bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Density Functional Study of the Hydrogenation of Ketones Catalysed by Neutral Rhodium‐Diphosphane Complexes
Authors: Agbossou‐Niedercorn Francine , Paul Jean‐François 
Published: September 2006

AbstractThe potential energy profile of RhI‐catalysed hydrogenation of ketones has been computed for the simple model system [Rh{H3POCH2CH2N(H)PH3}(Cl)] using DFT calculations. The general sequence of the catalytic cycle involves coordination of the carbonyl derivative to the neutral RhI complex followed by oxidative addition of molecular hydrogen providing rhodium dihydride intermediates. The latter are converted into alkoxy hydrides by a migratory insertion reaction. Reductive elimination of the alcohol and substitution of the latter by the incoming substrate completes the catalyticcycle. Intermediates and transition states of all catalyticsteps have been located. Two isomeric derivatives bearingthe model substrate have been found for the [Rh{H3POCH2CH2N(H)PH3}(Cl)(H2CO)] complex. Eight diastereomeric pathways have been followed for the cis addition of molecular hydrogen to [Rh{H3POCH2CH2N(H)PH3}(Cl)(H2CO)] leading to eight distinct isomeric dihydride intermediates. Four dihydride complexes can be considered as the more accessible compounds. The site preference for migratory insertion and transition states discriminates the main path of the catalytic reaction. Migratory insertion to form the alkoxy hydride constitute the turn over limiting step of the process. The potential energy profile has been found to be smooth without excessive activation barriers. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthesis and Properties of Organometallic PtII and PtIV Complexes with Acyclic Selenoether and Telluroether Ligands and Selenoether Macrocycles
Authors: Levason William , Manning Joanna M. , Pawelzyk Paul , Reid Gillian 
Published: September 2006

AbstractThe first series of planar dimethyl(selenoether)PtII complexes, [PtMe2L] [L = MeSe(CH2)nSeMe (n = 2 or 3), o‐C6H4(CH2SeMe)2, [8]aneSe2 (1,5‐diselenacyclooctane), or [16]aneSe4 (1,5,9,13‐tetraselenacyclohexadecane)], have been obtained by treatment of [PtMe2(SMe2)2] with L in Et2O solution and characterised by VT 1H, 13C{1H}, 77Se{1H} and 195Pt{1H} NMR spectroscopy, electrospray MS and microanalysis. The corresponding dimethyl(telluroether)PtII complexes do not form under similar reaction conditions. The distorted octahedral [PtMe3I(L)] [L = o‐C6H4(CH2SeMe)2, [8]aneSe2, [16]aneSe4 or MeC(CH2SeMe)3] form as stable complexes in good yield from reaction of PtMe3I with L in refluxing CHCl3 and have been characterised similarly. These all show bidentate selenoether coordination, with fast pyramidal inversion occurring at room temperature. The distorted octahedral coordination environment at PtIV is also confirmed from a crystal structure of [PtMe3I{o‐C6H4(CH2SeMe)2}]. Rare examples of (telluroether)PtIV complexes, [PtMe3I{o‐C6H4(CH2TeMe)2}] and the dinuclear [Me3Pt(μ2‐I)2(μ2‐MeTeCH2TeMe)PtMe3], have also been prepared and characterised similarly (and also by 125Te{1H} NMR spectroscopy). The [8]aneSe2 and [16]aneSe4 species are the first examples of alkyl PtII or PtIV complexes with (macro)cyclic selenoether coordination. Halide abstraction (TlPF6) from [PtMe3I(κ2‐[16]aneSe4)] affords [PtMe3(κ3‐[16]aneSe4)]PF6; a rare example of a cationic PtIV selenoether. The (diselenoether)PtII complexes undergo oxidative addition of MeI to yield the corresponding PtIV species [PtMe3I(diselenoether)]. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Click Chemistry with an Active Site Variant of Azurin
Authors: de Jongh Thyra E. , van Roon Anne‐Marie M. , Prudêncio Miguel , Ubbink Marcellus , Canters Gerard W. 
Published: September 2006

AbstractThe active site of the blue copper protein azurin (Azu) from Pseudomonas aeruginosa consists of a Cu ion immobilized by bonds to four amino acid side chains. The protein assists in electron transfer in vivo. Replacement of Cu‐ligand His117 by a Gly makes the Cu site accessible for exogenous ligands. Incubation of the H117G Azu with n‐alkane linkers carrying imidazole groups at opposite ends leads to the formation of noncovalently linked Azu dimers. The active site of H117G Azu is vulnerable to Cu‐catalyzed oxidative attack. Replacement of CuII by ZnII leads to stable dimers, whose structures have been determined by X‐ray diffraction. These structures are reported here. The similarity in the structure of the active site between the wild type (wt) Zn‐Azu and the dimer is remarkable in light of the different relation of the coordinating imidazole to the protein framework (covalently attached vs. exogenous origin, respectively). The part of the “ligand loop” running from amino acid 116 to 121 has acquired increased flexibility in the mutant. The connected subunits have adopted an unexpected orientation relative to each other.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Synthetic Studies on Cyathin Terpenoids: Enantioselective Synthesis of the Tricyclic Core of Cyathin through Intramolecular Heck Cyclisation
Authors: Drège Emmanuelle , Tominiaux Cyrille , Morgant Georges , Desmaële Didier 
Published: September 2006

AbstractAn enantioselective synthesis of the tricyclic ketone (+)‐5, which displays the carbon core of NGF‐inducing cyathane diterpenes, has been completed according to a strategy in which the key step was the intramolecular Heck reaction of the AC subunit 49 establishing the crucial anti stereochemical relationship between the two angular substituents. The C‐9 quaternary centre was set up by taking advantage of the enantioselective Michael addition involving chiral imines providing keto ester (R)‐10 in 91 % ee. After incorporation of the isopropyl group and iododecarboxylation of the propionate side chain, the iodo ketone 39 was condensed with the lithium enolate of methyl dihydrobenzoate to give the AC subunit 43 which was further elaborated to triflate (–)‐22. While direct Heck cyclisation of 22 was ineffective, oxidation of the bis(allylic) position of the 1,4‐cyclohexadiene moiety enhanced the reactivity, allowing the stereoselective formation of the hexahydro‐cyclopenta[a]naphthalene (+)‐50a. A key element of the construction was the final C ring enlargement, involving trimethylaluminum‐promoted one‐carbon expansion of ketone 52 with trimethylsilyldiazomethane which provided the tricyclic ketone (+)‐5. Furthermore, epoxidation of trienone (+)‐50a was shown to occur exclusively on the β face, giving rise to the C‐14 functionalised advanced intermediate 51 which has considerable potential for the synthesis of natural cyathins and analogues.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Superacidic Activation of Maleimide and Phthalimide and Their Reactions with Cyclohexane and Arenes
Authors: Koltunov Konstantin Yu. , Prakash G. K. Surya , Rasul Golam , Olah George A. 
Published: September 2006

AbstractWhen activated in the CF3SO3H/SbF5 acid system maleimide (1) and phthalimide (2) undergo selective ionic hydrogenation with cyclohexane to give 1,5‐dihydropyrrol‐2‐one (3) and phthalimidine (11), respectively. When treated with aluminum halides, N‐phenylmaleimide (4) reacts with cyclohexane to give N‐phenylsuccinimide (5), whereas 2 still gives 11. Imide 1 also condenses with benzene in trifluoromethanesulfonic acid (CF3SO3H) to give 1,5‐dihydro‐5,5‐diphenylpyrrol‐2‐one (7) as the major product. However, in the presence of aluminum halides 1 reacts with benzene, toluene, and o‐dichlorobenzene to give 3‐arylsuccinimides 8–10, respectively. Imide 2 reacts with benzene under the influence of trifluoromethanesulfonic acid as well as aluminum halides to yield 3,3‐diphenylphthalimidine (12). The mechanism of these reactions, with potential involvement of superelectrophilic dicationic intermediates, is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Rhodium‐Catalyzed Hydroboration Reactions with Sulfur and Nitrogen Analogues of Catecholborane
Authors: Hadebe Siphamandla W. , Robinson Ross S. 
Published: September 2006

AbstractRhodium‐catalyzed hydroboration of 1‐octene and trans‐4‐octene with sulfur‐ and nitrogen analogues of catecholborane are demonstrated with the use of in situ 11B NMR spectroscopy. Our study shows that the sulfur‐ and nitrogen analogues are significantly less prone to disproportionation than catechol, which results in enhanced yields of the desired compounds.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Interactions between sediment delivery, channel change, climate change and flood risk in a temperate upland environment
Authors: Lane S. N. , Tayefi V. , Reid S. C. , Yu D. , Hardy R. J. 
Published: September 2006

AbstractThis paper uses numerical simulation of flood inundation based on a coupled one‐dimensional–two‐dimensional treatment to explore the impacts upon flood extent of both long‐term climate changes, predicted to the 2050s and 2080s, and short‐term river channel changes in response to sediment delivery, for a temperate upland gravel‐bed river. Results show that 16 months of measured in‐channel sedimentation in an upland gravel‐bed river cause about half of the increase in inundation extent that was simulated to arise from climate change. Consideration of the joint impacts of climate change and sedimentation emphasized the non‐linear nature of system response, and the possibly severe and synergistic effects that come from combined direct effects of climate change and sediment delivery. Such effects are likely to be exacerbated further as a result of the impacts of climate change upon coarse sediment delivery. In generic terms, these processes are commonly overlooked in flood risk mapping exercises and are likely to be important in any river system where there are high rates of sediment delivery and long‐term transfer of sediment to floodplain storage (i.e. alluviation involving active channel aggradation and migration). Similarly, attempts to reduce channel migration through river bank stabilization are likely to exacerbate this process as without bank erosion, channel capacity cannot be maintained. Finally, many flood risk mapping studies rely upon calibration based upon combining contemporary bed surveys with historical flood outlines, and this will lead to underestimation of the magnitude and frequency of floodplain inundation in an aggrading system for a flood of a given magnitude. Copyright © 2006 John Wiley & Sons, Ltd.
Are forecasters reluctant to revise their predictions? Some German evidence
Authors: Kirchgässner Gebhard , Müller Ulrich K. 
Published: September 2006

AbstractPeople are reluctant to admit mistakes. This could also be true of economic forecasters. If revisions of past forecasts are costly, then it will become optimal for forecasters to only partially adjust a past forecast in the light of new information. The unwillingness to admit to the mistake in the old forecast generates a bias of the new forecast in the direction of the old forecast. We test this hypothesis for the joint predictions of the Association of German Economic Research Institutes over the last 35 years. We find some evidence for such a bias and compute the implied unwillingness to revise forecasts.  Copyright © 2006 John Wiley & Sons, Ltd.
A de novo MLH1 germ line mutation in a 31‐year‐old colorectal cancer patient
Authors: Plasilova Martina , Zhang Jian , Okhowat Roberta , Marra Giancarlo , Mettler Markus , Mueller Hansjakob , Heinimann Karl 
Published: September 2006

AbstractHereditary nonpolyposis colorectal cancer is an autosomal dominant cancer predisposition syndrome caused by inherited germ line mutations in DNA mismatch repair genes, predominantly MSH2 and MLH1. Here we report the first proven de novo germ line mutation in MLH1 (c.666dupA) identified in a 31‐year‐old colorectal cancer patient with the alteration being present in a heterozygous state in all three germ layers and homozygously in his colon cancer. The mutation was absent in both biological parents and all sibs available. Despite extensive polymorphic marker analysis, the parental origin of c.666dupA could not be conclusively determined, representing either a single mutational event in a parental germ cell or (maternal) gonadal mosaicism. Although rare, consequential application of the Bethesda guidelines for genetic testing should allow the clinician to readily identify colorectal cancer patients below age 50 years who carry de novo mismatch repair gene mutations. © 2006 Wiley‐Liss, Inc.
Detection in primary chronic myeloid leukaemia cells of p210BCR‐ABL1 in complexes with adaptor proteins CBL, CRKL, and GRB2
Authors: Patel Hetal , Marley Stephen B. , Gordon Myrtle Y. 
Published: September 2006

AbstractChronic myeloid leukemia (CML) arises as a consequence of the expression of a chimeric fusion protein, p210BCR‐ABL1, which is localized to the cytoplasm and has constitutive protein tyrosine kinase activity. Extensive publications report that p210BCR‐ABL1 complexed with multiple cytoplasmic proteins can modulate several cell signaling pathways. However, while altered signaling states can be demonstrated in primary CML material, most of the reported analytical work on complexed proteins has been done in cell lines expressing p210BCR‐ABL1. This has been necessary because primary hemopoietic cell lysates contain a degradative activity which rapidly and permanently destroys p210BCR‐ABL1, precluding accurate p210BCR‐ABL1 quantification by Western blotting or investigation of coimmunoprecipitating proteins in primary cells. This degradative activity has proven intractable to inhibition by conventional protease inhibitors. We show here that the degradative activity in primary cells is associated with cell lysosomes and is most likely to be an acid‐dependent hydrolase. By lysing primary hemopoietic cells at high pH, we have demonstrated substantial inhibition of the p210BCR‐ABL1‐degradative activity and now report, to the best of our knowledge, the first published demonstration by coimmunoprecipitation of the association between p210BCR‐ABL1 and cytoplasmic effector proteins in primary CML material. © 2006 Wiley‐Liss, Inc.
Predicting the onset of major depressive disorder and dysthymia in older adults with subthreshold depression: a community based study
Authors: Cuijpers Pim , Beekman Aartjan , Smit Filip , Deeg Dorly 
Published: September 2006

AbstractBackgroundIt is well‐established that the incidence of major depressive disorder is increased in subjects with subthreshold depression. A new research area focuses on the possibilities of preventing the onset of major depressive disorders in subjects with subthreshold depression. An important research question for this research area is which subjects with subthreshold depression will develop a full‐blown depressive disorder and which will not.MethodsWe selected 154 older subjects with subthreshold depression (CES‐D > 16) but no DSM mood disorder from a longitudinal study among a large population based cohort aged between 55 and 85 years in The Netherlands. Of these subjects, 31 (20.1%) developed a mood disorder (major depression and/or dysthymia) at three‐year or six‐year follow‐up. We examined risk factors and individual symptoms of mood disorder as predictors of onset of mood disorder.ResultsTwo variables were found to be significant predictors in both bivariate and multivariate analyses: eating problems and sleep problems. The incidence of mood disorders differed strongly for different subpopulations, varying from 9% (for those not having any of the two risk factors) to 57% (for those having both risk factors).ConclusionsIt appears to be possible to predict to a certain degree whether a subject with subthreshold depression will develop a mood disorder during the following years. Copyright © 2006 John Wiley & Sons, Ltd.
Processing of emotionally toned pictures in dementia
Authors: Eling P. A. T. M. , Maes J. H. R. , Van Haaf M. 
Published: September 2006

AbstractBackgroundApathy is a common symptom in dementia and is often associated with reduced emotional reactivity. This study examined whether reduced emotional reactivity can be demonstrated in dementia patients using a picture viewing task.MethodsThe viewing time of three different types of visual stimuli was measured in 24 elderly participants, half of which suffered from dementia. The participants had to make a target response to an emotionally neutral target stimulus that was intermixed with a frequently occurring non‐target or ‘background’ stimulus and infrequently presented emotional stimuli. All participants could control the presentation time of each stimulus, but one half of the participants were explicitly instructed to perform the task quickly.ResultsThe main measure was a ratio score in which the viewing time for emotional stimuli was expressed relative to the viewing time for the neutral non‐target stimulus. Using this measure, the instigation of a time‐pressure condition proved to significantly reduce the viewing time for emotional stimuli in the healthy subjects. Irrespective of time‐pressure condition, the dementia patients showed a similar short viewing time for emotional stimuli as did the healthy subjects in the time‐pressure condition. However, both dementia patients and healthy controls displayed longer viewing times for unpleasant than for pleasant stimuli.ConclusionThese results suggest the ability of the present task to reveal the simultaneous occurrence of an overall reduced interest for novel stimuli and an intact differential emotional reactivity to stimuli with a negative versus positive valence in the dementia patients. Copyright © 2006 John Wiley & Sons, Ltd.
A preliminary study of the diagnostic accuracy of the Gerontological Personality disorders Scale (GPS)
Authors: van Alphen S. P. J. , Engelen G. J. J. A. , Kuin Y. , Hoijtink H. J. A. , Derksen J. J. L. 
Published: September 2006

AbstractBackgroundThere is still a lack of diagnostic instruments that are specifically developed to diagnose personality disorders in the elderly.ObjectiveTo develop a reliable and valid screening instrument to assess personality disorders in older adults.MethodThe draft version of the screening instrument (52 items) consists of two sections: one for patients and one for informants. The diagnostic accuracy of the instrument has been assessed in the Netherlands in 159 elderly patients in an ambulatory department of geriatric psychiatry and 96 informants.ResultsIn the patient section, sixteen items had a reasonable score for both sensitivity and specificity (approx. 70%). The internal consistency was moderate for habitual behavior (HAB; 7 items) and good for biographical information (BIO; 9 items). The test and retest reliability was moderate for HAB and excellent for BIO. The informant section, on the other hand, had a low score for sensitivity (45%) and a good score for specificity (78%).ConclusionA specific instrument has been developed to diagnose personality disorders in older adults. However, further research is necessary to improve the diagnostic accuracy of the Gerontological Personality disorders Scale (GPS). Copyright © 2006 John Wiley & Sons, Ltd.
Do caregivers' experiences correspond with the concerns raised in the literature? Ethical issues relating to anti‐dementia drugs
Authors: Huizing Anna R. , Berghmans Ron L.P. , Widdershoven Guy A.M. , Verhey Frans R.J. 
Published: September 2006

AbstractBackgroundThe use of Cholinesterase inhibitors (ChE‐Is) has raised debate in the literature on the ethical issues of drug treatment in dementia patients. These issues concern the quality of life of dementia patients and the process of decision‐making regarding the use of ChE‐Is. We interviewed caregivers of patients with dementia, focussing on issues of quality of life and the process of decision‐making regarding the use of anti‐dementia drugs.AimThe aim of this article is to explore whether the ethical concerns raised in the literature are actually in line with experiences in the daily practice of dementia care.MethodsQualitative data that have been collected by semi‐structured interviews with 12 caregivers of patients who (had) used ChE‐Is.ResultsThe results seem to indicate that theoretical considerations should be modified in the light of the reported experiences of caregivers. For example, problematic consequences of an early diagnosis and the creation of unreasonable hope did not appear in the study. Also problems concerning the rising awareness of cognitive decline were not found.ConclusionIn the interest of an ongoing ethical debate on the development and use of anti‐dementia drugs it is important to further specify theoretical issues and to conduct empirical research into the practice of decision making and to get more insight in the perspectives of the patients using anti‐dementia medicines themselves. Copyright © 2006 John Wiley & Sons, Ltd.
A cross‐sectional study on the health related quality of life of depressed Chinese older people in Shanghai
Authors: Chan Sally Wai‐chi , Shoumei J. I. A. , Thompson David R. , Yan H. U. , Chiu Helen F. K. , Chien Wai‐tong , Lam Linda 
Published: September 2006

AbstractBackgroundWith an increasing life expectancy, there is a rapidly growing sector that is aging. Depression is the most prevalent functional mental disorder of older population. It is estimated that about 21% of the older population in Shanghai are suffering from depression.AimThis study investigated the self‐rated health related quality of life of community‐dwelling older people diagnosed with depression in Shanghai, and to examine the relationships between this and mental and physical health, functional status and social support.MethodsA cross‐sectional survey was conducted in two community centres with a convenience sample of 71 participants. Measures included subjective perception of health related quality of life, level of depression, cognitive function, number of medical conditions, activities of daily living, functional abilities, and social support. The majority of the participants were female (n = 52, 73.23%), and married (n = 51, 71.8%).ResultsA higher level of depression was related to a poorer health related quality of life. Participants were least satisfied with their physical health. The level of depression, activities of daily living and satisfaction with social support were predictors of health related quality of life ratings.ConclusionThe study identified how depression affects the bio‐psychosocial status of Chinese older people. Findings are discussed in light of the socio‐cultural environment in Shanghai. Copyright © 2006 John Wiley & Sons, Ltd.
Effect of a qigong exercise programme on elderly with depression
Authors: Tsang Hector W. H. , Fung Kelvin M. T. , Chan Ashley S. M. , Lee Grace , Chan Fong 
Published: September 2006

AbstractObjectivesThis report released findings of a randomized controlled trial conducted in Hong Kong to further our understanding of the psychosocial effects of qigong on elderly persons with depression.DesignEighty‐two participants with a diagnosis of depression or obvious features of depression were recruited and randomly assigned into the intervention and comparison group. The intervention group was given a 16‐week period of Qigong practice while the comparison group participated in a newspaper reading group with same duration and frequency.ResultsAfter eight weeks of qigong practice, the intervention group participants outstripped themselves in improvement in mood, self‐efficacy and personal well being, and physical and social domains of self‐concept when compared with comparison subjects. After 16 weeks of practice, the improvement generalized to the daily task domain of the self‐concept.ConclusionsThis report shows that regular qigong practice could relieve depression, improve self‐efficacy and personal well being among elderly persons with chronic physical illness and depression. Copyright © 2006 John Wiley & Sons, Ltd.