Migration Length Research Articles

Cerium rare-earth ions reinforced built-in electric field to enable efficient carrier extraction for highly efficient and stable perovskite solar cells

Perovskite solar cells prepared by inorganic-organic three-dimensional hybrid have good power conversion efficiency, but their operational stability remains a major challenge for commercialization. The defect of perovskite is an important factor restricting its charge dynamics and stability. Here, the rare earth metal chloride CeCl3 is introduced into perovskite solution to passivate the defects, where the Pb2+ part of the B position is replaced by Ce3+. The prepared films have the characteristics of increasing grain size, enhancing carrier mobility and excellent crystallinity. Meanwhile, via passivating interface defects and improving carrier transport capacity, the generation of non-radiative recombination is reduced, the carrier migration length is extended, and the device performance is improved. The results show that the PCE of the standard device is only 65 % after 2880 h of N2 atmosphere at room temperature, while the efficiency of the device doped with CeCl3 can remain at 93 %. When the unencapsulated sample was placed in an air environment (40–60 % humidity), the control sample was reduced to 72 % at 1060 h, while the CeCl3 was maintained at 87 %. Additionally, the reduction of residual stress in the perovskite layer also provides good bending stability for the flexible target device. These results show that the incorporation of rare earth metal ions is an effective way to stabilize and improve the efficiency of the device.

MDB-85. THE MIGRATORY ROLE OF BAIAP2 IN MEDULLOBLASTOMA

Abstract BACKGROUND Medulloblastoma is the most common malignant brain tumor in adolescents. There is still a dire need for a more effective treatment despite advances in technology. One challenge in treating medulloblastoma is its migratory and invasive properties. The underlying mechanisms that lead to these characteristics are still not understood. METHODS We sought to identify targets related to invasion and migration in medulloblastoma, first by mining single-cell RNA sequencing and microarray data. RESULTS We determined that BAIAP2 is differentially expressed in medulloblastoma compared to non-tumor brain cells and other brain cancers. In addition, there is a significant increase in BAIAP2 in metastatic medulloblastoma compared to non-metastatic. We found that CDC42 and RAC1, small GTPases, are protein-protein interactors with BAIAP2. In three medulloblastoma cell lines, we have demonstrated that these genes modulate each other’s expression. Furthermore, we show that the knockdown of BAIAP2, CDC42, and RAC1 decreases medulloblastoma cell migration and filopodia length. Using surface plasmon resonance, we identified compounds that target BAIAP2 protein. After characterizing these compounds, we have identified potential compound candidates that target these genes and impede their roles in migration and invasion in medulloblastoma. CONCLUSIONS These findings demonstrate a migratory role for BAIAP2 in medulloblastoma through the modulation of CDC42 and RAC1. We also demonstrate that BAIAP2 is a therapeutic target and have identified novel compounds that target it.

Controlling the morphology of polycrystalline diamond films via seed density: Influence on grain size and film texture

Controlling the morphology of polycrystalline diamond (PCD) films is crucial for various applications, including thermal management and quantum sensors. PCD films are typically produced by plasma-enhanced chemical vapor deposition on substrates seeded with nanodiamonds. Different film morphologies can be achieved by controlling growth rates of crystal-forming facets, which is commonly managed through deposition temperature and hydrocarbon concentration in the plasma. However, the impact of seed density on film morphology remains largely unexplored. In this study, we observed that reducing seed density on silicon substrates has a similar effect on PCD film morphology as increasing hydrocarbon concentration in the plasma. Specifically, as seed density decreases, deposition rate increases, and film texture transitions from (1 1 1) to (1 0 0), followed by the formation of large grains with (1 0 0) facets surrounded by clusters of small grains. These changes were observed using electron microscopy, Raman spectroscopy, and X-ray diffraction. To explain our results, we hypothesize that the silicon–plasma interface surrounding the growing diamond seeds acts as a diamond precursor source. Our proposed explanation requires relatively long precursor migration lengths compared to those assumed in standard diamond deposition theory. Finally, we also propose two new mechanisms for diamond precursor adsorption based on well-established physical phenomena and recent publications. Our findings may open new avenues in diamond research, applicable not only to polycrystalline but also to single-crystal diamond deposition.

Improved charge kinetics of BiVO4/MoS2 photoanode by an TiO2 electron transport layer for photocatalytic fuel cell photodegradation and electricity generation

The poor contact between the photocatalyst and the FTO substrate are the main factors lead to the low performance of photocatalytic fuel cell (PFC). Herein, a FTO pre-treated with a TiO2 electron transport layer was used as a substrate for the synthesis of the MoS2/BiVO4/pre-FTO photoanode. The proposed MBV-4/pre-FTO photoanode with its enhances the visible light absorption and effectively delays the recombination of the photoexcited charge. The MBV-4/pre-FTO composite photoanode (6.02 mA/cm2) exhibited a photocurrent density that was 2.2 times higher than that of the BiVO4 photoanode (2.78 mA/cm2). This is attributed to the short charge migration length of the thin MoS2 layer, the fast photoexcited electron transport effect of the TiO2 seed layer, and the heterojunction structure of the proposed photoanode. The DFT calculation result indicated that the TiO2 electron transport layer showed an outstanding photoelectron attractive and transporting effect. The MoS2/Ni foam was employed as the photocathode to establish a mismatched Fermi level for driving PFC. The short-circuit current, open-circuit voltage, and maximum power density of the PFC were 0.578 mA/cm2, 0.632 V, and 0.125 mW/cm2, respectively. The main photodegradation active species are the superoxide anion (∙O2–) and the photoexcited hole (h+), and the degradation efficiency is 61.97 %.

Atomically Contacted Cs3Bi2Br9 QDs@UiO-66 Composite for Photocatalytic CO2 Reduction.

Metal halide perovskite quantum dots (QDs) are widely studied in the field of photocatalytic CO2 due to their strong light absorption and long carrier migration length. However, it can not exhibit high catalytic performance because of the radiative recombination and the lack of effective catalytic sites. Metal organic frameworks (MOFs) encapsulated QDs can not only solve the aforementioned problems, but also maintain their own unique characteristics with ultra-high specific surfaces area and abundant metal sites. In this work, lead-free bismuth-based halide perovskite QDs are encapsulated into Zr-based MOF (UiO-66), which combines the advantages with high power conversion efficiency of QDs and the high surface area and porosity of UiO-66. In addition, benefiting from the close contact between the Cs3Bi2Br9 QDs and the UiO-66 enables the photogenerated electrons in the QDs to be rapidly transferred to the MOF. As a result, the Cs3Bi2Br9@UiO-66 composite exhibits a higher yield for photocatalytic CO2 reduction than that of the prepared large-sized composite of Cs3Bi2Br9 and UiO-66.

Anti-Angiogenic Effect of Clerodendreme inerme Leaves Extract

Clerodendrum inerme, a medicinal plant, exhibits diverse pharmacological properties. Various species within the Clerodendrum genus have been traditionally utilized in indigenous medical systems and folk remedies. This study intended to scrutinize the anti-angiogenic possibility of CI through in-ovo, in-vitro, and in-vivo approaches. The screening methods employed include the chick chorioallantoic membrane test (in-ovo), sponge bud technique (in-vivo), as well as in-vitro assays for cell migration, cell proliferation, along with morphogenesis. Statistical analyses involved Dunnett’s test for mean comparisons, utilizing one-way ANOVA. In the chick chorioallantoic membrane assay, both angiogenic score and branching points were evaluated. Notably, CI exhibited noteworthy antiangiogenic effects. In the sponge implantation technique, CI at specified dosages resulted in a substantial reduction in sponge weights, the formation of new vessels, and hemoglobin levels. The antiangiogenic effects were particularly pronounced with increasing doses. Furthermore, on endothelial cells, C. inerme demonstrated a dose-dependent decrease in migration, proliferation, and tube length, indicating potent antiangiogenic properties. In summary, this research underscores the considerable antiangiogenic potential of CI by various assays.

Uranium migration lengths in Opalinus Clay depend on geochemical gradients, radionuclide source term concentration and pore water composition

Abstract. Safety assessments of highly radioactive waste disposal sites are done based on simulation of radionuclide migration lengths through the containment providing rock zone. For a close to real case situation, the present model concept established for uranium is derived from the hydrogeological evolution and geochemical and mineralogical data measured at the deep geothermal borehole Schlattingen including the effect of geo-engineered barriers on the source term. In the Schlattingen area, the Opalinus Clay is tectonically undeformed compared to the Mont Terri anticline and represents the geochemical and temperature conditions at the favoured disposal depth. The geochemical conditions are more or less constant with slightly decreasing concentrations of pore water components towards the footwall aquifer. Uranium migrates less compared to the Opalinus Clay system at Mont Terri, where gradients of pore water geochemistry towards the embedding aquifers are more pronounced. This means, stable geochemical conditions with no or low concentration gradients are to be favoured for a safe disposal since migration lengths strongly depend on spatial and temporal variation of the hydrogeological and geochemical conditions within the host formation. The engineered barriers reduce the source term concentration what, in turn, is associated with a decrease in uranium migration. Stable geochemical conditions further enable the application of the Kd approach to estimate the impact of the barriers. The hydrogeological system must always be considered when quantifying radionuclide migration.

Hydrogeochemical impact of Opalinus Clay system shown in migration lengths of uranium

Abstract. Models and simulations allow a prognosis of how processes in the geosphere might occur in the future by considering physical and chemical processes. They are the only way to test future scenarios and hypotheses and to evaluate how a repository site will develop over a period of a million years, e.g. by quantifying potential radionuclide migration in the hydrogeological system of the containment providing rock unit. An example is used to demonstrate the extent to which simulated migration lengths can vary for a million years, depending on the model concept and on the underlying data and parameters. In the case of uranium in the potential host rock Opalinus Clay (Switzerland), the range extends from 5 m, by applying experimentally determined transport parameters, over 50 m, using process-based approaches and taking hydrogeology into account, and up to 80 m, depending on the thermodynamic data set used. The degree of reliability of the models is derived from comparison with laboratory tests, data from boreholes and underground laboratories or natural analogues. This is the only way to assess the simulation results. In addition, indications can be provided regarding where new data need to be collected. So our task is to find an answer to the following question: how accurate do the models for the repository site search have to be in order to produce resilient and robust forecasts? To reduce the uncertainty related to the migration length of uranium in the Opalinus Clay, the calcite carbonate ion and the hydrogeological system at a potential disposal site need to be known, whereas the quantity of clay minerals plays a subordinate role, as long as it is enough, which is the case in argillaceous formations.

Analysis of polyisoprene oligomers via in situ silver nanoparticle formation on thin-layer chromatography plate using matrix-assisted laser-induced desorption/ionization mass spectrometry.

The direct mass spectrometry (MS) detection of polyisoprene (PI) oligomers on a thin-layer chromatography (TLC) plate using matrix-assisted laser-induced desorption/ionization (MALDI) with silver trifluoroacetate as the cationization reagent was investigated. The spots of PI oligomers and silver trifluoroacetate on the TLC plate resulted in brown materials after UV laser irradiation. It was suggested that silver trifluoroacetate yielded Ag nanoparticles as brown materials after heating via laser irradiation. The nanoparticles behaved as an inorganic matrix and a source of Ag+ adduct in the analysis of PI oligomers. The use of organic matrices together with silver trifluoroacetate reduced the signal intensity of PI oligomers on MALDI-MS on a TLC plate. The separation of PI oligomers (polymerization degree, n = 5-11) by TLC resulted in a single elliptical spot without a clear separation after the chromatographic procedure. However, in MS imaging, differences in migration lengths based on degrees of polymerization were clearly observed and the degrees of polymerization were identified without comparison with standards.

Two-dimensional modeling of diamond growth by microwave plasma activated chemical vapor deposition: Effects of pressure, absorbed power and the beneficial role of nitrogen on diamond growth

A two-dimensional (2D(r, z)) self-consistent model developed and validated in previous studies of diamond deposition processes in microwave (MW) plasma activated chemical vapor deposition reactors is applied in a systematic study of ways in which the gas pressure (over the range p = 75–350 Torr) and absorbed power (P = 1–3 kW) affect the plasma parameters, species distributions and diamond deposition processes from a gas mixture (1%CH4/H2 with 60 ppm added N2) at substrate temperatures (Ts = 1073 and 1323 K) and diameters (ds = 32–100 mm). A more limited set of process conditions for a 0.006%N2/4%CH4/H2 gas mixture and Ts = 1038–1153 K are investigated also. The study traces variations in the global distributions of electron concentration, electron and gas temperature, absorbed power density, key species concentrations and the hydrocarbon interconversion reactions, with particular focus on the radial profiles of CH3 radical and H atom concentrations just above the substrate and on predicted diamond growth rates, G(r). The results and the trends revealed when varying p and P should help guide future optimizations of deposition regimes. The absorbed power density is shown to exhibit quite steep gradients in both the radial (r) and axial (z) directions. This, and the finding of significant power absorption beyond the glowing plasma region, limits the utility of the oft-quoted ‘averaged power density’ as a parameter. The modeling also highlights the essential 2D character of the hydrocarbon interconversion and diffusion transfer processes, which challenges the applicability of any 1D modeling of such MW plasmas. Trace additions of N2 to a MW plasma activated CH4/H2 gas mixture have negligible effect on the plasma parameters or chemistry yet are known to boost the diamond growth rate. A semi-empirical expression for G(r) is developed further to explicitly include the effects of added N2 and a new mechanistic picture presented to account for the observed N-induced enhancements in G. This picture invokes stable moieties such as that formed by CH2 insertion into a CN dimer bond on the 2 × 1 reconstructed (100) diamond surface as ‘anchor’ sites that enable shorter CH2 surface migration lengths and more step-edges for irreversible incorporation of such migrating groups on the growing diamond surface.

Flexible Riser Tensile Armor Modelling Method and Application to Fatigue Analysis

In this paper, we present a new stress calculation method for flexible structures, particularly, tensile armors, and apply it to flexible riser fatigue analysis. The method is based on a 3-dimensional curved bar theory. First, the tensile armor center line was described as a cylindrical helix curve; its bent curve length and bending migration length were derived and studied under different friction scenarios. Second, the tensile and bending stiffness was derived with consideration of more accurate shape parameters and the frictional hysteretic effect, and verified through FEA analysis results. Third, we presented the stress calculation formula for tensile armor under tension and bending load. All stress components were considered, including tensile, bending and shear stresses. Fourth, the method was benchmarked with published experimental results on a flexible prototype tension and bending tests, and comparisons showed general agreements. Fifth, the method was applied to an in-service 8″ flexible riser for fatigue assessment and lifetime extension evaluation, and showed the flexible riser has sufficient remaining fatigue life, and is suitable to continue its service under the current operating conditions. Last, conclusions were drawn. We concluded that the presented tensile armor stress calculation method and modelling techniques are valid for flexible riser fatigue analysis. This method is time efficient, and can be implemented into other multi-scale models for riser dynamic analysis. It is also applicable to other similar helix structure stress analysis, such as wire ropes, submarine hoses, and subsea umbilicals.

326-OR: Rod Photoreceptor Contribution to Inflammation and Angiogenesis in Diabetic Retinopathy

Purpose: Rod photoreceptors (rods) are the most numerous and metabolically active retinal cells, and are susceptible to metabolic stress in response to hyperglycemia. Yet the role of rods in diabetic retinopathy (DR) is controversial. This study aims to investigate if rods exposed to high glucose can trigger inflammatory and angiogenic responses in Müller glia (MG) and retinal microvascular endothelial cells (RMEC). Methods: The streptozocin-induced (STZ) model was used at 10 weeks of diabetes. Transcriptomic shifts in rods were analyzed by RNAseq. The mediators produced by rods were analyzed by multiplex ELISA. The effect of rod-produced mediators on RMEC permeability was assessed. Angiogenic responses of RMECs treated with rod-produced mediators were evaluated by proliferation, migration, and tube formation assays. The effect of rods on proangiogenic mediator production by RMECs and MG was evaluated by western blot. Results: Diabetes induced upregulation of transcripts for tnf (3-fold, P=0.006) and il1a (2.2-fold, P=0.001) in rods. Primary rod cultures treated with 25 mM D-glucose (high glucose) produced increased levels of VEGF (2.5-fold, p<0.05), TNF-α (2.4-fold, p<0.05), and IL-6 (2-fold, p<0.05) compared to rods treated with 5 mM D-glucose (normal glucose), or with 25 mM L-glucose (osmotic control). The mediators produced by rods treated with high glucose elicited increased RMEC proliferation (2.5 fold, p<0.001), RMEC migration (2-fold, p<0.001), and RMEC tube lengths (1.9-fold, p<0.001). The rod-produced mediators induced RMEC secretion of matrix metalloproteinase 2 (MMP-2) (8-fold increase, p<0.001) and of MMP-9 (5-fold increase, p<0.001). MG treated with rod-produced mediators increased their production of VEGF (4-fold, p<0.001) and of MMP-9 (5-fold, p<0.001). Conclusion: Rods in hyperglycemic conditions produce mediators that increase RMEC permeability, proliferation, migration, and branching and induce a proangiogenic secretory shift in RMEC and MG. Disclosure I.De la huerta: None. J.M.Poloway: None. V.Reddy: None. J.S.Penn: None. Funding National Institutes of Health (K08EY032620); International Retinal Research Foundation; Knights Templar Eye Foundation

A new neutron-gamma porosity measurement method for pulsed neutron logging tools

As an alternative method for the compensated neutron porosity measurement method, the neutron-gamma porosity measurement method is widely used in cased holes. However, the neutron-gamma porosity measurement method has some problems, such as the lack of detailed theoretical analysis and low sensitivity in high-porosity formations. The purpose of this paper is to clarify the theory of neutron-gamma porosity measurement, improve the measurement sensitivity, and eliminate the effects of environmental factors. Based on the neutron diffusion theory and the gamma transport theory, the distribution of capture gamma rays is described. A new neutron-gamma porosity measurement method is developed based on inelastic and capture gamma-ray distribution. The applicability of the new method in different environments is analyzed using the Monte Carlo method, and the effectiveness of this method is verified using the synthetic model. The results indicate that the capture gamma-ray ratio is only related to the source-detector distance, gamma-ray attenuation length, and neutron migration length. By combining density, different neutron cross sections, inelastic gamma-ray count ratio, and capture gamma-ray count ratio, the parameter secondary gamma-ray hydrogen index (SGH) related to hydrogen index can be extracted. The dynamic range of SGH is much higher than thermal neutron count ratio and the capture gamma-ray count ratio. The errors in porosity calculation by this method under different borehole and lithologic conditions are generally less than 2 pu. The calculation error of this method is close to that of the compensated neutron porosity measurement method. In addition, the applicability of the new method is analyzed without density data, and the results indicate that the calculation results are basically consistent with the results of calculation with density data. The new method has great potential for extensive applications in cased holes or open holes as an alternative for the compensated neutron porosity logging measurement method.

Poly-D,L-Lactic Acid Stimulates Angiogenesis and Collagen Synthesis in Aged Animal Skin.

Angiogenesis promotes rejuvenation in multiple organs, including the skin. Heat shock protein 90 (HSP90), hypoxia-inducible factor-1 alpha (HIF-1α), and vascular endothelial growth factor (VEGF) are proangiogenic factors that stimulate the activities of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and extracellular signal-regulated kinase 1/2 (ERK1/2). Poly-D,L-lactic acid (PDLLA), polynucleotide (PN), and calcium hydroxyapatite (CaHA) are dermal fillers that stimulate the synthesis of dermal collagen. However, it is not yet known whether these compounds promote angiogenesis, which leads to skin rejuvenation. Here, we evaluated whether PDLLA, PN, and CaHA stimulate angiogenesis and skin rejuvenation using H2O2-treated senescent macrophages and endothelial cells as an in vitro model for skin aging, and we used young and aged C57BL/6 mice as an in vivo model. Angiogenesis was evaluated via endothelial cell migration length, proliferation, and tube formation after conditioned media (CM) from senescent macrophages was treated with PDLLA, PN, or CaHA. Western blot showed decreased expression levels of HSP90, HIF-1α, and VEGF in senescent macrophages, but higher expression levels of these factors were found after treatment with PDLLA, PN, or CaHA. In addition, after exposure to CM from senescent macrophages treated with PDLLA, PN, or CaHA, senescent endothelial cells expressed higher levels of VEGF receptor 2 (VEGFR2), PI3K, phosphorylated AKT (pAKT), and phosphorylated ERK1/2 (pERK1/2) and demonstrated greater capacities for cell migration, cell proliferation, and tube formation. Based on the levels of 4-hydroxy-2-nonenal, the oxidative stress level was lower in the skin of aged mice injected with PDLLA, PN, or CaHA, while the tumor growth factor (TGF)-β1, TGF-β2, and TGF-β3 expression levels; the density of collagen fibers; and the skin elasticity were higher in the skin of aged mice injected with PDLLA, PN, or CaHA. These effects were greater in PDLLA than in PN or CaHA. In conclusion, our results are consistent with the hypothesis that PDLLA stimulates angiogenesis, leading to the rejuvenation of aged skin. Our study is the first to show that PDLLA, PN, or CaHA can result in angiogenesis in the aged skin, possibly by increasing the levels of HSP90, HIF-1α, and VEGF and increasing collagen synthesis.

Peptide RL-QN15 promotes regeneration of epidermal nerve fibers and recovery of sensory function in diabetic skin wounds.

Epidermal nerve fiber regeneration and sensory function are severely impaired in skin wounds of diabetic patients. To date, however, research on post-traumatic nerve regeneration and sensory reconstruction remains scarce, and effective clinical therapeutics are lacking. In the current study, localized treatment with RL-QN15, considered as a drug candidate for intervention in skin wounds in our previous research, accelerated the healing of full-thickness dorsal skin wounds in diabetic mice and footpad skin wounds in diabetic rats. Interestingly, nerve density and axonal plasticity in the skin wounds of diabetic rats and mice, as well as plantar sensitivity in diabetic rats, were markedly enhanced by RL-QN15 treatment. Furthermore, RL-QN15 promoted the proliferation, migration, and axonal length of neuron-like PC12 cells, which was likely associated with activation of the phosphatidylinositol-3 kinase/protein kinase B (PI3K/Akt) signaling pathway. The therapeutic effects of RL-QN15 were partially reduced by blocking the PI3K/Akt signaling pathway with the inhibitor LY294002. Thus, RL-QN15 showed positive therapeutic effects on the distribution of epidermal nerve fibers and stimulated the recovery of sensory function after cutaneous injury. This study lays a solid foundation for the development of RL-QN15 peptide-based therapeutics against diabetic skin wounds.

Host Migration and Size Do Not Influence the Prevalence of Most Chewing Lice (Phthiraptera: Amblycera and Ischnocera) on Shorebirds (Aves: Charadriiformes) across the World

Patterns of prevalence in chewing lice (Phthiraptera) on wild birds are poorly known, as are the underlying factors that influence these patterns. Here, we analyze a data set consisting of published prevalence data of lice on shorebirds, as well as new prevalence data from shorebirds examined in Australia, Canada, China, Japan, and Sweden between 2007 and 2020. In total, prevalence data from 10 genera of lice from over 110 host species were included, including all major families of shorebirds. Using a generalized linear mixed model, we examine how the prevalence of lice of different genera varies between different sets of birds, focusing on two factors associated with migration (migration length and migration route). We found that host body size does not influence prevalence of lice in the Charadriiformes for any of the four most common and widely distributed louse genera (Actornithophilus, Austromenopon, Quadraceps, and Saemundssonia). Moreover, neither of the two migration variables showed any statistically significant correlations with prevalence, except for the genus Saemundssonia in which the prevalence of lice on short-distance migrants was significantly higher than on intermediate- and long-distance migrants. We also present 15 new records of chewing lice for China and 12 for Australia.

Pre-analytical sample handling effects on tear fluid protein levels

Tear fluid is emerging as a source of non-invasive biomarkers, both for ocular and systemic conditions. Accurate quantification of tear proteins can be improved by standardizing methods to collect and process tear fluid. The aim of this study was to determine sample handling factors that may influence the tear protein biomarker profile. Tear fluid was collected using Schirmer’s strips. Tear proteins were extracted by elution through centrifugation. Total protein content was determined using the bicinchoninic acid assay. Key concepts that apply to the entire sample processing cycle are tear sampling, tear storage, protein extraction and data normalization. Differences in wetting or migration length were observed between Schirmer’s strips from different manufacturers, and between protein-free and protein-rich solutions. One unit of migration length (mm) did not correspond to one unit of volume (µL). A positive correlation (r = 0.6671, p < 0.0001) was observed between migration length and total tear protein content. The most beneficial storage conditions were strips that were not stored (+ 21.8%), or underwent ‘wet’ storage (+ 11.1%). Protein recovery was the highest in 400 µL extraction buffer and independent of protein molecular weight. This study helps to explain inter- and intra-variability that is often seen with tear biomarker research. This information is critical to ensure accuracy of test results, as tear biomarkers will be used for patient management and in clinical trials in the near future. This study also highlights the need for standardization of Schirmer’s strip manufacturing, tear fluid processing and analyte concentration normalization.

Migration-Enhanced Metal–Organic Chemical Vapor Deposition of Wafer-Scale Fully Coalesced WS2 and WSe2 Monolayers

Metal–organic chemical vapor deposition (MOCVD) is widely employed for the wafer-scale synthesis of transition metal dichalcogenide (TMDC) monolayers (MLs). Despite large efforts devoted to understanding the intricate nucleation and lateral growth mechanisms of TMDCs, little attention has been paid to the migration of adatoms on the top of an ML and its influence on parasitic/premature bilayer (BL) nucleation. In this work, using a commercial multi-wafer MOCVD platform, a novel two-stage migration-enhanced MOCVD process is introduced to realize the deposition of wafer-scale fully coalesced tungsten disulfide (WS2) and tungsten diselenide (WSe2) MLs with only sparse BL nucleation in a reasonable deposition time. With the WS2 ML coverage exceeding 99% on 2 in. sapphire substrates within 3 h, BL coverage is suppressed to ∼15%. Following the same migration enhancement approach, WSe2 MLs are synthesized in 90 min with <20% BL coverage. The migration of W adatoms on the already formed stable WS2 (or WSe2) ML domains is promoted by ramping down the delivery of the tungsten precursor. From the qualitative analysis of the nanomorphology, the migration length of W adatoms is estimated to be ≤100 nm. This approach can be seen as a reliable and solid basis for the development of future large-scale TMDC ML deposition techniques.

β‐Ketoenamine‐Linked Covalent Organic Framework with Co Intercalation: Improved Lithium‐Storage Properties and Mechanism for High‐Performance Lithium‐Organic Batteries

AbstractAs a new kind of crystalline porous polymers, covalent organic frameworks (COFs) exhibit great potential as electrode materials for rechargeable metal‐ion batteries due to their stable and adjustable structure, high porosity and abundant electrochemical active centers. In this paper, facile one‐step synthesis process is proposed to obtain the cobalt ion intercalated two‐dimensional β‐ketoenamine‐linked COF (Co−DAAQ−TFP‐COF, denoted as Co‐COF). The intercalation of Co ion in adjacent two layered structure of COF via coordination effects can activate the Li+ storage ability of aromatic ring in the original COF, greatly improve the utilization of redox active sites, shorten the migration length of electrons and ions, and promote fast lithium reaction kinetics. Adopted as the anode for lithium‐ion batteries, substantial improvement on the reversible capacity and cycling performance can be achieved for the obtained Co intercalated COF electrode (780 mAh g−1 after 200 cycles at 100 mA g−1) compared to original COF electrode (120 mAh g−1 under the same condition). The two‐dimensional COF materials with morphology justification and/or performance improvement via metal ion intercalation would promote the application of COF related electrodes for other energy‐storage fields.

Reactive transport simulations of uranium migration in the Opalinus Clay depend on ion speciation governed by underlying thermodynamic data

Abstract. Safety assessments must demonstrate that radionuclides in potential disposal sites are retained within the containment providing rock zone. The impact of thermodynamic data on calculated migration lengths resulting from reactive transport simulations is quantified for the example of uranium in the hydrogeological system of the Opalinus Clay at Mont Terri. In this geochemical system, speciation is controlled by the calcite-carbonate-ion system. Aqueous uranium is mainly present as U(VI) as ternary complexes with calcium or magnesium together with carbonate. Previous simulations using the first NEA update of thermodynamic data for uranium indicated that the anionic complex CaUO2(CO3)32- is the predominant species with a maximum migration distance of 50 m after one million years. The NEA published an update of the thermodynamic data for uranium, what, in turn, changes the predominant species from anionic to almost only the neutral ternary complex Ca2UO2(CO3)3. With identical simulations, except for the application of the second NEA update, a maximum distance of 80 m was obtained. This can be attributed to a decrease in sorption capacity due to a stronger complexation of uranium with calcium and carbonate. Therefore, the impact of the change in the underlying thermodynamic data can be quantified with +30 m. Our work clearly shows how sensitive migration lengths resulting from reactive transport simulations are to the model conceptualisation and selection of underlying data. Consequently, the compilation and further development of data sets and a site specific investigation are indispensable for reliable outcomes of transport simulations, and thus of performance assessments.