bluuebunny/crossref_metadata_2025 huggingface dataset:
Traction Motor Experience on Toronto Subway
Authors: Jowett W G
Published: October 2007

The paper gives a brief history of the Toronto Subway and how a British company became involved in the supply of prototype traction motors to the Toronto Transit Commission (TTC) followed in 1971 by the supply of motors for the H2 stock. On the test bed these motors were shown to be up to specification with reasonable margins on rating and commutation, but after varying periods in service, problems arose which were dealt with and overcome effectively except for one problem connected with commutator face erosion, which became known as the TIR problem'2, the cause of which proved to be most elusive. The main content of the paper concerns the search for the cause and a solution to this problem.

In 1973, TTC called for tenders for further subwaycars (the H4 stock). At this stage, causes and solutions to the TIR problem had been suggested and interim results were promising. However, after negotiating special guarantees, eventually an order was received for H4 stock motors which incorporated improvements and the suggested remedies to the ‘TIR problem’.

These motors have now satisfactorily completed over 400 000 miles in service showing that the solutions applied were sound and effective and it is now estimated that the period between commutator skimming will be 500 000 miles or over.
The Testing and Approval of Aircraft Engine Mounted Accessories
Authors: Pearson D S
Published: October 2007

Vibration measurements on gas turbine engines are normally made using accelerometers. The environment to which engine accessories would be subject has been evaluated by comparing ‘g’ peaks in the frequency spectrum, individually, with empirical yardsticks of severity. Endurance approval testing of accessories to withstand the environment so characterized is normally conducted by applying unidirectional single frequency excitation to simulate engine conditions at a particular shaft speed. These procedures have proved inadequate in predicting failure or verifying corrective measures where accessory problems due to wear phenomena are concerned.

This paper analyses reasons for this inadequacy in terms of measurement practice, engine severity assessment, environmental simulation and approval procedures. By recognizing the effect of multi-frequency vibration in three planes it further aims to provide a unified approach to accessory design and development by which service accessory reliability might be improved. Although at first sight more expensive, the approach described will in many cases reduce to previous practice. In cases where greater test expenditure is necessary, loopholes will have been plugged by which many expensive service problems previously escaped.
The Stressing for Test Purposes of Materials in Tubular Form Using Elastomeric Inserts—Experimental and Theoretical Development
Authors: Mosley K
Published: October 2007

This paper describes the theoretical and practical aspects of a simple and rapid method of elastically hoop stressing materials in tubular form using elastomeric inserts. The method can be used for stressing to required limits, for testing to fracture or for obtaining yield points. It is extremely suitable for the testing of brittle materials. Stress equations and insert/test specimen coefficients of friction are given in appendices.
Noise Control in the Design of Process Plants
Authors: Erskine J B
Published: October 2007

The design of process plant must incorporate noise control since retro-fitting is impractical on both technical and economic grounds. Whilst the method of approach depends on particular circumstances, key factors common to all projects are: setting of realistic specifications; establishing working procedures which ensure full co-operation by all members of the design team; early identification of the most difficult problems so that the most economic solutions can be generated; utilization of good and bad experience from previous projects to minimize noise control costs, this forms the basic work load in most projects; evaluation of the completed plant so that the degrees of success can be determined and lessons can be learned for future projects.

These, and some technical aspects, are covered in the paper and whilst they are based on experience with large process plants they are equally applicable to smaller plants. The need for ‘in house’ knowhow is essential to the whole exercise since the noise sources are a function of the process and much of the data is of an empirical and practical nature.
‘Things can only get Better’: expectations and the welfare state
Authors: Taylor-Gooby Peter
Published: October 2007

English

An influential recent study argues that disenchantment with the achievements of the welfare state results from the comparison between modest welfare performance and the improvements in standards of provision in the non-state sector associated with rising living standards (Glennerster and Hills, 1998). This article analyses recent data from the British Social Attitudes survey to show that dissatisfaction in the flagship area of the National Health Service is associated with underprivilege rather than secure and rising standards of living. The implication is that the traditional defence of state welfare, as providing for those who experience needs which they find difficult to satisfy through the market, may still strike a chord with public opinion.
The Judiciary in the 1990s: guardian of the welfare state?
Authors: Woodhouse Diana
Published: October 2007

English

During the 1990s there have been indications that a number of senior judges are concerned to protect and preserve the principles upon which the UK welfare state is based. In addition, they see a correlation between welfare provisions and fundamental human rights and, in some instances, view a withdrawal of these provisions as an infringement of human rights. This article examines judicial attitudes in cases which have raised benefit, health and education issues and suggests that the incorporation of the European Convention on Human Rights may have the effect of increasing the role of the judiciary as guardian of the welfare state.
Structure and dynamics of levitated liquid materials
Authors: Hennet Louis , Krishnan Shankar , Pozdnyakova Irina , Cristiglio Viviana , Cuello Gabriel J. , Fischer Henry E. , Bytchkov Aleksei , Albergamo Francesco , Zanghi Didier , Brun Jean-François , Brassamin Séverine , Saboungi Marie-Louise , Price David L.
Published: October 2007

Aerodynamic levitation is a simple way to suspend samples which can be heated with CO2lasers. The advantages of this technique are the simplicity and compactness of the device, making it possible to integrate the device easily into different kinds of experiments. In addition, all types of sample can be used, including metals and oxides. The integration of this technique at synchrotron and neutron sources provides powerful tools to study molten materials.
Osteoblasts Express NLRP3, a Nucleotide-Binding Domain and Leucine-Rich Repeat Region Containing Receptor Implicated in Bacterially Induced Cell Death
Authors: McCall Samuel H , Sahraei Mahnaz , Young Amy B , Worley Charles S , Duncan Joseph A , Ting Jenny Pan-Yun , Marriott Ian
Published: October 2007

Bacterially induced osteoblast apoptosis may be a major contributor to bone loss during osteomyelitis. We provide evidence for the functional expression in osteoblasts of NLRP3, a member of the NLR family of cytosolic receptors that has been implicated in the initiation of programmed cell death.

Introduction: Osteoblasts undergo apoptosis after exposure to intracellular bacterial pathogens commonly associated with osteomyelitis. Death of this bone-forming cell type, in conjunction with increased numbers and activity of osteoclasts, may underlie the destruction of bone tissue at sites of bacterial infection. To date, the mechanisms responsible for bacterially induced apoptotic osteoblast cell death have not been resolved.

Materials and Methods: We used flow cytometric techniques to determine whether intracellular invasion is needed for maximal apoptotic cell death in primary osteoblasts after challenge with Salmonella enterica. In addition, we used real-time PCR and immunoblot analyses to assess osteoblast expression of members of the nucleotide-binding domain leucine-rich repeat region-containing family of intracellular receptors (NLRs) that have been predicted to be involved in the induction of programmed cell death. Furthermore, we have used co-immunoprecipitation and siRNA techniques to confirm the functionality of such sensors in this cell type.

Results: In this study, we showed that invasion of osteoblasts by Salmonella is necessary for maximal induction of apoptosis. We showed that murine and human osteoblasts express NLRP3 (previously known as CIAS1, cryopyrin, PYPAF1, or NALP3) but not NLRC4 (IPAF) and showed that the level of expression of this cytosolic receptor is modulated after bacterial challenge. We showed that osteoblasts express ASC, an adaptor molecule for NLRP3, and that these molecules associate after Salmonella infection. In addition, we showed that a reduction in the expression of NLRP3 attenuates Salmonella-induced reductions in the activity of an anti-apoptotic transcription factor in osteoblasts. Furthermore, we showed that NLRP3 expression is needed for caspase-1 activation and maximal induction of apoptosis in osteoblasts after infection with Salmonella.

Conclusions: The functional expression of NLRP3 in osteoblasts provides a potential mechanism underlying apoptotic cell death of this cell type after challenge with intracellular bacterial pathogens and may be a significant contributory factor to bone loss at sites of infection.
Serum 25-Hydroxyvitamin D and Hip Fracture Risk in Older U.S. White Adults
Authors: Looker Anne C , Mussolino Michael E
Published: October 2007

We used serum 25(OH)D data from NHANES III and incident hip fracture cases identified using linked mortality and Medicare records, and found that serum 25(OH)D was significantly related to reduced hip fracture risk in non-Hispanic white adults ≥65 yr of age.

Introduction: The role of vitamin D status in reducing fracture risk is unclear. We examined the relationship between serum 25 hydroxyvitamin D [25(OH)D] and incident hip fracture risk in older non-Hispanic white adults.

Materials and Methods: The study sample consisted of 1917 white men and women ≥65 yr of age who were examined in the third National Health and Nutrition Examination Survey (NHANES III, 1988-1994), a nationally representative survey. Incident hip fractures were ascertained using linked mortality and Medicare records that were obtained for NHANES III participants. Serum 25(OH)D values were measured with a radioimmunoassay kit. Cox proportional hazards models were used to estimate the relative risk (RR) of hip fracture by serum 25(OH)D level.

Results: There were 156 incident hip fracture cases in the sample. Cases were older, had lower BMD and body mass index, more prevalent spine or wrist fractures and weight loss before baseline, and ate fewer kilocalories and less calcium than noncases. After adjusting for these differences, serum 25(OH)D values exceeding 60 nM were significantly related to hip fracture risk. For example, the multivariate-adjusted RR was 0.64 (95% CI, 0.46-0.89) among individuals with serum 25(OH)D values ≥62.5 nM compared with those with values below this level. When grouped into quartiles, the multivariate-adjusted RR for the second, third, and fourth versus the first quartile of serum 25(OH)D were 0.50 (95% CI, 0.25-1.00), 0.41 (95% CI, 0.24-0.70), and 0.50 (95% CI, 0.29-0.86), respectively.

Conclusions: Serum 25(OH)D was related to a significantly lower hip fracture risk in this cohort of older white adults, even after adjusting for several relevant confounding variables. The relationship did not seem to be linear across all values. Our results support other studies suggesting that serum 25(OH)D values exceeding 60 nM are associated with health benefits.
Assessing Population Risk for Postmenopausal Osteoporosis: A New Strategy Using Data From the Behavioral Risk Factor Surveillance System (BRFSS)
Authors: Schneyer Christine R , Lopez Helio , Concannon Mary , Hochberg Marc C
Published: October 2007

Osteoporosis public health measures are hindered by the inability to easily identify subclinical disease. We have now estimated state-specific osteoporosis prevalences using a simple formula (OST Index) to analyze age and weight of 62,882 older women; the prevalences determined are similar to those based on BMD. This new method has potential use for guiding implementation of osteoporosis prevention/treatment programs.

Introduction: Although osteoporosis-related fractures are a major U.S. public health issue, population-based prevention programs have not yet been developed. One contributing factor has been lack of a suitable screening test to detect asymptomatic high-risk individuals.

Materials and Methods: We estimated state-specific prevalences of postmenopausal osteoporosis using the Osteoporosis Self-Assessment Tool Index (OST Index; [self-reported weight in kg - age] × 0.2) to analyze data from 62,882 women ≥50 yr of age who participated in the 2002 Behavioral Risk Factor Surveillance System (BRFSS). The OST Index, designed to assess an individual's risk of disease, has previously been shown to have modest positive and high negative predictive value for osteoporosis defined by BMD criteria. Based on this index, women from each state were distributed among high-, moderate-, and low-risk OST categories. Calculated percentages for each category were weighted to U.S. Census Bureau population projections for 2002. By adjusting results to reflect previously validated percentages of women with osteoporosis in each risk category, we estimated the prevalence of postmenopausal osteoporosis in each state.

Results: Our calculated weighted prevalence estimates agreed closely with those of the National Osteoporosis Foundation derived from actual femoral neck BMD measurements obtained in the third National Health and Nutrition Examination Survey (1988-1994) and projected to U.S. census state population predictions for 2002. Comparison of unweighted BRFSS-OST results and NHANES BMD data revealed similar percentages of osteoporosis among all women ≥50 yr of age (BRFSS, 18.5%; NHANES, 18.0%; p = 0.47) and also among white women (BRFSS, 19.0%; NHANES, 20.0%; p = 0.28). However, the percentages of osteoporosis among blacks and Hispanics did not correspond, at least partly because of the lack of race-specific reference standards for BMD measurements and OST index ranges.

Conclusions: Analysis of readily available BRFSS data with the OST index formula is a simple, no-cost technique that provides state prevalence estimates of postmenopausal osteoporosis that could be used to guide allocation of resources to statewide osteoporosis prevention programs.
The Association between Life Events and Suicide Intent in Self‐Poisoners with and without a History of Deliberate Self‐Harm: A Preliminary Study
Authors: Crane Catherine , Williams J. Mark. G. , Hawton Keith , Arensman Ella , Hjelmeland Heidi , Bille‐Brahe Unni , Corcoran Paul , De Leo Diego , Fekete Sandor , Grad Onja , Haring Christian , Kerkhof Ad J.F.M. , Lonnqvist Jouko , Michel Konrad , Renberg Ellinor Salander , Schmidtke Armin , van Heeringen Cornelius , Wasserman Danuta
Published: September 2007

The associations between life events in the 12 months preceding an episode of self‐poisoning resulting in hospital attendance (the index episode), and the suicide intent of this episode were compared in individuals for whom the index episode was their first, episode and in individuals in whom it was a recurrence of DSH. Results indicated a significant interaction between independent life events, repetition status, and gender in the prediction of suicide intent, the association between life events and intent being moderated by repetition status in women only. The results provide preliminary evidence to suggest the presence of a suicidal process in women, in which the impact of negative life events on suicide intent diminishes across episodes.
Motives and Suicide Intent Underlying Hospital Treated Deliberate Self‐Harm and Their Association with Repetition
Authors: McAuliffe Carmel , Arensman Ella , Keeley Helen S. , Corcoran Paul , Fitzgerald Anthony P.
Published: September 2007

The association between motives for deliberate self‐harm (DSH), level of suicide intent, and history of DSH is poorly understood. As part of the WHO/EURO Multicentre Study on Suicidal Behavior, the Suicide Intent Scale, and the Motives for Parasuicide Questionnaire were administered to 146 patients presenting with DSH in the Cork region in Ireland. DSH patients reporting high suicide intent were more motivated to escape from their problem (M = 3.15, p < .001) compared to those with low suicide intent, who were more motivated to appeal to others (M = 1.61, p < .001) and to get a temporary break from their problem (M = 2.47, p < .001). Repeaters more often reported motives aimed at escape (M = 2.98, p < .01), revenge (M = .60, p < .005), and appeal (M = 1.43, p = <.05). Self‐harming patients are characterized by ambivalence and struggle with aversive thoughts and situations. Therapeutic approaches should include distress management and coping strategies.
Risk Factors Associated with Suicide Attempts and Other Self‐injury Among Hong Kong Adolescents
Authors: Wong Joy P. S. , Stewart Sunita M. , Ho S. Y. , Lam T. H.
Published: September 2007

This study examined 1,361 Chinese adolescents who reported self‐injurious behaviors. Groups A and B both acknowledged deliberate self‐injury, but only Group A had made a suicide attempt. Group C reported accidental self‐injury. Deliberate self‐injurers (Groups A and B) were more frequently girls, older, and with more suicidal ideation. Group A had more psychopathology, environmental and suicide‐related risk factors than group B and C. Group C had higher depressive symptoms than noninjured controls. The study clarifies differences among self‐injurious behavior groups based on expressed deliberate self‐injury and self‐reported suicide attempt. These three groups appear to present a continuum of risk.
Childhood Physical and Sexual Abuse in Depressed Patients with Single and Multiple Suicide Attempts
Authors: Andover Margaret S. , Zlotnick Caron , Miller Ivan W.
Published: September 2007

Research has shown both childhood physical and sexual abuse to be associated with later suicide attempts, although some studies have not supported these findings. However, few studies have investigated differences in physical and sexual abuse histories among single and multiple suicide attempters. The goals of the current study were two‐fold: (a) to replicate previous findings of associations between childhood sexual and physical abuse and suicide attempts, and (b) to explore differences in reports of childhood physical and sexual abuse among single and multiple suicide attempters. While our results supported the findings that individuals with a history of suicide attempts are more likely to report histories of childhood physical and sexual abuse, we did not find a difference in reported abuse between single and multiple suicide attempters. Implications of these findings, as well as implications for future research, are discussed.
Postsynaptic Secretion of BDNF and NT-3 from Hippocampal Neurons Depends on Calcium–Calmodulin Kinase II Signaling and Proceeds via Delayed Fusion Pore Opening
Authors: Kolarow Richard , Brigadski Tanja , Lessmann Volkmar
Published: September 2007

The mammalian neurotrophins (NTs) NGF, BDNF, NT-3, and NT-4 constitute a family of secreted neuronal growth factors. In addition, NTs are implicated in several forms of activity-dependent synaptic plasticity. Although synaptic secretion of NTs has been described, the intracellular signaling cascades that regulate synaptic secretion of NTs are far from being understood. Analysis of NT secretion at the subcellular level is thus required to resolve the role of presynaptic and postsynaptic NT secretion for synaptic plasticity. Here, we transfected cultures of dissociated rat hippocampal neurons with green fluorescent protein-tagged versions of BDNF and NT-3, respectively, and identified NT vesicles at glutamatergic synapses by colocalization with the cotransfected postsynaptic marker PSD-95 (postsynaptic density-95)-DsRed. Depolarization-induced secretion of BDNF and NT-3 was monitored with live cell imaging. Direct postsynaptic depolarization with elevated K+in the presence of blockers of synaptic transmission allowed us to investigate the signaling cascades that are involved in the postsynaptic NT vesicle secretion process. We show that depolarization-induced postsynaptic NT secretion is elicited by Ca2+influx, either via L-type voltage-gated calcium channels or via NMDA receptors. Subsequent release of Ca2+from internal stores via ryanodine receptors is required for the secretion process. Postsynaptic NT secretion is inhibited in the presence of KN-62 ([4(2S)-2-[(5-isoquinolinylsulfonyl)methylamino]-3-oxo-3-(4-phenyl-1-piperazinyl)propyl] phenyl isoquinolinesulfonic acid ester) and KN-93 (N-[2-[[[3-(4-chlorophenyl)-2-propenyl]methylamino]methyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide), indicating a critical dependence on the activation of α-calcium–calmodulin-dependent protein kinase II (CaMKII). The cAMP/protein kinase A (PKA) signaling inhibitor Rp-cAMP-S impaired NT secretion, whereas elevation of intracellular cAMP levels was without effect. Using the Trk inhibitor k252a, we show that NT-induced NT secretion does not contribute to the NT release process at synapses, and BDNF does not induce its own secretion at postsynaptic sites. Release experiments in the presence of the fluorescence quencher bromphenol blue provide evidence for asynchronous and prolonged fusion pore opening of NT vesicles during secretion. Because fusion pore opening is fast compared with compound release, the speed of NT release seems to be limited by diffusion of NTs out of the vesicle. Together, our results reveal a strong dependence of activity-dependent postsynaptic NT secretion on Ca2+influx, Ca2+release from internal stores, activation of CaMKII, and intact PKA signaling, whereas Trk signaling and activation of Na+channels is not required.
Stimulus Feature Selectivity in Excitatory and Inhibitory Neurons in Primary Visual Cortex
Authors: Cardin Jessica A. , Palmer Larry A. , Contreras Diego
Published: September 2007

Although several lines of evidence suggest that stimulus selectivity in somatosensory and visual cortices is critically dependent on unselective inhibition, particularly in the thalamorecipient layer 4, no comprehensive comparison of the responses of excitatory and inhibitory cells has been conducted. Here, we recorded intracellularly from a large population of regular spiking (RS; presumed excitatory) and fast spiking (FS; presumed inhibitory) cells in layers 2–6 of primary visual cortex. In layer 4, where selectivity for orientation and spatial frequency first emerges, we found no untuned FS cells. Instead, the tuning of the spike output of layer 4 FS cells was significantly but moderately broader than that of RS cells. However, the tuning of the underlying synaptic responses was not different, indicating that the difference in spike-output selectivity resulted from differences in the transformation of synaptic input into firing rate. Layer 4 FS cells exhibited significantly lower input resistance and faster time constants than layer 4 RS cells, leading to larger and faster membrane potential (Vm) fluctuations. FS cellVmfluctuations were more broadly tuned than those of RS cells and matched spike-output tuning, suggesting that the broader spike tuning of these cells was driven by visually evoked synaptic noise. These differences were not observed outside of layer 4. Thus, cell type-specific differences in stimulus feature selectivity at the first level of cortical sensory processing may arise as a result of distinct biophysical properties that determine the dynamics of synaptic integration.
Transient Growth Factor Delivery Sustains Regenerated Axons after Spinal Cord Injury
Authors: Blesch Armin , Tuszynski Mark H.
Published: September 2007

Growth factors influence the topography of axonal projections during nervous system development and facilitate axonal sprouting and regeneration after injury in the adult. However, in the absence of target reinnervation and reestablishment of synaptic activity, we hypothesized that continuing delivery of neurotrophins would be required to sustain regenerating axons for prolonged times points after neurotrophin-induced axon growth after spinal cord injury (SCI) in the adult. Using tetracycline-inducible expression of brain-derived neurotrophic factor by genetically modified fibroblasts, we were able to extensively and significantly turn growth factor expression “on” or “off”in vitroandin vivowithin sites of SCI. Notably, we find that transient growth factor delivery is sufficient to sustain regenerated axons for prolonged time periods within spinal cord lesion sites. Immunohistochemical analysis demonstrated an absence of neuronal targets or synapses within transient growth factor expressing grafts but the persistent presence of Schwann cells. Thus, the adult CNS appears capable of sustaining axons that have extended after transient growth factor delivery, an effect potentially attributable to the persistence of Schwann cells in lesion/graft sites.
Critical Roles for the M3–S2 Transduction Linker Domain in Kainate Receptor Assembly and Postassembly Trafficking
Authors: Vivithanaporn Pornpun , Lash Laura Leanne , Marszalec William , Swanson Geoffrey T.
Published: September 2007

Kainate receptors (KARs) are neuronal proteins that exhibit a highly polarized distribution in the mammalian CNS. Assembly, intracellular trafficking, and synaptic targeting of KARs and other ionotropic glutamate receptors are processes controlled, in part, by various determinants within the constituent subunit proteins themselves. Here, we demonstrate that the linker region between the M3 and S2 domains, which in current structural models is thought to transduce ligand-binding energy into channel opening, additionally has an essential role in receptor biogenesis. Our results show that this gating-associated domain is engaged at two distinct critical stages of KAR biogenesis: first, during the transition from dimeric to tetrameric assembly states and, second, at a postassembly trafficking checkpoint within the endoplasmic reticulum. Alteration of a basic residue, arginine 663, altered the desensitization properties of the GluR6 kainate receptor in response to glutamate application, and these changes were weakly correlated with intracellular retention of the mutant receptors. Elimination of the positive charge also significantly attenuated oligomerization and stability of the intracellular subunit protein. Furthermore, charge swapping with an adjacent residue, glutamate 662, normalized the receptor physiological behavior and reversed the deficits in assembly and degradation, but only partially restored plasma membrane expression of the receptors. These results reveal a new role for this linker domain in glutamate receptor biogenesis and contribute to understanding the cellular controls of receptor assembly and trafficking, which will be important for relating receptor stoichiometry to their neuronal targeting and function.
Diffusion Tensor Magnetic Resonance Imaging and Tract-Tracing Analysis of Probst Bundle Structure in Netrin1- and DCC-Deficient Mice
Authors: Ren Tianbo , Zhang Jiangyang , Plachez Celine , Mori Susumu , Richards Linda J.
Published: September 2007

In many cases of callosal dysgenesis in both human patients and mouse models, misguided fibers from the cortex form abnormal bilateral, barrel-shaped structures known as Probst bundles. Because little is known about how axons are arranged within these anomalous fiber bundles, understanding this arrangement may provide structural and molecular insights into how axons behave when they are misguidedin vivo. Previous studies described these bundles as longitudinal swirls of axons that fail to cross the midline (Ozaki et al., 1987). However, recent studies on human acallosal patients using diffusion tensor magnetic resonance imaging (DTMRI) technology suggest that axons project in an anteroposterior direction within the Probst bundle (Lee et al., 2004; Tovar-Moll et al., 2007). This led us to ask the question, is DTMRI an accurate method for analyzing axonal tracts in regions of high axon overlap and disorganization, or is our current perception of axon arrangement within these bundles inaccurate? Using DTMRI, immunohistochemistry, and carbocyanine dye tract-tracing studies, we analyzed the Probst bundles in both Netrin1 and deleted in colorectal cancer (DCC) mutant mice. Our findings indicate that DTMRI can accurately demonstrate fiber tract orientation and morphology where axons are in ordered arrays such as in the dorsal part of the bundle. In ventral areas, where the axons are disorganized, no coordinated diffusion is apparent via DTMRI. In these regions, a higher-resolution approach such as tract tracing is required. We conclude that in DCC and Netrin1 mutant mice, guidance mechanisms remain in the dorsal part of the tract but are lost ventrally.
Three-dimensional/Four-dimensional Ultrasonography to Detect Fetal Brain Damage
Authors: Amiel-Tison Claudine , Gosselin Julie , Kurjak Asim
Published: October 2007

Understanding the pattern of maturation of the fetal brain sets the stage for ultrasonographic documentation of neural development or damage. General movements and primary reflexes are the expression of spinal motor activity in the first half of pregnancy, but increasingly complex functions denote the switch over from initial spinal control to a higher control in the second half of the pregnancy. Both the Prechtl Neurologic Assessment and the Amiel-Tison Neurologic Assessment at Term have been used as the basis for proposed three- and four-dimensional ultrasonographic criteria of central nervous system optimality and fetal central nervous system compromise. The predictive value of such imaging is limited by its “hands-off” observation and the immaturity of the fetal brain, but the possibility of employing such advanced imaging holds great promise.
Effect of Vitamin A and Zinc Supplementation on Gastrointestinal Parasitic Infections Among Mexican Children
Authors: Long Kurt Z. , Rosado Jorge L. , Montoya Yura , de Lourdes Solano Maria , Hertzmark Ellen , DuPont Herbert L. , Santos Jose Ignacio
Published: October 2007

OBJECTIVE. Gastrointestinal parasites continue to be an important cause of morbidity and stunting among children in developing countries. We evaluated the effect of vitamin A and zinc supplementation on infections by Giardia lamblia, Ascaris lumbricoides, and Entamoeba histolytica.

METHODS. A randomized, double-blind, placebo-controlled trial was conducted among 707 children who were 6 to 15 months of age and from periurban areas of Mexico City, Mexico, between January 2000 and May 2002. Children, who were assigned to receive either vitamin A every 2 months, a daily zinc supplement, a combined vitamin A and zinc supplement, or a placebo, were followed for 1 year. The primary end points were the 12-month rates and durations of infection for the 3 parasites and rates of parasite-associated diarrheal disease as determined in stools collected once a month and after diarrheal episodes.

RESULTS. G lamblia infections were reduced and A lumbricoides infections increased among children in the combined vitamin A and zinc group or the zinc alone group, respectively. Durations of Giardia infections were reduced among children in all 3 treatment arms, whereas Ascaris infections were reduced in the vitamin A and zinc group. In contrast, E histolytica infection durations were longer among zinc-supplemented children. Finally, E histolytica–and A lumbricoides–associated diarrheal episodes were reduced among children who received zinc alone or a combined vitamin A and zinc supplement, respectively.

CONCLUSIONS. We found that vitamin A and zinc supplementation was associated with distinct parasite-specific health outcomes. Vitamin A plus zinc reduces G lamblia incidence, whereas zinc supplementation increases A lumbricoides incidence but decreases E histolytica–associated diarrhea.
Prehospital Preparedness for Pediatric Mass-Casualty Events
Authors: Shirm Steve , Liggin Rebecca , Dick Rhonda , Graham James
Published: October 2007

OBJECTIVES. Recent events have reiterated the need for well-coordinated planning for mass-casualty events, including those that involve children. The objective of this study was to document the preparedness of prehospital emergency medical services agencies in the United States for the care of children who are involved in mass-casualty events.

METHODS. A national list of all licensed prehospital emergency medical services agencies was prepared through contact with each state's emergency medical services office. A survey was mailed to 3748 emergency medical services agencies that were selected randomly from the national list in November 2004; a second survey was mailed to nonresponders in March 2005. Descriptive statistics were used to describe study variables.

RESULTS. Most (72.9%) agencies reported having a written plan for response to a mass-casualty event, but only 248 (13.3%) reported having pediatric-specific mass-casualty event plans. Most (69%) services reported that they did not have a specific plan for response to a mass-casualty event at a school. Most (62.1%) agencies reported that their mass-casualty event plan does not include provisions for people with special health care needs. Only 19.2% of the services reported using a pediatric-specific triage protocol for mass-casualty events, and 12.3% reported having a pediatrician involved in their medical control. Although most (69.3%) agencies reported participation in a local or regional disaster drill in the past year, fewer than half of those that participated in drills (49.0%) included pediatric victims.

CONCLUSIONS. Although children are among the most vulnerable in the event of disaster, there are substantial deficiencies in the preparedness plans of prehospital emergency medical services agencies in the United States for the care of children in a mass-casualty event.
Sleep Duration From Ages 1 to 10 Years: Variability and Stability in Comparison With Growth
Authors: Jenni Oskar G. , Molinari Luciano , Caflisch Jon A. , Largo Remo H.
Published: October 2007

OBJECTIVE. Our goal was to describe the variability of sleep duration (time in bed per 24 hours) in healthy children from 1 to 10 years of age in comparison with growth measures.

METHODS. A total of 305 children were followed with structured sleep-related interviews and measurements of height and weight 12, 18, and 24 months after birth and then at annual intervals until 10 years of age. SD scores were calculated, and smooth curves were fitted by smoothing splines through the SD scores. The long-term variability channel within children (units SD score) was defined as the difference between the maximum and the minimum of the smooth curves and the short-term variability channel (units SD score) as the difference of the largest and the smallest deviations of the original SD scores from the smooth curve.

RESULTS. Sleep duration remained within a long-term variability channel <0.5 SD score in 21% of the children (34% for height, 21% for weight). Nearly every second child (46%) stayed within a long-term variability channel <1.0 SD score (76% for height, 64% for weight). Sleep duration of ∼90% of all children ran within a long-term variability channel of <2.0 SD score (corresponding, eg, to the range between the 2nd and the 50th percentile). No single child's sleep duration remained within a short-term variability channel <0.5 SD score, indicating fluctuations from year to year (60% for height, 53% for weight). An association between aspects of sleep duration and somatic growth was not observed at any age.

CONCLUSIONS. Sleep duration during early and middle childhood shows large variability among children, as well as trait-like long-term stability and state-like yearly fluctuations within children. An individual approach to the child's sleep behavior is needed; expectations in terms of appropriate sleep duration of the child should be adjusted to the individual sleep need.
Effectiveness of Previous Mumps Vaccination During a Summer Camp Outbreak
Authors: Schaffzin Joshua K. , Pollock Lynn , Schulte Cynthia , Henry Kyle , Dayan Gustavo , Blog Debra , Smith Perry
Published: October 2007

OBJECTIVES. Mumps is a vaccine-preventable disease that may cause outbreaks. In July 2005, an outbreak of mumps occurred during a children's summer camp in upstate New York. An investigation was initiated to describe the cases and evaluate vaccine effectiveness.

METHODS. A retrospective cohort study was conducted among 541 children from the United States and abroad who attended a 1- or 2-month overnight summer camp. Patients with mumps were interviewed; serologic analysis was conducted for 6 case patients. Vaccine effectiveness was calculated by retrospective review of immunization records for 507 attendees who were eligible for vaccination and had verified immunization history.

RESULTS. Thirty-one camp attendees were identified as having mumps (attack rate: 5.7%); 5 (83%) of 6 patients tested had positivity for mumps immunoglobulin M. Of the 507 participants (including 29 patients) with available immunization history, 440 (including 16 [87%] patients) were 2-dose recipients of mumps vaccine (attack rate: 3.6%); 46 participants (including 4 [9%] patients) were 1-dose recipients (attack rate: 8.7%); and 21 (including 9 [4%] patients) were unvaccinated (attack rate: 42.9%). Vaccine effectiveness was 92% for 2 doses and 80% for 1 dose.

CONCLUSIONS. Outbreaks of mumps in settings such as summer camps can occur despite high vaccination rates. Vaccine effectiveness for 2 mumps vaccinations was greater than vaccine effectiveness for 1 mumps vaccination. Therefore, recommendation of 2 mumps vaccinations for summer camp participants continues to be appropriate. Control of mumps disease relies on broad vaccination coupled with correct clinical diagnosis and strict control measures.
Postdischarge Infant Mortality Among Very Low Birth Weight Infants: A Population-Based Study
Authors: Kugelman Amir , Reichman Brian , Chistyakov Irena , Boyko Valentina , Levitski Orna , Lerner-Geva Liat , Riskin Arieh , Bader David ,   in collaboration with the Israel Neonatal Network
Published: October 2007

OBJECTIVE. The objective of this study was to identify factors that were associated with death after discharge from the NICU of very low birth weight infants in a population-based study.

METHODS. From a national cohort of 13430 very low birth weight infants who were born in Israel from 1995 to 2003, 10602 infants were discharged from the hospital and composed the study population. Demographic and clinical data regarding the pregnancy, delivery, and neonatal course were obtained from the Israel national very low birth weight infant database. Data on each case of death during the postdischarge period until 1 year of age were provided by the Ministry of Health from national linked birth and death certificates. Univariate analyses and a multivariable logistic regression analyses were performed to examine the perinatal and neonatal risk factors for postdischarge death.

RESULTS. The postdischarge mortality rate was 7.5 per 1000 (80 of 10602 infants discharged from the hospital). The death rate was significantly higher in non-Jewish infants, infants who were born to young mothers, and infants who were born to low-educated mothers. After adjustment for demographic characteristics and perinatal and neonatal variables, postdischarge mortality was independently associated with congenital malformations, neonatal seizures, necrotizing enterocolitis, and bronchopulmonary dysplasia.

CONCLUSION. Although the postdischarge death rate was relatively low in our cohort of very low birth weight infants, attention should be focused on the subgroups of infants who are at higher risk to decrease their mortality further.
Susceptibility to Nicotine Dependence: The Development and Assessment of Nicotine Dependence in Youth 2 Study
Authors: DiFranza Joseph R. , Savageau Judith A. , Fletcher Kenneth , Pbert Lori , O'Loughlin Jennifer , McNeill Ann D. , Ockene Judith K. , Friedman Karen , Hazelton Jennifer , Wood Connie , Dussault Gretchen , Wellman Robert J.
Published: October 2007

OBJECTIVES. The purpose of this work was to identify characteristics that predict progression from the first inhalation of a cigarette to dependence. We studied a cohort of 1246 public school 6th-graders in 6 Massachusetts communities (mean age at baseline: 12.2 years).

METHODS. We conducted a 4-year prospective study using 11 interviews. We assessed 45 risk factors and measured diminished autonomy over tobacco with the Hooked on Nicotine Checklist and evaluated tobacco dependence according to the International Classification of Diseases, 10th Revision. Cox proportional-hazards models were used.

RESULTS. Among 217 youths who had inhaled from a cigarette, the loss of autonomy over tobacco was predicted by feeling relaxed the first time inhaling from a cigarette and depressed mood. Tobacco dependence was predicted by feeling relaxed, familiarity with Joe Camel, novelty seeking, and depressed mood.

CONCLUSIONS. Once exposure to nicotine had occurred, remarkably few risk factors for smoking consistently contributed to individual differences in susceptibility to the development of dependence or loss of autonomy. An experience of relaxation in response to the first dose of nicotine was the strongest predictor of both dependence and lost autonomy. This association was not explained by trait anxiety or any of the other measured psychosocial factors. These results are discussed in relation to the theory that the process of dependence is initiated by the first dose of nicotine.
Overweight, Race, and Psychological Distress in Children in the Childhood Asthma Management Program
Authors: Bender Bruce G. , Fuhlbrigge Anne , Walders Natalie , Zhang Lening
Published: October 2007

OBJECTIVE. The purpose of this work was to determine whether overweight in youth with mild-to-moderate asthma occurs with increased frequency and is accompanied by impaired psychological functioning.

PATIENTS AND METHODS. The interrelationships among BMI and demographic and psychological characteristics were examined in 1005 children (aged 5–12 years) enrolled in the Childhood Asthma Management Program and seen for repeated visits over 4½ years.

RESULTS. Baseline rates of overweight (BMI for age: ≥95th percentile) were comparable, but rates of overweight risk (BMI for age: 85th to <95th percentile) among children in the Childhood Asthma Management Program were elevated in comparison with the general population of children in the United States. Rates of overweight and overweight risk did not increase over the course of the longitudinal study. Overweight and overweight risk were more frequent among black and Hispanic than white children, although they were not higher relative to same-race groups in the general population. Overweight at baseline was associated with lower IQ, more social withdrawal, and greater internalized psychological distress. As the children became older, the overweight group demonstrated increased evidence of behavior problems and decreased physical activity.

CONCLUSIONS. This study identifies an increase in overweight risk but not overweight in children with mild-to-moderate asthma. Comorbidity between asthma and overweight may be underestimated, because children with severe asthma and those from impoverished backgrounds were not represented in this sample. For the 14% of children who were overweight, some associated psychological difficulties were present in childhood, and additional problems were seen during adolescence. These results suggest a need for programs that encourage greater vigilance and intervention for overweight children with asthma.
Effects of pressure and temperature on sp3 fraction in diamondlike carbon materials
Authors: Zhong Zhanrong , Wang Xinwei , Feng Xuhui
Published: October 2007

In this work, formation of diamond coating is studied using large-scale molecular dynamics (MD) simulation. The diamond coating is studied to explore how and to what extent the temperature and pressure affects the deposition structure. To analyze the coating results, the radial distribution function and the fraction of diamond (sp3 bonds) is calculated. It is found that the sp3 fraction in the deposition structure increases with the temperature and pressure. When the pressure becomes large enough (10 GPa), the effect of the pressure on the coating structure is quite small and the sp3 fraction tends to be constant.
Photoluminescence and acceptor level state of p-type nitrogen-doped MgZnO films
Authors: Wei Z.P. , Yao B. , Wang X.H. , Zhang Z.Z. , Lu Y.M. , Shen D.Z. , Li B.H. , Zhang J.Y. , Zhao D.X. , Fan X.W. , Tang Z.K.
Published: October 2007

A wurtzite nitrogen-doped MgZnO (MgZnO:N) film was grown by plasma-assisted molecular-beam epitaxy (PAMBE) on c-plane sapphire using radical NO as oxygen source and nitrogen dopant. The as-grown film shows n-type conduction at room temperature, but transforms into p-type conduction after annealed. Photoluminescence (PL) spectrum measured at 80 K is dominated by neutral donor-bound exciton emission (D0X) located at 3.522 eV for the n-type MgZnO:N film, but by neutral acceptor-bound exciton emission (A0X) located at 3.515 eV for the p-type MgZnO:N film. By fitting exciton emission intensity of temperature-dependent PL spectra, the binding energies of the D0X and A0X were estimated to be 32 and 43 meV, respectively. Based on the energy shift of exciton emission, the band gap of the MgZnO:N film is estimated to be 3.613 eV, which is 179 meV larger than that of ZnO. Using the Haynes rule, the acceptor energy level of the MgZnO:N film was evaluated to be about 176 meV above the valence band.
Multiaxial deformation characteristic of a Zr-based bulk metallic glass: Variations of the plastic constraint factor underneath a spherical indenter
Authors: Lee Yun-Hee , Kim Ju-Young , Baek Un-Bong , Nahm Seung-Hoon
Published: October 2007

Multiaxial deformation of Zr55Al10Ni5Cu30 metallic glass was investigated by instrumented indentation tests with a spherical indenter. Contrary to the elastic–rigid-plastic behavior of bulk metallic glasses (BMGs), indentation pressure showed a significant increase with increasing indentation strain, and it was ascribed to a rapid transition of the plastic constraint factor (PCF). However, it was impossible to measure the PCF values from the indentation pressures in the Zr-based BMG because information on uniaxial flow stress was insufficient due to the limited flow strain of 2.2%. Here we developed a PCF assessment method using a relative residual depth hf/hmax, which was experimentally confirmed by adopting it to spherical indentations of a steel sample having well-known flow properties. Flow properties of the BMG were calculated using the new PCF assessment method, and the effects of the materials pileup and low strain indentations on PCF and flow properties were discussed.