bluuebunny/crossref_metadata_2025_split huggingface dataset:
Genetically Engineered Chimeric Silk–Silver Binding Proteins
Authors: Currie Heather A. , Deschaume Olivier , Naik Rajesh R. , Perry Carole C. , Kaplan David L. 
Published: May 2011

AbstractComposite or hybrid materials are commonly found in Nature, formed through the concentration and subsequent nucleation of ions upon organic templates that are most often protein based. Examples include the deposition of calcium containing salts in bone, teeth and the inner ear and iron oxide structures in magnetotactic bacteria. Biological organisms use a limited number of metal ions, the principal ones being calcium and iron, with lesser amounts of strontium, and barium. The ability to utilize other ions to generate composites offers the possibility of new material properties. New materials incorporating silver would be useful in the context of antimicrobial functions. Therefore, in the present study, a new route to such functionalized biomaterials is reported. Genetically engineered fusion proteins are created by the incorporation of nucleotides corresponding to short silver binding peptides identified by a combinatorial biopanning process into the consensus sequence of silk from the spider, Nephila clavipes. The resulting chimeric silk–silver binding proteins nucleated Ag ions from a solution of silver nitrate while the silk protein provided a stable template material which could be processed into films, fibers, and three‐dimensional scaffolds. The silk films inhibited microbial growth of both Gram‐positive and Gram‐negative microrganisms on agar plates and in liquid culture, thus highlighting the potential of these chimeric material systems as antimicrobial biomedical coatings.
A Highly Efficient Electrochemical Biosensing Platform by Employing Conductive Nanocomposite Entrapping Magnetic Nanoparticles and Oxidase in Mesoporous Carbon Foam
Authors: Kim Moon Il , Ye Youngjin , Won Byoung Yeon , Shin Sujeong , Lee Jinwoo , Park Hyun Gyu 
Published: May 2011

AbstractA conductive multi‐catalyst system consisting of Fe3O4 magnetic nanoparticles (MNPs) and oxidative enzymes co‐entrapped in the pores of mesoporous carbon is developed as an efficient and robust electrochemical biosensing platform. The construction of the nanocomposite begins with the incorporation of MNPs by impregnating Fe(NO3)3 on a wall of mesoporous carbon followed by heat treatment under an Ar/H2 atmosphere, which results in the formation of magnetic mesoporous carbon (MMC). Glucose oxidase (GOx) is subsequently immobilized in the remaining pore spaces of the MMC by using glutaraldehyde crosslinking to prevent enzyme leaching from the matrix. H2O2 generated by the catalytic action of GOx in proportion to the amount of target glucose is subsequently reduced into H2O by the peroxidase mimetic activity of MNPs generating cathodic current, which can be detected through the conductive carbon matrix. To develop a robust and easy‐to‐use electrocatalytic biosensing platform, a carbon paste electrode is prepared by mechanically mixing the nanocomposite or MMCs and mineral oil. Using this strategy, H2O2 and several phenolic compounds are amperometrically determined employing MMCs as peroxidase mimetics, and target glucose was successfully detected over a wide range of 0.5 × 10−3 to 10 × 10−3 M, which covers the actual range of glucose concentration in human blood, with excellent storage stability of over two months at room temperature. Sensitivities of the biosensor (19 to 36 nA mM−1) are about 7–14 times higher than that of the biosensor using immobilized GOx in mesoporous carbon without MNPs under optimized condition. The biosensor is of considerable interest because of its potential for expansion to any oxidases, which will be beneficial for use in practical applications by replacing unstable organic peroxidase with immobilized MNPs in a conductive carbon matrix.
Colloidal Synthesis of Ultrathin Two‐Dimensional Semiconductor Nanocrystals
Authors: Son Jae Sung , Yu Jung Ho , Kwon Soon Gu , Lee Jihwa , Joo Jin , Hyeon Taeghwan 
Published: May 2011

Abstract2D semiconductor quantum wells have been recognized as potential candidates for various quantum devices. In quantum wells, electrons and holes are spatially confined within a finite thickness and freely move in 2D space. Much effort has focused on shape control of colloidal semiconductor nanocrystals (NCs), and synthesis of 2D colloidal NCs has been achieved very recently. Here, recent advances in colloidal synthesis of uniform and ultrathin 2D CdSe NCs are highlighted. Structural and optical property characterization of these quantum‐sized 2D CdSe NCs is discussed. Additionally, 2D CdSe NCs doped with Mn2+ ions for dilute magnetic semiconductors (DMS) are presented. These 2D CdSe‐based NCs can be used as model systems for studying quantum‐well structures.
Rett syndrome: A study of the face
Authors: Allanson Judith E. , Hennekam Raoul C.M. , Moog Ute , Smeets Eric E. 
Published: May 2011

AbstractRett syndrome is a unique disorder of neurodevelopment that is characterized by an evolving behavioral and developmental phenotype, which emerges after an apparently normal early infantile period. It almost exclusively affects females. The face of Rett syndrome is said to resemble that of Angelman syndrome, although there seems little objective support for this impression and it is not a concept with universal support. This observational and anthropometric study was carried out to define the key facial characteristics of females with Rett syndrome and to evaluate whether any changes of significance occur with age. Thirty‐seven affected Caucasian females, from 2 to 20 years of age, were evaluated. Thirty‐five of them had a documented mutation in MECP2 while the remaining two fulfilled the clinical criteria for Rett syndrome and had been diagnosed by an experienced clinician. Few unusual facial features were noted. Almost all facial measurements were within the normal range although head circumference tended to fall below the normal range with increasing age. The pattern of measurements was constant over time, with the exception of increased facial width in the under 3‐year‐old girls. The face of Rett syndrome does not demonstrate marked prognathism, wide mouth, spaced teeth or striking microcephaly, all features of Angelman syndrome. Thus, while Rett and Angelman syndromes have similar clinical, neurological, and behavioral phenotypes, they do not appear to share similar facial features. © 2011 Wiley‐Liss, Inc.
The 3q29 microdeletion syndrome: Report of three new unrelated patients and in silico “RNA binding” analysis of the 3q29 region
Authors: Dasouki Majed J. , Lushington Gerald H. , Hovanes Karine , Casey James , Gorre Mereceds 
Published: May 2011

AbstractThe human 3q29 microdeletion syndrome is associated with mild facial dysmorphism, developmental delay and variable congenital malformations. We report three new unrelated patients with this syndrome. We also performed in silico RNA binding analysis in silico on the 3q29 critical region genes. Several genes within this genomic region including DLG1 and RNF168 are predicted to bind RNA. While recessive mutations in RNF168 cause RIDDLE syndrome, an immune deficiency and radiosensitivity disorder, the potential impact of heterozygous deletion of RNF168 on patients with the 3q29 deletion syndrome is still unknown. © 2011 Wiley‐Liss, Inc.
A 10.46 Mb 12p11.1–12.1 interstitial deletion coincident with a 0.19 Mb NRXN1 deletion detected by array CGH in a girl with scoliosis and autism
Authors: Soysal Yasemin , Vermeesch Joris , Davani Nooshin Ardeshir , Hekimler Kuyaş , İmirzalıoğlu Necat 
Published: May 2011

AbstractWe present a 12‐year‐old girl with de novo karyotype 46,XX,del(12)(p11.1p12.1). Array CGH revealed in addition to a 10.466 Mb interstitial deletion on 12p11.1→12p12.1 a 0.191 Mb deletion on 2p16.3. The girl presented with mild facial dysmorphism consisting of microcephaly, hypertelorism, downslanting palpebral fissures, strabismus, broad nasal base, bulbous nose, short philtrum, micro/retrognathia, irregular tooth arrangement, phalangeal deformity in distal phalanges of hands, 5th finger camptodactyly, brachydactyly in feet, history of joint hypermobility, and scoliosis. She was considered to have mild to moderate mental retardation and ascertained for an autism spectrum disorder(ASD). Short arm of chromosome 12 interstitial deletions are rarely reported whereas point mutations and deletions of NRXN1, which is located on chromosome 2p16.3, are associated with ASDs. In this article we present and discuss the phenotypic consequences of a patient who was affected by deletions of two different chromosomal regions. © 2011 Wiley‐Liss, Inc.
Bestimmung der Struktur, Zusammensetzung und Dynamiken molekularer Oberflächen unter Reaktionsbedingungen bei hohen Drücken und an der Fest‐flüssig‐Phasengrenzfläche
Authors: Somorjai Gabor A. , Beaumont Simon K. , Alayoglu Selim 
Published: May 2011

AbstractIn den letzten zwanzig Jahren wurden Experimente und Methoden zur Erforschung von Oberflächenphänomenen entwickelt, die Informationen auf molekularer Ebene bei Reaktionsbedingungen unter hohen Drücken (d. h. ungefähr 1 bar) an Fest‐flüssig‐Grenzflächen liefern. Dieser Kurzaufsatz beschreibt die Ergebnisse dieser Studien, die durch oberflächenempfindliche Laser‐Spektroskopie, Rastertunnelmikroskopie und Röntgenspektroskopie erhalten wurden. Die Verwendung von Modelloberflächen, Einkristallen sowie monodispersen Nanopartikeln mit variabler Größe (1–10 nm) und Form erleichtert die Interpretation der experimentellen Daten. Die verwendeten Methoden ermöglichen die Untersuchung der Molekularstruktur von Zwischenprodukten, des Oxidationszustandes von Metallen und der Beweglichkeit adsorbierter Moleküle. Auch werden neue Techniken diskutiert, die bedeutende Beiträge zur Untersuchung von Oberflächen unter Reaktionsbedingungen erwarten lassen.
Observation of Global Stratospheric Ozone Change
Authors: Stolarski Richard S. 
Published: May 2011

AbstractMeasurements of the total column amount of ozone from the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus 7 satellite have now been made for 13 years. They show that the 1991 Antarctic ozone hole again had a pronounced minimum in early October; making four of the last five years with deep ozone holes. Global scale measurements by TOMS show no trend in total ozone near the equator, but a significant trend at northern middle and high latitudes. This trend has a pronounced seasonal variation with maximum in winter. The observed trend is significantly larger than the predictions of gas‐phase photochemical models.
Long‐Term Study of Tropospheric and Stratospheric Ozone Changes over Berlin
Authors: Furrer R. 
Published: May 2011

AbstractLong‐term measurements of ozone concentration in the vicinity of the city of Berlin have been performed by the “Deutscher Wetterdienst” in Tempelhof, Potsdam and Lindenberg with ground based Dobson spectrophotometers and balloon borne systems for the past 24 years. — The analysis shows an increase of ozone concentration in the middle stratosphere (below 31 km height) as well as in the tropopshere. On the contrary, ongoing ozone depletion in the lower stratosphere became evident. — This large scale vertical redistribution of ozone in the troposphere and the lower stratosphere is in agreement with model calculations and trend predictions based on changes of the chemical composition and the ozone photochemistry due to anthropogenically induced tracer gas concentrations.
Column Amounts and Some Information on the Vertical Distribution of Trace Gases in the Late North Polar Winter 1990
Authors: Adrian G. P. , Blumenstock T. , Fischer H. , Frank E. , Gulde T. , Oelhaf H. , Thomas P. , Trieschmann O. 
Published: May 2011

AbstractDuring two field campaigns in the late north polar winter 1990, two Fourier transform infrared spectrometers were employed from the ground to investigate the chemical composition of the upper troposphere and stratosphere by determining zenith column amounts of the trace gases N2O, CH4, HCl, HF, HNO3, O3, and NO2. The spectrometers employed were the MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), which was operating in Esrange, North Sweden (68°N, 21°E) from January 27 to March 31, 1990, and a modified BOMEM‐DA2, which was operating in Ny Aalesund, Spitsbergen (79°N, 12°E) from March 13 to April 24, 1990 with an unapodized spectral resolution of 0.015 cm−1 and 0.010 cm−1, respectively. From the interferograms, recorded by co‐adding during an integration time of less than 15 min, spectra were calculated by correction of the phase error and a standard Fourier transformation. Synthetic spectra were simulated using the SCAIS level‐by‐level and line‐by‐line algorithm and fitted to the measured ones by scaling the first guess mixing ratio profiles of the investigated gases. Model atmospheres for each day of measurement were built up from radiosonde data and ozone soundings and were used for the simulations. Finally, the gas amounts along the vertical path were integrated from the scaled profiles. Some information on the vertical distribution of the trace gases could be obtained from fitting the shapes of the spectral lines for N2O and HCl. Both the derived integrated zenith column amounts and the low resolved vertical distributions are interpreted in terms of dynamical as well as chemical processes. During the late winter 1990, periods of strongly perturbed stratospheric chemistry have been identified. Our results indicate evident similarities to ground based Antarctic measurements reported by other groups, but distinct differences regarding the behaviour of HNO3. Further understanding of the stratospheric situation is provided by an investigation of the time history of the air masses sampled with the help of the backward trajectory analysis.
Gaseous Sulfuric Acid and Sulfur Dioxide Measurements in the Arctic Troposphere and Lower Stratosphere: Implications for Hydroxyl Radical Abundances
Authors: Möhler O. , Arnold F. 
Published: May 2011

AbstractMeasurements of gaseous sulfuric acid and sulfur dioxide were made in the winter arctic troposphere and lower stratosphere, using aircraft‐borne mass spectrometers. The measurements, covering altitudes between 3.5 and 11.4 km, took place on 14 and 18 February, 1987 in Northern Scandinavia. Our mean measured H2SO4‐concentrations are around 1.0–3.0 · 105 cm−3 and the measured SO2‐volume mixing ratios are around 50–400 pptV in the troposphere and decrease steeply above the tropopause to about 10 pptV. The combined H2SO4‐ and SO2‐measurements offer an interesting opportunity to infer hydroxyl radical concentrations. Inferred OH‐concentrations are around 0.1–1.0 · 105 cm−3, roughly consistent with model predictions.
Comparison of the Tropospheric Concentration of OH with Model Calculations
Authors: Poppe D. , Wallasch M. , Zimmermann J. , Doru H. P. , Ehhalt D. H. 
Published: May 2011

AbstractThe influence of chemical precursors and sunlight on the atmospheric OH abundance is investigated by a comparison of measured tropospheric OH with model calculations. The latter are based on the gas phase reaction mechanism of the Regional Acid Deposition Model (RADM2) which incorporates an explicit inorganic and a comprehensive organic chemistry. For rural environments in Deuselbach and Schauinsland with a low burden of hydrocarbons and nitrogen oxides the calculated and measured OH‐concentrations correlate well. The model overpredicts OH by about 10%. Under more polluted conditions in Jülich the correlation coefficient between experimental and modeled data are significantly smaller. On the average the model overpredicts OH concentrations by a factor of 1.8. Possible reasons are the influence of not measured precursors, for example isoprene, and the inapplicability of a quasi steady state model under the spatially inhomogeneous conditions in Jülich.
Ground Based Measurements of Atmospheric Gases by Spectroscopic Methods
Authors: Schiff H. I. 
Published: May 2011

AbstractSpectroscopic methods afford a number of advantages for making atmospheric measurements. It is a passive technique which is capable of making real time, in situ measurements. Since each molecules has a characteristic spectrum it is possible to make simultaneous measurement of a number of species. In addition, unequivocal identification of the target species is possible if the instrument has sufficient spectral resolution. Detection limits as low as 1 part in 1013 have been reported as well as dynamic ranges as high as 108. Temporal resolution of fractions of a second can be achieved for “eddy correlation” flux measurements. – Fourier Transform Infrared Spectroscopy (FTIR) is, perhaps, the most universal method and is particularly useful in identifying new species in heavily polluted air. However, it lacks the sensitivity required for measurements of trace gases in clean air. Differential Optical Absorption Spectroscopy (DOAS) operates in the visible and the near UV which limits the number of measurable species. But it is capable of measuring highly reactive gases such as OH, NO3, and HONO. Tunable Diode Laser Absorption Spectroscopy (TDLAS) has very high spectral resolution, sensitivity and time response. Its main disadvantage is the need for a number of laser diodes to cover a wide spectral range. Laser Induced Fluorescence (LIF) is also capable of both high sensitivity and specificity. However, rather complex excitation sources have to be devised for each gas being investigated. Photoacoustic Absorption Spectroscopy (PAS) is, in principle very simple and capable of simultaneous measurements. In practice, however, it suffers from lack of resolution and serious interferences from CO2 and H2O.
Photoacoustic Air Pollution Monitoring with an Isotopic CO2 Laser
Authors: Trushin S. A. 
Published: May 2011

AbstractThis paper considers the possibilities of using lasers based on rare isotopic species of carbon dioxide to detect trace quantities of pollutants in ambient air by photoacoustic spectroscopy (PA). The use of isotopic CO2‐laser lines allows to overcome the background absorption of atmospheric carbon dioxide. The effect of water vapor continuum absorption is eliminated by decreasing the gas pressure in the PA cell. The spectroscopic analysis performed within the framework of GEISA‐84. Database shows that even at a 10%‐measurement error detection sensitivities of 0.1–10 ppbV for NH3, C2H4, O3, HNO3, PH3 and ClO in ambient air can be achieved. A simple PA gas analyzer on the basis of a 13C16O2‐laser with a NH3 sensitivity of ≠1 ppbV and a time resolution of 1.5 min is also described.
Maximum Supercooling of H2SO4Acid Aerosol Droplets
Authors: Luo B. P. , Peter Th. , Crutzen P. J. 
Published: May 2011

AbstractHeterogeneous reactions which take place on solid polar stratospheric cloud (PSC) particles and lead to ClOxactivation, have been identified as crucial to polar ozone destruction. Scientific attention is currently focussed on whether similar heterogeneous reactions can also take place on sulfuric acid aerosol droplets. We present theoretical calculations of the homogeneous freezing of sulfuric acid droplets under stratospheric conditions, based on classical theory and using the best available thermodynamical data for the H2SO4–H2O system. For small cooling rates we find that most of the aerosol droplets will freeze as sulfuric acid tetrahydrate (SAT) at about 200 K, whereas for large cooling rates (e. g. in lee waves) large amounts of the aerosol droplets will stay liquid through temperatures as low as 190 K, at which point they freeze as water ice.
Stratospheric Aerosol Increases and Ozone Destruction: Implications from Mass Spectrometer Measurements
Authors: Arnold Frank 
Published: May 2011

AbstractStratospheric aerosol increases set the stage for increased halogen‐catalyzed ozone destruction. Most striking examples are polar stratospheric aerosols, so called polar stratospheric clouds (PSC's) and volcanic eruption clouds. Balloon‐ and rocket‐borne mass spectrometer measurements made by our reserach group have offered interesting new insights into these aerosol clouds. The present paper investigates, in the light of these measurements, the formation and role of the most common type of PSC's and volcanic eruption clouds. It is concluded that PSC's are mostly formed by nitric acid nucleation and/or ‐condensation leading to metastable HNO3/H2O‐condensates. In contrast, it seems that NAT (nitric acid trihydrate being the most stable HNO3/H2O‐condensate) does not form easily. The metastable condensates may be supercooled solution droplets or solid solutions, having lower existence temperatures than NAT. Volcanic H2SO4/H2O‐aerosols are formed by injection of sulfur‐bearing gases, mostly SO2, followed by photochemical conversion to gaseous H2SO4, which undergoes rapid condensation on preexisting H2SO4/H2O‐aerosols. The mass spectrometer measurements suggest that these H2SO4/H2O‐aerosols have an important role in setting the stage for halogen‐catalyzed ozone‐destruction.
LIDAR Measurements of Stratospheric Aerosols in the Arctic
Authors: Neuber R. , Beyerle G. , Schrems O. 
Published: May 2011

AbstractA LIDAR instrument is operated at Ny‐Ålesund, Spitsbergen (79N, 12E). Backscatter profiles of stratospheric aerosols like polar stratospheric clouds (PSCs) are determined at a wavelength of 353 nm. PSC data are shown for January 1989 and 1990. The data are correlated with atmospheric temperature. In August 1991 an aerosol layer was found, which presumably originates from the volcanic eruption of Mount Pinatubo. The modification of the LIDAR instrument for the European Arctic Stratospheric Ozone Expedition (EASOE) in the winter 1991/92 is presented.
A Micro‐Physical Box Model for EASOE: Preliminary Results for the January/February 1990 PSC Event over Kiruna
Authors: Peter Th. , Müller R. , Drdla K. , Petzoldt K. , Reimer E. 
Published: May 2011

AbstractFirst results of a trajectory box model designed for the European Arctic Stratospheric Ozone Experiment (EASOE) are presented. The model contains a comprehensive description of both types of polar stratospheric particles, NAT on aerosol (Type‐I) and ice on NAT (Type‐II), including nucleation, growth/evaporation, and sedimentation of particles. The performance of the model is tested for the case of the polar stratospheric cloud (PSC) event January 31–February 1, 1990 over Kiruna (north Sweden). Comparison of the model results with measurements from two stratospheric balloon flights shows that the theory can reproduce the data provided the following two conditions are satisfied: (a) a strong lee wave activity was present at the time of the ballon flights; (b) the nucleation of NAT on H2SO4 is either governed by a high barrier energy or delayed due to insufficient freezing of the background aerosol. These results indicate an urgent need for both, the implementation of lee wave effects into the existing trajectory models and a better understanding of the NAT nucleation on the background aerosol.
Photoreactivity of Molecular Aggregates
Authors: Vaida Veronica , Jefferson Anne , Rühl Eckart 
Published: May 2011

AbstractThe spectroscopy and photoreactivity of atmospheric trace gases embedded in clusters is examined in this work. Perturbations induced by intermolecular interactions are obtained in order to evaluate the role that the heterogeneous photochemistry of such species could play in the chemical balance of the atmosphere. – Spectroscopic effects are monitored using aggregates produced in supersonic jets and measured by high resolution Fourier Transform direct ultraviolet absorption techniques. These spectra are compared with those of the isolated molecule to extract shifts and intensity changes when the chromophore is clustered. Photochemical studies involve laser pump‐probe experiments with mass resolved multiphoton ionization detection. Changes in the isolated molecule photochemistry are monitored as a function of cluster formation. – This paper discusses the methodology developed as well as the specific example of clusters of ozone with atmospheric trace gases.