Transcriptional activation of Epstein-Barr virus BRLF1 by USF1 and Rta

During its lytic cycle, Epstein-Barr virus (EBV) expresses Rta, a factor encoded by BRLF1 that activates the transcription of viral lytic genes. We found that upstream stimulating factor (USF) binds to E1, one of the five E boxes located at - 79 in the BRLF1 promoter (Rp), to activate BRLF1 transcription. Furthermore, Rta was shown to interact with USF1 in coimmunoprecipitation and glutathione S-transferase (GST)-pulldown assays, and confocal laser-scanning microscopy further confirmed that these two proteins colocalize in the nucleus. Rta was also found to bind with the E1 sequence in a biotin-labelled E1 probe, but only in the presence of USF1, suggesting that these two proteins likely form a complex on E1. We subsequently constructed p188mSZ, a reporter plasmid that contained the sequence from - 188 to +5 in Rp, within which the Sp1 site and Zta response element were mutated. In EBV-negative Akata cells cotransfected with p188mSZ and plasmids expressing USF1 and Rta, synergistic activation of Rp transcription was observed. However, after mutating the E1 sequence in p188mSZ, USF1 and Rta were no longer able to transactivate Rp, indicating that Rta autoregulates BRLF1 transcription via its interaction with USF1 on E1. This study showed that pUSF1 transfection after EBV lytic induction in P3HR1 cells increases Rta expression, indicating that USF1 activates Rta expression after the virus enters the lytic cycle. Together, these results reveal a novel mechanism by which USF interacts with Rta to promote viral lytic development, and provide additional insight into the viral-host interactions of EBV.

High-performance green flexible electronics based on biodegradable cellulose nanofibril paper

Today's consumer electronics, such as cell phones, tablets and other portable electronic devices, are typically made of non-renewable, non-biodegradable, and sometimes potentially toxic (for example, gallium arsenide) materials. These consumer electronics are frequently upgraded or discarded, leading to serious environmental contamination. Thus, electronic systems consisting of renewable and biodegradable materials and minimal amount of potentially toxic materials are desirable. Here we report high-performance flexible microwave and digital electronics that consume the smallest amount of potentially toxic materials on biobased, biodegradable and flexible cellulose nanofibril papers. Furthermore, we demonstrate gallium arsenide microwave devices, the consumer wireless workhorse, in a transferrable thin-film form. Successful fabrication of key electrical components on the flexible cellulose nanofibril paper with comparable performance to their rigid counterparts and clear demonstration of fungal biodegradation of the cellulose-nanofibril-based electronics suggest that it is feasible to fabricate high-performance flexible electronics using ecofriendly materials.

Mechanical properties of silicon carbide nanowires: effect of size-dependent defect density

This paper reports quantitative mechanical characterization of silicon carbide (SiC) nanowires (NWs) via in situ tensile tests inside scanning electron microscopy using a microelectromechanical system. The NWs are synthesized using the vapor-liquid-solid process with growth direction of ⟨111⟩. They consist of three types of structures, pure face-centered cubic (3C) structure, 3C structure with an inclined stacking fault (SF), and highly defective structure, in a periodic fashion along the NW length. The SiC NWs are found to deform linear elastically until brittle fracture. Their fracture origin is identified in the 3C structures with inclined SFs, rather than the highly defective structures. The fracture strength increases as the NW diameter decreases from 45 to 17 nm, approaching the theoretical strength of 3C SiC. The size effect on fracture strength of SiC NWs is attributed to the size-dependent defect density rather than the surface effect that is dominant for single crystalline NWs.

Highly stretchable carbon nanotube transistors with ion gel gate dielectrics

Field-effect transistors (FETs) that are stretchable up to 50% without appreciable degradation in performance are demonstrated. The FETs are based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes (CNTs) as the channel, a flexible ion gel as the dielectric, and buckled metal films as electrodes. The buckling of the CNT film enables the high degree of stretchability while the flexible nature of the ion gel allows it to maintain a high quality interface with the CNTs during stretching. An excellent on/off ratio of >10(4), a field-effect mobility of 10 cm(2) · V(-1) · s(-1), and a low operating voltage of <2 V are achieved over repeated mechanical cycling, with further strain accommodation possible. Deformable FETs are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins.

Accelerating effects of nonviable Staphylococcus aureus, its cell wall, and cell wall peptidoglycan

We have previously reported that local application of viable Staphylococcus aureus dramatically accelerates wound healing, but viable Staphylococcus epidermidis does not. Because the S. aureus effect occurred in the absence of infection and because the cell walls of the two bacterial species differ, we hypothesized that nonviable S. aureus, its cell wall, and its cell wall component(s) would accelerate healing. Nonviable S. aureus was prepared by chemical and physical means, and its cell wall and peptidoglycan was prepared from heat-killed cultures. In a large number of experiments, nonviable S. aureus (independent of the strain's protein A content), its cell wall, and peptidoglycan when instilled locally at the time of wounding each significantly increased the breaking strength of rat skin incisions (tested both in the fresh state and after formalin fixation). These agents also enhanced subcutaneous polyvinyl alcohol sponge reparative tissue collagen accumulation, generally by a factor of two. Histologic features of treated and control incisions were similar. In contrast, the reparative tissue of treated sponges contained more neutrophils, macrophages, capillaries, and collagen. These experimental data thus confirm our previous studies, as well as our hypothesis, and extend these observations of enhanced wound healing to specific fractions of the bacterial cell wall.

Molecular mechanisms underlying wound healing acceleration by Staphylococcus aureus peptidoglycan

Molecular mechanisms involved in wound healing acceleration by Staphylococcus aureus peptidoglycan were investigated with the use of polyvinyl alcohol sponges implanted under the dorsal skin of rats. Total collagen and RNA content and messenger RNA levels of alpha1(I) and alpha1(III) procollagen, transforming growth factor-beta1, and matrix metalloproteinase-1 were analyzed in saline solution- and S. aureus peptidoglycan-inoculated sponges at 4, 7, 14, and 21 days after implantation. S. aureus peptidoglycan-inoculated sponges on the fourth and seventh post-operative day were surrounded and penetrated by a thick capsule of reparative connective tissue. They were considerably heavier and contained more collagen and total RNA than saline solution-inoculated sponges. Histologically, the S. aureus peptidoglycan-inoculated sponges early on contained a denser infiltrate of polymorphonuclear cells than saline solution-inoculated sponges, and later fibroblasts, macrophages, collagen, and newly formed blood vessels were more abundant in the S. aureus peptidoglycan sponges. Matrix metalloproteinase-1 messenger RNA expression was elevated at 4 days in both sponge types. However, although matrix metalloproteinase-1 mRNA levels decreased to undetectable levels by 14 days in saline solution-inoculated sponges, they remained elevated throughout the 21-day study period in S. aureus peptidoglycan-inoculated sponges. No other significant differences in the parameters analyzed were detected. These results suggest that S. aureus peptidoglycan induces an accelerated but normal wound healing process in which the markedly increased early deposition of connective tissue is rapidly remodeled likely because of a sustained expression of matrix metalloproteinase-1.

Efficient heating with a controlled microwave field

To uncover the intriguing non-thermal microwave effect, an experiment was conducted using an amplifier rather than an oscillator as the radiation source, which was injected into an applicator with strong electromagnetic field enhancement. The characteristics of the applicator are discussed and the enhancement of the microwave field is illustrated and explained. Thermal distribution is simulated based on the calculated microwave field profile. It was demonstrated that the proposed system heated a SiC susceptor to a temperature of 637 °C with the input power of 60 W. The reasons for such an efficient heating are discussed.

X-ray microfabrication and measurement of a terahertz mode converter

Mode converters are critical for frequency-tunable terahertz gyrotrons. This study reports the development of a broadband TE(02) mode converter centered at 0.2 THz. An octafeed sidewall coupling structure was employed and the mode purity was analyzed. The converter was built using the technique of x-ray microfabrication. The x rays irradiated on the SU-8 resist and generated a template of very high thickness of 1.295 mm. Pulse electroplating technique was used to deposit copper on the structure along the template. The parts then went through precise machining and the residual resist was removed via high-flux radical etching. A computer-aided diagnostic system was introduced to measure the performance of the converter. Results suggest that the frequency response of resistivity should be taken into consideration for the devices in terahertz region.

Comparison of photodegradative efficiencies and mechanisms of Victoria Blue R assisted by Nafion-coated and fluorinated TiO2 photocatalysts

The purposes of this research were to study the effects of two modified photocatalysts, Nafion-coated TiO(2) and fluorinated TiO(2), and photocatalytic degradation of Victoria Blue R in aqueous solution. Photocatalytic degradation of Victoria Blue R was accelerated by the modified photocatalysts. Bulk and surface characterizations of the resulting powders were carried out. Attachment of the anions to the TiO(2) surface using the Nafion-coated-TiO(2) possibly results in increased adsorption of the cationic dye, and the degradation rate is larger for the cationic dye. It was found that Victoria Blue R on the two illuminated TiO(2) surfaces underwent very different changes. To obtain a better understanding on the mechanistic details of this modified-TiO(2)-assisted photodegradation of the Victoria Blue R dye with UV irradiation, a large number of intermediates of the process were separated, identified, and characterized by a high-performance liquid chromatography-mass spectrometry technique. Several probable photodegradation pathways were proposed and discussed.

Measurement of angular distributions of Drell-Yan dimuons in p+p interactions at 800 GeV/c

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a hydrogen target. The polar and azimuthal angular distribution parameters have been extracted over the kinematic range 4.5<m micromicro<15 GeV/c2 (excluding the Upsilon resonance region), 0<p T <4 GeV/c, and 0<x F<0.8. The p+p angular distributions are similar to those of p+d, and both data sets are compared with models which attribute the cos2varphi distribution either to the presence of the transverse-momentum-dependent Boer-Mulders structure function h1 perpendicular to 1 or to QCD effects. The data indicate the need to include QCD effects before reliable information on the Boer-Mulders function can be extracted. The validity of the Lam-Tung relation in p+p Drell-Yan data is also tested.

High-power millimeter-wave rotary joint

The rotary joint is a useful microwave component that connects a fixed part to a rotatable part. This study systematically analyzes the effect of the discontinuity on the interface of a rotary joint for several waveguide modes. Simulation results indicate that the transmission of the TE(01) mode is independent of the geometry of the joint, and thus is ideal for such application. A rotary joint consisting of two identical TE(01) mode converters, clasped each other by a bearing, is designed, fabricated, and tested. Back-to-back transmission measurements exhibit an excellent agreement to the results of computer simulations. The measured optimum transmission is 97% with a 3 dB bandwidth of 8.5 GHz, centered at 35.0 GHz. The cold measurement shows that the results are independent of the angle of rotation. In addition, a high-power experiment is conducted. The just developed rotary joint can operate up to a peak input power of 210 W with a duty of 18%. The working principle, although demonstrated in the millimeter-wave region, can be applied up to the terahertz region where the joint gap is generally critical except for the operating TE(01) mode.

Measurement of Upsilon production for p + p and p + d interactions at 800 GeV/c

We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, sigma(p+d-->Upsilon)/2sigma(p+p-->Upsilon), is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0<x(F)<0.6, this ratio is found to be consistent with unity, in striking contrast to the behavior of the Drell-Yan cross section ratio sigma(p+d)(DY)/2sigma(p+p)(DY). This result shows that the gluon distributions in the proton and neutron are very similar. The Upsilon production cross sections are also compared with the p+d and p+Cu cross sections from earlier measurements.

Effect of microwave annealing temperatures on lead zirconate titanate thin films

Lead zirconate titanate (Pb(1.1)(Zr(0.52)Ti(0.48))O(3)) thin films of thickness 260 nm on Pt/Ti/SiO(2)/Si substrates were densified by 2.45 GHz microwave annealing. The PZT thin films were annealed at various annealing temperatures from 400 to 700 °C for 30 min. X-ray diffraction showed that the pyrochlore phase was transformed to the perovskite phase at 450 °C and the film was fully crystallized. The secondary (again pyrochlore) phase was observed in the PZT thin films, which were annealed above 550 °C. The surface morphologies were changed above 550 °C of the PZT thin films due to the secondary phase. Higher dielectric constant (ε(r)) and lower dielectric loss coercive field (E(c)) were achieved for the 450 °C film than for the other annealed films.

Measurement of angular distributions of Drell-Yan dimuons in p+d interactions at 800 GeV/c

We report a measurement of the angular distributions of Drell-Yan dimuons produced using an 800 GeV/c proton beam on a deuterium target. The muon angular distributions in the dilepton rest frame have been measured over the kinematic range 4.5<m{mu mu}<15 GeV/c{2}, 0<p{T}<4 GeV/c, and 0<x{F}<0.8. No significant cos2phi dependence is found in these proton-induced Drell-Yan data, in contrast with the situation for pion-induced Drell-Yan data. The data are compared with expectations from models which attribute the cos2phi distribution to a QCD vacuum effect or to the presence of the transverse-momentum-dependent Boer-Mulders structure function h{1}{perpendicular}. Constraints on the magnitude of the sea-quark h{1}{perpendicular} structure functions are obtained.

Staphylococcus aureus peptidoglycan ameliorates cyclophosphamide-induced impairment of wound healing

Cyclophosphamide given systemically to rats leads to impaired wound healing, characterized by decreases in the inflammatory reaction, fibroplasia, neovascularization, reparative collagen accumulation, and wound breaking strength. In contrast, the local application of Staphylococcus aureus peptidoglycan at the time of wounding increases all of these processes in normal rats. Accordingly, we hypothesized that inoculation of S. aureus peptidoglycan into wounds of cyclophosphamide-treated rats would ameliorate the otherwise impaired healing. Dorsal bilateral skin incisions and subcutaneous implantation of polyvinyl alcohol sponges (two on each side) were performed on male Sprague-Dawley rats receiving either saline or cyclophosphamide (24 mg/kg) intraperitoneally at the time of operation, on postoperative days 1, 2, 3, 4 (for rats killed on postoperative day 7), and also on day 8 (for rats killed on postoperative day 14). The incisions on one side were inoculated at the time of closure with 0.2 ml of saline solution, and the incisions on the other side with 6 mg S. aureus peptidoglycan in 0.2 ml saline solution (860 microg/cm incision). The sponges were instilled with 0.1 ml saline solution on the saline solution-instilled incision side or with S. aureus peptidoglycan 0.5 mg/sponge) in 0.1 ml saline solution on the other side. In control rats receiving saline solution intraperitoneally, incisions treated with S. aureus peptidoglycan were significantly stronger than saline solution-treated incisions by a factor of 1.8 at 1 week (p < 0.001); at 2 weeks the increase was small and not significant. Cardiac blood leukocytes and platelets fell markedly (90%) in cyclophosphamide- treated rats, and there was a decrease in wound breaking strength of their saline-treated incisions at both 7 and 14 days compared with saline solution-treated incisions of control rats. S. aureus peptidoglycan treatment of the wounds completely prevented this effect at 7 days, and partially at 14 days. Polyvinyl alcohol sponge reparative tissue hydroxyproline, 7 days after surgery, was decreased in cyclophosphamide-treated rats; this was completely prevented by S. aureus peptidoglycan treatment of the sponges. Histologically, the inflammatory response to the wounding, influx of macrophages and fibroblasts, angiogenesis, and collagen accumulation were all reduced at day 7 and 14 after surgery in the sponge reparative tissue of cyclophosphamide- treated rats; this was prevented by S. aureus peptidoglycan treatment of the sponges. In conclusion, a single local application of S. aureus peptidoglycan ameliorates cyclophosphamide-impaired wound healing.

Single local instillation of nonviable Staphylococcus aureus or its peptidoglycan ameliorates glucocorticoid-induced impaired wound healing

An excess in glucocorticoid steroids, either from endogenous or exogenous sources, has been shown to inhibit wound repair. Key to this impairment is a diminution of the inflammatory response to wounding, fibroplasia, capillary formation, reparative tissue collagen accumulation, and wound breaking strength. Because a single local application at operation of nonviable Staphylococcus aureus or its peptidoglycan increases all of these processes in normal rats, we hypothesized that nonviable S. aureus and S. aureus peptidoglycan would each ameliorate glucocorticoid-induced impaired healing. Sprague-Dawley male rats aseptically received two 7 cm paravertebral skin incisions and underwent subcutaneous implantation of polyvinyl alcohol sponges. Two glucocorticoids were used: hydrocortisone, 8 mg intramuscularly, daily beginning 1 day before operation and continuing during the postoperative period; or a single dose of a long-acting preparation of methylprednisolone, 6 or 8 mg intramuscularly, on the day before operation. Controls received intramuscular injections of saline solution at the same respective times. At the time of the operation, one incision and the polyvinyl alcohol sponges on one side of the animal were instilled with saline solution while the incision and sponges on the opposite side were instilled with nonviable S. aureus (hydrocortisone study) or S. aureus peptidoglycan (two methylprednisolone studies). The data showed that, at postoperative day 7, the single local application at wounding of nonviable S. aureus or S. aureus peptidoglycan increased wound breaking strength in the control rats by factors of 1.6 in the hydrocortisone experiment and 1.4 and 1.6 in the methylprednisolone studies. These treatments prevented (in hydrocortisone-treated rats) or mitigated (in methylprednisolone-treated rats) the glucocorticoid-induced decrease in wound breaking strength. In addition, these treatments prevented the glucocorticoid-induced decreases in the inflammatory (largely mononuclear cells) response to wounding and in the accumulation within the polyvinyl alcohol sponge of reparative tissue fibroblasts, capillaries, and collagen.

Variation in Bentgrass Susceptibility to Typhula incarnata and in Isolate Aggressiveness Under Controlled Environment Conditions

Typhula incarnata, the causal agent of gray snow mold, is an important winter pathogen of turfgrasses in the northern United States. The relative susceptibility of cultivars of three bent-grass species (creeping, colonial, and velvet bentgrass) to Typhula incarnata and the aggressiveness of 15 T. incarnata isolates obtained from infected turfgrasses on golf courses in Michigan, Minnesota, and Wisconsin were evaluated under controlled conditions. A hypersensitive type of resistance response to T. incarnata was not observed in any cultivar. Disease severity increased with higher inoculum concentration of T. incarnata. Colonization by gray snow mold gradually decreased with increasing plant age from 11 weeks after seeding in most cultivars tested, suggesting that age-related resistance was expressed over time. There were significant differences in disease severity among the three bentgrass species, particularly between tetraploid (creeping and colonial) and diploid (velvet) species, and among cultivars within each species, indicating varying levels of susceptibility to T. incarnata. All 15 isolates were pathogenic on bentgrass and were significantly different in aggressiveness, but aggressiveness was not related to geographic origin. Therefore, turfgrass breeders should be able to use one or a few virulent representative isolates of the pathogen to screen for resistance.

Rise and fall time behavior of the gyrotron backward-wave oscillator

The rise and fall time behavior of a pulsed microwave oscillator is a problem of academic interest. It is also of importance to radar and other applications because it can lead to phase and frequency jitters or even lock the entire pulse into an undesired mode. Here we present a study of the rise and fall time behavior in the gyrotron backward-wave oscillator (gyro-BWO). Single-mode simulations reveal that, during the rise and fall portions of the electron beam pulse, oscillation frequencies of the axial modes vary in such a way that their transit angles remain at the respective optimum values. Thus, axial mode competition and mode switching can readily take place in these transient stages. Time-dependent simulations demonstrate that, under both the gradual and instant turn-on conditions, the axial modes compete in a pattern governed by the characteristic asymmetry of the mode profiles. Other aspects of physics interest include the analysis and explanation of a resultant hysteresis effect between the rise and fall portions of the beam pulse. These understandings are expected to provide the basis for achieving a stable gyro-BWO operating at a single mode throughout the entire beam pulse.

Transition of absolute instability from global to local modes in a gyrotron traveling-wave amplifier

The gyrotron traveling-wave amplifier employing the distributed-loss scheme is capable of very high gain and effective in suppressing the global absolute instabilities. This study systematically characterizes the local absolute instabilities and their transitional behavior. The local absolute instabilities are analyzed using a model that incorporates the penetration of the field from the copper section into the lossy section. The axial modes were characterized from the perspective of beam-wave interaction and were found to share many characteristics with the global modes. The transition from global modes to local modes as the distributed loss increases was demonstrated. The electron transit angle in the copper section, which determines the feedback criterion, governs the survivability of an oscillation. In addition, the oscillation thresholds predicted using this model are more accurate than those obtained using a simplified model.

Aggressiveness of Typhula ishikariensis Isolates to Cultivars of Bentgrass Species (Agrostis spp.) Under Controlled Environment Conditions

Speckled snow mold, caused by Typhula ishikariensis, is one of the most important Typhula snow molds in subarctic zones of the Northern Hemisphere. Nine isolates of three T. ishikariensis varieties (var. ishikariensis, var. canadensis, and var. idahoensis) isolated from infected turfgrasses on golf course fairways throughout Wisconsin were evaluated for their aggressiveness toward nine cultivars of three bentgrass species (three creeping, three colonial, and three velvet cultivars) under controlled environmental conditions. Speckled snow mold severity increased as inoculum concentration of T. ishikariensis was increased. In general, bentgrass susceptibility increased between 9 and 11 weeks after seeding but gradually decreased thereafter, suggesting expression of age-related resistance as plants matured. Significant differences in aggressiveness were detected within and among T. ishikariensis varieties. Significant interactions between T. ishikariensis varieties or isolates and bentgrass species were detected, but there was no interaction between pathogen isolates and bentgrass cultivars. Disease severity evaluations showed significant differences among bentgrass cultivars and species in their response to T. ishikariensis. Since bentgrass species exhibit differential responses to T. ishikariensis varieties, representative isolates of each variety should be employed for screening of bentgrass germplasm for resistance to speckled snow mold.

Dynamics of mode competition in the gyrotron backward-wave oscillator

The axial modes of the gyrotron backward-wave oscillator (gyro-BWO) each exhibit a distinctive asymmetry in axial field profile. As a result, and in sharp contrast to the behavior of the familiar resonator-based gyrotron oscillator, particle simulations of the gyro-BWO reveal a radically different pattern of mode competition in which a fast-growing and well-established mode is subsequently suppressed by a later-starting mode with a more favorable field profile. This is verified in a Ka-band experiment and the interaction dynamics are elucidated with a time-frequency analysis.

Absolute instabilities in a high-order-mode gyrotron traveling-wave amplifier

The absolute instability is a subject of considerable physics interest as well as a major source of self-oscillations in the gyrotron traveling-wave amplifier (gyro-TWT). We present a theoretical study of the absolute instabilities in a TE01 mode, fundamental cyclotron harmonic gyro-TWT with distributed wall losses. In this high-order-mode circuit, absolute instabilities arise in a variety of ways, including overdrive of the operating mode, fundamental cyclotron harmonic interactions with lower-order modes, and second cyclotron harmonic interaction with a higher-order mode. The distributed losses, on the other hand, provide an effective means for their stabilization. The combined configuration thus allows a rich display of absolute instability behavior together with the demonstration of its control. We begin with a study of the field profiles of absolute instabilities, which exhibit a range of characteristics depending in large measure upon the sign and magnitude of the synchronous value of the propagation constant. These profiles in turn explain the sensitivity of oscillation thresholds to the beam and circuit parameters. A general recipe for oscillation stabilization has resulted from these studies and its significance to the current TE01 -mode, 94-GHz gyro-TWT experiment at UC Davis is discussed.

J/psi polarization in 800-GeV p-Cu interactions

We present measurements of the polarization of the J/psi produced in 800-GeV proton interactions with a copper target. Polarization of the J/psi is sensitive to the ccmacr; production and hadronization processes. A longitudinal polarization is observed at large x(F), while at small x(F) the state is produced essentially unpolarized or slightly transversely polarized. No significant variation of the polarization is observed versus p(T).