bluuebunny/crossref_metadata_2025 huggingface dataset:
PHOTOCHEMISTRY AND METAL CATALYSIS: STUDIES ON A FLAVIN SENSITIZED: OXIDATION OF ASCORBATE*
Authors: Homann Peter , Gaffron Hans
Published: January 2008

Summary This paper constitutes a study of the interaction between ascorbate, diketogulonate, manganous ion, oxygen and illuminated flavins (or other sensitizers). When ascorbate is chosen as the substrate, the resulting photoxidation assumes a peculiar two‐step course. This happens because traces of ascorbate inhibit the photoxidation of diketogulonate and oxygen retards the photoxidation of small amounts of ascorbate. Sensitized photo‐reactions which are inhibited by high concentrations of oxygen are affected by the addition of various organic compounds. Of these, the herbicides 3‐(p‐clilorophenyl)‐1,1‐dimethylurea (CMU) and 3‐(3, 4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU) interfere nearly exclusively with flavin sensitized photoreactions, while other inhibiting compounds tested, such as tryptophane and tyrosine, do not display a similar selectivity for only one dye. A second even more rigid specificity concerns the role of manganous ions. Diketogulonate is oxidized through the action of light excited flavin or of traces of alkali in the dark only when Mn++ is available. No other metal tested had this ability.

The response of flavin sensitized photoreactions to the addition of CMU or DCMU varies with the substrate being oxidized. With ascorbate and 2, 3‐diketogulonate as substrates in the presence of manganous ions, CMU reverses the inhibition by oxygen, but with ethylenediamine tetraacetic acid (EDTA) or triethylene tetramine (TETA) as substrates CMU acts as an inhibitor itself. With one exception all effects of CMU on flavin sensitized reactions, be they anaerobic bleaching or aerobic oxidations, were inhibitory. The one exception, the apparent promotion of manganese catalyzed photoxidations, may come about through the inhibition of competing reactions such as the quenching of light‐excited dyes by oxygen. At the same time it IS noteworthy that the manganese dependent photoxidation is refractory against CMU as inhibitor.

The conclusion is inescapable that herbicides like CMU form stable charge transfer complexes with excited flavin molecules. But simple complex formation is not sufficient to explain all of our findings on the basis of the two most frequently proposed reaction mechanisms for sensitized light reactions. We have had to modify them to make them fit the experiments here summarized.
ACTTON SPECTRA OF PHYTOCHROME IN VITRO*
Authors: Butler W. L. , Hendricks S. B. , Siegelman H. W.
Published: January 2008

Summary First‐order rate constants, Kλ, for the photochemical conversions of both forms of phytochrome, PR and PFR, were measured at various wavelengths between 300 and 800 nm. The product of the extinction coefficient, ε, and the quantum yield, ø, at any wave‐length, λ, could be determined from the value of Kλ and the mole fractions of PR and PFR present at the photostationary state set by λ. The determination of the action (εø) spectra required that the photostationary states in red and far‐red light be known. These were determined from the absorption spectra and kinetic data.
THE BLUE EMISSION FROM CIS‐STILBENES*
Authors: Lamola Angelo A. , Hammond George S. , Mallory Frank B.
Published: January 2008

Abstract— Under irradiation in glassy solution at 77°K cis‐stilbene shows a broad emission spectrum with a maximum at about 4180 Å. A similar emission is observed from 1,2‐diphenyl‐cyclopentene. The emission is shown to be fluorescence and is shown not to arise from either phenanthrene or the: intermediate (presumed to be a dihydrophenanthrene) involved in the photooxidation of cis‐stilbene to phenanthrene. The observations imply that, at least in a solid matrix, there is a barrier to rotation in the lowest excited singlet. Formation of the cyclic isomer, believed to be a dihydrophenanthrene, occurs on irradiation at room temperature but not at 77°K. Isomerization must provide a path for decay of excited singlets that becomes unavailable at low temperature. The possible general importance of such “chemical” decay mechanisms is discussed.
THE RELATIONSHIP BETWEEN CAROTENOID PIGMENTS AND RESISTANCE TO RADIATION IN NON‐PHOTOSYNTHETIC BACTERIA
Authors: Mathews Micheline M. , Krinsky Norman I.
Published: January 2008

Abstract— A radiation‐resistant Micrococcus sp. and a colorless mutant subject to gamma radiation were found to have identical killing curves. Similar results were obtained with ultraviolet light. However when exposed to visible light in the presence of the photosensitizer, toluidine blue, the pigmented wild‐type was unaffected whereas the colorless mutant was killed. Sarcina lutea and a colorless mutant were killed at similar rates following exposure to x‐rays and U.V. light, whereas previous studies have demonstrated that the pigmented wild‐type is protected against lethal photosensitizations by visible light. It is concluded that the effect of carotenoid pigments in radiation damage is limited to protecting cells against the lethal effects of visible light and is without effect at shorter wavelengths.
A SURVEY OF CHEMILUMINESCENCE IN BASE‐CATALYZED AUTOXIDATION REACTIONS
Authors: Berger A. W. , Driscoll J. N. , Pirog J. A.
Published: January 2008

Abstract— Relatively bright chemiluminescence has been observed in autoxidation reactions in basic, aprotic, ionizing media for selected acyloins, vinyl carbonyls, vinyl nitriles and polynuclear aromatic compounds. The indoles approach the brightness of the most efficient chemiluminescent compounds. The intensity of acyloin emission correlates qualitatively with the resonance stabilization of the intermediate radical anion. It is suggested that Chandross' oxidative excitation mechanism may be applicable to the acyloins and hydrocarbons.
CHEMILUMINESCENCE IN LIQUID SOLUTIONS: THE CHEMILUMINESCENCE OF LOPHINE AND ITS DERIVATIVES*
Authors: White Emil H. , Harding Maurice J. C.
Published: January 2008

Abstract— A number of derivatives and analogs of lophine (Ia) have been prepared in an effort to elucidate the chemiluminescence of this class of compounds. A hydroperoxide has been implicated as a reaction intermediate; intramolecular decomposition of this compound yields an excited singlet state of a diaroylarylamidine salt (IX). the light emitter in the reaction. Consistent with this view is the fact that in two cases the chemiluminescence emission matches the wavelength distribution in the fluorescence of the amidine salts. A brief discussion is given of the nature of chemiluminescence of reactions in solution.
QUELQUES OBSERVATIONS SUR LE DÈVELOPPEMENT DES CULTURES IN VITRO DE MOELLE DE TABAC EN PRÉSENCE D'AUXINE ET DE KINÉTINE, EN ÉCLAIRE‐MENT RELATIVEMENT MONOCHROMATlQUE
Authors: Beauchesne G.
Published: January 2008

Abstract— In a previous publication we have presented some results on tobacco pith tissue cultures grown in relatively monochromatic light (around 4350,5250, 6600 and 8000 Å).

This paper points out specially that cultures subjected to a continuous blue light period of 12 days only, followed by a darkness period of 29 days, grew no more than cultures exposed to the same radiations during the 41‐day period of the experiment.

The growth was only 67 per cent of that of tissues grown in the darkness.

The morphologic and histologic observations showed the same differences between the cultures grown in blue light conditions and the cultures grown in the other light conditions, as also reported elsewhere.

Observation of bud developement on stem segment cultures in vitro of willow, grown under these relatively monochromatic light conditions, together with these histologic studies, leads us to believe in a possible gibberelline action in blue light.
LE MÉTABOLISME DES ANTHOCYANES EN RELATION AVEC LA LUMIÈRE ET LA FLORAISON CHEZ PERILLA NANKINENSIS (LOUR.) DECNÉ
Authors: Schumacker R.
Published: January 2008

Abstract— Synthesis and degradation of anthocyanins in the leaves of Perilla nankinensis (S.D. plant) were studied in relation to photoperiod, light intensity and floral induction. No relation was found between anthocyanin degradation and floral induction as suggested earlier by Ermolaeva and Sironval. Discussion is opened on the significance of the observed variations of anthocyanin content in the leaves and on their relation with photosynthesis and respiration.
IMPORTANCE OF REORGANIZATION AND CORRELATION EFFECTS ON GOING TO EXCITED STATES*
Authors: GOODMAN LIONEL
Published: January 2008

Abstract— The results of two calculations on rearrangement of sigma and pi electrons and correlation energy changes as a result of electronic promotion are discussed. The conclusions are that reorganization of sigma and pi electrons and correlation effects resulting from electronic excitation which engenders significant charge distribution changes (e.g. electron loss or capture, n→π* promotions, charge transfer transitions) have important energetic consequences and should receive close attention from photochemists and photobiologists.

Se discuten los resultados obtenidos al calcular las reacomodaciones que sufren los electrones sigma y pi, y los cambios de energía producidos como resultado de las promociones electrónicas. Las conclusiones son; que la reorganización de los electrones sigma y pi, y los efectos de correlación que resultan de la excitación electrónica que produce cambios significativos en la distribución de carga (ejem.: captura o pérdida del electrón, promociones n –π*, transiciones con transferencia de carga) tiene consecuencias energéticas importantes, que deberían recibir una marcada atención por parte de fotoquímicos y fotobíologos.
THE BIOLOGICAL IMPORTANCE OF U.V.‐INDUCED DNA‐PROTEIN CROSS‐LINKING IN VIVO AND ITS PROBABLE CHEMICAL MECHANISM*
Authors: SMITH KENDRIC C.
Published: January 2008

Abstract— The increased sensitivity of Escherichia coli to killing by u.v. while frozen and the changes in sensitivity as a function of temperature during irradiation have been correlated with the increased production of DN A‐protein cross‐links and have been shown not to be related to thymine dimer production. These results provide yet another example where thymine dimers make little contribution to the u.v. inactivation of a biological system (but does not detract from the biological importance of thymine dimers in other systems). We have reported that uracil and cysteine can combine to form 5‐S‐cysteine, 6‐hydrouracil when a solution of these two compounds is irradiated with u.v. (2357 Å). This led us to offer this compound as a model for the mechanism by which DNA and protein are cross–linked in vivo. We have now extended our studies to the kinetics of the photochemical addition of 35S‐cysteine to various polynucleotides and to DNA. Selected rate constants for cysteine addition (μM cysteine/μM nucleotide involved /erg/mm2× 108) are as follows:

image

The rate constants for native and heat‐denaturated DNA can be accounted for by the summation of the rate constants for the appropriate polynucleotides. The addition of cysteine to RNA shows a biphasic response probably related to the amount of single‐stranded regions present. Preliminary results indicate that tyrosine and serine also add photochemically to DNA.

La pronunciada sensibilidad del Escherichia coli al ser irradiado por luz u.v. cuando esta congelado y los cambios en la sensibilidad con la temperatura durante la radiación han sido relacionados con el aumento en la produccion de uniones ADN‐proleina y se ha demostrado no tener relación con la formación de dímeros de la timina. Los resultados aquí presentados proveen otro ejemplo para ilustrar que los dímeros de la timina practicamente no contribyen a la inactivación con luz u.v. de un sistema biológico (pero no niega la importancia biológica de los dimeros de la timina en otros sistemas). Hemos reportado que el uracilo y la cisteina pueden combinarse para formar 5‐S‐cisteina. 6‐hidrouracilo cuando una solución de estos dos componentes es irradiada con luz u.v. (2537 Å). Esto nos conduce a presentar a este compuesto para explicar el mecanismo por el cual el ADN y la proteina se unen in vivo. En la actualidad hemos extendido nuestros estudios a la cinética de la adición fotoquimica de 35S‐cisteina a varios polinucleótidos y al ADN. Las constantes de velocidad para la adición de cisteina en (μM de cisteina/μM de nucleotido/erg/mm2× 108) son las siguientes:

image

Las constantes de velocidad para el ADN nativo y desnaturalizado por el calor pueden obtenerse sumando las constantes de velocidad de los polinucleótidos correspondientes. Algunos resultados preliminares indican que la tirosina y la senna tambien se adicionan fotoquímicamente al ADN.
Research on General and Axisymmetric Ellipsoidal Shells Used as Domes, Pressure Vessels, and Tanks
Authors: Krivoshapko S. N.
Published: January 2008

The principal advances in the design and construction, as well as the static, vibrational, and buckling analysis of thin-walled structures and buildings in the shape of general and axisymmetric ellipsoidal shells are summarized in this review. These shells are particularly useful as internally pressurized vessels or as heads and bottoms of cylindrical tanks and vessels. Reinforced concrete and structural steel domes of buildings, air-supported rubber-fabric shells, and underwater pressure vessels are also made in the form of ellipsoidal, shells. Knowing the geometry of ellipsoids, one can solve various problems in physics, optics, and so on. Basic results of theoretical and experimental investigations of the stress-strain state, buckling, and natural and forced vibrations contained in 209 references are presented in the review. The influence of temperature on the stress-strain state of the shells in question is also discussed. Some parts of the review are also devoted to an analysis of the literature on the stress-strain state of ellipsoidal and torispherical heads of pressure vessels with openings.
Fast, high‐resolution 3D dosimetry utilizing a novel optical‐CT scanner incorporating tertiary telecentric collimation
Authors: Sakhalkar H. S. , Oldham M.
Published: January 2008

This study introduces a charge coupled device (CCD) area detector based optical‐computed tomography (optical‐CT) scanner for comprehensive verification of radiation dose distributions recorded in nonscattering radiochromic dosimeters. Defining characteristics include: (i) a very fast scanning time of to acquire a complete three‐dimensional (3D) dataset, (ii) improved image formation through the use of custom telecentric optics, which ensures accurate projection images and minimizes artifacts from scattered and stray‐light sources, and (iii) high resolution (potentially ) isotropic 3D dose readout. The performance of the CCD scanner for 3D dose readout was evaluated by comparison with independent 3D readout from the single laser beam OCTOPUS™‐scanner for the same PRESAGE™ dosimeters. The OCTOPUS™ scanner was considered the “gold standard” technique in light of prior studies demonstrating its accuracy. Additional comparisons were made against calculated dose distributions from the ECLIPSE treatment‐planning system. Dose readout for the following treatments were investigated: (i) a single rectangular beam irradiation to investigate small field and very steep dose gradient dosimetry away from edge effects, (ii) a 2‐field open beam parallel‐opposed irradiation to investigate dosimetry along steep dose gradients, and (iii) a 7‐field intensity modulated radiation therapy (IMRT) irradiation to investigate dosimetry for complex treatment delivery involving modulation of fluence and for dosimetry along moderate dose gradients. Dose profiles, dose‐difference plots, and gamma maps were employed to evaluate quantitative estimates of agreement between independently measured and calculated dose distributions. Results indicated that dose readout from the CCD scanner was in agreement with independent gold‐standard readout from the OCTOPUS™‐scanner as well as the calculated ECLIPSE dose distribution for all treatments, except in regions within a few millimeters of the edge of the dosimeter, where edge artifact is predominant. Agreement of line profiles was observed, even along steep dose gradients. Dose difference plots indicated that the CCD scanner dose readout differed from the OCTOPUS™ scanner readout and ECLIPSE calculations by 10% along steep dose gradients and by 5% along moderate dose gradients. Gamma maps (3% dose‐difference and distance‐to‐agreement acceptance criteria) revealed agreement, except for regions within of the edge of the dosimeter where the edge artifact occurs. In summary, the data demonstrate feasibility of using the fast, high‐resolution CCD scanner for comprehensive 3D dosimetry in all applications, except where dose readout is required close to the edges of the dosimeter. Further work is ongoing to reduce this artifact.
Correction factors for low perturbation in vivo diodes used in the determination of entrance doses in high energy photon beams
Authors: Roberts Ralph , Philp Amanda
Published: January 2008

Purpose—Low perturbation diodes, with thin buildup caps, can be used to reduce perturbations to the delivered dose. The literature states that additional correction factors are required for low perturbation diodes, however, there are few reported studies into their use. This report measured the dose perturbations and correction factors for diodes with varying buildup cap thicknesses. Methods and materials—Scanditronix EDP15, EDD5, and EDD2 diodes were investigated. Dose perturbations and correction factors for field size, source‐surface distance (SSD), obliquity, and wedge were measured in megavoltage photon beams. Results—EDP15 produces a dose perturbation. EDD5 produces a perturbation between and . EDD2 perturbation is negligible. The variation of correction factors for the full buildup EDP15 diode is small and consistent with the literature. The low perturbation diode EDD2 has large correction factors. The field size correction factor varies from 1.38 to 0.87 for 10 MV. The SSD correction factor varies from 0.92 to 1.09 for 10 MV. At the maximum angle measured, the obliquity correction factor is 0.73 for 10 MV. Intermediate results were observed for the EDD5 diode. Conclusions—It is expected that it will be very difficult to achieve accurate in vivo dosimetry using the EDD2 diode. The EDD5 diode may represent a reasonable compromise between EDD2 and the full buildup EDP15. The EDD5 dose perturbation is small and the correction factors are not as large as for EDD2, so accurate in vivo dosimetry may be possible as long as the obliquity is below 45 degrees.
An optimization model and solution for radiation shielding design of radiotherapy treatment vaults
Authors: Newman Francis , Asadi–Zeydabadi Masoud
Published: January 2008

In radiation shielding design, one is usually faced with a set of conflicting goals that are navigated by an experienced physicist. If one has abundant space, the task is simplified because concrete is relatively inexpensive and will provide adequate shielding for high energy photons and neutrons, when applicable. However, if space is constrained (which is usually the case), the design becomes more difficult since one will likely have to employ combinations of steel, lead, and concrete, or other new materials—each with different properties and costs. Very experienced shielding designers can draw upon previous plans, but they do not know if their design is optimal in any sense. We have constructed a linear program that minimizes the cost of the shielding materials and minimizes the dose at the protection point or the shielding thickness subject to space constraints and to Federal or State regulations regarding the allowable exposure to individuals adjacent to the radiotherapy vault. In spite of what appears to be a simple model, the solution may require iterations of the optimization to arrive at the optimal solution.
X‐ray scattering in single‐ and dual‐source CT
Authors: Engel Klaus J. , Herrmann Christoph , Zeitler Günter
Published: January 2008

For medical imaging applications, such as cardiac imaging, dual‐source computed tomography (CT) improves the temporal resolution by the simultaneous use of two cone beams, which acquire twice as many projections as single‐source CT does within the same time interval. Besides this advantage, a drawback of such a system is additional x‐ray scatter originating from the extra (cross‐illuminating) cone beam. In this work, a comparison with single‐source CT images is performed under same‐dose conditions for two different thorax phantoms, and for different cone beam angles corresponding to a coverage of 20, 40, 80, and 160 mm on the rotation axis ( coverage). As a general result, the HU‐magnitude of scatter‐induced streak and cupping artifacts scale almost proportional to the illuminated volume. In dual‐source CT, cross scatter induces a further factor of almost 2 in the scaling of artifacts in comparison to single‐source CT. For all examined systems, the scatter‐induced noise reduces the contrast‐to‐noise ratio (CNR). In the case of an ideal scatter correction, the CNR is reduced even more, but contrast and CNR can be restored by an additional x‐ray dose. With a 32‐slice single‐source CT ( overage of 20 mm) taken as a reference, a corresponding dual‐source CT requires more dose to maintain the same CNR. A CT system with a coverage of 40, 80, and 160 mm requires , , and more dose in a single‐source configuration, respectively, and , , and more dose in a dual‐source configuration, respectively. In conclusion, a dual‐source CT is comparable to a single‐source CT with twice the coverage concerning image degradation by scatter.
Missing Baryons and the Warm-Hot Intergalactic Medium
Authors: Nicastro Fabrizio , Mathur Smita , Elvis Martin
Published: January 2008

Stars and gas in galaxies, hot intracluster medium, and intergalactic photo-ionized gas make up at most half of the baryons that are expected to be present in the universe. The majority of baryons are still missing and are expected to be hidden in a web of warm-hot intergalactic medium. This matter was shock-heated during the collapse of density perturbations that led to the formation of the relaxed structures that we see today. Finding the missing baryons and thereby producing a complete inventory of possibly the only detectable component of the energy-mass budget of the universe is crucial to validate or invalidate our standard cosmological model.
Effects of Moxibustion on the Recovery of Post-Stroke Urinary Symptoms
Authors: Yun Sang Pil , Jung Woo Sang , Park Sung Uk , Moon Sang Kwan , Park Jung Mi , Ko Chang Nam , Cho Ki Ho , Kim Young Suk , Bae Hyung Sup
Published: January 2008

This study was conducted to test the effectiveness of moxibustion therapy for patients with post-stroke urinary symptoms using International Prostate Symptom Score (IPSS). Stroke patients with urinary symptoms were enrolled and assigned into the moxibustion group (MO group) and the control group by stratified randomization. The MO group received moxibustion treatment on Zhong-Ji (CV-3), Guan-Yuan (CV-4) and Qi-Hai (CV-6) for 10 days, and the control group did not receive it. The effectiveness of urinary symptoms and activities of daily living were measured by IPSS and Barthel Index (BI), respectively. These scales were examined by an independent blinded neurologist before treatment, and 10 days after therapy. Thirty nine subjects (20 in the MO group and 19 in the control group) were included in the final analysis. The MO group showed more improvement on urinary symptoms than the control group. In conclusion, we suggest that moxibustion on Zhong-Ji (CV-3), Guan-Yuan (CV-4) and Qi-Hai (CV-6) is effective to post-stroke urinary symptoms.
A Method of Selecting Acupoints for Acupuncture Treatment of Peripheral Facial Paralysis by Thermography
Authors: Zhang Dong
Published: January 2008

The purpose of this study is to select acupoints for acupuncture treatment of peripheral facial paralysis according to the temperature on the face of the patient detected by thermogram, to determine an objective acupoint selection method for acupuncture treatment. In the test group of 60 cases of facial paralysis, the infrared thermogram on the face was detected at the first visit, and then acupuncture was given at the acupoints on the affected side with a temperature difference of over 0.5°C from the healthy side for one therapeutic course, and in each successive course the acupoints were re-determined according to the results of thermogram examination and were administrated till the end of the total therapeutic course, and 120 cases of the control group were treated with acupuncture at conventionally selected acupoints. The results showed that the cured and basically cured rate was 90.0% (54 cases) in the test group and 77.5% (93 cases) in the control group with a significant difference between the two groups ( p < 0.05); and the total sessions of acupuncture were less and the course of treatment was shorter in the test group than those in the control group (both p < 0.001). The utilization rate of the acupoints selected by facial thermogram in the test group was in order of Dicang (ST 4, 92.3%), Yingxiang (LI 20, 90.6%), Taiyang (EX-HN 5, 85.5%), Yangbai (GB 14, 76.6%), Quanliao (SI 18, 72.3%), and so on. In conclusion, acupuncture at the acupoints selected by thermogram for treatment of facial paralysis in the cured rate, the therapeutic course and sessions of acupuncture is significantly superior to acupuncture at the conventionally selected acupoints, and the thermogram-aided acupoint selection method is beneficial to objectivity and modernization of acupoint selection for acupuncture and moxibustion treatments.
N-Methyl-D-Aspartate Antagonist Inhibits NR-1 Subunit Phosphorylation of the Spinal N-Methyl-D-Aspartate Receptor Induced by Low Frequency Electroacupuncture
Authors: Kang Byeol-Rim , Ahn Chang-Beohm , Choi Byung-Tae
Published: January 2008

We investigated whether the 2 Hz electroacupuncture (EA) analgesia is associated with phosphorylation of N-methyl-D-aspartate receptor (NMDAR) NR-1 subunits and NMDAR antagonism in the lumbar spinal cord of rats. EA stimulation produced an increase of serine phosphorylation of NMDAR NR-1 subunits in the spinal cord as compared with normal conditions. However, the intrathecal injection of NMDAR antagonist D-2-amino-5-phosphonopentanoic acid significantly prevented serine phosphorylation of NMDAR NR-1 subunits induced by EA stimulation in the dorsal horn of spinal cord. These results indicate that EA analgesia by stimulation of peripheral nerves may be involved in an increase of NR-1 serine phosphorylation in the dorsal horn of the spinal cord.
Effect and Mechanism of Ligustrazine on Th1/Th2 Cytokines in a Rat Asthma Model
Authors: Xiong Liang , Fang Zheng-Yu , Tao Xiao-Nan , Bai Ming , Feng Gang
Published: January 2008

Ligustrazine is an alkaloid isolated from the rhizome of Chuanxiong (Ligusticum chuanxiong Hort), which is known to possess antioxidant, anti-inflammatory, anti-fibrosis and immunomodulative effects. It is used clinically to treat asthma as an assistant therapy of glucocorticoid. The purpose of this study was to explore the effects of intraperitoneal ligustrazine on Th1/Th2 cytokines in a rat asthma model and the underlying mechanism. SD rats were sensitized and challenged with ovalbumin (OVA) to establish an asthmatic model. Within 24 hours after the last ovalbumin challenge, changes in airway histology were observed. The concentrations of IL-4 and IFN-γ in bronchoalveolar lavage fluid (BALF) were measured by enzyme linked immunosorbent assay (ELISA). The protein expressions of GATA-3 and T-bet in lung were measured by Western blot. The results showed that an increase of Th2 cytokine and an inhibition of Th1 cytokine were accompanied by an increased expression of GATA-3 protein and a decreased expression of T-bet protein in rat asthmatic airways compared to those in normal control group. Intraperitoneal ligustrazine administration could significantly lower the level of IL-4 in BALF and the expression of GATA-3 protein in lung and also increase the level of IFN-γ and T-bet in asthmatic rats, resulting in a decreased percentage of eosinophils (EOS) in BALF and ameliorated airway inflammatory cell infiltration. In conclusion, ligustrazine inhibits OVA induced airway inflammation by modulating key master switches GATA-3 and T-bet that result in reversing the Th2 cytokine patterns in asthma.
Tetramethylpyrazine Inhibits Angiotensin II-Increased NAD(P)H Oxidase Activity and Subsequent Proliferation in Rat Aortic Smooth Muscle Cells
Authors: Wong Kar-Lok , Wu King-Chuen , Wu Rick Sai-Chuen , Chou Yu-Hsiang , Cheng Tzu-Hurng , Hong Hong-Jye
Published: January 2008

Tetramethylpyrazine (TMP) is the major component extracted from the Chinese herb, Chuanxiong, which is widely used in China for the treatment of cardiovascular problems. The aims of this study were to examine whether TMP may alter angiotenisn II (Ang II)-induced proliferation and to identify the putative underlying signaling pathways in rat aortic smooth muscle cells. Cultured rat aortic smooth muscle cells were preincubated with TMP and then stimulated with Ang II, [3H]-thymidine incorporation and the ET-1 expression was examined. Ang II increased DNA synthesis which was inhibited by TMP (1-100 μM). TMP inhibited the Ang II-induced ET-1 mRNA levels and ET-1 secretion. TMP also inhibited Ang II-increased NAD(P)H oxidase activity, intracellular reactive oxygen species (ROS) levels, and the ERK phosphorylation. Furthermore, TMP and antioxidants such as Trolox and diphenylene iodonium decreased Ang II-induced ERK phosphorylation, and activator protein-1 reporter activity. In summary, we demonstrate for the first time that TMP inhibits Ang II-induced proliferation and ET-1, partially by interfering with the ERK pathway via attenuation of Ang II-increased NAD(P)H oxidase and ROS generation. Thus, this study delivers important new insight in the molecular pathways that may contribute to the proposed beneficial effects of TMP in cardiovascular disease.
VECTOR SCHWINGER MODEL WITH A PHOTON MASS TERM: GAUGE-INVARIANT REFORMULATION, OPERATOR SOLUTIONS AND HAMILTONIAN AND PATH INTEGRAL FORMULATIONS
Authors: KULSHRESHTHA USHA
Published: January 2008

We consider the vector Schwinger model (VSM) describing two-dimensional electrodynamics with massless fermions, where the left-handed and right-handed fermions are coupled to the electromagnetic field with equal couplings, with a mass term for the U(1) gauge field and then study its operator solutions and the Hamiltonian and path integral formulations. We emphasize here that although the VSM has been studied in the literature rather widely but only without a photon mass term (which was a consequence of demanding the regularization for the VSM to be gauge-invariant (GI)). The VSM with a photon mass term is seen to be a gauge-noninvariant (GNI) theory. Using the standard Stueckelberg formalism we then construct a GI theory corresponding to the proposed GNI model. From this reformulated GI theory, we further recover the physical contents of the proposed GNI theory under a very special gauge choice. The theory proposed and studied here presents a new class of models in the two-dimensional quantum electrodynamics with massless fermions but with a photon mass term.
Interview with Tina Blaine
Authors: Lee Newton , Blaine Tina
Published: January 2008

Tina Blaine is a faculty member at Carnegie Mellon University's Entertainment Technology Center. Tina uses science and technology to explore new interface designs for gaming, collective music-making and interactive media with her graduate students. As a musical interactivist at Interval Research, she led a development team in the creation of a collaborative audiovisual instrument known as the Jam-O-Drum, now on permanent exhibit at the Experience Music Project in Seattle. An energetic composer and multiinstrumentalist, she has written music for NPR, video games, TV and documentary soundtracks. In the video interview, you will hear Tina's answers to the following questions:

1. What do you think about future human-computer interface in interactive media?

2. What do you think about using artificial intelligence to create new music or to mimic famous composers?

3. How do you see the future of music in 10 years? More new instruments, new sounds, or something entirely different?

4. If you have a 10-million dollar research fund to do anything you like, what would you do?

5. You are very much involved in volunteer service and community outreach, what is your favorite volunteer work?
Usability and usage of iTV services
Authors: Bernhaupt Regina , Obrist Marianna , Tscheligi Manfred
Published: January 2008

How users experience interactive TV (iTV) is determined by various factors; usability is a major one. In industry, usability is often seen as the key element that determines acceptance of new technologies by users. We present some of the results of an MHP-based (Multimedia Home Platform) iTV field trial in Salzburg, Austria concerning usability issues and iTV usage.

We give an introduction to the field trial and an overview of its methods to ensure usability of iTV services and to measure their use. We present results from a usability test, give design recommendations, and discuss whether using iTV is an active or a passive user experience.
Multimodal multiplayer tabletop gaming
Authors: TSE EDWARD , GREENBERG SAUL , SHEN CHIA , FORLINES CLIFTON
Published: January 2008

There is a large disparity between the rich physical interfaces of co-located arcade games and the generic input devices seen in most home console systems. In this article we argue that a digital table is a conducive form factor for general co-located home gaming as it affords: (a) seating in collaboratively relevant positions that give all equal opportunity to reach into the surface and share a common view; (b) rich whole-handed gesture input usually seen only when handling physical objects; (c) the ability to monitor how others use space and access objects on the surface; and (d) the ability to communicate with each other and interact on top of the surface via gestures and verbal utterance. Our thesis is that multimodal gesture and speech input benefits collaborative interaction over such a digital table. To investigate this thesis, we designed a multimodal, multiplayer gaming environment that allows players to interact directly atop a digital table via speech and rich whole-hand gestures. We transform two commercial single-player computer games, representing a strategy and simulation game genre, to work within this setting.
IMMERSCOM 2007
Authors: Lee Newton
Published: January 2008

IMMERSCOM is the first international conference that focuses on bridging the traditional gap between immersive technologies and networking for the capturing, processing, analyzing, transmitting and enabling the remote fruition of objects, environments, and bio-entities.
CyberGames 2007
Authors: Lee Newton
Published: January 2008

The Third International Conference on Games Research and Development 2007 (CyberGames 2007) will be held during 10-11 September 2007 at the Manchester Metropolitan University, United Kingdom
EURO ITV 2007
Authors: Lee Newton
Published: January 2008

Following on from previous conferences, the steering committee of EuroITV has decided to hold the 5th European Interactive TV conference in Amsterdam,the Netherlands. EuroITV brings together researchers and practitioners from diverse disciplines that include human-computer interaction, media studies, computer science, telecommunications, audiovisual design and management. The organizing committee invites you to submit original high quality papers addressing the special theme and the topics, for presentation at the conference and inclusion in the proceedings.
The gameplay visualization manifesto
Authors: Joslin Simon , Brown Ross , Drennan Penny
Published: January 2008

As massively multiplayer online games gain popularity, there has been a concomitant increase in their size and complexity, both technically and in terms of player usage. Quality assurance for such games takes up a major component of the development budget due to the painstaking work required to ensure the best possible gameplay. This article presents a new framework for the process of visualizing online game-play data. Major components such as an event model and data acquisition infrastructure are derived. Interface and implementation factors are also explored, including in-situ game interface approaches. We also expect that this framework can be modified for all genres of gaming that require an understanding of complex game-play.
You oughta be in pictures
Authors: Davison Chris
Published: January 2008

A golden age of old worlds, new worlds and hybrids.
The centrality and prestige of CACM
Authors: Polites Greta L. , Watson Richard T.
Published: January 2008

Journal rankings identify the most respected publications in a field, and can influence which sources to read to remain current, as well as which journals to target when publishing. Ranking studies also help track the progress of the field, identifying core journals and research topics, and tracking changes in these topics and perceptions over time. Past journal ranking studies have consistently found
Communications of the ACM
(CACM) to be very highly respected within the IS discipline. However, the exact nature of its relationships to other IS journals has not been thoroughly examined. In this article, we report a social network analysis (SNA) of 120 journals for the purpose of exploring in detail CACM's position within the IS journal network.
Digging CACM
Authors: Armour Phillip G.
Published: January 2008

An archeological view of a classic.
Back to experimentation
Authors: Freeman Peter A.
Published: January 2008

Three forward-looking projects depend on experimentation under real-world conditions.
From academia to the editorship
Authors: Cohen Jacques
Published: January 2008

Communications
has always had a special meaning to me since the beginning of my career, both professionally and personally. My fascination with computers started in the late 1950s when I was pursuing my doctoral degree at the University of Illinois, Urbana-Champaign. The
Illiac-I
was among the early computers built in the U.S. and I had the privilege to use it extensively in my dissertation.
CACM
Authors: Vardi Moshe Y.
Published: January 2008

The French adage "Plus ça change, plus c'est la même chose," or, the more things change, the more they stay the same, still rings true today. Reading over the essays of my predecessors, one recognizes the thread that runs through all of them, which is the constant need of CACM to reinvent itself. In fact, I discovered an April 24, 1964 report from a Commission of Thoughtful Persons to the ACM Council that stated "It was felt that
Communications
was becoming too much of a journal and that a re-evaluation is in order." I suspect this ongoing need to rethink CACM, a flagship publication for professionals working in a fast-moving and ever-changing field, will stay with us for the foreseeable future.
Hacking intellectual property law
Authors: Samuelson Pamela
Published: January 2008

Considering how intellectual property law has evolved in response to advances in computing technologies.
Introduction
Authors: Crawford Diane
Published: January 2008

A preview of things to come.
MapReduce
Authors: Dean Jeffrey , Ghemawat Sanjay
Published: January 2008

MapReduce is a programming model and an associated implementation for processing and generating large datasets that is amenable to a broad variety of real-world tasks. Users specify the computation in terms of a
map
and a
reduce
function, and the underlying runtime system automatically parallelizes the computation across large-scale clusters of machines, handles machine failures, and schedules inter-machine communication to make efficient use of the network and disks. Programmers find the system easy to use: more than ten thousand distinct MapReduce programs have been implemented internally at Google over the past four years, and an average of one hundred thousand MapReduce jobs are executed on Google's clusters every day, processing a total of more than twenty petabytes of data per day.
Technical perspective: finding a good neighbor, near and fast
Authors: Chazelle Bernard
Published: January 2008

You haven't read it yet, but you can already tell this article is going to be one long jumble of words, numbers, and punctuation marks. Indeed, but look at it differently, as a text classifier would, and you will see a single point in high dimension, with word frequencies acting as coordinates. Or take the background on your flat panel display: a million colorful pixels teaming up to make quite a striking picture. Yes, but also one single point in 106-dimensional space--that is, if you think of each pixel's RGB intensity as a separate coordinate. In fact, you don't need to look hard to find complex, heterogeneous data encoded as clouds of points in high dimension. They routinely surface in applications as diverse as medical imaging, bioinformatics, astrophysics, and finance.
ITIL
Authors: Greiner Lynn
Published: January 2008

The struggle to keep our IT ducks in a row (or even, some days, to find the wretched fowl!) gets tougher and tougher as infrastructures become more complex. As in the spaghetti code our programming teachers scolded us about, we touch one spot, and something wiggles in an unexpected place across the room.
I ❤ Vista
Authors: Weiss Aaron
Published: January 2008

Throughout the blogosphere and IT media, the consensus is clear: Windows Vista is a horribly botched operating system which is painfully difficult to use, lacks anything new or useful, hardly even functions at all, and can cause sores, rashes, and unexplained itching.
Encouraging speech and vocalization in children with autistic spectrum disorder
Authors: Hailpern Joshua
Published: January 2008

Technology can improve the life of those with Autistic Spectrum Disorder (ASD). Specifically, some children with ASD are not fortunate enough to acquire the ability to communicate with language on their own. With language being an important method of communication, socialization, and interacting with the world, these children need researchers to develop new solutions to help teach vocalization and speech. Without speech, these children will have difficulty communicating their needs, wants, and emotions, as well as being able to function within society at large. This paper examines the existing HCI research on ASD, as well as proposes a new direction for investigation.
Foreword
Authors: Marsan Marco Ajmone , Shenoy Prashant
Published: January 2008

Performance 2007, the 26-th International Symposium on Computer Performance, Modeling, Measurements, and Evaluation was held in Cologne, Germany, on October 2--5, 2007. Like in the past, in addition to the main technical program, a poster session was organized to present and discuss ongoing or recent research work in an informal setting.

A total of 11 posters were selected for presentation during the conference by the Performance 2007 Technical Program Committee. This special issue of
Performance Evaluation Review
consists of the extended abstracts of these posters, which cover a wide range of topics in the area of performance evaluation, analytical modeling and simulation of computer systems and communication networks.
Predicting packet loss statistics with hidden Markov models
Authors: Silveira Fernando , de Souza e Silva Edmundo
Published: January 2008

A number of applications can benefit from estimating future loss statistics. For instance, if the end-to-end loss characteristics of a path can be well approximated in advance, then a media streaming application could adapt its transmission parameters in order to deliver data with an acceptable quality to the user. In this work, we present a framework for adaptive prediction using hidden Markov models (HMMs). We propose a new class of hidden Markov models whose parameter values can be efficiently computed as compared to general HMMs. We also develop methods for predicting two measures of interest from HMMs, and perform experiments over a set of packet traces to assess the goodness of these predictions. Finally, we apply our prediction framework to dynamically select a forward error correction (FEC) scheme for media streaming. Using real Internet packet traces we evaluate the performance of our approach by emulating a VoIP tool. The PESQ algorithm is applied to assess the perceptual speech quality before and after the dynamic FEC selection. Our results show that the prediction-based approach achieves significant quality improvements with a small increase in the average transmission rate.
A note on source models for speech traffic
Authors: Menth Michael , Binzenhöfer Andreas , Mühleck Stefan
Published: January 2008

Speech traffic is often used in simulations to evaluate the performance of control mechanisms in communication networks. Therefore, trustworthy models are required that capture the fundamental statistical properties of typical voice sources. The G.723.1 codec produces on/off traffic streams with fixed size packets. The iSAC codec strongly periodic packet streams with variable packet sizes. We propose new models for the traffic output of both codecs and show that their queuing properties are in good accordance with those of original traffic traces, while existing traffic models, that are frequently used in literature, lead to significant discrepancies.
Capacity planning, quality of service and price wars
Authors: Dube Parijat , Touati Corinne , Wynter Laura
Published: January 2008

We model the relationship between capacity, Quality of Service (QoS) and offered prices of service providers in a competitive e-services market. Capacity and QoS are linked through simple queueing formulae while QoS and price are coupled through distributions on customer preferences. We study the sensitivity of market share of providers to price, capacity and market size. We revisit the notion of "price wars" that has been shown to lead to zero profits for all providers and conclude that our more general model does admit some form of anomalous behavior, but which need not lead to zero profits.
Performance impacts of autocorrelated flows in multi-tiered systems
Authors: Mi Ningfang
Published: January 2008

We focus on the general problem of capacity planning and performance prediction of multi-tiered systems. Workload characterization studies of such systems usually examine the stochastic characteristics of arrivals to the system and wait/service times at various tiers aiming at bottleneck identification, diagnosing the conditions under which bottlenecks are triggered, and assisting the development of resource management policies to improve performance or provide service level provisioning.
Resource co-allocation using advance reservations with flexible time-windows
Authors: Kaushik Neena , Figueira Silvia , Chiappari Stephen A.
Published: January 2008

Co-allocations require the availability of more than one resource for utilization in a time interval. We show that co-allocations increase the blocking probability and analyze the use of flexible windows to lower blocking probability in spite of co-allocations.
Tandem queue with server slow-down
Authors: Miretskiy D. I. , Scheinhardt W. R. W. , Mandjes M. R. H.
Published: January 2008

We study how rare events happen in the standard two-node tandem Jackson queue and in a generalization, the socalled slow-down network, see [2]. In the latter model the service rate of the first server depends on the number of jobs in the second queue: the first server slows down if the amount of jobs in the second queue is above some threshold and returns to its normal speed when the number of jobs in the second queue is below the threshold. This property protects the second queue, which has a finite capacity
B
, from overflow. In fact this type of overflow is precisely the rare event we are interested in. More precisely, consider the probability of overflow in the second queue before the entire system becomes empty. The starting position of the two queues may be any state in which at least one job is present.