Medium Wavelength Research Articles

Uncooled middle wavelength infrared photoconductors based on (111) and (100) oriented HgCdTe

We present progress in metal organic chemical vapor deposition (MOCVD) growth of (100) HgCdTe epilayers achieved recently at the Institute of Applied Physics, Military University of Technology and Vigo System S.A. It is shown that MOCVD technology is an excellent tool for the fabrication of different HgCdTe detector structures with a wide range of composition, donor/acceptor doping, and without post grown ex-situ annealing. Surface morphology, residual background concentration, and acceptor doping efficiency are compared in (111) and (100) oriented HgCdTe epilayers. At elevated temperatures, the carrier lifetime in measured p-type photoresistors is determined by Auger 7 process with about one order of magnitude difference between theoretical and experimental values. Particular progress has been achieved in the growth of (100) HgCdTe epilayers for medium wavelength infrared photoconductors operated in high-operating temperature conditions.

Pias3 is necessary for dorso-ventral patterning and visual response of retinal cones but is not required for rod photoreceptor differentiation.

ABSTRACTProtein inhibitor of activated Stat 3 (Pias3) is implicated in guiding specification of rod and cone photoreceptors through post-translational modification of key retinal transcription factors. To investigate its role during retinal development, we deleted exon 2-5 of the mouse Pias3 gene, which resulted in complete loss of the Pias3 protein. Pias3−/− mice did not show any overt phenotype, and retinal lamination appeared normal even at 18 months. We detected reduced photopic b-wave amplitude by electroretinography following green light stimulation of postnatal day (P)21 Pias3−/− retina, suggesting a compromised visual response of medium wavelength (M) cones. No change was evident in response of short wavelength (S) cones or rod photoreceptors until 7 months. Increased S-opsin expression in the M-cone dominant dorsal retina suggested altered distribution of cone photoreceptors. Transcriptome profiling of P21 and 18-month-old Pias3−/− retina revealed aberrant expression of a subset of photoreceptor genes. Our studies demonstrate functional redundancy in SUMOylation-associated transcriptional control mechanisms and identify a specific, though limited, role of Pias3 in modulating spatial patterning and optimal function of cone photoreceptor subtypes in the mouse retina.

Microstructure and thermoelectric properties of Si-WSi2 nanocomposites

Nanocomposites of n-doped Si/WSi2 were prepared and morphologically and thermoelectrically investigated. The composites were densified by spark-plasma-sintering of doped Si nanoparticles with WSi2 nanoinclusions. The nanoparticles were synthesized in a gas-phase process. The microstructure of the bulk nanocomposite shows an inhomogeneous distribution of the WSi2 nanoinclusions in form of WSi2-rich and -depleted regions. This inhomogeneity is not present in the starting material and is assigned to a self-organizing process during sintering. The inhomogeneities are in the micrometer range and may act as scattering centers for long-wavelength phonons. The WSi2 nanoinclusions grow during sintering from originally 3–7 nm up to 30–143 nm depending on the total W content and might act as scattering centers for the medium wavelength range of phonons. Further, the growth of Si grains is suppressed by the WSi2 inclusions, which leads to an enhanced grain boundary density. Adding 1 at% W reduces lattice thermal conductivity by almost 35% within the temperature range from 300 K to 1250 K compared to pure, nanocrystalline silicon (doped). By addition of 6 at% W a reduction of 54% in lattice thermal conductivity is achieved. Although little amounts of W slightly reduce the power factor an enhancement of the thermoelectric figure of merit of 50% at 1250 K compared to a tungsten-free reference was realized.

On High-Frequency Topography-Implied Gravity Signals for a Height System Unification Using GOCE-Based Global Geopotential Models

National height reference systems have conventionally been linked to the local mean sea level, observed at individual tide gauges. Due to variations in the sea surface topography, the reference levels of these systems are inconsistent, causing height datum offsets of up to ±1–2 m. For the unification of height systems, a satellite-based method is presented that utilizes global geopotential models (GGMs) derived from ESA’s satellite mission Gravity field and steady-state Ocean Circulation Explorer (GOCE). In this context, height datum offsets are estimated within a least squares adjustment by comparing the GGM information with measured GNSS/leveling data. While the GNSS/leveling data comprises the full spectral information, GOCE GGMs are restricted to long wavelengths according to the maximum degree of their spherical harmonic representation. To provide accurate height datum offsets, it is indispensable to account for the remaining signal above this maximum degree, known as the omission error of the GGM. Therefore, a combination of the GOCE information with the high-resolution Earth Gravitational Model 2008 (EGM2008) is performed. The main contribution of this paper is to analyze the benefit, when high-frequency topography-implied gravity signals are additionally used to reduce the remaining omission error of EGM2008. In terms of a spectral extension, a new method is proposed that does not rely on an assumed spectral consistency of topographic heights and implied gravity as is the case for the residual terrain modeling (RTM) technique. In the first step of this new approach, gravity forward modeling based on tesseroid mass bodies is performed according to the Rock–Water–Ice (RWI) approach. In a second step, the resulting full spectral RWI-based topographic potential values are reduced by the effect of the topographic gravity field model RWI_TOPO_2015, thus, removing the long to medium wavelengths. By using the latest GOCE GGMs, the impact of topography-implied gravity signals on the estimation of height datum offsets is analyzed in detail for representative GNSS/leveling data sets in Germany, Austria, and Brazil. Besides considerable changes in the estimated offset of up to 3 cm, the conducted analyses show that significant improvements of 30–40% can be achieved in terms of a reduced standard deviation and range of the least squares adjusted residuals.

Effects of Liquid Medium and Ablation Wavelength on the Properties of Cadmium Sulfide Nanoparticles Formed by Pulsed-Laser Ablation.

Pulsed-laser ablation in liquid (PLAL) is a green synthesis technique to obtain semiconductor nanomaterials in colloidal form. Herein, cadmium sulfide (CdS) nanoparticles were synthesized by the pulsed-laser ablation of a CdS target in different liquid media by using λ=532 and 1064 nm outputs from a pulsed (10 ns, 10 Hz) Nd:YAG laser at different ablation fluence values. The morphology, structure, crystalline phase, elemental composition, optical, and luminescent properties of CdS nanomaterials were analyzed by using transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV/Vis absorption spectroscopy, and fluorescence spectroscopy. By changing the liquid medium and ablation wavelength, CdS nanoparticles with different morphology and size were formed, as demonstrated by using TEM analysis. The crystallinity and chemical states of the ablation products were confirmed by using XRD and XPS analyses. The optical bandgap of the CdS nanoparticles was dependent on the ablation wavelength and the fluence. These nanocolloids presented different green emissions, which implied the presence of several emission centers. CdS nanocolloids in distilled water catalyzed the photocatalytic decay of methylene blue dye under light irradiation from a solar simulator.

Numerical study on the optical and carrier recombination processes in GeSn alloy for E-SWIR and MWIR optoelectronic applications.

The Ge1-xSnx alloy is a promising material for optoelectronic applications. It offers a tunable wavelength in the infrared (IR) spectrum and high compatibility with complementary metal-oxide-semiconductor (CMOS) technology. However, difficulties in growing device quality Ge1-xSnx films has left the potentiality of this material unexplored. Recent advances in technological processes have renewed the interest toward this material paving the way to potential applications. In this work, we perform a numerical investigation on absorption coefficient, radiative recombination rate, and Auger recombination properties of intrinsic and doped Ge1-xSnx for application in the extended-short wavelength infrared and medium wavelength infrared spectrum ranges. We apply a Green's function based model to the Ge1-xSnx full electronic band structure determined through an empirical pseudopotential method and determine the dominant recombination mechanism between radiative and Auger processes over a wide range of injection levels.

Mesopic increment detection sensitivity, Part 2: Modelling mesopic detection sensitivity

This paper deals with the modelling of the mesopic detection sensitivity data described in Part 1. The modelling is based on a linear combination of the spectral sensitivity templates of four retinal mechanisms (long + medium wavelength sensitive cones, rods, short wavelength sensitive cones and long - medium wavelength sensitive cones opponency) to describe the experimental data on mesopic detection sensitivity and to provide a practically usable model. Model parameters representing the weighting of these mechanisms are analysed as a function of target eccentricity and background luminance.

Interpretation of gravity and magnetic data with geological constraints for 3D structure of the Thuringian Basin, Germany

We apply a novel method for the separation of potential field sources and their 3D inversion at the regional study area of Thuringian Basin in central Germany. The gravity and magnetic data are separated into long, medium and short wavelengths and then inverted separately. The main goal is to study uniqueness of the solution and its stability in all numerical steps of the interpretation process and to demonstrate, how geological constraints can diminish the degree of non-uniqueness by the interpretation of the gravity and magnetic anomalies. Our numerical experiments with medium wavelengths reveal that if we explain negative anomalies with the topography of near-surface layers, the obtained solution is not supported by borehole data. These negative anomalies are thus explained by restricted bodies (granitic intrusions) at the depths from 4 down to 10km. These bodies are located above a density interface with topography at the depth of approximately 10km. The 3D inversion of magnetic data (at short wavelengths) allows investigating a detailed structure of the upper boundary of the crystalline basement: two uplifts in the depths between 2.0 and 0.7km are found. By using the residual negative anomalies we further study the salt tectonics, showing that the geometry of a salt pillow with a thickness of approximately 200m closely agrees with borehole data.

Drug-Induced Deficits in Color Perception: Implications for Vision Rehabilitation Professionals

Along with the aging of the population, various comorbidities may arise, such as arthritis, hypertension, and erectile dysfunction (Glynn, Monane, Gurwitz, Choodnovskiy, & Avorn, 1999; Ramage-Morin, 2009). These medical conditions are treated and controlled with various types of medications. In fact, nearly 83% of older adults in Canada take prescription medications by age 65 years. Several of these medications can induce subtle side effects, including decreased visual perception. For instance, previous research indicated that side effects of commonly prescribed type-5 inhibitors (such as Viagra) may include declines in color perception (Azzouni & Abu Samra, 2011; Santaella & Fraunfelder, 2007). Many health care professionals, including vision rehabilitation therapists (VRTs), should be aware of the possibility of drug-induced deficits in color perception when working with older adults. The main purpose of this report is, therefore, to identify the commonly prescribed medications for age-related conditions that disturb color vision, and highlight the colors that are most frequently affected by these medications. This report aims to provide professionals who work with older adults with guidelines on how to identify individuals at risk for acquired color deficits and how to consider these insufficiencies during various rehabilitative interventions. A scoping review of the literature was conducted to identify the most commonly prescribed medications for age-related conditions like arthritis that can potentially alter color perception. An advanced search in the following databases was conducted: PubMed, EBSCO, and Google Scholar. The main Medical Subject Heading (MeSH) terms that were used in combination in searching for peer-reviewed articles included: acquired color deficits, drug-induced color deficits, side effects, medications, color vision, drug toxicity, hydroxychloroquine, type-5 inhibitor, plaquenil, ocular adverse effects, and retinal toxicity. Key words found in relevant articles were added to the search terms. In addition, Boolean terms such as and and or were used to refine the quest for relevant articles. MEDICATIONS AFFECTING COLOR VISION Color perception is made possible by three cone cell types embedded in the retina that are preferentially sensitive to different wavelengths of light. The S-cones are sensitive to short wavelengths (420 nanometers [nm]; also known as blue-cone). A deficit or absence in S-cones results in tritanopia, causing a blue-yellow color deficit or blindness. Similarly, the M-cones are sensitive to medium wavelengths (535 nm; also known as green-cone) and the L-cones to long wavelengths (565 nm; also known as redcone). The absence of M- or L-cones results in deuteranopia or protanopia, respectively. A deficit in any cone type results in a decreased ability to detect color hues. Given that the eye is a high-metabolism organ that contains many blood vessels, it is susceptible to the effects of systemic medications (Santaella & Fraunfelder, 2007). It was long thought that congenital color deficits were more common than acquired ones. In fact, approximately 8% of males and 0.5% of females are diagnosed with a congenital color deficit (Simunovic, 2010). However, some researchers argue that acquired color deficits are more prevalent than previously thought; a study conducted in North America revealed that the prevalence rate is 20.8% for older adults between ages 58 and 102 years (M = 75.2) (Simunovic, 2016). The effects of acquired color deficits can vary widely. For instance, some may develop problems in the red-green color axis (deuteranopia/protanopia), and others in the yellowblue axis (tritanopia). Nevertheless, the most common type of acquired color deficit is in the blue-yellow axis. An Iranian study revealed that 66.1% of acquired color deficits result in tritanopia (Jafarzadehpur et al., 2014). There are several causes for declines in color perception, but the most common ones are natural decline with age or as a result of medication intake (Delpero, O'Neill, Casson, & Hovis, 2005). …

Creating flat-top X-ray beams by applying surface profiles of alternating curvature to deformable piezo bimorph mirrors.

Beam shaping is becoming increasingly important for synchrotron X-ray applications. Although routine for visible light lasers, this is challenging for X-rays due to the limited source coherence and extreme optical tolerances required for the shaping mirrors. In deliberate defocusing, even surface errors <5 nm r.m.s. introduce damagingly large striations into the reflected beam. To counteract such problems, surface modifications with alternating concave and convex curvature on equal segments were polished onto the surface of non-active mirrors of fixed curvature. Such optics are useful for providing a fixed size of X-ray beam, but do not provide the adaptability required by many experiments. In contrast, deformable piezo bimorph mirrors permit a continuous range of X-ray beam sizes and shapes. A new theory is developed for applying non-periodic modifications of alternating curvature to optical surfaces. The position and length of the segments may be freely chosen. For the first time, surface modifications of alternating curvature are applied to bimorph mirrors to generate non-Gaussian X-ray beam profiles of specified width. The new theory's freedom is exploited to choose the segments to match the polishing errors of medium wavelength (>10 mm) and the piezos' influence on the mirror's figure. Five- and seven-segment modifications of alternating curvature are calculated and verified by visible light and X-ray metrology. The latter yields beam profiles with less striation than those made by defocusing. Remaining beam striations are explained by applying geometrical optics to the deviations from the ideal surface modifications of alternating curvature.

Neutral point testing of color vision in the domestic cat

Despite extensive study, the basic nature of feline spectral sensitivity is still unresolved. Most electrophysiological studies have demonstrated two photopic receptors within the cat's retina, one most sensitive to longer wavelengths near 560 nm and the other most sensitive to shorter wavelengths near 460 nm, providing the neuroretinal basis for dichromatic vision. A few studies, however, have detected a third photopic receptor most sensitive to medium wavelengths between 500 and 520 nm, overlapping in spectrally sensitivity with the feline scotopic receptor, that potentially could allow trichromatic vision. Indeed, one behavioral study has demonstrated trichromatic vision in cats, but a flaw within its experimental design raises the possibility that achromatic intensity cues might have allowed the accurate identification of medium wavelength targets. This study tested for a spectral neutral point in the domestic cat using a two-choice discrimination task. The positive targets were created using monochromatic light from various single wavelength light emitting diodes (LEDs) combined with a white light of variable intensity, while the negative targets were created using white light of variable intensity. Trials were performed with varying intensities of positive and negative targets, from brighter positive targets to brighter negative targets, to eliminate achromatic intensity cues. Two cats with prior experience with two-choice discrimination tasks, one male and one female, successfully discriminated monochromatic light from 456 nm to 497 nm and from 510 nm to 524 nm, but both failed to discriminate monochromatic light at 505 nm over multiple trials. These results provide strong evidence that cats are dichromatic with a neutral point near 505 nm. This neutral point is nearly identical to the neutral point of the human deuteuranope, making feline vision a more accurate a model for red-green colorblind individuals than normal trichromats.

Exploring the superfocusing performance of plasmonic lenses formed by coupled nanoslits

A comprehensive investigation on the superfocusing performance of a plasmonic lens formed by coupled metallic nanoslits is carried out. Based on the geometrical optics and the wavefront reconstruction principle, the nanoslit array for a plasmonic lens is optimally designed to achieve the desired phase modulation by considering the influence of the coupling between adjacent aperiodic nanoslits on phase delay and the theory of periodic metallic nanoslits. The designed lens' focusing behaviour is verified by using the finite-difference time-domain method. Numerical results demonstrate that the superfocusing performance of a plasmonic lens has a close relationship with the lens size, focal length, working medium and incident wavelength. A larger lens size, a shorter focal length, a higher-index working medium can contribute to producing a higher-resolution superfocusing. Moreover, due to the material response, a shorter wavelength is not beneficial for an efficient focusing.

Effect of High-Temperature and High-Pressure Processing on the Structure and Thermoelectric Properties of Clathrate Ba8Ga16Ge30

The n-type polycrystalline materials of Ba8Ga16Ge30 bulks have been successfully synthesized via the high-temperature and high-pressure (HPHT) method, and their crystal structure has been characterized using the X-ray diffraction. Through the thermoelectric properties measurements and microstructure studies, we know that the improvement of the dimensionless thermoelectric figure-of-merit (ZT) benefits from the low lattice thermal conductivity due to the increased low, medium, and high wavelength phonon scattering by grain boundaries, nanostructures, nanoscale domains, and lattice defects, which are ubiquitous in the synthetic bulk material. As the temperature increases, the power factor (PF) obviously increases, and the thermal conductivity evidently decreases. A minimum thermal conductivity of 0.71 W m–1 K–1 was reached at 773 K for Ba8Ga16Ge30 synthesized at 4 GPa. A good ZT value 1.14 was achieved, which was attributed to not only the enhanced PF but also the relative low thermal conductivity.

Effects of track irregularities on environmental vibration caused by underground railway

Abstract A mixed two- and three-dimensional model is developed to simulate the dynamic track-tunnel-soil interaction in underground railway with ballastless track taking into account the moving train comprising a number of carriages, the track irregularities, and interaction among various components of the system. The effects of different track irregularities on the environmental vibration generated by underground railway with direct fixation and floating slab tracks are investigated. The results show that random track irregularities have large effects on the environmental vibration compared with perfectly smooth track condition. For direct fixation tracks, the environmental vibration induced by the irregularity of short wavelength is more significant than that induced by the irregularity of medium wavelength. However, for floating slab tracks, the environmental vibration induced by the irregularity of short wavelength is less significant than that induced by the irregularity of medium wavelength. The track irregularity samples measured by track geometry measuring car should therefore be used together with the short-wavelength random track irregularity for accurate prediction of the environmental vibration induced by underground railway with direct fixation track.

Gravity field anomalies from recent GOCE satellite-based geopotential models and terrestrial gravity data: a comparative study over Saudi Arabia

Global geopotential models (GGMs) provide important information about the Earth gravity field in terms of precise gravity anomaly, gravity disturbance, and geoid height on global and regional scales. The GGMs based on the Gravity Recovery and steady-state Ocean Circulation Explorer (GOCE) satellite gravity mission provided by the International Center for Global Earth Models (ICGEM) differ in their accuracy and spatial resolution. In this paper, we evaluate the free-air gravity anomalies and geoid heights determined from several recent GOCE-based GGMs using the corresponding gravity functions (i.e., gravity anomalies and geoid heights) obtained from the Earth Gravitational Model 2008 (EGM2008) over the Kingdom of Saudi Arabia (KSA). Moreover, free-air gravity anomalies determined from GOCE-based GGMs have also been compared with the corresponding ones obtained from ground-based “terrestrial” gravity measurements over the study area. The latter comparison, using the available 3500 terrestrial gravity observations, applies the spectral enhanced method (SEM). We use the SEM to compensate the missed high-frequency component of geoid heights in GOCE-based GGMs using EGM2008 and a high-resolution digital terrain model based on the Shuttle Radar Topography Mission (SRTM). The statistical comparisons of the computed results in terms of free-air gravity anomalies and geoid heights obtained from GOCE-based GGMs are in general agreement. The estimated standard deviations of differences are 5 mGal (20 cm), 6–7 mGal (22–24 cm), and 8 mGal (25.9 cm) at spherical harmonic (SH) degree/order (d/o) 200, 240, and 280, respectively. Free-air gravity anomalies computed from available terrestrial gravity data, using the SEM, have been compared with the corresponding ones estimated from GOCE-based GGMs, and the results indicate an improvement over EGM2008 in the medium wavelengths. Investigation of various releases of GOCE-based GGM, up to d/o 200, reveals that the fourth and fifth releases of GOCE-based GGMs developed with the use of time-wise solution strategies (TIM_R4 and TIM_R5) approximate the gravity field well over the KSA region, since they provide the least standard deviation differences at SH. Thus, the TIM_R5 and TIM_R4 are suggested as reference models for recovering the long wavelength up to SH d/o 200 and 240, respectively, when modeling the gravimetric quasi-geoid over the KSA area.

Laser processing for bevel termination of high voltage pn junction in SiC

Proper edge termination of the p-n junction in silicon carbide is a key requirement in the fabrication of discrete devices able to withstand high voltages in reverse polarization. Due to the hardness of SiC the creation of the bevel termination remains difficult using mechanical machining. The use of laser beam sources with medium wavelength (532 nm) gives new possibilities in the machining of the silicon carbide. The paper presents the fabrication of the bevel termination structure in SiC using a green DPSS laser equipped with scanner and dedicated rotating sample holder. Characterization of the resulting structures proves the high potential of the proposed approach.

Considering the Influence of Nonadaptive Evolution on Primate Color Vision.

Color vision in primates is variable across species, and it represents a rare trait in which the genetic mechanisms underlying phenotypic variation are fairly well-understood. Research on primate color vision has largely focused on adaptive explanations for observed variation, but it remains unclear why some species have trichromatic or polymorphic color vision while others are red-green color blind. Lemurs, in particular, are highly variable. While some species are polymorphic, many closely-related species are strictly dichromatic. We provide the first characterization of color vision in a wild population of red-bellied lemurs (Eulemur rubriventer, Ranomafana National Park, Madagascar) with a sample size (87 individuals; NX chromosomes = 134) large enough to detect even rare variants (0.95 probability of detection at ≥ 3% frequency). By sequencing exon 5 of the X-linked opsin gene we identified opsin spectral sensitivity based on known diagnostic sites and found this population to be dichromatic and monomorphic for a long wavelength allele. Apparent fixation of this long allele is in contrast to previously published accounts of Eulemur species, which exhibit either polymorphic color vision or only the medium wavelength opsin. This unexpected result may represent loss of color vision variation, which could occur through selective processes and/or genetic drift (e.g., genetic bottleneck). To indirectly assess the latter scenario, we genotyped 55 adult red-bellied lemurs at seven variable microsatellite loci and used heterozygosity excess and M-ratio tests to assess if this population may have experienced a recent genetic bottleneck. Results of heterozygosity excess but not M-ratio tests suggest a bottleneck might have occurred in this red-bellied lemur population. Therefore, while selection may also play a role, the unique color vision observed in this population might have been influenced by a recent genetic bottleneck. These results emphasize the need to consider adaptive and nonadaptive mechanisms of color vision evolution in primates.

On the impact of airborne gravity data to fused gravity field models

In gravity field modeling, fused models that utilize satellite, airborne and terrestrial gravity observations are often employed to deal with erroneous terrestrially derived gravity datasets. These terrestrial datasets may suffer from long-wavelength systematic errors and inhomogeneous data coverage, which are not prevalent in airborne and satellite datasets. Airborne gravity acquisition plays an essential role in gravity field modeling, providing valuable information of the Earth’s gravity field at medium and short wavelengths. Thus, assessing the impact of airborne gravity data to fused gravity field models is important for identifying problematic regions. Six study regions that represent different gravity field variability and terrestrial data point-density characteristics are investigated to quantify the impact of airborne gravity data to fused gravity field models. The numerical assessments of these representative regions resulted in predictions of airborne gravity impact for individual states and provinces in the USA and Canada, respectively. Prediction results indicate that, depending on the terrestrial data point-density and gravity field variability, the expected impact of airborne gravity can reach up to 3mGal (in terms of standard deviation) in Canada and Alaska (over areas of 1\(^{\circ }\,\times \, \)1\(^{\circ })\). However, in the mainland US region, small changes are expected (0.2–0.4 mGal over areas of 1\(^{\circ }\,\times \, \)1\(^{\circ })\) due to the availability of high spatial resolution terrestrial data. These results can serve as a guideline for setting airborne gravity data acquisition priorities and for improving future planning of airborne gravity surveys.

Recent progress in MOCVD growth for thermoelectrically cooled HgCdTe medium wavelength infrared photodetectors

The authors report on advanced metalorganic chemical vapour deposition (MOCVD) of Hg1−xCdxTe (HgCdTe) structures for high operating temperature, medium wavelength infrared (MWIR) detector application. MOCVD technology with wide range of composition and donor/acceptor doping and without post grown annealing was proved to be an excellent tool for HgCdTe heterostructure epitaxial growth used for uncooled photodetector design. The interdiffused multilayer process (IMP) technique was applied for the HgCdTe deposition. HgCdTe epilayers were grown at 350°C with Hg source kept at 210°C. The II/VI mole ratio was assumed in the range from 1.5 to 3 during CdTe/HgTe cycles of the IMP process.The MWIR detectors grown by MOCVD exhibit detectivity ∼7.3×1011Jones at λPEAK=3.5μm and T=230K being determined by background limited photodetector (BLIP) condition.

Experience of Phototherapy in Dermatological Praxis in Complex Therapy of Psoriasis Patients

Abstract Psoriasis is a chronic relapsing skin disease presenting with erythematous and papulous lesions with infiltration and extensive desquamation on the skin surface. It is a genetically determined, multifactorial dermatosis where genetic, immune, and environmental factors play significant roles in its development. In Latvia in treatment of different forms of extensively spreading psoriasis, PUVA (psoralen and ultraviolet A light therapy), a combined method, is administered, applying long-wave UVA radiation with wavelength 320–400 nm in combination with photosensibilisator 8-metoxypsoralen and medium wave length UVB radiation narrow-band phototherapy — 311 nm using specialised TL-01 lamps. The aim of our clinical investigation was to determine the efficacy of narrow-band phototherapy (UVB 311 nm) in the complex treatment of patients with different severity of extensive psoriatic lesions treated in the Clinical Centre of Skin and Sexually Transmitted Diseases. Cases of clinical data of 260 patients with widely spread psoriasis were analysed. In the Group 1 (n = 102) receiving narrow-band UVB therapy, the mean and cumulative UVB dosage was 1.8 ± 0.6 and 21.5 ± 3.8 J/cm2, respectively, whereas in Group 2 (n = 91) it was 2.2 ± 0.1 and 27.7 ± 8.0 J/cm2. To obtain clinical recovery, 18 to 30 procedures were necessary (average 22 ± 4.1) with total irradiation dose received 110 ± 4.6 J/cm2. In 67 patients of the control group, PUVA therapy was administered, and positive therapeutic efficacy was observed in all patients. Clinical recovery was obtained in 86.2% in patients of the Group 1, in 82.4% — of Group 2, and in 80% — in 67 patients of the control group. Narrow-band (311 nm) UVB phototherapy is currently one of the leading pathogenetical methods of treatment of patients with widespread psoriasis. It has high efficacy, good tolerability, does not have severe side effects and restrictions in use, in comparison with traditional PUVA therapy.