bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glutarsäure [MAK Value Documentation in German language, 2019]
Authors: Hartwig A. ,   MAK Commission
Published: April 2019

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated glutaric acid [110‐94‐1] considering all toxicological endpoints. Available publications and unpublished study reports are described in detail.The critical effect is a moderate local irritation as shown with the Draize test in the rabbit eye. Inhalation studies are not available. Systemic toxicity occurs only at high doses. 500 and 1800 mg/kg body weight and day, respectively. The lowest systemic NOAEL is 250 mg/kg body weight and day for dogs, which corresponds to a concentration of 146 mg/m3at the workplace.To prevent irritation, a maximum concentration at the workplace (MAK value) of 2 mg/m3is derived for the respirable fraction by analogy with phosphoric acid and adipic acid and the substance is classified in Peak Limitation Category I with an excursion factor of 2.Glutaric acid is not genotoxic and carcinogenicity studies are not available. After toxicokinetic scaling, the NOAELs from oral developmental toxicity studies in rats and rabbits correspond to concentrations of 2275 mg/m3and 1458 mg/m3, respectively. Therefore, damage to the embryo or foetus is unlikely when the MAK value is not exceeded and glutaric acid is classified in Pregnancy Risk Group C. Skin contact is not expected to contribute significantly to systemic toxicity. Limited data show no sensitization.
Acetylaceton (2,4‐Pentandion) [MAK Value Documentation in German language, 2019]
Authors: Hartwig A. ,   MAK Commission
Published: April 2019

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) and the Pregnancy Risk Group of acetylacetone [123‐54‐6].The critical effects are haematotoxicity, neurotoxicity and irritation of the nasal mucosa. A LOAEC of 307 ml/m3for minimal effects on the blood and reduced body weight was obtained in a 14‐week inhalation study in the rat. A MAK value of 20 ml/m3had been set. This value has now been confirmed even considering the increased respiratory volume at the workplace (see List of MAK and BAT Values, Section I b and I c). As a systemic effect is critical, Peak Limitation Category II with an excursion factor of 2 has been confirmed.In spite of the low margin between the NOAEC for foetal toxicity of 53 ml/m3and the MAK value, acetylacetone had been assigned to Pregnancy Risk Group C because the incidence of unspecific foetal toxicity was very low at the LOAEC of 202 ml/m3. This classification is retained even considering the increased respiratory volume at the workplace.
1,4‐Dioxan [MAK Value Documentation in German language, 2019]
Authors: Hartwig A. ,   MAK Commission
Published: April 2019

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated 1,4‐dioxane [123‐91‐1] considering all toxicological endpoints. Available publications and unpublished study reports are described in detail.The critical effect is nasal toxicity and irritation as well as carcinogenic effects in the nose, liver, and kidneys. New carcinogenicity studies with 1,4‐dioxane in drinking water confirm the previous tumour findings in rats and mice. Squamous cell carcinomas in the rat nose, also occurring in a long‐term rat inhalation study at 1250 ml/m3, are a result of direct tissue contact with 1,4‐dioxane in the drinking water. At 50 ml/m3(LOAEC, lowest observed adverse effect level), no increase in tumour incidences, but nuclear enlargement, atrophy, and respiratory metaplasia in the nasal cavity were noted. The mechanisms involved in the tumour development in the nose are most likely cytotoxicity, inflammation, regenerative cell proliferation and hyperplasia. As the primary mode of action is non‐genotoxic and genotoxic effects play no or at most a minor part at cytotoxic doses, 1,4‐dioxane remains in Carcinogen Category 4.A NAEC of 16.67 ml/m3(LOAEC / 3) for effects in the nose was calculated from the long‐term rat inhalation study, which is in the same range as the NOAEC of 20 ml/m3from studies with 2‐ to 8‐hour inhalation exposure of volunteers. To provide additional protection from tumour induction in the nose, the MAK value is lowered to 10 ml/m3.As the critical effect of 1,4‐dioxane is local and no irritation was observed in the study with 2‐hour exposure of volunteers to 20 ml/m3, Peak Limitation Category I and the excursion factor of 2 are retained.There is an adequate margin between the NOAEC for developmental toxicity and the MAK value. Therefore, damage to the embryo or foetus is unlikely when the MAK value is not exceeded and 1,4‐dioxane remains assigned to Pregnancy Risk Group C.Because skin contact is expected to contribute significantly to systemic toxicity, the substance remains designated with “H”.Limited data do not show a sensitizing potential.
2‐Methoxypropanol‐1 [MAK Value Documentation, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: April 2019

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the maximum concentration at the workplace (MAK value) for 2‐methoxypropanol‐1 [
1589‐47‐5
]. Available publications and unpublished study reports are described in detail.

Critical effects of 2‐methoxypropanol‐1 are its irritancy and teratogenicity. A MAK value of 5 ml/m
3
had been set. By analogy with 2‐methoxypropylacetate‐1, this value is now reaffirmed.

Also, by analogy with 2‐methoxypropylacetate‐1 Peak Limitation Category I with excursion factor of 2 is set. 2‐Methoxypropanol‐1 remains assigned to Pregnancy Risk Group B and also remains designated with an “H” (for substances that can be absorbed through the skin in toxicologically relevant amounts).
Methyl styrene (vinyl toluene) (all isomers) [MAK Value Documentation, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: April 2019

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated methyl styrene [25013‐15‐4] considering all toxicological endpoints and revised the maximum concentration at the workplace (MAK value). Publications are described in detail.In long‐term inhalation studies with methyl styrene, inflammation and hyperplasia were observed in nasal tissue of rats and mice with LOAECs of 100 ml/m3and 10 ml/m3, respectively. As was shown with styrene, the reason for mice being more susceptible than rats is differences in the rates of phase I and phase II metabolism. While the rate of oxidation to the epoxide is almost the same in rats and mice, the detoxification via epoxide hydrolase and GSH‐transferase is about 10‐fold faster in rats than in mice. In human nasal tissue in vitro, oxidation of styrene is minimal but metabolization via epoxide hydrolase and GSH‐transferase occurs at almost the same rate as in rat nasal tissue. Therefore, humans are much less sensitive to nasal effects of styrene and this species difference is assumed to be the same for the similarly metabolized methyl styrene. The MAK value is derived from the LOAEC in rats and set at 20 ml methyl styrene/m3. Due to the local effect being critical, the substance is assigned to Peak Limitation Category I. As there was no sensory irritation in volunteers with methyl styrene at 50 ml/m3, the excursion factor is 2.Methyl styrene has a limited genotoxic potential only at systemically toxic doses, and 2‐year carcinogenicity studies were negative.Dermal absorption does not contribute significantly to the systemic toxicity and investigations in humans and animals do not indicate a significant sensitizing effect.Because 3 studies on the developmental toxicity of methyl styrene are only available as summaries and the reason for the differing effects cannot be evaluated, methyl styrene is assigned to Pregnancy Risk Group D.
iso‐Decyloleat [MAK Value Documentation in German language, 2019]
Authors: Hartwig A. ,   MAK Commission
Published: April 2019

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated isodecyl oleate [
59231‐34‐4
], considering all toxicological endpoints. Available publications and unpublished study reports are described in detail.

As with white mineral oil, inhalation of aerosols of the hardly water‐soluble isodecyl oleate could result in lung overload, inflammatory reactions and microgranulomas. To prevent this overload, a MAK value of 5 mg/m
3
is derived for the respirable fraction by analogy with white mineral oil and isodecyloleate is classified in Peak Limitation Category II with an excursion factor of 4.

NOAEL for developmental effects was 300 mg/kg body weight and day after oral treatment of rats, but teratogenicity was not examined and isodecyl oleate is assigned to Pregnancy Risk Group D. Isodecyl oleate is not genotoxic in bacteria. Carcinogenicity studies carried out according to the test guidelines are not available. There are no indications of a contact sensitizing potential of isodecyl oleate. Skin contact is not expected to contribute significantly to systemic toxicity.
The Giant SALR Cluster Fluid: A Review
Authors: Sweatman Martin B. , Lue Leo 
Published: April 2019

AbstractRecent developments in understanding the behavior of equilibrium fluids with competing short‐range attractions and long‐range repulsions at low concentration are reviewed. Typically, this SALR model system is used to represent solutions where at least one of the solute species interacts via a screened‐Coulomb potential, which includes many colloidal, nanoparticle, and polyelectrolyte solutions among others. Provided neither the short‐range nor long‐range interactions are too strong, and the concentration remains sufficiently low, discrete spherical clusters of solute are expected, here called “Giant SALR clusters.” Because these clusters can themselves be disordered, as though fluid particles with a renormalized interaction, such cluster fluids cannot be treated using standard mean field methods. This review therefore focuses on theoretical routes that aim to overcome this difficulty. The main outcomes of these theories are highlighted and their application to soft matter and especially biology, including complex coacervates, membraneless organelles, and the origin of life is discussed.
A gradient of pollination specialization in three species of Bolivian Centropogon
Authors: Lagomarsino Laura P. , Muchhala Nathan 
Published: April 2019

PremiseClosely related plant species with overlapping ranges often experience competition for pollination services. Such competition can select for divergence in floral traits that attract pollinators or determine pollen placement. While most species in Centropogon (Campanulaceae: Lobelioideae) have flowers that suggest adaptation to bat or hummingbird pollination, actual pollinators are rarely documented, and a few species have a mix of traits from both pollination syndromes. We studied the pollination biology of a “mixed‐syndrome” species and its co‐occurring congeners to examine the relationship between floral traits and visitation patterns for Centropogon.MethodsFieldwork at two sites in Bolivian cloud forests involved filming floral visitors, quantifying pollen transfer, and measuring floral traits. Stamen exsertion, which determines pollen placement, was measured from herbarium specimens across the geographic range of these species to test for character displacement.ResultsResults show a generalization gradient, from primarily bat pollination in white‐flowered Centropogon incanus, to bat pollination with secondary hummingbird pollination in the cream‐flowered C. brittonianus, to equal reliance on both pollinators in the red‐flowered, mixed‐syndrome C. mandonis. Pollen transfer between these species is further reduced by differences in stamen exsertion that are accentuated in zones of sympatry, a pattern consistent with character displacement.ConclusionsOur results demonstrate that key differences in floral color and shape mediate a gradient of specialization in Bolivian Centropogon. Interspecific pollen transfer is further reduced by potential character displacement of a key trait. Broadly, our results have implications for understanding the hyper‐diversity of Andean cloud forests, in which multiple species of the same genus frequently co‐occur.
Eigenvalue assignment via uncertain state feedback controllers
Authors: Siahlooei Esmaeil , Shahzadeh Fazeli Seyed Abolfazl , Karbassi Seyed Mehdi 
Published: April 2019

AbstractIn this paper, we propose a method for eigenvalue assignment using linear control systems containing uncertain elements. Uncertain systems are systems described by state equations which depend on uncertain parameters. In this paper, uncertainty is modeled with interval numbers. The proposed method assigns prescribed eigenvalues to a state feedback control system. Also, we introduce two interval operations to be used in our method use them. Some numerical experiments are presented to illustrate the effectiveness of the proposed method.
The dual luciferase reporter system and RT‐qPCR strategies for screening of MicroRNA‐21 small‐molecule inhibitors
Authors: Hei Yuan‐Yuan , Guo Yuan‐Xu , Jiang Cong‐Shan , Wang Si , Lu She‐Min , Zhang San‐Qi 
Published: April 2019

AbstractThe therapeutic potential of microRNA‐21 (miR‐21) small‐molecule inhibitors has been of particular interest to medicinal chemists. Moreover, the development of more facile screening methods is lacking. In the present study, two potential screening strategies for miR‐21 small‐molecule inhibitor including the stem‐loop reverse transcription‐quantitative PCR and dual luciferase reporter assay system were demonstrated and discussed in detail. A pmirGLO‐miR21cswt plasmid and its two different mutants were constructed for dual luciferase reporter assay system. In addition, the sensitivity and specificity of these two methods were validated. Our results demonstrated that both strategies are decent choices for the screening of small‐molecule inhibitors for miR‐21 and possibly other miRNAs. Eventually, we applied our optimized strategy to discover and characterize several promising compounds such as azobenzene derivate A, enoxacin, and norfloxacin for their potential impact on intracellular miR‐21 concentration.
Alkene Hydrosilylation on Oxide‐Supported Pt‐Ligand Single‐Site Catalysts
Authors: Chen Linxiao , Ali Iyad S. , Sterbinsky George E. , Gamler Jocelyn T. L. , Skrabalak Sara E. , Tait Steven L. 
Published: April 2019

AbstractHeterogeneous single‐site catalysts (SSCs), widely regarded as promising next‐generation catalysts, blend the easy recovery of traditional heterogeneous catalysts with desired features of homogeneous catalysts: high fraction of active sites and uniform metal centers. We previously reported the synthesis of Pt‐ligand SSCs through a novel metal‐ligand self‐assembly method on MgO, CeO2, and Al2O3 supports (J. Catal. 2018, 365, 303–312). Here, we present their applications in the industrially‐relevant alkene hydrosilylation reaction, with 95 % yield achieved under mild conditions. As expected, they exhibit better metal utilization efficiency than traditional heterogeneous Pt catalysts. The comparison with commercial catalysts (Karstedt and Speier) reveals several advantages of these SSCs: higher selectivity, less colloidal Pt formation, less alkene isomerization/hydrogenation, and better tolerance towards functional groups in substrates. Despite some leaching, our catalysts exhibit satisfactory recyclability and the single‐site structure remains intact on oxide supports after reaction. Pt single‐sites were proved to be the main active sites rather than colloidal Pt formed during the reaction. An induction period is observed in which Pt sites are activated by Cl detachment and replacement by reactant alkenes. The most active species likely involves temporary detachment of Pt from ligand or support. Catalytic performance of Pt SSCs is sensitive to the ligand and support choices, enabling fine tuning of Pt sites. This work highlights the application of heterogeneous SSCs created by the novel metal‐ligand self‐assembly strategy in an industrially‐relevant reaction. It also offers a potential catalyst for future industrial hydrosilylation applications with several improvements over current commercial catalysts.
Active Anchoring Polysulfides of ZnS‐Decorated Porous Carbon Aerogel for a High‐Performance Lithium‐Sulfur Battery
Authors: Hua Yang , Li Xueliang , Zhang Xingchi , Zhang Luyao , Shu Yizhen , Sheng Huijuan , Fang Huagao , Wei Haibing , Ding Yunsheng 
Published: April 2019

AbstractA carbon aerogel composite modified with ZnS (ZnS‐CA) was successfully prepared through a simple in situ synthesis and used as a cathode for lithium‐sulfur batteries. The nanopore ZnS‐CA composites with a high specific surface area and rich mesoporous structure exhibit stronger adsorption and immobilization ability for polysulfides. The ZnS‐CA/S cathode materials offer excellent electrochemical performances with lasting cycling stability and high specific capacity. In particular, the 6ZnS‐CA/S sample achieves an initial capacity of 1352 mAh g−1 at 0.2 C and maintains a high capacity of 1119 mAh g−1 after 100 cycles. Furthermore, after 300 long cycles, it still maintains a high capacity of 730 mAh g−1 at 1 C. These excellent performance features are attributed to the strong affinity of ZnS for Li2Sn species, thus polysulfide shuttling can be effectively inhibited from the cathode source. Furthermore, the strong adsorption energy between ZnS and polysulfides was validated by using first‐principles theory calculations, which reveals the anchoring and catalytic mechanism.
Metallbäumchen im Mikromaßstab
Authors: Kranz Dorothee , Brunßen Kathrin , Kirch Sandra , Babicz Heiko , Merz Rolf , Schmitt Oliver , Noll Angelika , Schygulla Jennifer , Stieger Eduard , Sitzmann Helmut 
Published: April 2019

ZusammenfassungBei der reduktiven Abscheidung von 18 Metallen und einem Halbleiter an weniger edlen Metallen oder an einer Kathode durch Elektrolyse wurden charakteristische, eigentümliche und bisweilen bizarre Formen beobachtet. Besonders nachdenklich machten wirbelnde Salzkriställchen, Kupferstreifen auf Silberbäumen und Umwandlungen von goldhaltigen Niederschlägen. Besonders empfehlenswerte Metallbäumchen‐Versuche für den Schulunterricht sind außer den etablierten Favoriten Kupfer und Silber noch Zinn und Bismut wegen der Form und Dynamik ihres Wachstums, der Unbedenklichkeit, des günstigen Preises und deren Lage zwischen Kupfer und Zink in der Spannungsreihe der Metalle. Besonders genossen haben wir die Experimente mit jedem Tropfen Tetrachloridogold(III)säure, die sehr ergiebig ist und nicht so teuer wie der Ruf des Goldes.
Neurotrition – wie Lebensmittel auf die Gehirnfunktion wirken
Authors: Sahin Sümeyye , Büttner Andrea , Pischetsrieder Monika 
Published: April 2019

ZusammenfassungIm Bereich der molekularen Ernährungsphysiologie beschäftigen sich Lebensmittelchemiker mit der Frage, welche Wirkungen Lebensmittelinhaltsstoffe auf spezifische Körperfunktionen ausüben. Ziel ist es dabei vor allem, die physiologische Aktivität einer molekular definierten Verbindung zuzuordnen. Einen wichtigen Teilbereich der molekularen Ernährungsphysiologie stellt die Sensorik dar, bei der Lebensmittelinhaltsstoffe näher untersucht werden, die Aroma, Geschmack, Textur, und andere chemosensorische Reize von Lebensmitteln bestimmen. In dem Artikel werden die molekulare Ernährungslehre und Sensorik an verschiedenen Beispielen aus der aktuellen Forschung dargestellt. So wird beschrieben, dass Eugenol und Acetyleugenol aus Nelkenextrakt über den GABAA‐Rezeptor eine sedierende Wirkung ausüben können. In diesem Zusammenhang ist es nicht nur wichtig, die Wirkung der in Lebensmitteln enthaltenen Verbindungen zu untersuchen, sondern auch deren Resorption und Biotransformation nach der Aufnahme zu berücksichtigen. Weiterhin wird dargestellt, dass bestimmte Lebensmittel, wie zum Beispiel Kartoffelchips oder Schokolade auch bei gesunden Konsumenten einen Kontrollverlust beim Essen verursachen können. Dies ist vermutlich darauf zurückzuführen, dass deren Inhaltsstoffe, vor allem ein bestimmtes Verhältnis von Kohlenhydraten und Fett, das Gehirnaktivitätsmuster deutlich verändern. Aber auch ein ausgewogenes Verhältnis der sensorisch aktiven Komponenten aus Geruch und Geschmack und anderen sensorischen Reizen steuert unsere Lebensmittelauswahl und unser Verzehrverhalten. Diese sensorischen Eindrücke werden im Lauf des Lebens für bestimmte Lebensmittel gelernt und positiv oder negativ assoziiert. Dieser Feedback‐Mechanismus kann das Verhalten des Konsumenten steuern und somit seine Lebensmittelwahl beeinflussen.
Mechanisms of action of metformin with special reference to cardiovascular protection
Authors: Zilov Alexey V. , Abdelaziz Sulaf Ibrahim , AlShammary Afaf , Al Zahrani Ali , Amir Ashraf , Assaad Khalil Samir Helmy , Brand Kerstin , Elkafrawy Nabil , Hassoun Ahmed A.K. , Jahed Adel , Jarrah Nadim , Mrabeti Sanaa , Paruk Imran 
Published: April 2019

SummaryManagement guidelines continue to identify metformin as initial pharmacologic antidiabetic therapy of choice for people with type 2 diabetes without contraindications, despite recent randomized trials that have demonstrated significant improvements in cardiovascular outcomes with newer classes of antidiabetic therapies. The purpose of this review is to summarize the current state of knowledge of metformin's therapeutic actions on blood glucose and cardiovascular clinical evidence and to consider the mechanisms that underlie them. The effects of metformin on glycaemia occur mainly in the liver, but metformin‐stimulated glucose disposal by the gut has emerged as an increasingly import site of action of metformin. Additionally, metformin induces increased secretion of GLP‐1 from intestinal L‐cells. Clinical cardiovascular protection with metformin is supported by three randomized outcomes trials (in newly diagnosed and late stage insulin‐treated type 2 diabetes patients) and a wealth of observational data. Initial evidence suggests that cotreatment with metformin may enhance the impact of newer incretin‐based therapies on cardiovascular outcomes, an important observation as metformin can be combined with any other antidiabetic agent. Multiple potential mechanisms support the concept of cardiovascular protection with metformin beyond those provided by reduced blood glucose, including weight loss, improvements in haemostatic function, reduced inflammation, and oxidative stress, and inhibition of key steps in the process of atherosclerosis. Accordingly, metformin remains well placed to support improvements in cardiovascular outcomes, from diagnosis and throughout the course of type 2 diabetes, even in this new age of improved outcomes in type 2 diabetes.