bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthetic Viruses
Authors: Stauft Charles B , Wimmer Eckard 
Published: February 2018

Abstract

Advances in the synthesis of oligonucleotides have enabled the production of large DNA (deoxyribonucleic acid) molecules that can be tailored with great precision to the demands of scientists. New fields of the life sciences, synthetic biology, have been born from these advances. Using established methods of molecular cloning and reverse genetics, it has become possible to produce functional viruses using a digital template or design. The use of synthetic biology to construct viruses has proceeded rapidly because of falling costs in oligonucleotide synthesis. Synthetic viruses have been used to develop vaccine candidates, test the veracity of archived sequence data and reconstitute viruses previously thought lost to scientific study. From advent through ascension, synthetic viruses have elicited both scientific promise and public controversy.

Key Concepts

Synthetic virology is the production of live virus using a complete reference sequence. No natural viral copy is necessary – the parent of the virus is the computer.

Synthetic virology combines the technologies of DNA synthesis and reverse genetics.

RNA viruses typically have short genomes that make them ideal for synthesis.

Viruses can be attenuated through rational
in silico
design of novel sequences incorporating hundreds to thousands of silent nucleic acid mutations.

Using modern RNA and DNA extraction methodologies, viral genetic information can be sequenced and used to ‘resurrect’ viruses once thought extinct.
Respiratory Syncytial Virus: Immunisation and Prophylaxis
Authors: Barr Rachael , Drysdale Simon B 
Published: February 2018

AbstractRespiratory syncytial virus (RSV) is the second most common cause of mortality in infants worldwide after malaria and the leading cause of hospitalisation in infants in many countries. It is also associated with high levels of morbidity and mortality in older adults (those over 60 years of age). These high levels of healthcare utilisation result in huge associated healthcare costs. As such, the development of an RSV vaccine is listed as a leading global priority by the World Health Organization (WHO). There is a monoclonal antibody (palivizumab) licensed to prevent RSV infection, but it is only used in high‐income countries for the most high‐risk infants owing to its very high cost. The development of an RSV vaccine/prophylactic agent has been hampered by an incomplete understanding of the immunopathogenesis of RSV infection, although many are currently undergoing clinical trials. Adding a new vaccine to the existing vaccine schedules will also present many challenges.Key ConceptsRespiratory syncytial virus (RSV) is a leading cause of morbidity and mortality worldwide in infants, children and older adults.Agents to prevent severe RSV infection are needed to reduce this burden of disease.The immunopathogenesis of RSV infection is incompletely understood, hampering the development of a vaccine.Palivizumab, a monoclonal antibody, is licensed for use in high‐risk infants, but is extremely expensive, and thus newer agents are required.Many RSV vaccines and novel prophylactic monoclonal antibodies are in development, although a licensed product is likely to still be many years away.After a vaccine becomes licensed, there is still a need to ensure that it can be incorporated into the existing vaccine schedules.
Calcium and Bioenergetics
Authors: Jadiya Pooja , Tomar Dhanendra 
Published: February 2018

Abstract

Calcium (Ca
2+
) is one of the most abundant divalent cations found in the biological systems and has numerous vital roles in cellular physiology and pathophysiology. It is involved in the regulation of ionic homeostasis in the cytosol and different cellular organelles. The Ca
2+
directly regulates cellular bioenergetics, cell survival/death and acts as a messenger to regulate various cellular signalling events. Mitochondria, the bioenergetics hub of the cell, are one of the major reservoirs of cellular Ca
2+
. The Ca
2+
plays a major role in shaping the metabolic outcome of the mitochondria and whole cell. In recent years, the molecular identity of a mitochondrial Ca
2+
uniporter (MCU) has been revealed along with various regulators. However, the molecular mechanism of uniporter regulation in different stimuli and other determinants of mitochondrial Ca
2+
homeostasis are still elusive. In this article, we present the current understanding of cytosolic/mitochondrial Ca
2+
homeostasis, its role in energy metabolism and cell survival and its involvement in different cell systems and tissue/organ physiology.

Key Concepts

Ca
2+
signalling is the key determinant for cellular metabolism and bioenergetics.

Mitochondrial Ca
2+
([Ca
2+
]
m
) homeostasis is maintained by balanced [Ca
2+
]
m
influx and efflux.

Mitochondria sequester cytosolic Ca
2+
([Ca
2+
]
c
) into the matrix through the mitochondrial Ca
2+
uniporter MCU.

[Ca
2+
]
m
efflux is mediated by mitochondrial Na
+
/Ca
2+
(NCLX).

[Ca
2+
]
m
uptake modulates spatiotemporal patterns of intracellular Ca
2+
(iCa
2+
) signalling.

Under physiological conditions, [Ca
2+
]
m
uptake regulates bioenergetics and promotes ATP production.

Under pathological conditions, impaired [Ca
2+
]
m
exchange or [Ca
2+
]
m
overload leads to cell death depending on the cell type involved.

Defective [Ca
2+
]
m
signalling is associated with many human diseases.
Vitamin
D
Authors: Carlberg Carsten 
Published: February 2018

Abstract

The fat‐soluble secosteroid vitamin D
3
is synthesised in UV (ultraviolet)‐B exposed human skin. It regulates calcium and phosphorus homeostasis and thus plays an important role in bone mineralisation. Moreover, vitamin D
3
contributes to the control of cellular growth and differentiation as well as to the responsiveness of the innate and adaptive immune system. At insufficient sun exposure, the molecule is a true vitamin and needs to be taken up via diet or by direct supplementation with pills. During the past 50 000 years, the need of sufficient vitamin D
3
synthesis acted an evolutionary driver for skin lightening of anatomically modern humans migrating out of Africa. The vitamin D
3
metabolite 1α,25‐dihydroxyvitamin D
3
is the exclusive high‐affinity ligand of the transcription factor vitamin D receptor and has a direct effect on the expression of >1000 genes. Thus, vitamin D
3
is a modulator of the human epigenome and transcriptome in more than half of all human tissues and cell types.

Key Concepts

In UV‐B exposed human skin, the cholesterol precursor 7‐dehydrocholesterol converts to pre‐vitamin D
3
and then isomerises in a nonenzymatic reaction into vitamin D
3
.

Lifestyle changes significantly reduced the average endogenous vitamin D
3
production in human and caused vitamin D deficiency in most human populations.

Vitamin D
3
is a biologically inert molecule and is enzymatically converted in a two‐step reaction to the nuclear hormone 1,25(OH)
2
D
3
.

25(OH)D
3
serum levels are used as biomarker for the vitamin D status.

Only vertebrates have a full vitamin D endocrine system, formed by plasma transport proteins, metabolising enzymes and a high‐affinity receptor.

The migration of modern humans to less sunny regions in Asia and Europe caused an evolutionary pressure for genetic adaptation in form of gradual skin lightening for more efficient vitamin D
3
production.

The genome‐wide VDR binding pattern is rather cell‐specific, which has an impact on the panel of vitamin D target genes in VDR expressing tissues and cell types.

Vitamin D
3
has a direct effect on the accessibility of chromatin, that is it serves as a modulator of the epigenome.

Humans have an individual response to vitamin D
3
, referred to a vitamin D response index, which allows segregation into high, mid and low responders.

The vitamin D response index suggests for each individual a vitamin D
3
supplementation protocol that will direct to a personal optimal vitamin D status.
Evaluation of surface and shallow depth dose reductions using a Superflab bolus during conventional and advanced external beam radiotherapy
Authors: Yoon Jihyung , Xie Yibo , Zhang Rui 
Published: February 2018

AbstractThe purpose of this study was to evaluate a methodology to reduce scatter and leakage radiations to patients’ surface and shallow depths during conventional and advanced external beam radiotherapy. Superflab boluses of different thicknesses were placed on top of a stack of solid water phantoms, and the bolus effect on surface and shallow depth doses for both open and intensity‐modulated radiotherapy (IMRT) beams was evaluated using thermoluminescent dosimeters and ion chamber measurements. Contralateral breast dose reduction caused by the bolus was evaluated by delivering clinical postmastectomy radiotherapy (PMRT) plans to an anthropomorphic phantom. For the solid water phantom measurements, surface dose reduction caused by the Superflab bolus was achieved only in out‐of‐field area and on the incident side of the beam, and the dose reduction increased with bolus thickness. The dose reduction caused by the bolus was more significant at closer distances from the beam. Most of the dose reductions occurred in the first 2‐cm depth and stopped at 4‐cm depth. For clinical PMRT treatment plans, surface dose reductions using a 1‐cm Superflab bolus were up to 31% and 62% for volumetric‐modulated arc therapy and 4‐field IMRT, respectively, but there was no dose reduction for Tomotherapy. A Superflab bolus can be used to reduce surface and shallow depth doses during external beam radiotherapy when it is placed out of the beam and on the incident side of the beam. Although we only validated this dose reduction strategy for PMRT treatments, it is applicable to any external beam radiotherapy and can potentially reduce patients’ risk of developing radiation‐induced side effects.
Electromagnetic analysis of semi‐interpenetrating polymer network of fullerene‐based polyacrylonitrile and polyaniline
Authors: Kamal Meet , Jafri Mohd Meraj , Singh Dhruv K. , Shami Trilok C. , Baskey Himanshu B. 
Published: February 2018

AbstractA semi‐interpenetrating polymer network (IPN) of fullerene‐based polyacrylonitrile and polyaniline is synthesized. The fabricated IPN is characterized by infrared spectroscopic technique, differential scanning calorimetric analysis, thermogravimetric analysis (TGA), conductivity analysis, field emission scanning electron microscopic techniques, transmission loss, complex permittivity, and permeability characteristics. The IPN was characterized by infrared spectroscopy (IR), which showed bands of fullerene at 525 and 1,602 cm−1, for polyacrylonitrile (PAN) at 3,006, 1,408, 1,370, and 2,237 cm−1, and for polyaniline (PANI), it reveals peaks at 3,423, 3,085, 1,583, 1,629, 1,268, 1,314, 907, 989, and 2,929 cm−1, respectively. Shifting in band positions indicates the interpenetration of the reacting species. The maximum value of ε′, ε′′, tanδεr, μ′, μ′′, and tanδμr for IPN “A” and “B” has reached 5.06, 2.26, 2.80, 0.90, 0.83, 2.3, 6.1, 3.69, 3.96, 1.0, 0.85, and 2.77, respectively, depicting relatively higher permittivity and permeability of sample B over A. The maximum value of transmission loss for sample A and B has reached 9.8 and 9.9 dB, respectively, which implies enhanced electromagnetic behavior of sample B over A. The maximum value of conductivity of IPN sample “A” and “B” is found to be 1.7 and 2.5 S/m, respectively. Sample “B” shows enhanced conductivity over sample A. Permeability, permittivity, transmission loss, and conductivity data reveal the conducting character of polymer network. Thermogravimetric analysis is used to calculate initial thermal decomposition of IPN sample “A” and “B” which are found to be at 250 and 370°C, respectively. Differential scanning calorimetric (DSC) thermogram of IPN samples A and B shows glass transition temperature (Tg) at 433.7 and 440.8°C, respectively. The microstructure of polymer network is analyzed using field emission scanning electron microscopy (FE‐SEM) having 100‐nm resolution which reveals clear dual phase morphology of semi‐IPN films.
Influence of the structure of polymer fiber composites on the analysis of the zeta potential
Authors: Petrinić Irena , Bukšek Hermina , Luxbacher Thomas , Pušić Tanja , Bischof Sandra 
Published: February 2018

ABSTRACTThis article addresses the questions about the influence of surface area, roughness, and sample mounting on the zeta potential analysis. A series of knitted yarns and fabrics of cotton and modacryl and their blends represent a real‐life model system to study these effects. The combination of the natural cotton and the man‐made modacryl makes possible to study the effect of the different origin for surface and interfacial charge and the surface area‐weighted contributions to the average zeta potential of a chemically heterogeneous composite material. In our study, two measuring cells of the SurPASS electrokinetic analyzer were used, namely the Cylindrical Cell and the Adjustable Gap Cell. Comparison of the results obtained in two different measuring cells was related to the measured material. We used the Cylindrical Cell for both the zeta potential analysis of yarn and knitted fabrics and compared these results with data obtained for knitted fabrics using the Adjustable Gap Cell. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2018,135, 46227.
Preparation of high‐k composites with low dielectric loss based on the double‐layer coaxial structure of inorganic/polymer
Authors: Zhao Yuhui , Luo Li , Tang Hongfeng , Zhou Zheng , Chen Guang‐Xin , Li Qifang 
Published: February 2018

ABSTRACTThis study presents a novel and simple modification of cladding multiwalled carbon nanotubes (MWCNTs) using organic polymer and inorganic nanoparticles to synthesize a product, which has a double‐cladding coaxial structure and can be applied as filler in the dielectric field. The first layer of MWCNTs was coated with polyaniline (PANI) through the oxidation–reduction reaction mechanism using Ce(NH4)2(NO3)6 as oxidizing agent and metal precursor of cerium oxide. Cerium ions on the second cladding layer of MWCNTs were directly deposited from the solution to the surface of the PANI layer forming the double‐cladding hybrid (CeO2/PANI@MWCNTs). The external inorganic layer provides an insulating shell, which can prevent the contact between the conductive particles and hinder the migration of electrons between the MWCNTs. The intermediate layer of PANI provides the bonding between CeO2 and the conductive core of MWCNTs, which also shows lower conductivity than carbon nanotubes. The CeO2/PANI@MWCNTs were compounded with epoxy (EP) resin and formed a dielectric material with the advantage of reducing dielectric loss while ensuring high dielectric constant. The dielectric constant of the coated MWCNTs/EP composites was 194.90 at 103 Hz with the content of fillers reaching 30 wt %, which is 28 times that of the pure EP. Accordingly, the dielectric loss of 30 wt % coated MWCNTs/EP composites was only 0.09 at 103 Hz, which is only 2.25 times that of the pure EP. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46299.
Stable anion exchange membranes derived from fluorinated poly(aryl ethers) with quaternized fluorene units for fuel cell applications
Authors: Gao Qi , Pan Xueting , Buregeya Providence Ingabire , Lu Yao , Zhang Xulve , Yan Xiaobo , Hu Zhaoxia , Chen Shouwen 
Published: February 2018

ABSTRACTA series of fluorinated poly(aryl ethers) containing benzyltrimethyl quaternary ammonium functionalized fluorene units (QPFAE) are synthesized via condensation polymerization, chloromethylation, and quaternization. Ionomer structure and the ion exchange capacity are confirmed by 1H‐nuclear magnetic resonance spectroscopy. Other characterization techniques such as Fourier transform infrared spectroscopy, atomic force microscopy, thermogravimetric analysis, gel permeation chromatography, electrochemical impedance spectroscopy, Fenton, water‐swelling, and hydrolytic aging tests are used to evaluate the physicochemical properties of the as‐prepared QPFAE membranes. For the QPFAE membranes with ion exchange capacity of 0.95–1.94 mmol/g, they displayed low water uptake and methanol permeability (4.59–26.1 × 10−8 cm2/s at 25 °C), fairly good dimensional stability, high mechanical toughness, as well as fine thermal‐oxidative‐hydrolytic stability and ion conductivity at least 10 mS/cm. The membranes also showed clear hydrophilic/hydrophobic phase‐separation morphology. Furthermore, the QPFAE membranes could endure harsh basic conditions (1–4 mol/L NaOH solution) at 60 and 80 °C at least 240 h, keeping rather high mechanical toughness and ion conduction capability during the aging test. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46301.
Crystal phase transition dependence of the energy storage performance of poly(vinylidene fluoride) and poly(vinylidene fluoride‐hexafluoropropene) copolymers
Authors: Xia Weimin , Zhou Zhenji , Liu Yang , Wang Qing , Zhang Zhicheng 
Published: February 2018

ABSTRACTLarge‐scale mechanical stretching has been performed to modify the crystal phase structures of the pristine poly(vinylidene fluoride) (PVDF) and its copolymer poly(vinylidene fluoride‐hexafluoropropylene) [P(VDF‐HFP)] with various molar contents HFP in an attempt to improve their energy storage performances. It is found that the physical stretched PVDF and P(VDF‐HFP) 95.5/4.5 mol % films have a phase transition from the nopolar α‐phase to highly polar β‐phase, which is different from the P(VDF‐HFP) films with relative high HFP molar contents (α to γ phases). The following results show that the phase transition in these PVDF‐based polymers has a significant effect on their dielectric and energy storage performances. On account of the reformation of the crystalline property and elimination of the impurity defects, an ultra‐high breakdown electric field of ∼900 MV/m has been obtained in all the stretched samples. Consequently, the higher discharged energy densities of 27.1 and 27.7 J/cm3 are calculated from the D–E loops of the β‐PVDF and β‐P(VDF‐HFP) 95.5/4.5 mol % films, respectively. Regarding their excellent discharging energy density of ∼10 J/cm3 under 600 MV/m for thousands of times, the stretched PVDF and its copolymer P(VDF‐HFP)s are promising candidates for high power capacitors applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46306.
Poly(vinyl alcohol)/chitosan/honey/clay responsive nanocomposite hydrogel wound dressing
Authors: Noori S. , Kokabi M. , Hassan Z. M. 
Published: February 2018

ABSTRACTMany efforts have been made to develop modern wound dressings to overcome limitations of traditional ones. Smart nanocomposite hydrogels are appropriate candidates. In this work, a novel responsive nanocomposite hydrogel based on poly(vinyl alcohol)/chitosan/honey/clay was developed and evaluated as a novel wound dressing. The morphology and properties of synthesized nanocomposite hydrogels loaded with honey as a drug model were investigated. The exfoliated morphology of nanocomposite was confirmed by X‐ray diffractometry. Swelling studies were performed at 20 and 37 °C at various pH. The results showed that swelling increased as a result of temperature rise and maximum swelling occurred at a pH of 2. In vitro release of honey was also studied at the same conditions. Corresponding results indicated faster honey release rate at higher pH values. MTT results exhibited no cytotoxicity in nanocomposite hydrogel system. Investigation of antibacterial activity revealed more than 99% antibacterial activity for proposed system. In vivo results confirmed the wound healing ability of developed system. Generally, appropriate properties of proposed system made it ideal in wound dressing applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46311.
Efficient bioconversion of oleuropein from olive leaf extract to antioxidant hydroxytyrosol by enzymatic hydrolysis and high‐temperature degradation
Authors: Liu Min , Yong Qiang , Yu Shiyuan 
Published: February 2018

AbstractHydroxytyrosol (HT), a powerful antioxidant, clears free radicals and exhibits many biological activities. Because contents of HT are low in natural sources, bioconversion of oleuropein (OLE) to HT is of increasing interest. A biotechnological process was investigated to produce HT from OLE presented in olive leaf extract. Enzymatic hydrolysis using two cellulases with high β‐glucosidase activity, Novozymes CTec2 and commercial cellulase KDN (Qingdao, People's Republic of China) was carried out at 50 °C for 12 H followed by raising the temperature to 90 °C for chemical hydrolysis. After 48 H of hydrolysis, an OLE degradation rate of 100% and a HT yield of 86–88% were achieved. These cellulases degrade OLE and release a glucose molecule. Chemical hydrolysis at a high temperature promotes the cleavage of ester bond and the formation of HT. This process has a promising alternative for production of HT comparing with acid hydrolysis which not only causes significant pollution to the environment but also makes difficult to the subsequent separation.
Differentiation of 3D‐shape‐controlled mouse neural stem cell to neural tissues in closed agarose microchambers
Authors: Matsushiro Yuki , Kato‐Negishi Midori , Onoe Hiroaki 
Published: February 2018

AbstractThis paper describes three‐dimensional (3D) tissue shape control of mouse neural stem cell (mNSC) micro tissues by using closed agarose microchambers for effective differentiation induction of neurons in vitro. Our agarose microchambers, made by micromolding, can be sealed with an agarose sheet to form the mNSC tissues along the shape of microchambers. We constructed lane‐shaped mNSC tissues with different width (∼60–210 μm) and thickness (∼25–95 μm) dimensions and induced differentiation to neurons with differentiation medium. We found that in thick tissues (thickness: >60 μm), distribution of differentiated neurons was not uniform, whereas in thin tissues (thickness: ∼30 μm), differentiated neurons were uniformly distributed with high differentiation efficiency. Our system to construct in vitro 3D neural tissues having uniformly distributed neurons at high differentiation ratio, could become an effective tool for drug screening using 3D neural tissues and 3D mNSC tissues under differentiation induction.