Layer Thickness Research Articles

Experimental study and neural network model based prediction of layer thickness influence on LPBF IN625 single track geometry

The performance of interacting metal surfaces having sliding motion is enhanced by fabricating microfeatures on-top of the surfaces. Laser powder bed fusion (LPBF) is used to fabricate the microfeatures of IN625 on-top of a flat surface. In LPBF, geometrical characteristics of microfeatures are based on the energy supplied and the volume of material melted (layer thickness) at that instant of time. There is very few research reported in open literature on the effect of layer thickness on microfeatures geometry during LPBF. In this work, a series of single tracks is fabricated with different combinations of laser power and scanning speed for 75 μm, 100 μm, and 125 μm layer thickness and its effect on single track geometrical characteristics and microstructure was evaluated. It has been found that laser power and scanning speed have a significant influence on the track geometry irrespective of layer thickness. The minimum linear energy density of 2.5 J/mm is considered to fabricate the continuous track formation for investigated layer thickness. From statistical analysis, it is observed that the laser power and scanning speed shows higher contribution on track width and remelting depth, respectively. Whereas, layer thickness shows a higher influence on track height and contact angle of single track as compared to laser power and scanning speed. In 125 μm layer thickness, the volume of material melting is increased which encourages the gravity effect to deform the melt pool and produces larger track width compare to 100 μm layer thickness. Further, the cell spacing is gradually increased with layer thickness resulting increase in the solidification period. The shape controllability of the single track is significantly increased with layer thickness, but as keeps on increasing layer thickness due to the larger volume of molten metal, the melt pool losses ability to maintain convex shapes. An Artificial Neural Network (ANN) model is developed to understand the relationship between the LPBF process parameters and single track geometrical characteristics to predict the responses for a wide range of process parameters. The multiple response neural network model shows excellent agreement with experimental results with R2 value greater than 0.95.

Research on the interfacial microstructure and mechanical properties of glass/Mg joint prepared by anodic bonding and vacuum diffusion bonding

The joining of glass and Mg by a combination of anodic bonding and vacuum diffusion bonding with Al as the interlayer was achieved in one step. The microstructures of glass/Mg dissimilar joints were analyzed using optical microscopy, SEM, and EDS. The results show that the bonding interface was joined well without any voids and cracks. Na+ and Ca2+ depletion regions would be produced in the glass near the Al foil, where the width of the Na+ depletion region was larger than that of the Ca2+ depletion region. In addition, the content of Al element in the depletion regions increased, and the diffusion of Al into the depletion regions was responsible for the successful glass/Al bonding process. Al3Mg2 and Al12Mg17 intermetallic compound (IMC) layers were formed between the Al and Mg. The anodic bonding process and the vacuum diffusion bonding process were independent of each other: and the thickness of the IMC layer increased with the increase of the diffusion bonding time, while the width of the Na+, Ca2+ depletion region remained constant; Meanwhile, the variation of the anodic bonding parameters only affected the width of the depletion layer and had no effect on the thickness of the Al3Mg2 and the Al12Mg17 IMC layer. The fracture position of the sample changed from the Al/Mg bonding interface to the glass/Al bonding interface as the thickness of the IMC layer increased. The maximum tensile strength of 14.6 MPa was obtained by vacuum diffusion bonding at 450 °C for 20 min and anodic bonding under 400 °C and 800 V.

Improvement of ferroelectric and dielectric properties in BaTiO3/LaNiO3 superlattices by regulating the ferroelectric layer thickness

Ferroelectric superlattices exhibit rich functional characteristics. Yet, the ferroelectric properties are always unsatisfactory due to the presence of depolarization field resulting from the polarization discontinuities between the component materials, which has become a bottleneck problem hindering the improvement of ferroelectric properties and further industrial applications. Here, the BTO/LNO superlattices composed of ferroelectric (BaTiO3, BTO) and metallic (LaNiO3, LNO) materials were prepared by pulsed laser deposition (PLD). The periodic thickness of the LNO layers was fixed to 2 unit cells, while the periodic thickness of the BTO layers was changed. We demonstrate experimentally that by regulating the BTO periodic thickness, BTO/LNO superlattices exhibit excellent and adjustable ferroelectric and dielectric properties. The enhancement of electrical properties is closely related to the increase of tetragonality (c/a) combined with the effect of the ultra-thin LNO layers and the accumulation of oxygen vacancies at superlattice interfaces on reducing the depolarization field. We hope this work will provide an effective strategy for optimizing the ferroelectric properties of ferroelectric superlattices based on the component material and periodic structure regulation.

Influence of surface texture and coating thickness on adhesion of nickel plated coatings to aluminium substrate

Adhesion of coating to substrate has been a challenge due to the hybrid effects induced by surface roughness. In this study, the adhesion of electroplated nickel and electroless NiP layers of different thicknesses ranging from 5 to 20 μm, as metal coatings, applied to aluminium substrates of different surface conditions, has been evaluated. Different processes including grinding, polishing, sandblasting and laser surface texturing were used to produce a series of roughness/surface textures on the substrate coupons. Adhesion of the coatings was assessed by bending test qualitatively as well as semi-quantitatively. It was found that surface texture isotropy/anisotropy (value of <0.1 and >0.8) and skewness significantly affect the delamination of plated coatings. With the increase in layer thickness, it was realized that the coating cracks and delamination increased and adhesion strength decreased by 14 % on average.

Viscoelastic characterization of coating layers by ultrasonic interference and critical attenuation

This study proposes a characterization technique for a viscoelastic coating layer on a metal substrate immersed in water based on ultrasonic interference and critical attenuation phenomena. Theoretical analysis shows that the reflection spectrum for the normal incidence wave has local minima at the resonance frequencies of the coating layer, which provide its elastic property if the layer thickness is given a priori. Furthermore, it is revealed that the lower envelope of the reflection spectrum takes a minimum, whose frequency can be related to the critical attenuation condition. This feature implies a possibility that the viscous property of the coating material can be estimated by similarly measuring a characteristic frequency to the estimation of the elastic property. Two bonded specimens consisting of polycarbonate (PC) sheets and metal substrates were prepared to validate the proposed method. The reflection spectra measured for the normal wave incidence showed multiple local minima and critical attenuation, which are predicted to appear by theoretical predictions. The wave velocities and loss factors of PC estimated from the two specimens are in fair agreement with the properties shown in the previous paper. This result demonstrates that the ultrasonic interference and critical attenuation behavior can be applied to the characterization of the viscoelastic coating layers.

Investigation of the shape-changing property of X-ray computed tomography in the evaluation of pores

Porosity in additive manufacturing is one of the main quality characteristics for components. In processes such as laser-based powder bed fusion of metals (LPBF-M), correlations can be observed between the process parameters used, such as laser power, hatch distance or layer thickness, and the pore shape produced. Therefor the surface depending criterion sphericity is a crucial parameter for the classification of pores. In addition to methods like micrographs or Archimedes' density determination, industrial X-ray computed tomography (CT) is a key measurement method for the spatial but also shape-dependent assessment of pores in components. However, due to the lack of standards, no measurement uncertainty for shape, position, and volume can be given for CT measurements. With the help of CT simulations and models for detector and X-ray source to real CT system, investigations can be made on the dependencies and influence on the detectability of pores. This study shows that the CT measurements as well as the analysis have an influence on the detectable volume and surface of pores. By modelling pore models with cosine periodic spatial frequencies (peaks), the spatial influence of CT on detectability can be investigated and assessed as a form of slope distribution. The simulation-based measurement uncertainty information can be used to improve the separation of pore shape classifications and thus contribute to the development of additive manufacturing.

CLINICAL CHARACTERIZATION OF AQUEOUS AND VITREOUS RETINOL-BINDING PROTEIN 3 CONCENTRATIONS IN RELATION TO DIABETIC RETINOPATHY SEVERITY, RETINAL STRUCTURES, AND SYSTEMIC COMPLICATIONS.

To evaluate Retinol-Binding Protein 3 (RBP3) from photoreceptors in aqueous and its association with vitreous concentrations, diabetic retinopathy (DR) severity, retinal layer thickness, and clinical characteristics in people with diabetes. RBP3 concentration was measured by custom-developed enzyme-linked immunosorbent assay in aqueous and correlated with vitreous concentrations in patients from the 50-Year Medalist study and Beetham Eye Institute at Joslin Diabetes Center. Aqueous RBP3 concentration (N = 131) was elevated in eyes with no to mild DR (mean ± SD 0.7 nM ± 0.2) and decreased in eyes with moderate to severe DR (0.65 nM ± 0.3) and proliferative DR (0.5 nM ± 0.2, P < 0.001) compared to eyes without diabetes. Aqueous and vitreous RBP3 concentrations correlated with each other (r = 0.34, P = 0.001) and between fellow eyes (P < 0.0001). History of retinal surgery did not affect aqueous RBP3 concentrations, but cataract surgery affected both vitreous and aqueous levels. Elevated aqueous RBP3 concentration associated with increased thickness of the outer nuclear layer (P = 0.004) and correlated with hemoglobin A1c, whereas vitreous RBP3 concentrations correlated with diabetic systemic complications. These findings suggest that aqueous RBP3 concentration may be an important endogenous clinical retinal protective factor, a biomarker for DR severity, and a promising VEGF-independent clinical intervention target in DR.

The construction of iron-based catalysts encapsulated by graphite for CO2 hydrogenation to light olefins

Developing efficient catalytic materials and unveiling the active factors are significant for selective hydrogenation of CO2 to light olefins (C2–4=). Herein, Fe3O4-FeCx nanoparticles coated by graphite without other doped elements were synthesized successfully. The optimal catalyst exhibited CO2 conversion of 48.0 %, C2–4= space–time yield of 29.0 mmol·g−1·h−1, and a stability of 100 h (3.0 MPa, 320 °C, and GHSV = 12000 mL·g−1·h−1). The core–shell structure derived from the strong interaction between the phenolic hydroxyl group of resin and iron ions, as well as the encapsulation of the copolymer P123. The characterization results revealed that the size of core–shell particles and thickness of graphite layers could be regulated by P123, which affected the conversion of CO2 and products distribution significantly. Moreover, the combined results of quasi in-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTs) and Raman spectra suggested small particle size and thin graphite shell strengthen the adsorption and conversion of CO2, playing an important role in the formation of light olefins. This work proposes a simple and feasible synthesis strategy to construct Fe3O4-FeCx particles encapsulated by graphite shell, which provides insights into catalysts design and the reaction mechanism of CO2 conversion to light olefins.

Modeling and performance investigation of novel inorganic Cs4CuSb2Cl12 nanocrystal perovskite solar cell using SCAPS-1D

For the next generation of photovoltaic devices, perovskite solar cells (PSCs) appear as a good choice because they are simple and convert energy to electricity very efficiently. Recent years have seen a great deal of interest in organic-inorganic lead halide perovskites due to their exceptional optoelectronic properties. Nonetheless, additional commercialization of the Pb element is still restricted by its inevitable toxicity. To address the instability and toxicity of the lead hybrid perovskite, it is imperative to produce entirely inorganic lead-free perovskite nanocrystals. Cs4CuSb2Cl12 offers promising qualities and strong stability against light, heat, and humidity to overcome these drawbacks. It possesses an efficient photo-generated carrier and good carrier mobility. In this study, a lead-free perovskite solar cell with the novel configuration of FTO/WS2/Cs4CuSb2Cl12/CuSbS2/Ni has been optimized using SCAPS-1D simulation software and investigates the potential of Cs4CuSb2Cl12 nanocrystal solar cell. The impact of different characteristics of charge transport materials on Cs4CuSb2Cl12 nanocrystal solar cells has been reported. Additionally, the study computationally optimizes the thickness of perovskite layer, doping concentration, defect density, and other input parameters to propose an effective PSC with power conversion efficiency of 23.10 %, Voc of 1.1675V, and FF of 83.33 %.

Engineering the SiOx interfacial layer of Si-based metal-insulator-semiconductor junction for photoelectrochemical hydrogen production

Photoelectrochemical (PEC) water splitting provides a potential method to produce renewable hydrogen energy, but there is still plenty of room for improving the efficiency and stability of photoelectrodes. In this paper, we present a metal–insulator-semiconductor (MIS) structure based on p-Si that enables stable and efficient water splitting by engineering the interfacial insulating layer. The silicon oxide (SiOx) film with appropriate thickness and low defects is regrown by a chemical oxidation process, which provides a high-quality insulating layer to passivate the p-Si. The carrier flux, barrier height and interfacial resistance of p-Si based MIS junction can be systematically tuned by controlling the thickness and quality of SiOx layer. Under AM 1.5G illumination, the optimized p-Si/SiOx/Ti/Pt photoelectrode shows an onset potential of 0.5 V vs. RHE, a maximum photocurrent of 28 mA/cm2 and a high applied bias photon-to-current efficiency (ABPE) of 6 %. These results have significant implications for constructing MIS photoelectrodes towards effective water splitting.

Indium-free nonmetal and Nb co-doped anatase TiO2 transparent conductive oxide materials for photovoltaic applications: From first-principles calculations to macroscopic simulation

Various researchers have attempted to design indium-free transparent conductive materials. This study first employed density functional theory combined with the Hubbard U parameter to predict the photoelectric properties of nonmetal (B, C, N, F, P, and S) and Nb co-doped anatase TiO2. The results indicate that Ti0.875Nb0.125O1.96875N0.03125, Ti0.9375Nb0.0625O1.96875F0.03125, Ti0.875Nb0.125O1.96875P0.03125 and Ti0.9375Nb0.0625O1.96875S0.03125 possess characteristics of n-type semiconductors with high transmittance, exceptional thermal stability and wide bandgap. Notably, Ti0.9375Nb0.0625O1.96875S0.03125 exhibits optimal electronic conductivity due to its lower effective mass and higher electron concentration. Then, we used the SCAPS-1D solar cell simulation software to simulate the macroscopic characteristics of the MASnI3-based perovskite solar cell with Ti0.9375Nb0.0625O1.96875S0.03125 transparent conductive oxide layer based on the microscopic properties computed at the density functional theory level. A maximum efficiency of 27.17 % is obtained by regulating the thickness, electron affinity, and defect density of Ti0.9375Nb0.0625O1.96875S0.03125 layer and the thickness of MASnI3 absorber layer. The findings highlight the tremendous potential of Ti0.9375Nb0.0625O1.96875S0.03125 as an indium-free transparent conductive oxide candidate material for photovoltaic applications.

Enhancing CdSe/ZnS Quantum-Dot Light-Emitting Diode Performance: The Impact of Thermal Treatment Atmospheres on Fabrication Processes

We explored the thermal treatment impact on the performance of quantum-dot light-emitting diodes (QLEDs). The QLEDs comprised multiple layers: a 2.2-μm thick epoxy buffer layer; a bottom cathode composed of 12-nm MoOx/10-nm Ag/12-nm MoOx; a 20-nm ZnO electron transporting layer (ETL); a 10-nm CdSe/ZnS quantum dot light emission layer (EML); a 40-nm 4,4′,4″-Tris(carbazol-9-yl) triphenylamine hole transporting layer; a 10-nm WOx hole injection layer; and a 100-nm Ag top anode. We applied thermal treatments to the cathode, ETL, and EML separately to assess their effects on the QLEDs. Additionally, we evaluated the impact of the thermal treatment atmosphere. Vacuum thermal treatment on the cathode and EML resulted in minor improvements in QLED performance, whereas treatment of the ETL led to a decline in performance. In contrast, air thermal treatment on the cathode and EML decreased QLED performance but significantly improved it by 15% in current efficiency when applied to the ETL. The performance differences attributable to the thermal treatment atmosphere are likely due to ligand removal and oxidation processes, facilitated by thermal energy and oxygen. Our study highlights that air thermal treatment on the ETL substantially improves QLED performance, offering crucial insights into the significance of thermal treatment in QLED development.

Bacillus subtilis and xylo-oligosaccharide ameliorates NaHCO3-induced intestinal barrier dysfunction and autophagy by regulating intestinal microflora and PI3K/Akt pathway of crucian carp (Carassius auratus)

This study was to demonstrate that the alleviate effect of synbiotics (Bacillus subtilis and xylo-oligosaccharide) on NaHCO3-induced intestinal barrier dysfunction and autophagy of crucian carp (Carassius auratus). In a 2×2 factorial design, crucian carp were divided into 4 groups, fed with diets contained two levels of synbiotics (0 and 1× 108 CFU/g) and treated with two levels of NaHCO3 (0 and 50 mmol/L) for 56 days. The results showed that NaHCO3 and synbiotics significantly affected intestinal fold height, permeability, the mRNA expression of tight junction, antioxidant capacity, immunity function (except LZM), inflammation response, the mRNA and protein expression of autophagy (except Beclin1 protein) and PI3K/Akt pathway (P<0.05). Intestinal muscular layer thickness, the levels of LZM and the protein expression of Beclin1 only affected by NaHCO3 (P<0.05). In addition, the interaction between NaHCO3 and synbiotics was observed for intestinal fold height, the mRNA expression of Claudin 4, Nrf2, Keap1, HO-1, SOD, GPX4a, GPX4b, TNF-α, IL-6, PI3K, ATG5 and ATG7, the levels of ROS and ACP, the protein expression of p-PI3K/PI3K, p-Akt/Akt, ATG5, ATG7, Beclin1 and LC3Ⅱ/LC3Ⅰ (P<0.05). Additionally, this study highlights that the synbiotics facilitated the colonisation Bacillus and Cetobacterium, while concurrently inhibited the growth of Aeromonas in intestines. These findings suggested that dietary synbiotics (Bacillus subtilis and xylo-oligosaccharide) can effectively alleviated NaHCO3-induced intestinal dysfunction oxidative stress and autophagy by regulating intestinal microflora and PI3K/Akt pathway.

Combining dip-coating and rotate-drying to preparation of PDMS on SiC tubular support with macropore for high pervaporation performance

High-performance polydimethylsiloxane (PDMS)/ceramic tubular pervaporation membranes have potential in industrial separation applications, but realizing the preparation of PDMS layer on the ceramic supports with micrometer-scale pore size (0.8 μm or 4.3 μm) for improving performance remains a challenge. We report a strategy (combined dip-coating and rotate-drying, DCRD) to preparation of PDMS on silicon carbide (SiC) tubular support with macropore. Response surface methodology was employed to optimize the dip-coating process, and the influence of friction velocity on tubular composite membranes was investigated. The results indicate that pulling speed, casting solution viscosity, and their interaction have significant effects on the pervaporation performance of PDMS/SiC tubular composite membranes. Moreover, increasing friction velocity results in uneven PDMS layer thickness, which in turn impacts the pervaporation performance of the composite membrane. Furthermore, the rigid structure of SiC restricts the movement of PDMS polymer chains, enabling the composite membrane to maintain stable pervaporation performance at higher isobutanol feed concentrations (3 wt%) or elevated feed temperatures (60 °C). After continuous operation for 200 hours, the developed PDMS/SiC tubular composite membrane consistently maintained the total flux of 650 g·m-2·h-1 and the separation factor of 39 for isobutanol/water. Eventually, this novel fabrication method offers new insights into the preparation of various other organic-inorganic tubular composite membranes.

Influential Signs of Dry Eye-Related Ocular Symptoms in Participants With Unstable Tear Film.

The aim of this study was to investigate the factors influencing dry eye disease (DED)-related ocular symptoms in participants with short fluorescein tear break-up time (FTBUT). This cross-sectional study included 82 participants with short FTBUT (<10 seconds). Examinations included Ocular Surface Disease Index (OSDI), FTBUT, average noninvasive tear break-up time (NIBUTave), lid wiper epitheliopathy, lipid layer thickness, blink rate, partial blink, tear meniscus height, and meibomian gland (MG) evaluation which included ratio of residual MG area (RMGA) and MG grade in tarsal plates. One-way analysis of variance was used to detect differences between symptomatic tear film instability group (FTBUT <5 s, OSDI ≥13), asymptomatic tear film instability group (FTBUT <5 s, OSDI <13), and control group (FTBUT ≥5 s, OSDI <13). A bivariate correlation, partial correlation, and multiple linear regression analyses were used to identify major factors. Only the right eye was included. Among the participants with FTBUT <5 seconds, symptomatic group showed less upper RMGA ( P < 0.001) and NIBUTave ( P = 0.010). OSDI was negatively associated with upper RMGA ( r = -0.450, P < 0.001) and NIBUTave ( r = -0.414, P = 0.001), and positively associated with upper MG grade ( r = 0.277, P = 0.027). Linear regression analysis showed that the upper RMGA significantly affected OSDI (B = -41.895, P = 0.001), while not significantly correlated with age, upper MG grade, and NIBUTave. The upper RMGA might be the main factor affecting DED-related discomfort in participants with unstable tear film, indicating an early ocular change in DED.

Linkage of Diabetic Retinopathy with Blood Antioxidants and Gut Microbiota in Type Two Diabetes Mellitus Saudi Patients

Background: The retina is a light-sensitive nerve layer located at the back of the eye that creates images of objects. These cells kept alive by getting oxygen and nutrients from tiny blood vessels in the eye. Retinopathy is a disease of the retina that is more prevalent in type 2 diabetes mellitus patients. Diabetic retinopathy is a leading cause of blindness because hyperglycemia weakens retinal capillaries, resulting in leakage of blood into the surrounding space. This bleeding can result in formation of scar tissue, which can cause traction retinal detachment and maculopathy. The development of a panel of blood biomarkers to monitor diabetic retinopathies is essential for both diagnosis and prognosis. Proteomics as a powerful tool for the analysis of complex mixtures of proteins and the identification of biomarkers can be of great importance. Purpose: To detect early nerve fiber layer changes around macula and optic disc in diabetic patients and to correlate diabetic retinopathy with blood antioxidants and gut microbiota in T2DM in Saudi patients. Materials and Methods: In this cross-sectional case-control study, a total of 77 eyes of 39 subjects aged 40-60 years who did not have any history of eye injuries or eye diseases affecting fundus viewing, were recruited from King Saud University Campus and the department of ophthalmology in King Abdul Aziz university hospital in Riyadh. All subjects underwent full ophthalmic examination including Peripapillary retinal nerve fiber layer thickness and macular profile, Proteomic approach of collected overnight fasting plasma and Microbial stool examination. Results: The nerve fiber layer thickness around the optic disc was measured for all groups and there was no statistically significant difference in all quadrants between groups. The total retinal thickness at the macular area was different among all groups and tends to increase in group 3 due to diabetic retinopathy. The macular thickness in the 4 quadrants revealed no statistical difference except in the inferior quadrant. Glutathione S transferase and lipid peroxides showed no significant difference between the three studied groups; vitamin C and Glutathione were surprisingly higher in controlled diabetic patients relative to controls. Moreover, over growth of bacteroids participated to the evolution of retinopathy in diabetic patients. Conclusion: As hyperglycemia and oxidative stress are implicated in the pathogenesis of diabetic retinopathy, the present study certified that the progressive damage can be delayed in controlled type 2 diabetic patients using different treatment modalities that subside oxidative stress.

Effect of printing parameters on impact energy absorption of additively manufactured hierarchical structures

Purpose This study aims to examine how the thickness of layers and printing speed impact the energy absorption capacity of honeycomb structures through drop-weight experiments. In addition, the effect of printing orientation on the resulting microstructure and mechanical performance was targeted to be examined. Design/methodology/approach In this paper, after manufacturing test specimens using fused deposition modeling technique with three distinct layer thicknesses (0.16 mm, 0.20 mm and 0.28 mm) and printing speeds (40 mm/min, 50 mm/min and 70 mm/min), drop weight tests were carried out. Then to see the effect of printing orientation on mechanical performance, three-point-bending tests were performed and damage mechanisms were comparatively examined through scanning electron microscopy. Findings An increase in layer thickness from 0.16 mm to 0.28 mm resulted in a notable 37% decrease in the impact resistance of the printed part. In addition, increasing the printing speed from 50 to 70 mm/min reduced the energy absorption capacity of the printed part by approximately 36.5%. Moreover, in terms of printing direction, transversely printed specimens showed 10% lower flexural strength than longitudinally printed specimens. Finally, scanning electron microscopy (SEM) observation showed that internal defects were more prominent in transversely printed specimens, resulting in premature failure. Furthermore, delamination was also detected in transversely printed specimens as another damage mechanism accelerating material failure. Originality/value It is seen that the effect of printing parameters on the fundamental mechanical properties including tensile strength, strain at break, ductility and elastic modulus were studied by various researchers. However, to the best of authors’ knowledge, the effect of printing speed and layer thickness on the energy absorption of polylactic acid based hexagonal honeycomb was not encountered. In addition, in-depth SEM analysis to discover the influence of printing direction significantly contributes to the literature.

Fabricating Ultrathin Imprinting Layer for Fast Capture of Valsartan via a Metal Affinity-Oriented Surface Imprinting Method.

Rapid separation and enrichment of targets in biological matrixes are of significant interest in multiple life sciences disciplines. Molecularly imprinted polymers (MIPs) have vital applications in extraction and sample cleanup owing to their excellent specificity and selectivity. However, the low mass transfer rate, caused by the heterogeneity of imprinted cavities in polymer networks and strong driving forces, significantly limits its application in high-throughput analysis. Herein, one novel metal affinity-oriented surface imprinting method was proposed to fabricate an MIP with an ultrathin imprinting layer. MIPs were prepared by immobilized template molecules on magnetic nanoparticles (NPs) with metal ions as bridges via coordination, and then polymerization was done. Under the optimized conditions, the thickness of the imprinting layer was merely 1 nm, and the adsorption toward VAL well matched the Langmuir model. Moreover, it took just 5 min to achieve adsorption equilibrium significantly faster than other reported MIPs toward VAL. Adsorption capacity still can reach 25.3 mg/g ascribed to the high imprinting efficiency of the method (the imprinting factor was as high as 5). All evidence proved that recognition sites were all external cavities and were evenly distributed on the surface of the NPs. The obtained MIP NPs exhibited excellent selectivity and specificity toward VAL, with good dispersibility and stability. Coupled with high-performance liquid chromatography, it was successfully used as a dispersed solid phase extraction material to determine VAL in serum. Average recoveries are over 90.0% with relative standard deviations less than 2.14% at three spiked levels (n = 3). All evidence testified that the MIPs fabricated with the proposed method showed a fast trans mass rate and a large rebinding capacity. The method can potentially use high-throughput separation and enrichment of target molecules in batch samples to meet practical applications.

Foveal thickness and its association with visual acuity in adults born preterm with very low birth weight: A two-country birth cohort study.

To explore foveal and parafoveal thickness in adults born preterm with very low birth weight (VLBW) and its association with best-corrected visual acuity (BCVA) and gestational age (GA) compared to adults born at term. In a joint study of the Helsinki Study of Very Low Birth Weight Adults (Finland) and the NTNU Low Birth Weight Life study (Norway), 106 VLBW and 143 term-born controls were examined with spectral-domain optical coherence tomography and BCVA at age 31-43 years. Thickness of retinal layers was segmented in the foveal and parafoveal areas of the macula. The total retinal thickness in the foveal area was thicker in VLBW adults compared with controls; mean (SD): 292.5 μm (28.2) and 272.4 μm (20.2); p < 0.001, and thinner in the parafoveal areas of the macula. These findings could be explained by a thicker inner retinal layer in the foveal area found in VLBW adults compared with controls (mean difference 20.4 μm; CI: 15.0 to 25.9), where a thicker fovea was associated with lower GA, but not BCVA. Adults born preterm with VLBW had a thicker retina in the foveal area than controls and this was associated with GA, but not with BCVA. These changes seem to be related to a thicker inner retinal layer in VLBW adults. The findings imply that signs of macular underdevelopment are still present in adulthood, but not necessarily related to reduced visual function.

The Influence of Selected Process Parameters on the Efficiency of the Process of Gas Nitriding of AISI 1085 Steel

The main aim of the manuscript was to investigate the impact of modifying the parameters of the gas nitriding process of samples made from AISI 1085 steel on the course and results of the process carried out in a chemical reactor allowing for thermogravimetric measurements. The tested steel was subjected in a chemical reactor to the process of gas nitriding in the temperature range of 490–580 °C, using different sample heating rates (in the range of 1–25 °C/min) and various mixtures of nitriding gases (pure NH3, or NH3 with the addition of H2 or N2). To assess the impact of the tested process parameters on its efficiency, the thickness of the nitrided layers produced, the change in sample mass, the structure of the phases produced, the phase composition and the microhardness were examined. For the research methodology used, it was found that reducing the amount of NH3 and/or using H2 or N2 admixtures adversely affects the thickness of the nitride layers produced. At the same time, the use of a lower maximum process temperature with the same gas mixture resulted in a significant difference in the thickness of the layers. It was also found that the use of pure NH3 or a gas mixture (NH3 + H2) with higher NH3 contents resulted in higher surface microhardnesses of the samples and that for these samples, the hardness increased to a greater depth.