bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of adenomatous polyposis coli (APC) tumor supressor gene in human colon cancer cell lines on cell cycle arrest by apigenin
Authors: Chung C.S. , Jiang Y. , Cheng D. , Birt D.F. 
Published: July 2007

AbstractThis research assessed the importance of the adenomatous polyposis coli (APC) tumor suppressor mutation in the ability of apigenin to induce cell cycle arrest using HT29–APC cells, which contain inducible wild‐type APC under the metallothionein promoter. HT29–GAL cells, containing β‐galactosidase (GAL), were included as control. Treatment with apigenin (0, 20, 40, 60, and 80 µM) for 48 h resulted in reduction in the cell number (P < 0.05) concurrent with flow cytometry results showing a dose‐dependent accumulation of cells in the G2/M phase in both HT29–APC and HT29–GAL cells without ZnCl2 treatment. Flow cytometric analysis showed an increase (P < 0.05) in the percentage of cells in G2/M when HT29–APC cells were treated with 80 µM apigenin for 120 h. This increase was not present in HT29–APC cells when treated with both 80 µM apigenin and 100 µM ZnCl2 for 120 h. Western blot analysis verified the induction of APC protein expression in ZnCl2‐treated HT29–APC cells but not in ZnCl2‐treated HT29–GAL cells. Apigenin plus ZnCl2 treatment increased the expression of APC protein in HT29–APC cells by 50 fold above expression observed with ZnCl2 alone. Upon induction of the APC gene with ZnCl2 in HT29–APC cells, the percentage of apoptotic cells increased significantly (P < 0.05) after 120‐h treatment. Additionally, apigenin treatment (80 µM) further increased the percentage of apopototic HT29–APC following ZnCl2 treatment to induce wild‐type APC expression. These results suggest that APC dysfunction may be critical for apigenin to induce cell cycle arrest in human colon cancer cell lines and furthermore, apigenin enhances APC expression and apoptosis in cells with wild‐type APC. © 2007 Wiley‐Liss, Inc.
Inactivation of p27Kip1 promotes chemical mouse liver tumorigenesis in the resistant strain C57BL/6J
Authors: Sun Daqian , Ren Hao , Oertel Michael , Sellers Rani S. , Shafritz David A. , Zhu Liang 
Published: July 2007

AbstractThe biochemical function of p27Kip1 as an inhibitor of cyclin‐dependent kinases is well‐established, but the role of p27 as a tumor suppressor depends on specific cellular contexts. Previous studies using p27 knockout mice on mixed C57BL/6J × 129/Sv strain background did not find a tumor suppressor role of p27 in the liver. An important feature of mouse liver tumorigenesis is strain‐dependent tumor susceptibility. Here, we determined the role of p27 in liver tumorigenesis in C57BL/6J mice, a liver tumor resistant strain, in response to a diethylnitrosamine (DEN) and phenolbarbital (PB) two‐stage carcinogenesis protocol. At 6 mo of age, while livers of DEN–PB treated p27+/+ and p27−/− C57BL/6J mice appeared morphologically normal, p27−/− livers, but not p27+/+ livers, contained readily detectable glucose‐6‐phosphatase (G6Pase)‐deficient foci. At the 9‐mo time point, p27−/− mice developed significantly enhanced liver tumor phenotypes than p27+/+ mice as demonstrated by increased numbers and sizes of liver surface nodules, increased liver‐to‐body weight ratios, and increased numbers of G6Pase‐deficient nodules and histologically diagnosed foci and adenomas in liver sections. Hepatic lesions in p27−/− livers contained more proliferating hepatocytes than lesions in p27+/+ livers, while the numbers of apoptotic cells appeared similar in lesions of both genotypes. Unexpectedly, tumors in p27−/− livers contained only slightly elevated Cdk2 kinase activity compared with normal livers. These results reveal a liver tumor suppressor role of p27 in this resistant mouse strain, and the need to further study the role of Cdk2 kinase in liver tumor promotion by p27 inactivation. © 2007 Wiley‐Liss, Inc.
A superoxide anion generator, pyrogallol, inhibits the growth of HeLa cells via cell cycle arrest and apoptosis
Authors: Kim Sang WooK , Han Yong Whan , Lee Soo Teik , Jeong Hey Jin , Kim Seong Hun , Kim In Hee , Lee Seung Ok , Kim Dae Ghon , Kim Suhn Hee , Kim Sung Zoo , Park Woo Hyun 
Published: July 2007

AbstractWe investigated the in vitro effects of pyrogallol on cell growth, cell cycle regulation, and apoptosis in HeLa cells. Pyrogallol inhibited the growth of HeLa cells with an IC50 of approximately 45 µM. Pyrogallol induced arrest during all phases of the cell cycle and also very efficiently resulted in apoptosis in HeLa cells, as evidenced by flow cytometric detection of sub‐G1 DNA content, annexin V binding assay, and DAPI staining. This apoptotic process was accompanied by the loss of mitochondrial transmembrane potential (ΔΨm), Bcl‐2 decrease, caspase‐3 activation, and PARP cleavage. Pan‐caspase inhibitor (Z‐VAD) could rescue some HeLa cells from pyrogallol‐induced cell death, while caspase‐8 and ‐9 inhibitors unexpectedly enhanced the apoptosis. When we examined the changes of the ROS, H2O2 or O in pyrogallol‐treated cells, H2O2 was slightly increased and O significantly was increased. In addition, we detected a decreased GSH content in pyrogallol‐treated cells. Only pan‐caspase inhibitor showing recovery of GSH depletion and reduced intracellular O level decreased PI staining in pyrogallol‐treated HeLa cells, which indicates dead cells. In summary, we have demonstrated that pyrogallol as a generator of ROS, especially O, potently inhibited the growth of HeLa cells through arrests during all phases of the cell cycle and apoptosis. © 2007 Wiley‐Liss, Inc.
Energy release rate for cracks in finite‐strain elasticity
Authors: Knees Dorothee , Mielke Alexander 
Published: July 2007

AbstractGriffith's fracture criterion describes in a quasistatic setting whether or not a pre‐existing crack in an elastic body is stationary for given external forces. In terms of the energy release rate (ERR), which is the derivative of the deformation energy of the body with respect to a virtual crack extension, this criterion reads: if the ERR is less than a specific constant, then the crack is stationary, otherwise it will grow.In this paper, we consider geometrically nonlinear elastic models with polyconvex energy densities and prove that the ERR is well defined. Moreover, without making any assumption on the smoothness of minimizers, we rigorously derive the well‐known Griffith formula and the J‐integral, from which the ERR can be calculated. The proofs are based on a weak convergence result for Eshelby tensors. Copyright © 2007 John Wiley & Sons, Ltd.
Experimental investigation of millimeter‐wave GaAs ted oscillators cooled to cryogenic temperatures
Authors: Rydberg Anders , Kollberg Erik 
Published: July 2007

AbstractThe output power and operating (bias) point for 80‐100‐GHz GaAs TED oscillators have been investigated for temperatures between 300 and 40d̀ K. It is shown experimentally that the power can be increased by as much as nearly four times by cooling the oscillator. The thermal design of the oscillator was studied for GaAs and InP TED oscillators.
On the design of an active circulator
Authors: Bahl Inder J. 
Published: July 2007

AbstractDesign of a fully monolithically integrable active circulator without any externally added circuit components is described in this paper. Two different configurations for active circulators using power dividers and Lange couplers are investigated. The circuit using Lange couplers indicates superior performance and is capable of providing O‐dB loss and return loss and isolation better than 16 dB and 23 dB, respectively, over an octave or higher bandwidth.
Cutoff characteristics of composite optical fibers
Authors: Atsuki Kazuhiko , Kaewsuriyathumrong Santi , Yamashita Eikichi 
Published: July 2007

AbstractThis paper applies an improved version of the point‐matching method for estimating the cutoff frequencies of the dominant mode of a class of polarization‐maintaining composite optical fibers and shows an existence condition for nonzero cutoff frequencies of the dominant mode.
Study of mesfets on P‐substrates and on thin P‐layers
Authors: El‐Ghazaly Samir , Itoh Tatsuo , Salmer George 
Published: July 2007

AbstractThe effect of doping of the P‐substrate on the performance of the submicron‐gate MESFET is simulated using a two‐dimensional computer model. It is observed that though increasing the substrate doping results in a better carrier confinement to the active layer, it reduces the drain current. To overcome this problem, a thin fully depleted P‐layer can be introduced between the active layer and the semiinsulating substrate.
Control of millimeter wave devices by optical mixing
Authors: Fetterman Harold R. , Ni Davi D. C. 
Published: July 2007

AbstractCoherent mixing of optical radiation from a tunable CW dye laser and a stabilized HeNe laser was used to generate broadband microwave signals beyond the Ka band in FETs, HEMTs, and the related devices. Comparing with direct modulation of the light signal, this technique enhances photoconductivity and frequency stability.
Determination of the transverse propagation delays in single‐gate GaAs Mesfets
Authors: Goel A. K. 
Published: July 2007

AbstractA computer‐efficient algorithm for the calculation of the transverse propagation delays in single‐gate GaAs MESFETs is presented. Electrode parasitic capacitances and the electrode contact and metallization resistances have been included in addition to the internal elements in the MESFET. The technique can be used for MESFETs with submicron gate lengths as well.
Contact effects in InP near‐micron transferred electron devices
Authors: Czekaj J. , Shaw M. P. , Grubin H. L. 
Published: July 2007

AbstractWe have performed an experimental and numerical investigation of near‐micron sized InP transferred electron devices having alloyed metal cathode “current‐limiting” contacts. Both a Boltzmann transport equation (BTE) and drift and diffusion analysis were used to simulate the dc and ac results. Both techniques were capable of predicting the dc and amplification characteristics, but only the BTE approach predicted the narrow large‐signal oscillatory bandwidth observed in the experiments. We found that: The devices behaved in a transit time oscillatory mode; subtle differences in contact conditions caused major change in device output frequency, power, and efficiency; the temperature dependence of the current‐voltage characteristic is a strong indicator of the potential device performance.
A versatile reflector antenna pattern computation method: Shooting and bouncing rays
Authors: Lee S. W. , Chou R. 
Published: July 2007

AbstractBased on shooting and bouncing geometrical optics rays, this paper describes an aperture integration method for computing the secondary pattern of reflector antennas. The method is versatile and flexible. Within the geometricdl optics accuracy, there is virtually no restriction on the number of reflectors, the coating material, radome, or the feed configurations. Pattern computations are shown for an antenna with six reflectors, coated with dielectric material and covered by a spherical radome.
An L‐band monolithic microwave receiver
Authors: Bharj Sarjit S. , Bayrun John , Dayal Har , Paradise Ronald 
Published: July 2007

AbstractAn L‐band receiver using gallium arsenide monolithic integrated technique has been developed for low‐cost manufacture. The front end receiver is comprised of an RF front‐end amplifier, a single‐pole‐double‐throw switch for antenna selection, a local oscillator buffer amplifier, phase splitters, and a double balanced mixer. This paper reports the design, fabrication, packaging, and testing of the complete receiver.
Mode determination of planar coupled millimeter‐wave oscillators by quasioptical injection locking
Authors: Stephan Karl D. , Young Song‐Lin 
Published: July 2007

AbstractIn the development of planar oscillator arrays for quasioptical power combining, it is desirable to know the relative phase of the individual oscillator currents or voltages. We present a simple quasioptical injection‐locking measurement which is used to determine the operating mode of a two‐device Ka‐band Gunn‐diode oscillator system.
Three‐dimensional finite‐element formulation for deterministic waveguide problems
Authors: Picon O. 
Published: July 2007

AbstractA finite‐element method for the analysis of 3D‐waveguide problems is formulated using a deterministic approach. The electric field is computed from the TE10excitation field by means of a variational formulation that satisfies divE= 0 even when field singularities exist.
Optimization of the charge distribution function on coupled microstrips by a dielectric layer
Authors: Lee Wei‐Yu , Wang Way‐Seen 
Published: July 2007

AbstractIn this article an optimization method is proposed in the determination of the charge distribution function of a variational expression for the line capacitance of coupled microstrips covered by a dielectric layer. The method is simple and easy for computer evaluation. Consistent results were obtained when compared with those of the previous work.
Error probability of optical PSK systems with nonlinear loop dynamics and postdetection filtering
Authors: Basch E. E. , Kearns R. F. , Brown T. G. 
Published: July 2007

AbstractWe describe a numerical approach to the problem of phase recovery in coherent optical communications systems corrupted by phase noise. Two advantages not present in previous treatments are the facts that the effects of the nonlinearity are treated exactly and a probability distribution for the filtered output is obtained without resorting to upper bounds. The results are applied to a sensitivity calculation for phase‐shift‐keyed systems.
Rf characteristics of a high‐temperature superconductive resonant strip in waveguide
Authors: Chang K. , Pandey R. K. , Skrehot M. K. , Li M. , Gilbert G. R. 
Published: July 2007

AbstractA resonant strip made of high‐temperature YBa2Cu3O6.5 + x with x < 0.5 superconductor was designed and tested in a X‐band (8‐12 GHz) waveguide. At room temperature no significant resonance was observed. A resonance appeared near 10.68 GHz at low temperature. The loaded Q was measured to be 750, comparable to that of a copper strip.
A dual six‐port network analyzer
Authors: Yeo S. P. , Chu M. C. 
Published: July 2007

AbstractA network analyzer consisting of two six‐port reflectometers was constructed for use over the WR90 bandwidth. Each six‐port reflectometer comprised a symmetrical five‐port junction and a directional coupler. Laboratory tests indicated that measurement accuracies of ± 0.01 in magnitude and ±2° in phase were obtainable for both reflection and transmission coefficients.
Local millimeter‐wave power transmitted through illuminated semiconductor panel scanned with strip of shadow
Authors: Rahnavard M. H. 
Published: July 2007

AbstractMoving‐spot‐illuminated semiconductor panels are used in millimeter‐wave image convertors. In order to know the performance of this system, it is required to know the response of illuminated semiconductor panels. In this article local millimeter‐wave power transmitted through an illuminated semiconductor panel scanned with a strip of shadow as a function of scanning velocity, width of the shadow strip, time, etc., are studied.
A markov chain approach for static field analysis
Authors: Fusco V. F. , Linden P. A. 
Published: July 2007

AbstractThe calculation of the static field that exists in many distributed electromagnetic systems is of prime importance since it allows preliminary design at microwave frequencies to be initiated. This article demonstrates how an absorbing Markow chain can be used to solve the Dirichlet problem, thereby yielding useful results such as field potentials, stored energy, and characteristic impedance.The theoretical basis for this method is developed, then applied to a shielded microstrip line in order to calculate line characteristic impedance. Some of the unique features of the absorbing Markov chain method will be discussed and its relationship to the probabilistic potential theory and finite‐difference techniques elaborated.The technique of absorbing Markov chains as discussed in this article represents a supplementary solution method to those currently in use and offers the possibility of detailed behavioral studies based on the movement of charged particles.
Polarization insensitive coherent detection using orthogonally polarized optical fields
Authors: Hodgkinson T. G. , Cook A. R. J. 
Published: July 2007

AbstractRecently reported polarization insensitive heterodyne detection schemes that use the properties of polarized light are all shown to be related to the basic concept of simultaneously using two different frequency, orthogonally polarized optical fields. The various system design options associated with this concept are compared in terms of receiver complexity.
Generalized coupled mode theory of curved multiwaveguide systems
Authors: Cheng Yue‐Hua , Lin Wei‐Gan 
Published: July 2007

AbstractA generalized coupled mode theory has been developed to analyze curved multiwaveguides from the reciprocity theorem. A simple relationship between local coupling coefficients and local nonorthogonal coefficients is given. Our theory takes account of the field deformation due to waveguide bending, and the nonorthogonality and phase interference between local guided modes in different bent waveguides. It is noted that the generalized coupled mode theory satisfies the reciprocity theorem and power conservation.
Numerical convergence in dichroic problems
Authors: Webb Kevin J. , Caroglanian Armen , Grounds Preston W. , Mittra Raj 
Published: July 2007

AbstractThe numerical convergence in the spectral domain formulation of dichroics is addressed using a specific example. The asymptotic forms of the inner products and the issue of relative convergence are discussed. Results from an experimental study are presented together with numerical data using two sets of basis functions.
Hard‐clipping joint transform correlator using a microchannel spatial light modulator
Authors: Yu F. T. S. , Song Q. W. , Suzuki Y. , Wu M. 
Published: July 2007

AbstractA programmable real‐time optical joint transform correlator that generates sharper autocorrelation peaks is presented. A microchannel spatial light modulator is utilized as the threshold hard‐clipping square‐law device. A liquid crystal television is used to display the input target and reference image. The basic principle of the system and a preliminary experimental result are given.
Optically reconfigured active phased array antennas
Authors: Daryoush A. S. , Choe B. 
Published: July 2007

AbstractFuture generations of phased array antennas for space‐based and airborne platforms are designed based on a large number of active T / R modules. The constructed radiating beam is degraded in the event of modules failure. Simulation results indicate that the control of frequency, interelement spacing, and the individual radiating element pattern alongside the more conventional technique of amplitude and phase can be used to reconfigure the desired radiating beam in the event of the active T / R module failure.
A dynamic model for printed circuit crossover interconnects
Authors: Yang Hung‐Yu , Alexopoulos Nicolaos G. 
Published: July 2007

AbstractCrossover printed conductors may be used as multilevel chip‐to‐chip interconnects for high‐frequency high‐speed circuits, in VLSI applications, microwave directional couplers, etc. A theoretical model for crossover interconnects is presented in this article. The model accounts for dispersion effects and radiation loss and it may be used for the design of maximum or minimum power transfer between interconnects.
Theory and design of stub tuned nonreciprocal stripline junctions and circulators
Authors: Xu Yansheng , Miao Jianyong 
Published: July 2007

AbstractIn this article a rigorous and effective analysis of microwave ferrite stub tuned stripline junctions and circulators is presented. By using the equivalent parallel plate waveguide and mode matching method, the eigenvalues and scattering parameters of the junction are calculated. A method of design of the stub tuned circulators is given, which is verified by the experimental results. Theoretical and experimental results show that this kind of circulator can be easily designed to have an octave bandwidth.
Beam transformation by defocused imaging lens
Authors: Chu T. S. , Gans M. J. 
Published: July 2007

AbstractThe effects of spherical aberration and beam truncation have been clarified in the beam transformation of laser radiation by a defocused imaging lens. Excellent agreement was obtained between calculated and measured patterns. Amplitude ripples of about 1 dB are primarily caused by interference between geometrical optic rays and edge diffraction rays.
Elastic multiple scattering by randomly distributed spherical scatterers
Authors: Wang Zhi‐Liang , Lin Wei‐Gan 
Published: July 2007

AbstractFrom the basic integral equation for multiple scattered fields, the expansions of the fields in terms of vector spherical wave functions, and the translational addition theorems of the vector spherical wave functions, a set of coupled linear equations has been derived for the expansion coefficients of elastic scattering fields by randomly distributed spherical scatterers. Thus, a new theory for this kind of problem is developed. Different from the other theories, this theory gives the multiple elastically scattered fields in all regions.
Microwave response of a hemt photoconductive detector
Authors: Claspy P. C. , Bhasin K. B. 
Published: July 2007

AbstractInterdigitated photoconductive detectors with 5‐μm geometry have been fabricated on HEMT material and their optical response characteristics at 820 nm have been examined at DC and in the frequency range of 2‐8 GHz. These have been compared with characteristics of similar 1‐μm devices on MESFET material. The shapes of the frequency responses were found to differ, but the useful bandwidth of both types of devices was found to be similar.
White‐light optical directional frequency false color coding—a new technique
Authors: Deekshatulu B. L. , Bajpai O. P. , Meenakshisundaram P. 
Published: July 2007

AbstractA real‐time white‐light processing technique for directional frequency false color coding based on optical signal parallel processing is described. The output colors are derived directly from the white‐light source. The procedure to record an output either as a parallel or serial processor is detailed. Experimental results are highlighted.
Standing wave effects in a symmetrical three‐line microstrip coupler with short‐circuited side lines
Authors: Faria J. A. Brandão 
Published: July 2007

AbstractThe spectral domain analysis of microstrip couplers with lateral ground strips can be conducted following two different approaches: assuming the lateral strips are continuously short‐circuited to ground or discretely bonded to the reference ground conductor at the coupler ends. In this paper, the second approach is used: The wave number and the characteristic admittance of the central strip propagation made of a coplanar three‐conductor microstrip transmission line are determined and shown to depend critically on the coupler length. The spatial evolution of microstrip voltages and currents inside the coupler is also determined and discussed. The results show that noticeable standing wave effects are present when the coupler length comes close to an integer multiple of one‐half wavelength.
Elastic and inelastic scattering by an arbitrary body filled with active molecules: Method of eigenfunction expansion in integral equation
Authors: Wang Zhi‐Liang , Lin Wei‐Gan 
Published: July 2007

AbstractThe integral equation method in [1] is extended to analyze the elastic and inelastic scattering from an arbitrary particle filled with active molecules, and at the same time, the field's correction is taken into account as the field point and source point are at the same location. The electromagnetic fields are expanded in terms of vector spherical wave functions, and the expansion coefficients can be solved from a set of coupled linear equations. Some numerical results and conclusions are given.