bluuebunny/crossref_metadata_2025 huggingface dataset:
Fast and accurate predictions of binding free energies using MM‐PBSA and MM‐GBSA
Authors: Rastelli Giulio , Rio Alberto Del , Degliesposti Gianluca , Sgobba Miriam
Published: June 2009

In the drug discovery process, accurate methods of computing the affinity of small molecules with a biological target are strongly needed. This is particularly true for molecular docking and virtual screening methods, which use approximated scoring functions and struggle in estimating binding energies in correlation with experimental values. Among the various methods, MM‐PBSA and MM‐GBSA are emerging as useful and effective approaches. Although these methods are typically applied to large collections of equilibrated structures of protein‐ligand complexes sampled during molecular dynamics in water, the possibility to reliably estimate ligand affinity using a single energy‐minimized structure and implicit solvation models has not been explored in sufficient detail. Herein, we thoroughly investigate this hypothesis by comparing different methods for the generation of protein‐ligand complexes and diverse methods for free energy prediction for their ability to correlate with experimental values. The methods were tested on a series of structurally diverse inhibitors of Plasmodium falciparum DHFR with known binding mode and measured affinities. The results showed that correlations between MM‐PBSA or MM‐GBSA binding free energies with experimental affinities were in most cases excellent. Importantly, we found that correlations obtained with the use of a single protein‐ligand minimized structure and with implicit solvation models were similar to those obtained after averaging over multiple MD snapshots with explicit water molecules, with consequent save of computing time without loss of accuracy. When applied to a virtual screening experiment, such an approach proved to discriminate between true binders and decoy molecules and yielded significantly better enrichment curves. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010
On the methane adsorption capacity of activated carbons: in search of a correlation with adsorbent properties
Authors: Contreras M. , Lagos G. , Escalona N. , Soto‐Garrido G. , Radovic L.R. , Garcia R.
Published: June 2009

BACKGROUND: There exists now a widely held view that the methane storage capacity on an activated carbon is not related to any of the routinely determined properties of the adsorbent, such as surface area or micropore volume. This has been confirmed and a correlation pursued with other physical and/or chemical properties of both commercially available carbons and those prepared in the laboratory. Textural characteristics (from nitrogen adsorption isotherms at 77 K) considered were BET‐equivalent specific surface area, DR micropore volume and Horvath–Kawazoe micropore size distribution. Chemical properties were evaluated using Fourier transform infrared (FTIR) spectroscopy, thermal programmed decomposition (TPD) and Boehm titrations. Both kinetic and equilibrium methane adsorption experiments were performed at 273 and 298 K and up to 3.5 MPa.

RESULTS: Using phosphoric acid to activate peach stones together with additional thermal treatment enabled the production of activated carbons with 137 v/v methane adsorption capacity at 298 K.

CONCLUSIONS: The presence of acidic surface functional groups has a detrimental influence on methane uptake, due to the chemical inertness of the adsorbate and/or to pore blockage of the adsorbent. Basic surface functional groups (pyrone), together with a desirable pore size distribution centered at ca 0.8 nm, are thought to be responsible for improved methane adsorption capacity on such activated carbons. Copyright © 2009 Society of Chemical Industry
Pre‐, intra‐, and postoperative sonography of the abdominal wall in patients with incisional hernias repaired via a three‐layered operative suture method
Authors: den Hartog Dennis , Dur Alfons H. M. , Kamphuis Alfons G. A. , Tuinebreijer Wim E. , Hermans John J. , Kreis Robert W.
Published: June 2009

We illustrate the various sonographic (US) appearances of the abdominal wall following this type of repair, including partial and complete recurrences. Correlation is made with CT imaging. The three‐layered anatomical reconstruction of an incisional hernia is described. © 2009 Wiley Periodicals, Inc. J Clin Ultrasound, 2009
A simple method for multiday imaging of slice cultures
Authors: Seidl Armin H. , Rubel Edwin W
Published: June 2009

The organotypic slice culture (Stoppini et al. A simple method for organotypic cultures of nervous tissue. 1991;37:173‐182) has become the method of choice to answer a variety of questions in neuroscience. For many experiments, however, it would be beneficial to image or manipulate a slice culture repeatedly, for example, over the course of many days. We prepared organotypic slice cultures of the auditory brainstem of P3 and P4 mice and kept them in vitro for up to 4 weeks. Single cells in the auditory brainstem were transfected with plasmids expressing fluorescent proteins by way of electroporation (Haas et al. Single‐cell electroporation for gene transfer in vivo. 2001;29:583‐591). The culture was then placed in a chamber perfused with oxygenated ACSF and the labeled cell imaged with an inverted wide‐field microscope repeatedly for multiple days, recording several time‐points per day, before returning the slice to the incubator. We describe a simple method to image a slice culture preparation during the course of multiple days and over many continuous hours, without noticeable damage to the tissue or photobleaching. Our method uses a simple, inexpensive custom‐built insulator constructed around the microscope to maintain controlled temperature and uses a perfusion chamber as used for in vitro slice recordings. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.
Changes in MAPK pathway in neonatal and adult testis following fetal estrogen exposure and effects on rat testicular cells
Authors: Thuillier Raphael , Manku Gurpreet , Wang Yan , Culty Martine
Published: June 2009

Concerns have been raised about the possible role of the phytoestrogen genistein and the xenoestrogen Bisphenol A (BPA) as endocrine disruptors. In the present study, we examined the effects of fetal exposure to genistein and BPA on the Mitogen‐activated protein kinase (MAPK) pathway and on testicular cell populations in neonatal and adult rat testes. At postnatal day (PND) 3, genistein (0.1–10 mg/kg/day) and BPA (1–200 mg/kg/day) induced Raf1 and Erk1/2 mRNA and protein increases in testes, mainly in Sertoli cells. No changes were seen for Mek1. At PND60, Erk1/2 protein expression remained robust in Sertoli cells and in some spermatogonia. Raf1 was predominant in Leydig cells while Mek1 was expressed strongly in spermatogonia, and they were both expressed in pachytene spermatocytes. No consistent change was seen in these proteins at PND60. Transient effects were observed on germ cell populations, while the only remaining effect on adult testicular cells was an increase in Leydig cell number. Rats exposed in utero to the two compounds did not present significant changes in circulating testosterone levels, suggesting normally functioning adult Leydig cells. Furthermore, Sertoli cell numbers were not affected by exposure to genistein and BPA. Finally, around 10% of genistein and BPA exposed rats were sterile, whereas all control rats were fertile. These data suggest that fetal exposure to genistein and BPA exerts transient effects in rat testes and that the changes observed at PND3 did not correlate with relevant changes in germ cell populations, Leydig cell function, or fertility in the adult. Microsc. Res. Tech., 2009. © 2009 Wiley‐Liss, Inc.
Facile and selective solvent‐free synthesis of 2‐isoxazolines under microwave irradiation
Authors: Mouradzadegun Arash , Dianat Shima
Published: June 2009

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Triarylpyrylium perchlorates are readily and selectively converted into corresponding 2‐isoxazolines in good yield and short reaction time using solventless conditions. J. Heterocyclic Chem., (2009).
Junjappa‐Ila annulation: α‐Oxoketene dithioacetal mediated synthesis of substituted benzotriazoles
Authors: Shetty Nitinkumar S. , Lamani Ravi S. , Panchamukhi Shridhar I. , Khazi Imtiyaz Ahmed M.
Published: June 2009

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2‐(1‐Benzyl‐1H–1,2,3‐triazole‐4‐yl)‐3‐methylsulfanyl‐5‐oxo‐5‐substituted‐pent‐2‐enenitrile3a,3b,3c,3d,3ewere obtained in good yields by condensation of (1‐benzyl‐1H‐1,2,3‐triazole‐4‐yl)acetonitrile1with various α‐oxoketene dithioacetals2a,2b,2c,2d,2ein the presence of sodium hydride. The intermediates3a,3b,3c,3d,3eunderwent facile acid‐induced cyclization in the presence of PTSA to afford the corresponding benzotriazoles4a,4b,4c,4d,4ein moderate yields. J. Heterocyclic Chem., (2009).
Chemically modified porous silicon for laser desorption/ionization mass spectrometry of ionic dyes
Authors: Shmigol I. V. , Alekseev S. A. , Lavrynenko O. Yu. , Vasylieva N. S. , Zaitsev V. N. , Barbier D. , Pokrovsky V. A.
Published: June 2009

Desorption/ionization on silicon (DIOS) mass spectra of model ionic dyes methylene blue (MB+Cl−) and methyl orange (Na+MO−) were studied using p+ type‐derived porous silicon (PS) free layers. As‐prepared PS (PS‐H), the PS thermally oxidized at 300 °C (PS‐OX), PS with chemically grafted cation‐exchanging alkylsulfonic acid (PS‐SO3H) and anion‐exchanging propyl‐octadecyldimethylammonium chloride (PS‐ODMA+Cl−) groups was tested as ionization platforms. Two mechanisms of the methylene blue desorption/ionization were found: (1) the formation of [MB + H]+• ion due to the reduction/protonation of MB+, which is predominant for PS‐H and PS‐OX platforms and (2) direct thermal desorption of the MB+ cation, prevailing for PS‐SO3H. The fragmentation of the cation is significantly suppressed in the latter case. The samples of PS‐SO3H and PS‐ODMA+ Cl− efficiently adsorb the dyes of the opposite charge from their solutions via the ion‐exchange. Consequent DIOS MS studies allow to detect only low fragmented ions (MB+ and MO−, respectively), demonstrating the potential of the ion‐exchange adsorption combined with DIOS MS for the analysis of ionic organic compounds in solutions. Copyright © 2009 John Wiley & Sons, Ltd.
Proteasome inhibition modulates kinase activation in neural cells: Relevence to ubiquitination, ribosomes, and survival
Authors: Zhang Le , Ebenezer Philip J. , Dasuri Kalavathi , Bruce‐Keller Annadora J. , Liu Ying , Keller Jeffrey N.
Published: June 2009

In this study we examined whether established signal transduction cascades, p44/42 mitogen‐activated protein kinase (ERK1/2) and Jun N‐terminal kinases (JNK) pathways, are altered in N2a neural cells in response to proteasome inhibition. Additionally, we sought to elucidate the relative contribution of these signal transduction pathways to the multiple downstream effects of proteasome inhibition. Our data indicate that ERK1/2 and JNK are activated in response to proteasome inhibition. Washout of proteasome inhibitor (MG132) results in an enhancement of ERK1/2 activation and amelioration of JNK activation. Treatment with an established MAPK inhibitor resulted in an increase in proteasome inhibitor toxicity, and incubation with JNK inhibitor was observed to attenuate proteasome inhibitor toxicity significantly. Subsequent studies demonstrated that inhibition of ERK1/2 and JNK activity does not alter the gross increase in ubiquitinated protein following proteasome inhibitor administration. Similarly, ERK1/2 and JNK activity do not appear to play a role in the disruption of polysomes following proteasome inhibitor administration in neural cells. Together these data indicate that ERK1/2 and JNK activation may play differential roles in modulating neurochemical disturbances and neurotoxicity induced by proteasome inhibition. © 2009 Wiley‐Liss, Inc.
Environmental enrichment stimulates progenitor cell proliferation in the amygdala
Authors: Okuda Hiroaki , Tatsumi Kouko , Makinodan Manabu , Yamauchi Takahira , Kishimoto Toshifumi , Wanaka Akio
Published: June 2009

Enriched environments enhance hippocampal neurogenesis, synaptic efficacy, and learning and memory functions. Recent studies have demonstrated that enriched environments can restore learning behavior and long‐term memory after significant brain atrophy and neural loss. Emotional and anxiety‐related behaviors were also improved by enriched stimuli, but the effect of enriched environments on the amygdala, one of the major emotion‐related structures in the central nervous system, remains largely unknown. In this study, we have focused on the effects of an enriched environment on cell proliferation and differentiation in the murine amygdala. The enriched environment increased bromodeoxyuridine (BrdU)‐positive (newborn) cell numbers in the amygdala, almost all of which, immediately after a 1‐week period of enrichment, expressed the oligodendrocyte progenitor marker Olig2. Furthermore, enriched stimuli significantly suppressed cell death in the amygdala. Some of the BrdU‐positive cells in mice exposed to the enriched environment, but none in animals housed in the standard environment, later differentiated into astrocytes. Our findings, taken together with previous behavioral studies, suggest that progenitor proliferation and differentiation in the amygdala may contribute to the beneficial aspects of environmental enrichment such as anxiolytic effects. © 2009 Wiley‐Liss, Inc.
Sodium channelopathy induced by mild axonal trauma worsens outcome after a repeat injury
Authors: Yuen Tracy J. , Browne Kevin D. , Iwata Akira , Smith Douglas H.
Published: June 2009

There is great concern that one mild traumatic brain injury (mTBI) predisposes individuals to an exacerbated response with a subsequent mTBI. Although no mechanism has been identified, mounting evidence suggests traumatic axonal injury (TAI) plays a role in this process. By using a cell culture system, a threshold of mild TAI was found where dynamic stretch of cortical axons at strains lower than 5% induced no overt pathological changes. However, the axons were found to display an increased expression of sodium channels (NaChs) by 24 hr. After a second, identical mild injury, pathologic increases in [Ca2+]i were observed, leading to axon degeneration. The central role of NaChs in this response was demonstrated by blocking NaChs with tetrodotoxin prior to the second injury, which completely abolished postinjury increases in [Ca2+]i. These data suggest that mild TAI induces a form of sodium channelopathy on axons that greatly exaggerates the pathophysiologic response to subsequent mild injuries. © 2009 Wiley‐Liss, Inc.
Deficits in peroneal latency and electromechanical delay in patients with functional ankle instability
Authors: Hopkins J. Ty , Brown Tyler N. , Christensen Logan , Palmieri‐Smith Riann M.
Published: June 2009

The purpose of this study was to compare alterations in peroneal latency and electromechanical delay (EMD) following an inversion perturbation during walking in patients with functional ankle instability (FAI) and with a matched control group. Peroneal latency and EMD were measured from 21 patients with unilateral FAI and 21 controls. Latencies were collected during a random inversion perturbation while walking. EMD measures were collected during stance using a percutaneous stimulus. Two‐way ANOVAs were used to detect differences between leg (affected, unaffected) and group (FAI, Control). Functionally unstable ankles displayed delayed peroneus longus (PL) latencies and EMD when compared to the unaffected leg and a matched control group. Peroneal latency and EMD deficits could contribute to recurrence of ankle injury in FAI subjects. How these deficits are associated with the chronic symptoms associated with FAI remains unclear, but gamma activation and subsequent muscle spindle sensitivity likely play a role. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27:1541–1546, 2009
Sensitive determination of 1‐ and 2‐naphthol in human plasma by HPLC‐fluorescence detection with 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)benzoyl chloride as a labeling reagent
Authors: Ohyama Kaname , Kishikawa Naoya , Matayoshi Kenji , Adutwum Lawrence Asamoah , Wada Mitsuhiro , Nakashima Kenichiro , Kuroda Naotaka
Published: June 2009

A sensitive HPLC‐fluorescence (FL) method with FL‐labeling reagent for simultaneous determination of 1‐ and 2‐naphthol was developed. The FL‐labeling reaction of naphthols with 4‐(4,5‐diphenyl‐1H‐imidazol‐2‐yl)benzoyl chloride (DIB‐Cl) was completed in 20 min at 40°C. The separation of DIB derivatives was achieved with an ODS column and isocratic elution. The LODs of 1‐ and 2‐naphthol were 16 fmol and 14 fmol/injection, respectively, which were 5‐fold and 14‐fold lower than those obtained by HPLC‐FL method using the native FL of naphthols. The DIB‐naphthol derivatives were stable for at least 24 h even when they were placed at room temperature. The proposed method was applied to the measurement of 1‐ and 2‐naphthol in human plasma with sufficient accuracy (90.8–109%) and precision (< 6.3%).
Simultaneous analysis of morphine‐related compounds in plasma using mixed‐mode solid phase extraction and UltraPerformance liquid chromatography–mass spectrometry
Authors: Fountain Kenneth J. , Yin Zhe , Diehl Diane M.
Published: June 2009

A bioanalytical method using mixed‐mode solid phase extraction and UltraPerformance liquid chromatography‐tandem mass spectrometry (UPLC–MS/MS) was developed for the analysis of morphine, morphine‐3β‐glucuronide, morphine‐6β‐glucuronide, 6‐acetylmorphine, morphineN‐oxide, and 10‐hydroxymorphine in porcine plasma. All six compounds, along with four deuterated internal standards, were simultaneously extracted using mixed‐mode strong cation exchange SPE in a 96‐well μElution plate format. Due to analyte instability, a neutralizing solvent was used during the elution step to minimize degradation of 6‐acetylmorphine. Separation was subsequently performed in 8 minutes on a 2.1×100 mm, 1.8 μm C18column designed for retention of extremely polar compounds using a formic acid and methanol gradient. Analytes were detected by positive electrospray ionization in multiple reaction monitoring mode using a fast‐scanning triple quadrupole mass spectrometer. Recovery was 73–123% depending on the analyte, and inter‐day variability was less than 6%. Linearity was determined in porcine plasma by spiking the analytes prior to SPE. Correlation coefficients were ⪈ 0.998, and% deviation from the actual concentrations was less than 15%. The lower limit of quantitation (LLOQ) for all compounds was between 0.1 and 0.25 ng/mL.
Development of a GC×GC–TOFMS method using SPME to determine volatile compounds in cacao beans
Authors: Humston Elizabeth M. , Zhang Yan , Brabeck Gregory F. , McShea Andrew , Synovec Robert E.
Published: June 2009

A method to analyze volatile compounds from cacao beans has been developed and evaluated. The method utilizes solid phase micro extraction (SPME) sampling followed by comprehensive 2‐D (GC×GC) coupled with TOFMS. For the SPME procedure, a polydimethyl siloxane/divinyl benzene (PDMS/DVB) fiber was implemented. Cacao beans from four geographical origins were studied under two storage conditions, either dry or high moisture. A given cacao bean sample was sealed in a SPME vial and heated for 15 min. Extraction temperatures of 45, 60, 80, and 100°C were analyzed and an optimal extraction temperature of 60°C was determined. Many peaks were found to change as a function of storage conditions with Fisher Ratio analysis. Four representative compounds were identified and quantified (on a relative basis): acetic acid, nonanal, tetramethyl pyrazine, and trimethyl pyrazine. Acetic acid and nonanal were elevated in samples without evident mold on the bean surface, while the two pyrazines were elevated when mold was evident on the bean surface. The results for these comparisons, indicate that metabolism at the bean surface plays a role in the concentration of analytes, and can be readily determined using this analytical technology and methodology.
Analytical and statistical approaches to metabolomics research
Authors: Issaq Haleem J. , Van Que N. , Waybright Timothy J. , Muschik Gary M. , Veenstra Timothy D.
Published: June 2009

Metabolomics, the global profiling of metabolites in different living systems, has experienced a rekindling of interest partially due to the improved detection capabilities of the instrumental techniques currently being used in this area of biomedical research. The analytical methods of choice for the analysis of metabolites in search of disease biomarkers in biological specimens, and for the study of various low molecular weight metabolic pathways include NMR spectroscopy, GC/MS, CE/MS, and HPLC/MS. Global metabolite analysis and profiling of two different sets of data results in a plethora of data that is difficult to manage or interpret manually because of their subtle differences. Multivariate statistical methods and pattern‐recognition programs were developed to handle the acquired data and to search for the discriminating features between data acquired from two sample sets, healthy and diseased. Metabolomics have been used in toxicology, plant physiology, and biomedical research. In this paper, we discuss various aspects of metabolomic research including sample collection, handling, storage, requirements for sample analysis, peak alignment, data interpretation using statistical approaches, metabolite identification, and finally recommendations for successful analysis.
Carotenoid production from Chlorococcum littorale in photoautotrophic cultures with downstream supercritical fluid processing
Authors: Ota Masaki , Watanabe Hiromoto , Kato Yoshitaka , Watanabe, Masaru , Sato Yoshiyuki , Smith Richard Lee , Inomata Hiroshi
Published: June 2009

Carotenoid production from highly CO2 tolerant microalga Chlorococcum littorale in photoautotrophic cultures with downstream supercritical fluid processing was studied. Increasing temperature, increasing light intensity and decreasing CO2 and O2 gas concentrations enhanced growth rate under nitrate‐rich conditions. Carotenoid content was insensitive to nitrate concentration, temperature and gas composition, but was greatly promoted by light intensity. Growth rate and carotenoid content had an optimum light intensity of ca. 120 μmol‐photon·m–2s–1. Separation of two sample cultures was studied by applying supercritical fluid extraction with CO2 and 10 mol% ethanol co‐solvent. Extraction yield of carotenoids was 90% with 10 mol% ethanol at 333 K and 30 MPa. Selectivity of a sample with less lipid content (12.9 wt%) was five‐fold higher than that with higher lipid content (29.4 w%).
Profiling of polar metabolites in biological extracts using diamond hydride‐based aqueous normal phase chromatography
Authors: Callahan Damien L. , Souza David De , Bacic Antony , Roessner Ute
Published: June 2009

Highly polar metabolites, such as sugars and most amino acids are not retained by conventional RP LC columns. Without sufficient retention low concentration compounds are not detected due ion suppression and structural isomers are not resolved. In contrast, hydrophilic interaction chromatography (HILIC) and aqueous normal phase chromatography (ANP) retain compounds based on their hydrophilicity and therefore provides a means of separating highly polar compounds. Here, an ANP method based on the diamond hydride stationary phase is presented for profiling biological small molecules by LC. A rapid separation system based upon a fast gradient that delivers reproducible chromatography is presented. Approximately 1000 compounds were reproducibly detected in human urine samples and clear differences between these samples were identified. This chromatography was also applied to xylem fluid from soyabean (Glycine max) plants to which 400 compounds were detected. This method greatly increases the metabolite coverage over RP‐only metabolite profiling in biological samples. We show that both forms of chromatography are necessary for untargeted comprehensive metabolite profiling and that the diamond hydride stationary phase provides a good option for polar metabolite analysis.
Sequestering carbon in soils of arid ecosystems
Authors: Lal R.
Published: June 2009

Recent increase in atmospheric concentration of CO2 and decrease in land‐based sink capacity are attributed to numerous anthropogenic activities including increase in severity and extent of soil degradation and desertification. There is a strong link between desertification and global warming with positive feedback of mutual reinforcement. The biophysical process is also driven by social, economic, political, and cultural factors such as overgrazing by local Bedouin population. Soil carbon (C) sequestration, through conversion to a restorative land use and adoption of recommended management practices, is more in cooler than warmer and higher in wetter than drier climates, and larger in clayey than sandy soils. It ranges from 0 to 200 kg C ha−1 y−1 in soils of semi‐arid climate to 200–500 kg ha−1 y−1 in those of sub‐humid climates. The rates may range from negative to a high of 1500 kg ha−1 y−1. In contrast, the rate of SIC sequestration as secondary carbonates are low and range from 1·5 to 15 kg C ha−1 y−1. In addition to proven technologies (e.g., low stocking rate, afforestaion, soil, and water conservation), there are numerous opportunities for using the modern innovations involving nanotechnology, biotechnology, and information technology. Trading of C credits, through Kyoto's CDM or World Bank's BioCarbon Fund and other mechanisms, opens new opportunities for promoting the use of terrestrial sinks. In this regards, desertified ecosystems in Africa/Asia and elsewhere may benefit through C‐sequestration programs because rehabilitation of degraded lands is an urgent matter of global importance. Copyright © 2009 John Wiley & Sons, Ltd.
Correlation between friction and flow of lubricating greases in a new tribometer device
Authors: Heyer Patrick , Läuger Jörg
Published: June 2009

A tribometer requires speed and normal force control, as well as a torque measurement, to acquire tribological data. An air bearing‐supported rotational rheometer allows the measurement of the same variables, but in a broader range and with better accuracy. This and the intension to measure Stribeck curves, as well as the static friction with one single instrument, led to the idea to design an accessory turning a rheometer into a high‐resolution tribometer based on a ball on pyramid principle. Speed ramp and static friction measurements of oil‐lubricated systems illustrate the performance of the rheo‐tribometer. The flow behaviour of greases is more complex, and extensive rheological and tribological testing was performed on three greases of the American National Lubrication Grease Institute classes 0, 1 and 2 at the temperatures of 25 and −40°C. The influence of temperature could be monitored, and a correlation between rheology and tribology was found. To link the model system with real applications for greases, a ball bearing fixture for the tribological accessory has been designed for which first results are presented. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and Characterization of Low Viscosity Aromatic Hyperbranched Poly(trimellitic anhydride ethylene glycol) Ester Epoxy Resin
Authors: Zhang Daohong , Jia Demin , Chen Sufang
Published: June 2009

From carboxyl‐ended hyperbranched poly(trimellitic anhydride ethylene glycol) ester (HTM) and epichlorohydrin, low viscosity (1 000–1 250 cp) aromatic HTM epoxy resin (HTME) was synthesized. Molar mass of the HTM was calculated from its acid value with a “Recursive Probability Approach”, and its degree of branching (0.63–0.70) was characterized by model compounds and 1H NMR‐minus spectrum technology. HTME has an epoxy equivalent weight of <470 g/mol; it is an ellipsoid‐like molecule with a size of <8.65 nm. This low viscosity novel epoxy resin has important applications in the field of “no‐solvent” coatings.

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Kinetics of Complex Formation between DNA and Cationically Charged Cylindrical Brush Polymers Observed by Stopped Flow Light Scattering
Authors: Kuehn Frauke , Fischer Karl , Schmidt Manfred
Published: June 2009

The complex formation of pUC19 DNA and a cylindrical brush polymer with quaternized poly(vinyl pyridinium) side chains is investigated by stopped flow light scattering (LS). In highly dilute solutions up to two kinetic processes are observable, depending on the mole fraction of anionic charges, xanion. For xanion < 0.2 and xanion > 0.4–0.5 only one kinetic process was identified leading to the largest complexes at xanion = 0.4 well below charge stoichiometry. For 0.2 < xanion < 0.4 two kinetic growth processes were identified: The initially formed complexes on the time scale of a few hundred milliseconds keep growing by an unusual fractal growth process until after several minutes they become stable. This last fractal process does not follow the classical Smoluchowski coagulation theory as monitored by LS up to 90 s after mixing.

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Surface Coatings Based on Polysilsesquioxanes: Solution‐Processible Smooth Hole‐Injection Layers for Optoelectronic Applications
Authors: Kessler Daniel , Lechmann Maria C. , Noh Seunguk , Berger Rüdiger , Lee Changhee , Gutmann Jochen S. , Theato Patrick
Published: June 2009

Optoelectronic devices usually consist of a transparent conductive oxide (TCO) as one electrode. Interfacial engineering between the TCO electrode and the overlying organic layers is an important method for tuning device performance. We introduce poly(methylsilsesquioxane)–poly(N,N‐di‐4‐methylphenylamino styrene) (PMSSQ–PTPA) as a potential hole‐injection layer forming material. Spin‐coating and thermally induced crosslinking resulted in an effective planarization of the anode interface. HOMO level (−5.6 eV) and hole mobility (1 × 10−6 cm2 · Vs−1) of the film on ITO substrates were measured by cyclovoltammetry and time‐of‐flight measurement demonstrating the hole injection capability of the layer. Adhesion and stability for further multilayer built‐up could be demonstrated. Contact angle measurements and tape tests after several solvent treatments proved the outstanding film stability.

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Synthesis of Dendronized Diblock Copolymers via Click Chemistry: The Effect of Dendronization on Phase Separation Behaviour
Authors: Fleischmann Sven , Kiriy Anton , Bocharova Vera , Tock Christian , Komber Hartmut , Voit Brigitte
Published: June 2009

A novel route towards the synthesis of well‐defined linear–dendronized diblock copolymers is reported. Precursor alkyne containing diblock copolymers were modified in a highly efficient cycloaddition reaction with dendritic azides of different generation. The dendronization has been shown to be selective and could be driven to completion under ambient conditions. The phase separation of such dendronized diblock copolymers was investigated in dependence of the generation size being attached. Compared to a linear–linear diblock copolymer as starting material the dendronization yielded in a pronounced phase separation. The nanoscaled features observed in thin films strongly depended on the dendron size and a variety of morphologies could be identified. Hence, the unique combination of controlled radical polymerization and click chemistry allows for the triggering of structured surfaces in the nanometer‐regime.

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Progress in Cellulose Research in the Reflection of the Zellcheming Cellulose Symposium
Authors: Philipp Burkart , Schempp Walter
Published: June 2009

Summary:Within the general topic “Structure and Properties of Cellulose” this presentation covers some principle issues of cellulose research during the recent 50 years and their reflection in the lecture and discussion program of the “Rundgespräch” since 1959. The goal of this “Rundgespräch” was a get together of fundamental research and industrial practice for exchange of information and for cooperation, realizing an interdisciplinary approach of chemistry, physics and technology in cellulosics, supplemented later by environmental problems and aspects of biology and medicine. An especially profitable area of joint activities was found in the analytics of cellulosics, experiencing the entry of modern instrumental methods in cellulose research and the growing relevance of distribution spectra of various structural parameters. With respect to the “renaissance of the viscose process” during the decades after World War II, activities of the “Rundgespräch” were at first centred on the complex sequence of reactions of viscose preparation, including the evaluation of dissolving pulps, and also around the chemistry and the colloid chemistry of filament formation in the spinning process. Further central topics in the following decades were classical and new solvents for cellulose and the states of solution obtained as well as the theoretical meaning and experimental comprehension of cellulose reactivity during chemical processing. Additionally, hemicelluloses were included in the program as well as cellulosic specialties like membranes, cellulose powders, or bead cellulose. Within an integration process of cellulose research into polymer science, composites of cellulose with synthetic polymers gained more relevance in recent years.

Finally, 3 highlights during the 50 years of the “Rundgespräch” are mentioned, i.e.,

a survey of German cellulose research after the re‐unification

a presentation of the stimulating results of the large DFG‐project on molecular and supramolecular structure of cellulosics

this year's program with its really “international flair” and its wide span from the history to actual topics and further to a vision of future development.
The Applicability of Enzymes in Cellulose Ether Analysis
Authors: Adden Roland , Melander Claes , Brinkmalm Gunnar , Knarr Matthias , Engelhardt Jürgen , Mischnick Petra
Published: June 2009

Summary: Six methyl cellulose (MC) samples, one with a DS of 1.32 and five with a DS between 1.83 and 1.88, were degraded with five different enzymes or enzyme preparations containing endoglucanases. The main goal was to investigate whether enzymes could be used for determination of heterogeneity of the substituent distribution along the cellulose chain. To obtain information about the heterogeneity it was necessary to gather information on how the enzymes affect hydrolysis. Monomer composition and methyl distribution in the polymer chain were analyzed after total or partial random hydrolysis and appropriate derivatization by GC and MS, respectively, and used as reference data for the evaluation of the enzymatic hydrolysis. Size exclusion chromatography with multi angle light scattering and refractive index detection (SEC‐MALLS/RI) was used to estimate molar mass distribution of the MCs before and after hydrolysis. Electrospray and matrix assisted laser desorption/ionization (ESI and MALDI) in combination with various MS analyzers were compared with respect to quantification of the degradation products directly and after perdeuteromethylation. Methyl group distribution in the oligomeric fractions and the average DS/DP were calculated from ESI mass spectra. With help of the reference analysis, patterns could be corrected for the unspecific contribution of end groups. By labelling and ESI‐MSn, our knowledge about the tolerance of the enzyme's sub‐sites with respect to the number of methyl groups could be improved. A novel standard addition method in combination with electrospray ionization ion trap mass spectrometry (ESI‐IT MS) was used to determine the amount of formed oligomers.
Reactivity of Dissolving Pulp for Processing Viscose
Authors: Fischer Klaus , Schmidt Ingeborg , Fischer Steffen
Published: June 2009

Summary: Pulp reactivity is a kinetic term and is always connected with a certain derivatization process. The quality and hence the market value of the pulp is determined by such characteristics as α‐ cellulose content, solubility, brightness, ash content, as well as the amount of soluble material in dichloromethane. However, solubility data, especially S18 and S10 values do not characterise dissolving pulp reactivity. These are indicative of pulp solubility and provide some information regarding losses of material during pulp processing. One way by which the pulp reactivity for viscose making can be characterised is the investigation of the mercerisation step. Following the mercerisation kinetics by help of the molecular weight distribution of cellulose II the behaviour especially of the high molecular weight cellulose gives information regarding the accessibility and therefore, about the reactivity of the pulp aside from losses in low molecular weight cellulose. This behaviour will be shown on different pulps and the physicochemical background will be discussed in relation to results obtained from wide angle X‐ray scattering and Raman investigations. The influence of the behaviour of the pulp during mercerising on the viscose process, and the molecular weight distribution of the viscose including the distribution of the xanthogenate groups along the chain was investigated and will also be discussed.
Nanocellulose Materials – Different Cellulose, Different Functionality
Authors: Klemm Dieter , Schumann Dieter , Kramer Friederike , Heßler Nadine , Koth Daniel , Sultanova Barno
Published: June 2009

Summary: Nanocelluloses combine in a very exciting manner important properties of cellulose with amazing features of nano‐scale materials. With a view to the increasing discussion on the potential risks of nanoparticles and nanotechnology to human health and the environment, it is important to point out that the nanocellulose fibers are irreversibly networked in the supramolecular cellulose structure. This contribution assembles the current knowledge in research, development, and application in the field of nanocelluloses through examples. The topics combine selected results on nanocelluloses from bacteria and wood as well as the formation and in situ shaping of cellulose bodies, the coating of materials with nanosized cellulose networks/supports, and the preparation of nanocellulose composites as well as the use of bacterial cellulose as novel type of medical implants.
Novel Cellulose Ethers: Synthesis and Structure Characterization of 3‐Mono‐O‐(3′‐hydroxypropyl) Cellulose
Authors: Schumann Kristin , Pfeifer Annett , Heinze Thomas
Published: June 2009

Summary: The synthesis of 3‐mono‐O‐(3′‐hydroxypropyl) cellulose via 3‐mono‐O‐allyl‐2,6‐di‐O‐thexyldimethylsilyl cellulose was studied. Conversion of the double bond with 9‐borabicyclo[3.3.1]nonane and subsequent alkaline oxidation lead to the 3′‐hydroxypropyl group. Finally, the treatment with tetrabutylammonium fluoride trihydrate yields the complete cleavage of the protecting groups. The structure of the polymer was confirmed by one‐ and two dimensional NMR spectroscopic techniques. 3‐mono‐O‐(3′‐hydroxypropyl) cellulose is soluble in water and aprotic‐dipolar organic media.
Regioselectively Oxidized Cellulose Ethers
Authors: Yin Xueqiong , Koschella Andreas , Heinze Thomas
Published: June 2009

Summary: 3‐Mono‐O‐(2‐methoxyethyl) cellulose (MEC) was selectively oxidized with 2,2,6,6‐tetramethyl‐1‐piperidinyloxy radical (TEMPO)/NaBr/ NaOCl. According to 1D and 2D NMR measurements, the primary hydroxyl group was completely oxidized without affecting the secondary one at position 2. Size‐exclusion chromatography revealed high tendency of 3‐mono‐O‐(2‐methoxyethyl)‐6‐carboxyl cellulose (MECO) to aggregate. Viscosity measurement and gelation of MECO upon interaction with chitosan and Cu2+ ions confirmed the introduction of anionic ions into the polymer backbone. Both MEC and MECO expressed the property of surface activity hence decreasing the surface tension of water (72 mN/m), being 45.0 and 56.8 mN/m, respectively.
Application of Modified Bead Cellulose as a Carrier of Active Ingredients
Authors: Volkert Bert , Wolf Bertram , Fischer Steffen , Li Ning , Lou Chenhua
Published: June 2009

Summary: A new kind of very fine disperse porous bead cellulose is modified by chemical treatments to 2,3‐dialdehyde cellulose, carboxymethyl and dihydrogenphosphate cellulose. Model drugs like benzocaine and prazosin are coupled to these modified bead celluloses by covalent and ionic linkage, respectively and compressed to tablets. Compression mixtures with low loaded benzocaine conjugates release with medium rate. Linkage of prazosin cation to the anionic derivatives of bead cellulose leads to fast release of poor soluble ionic drug.
The affect of the base rate on the extreme dependency score
Authors: Primo Cristina , Ghelli Anna
Published: June 2009

The Extreme Dependency Score (EDS) has been introduced in the verification of rare events because it does not vanish as other standard scores do. The EDS can be written as a function of the base rate and the hit rate. This paper analyses its dependency on the base rate. It is also shown how the score encourages hedging. Guidelines are provided to make proper use of the EDS when verifying the performance of a forecasting system. Copyright © 2009 Royal Meteorological Society
NMR quantification of trace components in complex matrices by band‐selective excitation with adiabatic pulses
Authors: Rastrelli Federico , Schievano Elisabetta , Bagno Alessandro , Mammi Stefano
Published: June 2009

The use of band‐selective excitation with adiabatic pulses to rapidly obtain NMR spectra of trace components in the presence of strong signals is described, along with qualitative and quantitative examples from food matrices like olive oil and honey. Copyright © 2009 John Wiley & Sons, Ltd.
Aurora kinase B modulates chromosome alignment in mouse oocytes
Authors: Shuda Kristy , Schindler Karen , Ma Jun , Schultz Richard M. , Donovan Peter J.
Published: June 2009

The elevated incidence of aneuploidy in human oocytes warrants study of the molecular mechanisms regulating proper chromosome segregation. The Aurora kinases are a well‐conserved family of serine/threonine kinases that are involved in proper chromosome segregation during mitosis and meiosis. Here we report the expression and localization of all three Aurora kinase homologs, AURKA, AURKB, and AURKC, during meiotic maturation of mouse oocytes. AURKA, the most abundantly expressed homolog, localizes to the spindle poles during meiosis I (MI) and meiosis II (MII), whereas AURKB is concentrated at kinetochores, specifically at metaphase of MI (Met I). The germ cell‐specific homolog, AURKC, is found along the entire length of chromosomes during both meiotic divisions. Maturing oocytes in the presence of the small molecule pan‐Aurora kinase inhibitor, ZM447439 results in defects in meiotic progression and chromosome alignment at both Met I and Met II. Over‐expression of AURKB, but not AURKA or AURKC, rescues the chromosome alignment defect suggesting that AURKB is the primary Aurora kinase responsible for regulating chromosome dynamics during meiosis in mouse oocytes. Mol. Reprod. Dev. 76: 1094–1105, 2009. © 2009 Wiley‐Liss, Inc.
Evidence for in vivo macrophage mediated tumor uptake of paramagnetic/fluorescent liposomes
Authors: Castelli Daniela Delli , Terreno Enzo , Cabella Claudia , Chaabane Linda , Lanzardo Stefania , Tei Lorenzo , Visigalli Massimo , Aime Silvio
Published: June 2009

Dysprosium (Dy)‐loaded liposomes act as excellent T2‐susceptibility agents at high magnetic field strength. The R2‐enhancement increases with the size of the liposomes and the concentration of entrapped paramagnetic metal complexes. Neuro‐2a tumor cells are readily labeled when Dy‐loaded liposomes, suitably functionalized with glutamine residues (Gln), are added to the culture medium as glutamine receptors are highly expressed in such proliferating tumor cells. By using fluorescent liposomes doped with fluorescent dyes (either incorporated in the membrane or included in the inner cavity), confocal microscopy experiments showed that targeted liposomes are taken up much more avidly than non‐targeted vesicles. In vivo studies showed that glutamine‐functionalized and non‐functionalized liposomes accumulate in the tumor region to a similar extent. Confocal images of the excised tumor showed extensive co‐localization of liposomes and macrophages in both cases. It is suggested that the loss of tumor specificity, shown by Gln‐functionalized liposomes in vivo, has to be associated with the efficient removal of liposomes operated by the RES (reticulo endoplasmatic system) or tumor associated macrophages. Copyright © 2009 John Wiley & Sons, Ltd.
Well‐conditioned matrices for numerical treatment of Fredholm integral equations of the second kind
Authors: Mastroianni Giuseppe , Milovanović Gradimir V.
Published: June 2009

In the cases A=[−1, 1] and A=[0,+∞), with \documentclass{article}\footskip=0pc\pagestyle{empty}\begin{document}$w(x)=(1-x)^{\alpha}(1+x)^{\beta},\,\alpha,\beta{>}-1,\,{\rm{and}}\,w(x)=x^{\alpha}e^{{-x}^{\beta}},\,\alpha{>}-1,\,\beta{>}\frac{1}{2}$\end{document}, respectively, in this paper we consider the corresponding Fredholm integral equations of the second kind

in the spaces of continuous functions equipped with certain uniform weighted norms. Assuming the continuity of the kernel k(x,y) we use Nyström methods and prove the stability, the convergence and the well conditioning of the corresponding matrices. The last property is derived only from the continuity of the kernel and not from its special form. Error estimates and numerical tests are also included. Copyright © 2009 John Wiley & Sons, Ltd.
Benchmarking the fundraising performance of UK charities
Authors: Aldrich Tobin
Published: June 2009

The cost of fundraising and its effectiveness are issues of increasing importance in the UK nonprofit sector. Measuring fundraising effectiveness properly is critical to organisations on two fronts. From a financial stewardship perspective, charities need to ensure that their fundraising is as efficient as possible. From a public relations perspective they need to be able to demonstrate this to donors and our other stakeholders. There are many problems to be overcome in objectively judging a charity's performance relative to other nonprofit organisations. There are significant methodological barriers to be overcome to produce valid and meaningful comparisons. The well established Fundratios study shows that it is feasible to construct a methodology for robust benchmarking underpinned by good quality data which charities can use as a tool to inform the management of their fundraising activities.

Copyright © 2009 John Wiley & Sons, Ltd.
Congenital scoliosis: possible causes and consequences in a skeleton from Nubia
Authors: Kilgore Lynn , Van Gerven Dennis
Published: June 2009

Reports of congenital scoliosis (CS) are rare in the literature of paleopathology. This study details severe CS in the complete, well preserved skeleton of an adult male, dated to AD 550–800, from the Sudanese site of Kulubnarti. This skeleton, designated as S‐16, is the most complete archaeologically derived example of CS to be documented. Copyright © 2009 John Wiley & Sons, Ltd.
Rotational molding cycle time reduction using a combination of physical techniques
Authors: Abdullah M.Z. , Bickerton S. , Bhattacharyya D. , Crawford R.J. , Harkin‐Jones E.
Published: June 2009

Rotational molding is a process used to manufacture hollow plastic products, and has been heralded as a molding method with great potential. Reduction of cycle times is an important issue for the rotational molding industry, addressing a significant disadvantage of the process. Previous attempts to reduce cycle times have addressed surface enhanced molds, internal pressure, internal cooling, water spray cooling, and higher oven air flow rates within the existing process. This article explores the potential benefits of these cycle time reduction techniques, and combinations of them. Recommendations on a best practice combination are made, based on experimental observations and resulting product quality. Applying the proposed molding conditions (i.e., a combination of surface‐enhanced molds, higher oven flow rates, internal mold pressure, and water spray cooling), cycle time reductions of up to 70% were achieved. Such savings are very significant, inviting the rotomolding community to incorporate these techniques efficiently in an industrial setting. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers