bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional Analysis of the Simian Immunodeficiency Virus Vpx Protein: Identification of Packaging Determinants and a Novel Nuclear Targeting Domain
Authors: Mahalingam Sundarasamy , Van Tine Brian , Santiago Mario L. , Gao Feng , Shaw George M. , Hahn Beatrice H.
Published: July 2002

Thevpxgene products of human immunodeficiency virus type 2 (HIV-2) and of the closely related simian immunodeficiency viruses from sooty mangabeys (SIVsm) and macaques (SIVmac) comprise a 112-amino-acid virion-associated protein that is critical for efficient virus replication in nondividing cells such as macrophages. When expressed in the absence of other viral proteins, Vpx localizes to the nuclear membrane as well as to the nucleus; however, in the context of virus replication Vpx is packaged into virions via interaction with the p6 domain of the Gag precursor polyprotein (p55gag). To identify the domains essential for virion incorporation and nuclear localization, site-directed mutations were introduced into thevpxgene of SIVsmPBj1.9 and functionally analyzed. Our results show that (i) mutation of two highly conserved L74 and I75 residues impaired both virion incorporation and nuclear localization of Vpx; (ii) substitution of conserved H82, G86, C87, P103, and P106 residues impaired Vpx nuclear localization but not virion incorporation; (iii) mutations of conserved Y66, Y69, and Y71 residues impaired virion incorporation but not the translocation of Vpx to the nucleus; and (iv) a mutation at E30 (predicted to disrupt an N-terminal α-helix) had no effect on either virion incorporation or nuclear localization of Vpx. Importantly, mutations in Vpx which impaired nuclear localization also reduced virus replication in macaque macrophages, suggesting an important role of the carboxyl terminus of Vpx in nuclear translocation of the viral preintegration complex. Analyzing this domain in greater detail, we identified a 26-amino-acid (aa 60 to 85) fragment that was sufficient to mediate the transport of a heterologous protein (green fluorescent protein [GFP]) to the nucleus. Taken together, these results indicate that virion incorporation and nuclear localization are encoded by two partially overlapping domains in the C-terminus of Vpx (aa 60 to 112). The identification of a novel 26-amino-acid nuclear targeting domain provides a new tool to investigate the nuclear import of the HIV-2/SIV preintegration complex.
Detailed Analysis of the Requirements of Hepatitis A Virus Internal Ribosome Entry Segment for the Eukaryotic Initiation Factor Complex eIF4F
Authors: Borman Andrew M. , Michel Yanne M. , Kean Katherine M.
Published: July 2002

The hepatitis A virus (HAV) internal ribosome entry segment (IRES) is unique among the picornavirus IRESs in that it is inactive in the presence of either the entero- and rhinovirus 2A or aphthovirus Lb proteinases. Since these proteinases both cleave eukaryotic initiation factor 4G (eIF4G) and HAV IRES activity could be rescued in vitro by addition of eIF4F to proteinase-treated extracts, it was concluded that the HAV IRES requires eIF4F containing intact eIF4G. Here, we show that the inability of the HAV IRES to function with cleaved eIF4G cannot be attributed to inefficient binding of the cleaved form of eIF4G by the HAV IRES. Indeed, the binding of both intact eIF4F and the C-terminal cleavage product of eIF4G to the HAV IRES was virtually indistinguishable from their binding to the encephalomyocarditis virus IRES, as assessed by UV cross-linking and filter retention assays. Rather, we show that HAV IRES activity requires, either directly or indirectly, components of the eIF4F complex which interact with the N-terminal fragment of eIF4G. Effectively, HAV IRES activity, but not that of the human rhinovirus IRES, was sensitive to the rotavirus nonstructural protein NSP3 [which displaces poly(A)-binding protein from the eIF4F complex], to recombinant eIF4E-binding protein (which prevents the association of the cap binding protein eIF4E with eIF4G), and to cap analogue.
Molecular Determinants of Virulence, Cell Tropism, and Pathogenic Phenotype of Infectious Bursal Disease Virus
Authors: Brandt Meggin , Yao Kun , Liu Meihong , Heckert Robert A. , Vakharia Vikram N.
Published: July 2002

Infectious bursal disease viruses (IBDVs), belonging to the family
Birnaviridae
, exhibit a wide range of immunosuppressive potential, pathogenicity, and virulence for chickens. The genomic segment A encodes all the structural (VP2, VP4, and VP3) and nonstructural proteins, whereas segment B encodes the viral RNA-dependent RNA polymerase (VP1). To identify the molecular determinants for the virulence, pathogenic phenotype, and cell tropism of IBDV, we prepared full-length cDNA clones of a virulent strain, Irwin Moulthrop (IM), and constructed several chimeric cDNA clones of segments A and B between the attenuated vaccine strain (D78) and the virulent IM or GLS variant strain. Using the cRNA-based reverse-genetics system developed for IBDV, we generated five chimeric viruses after transfection by electroporation procedures in Vero or chicken embryo fibroblast (CEF) cells, one of which was recovered after propagation in embryonated eggs. To evaluate the characteristics of the recovered viruses in vivo, we inoculated 3-week-old chickens with D78, IM, GLS, or chimeric viruses and analyzed their bursae for pathological lesions 3 days postinfection. Viruses in which VP4, VP4-VP3, and VP1 coding sequences of the virulent strain IM were substituted for the corresponding region in the vaccine strain failed to induce hemorrhagic lesions in the bursa. In contrast, viruses in which the VP2 coding region of the vaccine strain was replaced with the variant GLS or virulent IM strain caused rapid bursal atrophy or hemorrhagic lesions in the bursa, as seen with the variant or classical virulent strain, respectively. These results show that the virulence and pathogenic-phenotype markers of IBDV reside in VP2. Moreover, one of the chimeric viruses containing VP2 sequences of the virulent strain could not be recovered in Vero or CEF cells but was recovered in embryonated eggs, suggesting that VP2 contains the determinants for cell tropism. Similarly, one of the chimeric viruses containing the VP1 segment of the virulent strain could not be recovered in Vero cells but was recovered in CEF cells, suggesting that VP1 contains the determinants for cell-specific replication in Vero cells. By comparing the deduced amino acid sequences of the D78 and IM strains and their reactivities with monoclonal antibody 21, which binds specifically to virulent IBDV, the putative amino acids involved in virulence and cell tropism were identified. Our results indicate that residues Gln at position 253 (Gln253), Asp279, and Ala284 of VP2 are involved in the virulence, cell tropism, and pathogenic phenotype of virulent IBDV.
In Vitro Selection and Characterization of Influenza A (A/N9) Virus Variants Resistant to a Novel Neuraminidase Inhibitor, A-315675
Authors: Molla Akhteruzzaman , Kati Warren , Carrick Robert , Steffy Kevin , Shi Yan , Montgomery Debra , Gusick Nanette , Stoll Vincent S. , Stewart Kent D. , Ng Teresa I. , Maring Clarence , Kempf Dale J. , Kohlbrenner William
Published: July 2002

With the recent introduction of neuraminidase (NA) inhibitors into clinical practice for the treatment of influenza virus infections, considerable attention has been focused on the potential for resistance development and cross-resistance between different agents from this class. A-315675 is a novel influenza virus NA inhibitor that has potent enzyme activity and is highly active in cell culture against a variety of strains of influenza A and B viruses. To further assess the therapeutic potential of this compound, in vitro resistance studies have been conducted and a comparative assessment has been made relative to oseltamivir carboxylate. The development of viral resistance to A-315675 was studied by in vitro serial passage of influenza A/N9 virus strains grown in MDCK cells in the presence of increasing concentrations of A-315675. Parallel passaging experiments were conducted with oseltamivir carboxylate, the active form of a currently marketed oral agent for the treatment of influenza virus infections. Passage experiments with A-315675 identified a variant at passage 8 that was 60-fold less susceptible to the compound. Sequencing of the viral population identified an E119D mutation in the NA gene, but no mutations were observed in the hemagglutinin (HA) gene. However, by passage 10 (2.56 μM A-315675), two mutations (R233K, S339P) in the HA gene appeared in addition to the E119D mutation in the NA gene, resulting in a 310-fold-lower susceptibility to A-315675. Further passaging at higher drug concentrations had no effect on the generation of further NA or HA mutations (20.5 μM A-315675). This P15 virus displayed 355-fold-lower susceptibility to A-315675 and >175-fold-lower susceptibility to zanamivir than did wild-type virus, but it retained a high degree of susceptibility to oseltamivir carboxylate. By comparison, virus variants recovered from passaging against oseltamivir carboxylate (passage 14) harbored an E119V mutation and displayed a 6,000-fold-lower susceptibility to oseltamivir carboxylate and a 175-fold-lower susceptibility to zanamivir than did wild-type virus. Interestingly, this mutant still retained susceptibility to A-315675 (42-fold loss). This suggests that cross-resistance between A-315675- and oseltamivir carboxylate-selected variants in vitro is minimal.
Kunjin Virus Replicon Vaccine Vectors Induce Protective CD8+T-Cell Immunity
Authors: Anraku Itaru , Harvey Tracey J. , Linedale Richard , Gardner Joy , Harrich David , Suhrbier Andreas , Khromykh Alexander A.
Published: July 2002

The ability of self-replicating RNA (replicon) vaccine vectors derived from the Australian flavivirus Kunjin (KUN) to induce protective αβ CD8+T-cell responses was examined. KUN replicons encoding a model immunogen were delivered by three different vaccine modalities: (i) as naked RNA transcribed in vitro, (ii) as plasmid DNA constructed to allow in vivo transcription of replicon RNA by cellular RNA polymerase II (DNA based), and (iii) as replicon RNA encapsidated into virus-like particles. A single immunization with any of these KUN replicon vaccines induced CD8+T-cell responses at levels comparable to those induced by recombinant vaccinia virus encoding the same immunogen. Immunization with only 0.1 μg of DNA-based KUN replicons elicited CD8+T-cell responses similar to those seen after immunization with 100 μg of a conventional DNA vaccine. Naked RNA immunization with KUN replicons also protected mice against challenges with recombinant vaccinia virus and B16 tumor cells. These results demonstrate the value of KUN replicon vectors for inducing protective antiviral and anticancer CD8+T-cell responses.
Tat-Vaccinated Macaques Do Not Control Simian Immunodeficiency Virus SIVmac239 Replication
Authors: Allen Todd M. , Mortara Lorenzo , Mothé Bianca R. , Liebl Max , Jing Peicheng , Calore Briana , Piekarczyk Marian , Ruddersdorf Richard , O'Connor David H. , Wang X. , Wang Chenxi , Allison David B. , Altman John D. , Sette Alessandro , Desrosiers Ronald C. , Sutter Gerd , Watkins David I.
Published: July 2002

The regulatory proteins of human immunodeficiency virus may represent important vaccine targets. Here we assessed the role of Tat-specific cytotoxic T lymphocytes (CTL) in controlling pathogenic simian immunodeficiency virus SIVmac239 replication after using a DNA-prime, vaccinia virus Ankara-boost vaccine regimen. Despite the induction of Tat-specific CTL, there was no significant reduction in either peak or viral set point compared to that of controls.
The Least Motion Principle, Concertedness and the Mechanisms of Pericyclic Reactions. A Similarity Approach
Authors: Ponec Robert , Strnad Martin
Published: July 2002

The recently proposed topological criterion of concertedness was complemented by a procedure allowing the variational determination of reaction paths characterizing the detailed course of bonding reorganization in modified More O'Ferrall diagrams. The proposed approach, allowing the simple unequivocal classification of reaction mechanisms is demonstrated with examples of several selected pericyclic reactions, both forbidden and allowed. The mechanistic conclusions obtained are in qualitative agreement with the predictions based on expectations from Woodward-Hoffmann rules and independent theoretical calculations.
Effect of Random Errors and Bias of Isobaric Equilibrium x, y and t Data of LiquidVapour Binary Systemson the Calculated Number of Theoretical Plates of a Rectification Column
Authors: Dojčanský Ján , Bafrncová Soňa , Surový Július
Published: July 2002

The effect of random errors and bias of temperature and phase composition data in the isobaric L-G equilibrium on the calculated number of theoretical plates of a continuously working rectification column at various reflux ratios was investigated. Five model binary systems exhibiting different behaviour and relative volatility were used.
MNDO and ab initio Calculations of Methyl 2-Lithioisobutyrate and Its Solvates and Aggregates
Authors: Dybal Jiří , Kříž Jaroslav
Published: July 2002

Ab initio and semiempirical (MNDO) molecular orbital calculations are reported of the energies, charge distributions, and geometries of methyl 2-lithioisobutyrate (LIMIB) used as a model of the propagation centre in the anionic polymerization of (meth)acrylates. Two stable forms energetically not very differing were found, one being near to the enolate, the other nearer to the keto form, both at the MNDO and 6-31G** levels. Stabilization energies and geometries of the dimer, trimer, and tetramer aggregates of LIMIB and of its solvates with dimethyl ether molecules were calculated at the MNDO level. These results agree with our earlier experimental findings obtained with the tetrahydrofuran solutions of LIMIB.
The Role of MoO3 and Fe2O3 in the Thermal Decomposition of Ammonium Perchlorate
Authors: Halawy Samih A. , Mohamed Mohamed A.
Published: July 2002

The effect of addition of MoO3 and Fe2O3 as well as mixtures of the two oxides (calcined in air at 500 °C) on the thermal decomposition of ammonium perchlorate (AP) was studied using thermogravimetry (TGA) and derivative thermogravimetric analysis (DTG). The catalysts calcined at 500 °C were characterized using TPR, XPS and XRD techniques. The surface area of the catalysts was determined by means of the conventional BET method. The results are discussed in terms of the recently published mechanism in which nitryl perchlorate is supposed as an intermediate in the thermal decomposition of pure AP. The correlation between the surface area and activity of the catalysts in the thermal decomposition of AP has been done. The activation energy (∆E) for non-catalyzed and catalyzed high-temperature thermal decomposition of AP were calculated from the TGA results using the Coats-Redfern equation.
Determination of Trace Concentrations of Aliphatic Amines in the Gas Phase after Preconcentration on a Solid Sorbent
Authors: Ventura Karel , Svobodová Kateřina , Dostál Miroslav , Churáček Jaroslav
Published: July 2002

The technique of trapping aliphatic amines from gaseous and liquid phases on solid polymeric organic sorbents followed by thermal desorption and quantitation by gas chromatography or, after conversion to fluorescent (UV) derivatives, by liquid chromatography was studied. The interaction of 8 primary aliphatic amines and 4 secondary amines with 3 sorbents, viz. Tenax GC, Chromosorb 103, and Separon SE, was examined. Analytical GC and HPLC procedures were developed for butylamine and subsequently tested on a C4 - C7 primary alkylamine mixture.
Axially Chiral Selectors of C2 Symmetry Bound to Silica: Synthesis and HPLC-Evaluation
Authors: Tichý Miloš , Holanová Jana , Starý Ivo , Stará Irena G. , Závada Jiří
Published: July 2002

Axially chiral biaryl stationary phases (CSPs) of C2 symmetry bound to 3-aminopropyl silica both by ionic and covalent bond were prepared. The separation effectivity of the CSPs so obtained was investigated using 2-acylamino alcohols and biaryl derivatives as analytes. Whereas ionically bound phases derived from biphenyl-2,2'-dicarboxylic or 2,2'-bipyridine-3,3'-dicarboxylic acids (CSP 1, 2, 3 and 4) generally exhibited good resolving performance for 2-acylamino alcohols, they were ineffective for biaryl derivatives. On the other hand, covalent CSPs showed poor selector properties with acylamino alcohols; the binaphthyl CSP 7 resolved some of the biaryl analytes. Phase CSP 6 was completely inactive toward all the compounds tested. Absolute configuration of 4,4',6,6'-tetranitrobiphenyl-2,2'-dicarboxylic acid (II) has been derived from its CD spectrum and some speculations on configuration of bipyridine diacid IV are presented.
Preparation of Phosphonomethyl Ethers Derived from 2-Phenylethanol and Its Amino Derivatives
Authors: Krečmerová Marcela , Holý Antonín
Published: July 2002

A series of compounds derived from the acyclic nucleoside antiviral 9-(2-phosphonomethoxyethyl)adenine (PMEA), in which the adenine ring is replaced by phenyl, 4-aminophenyl, 3-aminophenyl or 3,5-diaminophenyl group, has been prepared starting from the corresponding phenethyl alcohols. 2-(3-Aminophenyl)ethanol was prepared from 3-nitrobenzoyl chloride using the Arndt-Eistert reaction. The primarily formed diazoketone Ia was converted into ethyl 3-nitrophenylacetate (IIa) which on catalytic hydrogenation afforded ethyl 3-aminophenylacetate (IIIa). Compound IIIa was reduced with lithium aluminium hydride to give 2-(3-aminophenyl)ethanol (IVa). 2-(3,5-Diaminophenyl)ethanol (IVb) was prepared analogously from 3,5-dinitrobenzoyl chloride. After protection of the amino group with dimethylaminomethylene group, the alcohol IVa was converted to diisopropyl 2-(3-aminophenyl)ethoxymethylphosphonate (XII) by reaction with sodium hydride and diisopropyl p-toluenesulfonyloxymethanephosphonate, followed by deprotection of the amino group by treatment with ammonia. Reaction of diisopropyl ester XII with bromotrimethylsilane gave free 2-(3-aminophenyl)ethoxymethylphosphonic acid (XVII). The same procedure, applied to the corresponding aminophenethyl alcohols, afforded: 2-(4-aminophenyl)ethoxymethylphosphonic acid (XVI) and 2-(3,5-diamino phenyl)ethoxymethylphosphonic acid (XVIII). The synthesized compounds were tested in vitro on cell cultures for the cytostatic and antiviral activity (HSV-1, HSV-2, VSV, VZV, CMV). No antiviral activity has been found for any of the compounds.
Electron Donating, Acid-Base and Catalytic Properties of Perovskite-Type Mixed Oxides of Rare Earths
Authors: Sugunan S. , Meera V.
Published: July 2002

The electron donor properties of perovskite-type mixed oxides (LaFeO3, PrFeO3, SmFeO3, LaCoO3, PrCoO3, SmCoO3, LaNiO3, PrNiO3 and SmNiO3) were studied based on the adsorption of electron acceptors exhibiting different electron affinity viz. 7,7,8,8-tetracyanoquinodimethane, 2,3,5,6-tetrachloro-1,4-benzoquinone, p-dinitrobenzene, and m-dinitrobenzene. The surface acidity/basicity of the oxides was determined using a set of Hammett indicators. The data were correlated with the catalytic activity of the oxides for the reduction of cyclohexanone with 2-propanol.
Pressure Drop in the Flow of Viscoelastic Fluids Through Fixed Beds of Particles
Authors: Cakl Jiří , Machač Ivan
Published: July 2002

The results of experimental investigation of elastic effects in the creeping flow of viscoelastic fluids through fixed beds of spherical and nonspherical particles are presented. A simple form of the corrective Deborah number function has been suggested enabling relations valid for the fixed bed flow of purely viscous fluids to be used for the estimation of pressure drop in the flow of viscoelastic fluids.
Optically Active Furanoids Containing Cytosine-, Adenine- and Nicotinamide-Like Moieties
Authors: Werfeli Ali , Voltrová Svatava , Prutianov Viktor , Kuthan Josef
Published: July 2002

3-Hydroxymethyl-5-(2,3-O-isopropylidene-β-D-erythro-furanosyl)-2-methylfuran (2) prepared from 3-ethoxycarbonyl derivative 1 was converted to 3-chloromethyl-5-(2,3-O-isopropylidene-β-D-erythro-furanosyl)-2-methylfuran (3). Compound 3 reacted with cytosine, adenine, 6-chloropurine, 6-mercaptopurine, and nicotinamide to corresponding optically active heterocyclic derivatives 5-10 and 14. The 6-chloro derivative 9 was converted to 6-alkoxy derivatives 11 and 12 by the reaction with methanol or ethanol, respectively, in the presence of diazabicyclooctane. Dithionite reduction of quaternary chloride 14 gave 1,4-dihydropyridine derivative 15 capable to transform ethyl phenylglyoxylate to optically active ethyl mandelate.
The Dimeric Structure of Bis(1,3-Dimethylcyclopentadienyl)titanium(III) Chloride
Authors: Mach Karel , Varga Vojtech , Schmid Günter , Hiller Jörg , Thewalt Ulf
Published: July 2002

The X-ray crystal structure analysis of bis(1,3-dimethylcyclopentadienyl)titanium(III) chloride revealed that it is a centrosymmetric chlorine-bridged dimer [(η5-C5H3Me2)2Ti(μ-Cl)]2 (1) with the Ti-Ti distance of 3.9155(8) Å. Its skeleton is virtually identical with those of the [(η5-C5H5)2Ti(μ-Cl)]2 and [(η5-C5H4Me)2Ti(μ-Cl)]2 dimers. The solution EPR study proved that 1 remains a dimer in toluene whereas it dissociates in 2-methyltetrahydrofuran (MTHF) to give (η5-C5H3Me2)2TiCl . MTHF. The EPR spectra of frozen toluene solutions proved that 1 forms the triplet state whose g-tensor and zero-field splitting D are virtually the same as those of [(η5-C5H5)2Ti(μ-Cl)]2.
Crystal Structure, Thermoanalytical Properties and Infrared Spectra of Double Magnesium Selenates
Authors: Mička Zdeněk , Prokopová Lucie , Císařová Ivana , Havlíček David
Published: July 2002

Magnesium selenates double salts K2Mg(SeO4)2.6H2O, Rb2Mg(SeO4)2.6H2O, Cs2Mg(SeO4)2.6H2O, and (NH4)2Mg(SeO4)2.6H2O have been studied by means of X-ray diffraction methods, thermoanalytical methods, and infrared spectroscopy. The basic building units of these compounds are slightly deformed tetrahedra of selenate anions and octahedra of hexaaquamagnesium(II) cations interconnected by a system of hydrogen bonds. The investigation of IR spectra has been used in the discussion of X-ray diffraction results in the field of description of the hydrogen bond system and deformation of the basic polyhedra of selenate anion and hexaaquamagnesium cation. The thermoanalytical studies are used in evaluating the effects of hydrogen bonds and polarization influence of M+ cations on thermal stability of the compounds studied.
trans-Hydrindanes by Reduction: Synthesis of Dihydro-B-nortestosterone
Authors: Kasal Alexander , Chodounská Hana , Szczepek Wojciech J.
Published: July 2002

Reduction with diimide was employed in the synthesis of potential antiandrogens - 17β-hydroxy-B-nor-5α-androstan-3-one (26) and its 17α-methyl derivative (25). Other methods of reduction (hydroboration, catalytic hydrogenation) were less effective.
Electron Spin Resonance Super-Hyperfine Splitting Study of Polycrystalline Niobocene and Vanadocene Dichlorides
Authors: Holubová Jana , Černošek Zdeněk , Pavlík Ivan
Published: July 2002

The electron spin resonance (ESR) spectra of niobocene and vanadocene dichlorides were studied on the title compounds prepared as magnetically diluted species in polycrystalline form. The resolved super-hyperfine splitting of anisotropic ESR spectra of both studied compounds was firstly observed. Computer simulation confirmed that this super-hyperfine splitting is due to interaction of unpaired electron with nuclear spin of two chlorine ligands. Average value of super-hyperfine coupling constant is 13.3 MHz for niobocene dichloride. For vanadocene dichloride, it is estimated to be in the range of 6-10 MHz. It corresponds approximately to 10% delocalization of metal unpaired electron spin density onto chlorine ligands in case of niobocene dichloride and to 4-7% delocalization in case of vanadocene dichloride.
Synthesis, Conformational Analysis and Transannular Reactions of 5,9-Propanobenzo[7]annulene Derivatives
Authors: Camps Pelayo , Görbig Diana , Muñoz-Torrero Victoria , Pérez Francesc
Published: July 2002

(5α,9α,11β)-11-Hydroxy-6,7,8,9-tetrahydro-5H-5,9-propanobenzo[7]annulen-7-one ethylene ketal (6a) and its 11α-methyl derivative (6b) were prepared from monoketal 3. These compounds underwent acid-catalyzed transannular reactions leading to 6,7,8,9-tetrahydro-5H-5,9-propanobenzo[7]annulene derivatives 5a, 8a and 5b, 8b, respectively, depending on the reaction conditions. The compounds 6a and 6b were dehydrated to 6,7,8,9-tetrahydro-5H-5,9-prop[1]enobenzo[7]annulen-7-one (9a) and its 11-methyl derivative (9b), respectively. The conformational analysis of the 5,9-propanobenzo[7]annulene derivatives by molecular mechanics calculations (MM3 program) and the 1H NMR data show that hydroxyketal 6a and the related compound (5α,7β,9α)-6,7,8,9-tetrahydro-5H-5,9-propanobenzo[7]annulen-7-ol (4) exist mainly in the boat-chair conformation with the boat cycloheptenol ring, while for hydroxyketal 6b the chair-boat conformation (chair cycloheptenol ring) seems to be the preferred one.
Synthesis of (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(Carboxymethyl)]oxime, New Hapten for Dihydrotestosterone (17β-hydroxy-5α-androstan-3-one)
Authors: Černý Ivan , Slavíková Tereza , Pouzar Vladimír
Published: July 2002

Addition of 4-methoxybenzyl alcohol to 3β-hydroxy-5α-androst-15-en-17-one gave the mixture of isomeric 15-(4-methoxyphenyl)methoxy derivatives from which, after acetylation and chromatography, the major 15β isomer was separated. Borohydride reduction gave 17β-hydroxy derivative which was protected as methoxymethyl ether. Oxidative cleavage of protecting group at position 15 and the subsequent Jones oxidation afforded corresponding 15-ketone. Its oximation with O-(carboxymethyl)hydroxylamine, deacetylation and methylation with diazomethane gave protected O-(carboxymethyl)oxime derivative with free hydroxy group at position 3. Its oxidation afforded dihydrotestosterone derivative and successive deprotection of position 17 and of carboxy group led to final (15E)-17β-hydroxy-5α-androstane-3,15-dione 15-[O-(carboxymethyl)]oxime. The title compound was designed as dihydrotestosterone hapten for heterologous radioimmunoassays.
A Fructofuranan from the Roots of Rudbeckia fulgida, var. sullivantii (BOYNTON et BEADLE)
Authors: Kardošová Alžbeta , Matulová Mária
Published: July 2002

From the roots of Rudbeckia fulgida, var. sullivantii (BOYNTON et BEADLE), a homogeneous polysaccharide has been isolated by water extraction and subsequent ion-exchange chromatography and gel filtration of the crude mixture of polysaccharides. Its molar composition determined by NMR and HPLC analyses was found to be D-fructose and D-glucose in the ratio 26 : 1. The results of methylation analysis and 1H and 13C NMR spectral measurements showed that the polysaccharide is a (2 → 1)-β-D-fructofuranan of the inulin type.
A Facile Synthesis of the Enantiopure, Nitrogen-Substituted 2,2'-Diamino-1,1'-binaphthyls as Potential Ligands for Catalytic Asymmetric Reactions
Authors: Vyskočil Štěpán , Smrčina Martin , Kočovský Pavel
Published: July 2002

Reductive alkylation of (R)-(+)-2,2'-diamino-1,1'-binaphthyl (1) with various ketones has been accomplished by means of NaBH4/H2SO4 in THF at room temperature. Bisalkylation predominated with the sterically less demanding acetone (1→3a; 82%), whereas the bulky 2-adamantanone afforded mainly the monoalkylated product 4c (71%). Both mono- and bisalkylated diamines (R)-3 and (R)-4 were reductively permethylated on reaction with CH2O, NaBH4, and H2SO4. The Pd(0)-catalyzed phenylation of (R)-(+)-1 with PhBr afforded the N,N'-diphenyl derivative (R)-7 (70%).
Novel Amphiphilic Cyclodextrins: Per[6-deoxy-6-(4,5-dicarboxy-1,2,3-triazol-1-yl)-2,3-di-O-methyl] Derivatives
Authors: Kraus Tomáš , Buděšínský Miloš , Závada Jiří
Published: July 2002

Per[6-deoxy-6-(4,5-dicarboxy-1,2,3-triazol-1-yl)-2,3-di-O-methyl] substituted α- and β-cyclodextrins 6a and 6b were prepared by 1,3-dipolar cycloaddition reaction of the corresponding per(6-azido-6-deoxy-2,3-di-O-methyl)cyclodextrins 4a and 4b with dimethyl acetylenedicarboxylate.
Extraction of Cesium with Bis[undecahydro-7,8-dicarbaundecaborato(2-)]cobaltate(1-) in the Presence of 18-Crown-6
Authors: Vaňura Petr , Makrlík Emanuel
Published: July 2002

Extraction of cesium with a nitrobenzene solution of bis[undecahydro-7,8-dicarbaundecaborato(2-)]cobaltate(1-) in the presence of 18-crown-6 (18C6, L) has been investigated. The equilibrium data and typical dependences of the Cs distribution ratios on the analytical concentration of 18C6 in the system under study can be explained assuming that the complexes HL+, CsL+ and CsL2+ are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene saturated with water have been determined.
On-Line Simultaneous Sorption Preconcentration and Determination of Chromium(III) and Chromium(VI) with AAS Detection
Authors: Rychlovský Petr , Krenželok Milan , Volhejnová Radka
Published: July 2002

Speciation and simultaneous preconcentration of Cr(III) and Cr(VI) is based on the sorption of the reaction product of Cr(III) with Chromazurol S in weakly acidic solution and the sorption of the reaction product of Cr(VI) with sodium diethylcarbamate in strongly acidic solution. Reversed C18 phase was used for sorption of both the products. Both the complexes were eluted from columns directly into an AAS nebulizer using methanol. All the processes were automated. This method can be used for initial concentrations of Cr(III) and Cr(VI) below 1 ppm. The detection limits were 0.2 μg l-1 for Cr(III) and 2.4 μg l-1 for Cr(VI). This method was tested for analysis of practical samples (drinking and surface waters and soil extracts).
Phase Stability of Hydrogen-Bonded Polymer Mixtures. II. Mixtures of Intercomplexing Polymers
Authors: Pouchlý Julius , Živný Antonín , Sikora Antonín
Published: July 2002

Equations for the second derivative of the Gibbs energy of mixing with respect to composition were derived on the basis of the Barker-Guggenheim theory of quasichemical equilibrium for mixtures of two polymers containing polar groups and a nonpolar rest. Using equations derived, conditions for the phase separation in mixtures of two strongly intercomplexing polymer components were evaluated. The phase instability appears when the components differ in their polar group contents (strictly speaking, in their surface fractions in respective macromolecules), or due to an unfavorable interaction between nonpolar groups of the components. The effect is conditioned by small affinity of polar to nonpolar groups and may be influenced by the difference in this affinity between both components; nevertheless, the latter factors are not sufficient for a phase instability to occur.
Cyclization Dichotomy of D-xylo-Hex-5-ulosonamides and Synthesis of Piperidine Analogs of Aldohexoses and Aldohexono-1,5-lactones
Authors: Kováříková Radka , Ledvina Miroslav , Šaman David
Published: July 2002

The preparation of 2,3,4,6-tetra-O-benzyl-5-D-xylo-hex-5-ulosonamides 3a and 3b and their cyclization to 5-amino-2,3,4,6-tetra-O-benzyl-5-deoxy-D-glucono-1,5-lactam (4) and 5-amino- 2,3,4,6-tetra-O-benzyl-5-deoxy-D-talono-1,5-lactam (5) or to 2,3,4,6-tetra-O-benzyl-1,5-dideoxy-1,5-imino-D-glucitol (9), and also their direct transformation into 2,3,4,6-tetra-O-benzyl- D-talono-1,5-lactone (6), are described and discussed. The atypical boat conformation of D-talonolactam 5 and D-talonolactone 6 was found.
Biological Function and Chemistry of Endothelin. A Review
Authors: Hlaváček Jan , Marcová Renáta
Published: July 2002

The first part of this review deals with the biosynthesis and a biological function of strongly vasoactive peptides named endothelins (ETs) including vasoactive intestinal contractor. Where it was useful, snake venoms sarafotoxins which are structural endothelin derivatives, were also mentioned. In the second part, an attention is paid to structural basis of the ETs biological activity, with respect to alterations of amino acid residues in the parent peptides modifying the conformation and consequently the physico-chemical and biological properties in corresponding ETs analogs. Special attention is focussed on the area of ETs receptors and their interaction with peptide and non peptide agonists and antagonists, important in designing selective inhibitors of ETs receptors potentially applicable as drugs in a medicine. A review with 182 references.
Neurodevelopmental outcome in meningococcal disease: a case–control study
Authors: Fellick J M , Sills J A , Marzouk O , Hart C A , Cooke R W I , Thomson A P J
Published: July 2002

AIMS

To determine long term neurodevelopmental outcome following the spectrum of meningococcal infection.

METHODS

Between 1988 and 1990, 152 cases of meningococcal disease were recruited; 139 survived. Between 1998 and 1999, 115 survivors (83%) were evaluated, together with 115 sex and age matched controls. Standard measures of neurological function, coordination, cognition, behaviour, and hearing were used to assess neurodevelopmental status.

RESULTS

One case has spastic quadriplegia. Gross neurological examination was normal in all other cases and all controls. Five cases and no controls have significant hearing loss. Cases performed at a lower level than controls on measures of coordination, cognition, and behaviour. Four cases and no controls had major impairments. The adjusted odds ratios for moderate and minor impairments were 3.6 (95% CI 1.3 to 10.3) and 1.6 (95% CI 0.8 to 3.4) respectively.

CONCLUSION

The majority of survivors from this cohort do not have gross neurological deficits. However, when objective measures of motor function, cognitive ability, and behaviour were applied significant detriments were found in meningococcal survivors.
Clinical ethics committees and the formulation of health care policy
Authors: Doyal Len
Published: July 2002

For some time, clinical ethics committees (CECs) have been a prominent feature of hospitals in North America. Such committees are less common in the United Kingdom and Europe. Focusing on the UK, this paper evaluates why CECs have taken so long to evolve and assesses the roles that they should play in health care policy and clinical decision making. Substantive and procedural moral issues in medicine are differentiated, the former concerning ethicolegal principles and their paradigmatic application to clinical practice and the latter dealing with how such application should be negotiated in the face of disagreement and/or uncertainty. It will be argued that the role of CECs is both substantive and procedural. Provided that they do not overstep their appropriate moral and professional boundaries, CECs will be shown to have an important and positive function in improving hospital care within the UK and elsewhere.
Delivery of surgical care in a district general hospital without high dependency unit facilities
Authors: Coggins R P
Published: July 2002

Background

Many hospitals lack the facilities for high dependency care, and patients requiring this level of care are nursed on the surgical ward. The aim of this study was to assess the extent of this problem in a district general hospital, looking at the impact of providing high dependency unit (HDU) care at ward level.

Methods

A 28 bed surgical ward was studied for 39 consecutive days. Patients were assessed as being either appropriately placed (routine) or inappropriately placed (HDU). Nursing interventions and observations over each 24 hour period were recorded for the most dependent patient in each group.

Results

Data were collected for a total of 1092 bed days. Median bed occupancy was 22 patients/day (78%). Inappropriately placed HDU patients accounted for 55 bed days (5%, mean 1.4 patients/day). These patients required more nursing intervention than routine patients.

HDU patients received more observations during a 24 hour period than routine patients (mean 11.3 and 4.2 respectively, p<0.005). The number of observations recorded for a routine patient in a 24 hour period fell when a HDU patient was nursed concurrently on the ward (mean 5.1/24 hours, falling to 3.8 /24 hours in the presence of an HDU patient, p<0.02 ).

Conclusions

HDU patients require more intensive nursing care than routine surgical patients, and the nursing of HDU patients on the ward adversely affects the quantity of care available for less dependent patients. High dependency care should therefore be provided in dedicated units.

HDU is an essential facility for all surgical patients, including those who require intensive nursing, and the routine surgical patient whose nursing is compromised by the failure to provide comprehensive postoperative care.
Carotid sinus syndrome masquerading as treatment resistant epilepsy
Authors: Parry Steve W , Kenny Rose Anne
Published: July 2002

A 65 year old woman had a 12 year history of frequent, recurrent seizure-like episodes labelled as treatment resistant epilepsy after neurological evaluation and follow up and treatment with multiple antiepileptic medications. Carotid sinus massage provoked 5.6 seconds asystole with symptom reproduction, and she has remained symptom-free after permanent pacemaker implantation for her carotid sinus syndrome and withdrawal of antiepileptic medications.
Parasites in fine needle breast aspirates—assessment of host tissue response
Authors: Sahai K , Kapila K , Verma K
Published: July 2002

Parasites in the human breast are uncommon but not rare. Cysticercus and filariasis in fine needle breast aspirates have been documented and their cytomorphology is well characterised. However, the host tissue response to these parasites and the factors responsible for their initiation are not clear. Over a 21 year period, 28 cases of breast parasites (16 cases of cysticercus and 12 of filariasis), diagnosed by fine needle aspiration cytology, were reviewed to assess the host tissue response.
Spiral phyllotaxis of needle fascicles on branches and scales on cones in Pinus contorta var. latifolia: Are they influenced by wood-grain spiral?
Authors: Fredeen Arthur L , Horning Jeanne A , Madill Robert W
Published: July 2002

Neither the relationship between the chirality of spiral phyllotaxis and spiral wood grain nor the cause or ontogeny of such a relationship has been examined previously. To this end, chirality of the spiral in phyllotaxis of needle fascicles and cone scales were contrasted with wood-grain spiral in seedlings, young, and mature trees of Rocky Mountain lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) in central British Columbia. To assess chirality of phyllotaxis, the relationship between numbers of contact parastichies and chirality of phyllotaxis in scales on cones and needle fascicles on branchlets was determined. Three or 8 clockwise acropetal contact parastichies were indicative of a clockwise generative spiral, while totals of 2, 5, or 13 clockwise acropetal parastichies were indicative of a counter-clockwise generative spiral. Lodgepole pine trees were nearly always chimeric, i.e., having clockwise and counter-clockwise phyllotaxis on the same individual, but there was a high overall correspondence between the chirality of phyllotaxis in cone scales and subtending needle fascicles. Seedlings (<1.5 years old) had no measurable wood-grain angle and clockwise and counter-clockwise phyllotaxis occurred in equal proportions. However, young trees (1315 years since planting) had a pronounced clockwise bias to their wood-grain spiral in contrast with a counter-clockwise bias in phyllotaxis. In contrast, mature trees ([Formula: see text]100 years old) had the reverse trend and exhibited a counter-clockwise bias in wood-grain spiral but a clockwise bias in phyllotaxis. A model is proposed to explain how chirality of spiral wood grain could generate an inverse bias in the chirality of phyllotaxis in lodgepole pine.Key words: lodgepole pine, Pinus contorta var. latifolia, phyllotaxis, generative spiral, Fibonacci numbers, spiral wood grain.
The effect of visual isolation on territory size and population density of juvenile rainbow trout (Oncorhynchus mykiss)
Authors: Imre I , Grant J WA , Keeley E R
Published: July 2002

Visibility is thought to affect the territory size of visually oriented animals but there have been few experimental tests of the hypothesis. We re-examined the relationship between visibility and territory size in juvenile salmonids to test the hypothesis that increasing habitat heterogeneity results in a reduction in territory size and consequently in higher population densities. Equal densities of young-of-the-year rainbow trout (Oncorhynchus mykiss) were stocked in two experimental treatments with low visibility and a control treatment with high visibility. Visibility was decreased by placing large stones or plywood dividers onto the substrate of experimental stream channels. As predicted, the size of individual territories decreased with decreasing visibility of the habitat. However, the treatments did not differ significantly in population density or growth rate of the fish. While this study confirms the inverse relationship between habitat visibility and territory size, the decrease in territory size did not produce an increase in population density of juvenile salmonids.
Methoxychlor stimulates the mouse lactoferrin gene promoter through a GC-rich element
Authors: Zhang Zhiping , Teng Christina T
Published: July 2002

The lactoferrin gene in the mouse uterus is a target gene for natural estrogens and xenoestrogens. One of the xenoestrogens is methyoxychlor, an insecticide that displays both estrogenic and antiandrogenic activities. Recently, methyoxychlor was found to stimulate lactoferrin gene expression in the uterus of an estrogen receptor null mouse. The present study is designed to uncover the methoxychlor response region in the mouse lactoferrin gene promoter. A series of different lengths of the mouse lactoferrin gene 5' flanking region were linked to a chloramphenicol acetyltransferase (CAT) reporter construct and transfected into human endometrial carcinoma HEC-1B cells, an estrogen receptor null cell line, in order to examine the methoxychlor response. The transfected cells were treated with methoxychlor or the metabolite of methoxychlor, HPTE, and the CAT reporter activities were measured. Constructs that contain a mouse lactoferrin 5' region longer than 100 bp were activated more than twofold by both methoxychlor and HPTE. The activation of the CAT reporter by the chemicals was dose dependent and reached saturation. Additional deletion mutants within the 100-bp region were tested, and a GC-rich sequence (GC-II) that we have previously characterized as an epidermal growth factor (EGF) response element was identified to be the region for the methoxychlor response. GC-II binds Sp1, Sp3, and IKLF transcription factors, collaborates with the AP1/CREB binding element, and confers the EGF response. Whether the effect of methoxychlor requires the AP1/CREB binding element has yet to be established; however, the present finding provides an alternative signaling pathway for the xenoestrogens.Key words: xenoestrogen, methoxychlor, environmental, lactoferrin gene, promoter.
ORACLES IN $\Sigma^p_2$ ARE SUFFFICIENT FOR EXACT LEARNING
Authors: Köbler Johannes , Lindner Wolfgang
Published: July 2002

We study the learnability of representation classes in Angluin's exact learning model. In particular, we consider the following three query types: equivalence queries, equivalence and membership queries, and membership queries only. We show in all three cases that polynomial query complexity implies already polynomial-time learnability, provided that the learner additionally has access to an oracle in [Formula: see text]. It follows that boolean circuits are polynomial-time learnable with equivalence queries and the help of an oracle in [Formula: see text].a
EVALUATION OF THREE IMPLICIT STRUCTURES TO IMPLEMENT NONDETERMINISTIC AUTOMATA FROM REGULAR EXPRESSIONS
Authors: CHAMPARNAUD JEAN-MARC
Published: July 2002

The aim of this paper is to compare three efficient representations of the position automaton of a regular expression: the Thompson ∊-automaton, the [Formula: see text]-structure and the ℱ-structure, an optimization of the [Formula: see text]-structure. These representations are linear w.r.t. the size s of the expression, since their construction is in O(s) space and time, as well as the computation of the set δ(X,a) of the targets of the transitions by a of any subset X of states. The comparison is based on the evaluation of the number of edges of the underlying graphs respectively created by the construction step or visited by the computation of a set δ(X,a).
BEHAVIOR IN LARGE DIMENSIONS OF THE POTTS AND HEISENBERG MODELS
Authors: KESTEN H. , SCHONMANN R. H.
Published: July 2002

We extend to the Potts and Heisenberg models some of the results proven in [6] for the Ising model. For both these models we prove that if the interaction is properly normalized, then as the space dimensionality goes to ∞, the spontaneous magnetization converges to the value given by the corresponding Curie-Weiss model (except possibly at the Curie-Weiss transition point, in the case of the Potts model.) For the Potts model we prove also that the ordered phases approach product measures. The proofs are based on the convergence of the free energy to the Curie-Weiss value and on infrared bounds. A consequence of our result for the q-state Potts model is an asymptotic upper bound for the transition temperature, which for q > 2 is better than the one obtained by the conventional use of infrared bounds, or comparison inequalities between different Potts models.
INDEX THEORY OF PERTURBED DOLBEAULT OPERATORS: SMOOTH POLAR DIVISORS
Authors: FOX JEFFREY , HASKELL PETER
Published: July 2002

This paper generalizes the index-theoretic content of the physical models studied in [3, 7]. The paper calculates the homology Chern character, and thus the index formula, for a broad class of perturbed Dolbeault operators on complete noncompact complex manifolds. The manifolds studied are complements of smooth polar divisors of meromorphic sections of vector bundles over closed complex manifolds. These sections define complexes of Koszul type that are used to construct the perturbations of the Dolbeault operators.
MEASURING PRODUCTIVE CAPACITY REALIZATION OF BANGLADESH FOOD MANUFACTURING: A RANDOM COEFFICIENT FRONTIER APPROACH
Authors: SALIM RUHUL AMIN
Published: July 2002

The aim of this paper is to empirically estimate the firm level productive capacity realization (PCR) by using the stochastic coefficient frontier production function. Empirical estimations have been done using firm level data from Bangladesh food manufacturing covering the inter-temporal periods 1988, 1992 and 1996. The results suggest that there are considerable levels of unrealized production capacity in the food processing sector and very little improvement occurred in realization of productive capacity after the implementation of economic reforms. So, there is enough room for increasing output by realizing substantial unrealized capacity.
A RECURSION TECHNIQUE FOR DERIVING RENORMALIZED PERTURBATION EXPANSIONS FOR ONE-DIMENSIONAL ANHARMONIC OSCILLATOR
Authors: DOBROVOLSKA I. V. , TUTIK R. S.
Published: July 2002

A new recursion procedure for deriving renormalized perturbation expansions for the one-dimensional anharmonic oscillator is offered. Based upon the ℏ-expansions and suitable quantization conditions, the recursion formulae obtained have the same simple form both for ground and excited states and can be easily applied to any renormalization scheme. As an example, the renormalized expansions for the sextic anharmonic oscillator are considered.
A MEAN FIELD APPROACH TO THE COLORED HUBBARD MODEL
Authors: BAIER TOBIAS , BICK EIKE
Published: July 2002

By subdividing a 2d square lattice into plaquettes containing 4 lattice sites each, the Hubbard Hamiltonian is reformulated in terms of different "colored" fermion species. This makes it possible to describe e.g. antiferromagnetic order or d-wave superconductivity in terms of expectation values of composite scalar fields. A suitable mean field approximation indeed reproduces qualitatively the measured phase diagram and shows a competition between phases with antiferromagnetic ordering and dx2-y2-superconductivity at low temperatures.