bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective binding of potassium and calcium ions to novel cyclic proanthocyanidins in wine by high‐performance liquid chromatography/high‐resolution mass spectrometry
Authors: Longo Edoardo , Rossetti Fabrizio , Merkyte Vakare , Obiedzińska Agnieszka , Boselli Emanuele
Published: July 2018

Rationale

Cyclic B‐type (referred also as crown) proanthocyanidins (PACs) were recently identified in wines. A high‐performance liquid chromatography/high‐resolution tandem mass spectrometry (HPLC/HRMS/MS) method was applied to study the binding of cyclic and non‐cyclic PACs to potassium and calcium ions, which affect the chemico‐physical stability of wines. Different binding affinities suggest that cyclic and non‐cyclic analogues, despite the equal number of monomer units, influence the colloidal stability of wine and are related to the grape variety or winemaking conditions.

Methods

Nineteen red and white wines were analysed by HPLC/HRMS/MS with positive electrospray ionization to investigate the distribution of novel cyclic PACs and their calcium, potassium and sodium adducts. Principal components analysis was used to study the distribution of the wines and the relationships among PACs with and without cation complexes.

Results

A dependence on specific isomers (and conformations) was found for the non‐cyclic procyanidin (PC) trimer whereas the cyclic tetrameric PACs were shown to bind better to potassium than their non‐cyclic analogues. The binding to these metals appeared to be influenced not only by the number of monomer units, but also by the conformation assumed by the molecules. Statistical analysis evidenced that the distribution of adducts in different wines is less influenced by the grape variety used for winemaking than their associated [M + H]+ species studied earlier.

Conclusions

Wines from 19 grape varieties were investigated in order to identify potassium and calcium complexes of non‐ and cyclic B‐type PACs that were recently discovered. The results showed a dependence of the distribution of metal complexes according to the cyclic or non‐cyclic geometry of PACs. The multivariate analysis of the mass spectrometric results showed a relationship with the grape variety; however, this was not as straightforward as evidenced for the non‐complexed species.
Simultaneous determination of tobacco minor alkaloids and tobacco‐specific nitrosamines in mainstream smoke by dispersive solid‐phase extraction coupled with ultra‐performance liquid chromatography/tandem orbitrap mass spectrometry
Authors: Zhang Xiaotao , Wang Ruoning , Zhang Li , Ruan Yibin , Wang Weiwei , Ji Houwei , Lin Fucheng , Liu Jian
Published: July 2018

Rationale

The minor alkaloids in tobacco play an important role in the chemical composition of cigarette smoke, and they are precursors of tobacco‐specific nitrosamines (4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK), N‐nitrosonornicotine (NNN), N‐nitrosoanabasine (NAB) and N‐nitrosoanatabine (NAT)). NNN and NNK are classified as group 1 carcinogens. A method quantitating both tobacco minor alkaloids and tobacco‐specific nitrosamines in mainstream smoke has not been reported.

Methods

Tobacco minor alkaloids and tobacco‐specific nitrosamines in cigarette mainstream smoke were extracted by sonication. The extract was cleaned up by dispersive solid‐phase extraction, and separation was achieved via ultra‐performance liquid chromatography/tandem orbitrap mass spectrometry.

Results

The method was validated by analysis of six replicate samples spiked with three levels of the analyses. The mean recoveries for the six replicates were from 84.7% to 118% with less than 15% relative standard deviation except myosmine at the low spiked level and the calculated detection limits were 0.066 to 13.2 ng/cig, respectively. The mean concentrations of nicotyrine, anabasine, nornicotine, anatabine, myosmine, 2,3‐bipyridine, cotinine, nicotelline, N‐formylnornicotine, NNK, NNN, NAB and NAT in 30 different brands of commercial cigarette smoke under the ISO smoking regimen were 2.50 μg/cig, 2.34 μg/cig, 3.21 μg/cig, 5.78 μg/cig, 2.83 μg/cig, 1.05 μg/cig, 1.55 μg/cig, 0.55 μg/cig, 2.48 μg/cig, 6.06 ng/cig, 3.62 ng/cig, 0.40 ng/cig and 6.15 ng/cig, respectively.

Conclusions

The proposed method was suitable for analysis of tobacco minor alkaloids and tobacco‐specific nitrosamines in cigarette mainstream smoke.
Silica Nanostructures, a Heterogeneous Surface for Dendrimer Functionalization
Authors: Heidarizadeh Mohammad , Doustkhah Esmail , Saberi Farveh , Rostamnia Sadegh , Hassankhani Asadollah , Rezaei Parisa Fathi , Ide Yusuke
Published: July 2018

Nowadays, giant organic molecules have taken a great attention in nanoarchitecturing of silica materials. Silica nanostructure binded dendrimers play a crucial role in the next‐generation technologies within many fields such as medicine, drug delivery, sensors, catalysis, water treatment, etc. This paper discusses silica nanostructures which are arrayed by dendrimers and have been used for many applications such as drug delivery and catalysis. Also, this paper elaborates some possible pathways of binding a dendrimer to a silica surface. Synthesis of dendrimers on the surface of silica nanostructure is also discussed.
Structural Insights and Third Order NLO Studies of Pseudohalide‐ Based Polymeric and Monomeric Congeners of Halo‐Substituted Parent Schiff Bases
Authors: Aiswarya Natarajan , Ajina Cheruvalath , Tom Lincy , Kurup Maliyeckal R. Prathapachandra
Published: July 2018

The present work focuses on the pseudohalide embodied copper(II) complexes of a tridentate Schiff base (HL) derived from N,N‐dimethylethylenediamine and 3,5‐dichloro‐2‐hydroxyacetophenone. Of them, two are coordination polymers and rest are monomers. The azide in the complex [Cu(L)(N3)]n, adopts an end‐on coordination mode begetting a trans helical propagation while the end‐to‐end bonding fashion of the dicyanamide in [Cu(L)[N(CN)2]n, fostered a meso‐helical chain. The interplay of covalent & non‐covalent forces develop the complexes into supramolecular architectures. Similar forces stitch the monomeric cyanato and thiocyanato complexes to chains. Quantification of intermolecular forces was achieved by surface analysis along with fingerprint plots. Charge‐transfer bands exhibit negative solvatochromic effect while the influence of the solvents on the geometry of the complexes is based on d‐d bands. Further, fluorescence and thermal studies were also done. The third order non‐linear optical (NLO) response of the complexes were recorded. Open aperture scan showed a positive NLO absorption coefficient and closed scan, a negative non‐linear refractive effect. A predominant refractive effect of the complexes make them ideal for optical switching applications.
Synthesis and Characterization of Potential Impurities of Dolutegravir: A HIV Drug
Authors: Gudisela Mura Reddy , Bommu Praveen , Navuluri Srinivasu , Mulakayala Naveen
Published: July 2018

Six major impurities were observed during the development of dolutegravir. All these impurities were identified by using HPLC and LC–MS analysis and were synthesized starting from (4R,12aS)‐7‐methoxy‐4‐methyl‐6,8‐dioxo‐3,4,6,8,12,12a‐hexahydro‐2H‐pyrido[1′, 2′:4,5] pyrazino [2, 1‐b][1, 3]oxazine‐9‐carboxylic acid 1. All the synthesized impurities were characterized by using 1H NMR, 13C NMR, Mass and HPLC analysis. These compounds can be used as a reference standard for the active pharmaceutical ingredient manufactures and research organizations.
Biamphiphilic Ionic Liquids‐Drug Mixtures: Interactional and Morphological Aspects
Authors: Vashishat Rajni , Sanan Reshu , Ray Debes , Aswal Vinod Kumar , Mahajan Rakesh Kumar
Published: July 2018

The interactional and morphology behavior of mixed system embracing chlorpromazine hydrochloride (CPZ) drug and surface active biamphiphilic ionic liquids (BAILs); 1‐hexyl‐3‐methylimidazolium dodecylsulfate ([C6mim][C12OSO3]) and 1‐butyl‐3‐methylimidazolium octylsulfate ([C4mim][C8OSO3]) at pH 7 have been investigated to develop new strategies to use BAILs as carriers of pharmaceutical active compounds. UV‐vis absorption spectroscopy and cyclic voltammetry (CV) methods are used to shed light on the foremost interactions governing CPZ + BAILs mixtures. The higher value of binding constant (Ka) and Gibbs free energy change (ΔG) for CPZ + [C6mim][C12OSO3] mixture, determined from absorbance measurements depict the existence of more attractive interactions than CPZ + [C4mim][C8OSO3]. The composition mediated self‐assembly of CPZ + BAIL mixed aggregates in bulk has been investigated by small angle neutron scattering (SANS), dynamic light scattering (DLS) and zeta potential measurements.
Enamine‐Mediated Azide‐Ketone [3 + 2] Cycloaddition of Azidoperfluoroalkanes
Authors: Blastik Zsófia E. , Klepetářová Blanka , Beier Petr
Published: July 2018

An effective synthesis of highly functionalized N‐perfluoroalkyl‐1,2,3‐triazoles from azidoperfluoroalkanes has been achieved. In situ generated enamines readily participate in the azide‐carbonyl [3+2] cycloaddition, providing a facile way to fully substituted triazole frameworks in good to excellent yields. The synthetic value of these triazoles was shown in the synthesis of perfluorinated 1,5‐disubstituted triazoles by hydrolysis and decarboxylation.
Directly Electrodeposited Cobalt Sulfide Nanosheets as Advanced Catalyst for Oxygen Evolution Reaction
Authors: Nan Kaikai , Du Hongfang , Su Lan , Li Chang Ming
Published: July 2018

CoS, a low cost and efficient electrocatalyst for oxygen evolution reaction (OER), has attract great research interest but its electrosynthesis to delicately tune the nanostructures has not been carried out. Herein, for the first time by the use of potassium thiocyanate (KSCN) as sulfur source, CoS nanosheets are time‐controlled electrosynthesized and further evolved to a 3D flower‐like nanostructure, in which KSCN plays a critical role. With a deposition time of 1200s, the catalyst shows excellent catalytic activity toward OER, achieving a small Tafel slope of 55 mV dec−1 and only requires an overpotential of 310 mV to deliver a current density of 10 mA cm−2, better than the benchmark IrO2 and other electrodeposited cobalt sulfide catalysts. The enhancement mechanism is attributed to the unique nanostructure offering a large electroactive surface while allowing reactants accessing the reaction surface and the produced oxygen bubble escaping out for a fast electrode kinetics toward OER.
Facile, Room Temperature, Electroless Deposited (Fe1−x,Mnx)OOH Nanosheets as Advanced Catalysts: The Role of Mn Incorporation
Authors: Suryawanshi Mahesh P. , Ghorpade Uma V. , Shin Seung Wook , Suryawanshi Umesh P. , Shim Hong Jae , Kang Soon Hyung , Kim Jin Hyeok
Published: July 2018

Herein, bimetallic iron (Fe)–manganese (Mn) oxyhydroxide ((Fe1−x,Mnx)OOH, FeMnOOH) nanosheets on fluorine‐doped tin oxide conducting substrates and on semiconductor photoanodes are synthesized by a facile, room temperature, electroless deposition method as catalysts for both electrochemical and photo‐electrochemical (PEC) water splitting, respectively. Surprisingly, Mn‐doped FeOOH can significantly modulate the nanosheet morphology to increase the active surface area, boost more active sites, and augment the intrinsic activity by tuning the electronic structure of FeOOH. Due to the 2D nanosheet architecture, the optimized FeMnOOH exhibits superior electrochemical activity and outstanding durability for the oxygen evolution reaction with a low overpotential of 246 mV at 10 mA cm−2 and 414 mV at 100 mA cm−2, and long‐term stability for 40 h without decay, which is comparable to the best electrocatalysts for water oxidation reported in the literature. By integrating with semiconductor photoanodes (such as α‐Fe2O3 nanorod (NR) arrays), bimetallic FeMnOOH catalysts achieve solar‐driven water splitting with a significantly enhanced PEC performance (3.36 mA cm−2 at 1.23 V vs reversible hydrogen electrode (RHE)) with outstanding long‐term stability (≈8 h) compared to that of the bare Fe2O3 NR (0.92 mA cm−2 at 1.23 V vs RHE).
Hepatoprotective effect of ginsenoside Rg1 from Panax ginseng on carbon tetrachloride‐induced acute liver injury by activating Nrf2 signaling pathway in mice
Authors: Ning Chenqing , Gao Xiaoguang , Wang Changyuan , Huo Xiaokui , Liu Zhihao , Sun Huijun , Yang Xiaobo , Sun Pengyuan , Ma Xiaodong , Meng Qiang , Liu Kexin
Published: July 2018

Oxidative stress and inflammatory response are well known to be involved in the pathogenesis of acute liver injury. This study was performed to examine the hepatoprotective effect of ginsenoside Rg1 (Rg1) against CCl4‐induced acute liver injury, and further to elucidate the involvement of Nrf2 signaling pathway in vivo and in vitro. Mice were orally administered Rg1 (15, 30, and 60 mg/kg) or sulforaphane (SFN) once daily for 1 week prior to 750 μL/kg CCl4 injection. The results showed that Rg1 markedly altered relative liver weights, promoted liver repair, increased the serum level of TP and decreased the serum levels of ALT, AST and ALP. Hepatic oxidative stress was inhibited by Rg1, as evidenced by the decrease in MDA, and increases in GSH, SOD, and CAT in the liver. Further research demonstrated that Rg1 suppressed liver inflammation response through repressing the expression levels of inflammation‐related genes including TNF‐α, IL‐1β, IL‐6, COX‐2, and iNOS. In addition, Rg1 enhanced antioxidative stress and liver detoxification abilities by up‐regulating Nrf2 and its target‐genes such as GCLC, GCLM, HO‐1, NQO1, Besp, Mrp2, Mrp3, Mrp4, and down‐regulating Cyp2e1. However, the changes in Nrf2 target‐genes, as well as ameliorative liver histology induced by Rg1 were abrogated by Nrf2 antagonist all‐transretinoic acid in vivo and Nrf2 siRNA in vitro. Overall, the findings indicated that Rg1 might be an effective approach for the prevention against acute liver injury by activating Nrf2 signaling pathway.
On fast quenches and spinning correlators
Authors: Goykhman Mikhail , Shachar Tom , Smolkin Michael
Published: July 2018

Abstract

We study global quantum quenches in a continuous field theoretic system with UV fixed point. Assuming that the characteristic inverse time scale of the smooth quench is much larger than all scales inherent to the system except for the UV-cutoff, we derive the universal scaling behavior of the two-point correlation functions associated with Dirac fields and spin-1 currents. We argue that in certain regimes our results can be recovered using the technique of operator product expansion.
Consent recommendations for research and international data sharing involving persons with dementia
Authors: Thorogood Adrian , Mäki‐Petäjä‐Leinonen Anna , Brodaty Henry , Dalpé Gratien , Gastmans Chris , Gauthier Serge , Gove Dianne , Harding Rosie , Knoppers Bartha Maria , Rossor Martin , Bobrow Martin ,   Global Alliance for Genomics and Health, Ageing and Dementia Task Team
Published: July 2018

Consent is generally required for research and sharing rich individual‐level data but presents additional ethical and legal challenges where participants have diminished decision‐making capacity. We formed a multi‐disciplinary team to develop best practices for consent in data‐intensive dementia research. We recommend that consent processes for research and data sharing support decision‐making by persons with dementia, protect them from exploitation, and promote the common good. Broad consent designed to endure beyond a loss of capacity and combined with ongoing oversight can best achieve these goals. Persons with dementia should be supported to make decisions and enabled to express their will and preferences about participation in advance of a loss of capacity. Regulatory frameworks should clarify who can act as a representative for research decisions. By promoting harmonization of consent practices across institutions, sectors, and countries, we hope to facilitate data sharing to accelerate progress in dementia research, care, and prevention.
“Hell was let loose on the country”: The Social History of Military Technology in the Republic of Biafra
Authors: Daly Samuel Fury Childs
Published: July 2018

The problem of armed crime in late twentieth-century Nigeria was closely connected to the events of the Nigerian Civil War (1967–1970). Legal records from the secessionist Republic of Biafra reveal how violent crime emerged as part of the military confrontation between Biafra and Nigeria. The wide availability of firearms, the Biafran state’s diminishing ability to enforce the law, and the gradual collapse of Biafra’s economy under the pressure of a Nigerian blockade made Biafran soldiers and civilians reliant on their weapons to obtain food and fuel, make claims to property, and settle disputes with one another. Criminal legal records illustrate how military technologies shape interactions and relationships in the places where they are deployed, and how those dynamics can endure after the war comes to an end. This speaks to larger theoretical questions about the symbolic and functional meanings of guns during and after wartime.
Cost-effectiveness of three different strategies for the treatment of first recurrent Clostridium difficile infection diagnosed in a community setting
Authors: Lam Simon W. , Neuner Elizabeth A. , Fraser Thomas G. , Delgado David , Chalfin Donald B.
Published: July 2018

Objective

A significant portion of patients with Clostridium difficile infections (CDI) experience recurrence, and there is little consensus on its treatment. With the availability of newer agents for CDI and the added burdens of recurrent disease, a cost-effectiveness analysis may provide insight on the most efficient use of resources.

Design

A decision-tree analysis was created to compare the cost-effectiveness of 3 possible treatments for patients with first CDI recurrence: oral vancomycin, fidaxomicin, or bezlotoxumab plus vancomycin. The model was performed from a payer’s perspective with direct cost inputs and a timeline of 1 year. A systematic review of literature was performed to identify clinical, utility, and cost data. Quality-adjusted life years (QALY) and incremental cost-effectiveness ratios were calculated. The willingness-to-pay (WTP) threshold was set at $100,000 per QALY gained. The robustness of the model was tested using one-way sensitivity analyses and probabilistic sensitivity analysis.

Results

Vancomycin had the lowest cost ($15,692) and was associated with a QALY gain of 0.8019 years. Bezlotoxumab plus vancomycin was a dominated strategy. Fidaxomicin led to a higher QALY compared to vancomycin, at an incremental cost of $500,975 per QALY gained. Based on our WTP threshold, vancomycin alone was the most cost-effective regimen for treating the first recurrence of CDI. Sensitivity analyses demonstrated the model’s robustness.

Conclusions

Vancomycin alone appears to be the most cost-effective regimen for the treatment of first recurrence of CDI. Fidaxomicin alone led to the highest QALY gained, but at a cost beyond what is considered cost-effective.
Glacier anomaly over the western Kunlun Mountains, Northwestern Tibetan Plateau, since the 1970s
Authors: WANG YETANG , HOU SHUGUI , HUAI BAOJUAN , AN WENLING , PANG HONGXI , LIU YAPING
Published: July 2018

Western Kunlun Mountain (WKM) glaciers show balanced or even slightly positive mass budgets in the early 21st century, and this is anomalous in a global context of glacier reduction. However, it is unknown whether the stability prevails at longer time scales because mass budgets have been unavailable before 2000. Here topographical maps, Shuttle Radar Topography Mission and Landsat data are used to examine the area and surface elevation changes of glaciers on the WKM since the 1970s. Heterogeneous glacier behaviors are observed not only in the changes of length and area, but also in the spatial distribution of surface elevation changes. However, on average, glacier area and elevation changes are not significant. Glaciers reduce in the area by 0.07 ± 0.1% a−1 from the 1970s to 2016. Averaged glacier mass loss is −0.06 ± 0.13 m w.e. a−1 from the 1970s to 1999. These findings show that the WKM glacier anomaly extends back at least to the 1970s.
A REACTION–DIFFUSION–ADVECTION EQUATION WITH COMBUSTION NONLINEARITY ON THE HALF-LINE
Authors: LI FANG , LI QI , LIU YUFEI
Published: July 2018

We study the dynamics of a reaction–diffusion–advection equation $u_{t}=u_{xx}-au_{x}+f(u)$ on the right half-line with Robin boundary condition $u_{x}=au$ at $x=0$, where $f(u)$ is a combustion nonlinearity. We show that, when $0<a<c$ (where $c$ is the travelling wave speed of $u_{t}=u_{xx}+f(u)$), $u$ converges in the $L_{loc}^{\infty }([0,\infty ))$ topology either to $0$ or to a positive steady state; when $a\geq c$, a solution $u$ starting from a small initial datum tends to $0$ in the $L^{\infty }([0,\infty ))$ topology, but this is not true for a solution starting from a large initial datum; when $a>c$, such a solution converges to $0$ in $L_{loc}^{\infty }([0,\infty ))$ but not in $L^{\infty }([0,\infty ))$ topology.
Screening of cell surface properties of potential probiotic lactobacilli isolated from human milk
Authors: Rokana Namita , Singh Brij Pal , Thakur Nishchal , Sharma Chetan , Gulhane Rohini Devidas , Panwar Harsh
Published: July 2018

Evaluation of eleven candidate probioticLactobacillusstrains isolated from human milk showed that some of the strains were well endowed with desirable cell surface and attachment attributes. The cell surface properties (hydrophobicity, auto-aggregation, attachment to collagen and HT-29 monolayer) of probioticLactobacillusspecies of human milk origin were compared with reference probiotic/ non-probiotic species and pathogenic strains. The bacterial adhesion to hydrocarbons (BATH) was determined using three aliphatic (Chloroform, n-Hexane and n-Octane) and two aromatic (Toluene and Xylene) solvents. Maximum affinity ofLactobacillusstrains towards chloroform and toluene indicated the presence of low electron acceptor/ acidic surface components on cell surface of most of the strains. The highest value of per cent hydrophobicity was recorded with chloroform in HM1 (L. casei) (97·10 ± 3·35%) and LGG (98·92 ± 1·24%). A moderate auto-aggregation attribute was observed in all of ourLactobacillusisolates. Only HM10, HM12 and HM13 exhibited comparatively enhanced precipitation rate after 7 h of incubation period. The adhesion potential to collagen matrix was highest in LGG (26·94 ± 5·83%), followed by HM1 (11·07 ± 3·54%) and HM9 (10·85 ± 1·74%) whereas, on HT-29 cells, HM8 (14·99 ± 3·61%), HM3 (13·73 ± 1·14%) and HM1 (11·21 ± 3·18%) could adhere effectively. In this manner, we noticed that although the cell surface properties and adhesion prospective of probiotic bacteria were strain dependent, five of our isolatesviz. HM1, HM3, HM8, HM9 and HM10 exhibited promising cell surface properties, which could be further targeted as indigenous probiotic.
Modelling multi-state health transitions in China: a generalised linear model with time trends
Authors: Hanewald Katja , Li Han , Shao Adam W.
Published: July 2018

Rapid population ageing in China has urged the need to understand health transitions of older Chinese to assist the development of social security programmes and financial products aimed at funding long-term care. In this paper, we develop a new flexible approach to modelling health transitions in a multi-state Markov model that allows for age effects, time trends and age-time interactions. The model is implemented in the generalised linear modelling framework. We apply the model to evaluate health transitions of Chinese elderly using individual-level panel data from the Chinese Longitudinal Healthy Longevity Survey for the period 1998–2012. Our results confirm that time trends and age–time interactions are important factors explaining health transitions in addition to the more commonly used age effects. We document that differences in disability and mortality rates continue to persist between urban and rural older Chinese. We also compute life expectancies and healthy life expectancies based on the proposed model as inputs for the development of aged care and financial services for older Chinese.
Seedbank Persistence of Palmer Amaranth (Amaranthus palmeri) and Waterhemp (Amaranthus tuberculatus) across Diverse Geographical Regions in the United States
Authors: Korres Nicholas E. , Norsworthy Jason K. , Young Bryan G. , Reynolds Daniel B. , Johnson William G. , Conley Shawn P. , Smeda Reid J. , Mueller Thomas C. , Spaunhorst Douglas J. , Gage Karla L. , Loux Mark , Kruger Greg R. , Bagavathiannan Muthukumar V.
Published: July 2018

Knowledge of the effects of burial depth and burial duration on seed viability and, consequently, seedbank persistence of Palmer amaranth (Amaranthus palmeriS. Watson) and waterhemp [Amaranthus tuberculatus(Moq.) J. D. Sauer] ecotypes can be used for the development of efficient weed management programs. This is of particular interest, given the great fecundity of both species and, consequently, their high seedbank replenishment potential. Seeds of both species collected from five different locations across the United States were investigated in seven states (sites) with different soil and climatic conditions. Seeds were placed at two depths (0 and 15 cm) for 3 yr. Each year, seeds were retrieved, and seed damage (shrunken, malformed, or broken) plus losses (deteriorated and futile germination) and viability were evaluated. Greater seed damage plus loss averaged across seed origin, burial depth, and year was recorded for lots tested at Illinois (51.3% and 51.8%) followed by Tennessee (40.5% and 45.1%) and Missouri (39.2% and 42%) forA. palmeriandA. tuberculatus, respectively. The site differences for seed persistence were probably due to higher volumetric water content at these sites. Rates of seed demise were directly proportional to burial depth (α=0.001), whereas the percentage of viable seeds recovered after 36 mo on the soil surface ranged from 4.1% to 4.3% compared with 5% to 5.3% at the 15-cm depth forA. palmeriandA. tuberculatus, respectively. Seed viability loss was greater in the seeds placed on the soil surface compared with the buried seeds. The greatest influences on seed viability were burial conditions and time and site-specific soil conditions, more so than geographical location. Thus, management of these weed species should focus on reducing seed shattering, enhancing seed removal from the soil surface, or adjusting tillage systems.
Temporal Variation of Solar Wind in Controlling Solar Wind‐Magnetosphere‐Ionosphere Energy Budget
Authors: Liu Jing , Wang Wenbin , Zhang Binzheng , Huang Chaosong , Lin Dong
Published: July 2018

Periodic oscillations associated with Alfven waves with periods ranging from several tens of minutes to several hours are commonly seen in the solar wind. It is not yet known how the solar wind oscillation frequency, and thus its temporal variation, regulates the energy flow through the coupled solar wind‐magnetosphere‐ionosphere‐thermosphere system. Utilizing the Coupled Magnetosphere‐Ionosphere‐Thermosphere Model driven by solar wind and interplanetary magnetic field (IMF), we have analyzed the magnetosphere‐ionosphere‐thermosphere system response to IMF Bz oscillations with periods of 10, 30, and 60 min from the perspective of energy budget. Our results indicate that the energy flow from the solar wind to geospace depends on the IMF Bz oscillation frequency. The energy coupling efficiency, defined as the ratio of the globally integrated joule heating to Akasofu's Epsilon function, is higher for lower frequency IMF Bz oscillations. Joule heating in the upper atmosphere depends not only on directly driven processes due to solar wind variability but also on the intrinsic dynamics of the magnetosphere (i.e., loading‐unloading process). This work highlights the critical role of solar wind and IMF temporal variation and the inductive inertia and resistance of coupled magnetosphere‐ionosphere system in controlling the energy transfer in the coupled solar wind‐geospace system, which has not been explored before.
Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean
Authors: Scheifele Benjamin , Waterman Stephanie , Merckelbach Lucas , Carpenter Jeffrey R.
Published: July 2018

We compare estimates of the turbulent dissipation rate, ε, obtained independently from coincident measurements of shear and temperature microstructure in the southeastern Beaufort Sea, a strongly stratified, low‐energy environment. The measurements were collected over 10 days in 2015 by an ocean glider equipped with microstructure instrumentation; they yield 28,575 shear‐derived and 21,577 temperature‐derived ε estimates. We find agreement within a factor of 2 from the two types of estimates when ε exceeds 3 × 10−11 W/kg, a threshold we identify as the noise floor of the shear‐derived estimates. However, the temperature‐derived estimates suggest that the dissipation rate is lower than this threshold in 58% of our observations. Further, the noise floor of the shear measurements artificially skews the statistical distribution of ε below 10−10 W/kg, that is, in 70% of our observations. The shear measurements overestimate portions of the geometric mean vertical profile of ε by more than an order of magnitude and underestimate the overall variability of ε by at least 2 orders of magnitude. We further discuss uncertainties that arise in both temperature‐ and shear‐derived ε estimates in strongly stratified, weakly turbulent conditions, and we demonstrate how turbulence spectra are systematically modified by stratification under these conditions. Using evidence from the temperature‐gradient spectral shapes and from the observed ε distributions, we suggest that the temperature‐derived dissipation rates are reliable to values as small as 2 × 10−12 W/kg, making them preferable for characterizing the turbulent dissipation rates in the weakly turbulent environment of this study.
Evaluation of Warm‐Core Structure in Reanalysis and Satellite Data Sets Using HS3 Dropsonde Observations: A Case Study of Hurricane Edouard (2014)
Authors: Gao Si , Wang Delong , Hong Haixu , Wu Naigeng , Li Tim
Published: July 2018

Using National Aeronautics and Space Administration Hurricane and Severe Storm Sentinel (HS3) dropsonde observations in the eye of Hurricane Edouard (2014), its warm‐core structure in reanalysis/analysis and satellite data sets are evaluated. All of the data sets generally underestimate the warm‐core strength of Edouard. Advanced Microwave Sounding Unit‐A shows the smallest error in the upper troposphere but the largest error in the lower troposphere. Its successor, Advanced Technology Microwave Sounder, significantly improves the representation of low‐level warming while maintaining its performance in the middle and upper troposphere. Two versions of the Global Forecast System analysis at different resolutions and Climate Forecast System Reanalysis version 2 show better performance than the other reanalyses. Modern Era Retrospective Analysis for Research and Application (MERRA)‐2, Japanese 55‐year Reanalysis, and European Centre for Medium‐Range Weather Forecasts Interim Reanalysis could represent the vertical warm‐core structure, but they markedly underestimate the warm‐core strength. MERRA and North American Regional Reanalysis (especially North American Regional Reanalysis) have the worst skills when reproducing warm cores. MERRA‐2 considerably outperforms its predecessor, MERRA. The warm‐core evolution of Edouard in six reanalysis/analysis data sets is diagnosed and compared. Different physical processes such as diabatic heating and vertical and horizontal advection may be responsible for warm‐core generation at different stages during its lifetime. The inaccurate representation of these physical processes in the reanalyses/analyses results in errors in the warm‐core strength and height. It is suggested that vortex relocation/bogusing, assimilation of tropical cyclone (TC) observation data, and model parameterizations are important to adequately represent warm cores in terms of strength and three‐dimensional structure. This study can shed some light on the selection of suitable data sets for estimating the real‐time warm‐core strength or for TC‐related climate studies. The need for better observations of TCs and model improvements is also highlighted.
Creeping Along the Guanxian‐Anxian Fault of the 2008 Mw 7.9 Wenchuan Earthquake in the Longmen Shan, China
Authors: He X. L. , Li H. B. , Wang H. , Zhang L. , Xu Z. Q. , Si J. L.
Published: July 2018

Crustal active faults can slip either steadily by aseismic creep, or abruptly by earthquake rupture. Creep can continuously relax the stress and reduce the magnitude of earthquakes. Identifying the slip behavior of active faults plays a crucial role in predicting and preventing earthquake disasters. Here we carried out multiscale structural analyses of fault rocks from the Guanxian‐Anxian fault zone (GAF) surface rupture of the 2008 Mw 7.9 Wenchuan earthquake (Longmen Shan thrust belt, China), and from the 3rd pilot borehole of the Wenchuan earthquake Fault Scientific Drilling project (WFSD‐3P). Results revealed that distributed R1 shears, pressure solution seams, partly dissolved clasts and mineral grains (e.g., quartz and albite), and newly formed phyllosilicate minerals all prevail in the clay‐rich fault rocks at different depths. Microstructural observations combined with X‐ray diffraction analysis show that the majority of clay minerals in the fault gouges were newly formed by pressure solution. The growth of new phyllosilicates prevents soluble grains from coalescing, thereby maintaining fast diffusive paths along solution seams, which promotes the formation of pressure solution. Both weak phyllosilicate minerals and pressure solution can control aseismic creep. Therefore, the slip behavior of the GAF is dominated by long‐term aseismic creep due to the interplay between new phyllosilicate minerals and pressure solution. Based on P wave velocity and strata distribution, we propose a model in which the GAF is creeping at shallow depths and locked at greater depths, as a possible explanation for the Wenchuan earthquake rupture mechanism.
On the Anthropogenic Impact on Long‐Term Evolution of Noctilucent Clouds
Authors: Lübken Franz‐Josef , Berger Uwe , Baumgarten Gerd
Published: July 2018

Little is known about climate change effects in the transition region between the Earth's atmosphere and space, roughly at 80–120 km. Some of the earliest observations in this region come from noctilucent clouds (NLC) at ∼83‐km altitude. There is a long‐standing dispute whether NLC are indicators of climate change. We use model simulations for a time period of 138 years to study the impact of increasing CO2 and H2O on the development of NLC on centennial time scales. Since the beginning of industrialization the water vapor concentration mixing ratio at NLC heights has increased by ∼40% (1 ppmv) due to methane increase, whereas temperatures are nearly constant. The H2O increase has led to a large enhancement of NLC brightness. NLC presumably existed centuries earlier, but the chance to observe them by the naked eye was extremely small before the twentieth century, whereas it is likely to see several NLC per season in the modern era.
A Directional Crack Damage Memory Effect in Sandstone Under True Triaxial Loading
Authors: Browning John , Meredith Philip G. , Stuart Christopher , Harland Sophie , Healy David , Mitchell Thomas M.
Published: July 2018

Crack damage leading to failure in rocks can be accumulated through cyclic stressing in the crust. However, the vast majority of experimental studies to investigate cyclic stressing apply conventional triaxial stress states (σ1 > σ2 = σ3), while in nature the state of stress in the crust is generally truly triaxial (σ1 > σ2 > σ3). Furthermore, the magnitude of these crustal stresses can vary over time and their orientations can also rotate over time, generating multiple crack populations and bulk anisotropic crack damage. We investigate the evolution of crack damage under both conventional and true triaxial stress conditions by sequentially and cyclically varying stresses in all three principal directions on cubic samples of dry sandstone using independently controlled stress paths. We have measured, simultaneously with stress, the bulk acoustic emission output, as a proxy for crack damage. We report a directionally controlled crack damage memory effect which has implications for the approach to failure in complex tectonic stress environments.
Characteristics of Radio Emissions Associated With Terrestrial Gamma‐Ray Flashes
Authors: Mailyan B. G. , Nag A. , Murphy M. J. , Briggs M. S. , Dwyer J. R. , Rison W. , Krehbiel P. R. , Boggs L. , Bozarth A. , Cramer E. S. , Roberts O. J. , Stanbro M. , Rassoul H. K.
Published: July 2018

In this study, we analyze 44 terrestrial gamma‐ray flashes (TGFs) detected by the Fermi Gamma‐ray Burst Monitor (GBM) occurring in 2014–2016 in conjunction with data from the U.S. National Lightning Detection Network (NLDN). We examine the characteristics of magnetic field waveforms measured by NLDN sensors for 61 pulses that occurred within 5 ms of the start‐time of the TGF photon flux. For 21 (out of 44) TGFs, the associated NLDN pulse occurred almost simultaneously with (that is, within 200 μs of) the TGF. One TGF had two NLDN pulses within 200 μs. The median absolute time interval between the beginning of these near‐simultaneous pulses and the TGF flux start‐time is 50 μs. We speculate that these RF pulses are signatures of either TGF‐associated relativistic electron avalanches or currents traveling in conducting paths “preconditioned” by TGF‐associated electron beams. Compared to pulses that were not simultaneous with TGFs (but within 5 ms of one), simultaneous pulses had higher median absolute peak current (26 kA versus 11 kA), longer median threshold‐to‐peak rise time (14 μs versus 2.8 μs), and longer median peak‐to‐zero time (15 μs versus 5.5 μs). A majority (77%) of our simultaneous RF pulses had NLDN‐estimated peak currents less than 50 kA indicating that TGF emissions can be associated with moderate‐peak‐amplitude processes. The lightning flash associated with one of the TGFs in our data set was observed by a Lightning Mapping Array, which reported a relatively high‐power source at an altitude of 25 km occurring 101 μs after the GBM‐reported TGF discovery‐bin start‐time.
Gas Transfer Velocities Evaluated Using Carbon Dioxide as a Tracer Show High Streamflow to Be a Major Driver of Total CO2 Evasion Flux for a Headwater Stream
Authors: McDowell Mollie J. , Johnson Mark S.
Published: July 2018

Evasion of carbon dioxide (CO2) from headwater streams is a dominant process controlling the fate of terrestrially derived carbon in inland waters. However, limitations of sampling techniques inhibit efforts to accurately characterize CO2 evasion from streams, and particularly headwater streams with steep gradients, complex morphologies, and challenging terrain. CO2 source dynamics coupled with turbulence conditions control gas transfer velocities of CO2 (
) and therefore drive CO2 evasion. We present estimates of
and CO2 evasion from a steep, turbulent headwater stream in southwestern British Columbia, Canada, collected using an automated in situ CO2 tracer technique. Gas transfer velocities scaled positively with discharge, with a median
of 36.8 m/day and a range of 13.5 to 169 m/day. Gas transfer velocities were highest during high‐flow events, with 84% of all CO2 emissions occurring when discharge was higher than Q50, the median discharge (92.6 L/s). Widely used models overestimated gas transfer velocities with a mean relative error of 24% but underestimated k600 values above 165 m/day. Our determinations of gas transfer velocities for a range of streamflow suggest that CO2 evasion may be higher than previously estimated from direct measurements or models, particularly during high‐flow events. These findings illustrate the need for direct, frequent, in situ determinations of
to accurately characterize CO2 evasion dynamics in steep headwater streams.
Early Eocene Thermal Maximum 3: Biotic Response at Walvis Ridge (SE Atlantic Ocean)
Authors: Thomas Ellen , Boscolo‐Galazzo Flavia , Balestra Barbara , Monechi Simonetta , Donner Barbara , Röhl Ursula
Published: July 2018

We combine stable isotope, calcareous nannoplankton, and benthic foraminiferal records for Ocean Drilling Program Sites 1262 (paleodepth ~3,500 m) and 1263 (paleodepth ~1,500 m) on Walvis Ridge (SE Atlantic), to document the marine biotic response to Eocene Thermal Maximum 3, in the early part of the Early Eocene Climate Optimum, ~3.1 Myr after the Paleocene/Eocene Thermal Maximum. Bottom water warming may have decreased the vertical thermal gradient at both sites, but more at Site 1263 than at Site 1262. Floral and faunal changes were more muted at Site 1262 than at shallower Site 1263, indicating that carbonate dissolution was not the most important cause of biotic effects. Assemblage changes were more pronounced in benthos than in plankton. Calcareous nannofossils underwent minor ecological changes, possibly related to the presence of warmer waters, especially at Site 1263, and dissolution‐resistant taxa increased in abundance. Benthic foraminiferal diversity decreased at both sites, but benthic foraminiferal accumulation rates declined dramatically at Site 1263, remaining stable at Site 1262. Ocean circulation may have changed during ETM3, resulting in the presence of a warmer (intermediate) water mass at Site 1263. More pronounced warming may have caused enhanced remineralization of organic matter, so less food reached the benthos. The biotic response to the X‐event was less pronounced than that to earlier and more severe hyperthermal events, the Paleocene/Eocene Thermal Maximum and Eocene Thermal Maximum 2. The extent of the biotic response reflects the severity of the environmental disturbance but varies by location (e.g., paleodepth on Walvis Ridge).
Personality Dynamics, Motivation, and the Logic of Explanation
Authors: Boag Simon
Published: July 2018

Dynamic personality approaches provide an important step forward for twenty-first century personality theories because they promise greater explanatory power compared with latent trait approaches. Nevertheless, whether dynamic personality theories satisfactorily address motivated action remains unclear. To address this, this article discusses the logic of explanation and problems with latent trait approaches in terms of circularity and reification. The article then assesses explanation within dynamic personality accounts and the putative role of motivation. While dynamic personality approaches avoid many of the problems associated with latent trait accounts, a satisfactory account of motivational systems and “human nature” is currently missing. Suggestions for addressing the dynamics of human nature in terms of criteria for motivational systems are discussed. Attachment theory is offered as one possible foundation for addressing the motivational dynamics of personality.
Co-treatment of TGF-β3 and BMP7 is superior in stimulating chondrocyte redifferentiation in both hypoxia and normoxia compared to single treatments
Authors: Huang Xiaobin , Zhong Leilei , Post Janine N. , Karperien Marcel
Published: July 2018

Signaling by members of the transforming growth factor-β (TGF-β) superfamily, such as TGF-β3 and BMP7, and oxygen tension play a pivotal role in chondrocyte biology. The objective of this research was to investigate the endogenous BMP7 expression in human osteoarthritis (OA) cartilage and the effect of oxygen tension on the single or combined treatment with TGF-β3 and BMP7 on OA chondrocyte redifferentiation in three dimensional (3D) pellet cultures. The results showed the expression of BMP7 and its intracellular signaling target SMAD1/5/8 was decreased in early OA, while it was increased in later stages of OA. The combined treatment with TGF-β3 and BMP7, both in normoxia and hypoxia, was more effective than TGF-β3 or BMP7 alone in redifferentiating chondrocytes. This was reflected by Alcian blue/Safranin O staining and collagen type II protein expression, as well as by gene expression. Hypoxia elevated TGF-β3 and BMP7-induced matrix formation of OA chondrocytes and alleviated the catabolic gene expression. Interestingly, cells cultured under normoxia displayed mild signs of an inflammatory stress response, which was effectively counteracted by culturing the cells under low oxygen tension. Our data underscores the important modulatory role of oxygen tension on the chondrocyte’s responsiveness to TGF-β3 and/or BMP7.
Knee Joint Tissues Effectively Separate Mixed Sized Molecules Delivered in a Single Bolus to the Heart
Authors: Ngo Lucy , Knothe Lillian E. , Knothe Tate Melissa L.
Published: July 2018

The role of molecular size selectivity in the onset and progression of osteoarthritis (OA), a degenerative disease of the musculoskeletal system and the most common cause of disability in aging adults, is unknown. Here we delivered a mixture of Texas-red (70 kDa), and Rhodamine-green (10 kDa) tagged, dextrans of neutral charge in a single bolus via heart injection to middle aged (8–10 months) and aged (17–19 months) Dunkin-Hartley Guinea pigs, a natural model for OA. We quantified tracer transport in serial-sectioned, cryofixed block specimens after five minutes’ circulation. A remarkable separation of the molecules was observed in serial fluorescent images of whole joint sections. The larger, 70 kDa red tracer was abundant in the marrow cavity albeit less prevalent or absent in the bone, cartilage, meniscus and other tissues of the joint. Tissues of the meniscus, ligament, and tendon exhibited abundant 10 kDa tracer; volumes of tissue containing this molecular tracer were significantly lower in older than in younger animals. Surprisingly, muscle fiber bundles exhibited little fluorescence, while their bounding fasciae fluoresced either red or green. Small caliber channels through the articular cartilage appeared to show a degree of green fluorescence not observed in the surrounding cartilage matrix. This study opens up new avenues for study of musculoskeletal physiology in health and disease as well as new strategies for drug delivery.
Crossover from Jamming to Clogging Behaviours in Heterogeneous Environments
Authors: Péter H. , Libál A. , Reichhardt C. , Reichhardt C. J. O.
Published: July 2018

Jamming describes a transition from a flowing or liquid state to a solid or rigid state in a loose assembly of particles such as grains or bubbles. In contrast, clogging describes the ceasing of the flow of particulate matter through a bottleneck. It is not clear how to distinguish jamming from clogging, nor is it known whether they are distinct phenomena or fundamentally the same. We examine an assembly of disks moving through a random obstacle array and identify a transition from clogging to jamming behavior as the disk density increases. The clogging transition has characteristics of an absorbing phase transition, with the disks evolving into a heterogeneous phase-separated clogged state after a critical diverging transient time. In contrast, jamming is a rapid process in which the disks form a homogeneous motionless packing, with a rigidity length scale that diverges as the jamming density is approached.