bluuebunny/crossref_metadata_2025_split huggingface dataset:
Immunoassay
Authors: Wu Alan 
Published: May 2017

AbstractImmunoassays are analytical techniques that are widely used to detect and quantitate the concentration of a protein, metabolite, or drug in a biological sample. They are performed in essentially every clinical laboratory in the world today. Results are used by doctors to screen and diagnose diseases, monitor the progress of therapy, and predict those who will develop medical problems in the future. Immunoassays are also the mainstays in research, for example, understanding the pathophysiology of medical disorders in order to develop novel drugs. In order to meet specific testing needs, immunoassays have been developed in a variety of formats. Most of them depend on the unique features of the reaction between an antigen and its complementary antibody to achieve specificity for the analyte of interest. However, other antigen‐binding materials are increasingly being used.Key ConceptsAntibodies are raised in non‐human species targeted to specific epitope of the intended target (antigen).Some assays are subjected to interferences due to the presence of unusual antibodies in the sample (heterophile and human anti‐animal antibodies).The use of chimeric and humanised antibodies improves the performance of immunoassays over those antibodies that are 100% animal.Heterogeneous immunoassays require a physical separation between antibody‐bound and free analytes.Homogeneous immunoassays do not require a physical separation step.Antigens present in excess concentrations can produce falsely low results in both immunoprecipitation (prozone) and immunometric (hook effect) assays.Point‐of‐care devices make use of immunochromatographic assays.There are a variety of detectors used in immunoassays such as enzymes, fluorophores, luminescent tags, electrochemical reactions and immunosensors.Multiplexing immunoassays can be accomplished through microbead or microchip arrays.
Allele Spectrum of Human Genetic Disease
Authors: Weiss Kenneth M 
Published: May 2017

Abstract

The allelic spectrum of a disease refers to the number of places in the genome in which DNA sequence variation affects a specified disease, and the relative frequencies of these individual alleles in a population or sample. Most variants will be relatively rare compared with other alleles at their respective location and most typically will have individually weak effects on the risk of the disease. Because variation arises locally by mutation, and spreads only slowly, and because most variants are due to recent mutation, the predominant part of the spectrum consists of many rare variants. However, for all but the simplest of diseases, the effect of a variant, and hence its presence in the disease's allelic spectrum, is dependent on the individual genomic and environmental contexts in which it is found.

Key Concepts

Mutation and recombination produce variation.

The amount of variation varies over time and among populations.

Allelic variation contributing to disease is often spread across many sites within a gene or many genes.

The frequency of most variants is small, as are their typical effects.

The effects of an allele typically depend on its genomic and environmental context in the individual.
Pattern Recognition Receptors
Authors: Childs KS , Goodbourn S 
Published: May 2017

Abstract

Multicellular organisms continually come into contact with microbes in the environment, and protecting themselves from infection is vital to their survival. The innate immune system has a critically important role in acting as a first line of defence against this threat, by rapidly detecting and destroying any foreign invaders. Recognition of pathogens by the innate immune system is achieved through the actions of a large collection of pattern recognition receptors that bind to unique features of pathogens called pathogen‐associated molecular patterns that are not normally found in the host. Recognition is followed by the production of cytokines and chemokines and activation of innate immune responses that restrict, destroy and dispose of the pathogen and promote the subsequent activation of an adaptive immune response.

Key Concepts

Pattern recognition receptors (PRRs) detect foreign molecules associated with pathogens, termed pathogen‐associated molecular patterns (PAMPs).

PAMPs are specific to groups of pathogens and are not normally found in the host.

PRRs are found in different tissues and in different subcellular compartments according to the types of pathogen that they recognise.

Activation of PRRs leads to innate immune responses that destroy the pathogen.
D
arwinian Evolution of Tumours
Authors: He Xionglei , Chen Han 
Published: May 2017

Abstract

Tumours as a human disease have been studied mostly from a mechanistic perspective in the past decades. It is now increasingly clear that tumourigenesis as an evolving process can be fully understood only in the light of evolution. Recent studies highlight the necessity of connecting the microevolution of a tumour with the macroevolution from unicellular life to metazoan multicellularity, which occurred ∼600 million years ago. With this background in mind, we discuss here the diverse, sometimes conflicting, views with regard to the driving forces of tumour evolution. Specifically, we show how mutation, selection, drift, migration, gain of function versus loss of function, genetic factors versus non‐genetic factors and deterministic forces versus stochasticity may affect the trajectory of a tumour evolution as well as our understanding.

Key Concepts

Tumourigenesis is a by‐product of the macroevolutionary event from unicellular life to metazoan multicellularity that occurred ∼600 million years ago.

Tumour progression is a microevolutionary process of the asexual tumour cell population, driven in part by forces typical to organismal evolution.

Unlike long‐term organismal evolution, which is driven exclusively by genetic forces, the short‐term tumour evolution can be affected heavily by epigenetic alterations. As a result, the decoupling between genetic divergence and expression divergence is expected.

Tumour evolution represents a reversal of the macroevolution from unicellularity to multicellularity, by erasing the constraints evolved for the maintenance of multicellularity. As a result, loss of function plays a more important role than gain of function.

Regardless of the external tissue environments, nearly all tumours evolve towards a predetermined cellular destination with properties typical to unicellular life.

Tumour evolution is driven by both deterministic factors and stochastic factors. Recognition of this helps reconcile development and evolution, two distinct languages in the cancer research community, with the former spoken mostly by cell biologists who advocate fixed cellular programmes as driving forces and the latter spoken by geneticists who appreciate the apparent stochasticity of driver gene mutations.
Health Assessment of Children Being Adopted: Practice, Challenges and Dilemmas
Authors: Sampeys Carolyn , Barnes Peter 
Published: May 2017

Abstract

The medical adviser in adoption is a statutory role, usually undertaken by an experienced community paediatrician. A key task of the medical adviser is the provision of a comprehensive preadoption health report on a child for whom the local authority plan is adoption. The vast majority of children being placed for adoption come from the care system and are likely to have adverse childhood experiences. The medical adviser collates information about the birth family health history, the child's prenatal and birth information, early development and health, alongside early life experiences and advises on the relevance of this information. Close working links between the medical adviser in adoption and other key professionals are important in order to achieve the best outcomes for this special group of children, including the provision of post‐adoption support. Dilemmas and challenges are commonly encountered by those who undertake this role.

Key Concepts

The medical adviser in adoption has a key role in collating all available health information and sharing this with the adoption agency and prospective adoptive parents.

A quality preadoption health assessment and report are essential for matching a child with prospective adoptive parents.

A preadoption health report should include information about the health of the child's birth family, the child's birth and identified antenatal factors, early health and development and life experiences with guidance provided around the potential future implications of these factors.

Adoption is a lifelong journey and new/additional health information in the birth family may come to light at any point. Mechanisms are required to ensure that this is shared and discussed appropriately.

Close working relationships between the medical adviser in adoption and adoption agency staff/local authority social workers are crucial.

Dilemmas and challenges are commonly encountered by those who undertake this role.

The needs of the child are paramount in the process of adoption.
Legume Nitrogen Fixation and Soil Abiotic Stress: From Physiology to Genomics and Beyond
Authors: Valentine Alex J. , Benedito Vagner A. , Kang Yun 
Published: May 2017

AbstractLegumes are important components of the nitrogen cycle on land. Agricultural systems have traditionally relied much on legumes for nitrogen input because many species are able to establish symbioses with diazotrophic bacteria (rhizobia) and thus trade metabolites and reduced compounds. Photosynthates produced in the leaves are allocated to the root nodule to supply the bacteroids with carbon, in exchange for reduced nitrogen (ammonia) produced by the rhizobia from atmospheric nitrogen. Despite its major significance to plant breeding and sustainable agriculture, the impact of abiotic stresses on nodule development and stability and on symbiotic nitrogen fixation remains poorly understood, particularly at the molecular level. However, the study of model legume species and the development of a plethora of resources, particularly the elucidation of the genome sequences of three legume species, are now revealing many traits of agricultural importance in legumes as well as other aspects that are not easily studied in other plant models, such asArabidopsisor rice. In this chapter, we will discuss the effects of abiotic stresses, such as drought, phosphate deficiency and aluminium toxicity, on symbiotic nitrogen fixation and provide perspectives on molecular approaches to the analysis of stress responses in legumes.
Mitochondrial Redox State, Nitrogen Metabolism and Signalling
Authors: Foyer Christine H. 
Published: May 2017

AbstractNitrogen is often a limiting factor for plant growth and development, and therefore there is considerable interest and potential agronomic benefit not only in understanding the mechanisms that determine nitrogen use efficiency (NUE) but also in identifying new targets for NUE improvement. Much attention in recent years has focused on the core pathways and enzymes involved in primary nitrogen assimilation as well as the processes of N uptake and transport. However, recent studies on mitochondrial Complex I mutants indicate that enzymes involved in energy metabolism in the mitochondria could also be useful targets for improving NUE. TheNicotiana sylvestriscytoplasmic male sterile II (CMSII) mutant lacks respiratory Complex I, but high rates of respiration are sustained because of the presence of alternative NADH dehydrogenases. The CMSII mutation has striking effects on leaf amino acids, which are the focal point around which primary N assimilation and associated carbon metabolism and photorespiration and export occur, and on pyridine nucleotides, which are essential for metabolism and signalling. The absence of major mitochondrial NADH dehydrogenase (Complex I) in the CMSII mutant results in an N‐rich phenotype and altered N signalling. Adjustments in the abundance of Complex I relative to the alternative NADH dehydrogenases could therefore provide a mechanism for improved NUE.
Adaptive dynamic programming for tracking design of uncertain nonlinear systems with disturbances and input constraints
Authors: Cui Xiaohong , Zhang Huaguang , Luo Yanhong , Jiang He 
Published: May 2017

SummaryIn this paper, the
tracking controller is designed for uncertain nonlinear systems with external disturbances and input constraints. A discounted nonquadratic function is introduced, which encodes the constrained input into the
performance. The key difficulty for
tracking control is the requirement of solving the tracking Hamilton‐Jacobi‐Isaacs equation, which is a partial differential equation. It is impossible or extremely difficult to solve analytically even in simple cases. To overcome the difficulty, an online model‐free integral reinforcement learning (IRL) algorithm is proposed to learn online in real time the solution to the tracking Hamilton‐Jacobi‐Isaacs equation without requiring any knowledge of system dynamics. To implement it, critic‐actor‐disturbance neural networks (NNs) are built, and the 3 NNs are updated simultaneously. Stability and convergence analyses are shown by the Lyapunov method. In addition, a robust term is added to the controller to attenuate the effect of NN approximation errors, which leads to the asymptotic stability of the closed‐loop systems. Finally, 2 simulation examples show the effectiveness of the proposed algorithm.
Acyl Radical Addition onto Aza‐Baylis–Hillman Adducts: A Stereocontrolled Access to 2,3,5‐Trisubstituted Pyrrolidines
Authors: Grélaud Simon , Lusseau Jonathan , Massip Stéphane , Landais Yannick 
Published: May 2017

AbstractFree‐radical addition of acyl radicals to chiral aza‐Baylis–Hillman adducts was shown to afford the corresponding 1,4‐amino ketones in good yields and good 1,2‐stereocontrol. These ketones were then elaborated further using conditions varying as a function of the nature of the N‐protecting group. Robust N–Ts protection thus allowed the formation, under acidic conditions, of a cyclic iminium which was reduced using bulky (Me3Si)3SiH into the corresponding 2,3,5‐pyrrolidine exhibiting a trans‐trans relative configuration. In contrast, under these conditions, the N‐Boc protecting group was removed, leading to the formation of stable dihydropyrroles, which were then hydrogenated with PtO2, leading to 2,3,5‐pyrrolidines having a trans‐cis relative configuration. When additional ketone or ester groups were present on the pyrrolidine skeleton, further cyclization led to indolizidinones and pyrrolizidines in good overall yield in 4 steps and two‐pot operations.magnified image
Associations between safety climate and safety management practices in the construction industry
Authors: Marín Luz S. , Lipscomb Hester , Cifuentes Manuel , Punnett Laura 
Published: May 2017

BackgroundSafety climate, a group‐level measure of workers’ perceptions regarding management's safety priorities, has been suggested as a key predictor of safety outcomes. However, its relationship with actual injury rates is inconsistent. We posit that safety climate may instead be a parallel outcome of workplace safety practices, rather than a determinant of workers’ safety behaviors or outcomes.MethodsUsing a sample of 25 commercial construction companies in Colombia, selected by injury rate stratum (high, medium, low), we examined the relationship between workers’ safety climate perceptions and safety management practices (SMPs) reported by safety officers.ResultsWorkers’ perceptions of safety climate were independent of their own company's implementation of SMPs, as measured here, and its injury rates. However, injury rates were negatively related to the implementation of SMPs.ConclusionsSafety management practices may be more important than workers’ perceptions of safety climate as direct predictors of injury rates.
A Highly Stereoselective Synthesis of Tetrahydrofurans
Authors: Appun Johannes , Boomhoff Michael , Hoffmeyer Patrick , Kallweit Isa , Pahl Maik , Belder Detlev , Schneider Christoph 
Published: May 2017

AbstractThe development of a direct and highly stereoselective synthesis of 2,3,5‐substituted tetrahydrofurans has been accomplished through a combination of batch‐ and microchip‐MS‐experiments. This sequential transformation comprises a Lewis acid‐mediated reaction of bis(silyl) dienediolate 1 and a broad range of aldehydes, furnishing products with three new σ‐bonds and three stereogenic centers in a one‐pot process with typically good yields and excellent stereoselectivity. Key steps which have been elucidated primarily with microchip‐MS‐experiments include a vinylogous aldol reaction and a Prins‐type cyclization. Furthermore, a titanium BINOL complex is a powerful chiral catalyst for this process. The products were further converted into bi‐ and tricylic products by carbonyl–ene reactions, proceeding with excellent yields and diastereoselectivity.
Reversible Stabilization of Vesicles: Redox‐Responsive Polymer Nanocontainers for Intracellular Delivery
Authors: de Vries Wilke C. , Grill David , Tesch Matthias , Ricker Andrea , Nüsse Harald , Klingauf Jürgen , Studer Armido , Gerke Volker , Ravoo Bart Jan 
Published: May 2017

AbstractWe present the self‐assembly of redox‐responsive polymer nanocontainers comprising a cyclodextrin vesicle core and a thin reductively cleavable polymer shell anchored via host–guest recognition on the vesicle surface. The nanocontainers are of uniform size, show high stability, and selectively respond to a mild reductive trigger as revealed by dynamic light scattering, transmission electron microscopy, atomic force microscopy, a quantitative thiol assay, and fluorescence spectroscopy. Live cell imaging experiments demonstrate a specific redox‐responsive release and cytoplasmic delivery of encapsulated hydrophilic payloads, such as the pH‐probe pyranine, and the fungal toxin phalloidin. Our results show the high potential of these stimulus‐responsive nanocontainers for cell biological applications requiring a controlled delivery.
Chemically Controlled Spatiotemporal Oscillations of Colloidal Assemblies
Authors: Altemose Alicia , Sánchez‐Farrán María Antonieta , Duan Wentao , Schulz Steve , Borhan Ali , Crespi Vincent H. , Sen Ayusman 
Published: May 2017

AbstractWe report an autonomous oscillatory micromotor system in which active colloidal particles form clusters, the size of which changes periodically. The system consists of an aqueous suspension of silver orthophosphate microparticles under UV illumination, in the presence of varying concentrations of hydrogen peroxide. The colloid particles first attract each other to form clusters. After a short delay, these clusters abruptly disperse and oscillation begins, alternating between clustering and dispersion of particles. After a cluster oscillation initiates, the oscillatory wave propagates to nearby clusters and eventually all the clusters oscillate in phase‐shifted synchrony. The oscillatory behavior is governed by an electrolytic self‐diffusiophoretic mechanism which involves alternating electric fields generated by the competing reduction and oxidation of silver. The oscillation frequency is tuned by changing the concentration of hydrogen peroxide. The addition of inert silica particles to the system results in hierarchical sorting and packing of clusters. Densely packed Ag3PO4 particles form a non‐oscillating core with an oscillating shell composed largely of silica microparticles.
Substituent Effects in Parallel‐Displaced π–π Stacking Interactions: Distance Matters
Authors: Riwar Leslie‐Joana , Trapp Nils , Kuhn Bernd , Diederich François 
Published: May 2017

AbstractHost–guest systems with Rebek imide type receptors and a 2,6‐di(isobutyramido)pyridine ligand were employed to investigate substituent effects in parallel‐displaced π–π stacking interactions. Changing the intermolecular distance between the para substituent on the aromatic platform of the receptor and the pyridine ring of the guest results in a strongly different substituent effect. With a short ethyne‐1,2‐diyl spacer between the Rebek imide and the aromatic platform, partial overlap of substituent and guest stabilizes the π–π stacking interactions independent of the electronic nature of the substituent (Wheeler–Houk model). When the substituent is shifted further away by using a buta‐1,3‐diyne‐1,4‐diyl spacer, direct, through‐space interactions between substituent and guest are prevented. A linear correlation between logKa (Ka=association constant) and the Hammett substituent constant σpara is observed, confirming predictions by the Hunter–Sanders model experimentally.
Evaluation on H2O2‐aided ultrasonic pretreatment for cell disruption of Chlorella pyrenoidosa
Authors: Duan Zhipeng , Tan Xiao , Dai Kaiwen , Gu Huihui , Yang Hanpei 
Published: May 2017

AbstractIn this work, Chlorella pyrenoidosa was chosen as model microalgae, and several pretreatments, including hydroxyl‐peroxide‐aided ultrasonic pretreatments and mono‐ultrasonication (US), were used to rupture the microalgal cells for extracting cellular inclusion. The disruption efficiency and the energy consumption of each technique were estimated through measuring the amount of released protein from cells and the microscopic images after pretreatment. Results showed that the combined pretreatments obtained a much higher lysis efficiency than did the US (over twofold). However, the concentration of H2O2 used (ranging from 0.1 to 5 mM) failed to influence the lysis efficiency significantly (P < 0.05). Additionally, the acoustic energy efficiency was increased with the initial cell concentration treated, but the coefficient of utilization of algal biomass was decreased significantly. Therefore, an ideal initial cell concentration (13.4 × 107 cells/mL) was gained in terms of the higher coefficient of utilization of algal biomass. This research suggested that a synergistic technique could be an effective pretreatment for microalgal cell disruption and downstream comprehensive utilization. © 2017 Curtin University of Technology and John Wiley & Sons, Ltd.
Hydrophobic associated copolymer as a wide temperature range synthetic cement retarder and its effect on cement hydration
Authors: Xia Xiujian , Guo Jintang , Chen Di , Feng Yakai , Yu Yongjin , Jin Jianzhou , Liu Shuoqiong 
Published: May 2017

ABSTRACTHexadecyldimethylpropylmethacrylamide ammonium bromide was well prepared, allowed to copolymerize with other functional monomers to develop a hydrophobic associated polymer (PIADH) as a wide temperature range cement retarder. The synthetic copolymer was testified by Fourier transform infrared spectroscopy,1H‐nuclear magnetic resonance, thermo gravimetric analysis, and differential scanning calorimetry. Its temperature induced adaptability was verified via fluorescence probe and NaOH titration techniques, indicating that the retarding groups were increasing at elevated temperature. The applied performance of PIADH modified cement slurries was also evaluated. The results manifested that PIADH not only had excellent retarding property, but also was insensitive to its concentration and temperature variations. Meanwhile, it exhibited less impact on the compressive strength of set cement in large temperature difference. Besides, the inclusion of PIADH improved the microstructure of hardened cement, which was conducive to its mechanical property. The effect of PIADH on cement hydration was also investigated by the isothermal heat flow calorimetry and X‐ray diffraction, showing that the retardation of PIADH was achieved through prolonging the induction period and inhibiting the nucleation of portlandite and ettringite crystals. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2017,134, 45242.