bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ornithine Transcarbamylase Deficiency: Genetics
Authors: Azevedo Luisa , Oliveira Ana Sofia , Amorim Antonio 
Published: August 2017

Abstract

Ornithine transcarbamylase deficiency, the most common urea cycle disorder, is an X‐linked trait displaying large heterogeneity, including cases of symptomatic heterozygotes and very mild hemizygous individuals. A wide mutational spectrum, comprising more than 500 disease‐associated mutations, is currently known. More than two‐thirds of the mutations are nucleotide replacements at the coding region of the gene.
De novo
mutations are common being responsible for as much as three‐fourths of female abnormal chromosomes. Recurrent mutations found in different human populations are associated with hypermutable CpG dinucleotides, and these features render diagnosis and genetic counselling, particularly challenging. The responsible gene is, however, an excellent model for research on human mutation, owing to (1) the mode of transmission (allowing direct haplotype ascertainment and evaluation of the role of recombination) and (2) the abundance and diversity of mutations. Treatment strategies involve reduction of protein level intake and stimulation of alternative metabolic pathways or liver transplantation.

Key Concepts

OTC is a urea cycle enzyme mainly expressed in the liver.

OTC deficiency is an X‐linked disease that presents a heterogeneous phenotypic severity.

The mode of inheritance renders the phenotypic severity to be more evident in males.

The genotype–phenotype relationship is not straightforward.

Epistatic interactions have been detected in the OTC protein.
Metabolite Profiling in Plants
Authors: Osorio Sonia , Vallarino José G 
Published: August 2017

Abstract

Advances in analytical chemistry, computation and biotechnology have led to the recent development of methodologies for broad metabolite profiling. Metabolomics now plays a significant role in fundamental plant biology and applied biotechnology. The study of plant metabolism has been one of the first beneficiaries of these technologies, and applications have focused on plant metabolite engineering, functional genomics and physiology. Metabolomics has gained importance in biotechnology applications, as exemplified by quantitative loci analysis. Integration of different broad‐range metabolite profiling into genomics approaches (system biology) driven by metabolome data will bring a change in our understanding of the regulation of metabolic networks and, therefore, facilitate improvements in our understanding of plant breeding.

Key Concepts

Metabolomics is defined as the quantitative complement of low‐molecular‐weight metabolites present in a cell under a given set of physiological conditions.

Systems biology is the combination of molecular and system‐level studies applying a synergistic approach involving modelling, theory and experiment.

Metabolite marker is a metabolite that is objectively measured and evaluated as an indicator of normal biological processes or specific trait.

Metabolic phenotype is the products of interactions among a variety of factors such as environment or genetic perturbation.

Functional genomics is the field of molecular biology that uses many possible approaches (i.e. genomics, transcriptomics, proteomics and metabolomics) to understand the properties and function of the entirety of an organism's genes and gene products.
Molecular Genetics of Addictions
Authors: Yang Zhongli , Li Ming D 
Published: August 2017

Abstract

Addictions to both licit and illicit drugs are common chronic brain disorders that are extremely costly to the individuals and society. Although genetics contributes significantly to vulnerability to these affective disorders, the susceptibility genes underlying them are largely unknown. Various genetics approaches including genome‐wide linkage, candidate gene association, GWAS and sequencing analysis have implicated several common genomic regions and genes in the aetiology of addiction to multiple substances. For example, variants in the α2 subunit of GABA
A
receptor have been found repeatedly in association with alcoholism and alcohol‐related phenotypes. A gene cluster on chromosomes 15q24/q25.1 that encompasses the genes for nicotine acetylcholine receptor subunits α5, α3 and β4 was implicated in addiction to tobacco and other substances as well. Current efforts aim not only to replicate these findings in independent samples but also to determine the functional mechanisms of these associations.

Key Concepts

Drug addiction is a chronic brain disorder.

Both human and animal studies reveal that addiction is determined not only by genetic and environmental factors but also by their interactions.

There exist significant genetic overlaps among addictions to different substances.

It is important to determine not only genetic but also environmental factors involved in the aetiology of addictions.

Various genomic regions have been revealed to harbour susceptibility loci for multiple addictive disorders.

Genes such as those encoding GABA‐A and GABA‐B receptor subunits, neurexins 1 and 2 and some nicotinic receptor subunits are revealed to be associated with addictions.

Determination of gene–environmental interactions is as important and challenging as determining gene–gene interactions.

Small microRNAs may play important roles in the mediation of expression of genes implicated in addictions.
G
Proteins
Authors: Willardson Barry M , Tensmeyer Nicole C 
Published: August 2017

Abstract

Cells respond to many hormones, neurotransmitters, bioactive peptides and sensory molecules through G protein signalling. The process begins with the binding of the signalling molecule to the extracellular face of a G‐protein‐coupled receptor (GPCR) that initiates binding of the G protein heterotrimer on the intracellular side of the receptor. This interaction causes exchange of GDP for GTP on the G protein α subunit, triggering a conformational change that dissociates the Gα‐GTP from Gβγ. These G protein subcomplexes then interact with effector enzymes and ion channels and elicit a cellular response to the signal. GPCRs constitute the largest class of transmembrane receptors, with 800 genes in the human genome. Consequently, G protein signalling contributes to almost all aspects of human physiology, and GPCRs are the single most common class of drug targets.

Key Concepts

G protein signalling contributes to almost all aspects of human physiology, including sensory perception, neuronal transmission and hormone secretion.

Agonist binding to a G‐protein‐coupled receptor initiates an interaction with the G protein heterotrimer that triggers nucleotide exchange on the G protein α subunit (Gα).

The binding of GTP to Gα causes its dissociation from the receptor and the G protein βγ dimer (Gβγ), allowing Gα‐GTP and Gβγ to interact with effector enzymes and ion channels.

Effector enzymes and ion channels change the concentration of second messenger molecules or the membrane potential to elicit the cellular response to the agonist.

The rate of GTP hydrolysis by Gα, which determines the duration of the G protein signal, is controlled by GTPase‐accelerating proteins called regulators of G protein signalling.

To function, the G protein heterotrimer must be assembled from its individual subunits by molecular chaperones.
Molecular Genetics of Isolated Acromesomelic Dysplasia
Authors: Khan Saad U , Khan Sher A , Muhammad Noor 
Published: August 2017

Abstract

Acromesomelic dysplasia is a type of skeletal malformation affecting distal and middle segments of the extremities. Both isolated (nonsyndromic) and syndromic forms have been reported. In syndromic forms, it shows association with respiratory, cardiac, neurological and genital abnormalities. Acromesomelic dysplasia segregates in autosomal recessive mode of inheritance. Three genes (
GDF5
,
NPR2
and
BMPR1B
) have been reported to cause different forms of acromesomelic dysplasia.

Key Concepts

In case of AMDM, the short stature found in heterozygous carriers is probably caused by a codominant effect of the mutant allele.

Natriuretic peptides are hormones, involved in the regulation of various physiological processes.

Mutations in the
NPR2
gene results in loss of functions and consequently affect the skeletal growth and is responsible for AMDM.

Mutations in GC‐binding domain in the gene
Npr2
result in impaired endochondral ossification and severe dwarfism in mice.

The GDF5 is a ligand of BMP receptors, its absence results in abnormal joint formation and ligament defects.

AMDH patients are homozygous for a 22‐bp tandem duplication frameshift mutation in the mature region of CDMP‐1.

Du Pan dysplasia is caused by biallelic loss‐of‐function mutations in
GDF5
gene.

Acrosomelic dysplasia Demirhan Type (AMDD) is caused by homozygous mutation in
BMPR1B
gene.

BMPR1B is the major receptor for GDF5, a signalling molecule of the BMP family that plays a major role in digit formation, joint development and chondrocyte differentiation.

Sheep with
BMPR1B
or
BMP15
missense mutations do not exhibit a skeletal phenotype.

The skeletal and genital phenotype of the BmpR1b
−/−
mouse is similar to the clinical anomalies associated with the human BMPR1B mutation.
Glia Signalling during Neurological Damage and Disease
Authors: Yong Yu , Heckle Lindsay A , Arena Kimberly A , Goertz Jennifer E , Kucenas Sarah , Deppmann Christopher D 
Published: August 2017

Abstract

While glia were once thought to be nothing more than glue‐like cells that hold the nervous system together, there is growing evidence that signals to and from glia are indispensable for development, cell‐to‐cell communication and maintenance of efficient nervous system function. Several studies show that glia often receive conflicting signals during disease progression and can play dual roles as both antagonists and neuroprotectors in distinct settings.

Key Concepts

Glia play neuroprotective and neurodegenerative role during the initiation and progression stage of neurodegenerative diseases.

Astrocytes mediate calcium‐related neurotoxicity in Alzheimer's disease.

Microglia regulate neurodegeneration in Parkinson's disease through NO‐related apoptotic pathway.

Oligodendrocytes and Schwann cells regulate myelin wasting diseases in central and peripheral nervous system through Wnt and ErbB2/ErbB3 signalling pathways.

Glial cells form a scar following spinal cord injury that affects regenerative abilities.
Controllable Virus‐Directed Synthesis of Nanostructured Hybrids Induced by Organic/Inorganic Interactions
Authors: Atanasova Petia , Kim Insook , Chen Bingling , Eiben Sabine , Bill Joachim 
Published: August 2017

AbstractThe bioinspired synthesis of hierarchical hybrid nanomaterials using biological objects as a template attracts growing interest for the design of new technologically relevant nanostructured materials. To ensure control over the shape and properties of the fabricated hybrid structures, understanding of the growth mechanism is required. In this work, tobacco mosaic virus (TMV) is used as a template to direct the synthesis of zinc sulfide (ZnS) at ambient conditions and different pH from additive‐free aqueous solution. TMV/ZnS hybrid nanowires or thin films are obtained with controllable thickness of the inorganic layer. The deposition mechanism is studied by monitoring the optical properties, band gap (Eg) and particle size, respectively, of ZnS particles mineralized on the TMV template and ZnS reference nanoparticles. A heterogeneous nucleation of the inorganic phase on the template surface is proposed. Band gap measurements reveal that the average size of the ZnS nanoparticles grown on the virus surface is smaller compared to solution‐grown nanoparticles. Moreover, a blue shift of the ZnS photoluminescence peak indicates a dominance of different crystal lattice defects in both systems. The present method for the selective template‐directed mineralization opens new possibilities in the synthesis of well‐organized functional hybrid materials.
Copper‐Catalyzed Decarboxylative Alkylation of Terminal Alkynes
Authors: Ye Changqing , Li Yajun , Bao Hongli 
Published: August 2017

AbstractA copper‐catalyzed decarboxylative alkylation of terminal alkynes under mild reaction conditions has been reported. Various alkyl diacyl peroxides were applied as the alkyl source for the formation of C(sp3)−C(sp) bond. A range of terminal alkynes including aryl alkynes and alkyl alkynes delivered the alkylated internal alkynes with good to high performances. Mechanism studies suggested that this reaction involves a free radical pathway.magnified image
A Switchable Interconnecting Layer for High Performance Tandem Organic Solar Cell
Authors: Lu Shunmian , Lin Hong , Zhang Shaoqing , Hou Jianhui , Choy Wallace C. H. 
Published: August 2017

AbstractThe all‐solution‐processed switchable interconnecting layer (ICL) for both inverted and normal tandem organic solar cells (OSCs) is reported for the first time here. The fundamental challenges in the literature arise from mixing multiple functionalities into a single layer. For a widely used ICL composed of an electron transport layer (ETL)/a hole transport layer (HTL), ETL needs not only to efficiently extract electrons from an underneath photoactive layer, but also to fulfill optical, mechanical, chemical and electrical requirements to function as effective tunneling junction ICL with HTL atop. Taking on multiple functionalities for a single ETL makes ETL in ICL highly coupled and difficult to be replaced. This is also the case for HTL. Here, this study demonstrates an all‐solution‐processed switchable ICL, ETL/recombination layer (RL)/HTL and HTL/RL/ETL, for both normal and inverted tandem OSCs. In switchable ICL, ETL and HTL simply serve as carrier transport layers as they did in single OSCs. Electrical recombination, mechanical protection and chemical separation functionalities are realized by RL alone. This strategy shifts the views of ICL for tandem OSCs from conventionally complicated ETL/HTL tunneling junction ICL, where both ETL and HTL play several different roles, towards simplified ICL where ETL and HTL play a distinct decoupled role, advancing ICL for more adaptable tandem OSCs.
Ein ikosidodekaedrisches Supramolekül auf Basis von Pentaphosphaferrocen: von einer fehlgeordneten gemittelten Struktur zu einzelnen Isomeren
Authors: Heindl Claudia , Peresypkina Eugenia , Virovets Alexander V. , Bushmarinov Ivan S. , Medvedev Michael G. , Krämer Barbara , Dittrich Birger , Scheer Manfred 
Published: August 2017

AbstractDie Pentaphosphaferrocene [CpRFe(η5‐P5)] (1) und CuI‐Halogenide sind exzellente Bausteine für die Bildung diskreter Supramoleküle. Hier wird das Potenzial von Cu(CF3SO3) für die Herstellung des neuartigen 2D‐Polymers [{Cp*Fe(μ4,η5:1:1:1‐P5)}{Cu(CF3SO3)}]n (2) und eines einzigartigen Nanoballs (CH2Cl2)1.4@[{CpBnFe(η5‐P5)}12{Cu(CF3SO3)}19.6] (3) gezeigt. Das Supramolekül 3 hat ein außergewöhnliches Gerüst jenseits der Fulleren‐Topologie, das aus 20 Cu‐Atomen besteht, die statistisch auf 30 Eckpunkte eines Ikosidodekaeders verteilt sind. Erstmals wurde die Kombinatorik zur Interpretation einer gemittelten fehlgeordneten Struktur von Supramolekülen genutzt. Dabei zeigte sich, dass für die zweizähnige verbrückende Koordination von Triflatliganden im Gerüst nur zwei Paare enantiomerer Formen mit D5‐ und D2‐Symmetrie möglich sind. DFT‐Rechnungen zeigen, dass die Energieunterschiede der Isomere vernachlässigt werden können. Die Benzyl‐Liganden von 3 ermöglichen NMR‐spektroskopische und MS‐Untersuchungen.
Ein Weg zu gemischten Pnictogenylboranen
Authors: Hegen Oliver , Marquardt Christian , Timoshkin Alexey Y. , Scheer Manfred 
Published: August 2017

AbstractWir berichten über die Synthese und Charakterisierung von gemischten Pnictogenylboranen. Die Substitution der Lewis‐Base SMe2 in (OC)5W‐PH2BH2‐SMe2 (2) durch verschiedene Pnictogenylborane ER2BH2‐LB (E=P, As, Sb) führt zu den Lewis‐Säure/Base‐stabilisierten, Butan‐analogen Molekülen (OC)5W‐PH2BH2ER2BH2‐LB (3 a,b: E=P, R=H, SiMe3, LB=NMe3; 4 a,b: As, R=H, SiMe3, LB=NMe3; 5: Sb, R=SiMe3, LB=NHCMe). Alle Verbindungen wurden durch Einkristall‐Röntgenstrukturanalyse, Massenspektrometrie, NMR‐ und IR‐Spektroskopie charakterisiert. Darüber hinaus wurde die sehr instabile Phosphanylboran‐Kette PH2BH2PH2BH2‐NMe3 (1) synthetisiert. Dichtefunktionalrechnungen geben Einblick in die Thermodynamik dieser Reaktionen.
Degree of Biomimicry of Artificial Spider Silk Spinning Assessed by NMR Spectroscopy
Authors: Otikovs Martins , Andersson Marlene , Jia Qiupin , Nordling Kerstin , Meng Qing , Andreas Loren B. , Pintacuda Guido , Johansson Jan , Rising Anna , Jaudzems Kristaps 
Published: August 2017

AbstractBiomimetic spinning of artificial spider silk requires that the terminal domains of designed minispidroins undergo specific structural changes in concert with the β‐sheet conversion of the repetitive region. Herein, we combine solution and solid‐state NMR methods to probe domain‐specific structural changes in the NT2RepCT minispidroin, which allows us to assess the degree of biomimicry of artificial silk spinning. In addition, we show that the structural effects of post‐spinning procedures can be examined. By studying the impact of NT2RepCT fiber drying, we observed a reversible beta‐to‐alpha conversion. We think that this approach will be useful for guiding the optimization of artificial spider silk fibers.
Water absorption behavior and kinetics of glass fiber/waste cotton fabric hybrid composites
Authors: Bodur M. Safa , Englund Karl , Bakkal Mustafa 
Published: August 2017

ABSTRACTThis study deals with the effect of water absorption on the physical and mechanical properties of the glass fiber/waste cotton fabric hybrid composites compared to the samples with maleic anhydride (MA) as coupling agent. Water absorption studies were performed for four different soaking times of 100, 250, 500, and 1000 h at room temperature. To clearly understand how long this type of composites can endure without any important loss of mechanical properties, tensile and impact tests were performed after 500 and 1000 h of water immersion time. Results showed that using MA can reduce water sorption values significantly from 5% to 1.5%. In addition, very limited variations in tensile properties were explored even after 1000 h of soaking time by the presence of MA. On the other hand, impact test results revealed that changes in impact strength values are very complex and different mechanisms play a role with respect to the hybrid formulations. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45506.
Sealing system activated by magnetic induction polymerization
Authors: Marques Fernanda Davi , Nele de Souza Marcio , Gomes de Souza Fernando 
Published: August 2017

ABSTRACTThis work describes the one‐step production of glycerin based polyurethane/magnetite nanocomposites. The polymerization was performed in a nonaqueous dispersion containing the magnetic nanoparticles and the polar monomers under alternating magnetic field. Fourier transform infrared spectroscopy and crosslink degree tests were useful to conclude that the use of magnetic induction (∼3 min at 9300 W) produced results similar to the ones obtained by the conventional polymerization (∼3 h at 80 °C) in a fraction of the required time. A lost circulation fluid control test also was performed under magnetic induction heating and the system containing 5 wt % of the nanoparticles showed the highest reduction of the fluid flow rate. Scanning electron microscopy and probability density function tests of the best material allowed inferring that composite prepared by magnetic induction presents a non‐Gaussian distribution of the diameter, which is directly related to the observed sealing effect. These results showed that proposed polymer/polymerization system can be very useful to the sealing applications. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45549.
Construction of multilayer coatings for flame retardancy of ramie fabric using layer‐by‐layer assembly
Authors: Yan Hongqiang , Zhao Li , Fang Zhengping , Wang Hao 
Published: August 2017

ABSTRACTComplex multilayer coatings composed of α‐zirconium phosphate (ZrP), polyethylenimine (PEI), and ammonium polyphosphate (APP) were constructed via layer‐by‐layer assembly method for flame retardant ramie fabric. Bicomponent PEI/ZrP layers served as insulating barrier coating, and bicomponent PEI/APP layers served as intumescent coating. The flame retardancy of the coated ramie fabric was strongly dependent on the nature of the coatings and the layer‐by‐layer assembly patterns. The coated ramie fabric with inside PEI/ZrP layers and outside PEI/APP layers possessed the most uniform and consistent coating surface morphology, as well as the highest content of N and P elements, resulting in an excellent improvement in flame retardancy of ramie fabrics. When this kind of coated ramie fabric was heated, the inner PEI/ZrP layer effectively prevent oxygen and heat from penetrating into the substrate, and the outer PEI/APP layer exposed to air with good expansion during combustion. The synergistic effect was formed during the combustion process and could impart ramie fabrics with high flame retardancy. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45556.
Enhanced gas separation performance of PSF membrane after modification to PSF/PDMS composite membrane in CO2/CH4 separation
Authors: Suleman Malik Shoaib , Lau K. K. , Yeong Y. F. 
Published: August 2017

ABSTRACTAsymmetric polysulfone (PSF) membrane was developed and modified to PSF/polydimethylsiloxane (PSF/PDMS) composite membrane by dip coating technique. Effect of PDMS coating time on membrane properties was examined by scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, attenuated total reflectance‐Fourier transform infrared, and water contact angle. The increase in PDMS coating time resulted in a decrement in the thermal strength of PSF membrane. Surface contact angle values revealed that increase in PDMS coating time had increased the surface hydrophobicity in membranes. CO2/CH4 separation performance of membranes was evaluated, and an increase in CO2/CH4 ideal selectivity was observed with the increase of PDMS coating time. At feed pressure of 10 bar, the selectivity of PSF has increased up to 65% after dip coating with PDMS for 30 min. Modification of polymeric membrane into composite membrane provided a way forward towards the enhancement of gas separation performance in polymeric membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45650.
Stereogenic‐Only‐at‐Metal Asymmetric Catalysts
Authors: Zhang Lilu , Meggers Eric 
Published: August 2017

AbstractChirality is an essential feature of asymmetric catalysts. This review summarizes asymmetric catalysts that derive their chirality exclusively from stereogenic metal centers. Reported chiral‐at‐metal catalysts can be divided into two classes, namely, inert metal complexes, in which the metal fulfills a purely structural role, so catalysis is mediated entirely through the ligand sphere, and reactive metal complexes. The latter are particularly appealing because structural simplicity (only achiral ligands) is combined with the prospect of particularly effective asymmetric induction (direct contact of the substrate with the chiral metal center). Challenges and solutions for the design of such reactive stereogenic‐only‐at‐metal asymmetric catalysts are discussed.