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The thermal stability of thin films (3 nm) of transition-metal (TM) oxides (TiO2, ZrO2, and HfO2) grown on ultrathin (∼0.5 nm) SiO2 buffer layers on Si(100) surfaces was investigated with ultraviolet photoelectron emission microscopy (UV-PEEM). The decomposition of the TM oxides was observed in the PEEM during ultrahigh-vacuum annealing at temperatures of ∼870, ∼900, and ∼1000 °C for the TiO2, ZrO2, and HfO2, respectively. Following the decomposition reaction, atomic force microscopy measurements of the annealed surfaces revealed a high density of islands in the decomposed regions. The degradation of the TM oxide films is attributed to a reaction occurring at defects at the TM oxide/SiO2/Si interfaces, which forms SiO species. Once a portion of the interfacial SiO2 layer is desorbed as a result of this reaction, Si from the substrate can diffuse into contact with the TM oxide layer, resulting in the formation of a TM silicide and the evolution of SiO. This process continues until the entire TM oxide layer is consumed and only silicide islands remain. [ABSTRACT FROM AUTHOR]

This study explores the evolution of nanoscale islands and wire structures during deposition and surface ripening. Ultraviolet photoelectron emission microscopy has been employed to study the real time growth process of individual erbium silicide nanostructures on Si(001) surfaces at temperatures up to 1050°C. During the initial island formation process compact islands form and some undergo a shape transition to elongated islands oriented along the 〈110〉 directions of the Si substrate. The initial island formation is driven by the surface and interface energies of the silicide/ Si structure. The widths of the growing islands remain essentially constant while the lengths increase. The observed elongated islands are ∼150 nm wide, which is larger than the width of prior reported erbium silicide nanowire structures. We propose that the ∼150 nm elongated islands are partially relaxed, possibly through the formation of misfit dislocations. The results indicate a temperature regime where island growth is mainly governed by surface diffusion of the deposited Er adatoms and a higher temperature regime where Ostwald ripening contributes to the island morphology. [ABSTRACT FROM AUTHOR]

In this article we determine descriptive scattering parameters—haze and angular distribution functions—of scattered light for textured glass/SnO[sub 2] Asahi U-type substrates. These scattering parameters are input parameters of our optical model that enables us to analyze multilayer optical systems with rough interfaces. The scalar scattering theory is used to calculate the haze parameters of all internal rough interfaces in the a-Si:H solar cells deposited on the glass/SnO[sub 2] substrates. In the equations of the scalar scattering theory the correction functions are introduced in order to match the calculations with the measurements of the haze parameters of the substrates. The angular distribution functions of the substrates are applied to the rough internal interfaces. Using these scattering parameters we investigate the optical behavior of a-Si:H solar cells with different intrinsic layer thicknesses deposited on the textured glass/SnO[sub 2] substrates with different roughnesses. [ABSTRACT FROM AUTHOR]

An approach to study the optical behavior of hydrogenated amorphous silicon solar cells with rough interfaces using computer modeling is presented. In this approach the descriptive haze parameters of a light scattering interface are related to the root mean square roughness of the interface. Using this approach we investigated the effect of front window contact roughness and back contact material on the optical properties of a single junction a-Si:H superstrate solar cell. The simulation results for a-Si:H solar cells with SnO[sub 2]:F as a front contact and ideal Ag, ZnO/Ag, and Al/Ag as a back contact are shown. For cells with an absorber layer thickness of 150-600 nm the simulations demonstrate that the gain in photogenerated current density due to the use of a textured superstrate is around 2.3 mA cm[sup -2] in comparison to solar cells with flat interfaces. The effect of the front and back contact roughness on the external quantum efficiency (QE) of the solar cell for different parts of the light spectrum was determined. The choice of the back contact strongly influences the QE and the absorption in the nonactive layers for the wavelengths above 650 nm. A practical Ag back contact can be successfully simulated by introducing a thin buffer layer between the n-type a-Si:H and Ag back contact, which has optical properties similar to Al, indicating that the actual reflection at the n-type a-Si:H/Ag interface is smaller than what is expected from the respective bulk optical parameters. In comparison to the practical Ag contact the QE of the cell can be strongly improved by using a ZnO layer at the Ag back contact or an ideal Ag contact. The photogenerated current densities for a solar cell with a 450 nm thick intrinsic a-Si:H layer with ZnO/Ag and ideal Ag are 16.7 and 17.3 mA cm[sup -2], respectively, compared to 14.4 mA cm[sup -2] for the practical Ag back contact. The effect of increasing the roughness of the contact interfaces was investigated for both... [ABSTRACT FROM AUTHOR]

Examines the basic properties of hydrogenated amorphous silicon-germanium (a-SiGe:H) alloys deposited by plasma-enhanced chemical-vapor deposition. Comparison between the optical band gap of a-SiGe:H and a-Si:H alloys; Analysis of the effect of postgrowth anneal on the optical and electrical properties of a-SiGe:H alloys; Correlation of the changes in the defect density with the hydrogen and germanium concentrations in the alloys and changes in the optical gap; Details of the measured values of the optical gap and photosensitivity with variation of the growth and annealing temperatures for a-SiGe alloys.

Vacuum-compression therapy is one of the most effective mechanical therapy methods for physical therapy. Automatic alternation of the vacuum and overpressure phase in a hermetically sealed application cylinder greatly influences limb blood vessels and works in the treatment of various blood circulation, metabolism and nutrition disorders - especially in complications of diabetes, polyneuropathies, leg ulcers and post-traumatic conditions associated with swelling. In post-traumatic and postoperative conditions, the rate of regeneration and recovery of tissue energy parameters is very important and has a significant effect on the overall recovery time. The advantage of the spa environment when applying this therapy is the simultaneous action of other forms of physical therapy that potentiate its effectiveness. The paper describes the procedure and course of therapy in a patient with chronic perimaleolar swelling within 28 days of comprehensive spa treatment, where the condition was significantly improved, edema was reduced and mobility improved. [ABSTRACT FROM AUTHOR]

In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists. [ABSTRACT FROM AUTHOR]

The development of clean hydrogen and photovoltaic (PV) systems is lagging behind the goals set in the Net Zero Emissions scenario of the International Energy Agency. For this reason, efficient hydrogen production systems powered from renewable energy need to be deployed faster. This work presents an optimization procedure for a stand-alone, fully PV-powered alkaline electrolysis system. The approach is based on the Particle Swarm Optimization algorithm to obtain the best configuration of the PV plant that powers the electrolyzer and its compressor. The best configuration is determined with one of three indicators: cost, efficiency, or wasted energy. The PV plant needs to be oversized 2.63 times with respect to the electrolyzer to obtain minimum cost, while for high efficiency, this number increases by 2%. Additionally, the configuration that minimizes cost, wasted energy or maximizes efficiency does not correspond to the configuration that maximizes the annual PV yield. Optimizing for cost results also leads to the best operation of the electrolyzer at partial loads than optimizing for efficiency or wasted energy. • Optimization of stand-alone hydrogen system fully powered by PV. • Analysis of the orientation of the PV modules as decision variables. • Definition of three performance indicators. • Analysis of operation at partial loads. [ABSTRACT FROM AUTHOR]

The cold cracking process in MAG welding, microstructure and mechanical properties of ultra-high strength steel Weldox 1300 were investigated. It has been shown that the microstructure of the Weldox 1300 steel is composed of tempered martensite and inside the lathes the minor precipitations mainly V(CN) and molybdenum carbide Mo2C were observed. A Tekken cold cracking test was used to assess the weldability of steel at two different net heat input and different preheating temperatures in the range of 20-200 °C. The experimental results showed that the heat input and preheating temperature decided of tendency to cold cracking and the optimal preheating temperature was 100 °C. Additionally the results revealed that the analytical formulas of calculating the preheating temperature are not useful for this kind of steel. [ABSTRACT FROM AUTHOR]

The growth and coarsening dynamics of dysprosium silicide nanostructures are observed in real-time using photoelectron emission microscopy. The annealing of a thin Dy film to temperatures in the range of 700–1050 °C results in the formation of epitaxial rectangular silicide islands and nanowires on Si(001) and triangular and hexagonal silicide islands on Si(111). During continuous annealing, individual islands are observed to coarsen via Ostwald ripening at different rates as a consequence of local variations in the size and relative location of the surrounding islands on the surface. A subsequent deposition of Dy onto the Si(001) surface at 1050 °C leads to the growth of the preexisting islands and to the formation of silicide nanowires at temperatures above where nanowire growth typically occurs. Immediately after the deposition is terminated, the nanowires begin to decay from the ends, apparently transferring atoms to the more stable rectangular islands. On Si(111), a low continuous flux of Dy at 1050 °C leads to the growth of kinked and jagged island structures, which ultimately form into nearly equilateral triangular shapes. [ABSTRACT FROM AUTHOR]

Abstract: Computer modelling has become increasingly important in the design and optimization of surface textures that are used in thin-film solar cells to manipulate scattering of light. Light scattering at rough interfaces together with efficient back reflector is a standard approach to enhance absorption of light in the absorber layers of thin-film silicon solar cells. Substrates with randomly textured surface are commonly used to introduce rough interfaces into solar cells. Scalar scattering theory was used to describe light scattering at random nano-textured interfaces and to optimize random texture in single junction solar cells. Recently, substrates with periodic surface features have been investigated as an alternative to randomly surface-textured substrates. Three-dimensional Maxwell equation solvers were used to analyse and optimize such periodic textures when embedded in single and multi-junction solar cells. In both random and periodic cases, opto-electrical modelling was employed to assess the spectral response, to evaluate optical losses and to simulate current density–voltage characteristic. [Copyright &y& Elsevier]

A systematic structural analysis was carried out on amorphous silicon films prepared from hydrogen-diluted silane using plasma-enhanced chemical vapor deposition. Hydrogen dilution of silane during the growth of a-Si:H absorber layers is used to suppress light-induced degradation of a-Si:H solar cells. Transmission electron microscopy (TEM) shows that for higher hydrogen dilution ratios the growth of films becomes strongly inhomogeneous and the transition from amorphous to microcrystalline phase occurs at a smaller thickness. A detailed X-ray diffraction (XRD) analysis of the amorphous films reveals that the strongest peak in the XRD patterns is located around 27.5° and corresponds to the signal from the ordered domains of tetragonal silicon hydride and not from cubic silicon crystallites. The full width at half maximum of this peak narrows from 5.1° to 4.8° as the ratio of hydrogen to silane flow (R) increases to 20 and does not change significantly for higher hydrogen dilutions. The presence of silicon hydride ordered domains in amorphous films is confirmed by the lattice imaging method applied to the high resolution TEM recordings. The amorphous silicon films fabricated at different hydrogen dilution were applied as absorber layers in single-junction solar cells. The degradation experiment confirms that the cells with absorber layers deposited using hydrogen dilution are more stable to light exposure. A clear reduction of the degradation is observed when the dilution ratio is increased from R = 0 to R = 20. The degradation of solar cells with absorber layers prepared at R > 20 is not reduced by further increasing R. [ABSTRACT FROM AUTHOR]

Background Variable methods are available for secondary prevention after oesophageal variceal bleeding (EVB). Aim To compare band ligation (BL), pharmacotherapy (PT) and BL+PT for EVB secondary prevention. Methods A systematic search of databases, references and meeting abstracts was conducted for randomized trials of BL, PT or BL+PT. The outcomes were mortality, rebleeding and adverse events. A random-effects model was used for meta-analyses. Results Twelve trials were included (6 BL vs. PT, 4 BL+PT vs. BL, 2 BL+PT vs. PT). All trials used beta-blockers ± isosorbide mononitrate (ISMN) as PT. Mortality was not significantly different among trials. Rebleeding was not significantly different for BL vs. PT (RR 1.00, 95% CI 0.73–1.37). BL reduced rebleeding compared with PT for trials with mean beta-blocker dose <80 mg/day (RR 0.67, 95% CI 0.49–0.91). There were nonsignificant differences in rebleeding for BL+PT vs. BL (RR 0.57, 95% CI 0.31–1.08) and BL+PT vs. PT (RR 0.76, 95% CI 0.56–1.03). There was no difference in adverse events between BL vs. PT, but was higher with BL+PT vs. BL. Conclusion Band ligation and PT alone are comparable for secondary prevention of rebleeding after EVB. Further trials with adequate PT dosing are required to determine the efficacy of combination BL+PT therapy. [ABSTRACT FROM AUTHOR]

Abstract: The relation between the open-circuit voltage (V oc) of hydrogenated amorphous silicon (a-Si:H) solar cells and the band gap of the absorber layer has been investigated by changing the substrate temperature of the absorber layer. By decreasing the substrate temperature from 200°C to 150°C the V oc has increased by 0.05V. However, the temperature dependence of the V oc is larger than the change of the optical band gap of individual intrinsic layers, which indicates that also other absorber layer properties play an important role. Using simulations the effect of changing the mobility gap of as well the absorber layer as the buffer layer at the p–i interface on the performance of a-Si:H solar cells has been investigated. The recombination rate profile in the solar cell at the V oc is a useful tool to analyze and optimize different parts of the solar cell to obtain a high V oc. The simulations confirm the trend of increasing the V oc when implementing absorber layers with a higher mobility gap. The simulations demonstrate that increasing the mobility gap of the buffer layer at the p–i interface results in a further improvement of the V oc, however an optimal value of the mobility gap is found with respect to the conversion efficiency. [Copyright &y& Elsevier]

Abstract: Some patients with hypertension exhibit disturbed circadian organization in the cardiovascular system. Hormone melatonin can synchronize circadian rhythms and its repeated administration can improve synchronization of rhythmicity in blood pressure (BP). In our study we measured endogenous melatonin production in patients with essential hypertension exhibiting a dipping and non-dipping BP profile. Blood pressure was monitored for at least 24-hr with an automatic ambulatory BP monitor and patients with no decline in BP were classified as non-dippers. Plasma melatonin was measured in the middle of the daytime and night-time by radioimmunoassay. As expected night-time systolic (P &#60; 0.05), diastolic (P &#60; 0.001) and mean arterial (P &#60; 0.001) BP was higher in non-dippers than in dippers. No significant difference was found between both groups in BP during the day. Mean melatonin concentrations were higher during the night than during the day in both dippers and non-dippers. When patients were divided into dippers and non-dippers on the basis of mean arterial or diastolic BP a lower ratio of night/day concentration was determined in non-dippers than in dippers. Our study showed a blunted night/day difference in plasma melatonin concentrations in hypertensive patients with the non-dipping profile in diastolic BP indicating disturbances in the circadian system of these patients. [Copyright &y& Elsevier]

Optical modelling is used to investigate effects of light scattering in amorphous silicon and microcrystalline silicon solar cells. The role of enhanced haze parameter and different angular distribution function of scattered light is analyzed. Results of optical simulation show that enhanced haze parameter compared to that of Asahi U-type SnO2:F does not improve external quantum efficiency and short-circuit current density of amorphous silicon solar cell significantly, whereas for microcrystalline silicon solar cell the improvement is larger. Angular distribution function affects the external quantum efficiency and the short-circuit current density significantly. [Copyright &y& Elsevier]

Current hydrogenated amorphous and micro-crystalline silicon solar cells use textured substrates for enhancing the light absorption and (graded) buffer layers in order to improve the overall performance of the cells. The resulting solar cell structures are very complex and for understanding the role of these layers and for further optimization of the solar cell structures computer modeling is a useful tool. Integrated electrical and optical modeling was used to optimize hydrogenated amorphous silicon-germanium (a-SiGe:H) solar cells. Using simulations various mobility gap profiling schemes of the intrinsic a-SiGe:H layer were analyzed. On the basis of these simulations a new mobility gap profile (modified V type profile) for the intrinsic layer of a-SiGe:H solar cells is proposed. [Copyright &y& Elsevier]

During assembly of resuperheaters in a modernized power unit numerous cracks have occurred in 44.5 (OD) mm×4 mm TIG welded tube joints made of dissimilar martensitic steels X20CrMoV 12.1 and T91. All cracks were located in the HAZ of the X20 steel. The failure investigation covered metallographic examination and Vickers hardness measurements of test pieces cut out from the damaged resuperheaters. In the cracked specimens very high Vickers hardness was measured (up to 549 HV5) in the X20 steel HAZ with the presence of martensite. The not cracked welded joints were of lower hardness and martensite was partly tempered. By comparison of the maximum hardness of the tested specimens with those ones measured on specially shop welded joints after heat treatment at different temperatures and also left without heat treatment, it was found that the X20–T91 tube joints at the failed resuperheaters have not reached the required soaking temperature of 760 °C. Due to resistance heat treatment of the welded tube joints, grouped in bundles, their soaking temperatures were in the range between 550 °C and 680 °C and the cracked joints have not been tempered at all. After cutting out the defective joints new X20–T91 tubes have been welded and heat treated one by one. Vickers hardness measured on test samples of repair joints testifies the properly performed heat treatment. [Copyright &y& Elsevier]

Experimental investigation combined with computer modeling is used for analysis of light scattering process in hydrogenated amorphous silicon (a-Si:H) solar cells deposited on textured glass/ZnO:Al substrates. Descriptive scattering parameters—haze and angular distribution functions (ADFs)—for the textured ZnO:Al films with different surface roughness are determined. The haze parameters of all internal interfaces in the a-Si:H solar cells are calculated using equations of scalar scattering theory calibrated on the measurements of the substrates. The ADFs determined for the substrates are modified and applied to the internal interfaces. The scattering parameters are incorporated in our optical model and used to simulate the effect of the ZnO:Al surface roughness on the quantum efficiency (QE) of the solar cells. The simulations reproduce the measured QE of all solar cells with different roughness of the substrate very well. [Copyright &y& Elsevier]

The main features of a recently developed semi-coherent optical model for a-Si:H thin film solar cells with rough interfaces are presented. In contrast to the previous optical models, the model takes into account also the interference fringes observed in measured wavelength-dependent characteristics of a-Si:H solar cells. The simulations of the quantum efficiencies of the cells with different intrinsic a-Si:H layer thicknesses and interface root mean square (rms) roughness of 40 nm are shown and compared with the measured data. [Copyright &y& Elsevier]

Introduction: Men and women are thought to regulate their smoking differently and to differ in their susceptibility to nicotine addiction. Methods and Materials: Various measures of smoke exposure were compared between 400 current regular tobacco-dependent (DSM-IV) male and female light (1-15 cigarettes per day) and heavy (>15 cigarettes per day) smokers. Between 2 and 8 PM, blood was collected for nicotine and cotinine analysis, and breath carbon monoxide (CO) was measured. Individuals with genetic variants of the CYP2A6 gene were removed from analysis (n = 25). Results: No significant difference was found in the number of cigarettes per day or CO levels between the sexes. However, females had significantly lower nicotine levels than males (16.9 ± 0.6 vs. 21.1 ± 0.07, p < 0.01). This is only partly explained by the fact that females smoked lower nicotine-containing cigarettes. Female heavy smokers demonstrated higher -log nicotine/CO values (a representation of cost of smoking) compared with male heavy smokers (0.1 ± 0.02 vs. 0.02 ± 0.01 mg/L ppm, p < 0.05). Conclusions: Thus, gender differences appear to exist in smoking behaviors, nicotine sensitivity, and nicotine requirements. These differences are expected to contribute to gender differences in health risks and cancers associated with smoking. [ABSTRACT FROM AUTHOR]

In this work we investigated the stability of a-Si:H films under illumination and following recovery in darkness at different temperatures. The a-Si:H films were fabricated with 55 kHz PECVD and with conventional rf 13.56 MHz PECVD. We measured the steady-state photocurrent and the dark-current after switching off the light source as a function of time. We observed photocurrent degradation and the following recovery of the dark current. The kinetics of the photocurrent degradation as well as the dark-current recovery demonstrated stretched-exponential behavior. The results of these straightforward measurements in combination with computer simulation were used to determine the effect of light-induced degradation and thermal recovery on the density of states distribution in the band gap of a-Si:H. We have found that the photocurrent degradation and the corresponding increase in the total defect concentration have different kinetics. The different kinetics were also determined for the dark-current recovery and the corresponding decrease in the total defect concentration. The results point out that slow and fast types of defects in a-Si:H films control the kinetics of light-induced changes of the defect distribution in the band gap. A model is proposed that relates the origin of the fast and slow metastable defects with the distribution of Si-Si bond lengths. [ABSTRACT FROM AUTHOR]

A concept of a modulated one-dimensional photonic-crystal (PC) structure is introduced as a back reflector for thin-film solar cells. The structure comprises two PC parts, each consisting of layers of different thicknesses. Using layers of amorphous silicon and amorphous silicon nitride a reflectance close to 100% is achieved over a broad wavelength region (700–1300 nm). Based on this concept, a back reflector was designed for thin-film microcrystalline silicon solar cells, using n-doped amorphous silicon and ZnO:Al. Simulations show that the short-circuit current of the cell with a modulated PC back reflector closely resembles that of a cell with an ideal reflector. [ABSTRACT FROM AUTHOR]

Device modeling of p-i-n junction amorphous silicon solar cells has been carried out using the amorphous semiconductor analysis (ASA) simulation programme. The aim of the study was to explain the role of a buffer layer in between the p- and i-layers of the p-i-n solar cell on the external parameters such as dark current density and open circuit voltage. Investigations based on the simulation of dark I-V characteristics revealed that as the buffer layer thickness increases the dark current for a given voltage decreases. [ABSTRACT FROM AUTHOR]

Solar photovoltaic (PV) energy is variable. The output power can change considerably in a matter of minutes, imposing challenges on the control of systems connected downstream. The power from these systems can be smoothed using electric storage, potentially increasing the system cost. An alternative is to deliberately curtail the power before it starts to change. This strategy relies on ultra-short-term forecasting to determine the curtailment point. Unfortunately, forecasting is prone to errors and high uncertainty even in the very short-term, leading to control errors. We propose an active power curtailment control strategy for a stand-alone solar photovoltaic system powering an electrolyzer. Our work's novelty relies on the controller's ability to deal with large forecasting errors and high uncertainty, combining artificial intelligence for predicting the power ramps and fuzzy logic to account for imperfect prediction. We validated our approach using a hardware emulator of the photovoltaic system, power converter and electrolyzer. Under clear sky conditions, the curtailment results in unnecessary energy loss, while under variable irradiance, the controller successfully smooths the power ramps within 10% of the PV system's nominal power. Although our approach was designed for a stand-alone system, its concept can be directly applied to grid-connected systems as well. • Application of forecasting for power smoothing. • Uncertainty-based prediction. • Control decision considering the uncertainty. • Power ramp smoothing without electric storage. [ABSTRACT FROM AUTHOR]

Wstęp. Leczenie chirurgiczne ciągle pozostaje najistotniejszą częścią skojarzonego leczenia chorych na raka odbytnicy. Powikłania tego leczenia, a w szczególności nieszczelność zespolenia jelitowego po przedniej resekcji odbytnicy, stanowią istotny problem kliniczny. Cel. Celem pracy jest retrospektywna analiza czynników klinicznych znanych przed zabiegiem operacyjnym, mogących mieć wpływ na wystąpienie powikłań. Materiał i metody. Analizie poddano 418 kolejnych chorych operowanych z powodu raka odbytnicy (246 mężczyzn i 172 kobiety) w okresie od lipca 2013 do grudnia 2016. Wykonano 257 resekcji przednich, 135 resekcji brzuszno-kroczowych oraz 26 resekcji sposobem Hartmanna. Czynniki predykcyjne wystąpienia powikłań poddano analizie regresji logistycznej. Wyniki. W całej badanej grupie chorych powikłania pooperacyjne wystąpiły w 24,6% przypadków, w tym powikłania w stopniu 3 lub wyższym wg Claviena w 10,5% przypadków. Śmiertelność okołooperacyjna wyniosła 0,5%. W grupie chorych po przedniej resekcji odbytnicy w 29 (11,3%) przypadkach stwierdzono nieszczelność zespolenia jelitowego, w tym 18 nieszczelności wczesnych i 11 późnych. Analipowikłań zgodnie z klasyfikacją Claviena wykazała, że znamienny wpływ na ryzyko wystąpienia powikłań w całej grupie chorych miały: choroba niedokrwienna serca, stosunek neutrofilów do limfocytów (NLR) > 5 oraz prognostic nutritional index. Statystycznie znamiennymi czynnikami ryzyka wystąpienia nieszczelności wczesnych okazały się przedoperacyjny NLR > 5 oraz liczba płytek krwi obwodowej, natomiast w przypadku nieszczelności późnych - towarzysząca choroba niedokrwienna mięśnia sercowego. Wnioski. W całej grupie chorych stwierdziliśmy niski odsetek ciężkich powikłań i zgonów pooperacyjnych. W badanym materiale stwierdziliśmy odmienne czynniki ryzyka nieszczelności wczesnych i późnych, co wskazuje na ich odmienną etiologię. [ABSTRACT FROM AUTHOR]

A correction to the article "Thermal stability of TiO2, ZrO2, or HfO2 on Si(100) by photoelectron emission microscopy," by M.C. Zeman, C.C. Fulton, G. Lucovsky and R.J. Nemanich and W.-C. Yang.

Wstęp. Zabiegi miejscowego, endoskopowego wycięcia guzów odbytnicy zyskały popularność w ostatnich dwóch dekadach, jednakże liczba procedur przeprowadzanych rocznie w pojedynczych ośrodkach nie jest wysoka. Cel. Ocena wyników leczenia guzów dolnego odcinka odbytnicy metodą przezodbytowej endoskopowej mikrochirurgii (TEM). Materiał i metody. 62 chorych leczonych w technice TEM: 29 (46%) z powodu gruczolakoraka: 28 w stopniu zaawansowania cT1N0M0 (grupa 1), 18 (28,6%) z powodu zmian łagodnych, 12 (19%) z powodu nowotworów neuroendokrynnych, 3 z powodu innych guzów. Ponadto wyodrębniono grupę 40 chorych na gruczolakoraka cT1-T2N0M0 operowanych brzusznymi metodami klasycznymi (grupa 2). Analiza statystyczna wykonana została w programie IBM SPSS 20 PL. Wyniki. Średni czas operacji wynosił 100 minut (mediana 82 minut) i nie różnił się między grupami (p = 0,185), mimo różnicy w wielkości operowanych zmian (p = 0,00). Nie wykazano istotnych statystycznie różnic w czasie trwania operacji w poszczególnych latach (p = 0,92). Wolne marginesy wycięcia uzyskano u 59 chorych (95,2%). Powikłania pooperacyjne wystąpiły u 2 osób (3% chorych). Nawrót odnotowano w 6 przypadkach (9,6%). Czas zabiegów brzusznych był dłuższy (p = 0,01). Operacje klasyczne wiążą się z wyższym ryzykiem powikłań pooperacyjnych i dłuższym pobytem chorego na oddziale (p = 0,004; p = 0,00). Nie odnotowano istotnych różnic w częstości nawrotów i rozsiewu (p = 0,59; p = 0,95). Wnioski. Dla wyselekcjonowanych chorych technika TEM stanowi bezpieczną, metodę leczenia operacyjnego. Wyniki potwierdzają skuteczność leczenia miejscowego raka odbytnicy o zaawansowaniu T1 bez dodatkowych czynników ryzyka. [ABSTRACT FROM AUTHOR]

Microcrystalline silicon (μc-Si:H) is a promising material for application in multijunction thin-film solar cells. A detailed analysis of the optoelectronic properties is impeded by its complex microstructural properties. In this work we will focus on determining the mobility gap of μc-Si:H material. Commonly a value of 1.1 eV is found, similar to the bandgap of crystalline silicon. However, in other studies mobility gap values have been reported to be in the range of 1.48–1.59 eV, depending on crystalline volume fraction. Indeed, for the accurate modeling of μc-Si:H solar cells, it is paramount that key parameters such as the mobility gap are accurately determined. A method is presented to determine the mobility gap of the intrinsic layer in a p-i-n device from the voltage-dependent dark current activation energy. We thus determined a value of 1.19 eV for the mobility gap of the intrinsic layer of an μc-Si:H p-i-n device. We analyze the obtained results in detail through numerical simulations of the μc-Si:H p-i-n device. The applicability of the method for other than the investigated devices is discussed with the aid of numerical simulations. [ABSTRACT FROM AUTHOR]

Staphylococcus sciuri is a bacterial pathogen associated with infections in animals and humans, and represents a reservoir for the mecA gene encoding methicillin-resistance in staphylococci. No S. sciuri siphophages were known. Here the identification and characterization of two temperate S. sciuri phages from the Siphoviridae family designated ϕ575 and ϕ879 are presented. The phages have icosahedral heads and flexible noncontractile tails that end with a tail spike. The genomes of the phages are 42,160 and 41,448 bp long and encode 58 and 55 ORFs, respectively, arranged in functional modules. Their head-tail morphogenesis modules are similar to those of Staphylococcus aureus ϕ13-like serogroup F phages, suggesting their common evolutionary origin. The genome of phage ϕ575 harbours genes for staphylokinase and phospholipase that might enhance the virulence of the bacterial hosts. In addition both of the phages package a homologue of the mecA gene, which is a requirement for its lateral transfer. Phage ϕ879 transduces tetracycline and aminoglycoside pSTS7-like resistance plasmids from its host to other S. sciuri strains and to S. aureus. Furthermore, both of the phages efficiently adsorb to numerous staphylococcal species, indicating that they may contribute to interspecies horizontal gene transfer. [ABSTRACT FROM AUTHOR]

The article presents the main topics in the development of a parametric model to analyze individual retrospective clinical data of cementless hip prosthesis cases. The long term goal is to develop a predictive tool for cementless Total Hip Arthroplasty outcome. The method used to obtain a rapidly and optimal bony integration of a prosthesis a complete and close contact between the endosteal bone and implant surface is described. It was found that the area against rotation seems to be the most critical to the long term functionality of a cementless hip prosthesis.

Integration of photovoltaics (PV) into the urban environment will play a major role in the energy transition. However, installing PV systems on building roofs can be challenging, particularly for monumental buildings with strict architectural and social value restrictions. Assessing roof surface visibility is, therefore, key to finding as much permitted roof surface area as possible that may be used for PV installation. In this study, a GIS-based large-scale visibility assessment tool is developed that can assist in evaluating roof visibility, using LiDAR, road networks, and cadastral data as inputs. The tool delivers multi-level outputs, including maps of roof binary visibility, roof visual amplitude, roof PV system layout, roof PV system AC yield, and roof PV module visibility. After optimization, an average speed of 0.12 s/ m 2 is achieved. For each roof surface, an additional sensitivity analysis has been conducted. This step determines the optimal values for two visibility analysis parameters: assessment range and observer spacing, balancing the computational demand and result accuracy. Application of this workflow to the monumental buildings on the TU Delft campus revealed that approximately 2.68 GWh/year of electricity could be harvested from imperceptible PV modules, while an additional 0.42 GWh/year of energy is attributed to PV modules with medium visibility, and 0.37 GWh/year of energy is associated with PV modules with high visibility. This modeling workflow supports the multi-criteria decision-making process for urban roof PV planning. • A GIS-based large-scale visibility assessment tool has been developed. • It uses LiDAR, road networks, and cadastral data as inputs. • It delivers annual AC yield of roof PV systems with low, medium, and high visibility. • This tool has been implemented on the monumental buildings on the TUD campus. • It reports annual AC yield of 2.68, 0.42, and 0.37 GWh/year for each visibility group. [ABSTRACT FROM AUTHOR]

Carrier-selective passivating contacts have been demonstrated to be crucial to reach the practical efficiency limit of single junction, crystalline silicon (c-Si) based solar cells. Yet, the electrical transport losses affecting the collection of photogenerated carriers remain to be addressed. To this aim, different methodologies and characterization techniques are currently used. In this contribution, we propose the concept of shell as a new terminology to describe carrier-selective passivating contacts. Then, we present a novel characterization methodology using transfer length method (TLM) measurement under variable illumination to investigate the charge-carrier transport in amorphous/crystalline silicon heterojunction (SHJ) n-type contact stacks. We use technology computer-aided design simulation to model a TLM structure and to identify the physical phenomena and the key parameters affecting the contact resistivity (ρ c) and the charge carrier accumulation of such contact stacks. Then, the simulation results are compared with experimental data by performing variable-illumination TLM measurements of actual SHJ n-type contact stacks. Specifically, we demonstrate that illumination has a strong impact on the measured ρ c value, highlighting the importance of measuring ρ c under maximum power point conditions for a relevant characterization of solar cell transport losses. In addition, we investigate the dependence of ρ c to a change in the injected carrier density within the c-Si bulk to compare the illumination responses of different SHJ n-type contact stacks. In the quest for maximal efficiency, this method may insightfully complete other characterization techniques to further understand and study the electrical transport in solar cells. [ABSTRACT FROM AUTHOR]

Objective: To describe a case of refeeding syndrome in a patient after two months of diet with significant restriction or even absence of saccharides and to point out the threat of severe diets and return to common diet. Design: Case report. Setting: General Teaching Hospital Prague. Material and Methods: Description of a case including laboratory results with comments. Results: The work shows severe metabolic changes (hypophosphatemia, hypokalemia, elevation of transaminases and of creatine kinase) with clinical consequences after saccharide intake followed by their two-months significant restriction. Conclusion: Refeeding syndrome represents a potential problem not only in patients after operations, patients with tumours and in the elderly, but may threat also after enormous changes of the diet. [ABSTRACT FROM AUTHOR]

Barium di-silicide (BaSi2) is a very promising absorber material for high-efficiency thin-film solar cells, due to its suitable bandgap, high light absorption coefficient, and long minority-carrier lifetime. In this study, we compare the nanostructure, layer composition, and point defects of BaSi2 thin films deposited by Radio Frequency (RF) sputtering, Thermal Evaporation (TE), and Molecular Beam Epitaxy (MBE), using Doppler Broadening Positron Annihilation Spectroscopy (DB-PAS) depth profiling, Raman spectroscopy, and x-ray diffraction. Our DB-PAS study on thermally annealed RF-sputter deposited and on TE-deposited BaSi2 layers, in a comparison with high quality BaSi2 films produced by MBE, points to the presence of vacancy-oxygen complexes and Si or Ba mono-vacancies, respectively, in the (poly)crystalline BaSi2 films. The degree of near-surface oxidation increases, going from MBE and TE to the industrially applicable RF-sputtered deposition synthesis. The use of a-Si capping layers on the thermally annealed RF-sputtered BaSi2 films leads to a clear reduction in sub-surface oxidation and improves the quality of the BaSi2 films, as judged from DB-PAS. [ABSTRACT FROM AUTHOR]

Abstract: A circadian rhythm is documented in duodenal melatonin in rats, peaking 16.8 hours after light onset. This component is more readily detected after log10-transformation of the data. It differs between male and female rats, females having a larger circadian amplitude and an earlier acrophase. The circadian rhythm in duodenal melatonin is also found to lead that of pineal melatonin. The results are qualified by the presence at the start of mapping of the second extremum of a double magnetic storm. [Copyright &y& Elsevier]

Abstract: A circadian rhythm is documented for plasma, pineal, and hypothalamic melatonin of male and female rats kept on staggered lighting regimens. Log[_10]-transformation of the data usually normalizes, when need be, the distribution of residuals from the 24-hour cosine curve fits. A tentative circadian acrophase chart is presented that shows a lead in circadian acrophase of duodenal over pineal melatonin. The use of antiphasic lighting regimens facilitates circadian studies that can be carried out for several days, thereby allowing the assessment of infradian components such as a circasemiseptan variation in hypothalamic melatonin documented herein. The results are qualified by the presence of a second extremum of a double magnetic storm at the start of mapping. [Copyright &y& Elsevier]

This paper investigates the possibility of charging battery electric vehicles at workplace in Netherlands using solar energy. Data from the Dutch Meteorological Institute is used to determine the optimal orientation of PV panels for maximum energy yield in the Netherlands. The seasonal and diurnal variation in solar insolation is analyzed to determine the energy availability for EV charging and the necessity for grid connection. Due to relatively low solar insolation in Netherlands, it has been determined that the power rating of the PV array can be oversized by 30% with respect to power rating of the converter. Various dynamic EV charging profiles are compared with an aim to minimize the grid dependency and to maximize the usage of solar power to directly charge the EV. Two scenarios are considered – one where the EVs have to be charged only on weekdays and the second case where EV have to be charged all 7 days/week. A priority mechanism is proposed to facilitate the charging of multiple EV from a single EV–PV charger. The feasibility of integrating a local storage to the EV–PV charger to make it grid independent is evaluated. The optimal storage size that reduces the grid dependency by 25% is evaluated. [ABSTRACT FROM AUTHOR]

1. The light regime during incubation can influence embryonic and post-embryonic life and its effects can be mediated by rhythmic melatonin production in the embryonic pineal gland. 2. This study explored whether the incubation of chick embryos under red or blue monochromatic light, which induces maximum and minimum melatonin production, respectively, can influence the development and reactivity of the immune system in chicks. 3. In hatchlings, basal expression of immune genes (AvBD-1, PSEN-1, and IL-6) was evaluated in the duodenum using real-time PCR. The expression of these genes was measured weekly for three weeks after hatching, 3 h after intraperitoneal lipopolysaccharide (LPS) injection. At these times, the heterophil/lymphocyte ratio (He/Ly) was evaluated on blood smears, plasma immunoglobulin Y (IgY) concentrations by ELISA and IL-6 gene expression in the spleen by real-time PCR were determined. 4. During development, the He/Ly ratio and plasma IgY concentration were not significantly influenced by the light quality during incubation. Red light increased gene expression of AvBD-1 in hatchlings and IL-6 in two-week-old chickens compared to birds incubated under blue light. The expression of IL-6 after LPS stimulation increased in an age-dependent manner, both in the duodenum and the spleen, reflecting the maturation of the immune system. 5. The results suggested that red light may increase the local immune response in the gut immediately after hatching, but this effect was not apparent during later development. [ABSTRACT FROM AUTHOR]

Abstract: The performance of hydrogenated amorphous silicon solar cells (a-Si:H) is limited due to the relatively high defect concentration in the intrinsic layer, leading to high recombination rates. The dark current-voltage (JV) characteristics of these cells are mainly determined by recombination processes. Several parameters influence these processes: the density-of-states distribution in the mobility gap, the spatial distribution of recombination centers, and the recombination efficacy. As a result the ideality factor is non-integer and varies with voltage. The temperature dependence of the dark JV curves reveals the bias dependent activation energy, a measure for the mobility gap, and the temperature dependence of the recombination efficacy. In this contribution we present results of accurate dark JV measurements at different temperatures and a comparison to computer simulations. By analyzing the temperature dependence we study the influence of the recombination efficacy on the recombination rate and determine where in the device recombination is most effective. Simulations show that the shape of the recombination efficacy curve depends on the cross-section ratio for electron and hole trapping. Whereas the recombination rate is mainly determined by the local defect density in the device and controls the JV characteristic, the recombination efficacy controls the temperature dependence. [Copyright &y& Elsevier]