bluuebunny/crossref_metadata_2025 huggingface dataset:
Small‐Molecule Activators of Glucose‐6‐phosphate Dehydrogenase (G6PD) Bridging the Dimer Interface
Authors: Raub Andrew G. , Hwang Sunhee , Horikoshi Naoki , Cunningham Anna D. , Rahighi Simin , Wakatsuki Soichi , Mochly‐Rosen Daria
Published: June 2019

We recently identified AG1, a small‐molecule activator that functions by promoting oligomerization of glucose‐6‐phosphate dehydrogenase (G6PD) to the catalytically competent forms. Biochemical experiments indicate that the activation of G6PD by the original hit molecule (AG1) is noncovalent and that one C2‐symmetric region of the G6PD homodimer is important for ligand function. Consequently, the disulfide in AG1 is not required for activation of G6PD, and a number of analogues were prepared without this reactive moiety. Our study supports a mechanism of action whereby AG1 bridges the dimer interface at the structural nicotinamide adenine dinucleotide phosphate (NADP+) binding sites of two interacting G6PD monomers. Small molecules that promote G6PD oligomerization have the potential to provide a first‐in‐class treatment for G6PD deficiency. This general strategy could be applied to other enzyme deficiencies in which control of oligomerization can enhance enzymatic activity and/or stability.
Electrically Conducting Nanocomposites of Carbon Nanotubes and Metal‐Organic Frameworks with Strong Interactions between the two Components
Authors: Schulze Hendrik A. , Hoppe Bastian , Schäfer Malte , Warwas Dawid P. , Behrens Peter
Published: June 2019

Highly integrated nanocomposites of Zr‐based metal‐organic frameworks (MOFs) of the UiO‐66 class and multi‐wall carbon nanotubes (MWCNTs) are prepared by direct crystallization of MOFs in the presence of CNTs. Powder samples with homogeneously distributed and strongly intergrown nanotubes and nanoparticles are obtained. Growth of the MOFs in the presence of CNTs deposited on glass slides yields open or compact coatings of the nanocomposites. The materials combine the high porosity and versatility of MOFs with the high electrical conductivities of CNTs. Upon increasing the amount of CNTs in the synthesis, the electrical conductivity shows a clear percolation behavior. Even with small amounts of CNTs, high conductivities are observed. SEM and TEM pictures show the strong intergrowth between the CNTs and the MOF nanoparticles. Crystallization times are shorter in the presence of CNTs, and CNTs run centrally through the MOF crystals. These facts indicate that the CNTs serve as heterogeneous nucleation centers for the formation of MOF nanocrystals. Sensing experiments performed on the coatings show significant changes in the electrical conductivities of the nanocomposite materials in the presence of different analytes, which are also discernable from the changes observed on bare CNTs. This is further proof for the close interaction between the components of the nanocomposites.
Catalytic Mechanism of CO Oxidation on Three‐Silicon‐Doped Hexagonal Boron Nitride
Authors: Ma Chaoqun , Liu Bingping , Wang Hai , Yan Shihai
Published: June 2019

Doped nanomaterials show extremely high atom efficiency, low cost, high stability and activity for CO oxidation, bridging the gap between homogeneous and heterogeneous catalysis. The catalytic mechanism of CO oxidation on three‐silicon‐doped h‐BN is reported. The adsorption of O2 is more advantageous than CO. The electron transfer from the dopant activates the adsorbed O2 and initiates the following CO oxidation. The oxidation process includes O2 adsorption, electron transfer, CO adsorption, oxygen transfer, and CO2 desorption. The energy barriers for the generation of two CO2 molecules in N vacancy dopant are 0.50 and 0.33 eV, respectively. The enhanced catalytic performance indicates that three‐silicon‐doped h‐BN has potential applications to fabricate low cost and high activity BN‐based metal‐free catalysts.
Influences of lighting time course and background on categorical colour constancy with RGB‐LED light sources
Authors: Ma Ruiqing , Liao Ningfang , Yan Pengfei , Shinomori Keizo
Published: June 2019

Some previous studies have investigated the influence of the lighting time course and viewing background on the colour constancy using two‐dimensional flat stimuli simulated on a monitor. In the present study, we investigated the categorical colour constancy in real scenes by manipulating (a) the lighting time course, that is, adaptation period to the illuminant (brief adaptation or complete adaptation) and (b) the background structure of a stimulus (a uniform gray background with an approximately 25% spectral reflectance or a multicolour background consisting of the Macbeth ColorChecker and some fruit models). The neutral (u′= 0.1994,v′= 0.4671), red (u′= 0.2433,v′= 0.4622), green (u′= 0.1525,v′= 0.4697), blue (u′= 0.2049,v′= 0.4198), and yellow (u′= 0.1892,v′= 0.5112) illuminants were produced by an RGB‐LED lamp. For each chromatic illumination condition, subjects categorized 240 surfaces with Munsell Value 5/ in four viewing conditions with different combinations of the lighting time course and the background structure. A total of seven subjects participated in experiments with red and green illuminants and five subjects with blue and yellow illuminants. The results showed that the constancy index was the lowest (0.66) in the brief adaptation and gray background condition and the highest (0.74) in the complete adaptation and multicolour background condition. The results suggest that increasing the adaptation period alone or adding chromatic cues in the background with a brief adaptation can help to improve the colour constancy, and a time‐taking reference to surrounding coloured objects with the long presentation of the illuminant may also contribute to obtaining colour constancy.
In‐Situ Growth of Gadolinium Phthalocyaninato Sandwich Complexes on the Ag(111) Surface
Authors: Urgel José I. , Écija David , Vijayaraghavan Saranyan , Pörtner Mathias , Bocquet Marie‐Laure , Auwärter Willi , Barth Johannes V.
Published: June 2019

We report a low‐temperature scanning tunneling microscopy investigation of the in‐situ growth of gadolinium phthalocyaninato complexes by combined deposition of free‐base phthalocyanines and gadolinium atoms on a smooth Ag(111) substrate. A careful control of the stoichiometry allows the expression of a multilevel structurecomposed of irregularly distributed Gdx‐1(Pc)x complexes, x=2–5, thus paving new avenues for surface‐confined columnar growth.
Record Low Ionization Potentials of Alkali Metal Complexes with Crown Ethers and Cryptands
Authors: Tkachenko Nikolay V. , Sun Zhong‐Ming , Boldyrev Alexander I.
Published: June 2019

Electronic properties of series of alkali metals complexes with crown ethers and cryptands were studied via DFT hybrid functionals. For [M([2.2.2]crypt)] (M=Li, Na, K) extremely low (1.70–1.52 eV) adiabatic ionization potentials were found. Such low values of ionization energies are significantly lower than those of alkali metal atoms. Thus, the investigated complexes can be defined as superalkalis. As a result, our investigation opens up new directions in the designing of chemical species with record low ionization potentials and extends the explanation of the ability of the cryptates and alkali crown ether complexes to stabilize multiple charged Zintl ions.
On‐Surface Synthesis and Spectroscopic Characterization of Laterally Extended Chevron Graphene Nanoribbons
Authors: Teeter Jacob D. , Zahl Percy , Mehdi Pour Mohammad , Costa Paulo S. , Enders Axel , Sinitskii Alexander
Published: June 2019

We report the on‐surface synthesis and spectroscopic study of laterally extended chevron graphene nanoribbons (GNRs) and compare them with the established chevron GNRs, emphasizing the consistency of bandgap reduction of semiconducting GNRs with increased width. The laterally extended chevron GNRs grown on Au(111) exhibit a bandgap of about 2.2 eV, which is considerably smaller than the values reported for chevron GNRs in similar studies.
Direct Conversion of CO2 to Multi‐Layer Graphene using Cu–Pd Alloys
Authors: Molina‐Jirón Concepción , Chellali Mohammed Reda , Kumar C. N. Shyam , Kübel Christian , Velasco Leonardo , Hahn Horst , Moreno‐Pineda Eufemio , Ruben Mario
Published: June 2019

A straightforward one‐step process was developed, in which CO2 gas is directly converted into multi‐layer graphene via atmospheric pressure chemical vapor deposition (APCVD). A bimetallic alloy film based on Cu and Pd was employed as the catalyst and substrate. In this study, we found that the quantity of Cu required for the CO2 conversion process is high (>82 at %). The findings gained in this study serve as a foundation for further studies of metallic alloys for the thermo‐reduction of CO2 to graphene under CVD conditions.
The importance of sample size in marine megafauna tagging studies
Authors: Sequeira A. M. M. , Heupel M. R. , Lea M.‐A. , Eguíluz V. M. , Duarte C. M. , Meekan M. G. , Thums M. , Calich H. J. , Carmichael R. H. , Costa D. P. , Ferreira L. C. , Fernandéz‐Gracia J. , Harcourt R. , Harrison A.‐L. , Jonsen I. , McMahon C. R. , Sims D. W. , Wilson R. P. , Hays G. C.
Published: June 2019

Telemetry is a key, widely used tool to understand marine megafauna distribution, habitat use, behavior, and physiology; however, a critical question remains: “How many animals should be tracked to acquire meaningful data sets?” This question has wide‐ranging implications including considerations of statistical power, animal ethics, logistics, and cost. While power analyses can inform sample sizes needed for statistical significance, they require some initial data inputs that are often unavailable. To inform the planning of telemetry and biologging studies of marine megafauna where few or no data are available or where resources are limited, we reviewed the types of information that have been obtained in previously published studies using different sample sizes. We considered sample sizes from one to >100 individuals and synthesized empirical findings, detailing the information that can be gathered with increasing sample sizes. We complement this review with simulations, using real data, to show the impact of sample size when trying to address various research questions in movement ecology of marine megafauna. We also highlight the value of collaborative, synthetic studies to enhance sample sizes and broaden the range, scale, and scope of questions that can be answered.
Soil characteristics are associated with gradients of big sagebrush canopy structure after disturbance
Authors: Barnard David M. , Germino Matthew J. , Arkle Robert S. , Bradford John B. , Duniway Michael C. , Pilliod David S. , Pyke David A. , Shriver Robert K. , Welty Justin L.
Published: June 2019

Reestablishing shrub canopy cover after disturbance in semi‐arid ecosystems, such as sagebrush steppe, is essential to provide wildlife habitat and restore ecosystem functioning. While several studies have explored the effects of landscape and climate factors on the success or failure of sagebrush seeding, the influence of soil properties on gradients of shrub canopy structure in successfully seeded areas remains largely unexplored. In this study, we evaluated associations between soil properties and gradients in sagebrush canopy structure in stands that had successfully reestablished after fire and subsequent seeding treatments. Using a dataset collected across the Great Basin, USA, of sagebrush stands that had burned and reestablished between 1986 and 2013, we tested soil depth and texture, soil surface classification, biological soil crusts plus mean historical precipitation, solar heatload, and fire history as modeling variables to explore gradients in sagebrush canopy structure growth in terms of cover, height, and density. Deeper soils were associated with greater sagebrush canopy structure development in terms of plant density and percent cover, coarser textured soils were associated with greater sagebrush cover and density, and more clayey soils were typically associated with greater height. Biological crust presence was also positively associated with enhanced sagebrush canopy growth, but adding more demographically or morphologically explicit descriptions of biocrust communities did not improve explanatory power. Increasing heatload had a negative effect on sagebrush canopy structure growth, and increased mean annual precipitation was only associated with greater sagebrush height. Given that conservation and restoration of the sagebrush steppe ecosystems has become a priority for land managers, the associations we identify between gradients in post‐fire sagebrush canopy structure growth and field‐identifiable soil characteristics may improve planning of land treatments for sagebrush restoration and the understanding of semi‐arid ecosystem functioning and post‐disturbance dynamics.
[Cp2Mo(OH)(OH2)]+‐Catalyzed Hydrolysis of Mono‐ and Difunctional Ethers: Theoretical Understanding of Their Divergent Reactivity
Authors: Álvarez Daniel , Castro‐López Elena , Fernández‐Pulido Yoana , Menéndez M. Isabel , López Ramón
Published: June 2019

The reaction mechanism of [Cp2Mo(OH)(OH2)]+‐catalyzed hydrolysis of ethyl vinyl, divinyl, and diethyl ethers was theoretically investigated. The reaction pathway evolving through the coordination of the ether oxygen to Mo is notably disfavored, as experimentally suggested. This is the only operative coordination mode for diethyl ether and explains why this monofunctional ether is not hydrolyzed by molybdocenes. However, difunctional ethers containing a functionality susceptible to activation like the vinyl group present an alternative reaction pathway proceeding through the coordination of the vinyl terminal carbon to Mo with accessible rate‐determining Gibbs energy barriers of 29.3 kcal/mol (divinyl ether) and 22.2 kcal/mol (ethyl vinyl ether). In these cases, the catalyst withdraws electron density from the unsaturated bonds and prepares the group for an easy OH‐nucleophilic attack. This explains the molybdocene‐catalyzed hydrolysis of ethyl vinyl ether experimentally observed and, more interestingly, reveals what the crucial role of the functional groups linked to the ether oxygen really is in the viability of these reactive processes.
Redox‐Active Monopyrrolotetrathiafulvalene‐Based Rotaxane Incorporating the Dihydroazulene/Vinylheptafulvene Photo/Thermoswitch
Authors: Kilde Martin Drøhse , Kristensen Rikke , Olsen Gunnar , Jeppesen Jan O. , Nielsen Mogens Brøndsted
Published: June 2019

A dumbbell‐shaped molecule with a central monopyrrolo‐tetrathiafulvalene (MPTTF) unit and a 1,1‐dicyano‐dihydroazulene (DHA) photoswitch as one of the two end‐groups was prepared and subsequently converted into a [2]rotaxane with cyclobis(paraquat‐p‐phenylene) (CBPQT4+) as the ring component. Investigations revealed that both the DHA and its vinylheptafulvene (VHF) photoisomer prevent deslipping of CBPQT4+. It was found that the presence of the CBPQT4+ ring on the MPTTF‐DHA dumbbell changes the rate of the thermal back‐conversion of VHF into DHA, i.e., this conversion was found to be accelerated by the presence of the positively charged CBPQT4+ ring. Studies also showed that DHA forms a weak complex with CBPQT4+, which seems to originate from weak interactions between the cyano group located on DHA and the bipyridinium α‐protons on CBPQT4+. The rotaxane was subjected to various oxidation experiments, but these were, unfortunately, accompanied by some decomposition of the molecule; yet, movement of the CBPQT4+ ring from the MPTTF unit towards the DHA moiety seems to occur upon oxidation of the MPTTF unit, promoted by the weak interaction between the DHA moiety and CBPQT4+.
Kinetic study of lithium orthosilicate pellets for high‐temperature chemical heat pumps
Authors: Kim Seon Tae , Nihei Takuya , Kurahashi Chisato , Hoshino Hitoshi , Takasu Hiroki , Kato Yukitaka
Published: June 2019

Lithium orthosilicate/carbon dioxide/zeolite (Li4SiO4/CO2/zeolite) chemical heat pump (CHP) systems have been discussed for storage and transformation of surplus thermal energy (at ∼650°C) generated from renewable and nuclear energy systems. Tablet forms of Li4SiO4 (referred to as K‐tablets) have been developed with a new pelletizing method for practical application in packed bed CHP reactors. To understand the carbonation and decarbonation mechanisms of K‐tablets, a double‐shell model was suggested and used for explaining experimental results. Isothermal carbonation, decarbonation, and cyclic experiments were conducted under several reaction temperatures for characterization of the K‐tablet. The developed K‐tablet exhibited superior carbonation and decarbonation performance compared to pure Li4SiO4 powder at low temperatures, even when the powder was formed into a tablet shape. The K‐tablet also demonstrated enough durability and a stable reacted conversion value (Δx = 0.75) during cyclic experiments under all temperature. Higher kinetic performances of the K‐tablet than those of pure powder at 650°C and 600°C were also confirmed. The K‐tablet exhibited a high Woutput‐max of 9.82 kW/kg‐tablet at 650°C on the 10th cycle and that value was higher than that of the pure powder (3.25 kW/kg‐Li4SiO4) under the same reaction temperature. The developed K‐tablet has sufficient potential as a CHP material for heat transformation of thermal energy at 600°C to 650°C to >700°C.
Predictive value of CCND1/cyclin D1 alterations in the malignant transformation of potentially malignant head and neck disorders: Systematic review and meta‐analysis
Authors: Ramos‐García Pablo , González‐Moles Miguel Ángel , Ayén Ángela , González‐Ruiz Lucía , Gil‐Montoya José Antonio , Ruiz‐Ávila Isabel
Published: June 2019

Background

To evaluate published evidence on the predictive value of CCND1 amplification/cyclin D1 overexpression as malignant transformation risk markers in potentially malignant disorders (PMDs) of the head and neck.

Material and Methods

We searched PubMed, Embase, Web of Science, and Scopus for studies published before June 2018. We conducted a meta‐analysis to quantify the impact of CCND1/cyclin D1 amplification/overexpression on malignant transformation of head and neck PMDs.

Results

Nine studies met inclusion criteria. Quantitative evaluation indicated strong statistically significant association between CCND1/cyclin D1 amplification/overexpression and the progression of head and neck PMD to head and neck squamous cell carcinoma (risk ratio [RR] = 2.04, 95% confidence interval [CI] = 1.37‐3.03, P < .001, and RR = 2.27, 95% CI = 1.32‐3.91, P = .003, respectively). We observed moderate heterogeneity among studies (I2 = 40.7%), and we cannot rule out small‐study effects such as publication bias. The oral cavity subgroup showed the strongest association between CCND1/cyclin D1 amplification/overexpression and progression to cancer.

Conclusion

CCND1/cyclin D1 amplification/overexpression is important to predict the malignant transformation risk of head and neck PMDs, especially oral PMDs.
Neuroblastoma involving urinary bladder: A rare type of tumor with diagnostic ambiguity
Authors: Han Lin Aung , Khine Win , Lin Tin Maung , Thu Min
Published: June 2019

Introduction

Neuroblastoma of urinary tract is an extremely rare type of tumor and only a few cases have been reported worldwide.

Case presentation

We presented an adult case of neuroblastoma involving urinary bladder. Patient was a 24‐year‐old man with a history of repeated attack of hematuria. Patient underwent cystoscopy and transuretheral resection of bladder tumor. Biopsy result was “Blastema cell (suggestive of neuroblastoma) with immature ganglion cells.” Immunohistochemistry workup was continued and neuron‐specific enolase and S100 staining were positive. Patient lost to further follow‐up visit.

Conclusion

Although neuroblastoma of skin and peripheral nerve is not a rare disease entity, involvement of deeper structures (especially urinary bladder) is exceptional.
The modulatory effects of luteolin on cyclic AMP/Ciliary neurotrophic factor signaling pathway in experimentally induced autoimmune encephalomyelitis
Authors: El‐Deeb Omnia Safwat , Ghanem Heba Bassiony , El‐Esawy Rasha Osama , Sadek Mona Tayssir
Published: June 2019

Multiple sclerosis (MS) is considered to be an autoimmune disorder of the central nervous system (CNS) manifested by chronic inflammation. Although its etiology is not completely understood, inflammation and apoptosis are known to be major players involved in its pathogenesis. Luteolin, the naturally occurring flavonoid, is known by strong antioxidant and anti‐inflammatory properties, yet research studies about its therapeutic role in MS are still lacking. The study aimed to provide insight into effects of luteolin in experimental autoimmune encephalomyelitis (EAE) by monitoring inflammatory, apoptotic, and antioxidant biochemical parameters in addition to histological examination findings. The study included 45 adult female Wistar rats allocated to three equal groups: (a) group I: control group, (b) group II: EAE group, EAE was induced by single intradermal injection of 0.2 mL inoculum comprising 20‐μg recombinant rat myelin oligodendrocyte glycoprotein (MOG), and (c) group III: luteolin‐treated EAE group, luteolin was given in a dose of 10 mg/kg/day, i.p. All groups were subjected to assessment of brain ciliary neurotropic factor (CNTF) mRNA gene expression and measurement of cleaved caspase 3, nuclear factor kappa B (NF‐κB), cyclic AMP (cAMP), and macrophage inflammatory protein 1 alpha (MIP‐1α) by the ELISA technique, total antioxidant capacity (TAC) level is assessed spectrophotometrically. Compared with the EAE group, luteolin‐treated EAE group showed upregulation of CNTF expression and significant increase in cAMP and TAC levels, while it showed significant decrease in cleaved caspase 3, NF‐κB, and MIP‐1α levels. Based on our data herein, luteolin may provide a promising preclinical therapeutic line in MS being anti‐inflammatory, antiapoptotic, and neurotrophic agent. © 2019 IUBMB Life, 71(9):1401–1408, 2019
Abnormal platelet amyloid‐β precursor protein metabolism in SAMP8 mice: Evidence for peripheral marker in Alzheimer's disease
Authors: Chen Lizhi , Xu Shicheng , Wu Tong , Shao Yijia , Luo Li , Zhou Lingqi , Ou Shanshan , Tang Hai , Huang Wenhua , Guo Kaihua , Xu Jie
Published: June 2019

Senescence‐accelerated mouse strains have proved to be an accelerated‐aging model, which mimics numerous features with Alzheimer's disease (AD). Three, six, and nine‐month senescence‐accelerated resistant 1 and senescence‐accelerated prone 8 (SAMP8) mice were used in the current study, to unravel potential mechanisms for dementia and explore new diagnostic approaches for AD. The amyloid‐β (Aβ40) and Aβ42 levels were elevated in hippocampi and platelets from SAMP8, along with a reduced α‐secretase expression and an enhanced β‐secretase expression extent with age, compared to control mice. Furthermore, hippocampal Aβ40 and Aβ42 of SAMP8 were positively correlated with platelet of these mice with aging progression. In addition, β‐γ‐secretase‐modulated proteolytic proceeding of amyloid precursor protein in platelet might work through the PI3K/Akt/GSK3β pathway. These results indicate that platelet could be a potential early marker in the periphery to study the age‐correlative aggregation of the amyloid‐β peptide in patients with AD, while still requiring the considerable study.
Cloud cover and cloud types in the Eurasian Arctic in 1936–2012
Authors: Chernokulsky Alexander , Esau Igor
Published: June 2019

The Arctic is a cloudy place. It has been recognized that the Arctic cloud cover is sensitive to different climatic factors such as sea ice extent and atmospheric circulation indices. Moreover, several influential climate feedbacks, for example, the summertime cloud‐radiation feedback, have been recognized. Yet, the cloud cover studies were limited in time to the satellite era observations and fragmentary data sets from meteorological stations. Here, we present the complete long‐term cloud records from 86 meteorological stations in the Eurasian Arctic. The stations are located on the coast and islands of the region from the Barents to Chukchi Seas. Thus, this study is complementing and extending the study by Chernokulsky et al. (2017) where the cloud data from the Norwegian through Kara Seas were presented. Our data set comprises the entire period of observations at each station. However, we present the area‐wide analysis only over the historical period of 1936–2012 when there were sufficient density of stations and cloud records for the coherent analysis. The total cloud cover, which on multiannual average constitutes 69–74% in different areas, increases in the warmer periods. The strongest increase is found in the convective cloud cover, particularly in the Chukchi Sea. We observe statistical evidence of transition between stratiform and convective cloud types. The cloud characteristics reveal the strongest correlations with the Atlantic circulation indices and the sea ice concentration in all Eurasian Arctic areas. The correlations with the Pacific circulation indices are much less significant. The obtained cloud data sets disclose much smaller scale features and variability, which deserve further research.
Dendritic Polyglycerol‐Derived Nano‐Architectures as Delivery Platforms of Gemcitabine for Pancreatic Cancer
Authors: Ray Priyanka , Ferraro Magda , Haag Rainer , Quadir Mohiuddin
Published: June 2019

Dendritic polyglycerol‐co‐polycaprolactone (PG‐co‐PCL)‐derived block copolymers are synthesized and explored as nanoscale drug delivery platforms for a chemotherapeutic agent, gemcitabine (GEM), which is the cornerstone of therapy for pancreatic ductal adenocarcinoma (PDAC). Current treatment strategies with GEM result in suboptimal therapeutic outcome owing to microenvironmental resistance and rapid metabolic degradation of GEM. To address these challenges, physicochemical and cell‐biological properties of both covalently conjugated and non‐covalently stabilized variants of GEM‐containing PG‐co‐PCL architectures have been evaluated. Self‐assembly behavior, drug loading and release capacity, cytotoxicity, and cellular uptake properties of these constructs in monolayer and in spheroid cultures of PDAC cells are investigated. To realize the covalently conjugated carrier systems, GEM, in conjunction with a tertiary amine, is attached to the polycarbonate block grafted from the PG‐co‐PCL core. It is observed that pH‐dependent ionization properties of these amine side‐chains direct the formation of self‐assembly of block copolymers in the form of nanoparticles. For non‐covalent encapsulation, a facile “solvent‐shifting” technique is adopted. Fabrication techniques are found to control colloidal and cellular properties of GEM‐loaded nanoconstructs. The feasibility and potential of these newly developed architectures for designing carrier systems for GEM to achieve augmented prognosis for pancreatic cancer are reported.
Effect of hydroxyapatite‐titanium‐MWCNTs composite coating fabricated by electrophoretic deposition on corrosion and cellular behavior of NiTi alloy
Authors: Maleki‐Ghaleh Hossein , Khalil‐Allafi Jafar
Published: June 2019

In this study, the hydroxyapatite (HA)‐titanium (Ti, 20 wt.%) multiwalled carbon nanotubes (MWCNTs, 1 wt.%) composite coating was applied on the NiTi alloy by using the electrophoretic deposition (EPD) technique. The morphologies and the phase structures of the coatings were investigated by the FESEM and XRD analysis, respectively. The corrosion behaviors of the coated NiTi samples were investigated using the polarization and electrochemical impedance spectroscopy tests in a simulated body fluid (SBF). The amounts of the released Ni ions from the coated NiTi were studied in the SBF. The results of the electrochemical tests revealed the corrosion resistance of the NiTi coated with HA was further improved by the addition of the Ti and MWCNTs to the HA coating. The current density and corrosion resistance of the NiTi alloy changed from 2.52 μA.cm−2and 24.13 kΩ to 0.91 nA.cm−2and 5.92 MΩ after coated with the HA‐Ti‐MWCNTs composite coating. Also, the number of nickel ions released from the surface of the NiTi alloy to the SBF medium suppressed from 11.8 to 0.08 μgr.L−1, after coating with HA‐Ti‐MWCNTs. Also, the cellular proliferation in the culture medium consisting of the NiTi alloy coated with the HA‐Ti‐MWCNTs improved significantly (compared with that of the NiTi alloy) as shown no toxicity in the cell culture medium.
Insight into picophytoplankton diversity of the subarctic White Sea—The first recording of Pedinophyceae in environmental DNA
Authors: Milyutina Irina A. , Belevich Tatyana A. , Ilyash Lyudmila V. , Troitsky Aleksey V.
Published: June 2019

Operational taxonomic units 94%–95% similar to the known Pedinophyceae were found as a result of high‐through sequencing of 18S rDNA V4 amplicons of environmental DNA from the summer picophytoplankton samples from the White Sea. Partial sequence of a ribosomal operon (the 5,298 bp includes partial 18S and 28S rDNA, complete 5.8S rDNA, ITS1, and ITS2 sequences) and a partial 2,112 bp chloroplast 23S rDNA sequence White Sea Pedinophyceae was amplified from metagenomic DNA by specific primers and sequenced. A new phylotype was designated as uncultured Pedinophyceae WS. On Chlorophyta phylogenetic trees the discovered phylotype occupies a basal position in the Marsupiomonadales clade. The synapomorphic base substitutions in rRNA hairpins confirm the relationship of Pedinophyceae WS to Marsupiomonadales and its difference from known genera of the order. The obtained results extend knowledge of picophytoplankton diversity in subarctic waters.
Improvement of the gain and the axial ratio of a circular polarization microstrip antenna by using a metamaterial superstrate
Authors: Safari Dehnavi Mahboubeh , Razavi Seyyed Mohammad Javad , Mohseni Armaki Seyyed Hossien
Published: June 2019

In this article, a new design of circular polarized (CP) microstrip antenna for 2.2 GHz band applications is introduced. This compact design has achieved return loss and axial ratio lower than −10 and 3 dB, respectively. Next, a polarized insensitive metamaterial surface acting as a superstrate is proposed for improvement of the antenna characteristics. By putting the suggested double stacked meta‐surface layer over a CP microstrip antenna, the radiation pattern of antenna has been improved significantly. As a result, the antenna gain is enhanced about 4.7 dBi and simultaneously the overlap of return loss band and axial ratio band is increased about 3%. The structure is simulated in CST MICROWAVE STUDIO software and the results show reasonable conformity with the measurements.
Computational and experimental investigation of RF‐induced heating for multiple orthopedic implants
Authors: Guo Ran , Zheng Jianfeng , Wang Yu , Zeng Qi , Wang Qingyan , Yang Rui , Kainz Wolfgang , Chen Ji
Published: June 2019

Purpose

This paper investigates the RF‐induced heating for multiple adjacent orthopedic implants under MRI at 1.5T and 3T exposure. When multiple implants are closely spaced to each other, the interactions between the implants may affect the RF‐induced heating. Traditional RF‐induced heating labeling is often only applicable to configurations of an individual implant, and is not applicable for multi‐implant configurations. Therefore, the aim of this study is to evaluate the effects of multiple orthopedic implants on RF‐induced heating and to propose potential appropriate instructions for safe scanning of multi‐implantable orthopedic implants.

Methods

Typical plate and nail implants were used as examples. The effects of implant configuration, relative positions, and number of implants were investigated. Numerical simulations were conducted using full‐wave electromagnetic simulation software. Experimental measurements at 1.5 T were performed to validate the numerical results.

Results

Numerical results indicate that, due to device interaction, the RF‐induced heating of multiple medical implants can be significantly different from that of a single implant. The measured temperature rise for multiple devices could be 2.7 times larger than that of a single implant.

Conclusion

Our results confirm that RF‐induced heating of multiple implants can be quite different, and do not follow simple superposition of the results from single devices. Instructions for safe scanning of individual orthopedic devices would not be applicable to multi‐implant configurations.
Rapid framework for quantitative magnetization transfer imaging with interslice magnetization transfer and dictionary‐driven fitting approaches
Authors: Kim Jae‐Woong , Lee Sul‐Li , Choi Seung Hong , Park Sung‐Hong
Published: June 2019

Purpose

To develop a rapid framework for quantitative magnetization transfer (qMT) imaging based on the 2D interslice MT and dictionary‐driven fitting approaches.

Methods

Sequential balanced steady‐state free precession (bSSFP) scanning was performed on a whole human brain in a total of 12 conditions from six different interslice gaps and two different flip angles. To obtain qMT maps, the acquired 12 datasets were fitted to a dictionary predefined by using Bloch equation simulations based on the two‐pool MT model. The proposed qMT method was compared to the conventional qMT methods, in terms of qMT parameter maps and processing time.

Results

The proposed method yielded qMT maps similar to those of the conventional method, indicating feasibility of modulating MT saturation frequency and power with the interslice gap and flip angle. The whole‐brain qMT imaging could be completed in 8 min because of the absence of separate MT pulses. The time for processing qMT parameters was significantly reduced through the dictionary‐driven approach; it is 1000 times shorter than that without the dictionary‐driven approach and 3 times shorter than that with the spoiled gradient recalled echo‐qMT method that uses an analytical solution.

Conclusion

The proposed dictionary–driven interslice qMT imaging provides qMT maps close to those from the conventional method with significantly reduced scan time and postprocessing time, which can make qMT imaging more clinically acceptable.
Focus on the glycerophosphocholine pathway in choline phospholipid metabolism of cancer
Authors: Sonkar Kanchan , Ayyappan Vinay , Tressler Caitlin M. , Adelaja Oluwatobi , Cai Ruoqing , Cheng Menglin , Glunde Kristine
Published: June 2019

Activated choline metabolism is a hallmark of carcinogenesis and tumor progression, which leads to elevated levels of phosphocholine and glycerophosphocholine in all types of cancer tested so far. Magnetic resonance spectroscopy applications have played a key role in detecting these elevated choline phospholipid metabolites. To date, the majority of cancer‐related studies have focused on phosphocholine and the Kennedy pathway, which constitutes the biosynthesis pathway for membrane phosphatidylcholine. Fewer and more recent studies have reported on the importance of glycerophosphocholine in cancer. In this review article, we summarize the recent literature on glycerophosphocholine metabolism with respect to its cancer biology and its detection by magnetic resonance spectroscopy applications.
Free intramuscular Mg2+ concentration calculated using both 31P and 1H NMRS‐based pH in the skeletal muscle of Duchenne muscular dystrophy patients
Authors: Reyngoudt Harmen , Lopez Kolkovsky Alfredo L. , Carlier Pierre G.
Published: June 2019

Early studies have demonstrated that (total) magnesium was decreased in skeletal muscle of Duchenne muscular dystrophy (DMD) patients. Free intramuscular Mg2+ can be derived from 31P NMRS measurements. The value of free intramuscular magnesium concentration ([Mg2+]) is highly dependent on precise knowledge of intracellular pH, which is abnormally alkaline in dystrophic muscle, possibly due to an expanded interstitial space, potentially causing an underestimation of [Mg2+]. We have recently shown that intracellular pH can be derived using 1H NMRS of carnosine.

Our aim was to determine whether 31P NMRS‐based [Mg2+] is, in fact, abnormally low in DMD patients, taking advantage of the 1H NMRS‐based pH. A comparative analysis was, therefore, made between [Mg2+] values calculated with both 1H and 31P NMRS‐based approaches to determine pH in 25 DMD patients, on a 3‐T clinical NMR scanner. [Mg2+] was also assessed with 31P NMRS only in (forearm or leg) skeletal muscle of 60 DMD patients and 63 age‐matched controls. Additionally, phosphodiester levels as well as quantitative NMRI indices including water T2, fat fraction, contractile cross‐sectional area and one‐year changes were evaluated.

The main finding was that the significant difference in [Mg2+] between DMD patients and controls was preserved even when the intracellular pH determined with 1H NMRS was similar in both groups. Consequently, we observed that [Mg2+] is significantly lower in DMD patients compared with controls in the larger database where only 31P NMRS data were obtained. Significant yet weak correlations existed between [Mg2+] and PDE, water T2 and fat fraction.

We concluded that low [Mg2+] is an actual finding in DMD, whether intracellular pH is normal or alkaline, and that it is a likely consequence of membrane leakiness. The response of Mg2+ to therapeutic treatment remains to be investigated in neuromuscular disorders.

Free [Mg2+] determination with 31P NMRS is highly dependent on a precise knowledge of intracellular pH. The pH of Duchenne muscular dystrophy (DMD) patients, as determined by 31P NMRS, is abnormally alkaline. We have recently shown that intracellular pH could be determined using 1H NMRS of carnosine, and that intracellular pH was alkaline in a proportion of, but not all, DMD patients with a 31P NMRS‐based alkaline pH. Taking advantage of this 1H NMRS‐based intracellular pH, we found that free intramuscular [Mg2+] is in fact abnormally low in DMD patients.
Heterogeneously Catalysed Oxidative Dehydrogenation of Menthol in a Fixed‐Bed Reactor in the Gas Phase
Authors: Kulik Anna , Neubauer Katja , Eckelt Reinhard , Bartling Stephan , Panten Johannes , Köckritz Angela
Published: June 2019

For the first time, the oxidative dehydrogenation of (−)‐menthol to (−)‐menthone and (+)‐isomenthone in a marketable quality was carried out in a continuous gas phase reactor as a sustainable process using molecular oxygen as green oxidant and solid catalysts which do not contaminate the product mixture and which are easily to remove. The diastereomeric purity remained largely unchanged. Three types of catalysts were found to be very active and selective in the formation of menthone and isomenthone: AgSr/SiO2, CuO distributed on a basic support and RuMnCe/CeO2, where Ru, Mn and Ce exist in an oxidized state. The best overall yield of menthon/isomenthone obtained with an Ag‐based catalyst was 58 % at 64 % selectivity, with a Cu‐based catalyst 41 % at 51 % selectivity and with a Ru‐based catalyst 68 % at 73 % selectivity. Reaction conditions were widely optimized.
Low‐frequency dielectric performance of polyimide composites containing amorphous polymer‐derived SiCN ceramics
Authors: Sun Dandan , Gao Yan , Liu Jinling , Ma Baisheng , Wang Yiguang
Published: June 2019

High‐dielectric‐constant polymer‐matrix composites have potential applications as embedded capacitors. In this paper, an amorphous polymer‐derived SiCN ceramic was incorporated into a polyimide (PI) matrix by in situ polymerization for the first time. The resulting SiCN/PI composite showed good thermal stability below 500°C, with the SiCN filler being homogeneously dispersed in the PI matrix. The dielectric properties of the SiCN/PI composites were investigated over a broad frequency range (0.1‐106 Hz). The dielectric properties of the SiCN/PI composites at low frequencies revealed a weak percolation phenomenon similar to that shown by conductive/polymer composites and the calculated percolation threshold was 22.8 vol%. At SiCN loadings of 25 vol%, the SiCN/PI composites showed a high dielectric constant of 190 at 0.1 Hz, which is 57 times higher than that of pure PI (3.3). The conductivity of the 25 vol% SiCN/PI composite was as low as 8.5 × 10−10 S·cm−1. These results could be explained by the unique microstructure of the polymer‐derived SiCN ceramic, containing an amorphous Si matrix and a free carbon phase. This study revealed SiCN/PI composites as promising dielectric materials with promising applications in energy storage fields.
Influence of screw configuration and processing temperature on the properties of short glass fiber reinforced polypropylene composites
Authors: Lekube Blanca Maria , Purgleitner Bianca , Renner Karoly , Burgstaller Christoph
Published: June 2019

Short glass fiber reinforced polymers are used in many different applications due to their good property profiles. These properties are directly correlated with the fiber length present in the final composite, which can be influenced through the process. Therefore, the aim of this work was to investigate the influence of processing temperature and screw configuration in compounding on the properties of glass fiber reinforced polypropylene. On the one hand, the barrel temperature was varied between 180°C and 260°C and, on the other hand, four different screw configurations were applied using a standard temperature profile. Specimens were produced by injection molding, which were tested via mechanical characterization, density, and fiber length measurements as well as morphology through microscopical analysis. We found, that with higher barrel temperatures and screw configurations bringing lower shear into the melt the glass fiber length is preserved better, thus resulting in improved composite properties. Also the interfacial interaction is not influenced within the investigated parameters, as was checked via the application of a micromechanical model in composite strength. POLYM. ENG. SCI., 59:1552–1559 2019. © 2019 Society of Plastics Engineers
Conjugated random terpolymers based on benzodithiophene, diketopyrrolopyrrole, and 8,10‐bis(thiophen‐2‐yl)‐2,5‐di(nonadecan‐3‐yl)bis[1,3]thiazolo[4,5‐f:5′,4′‐h]thieno[3,4‐b]quinoxaline for Efficient Polymer Solar Cell
Authors: Keshtov Mukhamed L. , Kuklin Sergei A. , Konstantinov Igor O. , Ostapov Ilya E. , Godovsky Dmitrii Y. , Makhaeva Elena E. , Xie Zhiyuan , Sharma Ganesh D.
Published: June 2019

A series of novel donor–acceptor (D–A) random conjugated terpolymers P2‐P4 along with the homopolymers P1 (BDT‐DPP) and P5 (BDT‐BTDQ) were designed and synthesized by copolymerizing a benzo[1,2‐b:4,5‐b]dithiophene (BDT) donor with an electron‐deficient diketopyrrolo[3,4‐c]pyrrole (DPP) unit and a benzothiadiazolo[3,4‐e]quinoxaline (BTDQ) moieties of different electron‐withdrawing strengths, and the resultant terpolymers showed broad absorption profile ranging from 300 to 1200 nm. The HOMO levels of the polymers were adjusted from −5.23 to −5.11 eV, and the optical bandgaps were controlled from 1.32 to 1.13 eV by changing the molar ratio of DPP and BTDQ acceptors. These terpolymers were used as a donor along with PC71BM as an acceptor for the creation of polymer solar cells, and the performance was optimized via variable the donor to acceptor ratio and solvent vapor annealing. The polymer solar cells made from the random terpolymer P3 showed the highest overall power conversion efficiency of (9.27%), which is higher than that for the corresponding homo‐polymers counterparts, that is, P1 (7.27%) and P5 (7.68%). The results demonstrate that the designing of random D‐A1‐D‐A2 terpolymers may be the best approach for efficient polymer solar cells. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1478–1485
Inkjet‐ and FlexTrail‐Printing with Low Silver Consumption for Silicon Heterojunction Solar Cells
Authors: Schube Jörg , Fellmeth Tobias , Jahn Mike , Keding Roman , Glunz Stefan W.
Published: June 2019

Bifacial busbarless silicon heterojunction (SHJ) solar cells with an edge length of 156.8 mm are metalized using a commercially available Ag nanoparticle ink on the front side. By means of inkjet‐printing, a maximum conversion efficiency of 23.3% is achieved. The influence of the inkjet‐printed layer number per contact finger, which is varied from one to five, on cell performance is investigated in detail. Optima are found for one and two layers, which ensure both high efficiency and low silver consumption. Furthermore, a novel metallization technology, called FlexTrail‐printing, is introduced. Using the same ink as in the case of inkjet‐printing, the finger width is reduced from 75 ± 1 to 16 ± 1 μm. This results in an enhanced short‐circuit current density and, therefore, a maximum conversion efficiency of 23.7%. Only 0.3 ± 0.1 mg Ag nanoparticle ink (deposited at 25 °C substrate temperature) is consumed during FlexTrail‐printing on a large‐area wafer (area of 244.3 cm2) with a front grid of 80 fingers.
Shelf life extension of refrigerated breaded hake medallions packed into active edible fish gelatin films
Authors: Neira Laura M. , Agustinelli Silvina P. , Ruseckaite Roxana A. , Martucci Josefa F.
Published: June 2019

Fish consumption has increased in recent years. However, fish meat is highly perishable, which demonstrates the need for technologies to preserve its quality. Edible films might provide an alternative to extend the shelf life of fish. The goal of this study was to evaluate the efficiency of edible fish gelatin films added with carvacrol (blended: FG‐0.6CRV and grafted: FG/CRV‐g‐FG) on the quality retention of commercially available prefried breaded hake medallions (BHMs). Samples of BHM were wrapped into films, heat sealed, and stored at −4 ± 1 °C for 49 days. Free carvacrol gelatin films and the unwrapped medallions were used as controls. After predetermined periods of time, samples were analysed in terms of microbiological and physicochemical properties. Overall the storage period, the total volatile basic nitrogen value (TVBN) and the total psychrotrophic bacteria counts (TPC) were significantly lesser in BHM wrapped in FG‐0.6CRV than in the other samples. The total oxidation index (TOI), peroxide value (PV), and p‐anisidine value (AV) were reduced by 18%, 30%, and 16%, respectively, compared with controls. FG/CRV‐g‐FG film was not efficient to reduce the microbial spoilage or the oxidation, probably due to the retention of CRV into the matrix avoiding its migration towards the foodstuff, proving the importance of checking the films functionality in real food systems. Sensory evaluation of fried samples wrapped in FG‐0.6CRV was also performed. The results indicate that the medallions can be directly cooked and consumed without removing the packaging with a good acceptance by the consumer.
Bit rate conditions to stabilize an uncertain scalar continuous‐time linear system with clock offset
Authors: Ling Qiang , Chen Rui , Dou Rundong
Published: June 2019

This paper aims to stabilize a scalar continuous‐time linear system that transmits its feedback information through a digital communication network. The finite bit rate of the feedback network plays a critical role in the input‐to‐state stability of that system. Stabilizing bit rate conditions depend on not only the system matrix but also the uncertainty of the system matrix and the unknown clock offset between the transmitter (sensor) and the receiver (controller). Compared with the current literature, this paper can handle the system matrix uncertainty and clock offset through implementing an event‐triggered sampling strategy and derive stabilizing conditions that require lower bit rates than those of periodic sampling strategies. Such bit rate saving mainly comes from the fact that our event‐triggered strategy can extract state information from the receive time instants of feedback packets without any extra communication cost. Simulations are done to confirm the effectiveness of the obtained stabilizing bit rate conditions.