bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nafion
Authors: Tang Haolin , Pan Mu 
Published: March 2015

AbstractNafion is a perfluorinated sulfonic acid resin (PFSA), which was developed by the E. I. DuPont Company. Owing to its stability, superior mechanical properties, high chemical inertness, and proton conductivity, Nafion is currently used in commercial membranes and catalyst layers of fuel cells. This article overviews the structure, morphology, and mechanical and electrochemical properties of Nafion. In addition, important research as well as practical industrial applications, such as brine electrolysis, chlor‐alkali cells, salt splitting, clean power generation by Nafion polymer electrolyte fuel cells, batteries, gas separation, gas sensors, and electrodialysis, is also presented.
Heat Resistant Polymers
Authors: Mehdipour‐Ataei Shahram , Tabatabaei‐Yazdi Zahra 
Published: March 2015

AbstractOver time human needs have been changing. Science and technology are responsible for providing these needs. One of these needs, especially in high‐tech technology is a polymer that can tolerate high temperatures. Progress in this field is due to meet the requirements of the aerospace industry, where heat‐resistant polymers with low weights and suitable formability and processability are needed to substitute many high weight metals.In this article, a brief introduction covers some basic information about heat‐resistant characteristics, factors influencing it, and some well‐established analytical methods for estimating heat‐resistant features of polymeric materials. In the following sections, a number of most important commonly used heat‐resistant polymers are selected and their overall properties are reviewed particularly focusing on their heat resistance. These polymers include polyimides and their copolymers, polyamides and related copolymers, polyesters, aromatic polyethers and their derivatives, benzimidazoles, and ladder polymers. It should be noted that a number of other heat‐resistant synthetically developed or commercially successful polymers (less important) are not included in this category, which are fully described in other books and review papers.
America's water risk: Current demand and climate variability
Authors: Devineni Naresh , Lall Upmanu , Etienne Elius , Shi Daniel , Xi Chen 
Published: March 2015

AbstractA new indicator of drought‐induced water stress is introduced and applied at the county level in the USA. Unlike most existing drought metrics, we directly consider current daily water demands and renewable daily water supply to estimate the potential stress. Water stress indices developed include the Normalized Deficit Cumulated to represent multiyear droughts by computing the maximum cumulative deficit between demand and supply over the study period (1949–2009) and the Normalized Deficit Index representing drought associated with maximum cumulative deficit each year. These water stress indices map directly to storage requirements needed to buffer multiyear and within‐year climate variability and can reveal the dependence on exogenous water transferred by rivers/canals to the area. Future climate change and variability can be also incorporated into this framework to inform climate‐driven drought for additional storage development and potential applications of water trading across counties.
The development of a bursty precipitation front with intense localized parallel electric fields driven by whistler waves
Authors: Drake J. F. , Agapitov O. V. , Mozer F. S. 
Published: March 2015

AbstractThe dynamics and structure of whistler turbulence relevant to electron acceleration in the Earth's outer radiation belt are explored with simulations and comparisons with observations. An initial state with an electron temperature anisotropy in a spatially localized domain drives whistlers which scatter electrons. An outward propagating front of whistlers and hot electrons nonlinearly evolves to form regions of intense parallel electric field with structure similar to observations. The precipitating hot electrons propagate away from the source region in intense bunches rather than as a smooth flux.
A unified approach for process‐based hydrologic modeling: 1. Modeling concept
Authors: Clark Martyn P. , Nijssen Bart , Lundquist Jessica D. , Kavetski Dmitri , Rupp David E. , Woods Ross A. , Freer Jim E. , Gutmann Ethan D. , Wood Andrew W. , Brekke Levi D. , Arnold Jeffrey R. , Gochis David J. , Rasmussen Roy M. 
Published: March 2015

AbstractThis work advances a unified approach to process‐based hydrologic modeling to enable controlled and systematic evaluation of multiple model representations (hypotheses) of hydrologic processes and scaling behavior. Our approach, which we term the Structure for Unifying Multiple Modeling Alternatives (SUMMA), formulates a general set of conservation equations, providing the flexibility to experiment with different spatial representations, different flux parameterizations, different model parameter values, and different time stepping schemes. In this paper, we introduce the general approach used in SUMMA, detailing the spatial organization and model simplifications, and how different representations of multiple physical processes can be combined within a single modeling framework. We discuss how SUMMA can be used to systematically pursue the method of multiple working hypotheses in hydrology. In particular, we discuss how SUMMA can help tackle major hydrologic modeling challenges, including defining the appropriate complexity of a model, selecting among competing flux parameterizations, representing spatial variability across a hierarchy of scales, identifying potential improvements in computational efficiency and numerical accuracy as part of the numerical solver, and improving understanding of the various sources of model uncertainty.
Transfer
RNA
Synthetase Editing of Errors in Amino Acid Selection
Authors: Jakubowski Hieronim 
Published: March 2015

Abstract

Aminoacyl‐tRNA synthetases (AARSs) define genetic code by pairing amino acids with their cognate tRNAs and maintain ‘quality control’ in the flow of information from gene to protein. Binding energies of amino acids to AARSs are often inadequate to assure the required accuracy of translation. This has necessitated the evolution of a second determinant of specificity, proofreading or editing mechanisms that remove amino acid selection errors, thereby maintaining accuracy and preventing access to the genetic code of non‐protein amino acids, including homocysteine, ornithine, homoserine and norvaline. Editing is part of the tRNA aminoacylation process in living organisms from bacteria to humans. Impaired amino acid editing reduces cell proliferation under stress conditions and can lead to disease. Despite a strong selective pressure to minimise mistranslation, some organisms possess error‐prone AARSs that cause mistranslation, which can be beneficial for pathogens by increasing their phenotypic variation essential for the evasion of host defences.

Key Concepts

Aminoacyl‐tRNA synthetases match tRNAs with corresponding amino acids, thereby translating genetic information from the nucleic acid to the protein language.

Faithful translation of the genetic information depends on editing of amino acid misactivation errors.

Editing occurs at the synthetic active site by hydrolysis of aminoacyl‐adenylates (
pre‐transfer
editing) and/or at a separate editing site by deacylation of aminoacyl‐tRNA (
post‐transfer
editing).

Access of the non‐protein amino acids, such as homocysteine, ornithine or norvaline to the genetic code is prevented by editing.

Preventing mistranslation by editing of misactivated amino acids is crucial to cellular homeostasis.

Impaired editing increases sensitivity of cells to oxidative stress and nutritional imbalance.

Some pathogenic organisms possess editing‐defective, error‐prone AARSs that cause mistranslation, which is essential for the evasion of host defences.

Synthetic biology targets AARSs to engineer new proteins containing non‐canonical amino acids (alloproteins).
F
lemming,
W
alther
Authors: Dröscher Ariane 
Published: March 2015

Abstract

Walther Flemming (1843–1906) – German histologist who made numerous important cytological discoveries. In particular, in the 1870s, he clarified the stages of karyokinesis, observed the regular distribution of the individual chromosomes and their longitudinal split during this process, coined the terms ‘chromatin’, ‘equatorial plate’ and ‘mitosis’, and pronounced the aphorism ‘
omnis nucleus e nucleo
’ (all nuclei derive from predecessor nuclei). In 1887, he was one of the first to describe meiosis, and in 1885, he detailed the breaking down of the nucleus during the process of cell death. Flemming was an excellent microscopist who, among other technical devices, developed a mixture of chromic anhydride, osmium tetroxide and acetic acid, still known as Flemming's fluid.
Ketone Bodies
Authors: Morio Beatrice , Wolfe Robert R 
Published: March 2015

Abstract

Ketone bodies are water‐soluble equivalents of fatty acids. They can substitute for glucose in peripheral tissues, especially in the brain, when glucose becomes limited in physiological and pathological states. Recent findings demonstrate that they also act as signalling metabolites, thus participating in the organism adaptation to the environment, such as during fasting, calorie restriction or prolonged exercise. Diabetes is the most common pathological cause of elevated blood ketone bodies. Ketone bodies are produced in excess in response to low insulin levels and high levels of counterregulatory hormones, the result being the development of metabolic acidosis that is associated with serious health complications. Yet, ketogenic diets have been used for decades to increase ketone body synthesis for their neuroprotective properties as central signalling metabolites and as main energy‐providing substrate for the brain, in epilepsy and neurodegenerative diseases.

Key Concepts

Ketone bodies are key energy substrates and signalling molecules

Ketone bodies participate in energy homeostasis

Diabetic ketoacidosis is the most common pathological cause of elevated blood ketone bodies and is associated with serious health complications

Ketone bodies are neuroprotective

Ketone bodies offer promising perspectives in clinical therapy for certain metabolic diseases, neurodegenerative diseases and cancers
Telomere
Authors: Raffa Grazia D , Cenci Giovanni 
Published: March 2015

Abstract

Telomeres are specialised structures that protect chromosome ends from degradation and fusion events. In most eukaryotes, including yeast and mammals, telomeric DNA consists of short, repetitive G‐rich sequences, which end with 3′ G‐rich overhangs and are elongated by the specialised reverse transcriptase telomerase. Telomeric repeats are bound by several DNA‐binding proteins, which regulate telomerase activity and protect (cap) chromosome ends from degradation and inappropriate DNA repair. If uncapped, telomeres are sensed as DNA breaks and undergo unwanted	DNA repair, which can eventually lead to the activation of cell cycle checkpoints and/or to end‐to‐end fusion. The dicentric chromosomes generated by telomeric fusion can cause non‐disjunction and chromosome breakage during anaphase. These events result in loss of genetic material and chromosome rearrangements that in mammals might lead to several diseases including cancer. Thus, it has become evident that telomeres play critical roles in the maintenance of genome stability.

Key Concepts

Telomeres are required for chromosome end maintenance and genome stability.

Telomeres are special chromatin architectures found at the end of linear chromosomes

Telomeres protects chromosome ends from degradation and fusion events

Telomeric DNA consists of tandem repeats that are bound by several DNA-binding proteins

Critically short telomeres become dysfunctional and eventually lead to chromosome fusions and cell death
DNA
Demethylation
Authors: Wade Paul A 
Published: March 2015

Abstract

Steady‐state levels of deoxyribonucleic acid (DNA) methylation result from a balance of two opposing biological forces: deposition of methyl groups by DNA methyltransferases and their removal by DNA demethylases. The removal of methyl groups from cytosine residues in DNA is an essential biological process that occurs at multiple points during development, differentiation and adult life in both plants and mammals. Demethylation can occur through passive dilution or through active enzymatic processes. Much progress has been made in recent years in the identification of enzymes responsible for active demethylation events. Higher plants have 5‐methylcytosine glycosylases that excise methylated cytosine. Mammals appear to rely on modification of 5‐methylcytosine through deamination or oxidation reactions that predispose the resulting base to repair pathways that result in replacement of 5‐methylcytosine with cytosine. The candidate demethylase enzymes in mammals are subject to translocation and inhibition in cancer, underscoring the biological importance of this process.

Key Concepts

Cytosine methylation is essential for mammalian life; demethylation of 5‐methylcytosine is likely to also be essential.

Demethylation of 5‐methylcytosine could occur through either a passive mechanism involving dilution through rounds of DNA replication or through an active, enzyme‐catalysed process.

Deamination of 5‐methylcytosine by APOBEC family enzymes in the context of DNA results in creation of thymine and a G:T mismatch, a substrate for conventional DNA repair machinery.

TET family enzymes progressively oxidise cytosine residues in DNA to forms that are recognised and excised by well‐characterised DNA glycosylases.

Enzymes identified as candidates in DNA demethylation are frequently mutated or translocated in cancer, suggesting that their precise spatial and temporal regulation is critical to mammalian cells.
Molecular Genetics of Gallbladder Cancer
Authors: Espinoza Jaime A , García Patricia , Bizama Carolina , Roa Juan C 
Published: March 2015

Abstract

Gallbladder cancer (GBC) is a deadly biliary neoplasia with marked ethnic and geographical distribution. The prognosis of GBC is often dismal due to late diagnosis and lack of effective therapeutic options. The main risk factor for GBC is gallstone carriage over long periods of time, which leads to persistent damage and chronic inflammation. This condition promotes genetic/epigenetic alterations and the progressive impairment of the epithelial architecture, mainly through a metaplasia–dysplasia–carcinoma sequence. New molecular alterations have been identified that may help improve the clinical management of patients through the application of more specific therapies. The application of new DNA sequencing technologies is making it possible to catalogue the spectrum of genetic alterations that characterise GBC and is aiding in the understanding of the biology behind gallbladder carcinogenesis. Here, a stepwise model of morphogenetic progression from inflammatory to neoplastic tissues is proposed based on currently available evidence.

Key Concepts

Gallbladder cancer is essentially an inflammatory disease, primarily caused by chronic exposure of the epithelium to gallstones.

Morphological alterations of the epithelium arise mainly through a metaplasia–dysplasia–carcinoma sequence.

Inactivation of tumour suppressor pathway is an early and important carcinogenic event for gallbladder cancer.

Genome‐level alterations such as loss of heterozygosity, microsatellite instability and epigenetic alterations arise early during gallbladder carcinogenesis and increase progressively to advanced stages.

Prevention of chronic inflammation may reduce the onset of early genetic alterations and therefore contribute to reducing gallbladder cancer mortality.

A future challenge is to elucidate molecular subtypes of GBC and identify new potential therapeutic targets in order to improve patient survival.
A Review of Tools, Practices, and Approaches for Sustainable Supply Chain Management
Authors: Reefke Hendrik , Lo Jason 
Published: March 2015

AbstractPurpose—Sustainable supply chain management has become a continuing stream of research with increased interest especially from the year 2005 onwards. The purpose of this article is to conduct a literature review of academic publications on relevant tools, methods, and practices that can be instrumental in the creation of sustainable supply chains.Design/Methodology—A systematic and reproducible literature review was conducted in order to identify, evaluate, and interpret the existing body of knowledge on sustainable supply chain management. The review process comprised material collection, descriptive analysis, categorisation, and interpretation.Findings/Implications—A content analysis of approaches for sustainable supply chain management is presented. The review is structured along categories that relate directly to well‐established key issues in supply chain management. This process provides tangibility to the review insights as they are enfolded against familiar aspects of supply chains. The findings can guide scholars in the field and their understanding thereof.Originality/Value—With the rapid expansion of theoretical contributions and practical developments with regard to sustainable supply chain management, this article offers a needed reference point. It informs researchers of the state of knowledge, guides potential avenues for future research, and may influence practitioners in their selection of approaches that are applicable to their specific requirements.
Radiographic Progression of Patients With Psoriatic Arthritis Who Achieve Minimal Disease Activity in Response to Golimumab Therapy: Results Through 5 Years of a Randomized, Placebo‐Controlled Study
Authors: Kavanaugh Arthur , van der Heijde Désirée , Beutler Anna , Gladman Dafna , Mease Philip , Krueger Gerald G. , McInnes Iain B. , Helliwell Philip , Coates Laura C. , Xu Stephen 
Published: March 2015

ObjectiveTo evaluate long‐term outcomes in psoriatic arthritis (PsA) patients who achieved or did not achieve minimal disease activity (MDA) through 5 years of golimumab treatment in the GO‐REVEAL trial.MethodsThe GO‐REVEAL trial was a phase III, randomized, double‐blind trial with placebo‐control through week 24 followed by an open‐label extension of golimumab 50/100 mg treatment up to 5 years. In these post‐hoc analyses, MDA was defined by the presence of ≥5 of 7 PsA outcome measures (≤1 swollen joint, ≤1 tender joint, Psoriasis Area and Severity Index [PASI] ≤1, patient pain score ≤15, patient global disease activity score ≤20 [range 0–100], Health Assessment Questionnaire disability index [HAQ DI] ≤0.5, and ≤1 tender enthesis point).ResultsTreatment with golimumab yielded significantly higher MDA response rates versus patients randomized to placebo at week 14 (23.5% versus 1.0%; P < 0.0001), week 24 (28.1% versus 7.7%; P < 0.0001), and week 52 (42.4% versus 30.2%; P = 0.037). MDA was achieved at least once by ∼50% of golimumab‐treated patients overall. Irrespective of treatment randomization, achievement of MDA at ≥3 and ≥4 consecutive visits was associated with significantly less radiographic progression and more improvement in MDA components allowing specific assessment of physical function (HAQ DI) and overall disease activity (patient global assessment of disease activity) at week 256 versus patients not achieving MDA. Logistic regression analyses indicated that a 1‐unit higher baseline HAQ DI score yielded a significantly lower likelihood of achieving MDA at ≥3 (odds ratio 0.514 [95% confidence interval 0.321–0.824]; P = 0.006) and ≥4 (odds ratio 0.480 [95% confidence interval 0.290–0.795]; P = 0.004) consecutive visits.ConclusionAmong golimumab‐treated PsA patients, better long‐term functional improvement, patient global assessment, and radiographic outcomes were observed when patients achieved persistent MDA.
Childhood Physical Performance Measures and Adulthood Knee Cartilage Volume and Bone Area: A 25‐Year Cohort Study
Authors: Antony Benny , Jones Graeme , Venn Alison , Cicuttini Flavia , March Lyn , Blizzard Leigh , Dwyer Terence , Cross Marita , Ding Changhai 
Published: March 2015

ObjectiveWe aimed to determine the associations between childhood physical performance measures and tibial cartilage volume and tibial bone area in adults 25 years later.MethodsParticipants (n = 330, ages 31–41 years, female 47%) were selected from the Australian Schools Health and Fitness Survey of 1985. The participants underwent T1‐weighted fat‐suppressed magnetic resonance imaging (MRI) of their knees. Tibial bone area and cartilage volume were measured from MRI. Childhood measures, including physical work capacity at 170 beats per minute (PWC170), leg strength, number of sit‐ups, long‐run, and short‐run were measured in 1985. PWC170 and leg strength measures were repeated after 20 years in their adulthood. Linear regression analysis was used to determine the association of performance measures with cartilage volume.ResultsThere were consistent positive associations of all childhood measures, including PWC170 (β = 0.38 cm2 per 10 watts, 95% confidence interval [95% CI] 0.15, 0.60), leg strength, long‐run, short‐run, and sit‐ups with adult medial and total tibial bone area. Similarly, there was an association of PWC170 and sit‐ups with adult medial tibial cartilage volume. After further adjustment for tibial bone area, the association between PWC170 and medial and total (β = 0.08 cm3 per 10 watts, 95% CI 0.02, 0.10) tibial cartilage volume decreased in magnitude but remained significant.ConclusionChildhood physical performance measures, especially PWC170, were associated with knee tibial bone area and cartilage volume in adulthood. The associations with cartilage volume appeared to be partially mediated by bone area. This suggests physical performance measures in childhood can independently influence adult knee structures.
Magnetic Resonance Imaging–Assessed Vastus Medialis Muscle Fat Content and Risk for Knee Osteoarthritis Progression: Relevance From a Clinical Trial
Authors: Raynauld Jean‐Pierre , Pelletier Jean‐Pierre , Roubille Camille , Dorais Marc , Abram François , Li Wei , Wang Yuanyuan , Fairley Jessica , Cicuttini Flavia M. , Martel‐Pelletier Johanne 
Published: March 2015

ObjectiveStudies have proposed vastus medialis (VM) muscle cross‐sectional area change as a variable associated with cartilage volume loss in knee osteoarthritis (OA). However, the VM also includes fat (%Fat), which may influence knee function. This study analyzed the VM area and %Fat data, separately and in combination, to predict symptoms, cartilage volume loss, and bone marrow lesion (BML) change in knee OA.MethodsThis study included the according‐to‐protocol population (n = 143) of a 2‐year knee OA randomized clinical trial having magnetic resonance imaging at baseline and 2 years. Correlations used multivariate analyses.ResultsGreater baseline value for VM area and %Fat were significantly associated with sex (male, area; female, %Fat), higher body mass index (BMI), and Western Ontario and McMaster Universities Osteoarthritis Index stiffness, function, and total scores (better, high area; worse, high %Fat). Moreover, a VM %Fat increase of 1% at 2 years was associated with worsening of cartilage volume loss in the global knee (P = 0.015) and some subregions (P ≤ 0.030), and with an increment of BML global score change (P < 0.001). A 1% decrease in VM area at 2 years was associated with worsening of knee pain score (P = 0.048). Importantly, the concurrent presence of low VM area, high VM %Fat, and high BMI identified a subgroup of patients with greater cartilage volume loss in the medial femur (P = 0.028) than the rest of the cohort.ConclusionThese data demonstrated, for the first time, that VM fat content is a strong predictor of cartilage volume loss and the occurrence and progression of BML. Importantly, the combined data of VM area, VM %Fat, and BMI identified patients at higher risk for OA progression.