bluuebunny/crossref_metadata_2025_split huggingface dataset:
Amphiphilic, low molecular weight poly(ethylene imine) derivatives with enhanced stability for efficient pulmonary gene delivery
Authors: Roesler Susanne , Koch Felix P. V. , Schmehl Thomas , Weissmann Norbert , Seeger Werner , Gessler Tobias , Kissel Thomas 
Published: December 2010

AbstractBackgroundPoly(ethylene imine) (PEI) is a widely used transfection reagent for mammalian cells, but in vivo application of PEI 25 kDa is restricted by its toxicity. Low molecular weight (LMW) PEI is less toxic, but also less efficient than its high molecular weight equivalent, and prone to aggregation.MethodA set of polymers was synthesized by coupling poly(ethylene glycol) (PEG) that contained either C16/18‐chains (Cx‐EO) or butyl‐poly(propylene oxide)‐co‐poly(ethylene glycol) (ButPP). Critical micelle concentration (CMC) was determined for copolymers. Polyplexes were characterized by DNA binding ability, polyplex size and aggregation, hemolysis, and cytotoxicity. Transfection efficiency was tested in vitro and in vivo in mouse lungs.ResultsCopolymers formed stable complexes with DNA, and showed enhanced complex stability in isotonic solution for at least 1 h. CMC was determined for Cx‐EO‐PEI 4.7 and 8.3 at 0.0019 and 0.0037 mM, respectively; membrane activity in a haemolysis assay was demonstrated for ButPP‐PEI: both factors possibly enhance endosomal escape effect after PEGylation. IC50 values of all synthesized polymers were in the range 6–33 ng/ml. Transfection efficiency of unmodified LMW‐PEIs was equivalent or better than that of PEI 25 as a result of aggregation in vitro. Cells treated with polyplexes of amphiphilic polymers showed reduced transfection compared to PEI 25. After instillation in mouse lungs, highest transfection efficiency was demonstrated with Cx‐EO copolymer of lowest molecular weight PEI.ConclusionsA new set of polymers with low toxicity and high stability was synthesized, which contains promising candidates for pulmonary gene transfer, as documented by in vivo experiments in mice. Copyright © 2011 John Wiley & Sons, Ltd.
The C‐terminus of the phage λ Orf recombinase is involved in DNA binding
Authors: Curtis Fiona A. , Reed Patricia , Wilson Lindsay A. , Bowers Laura Y. , Yeo Robert P. , Sanderson John M. , Walmsley Adrian R. , Sharples Gary J. 
Published: December 2010

AbstractPhage λ Orf substitutes for the activities of the Escherichia coli RecFOR proteins in vivo and is therefore implicated as a recombination mediator, encouraging the assembly of bacterial RecA onto single‐stranded DNA (ssDNA) coated with SSB. Orf exists as a dimer in solution, associates with E. coli SSB and binds preferentially to ssDNA. To help identify interacting domains we analysed Orf and SSB proteins carrying mutations or truncations in the C‐terminal region. A cluster of acidic residues at the carboxy‐terminus of SSB is known to attract multiple protein partners to assist in DNA replication and repair. In this case an alternative domain must be utilized since Orf association with SSB was unaffected by an SSB113 point mutant (P176S) or removal of the last ten residues (ΔC10). Structurally the Orf C‐terminus consists of a helix with a flexible tail that protrudes from each side of the dimer and could serve as a binding site for either SSB or DNA. Eliminating the six residue flexible tail (ΔC6) or the entire helix (ΔC19) had no significant impact on the Orf–SSB interaction. However, the OrfΔC6 protein exhibited reduced DNA binding, a feature shared by single amino acid substitutions within (W141F) or adjacent (R140A) to this region. The OrfΔC19 mutant bound poorly to DNA and secondary structure analysis in solution revealed that this truncation induces protein misfolding and aggregation. The results show that the carboxy‐terminus of Orf is involved in nucleic acid recognition and also plays an unexpected role in maintaining structural integrity. Copyright © 2010 John Wiley & Sons, Ltd.
Interaction map of the Trypanosoma cruzi ribosomal P protein complex (stalk) and the elongation factor 2
Authors: Smulski Cristian R. , Longhi Silvia A. , Ayub Maximiliano Juri , Edreira Martin M. , Simonetti Leandro , Gómez Karina A. , Basile Joaquín N. , Chaloin Olivier , Hoebeke Johan , Levin Mariano J. 
Published: December 2010

AbstractThe large subunit of the eukaryotic ribosome possesses a long and protruding stalk formed by the ribosomal P proteins. This structure is involved in the translation step of protein synthesis through interaction with the elongation factor 2 (EF‐2). The Trypanosoma cruzi stalk complex is composed of four proteins of about 11 kDa, TcP1α, TcP1β, TcP2α, TcP2β and a fifth TcP0 of about 34 kDa. In a previous work, a yeast two‐hybrid (Y2H) protein–protein interaction map of T. cruzi ribosomal P proteins was generated. In order to gain new insight into the assembly of the stalk, a complete interaction map was generated by surface plasmon resonance (SPR) and the kinetics of each interaction was calculated. All previously detected interactions were confirmed and new interacting pairs were found, such as TcP1β–TcP2α and TcP1β–TcP2β. Moreover P2 but not P1 proteins were able to homo‐oligomerize. In addition, the region comprising amino acids 210–270 on TcP0 was identified as the region interacting with P1/P2 proteins, using Y2H and SPR. The interaction domains on TcP2β were also mapped by SPR identifying two distinct regions. The assembly order of the pentameric complex was assessed by SPR showing the existence of a hierarchy in the association of the different P proteins forming the stalk. Finally, the TcEF‐2 gene was identified, cloned, expressed and refolded. Using SPR analysis we showed that TcEF‐2 bound with similar affinity to the four P1/P2 ribosomal P proteins of T. cruzi but with reduced affinity to TcP0. Copyright © 2010 John Wiley & Sons, Ltd.
Effects of regional warming on extreme monthly low temperatures distribution in China
Authors: Zhou Guohua , Wan Shiquan , Feng Guolin , He Wenping 
Published: December 2010

AbstractUsing generalised Pareto distribution (GPD) function, the regional characteristic of extreme monthly low temperatures (EMLT) distribution during 1960‐2007 in China is studied, and the potential impact of climate warming on EMLT regions in China is analysed. The results show that EMLT space distribution has latitudinal difference in China. Higher‐value EMLT events are likely to happen in northeastern and southwestern China, while EMLT variability and occurrence probability of high‐value EMLT events are less in the Yangtze and Huaihe River basin and the coast of southern China. The study indicates that climate warming impacts EMLT, and EMLT distribution responds to the climate warming over most areas of China. Copyright © 2010 Royal Meteorological Society
A summer weather index in the East Asian pressure field and associated atmospheric circulation and rainfall
Authors: Zhao Ping , Zhu Yani , Zhang Qin 
Published: December 2010

AbstractUsing the daily rainfall from rain gauge stations in China and the daily data from the National Centers for Environmental Prediction‐National Center for Atmospheric Research (NCEP‐NCAR) reanalysis for each year of 1981–2008, a relationship between daily rainfall over the Yangtze‐Huaihe River basin (YHB) and surface pressure over East Asia was statistically investigated and a summer weather index (ISW) was defined from surface pressure for describing the daily variations of the atmospheric circulation and rainfall over the monsoon region of eastern China. The results show that the daily ISW is significantly correlated with the YHB rainy weather during summer. In higher‐ISW days, there is usually more YHB rainfall. This link may be explained by the East Asian atmospheric circulation well. When ISW is higher, a low‐pressure system frequently occurs over the land of southern China and an enhanced ridge appears over the South China Sea (SCS)–subtropical western Pacific region, which strengthens the seaward pressure gradient and southwesterly winds over southern China. Accordingly, the transport of water vapour toward the YHB and the ascending motion over the YHB strengthen remarkably. These variations in the daily atmospheric circulation finally lead to the frequent occurrence of the YHB rainy weather. Thus, ISW can represent the variations of the atmospheric circulation and rainy weather for most of the years of 1981–2008. For some extremely dry years over the YHB, however, ISW does not indicate the local large‐scale rainfall well. This suggests an asymmetric descriptive ability of this index. Copyright © 2010 Royal Meteorological Society
Effects of molecular characteristics of on konjac glucomannan glass transitions of potato amylose, amylopection and their mixtures
Authors: Guo Li , Liang Qin , Du Xianfeng 
Published: December 2010

AbstractBACKGROUND: The purpose of this study was to explore further the functions of konjac glucomannan (KGM) in starch‐based foods. Experiments were carried out using the mixed amylose/amylopectin/KGM system as a model. High‐speed differential scanning calorimetry (hyper‐DSC) with the support of high‐performance size exclusion chromatography (HPSEC) equipped with multi‐angle laser light scattering (MALLS) and differential refractive index (RI), X‐ray diffractometry (XRD) and viscosimetry was used to investigate the effects of KGM on glass transition temperatures (Tgs) of mixtures with different amylose/amylopectin ratios.RESULTS: Hyper‐DSC results showed that the Tgs of amylose, amylopection and their mixtures decreased with increasing concentration of KGM. Based on the molecular characteristics of KGM, HPSEC‐MALLS‐RI, viscosimetry and XRD results showed that the molar masses of KGM ranged from 1.023 × 106 to 1.329 × 106 g mol−1; the root mean square (RMS) radii were distributed from 110.5 to 129.6 nm, and Mw/Mn was 1.017. KGM was a linear molecule with random‐coil conformation in solution and the crystallinity was 0.00%.CONCLUSION: It is suggested that the addition of KGM has plasticizing effects on the structures of amylose and amylopectin, which can increase free volume and molecular movement of amylose and amylopectin chains, resulting in a decrease in their Tgs. Copyright © 2010 Society of Chemical Industry
A Case study: discussion of factors and challenges for urban cultural tourism development
Authors: Wang Suosheng , Yamada Naoko , Brothers Linda 
Published: December 2010

AbstractWith both qualitative and quantitative approaches, this study examined the success factors of cultural tourism development. It discussed reasons why some cities may find it challenging to sustain cultural tourism development. The findings suggested that the lack of advantageous factors may be because all factors were highly related and that one factor's defect in marketing could easily affect the performance of all other factors. The challenge for cultural tourism development in a less competitive destination may be more related to elementary problems such as governmental leadership and funding rather than the important factors emphasized in theoretical models. Copyright © 2010 John Wiley & Sons, Ltd.
Industriechemikalien durch Olefin‐Metathese natürlicher Fettsäureester
Authors: Warwel Siegfried 
Published: December 2010

AbstractÜber Nachwachsende Rohstoffe wird seit einigen Jahren diskutiert: Insbesondere Cellulose, Stärke und Zucker sowie natürliche Öle und Fette könnten die Rohstoffbasis der chemischen Industrie ergänzen und erweitern sowie Anbau‐Alternativen für die Landwirtschaft eröffnen.
Industrielle Wirkstofforschung und Theoretische Chemie
Authors: Egner Ursula , Eckle Emil , Heinrich Nikolaus , Hoyer Georg‐Alexander 
Published: December 2010

AbstractBei der Suche nach neuen Wirkstoffen für Pharmazeutika und Pflanzenschutzmittel müssen immer mehr Verbindungen synthetisiert werden. Wirksam unterstützt werden die Synthesegruppen bei der Wirkstofforschung durch theoretische Chemiker, die vielfältige und zum Teil komplementäre Erfahrungen in diese Kooperation einbringen, z.B. Struktur‐Wirkungs‐Analysen, Molecular Modelling von Proteinen und Rezeptoren, ab initio‐Rechnungen.
Unsere Erde braucht Ideen
Authors: Fiedler Walfgang J. 
Published: December 2010

AbstractUnter diesem Slogan präsentierte die Degussa AG, Frankfurt a.M., am 4. Juni in einer Forschungspressekonferenz am Standort Hanau‐Wolfgang ihre aktuellen Neuentwicklungen aus Forschung und Entwicklung.
GDCh‐Statistik der Chemiestudiengänge 1997
Authors: Schmitz Karin 
Published: December 2010

AbstractDer folgende Bericht faßt die Ergebnisse der jährlichen GDCh‐Erhebung zu den Chemiestudiengängen in Deutschland zusammen und stellt die wichtigsten Daten und Trends aus den Studiengängen Chemie, Biochemie, Lebensmittelchemie und Lehramt Chemie vor. In die Umfrage sind die Chemiestudiengänge der Universitäten und Technischen Hochschulen, der Fachhochschulen und die Diplom l‐Studiengänge der Gesamthochschulen einbezogen. Die vollständigen Ergebnisse der statistischen Erhebungen sind als Broschüre bei der GDCh‐Geschäftsstelle erhältlich.
Neural correlates of motor imagery for elite archers
Authors: Chang Yongmin , Lee Jae‐Jun , Seo Jee‐Hye , Song Hui‐Jin , Kim Yang‐Tae , Lee Hui Joong , Kim Hye Jung , Lee Jongmin , Kim Woojong , Woo Minjung , Kim Jin Gu 
Published: December 2010

AbstractMotor imagery is a mental rehearsal of simple or complex motor acts without overt body movement. It has been proposed that the association between performance and the mental rehearsal period that precedes the voluntary movement is an important point of difference between highly trained athletes and beginners. We compared the activation maps of elite archers and nonarchers during mental rehearsal of archery to test whether the neural correlates of elite archers were more focused and efficiently organised than those of nonarchers. Brain activation was measured using functional MRI in 18 right‐handed elite archers and 18 right‐handed nonarchers. During the active functional MRI imagery task, the participants were instructed to mentally rehearse their archery shooting from a first‐person perspective. The active imagery condition was tested against the nonmotor imagery task as a control condition. The results showed that the premotor and supplementary motor areas, and the inferior frontal region, basal ganglia and cerebellum, were active in nonarchers, whereas elite archers showed activation primarily in the supplementary motor areas. In particular, our result of higher cerebellar activity in nonarchers indicates the increased participation of the cerebellum in nonarchers when learning an unfamiliar archery task. Therefore, the difference in cerebellar activation between archers and nonarchers provides evidence of the expertise effect in the mental rehearsal of archery. In conclusion, the relative economy in the cortical processes of elite archers could contribute to greater consistency in performing the specific challenge in which they are highly practised. Copyright © 2010 John Wiley & Sons, Ltd.
Combined 1H and 31P spectroscopy provides new insights into the pathobiochemistry of brain damage in multiple sclerosis
Authors: Hattingen Elke , Magerkurth Jörg , Pilatus Ulrich , Hübers Annemarie , Wahl Mathias , Ziemann Ulf 
Published: December 2010

Abstract1H MRSI has evolved as an important tool to study the onset and progression of brain damage in multiple sclerosis. Abnormal increases in total creatine, total choline and myoinositol have been noted in multiple sclerosis. However, the pathobiochemical mechanisms related to these changes are still largely unclear. The combination of 1H MRSI and 1H‐decoupled 31P MRSI can specify to what extent phosphorylated components of total creatine and total choline contribute to this increase. Combined 1H and 31P MRSI data were obtained at 3 T in 22 patients with multiple sclerosis and in 23 healthy controls, and aligned with structural MRI to allow for correction for partial volume effects caused by cerebrospinal fluid and lesion load. A significant increase in total creatine was found in multiple sclerosis, and this was attributed to equal changes in the phosphorylated and unphosphorylated components. The concentrations of the putative glial markers total creatine and myoinositol in lesion‐free 1H MRSI voxels correlated with the global lesion load. We conclude that changes in total creatine are not related to altered energy metabolism, but rather indicate gliosis. Together with the increase in myoinositol, total creatine can be considered as a biomarker for disease severity. A significant total choline increase was mainly a result of choline components not visible by 31P MRS. The origin of this residual choline fraction remains to be investigated. Copyright © 2010 John Wiley & Sons, Ltd.
In vivo characterization of the liver fat 1H MR spectrum
Authors: Hamilton Gavin , Yokoo Takeshi , Bydder Mark , Cruite Irene , Schroeder Michael E. , Sirlin Claude B. , Middleton Michael S. 
Published: December 2010

AbstractA theoretical triglyceride model was developed for in vivo human liver fat 1H MRS characterization, using the number of double bonds (CHCH), number of methylene‐interrupted double bonds (CHCHCH2CHCH) and average fatty acid chain length. Five 3 T, single‐voxel, stimulated echo acquisition mode spectra (STEAM) were acquired consecutively at progressively longer TEs in a fat–water emulsion phantom and in 121 human subjects with known or suspected nonalcoholic fatty liver disease. T2‐corrected peak areas were calculated. Phantom data were used to validate the model. Human data were used in the model to determine the complete liver fat spectrum. In the fat–water emulsion phantom, the spectrum predicted by the model (based on known fatty acid chain distribution) agreed closely with spectroscopic measurement. In human subjects, areas of CH2 peaks at 2.1 and 1.3 ppm were linearly correlated (slope, 0.172; r = 0.991), as were the 0.9 ppm CH3 and 1.3 ppm CH2 peaks (slope, 0.125; r = 0.989). The 2.75 ppm CH2 peak represented 0.6% of the total fat signal in high‐liver‐fat subjects. These values predict that 8.6% of the total fat signal overlies the water peak. The triglyceride model can characterize human liver fat spectra. This allows more accurate determination of liver fat fraction from MRI and MRS. Copyright © 2010 John Wiley & Sons, Ltd.
In vivo characterization of tissue thermal properties of the kidney during local hyperthermia induced by MR‐guided high‐intensity focused ultrasound
Authors: Cornelis François , Grenier Nicolas , Moonen Chrit T , Quesson Bruno 
Published: December 2010

AbstractThe purpose of this study was to evaluate quantitatively in vivo the tissue thermal properties during high‐intensity focused ultrasound (HIFU) heating. For this purpose, a total of 52 localized sonications were performed in the kidneys of six pigs with HIFU monitored in real time by volumetric MR thermometry. The kidney perfusion was modified by modulation of the flow in the aorta by insertion of an inflatable angioplasty balloon. The resulting temperature data were analyzed using the bio‐heat transfer model in order to validate the model under in vivo conditions and to estimate quantitatively the absorption (α), thermal diffusivity (D) and perfusion (wb) of renal tissue. An excellent correspondence was observed between the bio‐heat transfer model and the experimental data. The absorption and thermal diffusivity were independent of the flow, with mean values (± standard deviation) of 20.7 ± 5.1 mm3 K J−1 and 0.23 ± 0.11 mm2 s−1, respectively, whereas the perfusion decreased significantly by 84% (p < 0.01) with arterial flow (mean values of wb of 0.06 ± 0.02 and 0.008 ± 0.007 mL−1 mL s−1), as predicted by the model. The quantitative analysis of the volumetric temperature distribution during nondestructive HIFU sonication allows the determination of the thermal parameters, and may therefore improve the quality of the planning of noninvasive therapy with MR‐guided HIFU. Copyright © 2010 John Wiley & Sons, Ltd.
MRI and quantitative autoradiographic studies following bolus injections of unlabeled and 14C‐labeled gadolinium‐diethylenetriaminepentaacetic acid in a rat model of stroke yield similar distribution volumes and blood‐to‐brain influx rate constants
Authors: Nagaraja Tavarekere N. , Ewing James R. , Karki Kishor , Jacobs Paul E. , Divine George W. , Fenstermacher Joseph D. , Patlak Clifford S. , Knight Robert A. 
Published: December 2010

AbstractIn previous studies on a rat model of transient cerebral ischemia, the blood and brain concentrations of gadolinium‐diethylenetriaminepentaacetic acid (Gd‐DTPA) following intravenous bolus injection were repeatedly assessed by dynamic contrast‐enhanced (DCE)‐MRI, and blood‐to‐brain influx rate constants (Ki) were calculated from Patlak plots of the data in areas with blood–brain barrier (BBB) opening. For concurrent validation of these findings, after completing the DCE‐MRI study, radiolabeled sucrose or α‐aminoisobutyric acid was injected intravenously, and the brain disposition and Ki values were calculated by quantitative autoradiography (QAR) assay employing the single‐time equation. To overcome two of the shortcomings of this comparison, the present experiments were carried out with a radiotracer virtually identical to Gd‐DTPA, Gd‐[14C]DTPA, and Ki was calculated from both sets of data by the single‐time equation. The protocol included 3 h of middle cerebral artery occlusion and 2.5 h of reperfusion in male Wistar rats (n = 15) preceding the DCE‐MRI Gd‐DTPA and QAR Gd‐[14C]DTPA measurements. In addition to Ki, the tissue‐to‐blood concentration ratios, or volumes of distribution (VR), were calculated. The regions of BBB opening were similar on the MRI maps and autoradiograms. Within them, VR was nearly identical for Gd‐DTPA and Gd‐[14C]DTPA, and Ki was slightly, but not significantly, higher for Gd‐DTPA than for Gd‐[14C]DTPA. The Ki values were well correlated (r = 0.67; p = 0.001). When the arterial concentration–time curve of Gd‐DTPA was adjusted to match that of Gd‐[14C]DTPA, the two sets of Ki values were equal and statistically comparable with those obtained previously by Patlak plots (the preferred, less model‐dependent, approach) of the same data (p = 0.2–0.5). These findings demonstrate that this DCE‐MRI technique accurately measures the Gd‐DTPA concentration in blood and brain, and that Ki estimates based on such data are good quantitative indicators of BBB injury. Copyright © 2010 John Wiley & Sons, Ltd.
Increasing accuracy and efficiency in FE computations of the Leray‐Deconvolution model
Authors: Bowers Abigail L. , Rebholz Leo G. 
Published: December 2010

AbstractThis article develops, analyzes, and tests a finite element method for approximating solutions to the Leray‐deconvolution regularization of the Navier‐Stokes equations. The scheme combines three ideas to create an accurate and effective algorithm: the use of an incompressible filter, a linearization that decouples the velocity‐pressure system from the filtering and deconvolution operations, and a stabilization that works well with the linearization. A rigorous and complete numerical analysis of the scheme is given, and numerical experiments are presented that show clear advantages of the scheme. © 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 720–736, 2012
Local government discretion and accountability in Burkina Faso
Authors: Mahieu Sylvie , Yilmaz Serdar 
Published: December 2010

AbstractBurkina Faso opted for a progressive approach to decentralization reforms, aiming at building local government capacity first before transferring responsibilities. We employ a diagnostic framework to analyze local government discretion and accountability in Burkina Faso. We find that local governments have a very low degree of discretionary power accompanied with weak accountability towards citizens at all levels. In the political and administrative spheres, the center plays a dominant role in local government affairs leaving little space for discretion. In the fiscal sphere, taxing powers are restricted, while transfers are insufficient and unpredictable, making local financial management extremely difficult. Copyright © 2010 John Wiley & Sons, Ltd.