bluuebunny/crossref_metadata_2025 huggingface dataset:
Controls of carbon dioxide concentrations and fluxes above central London
Authors: Helfter C. , Famulari D. , Phillips G. J. , Barlow J. F. , Wood C. R. , Grimmond C. S. B. , Nemitz E.
Published: October 2010

Abstract. Eddy-covariance measurements of carbon dioxide fluxes were taken semi-continuously between October 2006 and May 2008 at 190 m height in central London (UK) to quantify emissions and study their controls. Inner London, with a population of 8.2 million (~5000 inhabitants per km2) is heavily built up with 8% vegetation cover within the central boroughs. CO2 emissions were found to be mainly controlled by fossil fuel combustion (e.g. traffic, commercial and domestic heating). The measurement period allowed investigation of both diurnal patterns and seasonal trends. Diurnal averages of CO2 fluxes were found to be highly correlated to traffic. However changes in heating-related natural gas consumption and, to a lesser extent, photosynthetic activity that controlled the seasonal variability. Despite measurements being taken at ca. 22 times the mean building height, coupling with street level was adequate, especially during daytime. Night-time saw a higher occurrence of stable or neutral stratification, especially in autumn and winter, which resulted in data loss in post-processing. No significant difference was found between the annual estimate of net exchange of CO2 for the expected measurement footprint and the values derived from the National Atmospheric Emissions Inventory (NAEI), with daytime fluxes differing by only 3%. This agreement with NAEI data also supported the use of the simple flux footprint model which was applied to the London site; this also suggests that individual roughness elements did not significantly affect the measurements due to the large ratio of measurement height to mean building height.
Chemical composition and mixing-state of ice residuals sampled within mixed phase clouds
Authors: Ebert M. , Worringen A. , Benker N. , Mertes S. , Weingartner E. , Weinbruch S.
Published: October 2010

Abstract. During an intensive campaign at the high alpine research station Jungfraujoch, Switzerland, in February/March 2006 ice particle residuals within mixed-phase clouds were sampled using the Ice-counterflow virtual impactor (Ice-CVI). Size, morphology, chemical composition, mineralogy and mixing state of the ice residual and the interstitial (i.e., non-activated) aerosol particles were analyzed by scanning and transmission electron microscopy. Ice nuclei (IN) were identified from the significant enrichment of particle groups in the ice residual (IR) samples relative to the interstitial aerosol. In terms of number lead-bearing particles are enriched by a factor of approximately 25, complex internal mixtures with silicates or metal oxides as major components by a factor of 11, and mixtures of secondary aerosol and soot (C-O-S particles) by a factor of 2. Other particle groups (sulfates, sea salt, Ca-rich particles, external silicates) observed in the ice-residual samples cannot be assigned unambiguously as IN. Between 9 and 24% of all IR are Pb-bearing particles. Pb was found as major component in around 10% of these particles (PbO, PbCl2). In the other particles, Pb was found as some 100 nm sized agglomerates consisting of 3–8 nm sized primary particles (PbS, elemental Pb). C-O-S particles are present in the IR at an abundance of 17–27%. The soot component within these particles is strongly aged. Complex internal mixtures occur in the IR at an abundance of 9–15%. Most IN identified at the Jungfraujoch station are internal mixtures containing anthropogenic components (either as main or minor constituent), and it is concluded that admixture of the anthropogenic component is responsible for the increased IN efficiency within mixed phase clouds. The mixing state appears to be a key parameter for the ice nucleation behaviour that cannot be predicted from the separate components contained within the individual particles.
Current status of the ability of the GEMS/MACC models to reproduce the tropospheric CO vertical distribution as measured by MOZAIC
Authors: Elguindi N. , Clark H. , Ordóñez C. , Thouret V. , Flemming J. , Stein O. , Huijnen V. , Moinat P. , Inness A. , Peuch V.-H. , Stohl A. , Turquety S. , Athier G. , Cammas J.-P. , Schultz M.
Published: October 2010

Abstract. Vertical profiles of CO taken from the MOZAIC aircraft database are used to globally evaluate the performance of the GEMS/MACC models, including the ECMWF-Integrated Forecasting System (IFS) model coupled to the CTM MOZART-3 with 4DVAR data assimilation for the year 2004. This study provides a unique opportunity to compare the performance of three offline CTMs (MOZART-3, MOCAGE and TM5) driven by the same meteorology as well as one coupled atmosphere/CTM model run with data assimilation, enabling us to assess the potential gain brought by the combination of online transport and the 4DVAR chemical satellite data assimilation. First we present a global analysis of observed CO seasonal averages and interannual variability for the years 2002–2007. Results show that despite the intense boreal forest fires that occurred during the summer in Alaska and Canada, the year 2004 had comparably lower tropospheric CO concentrations. Next we present a validation of CO estimates produced by the MACC models for 2004, including an assessment of their ability to transport pollutants originating from the Alaskan/Canadian wildfires. In general, all the models tend to underestimate CO. The coupled model and the CTMs perform best in Europe and the US where biases range from 0 to -25% in the free troposphere and from 0 to -50% in the surface and boundary layers (BL). Using the 4DVAR technique to assimilate MOPITT V4 CO significantly reduces biases by up to 50% in most regions. However none of the models, even the IFS-MOZART-3 coupled model with assimilation, are able to reproduce well the CO plumes originating from the Alaskan/Canadian wildfires at downwind locations in the eastern US and Europe. Sensitivity tests reveal that deficiencies in the fire emissions inventory and injection height play a role.
Optimal operation of a multipurpose multireservoir system in the Eastern Nile River Basin
Authors: Goor Q. , Halleux C. , Mohamed Y. , Tilmant A.
Published: October 2010

Abstract. The upper Blue Nile River Basin in Ethiopia is a largely untapped resource despite its huge potential for hydropower generation and irrigated agriculture. Controversies exist as to whether the numerous infrastructural development projects that are on the drawing board in Ethiopia will generate positive or negative externalities downstream in Sudan and Egypt. This study attempts at (1) examining the (re-)operation of infrastructures, in particular the proposed reservoirs in Ethiopia and the High Aswan Dam and (2) assessing the economic benefits and costs associated with the storage infrastructures in Ethiopia and their spatial and temporal distribution. To achieve this, a basin-wide integrated hydro-economic model has been developed. The model integrates essential hydrologic, economic and institutional components of the river basin in order to explore both the hydrologic and economic consequences of various policy options and planned infrastructural projects. Unlike most of the deterministic economic-hydrologic models reported in the literature, a stochastic programming formulation has been adopted in order to: (i) understand the effect of the hydrologic uncertainty on management decisions, (ii) determine allocation policies that naturally hedge against the hydrological risk, and (iii) assess the relevant risk indicators. The study reveals that the development of four mega dams in the upper part of the Blue Nile Basin would change the drawdown refill cycle of the High Aswan Dam. Should the operation of the reservoirs be coordinated, they would enable an average annual saving of at least 2.5 billion m3 through reduced evaporation losses from the Lake Nasser. Moreover, the new reservoirs (Karadobi, Beko-Abo, Mandaya and Border) in Ethiopia would have significant positive impacts on hydropower generation and irrigation in Ethiopia and Sudan: at the basin scale, the annual energy generation is boosted by 38.5 TWh amongst which 14.2 TWh due to storage. Moreover, the regulation capacity of the above mentioned reservoirs would enable an increase of the Sudanese irrigated area by 5.5%.
Generalized versus Non-Generalized Neural Network model for multi-lead inflow forecasting at Aswan High Dam
Authors: El-Shafie A. , Noureldin A.
Published: October 2010

Abstract. Artificial Neural Networks (ANN) have been found efficient, particularly in problems where characteristics of the processes are stochastic and difficult to describe using explicit mathematical models. However, time series prediction based on ANN algorithms is fundamentally difficult and faces problems. One of the major shortcomings is the over-fitting while training session and occurs when a ANN loses its generalization. In this research, Generalized Neural Network (GNN) model is developed to overcome the drawbacks of conventional forecasting techniques. Using GNN helped avoid over-fitting of training data which was observed as a limitation of classical ANN models. Real inflow data collected over the last 130 years at Lake Nasser was used to train, test and validate the proposed model. Results show that the proposed GNN model outperforms Non-Generalized Neural Network and conventional auto-regressive models and it could provide accurate inflow forecasting.
Wavelet analysis of the seismograms for tsunami warning
Authors: Chamoli A. , Swaroopa Rani V. , Srivastava K. , Srinagesh D. , Dimri V. P.
Published: October 2010

Abstract. The complexity in the tsunami phenomenon makes the available warning systems not much effective in the practical situations. The problem arises due to the time lapsed in the data transfer, processing and modeling. The modeling and simulation needs the input fault geometry and mechanism of the earthquake. The estimation of these parameters and other aprior information increases the utilized time for making any warning. Here, the wavelet analysis is used to identify the tsunamigenesis of an earthquake. The frequency content of the seismogram in time scale domain is examined using wavelet transform. The energy content in high frequencies is calculated and gives a threshold for tsunami warnings. Only first few minutes of the seismograms of the earthquake events are used for quick estimation. The results for the earthquake events of Andaman Sumatra region and other historic events are promising.
Study of Plastic Deformation in Hexagonal Metals by Interrupted In‐Situ EBSD Measurement
Authors: Bao Lei , Lecomte Jean‐Sébastien , Schuman Christophe , Philippe Marie‐Jeanne , Zhao Xiang , Esling Claude
Published: October 2010

The present work was undertaken to provide information, lacking in the literature, on the lattice rotation, and the role of twinning during cold rolling of commercial purity titanium (T40). The proposed method consists of determining the individual rotation of the grains induced by low to intermediate deformation (up to 30% in thickness reduction) and following the rotation field using electron backscattered diffraction (EBSD) measurements in a high resolution FEG SEM at different steps of deformation (10 and 20%). We have especially studied the formation, the evolution, and the role of mechanical twins. According to the former research, during deformation at room temperature, three different types of twin systems were activated: ${\left\{ {10\overline {1} 2} \right\}}$ tensile twinning, ${\left\{ {11\overline {2} 2} \right\}}$ compression twinning, and – to a small extent – ${\left\{ {11\overline {2} 1} \right\}}$ tensile twinning depending on the grain orientation. Secondary twins (often ${\left\{ {10\overline {1} 2} \right\}}$ within ${\left\{ {11\overline {2} 2} \right\}}$ twins) were activated in the grains oriented favorably for this secondary twinning. This resulted in a heterogeneous microstructure in which grains were refined in some areas. It also induced reorientation of the c‐axes to stable orientations. No twins of higher order than the second order twins could be found. The rotation flow field was measured by following the rotation of 800 grains. It was possible to determine the individual grains rotations as well as the average flow field. For grains having twinned parts, the lattice rotation of the matrix is similar to that of the grains having a similar crystallographic orientation but without any twins. Twins form in grains having specific orientations with respect to the macroscopic stress field; they can grow in the grain with increasing strain and may consume almost the whole matrix.
A methyltitanocene complex of schisandrol A with high efficacy against multi‐drug resistant cervix and breast carcinoma cells
Authors: Gmeiner Alexander , Effenberger‐Neidnicht Katharina , Zoldáková Miroslava , Schobert Rainer
Published: October 2010

The objective of this work was to combine the ABC‐transporter inhibition characteristic of esters of the Schisandra sphenantera metabolite schisandrol A with the growth inhibitory and anti‐migratory effects typical of titanium complexes. To this end dimethyltitanocene, (h5‐C5H5)2Ti(CH3)2, was reacted with the vicinal diol schisandrol A to afford the schisandroxy(methyl)titanocene (1) as a stable water‐soluble solid. In MTT assays against seven tumor cell lines it proved distinctly more cytotoxic than schisandrol A or dimethyltitanocene or combinations of these. It reached single‐digit micromolar IC50(72 h) values against cells of leukemia HL‐60, melanoma 518A2 and also resistant cervix carcinoma KB‐V1/vbl and resistant breast carcinoma MCF‐7/topo. Non‐malignant fibroblasts were virtually insensitive to it [IC50 (72 h) > 50 µM]. In addition, the new complex inhibited the p‐gp drug transporters of KB‐V1/vbl cells and prevented a regrowth and closure of scratch wounds in cancer cell cultures (‘wound‐healing’ assay) when applied in concentrations < 1 µM, which is an indication of a potential anti‐migratory and anti‐invasive activity in solid tumors. Copyright © 2010 John Wiley & Sons, Ltd.
Agency satisfaction with electronic record management systems: A large‐scale survey
Authors: Hu Paul Jen‐Hwa , Hsu Fang‐Ming , Hu Han‐fen , Chen Hsunchun
Published: October 2010

We investigated agency satisfaction with an electronic record management system (ERMS) that supports the electronic creation, archival, processing, transmittal, and sharing of records (documents) among autonomous government agencies. A factor model, explaining agency satisfaction with ERMS functionalities, offers hypotheses, which we tested empirically with a large‐scale survey that involved more than 1,600 government agencies in Taiwan. The data showed a good fit to our model and supported all the hypotheses. Overall, agency satisfaction with ERMS functionalities appears jointly determined by regulatory compliance, job relevance, and satisfaction with support services. Among the determinants we studied, agency satisfaction with support services seems the strongest predictor of agency satisfaction with ERMS functionalities. Regulatory compliance also has important influences on agency satisfaction with ERMS, through its influence on job relevance and satisfaction with support services. Further analyses showed that satisfaction with support services partially mediated the impact of regulatory compliance on satisfaction with ERMS functionalities, and job relevance partially mediated the influence of regulatory compliance on satisfaction with ERMS functionalities. Our findings have important implications for research and practice, which we also discuss.
Self‐citations that contribute to the journal impact factor: An investment‐benefit‐yield analysis
Authors: Campanario Juan Miguel
Published: October 2010

The variables investment, benefit, and yield were defined to study the influence of journal self‐citations on the impact factor. Investment represents the share of journal self‐citations that contribute to the impact factor. Benefit is defined as the ratio of journal impact factor including self‐citations to journal impact factor without self‐citations. Yield is the relationship between benefit and investment. I selected all journals included in 2008 in the Science Citation Index version of Journal Citation Reports. After deleting 482 records for reasons to be explained, I used a final set of 6,138 journals to study the distribution of the variables defined above. The distribution of benefit differed from the distribution of investment and yield. The top 20‐ranked journals were not the same for all three variables. The yield of self‐citations on the journal impact factor was, in general, very modest.
Exakte U‐Werte von Stahlbeton‐Sandwichelementen
Authors: Willems Wolfgang , Hellinger Georg
Published: October 2010

Zur genauen Ermittlung der Wärmeverluste über die Hüllfläche eines Gebäudes unter stationären Randbedingungen ist — neben anderen Kennwerten — die möglichst exakte Bestimmung der Wärmedurchgangskoeffizienten (U‐Werte) der Fassadenflächen notwendig. Für Fassaden aus Stahlbeton‐Sandwichelementen ist der U‐Wert dabei aus den homogenen Einzelschichten in Verbindung mit den zusätzlichen Wärmeverlusten infolge der systembedingt vorhandenen Anker‐ und Fugensysteme zu bestimmen. üblicherweise werden dazu vereinfacht Pauschalzuschläge angenommen, die zwar das Berechnungsverfahren deutlich vereinfachen, jedoch zu verfälschten Ergebnissen und in der Regel darüber hinaus auch zu ökonomisch ungünstigen Ergebnisse führen. Vor diesem Hintergrund wird im Folgenden ein praxistaugliches Berechnungsverfahren vorgestellt, das die genaue Erfassung der Wärmeverluste aus Anker‐ und Fugensystemen sowohl für individuelle Elementkonfigurationen als auch für beliebig gestaltete Fassaden ermöglicht und damit zu exakten U‐Werten führt.

Precise U‐values of precast concrete sandwich panels. For the exact determination of the heat losses over the building envelope with static boundary conditions it is necessary to determine — besides other parameters — the thermal transmittance (U‐value) of the exterior walls as accurate as possible. The U‐value of precast concrete sandwich panels is quantified on the one hand out of the homogeneous layering of the three sandwich components and on the other hand out of the additional thermal losses of different anchor and joint systems. Usually simplified additions are assumed, which obviously simplify the computation method but generally lead to economically unfavorable results. With this in mind, a practice‐suited computation method is presented which enables the exact examination of additional heat losses for anchor and joint systems for individual element configurations as well as the whole facade system and therefore leads to accurate U‐values.
Einflussparameter auf Heizwärmebedarf und Kühlbedarf von Gebäuden in verschiedenen Berechnungsmethoden von EN ISO 13790
Authors: Gratzl‐Michlmair Markus , Heimrath Richard , Schranzhofer Hermann
Published: October 2010

Für die Berechnung des Energiebedarfs für Heizung und Kühlung können drei Verfahren gleichberechtigt eingesetzt werden: das ausführliche dynamische Simulationsverfahren, das vereinfachte dynamische Stundenverfahren und das quasi‐stationäre Monatsverfahren. Diese verschiedenen Verfahren unterscheiden sich maßgeblich in ihrem Detaillierungsgrad und liefern daher Ergebnisse unterschiedlicher Qualität. Zum Vergleich dieser Ergebnisse werden in der Validierungsnorm EN 15265 die Differenzen der Jahreswerte für die Beurteilung verwendet, die Abweichungen der einzelnen Stunden‐ und Monatswerte bleiben jedoch unberücksichtigt. In diesem Artikel wird daher einerseits dargestellt, wie die Standardabweichung der Einzeldifferenzen in die Qualitätsbewertung der Verfahren aufgenommen werden könnte. Andererseits wird aufgezeigt, welche Auswirkungen die einzelnen Posten der Wärmebilanz auf die Qualität der Ergebnisse haben.

Influencing parameters on calculated heating and cooling energy demand in buildings in accordance to various methods of EN ISO 13790. For calculation of energy use for space heating and cooling three methods can be deployed: detailed simulation method, simplified hourly method and simplified monthly method. The different methods differ significantly in terms of level of detail and therefore also in the quality of their results. For the comparison of the results of different models a standard for validation was established, which evaluates the quality of the models based on differences of the annual sums of energy use for heating and cooling. Differences of hourly or monthly values do not influence the validation. This article shows, how mean value and standard deviation can be integrated into the validation method. Furthermore it describes the influence of the elements of the heat balance on the quality of the results.
Optimierung der thermischen Behaglichkeit im Bestand
Authors: Peters Reinhard , Zerwas Martin , Kempen Thomas , Krause Hans Jürgen
Published: October 2010

In der modernen Welt ist der Mensch es z. B. vom Auto her gewohnt, das Innenraumklima selbst einzustellen, und zwar individuell für Fahrer und Beifahrer. Schwieriger wird dies in unseren Gebäuden, die im Normalfall nur beheizt werden können. Für den Sommer ist die Klimaanlage eine Ausnahme, auch wenn die Verbreitung immer weiter voranschreitet. Kommen mehrere Personen in einem Raum zusammen, ist ein individuelles Wohlfühlklima nicht möglich. Hier kommt es darauf an, den Anteil der unzufriedenen Nutzer möglichst gering zu halten. Im nachfolgenden Beitrag werden die Ursachen für die Beschwerden zweier Großraumbüros untersucht und Vorschläge zur Verbesserung vorgestellt.

Optimisation of thermal comfort in existing buildings. In the modern world people are used to being able to adjust the interior climate, for example with individual settings for car drivers and passengers. The situation is more difficult in buildings which normally only have a heating system without provision for cooling. In moderate climates air‐conditioning systems are an exception, although they are becoming increasingly popular. If several people come together in a room, it is impossible to adjust the conditions to the satisfaction of all occupants. The key is to keep the ratio of dissatisfied users to a minimum. This paper examines the reasons for complaints in two open‐plan offices and offers suggestions for improvements.
Wärme‐ und Feuchtetransport in Holzbauelementen unter freier Bewitterung
Authors: Joščák Matúš , Sonderegger Walter , Niemz Peter
Published: October 2010

Es wurden vergleichende Untersuchungen des Wärme‐ und Feuchtetransportes in unterschiedlichen Holzbaukonstruktionen unter freier Bewitterung durchgeführt. Insgesamt wurden fünf Konstruktionen an Versuchsbauten auf dem Gelände der ETH Zürich getestet. Neben einer verdübelten Massivholzkonstruktion wurden zwei Ständerkonstruktionen und zwei weitere Vollholzkonstruktionen untersucht. Aus den gewonnenen Daten wurden dynamische Parameter der Gebäudehüllen ermittelt. Zusätzlich wurden Messungen an drei realen Bauten (zwei verdübelte Massivholzkonstruktionen, eine Ständerkonstruktion) durchgeführt. Die gemessenen Daten der Versuchsbauten wurden mit den Daten der Messungen an realen Bauten verglichen. Die Ergebnisse zeigen unter anderem, dass die Vollholzkonstruktionen sehr ausgewogene, hygrothermische Eigenschaften aufweisen.

Heat and moisture transfer in wood‐based constructions under natural weathering. In this project comparative measurements of heat and moisture transfer in wood‐based constructions were carried out under natural weathering conditions at the campus of ETH Zurich. Altogether, five different constructions designed as small test buildings were investigated. In the first observation, the solid wood construction connected with wooden dowels — without any further binders is compared to two conventional wood frame constructions with one and two insulation layers. In the second observation, the mentioned solid wood construction is compared to one log construction and one solid wood construction with slotted wood elements. From the data, the dynamic parameters of the heat and moisture transfer of these building envelopes were determined. Additionally, the heat and moisture data of three real used buildings (two solid wood constructions with wooden dowels and one conventional wood frame construction) were measured. These data were compared with the data measured on the small test buildings. The results, inter alia, are showing that the solid wood constructions achieve a good balance in hygrothermal properties.
Die Wanderung der Beuteltiere
Authors: Schmitz Jürgen
Published: October 2010

Aktuelle molekulargenetische Studien ermöglichen eine eindeutige Rekonstruktion der Beuteltierphylogenie. Springende Gene als molekulare Verwandtschaftsmarker weisen erstmals auf einen gemeinsamen Vorfahren aller australischen Beuteltiere hin. Damit ist eine zuverlässige Grundlage geschaffen, um die Evolution und Biogeographie der Beuteltiere zu verstehen.
Baumsterben durch neue Pilze
Authors: Brennicke Axel
Published: October 2010

Bald nach dem Import von Nutzpflanzen aus fernen Ländern folgen auch die Schädlinge und Schmarotzer. Besonders gefährlich sind neue Arten und Abarten des Schleimpilzes Phytophtora.
Zellzählung mittels Neubauer Zählkammer
Authors: Schrödel Andrea
Published: October 2010

Die Bestimmung der Zellzahl von Zellkulturen kann durch Verwendung eines Hämocytometers, wie beispielsweise der Neubauer Zählkammer erfolgen. Die Genauigkeit der Resultate bei der manuellen Zellzählung hängt von der korrekten Handhabung der betreffenden Zählkammer, der Verdünnung der Zellsuspension und der anschließenden Berechnung ab.
Adolf Bückmann, die Biologische Anstalt Helgoland und die marine Fischereibiologie
Authors: Bückmann Detlef
Published: October 2010

Die Biologische Anstalt Helgoland spielt seit ihrer Gründung 1892 eine wichtige Rolle in der deutschen biologischen Forschung und Lehre. Ihre Geschichte und ihr Wiederaufbau nach dem Kriege sind eng verbunden mit dem Namen des Fischereibiologen Adolf Bückmann – dem Vater des Verfassers dieses Artikels. Detlef Bückmann ist selbst Biologe und ehemaliger Rektor der Universität Ulm.
Effect of protein and solution properties on the donnan effect during the ultrafiltration of proteins
Authors: Bolton Glen R. , Boesch Austin W. , Basha Jonida , LaCasse Daniel P. , Kelley Brian D. , Acharya Hari
Published: October 2010

Formulation of protein biopharmaceuticals as highly concentrated liquids can improve the drug substance storage and supply chain, improve the target product profile, and allow greater flexibility in dosing methods. The Donnan effect can cause a large offset in pH from the target value established with the diafiltration buffer during the concentration and diafiltration of charged proteins with ultrafiltration membranes. For neutral formulations, the pH will typically increase above the diafiltration buffer pH for basic monoclonal antibodies and decline below the diafiltration buffer pH for acidic Fc‐fusion proteins. In this study, new equations for the Donnan effect during the diafiltration and concentration of proteins in solutions containing monovalent and divalent ions were derived. The new Donnan models obey mass conservation laws, account for the buffering capacity of proteins, and account for protein‐ion binding. Data for the pH offsets of an Fc‐fusion protein and a monoclonal antibody were predicted in both monovalent and divalent buffers using these equations. To compensate for the pH offset caused by the Donnan effect, diafiltration buffers with pH and excipient values offset from the ultrafiltrate pool specifications can be used. The Donnan offset observed during the concentration of an acidic Fc‐fusion protein was mitigated by operating at low temperature. It is important to account for the Donnan effect during preformulation studies. The excipients levels in an ultrafiltration pool may differ from the levels in a protein solution obtained by adding buffers into concentrated protein solutions due to the Donnan effect. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Evidence for existence of venom 5′ nucleotidase in multiple forms through inhibition of concanavalin A
Authors: Dhananjaya B.L. , Gowda T.V. , J.M. D‘Souza Cletus
Published: October 2010

Pharmacologically active 5′ nucleotidase is a ubiquitously distributed enzyme in snake venoms. In this study the effect of concanavalin A (Con‐A) on different snake venoms 5′ nucleotidase activity is tested in order to know the protein nature which will ultimately help in purification of the enzyme with high yield. Con‐A inhibited Naja naja, Naja kauthia, Naja melanoleuca, Naja naja sputatrix, Agistrodon halys blomhoffii, Bothrops asper and Oxyranus scutellas venom 5′ nucleotidase activity at different concentrations. This indicates the presence of glycopart in the protein, thus glycoprotein in nature. Vipera russellii, Vipera plaestenae, Agistrodon contratrix, Bitis orientis, Echis carinatus and Trimeresures malabaricus was not inhibited by Con‐A, indicating absence of glycopart in the protein. This study for the first time shows existence of 5′ nucleotidase in multimeric forms. Copyright © 2010 John Wiley & Sons, Ltd.
Mechanism of the Catalytic Deperoxidation of tert‐Butylhydroperoxide with Cobalt(II) Acetylacetonate
Authors: Turrà Natascia , Neuenschwander Ulrich , Baiker Alfons , Peeters Jozef , Hermans Ive
Published: October 2010

The CoII/CoIII‐induced decomposition of hydroperoxides is an important reaction in many industrial processes and is referred to as deperoxidation. In the first step of the so‐called Haber–Weiss cycle, alkoxyl radicals and CoIIIOH species are generated upon the reaction of the CoII ion with ROOH. The catalytic cycle is closed upon the regeneration of the CoII ion through the reaction of the CoIIIOH species with a second ROOH molecule, thus producing one equivalent of the peroxyl radicals. Herein, the deperoxidation of tert‐butylhydroperoxide by dissolved cobalt(II) acetylacetonate is studied by using UV/Vis spectroscopy in situ with a noninteracting solvent, namely, cyclohexane. Kinetic information extracted from experiments, together with quantum‐chemical calculations, led to new mechanistic hypotheses. Even under anaerobic conditions, the Haber–Weiss cycle initiates a radical‐chain destruction of ROOH propagated by both alkoxyl and peroxyl radicals. This chain mechanism rationalizes the high deperoxidation rates, which are directly proportional to the cobalt concentration up to approximately 75 μM at 333 K. However, at higher cobalt concentrations, a remarkable decrease of the rate is observed. The hypothesis put forward herein is that this remarkable autoinhibition effect could be explained by the hitherto overlooked chain termination of two CoIIIOH species. The direct competition between the first‐order Haber–Weiss initiation and the second‐order termination can indeed explain this peculiar kinetic behavior of this homogeneous deperoxidation system.
Photochemical Synthesis of Intensely Luminescent Isocyano Rhenium(I) Complexes with Readily Tunable Structural Features
Authors: Ko Chi‐Chiu , Lo Larry Tso‐Lun , Ng Chi‐On , Yiu Shek‐Man
Published: October 2010

A new class of readily tunable isocyano rhenium(I) diimine luminophores, cis,cis‐[Re(CO)2(CNR)2‐ (NN)]+ (R=2,4,6‐Cl3C6H2, 4‐ClC6H4, 4‐Br‐2,6‐(CH3)2C6H2, 2,6‐(CH3)2C6H3, 4‐[(CH3)2N]C6H4, 4‐(C6H5)C6H4, 4‐nBuC6H4, tBu), has been synthesized in high yield by a highly selective photochemical substitution reaction. These complexes were characterized by 1H NMR and IR spectroscopy, mass spectrometry, and elemental analysis. The X‐ray crystal structures of one of the complexes and one of the precursor complexes for the photosubstitution reaction were also determined. As the isocyanide ligands are readily tunable, complexes with excellent solubility in benzene or other nonpolar solvents could be designed through slight modification of the isocyanide ligands with a short nBu substituent. With the characteristic strong infrared absorptions of the carbonyl (CO) and isocyanide (CN) stretches as well as the high solubility of the reactant and product in benzene, which is the solvent for the photoreaction, the photosubstitution reaction of [Re(CO)3(nBuC6H4NC)2Br] with 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine was also studied by in situ IR spectroscopy. The photophysical and electrochemical properties of these complexes were also investigated. Except for the complex with [(CH3)2N]C6H4NC ligands, all complexes displayed intense luminescence with quantum yields of up to 0.37 in degassed CH2Cl2 solution at room temperature. These emissions were assigned as the phosphorescence derived from the metal‐to‐ligand charge transfer [dπ(Re)→π*(NN)] excited state. The emissive excited states of these complexes have also been characterized by transient absorption spectroscopic studies. The capability of tuning the emissive excited‐state energy through the modification of the isocyanide ligands could be reflected by the significant shifting of the phosphorescence from 530 to 620 nm with the same phenanthroline ligand.
Methylation of the candidate biomarker TCF21 is very frequent across a spectrum of early‐stage nonsmall cell lung cancers
Authors: Richards Kristy L. , Zhang Baili , Sun Menghong , Dong Wenli , Churchill Jennifer , Bachinski Linda L. , Wilson Charmaine D. , Baggerly Keith A. , Yin Guosheng , Hayes D. Neil , Wistuba Ignacio I. , Krahe Ralf
Published: October 2010

BACKGROUND:

The transcription factor TCF21 is involved in mesenchymal‐to‐epithelial differentiation and was shown to be aberrantly hypermethylated in lung and head and neck cancers. Because of its reported high frequency of hypermethylation in lung cancer, further characterization of the stages and types of nonsmall cell lung cancer (NSCLC) that are hypermethylated and the frequency of hypermethylation and associated “second hits” were assessed.

METHODS:

TCF21 promoter hypermethylation in 105 NSCLC including various stages and histologies in smokers and nonsmokers was determined. In addition, TCF21 loss of heterozygosity and mutational status were examined. Twenty‐two cancer cell lines from varied tissue origins were also assayed. The NSCLC results were validated and expanded by examining TCF21 immunohistochemical expression on a tissue microarray containing 300 NSCLC cases.

RESULTS:

Overall, 81% of NSCLC samples showed TCF21 promoter hypermethylation, and 84% showed decreased TCF21 protein expression. Multivariate analysis showed that TCF21 expression, although below normal in both histologies, was lower in adenocarcinoma than in squamous cell carcinoma and was not independently correlated with sex, smoking, and EGFR mutation status or with clinical outcome. Cell lines from other cancer types also showed frequent TCF21 promoter hypermethylation.

CONCLUSIONS:

Hypermethylation and decreased expression of TCF21 were tumor specific and very frequent in all NSCLCs, even early‐stage disease, thus making TCF21 a potential candidate methylation biomarker for early‐stage NSCLC screening. TCF21 hypermethylation in a variety of tumor cell lines suggests it may also be a valuable methylation biomarker in other tumor types. Cancer 2011. © 2010 American Cancer Society.
The role of epigenetic transcription repression and DNA methyltransferases in cancer
Authors: Daniel Filipe Ivan , Cherubini Karen , Yurgel Liliane Soares , de Figueiredo Maria Antonia Zancanaro , Salum Fernanda Gonçalves
Published: October 2010

Epigenetic alterations such as DNA methylation have been implicated in the development and progression of various cancers. DNA methylation consists of the reversible addition of a methyl group to the carbon 5 position of cytosine in CpG dinucleotides and is considered essential for normal embryonic development. However, global genomic hypomethylation and aberrant hypermethylation of regulatory regions of tumor suppressor genes have been associated with chromosomal instability and transcription repression, respectively, providing neoplastic cells with a selective advantage. DNA methyltransferases are the enzymes responsible for the addition of methyl groups to CpG dinucleotides, which, together with histone modifiers, initiate the events necessary for transcription repression to occur. It has been demonstrated that increased expression of DNA methyltransferases may contribute to tumor progression through methylation‐mediated gene inactivation in various human cancers. Given their importance, this article reviews the main epigenetic mechanisms for regulating transcription and its implications in cancer development. Cancer 2011. © 2010 American Cancer Society.
Local, regional, and systemic recurrence rates in patients undergoing skin‐sparing mastectomy compared with conventional mastectomy
Authors: Yi Min , Kronowitz Steven J , Meric‐Bernstam Funda , Feig Barry W , Symmans W. Fraser , Lucci Anthony , Ross Merrick I , Babiera Gildy V , Kuerer Henry M , Hunt Kelly K
Published: October 2010

BACKGROUND:

Although the use of SSM is becoming more common, there are few data on long‐term, local‐regional, and distant recurrence rates after treatment. The purpose of this study was to examine the rates of local, regional, and systemic recurrence, and survival in breast cancer patients who underwent skin‐sparing mastectomy (SSM) or conventional mastectomy (CM) at our institution.

METHODS:

Patients with stage 0 to III unilateral breast cancer who underwent total mastectomy at our center from 2000 to 2005 were included in this study. Kaplan‐Meier curves were calculated, and the log‐rank test was used to evaluate the differences between overall and disease‐free survival rates in the 2 groups.

RESULTS:

Of 1810 patients, 799 (44.1%) underwent SSM and 1011 (55.9%) underwent CM. Patients who underwent CM were older (58.3 vs 49.3 years, P<.0001) and were more likely to have stage IIB or III disease (53.0% vs 31.8%, P<.0001). Significantly more patients in the CM group received neoadjuvant chemotherapy and adjuvant radiation therapy (P<.0001). At a median follow‐up of 53 months, 119 patients (6.6%) had local, regional, or systemic recurrences. The local, regional, and systemic recurrence rates did not differ significantly between the SSM and CM groups. After adjusting for clinical TNM stage and age, disease‐free survival rates between the SSM and CM groups did not differ significantly.

CONCLUSIONS:

SSM is an acceptable treatment option for patients who are candidates for immediate breast reconstruction. Local‐regional recurrence rates are similar to those of patients undergoing CM. Cancer 2011. © 2010 American Cancer Society.
A higher degree of methylation of the HPV 16 E6 gene is associated with a lower likelihood of being diagnosed with cervical intraepithelial neoplasia
Authors: Piyathilake Chandrika J. , Macaluso Maurizio , Alvarez Ronald D. , Chen Min , Badiga Suguna , Edberg Jeffrey C. , Partridge Edward E. , Johanning Gary L.
Published: October 2010

BACKGROUND:

Although HPV 16 is the most common HPV genotype associated with cancerous lesions of the cervix, only a fraction of HPV 16 infected women are diagnosed with precancerous lesions of the cervix. Therefore, molecular changes in HPV 16, rather than infections per se, may serve as better screening or diagnostic biomarkers. The purpose of the study was to evaluate whether methylation status of specific regions of the HPV E6 gene promoter and enhancer is independently associated with the likelihood of being diagnosed with higher grades of cervical intraepithelial neoplasia (CIN 2+).

METHODS:

The study included 75 HPV 16‐positive women diagnosed with CIN 2+ or ≤CIN 1. Pyrosequencing technology was applied to quantify methylation at 6 cytosine guanine dinucleotide (CpG) sites of the HPV 16 E6 promoter and enhancer. CIN 2+ (yes/no) was the dependent variable in logistic regression models that specified the degree of methylation of the CpG sites of the HPV 16 E6 gene as the primary independent predictors. All models were adjusted for demographic, lifestyle, known risk factors for cervical cancer, and circulating concentrations of “cancer‐protective” micronutrients.

RESULTS:

The odds of being diagnosed with CIN 2+ were 79% lower when the degree of methylation of the HPV 16 enhancer and promoter sites was ≥9.5% (OR = 0.21; 95% CI, 0.06‐0.79; P = .02).

CONCLUSIONS:

Results suggested that CpG methylation is independently involved in the biology of HPV 16 as well as in the development of higher grades of CIN. Cancer 2011. © 2010 American Cancer Society.
International staging system and metaphase cytogenetic abnormalities in the era of gene expression profiling data in multiple myeloma treated with total therapy 2 and 3 protocols
Authors: Waheed Sarah , Shaughnessy John D. , van Rhee Frits , Alsayed Yazan , Nair Bijay , Anaissie Elias , Szymonifka Jackie , Hoering Antje , Crowley John , Barlogie Bart
Published: October 2010

BACKGROUND:

Myeloma survival varies markedly with International Staging System classification, presence of cytogenetic abnormalities, and, especially, gene expression profiling‐based risk and delTP53 status, whose collective impact has not been examined in the context of specific therapies.

METHODS:

The authors examined overall survival (OS), event‐free survival (EFS), and complete response duration (CRD) in Total Therapy 2 with randomization to a control or thalidomide arm and in Total Therapy 3 with added bortezomib. Among 612 patients with complete data sets, multivariate analyses were used to investigate the relative contributions to OS, EFS, and CRD of International Staging System stage, cytogenetic abnormalities, and gene expression profiling‐derived risk and delTP53 status, in the context of the 3 Total Therapy regimens.

RESULTS:

Whereas gene expression profiling risk segregated outcomes within all 3 International Staging System stages, International Staging System 3 conferred inferior prognosis only in low‐risk myeloma, whereas the grave prognosis of high‐risk disease was International Staging System‐independent. After adjusting for gene expression profiling‐defined high risk and delTP53 in multivariate analysis, International Staging System 3 and cytogenetic abnormalities both retained independent adverse implications for OS, EFS, and CRD. Among the 86% with low‐risk disease, cytogenetic abnormalities and delTP53 both affected all 3 endpoints negatively, whereas the International Staging System 3 effect was limited to OS. Total Therapy 3 improved survival outcomes beyond results obtained with Total Therapy 2.

CONCLUSIONS:

In the genomic era, standard laboratory variables, such as International Staging System stage and presence of cytogenetic abnormalities, continue to impact survival after adjusting for gene expression profiling risk and delTP53 status, providing a basis for stratification in our current practice of gene expression profiling risk‐based treatment assignment.Cancer 2011. © 2010 American Cancer Society.
Racial disparity in death from colorectal cancer
Authors: Fiscella Kevin , Winters Paul , Tancredi Daniel , Hendren Samantha , Franks Peter
Published: October 2010

BACKGROUND:

The reasons blacks have higher mortality rates from colorectal cancer (CRC) than non‐Hispanic whites are not fully understood. Blacks have higher rates of vitamin D deficiency than non‐Hispanic whites, and vitamin D deficiency has been associated with CRC. The authors of this report investigated the association of vitamin D deficiency with excess risk for CRC mortality for blacks in the Third National Health and Nutrition Examination Survey (NHANES III) that was conducted from 1988 to 1994.

METHODS:

The association between serum 25(OH)D levels and CRC mortality and its contribution to elevated risk among blacks were studied using baseline data from NHANES III and CRC mortality data through 2006 from the National Death Index. By using survival models, the adjusted risk of death from CRC for African Americans was examined with and without adjusting for vitamin D deficiency, which was defined as an 25(OH)D level <20 ng/dL.

RESULTS:

Black race (hazard ratio [HR], 2.03; 95% confidence interval [95% CI], 1.04‐3.95), age (HR, 1.12; 95% CI, 1.09‐1.15), not having health insurance (HR, 2.45; 95% CI, 1.12‐5.36), and a history of CRC (HR, 7.22; 95% CI, 2.12‐24.6) predicted CRC mortality. When added to the model, vitamin D deficiency was associated significantly with CRC mortality (HR, 2.11; 95% CI, 1.11‐4.00), and the effect of race was decreased (HR, 1.60; 95% CI, 0.87‐2.93); the 40% attenuation was statistically significant (F1,49 = 4.85; P = .03). Similar results were observed when participants who had a history of CRC were excluded from the analysis.

CONCLUSIONS:

The current findings were consistent with the hypothesis that vitamin D deficiency contributes to excess African‐American mortality from CRC. Cancer 2011. © 2010 American Cancer Society.
Underutilization of therapy for hepatocellular carcinoma in the medicare population
Authors: Shah Shimul A. , Smith Jillian K. , Li YouFu , Ng Sing Chau , Carroll James E. , Tseng Jennifer F.
Published: October 2010

BACKGROUND:

The incidence of hepatocellular carcinoma (HCC) is increasing in the United States, and the care of these patients remains highly specialized and complex. Multiple treatment options are available for HCC but their use and effectiveness remain unknown.

METHODS:

Using Surveillance, Epidemiology, and End Results (SEER)‐Medicare linked data, 8730 patients who were diagnosed with HCC between 1991 and 2005 were identified. Therapy included surgical resection (8.7%), liver transplantation (1.4%), ablation (3.6%), or transarterial chemoembolization (16%). Patients who received no or palliative‐only treatment were grouped together (NoTx; 70.3%). Patient, disease, and tumor factors were examined as determinants of therapy.

RESULTS:

HCC is increasing in the Medicare population. The median age at diagnosis was 75.1 years and 73.6% of patients were coded as white, 17.2% as Asian, 8.3% as black, and 0.9% as other race. The rate of therapy increased over time, but only 29.7% of patients overall underwent therapy. In patients with early stage HCC, only 43.1% underwent therapy. In the NoTx group, 49.4% did not have cirrhosis, 36.0% had tumors that measured <5 cm, and 39.8% were diagnosed with stage I or II disease when variables were complete. The use of therapy for all HCC patients increased over time, correlating with a commensurate increase in median survival. In multivariate regression analysis, patients who received any modality of treatment achieved significant benefit compared with the NoTx group (odds ratio, 0.41; 95% confidence interval, 0.39‐0.43).

CONCLUSIONS:

In the Medicare population, HCC patients who received therapy experienced a substantial survival advantage over their nonoperative peers (NoTx). Despite evidence that many patients had favorable biological characteristics, <30% of patients diagnosed with HCC received any treatment. Cancer 2011. © 2010 American Cancer Society.