bluuebunny/crossref_metadata_2025 huggingface dataset:
Profile Analysis of Spectral Line by Fabry-Perot Interferometer
Authors: Tako Toshiharu , Ohi Misao
Published: March 2014

Some of problems concerning the half-width measurement in the profile analysis of a spectral line by a Fabry-Perot interferometer are discussed. The apparent line shape and its half-width are treated and the two figures showing the relations among the apparent width, apparatus width and pure line width for the Gaussian and Lorentzian line are obtained. These curves are useful for the correction of apparatus width in the Fabry-Perot interferometer. The combination of the Doppler and Lorentz type broadening is also discussed and the figures showing the relation among the Doppler, Lorentz and resulting half-width are obtained. With the aid of these curves, the unknown width can be evaluated, if the other two widths are known. These results are applied to the analysis of the 5461Å line emitted by Hg198 isotope lamps.
The Fabry-Perot Interferometer in the Middle and Vacuum Ultraviolet
Authors: Bradley D. J. , Bates B. , Juulman C. O. L. , Majumdar S.
Published: March 2014

The factors affecting the performance of Fabry-Perot interferometers in the middle and vacuum ultraviolet are considered. Improvement of performance in the middle ultraviolet to 2000Å and extension of the useful spectral domain of the instrument into the vacuum ultraviolet are reported.
The preparation and optical properties for ultraviolet multiple beam interferometry of double layer aluminium-magnesium fluoride semi-transparent reflecting coatings are discussed. Fabry-Perot type Al–MgF2 interference filters for these spectral regions are also described and an interferogram of λ 1849 of HgI obtained with an ultraviolet sensitive image converter is illustrated. Applications of these techniques to space research and to laser and plasma spectroscopy are mentioned.
Collimating Grating Monochromators for the Vacuum Ultraviolet
Authors: Bedo D. E. , Hinteregger H. E.
Published: March 2014

A non-focusing, grazing incidence monochromator which utilizes planar gratings and collimating slit systems is described. Such an instrument is capable of moderate spectral resolution in the vacuum ultraviolet and allows for relatively simple scanning mechanisms. Monochromators of this type have been built for laboratory studies and for incorporation in a satellite-borne experiment for monitoring solar intensities in the extreme ultraviolet. Measurements made on rare gas spectra indicate approximate agreement between computed and observed instrumental line widths.
An Ultraviolet Rocket Stellar Spectrometer
Authors: Jr. David U. Wright,
Published: March 2014

The Ultraviolet Rocket Spectrometer (UVR) was developed to measure stellar spectra in the wavelength interval 1100 Å to 4000 Å. The UVR consists of a 33 cm Dall-Kirkham telescope which provides input to a spectrometer utilizing a plane grating in convergent light. The f/#11.9 system is such that the apparent coma of the plane grating is compensated for by the coma of the tilted spherical spectrometer mirror. Two exit slits are located at compromise focal positions and cover the total scan of 2900 Å in two bands with a central overlap of approximately 1300 Å. Spectral scan is cam operated and grating position is indicated by a marker generator related to cam rotation. The absolute response function of the flight unit is established by the simultaneous exposure of calibrated photomultipliers (PMT) and the UVR to the same monochromatic beam of collimated light. Analyses of spectra recorded in the laboratory indicate performance consistent or better than the 3 Å equivalent width of the UVR exit slits.
An Ultraviolet Spectrophotometer for Satellite Astronomy
Authors: Hallam Kenneth , Mangus John
Published: March 2014

An astronomical Spectrophotometer is described which was designed for use on OSOB, the second U.S. Orbiting Solar Observatory. The Spectrophotometer is intended to analyze the ultraviolet emission from stars and nebulae. The entrance slit of the Spectrophotometer defines the field at the primary focus of a 6-inch modified Gregorian reflecting telescope. The secondary serves as the collimator for a rotating 1200 lines/mm plane reflection grating. Diffracted light from the grating is collected by an off-axis paraboloid and focused through the exit slit to the photomultiplier. The signal from the photomultiplier is pulse-counted and fed into the magnetic tape storage of the space-craft. The instrument utilizes the spin of the gyroscopically-stabilized satellite to sweep the 1°×0.4° over the celestial sphere. Slow precession of the spin axis allows eventual coverage of the whole sky. Ten adjacent wavelength bands of 180Å width between 1500Å and 3300Å are defined by succesive steps of the grating.
Les étincelles sous vide utilisées comme source de lumière pour l'ultraviolet lointain
Authors: Romand J.
Published: March 2014

This paper describes the work done recently about the vacuum spark light sources, designed and studied at the C.N.R.S. Bellevue, mainly concerning the continuous spectrum source.
An appreciable increase of the reproducibility of the sparks has been obtained by improving the efficiency of the triggering device, and by observing the emitting anode end-on. With low capacitance storage condensers of high performance, and using a water-cooled electrode holder, it is possible to obtain a fairly good continuous spectrum at a repetition rate of 10 to 20/sec.
Some data are given about the geometrical localisation of the continous spectrum emitting region on the anode, about the effect of the electrical parameters, and also about the spectrum observed in the x rays region.
A tentative interpretation of the continuous spectrum emission mechanism is suggested, and some examples of application in absorption spectroscopy are mentioned.
Ultraviolet Photography and Spectroscopy Using a Spectrally Selective Image Converter
Authors: Dunkelman L. , Hennes J. P.
Published: March 2014

Laboratory and space research have both benefited from the new spectrally selective ultraviolet photodetectors. Large band-gap photoemitters, such as cesium telluride, having high quantum efficiencies in the ultraviolet and very low yields at longer wavelengths are now available. An image tube with such a cathode combines the advantages of spectrally selective photoemission with the flux-integrating property of photographic emulsion. Observations can thus be made at selected ultraviolet wavelength regions, either photographically or visually, even in the presence of strong long wavelength backgrounds. Visual measurements with a Cs-Te image converter, having a sapphire faceplate and a green phosphor, were made with the following results: (a) cathode quantum efficiency is 0.016, which is expected to improve in future tubes; (b) minimal detectable converted 2537 A irradiance is 4×10-5 ergs cm-2 sec-1; and (c) tube background is undetectable. Mercury spectra obtained with this tube demonstrate the expected high rejection of visible light. Tables are included which list the brightnesses of several extended ultraviolet and visible sources of interest in the space sciences. The luminance of visible sources; the radiance of ultraviolet sources; and the relative brightness, on a photon basis, of spectrally converted ultraviolet sources along with visible sources are tabulated.
Far Infrared Reflectance Spectra and Dielectric Dispersion of a Variety of Materials Having the Perovskite and Related Structures
Authors: Perry C. H.
Published: March 2014

Many compounds possessing the perovskite and related structures exhibit unusual properties, such as ferroelectricity and antiferromagnetism. Knowledge of the nature of the interatomic forces in the crystals prove extremely useful in explaining these phenomena. Of particular interest is the temperature-dependent low frequency mode which recent theories show is responsible for the ferroelectric and antiferroelectric behavior in certain perovskite titanates, zirconates and hafnates.
The transmittance of a number of these materials has been observed from 800–50 cm-1. Reflectance measurements at room temperature have been made of a wider range in the far infrared. Two cubic perovskite fluorides are included. The data have been analyzed using the Kramers-Kronig relationship to obtain the dielectric dispersion of these materials. The resonances observed have been related to presumed normal modes of vibration of the crystals and comparison is made between the various materials.
Objectifs photographiques grand-angulaires utilisant une surface parabolique–Wide angle camera lens with parabolic surface–
Authors: Hugues Ed.
Published: March 2014

Two peculiar properties of piano-parabolic divergent lenses are at the origin of a new class of photographic objectives for 16mm and 35mm film.
1) Freedom from astigmatism for all bundles of rays from infinity (plan surface side) and for an exit pupil at infinity (parabolic surface side).
2) Correction of distorsion by a convenient choice of the refractive index.
Furthermore the increase of the apparent surface of the entrance pupil at the rim of the field enables to get a luminosity practically constant in the plan of the image. Complete data and performances of two lenses are given; one of these permits to photograph a range of the earth approximately 2000 km long from an altitude of 700 km. Il has been adopted by NASA to equip with it the meteorological satellite “TIROS.”
Far Infrared Spectroscopy of Compressed Gases Using a Michelson Interferometer
Authors: Bosomworth D. R. , Gush H. P.
Published: March 2014

The absorption coefficients of the compressed gases hydrogen, nitrogen, and a heliumargon mixture have been determined in the wave number region 20–400 cm-1. A Michelson interferometer has been used to make the measurements. Accurate absorption coefficients may be obtained using the Fourier Transform method of spectroscopy provided certain precautions are taken in the analysis. These precautions are discussed and typical absorption spectra are shown.
Modern Spectroscopy of Solids
Authors: Dexter D. L.
Published: March 2014

A qualitative review is presented of selected recent developments in the study of the optical properties of solids from the γ-ray region to the far infra-red.
Ultraviolet Absorption of Solid Deuterium
Authors: Baldini Giancarlo
Published: March 2014

The optical absorption spectrum of solid deuterium in the vacuum ultraviolet shows structure which appears to be due to transitions from the 1s2 ground state to the vibrational levels of the 1s2p excited states of the D2 molecules. Xenon and krypton diluted in solid D2 give rise to absorption lines at energies ∼0.7 eV larger than the resonance lines of the free atoms. The presence of additional structure is interpreted as being due to Wannier states of the impurities.
Optical Properties of Sodium Iodide-Thallium Crystals
Authors: Uchida Yoichi , Matsui Eiichi
Published: March 2014

The optical absorption and luminescence of sodium iodide crystals containing thallium at various concentrations have been studied. It is found that a pair of thallous ions replacing two adjacent sodium ions in the crystal has absorption bands at 305 and 310 mµ, the former exciting the 325 mµ emission band and the latter the 425 mµ emission band, all bands being measured at 77°K. Study of the polarized luminescence from these bands confirms the above-mentioned model for the double thallous ions and suggests the nature of its electronic structure.
Ultraviolet Absorption of Transition Metal Ions in Alkali-Halides
Authors: Kuwabara Goro , Aoyagi Kiyoshi
Published: March 2014

Ultraviolet absorption bands of V2+, Mn2+, Ni2+, Cu2+, Cu+, and Zn2+ in NaCl or NaF were studied. One or two strong and temperature-insensitive bands were observed for ions with partly filled 3d-shells. Two or three weak and temperature-sensitive bands were detected for all kinds of ions. The strong bands were tentatively assigned to electron transfer transitions from nonbonding orbitals of surrounding halogen ions to antibonding orbitals of a central metal ion and the weak ones to parity forbidden intraionic transitions.
Automatic Lens Design by Statistical Analysis
Authors: Brixner Berlyn
Published: March 2014

The LASL lens design technique based on a statistical analysis of the behavior of skew rays as a function of lens-parameter changes is briefly reviewed and the results of five years' experience given. Several lenses are described, along with the procedure for designing a complex lens.
Some Examples of Lens Designing by Computer
Authors: Wynne C. G.
Published: March 2014

Examples are given of the automatic improvement of the aberration correction of Optical systems by a computing machine, using methods of optimisation described in earlier papers. The examples given are (a) and f/4 lens covering ±35.4° of field, (b) a series of operations on an f/2 double-Gauss lens, showing the improvement to be achieved by using higher index glasses, and by replacing the single rear element by two single lenses, and (c) an f/0.5 lens designed for unit magnification.
Some Experiments on Automatic Optical Design
Authors: Matsui Yoshiya , Hirose Ryusho
Published: March 2014

A study is conducted in developing a process of automatic design based on the 5th order aberration theory. Relating to this study two sorts of experiments are made:
1) Three minimization methods, i.e., the steepest descent method, the method of least squares and the method of damped least squares are compared one another with the use of a simplified optical model. The last one is found as the most suitable method for the present purpose.
2) Examination is done on a reasonable way to locate the starting point of automatic design. Approximate solutions obtained by the “thin sub-system analysis” in the 3rd order region can be used successfully as the starting points. The design process is described of a Gauss-type lens after the presently proposed method.
A study of the active controlled useful load parachute systems in terms of subsystem design, test and methods
Authors: MERCAN Ümit , İNALHAN Gökhan
Published: March 2014

Taking into account the geograhy and the geostrategic location of Turkey, it has become a necessity to perform tasks which are time sensitive such as natural disaster, search and rescue and airlift of ammunition and supplies to operation zones by using unmanned parachute systems. Turkish Air Force (TURAF) Headquarters, in response to this necessity, has claimed its place in the race of possesing new generation unmanned systems and devices which are suitable for developing technology and other improvements of the era in the fields of aviation and space sciences. Within this scope, TURAF closely follows the active controlled useful load-carrying system technology which can be operated in two different options, remote controlled and autonomous, and aims to possess this technology by producing it using local means and sources.

Across the World, the system actively used for this purpose are known as Guided Precision Aerial Delivery Systems (GPADS). GPADS technology, which has not been used in Turkey yet, has been studied in detail with this thesis. In this context, a description of the concepts regarding the system TURAF needs has been made, and the technical specifications that the system on draft requires have been put forward. At the end of the study, it has been concluded that the system can be produced domestically with the cooparation of institutions and organizations in Turkey, and that the ram air canopy which produces the best flight performance results should be used during the design phase provided that the compulsory military standarts are met.
Spectral Detection of Micro-Metastases and Individual Metastatic Cells in Lymph Node Histology
Authors: Bird B. , Miljković M. , Laver N. , Diem M.
Published: March 2014

The detection of micro-metastases and individual metastatic cells in lymph node tissue by spectral methods is summarized. These methods are based on instrument-based acquisition of thousands of infrared spectra of individual tissue pixels from the tissue section, and analysis of the resulting spectral hypercube by multivariate algorithms. The method of infrared image acquisition, followed by multivariate analysis, is henceforth referred to as Spectral Histopathology (SHP). SHP produces pseudo-color images of tissue sections which reveal details that compare very favorably with images collected from hematoxylin/eosin (H & E) stained tissues in that the same tissue structures are detected. However, the infrared results are based on objective and reproducible measurements and do not depend on subjective interpretation. One of the major topics of this paper is the comparison of spectral patterns observed for the same cancer type from different patients. While this is easy in some tissue types, we found it to be difficult in tissues of very different cellularity, or tissue sections that exhibit high levels of inflammatory response. In both cases, spectral quality will be compromised due to confounding effects resulting from scattering effects. The correction of these effects now permits the direct comparison of different patient samples, and paves the way for diagnostic algorithms for cancer detection to be developed.
Detection of Cancer by Optical Analysis of Body Fluids — A Single Blind Study
Authors: AlSalhi M. , Masilamani V. , Trinka V. , Elangovan M. , Kochupillai V. , Shah N.
Published: March 2014

This paper pertains to a new technique based on fluorescence emission spectra (FES), and stokes shift spectra (SSS) of blood plasma, acetone extract of cellular fraction, and urine. These samples were collected from 60 cancer patients of different etiology and 60 age adjusted controls for a single blind study. A set of ratio parameters were obtained from the above spectra (FES and SSS of above three sets of samples), based on the relative intensity of biofluorophores like tryptophan, tyrosine, flavin etc. It was found that these biofluorophores go out of proportion for malignancy of any etiolology. The study was done in two phases: calibration and validation. Based on a certain set of ratios obtained by simple statistical analysis, in the calibration phase, the blinded samples of validation phase were spectrally analysed and classified as normal or malignant. The scoring done by independent oncologists (who were not involved in any part of this new technique) yielded an overall sensitivity of 87%, and specificity of 83%. The result indicate that new optical spectroscopic techniques could be a simple, non-invasive protocol for detection of cancers, particularly in symptomatic cases; or for monitoring the post treated cases of cancer.
Geometric Performance and Efficiency of an Optical Tracking System for Daily Pre-treatment Positioning in Pelvic Radiotherapy Patients
Authors: Li Winnie , Sie Fanny , Bootsma Gregory , Moseley Douglas , Catton Charles N. , Jaffray David A.
Published: March 2014

The purpose of this study was to characterize the accuracy of a novel in-house optical tracking system (OTS), and to determine its efficiency for daily pre-treatment positioning of pelvic radiotherapy patients compared to conventional optical distance indicator (ODI) methodology. The OTS is comprised of a passive infrared stereoscopic camera, and custom control software for use in assisting radiotherapy patient setup. Initially, the system was calibrated and tested for stability inside a radiation therapy treatment room. Subsequently, under an ethics approved protocol, the clinical efficiency of the OTS was compared to conventional ODI setup methodology through 17 pelvic radiotherapy patients. Differences between orthogonal source-to-skin distance (SSD) readings and overall set-up time resultant from both systems were compared. The precision of the OTS was 0.01 ± 0.01 mm, 0.02 ± 0.02 mm, and −0.01 ± 0.06 mm in the left/right (L/R), anterior/posterior (A/P), and cranial/caudal (C/C) directions, respectively. Discrepancies measured between the linac radiographic center in the treatment room and the calibrated origin of the camera (OTS) by two independent observers was submillimeter. Analysis of 146 fractions from 17 patients showed a high correlation between the SSD readings of the OTS and ODI setup methodologies (r = 0.99). The average time for pre-treatment positioning using the OTS couch shift calculation was 2.60 ± 0.69 minutes, and for conventional ODI setup, 3.62 ± 0.82 minutes; the difference of 1.02 minutes was statistically significant (p < 0.001). In conclusion, the OTS is a precise and robust tool for use as an independent check of treatment room patient positioning. The system is indicated as geometrically equivalent to current methods of daily pre-treatment patient positioning with potential for gains in efficiency by decreasing setup times in the treatment room.
Induction of Luciferase Activity under the Control of an hsp70 Promoter Using High-Intensity Focused Ultrasound: Combination of Bioluminescence and MRI Imaging in Three Different Tumour Models
Authors: Hundt W. , Steinbach S. , Burbelko M. , Kiessling A. , Rominger M. , O'Connell-Rodwell C. E. , Mayer D. , Bednarski M. D. , Guccione S.
Published: March 2014

The in vivo temporal changes of luciferase activity were investigated under the control of an hsp70 promoter in three tumour models after the application of different intensities of high-intensity focused ultrasound (HIFU). Three cell lines, SCCVII, NIH3T3 and M21 were stably transfected with a plasmid containing the hsp70 promoter and luciferase reporter gene, and tumours were subcutaneously initiated into mice. At a size of 1300 ± 234 mm3, the tumours were exposed to five intensities of continuous HIFU (802-1401-2157-3067-4133 W/cm2) for 20 sec. Bioluminescence and MR imaging were performed to assess luciferase activity and signal intensity changes in the tissue. The MRI scan protocol was pre- and post-contrast T1-wt-SE, T2-wt-FSE, DCE-MRI, diffusion-wt STEAM sequence, T2 relaxation time determination obtained on a 1.5-T GE MRI scanner. The NIH3T3 tumours showed the highest luciferase activity of 328.1 ± 7.1 fold at 24 h at a HIFU intensity of 3067 W/cm2, the M21 tumours of 3.2 ± 0.6 fold 8 hours and the SCCVII tumours 2.9 ± 0.9 fold 4 hours post-HIFU at 2157 W/cm2. The greatest increase in T2 signal intensity and T2 relaxation time of 20.7 ± 3.4% was seen in the SCCVII tumours. The highest contrast medium uptake of 10.1 ± 1.1% was noted in the M21 tumours, and 14.8 ± 1.9% in the SCCVII tumours. In all tumours, a significant increase in the diffusion coefficient was seen with increased HIFU intensity, the highest of which was 40.3 ± 4.1% in the SCCVII tumours. The three tumour cell lines stably transfected with the hsp70/luciferase gene showed differential luciferase activity, which peaked at different times after the application of HIFU and was dependant on tumour type and HIFU energy deposition.
Calcium carbonate dissolution in the upper 1000 m of the eastern North Atlantic
Authors: Barrett Pamela M. , Resing Joseph A. , Buck Nathaniel J. , Feely Richard A. , Bullister John L. , Buck Clifton S. , Landing William M.
Published: March 2014

Recent analyses suggest that considerable CaCO3 dissolution may occur in the upper water column of the ocean (< 1500 m). This study uses the distribution of particulate calcium from high‐resolution suspended matter sampling along the Climate Variability and Predictability/CO2 Repeat Hydrography A16N transect in 2003 to estimate CaCO3 dissolution in the top 1000 m of the North Atlantic. Dissolution rates were also approximated using changes in total alkalinity measurements along isopycnal surfaces. Water masses were found to be undersaturated with respect to aragonite at intermediate depths (400–1000 m) in the eastern tropical North Atlantic. The CaCO3 dissolution rate in this region is estimated to be 0.9 mmol CaCO3 m−2 d−1, indicating this region is a hotspot for upper water column CaCO3 dissolution compared to the Atlantic basin as a whole. Dissolution rates calculated from particulate calcium distributions outside of this region were significantly lower (0.2 mmol CaCO3 m−2 d−1) and are comparable to previous estimates of CaCO3 dissolution flux for the Atlantic Ocean. The magnitude of upper water column dissolution rates compared to measured surface ocean CaCO3 standing stocks suggests that biologically mediated CaCO3 dissolution may be occurring in the top 1000 m of the Atlantic.
Air‐sea CO2 fluxes in the California Current: Impacts of model resolution and coastal topography
Authors: Fiechter Jerome , Curchitser Enrique N. , Edwards Christopher A. , Chai Fei , Goebel Nicole L. , Chavez Francisco P.
Published: March 2014

The present study uses a suite of coupled physical‐biogeochemical model simulations at 1/3°, 1/10°, and 1/30° to assess the impact of horizontal resolution on air‐sea CO2 fluxes in the California Current System (CCS), a relevant issue for downscaling between coarser resolution global climate models and higher resolution regional models. The results demonstrate that horizontal resolution is important to reproduce the sharp transition between near‐shore outgassing and offshore absorption, as well as to resolve regions of enhanced near‐shore outgassing in the lee of capes. The width of the outgassing region is overestimated when horizontal resolution is not eddy resolving (i.e., 1/3°) but becomes more dependent on shelf topography for eddy‐resolving simulations (i.e., 1/10° and 1/30°). Enhanced near‐shore outgassing is associated with a local increase in wind‐driven upwelling in the lee of capes (i.e., expansion fans), meaning that sufficient horizontal resolution is needed both in the ocean circulation model and in the wind field forcing the model. From a global carbon budget perspective, the model indicates that biological production generates sufficient absorption within a few hundred kilometers of the coast to offset near‐shore outgassing, which is consistent with the notion that midlatitude eastern boundary current upwelling systems act both as a sink and source for atmospheric CO2. Based on the 1/30° solution, the CCS between 35 and 45 N and out to 600 km offshore is a net carbon sink of approximately 6 TgC yr−1, with the 1/10° solution underestimating this value by less than 10% and the 1/3° solution by a factor of 3.
Ecological processes dominate the 13C land disequilibrium in a Rocky Mountain subalpine forest
Authors: Bowling D. R. , Ballantyne A. P. , Miller J. B. , Burns S. P. , Conway T. J. , Menzer O. , Stephens B. B. , Vaughn B. H.
Published: March 2014

Fossil fuel combustion has increased atmospheric CO2 by ≈ 115 µmol mol−1 since 1750 and decreased its carbon isotope composition (δ13C) by 1.7–2‰ (the 13C Suess effect). Because carbon is stored in the terrestrial biosphere for decades and longer, the δ13C of CO2 released by terrestrial ecosystems is expected to differ from the δ13C of CO2 assimilated by land plants during photosynthesis. This isotopic difference between land‐atmosphere respiration (δR) and photosynthetic assimilation (δA) fluxes gives rise to the 13C land disequilibrium (D). Contemporary understanding suggests that over annual and longer time scales, D is determined primarily by the Suess effect, and thus, D is generally positive (δR > δA). A 7 year record of biosphere‐atmosphere carbon exchange was used to evaluate the seasonality of δA and δR, and the 13C land disequilibrium, in a subalpine conifer forest. A novel isotopic mixing model was employed to determine the δ13C of net land‐atmosphere exchange during day and night and combined with tower‐based flux observations to assess δA and δR. The disequilibrium varied seasonally and when flux‐weighted was opposite in sign than expected from the Suess effect (D = −0.75 ± 0.21‰ or −0.88 ± 0.10‰ depending on method). Seasonality in D appeared to be driven by photosynthetic discrimination (Δcanopy) responding to environmental factors. Possible explanations for negative D include (1) changes in Δcanopy over decades as CO2 and temperature have risen, and/or (2) post‐photosynthetic fractionation processes leading to sequestration of isotopically enriched carbon in long‐lived pools like wood and soil.
Unraveling the dynamics that scale cross‐shore headland relief on rocky coastlines: 2. Model predictions and initial tests
Authors: Limber Patrick W. , Murray A. Brad
Published: March 2014

We explore the behavior of a theoretical model of cross‐shore headland relief caused by alongshore differences in lithology and rock strength on rocky coastlines. Results address the question of why some rocky coasts exhibit frequent headland and embayment sequences while others evolve to a flat, smooth, and sandy configuration. Main model predictions are that cross‐shore headland amplitude is inversely proportional to beach sediment supply and the strength of wave energy convergence and divergence along the headland and bay, and proportional to the alongshore embayment length (or distance between headlands) and the difference between headland and bay rock strength. The coastline's initial physical properties (sea cliff height, composition, etc.) largely determine whether headlands will be persistent or transient landscape features. Model timescales over which the headland and bay reach steady state amplitude, or disappear to a flat coastline, range from 120 to 175,000 years depending on how close the initial amplitude is to steady state. In many cases, the coastline must evolve over several sea level highstands in order to reach equilibrium. A characteristic timescale (independent of initial conditions) shows that the coastline evolves most rapidly when: wave focusing is stronger; sea cliff rock is weaker or retreats faster in a given wave climate; the sea cliff retreat rate decreases rapidly as a function of beach width (i.e., the beach is very effective at dampening wave energy); and the coastline is sediment rich. Comparisons to nature suggest that our model is qualitatively capturing general rocky coastline dynamics and that modeled headland amplitudes are consistent with observed amplitudes.
Role of extreme snowfall events in interannual variability of snowfall accumulation in the western United States
Authors: Lute A. C. , Abatzoglou J. T.
Published: March 2014

Water resources in the western United States are contingent on interannual variations in snowpack. Interannual snowpack variability has been attributed to large‐scale climate patterns including the El Niño‐Southern Oscillation (ENSO), however, the contribution of snowfall frequency and extreme snowfall events to this variability are less well quantified. Long‐term records from Snowpack Telemetry and Cooperative Observer Program stations in the 11 western states were used to investigate these relationships by considering the number of snowfall days and snowfall water equivalent (SFE) of extreme snowfall events. The top decile of snowfall events contributed 20–38% of annual SFE, depending on the region. An average of 65% and 69% of the interannual variability in annual SFE was explained by snowfall days and SFE of top decile snowfall events, respectively, with extreme events being a more significant predictor at most stations. The latitudinal dipole in SFE during ENSO phases results from changes in snowfall frequency and extreme events. In the Pacific Northwest, above normal SFE during La Niña winters was a product of both larger contributions from extremes and more snowfall days, while below normal SFE during El Niño winters was primarily associated with a substantial reduction in extremes. Conversely, annual SFE during ENSO phases in the mountains of Arizona was more closely linked to fluctuations in snowfall days than extremes. Results indicate the importance of extreme snowfall events in shaping interannual variability in water resources and suggest that improved predictive ability may inform better water resource management now and in the coming decades.
Dual role of salt marsh retreat: Long‐term loss and short‐term resilience
Authors: Mariotti G. , Carr J.
Published: March 2014

Two major causes of salt marsh loss are vertical drowning, when sediment accumulation on the platform cannot keep vertical pace with sea level rise, and horizontal retreat, associated with wave‐induced marsh boundary erosion. Despite these processes having been extensively documented and modeled, it is unclear which loss modality dominates given a set of environmental parameters. A three‐point dynamic model was developed to predict marsh loss as a function of sea level rise, allochthonous sediment supply, wind regime, tidal range, and marsh bank and mudflat erodability. Marsh horizontal and vertical evolutions were found to respond in opposing ways to wave‐induced erosion processes. Marsh horizontal retreat was triggered by large mudflats, strong winds, high erodability of marsh bank and mudflat, whereas the opposite conditions acted to reduce the sediment supply to the marsh platform, promoting marsh loss to drowning. With low and moderate rates of sea level rise (∼5 mm/yr), retreat was found to be a more likely marsh loss modality than drowning. However, conditions associated with marsh retreat also increase the system resilience by transferring sediment on the marsh platform and preventing drowning. Our results suggest the use of a modular strategy for short‐term marsh management: selectively protect extensive salt marsh regions by maintaining healthy vegetation on the platform, while allowing other areas to retreat, leveraging the natural resilience embedded in the lateral loss of marsh extent.
A robust output error identifier for continuous‐time systems
Authors: Wang Lei , Ortega Romeo , Su Hongye , Liu Zhitao , Liu Xiangbin
Published: March 2014

This paper shows that the adaptive output error identifier for linear time‐invariant continuous‐time systems proposed by Bestser and Zeheb is robustvis‐à‐visfinite energy measurement noise. More precisely, it is proven that the map from the noise to the estimation error is–stable—provided a tuning parameter is chosen sufficiently large. A procedure to determine the required minimal value of this parameter is also given. If the noise is exponentially vanishing, asymptotic convergence to zero of the prediction error is achieved. Instrumental for the establishment of the results is a suitable decomposition of the error system equations that allows us to strengthen—tostrict—the well‐known passivity property of the identifier. The estimator neither requires fast adaptation, a dead‐zone, nor the knowledge of an upperbound on the noise magnitude, which is an essential requirement to prove stability of standard output error identifiers. To robustify the estimator with respect to non‐square integrable (but bounded) noises, a prediction error‐dependent leakage term is added in the integral adaptation.–stability of the modified scheme is established under a technical assumption. A simulated example, which is unstable for the equation error identifier and the output error identifier of Bestser and Zeheb, is used to illustrate the noise insensitivity property of the new scheme. Copyright © 2014 John Wiley & Sons, Ltd.
Nanopatterned Polymer Brushes for Triggered Detachment of Anchorage‐Dependent Cells
Authors: Yu Qian , Johnson Leah M. , López Gabriel P.
Published: March 2014

Surfaces modified with thermoresponsive poly(N‐isopropylacrylamide) (PNIPAAm) support mild and efficient harvesting of anchorage‐dependent cells. To enable cellular detachment, however, the surfaces must exhibit a narrow range of PNIPAAm thicknesses. In this work, this limitation is circumvented by introducing nanopatterns to grafted PNIPAAm brushes, eliminating the critical thickness requirement for cell‐culturing applications. Nanopatterned PNIPAAm surfaces are prepared using a combination of interferometric lithography (IL) and surface‐initiated polymerization. Above the lower critical solution temperature (LCST) of PNIPAAm (∼32 °C), these surfaces support the attachment and proliferation of mammalian cells (e.g., fibroblasts and endothelial cells). Below the LCST of PNIPAAm, cells readily detach from the nanopatterned PNIPAAm surfaces without influence from the period of nanopatterns, which vary between 157 ± 9 nm to 1021 ± 17 nm. Cells selectively attach and proliferate on PNIPAAm nanopatterns as compared to thick unpatterned PNIPAAm, which is further exploited to spatially direct cellular growth to generate cellular micropatterns. Nanopatterned PNIPAAm surfaces provide a unique solution to the critical thickness issue for cell harvesting and facilitate spatial control of cellular growth on surfaces.
Magnetic Core–Shell Nanocapsules with Dual‐Targeting Capabilities and Co‐Delivery of Multiple Drugs to Treat Brain Gliomas
Authors: Fang Jen‐Hung , Lai Yen‐Ho , Chiu Tsung‐Lang , Chen You‐Yin , Hu Shang‐Hsiu , Chen San‐Yuan
Published: March 2014

Lactoferrin (Lf)‐tethered magnetic double emulsion nanocapsules (Lf‐MDCs) are assembled from polyvinyl alcohol (PVA), polyacrylic acid (PAA), and iron oxide (IO) nanoparticles. The core–shell nanostructure of the Lf‐MDCs (particle diameters from 100 to 150 nm) can simultaneously accommodate a hydrophilic drug, doxorubicin (Dox), and a hydrophobic drug, curcumin (Cur), in the core and shell, respectively, of the nanocapsules for an efficient drug delivery system. The release patterns of the two drugs can be regulated by manipulating the surface charges and drug‐loading ratios, providing the capability for a stepwise adjuvant release to treat cancer cells. The results demonstrate that the dual (Dox+Cur)‐drug‐loaded nanocapsule can be effectively delivered into RG2 glioma cells to enhance the cytotoxicity against the cells through a synergistic effect. The combined targeting, i.e., magnetic guidance and incorporation of Lf ligands, of these Lf‐MDCs results in significantly elevated cellular uptake in the RG2 cells that overexpress the Lf receptor. Interestingly, an intravenous injection of the co‐delivered chemotherapeutics follows by magnetic targeting in brain tumor‐bearing mice not only achieve high accumulation at the targeted site but also more efficiently suppress cancer growth in vivo than does the delivery of either drug alone.
Mehrdimensionales De‐novo‐Moleküldesign durch adaptive Fragmentauswahl
Authors: Reutlinger Michael , Rodrigues Tiago , Schneider Petra , Schneider Gisbert
Published: March 2014

Wir präsentieren die Entwicklung und Anwendung eines computergestützten Verfahrens für das De‐novo‐Design von bioaktiven niedermolekularen Substanzen mit gewünschten Bindungsprofilen. Der Ansatz überträgt das aus der Natur inspirierte Konzept der Ameisenkolonie‐Optimierung auf die Auswahl von kombinatorischen Synthesebausteinen. Basierend auf öffentlich zugänglichen Struktur‐Aktivitäts‐Daten haben wir ein quantitatives Polypharmakologie‐Vorhersagemodell für 640 humane Wirkstofftargets entwickelt. Am Beispiel der reduktiven Aminierung zeigen wir den Entwurf von sowohl selektiven als auch Multi‐Target‐modulierenden Dopamin‐D4‐Antagonisten sowie Sigma‐1‐Rezeptor‐selektiven Liganden mit genau vorausgesagten Affinitäten. Die nanomolaren Potenzen der erzielten Treffer, ihre hohe Ligandeneffizienz und eine Erfolgsquote von 90 % zeigen, dass die computerbasierte Moleküldesignmethode für die schnelle Entwicklung fokussierter kombinatorische Substanzbibliotheken geeignet ist.
Stimuli‐Responsive Theragrippers for Chemomechanical Controlled Release
Authors: Malachowski Kate , Breger Joyce , Kwag Hye Rin , Wang Martha O. , Fisher John P. , Selaru Florin M. , Gracias David H.
Published: March 2014

We report on a therapeutic approach using thermo‐responsive multi‐fingered drug eluting devices. These therapeutic grippers referred to as theragrippers are shaped using photolithographic patterning and are composed of rigid poly(propylene fumarate) segments and stimuli‐responsive poly(N‐isopropylacrylamide‐co‐acrylic acid) hinges. They close above 32 °C allowing them to spontaneously grip onto tissue when introduced from a cold state into the body. Due to porosity in the grippers, theragrippers could also be loaded with fluorescent dyes and commercial drugs such as mesalamine and doxorubicin, which eluted from the grippers for up to seven days with first order release kinetics. In an in vitro model, theragrippers enhanced delivery of doxorubicin as compared to a control patch. We also released theragrippers into a live pig and visualized release of dye in the stomach. The design of such tissue gripping drug delivery devices offers an effective strategy for sustained release of drugs with immediate applicability in the gastrointestinal tract.
Diastereoselective Carbocyclization of 1,6‐Heptadienes Triggered by Rhodium‐Catalyzed Activation of an Olefinic CH Bond
Authors: Aïssa Christophe , Ho Kelvin Y. T. , Tetlow Daniel J. , Pin‐Nó María
Published: March 2014

The use of α,ω‐dienes as functionalization reagents for olefinic carbon–hydrogen bonds has been rarely studied. Reported herein is the rhodium(I)‐catalyzed rearrangement of prochiral 1,6‐heptadienes into [2,2,1]‐cycloheptane derivatives with concomitant creation of at least three stereogenic centers and complete diastereocontrol. Deuterium‐labeling studies and the isolation of a key intermediate are consistent with a group‐directed CH bond activation, followed by two consecutive migratory insertions, with only the latter step being diastereoselective.
Short Stereoselective Synthesis of the Phytophthora Universal Mating Hormone α1 Using Lithiation/Borylation Reactions
Authors: Pulis Alexander P. , Fackler Philipp , Aggarwal Varinder K.
Published: March 2014

The universal mating hormone α 1 of the virulent plant pathogen Phytophthora has been synthesized in 12 steps and 28 % overall yield. Key CC bond‐forming steps involved the use of two lithiation/borylation reactions to couple together enantioenriched building blocks, one of which also set up the stereochemistry of the tertiary alcohol at C11. Detailed analysis showed that the diastereomeric purity of the target molecule was >91 %, the highest obtained to date.
Investigation of fungicidal activity of 3‐piperazine‐bis(benzoxaborole) and its boronic acid analogue
Authors: Wieczorek Dorota , Lipok Jacek , Borys Krzysztof M. , Adamczyk‐Woźniak Agnieszka , Sporzyński Andrzej
Published: March 2014

3‐Piperazine‐bis(benzoxaborole) and its bis(phenylboronic acid) analogue were investigated in terms of their fungicidal activity. The study was carried out against five filamentous fungi: Aspergillus terreus, Fusarium dimerum, Fusarium solani, Penicillium ochrochloron and Aspergillus niger. 3‐Piperazine‐bis(benzoxaborole) revealed higher inhibitory activity towards the examined strains than standard antibiotic (amphotericin B), whereas bis(phenylboronic acid) proved to be inactive. The study unequivocally showed that the presence of the heterocyclic benzoxaborole system is essential for antifungal action of the examined compounds. Copyright © 2014 John Wiley & Sons, Ltd.
Collagen‐immobilized poly(ethylene terephthalate)‐g‐poly(vinyl alcohol) fibers prepared by electron‐beam co‐irradiation
Authors: Dai Guoliang , Xiao Hong , Zhu Shifeng , Shi Meiwu
Published: March 2014

Vinyl acetate was grafted onto poly(ethylene terephthalate) (PET) fibers under electron‐beam co‐irradiation. Then, the grafted products were hydrolyzed under HCl solution to obtain PET‐g‐poly(vinyl alcohol) (PVA) fibers. Afterward, to impart superior hydrophilicity and skin care, collagen was immobilized onto PET‐g‐PVA fibers with glutaraldehyde. The modified fabric was characterized in terms of moisture regain, wettability, and evaporation rate [Ev (%/h)]. The degree of alcoholysis of the grafting product was more than 90% in a 10% HCl solution at 100°C for 4 h, and its moisture regain was 1.4%. The modified PET fabric with collagen showed a shorter drip diffusion time and a higher wicking height than the unmodified PET and PET‐g‐PVA fabric before and after multiple washings. The evaporation ratio and Ev of the collagen‐immobilized PET fibers were far below those of the virgin PET fibers. The chemical structure, surface morphology, and element content of the product were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray photoelectron spectroscopy. This further certified that the collagen‐immobilized PET‐g‐PVA fiber was successfully prepared by the previous procedure. Furthermore, the PET–PVA–collagen fabric was capable of withstanding multiple washing cycles. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40597.
Investigating the structure and water permeation of membranes modified with natural and synthetic additives using tensile, porosity, and glass transition temperature studies
Authors: Vilakati Gcina Doctor , Hoek Eric M. V. , Mamba Bhekie Brilliance
Published: March 2014

This article reports the results of a study on the effect of using different additives (lignin, polyethylene glycol [PEG], and polyvinyl pyrrolidone [PVP]) to fabricate ultrafiltration polysulfone (PSf) membranes. The main focus of this study was on the difference in permeation properties brought about by the absence or presence of a fabric when fabricating the membranes. Differential scanning calorimetry was used to characterize the thermal properties and was also used to predict the other membrane properties. An Instron machine was used to evaluate the mechanical properties. The bulk porosity of lignin and PVP‐modified membranes was observed to be higher than that of the membranes modified with PEG. There was a strong negative correlation between the bulk porosity and the glass transition temperature irrespective of the additive used. Membranes cast on a fabric showed higher flux compared with membranes cast on glass. There was a strong positive correlation between the bulk porosity and the observed permeability regardless of whether the membrane was cast on a nonwoven fabric or on a glass plate. Pore‐size distribution results showed that lignin and PVP‐modified membranes had a narrow pore‐size distribution ranging between 10 and 25 nm when compared with PEG‐modified membranes with a pore‐size distribution ranging between 2.5 and 20 nm. These results indicate that thermal, bulk porosity, and mechanical properties can be used to probe the membrane structure. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40616.
Morphological evolution and properties of thermoplastic vulcanizate/organoclay nanocomposites
Authors: Li Chaoqun , Jiang Zhiwei , Tang Tao
Published: March 2014

Nanocomposites composed of organoclay and thermoplastic vulcanizates (TPVs) based on uncompatibilized or compatibilized polypropylene (PP)/ethylene–propylene–diene rubber (EPDM) blends were prepared in this study. The morphology of the nanocomposites was studied with wide‐angle X‐ray diffraction and transmission electron microscopy, which suggested that the addition of the compatibilizer played a key role in determining the morphology of the composites because of their interaction with the clay surface. Scanning electron microscopy study indicated the changes in the morphology of the rubber particles. Dynamic mechanical analysis was also applied to the analysis of these phenomena. Moreover, for nanocomposites with uncompatibilized PP/EPDM blends as the matrix, the samples showed tensile enhancement compared with neat TPV. Although the addition of the compatibilizer changed tensile properties of the composites in a rather different trend, the tensile modulus increased dramatically when the compatibilizer was added. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40618.