bluuebunny/crossref_metadata_2025_split huggingface dataset:
4‐Nitrobenzoesäure [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated 4‐nitrobenzoic acid [62‐23‐7]. Available study reports and publications are described in detail. 4‐Nitro)benzoic acid caused a statistically significantly increased incidence of adenomas and of the sum of adenomas and carcinomas of the clitoris gland in female F344 rats in an oral, 2‐year carcinogenicity study at doses of 60 mg/kg body weight and day and above. The incidence of adenomas and the sum of adenomas and carcinomas was above the range limit of the historical controls of the contract laboratory. As 4‐nitrobenzoic acid is a metabolite of 4‐nitrotoluene, which also induced tumors of the clitoral gland as well as tumors in other organs, 4‐nitrobenzoic acid is classified in analogy to 4‐nitrotoluene in Carcinogen Category 3B. 4‐Nitrobenzoic acid has a weak mutagenic potency in vitro. It did not induce micronuclei in vivo or in vitro. There are no suitable data in humans to derive a MAK value. In rats, a 15‐month study and a 2‐year study resulted in a NOAEL of 60 mg/kg and day for delayed body weight gain in the females. Toxicokinetic scaling results in a concentration of 147 mg/m3in workplace air. The LOAEC for local effects on the olfactory epithelium of rats in a 14‐day study is 150 mg/m3, the NOAEC 20 mg/m3. Since 2014, the Commission uses an empirical approach to set MAK values for substances with critical effects on the upper respiratory tract or the eyes. Based on this approach, a MAK value of 1 mg/m3for the inhalable fraction was derived. The dose of 60 mg/kg body weight and day which resulted in increased incidences of clitoral gland tumors corresponds to a concentration which is about 150 times higher than the MAK value. In view of the evaluation of carcinogenicity, this margin is considered to be sufficiently large. As local effects are critical, the substance is assigned to Peak Limitation Category I. The difference between NOAEC and LOAEC is large, thus an excursion factor of 2 has been established. 4‐Nitrobenzoic acid is assigned to Pregnancy Risk Group D as the available data for prenatal toxicity are insufficient. Skin absorption does not contribute significantly to systemic toxicity and 4‐nitrobenzoic acid is not expected to lead to contact sensitization.
Diphenylamin, octyliert (Benzolamin, N‐Phenyl‐, Reaktionsprodukte mit 2,4,4‐Trimethylpenten) [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated octylated diphenylamine [
68411‐46‐1
] to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available unpublished study reports and publications are described in detail. The critical effect of octylated diphenylamine is hepatotoxicity after repeated gavage administration to rats. Octylated diphenylamine is a UVCB‐substance, a substance of unknown or variable composition, complex reaction products or biological materials. A representative composition is not known. Thus, a MAK value could not be derived and the substance is classified in Section II b of the List of MAK and BAT Values. The substance is not genotoxic. Carcinogenicity studies and data on the potential of contact sensitization in humans are not available. The substance is not a contact sensitizer in guinea pigs. Skin contact is not expected to contribute significantly to systemic toxicity.
N,N‐Bis(2‐ethylhexyl)‐((1,2,4‐triazol‐1‐yl)methyl)amin [MAK Value Documentation in German language, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: May 2017

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated N,N‐Bis(2‐ethylhexyl)‐((1,2,4‐triazol‐1‐yl)methyl)amine [
91273‐04‐0
] to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. Available unpublished study reports and publications are described in detail. N,N‐Bis(2‐ethylhexyl)‐((1,2,4‐triazol‐1‐yl)methyl)amine is corrosive to the skin of rabbits and results in irritation of the stomach after gavage administration in rats. Therefore, a local irritation potential is to be assumed. There are no inhalation studies availabe and no read‐across substance could be found. Thus, a MAK value could not be derived and the substance is classified in Section II b of the List of MAK and BAT Values. N,N‐Bis(2‐ethylhexyl)‐((1,2,4‐triazol‐1‐yl)methyl)amine is not genotoxic. Carcinogenicity studies are not available. Maximization tests in guinea pigs reveal a skin sensitizing potential and the substance is designated with „Sh“. Skin contact is not expected to contribute significantly to systemic toxicity.
Optimization Methods For Chemists and Chemometricians
Authors: Eijsbouts Corneel J.G. , Postma Geert J. , Buydens Lutgarde M. C. 
Published: May 2017

AbstractOptimization problems are abundant in analytical chemistry, while the field of computational science is bringing new optimization methods. These methods differ in strategy, sufficient for some to work very well on one optimization problem, while others are costly, inefficient, or fail at all at finding the optimum. From the chemist's point of view, it can be said that for each optimization problem there exists a suitable method to find the optimum or an acceptable solution.For problems that can be calculated with a differentiable formula, a method that uses the derivative can find the optimum probably very fast. Problems with multiple local optima are best solved with global optimizers, while for simple problems with only one optimum, a local method is more efficient. Some problems are noisy in the solution, others are too complex to optimize and are better tackled by just trying to find a really good solution instead of the best. This article provides an overview of the established classical and new nonclassical and experimental optimization techniques and highlights the mechanics of the techniques to give an understanding of which technique can be used best for the optimization problem at hand.
Charged Particle Activation Analysis: Applications
Authors: Erramli Hassane , Bounagui Omar El 
Published: May 2017

AbstractRadioactivation methods in general are essential for trace analysis because of their accuracy; among these methods, charged particle activation analysis (CPAA) is especially suitable for the determination of light elements such as boron, carbon, nitrogen, and oxygen at trace levels in materials. CPAA can also be used advantageously for other heavier elements, if needed, and sometimes be a complement to neutron activation analysis, or even competes with it.The CPAA is the best reference method because of its high sensitivity and selectivity. It permits the determination of the total concentration, regardless of the chemical state. The surface contamination can be eliminated by etching after irradiation, and absolute concentrations can be obtained by direct comparison with known compounds. There are no matrix effects and no need for reference samples.In this article, we have described and discussed, in more detail, the principle and some applications of CPAA. Examples are given of typical applications of CPAA technique such as the study of the oxygen profiling in Czochralski‐silicon (Cz‐Si) substrates submitted to a rapid thermal annealing (RTA) and the study of the oxygen behavior in thermally treated Cz‐Si by combining CPAA with ion channeling.Helium behavior in irradiated UO2is an important role in the mechanical stability of nuclear fuels during and after its use in nuclear power plants. Helium migration mechanisms in bulk uranium dioxide (UO2) have already been the subject of theoretical studies, but there is a lack of experimental data relating to the most stable location in the crystal.The question of the helium behavior in silicon carbide 6H–SiC single crystals has been studied at the atomic scale by numerical simulations, but no experiment has been carried out to assess the results hitherto. The measurements have shown that a portion of the He is located in the interstitial tetrahedral sites as predicted by the numerical simulations.
Synthesis of Dibenzo[hi,st]ovalene and Its Amplified Spontaneous Emission in a Polystyrene Matrix
Authors: Paternò Giuseppe M. , Chen Qiang , Wang Xiao‐Ye , Liu Junzhi , Motti Silvia G. , Petrozza Annamaria , Feng Xinliang , Lanzani Guglielmo , Müllen Klaus , Narita Akimitsu , Scotognella Francesco 
Published: May 2017

AbstractA large number of graphene molecules, or large polycyclic aromatic hydrocarbons (PAHs), have been synthesized and display various optoelectronic properties. Nevertheless, their potential for application in photonics has remained largely unexplored. Herein, we describe the synthesis of a highly luminescent and stable graphene molecule, namely a substituted dibenzo[hi,st]ovalene (DBO 1), with zigzag edges and elucidate its promising optical‐gain properties by means of ultrafast transient absorption spectroscopy. Upon incorporation of DBO into an inert polystyrene matrix, amplified stimulated emission can be observed with a relatively low power threshold (ca. 60 μJ cm−2), thus highlighting its high potential for lasing applications.
Chemical Recognition of Active Oxygen Species on the Surface of Oxygen Evolution Reaction Electrocatalysts
Authors: Yang Chunzhen , Fontaine Olivier , Tarascon Jean‐Marie , Grimaud Alexis 
Published: May 2017

AbstractOwing to the transient nature of the intermediates formed during the oxygen evolution reaction (OER) on the surface of transition metal oxides, their nature remains largely elusive by the means of simple techniques. The use of chemical probes is proposed, which, owing to their specific affinities towards different oxygen species, unravel the role played by these species on the OER mechanism. For that, tetraalkylammonium (TAA) cations, previously known for their surfactant properties, are introduced, which interact with the active oxygen sites and modify the hydrogen bond network on the surface of OER catalysts. Combining chemical probes with isotopic and pH‐dependent measurements, it is further demonstrated that the introduction of iron into amorphous Ni oxyhydroxide films used as model catalysts deeply modifies the proton exchange properties, and therefore the OER mechanism and activity.
A Simple Nanocellulose Coating for Self‐Cleaning upon Water Action: Molecular Design of Stable Surface Hydrophilicity
Authors: Huang Shu , Wang Dayang 
Published: May 2017

AbstractCoating solid surfaces with cellulose nanofibril (CNF) monolayers via physical deposition was found to keep the surfaces free of a variety of oils, ranging from viscous engine oil to polar n‐butanol, upon water action. The self‐cleaning function was well correlated with the unique molecular structure of the CNF, in which abundant surface carboxyl and hydroxy groups are uniformly, densely, and symmetrically arranged to form a polar corona on a crystalline nanocellulose strand. This isotropic core–corona configuration offers new and easily adoptable guidance to design self‐cleaning surfaces at the molecular level. Thanks to its excellent self‐cleaning behavior, the CNF coating converted conventional meshes into highly effective membranes for oil–water separation with no prior surface treatment required.
Hyperconjugation Is the Source of Helicity in Perfluorinatedn‐Alkanes
Authors: Cormanich Rodrigo A. , O'Hagan David , Bühl Michael 
Published: May 2017

AbstractHyperconjugative, steric, and electrostatic effects were evaluated as possible sources of the helicity in linear perfluorinated alkanes through analysis of natural bond orbitals and classical electrostatics. Contrary to previous rationalizations, which indicate dominating steric or electrostatic effects, this analysis indicates that hyperconjugative stabilization through σCC→σ*CFinteractions are the underlying driving force for the origin of the observed helicity in perfluoroalkanes.
Catalysis of Extracellular Deamination by a FAD‐Linked Oxidoreductase after Prodrug Maturation in the Biosynthesis of Saframycin A
Authors: Song Li‐Qiang , Zhang Ying‐Ying , Pu Jin‐Yue , Tang Man‐Cheng , Peng Chao , Tang Gong‐Li 
Published: May 2017

AbstractThe biosynthesis of antibiotics in bacteria is usually believed to be an intracellular process, at the end of which the matured compounds are exported outside the cells. The biosynthesis of saframycin A (SFM‐A), an antitumor antibiotic, requires a cryptic fatty acyl chain to guide the construction of a pentacyclic tetrahydroisoquinoline scaffold; however, the follow‐up deacylation and deamination steps remain unknown. Herein we demonstrate that SfmE, a membrane‐bound peptidase, hydrolyzes the fatty acyl chain to release the amino group; and SfmCy2, a secreted oxidoreductase covalently associated with FAD, subsequently performs an oxidative deamination extracellularly. These results not only fill in the missing steps of SFM‐A biosynthesis, but also reveal that a FAD‐binding oxidoreductase catalyzes an unexpected deamination reaction through an unconventional extracellular pathway in Streptmyces bacteria.
Silver(III)⋅⋅⋅Silver(III) Interactions that Stabilize the syn Form in a Porphyrin Dimer Upon Oxidation
Authors: Singh Akhil Kumar , Khan Firoz Shah Tuglak , Rath Sankar Prasad 
Published: May 2017

AbstractThe interaction between two AgII porphyrins, connected covalently through a highly flexible ethane bridge, in a metalloporphyrin dimer has been investigated upon stepwise oxidation. X‐ray structure determination of one and two‐electron oxidized complexes has clearly revealed only metal‐centered oxidation that results in short Ag−N (porphyrin) distance with large distortion in the porphyrin macrocycle. The 2e‐oxidized complex exhibits significant metallophilic interaction in the form of a close AgIII⋅⋅⋅AgIII contact that brings two porphyrin rings more cofacial with syn‐conformation, which would otherwise stabilize in an anti‐form. The interaction also leads to an intense emission peak at 546 nm at 77 K in the photoluminescence study.
Total Synthesis of Dictyodendrins by the Gold‐Catalyzed Cascade Cyclization of Conjugated Diynes with Pyrroles
Authors: Matsuoka Junpei , Matsuda Yuka , Kawada Yuiki , Oishi Shinya , Ohno Hiroaki 
Published: May 2017

AbstractIn total and formal syntheses of dictyodendrins B, C, E, and F, the key step involved the direct construction of the pyrrolo[2,3‐c]carbazole core by the gold‐catalyzed annulation of a conjugated diyne with a pyrrole to form three bonds and two aromatic rings. The subsequent introduction of substituents at the C1 (Suzuki–Miyaura coupling), C2 (addition to an aldehyde), N3 (alkylation), and C5 positions (Ullman coupling) provided divergent access to dictyodendrins.
Thermal Disproportionation of Oxo‐Functionalized Graphene
Authors: Grote Fabian , Gruber Christoph , Börrnert Felix , Kaiser Ute , Eigler Siegfried 
Published: May 2017

AbstractGraphene production by wet chemistry is an ongoing scientific challenge. Controlled oxidation of graphite introduces oxo functional groups; this material can be processed and converted back to graphene by reductive defunctionalization. Although thermal processing yields conductive carbon, a ruptured and undefined carbon lattice is produced as a consequence of CO2 formation. This thermal process is not understood, but it is believed that graphene is not accessible. Here, we thermally process oxo‐functionalized graphene (oxo‐G) with a low (4–6 %) and high degree of functionalization (50–60 %) and find on the basis of Raman spectroscopy and transmission electron microscopy performed at atomic resolution (HRTEM) that thermal processing leads predominantly to an intact carbon framework with a density of lattice defects as low as 0.8 %. We attribute this finding to reorganization effects of oxo groups. This finding holds out the prospect of thermal graphene formation from oxo‐G derivatives.
Allyl‐Palladium‐Catalyzed Ketone Dehydrogenation Enables Telescoping with Enone α,β‐Vicinal Difunctionalization
Authors: Chen Yifeng , Huang David , Zhao Yizhou , Newhouse Timothy R. 
Published: May 2017

AbstractThe telescoping of allyl‐palladium catalyzed ketone dehydrogenation with organocuprate conjugate addition chemistry allows for the introduction of aryl, heteroaryl, vinyl, acyl, methyl, and other functionalized alkyl groups chemoselectively to a wide variety of unactivated ketone compounds via their enone counterparts. The compatibility of the dehydrogenation conditions additionally allows for efficient trapping of the intermediate enolate with various electrophiles. The utility of this approach is demonstrated by comparison to several previously reported multistep sequences.
Ga(III) complex with morin for kidney cancer cell labelling
Authors: Sentkowska Aleksandra , Kilian Krzysztof , Kopeć Maciej , Pyrzyńska Krystyna , Cheda Łukasz 
Published: May 2017

The formation of a complex between Ga(III) and morin (3,5,7,2′,4′‐pentahydroxyflavone) was studied. UV–visible, infrared and mass spectroscopies were used to characterize the complex. The stoichiometric ratio for the reaction between metal ion and flavonoid was determined using the methods of Yoe–Jones and Job, which confirmed that a 1:1 Ga–morin complex was formed (estimated binding constant = 2.31 × 104 l mol−1). It was found that the coordination to Ga(III) occurs through the carbonyl oxygen atom and the 3‐OH group of the morin molecule. According to developed conditions, complexation reaction with 68Ga was performed and the complex was used to label kidney cancer cells (CAKI‐1, CAKI‐2, ACHN and 786‐O). The knowledge gained from this study should be useful for the development of new radiopharmaceuticals for diagnostic purposes containing 68Ga.
Attenuation of Follicular Helper T Cell–Dependent B Cell Hyperactivity by Abatacept Treatment in Primary Sjögren's Syndrome
Authors: Verstappen Gwenny M. , Meiners Petra M. , Corneth Odilia B. J. , Visser Annie , Arends Suzanne , Abdulahad Wayel H. , Hendriks Rudi W. , Vissink Arjan , Kroese Frans G. M. , Bootsma Hendrika 
Published: May 2017

ObjectiveTo assess the effect of abatacept (CTLA‐4Ig), which limits T cell activation, on homeostasis of CD4+ T cell subsets and T cell–dependent B cell hyperactivity in patients with primary Sjögren's syndrome (SS).MethodsFifteen patients with primary SS treated with abatacept were included. Circulating CD4+ T cell and B cell subsets were analyzed by flow cytometry at baseline, during the treatment course, and after treatment was completed. CD4+ effector T cell subsets and Treg cells were identified based on expression of CD45RA, CXCR3, CCR6, CCR4, CXCR5, programmed death 1, inducible costimulator (ICOS), and FoxP3. Serum levels of anti‐SSA/anti‐SSB and several T cell–related cytokines were measured. Expression of ICOS and interleukin‐21 (IL‐21) protein was examined in parotid gland tissue at baseline and after treatment. Changes in laboratory parameters and associations with systemic disease activity (EULAR Sjögren's Syndrome Disease Activity Index [ESSDAI]) over time were analyzed using generalized estimating equations.ResultsAbatacept selectively reduced percentages and numbers of circulating follicular helper T (Tfh) cells and Treg cells. Other CD4+ effector T cell subsets were unaffected. Furthermore, expression of the activation marker ICOS by circulating CD4+ T cells and expression of ICOS protein in parotid gland tissue declined. Reduced ICOS expression on circulating Tfh cells correlated significantly with lower ESSDAI scores during treatment. Serum levels of IL‐21, CXCL13, anti‐SSA, and anti‐SSB decreased. Among circulating B cells, plasmablasts were decreased by treatment. After cessation of treatment, all parameters gradually returned to baseline.ConclusionAbatacept treatment in patients with primary SS reduces circulating Tfh cell numbers and expression of the activation marker ICOS on T cells. Lower numbers of activated circulating Tfh cells contribute to attenuated Tfh cell–dependent B cell hyperactivity and may underlie the efficacy of abatacept.
Cost-effectiveness of high-sensitivity faecal immunochemical test and colonoscopy screening for colorectal cancer
Authors: Aronsson M , Carlsson P , Levin L-Å , Hager J , Hultcrantz R 
Published: May 2017

Abstract

Background
Colorectal cancer screening can decrease morbidity and mortality. However, there are widespread differences in the implementation of programmes and choice of strategy. The primary objective of this study was to estimate lifelong costs and health outcomes of two of the currently most preferred methods of screening for colorectal cancer: colonoscopy and sensitive faecal immunochemical test (FIT).

Methods
A cost-effectiveness analysis of colorectal cancer screening in a Swedish population was performed using a decision analysis model, based on the design of the Screening of Swedish Colons (SCREESCO) study, and data from the published literature and registries. Lifelong cost and effects of colonoscopy once, colonoscopy every 10 years, FIT twice, FIT biennially and no screening were estimated using simulations.

Results
For 1000 individuals invited to screening, it was estimated that screening once with colonoscopy yielded 49 more quality-adjusted life-years (QALYs) and a cost saving of €64 800 compared with no screening. Similarly, screening twice with FIT gave 26 more QALYs and a cost saving of €17 600. When the colonoscopic screening was repeated every tenth year, 7 additional QALYs were gained at a cost of €189 400 compared with a single colonoscopy. The additional gain with biennial FIT screening was 25 QALYs at a cost of €154 300 compared with two FITs.

Conclusion
All screening strategies were cost-effective compared with no screening. Repeated and single screening strategies with colonoscopy were more cost-effective than FIT when lifelong effects and costs were considered. However, other factors such as patient acceptability of the test and availability of human resources also have to be taken into account.