bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a Q2MM Force Field for the Silver(I)‐Catalyzed Hydroamination of Alkynes
Authors: Donoghue Patrick J. , Kieken Elsa , Helquist Paul , Wiest Olaf 
Published: November 2007

AbstractThe intramolecular hydroamination of carbon‐carbon π‐bonds is an effective method for the rapid construction of nitrogen heterocycles. The rapid evaluation of suitable ligands using virtual screening will aid in the development of a stereoselective analogue of the reaction by predicting effective substrate/ligand combinations. Electronic structure calculations of the relevant transition structures for different nucleophiles and alkynes at the B3LYP/LACVP* level of theory are presented. They provide the basis for the development of a transition state force field by the Q2MM method, which is discussed in detail. The parameter development and performance for the transition state force field is presented.
Study of the Efficiency of Amino‐Functionalized Ruthenium and Ruthenacycle Complexes as Racemization Catalysts in the Dynamic Kinetic Resolution of 1‐Phenylethanol
Authors: Eckert M. , Brethon A. , Li Y.‐X. , Sheldon R. A. , Arends I. W. C. E. 
Published: November 2007

AbstractThe ruthenium‐amino structural motif in ruthenacycles and aminomethylpyridine ruthenium complexes turned out to be a useful basis for the design of readily accessible and active catalysts for the racemization of alcohols. Inspired by the proven ligand acceleration of 2‐aminomethylpyridine (ampy) ligands in ruthenium‐catalyzed hydrogen transfer, the readily accessible ampy‐based oxazolines 8a and 8b were tested and led to novel and active ruthenium racemization catalysts. The highly active ortho‐metalated‐ampy Ru complex 7 was demonstrated to be a fast racemization catalyst (100 % racemization of 1‐phenylethanol at 70 °C within 10 min). When used in the dynamic kinetic resolution of 1‐phenylethanol towards 1‐phenylethyl acetate, the cycloruthenated amine 5 was most active, leading to 86 % of the (R)‐1‐phenylethylacetate with>99 % ee.
Low proportion of male births and low birth weight of sons of flour mill worker fathers
Authors: Milham Samuel , Ossiander Eric M. 
Published: November 2007

AbstractBackgroundThe Washington State Department of Health has collected and coded parental occupation information on birth certificates since 1980. We used these data to search for possible effects of parental occupational exposures on birth outcomes.MethodsWe tabulated sex ratio, birth weight, and proportions of multiple births, still births, and malformations by mothers' and fathers' occupations.ResultsThere were 59 births (22 boys and 37 girls) where the father's occupation was specified as flour mill worker. The sex ratio of 0.373 (95% confidence interval [CI]: 0.261–0.500) was lower than the mean sex ratio of 0.512. The mean birth weight for flour mill workers' boy babies was 3,180 g (95% CI: 2,971–3,389), compared to an overall mean of 3,511 g for all boy babies. The mean birth weight of flour mill workers' girl babies was 3,602 (95% CI: 3,380–3,824), compared to an overall mean of 3,389 for all girl babies.ConclusionThe low prevalence of male infants born to fathers of flour mill workers in Washington State suggests that fumigants that they are exposed to are causing testicular dysfunction. The very low birth weight seen in the male infants of flour mill fathers is unprecedented and may be another genotoxic endpoint. Am. J. Ind. Med. 51:157–158, 2008. © 2007 Wiley‐Liss, Inc.
Factors associated with pesticide safety practices in farmworkers
Authors: Strong Larkin L. , Thompson Beti , Koepsell Thomas D. , Meischke Hendrika 
Published: November 2007

AbstractBackgroundFarmworkers and their families are exposed to pesticides through multiple pathways. Few studies have examined the frequency with which farmworkers engage in pesticide safety practices and the factors associated with their adoption.MethodsUsing a large sample of farmworkers (n = 554), we evaluated relationships between pesticide safety behaviors and farmworkers' beliefs, training history, handling of pesticides at work, perceived occupational exposure, and employers' provision of personal protective equipment.ResultsPerforming behaviors at work was determined largely by whether personal protective equipment was provided. For home behaviors, female gender, living in a labor camp, being trained in the last 5 years, handling pesticides directly, and not perceiving organizational barriers to protecting oneself were associated with taking more precautions.ConclusionsThese findings call for interventions that involve and engage multiple stakeholders to increase adoption of pesticide safety behaviors and reduce pesticide exposure in farmworkers. Am. J. Ind. Med. 51:69–81, 2008. © 2007 Wiley‐Liss, Inc.
Cancer incidence and mortality in aircraft maintenance workers
Authors: D'Este Catherine , Attia John R. , Brown Anthony M. , Gibson Richard , Gibberd Robert , Tavener Meredith , Guest Maya , Horsley Keith , Harrex Warren , Ross James 
Published: November 2007

AbstractBackgroundA cancer incidence and mortality study was conducted in response to health concerns raised by workers from F‐111 aircraft deseal/reseal fuel tank maintenance programs, to determine whether personnel exposed to deseal/reseal had an excess of cancers and mortality.MethodsNumber of deaths and cancers for individuals involved in F‐111 DSRS activities were matched against two Air Force comparison groups. Analyses were weighted to adjust for differences in age, exposure period and rank.ResultsEight hundred seventy‐three exposed, 7,577 comparison group one, and 9,408 comparison group two individuals were matched against death and cancer data, with 431 cancers and 431 deaths. Cancer incidence was higher in the exposed group, with marginally significant increases of 40–50% (cancer incidence rate ratio range 1.45–1.62). Exposed group mortality was significantly lower than both comparison groups, likely due to survivor bias in the exposed group (mortality rate ratio range 0.33–0.44).ConclusionsOn the balance of probabilities, there is an increased risk of cancer associated with participation in F‐111 deseal/reseal activities. Am. J. Ind. Med. 51:16–23, 2008. © 2007 Wiley‐Liss, Inc.
Challenges in residential fall prevention: Insight from apprentice carpenters
Authors: Lipscomb Hester J. , Dale Ann Marie , Kaskutas Vicki , Sherman‐Voellinger Roslyn , Evanoff Bradley 
Published: November 2007

AbstractBackgroundFalls remain a serious source of morbidity and mortality in residential construction despite considerable knowledge of risk factors and prevention strategies. While training is universally viewed as positive, we know little about its effectiveness in preventing residential falls.MethodsA series of focus groups were conducted with union apprentice carpenters (n = 36) at varied levels of training to elicit input on factors that might influence the effectiveness of residential fall prevention training, including hazard awareness, timing of elements of formal instruction, jobsite mentoring, and workplace norms.ResultsWhile apprentices identified many residential fall hazards, they voiced little concern about work near unprotected vertical or horizontal openings such as stairwells, window openings or leading edges. On residential jobs, apprentices worked at heights immediately and were often exposed to hazards they had not yet been trained to handle. The quality of mentoring varied tremendously, and things they had been taught in school were often not the norm on these small worksites. Use of fall arrest equipment was uncommon. Job insecurity in this fast‐paced work environment influenced behaviors even when apprentices reported knowledge of safe procedures; this was more of a problem for less experienced apprentices.ConclusionsThese data provide compelling evidence that apprentices often do not apply safety principles they have been taught in school in the actual work environment, illuminating how attempts to empower workers through training alone can fall short. The findings have policy implications and demonstrate the importance of measuring more than knowledge when evaluating effectiveness of training. Am. J. Ind. Med. 51:60–68, 2008. © 2007 Wiley‐Liss, Inc.
Perfluorosulfonic ionomer solution in N,N‐dimethylformamide
Authors: Luan Yinghao , Zhang Yongming , Li Lei , Zhang Heng , Zhang Qing , Huang Zhongxi , Liu Yangang 
Published: November 2007

AbstractThe morphology of perfluorosulfonic ionomer molecules in N,N‐dimethylformamide was investigated at different concentrations. Rheological, dynamic light scattering (DLS), and scanning electron microscopy (SEM) measurements were performed on the prepared perfluorosulfonic ionomer solutions or films. The ionomer molecules shrank from rodlike granules to spherelike ones at relatively low concentrations, and the spherelike granules aggregated together to form aggregates at higher concentrations, with capillary liquid bridge force as the driving force. As the solvent evaporated slowly at room temperature, the SEM image showed that the film was loosely stacked by granules and that aggregates formed in the solution. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Preparation of single poly(lactic acid) composites
Authors: Li Ruihua , Yao Donggang 
Published: November 2007

AbstractAn approach for making poly(lactic acid) (PLA) single‐polymer composites (SPCs) on the basis of PLA's slowly crystallizing characteristics was investigated. As a slowly crystallizing polymer, PLA can be processed with standard polymer processing techniques into end‐use products with varied crystallinities, from amorphous films to highly crystalline fibers. In this study, amorphous PLA sheets and crystalline PLA fibers/fabrics were laminated and compression‐molded to form an SPC at a processing temperature substantially lower than PLA's melting temperature. The effects of the major process conditions on the performance of the SPC were studied. The processing temperature played a profound role in affecting the fiber–matrix bonding properties. As the processing temperature increased, a drastic improvement in the interfacial bonding occurred at a temperature of around 135°C, which indicated the lower boundary of the process window. The compression‐molded SPC exhibited enhanced mechanical properties; particularly, the tearing strength of the fabric‐reinforced SPC was almost an order higher than that of the nonreinforced PLA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
A Series of Isolable Silanoic Thio‐, Seleno‐, and Telluroesters (LSi(X)OR) with Donor‐Supported SiX Double Bonds (L=β‐Diketiminate; X=S, Se, Te)
Authors: Yao Shenglai , Xiong Yun , Brym Markus , Driess Matthias 
Published: November 2007

AbstractThe first silicon analogues of carbonic (carboxylic) esters, the silanoic thio‐, seleno‐, and tellurosilylesters 3 (SiS), 4 (SiSe), and 5 (SiTe), were prepared and isolated in crystalline form in high yield. These thermally robust compounds are easily accessible by direct reaction of the stable siloxysilylene L(Si:)OSi(H)L′ 2 (L=HC(CMe)2[N(aryl)2], L′=CH[(CCH2)‐CMe][N(aryl)]2; aryl=2,6‐iPr2C6H3) with the respective elemental chalcogen. The novel compounds were fully characterized by methods including multinuclear NMR spectroscopy and single‐crystal X‐ray diffraction analysis. Owing to intramolecular N→Si donor–acceptor support of the SiX moieties (X=S, Se, Te), these compounds have a classical valence‐bond N+–Si–X− resonance betaine structure. At the same time, they also display a relatively strong nonclassical SiX π‐bonding interaction between the chalcogen lone‐pair electrons (nπ donor orbitals) and two antibonding SiN orbitals (σ*π acceptor orbitals mainly located at silicon), which was shown by IR and UV/Vis spectroscopy. Accordingly, the SiX bonds in the chalcogenoesters are 7.4 (3), 6.7 (4), and 6.9 % (5) shorter than the corresponding SiX single bonds and, thus, only a little longer than those in electronically less disturbed SiX systems (“heavier” ketones).
Silylmetalation of Alkenes
Authors: Nakamura Shinji , Yonehara Mitsuhiro , Uchiyama Masanobu 
Published: November 2007

AbstractSilylmetalation of alkenes is challenging due to the low reactivity of the substrates. In contrast, carbometalation of alkenes has been realized through several innovative methods, including activation of the reagent and the substrate. A similar approach could be applicable to silylmetalation of alkenes, and we have recently developed a bimetal activation method using zincate complexes for this purpose. Here, we describe how the silylzincation of alkenes was achieved. First, the strategies for carbometalation of alkenes will be summarized. Secondly, the history and development of silylzincation chemistry are briefly described. Then the details of our findings related to two types of silylzincation of alkenes, as well as recent progress in mechanistic studies, are discussed. The key point in the silylzincation of alkenes proved to be the bimetal activation of the substrate. One metal (copper or titanium) strongly coordinates and activates the alkene moiety, and the other metal (zinc) acts as the electron acceptor from the silyl group by way of the alkene moiety. This dual activation concept is expected to be applicable to other combinations of metals, as well as to new types of reactions.
Rhodium‐Complex‐Catalyzed Asymmetric Hydrogenation: Transformation of Precatalysts into Active Species
Authors: Preetz Angelika , Drexler Hans‐Joachim , Fischer Christian , Dai Zhenya , Börner Armin , Baumann Wolfgang , Spannenberg Anke , Thede Richard , Heller Detlef 
Published: November 2007

AbstractThe use of diolefin‐containing rhodium precatalysts leads to induction periods in asymmetric hydrogenation of prochiral olefins. Consequently, the reaction rate increases in the beginning. The induction period is caused by the fact that some of the catalyst is blocked by the diolefin and thus not available for hydrogenation of the prochiral olefin. Therefore, the maximum reaction rate cannot be reached initially. Due to the relatively slow hydrogenation of cyclooctadiene (cod) the share of active catalysts increases at first, and this leads to typical induction periods. The aim of this work is to quantify the hydrogenation of the diolefins cyclooctadiene (cod) and norborna‐2,5‐diene (nbd) for cationic complexes of the type [Rh(ligand)(diolefin)]BF4 for the ligands Binap (1,1′‐binaphthalene‐2,2′‐diylbis(phenylphosphine)), Me‐Duphos (1,2‐bis(2,5‐dimethylphospholano)benzene, and Catasium in the solvents methanol, THF, and propylene carbonate. Furthermore, an approach is presented to determine the desired rate constant and the resulting respective pre‐hydrogenation time from stoichiometric hydrogenations of the diolefin complexes via UV/Vis spectroscopy. This method is especially useful for very slow diolefin hydrogenations (e.g., cod hydrogenation with the ligands Me‐Duphos, Et‐Duphos (1,2‐bis(2,5‐diethylphospholano)benzene), and dppe (1,2‐bis(diphenylphosphino)ethane).
Assessable Consequences of Through‐Bond Donor–Acceptor Interactions in β‐Aminoketones
Authors: Lampkins Andrew J. , Li Yan , Al Abbas Alexandre , Abboud Khalil A. , Ghiviriga Ion , Castellano Ronald K. 
Published: November 2007

AbstractReported are the syntheses of ester‐functionalized (6–8) and alkyl‐substituted (9) 1‐aza‐adamantanones; the easy handling of the compounds provides an opportunity to comprehensively study the fundamental changes in structure and reactivity that can accompany the donor–acceptor arrangement in rigid β‐aminoketones. X‐ray structural analysis of trione 6 and dione 7 reveals bond length and angle variations consistent with through‐bond (hyperconjugative) donor–acceptor interactions. Observed is a shortening of the CN bond, elongation of the central CC bond (to ≈1.6 Å), and a significant pyramidalization of the carbonyl carbon within the donor–σ‐acceptor pathway. UV/Vis spectra of 6–9 show a new absorption maximum (λmax=260–275 nm in three solvents), the so‐called “σ‐coupled transition”; the molar absorptivity scales with the number of carbonyl groups (for trione 6, ε ≈3000, for dione 7, ε ≈2000) and the band reversibly disappears upon addition of acid. IR and 13C NMR spectroscopic data show trends consistent with through‐bond donation to the carbonyl acceptor groups and commensurate weakening of the carbonyl π bond. High yielding acid‐mediated fragmentations are used to illustrate the effects of the donor–acceptor arrangement on the reactivity of the molecules. Given that donor–σ‐acceptor molecules have recently been found to show self‐assembly behavior and macromolecular properties linked to their unusual structure, the current analysis encourages further consideration of the systems in advanced materials applications.
Coordination‐Driven Self‐Assembly, Structures, and Dynamic Properties of Diplatinum Hexatriynediyl and Butadiynediyl Complexes in which the sp Carbon Chains are Shielded by sp3 Carbon Chains: Towards Endgroup–Endgroup Interactions
Authors: Owen Gareth R. , Stahl Jürgen , Hampel Frank , Gladysz John A. 
Published: November 2007

AbstractSequential reactions of trans‐(C6F5)(p‐tol3P)2Pt(CC)3SiEt3 (PtC6SiEt3) with nBu4N+ F− (THF/methanol), PtCl, KPF6/tBuOK, and CuCl give trans,trans‐[(C6F5){(p‐tol3P)2}Pt(CC)3Pt{(Pp‐tol3)2}(C6F5)] (PtC6Pt) in 95 % yield on multigram scales. Reactions of PtC6Pt and Ar2P(CH2)mPAr2 afford substitution products trans,trans‐[(C6F5){(Ar2P(CH2)mPAr2)}Pt(CC)3Pt{(Ar2P(CH2)mPAr2)}(C6F5)] (PtC6Pt‐m/Ar; m/Ar=8/p‐tol, 78 %; 10/Ph, 82 %; 11/Ph, 69 %; 12/Ph, 57 %; 14/p‐tol, 57 %; 14/p‐C6H4‐tBu, 71 %), in which the diphosphines span the square planar platinum endgroups. An analogous reaction with PEt3 gives a tetrakis PEt3 complex Pt′C6Pt′ (72 %). The crystal structures of PtC6Pt, Pt′C6Pt′, PtC6Pt‐10/Ph, PtC6Pt‐11/Ph, and PtC6Pt‐14/p‐tol or solvates thereof are compared. In PtC6Pt, the endgroups can avoid van der Waals contact, and define angles of 0°. In PtC6Pt‐14/p‐tol, the sp3 chains twist around the sp chain in a chiral double‐helical motif, with an endgroup/endgroup angle of 189°. The sp3 chains are too short to adopt analogous conformations in the other complexes, but laterally shield the sp chain. NMR spectroscopy shows that the helical enantiomers of PtC6Pt‐14/p‐tol rapidly interconvert in solution at low temperature. A crystal structure of PtC4Pt shows endgroups that are in van der Waals contact and define an angle of 41°. Reactions with Ar2P(CH2)8PAr2 give PtC4Pt‐8/Ar (Ar=Ph, 53 %; p‐tol, 87 %). Low‐temperature NMR spectroscopy establish non‐helical chiral conformations. Electrochemical oxidations of the diplatinum complexes are analyzed, the reversibilities of which decrease with increasing sp chain length.
Synthesis, Self‐Assembling Properties, and Atom Transfer Radical Polymerization of an Alkylated L‐Phenylalanine‐Derived Monomeric Organogel from Silica: A New Approach To Prepare Packing Materials for High‐Performance Liquid Chromatography
Authors: Rahman M. Mizanur , Czaun Miklós , Takafuji Makoto , Ihara Hirotaka 
Published: November 2007

AbstractThe monomer N′‐octadecyl‐Nα‐(4‐vinyl)‐benzoyl‐L‐phenylalanineamide (4) based on L‐phenylalanine has been simply but effectively synthesized, and its self‐assembling properties have been investigated. FTIR and a variable‐temperature 1H NMR spectroscopic investigation demonstrated that the aggregation of compound 4 in various organic solvents is due to the formation of intermolecular hydrogen bonds among the amide moieties. UV/Vis measurements indicated that the multiple π–π interactions of the phenyl groups also contribute to the self‐assembly. As was observed by 13C cross‐polarization magic‐angle spinning (CP/MAS) NMR and variable‐temperature 1H NMR measurements, the ordered alkyl chains also played an important role in the molecular aggregation by van der Waals interactions. Compound 4 was polymerized by surface‐initiated atom transfer radical polymerization from porous silica gel to prepare a packing material for HPLC. The results of thermogravimetric analysis showed that a relatively large amount of polymer was grafted onto the silica surface. The organic phase on silica was in a noncrystalline solid form in which the long alkyl chain exists in a less‐ordered gauche conformation. Analysis of chromatographic performance for polyaromatic hydrocarbon samples showed higher selectivity than conventional reversed‐phase HPLC packing materials.
Fast Lithium Ion Conduction in Garnet‐Type Li7La3Zr2O12.
Authors: Murugan Ramaswamy , Thangadurai Venkataraman , Weppner Werner 
Published: November 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
New Monoterpenoids from Dracocephalum forrestii Aerial Parts.
Authors: Li Gan‐Peng , Zhao Jing‐Feng , Yang Li‐Juan , Yang Xiao‐Dong , Li Liang 
Published: November 2007

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.
Polypharmacy akathisia and associated suicide attempts
Authors: Popli Anand , Gupta Sanjay 
Published: November 2007

AbstractWe report a case of a 72‐year‐old gentleman who developed severe akathisia while on fluoxetine and neuroleptics in a setting of benzodiazepine withdrawal which was associated with a first‐time violent suicide attempt. Depression 1:53–55 (1993) © 1993 Wiley‐Liss, Inc.
The corticotropin releasing factor stimulation test in patients with major depression: Relationship to dexamethasone suppression test results
Authors: Krishnan K. Ranga R. , Rayasam Krishnaiah , Reed Deborah , Smith Mark , Chapell Phillip , Saunders William B. , Ritchie James C. , Carroll Bernard J. , Nemeroff Charles B. 
Published: November 2007

AbstractDepressed patients have been reported to exhibit both a blunted ACTH response to corticotropin‐releasing factor (CRF) and abnormal suppression of plasma cortisol following the administration of dexamethasone. The purpose of the study was to determine the relationship between these two abnormalities. Twenty‐three depressed patients and eighteen control subjects received both a standard CRF stimulation test and the dexamethasone suppression test (DST). Nonsuppressors on the DST exhibited a blunted ACTH response to CRF; DST suppressors exhibited a normal ACTH response to CRF. This suggests that the two abnormalities of the hypothalamic‐pituitary‐adrenal (HPA) axis are related and may be due to similar pathopbysiological mechanisms. Depression 1:133–136 (1993). © 1993 Wiley‐Liss, Inc.
Patient identity in major depression
Authors: Gara Michael A. , Rosenberg Seymour , Woolfolk Robert L. 
Published: November 2007

AbstractThe purpose of this study was to determine whether a strong identification with the patient role at the beginning of treatment was prognostic of depressed symptoms and global level of functioning 9 months later. Subjects were 22 women and 14 men diagnosed with major depression using DSM‐III‐R criteria. Subjects described various identities and people, including “self as patient,” using a free‐response format. A clustering analysis of the free‐response descriptions was used to represent the degree of elaboration of descriptions of the “patient self” relative to descriptions of other identities and people. Subjects also completed several symptom scales (e.g., Beck Depression Inventory) and cognitive measures at the beginning of treatment and then again 9 months later. Greater negative elaboration of the patient identity predicted poorer outcome 9 months later, in terms of both self‐reported depression and level offunctioning. Hierarchical regressions showed that these results were not accounted for by measures of symptoms, functioning, personality, or cognition taken at the beginning oftreatment. Identities other than the “patient” identity did not predict outcome at follow‐up. A strong identification with the patient role appears to be associated with relatively slow recovery from clinical depression. Depression 1:257–262 (1993). © 1993 Wiley‐Liss, Inc.