bluuebunny/crossref_metadata_2025 huggingface dataset:
Retinal vascular events after intravitreal bevacizumab
Authors: Mansour Ahmad M. , Bynoe Leon A. , Welch John C. , Pesavento Richard , Mahendradas Padmamalini , Ziemssen Focke , Pai Sivakami A.
Published: December 2009

Acta Ophthalmol. 2010: 88: 730–735

Purpose:  To record retinal vascular events following intravitreal bevacizumab injection.

Methods:  Collaborative multi‐centre retrospective case series.

Results:  Eight patients were documented to have central retinal artery occlusion (four patients), branch retinal artery occlusion, capillary occlusion, central retinal vein occlusion and branch retinal vein occlusion (one patient each) within 0–55 days (median 2 weeks) of intravitreal bevacizumab. All patients had several ocular and systemic risk factors for retinal vascular events: elevated intraocular pressure on discharge (four patients), pre‐existent glaucoma (one patient), pre‐existent ischaemic retinal vascular disorder (four patients), systemic hypertension (five patients), diabetes mellitus (three patients), coronary artery disease (four patients), carotid disease (three patients), smoking (two patients) and migraine (one patient).

Conclusion:  The retinal vascular events may be associated with the underlying ocular disease under treatment or with the underlying systemic disease, may be related to an increased intraocular pressure post‐injection constraining further an already poor retinal perfusion, the vasoconstrictor effect of bevacizumab, or a combination of all three.
Timing of uveitis onset in oligoarticular juvenile idiopathic arthritis (JIA) is the main predictor of severe course uveitis
Authors: Zannin Maria E. , Buscain Irene , Vittadello Fabio , Martini Giorgia , Alessio Maria , Orsoni Jelka G. , Breda Luciana , Rigante Donato , Cimaz Rolando , Zulian Francesco
Published: December 2009

Purpose:  Aim of the present study was to validate a statistical model to predict a severe course of anterior uveitis (AU) in patients with juvenile idiopathic arthritis (JIA).

Methods:  Consecutive patients with newly diagnosed uveitis have been followed for at least 1 year with a standardized protocol. For each patient, demographic, clinical and laboratory characteristics, including time interval between arthritis and uveitis onset, α2‐globulins level at arthritis onset, number of uveitis relapses/year, ocular complications and therapy and visual acuity, have reported. The validation procedure included the assessment of sensitivity, specificity and efficiency of previously published statistical model (Zulian et al. J Rheumatol 2002; 29: 2446–2453) in a new inception cohort of patients during a short length follow‐up.

Results:  Sixty patients with JIA, followed at 14 paediatric rheumatology–ophthalmology centres in Italy, entered the study. The mean age at arthritis onset was 4.4 years (range 1.2–15.8 years), and the mean interval time between arthritis and uveitis onset was 1.8 years (range: 0.0–14.2 years). After the first AU, patients, followed for a mean of 3.2 years, had a mean of 2.9 uveitis relapses. Twenty‐two patients (36.7%) presented at least one complication. Using a probability cut‐off value = 0.7, the statistical model revealed 80% sensitivity, 58% specificity and 65% efficiency.

Conclusion:  The time interval between arthritis and uveitis onset resulted as the main predictor of severe course uveitis in JIA. The statistical model was able to predict the development of a severe course in 8 of 10 patients.
Restoration of Normal Rotator Cuff Function after Successful Treatment of a Displaced Non-union of a Fracture of the Body of the Scapula
Authors: Mcgarvey Ciaran , Lambert Simon
Published: December 2009

No previous reports have identified the mechanical disadvantage created by scapular body fractures or quantified the improvement in cuff function achieved by restoration of the scapular anatomy. We report a displaced non-union of the scapular body in a veteran pentathlete with weakness and early fatigue of rotator cuff function. Electromyography and magnetic resonance imaging excluded denervation, tendon rupture or muscle scarring. Characteristic anteromedial displacement of the lateral column fragment caused shortening of the transverse diameter of the scapula and the effective length of cuff muscle. Isokinetic dynamometry quantified cuff weakness, particularly in internal rotation. Healing of the non-union was demonstrated following open reduction, internal fixation, and bone grafting. Isokinetic dynamometry quantified restoration of normal cuff function, and an excellent clinical outcome was achieved. We conclude that measurable deficits in cuff function may follow scapular body fractures. Operative management to union can restore normal scapular and rotator cuff function.
Optical emission spectroscopy as a tool for studying, optimizing, and monitoring plasma-assisted atomic layer deposition processes
Authors: Mackus A. J. M. , Heil S. B. S. , Langereis E. , Knoops H. C. M. , van de Sanden M. C. M. , Kessels W. M. M.
Published: December 2009

In this note it is demonstrated that optical emission spectroscopy (OES) is an easy-to-implement and valuable tool to study, optimize, and monitor thin film growth by plasma-assisted atomic layer deposition (ALD). The species in the plasma can be identified through the analysis of the light emitted by the plasma. OES provides therefore information on the reactant species delivered to the surface by the plasma but it also yields unique insight into the surface reaction products and, as a consequence, on the reaction mechanisms of the deposition process. Time-resolved measurements reveal information about the amount of precursor dosing and length of plasma exposure needed to saturate the self-limiting half reactions, which is useful for the optimization of the ALD process. Furthermore, time-resolved OES can also be used as an easy-to-implement process monitoring tool for plasma-assisted ALD processes on production equipment; for example, to monitor reactor wall conditions or to detect process faults in real time.
Influence of oxygen partial pressure on microstructure and discharge properties of Mg–Zr–O protective films deposited by magnetron sputtering
Authors: Wang Jianfeng , Wu Huiyan , Song Zhongxiao , Li Yanhuai , Xu Kewei , Liu Chunliang
Published: December 2009

Mg–Zr–O protective films for plasma display panels were deposited on soda-lime glass substrates by magnetron sputtering. The effects of oxygen partial pressure on both the discharge properties (i.e., firing voltage Vf, minimum sustaining voltage Vs, and memory coefficient MC) and the microstructure of the Mg–Zr–O films were investigated. The results show that the deposited Mg–Zr–O films retain the NaCl-type structure as the pure MgO crystal and the doped Zr exists in the form of Zr4+ substitutional solid solution in MgO crystal lattice. The grain of the films is very fine and the mean grain size is about 7nm. As the oxygen partial pressure increases from 0.06to0.12Pa, the Zr content increases and surface roughness of the films decreases. However, when oxygen partial pressure further increases, the film shows a decrease in Zr content and an increase in surface roughness. At oxygen partial pressure of 0.12Pa, the Mg–Zr–O film has the lowest Vf and Vs and the largest MC, exhibiting the best discharge properties. The improvement of the discharge properties is thought to be related to the energy-band structure and the surface conditions of the Mg–Zr–O films.
Multilayer high reflectance coating on polyethylene terephthalate film consisting of Ag/SiO2/TiO2 layers that are not quarter-wave thickness
Authors: Koike Katsuhiko , Shimada Koichi , Fukuda Shin
Published: December 2009

A multilayer high reflectance coating consisting of Ag, SiO2, and TiO2 with Rvis of 99.3% was successfully designed by simulation based on Maxwell’s equations. The authors found that providing the low refractive index SiO2 layer with non-quarter-wave thickness (0.14 of nd/λ for 550 nm light) near the Ag layer made a leading contribution to this high reflectance. They successfully made a multilayer high reflectance coating of Ag/SiO2/TiO2 on polyethylene telephthalate film with Rvis of 99.4% based on that simulation. A backlight unit with a coating of Ag/SiO2/TiO2 exhibited high luminance 1.04 times that of Ag alone. Ag atoms are mixed with Si atoms upon deposit of a SiO2 layer on Ag in an atmosphere with O2. A SiO2–P layer deposited under O2 free conditions from a SiO2 ceramic target and a TiOx layer deposited from Ti work well for protection of the Ag layer from oxidation upon deposit of SiO2.
Fibrinogen Regulates the Cytotoxicity of Mycobacterial Trehalose Dimycolate but Is Not Required for Cell Recruitment, Cytokine Response, or Control of Mycobacterial Infection
Authors: Sakamoto Kaori , Geisel Rachel E. , Kim Mi-Jeong , Wyatt Bryce T. , Sellers Llewelyn B. , Smiley Stephen T. , Cooper Andrea M. , Russell David G. , Rhoades Elizabeth R.
Published: December 2009

During inflammatory responses and wound healing, the conversion of soluble fibrinogen to fibrin, an insoluble extracellular matrix, long has been assumed to create a scaffold for the migration of leukocytes and fibroblasts. Previous studies concluded that fibrinogen is a necessary cofactor for mycobacterial trehalose 6,6′-dimycolate-induced responses, because trehalose dimycolate-coated beads, to which fibrinogen was adsorbed, were more inflammatory than those to which other plasma proteins were adsorbed. Herein, we investigate roles for fibrin(ogen) in anin vivomodel of mycobacterial granuloma formation and in infection withMycobacterium tuberculosis, the causative agent of tuberculosis. In wild-type mice, the subcutaneous injection of trehalose dimycolate-coated polystyrene microspheres, suspended within Matrigel, elicited a pyogranulomatous response during the course of 12 days. In fibrinogen-deficient mice, neutrophils were recruited but a more suppurative lesion developed, with the marked degradation and disintegration of the matrix. Compared to that in wild-type mice, the early formation of granulation tissue in fibrinogen-deficient mice was edematous, hypocellular, and disorganized. These deficiencies were complemented by the addition of exogenous fibrinogen. The absence of fibrinogen had no effect on cell recruitment or cytokine production in response to trehalose dimycolate, nor was there a difference in lung histopathology or overall bacterial burden in mice infected withMycobacterium tuberculosis. In this model, fibrin(ogen) was not required for cell recruitment, cytokine response, or response to infection, but it promoted granulation tissue formation and suppressed leukocyte necrosis.
Extracts of the Rat Tapeworm,Hymenolepis diminuta, Suppress Macrophage ActivationIn Vitroand Alleviate Chemically Induced Colitis in Mice
Authors: Johnston M. J. G. , Wang A. , Catarino M. E. D. , Ball L. , Phan V. C. , MacDonald J. A. , McKay D. M.
Published: December 2009

Analysis of parasite-host interactions can reveal the intricacies of immunity and identify ways to modulate immunopathological reactions. We assessed the ability of a phosphate-buffered saline-soluble extract of adultHymenolepis diminutato suppress macrophage (human THP-1 cell line, murine peritoneal macrophages) activityin vitroand the impact of treating mice with this extract on colitis induced by dinitrobenzene sulfonic acid (DNBS). A high-molecular-mass fraction of adultH. diminuta(HdHMW) or excretory/secretory products reduced macrophage activation: lipopolysaccharide (LPS)-induced interleukin-1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α) and poly(I:C)-induced TNF-α and IL-6 were suppressed byHdHMW. The active component in theHdHMW extract was minimally sensitive to boiling and trypsin digestion, whereas the use of sodium metaperiodate, as a general deglycosylation strategy, indicated that the immunosuppressive effect ofHdHMW was at least partially dependent on a glycan: treating theHdHMW with neuraminidase and α-mannosidase failed to inhibit its blockade of LPS-induced TNF-α production by THP-1 macrophages. Mice treated with DNBS developed colitis, as typified by wasting, shortening of the colon, macroscopic and microscopic tissue damage, and an inflammatory infiltrate. Mice cotreated withHdHMW (three intraperitoneal injections) displayed significantly less inflammatory disease, and this was accompanied by reduced TNF-α production and increased IL-10 and IL-4 production by mitogen-stimulated spleen cells. However, cotreatment of mice with neutralizing anti-IL-10 antibodies had only a minor impact on the anticolitic effect of theHdHMW. We speculate that purification of the immunosuppressive factor(s) fromH. diminutahas the potential to lead to the development of novel immunomodulatory drugs to treat inflammatory disease.
The Science of Salsa: Antimicrobial Properties of Salsa Components to Learn Scientific Methodology
Authors: Marsh Tamara L. , Arriola Paul E.
Published: December 2009

Most ethnic foods and cooking practices have incorporated the use of spices and other food additives. Many common spices have crossed cultural boundaries and appear in multiple ethnic cuisines. Recent studies have demonstrated that many of these ingredients possess antimicrobial properties against common food spoilage microorganisms. We developed a laboratory exercise that promotes the use of scientific methodology to evaluate the effectiveness of salsa components at inhibiting the growth of undesirable microorganisms. Tomato, onion, garlic, cilantro, and jalapeño were tested for antimicrobial properties against a representative fungus,
Saccharomyces cerevisiae
, and the common food spoilage bacteria
Staphylococcus aureus
,
Bacillus cereus
, and
Escherichia coli
. Each component was ethanol extracted and a modification of the Kirby-Bauer method of antimicrobial sensitivity was employed. Garlic demonstrated the greatest inhibitory effects against all organisms tested. Onion demonstrated a slight inhibition of all four organisms, while cilantro showed some inhibition of all three bacteria but no effect against the fungus. Jalapeño may have slightly inhibited
E. coli
and
S. aureus
, as evidenced by a consistently measured increase in the zone of inhibition that was not statistically significant when compared to that of the control. Following the initial exercise, students were given the opportunity to repeat the exercise using other spices such as cinnamon, clove, nutmeg, and coriander. Student learning outcomes were evaluated using preliminary and secondary surveys, mainly focusing on definitions of science and hypothesis as well as the process of science. Students enjoyed this exercise and met the learning goals of understanding the process and methodology of science, as well as the interdisciplinarity inherent in the sciences. Student learning was evidenced by an increase in the number of correct responses on the secondary survey in comparison to the preliminary.
The Undergraduate Teaching Assistant Experience Offers Opportunities Similar to the Undergraduate Research Experience
Authors: Schalk Kelly A. , McGinnis J. Randy , Harring Jeffrey R. , Hendrickson Amy , Smith Ann C.
Published: December 2009

There has been a growing concern in higher education about our failure to produce scientifically trained workers and scientifically literate citizens. Active-learning and research-oriented activities are posited as ways to give students a deeper understanding of science. We report on an undergraduate teaching assistant (UTA) experience and suggest that students who participate as a UTA obtain benefits analogous to those who participate as an undergraduate research assistant (URA). We examined the experiences of 24 undergraduates acting as UTAs in a general microbiology course. Self-reported gains by the UTAs were supported by observational data from undergraduates in the course who were mentored by the UTAs and by the graduate teaching assistants (GTAs) with whom the UTAs worked. Specifically, data from the UTAs’ journals and self-reported Likert scales and rubrics indicated that our teaching assistants developed professional characteristics such as self-confidence and communication and leadership skills, while they acquired knowledge of microbiology content and laboratory skills. Data from the undergraduate Likert scale as well as the pre- and post-GTA rubrics further confirmed our UTA’s data interpretations. These findings are significant because they offer empirical data to support the suggestion that the UTA experience is an effective option for developing skills and knowledge in undergraduates that are essential for careers in science. The UTA experience provides a valuable alternative to the URA experience.
Impact of Online Learning Modules on Medical Student Microbiology Examination Scores
Authors: Johnson Mary T.
Published: December 2009

Medical students have a limited amount of time in which to acquire working knowledge of an enormous amount of information, and this is especially relevant for microbiology. One large midwestern medical school is unique in having medical microbiology taught at nine regional campuses using a single core curriculum. A committee of statewide course directors writes a licensure board-style final examination that is referenced to the core and used at all campuses. To prepare for the final examination, students traditionally utilize print-based board examination review books. The purpose of the present study was to determine whether students who train using web-based quizzes score differently as a group on this statewide examination than students who do not utilize the materials online for exam preparation. The study included 71 learners from two different campuses who were taught by the same instructor and were admitted to medical school with similar exemplary credentials. Results were aggregated for three consecutive years. A standard medical microbiology textbook was used to assign the same suggested readings for all students and similar laboratory sessions were provided for all learners. The independent variable was use of the web-based quizzes to prepare before examinations, as indicated by student web usage logs. The dependent variable was score on the statewide final examination. Results support the hypothesis that students who use preparation modules online score higher on the final examination than students who do not. Moreover, students who prepared online scored higher on questions designed to test synthesis of knowledge and analysis of data. The significant difference in final examination outcome (
P
< 0.002 using a two-tailed unpaired
t
test) indicates that online preparation for high-stakes examinations could improve student performance in medical microbiology.
The use of modern polarographic techniques in elucidation of reduction mechanisms of 1,3,5-triazine and pyridine herbicides on mercury electrodes
Authors: Rodríguez Mellado José Miguel
Published: December 2009

The application of differential pulse polarography to elucidation of the mechanisms of electroreduction of some heterocyclic herbicides is presented, showing that modern polarographic techniques are useful in fields different from electroanalysis. The methodology is briefly exposed and the results of its application to reduction of 1,3,5-triazine and pyridine herbicides are discussed.
Dieting to win or to be thin? A study of dieting and disordered eating among adolescent elite athletes and non-athlete controls
Authors: Martinsen M , Bratland-Sanda S , Eriksson A K , Sundgot-Borgen J
Published: December 2009

Objective:

To examine the prevalence of dieting, reasons for dieting and prevalence of disordered eating among adolescent elite athletes and age-matched controls, and to examine the differences between athletes competing in leanness and non-leanness sports.

Methods:

First-year students of 16 different Norwegian Elite Sport High Schools (athlete group, n = 682) and two randomly selected ordinary high schools from a county representative of the general Norwegian population (control group, n = 423) were invited to participate in this cross-sectional study. A total of 606 athletes and 355 controls completed the questionnaire, giving a response rate of 89% and 84%, respectively. The questionnaire contained questions regarding training patterns, menstrual status and history, dieting, use of pathogenic weight control methods and the drive for thinness (DT) and body dissatisfaction (BD) subscales from the Eating Disorders Inventory.

Main outcome measure:

Disordered eating, defined as meeting one or more of the following criteria: DT score ⩾15 (girls) and ⩾10 (boys), BD score ⩾14 (girls) and ⩾10 (boys), body mass index <17.9 kg/m2(girls) and <17.5 kg/m2(boys), current and/or ⩾3 previous efforts to lose weight, use of pathogenic weight control methods and self-reported menstrual dysfunction.

Results:

A higher prevalence of control subjects were dieting and classified with disordered eating compared with the athletes. An improvement of appearance was a more common reason for dieting among controls compared with athletes. No differences in dieting or disordered eating were found between leanness and non-leanness sports athletes.

Conclusions:

Self-reported disordered eating is more prevalent among controls than adolescent elite athletes, and losing weight to enhance performance is an important reason for dieting among adolescent elite athletes.
Correlation of autoantibodies and CD5+ B cells in ocular adnexal marginal zone B cell lymphomas
Authors: Kubota T , Moritani S , Yoshino T , Nagai H , Terasaki H
Published: December 2009

Aim:

To determine the clinicopathological properties of ocular adnexal marginal zone B cell lymphomas (MZBLs) with CD5+ B cells.

Methods:

This study determined the clinicopathological properties of MZBL samples from 97 patients with ocular adnexal MZBLs and searched for hallmarks of systemic autoimmunity in these patients.

Results:

Two elderly female patients were found to have ocular adnexal MZBLs with CD5+ B cells; flow cytometry analysis suggested that one of these MZBLs had CD5+ B cell clonal proliferation. The levels of anti-single stranded (SS)-DNA and anti-SS-A/Ro antibodies in these two patients were significantly higher than those in controls that were matched for age, gender and disease (2/2 versus 0/14; p = 0.008) and controls without MZBL (2/2 versus 0/30; p = 0.002). The genes from the immunoglobulin heavy-chain variable region for one of the patients showed a V3-21 segment. In addition, another patient with ocular adnexal reactive lymphoid hyperplasia with CD5+ B cells also had anti-SS-DNA antibodies.

Conclusion:

Patients with ocular adnexal MZBLs with CD5+ B cells may have a background of systemic conditions with CD5+ B-cell-related autoantibodies.
The right not to know and preimplantation genetic diagnosis for Huntington’s disease
Authors: Asscher E , Koops B-J
Published: December 2009

The right not to know is underappreciated in policy-making. Despite its articulation in medical law and ethics, policy-makers too easily let other concerns override the right not to know. This observation is triggered by a recent decision of the Dutch government on embryo selection for Huntington’s disease. This is a monogenetic debilitating disease without cure, leading to death in early middle age, and thus is a likely candidate for preimplantation genetic diagnosis (PGD). People possibly affected with the Huntington gene do not always want to know their genetic status themselves, which is very burdensome knowledge. For prospective parents, this creates a difficulty in having unaffected children through embryo selection without knowing their own genetic status. A solution is provided by the exclusion test: it allows embryo selection while honouring the parents’ right not to know. The Dutch government however disallowed the exclusion test and chose to allow PGD on Huntington only for parents who test themselves first. To avoid “unnecessary” in-vitro fertilisation procedures for unaffected parents, prospective parents are “forced to know” before they can conceive through embryo selection. This article analyses the scope of the right not to know in the context of embryo selection against Huntington’s disease. It concludes that the right not to know implies that PGD against Huntington should be allowed by means of the exclusion test.
A practical approach to teaching medical ethics
Authors: Mills S , Bryden D C
Published: December 2009

Teaching medical ethics and law has become much more prominent in medical student education, largely as a result of a 1998 consensus statement on such teaching. Ethics is commonly taught at undergraduate level using lectures and small group tutorials, but there is no recognised method for transferring this theoretical knowledge into practice and ward-based learning. This reflective article by a Sheffield university undergraduate medical student describes the value of using a student-selected component to study practical clinical ethics and the use of a clinical ethics checklist. The ethical checklist was proposed by Sokol as a tool for use by medical staff during the ward round to prompt the consideration of important ethical principles in relation to care. This paper describes additional uses for the checklist as a tool for teaching and learning about the practical application of ethical principles and for observing professional behaviours within a critical care and acute care environment. Evidence suggests that putting ethical behaviour into practice offers a far greater challenge to a newly qualified doctor than has been appreciated, and that more needs to be done at an undergraduate level to help combat this. This paper argues from a personal standpoint of an individual student experience that this can best be done in a clinical medical setting.
When physicians forego the doctor–patient relationship, should they elect to self-prescribe or curbside? An empirical and ethical analysis
Authors: Walter J K , Lang C W , Ross L F
Published: December 2009

Background:

The American Medical Association, the British Medical Association and the Canadian Medical Association have guidelines that specifically discourage physicians from self-prescribing or prescribing to family members, but only the BMA addresses informal prescription requests between colleagues.

Objective:

To examine the practices of paediatric providers regarding self-prescribing, curbsiding colleagues, and prescribing and refusing to prescribe to friends and family.

Methods:

1086 paediatricians listed from the American Academy of Paediatrics 2007 web-based directory were surveyed.

Results:

44% (430/982) of eligible survey respondents returned usable surveys. Almost half (198/407) of respondents had prescribed for themselves. An equal number (198/411) had informally requested a prescription from a colleague. Three-quarters (325/429) stated they had been asked to prescribe a prescription drug for a first-degree or second-degree relative, and 51% (186/363) had been asked by their spouse. Eighty-six per cent (343/397) stated that they had refused to write a prescription on at least one occasion for a friend or family member. The following reasons “strongly influenced” their decision to refuse a prescription request: (1) outside of provider’s expertise (88%); (2) patient’s need for his or her own physician (70%); (3) not medically indicated (69%); (4) need for a physical examination (65%).

Conclusion:

These data confirm that most physicians have engaged in self-prescribing or curbside requests for prescriptions. It can be argued that curbsiding is more morally problematic than self-prescribing because it implicates a third party, and should be discouraged regardless of whether the requester is a colleague, family member or friend.
Ni, Cu, Au, and platinum-group element contents of sulphides associated with intraplate magmatism: a synthesis
Authors: Barnes Sarah-Jane , Zientek M. L. , Severson M. J.
Published: December 2009

The tectonic setting of intraplate magmas, typically a plume intersecting a rift, is ideal for the development of Ni – Cu – platinum-group element-bearing sulphides. The plume transports metal-rich magmas close to the mantle–crust boundary. The interaction of the rift and plume permits rapid transport of the magma into the crust, thus ensuring that no sulphides are lost from the magma en route to the crust. The rift may contain sediments which could provide the sulphur necessary to bring about sulphide saturation in the magmas. The plume provides large volumes of mafic magma; thus any sulphides that form can collect metals from a large volume of magma and consequently the sulphides will be metal rich. The large volume of magma provides sufficient heat to release large quantities of S from the crust, thus providing sufficient S to form a large sulphide deposit. The composition of the sulphides varies on a number of scales: (i) there is a variation between geographic areas, in which sulphides from the Noril'sk–Talnakh area are the richest in metals and those from the Muskox intrusion are poorest in metals; (ii) there is a variation between textural types of sulphides, in which disseminated sulphides are generally richer in metals than the associated massive and matrix sulphides; and (iii) the massive and matrix sulphides show a much wider range of compositions than the disseminated sulphides, and on the basis of their Ni/Cu ratio the massive and matrix sulphides can be divided into Cu rich and Fe rich. The Cu-rich sulphides are also enriched in Pt, Pd, and Au; in contrast, the Fe-rich sulphides are enriched in Fe, Os, Ir, Ru, and Rh. Nickel concentrations are similar in both. Differences in the composition between the sulphides from different areas may be attributed to a combination of differences in composition of the silicate magma from which the sulphides segregated and differences in the ratio of silicate to sulphide liquid (R factors). The higher metal content of the disseminated sulphides relative to the massive and matrix sulphides may be due to the fact that the disseminated sulphides equilibrated with a larger volume of magma than massive and matrix sulphides. The difference in composition between the Cu- and Fe-rich sulphides may be the result of the fractional crystallization of monosulphide solid solution from a sulphide liquid, with the Cu-rich sulphides representing the liquid and the Fe-rich sulphides representing the cumulate.
Crystallization of sulfide liquids and the interpretation of ore composition
Authors: Ebel D. S. , Naldrett A. J.
Published: December 2009

We have been exploring ways to quantitatively assess the extent to which fractionation of sulfide melt has effected variations in composition within magmatic sulfide ore bodies. Our approach has been to determine by experiment the crystallization paths of sulfide liquids in temperature and composition dimensions. In this paper, the results of new major-element partitioning experiments below 1050 °C in the nickel-free system are presented and summarized along with new and previous work in the Fe–Ni–Cu–S quaternary. The partition coefficients D for Cu between monosulfid solid solution (mss) and sulfide liquid in the Ni-free system (DCu = (wt.% Cu in mss)/(wt.% Cu in liquid)) cluster near 0.3, but decrease to nearly 0.1 for Cu-rich, S-poor liquids near 1000 °C. DNi also declines with decreasing sulfur content of the liquid, but increases with decreasing temperature. Preliminary data indicate that DNi exceeds 1.0 in low-Ni liquids with greater than 16 wt.% Cu, at 1050 °C. The quality of available data on the Fe–Ni–Cu–S system currently exceeds the sensitivity of crystallization models based on the distribution coefficient approximation for major elements. However, we present equations for variable distribution coefficients for Ni and Cu that can be incorporated into calculations of the ratio of trapped initial liquid to fractionated solid for bulk ore samples, using D values for platinum group elements from the literature. Fractionation can then be modeled quite well using an iterative approach, with D values changing in response to liquid composition with each increment of crystallization along an assumed temperature path.
Magmatic unconformities and stratigraphic relations in the Peridotite zone, Stillwater Complex, Montana
Authors: Cooper Roger W.
Published: December 2009

New stratigraphic relations between cumulate layers and units are documented in the Peridotite zone of the Stillwater Complex, a late Archean mafic to ultramafic layered intrusion exposed along the northern edge of the Beartooth uplift, Montana. First, low-angle unconformities occur between all types of successive stratigraphic units and at all scales within the Peridotite zone. Second, new stratigraphic units and divisions, based on the unconformities and type of cumulate layering, within the Peridotite zone are proposed and are correlated with published stratigraphic columns. The stratigraphic units, identified on the basis of rock type(s) and contacts with adjacent units, from smallest to largest a cyclic units, multicyclic units, megacyclic groups, and subzones. The three larger units are usually bounded by low-angle magmatic unconformities. The three subzones and five of the six megacyclic groups identified in the Peridotite zone can be traced over a distance of 17.7 mi (28.3 km). The stratigraphic relations in the Peridotite zone indicate that low-angle crosscutting magmatic unconformities occur at all scales and that lateral variations within and between the identified stratigraphic units are common. The relations suggest an extremely dynamic and rapidly changing environment during formation of the Peridotite zone. Overprinted on the stratigraphic relations is a larger evolution of cumulus rock types in the Peridotite zone from more primitive stratigraphic units dominated by olivine and olivine–bronzite cumulates to more evolved stratigraphic units dominated by bronzite and bronzite–olivine cumulates. Several major magmatic, or possibly structural, events appear to have affected the Peridotite zone during its formation, as indicated by thickness-variation patterns in megacyclic groups and subzones. The thickest massive chromite layers in the Peridotite zone are associated with two of the major magmatic events.
Mantle temperature and lithospheric thinning beneath the Midcontinent rift system: evidence from magmatism and subsidence
Authors: White Robert S.
Published: December 2009

The tectono-magmatic history of the Midcontinent rift system can be explained by the presence of a mantle plume bringing elevated-temperature mantle beneath the rift system at about 1110 Ma. Huge volumes of extrusive and intrusive igneous rocks were generated as abnormally hot mantle decompressed beneath the lithospheric rift. Geochemical and isotopic data from the Keweenawan volcanics show that the earliest melts were derived from small-degree melting of primitive plume mantle, coupled with enriched metasomatic melts derived from the continental lithosphere. As rifting progressed, the main bulk of the volcanics was generated primarily from the plume mantle, with the melting starting at depths of about 120 km and extending to as shallow as the base of the stretched lithosphère at 45 km depth. Elevated mantle temperatures of 1500–1560 °C, approximately 150–200 °C above normal, are inferred from the rare earth element concentrations in the volcanic rocks. Further constraints on the mantle temperature come from combined subsidence and melt-generation modelling. I assume that rifting occurred in two main periods, during 1110–1105 and 1100–1094 Ma, with a reduced rate of stretching and greatly decreased melt production during the intervening period, 1105–1100 Ma. At the centre of the rift, production of more than 15 km of volcanic rocks close to, or above, sea level was followed by the accumulation of up to 8 km of mainly coarse terrigenous sediments in the postrift subsidence phase. This can be explained by lithospheric thinning by a factor of approximately 6 above mantle with a potential temperature of about 1550 °C. Subsequently, the mantle cooled to a normal potential temperature of 1350 °C as the plume thermal anomaly died away.
U – Th – Pb zircon ages of some Keweenawan Supergroup rocks from the south shore of Lake Superior
Authors: Zartman Robert E. , Nicholson Suzanne W. , Cannon William F. , Morey G. B.
Published: December 2009

New single-crystal zircon U–Th–Pb ages for plutonic and rhyolitic Keweenawan Supergroup rocks from the south shore of Lake Superior provide geochronological constraints on magmatic evolution associated with the 1.1 Ga Midcontinent rift. Analyses of a granophyric phase of the Mineral Lake intrusion and the Mellen granite, both parts of the Mellen Intrusive Complex, and a laterally extensive rhyolite from the top of the Kallander Creek Volcanics have weighted average 207Pb/206Pb ages of 1102.0 ± 2.8 Ma (N = 2), 1100.9 ± 1.4 Ma (N = 5), and 1098.8 ± 1.9 Ma (N = 4), respectively. Analyses of a pyroclastic rhyolite flow at the top of the Porcupine Volcanics result in variable 207Pb/206Pb ages that range from 1080 to 1137 Ma. This rhyolite exhibits a continuum between morphologically complex and simpler prismatic zircon crystals, the latter yielding concordant analyses having a weighted average 207Pb/206Pb age of 1093.6 ± 1.8 Ma (N = 2). Four prismatic zircons from an aphyric rhyolite of the Chengwatana Volcanics in the Ashland syncline form a linear array intersecting concordia at 1094.6 ± 2.1 Ma (MSWD = 1.3). Another presumed Chengwatana rhyolite recovered from drill core intersecting the Hudson–Afton horst in southeast Minnesota yielded only ~20 morphologically indistinguishable zircons. Six analyses give 207Pb/206Pb ages ranging from 1112 to 1136 Ma, including one analysis with a virtually concordant age of 1130 Ma. This age, however, is considerably older than that obtained for the Chengwatana Volcanics in the Ashland syncline or any other precisely dated rock from the Midcontinent rift.
Late-glacial climate and ecology of a kettle section at Brampton, Ontario, Canada, as determined from fossil Coleoptera
Authors: Motz John E. , Morgan Alan V.
Published: December 2009

A 5 m sequence of organic-rich sediments (ca. 13 000 years BP to ca. 4500 BP) from a drained glacial kettle pond near Brampton, Ontario, has yielded a rich and varied assemblage of coleopteran fossils. This paper discusses the beetles recovered from the basal 1 m of the section (ca. 13 000 to 12 500 BP), which represent the earliest phase of deposition in the kettle, prior to the final melt-out of underlying ice. The species are typical of northern boreal or tree-line habitats today. They illustrate that during this time the landscape was predominantly open ground, with herb and shrub vegetation. Individual trees or isolated clumps of conifers were nearby, as suggested by the presence of scolytids (bark beetles). The mean July temperature was in the range from 12.5 to 15 °C, indicating that the lack of trees is a lag effect in colonization, perhaps due to unsuitable substrate conditions rather than to an unfavourable climate.
U–Pb geochronologic constraints on the cover sequence of the Monashee complex, Canadian Cordillera: Paleoproterozoic deposition on basement
Authors: Crowley James L.
Published: December 2009

The cover sequence in the Monashee complex is a platformal metasedimentary succession that occupies a nearly unique position in the Canadian Cordillera due to its unconformable contact with exposed crystalline basement. Zircon U–Pb data and field observations show that the lower part of the sequence contains Paleoproterozoic rocks, the oldest known metasedimentary rocks in the Cordilleran miogeocline, and the upper part of the sequence is Mesoproterozoic or younger. Maximum age constraints on the lower part are provided by 1.99 Ga detrital zircons from the basal unit and a 1862 ± 1 Ma orthogneiss upon which it was presumably deposited. Minimum age constraints are provided by rocks that intruded into the lower part: 1852 ± 4 Ma pegmatite, 1762 ± 6 Ma leucogranite, and 724 ± 5 Ma syenitic gneiss. The upper part of the sequence must be considerably younger than the lower part because it contains a detrital zircon dated at ~1.21 Ga. Other detrital zircons, dated at Neoarchean (2.95–2.86 Ga) and Paleoproterozoic (1.85–1.81, 1.75 Ga), suggest a source in the western Canadian Shield. These ages constrain the thickness of Mesoproterozoic and Neoproterozoic metasedimentary rocks in the cover sequence to be < 2 km. Combining these ages with previously interpreted Paleozoic deposition ages for the middle and upper parts of the sequence constrains the thickness to be <0.2 km, considerably less than that of coeval rocks above the Monashee complex in the hanging wall of the Monashee décollement. Such a contrast suggests that deposition above and below the décollement occurred in different parts of the Cordilleran miogeocline.
Postglacial changes of terrestrial and marine environments along the Labrador coast: palynological evidence from cores 91-045-005 and 91-045-006, Cartwright Saddle
Authors: Levac Elisabeth , Vernal Anne de
Published: December 2009

The palynology of cores from Cartwright Saddle led to reconstruction of sea-surface conditions on the basis of transfer functions using dinoflagellate cyst assemblages, and to correlations with vegetational history on adjacent land as derived from pollen assemblages. From deglaciation to about 8000 BP, dinoflagellate cyst assemblages dominated by Algidasphaeridium? minutum indicate Arctic-type sea-surface conditions, and pollen assemblages reveal tundra vegetation in southeastern Labrador. Codominance of A.? minutum and Brigantedinium spp. indicate persistence of cold sea-surface conditions (August temperature < 3 °C) and extensive sea-ice cover (up to 11 months/year) until ca. 6000 BP. However, the occurrence of Abies, which reached a maximum abundance at ca. 7000–6000 BP, and increasing percentages of Alnus indicate northward tree migration and development of shrub tundra as a result of warmer terrestrial conditions. Around 6000 BP, the significant occurrence of Peridinium faeroense and Nematosphaeropsis labyrinthus suggests the establishment of modern-like conditions in surface waters. This transition coincides with an abrupt increase in the abundance of Picea, associated with the regional development of spruce forests. The later marine record does not indicate any significant trend in sea-surface temperature, whereas decreasing abundance of arboreal pollen reflects opening of the forest cover in response to a slight cooling onshore. Thus, palynological analyses suggest complex changes in continental climate and marine hydrography along the coast of Labrador.
Male and female rats with severe protein restriction present delayed wound healing
Authors: Otranto Marcela , Souza-Netto Isabel , Águila Márcia Barbosa , Monte-Alto-Costa Andréa
Published: December 2009

Malnutrition remains a significant problem, not only in developing countries, but also in the developed world. The aim of this study was to investigate the effects of protein restriction on rat excisional cutaneous healing. Male and female rats (12 weeks old) were exposed to different degrees of protein restriction (23%, 12% (slight restriction), and 0% (severe restriction)) for 12 weeks. On week 9, a full-thickness excisional skin lesion was performed, and the lesion area was measured to evaluate wound contraction and re-epithelialization. Euthanasia was performed after 12 weeks, and the lesion and adjacent skin were removed, fixed in formalin, and embedded in paraffin. Sections were stained with hematoxylin-eosin, toluidine blue, picro-mallory, and sirius red, and were immunostained for α-smooth muscle actin. Animals (males and females) exposed to severe protein restriction (0% protein) presented impairment of wound contraction. Inflammatory cells were present in higher amounts in the protein-restricted groups than in the 23% group. Extracellular matrix was poorly deposited in the severely restricted group (0%), but only mildly disturbed in the slightly restricted group (12%). Neovascularization was disturbed in both restricted groups. Our study demonstrates that animals exposed to slight protein restriction present disturbed wound healing, but animals exposed to severe protein restriction present impaired wound healing.
Slow postmeal walking reduces postprandial glycemia in middle-aged women
Authors: Nygaard Håvard , Tomten Sissel Erland , Høstmark Arne Torbjørn
Published: December 2009

Postprandial blood glucose concentration is a risk factor for the development of cardiovascular diseases and diabetes, even at states well below hyperglycemic levels. A previous study has shown that postmeal exercise of moderate intensity blunts the blood glucose increase after carbohydrate intake (Høstmark et al. Prev. Med. 42(5): 369–371). The objective of the present study was to examine whether even postmeal slow walking would have a similar effect. Fourteen healthy women aged >50 years participated in 3 experiments in a random crossover design: after a carbohydrate-rich meal, either they were seated (control experiment) or they performed slow postmeal walking for 15 min (W15) or 40 min (W40). Blood glucose concentration was determined prior to the meal (fasting), and at 11 time points throughout each experiment. The W15 trial lowered the blood glucose values during walking and delayed the peak blood glucose value (p = 0.003). In W40, the postmeal blood glucose increase during walking was blunted, the peak glucose value was delayed (p = 0.001), and the incremental area under the 2-h blood glucose curve (IAUC) was reduced (p = 0.014). There was a negative relationship between IAUC and walking time (p = 0.016). The individual reducing effect of walking on IAUC correlated strongly with IAUC on the control day (p < 0.001). We conclude that even slow postmeal walking can reduce the blood glucose response to a carbohydrate-rich meal. The magnitude of this effect seems to be related to the duration of walking and to the magnitude of the postprandial blood glucose response when resting after a carbohydrate-rich meal.
Bioaerosols in industrial environments: a reviewThis article is one of a selection of papers published in this Special Issue on Biological Air Treatment.
Authors: Gilbert Yan , Duchaine Caroline
Published: December 2009

Air quality in workplaces is a main concern for industrial hygienists and occupational health specialists. Aerosolization of microorganisms or their by-products from contaminated material can significantly decrease the air quality and expose the workers’ health to potentially harmful effects. To identify the risks and elaborate safe exposure thresholds, the microbiology of air samples from industrial workplaces must be characterized, which means the airborne microorganisms must be identified and quantified. This review summarizes, for nonbiologist specialists, the principal sampling and analysis techniques for air sample characterization regarding microbiological contamination. A survey of the literature regarding levels of airborne bacteria, fungi, and viruses in agricultural industries, waste management plants, peat and wood processing facilities, and other industries is also provided. This review shows that very complex bioaerosol sources are present in industrial settings, and variable and hardly predictable biodiversity is expected in such environments.