bluuebunny/crossref_metadata_2025_split huggingface dataset:
Post‐depositional processes: What really happens to new atmospheric iron in the ocean's surface?
Authors: Bressac Matthieu , Guieu Cécile 
Published: August 2013

AbstractAbiotic iron removal processes such as scavenging can significantly and rapidly modify iron distribution in the dissolved‐colloidal‐particulate continuum. Therefore, these processes could be considered, in addition to ligand complexation, as a major control on atmospheric iron dissolution in seawater. In this work, we investigated the seasonal abiotic processes occurring once dust deposited on surface seawater using a series of artificial seeding experiments (allowing us to take into consideration the settling of particles on a 1 m depth layer). Here, we demonstrate that atmospheric dissolved iron concentration ([DFe]) is driven by the processes governed by the dissolved organic matter (DOM) pool. Following artificial dust seeding, an order magnitude range increase in the [DFe] (12 – 181 nmol L−1) was observed depending on the season. Under high and fresh DOM conditions (spring and summer), the rapid formation of aggregates induced a negative feedback on the [DFe] through scavenging, while a fraction of the DFe was likely organically complexed. In contrast, in low‐DOM surface waters (winter), aggregation was not observed, allowing a very large transient increase in [DFe] (181 nmol L−1) before being removed by adsorption onto settling particles. A key result of the findings is that depending on the age and quantity of DOM, the “lithogenic carbon pump” is likely a major pathway for organic carbon export. Modeling studies should therefore relate both atmospheric iron dissolution in seawater and the intensity of the subsequent biological response, to the age and quantity of DOM.
Hepatocytes as a Source of Cholangiocytes in Injured Liver
Authors: Lemaigre Frédéric P. 
Published: August 2013

Abstract

Cellular reprogramming—the ability to interconvert distinct cell types with defined factors—is transforming the field of regenerative medicine. However, this phenomenon has rarely been observed

in vivo

without exogenous factors. Here, we report that activation of Notch, a signaling pathway that mediates lineage segregation during liver development, is sufficient to reprogram hepatocytes into biliary epithelial cells (BECs). Moreover, using lineage tracing, we show that hepatocytes undergo widespread hepatocyte-to-BEC reprogramming following injuries that provoke a biliary response, a process requiring Notch. These results provide direct evidence that mammalian regeneration prompts extensive and dramatic changes in cellular identity under injury conditions.
The effect of early‐life stress on memory systems supporting instrumental behavior
Authors: Patterson Tara K. , Craske Michelle G. , Knowlton Barbara J. 
Published: August 2013

ABSTRACTPeople experiencing early‐life stress (ELS) exhibit increased incidence of behaviors that lead to addiction and obesity as adults. Many of these behaviors may be viewed as resulting from an overreliance on habits as opposed to goal‐directed instrumental behavior. This increased habitization may result from alterations in the interactions between dorsolateral striatum‐dependent and hippocampus‐dependent learning systems. As an initial examination of this idea, we investigated the effect of ELS on instrumental learning and extinction. In Experiment 1, we examined the effect of ELS in two groups of people, one trained on a continuous reinforcement schedule and one trained on a partial reinforcement schedule. We found that people who experienced ELS had a diminished effect of the partial reinforcement schedule on extinction. In Experiment 2, we again manipulated reinforcement schedule and also challenged declarative memory by requiring subjects to perform a concurrent task. We found that the declarative challenge did not affect extinction responding in the non‐ELS group. In a moderate‐ELS group, we observed a diminished sensitivity to the reinforcement schedule during extinction only under divided attention. In the high‐ELS group, we observed a reduced sensitivity to reinforcement schedule even in the absence of the declarative memory challenge, consistent with Experiment 1. Our results suggest that ELS reduces the tendency to use declarative, hippocampus‐dependent memory in instrumental tasks in favor of habits. ELS may affect hippocampal development, thus altering the interaction between memory systems and potentially contributing to poor health outcomes. © 2013 Wiley Periodicals, Inc.
Hippocampus and striatum: Dynamics and interaction during acquisition and sleep‐related motor sequence memory consolidation
Authors: Albouy Geneviève , King Bradley R. , Maquet Pierre , Doyon Julien 
Published: August 2013

ABSTRACTWhile several models of memory consolidation have previously associated hippocampal activity with declarative memory, there is now increasing evidence that the hippocampus also plays a crucial role in procedural memory. Here, we review recent human functional neuroimaging studies demonstrating that the hippocampus is involved in the acquisition and sleep‐related consolidation of procedural memories, and motor sequence‐based skills in particular. More specifically, we present evidence that hippocampal activity and its functional interactions with other brain structures, particularly competition with the striatum, contribute to initial learning of sequential motor behavior. Interestingly, these early cerebral representations in the hippocampus and striatum, which may interact through the prefrontal cortex, can even predict subsequent sleep‐related memory consolidation processes. We propose that sleep can reorganize the activity within, as well as the functional interactions between, these structures, ultimately favoring overnight performance enhancement. Finally, we conclude by offering insights into the respective roles of these structures in procedural memory consolidation processes. We argue that, in the context of motor sequence memory consolidation, the hippocampal system triggers subsequent sleep‐dependent performance enhancement whereas the striatal system is involved in the maintenance of the motor behavior over time. © 2013 Wiley Periodicals, Inc.
Evaluating the ability of a hydrologic model to replicate hydro‐ecologically relevant indicators
Authors: Shrestha Rajesh R. , Peters Daniel L. , Schnorbus Markus A. 
Published: August 2013

AbstractIt is a common practice to employ hydrologic models for assessing alterations to streamflow as a result of anthropogenically driven changes, such as riverine, land use, and climate change. However, the ability of the models to replicate different components of the hydrograph simultaneously is not clear. Hence, this study evaluates the ability of a standard hydrologic model set‐up: Variable Infiltration Capacity (VIC) hydrologic model for two headwater sub‐basins in the Fraser River (Salmon and Willow), British Columbia, Canada, with climate inputs derived from observations and statistically downscaled global climate models (GCMs); to simulate six general water resource indicators (WRIs) and 32 ecologically relevant indicators of hydrologic alterations (IHA). The results show a generally good skill of the observation‐driven VIC model in replicating most of the WRIs and IHAs. Although the WRIs, including annual volume, centre of timing, and seasonal flows, and the IHAs, including maximum and minimum flows, were reasonably well replicated, statistically significant differences in some of the monthly flows, number and duration of flow pulses, rise and fall rates, and reversals were noted. In the case of GCM‐driven results, additional monthly, maximum, and minimum flow indicators produced statistically significant differences. A number of issues with the model input/output data, hydrologic model parametrization and structure as well as downscaling methods were identified, which lead to such discrepancies. Therefore, there is a need to exercise caution in the use of model‐simulated indicators. Overall, the WRIs and IHAs can be useful tools for evaluating changes in an altered hydrologic system, provided the skill and limitations of the model in replicating these indicators are understood. © 2013 Her Majesty the Queen in Right of Canada. Hydrological Processes © 2013 John Wiley & Sons Ltd.
Supramolecular Nanofibers of Peptide Amphiphiles for Medicine
Authors: Webber Matthew J. , Berns Eric J. , Stupp Samuel I. 
Published: August 2013

AbstractPeptide nanostructures are an exciting class of supramolecular systems that can be designed for novel therapies with great potential in advanced medicine. This paper reviews progress on nanostructures based on peptide amphiphiles capable of forming one‐dimensional assemblies that emulate in structure the nanofibers present in extracellular matrices. These systems are highly tunable using supramolecular chemistry, and can be designed to signal cells directly with bioactive peptides. Peptide amphiphile nanofibers can also be used to multiplex functions through co‐assembly and designed to deliver proteins, nucleic acids, drugs, or cells. We illustrate here the functionality of these systems, describing their use in regenerative medicine of bone, cartilage, the nervous system, the cardiovascular system, and other tissues. In addition, we highlight recent work on the use of peptide amphiphile assemblies to create hierarchical biomimetic structures with order beyond the nanoscale, and also discuss the future prospects of these supramolecular systems.
Progesterone reduces the expression of spinal cyclooxygenase‐2 and inducible nitric oxide synthase and prevents allodynia in a rat model of central neuropathic pain
Authors: Coronel M.F. , Labombarda F. , De Nicola A.F. , González S.L. 
Published: August 2013

AbstractBackgroundSpinal cord injury (SCI) results in the development of chronic pain that is refractory to conventional treatment. Progesterone, a neuroprotective steroid, may offer a promising perspective in pain modulation after central injury. Here, we explore the impact of progesterone administration on the post‐injury inflammatory cascade involving the enzymes cyclooxygenase‐2 (COX‐2) and inducible nitric oxide synthase (iNOS) at the spinal cord level. We also analyse pain behaviours, the profile of glial cell activation, and IκB‐α mRNA levels, as an index of NF‐κB transactivation.MethodsWe used biochemical, immunohistochemical and molecular techniques, as well as behavioural studies, to investigate the effects of progesterone in a well‐characterized model of central neuropathic pain.ResultsInjured animals receiving progesterone presented reduced mRNA levels of the proinflammatory enzymes, as well as decreased COX‐2 activity and nitrite levels, as compared to vehicle‐treated injured rats. Further, animals receiving the steroid exhibited lower levels of IκB‐α mRNA, suggesting decreased NF‐κB transactivation. Progesterone administration also attenuated the injury‐induced increase in the number of glial fibrillary acidic protein and OX‐42 positive cells both at early and late time points after injury, and prevented the development of mechanical and thermal allodynia. Further, when injured rats received early progesterone administration for a critical period of time after injury, they did not display allodynic behaviours even after the treatment had stopped.ConclusionsOur results suggest that progesterone, by modulating early neuroinflammatory events triggered after SCI, may represent a useful strategy to prevent the development of central chronic pain.
Spermine‐alt‐poly(ethylene glycol) polyspermine as a safe and efficient aerosol gene carrier for lung cancer therapy
Authors: Kim You‐Kyoung , Cho Chong‐Su , Cho Myung‐Haing , Jiang Hu‐Lin 
Published: August 2013

AbstractThe clinical success of gene therapy critically depends upon the safety and efficiency of delivery system used. Although polyethylenimine (PEI) has been commonly used as an efficient cationic polymeric gene carrier due to its high transfection efficiency, its cytotoxicity and nondegradability limit the polymer's therapeutic applications in clinical trials. In this study, biocompatible polyspermine based on spermine (SPE) and poly(ethylene glycol) (PEG) diacrylate (SPE‐alt‐PEG) was synthesized using a Michael‐type addition reaction, and its ability as an alternative gene carrier for lung cancer therapy was evaluated. SPE‐alt‐PEG polyspermine was complexed with plasmid DNA, and the resulting complexes were characterized by particle size and surface charge by dynamic light scattering, complex formation and DNA protection ability by gel retardation, and complex shape by energy‐filtering transmission electron microscopy. The SPE‐alt‐PEG copolymer showed low cytotoxicity, and SPE‐alt‐PEG/DNA complexes showed efficacious transfection efficiency compared with 25 kDa PEI (PEI 25K). Also SPE‐alt‐PEG/GFP complexes were efficiently transferred into the lungs after aerosol administration without toxicity, and delivery of Pdcd4 gene as a therapeutic gene with SPE‐alt‐PEG polyspermine greatly reduced tumor size as well as tumor numbers in K‐rasLA1 lung cancer model mice compared relative to the effect observed for PEI 25K. These results suggest that SPE‐alt‐PEG has potential as a gene carrier for lung cancer gene therapy. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 102A: 2230–2237, 2014.
Bone Loss After Bariatric Surgery: Discordant Results Between DXA and QCT Bone Density
Authors: Yu Elaine W , Bouxsein Mary L , Roy Adam E , Baldwin Chantel , Cange Abby , Neer Robert M , Kaplan Lee M , Finkelstein Joel S 
Published: August 2013

ABSTRACT

Several studies, using dual-energy X-ray absorptiometry (DXA), have reported substantial bone loss after bariatric surgery. However, profound weight loss may cause artifactual changes in DXA areal bone mineral density (aBMD) results. Assessment of volumetric bone mineral density (vBMD) by quantitative computed tomography (QCT) may be less susceptible to such artifacts. We assessed changes in BMD of the lumbar spine and proximal femur prospectively for 1 year using DXA and QCT in 30 morbidly obese adults undergoing Roux-en-Y gastric bypass surgery and 20 obese nonsurgical controls. At 1 year, subjects who underwent gastric bypass surgery lost 37 ± 2 kg compared with 3 ± 2 kg lost in the nonsurgical controls (p &lt; 0.0001). Spine BMD declined more in the surgical group than in the nonsurgical group whether assessed by DXA (−3.3 versus −1.1%, p = 0.034) or by QCT (−3.4 versus 0.2%, p = 0.010). Total hip and femoral neck aBMD declined significantly in the surgical group when assessed by DXA (−8.9 versus −1.1%, p &lt; 0.0001 for the total hip and −6.1 versus −2.0%, p = 0.002 for the femoral neck), but no changes in hip vBMD were noted using QCT. Within the surgical group, serum P1NP and CTX levels increased by 82% ± 10% and by 220% ± 22%, respectively, by 6 months and remained elevated over 12 months (p &lt; 0.0001 for all). Serum calcium, vitamin D, and PTH levels remained stable in both groups. We conclude that moderate vertebral bone loss occurs in the first year after gastric bypass surgery. However, striking declines in DXA aBMD at the proximal femur were not confirmed with QCT vBMD measurements. These discordant results suggest that artifacts induced by large changes in body weight after bariatric surgery affect DXA and/or QCT measurements of bone, particularly at the hip. © 2014 American Society for Bone and Mineral Research.
Deletion of a Single β-Catenin Allele in Osteocytes Abolishes the Bone Anabolic Response to Loading
Authors: Javaheri Behzad , Stern Amber Rath , Lara Nuria , Dallas Mark , Zhao Hong , Liu Ying , Bonewald Lynda F , Johnson Mark L 
Published: August 2013

ABSTRACT

The Wnt/β-catenin signaling pathway is essential for bone cell viability and function and for skeletal integrity. To determine if β-catenin in osteocytes plays a role in the bone anabolic response to mechanical loading, 18- to 24-week-old osteocyte β-catenin haploinsufficient mice (Dmp1-Cre × β-catenin fl/ + ; HET cKO) were compared with their β-catenin fl/fl (control) littermates. Trabecular bone volume (BV/TV) was significantly less (58.3%) in HET cKO females versus controls, whereas male HET cKO and control mice were not significantly different. Trabecular number was significantly less in HET cKO mice compared with controls for both genders, and trabecular separation was greater in female HET cKO mice. Osteoclast surface was significantly greater in female HET cKO mice. Cortical bone parameters in males and females showed subtle or no differences between HET cKO and controls. The right ulnas were loaded in vivo at 100 cycles, 2 Hz, 2500 µϵ, 3 days per week for 3 weeks, and the left ulnas served as nonloaded controls. Calcein and alizarin complexone dihydrate were injected 10 days and 3 days before euthanization, respectively. Micro-computed tomography (µCT) analysis detected an 8.7% and 7.1% increase in cortical thickness in the loaded right ulnas of male and female control mice, respectively, compared with their nonloaded left ulnas. No significant increase in new cortical bone formation was observed in the HET cKO mice. Histomorphometric analysis of control mice showed a significant increase in endocortical and periosteal mineral apposition rate (MAR), bone-formation rate/bone surface (BFR/BS), BFR/BV, and BFR/TV in response to loading, but no significant increases were detected in the loaded HET cKO mice. These data show that deleting a single copy of β-catenin in osteocytes abolishes the anabolic response to loading, that trabecular bone in females is more severely affected and suggest that a critical threshold of β-catenin is required for bone formation in response to mechanical loading. © 2014 American Society for Bone and Mineral Research
Age‐related change in renal corticomedullary differentiation: Evaluation with noncontrast‐enhanced steady‐state free precession (SSFP) MRI with spatially selective inversion pulse using variable inversion time
Authors: Noda Yasufumi , Kanki Akihiko , Yamamoto Akira , Higashi Hiroki , Tanimoto Daigo , Sato Tomohiro , Higaki Atsushi , Tamada Tsutomu , Ito Katsuyoshi 
Published: August 2013

PurposeTo evaluate age‐related change in renal corticomedullary differentiation and renal cortical thickness by means of noncontrast‐enhanced steady‐state free precession (SSFP) magnetic resonance imaging (MRI) with spatially selective inversion recovery (IR) pulse.Materials and MethodsThe Institutional Review Board of our hospital approved this retrospective study and patient informed consent was waived. This study included 48 patients without renal diseases who underwent noncontrast‐enhanced SSFP MRI with spatially selective IR pulse using variable inversion times (TIs) (700–1500 msec). The signal intensity of renal cortex and medulla were measured to calculate renal corticomedullary contrast ratio. Additionally, renal cortical thickness was measured.ResultsThe renal corticomedullary junction was clearly depicted in all patients. The mean cortical thickness was 3.9 ± 0.83 mm. The mean corticomedullary contrast ratio was 4.7 ± 1.4. There was a negative correlation between optimal TI for the best visualization of renal corticomedullary differentiation and age (r = −0.378; P = 0.001). However, there was no significant correlation between renal corticomedullary contrast ratio and age (r = 0.187; P = 0.20). Similarly, no significant correlation was observed between renal cortical thickness and age (r = 0.054; P = 0.712).ConclusionIn the normal kidney, noncontrast‐enhanced SSFP MRI with spatially selective IR pulse can be used to assess renal corticomedullary differentiation and cortical thickness without the influence of aging, although optimal TI values for the best visualization of renal corticomedullary junction were shortened with aging. J. Magn. Reson. Imaging 2014;40:79–83. © 2013 Wiley Periodicals, Inc.
Trends in seasonal surface air temperature in mainland Portugal, since 1941
Authors: Espírito Santo Fátima , de Lima M. Isabel P. , Ramos Alexandre M. , Trigo Ricardo M. 
Published: August 2013

ABSTRACTThis study provides a thorough assessment of recent changes in near‐surface air temperature in mainland Portugal at both the local and regional level, focusing on extreme events (maximum and minimum) at a seasonal scale. It examines trends in selected specific indices that are calculated from daily air temperature data from 23 measuring stations scattered across the territory, recorded between 1941 and 2006. The results show overall warming trends over mainland Portugal that are consistent with the dominant global warming and reflect an increase in both maximum and minimum air temperature. When we split the study period into two sub‐periods, 1945–1975 and 1976–2006, the partial trend analysis reveals that the first sub‐period is mostly characterized by cooling followed by an even stronger tendency towards warmer benchmarks in all the indices evaluated, in particular for the warm‐related temperature extremes in spring and summer.The changes observed in seasonal patterns confirm the well‐known asymmetries in the climate in mainland Portugal and suggest that they are likely to be aggravated. There are changes associated with extreme temperatures, in particular, the significant increase in the frequency and duration of heat waves, and the increase in the frequency of hot days and tropical nights, especially in spring and summer; moreover there is a significant decrease in the frequency of cold waves and frost days.Teleconnections associated with changing patterns of temperature are also investigated. The results show that, over mainland Portugal, cold‐related air temperature extremes have been associated with the East Atlantic mode in autumn, whereas warm‐related extremes have been associated with the Scandinavia teleconnection pattern in spring, summer and autumn. However, the most prominent Northern Hemisphere pattern, the North Atlantic Oscillation, exerts limited influence, which is felt mostly in winter and spring.
Bioactive stilbenes from Vitis vinifera grapevine shoots extracts
Authors: Chaher Nassima , Arraki Kamel , Dillinseger Elsa , Temsamani Hamza , Bernillon Stéphane , Pedrot Eric , Delaunay Jean‐Claude , Mérillon Jean‐Michel , Monti Jean‐Pierre , Izard Jean‐Claude , Atmani Djebbar , Richard Tristan 
Published: August 2013

AbstractBACKGROUNDViticultural residues from commercial viticultural activities represent a potentially important source of bioactive stilbenes such as resveratrol. The main aim of the present study was therefore to isolate, identify and perform biological assays against amyloid‐β peptide aggregation of original stilbenes from Vitis vinifera shoots.RESULTSA new resveratrol oligomer, (Z)‐cis‐miyabenol C (3), was isolated from Vitis vinifera grapevine shoots together with two newly reported oligostilbenes from Vitis vinifera shoots, vitisinol C (1) and (E)‐cis‐miyabenol C (2), and six known compounds: piceatannol, resveratrol, (E)‐ε‐viniferin (trans‐ε‐viniferin), ω‐viniferin, vitisinol C and (E)‐miyabenol C. The structures of these resveratrol derivatives were established on the basis of detailed spectroscopic analysis including nuclear magnetic resonance experiments. All the newly reported compounds were tested for their anti‐aggregative activity against amyloid‐β fibril formation. Vitisinol C was found to exert a significant activity against amyloid‐β aggregation.CONCLUSIONVitis vinifera grapevine shoots are potentially interesting as a source of new bioactive stilbenes, such as vitisinol C. © 2013 Society of Chemical Industry