bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Nucleating Agents on Crystallization and Melting Behavior and Mechanical Properties of Nucleated Syndiotactic Poly(propylene)
Authors: Supaphol Pitt , Charoenphol Paninlada , Junkasem Jirawut
Published: August 2004

Summary: The effects of various nucleating agents [e.g. 1,3:2,4‐dibenzylidene sorbitol (DBS), 1,3:2,4‐di‐p‐methyldibenzilidene sorbitol (MDBS), 1,3:2,4‐di‐m,p‐methylbenzylidene sorbitol (DMDBS), kaolin, talcum, marl, titanium dioxide (TiO2) and silica (SiO2)] on non‐isothermal melt crystallization and the subsequent melting behavior and mechanical properties of nucleated syndiotactic poly(propylene) (sPP) in comparison with those of the neat sample were investigated. Analysis of the non‐isothermal melt‐crystallization exotherms revealed that the ability of these fillers to nucleate sPP could be ranked from the best to the worst as follows: DBS > talcum > MDBS > kaolin > SiO2 > DMDBS > marl > TiO2. The subsequent melting endotherms for most of the sPP compounds exhibited double melting peaks, while that for the marl‐filled sPP exhibited triple melting peaks. Wide‐angle X‐ray diffraction analysis showed that addition of these fillers did not affect the crystal modification of the sPP matrix. Mechanical property measurements revealed that both the tensile strength and the percentage of elongation at yield for the sPP compounds investigated were not much different from those of the neat sPP. After natural weathering for 1 month, the tensile strength at yield for the sPP compounds investigated increased, at the expense of the percentage of elongation at yield, but, after natural weathering for 3 months, both the tensile strength and the percentage of elongation at yield were found to decrease.

Effects of various organic and inorganic nucleating agents on non‐isothermal melt‐crystallization of syndiotactic poly(propylene) (recorded at a cooling rate of 10 °C · min−1).

magnified image

Effects of various organic and inorganic nucleating agents on non‐isothermal melt‐crystallization of syndiotactic poly(propylene) (recorded at a cooling rate of 10 °C · min−1).
Cover Picture: Macromol. Theory Simul. 7/2004
Authors: Amoskov Victor M. , Birshtein Tatiana M. , Darinskii Anatoly A. , Tupitsyna Alla I.
Published: August 2004

Cover: The picture on the cover shows how a lateral force (flow) applied to a polymer brush induces its compression.

Further details can be found in the Full Paper by V. M. Amoskov, T. M. Birshtein,* A. A. Darinskii, and A. I. Tupitsyna on page 629.
Impact of the motor complications of Parkinson's disease on the quality of life
Authors: Chapuis Stéphane , Ouchchane Lemlih , Metz Olivier , Gerbaud Laurent , Durif Franck
Published: August 2004

The impact of motor complications of Parkinson's disease (PD), especially levodopa‐induced dyskinesias, on quality of life (QL) was studied in 143 patients with PD. All were evaluated on the Hoehn and Yahr (H&Y) scale, and the Motor part of the Unified Parkinson's Disease Rating Scale (UPDRS). Motor complications were analyzed using the UPDRS Parts IVA and IVB and the Abnormal Involuntary Movement Scale. A specific Parkinson's disease quality of life questionnaire (39‐item version, PDQ‐39) was used. Motor complications significantly worsened the PDQ‐39 Summary Index (PDQ‐SI) of patients with PD. The dimensions of Mobility, Activities of Daily Living, Stigma, and Communication were the most strongly affected. “Peak dose” dyskinesia decreased Mobility, Emotional Well‐Being, and Cognition, whereas biphasic dyskinesia affected Mobility, Stigma, Communication, and Activities of Daily Living. Morning akinesia, end‐of‐dose fluctuations, and “unpredictable offs” decreased QL on the dimensions of Mobility, Activities of Daily Living, Stigma, and Communication. Nocturnal akinesia led to a deterioration of all dimensions of the PDQ‐39. Thus, motor complications and especially nocturnal akinesia and biphasic dyskinesias worsened the QL of PD patients. © 2004 Movement Disorder Society
Disturbed egocentric space representation in cervical dystonia
Authors: Müller Sandra V. , Gläser Peggy , Tröger Matthias , Dengler Reinhard , Johannes Sönke , Münte Thomas F.
Published: August 2004

In addition to visual spatial input, vestibular and proprioceptive signals are used in judging the egocentric space. We asked whether the abnormal head posture of patients with cervical dystonia (CD) is associated with distortions of their internal spatial reference frame. The perception of subjective straight‐ahead (SSA) was tested under various conditions in 28 CD patients and in matched controls. They were asked to direct a laser pointer to the position that they believed to be “straight ahead” relative to their bodies' orientation (body‐centered spatial perception). Body‐independent visual spatial perception was assessed with different neuropsychological tests. CD patients had a greater deviation of the subjective straight ahead, indicating body‐centered visual spatial perception, than controls. No effects were seen in body‐independent visual spatial perception. Patients with CD are impaired in body‐centered, egocentric spatial perception, but not in body‐independent, allocentric spatial perception. © 2004 Movement Disorder Society
Substituent effects on scalar J(13C, 13C) couplings in pyrimidines. An experimental and DFT study
Authors: de Kowalewski Dora G. , Díez Ernesto , Esteban Angel L. , Barone Verónica , Peralta Juan E. , Contreras Rubén H.
Published: August 2004

One‐ two‐ and three 13C, 13C (n = 1, 2, 3) scalar couplings, nJ(C,C) in a set of pyrimidine derivatives were studied both experimentally at natural abundance and theoretically by their DFT calculation of all four contributions. Trends of non‐contact terms are discussed and substituent effects are rationalized, comparing some of them with the corresponding values in benzene and pyridine. Although substituent effects on non‐contact terms are relatively important, the whole trend is dominated by the Fermi contact term. According to the current literature, substituent effects on 1J(C,C) couplings in benzene derivatives are dominated by the inductive effect, which, apparently, is also the case in nitrogen heteroaromatic compounds. However, some differences observed in this work for substituent effects on 1J(C,C) couplings in pyrimidine derivatives suggest that in the latter type of compounds substituent effects can be affected by the orientation of the ring nitrogen lone pairs. Copyright © 2004 John Wiley & Sons, Ltd.
Dependence of 1H NMR chemical shifts of geminal protons of glycosyloxy methylene (H2‐26) on the orientation of the 27‐methyl group of furostane‐type steroidal saponins
Authors: Agrawal Pawan K.
Published: August 2004

An approach based on the difference (Δab = δa − δb) between the 1H NMR chemical shifts (δa, δb) of the geminal protons of glycosyloxy methylene (H2‐26) (Δab = <0.48 for 25R; Δab = >0.57 for 25S) is proposed for ascertaining 25R/25S orientation of the 27‐methyl group of furostane‐type steroidal saponins. These studies suggested the 25R‐orientation of the 27‐Me group for the furostanol glycosides isolated by Wu et al. from Tribulus terrestris. Copyright © 2004 John Wiley & Sons, Ltd.
A study of the 17O carbonyl chemical shifts in substituted benzaldehydes
Authors: Li Lidong , Li Linsheng
Published: August 2004

An analysis of 17O carbonyl chemical shifts of 50 substituted benzaldehydes leads to an empirical equation, δcal(17O) = 564.0 + ΣΔo + ΣΔm + ΣΔp + C, for calculating 17O chemical shifts. This equation is based on a linear regression analysis using 11 substituent parameters and leads to good conformity with the expected data. Copyright © 2004 John Wiley & Sons, Ltd.
Heating caused by radiofrequency irradiation and sample rotation in 13C magic angle spinning NMR studies of lipid membranes
Authors: Dvinskikh Sergey V. , Castro Vasco , Sandström Dick
Published: August 2004

Application of rapid sample rotation and radiofrequency irradiation in magic angle spinning (MAS) NMR of lipid bilayers can significantly increase the sample temperature. In this work, we studied the extent of heating during the acquisition of 1H‐decoupled 13C MAS spectra of hydrated dimyristoylphosphatidylcholine (DMPC) in the Lα phase. First, we describe a simple procedure for determining the increase in temperature by observing the shift of the 1H water signal. The method is then used to identify and assess the various factors that contribute to the sample heating. The important factors discussed in this paper include: (i) the spinning speed, (ii) the variable‐temperature gas pressure, (iii) the rotor geometry, (iv) the power, duration and frequency of the radiofrequency irradiation and (v) the hydration level. A comparison of different heteronuclear decoupling schemes in terms of their ability to produce highly resolved 13C spectra of DMPC is also reported. Copyright © 2004 John Wiley & Sons, Ltd.
Theoretical studies on the aromaticity of selected hydroxypyrones and their cations and anions. Part 1—Aromaticity of heterocyclic pyran rings
Authors: Zborowski Krzysztof , Grybos Ryszard , Proniewicz Leonrad M.
Published: August 2004

The aromaticity of heterocyclic pyran rings in selected hydroxypyrones and their anions and cations was studied using three aromaticity indices, HOMA, I6 and NICS. These values were determined for theoretical geometries obtained at the HF, SVWN, B3LYP and B1LYP levels of calculations with the 6–311 + +G(d,p) basis set. The data obtained show that the aromaticity for the hydroxypyrones under investigation increases in the order: anion < neutral molecule < cation. Copyright © 2004 John Wiley & Sons, Ltd.
Kinetic isotope effects for non‐adiabatic proton transfer in benzophenone—N‐methylacridan contact radical ion pairs
Authors: Peters Kevin S. , Kim Ganghyeok
Published: August 2004

The dynamics of proton transfer within a variety of substituted benzophenones–N‐methylacridan contact radical ion pairs in benzene were examined. The correlation of the rate constants for proton transfer with the thermodynamic driving force reveals both normal and inverted regions for proton transfer in benzene. Employing the isotopically labeled compounds N‐methyl‐d3‐acridan and N‐methylacridan‐9,9‐d2, the kinetic deuterium isotope effects were examined. The isotope dependence for the transfer process was examined within the context of the Lee–Hynes model for non‐adiabatic proton transfer. The theoretical analysis of the experimental data suggests that the reaction path for proton–deuteron transfer involves tunneling. Conventional transition‐state theory with the inclusion of the Bell correction for tunneling in the region of the transition state cannot account for the observed kinetic behavior. Copyright © 2004 John Wiley & Sons, Ltd.
A new concept for isotope ratio monitoring liquid chromatography/mass spectrometry
Authors: Krummen Michael , Hilkert Andreas W. , Juchelka Dieter , Duhr Alexander , Schlüter Hans‐Jürgen , Pesch Reinhold
Published: August 2004

A new interface for the on‐line coupling of a liquid chromatograph to a stable isotope ratio mass spectrometer has been developed and tested. The interface is usable for 13C/12C determination of organic compounds, allowing measurement of small changes in 13C abundance in individual analyte species. All of the carbon in each analyte is quantitatively converted into CO2 while the analyte is still dissolved in the aqueous liquid phase. This is accomplished by an oxidizing agent such as ammonium peroxodisulfate. The CO2 is separated from the liquid phase and transferred to the mass spectrometer. It is shown that the whole integrated process does not introduce isotope fractionation. The measured carbon isotope ratios are accurate and reproducible. The sensitivity of the complete system allows isotope ratio determination down to 400 ng of compound on‐column. By‐passing the high‐performance liquid chromatography (HPLC) separation allows bulk isotopic analysis with substantially lower sample amounts than those required by conventional elemental analyzers. The results of the first applications to amino acids, carbohydrates, and drugs, eluted from various types of HPLC columns, are presented. The wide range of chromatographic methods enables the analysis of compounds never before amenable to isotope ratio mass spectrometry techniques and may lead to the development of many new assays. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of different scheduling policies on traffic class dependent routing in intersatellite link networks
Authors: Kandus Gorazd , Svigelj Ales , Mohorcic Mihael
Published: August 2004

The provision of multimedia applications characterized by the integrated presentation of various data sources requires a network infrastructure providing broadband access, large available bandwidth in the core network, and traffic differentiation which supports efficient utilization of network resources and service level guarantees. In order to distinguish between different traffic classes and to optimize utilization of network resources to their respective requirements, an efficient routing procedure capable of differentiating traffic and adapting to highly dynamic conditions in a non‐geostationary ISL network needs to be implemented in combination with advanced fair scheduling policies in the outgoing queues. In this paper we analyze the performance of different scheduling policies in conjunction with adaptive routing procedures in the intersatellite link network of a packet‐switched non‐geostationary satellite system. In particular, different unfair (first come first served and priority) and fair (weighted round robin, deficit round robin and surplus round robin) scheduling policies are considered, in combination with single‐service routing and traffic class dependent routing procedures. The performance of different scenarios is assessed, by means of simulation, in terms of average packet delay and average data throughput. The simulation results indicate that differentiated treatment of traffic using traffic class dependent routing and fair scheduling policies provides a significant improvement in overall performance for all traffic classes, regardless of the traffic scenario considered. Copyright © 2004 John Wiley & Sons, Ltd.
The task force on advanced satellite mobile systems: structure, objectives and vision
Authors: Corazza Giovanni E. , King Geoff J.
Published: August 2004

This paper describes the origins of the Advanced Satellite Mobile Systems Task Force (ASMS‐TF), its structure and its membership. The paper also discusses the overall vision of the Task Force for the short and for the long term, and the objectives which the Task Force is pursuing. What the Task Force has achieved so far in its existence is listed, together with its future plans and priorities. Copyright © 2004 John Wiley & Sons, Ltd.
Solvolthermal Syntheses and Crystal Structures of Three Linear Trinuclear Schiff Base Complexes of Zinc(II) and Cadmium(II)
Authors: You Zhong‐Lu , Zhu Hai‐Liang , Liu Wei‐Sheng
Published: August 2004

Three linear trinuclear Schiff base complexes, {Zn[Zn(CH3COO)(C17H16N2O2)]2} (1), {Zn[Zn(CH3COO)(C25H20N2O2)]2} (2), and {Cd[Cd(CH3COO)(C18H18N2O2)]2} (3), were synthesized for the first time under solvolthermal conditions. Their structures have been characterized by elemental analyses, X‐ray single crystal determinations, and infrared spectroscopy. There are three bridges across the M‐M atom pairs (M is Zn for 1 and 2, or Cd for 3) in each complex, involving two O atoms of a Schiff base ligand (N,N′‐bis(salicylidene)‐1, 3‐propanediaminate (SALPD2‐) for 1, N, N′‐bis(2‐hydroxy‐naphthalmethenylimino)‐1, 3‐propanediaminate (NAPTPD2‐) for 2, and N,N′‐bis‐(salicylidene)‐1,4‐butanediaminate (SALBD2‐) for 3), and an O‐C‐O moiety of a μ‐acetato group. In each of the complexes, the central M2+ ion is located on an inversion center and has a distorted octahedral coordination involving four bridging O atoms from two Schiff base ligands in the equatorial plane and one O atom from each bridging acetate group in the axial positions. The coordination around the terminal M2+ ions is irregular square pyramidal, with two O atoms and two N atoms of the Schiff base ligand in the basal plane and one O atom from an acetate group in the apical position. The acetate bridges linking the central and terminal M2+ ions are mutually trans. The M…M distances are 3.050(3) Å in 1, 3.139(2) Å in 2, and 3.287(6) Å in 3.
Two‐dimensional Anhydrous Cadmium(II) Phthalate
Authors: Tang Yun‐Zhi , Qian Shao‐Song , Wang Xi‐Sen , Zhao Hong , Huang Xue‐Feng , Li Yong‐Hua , Jiao Xing‐Cai , Xiong Ren‐Gen
Published: August 2004

The in situ hydrolysis of phthalyl‐γ‐glutaminyl‐histidine with Cd(ClO4)2·6H2O in the presence of water and methanol affords a novel two‐dimensional cadmium coordination polymer, a new phase, anhydrous cadmium(II) phthalate, (1). The structure was determined by single crystal X‐ray diffraction. Crystal data: P21/c, a = 13.8168(14), b = 7.0351(7), c = 8.2054(8) Å, β = 105.540(2)°, V = 768.43(13) Å3, Z = 4, R1 = 0.0380, wR2 = 0.1111.
Novel Heterobimetallic Neodymium/Calcium 8‐Quinolinolate Complexes Prepared Directly From the Metals
Authors: Deacon Glen B. , Junk Peter C. , Leary Stuart G.
Published: August 2004

Reaction of 8‐hydroxyquinoline (HOQ) with calcium and neodymium metal (mole ratio 1.6:0.72:1.1) in the presence of mercury at 110 °C under vacuum in a durene flux yielded bis(8‐quinoli‐nolato‐κ:N, O(Nd))hexakis(μ‐(O)‐8‐quinolinolato‐κ:N(Nd), O(Nd, Ca))calcium(II) dineodymium(III) (NdCaNd) (1) ($P {\bar 1}$, a = 11.305(2), b = 12.468(3), c = 13.918(3) Å, α = 116.62(3), β = 95.46(3), γ = 109.59(3)°, V = 1580.6(6) Å3, R1 = 0.0718). The trimetallic was again obtained but as the solvate 1. (HOQ) from reaction between HOQ, Nd and Ca, (mole ratio 2.8:2:1) in a 1, 3, 5‐tri‐tert‐butylbenzene flux $P {\bar 1}$, a = 10.206(2), b = 12.256(3), c = 13.819(3) Å, α = 85.93(3), β = 89.94(3), γ = 81.36(3)°, V = 1704.5(6) Å3, R1 = 0.0592).
Die Kristallstrukturen der Dicaesium‐Dodekahalogeno‐closo‐Dodekaborate Cs2[B12X12] (X = Cl, Br, I) und ihrer Hydrate
Authors: Tiritiris Ioannis , Schleid Thomas
Published: August 2004

Durch Reaktionen von Cs2[B12H12] mit den entsprechenden elementaren Halogenen (Cl2, Br2 bzw. I2) wurden die perhalogenierten Derivate Cs2[B12X12] (X = Cl ‐ I) erhalten. Beim Umkristallisieren aus wäßriger Lösung fielen dabei zunächst die Dihydrate (Cs2[B12X12] · 2 H2O) in Form von farblosen, polyederförmigen Einkristallen an, die sich unter Erhalt ihrer Kristallinität über die Monohydrate (Cs2[B12X12] · H2O) schließlich topotaktisch zu den wasserfreien Verbindungen (Cs2[B12X12]) dehydratisieren lassen. Mittels Röntgenbeugung an Einkristallen war es möglich, die ionischen Caesium‐Salze strukturell zu charakterisieren. Alle drei Halogenoborate sind isotyp und kristallisieren bei Raumtemperatur trigonal in der Raumgruppe $R {\bar 3}$ (Cs2[B12Cl12]: a = 959, 67(3) pm, c = 4564, 2(2) pm; Cs2[B12Br12]: a = 997, 92(3) pm, c = 4766, 4(3) pm; Cs2[B12I12]: a = 1047, 05(4) pm, c = 5018, 3(3) pm; Z = 6). Der Kristallstruktur liegt eine kubisch dichteste Kugelpackung aus zwei kristallographisch unabhängigen quasi‐ikosaedrischen [B12X12]2‐‐Anionen (Cs2[B12Cl12]: d(B‐B) = 178 ‐ 179 pm, d(B‐Cl) = 179 ‐ 180 pm; Cs2[B12Br12]: d(B‐B) = 176 ‐ 180 pm, d(B‐Br) = 195 ‐ 197 pm; Cs2[B12I12]: d(B‐B) = 177 ‐ 182 pm, d(B‐I) = 214 ‐ 217 pm) zugrunde. Durch geordnete Halbbesetzung der Tetraeder‐ und formale Vollbesetzung der Oktaederlücken einer jeden Zwischenschicht mit Cs+‐Kationen bildet sich eine Struktur aus, in der (Cs1)+ trigonal aplanar (CN = 9) von drei und (Cs2)+ tetraedrisch (CN = 12) von vier [B12X12]2‐‐Anionen umgeben wird. Dabei sind stets Ikosaeder‐Dreiecksflächen aus Halogenatomen koordinativ wirksam. In den prinzipiell isostrukturellen Mono‐ und Dihydraten wird die unvollständige Koordinationssphäre von (Cs1)+ durch ein bzw. zwei Wassermoleküle ergänzt. Mittels DTA/TG‐Untersuchungen im Bereich zwischen Raumtemperatur und 1200 °C konnte der thermische Abbau der Dicaesium‐Dodekahalogeno‐closo‐Dodekaborat‐Hydrate und ihrer Entwässerungsprodukte verfolgt werden. Zusätzlich wurden die Verbindungen auch mittels 11B‐NMR‐Spektroskopie in wäßriger Lösung charakterisiert.
Schwefelverbrückte Kupferkomplexe mit Farbstoffliganden
Authors: Fuhr Olaf , Fenske Dieter
Published: August 2004

In einer dreistufigen Synthese wird der Farbstoff Et2N‐C6H4‐NN‐C6H4‐SSiMe3 (1) (azo‐SSiMe3) hergestellt, der mit Kupfer(I)chlorid unter Me3SiCl‐Abspaltung zu verschiedenen schwefelverbrückten Komplexen reagiert. In Abhängigkeit von der Anwesenheit unterschiedlicher Phosphanliganden werden die Verbindungen [Cu2(S‐azo)2(PEt3)3] (2), [Cu2(S‐azo)2(PnPr3)3] (3) und [Cu3(S‐azo)3(PPh3)4] (4) erhalten. Diese sowie auch der silylierte Farbstoff 1 konnten in einkristalliner Form isoliert und charakterisiert werden (1: Raumgruppe $P {\bar 1}$, a = 769, 2(2) pm, b = 943, 0(2) pm, c = 1419, 4(3) pm, α = 89, 09(3)°, β = 76, 40(3)°, γ = 87, 40(3)°, Z = 2; 2: Raumgruppe P21/c, a = 1142, 3(2) pm, b = 2233, 7(5) pm, c = 2391, 8(5) pm, β = 102, 84(3)°, Z = 4; 3: Raumgruppe P21/c, a = 1076, 0(2) pm, b = 1858, 4(4) pm, c = 3284, 1(7) pm, β = 95, 10(3)°, Z = 4; 4: Raumgruppe $P {\bar 1}$, a = 1353, 9(3) pm, b = 1615, 8(3) pm, c = 29966, 6(3) pm, α = 92, 24(3)°, β = 97, 48(3)°, γ = 98, 83(3)°, Z = 2). Die UV‐VIS‐Spektren von 1‐4 werden dominiert von der starken Absorption durch die Diethyamino‐azobenzol‐Gruppe. Im Vergleich zu 1 zeigen 2 und 3 eine starke, 4 eine etwas schwächere bathochrome Verschiebung des Absorptionsmaximums.
Kristallographische Gruppe‐Untergruppe‐Beziehungen und ihre Anwendung in der Kristallchemie
Authors: Müller Ulrich
Published: August 2004

Stammbäume von kristallographischen Gruppe‐Untergruppe‐Beziehungen eignen sich besonders gut, um Verwandtschaftsbeziehungen zwischen Kristallstrukturtypen aufzuzeigen. Ausgehend von einem Aristotyp, einem einfachen, hochsymmetrischen Strukturtyp, kommt man durch Verringerung der Raumgruppensymmetrie zu immer komplizierteren Varianten. Dabei ist es von Bedeutung, genau zu verfolgen, wie sich die besetzten Punktlagen von Raumgruppe zu Untergruppe entwickeln und welche Koordinatentransformationen und Ursprungsverschiebungen auftreten. Die dazu notwendige Information kann dem neuen Band A1 von International Tables for Crystallography entnommen werden. Anhand von Beispielen werden mögliche Fehlerquellen aufgezeigt. Wenn sich eine Punktlage in mehrere symmetrieunabhängige Punktlagen aufspaltet, sind Substitutionsderivate möglich. Spaltet sie nicht auf, dann muß sich ihre Punktlagensymmetrie verringern, was Verzerrungsvarianten ermöglicht. Solche sind von besonderer Bedeutung bei Phasenumwandlungen, auf die an den Beispielen K2[TeBr6], (NO)2[TiCl6] und SrCu2(BO3)2 eingegangen wird. Bei Phasenumwandlungen unter Symmetrieerniedrigung ist mit dem Auftreten von Mehrlingskristallen zu rechnen. Am Beispiel CaMnF5 wird gezeigt, wie dies zu Fehlern bei Kristallstrukturbestimmungen führen kann. Die Möglichkeiten zur Besetzung von Lücken in Kugelpackungen können systematisch verfolgt und berechnet werden, womit sich auch Kristallstrukturen vorhersagen lassen. Mitunter treten exotisch anmutende Indizes des Symmetrieabbaus auf, wie 13 bei CZr6I12 und 37 bei PtCl3. Molekülpackungen lassen sich ebenfalls systematisch erfassen, zum Beispiel bei den Modifikationen von P4S3. Tetraphenylphosphoniumsalze kristallisieren häufig in der Raumgruppe P4/n oder deren Untergruppen, wobei die pseudotetragonale Symmetrie auch bei monoklinen und triklinen Strukturen erkennbar bleibt.
Viruses adsorbed on musculoskeletal allografts are inactivated by terminal ethylene oxide disinfection
Authors: Moore Tillman M. , Gendler Eli , Gendler El
Published: August 2004

In 1987 it was anticipated that unsterilized tissues would transmit virus diseases such as hepatitis and HIV‐1 from infected donors so a freeze‐drying process for musculoskeletal tissue was developed to include terminal ethylene oxide (EO) exposure for 14 h. We found no studies of EO efficacy when viruses were associated with human allografts so we studied the antiviral effect of terminal EO disinfection using all but the final freeze‐drying phase of this clinical processing protocol (CPP). Specifically we looked at EO inactivation of HIV‐1, a human hepatitis B surrogate and test viruses known to be highly resistant to disinfecting agents, including irradiation. Freeze‐drying, ordinarily required after EO disinfection and part of the CPP, was not done. Suspensions of HIV‐1, Bovine viral diarrhea, Reovirus type 3, Duck hepatitis B, Poliomyelitis and Canine parvovirus were adsorbed on glass, demineralized bone powder, and preprocessed strips of femoral cortex, iliac wedges, cancellous blocks and patellar bone–tendon–bone preparations and subjected to EO disinfection. Test viruses were inactivated at the end of 7 h of EO disinfection, providing a safety factor in the CPP of at least 100%.

Because allografts can transmit viruses, terminal EO disinfection should provide safer musculoskeletal allografts than non‐disinfected tissues or those irradiated with a standard irradiation dose. New spontaneously appearing viruses would probably be inactivated with this terminal EO disinfection but they and viral bioweapons will require individual validation to assure viral inactivation. © 2004 Orthopaedic Research Society. Published y Elsevier Ltd. All rights reserved.
Sagittal bowing of the distal femur in Chinese patients who require total knee arthroplasty
Authors: Tang W. M. , Chiu K. Y. , Kwan M. F. Y. , Ng T. P. , Yau W. P.
Published: August 2004

Purposes: The importance of the femoral sagittal bowing on total knee arthroplasty is under‐recognized. The bowing could lead to potential errors in positioning of the femoral component if it is ignored. We aimed to document the femoral sagittal bowing at different segments of the Chinese femur and to discuss the implications of this sagittal bowing on total knee arthroplasty.

Methods: One hundred lateral radiographs of the entire lower limbs of 85 Chinese patients admitted for total knee arthroplasty were digitized. The radii of curvature of the intramedullary canal of the proximal, middle and distal one‐third of the femora were measured.

Results: The average age of the patients was 67.3 years. The radii of curvature of the proximal, middle and distal one‐third of the femora were 1081.6, 926.2 and 715.1 mm, respectively. The distal one‐third of the femora was significantly more bowed than the other parts of the femora (p < 0.001). The distal femoral bowing was more profound in rheumatoid patients and in those with a short femur.

Conclusions: The lateral contour of the Chinese femur is like a hockey stick. This exaggerated sagittal bowing in the Chinese femur can affect the final sagittal position of the femoral component and has implications for the choice of implant design. In revision setting, a long and straight press‐fit stem might either endanger the anterior cortex or deflect the femoral component to an abnormally extended position. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Spatial organization of types I and II collagen in the canine meniscus
Authors: Kambic Helen E. , McDevitt Cahir A.
Published: August 2004

The meniscus of the knee joint is a fibrocartilage mainly composed of type I collagen and smaller amounts of type II collagen. The distribution of type II collagen in the canine meniscus and its spatial relationship to type I collagen was examined by immunohistochemistry and confocal microscopy.

Dorsal and coronal slices of the mid‐section of medial and lateral menisci from the knee joints of skeletally mature dogs were predigested with Streptomyces hyaluronate lyase and bacterial Protease enzyme XXIV. Monoclonal antibodies against type I collagen (CP17L) and type II collagen (II‐II6B3) and an anti‐type II collagen polyclonal antibody (AB759) were employed.

The staining for type II collagen in the extracellular matrix of hyaline articular cartilage was diffuse without any identifiable spatial organization. In striking contrast, type II collagen in the fibrocartilage of the meniscus stained as an organized network. Type II collagen was distributed throughout the meniscus with the exception of the outer zone containing the blood vessels.

Coronal and dorsal staining of the meniscus showed bundles of circumferential fibrils of type I that colocalized with type II collagen in specific sites. These bundles were enwrapped in a second organizational fibrillar system of types I and II collagen that also colocalized. Bundles of circumferential fibrils appeared in cross‐section in coronal sections as dots within the interstitial spaces framed by the network of types I and II collagen of the second system. Confocal overlays showed that types I and II collagens were superimposed, suggesting a close spatial proximity between the two collagens. The cells were confined to the types I and II collagen fibrils that enwrapped the bundles. A striking feature of the radial tie fibers was patches of type II collagen without colocalized type I collagen.

Our study reveals a unique network of type II collagen in fibrocartilage of the meniscus that serves as a morphological distinction between fibro‐ and hyaline cartilage. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.
Marine boundary layer dust and pollutant transport associated with the passage of a frontal system over eastern Asia
Authors: Bates Timothy S. , Quinn Patricia K. , Coffman Derek J. , Covert David S. , Miller Theresa L. , Johnson James E. , Carmichael Gregory R. , Uno Itsushi , Guazzotti Sergio A. , Sodeman David A. , Prather Kimberly A. , Rivera Monica , Russell Lynn M. , Merrill John T.
Published: August 2004

Aerosol chemical composition and number size distributions were measured aboard the R/V Ronald H. Brown during the Asian Pacific Regional Aerosol Characterization Experiment (ACE‐Asia) from 14 March to 20 April 2001. This manuscript focuses on the prefrontal and postfrontal air masses sampled aboard the ship in the Sea of Japan between 6 and 15 April 2001 to illustrate the different chemical sources/mixtures off the coast of Asia resulting from the contrasting meteorological transport patterns. The prefrontal air masses had a dominant accumulation mode composed of pollution and volcanic aerosols. The aerosol was predominately ammonium sulfate and organic carbon. Minor amounts of dust were present in the marine boundary layer (MBL) as a result of subsidence from a pronounced Taklimakan dust aerosol layer aloft. The sea salt in both the submicron and supermicron modes was highly depleted in chloride from reaction with sulfuric and nitric acid vapors. The passage of a large low‐pressure center, surrounded by a widespread distribution of airborne dust, on 10 April brought elevated concentrations of submicron and supermicron Gobi desert dust to the ship. The supermicron dust particles contained high concentrations of sulfate, nitrate, organic, and elemental carbon. The MBL aerosol properties and controlling processes described here provide data to evaluate and refine chemical transport models.
A graded stream response relation for bed load–dominated streams
Authors: Eaton Brett C. , Church Michael
Published: August 2004

The relation between equilibrium stream channel morphology and three independent governing variables, discharge, sediment supply, and valley slope, is investigated using a stream table. The experiments are based on a generic physical model of a laterally active gravel bed stream and directed by a recently published rational regime model. While a variety of channel adjustments are possible, the primary adjustment observed was in the channel slope. Other adjustments, such as surface armor composition and cross‐sectional shape, were minor in comparison. The equilibrium slope is well predicted by a linear function of sediment concentration which is bounded by two thresholds: one associated with the minimum stream power necessary to deform the bed and the other associated with the maximum sediment feed that can be transported by the available flow. The results suggest that the system tends to move toward the minimum slope capable of transporting the sediment supply, in the process increasing the flow resistance for the system. Whether or not a minimum slope or a maximum system‐scale flow resistance is reached cannot be determined given the available data, but there appears to be a unique slope (or, at least, a limited range of slopes) for which a stable alluvial channel morphology can be established for a given sediment concentration. The implications of this behavior are evaluated for the theoretical basis of the extremal hypothesis used to close the formulation of a rational regime model.
Top of the crystalline basement in the Levant
Authors: Rybakov Michael , Segev Amit
Published: August 2004

A structural map of depth to the top of the crystalline basement has been constructed for the Middle East continental and marine terrains by reviewing available relevant information on the Levant (deep boreholes, seismic profiles, and magnetic and gravity data (and adopting the regional compilation of Cornell University for the adjacent areas. This new compilation enabled significant upgrading of the Cornell University database for the Levant with emphasis on Israel. The present top of the crystalline basement map gives a good large‐ and medium‐scale overview on the basement relief of a complex area that includes (1) the African and Arabian continental platforms; (2) the Mesozoic Levant passive continental margins; (3) the Mesozoic Syrian arc and the Palmyrides fold belt and rifts; (4) the Cenozoic Cyprus collision zone; (5) the Alpine orogenic belt of Turkey; (6) the Red Sea oceanic spreading center and the Suez rift; and (7) the Dead Sea Transform.
Evidence of continuing methylchloroform emissions from the United States
Authors: Millet Dylan B. , Goldstein Allen H.
Published: August 2004

We present measurements from three sites during 2001–2002 showing that methylchloroform emissions have continued in the U.S., despite the 1996 production ban under the Montreal Protocol. Available data from urban regions, if representative, suggest that 1997–2002 U.S. emissions declined exponentially from 18.5 to 3.0 Gg/yr. F‐11 also showed evidence of ongoing emissions, whereas F‐113 emissions have effectively ceased. Continuous in‐situ measurements in urban regions provide an effective means of detecting ongoing emissions of banned compounds. Neglecting continuing emissions causes underestimates in tropospheric OH abundance derived from methylchloroform concentrations.
Seismic properties of layer 2A at 11 Ma: Results of a vertical seismic profile at Ocean Drilling Program Site 1243
Authors: Carlson R. L.
Published: August 2004

A variety of seismic experiments indicate that seismic velocities in the uppermost oceanic crust (layer 2A) increase very rapidly with age, nearly doubling in 10 my or less, but only one measurement was made in situ, by an oblique seismic experiment in DSDP/ODP Hole 504B. A VSP acquired in 11 Ma crust at ODP Site 1243 yields a velocity of 4.21 ± 0.08 km s−1, which is consistent with previous observations. The absence of a vertical velocity gradient at Site 1243 is consistent with the hypothesis that layer 2A is modified by a process of progressive sealing of cracks from the bottom up. Application of an asperity deformation model suggests that the area of contact across cracks in layer 2A increases by a factor of ∼100 between 1 and 10 my.
Real‐time shock arrival predictions during the “Halloween 2003 epoch”
Authors: Dryer M. , Smith Z. , Fry C. D. , Sun W. , Deehr C. S. , Akasofu S.‐I.
Published: August 2004

The “Halloween” epoch from 19 October to 20 November 2003 was marked by 19 major solar flares that were accompanied by metric type II radio bursts. Several of these flares were followed by major geomagnetic storms. The radio bursts were used in real time because they imply coronal and interplanetary transport. Most of these events were also associated with halo (or partial halo) coronal mass ejections (CMEs). A continuing, widely distributed, real‐time research project called “fearless forecasts,” using an ensemble of four physics‐based models, has been made of the ensuing shock arrival times since 1997 at the L1 libration point. Model inputs include consideration of the type II shock speed estimates above the flare sites as well as preliminary CME leading edge speeds in the plane of sky. Thus the model ensemble used inputs that were guided by both speed estimates. The rationale for using CME speeds includes the assumption that their high speeds represented the shocks themselves in addition to an assumption concerning their quasi‐sphericity as they left the Sun. We compare the shock arrival predictions to those observed by the solar wind and magnetic field monitors on the Advanced Composition Explorer (ACE) and the solar wind monitor on the Solar and Heliospheric Observatory (SOHO) satellite. Success rates of the models are provided as a metric for this kind of active epoch. These success rates are 79% for one of the considered models using a “hit” window of ±24 hours and 74% when ±15 hours was used. This model demonstrates the importance of simulating both nonhomogeneous background environments and complex shock interactions.
Upstream entrainment in numerical simulations of spatially evolving round jets
Authors: Babu Pradeep C. , Mahesh Krishnan
Published: August 2004

Direct numerical simulation is used to study the effect of entrainment near the inflow nozzle on spatially evolving round jets. Inflow entrainment is obtained by providing a buffer region upstream of the inflow nozzle. Simulations are performed at Reynolds numbers of 300 (laminar) and 2400 (turbulent), respectively. Simulations without the inflow buffer are contrasted to those with the buffer region. The potential core is seen to close earlier in the presence of inflow entrainment. As a result, near-field turbulent intensities and pressure fluctuations on the jet centerline are noticeably affected. It is suggested that inflow entrainment results in an effective co-flow, whose effect on the volumetric flow rate near the inflow nozzle is appreciable for both laminar and turbulent jets. When plotted in similarity variables, the far-field solutions with and without inflow entrainment agree well with each other, and experiment. The results suggest the importance of allowing for inflow entrainment in simulations of turbulent jets, particularly for studies where near-field behavior is important.
Stability of convection induced by selective absorption of radiation in a fluid overlying a porous layer
Authors: Chang Min-Hsing
Published: August 2004

A linear stability analysis for the onset of convection induced by selective absorption of radiation in a two-layer system is presented. The system comprises a layer of fluid which lies above a porous layer saturated with the same fluid. The model for selective absorption of radiation is based on a similar one introduced by Krishnamurti [Dyn. Atmos. Oceans, 27, 367 (1997)] for a viscous fluid. Both the upper and lower surfaces are assumed to be fixed and it is found that the heating direction between both plates has a strong effect on the onset of convection. If the system is heated from below, the instability seems to have a bimodal nature in which convection may be dominated by fluid layer or by porous layer. While if heating from above, only one instability mode may exist in which convection is dominated by porous layer. Results for the stability characteristics with respect to the variations of depth ratio (the ratio of the depth of fluid layer to that of porous layer), strength of radiative heating, and Lewis number are also demonstrated in detail.
The impact of plant breeding on the grain yield and competitive ability of wheat in Australia
Authors: Vandeleur R. K. , Gill G. S.
Published: August 2004

Fourteen wheat (Triticum aestivum L.) cultivars released to Australian growers over the last century were examined to determine the impact of crop breeding on competitive ability with weeds. In 1999 and 2000 the weed used in the field study was annual ryegrass (Lolium rigidum Gaud.) and in 2001 oats (Avena sativa cv. Marloo) was the weedy competitor. In 2 out of 3 years (1999 and 2001), when Puccinia recondita (leaf rust) infection was not a problem, there were consistent trends for improvement in yielding ability through breeding effort over time. In these 2 seasons the yielding ability of wheat increased by around 15 kg/ha.year as compared with a yield increase of only 4.7 kg/ha.year in 2000 due to a heavy P. recondita infection. In 1999 and 2000, when annual ryegrass was used as the weedy competitor, there was no systematic trend for changes in crop yield loss with time (r = 0.47 in 1999; r = 0.08 in 2000, P > 0.05). However, in 2001, when oat was used as the weed, there was a significant positive linear relationship (r = 0.81, P < 0.01) between the year of cultivar release and crop yield loss, indicating inferior competitive ability of the modern cultivars. Old cultivars such as Nabawa not only provided superior weed suppression, they were also more tolerant of weeds as indicated by the smaller yield loss. Plant height appeared to be an important contributor to the superior competitiveness of the standard height, older cultivars. Other morphological traits contributing to superior competitive ability included greater leaf length and width, light interception, and flag leaf length. To improve the competitive ability of modern wheats without compromising their yielding ability, morphological traits that enhance early crop vigour (size of leaf 1 and 2) and light interception without affecting harvest index may need to be incorporated from carefully selected germplasm.
Type II platelet-activating factor-acetylhydrolase is essential for epithelial morphogenesis in
Caenorhabditis elegans
Authors: Inoue Takao , Sugimoto Asako , Suzuki Yuka , Yamamoto Masayuki , Tsujimoto Masafumi , Inoue Keizo , Aoki Junken , Arai Hiroyuki
Published: August 2004

Type II platelet-activating factor-acetylhydrolase [PAF-AH (II)] is an N-myristoylated enzyme that contains a lipase/esterase catalytic motif and selectively hydrolyzes the
sn
-2 acetyl ester of PAF and other short-chain acyl groups attached to phosphoglycerides. However, the physiological role of this enzyme remains to be elucidated. PAF-AH (II) is conserved in a variety of species ranging from a simple multicellular organism,
Caenorhabditis elegans
, to mammals.
C. elegans
possesses two homologous PAF-AH (II) genes, named
paf-1
and
paf-2
. In this study, we generated these two loss-of-function mutants to elucidate the
in vivo
PAF-AH (II) function. Surprisingly, mutants of
paf-2
, a major isoform of
C. elegans
PAF-AH (II)s, exhibits gross defects in epithelial sheet formation, resulting in unsuccessful subsequent morphogenesis with complete penetrance. Moreover,
paf-2
RNA interference worms show a variable abnormal morphology, including ectopic protrusions and a lumpy shape at the late embryonic and early larval stages due to epithelial organization defects. Consistent with these phenotypes, PAF-AH (II) is predominantly expressed in epithelial cells of
C. elegans
. This study demonstrates that PAF-AH (II) is essential for epithelial morphogenesis.
Lnk Inhibits Tpo–mpl Signaling and Tpo-mediated Megakaryocytopoiesis
Authors: Tong Wei , Lodish Harvey F.
Published: August 2004

Thrombopoietin (Tpo) is the primary cytokine regulating megakaryocyte development and platelet production. Tpo signaling through its receptor, c-mpl, activates multiple pathways including signal transducer and activator of transcription (STAT)3, STAT5, phosphoinositide 3-kinase–Akt, and p42/44 mitogen-activated protein kinase (MAPK). The adaptor protein Lnk is implicated in cytokine receptor and immunoreceptor signaling. Here, we show that Lnk overexpression negatively regulates Tpo-mediated cell proliferation and endomitosis in hematopoietic cell lines and primary hematopoietic cells. Lnk attenuates Tpo-induced S-phase progression in 32D cells expressing mpl, and Lnk decreases Tpo-dependent megakaryocyte growth in bone marrow (BM)–derived megakaryocyte culture. Consistent with this result, we found that in both BM and spleen, Lnk-deficient mice exhibited increased numbers of megakaryocytes with increased ploidy compared with wild-type mice. In addition, Lnk-deficient megakaryocytes derived from BM and spleen showed enhanced sensitivity to Tpo during culture. The absence of Lnk caused enhanced and prolonged Tpo induction of STAT3, STAT5, Akt, and MAPK signaling pathways in CD41+ megakaryocytes. Furthermore, the Src homology 2 domain of Lnk is essential for Lnk's inhibitory function. In contrast, the conserved tyrosine near the COOH terminus is dispensable and the pleckstrin homology domain of Lnk contributes to, but is not essential for, inhibiting Tpo-dependent 32D cell growth or megakaryocyte development. Thus, Lnk negatively modulates mpl signaling pathways and is important for Tpo-mediated megakaryocytopoiesis in vivo.
Influence of High-dose Aprotinin on Anticoagulation, Heparin Requirement, and Celite- and Kaolin-Activated Clotting Time in Heparin-pretreated Patients Undergoing Open-Heart Surgery
Authors: Dietrich W. , Dilthey G. , Spannagl M. , Jochum M. , Braun S. L. , Richter J. A.
Published: August 2004

Background

Aprotinin causes a prolongation of the celite-activated clotting time (CACT), but not of the kaolin-activated clotting time (KACT). Therefore, concern has been raised regarding the reliability of CACT to monitor anticoagulation in the presence of aprotinin. The current study was designed to test the efficacy of aprotinin to improve anticoagulation, and to investigate whether the prolongation of CACT reflects true anticoagulation or is an in vitro artifact. To elucidate this antithrombotic effect of aprotinin, this study was done in patients prone to reduced intraoperative heparin sensitivity.

Methods

In a prospective, randomized, double-blind clinical trial, 30 male patients scheduled for elective primary coronary revascularization and treated with heparin for at least 10 days preoperatively, received either high-dose aprotinin (group A) or placebo (group C). The CACT and KACT were determined, but only CACT was used to control anticoagulation with heparin. Parameters of coagulation that are indicators of thrombin generation and activity (F1+2 prothrombin fragments, thrombin-antithrombin III complex, and fibrin monomers), parameters of fibrinolysis (D-dimers), aprotinin, and heparin plasma concentrations were measured. Postoperative blood loss and allogeneic blood transfused were recorded.

Results

Total heparin administered was 36,200 units (95% confidence interval: 31,400-41,000; group C) compared with 27,700 (25,500-29,800) units (group A; P < 0.05). Hemostatic activation during cardiopulmonary bypass (CPB) was significantly reduced in group A compared with group C. After 60 min of CPB, all parameters were significantly different (P < 0.05) between the groups (group C vs. group A): F1+2 prothrombin fragments, 9.7 (8.9-11.7) ng/ml versus 7.5 (6.2-8.6) ng/ml; thrombin-anti-thrombin III complex (TAT), 53 (42-68) ng/ml versus 29 (23-38) ng/ml; and fibrin monomers, 23 (12-43) ng/ml versus 8 (3-17) ng/ml. Fibrinolysis was also attenuated; D-dimers at the end of operation were 656 (396-1,089) and 2,710 (1,811-4,055) ng/ml for groups A and C, respectively (P < 0.05). The CACT 5 min after the onset of CPB was 552 (485-627) versus 869 (793-955) s for groups C and A, respectively (P < 0.05), whereas the KACT showed no differences between the groups (569 [481-675] vs. 614 [541-697] s for groups C and A, respectively; P = NS). The 24-h blood loss was 1,496 (1,125-1,995) versus 597 (448-794) ml for groups C and A, respectively (P < 0.05).

Conclusions

Aprotinin treatment in combination with heparin leads to less thrombin generation during CPB. Aprotinin has anticoagulant properties. Celite-activated ACT is reliable for monitoring anticoagulation in the presence of aprotinin, because the prolonged CACT in the aprotinin group reflects improved anticoagulation. Kaolin-activated ACT does not reflect this effect of aprotinin.