Outer Layer Thickness Research Articles

Efficient and high-bifacial CdTe-based solar cell enabled by functional designed dielectric/metal/dielectric transparent top contact via light management engineering

Transparent, anti-reflective, and electrically compatible contact designs that can effectively be implemented in bifacial applications is attributed as a crucial criterion validated by effective techniques to improve photon harvesting and energy efficiency in high-efficiency CdTe solar cells (SC). As an ITO alternative for CdTe SCs, MoO3/Au/WO3 dielectric/metal/dielectric (DMD) transparent contact is proposed as an effective design in the current study. By integrating the MoO3/Au/WO3 transparent contact into the bifacial CdTe SC, the optimum structural parameters are determined for both top and bottom illumination through light management engineering. An optimal situation is constructed based on the photocurrent density derived from the optical characteristics calculated with the Transfer Matrix Method. The fabricated bifacial CdTe SC with optimal MoO3/Au/WO3 top contact is investigated by comparing with monofacial convectional thick Au top contact and bifacial ITO top contact. In the case of 10 nm metal and 34 nm outer dielectric layer thicknesses (dAu and dWO3, respectively), highest photocurrent density is obtained for both top and top illumination. It has been reported that dAu should be less than 40 nm as the limit of the bifacial operating condition. For the best reflectivity, the following values of dAu = 12 nm and dWO3 = 2540 nm must be taken. For lower and upper illumination, Jsc increases from 17.06 mA/cm2 to 19.91 mA/cm2, and from 5.91 mA/cm2 to 9.27 mA/cm2, respectively. Furthermore, the power conversion efficiency has increased from 9.65% to 10.69% and 3.43 to 4.96 for bottom and top illumination, respectively. Hence, the photon harvesting in CdTe SC with MoO3/Au/WO3 transparent top contact is improved. This superior performance provides a bifaciality from 0.36 to 0.46 by 27.9%. As per the authors’ knowledge, for the first time in the literature, this report introduces the bifacial CdS/CdTe heterojunction-based SC with only MoO3/Au/WO3 DMD transparent top contact via light management engineering. It includes a new methodology and detailed feedback for the design and manufacture of optoelectronic devices that are alternative to ITO due to the bifacial working conditions, that require innovative, anti-reflective and efficient new contact systems, which have been improved with functionally designed DMD integration.

Effect of Microstructural Evolution on Mechanical Properties and Fracture Modes of AlSi10Mg Blocks Fabricated by Selective Laser Melting after Stress Relief Annealing

AlSi10Mg parts fabricated by selective laser melting (SLM) are frequently reported to have heterogeneous microstructures. How this affects the mechanical properties of SLM parts still requires further study. Herein, AlSi10Mg blocks with simple cuboid shape are printed and annealed at 300 °C. Their microstructure changes significantly from edge to center and from top to bottom. Low‐temperature annealing is not sufficient to eliminate structural heterogeneity. Before annealing, the Si‐rich phase is fine and mainly exists in the form of a eutectic network. The as‐printed blocks have high tensile strength, and the fracture surface exhibits a mix of transcellular pits and pores. After annealing, the network structure is completely broken or disappeared in most locations in the blocks. The Si‐rich phase is significantly coarsened and even segregated locally along the melt pool boundaries. Yield strength is reduced by 25%–47%, but elongation values are doubled. Tensile samples are fractured by an along‐the‐pool boundary fracture mode along the boundary. Micropores formed during the printing process are aggregated in the about 200 μm thick outer surface layer of the block. They also have a significant effect on the local elongation both before and after annealing.

Rebuilding the foundation of late Paleozoic pinnid bivalve study (family Pinnidae)

AbstractThe early geologic history of family Pinnidae, a diverse and abundant component of mud-dominated shallow marine environments of the late Paleozoic, is obscured by ill-defined genus and species concepts. Mistakes in descriptions and reconstructions have provided a basis for suggestions that older taxa in the family differ from younger taxa and may not belong in family Pinnidae. This report provides improved documentation that removes the basis for the concept of divergence. Late Paleozoic genera and species have definite pinnid bivalve characters, including a dorsomarginal fold that holds the ligament, a thick outer columnar prismatic shell layer, and an equivalved, triangular shell, all of which provide evidence for confident assignment of the genus to family Pinnidae. The suggested synonymy of Aviculopinna with Pteronites is invalid, and genus Aviculopinna is limited to occurrence in Permian strata. The two genera belong in different families. A neotype is designated for genus Aviculopinna type species Aviculopinna pinnaeformis Geinitz from Gera, Germany, and a lectotype for Aviculopinna neukirchensis Langenhan from Nowy Kościół, Poland. Inferences on the life habits of Aviculopinna based on its occurrence in Poland are presented. An evaluation of the subterminal beak versus terminal beak concept in pinnids is presented and conclusion presented that there are few data available to support the concept or to test it. In its present form, the concept has no utility in the study of pinnid bivalves.

Effect of Zn addition on the corrosion behaviours of as-cast BCC Mg-11Li based alloys in NaCl solution

Effect of Zn on the corrosion behaviours of Mg-11Li-xZn (x = 0, 1, 3, 6; termed as L11, LZ111, LZ113, LZ116) alloys in 0.1 M NaCl solution has been investigated. The results reveal that corrosion resistance of four alloys increases following the order LZ116 < LZ113 ≈ L11 < LZ111. Besides, filiform-like corrosion occurs at early corrosion stage for the four alloys, while additional pitting corrosion preferentially emerges in the L11, LZ113 and LZ116 alloys with immersion time. The small alloying Zn can reduce corrosion rate of Mg-11Li alloys, and excess Zn will accelerate the corrosion due to the existence of micro-galvanic effect between second phase and matrix. Regarding of the surface film, double layers of considerable thick outer layer and inner layer can be observed on the top of L11 and LZ111. Nevertheless, small alloying Zn is prone to modify the surface film and contributes to the high corrosion resistance of LZ111 alloy, while high Zn concentration results in the rapid corrosion damage of surface films on the LZ113 and LZ116 alloys and further elevate corrosion rate.

The Effect of FDM Process Parameters on the Compressive Property of ABS Prints

Most 3D-printed FDM items are not solid-printed because printing solids requires a large amount of material and a relatively long printing time, both of which result in higher printing costs. Most items are printed with a hard shell and proper infill density to optimize the printing process. The shell width, the filling density, the infill pattern, and the thickness of the layer all play an important role in the quality of the printed items. This new work aims to characterize the FDM process to apply this technology in printing parts to withstand stresses by focusing on the most important process parameters that contribute to improving the bearing of parts when exposed to compression. For this purpose, the effects of four main parameters of the FDM, which are: infill density, outer shell width, infill pattern, and layer thickness, with different levels of each parameter, were investigated, and the effect of each of these parameters on the compressive property of the printed parts was also examined. The Taguchi method was used to design the experiments so that all parameter levels were tested in the fewest possible number of tests. The signal-to-noise ratio (S/N) was also used to clarify and measure the effect of the process variables on the compressive property. The compression test was adopted as the basis for analyzing test results, which confirmed that the effect of the infill density on the compressive resistance can be classified at a strong level (rank 1), and that of the outer shell width on the compressive resistance can be classified at a level ranging from medium to strong (rank 2), while that of the infill pattern on the compressive resistance can be classified at a range from weak to medium level (rank 3), and the effect of the layer thickness on the compressive resistance can be classified as weak (rank 4). This work provides an opportunity to improve the functionality of the multipurpose FDM process, which can be used to reduce the number of raw materials required, efficiently shorten printing times, and enhance the compressive properties to meet the needs of FDM print design better.

Effect of expanded polytetrafluoroethylene thickness on paclitaxel release and edge stenosis in stent graft.

Stent grafts have been widely used to treat lower extremity arterial stenosis or occlusion. However, there are major issues with edge stenosis and loss of patency over time. Paclitaxel-coated stent grafts have been proven to be effective in preventing edge stenosis, but the insufficient amounts of paclitaxel released may limit the effectiveness of drug-eluting stent grafts. In this study, we examined whether paclitaxel-coated expanded polytetrafluoroethylene (ePTFE) stent graft thickness influences paclitaxel release properties and inhibits edge stenosis. Low-, medium-, and high-thickness paclitaxel-coated stent grafts were prepared by varying the thickness of inner and outer ePTFE layers. Surface morphologies of the stent grafts were analyzed using a scanning electron microscope. The stent grafts were then implanted in the iliac arteries of 20 healthy swine. Twelve pigs were used to assess edge stenosis, and digital subtraction angiography was performed at day 30 (n = 4), 90 (n = 4), and 180 (n = 4). Histological evaluation of the treated arteries was also performed. Eight pigs were used for pharmacokinetic analysis, and the treated arteries were obtained at day 1 (n = 2), 30 (n = 2), 90 (n = 2) and 180 (n = 2). Scanning electron microscopy confirmed that the mean pore size of the stent grafts decreased with increasing thickness. The results of angiographic and histological evaluation demonstrated that low-thickness ePTFE-stent grafts resulted in edge stenosis and apparent intimal hyperplasia at 180 days, whereas for medium-thickness ePTFE-stent grafts, no obvious edge stenosis and intimal hyperplasia was noted in the similar time period. The results of pharmacokinetic evaluation showed that at 180 days, the paclitaxel concentration of treated arteries of the medium group was 36 ± 53 ng/g, while concentrations in the low group was not detectable. Stent grafts with increased ePTFE thickness appear to allow for more delayed release of paclitaxel compared to low-thickness ePTFEs.

Cryo-EM structures of prion protein filaments from Gerstmann–Sträussler–Scheinker disease

Prion protein (PrP) aggregation and formation of PrP amyloid (APrP) are central events in the pathogenesis of prion diseases. In the dominantly inherited prion protein amyloidosis known as Gerstmann–Sträussler–Scheinker (GSS) disease, plaques made of PrP amyloid are present throughout the brain. The c.593t > c mutation in the prion protein gene (PRNP) results in a phenylalanine to serine amino acid substitution at PrP residue 198 (F198S) and causes the most severe amyloidosis among GSS variants. It has been shown that neurodegeneration in this disease is associated with the presence of extracellular APrP plaques and neuronal intracytoplasmic Tau inclusions, that have been shown to contain paired helical filaments identical to those found in Alzheimer disease. Using cryogenic electron microscopy (cryo-EM), we determined for the first time the structures of filaments of human APrP, isolated post-mortem from the brain of two symptomatic PRNP F198S mutation carriers. We report that in GSS (F198S) APrP filaments are composed of dimeric, trimeric and tetrameric left-handed protofilaments with their protomers sharing a common protein fold. The protomers in the cross-β spines consist of 62 amino acids and span from glycine 80 to phenylalanine 141, adopting a previously unseen spiral fold with a thicker outer layer and a thinner inner layer. Each protomer comprises nine short β-strands, with the β1 and β8 strands, as well as the β4 and β9 strands, forming a steric zipper. The data obtained by cryo-EM provide insights into the structural complexity of the PrP filament in a dominantly inherited human PrP amyloidosis. The novel findings highlight the urgency of extending our knowledge of the filaments' structures that may underlie distinct clinical and pathologic phenotypes of human neurodegenerative diseases.

Design and fabrication of a tapered fiber bundle for a pump combiner with a uniform splicing region

A process of fabricating tapered fiber bundle (TFB) consisting of a set of input pump fibers, stacked inside a low-OH silica capillary, has been optimized to combine multiple multimode pump powers into different output fibers having cladding diameters of 400, 250, and 125 µm. Instead of individual input and output fiber processing, here pump combiner fabrication is based on the processing of the TFB to match its diameter with the output fiber to eliminate any perturbation in light guidance. Fabrication of the TFB includes multiple fusing steps and tapering with brightness conservation, followed by reduction of the outer silica layer through chemical etching to obtain the desired outer diameter. To reduce pump power leakage, the optimum fluorine cladding layer thickness outside the pump fiber cores and outer silica layer thickness have been estimated through numerical simulations using a finite element solver. The influence of fabrication parameters such as interstitial gaps between the input pump fibers, taper ratio, fluorine cladding, outer silica layer thickness, and non-uniformity of splicing region has been characterized in terms of transmission efficiency per port, as well as cumulative power handling along with the operating temperature at maximum power.

Comparison of Each Retinal Layer Thicknesses between Eyes with Central Retinal Vein Occlusion and Normal Contralateral Eyes.

PurposeTo evaluate the difference in each retinal layer thickness in central retinal vein occlusion (CRVO) with resolved macular edema after intravitreal antivascular endothelial growth factor injection and normal contralateral eyes..MethodsPatients with ischemic and nonischemic CRVO whose macular edema resolved after intravitreal antivascular endothelial growth factor injections and did not recur for at least 6 months, and a normal contralateral eye were enrolled. Each retinal layer thickness between CRVO and normal contralateral eyes was compared according to Early Treatment Diabetic Retinopathy Study subfields using spectral domain optical coherence tomography.ResultsThe thicknesses of outer nuclear layer, photoreceptor layer, and retinal pigment epithelium in central ring, ganglion cell layer, inner plexiform layer, outer nuclear layer, and photoreceptor layer in the inner ring, and ganglion cell layer in the outer ring of CRVO eyes were significantly thinner than those of normal contralateral eyes (all p < 0.05). Whereas, inner nuclear layer and outer plexiform layer thicknesses in central ring of CRVO eyes were 23.86 ± 8.8 and 25.76 ± 7.6 μm, respectively, which was significantly thicker than those of normal contralateral eyes (19.52 ± 7.7 and 22.76 ± 6.5 μm; p = 0.019 and p = 0.043, respectively). Additionally, the mean best-corrected visual acuity of CRVO eyes were significantly correlated with photoreceptor layer thickness in central ring (p = 0.005).ConclusionsIn CRVO eyes with resolved macular edema, the outer retinal layers were thinner as well as inner retinal layers, whereas inner plexiform layer and outer nuclear layer were thicker than normal fellow eyes. Additionally, photoreceptor layer thickness in foveal area had a significant impact on visual acuity in CRVO.

Saffron extract attenuates Sofosbuvir-induced retinal neurodegeneration in albino rat.

Sofosbuvir is a novel drug candidate for the treatment of hepatitis C viral infection; however, vision loss is one of its growing adverse effects. Saffron is a natural biomolecule with a high antioxidant potential that has been efficiently used in some diseases caused by oxidative stress. This study evaluated Sofosbuvir's neurodegenerative effect on the retina of albino rat and examined the potential protective role of saffron aqueous extract. Twenty-one adult male albino rats were randomly divided into three groups: Control, Sofosbuvir-treated (41.1 mg/kg /day for 6 weeks), and Sofosbuvir + Saffron co-treated groups. Retinal specimens were biochemically analyzed for malondialdehyde (MDA), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) levels. In addition, light and transmission electron microscopic examination, as well as immunohistochemical staining for Caspase-3, COX-2, and GFAP were performed. Sofosbuvir treatment caused a significant increase in retinal MDA, IL-6, and TNF-α levels coupling with a significant decrease in retinal total antioxidant capacity level. Histopathological findings revealed disturbed retinal architecture, detached pigment epithelium, vacuolated photoreceptors, in addition to a significant decrease in the thicknesses of both outer and inner nuclear layers, and the number of ganglionic cells. Ultrastructural examination revealed extensive degenerative changes in all retinal layers. Caspase-3, COX-2, and GFAP immunohistochemical expressions were significantly increased. Meanwhile, concomitant treatment with Saffron significantly improved retinal redox status, inflammation, histological, and ultrastructural parameters. Saffron may protect the retina from the hazardous effects of Sofosbuvir. Saffron could be used as an adjuvant therapy to protect patients receiving Sofosbuvir from retinal damage.

Effect of thermal cycling on the corrosion behaviour of stainless steels and Ni-based alloys in molten salts under air and argon

High temperature corrosion of materials in molten salt is of great interest to renewable energy production industry, especially the wide application of molten salts as thermal energy transfer fluid and storage media in concentrated solar power plants. Molten nitrate salt is used in concentrated solar power plants due to its good balance of thermo-physical properties and cost. Storage tanks and heat transfer pipes are widely made of corrosion resistance alloys such as austenitic stainless steels and nickel-based alloys. The corrosion issues between salt-metal interface poses a critical challenge to safety operation and efficiency. In this study, the corrosion behaviour of stainless steels and Ni-based alloys; AISI 321 and 347, IN 625 and In 825, in Solar (nitrate) salts has been experimentally investigated under isothermal (at 565 °C) and thermal cycling (between 565 °C and 290 °C) conditions, and under air and argon atmosphere. Corrosion assessment of test alloys were achieved using gravimetric measurement in a simulated metal-salt environment in a furnace for 14 days. The micro-morphology and cross-sectional analysis of the corroded surfaces were investigated by a combination of scanning electron microscopy, energy dispersive X-ray diffraction techniques. Compared with isothermal condition in air, thermal cycling in air reduces the corrosion rate of test materials, the severity of corrosion attack and the thickness of corrosion product layers due to the lower exposure time at maximum temperature and cooling effect during thermal cycling, especially in stainless steels. Compared with thermal cycling in air, the obtained corrosion rate was observed to be higher for thermal cycling in argon due to the formation of thick and fragile outer layer of NaFeO2 that easily spalls during the corrosion process. A more resilient and potentially more protective inner layer of Cr2O3 and NiO are observed to form in stainless steels and nickel alloys respectively. The formation of intermediate layer of Fe2O3 is believed to offer some barrier to potential molten salt induced dissolution of the inner Cr and Ni-rich layer.

Histological Studies on Ageing Changes in the Retina of Buffaloes (Bubalus bubalis)

Background: Affections of eye are commonly encountered in all the species of animals. The age-related changes of the retina primarily cause loss of visual acuity as well as reduction of the visual field. Hence, the current study was carried out to establish basic data related to ageing changes in the retina of buffaloes. Methods: The study was conducted on 63 eye balls of locally available buffaloes of different breeds. These buffaloes were categorized into 3 groups i.e., group I (1-5 yrs), group II (6-10 yrs) and group III (11 yrs and above). The eyeballs were isolated and fixed with Davidson’s fluid. The paraffin sections were subjected for routine histological study. Result: The thickness of retinal pigment epithelium was increased from group I to III buffaloes from 6.06±0.18 to 8.44±0.32 and the quantity of melanin pigment was decreased with advancement of age. Rod and cone cells of the photoreceptor layer were tightly packed in young age, loosely arranged in old animals. The mean thickness (µm) of photoreceptors and outer nuclear layers together was decreased from 64.22±1.84 to 58.72±2.1 with age advancement. The displacement of nuclei from outer nuclear layer into outer plexiform layer was significantly decreased in old animals. The outer limiting membrane was continuous and uninterrupted throughout the life. The thickness of outer plexiform layer was increased with advancement of age from 8.78±0.58 to 10±0.51 due to enhancement of synaptic fibers density. As age advances the number and density of horizontal, bipolar and amacrine cells were decreased and also the mean thickness (µm) of this layer was decreased from 30.83±1.48 to 22.56±0.62 in the inner nuclear layer. The thickness of inner plexiform layer was increased from 42.44±2.23 to 45.39±0.81 with advancement of age due to increased cystoids spaces and thickening of retinal blood vessels. In ganglionic cell layer, the number of α-ganglion cells were more than the β-ganglion cells, their common number were decreased approximately from 16-20 cells/sq.mm to 7-10 cells/sq.mm, whereas the average size was increased from 4.72±0.49 to 15.83±0.83 with advancement of age. In aged buffaloes nerve fiber layer showed corpora amylacea and thickened blood vessels. The inner limiting membrane became thick and uninterrupted in old buffaloes. The total thickness (µm) of retina in group I, II and III buffaloes were 235.5±7.25, 184.33±3.64 and 201.05±5.15 respectively.

Abnormal foveal morphology in carriers of oculocutaneous albinism

Background/aimsTo investigate the foveal morphology in carriers of oculocutaneous albinism (OCA) using spectral domain optical coherence tomography (SD-OCT). A cross-sectional, observational study.MethodsHandheld SD-OCT (Envisu C2300) was used to acquire horizontal...

Structure evolution of nanodiamond aggregates: a SANS and USANS study.

Ultra-small-angle neutron scattering (USANS) and small-angle neutron scattering (SANS) measurements, covering length scales from micrometres to nanometres, were made to investigate the structure of nanodiamonds (NDs) and their suspensions. These nanodiamonds were produced by two different techniques, namely by the detonation method and by the laser ablation of a carbon-hydro-carbon mixture. The (U)SANS results indicated the presence of structures four orders of magnitude larger than the dimensions of a single ND particle, consisting of aggregations of ND particles. This aggregation of the ND particles was studied by employing the contrast variation technique. Two different solvents, namely H2O and dimethyl sulfoxide (and their deuterated counterparts), were used to understand the role of hydrogen in the shape and size of the aggregates. The analysis of experimental data from SANS measurements also reveals the ND particles to have an ellipsoidal structure. Using a defined shape model and the SANS contrast variation technique, it was possible to characterize the non-diamond outer shell of the particles and determine the outer layer thickness. This clarification of the structure of the NDs will allow better preparation of suspensions/samples for various applications. Understanding the structure of NDs at multiple length scales also provides crucial knowledge of particle-particle interaction and its effect on the aggregation structures.

Differentiating Degenerative from Vascular Dementia with the Help of Optical Coherence Tomography Angiography Biomarkers.

Alzheimer’s disease and vascular dementia account for the majority of cases of cognitive decline in elderly people. These two main forms of dementia, under which various subtypes fall, are often overlapping and, in some cases, definitive diagnosis may only be possible post-mortem. This has implications for the quality of care and the design of individualized interventions for these patients. Optical coherence tomography angiography (OCTA) is a non-invasive imaging modality used to visualize the retinal layers and vessels which shows encouraging results in the study of various neurological conditions, including dementia. This review aims to succinctly sum up the present state of knowledge and provide critical insight into emerging patterns of OCTA biomarker values in Alzheimer’s disease and vascular dementia. According to the current literature, vessel density seems to be a common biomarker for both forms; inner retinal layer thickness might represent a biomarker preferentially affected in degenerative dementia including Alzheimer’s, while, in contrast, the outer-layer thickness as a whole justifies attention as a potential vascular dementia biomarker. Radial peripapillary capillary density should also be further studied as a biomarker specifically linked to vascular dementia.

Analysis of Efficiency Of KDT-OAT and Removal Preparations on The Recovery of Pulmonary Tuberculosis

Background: Tuberculosis is one of the 10 most common causes of death and is the single most common cause of infection and causes illness every year in millions of people. The etiology of tuberculosis is the bacteria Mycobacterium tuberculosis and Mycobacterium bovis. These germs have a size of 0.5-4 microns x 0.3-0.6 microns with thin rods, straight or slightly bent, granular or have no sheath, but have a thick outer layer consisting of lipoids (especially mycolic acid). Based on data from the Riset Kesehatan Dasar in 2018 conducted by the Kementerian Kesehatan RI, the prevalence rate of pulmonary TB by doctors in Indonesia in 2018 was the same as in 2013 which was 0.4%. Based on the OAT guidelines used in Indonesia, there are two OAT drug preparations, namely OAT-KDT or (FDC) and the Kombipak package. Comparison of the efficacy of this drug in curing pulmonary TB also varies. Objective: To determine the efficacy of KDT-OAT and removal preparations on the cure rate of pulmonary TB. Methods: This type of research is a retrospective cohort study, which is a time-period approach. This study was conducted in October-November 2020. Results: There was no significant difference in treatment outcomes in pulmonary TB patients who received OAT-KDT or OAT-release preparations.

Comparative study on the blast load response of woven and lattice core metallic sandwich panels

Sandwich structures are potential alternatives to monolithic plates for the purpose of absorbing energy and managing the impulse associated with blast loading. The study of sandwich structures subjected to blast loading is a rapidly expanding area of activity. Sandwich structures are extensively used in blast dissipation applications on account of their excellent physical and mechanical properties. These sacrificial cladding structures absorb energy through progressive plastic deformation of the front-facing plate and the core layer; thus minimizing the transfer of the peak force to the non-sacrificial structure. The core absorbs most of the energy and hence has a significant influence on the blast behavior of sandwich structures. The core layer can have several topologies, which in turn have various configurations. The present study numerically evaluated and compared the effectiveness of using Triangular Woven and Pyramidal Lattice core configurations in sandwich panels for resisting blast loads. The parametric study consisted of the effect of change in outer layer thicknesses of sandwich panels and the application of successive blast loads in the performance of the sandwich panels. The study was conducted for seven outer layer thickness combinations modeled in ANSYS Workbench Explicit Dynamics. All the models were subjected to a blast load with the same scaled distance. The comparison of the simulated results was used to determine the more suitable core configuration for dissipating blast loads. Pyramidal lattice panels were found to be 5% and 48% more efficient than a triangular woven panel of comparable relative core density under normal blast load and successive blast load respectively.

Retinal thickness profiles in patients with Behçet uveitis during remission.

The purpose of this study was to evaluate the intraretinal layer thickness in the macular region and its correlation with the duration of uveitis and visual acuity in patients with Behçet uveitis. In this cross-sectional study, we included 93 eyes of 57 patients with Behçet uveitis and 100 eyes of 50 healthy individuals admitted to a tertiary center from January to September 2017. We performed macular measurements in all subjects via spectral domain-optical coherence tomography (SD-OCT) and divided the retina into layers using automated segmentation software on the SD-OCT device. We then compared layer thicknesses between the patient and control groups and evaluated the correlation between OCT parameters and the duration of uveitis and visual acuity in the patient group. Our records show a mean age of 37.9 ± 10.8 (18-64) years and 37.7 ± 12.2 (21-61) years in the patient and control groups (p=0.821), respectively. Meanwhile, data reveal a mean duration of uveitis of 6.9 ± 4.7 (1-20) years. We found a reduction in the total outer layer thickness in the patient group (p<0.001). However, we did not find a statistically significant difference in the inner retinal layers except in the inner nuclear layer. The duration of uveitis negatively correlated with the outer retinal layer's thickness (correlation coefficient = -0.250). On the other hand, visual acuity positively correlated with the central macular, the total inner layer, and the outer retinal layer thicknesses (correlation coefficients: 0.194, 0.154, and 0.364, respectively). However, the inner nuclear layer negatively correlated with visual acuity. Using retinal segmentation via SD-OCT for follow-ups can help estimate visual loss in patients with Behçet uveitis, which can cause significant changes in intraretinal layers in the macular region.

High temperature oxidation behavior of MoSi2–Al2O3 composite coating on TZM alloy

A novel MoSi2–Al2O3 composite coating was prepared on Mo-based TZM alloy by slurry sintering method. The oxidation behavior of the coating was evaluated at 1600 °C in static air. Microstructure and phase composition of the as-prepared and oxidized coatings were characterized, and the antioxidant mechanism of the coating at high temperature was discussed. A three-layer structure was observed in the as-prepared coating, consisting of a ∼2 μm thick Mo5Si3 diffusion layer, a ∼65 μm thick MoSi2 inner layer and a ∼36 μm thick outer layer of mixture of MoSi2 and Al2O3. After oxidation at 1600 °C for 5 h, all MoSi2 phases were completely converted to intermediate silicide Mo5Si3 by solid-state diffusion, and the formed Mo5Si3 phase would be transformed into Mo3Si phase with further extending the oxidation time. Furthermore, a dense oxide layer of SiO2-mullite was formed on the specimen surface, which can effectively protect the material to further oxidation. The MoSi2–Al2O3 coating could protect the substrate effectively at 1600 °C for 20 h without failure. The enhanced oxidation resistance of MoSi2–Al2O3 coating is due to the formation of multi-layer structure containing a SiO2-mullite composite oxide outer layer with high thermal stability and low oxygen permeability.

Characterization of microstructure and oxidation resistance of Y modified silicide composite coating on Mo–Cr–W–Al–Ti substrate

Y modified silicide composite coating (Si–Y coating) was prepared on Mo–Cr–W–Al–Ti substrate by Si and Y2O3 co-deposition at 1200 °C for 20 h. The oxidation resistance of the coating was studied by analyzing the phase constituents and microstructure. A double layer coating has been observed: a thick outer layer consisting of (Mo, X)Si2, (Cr, X)Si2 and Al2O3, and a thin inner layer of (Mo, X)5Si3, (Cr, X)5Si3, Al2O3. The Si–Y coating possessed better oxidation resistance under high temperature conditions than the unmodified one, the mass gain of 5.97 mg/cm2 after 18 cycles of oxidation at 1300 °C in air for 150 h for the former and the beginning of weight loss after 18 h under the same condition for the latter. The dispersed Y2Ti2O7 contained in the compact SiO2 protective layer acts as a “skeleton” to improve the oxidation resistance of the Si–Y coating.