bluuebunny/crossref_metadata_2025_split huggingface dataset:
Micromorphological and Chemotaxonomical Traits of Micromeria croatica (Pers.) Schott
Authors: Kremer Dario , Stabentheiner Edith , Dunkić Valerija , Müller Ivna Dragojević , Vujić Lovorka , Kosalec Ivan , Ballian Dalibor , Bogunić Faruk , Bezić Nada 
Published: April 2012

AbstractA study on the types and distribution of trichomes, pollen morphology, chemical composition of essential oil (analyzed by GC‐FID and GC/MS), and the content of macroelements (Na, K, Ca, and Mg) and trace elements (B, Fe, Cu, Mn, Zn, Al, Pb, Cr, Cd, Ni, Hg, and As) analyzed by ICP‐AES (=inductively coupled plasma atomic emission spectroscopy) was conducted on Micromeria croatica (Pers.) Schott. Non‐glandular trichomes, peltate trichomes (typical hairs of Lamiaceae), small capitate trichomes (composed of one basal epidermal cell and one head cell), and larger capitate trichomes (composed of one basal epidermal cell, two to three stalk cells, and one head cell with subcuticular space) were observed on leaves, stems, the calyx, and corolla. Pollen of M. croatica had six apertures (hexacolpate) which were set in the equatorial pollen belt (zonocolpate) and showed medium reticulate ornamentation (hetrobrochate type). The essential oil contained from 27 to 39 constituents, the most representative of which were caryophyllene oxide and E‐caryophyllene. Among the investigated macroelements, the content of K was highest (8730–10080 mg/kg). The content of trace elements ranged from 0.12 mg/kg (Cr) to 78.00 mg/kg (Fe), while the content of Cd, Ni, Hg, and As were lower than the limit of quantification.
Stabilized Hemiacetal Complexes as Precursors for the Controlled Release of Bioactive Volatile Alcohols
Authors: Buchs Barbara , Fieber Wolfgang , Drahoňovský Dušan , Lehn Jean‐Marie , Herrmann Andreas 
Published: April 2012

AbstractHemiacetals of pyridine‐2‐carbaldehyde derivatives and volatile alcohols can be stabilized in organic solution in the presence of protons or different metal cations. Despite the inherent instability of hemiacetals in H2O, stabilizing them with zinc(II) triflate and adding them to a cationic surfactant formulation resulted in the slow release of the alcohol from cotton surfaces being treated with the hemiacetal complex. Stabilized hemiacetals might thus be suitable delivery systems of bioactive volatiles by rapid hydrolysis in H2O‐based media.
Structurally Diverse Cyclisation Linkers Impose Different Backbone Conformations in Bicyclic Peptides
Authors: Chen Shiyu , Morales‐Sanfrutos Julia , Angelini Alessandro , Cutting Brian , Heinis Christian 
Published: April 2012

AbstractCombinatorial libraries of structurally diverse peptide macrocycles offer a rich source for the development of high‐affinity ligands to targets of interest. In this work we have developed linkers for the generation of genetically encoded bicyclic peptides and tested whether the peptides cyclised by them have significant variations in their backbone conformations. Two new cyclisation reagents, each containing three thiol‐reactive groups, efficiently and selectively cyclised linear peptides containing three cysteine moieties. When the mesitylene linker of the bicyclic peptide PK15, a potent inhibitor of plasma kallikrein (Ki=2 nM), was replaced by the new linkers, its inhibitory activity dropped by a factor of more than 1000, suggesting that the linkers impose different conformations on the peptide. Indeed, structural analysis by solution‐state NMR revealed different NOE constraints in the three bicyclic peptides, indicating that these relatively small linkers at the centres of bicyclic peptide structures significantly influence the conformations of the peptides. These results demonstrate the prominent structural role of linkers in peptide macrocycles and suggest that application of different cyclisation linkers in a combinatorial fashion could be an attractive means to generate topologically diverse macrocycle libraries.
Photochemical Modulation of Ras‐Mediated Signal Transduction Using Caged Farnesyltransferase Inhibitors: Activation by One‐ and Two‐Photon Excitation
Authors: Abate‐Pella Daniel , Zeliadt Nicholette A. , Ochocki Joshua D. , Warmka Janel K. , Dore Timothy M. , Blank David A. , Wattenberg Elizabeth V. , Distefano Mark D. 
Published: April 2012

AbstractThe creation of caged molecules involves the attachment of protecting groups to biologically active compounds such as ligands, substrates and drugs that can be removed under specific conditions. Photoremovable caging groups are the most common due to their ability to be removed with high spatial and temporal resolution. Here, the synthesis and photochemistry of a caged inhibitor of protein farnesyltransferase is described. The inhibitor, FTI, was caged by alkylation of a critical thiol group with a bromohydroxycoumarin (Bhc) moiety. While Bhc is well established as a protecting group for carboxylates and phosphates, it has not been extensively used to cage sulfhydryl groups. The resulting caged molecule, Bhc‐FTI, can be photolyzed with UV light to release the inhibitor that prevents Ras farnesylation, Ras membrane localization and downstream signaling. Finally, it is shown that Bhc‐FTI can be uncaged by two‐photon excitation to produce FTI at levels sufficient to inhibit Ras localization and alter cell morphology. Given the widespread involvement of Ras proteins in signal transduction pathways, this caged inhibitor should be useful in a plethora of studies.
Temporary Silicon‐Tethered Ring‐Closing Metathesis: Recent Advances in Methodology Development and Natural Product Synthesis
Authors: Čusak Alen 
Published: April 2012

AbstractTemporary silicon‐tethered ring‐closing metathesis represents an important cross‐coupling strategy for the formation of medium‐sized silacycles. These intermediates are valuable synthons in organic synthesis due to their propensity to undergo a facile refunctionalization through protodesilylation, oxidation, silane‐group transfer or transmetallation. A particularly attractive utility of this methodology is an application in the synthesis of biologically important natural products. The purpose of this review article is to highlight the recent progress in methodology development and its strategic application toward the target‐directed synthesis.
Heteroleptic Silylamido Phenolate Complexes of Calcium and the Larger Alkaline Earth Metals: β‐Agostic Ae⋅⋅⋅SiH Stabilization and Activity in the Ring‐Opening Polymerization of L‐Lactide
Authors: Liu Bo , Roisnel Thierry , Guégan Jean‐Paul , Carpentier Jean‐François , Sarazin Yann 
Published: April 2012

AbstractThe factors governing the stability and the reactivity towards cyclic esters of heteroleptic complexes of the large alkaline earth metals (Ae) have been probed. The synthesis and stability of a family of heteroleptic silylamido and alkoxide complexes of calcium [{LOi}CaNu(thf)n] supported by mono‐anionic amino ether phenolate ligands (i=1, {LO1}−=4‐(tert‐butyl)‐2,6‐bis(morpholinomethyl)phenolate, Nu−=N(SiMe2H)2−, n=0, 4; i=2, {LO2}−=2,4‐di‐tert‐butyl‐6‐{[2‐(methoxymethyl)pyrrolidin‐1‐yl]methyl}phenolate, Nu−=N(SiMe2H)2−, n=0, 5; i=4, {LO4}−=2‐{[bis(2‐methoxyethyl)amino]methyl}‐4,6‐di‐tert‐butylphenolate, Nu−=N(SiMe2H)2−, n=1, 6; Nu−=HCCCH2O−, n=0, 7) and those of the related [{LO3}AeN(SiMe2H)2] ({LO3}−=2‐[(1,4,7,10‐tetraoxa‐13‐azacyclopentadecan‐13‐yl)methyl]‐4,6‐di‐tert‐butylphenolate Ae=Ca, 1; Sr, 2; Ba, 3) have been investigated. The molecular structures of 1, 2, [(4)2], 6, and [(7)2] have been determined by X‐ray diffraction. These highlight Ae⋅⋅⋅HSi internal β‐agostic interactions, which play a key role in the stabilization of [{LOi}AeN(SiMe2H)2] complexes against ligand redistribution reactions, in contrast to regular [{LOi}AeN(SiMe3)2]. Pulse‐gradient spin‐echo (PGSE) NMR measurements showed that 1, 4, 6, and 7 are monomeric in solution. Complexes 1–7 mediate the ring‐opening polymerization (ROP) of L‐lactide highly efficiently, converting up to 5000 equivalents of monomer at 25 °C in a controlled fashion. In the immortal ROP performed with up to 100 equivalents of exogenous 9‐anthracenylmethanol or benzyl or propargyl alcohols as a transfer agent, the activity of the catalyst increased with the size of the metal (1<2<3). For Ca‐based complexes, the enhanced electron‐donating ability of the ancillary ligand favored catalyst activity (1>6>4≈5). The nature of the alcohol had little effect over the activity of the binary catalyst system 1/ROH; in all cases, both the control and end‐group fidelity were excellent. In the living ROP of L‐LA, the HCCCH2O− initiating group (as in 7) proved superior to N(SiMe2H)2− or N(SiMe3)2− (as in 6 or [{LO4}CaN(SiMe3)2] (B), respectively).
Potential Analysis of Smart Flow Processing and Micro Process Technology for Fastening Process Development – Use of Chemistry and Process Design as Intensification Fields
Authors: Hessel Volker , Gürsel Iris Vural , Wang Qi , Noël Timothy , Lang Jürgen 
Published: April 2012

AbstractKonti‐Prozesse mit mikrostrukturierten Reaktoren ermöglichen Paradigmenwechsel in der Prozessentwicklung und damit auch kürzere Entwicklungszeiten bis hin zur Produktionsanlage. Der Schlüssel liegt hier in analogen Prozesszuständen in der Entwicklungskette (Numbering‐up), Standardisierung (Modularität) und Intensivierung. Das Resultat ist letztendlich eine reduzierte Apparateanzahl und ‐größe und eine höhere Voraussagekraft im Scale‐out der Anlagen. Dies wird bislang meistens über die Transport‐Intensivierung in mikrostrukturierten Reaktoren bewirkt. Ein neuer, mehr und mehr genutzter Ansatz ist die Chemie‐Intensivierung durch Einsatz harscher Chemie bei ungewöhnlichen Reaktionsparametern und maßgeschneiderter Reaktionsumgebung. Eine ganz neuer Ansatz besteht zudem in der Prozessdesign‐Intensivierung – zum einen brauchen selektivitätsoptimierte Durchflussprozesse weniger Reinigungsaufwand, zum anderen haben mikrostrukturierte Reaktoren aufgrund ihrer kleinen Baugröße und der Möglichkeit zur internen Funktionalisierung großes Potenzial für die Systemintegration. Beide Maßnahmen verändern und vereinfachen das gesamte Prozessschema grundlegend. Der modulare Aufbau der kleinen Konti‐Einheiten erlaubt eine einfache Implementation in moderne modulare Anlagenumgebungen, in denen alle Testzyklen (Labor, Pilot, Produktion) in einer Anlagenumgebung durchgeführt werden sollen, wie z. B. Container‐Anlagen.
Nanoroses of Nickel Oxides: Synthesis, Electron Tomography Study, and Application in CO Oxidation and Energy Storage
Authors: Fihri Aziz , Sougrat Rachid , Rakhi Raghavan Baby , Rahal Raed , Cha Dongkyu , Hedhili Mohamed Nejib , Bouhrara Mohamed , Alshareef Husam N. , Polshettiwar Vivek 
Published: April 2012

AbstractNickel oxide and mixed‐metal oxide structures were fabricated by using microwave irradiation in pure water. The nickel oxide self‐assembled into unique rose‐shaped nanostructures. These nickel oxide roses were studied by performing electron tomography with virtual cross‐sections through the particles to understand their morphology from their interior to their surface. These materials exhibited promising performance as nanocatalysts for CO oxidation and in energy storage devices.
A transient‐improved low‐dropout regulator with nested flipped voltage follower structure
Authors: Chen Hua , Leung Ka Nang 
Published: April 2012

SUMMARYIn this article, the existing low‐dropout regulator (LDO) based on cascoded flipped voltage follower (CAFVF) is reviewed. A new method to simulate the open‐loop gain of an LDO with a CAFVF structure is conveyed. The drawback of CAFVF‐based LDO is that the nondominant pole locates at low‐frequency and pole‐zero cancellation using a large equivalent series resistance of loading capacitor is required for stability. To tackle this problem, a novel LDO structure based on a nested CAFVF is proposed and analyzed in this article. It is shown that the nondominant pole is pushed to a high frequency and the LDO stability is improved. The proposed circuit is fabricated using a commercial 0.35‐µm CMOS technology, and the load‐transient response between 0.5 and 60 mA settles at approximately 5 µs. Copyright © 2012 John Wiley & Sons, Ltd.
Island Homoaromaticity in the W‐Shaped 2,4‐Diphospha‐3‐arsapentadienide Anion and Related Compounds – Theoretical and Experimental Investigations
Authors: Rozhenko Alexander B. , Ruban Alexander , Thelen Vera , Nieger Martin , Airola Karri , Schoeller Wolfgang W. , Niecke Edgar 
Published: April 2012

AbstractA series of anions with general formula (R2C=P)2Pn– (Pn = N, P, As, Sb; R = H, Me, CF3, SiH3, SiMe3, SiF3) was investigated theoretically at the DFT (RI‐BP86/TZVP) and RI‐MP2/TZVP levels of approximation. Significantly sharpened central PPnP bond angles were predicted for the species with π‐acceptor R substituents. The corresponding bond angle values decrease in the order Pn = N >> P > As > Sb. This finding is in agreement with the previously published structural data for [(Me3Si)2C=P]2P–. An island homoaromaticity was proposed as a suitable explanation for the observed effect. In more detail, it consists of shifting negative charge to the electron‐withdrawing terminal groups with formation of a homologue of an aromatic heterocyclopropylium cation as the central moiety. Calculated structures and charge distributions are in agreement with the proposed model as well as with the molecular structure of the newly synthesized 2,4‐diphospha‐3‐arsapentadienyl anion.
The estimation of estuary dimensions using a simplified form model and the exogenous controls
Authors: Townend Ian 
Published: April 2012

ABSTRACTThe most common definition of an equilibrium condition for estuaries and inlets makes use of the well documented relationship between tidal prism and the cross‐sectional area of the channel. However, the tidal prism is itself a function of the morphology of the tidal basin. It would therefore be useful to be able to define the key dimensions of estuaries and inlets based on properties that are external to the estuary itself. This would then provide a more rigorous basis for understanding how systems are being ‘perturbed’ by developments, or other influences such as climate change. An idealized representation of the three–dimensional (3D) form of an estuary has been proposed and is here applied to a wide range of UK estuaries to explore its ability to predict the gross properties of a range of different estuary types. When considering just tidal flow, the model was found to provide an adequate representation, however, the inclusion of wave action was found to significantly improve the predictive power of the model. The exogenous parameters therefore provide a basis for determining the estuary dimensions and how they are likely to change over time. This in turn provokes a broader definition of an estuary than those commonly cited. Copyright © 2012 John Wiley & Sons, Ltd.
Obesity and depressive symptoms in the elderly: a survey in the rural area of Chizhou, Anhui province
Authors: Dong Qing , Liu Juan‐Juan , Zheng Rui‐Zhi , Dong Yong‐Hai , Feng Xiao‐Ming , Li Jie , Huang Fen 
Published: April 2012

ObjectiveThe aim of the present study is to examine the relationship between obesity and depressive symptoms and to test the “Jolly Fat” hypothesis among older Chinese.MethodsA total of 736 rural Chinese aged 60 years and older participated in this cross‐sectional study. Body mass index (BMI = kg/m2) was calculated from the subjects' measured weight (kg) and height (meter). Depressive symptoms were assessed using the 30‐item Geriatric Depression Scale (GDS‐30), with a cut‐off point of 11.ResultsAmong 736 total participants, the prevalence of depressive symptoms was 24.1% in men and 27.9% in women. A trend about depressive symptoms decreased with increasing BMI was found in men (χ2 trend = 5.74, df = 1, p = 0.01). A weak inverse linear trend between obesity and depressive symptoms was observed among subjects. In men, obese group was less likely to suffer from depressive symptoms compared with normal weight group before or after adjustment for confounders, with odds ratios of 0.32 (95% confidence interval (CI): 0.12–0.85) and 0.28 (95% CI: 0.09–0.85), respectively. However, the association between BMI and depressive symptoms in women showed no significant differences.ConclusionsOur results supported the “Jolly Fat” hypothesis only in rural older Chinese men, but not in women. Gender differences existed in the relationship between obesity and depressive symptoms. Copyright © 2012 John Wiley & Sons, Ltd.
Norlignans and Phenylpropanoids from Metasequoia glyptostroboidesHu et Cheng
Authors: Zeng Qi , Cheng Xiang‐Rong , Qin Jiang‐Jiang , Guan Bin , Chang Rui‐Jie , Yan Shi‐Kai , Jin Hui‐Zi , Zhang Wei‐Dong 
Published: April 2012

AbstractFive new compounds, i.e., the three new norlignans metasequirins G–I (1–3) and the two new phenylpropanoids 7‐(3‐ethoxy‐5‐methoxyphenyl)propane‐7,8,9‐triol (=1‐(3‐ethoxy‐5‐methoxyphenyl)propane‐1,2,3‐triol; 4) and 7‐(3‐hydroxy‐5‐methoxyphenyl)propane‐7,8,9‐triol (=1‐(3‐hydroxy‐5‐methoxy‐phenyl)propane‐1,2,3‐triol; 5), were isolated from the branches and stems of Metasequoia glyptostroboides Hu et Cheng. Their structures were elucidated by physical, chemical, and spectroscopic methods, including 1D‐ and 2D‐NMR and HR‐ESI‐MS. The cytotoxicites of the five compounds were tested against A549 and Colo 205 cell lines by the MTT method.
A Convergent Approach to Dibenzodioxocinones: Synthesis of Racemic Penicillide
Authors: Deng Chun‐Lin , Zhang Qiao , Fang Lisong , Lei Xinsheng , Lin Guoqiang 
Published: April 2012

AbstractA convergent approach to dibenzodioxocinones was explored, thereby racemic penicillide ((±)‐1a) could be obtained in 13 steps in 4.2% overall yield, based on 5‐amino‐2‐methylphenol (5) (Schemes 2–4).
Synthesis of 4‐Aryl‐1,7‐naphthyridine‐2(1H)‐thiones by the Electrocyclic Reaction of 4‐(1‐Arylalk‐1‐enyl)‐3‐isothiocyanatopyridines Generated in situ from the Corresponding Isocyanides
Authors: Kobayashi Kazuhiro , Kozuki Taketoshi , Suzuki Teruhiko 
Published: April 2012

AbstractA convenient synthis for 4‐substituted and 3,4‐disubstituted 1,7‐naphthyridine‐2(1H)‐thiones 7 has been developed. The method is based on the electrocyclic reaction of 4‐(1‐arylalk‐1‐enyl)‐3‐isothiocyanatopyridines 6, generated in situ by the treatment of the respective isocyanides 5 with S8 in the presence of a catalytic amount of selenium. The isocyanides 5 can be easily prepared from commercially available pyridin‐3‐amine by conventional organic reactions.
Sesquiterpenoids and 2‐(2‐Phenylethyl)‐4H‐chromen‐4‐one (=2‐(2‐Phenylethyl)‐4H‐1‐benzopyran‐4‐one) Derivatives from Aquilaria malaccensis Agarwood
Authors: Wu Bo , Lee Jin Gyun , Lim Chang Ju , Jia Shao Dong , Kwon Sung Won , Hwang Gwi Seo , Park Jeong Hill 
Published: April 2012

AbstractThe four new sesquiterpenoids 1–4, and the new 2‐(2‐phenylethyl)‐4H‐chromen‐4‐one (=2‐(2‐phenylethyl)‐4H‐1‐benzopyran‐4‐one) derivative 5, together with the two known sesquiterpenoids 6 and 7, the five known chromenones 8–12, and 1‐hydroxy‐1,5‐diphenylpentan‐3‐one (13), were isolated from a 70% MeOH extract of Aquilaria malaccensis agarwood chips. Their structures were elucidated on the basis of comprehensive spectral analyses and comparison with literature data.
A New Abietane Diterpenoid from Plectranthus bishopianusBenth.
Authors: Syamasundar Kodakandla Venkata , Vinodh Guvvala , Srinivas Kalavagunta Venkata Naga Satya , Srinivasulu Bogineni 
Published: April 2012

AbstractChemical examination of the MeOH extract of Plectranthus bishopianus Benth., a rare and endangered plant, resulted in isolation of a new abietane diterpene, 6β‐hydroxy‐7α‐methoxyroyleanone (1), along with two more diterpenoids, 6,7‐dehydroroyleanone, and 6β,7α‐dihydroxyroyleanone, a triterpene oleanolic acid, and two sterols, β‐sistosterol and stigmasterol. The structures of the isolated compounds were elucidated on the basis of spectroscopic data and also by comparison with authentic samples.
Unexpected Course of the Reaction of 2‐Unsubstituted 1H‐Imidazole 3‐Oxides with Ethyl Acrylate
Authors: Mlostoń Grzegorz , Urbaniak Katarzyna , Wojciechowska Alicja , Linden Anthony , Heimgartner Heinz 
Published: April 2012

AbstractThe attempted ethenylation at C(2) of 2‐unsubstituted 1H‐imidazole N‐oxides with ethyl acrylate (=prop‐2‐enoate) in the presence of Pd(OAc)2 does not occur. In contrast to the other aromatic N‐oxides, the [2+3] cycloaddition of imidazole N‐oxides predominates, and 3‐hydroxyacrylates, isomeric with the cycloadducts, are key products for the subsequent reaction. The final products were identified as dehydrated 2+1 adducts of 1H‐imidazole N‐oxide and ethyl acrylate. The role of the catalyst is limited to the dehydration of the intermediate 3‐hydroxypropanoates to give 1H‐imidazol‐2‐yl‐substituted acrylates.
OVERCROWDING VERSUS LIQUIDITY IN THE EURO SOVEREIGN BOND MARKETS
Authors: Coppola Andrea , Girardi Alessandro , Piga Gustavo 
Published: April 2012

ABSTRACTWith the adoption of a common currency, the degree of substitution between financial instruments supplied by EMU Member States to finance their national debts has risen. Providing the market for euro‐denominated government securities with a large volume of similar financial instruments is likely to increase liquidity and lower yields. By contrast, providing an excessive volume of the same instrument might increase the return demanded by investors. This paper aims at empirically assessing the balance between liquidity and overcrowding effects by EMU countries' issuance plans. Our results document a significant relationship between bunching in issues and bond yields. Copyright © 2012 John Wiley & Sons, Ltd.
Specificity of latent TGF‐β binding protein (LTBP) incorporation into matrix: Role of fibrillins and fibronectin
Authors: Zilberberg Lior , Todorovic Vesna , Dabovic Branka , Horiguchi Masahito , Couroussé Thomas , Sakai Lynn Y. , Rifkin Daniel B. 
Published: April 2012

AbstractFibrillin microfibrils are extracellular matrix structures with essential functions in the development and the organization of tissues including blood vessels, bone, limbs and the eye. Fibrillin‐1 and fibrillin‐2 form the core of fibrillin microfibrils, to which multiple proteins associate to form a highly organized structure. Defining the components of this structure and their interactions is crucial to understand the pathobiology of microfibrillopathies associated with mutations in fibrillins and in microfibril‐associated molecules. In this study, we have analyzed both in vitro and in vivo the role of fibrillin microfibrils in the matrix deposition of latent TGF‐β binding protein 1 (LTBP‐1), ‐3 and ‐4; the three LTBPs that form a complex with TGF‐β. In Fbn1−/− ascending aortas and lungs, LTBP‐3 and LTBP‐4 are not incorporated into a matrix lacking fibrillin‐1 microfibrils, whereas LTBP‐1 is still deposited. In addition, in cultures of Fbn1−/− smooth muscle cells or lung fibroblasts, LTBP‐3 and LTBP‐4 are not incorporated into a matrix lacking fibrillin‐1 microfibrils, whereas LTBP‐1 is still deposited. Fibrillin‐2 is not involved in the deposition of LTBP‐1 in Fbn1−/− extracellular matrix as cells deficient for both fibrillin‐1 and fibrillin‐2 still incorporate LTBP‐1 in their matrix. However, blocking the formation of the fibronectin network in Fbn1−/− cells abrogates the deposition of LTBP‐1. Together, these data indicate that LTBP‐3 and LTBP‐4 association with the matrix depends on fibrillin‐1 microfibrils, whereas LTBP‐1 association depends on a fibronectin network. J. Cell. Physiol. 227: 3828–3836, 2012. © 2012 Wiley Periodicals, Inc.