bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inverse sequential simulation: A new approach for the characterization of hydraulic conductivities demonstrated on a non‐Gaussian field
Authors: Xu Teng , Gómez‐Hernández J. Jaime 
Published: March 2015

AbstractInverse sequential simulation (iSS) is a new inverse modeling approach for the characterization of hydraulic conductivity fields based on sequential simulation. It is described and demonstrated in a synthetic aquifer with non‐Gaussian spatial features, and compared against the normal‐score ensemble Kalman filter (NS‐EnKF). The new approach uses the sequential simulation paradigm to generate realizations borrowing from the ensemble Kalman filter the idea of using the experimental nonstationary cross‐covariance between conductivities and piezometric heads computed on an ensemble of realizations. The resulting approach is fully capable of retrieving the non‐Gaussian patterns of the reference field after conditioning on the piezometric heads with results comparable of those obtained by the NS‐EnKF.
A unified approach for process‐based hydrologic modeling: 2. Model implementation and case studies
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. , Gochis David J. , Rasmussen Roy M. , Tarboton David G. , Mahat Vinod , Flerchinger Gerald N. , Marks Danny G. 
Published: March 2015

AbstractThis work advances a unified approach to process‐based hydrologic modeling, which we term the “Structure for Unifying Multiple Modeling Alternatives (SUMMA).” The modeling framework, introduced in the companion paper, uses a general set of conservation equations with flexibility in the choice of process parameterizations (closure relationships) and spatial architecture. This second paper specifies the model equations and their spatial approximations, describes the hydrologic and biophysical process parameterizations currently supported within the framework, and illustrates how the framework can be used in conjunction with multivariate observations to identify model improvements and future research and data needs. The case studies illustrate the use of SUMMA to select among competing modeling approaches based on both observed data and theoretical considerations. Specific examples of preferable modeling approaches include the use of physiological methods to estimate stomatal resistance, careful specification of the shape of the within‐canopy and below‐canopy wind profile, explicitly accounting for dust concentrations within the snowpack, and explicitly representing distributed lateral flow processes. Results also demonstrate that changes in parameter values can make as much or more difference to the model predictions than changes in the process representation. This emphasizes that improvements in model fidelity require a sagacious choice of both process parameterizations and model parameters. In conclusion, we envisage that SUMMA can facilitate ongoing model development efforts, the diagnosis and correction of model structural errors, and improved characterization of model uncertainty.
Ribonucleotide Reduction
Authors: Gleason Florence K 
Published: March 2015

Abstract

Ribonucleotide reductase is an essential enzyme that supplies the deoxyribonucleotides required for DNA synthesis and repair. This one enzyme reduces all four ribonucleotides to the corresponding deoxynucleotides. The enzyme uses a complex radical‐based mechanism to catalyse this reaction. Three main classes of enzymes have been described that differ mainly in the type of cofactor used to generate the catalytic radical. Despite their common reaction mechanism, ribonucleotide reductases show little sequence identity. Crystal structures of enzymes from all classes show a conserved β/α barrel structure in the catalytic domain. Reductase activity is regulated at the protein level by nucleotide allosteric effectors to produce balanced pools of deoxynucleotides. Reductase activity is also coordinated with the cell cycle by activation and repression of gene expression.

Key Concepts

Deoxyribonucleotides required for DNA synthesis and repair are generated only by reduction of ribonucleotides.

One enzyme, ribonucleotide reductase, must reduce all four common ribonucleotides and generate a balanced pool of deoxyribonucleotides to avoid mutations.

Although an essential enzyme in all divisions of life, ribonucleotide reductases diverge widely in primary structure and cofactor requirements.

Ribonucleotide reductase is regulated both at the protein and gene level and can accommodate to environmental changes in the evolution of diverse organisms.

Evolution of ribonucleotide reductases is constrained only by basic catalytic chemistry and protein tertiary structure.
Mitosis: Chromosome Segregation and Stability
Authors: Mustaly Hatim M , Ganem Neil J 
Published: March 2015

AbstractMammalian cells are charged with the task of evenly distributing 46 chromosomes to each of two daughter cells during every mitotic cell division. This is achieved by a microtubule‐based cellular structure termed the mitotic spindle. However, numerous cellular and/or genetic defects are known to impair the fidelity of mitosis and promote chromosome segregation errors and aneuploidy. Missegregation of even a single chromosome leads to the deregulated expression of hundreds to thousands of genes, including many that are involved in essential processes such as DNA replication, repair and mitosis. Consequently, while aneuploidy is most typically detrimental to cell viability, it also has the potential to initiate a self‐propagating cycle of chromosome instability that can ultimately promote tumour initiation, progression and relapse.Key ConceptsChromosome segregation is driven by the mitotic spindle.Multiple genetic and/or cell biological defects are known to cause chromosome missegregation and aneuploidy.Aneuploidy is poorly tolerated in normal cells.Cancer cells adapt to tolerate aneuploidy.Cells that persistently missegregate chromosomes are termed chromosomally unstable (CIN).CIN promotes tumour initiation, progression and relapse and correlates with poor patient prognosis.Aneuploidy and CIN are hallmarks of human tumours.
Genetics of Eye Colour
Authors: Duffy David 
Published: March 2015

Abstract

Human eye colour is a polygenic trait with a heritability of close to 100%, with seven leading factors explaining three‐quarters of the genetic variance:
OCA2
,
TYR
,
TYRP1
,
IRF4
,
SLC45A2
,
SLC24A5
and
SLC24A4
. Many of these genes were already known to be mutated in oculocutaneous albinism, and all are involved in melanin biosynthesis, coding for key enzymes, transcription factors controlling expression of key enzymes or transporters that maintain the acidity of the melanosome interior. At least two of the variants of largest effect abrogate regulatory elements in the associated gene, causing changes in expression level. The differences in eye colour between different populations suggest strong selection, either on correlated traits such as skin colour or perhaps directly.

Key Concepts

Variation in eye colour is polygenic, with seven major genes explaining 75% of European population variance.

Blue eye colour is strongly predicted by a single nucleotide polymorphism near the
OCA2
gene – this is the classical recessive gene inferred from family data. Intermediate eye colours such as hazels and greens are less well predicted.

Two of the major loci are in non‐coding regulatory regions, a pattern common to trait loci for other complex traits.

The large effect sizes make this an excellent model for the investigation of the architecture of gene action, especially gene‐by‐gene interactions (epistasis), as well as multi‐trait action (pleiotropy).

Iris pigmentation loci generally exhibit genomic evidence of strong Darwinian selection, and this may not be completely explained by pleiotropic effects on skin colour.
Effect of a Realigning Brace on Tibiofemoral Contact Stress
Authors: Segal Neil A. , Stockman Tyler J. , Findlay Christian M. , Kern Andrew M. , Ohashi Kenjirou , Anderson Donald D. 
Published: March 2015

ObjectiveTo determine the degree to which focally elevated tibiofemoral joint contact stress is reduced by using a frontal plane realigning brace.MethodsFifteen volunteers (9 women) with unicompartmental tibiofemoral osteoarthritis underwent weight‐bearing radiographic imaging at 15–20° and 5–10° of knee flexion with and without an UnloaderOne knee brace. Discrete element analysis was used to estimate compartment‐specific contact stress distributions. Paired t‐tests were used to assess the differences in mean contact stress and contact stress distributions, comparing the braced and unbraced conditions.ResultsThe mean ± SD age was 56.1 ± 6.4 years and body mass index was 28.4 ± 4.5 kg/m2. Twelve of 15 participants were fit with braces set to unload the medial compartment. For the 15–20° condition, the mean contact stress in the compartment of interest did not significantly change (0.08 ± 0.35 MPa; P = 0.410). Also at 5–10° flexion, the mean contact stress in the compartment of interest did not significantly change with use of the brace (0.24 ± 0.45 MPa; P = 0.175).ConclusionThis is the first study of the effects of a frontal plane realignment brace on in vivo articular contact stress in native human knees. Using the off‐the‐shelf brace tested, there were no changes in compartmental tibiofemoral contact stress distributions at either 15–20° or 5–10° of knee flexion, revealing no redistribution of contact stress away from the compartment of interest. These findings indicate that the brace that was studied was ineffective for redistributing tibiofemoral contact stress. Further research is necessary to determine whether double‐upright or customized frontal plane braces are effective in redistributing compartmental articular contact stress.
Feel the Fatigue and Be Active Anyway: Physical Activity on High‐Fatigue Days Protects Adults With Arthritis From Decrements in Same‐Day Positive Mood
Authors: Hegarty Rosisin S. M. , Conner Tamlin S. , Stebbings Simon , Treharne Gareth J. 
Published: March 2015

ObjectiveThe present study examined whether daily physical activity moderated the within‐person relationship between daily fatigue and positive or negative mood in patients with rheumatoid arthritis (RA) or osteoarthritis (OA).MethodsParticipants were 142 patients, 70 with RA and 72 with OA (67.6% women). Participants completed daily diaries during 4 fixed time windows per day for 7 days. Each diary assessed fatigue, pain, and positive and negative mood. Participants wore pedometers throughout each day and recorded pedometer readings at the end of each day.ResultsPhysical activity buffered the same‐day relationship between daily fatigue and positive mood for both RA and OA participants. On high‐fatigue days, large decrements in mood were noted, but this was mitigated on days when participants were more physically active.ConclusionBeing more physically active on high‐fatigue days buffered the negative effect of fatigue on positive mood among adults with both OA and RA. These findings have implications for understanding the daily variations in fatigue and inform potential clinical interventions.
Sex Differences and Impact of Body Mass Index on the Time Course of Knee Range of Motion, Knee Strength, and Gait Speed After Total Knee Arthroplasty
Authors: Pua Yong‐Hao , Seah Felicia Jie‐Ting , Seet Felicia Jia‐Hui , Tan John Wei‐Ming , Liaw Jennifer Suet‐Ching , Chong Hwei‐Chi 
Published: March 2015

ObjectiveQuadriceps strength deficits and gait speed limitations remain significant issues after total knee arthroplasty (TKA), yet detailed longitudinal data characterizing these measures and their predictors are limited. This study aimed to describe the time course of knee range of motion, quadriceps strength, and gait speed post‐TKA, and to assess whether sex and body mass index (BMI) influenced the time recovery of these measures.MethodsA total of 1,025 patients (mean ± SD age 67 ± 8 years) undergoing primary TKA participated. At 4‐, 8‐, 12‐, and 16‐weeks postsurgery, knee range of motion, quadriceps strength, and gait speed were quantified. The associations of the knee and gait measures profile over time with sex and BMI were assessed using generalized least squares modeling.ResultsThe various knee and gait measures improved nonlinearly over time, with substantial improvements observed in the first 8–10 weeks postsurgery. Sex and BMI influenced the time course of quadriceps strength (P < 0.001 for all interactions): improvements in quadriceps strength over time were slower in women and in patients with higher BMI. Post‐TKA gait speed was consistently lower in women than in men, while BMI was negatively and nonlinearly related to gait speed.ConclusionAlthough the various knee and gait measures improved over time, women and patients with higher BMI had poorer functional outcomes. The present study highlights the need for a mechanistic understanding of the results and targeted management of these patient subgroups.
Diagnosis, Monitoring, and Treatment of Systemic Lupus Erythematosus: A Systematic Review of Clinical Practice Guidelines
Authors: Tunnicliffe David J. , Singh‐Grewal Davinder , Kim Siah , Craig Jonathan C. , Tong Allison 
Published: March 2015

ObjectiveManagement of systemic lupus erythematosus (SLE) is complex and variability in practices exists. Guidelines have been developed to help improve the management of SLE patients, but there has been no formal evaluation of these guidelines. This study aims to compare the scope, quality, and consistency of clinical practice guidelines on the diagnosis, monitoring, and treatment of patients with SLE.MethodsElectronic databases were searched up to April 2014. The Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument and textual synthesis was used to appraise and compare recommendations.ResultsNine clinical practice guidelines and 5 consensus statements were identified, which covered 7 topics: diagnosis, monitoring, treatment, neuropsychiatric SLE, lupus nephritis, antiphospholipid syndrome, and other manifestations of lupus. The methodological quality of the guidelines was variable, with the overall mean AGREE II scores ranging from 31% to 75%, out of a maximum 100%. Scores were consistently low for applicability, with only 1 guideline scoring above 50%. There was substantial variability in the treatments recommended for class II and V lupus nephritis, the recommended duration of maintenance therapy for class III/IV lupus nephritis (from 1 to 4 years), and timing of ophthalmologic examination for patients taking corticosteroids.ConclusionPublished guidelines on SLE cover a complex area of clinical care, but the methodological quality, scope, and recommendations varied substantially. Collaborative and multidisciplinary efforts to develop comprehensive, high‐quality evidence‐based guidelines are needed to promote best treatment and health outcomes for patients with SLE.
Improving the Quality and Productivity of Molded Parts with a New Design of Conformal Cooling Channels for the Injection Molding Process
Authors: Rahim Shayfull Zamree Abd , Sharif S. , Zain Azlan Mohd , Nasir S. M. , Mohd Saad R. 
Published: March 2015

ABSTRACTIn materials processing, quality and productivity are notably important and must be controlled for each product type produced. In the injection molding process, quality is measured as the extent of warpage of molded parts and productivity is measured in terms of the molding cycle time. This paper presents a new design of milled grooved square shape (MGSS) conformal cooling channels, which provide more uniformity in cooling with a larger effective cooling surface area compared to circular and other types of cooling channels with a similar cross‐section. This study examined the warpage of molded parts, and the cooling time, which affected the molding cycle time. A case study involving a front panel housing was performed, and the performance design of the MGSS conformal cooling channels was compared to that of conventional straight‐drilled cooling channels by simulation using Autodesk Moldflow Insight 2013 and validated experimentally. The result of MGSS conformal cooling channels is in a good agreement with the result of simulation. The MGSS conformal cooling channels reduced the warpage in both x and y directions by 14% to 54% and improved the cooling time by 65% compared to straight‐drilled cooling channels.
Characteristics and trends of emergency patients with drug overdose in Osaka
Authors: Kubota Yoshie , Hasegawa Kohei , Taguchi Hirokazu , Kitamura Tetsuhisa , Nishiyama Chika , Iwami Taku , Nishiuchi Tatsuya , Hiraide Atsushi 
Published: March 2015

AimDrug overdose is an important issue in emergency medicine. However, studies covering overdose patients transported by ambulance have not been sufficiently carried out. We attempted to clarify problems of suspected drug overdose patients transported by ambulance.MethodsThis is a prospective population‐based cohort study. Data were collected by emergency medical service crews in Osaka City, Japan, between January 1998 and December 2010.ResultsDrug overdose cases increased annually from 1,136 in 1998 to 1,822 in 2010 (P < 0.0001 for trend). In these cases, the dominant age range was between 16 and 40 years and the age distribution did not change over time. The age of non‐overdose cases increased (P < 0.0001 for trend), with patients aged ≥66 years becoming most common in recent years, reflecting the aging of society. Males comprised most non‐overdose patients, but the percentage of females increased annually (P < 0.0001 in trend). Females comprised approximately 70% in overdose cases annually throughout the study period. The duration from the emergency call to the arrival at the hospital for overdose patients has increased markedly in recent years. It also takes more time to obtain acceptance from hospitals to care for patients of suspected overdose.ConclusionThe characteristics of drug overdose patients are clearly different from those of non‐overdose patients. Recent trends of drug overdose patients indicate the accelerated burden on emergency medical services system.
Nonlinear viscoelastic modeling of soft polymers
Authors: Zacharatos Antonios , Kontou Evagelia 
Published: March 2015

ABSTRACTA one‐dimensional phenomenological constitutive model, representing the nonlinear viscoelastic behavior of polymers is developed in this study. The proposed model is based on a modification of the well‐known three element standard solid model. The linear dashpot is replaced by an Eyring type one, while the nonlinearity is enhanced by a nonlinear, strain dependent spring constant. The new constitutive model was proved to be capable of capturing the main aspects of nonlinear viscoelastic response, namely, monotonic and cyclic loading, creep and stress relaxation, with the same parameter values. Model validation was tested on the experimental results at various modes of deformation for two elastomeric type materials, performed elsewhere. A very good agreement between model simulations and experimental data was obtained in all cases. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42141.
Understanding and tailoring the degradation of PVA‐tyramine hydrogels
Authors: Lim Khoon S. , Roberts Justine J. , Alves Marie‐Helene , Poole‐Warren Laura A. , Martens Penny J. 
Published: March 2015

ABSTRACTWe have previously reported on a hydrogel system fabricated from poly(vinyl alcohol) (PVA) functionalized with tyramine groups (PVA‐Tyr) that has the ability to co‐polymerize with proteins in their native state. These gels were also shown to be hydrolytically degradable through the ester groups present in the functional groups. In this article, the hydrolytic degradation of the PVA‐Tyr gels is shown to be strongly dependant on pH, where at pH < 7.4 the lack of ionization of the tyramine groups resulted in slower hydrolysis. The gels' degradation was also highly influenced by temperature, where heat (>25°C) was required to facilitate the hydrolysis of the ester bonds. Moreover, the degradation rates were successfully tailored between 19 to 27 days by varying the hydrogels' initial macromer concentration. It was highlighted that the cross‐linking density was dependant on the sodium persulphate to tyramine ratio, as well as the viscosity of the macromer solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42142.
Chitosan‐based gel film electrolytes containing ionic liquid and lithium salt for energy storage applications
Authors: Chupp Jeremy , Shellikeri Annadanesh , Palui Goutam , Chatterjee Jhunu 
Published: March 2015

ABSTRACTFabrication, characterization, and a comparative study have been performed for chitosan‐based polymer electrolytes using two different dispersion media. Chitosan gel film (solid) electrolytes are fabricated using acetic acid or adipic acid as the dispersant for chitosan in combination with ionic liquid and lithium salt. This quaternary system of chitosan, acetic acid or adipic acid, 1‐butyl‐3‐methylimadazolium tetrafluoroborate (ionic liquid), and lithium chloride is formed as an electrolyte for potential secondary energy storage applications. The ionic conductivities, thermal, structural, and morphological properties for these electrolytes are compared. The ionic conductivities for chitosan/adipic acid (CHAD) and for chitosan/acetic acid (CHAC) systems are in the range of 3.71 × 10−4−4.6 × 10−3 and 1.3 × 10−4 −3.2 × 10−3 S cm−1, respectively. The thermal stability of CHAD‐based electrolytes is determined to be higher than that of CHAC‐based electrolytes. Preliminary studies are performed to determine the electrochemical stability of these materials as solid film electrolytes for electrochemical supercapacitors. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42143.
Stille cross‐coupling applied to get higher molecular weight polymers: Synthesis, optoelectronic, Voc properties, and solar cell application
Authors: Hanif Muddasir , Chen Linlin , Zhu Li , Zhao Dan , Xiong Tianrou , Hou Haoqing 
Published: March 2015

ABSTRACTConjugated polymers are highly desirable for the photovoltaic applications. We report the synthesis, characterization, optoelectronic properties, and solar cell application of two polymers, namely, poly[(9,9‐didodecylfluorene‐2,7‐diyl)‐alt‐(2,2′:5′,2″‐terthiophene‐5,5″‐diyl)] (P1) and poly[(1,4‐bis(dodecyloxy)benzene‐2,5‐diyl)‐alt‐(2,2′:5′,2″‐terthiophene‐5,5″‐diyl)] (P2). The polymers were synthesized via Stille cross‐coupling reaction, and were characterized by the gel permeation chromatography, nuclear magnetic resonance, Fourier transform infrared, UV–vis, thermogravimetric analysis, and cyclic voltammetry analyses. The two copolymers are processable due to their good solubility in organic solvents (tetrahydrofuran, CHCl3, toluene, chlorobenzene, and o‐dichlorobenzene). The optical band gaps (UV–vis, film, and Egopt) of the P1 and P2 are 2.04 and 2.00 eV, respectively. The density functional theory output structures showed that S…O space interaction is likely responsible for the higher planarity of P2. The polymers showed low HOMO energy levels (P1: −5.33 eV, P2: −5.05 eV). The EHOMO for P1 is close to the EHOMO (−5.4 eV) of an ideal polymer, which is an important, rare, and main origin of the observed higher Voc (801–808 mV). The onset decomposition temperatures (Td) for the P1 and P2 are 418°C and 365°C, respectively. The polymer solar cell based on the P1: C60 (1: 1) and P2: C60 (1: 1) blend showed a power conversion efficiency (PCE) of 0.94 and 0.71%, respectively. The composite polymer : PC60BM = 1 : 2 increased PCE of the P1 (1.65%) and P2 (1.09%) under AM 1.5 illumination (100 mW/cm2). The study provided important examples to design donor–donor (D–D) polymers for the photovoltaic applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42147.