2,880 research outputs found

    Primary Superficial Vein Reflux with Competent Saphenous Trunk

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    AbstractObjectives: because reflux in superficial vein tributaries is most often collectively reported with the main saphenous veins, its importance remains largely unrecognised. This study was designed to identify the distribution and extent of non-truncal superficial venous reflux and its association with the signs and symptoms of chronic venous disease (CVD). Patients and methods: eighty-four limbs in 62 patients with signs and symptoms of CVD and evidence of reflux on continuous-wave Doppler were subsequently examined with colour-flow duplex imaging. Incompetent superficial vein tributaries were imaged throughout their extent and both ends were identified. Limbs with reflux in the main trunk of the saphenous veins or the deep, perforator or muscular veins, superficial or deep vein thrombosis, injection sclerotherapy, varicose-vein surgery, arterial disease and inflammation of non-venous origin were excluded from the study. The CEAP classification system was used for staging clinical severity of CVD. Results: the prevalence of tributary reflux alone was 9.7% (84/860). Reflux was detected in 171 tributaries. The number of incompetent tributaries ranged from 1 to 5 per limb. Most prevalent were the tributaries to the greater saphenous (111, 65%<0.0001), followed by those of lesser saphenous (33, 19%) or a combination of both (12, 7%). Incompetent non-saphenous tributaries were uncommon (15, 9%). Among the named tributaries in the lower limb the posterior arch vein was most often incompetent (46, 27%) followed by the anterolateral vein of the thigh (30, 18%), the medial accessory vein (16, 9%) and the anterior arch vein (14, 8%). Reflux in above-the-knee tributaries alone was found in 18 limbs (21%), in below the knee in 23 (28%) and in both sites in 43 (51%). The vast majority of the limbs (71%,p <0.0001) belonged to CVD class 2, 14% in class 3, 9% in class 1 and only 6% in class 4. Class 3 and 4 patients tended to have a longer duration of signs and symptoms, higher number of incompetent tributaries per limb and also a higher prevalence of combined above- and below-knee reflux. Conclusions: these data indicate that reflux confined to superficial tributaries is found throughout the lower limb. Because this reflux is present without greater and lesser saphenous trunk, perforator and deep-vein incompetence or proximal obstruction, it shows that reflux can develop in any vein without an apparent feeding source. Greater saphenous tributaries are affected significantly more often than those of lesser saphenous, while non-saphenous reflux is uncommon. Most limbs have signs and symptoms of CVD class 2 and 15% belong in classes 3 and 4

    Improving the Representation of Cross-Boundary Transport of Anthropogenic Pollution in East Asia Using Radon-222.

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    We report on 10 years of hourly atmospheric radon, CO, and SO2 observations at Gosan Station, Korea. An improved radon detector was installed during this period and performance of the detectors is compared. A technique is developed whereby the distribution of radon concentrations from a fetch region can be used to select air masses that have consistently been in direct contact with land-based emissions, and have been least diluted en route to the measurement site. Hourly radon concentrations are used to demonstrate and characterise contamination of remote-fetch pollution observations by local emissions at this key WMO GAW site, and a seasonally-varying 5-hour diurnal sampling window is proposed for days on which diurnal cycles are evident to minimise these effects. The seasonal variability in mixing depth and “background” pollutant concentrations are characterised. Based on a subset of observations most representative of the important regional fetch areas for this site, and least affected by local emissions, seasonal estimates of CO and SO2 in air masses originating from South China, North China, Korea and Japan are compared across the decade of observations. 2016, © Taiwan Association for Aerosol Researc

    Grain Boundary Induced Bias Instability in Soluble Acene-Based Thin-Film Transistors

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    Since the grain boundaries (GBs) within the semiconductor layer of organic field-effect transistors (OFETs) have a strong influence on device performance, a substantial number of studies have been devoted to controlling the crystallization characteristics of organic semiconductors. We studied the intrinsic effects of GBs within 5,11-bis(triethylsilylethynyl) anthradithiophene (TES-ADT) thin films on the electrical properties of OFETs. The GB density was easily changed by controlling nulceation event in TES-ADT thin films. When the mixing time was increased, the number of aggregates in asspun TES-ADT thin films were increased and subsequent exposure of the films to 1,2-dichloroethane vapor led to a significant increase in the number of nuleation sites, thereby increasing the GB density of TES-ADT spherulites. The density of GBs strongly influences the angular spread and crystallographic orientation of TES-ADT spherulites. Accordingly, the FETs with higher GB densities showed much poorer electrical characteristics than devices with lower GB density. Especially, GBs provide charge trapping sites which are responsible for bias-stress driven electrical instability. Dielectric surface treatment with a polystyrene brush layer clarified the GB-induced charge trapping by reducing charge trapping at the semiconductor-dielectric interface. Our study provides an understanding on GB induced bias instability for the development of high performance OFETs.1172Ysciescopu

    Estimating Dynamic Gait Stability Using Data from Non-aligned Inertial Sensors

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    Recently, two methods for quantifying the stability of a dynamical system have been applied to human locomotion: local stability (quantified by finite time maximum Lyapunov exponents, λs and λL) and orbital stability (quantified by maximum Floquet multipliers, MaxFm). In most studies published to date, data from optoelectronic measurement systems were used to calculate these measures. However, using wireless inertial sensors may be more practical as they are easier to use, also in ambulatory applications. While inertial sensors have been employed in some studies, it is unknown whether they lead to similar stability estimates as obtained with optoelectronic measurement systems. In the present study, we compared stability measures of human walking estimated from an optoelectronic measurement system with those calculated from an inertial sensor measurement system. Subjects walked on a treadmill at three different speeds while kinematics were recorded using both measurement systems. From the angular velocities and linear accelerations, λs, λL, and MaxFm were calculated. Both measurement systems showed the same effects of walking speed for all variables. Estimates from both measurement systems correlated high for λs and λL, (R > 0.85) but less strongly for MaxFm (R = 0.66). These results indicate that inertial sensors constitute a valid alternative for an optoelectronic measurement system when assessing dynamic stability in human locomotion, and may thus be used instead, which paves the way to studying gait stability during natural, everyday walking

    The diacylglycerol kinase α/Atypical PKC/β1 integrin pathway in SDF-1α mammary carcinoma invasiveness

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    Diacylglycerol kinase α (DGKα), by phosphorylating diacylglycerol into phosphatidic acid, provides a key signal driving cell migration and matrix invasion. We previously demonstrated that in epithelial cells activation of DGKα activity promotes cytoskeletal remodeling and matrix invasion by recruiting atypical PKC at ruffling sites and by promoting RCP-mediated recycling of α5β1 integrin to the tip of pseudopods. In here we investigate the signaling pathway by which DGKα mediates SDF-1α-induced matrix invasion of MDA-MB-231 invasive breast carcinoma cells. Indeed we showed that, following SDF-1α stimulation, DGKα is activated and localized at cell protrusion, thus promoting their elongation and mediating SDF-1α induced MMP-9 metalloproteinase secretion and matrix invasion. Phosphatidic acid generated by DGKα promotes localization at cell protrusions of atypical PKCs which play an essential role downstream of DGKα by promoting Rac-mediated protrusion elongation and localized recruitment of β1 integrin and MMP-9. We finally demonstrate that activation of DGKα, atypical PKCs signaling and β1 integrin are all essential for MDA-MB-231 invasiveness. These data indicates the existence of a SDF-1α induced DGKα - atypical PKC - β1 integrin signaling pathway, which is essential for matrix invasion of carcinoma cells

    Speckle-free laser imaging

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    Many imaging applications require increasingly bright illumination sources, motivating the replacement of conventional thermal light sources with light emitting diodes (LEDs), superluminescent diodes (SLDs) and lasers. Despite their brightness, lasers and SLDs are poorly suited for full-field imaging applications because their high spatial coherence leads to coherent artifacts known as speckle that corrupt image formation. We recently demonstrated that random lasers can be engineered to provide low spatial coherence. Here, we exploit the low spatial coherence of specifically-designed random lasers to perform speckle-free full-field imaging in the setting of significant optical scattering. We quantitatively demonstrate that images generated with random laser illumination exhibit higher resolution than images generated with spatially coherent illumination. By providing intense laser illumination without the drawback of coherent artifacts, random lasers are well suited for a host of full-field imaging applications from full-field microscopy to digital light projector systems.Comment: 5 pages, 4 figure

    Melasma and its association with different types of nevi in women: A case-control study

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    <p>Abstract</p> <p>Background</p> <p>Very little is known about possible association of nevi and melasma. The study objective was to determine if there is an association between melasma and existence of different kinds of nevi.</p> <p>Methods</p> <p>In a case-control study, 120 female melasma patients referred to dermatology clinic of Ardabil and 120 patients referred to other specialty clinics who lacked melasma were enrolled after matching for age. Number of different types of nevi including lentigines and melanocytic nevi were compared between case and control group patients. Data were entered into the computer and analyzed by SPSS 13 statistical software.</p> <p>Results</p> <p>Mean number of lentigines was 25.5 in melasma group compared to 8 in control group(P < 0.01). Mean number of melanocytic nevi was 13.2 in cases compared to 2.8 in control group(P < 0.001). Multivariate analysis showed that existence of freckles, lentigines and more than three melanocytic nevi were positively related to developing melasma. The chance of melasma increased up to 23 times for patients having more than three melanocytic nevi. Congenital nevi were observed among 10% both in case and control groups. Campbell de morgan angiomas were seen among 26 patients(21.8%) in case group compared to 6 patients(5%) in control group.</p> <p>Conclusion</p> <p>Existence of lentigines and melanocytic nevi increases chance of having melasma</p
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