bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phthalate – Methode zur Bestimmung von Phthalaten in der Luft am Arbeitsplatz mittels Gaschromatographie‐Massenspektrometrie (GC‐MS) [Air Monitoring Methods in German language, 2017]
Authors: Nitschke L. , Breuer D. , Frenzen A. , Heinrich B. , Hebisch R. , Hartwig A. ,   MAK‐Kommission
Published: April 2017

Phthalates – Method for the determination of phthalates in workplace air using gas chromatography mass spectrometry (GC‐MS)

This analytical method is a validated measurement procedure for the determination of several phthalates such as dimethyl phthalate, diethyl phthalate, diallyl phthalate, diisobutyl phthalate, dibutyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, bis(2‐ethylhexyl) phthalate and bis(2‐propylheptyl) phthalate in workplace air. With this measure procedure airborne phthalates in the gaseous state and bound to particles are collected simultaneously. Sampling is performed by drawing a defined volume of air through a sampling system consisting of a glass fibre filter located in a GSP sampling head and an adsorption tube filled with PU foam connected downstream using a suitable pump. The flow rate is set to 1 L/min with a recommended air sample volume of 60 to 120 litres. For sample preparation the collected phthalates are desorbed from the sample carriers with 1,4‐dioxane. The sample solutions are analysed by means of gas chromatography mass spectrometry (GC‐MS). The quantitative determination is based on calibration functions obtained by means of multiple‐point calibrations. The limit of quantification for the individual phthalate lies between 0.015 and 0.096 mg/m
3
.
Addendum to Hexone (Methyl isobutyl ketone) [BAT Value Documentation 2014]
Authors: Nasterlack M. , Drexler H. , Hartwig A. ,   MAK Commission
Published: April 2017

Abstract
The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated the BAT value (biological tolerance value) for hexone (methyl isobutyl ketone, MIBK), considering methyl isobutyl ketone in urine to characterise the internal exposure.

In a field study in 36 persons, which were exposed to a mixture of toluene, xylene and MIBK, a linear relationship between MIBK in air and MIBK in urine was obtained. For the present MAK‐value of 20 ml MIBK/m
3
air a corresponding average concentration of 0.7 mg MIBK/l urine ­can be derived. In another field study 27 workers in the furniture industry were exposed to mixtures of solvents. The good linear correlation between the values determined in air and in urine permits an extrapolation to 20 ml/m
3
, which yields a corresponding concentration of 0.60 mg MIBK/l urine.

Based on these studies, a BAT value of 0.7 mg MIBK/l urine was evaluated.
Sampling is performed at the end of exposure or the end of shift.
Di(2‐propylheptyl) phthalate [MAK Value Documentation, 2015]
Authors: Hartwig A. ,   MAK Commission
Published: April 2017

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated di(2‐propylheptyl) phthalate [53306‐54‐0] considering all toxicological endpoints. Available publications and unpublished study reports are described in detail. Critical effect is the peroxisome proliferating activity in the liver which has also been observed with other phthalates. Di(2‐propylheptyl) phthalate is less potent as a peroxisome proliferator than the structurally very similar di(2‐ethylhexyl) phthalate, which is a rat liver carcinogen. No carcinogenicity study has been performed on di(2‐propylheptyl) phthalate but due to the similarity to di(2‐ethylhexyl) phthalate, liver carcinogenicity cannot be excluded. Therefore, di(2‐propylheptyl) phthalate is classified in Category 3B for suspected carcinogens. Di(2‐propylheptyl) phthalate is not genotoxic in vitro; in vivo data are missing. Only a 5‐day inhalation study has been performed. Possible long‐term effects on larynx, trachea or goblet cell hyperplasia which are target organs of di(2‐propylheptyl) phthalate and of other phthalates cannot be evaluated based on this study. No maximum concentration at the workplace (MAK value) can be derived. Di(2‐propylheptyl) phthalate shows no developmental toxicity in rats up to an oral dose of 1000 mg/kg body weight and day which is toxic to the dams. Skin contact is not expected to contribute significantly to systemic toxicity. Limited data show no sensitization.
Glycerin [MAK Value Documentation, 2016]
Authors: Hartwig A. ,   MAK Commission
Published: April 2017

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 work place (MAK value) of glycerol [
56‐81‐5
], considering the endpoints irritation of the respiratory tract and developmental toxicity.

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. However, examination of the study results showed that this approach does not apply for glycerol, because glycerol is not an eye irritant and the minimal to slight metaplasia of the squamous epithelium of the larynx seen in rats at 662 mg/m
3
with glycerol aerosol is not interpreted as adverse. The response does not increase with the exposure duration. Therefore, the MAK value is raised to 200 mg glycerol/m
3
for the inhalable fraction.

Peak Limitation Category I for local effects with an excursion factor of 2 is retained, as the effect is hardly concentration‐dependent, a sensory irritation is not known, and glycerol is, if at all, only slightly irritating to the eye.

After scaling the oral NOAELs for developmental toxicity of 1310, 1280 and 1180 mg/kg body weight and day for rats, mice, and rabbits, respectively, to a concentration at the work place (2293, 1280, and 3442 mg/m
3
), the differences to the MAK value are considered so large, that there is no reason to fear damage to the embryo or foetus when the MAK value is observed. The classification in Pregnancy Risk Group C is therefore retained.
Nickel‐Catalyzed Regioselective C–H Bond Mono‐ and Bis‐Nitration of Aryloxazolines with tert‐Butyl Nitrite as Nitro Source
Authors: Wan Li , Qiao Kai , Yuan Xin , Zheng Ming‐Wei , Fan Bing‐Bing , Di Zhe Chen , Zhang Dong , Fang Zheng , Guo Kai 
Published: April 2017

AbstractAn efficient and regioselective nickel‐catalyzed remote C–H nitration of 2‐aryloxazoline amides using the non‐corrosive tert‐butyl nitrite (TBN) as nitro source has been developed. The protocol makes use of inexpensive nickel salts as catalysts and delivers the corresponding products in excellent yields. Notably, bis‐nitration products were obtained by simply increasing the amount of tert‐butyl nitrite. This reaction proceeds in air and features excellent functional group compatibility, broad substrate scope and is suitable for gram‐scale synthesis.magnified image
Synthesis of Diarylated 4‐Pyridylmethyl Ethers via Palladium‐Catalyzed Cross‐Coupling Reactions
Authors: Ablajan Keyume , Panetti Grace B. , Yang Xiaodong , Kim Byeong‐Seon , Walsh Patrick J. 
Published: April 2017

AbstractThe direct arylation of weakly acidic sp3‐hybridized C–H bonds via deprotonated cross‐coupling processes (DCCP) is a challenge. Herein, a palladium(NIXANTPHOS)‐based catalyst for the monoarylation of 4‐pyridylmethyl 2‐aryl ethers to generate diarylated 4‐pyridyl methyl ethers is introduced. Furthermore, under similar conditions, the diarylation of 4‐pyridyl methyl ethers with aryl bromides has been developed. These methods enable the synthesis of new pyridine derivatives, which are common in medicinally active compounds and have applications in materials science.magnified image
Induced Chemical Defense of a Mushroom by a Double‐Bond‐Shifting Polyene Synthase
Authors: Brandt Philip , García‐Altares María , Nett Markus , Hertweck Christian , Hoffmeister Dirk 
Published: April 2017

AbstractThe antilarval mushroom polyenes 18‐methyl‐19‐oxoicosaoctaenoic acid and 20‐methyl‐21‐oxodocosanonaenoic acid appear in response to injury of the mycelium of the stereaceous mushroom BY1. We identified a polyketide synthase (PPS1) which belongs to a hitherto completely uncharacterized clade of polyketide synthases. Expression of the PPS1 gene is massively upregulated following mycelial damage. The synthesis of the above polyenes was reconstituted in the mold Aspergillus niger as a heterologous host. This demonstrates that PPS1 1) synchronously produces branched‐chain polyketides of varied lengths, and 2) catalyzes the unprecedented shift of eight or nine double bonds. This study represents the first characterization of a reducing polyketide synthase from a mushroom. We also show that injury‐induced de novo synthesis of polyketides is a fungal response strategy.
Synergistic effect of multiwalled carbon nanotubes and an intumescent flame retardant: Toward an ideal electromagnetic interference shielding material with excellent flame retardancy
Authors: Ma Yuying , Ma Pengfei , Ma Yujiao , Xu Dong , Wang Peifeng , Yang Rui 
Published: April 2017

ABSTRACTTo shield undesirable electromagnetic waves caused by electronic devices and simultaneously resolve the flame safety of the electronic components, an electromagnetic interference (EMI) shielding material with excellent flame‐retardant properties is urgently needed. The synergistic effect of the intumescent flame retardant (IFR) and multiwalled carbon nanotubes (MWCNTs) for polystyrene (PS) nanocomposites prepared by melt blending was investigated. The results show that addition of certain amounts of IFRs facilitated the dispersion of MWCNTs in the PS matrix, and the percolation threshold of the MWCNTs in the PS matrix also decreased from 1.67 ± 0.05 to 1.29 ± 0.04 wt %. Moreover, the EMI shielding efficiencies (SEs) of the PS–MWCNT–IFR composites were consistently higher than those of the PS–MWCNT composites without the addition of the IFRs at the same MWCNT content; this indicated that the synergistic effect of the MWCNTs and IFRs effectively improved the EMI SE of the PS–MWCNT–IFR composites. Furthermore, the limiting oxygen index (LOI) testing results show that the LOI values of the PS–MWCNT composites were consistently higher than 27%; this indicated that the PS–MWCNT composites effectively met the needs of flame safety; this indicated that the PS–MWCNT–IFR composite is a novel and promising candidate for an ideal EMI shielding material with excellent flame‐retardant properties for today's electronic devices. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45088.
Antistatic effects and mechanism of ionic liquids for methyl vinyl silicone rubber
Authors: Ye Xiwang , Guo Jianhua , Zeng Xingrong 
Published: April 2017

ABSTRACTThe effect of two ionic liquids (ILs), namely, 1‐allyl‐3‐methyl imidazolium chloride ([AMIM]Cl) and 1‐ethyl‐3‐methyl imidazolium tetrafluoroborate ([EMIM]BF4), on the surface and volume resistivities, mechanical properties, transparency, and water contact angle of methyl vinyl silicone rubber (MVQ) were investigated. The chemical structures of the two ILs before and after heat treatment were characterized by Fourier transform infrared spectroscopy. The morphology and fluorine and chlorine elemental dispersion were characterized by field emission scanning electron microscopy and energy‐dispersive X‐ray spectroscopy mapping, respectively. The antistatic mechanism was revealed. The results show that the MVQ–[EMIM]BF4 composites had lower surface and volume resistivities than the MVQ–[AMIM]Cl composites. The mechanical properties of the MVQ–[EMIM]BF4 and MVQ–[AMIM]Cl composites were slightly lower than those of the pristine MVQ. With increasing [EMIM]BF4 content, the surface and volume resistivities and water contact angle of the MVQ–[EMIM]BF4 composites decreased. When the content of [EMIM]BF4 was 2.0 phr, the MVQ–[EMIM]BF4 composites showed better antistatic performance with lower surface and volume resistivities of 9.6 × 109 Ω and 1.2 × 1011 Ω cm, respectively. The antistatic mechanism of the MVQ–IL composites was ascribed to the synergistic effect of ionic migration and moisture absorption. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45180.
Stem cell dynamics in muscle regeneration: Insights from live imaging in different animal models
Authors: Ratnayake Dhanushika , Currie Peter D. 
Published: April 2017

In recent years, live imaging has been adopted to study stem cells in their native environment at cellular resolution. In the skeletal muscle field, this has led to visualising the initial events of muscle repair in mouse, and the entire regenerative response in zebrafish. Here, we review recent discoveries in this field obtained from live imaging studies. Tracking of tissue resident stem cells, the satellite cells, following injury has captured the morphogenetic dynamics of stem/progenitor cells as they facilitate repair. Asymmetric satellite cell division generated a clonogenic progenitor pool, providing in vivo validation for this mechanism. Furthermore, there is an emerging role of stem/progenitor cell guidance at the injury site by cellular protrusions. This review concludes that live imaging is a critical tool for discovering the distinct processes that occur during regeneration, emphasising the importance of imaging in diverse animal models to capture the entire scope of stem cell functions.Also see the Video Abstract. Link to: https://youtube/tgUHSBD1N0g
Hypofractionated short‐course radiotherapy in elderly patients with glioblastoma multiforme: an analysis of the National Cancer Database
Authors: Mak Kimberley S. , Agarwal Ankit , Qureshi Muhammad M. , Truong Minh Tam 
Published: April 2017

AbstractFor elderly patients with glioblastoma multiforme (GBM), randomized trials have shown similar survival with hypofractionated short‐course radiotherapy (SCRT) compared to conventionally fractionated long‐course radiotherapy (LCRT). We evaluated the adoption of SCRT along with associated factors and survival in a national patient registry. Using the National Cancer Data Base (NCDB), we identified patients aged ≥70 years with GBM, diagnosed between 1998 and 2011, who received SCRT (34–42 Gy in 2.5–3.4 Gy fractions), or LCRT (58–63 Gy in 1.8–2.0 Gy fractions). Crude and adjusted hazard ratios (HR) were calculated using Cox regression modeling. 4598 patients were identified, 304 (6.6%) in the SCRT group and 4294 (93.4%) in the LCRT group. Median follow‐up was 8.4 months. Median age was 78 versus 75 years, respectively (P < 0.0001). Patients who received SCRT had higher Charlson–Deyo comorbidity scores versus LCRT (score of ≥2: 16.9% vs. 10.8%, respectively; P = 0.006), and were more likely to be female (53.0% vs. 44.6%, P = 0.005). Patients who received SCRT were less likely to undergo chemotherapy (42.8% vs. 79.3%, P < 0.0001), more likely to undergo biopsy only (34.5% vs. 19.5%, P < 0.0001), and more likely to receive treatment at academic/research programs (49.2% vs. 37.2%, P = 0.0001). Median survival was 4.9 months versus 8.9 months, respectively (P < 0.0001). The survival detriment with SCRT persisted on multivariable analysis [HR 1.51 (95% CI: 1.33–1.73, P < 0.0001)], adjusting for age, gender, race, comorbidities, diagnosis year, facility type, surgery, and chemotherapy. In conclusion, hypofractionated SCRT was associated with worse survival compared to conventionally fractionated LCRT for elderly patients with GBM. Patients who received SCRT were older with worse comorbidities, and were less likely to undergo chemotherapy or resection.
Boron Nitride‐supported Sub‐nanometer Pd6 Clusters for Formic Acid Decomposition: A DFT Study
Authors: Schimmenti Roberto , Cortese Remedios , Duca Dario , Mavrikakis Manos 
Published: April 2017

AbstractA periodic, self‐consistent planewave DFT study was carried out to explore the potential use of Pd6 clusters supported on a boron nitride sheet as a catalyst for the selective decomposition of formic acid (HCOOH) to CO2 and H2. The competition between formate (HCOO) and carboxyl (COOH) paths on catalytic sites, with different proximities to the support, was studied. Based on energetics alone, the reaction may mainly follow the HCOO route. Slightly lower activation energies were found at the lateral sites of the cluster as compared to top face sites. This is particularly true for the bidentate to monodentate HCOO conversion. Through comparison of results with similar studies on HCOOH decomposition on extended Pd surfaces, it was demonstrated that the existence of undercoordinated sites in the sub‐nanometer cluster could play a key role in preferentially stabilizing HCOO over COOH, which is a common CO precursor in this reaction. A hydrogen spillover mechanism was also investigated; migration toward the boron nitride support is not favorable, at least in the early stages of the reaction. However, hydrogen diffusion on the cluster has low barriers compared to those involved in formic acid decomposition.
Carbonate‐Grafted Polysilane as a New Additive for Elevated‐Temperature Lithium‐Ion Batteries
Authors: Lu Wei , Xiong Shizhao , Pu Wenjing , Xie Kai , Zheng Chunman 
Published: April 2017

AbstractNew additives are required to meet the challenge for Li‐ion batteries working at elevated temperature. Here, we report ethylene‐carbonate‐grafted polysilane (PMSVC) as an additive of commercial carbonate‐based electrolytes. PMSVC is synthesized by using graft copolymerization of ethylene carbonate onto polymethylsilane within tetrahydrofuran solvent and azodiisobutyronitrile initiator. Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy show that the substitution degree of Si−H in final product is about 5 %. Electrochemical impedance spectra and charge−discharge tests of the cell with 0.5 wt % additive show that the film on a positive electrode was mainly formed during the initial five cycles at 0.2 C. The capacity retention of the cell with additive is about 87 % after 60 cycles at 60 °C, whereas the cell with baseline electrolyte is about 80 % under the same conditions. The results suggest that the addition of PMSVC is beneficial to the cycling stability of the cell at elevated temperature. X‐ray photoelectron spectroscopy analysis identified the compounds on a cycled LiCoO2 electrode, which are associated to the degradation, oxidation‐crosslink reaction, and unreacted groups of PMSVC. The mechanism to form the protective film on positive electrode is also further discussed in this work.
C11/C9 Helical Folding in αβ Hybrid Peptides Containing 1‐Amino‐cyclohexane acetic acid (β3, 3‐Ac6c)
Authors: Wani Naiem Ahmad , Raghothama Srinivasarao , Singh Umesh Prasad , Rai Rajkishor 
Published: April 2017

AbstractThe present study describes the solid‐state conformation of αβ hybrid peptides, Boc‐Leu‐β3, 3‐Ac6c‐OH, P1; Boc‐Leu‐β3, 3‐Ac6c‐Leu‐β3, 3‐Ac6c‐OMe, P2; and Boc‐Leu‐β3, 3‐Ac6c‐Leu‐β3, 3‐Ac6c‐Leu‐OMe, P3. The dipeptide P1 adopts extended conformations, whereas tetrapeptide P2 and pentapeptide P3 favor a helical conformation stabilized by mixed types of C11/C9 intramolecular hydrogen bonds. In peptide P3, the amino group of β3, 3‐Ac6c(2) and β3, 3‐Ac6c(4) residues occupies axial orientation, whereas in P2 it occupies axial and equatorial orientations for residues β3, 3‐Ac6c(2) and β3, 3‐Ac6c(4), respectively. The self‐assembly of P3 forms channels filled with solvent molecules that present interesting patterns.
Factors screening to statistical experimental design of racemic atenolol kinetic resolution via transesterification reaction in organic solvent using free Pseudomonas fluorescens lipase
Authors: Agustian Joni , Kamaruddin Azlina Harun , Aboul‐Enein Hassan Y. 
Published: April 2017

AbstractAs the (R)‐enantiomer of racemic atenolol has no β‐blocking activity and no lack of side effects, switching from the racemate to the (S)‐atenolol is more favorable. Transesterification of racemic atenolol using free enzymes investigated as a resource to resolve the racemate via this method is limited. Screenings of enzyme, medium, and acetyl donor were conducted first to give Pseudomonas fluorescens lipase, tetrahydrofuran, and vinyl acetate. A statistical design of the experiment was then developed using Central Composite Design on some operational factors, which resulted in the conversions of 11.70–61.91% and substrate enantiomeric excess (ee) of 7.31–100%. The quadratic models are acceptable with R2 of 95.13% (conversion) and 89.63% (ee). The predicted values match the observed values reasonably well. Temperature, agitation speed, and substrate molar ratio factor have low effects on conversion and ee, but enzyme loading affects the responses highly. The interaction of temperature–agitation speed and temperature–substrate molar ratio show significant effects on conversion, while temperature–agitation speed, temperature–substrate molar ratio, and agitation speed–substrate molar ratio affect ee highly. Optimum conditions for the use of Pseudomonas fluorescens lipase, tetrahydrofuran, and vinyl acetate were found at 45°C, 175 rpm, 2000 U, and 1:3.6 substrate molar ratio.
Does Corporate Social Responsibility Put Reputation at Risk by Inviting Activist Targeting? An Empirical Test among European SMEs
Authors: Graafland Johan 
Published: April 2017

AbstractCorporate social responsibility (CSR) is believed to improve a company's reputation. However, CSR may also put reputation at risk by making the company a more attractive target for activists' campaigns. We test this effect on a sample of 1355 European small and medium‐sized enterprises (SMEs). We find that CSR increases the future probability that an SME's CSR is monitored by local non‐governmental organizations (NGOs) and that this moderates criticism of the SME's CSR. The results imply that SMEs that only halfheartedly implement CSR are more vulnerable to public criticism than SMEs that do not engage in CSR at all. It is advisable that SMEs only position themselves as sustainable companies if their environmental policies have proven to contribute to sustainable development. When initiating stakeholder engagement, SMEs should prevent disappointment by tempering stakeholders' expectations, as NGOs participating in a stakeholder dialogue can use inside information to raise public criticism. © 2017 The Authors. Corporate Social Responsibility and Environmental Management published by ERP Environment and John Wiley & Sons Ltd.
Effects of majority members' positive intergroup contact on minority members' support for ingroup rights: Mobilizing or demobilizing effects?
Authors: Kauff Mathias , Green Eva G. T. , Schmid Katharina , Hewstone Miles , Christ Oliver 
Published: April 2017

AbstractWhile some research suggests that ethnic and cultural diversity hinders societal cohesion, other studies show that it promotes intergroup contact opportunities, which, if exploited, help to overcome intergroup prejudice. Recently, however, intergroup contact theory has been criticized for neglecting the wider social context as well as for ignoring potential demobilizing contact effects for minority members. Using two cross‐sectional general population surveys (European Social Survey in 22 countries, Swiss MOSAiCH), we address these criticisms by examining whether ethnic majority members' positive contact influences ethnic minority members' support for ingroup rights at the social context level. Applying multilevel path analysis, we show that minority members are more likely to support anti‐discrimination laws and immigrant rights when living in social contexts in which majority members have positive intergroup contact experiences. Theoretical and practical implications of our findings are discussed for understanding how minority groups are affected by the climate of the social context they reside in.