bluuebunny/crossref_metadata_2025 huggingface dataset:
Surgical Treatment of Appendiceal Adenocarcinoid (Goblet Cell Carcinoid)
Authors: Bucher Pascal , Gervaz Pascal , Ris Frederic , Oulhaci Wassila , Egger Jean‐François , Morel Philippe
Published: August 2005

Adenocarcinoid of the appendix is an infrequent tumor with histologic features of both adenocarcinoma and carcinoid tumor. Although its malignant potential remains unclear, adenocarcinoids seem to be biologically more aggressive than conventional carcinoids. The aim of this study was to analyze long‐term results of surgical treatment for appendiceal adenocarcinoid. A retrospective review (1991–2003) identified seven patients (median age 72, range 27–81 years) treated for appendiceal adenocarcinoid. The clinical data of these patients were reviewed. Follow‐up was complete for all patients (median 60 months, range 24–108 months). Most cases presented with associated acute appendicitis (71%). First intention surgery consisted of appendectomy (m = 6) and right hemicolectomy (m = 1). In three patients, additional surgical procedures were performed (right colectomy). Indications for colectomy were tumor size (three cases) associated with appendectomy margin invasion in one case. One patient with lymph node and peritoneal involvement experienced recurrence 9 months after hemicolectomy and died of the disease at 2 years. One patient subsequently died of colon carcinoma 6 years after adenocarcinoid treatment. Five patients were alive without disease at the time of the last follow‐up. Synchronous or metachronous colon carcinomas developed in three patients (43%). Our results suggest that appendectomy alone could be used for appendiceal adenocarcinoid provided that the tumor (1) is less than 1 cm; (2) does not extend beyond the appendix adventitia; (3) has less than 2 mitoses/10 high power fields; and (4) has surgical margins that are tumor free. Otherwise, carcinologic right colectomy seems to be indicated. The risk for developing colorectal adenocarcinoma seems to be extremely high in patients treated for appendiceal adenocarcinoid and warrants close follow‐up with colonoscopic screening.
Outcomes in Oncologic Surgery: Does Volume Make a Difference?
Authors: Bentrem David J. , Brennan Murray F.
Published: August 2005

Commonly performed elective surgical procedures on the alimentary tract are carried out with low morbidity and low mortality in most hospitals in the United States. There are some procedures on the alimentary tract that are performed with a relatively low frequency and are associated with higher mortality. Volume is a surrogate marker associated with improved outcome, with relative differences being dependent on the complexity of the procedure and the frequency with which it is done. Both surgeon and institutional volume matters, but it seems that improved operative mortality can be reached with lower surgeon volume in high‐volume institutions. It appears that volume can be substituted in part for by specialization and training, with improved outcomes based on specialist credentials and fellowship training.
The Volume–Outcome Relationship: Don’t Believe Everything You See
Authors: Christian Caprice K. , Gustafson Michael L. , Betensky Rebecca A. , Daley Jennifer , Zinner Michael J.
Published: August 2005

This paper investigates methodological limitations of the volume–outcome relationship. A brief overview of quality measurement is followed by a discussion of two important aspects of the relationship.
Behavioural factors related to metabolic control in patients with phenylketonuria
Authors: Crone M. R. , van Spronsen F. J. , Oudshoorn K. , Bekhof J. , van Rijn G. , Verkerk P. H.
Published: September 2005

Background. The objective of this study was to determine the importance of parental factors possibly related to dietary control in early and continuously treated patients with phenylketonuria (PKU). Methods. A questionnaire was disseminated among parents of 238 patients with PKU born after the nationwide introduction of newborn screening for PKU (1 September 1974) until 31 December 1995. The questionnaire was based on a behavioural model measuring people's attitudes, subjective norms, and self‐efficacy. Dietary control was defined on the basis of mean phenyl‐ alanine (Phe) concentration of the PKU patients measured between 1 January 1994 and 31 December 1996. Results. Response rate was 71%. Attitudes: children of parents who believed that their child adheres well to the diet, even if his or her Phe concentrations are sometimes too high, had lower Phe concentrations than children of parents who disagree with this statement (adjusted difference −103 μmol/L, p < 0.001). Subjective norm: Phe concentrations were higher when parents answered that their relatives did not approve when their child deviates from the diet (p = 0.004). Self‐efficacy: children of parents who reported difficulties in having their child eat the synthetic protein substitute three times a day had higher Phe concentrations than those of parents who did not have such difficulties (adjusted difference 156 μmol/L, p = 0.007). Conclusion. More attention should be given to parents having their child eat the synthetic protein substitute at least three times a day and to teaching parents to keep strictly to the diet without being too rigid. These factors were strongly associated to dietary control and may be amenable to change.
Body composition in young adults with inborn errors of protein metabolism—A pilot study
Authors: Wilcox G. , Strauss B. J. G. , Francis D. E. M. , Upton H. , Boneh A.
Published: September 2005

The natural history of inborn errors of protein metabolism and the long‐term effects of prescribed semisynthetic therapeutic diets are largely unknown. We assessed body composition, measuring body‐fat mass and distribution, fat‐free mass, total body protein, total body potassium, bone density and skeletal muscle mass, in young adults (age > 18 years; 6 female, 5 male) with inborn errors of protein metabolism maintained on long‐term low‐protein diets, compared with controls. Female patients were significantly shorter (159.4 cm vs 169.2 cm, p = 0.013) and had higher BMI (25.3 vs 22.0 kg/m2, p < 0.05), abdominal to gluteal circumference ratio (0.84 vs 0.73, p = 0.011), percentage body fat (42.3% vs 29.5%, p < 0.005) and ratio of central to peripheral body fat (1.15 vs 0.86, p < 0.05) than controls. Male patients had lower height‐adjusted total body bone mineral content (0.9 vs 1.02 g/m2, p < 0.04) and skeletal muscle mass (31.1 vs 36.3 kg, p < 0.04) than controls. Compared with controls, patients'nitrogen index was significantly lower (0.91 vs 1.03, p < 0.01), consistent with lower total body protein. Potassium index was significantly higher (121.2% vs 110.4%, p < 0.03), consistent with higher body cell mass, or intracellular water. Documentation of body composition in larger patient series is important to elucidate whether these results reflect increased risks (hence opportunities for prevention) of bone disease, metabolic syndrome and cardiovascular disease in this population.
A new protein substitute for adolescents and adults with maple syrup urine disease (MSUD)
Authors: Hallam P. , Lilburn M. , Lee P. J.
Published: September 2005

Aim.The aim was to study the efficacy and acceptability of MSUD Express in adolescent and adult patients with maple syrup urine disease (MSUD). Background. There are difficulties associated with current protein substitutes designed for adolescents and adults with MSUD. This can affect their metabolic control. MSUD Express is a new low‐volume, nutritionally complete protein substitute, free from leucine, isoleucine and valine and designed specifically for older patients with MSUD. Methods. Four patients with MSUD were included in the trial (aged 16–41 years). Product dosage was 4× 25 g sachets per day, providing 1264 kJ and 72 g amino acids: more than adequately meeting requirements for all micronutrients. Results. At the start of the study, the mean (range) of the previous eight leucine concentrations (on MSUD Aid III) was 564 μmol/L (430–817 μmol/L) and during the study (on MSUD Express) was 382 μmol/L (181–603 μmol/L). The average percentage fall in mean leucine concentrations was 32%. In patients 2, 3 and 4, low leucine levels resulted in an increase in the natural protein allowance per day. MSUD Express was rated as ‘excellent’ or ‘good’ by all patients on the basis of appearance, taste, smell and texture. All patients found the product ‘very easy’ to prepare and found it ‘easy’ or ‘very easy’ to take outside the home. Conclusion. All patients thought the preparation of MSUD Express was ‘very easy’. Metabolic control (mean leucine concentrations) improved in all of the patients. In three patients this meant that an increase in the amount of natural protein in the diet was possible. All patients elected to stay on MSUD Express after the trial period. MSUD Express appears to be an effective and acceptable product, offering an alternative to current protein substitutes available for older people with MSUD.
Heparan sulfate levels in mucopolysaccharidoses and mucolipidoses
Authors: Tomatsu S. , Gutierrez M. A. , Ishimaru T. , Peña O. M. , Montaño A. M. , Maeda H. , Velez‐Castrillon S. , Nishioka T. , Fachel A. A. , Cooper A. , Thornley M. , Wraith E. , Barrera L. A. , Laybauer L. S. , Giugliani R. , Schwartz I. V. , Frenking G. Schulze , Beck M. , Kircher S. G. , Paschke E. , Yamaguchi S. , Ullrich K. , Isogai K. , Suzuki Y. , Orii T. , Noguchi A.
Published: September 2005

Glycosaminoglycans are accumulated in both mucopolysaccharidoses (MPS) and mucolipidoses (ML). MPS I, II, III and VII and ML II and ML III patients cannot properly degrade heparan sulphate (HS). In spite of the importance of HS storage in the metabolic pathway in these diseases, blood and urine HS levels have not been determined systematically using a simple and economical method. Using a new ELISA method using anti‐HS antibodies, HS concentrations in blood and urine were determined in MPS and ML II and ML III patients. HS concentrations were determined in 156 plasma samples from MPS I (n = 23), MPS II (n = 26), MPS III (n = 24), MPS IV (n = 62), MPS VI (n = 5), MPS VII (n = 5), ML II (n = 8) and ML III (n = 3), and 205 urine samples from MPS I (n = 33), MPS II (n = 33), MPS III (n = 30), MPS IV (n = 82), MPS VI (n = 7), MPS VII (n = 9), ML II (n = 8) and ML III (n = 3). The ELISA method used monoclonal antibodies against HS. MPS I, II, III and VII and ML II and III patients had significant elevation in plasma HS, compared to the age‐matched controls (p < 0.0001). Eighty‐three out of 89 (93.3%) of individual values in the above MPS types and ML were above the mean +2SD of the controls. In urine samples, 75% of individual values in patients with those types were above the mean +2SD of the controls. In contrast to the previous understanding of the HS metabolic pathway, plasma HS levels in all five MPS VI and 15% of MPS IV patients were elevated above the mean +2SD of the controls. These findings suggest that HS concentration determined by ELISA, especially in plasma, could be a helpful marker for detection of the most severe MPS I, II, III, VI and VII and ML II, distinguishing them from normal populations.
Living with phenylketonuria: Perspectives of patients and their families
Authors: Bilginsoy C. , Waitzman N. , Leonard C. O. , Ernst S. L.
Published: September 2005

This study surveyed PKU patients and their primary caretakers to assess their current management practices, the barriers to effective management, and the potential utility of a home monitor in managing PKU. A survey instrument was mailed to caretakers of all 50 patients with PKU in Utah between the ages of 2 and 18 years in 1997 (response rate 64%). It included separate components for caretakers and patients aged 10 to 18 years. Although there was uneven compliance with recommended practices, caretakers universally recognized the negative consequences of not adhering to the low‐protein diet. There was, however, disagreement regarding such consequences among the older children surveyed. The primary obstacles cited to better adherence were time constraints and stress associated with food preparation and record‐keeping, and the restrictions imposed on social life. Phenylalanine test results were regarded as the principal signal for the need for dietary adjustment. Despite the facts that obstacles to dietary adherence are multifaceted and that no single intervention would therefore serve as a panacea, a large majority of respondents believed a home monitor would facilitate better management of PKU through more regular and timely feedback.
A high‐conductance mode of a poly‐3‐hydroxybutyrate/calcium/polyphosphate channel isolated from competent Escherichia coli cells
Authors: Pavlov Evgeny , Grimbly Chelsey , Diao Catherine T.M. , French Robert J.
Published: August 2005

Reconstitution into planar lipid bilayers of a poly‐3‐hydroxybutyrate/calcium/polyphosphate (PHB/Ca2+/polyP) complex from Escherichia coli membranes yields cationic‐selective, 100 pS channels (Das, S., Lengweiler, U.D., Seebach, D. and Reusch, R.N. (1997) Proof for a non‐proteinaceous calcium‐selective channel in Escherichia coli by total synthesis from (R)‐3‐hydroxybutanoic acid and inorganic polyphosphate. Proc. Natl. Acad. Sci. USA 94, 9075–9079). Here, we report that this complex can also form larger, weakly selective pores, with a maximal conductance ranging from 250 pS to 1 nS in different experiments (symmetric 150 mM KCl). Single channels were inhibited by lanthanum (IC50
= 42 ± 4 μM, means ± S.E.M.) with an unusually high Hill coefficient (8.4 ± 1.2). Transition to low‐conductance states (<250 pS) was favored by increased membrane polarization (∣V∣ ⩾ 50 mV). High conductance states (>250 pS) may reflect conformations important for genetic transformability, or “competence”, of the bacterial cells, which requires the presence of the PHB/Ca2+/polyP complex in the membrane.
Incorporation of oxygen into the succinate co‐product of iron(II) and 2‐oxoglutarate dependent oxygenases from bacteria, plants and humans
Authors: Welford Richard W.D. , Kirkpatrick Joanna.M. , McNeill Luke A. , Puri Munish , Oldham Neil J. , Schofield Christopher J.
Published: August 2005

The ferrous iron and 2‐oxoglutarate (2OG) dependent oxygenases catalyse two electron oxidation reactions by coupling the oxidation of substrate to the oxidative decarboxylation of 2OG, giving succinate and carbon dioxide coproducts. The evidence available on the level of incorporation of one atom from dioxygen into succinate is inconclusive. Here, we demonstrate that five members of the 2OG oxygenase family, AlkB from Escherichia coli, anthocyanidin synthase and flavonol synthase from Arabidopsis thaliana, and prolyl hydroxylase domain enzyme 2 and factor inhibiting hypoxia‐inducible factor‐1 from Homo sapiens all incorporate a single oxygen atom, almost exclusively derived from dioxygen, into the succinate co‐product.
IGF‐1 and BDNF promote chick bulbospinal neurite outgrowth in vitro
Authors: Salie Rishard , Steeves John D.
Published: September 2005

Injured neurons in the CNS do not experience significant functional regeneration and so spinal cord insult often results in permanently compromised locomotor ability. The capability of a severed axon to re‐grow is thought to depend on numerous factors, one of which is the decreased availability of neurotrophic factors. Application of trophic factors to axotomized neurons has been shown to enhance survival and neurite outgrowth. Although brainstem–spinal connections play a pivotal role in motor dysfunction after spinal cord injury, relatively little is known about the trophic sensitivity of these populations. This study explores the response of bulbospinal populations to various trophic factors. Several growth factors were initially examined for potential trophic effects on the projection neurons of the brainstem. Brain derived neurotrophic factor (BDNF) and insulin‐like growth factor (IGF‐1) significantly enhance mean process length in both the vestibulospinal neurons and spinal projection neurons from the raphe nuclei. Nerve growth factor (NGF), neurotrophin‐4 (NT‐4) and glial derived neurotrophic factor (GDNF) did not effect process outgrowth in vestibulospinal neurons. At the developmental stages used in this study, it was determined that receptors for BDNF and IGF‐1 were present both on bulbospinal neurons and on surrounding cells with a non‐neuronal morphology.
Caveolin isoform expression during differentiation of C6 glioma cells
Authors: Silva W.I. , Maldonado H.M. , Velázquez G. , Rubio‐Dávila M. , Miranda J.D. , Aquino E. , Mayol N. , Cruz‐Torres A. , Jardón J. , Salgado‐Villanueva I.K.
Published: August 2005

Caveolae, a specialized form of lipid rafts, are cholesterol‐ and sphingolipid‐rich membrane microdomains implicated in potocytosis, endocytosis, transcytosis, and as platforms for signal transduction. One of the major constituents of caveolae are three highly homologous caveolin isoforms (caveolin‐1, caveolin‐2, and caveolin‐3). The present study expands the analysis of caveolin isoform expression in C6 glioma cells. Three complementary approaches were used to assess their differential expression during the dibutyryl‐cyclic AMP‐induced differentiation of C6 cells into an astrocyte‐like phenotype. Immunoblotting, conventional RT‐PCR, and real‐time RT‐PCR analysis established the expression of the caveolin‐3 isoform in C6 cells, in addition to caveolin‐1 and caveolin‐2. Similar to the other isoforms, caveolin‐3 was associated with light‐density, detergent‐insoluble caveolae membrane fractions obtained using sucrose‐density gradient centrifugation. The three caveolin isoforms display different temporal patterns of mRNA/protein expression during the differentiation of C6 cells. Western blot and real‐time RT‐PCR analysis demonstrate that caveolin‐1 and caveolin‐2 are up‐regulated during the late stages of the differentiation of C6 cells. Meanwhile, caveolin‐3 is gradually down‐regulated during the differentiation process. Indirect immunofluorescence analysis via laser‐scanning confocal microscopy reveals that the three caveolin isoforms display similar subcellular distribution patterns. In addition, co‐localization of caveolin‐1/caveolin‐2 and caveolin‐1/caveolin‐3 was detected in both C6 glioma phenotypes. The findings reveal a differential temporal pattern of caveolin gene expression during phenotypic differentiation of C6 glioma cells, with potential implications to developmental and degenerative events in the brain.
Nasal Obstruction is the Key Symptom in Hay Fever Patients
Authors: Ciprandi Giorgio , Cirillo Cirillo , Klersy Catherine , Marseglia Gian Luigi , Caimmi Davide , Vizzaccaro Andrea
Published: September 2005

BACKGROUND

Allergic rhinitis is characterized by a Th2‐dependent inflammation. Nasal obstruction largely depends on allergic inflammation.

OBJECTIVE

The aim of this study was to evaluate the possible role of the symptom nasal obstruction in assessing patients with hay fever.

METHODS

Fifty patients (mean age, 23.7 ± 4.9 years) with hay fever were evaluated both during and outside pollen season. All of them had moderate‐severe grade of nasal obstruction. Total symptom score (TSS), rhinomanometry, nasal lavage, nasal scraping, spirometry, and methacholine bronchial challenge were performed in all subjects.

RESULTS

During the pollen season, patients with severe nasal obstruction showed significantly higher values of TSS, IL‐4, IL‐5, IL‐8, nasal eosinophils and neutrophils, and significantly lower values of nasal airflow, IFNγ, FEV1, FVC, and FEF 25‐75 in comparison with patients with moderate nasal obstruction. Twenty (83%) patients with severe nasal obstruction showed bronchial hyperreactivity (BHR), whereas only 6 (25%) patients with moderate nasal obstruction had BHR. Outside the pollen season overlapping results were observed.

CONCLUSIONS

This study provides evidence about the key role played by nasal obstruction in assessing patients with allergic rhinitis.
The Role of Vestibular Rehabilitation in the Treatment of Meniere's Disease
Authors: Gottshall Kim R. , Hoffer Michael E. , Moore Robert J. , Balough Ben J.
Published: September 2005

OBJECTIVE

To study the role of vestibular rehabilitation is treating patients with Meniere's disease.

METHODS

We examined all Meniere's patients presenting to our tertiary care specialized vestibular clinic during a 1‐year period. All patients underwent a standardized history and physical examination, a complete auditory‐vestibular test battery, and a set of physical therapy tools to measure balance function.

RESULTS

A subset of patients suffered from disequilibrium or unsteadiness between attacks. Once the acute fluctuating symptoms of Meniere's were controlled in this group of individuals, all of them underwent vestibular physical therapy and demonstrated significant improvement in balance function on both objective and self‐report tests.

CONCLUSIONS

Due to the fluctuating nature of the disorder, vestibular physical therapy has had a limited role in the treatment of Meniere's disease. In general, rehabilitation has been used only as a postoperative treatment for the acute vertigo seen after vestibular neurectomy or labyrinthectomy. This is the first report advocating the role of vestibular physical therapy in a group of patients receiving medical therapy of intraear medicines (other that gentamicin).
Variations in effects of monetary policy on stock market returns in the past four decades
Authors: He Ling T.
Published: August 2005

Stock prices are sensitive to monetary policy. However, the sensitivities are not stable over time. A drastic change in monetary policy can alter effects of monetary policy on stock returns. This study finds that stock prices can be affected by current changes, unexpected changes, or near‐future changes in the funds/discount rates, due to different policy goals or targets in different periods. Specifically, this study provides empirical evidence that monetary policy influences the stock market in different ways in the 1960s, the 1970s, the Volcker and Greenspan periods.
Human Vero cytotoxigenic Escherichia coli (VTEC) O157 infection linked to birds
Authors: EJIDOKUN O. O. , WALSH A. , BARNETT J. , HOPE Y. , ELLIS S. , SHARP M. W. , PAIBA G. A. , LOGAN M. , WILLSHAW G. A. , CHEASTY T.
Published: September 2005

Vero cytotoxin-producing Escherichia coli O157 (VTEC O157) infections are a threat to public health. VTEC O157 has been isolated from gulls but evidence of transmission to humans from birds has not been reported. We recount an incident of VTEC O157 infection affecting two sibling children who had no direct contact with farm animals. An outbreak control team was convened to investigate the source of infection, its likely mode of transmission, and to advise on control measures. Human and veterinary samples were examined and the human isolates were found to be identical to an isolate from a sample of bird (rook) faeces. Cattle, rabbit and environmental samples were negative. This report provides evidence that birds may act as intermediaries for human infection with VTEC O157.
Dependencies of high‐latitude plasma convection: Consideration of interplanetary magnetic field, seasonal, and universal time factors in statistical patterns
Authors: Ruohoniemi J. M. , Greenwald R. A.
Published: August 2005

The database of the nine radars of the Super Dual Auroral Radar Network (SuperDARN) in the northern hemisphere has been analyzed for information on factors that influence the convection of plasma in the high‐latitude ionosphere. The velocity measurements were collected over the period 1998–2002. The data were first used to derive a new statistical model of convection that improves upon the earlier one‐radar model of Ruohoniemi and Greenwald (1996) in its specification of the dependence of the convection pattern on the magnitude and direction of the IMF in the GSM Y‐Z plane. We then derived average patterns for secondary sortings by season, year, and radar. Such dependencies as emerged were most clearly seen by contrasting the results for By+ and By−. The seasonal effect in the convection pattern is found to have similarities to that of the sign of By. In particular, the combination of By+/summer (By−/winter) reinforces the tendency of the By sign factor to sculpt the dusk and dawn cells into more round/crescent (crescent/round) shapes and to shift the crescent cell across the midnight MLT meridian. However, these combinations are associated with lower estimates of the total cross polar cap potential drop, ΦPC, while the nonreinforcing combinations produce elevated ΦPC, especially By−/summer. There is an overall tendency for ΦPC to increase from winter to summer, although the pure seasonal effect on the potential drop is weaker than that of the By−sign/season factor. We did not find pronounced differences among the patterns derived for the 5 individual years, which spanned the most recent interval of solar cycle maximum. Sorting by radar, we found few differences among the patterns for By+, but for By−, variations emerged that are consistent with a possible dependence on universal time (UT). The impacts of season and UT on convection in the high‐latitude ionosphere thus depends on the IMF, especially the sign of By. We speculate that variability in the ionospheric conductivity has a greater effect on magnetosphere‐ionosphere coupling under By− conditions.
Origin and evolution of deep plasmaspheric notches
Authors: Gallagher D. L. , Adrian M. L. , Liemohn M. W.
Published: August 2005

Deep plasmaspheric notches can extend over more than 2 RE in radial distance and 3 hours MLT in the magnetic equatorial plane, as observed by the extreme ultraviolet (EUV) imager on the IMAGE mission. They are among the largest evacuated features in the exterior plasmaspheric boundary. They can last for days and exhibit a variety of shapes. It appears that weak convection and limited erosion precedes notch formation at the westward, near‐Earth edge of the convection plume. Eighteen clear notch events were found and analyzed in 2000. Among these events, notches were found to drift as slowly as 44% of corotation. In only one case was a notch found to drift at the corotation rate within measurement error. On average, these notches drift at about 21.5 h d−1 or 90% of the corotational rate. Notches sometimes exhibit an interior structure that appears as an extended prominence of dense plasma, which forms a W‐ or M‐like feature in IMAGE/EUV images, depending on viewing perspective. Initial modeling suggests that notches and notch prominences may be caused in part by intense small‐scale potential structures that result from the localized injection of ring current plasma. Plasma filling rates during recovery are examined in three L shell ranges from L = 2 to L = 3.5 with rates ranging from 5 to 140 cm−3 d−1. Plasma loss during a minor substorm is found to extend to surprisingly low L shell with rates ranging from 100 to 130 cm−3 d−1 across the L shells examined.
Global MHD simulations of the strongly driven magnetosphere: Modeling of the transpolar potential saturation
Authors: Merkin V. G. , Sharma A. S. , Papadopoulos K. , Milikh G. , Lyon J. , Goodrich C.
Published: August 2005

When the magnetosphere‐ionosphere system is driven strongly by the solar wind, the ionospheric transpolar potential tends to saturate. The global MHD simulations are used to study this phenomenon and, in particular, the role the ionospheric conductance plays in controlling the dayside reconnection and the transpolar potentials. The feedback of the ionospheric conductance enhanced due to a high solar wind activity leads to changes in the global configuration of the solar wind‐magnetosphere‐ionosphere system. The changes in the size of the magnetopause and the associated reconfiguration of the magnetosheath flow lead to a reduction of the reconnection and consequently the transpolar potentials. Thus the solar wind has two competing effects on the transpolar potential, namely, the direct amplification by the solar wind electric field and the feedback of the ionospheric conductance on the reconnection potential.
Influence of terrestrial ecosystems and topography on coastal CO2 measurements: A case study at Trinidad Head, California
Authors: Riley W. J. , Randerson J. T. , Foster P. N. , Lueker T. J.
Published: September 2005

Coastal stations are critical for interpretation of continental‐scale CO2 exchanges although the impacts of land and sea breezes, local topography, katabatic winds, and CO2 transport from nearby terrestrial ecosystems are not well characterized. We applied a modeling framework that couples meteorological (MM5), land‐surface (LSM1), and tracer models to investigate the impact of these factors on coastal CO2 measurements. Model predictions compared well with measurements over 4 months at our case study site (Trinidad Head, California). We predicted that during midday and under strong onshore wind conditions, positive and negative CO2 anomalies from the assumed “background” marine layer air were sampled at the station. These anomalies resulted from two classes of mechanisms that couple transport and recent terrestrial ecosystem exchanges. First, and most important, are local and large‐scale recirculation of nighttime positive CO2 anomalies resulting from katabatic flows off the coastal mountain range. Second, negative anomalies generated by daytime net ecosystem uptake can be transported offshore in the residual layer and then entrained in the marine boundary layer. We predicted monthly averaged CO2 anomalies associated with terrestrial exchanges of 0.53, 0.34, 3.1, and 0.05 ppm during March, June, September, and December of 2002. Positive anomalies from nighttime ecosystem respiration were more likely to be sampled than are negative anomalies associated with daytime net ecosystem uptake. Current atmospheric models used in continental‐scale inverse studies do not resolve these two classes of mechanisms and therefore may infer incorrect CO2 exchange rates.
On the relationships between slab dip, back‐arc stress, upper plate absolute motion, and crustal nature in subduction zones
Authors: Lallemand Serge , Heuret Arnauld , Boutelier David
Published: September 2005

Statistical analysis of modern oceanic subduction zone parameters, such as the age of a downgoing plate or the absolute plate motions, is performed in order to investigate which parameter controls the dip of a slab and, conversely, what the influence of slab geometry is on upper plate behavior. For that purpose, parameters have been determined from global databases along 159 transects from all subduction zones that are not perturbed by nearby collision or ridge/plateau/seamount subduction. On the basis of tomographic images, slabs that penetrate through, or lie on, the 670 km discontinuity are also identified. The results of the statistical analysis are as follows: (1) Back‐arc stress correlates with slab dip, i.e., back‐arc spreading is observed for deep dips (deeper than 125 km) larger than 50°, whereas back‐arc shortening occurs only for deep dips less than 30°. (2) Slab dip correlates with absolute motion of the overriding plate. The correlation is even better when the slab lies on, or even more penetrates through, the 670 km discontinuity. (3) Slabs dip more steeply, by about 20° on average, beneath oceanic overriding plates than beneath continental ones. (4) Slabs dip more steeply on average by about 10° near edges. (5) Slab dip does not correlate with the magnitude of slab pull, the age of subducting lithosphere at the trench, the thermal regime of the subducting lithosphere, the convergence rate, or the subduction polarity (east versus west). The present study provides evidence that the upper plate absolute motion plays an important role on slab dip, as well as on upper plate strain. Retreating overriding plates are often oceanic ones and thus may partially explain the steeper slab dips beneath oceanic upper plates. One can infer that low slab dips correlate well with compression in continental advancing upper plates, whereas steep dips are often associated with extension in oceanic retreating upper plates. Excess weight of old slabs is often counterbalanced by other forces, probably asthenospheric in origin, such as lateral mantle flow near slab edges or anchor forces, to determine slab dip.
Mantle convection with reversing mobile plates: A benchmark study
Authors: Koglin Donald E. , Ghias Sanaz R. , King Scott D. , Jarvis Gary T. , Lowman Julian P.
Published: September 2005

Recent investigations of mantle convection with mobile plates have documented a mode of convection with periodic and/or aperiodic plate reversals (2‐D) or reorganizations (3‐D). We show that it is possible to calibrate plate formulations so that three different modeling methods reproduce the global flow diagnostics to within 3%. In 2‐D calculations, plate reversals are independent of the method of plate generation once the calculations are tuned to reproduce the same physical characteristics (e.g., Nusselt number and plate velocity). The periods of oscillation of the flow reversals from three different plate methods agree to within 4%.
A PTFE membrane for the in situ extraction of dissolved gases in natural waters: Theory and applications
Authors: De Gregorio S. , Gurrieri S. , Valenza M.
Published: September 2005

A new method for extracting dissolved gases in natural waters has been developed and tested, both in the laboratory and in the field. The sampling device consists of a polytetrafluroethylene (PTFE) tube (waterproof and gas permeable) sealed at one end and connected to a glass sample holder at the other end. The device is pre‐evacuated and subsequently dipped in water, where the dissolved gases permeate through the PTFE tube until the pressure inside the system reaches equilibrium. A theoretical model describing the time variation in partial gas pressure inside a sampling device has been elaborated, combining the mass balance and “Solution‐Diffusion Model” (which describes the gas permeation process through a PTFE membrane). This theoretical model was used to predict the temporal evolution of the partial pressure of each gas species in the sampling device. The model was validated by numerous laboratory tests. The method was applied to the groundwater of Vulcano Island (southern Italy). The results suggest that the new sampling device could easily extract the dissolved gases from water in order to determine their chemical and isotopic composition.
Observations of infragravity waves at the Monterey ocean bottom broadband station (MOBB)
Authors: Dolenc David , Romanowicz Barbara , Stakes Debra , McGill Paul , Neuhauser Doug
Published: August 2005

Infragravity waves can be observed at the 1000 m deep ocean bottom broadband seismic station MOBB on stormy as well as quiet days. When compared to the energy of the short‐period ocean waves recorded at the local buoys, infragravity waves in the longer than 20 s period band are found to be mainly locally generated from shorter‐period waves. Two types of modulation of the infragravity signal are observed. First, the entire infragravity band signal is modulated in‐phase with tides, possibly as a result of the nonlinear exchange of energy between the short‐period waves and tidal currents. Second, a longer‐period modulation of the infragravity signal is observed and is best correlated with the energy of the 14 s period ocean waves. This correlation indicates that the mechanism of generation of double frequency microseisms and infragravity waves are likely strongly related. Previously recorded data during the Oregon ULF/VLF experiment at 600 m water depth also indicate that infragravity waves are primarily locally generated.
Interaction between direct penetration and disturbance dynamo electric fields in the storm‐time equatorial ionosphere
Authors: Maruyama N. , Richmond A. D. , Fuller‐Rowell T. J. , Codrescu M. V. , Sazykin S. , Toffoletto F. R. , Spiro R. W. , Millward G. H.
Published: September 2005

The direct penetration of the high‐latitude electric field to lower latitudes, and the disturbance dynamo, both play a significant role in restructuring the storm‐time equatorial ionosphere and thermosphere. Although the fundamental mechanisms generating each component of the disturbance electric field are well understood, it is difficult to identify the contribution from each source in a particular observation. In order to investigate the relative contributions of the two processes, their interactions, and their impact on the equatorial ionosphere and thermosphere, the response to the March 31, 2001, storm has been modeled using the Rice Convection Model (RCM) and the Coupled Thermosphere‐Ionosphere‐Plasmasphere‐Electrodynamics (CTIPe) model. The mid‐ and low‐latitude electric fields from RCM have been imposed as a driver of CTIPe, in addition to the high latitude magnetospheric sources of ion convection and auroral precipitation. The high latitude sources force the global storm‐time wind fields, which act as the driver of the disturbance dynamo electric fields. The magnitudes of the two sources of storm‐time equatorial electric field are compared for the March 2001 storm period. During daytime, and at the early stage of the storm, the penetration electric field is dominant; while at night, the penetration and disturbance dynamo effects are comparable. Both sources are sufficient to cause significant restructuring of the low latitude ionosphere. Our results also demonstrate that the mid‐ and low‐latitude conductivity and neutral wind changes initiated by the direct penetration electric field preferentially at night are sufficient to alter the subsequent development of the disturbance dynamo.
A high‐latitude 8‐hour wave in the mesosphere and lower thermosphere
Authors: Wu Q. , Mitchell N. J. , Killeen T. L. , Solomon S. C. , Younger P. T.
Published: August 2005

We used simultaneous multimission Fabry Perot interferometer neutral wind, airglow intensity, and temperature observations at Resolute (75°N) and meteor radar neutral wind observation at Esrange (68°N) to study a wave event with a period of close to 8 hours. On the basis of two days' worth of observations in October, we were able to show that during this event the 8‐hour wave only appeared at Resolute (75°N) and damped from 87‐ to 97‐km altitude with a vertical wavelength of ∼35 km. The OH emission temperature 8‐hour oscillation was leading that in the OH emission brightness, resulting a negative phase of Krassovsky ratio, which may be related to the damping of the wave. The 8‐hour wave also appears to be affected by planetary waves, resulting in a small phase shift for the wave from the first to the second day.
Extended Therapeutic Window and Functional Recovery after Intraarterial Administration of Neuregulin-1 after Focal Ischemic Stroke
Authors: Xu Zhenfeng , Croslan DaJoie R , Harris Adalynn E , Ford Gregory D , Ford Byron D
Published: August 2005

We have previously shown that neuregulin-1 (NRG-1) protects neurons from ischemic brain injury if administered before focal stroke. Here, we examined the therapeutic window and functional recovery after NRG-1 treatment in rats subjected to 90 mins of middle cerebral artery occlusion (MCAO) and 24 h of reperfusion. Neuregulin-1 (2.5 ng/kg bolus, 1.25 ng/kg/min infusion) reduced infarct volume by 89.2% ± 41.9% (mean ± s.d.; n = 8; P < 0.01) if administered immediately after the onset of reperfusion. Neuroprotection was also evident if NRG-1 was administered 4 h (66.4% ± 52.6%; n = 7; P < 0.01) and 12 h (57.0% ± 20.8%; n = 8; P < 0.01) after reperfusion. Neuregulin-1 administration also resulted in a significant improvement of functional neurologic outcome compared with vehicle-treated animals (32.1% ± 5.7%; n 9; P < 0.01). The neuroprotective effect of the single administration of NRG-1 was seen as long as 2 weeks after treatment. Neurons labeled with the neurodegeneration marker dye Fluoro-JadeB were observed after MCAO in the cortex, but the numbers were significantly reduced after NRG-1 treatment. These results indicate that NRG-1 is a potent neuroprotective compound with an extended therapeutic window that has practical therapeutic potential in treating individuals after ischemic brain injury.
Hierarchical self-assembly of actin bundle networks: Gels with surface protein skin layers
Authors: Hirst Linda S. , Pynn Roger , Bruinsma Robijn F. , Safinya Cyrus R.
Published: September 2005

The networklike structure of actin bundles formed with the cross-linking protein α-actinin has been investigated via x-ray scattering and confocal fluorescence microscopy over a wide range of α-actinin/F-actin ratios. We describe the hierarchical structure of bundle gels formed at high ratios. Isotropic actin bundle gels form via cluster-cluster aggregation in the diffusion-limited aggregation regime at high α-actinin/actin ratios. This process is clearly observed by confocal fluorescence microscopy. Polylysine is investigated as an alternative bundling agent in the high-ratio regime and the effects of F-actin length are also discussed. One particularly fascinating aspect of this system is the presence of a structured skin layer at the gel/water interface. Confocal microscopy has elucidated the full three-dimensional structure of this layer and revealed several interesting morphologies. The protein skin layer is a micron-scale structure composed of a directed network of bundles and exhibits flat, crumpled, and tubelike shapes. We show that crumpling of the skin layer results from stresses due to the underlying gel. These biologically based geometric structures may detach from the gel, demonstrating potential for the generation of biological scaffolds with defined shapes for applications in cell encapsulation and tissue engineering. We demonstrate manipulation of the skin layer, producing hemispherical structures in solution.
Low-frequency Raman spectra of sub- and supercritical CO2: Qualitative analysis of the diffusion coefficient behavior
Authors: Idrissi A. , Longelin S. , Damay P. , Leclercq F.
Published: August 2005

We report the results of the low-frequency Raman experiments on CO2 which were carried out in a wide density range, along the liquid-gas coexistence curve in a temperature range of 293–303 K, and on the critical isochore of 94.4cm3mol−1 in a temperature range of 304–315 K. In our approach, the qualitative behavior of the diffusion coefficient D is predicted, assuming the following: first, that the low-frequency Raman spectra can be interpreted in terms of the translation rotation motions; second, that the random force could be replaced by the total force to calculate the friction coefficient; and finally, that the Einstein frequency is associated with the position of the maximum of the low-frequency Raman spectrum. The results show that the diffusion coefficient increases along the coexistence curve, and its values are almost constant on the critical isochore. The predicted values reproduce qualitatively those obtained by other techniques. The values of D were also calculated by molecular-dynamics simulation and they qualitatively reproduce the behavior of D.
Imaging photon-initiated reactions: A study of the Cl(P3∕22)+CH4→HCl+CH3 reaction
Authors: Bass M. J. , Brouard M. , Cireasa R. , Clark A. P. , Vallance C.
Published: August 2005

The hydrogen or deuterium atom abstraction reactions between Cl(P3∕22) and methane, or its deuterated analogues CD4 and CH2D2, have been studied at mean collision energies around 0.34 eV. The experiments were performed in a coexpansion of molecular chlorine and methane in helium, with the atomic Cl reactants generated by polarized laser photodissociation of Cl2 at 308 nm. The Cl-atom reactants and the methyl radical products were detected using (2+1) resonantly enhanced multiphoton ionization, coupled with velocity-map ion imaging. Analysis of the ion images reveals that in single-beam experiments of this type, careful consideration must be given to the spread of reagent velocities and collision energies. Using the reactions of Cl with CH4, CD4, and CH2D2, as examples, it is shown that the data can be fitted well if the reagent motion is correctly described, and the angular scattering distributions can be obtained with confidence. New evidence is also provided that the CD3 radicals from the Cl+CD4 reaction possess significant rotational alignment under the conditions of the present study. The results are compared with previous experimental and theoretical works, where these are available.
Conduction mechanisms and charge storage in Si-nanocrystals metal-oxide-semiconductor memory devices studied with conducting atomic force microscopy
Authors: Porti M. , Avidano M. , Nafría M. , Aymerich X. , Carreras J. , Garrido B.
Published: August 2005

In this work, we demonstrate that conductive atomic force microscopy (C-AFM) is a very powerful tool to investigate, at the nanoscale, metal-oxide-semiconductor structures with silicon nanocrystals (Si-nc) embedded in the gate oxide as memory devices. The high lateral resolution of this technique allows us to study extremely small areas (∼300nm2) and, therefore, the electrical properties of a reduced number of Si-nc. C-AFM experiments have demonstrated that Si-nc enhance the gate oxide electrical conduction due to trap-assisted tunneling. On the other hand, Si-nc can act as trapping centers. The amount of charge stored in Si-nc has been estimated through the change induced in the barrier height measured from the I-V characteristics. The results show that only ∼20% of the Si-nc are charged, demonstrating that the electrical behavior at the nanoscale is consistent with the macroscopic characterization.
Temperature effects on luminescence properties of Cr3+ ions in alkali gallium silicate nanostructured media
Authors: Lipinska-Kalita Kristina E. , Krol Denise M. , Hemley Russell J. , Kalita Patricia E. , Gobin Cedric L. , Ohki Yoshimichi
Published: August 2005

We have investigated the optical properties of Cr3+ ions in an alkali gallium silicate glass system and in two glass-based nanocomposites with nucleated β-Ga2O3 nanocrystals. The nucleation and growth of the nanocrystalline phase in the host glass matrix were monitored by Raman scattering spectroscopy and angle-dispersive x-ray diffraction. A broadband luminescence, associated with the T24-A24 transition from the weak crystal field of octahedral Cr3+ sites, dominated the emission of the precursor as-quenched glass. The luminescence spectra of the synthesized glass-ceramic nanocomposites revealed a crystal-like E2-A24 strong emission and indicated that the major fraction of Cr3+ ions was located within the nanocrystalline environment. The variable-temperature studies of the nanocomposites demonstrated that the fluorescence of Cr3+ ions can be transformed from sharp R lines of the E2-A24 transition to a combination of R lines and of the broad band of the T24-A24 transition. We propose a simple distribution model where the major part of Cr3+ ions is located in the nanocrystalline phase of the glass-ceramic composites in the octahedral environment, substituting the gallium atoms in the β-Ga2O3 crystal structure. The developed nanocrystalline glass-ceramics are a promising class of Cr3+-doped oxide glass-based optically active composite materials.