1,053 research outputs found
Optimized polar-azimuthal orientations for polarized light illumination of different Superconducting Nanowire Single-Photon Detector designs
The optimal orientations are determined for polarized substrate side
illumination of three superconducting nanowire single-photon detector (SNSPD)
designs: (1) periodic niobium-nitride (NbN) stripes standing in air with
dimensions according to conventional SNSPDs, (2) same NbN patterns below
~quarter-wavelength hydrogensilsesquioxane-filled nano-cavity, (3) analogous
NbN patterns in HSQ nano-cavity closed by a thin gold reflector. Numerical
computation results have shown that the optical response and near-field
distribution vary significantly with polar-angle, fi, and these variations are
analogous across all azimuthal-angles, gamma, but are fundamentally different
in various device designs. Larger absorptance is available due to p-polarized
illumination of NbN patterns in P-structure configuration, while s-polarized
illumination results in higher absorptance in S-structure arrangement. As a
result of p-polarized illumination a global maximum appears on absorptance of
bare NbN pattern at polar angle corresponding to NbN-related ATIR; integration
with HSQ nano-cavity results in a global absorptance maximum at polar angle
corresponding to TIR at sapphire-air interface; while the highest absorptance
is observable at perpendicular incidence on P-structures aligned below gold
reflector covered HSQ nano-cavity. S-polarized light illumination results in a
global absorptance maximum at TIR on bare NbN patterns; the highest absorptance
is available below HSQ nano-cavity at polar angle corresponding to ATIR
phenomenon; while the benefit of gold reflector is large and polar angle
independent absorptance.Comment: 24 pages, 7 figure
Developing E-learning Courses for Mobile Devices
The recent and rapid development of mobile devices and the increasing popularity of e learning have created a demand for mobile learning packages and environments. We have analyzed the possibilities of adapting the existing content for mobile devices, and have implemented two fundamentally different systems to satisfy the demand that has arisen. One of the systems creates e learning courses from existing materials and adapts them to the specified platform (this system realizes the functionalities of the Content Management System). The other system is a modified version of the Moodle Learning Management System, which can adapt existing courses right before displaying them. This paper discuses the fundamentals of e learning, the design considerations and investigates various methods of scalable video coding. Finally the realization details of the two systems are presented.
A szívfrekvencia-variabilitás jelentősen csökken nem diabeteses hypertoniás betegek körében
Bevezetés: A szívfrekvencia-variabilitás csökken hypertoniában vagy diabetes mellitusban szenvedők körében. A hypertonia és a diabetes mellitus egymással gyakori komorbiditást mutatnak. Nincs elegendő adat arról, hogy a kontrollhoz képest diabetes mellitusban nem szenvedő hypertoniás betegek körében hogyan változik a szívfrekvencia-variabilitás. Célkitűzés: A szerzők hypertoniában szenvedő diabeteses és nem diabeteses betegekben, valamint kontrollegyénekben a szívfrekvencia-variabilitás vizsgálatát tűzték ki célul. Módszer: 130 hypertoniában, 48 hypertoniában és 2-es típusú diabetes mellitusban szenvedő beteget, valamint 87 kontrollszemélyt vontak be a vizsgálatba. A minimális, átlagos és maximális szívfrekvenciát, valamint az egymást követő RR-intervallumok időtartamának és 5 perces szegmensekben mért átlagának szórását határozták meg. Eredmények: Az átlagos minimális szívfrekvencia szignifikánsan nem különbözött a csoportok között. A kontrollhoz képest a többi paraméter szignifikánsan csökkent mind a hypertoniában, mind a hypertoniában és diabetesben szenvedő betegek csoportjában. A hypertoniás csoporthoz képest a hypertoniában és diabetesben szenvedő csoportban a paraméterek nem különböztek szignifikánsan. Következtetések: Diabetes mellitusban nem szenvedő hypertoniás betegek körében a szívfrekvencia-variabilitás jelentősen beszűkül. Úgy tűnik, hogy hypertoniás betegek körében a 2-es típusú diabetes mellitus szignifikánsan már nem csökkenti tovább a szívfrekvencia-variabilitást. Orv. Hetil., 2014, 155(22), 865–870.
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Introductions: Heart rate variability is reduced among patients with hypertension or those with diabetes mellitus. Hypertension and diabetes show frequent co-morbidity, but it is still not entirely clear whether heart arte variability is reduced in non-diabetic patients with hypertension. Aim: The aim of the authors was to evaluate the heart rate variability in hypertensive patients with and without diabetes and in control subjects. Method: 130 patients with hypertension, 48 patients with hypertension and type 2 diabetes mellitus, and 87 control subjects were involved in the study. Minimum, mean and maximum heart rate, and parameters of heart rate variability were measured. Results: The mean of minimum heart rate did not differ significantly between the three groups. However, all other parameters were significantly reduced in patients with hypertension with and without diabetes as compared to the control group. No significant differences were observed between hypertensive patients with and without diabetes mellitus. Conclusions: Heart rate variability is significantly reduced in non-diabetic patients with hypertension. It seems that type 2 diabetes results in no further significant reduction of heart rate variability in patients with hypertension. Orv. Hetil., 2014, 155(22), 865–870
Identification of epidermal Pdx1 expression discloses different roles of Notch1 and Notch2 in murine KrasG12D-induced skin carcinogenesis in vivo
Background
The Ras and Notch signaling pathways are frequently activated during development to control many diverse cellular processes and are often dysregulated during tumorigenesis. To study the role of Notch and oncogenic Kras signaling in a progenitor cell population, Pdx1-Cre mice were utilized to generate conditional oncogenic KrasG12D mice with ablation of Notch1 and/or Notch2.
Methodology/Principal Findings
Surprisingly, mice with activated KrasG12D and Notch1 but not Notch2 ablation developed skin papillomas progressing to squamous cell carcinoma providing evidence for Pdx1 expression in the skin. Immunostaining and lineage tracing experiments indicate that PDX1 is present predominantly in the suprabasal layers of the epidermis and rarely in the basal layer. Further analysis of keratinocytes in vitro revealed differentiation-dependent expression of PDX1 in terminally differentiated keratinocytes. PDX1 expression was also increased during wound healing. Further analysis revealed that loss of Notch1 but not Notch2 is critical for skin tumor development. Reasons for this include distinct Notch expression with Notch1 in all layers and Notch2 in the suprabasal layer as well as distinctive p21 and β-catenin signaling inhibition capabilities.
Conclusions/Significance
Our results provide strong evidence for epidermal expression of Pdx1 as of yet not identified function. In addition, this finding may be relevant for research using Pdx1-Cre transgenic strains. Additionally, our study confirms distinctive expression and functions of Notch1 and Notch2 in the skin supporting the importance of careful dissection of the contribution of individual Notch receptors
Mid-infrared interferometric variability of DG Tau: implications for the inner-disk structure
Context. DG Tau is a low-mass pre-main sequence star, whose strongly
accreting protoplanetary disk exhibits a so-far enigmatic behavior: its
mid-infrared thermal emission is strongly time-variable, even turning the 10
m silicate feature from emission to absorption temporarily. Aims. We look
for the reason for the spectral variability at high spatial resolution and at
multiple epochs. Methods. We study the temporal variability of the mid-infrared
interferometric signal, observed with the VLTI/MIDI instrument at six epochs
between 2011 and 2014. We fit a geometric disk model to the observed
interferometric signal to obtain spatial information about the disk. We also
model the mid-infrared spectra by template fitting to characterize the profile
and time dependence of the silicate emission. We use physically motivated
radiative transfer modeling to interpret the mid-infrared interferometric
spectra. Results. The inner disk (r<1-3 au) spectra exhibit a 10 m
absorption feature related to amorphous silicate grains. The outer disk (r>1-3
au) spectra show a crystalline silicate feature in emission, similar to the
spectra of comet Hale-Bopp. The striking difference between the inner and outer
disk spectral feature is highly unusual among T Tauri stars. The mid-infrared
variability is dominated by the outer disk. The strength of the silicate
feature changed by more than a factor of two. Between 2011 and 2014 the
half-light radius of the mid-infrared-emitting region decreased from 1.15 to
0.7 au. Conclusions. For the origin of the absorption we discuss four possible
explanations: a cold obscuring envelope, an accretion heated inner disk, a
temperature inversion on the disk surface and a misaligned inner geometry. The
silicate emission in the outer disk can be explained by dusty material high
above the disk plane, whose mass can change with time, possibly due to
turbulence in the disk.Comment: 16 pages, 13 figure
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