bluuebunny/crossref_metadata_2025 huggingface dataset:
Superplasticity of a Fine‐Grained TZ3Y Material Involving Dynamic Grain Growth and Dislocation Motion
Authors: Bernard‐Granger Guillaume , Addad Ahmed , Guizard Christian
Published: December 2009

Superplastic deformation of a fully dense TZ3Y material, having a starting grain size around 135–145 nm and depleted of any amorphous phase at grain boundaries, has been investigated using compressive creep tests in air in the temperature range of 1100°–1300°C and the real stress range of 50–100 MPa. The key parameters of the creep law have been determined by performing temperature changes at a fixed stress and stress jumps at a fixed temperature. From such experiments, an average value for the apparent stress exponent of around 3 is obtained when the applied stress varied from 50 to 100 MPa and the temperature was kept constant in the range of 1100°–1300°C. The apparent activation energy of the mechanism controlling the creep deformation is evaluated at 577±75 kJ/mol in the temperature range of 1200°–1300°C, for a real stress of 70 MPa. The values of the apparent grain size exponent can be calculated from the initial grain size in the as‐sintered samples and the grain size in the crept samples. In all cases, it was determined to be around 2. Observation of the microstructure of the crept samples, using scanning electron microscopy, reveals grain growth but does not show any significant elongation of the elemental grains. Transmission electron microscopy of a sample crept under 100 MPa at 1300°C reveals clear intragranular dislocation activity. This dislocation activity seems to be mainly confined in folds emitted at triple points. Because the creep parameters (experimental and calculated using a simple geometric model) and the microstructure observed are in good agreement, we propose that the creep mechanism involved is grain boundary sliding accommodated by dynamic grain growth and the formation of triple‐point folds.
Significance of Periodontal Risk Assessment in the recurrence of periodontitis and tooth loss
Authors: Matuliene G. , Studer R. , Lang N. P. , Schmidlin K. , Pjetursson B. E. , Salvi G. E. , Brägger U. , Zwahlen M.
Published: December 2009

Matuliene G, Studer R, Lang NP, Schmidlin K, Pjetursson BE, Salvi GE, Brägger U, Zwahlen M. Significance of Periodontal Risk Assessment on the recurrence of periodontitis and tooth loss. J Clin Periodontol 2010; 37: 191–199. doi: 10.1111/j.1600‐051X.2009.01508.x.

Aim: To investigate the association of the Periodontal Risk Assessment (PRA) model categories with periodontitis recurrence and tooth loss during supportive periodontal therapy (SPT) and to explore the role of patient compliance.

Material and Methods: In a retrospective cohort, PRA was performed for 160 patients after active periodontal therapy (APT) and after 9.5 ± 4.5 years of SPT. The recurrence of periodontitis and tooth loss were analysed according to the patient's risk profile (low, moderate or high) after APT and compliance with SPT. The association of risk factors with tooth loss and recurrence of periodontitis was investigated using logistic regression analysis.

Results: In 18.2% of patients with a low‐risk profile, in 42.2% of patients with a moderate‐risk profile and in 49.2% of patients with a high‐risk profile after APT, periodontitis recurred. During SPT, 1.61 ± 2.8 teeth/patient were lost. High‐risk profile patients lost significantly more teeth (2.59 ± 3.9) than patients with moderate‐ (1.02 ± 1.8) or low‐risk profiles (1.18 ± 1.9) (Kruskal–Wallis test, p=0.0229). Patients with erratic compliance lost significantly (Kruskal–Wallis test, p=0.0067) more teeth (3.11 ± 4.5) than patients compliant with SPT (1.07 ± 1.6).

Conclusions: In multivariate logistic regression analysis, a high‐risk patient profile according to the PRA model at the end of APT was associated with recurrence of periodontitis. Another significant factor for recurrence of periodontitis was an SPT duration of more than 10 years.
ORIGINAL ARTICLE: Can Sulfasalazine Prevent Infection‐Mediated Pre‐Term Birth in a Murine Model?
Authors: Nath Carl A. , Ananth Cande V. , Smulian John C. , Peltier Morgan R.
Published: December 2009

Citation Nath CA, Ananth CV, Smulian JC, Peltier MR. Can sulfasalazine prevent infection‐mediated pre‐term birth in a murine model? Am J Reprod Immunol 2010; 63: 144–149

Problem  Sulfasalazine (SASP) blocks activation of nuclear factor‐kappa B (NF‐κB) in gestational tissues in vitro– one of the earliest signals in the inflammatory response. We hypothesized that the administration of SASP would reduce the rate of infection‐mediated pre‐term birth in a murine model.

Method of study  CD‐1 mice (n = 40) were assigned on gestational day (gd) 14.5 to 1 of 3 treatments: (1) Sham infection and vehicle; (2) 104 CFU Escherichia coli and vehicle; or (3) 104 CFU E. coli and SASP (150 mg/Kg daily). Mice were observed twice daily and deliveries prior to gd 18.5 were considered pre‐term.

Results  Significantly more mice delivered prior to gd 18.5 when infected with 104 CFU E. coli than sham‐infected mice (P < 0.001) and this effect was significantly reduced in mice also treated with SASP (P = 0.002). SASP also tended to increase litter size (P = 0.060) and significantly increased weight of pups born to dams with intrauterine infections (P = 0.001).

Conclusion  SASP reduced rates of pre‐term delivery and improved pregnancy outcomes for mice infected with 104 CFU E. coli. This suggests that SASP has the potential to play a role in strategies to prevent pre‐term birth in women.
Effect of Calcium Propionate and Water Activity on Growth and Aflatoxins Production by Aspergillus flavus
Authors: Alam Sahib , Shah Hamid Ullah , Magan Naresh
Published: December 2009

ABSTRACT:  The efficacy of calcium propionate at 2 different doses (0.5% and 1%) against growth and aflatoxins production by Aspergillus flavus (A‐2092) was investigated in vitro on Czapek yeast extract agar at different levels of water activity (aw) in the range of 0.94 to 0.996aw. A. flavus spores germinated on all calcium propionate and aw treatments; however, 1% calcium propionate at 0.94 aw delayed the germination process for up to 10 d. The growing rate of mycelia was slower (0.28 mm/d) at 1% calcium propionate and 0.94 aw. Aflatoxins (B1, B2, G1, and G2) were also produced minimally (36.1, 1, 1.86, and 1.01 ng/g of media, respectively) at the aforementioned dose rate of calcium propionate and water activity. It was concluded that addition of calcium propionate and aw amelioration can prove effective tools for suppressing the germination, growth rate, and aflatoxins production by A. flavus in substrate.
Metabolic engineering, new antibiotics and biofilm viscoelasticity
Authors: Daniels Craig , Espinosa‐Urgel Manuel , Niqui‐Arroyo José‐Luis , Michán Carmen , Ramos Juan L.
Published: December 2009

In the following highlight we refer to a number of new advances in the field of Biotechnology that address issues relating to the synthesis of new antibiotics, new biocatalysts and matrices in biofilms.
Between the National and the Global: Exploring Tensions in Canadian Citizenship Education
Authors: Richardson George H. , Abbott Laurence
Published: December 2009

Over the last fifteen years, most national public education systems have added some component of ‘global citizenship education’ to their existing civic education curricula. This move to expand the confines of citizenship education has generally been applauded as a way in which schools might better prepare students to understand and address the challenges and possibilities of globalisation. However, a close analysis of curriculum documents in Canada tends to highlight the fact that in terms of civic education, significant ideological tensions exist between global citizenship and national citizenship. In this article, we draw on Canadian civics and social studies curricula from across Canada to examine the different sources of civic tensions between the ‘national’ and the ‘global’.
Britishness in Trafalgar Square: Urban Place and the Construction of National Identity
Authors: Sumartojo Shanti
Published: December 2009

This article argues for the importance of urban public place in exploring how contemporary national identity is constructed. I take Trafalgar Square as my case study, exploring how Britishness was reinvented in two events that took place there in 2005: the celebrations for London's successful Olympic host city bid and the commemorative vigil for the victims of the 7 July London bombings. I contend that during these events, Trafalgar Square contributed to the discourse of national identity in three distinct ways: firstly, as a podium for the promulgation of official messages about the two events; secondly, as a tableau that demonstrated the ‘diversity in unity’ that official messages emphasised; and finally as a physical frame that accessed a version of British history to contextualise the events. More generally, the use of the square helped illuminate some important tensions at the heart of contemporary national identity in Britain, such as the question of multiculturalism and the role of London in the national imagination.
Irregular Au profile on the SiO2 surface and at the SiO2∕Si interface and the oxidation kinetics of thermally oxidized Au-contaminated n-Si (001) surfaces
Authors: Shimizu H. , Shimada S. , Nagase S. , Muta S. , Ikeda M.
Published: December 2009

The authors have studied the Au profile near the SiO2∕Si interface as a function of oxidation temperature and clarified the oxidation mechanism. Clusterlike Au granules were observed on the surface of the SiO2 film (the Au surface concentration was 1.7×1015at.∕cm2) of thermally oxidized Au-contaminated Si wafers, oxidized between 823 and 1123K. As the oxidation temperature was increased, the Au granular clusters grew competitively. The clusters were observed to be both on the surface of the SiO2 film and at the SiO2∕Si interface. The Au clusters were found not to bond with other elements such as O, H, and Si. The existence of a depleted or weakly inverted layer at the Si surface indicated the formation of a Au∕n-Si Schottky barrier. Regarding the oxidation kinetics between 823 and 1173K, Au rapidly enhances the growth rate of SiO2 (for SiO2 thicknesses of less than ∼10nm). This result shows that Au acts as a catalyst to promote the initial growth of SiO2 on Si (001) surfaces.
Podcasts as Tools in Introductory Environmental Studies
Authors: Vatovec Christine , Balser Teri
Published: December 2009

Technological tools have increasingly become a part of the college classroom, often appealing to teachers because of their potential to increase student engagement with course materials. Podcasts in particular have gained popularity as tools to better inform students by providing access to lectures outside of the classroom. In this paper, we argue that educators should expand course materials to include prepublished podcasts to engage students with both course topics and a broader skill set for evaluating readily available media. We present a pre- and postassignment survey evaluation assessing student preferences for using podcasts and the ability of a podcast assignment to support learning objectives in an introductory environmental studies course. Overall, students reported that the podcasts were useful tools for learning, easy to use, and increased their understanding of course topics. However, students also provided insightful comments on visual versus aural learning styles, leading us to recommend assigning video podcasts or providing text-based transcripts along with audio podcasts. A qualitative analysis of survey data provides evidence that the podcast assignment supported the course learning objective for students to demonstrate critical evaluation of media messages. Finally, we provide recommendations for selecting published podcasts and designing podcast assignments.
Development of Higher-Level Cognitive Skills In a Learner-Centered Lab on Extensions of Mendelian Inheritance Using
Drosophila
Authors: Marshall Pamela A.
Published: December 2009

Students can have difficulty comprehending complex concepts in science. They can memorize the definition but do not understand the underlying biological principles. In the Fundamentals of Genetics course at Arizona State University at the West campus, students grapple with the topic of “extensions of Mendelism.” Additionally, in lab, students are challenged by scoring phenotypes that are not binary. Both of these concepts require that students understand not only inheritance but also the principles of protein structure and function. A genetics laboratory exercise was developed that combines study of some extensions of Mendelian inheritance with practice in manipulating
Drosophila melanogaster
and scoring subtle and variable phenotypes. Students analyze
Drosophila
with mutations that demonstrate some extensions of Mendelian inheritance: temperature sensitivity, variable expressivity, incomplete penetrance, multiple alleles, dosage compensation, and gene dosage effect. The phenotypes in some of these mutants differ from individual to individual and are difficult to discern; thus, students also gain experience in investigating challenging phenotypes. Pre- and postlab assessments indicate that performing this exercise increased students’ mastery of the molecular basis of extensions of Mendelian inheritance and their abilities in scoring and manipulating flies. This is a discovery-based lab exercise in which students examine some extensions of Mendelian inheritance and gain experience in analyzing complex traits in
Drosophila
.
Construction and Evaluation of an Online Microbiology Course for Nonscience Majors
Authors: Hughes Lee
Published: December 2009

The development of web-based technologies provides a new method for course delivery. As with any new technique, evaluation is a necessary tool to determine if the method is consistent with expectations. This study describes the conversion of a nonscience majors’ microbiology lecture course to online delivery and evaluates the hypothesis that the online course can be as effective as the traditional course. Course examination scores are compared between the face-to-face and online sections over a 3-year period. On all but one of the course examinations, no significant difference is found for those students in these two distinctly different course types. The success rate, as defined by those students earning grades of C or better, is high for both course types, although the traditional course success rate is slightly higher. Student evaluations of the courses are also positive, though some differences are noted. Overall, student performance in the online course is equivalent to that in the traditional course.
Immunophenotypic distinction between pigmented villonodular synovitis and haemosiderotic synovitis
Authors: Mahendra G , Kliskey K , Athanasou N A
Published: December 2009

Aim:

Haemosiderotic synovitis (HS) is caused by excessive bleeding into a joint. It occurs secondary to a variety of conditions and needs to be distinguished from pigmented villonodular synovitis (PVNS) for the purposes of treatment. The histopathological distinction between these conditions, particularly in biopsy specimens, can be problematic.

Methods:

Immunophenotypic findings in 20 cases of PVNS and 20 cases of HS were analysed using monoclonal antibodies against proliferation (Ki-67), apoptosis (bcl2), macrophage (CD14, CD68, HLA-DR) and osteoclast (CD51) antigens.

Results:

Macrophages in PVNS and HS expressed CD14 and HLA-DR. The giant cells in PVNS, but not those in HS, expressed CD51 and were negative for CD14 and HLA-DR, indicating that these cells had an osteoclast phenotype. Considerably more CD51-expressing mononuclear cells were noted in PVNS compared with HS. The Ki-67 proliferation index was higher in PVNS than in HS.

Conclusions:

The findings indicate that there are immunophenotypic differences in giant cells between PVNS and HS, and that expression of CD51 and a high Ki-67 index effectively distinguishes between these two conditions.
Female-type fibrocystic disease with papillary hyperplasia in a male breast
Authors: Robertson K E , Kazmi S A , Jordan L B
Published: December 2009

Fibrocystic disease is a common benign finding in the female breast and often presents as a palpable mass. It is much less commonly found in the male breast. A case is reported of a young man with female-type fibrocystic disease associated with papillary hyperplasia in the right breast.
Rights, respect for dignity and end-of-life care: time for a change in the concept of informed consent
Authors: Freeman J M
Published: December 2009

The current concepts of autonomy, surrogate autonomy and informed consent often lead to futile and expensive care at the ends of life. They may impinge on the dignity of the patient as well as subject society to unwarranted expense. In order to provide affordable healthcare for all, these concepts are in need of modification.
Ascribing intentions in clinical decision-making
Authors: Jansen L A , Fogel J S
Published: December 2009

Background:

The intentions of clinicians are widely considered to be relevant to the ethical assessment of their actions. A better understanding of the psychological factors that influence the ascription of intentions in clinical practice is important for improving the self-understanding of clinical decision-making and, ultimately, the ethics of clinical care. Drawing on empirical research on intentionality that has been done in other contexts, this is the first study to test whether the “asymmetric effect” of intention ascription is exhibited by respondents when presented with clinical decision-making scenarios.

Objective:

To assess how individuals attribute intentions to clinical actors in clinical decision-making scenarios.

Methods:

A total of 149 first and second year medical students was randomly assigned to two groups (group A, group B). Subjects in each group read two scenarios and submitted anonymous responses to questions regarding each scenario.

Results:

The asymmetric effect was strongly exhibited by the responses given to scenario 2, but it was not exhibited by the responses given to scenario 1.

Conclusion:

The present study provided evidence for the view that people’s ascription of intentions to others is influenced by their previous evaluative judgement of the conduct in question.
Medical ethics and law for doctors of tomorrow: the 1998 Consensus Statement updated
Authors: Stirrat G M , Johnston C , Gillon R , Boyd K
Published: December 2009

Knowledge of the ethical and legal basis of medicine is as essential to clinical practice as an understanding of basic medical sciences. In the UK, the General Medical Council (GMC) requires that medical graduates behave according to ethical and legal principles and must know about and comply with the GMC’s ethical guidance and standards. We suggest that these standards can only be achieved when the teaching and learning of medical ethics, law and professionalism are fundamental to, and thoroughly integrated both vertically and horizontally throughout, the curricula of all medical schools as a shared obligation of all teachers. The GMC also requires that each medical school provides adequate teaching time and resources to achieve the above. We reiterate that the adequate provision and coordination of teaching and learning of ethics and law requires at least one full-time senior academic in ethics and law with relevant professional and academic expertise. In this paper we set out an updated indicative core content of learning for medical ethics and law in UK medical schools and describe its origins and the consultative process by which it was achieved.
Petrology of the Early Proterozoic Burakovsky layered intrusion, southern Karelia, Russia: mineral and whole-rock major-element chemistry
Authors: Higgins S. J. , Snyder G. A. , Mitchell J. N. , Taylor L. A. , Sharkov E. V. , Bogatikov O. A. , Grokhovskaya T. L. , Chistyakov A. V. , Ganin V. A. , Grinevich N. G.
Published: December 2009

The Early Proterozoic (2449 ± 1.1 Ma) Burakovsky layered intrusion of southern Karelia, Russia, is the largest (700 km2) mafic pluton in the Fennoscandian Shield. The layered series contains two main parts: (i) an ultramafic series (85% dunite), and (ii) a mafic series (mostly gabbros). Mineral and whole-rock chemical variations in the ultramafic zone indicate little variation in chemistry over the entire sequence (e.g., in olivine, variations are from Fo89 to Fo87 over the upper 1600 m). In contrast, the Mg# in pyroxenes from the gabbronorite zone varies from 85 to 58 over an interval of 500 m. On the basis of the current data, there are no apparent reversals in chemistry in the ultramafic zone, whereas there is evidence for several in the gabbronorite zone. Furthermore, there is a distinctive reversal to more primitive compositions in mineral and whole-rock chemistry at the top of the ultramafic zone. These differences indicate that either (i) the gabbronorite zone crystallized from the residue left from formation of the ultramafic zone and the subsequent "flushing" of the more evolved portions to form the Early Proterozoic Karelian volcanic fields, or (ii) there were two separate magmas. Plagioclase crystals from the gabbronorite zone are chemically zoned, providing evidence of the local processes affecting crystallization of this sequence. Plagioclase crystals from near the base commonly display relatively Na-rich cores that are believed to result from either supersaturation at the onset of nucleation or the prior crystallization of some other, Ca-rich phase (e.g., clinopyroxene). Many plagioclase grains also contain reversely zoned rims, indicative of either (i) exchange between trapped liquid and the main magma during times of replenishment; or (ii) an increase in the CIPW-normative plagioclase–liquid partition coefficient for Ca, due to an increase in the augite component of the melt. The lack of evidence for abundant magma influxes in the ultramafic zone contrasts with the chemical reversals observed in the gabbronorite zone, suggesting that replenishment was a prevailing process only in the upper half of the intrusion.
The Paleoproterozoic (2.5–1.7 Ga) Midcontinent rift system of the northeastern Fennoscandian Shield
Authors: Smolkin V. F.
Published: December 2009

The Karelian epoch of tectono-magmatic activity resulted in an intensive structural–tectonic rearrangement of Archean crustal blocks, origination, development, and orogenesis of the Pechenga – Varzuga belt. Being emplaced on the Archean crust of the continental type, the Pechenga – Varzuga belt is an intracontinental paleorift system formed during four stages: prerifting (2.55–2.30 Ga), early rifting (2.30–2.20 Ga), late rifting (2.20–1.95 Ga), and orogenic (1.95–1.70 Ga). During the stage of 2.55–2.30 Ga, as a result of formation of an extensive asthenolens whose projection to the surface covered most of the Kola – Lapland – Karelian province, there appeared paleoaulacogen depressions and mantle and crustal magma associations with normal alkalinity: gabbronorite dykes (2.55–2.40 Ga), low-Ti picrite–basalt (2.45–2.41 Ga), basalt, andesite–basalt (initial 87Sr/86Sr = 0.7042) and dacite volcanics, peridotite–pyroxenite–gabbronorite (2.50–2.43 Ga, εNd = −1, −2), lherzolite–gabbronorite (or drusite) (2.45 Ga), and gabbro–anorthosite (2.45 Ga) layered intrusions characterized by chromite, platinum, and titanomagnetite mineralization. As the rocks of Archean blocks were generally warmed up, intracrustal chambers of granitoid magmas were common. During the stage of 2.30–2.20 Ga, the asthenolens broke up and differentiation of its fragments significantly increased. Over the most heated fragments, the paleorift system (Pechenga–Varzuga belt) appeared, accompanied by generation of mantle melts with higher alkalinity (volcanic series of picrite – trachybasalt – trachyandesitic basalts, 87Sr/86Sr = 0.7035). During the third stage (2.20–1.95 Ga), rifting reached its maximum owing to intense sinistral fault-rifting, and mantle sources of deep ferropicritic (87Sr/86Sr = 0.7032; εNd = +1.6) and shallow tholeiitic basalt (87Sr/86Sr = 0.7021) melts formed at different depths; eruption of these magmas gave rise to thick volcanic sequences (1.98 Ga), Ni – Cu-bearing differentiated gabbro–wehrlite intrusions (1.98–1.90 Ga, 87Sr/86Sr = 0.7029; εNd = +1.5), and cogenetic, peridotite – olivine gabbro dyke swarms (1.96 Ga, εNd = +1.4), which are characterized by the elevated Fe, Ti, P, and light rare earth element contents. Intrusions of sulfide-bearing gabbronorite and websterite formed in the Lapland–Kolvitsa granulite belt, which experienced collision and high-grade (6–10 kbar (1 kbar = 100 MPa)) metamorphism. During the final stage (1.95–1.70 Ga), enclosure and orogenesis of the paleorift system took place; these events were accompanied by extensive development of mixed mantle–crustal and crustal sources, the formation of calc-alkaline volcanic and sedimentary orogenic associations, and the emplacement of P–Ti-bearing alkaline gabbro – nepheline syenite and U – Mo-bearing monzonite–granodiorite intrusions.
Platinum-group-element distribution in subcontinental mantle: evidence from the Ivrea Zone (Italy) and the Betic – Rifean cordillera (Spain and Morocco)
Authors: Garuti Giorgio , Oddone Massimo , Torres-Ruiz José
Published: December 2009

The six platinum-group elements (PGE's) Os, Ir, Ru, Rh, Pt, and Pd and Au were analyzed by instrumental neutron-activation analysis after nickel sulfide fire assay, in peridotites and dyke rocks from the orogenic ultramafic massifs of the Ivrea Zone in the Italian western Alps (Baldissero, Balmuccia, Finero) and the Betico–Rifean cordillera in southern Spain and northern Morocco (Ronda, Beni Bousera). The peridotites are considered as variably depleted, and reenriched low lithosphere, whereas the dyke rocks represent polybaric derivatives of basaltic melts (pyroxenites and gabbros), most coming from the underlying asthenosphere. The peridotites have total PGE content in the range 8.6–54.7 ppb, while mantle-normalized patterns generally grade from nearly flat and PGE rich, in less depleted lherzolites, to negative and PGE poor, in residual harzburgites and dunites. Dyke rocks have total PGE's in the range 5.4 – 250 ppb and positive mantle-normalized patterns. Negative anomalies of Ir – Pt are frequently observed in dykes, indicating that both metals were probably retained in the mantle source of these melts. Most of the peridotites display positive anomaly of Au, and in some case are enriched in Ru, Rh, and Pd, but exhibit the same negative anomalies in Ir and Pt as the dykes. These features are ascribed to reintroduction of noble metals into the residual mantle by reaction with the basaltic melts that generated the dykes, or alternatively by recycling of "dyke material" during further partial melting of the host mantle. The role of the sulfide phase as carrier of the recycled PGE is stressed by clear interelemental correlation in peridotites from the Ivrea Zone. Present data provide evidence that zones of PGE enrichment can origin; this way in the subcontinental mantle, and may constitute a potential reservoir for noble metal fertile volcanism in continental rift systems.
Origin of evolved magmas in the Midcontinent rift system, northeast Minnesota: Nd-isotope evidence for melting of Archean crust
Authors: Vervoort Jeffrey D. , Green John C.
Published: December 2009

The North Shore Volcanic Group (NSVG) of northeast Minnesota is a thick (9 km) sequence of plateau volcanic rocks that constitutes an important part of the Midcontinent rift system. This volcanic sequence is unique among the Midcontinent rift lavas, because it is composed of up to 25% rhyolite flows. We have analyzed Sm- and Nd-isotope compositions of 20 of the largest rhyolite and icelandite flows from the NSVG and seven comparably sized granophyres in the subjacent Duluth and Beaver Bay complexes. The lavas vary in composition from primitive basalt and basaltic andesite to icelandite and rhyolite, with a bimodal distribution. The rhyolites have much lower initial εNd values (−2 to −15, most samples < −10) than either the icelandites (0 to −6) or granophyres (0 to −8). Most rhyolites cannot be related to either the icelandites or more mafic magmas by simple fractionation, but rather have been produced by melting and assimilation of older, evolved crust. We suggest that the bimodal magmatism in the NSVG, and probably throughout the Midcontinent rift, has been produced by two fundamentally different processes. The bulk of the magmatism is basaltic; magmas originate in the mantle and migrate through the lithosphère with minor compositional change. Assimilation and fractional crystallization occur to varying degrees in the crust and, in some cases, produce icelandites, some small-volume rhyolites, and the granophyres, with Nd compositions dominated by the mantle component. The melting that produced the large-volume rhyolites is the result of a multistage process induced by these mantle-derived magmas that pond within the crust. This process appears to occur during a period of slowed extension and causes widespread heating and eventually localized extensive melting of the crust.
The Chengwatana Volcanics, Wisconsin and Minnesota: petrogenesis of the southernmost volcanic rocks exposed in the Midcontinent rift
Authors: Wirth Karl R. , Naiman Zachary J. , Vervoort Jeffrey D.
Published: December 2009

The southernmost exposed rocks of the North American Midcontinent rift system (1100 Ma) consist of 3000 m of mafic volcanic flows and minor interflow sediment exposed along the St. Croix River in Minnesota and Wisconsin. The flows are mostly high-Fe tholeiitic basalt with plagioclase phenocrysts and ophitic to subophitic clinopyroxene. Abundant secondary chlorite, epidote, and actinolite indicate the group was metamorphosed to greenschist facies (~350 °C). Low sodium (M4 site) and tetrahedral aluminum (AlIV) contents of actinolite indicate low-pressure metamorphism (0.25 GPa) and imply a geothermal gradient of 45 – 50 °C/km. Low magnesium (Mg# = 0.37–0.58) and Ni contents (36–185 ppm) indicate the basalts have undergone significant fractionation and are not primary mantle melts. Incompatible element abundances are inversely correlated with Mg#, and most samples plot within either high or low trace element groups (e.g., Ti, P, Zr). The basalts are enriched in the light rare earth elements and Th, and are variably depleted in Ta and Nb relative to La and Th. Initial 143Nd/144Nd compositions of the group range from 0.51099 to 0.51122 (initial εNd = −4.5 to +0.1). Most flows have isotopic compositions within a relatively limited range (initial εNd = −2.5 to −1.6), but exhibit variable trace element abundances. Flows with the highest and lowest initial 143Nd/144Nd ratios have isotopic compositions that are inversely correlated with trace element abundances and ratios (e.g., La/Yb, Th/La, Th/Ta). The combined geochemical data suggest that the Chengwatana basalts originated from plume-derived melts and underwent variable fractional crystallization and crustal contamination. These melts may have interacted with lithospheric mantle enriched during Penokean subduction.
Quercetin’s effect on cycling efficiency and substrate utilization
Authors: Dumke Charles L. , Nieman David C. , Utter Alan C. , Rigby Michael D. , Quindry John C. , Triplett N. Travis , McAnulty Steven R. , McAnulty Lisa S.
Published: December 2009

Previous evidence suggests that quercetin supplementation increases performance in humans. We examined the effects of 3 weeks of quercetin supplementation on fuel utilization, gross efficiency (GE), and perceived effort during 3 h of cycling over 3 successive days. Forty cyclists were randomized into quercetin and placebo groups and tested for maximal oxygen consumption (53.2 ± 1.2 and 54.7 ± 1.1 mL·kg–1·min–1). For 3 weeks following maximal oxygen consumption testing, subjects supplemented either 1000 mg·day–1quercetin or placebo during normal training. Following supplementation, subjects cycled at 57% maximum power for 3 h, on 3 successive days, using their own bicycles fitted to CompuTrainer Pro Model trainers (RacerMate, Seattle, Wash.). Metabolic measurements were taken every 30 min for each 3-h ride. Muscle biopsies obtained from the vastus lateralis immediately pre-exercise and postexercise on days 1 and 3 were analyzed for muscle glycogen content. Power output remained constant for all 3 exercise trials, but significant decreases over time were measured for GE, cadence, respiratory exchange ratio, blood glucose, and muscle glycogen. Significant increases were measured for heart rate and volume of oxygen consumption over time. No quercetin treatment effect was observed for any of the outcome measures in this study. These data indicate that GE is reduced during an exhausting 3-h bout of exercise. However, quercetin did not significantly affect any outcomes in these already well-trained subjects.
Serum uric acid is associated with metabolic risk factors for cardiovascular disease in the Uygur population
Authors: Li Nan F. , Wang Hong M. , Yang Jin , Zhou Ling , Yao Xiao G. , Hong Jing
Published: December 2009

The prevalence of hyperuricemia is low in Uygurs, who have a high prevalence of cardiovascular risk factors such as hypertension, overweight–obesity, dyslipidemia, hyperglycemia, and insulin resistance (IR). This study sought to investigate the relationships between serum uric acid (UA) and these risk factors in this population. A cross-sectional study was conducted in Uygurs (859 males, 1268 females) aged 20 to 70 years. Demographic data, systolic blood pressure (SBP), diastolic blood pressure (DBP), body mass index (BMI), and fasting and postprandial blood were obtained, and biological measurements were determined. The mean of BMI, SBP, DBP, total cholesterol, high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), triglycerides, fasting blood glucose, fasting insulin, and homeostasis model assessment insulin resistance index (HOMA-IR), and the prevalence of hypertension, IR, hyperglycemia, overweight–obesity, hypercholesteremia, hyper-LDL-c, and hypertriglyceridemia increased with UA but the prevalence of hypo-HDL-c decreased (p < 0.05). Logistic regression analysis showed that the odds ratios for IR, overweight–obesity, hypercholesteremia, hyper-LDL-c, and hypertriglyceridemia against the lowest UA group increased but decreased for hypo-HDL-c (p < 0.05). The UA in the hypo-HDL-c group was lower than that of the controls; the prevalence of hypo-HDL-c in hyperuricemia subjects was lower than in those with normal UA (p < 0.05). But the opposite results were observed between overweight–obesity, hyperglycemia, IR, hypercholesteremia, hypertriglyceridemia, and hyper-LDL-c and correspondence controls, respectively (p < 0.05). In Uygur, elevated UA is associated with overweight–obesity, hypercholesteremia, hyper-LDL-c, hypertriglyceridemia, hyperglycemia, and IR. The HDL-c level significantly increases with UA, whereas the prevalence of hypo-HDL-c decreases. Further studies are needed to clarify why UA is positively correlated to HDL-c.
The effect of prior heavy exercise on the parameters of the power-duration curve for cycle ergometry
Authors: Miura Akira , Shiragiku Chiaki , Hirotoshi Yuiko , Kitano Asami , Endo Masako Yamaoka , Barstow Thomas J. , Morton R. Hugh , Fukuba Yoshiyuki
Published: December 2009

The tolerable duration (t) of high-intensity cycle ergometry is well characterized by a hyperbolic function of power output (P) with an asymptote (termed the critical power (CP)) and a curvature constant (denoted W′). The purpose of this study was to investigate the effect of prior heavy exercise (W-up) that specifically engenders an acidosis on CP and W′. Eight healthy subjects performed 2 sets of 4 high-intensity square-wave exercise bouts on a bicycle ergometer to estimate CP and W′, with (W-up) and without (control) prior exercise, respectively. Exercise intensities of the 4 main bouts were selected in the range of 90% to 135% peak oxygen uptake so as to reach the limit of tolerance between approximately 1.5 and 10 min. The W-up bout was preceded by 6 min cycling at a work rate halfway between the lactate threshold and peak oxygen uptake (mean ± SD of 153.8 ± 29.8 W) starting 12 min before the main bout. Blood lactate levels ([La]b) just before the main exercise bouts in W-up conditions were significantly higher than those of the control (4.7 ± 1.1 and 1.4 ± 0.4 mEq·L–1, respectively; p < 0.05). However, there were no significant differences in end-exercise [La]b. W-up increased significantly the tolerable duration at every work rate compared with the control, which was attributable exclusively to increased CP (176.5 ± 34.3 and 168.7 ± 31.3 W, respectively; p < 0.05), without any significant change in W′ (11.0 ± 3.2 and 11.0 ± 3.1 kJ, respectively). It is concluded that the prior heavy exercise improved performance mainly because of an enhanced aerobic component of exercise energetics, as indicated by a higher CP and lower increment in the [La]b.
Acute effects of chocolate milk and a commercial recovery beverage on postexercise recovery indices and endurance cycling performance
Authors: Pritchett Kelly , Bishop Philip , Pritchett Robert , Green Matt , Katica Charlie
Published: December 2009

To maximize training quality, athletes have sought nutritional supplements that optimize recovery. This study compared chocolate milk (CHOC) with a carbohydrate replacement beverage (CRB) as a recovery aid after intense exercise, regarding performance and muscle damage markers in trained cyclists. Ten regional-level cyclists and triathletes (maximal oxygen uptake 55.2 ± 7.2 mL·kg–1·min–1) completed a high-intensity intermittent exercise protocol, then 15–18 h later performed a performance trial at 85% of maximal oxygen uptake to exhaustion. Participants consumed 1.0 g carbohydrate·kg–1·h–1 of a randomly assigned isocaloric beverage (CHOC or CRB) after the first high-intensity intermittent exercise session. The same protocol was repeated 1 week later with the other beverage. A 1-way repeated measures analysis of variance revealed no significant difference (p = 0.91) between trials for time to exhaustion at 85% of maximal oxygen uptake (CHOC 13 ± 10.2 min, CRB 13.5 ± 8.9 min). The change in creatine kinase (CK) was significantly (p < 0.05) greater in the CRB trial than in the CHOC trial (increase CHOC 27.9 ± 134.8 U·L–1, CRB 211.9 ± 192.5 U·L–1), with differences not significant for CK levels before the second exercise session (CHOC 394.8 ± 166.1 U·L–1, CRB 489.1 ± 264.4 U·L–1) between the 2 trials. These findings indicate no difference between CHOC and this commercial beverage as potential recovery aids for cyclists between intense workouts.
Effects of magnesium on exercise performance and plasma glucose and lactate concentrations in rats using a novel blood-sampling technique
Authors: Chen Ying-Ju , Chen Hsuan-Ying , Wang Ming-Fu , Hsu Mei-Hsiang , Liang Woei-Ming , Cheng Fu-Chou
Published: December 2009

Repeated blood sampling in rodents is often necessary and difficult. Magnesium has been touted as an agent for enhancing physical activity. An auto-blood-sampling device coupled with a microdialysis analyzer was developed to determine blood glucose and lactate concentrations in rats subjected to treadmill exercise. The effects of magnesium on exercise performance and blood energy metabolism were also evaluated. Sprague–Dawley rats fed a magnesium-adequate diet were randomly assigned to 2 experimental groups. Exercise performance was evaluated at 3 treadmill speeds (10, 15, and 20 m·min–1) with or without magnesium administration (90 mg·kg–1, intraperitoneal) in the first experiment. In the other experiment, each rat was fitted with a catheter in the jugular vein for collection of blood samples during the treadmill exercise at a speed of 20 m·min–1. Exercise performance was significantly higher at the lower speed of 10 m·min–1 in the control group. In addition, exercise performance was significantly enhanced only at 20 m·min–1 in the magnesium-sulfate-treated group when compared with the control group. Blood samples were collected every 15 min. Glucose concentrations increased significantly and then declined immediately after completion of the exercise task at 20 m·min–1 in both groups. However, glucose concentrations increased immediately after administration of magnesium and increased further during exercise when compared with those of the control group. Findings from a repeated blood-sampling assay suggest that increased blood glucose contributes to enhanced exercise performance by rats injected intraperitoneally with magnesium.
Effect of extracellular osmolality on metabolism in contracting mammalian skeletal muscle in vitro
Authors: Cermak Naomi M. , LeBlanc Paul J. , Peters Sandra J. , Vandenboom Rene , Roy Brian D.
Published: December 2009

Extensive research has been conducted on hepatocyte metabolism perturbed under the influence of anisosmotic stress. However, much less is known about the behaviour of skeletal muscle metabolism under similar conditions. After establishing a working model to study anisosmotic stress in resting mammalian skeletal muscle, the current study tested the hypothesis that hyperosmotic (HYPER) stress would lead to increased creatine, lactate, and measured enzyme activity, whereas hypo-osmotic (HYPO) stress would lead to decreased metabolites and enzyme activity vs. iso-osmotic (ISO) stress post contraction. Rat soleus (SOL) and extensor digitorum longus (EDL) were isolated and incubated in an organ bath (95% O2, 5% CO2, pH 7.4, 25 °C) altered to targeted osmotic conditions (ISO, 290 osmol·L–1; HYPO, 180 osmol·L–1; HYPER, 400 osmol·L–1). Muscle samples were flash frozen after 10 min of contraction. Post contraction, muscle water content in the SOL HYPO condition was 18% greater than ISO, and HYPER had approximately 14% less water content than ISO (p < 0.05). In the HYPO condition, EDL had 21% greater water content than ISO, and HYPER had 17% less water content than ISO (p < 0.05). SOL HYPO resulted in higher phosphocreatine and lower lactate and creatine vs. HYPER (p < 0.05) but there were no differences in EDL between HYPO and HYPER. Pyruvate dehydrogenase activity increased in SOL HYPER vs. HYPO, whereas glycogen phosphorylase a increased in EDL HYPER vs. HYPO. In conclusion, fibre-type-specific responses exist after contraction such that when SOL muscle is perturbed in HYPER, as compared with HYPO, media, metabolic activity increases. Future work should focus on glucose uptake–regulation during anisosmotic conditions.
The C allele of the AGT Met235Thr polymorphism is associated with power sports performance
Authors: Gomez-Gallego Felix , Santiago Catalina , González-Freire Marta , Yvert Thomas , Muniesa Carlos A. , Serratosa Luis , Altmäe Signe , Ruiz Jonatan R. , Lucia Alejandro
Published: December 2009

Whether the Met235Thr (rs699) variation in the angiotensinogen (AGT) gene, encoding a threonine instead of a methionine in codon 235 of the mature protein, is associated with athletic performance remains to be elucidated. We compared the genotype and allele frequencies for the AGT Met235Thr variation (rs699) in 119 nonathletic controls, 100 world-class endurance athletes (professional cyclists, Olympic-class runners), and 63 power athletes (top-level jumpers, throwers, sprinters). Participants were all males and from the same descent (Caucasian) for ≥3 generations. The proportion of the CC genotype was significantly higher in the power group (34.9%) than in either the control (16%) or the endurance group (16%) (p = 0.008 and p = 0.005, respectively). The odds ratio (95% CI) of being a power athlete if the subject has a CC genotype was 1.681 (1.176–2.401), compared with the control group. In summary, the C allele of the AGT Met235Thr polymorphism might favour power sports performance. Although more research is needed, this could be attributed to the higher activity of angiotensin II, a skeletal muscle growth factor.
Effects of ingesting a commercial thermogenic product on hemodynamic function and energy expenditure at rest in males and females
Authors: Wilborn Colin , Taylor Lem , Poole Chris , Bushey Brandon , Williams Laura , Foster Cliffa , Campbell Bill
Published: December 2009

The purpose of this study was to examine the effects of a commercially available thermogenic product (TP) on resting energy expenditure (REE) and hemodynamic variables in a randomized, double-blind, placebo (PL)-controlled study. Eight male (age: 23.0 ± 3.70 years, weight: 95.77 ± 16.44 kg, height: 182.4 ± 7.87 cm) and 10 female (age: 23.6 ± 4.81 years, weight: 67.25 ± 5.74 kg, height: 172.42 ± 10.31 cm) physically active individuals participated in this study. Participants reported to the laboratory on a 10-h fast and performed baseline testing on REE, heart rate, and blood pressure. Participants were then randomly assigned to ingest 3 capsules of either an experimental TP or a vitamin E PL. Criterion variables were then measured at 1-, 2-, and 3-h post ingestion. Data were analyzed by 2-factor analysis of variance (ANOVA) using SPSS, version 16.0 (SPSS Inc., Chicago, Ill.). Supplementation of the TP resulted in a significant main effect for time (p = 0.040) and for interaction (p < 0.01) in REE when compared with PL. Post hoc analysis revealed that there was no significant difference (p > 0.05) between groups at baseline, but the TP group was significantly higher (p < 0.01) than the PL group at 1-, 2-, and 3-h post, with peak values being achieved at 2-h post time point. The TP group also experienced an overall increase in REE by 17.3%, 19.6%, and 15.3% at the 1-, 2-, and 3-h time points, respectively, over baseline values. Conversely, the PL group experienced a reduction in REE by 2.5%, 1.8%, and 0.3% at the same time points compared with baseline values. There was no significant change in heart rate, systolic blood pressure, or diastolic blood pressure in either group. Taken on a daily basis, a TP may increase overall energy expenditure. Caloric expenditure significantly increased at all 3 time points in the TP group, whereas the PL group experienced no change in energy expenditure.
Protective effect of resveratrol on formation of membrane protein carbonyls and lipid peroxidation in erythrocytes subjected to oxidative stress
Authors: Pandey Kanti Bhooshan , Rizvi Syed Ibrahim
Published: December 2009

Many of the biological actions of resveratrol have been attributed to its antioxidant properties. In this work, we subjected human erythrocytes to in vitro oxidative stress by incubating them with tert-butylhydroperoxide (t-BHP). This caused a significant increase in the malondialdehyde (MDA) level and the protein carbonyl group content above the basal values. The presence of trans-resveratrol at micromolar concentrations in the incubation medium protected the erythrocytes from t-BHP-induced oxidative stress, as evidenced by the decrease in the MDA level and the protein carbonyl group content. The effect of resveratrol was concentration and time-dependent. Our findings help to explain some of the beneficial effects of resveratrol.