bluuebunny/crossref_metadata_2025 huggingface dataset:
Novel Liquid Crystalline Compounds Containing Bicyclo[3.1.0]hexane Core Units
Authors: Kozhushkov Sergei I. , Langer Rainer , Yufit Dmitrii S. , Howard Judith A. K. , Schill Heiko , Demus Dietrich , Miyazawa Kazutoshi , de Meijere Armin
Published: January 2004

Additions of ethyl ortert‐butyl diazoacetates to 4‐substituted cyclopentenes6and17under dirhodium tetraacetate/tetraoctanoate catalysis led to mixtures oftert‐butylendo,exo‐ andexo,exo‐3‐carboxyl(aryl)bicyclo[3.1.0]hexane‐6‐carboxylates7and18in yields of 54−90% from whichexo,exo‐diastereomers were isolated in yields of 39−63%. Diesterexo,exo‐7was saponified and converted into diaryl diestersexo,exo‐9a,bin overall yields of 42 and 46%, respectively. The estersexo,exo‐18were reduced to the corresponding hydroxymethyl derivatives, these were transformed to the iodomethyl compounds which in turn were coupled with various alkylmagnesium halides, via Li2CuCl4catalysis, to give 3‐aryl‐6‐alkylbicyclo[3.1.0]hexyl derivativesexo,exo‐21in overall yields of 72−83%. Fluorinated 3‐(2‐arylethyl)‐6‐pentylbicyclo[3.1.0]hexaneexo,exo‐32could be prepared in five steps from 4‐ethoxy‐2,3‐difluorobenzaldehyde26aadopting essentially the same synthetic strategy, but in an overall yield of only 8%, and 6‐(4‐cyanophenyl)‐3‐pentylbicyclo[3.1.0]hexaneexo,exo‐38bwas obtained by Pd(OAc)2catalyzed cyclopropanation of 4‐pentylcyclopentene34bwith (4‐cyanophenyl)diazomethane36bin 29% yield. A comparison of the liquid crystalline properties of these newly prepared compounds containing a bicyclo[3.1.0]hexane core with those of the known analogous compounds with a cyclohexane fragment shows that as a rule, a bicyclo[3.1.0]hexane moiety decreases the transition temperature, while the dielectric (Δϵ) and optical (Δn) anisotropies are comparable. However, the bicyclo[3.1.0]hexane unit has a poorer mesogenic potential. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Efficient Synthesis of Unsymmetrical Ureido‐Linked Disaccharides
Authors: Prosperi Davide , Ronchi Silvia , Lay Luigi , Rencurosi Anna , Russo Giovanni
Published: January 2004

Five nonsymmetrical urea‐linked disaccharides, in which two glycopyranoside units are bound at the 1⇄2, 1⇄4, and 1⇄6 positions, were efficiently synthesized. A mild and safe procedure, in which glycosyl isocyanates were coupled with a glycosylamine, was employed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tuning the Photochromic Properties of a Flavylium Compound by pH
Authors: Moncada Margarida C. , Pina Fernando , Roque Ana , Parola A. Jorge , Maestri Mauro , Balzani Vincenzo
Published: January 2004

We studied the intricate pH‐ and light‐dependent network of the thermal and photochemical reactions of the 4′‐(dimethylamino)‐7‐hydroxyflavylium ion by continuous irradiation, flash photolysis, 1H NMR spectroscopy, and stopped flow analysis. The distribution of the various forms at the pH‐dependent thermodynamic equilibrium and the rates of several interconversion processes were measured. The most interesting feature of this multistate/multifunctional system is related to the possibility of pH‐tuning the colour change caused by photoirradiation, because the cis‐chalcone isomer, obtained from the photoisomerization of the trans‐chalcone form, is spontaneously transformed into coloured species (flavylium cation and quinoidal base) at low values of pH, but reverts back to the uncoloured trans‐chalcone at high values of pH because of the low energy barrier between the cis and trans chalcone isomers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Theoretical and Experimental Study of the Regioselectivity of Michael Additions
Authors: Chatfield David C. , Augsten Alberto , D'Cunha Cassian , Lewandowska Elzbieta , Wnuk Stanislaw F.
Published: January 2004

Nucleophilic attack at an α,β‐unsaturated carbonyl moiety usually results in conjugate addition at the β‐carbon atom (1,4 or Michael addition) or, occasionally, in addition at the carbonyl carbon atom (1,2 addition). Recently, however, addition at the α‐carbon atom has been observed when strongly electron‐withdrawing groups are positioned at the carbon atom β relative to the carbonyl group [e.g., methyl 3,3‐bis(trifluoromethyl)propenoate (8) and ethyl 3‐(2,4‐dinitrophenyl)propenoate (24)]. We have performed theoretical calculations [HF/6−31+G(d) and B3LYP//HF/6−31+G(d)] for the addition of cyanide anion to model α,β‐unsaturated carbonyl compounds to determine trends in the regioselectivity with respect to properties of the substituents. The difference between the reaction barriers for α‐ vs. β‐addition decreases as the strength of electron‐withdrawing groups increases until, for sufficiently strong electron‐withdrawing groups, α‐addition becomes favored. The calculations are in agreement with the experimental results. We show that the regioselectivity can be predicted from partial atomic charges and properties of the frontier orbitals of the reactants. We also report new experimental evidence of α‐addition to polysubstituted cinnamates and cinnamaldehydes. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Novel Anti‐Inflammatory Spongian Diterpenes from the New Zealand Marine SpongeChelonaplysilla violacea
Authors: Keyzers Robert A. , Northcote Peter T. , Zubkov Oleg A.
Published: January 2004

Six novel rearranged spongian diterpenes were isolated from the New Zealand spongeChelonaplysilla violacea. The structures of the six metabolites were determined by extensive spectral analysis. Three of the new compounds possess anti‐inflammatory activity. Pourewic acid A (4) and 15‐methoxypourewic acid B (5) represent possible intermediates in previously described biogenetic pathways. Pourewanone (3) is the first example of a formate to be isolated from the marine environment. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis and Odor of Aliphatic Musks: Discovery of a New Class of Odorants
Authors: Kraft Philip , Eichenberger Walter
Published: January 2004

To find new aliphatic musks, we synthesized the propionates of 2‐[1′‐(3′′,3′′‐dimethylcyclohex‐1′′‐enyl)ethoxy]‐2‐methylpropanol (8), of 2‐[1′‐(5′′,5′′‐dimethylcyclohex‐1′′‐enyl)ethoxy]‐2‐methylpropanol (11), of hydroxyacetic acid 1‐(3′,3′‐dimethylcyclohex‐1′‐enyl)ethyl ester (12), and of hydroxyacetic acid 1‐(5′,5′‐dimethylcyclohex‐1′‐enyl)ethyl ester (13) starting from 1‐(3′,3′‐dimethylcyclohex‐1′‐enyl)ethanone (5) and 1‐ethynyl‐3,3‐dimethylcyclohexanol (9). We found that the 3,3‐dimethylcyclohexenyl derivatives8(odor threshold 0.2 ng/air) and12(odor threshold 0.6 ng/air) are superior musk odorants, and, thus, we constructed 1,2,4‐trimethylpent‐2‐enyloxy analogues assecoversions. The synthesis of the esters17−26commenced with a Wittig−Horner− Emmons reaction of isobutyric aldehyde (14), followed by saponification, alkylation with methyllithium, LAH reduction, etherification with isobutylene oxide, and Steglich esterification. (2′′E)‐2′‐Methyl‐2′‐(1′′,2′′,4′′‐trimethylpent‐2′′‐enyloxy)propyl cyclopropanecarboxylate [(2′′E)‐19], which has a powerful and sweet musk odor and slightly fruity nuances, was found to be a typical representative of this new class of musk odorants, was subjected to conformational analysis. In addition, we report the synthesis and olfactory properties of the related ketones28−30, the 2‐methyl‐2‐(1′,4′,4′‐trimethylpent‐2′‐enyloxy)propyl esters31−33, and the 2‐(1′,4′‐dimethylpent‐2′‐enyloxy)‐2‐methylpropyl esters35and36. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Hydrogen Migration Over Organic Tapes: [1,5] Sigmatropic Shiftamers
Authors: Tantillo Dean J. , Hoffmann Roald
Published: January 2004

We explore the possibility of suprafacial hydrogen atom migration over several organic tapes—infinite chains of polycyclic conjugated hydrocarbons. It’s not easy. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Evidence for Intramolecular Ylide Formation in the Decay of a Singlet Aryl Nitrene
Authors: Tönshoff Christina , Bucher Götz
Published: January 2004

The photolysis of the azido‐functionalized cryptand 1 yields the benzopyrazole 2. The formation of 2 is rationalized to occur via the nitrene ammonium ylide 4, which undergoes ring‐opening by an intramolecular E2 elimination mechanism. The benzopyrazoline thus formed is then oxidized during aerobic workup. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Cover Picture: Hydrogen Migration Over Organic Tapes: [1,5] Sigmatropic Shiftamers (Eur. J. Org. Chem. 2/2004)
Authors: Tantillo Dean J. , Hoffmann Roald
Published: January 2004

The cover picture shows several polycyclic organic tapes over which hydrogen atoms might migrate. While hydrogen migration over metal surfaces is commonplace, the facility of analogous processes in most fully organic systems is not known. Using quantum chemical calculations, D. J. Tantillo and R. Hoffmann estimate the energetic barriers associated with hydrogen migration in these and other systems. For more details, see the article on p. 273 ff.
Analysis of enantiomeric ratios of aroma components in several ﬂowers using a Chiramix column
Authors: Tamogami Shigeyuki , Awano Ken‐ichi , Amaike Masayasu , Takagi Yoshikazu , Kitahara Takeshi
Published: January 2004

A novel GLC column, which we named ‘Chiramix’, which was coated with a mixture of two chiral stationary phases, heptakis‐(2, 6‐di‐O‐methyl‐3‐O‐pentyl)‐β‐cyclodextrin (2, 6‐Me‐3‐Pe‐β‐CD) and octakis‐(2, 6‐di‐O‐methyl‐3‐O‐triﬂuoroacetyl)‐γ‐cyclodextrin (2, 6‐Me‐3‐TFAc‐γ‐CD), has proved to be greatly superior to those with single chiral phase for separating enantiomers of compounds having various functional groups. Extensive applications to analyse enantiomeric ratios of aroma components in several popular ﬂowers hitherto not analysed by this method were further carried out, again proving that most optical isomers of the components were signiﬁcantly easily separated using the Chiramix column.
Chemical composition of the essential oils of Ageratum conyzoides L. occurring in south China
Authors: Sundufu Abu James , Shoushan Huang
Published: January 2004

The essential oil isolated from the leaves and ﬂowers of Ageratum conyzoides L. were analysed by GC and GC–MS. The oil contained ageratochromene (precocene II, 25.89%); the sesquiterpene β‐caryophyllene (23.79%); demethoxyageratochromene (precocene I, 14.76%) and some monoterpene hydrocarbons, with percentages of 2–5.5%. Comparative analysis with data from Cameroon, Ghana and Vietnam is also reported. Copyright © 2003 John Wiley & Sons, Ltd.
Aromatic plants of tropical central Africa. Part XLIV.# Volatile components from Pseudocedrela kotschyi (Schweinf.) harms growing in Cameroon
Authors: Boyom F. Fekam , Fotio D. , Zollo P. H. Amvam , Agnaniet H. , Menut C. , Bessière J. M.
Published: January 2004

The essential oils obtained from stem and root barks of Pseudocedrela kotschyi (Schweinf.) Harms (Meliaceae) collected in Cameroon were analysed by GC and GC–MS. The two samples were found to be composed exclusively of sesquiterpenoids. The hydrocarbons were found to be most abundant in the stem bark extract, with δ‐cadinene (31.3%) as the main constituent, while the root bark oil contained a majority of oxygenated sesquiterpenoids, with cubebols representing almost one‐third of the extract. The antioxidant and antiradical activities of both samples were found to be very low compared with those of the reference compounds. Copyright © 2003 John Wiley & Sons, Ltd.
Steam volatile leaf oils of some Western Australian species of the family Myrtaceae
Authors: Lassak Erich V. , Brophy Joseph J.
Published: January 2004

The essential oils of Agonis obtusissima F. Muell., Eremaea pauciﬂora (Endl.) Druce, Eucalyptus erythrocorys F. Muell., Eucalyptus stoatei C. Gardner, Kunzea pulchella (Lindl.) A. S. George, Malleostemon tuberculatus (E. Pritzel) J. W. Green, Melaleuca uncinata R. Br., Thryptomene australis Endl. and Thryptomene kochii E. Pritzel have been extracted by cohobative water‐distillation of the leaves and terminal branchlets. The oils of Kunzea pulchella (both the red and the white‐ﬂowered forms) contained globulol (83–88%). The oils of Thryptomene australis contained geranic acid (52%) and α‐pinene (22%), whilst T. kochii oils contained α‐pinene (58–60%). Eremaea pauciﬂora oil contained 1,8‐cineole (22%) and the three isomeric eudesmols (α‐, β‐, γ‐; 26%). Agonis obtusissima oil contained α‐pinene (12%), trans‐β‐ocimene (16%) and globulol (39%). Malleostemon tuberculatus oil contained α‐pinene (33%), 1,8‐cineole (21%) and E,E‐farnesol (6%). The oil of Melaleuca uncinata, rich in α‐pinene (89%), represents the hydrocarbon form of this species. The oil of Eucalyptus erythrocorys contained 1,8‐cineole (59%) and α‐pinene (12%), whilst the oil of Eucalyptus stoatei contained α‐pinene (32%), 1,8‐cineole (26%), globulol (10%) and the three isomeric eudesmols (α‐, β‐, γ‐, 11%). Copyright © 2003 John Wiley & Sons, Ltd.
Volatile organic compounds from saffron
Authors: D'Auria Maurizio , Mauriello Giacomo , Rana Gian Luigi
Published: January 2004

SPME–GC–MS analysis on four samples of saffron from different areas of Italy and from Iran were performed. Sample 1 was derived from cultivations of Crocus sativus in the zone of Salerno (Southern Italy). Sample 2 was derived from cultivations in Sardinia, Italy. Sample 3 was derived from cultivations in Abruzzo (Central Italy). Sample 4 was derived from Iran. The main components were those found in ethereal extract of saffron in a work published in 1971. Several compounds found by using other extraction—distillation techniques were not found. We found 18 compounds never discovered in saffron. In all the samples, 3,5,5‐trimethyl‐2‐cyclohexen‐1‐one, 3,5,5‐trimethyl‐2‐cyclohexen‐1,4‐dione, safranal and 2,4,4‐trimethyl‐6‐hydroxy‐3‐carboxaldehyde‐2,5‐cyclohexadien‐1‐one were found. 3,5,5‐Trimethyl‐1,4‐cyclohexandione was found in three samples. 5,5‐Dimethyl‐2‐methylene‐1‐carboxaldehyde‐3‐cyclohexene, β‐ionone were found in six samples, and nonanal, and 2,6‐di‐t‐butylphenol were found in two samples. These compounds represent the compounds found with the highest frequency. Considering the relative amount of the components, safranal is the main component in all the samples. The analyses show that saffrons from different cultivation sites have some peculiarities due to the presence of some unusual components. The sample from Iran showed the presence of 3,5,5‐trimethyl‐2‐hydroxy‐2‐cyclohexen‐1‐one, 2,7,7‐trimethyl2,4‐cycloheptadien‐1‐one, 1,3,3‐trimethyl‐2‐(E‐2‐butenylidene)‐3‐cyclo‐hexene, 5,5‐dimethyl‐1,3‐cyclohexadien‐1‐carbaldehyde, 1,1,3‐trimethyl‐2‐(Z‐2‐butenylidene)‐3‐cyclohexene, 1‐acetyl‐5,5‐dimethyl‐bycyclo[3.1.0]hexane, and β‐ionol. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of feeding of 2‐phenylethyl glucopyranoside on the scent emission of cut ﬂowers
Authors: Ikemoto Takeshi , Nagai Tomoo , Fujita Akira , Iwamoto Minoru
Published: January 2004

The ﬂoral notes of two types of cut ﬂowers, rose (Rote rose) and baby's breath (Gypsophilia elegans), were dramatically changed when the cut stems were immersed in a vase solution containing 2‐phenylethyl β‐d‐glucopyranoside (PEBG). In a comparison between an untreated control R. rose and a treated R. rose placed in a vase solution containing 0.5% PEBG, approximately 500 times more 2‐phenylethyl alcohol was detected from the ﬂoret of the latter. In a similar comparison using G. elegans, the headspace of the treated ﬂower not only had increased levels of 2‐phenylethyl alcohol but also had decreased levels of isovaleric acid and 2‐methyl butyric acid, the main malodorous components of the ﬂower. These results suggested, ﬁrst, that PEBG is useful as a fragrance enhancer for cut ﬂowers, and second, that it may play a role in the fragrance formation of glycoside ﬂowers. Copyright © 2003 John Wiley & Sons, Ltd.
Aromatic plants from Patagonia. Part I. Antimicrobial activity and chemical composition of Schinus polygamus (Cav.) Cabrera essential oil
Authors: González Silvia , Guerra Pedro E. , Bottaro Hugo , Molares Soledad , Demo Mirta S. , Oliva Maria M. , Zunino Maria P. , Zygadlo Julio A.
Published: January 2004

The essential oil of Schinus polygamus (Cav.) Cabrera f: chubutensis (syn. S. marchandii Barkley) was analysed for the ﬁrst time by means of GC and GC–MS. Of 30 identiﬁed compounds, representing 96.3% of the oil, α‐phellandrene and limonene were the major components. The oil showed high antimicrobial activity against B. cereus. Copyright © 2003 John Wiley & Sons, Ltd.
Maturity discrimination of snake fruit (Salacca edulis Reinw.) cv. Pondoh based on volatiles analysis using an electronic nose device equipped with a sensor array and ﬁngerprint mass spectrometry
Authors: Supriyadi  , Shimizu Kanako , Suzuki Masayuki , Yoshida Koichi , Muto Tokie , Fujita Akira , Tomita Naomi , Watanabe Naoharu
Published: January 2004

GC–olfactometry was used to characterize the speciﬁc aroma of a pentane extract of snake fruit (Salacca edulis Reinw cv. Pondoh). Ten compounds, including two carboxylic acids, six methyl esters, an alcohol and a furaneol (2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone), were detected as the most characteristic odorants. Methyl esters exhibited particularly sweet and fruity odour characteristics in snake fruit at more mature stages, whereas carboxylic acids exhibited the sweaty odour that tends to prevent non‐native consumers from liking the fruit. A headspace of snake fruit at different stages of maturation was subjected to analysis using two analytical systems an electronic nose equipped with 18 sensors and ﬁngerprint mass spectrometry. Three sensors and ﬁve ions derived from esters were chosen as ﬁngerprint parameters to discriminate between maturation levels. Both systems appeared to discriminate efﬁciently between the fruits at different maturation stages. Copyright © 2003 John Wiley & Sons, Ltd.
Effect of extraction methods on the chemical composition and antioxidant activity of Egyptian marjoram (Majorana hortensis Moench)
Authors: El‐Ghorab Ahmed H. , Mansour Amr F. , El‐massry Khaled F.
Published: January 2004

The volatile extract compositions of marjoram (Majorana hortensis Moench) leaves obtained by hydrodistillation (HD) and supercritical ﬂuid extraction (SFE) were estimated by gas chromatography–mass spectrometry (GC–MS); 26 components were identiﬁed. The major compounds in both extracts were terpinen‐4‐ol (20.39% and 10.96%), γ‐terpinene (14.13% and 8.14%), trans‐sabinene hydrate (5.25% and 20.54%), linalool (3.72% and 4.06%), trans‐sabinene hydrate acetate (0% and 13.01%), thujanol (4.00% and 4.12%), terpinolene (4.57% and 3.70%) and thymol (0.33% and 1.18%) in HD and SFE extracts, respectively. The total monoterpene hydrocarbons are higher in HD oil (42.57%) than that of SFE extract (22.80%). However, the SFE extract possessed higher concentrations of light oxygenated compounds, which give the oil a superior aroma. Both extracts effectively inhibited the peroxide formation of linoleic acid. The antioxidant property of the SFE extract is markedly higher than that of butylated hydroxyanisol (BHA) and HD extract, which might be due to the presence of higher contents of γ‐terpinene, terpinolene and thymol. At higher concentrations, both extracts showed higher antioxidant activity compared to BHA. In order to enhance the activity of the natural extracts examined and decrease the applicability of synthetic antioxidants, the synergistic effect was also studied by adding BHA to either extracts. The mixture of either extracts and BHA results in an additive effect of their antioxidant capacities in comparison to their individual activity. Copyright © 2003 John Wiley & Sons, Ltd.
Composition and antifungal activity of essential oils isolated from Hypericum hyssopifolium and Hypericum heterophyllum
Authors: Cakir A. , Kordali S. , Zengin H. , Izumi S. , Hirata T.
Published: January 2004

The composition of the hydrodistilled essential oils obtained from the aerial parts of Hypericum hyssopifolium subsp. elongatum var. elongatum and H. heterophyllum Vent. were analysed by means of GC and GC–MS, and 66 compounds were determined in total. The oils showed remarkable differences in chemical composition. The oil of H. hyssopifolium, which is rich in monoterpenes, consists primarily of α‐pinene (57.3%), β‐pinene (9.0%), limonene (6.2%) and α‐phellandrene (4.4%). The oil of H. heterophyllum was a complex mixture consisting mainly of sesquiterpenes (72.9% of the total oil). In this oil, isocaryophyllene (17.1%), α‐pinene (11.6%), δ‐cadinene (9.5%), γ‐muurolene (8.2%), n‐decane (5.8%), γ‐cadinene (5.5%) and β‐caryophyllene (4.5%) were found to be major constituents. The two essential oils were tested for antifungal activity using microbial growth inhibition assays in vitro against 10 agricultural pathogenic fungi, which consisted of ﬁve Fusarium species (F. oxysporum, F. culmorum, F. sambucinum, F. solani and F. acuminatum) and ﬁve anastomosis groups of Rhizoctonia solani (AG‐3, AG‐4, AG‐5, AG‐9 and AG‐11). In general, the oils showed moderate activity against several fungal species, viz F. acuminatum, AG‐5 and AG‐11. The most signiﬁcant results were obtained against AG‐11 for H. heterophyllum oil. However, both oils increased the growth of some fungal species. In addition, the antifungal activity of 13 pure compounds identiﬁed as major components in the essential oils of the Hypericum species studied were determined using microbial growth inhibition assays against the 10 fungal species mentioned above. Among these compounds, both β‐caryophyllene oxide and α‐terpineol were inhibitory to the growth of all fungi. Copyright © 2003 John Wiley & Sons, Ltd.
Neutral components from hexane extracts of Croton sellowii
Authors: Palmeira Sebastião F. , Moura Fabyanne de S. , Alves Vanessa de L. , Oliveira Fernando M. de , Bento Edson S. , Conserva Lucia M. , Andrade Eloisa Helena de A.
Published: January 2004

Qualitative analyses by GC–FID and GC–MS of the neutral fractions from hexane extract of the leaves, stems and roots of Croton sellowii were carried out. Sesquiterpenoids, n‐alkanes, aliphatic esters and aliphatic alcohols and alkyl benzene derivatives were identiﬁed. Caryophyllene oxide (46.8%) and trans‐caryophyllene (40.8%) were most abundant in the leaves, while caryophyllene oxide (26.5%) and cubenol (16.7%) were the main constituents in the stems. In the roots, besides mesitylene (15.2%), the sesquiterpenes γ‐(7.6%), α‐(6.9%) and β‐eudesmol (5.5%) were the most abundant components. All identiﬁed constituents are described for the ﬁrst time in this species. Copyright © 2003 John Wiley & Sons, Ltd.
The volatiles of fresh‐cut Osyris alba L. flowers
Authors: Demirci Fatih , Başer K. Hüsnü Can
Published: January 2004

Osyris alba L. (Santalaceae) was subjected to headspace–solid phase microextraction (HS–SPME) and subsequent GC–MS analysis due to the strong fragrance of volatiles emitted by the freshly collected ﬂowering branches. SPME with polydimethylsiloxane/divinylbenzene (PDMS/DVB) ﬁbre resulted in the identiﬁcation of 13 hexyl and hexenyl derivatives with a fruity, pear‐type, leafy green odour. Copyright © 2003 John Wiley & Sons, Ltd.
Essential oil composition of Hypericum brasiliense choise
Authors: Abreu Ilka N. , Reis Mariza G. , Marsaioli Anita J. , Mazzafera Paulo
Published: January 2004

The essential oil of the Hypericum brasiliense was obtained by hydrodistillation and its composition studied by GC–MS. The oil represented to 0.1% of the dried material and 20 substances were identiﬁed, forming 94.17% of the total oil. Sesquiterpenes were the major constituents (93.14%) of the oil and β‐caryophyllene (29.53%) was the main substance. The oxygenated sesquiterpenes in H. brasiliense represented 12.7% of the oil, and caryophyllene oxide (9.95%) was the major constituent of this fraction. Compared with other species of the genus, the composition of the essential oil of H. brasiliense is closer to the composition of H. perforatum. Copyright © 2003 John Wiley & Sons, Ltd.
Age‐dependent changes in the nervous and endocrine control of the thymus
Authors: Hannestad Jonas , Monjil Diego F. , Díaz‐Esnal Belén , Cobo Juan , Vega José A.
Published: January 2004

The immune system, especially the thymus, undergoes age‐related modifications leading to structural and functional changes in the lymphoid organs and immunocompetent cells. Nevertheless, the consequences of thymic involution in the peripheral pool of T‐cells are still a matter of controversy. The control of the thymic function is very complex and involves intrathymic signals, the autonomic nervous system, and the endocrine system. Both thymocytes and thymic stromal cells express receptors for a wide range of hormones, as well as for neurotransmitters and neuropeptides, thus affecting thymocytes maturation. This review summarizes the age‐dependent variations in the extrathymic components of the thymic microenvironment, i.e., vegetative nerves and hormones, and the possible effects of those changes in the immune function. Microsc. Res. Tech. 63:94–101, 2004. © 2004 Wiley‐Liss, Inc.
Simultaneous fixation using glutaraldehyde and osmium tetroxide or potassium ferricyanide‐reduced osmium for the preservation of monogenean flatworms: An assessment for Merizocotyle icopae
Authors: Cribb Bronwen , Armstrong Wendy , Whittington Ian
Published: January 2004

Simultaneous fixation was investigated for a marine organism: the monogenean flatworm ectoparasite Merizocotyle icopae. Four protocols for primary fixation were compared: 3% glutaraldehyde alone in 0.1M cacodylate buffer for a minimum of 2 hours; 1% glutaraldehyde in combination with 1% osmium tetroxide, both in 0.1M cacodylate buffer, until tissues darkened (5–20 minutes); 1% glutaraldehyde in 0.1M cacodylate buffer in combination with 0.5% potassium ferricyanide‐reduced osmium until tissues darkened (5–20 minutes); 1% glutaraldehyde in combination with 1% osmium tetroxide, both in 0.1M cacodylate buffer, for 30 minutes. The study confirms that the standard method for transmission electron microscopic fixation (first listed protocol) routinely applied to platyhelminths is optimal for ultrastructural preservation, but some simultaneous fixation methods (second and third listed protocols) are acceptable when rapid immobilization is needed. Scanning electron microscopic preparations may be improved using simultaneous primary fixation. Microsc. Res. Tech. 63:102–110, 2004. © 2004 Wiley‐Liss, Inc.
Cryo‐sectioning and chemical‐fixing ultramicrotomy techniques for imaging rubber latex particle morphology
Authors: Subramaniam Nadaraja , Simpson Anne , Monteiro Michael J. , Shaffer Olga , Fellows Christopher M. , Gilbert Robert G.
Published: January 2004

Two methods adapted from biological microscopy are described for a new application in imaging the morphology of rubbery latex particles. In the first method, a drop of latex is frozen in liquid nitrogen, sectioned with a diamond knife and vapour‐stained with osmium tetroxide, then viewed by transmission electron microscopy. When applied to latexes made by emulsion polymerization of methyl methacrylate in a natural rubber latex seed, inclusions are clearly visible. A chemical fixation method is then described for imaging the morphology of such rubbery latex particles. Glutaraldehyde is added to the latex, followed by osmium tetroxide. The sample is then dehydrated in ethanol, epoxy resin added, and the sample cured, ultramicrotomed, and imaged with transmission electron microscopy. An inclusion morphology is again clearly seen. Microsc. Res. Tech. 63:111–114, 2004. © 2004 Wiley‐Liss, Inc.
Imaging the cell surface: Argon sputtering to expose inner cell structures
Authors: De Stasio Gelsomina , Frazer Bradley H. , Girasole Marco , Wiese Lisa M. , Krasnowska Ewa K. , Greco Giulia , Serafino Annalucia , Parasassi Tiziana
Published: January 2004

Established microscopies such as Scanning Electron Microscopy (SEM) and more recent developments such as Atomic Force Microscopy (AFM) and X‐ray Photo‐Electron Emission spectroMicroscopy (X‐PEEM) can only image the sample surface. We present an argon sputtering method able to progressively expose inner cell structures without apparent damage. By varying the sputtering time, the structure of cell cytoskeleton, vesicles, mitochondria, nuclear membrane, and nucleoli can be imaged. We compared images obtained with confocal fluorescence microscopy, transmission electron microscopy (TEM), SEM, and X‐PEEM on similar samples after argon sputtering, then confirmed the similarity of reference intracellular structures, including cytoskeleton fibers, cell‐cell and cell‐substrate adhesion structures, and secretory vesicles. We conclude that the sputtering method is a new valuable tool for surface sensitive microscopies. Microsc. Res. Tech. 63:115–121, 2004. © 2004 Wiley‐Liss, Inc.
Methods for determining the composition of nasal fluid by X‐ray microanalysis
Authors: Vanthanouvong Viengphet , Roomans Godfried M.
Published: January 2004

The nasal fluid is an easily accessible form of airway surface liquid. The objective of this study was to find a technically easy and reproducible method for sampling and analysis of this fluid. In a pilot study, several methods to carry out X‐ray microanalysis of sub‐microliter droplets were compared. Acceptable results were obtained with several of these methods (pipeting on filter paper or analysis of frozen‐hydrated droplets at low temperature). Nasal fluid was collected from the inferior turbinate with a micropipette after occlusion of a nostril for 5–10 minutes. Ion concentrations in nasal fluid from six control subjects were (in mM, mean ± standard error): sodium (Na) 127 ± 6, chloride (Cl) 140 ± 7, potassium (K) 27 ± 3, and calcium (Ca) 5 ± 1. This sampling method proved difficult to apply to cystic fibrosis (CF) patients because of the viscous quality of their nasal secretion. Therefore, an alternative method was devised. Sephadex G‐25, ion exchange beads were mounted on double‐sided tape, which was stuck on a filter paper as support. The filter paper was applied for 10 minutes to the nostril of a subject, and kept loosely in place. During the exposure period, the nasal fluid equilibrates with the beads. After removal of the filter paper with the beads from the nostril, the beads were rinsed with a hydrophobic volatile silicone oil to remove excess nasal fluid, dried, and analyzed. This method of collection is not cumbersome for the subject and gives results similar to those obtained by the direct collection method: Na 142 ± 28 mM, Cl 150 ± 36 mM, K 43 ± 10 mM (mean and standard error of four determinations). Small differences between the filter method and the bead method can be explained by the fact that the filter method measured total nasal fluid, whereas the bead method measures predominantly the fluid component. Subjects suffering from mild respiratory illness or rhinitis had higher values for Na, K, and Cl in their nasal fluid. Microsc. Res. Tech. 63:122–128, 2004. © 2004 Wiley‐Liss, Inc.
Nonlinear optical microscopy of cellular structures
Authors: Petrov G I , Saltiel S , Heathcote R D , Yakovlev V V
Published: January 2004

We propose a novel nonlinear optical spectroscopic technique H-CARS (Hyper Coherent Anti-Stokes Raman Spectroscopy) to allow imaging of biological structures in real time.
Influence of electron correlations on strong field ionization of calcium
Authors: Charron E , Sukharev M , Suzor-Weiner A
Published: January 2004

Non-perturbative time-dependent calculations of single and double ionization of a one-dimensional model of atomic calcium by short and intense laser pulses were performed at various wavelengths. The comparison of the probabilities calculated within a two-active electron (TAE) approach with those obtained using a single-active electron (SAE) approximation clearly demonstrates the crucial role played by the electronic correlation and by doubly excited states within this model, even for the formation of Ca+.
Scattering of a few-cycle laser pulse on a thin metal
layer : the effect of the carrier-envelope phase difference
Authors: Varró S
Published: January 2004

On the basis of classical electrodynamics the
reflection and transmission of a few-cycle femtosecond Ti:Sa laser
pulse impinging on a thin metal layer have been analysed. The
thickness of the layer was assumed to be much smaller than the
skin depth of the radiation field, and the metallic electrons were
represented by a surface current density. The interaction of the
electrons with a periodic lattice potential has also been taken
into account. The presence of this nonlinear potential leads to
the appearance of higher harmonics in the scattered spectra. A
formal exact solution has been given for the system of the coupled
Maxwell-Lorentz equations describing the dynamics of the surface
current and the radiation field. Besides, an analytic solution was
found in the strong field approximation for the Fourier components
of the reflected and transmitted radiation. In our analysis
particular attention has been paid to the role of the
carrier-envelope phase difference of the incoming few-cycle laser
pulse.
Laser spectroscopic methods for the characterization of open
and closed follicles
Authors: Otberg N , Richter H , Knuttel A , Schaefer H , Sterry W , Lademann J
Published: January 2004

Hair follicles have been assigned an increasingly
significant role in dermatopharmacology. Previous studies have
shown that the penetration of substances into the follicle depends
on its activity. Telogen follicles that were not producing sebum
were closed for follicular penetration. The present study uses
optical coherence tomography (OCT) to show that the orifices of
inactive follicles are blocked by plugs formed of corneocytes. The
follicular penetration of a fluorescent dye was analyzed by
cyanoacrylate surface biopsies in combination with laser scanning
microscopy. Surface exfoliation and cyanoacrylate surface peels
were used as a pre-treatment to remove the corneocyte plugs from
the follicular orifices and therefore to open up closed follicles.
It was shown that both procedures could increase the number of
open hair follicles significantly. The present experiments show
that OCT in combination with laser scanning microscopy is an
excellent non-invasive in vivo method for the investigation of
hair follicle properties and follicular penetration processes.
Zeros of eigenfunctions of a class of generalized second order differential operators on the Cantor set
Authors: Freiberg Uta , Löbus Jörg‐Uwe
Published: January 2004

Generalized second order differential operators of the form $ {d \over {d \mu}} {d \over {dx}} $ when μ is a selfsimilar measure whose support is the classical Cantor set are considered. The asymptotic distribution of the zeros of the eigenfunctions is determined. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The canonical solution operator of $ {\bar \partial } $ on weighted spaces with holomorphic coefficients
Authors: Knirsch Wolfgang
Published: January 2004

On weighted spaces with strictly plurisubharmonic weightfunctions the canonical solution operator of $ {\bar \partial } $ and the $ {\bar \partial } $‐Neumann operator are bounded. In this paper we find a class of strictly plurisubharmonic weightfunctions with certain growth conditions, so that they are Hilbert‐Schmidt operators between weighted spaces with different weightfunctions, if they are restricted to forms with holomorphic coefficients. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Nonlinear artificial boundary conditions for the Navier‐Stokes equations in an aperture domain
Authors: Nazarov Sergueï A. , Specovius‐Neugebauer Maria , Videman Juha H.
Published: January 2004

We consider the Dirichlet problem for the stationary Navier‐Stokes system in a plane domain Ω, with two angular outlets to infinity. It is known that, under appropriate decay and smallness assumptions, this problem admits solutions with main asymptotic terms in Jeffrey‐Hamel form. We will approach these solutions by constructing an approximating problem in the domain ΩR, which is the intersection of Ω with a sufficiently large circle. The main difficulty, in contrast to the corresponding linear problem, arises from the fact that the main asymptotic term is not known explicitly. Here, we create nonlinear, but local, artificial boundary conditions which involve second order differential operators on the truncation arcs. Unlike for the analogous three‐dimensional exterior problem, we are able to show the existence of weak solutions to the approximating problem without smoothness nor smallness assumptions. For small data, we prove that the solutions of the approximating problem are unique and regular. Finally, we reach the main goal of this work, i.e. we obtain error estimates in weighted Hölder spaces which are asymptotically precise as R tends to infinity. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Spaces of Bessel‐potential type and embeddings: the super‐limiting case
Authors: Neves Júlio S.
Published: January 2004

We consider Bessel‐potential spaces modelled upon Lorentz‐Karamata spaces and establish embedding theorems in the super‐limiting case. In addition, we refine a result due to Triebel, in the context of Bessel‐potential spaces, itself an improvement of the Brézis‐Wainger result (super‐limiting case) about the “almost Lipschitz continuity” of elements of H1+n/pp (ℝn). These results improve and extend results due to Edmunds, Gurka and Opic in the context of logarithmic Bessel potential spaces. We also give examples of embeddings of Besselpotential type spaces which are not of logarithmic type. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Stereologische Analyse und Modelierung von Objektverteilungen aus Schnittbildern
Authors: Gegner J. , Henninger C. , Öchsner A.
Published: January 2004

Das Gefüge von Werkstoffen kann mittels geeigneter Deskriptoren quantitativ charakterisiert werden. Eine solche Beschreibung erlaubt auch die Erstellung repräsentativer Modelle für die Simulation von Festkörperreaktionen. In der vorliegenden Arbeit werden diskontinuierliche Dualphasengefüge analysiert. Es wird ein mathematisches Korrekturverfahren zur Berechnung der wahren Größenverteilung kugelförmiger Objekte aus Schnittbildern abgeleitet. Ein Rechnerexperiment bestätigt die Anwendbarkeit dieser Methode. Nach entsprechender Analyse der Objektabstände können auch dreidimensionale Ersatzverteilungen berechnet werden. Ein stochastisches Suchverfahren, das auf einer Verbesserungsheuristik beruht, ermöglicht die Berücksichtigung höherer Nachbarschaftsordnungen. Das neue hybride Modellierungswerkzeug wird anhand eines praktischen Beispiels vorgestellt.
The influence of manganese addition on mechanical properties of commercial Al‐4Mg casting alloys
Authors: Bayram A.
Published: January 2004

The aim of this study was to investigate the mechanical properties of Al‐Mg‐Si alloys aged to peak hardness with different dispersoid volume fraction. It was found that the tensile strength increases with dispersoid content, for alloys having similar ductility. The effect of an increasingly triaxial stress state on a fracture strain above mentioned alloys were measured using a series of notched tensile specimens whose notch root radius of curvature was changed. The alloy ductility was found to increase with dispersoid content and root radius and to decrease with increased stress triaxiality. The fracture toughness of these alloys was determined as a function of dispersoid content and notch root radius of curvature. It was observed that the fracture toughness increased as the dispersoid content and the notch root radius increased. scanning electron microscope analysis of the fracture surfaces revealed that fracture mechanism was transgranular fracture with dimples formation. It is argued that optimum mechanical properties in these alloys can be achieved at about 0.5 % Mn content.
Die Anrisslebensdauerabschätzung unter Berücksichtigung des statistischen Größeneinflusses am Beispiel der AlMgSi0,7‐Legierung
Authors: Bazios I. , Gudladt H.‐J.
Published: January 2004

Die Abschätzung der Anrisslebensdauer wird unter Berücksichtigung des statistischen und technologischen Größeneinflusses im Rahmen eines analytischen Modells vorgestellt. Zur Verifikation dieses Modells werden Ergebnisse aus ein‐ und mehrstufigen Ermüdungsversuchen an ungekerbten und gekerbten Proben aus der mittelfesten AlMgSi‐Aluminiumlegierung AA6009 herangezogen.
Comparison of different methods for presenting variable amplitude loading fatigue results
Authors: Lagoda T. , Sonsino C. M.
Published: January 2004

This paper discusses eight methods for presenting fatigue test results for variable amplitude loading and their comparison with constant amplitude loading. While the maximum amplitude method compares constant and variable amplitude loading results by the Woehler and Gassner curves, all other seven methods try to transform the variable amplitude results into the Woehler curve by applying different equations. The advantage of the maximum amplitude method is the direct comparison of the maximum amplitude of the spectrum with the yield strength and with the high‐cycle fatigue strength, which is an important step in structural design. Among the other methods, the best results were obtained by following: most damaging, half damage and mean damage amplitudes. However, the presentation of constant and variable amplitude results by these methods in one scatter band is possible only when the real damage sum is close to D = 1.0.
Improvement of Mechanical Properties of Self Setting Calcium Phosphate Bone Cements Mixed With Different Metal Oxides
Authors: Gbureck U. , Spatz K. , Thull R.
Published: January 2004

Calcium phosphate cements (CPC), based on multicomponent powder mixtures of calcium orthophosphates with medium particle sizes in the region of 1 ‐ 20 μm, set isothermally in an aqueous environment to form hydroxyapatite (HA). HA cement reactants include tetracalcium phosphate (TTCP), tricalcium phosphate (TCP), dicalcium phosphate anhydrate (DCPA), dicalcium phosphate dihydrate (DCPD), monocalcium phosphate (MCPA) or octacalcium phosphate (OCP). The aim of this study was to improve the mechanical performance of TTCP / DCPA cement by adding several metal oxides to tetracalcium phosphate during the fabrication process. Cements based on tetracalcium phosphate mixed with silica or titanium oxide showed significant increases in compressive strength, approximately 80 ‐ 100 MPa, whilst no change in the mechanical behavior of CPC was observed if zirconia was added. X‐ray diffraction measurement confirmed the setting reaction of doped cements was similar to that of pure CPC. Low crystalline HA was found to be the main constituant of set cement; additional phases, such as calcium titanate or calcium zirconate, were not involved in the reaction. A mechanical reinforcement effect was thought to result from changes in the thermodynamic or kinetic solubilities of doped tetracalcium phosphates, this would lead to slower HA crystal formation and a more cross‐linked cement structure.
Novel Polylactide‐Based Release Systems for Local Antibiotic Therapies
Authors: Vogt S. , Kühn K.‐D. , Ege W. , Pawlik K. , Schnabelrauch M.
Published: January 2004

Antibiotic delivery systems based on biodegradable polymers have found considerable interest for the local therapy of bone infections. In this study polylactide based polymer and composite delivery systems for the release of gentamicin have been fabricated from poly‐L‐lactides and a poly(L‐lactide‐co‐D,L‐lactide) as well as biodegradable inorganic fillers (calcium hydrogen phosphate, calcium sulfate dihydrate). The in vitro release profiles of the polymer delivery systems were characterized by an initial burst release followed by a sustained release of small gentamicin amounts up to 3 weeks. In the composite delivery systems a loss of retardation was observed with an increasing content of inorganic filler material. It was found that the in situ complex formation of gentamicin by adding defined amounts of sodium dodecyl sulfate represents a valuable tool to overcome this problem and to modulate the release profile of the delivery systems in a wide range. Under in vitro conditions, calcium sulfate dihydrate containing delivery systems are rapidly degraded in aqueous medium within several months. Based on these results, the developed composite delivery systems are promising candidates for the efficient treatment of bone infections.
The Influence of Lipid Dipole Moment and Interfacial Water Structure on Protein Adsorption to Mixed Lipid Monolayers
Authors: Britt D. W. , Goodman Th. , Selle C.
Published: January 2004

Protein interactions with a heterogeneous surface, such as a two‐component lipid film, often deviate from simple additivity of the adsorption to the respective single component, “homogenous” films. This behavior was highlighted in previous research where adsorption of the negatively charged protein ferritin to mixed cationic / non‐ionic lipid films was greater than adsorption to either of the single component lipid films [Britt et al., Phys. Chem. Chem. Phys., 2, 4594‐4599, 2000]. Here we investigate mixing induced changes in lipid dipole moments and local water structure as factors leading to amplification of monolayer charge and subsequent enhanced protein adsorption to the mixed lipid films. Surface potential and Fourier transform infrared spectroscopy (FTIR) revealed a reduction in both lipid tilt angle and gauche defects in the mixtures that would lead to a greater contribution of lipid alkyl‐tail dipoles to the measured (normal) surface potential; however, as the orientation of the alkyl‐tail dipole is from water (negative) to air (positive) the greater dipolar contribution for reduced tilt angles actually opposes adsorption of a negatively charged protein from the subphase. FTIR also revealed a mixing induced disordering of water solvating the cationic lipid head group, suggesting water dipoles were less effective in screening charge, which in turn would enhance the electrostatic interactions between anionic protein and the mixed cationic / nonionic lipid film.
Interactions of Osteoblastic and Other Cells with Bioactive Glasses and Silica In Vitro and In Vivo
Authors: Silver I. A. , Erecinska M.
Published: January 2004

Responses of cells to the presence of 90‐150 μm particles of 3 bioactive glasses were compared with their reaction to non‐bioactive borosilicate glass and to a known tissue irritant, quartz/silica. Measurements were made in vitro and in vivo of changes of intra‐ and extracellular ion activities. Ion‐selective microelectrodes were used to determine intracellular pH, [Na+], [K+] and [Ca2+] in cultured rodent osteoblasts, fibroblasts and macrophages in contact with, or exposed to medium containing, Bioglass® 45S5, borosilicate glass and bioactive glasses 77S and 58S. The same materials were implanted in connective tissue in rabbit ear chambers and similar measurements were made in vivo. No significant differences were observed among the 3 cell‐types in their reactions, which were minimal, to the presence of the borosilicate and 58S and 77S glasses either in vivo or in vitro. However all cells were affected by interaction with Bioglass® 45S5 which caused significant alkalinisation at its extracellular contact sites and concomitant but smaller changes in internal pH. The latter were accompanied by significant increases in [K+], [Na+] and [Ca2+]. There was also hyperpolarisation of plasma membrane potential in fibroblasts and osteoblasts. In the presence of silica, macrophages showed marked and significant decreases in pH both at the contact zone and intracellularly. Among the cells used, osteoblasts showed higher and macrophages lower pH than fibroblasts when in contact with the test materials. Despite the known leaching of silicic acid from Bioglass® macrophages were not “activated” by its presence, but were by silica. It is concluded that materials developed as potential prostheses should also be examined for their ability to alter cellular metabolism.