bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heterochromatin Positioning and Nuclear Architecture
Authors: Vanrobays Emmanuel , Thomas Mélanie , Tatout Christophe 
Published: May 2017

AbstractHeitz (1928) first described the two states of chromatin known aseuchromatinandheterochromatin. Heterochromatin is often described as the gene‐poor part of the genome associated with a silent and condensed state of chromatin inaccessible to transcription factors. However, this simple view has been challenged many times as heterochromatin is indeed transcribed and differences between the two states of chromatin depend on many other criteria. Data collected from the model speciesArabidopsis thalianaindicate that heterochromatin relies on the repetitiveness of specific DNA sequences such as satellites, transposable elements and ribosomal DNA (rDNA) but also on epigenetic marks specifically associated with these repeated arrays. Recent studies on small RNA pathways have highlighted the central role of the RNA‐directed DNA methylation pathway in heterochromatin specification indicating that heterochromatin is indeed an epigenetic state required for many other genome functions including chromosome segregation, gene regulation or maintenance of genome stability. Heterochromatin is a specific feature of eukaryotes and preferential localization at the nuclear periphery and to the nucleolus is observed in most organisms. This spatial organization of heterochromatin is maintained through the cell cycle although DNA is replicated, chromatin is condensed into chromosomes, and the nuclear envelope is disrupted and reformed. Whether spatial positioning participates in heterochromatin function and how plant cells are able to establish and maintain such a genome organization across the cell cycle is still largely unknown inArabidopsis. Mechanisms leading to the appropriate positioning of heterochromatin within the nucleus will be discussed in the light of data coming from other species. A better understanding of heterochromatin organization and functions will be an important field of investigation for plants such as maize and wheat with considerably larger genome sizes thanArabidopsis.
Telomeres in Plant Meiosis: Their Structure, Dynamics and Function
Authors: Roberts Nicola Y. , Osman Kim , Franklin F. Chris H. , Pradillo Monica , Varas Javier , Santos Juan L. , Armstrong Susan J. 
Published: May 2017

AbstractAlthough the primary role of the telomeres is to protect the chromosome ends from being recognized and processed as DNA double‐strand breaks, evidence is emerging that they have a pivotal role in early events in the movement and synapsis of homologous chromosomes in the meiotic pathway. Attention has been paid to the bouquet, a nearly universal event, during which the telomeres cluster on the nuclear envelope (NE) in early prophase I. It has been suggested that their close proximity promotes homologous pairing. We have previously shown in wild‐typeArabidopsis thalianathat the telomeres are organized around the nucleolus in somatic cells and during the early stages of meiosis. While still associated with the nucleolus, homologous telomeres undergo pairing at the transition from G2 to leptotene at around the same time as assembly of the axial elements. We do not observe a classical bouquet, but as the homologues synapse during zygotene, the paired telomeres occasionally reveal a loose clustering on the NE, which may represent a transient bouquet. As Arabidopsis homologous telomere pairing precedes transient bouquet formation, we have suggested that close juxtaposition of the homologues by virtue of the tethering of the paired telomeres to the NE may facilitate subsequent chromosome alignment and synapsis. Identifying proteins that link the telomeres and the NE has been stimulated by observations inSchizosaccharomyces pombe, where meiotic telomere clustering at the spindle polar body (SPB) involves Sad1, a SPB protein that is indirectly connected to a telomere binding protein, Rap1. Sad1 and the related protein UNC‐84 fromCaenorhabditis eleganscontain a so‐called SUN domain consisting of conserved C‐terminal protein regions a few hundred amino acids long. SUN domains are usually found following a transmembrane domain and a less conserved region of amino acids. Similar proteins have subsequently been identified in other yeasts and mammalian species. In the mouse and C.elegans, they appear to be required for telomere attachment to the NE and for moving the chromosomes via the telomeres in meiosis. Several components of the NE of plants have only recently been identified. This review focuses on the structure of the telomeres in Arabidopsis and their behaviour in the meiotic pathway. We also discuss recent observations linking a role for the meiotic telomeres and their association with the NE in meiotic prophase I.
Hydrogenated TiO2 Thin Film for Accelerating Electron Transport in Highly Efficient Planar Perovskite Solar Cells
Authors: Yao Xin , Liang Junhui , Li Yuelong , Luo Jingshan , Shi Biao , Wei Changchun , Zhang Dekun , Li Baozhang , Ding Yi , Zhao Ying , Zhang Xiaodan 
Published: May 2017

AbstractIntensive studies on low‐temperature deposited electron transport materials have been performed to improve the efficiency of n‐i‐p type planar perovskite solar cells to extend their application on plastic and multijunction device architectures. Here, a TiO2 film with enhanced conductivity and tailored band edge is prepared by magnetron sputtering at room temperature by hydrogen doping (HTO), which accelerates the electron extraction from perovskite photoabsorber and reduces charge transfer resistance, resulting in an improved short circuit current density and fill factor. The HTO film with upward shifted Fermi level guarantees a smaller loss on VOC and facilitates the growth of high‐quality absorber with much larger grains and more uniform size, leading to devices with negligible hysteresis. In comparison with the pristine TiO2 prepared without hydrogen doping, the HTO‐based device exhibits a substantial performance enhancement leading to an efficiency of 19.30% and more stabilized photovoltaic performance maintaining 93% of its initial value after 300 min continuous illumination in the glove box. These properties permit the room‐temperature magnetron sputtered HTO film as a promising electron transport material for flexible and tandem perovskite solar cell in the future.
Gambling with life: Masculinity, risk, and danger in the lives of unauthorized migrant roofers
Authors: Chávez Sergio , Altman Claire E. 
Published: May 2017

BackgroundThis paper examines the occupational experiences of unauthorized immigrants employed in one of the most dangerous occupations in the United States: roofing.MethodsWe draw on 40 in‐depth interviews with return migrants in Guanajuato, Mexico, to examine how the adoption of masculinity, dangerous working conditions, the labor market structure, and absence of legal status exacerbates injuries for unauthorized roofers.FindingsUndocumented men return to Mexico injured with chronic pain, health complications, and trauma. We find that men “do gender” that is adopt masculine beliefs, when they skirt safety practices, police each other's behaviors, withhold their emotions, experience heightened stress, and engage in poor health behaviors. It is a combination of dangerous working conditions, economic insecurity, and men seeking to fulfill their masculine roles that all combine to create unsafe working conditions and lead to injuries.
Securinega Alkaloids: Complex Structures, Potent Bioactivities, and Efficient Total Syntheses
Authors: Wehlauch Robin , Gademann Karl 
Published: May 2017

AbstractThe Securinega alkaloids feature a compact tetracyclic structural framework and can be divided into four subclasses characterized by either a bridged [2.2.2]‐ or a [3.2.1]‐bicyclic core with two homologous series in each subclass. In the last two decades, many innovative strategies to chemically access the Securinega alkaloids have been developed. This Focus Review discusses the selected structures and syntheses of representative members of the Securinega alkaloids. Ring‐closing metathesis has enabled the syntheses of securinine and norsecurinine, and different cycloaddition approaches were key to the syntheses of nirurine and virosaines A and B. Virosine A was accessed through a Vilsmeier–Haack/Mannich reaction cascade. A bio‐inspired vinylogous Mannich reaction has enabled the synthesis of allosecurinine and this strategy has been extended by an intramolecular 1,6‐addition to obtain bubbialidine and secu′amamine E. A rearrangement process of the latter two alkaloids has furnished allonorsecurinine and allosecurinine, respectively. Finally, an expanded model for the biogenesis of the Securinega alkaloid subclasses is discussed.
Serum Neurofilament light: A biomarker of neuronal damage in multiple sclerosis
Authors: Disanto Giulio , Barro Christian , Benkert Pascal , Naegelin Yvonne , Schädelin Sabine , Giardiello Antonella , Zecca Chiara , Blennow Kaj , Zetterberg Henrik , Leppert David , Kappos Ludwig , Gobbi Claudio , Kuhle Jens ,   the Swiss Multiple Sclerosis Cohort Study Group
Published: May 2017

ObjectiveNeurofilament light chains (NfL) are unique to neuronal cells, are shed to the cerebrospinal fluid (CSF), and are detectable at low concentrations in peripheral blood. Various diseases causing neuronal damage have resulted in elevated CSF concentrations. We explored the value of an ultrasensitive single‐molecule array (Simoa) serum NfL (sNfL) assay in multiple sclerosis (MS).MethodssNfL levels were measured in healthy controls (HC, n = 254) and two independent MS cohorts: (1) cross‐sectional with paired serum and CSF samples (n = 142), and (2) longitudinal with repeated serum sampling (n = 246, median follow‐up = 3.1 years, interquartile range [IQR] = 2.0–4.0). We assessed their relation to concurrent clinical, imaging, and treatment parameters and to future clinical outcomes.ResultssNfL levels were higher in both MS cohorts than in HC (p < 0.001). We found a strong association between CSF NfL and sNfL (β = 0.589, p < 0.001). Patients with either brain or spinal (43.4pg/ml, IQR = 25.2–65.3) or both brain and spinal gadolinium‐enhancing lesions (62.5pg/ml, IQR = 42.7–71.4) had higher sNfL than those without (29.6pg/ml, IQR = 20.9–41.8; β = 1.461, p = 0.005 and β = 1.902, p = 0.002, respectively). sNfL was independently associated with Expanded Disability Status Scale (EDSS) assessments (β = 1.105, p < 0.001) and presence of relapses (β = 1.430, p < 0.001). sNfL levels were lower under disease‐modifying treatment (β = 0.818, p = 0.003). Patients with sNfL levels above the 80th, 90th, 95th, 97.5th, and 99th HC‐based percentiles had higher risk of relapses (97.5th percentile: incidence rate ratio = 1.94, 95% confidence interval [CI] = 1.21–3.10, p = 0.006) and EDSS worsening (97.5th percentile: OR = 2.41, 95% CI = 1.07–5.42, p = 0.034).InterpretationThese results support the value of sNfL as a sensitive and clinically meaningful blood biomarker to monitor tissue damage and the effects of therapies in MS. Ann Neurol 2017;81:857–870
Photoredox‐gesteuerte Mono‐ und Di‐Multifluorarylierung von C(sp3)‐H‐Bindungen mit Arylfluoriden
Authors: Xie Jin , Rudolph Matthias , Rominger Frank , Hashmi A. Stephen K. 
Published: May 2017

AbstractDie kontrollierbare Mono‐ und Di‐Multifluorarylierung von acyclischen und cyclischen N‐Arylaminen mit Arylfluoriden über photokatalysierte duale C(sp3)‐H/C(sp2)‐F‐Funktionalisierung eröffnet einen neuen Zugang zu einem breiten Spektrum von wertvollen α‐fluorarylierten Aminen. Auch eine sequenzielle Eintopf‐Hetero‐Di‐Multifluorarylierung von N‐Arylpyrrolidinen und N,N‐Dimethylanilinen gelang mit hoher bis ausgezeichneter Diastereoselektivität. Diese neue defluorierende C(sp3)‐C(sp2)‐Kupplung zeichnet sich durch eine große Anwendungsbreite, gute Regioselektivität und milde Bedingungen und auch eine Anwendbarkeit im Gramm‐Maßstab und auf späten Synthesestufen aus. Sie stellt damit einen signifikanten Fortschritt in der Arylierung von nichtaktivierten C(sp3)‐H‐Bindungen mit Arylfluoriden dar.
Selbstassemblierende und selbstheilende Partikelfilme zur Überwindung der Instabilität nanopartikulärer Katalysatorfilme in der alkalischen Elektrolyse
Authors: Barwe Stefan , Masa Justus , Andronescu Corina , Mei Bastian , Schuhmann Wolfgang , Ventosa Edgar 
Published: May 2017

AbstractDie Entwicklung stabiler Elektroden für die elektrochemische Wasserspaltung, insbesondere hinsichtlich der Elektrodenmodifizierung mittels Nanopartikeln, stellt immer noch eine große Herausforderung dar. Wir berichten über ein innovatives Verfahren zur Bildung hochstabiler Katalysatorfilme mit selbstheilenden Eigenschaften. Das Verfahren basiert auf sich während der Elektrolyse in situ selbstassemblierenden Nanopartikeln. Katalysatorpartikel werden zum Elektrolyten gegeben, sodass sich eine Suspension bildet, die durch die elektrochemische Zelle gepumpt wird. Partikel mit negativ geladener Oberfläche modifizieren dabei die Anode, während Partikel mit positiv geladener Oberfläche sich auf der Kathode abscheiden. Die so selbstassemblierten Katalysatorfilme weisen einen Selbstheilungseffekt auf, solange sich Katalysatorpartikel im Elektrolyt befinden. Die Funktion wurde mittels eines alkalischen Elektrolyseurs unter Verwendung von NiFe‐LDH und NixB für die Anoden‐ bzw. Kathodenseite durchgeführt. Stabile Zellspannungen konnten für Stromdichten von 50 bzw. 100 mA cm−2 über einen Zeitraum von mindestens drei Wochen beobachtet werden.
Implementation of Treat‐to‐Target in Rheumatoid Arthritis Through a Learning Collaborative: Results of a Randomized Controlled Trial
Authors: Solomon Daniel H. , Losina Elena , Lu Bing , Zak Agnes , Corrigan Cassandra , Lee Sara B. , Agosti Jenifer , Bitton Asaf , Harrold Leslie R. , Pincus Theodore , Radner Helga , Yu Zhi , Smolen Josef S. , Fraenkel Liana , Katz Jeffrey N. 
Published: May 2017

ObjectiveTreat‐to‐target (TTT) is an accepted paradigm for the management of rheumatoid arthritis (RA), but some evidence suggests poor adherence. The purpose of this study was to test the effects of a group‐based multisite improvement learning collaborative on adherence to TTT.MethodsWe conducted a cluster‐randomized quality‐improvement trial with waitlist control across 11 rheumatology sites in the US. The intervention entailed a 9‐month group‐based learning collaborative that incorporated rapid‐cycle improvement methods. A composite TTT implementation score was calculated as the percentage of 4 required items documented in the visit notes for each patient at 2 time points, as evaluated by trained staff. The mean change in the implementation score for TTT across all patients for the intervention sites was compared with that for the control sites after accounting for intracluster correlation using linear mixed models.ResultsFive sites with a total of 23 participating rheumatology providers were randomized to intervention and 6 sites with 23 participating rheumatology providers were randomized to the waitlist control. The intervention included 320 patients, and the control included 321 patients. At baseline, the mean TTT implementation score was 11% in both arms; after the 9‐month intervention, the mean TTT implementation score was 57% in the intervention group and 25% in the control group (change in score of 46% for intervention and 14% for control; P = 0.004). We did not observe excessive use of resources or excessive occurrence of adverse events in the intervention arm.ConclusionA learning collaborative resulted in substantial improvements in adherence to TTT for the management of RA. This study supports the use of an educational collaborative to improve quality.
Role of Gut Inflammation in Altering the Monocyte Compartment and Its Osteoclastogenic Potential in HLA–B27–Transgenic Rats
Authors: Ansalone Cecilia , Utriainen Lotta , Milling Simon , Goodyear Carl S. 
Published: May 2017

ObjectiveTo investigate the relationship between intestinal inflammation and the central and peripheral innate immune system in the pathogenesis of HLA–B27–associated spondyloarthritis using an HLA–B27–transgenic (B27‐Tg) rat model.MethodsThe myeloid compartment of the blood and bone marrow (BM) of B27‐Tg rats, as well as HLA–B7–Tg and non‐Tg rats as controls, was evaluated by flow cytometry. Plasma from rats was assessed by enzyme‐linked immunosorbent assay for levels of CCL2 and interleukin‐1α (IL‐1α). Rats were treated with antibiotics for 4 weeks, and the myeloid compartment of the blood and BM was evaluated by flow cytometry. The osteoclastogenic potential of BM‐derived cells from antibiotic‐treated rats, in the presence or absence of tumor necrosis factor (TNF), was evaluated in vitro.ResultsB27‐Tg rats had substantially higher numbers of circulating Lin−CD172a+CD43low monocytes as compared to control animals, and this was significantly correlated with higher levels of plasma CCL2. Antibiotic treatment of B27‐Tg rats markedly reduced the severity of ileitis, plasma levels of CCL2 and IL‐1α, and number of BM and blood Lin−CD172a+CD43low monocytes, a cell subset shown in the present study to have the greatest in vitro osteoclastogenic potential. Antibiotic treatment also prevented the TNF‐dependent enhancement of osteoclastogenesis in B27‐Tg rats.ConclusionMicrobiota‐dependent intestinal inflammation in B27‐Tg rats directly drives the systemic inflammatory and bone‐erosive potential of the monocyte compartment.
Influence of quercetin on the interaction of gliclazide with human serum albumin – spectroscopic and docking approaches
Authors: Kameníková Miroslava , Furtmüller Paul Georg , Klacsová Mária , Lopez‐Guzman Arturo , Toca‐Herrera José Luis , Vitkovská Anika , Devínsky Ferdinand , Mučaji Pavel , Nagy Milan 
Published: May 2017

AbstractProtein‐binding interactions are displacement reactions which have been implicated as the causative mechanisms in many drug–drug interactions. Thus, the aim of presented study was to analyse human serum albumin‐binding displacement interaction between two ligands, hypoglycaemic drug gliclazide and widely distributed plant flavonoid quercetin. Fluorescence analysis was used in order to investigate the effect of substances on intrinsic fluorescence of human serum albumin (HSA) and to define binding and quenching properties of ligand–albumin complexes in binary and ternary systems, respectively. Both ligands showed the ability to bind to HSA, although to a different extent. The displacement effect of one ligand from HSA by the other one has been described on the basis of the quenching curves and binding constants comparison for the binary and ternary systems. According to the fluorescence data analysis, gliclazide presents a substance with a lower binding capacity towards HSA compared with quercetin. Results also showed that the presence of quercetin hindered the interaction between HSA and gliclazide, as the binding constant for gliclazide in the ternary system was remarkably lower compared with the binary system. This finding indicates a possibility for an increase in the non‐bound fraction of gliclazide which can lead to its more significant hypoglycaemic effect. Additionally, secondary and tertiary structure conformational alterations of HSA upon binding of both ligands were investigated using synchronous fluorescence, circular dichroism and FT‐IR. Experimental data were complemented with molecular docking studies. Obtained results provide beneficial information about possible interference upon simultaneous co‐administration of the food/dietary supplement and drug.
A porphyrin‐based fluorescence method for zinc determination in commercial propolis extracts without sample pretreatment
Authors: Pierini Gastón Darío , Pinto Victor Hugo A. , Maia Clarissa G.C. , Fragoso Wallace D. , Reboucas Julio S. , Centurión María Eugenia , Pistonesi Marcelo Fabián , Di Nezio María Susana 
Published: May 2017

AbstractThe quantification of zinc in over‐the–counter drugs as commercial propolis extracts by molecular fluorescence technique using meso‐tetrakis(4‐carboxyphenyl)porphyrin (H2TCPP4) was developed for the first time. The calibration curve is linear from 6.60 to 100 nmol L−1 of Zn2+. The detection and quantification limits were 6.22 nmol L−1 and 19.0 nmol L−1, respectively. The reproducibility and repeatability calculated as the percentage variation of slopes of seven calibration curves were 6.75% and 4.61%, respectively. Commercial propolis extract samples from four Brazilian states were analyzed and the results (0.329–0.797 mg/100 mL) obtained with this method are in good agreement with that obtained with the Atomic Absorption Spectroscopy (AAS) technique. The method is simple, fast, of low cost and allows the analysis of the samples without pretreatment. Moreover the major advantage is that Zn‐porphyrin complex presents fluorescent characteristic promoting the selectivity and sensitivity of the method.
Luminescence, circular dichroism and in silico studies of binding interaction of synthesized naphthylchalcone derivatives with bovine serum albumin
Authors: Pasricha Sharda , Sharma Deepti , Ojha Himanshu , Gahlot Pragya , Pathak Mallika , Basu Mitra , Chawla Raman , Singhal Sugandha , Singh Anju , Goel Rajeev , Kukreti Shrikant , Shukla Shefali 
Published: May 2017

AbstractChalcones possess various biological properties, for example, antimicrobial, anti‐inflammatory, analgesic, antimalarial, anticancer, antiprotozoal and antitubercular activity. In this study, naphthylchalcone derivatives were synthesized and characterized using 1H NMR 13C NMR, Fourier transform infrared and mass techniques. Yields for all derivatives were found to be >90%. Protein–drug interactions influence the absorption, distribution, metabolism and excretion (ADME) properties of a drug. Therefore, to establish whether the synthesized naphthylchalcone derivatives can be used as drugs, their binding interaction toward a serum protein (bovine serum albumin) was investigated using fluorescence, circular dichroism and molecular docking techniques under physiological conditions. Fluorescence quenching of the protein in the presence of naphthylchalcone derivatives, and other derived parameters such as association constants, number of binding sites and static quenching involving confirmed non‐covalent binding interactions in the protein–ligand complex were observed. Circular dichroism clearly showed changes in the secondary structure of the protein in the presence of naphthylchalcones, indicating binding between the derivatives and the serum protein. Molecular modelling further confirmed the binding mode of naphthylchalcone derivatives in bovine serum albumin. A site‐specific molecular docking study of naphthylchalcone derivatives with serum albumin showed that binding took place primarily in the aromatic low helix and then in subdomain II. The dominance of hydrophobic, hydrophilic and hydrogen bonding was clearly visible and was responsible for stabilization of the complex.