Published: June 2006

There is an increase in the birth of dentate granule neurons after status epilepticus (SE) and there are concurrent alterations in neurotransmitter receptor expression that may contribute to the development of spontaneous seizures. To determine whether newborn and/or mature dentate granule neurons have altered neurotransmitter receptor expression after SE, we dissected individual immature, PSA‐NCAM‐expressing, or mature, NeuN‐expressing, dentate granule neurons 2 weeks after lithium–pilocarpine‐induced SE in postnatal day 20 rats. Amplified single‐cell RNA was used to probe reverse Northern blots containing α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole propionic acid (AMPA) and kainate neurotransmitter receptor subunits. Two weeks after lithium–pilocarpine‐induced SE there were increases in AMPA GluR2 and kainate KA2 subunit mRNA and decreases in AMPA GluR3 and kainate GluR6 receptor subunit mRNA levels in mature dentate granule neurons. In contrast, only the kainate GluR6 subunit expression was reduced in immature dentate granule neurons after SE. Alterations in transcription of excitatory amino acid receptor subunits after SE occur primarily in the mature population of dentate granule neurons. Our findings suggest that neurotransmitter receptor gene expression is altered differently in immature and mature dentate granule neurons following SE, and may result in differential contributions of these two groups of dentate granule neurons to the subsequent development of epilepsy.
Factors affecting willow leaf beetles (Phratora vulgatissima) when selecting overwintering sites
Authors: Björkman Christer , Eklund Karin
Published: June 2006

Abstract 

Leaf beetles are major pests in willow plantations used as short‐rotation coppice for biomass production. The beetles overwinter mainly outside the plantations. An understanding of the factors affecting adult leaf beetles seeking overwintering sites may provide information that could be valuable when developing methods to control the beetles.

We conducted a field experiment in a willow plantation with a high abundance of the leaf beetle, Phratora vulgatissima. We positioned overwintering constructions (OWCs) made out of bundles of reed (Phragmites australis) outside the plantation.

Leaf beetles preferred (i) to fly towards silhouettes; (ii) OWCs positioned 1.5 m above the ground compared with ones 0.5 m above the ground; (iii) OWCs orientated vertically compared with OWCs orientated horizontally; and (iv) reeds of a diameter of approximately 5 mm.

Leaf beetle size was not correlated with reed diameter.

It is concluded that the leaf beetle P. vulgatissima selects an overwintering site based on factors at both larger and smaller scales. The possibilities for using OWCs made of reed bundles as tools to monitor and control are discussed.
Models for spring migration of two aphid species Sitobion avenae (F.) and Rhopalosiphum padi (L.) infesting cereals in areas where they are entirely holocyclic
Authors: Hansen Lars Monrad
Published: June 2006

1 Cereals can be attacked severely by the grain aphid, Sitobion avenae (F.), and the bird cherry‐oat aphid, Rhopalosiphum padi (L.). The time of migration from winter hosts in spring is important regarding input to decision support systems concerning insecticide treatment of aphids.

2 The present study aimed to construct two separate migration models, which could be used immediately for advisors and farmers but also be part of a decision support system for the chemical control of aphids in winter wheat and spring barley.

3 Winter wheat (Triticum sativum Lam.) and spring barley (Hordeum vulgare L.) fields were monitored from 1991–2005 for the occurrence of grain aphids and bird cherry‐oat aphids, and the data were used to construct migration models.

4 The models were constructed based on all 9 years data and subsequently validated by using all 9 years data, excluding 1 year at a time.

5 The migration model for the grain aphid producing the best forecast was obtained with migration date M (number of days from 1 June), degree‐days (DD) of April (Ta) and DD of May (Tm), with the model being M= 265.0 − 10.2 loge(Ta) − 35.1 loge(Tm).

6 The migration model for the bird cherry‐oat aphid producing the best forecast was obtained with migration date M (number of days from 15 May), DD of April (Ta) and DD from 1–15 May (Tm1), with the model being M= 294.4 − 34.7 loge(Ta) − 22.5 loge(Tm1).

7 The models only worked well in areas where the grain aphid and the bird cherry‐oat aphid are entirely holocyclic.
Distribution and population genetic structure of the Mediterranean pine shoot beetle Tomicus destruens in the Iberian Peninsula and Southern France
Authors: Vasconcelos Teresa , Horn Agnès , Lieutier François , Branco Manuela , Kerdelhué Carole
Published: June 2006

1 The Mediterranean pine shoot beetle Tomicus destruens has long been indistinguishable from its congeneric Tomicus piniperda. Both species attack pines, and can be found in sympatry. The geographical distribution of T. destruens is still unclear in most of the Mediterranean Basin.

2 We aimed to describe the geographical distribution and zones of sympatry of both species in the Iberian Peninsula and France, and to study the molecular phylogeographical pattern of T. destruens.

3 Tomicus spp. adults were sampled in Portugal, Spain and France, and a portion of the mitochondrial genes COI and COII was sequenced for 84 individuals. Sequences were aligned to a data set previously obtained from French localities.

4 Tomicus destruens was found in all populations, except for one locality in Portugal and in the Landes (France). It was in sympatry with T. piniperda in two locations on Pinus pinaster and one location on Pinus radiata.

5 Within‐population genetic diversity was high, but we found a significant pattern of spatial distribution of genetic variation, as well as a significant effect of the host tree.

6 The data suggest the existence of two glacial refugia, from which T. destruens recolonized its current range. One refugium was located in Portugal where the beetle probably evolved on P. pinaster. The corresponding haplotypes show a West–East frequency gradient. The other refugium was probably in the eastern range, where the beetles evolved on Pinus halepensis and P. pinea. The corresponding haplotypes show an East–West frequency gradient.
Phenology of Eucalyptus weevil, Gonipterus scutellatus Gyllenhal (Coleoptera: Curculionidae), and chrysomelid beetles in Eucalyptus globulus plantations in south‐western Australia
Authors: Loch A. D.
Published: June 2006

1 In south‐western Australia, Eucalyptus globulus plantations are defoliated by a complex of beetle species, yet only scant information exists on these species under such climatic conditions. To improve management of these defoliating beetles in the region, canopy fogging and shoot clipping were conducted in plantations between 1999 and 2002 to identify and document the phenology of the beetle species present.

2 Eucalyptus weevil, Gonipterus scutellatus, was the most common and destructive defoliating beetle. Gonipterus scutellatus undergoes one principal generation each year with a lesser second generation or cohort in some seasons, which contrasts greatly with reports of two to four annual generations for the species in other regions. This limited reproduction by G. scutellatus may be due to the limited availability from summer onwards of new flushing foliage, which is essential for feeding and oviposition.

3 Several species of chrysomelid beetles were collected in plantations, but these were present in much lower numbers than G. scutellatus and were only a minor concern. However, some species, such as Chrysophtharta variicollis, appear to be capable of developing short‐lived outbreaks.

4 A diverse suite of natural enemies was fogged from plantations but they were significantly less abundant than defoliating beetles and are not likely to provide significant control of beetles.

5 In terms of managing these defoliating beetles, monitoring and control should focus on G. scutellatus, and be conducted during spring when most damage occurs.
The role of chronic hypoxia in the development of neurocognitive abnormalities in preterm infants with bronchopulmonary dysplasia
Authors: Raman Lakshmi , Georgieff Michael K. , Rao Raghavendra
Published: June 2006

Bronchopulmonary dysplasia is the most common pulmonary morbidity in preterm infants and is associated with chronic hypoxia. Animal studies have demonstrated structural, neurochemical and functional alterations due to chronic hypoxia in the developing brain. Long‐term impairments in visual‐motor, gross and fine motor, articulation, reading, mathematics, spatial memory and attention skills are prevalent in survivors of bronchopulmonary dysplasia, and impairments appear to correlate with the severity of hypoxia. However, due to the simultaneous occurrence of multiple neurodevelopmental risk factors, a primary or potentiating role for chronic hypoxia in these impairments has yet to be conclusively established.
Factor Price Equalization in a World of Many Trading Countries
Authors: Kemp Murray C.
Published: June 2006

Conditions sufficient for factor price equalization within any non‐trivial subset of trading countries are provided. The conditions are that (a) the factor endowment ratios of countries in the subset are all bounded by the factors‐in‐use ratios in an equilibrium of the hypothetical world economy in which factors are perfectly mobile within the subset, and that (b) in dimensions higher than two, either the rank of the factors‐in‐use matrix is 2 or products do not outnumber factors and the factors‐in‐use matrix is of full rank.
Subcortical deficit pattern after brain abscess: a neuropsychological study
Authors: Visani P. , Schmutzhard E. , Trinka E. , Pfausler B. , Benke T.
Published: June 2006

The consequences of brain abscess (BA) on cognition and behaviour have never been examined in detail. The aim of this study was to determine the long‐term cognitive deficits of patients who suffered a BA and to estimate its effect on the quality of life. Twenty patients were included in the study. Follow up with neuropsychological and behavioural tests was performed 6 months to 42 years after BA (mean 10.4 ± 11.9). Cognitive deficits were defined as a test score of 2 or more standard deviations below controls’ mean in those tasks which revealed a significant group deficit. Compared with healthy age, sex and education‐matched controls, 13 of 20 patients (65%) exhibited neuropsychological deficits in some cognitive tasks. Ten of those patients (50%) were significantly impaired in ≤2 cognition domains, whilst the remaining three patients (15%) showed three to five impaired domains. No correlation was found between neuropsychological impairments and patients’ age, sex, initial neurological symptoms, size and localization of BA, or secondary epileptic seizures. Reduction in quality of life was found in five patients (25%). BA may cause long lasting cognitive deficits. Despite the focal character of the lesion, long‐term sequelae follow a more diffuse subcortical deficit pattern.
Child ADHD and personality/temperament traits of reactive and effortful control, resiliency, and emotionality
Authors: Martel Michelle M. , Nigg Joel T.
Published: June 2006

Background:  Models of attention‐deficit/hyperactivity disorder (ADHD) suggest developmental influences may feed into components of the disorder separately from associated disruptive behavior problems. We investigated this in terms of key personality/temperament traits of Reactive and Effortful Control, Resiliency, and Emotionality.

Methods:  A sample of 179 children (age 6–12, 63% boys), of whom 92 had ADHD, 52 were Controls, and 35 were borderline or not otherwise specified cases of ADHD, were examined. Dispositional trait scores were derived from parent‐completed California Q‐sort and the Early Adolescent Temperament Questionnaire. Child ADHD symptoms were evaluated using maternal structured diagnostic interview and teacher‐completed symptom ratings.

Results:  Traits were differentially associated with symptoms. Reactive Control was related to hyperactivity‐impulsivity as rated by both parents and teachers. Negative Emotionality was related to oppositional‐defiance. Resiliency was primarily related to inattention‐disorganization as rated by both parents and teachers; Effortful Control was related uniquely to inattention in parent but not teacher data. A moderation effect emerged; the relationship between parent‐rated Negative Emotionality and teacher‐rated ADHD symptoms was stronger for children with high levels of both Reactive and Effortful Control.

Conclusions:  Results are interpreted in relation to a two‐pathway model of ADHD; regulation problems contribute to the emergence of symptoms of inattention‐disorganization, reactive or motivational control problems to the emergence of hyperactivity‐impulsivity, and these are distinct from negative affectivity. Children with regulation deficits and a reactive motivational style are especially at risk for the development of ADHD.
HIV and reproductive care—a review of current practice
Authors: Gilling‐Smith C , Nicopoullos JDM , Semprini AE , Frodsham LCG
Published: June 2006

In developed countries, antiretroviral treatment has increased life quality and expectancy of HIV‐infected individuals and led to a drop in mother‐to‐child transmission (MCT) risk to below 1%. Fertility has been shown to be reduced in both men and women with HIV. As a result of these factors, the demand for reproductive care in this population is rising. In discordant couples where the man is positive, sperm washing significantly reduces viral transmission risk to the uninfected female partner over unprotected intercourse. Positive women do not necessarily need specialised fertility treatment but should be monitored closely during pregnancy to minimise MCT risk.
Identification of 10 microsatellite loci in the earwig Labidura riparia (Dermaptera, Labiduridae)
Authors: GUETH MAREIKE , DURKA WALTER
Published: June 2006

Ten microsatellite loci were isolated from the earwig Labidura riparia (Pallas, 1773). The polymorphism of the loci was assessed in 24 individuals from one population. The number of alleles ranged from four to 11 alleles and observed and expected heterozygosities from 0.250 to 0.833 and from 0.551 to 0.861, respectively.
Polymorphic microsatellite loci to study population dynamics in a dragonfly, the libellulid Trithemis arteriosa (Burmeister, 1839)
Authors: GIERE SANDRA , HADRYS HEIKE
Published: June 2006

One of the most widely distributed dragonfly species in Africa is the red‐veined‐dropwing Trithemis arteriosa. It is an indicator for permanent water bodies, which are freshwater ecosystems of high environmental value especially in arid regions. For studies to determine population structures, assess species viability and monitor environmental changes, a panel of 10 polymorphic microsatellite loci was developed. The number of alleles per locus ranged from four to 12, with an observed heterozygosity ranging from 0.149 to 0.843.
Impact of Alternative Interventions on Changes in Generic Dispensing Rates
Authors: O'Malley A. James , Frank Richard G. , Kaddis Atheer , Rothenberg Barbara M. , McNeil Barbara J.
Published: June 2006

Objectives. To evaluate the effectiveness of four alternative interventions (member mailings, advertising campaigns, free generic drug samples to physicians, and physician financial incentives) used by a major health insurer to encourage its members to switch to generic drugs.

Methods. Using claim‐level data from Blue Cross Blue Shield of Michigan, we evaluated the success of four interventions implemented during 2000–2003 designed to increase the use of generic drugs among its members. Around 13 million claims involving seven important classes of drugs were used to assess the effectiveness of the interventions. For each intervention a control group was developed that most closely resembled the corresponding intervention group. Logistic regression models with interaction effects between the treatment group (intervention versus control) and the status of the intervention (active versus not active) were used to evaluate if the interventions had an effect on the generic dispensing rate (GDR). Because the mail order pharmacy was considered more aggressive at converting prescriptions to generics, separate generic purchasing models were fitted to retail and mail order claims. In secondary analyses separate models were also fitted to claims involving a new condition and claims refilled for preexisting conditions.

Results. The interventions did not appear to increase the market penetration of generic drugs for either retail or mail order claims, or for claims involving new or preexisting conditions. In addition, we found that the ratio of copayments for brand name to generic drugs had a large positive effect on the GDR.

Conclusions. The interventions did not appear to directly influence the GDR. Financial incentives expressed to consumers through benefit designs have a large influence on their switching to generic drugs and on the less‐costly mail‐order mode of purchase.
Diagnostic Value of Flecainide Testing in Unmasking SCN5A‐Related Brugada Syndrome
Authors: MEREGALLI PAOLA G. , RUIJTER JAN M. , HOFMAN NYNKE , BEZZINA CONNIE R. , WILDE ARTHUR A.M. , TAN HANNO L.
Published: June 2006

Introduction: Provocation tests with sodium channel blockers are often required to unmask ECG abnormalities in Brugada syndrome (BrS). However, their diagnostic value is only partially established, while life‐threatening ventricular arrhythmias during these tests were reported. We aimed to establish sensitivity, specificity, and safety of flecainide testing, and to predict a positive test outcome from the baseline ECG.

Methods and Results: We performed 160 tests with flecainide in subjects determined to be at risk for BrS. P wave width, PQ duration, QRS width, S wave amplitude and duration in leads II‐III, in addition to ST morphology and J point elevation in V1‐V3 were measured before and after flecainide administration. Moreover, leads were positioned over the third intercostal space (V1IC3‐V2IC3). Flecainide tests were considered positive if criteria from the First Consensus Report on BrS were fulfilled. In 64 cases, the test was positive, while 95 were negative (1 test was prematurely interrupted). The sensitivity and specificity, calculated in SCN5A‐positive probands and their family members, were 77% and 80%, respectively. Baseline ECGs exhibited significant group differences in P, PQ, and QRS duration, J point elevation (leads V1‐V2 and V1IC3‐V2IC3), and S duration in II, but an attempt to predict the outcome of flecainide testing from these baseline ECG parameters failed. No malignant arrhythmias were observed.

Conclusion: Flecainide testing is a valid and safe tool to identify SCN5A‐related BrS patients. Baseline ECGs do not predict test outcomes, but point to conduction slowing as a core mechanism in BrS.
Retinoic acid synergistically enhances the melanocytotoxic and depigmenting effects of monobenzylether of hydroquinone in black guinea pig skin
Authors: Kasraee Behrooz , Fallahi Mohammad Reza , Ardekani Gholamreza Safaee , Ebrahimi Saeed , Doroudchi Gholamreza , Omrani Gholamhossein R. , Handjani Farhad , Amini Mitra , Tanideh Nader , Haddadi Marzieh , Nikbakhsh Mohammad , Jahanbani Saeedeh , Tran Christian , Sorg Olivier , Saurat Jean‐Hilaire
Published: June 2006

Abstract:  Monobenzylether of hydroquinone (MBEH) has long been utilized for the depigmentation therapy of patients with extensive vitiligo. In this approach, the normally pigmented areas surrounding vitiligo lesions are depigmented to achieve a uniform skin tone. One of the important disadvantages of MBEH therapy, however, is the resistance of a considerable number of vitiligo patients against the depigmenting effect of this agent. We have previously proposed that the glutathione‐dependent cytoprotection of melanocytes can be impaired through the inhibition of the enzyme glutathione S‐transferase by retinoic acid (RA). The combination of RA with melanocytotoxic agents could thus lead to increased susceptibility of melanocytes to such compounds. In this study we have shown, for the first time, that the melanocytotoxic and depigmenting effects of MBEH are synergistically enhanced when it is combined with RA. The treatment of black guinea pig skin with RA (0.025%) alone induced no significant changes in the number of epidermal melanocytes and no skin depigmentation. On the other hand, MBEH (10%) produced mild to moderate skin depigmentation and reduced the average number of melanocytes from 76 (±5)/field (magnification: × 40) in control sites, to 42 (±6)/field in the depigmented skin. The RA (0.025%)‐MBEH (10%) combination, however, produced a complete degree of depigmentation in the majority of treated sites after 10 days of application and reduced the average number of melanocytes to only 6 (±6)/field. RA‐MBEH combination serves as a very potent skin depigmenting formula and now awaits future assessments of its potential use for the treatment of extensive vitiligo.
Annual pattern of plasma melatonin and progesterone concentrations in hair and wool ewe lambs kept under natural photoperiod at lower latitudes in the southern hemisphere
Authors: Coelho L. A. , Rodrigues P. A. , Nonaka K. O. , Sasa A. , Balieiro J. C. C. , Vicente W. R. R. , Cipolla‐Neto J.
Published: June 2006

Abstract:   To study the annual pattern of plasma melatonin and progesterone concentrations in hair [Santa Inês (SI)] and wool [Romney Marsh (RM) and Suffolk (SU)] ewe lambs kept under natural photoperiods at 21°59′S, 12 ewe lambs (four/breed) were used. For melatonin, blood samples were collected monthly throughout the year at the onset (17:00, 19:00 and 21:00 hr) and end (04:00, 06:00 and 08:00 hr) of the night, and for progesterone the samples were collected in the morning, two to three times a week throughout the year. Plasma melatonin concentrations at different times of the day changed according to the season. In diurnal periods (17:00 and 8:00 hr) no seasonal differences were observed but they became evident in the nocturnal intervals (21:00 and 4:00 hr) and transitional night–day (6:00 hr) times. The patterns of melatonin secretion were higher in winter and autumn than in spring and summer. The patterns of plasma progesterone secretion were affected by interaction between breed and season. There was no seasonal variation in plasma progesterone concentrations for SI females. The progesterone pattern for RM and SU females varied with season. The plasma levels were higher in autumn and winter than in spring and summer. At 21°59′S hair and wool ewe lambs showed the same annual pattern of plasma melatonin concentration while the annual progesterone profiles were quite different. For SI females this pattern was constant along all seasons and for RM and SU females this pattern was higher during autumn and winter than spring and summer.
Melatonin reduces infarction volume in a photothrombotic stroke model in the wild‐type but not cyclooxygenase‐1‐gene knockout mice
Authors: Zou Liang Yu , Cheung Raymond Tak Fai , Liu Sirun , Li Geng , Huang Li
Published: June 2006

Abstract:  Cyclooxygenase (COX)‐2 plays a harmful role in cerebral ischemic/reperfusion injury, but the role of COX‐1 is uncertain. In the present study, cerebral infarct was induced by photothrombosis. Intraperitoneal injections of melatonin at 15 g/kg or its vehicle were made at 0.5 hr before stroke and 24 and 48 hr after stroke. Cerebral blood flow (CBF) in the penumbra was monitored during stroke using a laser Doppler flowmeter. Sensorimotor behavior was evaluated using the turning in an alley and falling from a pole tests at 1 hr before stroke and 24 and 48 hr after stroke. Infarct volume was determined from the T2‐weighted magnetic resonance images at 72 hr after stroke. During the first 15 min of stroke, CBF decreased in the penumbra in both homozygous COX‐1‐gene knockout and wild‐type mice. Melatonin treatment improved the penumbral CBF in the wild‐type mice. Mild poststroke impairment in sensorimotor behavior was detected by the turning in an alley test in which the COX‐1‐gene knockout mice performed better. Melatonin treatment did not affect the poststroke sensorimotor behavior. The relative infarct volume at 72 hr after stroke was 8.1% and 8.4% in the COX‐1‐gene knockout and wild‐type mice, respectively. Melatonin treatment reduced the relative infarct volume to 6.3% in the latter but not in the former (8.2%). Thus, COX‐1‐gene knockout does not affect the brain's susceptibility to photothrombotic stroke. Melatonin treatment reduces infarct size in the wild‐type mice following photothrombotic stroke partly via maintenance of penumbral CBF in which the COX‐1‐gene may play a role.
Is Concept‐Mapping an Effective Method of Introducing Complex Interventions into Intellectual Disability Services?
Authors: Sjoukes L. , Harteloh P. P. M. , Evenhuis H. M.
Published: June 2006

Abstract  As many adults with intellectual disability (ID) have an increased risk of low vision, ID service providers should play an active role in vision rehabilitation. However, low vision rehabilitation is a new and complex intervention for many providers in this field. To increase awareness of vision rehabilitation, it was proposed that the process of concept‐mapping be tested to see whether it would lead to increased acceptance of vision rehabilitation. In our test, the use of concept‐mapping appeared to be a satisfactory method for increasing awareness of professionals and middle managers of the complexity of vision rehabilitation, but it was found that it can only be useful for change if connected to a strategic decision by top management and the adoption of an action plan by the service provider.
Falls and Fractures: A Major Health Risk for Adults with Intellectual Disabilities in Residential Settings
Authors: Wagemans A. M. A. , Cluitmans J. J. M.
Published: June 2006

Abstract  Falls and fractures are a major health problem, especially among people with intellectual disabilities (ID). The authors report on an exploratory survey at one Dutch residential facility, aimed at determining the characteristics of people with ID who were prone to falling. Data on falls and fractures were compared with a number of characteristics of the institution’s residents. Each week data about falls were sampled during the study period of 33 months. It was found that risk factors for falling included: previous fractures, increasing age, impaired vision, seizures, use of antiepileptic drugs, and impaired mobility. Some 57% of the population fell during the observation period, resulting in 26 fractures. The authors noted that as the expected incidence of falling was high, an important finding was that people capable only of walking inside the building have a high risk of falling. The risk factors found can help identify those persons who are prone to falling, and this information can be used in fall prevention programs.
Masses and angular momenta of contact binary stars
Authors: Gazeas K. D. , Niarchos P. G.
Published: June 2006

Results are presented on component masses and system angular momenta for over 100 low-temperature contact binaries. It is found that the secondary components in close binary systems are very similar in mass. Our observational evidence strongly supports the argument that the evolutionary process goes from near-contact binaries to A-type contact binaries, without any need of mass loss from the system. Furthermore, the evolutionary direction of A-type into W-type systems with a simultaneous mass and angular momentum loss is also discussed. The opposite direction of evolution seems to be unlikely, since it requires an increase of the total mass and the angular momentum of the system.
Information content in the halo-model dark-matter power spectrum
Authors: Neyrinck Mark C. , Szapudi István , Rimes Christopher D.
Published: June 2006

Using the halo model, we investigate the cosmological Fisher information in the non-linear dark-matter power spectrum about the initial amplitude of linear power. We find that there is little information on ‘translinear’ scales (where the one- and two-halo terms are both significant) beyond what is on linear scales, but that additional information is present on small scales, where the one-halo term dominates. This behaviour agrees with the surprising results that Rimes & Hamilton found using N-body simulations. We argue that the translinear plateau in cumulative information arises largely from fluctuations in the numbers of large haloes in a finite volume. This implies that more information could be extracted on non-linear scales if the masses of the largest haloes in a survey are known.
Carotid baroreflex regulation of vascular resistance in high‐altitude Andean natives with and without chronic mountain sickness
Authors: Moore Jonathan P. , Claydon Victoria E. , Norcliffe Lucy J. , Rivera‐Ch Maria C. , Lèon‐Velarde Fabiola , Appenzeller Otto , Hainsworth Roger
Published: June 2006

We investigated carotid baroreflex control of vascular resistance in two groups of high‐altitude natives: healthy subjects (HA) and a group with chronic mountain sickness (CMS), a maladaptation condition characterized by high haematocrit values and symptoms attributable to chronic hypoxia. Eleven HA controls and 11 CMS patients underwent baroreflex testing, using the neck collar method in which the pressure distending the carotid baroreceptors was changed by applying pressures of −40 to +60 mmHg to the chamber. Responses of forearm vascular resistance were assessed from changes in the quotient of blood pressure divided by brachial artery blood velocity. Stimulus–response curves were defined at high altitude (4338 m) and within 1 day of descent to sea level. We applied a sigmoid function or third‐order polynomial to the curves and determined the maximal slope (equivalent to peak gain) and the corresponding carotid pressure (equivalent to ‘set point’). The results showed that the peak gains of the reflex were similar in both groups and at both locations. The ‘set point’ of the reflex, however, was significantly higher in the CMS patients compared to HA controls, indicating that the reflex operates over higher pressures in the patients (94.4 ± 3.0 versus 79.6 ± 4.1 mmHg; P < 0.01). This, however, was seen only when subjects were studied at altitude; after descent to sea level the curve reset to a lower pressure with no significant difference between HA and CMS subjects. These results indicate that carotid baroreceptor control of vascular resistance may be abnormal in CMS patients but that descent to sea level rapidly normalizes it. We speculate that this may be explained by CMS patients having greater vasoconstrictor activity at altitude owing to greater hypoxic stimulation of chemoreceptors.
NO
x

and N2O Emissions During Fluidized Bed Combustion of Leather Wastes
Authors: Bahillo Alberto , Armesto Lourdes , Cabanillas Andrés , Otero Juan
Published: June 2006

Transformation of hide (animal skins) into leather is a complicated process during which significant amounts of wastes are generated. Fluidized bed combustion has been extended to burn different wastes that have problems with their disposal showing its technical feasibility. Considering the characteristics of the leather waste, especially the heating value (12.5-21MJ∕kg), it is a fairly good fuel. Moreover, leather waste has a high volatile matter, 65%, similar to other biomasses and unusual high nitrogen content, 14%. The aim of this work was to study leather wastes combustion in fluidized bed presenting experimental results regarding NOx and N2O emissions. A series of experiments were carried out in a fluidized bed pilot plant to understand the importance of operating parameters such as furnace temperature, oxygen content in gases, staged combustion and residence time on the NOx and N2O emission level. Despite having high nitrogen content, low conversion of N-fuel to NOx and N2O was measured during the combustion of leather waste in BFB. Bed temperature and oxygen content were found as the most important single parameters on N2O emission and only oxygen content has a significant influence on NOx emission. Leather waste exhibits a great NOx∕O2 trend; NOx emission decreases as the oxygen concentration decreases while the effect of combustion temperature on NOx is insignificant. Staged combustion does not give a reduction in NOx.
Relation Between Stochastic Failure Location and Strength in Brittle Materials
Authors: Givli Sefi , Altus Eli
Published: June 2006

Statistical characteristics of failure location and their relation to strength in brittle materials are studied. One-dimensional rod and bending of a beam under arbitrary distributed loads are studied as examples. The analysis is based on the weakest link approach, and is not confined to specific strength distributions (such as Weibull, Gaussian, etc.). It is found that the statistical moments of the failure location (average, variance, etc.) are directly related to the area moments (centroid, inertia, etc.) of a simple function of the stress field. Therefore, important information related to material strength can be experimentally obtained based on measuring failure locations. Such experiments do not require the measurement of stresses, strains, or displacements, and are very attractive for MEMS/NEMS applications. The approach is general and can be applied to other types of testing specimens.
Continuum Damage Mechanics and the Life-Fraction Rule
Authors: Stigh U.
Published: June 2006

This paper gives a short review of two different methods for life prediction at high temperature; namely continuum damage mechanics (CDM) and the linear life-fraction rule (LFR). It is well known that the class of CDM theories with a separable evolution law gives a life prediction in accordance with the LFR. However, it appears to be an open question if this is a necessary condition. It is here shown that in order for a CDM theory to comply with the LFR it must have a separable evolution law. That is, if we can assume that a material follows the LFR, it is necessary to chose a separable evolution law for this material. The reverse is also true, to get a life-fraction different from unity, we must chose a nonseparable evolution law.
Reconfiguration of a Rolling Sphere: A Problem in Evolute-Involute Geometry
Authors: Das Tuhin , Mukherjee Ranjan
Published: June 2006

This paper provides a new perspective to the problem of reconfiguration of a rolling sphere. It is shown that the motion of a rolling sphere can be characterized by evolute-involute geometry. This characterization, which is a manifestation of our specific selection of Euler angle coordinates and choice of angular velocities in a rotating coordinate frame, allows us to recast the three-dimensional kinematics problem as a problem in planar geometry. This, in turn, allows a variety of optimization problems to be defined and admits infinite solution trajectories. It is shown that logarithmic spirals form a class of solution trajectories and they result in exponential convergence of the configuration variables.
Ultrasonic Field Modeling in Multilayered Fluid Structures Using the Distributed Point Source Method Technique
Authors: Banerjee Sourav , Kundu Tribikram , Placko Dominique
Published: June 2006

In the field of nondestructive evaluation (NDE), the newly developed distributed point source method (DPSM) is gradually gaining popularity. DPSM is a semi-analytical technique used to calculate the ultrasonic field (pressure and velocity fields) generated by ultrasonic transducers. This technique is extended in this paper to model the ultrasonic field generated in multilayered nonhomogeneous fluid systems when the ultrasonic transducers are placed on both sides of the layered fluid structure. Two different cases have been analyzed. In the first case, three layers of nonhomogeneous fluids constitute the problem geometry; the higher density fluid is sandwiched between two identical fluid half-spaces. In the second case, four layers of nonhomogeneous fluids have been considered with the fluid density monotonically increasing from the bottom to the top layer. In both cases, analyses have been carried out for two different frequencies of excitation with various orientations of the transducers. As expected, the results show that the ultrasonic field is very sensitive to the fluid properties, the orientation of the fluid layers, and the frequency of excitation. The interaction effect between the transducers is also visible in the computed results. In the pictorial view of the resulting ultrasonic field, the interface between two fluid layers can easily be seen.
Rapid Thermal Characterization of the High Thermal Conductivity Film Layers by the Film-on Substrate Technique
Authors: Sadeghipour Sadegh M. , Asheghi Mehdi
Published: June 2006

Lack of an efficient thermal management strategy and system can often lead to overall system failure in advanced microprocessors. This can be avoided by utilization of the high thermal conductivity materials, as heat spreader/sink, in compact packaging systems. The diamondlike dielectric materials, such as diamond, silicon nitride (Si3N4), aluminum nitride (AlN), silicon carbide (SiC), etc., are the likely choices. However, thermal characterization of such high thermal conductivity materials has proven to be challenging due to variations in the fabrication processes and, therefore, their microstructures as well as the practical difficulties in measuring small temperature gradients during the characterization. In this paper, we will report on a novel film on substrate technique that can be used conveniently for repeated measurements of the lateral thermal conductivity of the high thermal conductivity film layers, with thicknesses between 100 and 500μm.
Nanoscale Thermal Phenomena in Tunnel Junctions for Spintronics Applications
Authors: Ju Yongho “Sungtaek”
Published: June 2006

The nascent field of spintronics has great potential to enable new types of information processing and storage devices and supplement conventional semiconductor electronics. An overview of nanoscale thermal phenomena in a tunnel junctions is provided, which is one of the key building blocks of spintronic devices. Experiments showed that the thermal resistance of nanoscale AlOx tunnel barriers increases linearly with thickness, which is consistent with the theory of energy transport in highly disordered materials. Heat conduction across a tunnel junction is impeded by significant additional resistance at interfaces between the barrier layer and electrodes due to mismatch in atomic vibrational properties and nonequilibrium between electrons and phonons. The quantum-mechanical tunneling probability depends strongly on electron energy, which leads to asymmetry in heat-generation rate along the two opposing electrodes of a tunnel junction.
On the Crashworthiness
of Shear-Rigid Sandwich Structures
Authors: Mohr Dirk , Wierzbicki Tomasz
Published: June 2006

This paper deals with the evaluation of the crashworthiness of thin-walled sandwich box structures for automotive applications. Quasi-static crushing simulations are carried out to estimate the energy absorption of prismatic box columns made from sandwich sheets. The sandwich sheets have perforated cores of different densities with staggered holes perpendicular to the panel faces. It is found that the specific energy absorption of columns made of sandwich sheets is approximately the same as that of conventional columns composed of homogeneous sheets of the same total wall thickness. Furthermore, theoretical analysis indicates that by increasing the core thickness, sandwich structures could be up to 50% lighter while providing the same mean crushing force. However, these gains may not be achieved in practical applications since increasing the core thickness also increases the likelihood of premature face sheet fracture during crushing.
Thermal Phenomena in Nanoscale Transistors
Authors: Pop Eric , Goodson Kenneth E.
Published: June 2006

As CMOS transistor gate lengths are scaled below 45nm, thermal device design is becoming an important part of microprocessor engineering. Decreasing dimensions lead to nanometer-scale hot spots in the drain region of the device, which may increase the drain series and source injection electrical resistances. Such trends are accelerated with the introduction of novel materials and nontraditional transistor geometries, like ultrathin body, surround-gate, or nanowire devices, which impede heat conduction. Thermal analysis is complicated by subcontinuum phenomenan including ballistic electron transport, which reshapes the hot spot region compared with classical diffusion theory predictions. Ballistic phonon transport from the hot spot and between material boundaries impedes conduction cooling. The increased surface to volume ratio of novel transistor designs also leads to a larger contribution from material boundary thermal resistance. In this paper we survey trends in transistor geometries and materials, from bulk silicon to carbon nanotubes, along with their implications for the thermal design of electronic systems.
“Heat Shield”—An Enhancement Device for an Unshrouded, Forced Convection Heat Sink
Authors: Prstic Suzana , Bar-Cohen Avram
Published: June 2006

The inherent advantages of forced air cooling have led to the widespread use of fully and partially shrouded heat sinks for the thermal management of high power microprocessors. The superior thermal performance that is achievable in the fully shrouded configuration is accompanied by a significant pressure drop penalty. The concept introduced in the current study, employs a thin sheet-metal “heat shield,” placed around a partially shrouded heat sink, to channel the flow directly into the heat sink. A combined numerical and experimental study has shown that the use of this “heat shield” can substantially enhance heat sink thermal performance, in a channel geometry and air flow range typical of commercial chip packages; making it comparable to that of a fully shrouded heat sink, with a substantially lower pressure drop (∼50%). In addition, this thermal enhancement device can be easily retrofitted into existing systems; improving performance without major channel and/or fan modifications.