bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of nucleoside analog‐interferon sequential therapy on patients with acute exacerbation of chronic hepatitis B
Authors: Okuse Chiaki , Yotsuyanagi Hiroshi , Yamada Norie , Okamoto Masaru , Ikeda Hiroki , Kobayashi Minoru , Fukuda Yasunobu , Takahashi Hideaki , Nagase Yoshihiko , Suzuki Yuka , Matsunaga Kotaro , Ishii Toshiya , Matsumoto Nobuyuki , Koike Kazuhiko , Suzuki Michihiro , Itoh Fumio
Published: April 2010

Aim:  Nucleoside analog (NA)‐interferon (IFN) sequential therapy may enable the long‐term control of chronic hepatitis B (CHB) and the withdrawal of the nucleoside analog. We evaluated the efficacy of NA‐IFN sequential therapy for acute exacerbation of CHB.

Methods:  A total of 12 patients with acute exacerbation of CHB, nine of whom were positive for hepatitis B e antigen (HBeAg), were enrolled in this study. All the patients were treated with lamivudine 100 mg/day alone for 20 weeks, then with both IFN‐α 6 megaunits three times per week and lamivudine for 4 weeks, and lastly, with IFN‐α alone for 20 weeks. Patients whose serum alanine aminotransferase (ALT) level was normalized, whose serum hepatitis B virus (HBV) DNA level decreased to less than 5 log copies/mL, and HBeAg level was absent 24 weeks after the end of treatment were defined as having sustained virological response (SVR). The other patients were defined as having no response (NR).

Results:  Four out of nine (44.4%) HBeAg‐positive and all three HBeAg‐negative patients achieved SVR. The levels of serum alanine aminotransferase (ALT), HBV DNA and HBV core‐related antigen were similar between SVR and NR patients at baseline. Three of four patients (75.0%) whose serum HBeAg became negative at the end of treatment achieved SVR, while one of five (20.0%) whose serum HBeAg remained positive achieved SVR.

Conclusion:  NA‐IFN sequential therapy for patients with acute exacerbation of CHB enables the withdrawal of treatment and is particularly effective for patients whose serum HBeAg has become undetectable by the end of the IFN treatment.
The use of CT and CT arthrography in diagnosing equine stifle injury in a Rheinlander gelding
Authors: CRIJNS C. P. , GIELEN I. M. V. L. , Van BREE H. J. J. , BERGMAN E. H. J.
Published: April 2010

A 5‐year‐old Rheinlander gelding was evaluated for left hindlimb stifle lameness. The lameness was localised to the stifle, but source of the lameness was not specifically diagnosed from the physical, radiographic and ultrasonographic examinations. Computed tomography (CT) and CT arthrography were therefore used for further investigation since these imaging techniques image bony structures, cartilage and soft tissues. This examination showed multiple lesions in the stifle: an osteochondrosis dissecans like lesion of the medial femoral condyle, bony fragments, cartilage trauma and caudal cruciate ligament injury. The prognosis for continuing use as a sports horse was regarded as unfavourable. Therefore, the horse was subjected to euthanasia. All CT findings were confirmed by gross pathology.

The CT and CT arthrography examination in this case provided a diagnosis not achieved with other conventional imaging techniques.
Adult Science Learning in the Internet Era
Authors: Miller Jon D.
Published: April 2010

Abstract  This article outlines a different view of the changing nature of adult learning in the Internet era. The old model of learning—the warehouse—is being replaced by a “just‐in‐time” system of information acquisition. The NRC report focuses too heavily on finding missions for existing institutions and pays too little attention to the pervasive changes in information acquisition and adult learning in all areas. An analysis of existing data demonstrates the relative impact of formal and informal learning and points to opportunities for enhanced adult science learning in the future. In a just‐in‐time world, museums and similar informal learning institutions will need to be less dependent on their physical setting and more focused on learning as the end product. It will also be necessary to find a viable revenue model to support this emerging mission.
Creating, implementing, and sustaining an advanced optical spectroscopy laboratory course
Authors: Blue Jennifer , Bayram S. Burcin , Marcum S. Douglas
Published: April 2010

An upper-division laboratory course in atomic and molecular spectroscopy is described. Examples of outcomes that also benefit second-year physics laboratories and demonstrations in introductory courses are presented. The overarching goal that drove the development of the course was to assist students in understanding the fundamental connections between atomic and molecular spectra and the underlying structures. A selection of laboratory experiences supporting this goal, and the equipment and techniques necessary to provide them, are outlined.
Rapid Diversification of Cell Signaling Phenotypes by Modular Domain Recombination
Authors: Peisajovich Sergio G. , Garbarino Joan E. , Wei Ping , Lim Wendell A.
Published: April 2010

Domain Swaps to Phenotype Shifts

For natural selection there must be mechanisms that create phenotypic diversity, presumably from relatively simple molecular changes in an organism.

Peisajovich
et al.

(p.
368
) tested the extent to which changes in phenotype can occur by systematic swapping of protein domains in the components of the biochemical signaling pathway that controls mating in yeast. Such changes decreased or increased responsiveness to yeast mating pheromone, and some translated into changes in mating efficiency. The authors propose that shuffling of modular protein domains may be an important source of phenotypic diversity in evolution and may also be a useful strategy for the engineering of biological systems.
Oxoboryl Complexes: Boron−Oxygen Triple Bonds Stabilized in the Coordination Sphere of Platinum
Authors: Braunschweig Holger , Radacki Krzysztof , Schneider Achim
Published: April 2010

One B, One O

Boron has a tendency to share electrons with multiple different atoms, hence exhibiting a rich cluster chemistry, in contrast to the more traditional two-center, two-electron bonds prevailing in the compounds of most other light elements.

Braunschweig
et al.

(p.
345
) have coaxed boron into a more confined setting and made a boron analog of carbon monoxide as a triply bonded BO anion that was stabilized by coordination to a platinum center. The product formed easily in room temperature solution from a precursor substituted with a silyl group on the oxygen and a bromide on the boron and exhibited surprising stability toward heating and photolysis. The BO anion is a fundamental binary material, isoelectronic with CO, CN-, and NO+, which have been the key binary ligands in organometallic and coordination chemistry for more than 50 years.
Evolution of an Expanded Sex-Determining Locus in
Volvox
Authors: Ferris Patrick , Olson Bradley J. S. C. , De Hoff Peter L. , Douglass Stephen , Casero David , Prochnik Simon , Geng Sa , Rai Rhitu , Grimwood Jane , Schmutz Jeremy , Nishii Ichiro , Hamaji Takashi , Nozaki Hisayoshi , Pellegrini Matteo , Umen James G.
Published: April 2010

Revealing
Volvox

Female and male gametes of the green alga,
Volvox
, significantly differ in size. Those of
Chlamydomonas
, another green algae from a lineage that separated from
Volvox
some 200 million years ago, are the same size. We know sex in
Chlamydomonas
is governed by a sex-determining locus called
MT
. In a detailed comparison of the
MT
loci of
Volvox
and
Chlamydomonas
,

Ferris
et al.

(p.
351
) found that although
MT
has retained some similarity in gene order, its composition has greatly changed between the two species. In
Volvox
, new genes have been coopted into this locus and show sex-specific expression.
Biotech Crops Good for Farmers and Environment, Academy Finds
Authors: Stokstad Erik
Published: April 2010

Fourteen years after genetically engineered crops began to take off in the United States, the overall benefits to farmers are clear, according to a new report from the National Research Council.
Exploring New Routes for Neuroprotective Drug Development in Traumatic Brain Injury
Authors: Janowitz T. , Menon D. K.
Published: April 2010

The methods and devices used in the clinical management of neurological patients can provide data to facilitate progress in treating brain trauma.
Challenges in Using Stem Cells for Cardiac Repair
Authors: Mummery Christine L. , Davis Richard P. , Krieger Jose E.
Published: April 2010

Stem cell–derived cardiomyocytes offer promise for treating
damage caused by heart attacks, but through different mechanisms than
originally believed.
Rx: A Little Sunshine Without Sunscreen?
Authors: Ahmad Shama
Published: April 2010

Low vitamin D levels correlate with reduced lung function, airway constrictions, and decreased response to therapeutic steroids in asthma patients.
Epidemiologic Study of Human Influenza Virus Infection in South Korea from 1999 to 2007: Origin and Evolution of A/Fujian/411/2002-Like Strains
Authors: Kang Seokha , Yang In Seok , Lee Joo-Yeon , Park Yiho , Oh Hee-Bok , Kang Chun , Kim Kyung Hyun
Published: April 2010

Influenza epidemics arise through the accumulation of viral genetic changes, culminating in a novel antigenic type that is able to escape host immunity. Following an outbreak of the A/Fujian/411/2002-like strains in Asia, including China, Japan, and South Korea, in 2002, Australia and New Zealand experienced substantial outbreaks of the same strains in 2003, and subsequently worldwide outbreaks occurred in the 2003-2004 season. The emergence of A/Fujian/411/2002-like strains coincided with a higher level of influenza-like illness in South Korea than what is seen at the peak of a normal season, and there was at least a year's difference between South Korea and the United States. Genetic evolution of human influenza A/H3N2 viruses was monitored by sequence analysis of hemagglutinin (HA) genes collected in Asia, including 269 (164 new) HA genes isolated in South Korea from 1999 to 2007. The Fujian-like influenza strains were disseminated with rapid sequence variation across the antigenic sites of the HA1 domain, which sharply distinguished between the A/Moscow/10/1999-like and A/Fujian/411/2002-like strains. This fast variation, equivalent to approximately 10 amino acid changes within a year, occurred in Asia and would be the main cause of the disappearance of the reassortants, although the reassortant and nonreassortant Fujian-like strains circulated simultaneously in Asia.
Rapid Diagnosis of Old World Leishmaniasis by High-Resolution Melting Analysis of the 7SL RNA Gene
Authors: Nasereddin Abedelmajeed , Jaffe Charles L.
Published: April 2010

High-resolution melt analysis PCR (HRM PCR) for diagnosis of Old World
Leishmania
was developed using the 7SL RNA gene. Cutaneous leishmaniasis samples were analyzed. Sensitivity and specificity of HRM PCR were significantly better (
P
< 0.001) than those of internal transcribed spacer 1 PCR and similar to those of kinetoplast DNA PCR.
Diagnostic Value of PCR Analysis of Bacteria and Fungi from Blood in Empiric-Therapy-Resistant Febrile Neutropenia
Authors: Nakamura Akiko , Sugimoto Yuka , Ohishi Kohshi , Sugawara Yumiko , Fujieda Atsushi , Monma Fumihiko , Suzuki Kei , Masuya Masahiro , Nakase Kazunori , Matsushima Yoshiko , Wada Hideo , Katayama Naoyuki , Nobori Tsutomu
Published: April 2010

This study aimed to assess the clinical utility of PCR for the analysis of bacteria and fungi from blood for the management of febrile neutropenic patients with hematologic malignancies. Using a PCR system able to detect a broad range of bacteria and fungi, we conducted a prospective pilot study of periodic analyses of blood from patients following intensive chemotherapy. When fever occurred, it was treated with empirical antibiotic therapy, basically without knowledge of the PCR results. In 23 febrile episodes during the neutropenic period, bacteria were detected by PCR in 11 cases, while the same species were identified by blood culture in 3 cases. In 10 out of 11 PCR-positive cases, fever could be managed by empirical therapy. In the empirical-therapy-resistant case, the identification ofStenotrophomonas maltophiliaby PCR led to improvement of fever. No fungi were detected by PCR in febrile cases, whileAspergillus fumigatuswas detected in one afebrile patient, several days before a clinical diagnosis was made. In subsequent sporadic PCR analyses in 15 cases of febrile neutropenia, bacteria were detected by both PCR and blood culture in 7 cases and by PCR alone in 6. Fungi were not detected. While fever was improved by empirical therapy in 12 out of the 13 PCR-positive cases, the identification ofPseudomonas aeruginosaby PCR in one therapy-resistant case contributed to the successful treatment of persistent fever. Our results indicate that PCR analysis of bacteria from blood provides essential information for managing empirical-therapy-resistant febrile neutropenia.
Natural Occurrence of Horizontal Transfer ofMycobacterium avium- Specific Insertion Sequence IS1245toMycobacterium kansasii
Authors: da Silva Rabello Michelle Christiane , de Oliveira Rosangela Siqueira , Silva Rosa Maria , Leao Sylvia Cardoso
Published: April 2010

Mycobacterium kansasiicarrying IS1245, a highly prevalent insertion sequence amongMycobacterium aviumisolates, was detected in a mixed culture ofM. aviumandM. kansasii. The insertion sequence was stable and able to transpose by a replicative mechanism inM. kansasii. These findings may have significant implications for molecular diagnosis and treatment outcome.
Epidemiology and Genotype Analysis of Emerging Sapovirus-Associated Infections across Europe
Authors: Svraka Sanela , Vennema Harry , van der Veer Bas , Hedlund Kjell-Olof , Thorhagen Margareta , Siebenga Joukje , Duizer Erwin , Koopmans Marion
Published: April 2010

Sapoviruses (SaVs) belong to theCaliciviridaefamily and can cause gastroenteritis in humans and swine. Despite extensive testing, human sapoviruses have been found only in sporadic cases and in one mixed outbreak in children between 1994 and 2007 in the Netherlands. Here we describe a change in sapovirus epidemiology in the Netherlands resulting in sapovirus outbreaks and infections in adults. From November 2007 to January 2009, 478 outbreaks of acute gastroenteritis were reported to the National Institute for Public Health and the Environment in the Netherlands as a part of ongoing surveillance. Sapoviruses were found to be the most likely cause of 19 outbreaks (4%). During the same 2-year period, sapovirus infections were reported in Sweden, Slovenia, and Hungary. In the Netherlands, further characterization of outbreak strains showed that 12 (63%) sapovirus outbreaks were caused by genotype I.2 viruses. Most patients were adults older than 60 years (range, 1 to 100 years). Phylogenetic analysis using all presently available SaV sequences showed high homology between genotype I.2 strains detected in different geographical regions (Sweden, Slovenia, Taiwan, Japan, and Russia) since 2007. These first reported outbreaks of sapovirus infections in adults in the Netherlands were remarkable. Detection of identical genotypes in many samples might suggest that these viruses have the same origin, and since the infection is spreading fast, the prevalence of sapovirus infection may be increasing. The incidence of sapovirus infections in these countries suggests that a substantial part of Europe is affected by this virus.
Host Factors Associated with the Sindbis Virus RNA-Dependent RNA Polymerase: Role for G3BP1 and G3BP2 in Virus Replication
Authors: Cristea Ileana M. , Rozjabek Heather , Molloy Kelly R. , Karki Sophiya , White Laura L. , Rice Charles M. , Rout Michael P. , Chait Brian T. , MacDonald Margaret R.
Published: April 2010

Sindbis virus (SINV) is the prototype member of the
Alphavirus
genus, whose members cause severe human diseases for which there is no specific treatment. To ascertain host factors important in the replication of the SINV RNA genome, we generated a SINV expressing nsP4, the viral RNA-dependent RNA polymerase, with an in-frame 3×Flag epitope tag. Proteomic analysis of nsP4-containing complexes isolated from cells infected with the tagged virus revealed 29 associated host proteins. Of these, 10 proteins were associated only at a later time of infection (12 h), 14 were associated both early and late, and five were isolated only at the earlier time (6 h postinfection). These results demonstrate the dynamic nature of the virus-host interaction that occurs over the course of infection and suggest that different host proteins may be required for the multiple functions carried out by nsP4. Two related proteins found in association with nsP4 at both times of infection, GTPase-activating protein (SH3 domain) binding protein 1 (G3BP1) and G3BP2 were also previously identified as associated with SINV nsP2 and nsP3. We demonstrate a likely overlapping role for these host factors in limiting SINV replication events. The present study also identifies 10 host factors associated with nsP4 6 h after infection that were not found to be associated with nsP2 or nsP3. These factors are candidates for playing important roles in the RNA replication process. Identifying host factors essential for replication should lead to new strategies to interrupt alphavirus replication.
Radiometric Ages of Granitic Rocks, Cape Breton Island, Nova Scotia
Authors: Cormier Randall F.
Published: April 2010

Rubidium–strontium whole-rock and mineral ages of granitic rocks from fourteen localities on Cape Breton Island have been measured. The ages cluster about a mean value of about 560 m.y. and indicate that most of the granitic rocks on the island have primary ages that are close to the Cambrian–Precambrian (Hadrynian) boundary. Some of the granitic rocks, particularly in the northern highlands, may have considerably younger, Siluro–Devonian (Acadian?), primary ages. Evidence is presented suggesting that simple biotite ages are not always reliable for the measurement of primary ages of granitic rocks. It. is suggested that, the granitic rocks having primary ages close to the Cambrian-Precambrian boundary be referred to a hitherto generally unrecognized episode of granitic intrusion, the Bretonian.
Palynological Zonation of Cretaceous and Early Tertiary Rocks of the Bonnet Plume Formation Northeastern Yukon, Canada
Authors: Rouse Glenn E. , Srivastava Satish K.
Published: April 2010

Siltstones, shales, and coals from sections of the Bonnet Plume Formation at the confluence of the Peel and Wind Rivers were analyzed for plant microfossils. Assemblages recovered indicate the presence of 3 pollen-biostratigraphic zones belonging to 3 distinct time intervals. The oldest (zone 1) containing such species as Appendicisporites trichacanthus trichacanthus, A. matesovae, A. erdtmannii, Foveosporites sp., Cicatricosisporites perforatus, and Retitricolpites vulgaris, is considered to be mid-late Albian. In general, it is correlative to parts of the Mannville Group of Alberta, the Potomac of the Atlantic seaboard, and Albian assemblages from Siberia. The middle assemblage (zone 2) is Maastrichtian, containing such diagnostic palynomorphs as Aquilapollenites, Mancicorpus, Cranwellia, and Wodehousea. The third zone is considered to be Paleocene, with such characteristic species as Betulaceoipollenites infrequens, Fraxinoipollenites variabilis, Myricipites dubius, Extratriporopollenites sp., Paraalnipollenites confusus, and Pistillipollenites mcgregorii. The stratigraphic, time, and spatial relationships of the 3 zone-units are illustrated and discussed, and a general reconstruction of the paleoecology is attempted. Probable relationships to strata in other regions of North America and eastern Asia are also considered.
Sheeted Dikes and Brecciated Dike Rocks Within Transported Igneous Complexes Bay of Islands, Western Newfoundland
Authors: Williams Harold , Malpas John
Published: April 2010

Sheeted dikes and brecciated dike rocks occur stratigraphically between underlying gabbros and overlying pillowed lavas of the Bay of Islands Complex at Blow-Me-Down Mountain and North Arm Mountain. The dikes trend northwesterly, dip steeply southwest or northeast and are approximately at right angles to the trend of the contacts between major rock units that comprise the complex. Similar dikes and dike breccias occur within other transported slices farther west (Little Port Complex) where they separate foliated gabbros, amphibolites, and sodic granites from adjoining relatively undeformed pillowed lavas.The dikes are metamorphosed but relict textures are everywhere preserved. Actinolite, epidote, chlorite, and zoisite are the commonest metamorphic minerals. Prehnite is abundant in some places and pumpellyite and other minerals of the zeolite facies assemblage are known locally in nearby volcanic rocks. The metamorphism within the dikes and overlying volcanic rocks can be related to depth of burial or geothermal gradient, and it is interpreted as an early hydration of the rocks that occurred in their place of formation at an Early Paleozoic spreading oceanic ridge.Brecciated dike rocks are much more common in places than sheeted dikes and cover an area of approximately 40 mi2 (64 km2) atop North Arm Mountain. The brecciation is chiefly localized in the dike horizon of the Bay of Islands Complex but it locally affects underlying gabbros and overlying volcanic rocks. In the Little Port Complex, the brecciation also affects foliated gabbros, amphibolites, and sodic granites. There is nothing to suggest that the brecciation is the result of brittle deformation. Rather the textures are comparable to those developed in igneous rocks through gas action or fluidization. The brecciation largely predates metamorphism in the dike rocks and it is therefore also interpreted as a feature related to Early Paleozoic plate accretion.The Bay of Islands Complex is a typical ophiolite suite. Recognition and definition of the Little Port Complex as a polygenetic assemblage distinct from the Bay of Islands Complex reconciles the contrasting structural styles between the two and removes a major obstacle to the interpretation of the Bay of Islands Complex as oceanic crust. The Twillingate Granite in Notre Dame Bay of northeast Newfoundland is thought to provide a direct analogy to deformed rocks of the Little Port Complex and all are interpreted as older deformed crustal remnants surrounded by ophiolitic rocks related to an Early Paleozoic ocean spreading episode.
Silurian stratigraphy of the Hudson Bay Lowland in Quebec
Authors: Larsson Sven Y. , Stearn Colin W.
Published: April 2010

Carbonates of late Llandoverian to Ludlovian age, divided into the Severn River, Ekwan River, and Kenogami River formations, crop out in the drainage basin of the Harricana River. The Severn River Formation consists of a succession of alternating wackestone and packstone beds 17.5 m thick. The packstones are ascribed to storm events and carry a deeper water fauna than the wackestones. The Ekwan River Formation is divided into four units: a barren dolostone at the base, sandy wackestones and packstones with a coral fauna, another barren dolomudstone, and at the top a unit of argillaceous, nodular limestone rich in leperditid ostracods. The units are ascribed to shallow subtidal, intertidal, and supratidal environments. Three benthic assemblages, characterized by ostracods, corals, rhynchonellids, and the brachiopods Brachyprion and Dalejina, are distinguished in order of increasing depth. Two transgressive events in Llandoverian C4 and C6 times are marked by coral-rich units in the Severn River and Ekwan River formations.
Archean lamprophyre dykes and gold mineralization, Matheson, Ontario: the conjunction of LILE-enriched mafic magmas, deep crustal structures, and Au concentration
Authors: McNeil A. M. , Kerrich R.
Published: April 2010

At the Canadian Arrow deposit, Matheson, separate base- and precious-metal-bearing fracture arrays are associated with a trondhjemitic stock transected by lamprophyre dykes. Peripheral to the stock, high-Fe tholeiitic pillow basalts (Fe2O3 17.8 wt.%, TiO2 2.4 wt.%, Al2O3/TiO2 = 13.7), with interbedded felsic units, experienced amphibolite-facies hydrothermal or regional metamorphism and intense ductile deformation focussed within mylonite zones at the interflow horizons. The trondhjemite stock experienced pervasive reaction with marine water at temperatures that diminished to ≤ 150 °C: this was accompanied by conversion of plagioclase of igneous origin to albite, concomitant enrichment of sodium (Na2O = 8.32 ± 1.16 wt.%, 1σ), and shifts of albite up to δ18O = 14, with attendent, variably negative, quartz–albite fractionations.Galena-dominated veins were precipitated at 220–255 °C from hypersaline CaCl2–NaCl hydrothermal fluids with 22–34 equivalent wt.% NaCl, δ18O = +0.6 to +2.5; these were of evolved marine origin. Later gold-bearing quartz veins formed during hydraulic fracturing under conditions where Pfluid ≥ σ3 + tensile strength. Alteration in vein selvages involved the reaction of albite (δ18O = 14) to K-feldspar (δ18O = 11.3), with gains of Si, K, Rb, Ba, CO2, and S from the hydrothermal fluids and concomitant losses of Fe, Mg, and Na. Volume dilatations were up to +56%. Hydrothermal fluids implicated in this vein array were at 320 ± 20 °C, possessed low salinity, δ18OH2O = 8 ± 0.5, and underwent transient effervescence of CO2; they were of metamorphic or magmatic origin. Coexisting K-feldspar and hematite signify higher aqueous K+/H+ and more oxidizing conditions of deposition than that of most Archean lode gold deposits.Lamprophyre dykes containing trondhjemitic xenoliths were injected along two major subparallel fracture systems showing the same geometry and orientation as the gold-bearing veins. The dykes possess the low SiO2 (39.6 wt.%) and elevated incompatible (P, Th, Zr, Hf, LREE) and mafic (Cr, Ni, Co) trace elements characteristic of calc-alkaline lamprophyres; they are thought to be mantle derivatives. The dykes feature chondrite-normalized troughs at Ta–Nb and Ti. Fe–Mg carbonates in the least-altered lamprophyric dykes (δ13C = −2.8 ± 0.6) may have been derived from a magmatic carbonate reservoir, whereas hydrothermal calcites associated with gold veins (δ13C = −3.2 to −4.6) are interpreted to represent donation of carbon from a uniform reservoir containing carbonate, magmatic C, and carbonaceous components.The conjunction of trondhjemitic and lamprophyric rocks with major structures and gold deposits is interpreted in terms of transcrustal fractures utilized as a conduit for high-Na magmas from the base of the crust, for alkalic magmas from the mantle, and for discharge of hydrothermal fluids from a metamorphic or magmatic reservoir.
Evolution of the Boothia Uplift, arctic Canada
Authors: Okulitch A. V. , Packard J. J. , Zolnai A. I.
Published: April 2010

The Boothia Uplift extends 1000 km northward from the northern Canadian Shield into the Arctic Archipelago. Consisting of a core of Archean(?) to Aphebian gneissic units and a cover of Proterozoic to Devonian strata of the Arctic Platform and Franklinian Miogeocline, it formed during several minor pulses of uplift in the late Proterozoic and early Paleozoic and a major episode of tectonism during the Siluro-Devonian. Although it has long been regarded as a "horst" or vertical block uplift, compilation of new and previous data suggests that the uplift can be interpreted as a major, west-directed, imbricate mass of crystalline basement mantled by faulted and drape-folded cover. Details of the vertical component of movement have been provided by sedimentological and stratrigraphic studies. Uplift increases northward from the craton to a maximum of 5 km. Estimates of horizontal movement, predicated on assumed fault dips, could be as much as 30 km.Major tectonism of the Boothia Uplift was approximately coeval with uplift on southeastern Ellesmere Island and on northern Axel Heiberg Island, folding and low-grade metamorphism on northernmost Ellesmere Island, and west-directed thrusting and folding on Greenland. The plate tectonic interactions responsible for these events remain obscure; a general regime of west-directed compressive stresses associated with late stages of the Caledonian Orogeny may have been present.
Interpretation of magnetic susceptibility: a new approach to geophysical evaluation of the degree of rock alteration
Authors: Lapointe P. , Morris W. A. , Harding K. L.
Published: April 2010

Magnetic susceptibility measurements on cores from boreholes in the Eye–Dashwa lakes pluton, an Archean granitic pluton near Atikokan, Ontario, give a quantitative evaluation of the alteration level of these rocks. The histogram of the 5406 magnetic susceptibility measurements taken from 3.3 km of cores shows a multimodal distribution. In order to differentiate these subpopulations and to recognize their geological significance a numerical approach is employed. The magnetic susceptibility, when plotted on a log scale versus cumulative frequency on a probability scale, successfully differentiates the interval associated with each respective subpopulation. In the granite zone cut by the five boreholes, three distinct subpopulations are identified.The variation of magnetic susceptibility in the Eye–Dashwa lakes granitic cores studied is almost entirely associated with the oxidation state of the iron–titanium oxide minerals, since the variation in the total iron oxide content and the variation in grain size do not vary sufficiently to explain the large variation detected in the magnetic susceptibility logs. Hence, the variation in magnetic susceptibility is interpreted to be directly related to the alteration level seen in the rock (highly altered rock leads to lower magnetic susceptibility signal). Furthermore, the rocks characterized by the epidote group, the chlorite group, and the iron hydroxides, clays, and carbonate group each have a distinct magnetic susceptibility signature.By identifying the different levels of magnetic susceptibility values at this specific research area, the associated levels of alteration can be defined. Using this approach, a geologically interpreted geophysical log is produced. A three-dimensional representation of the five magnetic susceptibility bore-core logs is interpreted on the basis of similar magnetic susceptibility signature.The proposed approach has also been successfully applied to surface studies and is potentially useful in mineral exploration, especially in areas where mineralization is associated with fractured and altered rocks.
Age of xenocrystic zircon from diatremes of western Canada
Authors: Parrish R. R. , Reichenbach I.
Published: April 2010

Numerous diatremes of middle and late Paleozoic age intrude miogeoclinal middle and lower Paleozoic strata in the Canadian Cordillera. In addition to abundant crustal xenoliths and conspicuous mantle-derived mineral xenocrysts, rare zircon grains are present. U–Pb dating of single zircon crystals from many of these diatremes has failed to identify the presence of cogenetic (magmatic) zircons. All dated zircon grains are interpreted as xenocrysts derived from the crust. Their morphologies range from euhedral to very rounded, and their ages range from early Paleozoic to Archean. Most ages fall between 1.8 and 2.1 Ga, with subordinate age groupings in the late Archean (ca. 2.6 Ga), Middle Proterozoic (1.0–1.1 Ga), and early Paleozoic (ca. 470 Ma, 530 Ma). The Proterozoic and Archean zircons could have been derived from either the crystalline basement or its overlying sedimentary cover of Late Proterozoic to early Paleozoic age. Paleozoic zircons were probably derived from either intrusions within the basement or sills that intrude the early Paleozoic sedimentary cover, and they signify magmatic activity possibly related to rifting of the continental margin.
Attenuation of age- and sucrose-induced insulin resistance and syndrome X by a synergistic antioxidant cocktail: the AMIS syndrome and HISS hypothesisThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Lautt W. Wayne , Ming Zhi , Legare Dallas J.
Published: April 2010

Absence of meal-induced insulin sensitization (AMIS) results in a predictable progression of dysfunctions, including postprandial hyperglycemia, compensatory hyperinsulinemia, resultant hyperlipidemia, increased oxidative stress, and obesity, progressing to syndrome X and diabetes. To one year of age, rats show a slow development of AMIS, but this can be potentiated by addition of a low-dose sucrose supplement to the diet. Provision of a synergistic antioxidant cocktail consisting of S-adenosylmethionine, vitamin E, and vitamin C (Samec) attenuates the rate and extent of development of AMIS in both normal aging animals and in aging animals on the sucrose diet. Adiposity, assessed from weighed regional fat masses and from bioelectrical impedance to estimate whole-body adiposity, correlated strongly with AMIS (r2 = 0.7–0.8). Rats given the sucrose supplement had accelerated AMIS and developed fasting hyperinsulinemia and postprandial hyperglycemia, hyperlipidemia, hyperinsulinemia, and adiposity. Samec completely compensated for the negative impact of this sucrose supplement and attenuated development of the associated dysfunctions. AMIS is explained by the HISS (hepatic insulin-sensitizing substance) hypothesis, which is outlined in the paper.
Mechanisms associated with mitochondrial-generated reactive oxygen species in cancerThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Verschoor Meghan L. , Wilson Leigh A. , Singh Gurmit
Published: April 2010

The mitochondria are unique cellular organelles that contain their own genome and, in conjunction with the nucleus, are able to transcribe and translate genes encoding components of the electron transport chain (ETC). To do so, the mitochondria must communicate with the nucleus via the production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), which are produced as a byproduct of aerobic respiration within the mitochondria. Mitochondrial signaling is proposed to be altered in cancer cells, where the mitochondria are frequently found to harbor mutations within their genome and display altered functional characteristics leading to increased glycolysis. As signaling molecules, ROS oxidize and inhibit MAPK phosphatases resulting in enhanced proliferation and survival, an effect particularly advantageous to cancer cells. In terms of transcriptional regulation, ROS affect the phosphorylation, activation, oxidation, and DNA binding of transcription factors such as AP-1, NF-κB, p53, and HIF-1α, leading to changes in target gene expression. Increased ROS production by defective cancer cell mitochondria also results in the upregulation of the transcription factor Ets-1, a factor that has been increasingly associated with aggressive cancers.
Berberine inhibits NADPH oxidase mediated superoxide anion production in macrophagesThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Sarna Lindsei K. , Wu Nan , Hwang Sun-Young , Siow Yaw L. , O Karmin
Published: April 2010

Oxidative stress and amplified redox signaling contribute to the pathogenesis of many human diseases including atherosclerosis. The superoxide-generating phagocytic NADPH oxidase is a key source of oxidative stress in the developing atheroma. The aim of the present study was to examine the effect of berberine, a plant-derived alkaloid, on NADPH oxidase-mediated superoxide anion production in macrophages. Lipopolysaccharide (LPS) treatment activated NADPH oxidase in THP-1 monocyte-derived macrophages and increased the intracellular level of superoxide anions. Preincubation of cells with berberine demonstrated a concentration-dependent (10–50 µmol/L) and time-dependent (6–24 h) inhibition of superoxide anion generation in LPS-stimulated macrophages. Cell viability tests confirmed that berberine, at concentrations sufficient for inhibiting NADPH oxidase-mediated superoxide anion generation in macrophages, did not affect cell viability. Real-time PCR analysis revealed that addition of berberine to the culture medium was able to reduce gp91phoxmRNA expression in LPS-treated cells. Berberine also restored superoxide dismutase (SOD) activity, which was found to be inhibited by LPS treatment. In conclusion, results from the present study demonstrate that berberine can effectively reduce intracellular superoxide levels in LPS- stimulated macrophages. Such a restoration of cellular redox by berberine is mediated by its selective inhibition of gp91phoxexpression and enhancement of SOD activity. The therapeutic relevance of berberine in the prevention and management of atherosclerosis remains to be further investigated.
Heme oxygenase expression and Nrf2 signaling during hibernation in ground squirrelsThis article is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Ni Zhouli , Storey Kenneth B.
Published: April 2010

Mammalian hibernation is composed of long periods of deep torpor interspersed with brief periods of arousal in which the animals, fueled by high rates of oxygen-based thermogenesis in brown adipose tissue and skeletal muscle, power themselves back to euthermic (~37 °C) body temperatures. Strong antioxidant defences are important both for long-term cytoprotection during torpor and for coping with high rates of reactive oxygen species generated during arousal. The present study shows that the antioxidant enzyme heme oxygenase 1 (HO1) is strongly upregulated in selected organs of thirteen-lined ground squirrels (Spermophilus tridecemlineatus) during hibernation. Compared with euthermic controls, HO1 mRNA transcript levels were 1.4- to 3.8-fold higher in 5 organs of hibernating squirrels, whereas levels of the constitutive isozyme HO2 were unchanged. Similarly, HO1 protein levels increased by 1.5- to 2.0-fold in liver, kidney, heart, and brain during torpor. Strong increases in the levels of the Nrf2 transcription factor and its heterodimeric partner protein, MafG, in several tissues indicated the mechanism of activation of hibernation-responsive HO1 gene expression. Furthermore, subcellular distribution studies with liver showed increased nuclear translocation of both Nrf2 and MafG in torpid animals. The data are consistent with the suggestion that Nrf2-mediated upregulation of HO1 expression provides enhanced antioxidant defence to counter oxidative stress in hibernating squirrels during torpor and (or) arousal.
Oxidative stress and diabetic cardiovascular disorders: roles of mitochondria and NADPH oxidaseThis review is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Shen Garry X.
Published: April 2010

Cardiovascular diseases are the predominant cause of death in patients with diabetes mellitus. Underlying mechanism for the susceptibility of diabetic patients to cardiovascular diseases remains unclear. Elevated oxidative stress was detected in diabetic patients and in animal models of diabetes. Hyperglycemia, oxidatively modified atherogenic lipoproteins, and advanced glycation end products are linked to oxidative stress in diabetes. Mitochondria are one of major sources of reactive oxygen species (ROS) in cells. Mitochondrial dysfunction increases electron leak and the generation of ROS from the mitochondrial respiratory chain (MRC). High levels of glucose and lipids impair the activities of MRC complex enzymes. NADPH oxidase (NOX) generates superoxide from NADPH in cells. Increased NOX activity was detected in diabetic patients. Hyperglycemia and hyperlipidemia increased the expression of NOX in vascular endothelial cells. Accumulated lines of evidence indicate that oxidative stress induced by excessive ROS production is linked to many processes associated with diabetic cardiovascular complications. Overproduction of ROS resulting from mitochondrial dysfunction or NOX activation is associated with uncoupling of endothelial nitric oxide synthase, which leads to reduced production of nitric oxide and endothelial-dependent vasodilation. Gene silence or inhibitor of NOX reduced oxidized or glycated LDL-induced expression of plasminogen activator inhibitor-1 in endothelial cells. Statins, hypoglycemic agents, and exercise may reduce oxidative stress in diabetic patients through the reduction of NOX activity or the improvement of mitochondrial function, which may prevent or postpone the development of cardiovascular complications.
Zinc–metallothionein: a potential mediator of antioxidant defence mechanisms in response to dopamine-induced stressThis review is one of a selection of papers published in a Special Issue on Oxidative Stress in Health and Disease.
Authors: Eibl Joseph K. , Abdallah Zouleika , Ross Gregory M.
Published: April 2010

Clinically, Parkinson’s disease (PD) is a neurodegenerative disorder characterized by the development of tremors and rigidity that is found primarily in patients over the age of 50. At the cellular level, it is clear that the pathology of PD results from the progressive loss of dopaminergic neurons in the substantia nigra. Several lines of evidence have implicated oxidative stress as a contributing factor to the depletion of dopaminergic neurons in PD. Under conditions of oxidative stress, the neurotransmitter dopamine can be oxidized to form neurotoxic quinone and semiquinone products. While dopaquinones are known to be extremely reactive towards sulfhydryl groups of many cellular substrates, mounting evidence suggests that their toxic effects can be quenched by intrinsic antioxidant mechanisms (e.g., glutathione). However, to respond appropriately to differing levels of oxidative stress, cells require a mechanism to regulate an appropriate response. This manuscript proposes metallothionein as a major cellular sensor of oxidized dopamine stress and metallothionein-mediated Zn2+mobilization as an effecter signal that is used by the cell to manage oxidized dopamine as an intrinsic neurotoxin.
CAN MASSLESS AND LIGHT YUKAWAONS BE HARMLESS?
Authors: KOIDE YOSHIO
Published: April 2010

In the so-called yukawaon model, where the effective Yukawa coupling constants [Formula: see text] are given by vacuum expectation values (VEV's) of gauge singlet scalars (yukawaons) Yf with 3×3 components, i.e. [Formula: see text], massless (and light) scalars appear because a global flavor symmetry is assumed. In order to demonstrate whether such massless scalars in the yukawaon model are harmless or not, yukawaon masses are explicitly estimated, as an example, in the charged lepton sector.
DECAY OF DIRAC FIELDS IN THE BACKGROUNDS OF DILATONIC BLACK HOLES
Authors: BECAR RAMÓN , LEPE SAMUEL , SAAVEDRA JOEL
Published: April 2010

We find an exact solution to the Dirac equation in the background of the dilatonic black hole in 1 + 1 and 4 + 1 dimensions, and for them we calculate the corresponding quasinormal frequencies. In the two-dimensional case we find that for Weyl spinors the quasinormal modes' (QNM's) frequencies are pure imaginary and have negative sign for all modes, ensuring the stability of the (1 + 1)-dimensional dilatonic black hole. We generalize results to the (4 + 1)-dimensional dilatonic black hole, where the metric is product of a two-dimensional asymptotically flat geometry and a three-sphere with a constant radius. Our conclusion is that the QNMs are pure imaginary, as in the (1 + 1)-dimensional case.
Adenovirus infection results in alterations of insulin signaling and glucose homeostasis
Authors: Jiang Shaoning , Gavrikova Tatyana A. , Pereboev Alexander , Messina Joseph L.
Published: April 2010

Recombinant adenovirus (Ad) vectors can initiate an inflammatory response, limiting its use in gene therapy and basic research. Despite increased efforts to better understand Ad infection, little is known about how it affects cellular metabolic responses. In the current studies, we explored the effects of Ad vectors on insulin signaling molecules and glucose homeostasis. Nonreplicative Ad vectors were injected into rats through the tail vein, and at 4–13 days postinjection insulin signaling and glucose tolerance were examined. Ad vector infection significantly reduced total levels of the insulin receptor (IR), and insulin receptor substrates 1 and 2 (IRS-1, IRS-2) in the liver of rats, resulting in decreased insulin-induced tyrosine phosphorylation of IR, IRS-1, and IRS-2, and decreased interaction of IRS-1 and IRS-2 with phosphoinositide 3-kinase (PI3K). In addition, Ad infection resulted in impaired systemic glucose homeostasis, which recovered by 13 days, after the protein levels of IR, IRS-1, and IRS-2 had started to normalize. Expression of a TNF inhibitor or Kupffer cell depletion attenuated the Ad vector-induced decreases of insulin signaling molecules, indicating a potential role of Kupffer cell activation in this process. These studies provide evidence that systemic administration of Ad vectors can impair insulin signaling in liver, resulting in altered systemic glucose metabolism. Thus, effects of Ad vector infection on insulin action and glucose metabolism need to be considered when Ad vectors are used in research or gene therapy and may be more broadly applicable to other viral agents.
Architecture of inner medullary descending and ascending vasa recta: pathways for countercurrent exchange
Authors: Yuan Justin , Pannabecker Thomas L.
Published: April 2010

Pathways and densities of descending vasa recta (DVR) and ascending vasa recta (AVR) in the outer zone of the inner medulla (IM) were evaluated to better understand medullary countercurrent exchange. Nearly all urea transporter B (UT-B)-positive DVR, those vessels exhibiting a continuous endothelium, descend with little or no branching exclusively through the intercluster region. All DVR have a terminal fenestrated (PV-1-positive) segment that partially overlaps with the UT-B-positive segment. This fenestrated segment descends a distance equal to ∼15% of the length of the connecting UT-B-positive segment before formation of the first branch. The onset of branching is indicative of vessel entry into the intracluster region. The number density of UT-B-positive DVR at 3,000 μm below the OM-IM boundary is ∼60% lower than the density at 400 μm below the OM-IM boundary, a result of DVR joining to fenestrated interconnecting vessels and an overall decline in UT-B expression. AVR that lie in the intercluster region (designated AVR2) lie distant from CDs and ascend to the OM-IM boundary with little or no branching. AVR2arepresent a subcategory of AVR2that abut DVR. The mean DVR length (combined UT-B- and PV-1-positive segments) nearly equals the mean AVR2alength, implying a degree of overall equivalence in fluid and solute countercurrent exchange may exist. The AVR2/DVR ratio is ∼2:1, and the AVR2a/DVR ratio is ∼1:1; however, the AVR/DVR ratio determined for the full complement of fenestrated vessels is ∼4:1. The excess fenestrated vessels include vessels of the intracluster region (designated AVR1). Countercurrent exchange between vasa recta occurs predominantly in the intercluster region. This architecture supports previous functional estimates of capillary fluid uptake in the renal IM.