bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrically detected ferromagnetic resonance
Authors: Goennenwein S. T. B. , Schink S. W. , Brandlmaier A. , Boger A. , Opel M. , Gross R. , Keizer R. S. , Klapwijk T. M. , Gupta A. , Huebl H. , Bihler C. , Brandt M. S.
Published: April 2007

We study the magnetoresistance properties of thin ferromagnetic CrO2 and Fe3O4 films under microwave irradiation. Both the sheet resistance ρ and the Hall voltage VHall characteristically change when a ferromagnetic resonance (FMR) occurs in the film. The electrically detected ferromagnetic resonance (EDFMR) signals closely match the conventional FMR, measured simultaneously, in both resonance fields and line shapes. The sign and the magnitude of the resonant changes Δρ∕ρ and ΔVHall∕VHall can be consistently described in terms of a Joule heating effect. Bolometric EDFMR thus is a powerful tool for the investigation of magnetic anisotropy and magnetoresistive phenomena in ferromagnetic micro- or nanostructures.
Adaptive Q control for tapping-mode nanoscanning using a piezoactuated bimorph probe
Authors: Gunev Ihsan , Varol Aydin , Karaman Sertac , Basdogan Cagatay
Published: April 2007

A new approach, called adaptive Q control, for tapping-mode atomic force microscopy (AFM) is introduced and implemented on a homemade AFM setup utilizing a laser Doppler vibrometer and a piezoactuated bimorph probe. In standard Q control, the effective Q factor of the scanning probe is adjusted prior to the scanning depending on the application. However, there is a trade-off in setting the effective Q factor of an AFM probe. The Q factor is either increased to reduce the tapping forces or decreased to increase the maximum achievable scan speed. Realizing these two benefits simultaneously using standard Q control is not possible. In adaptive Q control, the Q factor of the probe is set to an initial value as in standard Q control, but then modified on the fly during scanning when necessary to achieve this goal. In this article, we present the basic theory behind adaptive Q control, the electronics enabling the online modification of the probe’s effective Q factor, and the results of the experiments comparing three different methods: scanning (a) without Q control, (b) with standard Q control, and (c) with adaptive Q control. The results show that the performance of adaptive Q control is superior to the other two methods.
Molecular-nanolayer-induced suppression of in-plane Cu transport at Cu-silica interfaces
Authors: Gandhi D. D. , Ganesan P. G. , Chandrasekar V. , Gan Z. , Mhaisalkar S. G. , Li H. , Ramanath G.
Published: April 2007

Recent reports have shown that molecular nanolayers (MNLs) can be used to inhibit Cu diffusion across Cu-dielectric interfaces in nanodevice wiring. Here, we demonstrate that MNLs can curtail in-plane interfacial Cu transport. Cu lines embedded in SiO2 in interdigitated comb configurations were passivated by organosilane MNLs with thiol, amino-phenyl, and amino-propyl termini. Leakage current and breakdown voltage measurements at 0–1.4MV∕cm electric fields reveal that amino-phenyl-terminated MNLs are the most effective in inhibiting in-plane leakage, likely due to Cu–N complex formation. Our results suggest that MNLs with appropriate termini could be used to tailor the stability and reliability of device wiring structures.
Optically produced cross patterning based on local dislocations inside MgO single crystals
Authors: Kanehira Shingo , Miura Kiyotaka , Fujita Koji , Hirao Kazuyuki , Si Jinhai , Shibata Naoya , Ikuhara Yuichi
Published: April 2007

Here, the authors demonstrate a unique technique to form dense dislocations locally inside a single crystal with a rocksalt-type structure using femtosecond laser irradiation for the first time, to our knowledge. Cross-shaped patterns of micrometer size, originating from densely introduced dislocations, are formed around the focal point. The authors controlled three-dimensional propagation of dislocations by adjusting the pulse energy of femtosecond laser and numerical aperture of objective lens.
Current enhanced magnetic proximity in Nd0.7Ca0.3MnO3∕YBa2Cu3O7 bilayer
Authors: Hsu Daniel , Lin J. G. , Chang C. P. , Chen C. H. , Wu W. F. , Chiang C. H. , Chan W. C.
Published: April 2007

The Nd0.7Ca0.3MnO3∕YBa2Cu3O7 (NCMO/YBCO) bilayer is fabricated with the method of pulsed laser deposition, and the current dependent proximity effects are investigated. Our experimental data show that the suppression rate of superconducting transition temperature (Tc) with respect to the applied current (>1mA) is enhanced by one order of magnitude in NCMO/YBCO compared with that in pure YBCO. The enhanced Tc suppression is attributed to pair breaking via the interactions with the spin-polarized quasiparticles and the magnetic exchange, in association with a current-induced melting of the charge-order state in NCMO.
Effect of capping layer on the spin accumulation and magnetoresistance of a current-perpendicular-to-plane spin valve
Authors: Bala Kumar S. , Tan S. G. , Jalil M. B. A.
Published: April 2007

The authors present a theoretical analysis of spin accumulation and magnetoresistance (MR) of a current-perpendicular-to-plane multilayer device with an additional nonmagnetic capping layer (NCL). They found that increased spin relaxation within the NCL may result in either an increase or a decrease of spin accumulation within the free ferromagnetic layer, depending on the fixed layer thickness. This raises the possibility of using spin relaxation in the NCL as a means of optimizing the current-induced magnetization switching effect. Additionally, the authors found that although the overall MR is decreased by the addition of the NCL, this decrease may be mitigated by strong spin relaxation within the capping layer.
rf superconducting quantum interference device metamaterials
Authors: Lazarides N. , Tsironis G. P.
Published: April 2007

A rf superconducting quantum interference device (SQUID) array in an alternating magnetic field is investigated with respect to its effective magnetic permeability, within the effective medium approximation. This system acts as an inherently nonlinear magnetic metamaterial, leading to negative magnetic response, and thus negative permeability above the resonance frequency of the individual SQUIDs. Moreover, the permeability exhibits oscillatory behavior at low field intensities, allowing its tuning by a slight change of the intensity of the applied field.
Spatial refractive index sensor using whispering gallery modes in an optically trapped microsphere
Authors: Zijlstra Peter , van der Molen Karen L. , Mosk Allard P.
Published: April 2007

The authors propose the use of an optically trapped, dye doped polystyrene microsphere for spatial probing of the refractive index at any position in a fluid. Using the dye embedded in the microsphere as an internal broadband excitation source the authors eliminated the need for a tunable excitation source. They measured the full width at half maximum and frequency spacing of the transverse electric and transverse magnetic resonances as a function of the refractive index of the immersion fluid. The authors achieved a sensitivity of 5×10−4 in refractive index, even when the exact size of the microsphere was not known.
Dynamics of low-coordinated surface atoms on gold nanocrystallites
Authors: McKenna K. P. , Sushko P. V. , Shluger A. L.
Published: April 2007

The authors highlight the importance of transient configurations of atoms on the surface of nanocrystallites, and present methodologies for their investigation. A Monte Carlo method has been developed and is used to simulate the thermodynamic equilibrium of nanometer sized Au nanocrystallites, both free and supported on a MgO(100) surface. The authors find that appreciable numbers of atoms transiently occupy adatom positions on Au(111) facets, even at room temperature. This type of dynamically appearing site is usually neglected in relation to catalysis but may have a significant activity (for CO oxidation, for example). They also observe a complex solid-solid roughening transition which involves a variety of transient local atom configurations on the surface of nanocrystallites.
Suppressed growth of unstable low-k GeOx interlayer in Ge metal-oxide-semiconductor capacitor with high-k gate dielectric by annealing in water vapor
Authors: Zou X. , Xu J. P. , Li C. X. , Lai P. T.
Published: April 2007

The effects of water vapor added in the N2 annealing of high-k HfTiON gate dielectric on Ge metal-oxide-semiconductor capacitor are investigated. Both transmission-electron microscopy and ellipsometry indicate that, as compared to dry-N2 annealing, the wet-N2 annealing can greatly suppress the growth of unstable low-k GeOx at the dielectric/Ge interface, thus resulting in smaller equivalent dielectric thickness, as well as less interface states and dielectric charges. All these are attributed to the hydrolyzable property of GeOx in water. Moreover, the wet-N2 annealed capacitor has ten times lower gate-leakage current due to its better dielectric morphology as confirmed by atomic force microscopy.
Unidirectional laser emission from π-conjugated polymer microcavities with broken symmetry
Authors: Tulek A. , Vardeny Z. V.
Published: April 2007

We report unidirectional laser emission from π-conjugated polymer microcavities with broken symmetry geometries such as spiral and microdisk containing a “line defect,” in comparison with plain microdisk cavity having isotropic emission. We found that the laser emission directionality contrast ratio is 8–10 and far field lateral divergence angle is 12°–15° for both broken symmetry geometries, with no significant increase in the laser threshold intensity. Fourier transform analysis of the laser emission spectra shows that unlike microdisks with line defect, the variation of light trajectories in the spiral microcavities leads to less defined laser modes.
Computational study on the negative electron affinities of NO2−∙(H2O)n clusters (n=–30)
Authors: Ejsing Anne Marie , Brøndsted Nielsen Steen
Published: April 2007

Here we report negative electron affinities of NO2−∙(H2O)n clusters (n=0–30) obtained from density functional theory calculations and a simple correction to Koopmans' theorem. The method relies on the calculation of the detachment energy of the monoanion and its highest occupied molecular orbital and lowest unoccupied molecular orbital energies, and explicit calculations on the dianion itself are avoided. A good agreement with resonances in the cross section for neutral production in electron scattering experiments is found for n=0, 1, and 2. We find several isomeric structures of NO2−∙(H2O)2 of similar energy that elucidate the interplay between water-water and ion-water interactions. The topology is predicted to influence the electron affinity by 0.5 and 0.4eV for NO2−∙(H2O) and NO2−∙(H2O)2, respectively. The electron affinity of larger clusters is shown to follow a (n+δ)−1∕3 dependence, where δ=3 represents the number of water molecules that in volume, could replace NO2−.
Epitaxial growth and formation of interfacial misfit array for tensile GaAs on GaSb
Authors: Huang S. H. , Balakrishnan G. , Mehta M. , Khoshakhlagh A. , Dawson L. R. , Huffaker D. L. , Li P.
Published: April 2007

The authors report the formation of an interfacial misfit (IMF) array in the growth of relaxed GaAs bulk layers on a (001) GaSb surface. Under specific conditions, the high quality IMF array has a period of 5.6nm and can accommodate the 7.78% tensile GaAs∕GaSb lattice mismatch. The misfit site is identified as a 90° edge dislocation using Burger’s circuit theory and confirmed by high-resolution cross-section transmission electron microscopy (TEM) images. The resulting GaAs bulk material is both strain-free and highly crystalline. Plan-view TEM images show threading dislocation density of ∼3×106∕cm2. This material demonstration will enable novel device structures including an embedded GaSb active region in GaAs device matrix.
Organic-based tristimuli colorimeter
Authors: Antognazza M. R. , Scherf U. , Monti P. , Lanzani G.
Published: April 2007

The authors realize three photodiodes based on organic materials, which have photoresponse curves matched to the colorimetric functions of the standard observer. Such a system of detectors is used for realizing a three-stimuli colorimeter. They report the result of measurements in different spectral areas and suggest possible application of the device in color science and artificial vision.
Reflective second harmonic generation from ZnO thin films: A study on the Zn–O bonding
Authors: Lo Kuang Yao , Huang Yi Jen , Huang Jung Y. , Feng Zhe Chuan , Fenwick William E. , Pan Ming , Ferguson Ian T.
Published: April 2007

The structures of the Zn–O bonding in ZnO (0002) thin films prepared by metal organic chemical vapor deposition have been studied by reflective second harmonic generation (RSHG). The polar Zn–O bond on the top layer is not canceled out and presents 3mm symmetrical structures on the well-grown ZnO (0002) surface. The average polar strength of the Zn–O bond is correlated with the quality of the ZnO (0002) thin film. The mirror symmetry is caused by the nonvanished polar of twin boundary due to the mismatch between the ZnO film and sapphire substrate and analyzed using s-polarized RSHG with s-polarized fundamental light irradiation. These results demonstrate that the Zn–O heteropolar bonds on the smooth ZnO surface contribute to the SHG intensity.
Elastic properties of yttrium-doped BaCeO3 perovskite
Authors: Zhang Jianzhong , Zhao Yusheng , Xu Hongwu , Li Baosheng , Weidner Donald J. , Navrotsky Alexandra
Published: April 2007

Based on ambient ultrasonic measurements and x-ray diffraction under hydrostatic compression, the authors report here a comparative study of elasticity on oxygen-deficient perovskite, BaCe1−xYxO3−0.5x, with x=0.00 and 0.15. The results show that the presence of 2.5% oxygen vacancy has no measurable effect on the elastic bulk modulus. The shear modulus, however, decreases by approximately 5% in BaCe0.85Y0.15O2.925 perovskite. The differences between Y3+-doped cerate and Al3+-doped silicate suggest that the effect of oxygen vacancy on the elastic properties could be system dependent and may also be sensitive to distribution of oxygen vacancies within structures of the parent compounds.
Work function of small radius carbon nanotubes and their bundles
Authors: Su W. S. , Leung T. C. , Li Bin , Chan C. T.
Published: April 2007

Carbon nanotube work functions can deviate from that of graphene due to geometric and structural factors. The authors have systematically investigated the work functions of various forms of small radius carbon nanotubes and their derivatives by density functional calculations. They considered and compared the work functions of tubes and tube bundles in order to understand the effects of chirality, tube length, and capping condition. Systematic trends are unraveled and discussed.
Diagnostic system to measure spatial and temporal profiles of shock front using compact two-stage light-gas gun and line reflection method
Authors: Yokoo Manabu , Kawai Nobuaki , Hironaka Yoichiro , Nakamura Kazutaka G. , Kondo Ken-ichi
Published: April 2007

A diagnostic system has been developed to obtain spatial and temporal profiles of shock front. A two-stage light-gas gun is used to accelerate impactors in velocity range with 4–9 km/s. The system consists of the Faraday-type electromagnetic sensors to measure impactor velocity, optical system with high-speed streak camera to measure shock-wave velocities, and the delay trigger system with self-adjustable pre-event pulse generator. We describe the specifications and performance of this system and data-analysis technique on the tilt and distortion of the shock front. Finally, we obtained the Hugoniot data of copper for system demonstration.
200
ns
pulse high-voltage supply for terahertz field emission
Authors: Welsh Gregor H. , Turton David A. , Jones David R. , Jaroszynski Dino A. , Wynne Klaas
Published: April 2007

We present a method of generating 200ns high-voltage (up to 40kV) pulses operating at repetition rates of up to 100kHz, which may be synchronized with laser pulses. These supplies are simple to make and were developed for ultrafast terahertz pulse generation from GaAs photoconductive antennas using a high-repetition-rate regeneratively amplified laser. We also show an improvement in signal-to-noise ratio over a continuous dc bias field and application of the supply to terahertz pulse generation.
Spin-dependent transport properties in GaMnAs-based spin hot-carrier transistors
Authors: Mizuno Yosuke , Ohya Shinobu , Hai Pham Nam , Tanaka Masaaki
Published: April 2007

The authors have investigated the spin-dependent transport properties of GaMnAs-based “three-terminal” semiconductor spin hot-carrier transistor (SSHCT) structures. The emitter-base bias voltage VEB dependence of the collector current IC, emitter current IE, and base current IB shows that the current transfer ratio α (=IC∕IE) and the current gain β (=IC∕IB) are 0.8–0.95 and 1–10, respectively, which means that GaMnAs-based SSHCTs have current amplification capability. In addition, the authors observed an oscillatory behavior of the tunneling magnetoresistance ratio with the increasing bias, which can be explained by the resonant tunneling effect in the GaMnAs quantum well.
Improved GaN materials and devices through confined epitaxy
Authors: Eddy C. R. , Holm R. T. , Henry R. L. , Twigg M. E. , Bassim N. D. , Shirey L. M. , Glembocki O. J. , Culbertson J. C. , Perkins F. K. , Peckerar M. C. , Ngu Y. , Yan F.
Published: April 2007

An approach to reduce vertical threading dislocations in the active regions of III-nitride devices is described. The approach involves confined homo- or heteroepitaxy of GaN materials using sputtered oxide masks to delineate growth regions and conventional metal-organic chemical vapor deposition. The resulting confined epitaxial material is terminated with equilibrium crystal facets, which form hexagonal mesas, and contains a reduced dislocation density and reduced strain compared to the underlying template layer for homoepitaxial growth. Characterization of pn junction diodes grown with this approach reveals significantly reduced leakage currents in as-grown, unpassivated structures (as low as 1×10−7Acm−2).
Precipitation of nanocrystals in glasses by electron irradiation: An alternative path to form glass ceramics?
Authors: Jiang N. , Wu B. , Qiu J. , Spence J. C. H.
Published: April 2007

This letter demonstrates an alternative method to form gallium silicate glass ceramics using high-energy electron irradiation. Compared with glass ceramics obtained from the conventional thermal treatment method, the distribution and crystal sizes of the precipitated Ga2O3 nanoparticles are the same. An advantage of this method is that the spatial distribution of the precipitated nanoparticles can be easily controlled. However, optically active dopants Ni2+ ions do not participate in the precipitation during electron irradiation.
Quench-disorder-controlled magnetoresistance in Sm0.55Sr0.45MnO3
Authors: Egilmez M. , Chow K. H. , Jung J. , Salman Z.
Published: April 2007

The authors studied the low-field magnetoresistance of Sm1−xSrxMnO3 (x=0.45) which was sintered at different elevated temperatures followed by fast cooling (thermal quenching). Near the metal insulator transition the magnetoresistance is dramatically enhanced while the magnitude and width of the resistive peak are significantly reduced by increasing the sintering/quenching temperature, approaching the values observed in a single crystal of the same composition. They attribute these effects to an increase of the grain size in the system.
Alignment of liquid crystals by topographically patterned polymer films prepared by nanoimprint lithography
Authors: Yi Youngwoo , Nakata Michi , Martin Alexander R. , Clark Noel A.
Published: April 2007

Nanoimprint lithographically (NIL) prepared polymer film replicas of micrometer scale topographic master patterns are used as liquid crystal alignment surfaces. Depolarized transmission light microscopy study of nematic liquid crystal cells made using the replicas as one window shows that the NIL generated linear line patterns and two-dimensional square grid patterns align the liquid crystal in planar mono- and bistable states.
Scanning electron microscopy of thinned specimens: From multilayers to biological samples
Authors: Morandi V. , Merli P. G. , Quaglino D.
Published: April 2007

The rules governing image formation of thin specimens in scanning and scanning transmission electron microscopy at low energy, deduced from the observation of semiconductor multilayers, were validated on specimens defined by a much more complex structure as the biological ones. It is shown that for a suitable specimen thickness it is possible to have, at the same time, backscattered electron images and scanning transmission electron images with a comparable resolution. Moreover, the nonconductive biological samples can be observed without charging effects if they are thin enough to ensure that a significant fraction of the electron beam crosses the specimen.
Low temperature InP∕Si wafer bonding using boride treated surface
Authors: Huang Hui , Ren Xiaomin , Wang Wenjuan , Song Hailan , Wang Qi , Cai Shiwei , Huang Yongqing
Published: April 2007

An approach for InP∕Si wafer bonding based on boride-solution treatment was presented. The bonding energy is higher than the InP fracture energy by annealing at 280°C. An In0.53Ga0.47As∕InP multiple-quantum-well (MQW) structure grown on InP was transferred onto Si substrate via the bonding process. X-ray diffraction and photoluminescence reveal that crystal quality of the bonded MQW was preserved. A thin B2O3–POx–SiO2 oxide layer of about 28nm thick at the bonding interface was detected. X-ray photoelectron spectroscopy and Raman analyses indicate that the formation of oxygen bridging bonds by boride treatment is responsible for the strong fusion obtained at such low temperature.
Enhancing the photomixing efficiency of optoelectronic devices in the terahertz regime
Authors: Pilla Subrahmanyam
Published: April 2007

A method to enhance the photomixing efficiency by reducing the transit time of majority of carriers in photomixers and photodetectors to <1ps is proposed. Enhanced optical fields associated with surface plasmon polaritons coupled with velocity overshoot phenomenon results in net decrease of transit time of carriers. As an example, model calculations demonstrating >280× (or ∼2800 and 31.8μW at 1 and 5THz, respectively) improvement in terahertz power generation efficiency of a photomixer based on low temperature grown GaAs are presented.
Spectroscopic characterization of carbon chains in nanostructured tetrahedral carbon films synthesized by femtosecond pulsed laser deposition
Authors: Hu A. , Lu Q.-B. , Duley W. W. , Rybachuk M.
Published: April 2007

A comparative study of carbon bonding states and Raman spectra is reported for amorphous diamondlike carbon films deposited using 120fs and 30ns pulsed laser ablation of graphite. The presence of sp1 chains in femtosecond carbon films is confirmed by the appearance of a broad excitation band at 2000–2200cm−1 in UV-Raman spectra. Analysis of Raman spectra indicates that the concentrations of sp1-, sp2-, and sp3-bonded carbon are ≈6%, ≈43%, and ≈51%, respectively, in carbon films prepared by femtosecond laser ablation. Using surface enhanced Raman spectroscopy, specific vibrational frequencies associated with polycumulene, polyyne, and trans-polyacetylene chains have been identified. The present study provides further insight into the composition and structure of tetrahedral carbon films containing both sp2 clusters and sp1 chains.
Spatial coherence of a periodic medium as a means for testing randomness
Authors: Giller Christophe , Doiron Serge , Beaudoin Normand , Haché Alain
Published: April 2007

It is shown that the physical properties of a periodic medium are sensitive not only to disorder but also to whether disorder is random or not. Based on this property, the authors propose and demonstrate a method to analyze the randomness of data, to detect information content, and to recognize patterns. When data are encoded by means of defects on a periodic lattice, the transmission at a single frequency reveals possible deviations from true randomness, allowing for information content to be measured. This nonlogical (noncomputational) method for data analysis shows potential for signal analysis, pattern recognition, and cryptography.
Size dependence of tetrahedral bond lengths in CdSe nanocrystals
Authors: Wu Pin-Jiun , Stetsko Yuri P. , Tsuei Ku-Ding , Dronyak Roman , Liang Keng S.
Published: April 2007

The structural characteristics of organically passivated CdSe nanocrystals (NCs) were investigated with x-ray diffraction and extended x-ray absorption fine structure. As the NC size decreases, the axial bond length R(1) for an atomic tetrahedron extends but the equatorial bond length R(2) contracts, with a similar tendency of distortion for the lattice parameters of the wurtzite structure. The authors suggest that the observed hexagonal distortion is attributed to the surface stress of the NCs related to the organic passivation effect and the relaxation of atomic positions at the stacking fault interface.
Evidence of band structure modification of LiMn2O4 upon lithium deintercalation by photoacoustic spectroscopy
Authors: Lee S. Thomas , Raveendranath K. , Tomy M. Rajive , Paulraj M. , Jayalekshmi S. , Ravi J.
Published: April 2007

Optical absorption spectra of cubic spinel LiMn2O4 and its delithiated form λ-MnO2 are determined using photoacoustic spectroscopy. Eight absorption peaks, in the wavelength range of 375–800nm, associated with the O 2p–Mn t2g, O 2p–Mn eg, and Mn t2g–Mn eg band transitions are identified for LiMn2O4 and λ-MnO2. Upon deintercalation of LiMn2O4, the peaks at the high energy side of the absorption spectrum (375–565nm) are blueshifted, whereas those at the low energy side (570–800nm) are redshifted. The observed effects are explained on the basis of nonrigid band model, suggesting a change in oxygen ionicity during lithium deintercalation.
Low Vπ modulators containing InGaAsP∕InP microdisk phase modulators
Authors: Stapleton Andrew , Farrell Stephen , Peng Zhen , Choi Seung-June , Christen Louis , O’Brien John , Dapkus P. Daniel , Willner Alan
Published: April 2007

The authors have demonstrated a low switching voltage modulator comprised of a 12μm radius indium phosphide (InP)-based optical microdisk phase modulator in an external Mach-Zehnder interferometer. The chip-scale phase modulator operated with a measured Vπ of 0.6mV.
Research note: Deposition patterns of cellulose microfibrils in flange wall ingrowths of transfer cells indicate clear parallels with those of secondary wall thickenings
Authors: Talbot Mark J. , Wasteneys Geoffrey , McCurdy David W. , Offler Christina E.
Published: April 2007

The arrangement of cellulose microfibrils and cortical microtubules in transfer cells depositing flange wall ingrowths have been determined with field emission scanning electron microscopy and immunofluorescence confocal microscopy. In xylem transfer cells of wheat (Triticum aestivum) stem nodes and transfer cells of corn (Zea mays) endosperm tissue, cellulose microfibrils were aligned in parallel bundles to form the linear wall ingrowths characteristic of flange ingrowth morphology. In both cell types, linear bundles of cellulose microfibrils were deposited over an underlying wall composed of randomly arranged microfibrils. Acid extraction of wheat xylem transfer cells established that flange ingrowths were composed of crystalline cellulose. Immunofluorescence labelling of microtubules in wheat xylem transfer cells showed that bundles of microtubules were positioned directly below and parallel with developing flange ingrowths, whereas more mature ingrowths were flanked by bundles of microtubules. These results show that the parallel organisation of cellulose microfibrils in flange wall ingrowths is similar to those in secondary wall thickenings in xylem elements, and that deposition of these structures in transfer cells is also likely to involve bundling of parallel arrays of microtubules. Our observations are discussed in terms of the possible role of microtubules in building flange-type wall ingrowths and the consequences in terms of predicted mechanisms required to build the fundamentally different reticulate-type wall ingrowths.
Biocompatible coatings for CMUTs in a harsh, aqueous environment
Authors: Zhuang X , Nikoozadeh A , Beasley M A , Yaralioglu G G , Khuri-Yakub B T , Pruitt B L
Published: April 2007

The results of coating capacitive micromachined ultrasonic transducer (CMUT) arrays with two different biocompatible materials, parylene-c and polydimethylsiloxane (PDMS), are reported. These materials were characterized for use with CMUTs to enable direct contact transcutaneous andin vivoimaging. A passivation coating is required to provide electrical isolation to the active areas of the device and to protect it from a corrosive environment. It must also provide good mechanical characteristics to void imaging artifacts. The coated devices were compared side by side with uncoated devices for testing in air. The resonant frequency, collapse voltage and crosstalk were sampled. Parylene coated CMUTs were also tested underwater using pulse excitation. The parylene coating provided electrical insulation to the aqueous solution for 14 days. Both coatings showed a decrease in device resonant frequency and an increase in collapse voltage, as expected from the proposed theory.
The Life of Antony: Text and Context
Authors: Harmless William, S.J.
Published: April 2007

Athanasius’ Life of Antony (Vita Antonii) became a classic almost overnight and helped create a new genre of Christian literature: the life of a saint. Closer in spirit to Beowulf or Raiders of the Lost Ark, the Life of Antony is a tale of high adventure, of pitched battles against nefarious supernatural forces, set within an exotic landscape. This chapter surveys the basic plot, including Antony’s call and his much-illustrated temptations, his flight from the world (anachoresis), his healings, visions, and prophecies. It also examines the work’s literary context, illustrating how Athanasius both draws on and plays against traditions of ancient biography.
Pachomius
Authors: Harmless William, S.J.
Published: April 2007

Pachomius (c.292–346) is often (and somewhat inaccurately) singled out as the founder of cenobitic monasticism, that is, of monks living in organized communities. He established in Upper Egypt a remarkable confederation of monasteries—known as the Koinonia (“Fellowship”)—that housed hundreds, perhaps thousands of monks. He also composed the first known monastic rule. This chapter examines the early biographies of Pachomius—especially the First Greek Life and the Bohairic Life. It also reconstructs daily life within the Koinonia and its development under Pachomius's successors, Theodore and Horsiesius.
The Apophthegmata Patrum: Portraits
Authors: Harmless William, S.J.
Published: April 2007

The Apophthegmata Patrum has come down to us in two basic forms: the Alphabetical Collection and the Systematic Collection. The Alphabetical Collection gathers some 1,000 sayings and brief narratives under the names of 130 prominent monks and arranges these according to the Greek alphabet. This chapter focuses on the Alphabetical Collection, whose poignant anecdotes—like a set of snapshots in a photo album—offer striking portraits of leading desert fathers. This chapter explores the Apophthegmata’s portraiture of four figures from Scetis: Abba Macarius the Egyptian, Abba John the Little, Abba Moses the Ethiopian, and Abba Poemen.
The Apophthegmata Patrum: Themes
Authors: Harmless William, S.J.
Published: April 2007

The Apophthegmata Patrum has come down to us in two basic forms: the Alphabetical Collection and the Systematic Collection. The Systematic Collection contains many of the same sayings and stories as the Alphabetical but gathers them under twenty-one different headings or themes, such as “discernment” and “unceasing prayer.” Two Roman clerics, Pelagius and John, translated this from Greek into Latin, and so it passed to the Latin West under the title Verba Seniorum (Sayings of the Old Men) and as such would powerfully influence the spirituality of medieval monasticism. This chapter focuses on seven key themes from the Apophthegmata: interior stillness (hesychia), thoughts (logismoi), sexuality, anger, compunction (penthos), visions, and the use of scripture.
Monastic Origins: Perspectives, Discoveries, and Disputed Questions
Authors: Harmless William, S.J.
Published: April 2007

This final chapter explores new perspectives on the origins of Christian monasticism. It includes a study of newly discovered papyri that highlight the place of edge-of-the-village ascetics (apotaktikoi) and papyri that testify to monastic organizations among schismatics, such as the Melitians. It also surveys recent research on monasticism outside of Egypt, especially in Syria, Cappadocia, and Palestine. It then probes ascetic movements outside Christianity, especially the Manichees, and assesses claims that these influenced Christian monasticism. Finally it examines both underappreciated trends, especially women’s asceticism, and overlooked figures, especially Shenoute of Atripe.
Technology and Competitiveness
Authors: Miozzo Marcela , Walsh Vivien
Published: April 2007

This chapter developes on the relation between innovation and economic development, drawing on the work of Schumpeter and Marx. The chapter is organized as follows. The first section discusses the limitations of mainstream economics in dealing with innovation. The second section presents an alternative view of the relation between innovation and economic development. The third section discusses long-term fluctuations in economic development. The fourth section examines the limitations of the most popular indices of competitiveness. The final section explores the concept of competitiveness.
Organizations and Technology in Proprietary and Managerial Capitalism
Authors: Miozzo Marcela , Walsh Vivien
Published: April 2007

This chapter focuses on 19th century institutions that enabled Britain to become a leading industrial economy (proprietary capitalism), but which impeded the adoption of technological and organizational innovations in the 20th century. It also describes consolidations of new institutions in the US and Germany (managerial capitalism) in the early 20th century, which led to important leaps in productivity and competitiveness. These institutions are part of the rise of the modern corporation and the managerial coordination of mass distribution and production.
National Innovation Systems
Authors: Miozzo Marcela , Walsh Vivien
Published: April 2007

This chapter examines the concept of national innovation systems (NIS). It analyses why NIS is important. It discusses some of the institutions which can be considered to form the NIS: business firms, educational institutions, public sector research establishments, public policy, financial institutions, legal institutions, trade unions and political organizations, and ethos, culture and attitude towards entrepreneurship, and risk taking.
Technology, International Investment, and Trade
Authors: Miozzo Marcela , Walsh Vivien
Published: April 2007

This chapter examines the ways in which trade and the operation of multinationals have influenced the operation of national production systems, and how this has changed between the period of ‘classic multinationalization’ and the period called ‘globalization’. It discusses the relevance of different theories of international business and trade (product cycle, new trade theory, eclectic theory, global commodity chains, geography and knowledge creation, and globalization of innovation) for understanding the relation between technology and changing international division of labour. A background of the changes in international trade negotiations (World Trade Organization) is discussed and a framework for policy is provided, which has important implications for innovation.
Post-hurricane Analysis of Citrus Canker II: Predictive Model Estimation of Disease Spread and Area Potentially Impacted by Various Eradication Protocols Following Catastrophic Weather Events
Authors: Gottwald Tim R. , Irey Michael
Published: April 2007

The impact of 2005 Hurricane Wilma on the dissemination of Xanthomonas axonopodis pv. citri (Xac), the cause of Asiatic citrus canker (ACC), and subsequent disease development was examined and predictions for the areas into which Xac was likely to have spread from known sources of infection were developed. In addition, the effect of the current 579-m (1900-ft) ACC eradication protocol, resulting in removal of all “exposed trees” with a 579-m radius of a known Xac-infected tree, was calculated via GIS analysis and expressed as the predicted “impacted area.” The GIS calculations were based on the extension of the previous published wind-rain index vector (WRIV) model. The model extension consisted of the incorporation of an estimate of distance of spread due to various combinations of wind and rain from data collected during the 2004 hurricane season. An inverse power law dissemination function was used to describe regional dispersal from a point focus of Xac infection. Alternative eradication protocol (distances) to the 579-m protocol were evaluated in association with the GIS analyses and used to examine the effect of eradication distance on predicted “impacted area.” The results of these analyses were used by state and federal regulatory agencies and commercial citrus producer groups to evaluate the feasibility of continued ACC eradication.

Accepted for publication 23 January 2007. Published 5 April 2007.
European Surgeons Were the First to Perform Neck Dissection
Authors: Ferlito Alfio , Johnson Jonas T. , Rinaldo Alessandra , Pratt Loring W. , Fagan Johannes J. , Weir Neil , Suárez Carlos , Folz Benedikt J. , Bień Stanislaw , Towpik Edward , Leemans C Renè , Bradley Patrick J. , Kowalski Luiz P. , Herranz Jesús , Gavilán Javier , Olofsson Jan
Published: April 2007

The history of the surgical treatment of cervical lymph node metastases began in the 19th century, and, unfortunately, the initial attempts at surgical treatment of neck metastases were disastrous. Although some European surgeons reported few cases of radical en bloc dissection, the first successful surgical procedure was performed and described in detail by Franciszek Jawdyński, a Polish surgeon, in 1888. George Washington Crile popularized and illustrated radical en bloc neck dissection in the early 20th century.
Lateralized Differences in Olfactory Function
Authors: Gudziol Volker , Hummel Cornelia , Negoias Simona , Ishimaru Tadashi , Hummel Thomas
Published: April 2007

Background: Birhinal testing of odor identification will not allow the detection of unilateral olfactory loss. The aim of the presented study was to evaluate side differences of odor identification in large groups of healthy subjects and in patients with nasal symptoms.

Participants and Method: Self‐assessment of olfactory function and evaluation of olfactory function by means of a validated test were performed in 479 healthy subjects, in 765 patients with chronic rhinosinusitis (CRS), and in 53 patients with a tumor. A 12‐item odor identification test (“Sniffin' Sticks”) was used to evaluate olfactory function separately for each nostril.

Results: Fifteen percent of the healthy subjects demonstrated side differences in the identification of at least 3 out of 12 odors. Healthy elderly subjects showed larger side differences in identification of odor than younger ones; a general difference between odor identification with the right or left nostril was not found. Both CRS patients and patients with a tumor had larger side differences than healthy subjects. Only 20% of the patients with a tumor complained about impaired olfactory sensitivity, but more than 75% of them showed deficits in olfactory tests.

Conclusion: Side differences of odor identification of 25% or greater should give reason for further investigation. Future studies are needed to investigate whether side differences in healthy subjects are a predicator of a higher risk for general olfactory loss.
Transoral Robot‐Assisted CO2 Laser Supraglottic Laryngectomy: Experimental and Clinical Data
Authors: Solares C Arturo , Strome Marshall
Published: April 2007

Background: Transoral CO2 laser surgery for selected supraglottic tumors results in improved postoperative function and decreased morbidity, with comparable survival to open surgery. Recently, robot‐assisted techniques have been reported for the management of supraglottic lesions. There are no reports in the English literature of robotic technology coupled with CO2 laser technology. Our objective was to report the use of such technology.

Study Design: Experimental resection of the supraglottis in a cadaver and a dog model using a commercially available surgical robot coupled with CO2 laser technology. Initial human experience with such technology is reported.

Methods: With use of a hollow core fiber that allows the transmission of CO2 laser energy linked to the daVinci Surgical Robot, a supraglottic laryngectomy was performed in an edentulous female cadaver. The FK Laryngo‐Pharyngoscope was used for exposure. In a second experiment, a supraglottic partial laryngectomy was performed in an 80 pound dog. On the basis of our experimental experience, a CO2 laser robotic‐assisted supraglottic laryngectomy was attempted in three patients.

Results: Removal of the supraglottic larynx in both a cadaver and canine experimental models was believed to be satisfactory using this technology. Bleeding was easily controlled in the live canine model. A 74‐year‐old woman with a large supraglottic mass for which she had been offered a total laryngectomy was resected successfully with this technology. The FK Laryngo‐Pharyngoscope provided excellent exposure. The patient was able to swallow without difficulty on postoperative day 5. Follow‐up endoscopic examination at 1 month showed no evidence of residual laryngeal tumor. Robot‐assisted procedures were attempted in two additional patients, but adequate exposure could not be achieved, and more traditional techniques were performed.

Conclusions: The use of the daVinci Surgical robot coupled with CO2 laser technology is feasible, as demonstrated by our experimental and clinical data. Although further development of the robotic technology is required at present, the use of robotics coupled with CO2 laser technology may have important implications in the management of supraglottic laryngeal cancer in the future.
A New De Novo Missense Mutation in Connexin 26 in a Sporadic Case of Nonsyndromic Deafness
Authors: Primignani Paola , Trotta Luca , Castorina Pierangela , Lalatta Faustina , Cuda Domenico , Murri Alessandra , Ambrosetti Umberto , Cesarani Antonio , Curcio Cristina , Coviello Domenico , Travi Maurizio
Published: April 2007

Objectives: Mutations in the GJB2 gene, encoding Connexin 26, can cause nonsyndromic recessive deafness or dominant hearing loss (HL) with or without keratoderma. The objective was to perform a molecular evaluation to establish the inherited pattern of deafness in the sporadic cases afferent to our center.

Methods: The subject was a 2‐year‐old Italian girl with nonsyndromic early onset HL. We performed DNA sequencing of the GJB2 gene and deletion analysis of the GJB6 gene in all family members.

Results: Direct sequencing of the gene showed a heterozygous C→G transition at nucleotide 172 resulting in a proline to alanine amino acid substitution at codon 58 (P58A). The analyses indicate that the P58A mutation appeared de novo in the proband with a possible dominant effect.

Conclusions: This mutation occurs in the first extracellular domain (EC1), which seems to be very important for connexon‐connexon interaction and for the control of voltage gating of the channel. The de novo occurrence of an EC1 mutation in a sporadic case of deafness is consistent with the assumption that P58A can cause dominant HL.
Laryngeal Electromyography in Adults With Parkinson's Disease and Voice Complaints
Authors: Zarzur Ana Paula , Duprat André C. , Shinzato Gilson , Eckley Claudia A.
Published: April 2007

Objective: To study the laryngeal electromyography (LEMG) pattern in patients with Parkinson's disease (PD) and vocal complaints.

Study Design and Setting: Twenty‐six adults with PD and vocal complaints and 26 controls with presbyphonia underwent videolaryngoscopy (VL) and LEMG.

Results: No tremor was found on LEMG of the cricothyroid and thyroarytenoid muscles, even in cases with clinical and VL tremor. LEMG hypertonicity during voice rest was the typical feature observed in 73% of the patients with PD versus 23% of the controls. This difference was statistically significant. The severity of the disease, diagnosis, and the time of treatment did not correlate with LEMG findings.

Conclusion: This is the first study reporting the use of LEMG in a large series of patients with PD and vocal complaints. Patients with PD presented spontaneous intrinsic laryngeal muscle activity during voice rest.

Significance: The typical patterns in LEMG suggest this to be a valuable diagnostic tool in PD.
A Possible Role of CD4+CD25+ T Cells as Well as Transcription Factor Foxp3 in the Dysregulation of Allergic Rhinitis
Authors: Xu Geng , Mou Zhonglin , Jiang Hongyan , Cheng Lei , Shi Jianbo , Xu Rui , Oh Yun , Li Huabin
Published: April 2007

Background: Allergic rhinitis (AR) is a Th2 predominant disease, and its pathogenic mechanism is still poorly understood. CD4+CD25+ T cells account for approximately 5% to 10% peripheral CD4+ T cells and has been shown to regulate the activation of effector T cells in the periphery. The activity of CD4+CD25+ T cells is associated with the transcription factor Foxp3. The present study aimed to evaluate the possible role of CD4+CD25+ T cells as well as Foxp3 in the pathogenesis of AR.

Methods: Nasal tissues and peripheral blood mononuclear cells (PBMCs) were obtained from 17 patients with AR and 11 control subjects. Foxp3 was detected in nasal tissues by immunohistochemistry and real‐time reverse transcription‐polymerase chain reaction (RT‐PCR). CD4+CD25+ T cells and Foxp3 were evaluated in PBMCs by using flow cytometry. Concentrations of interleukin‐2 (IL‐2) and interferon‐γ (IFN‐γ) were measured by enzyme‐linked immunosorbent assay (ELISA) in cultured PBMCs in the presence or absence of stimulation with phorbol ester (PMA) and Ionomycin.

Results: The numbers of Foxp3+ cells was 129.5 ± 35.6 and 44.2 ± 20.5 cells/mm2 in nasal mucosa of two groups (P < .05). There were less Foxp3+ lymphocytes and decreased Foxp3 mRNA in AR compared with the control (P < .05). The frequencies of the CD4+CD25+ population in PBMCs of two groups were 1.99 ± 0.95% and 3.55 ± 1.27% (P < .05). There was significant difference in the frequencies of the Foxp3+CD4+ CD25+ population (1.81 ± 0.77 vs 3.37 ± 1.04, P < .05) and mean fluorescence intensity (MFI) of Foxp3 (5.93 ± 2.64 vs 11.72 ± 4.29, P < .05) in PBMCs of two groups. After stimulation, the concentrations of IL‐2 and IFN‐γ were 182.72 ± 85.11 pg/mL and 348.94 ± 151.88 pg/mL in PBMCs with AR, while those were 90.6 ± 61.5 pg/mL and 155.64 ± 68.33 pg/mL in controls (P < .05).

Conclusion: Our results indicate that CD4+ CD25+ regulatory T cells as well as Foxp3 may play a crucial role in immunological imbalance of AR. These findings suggest that increasing Foxp3 and CD4+CD25+ T cells have the potential to be new therapeutic targets for the treatment of AR.