bluuebunny/crossref_metadata_2025_split huggingface dataset:
Methyl acetate [MAK Value Documentation, 2016]
Authors: Hartwig A. ,   MAK Commission
Published: October 2018

AbstractThe 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 methyl acetate [79‐20‐9] of 100 ml/m3considering the critical endpoint respiratory tract irritation. A 28‐day study with rats shows a NOAEC for degeneration and necrosis of the olfactory epithelium of 350 ml/m3. A chronic NAEC of 125 to 167 ml/m3can be extrapolated. 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. According to this approach, the NAEC would correspond to a concentration of 63 to 84 ml/m3for work place air. However, acetic acid resulting from the local enzymatic cleavage of methyl acetate by carboxylesterases is responsible for the effects to the olfactory epithelium, and not the substance itself. Thus, the activity of rat and human carboxylesterases is decisive in the respiratory tract irritation of methyl acetate. Based on a comparative analysis on vinyl acetate, in which rat olfactory enzyme activity was shown to be almost equivalent to that in humans, the same is assumed for methyl acetate and the interspecies extrapolation step is deemed unnecessary. The MAK value is retained at 100 ml/m3. As local effects are critical, the assignment to Peak Limitation Category I and the excursion factor of 4 are also retained.
White mineral oil, pharmaceutical [MAK Value Documentation, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: October 2018

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) and the Pregnancy Risk Group of pharmaceutical white mineral oil [
8042‐47‐5
].

Critical effect is lung toxicity which is observed as microgranulomas in two long‐term studies with rats and dogs at a respirable aerosol concentration of 100 mg/m
3
with a NOAEC of 5 mg/m
3
. A MAK value of 5 mg/m
3
had been set as the respirable fraction (R). This value is now reaffirmed even considering the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c).

Pharmaceutical white mineral oil had been classified in Pregnancy Risk Group C because the NOAEC for developmental toxicity is 1000 mg/m
3
in rats. There is no new data on developmental toxicity. This classification is retained even considering the increased respiratory volume at the workplace.
N
‐Vinyl‐2‐pyrrolidone [MAK Value Documentation, 2014]
Authors: Hartwig A. ,   MAK Commission
Published: October 2018

Abstract

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated
N
‐vinyl‐2‐pyrrolidone [
88‐12‐0
], considering all toxicological endpoints. Available publications and unpublished study reports are described in detail.

The main critical effects are the carcinogenic effects in the liver, nose and larynx after inhalation, with cell proliferation in the liver and degeneration and hyperplasia in the nasal epithelium starting at 0.5 ml/m
3
being the most sensitive endpoints. The no observed adverse effect concentration (NOAEC) for both organs is 0.2 ml/m
3
. As a NOAEC was obtained and the substance is not genotoxic,
N
‐vinyl‐2‐pyrrolidone is classified in Carcinogen Category 4.

As the NOAEC of 0.2 ml/m
3
for cell proliferation in the liver after 28 days was lower than that after 7 days, a MAK value for
N
‐vinyl‐2‐pyrrolidone of 0.02 ml/m
3
has been established, taking into account the short study duration. As the MAK value is derived from a systemic effect, the substance is classified in Peak Limitation Category II with the default excursion factor of 2, because the half‐life in humans is not known.

In a developmental toxicity study in rats,
N
‐vinyl‐2‐pyrrolidone at 20 ml/m
3
markedly reduced body weights in dams and foetuses and increased the incidence of variations in foetuses. As developmental toxicity occurred at a maternally toxic concentration, and the 250‐fold difference between the NOAEC for developmental toxicity of 5 ml/m
3
and the MAK value of 0.02 ml/m
3
is sufficiently large,
N
‐vinyl‐2‐pyrrolidone is classified in Pregnancy Risk Group C.

N
‐Vinyl‐2‐pyrrolidone is neither mutagenic nor clastogenic and therefore not classified in one of the categories for germ cell mutagens.

As the amount calculated to be absorbed through the skin is far above the amount absorbed daily by exposure at the level of the MAK value,
N
‐vinyl‐2‐pyrrolidone is designated with an “H” (for substances that can be absorbed through the skin in systemically toxic amounts).

The substance is not regarded as a sensitizer, because there are no corresponding clinical findings in humans and a Buehler test in guinea pigs was negative.
Decahydronaphthalene [MAK Value Documentation, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: October 2018

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 decahydronaphthalene [
91‐17‐8
].

Critical effect is kidney toxicity which is observed as increased activity of urinary lactate dehydrogenase (LDH) in a 14‐week inhalation study with rats beginning at the lowest concentration of 25 ml/m
3
with a lower confidence limit of the benchmark dose (BMDL) of 12 ml/m
3
. A MAK value of 5 ml/m
3
has been set. This value is now reaffirmed even considering the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c).

As there is no new data, Peak Limitation Category II with excursion factor of 2 is retained and decahydronaphthalene remains assigned to Pregnancy Risk Group D.
Isopropyl benzene (Cumene) [MAK Value Documentation, 2018]
Authors: Hartwig A. ,   MAK Commission
Published: October 2018

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 isopropyl benzene [
98‐82‐8
].

Critical effects after repeated inhalation exposure to isopropyl benzene are the induction of tumours in the lung of mice and in the nose of rats as well as effects on the liver in these species. The classification of isopropyl benzene in Category 3 B for carcinogenic substances is retained. Based on the increased liver weight in a 14‐week inhalation study with rats, a MAK value of 10 ml/m
3
has been set. This value is now reaffirmed even considering the increased respiratory volume at the workplace (see List of MAK and BAT Values, Sections I b and I c). As there was a change in the Commissions evaluation on the adversity of increased liver weight, the new evaluation is based on the lower confidence limit of the benchmark dose (BMDL) of 42 ml/m
3
for nasal adenoma in male rats in a two‐year inhalation study.

As there is no new data, Peak Limitation Category II with excursion factor of 4 is retained and isopropyl benzene remains assigned to Pregnancy Risk Group C. Isopropyl benzene also remains designated with an “H” (for substances that can be absorbed through the skin in toxicologically relevant amounts).
Nitrobenzene [MAK Value Documentation, 2017]
Authors: Hartwig A. ,   MAK Commission
Published: October 2018

AbstractThe German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has re‐evaluated carcinogenicity of nitrobenzene [98‐95‐3], considering all endpoints. Available publications and unpublished study reports are described in detail.The genotoxic potential of nitrobenzene is low and might be a result of reactive oxygen species. Long‐term studies with exposure by inhalation resulted in a significant increase in liver and kidney adenomas in rats, and lung and mammary adenomas in mice. In severely toxic concentrations a nonsignificant increase in carcinomas was observed, probably resulting from a chronic toxic mechanism, supported by secondary genotoxic or DNA‐damaging effects at high doses. In view of other aromatic amines and the known mechanisms of action via phenylhydroxylamine, nitrobenzene is considered to be carcinogenic. Because of the non‐linear dose‐response relationship of the tumour incidences and as genotoxic effects play a minor part, nitrobenzene is classified in Carcinogen Category 4.Eye and skin irritation from nitrobenzene is low. The critical effect is the bronchialisation in the lungs of mice in a long‐term inhalation study. However, the incidence of bronchialisation at the lowest tested concentration of 5 ml/m3is too high to calculate a NAEC. One long‐term inhalation study in Sprague‐Dawley rats resulted in a NOAEC of 1 ml/m3, another one in F344 rats showed minimal extramedullary haematopoesis in the spleen of males at the lowest tested concentration of 1 ml/m3. Using this concentration as point of departure, a MAK value of 0.1 ml/m3is calculated, which is far below the LOAEC of the critical effect in the mouse lung.As the MAK value is derived from a systemic effect, nitrobenzene is assigned to Peak Limitation Category II. Because of the initial half‐life of 5 hours, the excursion factor of 4 is set.Skin contact may contribute significantly to systemic toxicity; therefore, the “H” notation is retained.Damage to the embryo or foetus is unlikely when the MAK value is observed and thus, the substance is classified in Pregnancy Risk Group C.Sensitization is not expected from the limited data.
Moderate Physical Activity and Prevention of Cartilage Loss in People With Knee Osteoarthritis: Data From the Osteoarthritis Initiative
Authors: Bricca Alessio , Wirth Wolfgang , Juhl Carsten B. , Kemnitz Jana , Hunter David J. , Kwoh C. Kent , Eckstein Felix , Culvenor Adam G. 
Published: October 2018

ObjectiveTo examine the impact of physical activity on cartilage thickness loss in knee osteoarthritis (OA).MethodsA total of 689 participants with radiographic knee OA at baseline (Kellgren/Lawrence grade ≥2) from the Osteoarthritis Initiative completed the Physical Activity Scale for the Elderly (PASE) questionnaires at annual intervals over 4 years. Magnetic resonance imaging–based cartilage thickness change in the medial femorotibial compartment (MFTC) over 4 years was the main outcome. The impact of PASE tertiles (low, moderate, or high) on changes in MFTC cartilage thickness was estimated using a mixed‐effects model adjusted for baseline characteristics. Furthermore, stratification by sex was performed for secondary analyses.ResultsStructural progression of MFTC cartilage loss of −0.20 mm (95% confidence interval [95% CI] −0.22, −0.17) was observed in the entire cohort, with no significant difference between physical activity levels after adjustment for baseline characteristics. An interaction between sex and physical activity was observed in the adjusted analysis (P = 0.02). Stratification by sex showed that women with low physical activity had a statistically greater cartilage loss than women with moderate physical activity (adjusted between‐group difference –0.09 mm [95% CI –0.16, 0.02]), whereas no significant differences were observed in men.ConclusionWhile physical activity was not associated with cartilage thickness loss in the whole cohort, this relationship significantly differed between sexes. In women, but not in men, moderate physical activity may slow down structural disease progression compared to low physical activity levels. For both men and women, high physical activity levels do not appear to be more detrimental than lower physical activity levels for cartilage thickness loss.
Adaptive neural control of MIMO uncertain nonlinear systems with unmodeled dynamics and output constraint
Authors: Zhang Tianping , Liu Heqing , Xia Meizhen , Yi Yang 
Published: October 2018

SummaryIn this paper, an adaptive dynamic surface control (DSC) method is investigated for a class of multiple‐input–multiple‐output block‐structure uncertain nonlinear systems with unmodeled dynamics and output constraint. Modified DSC is used to construct the vector virtual control and control strategy in recursive each step. A dynamic signal is used to handle unmodeled dynamics in the system. Radial basis function neural networks are used to estimate the unknown continuous black‐box functions. By introducing the symmetric barrier Lyapunov functions, the constraint requirement of each element in the output is guaranteed in the designed adaptive control system. Using the defined compact set in the theoretical analysis and the proof characteristics of DSC, the introduced input uncertain term is effectively deal with in the controller design. The stability analysis shows that all the signals in the closed‐loop control system are semiglobally uniformly ultimately bounded. A numerical simulation example with the two‐link flexible robotic system is provided to verify the effectiveness of the constructed control scheme.
Micropatterned Scaffolds with Immobilized Growth Factor Genes Regenerate Bone and Periodontal Ligament‐Like Tissues
Authors: Pilipchuk Sophia P. , Fretwurst Tobias , Yu Ning , Larsson Lena , Kavanagh Nolan M. , Asa'ad Farah , Cheng Kenneth C. K. , Lahann Joerg , Giannobile William V. 
Published: October 2018

AbstractPeriodontal disease destroys supporting structures of teeth. However, tissue engineering strategies offer potential to enhance regeneration. Here, the strategies of patterned topography, spatiotemporally controlled growth factor gene delivery, and cell‐based therapy to repair bone–periodontal ligament (PDL) interfaces are combined. Micropatterned scaffolds are fabricated for the ligament regions using polycaprolactone (PCL)/polylactic‐co‐glycolic acid and combined with amorphous PCL scaffolds for the bone region. Scaffolds are modified using chemical vapor deposition, followed by spatially controlled immobilization of vectors encoding either platelet‐derived growth factor‐BB or bone morphogenetic protein‐7, respectively. The scaffolds are seeded with human cells and delivered to large alveolar bone defects in athymic rats. The effects of dual and single gene delivery with and without micropatterning are assessed after 3, 6, and 9 weeks. Gene delivery results in greater bone formation at three weeks. Micropatterning results in regenerated ligamentous tissues similar to native PDL. The combination results in more mature expression of collagen III and periostin, and with elastic moduli of regenerated tissues that are statistically indistinguishable from those of native tissue, while controls are less stiff than native tissues. Thus, controlled scaffold microtopography combined with localized growth factor gene delivery improves the regeneration of periodontal bone–PDL interfaces.
Surface modification of polypropylene nonwoven fabrics by grafting of polydopamine
Authors: Chen Shichang , Zhang Lihao , Sun Menghan , Zhang Xianming , Chen Wenxing 
Published: October 2018

AbstractA nonwoven fabrics based on 3‐isopropenyl‐α,α′‐dimethylbenzene isocyanate grafting polypropylene (PP‐g‐TMI) was modified with dopamine both by covalent reaction and by polymer layer deposition involving straightforward self‐polymerization (PP‐PDA) to improve the hydrophilic property of polypropylene nonwoven fabrics. The functionalized surfaces were characterized by structural and morphological analysis combined with the rheological property to confirm the location and dispersion ofPDA. The water contact angle, water absorption ability, and the vapor transmission rate were examined to evaluate the hydrophilicity performance of modified materials. It was found that the aggregated small particles onPPnonwoven fabric could result in a heterogeneous surface, and the modifiedPPnonwoven fabric with dopamine indicated a lower water contact angle and better hydrophilicity that the water absorption ability nearly soared to ten times that ofPPnonwoven fabric withoutPDA.
Atomistic Investigation of Doping Effects on Electrocatalytic Properties of Cobalt Oxides for Water Oxidation
Authors: Kim Byunghoon , Park Inchul , Yoon Gabin , Kim Ju Seong , Kim Hyunah , Kang Kisuk 
Published: October 2018

AbstractThe development of high‐performance oxygen evolution reaction (OER) catalysts is crucial to achieve the clean production of hydrogen via water splitting. Recently, Co‐based oxides have been intensively investigated as some of the most efficient and cost‐effective OER catalysts. In particular, compositional tuning of Co‐based oxides via doping or substitution is shown to significantly affect their catalytic activity. Nevertheless, the origin of this enhanced catalytic activity and the reaction mechanism occurring at catalytic active sites remain controversial. Theoretical investigations are performed on the electrocatalytic properties of pristine and transition metal (Fe, Ni, and Mn)‐substituted Co oxides using first‐principle calculations. A comprehensive evaluation of the doping effects is conducted by considering various oxygen local environments in the crystal structure, which helps elucidate the mechanism behind the doping‐induced enhancement of Co‐based catalysts. It is demonstrated that the local distortion induced by dopant cations remarkably facilitates the catalysis at a specific site by modulating the hydrogen bonding. In particular, the presence of Jahn–Teller‐active Fe(IV) is shown to result in a substantial reduction in the overpotential at the initially inactive catalysis site without compromising the activity of the pristine active sites, supporting previous experimental observations of exceptional OER performance for Fe‐containing Co oxides.
Atom‐Transfer Radical Addition Photocatalysis Using a Heteroleptic Copper Complex
Authors: Matsuo Kazuki , Yamaguchi Eiji , Itoh Akichika 
Published: October 2018

AbstractHerein, we describe a photocatalyzed atom‐transfer radical addition (ATRA) reaction using a heteroleptic copper(I) complex bearing a bipyridyl‐based NN ligand and a 2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP) based PP ligand. The selected heteroleptic complex was [Cu(BINAP)(cup)](PF6), which was used because of its intense absorption in the visible region and its long excited‐state lifetime. The reported copper photocatalyzed reactions of olefins with carbon tetrabromide afford the products in moderate‐to‐excellent yields under irradiation with a 3 W, 400 nm light emitting diode (LED).
Alkene Synthesis Using Phosphonium Ylides as Umpolung Reagents
Authors: Duy Vu Minh , Leng Wei‐Lin , Hsu Hao‐Cheng , Liu Xue‐Wei 
Published: October 2018

AbstractWe report a transformation between a well‐known nucleophile, phosphonium ylide, and an electrophile. Subsequent ylide‐ylide coupling achieves unusual (Z)‐selectivity as compared to the conventional Wittig olefination. The synthesis of medium‐sized ring olefins has also been demonstrated, together with a one‐pot olefination from activated halides.
Simultaneous Trapping of C2H2 and C2H6 from a Ternary Mixture of C2H2/C2H4/C2H6 in a Robust Metal–Organic Framework for the Purification of C2H4
Authors: Hao Hong‐Guo , Zhao Yun‐Feng , Chen Di‐Ming , Yu Jia‐Mei , Tan Kui , Ma Shengqian , Chabal Yves , Zhang Zhi‐Ming , Dou Jian‐Min , Xiao Zi‐Hui , Day Gregory , Zhou Hong‐Cai , Lu Tong‐Bu 
Published: October 2018

AbstractThe removal of C2H2 and C2H6 from C2H4 streams is of great significance for feedstock purification to produce polyethylene and other commodity chemicals but the simultaneous adsorption of C2H6 and C2H2 over C2H4 from a ternary mixture has never been realized. Herein, a robust metal–organic framework, TJT‐100, was designed and synthesized, which demonstrates remarkably selective adsorption of C2H2 and C2H6 over C2H4. Breakthrough experiments show that TJT‐100 can be used as an adsorbent for high‐performance purification of C2H4 from a ternary mixture of C2H2/C2H4/C2H6 (0.5:99:0.5) to afford a C2H4 purity greater than 99.997 %, beyond that required for ethylene polymerization. Computational studies reveal that the uncoordinated carboxylate oxygen atoms and coordinated water molecules pointing towards the pore can trap C2H2 and C2H6 through the formation of multiple C−H⋅⋅⋅O electrostatic interactions, while the corresponding C2H4–framework interaction is unfavorable.
Mechanistische Studien in der Photokatalyse
Authors: Buzzetti Luca , Crisenza Giacomo E. M. , Melchiorre Paolo 
Published: October 2018

AbstractDie sich rasant entwickelnden Felder der Photo‐ und Photoredoxkatalyse bieten neue Gelegenheiten, das Potential der synthetisch‐organischen Chemie zu erweitern. Fortschritte bei photokatalytischen Prozessen haben sich bisher vor allem aus empirischen Entdeckungen und der Suche nach neuen Reaktionen ergeben. Die allgemeine Wahrnehmung jedoch ist, dass die Photokatalyse in eine reifere Phase eintritt, in der die Kombination experimenteller und mechanistischer Studien eine Vorreiterrolle für weitere Innovationen spielt. Dieser Aufsatz beschreibt die mechanistischen Schlüsselstudien, die bei der Entwicklung photochemischer Prozesse in Betracht gezogen werden sollten, sowie die geeignetsten verfügbaren Techniken zur Gewinnung relevanter Informationen. Die Diskussion verweist auf ausgewählte Fallstudien, um zu zeigen, wie mechanistische Untersuchungen eine instrumentelle Rolle bei der Entdeckung und Entwicklung synthetisch nützlicher, photokatalytischer Transformationen spielen können.
All‐Inorganic Ionic Porous Material Based on Giant Spherical Polyoxometalates Containing Core‐Shell K6@K36‐Water Cage
Authors: Li Zhong , Lin Li‐Dan , Yu Hao , Li Xin‐Xiong , Zheng Shou‐Tian 
Published: October 2018

AbstractThis work demonstrates that the use of high‐negative and high‐symmetry lacunary polyoxometalates (POMs) for the clustering of alkali metal ions is a feasible strategy not only for the formation of rare high‐nuclearity alkali‐metal clusters but also for the construction of new‐type all‐inorganic ionic porous materials. By the strategy, an unprecedented high‐nuclearity K‐H2O cluster {K42(H2O)60} with core–shell K6@K36 configuration is stabilized by 8 C3v‐symmetry trivacant POMs [GeW9O34]10−, forming a novel giant ionic alkali‐metal‐POM composite cluster {K42Ge8W72O272(H2O)60} with more than 100 metal centers. The incorporated 42‐nuclearity K‐H2O cluster {K42(H2O)60} exhibits the highest‐nuclearity alkali‐metal‐water cluster known to date in POM chemistry. Further, the giant {K42Ge8W72O272(H2O)60} clusters can be linked by another kind of alkali metal ions Na+ to generate a fascinating three‐dimensional all‐inorganic ionic porous framework with high chemical stability, proton conductivity, and water vapor adsorption.
Null Exciton Splitting in Chromophoric Greek Cross (+) Aggregate
Authors: Sebastian Ebin , Philip Abbey M. , Benny Alfy , Hariharan Mahesh 
Published: October 2018

AbstractExciton interactions in molecular aggregates play a crucial role in tailoring the optical behaviour of π‐conjugated materials. Though vital for optoelectronic applications, ideal Greek cross‐dipole (α=90°) stacking of chromophores remains elusive. We report a novel Greek cross (+) assembly of 1,7‐dibromoperylene‐3,4,9,10‐tetracarboxylic tetrabutylester (PTE‐Br2) which exhibits null exciton coupling mediated monomer‐like optical characteristics in the crystalline state. In contrast, nonzero exciton coupling in X‐type (α=70.2°, PTE‐Br0) and J‐type (α=0°, θ=48.4°, PTE‐Br4) assemblies have perturbed optical properties. Additionally, the semi‐classical Marcus theory of charge‐transfer rates predicts a selective hole transport phenomenon in the orthogonally stacked PTE‐Br2. Precise rotation angle dependent optoelectronic properties in crystalline PTE‐Br2 can have consequences in the rational design of novel π‐conjugated materials for photonic and molecular electronic applications.