bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metabolic Products of Microorganisms. Part 265. Prelactones C and B, oligoketides from Streptomyces producing concanamycins and bafilomycins
Authors: Bindseil Kai U. , Zeeck Axel 
Published: December 2004

AbstractPrelactones C (3) B (8) were isolated from the concanamycin‐producing Streptomyces sp. (strain Gö 22/15) and bafilomycin‐producing Streptomyces griseus (strain Tü 2599), respectively, by chemical screening methods. The constitution and relative configuration of 3 and 8 were established by one‐ and two‐dimensional NMR methods. The absolute configuration of 3 was determined using the Helmchen method and that of 8 by CD spectra. The structural properties and absolute configuration of these new δ‐lactones reveal strong similarities to the hemiacetal portion of the corresponding macrolide antibiotics. Their possible role in the early polyketide formation of unusual macrolactones is discussed.
Synthesis of Unique Ceramides and Cerebrosides Occurring in Human Epidermis
Authors: Müller Siliva , Schmidt Richard R. 
Published: December 2004

AbstractThe sphingolipids 1a, b and 2a, b which play important roles in epidermal barrier function, were synthesized by N‐acylation of C18‐sphingosine 3 and 1‐O‐glucosylated C18‐sphingosine 6, respectively, with ω‐acyloxy‐substituted fatty acids 4 and 5 (Scheme 1). These fatty acids were obtained from ω‐hydroxy‐substituted fatty acids 8 and 9 by esterification with linoleic acid (7). The C34‐fatty acid 8 was prepared as follows: C25‐Compound 18 was obtained by means of a Wittig reaction of C13‐aldehyde 13 with C12‐phosphonium salt 15 or of C12‐aldehyde 24 with C13‐phosphonium salt 21, respectively, and subseqent hydrogenation and O‐deprotection (Scheme 2). Alternatively, 8 was prepared via 30 by copper‐catalyzed coupling of C13‐alkyl halide 19 with the Grignard reagent derived from C12‐alkyl bromide 14 (Scheme 2). Oxidation of 18 to aldehyde 39 and Wittig reaction with C9‐phosphonium salt 41 furnished the desired ω‐hydroxy‐substituted fatty acid 8, after O‐deprotection (Scheme 3). Similarly, Wittig reaction of C11‐phosphonium salt 22 with C12‐aldehyde 24 furnished C23‐aldehyde 40, after hydrogenation, O‐deprotection, and oxidation; Wittig reaction with compound 41 and subsequent deprotection afforded the desired C32‐fatty and 9 (Scheme 3). an alternative strategy furnished compound 8 by a coupling reaction of alkyne 53 with ω‐bromo‐substitued fatty acid 52, obtained from compounds 24 and 47 by Wittig reaction, hydrogenation, and introduction of bromide (Scheme 4). Hydrogenation (Lindlar's catalyst) of the resulting C34‐alkyne 54 and deprotection furnished 8.
New Ecotoxicologically and Biogenetically Relevant Terpenes of the tropical green seaweed Caulerpa taxifolia which is invading the Mediterranean
Authors: Guerriero Antonio , Marchetti Federico , D'Ambrosio Michele , Senesi Sonia , Dini Fernando , Pietra Francesco 
Published: December 2004

AbstractThe tropical green seaweed Caulerpa taxifolia (VAHL) C. AGARDH (Caulerpales) which is invading the Mediterranean is shown to contain trace amounts of two further novel terpenes, 7,7‐C‐didehydro‐6‐hydroxy‐6,7‐dihydrocaulerpenyne (= (4S, 6S,1E)‐3‐[(Z)‐acetoxymethylidene]‐6‐hydroxy‐11‐methyl‐7‐methylidenedodeca‐1,10‐dien‐8‐yne‐1,4‐diyl diacetate; 3a) and taxifolione (= 6‐methylhept‐5‐en‐3‐yn‐2‐one; 4). The former is the most active of the toxins so far isolated from this seaweed, both as an in vitro inhibitor of the growth of marine bacteria and as a cytotoxic agent toward marine ciliate protists. This suggests a central ecotoxicological role for triacetate 3a as an adjuvant factor in the invasion of the Mediterranean by this seaweed. Moreover, the almost equally toxic 10,11 ‐epoxycaulerpenyne (2) which is scarcely available from Nature for bioassays can now be obtained by peroxy‐acid epoxidation of caulerpenyne (1), along with the 6,7‐epoxycaulerpenynes 6b and 6a. The latter are very labile, 6a giving triacetate 3a, suggesting epoxides to be late biogenetic intermediates in C. taxifolia.
Tetrakis[(4S)‐4‐phenyloxazolidin‐2‐one]dirhodium(II) and Its Catalytic Applications for Metal Carbene Transformations
Authors: Doyle Michael P. , Winchester William R. , Protopopova Marina N. , Müller Paul , Bernardinelli Gérald , Ene Doina , Motallebi Sharokh 
Published: December 2004

AbstractThe synthesis and X‐ray structure of the binuclear complex tetrakis[(4S)‐4‐phenyloxazolidin‐2‐one]‐dirhodium(II) ([Rh2{(4S)‐phox}4]) are reported. Structure‐selectivity comparisons are made for typical metal carbene transformations, such as inter‐ and intramolecular cyclopropane formation, intermolecular cyclopropene formation and intramolecular C–H insertions of diazoacetates and diazoacetamides. The enantioselectivity achieved in the [Rh2{(4S)‐phox}4]‐catalyzed reactions is intermediate between that of [Rh2{(5S)‐mepy}4] and [Rh2{(4R)‐bnox}4], which were described previously (mepy = methyl 5‐oxopyrrolidine‐2‐carboxylate; bnox = 4‐benzyloxazolidin‐2‐one). In contrast to other catalyzed intermolecular cyclopropane formations, those using [Rh2{(4S)‐phox}4] result preferentially in formation of the cis‐cyclopropane.
(6R,9′Z)‐Neoxanthin: Synthese, Schmelzverhalten, Spektren und Konformationsberechnungen
Authors: Baumeler Andreas , Zerbe Oliver , Kunz Roland , Eugster Conrad Hans 
Published: December 2004

(6R,9′Z)‐Neoxanthin: Synthesis, Physical Properties, Spectra, and Calculations of Its Conformation in SolutionThe synthesis of pure and crystalline (9′Z)‐neoxanthin (6) is described. MnO2 Oxidation of (9Z)‐C15‐alcohol 7 at room temperature produces a mixture 8/9 of (9Z)‐ and (9E)‐aldehydes. Predominant formation of the required (9Z)‐aldehyde 8 is achieved by performing the oxidation at − 10°. Condensation of 8 with the mono‐Li salt of the symmetrical C10‐diphosphonate 10 gave the (9Z)‐C25‐monophosphonate 11. The Wittig‐Horner condensation of 10 with the allenic C15‐aldehyde 1b, under selected conditions allows the preparation of pure and crystalline (9′Z)‐15,15′‐didehydroneoxanthin (12) and, after subsequent semireduction, of crystalline (15Z,9′Z)‐neoxanthin (13). Thermal isomerisation of a AcOEt solution of 13 at 95° yields preferentially (9′Z)‐neoxanthin (6). Our crystalline sample shows the highest ϵ‐values in the UV/VIS spectra ever recorded. The CD spectra display a pronounced similarity with those of corresponding violaxanthin isomers. In contrast to the (all‐E)‐isomer 5, (9′Z)‐neoxanthin undergoes very little isomerisation when heated to its melting point. For comparison purposes, a crystalline probe of 6 is also isolated from lawn mowings. Extensive 1H‐and 13C‐NMR investigations at 600 MHz of a (D6)benzene solution using 2D‐experiments such as COSY, TOCSY, ROESY, HMBC, and HMQC techniques permit the unambiguous assignment of all signals. Force‐field calculations of a model system of 6 indicate the presence of several interconverting conformers of the violaxanthin end group, 66% of which possess a pseudoequatorial and 34% a pseudoaxial OHC(3′). The torsion angle (ω1) around the C(6′)C(7′) bond, known to be of prime importance for the shape of the CD spectra, varies with values of 87° for 55% and 263° for 45% of the molecules. Therefore, the molecules clearly display a preference for the ‘syn’‐position of the C(7′)C(8′) bond and the epoxy group. Unexpectedly, the double bonds of C(7′)C(8′) and C(9′)C(10′) are not coplanar. The deviation amounts to ± 20°, both in the ‘syn’ ‐ and the ‘anti’‐conformation.
Synthesis, Base Pairing, and Structural Transitions of Oligodeoxyribonucleotides Containing 8‐Aza‐2′‐deoxyguanosine
Authors: Seela Frank , Lampe Sigrid 
Published: December 2004

AbstractThe synthesis of oligonucleotides containing 8‐aza‐2′‐deoxyguanosine (z8Gd; 1) or its N8‐regioisomer z8Gd* (2) instead of 2′‐deoxyguanosine (Gd) is described. For this purpose, the NH2 group of 1 and 2 was protected with a (dimethylamino)methylidene residue (→5, 6), a 4,4′‐dimethoxytrityl group was introduced at 5′‐OH (→ 7, 8), and the phosphonates 3a and 4 as well as the phosphoramidite 3b were prepared. These building blocks were used in solid‐phase oligonucleotide synthesis. The oligonucleotides were characterized by enzymatic hydrolysis and melting curves (Tm values). The thermodynamic data of the oligomers 12–15 indicate that duplexes were stabilized when 1 was replacing Gd. The aggregation of d(T‐G‐G‐G‐G‐T) (18) was studied by RP 18 HPLC, gel electrophoresis and CD spectroscopy and compared with that of oligonucleotides containing an increasing number of z8Gd residues instead of Gd. Similarly to [d(C‐G)]3 (12a), the hexamer d(C‐z8G‐C‐z8G‐C‐G) (14) underwent salt‐dependent B‐Z transition.
Über die Diamin‐oxydase der Smegmabazillen
Authors: Roulet F. , Zeller E. A. 
Published: December 2004

Abstract1. Die Bakterien des in der vorliegenden Arbeit verwendeten Stammes von Mycobact. smegmatis oxydieren Putrescin, Agmatin, Spermin, Cadaverin und Histamin. Die Oxydationsgeschwindigkeit nimmt in der angegebenen Reihenfolge ab. Als Reaktionsprodukte entstehen Ammoniak, Peroxyd und Kohlendioxyd.
Matrix elements of general configuration of nonorthogonalized orbitals in state with definite spin
Authors: Kaplan I. G. , Rodimova O. B. 
Published: December 2004

AbstractThe expressions for matrix elements of spin‐independent operators F and G with the use of Young operators are obtained in the case of arbitrary nonorthogonalized orbital configuration, including both singly and doubly filled orbitals and corresponding to the definite value of total spin. The formulas obtained do not require a preliminary construction of linear combinations of determinants and turn into known Löwdin formulas in the particular case of fully antisymmetric spatial states.
Oscillator and hydrogenic matrix elements by operator algebra
Authors: Witschel W. , Grosswendt B. 
Published: December 2004

AbstractOccupation number representation of the two‐dimensional harmonic oscillator and some operator formulae are used in a simple algebraic derivation of complicated integrals. The calculation of full oscillator‐ and radial integrals of r̂w and exp (\documentclass{article}\pagestyle{empty}\begin{document}$ (iw\hat{\varphi})$\end{document}), where w is an arbitrary positive or negative integer, are performed by an integral transform, leading to a generalized Gauss matrix element. Thus it is possible, because of the back transformation, to derive from one generalized Gauss matrix element all matrix elements which are permitted by the selection rules. Some integrals of r̂w and exp (\documentclass{article}\pagestyle{empty}\begin{document}$ (iw\hat{\varphi})$\end{document}), Laguerre polynomials, and Bessel functions are completely new. For the already known integrals, the mathematical labour is considerably reduced. The relation between the two‐dimensional oscillator and the hydrogen atom and their angular momentum properties are discussed. A survey on the various methods applied to the oscillator problem, from complex integration to noncompact Lie groups, and a comprehensive bibliography on this important spectroscopic field are given.
Long‐ and intermediate‐range interaction in three lowest sigma states of the HeH+ ion
Authors: Kołos W. 
Published: December 2004

AbstractAccurate variational energies have been calculated for three lowest sigma states of the HeH+ ion. This includes the ground state (5 ≤ R ≤ 9 a.u.) which dissociates into He + H+, as well as the A 1Σ+ state (4 ≤ R ≤ 10) and the a 3Σ+ state (3 ≤ R ≤ 10) which both dissociate into He+ + H. The variational results are compared with those obtained using a perturbation theory expansion.
Applications of a quantum virial theorem to kronig and penney's model and to a diatomic molecule in static approximation
Authors: Weislinger Edmond , Olivier Gabriel 
Published: December 2004

AbstractKronig and Penney's model is used to test a new formulation of quantum virial theorem for periodic systems. It is shown that the corrective term to the usual formulation of the virial theorem corresponding to boundary conditions is of importance and gives correct energy values for the system. Application of the virial theorem to a diatomic molecule also shows an important boundary condition correction if the distance of the nuclei is slightly different from equilibrium position, in accordance with the above correction.
A new energy decomposition scheme for molecular interactions within the Hartree‐Fock approximation
Authors: Kitaura Kazuo , Morokuma Keiji 
Published: December 2004

AbstractA new method is proposed for the analysis of components of molecular interaction energy within the Hartree‐Fock approximation. The Hartree‐Fock molecular orbitals of the isolated molecules are used as the basis for the construction of Fock matrix of the supermolecule. Then certain blocks of this matrix are set to zero subject to specify boundary conditions of the supermolecule molecular orbitals, and the resultant matrix is diagonalized iteratively to obtain the desired energy components. This method can be considered as an extension of our previous method, but has an advantage in the explicit definition of the charge transfer energy, placing it on an equal footing with the exchange and polarization terms. The new method is compared with existing perturbation methods, and is also applied to the energy and electron density decomposition of (H2O)2.
Nursing home staff attitudes towards residents with dementia: strain and satisfaction with work
Authors: Brodaty Henry , Draper Brian , Low Lee‐Fay 
Published: December 2004

Background.  Occupational and resident characteristics affect levels of staff stress and satisfaction in nursing homes, and levels of staff turnover are high. Working with more cognitively impaired residents, especially on day shift, is associated with high levels of stress in nursing home staff. Workload is highly predictive of the experience of burden and job pressure, while these outcomes vary according to whether staff work full‐ or part‐time.Aims.  To investigate the attitudes of nursing home staff towards residents, strain related to dementia care and satisfaction with work and their associations with demographic, occupational and behavioural disturbance in the home.Methods.  A cross‐sectional design was adopted, using a self‐completion questionnaire survey of 253 nursing home staff from 12 nursing homes in Sydney's eastern suburbs, and behavioural assessment of all 647 residents from 11 of the 12 homes. Staff attitudes and strain were measured using the Swedish Strain in Nursing Care Assessment Scale and satisfaction using the Swedish Satisfaction with Nursing Care and Work Assessment Scale.Results.  Staff members’ five most prevalent perceptions of residents with dementia were that they are anxious, have little control over their difficult behaviour, are unpredictable, lonely and frightened/vulnerable. The five attributes staff found most difficult to cope with were being aggressive/hostile, having little control over their difficult behaviour, being stubborn/resistive, deliberately difficult, and unpredictable. Although 91% of staff reported that they were happy in their job, a quarter reported that residents provided no job satisfaction. The five satisfaction statements most agreed with were ‘The patients/residents at work nearly always receive good care’, ‘It is important to try and enter into the way patients experience what happens to them’, ‘Relatives are given enough information about care and treatment’, ‘I enjoy my current work situation’ and ‘Our work organisation is good’. There were significant differences between homes in levels of strain related to dementia care that were not accounted for by the level of behavioural disturbance.Conclusions.  Nursing home staff tended to perceive residents in more negative than positive ways. Staff were generally satisfied with their work. Factors other than resident behavioural disturbance are important influences in nursing staff strain.
Neoadjuvant flutamide monotherapy for locally confined prostate cancer
Authors: YOSHIMURA KOJI , SUMIYOSHI YOSHITERU , HASHIMURA TAKAYUKI , UEDA TOMOHIRO , KAMIRYO YORIAKI , YAMAMOTO AKIHIRO , ARAI YOICHI 
Published: December 2004

AbstractBackground: We compared the clinical effects and impact on quality of life (QOL) of patients who received a 3‐month course of flutamide monotherapy before radical prostatectomy with those who received a 3‐month course of luteinizing hormone‐releasing hormone (LHRH) agonist monotherapy.Methods: Thirty‐seven patients with non‐metastatic prostate cancer were enrolled in this study (19, flutamide; 18, LHRH agonist). The rates of change of serum prostate‐specific antigen (PSA) and testosterone levels, downsizing of prostate volume, the rate of organ confined disease, adverse effects and perioperative scores measured using the European Organization for Research and Treatment of Cancer Prostate Cancer Quality of Life Questionnaire (EORTC‐P) and the Sapporo Medical University Sexual Function Questionnaire (SMUF) were analyzed.Results: At radical prostatectomy, pathological variables were not significantly different in the two groups. Serum testosterone level was significantly higher (mean 359.2 compared to 10.5, P < 0.001), complete response rate of PSA (13% compared to 57%, P = 0.028) and rate of downsizing of prostate volume (mean, −17.7% compared to −35.4%, P = 0.038) were significantly lower in the flutamide group than in the LHRH group. After neoadjuvant hormone therapy, the scores on the sexual problem domain of EORTC‐P (P = 0.033) and sexual desire score of SMUF (P = 0.021) were significantly higher in the flutamide group than in the LHRH group. At a median follow‐up of 34 months after prostatectomy, biochemical failure‐free survival rate in the flutamide group did not differ from that in the LHRH group.Conclusion: This study suggests that flutamide monotherapy can be an acceptable modality as an option for neoadjuvant hormone therapy.
Histopathological analysis of angiogenic factors in renal cell carcinoma
Authors: YAGASAKI HIROKI , KAWATA NOZOMU , TAKIMOTO YUKIE , NEMOTO NORIMICHI 
Published: December 2004

AbstractAim: The present study was carried out to clarify whether a histopathological analysis of vascular endothelial growth factor (VEGF), transforming growth factor‐β1 (TGF‐β1) and matrix metalloproteinase 2 (MMP‐2) can help predict the outcome of renal cell carcinoma (RCC). We examined the expression of VEGF, TGF‐β1 and MMP‐2 in a large series of RCC with a long follow‐up, based on histopathological factors and survival.Methods: Immunostaining for VEGF, TGF‐β1 and MMP‐2 was performed on formalin‐fixed, paraffin‐embedded tissue sections from 84 patients with RCC who underwent nephrectomy at our institution between 1985 to 2000. The microvessel density (MVD) of tumor tissue was measured after it immunohistochemically stained with CD105 (Endoglin) monoclonal antibody.Results: A significant association was observed in the expression of VEGF and TGF‐β1 regarding the stage (P < 0.01, P < 0.01), nuclear grade (P < 0.01, P < 0.01) and MVD (P < 0.001, P < 0.001), respectively. However, no correlation was found among the results of MMP‐2, nuclear grade and MVD. A multivariate analysis demonstrated both the nuclear grade and MVD to be independent prognostic factors.Conclusion: Our results suggested that the expression of both VEGF and/or TGF‐β1 can be useful predictive prognostic factors RCC. In addition, a multivariate analysis demonstrated MVD to be an independent prognostic factor of RCC.
Indirect Selection for Root Development of White Clover and Implications for Drought Tolerance
Authors: Annicchiarico P. , Piano E. 
Published: December 2004

AbstractImproving white clover drought tolerance by selecting for more developed roots is controversial, labour‐consuming and complicated by the adventitious root system. This study aimed at assessing: (i) the value of thicker stolons as an indirect selection criterion for increasing root development, (ii) the relationship between root development and drought tolerance, and (iii) the consistency of population response for root and shoot traits between swards derived from seedlings or stolon cuttings. Thick‐ and thin‐stolon populations obtained by one cycle of divergent phenotypic selection within one ladino landrace, and one ladino natural population, were evaluated in metal containers (0.55 m × 0.12 m × 0.75 m deep) in a 1‐year experiment including vegetative material (seedling or stolon cutting) and drought stress (absent or present) as additional factors. Aerial dry weight (DW) was also assessed across two summer harvests under irrigated and rainfed field conditions for the thick‐stolon selection, two breeding populations selected from the same landrace regardless of stolon thickness, and the drought‐tolerant ladino ‘Brown Loam Synthetic no. 2’. The thick‐stolon selection had greater root DW (+21 %) than the thin‐stolon selection besides thicker stolons (+23 %). The natural population combined thinnest stolons with lowest root DW. Differences between populations were consistent across vegetative material. Primary and adventitious root systems did not differ for root DW in deeper soil horizons (>23 cm), above‐ground biomass and its reduction due to drought stress. Root DW increased under stress, particularly in deeper horizons. Aerial DW variation among populations evened up or narrowed much under stress, with no cross‐over interaction leading to an advantage of thick‐stolon material or ‘Brown‐Loam Synthetic no. 2’.
Genotypic Variation in Wheat in Response to Water Stress and Abscisic Acid‐Induced Accumulation of Osmolytes in Developing Grains
Authors: Nayyar H. , Walia D. P. 
Published: December 2004

AbstractTwo wheat genotypes differing in water stress sensitivity (C306, relatively tolerant; HD2329, relatively susceptible) were water stressed during early grain filling by withholding water for 7 days at watery‐ripe (WR) stage and examined for water status, abscisic acid (ABA) and osmolytes in grains as well as in flag leaf (FL). Both the genotypes differed significantly from each other in endogenous levels of ABA, proline, glycine betaine, total soluble sugars, reducing sugars, sucrose and potassium. The tolerant genotype showed higher content of ABA, proline, glycine betaine, total sugars, reducing sugars and had higher water content in its FL and grains than the susceptible genotype, which contained more of glycine beatine and potassium but had lower ABA and water content in its FL and grains. Although carbohydrates constituted the major amount of all the solutes, proline and glycine betaine increased manifold during stress. Exogenous application of 2 μm ABA at 5 days after anthesis to FL of stressed plants increased the endogenous content of ABA, accelerated the accumulation of osmolytes, improved the water status of FL and grains that resulted in higher grain weight, especially in the susceptible genotype. Differential response of contrasting wheat genotypes to water stress may be governed by ABA‐dependent solute accumulation in grains and FL.