bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and characterization of aluminum(III) and tin(II) complexes supported by diiminophosphinate ligands and their application in ring‐opening polymerization catalysis of ε‐caprolactone
Authors: Qi Chun‐Yan , Wang Zhong‐Xia 
Published: June 2006

AbstractA series of Al(III) and Sn(II) diiminophosphinate complexes have been synthesized. Reaction of Ph(ArCH2)P(NBut)NHBut (Ar = Ph, 3; Ar = 8‐quinolyl, 4) with AlR3 (R = Me, Et) gave aluminum complexes [R2Al{(NBut)2P(Ph)(CH2Ar)}] (R = Me, Ar = Ph, 5; R = Me, Ar = 8‐quinolyl, 6; R = Et, Ar = Ph, 7; R = Et, Ar = quinolyl, 8). Lithiated 3 and 4 were treated with SnCl2 to afford tin(II) complexes [ClSn{(NBut)2P(Ph)(CH2Ar)}] (Ar = Ph, 9; Ar = 8‐quinolyl, 10). Complex 9 was converted to [(Me3Si)2NSn{(NBut)2P(Ph)(CH2Ph)}] (11) by treatment with LiN(SiMe3)2. Complex 11 was also obtained by reaction of 3 with [Sn{N(SiMe3)2}2]. Complex 9 reacted with [LiOC6H4But‐4] to yield [4‐ButC6H4OSn{(NBut)2P(Ph)(CH2Ph)}] (12). Compounds 3–12 were characterized by NMR spectroscopy and elemental analysis. The structures of complexes 6, 10, and 11 were further characterized by single crystal X‐ray diffraction techniques. The catalytic activity of complexes 5–8, 11, and 12 toward the ring‐opening polymerization of ε‐caprolactone (CL) was studied. In the presence of BzOH, the complexes catalyzed the ring‐opening polymerization of ε‐CL in the activity order of 5 > 7 ≈ 8 > 6 ≫ 11 > 12, giving polymers with narrow molecular weight distributions. The kinetic studies showed a first‐order dependency on the monomer concentration in each case. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4621–4631, 2006
Synthesis of silicon nitride based ceramic nanoparticles by the pyrolysis of silazane block copolymer micelles
Authors: Matsumoto Kozo , Nakashita Junichi , Matsuoka Hideki 
Published: June 2006

AbstractDiblock copolymer poly(1,1,3,N,N′‐pentamethyl‐3‐vinylcyclodisilazane)‐block‐polystyrene (polyVSA‐b‐polySt) and triblock copolymer poly(1,1,3,N,N′‐pentamethyl‐3‐vinylcyclodisilazane)‐block‐polystyrene‐block‐poly(1,1,3,N,N′‐pentamethyl‐3‐vinylcyclodisilazane) (polyVSA‐b‐polySt‐b‐polyVSA), consisting of silazane and nonsilazane segments, were prepared by the living anionic polymerization of 1,1,3,N,N′‐pentamethyl‐3‐vinylcyclodisilazane and styrene. PolyVSA‐b‐polySt formed micelles having a poly(1,1,3,N,N′‐pentamethyl‐3‐vinylcyclodisilazane) (polyVSA) core in N,N‐dimethylformamide, whereas polyVSA‐b‐polySt and polyVSA‐b‐polySt‐b‐polyVSA formed micelles having a polyVSA shell in n‐heptane. The micelles with a polyVSA core were core‐crosslinked by UV irradiation in the presence of diethoxyacetophenone as a photosensitizer, and the micelles with a polyVSA shell were shell‐crosslinked by UV irradiation in the presence of diethoxyacetophenone and 1,6‐hexanedithiol. These crosslinked micelles were pyrolyzed at 600 °C in N2 to give spherical ceramic particles. The pyrolysis process was examined by thermogravimetry and thermogravimetry/mass spectrometry. The morphologies of the particles were analyzed by atomic force microscopy and transmission electron microscopy. The chemical composition of the pyrolysis products was analyzed by X‐ray fluorescence spectroscopy and Raman scattering spectroscopy. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4696–4707, 2006
Preparation and characterization of rigid poly(vinyl chloride)/MMT nanocomposites. II. XRD, morphological and mechanical characteristics
Authors: Chen Cheng‐Ho , Teng Chih‐Chun , Tsai Ming‐Shyong , Yen Fu‐Su 
Published: June 2006

AbstractA Haake torque rheometer equipped with an internal mixer is used to study the influence of the amount of sodium montmorillonite (Na+‐MMT) and organically modified MMT (O‐MMT) on X‐ray diffraction (XRD), morphology, and mechanical characteristics of rigid poly (vinyl chloride) (PVC)/Na+‐MMT and PVC/O‐MMT nanocomposites, respectively. Results of XRD and transmission electron microscopy (TEM) indicate that MMT is partially encapsulated and intercalated in the rigid PVC/Na+‐MMT nanocomposites. However, results of XRD and TEM show MMT is partially intercalated and exfoliated in the rigid PVC/O‐MMT nanocomposites. Tensile strength, yield strength, and elongation at break of the rigid PVC/MMT nanocomposites were improved simultaneously with adding 1–3 wt % Na+‐MMT or O‐MMT with respect to that of pristine PVC. However, the addition of Na+‐MMT or O‐MMT should be kept as not more than 3 wt % to optimize the mechanical properties and the processing stability of the rigid PVC/MMT nanocomposites. SEM micrographs of the fractured surfaces of the rigid PVC/Na+‐MMT and PVC/O‐MMT nanocomposites both before and after tensile tests were also illustrated and compared. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 2145–2154, 2006
Transition state of a SH3 domain detected with principle component analysis and a charge‐neutralized all‐atom protein model
Authors: Mitomo Daisuke , Nakamura Hironori K. , Ikeda Kazuyoshi , Yamagishi Akihiko , Higo Junichi 
Published: June 2006

AbstractThe src SH3 domain has been known to be a two‐state folder near room temperature. However, in a previous study with an all‐atom model simulation near room temperature, the transition state of this protein was not successfully detected on a free‐energy profile using two axes: the radius of gyration (Rg) and native contact reproduction ratio (Q value). In this study, we focused on an atom packing effect to characterize the transition state and tried another analysis to detect it. To explore the atom packing effect more efficiently, we introduced a charge‐neutralized all‐atom model, where all of the atoms in the protein and water molecules were treated explicitly, but their partial atomic charges were set to zero. Ten molecular dynamics simulations were performed starting from the native structure at 300 K, where the simulation length of each run was 90 ns, and the protein unfolded in all runs. The integrated trajectories (10 × 90 = 900 ns) were analyzed by a principal component analysis (PCA) and showed a clear free‐energy barrier between folded‐ and unfolded‐state conformational clusters in a conformational space generated by PCA. There were segments that largely deformed when the conformation passed through the free‐energy barrier. These segments correlated well with the structural core regions characterized by large ϕ‐values, and the atom‐packing changes correlated with the conformational deformations. Interestingly, using the same simulation data, no significant barrier was found in a free‐energy profile using the Rg and Q values for the coordinate axes. These results suggest that the atom packing effect may be one of the most important determinants of the transition state. Proteins 2006. © 2006 Wiley‐Liss, Inc.
Conformational and vibrational study of di‐n‐butyl and di‐sec‐butylphosphonates by MM/QM method
Authors: Carauta Alexandre N. M. , De M. Carneiro José Walkimar , Soto Claudio A. Téllez 
Published: June 2006

AbstractA conformational search by MM/QM method was undertaken for the di‐n‐butyl and di‐sec‐butylphosphonates. The normal mode frequencies and the corresponding vibrational assignments were examined by three theoretical methodologies: AM1, HF/6‐31G*, and B3LYP/6‐31G*. These results were compared with those obtained from the experimental spectra. It was possible to arrive at an accurate spectral assignment, including the region between 1200 and 850 cm−1, which is the most difficult region for spectral assignment. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Hydrogen bonds between hydrogen fluoride and aromatic azines: An ab initio study
Authors: Rusu Victor H. , Ramos Mozart N. , Da Silva João Bosco P. 
Published: June 2006

AbstractMP2/6‐31++G(d,p) ab initio molecular orbital calculations have been employed to characterize hydrogen‐bonded complexes between hydrogen fluoride as proton donor and aromatic azines (pyridine, pyrimidine, pyridazine, pyrazine, 1,3,5‐triazine, and 1,2,4‐triazine). Our calculations have shown that the H‐bond strength in these complexes depends on both the number of nitrogen atoms as well as the position of these atoms in aromatic ring. The binding energies of azines‐HF with or without BSSE and ZPE corrections decrease with the increasing number of nitrogen atoms in the ring. For example, its ΔEBSSE,ZPE value is 40.9 kJ · mol−1 in pyridine‐HF, whereas its corresponding values in pyrazine‐HF and 1,3,5‐triazine‐HF are 34.0 kJ · mol−1 and 26.6 kJ · mol−1, respectively. With respect to position of the nitrogen atom in the aromatic ring, the more pronounced effect is verified when it is at meta‐position relative to the pyridine ring. There is a high linear correlation between the H‐bond strength in these complexes and the intermolecular charge transfer using corrected Mulliken charges obtained from the charge‐charge flux‐overlap (CCFO) modified model for infrared intensities. Finally, our MP2/6‐31++G(d,p) calculations have revealed that stronger hydrogen bonds are associated with smaller H‐bond length values, larger intermolecular charge transfers and greater HF downward stretching frequency displacements. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
An unexpected ion‐molecule adduct in negative‐ion collision‐induced decomposition ion‐trap mass spectra of halogenated benzoic acids
Authors: Attygalle Athula B. , Kharbatia Najeh , Bialecki Jason , Ruzicka Josef , Svatoš Aleš , Stauber Einar J. 
Published: June 2006

AbstractThe ion observed at m/z 145 when product ion spectra of iodobenzoate anions are recorded using ion‐trap mass spectrometers corresponds to the adduct ion [I(H2O)]−. The elements of water required for the formation of this adduct do not originate from the precursor ion but from traces of moisture present in the helium buffer gas. A collision‐induced decomposition (CID) spectrum recorded from the [M–H]− ion (m/z 251) derived from 3‐iodo[2,4,5,6‐2H4]benzoic acid also showed an ion at m/z 145. This observation confirmed that the m/z 145 is not a product ion resulting from a direct neutral loss from the carboxylate anion. 79Bromobenzoate anions produce similar results showing an ion at m/z 97 for [79Br(H2O)]−. The ion‐molecule reaction observed here is unique to ion‐trap mass spectrometers since a corresponding ion was not observed under our experimental conditions in spectra recorded with in‐space tandem mass spectrometers such as triple quadrupole or quadrupole time‐of‐flight instruments. Copyright © 2006 John Wiley & Sons, Ltd.
Mass spectrometric identification and characterization of a new long‐term metabolite of metandienone in human urine
Authors: Schänzer Wilhelm , Geyer Hans , Fußhöller Gregor , Halatcheva Natalia , Kohler Maxie , Parr Maria‐Kristina , Guddat Sven , Thomas Andreas , Thevis Mario 
Published: June 2006

AbstractAnabolic‐androgenic steroids are some of the most frequently detected drugs in amateur and professional sports. Doping control laboratories have developed numerous assays enabling the determination of administered drugs and/or their metabolic products that allow retrospectives with respect to pharmacokinetics and excretion profiles of steroids and their metabolites. A new metabolite generated from metandienone has been identified as 18‐nor‐17β‐hydroxymethyl,17α‐methyl‐androst‐1,4,13‐trien‐3‐one in excretion study urine samples providing a valuable tool for the long‐term detection of metandienone abuse by athletes in sports drug testing. The metabolite was characterized using gas chromatography/(tandem) mass spectrometry, liquid chromatography/tandem mass spectrometry and liquid chromatography/high‐resolution/high‐accuracy (tandem) mass spectrometry by characteristic fragmentation patterns representing the intact 3‐keto‐1,4‐diene structure in combination with typical product ions substantiating the proposed C/D‐ring structure of the steroid metabolite. In addition, structure confirmation was obtained by the analysis of excretion study urine specimens obtained after administration of 17‐CD3‐labeled metandienone providing the deuterated analogue to the newly identified metabolite. 18‐Nor‐17β‐hydroxymethyl,17α‐methyl‐androst‐1,4,13‐trien‐3‐one was determined in metandienone administration study urine specimens up to 19 days after application of a single dose of 5 mg, hence providing an extended detection period compared with commonly employed strategies. Copyright © 2006 John Wiley & Sons, Ltd.
Chemistry of Ru(& 6‐1,3,5‐cyclooctatriene)(η2‐dimethyl fumarate)2
Authors: Mitsudo Take‐Aki , Ura Yasuyuki , Kondo Teruyuki 
Published: June 2006

AbstractThe chemistry of a novel zerovalent Ru complex, Ru(η6‐cot)(η2‐dmfm)2 (1) (cot=1,3,5‐cyclooctatriene; dmfm=dimethyl fumarate), is reviewed with a focus on its reactivity toward phosphines, amines, and H2O, as well as arenes and p‐quinones. A variety of novel zerovalent Ru complexes were synthesized from Ru(η6‐cot)(η2‐dmfm)2 (1), and it was shown that the complexes preferably bear both electron‐donating and ‐accepting ligands simultaneously to exhibit thermodynamic stability. The first isolable zerovalent Ru aqua complexes were successfully prepared, and in these complexes, the generation of a chiral center on the O atom of the coordinated H2O was disclosed. In addition, the characteristic catalytic activity of 1 in organic synthesis was considered by reviewing recently developed novel reactions: (i) dimerization of 2,5‐norbornadiene to pentacyclo[6.6.0.02,6.03,13.010,14]tetradeca‐4,11‐diene (PCTD), (ii) intramolecular hydroamination of aminoalkynes to cyclic imines, (iii) formal [4+2] cycloaddition of alkynes with dmfm to trans‐4‐cyclohexene‐1,2‐dicarboxylates, and (iv) co‐dimerization of dihydrofurans with α,β‐unsaturated esters to 2‐alkylidenetetrahydrofurans. The products obtained here are expected to be used as novel functional organic monomers. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 107–116; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20076
Bridging Uncharted Waters in Georgia: Down Syndrome Association of Atlanta Outreach to Latino/a Families
Authors: Martorell Susan J. , Martorell Gabriela A. 
Published: June 2006

AbstractReceiving the news that your newborn child has Down syndrome is difficult for most parents; difficulties which are compounded by language and cultural barriers for immigrant Latino/a families. The metro Atlanta area has shown a large increase in this population in the last 10 years, and increasing numbers of Latino/a parents with children with Down syndrome are coming in contact with the health care system. Experiences and observations regarding the formation of a Latino/a support group for parents of children with Down syndrome in Atlanta are described. In addition, efforts to integrate these Latino/a parents into a parent education conference sponsored by the Down Syndrome Association of Atlanta are also recounted. Finally, reflections upon the lessons learned and individual and organizational changes that occurred as a result of the process are discussed.
Accuracy of Healthcare Worker Recall and Medical Record Review for Identifying Infectious Exposures to Hospitalized Patients
Authors: Aquino M. , Raboud J. M. , McGeer A. , Green K. , Chow R. , Dimoulas P. , Loeb M. , Scales D. 
Published: June 2006

Objective.To determine the validity of using healthcare worker (HCW) recall of patient interactions and medical record review for contact tracing in a critical care setting.Design.Trained observers recorded the interactions of nurses, respiratory therapists, and service assistants with study patients in a medical-surgical intensive care unit. These observers' records were used as the reference standard to test the criterion validity of using HCW recall data or medical record review data to identify exposure characteristics. We assessed the effects of previous quarantine of the HCW (because of possible exposure) and the availability of patients' medical records for use as memory aids on the accuracy of HCW recall.Setting.A 10-bed medical-surgical intensive care unit at Mount Sinai Hospital in Toronto, Ontario.Patients.Thirty-six HCWs observed caring for 16 patients, for a total of 55 healthcare worker shifts.Results.Recall accuracy was better among HCWs who were provided with patient medical records as memory aids (P<.01). However, HCWs tended to overestimate exposures when they used patient medical records as memory aids. For 6 of 26 procedures or care activities, this tendency to overestimate was statistically significant (P<.05). Most HCWs with true exposures were identified by means of this technique, despite the overestimations. Documentation of the activities of the 4 service assistants could not be found in any of the patients' medical records. Similarly, the interactions between 6 (19%) of 32 other patient–HCW pairs were not recorded in patients' medical records.Conclusions.Data collected from follow-up interviews with HCWs in which they are provided with patient medical records as memory aids should be adequate for contact tracing and for determining exposure histories. Neither follow-up interviews nor medical record review alone provide sufficient data for these purposes.
Dissemination of IMP-1 Metallo-β-Lactamase–Producing Acinetobacter Species in a Brazilian Teaching Hospital
Authors: Tognim Maria C. B. , Gales Ana C. , Penteado Andréia P. , Silbert Suzane , Sader Hélio S. 
Published: June 2006

Objective.To evaluate the emergence and dissemination of metallo-β-lactamase (MBL)–producing Acinetobacter species.Design.All carbapenem-resistant Acinetobacter strains (1 strain per patient) collected during the period 1993–2001 were evaluated.Setting.A Brazilian tertiary care teaching hospital (Hospital São Paulo, São Paulo).Methods.Seventy-three strains of carbapenem-resistant Acinetobacter species were recovered from the organism bank of the hospital. All isolates were tested for antimicrobial susceptibility by broth microdilution methods, and the production of MBL was initially assessed by phenotypic tests (MBL Etest strip and a disk approximation test). The MBL enzymes were identified by polymerase chain reaction using primers for blaIMP’, blaVIM’, and blaSPM’ followed by gene sequencing. Genetic similarity among the carbapenem-resistant strains was evaluated by automated ribotyping.Results.Only colistin and ampicillin-sulbactam showed reasonable in vitro activity against carbapenem-resistant isolates (97% and 74% of isolates susceptible, respectively). More than half of the isolates (55%) had a positive MBL phenotypic test result and a positive polymerase chain reaction result for blaIMP_1 The proportion of IMP-1–producing Acinetobacter isolates among carbapenem-resistant strains increased from 0% in the 1993-1997 period to 29% in 1998 and 100% in the 1999-2001 period. No carbapenem-resistant Acinetobacter isolates that harbored blaVIM or blaSPM were detected. Molecular typing results revealed 20 ribogroups among carbapenem-resistant isolates. During the study period of 1994-2001, we identified 2 major ribogroups, 52-1 (MBL-negative and MBL-positive strains) and 60-7 (MBL-positive strains), that had a coefficient of similarity of 0.85 or higher.Conclusions.Our results indicate that IMP-1–producing strains of Acinetobacter emerged in our institution in 1998. Since then, production of this MBL was detected not only in the major ribogroups of carbapenem-resistant Acinetobacter species but also among isolates that belonged to 17 distinct ribogroups, indicating that this important mechanism of antimicrobial resistance was disseminated among distinct clones.
Control ofLegionella pneumophilaContamination in a Respiratory Hydrotherapy System With Sulfurous Spa Water
Authors: Leoni E. , Sacchetti R. , Zanetti F. , Legnani P. P. 
Published: June 2006

Objective.To evaluate the effectiveness of different disinfection treatments in a spa water system contaminated byLegionella pneumophilaand associated with a case ofLegionellapneumonia.Design.During an 18-month period, the spa water was analyzed by taking samples from the well, the recirculation line, and the final distribution devices (nebulizers and nasal irrigators). Various attempts were made to eradicateLegionellaorganisms by chemical and thermal shock. The final protocol consisted of heat shock treatment at 70°C-75°C for 3 hours, 2 nights per week, followed by a lowering of the water temperature to 30°C ± 1°C for use in the plant. In addition, 3 times a week superheated steam (at a pressure of 1 atmosphere) was introduced for 1 hour into the nebulization machines.Setting.A spa at which sulfurous water was used for hydrotherapy by means of aerosol and nasal irrigation.Patient.A 74-year-old woman with legionnaires disease.Results.After the case of infection occurred,L. pneumophilawas isolated from the recirculation line at a concentration of 400,000 cfu/L and from the nebulizers and nasal irrigators at levels ranging from 3,300 to 1,800,000 cfu/L. The colonizing organisms consisted of a mixture ofL. pneumophilaserogroup 1 (12%) and serogroup 5 (88%). The shock treatment with chlorine dioxide and peracetic acid resulted in the eradication ofLegionellaorganisms from the recirculation line but not from the water generated from the final distribution devices. After the restructuring of the plant and the application of thermal shock protocol, an evaluation after 12 months revealed no evidence ofLegionellacontamination.Conclusion.To preventLegionellacolonization, disinfection treatment is effective if associated with carefully selected materials, good circuit design, and good maintenance practices.
Risk Factors for Surgical Site Infection in Children
Authors: Casanova Juan Francisco , Herruzo Rafael , Díez Jesús 
Published: June 2006

Objectives.To assess the appropriateness of using the indices developed by the Study on the Efficacy of Nosocomial Infection Control (SENIC) and the National Nosocomial Infections Surveillance (NNIS) project to determine risk factors for surgical site infection (SSI) in children and, if not appropriate, to explore the factors related to SSI in children so these factors could be used in a risk index for pediatric patients.Design.Cohort study during more than 4 years.Setting.La Paz University Hospital, a national reference center that serves Health Area 5 of Madrid, Spain, which has approximately 500,000 inhabitants.Patients.Convenience sample consisting of the 3,646 children admitted for surgery who had a postsurgical stay of more than 2 days.Results.A model with 8 predictive factors (degree of surgical contamination; duration of surgery; type of surgery; use of a peripheral venous catheter, central venous catheter, or urinary catheter; number of diagnoses; and SSI exposition time) was created. Its relation to the SSI rate was better than that of the SENIC or NNIS indices. Its sensitivity, specificity, and area under the receiver–operating characteristic curve were higher than that of the SENIC index.Conclusions.The model that we created seems to be more adequate for predicting SSI and evaluating pediatric patients' intrinsic risk than the SENIC and NNIS indices.