bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of freshwater mussels on the vertical distribution of anaerobic ammonia oxidizers and other nitrogen-transforming microorganisms in upper Mississippi river sediment
Authors: Black Ellen M. , Chimenti Michael S. , Just Craig L. 
Published: July 2017

Targeted qPCR and non-targeted amplicon sequencing of 16S rRNA genes within sediment layers identified the anaerobic ammonium oxidation (anammox) niche and characterized microbial community changes attributable to freshwater mussels. Anammox bacteria were normally distributed (Shapiro-Wilk normality test, W-statistic =0.954, p = 0.773) between 1 and 15 cm depth and were increased by a factor of 2.2 (p < 0.001) at 3 cm below the water-sediment interface when mussels were present. Amplicon sequencing of sediment at depths relevant to mussel burrowing (3 and 5 cm) showed that mussel presence reduced observed species richness (p = 0.005), Chao1 diversity (p = 0.005), and Shannon diversity (p < 0.001), with more pronounced decreases at 5 cm depth. A non-metric, multidimensional scaling model showed that intersample microbial species diversity varied as a function of mussel presence, indicating that sediment below mussels harbored distinct microbial communities. Mussel presence corresponded with a 4-fold decrease in a majority of operational taxonomic units (OTUs) classified in the phyla Gemmatimonadetes, Actinobacteria, Acidobacteria, Plantomycetes, Chloroflexi, Firmicutes, Crenarcheota, and Verrucomicrobia. 38 OTUs in the phylum Nitrospirae were differentially abundant (p < 0.001) with mussels, resulting in an overall increase from 25% to 35%. Nitrogen (N)-cycle OTUs significantly impacted by mussels belonged to anammmox genus Candidatus Brocadia, ammonium oxidizing bacteria family Nitrosomonadaceae, ammonium oxidizing archaea genus Candidatus Nitrososphaera, nitrite oxidizing bacteria in genus Nitrospira, and nitrate- and nitrite-dependent anaerobic methane oxidizing organisms in the archaeal family “ANME-2d” and bacterial phylum “NC10”, respectively. Nitrosomonadaceae (0.9-fold (p < 0.001)) increased with mussels, while NC10 (2.1-fold (p < 0.001)), ANME-2d (1.8-fold (p < 0.001)), and Candidatus Nitrososphaera (1.5-fold (p < 0.001)) decreased with mussels. Co-occurrence of 2-fold increases in Candidatus Brocadia and Nitrospira in shallow sediments suggests that mussels may enhance microbial niches at the interface of oxic–anoxic conditions, presumably through biodeposition and burrowing. Furthermore, it is likely that the niches of Candidatus Nitrososphaera and nitrite- and nitrate-dependent anaerobic methane oxidizers were suppressed by mussel biodeposition and sediment aeration, as these phylotypes require low ammonium concentrations and anoxic conditions, respectively. As far as we know, this is the first study to characterize freshwater mussel impacts on microbial diversity and the vertical distribution of N-cycle microorganisms in upper Mississippi river sediment. These findings advance our understanding of ecosystem services provided by mussels and their impact on aquatic biogeochemical N-cycling.
Concentric traveling ionospheric disturbances triggered by the launch of a SpaceX Falcon 9 rocket
Authors: Lin Charles C. H. , Shen Ming‐Hsueh , Chou Min‐Yang , Chen Chia‐Hung , Yue Jia , Chen Po‐Cheng , Matsumura Mitsuru 
Published: July 2017

AbstractWe report the first observation of concentric traveling ionospheric disturbances (CTIDs) triggered by the launch of a SpaceX Falcon 9 rocket on 17 January 2016. The rocket‐triggered ionospheric disturbances show shock acoustic wave signature in the time rate change (time derivative) of total electron content (TEC), followed by CTIDs in the 8–15 min band‐pass filtering of TEC. The CTIDs propagated northward with phase velocity of 241–617 m/s and reached distances more than 1000 km away from the source on the rocket trajectory. The wave characteristics of CTIDs with periods of 10.5–12.7 min and wavelength ~ 200–400 km agree well with the gravity wave dispersion relation. The optimal wave source searching and gravity wave ray tracing technique suggested that the CTIDs have multiple sources which are originated from ~38–120 km altitude before and after the ignition of the second‐stage rocket, ~200 s after the rocket was launched.
Permafrost collapse shifts alpine tundra to a carbon source but reduces N2O and CH4 release on the northern Qinghai‐Tibetan Plateau
Authors: Mu C. C. , Abbott B. W. , Zhao Q. , Su H. , Wang S. F. , Wu Q. B. , Zhang T. J. , Wu X. D. 
Published: July 2017

AbstractImportant unknowns remain about how abrupt permafrost collapse (thermokarst) affects carbon balance and greenhouse gas flux, limiting our ability to predict the magnitude and timing of the permafrost carbon feedback. We measured monthly, growing‐season fluxes of CO2, CH4, and N2O at a large thermokarst feature in alpine tundra on the northern Qinghai‐Tibetan Plateau (QTP). Thermokarst formation disrupted plant growth and soil hydrology, shifting the ecosystem from a growing‐season carbon sink to a weak source but decreasing feature level CH4 and N2O flux. Temperature‐corrected ecosystem respiration from decomposing permafrost soil was 2.7 to 9.5‐fold higher than in similar features from Arctic and Boreal regions, suggesting that warmer and dryer conditions on the northern QTP could accelerate carbon decomposition following permafrost collapse. N2O flux was similar to the highest values reported for Arctic ecosystems and was 60% higher from exposed mineral soil on the feature floor, confirming Arctic observations of coupled nitrification and denitrification in collapsed soils. Q10 values for respiration were typically over 4, suggesting high‐temperature sensitivity of thawed carbon. Taken together, these results suggest that QTP permafrost carbon in alpine tundra is highly vulnerable to mineralization following thaw, and that N2O production could be an important noncarbon permafrost climate feedback. Permafrost collapse altered soil hydrology, shifting the ecosystem from a carbon sink to carbon source but decreasing CH4 and N2O flux. Little to no vegetation recovery after stabilization suggests potentially large net carbon losses. High N2O flux compared to Arctic and Boreal systems suggests noncarbon permafrost climate feedback.
Tropical Pacific climate variability over the last 6000 years as recorded in Bainbridge Crater Lake, Galápagos
Authors: Thompson Diane M. , Conroy Jessica L. , Collins Aaron , Hlohowskyj Stephan R. , Overpeck Jonathan T. , Riedinger‐Whitmore Melanie , Cole Julia E. , Bush Mark B. , Whitney H. , Corley Timothy L. , Kannan Miriam Steinitz 
Published: July 2017

AbstractFinely laminated sediments within Bainbridge Crater Lake, Galápagos, provide a record of El Niño–Southern Oscillation (ENSO) events over the Holocene. Despite the importance of this sediment record, hypotheses for how climate variability is preserved in the lake sediments have not been tested. Here we present results of long‐term monitoring of the local climate and limnology and a revised interpretation of the sediment record. Brown‐green, organic‐rich, siliciclastic laminae reflect warm, wet conditions typical of El Niño events, whereas carbonate and gypsum precipitate during cool, dry La Niña events and persistent dry periods, respectively. Applying this new interpretation, we find that ENSO events of both phases were generally less frequent during the mid‐Holocene (~6100–4000 calendar years B.P.) relative to the last ~1500 calendar years. Abundant carbonate laminations between 3500 and 3000 calendar years B.P. imply that conditions in the Galápagos region were cool and dry during this period when the tropical Pacific E‐W sea surface temperature (SST) gradient likely strengthened. The frequency of El Niño and La Niña events then intensified dramatically around 1750–2000 calendar years B.P., consistent with a weaker SST gradient and an increased frequency of ENSO events in other regional records. This strong interannual variability persisted until ~700 calendar years B.P., when ENSO‐related variability at the lake decreased as the SST gradient strengthened. Persistent, dry conditions then dominated between 300 and 50 calendar years B.P. (A.D. 1650–1900, ± ~100 years), whereas wetter conditions and frequent El Niño events dominated in the most recent century.
Plant Cell Walls
Authors: Srivastava Vaibhav , McKee Lauren S , Bulone Vincent 
Published: July 2017

Abstract

Common to all plant species, the cell wall is the tough outer coat that protects the plant cell. The cell wall is mostly carbohydrate‐based, comprising three major classes of polysaccharides: cellulose, hemicellulose and pectin. There are also important structural proteins as well as phenolic and aliphatic polymers. The cell wall provides mechanical strength to the plant body, allowing upright growth and structure formation, and also plays important roles in cellular processes such as cell expansion, tissue differentiation, intercellular communication, water movement and defence responses against pests or pathogens. Cell walls may even be involved in signal sensing during pattern formation in plant development.

Key Concepts

The cell wall is the outermost layer of the plant cell.

The cell wall consists essentially of three major types of carbohydrates – cellulose, hemicellulose and pectins – and proteins.

Some specialised cell wall types, for example woody cell walls also contain phenolic and aliphatic polymers in addition to carbohydrate polymers.

The cell wall is a dynamic structure whose composition changes during cell, tissue and plant development and in response to various stresses.

The cell wall provides mechanical strength to the plant body.

The cell wall plays important roles in processes such as cell expansion, tissue differentiation, intercellular communication, water movement and defence responses against pests or pathogens.
Plant Cell Walls: Improved Resources for Biofuels and Value‐Added Products through Genetic Engineering
Authors: Hao Zhangying , Loqué Dominique 
Published: July 2017

Abstract

To mitigate fossil‐fuel shortages and the environmental impact of excess fossil‐fuel consumption, bioconversion of biomass into biofuels has emerged as a clean and sustainable alternative. During the past decade, a significant amount of progress has been made in understanding and improving the production of second‐generation biofuels from lignocellulosic biomass. While some challenges still need to be overcome, some of advancements led to the development of improved feedstocks to boot sugar release and incorporate functional groups into lignins to support the production of high‐value‐added by‐products.

Key Concepts

Plants sequester CO
2
and sunlight energy in their cell walls.

The largest resource of sugars is stored in plant cell walls.

Plant cell walls can be biologically converted into biofuels.

Processes of plant cell walls into biofuels and value‐added products need optimisation.

Every cell‐wall components need to be valorised: ‘No waste policy’.

Plants can be engineered to optimise cell‐wall conversion efficiency.
Role of Nonmotor Microtubule‐Associated Proteins in Mitotic Spindle Assembly
Authors: Drpic Danica , Maiato Helder 
Published: July 2017

Abstract

The assembly of a microtubule (MT)‐based bipolar spindle is a distinct hallmark of mitosis. Mitotic spindle assembly is tightly controlled in order to ensure proper chromosome attachment and segregation during mitosis. This regulation is achieved by the coordinated action of many motor and nonmotor MT‐associated proteins (MAPs). Owing to the distinctive capacity of MAPs to associate with the MT minus and/or plus ends, as well as with the MT lattice, they play an essential role in the spatial and temporal regulation of MT behaviour during mitotic spindle assembly.

Key Concepts

The mitotic spindle is a dynamic structure composed of microtubules, motor and nonmotor proteins.

Proper chromosome alignment and segregation during mitosis requires bipolar spindle assembly.

Nonmotor microtubule‐associated proteins are involved in spindle pole focusing, microtubule dynamics, kinetochore‐microtubule attachment stability and cytokinesis.

Nonmotor microtubule‐associated proteins associate with microtubule plus and minus ends (+TIPs and −TIPs, respectively) as well as with the microtubule lattice.

Nonmotor microtubule‐associated proteins are tightly regulated during the cell cycle.
Selective Association Between Tetris Game Play and Visuospatial Working Memory: A Preliminary Investigation
Authors: Lau‐Zhu Alex , Holmes Emily A. , Butterfield Sally , Holmes Joni 
Published: July 2017

SummaryRecent experimental and clinical research has suggested that Tetris game play can disrupt maladaptive forms of mental imagery because Tetris competes for limited cognitive resources within visuospatial working memory (WM) that contribute to imagery. Whether or not Tetris performance is selectively associated with visuospatial WM remains to be tested. In this study, young adults (N = 46) completed six standardized measures indexing verbal and non‐verbal reasoning, verbal and visuospatial short‐term memory, and verbal and visuospatial WM. They also played Tetris. Consistent with the hypothesis that visuospatial WM resources support Tetris game play, there was a significant moderate positive relationship between Tetris scores and visuospatial WM performance but no association with other cognitive ability measures. Findings suggest that Tetris game play involves both storage and processing resources within visuospatial WM. These preliminary results can inform interventions involving computer games to disrupt the development of maladaptive visual imagery, for example, intrusive memories of trauma. © 2017 The Authors. Applied Cognitive Psychology Published by John Wiley & Sons Ltd.
Mechanical recycling simulation of polylactide using a chain extender
Authors: Cosate de Andrade Marina Fernandes , Fonseca Gustavo , Morales Ana Rita , Mei Lucia Helena Innocentini 
Published: July 2017

AbstractThis work studied the commercial chain extender effectiveness on the mechanical recycling simulation of a pristine PLA using a single‐screw extruder. We processed the material by two extrusion cycles to simulate a recycling process. In the second extrusion, part of the material was processed with chain extender and we evaluated its molecular weight, thermal degradation, melt flow index (MFI), thermal transitions, and mechanical properties. The molecular weight for the extruded neat PLA decreased and the MFI and crystallinity degree increased while the mechanical properties worsened. The onset thermal degradation occurred at lower temperature for the processed material. With the introduction of the chain extender, there was a recovery of properties with the increase in the polymer molecular weight, decrease in the MFI and crystallinity degree, and an improvement in both thermal stability and mechanical properties in relation to recycled PLA without this component.
POEMSsyndrome: 2017 Update on diagnosis, risk stratification, and management
Authors: Dispenzieri Angela 
Published: July 2017

AbstractDisease OverviewPOEMS syndrome is a paraneoplastic syndrome due to an underlying plasma cell neoplasm. The major criteria for the syndrome are polyradiculoneuropathy, clonal plasma cell disorder (PCD), sclerotic bone lesions, elevated vascular endothelial growth factor, and the presence of Castleman disease. Minor features include organomegaly, endocrinopathy, characteristic skin changes, papilledema, extravascular volume overload, and thrombocytosis. Diagnoses are often delayed because the syndrome is rare and can be mistaken for other neurologic disorders, most commonly chronic inflammatory demyelinating polyradiculoneuropathy. POEMS syndrome should be distinguished from the Castleman disease variant of POEMS syndrome, which has no clonal PCD and typically little to no peripheral neuropathy but has several of the minor diagnostic criteria for POEMS syndrome.DiagnosisThe diagnosis of POEMS syndrome is made with 3 of the major criteria, two of which must include polyradiculoneuropathy and clonal plasma cell disorder, and at least one of the minor criteria.Risk StratificationBecause the pathogenesis of the syndrome is not well understood, risk stratification is limited to clinical phenotype rather than specific molecular markers. The number of clinical criteria is not prognostic, but the extent of the plasma cell disorder is. Those patients with an iliac crest bone marrow biopsy that does not reveal a plasma cell clone are candidates for local radiation therapy; those with a more extensive or disseminated clone will be candidates for systemic therapyRisk‐Adapted TherapyFor those patients with a dominant sclerotic plasmacytoma, first‐line therapy is irradiation. Patients with diffuse sclerotic lesions or disseminated bone marrow involvement and for those who have progression of their disease 3–6 months after completing radiation therapy should receive systemic therapy. Corticosteroids are temporizing, but alkylators are the mainstay of treatment, either in the form of low‐dose conventional therapy or high dose with stem cell transplantation. Lenalidomide shows promise with manageable toxicity. Thalidomide and bortezomib also have activity, but their benefit needs to be weighed against their risk of exacerbating the peripheral neuropathy. The benefit of anti‐VEGF antibodies is conflicting. Prompt recognition and institution of both supportive care measures and therapy directed against the plasma cell result in the best outcomes.
Agreement between specific measures of adiposity and associations with high blood pressure in black South African women
Authors: Kruger Herculina S. , Botha‐Ravyse Chrisna , Havemann‐Nel Lize , Doubell Maretha , van Rooyen Johannes M. 
Published: July 2017

AbstractObjectivesTo derive percentage body fat (%BF) cut‐points according to body mass index (BMI) categories for adult black South African women and to investigate the agreement between adiposity classifications according to WHO BMI and %BF cut‐points. The secondary aim was to determine the association between these different adiposity measures and high blood pressure.MethodsBlack women aged 29–65 years (n = 435) from Ikageng, South Africa, were included in this cross‐sectional study. Socio‐demographic and anthropometric data were collected (weight, height and BMI). %BF using dual‐energy X‐ray absorptiometry and blood pressure were measured.ResultsThere was significant agreement between three %BF categories: low/normal (<35.8% age 29–49 years; or <38% age 50–65 years), overweight range (35.8–40.7% age 29–49 years; or 38–42.1% age 50–65 years) and obese (≥40.7% age 29–49 years; or ≥42.1% age 50–65 years) and three BMI categories: low/normal (<25 kg/m2), overweight range (25–29.9 kg/m2) and obese (≥30kg/m2); (κ = 0.62, P < .0001). Despite statistically significant agreement between groups, more than half of overweight individuals were misclassified as having either a normal (30.2%) or obese %BF (25.5%). %BF misclassification was low in the low/normal and obese BMI ranges. After adjustment for confounders, obesity (BMI ≥ 30kg/m2), as well as high %BF were significantly associated with high blood pressure (OR = 1.75, 95% CI 1.09–2.81 versus OR = 1.92, 95% CI 1.15–3.23, respectively).ConclusionDespite significant agreement between BMI and %BF categories, considerable misclassification occurred in the overweight range. Participants with excessive %BF had a greater odds of high blood pressure than those in the highest BMI category.
Indolizine–Squaraines: NIR Fluorescent Materials with Molecularly Engineered Stokes Shifts
Authors: McNamara Louis E. , Rill Tana A. , Huckaba Aron J. , Ganeshraj Vigneshraja , Gayton Jacqueline , Nelson Rachael A. , Sharpe Emily Anne , Dass Amala , Hammer Nathan I. , Delcamp Jared H. 
Published: July 2017

AbstractThe development of deep red and near infrared emissive materials with high quantum yields is an important challenge. Several classes of squaraine dyes have demonstrated high quantum yields, but require significantly red‐shifted absorptions to access the NIR window. Additionally, squaraine dyes have typically shown narrow Stokes shifts, which limits their use in living biological imaging applications due to dye emission interference with the light source. Through the incorporation of indolizine heterocycles we have synthesized novel indolizine squaraine dyes with increased Stokes shifts (up to >0.119 eV, >50 nm increase) and absorptions substantially further into the NIR region than an indoline squaraine benchmark (726 nm versus 659 nm absorption maxima). These materials have shown significantly enhanced water solubility, which is unique for squaraine dyes without water‐solubilizing substituents. Absorption, electrochemical, computational, and fluorescence studies were undertaken and exceptional fluorescence quantum yields of up 12 % were observed with emission curves extending beyond 850 nm.
To Avoid Chasing Incorrect Chemical Structures of Chiral Compounds: Raman Optical Activity and Vibrational Circular Dichroism Spectroscopies
Authors: Polavarapu Prasad L. , Covington Cody L. , Raghavan Vijay 
Published: July 2017

AbstractA chemical structure (CS) identifies the connectivities between atoms, and the nature of those connections, for a given elemental composition. For chiral molecules, in addition to the identification of CS, the identification of the correct absolute configuration (AC) is also needed. Several chiral natural products are known whose CSs were initially misidentified and later corrected, and these errors were often discovered during the total synthesis of natural products. In this work, we present a new and convenient approach that can be used with Raman optical activity (ROA) and vibrational circular dichroism (VCD) spectroscopies, to distinguish between the correct and incorrect CSs of chiral compounds. This approach involves analyzing the spectral similarity overlap between experimental spectra and those predicted with advanced quantum chemical theories. Significant labor needed for establishing the correct CSs via chemical syntheses of chiral natural products can thus be avoided.
Facing herbivory on the climb up: Lost opportunities as the main cost of herbivory in the wild yam Dioscorea praehensilis
Authors: Di Giusto Bruno , Dounias Edmond , McKey Doyle B. 
Published: July 2017

AbstractPlants with simple architecture and strong constraints on their growth may offer critical insights into how growth strategies affect the tolerance of plants to herbivory. Although Dioscorea praehensilis, a wild yam of African forests, is perennial, both aerial apparatus and tuber are annually renewed. Each year, the tuber produces a single stem that climbs from the ground to the forest canopy. This stem bears no leaves and no branches until it reaches optimal light conditions. Once in the canopy, the plant's production fuels the filling of a new tuber before the plant dies back to the ground. We hypothesized that if deprived of ant defense, the leafless growth phase is a vulnerable part of the cycle, during which a small amount of herbivory entails a high cost in terms of loss of opportunity. We compared the growth of stems bearing ants or not as well as of intact stems and stems subjected to simulated or natural herbivory. Ants reduce herbivory; herbivory delays arrival to the canopy and shortens the season of production. Artificially prolonging the stem growth to the canopy increased plant mortality in the following year and, in surviving plants, reduced the stem diameter and likely the underground reserves produced. Tuber size is a key variable in plant performance as it affects both the size of the aerial apparatus and the duration of its single season of production. Aerial apparatus and tuber are thus locked into a cycle of reciprocal annual renewal. Costs due to loss of opportunity may play a major role in plant tolerance to herbivory, especially when architectural constraints interact with ecological conditions to shape the plant's growth strategy.