bluuebunny/crossref_metadata_2025_split huggingface dataset:
Satellite Observations of Seasonal and Interannual Changes of Sea Level and Currents over the Scotian Slope
Authors: Han Guoqi 
Published: May 2007

Abstract
Seasonal and interannual sea level and current variations over the Scotian slope are examined using 10 years of Ocean Topography Experiment (TOPEX)/Poseidon (T/P) satellite altimeter data. Geostrophic surface current anomalies normal to ground tracks are derived from the along-track gradients of sea level anomalies. The altimetric current anomalies are combined with a climatological mean circulation field of a finite-element model to construct nominal absolute currents. The seasonal mean results indicate that the sea level is highest in late summer and lowest in late winter and that the surface slope circulation is strong in winter/autumn and weaker in summer/spring. The total transport associated with the westward shelf-edge current and with the eastward slope current, calculated by combining the T/P data with a climatological seasonal mean density field, reveals a substantial seasonal change dominated by the barotropic component. The present analysis reveals prominent interannual changes of the sea level and current anomalies for the study period. The sea level was lowest in 1996/97, when the Gulf Stream was in its most southern position. The mean winter circulation over the Scotian slope was strongest (up to 30 cm s−1 in both the southwestward shelf-edge current and northeastward slope current) in 1998 and weakest (weaker and broader shelf-edge current) in 1996, which may be related to the fluctuation of the equatorward Labrador Current strength and of the Gulf Stream north–south position. The study also suggests that the root-mean-square current magnitude is positively correlated with the occurrence of the Gulf Stream warm-core rings (WCRs) on the interannual scale, while WCR yearly mean kinematic properties seem to have small variations.
Ventilation and Transformation of Labrador Sea Water and Its Rapid Export in the Deep Labrador Current
Authors: Brandt Peter , Funk Andreas , Czeschel Lars , Eden Carsten , Böning Claus W. 
Published: May 2007

Abstract
A model of the subpolar North Atlantic Ocean is used to study different aspects of ventilation and water mass transformation during a year with moderate convection intensity in the Labrador Sea. The model realistically describes the salient features of the observed hydrographic structure and current system, including boundary currents and recirculations. Ventilation and transformation rates are defined and compared. The transformation rate of Labrador Sea Water (LSW), defined in analogy to several observational studies, is 6.3 Sv (Sv ≡ 106 m3 s−1) in the model. Using an idealized ventilation tracer, mimicking analyses based on chlorofluorocarbon inventories, an LSW ventilation rate of 10 Sv is found. Differences between both rates are particularly significant for those water masses that are partially transformed into denser water masses during winter. The main export route of the ventilated LSW is the deep Labrador Current (LC). Backward calculation of particle trajectories demonstrates that about one-half of the LSW leaving the Labrador Sea within the deep LC originates in the mixed layer during that same year. Near the offshore flank of the deep LC at about 55°W, the transformation of LSW begins in January and is at a maximum in February/March. While the export of transformed LSW out of the central Labrador Sea continues for several months, LSW generated near the boundary current is exported more rapidly, with maximum transport rates during March/April within the deep LC.
Effect of Sea Surface Temperature–Wind Stress Coupling on Baroclinic Instability in the Ocean
Authors: Spall Michael A. 
Published: May 2007

Abstract
The impact of the observed relationship between sea surface temperature and surface wind stress on baroclinic instability in the ocean is explored using linear theory and a nonlinear model. A simple parameterization of the influence of sea surface temperature on wind stress is used to derive a surface boundary condition for the vertical velocity at the base of the oceanic Ekman layer. This boundary condition is applied to the classic linear, quasigeostrophic stability problem for a uniformly sheared flow originally studied by Eady in the 1940s. The results demonstrate that for a wind directed from warm water toward cold water, the coupling acts to enhance the growth rate, and increase the wavelength, of the most unstable wave. Winds in the opposite sense reduce the growth rate and decrease the wavelength of the most unstable wave. For representative coupling strengths, the change in growth rate can be as large as ±O(50%). This effect is largest for shallow, strongly stratified, low-latitude flows.
L'explication politique africaniste et l'histoire: à propos de “l'historicité” des sociétés africaines
Authors: Onana Janvier 
Published: May 2007

English The article explores in tandem the epistemological suppositions that inform the problematics as they are usually formulated in terms of the historicity characteristic of African societies and the inherent methodological corollaries. The aim of this discussion, intended to be constructive, is to highlight some of the conceptual ambiguities and theoretical aporias that continue to insinuate themselves into the most common, including the best-established, theories, with the result that the distance often urged with respect to what are rightly held to be opposing schools of thought (especially developmentalism) seems in certain respects to be more a matter of lip-service than of actual practice. French L'article explore conjointement les présupposés épistémologiques qui informent les problématisations habituelles en termes d'historicité propre des sociétés africaines et les corrélats méthodologiques qui leur sont inhérents. L'enjeu de cette discussion qui se veut constructive est de relever quelques unes des équivoques conceptuelles et apories théoriques qui continuent de s'insinuer dans les élaborations théoriques les plus courantes, y compris, les mieux établies, au point que la distance souvent revendiquée d'avec les modes de pensée justement tenus en opposition (tout particulièrement le développementalisme) semble à certains égards davantage énoncée que réellement pratiquée.
Diversifying selection and host adaptation in two endosymbiont genomes
Authors: Brownlie Jeremy C , Adamski Marcin , Slatko Barton , McGraw Elizabeth A 
Published: May 2007

AbstractBackgroundThe endosymbiontWolbachia pipientisinfects a broad range of arthropod and filarial nematode hosts. These diverse associations form an attractive model for understanding host:symbiont coevolution.Wolbachia's ubiquity and ability to dramatically alter host reproductive biology also form the foundation of research strategies aimed at controlling insect pests and vector-borne disease. TheWolbachiastrains that infect nematodes are phylogenetically distinct, strictly vertically transmitted, and required by their hosts for growth and reproduction. Insects in contrast form more fluid associations withWolbachia. In these taxa, host populations are most often polymorphic for infection, horizontal transmission occurs between distantly related hosts, and direct fitness effects on hosts are mild. Despite extensive interest in theWolbachiasystem for many years, relatively little is known about the molecular mechanisms that mediate its varied interactions with different hosts. We have compared the genomes of theWolbachiathat infectDrosophila melanogaster,wMel and the nematodeBrugia malayi,wBm to that of an outgroupAnaplasma marginaleto identify genes that have experienced diversifying selection in theWolbachialineages. The goal of the study was to identify likely molecular mechanisms of the symbiosis and to understand the nature of the diverse association across different hosts.ResultsThe prevalence of selection was far greater inwMel thanwBm. Genes contributing to DNA metabolism, cofactor biosynthesis, and secretion were positively selected in both lineages. InwMel there was a greater emphasis on DNA repair, cell division, protein stability, and cell envelope synthesis.ConclusionSecretion pathways and outer surface protein encoding genes are highly affected by selection in keeping with host:parasite theory. If evidence of selection on various cofactor molecules reflects possible provisioning, then both insect as well as nematodeWolbachiamay be providing substances to hosts. Selection on cell envelope synthesis, DNA replication and repair machinery, heat shock, and two component switching suggest strategies insectWolbachiamay employ to cope with diverse host and intra-host environments.
X-ray sequence and crystal structure of luffaculin 1, a novel type 1 ribosome-inactivating protein
Authors: Hou Xiaomin , Chen Minghuang , Chen Liqing , Meehan Edward J , Xie Jieming , Huang Mingdong 
Published: May 2007

Abstract

Background
Protein sequence can be obtained through Edman degradation, mass spectrometry, or cDNA sequencing. High resolution X-ray crystallography can also be used to derive protein sequence information, but faces the difficulty in distinguishing the Asp/Asn, Glu/Gln, and Val/Thr pairs. Luffaculin 1 is a new type 1 ribosome-inactivating protein (RIP) isolated from the seeds of Luffa acutangula. Besides rRNA N-glycosidase activity, luffaculin 1 also demonstrates activities including inhibiting tumor cells' proliferation and inducing tumor cells' differentiation.

Results
The crystal structure of luffaculin 1 was determined at 1.4 Å resolution. Its amino-acid sequence was derived from this high resolution structure using the following criteria: 1) high resolution electron density; 2) comparison of electron density between two molecules that exist in the same crystal; 3) evaluation of the chemical environment of residues to break down the sequence assignment ambiguity in residue pairs Glu/Gln, Asp/Asn, and Val/Thr; 4) comparison with sequences of the homologous proteins. Using the criteria 1 and 2, 66% of the residues can be assigned. By incorporating with criterion 3, 86% of the residues were assigned, suggesting the effectiveness of chemical environment evaluation in breaking down residue ambiguity. In total, 94% of the luffaculin 1 sequence was assigned with high confidence using this improved X-ray sequencing strategy. Two N-acetylglucosamine moieties, linked respectively to the residues Asn77 and Asn84, can be identified in the structure. Residues Tyr70, Tyr110, Glu159 and Arg162 define the active site of luffaculin 1 as an RNA N-glycosidase.

Conclusion
X-ray sequencing method can be effective to derive sequence information of proteins. The evaluation of the chemical environment of residues is a useful method to break down the assignment ambiguity in Glu/Gln, Asp/Asn, and Val/Thr pairs. The sequence and the crystal structure confirm that luffaculin 1 is a new type 1 RIP.
Protective role of fish oil (Maxepa) on early events of rat mammary carcinogenesis by modulation of DNA-protein crosslinks, cell proliferation and p53 expression
Authors: Manna Sangita , Chakraborty Tridib , Damodaran Suresh , Samanta Kartick , Rana Basabi , Chatterjee Malay 
Published: May 2007

Abstract

Background
Fish oil is known to protect from many types of cancers of the colon, liver, breast, prostate and lung [1–3]. The objective of the present study was to evaluate the role of fish oil [Maxepa, supplemented at a dose of 0.5 ml is equivalent to 90 mg eicosapentaenoic acid (EPA) and 60 mg docosahexaenoic acid (DHA)] on cell proliferation, expression of p53 tumor suppressor protein and DNA protein crosslinks (DPCs) in a defined model of chemical rat mammary carcinogenesis. Mammary carcinogenesis was initiated by a single, intravenous (i.v.) tail vein injection of 7,12 dimethylbenz(α)anthracene (DMBA) at a dose of 5 mg DMBA/2 ml corn oil/kg body weight in female Sprague-Dawley rats at 7 weeks of age. Fish oil supplementation was started daily, 2 weeks prior to DMBA injection and continued for 24 (31 weeks of animal age) weeks and 35 (42 weeks of animal age) weeks of post DMBA injection, for histopathological and immunohistochemical and for morphological studies, respectively.

Results
Our results indicate the chemopreventive effect of fish oil (Maxepa) on DMBA-induced rat mammary carcinogenesis. Administration of fish oil further showed a prominent reduction of cell proliferation (24.34%, P = 0.001); DPCs (25%, P < 0.001) and an increased expression of p53 protein (4.636 ± 0.19, P < 0.001) in preneoplastic mammary tissue when compared to carcinogen control counterpart. Histopathological and morphological analyses were carried out as end-point biomarkers.

Conclusion
Our study thus provides evidence for the anticarcinogenic effect of fish oil (Maxepa) in limiting mammary preneoplasia in Sprague-Dawley rats.
Outcome of life-threatening malaria in African children requiring endotracheal intubation
Authors: Gérardin Patrick , Rogier Christophe , Ka Amadou S , Jouvencel Philippe , Diatta Bakary , Imbert Patrick 
Published: May 2007

Abstract

Background
Little is known about children undergoing critical care for malaria. The purpose of this survey was to evaluate the outcome in African children requiring endotracheal intubation for life-threatening malaria.

Methods
All children with a primary diagnosis of severe malaria (2000 WHO definition) requiring endotracheal intubation, hospitalised over a five-year period, within a tertiary-care hospital in Dakar, Senegal, were enrolled in a retrospective cohort study.

Results
83 consecutive patients were included (median PRISM h24 score: 14; IQR: 10–19, multiple organ dysfunctions: 91.5%). The median duration of ventilation was 36 hrs (IQR: 4–72). Indications for intubation were deep coma (Glasgow score ≤7, n = 16), overt cortical or diencephalic injury, i.e, status epilepticus/decorticate posturing (n = 20), severe brainstem involvement, i.e., decerebrate posturing/opisthotonus (n = 15), shock (n = 15), cardiac arrest (n = 13) or acute lung injury (ALI) (PaO2/FiO2 <300 Torr, n = 4). Death occurred in 50 cases (case fatality rate (CFR), 60%) and was associated with multiple organ dysfunctions (median PELODh24 scores: 12.5 among non-survivors versus 11 among survivors, p = 0.02). Median PRISMh24 score was significantly lower when testing deep coma against other indications (10 vs 15, p < 0.001), ditto for PELODh24 score (2.5 vs 13, p = 0.02). Multivariate analysis identified deep coma as having a better outcome than other indications (CFR, 12.5% vs 40.0 to 93.3%, p < 0.0001). Decerebrate posturing/opisthotonus (CFR 73.3%, adjusted relative risk (aRR) 10.7, 95% CI 2.3–49.5) were associated with a far worse prognosis than status epilepticus/decorticate posturing (CFR 40.0%, aRR 5.7, 95% CI 1.2–27.1). Thrombocytopaenia (platelet counts <100,000/mm3) was associated with death (aRR 2.6, 95% CI 1.2–5.8) and second-line anticonvulsant use (clonazepam or thiopental) with survival (aRR 0.4, 95% CI 0.2–0.9). Complications, mostly nosocomial infections (n = 20), ALI/ARDS (n = 9) or sub-glottic stenosis (n = 3), had no significant prognostic value.

Conclusion
In this study, the outcome of children requiring intubation for malaria depends more on clinical presentation and progression towards organ failures than on critical care complications per se. In sub-Saharan Africa, mechanical ventilation for life-threatening childhood malaria is feasible, but seems unlikely to dramatically improve the prognosis.
Lymphocytic thyroiditis – is cytological grading significant? A correlation of grades with clinical, biochemical, ultrasonographic and radionuclide parameters
Authors: Bhatia Alka , Rajwanshi Arvind , Dash Radharaman J , Mittal Bhagwant R , Saxena Akshay K 
Published: May 2007

BackgroundClinical, biochemical, ultrasonographic, radionuclide and cytomorphological observations in Lymphocytic thyroiditis (LT), to define the cytological grading criteria on smears and correlation of grades with above parameters.

MethodsThis prospective study was conducted on 76 patients attending the Fine needle aspiration cytology clinic of a tertiary care institute in North India. The various parameters like patients’ clinical presentation, thyroid antimicrosomal antibodies, hormonal profiles, radionuclide thyroid scan and thyroid ultrasound were studied. Fine needle aspiration of thyroid gland and grading of thyroiditis was done on smears. The grades were correlated with above parameters and the correlation indices were evaluated statistically.

ResultsMost of the patients were females (70, 92.11%) who presented with a diffuse goiter (68, 89.47%). Hypothyroid features (56, 73.68%) and elevated TSH (75, 98.68%) were common, but radioiodide uptake was low or normal in majority of patients. Thyroid antimicrosomal antibody was elevated in 46/70 (65.71%) patients. Cytomorphology in fine needle aspirates was diagnostic of lymphocytic thyroiditis in 75 (98.68%) patients. Most of them had grade I/II disease by cytology. No correlation was observed between grades of cytomorphology and clinical, biochemical, ultrasonographic and radionuclide parameters.

ConclusionDespite the availability of several tests for diagnosis of LT, FNAC remains the gold standard. The grades of thyroiditis at cytology however do not correlate with clinical, biochemical, radionuclide and ultrasonographic parameters.
Fractal time series analysis of postural stability in elderly and control subjects
Authors: Amoud Hassan , Abadi Mohamed , Hewson David J , Michel-Pellegrino Valérie , Doussot Michel , Duchêne Jacques 
Published: May 2007

Abstract

Background
The study of balance using stabilogram analysis is of particular interest in the study of falls. Although simple statistical parameters derived from the stabilogram have been shown to predict risk of falls, such measures offer little insight into the underlying control mechanisms responsible for degradation in balance. In contrast, fractal and non-linear time-series analysis of stabilograms, such as estimations of the Hurst exponent (H), may provide information related to the underlying motor control strategies governing postural stability. In order to be adapted for a home-based follow-up of balance, such methods need to be robust, regardless of the experimental protocol, while producing time-series that are as short as possible. The present study compares two methods of calculating H: Detrended Fluctuation Analysis (DFA) and Stabilogram Diffusion Analysis (SDA) for elderly and control subjects, as well as evaluating the effect of recording duration.

Methods
Centre of pressure signals were obtained from 90 young adult subjects and 10 elderly subjects. Data were sampled at 100 Hz for 30 s, including stepping onto and off the force plate. Estimations of H were made using sliding windows of 10, 5, and 2.5 s durations, with windows slid forward in 1-s increments. Multivariate analysis of variance was used to test for the effect of time, age and estimation method on the Hurst exponent, while the intra-class correlation coefficient (ICC) was used as a measure of reliability.

Results
Both SDA and DFA methods were able to identify differences in postural stability between control and elderly subjects for time series as short as 5 s, with ICC values as high as 0.75 for DFA.

Conclusion
Both methods would be well-suited to non-invasive longitudinal assessment of balance. In addition, reliable estimations of H were obtained from time series as short as 5 s.
Towards the uniform distribution of null P values on Affymetrix microarrays
Authors: Fodor Anthony A , Tickle Timothy L , Richardson Christine 
Published: May 2007

AbstractMethods to control false-positive rates require that P values of genes that are not differentially expressed follow a uniform distribution. Commonly used microarray statistics can generate P values that do not meet this assumption. We show that poorly characterized variance, imperfect normalization, and cross-hybridization are among the many causes of this non-uniform distribution. We demonstrate a simple technique that produces P values that are close to uniform for nondifferentially expressed genes in control datasets.
Regulation of TLR4 signaling and the host interface with pathogens and danger: the role of RP105
Authors: Divanovic Senad , Trompette Aurelien , Petiniot Lisa K , Allen Jessica L , Flick Leah M , Belkaid Yasmine , Madan Rajat , Haky Jennifer J , Karp Christopher L 
Published: May 2007

AbstractAs all immune responses have potential for damaging the host, tight regulation of such responses—in amplitude, space, time and character—is essential for maintaining health and homeostasis. It was thus inevitable that the initial wave of papers on the role of Toll-like receptors (TLRs), NOD-like receptors (NLRs) and RIG-I-like receptors (RLRs) in activating innate and adaptive immune responses would be followed by a second wave of reports focusing on the mechanisms responsible for restraining and modulating signaling by these receptors. This overview outlines current knowledge and controversies about the immunobiology of the RP105/MD-1 complex, a modulator of the most robustly signaling TLR, TLR4.
Lymphocyte function during hepatic ischemia/reperfusion injury
Authors: Caldwell Charles C , Tschoep Johannes , Lentsch Alex B 
Published: May 2007

AbstractThe liver is the primary organ affected by ischemia/reperfusion (I/R) injury after shock, surgical resection, or transplantation. The actions of myeloid leukocytes have been well studied and are thought to be the primary cells responsible for propagating the injury response. However, there is an emerging view that T lymphocytes can also regulate liver I/R-induced inflammation. Resident lymphocytes found within the liver include conventional αβ TCR cells as well as unconventional NK and γδ T cells. These lymphocytes can alter inflammation through the secretion of soluble mediators such as cytokines and chemokines or through cognate interactions in an antigen-dependent manner. Expression of these mediators will then result in the recruitment of more lymphocytes and neutrophils. There is evidence to suggest that T cell activation in the liver during I/R can be driven by antigenic or nonantigenic mechanisms. Finally, immune cells are exposed to different oxygen tensions, including hypoxia, as they migrate and function within tisues. The hypoxic environment during liver ischemia likely modulates T cell function, at least in part through the actions of hypoxia-inducible factor-1α. Further, this hypoxic environment leads to the increased concentration of extracellular adenosine, which is generally known to suppress T cell proinflammatory function. Altogether, the elucidation of T lymphocyte actions during liver I/R will likely allow for novel targets for therapeutic intervention.