bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upgrading of paper-grade pulps to dissolving pulps by nitren extraction: Optimisation of extraction parameters and application to different pulps
Authors: Janzon Ron , Puls Jürgen , Saake Bodo 
Published: July 2006

Abstract
Xylans were selectively removed from paper-grade pulps by nitren extraction to produce dissolving pulps. Extraction parameters were optimised for a birch kraft pulp regarding time, temperature, liquor/pulp ratio, and total nitren charge. Furthermore, the applicability of the method was investigated for two other kraft pulps obtained from eucalyptus and mixed softwood, and for one beech sulfite pulp. Extracted pulps were characterised regarding their carbohydrate content and Cuen viscosity. The nitren charge was a decisive factor for xylan removal and pulp purity. The combination of a high nitren concentration and low liquor/pulp ratio was most effective for xylan removal. However, a high liquor/pulp ratio with a lower nitren concentration proved to be more selective and minimised cellulose degradation as well. Glucomannans were almost insoluble under the extraction conditions investigated. Therefore, softwood pulps were not suitable for the upgrading of chemical pulps to dissolving pulps by nitren extraction. On the other hand, hardwood pulps obtained by kraft and sulfite processes contained 96–97% cellulose after nitren extraction.
The formation of aromatic end group structures in O-alkyl substituted celluloses under alkaline pulping conditions
Authors: Vikkula Anne , Vuorinen Tapani 
Published: July 2006

Abstract
UV resonance Raman (UVRR) spectroscopy was used to study changes in the structure of reducing end groups of O-alkyl substituted celluloses under conditions simulating the initial phase of soda pulping. The derivatives studied were carboxymethyl cellulose (CMC) with a degree of substitution (DS) of 0.58 and methyl cellulose (MC) with DS of 1.64–1.95. Hot alkaline treatments were carried out in solutions of sodium hydroxide (0.1–1 M) at 95°C in the presence of creosol as a lignin model compound. Alkali-stable aromatic end groups were generated in both cellulose ethers. Moreover, the end groups of methyl cellulose were extensively condensed with creosol. The results demonstrate that aromatisation and condensation depend on the pH and reaction time.
Kraft pulp from budworm-infested Jack pine
Authors: Zhu J.Y. , Myers Gary C. 
Published: July 2006

Abstract
This study evaluated the quality of kraft pulp from budworm-infested jack pine. The logs were classified as merchantable live, suspect, or merchantable dead. Raw materials were evaluated through visual inspection, analysis of the chemical composition, SilviScan measurement of the density, and measurement of the tracheid length. Unbleached pulps were then refined using a laboratory disk refiner. The mechanical and optical properties of handsheets made from the refined pulps were evaluated. Although budworm galleries may affect the physical integrity of the wood, they have no effect on pulp quality. Blue stain did not affect the handsheet brightness. The results indicate that merchantable dead jack pine trees are acceptable for kraft pulp production, with equivalent pulp yield.
Impact of drying temperature and pressing time factor on VOC emissions from OSB made of Scots pine
Authors: Makowski Mathias , Ohlmeyer Martin 
Published: July 2006

Abstract
Correlations between process parameters and VOC emissions from an oriented strand board (OSB) made of Scots pine (Pinus sylvestris L.) were demonstrated. Terpene and aldehyde emissions were affected by the pressing time factors in different ways: terpene emissions were lowered with elevated pressing times, whereas the formation of volatile aldehydes was accelerated. Drying temperature mainly affected the dynamics of aldehyde formation, with a clear rise and fall in aldehyde concentration after drying at elevated temperatures (170°C and >200°C). As a consequence of lower temperatures (120°C), aldehyde emissions from OSB constantly increased over the testing period. In spite of this context, a sustainable reduction in aldehyde emissions by adjusting the relevant process parameters does not seem to be feasible, as the concentrations released from all panels converged during emission testing.
Mechanical characterisation of wood-adhesive interphase cell walls by nanoindentation
Authors: Konnerth Johannes , Gindl Wolfgang 
Published: July 2006

Abstract
The elastic modulus, hardness, and creep factor of wood cell walls in the interphase region of four different adhesive bonds were determined by nanoindentation. In comparison with reference cell walls unaffected by adhesive, interphase cell walls from melamine-urea-formaldehyde (MUF) and phenol-resorcinol-formaldehyde (PRF) adhesive bonds showed improved hardness and reduced creep, as well as improved elastic modulus in the case of MUF. In contrast, cell walls from the interphase region in polyvinylacetate (PVAc) and one-component polyurethane (PUR) bonds showed more creep, but lower elastic modulus and hardness than the reference. Considering the different cell-wall penetration behaviour of the adhesive polymers studied here, it is concluded that damage and loss of elastic modulus to surface cells occurring during the machining of wood is recovered in MUF and PRF bond lines, whereas damage of cell walls persists in PVAc and PUR bond lines.
Influence of variation in modulus of elasticity on creep of wood during changing process of moisture
Authors: Takahashi Chika , Nakazawa Noriko , Ishibashi Kazuyuki , Iida Ikuho , Furuta Yuzo , Ishimaru Yutaka 
Published: July 2006

AbstractThis study considered the influence of variations in the modulus of elasticity (MOE) on the mechano-sorptive (MS) creep of wood. MOE in the radial direction (ER) was investigated as a function of changes in moisture content (MC).ERvalues were lower during both adsorption and desorption processes than under constant MC, despite the same MC values. However, the effects observed were small and are thus not of great practical importance.
Quantification of Coarse Aggregate Surface Texture Using Image Analysis
Authors: Pan T , Tutumluer E 
Published: July 2006

Abstract
Aggregate surface texture affects the performance of pavement and railroad track structural layers, such as the unbound aggregate base/ballast, asphalt concrete, and Portland cement concrete. A quantitative surface texture (ST) index is defined in this paper based on image analysis to measure the irregularities on the surface of coarse aggregate particles in the extent that is not characterized by the commonly used large-scale morphological descriptors, such as flatness, elongation, and angularity. Using an image analysis approach referred to as erosion and dilation, the new ST index quantifies the coarse aggregate surface irregularities at the pixel level. Samples of natural gravel and crushed aggregate were used in establishing a realistic range for the ST index independent of particle size. The effectiveness and practical applicability of the defined ST index in characterizing aggregate surface texture were evaluated by measuring surface irregularities or texture of commonly used coarse aggregate materials.
Verfolgung, Selbsthilfe, Liquidation. Jüdische Genossenschaftsbanken im nationalsozialistischen Deutschland 1933–1938
Authors: Fischer Albert 
Published: July 2006

Vorspann
Anders als über die jüdischen Privatbanken im Dritten Reich wissen wir über die meist erst 1933 entstehenden Genossenschaftsbanken noch immer recht wenig. Ihre wechselvolle Geschichte, in der sich die Verdrängung der Juden aus der deutschen Wirtschaft spiegelt, untersucht Albert Fischer mit Blick auf mehrere Fragen: Welches waren die Gründe für das sprunghafte Wachstum der jüdischen Genossenschaftsbanken seit 1933? Wie entwickelte sich ihr Verhältnis zur „arischen“ Bankenwelt und zu den Behörden des NS-Staates? Und weshalb schließlich konnten sich Reichsinnen- und Reichswirtschaftsministerium 1937/38 bei der Zerschlagung dieser Banken gegen das Justiz- und Arbeitsministerium durchsetzen?
Zwischen Pax Americana und Pakt Atomica. Das deutsch-amerikanische Verhältnis während der EURATOM-Verhandlungen 1955–1957
Authors: Segers Mathieu L.L. 
Published: July 2006

Vorspann
Die Gründung der Europäischen Atomgemeinschaft (EURATOM) war mehr als nur ein innereuropäischer Prozess. Anhand neuer Akten kann der Verfasser nachweisen, dass die Politik, die die Bundesregierung in dieser Frage verfolgte, nur im Kontext der amerikanischen Außenpolitik verstanden werden kann.
Risk Factors for Congenital Cytomegalovirus Infection in the Offspring of Young Women: Exposure to Young Children and Recent Onset of Sexual Activity
Authors: Fowler Karen B. , Pass Robert F. 
Published: July 2006

OBJECTIVE. Two recognized sources of maternal cytomegalovirus infection are young children and sexual activity. Previous studies evaluated either maternal exposures to young children or sexual activity, but these studies did not evaluate whether both of these maternal cytomegalovirus sources contribute to increases in congenital cytomegalovirus infections within populations with a high prevalence of infection among women of childbearing age. Our objective with this study was to investigate whether maternal cytomegalovirus exposure through young children and by sexual activity increases the risk for congenital cytomegalovirus infection in their offspring.METHODS. A case-control study of 519 women from a delivery population in Birmingham, AL, between December 1992 and July 1998 was undertaken to measure the association between maternal cytomegalovirus exposures and an increased risk for congenital cytomegalovirus infection in their infants. Routine newborn cytomegalovirus screening at the hospital identified infants with congenital cytomegalovirus infection. The cases (n = 150) were women who delivered an infant with congenital cytomegalovirus infection, and the control subjects (n = 369) were randomly selected from the delivery population of women whose newborns were uninfected. Investigation of exposures included using a standardized maternal interview, prenatal and medical chart abstraction, and laboratory confirmation of cytomegalovirus infection.RESULTS. Significant associations between congenital cytomegalovirus infection and caring for preschool children in the year before delivery, onset of sexual activity &lt;2 years before delivery, sexually transmitted diseases during pregnancy, household size &gt;3 people, and maternal age &lt;25 years were identified. Women who cared for preschool children in the year before delivery and also became sexually active within the 2 years before delivery were at greatest risk for delivering an infant with congenital cytomegalovirus infection.CONCLUSIONS. Caring for young children and recent onset of sexual activity contribute to an increased risk for congenital cytomegalovirus infection in the offspring of young women.
Persistent Humoral Immune Defect in Highly Active Antiretroviral Therapy–Treated Children With HIV-1 Infection: Loss of Specific Antibodies Against Attenuated Vaccine Strains and Natural Viral Infection
Authors: Bekker Vincent , Scherpbier Henriëtte , Pajkrt Dasja , Jurriaans Suzanne , Zaaijer Hans , Kuijpers Taco W. 
Published: July 2006

OBJECTIVE. In the pre–highly active antiretroviral therapy era, a loss of specific antibodies was seen. Our objective with this study was to describe the loss of specific antibodies during treatment with highly active antiretroviral therapy.METHODS. In a prospective, single-center, cohort study of 59 children with HIV-1 infection, we investigated the long-term effect of highly active antiretroviral therapy on the titers and course of specific antibodies against measles, mumps, and rubella vaccine strains compared with wild-type varicella zoster virus, cytomegalovirus, and Epstein-Barr virus.RESULTS. During highly active antiretroviral therapy, age-adjusted CD4+ T cells and B cells increased, whereas total immunoglobulin levels declined. Although these children were preimmunized before the start of highly active antiretroviral therapy, only 24 (43%) had antibodies against all 3 measles, mumps, and rubella. Antibodies against measles, mumps, and rubella were lost in 14 (40%), 11 (38%), and 5 (11%) children who were seropositive at baseline. We also observed loss of varicella zoster virus immunoglobulin G in 7 (21%) of 34, cytomegalovirus immunoglobulin G in 3 (7%) of 45, but none of 53 Epstein-Barr virus–seropositive children. During highly active antiretroviral therapy, primary vaccination in 3 patients and 15 revaccinations in those with negative serology demonstrated incomplete seroconversion.CONCLUSIONS. Humoral reactivity in children with HIV-1 infection remains abnormal during highly active antiretroviral therapy. Despite immune reconstitution, antibodies against live-attenuated vaccine and wild-type natural virus strains disappear over time in up to 40% of children with HIV-1 infection.
Conidial Pigmentation Is Important to Tolerance Against Solar‐simulated Radiation in the Entornopathogenic Fungus Metarhizium anisopliae
Authors: Brags Gilberto U. L. , Rangel Drauzio E. N. , Flint Stephan D. , Anderson Anne J. , Roberts Donald W. 
Published: July 2006

ABSTRACTThe importance of conidial pigmentation to solar UV radiation tolerance in the entomopathogenic fungus Metarhizium anisopliae var. anisopliae, was estimated by comparing the effects of exposure to simulated solar UV radiation on the wild‐type parent strain U.S. Department of Agriculture (USDA)‐Agri‐cultural Research Service (ARS) Collection of Entomopathogenic Fungal Cultures (ARSEF) 23, which has dark green conidia, and three groups of color mutants with yellow, purple and white conidia. The comparisons included inactivation levels and the kinetics of germination of conidia exposed or not exposed to simulated solar UV radiation. In addition to significantly inactivating the conidia of different mutants, exposure to radiation delayed for several hours the germination of surviving conidia of the wild type and all mutants. In general, mutants with white conidia were more sensitive to simulated solar UV radiation than mutants with purple conidia, which were more sensitive than mutants with yellow conidia, which in turn were more sensitive than the green wild strain. A significant variation in tolerance to simulated solar radiation was observed among mutants within each color group, particularly among mutants with yellow conidia. Revertants with green conidia, DWR 179 and DWR 176, were obtained from the very sensitive UV mutants DWR 148 (yellow conidia) and DWR 149 (purple conidia), respectively. These revertants had levels of tolerance to simulated solar UV radiation similar to those of the wild‐type ARSEF 23. This observation is strong evidence of the importance of green conidial pigmentation for tolerance to simulated solar UV radiation, a factor that could be manipulated to produce M. anisopliae strains with more tolerance to solar UV radiation.
Microwave Treatment of Eight Seconds Protects Cells of lsafis indigofica from Enhanced UV‐8 Radiation Lesions
Authors: Chen Yi‐Ping 
Published: July 2006

ABSTRACTTo determine the role of microwaves in the stress resistance of plants to enhanced ultraviolet‐B (UV‐B) radiation, Isatis indigotica Fort. seeds were subjected to microwave radiation for 8 s (wavelength 125 mm, power density 1.26 mW mm‐2, 2450 MHz). Afterwards they were cultivated in plastic pots in an artificial‐glass greenhouse maintained at 25°C, 70% relative humidity, and 400 pmol mol‐1 CO2, under visible‐light conditions of 1500 pmol m‐2 s‐l for 8 h day‐1. When the seedlings were 10 days old, they were subjected to 10.08 kJ m‐2 UV‐B (PAR: 220 μmol m‐2 s‐1) radiation for 8 days. Changes in a number of physiological and biochemical characteristics and in the thermal decomposition enthalpy of biomass were measured and used as indicators of the protective capacity of microwave radiation in this experiment. Our results revealed that microwave pretreatment of seeds enhanced UV‐B stress resistance in the seedlings by decreasing the concentration of malondialdehyde (MDA) and increasing the concentration of ascorbic acid (AsA) and UV‐B‐absorbing compounds, increasing the activities of catalase (CAT), per‐oxidase (POD), and superoxide dismutase (SOD), and increasing the energy accumulation of photosynthesis. All these results suggest that microwave radiation enhances plant metabolism and results in increased UV‐B stress resistance. This is the first investigation reporting the use of microwave pretreatment to protect the cells of Isatis indigotica from UV‐B‐induced lesions.
A New Analytical Tire Model for Cornering Simulation. Part II: Cornering Force and Self-aligning Torque
Authors: Miyashita N. , Kabe K. 
Published: July 2006

Abstract
An analytical tire model for cornering force (CF) and self-aligning torque (SAT) is described on the basis of the Fiala model. CF and SAT come mainly from the shear stress and sliding friction at the tread/road interface. The CF and SAT variations also change the kinetic conditions for their own generations, that is, the contact-pressure distribution, the tire-part deformation, and the relative position of the steering axis within the contact patch. The present model, the CF/SAT system model, which includes these conditional changes through the CF and SAT feedback loops, approximates the slip-angle dependence of CF and SAT with high accuracy. The inverse data analysis, that is, least-squares fittings of the measured data to the model, give some experimental information about the tread friction coefficient (the adhesive and sliding friction coefficient) and the variation in contact-pressure distribution during cornering. The CF/SAT system model, as well as the CP/SATP model in Part I, may be useful for both the tire production at tire makers and the vehicle dynamics simulation at car makers.
Improved Enantioselectivity of Immobilized Chiral Bisoxazolines by Partial Precapping of the Siliceous Mesocellular Foam Support with Trimethylsilyl Groups
Authors: Lee Su Seong , Hadinoto Sukandar , Ying Jackie Y. 
Published: July 2006

AbstractSiliceous mesocellular foams (MCF) were partially surface‐modified with trimethylsilyl (TMS) groups prior to the immobilization of chiral tert‐butylbisoxazolines. The resulting MCF‐supported bisoxazoline‐Cu(I) catalyst showed superior enantioselectivity (up to 95 % ee) in asymmetric cyclopropanation, compared to that supported on MCF without TMS precapping. This heterogenized catalyst also exhibited excellent recyclability.
Influence of Elevated Temperature and Pressure on the Chromium‐Catalysed Tetramerisation of Ethylene
Authors: Kuhlmann Sven , Dixon John T. , Haumann Marco , Morgan David H. , Ofili Jimmy , Spuhl Oliver , Taccardi Nicola , Wasserscheid Peter 
Published: July 2006

AbstractA catalyst system comprising a diphenylphosphineamine (PNP) ligand, chromium(III) acetylacetonate and a methylaluminoxane‐based activator was studied for the selective tetramerisation of ethylene. The reaction was investigated over a broad temperature and pressure range and the resulting product mixture was interpreted in the light of the recently published, enlarged metallacycle mechanism. Vapour‐liquid equilibrium (VLE) data were calculated for the binary ethylene‐cyclohexane mixture over the relevant temperature and pressure ranges to deconvolute the influence of ethylene concentration and temperature. Good agreement of the experimental data with the proposed mechanism was found. Enlargement of the metallacycloheptane ring by insertion of ethylene was found to be dependent on the ethylene concentration, albeit to a lesser extent than assumed. The 1‐octene selectivity, which reaches a maximum of 72–74 mass %, thus seems to be primarily dependent on the temperature. The formation of the cyclic side products methyl‐ and methylenecyclopentane was in effect independent of the ethylene concentration. This is in good accordance with the proposed mechanism, since it indicates that the formation of the products occurs via rearrangement of a metallacycle intermediate.
Ruthenium‐Catalyzed Enantioselective Reduction of Electron‐Rich Aryl Alkyl Ketones
Authors: Wettergren Jenny , Bøgevig Anders , Portier Maud , Adolfsson Hans 
Published: July 2006

AbstractPresented here is the investigation of the transfer hydrogenation of electron‐rich aryl alkyl ketones using ruthenium complexes of dipeptide‐like ligands and 2‐propanol as hydride source. The reduction proceeded with excellent selectivity (up to>99 % ee) and in moderate to high yields (up to 90 %).
Asymmetric Reductive Amination: Convenient Access to Enantioenriched Alkyl‐Alkyl or Aryl‐Alkyl Substituted α‐Chiral Primary Amines
Authors: Nugent Thomas C. , Ghosh Abhijit K. , Wakchaure Vijay N. , Mohanty Rashmi R. 
Published: July 2006

AbstractA two‐step procedure for producing optically active, high value primary amines has been developed. The first and key step is the asymmetric reductive amination of a prochiral alkyl alkyl (acyclic or cyclic) or aryl alkyl (acyclic or cyclic) ketone with (R)‐ or (S)‐α‐methylbenzylamine (α‐MBA). The normally stepwise excessive procedures of chiral auxiliary approaches are avoided by simultaneously incorporating the auxiliary and a new stereogenic center at the former carbonyl carbon of the ketone during step one. Specifically, step one is the hydrogenation (4–8 bar) of a prochiral ketone substrate in the presence of α‐MBA, a Lewis acid [Ti(O‐i‐Pr)4, B(O‐i‐Pr)3, Al(O‐i‐Pr)3, or Zr(O‐i‐Pr)4], and a heterogeneous hydrogenation catalyst (Raney‐Ni, Pt‐C, Pd‐C, Ru‐C, or Rh‐C), providing the amine diastereomers 2 in good to excellent yield and diastereoselectivity. Depending on the ketone examined (acyclic vs. cyclic, alkyl alkyl vs. aryl alkyl, sterically encumbered vs. unencumbered), the correct combination of heterogeneous hydrogenation catalyst, solvent, and temperature is crucial for allowing high yield and de with practical reaction times (generally 6–20 h). Performing the reaction in the absence of one of the indicated Lewis acids results in the formation of large amounts of alcohol by‐product (>25 %). Step two, hydrogenolysis, allows smooth removal of the chiral auxiliary providing α‐chiral primary amines in good overall yield (5 examples 71–78 %, 1 example 64 %) and in 66–98 % enantiomeric excess. This two‐step strategy is noteworthy because: 1) it is yield and stepwise efficient; 2) all the reagents are inexpensive and already used by the pharmaceutical industry; 3) a broad range of ketone substrates are suitable; 4) either enantiomeric form of the α‐chiral amine product can be produced; 5) the reaction conditions are mild; and 6) the process is amenable to scale‐up.
Heterogeneous Gold‐Catalysed Synthesis of Phenols
Authors: Carrettin Silvio , Blanco M. Carmen , Corma Avelino , Hashmi A. Stephen K. 
Published: July 2006

AbstractNanoparticles of gold supported on nanocrystalline CeO2 catalyse the isomerisation of ω‐alkynylfurans to phenols. Initial leaching of gold was observed, which could be minimised by calcining. Subsequent runs showed that once all soluble species had leached, the surface‐bound, cationic gold species is still active and can reach turnover numbers of up to 391. This is the first time that a heterogeneous gold catalyst showed activity in the gold‐catalysed phenol synthesis.
Efficient, Enantioselective Organocatalytic Synthesis of Trichostatin A
Authors: Zhang Shilei , Duan Wenhu , Wang Wei 
Published: July 2006

AbstractAn efficient, highly stereocontrolled total synthesis of trichostatin A (1) has been achieved in 9 steps with 17.4 % overall yield and >99 % optical purity from readily available achiral starting materials. The key features of this synthesis include the L‐proline‐promoted, highly enantioselective cross‐aldol reaction as a crucial step for the construction of the C‐6 chiral center and the minimization of racemization by final step oxidation of the OH group to a ketone at position 7.