bluuebunny/crossref_metadata_2025 huggingface dataset:
Distribution of killer‐cell immunoglobulin‐like receptor (KIR) in Comoros and Southeast France
Authors: Frassati C. , Touinssi M. , Picard C. , Segura M. , Galicher V. , Papa K. , Gagne K. , Vivier E. , Degioanni A. , Böetsch G. , Mercier P. , Vély F. , De Micco P. , Reviron D. , Chiaroni J.
Published: May 2006

Killer‐cell immunoglobulin‐like receptors (KIRs) expressed by natural killer cells are cell surface molecules able to recognize groups of HLA class I alleles. The number and distribution of KIR genes vary among individuals and populations. The aim of this study is to analyse the KIR gene content in a Comorian population in order to investigate genetic relationships with other populations and to reconstruct past migration events. The Comorian population consisted of 54 unrelated immigrants living in France and a control population consisted of 38 individuals from Southeast France. We investigated the presence or absence of 15 KIR genes, two pseudogenes expressed and non‐expressed forms of KIR2DL5 and the two major subtype full‐length and deleted forms of KIR2DS4. All individuals were typed positive for the framework genes, i.e. KIR2DL4, KIR3DL2 and KIR3DL3, and the two pseudogenes KIR3DP1 and KIR2DP1. The frequencies of full‐length KIR2DS4 (*00101/00102/002) were lower in the French population (F = 29%) than in the Comorian population (F = 72%) (Pc < 0.05). No significant differences were found for other KIR genes. A total of 11 genotypes were identified in the Southeast French population and 22 genotypes in the Comorian population. The most common genotype (2DL1, 2DL3, 2DL4, 3DL1, 3DL2, 3DL3 and 2DS4) accounted for 41% in the Comorian population and 34% in the Southeast French population. Principal component analysis using KIR gene data from 20 populations was performed to determine genetic differences and relations between populations. The Comorian population exhibited closest kinship with Africans and Asians. As KIR gene content is heterogeneous among ethnic groups, it can probably be used to assess the genetic relationships among populations from different geographic areas.
Outbreak Investigations: Community Participation and Role of Community and Public Health Nurses
Authors: Sistrom Maria Gilson , Hale Patty J.
Published: May 2006

ABSTRACT
Community and public health nurses (C/PHNs) may play a vital role in the investigation of disease outbreaks. C/PHNs possess skills in conducting interviews on sensitive subjects and in collaborating with communities. C/PHNs maintain key links to community providers, symptomatic clients, their families and associates, as well as community institutions where outbreaks occur. This combination of skills makes C/PHNs ideally suited to perform outbreak investigations. There are, however, pressing questions about whether C/PHNs are adequately prepared to contribute to investigation outcomes, to foster participation of affected communities, and to fully apply nursing skills to outbreak investigations to stop the spread of disease. Using one case study, the authors explore investigation outcomes, community participation issues, educational preparation, and public health funding and workforce policies required to achieve these ends successfully. One model of community participation in the steps of outbreak investigation and several Quad Council domains and competencies are proposed for use in practice. Questions regarding the use of emergency preparedness funding and employment of C/PHNs in epidemiology roles are raised.
Health Care for Older Persons in Switzerland: A Country Profile
Authors: Schoenenberger Andreas W. , Stuck Andreas E.
Published: May 2006

Switzerland has the second‐most‐expensive healthcare system worldwide, with 11.5% of gross domestic product spent on health care in 2003. Switzerland has a healthcare system with universal insurance coverage and a social insurance system, ensuring an adequate financial situation for 96% of the 1.1 million older inhabitants.

Key concerns related to the care of older persons are topics such as increasing healthcare costs, growing public awareness of patient autonomy, and challenges related to assisted suicide. In 2004, the Swiss Academy of Medical Sciences issued guidelines for the care of disabled older persons.

Since 2000, geriatrics has been a board‐certified discipline with a 3‐year training program in addition to 5 years of training in internal or family medicine. There are approximately 125 certified geriatricians in Switzerland, working primarily in geriatric centers in urban areas. Switzerland has an excellent research environment, ranking second of all countries worldwide in life sciences research—but only 13th in aging research. This is in part due to a lack of specific training programs promoting research on aging and inadequate funding. In addition, there is a shortage of academic geriatricians in Switzerland, in part due to the fact that two of five Swiss universities had no academic geriatric departments in 2005. With more‐adequate financial resources for academic geriatrics, Switzerland would have the opportunity to contribute more to aging research internationally and to improved care for older patients.
Otomicroscopic findings and systemic interleukin‐6 levels in relation to etiologic agent during experimental acute otitis media
Authors: FOGLÉ‐ANSSON MARGARETHA , WHITE PETER , HERMANSSON ANN , MELHUS ÅSA
Published: May 2006

The aim of the present study was to explore whether it was possible to differentiate the clinical course and the otomicroscopic appearance of acute otitis media (AOM) caused by common otitis pathogens in an animal model. Systemic interleukin (IL)‐6 levels as early markers for bacterial AOM were also studied. Four groups of rats were inoculated with either Streptococcus pneumoniae, Streptococcus pyogenes, non‐typeable Haemophilus influenzae or Moraxella catarrhalis. The animals were monitored by otomicroscopy, photos of the tympanic membrane, cultures and IL‐6 detection in serum the following 4 days. The gram‐positive S. pneumoniae and S. pyogenes induced severe AOM with opaque effusion behind the tympanic membrane, pronounced dilation of the vessels and spontaneous perforations. The gram‐negative H. influenzae and M. catarrhalis induced a less severe infection with cloudy, sometimes foamy effusion, and no spontaneous perforations. With the otomicroscopic findings it was possible to distinguish between infections induced by gram‐positive bacteria and gram‐negative bacteria. Detection of interleukin‐6 in serum appeared to be of limited use for all infections except the pneumococcal AOM, but this needs to be further investigated.
Detection of Chlamydophila pneumoniae IgG in paired serum samples: comparison of serological techniques in pneumonia cases
Authors: DE ORY FERNANDO , GUISASOLA MARÍA EULALIA , EIROS JOSÉ MARÍA
Published: May 2006

Serological diagnosis of Chamydophila pneumoniae is usually undertaken by complement fixation test (CFT) or by microimmunofluorescence (MIF). A number of commercial methods for detecting C. pneumoniae‐specific IgG have been developed. The aim of this study was to compare the performance characteristics of six methods for the diagnosis of pneumonia due to C. pneumoniae, including CFT (in house), MIF (Vircell, Spain), and four ELISAs (Medac, Germany; Savyon, Israel; Serion, Germany; and DRG, Germany). ELISA‐Medac, ELISA‐Savyon, ELISA‐DRG and MIF use C. pneumoniae antigens while ELISA‐Serion and CFT use Chlamydophila genus‐specific antigen. Acute and convalescent samples from 85 pneumonia patients were studied. Using CFT, cases were initially classified as due to Chlamydophila (43 cases); to other agents (23 cases) (influenza A and B, Mycoplasma pneumoniae, respiratory syncytial virus, adenovirus and Legionella pneumophila); or as negative (19 cases). Cases were considered positive if they showed seroconversion, a significant rise in titer or high titer; and were finally classified as positive if they gave a positive result in at least three assays. Sensitivity values ranged from 87% to 97.8%; and specificity from 84.6% to 97.4%. In conclusion, the assays compared appear to be useful tools for the diagnosis of pneumonia due to Chlamydophila.
Treatment of neutral glycosphingolipid lysosomal storage diseases via inhibition of the ABC drug transporter, MDR1
Authors: Mattocks Michael , Bagovich Maria , De Rosa Maria , Bond Steve , Binnington Beth , Rasaiah Vanessa I. , Medin Jeffrey , Lingwood Clifford
Published: May 2006

We have shown that the ABC transporter, multiple drug resistance protein 1 (MDR1, P‐glycoprotein) translocates glucosyl ceramide from the cytosolic to the luminal Golgi surface for neutral, but not acidic, glycosphingolipid (GSL) synthesis. Here we show that the MDR1 inhibitor, cyclosporin A (CsA) can deplete Gaucher lymphoid cell lines of accumulated glucosyl ceramide and Fabry cell lines of globotriaosyl ceramide (Gb3), by preventing de novo synthesis. In the Fabry mouse model, Gb3 is increased in the heart, liver, spleen, brain and kidney. The lack of renal glomerular Gb3 is retained, but the number of verotoxin 1 (VT1)‐staining renal tubules, and VT1 tubular targeting in vivo, is markedly increased in Fabry mice. Adult Fabry mice were treated with α‐galactosidase (enzyme‐replacement therapy, ERT) to eliminate serum Gb3 and lower Gb3 levels in some tissues. Serum Gb3 was monitored using a VT1 ELISA during a post‐ERT recovery phase ± biweekly intra peritoneal CsA. After 9 weeks, tissue Gb3 content and localization were determined using VT1/TLC overlay and histochemistry. Serum Gb3 recovered to lower levels after CsA treatment. Gb3 was undetected in wild‐type liver, and the levels of Gb3 (but not gangliosides) in Fabry mouse liver were significantly depleted by CsA treatment. VT1 liver histochemistry showed Gb3 accumulated in Kupffer cells, endothelial cell subsets within the central and portal vein and within the portal triad. Hepatic venule endothelial and Kupffer cell VT1 staining was considerably reduced by in vivo CsA treatment. We conclude that MDR1 inhibition warrants consideration as a novel adjunct treatment for neutral GSL storage diseases.
DEVELOPMENT OF DIVING BY HARBOR SEAL PUPS IN TWO REGIONS OF ALASKA: USE OF THE WATER COLUMN
Authors: Frost Kathryn J. , Simpkins Michael A. , Small Robert J. , Lowry Lloyd F.
Published: May 2006

Abstract

Satellite‐linked dive recorders were attached to 53 harbor seal pups in Prince William Sound (PWS) and at Tugidak Island, Alaska, during 1997–1999. We used generalized additive models and bootstrap techniques to describe pup diving behavior during their first year of life. Pups increased their ability to dive during the first 3–6 mo, as indicated by increases in proportion of time in the water (time wet) and maximum dive depth achieved by a pup each day (max‐depth) values. Time wet and/or max‐depth later decreased, suggesting a seasonal component to diving behavior. Monthly time wet varied from an overall minimum of 0.68 at tagging in July to a maximum of 0.89 in November. Pups spent half of their time wet swimming in water <25 m deep, the shallowest 30% of the available water column. They spent only 5% of their time swimming in the deepest 30% of the available water column, at depths >60–70 m. This strongly suggests they were not feeding on or near bottom during their first year. Average max‐depths and deepest actual dives were similar for PWS and Tugidak pups. PWS pups dove deeper sooner and spent less time wet than Tugidak pups during the first few months after tagging, probably as a result of regional bathymetric differences. Diving behavior and body condition suggest that food availability was not likely a major factor in the population decline in PWS during the period of this study.
On Predicting the Effects of Streamline Curvature on the Turbulent Prandtl Number
Authors: Younis Bassam A. , Berger Stanley A.
Published: May 2006

Streamline curvature in the plane of the mean flow is known to exert a proportionately greater effect on the turbulent mixing processes than might be expected from inspection of the conservation equations governing the evolution of the turbulence field. For the case of momentum transport, streamline curvature in the destabilizing sense increases the Reynolds stresses throughout all regions of the flow while the effects of stabilizing curvature are to reduce these parameters relative to their plane flow values. In the limit of strong stabilizing effects, the turbulence activity is suppressed altogether with the mean flow and turbulence parameters asymptoting to their laminar-flow limits. When heat transfer is present, the experimental findings appear to suggest that the rate of heat transfer by the turbulent motions is more sensitive to the effects of curvature than that of momentum transfer. This is equivalent to an increase in the value of the turbulent Prandtl number with increasing stabilizing curvature. The conventional gradient-transport model, with its built-in assumption of constant Prandtl number, cannot reproduce this result. The purpose of the work reported in this paper was to investigate whether the use of alternative, explicit, and nonlinear models for the turbulent scalar fluxes results in the prediction of a more realistic response of the turbulent Prandtl number to stabilizing curvature effects.
IMRT: Improvement in treatment planning efficiency using NTCP calculation independent of the dose‐volume‐histogram
Authors: Grigorov Grigor N. , Chow James C. L. , Grigorov Lenko , Jiang Runqing , Barnett Rob B.
Published: May 2006

The normal tissue complication probability (NTCP) is a predictor of radiobiological effect for organs at risk (OAR). The calculation of the NTCP is based on the dose‐volume‐histogram (DVH) which is generated by the treatment planning system after calculation of the 3D dose distribution. Including the NTCP in the objective function for intensity modulated radiation therapy (IMRT) plan optimization would make the planning more effective in reducing the postradiation effects. However, doing so would lengthen the total planning time. The purpose of this work is to establish a method for NTCP determination, independent of a DVH calculation, as a quality assurance check and also as a mean of improving the treatment planning efficiency. In the study, the CTs of ten randomly selected prostate patients were used. IMRT optimization was performed with a PINNACLE3 V 6.2b planning system, using planning target volume (PTV) with margins in the range of . The DVH control points of the PTV and OAR were adapted from the prescriptions of Radiation Therapy Oncology Group protocol P‐0126 for an escalated prescribed dose of . This paper presents a new model for the determination of the rectal NTCP . The method uses a special function, named GVN (from Gy, Volume, NTCP), which describes the if of the volume of intersection of the PTV and rectum is irradiated uniformly by a dose of . The function was “geometrically” normalized using a prostate‐prostate ratio (PPR) of the patients’ prostates. A correction of the for different prescribed doses, ranging from , was employed in our model. The argument of the normalized function is the , and parameters are the prescribed dose, prostate volume, PTV margin, and PPR. The of another group of patients were calculated by the new method and the resulting difference was in comparison to the NTCP calculated by the PINNACLE3 software where Kutcher's dose‐response model for NTCP calculation is adopted.
Region‐of‐interest reconstruction of motion‐contaminated data using a weighted backprojection filtration algorithm
Authors: King Martin , Pan Xiaochuan , Yu Lifeng , Giger Maryellen
Published: May 2006

The recently developed weighted backprojection filtration (WBPF) algorithm using data redundancy has capabilities that make this algorithm an attractive candidate for reconstructing images from motion‐contaminated projection data. First, the WBPF algorithm is capable of reconstructing region‐of‐interest (ROI) images from reduced‐scan fan‐beam data, which have less data than the short‐scan data required to reconstruct the entire field of view (FOV). Second, this algorithm can reconstruct ROI images from truncated data. Using phantom simulation studies, we demonstrate how these unique capabilities can be exploited to reduce the amount of motion‐contaminated data used for reconstruction. In particular, we use examples from cardiac imaging to illustrate how off‐center phantom positioning combined with phase‐interval ROI reconstruction can result in the suppression of motion artifacts. In terms of temporal resolution, reduced‐scan reconstruction with 45% of a full‐scan dataset can be used to improve the temporal resolution of a short‐scan reconstruction by 25.8% if ungated data are used. For data gated at , reduced‐scan reconstruction with 45% of a full‐scan dataset can be used to improve the temporal resolution of a short‐scan reconstruction by 7.9%. As a result of our studies, we believe that the WBPF algorithm demonstrates the potential for reconstructing quality ROI images from motion‐contaminated fan‐beam data.
Fast voxel and polygon ray‐tracing algorithms in intensity modulated radiation therapy treatment planning
Authors: Fox Christopher , Romeijn H. Edwin , Dempsey James F.
Published: May 2006

We present work on combining three algorithms to improve ray‐tracing efficiency in radiation therapy dose computation. The three algorithms include: An improved point‐in‐polygon algorithm, incremental voxel ray tracing algorithm, and stereographic projection of beamlets for voxel truncation. The point‐in‐polygon and incremental voxel ray‐tracing algorithms have been used in computer graphics and nuclear medicine applications while the stereographic projection algorithm was developed by our group. These algorithms demonstrate significant improvements over the current standard algorithms in peer reviewed literature, i.e., the polygon and voxel ray‐tracing algorithms of Siddon for voxel classification (point‐in‐polygon testing) and dose computation, respectively, and radius testing for voxel truncation. The presented polygon ray‐tracing technique was tested on 10 intensity modulated radiation therapy (IMRT) treatment planning cases that required the classification of between 0.58 and 2.0 million voxels on a isotropic dose grid into 1–4 targets and 5–14 structures represented as extruded polygons (a.k.a. Siddon prisms). Incremental voxel ray tracing and voxel truncation employing virtual stereographic projection was tested on the same IMRT treatment planning cases where voxel dose was required for 230–2400 beamlets using a finite‐size pencil‐beam algorithm. Between a 100 and 360 fold cpu time improvement over Siddon's method was observed for the polygon ray‐tracing algorithm to perform classification of voxels for target and structure membership. Between a 2.6 and 3.1 fold reduction in cpu time over current algorithms was found for the implementation of incremental ray tracing. Additionally, voxel truncation via stereographic projection was observed to be 11–25 times faster than the radial‐testing beamlet extent approach and was further improved 1.7–2.0 fold through point‐classification using the method of translation over the cross product technique.
Isolation and Characterization of a New
Clostridium
sp. That Performs Effective Cellulosic Waste Digestion in a Thermophilic Methanogenic Bioreactor
Authors: Shiratori Hatsumi , Ikeno Hironori , Ayame Shohei , Kataoka Naoaki , Miya Akiko , Hosono Kuniaki , Beppu Teruhiko , Ueda Kenji
Published: May 2006

A methanogenic bioreactor that utilized wastepaper was developed and operated at 55°C. Microbial community structure analysis showed the presence of a group of clostridia that specifically occurred during the period of high fermentation efficiency. To isolate the effective cellulose digester, the sludge that exhibited high fermentation efficiency was inoculated into a synthetic medium that contained cellulose powder as the sole carbon source and was successively cultivated. A comprehensive 16S rRNA gene sequencing study revealed that the enriched culture contained various clostridia that had diverse phylogenetic positions. The microorganisms were further enriched by successive cultivation with filter paper as the substrate, as well as the bait carrier. A resultant isolate, strain EBR45 (=
Clostridium
sp. strain NBRC101661), was a new member of the order
Clostridiales
phylogenetically and physiologically related to
Clostridium thermocellum
and
Clostridium straminisolvens
. Specific PCR-based monitoring demonstrated that strain EBR45 specifically occurred during the high fermentation efficiency period in the original methanogenic sludge. Strain EBR45 effectively digested office paper in its pure cultivation system with a synthetic medium.
Development and Evaluation of a Rapid, Simple, and Sensitive Immunochromatographic Assay To Detect Thermostable Direct Hemolysin Produced by
Vibrio parahaemolyticus
in Enrichment Cultures of Stool Specimens
Authors: Kawatsu Kentaro , Ishibashi Masanori , Tsukamoto Teizo
Published: May 2006

Thermostable direct hemolysin (TDH) is considered to be a major virulence factor in
Vibrio parahaemolyticus
, and most cases of
V. parahaemolyticus
diarrhea in humans are caused by
tdh
gene-positive strains. In the present study, we developed an immunochromatographic assay to detect TDH (TDH-ICA) and evaluated the utility of TDH-ICA for the diagnosis of
V. parahaemolyticus
diarrhea. TDH-ICA allowed the detection of 0.2 ng/ml of TDH within 10 min. Fecal homogenates were spiked with various numbers of
tdh
-positive
V. parahaemolyticus
organisms, and their enrichment cultures were tested with TDH-ICA. The results of detection of TDH in the enrichment cultures by TDH-ICA were in accord with the results of recovery of the spiked
V. parahaemolyticus
organisms from the enrichment cultures by plating onto thiosulfate-citrate-bile salts-sucrose agar. When enrichment cultures of 217 stool specimens from patients with diarrhea were tested with TDH-ICA, the TDH-ICA results showed 100% sensitivity and specificity compared to the results of isolation of
V. parahaemolyticus
from the stool specimens by a conventional bacterial culture test. Since TDH-ICA was able to detect TDH in a fecal enrichment culture within 10 min, TDH-ICA testing of a fecal enrichment culture could be completed rapidly and easily within approximately 16 h, including incubation time for the fecal enrichment culture. These results indicate that TDH-ICA is a rapid, simple, and sensitive TDH detection method and that TDH-ICA testing of a fecal enrichment culture is useful as an adjunct to facilitate the early diagnosis of
V. parahaemolyticus
diarrhea.
Synthesis of caerulomycin
Authors: Ranganathan S. , Singh B. B. , Divekar P. V.
Published: May 2006

The synthesis of Caerulomycin starting from the known 4-methoxy-2,2′-bipyridyl-1-oxide, prepared from 2,2′-bipyridyl, is described.
Formation of diphenyl nitroxide in diphenylamine inhibited autoxidations
Authors: Adamic K. , Dunn M. , Ingold K. U.
Published: May 2006

The formation of diphenyl nitroxide in diphenylamine inhibited, α,α′-azo-bis-isobutyronitrile initiated, autoxidations at 65° has been studied by electron spin resonance. Diphenylamine is oxidized to a diphenylamino radical which is then converted to the nitroxide by an oxygen atom transfer from a peroxy radical. The initial rates of conversion of diphenylamine to diphenyl nitroxide and the maximum nitroxide concentrations attained are generally greater for oxidations with tertiary peroxy radicals than for oxidations with primary or secondary peroxy radicals. The lower efficiency of nitroxide formation by primary and secondary peroxy radicals is attributed to a cage disproportionation between alkoxy radical and nitroxide which leads to the formation of a carbonyl compound and diphenyl hydroxylamine. This reaction cannot occur with tertiary radicals. The rate of formation of diphenyl nitroxide is greater for tertiary peroxy radicals which give stable tertiary alkoxy radicals. Nitroxide formation is inhibited by secondary, but not by tertiary, hydroperoxides.
Dimethylboric anhydride: a convenient preparation and full characterization
Authors: Lanthier G. F. , Graham W. A. G.
Published: May 2006

Dimethylboric anhydride, (CH3)2BOB(CH3)2, has been prepared by limited hydrolysis of dimethylboron chloride and complete characterization has been carried out. The Lewis acid character of boron and the donor strength of oxygen have been studied using tensimetric and nuclear magnetic resonance techniques.Evidence for boron–oxygen π-bonding obtained from complex formation studies, using trimethylboron as a reference acid, is presented and discussed. The reduced acidity of the boron atoms, in comparison with trimethylboron, is discussed in terms of boron–oxygen π-bonding.
Effect of metal–oxygen bond on the sensitivity of atomic-absorption spectroscopic technique
Authors: Sastri Vedula S. , Chakrabarti Chuni L. , Willis Douglas E.
Published: May 2006

Studies on sensitivity in atomic absorption spectroscopy of nickel, tin, titanium, zirconium, hafnium, niobium, and tantalum, as metallocenes and as simple salts or oxy-salts, have shown that the metal–oxygen bonded species in solution (as in the case of simple salts or oxy-salts or complexes with ligands having oxygen atom as the donor) contributes to the total amount of metal oxide in flames, and hence, depopulates the ground electronic state of the atom in flames. In the case of the metals which form oxides of high dissociation energy, sensitivity is enhanced if the metals in solution are not bonded to oxygen as in metallocenes or fluoro complexes. The importance of the dissociation equilibrium and the reduction equilibrium in populating the ground electronic state of the atom has been assessed, and an irregular correlation has been established of enhancement in sensitivity with the metal–oxygen dissociation energy.
Total synthesis of (±)-aristolone
Authors: Piers Edward , Britton Ronald W. , Waal William de
Published: May 2006

A novel and efficient total synthesis of the racemic form of the sesquiterpene (−)-aristolone (1) is presented. The key step involves the cupric sulfate catalyzed intramolecular cyclization of the diazoketone 27, which produces a mixture of products, the major component of which is (±)-aristolone.
Cyclic organophosphorus compounds. III. Reactions of nitrosyl chloride with cyclic and open-chain hydrogen thiophosphites
Authors: Zwierzak Andrzej , Michalski Jan
Published: May 2006

2-Thiono-5,5-dimethyl-1,3,2-dioxaphosphorinan 1 treated with nitrosyl chloride yields a mixture of asymmetric 2 and symmetric 3 dithiopyrophosphates. Reinvestigation of the reaction of nitrosyl chloride with diethyl thiophosphite showed that, in addition to tetraethyl thiopyrophosphate, the corresponding dithiopyrophosphates are also formed. A mechanism is suggested for the reactions investigated, with nitrosyl chloride as an ambident nucleophile.
S-[(N-Terpenoid carboxamidinium)methyl] thiosulfates (Bunte salts) as potential antiradiation agents
Authors: Barton Jerry M. , Bauer Ludwig
Published: May 2006

The synthesis of a number of α-acetamidinium Bunte salts, substituted on one of the nitrogen atoms by a terpenoid moiety, is reported.
Nucleophilic displacement of vinylic halogen in fluorinated cycloalkenes. II. Reaction with triphenylphosphine
Authors: Ellzey Jr. S. E.
Published: May 2006

1,2-Dichloroperfluorocyclobutene and the corresponding cyclopentene react with triphenylphosphine under hydrolytic conditions in wet acetic acid to yield novel triphenyl(fluorocycloalkenyl)phosphonium betaines. Structural assignments are made on the basis of elemental analysis, 1H and 19F nuclear magnetic resonance spectra, infrared spectra, and degradation studies. Triphenylphosphine and 1,2-dichloroperfluorocyclohexene yield triphenylphosphine oxide and a product which appears to be 1-chloro-2-hydrooctafluorocyclohexene.
Proton magnetic resonance investigation of the system zinc perchlorate–methanol: evidence for the association of zinc and perchlorate ions
Authors: Al-Baldawi S. A. , Gough T. E.
Published: May 2006

The proton magnetic resonance spectrum of the system zinc perchlorate–methanol is reported for a range of sample concentrations and temperatures. The results are interpreted in terms of association between the zinc and perchlorate ions, and the various features of the spectrum discussed in terms of this interaction. From the temperature-dependence of line-widths, Ea = 14 ± 2 kcal mole−1 and log10A = 16 ± 3 are estimated for the molecular exchange of methanol from the solvation shell of zinc into the bulk solvent.
Stereochemistry of bimolecular nucleophilic opening of a dioxolenium ring fused to an anchored cyclohexane system
Authors: King J. F. , Allbutt A. D.
Published: May 2006

This paper describes the characterization of certain dioxolenium salts in which the heterocyclic ring is fused (via positions-4 and -5) to an anchored cyclohexane ring, and the steric course of their bimolecular cleavage with nucleophilic reagents. It was found that diaxial opening is normally favored strongly over diequatorial; this is accounted for in terms of differences in angle strain in the transition states. The presence of an axial (angular) methyl group gave a preference for diequatorial opening; on the other hand an analogous investigation of the diaxial: diequatorial opening ratio with epoxides showed the stereochemistry of the reaction to be virtually insensitive to an angular methyl group. These observations are interpreted in terms of the different non-bonded interactions arising from the different geometrical arrangements of epoxides and dioxolenium ions. The variation in the diaxial: diequatorial opening ratio is shown to be of significance in the interpretation of rates of diaxial → diequatorial rearrangement.
Further studies on the Stobbé condensation with 2-methyl cyclohexanone
Authors: El-Abbady A. M. , El-Ashry M. , Doss S. H.
Published: May 2006

2-Methyl cyclohexanone is condensed with dimethyl succinate in the presence of potassium tertiary butoxide giving a solid mixture of isomers of the corresponding alkylidene and alkenyl half-esters. On alkaline hydrolysis this gives β-carboxy-β-(2-methyl cyclohex-1-enyl)propionic acid. The keto-ester obtained by cyclization of the half-ester yielded the corresponding unsaturated ketone after acid hydrolysis and decarboxylation. Reduction of the keto-ester affords the corresponding α,β-unsaturated ester. Both the unsaturated ketone and ester are easily hydrogenated in the presence of platinum oxide to the corresponding saturated ketone and ester.
Acylation and alkylation of 1,3-dimethoxybenzene in polyphosphoric acid
Authors: Kasturi T. R. , Damodaran K. M.
Published: May 2006

Products of the reaction of 3-halo- and 3-ethoxypropionic acids with 1,3-dimethoxybenzene (4) in polyphosphoric acid have been shown to be 2′,4′-dimethoxy-3-(2,4-dimethoxyphenyl)-propiophenone (6) and 1,5-bis[3-(2,4-dimethoxyphenyl)-3-keto-propyl]-2,4-dimethoxybenzene (15) and these have been prepared by unambiguous syntheses. 2′,4′-Dimethoxy-3-ethoxypropiophenone (3a) and 2′,3,4′-trimethoxypropiophenone (3d) have been synthesized by the reaction of 3-chloro-2′,4′-dimethoxy- propiophenone (3c) with ethanol and methanol respectively.
Abstraction of hydrogen atoms from bicyclo[2.1.1]hexane by methyl radicals and chlorine atoms: photochlorination of 1-methylbicyclo[2.1.1]hexane
Authors: Srinivasan R. , Sonntag F. I.
Published: May 2006

Photolysis of acetone has been used as a source of methyl radicals to study the abstraction of hydrogen atoms from bicyclo[2.1.1]hexane by methyl radicals. The reaction was found to have an activation energy of 10.3 kcal/mole and a pre-exponential factor that is typical of other abstraction reactions. The absolute rate of abstraction of hydrogen atoms from bicyclo[2.1.1]hexane by chlorine atoms at room temperature was measured to be 8.1 × 1010 l mole−1 s−1. The photochlorination of 1-methylbicyclo-[2.1.1]hexane in solution gave both the 1-chloromethyl and 2- or 3-chloro-1-methylbicyclohexanes. The relative rates of attack at the methyl and the 2- or 3- position were determined to be 1:2.1. It is pointed out that the rate parameters for the abstraction of an H atom from bicyclo[2.1.1]hexane by a methyl radical are slower than for cyclopentane, as would be expected for a highly strained hydrocarbon, whereas the abstraction by chlorine is slightly faster than the rate for cyclopentane.
Etude de la décomposition des diazo-2 dicétones-1,3. I. Cas du diazo-2 diméthyl-5,5 cyclohexanedione-1,3
Authors: Veschambre Henri , Vocelle Daniel
Published: May 2006

not available
Approaches to the synthesis of triterpenoids. I. Methyl group migration to the 9β-position in steroids as a route to the cucurbitacins. A possible structural feature directing epoxide cleavage rearrangements
Authors: ApSimon J. W. , King R. R. , Rosenfeld J. J.
Published: May 2006

The BF3 catalyzed cleavage of some steroidal 9α, 11α-epoxides has been studied in an attempt to induce migration of the C-10 methyl group to C-9. In the case of 9α,11α-epoxyandrost-4-ene-3,17-dione, cleavage with BF3 gas in benzene led to two major products. One of these was the required 3,11α-dihydroxy-9β-methylestra-1,3,5(10)-triene-17-one, thus leading to a novel class of steroids and possibly opening a route to the synthesis of compounds of the cucurbitacin class. The other main product was shown to be 11α-hydroxy-9β-androst-4,8(14)-diene-3,17-dione. A possible structural feature directing the rearrangement pathway to these materials is proposed from the study of other epoxide rearrangements and some reported in the literature.
Chemistry of the aminochromes. Part XII. Some new aminochromes and their derivatives
Authors: Heacock R. A. , Hutzinger O.
Published: May 2006

The synthesis of a number of new aminochromes (and their monosemicarbazones) derived from catecholamines containing: (a) a primary amino group and (b) an alkoxy group in the β-position of the ethylamine side chain is reported. Improved procedures for the preparation of some previously described aminochromes of these types including 7-iodonorepinochrome and adrenochrome methyl and ethyl ethers are also given.
Photolysis of benzil in 2-propanol and in cumene
Authors: Bunbury David L. , Chuang Tze Tang
Published: May 2006

Benzil has been irradiated in 2-propanol and in cumene with a mercury lamp filtered through Pyrex. The principal products are benzoin, 1,2,3,4-tetraphenyl-2,3-dihydroxybutane-1,4-dione (3), benzoin benzoate, benzaldehyde, benzoic acid, 1,2,3,4-tetraphenyl-2,3-dihydroxybutane-1,4-dione dibenzoate (5), and some unidentified high molecular weight compounds. The yield of 3 is strongly dependent on initial benzil concentration and temperature and on the solvent used. The quantum yield of benzil disappearance depends on initial benzil concentration to a lower limit which varies with solvent. At an initial benzil concentration of 0.083 moles/l, the quantum yield of benzil disappearance is 0.11 in 2-propanol and 0.018 in cyclohexane. Compound 3 does not appear to be formed by a coupling of the appropriate ketyl radicals, as in the benzophenone case but instead, a complex is formed between a benzil molecule and the ketyl radical. Compound 3 decomposes at temperatures as low as 25°. The principal path for the formation of benzaldehyde and benzoyl radicals is the dissociation of the ketyl radical. Excited benzil abstracts a hydrogen from 2-propanol at least ten times faster than it dissociates into two benzoyl radicals.
Oxidative addition of silicon hydrides to hydridocarbonyltris(triphenylphosphine)iridium(I)
Authors: Harrod J. F. , Gilson D. F. R. , Charles R.
Published: May 2006

Complexes have been prepared by oxidation of hydridocarbonyltris(triphenylphosphine)iridium(I) with a variety of silicon hydrides. The complexes were very stable with respect to thermal loss of either silicon hydride or molecular hydrogen.An unequivocal assignment of stereochemistry of the complexes was obtained from a combination of infrared and proton nuclear magnetic resonance (n.m.r.) techniques. Addition of the silicon hydride to the iridium complex was found to be stereospecifically cis.
Thiazoloisoquinolines. III. Structure and methylation of 2-hydroxythiazolo[4,5-c]- and -[5,4-c]isoquinolines
Authors: Hall Catherine E. , Taurins Alfred
Published: May 2006

not available
Synthesis of some methylated tetroses and pentoses
Authors: Dutton G. G. S. , Gibney K. B. , Reid P. E.
Published: May 2006

Oxidation of 2,3-di-O-methyl-D-glucitol (≡ 4,5-di-O-methyl-L-gulitol) and 2,3-di-O-methyl-D-mannitol (≡ 4,5-di-O-methyl-D-mannitol) with an excess of periodate gave 2,3-di-O-methyl-L-threose and 2,3-di-O-methyl-D-erythrose, each characterized as the 2,4-dinitrophenylhydrazone. Borohydride reduction of the sugars gave 2,3-di-O-methyl-L-threitol and 2,3-di-O-methylerythritol characterized as their di-p-nitrobenzoates. Oxidation of the hexitols with 1 mole of periodate gave 3,4-di-O-methyl-L-xylose characterized as methyl 3,4-di-O-methyl-α-L-xylopyranoside and 3,4-di-O-methyl-D-arabinose identified as 3,4-di-O-methyl-D-arabonamide. 2-O-Methyl-D-erythritol (≡ 3-O-methyl-L-erythritol) and 1-O-methyl-D-threitol (≡ 4-O-methyl-D-threitol) were also prepared and characterized as the tri-p-nitrobenzoates.
2-Amino-4-methyl-5-hexenoic acid, a naturally occurring antimetabolite antibiotic
Authors: Kelly R. B. , Martin D. G. , Hanka L. J.
Published: May 2006

A new antimetabolite antibiotic has been isolated from a Streptomyces culture. The antibiotic has been shown to be 2-amino-4-methyl-5-hexenoic acid, a hitherto unknown compound.
Crystal field splitting in the far infrared spectrum of rhombic sulfur
Authors: Anderson A. , Wong L. Y.
Published: May 2006

The infrared (i.r.) spectra of thin polycrystalline samples of orthorhombic sulfur at 95 °K in the range 50–500 cm−1 have been recorded. The three i.r. active fundamentals ν4, ν5, and ν6 are observed to be split into 2,3, and 3 components, respectively, as predicted from a group theoretical analysis of the unit cell symmetry, thus confirming the assignment of ν4 and ν6. Several weaker absorptions are assigned by comparison with recent Raman results and a normal coordinate analysis. No peaks assignable to lattice vibrations are observed.
Primary yields and mechanism in the radiolysis of gaseous ammonia
Authors: Willis C. , Boyd A. W. , Miller O. A.
Published: May 2006

Ammonia vapor has been irradiated with single pulses of electrons at a very high dose rate (1027 eV g−1 s−1) with a Febetron 705. At this dose rate radical–product reactions are not significant. In pure ammonia, hydrogen, nitrogen, and hydrazine are produced and the yields found at 1027 eV g−1 s−1 are: G(H2) = 3.58 ± 0.08; G(N2) = 1.00 ± 0.05; G(N2H4) = 0.58 ± 0.05. The yields are independent of pressure from 1 to 5 atm and of temperature between 20 and 200 °C. Above 250 °C the yields of all three products increase significantly and this is due to reaction [1] competing with radical–radical reactions.[Formula: see text]A rate constant for this reaction has been determined,[Formula: see text]Product yields have been measured for ammonia–propene mixtures. These yields have allowed determination of the primary radiation yields GNH = 0.74; [Formula: see text]; GH = 4.8; and G(−NH3) = 5.4.
Stereochemistry of some olefins RfCH=CHI and the preparation of some new cyclopropenes
Authors: Cullen W. R. , Waldman M. C.
Published: May 2006

The light induced additions of CF3I and C2F5I to acetylene yield the trans 1:1 adducts predominantly [CF3CH=CHI (trans:cis = 6.7:1) and C2F5CH=CHI (trans:cis = 9:1)]. The addition of i-C3F7I to acetylene gives a 1:1 adduct consisting of a higher proportion of the cis isomer (trans:cis = 1.78:1). The i-C3F7I-acetylene adduct can be dehydrohalogenated to produce i-C3F7C≡CH. Difluorocarbene (from (CH3)3SnCF3) does not add to the olefinic 1:1 adducts but does add to the polyfluoroalkyl acetylenes RfC≡CH to produce the cyclopropenes [Formula: see text]
Barriers to rotation in ortho-alkylphenyl substituted 1,3-benzoxazines
Authors: Brownstein S. , Horswill E. C. , Ingold K. U.
Published: May 2006

Four 3,4-dihydro-3-ortho-alkylphenyl-2H-1,3-benzoxazines have been synthesized. Enthalpies and entropies of activation for rotation about the phenyl–nitrogen bond have been calculated from the temperature dependence of the proton resonance spectra for the o-isopropyl (ΔS‡ = −4 e.u., ΔH‡ = 10.8 kcal/mole) and o-t-butyl (ΔS‡ = 0.4 e.u., ΔH‡ = 16.9 kcal/mole) derivatives. The barrier to rotation for the o-methyl and 2,6-dimethyl derivatives was too low to be measured by this procedure.
Etudes stereochimiques. VIII. Sur la serie exo-maleopimarique
Authors: Maciejewski C. , Gillard M. , Langlois N. , Gastambide B.
Published: May 2006

not available
Coordination complexes of acetylene diphosphines. Part III. Silver(I) and mercury(II) complexes
Authors: Anderson W. A. , Carty A. J. , Efraty A.
Published: May 2006

Complexes of bis(diphenylphosphino)acetylene with silver(I) and mercury(II) are described. Infrared and Raman spectra together with chemical evidence suggest that the compounds AgX(DPPA) (X = Cl, Br, I, SCN, NO3; DPPA = bis(diphenylphosphino)acetylene), [AgX]2(DPPA)3 (X = Cl), AgX(DPPA)2 (X = BF4, PF6), and HgX2(DPPA) (X = Cl, Br, I) have polymeric structures with bridging bis(diphenylphosphino)acetylene groups.
Reaction of ethanesulfenyl chloride with 2-methoxy-5,6-dihydro-2H-pyran
Authors: Baldwin M. J. , Brown R. K.
Published: May 2006

The reaction of ethanesulfenyl chloride with 2-methoxy-5,6-dihydro-2H-pyran gives only 4β-chloro-3α-ethylthio-2β-methoxytetrahydropyran. A rationale is presented to explain the observed highly selective reaction.
Gas phase radiolysis of hydrogen chloride, hydrogen bromide, and nitrous oxide with intense electron pulses
Authors: Willis C. , Boyd A. W. , Armstrong D. A.
Published: May 2006

Hydrogen chloride and hydrogen bromide have been irradiated with single electron pulses at a very high intensity (1027 eV g−1 s−1) with a Febetron 705. At room temperature the yields of hydrogen from hydrogen chloride and hydrogen bromide, for pressures between 700 and 1200 Torr, are G(H2) = 8.1 ± 0.2 and G(H2) = 9.9 ± 0.3, respectively. These are the same as the yields observed at low dose rates. Detailed lifetime calculations, however, show that the mechanism is significantly different at the higher dose rate. Scavenger experiments with chlorine in hydrogen chloride show that the negative ion intermediates form thermal hydrogen atoms.The value of G(N2) = 12.4 ± 0.2 from nitrous oxide at a dose rate of 1027 eV g−1 s−1 is confirmed and the use of nitrous oxide as a dosimeter for pulsed electron beams is discussed. The higher nitrogen yield at Febetron dose rates appears to be due to changes in the reactions of electrons.
Absolute rate constants for hydrocarbon autoxidation. XIV. Termination rate constants for tertiary peroxy radicals
Authors: Howard J. A. , Adamic K. , Ingold K. U.
Published: May 2006

Absolute rate constants for chain termination by ten t-peroxy radicals have been measured at 30° by the rotating sector technique, the photochemical pre- and after-effect method, and by electron spin resonance. The different methods generally give results in good agreement with one another. The termination rate constants vary from a low of ∼4 × 102 M−1 s−1 for t-butylperoxy to a high of ∼3 × 104 M−1 s−1 for 1,1-diphenylethylperoxy radicals.
Branched-chain sugar nucleosides. III. 9-(3-Deoxy-3-C-methyl-β-D-allofuranosyl and ribofuranosyl)adenine
Authors: Rosenthal Alex , Sprinzl Matej
Published: May 2006

Condensation of triphenylphosphinemethylene (Wittig reagent) with 5-O-benzyl-1,2-O-isopropyl-idene-α-D-erythro-pentafuranos-3-ulose and with 1,2:5,6-di-O-isopropylidene-α-D-ribo-hexofuranos-3-ulose (1) afforded 5-O-benzyl-1,2-O-isopropylidene-3-deoxy-3-C-methylene-α-D-ribofuranose in 36% yield and 1,2:5,6-di-O-isopropylidene-3-C-methylene-α-D-ribo-hexofuranose (2) in 55% yield, respectively. A detailed study of the affect of reaction conditions on the yield of the unsaturated sugar is described. Hydrogenation of 2 proceeded stereoselectively to yield 4 which was hydrolyzed selectively to the 1,2-O-monoisopropylidene derivative 5. Benzoylation of the latter gave 6 which was converted by acetolysis to the 1,2-diacetate 7. Condensation of this compound with 6-benzamidochloromercuripurine in the presence of titanium tetrachloride followed by deblocking with methanolic sodium meth-oxide, yielded 9-(3-deoxy-3-C-methyl-β-D-allofuranosyl)adenine (10) in 48% yield based on 7. Sodium metaperiodate oxidation of 10, followed by sodium borohydride reduction of the aldehydo derivative, afforded 9-(3-deoxy-3-C-methyl-β-D-ribofuranosyl)adenine (11) in 85% yield.
A study of the complexing of gold(I) with tertiary phosphine, arsine, and stibine
Authors: Westland A. D.
Published: May 2006

The equilibrium[Formula: see text]was studied in nitrobenzene solution and evidence for the occurrence of tricoordinate (Ph3P)2AuX was obtained. The results indicate that π-bonding of phosphine to gold(I) is much stronger than that of phosphine to silver(I). Attempts to prepare tricoordinate complexes from di(tertiary)phosphine or arsine failed. Chloro- and bromo(triphenylstibine)gold(I) have been prepared. The dipole moments of Ph3-MAuX, where M = P or As, and X = Cl, Br, and I, or M = Sb and X = Br have been determined. Metal–ligand stretching frequencies are compared.
Hydrogen bonding in lidocaine salts. I. The stretching band and its dependence on the associated anion
Authors: Neville George A. , Regnier Zephyr R.
Published: May 2006

By means of deuterium exchange, the [Formula: see text] band was identified in a series of lidocaine salts with varying anionic size. A value for the free [Formula: see text] stretching frequency was obtained which permitted [Formula: see text] to be related to anionic radius. Similar relationships were found for triethylamine and pyridinium salts using frequency data available in the literature. Four new lidocaine salts (HI, CF3CO2H, HAsF6, and HSbCl6) are reported.
A 14N nuclear magnetic resonance study on nitrogen–oxygen–halogen compounds
Authors: Qureshi A. M. , Ripmeester J. A. , Aubke F.
Published: May 2006

14N nuclear magnetic resonance spectra of nitrogen oxides, fluorides, and oxyhalides have been recorded using direct measurement with a broad line nuclear magnetic resonance spectrometer. Also investigated are some nitrogen-containing fluoro- and oxo-cations in protonic solvents. Using the side band technique, fine structure due to 14N–19F spin–pin interaction could be resolved for nitrogen trifluoride, nitrogenoxide trifluoride, and nitrylfluoride.
Photo-addition of indene and acrylonitrile: orientation and stereochemistry of the cycloadducts
Authors: Bowman R. M. , McCullough J. J. , Swenton J. S.
Published: May 2006

The cyclobutanes obtained on photosensitized cyclo-addition of indene and acrylonitrile have been reinvestigated and the structures formerly assigned (1) have been unambiguously confirmed. The photo-addition of indene and cyanoacetylene has been shown to smoothly afford a single adduct, 7-cyano-2,3-benzobicyclo[3.2.0]hepta-2,6-diene.
Organoantimony compounds. II. Studies on tetraphenylantimony(V) derivatives
Authors: Goel R. G.
Published: May 2006

Tetraphenylantimony halides, pseudohalides, carboxylates, nitrate, sulfate, selenate, and chromate have been synthesized. The infrared spectra, molecular weights, and electrical conductances of these compounds have been investigated to elucidate the chemical constitution. The compounds have molecular, monomeric constitution in benzene solutions. Infrared results indicate that with the exception of the acetate and the oxalate, all the compounds have 5-coordinate structures. The acetate is 6-coordinate in the solid state and 5-coordinate in bromoform or chloroform solution. The oxalate is indicated to be 6-coordinate in the solid state as well as in chloroform solution. The electrical conductivities of the bromide, chloride, thiocyanate, trifluoroacetate, and the nitrate in nitromethane correspond to those of 1:1 electrolyte. The conductivities of the other compounds indicate little dissociation in this solvent.