bluuebunny/crossref_metadata_2025 huggingface dataset:
Evolutionary modal identification utilizing coupled shear–flexural response—implication for multistory buildings. Part I : Theory
Authors: Alimoradi Arzhang , Miranda Eduardo , Taghavi Shahram , Naeim Farzad
Published: May 2006

A novel solution of dynamic response of multistory buildings is utilized in an evolutionary system identification algorithm for rapid and robust estimation of dynamic characteristics of instrumented building structures. The empirical characteristics obtained can be used for detection of possible seismic damage and for validating design assumptions with actual recorded structural response. Most structural identification procedures proposed to date only provide some estimates of the modal quantities from which inference to commencement of damage may not be trivial. In this proposed method, besides modal properties such as mode shapes and periods, an overall estimate of the participation of shear to flexural deformations in the lateral response of a building structure is examined. Therefore, any alteration in the mode of response between flexural and shear dominated can be monitored in a time‐varying fashion. The method is fully automated such that it can be used virtually without any delay in the aftermath of an urban earthquake. In a companion paper (Alimoradi and Naeim, 2006), the application of the proposed methodology and its capabilities are exhibited through numerous examples on building structures shaken by multiple earthquakes in their lives; many of them are amongst the most intensively studied instrumented building worldwide. The structural identification work presented here is a component of a comprehensive structural health‐monitoring system for instrumented building structures. Copyright © 2006 John Wiley & Sons, Ltd.
Icy relations: the emergence of South American Antarctica during the Second World War
Authors: Howkins Adrian
Published: May 2006

During the Second World War, both Chile and Argentina advanced sovereignty claims to the Antarctic Peninsula and surrounding sub-Antarctic islands that overlapped substantially with claims that the United Kingdom had made in 1908 and 1917. This article explores the emergence of the concept of a South American Antarctica during this period. Although, at one level, the two South American countries attempted to create a united front against the British, they actually decided to press their claims to Antarctica for different and sometimes conflicting reasons. In Argentina, nationalists connected the question of sovereignty in Antarctica with their claims to the Malvinas and with a broader struggle against a supposed British economic imperialism. In Chile, patriotic officials were less concerned with British claims to the Antarctic Peninsula and more worried about Argentina's growing interest in the region. The article concludes that a better understanding of the complex and contradictory history of the emergence of the idea of South American Antarctica during the Second World War leads to an enhanced appreciation of the subsequent development of the so-called ‘Antarctic Problem’ as it developed over the next 15 years. In order to avoid the artificiality of the term ‘Falklands (Malvinas)’, the British terms ‘Falklands’ and ‘Falkland Islands’ have been used when discussing the United Kingdom's position, and the Argentine term ‘Malvinas’ when discussing that of Argentina.
Soft case-based reasoning
Authors: CHEETHAM WILLIAM , SHIU SIMON , WEBER ROSINA O.
Published: May 2006

The aim of this commentary is to discuss the contribution of soft computing—a consortium of fuzzy logic, neural network theory, evolutionary computing, and probabilistic reasoning—to the development of case-based reasoning (CBR) systems. We will describe how soft computing has been used in case representation, retrieval, adaptation, reuse, and case-base maintenance, and then present a brief summary of six CBR applications that use soft computing techniques.
Some Attitudes to BS 5750: A Study
Authors: Whittington D.
Published: May 2006

The UK manufacturing industry may want quality systems based on BS 5750, but often for the wrong reasons. Quality managers are usually interested in implementing BS 5750 but need the interest and assistance of other managers in order to make it work effectively. Managers and employees other than from quality departments frequently do not consider quality as a major part, or even a minor part, of their job. These attitudes are discussed in the context of a survey of manufacturing companies in the East Midlands.
Social Economic Aspects of India's Development
Authors: Thanawala Kishor
Published: May 2006

India was a colony of Great Britain until 1947 when the
subcontinent was partitioned into two politically separate and
independent countries: India and Pakistan. The partition resulted in a
major political and economic upheaval in the subcontinent. In 1950, a
planning commission was set up to determine priorities and co‐ordinate
Indian economic development. The system has been called a “mixed
economy” as opposed to either a centrally planned economy or an
essentially free marketdriven system. Over the years, the principal
objectives of planned development have been to build up within a
democratic context: (1) a rapidly expanding and technologically
progressive economy, and (2) a social order based on justice and
offering equal opportunity to every person. Several of the achievements
and the problems faced in the course of the development effort are
discussed.
Prospects of Chinese Wage Reform: A Synergy of Market and Planning Systems
Authors: Sun Li‐Teh , Zhang Shi‐Ying , Ge Minghao
Published: May 2006

Wage reform is an important aspect of Chinese economic reform. The
success of wage reform is likely to depend upon the following
understanding: Neither use of the efficiency‐oriented market wage system
nor use of the equity‐oriented planned wage system can solve the dual
problem of economic growth and income distribution. A synergy of the two
systems will therefore be needed. Such a synergetic wage system, which
simultaneously solves the dual problem of production and distribution,
can expedite the rise of social productivity – the fundamental
mission in the preliminary stage of Chinese socialism. In other words,
wages should be differentiated, and the differences should be related to
workers′ effort and society′s demand for them. These differences,
however, need not be very large.
Integrated Materials Management: A Conceptual Approach
Authors: Kathawala Yunus , Nauo Heino H.
Published: May 2006

The role and strategy of integrated materials management are
reviewed. The impact of the concept is then considered in relation to
the traditional functional structure of many companies. A strategy for
the introduction of integrated materials management into a company is
outlined and the benefits and constraints of the concept are considered.
Evaluating Logistics Decisions
Authors: Kleinsorge Ilene K. , Schary Philip B. , Tanner Ray
Published: May 2006

The lack of adequate information for logistics decisions and
evaluating is a major problem for management. This article describes how
linear programming is used to provide methodology to evaluate decisions
and system performance without the availability of cost and other data.
A simple application to logistics systems is discussed and its
application to an actual problem is described.
Don′t Write Off Global Advertising: A Commentary
Authors: Peebles Dean M.
Published: May 2006

Some thoughts on the standardisation of advertising in global
markets are offered. These support a globalised perspective in
international advertising.
Why State Corporations in Developing Countries Have Failed
to Attract Foreign Investment
Authors: Stoever William A.
Published: May 2006

This article examines the behavioural and organisational reasons
why the investment promotion materials of state‐owned enterprises in
some developing countries are very poor as marketing literature. It
gives examples selected from nine LDCs′ publications to illustrate
specific ways in which they are inappropriate: by focusing on the
enterprise′s own concerns rather than the concerns of potential
investors; by acting as a rule enforcer rather than a facilitator for
foreign companies; by addressing the wrong audience or learning the
wrong lessons from past experiences, etc. The appendix gives suggestions
for how the same contents could be presented in more dynamic and
attractive language.
Culture and Conflict in Academic Organisation: Symbolic
Aspects of University Worlds
Authors: Harman Kay M.
Published: May 2006

How the concept of organisational culture was applied to a recent
study of academic organisations in an Australian university is the
thrust of this article. Rather than use the more traditional approach of
analysing functions and formal structures, the study added a different
perspective by applying a cultural framework adapted chiefly from the
works of three noted scholars of higher education. It examined academic
culture, namely, the symbolic dimension of academic organisation
embodying the traditions, myths, rituals, occupational beliefs and
values and other forms of expressive symbolism that have grown up about
universities and the life and work of academics. Different levels of
culture are revealed, bases of conflict and aspects of a common culture
are elucidated, their organisational implications are discussed and the
value of a cultural perspective is addressed.
Efficiency in Service Delivery: Technological or Humanistic
Approaches?
Authors: Kelley Scott W.
Published: May 2006

Explains that efficient service delivery can often present a
problem for marketers due to the nature of the services. Summarizes the
two general methods already suggested for improving the efficiency of
service delivery – technological and humanistic. Discusses
managerial guidelines for the implementation of these approaches to
service delivery in several service industries, based on two service
classification schemes.
Patient Advice and Liaison Services: strengthening the voices of individual service users in health‐care organizations
Authors: Abbott Stephen , Meyer Julienne , Bentley Jane , Lanceley Anne
Published: May 2006

Objective  To explore the roles of Patient Advice and Liaison Services (PALS) in their interactions with service users.

Context  Every National Health Service health‐care provider in England now has a PALS, which provides service users with information and help in resolving concerns and dissatisfactions with health care.

Design  Longitudinal qualitative study, 2002–4. This paper draws on data from 27 semi‐structured interviews.

Setting and participants  PALS personnel working in six case study PALS in London.

Findings  PALS personnel adopt seven roles in order to support their clients in sorting out problems with health care: information provider; listener; messenger (passing on information from service users to staff); go‐between (passing information forward and back); supporter (helping service users to present their own views); mediator (when two or more parties are in dispute); resource mobilizer (when the support of senior staff or other agencies is necessary to resolve a problem).

Conclusions  Though these are not new functions, PALS is a universal service which is better placed than front‐line health‐care staff to offer such support, and increases choice for service users looking for sources of information and advice.
The value of evidence about past abundance: marine fauna of the Gulf of California through the eyes of 16th to 19th century travellers
Authors: Sáenz‐Arroyo Andrea , Roberts Callum M. , Torre Jorge , Cariño‐Olvera Micheline , Hawkins Julie P.
Published: May 2006

Eyewitness accounts written by early travellers to ‘the new worlds’ provide valuable insights into how seascapes once looked. Although this kind of information has been widely used to chart human impacts on terrestrial ecosystems, it has been greatly overlooked in the marine realm. Here we present a synthesis of 16th to 19th century travellers’ descriptions of the Gulf of California and its marine wildlife. The diaries written by conquerors, pirates, missionaries and naturalists described a place in which whales were ‘innumerable,’ turtles were ‘covering the sea’ and large fish were so abundant that they could be taken by hand. Beds of pearl oysters that are described had disappeared by 1940 and only historical documents reveal the existence of large, widespread, deep pearl oyster reefs, whose ecology and past functions we know little about. Disqualifying the testimonies of early visitors to a region as ‘anecdotal’ is dangerous; it may lead to setting inappropriate management targets that could lead to the extinction of species that are rare today but were once much more abundant. Moreover, it represents unfair historical judgement on the work of early natural historians, scholars and scientists. We suggest that the review and analytical synthesis of reports made by early travellers should become part of the pre‐requisites for deciding how to manage marine ecosystems today.
Proximate mechanisms of male morph determination in the ant Cardiocondyla obscurior
Authors: Schrempf Alexandra , Heinze Jürgen
Published: May 2006

SUMMARY
The ant genus Cardiocondyla is characterized by an extraordinary male polyphenism, with winged disperser males and wingless, territorial ergatoid males. Winged males are produced only after the colony has experienced stressful environmental conditions, e.g., a drastic temperature decrease. We investigated the proximate basis of male polyphenism and caste dimorphism in C. obscurior. The critical stage for both morph and caste determination is the end of the second of three instars. Larval development as well as duration of the pupal stage are extended both in winged males and winged females and winged reproductives need on average 8.8 days longer for the development from egg to adult than wingless ergatoid males and workers. Treatment of first and second instar larvae with methoprene, a juvenile hormone analogue, led to the expression of the winged morph, suggesting an important role of juvenile hormone in both sexes. Although queens are produced year‐round in contrast to winged males, the proximate basis of variation in morphology is likely to be the same in both sexes. Whereas the larvae themselves appear to be insensitive to the environmental changes, behavioral observations revealed that workers react to stress by changing their behavior towards larvae and in this way trigger them to develop into winged males.
Mutationism and the dual causation of evolutionary change
Authors: Stoltzfus Arlin
Published: May 2006

SUMMARY
The rediscovery of Mendel's laws a century ago launched the science that William Bateson called “genetics,” and led to a new view of evolution combining selection, particulate inheritance, and the newly characterized phenomenon of “mutation.” This “mutationist” view clashed with the earlier view of Darwin, and the later “Modern Synthesis,” by allowing discontinuity, and by recognizing mutation (or more properly, mutation‐and‐altered‐development) as a source of creativity, direction, and initiative. By the mid‐20th century, the opposing Modern Synthesis view was a prevailing orthodoxy: under its influence, “evolution” was redefined as “shifting gene frequencies,” that is, the sorting out of pre‐existing variation without new mutations; and the notion that mutation‐and‐altered‐development can exert a predictable influence on the course of evolutionary change was seen as heretical. Nevertheless, mutationist ideas re‐surfaced: the notion of mutational determinants of directionality emerged in molecular evolution by 1962, followed in the 1980s by an interest among evolutionary developmental biologists in a shaping or creative role of developmental propensities of variation, and more recently, a recognition by theoretical evolutionary geneticists of the importance of discontinuity and of new mutations in adaptive dynamics. The synthetic challenge presented by these innovations is to integrate mutation‐and‐altered‐development into a new understanding of the dual causation of evolutionary change—a broader and more predictive understanding that already can lay claim to important empirical and theoretical results—and to develop a research program appropriately emphasizing the emergence of variation as a cause of propensities of evolutionary change.
Type 2 diabetes and risk for periodontal disease: a role for dental health awareness
Authors: Jansson H. , Lindholm E. , Lindh C. , Groop L. , Bratthall G.
Published: May 2006

Background: Several studies have found correlations between diabetes and an increased prevalence of periodontitis.

Objective: To analyse, in a group of subjects with type 2 diabetes (T2D), (i) the association between medical characteristics and severe periodontal disease and (ii) dental care habits and knowledge of oral health.

Methods: One hundred and ninety‐one subjects with T2D were examined. Based on assessment of marginal bone height in panoramic radiographs, two periodontal subgroups were identified: one periodontally diseased (PD+) and one periodontally healthy (PD−) group. All subjects completed a questionnaire about their medical and oral health.

Results: Twenty per cent of the subjects were classified as PD+. This was verified by clinical parameters. PD+ individuals had higher haemoglobin A1c (HbA1c) levels (p=0.033) and higher prevalences of cardiovascular complications (p=0.012). They were also less likely to be of Scandinavian origin (p=0.028) and more likely to smoke (p<0.001) than the PD‐ group.

The PD+ group rated their oral health as poor (p<0.0001) and believed that T2D had an influence on their oral status (p<0.0001).

Conclusion: The best predictor for severe periodontal disease in subjects with T2D is smoking followed by HbA1c levels. T2D subjects should be informed about the increased risk for periodontal disease when suffering from T2D.
Immigration Responses to Global Change in Asia: a Review
Authors: HUGO GRAEME J.
Published: May 2006

There has been a parametric increase in the scale and complexity of global international migration in the last fifteen years. Asia has been prominent in this change with countries in the region being important sources and destinations of migrants. This paper summarises the main developments which are occurring in south‐north migration, student migration, forced migration, north‐north migration and international labour migration. In the transformation of international population movement in the region a most striking feature is the strong pattern of circularity in movement and the networks which are established between origin and destination. It is argued that several global changes have been instrumental in these changes. These include the three ‘Ds’: demography, development and democracy. It is shown that increasing gradients of difference between nations in the pattern of growth (or lack of it), in the workforce, in income and poverty levels and in patterns of governance, have been important drivers of the migration. Moreover they are likely to increase in their impact over the next two decades. In addition, the impact of global environmental change on migration is considered, as are the effects of proliferating social networks and the global migration industry.
Synergies between Farming and Rural Tourism: Evidence from Flanders
Authors: Van Huylenbroeck Guido , Vanslembrouck Isabel , Calus Mieke , Van de Velde Liesbeth
Published: May 2006

Support for rural development and agri‐environment measures is often defended on the basis of the contribution of farming to the attractiveness of rural areas and the growing rural tourism sector. Farmers may benefit from the presence of tourism by offering accommodation or selling farm products to tourists. We analyse rural tourism data for Flanders to determine whether agricultural amenities contribute to the price rural tourists are willing to pay for lodging at a farm. We find that farming practices do indeed influence the attractiveness of an area for tourism and have an impact on the prices that can be charged for accommodation. Amenities from agriculture such as permanent grassland have a positive influence on rental prices. However, the presence of intensive agricultural and livestock farming and associated polluting activities decrease the attractiveness of rural regions for tourism. Farm tourism is found to make an important contribution to the farm income and economy of a rural region. Farm tourism constituted more than 30 per cent of the farm income of certain farms. Overall, our findings support the idea of major synergies between farming and rural tourism. Strengthening this relationship may therefore be a good strategy for countryside management and rural development.
Role of Nitrogen and Carbon Transport, Regulation, and Metabolism Genes for
Saccharomyces cerevisiae
Survival In Vivo
Authors: Kingsbury Joanne M. , Goldstein Alan L. , McCusker John H.
Published: May 2006

Saccharomyces cerevisiae
is both an emerging opportunistic pathogen and a close relative of pathogenic
Candida
species. To better understand the ecology of fungal infection, we investigated the importance of pathways involved in uptake, metabolism, and biosynthesis of nitrogen and carbon compounds for survival of a clinical
S. cerevisiae
strain in a murine host. Potential nitrogen sources in vivo include ammonium, urea, and amino acids, while potential carbon sources include glucose, lactate, pyruvate, and fatty acids. Using mutants unable to either transport or utilize these compounds, we demonstrated that no individual nitrogen source was essential, while glucose was the most significant primary carbon source for yeast survival in vivo. Hydrolysis of the storage carbohydrate glycogen made a slight contribution for in vivo survival compared with a substantial requirement for trehalose hydrolysis. The ability to sense and respond to low glucose concentrations was also important for survival. In contrast, there was little or no requirement in vivo in this assay for any of the nitrogen-sensing pathways, nitrogen catabolite repression, the ammonium- or amino acid-sensing pathways, or general control. By using auxotrophic mutants, we found that some nitrogenous compounds (polyamines, methionine, and lysine) can be acquired from the host, while others (threonine, aromatic amino acids, isoleucine, and valine) must be synthesized by the pathogen. Our studies provide insights into the yeast-host environment interaction and identify potential antifungal drug targets.
Heavy transition metal complexes of biologically important molecules. I. The crystal and molecular structure of trans-dichloro(bis(isopropyl)-sulfoxide-S)(1-methylcytosine-N)platinum(II)
Authors: Lock Colin James Lyne , Speranzini Robert Anthony , Powell John
Published: May 2006

The crystal and molecular structure of trans-dichloro(bis(isopropyl)sulfoxide-S)(1-methylcytosine-N)platinum(II) has been determined by single crystal X-ray diffraction. The crystals are triclinic with a = 16.205(5), b = 8.078(2), c = 6.776(2) Å, α = 106.53(2), β = 96.35(2), γ = 98.54(2)°. The space group is [Formula: see text] and there are two molecules per unit cell. A total of 2294 independent reflections, of which 2023 were observed, were examined on a Syntex [Formula: see text] diffractometer. The structure was refined by full matrix least squares analysis to an R2 value of 0.0427. The ligands form a rough square around the platinum atom with Pt—Cl(1), 2.304(3), Pt—Cl(2), 2.287(4), Pt—S, 2.232(2), Pt—N, 2.058(7). Distances within the ligands are normal. The plane of the cytosine ring is at 84.4° to the plane formed by the ligands around platinum.
A synthesis of methyl lambertianate
Authors: Bell Russell A. , Fétizon Marcel
Published: May 2006

A partial synthesis of methyl lambertianate from the 13-keto-degradation product 1 from methyl agathate is described. The furan ring is synthesized by the method of Burness, and involves hydroxymethyleneation of methyl ketone 1, acetal formation, glycidic ester condensation, and final pyrolysis of the glycidic ester-acetal 5 to give methyl 16-carboxylambertianate. Methyl lambertianate was obtained in moderate yield by copper-quinoline decarboxylation.
Molecular conformations of ortho-substituted benzophenones
Authors: Zuccarello Felice , Millefiori Salvatore , Trovato Salvatore
Published: May 2006

The minimum energy conformations of some mono- and di-substituted benzophenones were determined from contour maps of potential energy calculated by a semiempirical approach. The electrostatic interactions play a relevant role in the relative stabilities when different minima are possible. Comparison with the available experimental data reveals a good agreement with geometrical data, and a poorer agreement with energies in highly strained conformations.
Cysteine-sensitised formation and repair of mixed disulfide in the oxidation of papain by H2O2 and OH radicals
Authors: Lin Wen Shu , Gaucher G. Maurice , Armstrong David A. , Lal Manohar
Published: May 2006

The inactivation of the proteolytic enzyme papain by hydrogen peroxide produces a sulfenic acid by oxidation of the essential SH of cysteine 25 at the enzyme active site:[Formula: see text]The kinetics of repair of this entity by cysteine were consistent with the two reactions:[Formula: see text][Formula: see text]Reaction 4 was the faster with k4 ≥ 800 M−1 s−1, and k5 = 11.3 ± 0.5 M−1 s−1. A computer program was developed to evaluate the contributions of peroxide-inactivation and cysteine-repair when they occur simultaneously in N2O-saturated solutions in the absence of catalase. The yields predicted by this program agreed well with the inactivation caused by peroxide in irradiated systems.The effect of cysteine on the inactivation of papain by OH radicals produced by radiolysis of N2O-saturated solutions containing catalase was also investigated. Protection against permanent inactivation was much more efficient than expected on the basis of a simple competition between cysteine and papain for OH radicals, but there was a marked increase in the yield of repairable damage which was not due to hydrogen peroxide. These observations can be qualitatively accounted for by the reactions:[Formula: see text]The same rate constant was obtained for the repair of PapainCys25SSCys from this source as from the peroxide inactivation and treatment with cysteine. However, there was also evidence for additional cysteine-sensitized production of mixed disulfide and this probably occurs through reactions of CysS• radicals:[Formula: see text]
The pulse radiolysis of 1-propanol at 147 to 300 K
Authors: Gilles L. , Boyd A. W.
Published: May 2006

Using ∼20 ns electron pulses the spectra and kinetics of the electron and an absorption in the uv in 1-propanol have been determined at temperatures from 147 to 300 K. The uv absorption is attributed to the hydroxy propyl radical, CH3CH2ĊHOH; it is formed within ∼20 ns over this temperature range and disappears by second order kinetics. The results for the formation of the solvated electron are in agreement with those of Baxendale and Wardman. The temperature dependence of both the radical–radical reaction and the reaction of the solvated electron with N2O is very nearly the same as that of T/η.
Esters chromiques dérivés du tertiobutanol
Authors: Hachey Jean-Marie , Ghali Hélène , Savard Jean-Baptiste
Published: May 2006

The composition of the mixture of chromate esters obtained from the reaction between tert-butyl alcohol and increasing amounts of chromium trioxide has been calculated from the pmr spectrum and confirmed through the determination of the chromium content of these mixtures. The chromate esters formed are the ditertiarybutyl mono-, di-, and trichromate.
Nematic phase nuclear magnetic resonance studies of the molecular structures of cyclobutanone and methylenecyclobutane
Authors: Cole K. C. , Gilson D. F. R.
Published: May 2006

The nematic phase proton magnetic resonance spectra of cyclobutanone and methylenecyclobutane have been analyzed and the direct dipole coupling constants corrected for the averaging effects of the ring puckering vibrations. The nmr data have been used in conjunction with microwave spectroscopic results to derive the molecular structures.
Polymorphism in n-alkylammonium chlorides: X-ray powder diffraction studies
Authors: Gilson D. F. R. , Kertes A. S. , Manley R. St. J. , Tsau J. , Donnay G.
Published: May 2006

The n-alkylammonium halides which have thermal transitions above room temperature adopt either a monoclinic or an orthorhombic form when recrystallized at temperatures below the lowest transition. On heating a transition to a tetragonal structure occurs but on subsequent cooling the crystals do not return to their original form but to a different monoclinic structure.
C-Nucleosides and related compounds. VII. Synthesis of carbocyclic analogues of C-nucleosides
Authors: Just George , Chalard-Faure Bernadette
Published: May 2006

Condensation of lactone 1 and aminoguanadine provides the amino-triazole carbocyclic analogue of C-nucleoside 2a. Lead tetraacetate oxidation of the semicarbazone derivative 4 leads to the amino-oxadiazole derivative 5. Isoxazolines 11 and 12 are obtained by 1,3-dipolar addition of mesitonitrile oxide with the α,β-unsaturated ester 13. Addition of diazomethane onto ester 13 gives the pyrazoline 16 which can be oxidized with bromine to the corresponding carboethoxy-pyrazole 17. The latter is converted to the carboxamido-pyrazole 18 by treatment with ammonia.
1H nuclear magnetic resonance conformational study of medium-sized rings: 3,4-dihydro-1,6-benzodiazocine-2,5-diones
Authors: Elguero José , Fruchier Alain , Llouquet Georges , Marzin Claude
Published: May 2006

From a 1H nmr study it has been possible to show that the eight-membered ring of the N,N′-disubstituted 3,4-dihydro-1,6-benzodiazocine-2,5-diones has a boat conformation, the interconversion barrier of which is slightly over 100 kJ/mol.
A search for protonated cyclobutane
Authors: Lee Choi Chuck , Ko Eric C. F.
Published: May 2006

Attempted protonation of cyclobutane with H2SO4-t or CF3COOH-t failed to give any open chain butyl product as evidence for the formation of protonated cyclobutane. The treatment of cyclobutane with an excess of CF3SO3H-t in a sealed tube at 75 °C for 3 days followed by hydrolysis did give rise to the four isomeric butyl alcohols containing some T-label in the butyl groups. The upper limit for this ring cleavage, probably via protonated cyclobutane, was about 1%. H–T exchange in the recovered cyclobutane was also observed.
Tertiary phosphine complexes of the cobalt(III) NN′-ethylenebis(salicylideneiminato) and bisdimethylglyoximato systems
Authors: Smith C. W. , Loon G. W. Van , Baird M. C.
Published: May 2006

Complexes of the types [CosalenPR3]X, [Cosalen(PR3)2]X, [Co(DH)2PPh3X], and [Co(DH)2(PR3)2]ClO4, many of them new, have been prepared and characterized with respect to 1H nmr spectra, ligand field parameters, and equilibrium constants for the formation of the 2:1 salen complexes. 1H chemical shifts appear to be dominated by anisotropic rather than inductive effects, while the relative tertiary phosphine ligand field strengths appear to correlate with the steric requirements of the phosphines as well as their expected σ donor strengths. Ease of formation of the 2:1 salen complexes is determined largely by steric effects, as are trans effects in the DH systems.
Crystal structure of tetraammonium diphosphate, (NH4)4P2O7 at 22 °C
Authors: Middlemiss Nora , Calvo Crispin
Published: May 2006

Crystals of tetraammonium diphosphate, (NH4)4P2O7, crystallize in the monoclinic system with space group C2/c, Z = 4 and lattice parameters a = 11.758(3), b = 6.486(2), c = 13.659(2) Å and β = 104.81(1)°. The structure was refined using full-matrix least-squares methods with 810 reflections to an R value of 0.092. The diphosphate anion contains a crystallographic two-fold axis, and has a configuration intermediate between staggered and eclipsed. The bridging P—O bond length is 1.624(2) Å and the terminal P—O bonds average 1.507 Å. The diphosphate groups lie in sheets defined by [Formula: see text] and are bridged by NH4+ groups which hydrogen bond to only the terminal oxygen atoms. Each hydrogen is bonded to one oxygen atom but each of the terminal oxygen atoms interacts with either two or three hydrogen atoms.
A deuterium magnetic resonance study of a lamellar lyotropic liquid crystalline phase
Authors: Tracey Alan S. , Diehl Peter
Published: May 2006

Deuterium magnetic resonance spectra have been obtained from the specifically deuterium labelled hydrocarbon chains of a lyotropic lamellar mesophase which spontaneously aligns in a magnetic field. It was found that the behaviour of both the decanol and decylsulphate chains was similar to other lamellar and to nematic phases except that the degrees of order of the chain segment axes were abnormally small, being a factor of four to six less than that observed for other phases. Since the chain behaviour seemed normal it was suggested that the small alignment arose because the preferential orientation of the hydrocarbon chains was not perpendicular to the superstructure of the phase but rather at an angle of about 45° to the normal.
Nuclear charge distribution in the region of symmetric fission of 238U by protons of energy 20–85 MeV
Authors: Sarkar S. , Yaffe L.
Published: May 2006

Independent formation cross sections in the fission of 238U by protons of energy 20–85 MeV were obtained for the nuclides 111Ag, 112Ag, 117In, 115In, 111Pd, and 115Cd. The last three mentioned were estimated on the basis of measurements and isomeric yield data. Charge dispersion curves were constructed and Zp, the most probable charge, determined. The values for (ZA − Zp) lie intermediate between those measured for fission products of higher and lower mass. The number of neutrons emitted was estimated and found to be higher than in asymmetric fission, leading to the conclusion that the former are events arising from higher deposition energies.
Juvabione and its analogues. II. Isolation, identification, and occurrence of juvabiol and its epimer isojuvabiol from the whole wood of Abies balsamea
Authors: Manville John Fieve
Published: May 2006

Epimeric mixtures of juvabiol (3a) and isojuvabiol (4a) have been detected in six North American Abies balsamea (L.) Mill. trees and isolated from the whole-wood extract of three. These juvabione related alcohols are insect juvenile hormone analogues with selective action typical of juvabione (1) and Δ4′-dehydrojuvabione (2). The widespread occurrence of these alcohols indicates that the original 'paper factor' was not due to 1 alone, nor was it due to a mixture of 1 and 2. In addition a fifth IJHA with selective action, Δ3′-dehydrojuvabi-5′-ol (5), was detected in the hot ethanol extract of four trees and isolated from one tree. It is shown that 5 is an allylic rearrangement product of the Δ4′-dehydrojuvabiols 6a and 7a. Mixtures of campesterol and sitosterol are the major crystalline components present in all the petroleum ether soluble extracts.
Complex hydrogen bonded cations. The benzimidazole benzimidazolium cation
Authors: Borah B. , Wood J L.
Published: May 2006

The complex salts (Bz2H)+Y−, Bz = benzimidazole, Y = PF6− or BF4− have been identified in solution, and the molecularity of the fluoroborate, which has been crystallised, confirmed gravimetrically. Infrared and Raman spectra, together with those of the deuterated systems, indicate a similar structure in solution and the crystal, viz., an asymmetric single minimum bridging proton potential, in conformity with the X-ray structure, proving that the pronounced doublet observed in the vs band of the H bridged system is not due to proton tunnelling. The origin of the asymmetric structure is discussed.
[LM(CO)3,4X] complexes of manganese(I) and rhenium(I) with phosphino- and thiophosphinatopyrazole ligands
Authors: Hoyano James , Peterson Louis K.
Published: May 2006

A series of complexes [LM(CO)3X] [Formula: see text] R2pz = pyrazolyl, or 3,5-dimethylpyrazolyl, x = 0–2; M = Mn, X = Cl; M = Re, X = Br) and [Formula: see text] were prepared by the reaction of the appropriate ligand with [M(CO)5X] or [M(CO)4X]2, and were characterized by elemental analysis, solution molecular weight, and infrared, mass, and nmr spectroscopic data. The products are formed via tetracarbonyl intermediates, of which the phosphorus bonded derivative [Formula: see text] was isolated and characterized. The tricarbonyl complexes [LM(CO)3X] and [Formula: see text] adopt a cis-octahedral configuration, in which the ligands form four-, five-, or six-membered chelate structures, via (i) the P atom and the 2-N site of the pyrazolyl moiety, with [Formula: see text], (ii) the sulphur and 2-N atoms, with [Formula: see text], (iii) the 2-N atoms of two pyrazolyl rings, with [Formula: see text] and (iv) the 2-N atoms of three pyrazolyl rings, resulting in a bicyclic system, with P(R2pz)3.The reactions of [CH3Re(CO)5] with [Formula: see text] require forcing conditions, resulting in the simultaneous elimination of carbon monoxide and methane, and yielding a variety of products, including tetracarbonyl, tricarbonyl, and ring-metalated species.
Solvent, concentration, and temperature dependance of the platinum–phosphorus nuclear magnetic résonance coupling constants in cis- and trans-[PtCl2(PBu3n)2]
Authors: Dixon Keith R. , Fakley Martin , Pidcock Alan
Published: May 2006

Studies of the effects of solvent, concentration and temperature on the 31P nmr parameters of cis- and trans-[PtCl2(PBun3)2] are reported. The coupling constants, 1JPt–P are markedly dependent upon all three variables but, in contrast to previous studies on non-coordination compounds, very little corresponding variation in chemical shifts is found. Results are discussed in terms of a solvent cavity model using reaction field, Stark and Macrae effects but it is concluded that a more specific model involving competitive solvation at platinum gives a better interpretation of the data.
Nematic phase nuclear magnetic resonance spectra and vibrationally averaged structures of cyclopropyl chloride, bromide, and cyanide
Authors: Cole K. C. , Gilson D. F. R.
Published: May 2006

The nmr spectra of partially oriented cyclopropyl chloride, bromide, and cyanide have been analysed and the relative proton structure corrected for vibrational effects. The proton structures provide indirect evidence in support of Hoffmann's theory of substituent effects in cyclopropane rings. The distance between protons on the same side of the ring as the substituent is less than the corresponding distance on the other side. The direction of the principal orientation axis in two nematic solvents EBBA and MBBA is the same but the anisotropy of alignment is less in MBBA.
13C T1 nuclear magnetic resonance study of molecular motion: rotational barriers in hindered methyl groups
Authors: Axelson David E. , Holloway Clive E.
Published: May 2006

Analysis of spin–lattice relaxation (T1) data can give information on restricted rotation which is otherwise inaccessible. This study investigates the influence of substituents on the rotation of a neighbouring methyl group in a series of related polycyclic compounds.
Crystal and molecular structure of 8,8-dimethyl-3,5-diphenyl-2,4,6-trioxa-1-azonia-3-bora-5-boranatabicyclo[3.3.0]octane
Authors: Rettig Steven J. , Trotter James , Kliegel W. , Becker H.
Published: May 2006

Crystals of 8,8-dimethyl-3,5-diphenyl-2,4,6-trioxa-1-azonia-3-bora-5-boranatabicyclo[3.3.0]-octane are monoclinic, a = 22.323(1), b = 9.555(1), c = 16.0027(6) Å, β = 109.055(4)°, Z = 8, space group C2/c. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to a final R of 0.048 and Rw of 0.066 for 2629 reflections with I ≥ 3σ(I). The central part of the molecule consists of two fused five-membered rings. One of them is a familiar BOCCN ring while the other is a novel and nearly planar BOBON ring containing one tetrahedral boron atom and one trigonal planar boron atom. Bond lengths are: O—B, 1.337(2)–1.467(2), N—B, 1.692(2), O—N, 1.440(2), O—C, 1.426(2), N—C, 1.513(2), B—C, 1.557(2) and 1.599(2), C(sp3)—C(sp3), 1.520(2)–1.530(2), C—C(ar), 1.372(4)–1.407(2), N—H, 0.89(2), mean C(ar)—H, 0.97(1), and mean C(sp3)—H, 1.01(1) Å. The crystal structure consists of discrete molecules each linked to two others by N—H … O hydrogen bonds (N … O = 2.853(2) Å).
The reaction of catechol and derivatives with potassium superoxide
Authors: Lee-Ruff E. , Lever A. B. P. , Rigaudy J.
Published: May 2006

not available
A new method of quaternizing amines and its use in amino acid and peptide chemistry
Authors: Chen Francis C. M. , Benoiton N. Leo
Published: May 2006

Methyl iodide and potassium bicarbonate in methanol is presented as a mild, efficient, and selective reagent for the quaternization of amino groups. It does not attack hydroxyl groups. Its use with amino acids, derivatives of lysine, and small peptides is described.
The thermally induced rearrangements of 2-vinyloxirane
Authors: Crawford Robert J. , Lutener Stuart B. , Cockcroft Robert D.
Published: May 2006

The kinetics of the gas phase thermolysis of 2-vinyloxirane (4) have been studied over the temperature range 270–310 °C. The racemization of chiral 4 occurs six times faster than the structural isomerization to 2,3-dihydrofuran, (E)- and (Z)-2-butenal, and 3-butenal. The butenals undergo a slow thermolysis to propene and carbon monoxide. cis-Deuterio- and trans-3-deuterio-vinyloxirane have been synthesized and their interconversion is slow. Deuterium kinetic isotope effects on mono- and dideuterio-4 suggest that for the formation of the butenals the rate determining step involves rupture of the oxirane C—O bond. The dihydrofuran is produced by thermolysis of the oxirane C—C bond. The preferred mechanistic interpretation is that a carbon–oxygen diradical serves as an intermediate for butenal formation, and that a carbonyl-ylide is involved in the formation of the dihydrofuran.The relative rates, at 307.4 °C, of cis–trans-5-isomerization:dihydrofuran formation:racemization: butenal formation for 3-deuterio-2-vinyloxirane are 1.0:0.88:40.2:5.94, respectively.
Medium-sized cyclophanes. XX. 13C nuclear magnetic resonance of cyclophanes: p-orbital compression shift and orbital deformation
Authors: Takemura Tetsuo , Sato Takeo
Published: May 2006

The 13C nmr spectra of [2.2]meta-, metapara-, and paracyclophanes were determined. By comparing the chemical shifts with those of acyclic models two types of anomalies were revealed.(1) Bridging methylene carbon resonances for [2.2]metacyclophanes having an alkyl group ortho to the bridge were shifted upfield as a result of van der Waals' compression. The upfield shift is much larger (5–12 ppm) for cyclophanes than for models (2–4 ppm) reflecting the rigid nature of the molecular geometry of the former.(2) Interestingly, inner aryl carbon resonances in [2.2]metacyclophanes and protonated aryl carbon resonances in [2.2]paracyclophanes were shifted downfield by 6–7 ppm. The complementary upfield shift of uncompressed atoms, hydrogen or carbon, connected to those carbons was also noticed. The downfield shift of compressed sp2 carbon results from interaction between two p-orbitals along the same orbital axis, p-orbital compression, and is attributable to decreased electron density.
Molecular motion, phase transitions, and disorder in the pyridinium halides
Authors: Ripmeester John A.
Published: May 2006

The solid pyridinium chloride, bromide, and iodide salts were studied using 1H nuclear magnetic resonance and differential scanning calorimetry. Phase transitions were observed at 345 K for the chloride, 269 K for the bromide, and 247 K for the iodide. Well below each transition, the pyridinium ions are held rigidly in the crystal lattice, whereas above each transition the ions reorientate rapidly about an axis at right angles to the ring planes. From the temperature dependence of the spin–lattice relaxation times the high temperature phase reorientational activation energies were determined to be 1.55, 2.30, and 4.20 kcal/mol for the chloride, bromide, and iodide, respectively.
Enthalpies of solution and single ion enthalpies of transfer from water to dioxane–water mixtures
Authors: Bhatnagar Om N.
Published: May 2006

Standard enthalpies of solutions of sodium bromide, potassium bromide, tetrabutyl phosphonium bromide, tetraphenyl phosphonium bromide, and sodium tetraphenyl boron have been measured in 20%, 44.5%, and 64.5% dioxane–water mixture. On the extra thermodynamic assumption ΔΔHs(Ph4P+) = ΔΔHs(−BPh4) single ion enthalpies of transfer from water to dioxane–water mixtures have been calculated for various ions.
The hydrolysis of substituted benzyl nitrates in water. II. Effect of ortho-substitution
Authors: Koshy Kalavelil Matthew , Robertson Ross Elmore , Dyson George Stanley , Singh Surendra
Published: May 2006

The relative effects of methyl substitution on the rates of hydrolysis of benzyl nitrates in water showed but small differences from earlier reports involving the displacement of Cl− in mixed solvents. The values of the α-deuterium isotope effects for the hydrolysis of the 2,4- and 2,6-dimethyl homologs were similar to that for the p-methylbenzyl nitrate suggesting an approach to limiting hybridization in each case. In spite of this similarity, there was a large negative shift in the value of ΔCP≠ for the hydrolysis of the 2,6-dimethylbenzyl nitrate compared to the values for the 2-methyl and 4-methyl members of the series. The value of ΔCP≠ for the 3-methyl was about the same as for the unsubstituted member. The mechanistic implications of these results while in agreement with the Swain–Thornton reaction rule emphasize the importance of external as well as internal factors in the determination of charge development and separation at the transition state. Steric hindrance or charge dispersal in the cation, or both, in limiting the rate of product formation, delay the attainment of the transition state and hence favor more negative values of ΔCP≠.
ESCA investigations of Group IV derivatives. Part II. Binding-energy predictions for bromo- and iodo-silanes and -germanes
Authors: Drake John E. , Riddle Chris , Henderson H. Ernest , Glavinčevski Boris
Published: May 2006

Core-level binding energies of all atoms are reported for the bromo(methyl)-silanes and -germanes MenMBr4−n (M = Si, Ge; n = 0 → 3) and the iodo(methyl)-silanes and -germanes MenMI4−n (n = 2, 3). Measured binding energy shifts correlate well with values predicted from atomic charge calculations using an electronegativity-equilisation procedure.
La formation de biphénylènes par pyrolyse de mélanges de précurseurs de benzynes
Authors: Martineau André , DeJongh Don C.
Published: May 2006

A new method of forming biphenylenes substituted on one ring is described using gas-phase pyrolysis of mixtures of precursors of appropriate benzynes. The reaction of two benzynes coming from two different sources leads to the formation of the biphenylenes. The mixture of compounds is sublimed into a current of nitrogen and led into an unpacked quartz column heated externally by a furnace.The simultaneous pyrolysis of ninhydrin and tetrachlorophthalic anhydride (molar ratio, 2:1) at 800 °C gives 1,2,3,4-tetrachlorobiphenylene in a 31% yield. The pyrolysis of a mixture of phthalic anhydride and 4-methylphthalic anhydride at 850 °C leads to the formation of 2-methylbiphenylene (molar ratio, 9:1) (16%).
Nuclear magnetic resonance studies. XXX.Hydrogen–deuterium exchange in bicyclo[3.2.1] and -[2.2.2]octenes through allylic and vinylic anions
Authors: Cheng A. K. , Stothers J. B.
Published: May 2006

Bicyclo[3.2.1]oct-2-ene undergoes hydrogen–deuterium exchange through allyl and vinyl carbanionic intermediates under strongly basic conditions, tert-BuO−/tert-BuOD) at 185 °C. Only allylic exchange had been observed in previous studies with tert-BuO−/DMSO. Since the 2-tert-butoxybicyclo[3.2.1]octanes are stable under these conditions an addition–elimination sequence cannot account for exchange at C-3. The relative rates of exchange at C-2, -3, and -4, and the stereoselectivity at the allylic site were determined by 2H nmr. For comparison, the rate of olefinic exchange in bicyclo[2.2.2]octene was also measured.