bluuebunny/crossref_metadata_2025 huggingface dataset:
Observation of a Collapsing Layer Structure in Mg/Al Layered Double Hydroxides with Interlayer Hydrogen Phosphate by High Temperature In Situ X-Ray Diffraction with Synchrotoron Radiation
Authors: Shimamura Akihiro , Perander Linus , Kanezaki Eiji , Jones Mark Ian , Metson James B.
Published: September 2011

The collapsing layer structure of hydrogen phosphate intercalated Mg/Al-layered double hydroxides (LDH-HPO4) was investigated by high temperature in-situ X-ray diffraction with synchrotron radiation (in-situ XRD). The thermal behavior of the layer structure of LDH-HPO4 showed the same behavior in both in-situ and ex-situ XRD up until 109 °C as previously reported. The basal spacing of LDH-HPO4 continuously decreases above this temperature and finally the layer structure of LDH-HPO4 collapses. Another diffraction peak, d110, which gives a lattice constant a0, decreases at 62 °C, keeps constant to 120°C, increases up to 176°C and again keeps constant until the layer collapse. In this study, the different thermal behavior is observed between two reflections by in-situ XRD measurement, which explains the mechanism of the collapse of the layer structure in LDH-HPO4.
Thin Films of Cupric Oxide: Crystallite Size and Conduction Mechanism Analysis
Authors: Ravi Shrividya , Kaiser Alan B. , Bumby Christopher W.
Published: September 2011

Nanocrystalline lms of cupric oxide (CuO) produced by thermal oxidation havebeen characterised using x-ray analysis, SEM image analysis and temperature-dependent con-duction measurements.We describe in detail the x-ray di ractometer calibration, paying partic-ular attention to a function- tting procedure which enables accurate subtraction of instrumentalcontributions to the sample di ractograms. The Scherrer and Williamson-Hall models are usedto calculate crystallite size and sample strain and also give some indication of spatial inhomo-geneity. Image analysis techniques which can discern individual `grains' (the circular Houghtransform and the ImageJ particle analyser) were used to evaluate the grain size distributionfrom SEM images. An average crystallite diameter of 30 nm - determined by the ImageJ par-ticle analyser - closely agrees with the various XRD analysis approaches. Electronic conductionin our samples is found to proceed via thermally activated transport, which we attribute tothe presence of a well-de ned trap state that lies 0.2 eV from the valence band edge. Thevoltage-dependence of the activation energy additionally shows that the activation is a bulke ect and not due to Schottky barriers between the sample and the metal contact.
Charge Carrier Localisation in Disordered Graphene Nanoribbons
Authors: Schubert Gerald , Fehske Holger
Published: September 2011

We study the electronic properties of actual-size graphene nanoribbons subjected tosubstitutional disorder particularly with regard to the experimentally observed metal-insulatortransition. Calculating the local, mean and typical density of states, as well as the time-evolutionof the particle density we comment on a possible disorder-induced localisation of charge carriersat and close to the Dirac point within a percolation transition scenario.
MHC-Independent Genetic Factors Control the Magnitude of CD4+ T Cell Responses to Amyloid-β Peptide in Mice through Regulatory T Cell-Mediated Inhibition
Authors: Toly-Ndour Cécile , Lui Gabrielle , Manuel Nunes Maria , Bruley-Rosset Martine , Aucouturier Pierre , Dorothée Guillaume
Published: September 2011

Accumulation of amyloid-β peptide (Aβ) is considered the triggering factor of pathogenic lesions in Alzheimer’s disease (AD), and vaccines targeting Aβ are promising therapeutic options. However, the occurrence of meningoencephalitides attributed to T cell responses in 6% of Aβ-immunized patients underscores the need for a better understanding of T cell responses to Aβ. We characterized the parameters controlling the magnitude of Aβ-specific CD4+ T cell responses in mice. T cell responsiveness to Aβ1-42 was highly heterogeneous between mouse strains of different H-2 haplotypes, with SJL/J (H-2s) mice displaying a strong response, mainly specific for Aβ10-24, and C57BL/6 (H-2b) mice displaying a weak response to Aβ16-30. Surprisingly, C57BL/6 mice congenic for the H-2s haplotype (B6.H-2S), which display a “permissive” MHC class II allele for presentation of the immunodominant Aβ10-24 epitope, showed a very weak CD4+ T cell response to Aβ, suggesting that MHC-independent genes downmodulate Aβ-specific CD4+ T cell responses in C57BL/6 background. Vaccine-induced CD4+ T cell responses to Aβ were significantly enhanced in both C57BL/6 and B6.H-2S mice upon depletion of regulatory T cells (Tregs), whereas Treg-depleted SJL/J mice displayed unaltered Aβ-specific T cell responses. Finally, Treg depletion in C57BL/6 transgenic APPPS1 mice, a mouse model of AD, results in enhanced vaccine-induced CD4+ T cell responses in AD compared with wild-type animals. We concluded that the magnitude of Aβ-specific CD4+ T cell responses is critically controlled in both physiological and pathological settings by MHC-independent genetic factors that determine the overall potency of Aβ-specific Treg responses.
Constitutive heterochromatin polymorphisms in human chromosomes identified by whole comparative genomic hybridization
Authors: DÃ¡vila-RodrÃ­guez M.I. , CortÃ©s-GutiÃ©rrez Elva I. , Cerda Flores R.M. , Pita M. , FernÃ¡ndez J.L. , LÃ³pez-FernÃ¡ndez C. , GosÃ¡lvez J.
Published: September 2011

Whole comparative genomic hybridization (W-CGH) is a new technique that reveals cryptic differences in highly repetitive DNA sequences, when different genomes are compared using metaphase or interphase chromosomes. W-CGH provides a quick approach to identify differential expansion of these DNA sequences at the single-chromosome level in the whole genome. In this study, we have determined the frequency of constitutive chromatin polymorphisms in the centromeric regions of human chromosomes using a whole-genome in situ cross-hybridization method to compare the whole genome of five different unrelated individuals. Results showed that the pericentromeric constitutive heterochromatin of chromosome 6 exhibited a high incidence of polymorphisms in repetitive DNA families located in pericentromeric regions. The constitutive heterochromatin of chromosomes 5 and 9 was also identified as highly polymorphic. Although further studies are necessary to corroborate and assess the overall incidence of these polymorphisms in human populations, the use of W-CGH could be pertinent and of clinical relevance to assess rapidly, from a chromosomal viewpoint, genome similarities and differences in closely related genomes such as those of relatives, or in more specific situations such as bone marrow transplantation where chimerism is produced in the recipient.
Compliance amongst asthma patients registered for an asthma disease risk-management programme in South Africa
Authors: Opedun Ntombombuso , Ehlers Valerie J. , Roos Janetta H.
Published: September 2011

The study attempted to identify the factors that influence compliance amongst 1039 members and their dependants of a particular medical aid scheme in South Africa who were registered for an asthma disease risk-management (DRM) programme. The sample consisted of 200 systematically selected individuals or their dependants. A quantitative, exploratory, and descriptive study was undertaken. Questionnaires for completion were posted to the individuals or their dependants. The Statistica 7.1 computer program was used to analyse the data.Most asthma patients did not comply with the DRM programme because they lacked knowledge of the programme. Asthma patients’ compliance with the DRM programme can be enhanced by the sustained, positive attitudes of their health providers and case managers; better promotion of the programme; and by involving the patients to a greater extent in the long-term management of their disease.Asthma patients require education about healthy lifestyles that would empower them to successfully manage their condition, which would prevent or at least reduce asthma attacks and/or hospital admissions.
Cyto-morphological features of extramedullary acute megakaryoblastic leukemia on fine needle aspiration and cerebrospinal fluid cytology: A case report
Authors: Chitragar Sanjeev , Agarwal Shipra , Iyer Venkateswaran K. , Mathur Sandeep R. , Karak Asis K. , Chharchhodawala Taher , Sharma Atul , Bakhshi Sameer
Published: September 2011

Extramedullary deposits may be the presenting feature of acute myeloid leukemia. An early and accurate diagnosis on cytology will aid in correct patient management. This is especially true for patients with acute megakaryoblastic leukemia (AML M7), where bone marrow aspiration may yield only a dry tap. While cytomorphological features of myeloid sarcoma of other types are well recognized due to its rarity, there are only two case reports discussing the morphological details of megakaryoblastic differentiation on aspiration cytology. We present the case of a 25-year-old patient with extramedullary involvement of lymph node and cerebrospinal fluid by AML M7, describing in detail, the morphological features on aspiration as well as exfoliative cytology.
Longpath DOAS observations of surface BrO at Summit, Greenland
Authors: Stutz J. , Thomas J. L. , Hurlock S. C. , Schneider M. , von Glasow R. , Piot M. , Gorham K. , Burkhart J. F. , Ziemba L. , Dibb J. E. , Lefer B. L.
Published: September 2011

Abstract. Reactive halogens, and in particular bromine oxide (BrO), have frequently been observed in regions with large halide reservoirs, for example during bromine catalyzed coastal polar ozone depletion events. Much less is known about the presence and impact of reactive halogens in areas without obvious halide reservoirs, such as the polar ice sheets or continental snow. We report the first LP-DOAS measurements of BrO at Summit research station in the center of the Greenland ice sheet at an altitude of 3200 m. BrO mixing ratios in May 2007 and June 2008 were typically between 1–3 pmol mol−1, with maxima of up to 5 pmol mol−1. These measurements unequivocally show that halogen chemistry is occurring in the remote Arctic, far from known bromine reservoirs, such as the ocean. During periods when FLEXPART retroplumes show that airmasses resided on the Greenland ice sheet for 3 or more days, BrO exhibits a clear diurnal variation, with peak mixing ratios of up to 3 pmol mol−1 in the morning and at night. The diurnal cycle of BrO can be explained by a changing boundary layer height combined with photochemical formation of reactive bromine driven by solar radiation at the snow surface. The shallow stable boundary layer in the morning and night leads to an accumulation of BrO at the surface, leading to elevated BrO despite the expected smaller release from the snowpack during these times of low solar radiation. During the day when photolytic formation of reactive bromine is expected to be highest, efficient mixing into a deeper neutral boundary layer leads to lower BrO mixing ratios than during mornings and nights. The extended period of contact with the Greenland snowpack combined with the diurnal profile of BrO, modulated by boundary layer height, suggests that photochemistry in the snow is a significant source of BrO measured at Summit during the 2008 experiment. In addition, a rapid transport event on 4 July 2008, during which marine air from the Greenland east coast was rapidly transported to Summit, led to enhanced mixing ratios of BrO and a number of marine tracers. However, rapid transport of marine air from the Greenland east coast is rare and most likely not the main source of bromide in surface snow at Summit. The observed levels of BrO are predicted to influence NOx chemistry as well as impact HOx partitioning. However, impact of local snow photochemistry on HOx is smaller than previously suggested for Summit.
Observations of the boundary layer, cloud, and aerosol variability in the southeast Pacific near-coastal marine stratocumulus during VOCALS-REx
Authors: Zheng X. , Albrecht B. , Jonsson H. H. , Khelif D. , Feingold G. , Minnis P. , Ayers K. , Chuang P. , Donaher S. , Rossiter D. , Ghate V. , Ruiz-Plancarte J. , Sun-Mack S.
Published: September 2011

Abstract. Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20° S, 72° W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud- Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP) varied between 15 g m−2 and 160 g m−2. The BL had a depth of 1140 ± 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and meso-scale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October–4 November), a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm−3 within the BL, and CCN at 0.2 % supersaturation within the BL ranged between 150 and 550 cm−3. The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm−3. While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft in situ observations near cloud top. The aerosol and cloud LWP relationship reveals that during the typical well-mixed BL days the cloud LWP increased with the CCN concentrations. On the other hand, meteorological factors and the decoupling processes have large influences on the cloud LWP variation as well.
Decreased summer drought affects plant productivity and soil carbon dynamics in a Mediterranean woodland
Authors: Cotrufo M. F. , Alberti G. , Inglima I. , Marjanović H. , LeCain D. , Zaldei A. , Peressotti A. , Miglietta F.
Published: September 2011

Abstract. Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.
Continental atmospheric circulation over Europe during the Little Ice Age inferred from grape harvest dates
Authors: Yiou P. , García de Cortázar-Atauri I. , Chuine I. , Daux V. , Garnier E. , Viovy N. , van Leeuwen C. , Parker A. K. , Boursiquot J.-M.
Published: September 2011

Abstract. Estimates of climate conditions before the 19th century are based on proxy data reconstructions or sparse meteorological measurements. The reconstruction of the atmospheric circulation that prevailed during the European Little Ice Age (~1500–1850) has fostered many efforts. This study illustrates a methodology combining historical proxies and modern data sets to obtain detailed information on the atmospheric circulation that prevailed over the North Atlantic region during the Little Ice Age. We use reconstructions of temperature gradients over France based on grape harvest dates to infer the atmospheric circulation. We find that blocking situations were more likely in summer, inducing a continental atmospheric flow. This study advocates that the reconstructions of the past atmospheric circulation should take this regime into account.
FAMOUS, faster: using parallel computing techniques to accelerate the FAMOUS/HadCM3 climate model with a focus on the radiative transfer algorithm
Authors: Hanappe P. , Beurivé A. , Laguzet F. , Steels L. , Bellouin N. , Boucher O. , Yamazaki Y. H. , Aina T. , Allen M.
Published: September 2011

Abstract. We have optimised the atmospheric radiation algorithm of the FAMOUS climate model on several hardware platforms. The optimisation involved translating the Fortran code to C and restructuring the algorithm around the computation of a single air column. Instead of the existing MPI-based domain decomposition, we used a task queue and a thread pool to schedule the computation of individual columns on the available processors. Finally, four air columns are packed together in a single data structure and computed simultaneously using Single Instruction Multiple Data operations. The modified algorithm runs more than 50 times faster on the CELL's Synergistic Processing Element than on its main PowerPC processing element. On Intel-compatible processors, the new radiation code runs 4 times faster. On the tested graphics processor, using OpenCL, we find a speed-up of more than 2.5 times as compared to the original code on the main CPU. Because the radiation code takes more than 60 % of the total CPU time, FAMOUS executes more than twice as fast. Our version of the algorithm returns bit-wise identical results, which demonstrates the robustness of our approach. We estimate that this project required around two and a half man-years of work.
Spatial horizontal correlation characteristics in the land data assimilation of soil moisture and surface temperature
Authors: Han X. , Li X. , Hendricks Franssen H. J. , Vereecken H. , Montzka C.
Published: September 2011

Abstract. Remote sensing images deliver important information about soil moisture and soil temperature, but often cover only part of an area, for example due to the presence of clouds or vegetation. This paper examines the potential of incorporating the spatial horizontal correlation characteristics of observations of surface soil moisture and surface temperature in data assimilation to get improved estimations of soil moisture and soil temperature at such uncovered grid cells. Observing system simulation experiments were carried out to assimilate the synthetic surface soil moisture and surface temperature observations into the community land model (CLM) for the Babaohe River Basin in northwestern China. The estimations of soil moisture at the uncovered grids (i.e., grid cells without observations) were improved when information from surrounding observations was included considering the spatial correlation. An increasing number of observations led to a better prediction of soil moisture with an upper limit of nine observations. A further increase of the number of observations did not improve much the results in this case. Even the estimation for the covered grid cells was improved when multiple observations were included in the LETKF. The results of surface temperature assimilation show that for the covered grids (i.e., grid cells with observations), more observations will not improve the estimations, and one nearest observation is enough to obtain the best estimation. For the uncovered grids, more observations will be better. The estimations at the uncovered grids could be improved when the surrounding correlated observations were used. In summary, the spatial horizontal correlations of soil moisture and surface temperature were found to be helpful to the surface soil moisture and surface temperature data assimilation through this study, especially for uncovered grid cells.
Simulation of permafrost and seasonal thaw depth in the JULES land surface scheme
Authors: Dankers R. , Burke E. J. , Price J.
Published: September 2011

Abstract. Land surface models (LSMs) need to be able to simulate realistically the dynamics of permafrost and frozen ground. In this paper we evaluate the performance of the LSM JULES (Joint UK Land Environment Simulator), the stand-alone version of the land surface scheme used in Hadley Centre climate models, in simulating the large-scale distribution of surface permafrost. In particular we look at how well the model is able to simulate the seasonal thaw depth or active layer thickness (ALT). We performed a number of experiments driven by observation-based climate datasets. Visually there is a very good agreement between areas with permafrost in JULES and known permafrost distribution in the Northern Hemisphere, and the model captures 97% of the area where the spatial coverage of the permafrost is at least 50%. However, the model overestimates the total extent as it also simulates permafrost where it occurs sporadically or only in isolated patches. Consistent with this we find a cold bias in the simulated soil temperatures, especially in winter. However, when compared with observations on end-of-season thaw depth from around the Arctic, the ALT in JULES is generally too deep. Additional runs at three sites in Alaska demonstrate how uncertainties in the precipitation input affect the simulation of soil temperatures by affecting the thickness of the snowpack and therefore the thermal insulation in winter. In addition, changes in soil moisture content influence the thermodynamics of soil layers close to freezing. We also present results from three experiments in which the standard model setup was modified to improve physical realism of the simulations in permafrost regions. Extending the soil column to a depth of 60 m and adjusting the soil parameters for organic content had relatively little effect on the simulation of permafrost and ALT. A higher vertical resolution improves the simulation of ALT, although a considerable bias still remains. Future model development in JULES should focus on a dynamic coupling of soil organic carbon content and soil thermal and hydraulic properties, as well as allowing for sub-grid variability in soil types.
Longitudinal Effects of Different Types of Practice on the Development of Chess Expertise
Authors: Howard Robert W.
Published: September 2011

A view holds that expertise level depends on practice alone and that certain types of practice are important or unimportant. Supporting evidence largely comes from studies using a correlational retrospective recall paradigm, usually with small samples. Initially, these studies were partially replicated with 533 international chess players. Log number of games played was the strongest predictor of latest performance rating. Then, effects of study hours, having had coaching and the number of games played were examined longitudinally to control for key variables confounded in the retrospective recall paradigm. Groups with a nearly 5–1 median difference in weekly study hours, roughly equated on time in the domain and the number of games played, were observed over 7 years. More study hours had negligible impact. Coaching had some effect over time, and the number of games had a strong effect even when participants were equated on time in the domain. Previous studies show that a factor other than the number of games is important in developing chess expertise. Study is a weak factor at best and could not be that important factor. Chess expertise apparently does not depend on practice (study and the number of games) alone. Copyright © 2011 John Wiley & Sons, Ltd.
Improved Performance of Polymer:Polymer Solar Cells by Doping Electron‐Accepting Polymers with an Organosulfonic Acid
Authors: Nam Sungho , Shin Minjung , Kim Hwajeong , Ha Chang‐Sik , Ree Moonhor , Kim Youngkyoo
Published: September 2011

The performance of polymer:polymer solar cells that are made using blend films of poly(3‐hexylthiophene) (P3HT) and poly(9,9‐dioctylfluorene‐co‐ benzothiadiazole (F8BT) is improved by doping the F8BT polymer with an organosulfonic acid [4‐ethylbezenesulfonic acid (EBSA)]. The EBSA doping of F8BT, to form F8BT‐EBSA, is performed by means of a two‐stage reaction at room temperature and 60°C with various EBSA weight ratios. The X‐ray photoelectron spectroscopy measurement reveals that both sulfur and nitrogen atoms in the F8BT polymer are affected by the EBSA doping. The F8BT‐EBSA films exhibit huge photoluminescence quenching, ionization potential shift toward lower energy, and greatly enhanced electron mobility. The short‐circuit current density of solar cells is improved by ca. twofold (10 wt.% EBSA doping), while the open‐circuit voltage increases by ca. 0.4 V. Consequently, the power conversion efficiency was improved by ca. threefold, even though the optical density of the P3HT:F8BT‐EBSA blend film is reduced by 10 wt.% EBSA doping due to the nanostructure and surface morphology change.
Microtribology of Aqueous Carbon Nanotube Dispersions
Authors: Kristiansen Kai , Zeng Hongbo , Wang Peng , Israelachvili Jacob N.
Published: September 2011

The tribological behavior of carbon nanotubes (CNTs) in aqueous humic acid (HA) solutions was studied using a surface forces apparatus (SFA) and shows promising lubricant additive properties. Adding CNTs to the solution changes the friction forces between two mica surfaces from “adhesion controlled” to “load controlled” friction. The coefficient of friction with either single‐walled (SW) or multi‐walled (MW) CNT dispersions is in the range 0.30–0.55 and is independent of the load and sliding velocity. More importantly, lateral sliding promotes a redistribution or accumulation, rather than squeezing out, of nanotubes between the surfaces. This accumulation reduced the adhesion between the surfaces (which generally causes wear/damage of the surfaces), and no wear or damage was observed during continuous shearing experiments that lasted several hours even under high loads (pressures ∼10 MPa). The frictional properties can be understood in terms of the Cobblestone Model where the friction force is related to the fraction of the adhesion energy dissipated during impacts of the nanoparticles. We also develop a simple generic model based on the van der Waals interactions between particles and surfaces to determine the relation between the dimensions of nanoparticles and their tribological properties when used as additives in oil‐ or water‐based lubricants.
Shape‐Controlled Synthesis of Polyhedral Nanocrystals and Their Facet‐Dependent Properties
Authors: Huang Michael H. , Lin Po‐Heng
Published: September 2011

Growth of inorganic polyhedral nanocrystals with excellent morphology control presents significant synthetic challenges, especially when the development of synthetic schemes to make nanocrystals with systematic shape evolution is desired. Nanocrystals with fine size and shape control facilitate formation of their self‐assembled packing structures and offer opportunities for examination of their facet‐dependent physical and chemical properties. In this Feature Article, recent advances in the synthesis of nanocrystals with systematic shape evolution are highlighted. The reaction conditions used to achieve this morphology change offer insights into the growth mechanisms of nanocrystals. A novel class of polyhedral core–shell heterostructures fabricated using structurally well‐defined nanocrystal cores is also presented. Facet‐dependent photocatalytic activity, molecular adsorption, and catalytic and electrical properties of nanocrystals have been examined and are discussed. Nanomaterials with enhanced properties and functionality may be obtained through continuous efforts in the synthesis of nanocrystals with well‐defined structures and investigation of their plane‐selective properties.
Operando Spectroscopy: the Knowledge Bridge to Assessing Structure–Performance Relationships in Catalyst Nanoparticles
Authors: Bañares Miguel A.
Published: September 2011

Progress in nanomaterials and catalysis stands on three pillars: 1) synthesis of nanomaterials, including the preparation of hierarchically dispersed nanoparticles; 2) theoretical studies of materials that enable experimental results to be understood; and 3) advanced, in situ characterization during operation (operando methodology). This Research News brings a perspective on how these three pillars are blending for research in materials science, with particular emphasis on catalysis.
Low protein fouling polypropylene membrane prepared by photoinduced reversible addition‐fragmentation chain transfer polymerization
Authors: Hu Bing , Wang Liang , Wu Xiu‐Min , Yang Song , Gu Jia‐Shan , Yu Hai‐Yin
Published: September 2011

In this study, 2‐hydroxyethyl methacrylate and N‐isopropyl acrylamide was block grafted onto the polypropylene macroporous membrane surface by photo‐induced reversible addition‐fragmentation chain transfer (RAFT) radical polymerization with benzyl dithiobenzoate as the RAFT agent. The degree of grafting of poly(2‐hydroxyethyl methacrylate) on the membrane surface increased with UV irradiation time and decreased with the chain transfer agent concentration increasing. The poly(2‐hydroxyethyl methacrylate)‐ grafted membranes were used as macro chain transfer agent for the further block graft copolymerization of N‐isopropyl acrylamide in the presence of free radical initiator. The degree of grafting of poly(N‐isopropyl acrylamide) increased with reaction time. Furthermore, the poly(2‐hydroxyethyl methacrylate)‐ grafted membrane with a degree of grafting of 0.48% (wt) showed the highest relative pure water flux and the best antifouling characteristics of protein dispersion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and characterization of novel grafted cellophane‐phosphoric acid‐doped membranes for proton exchange membrane fuel‐cell applications
Authors: Abu‐Saied M. A. , Elzatahry A. A. , El‐Khatib K. M. , Hassan E. A. , El‐Sabbah M. M. , Drioli E. , Mohy Eldin M. S.
Published: September 2011

This work concerns preparation of acid‐base polyelectrolyte membranes for fuel‐cell applications from cellulosic backbones for the first time. Grafted cellophane‐phosphoric acid‐doped membranes for direct oxidation methanol fuel cells (DMFC) were prepared following three steps. The first two steps were conducted to have the basic polymers. The first step was introducing of epoxy groups to its chemical structure through grafting process with poly(glycidylmethacrylate) (PGMA). The second step was converting the introduced epoxy groups to imides groups followed by phosphoric acid (PO3H) doping as the last step. This step significantly contributes to induce ion exchange capacity (IEC) and ionic conductivity (IC). Chemical changes of the cellophane composition and morphology characters were followed using FTIR, TGA, and SEM analysis. Different factors affecting the membranes characters especially IEC, methanol permeability, and thermal stability were investigated and optimized to have the best preparation conditions. Compared to Nafion 117 membrane, cellophane‐modified membranes show a better IEC, less methanol permeability, and better mechanical and thermal stability. IEC in the range of 1–2.3 meq/g compared to 0.9 meq/g per Nafion was obtained, and methanol permeability has been reduced by one‐order magnitude. However, the maximum obtained IC for cellophane‐PGMA‐grafted membrane doped with phosphoric acid was found 2.33 × 10−3 (S cm−1) compared to 3.88 × 10−2 (S cm−1) for Nafion 117. The obtained results are very promising for conducting further investigations taking into consideration the very low price of cellophane compared to Nafion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A critical reflection on the success of rearing and culturing juvenile freshwater mussels with a focus on the endangered freshwater pearl mussel (Margaritifera margaritifera L.)
Authors: Gum Bernhard , Lange Michael , Geist Juergen
Published: September 2011

Freshwater mussels are in decline throughout their range. The lack of natural recruitment in freshwater pearl mussel populations and other freshwater molluscs has led to controversies about the usefulness and applicability of captive breeding techniques for their conservation.

The current state of rearing and culturing programmes for freshwater mussels in Europe and North America is reviewed here with a focus on the endangered freshwater pearl mussel (Margaritifera margaritifera). Different strategies of propagation and the key factors of success are addressed and conservation management decisions are discussed with respect to risk reduction and the intensity of the culturing system.

Based on the rearing techniques applied for multiple species in North America, and for the genus Margaritifera in European countries, sufficient numbers of juveniles can be produced to sustain selected populations. However, captive breeding and stocking should be carefully documented and must not replace the restoration of functional stream habitats.

From a conservation point of view, captive breeding of endangered mussel species can be a last‐minute rescue tool in order to retain the evolutionary potential of priority populations which would not persist long enough to benefit from habitat restoration practices.

Copyright © 2011 John Wiley & Sons, Ltd.
A growth factor delivery system for chondrogenic induction of infrapatellar fat pad‐derived stem cells in fibrin hydrogels
Authors: Ahearne Mark , Buckley Conor T. , Kelly Daniel J.
Published: September 2011

Articular cartilage has a limited capacity for self‐renewal and repair. Tissue engineering of cartilage in vitro has been proposed as a solution to this problem; however, this approach is costly and requires a significant amount of time to grow the graft. An alternative approach is to implant chondroprogenitor cells seeded within a growth factor delivery scaffold directly into the defect site to promote tissue regeneration. The objective of this study was to develop a biocompatible growth factor delivery system capable of promoting chondrogenesis of infrapatellar fat pad (IFP)‐derived stem cells. Transforming growth factor beta‐1 (TGF‐β1) was loaded into gelatin microspheres and incorporated into fibrin hydrogels containing IFP‐derived stem cells. The release of TGF‐β1 was quantified using an enzyme‐linked immunosorbent assay, whereas chondrogenesis was demonstrated histologically and by quantifying sulfated glycosaminoglycan production after 21 days of in vitro culture. TGF‐β1 loaded into gelatin microspheres appeared to be as effective in promoting chondrogenesis of IFP‐derived stem cells as adding TGF‐β1 directly to the medium. The influence of different microsphere fabrication parameters and TGF‐β1 loading concentrations was also investigated but appeared to only have a small effect on subsequent chondrogenesis. The development of such growth factor delivery systems in combination with IFP‐derived stem cells represents a potential new strategy for cartilage defect repair.
A novel method for the extraction and culture of progenitor stem cells from human peripheral blood for use in regenerative medicine
Authors: Punshon Geoffrey , Vara Dina S. , Sales Kevin M. , Seifalian Alexander M.
Published: September 2011

Human peripheral blood (HPB) contains both circulating endothelial cells (CECs) and endothelial progenitor stem cells (EPCs), which may be suitable for use in regenerative medicine. There has been considerable interest in using these cells, but there is no “gold standard” technique for isolating these cells. The aim of this study was to characterize and compare a number of different extraction and culture techniques to develop a system to isolate and culture cells. EPC and CEC were isolated from HPB using either Histopaque‐1077 or Lymphoprep. The two isolation methods were compared for the number of cells isolated, cell metabolism, and RNA expression. Both isolations produced viable cells and were comparable. The tissue culture method employed does have a significant effect on the cell population with regard to medium choice, fetal bovine serum concentration, and surface modification of the culture surface. In conclusion, it can be seen that although this study and previous work can suggest a basis for culture, further work to develop an optimized and agreed “gold standard” culture regime for EPC from HPB is required to maximize the potential of this source of cells for regenerative medicine and to translate its clinical use in the future.
Determination of bismuth in pharmaceutical products using phosphoric acid as molecular probe by resonance light scattering
Authors: Yun Yanru , Cui Fengling , Geng Shaoguang , Jin Jianhua
Published: September 2011

A novel method for the sensitive determination of bismuth(III) in pharmaceutical products using phosphoric acid as a molecular probe by resonance light scattering (RLS) is discussed. In 0.5 mol/L phosphoric acid (H3PO4) medium, bismuth(III) reacted with PO43− to form an ion association compound, which resulted in the significant enhancement of RLS intensity and the appearance of the corresponding RLS spectral characteristics. The maximum scattering peak of the system existed at 364 nm. Under optimal conditions, there was linear relationship between the relative intensity of RLS and concentration of bismuth(III) in the range of 0.06–10.0 µg/mL for the system. A low detection limit for bismuth(III) of 3.22 ng/mL was achieved. The relative standard deviations (RSD) for the determination of 0.40 and 0.80 µg/mL bismuth(III) were 2.1% and 1.1%, respectively, for five determinations. Based on this fact, a simple, rapid, and sensitive method was developed for the determination of bismuth(III) at nanogram level by RLS technique with a common spectrofluorimeter. This analytical system was successfully applied to determine the trace amounts of bismuth(III) in pharmaceutical products, which was in good agreement with the results obtained by atomic absorption spectrometry (AAS). Copyright © 2011 John Wiley & Sons, Ltd.
Economic comparison of diagnostic antibody production in perfusion stirred tank and in hollow fiber bioreactor processes
Authors: Vermasvuori Raisa , Hurme Markku
Published: September 2011

The total operating costs of small‐scale monoclonal antibody production were calculated for two different upstream options and general downstream procedure based on protein A chromatography. The upstream options were a spin‐filter equipped stirred‐tank bioreactor (STR) and a hollow fiber bioreactor (HFB). Both the bioreactors were operated in perfusion mode. The total operating costs of the processes were 6,900 €/g for STR option and 6,400 €/g for the HFB option. In the both systems, the costs were dominated by expenses derived from the downstream section (almost 80%) that was almost identical in the both systems. In the upstream section, the investment depreciation was the largest cost item. The lower total costs of the HFB option were a result of lower investment costs and more concentrated product that led into savings also in downstream section. This study brings out the HFB as on viable alternative for stirred‐tank bioreactor, especially in small‐scale diagnostic monoclonal antibody production. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Effect of Sublimation Treatment on the Catalytic Performance of MFI Catalysts in Pyridine and 3‐Picoline Synthesis
Authors: Jin F. , Wu G. , Li Y.
Published: September 2011

Mordenite framework inverted (MFI)‐structure catalysts with framework trivalent metal cations and extra‐framework metal cations were prepared by the sublimation method to synthesize pyridine and picolines. The results show that the sublimation treatment of volatile metal halides, i.e., GaCl3 and FeCl3, consumes the silanol groups of the parent sample. Most of the Ga cations are incorporated into the zeolite framework, which produces hydroxyl groups and dramatically enhances the proportion of Brönsted acid sites. At the same time, a large number of Fe cations exist in the extra‐framework, causing an increase in the proportion of Lewis acid sites. The increased acid amount and strength effectively improve the activity and stability of the catalyst. Moreover, the generated stronger acid sites increase the selectivity of pyridine. The Ga cations of the modified zeolite can promote the dehydrogenation step for pyridine synthesis, which markedly increases the pyridine selectivity.
Gas Hydrate Formation by Methane‐Helium Mixtures
Authors: Ildyakov A. V. , Manakov A. Y. , Zavjalov A. P. , Bardakhanov S. P.
Published: September 2011

Equilibrium conditions for gas hydrates formed by methane‐helium mixtures with helium concentrations of 31.9, 63.9, and 74.6 mol.‐% have been studied at pressures up to 160 bar. The data obtained indicate that in the studied range of helium concentrations and pressures helium hardly contributes to the stability of the gas hydrate formed. The shift of equilibrium conditions to lower temperatures and higher pressures is caused by dilution of methane in the gas phase and, consequently, the decrease in the chemical potential of methane in the gas phase.
Application of a New Gibbs Energy Equation to Model a Distillation Tower for Production of Pure Ethanol
Authors: Hashemi N. , Pazuki G. , Vossoughi M. , Hemmati S. , Saboohi Y.
Published: September 2011

A steady‐state equilibrium‐stage model based on MESH equations was proposed to simulate saline extractive distillation columns. The interaction parameters between each component of water‐CaCl2 and ethanol‐water were obtained from mean ionic activity coefficients and vapor‐liquid equilibrium (VLE) experimental data. Additionally, the interaction coefficients for the ethanol‐CaCl2 pair were fitted to experimental VLE data which were reported by Nishi for the ethanol‐water‐CaCl2 system. It should be noted that adjustable parameters between each pair were considered to be temperature dependent. The results confirmed that the proposed model could accurately predict the experimental vapor‐liquid equilibrium data for ethanol‐CaCl2‐water systems. Finally, the validated model was coded using MATLAB software and was solved using the Wang‐Henke method, including the VLE and enthalpy models.
Model‐Based Energy Efficiency Optimization of a Low‐Temperature Adsorption Dryer
Authors: Atuonwu J. C. , van Straten G. , van Deventer H. C. , van Boxtel A. J. B.
Published: September 2011

Low‐temperature drying is important for heat‐sensitive products, but at these temperatures conventional convective dryers have low energy efficiencies. To overcome this challenge, an energy efficiency optimization procedure is applied to a zeolite adsorption dryer subject to product quality. The procedure finds a trade‐off between the improved drying capacity due to dehumidification and energy expenditure due to regeneration while incorporating product drying properties. By optimizing the regeneration air inlet temperature, drying air, adsorbent, and regeneration air flow rates as well as sensible and latent heat recovery from the regenerator exhausts, the energy efficiency is improved by up to 45 % compared to the state‐of‐the‐art. The high mass transfer effect of high temperatures is utilized in the regenerator to boost dehumidification while isolating the heat‐sensitive dried product from the quality‐degrading effect.
Orthogonal projection to latent structures solution properties for chemometrics and systems biology data
Authors: Biagioni David J. , Astling David P. , Graf Peter , Davis Mark F.
Published: September 2011

Partial least squares (PLS) is a widely used algorithm in the field of chemometrics. In calibration studies, a PLS variant called orthogonal projection to latent structures (O‐PLS) has been shown to successfully reduce the number of model components while maintaining good prediction accuracy, although no theoretical analysis exists demonstrating its applicability in this context. Using a discrete formulation of the linear mixture model known as Beer's law, we explicitly analyze O‐PLS solution properties for calibration data. We find that, in the absence of noise and for large n, O‐PLS solutions are simpler but just as accurate as PLS solutions for systems in which analyte and background concentrations are uncorrelated. However, the same is not true for the most general chemometric data in which correlations between the analyte and background concentrations are nonzero and pure profiles overlap. On the contrary, forcing the removal of orthogonal components may actually degrade interpretability of the model. This situation can also arise when the data are noisy and n is small, because O‐PLS may identify and model the noise as orthogonal when it is statistically uncorrelated with the analytes. For the types of data arising from systems biology studies, in which the number of response variables may be much greater than the number of observations, we show that O‐PLS is unlikely to discover orthogonal variation whether or not it exists. In this case, O‐PLS and PLS solutions are the same. Copyright © 2011 John Wiley & Sons, Ltd.
ChemInform Abstract: Structural, Electronic and Optical Properties of Spinel Oxides ZnAl2O4, ZnGa2O4 and ZnIn2O4
Authors: Zerarga F. , Bouhemadou A. , Khenata R. , Bin‐Omran S.
Published: September 2011

theoretical study
ChemInform Abstract: Synthesis of in situ Network‐Like Vapor‐Grown Carbon Fiber Improved LiFePO4 Cathode Materials by Microwave Pyrolysis Chemical Vapor Deposition.
Authors: Deng F. , Zeng X. R. , Zou J. Z. , Huang J. F. , Xiong X. B. , Li X. H.
Published: September 2011

The title cathode materials are prepared from mixtures (ball milling for 6 h) of FeC2O4, NH4H2PO4, LiOH, carbon black, and EtOH by microwave pyrolysis chemical vapor deposition (Ar, 800 W microwave output power).
ChemInform Abstract: Electrochemical Lithium Storage Performance of Ternary Zn—Co—Ni Alloy Thin Film as Negative Electrodes by Electrodeposition Method.
Authors: Gnanamuthu R. M. , Lee Chang Woo
Published: September 2011

The title alloy materials, mainly composed of a cubic γ‐Co5Zn21 phase, are synthesized on a copper foil substrate by electroplating using an electrolyte that contains ZnSO4, CoCl2, NiCl2, H3BO3, NaOAc, and NaCl.
ChemInform Abstract: Titania—Lanthanum Phosphate Photoactive and Hydrophobic New Generation Catalyst.
Authors: Jyothi Chembolli K. , Jaimy Kanakkanmavudi B. , Ghosh Swapankumar , Sankar Sasidhara , Smitha V. S. , Warrier K. G. K.
Published: September 2011

TiO2—LaPO4 nanocomposites are prepared by addition of LaPO4 to a TiO2 sol under constant stirring for 3 h, followed by annealing (400—900 °C, 3 h).
ChemInform Abstract: A New Precipitation Based Method for Preparation of Metasilicate Phosphors.
Authors: Talwar G. J. , Joshi C. P. , Moharil S. V. , Dhopte S. M. , Muthal P. L. , Kondawar V. K.
Published: September 2011

Alkaline earth metasilicates MSiO3 (M: Ca, Sr, Ba, Mg) are precipitated from aqueous solutions of metal nitrates by slow addition of Na2SiO3 solution followed by annealing of the formed precipitate (air, 700 °C, 1 h).