bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective Cleavage of C−O Bonds in Lignin Catalyzed by Rhenium(VII) Oxide (Re2O7)
Authors: Qi Zaojuan , Zhang Bo , Ji Jianwei , Li Xinxin , Dai Tao , Guo Haiwei , Wang Aiqin , Lu Lican , Li Changzhi 
Published: February 2018

AbstractThe selective cleavage of C−O bonds in typical model lignin β‐O‐4 compounds and deconstruction of a realistic lignin feedstock catalyzed by Re2O7 is described. High yields of C−O cleavage products (up to 97.8 %) from model compounds and oils (76.3 %) from organosolv pinewood lignin were obtained under mild conditions. Evidence for the pathway of this catalytic process is also provided.
Effects of Alkali‐Metal Ions and Counter Ions in Sn‐Beta‐Catalyzed Carbohydrate Conversion
Authors: Elliot Samuel G. , Tolborg Søren , Madsen Robert , Taarning Esben , Meier Sebastian 
Published: February 2018

AbstractAlkali‐metal ions have recently been shown to strongly influence the catalytic behavior of stannosilicates in the conversion of carbohydrates. An effect of having alkali‐metal ions present is a pronounced increase in selectivity towards methyl lactate. Mechanistic details of this effect have remained obscure and are herein addressed experimentally through kinetic experiments and isotope tracking. The presence of alkali‐metal ions has a differential effect in competing reaction pathways and promotes the rate of carbon–carbon bond breakage of carbohydrate substrates, but decreases the rates of competing dehydration pathways. Further addition of alkali‐metal ions inhibits the activity of Sn‐Beta in all major reaction pathways. The alkali‐metal effects on product distribution and on the rate of product formation are similar, thus pointing to a kinetic reaction control and to irreversible reaction steps in the main pathways. Additionally, an effect of the accompanying basic anions is shown, supposedly facilitating the cation exchange and eliciting a different concentration‐dependent effect to that of neutral alkali‐metal salts.
Species turnover and invasion of dominant freshwater invertebrates alter biodiversity–ecosystem‐function relationship
Authors: Little Chelsea J. , Altermatt Florian 
Published: February 2018

AbstractFreshwater ecosystems rely on allochthonous resources. Integration of these subsidies depends on diversity of both terrestrial resources and aquatic shredder and decomposer communities, but the diversity effects on leaf litter breakdown and decomposition are less clear in aquatic than terrestrial ecosystems. We need a better understanding of this relationship because aquatic communities are rapidly changing with species invasions and anthropogenic impacts. Here, we experimentally disentangled the effects of leaf and shredder richness on leaf litter breakdown by macroinvertebrates in mesocosm experiments using three species of amphipods, a dominant guild of crustaceans in European freshwater ecosystems. Increased leaf richness led to lower‐than‐predicted leaf consumption by native shredders, with mixed evidence of resource‐switching or prioritization of preferred food items within a leaf mix. Higher shredder species richness never promoted leaf consumption rates compared to predictions from relevant single‐species experiments, and instead sometimes substantially decreased leaf consumption. We then conducted a meta‐analysis of leaf litter consumption rates by seven widely distributed amphipod species (the three used in the experiments and four additional species). As expected based on our own experiments, nonnative amphipod species generally had lower biomass‐adjusted leaf litter consumption rates, although their larger body size led to higher per‐individual leaf consumption rates. Contamination of the water by metals, pesticides, and other chemicals additionally significantly decreased leaf litter consumption by multiple native and nonnative species compared to unpolluted systems. While the meta‐analysis suggested that litter consumption, and thus breakdown, would decline if native shredders are replaced by nonnative heterospecifics, complete species replacement is not the only outcome following immigration in a meta‐community context. Our experiments suggest that breakdown rates could remain reasonably high where native species coexist with nonnative arrivals. Experiments that neglect the ecological realism of species coexistence will necessarily mischaracterize effects on ecosystem functioning.
Evaluation of invasive and non‐invasive methods to monitor rodent abundance in the Arctic
Authors: Fauteux Dominique , Gauthier Gilles , Mazerolle Marc J. , Coallier Nicolas , Bêty Joël , Berteaux Dominique 
Published: February 2018

AbstractMonitoring rodent abundance is critical to understand direct and indirect trophic interactions in most northern terrestrial ecosystems. However, logistic constraints can prevent researchers from using capture–mark–recapture methods, a robust approach to estimate abundance. Our objective was to determine the correlation between abundance estimates of Arctic lemmings obtained from live‐trapping data with spatially explicit capture–recapture models (SECR; N/ha) and abundance indices obtained from snap‐trapping along trap lines (N/100 trap‐nights), winter nest sampling along transects with distance sampling models (N/ha), burrow counting within quadrats (N/100 m2), and incidental observations (N/100 observer‐hr). We also evaluated the impact of reduced sampling effort on the bias and precision of each abundance estimate. Data from brown (Lemmus trimucronatus) and collared lemmings (Dicrostonyx groenlandicus) were collected each year from 2007 to 2016 on Bylot Island, Nunavut, Canada. Snap‐trapping (r = 0.90) and incidental observations (r = 0.92) yielded the highest correlations with live‐trapping densities for brown lemmings, the most abundant species. When combining abundance of both lemming species, snap‐trapping (r = 0.77) and incidental observations (r = 0.90) also yielded the highest correlations. Indices from winter nests and burrows were also correlated (r > 0.50) with live‐trapping densities, but to a lesser degree. We found that bias generally increased when effort was reduced for methods involving modeling of capture or detection probabilities (i.e., live‐trapping, winter nests), but remained low for the other methods. In contrast, precision of estimates remained high when usingSECRmodels, but decreased substantially for the other methods during years of low lemming abundance. Non‐convergence ofSECRand distance sampling models generally increased when reducing effort and was frequent in years of low lemming abundance. Interestingly, collecting >200 h of incidental observations generated highly reliable estimates of lemming abundance compared to results from live‐trapping, indicating that such non‐invasive method can provide valuable data at low cost. We provide guidelines on other invasive or non‐invasive methods that can be used when small mammals cannot be live‐trapped and suggest the effort required to achieve a given precision.
Is doping of cognitive performance an anti‐herbivore adaptation? Alkaloids inhibiting acetylcholinesterase as a case
Authors: Ejsmond Maciej J. , Provenza Frederick D. 
Published: February 2018

AbstractHistorically, people who study interactions between plants and herbivores focused on the ecological costs and benefits of synthesizing secondary metabolites. These compounds have diverse functions including defenses against herbivores. Some plants produce alkaloids that act as acetylcholinesterase inhibitors, increasing both the level and duration of action of the neurotransmitter acetylcholine with potential toxic effects in insects and mammals. Yet, among a number of neuroactive plant chemicals, alkaloids that inhibit acetylcholinesterase (AIA) display nootropic activities, that is, positively affect cognition, learning, and memory in mammals. This creates a paradox: Neuroactive AIA, expected to punish herbivores, enhance cognition, learning, and memory. A prevailing view is AIA are pesticides that adversely affecting the nervous systems of herbivorous insects, and the positive influences in mammals are merely a by‐product of other functions. We review literature on the behavioral ecology of diet choice, food‐aversion learning, and neurophysiological actions of AIA in mammals to provide a more comprehensive view of the adaptive significance of AIA. These compounds act as anti‐herbivory defenses that influence flavor (taste plus odor) preference/aversion, the formation of memories, and the feeding behavior of mammalian herbivores. Thus, what appears from an insect standpoint to be an enigma makes sense for mammals: AIA enable mammalian herbivores to quickly learn and remember specific plant(s) and the locations where they ate those plant(s). We provide examples of AIA, synthesized by over 200 plant species in 16 families, which affect learning and memory in mammals. Using 36 examples of acetylcholinesterase inhibitors synthesized by plants in 58 families, we also show that acetylcholinesterase blockers contribute to anti‐herbivore chemical defense by affecting food‐aversion learning and memory in mammalian herbivores. We provide an evolutionary rationale for why natural selection may favor synthesis of chemicals that positively affect mental functions of herbivores. Our hypothesis, which challenges the current view that plant chemical defenses are aimed solely at destabilizing herbivore physiology, facilitates a broader understanding of diet preferences and feeding behavior in mammalian herbivores.
Persistence of depressive symptoms and gait speed recovery in older adults after hip fracture
Authors: Rathbun Alan M. , Shardell Michelle D. , Stuart Elizabeth A. , Gruber‐Baldini Ann L. , Orwig Denise , Ostir Glenn V. , Hicks Gregory E. , Hochberg Marc C. , Magaziner Jay 
Published: February 2018

ObjectiveDepression after hip fracture in older adults is associated with worse physical performance; however, depressive symptoms are dynamic, fluctuating during the recovery period. The study aim was to determine how the persistence of depressive symptoms over time cumulatively affects the recovery of physical performance.MethodsMarginal structural models estimated the cumulative effect of persistence of depressive symptoms on gait speed during hip fracture recovery among older adults (n = 284) enrolled in the Baltimore Hip Studies 7th cohort. Depressive symptoms at baseline and at 2‐month and 6‐month postadmission for hip fracture were evaluated by using the Center for Epidemiological Studies Depression Scale, and persistence of symptoms was assessed as a time‐averaged severity lagged to standardized 3 m gait speed at 2, 6, and 12 months.ResultsA 1‐unit increase in time‐averaged Center for Epidemiological Studies Depression score was associated with a mean difference in gait speed of −0.0076 standard deviations (95% confidence interval [CI]: −0.0184, 0.0032; P = .166). The association was largest in magnitude from baseline to 6 months: −0.0144 standard deviations (95% CI: −0.0303, 0.0015; P = 0.076). Associations for the other time intervals were smaller: −0.0028 standard deviations (95% CI: −0.0138, 0.0083; P = .621) at 2 months and −0.0121 standard deviations (95% CI: −0.0324, 0.0082; P = .238) at 12 months.ConclusionAlthough not statistically significant, the magnitude of the numerical estimates suggests that expressing more depressive symptoms during the first 6 months after hip fracture has a meaningful impact on functional recovery.
Evaluation of bone marrow stem cell response to PLA scaffolds manufactured by 3D printing and coated with polydopamine and type I collagen
Authors: Teixeira Bruna Nunes , Aprile Paola , Mendonça Roberta H. , Kelly Daniel J. , Thiré Rossana Mara da Silva Moreira 
Published: February 2018

AbstractThe majority of synthetic polymers used in 3 D printing are not designed to promote specific cellular interactions and hence possess limited bioactivity. Most of the strategies proposed to overcome this limitation demand multiple and expensive processing steps. This study aimed to evaluate the surface modification of 3D‐printed poly(lactic acid) (PLA) scaffolds with polydopamine (PDA) coating as an alternative strategy to enhance their bioactivity and to facilitate the immobilization of type I collagen (COL I) onto the implant surface. Physical and chemical properties of PLA scaffolds coated with PDA, COL I or both were evaluated. The response of porcine bone marrow stem cells (MSCs) to the coatings was also investigated. The PDA layer improved COL immobilization onto the surface of the PLA scaffolds by 92%. The combination of PDA and COL functionalizations provided the best conditions for early‐stage (<7 days) cell response. In addition, the PDA plus COL surface facilitated the robust deposition of extracellular matrix in the first 14 days of cell culture. Although the behavior of the MSCs appeared to be similar for both uncoated PLA and PDA plus COL‐coated scaffolds by day 21, cells seeded onto PDA plus COL scaffolds produced substantially higher amounts of alkaline phosphatase. These results indicate that the osteoinductivity of 3D‐printed PLA scaffolds can be enhanced by PDA and type I collagen coatings. This surface modification of polymeric scaffolds represents a promising strategy for bone tissue engineering. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 37–49, 2019.
Evaluating the durability of UHMWPE biomaterials used for articulating surfaces of joint arthroplasty using delamination tests
Authors: Sakoda Hideyuki , Osaka Yuta , Uetsuki Keita , Okamoto Yoshihiro , Haishima Yuji 
Published: February 2018

AbstractUltra‐high molecular weight polyethylene (UHMWPE) is the most popular material used for the articulating surface of joint replacements. Delamination is a common fatigue‐related failure mode in UHMWPE components; however, the relationship between delamination resistance and fatigue crack growth has not been reported. Here, the delamination resistance of contemporary UHMWPE materials, including highly cross‐linked UHMWPE (HXLPE), vitamin E blended UHMWPE (VEPE), and vitamin E blended HXLPE (VEXLPE), was measured to verify a previously proposed accelerated test method using a U‐shaped sliding motion; the results were compared with those of fatigue crack growth tests. The oxidative stability of each material was estimated using Fourier transform infrared analysis. UHMWPE sterilized by gamma irradiation in an inert atmosphere and annealed HXLPE had lower delamination resistance than virgin UHMWPE after artificial aging. This was consistent with previous findings from retrieval studies, and in vitro knee simulator and ball‐on‐flat unidirectional reciprocation wear studies. In contrast, remelted HXLPE, VEPE, and VEXLPE showed excellent delamination resistance after artificial aging. The results of the delamination tests were not consistent with those of fatigue crack growth tests, indicating the complex delamination mechanism and importance of evaluating these factors separately. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 107B: 65–72, 2019.
Higher Dairy Food Intake Is Associated With Higher Spine Quantitative Computed Tomography (QCT) Bone Measures in the Framingham Study for Men But Not Women
Authors: van Dongen Laura H , Kiel Douglas P , Soedamah-Muthu Sabita S , Bouxsein Mary L , Hannan Marian T , Sahni Shivani 
Published: February 2018

ABSTRACT

Previous studies found that dairy foods were associated with higher areal bone mineral density (BMD). However, data on bone geometry or compartment-specific bone density is lacking. In this cross-sectional study, the association of milk, yogurt, cheese, cream, milk+yogurt, and milk+yogurt+cheese intakes with quantitative computed tomography (QCT) measures of bone were examined, and we determined if associations were modified by serum vitamin D (25-OH D, tertiles) or age (&lt;50 versus ≥50 years). Participants were 1522 men and 1104 women (aged 32 to 81 years, mean 50 years [men]; 55 years [women]) from the Framingham Heart Study with measures of dairy food intake (servings/wk) from a food-frequency questionnaire, volumetric BMD (vBMD, integral and trabecular, g/cm3), cross-sectional area (CSA, cm2), and estimated vertebral compressive strength (VCS, N) and 25-OH D (radioimmunoassay). Sex-specific multivariable linear regression was used to calculate the association of dairy food intake (energy adjusted) with each QCT measure, adjusting for covariates. Mean milk intake ±SD was 6 ± 7 servings/week in both men and women. In men, higher intake of milk, milk+yogurt, and milk+yogurt+cheese was associated with higher integral (p = 0.001 to 0.006) and trabecular vBMD (p = 0.006 to 0.057) and VCS (p = 0.001 to 0.010). Further, a higher cheese intake was related with higher CSA (p = 0.049). In women, no significant results were observed for the dairy foods, except for a positive association of cream intake with CSA (p = 0.016). The associations appeared to be stronger in older men. Across 25-OH D tertiles, dairy was positively associated with bone health. In summary, men with higher intakes of milk, milk+yogurt, and milk+yogurt+cheese had higher trabecular and integral vBMD and VCS but not CSA. Dairy intake seems to be most beneficial for older men, and dairy continued to have positive associations among all 25-OH D levels. © 2018 American Society for Bone and Mineral Research.
Direct conversion of cellulose to sorbitol via an enhanced pretreatment with ionic liquids
Authors: Gao Kai , Xin Jiayu , Yan Dongxia , Dong Huixian , Zhou Qing , Lu Xingmei , Zhang Suojiang 
Published: February 2018

ABSTRACTBACKGROUNDDirect conversion of cellulose into platform chemicals, is regarded as one of the most promising aspects of biomass resource utilization. However, the development of direct conversion of cellulose to high value‐added chemicals such as sorbitol still remains a tremendous problem owing to the robust structure of cellulose to resist degradation.RESULTSIn this study, ball‐milled microcrystalline cellulose was dissolved in ionic liquids, and finally converted to sorbitol smoothly through hydrolytic hydrogenation processes. Both ball‐milling and ionic liquids dissolution can effectively destroy the strong inter‐ and intramolecular hydrogen bond network formed between hydroxyl groups within cellulose. Furthermore, water‐soluble ionic cellulose came into being due to the dissolution of cellulose in ionic liquids, which increased the contact of cellulose to catalyst remarkably. The crystalline index of cellulose can be reduced from 79.9% to 3.2% under an optimum ball‐milling time of 4 h, and the preferred cellulose dissolution solvent was selected to be [Amim]Cl. Finally, the final product, sorbitol was successfully synthesized over the catalysis of Nafion NR50 and Ru/AC (active carbon) with the sorbitol yield to be 34.3% at 150 °C for 1 h.CONCLUSIONThis study proposed a novel approach about direct conversion of cellulose to sorbitol with ionic liquids as well as extended the application of ionic liquids in the field of conversion of renewable biomass to platform chemicals. © 2018 Society of Chemical Industry
How much can synthetic cannabinoid damage the heart? A case of cardiogenic shock following resistant ventricular fibrillation after synthetic cannabinoid use
Authors: Yamanoglu Adnan , Celebi Yamanoglu Nalan Gokce , Evran Tugba , Sogut Ozgur 
Published: February 2018

AbstractNew substances are constantly being added to the content of synthetic cannabinoids (SCs). SCs can affect the cardiovascular system and cause hypotension and bradycardia, myocardial infarction, atrial fibrillation, prolonged QTc, and Mobitz type II atrioventricular block. However, no cases associated with ventricular fibrillation (VF) have been reported to date. We report a case of a 26‐year‐old male patient admitted to the emergency department due to altered consciousness after SC use and requiring prolonged cardiopulmonary resuscitation due to resistant VF and cardiogenic shock.
Elevated and super‐elevated CO2 differ in their interactive effects with nitrogen availability on fruit yield and quality of cucumber
Authors: Dong Jinlong , Xu Qiao , Gruda Nazim , Chu Wenying , Li Xun , Duan Zengqiang 
Published: February 2018

AbstractBACKGROUNDElevated carbon dioxide (CO2) and nitrogen (N) availability can interactively promote cucumber yield, but how the yield increase is realized remains unclear, whilst the interactive effects on fruit quality are unknown. In this study, cucumber plants (Cucumis sativus L. cv. Jinmei No. 3) were grown in a paddy soil under three CO2 concentrations – 400 (ambient CO2), 800 (elevated CO2, eCO2) and 1200 µmol mol−1 (super‐elevated CO2) – and two N applications – 0.06 (low N) and 0.24 g N kg−1 soil (high N).RESULTSCompared with ambient CO2, eCO2 increased yield by 106% in high N but the increase in total biomass was only 33%. This can result from greater carbon translocation to fruits from other organs, indicated by the increased biomass allocation from stems and leaves, particularly source leaves, to fruits and the decreased concentrations of fructose and glucose in source leaves. Super‐elevated CO2 reduced the carbon allocation to fruits thus yield increase (71%). Additionally, eCO2 also increased the concentrations of fructose and glucose in fruits, maintained the concentrations of dietary fiber, phosphorus, potassium, calcium, magnesium, sulfur, manganese, copper, molybdenum and sodium, whilst it decreased the concentrations of nitrate, protein, iron, and zinc in high N. Compared with eCO2, super‐elevated CO2 can still improve the fruit quality to some extent in low N availability.CONCLUSIONSElevated CO2 promotes cucumber yield largely by carbon allocation from source leaves to fruits in high N availability. Besides a dilution effect, carbon allocation to fruits, carbohydrate transformation, and nutrient uptake and assimilation can affect the fruit quality. © 2018 Society of Chemical Industry
Prevalence of Persistent Median Arteries in the Pediatric Population on Ultrasonography
Authors: Carry Patrick M. , Nguyen Amy K. , Merritt Glenn R. , Ciarallo Christopher , Chatterjee Debnath , Park Jung , Miller Nancy H. , Scott Frank A. 
Published: February 2018

ObjectivesTo use real‐time ultrasonography to estimate the prevalence of persistent median arteries in a cohort of pediatric orthopedic patients.MethodsWith Institutional Review Board approval, patients between the ages of 3 months and 19 years were recruited for this cross‐sectional study. Variables of interest included demographics, underlying diagnoses, and the presence of a Doppler‐confirmed median artery. Ultrasonographic examinations were performed on both upper extremities by a single investigator. Patient‐ and limb‐level analyses were performed. A multivariable generalized logistic regression analysis was used to test the association between the prevalence of limb‐specific persistent median arteries and age. A generalized estimating equation was used to adjust for the inclusion of multiple limbs from the same patient.ResultsA total of 135 patients (270 limbs) were evaluated. The patient‐specific prevalence rate (persistent median arteries present in 1 or both limbs) was 26.7%. Among these patients (n = 36), a persistent median artery was present bilaterally in 55.6% (n = 20). The limb‐specific prevalence rate (proportion of limbs with a persistent median artery) was 20.7%. After adjusting for race, for every 1‐year increase in age, the odds of a persistent median artery decreased by 4.4%. After adjusting for age, African Americans were significantly more likely to present with a persistent median artery (odds ratio, 3.78; 95% confidence interval, 1.25–11.48).ConclusionsUltrasonography can effectively visualize anatomic variants, such as persistent median arteries, in the pediatric population. The prevalence of persistent median arteries was higher than anticipated, especially among African American patients.