bluuebunny/crossref_metadata_2025 huggingface dataset:
Teaching information literacy skills to medical students: perceptions of health sciences librarians
Authors: Ullah Midrar , Ameen Kanwal
Published: October 2019

Background

This paper is the second part of a two phase, sequential mixed method study.

Objectives

To get the views of medical librarians in Pakistan regarding information literacy (IL) skills of medical students and how to teach them IL skills.

Methods

Structured interviews were conducted with 20 medical librarians in Pakistan. We audio recorded, transcribed all the interviews and performed content analysis and coding of the textual data. We presented the emerging themes with the frequency of their appearance.

Results

Interviewees agreed that the IL skills of their students were inadequate. Participants suggested that librarians should train students through mandatory IL instruction programmes, designed in coordination with medical faculty. However, workshops/seminars were considered the most effective IL delivery methods for medical faculty and clinicians. The majority of respondents supported the integration of IL instruction into the curriculum as an independent and credit course.

Discussion

Teaching IL skills to medical students requires proper planning. Therefore, librarians have to prove their place within the curricular structure of the institution and develop understanding of the pedagogy of instruction.

Conclusion

Librarians must collaborate with faculty to train students in advanced information skills. There is a need to integrate IL instruction into the curriculum at all levels.
Post‐exposure prophylaxis for HIV infection in sexual assault victims
Authors: Inciarte A , Leal L , Masfarre L , Gonzalez E , Diaz‐Brito V , Lucero C , Garcia‐Pindado J , León A , García F ,   the Sexual Assault Victims Study Group
Published: October 2019

Objectives

Sexual assault (SA) is recognized as a public health problem of epidemic proportions. Guidelines recommend the administration of post‐exposure prophylaxis (PEP) after an SA. However, few data are available about the feasibility of this strategy, and this study was conducted to assess this.

Methods

We conducted a retrospective, longitudinal, observational study in SA victims attending the Hospital Clinic in Barcelona from 2006 to 2015. A total of 1695 SA victims attended the emergency room (ER), of whom 883 met the PEP criteria. Five follow‐up visits were scheduled at days 1, 10, 28, 90 and 180 in the out‐patient clinic. The primary endpoint was PEP completion rate at day 28. Secondary endpoints were loss to follow‐up, treatment discontinuation, occurrence of adverse events (AEs) and rate of seroconversion.

Results

The median age of participants was 25 years [interquartile range (IQR) 21–33 years] and 93% were female. The median interval between exposure and presentation at the ER was 13 h (IQR 6–24 h). The level of risk was appreciable in 47% (n = 466) of individuals. Of 883 patients receiving PEP, 631 lived in Catalonia. In this group, the PEP completion rate at day 28 was 29% (n = 183). The follow‐up rate was 63% (n = 400) and 38% (n = 241) at days 1 and 28, respectively. Treatment discontinuation was present in 58 (15%) of 400 patients who attended at least the day 1 visit, the main reason being AEs (n = 35; 60%). AEs were reported in 226 (56%) patients, and were mainly gastrointestinal (n = 196; 49%). Only 211 (33%) patients returned for HIV testing at day 90. A single seroconversion was observed in a men who have sex with men (MSM) patient at day 120.

Conclusions

Follow‐up and compliance rates in SA victims were poor. In addition, > 50% of the patients experienced AEs, which were the main reason for PEP interruption. Strategies to increase follow‐up testing and new better tolerated drug regimens must be investigated to address these issues.
Results of a survey of cancer patients’ willingness to travel to participate in a clinical trial
Authors: Zdenkowski Nicholas , Lynam James , Sproule Victoria , Wall Laura , Searston Jessica , Brown Scott
Published: October 2019

Only 2–3% of cancer patients enrol in a trial. We surveyed patients' willingness to change clinician or treating centre, or to travel, to participate in trials, to improve trial recruitment. Of 188 respondents, 79% were willing to participate in a trial in at least one scenario. Increasing travel time, change in oncologist, private health insurance and out of pocket expenses decreased likelihood of joining a trial. Rural and regional patients, and those from lower socio‐economic areas, were more willing to travel. To optimise access to trials, clinicians should refer within and between institutions.
Bi‐modified SrTiO3‐based ceramics for high‐temperature energy storage applications
Authors: Kong Xi , Yang Letao , Cheng Zhenxiang , Zhang Shujun
Published: October 2019

Dielectric capacitors with high energy storage performance are in great demand for emerging advanced energy storage applications. Relaxor ferroelectrics are one type dielectric materials possessing high energy storage density and energy efficiency simultaneously. In this study, 0.9(Sr0.7Bi0.2)TiO3–0.1Bi(Mg0.5Me0.5)O3 (Me = Ti, Zr, and Hf) dielectric relaxors are designed and the corresponding energy storage properties are investigated. The excellent recoverable energy density of 3.1 J/cm3 with a high energy efficiency of 93% is achieved at applied electric field of 360 kV/cm for 0.9(Sr0.7Bi0.2)TiO3–0.1Bi(Mg0.5Hf0.5)O3 (0.9SBT–0.1BMH) ceramic. High breakdown strength of 460 kV/cm in 0.9SBT–0.1BMH ceramic is obtained by Weibull distribution with satisfied reliability. In addition, 0.9SBT–0.1BMH shows outstanding thermal stability of energy storage performance up to 200°C, with the variation being less than 5%, together with satisfying cycling stability and high charge‐discharge rate, making the 0.9SBT–0.1BMH ceramic a potential lead‐free candidate for high power energy storage applications at elevated temperature.
Higher expression of SATB2 in hepatocellular carcinoma of African Americans determines more aggressive phenotypes than those of Caucasian Americans
Authors: Yu Wei , Roy Sanjit K. , Ma Yiming , LaVeist Thomas A. , Shankar Sharmila , Srivastava Rakesh K.
Published: October 2019

In the United States, Hepatocellular Carcinoma (HCC) incidence has tripled over the past two decades. The disease has disproportionately affected minority and disadvantaged populations. The purpose of this study was to examine the expression of SATB2 gene in HCC cells derived from African Americans (AA) and Caucasian Americans (CA) and assess its oncogenic potential by measuring cell viability, spheroid formation, epithelial‐mesenchymal transition (EMT), stem cell markers and pluripotency maintaining factors in cancer stem cells (CSCs). We compared the expression of SATB2 in human primary hepatocytes, HCC cells derived from AA and CA, and HCC CSCs. Hepatocellular carcinoma cells derived from AA expressed the higher level of SATB2 than those from CA. By comparison, normal human hepatocytes did not express SATB2. Higher expression of SATB2 in HCC cells from AA was associated with greater growth rate, cell viability, colony formation and EMT characteristics than those from CA. Knockout of SATB2 in CSCs by Crispr/Cas9 technique significantly inhibited the expression of SATB2 gene, stem cell markers (CD24, CD44 and CD133), pluripotency maintaining factors (c‐Myc, KLF4, SOX2 and OCT4), and EMT compared with non‐targeting control group. The expression of SATB2 was negatively correlated with miR34a. SATB2 rescued the miR‐34a‐mediated inhibition of CSC's viability. These data suggest that SATB2 is an oncogenic factor, and its higher expression may explain the disparity in HCC outcomes among AA.
Astilbin prevents bone loss in ovariectomized mice through the inhibition of RANKL‐induced osteoclastogenesis
Authors: Jin Haiming , Wang Qingqing , Chen Kai , Xu Ke , Pan Hao , Chu Feifan , Ye Zhen , Wang Ziyi , Tickner Jennifer , Qiu Heng , Wang Chao , Kenny Jacob , Xu Huazi , Wang Te , Xu Jiake
Published: October 2019

Osteoporosis is the most common osteolytic disease characterized by excessive osteoclast formation and resultant bone loss, which afflicts millions of patients around the world. Astilbin, a traditional herb, is known to have anti‐inflammatory, antioxidant and antihepatic properties, but its role in osteoporosis treatment has not yet been confirmed. In our study, astilbin was found to have an inhibitory effect on the RANKL‐induced formation and function of OCs in a dose‐dependent manner without cytotoxicity. These effects were attributed to its ability to suppress the activity of two transcription factors (NFATc1 and c‐Fos) indispensable for osteoclast formation, followed by inhibition of the expression of bone resorption‐related genes and proteins (Acp5/TRAcP, CTSK, V‐ATPase‐d2 and integrin β3). Furthermore, we examined the underlying mechanisms and found that astilbin repressed osteoclastogenesis by blocking Ca2+ oscillations and the NF‐κB and MAPK pathways. In addition, the therapeutic effect of MA on preventing bone loss in vivo was further confirmed in an ovariectomized mouse model. Therefore, considering its ability to inhibit RANKL‐mediated osteoclastogenesis and the underlying mechanisms, astilbin might be a potential candidate for treating osteolytic bone diseases.
Oral hygiene revisited. The clinical effect of a prolonged oral hygiene phase prior to periodontal therapy in periodontitis patients. A randomized clinical study
Authors: Preus Hans R. , AL‐Lami Qamar , Baelum Vibeke
Published: October 2019

Aim

The aim of the present study was to investigate the effect of a 3‐month strict oral hygiene phase on key parameters of periodontitis: plaque, bleeding on probing (BOP) and probing pocket depth (PPD).

Materials and Methods

Forty‐four patients with severe periodontal disease were randomly allocated to a test or a control group. The test group completed a 3‐month strict oral hygiene phase. The control group did not receive any instructions or motivation on oral hygiene until after the 3‐month period. Plaque, BOP and PPDs were registered on four sites of each tooth at baseline and after 3 months in both groups, as well as after the postponed hygiene phase in the control group.

Results

A statistically significant and profound reduction in plaque, BOP and PPD was observed after the 3 months in the test group. No change to the better occurred in the control group.

Conclusion

A 3‐month strict oral hygiene phase in patients referred for periodontal therapy reduced plaque, BOP and pocket depth to such an extent that it could affect therapy planning.
Evolutionary Origin and Host Range of Plagiotoma lumbrici (Ciliophora, Hypotrichia), an Obligate Gut Symbiont of Lumbricid Earthworms
Authors: Obert Tomáš , Vďačný Peter
Published: October 2019

Four common earthworm species, the anecic Lumbricus terrestris, the endogeic Octolasion tyrteum as well as the epigeic Eisenia fetida and Dendrobaena veneta, were examined for the presence of the microbial gut symbiont Plagiotoma lumbrici. The evolutionary origin of this endobiotic microbe was reconstructed, using the 18S rRNA gene, the ITS1‐5.8S‐ITS2 region, and the first two domains of the 28S rRNA gene. Plagiotoma lumbrici was exclusively detected in the anecic Lumbricus terrestris. Multigene analyses and the ITS2 secondary structure robustly determined the phylogenetic home of Plagiotoma lumbrici populations within the oxytrichid Dorsomarginalia (Spirotrichea: Hypotrichia) as a sister taxon of the free‐living Hemiurosomoida longa. This indicates that earthworms obtained their gut endosymbiont by ingesting soil/leaf litter containing oxytrichine ciliates that became adapted to the intestinal tract of earthworms. Interestingly, according to the literature data, Plagiotoma lumbrici was detected in multiple anecic and some epigeic but never in endogeic earthworms. These observations suggest that Plagiotoma lumbrici might be adapted to certain gut conditions and the lifestyle of anecic Lumbricidae, such as Lumbricus, Aporrectodea, and Scherotheca, as well as of some co‐occurring epigeic Lumbricus species.
Tolerance of soya lecithin in children with non‐immunoglobulin E‐mediated soya allergy: a randomised, double‐blind, cross‐over trial
Authors: Gholmie Y. , Lozinsky A.C. , Godwin H. , Reeve K. , Dzubiak R. , Shah N. , Meyer R.
Published: October 2019

Background

Soya lecithin is present in a wide variety of foods regularly consumed by children, in the form of an emulsifier or stabiliser. Children with non‐immunoglobulin (Ig)E‐mediated allergies who commonly have to avoid milk and soya will have a significantly restrictive diet with reduced alternative foods if soya lecithin also has to be eliminated. The present study aimed to establish whether children with non‐IgE‐mediated gastrointestinal soya allergy react to soya lecithin in food products.

Methods

A double‐blind, cross‐over study was performed in soya‐allergic children aged between 8 months and 5 years. Eligible children had their soya allergy status confirmed with a home challenge. Children were randomly assigned to either placebo or challenge dose of soya lecithin (1.5 g per day) in a custom‐made biscuit. This was followed by a 1‐week washout period and cross‐over to another 1 week of challenge or placebo dose. Symptoms were recorded prior to commencing the study and at the end of each week’s challenge.

Results

Twenty‐two children, 16 boys, with a median age of 44 months (range 21–58 months) were recruited, although only 20 completed the full study. The median number of foods avoided in addition to soya was 3. Over the challenge period, the parents reported reactions in six cases: five cases (23%) to the placebo and one case (5%) to the challenge dose. There was no statistical difference (P = 0.025) between the groups.

Conclusions

One child with a non‐IgE‐mediated gastrointestinal allergy had a slight reaction to soya lecithin. Although single cases may react to soya lecithin, we suggest that soya lecithin should be included in children with this delayed allergy, unless they have a confirmed reaction to traces of soya within this emulsifier.
Increased pro‐collagen 1, elastin, and TGF‐β1 expression by copper ions in an ex‐vivo human skin model
Authors: Ogen‐Shtern Navit , Chumin Katerina , Cohen Guy , Borkow Gadi
Published: October 2019

Background

Clinical studies demonstrated that continued exposure to copper oxide–embedded textiles, such as pillowcases, significantly reduces depth of facial wrinkles and skin sagging and enhances skin elasticity.

Objective

Study the mechanisms by which the exposure to copper ions improve the well‐being of the skin.

Methods

Human skin explants, cultured ex‐vivo, were exposed topically to saline alone or saline containing 0.02 or 1 µmol/L copper ions. The skin explants viability, histology and secretion of elastin, pro‐collagen 1, and TGF‐β1 to the culture medium were determined at various time intervals.

Results

Exposure to saline containing 0.02 or 1 µmol/L copper ions did not affect the viability or morphological profile of the explants as compared to control explants treated with saline only. Notably, exposure of the skin grafts to 0.02 or to 1 µmol/L of copper ions resulted in ~100% and ~20% increases in elastin and pro‐collagen 1 concentrations, respectively, in the culture supernatants already after 1 day of incubation, which remained statistically significantly elevated also after 6 days on incubation, as compared to the control explants. In addition, ~2‐ and ~4‐fold increases in TGF‐ß1 levels in the culture supernatants of explants exposed to the copper ions were detected after 4 and 6 days of culture, as compared to the explants exposed to saline alone.

Conclusion

This study substantiated the anti‐aging effect that copper ions have on the skin and gave insights into the mechanisms by which exposure of the skin to copper ions improves the skin well‐being.
Leisure‐time physical activity and life expectancy in people with cardiometabolic multimorbidity and depression
Authors: Chudasama Y. V. , Zaccardi F. , Gillies C. L. , Dhalwani N. N. , Yates T. , Rowlands A. V. , Davies M. J , Khunti K.
Published: October 2019

Background

Whether and to what extent leisure‐time physical activity at the recommended levels of 150‐min moderate activity is associated with survival in people with cardiometabolic multimorbidity and depression is unknown.

Methods

UK Biobank participants were classified into groups: (i) no disease; (ii) diabetes; (iii) cardiovascular disease (CVD); (iv) depression; (v) diabetes and CVD; (vi) diabetes and depression; (vii) CVD and depression; (viii) diabetes, CVD and depression. Leisure‐time physical activity was categorized as active (meeting recommendations) or inactive. Survival models were applied to estimate life expectancy.

Results

A total of 480 940 participants were included (median age, 58 years; 46% men; 95% white), of whom 74% with cardiometabolic multimorbidity and depression were inactive. During a mean follow‐up of 7 years, 11 006 deaths occurred. At age of 45 years, being physically active was associated with 2.34 (95% confidence interval: 0.93, 3.54) additional years of life compared with being inactive in participants with diabetes; corresponding estimates were 2.28 (1.40, 3.16) for CVD; 2.15 (0.05, 4.26) for diabetes and CVD; and 1.58 (1.27, 1.89) for no disease. Participants with a combination of diabetes, CVD and depression, being active was associated with 6.81 (−1.50, 15.31) additional years compared with being inactive; corresponding estimates were 3.07 (−2.46, 8.59) for diabetes and depression; 2.34 (−1.24, 5.91) for CVD and depression; and 0.80 (−0.46, 2.05) for depression. A similar pattern was found at 65 years.

Conclusions

Meeting the recommended level of physical activity was associated with a longer life expectancy in people with cardiometabolic multimorbidity but not in those with depression.
CD36 expression on oral squamous cell carcinoma cells correlates with enhanced proliferation and migratory activity
Authors: Sakurai Kotaro , Tomihara Kei , Yamazaki Manabu , Heshiki Wataru , Moniruzzaman Rohan , Sekido Katsuhisa , Tachinami Hidetake , Ikeda Atsushi , Imaue Shuichi , Fujiwara Kumiko , Noguchi Makoto
Published: October 2019

Objective

Recent studies have demonstrated the pro‐tumour role of CD36 in multiple cancer types. However, its role has not been well elucidated in oral squamous cell carcinoma (OSCC). Here, we aimed to evaluate the role of CD36 in proliferation and migration of OSCC cells.

Methods

Human OSCC cell lines HSC‐2, HSC‐3, HSC‐4 and Ca9‐22 were assessed for proliferation by staining with the cell proliferation marker Ki‐67. We also assessed migration activity, and the expression of cell adhesion molecules such as E‐cadherin and β‐catenin and platelet‐derived growth factor receptors (PDGFRs) of CD36‐positive cells.

Results

CD36‐positive cells showed increased expression of Ki‐67 and migration activity compared with CD36‐negative cells. Moreover, CD36‐positive cells showed reduced expression of E‐cadherin and β‐catenin, whereas the expression of PDGFRs increased compared with that in CD36‐negative cells.

Conclusions

Our results strongly suggest that CD36 has an important role in facilitating the proliferation and migration activity of OSCC cells, indicating its usefulness in the diagnosis of high‐grade tumour and targeted therapy of oral cancer.
Atopic dermatitis made easy: The Schachner Ladder
Authors: Oberlin Kate E. , Nanda Sonali
Published: October 2019

The vast majority of atopic dermatitis follows a mild, chronic relapsing course. In this article, we highlight the art and practice of treating atopic dermatitis based upon a foundation of maintenance care and a ladder of therapy that can teach patients and their families how to best tailor their pharmaceutical options to optimize the management of their disease.
Inequality and Bias in the Demand for and Supply of News
Authors: Owen Ann L. , Wei Andrew
Published: October 2019

Objectives

We examine how the supply and demand for news stories that reference an individualistic concept change in response to changes in inequality and the prevailing ideology.

Methods

We use Google Trends data to construct an index of demand for individualistic news and a database of newspaper articles to construct an index of supply. We estimate fixed effects models on state and DMA‐level data from 1993 to 2017.

Results

Demand for individualistic news is higher in more conservative areas and it is even stronger when inequality rises. Supply of individualistic news is higher when the share of income to the top 1 percent is higher. The supply effect is strongest in more liberal areas.

Conclusion

These results provide evidence of both confirmation bias influencing demand and media capture influencing supply. Confirmation bias and media capture are distinct phenomenon, but provide reinforcing explanations for why consumption of individualistic news increases with inequality.
ToolBox: Live Imaging of intracellular organelle transport in induced pluripotent stem cell‐derived neurons
Authors: Boecker Clemens Alexander , Olenick Mara A. , Gallagher Elizabeth R. , Ward Michael E. , Holzbaur Erika L. F.
Published: October 2019

Induced pluripotent stem cells (iPSCs) hold promise to revolutionize studies of intracellular transport in live human neurons and to shed new light on the role of dysfunctional transport in neurodegenerative disorders. Here, we describe an approach for live imaging of axonal and dendritic transport in iPSC‐derived cortical neurons. We use transfection and transient expression of genetically‐encoded fluorescent markers to characterize the motility of Rab‐positive vesicles, including early, late and recycling endosomes, as well as autophagosomes and mitochondria in iPSC‐derived neurons. Comparing transport parameters of these organelles with data from primary rat hippocampal neurons, we uncover remarkable similarities. In addition, we generated lysosomal‐associated membrane protein 1 (LAMP1)‐enhanced green fluorescent protein (EGFP) knock‐in iPSCs and show that knock‐in neurons can be used to study the transport of endogenously labeled vesicles, as a parallel approach to the transient overexpression of fluorescently labeled organelle markers.
Thin-film metrology of tilted and curved surfaces by imaging Mueller-matrix ellipsometry
Authors: Duwe Matthias , Quast Jan-Henrik , Schneider Stefan , Fischer Daniel , Beck Uwe
Published: October 2019

For the vast majority of ellipsometric measurements, the application of planar substrates is mandatory and requires a proper sample alignment prior to the measurement. Here, the authors present a generalized approach of how to extract the isotropic ellipsometric sample parameters from an imaging Mueller-matrix measurement even if the sample is significantly misaligned. They validate the method by layer-thickness calculations based on imaging Mueller-matrix measurements of flat crystalline silicon samples that were misaligned on purpose. Furthermore, they also exploit this method’s capabilities to perform spatially resolved layer-thickness measurements of a single-layer indium-tin-oxide coating on a fused-silica microlens without the need of realignment or repositioning of the sample during the measurement.
Workplace Dynamics in Professional Sport: A Case Study of Identification, Political Skill, and Personal Control
Authors: Swanson Steve , Todd Samuel Y.
Published: October 2019

This case is based on a collection of real-life scenarios encountered by employees working for professional sport organizations. The workplace in this environment contains circumstances distinct to the sport context which this case aims to highlight. A small work group of three individuals with diverse backgrounds representing key departments in a professional basketball club are brought together to lead a difficult challenge in the community. Over the course of the season, several meetings and personal interactions play out which present difficulties in productivity due to individual differences in human relations capacity and varying psychological connections with the environment. In combination with the teaching notes, the case is designed to highlight (1) the special nature of employee identification in the professional sport setting, (2) an array of political skills which are relevant and useful to the sport workplace, and (3) the role of perceived personal control in sport organizations. An overview of theory and its specific application to the case is provided along with discussion questions and answers to aid instructors in effectively engaging with students around the topical areas.
Through the Hoop: Understanding the Person-Job-Organization-Environment Fit Theory to Attract Sport Managers to a New NBA Franchise
Authors: Ingerson Lynley , Naraine Michael L.
Published: October 2019

This case study explores the elements of fit between individuals, job opportunities, an NBA franchise, and its environment. Developing the right job descriptions for attracting a talented team of sport managers to Buffalo, who are capable of managing the highly competitive Buffalo Braves basketball franchise, is fundamental to getting the fit right. The focus of this case includes exploring motives and rewards for the various management roles devised, understanding the concept of ‘fit’ in hiring talented and innovative sport managers, developing clear responsibilities, and effectively aligning the expectations within a psychological contract between each new management role and organization at the Buffalo Braves.
The Isometric Horizontal Push Test: Test–Retest Reliability and Validation Study
Authors: Dello Iacono Antonio , Valentin Stephanie , Sanderson Mark , Halperin Israel
Published: October 2019

Purpose: To investigate the test–retest reliability and criterion validity of the isometric horizontal push test (IHPT), a newly designed test that selectively measures the horizontal component of maximal isometric force. Methods: Twenty-four active males with ≥3 years of resistance training experience performed 2 testing sessions of the IHPT, separated by 3 to 4 days of rest. In each session, subjects performed 3 maximal trials of the IHPT with 3 minutes of rest between them. The peak force outputs were collected simultaneously using a strain gauge and the criterion equipment consisting of a floor-embedded force plate. Results: The test–retest reliability of peak force values was nearly perfect (intraclass correlation coefficient = ∼.99). Bland–Altman analysis showed excellent agreement between days with nearly no bias for strain gauge 1.2 N (95% confidence interval [CI], −3 to 6 N) and force plate 0.8 N (95% CI, −4 to 6 N). A nearly perfect correlation was observed between the strain gauge and force plate (r = .98, P < .001), with a small bias of 8 N (95% CI, 1.2 to 15 N) in favor of the force plate. The sensitivity of the IHPT was also good, with smallest worthwhile change greater than standard error of measurement for both the strain gauge (smallest worthwhile change: 29 N; standard error of measurement: 17 N; 95% CI, 14 to 20 N) and the force plate (smallest worthwhile change: 29 N; standard error of measurement: 18 N; 95% CI, 14 to 19 N) devices. Conclusions: The high degree of validity, reliability, and sensitivity of the IHPT, coupled with its affordability, portability, ease of use, and time efficacy, point to the potential of the test for assessment and monitoring purposes.
Trichoderma reesei
Dehydrogenase, a Pyrroloquinoline Quinone-Dependent Member of Auxiliary Activity Family 12 of the Carbohydrate-Active Enzymes Database: Functional and Structural Characterization
Authors: Turbe-Doan Annick , Record Eric , Lombard Vincent , Kumar Rajender , Levasseur Anthony , Henrissat Bernard , Garron Marie-Line
Published: October 2019

Pyrroloquinoline quinone (PQQ) is an important cofactor synthesized by prokaryotes and involved in enzymatic alcohol and sugar oxidation. In eukaryotes, the benefit of PQQ as a vitamin has been suggested but never proved. Recently, the first eukaryotic enzyme using PQQ was characterized in the basidiomycete
Coprinopsis cinerea
, demonstrating that fungi are able to use PQQ as an enzyme cofactor. This discovery led to the classification of the fungal PQQ-dependent enzymes in auxiliary activity family 12 (AA12) of the Carbohydrate-Active Enzymes (CAZy) database (
www.cazy.org
) classification. In the present paper, we report on the characterization of the ascomycete AA12 enzyme from
Trichoderma reesei
(
Tr
AA12). Our enzymatic and phylogenetic results show divergence with the only other member of the family characterized, that from the basidiomycete
Coprinopsis cinerea
. The crystallographic structure of
Tr
AA12 shows similarities to the global active-site architecture of bacterial glucose dehydrogenases, suggesting a common evolution between the two families.
Quaternary glaciovolcanism in the Canadian Cascade volcanic arc—Paleoenvironmental implications
Authors: Wilson* A.M. , Russell J.K.
Published: October 2019

Volcanoes that interact with the cryosphere preserve indicators of their eruption environments. These glaciovolcanoes and their deposits have powerful potential as proxies of local and global paleoclimates. The Garibaldi volcanic belt is the northern (Canadian) segment of the Cascade volcanic arc. In this study, we compiled a comprehensive database of Quaternary volcanic landforms and deposits in the Garibaldi volcanic belt. We found that the region exhibits a high degree of volcanic diversity, and a significant component of this diversity is due to the abundance of glaciovolcanoes. These include: tuyas, tindars, subglacial tephra cones, ice-impounded lavas, subglacial domes and breccias, subglacial lava flows, and lava-dominated tuyas. As a group, they inform the presence, thickness, and transient properties of ancient, continental-scale ice sheets (i.e., the Cordilleran ice sheet) that have waxed and waned in thickness and extent across the region. We ascribe much of the character of glaciovolcanism in the Garibaldi volcanic belt to a wide range of magma compositions (alkaline basalt to rhyolite) and to the extreme relief of the landscape. We used forensic volcanologic evidence, in conjunction with our database, to define a terrestrial-based reconstruction of ice-sheet thickness and extent that spans the latter half of the Quaternary (i.e., past ~1 m.y.). We then compared our reconstruction to the marine isotope stage (MIS) record and found a number of positive correlations and discordances. We show glaciovolcanoes to be an excellent, and underutilized, proxy for Earth’s paleoclimate, and a powerful tool for reconstructing ice sheets predating the last glaciation.
New perspective on the nineteenth-century golden pumice deposit of Kīlauea Volcano
Authors: Biass Sébastien , Swanson Donald A. , Houghton Bruce F.
Published: October 2019

The golden pumice deposit (unit K1) represents one of the latest episodes of Hawaiian fountaining in the Keanakāko‘i Tephra and is the product of the first high fountaining eruption at Kīlauea summit in ~300 yr, since the caldera formed in ca. 1500 CE. We present a new physical characterization of the deposit based on over 200 field sites, all affected by severe erosion, alteration, and silicic encrusting. We detail the deposit geometry, stratigraphic and structural relationships, and componentry to constrain its volume and reconstruct the eruptive sequence. The deposit is then discussed and set against other young episodes of high fountaining at Kīlauea.

We interpret the golden pumice as the product of a days-long eruptive sequence with a source located inside a caldera much deeper than that of today. The eruption probably started along a NE-SW–oriented fissure and migrated toward a single vent in the southwestern part of the caldera, where at least two high Hawaiian-style fountains produced a tephra deposit of ~6 × 106 m3. Stratigraphic contacts reveal that erosion occurred not only between, but also during the fountaining episodes, suggesting heavy rainfall during deposition. Field observations during this study also led to the discovery of the first stratigraphic evidence that the eastern pumice postdates the golden pumice, which contributes to the new definition of the stratigraphy of the Keanakāko‘i Tephra presented in this volume.
Large hydromagmatic eruption related to Fernandina Volcano’s 1968 caldera collapse—Deposits, landforms, and ecosystem recovery
Authors: Howard* Keith A. , Simkin† Tom , Geist Dennis J. , Merlen Godfrey , Nolf§ Bruce
Published: October 2019

The hydromagmatic eruption that immediately preceded the 1968 caldera collapse of Fernandina Volcano, Galápagos, which had a volcano explosivity index (VEI) of 4, offers a case study of powerful eruptions where basaltic magma interacts with caldera-ponded water. The 4-d-long hydromagmatic eruption sequence records an early stage and a small fraction of the volume of magmatic withdrawal that led the caldera floor to lower 350 m over the next 10 d. Erupted tephra was lithic-rich. The small proportion of juvenile basaltic glass included blocky fragments, Pele’s tears, and Pele’s hair. Pyroclastic density currents swept across the western summit plateau 600–700 m above the vent and deposited dunes, cross-bedded and rubbly breccia deposits, imbricated lag blocks, and ash plasters, and toppled trees. Blocks ejected out of the caldera formed impact craters on the volcano’s flank >600 m higher and >1 km away. Ejected blocks are mostly basalt but include cumulate olivine gabbro. The vent area enlarged by 300 × 106 m3 during the eruption. A small adjacent fault-bounded block subsided after the eruption. Lake water and groundwater confined within the caldera by ring dikes were available to interact with hot rocks and magma. In our interpretation, this water helped to trigger and feed the eruption by interacting with rocks above a lowering magma column. Ecosystems recovered rapidly on the tephra. Eruptions have not diminished the island’s biodiversity despite Fernandina’s high rate of volcanic activity, including the massive resurfacing in 1968. Stratigraphic evidence suggests that the 1968 eruption may be only the latest in a series of explosive eruptions from the caldera.
U-Pb zircon geochronology of calc-alkaline ash-flow tuff units in the Mogollon-Datil volcanic field, southern New Mexico
Authors: Rentz Shannon P. , Michelfelder Gary S. , Coble Matthew A. , Salings* Emily
Published: October 2019

The Mogollon-Datil volcanic field is a 40–24 Ma cluster of calderas that formed during ignimbrite flare-up eruptions in southern New Mexico associated with sub-duction, and possible delamination, of the Farallon plate beneath the North American plate. This study uses magmatic zircon sampled from four ignimbrites from a nested caldera system and an additional ignimbrite located outside of the nested system to compare the processes and timing of magma accumulation in southern New Mexico. These ignimbrites include: the Whitewater Tuff, the Cooney Canyon Tuff, the Davis Canyon Tuff, and the Shelley Peak Tuff from the Mogollon Mountains and the Bell Top 4 Tuff from the Uvas volcanic field. The ignimbrites range from crystal-poor, high-silica rhyolite to crystal-rich, low-silica rhyolite. We compare previous 40Ar/39Ar sanidine eruption ages to new U-Pb crystallization ages and trace-element compositions of zircon. Weighted mean zircon ages define two magmatic groups. Group one includes the Bell Top Tuff (34.5 ± 0.5 Ma), the Cooney Canyon Tuff (34.8 ± 0.8 Ma), and the Whitewater Creek Tuff (36.2 ± 0.4 Ma). The second group includes the Davis Canyon Tuff (28.7 ± 0.5 Ma) and the Shelley Peak Tuff (29.6 ± 0.5 Ma). Weighted mean zircon ages are within published 40Ar/39Ar ages, with the exception of the Shelley Peak Tuff, which is ~1 m.y. older. Hafnium contents and Th/U and Yb/Gd ratios suggest the dominant mechanism that produced eruptible melt was rejuvenation or remobilization of a crystal mush accompanied by minimal partial melting of the continental crust.
Numerical basin modeling of the Laptev Sea Rift, NE Russia
Authors: Brandes Christian , Franke Dieter , Piepjohn Karsten , Gaedicke Christoph
Published: October 2019

The Laptev Sea Rift in the East Siberian continental margin plays an important role in the geodynamic models for the opening of the Eurasia Basin. The active Gakkel Ridge, which also represents the boundary between the North America and Eurasia plates, abruptly meets the continental margin of the Laptev Sea. On the continental shelf in the prolongation of the Gakkel Ridge, a rift developed since the Late Cretaceous/Early Cenozoic with the formation of five roughly north-south trending depocenters. To better understand the evolution of this rift, a basin modeling study was carried out with PetroMod® software. The modeled sections used in this study were developed on the basis of depth-converted reflection seismic sections. The sections cover the Anisin Basin in the north and the southeastern margin of the Ust´ Lena Rift in the south. The numerical simulations are supported by tectonic and sedimentological field data that were collected in outcrops during the CASE 13 expedition to the New Siberian Islands in 2011. For the Anisin Basin different scenarios were modeled with rift onsets between 110 Ma and 66 Ma. The results show that the present-day temperature field in the area of the Anisin Basin and at the southeastern margin of the Ust´ Lena Rift is characterized by horizontal, seafloor-parallel isotherms. Geohistory curves extracted from the 2D simulations indicate a twofold rift evolution with a stronger initial subsidence in the Late Cretaceous to Early Paleogene and a moderate subsidence in Late Paleogene and Neogene times. Based on the modeling results, an early rift onset around 110 Ma seems to be more realistic than a later one around 66 Ma.
Tonian and Silurian magmatism in Nordaustlandet: Svalbard’s place in the Caledonian orogen
Authors: McClelland* William C. , von Gosen* Werner , Piepjohn* Karsten
Published: October 2019

The Nordaustlandet terrane of Svalbard plays a critical role in evaluating strike-slip displacements in the Caledonian orogen. Comparison of Silurian and Tonian magmatism in Nordaustlandet, East Greenland, and the Pearya terrane on Ellesmere Island provides a means to evaluate models of large-scale versus minimal displacements. Augen gneiss with an emplacement age of 972 ± 5 Ma demonstrates that the Tonian granite suite is coeval with the calc-alkaline Kap Hansteen volcanic rocks. Zircon from Silurian leucosomes, leucogranites, and granites is dominated by xenocrystic components, making it analytically difficult to isolate magmatic versus inherited age domains. Zircon systematics from a relatively undeformed Silurian granite (431 ± 5 Ma) resemble those of similar granites interpreted to be Tonian in age (e.g., Kontaktberget granite). Assuming less deformed granites of Nordaustlandet are Silurian, synemplacement or syntectonic deformation of Tonian augen gneiss and volcanic rocks is no longer required. Tonian magmatic rocks of Svalbard share a common origin with basement rocks of the Pearya terrane within a continental arc system, but are distinctly older than Tonian igneous and metamorphic rocks of East Greenland. Migmatite complexes and granite intrusions in Nordaustlandet, with ages ranging from 440 to 425 Ma, are coeval with granites in East Greenland that record the combined effects of subduction beneath Laurentia and mid-crustal melting. Migmatites in East Greenland are juxtaposed with low grade rocks by syn-contraction normal faults whereas migmatites show gradational contacts into lower grade rocks on Nordaustlandet. These differences in basement age and structural setting preclude proximity of the Nordaustlandet terrane with East Greenland during the 440–400 Ma continent-continent collision phase (Scandian) of the Caledonian orogen. Similarly, differences in depositional, magmatic, and metamorphic history between the Pearya terrane basement and Nordaustlandet terrane argue against simple offset of crustal fragments. The Pearya and Nordaustlandet terranes likely were not involved in the main phase of crustal thickening directly related to collision of Baltica and Laurentia, but rather resided on a convergent boundary north of the Scandian continent-continent collision zone, consistent with models of Gee and Teben’kov (2004) and Johansson et al. (2005).
Defining tectonic boundaries using detrital zircon signatures of Precambrian metasediments from Svalbard’s Southwestern Caledonian Basement Province
Authors: Ziemniak Grzegorz , Kośmińska Karolina , Schneider David A. , Majka Jarosław , Lorenz Henning , McClelland William C. , Wala Virginia T. , Manecki Maciej
Published: October 2019

Detrital zircon provenance studies of Precambrian metasedimentary rocks in Wedel Jarlsberg Land and Sørkapp Land, Svalbard’s Southwestern Caledonian Basement Province, were conducted to evaluate local stratigraphic correlations and the role of long-distance strike-slip displacements in assembling the basement of the Arctic Caledonides. The detrital zircon U-Pb age spectra of the late Mesoproterozoic to Neoproterozoic metasediments revealed mainly Mesoproterozoic to Paleoproterozoic age signatures characteristic for a Grenville–Sveconorwegian orogen provenance. These results confirmed a stratigraphic correlation between basement units of southern Sørkapp Land and the Isbjørnhamna Group of Wedel Jarlsberg Land and suggest relocation of the tectonic boundary between the Eimfjellet Complex and the Isbjørnhamna Group above the Eimfjellbreane Formation. Moreover, the results support the Vimsodden Kosibapasset Shear Zone (VKZ) as a major tectonic boundary and highlight the inhomogeneity in the Southwestern Caledonian Basement Province. The detrital zircon age signatures south of the VKZ bear similarities with coeval metasediments of the Northwestern Caledonian Basement Province of Svalbard and other localities in the Greenland and Scandinavian Caledonides. In contrast, the detrital zircon age spectra north of the VKZ are comparable with the high Arctic Neoproterozoic sediments of Baltican affinity. In conjunction with previous studies, the results suggest that the basement units may continue across the traditional boundaries of the Svalbard’s Caledonian basement provinces.
Late Cretaceous–Paleogene burial and exhumation history of the Southwestern Basement Province, Svalbard, revealed by zircon (U-Th)/He thermochronology
Authors: Barnes* Christopher J. , Schneider David A.
Published: October 2019

We apply zircon (U-Th)/He low-temperature thermochronology to metasedimentary sequences of the Southwestern Basement Province of Svalbard to investigate the shallow crustal tectonics of Svalbard and the High Arctic. We resolve Cretaceous through Paleogene time-temperature histories for four areas of the province: Sørkapp Land, Wedel Jarlsberg Land, Oscar II Land, and Prins Karls Forland. Results indicate peak Late Cretaceous temperatures of ~175–185 °C in the south (Sørkapp Land, Wedel Jarlsberg Land) and >200 °C in the north (Oscar II Land) as a consequence of maximum burial and an elevated geothermal gradient (>40 °C/km). Late Cretaceous cooling affected all areas during regional exhumation related to initial rifting in the Eurasian Basin to the north. A subsequent heating event (recorded at Wedel Jarlsberg Land and Oscar II Land) from ca. 53–47 Ma is interpreted to result from tectonic burial during Eurekan deformation and development of the West Spitsbergen Fold-and-Thrust Belt. Our thermal models reveal a subsequent cooling event (47–34 Ma) corresponding to a shift in tectonic regime from compression to dextral strike-slip kinematics during Eurekan deformation; exhumation of the West Spitsbergen Fold-and-Thrust Belt coincided with strike-slip tectonism. Throughout Eurekan deformation, Prins Karls Forland resided at temperatures >200 °C and records cooling during post-34 Ma extension. Our models indicate 2.5–3.5 km of unroofing in Wedel Jarlsberg Land and Oscar II Land, and >4 km of unroofing of Prins Karls Forland, which is a deeper structural level of the West Spitsbergen Fold-and-Thrust Belt than other exposures on Spitsbergen. The results of this study document elevated heat flow in the Late Cretaceous, extend spatial resolution of Late Cretaceous crustal cooling documented across Svalbard, and illustrate the temporal and thermal evolution of the West Spitsbergen Fold-and-Thrust Belt, which is necessary for an improved understanding of Arctic geodynamics.
Coal rank data and tectonic structure of Mesozoic and Paleogene sediments in North Greenland
Authors: Paech Hans-Jürgen , Estrada Solveig
Published: October 2019

Vitrinite reflectance (Rr) data, combined with structural field evidence, allow insights into the thermal and tectonic history of North Greenland. During the tectonism at the Cretaceous–Paleocene boundary, the thermal imprint varies considerably, mostly controlled by active fault zones. The Upper Cretaceous sequences along the Harder Fjord Fault Zone show Rr values between ~3.2% (Frigg Fjord area) and ~2.1% (Depotbugt area). Along the Trolle Land Fault Zone, Rr varies between 1.3% and 2.9% in the Herlufsholm Strand area, and between 1.6% and 2.2% in the Kilen area. These maturity variations along regional fault zones are connected with varying deformation intensity and explained by unequal conductive heat flow. In the Kap Washington Group, the high coal rank attaining 5.4% Rr is associated with ductile deformation, and is additionally influenced by magmatic activity, i.e., convective heat flow. The coalification is low in regions a greater distance away from active faults, e.g., in Lower Cretaceous sediments of Herluf Trolle Land with ~0.5% Rr. The Paleogene Thyra Ø Formation was deposited following deformation and thermal imprint at the Cretaceous–Paleogene boundary. It remained undeformed and shows a reduced Rr of ~0.55%, reflecting burial thermal imprint. A later thermal event (known from the literature) that affected Mesozoic sediments, and possibly also locally Paleogene sediments close to the continental margin, is assumed to be related to heat flow from the active plate boundary between northeast Greenland and Svalbard.

Based on detailed geochemical and mineralogical studies, thin, yellowish jarosite-bearing, clayey horizons within the Thyra Ø Formation are interpreted to probably originate from volcanic ashes erupted during the first stage of the opening of the North Atlantic.