Search

It is well known that freshly created ions can be picked up by a moving plasma via self-consistently excited Alfven waves, as discovered in cometary physics in the late 1980s. This paper discusses the ion pickup process in a regime very different from what has been investigated before. We show that such a process can occur inside a magnetic reconnection layer. We suggest that this process might explain the origin of solar energetic ions associated with flares. In order to demonstrate that the acceleration process is rapid and efficient, a series of numerical simulations are carried out for the parameter regime relevant to solar active regions in the lower corona. Simulation results show that not only can the newly created ions that result from ionization of neutral atoms be accelerated, but the background thermal ions can be intensely heated as well when they interact with the excited Alfven waves.

Freshly created ions can be picked up by a moving plasma without relying on collisions. It is well known that such an ion pickup process can be accomplished via the interaction with Alfven waves. However, it should be stressed that in general ion pickup is attributed to two distinctly different sub-processes, namely, pitch-angle diffusion and pitch-angle scattering. In this article their difference is discussed and furthermore, some new results from a recent theoretical study are reported. It is found that under some conditions the usual quasilinear theory which describes the pitch-angle diffusion process cannot be justified even when the turbulence level is low. Another significant finding is that in the presence of strong Alfven turbulence, thermal ions can be intensely heated by a nonlinear damping of the waves, which does not depend upon the usual ion cyclotron resonance.

In this paper we discuss the dynamics of an ion interacting with large-amplitude Alfven waves. The objective of the present analysis is to attain an in-depth understanding of the ion-pickup process which has been extensively studied in the literature by means of both quasilinear theory and numerical simulations. In general, results from self-consistent simulations provide a more complete picture of the ion pickup process, but details of the pickup process are not easily comprehended on the basis of these results. For this reason, the present study is carried out in which a test particle approach is used. It is found that for moderately large-amplitude Alfven waves, an approximate analytical solution for the ion equation of motion can be obtained. This solution clarifies a number of basic issues such as (1) whether the cyclotron resonance is a necessary condition for the pickup to occur, (2) what is the role of initial ion phase space position on subsequent pitch angle scattering, and (3) how the wave amplitude affects the maximum velocity that an ion can gain along the direction of the ambient magnetic field during the pickup process.

A cyclotron maser mechanism for the auroral kilometric radiation (AKR) proposed by Wu and Lee (1979) and Lee et al. (1980) is reviewed with a discussion of recent developments concerning the quasilinear saturation of AKR and its energy conversion. Emphasis is on the case in which the population of the secondary electrons prevails over that of the energetic electrons. The limit of zero secondary electrons is examined, and it is found that the dispersion relation of the radiation is significantly modified.

Ion pickup by the solar wind is a topic of current interest. In situ observations and theoretical studies establish a fairly good understanding of the physics of the ion-pickup process. In a weakly turbulent solar wind, hydromagnetic waves that are either intrinsic or excited by the newborn ions can lead to pitch-angle diffusion which can be approximately described by the quasi-linear theory with or without incorporating the resonance-broadening mechanism due to weak turbulence. According to the weak turbulence theory, the pickup ions do not form a complete spherical shell distribution in the time-asymptotic state unless the wave field is sufficiently strong. In some cases the ions only possess a partial or incomplete shell. When the solar wind is highly turbulent, direct interaction between the wave fields and the newborn ions can result in rapid pitch-angle scattering leading to swift formation of a spherical shell distribution on the time scale of an ion gyro-period.

An acceleration process which may occur in solar active regions is proposed to explain the origin of energetic particles associated with solar flares. The scenario suggested may be described as follows: first, newborn ions, protons, as well as minor heavy ion species, produced continuously in the upper chromosphere through the lower corona can excite Alfven waves near a reconnection region. We suggest that the build up of Alfvenic turbulence in that region can lead to rapid acceleration of newborn protons created later to energies as high as several 10e100 MeV via a pickup process. Proton acceleration takes place mainly inside the reconnection layer. However, the enhanced Alfven waves can also energize minor heavy ions outside or away from the reconnection layer. The present model suggests that ascending as well as descending energetic ions can be produced at the same time, as implied by observations. Furthermore, since energetic ions can "carry" electrons with them due to charge and current neutrality conditions, the model also explains solar energetic electrons of the order of 10e100 keV as well.

Almost all plants have the experience of ACB's overcurrent relay (OCR) unexpectedly trip event. Each accident will cause a huge production loss. But manufacturers of OCR can't afford the cost-effective solution of problem. The most used solution is to install an additional relay (ex. ABB Relay B) to replace the function of the ACB's OCR or to adopt a new ACB to replace the old one. These two uneconomical solutions are not only high cost but also time consumption on annual PM. Thus, authors proposed a novel solution by interlocking the main ACB's relay and the feeder ACB's OCR function to prevent the ACB tripped by OCR false tripping signal. This method does not require additional relay and current transformer. Therefore, it is a cost-effective and time saving solution.

The problem of a plane shock wave that propagates in an air media and then is reflected from a parabolic concave reflector and focuses at some region is considered. The shock focusing can greatly magnify the pressure and the temperature. The purpose of this study is to numerically simulate the shock focusing process of the reflection of shock waves from the parabolic reflectors with different depths and to analyze their associated flow fields in detail. The present solver developed is to solve the Euler equations using an improved, implicit, upwind Total Variation Diminishing scheme in a finite-volume approach. The effects of reflectors with different depths and of the incident shock Mach numbers on shock focusing are investigated. The real-gas effect is taken into account through a proper correction of the specific heat ratio of air, when high temperature occurs due to shock focusing.

Identification of Alfven waves in the solar wind by means of spacecraft measurements was first achieved in late 1960s. Subsequent study of these waves has found that Alfven waves in interplanetary space is a very complicated topic. Two and half decades after the first discovery there are still many issues unresolved. The only agreement reached by scientists is that the predominant component of the Alfven waves observed in the solar wind is of solar origin. What is the generation mechanism and how these waves evolve in interplanetary space are still unclear. But on the other hand there exists another family of Alfven waves which are not of solar origin. The best example is those waves generated in the exosphere of a comet. For these waves the physics is much better understood. In the present paper we discuss the two families of Alfven waves separately.

Although chronic rhinosinusitis without nasal polyps (CRSsNP) and psoriasis both share immunological disturbances as pathological factors, no prior study has investigated the risk for psoriasis among patients with CRSsNP.To investigate the subsequent risk for psoriasis following a diagnosis of CRSsNP by utilizing a cohort study design and a population-based dataset in Taiwan.In total, 13 242 subjects with CRSsNP were included in the study cohort and 39 726 subjects were randomly extracted for the comparison cohort. We individually tracked each individual in this study (n = 52 968) for a 5-year period following their index date to identify those subjects who received a subsequent diagnosis of psoriasis. Cox proportional hazards regression analysis was conducted to calculate the 5-year risk of subsequent psoriasis following a diagnosis of CRS among the sampled subjects.The incidence rate of psoriasis during the 5-year follow-up period was 1·41 [95% confidence interval (CI) 1·14-1·71] per 1000 person-years and 0·69 (95% CI 0·59-0·81) per 1000 person-years for the study and comparison cohort, respectively. Stratified Cox proportional hazards regression revealed that the hazard ratio for psoriasis during the 5-year follow-up period for subjects with CRSsNP compared with the control group was 2·01 (95% CI 1·54-2·62) after adjusting for monthly income, geographical region, hypertension, diabetes, coronary heart disease and hyperlipidaemia, and censoring the cases who died during the 5-year follow-up period.This study detected an increased risk for psoriasis among patients with CRSsNP.

Psoriasis is a systemic disease associated with metabolic disorders and vascular complications. Both psoriasis and metabolic disorders are associated with systemic inflammation. We hypothesized that the sequence of events between the onset of psoriasis and metabolic disorder may affect the risk for subsequent development of vascular complications.Nested case-control study was performed using the Taiwan National Health Insurance database. Accordingly, a total of 8180 psoriatic patients and 163,600 controls were included. Psoriasis was considered as the initiator of inflammatory march if metabolic disorder, including hypertension, diabetes mellitus and dyslipidemia, developed after onset of psoriasis. In patients with pre-existing metabolic disorder, psoriasis was considered as the amplifier of inflammatory march.In patients whose psoriasis served as the disease initiator, a lower risk for developing vascular disease (HR = 1.49; 95% CI = 1.11-2.00 and HR = 1.64; 95% CI = 1.31-2.05 for cerebrovascular and cardiovascular events, respectively) was found compared with patients whose psoriasis served as the disease amplifier (HR = 2.26; 95% CI = 1.72-2.97 and HR = 2.78; 95% CI = 2.26-3.42 for cerebrovascular and cardiovascular events, respectively) after adjusting for age and gender. In terms of treatment implications, methotrexate was associated with reduced risk for developing cerebrovascular event (HR = 0.22; 95% CI = 0.05-0.88) only in patients with psoriasis serving as the disease amplifier.Our results suggested that two scenarios of systemic inflammatory marches are present among psoriatic patients with metabolic disorder and judicious use of methotrexate may reduce the risk of cerebrovascular event, especially when psoriasis served as the disease amplifier of the systemic inflammatory march.

Keloid is a unique proliferative disorder of fibroblasts resulting from derailment of the typical wound healing process. Due to lack of animal models for therapeutic testing, treatment of keloids remains a clinical challenge. Transforming growth factor (TGF)-β1-related signalling plays a key role in keloid formation. As tacrolimus (FK506) has been reported to inhibit the effects of TGF-β1 on cultured fibroblasts, we hypothesized that FK506 may be useful in treating keloids.To explore the effects of FK506 on TGF-β1-stimulated keloid fibroblasts (KFs) in terms of proliferation, migration and collagen production and to investigate the regulatory pathways involved.Fibroblasts derived from keloids were treated with TGF-β1 with or without FK506. Relevant assays including 5-bromo-2'-deoxyuridine incorporation assay, in vitro scratch assay, reverse transcription-polymerase chain reaction (PCR), quantitative PCR and Western blotting were performed.The proliferation and migration of KFs were significantly higher than those of normal fibroblasts. FK506 markedly inhibited KF proliferation, migration and collagen production enhanced by TGF-β1. The increase in TGF-β receptor I and II expression in TGF-β1-treated KFs was suppressed by FK506 treatment. TGF-β1 increased the phosphorylation of Smad2/3 and Smad4 in KFs, and this enhancing effect was abrogated by FK506. In addition, FK506 significantly increased the expression of Smad7 which was suppressed by TGF-β1 treatment.Our results demonstrate that FK506 effectively blocks the TGF-β/Smad signalling pathway in KFs by downregulation of TGF-β receptors and suggest that FK506 may be included in the armamentarium for treating keloids.

In this article, a new emission process for radiation near the plasma frequency in an unmagnetized plasma (i.e., the plasma emission) is discussed. The process involves a tenuous beam of energetic electrons and low‐frequency ion waves. The key point is that the ion waves can modulate the thermal electron density so that the condition for beam–plasma interaction (ω=k⋅V, where V is the average beam velocity) is Doppler shifted in wave vector space in accordance with the wavelength that characterizes the ion density fluctuations [ω+ω’=(k+k’)⋅V, where ω’ and k’ are the characteristic frequency and wave vector associated with the ion wave; in the present discussion, let set ω’=0]. As a result, the unstable electrostatic beam–plasma mode becomes coupled with the fast electromagnetic mode. Consequently in an inhomogeneous plasma the amplified waves can naturally change to electromagnetic mode and escape from the source region.

When designing the structure of an artificial neural network (ANN), it is very important to determine the architecture and parameters of the network such as number of units and layers. This paper uses the Taguchi method and Design of Experiment (DOE) methodology to optimize the network parameters. The users have to identify the application problems and choose a suitable ANN model. Then, the optimization problems including the design variables, cost function and constraints can be defined according to the network model. The Taguchi method is first applied to the problem for finding the more important factors. Then DOE methodology is performed for further analysis and forecast. Finally, the Multilayer Feed-forward Neural Network is used for an example.

[1] The present paper addresses the stochastic heating of minor ions by obliquely‐propagating low‐frequency Alfven waves in the solar wind. An important characteristics of the stochastic heating is unearthed by means of test particle simulation. That is, when the wave amplitude exceeds some threshold condition for stochasticity, the time‐asymptotic kinetic temperature associated with the minor ions becomes independent of the wave amplitude, and it always approaches the value dictated by the Alfven speed, to wit, Tkin. ∼ mivA /2. During the course of the heating process the minor ions gaina net average parallel speed, vk ∼ vA in the laboratory frame. These results are consistent with observations which find that minor heavy ions often move faster than the local protons with a speed roughly equal to the local Alfven speed. Citation: Wang, B., C. B. Wang, P. H. Yoon, and C. S. Wu (2011), Stochastic heating and acceleration of minor ions by Alfven waves, Geophys. Res. Lett., 38, L10103, doi:10.1029/ 2011GL047729.

Summary Background Topical tacrolimus (FK506) has been considered as a treatment option for treating vitiligo, a dermatosis characterized by disappearance of melanocytes (MCs). Previous reports have shown that a significant portion of treated patients demonstrated follicular repigmentation, indicating that the activation of MC precursor cells residing in the outer root sheath of hair follicles played an important role during the tacrolimus-induced repigmentation process. Objectives To investigate the mechanisms involved in follicular pigmentation induced by topical tacrolimus. Methods As stem cells of MC lineage are identified in the lower portion of mouse hair follicles throughout the hair cycle, immature mouse melanoblasts (MBs) derived from neural crest cells (NCCmelb4) were used for this study. Relevant maturation parameters were evaluated. Results Our results revealed that FK506 stimulated the expressions of protein kinase A, protein kinase C and phosphorylated p38 mitogen-activated protein kinase. However, cell motility, a parameter associated with MB differentiation, was not enhanced by FK506 treatment. Endothelin (ET)-3, a prodifferentiation factor of MBs, also failed to promote NCCmelb4 cell locomotion. Combining ET-3 and FK506, however, stimulated cell mobility. ET B receptor, which was not present in NCCmelb4 cells, was induced after FK506 treatment. Conclusions In summary, we have shown that FK506 is an efficient differentiation-stimulating agent, especially for cells of neural origin. The clinical efficacy of topical tacrolimus on vitiligo may be enhanced by combination with ET-3.

In this paper, rate type constitutive equations using the Jaumann and 2nd Piola-Kirchhoff stress rate are used to develop axisymmetric finite strain, elastic, closed form solutions for a variety of loading conditions. We examined several cases comprizing compression-extension loading conditions, simple shear and cavity expansion conditions. Results from small strain analyses are used to indicate strain ranges for which such analyses will provide satisfactory solutions. For all the cases examined, except simple shear, the 2nd Piola-Kirchhoff stress rate does not appear to be a suitable stress rate to describe a material which follows a rate-type constitutive equation for strains greater than about 40%. The Jaumann stress rate solution shows oscillatory shear stress for axisymmetric simple shear similar to that found earlier by many other authors for rectangular (or cuboidal) condition. Negative excess pore water pressure (suction) at the cavity wall during the expansion of a cylindrical cavity was also observed in Jaumann stress rate solution.

Gas separations using commercial ceramic membranes with 40 A pore diameter were performed for three binary mixtures: H2/CO, H2/N2 and He/O2. The experimental conditions covered a wide range of temperatures (25 to 815°C) and pressures (3 to 38 atm). A mathematical model based upon Knudsen diffusion and intermolecular momentum transfer was developed to predict gas separation efficiency. The experimental results agreed well with the model prediction. The permeability of CO was substantially lower than the value expected from Knudsen diffusion. Nevertheless, the model developed was able to account for this phenomenon and predicted equally well for a binary mixture containing CO. The effect of key operating parameters on separation behavior was studied with the model developed.

Visible light is a treatment option for segmental vitiligo (SV), and visible light-induced repigmentation is associated with normalization of sympathetic dysfunction. Currently, it is difficult to predict individual patients' response to visible light therapy.To test whether cutaneous blood flow can serve as a response predictor for visible light on treating SV.Fourteen patients with SV were recruited in this prospective pilot study. Laser Doppler flowmetry was used to evaluate the cutaneous blood flow over SV lesions and contralateral normal skin. The pretreatment blood flow evaluation consisted of two stages: stage 1, following cold stress without prior visible light irradiation, and stage 2, following cold stress with prior visible light irradiation. Subsequently, the patients received regular visible light treatment for 3months, and a comparison of the pretreatment blood flow patterns between the visible light responding and nonresponding groups was carried out at the end of the study period.The SV lesions showed different blood flow profiles as compared with the contralateral normal skin. At the end of the 3-month study period, seven (50%) patients showed clinical repigmentation of25%. The visible light responding group showed a more consistent occurrence of increased blood flow after stage 2 of the pretreatment evaluation while the nonresponding counterpart showed no significant changes.Normalization of sympathetic dysfunction may account for the efficacy of visible light in treating SV. Evaluation of cutaneous blood flow with and without prior visible light irradiation on cold-stressed SV lesions may serve as a treatment response predictor.

Topical tacrolimus (FK506) has been considered as a treatment option for treating vitiligo, a dermatosis characterized by disappearance of melanocytes (MCs). Previous reports have shown that a significant portion of treated patients demonstrated follicular repigmentation, indicating that the activation of MC precursor cells residing in the outer root sheath of hair follicles played an important role during the tacrolimus-induced repigmentation process.To investigate the mechanisms involved in follicular pigmentation induced by topical tacrolimus.As stem cells of MC lineage are identified in the lower portion of mouse hair follicles throughout the hair cycle, immature mouse melanoblasts (MBs) derived from neural crest cells (NCCmelb4) were used for this study. Relevant maturation parameters were evaluated.Our results revealed that FK506 stimulated the expressions of protein kinase A, protein kinase C and phosphorylated p38 mitogen-activated protein kinase. However, cell motility, a parameter associated with MB differentiation, was not enhanced by FK506 treatment. Endothelin (ET)-3, a prodifferentiation factor of MBs, also failed to promote NCCmelb4 cell locomotion. Combining ET-3 and FK506, however, stimulated cell mobility. ET B receptor, which was not present in NCCmelb4 cells, was induced after FK506 treatment.In summary, we have shown that FK506 is an efficient differentiation-stimulating agent, especially for cells of neural origin. The clinical efficacy of topical tacrolimus on vitiligo may be enhanced by combination with ET-3.

[1] To evaluate the response of river discharge to anthropogenic impacts and climate variability over the Industrial Period, we reconstructed past series of monthly discharge from three gauges on the main river of the Yangtze by means of regression (making use of the cross correlation among the gauges) and analyzed the integrated data (the observed series of discharge with missing values filled by reconstructed values) for the period 1865–2008 in relation to human activities and climate variability. The correlative coefficients between observed and predicted discharges at the three stations for the gauging period are R2 = 0.90–0.96 (n = 827–1557). The integrated time series of discharge to the sea shows periodicities of ∼7, ∼14, and ∼38 years, and we found significant decreasing trends in annual discharge (−11%) and monthly discharge from August to November (−47% for November) and an increasing trend in discharge in January (+30%) and February during the dry season. These trends are mainly attributed to human impacts, in particular, reservoir construction and water consumption. It is estimated that these trends will continue in the future decades of this century because of the influence of the South-to-North Water Diversion Project as well as increased water consumption and the construction of new dams within the river basin.

To date, North Sea tidal flat sediments have been intensively studied down to a depth of 5 m below sea floor (mbsf). However, little is known about the biogeochemistry, microbial abundance, and activity of sulfate reducers as well of methanogens in deeper layers. For this study, we hypothesized that the imprint of the paleo-environment is reflected in current microbiogeochemical processes. Therefore, 20 m-long cores were retrieved from the tidal-flat area of Spiekeroog Island, NW Germany. Two drill sites were selected with a close distance of only 900 meters, but where sedimentation occurred under different environmental conditions: first, a paleo-channel filled with Holocene sediments and second, a mainly Pleistocene sedimentary succession. In general, the numbers of bacterial 16S rRNA genes are one to two orders of magnitude higher than those of Archaea. The abundances of key genes for sulfate reduction and methanogenesis (dsrA and mcrA) correspond to the sulfate and methane profiles. A co-variance of these key genes at sulfate-methane interfaces and enhanced potential AOM rates suggest that anaerobic oxidation of methane may occur in these layers. Microbial and biogeochemical profiles are vertically stretched relative to 5 m-deep cores from shallower sediments in the same study area. Compared to the deep marine environment, the profiles are transitional between the shallow subsurface and the marine deep biosphere. Our interdisciplinary analysis shows that the microbial abundances and metabolic rates are elevated in the Holocene compared to Pleistocene sediments. However, this is mainly due to present environmental conditions such as pore water flow and organic matter availability. The paleo-environmental imprint is still visible but superimposed by these processes.

The present paper shows that the reflected ion at a supercritical quasiperpendicular shock wave can excite a purely growing m9de propagating parallel to the ambient magnetic field (k∥B0). To discuss the ion heating by such an unstable mode, the self‐consistent quasilinear kinetic equation is solved with the assumption that the present purely growing mode is the dominant unstable mode in the system. In the quasilinear analysis of the instability, two particular cases are considered—the case of low initial ion beta [βi(0)=0.1] and that of a high initial ion beta [βi(0)=1]. For each case of low and high initial betas, two values of initial turbulence level are used. One corresponds to δB2(0)/B20=0.1 and the other corresponding to δB2(0)/B20 =0.1. It is shown that for both low and high beta cases, the ion heating at the shock becomes more efficient for a higher value of δB2(0)/B20.

The effects of high pressure, high temperature and high shear rate on the viscosity of VI improved oils are simulated in a series of high-shear experiments by either lowering the experimental temperature or increasing the molecular weight of the base oil. This study clearly demonstrates that there is no significant difference between the two methods for simulating the high temperature and high pressure conditions. Presented as a Society of Tribologists and Lubrication Engineers paper at the STLE/ASME Tribology Conference in St. Louis, Missouri, October 14–16, 1991

Circular dichroism (CD) and Fourier transform infrared spectroscopic studies have shown that the secondary structure of transforming growth factor alpha (TGF-alpha) is very similar to that of epidermal growth factor (EGF). The infrared spectra revealed a minor difference between the two proteins, in particular in the beta-sheet structure. A large difference was observed with CD between the two proteins in the apparent conformation each adopts when the disulfide bonds are reduced. Reduced TGF-alpha showed a distinct alpha-helical conformation only at a high trifluoroethanol concentration, whereas reduced EGF assumed an alpha-helical conformation in the absence of trifluoroethanol. This indicates that these two proteins adopt different secondary structures in the absence of disulfide bonds, although they assume similar folding structures in their presence. These data suggest that the disulfide bonds to a large degree dictate the conformation of these two proteins. Additionally, differences in the dynamic behavior between EGF and TGF-alpha were also observed. Infrared experiments showed that the hydrogen-deuterium exchange rate is much higher for TGF-alpha than for EGF, indicating that TGF-alpha is a more flexible molecule. The rate of reduction of the disulfide bonds by dithiothreitol was also faster for TGF-alpha. Therefore, it can be concluded that although EGF and TGF-alpha have a similar overall conformation, TGF-alpha is a more flexible molecule than EGF.

Damage-free, dry-etched 0.25- mu m T-shape gate pseudomorphic InGaAs channel HEMTs have been demonstrated. A Freon-12-based discharge was used in either electron cyclotron resonance (ECR) or reactive ion etching (RIE) systems to perform the gate recess process. Etching selectivity of more than 200 was obtained between the GaAs cap layer and the underlying AlGaAs donor layer. Self-bias voltages of -30 to -50 V were used in the etching process to minimize the damage. Pre- and post-etch clean steps were utilized to achieve uniform etch and removal of any dry-etch-related residues. Schottky diodes fabricated on n-GaAs subjected to either dry or wet etching showed no differences of barrier height, zero-bias depletion depth, and ideality factor. By using the dry etch for gate recess, very tight threshold voltage uniformity was obtained. The devices showed I-V characteristics comparable to that of devices fabricated with a wet chemical process. >

3D-FDTD is used to compute the electromagnetic response of various plasmonic nanostructures. Results of computation and simulation are used to design the contact area of the photo-catalytic reactors. Novel nano-fabrication techniques are developed to implement large surface area of plasmonic nanostructures for photo-catalytic reactors. Measurement and analysis of the photo-catalytic process happened in the newly designed photo-chemical reactors clearly demonstrate better efficiency of some photo-catalytic chemical process such as the decomposition of the Methyl Orange to carbon dioxide and water.

Summary Background The treatment of vitiligo remains a challenge for clinical dermatologists. We have previously shown that the helium–neon laser (He–Ne laser, 632·8 nm) is a therapeutic option for treatment of this depigmentary disorder. Objectives Addressing the intricate interactions between melanocytes, the most important cellular component in the repigmentation scheme of vitiligo, and their innate extracellular matrix collagen type IV, the current study aimed to elucidate the effects of the He–Ne laser on melanocytes. Methods Cultured melanocytes were irradiated with the He–Ne laser. Relevant biological parameters including cell attachment, locomotion and growth were evaluated. In addition, the potentially involved molecular pathways were also determined. Results Our results show that in addition to suppressing mobility but increasing attachment to type IV collagen, the He–Ne laser stimulates melanocyte proliferation through enhanced α2β1 integrin expression. The expression of phosphorylated cyclic-AMP response element binding protein (CREB), an important regulator of melanocyte growth, was also upregulated by He–Ne laser treatment. Using a specific mitochondrial uncoupling agent [carbonyl cyanide m-chlorophenyl-hydrazone (CCCP)], the proliferative effect of the He–Ne laser on melanocytes was abolished and suppression of melanocyte growth was noted. Conclusions In summary, we have demonstrated that the He–Ne laser imparts a growth stimulatory effect on functional melanocytes via mitochondria-related pathways and proposed that other minor pathways including DNA damage may also be inflicted by laser treatment on irradiated cells. More importantly, we have completed the repigmentation scheme of vitiligo brought about by He–Ne laser light in vitro and provided a solid theoretical basis regarding how the He–Ne laser induces recovery of vitiligo in vivo.

Based upon recent and old medical literature, with the exception of high surgical risk symptomatic patients, there remains much debate on how to manage extracranial carotid arterial disease, whether by surgical or endovascular intervention or by medical therapy alone. A review of the various global current carotid artery stent and endarterectomy registries and trials was performed incorporating more than 14,000 patients who have received carotid stents. There is substantial evidence supporting the benefit of carotid artery stenting (CAS) for the high anatomic risk population. Complication rates with symptomatic patients, including octogenarians, continue to show trend towards improvement as operators gain experience. The results are limited for standard risk carotid stenting for symptomatic patients though results with recent trials are pending but will probably show equivalence with endarterectomy. The asymptomatic patient population remains controversial: there is a small but reproducible benefit for revascularization. Long term (1-3 years) neurological results are now being reported for the major registries and trials. Analysis of target lesion revascularization, stroke and death rates of carotid stenting is comparable or better than rates for endarterectomy. Carotid artery stent placement has met the CMS targets 3% for MAE for asymptomatic patients and 6% for symptomatic patients with numerous registries and trials. CAS has also proven outcomes at 3 years with restenosis rates and stroke-free rates comparable or better than CEA. CAS provides an option for patients not suited for medical therapy and who were high-risk for CEA, especially for those symptomatic patients. It is still controversial with the role of stenting asymptomatic patients as well as for octogenarians. However, forthcoming trials will be helpful in providing more insight. Despite questionable studies and bad press, carotid stenting in the right hands with good patient selection is an excellent procedure. Finally, it is important to remember, carotid stenting is still in its early development and will only get better.

Semiempirical SCFMO computations of the MNDO and AM1 varieties have been employed to model possible interaction processes for cocaine with the biological substrate glycine. It was found for the gas-phase species that the most likely interactions occurred as nucleophilic attack of the nitrogen lone pair of glycine on the two carbonyl groups of cocaine. These reactions led to intermediates which further decomposed exothermically to amide and alcohol species. The activation enthalpies for the gas-phase reactions were predicted to be high (39–46 kcal/mol), but it is believed that such processes could possibly occur by reaction pathways with considerably lower activation energies in the liquid state in the presence of mucus containing olfactory binding protein in vertebrate olfactory reception.

The dispersion relation for the low‐frequency electromagnetic waves propagating parallel to the ambient magnetic field is studied for a plasma comprised of energetic ring‐beam distribution of ions and a background population. Detailed properties of the dispersion relation are studied for various physical parameters with particular emphasis placed on the transition from the cold case to the thermal regime. In addition, the stability characteristics are investigated for different values of α, where tan α is the ratio between the ring and the beam velocity, ranging from α=0 (pure beam) to α=90° (pure ring). The unstable modes are studied in further detail, and the dependence of the growth rate on several parameters, such as the density of the ring‐beam ions and thermal speeds associated with the background and the ring‐beam ions, is discussed.

A theory of generation of radio waves observed by ground-based facilities in the frequency range 150-700 kHz is discussed. This work is a continuation of an earlier discussion (Wu et al., 1989) in which it was proposed that the trapped electrons along the auroral field lines can lead to a cyclotron instability which amplifies the whistler waves observed at ground level. The objective of the present study is to investigate the propagation effect on the wave amplification and to examine whether the proposed mechanism is indeed viable.

The composition and location of gallstones differ in Western and Eastern people. This has been documented in the literature. The difference in the clinical manifestations of biliary calculous disease has been postulated to be based on ethnic or environmental factors. In an effort to improve our management of patients with gallbladder perforations, a combined hospital study in a Chinese population during 11 years was conducted to study the clinical profiles at risk. Seventy-one patients were studied. The perforations were categorized as either acute (type I) in 14 (19.7%), subacute (type II) in 25 (35.2%), or chronic (type III) in 32 (45.1%). The incidence of severe underlying disease was significantly greater (p = 0.02) in patients with acute and subacute perforation as compared with chronic perforation. Multiple stones in the biliary tree and the gallbladder are very common and may mask the presentation of gallbladder perforation when patients with either biliary colic or biliary tract infection. A history suggestive of chronic gallstone disease is common, especially in patients with chronic perforation. The clinical manifestations of gallbladder perforation are similar to those of acute cholecystitis without perforation. On the basis of these data, clinical profiles have been developed for patients at risk of developing acute versus chronic gallbladder perforation. Awareness of these groupings forms the basis for early recognition and treatment of acute gallbladder perforation.

We study the cyclotron maser instability (CMI) driven by an energetic ring-beam distribution by a particle simulation to explain possible generation mechanisms of intense radiation phenomena observed in space. The main objective is to understand the nonlinear processes that control saturation of the emission process. Our study reveals new issues that have been overlooked in past literature. It is found that electrostatic wave modes excited by the electron beam instability compete with the electromagnetic waves excited by the CMI. Nonlinear effects of these electrostatic modes tend to redistribute the energy of the energetic electrons and make the physics more complicated. The CMI can be much less effective in a realistic case than it is anticipated theoretically.

Background Cutaneous metastases are perceived as a sign of advanced disease and are regarded as a grave prognostic indicator. In addition, few reports have focused on the cutaneous metastasis profiles of Asian patients. Objectives We seek to analyse the clinical and prognostic characteristics of cutaneous tumour metastases in a Taiwanese medical centre. Methods Clinical records from Kaohsiung Medical University Hospital over the last 20 years (1986–2006) were reviewed, and cases of biopsy-proven cutaneous metastases from internal malignancies identified. Survival rates were evaluated using the Kaplan-Meier method and compared by the log-rank test. The Cox proportional hazards model was used for univariate analysis to determine the risk of mortality among different groups. Results A total of 141 cases of cutaneous metastases were identified. The clinical profiles were similar to those from western countries, although the frequencies of primary tumours were different. The duration of survival was usually short following diagnosis of cutaneous metastases, but prognosis is significantly better in breast cancer patients with metastases. Moreover, the survival was even longer for breast cancer patients when the metastasis was confined to the skin. Conclusions The risk of skin metastases depends largely on the characteristics of tumour cells, which is similar among different ethnic groups. In terms of prognosis, a subset of breast cancer patients has superior prognosis, even among breast cancer patients with stage IV disease. Physicians should consider this finding in clinical situations to avoid possible misinformation about the prognosis of the disease.

Background Although eccrine poroma (EP) occurs preferentially in palmoplantar areas, pigmented variants of EP have not been documented on the palms and soles. Objectives We seek to confirm the notion regarding lack of pigmented EP on palmoplantar areas and determine whether the absence of pigmentation in palmoplantar EPs is due to lack of expression of melanocyte-stimulating cytokines by tumour cells. Methods We searched the PubMed and Web of Science databases (1966–2006) for reports of pigmented EPs. In addition, a total of 17 EPs were collected from our pathology department. The presence of melanin was examined with haematoxylin-eosin sections, and melanocyte colonization was shown by immunohistochemical stains for tyrosinase. In addition, immunohistochemical staining with antibodies to melanocyte-stimulating cytokines, including endothelin-1, stem cell factor, and nerve growth factor, was done on these tumours. Results A review of the literature revealed 15 pigmented EP reports, none of which were located in palmoplantar areas. Among 17 EPs collected from our pathology department, 7 occurred in palmoplantar areas and 10 in non-palmoplantar areas. Three of the palmoplantar EPs and three of the non-palmoplantar EPs showed positive staining with melanocyte-stimulating cytokines. However, none of the palmoplantar EPs contained melanocytes or melanin pigment, wheras the three non-palmoplantar EPs that stained positively with melanocyte-stimulating cytokines were colonized with melanocytes and showed pigmentation clinically. Conclusions The expression of melanocyte-stimulating factors by tumour cells is associated with melanocyte colonization in non-palmoplantar EPs but not palmoplantar EPs. Therefore, the presence of melanocyte-stimulating cytokines per se is not sufficient by itself to induce melanocyte colonization. Certain characteristics of palmoplantar skin, such as the dermal components of these anatomical sites, may play a role in inhibiting melanocyte colonization of EPs.

Background Behcet's disease (BD) is a recurrent multisystem disease of uncertain aetiology. The young adults are most often affected, usually during the third decade. Late occurrence of the disease is considered uncommon and less frequently investigated. Objective The aim of this study was to examine the clinical features of BD patients with disease onset at a later age and compare them with the usual age of onset group. Methods Retrospective review of clinical charts of BD patients was conducted. Patients with age of onset at or after 40 years of age were identified. The clinical profiles and medications required to control the disease activity were documented. Comparisons of clinical features and the medications used were made between patients with disease onset before and after 40 years of age. Results Seven late-onset BD patients were identified. Among them, five patients required the use of systemic immunosuppressant in addition to colchicine and corticosteroid for adequate disease control. There is no significant difference in clinical profiles between patients with disease onset before and after 40 years of age, but the incidence of uveitis, an indicator of unfavourable prognosis, was surprisingly high. More specifically, it was noted in four of seven patients identified. Conclusion Our findings indicate that the clinical course of BD is not indolent in the patients with late-onset BD. More importantly, physicians should be aware that BD can occur in older patients, and close attention regarding their disease activities is warranted as their clinical courses may not be as benign as previously believed.

This address was presented by Chien-ShiungWu as the Nishina Memorial Lecture at the University of Tokyo, March 31, 1983

We studied silver barrier ohmic (Ni/AuGe/Ag/Au) contacts to the GaAs based HEMT structures and observed strong dependence of the cleaning procedures on the ohmic con-tact resistance (Rc), its stability and reliability. The chemical profiles of the metal con-tacts before and after alloying were measured by SIMS. Samples cleaned with the com-bined plasma O2 and NH4OH process exhibited excellent results:R c ∼ 0.1–0.12 ohm-mm when alloyed in the temperature range of 440–540° C and remained stable when subjected to a 200° C and 600mA/mm stress condition for 1000 hr.

The catalytic dehydrogenation of ethylbenzene to styrene in a membrane reactor was studied at 600° to 640°C. The reactor selected in this study is a commercial alumina membrane tube with 40A pore diameter packed with granular catalysts. One of the reaction products, hydrogen, was separated through the membrane. Therefore, the catalytic dehydrogenation was enhanced by reducing the hydrogen partial pressure in the reactor. The conversion of ethylbenzene increased ∼15% compared to the conversion in the packed-bed reactor. The hydrothermal stability of membrane reactor after reactions was examined by nitrogen permeation test and SEM. It indicated that the pore diameter increased to 60 ∼ 90A and the microstructure of membrane remained intact.

Instabilities due to a cross-field ion flow are reexamined by including the electromagnetic response of the ions, which has been ignored in existing discussions. It is found that this effect can lead to significant enhancement of the growth rate. Among the new results, a purely growing, electromagnetic unstable mode with a wave vector k parallel to the ambient magnetic field is found. The plasma configuration under consideration is similar to that used in the discussion of the well-known modified-two-stream instability. This instability has a growth rate faster than the ion cyclotron frequency, and is not susceptible to high-plasma-beta stabilization.

A linear analysis is performed to investigate the kinetic cross-field streaming instability in the earth's magnetotail neutral sheet region. Numerical solution of the dispersion equation shows that the instability can occur under conditions expected for the neutral sheet just prior to the onset of substorm expansion. The excited waves are obliquely propagating whistlers with a mixed polarization in the lower hybrid frequency range. The ensuing turbulence of this instability can lead to a local reduction of the cross-tail current causing it to continue through the ionosphere to form a substorm current wedge. A substorm expansion onset scenario is proposed based on this instability in which the relative drift between ions and electrons is primarily due to unmagnetized ions undergoing current sheet acceleration in the presence of a cross-tail electric field. The required electric field strength is within the range of electric field values detected in the neutral sheet region during substorm intervals. The skew in local time of substorm onset location and the three conditions under which substorm onset is observed can be understood on the basis of the proposed scenario.

A new representation of the many-particle configuration space in the cranked shell model for well deformed nuclei is introduced. The single-particle states and the many-particle configurations are chosen as the simultaneous eigenstates of {ital J}{sub {ital z}}{sup 2} and {ital R}{sub {ital x}}({pi}), a rotation of 180{degree} about the {ital x} axis. The {ital K} structure of the low-lying eigenstates of the cranked shell model Hamiltonian {ital H}{sub CSM} is investigated in detail. It is shown that the accurate solutions to the low-lying bands of {ital H}{sub CSM} can be obtained easily by using a {ital K} truncation. The reduction in dimension of the many-particle configuration space achieved by the {ital K} truncation is quite considerable and the eigenstates obtained by using a suitable {ital K} truncation are almost identical to those obtained without {ital K} truncation.

In 0.1M tris. pH 7 buffer containing 0.5M LiNO3, PVPDMAEMA (which exists as a cationic polyelectrolyte) was found to elute based on hydrodynamic volume on Waters Ultrahydrogel columns. Within the exclusion limit of the column set an accurate weight average molecular weight of PVPDMAEMA can be obtained by universal calibration which is in very good agreement with the SEC/LALLS result.

On demontre cette augmentation en alterant la stœchiometrie pres de la surface avec une implantation d'As a basse energie. Cette augmentation n'est pas due a une couche de materiau isolant

Three distinct peaks at 80, 175, and 325°C were identified in the dynamic derivative TGA curves of PMVEMA and PMVEMAC at a 10°C/min heating rate. These peaks were attributed to free water removal, anhydride formation, and polymer degradation, respectively. The kinetics of the anhydride formation were studied by isothermal TGA in the temperature range of 150–200°C. It was found to be an endothermic and first-order intramolecular reaction with an activation energy of 18.8 kcal/mol. It was concluded from FT-IR and DSC results that no intermolecular anhydride structure was present in the dehydration of PMVEMAC. This is different from the cases of the dehydration of poly(acrylic acid) and poly(methacrylic acid) in the literature. The limiting glass transition temperatures of PMVEMA and PMVEMAC were found to be 153 and 144°C, respectively. The higher glass transition temperature in PMVEMA as compared to PMVEMAC is attributed to the increase in stiffness in the main polymer chain by the five-membered ring anhydride structure in PMVEMA.

Summary Background Both psoralen plus ultraviolet (UV) A (PUVA) and narrowband UVB (NB-UVB) irradiation are effective treatments for vitiligo vulgaris. However, the mechanisms of PUVA and NB-UVB in repigmentation are not thoroughly clarified. Our previous results showed that NB-UVB irradiation directly promotes melanocyte (MC) migration and stimulates MC proliferation via keratinocytes (KCs). Objectives In the present study, we used NB-UVB as a reference for comparison to investigate the immediate effects of PUVA on MC proliferation and migration. Methods Cultured MCs and KCs were treated with PUVA or irradiated with NB-UVB. The direct impact of PUVA treatment on MCs was assessed in terms of its effect on MC proliferation and migration. The indirect effect of PUVA treatment and NB-UVB irradiation on MC proliferation via KCs was also investigated. The activities of matrix metalloproteinase (MMP)-2 and MMP-9, known for their influence on cell migration, were evaluated in the PUVA-treated MC and KC supernatants. The concentrations of MC mitogens/growth factors in the PUVA-treated KC supernatants were also determined. In addition, the serum levels of MC mitogens/growth factors in healthy controls, in patients with active vitiligo and in patients with repigmenting vitiligo after PUVA treatment were determined to elucidate the mechanisms of how PUVA induces vitiligo repigmentation in vivo. Results Our results demonstrated that PUVA treatment did not significantly stimulate the release of MC mitogens/growth factors from KCs. The migration of MCs was also not enhanced after PUVA treatment. The expression of MMP-2 activity in supernatants derived from PUVA-treated MCs was significantly increased as compared with the control group. However, neither MMP-2 nor MMP-9 activity in KC supernatants was stimulated by PUVA treatment. In contrast to NB-UVB, immediate effects of PUVA on MC proliferation and migration were not observed in this study. Sera from patients with repigmenting vitiligo after PUVA treatment contained higher levels of basic fibroblast growth factor, stem cell factor and hepatocyte growth factor as compared with healthy controls and patients with active vitiligo. Conclusions Our results indicate that in addition to immune suppression, PUVA treatment creates a favourable milieu for promoting the growth of MCs in patients with vitiligo instead of directly stimulating the regrowth of MCs. Based on our results, we propose that in the active stage of vitiligo, PUVA treatment is the therapy of choice to slow down the destruction of MCs and to create a favourable environment for MCs to survive. In the stable stage of vitiligo, NB-UVB irradiation should be used to stimulate the proliferation and migration of MCs directly.