bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of the ambient organic aerosol volatility distribution: application during the Finokalia Aerosol Measurement Experiment (FAME-2008)
Authors: Lee B. H. , Kostenidou E. , Hildebrandt L. , Riipinen I. , Engelhart G. J. , Mohr C. , DeCarlo P. F. , Mihalopoulos N. , Prevot A. S. H. , Baltensperger U. , Pandis S. N.
Published: July 2010

Abstract. A variable residence time thermodenuder (TD) was combined with an Aerodyne Aerosol Mass Spectrometer (AMS) and a Scanning Mobility Particle Sizer (SMPS) to measure the volatility distribution of aged organic aerosol in the Eastern Mediterranean during the Finokalia Aerosol Measurement Experiment in May of 2008 (FAME-2008). A new method for the quantification of the organic aerosol volatility distribution was developed combining measurements of all three instruments together with an aerosol dynamics model. Challenges in the interpretation of ambient thermodenuder-AMS measurements include the potential resistances to mass transfer during particle evaporation, the effects of particle size on the evaporated mass fraction, the changes in the AMS collection efficiency and particle density as the particles evaporate partially in the TD, and finally potential losses inside the TD. Our proposed measurement and data analysis method accounts for all of these problems combining the AMS and SMPS measurements. The AMS collection efficiency of the aerosol that passed through the TD was found to be approximately 10% lower than the collection efficiency of the aerosol that passed through the bypass. The organic aerosol measured at Finokalia is approximately 2 orders of magnitude less volatile than fresh laboratory-generated biogenic secondary organic aerosol. This low volatility is consistent with its highly oxygenated AMS mass spectrum. The results are found to be highly sensitive to the mass accommodation coefficient of the evaporating species.
Size-resolved particulate water-soluble organic compounds in the urban, mountain and marine atmosphere
Authors: Wang G. , Kawamura K. , Xie M. , Hu S. , Zhou B. , Li J. , Cao J. , An Z.
Published: July 2010

Abstract. Primary (i.e., sugars and sugar alcohols) and secondary water-soluble organic compounds (WSOCs) (i.e., dicarboxylic acids and aromatic acids) were characterised on a molecular level in size-segregated aerosols from the urban and mountain atmosphere of China and from the marine atmosphere in the outflow region of East Asia. Levoglucosan is the most abundant WSOCs in the urban and mountain atmosphere, whose accumulated concentrations in all stages are 1–3 orders of magnitude higher than those of marine aerosols. In contrast, malic, succinic and phthalic acids are dominant in the marine aerosols, which are 3–6 times more abundant than levoglucosan. This suggests that a continuous formation of secondary organic aerosols is occurring in the marine atmosphere during the long-range transport of air mass from inland China to the North Pacific. Sugars and sugar-alcohols, except for levoglucosan, gave a bimodal size distribution in the urban and mountain areas, peaking at 0.7–1.1 μm and >3.3 μm, and a unimodal distribution in the marine region, peaking at >3.3 μm. In contrast, levoglucosan and all the secondary WSOCs, except for benzoic and azelaic acids, showed a unimodal size distribution with a peak at 0.7–1.1 μm. Geometric mean diameters (GMDs) of the WSOCs in fine particles (<2.1 μm) at the urban site are larger in winter than in spring, due to an enhanced coagulation effect under the development of an inversion layer. However, GMDs of levoglucosan and most of the secondary WSOCs in the coarse mode are larger in the mountain and marine air and smaller in the urban air. This is most likely caused by an enhanced hygroscopic growth due to the high humidity of the mountain and marine atmosphere.
Attribution of stratospheric ozone trends to chemistry and transport: a modelling study
Authors: Kiesewetter G. , Sinnhuber B.-M. , Weber M. , Burrows J. P.
Published: July 2010

Abstract. The decrease of the concentration of ozone depleting substances (ODS) in the stratosphere over the past decade raises the question to what extent observed changes in stratospheric ozone over this period are consistent with known changes in chemical composition and possible changes in atmospheric transport. Here we present a series of ozone sensitivity calculations with a stratospheric chemistry transport model (CTM) driven with meteorological reanalyses from the European Centre for Medium Range Weather Forecast, covering the period 1978–2009. In order to account for the reversal in ODS trends, ozone trends are analysed in two periods, 1979–1999 and 2000–2009. Effects of ODS changes on the ozone chemistry are either accounted for or left out, allowing for a distinct attribution of ozone trends to the different factors of variability, namely ODS acting via gas phase chemistry, ODS acting via polar heterogeneous chemistry, and changes in transport and temperature. Modeled column ozone trends are in excellent agreement with observed trends from the Total Ozone Mapping Spectrometer (TOMS) and Solar Backscatter UV (SBUV/2) as well as the Global Ozone Monitoring Experiment (GOME/GOME2) and Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) instruments. For the 1979–1999 period we find that changes in ODS are the dominant source of the ozone trend, while changes in transport also contribute signifcantly to the overall trend. In contrast, for the period 2000–2009 the effect of ODS changes on total ozone is small. Observed ozone changes can be reproduced well with the CTM driven with meteorological reanalyses, indicating that the observed evolution of ozone over the past decade is consistent with our current understanding of chemistry and transport.
Dynamics of the Antarctic and Arctic mesosphere and lower thermosphere – Part 1: Mean winds
Authors: Sandford D. J. , Beldon C. L. , Hibbins R. E. , Mitchell N. J.
Published: July 2010

Abstract. Zonal and meridional winds have been measured in the upper mesosphere and lower thermosphere at polar latitudes using two ground-based meteor radars. One radar is located at Rothera (68° S, 68° W) in the Antarctic and has been operational since February 2005. The second radar is located at Esrange (68° N, 21° E) in the Arctic and has been operational since October 1999. Both radars have produced relatively continuous measurements. Here we consider measurements made up to the end of 2009. Both radars are of similar design and at conjugate geographical latitudes, making the results directly comparable and thus allowing investigation of the differences in the mean winds of the Antarctic and Arctic regions. The data from each radar have been used to construct climatologies of monthly-mean zonal and meridional winds at heights between 80 and 100 km. Both Antarctic and Arctic data sets reveal seasonally varying zonal and meridional winds in which the broad pattern repeats from year to year. In particular, the zonal winds display a strong shear in summer associated with the upper part of the westward summertime zonal jet. The winds generally reverse to eastward flow at heights of ~90 km. The zonal winds are eastward throughout the rest of the year. The meridional winds are generally equatorward throughout the year over both sites, although brief episodes of poleward flow are often evident near the equinoxes. The strongest equatorward flows occur at heights of ~90 km during summer. There are significant differences between the mean winds observed in the Antarctic and Arctic. In particular, the westward winds in summer are stronger and occur earlier in the season in the Antarctic compared with the Arctic. The eastward winds evident above the summertime zonal wind reversal are significantly stronger in the Arctic. The summertime equatorward flow in the Antarctic is slightly weaker, but occurs over a greater depth than is the case in the Arctic. Comparisons of these observations with those of the URAP and HWM-07 empirical models reveal a number of significant differences. In particular, the zonal winds observed in the Antarctic during wintertime are significantly weaker than those of URAP. However, the URAP zonal winds are a good match to the observations of the Arctic. Significant differences are evident between the observations and HWM-07. In particular, the strong wintertime zonal winds of the Arctic in HWM-07 are not evident in the observations and the summertime zonal winds in HWM-07 are systematically stronger than observed. The agreement with meridional winds is generally poor. There is a significant amount of inter-annual variability in the observed zonal and meridional winds. Particularly high variability is observed in the Arctic zonal winds in spring and is probably associated the stratospheric warmings.
The emission factor of volatile isoprenoids: stress, acclimation, and developmental responses
Authors: Niinemets Ü. , Arneth A. , Kuhn U. , Monson R. K. , Peñuelas J. , Staudt M.
Published: July 2010

Abstract. The rate of constitutive isoprenoid emissions from plants is driven by plant emission capacity under specified environmental conditions (ES, the emission factor) and by responsiveness of the emissions to instantaneous variations in environment. In models of isoprenoid emission, ES has been often considered as intrinsic species-specific constant invariable in time and space. Here we analyze the variations in species-specific values of ES under field conditions focusing on abiotic stresses, past environmental conditions and developmental processes. The reviewed studies highlight strong stress-driven, adaptive (previous temperature and light environment and growth CO2 concentration) and developmental (leaf age) variations in ES values operating at medium to long time scales. These biological factors can alter species-specific ES values by more than an order of magnitude. While the majority of models based on early concepts still ignore these important sources of variation, recent models are including some of the medium- to long-term controls. However, conceptually different strategies are being used for incorporation of these longer-term controls with important practical implications for parameterization and application of these models. This analysis emphasizes the need to include more biological realism in the isoprenoid emission models and also highlights the gaps in knowledge that require further experimental work to reduce the model uncertainties associated with biological sources of variation.
Dating of streamwater using tritium in a post-bomb world: continuous variation of mean transit time with streamflow
Authors: Morgenstern U. , Stewart M. K. , Stenger R.
Published: July 2010

Abstract. Tritium measurements of streamwater draining the Toenepi catchment, a small dairy farming area in Waikato, New Zealand, have shown that the mean transit time of the water varies with the flow of the stream. Mean transit times through the catchment are 2–5 years during high baseflow conditions (in winter), becoming older as streamflow decreases (in summer), and then quite dramatically older during drought conditions, with ages of more than 100 years. Older water seems to be gained in the lower reaches of the stream, compared to younger water in the headwater catchment. The groundwater store supplying baseflow was estimated from the mean transit time and average baseflow to be 15.4×106 m3 of water, about 1 m water equivalent over the catchment and 2.3 times total annual streamflow. Nitrate from recent intensified land use is relatively high at normal streamflow, but is low at times of low flow with old water. This reflects both lower nitrate loading in the catchment several decades ago, and active denitrification processes in older groundwater. Silica, leached from the aquifer material and accumulating in the water in proportion to contact time, is high at times of low streamflow. There was a good correlation between silica and streamwater age, which potentially allows silica concentrations to be used as a proxy for age when calibrated by tritium measurements. This study shows that tritium dating of stream water is possible with single tritium measurements now that bomb-test tritium has effectively disappeared from hydrological systems in New Zealand, without the need for time-series data.
The intensification of rapid reactions for multiphase systems in a microchannel reactor by packing microparticles
Authors: Su Yuanhai , Zhao Yuchao , Jiao Fengjun , Chen Guangwen , Yuan Quan
Published: July 2010

In this study, the nitration of o‐nitrotoluene (NT) with mixed acid as a model fast liquid–liquid multiphase reaction was conducted in the packed and nonpacked microchannel reactors. Better reaction performance could be obtained in the packed microchannel reactor compared with the nonpacked microchannel reactor because of its excellent mass transfer performance. The conversion of NT reached 94% in the packed microchannel reactor even when the reaction time was less than 3 s. A parameter, which represented the coupling of mass transfer and residence time in microdevices, was proposed for explaining and anticipating nitration process in microchannel reactors. In addition, the effects of some operating parameters on reaction performance, such as the composition of mixed acid and reaction temperature, were also investigated experimentally. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Condensation mechanism and influencing factor of stability of complicated silicic acid system
Authors: Li Liaosha , Lu Tingting
Published: July 2010

One complicated silicic acid system, containing Al3+, Mg2+, Fe2+, and Fe3+, is prepared through acidolysis of blast furnace slag. By investigating its gel time concerned with pH value, compared with that of ordinary silicic acid system, it is shown condensation reaction existing and efficiently controlling gelling characteristics of complicated silicic acid system by regulating pH values. The results are validated by FT‐IR spectra analysis. With nonionic surfactant employed, the gel time is increased from 11 to 312 h, more suitable to control gel time than anionic surfactant. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Experimental profiles of lateral mixing of feed particles in a three‐dimensional fluidized bed
Authors: Liu Daoyin , Chen Xiaoping
Published: July 2010

Solids mixing data of high quality is one of the most crucial steps for quantitative studies, but it is a difficult task to obtain in a fluidized bed especially with a 3D configuration. Therefore a novel sampling technique is developed with bed collapse method, for measuring lateral mixing of feed particles in a 3D fluidized bed. The sampling tool is designed using a “bottom‐to‐top sampling” idea. Its development, configuration and measurement repetition are discussed in detail. The effects of mixing time, fluidizing gas velocity, and particle size of bed material on the tracer distribution are investigated. A quantitative comparison of lateral dispersion coefficient shows that our results agree fairly well with measurements and predictions of correlations for lab‐scale fluidized systems in previous studies. The presented 2D profiles of the lateral mixing can be used to validate fundamental solids mixing models or verifying convenient measurement techniques. © 2010 American Institute of Chemical Engineers AIChE J, 2011
Specific gravity and creatinine as corrections for variation in urine concentration in humans, gorillas, and woolly monkeys
Authors: White Brent C. , Jamison Keri M. , Grieb Cassie , Lally Drew , Luckett Cloe , Kramer Katie S. , Phillips Justin
Published: July 2010

Hormones excreted in the urine are widely used to assess the physiological and psychological condition of unrestrained animals. In order to control for variation in the water concentration of urine samples, the hormone concentration is often indexed to the concentration of creatinine. Because there are several problems with using creatinine, we have investigated the efficacy of specific gravity as an alternative basis for adjusting the hormone concentration in humans, gorillas, and woolly monkeys. In an experimental manipulation of human urine hydration, ten volunteers drank a water load proportional to body weight, and provided complete urine collection and saliva samples for four consecutive 20 min intervals. From the urine, we measured cortisol (radioimmunoassay), creatinine (colorimetric assay), and specific gravity (refractometer). Only cortisol was assayed from saliva. During 80 min following water ingestion, cortisol, creatinine, and specific gravity declined as urine became diluted; however, total cortisol excretion remained constant. Only cortisol concentration indexed to specific gravity accurately reflected the consistent cortisol excretion. Specific gravity and creatinine‐corrected cortisol values were highly correlated but were significantly different. Salivary cortisol provided evidence for the relative stability of serum cortisol. To determine the utility of these corrections in other primates, we compared specific gravity‐ and creatinine‐corrected cortisol in urine samples from captive gorillas (N=16) and woolly monkeys (N=8). As with the human study, the two corrections were strongly correlated in each species, but the means were different. Specific gravity correction was superior in revealing the circadian variation in cortisol. Am. J. Primatol. 72:1082–1091, 2010. © 2010 Wiley‐Liss, Inc.
Anwendung von Poly(ethylenglycol) beim Wirkstoff‐Transport: Vorteile, Nachteile und Alternativen
Authors: Knop Katrin , Hoogenboom Richard , Fischer Dagmar , Schubert Ulrich S.
Published: July 2010

Im stetig wachsenden Feld der Polymer‐basierten Wirkstoff‐Transport‐Systeme gilt Poly(ethylenglycol) (PEG) als der Goldstandard für Stealth‐Polymere. Welche Eigenschaften PEG aufweist, die diese herausragende Stellung rechtfertigen, soll in diesem Aufsatz diskutiert werden. Die ersten PEGylierten Produkte erschienen bereits vor 20 Jahren auf dem Markt. Seither konnten viele Erkenntnisse in klinischen Untersuchungen gewonnen werden, allerdings wurden dabei nicht nur Vorteile festgestellt, sondern auch mögliche Nebenwirkungen und Komplikationen bei der Anwendung aufgedeckt. Diese möglichen Nachteile, die eine tiefergehende Untersuchung erfordern, können in folgende Kategorien unterteilt werden: Hypersensitivität, Veränderungen der Pharmakokinetik, toxische Nebenprodukte sowie ein Abbauparadoxon, das aus der Etherstruktur resultiert: Einerseits kann das Polymer relativ einfach unter mechanischer Belastung abgebaut werden, andererseits wird jedoch ein biologischer Abbau verhindert, was bei In‐vivo‐Anwendungen zur Anreicherung im Körper führen kann. Der Aufsatz diskutiert diese möglichen Nachteile und stellt alternative Polymere vor.
Functionalization of multi‐walled carbon nanotubes with poly(ε‐caprolactone) using click chemistry
Authors: Rana Sravendra , Yoo Hye Jin , Cho Jae Whan , Chun Byoung Chul , Park Jong Shin
Published: July 2010

Multi‐walled carbon nanotubes (MWNTs) were covalently functionalized with poly(ε‐caprolactone) (PCL) using click chemistry. First, chlorine moiety‐containing PCL was synthesized by the copolymerization of α‐chloro‐ε‐caprolactone with ε‐caprolactone monomer using ring opening polymerization, and further converted to azide moiety‐containing PCL. The alkyne‐functionalized MWNTs were prepared with the treatment of p‐amino propargyl ether using a solvent free diazotization procedure. The covalent functionalization of alkyne‐derived MWNTs with azide moiety‐containing PCL was accomplished using Cu(I)‐catalyzed [3+2] Huisgen dipolar cycloaddition click chemistry. The PCL‐functionalization of MWNTs was confirmed by the measurements of Fourier transform infra‐red, NMR, Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and characterization of fluorinated polyacrylate graft copolymers capable as water and oil repellent finishing agents
Authors: Tang Weiyi , Huang Yangen , Qing Feng‐Ling
Published: July 2010

A facile method for preparation of fluorinated polyacrylate was developed. Novel multifunctional graft copolymer (GPF‐1, 2, 3) containing short fluoroalkyl side chains and reactive groups were successfully prepared by grafting fluoroalcohols to polyacrylate. The obtained products were characterized by 1H NMR, 19F NMR, FTIR, GPC, TGA, and XPS analyses. GPF‐1, 2, 3 exhibited very low surface free energy (17.77–25.81 mJ/m2). Cotton fabric treated by GPF‐1 had the highest water and oil repellency rating which was 100 and 6, respectively (AATCC test methods). The water and oil repellency rating was kept as 90 and 5, respectively, after 10 soaping cycles or 2 h uninterrupted soaping which indicated a very good washing durability. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Development of the Tarsometatarsal Skeleton by the Lateral Fusion of Three Cylindrical Periosteal Bones in the Chick Embryo (Gallus gallus)
Authors: Namba Yuichi , Yamazaki Yosuke , Yuguchi Maki , Kameoka Shigeo , Usami Shinji , Honda Kazuya , Isokawa Keitaro
Published: July 2010

An avian tarsometatarsal (TMT) skeleton spanning from the base of toes to the intertarsal joint is a compound bone developed by elongation and lateral fusion of three cylindrical periosteal bones. Ontogenetic development of the TMT skeleton is likely to recapitulate the changes occurred during evolution but so far has received less attention. In this study, its development has been examined morphologically and histologically in the chick,Gallus gallus. Three metatarsal cartilage rods radiating distally earlier in development became aligned parallel to each other by embryonic day 8 (ED8). Calcification initiated at ED8 in the midshaft of cartilage propagated cylindrically along its surface. Coordinated radial growth by fabricating bony struts and trabeculae resulted in the formation of three independent bone cylinders, which further became closely apposed with each other by ED13 when the periosteum began to fuse in a back‐to‐back orientation. Bone microstructure, especially orientation of intertrabecular channels in which blood vasculature resides, appeared related to the observed rapid longitudinal growth. Differential radial growth was considered to delineate eventual surface configurations of a compound TMT bone, but its morphogenesis preceded the fusion of bone cylinders. Bony trabeculae connecting adjacent cylinders emerged first at ED17 in the dorsal and ventral quarters of intervening tissue at the mid‐diaphyseal level. Posthatch TMT skeleton had a seemingly uniform mid‐diaphysis, although the septa persisted between original marrow cavities. These findings provide morphological and histological bases for further cellular and molecular studies on this developmental process. Anat Rec 293:1527–1535, 2010. © 2010 Wiley‐Liss, Inc.
Variations in the Thickness and Composition of the Skin of the Giraffe
Authors: Sathar Farzana , Ludo Badlangana N. , Manger Paul R.
Published: July 2010

This study examined the skin of two 1‐ to 2‐year‐old male giraffes and one adult male, determining skin thickness and histological structure with reference to it functioning as a component of the features required for the maintenance of blood pressure, dermal armor, or thermoregulation. It has been argued that a tight skin surrounding the extremities of the giraffe aids in the movement of fluid against gravity, hence preventing pooling of blood and tissue fluid (edema), but the skin has also been implicated in the thermoregulatory capacities and defensive anatomy of many mammalian species. In one of the younger giraffes, one‐half of the skin was analyzed from which close to 170 sites were measured. In the other young and adult giraffes, spot tests to confirm the pattern observed in the fully analyzed individual were undertaken. It was discovered that the skin varied in thickness across the entire body and within regions of the body. Histological evaluation revealed that the skin was mostly collagenous, although interesting patterns of elastic fiber densities were also apparent. The skin in the neck and legs exhibited a morphology that may assist in cardiovascular regulation of blood flow to and from the head and legs, and the skin of the trunk and anterior neck has the possibility of functioning in a protective role. The analyses performed could not add any new data regarding the thermoregulatory role already described for giraffe skin. Anat Rec 293:1615–1627, 2010. © 2010 Wiley‐Liss, Inc.
Stalled replication forks: Making ends meet for recognition and stabilization
Authors: Masai Hisao , Tanaka Taku , Kohda Daisuke
Published: July 2010

In bacteria, PriA protein, a conserved DEXH‐type DNA helicase, plays a central role in replication restart at stalled replication forks. Its unique DNA‐binding property allows it to recognize and stabilize stalled forks and the structures derived from them. Cells must cope with fork stalls caused by various replication stresses to complete replication of the entire genome. Failure of the stalled fork stabilization process and eventual restart could lead to various forms of genomic instability. The low viability of priA null cells indicates a frequent occurrence of fork stall during normal growth that needs to be properly processed. PriA specifically recognizes the 3′‐terminus of the nascent leading strand or the invading strand in a displacement (D)‐loop by the three‐prime terminus binding pocket (TT‐pocket) present in its unique DNA binding domain. Elucidation of the structural basis for recognition of arrested forks by PriA should provide useful insight into how stalled forks are recognized in eukaryotes.
Transcriptional and translational control of C/EBPs: The case for “deep” genetics to understand physiological function
Authors: Nerlov Claus
Published: July 2010

The complexity of organisms is not simply determined by the number of their genes, but to a large extent by how gene expression is controlled. In addition to transcriptional regulation, this involves several layers of post‐transcriptional control, such as translational repression, microRNA‐mediated mRNA degradation and translational inhibition, alternative splicing, and the regulated generation of functionally distinct gene products from a single mRNA through alternative use of translation initiation sites. Much progress has been made in describing the molecular basis for these gene regulatory mechanisms. However, it is now a major challenge to translate this knowledge into deeper understanding of the physiological processes, both normal and pathological, that they govern. Using the C/EBP family of transcription factors as an example, the present review describes recent genetic experiments addressing this general problem and discusses how the physiological importance of newly discovered regulatory mechanisms might be determined.
What an epigenome remembers
Authors: Lange Ulrike C. , Schneider Robert
Published: July 2010

During mammalian development, maintenance of cell fate through mitotic divisions require faithful replication not only of the DNA but also of a particular epigenetic state. Germline cells have the capacity of erasing this epigenetic memory at crucial times during development, thereby resetting their epigenome. Certain marks, however, appear to escape this reprogramming, which allows their transmission to the offspring and potentially guarantees transgenerational epigenetic inheritance. Here we discuss the molecular requirements for faithful transmission of epigenetic information and our current knowledge about the transmission of epigenetic information through generations.
Aromatic Ring Strain in Arylselenenyl Bromides: Role in Facile Synthesis of Selenenate Esters via Intramolecular Cyclization
Authors: Selvakumar K. , Singh Harkesh B. , Butcher Ray J.
Published: July 2010

The synthesis and reactivity of 2,6‐disubstituted arylselenium compounds derived from 2‐bromo‐5‐tert‐butylisophthalic acid (43) are described. The syntheses of bis(5‐tert‐butylisophthalic acid dimethyl ester)diselenide (46) and bis(5‐tert‐butylisophthalic acid diisopropyl ester)diselenide (47) have been achieved by the reaction of the corresponding ester precursors with disodium diselenide. Reduction of diselenide 46 with lithium aluminum hydride affords 2,2′‐bis(5‐tert‐butylbenzene‐1,3‐dimethanol)diselenide (53). Diselenides 46 and 47 exhibit intramolecular Se⋅⋅⋅O interaction. Compound 53 does not show any intramolecular Se⋅⋅⋅O interaction. The anomalous Se⋅⋅⋅O nonbonded coordination observed in the single‐crystal X‐ray structures of compounds 46, 47 and 53 is compared and contrasted. The corresponding selenenyl bromides 54 and 55, derived from the reaction of diselenides 46 and 47 with bromine, are quite stable in the solid state. However, they undergo hydrolysis and subsequent intramolecular cyclization upon heating or after having been kept in solution over a period of time to give the corresponding selenenate esters 56 and 57. The X‐ray crystallographic study and density functional theory calculations on 54 at the B3LYP/6‐31G(d) level of theory indicate a significant distortion in planarity of the aromatic ring. Glutathione peroxidase‐like activities of diselenides 46 and 47 and their selenenate esters 56 and 57 have been studied both by thiophenol and bioassay methods. The very low glutathione peroxidase‐like activity of the diselenides (46 and 47) and their selenenate esters (56 and 57) in the thiophenol assay is attributed to the presence of the relatively strong Se⋅⋅⋅O intramolecular interaction in the selenenyl sulfide intermediates. The interaction retards the catalytic activity through both thiol exchange and an intramolecular cyclization reaction.
[FeIII(F20‐tpp)Cl] Is an Effective Catalyst for Nitrene Transfer Reactions and Amination of Saturated Hydrocarbons with Sulfonyl and Aryl Azides as Nitrogen Source under Thermal and Microwave‐Assisted Conditions
Authors: Liu Yungen , Che Chi‐Ming
Published: July 2010

[FeIII(F20‐tpp)Cl] (F20‐tpp=meso‐tetrakis(pentafluorophenyl)porphyrinato dianion) is an effective catalyst for imido/nitrene insertion reactions using sulfonyl and aryl azides as nitrogen source. Under thermal conditions, aziridination of aryl and alkyl alkenes (16 examples, 60–95 % yields), sulfimidation of sulfides (11 examples, 76–96 % yields), allylic amidation/amination of α‐methylstyrenes (15 examples, 68–83 % yields), and amination of saturated CH bonds including that of cycloalkanes and adamantane (eight examples, 64–80 % yields) can be accomplished by using 2 mol % [FeIII(F20‐tpp)Cl] as catalyst. Under microwave irradiation conditions, the reaction time of aziridination (four examples), allylic amination (five examples), sulfimidation (two examples), and amination of saturated CH bonds (three examples) can be reduced by up to 16‐fold (24–48 versus 1.5–6 h) without significantly affecting the product yield and substrate conversion.
Coordination‐Induced Spin Crossover (CISCO) through Axial Bonding of Substituted Pyridines to Nickel–Porphyrins: σ‐Donor versus π‐Acceptor Effects
Authors: Thies Steffen , Bornholdt Claudia , Köhler Felix , Sönnichsen Frank D. , Näther Christian , Tuczek Felix , Herges Rainer
Published: July 2010

Nickel‐porphyrins, with their rigid quadratic planar coordination framework, provide an excellent model to study the coordination‐induced spin crossover (CISCO) effect because bonding of one or two axial ligands to the metal center leads to a spin transition from S=0 to S=1. Herein, both equilibrium constants K1S and K2, and for the first time also the corresponding thermodynamic parameters ΔH1S, ΔH2, ΔS1S, and ΔS2, are determined for the reaction of a nickel‐porphyrin (Ni‐tetrakis(pentafluorophenyl)porphyrin) with different 4‐substituted pyridines by temperature‐dependent NMR spectroscopy. The association constants K1S and K2 are correlated with the basicity of the 4‐substituted pyridines (R: OMe>H>CO2Et>NO2) whereas the ΔH1S values exhibit a completely different order (OMeCO2Et>NO2). 4‐Nitropyridine exhibits the largest binding enthalpy, which, however, is overcompensated by a large negative binding entropy. We attribute the large association enthalpy of nitropyridine with porphyrin to the back donation of electrons from the Ni dxz and dyz orbitals into the π orbitals of pyridine, and the negative association entropy to a decrease in vibrational and internal rotation entropy of the more rigid porphyrin–pyridine complex. Back donation for the nitro‐ and cyanopyridine complexes is also confirmed by IR spectroscopy, and shows a shift of the N–O and C–N vibrations, respectively, to lower wave numbers. X‐ray structures of 2:1 complexes with nitro‐, cyano‐, and dimethylaminopyridine provide further indication of a back donation. A further trend has been observed: the more basic the pyridine the larger is K1S relative to K2. For nitropyridine K2 is 17 times larger than K1S and in the case of methoxypyridine K2 and K1S are almost equal.
Periodic Mesoporous Organosilica (PMO) Materials with Uniform Spherical Core‐Shell Structure
Authors: Haffer Stefanie , Tiemann Michael , Fröba Michael
Published: July 2010

We report the synthesis of monodisperse, spherical periodic mesoporous organosilica (PMO) materials. The particles have diameters between about 350 and 550 nm. They exhibit a regular core‐shell structure with a solid, non‐porous silica core and a mesoporous PMO shell with a thickness of approximately 75 nm and uniform pores of about 1.7 nm. The synthesis of the core and the shell is carried out in a one‐pot, two‐stage synthesis and can be accomplished at temperatures between 25 and 100 °C. Higher synthesis temperatures lead to substantial shrinking of the solid core, generating an empty void between core and shell. This leads to interesting cavitation phenomena in the nitrogen physisorption analysis at 77.4 K.
Proaromaticity: Organic Charge‐Transfer Chromophores with Small HOMO–LUMO Gaps
Authors: Wu Yi‐Lin , Bureš Filip , Jarowski Peter D. , Schweizer W. Bernd , Boudon Corinne , Gisselbrecht Jean‐Paul , Diederich François
Published: July 2010

Novel donor‐ and/or acceptor‐substituted cross‐conjugated carbocycles based on quinoids or expanded quinoids, with radiaannulene perimeters, were prepared and investigated to validate proaromaticity as a concept for reducing HOMO–LUMO gaps in push–pull chromophores. Analyses of IR, 1H NMR, and UV/Vis/NIR spectra in conjunction with molecular structures determined by X‐ray diffraction show that these push–pull quinoids have significant charge‐separated ground states. This feature results in small optical gaps (near IR region) and diatropic magnetic environments inside the carbocycles, as suggested by nucleus‐independent chemical shift (NICS) calculations. The NICS results, together with the bond‐length analysis of the quinoid spacers, provide strong support that proaromaticity, that is, aromatized zwitterionic mesomeric contributions in the ground state, is effective. A push–pull tetrakis(ethynediyl)‐expanded quinoid chromophore represents the first proaromatic radiaannulene.
Nanostructure‐Directed Physisorption vs Chemisorption at Semiconductor Interfaces: The Inverse of the HSAB Concept
Authors: Gole James L. , Ozdemir Serdar
Published: July 2010

A concept, complementary to that of hard and soft acid–base interactions (HSAB‐dominant chemisorption) and consistent with dominant physisorption to a semiconductor interface, is presented. We create a matrix of sensitivities and interactions with several basic gases. The concept, based on the reversible interaction of hard‐acid surfaces with soft bases, hard‐base surfaces with soft acids, or vice versa, corresponds 1) to the inverse of the HSAB concept and 2) to the selection of a combination of semiconductor interface and analyte materials, which can be used to direct a physisorbed vs chemisorbed interaction. The technology, implemented on nanopore coated porous silicon micropores, results in the coupling of acid–base chemistry with the depletion or enhancement of majority carriers in an extrinsic semiconductor. Using the inverse‐HSAB (IHSAB) concept, significant and predictable changes in interface sensitivity for a variety of gases can be implemented. Nanostructured metal oxide particle depositions provide selectivity and complement a highly efficient electrical contact to a porous silicon nanopore covered microporous interface. The application of small quantities (much less than a monolayer) of nanostructured metals, metal oxides, and catalysts which focus the physisorbtive and chemisorbtive interactions of the interface, can be made to create a range of notably higher sensitivities for reversible physisorption. This is exemplified by an approach to reversible, sensitive, and selective interface responses. Nanostructured metal oxides developed from electroless gold (AuxO), tin (SnO2), copper (CuxO), and nickel (NiO) depositions, nanoalumina, and nanotitania are used to demonstrate the IHSAB concept and provide for the detection of gases, including NH3, PH3, CO, NO, and H2S, in an array‐based format to the sub‐ppm level.
Doped TiO2 and TiO2 Nanotubes: Synthesis and Applications
Authors: Nah Yoon‐Chae , Paramasivam Indhumati , Schmuki Patrik
Published: July 2010

TiO2 is one of the most investigated compounds in contemporary materials science. Due to a set of virtually unique electronic properties, it finds intense use in photoelectrochemical applications such as photocatalysis or solar cells. The main drawback in view of direct exploitation of solar‐light‐based effects is its large band gap of >3 eV. Visible‐light‐activated TiO2 can be prepared by doping (band‐gap engineering) through incorporation or decoration with other metal ions, nonmetal ions, and semiconductors. Most recently, efforts in TiO2 research have been even more intensified by the finding of self‐organized nanotubular oxide architectures that can be prepared by a simple but optimized anodization of Ti metal surfaces. These nanotubular geometries provide large potential for enhanced and novel functional features. This Review examines doped TiO2 and in particular TiO2 nanotubes. Various types of dopants, doping methods, and applications of modified TiO2 nanotubes are discussed.
FcγRIIB regulation of BCR/TLR‐dependent autoreactive B‐cell responses
Authors: Avalos Ana M. , Uccellini Melissa B. , Lenert Petar , Viglianti Gregory A. , Marshak‐Rothstein Ann
Published: July 2010

Crosslinking of Fc γ receptor II B (FcγRIIB) and the BCR by immune complexes (IC) can downregulate antigen‐specific B‐cell responses. Accordingly, FcγRIIB deficiencies have been associated with B‐cell hyperactivity in patients with systemic lupus erythematosus and mouse models of lupus. However, we have previously shown that murine IgG2a‐autoreactive AM14 B cells respond robustly to chromatin‐associated IC through a mechanism dependent on both the BCR and the endosomal TLR9, despite FcγRIIB coexpression. To further evaluate the potential contribution of FcγRIIB to the regulation of autoreactive B cells, we have now compared the IC‐triggered responses of FcγRIIB‐deficient and FcγRIIB‐sufficient AM14 B cells. We find that FcγRIIB‐deficient cells respond significantly better than FcγRIIB‐sufficient cells when stimulated with DNA IC that incorporate low‐affinity TLR9 ligand (CG‐poor dsDNA fragments). AM14 B cells also respond to RNA‐associated IC through BCR/TLR7 coengagement, but such BCR/TLR7‐dependent responses are normally highly dependent on IFN‐α costimulation. However, we now show that AM14 FcγRIIB−/− B cells are very effectively activated by RNA IC without supplemental IFN‐α priming. These results demonstrate that FcγRIIB can effectively modulate both BCR/TLR9 and BCR/TLR7 endosomal‐dependent activation of autoreactive B cells.
Increased CD127 expression on activated FOXP3+CD4+ regulatory T cells
Authors: Simonetta Federico , Chiali Amel , Cordier Corinne , Urrutia Alejandra , Girault Isabelle , Bloquet Stéphane , Tanchot Corinne , Bourgeois Christine
Published: July 2010

Regulatory T cells (Treg) are commonly identified by CD25 (IL‐2Rα) surface expression and/or intracellular expression of the FOXP3 transcription factor. In addition, Treg are also characterized by low CD127 (IL‐7Rα) expression when compared to conventional T cells and their biology in the periphery is considered essentially independent of IL‐7. We further investigated CD127 expression on Treg and we demonstrated differential CD127 expression depending on Treg subsets considered. Notably, we observed high CD127 expression on inducible costimulatory molecule (ICOS)‐ and CD103‐expressing Treg subsets. Since these two markers reflect activation status, we addressed whether Treg activation modulated CD127 expression. We demonstrated that in contrast to conventional T cells, Treg significantly upregulated CD127 expression during in vitro and in vivo activation using adoptive transfer and contact dermatitis models. High CD127 expression on Treg was also predominantly detected ex vivo in some specific sites, notably bone marrow and skin. Importantly, higher CD127 expression on Treg correlated with higher phosphorylation of STAT5 upon IL‐7 exposure. High CD127 expression on Treg also provided survival advantage upon in vitro incubation with IL‐7. We thus demonstrated that low CD127 expression is not an intrinsic characteristic of Treg and we identified activated Treg as a potential target of endogenous or therapeutic IL‐7.
Rhamnolipids: Production in bacteria other than Pseudomonas aeruginosa
Authors: Toribio Jeiry , Escalante Ana E. , Soberón‐Chávez Gloria
Published: July 2010

Rhamnolipids produced by Pseudomonas aeruginosa are the most studied biosurfactants due to their potential applications in a wide variety of industries and the high levels of their production. However, even though these biosurfactants are already produced at an industrial scale, the fact that P. aeruginosa is an opportunistic pathogen impose a restriction for its large scale production due to the intrinsic health hazard of the process. Other bacterial species that have been reported to be rhamnolipid producers are the pathogens Burkholderia mallei and B. pseudomallei, and recently the non‐pathogenic B. thailandensis. This short review presents information on rhamnolipid production by bacteria different from P. aeruginosa, as well as some approaches that have been taken to produce rhamnolipids using non‐pathogenic bacteria by genetic engineering of different bacteria. The low frequency of occurrence of rhamnolipid production among natural isolates that are not P. aeruginosa or Burkholderia, as well as the absence of orthologs of the genes involved in rhamnolipid synthesis (rhl genes) among the hundreds of sequenced bacterial genomes, suggest that the rare reported cases of these type of rhamnolipid‐producing bacteria have acquired this trait through horizontal gene transfer either from P. aeruginosa or from a member of Burkholderia.
Fish oil – from the bad and the ugly to the precious and good
Authors: Bockisch Michael
Published: July 2010

Fish oil has since long been one of the basic nutrients for many people in the far northern hemisphere. When ships began to travel the open oceans independent from weather conditions, fish oil became a cheap replacement for vegetable oils in many products. Native fish oil was mainly consumed for its vitamin content, as its sensory quality could not match any consumer expectation. The development in medical and nutritional science made the close relationship between health and long chain polyunsaturated fatty acids more apparent. First findings evolved half a decade ago from observations with Greenland Inuit. These findings were mainly used to make a link between fatty acids and cardiovascular diseases. Recent research widened the scope and marine ω‐3 fatty acids are given a big potential to improve individual and public health.
Aromatic plants in alcoholic beverages. A review.
Authors: Tonutti Ivan , Liddle Peter
Published: July 2010

The use of aromatic plants and spices to prepare beverages dates back to ancient Mediterranean history. This article presents a non‐exhaustive overview of the historical and current use of some botanicals in the aromatization of different types of alcoholic beverages, including some legislative aspects. Copyright © 2010 John Wiley & Sons, Ltd.
The oldest record of Eothinoceratidae (Ellesmerocerida, Nautiloidea): Middle Tremadocian of the Cordillera Oriental, NW Argentina
Authors: Cichowolski Marcela , Vaccari N. Emilio
Published: July 2010

Middle Tremadocian cephalopods from the Sierra de Mojotoro, Cordillera Oriental, NW Argentina, are assigned to Saloceras cf. sericeum (Salter) based on the siphuncle morphology and general shape of the conch. Saloceras sericeum (Salter) is known from the Upper Tremadocian and Floian of England and Wales, a region that formed part of eastern Avalonia during the Early Ordovician, located at a high southern latitude to the north of the Gondwanan margin. This is the oldest record of this genus and of the family Eothinoceratidae, and extends the geographical range of Saloceras, being the first positive record of its presence in Argentina and the Central Andean Basin. These remains are amongst the oldest cephalopods described from NW Argentina. They represent the third mid Tremadocian record of nautiloids at relatively high palaeolatitudes and away from the low latitude carbonate platform palaeoenvironments where the bulk of the earliest cephalopods resided. Copyright © 2010 John Wiley & Sons, Ltd.
The geography of hospital admission in a national health service with patient choice
Authors: Fabbri Daniele , Robone Silvana
Published: July 2010

Each year about 20% of the 10 million hospital inpatients in Italy get admitted to hospitals outside the Local Health Authority of residence. In this paper we carefully explore this phenomenon and estimate gravity equations for ‘trade’ in hospital care using a Poisson pseudo‐maximum likelihood method. Consistency of the PPML estimator is guaranteed under the null of independence provided that the conditional mean is correctly specified. In our case we find that patients' flows are affected by network autocorrelation. We correct for it by relying upon spatial filtering. Our results suggest that the gravity model is a good framework for explaining patient mobility in most of the examined diagnostic groups. We find that the ability to restrain patients' outflows increases with the size of the pool of enrollees. Moreover, the ability to attract patients' inflows is reduced by the size of pool of enroless for all LHAs except for the very big LHAs. For LHAs in the top quintile of size of enrollees, the ability to attract inflows increases with the size of the pool. Copyright © 2010 John Wiley & Sons, Ltd.
SEVIS: The impact of homeland security on American colleges and universities
Authors: Danley Janet V.
Published: July 2010

The SEVIS program, one component of the federal guidelines for homeland security, continues to affect higher education institutions.