bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amino Acid Functionalized Superparamagnetic Nanoparticles Inhibit Lysozyme Amyloid Fibrillization
Authors: Antosova Andrea , Bednarikova Zuzana , Koneracka Martina , Antal Iryna , Marek Jozef , Kubovcikova Martina , Zavisova Vlasta , Jurikova Alena , Gazova Zuzana 
Published: April 2019

AbstractNanoparticles have great potential to be used in various biomedical applications, including therapy or diagnosis of amyloid‐related diseases. The physical and chemical properties of iron oxide superparamagnetic nanoparticles (MNPs) functionalized with different amino acids (AAs), namely, with lysine (Lys), glycine (Gly), or tryptophan (Trp), have been characterized. The cytotoxicity of nanoparticles and their effect on amyloid fibrillization of lysozymes in vitro was also verified. The AA‐MNPs under study are nontoxic to human SHSY5Y neuroblastoma cells. Moreover, the AA‐MNPs were able to significantly inhibit lysozyme amyloid fibrillization and destroy amyloid fibrils. Kinetic studies revealed that the presence of AA‐MNPs affected lysozyme fibrillization, namely, the lag phase and steady‐state phase of the growth curves. The most effective activities were observed for Trp‐MNPs, which revealed the importance of aromatic rings in the structure of AAs used as coating agents. The obtained results indicate the possible application of these AA‐MNPs in the treatment of amyloid diseases associated with lysozyme or other amyloidogenic proteins.
Proton Transfer Accompanied by the Oxidation of Adenosine
Authors: Choi Jungkweon , Tojo Sachiko , Ahn Doo‐Sik , Fujitsuka Mamoru , Miyamoto Shunichi , Kobayashi Kazuo , Ihee Hyotcherl , Majima Tetsuro 
Published: April 2019

AbstractDespite numerous experimental and theoretical studies, the proton transfer accompanying the oxidation of 2′‐deoxyadenosine 5′‐monophosphate 2’‐deoxyadenosine 5’‐monophosphate (5’‐dAMP, A) is still under debate. To address this issue, we have investigated the oxidation of A in acidic and neutral solutions by using transient absorption (TA) and time‐resolved resonance Raman (TR3) spectroscopic methods in combination with pulse radiolysis. The steady‐state Raman signal of A was significantly affected by the solution pH, but not by the concentration of adenosine (2–50 mm). More specifically, the A in acidic and neutral solutions exists in its protonated (AH+(N1+H+)) and neutral (A) forms, respectively. On the one hand, the TA spectral changes observed at neutral pH revealed that the radical cation (A.+) generated by pulse radiolysis is rapidly converted into A.(N6−H) through the loss of an imino proton from N6. In contrast, at acidic pH (<4), AH.2+(N1+H+) generated by pulse radiolysis of AH+(N1+H+) does not undergo the deprotonation process owing to the pKa value of AH.2+(N1+H+), which is higher than the solution pH. Furthermore, the results presented in this study have demonstrated that A, AH+(N1+H+), and their radical species exist as monomers in the concentration range of 2–50 mm. Compared with the Raman bands of AH+(N1+H+), the TR3 bands of AH.2+(N1+H+) are significantly down‐shifted, indicating a decrease in the bond order of the pyrimidine and imidazole rings due to the resonance structure of AH.2+(N1+H+). Meanwhile, A.(N6−H) does not show a Raman band corresponding to the pyrimidine+NH2 scissoring vibration due to diprotonation at the N6 position. These results support the final products generated by the oxidation of adenosine in acidic and neutral solutions being AH.2+(N1+H+) and A.(N6−H), respectively.
Ethynylbenziodazolones (EBZ) as Electrophilic Alkynylation Reagents for the Highly Enantioselective Copper‐Catalyzed Oxyalkynylation of Diazo Compounds
Authors: Hari Durga Prasad , Schouwey Lionel , Barber Verity , Scopelliti Rosario , Fadaei‐Tirani Farzaneh , Waser Jerome 
Published: April 2019

AbstractEthynylbenziodoxol(on)e (EBX) cyclic hypervalent iodine reagents are now established reagents for the alkynylation of radicals and nucleophiles, yet they present limited possibilities for further structure and reactivity modification. Herein, the first synthesis is reported for the corresponding ethynylbenziodazolone (EBZ) reagents, in which the oxygen atom in the iodoheterocycle is replaced by a nitrogen atom. The substituent on the nitrogen enables further fine‐tuning of the reagent structure and reactivity. EBZ reagents are obtained easily from the corresponding benzamides by using a one‐step procedure, and display reactivity comparable to that of EBX reagents. In particular, they are applied in an asymmetric copper‐catalyzed oxyalkynylation of diazo compounds, which proceeds in high yield and enantioselectivity for a broad range of substituents on the diazo compounds and the alkyne.
Transient and Recyclable Halogenation Coupling (TRHC) for Isoflavonoid Synthesis with Site‐Selective Arylation
Authors: Wan Jie‐Ping , Tu Zhi , Wang Yuyun 
Published: April 2019

AbstractA transient and recyclable C−H iodination has been designed for the synthesis of isoflavonoids through the domino reactions of o‐hydroxyphenyl enaminones and aryl boronic acids in the presence of catalytic KI and Pd catalyst. Instead of the conventional cross‐coupling strategy employing pre‐halogenated substrates, this method transforms raw C−H bond by means of a transient C−H halogenation to smoothly relay the subsequent C‐arylation. Consequently, such a method avoids the pre‐functionalization for C−halogen bond installation as well as the generation of stoichiometric halogen‐containing waste following the cross‐coupled product, disclosing an intriguing new coupling protocol to forge the C−C bond in the virgin area between classical C−X (X=halogen) bond cross coupling and the C−H activation.
CS2 Reductive Coupling to Acetylenedithiolate by a Dinuclear Ytterbium(II) Complex
Authors: Toniolo Davide , Willauer Aurélien R. , Andrez Julie , Yang Yan , Scopelliti Rosario , Maron Laurent , Mazzanti Marinella 
Published: April 2019

AbstractThe activation of CS2 is of interest in a broad range of fields and, more particularly, in the context of creating new C−C bonds. The reaction of the dinuclear ytterbium(II) complex [Yb2L4], 1, [L=(OtBu)3SiO−] with carbon disulfide led to the isolation of unprecedented reduction products. In particular, the crystallographic characterization of complex [Yb2L4(μ‐C2S2)], 2, provided the first example of an acetylenedithiolate ligand formed from metal reduction of CS2. Computational studies indicated that this unprecedented reactivity can be ascribed to the unusual binding mode of CS22− in the isolated “key intermediate” [Yb2L4(μ‐CS2)], 3, which results from the dinuclear nature of 1.
Temporal trends in liver cancer mortality by educational attainment in the United States, 2000‐2015
Authors: Ma Jiemin , Siegel Rebecca L. , Islami Farhad , Jemal Ahmedin 
Published: April 2019

BackgroundLiver cancer is the most rapidly rising cause of cancer death in the United States. However, it is unclear whether the mortality trend differs by socioeconomic and/or hepatitis C virus (HCV) infection status.MethodsJoinpoint analyses and Poisson regression modeling were performed to examine trends in death rates from liver cancer by education and HCV infection status among persons aged 25 to 74 years from 2000 to 2015. Disparities in liver cancer mortality were measured as a relative index of inequality by education.ResultsFrom 2000 to 2015, the overall liver cancer death rate (per 100,000 persons) increased from 7.5 to 11.2 in men and from 2.8 to 3.8 in women. The increase was generally steeper in less educated groups for women and was confined to persons with ≤15 years of education for men. Consequently, the relative disparity increased until 2006 and then levelled off in women, whereas it continued to increase from 3.49 (95% CI, 3.08‐3.97) to 7.74 (95% CI, 7.13‐8.40) in men, with the increase more pronounced for HCV‐related liver cancer than HCV‐unrelated liver cancer.ConclusionsThe increases in liver cancer death rates in the United States have largely been confined to less educated persons, especially among men. Enhanced and targeted efforts are needed to halt and reverse the undue growing burden of liver cancer in lower socioeconomic groups.
Facile Synthesis of Single‐ and Multi‐Layer Graphene/Mn3O4 Integrated 3D Urchin‐Shaped Hybrid Composite Electrodes by Core‐Shell Electrospinning
Authors: Haghighi Poudeh Leila , Letofsky‐Papst Ilse , Cebeci Fevzi Çakmak , Menceloglu Yusuf , Yildiz Mehmet , Saner Okan Burcu 
Published: April 2019

AbstractThree‐dimensional (3D) urchin‐shaped free‐standing composite electrodes were produced by the integration of single‐ and multi‐layer graphene and manganese oxide in a step‐wise procedure. The strong interactions between the components were confirmed by spectroscopic characterization techniques. The influence of single‐ and multi‐layer graphene on the electrochemical performance of composite electrodes was investigated in detail. Single‐layer graphene with more oxygen functional groups showed better interfacial interactions between each component due to the exfoliated structure. The electrode containing single‐layer graphene exhibited 28% higher specific capacitance of 452 F/g at a scan rate of 1 mV/s compared to that of multi‐layer graphene. After 1000 cycles of charging‐discharging, single platelet graphene‐based electrode with a high capacitance retention of 89% showed improved synergistic effects by the combination of conductive PANI, single platelets graphene, and manganese oxide. This study indicated the importance of intercalated and exfoliated state of graphene in electrochemical behavior of supercapacitor electrodes.
Release of Formic Acid from Copper Formate: Hydride, Proton‐Coupled Electron and Hydrogen Atom Transfer All Play their Role
Authors: Pascher Tobias F. , Ončák Milan , van der Linde Christian , Beyer Martin K. 
Published: April 2019

AbstractAlthough the mechanism for the transformation of carbon dioxide to formate with copper hydride is well understood, it is not clear how formic acid is ultimately released. Herein, we show how formic acid is formed in the decomposition of the copper formate clusters Cu(II)(HCOO)3− and Cu(II)2(HCOO)5−. Infrared irradiation resonant with the antisymmetric C−O stretching mode activates the cluster, resulting in the release of formic acid and carbon dioxide. For the binary cluster, electronic structure calculations indicate that CO2 is eliminated first, through hydride transfer from formate to copper. Formic acid is released via proton‐coupled electron transfer (PCET) to a second formate ligand, evidenced by close to zero partial charge and spin density at the hydrogen atom in the transition state. Concomitantly, the two copper centers are reduced from Cu(II) to Cu(I). Depending on the detailed situation, either PCET or hydrogen atom transfer (HAT) takes place.
Generation and Analysis of Human and Murine Osteoclasts
Authors: Steffen Ulrike , Andes Fabian T. , Schett Georg 
Published: April 2019

AbstractOsteoclasts are the only bone‐resorbing cells in the body. Together with bone‐forming osteoblasts, they are responsible for bone homeostasis and constant bone remodeling. Aberrant activation of osteoclasts leads to bone loss, as seen in postmenopausal osteoporosis or in autoimmune diseases like rheumatoid arthritis. Although much research has been performed to understand and prevent osteoclast‐mediated bone loss, the mechanisms of osteoclast hyperactivation are not completely understood. This unit describes several protocols for ex vivo generation of murine and human osteoclasts, allowing study of the effects of specific cells, cytokines, or chemical substances on osteoclast formation and activity without the need for expensive and time‐consuming animal experiments. In addition, we provide protocols for specific staining of osteoclasts and for analysis of resorption activity using calcium phosphate–coated surfaces or bone slices. © 2019 by John Wiley & Sons, Inc.
A Subpopulation of Monocytes in Normal Human Blood Has Significant Magnetic Susceptibility: Quantification and Potential Implications
Authors: Kim James , Gómez‐Pastora Jenifer , Weigand Mitchell , Potgieter Marnie , A. Walters Nicole , Reátegui Eduardo , F. Palmer Andre , Yazer Mark , Zborowski Maciej , Chalmers Jeffrey J. 
Published: April 2019

AbstractThe presence of iron in circulating monocytes is well known as they play essential roles in iron recycling. Also, the storage of this metal as well as its incorrect uptake and/or release are important data to diagnose different pathologies. It has been demonstrated that iron storage in human blood cells can be measured through their magnetic behavior with high accuracy; however, the magnetic characteristics of monocytes have not been reported so far to the best of our knowledge. Therefore, in this work, we report, for the first time, the physical and magnetic properties of human monocytes, along with plasma platelets, oxyhemoglobin red blood cells (oxyHb‐RBCs), and methemoglobin red blood cells (metHb‐RBCs). The different cell populations were separated by Ficoll‐density gradient centrifugation, followed by a flow sorting step to isolate monocytes from peripheral blood mononuclear cells. The different fractions were analyzed by Coulter Counter (for determining the size distribution and concentration) and the sorted monocytes were qualitatively analyzed on ImageStream, a state‐of‐the‐art imaging cytometer. The analysis of the Coulter Counter and ImageStream data suggests that although there exists contamination in the monocyte fraction, the integrity of the sorted monocytes appears to be intact and the concentration was high enough to precisely measure their magnetic velocity by Cell Tracking Velocimetry. Surprisingly, monocytes reported the highest magnetic mobility from the four fractions under analysis, with an average magnetic velocity 7.8 times higher than MetHb‐RBCs, which is the only type of cells with positive magnetic velocities. This value is equivalent to a susceptibility 2.5 times higher than the value reported by fresh MetHb‐RBCs. It should be noted that this is the first study that reports that a subpopulation of human monocytes is much more magnetic than MetHb‐RBCs, opening the door to the possible isolation of human monocytes by label‐free magnetic techniques. Further, it is suggested that these magnetic monocytes could “contaminate” positively selected, immunomagnetically labeled blood cells (i.e., during a process using magnetically conjugated antibodies targeting cells, such as CD34 positive cells). Conversely, these magnetic monocytes could be inadvertently removed from a desired blood population when one is using a negative magnetic isolation technique to target cells for removal. © 2019 International Society for Advancement of Cytometry
Species sorting and mass effect along forest succession: Evidence from taxonomic, functional, and phylogenetic diversity of amphibian communities
Authors: Hernández‐Ordóñez Omar , Santos Bráulio A. , Pyron Robert Alexander , Arroyo‐Rodríguez Víctor , Urbina‐Cardona J. Nicolás , Martínez‐Ramos Miguel , Parra‐Olea Gabriela , Reynoso Víctor Hugo 
Published: April 2019

Abstract

Species recovery after forest disturbance is a highly studied topic in the tropics, but considerable debate remains on the role of secondary forests as biodiversity repositories, especially regarding the functional and phylogenetic dimensions of biodiversity. Also, studies generally overlook how alpha and beta diversities interact to produce gamma diversity along successional gradients.

We used a metacommunity approach to assess how species sorting (i.e., environmental filtering) and mass effect (i.e., source‐sink dynamics) affect 14 complementary metrics of amphibian taxonomic, functional, and phylogenetic diversity along a successional gradient in southern Mexico. As amphibians have narrow environmental tolerances and low dispersal capabilities, we expected that species sorting may be relatively more important than mass effect in structuring amphibian communities.

Between 2010 and 2012, we sampled frogs, salamanders, and caecilians in 23 communities distributed in four successional stages: young (2–5 years old) and intermediate (13–28 years old) secondary forests, old‐growth forest fragments, and old‐growth continuous forest. We assessed 15 ecologically relevant functional traits per species and used a time‐calibrated molecular phylogeny.

We recorded 1,672 individuals belonging to 30 species and 11 families. Supporting our expectations from the species sorting perspective, from the poorest (younger forests) to the best quality (continuous forest) scenarios, we observed (a) an increase in alpha diversity regardless of species abundances; (b) a clear taxonomic segregation across successional stages; (c) an increase in functional richness and dispersion; (d) an increase in mean phylogenetic distance and nearest taxon index; and (e) a reduction in mean nearest taxon distance. However, 10 species occurred in all successional stages, resulting in relatively low beta diversity. This supports a mass effect, where interpatch migrations contribute to prevent local extinctions and increase compositional similarity at the regional scale.

Our findings indicate that amphibian metacommunities along forest successional gradients are mainly structured by species sorting, but mass effects may also play a role if high levels of forest cover are conserved in the region. In fact, secondary forests and forest fragments can potentially safeguard different aspects of amphibian diversity, but their long‐term conservation value requires preventing additional deforestation.
Age at mating and male quality influence female patterns of reproductive investment and survival
Authors: Wilson Kerianne M. , Walker Sean E. 
Published: April 2019

AbstractThe trade‐off between the allocation of resources toward somatic maintenance or reproduction is one of the fundamentals of life history theory and predicts that females invest in offspring at the expense of their longevity or vice versa. Mate quality may also affect life history trade‐offs through mechanisms of sexual conflict; however, few studies have examined the interaction between mate quality and age at first mating in reproductive decisions. Using house crickets (Acheta domesticus), this study examines how survival and reproductive trade‐offs change based on females’ age at first reproduction and exposure to males of varying size. Females were exposed to either a large (presumably high‐quality) or small male at an early (young), middle (intermediate), or advanced (old) age, and longevity and reproductive investment were subsequently tracked. Females mated at a young age had the largest number of eggs but the shortest total lifespans while females mated at older ages produced fewer eggs but had longer total lifespans. The trade‐off between age at first mating and eggs laid appears to be mediated through higher egg‐laying rates and shorter postmating lifespans in females mated later in life. Exposure to small males resulted in shorter lifespans and higher egg‐laying rates for all females indicating that male manipulation of females, presumably through spermatophore contents, varies with male size in this species. Together, these data strongly support a trade‐off between age at first reproduction and lifespan and support the role of sexual conflict in shaping patterns of reproduction.
Performance Enhancement of Solar Cell by Incorporating Bilayer RGO‐ITO Smart Conducting Antireflection Coating
Authors: Nandi Anupam , Dhar Sukanta , Majumdar Sanhita , Saha Hiranmay , Hossain Syed Minhaz 
Published: April 2019

AbstractMultilayered graphene deposited on a flat resistive surface has twofold benefits. Less electronic scattering reduces the sheet resistance of the combined bilayer and high photon scattering through the unavoidable wrinkles on the chemically synthesized graphene layer leads to decreased effective reflection. In this paper, wet‐chemically‐synthesized reduced graphene oxide (RGO) has been employed on the top of the indium‐doped tin‐oxide (ITO) layer. The ITO layer of optimized thickness has been deposited as an alternative antireflection coating (ARC) on a p/n junction based crystalline silicon solar cell with standard textured surface. Variation in spectral response has been studied experimentally for different thickness and surface coverage of RGO on ITO. The combined effect of reduced sheet resistance due to high surface conductivity and increased photon injection efficiency due to scattering from the wrinkles of RGO results in significant improvement in the performance of the solar cell. By employing optimum thickness of RGO, percentage enhancements of about 18% and 10%, respectively, in efficiency and short‐circuit current density have been achieved over the baseline cell structure. RGO also exhibits an additional benefit as a moisture repelling layer.
Vagal schwannomas of the head and neck: A comprehensive review and a novel approach to preserving vocal cord innervation and function
Authors: Sandler Mykayla L. , Sims John R. , Sinclair Catherine , Sharif Kayvon F. , Ho Rebecca , Yue Lauren E. , Téllez Maria J. , Ulkatan Sedat , Khorsandi Azita S. , Brandwein‐Weber Margaret , Urken Mark L. 
Published: April 2019

AbstractBackgroundSchwannomas, benign tumors arising from neurolemmocytes, are the most common type of peripheral nerve tumors. Extracranial schwannomas are most often found in the parapharyngeal space, commonly involving the vagus nerve to cervical sympathetic trunk. Vagal schwannomas present several unique clinical and therapeutic challenges.MethodsA comprehensive literature review was conducted on 197 articles reporting 235 cases of cervical vagal schwannomas. Presenting symptoms, treatment approach, and postoperative outcomes were recorded and analyzed.ResultsVagal schwannomas commonly present as asymptomatic neck masses. When they become symptomatic, surgical resection is the standard of care. Gross total resection is associated with higher postoperative morbidity compared to subtotal resection. Initial reports using intraoperative nerve monitoring have shown improved nerve preservation. Recurrence rates are low.ConclusionThe combination of intermittent nerve mapping with novel continuous vagal nerve monitoring techniques may reduce postoperative morbidity and could represent the future standard of care for vagal schwannoma treatment.