Spectral dependence of transmission losses in high-index polymer coated no-core fibers

A high-index polymer coated no-core fiber (PC-NCF) is effectively a depressed core fiber, where the light is guided by the anti-resonant, inhibited coupling and total internal reflection effects and the dispersion diagram shows periodic resonant and anti-resonant bands. In this paper, the transmission spectra of the straight and bent PC-NCFs (length > 5 cm) are measured and analyzed from a modal dispersion perspective. For the purpose of the study, the PC-NCFs are contained within a fiber hetero-structure using two single-mode fiber (SMF) pigtails forming a SMF-PC-NCF-SMF structure. The anti-resonance spectral characteristics are suppressed by the multimode interference in the PC-NCF with a short fiber length. The increase of the length or fiber bending (bend radius > 28 cm) can make the anti-resonance dominate and result in the periodic transmission loss dips and variations in the depth of these loss dips, due to the different modal intensity distributions in different bands and the material absorption of the polymer. The PC-NCFs are expected to be used in many devices including curvature sensors and tunable loss filters, as the experiments show that the change of loss dip around 1550 nm is over 31 dB and the average sensitivity is up to 14.77 dB/m-1 in the bend radius range from to 47.48 cm. Our study details the general principles of the effect of high-index layers in the formation of the transmission loss dips in fiber optics

Oxide Dispersion Strengthened (ODS) SS316L Prepared by Laser Powder Bed Fusion (L-PBF): Analysis of Microstructure and Hardness Properties

In this paper, dense oxide dispersion-strengthened (ODS) SS316L with 0.5 wt.% Y2O3 was fabricated using nano-Y2O3-embedded spherical SS316L powder via laser powder bed fusion (LPBF). The molten pool, oxide dispersion, cellular structure, and microhardness of the as-printed ODS SS316L were investigated through optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-Ray Spectroscopy (EDX), and Vickers hardness testing, respectively. The results reveal a uniform dispersion of Y-rich nanoparticles in as-printed ODS SS316L, contributing to the development of a fine-grain structure in the as-printed ODS SS316L. A wide and shallow molten pool was observed in as-printed ODS SS316L, and enhanced microhardness was observed in ODS SS316L compared to pristine SS316L. The effects of Y2O3 on microstructure evolution and reinforcing mechanisms of microhardness are discussed.Mechanical Engineerin

HECT, UBA and WWE domain containing 1 represses cholesterol efflux during CD4+ T cell activation in Sjögren’s syndrome

Introduction: Sjögren’s syndrome (SS) is a chronic autoimmune disorder characterized by exocrine gland dysfunction, leading to loss of salivary function. Histological analysis of salivary glands from SS patients reveals a high infiltration of immune cells, particularly activated CD4+ T cells. Thus, interventions targeting abnormal activation of CD4+ T cells may provide promising therapeutic strategies for SS. Here, we demonstrate that Hect, uba, and wwe domain containing 1 (HUWE1), a member of the eukaryotic Hect E3 ubiquitin ligase family, plays a critical role in CD4+ T-cell activation and SS pathophysiology.Methods: In the context of HUWE1 inhibition, we investigated the impact of the HUWE1 inhibitor BI8626 and sh-Huwe1 on CD4+ T cells in mice, focusing on the assessment of activation levels, proliferation capacity, and cholesterol abundance. Furthermore, we examined the therapeutic potential of BI8626 in NOD/ShiLtj mice and evaluated its efficacy as a treatment strategy.Results: Inhibition of HUWE1 reduces ABCA1 ubiquitination and promotes cholesterol efflux, decreasing intracellular cholesterol and reducing the expression of phosphorylated ZAP-70, CD25, and other activation markers, culminating in the suppressed proliferation of CD4+ T cells. Moreover, pharmacological inhibition of HUWE1 significantly reduces CD4+ T-cell infiltration in the submandibular glands and improves salivary flow rate in NOD/ShiLtj mice.Conclusion: These findings suggest that HUWE1 may regulate CD4+ T-cell activation and SS development by modulating ABCA1-mediated cholesterol efflux and presents a promising target for SS treatment

An empirical Bayes model for gene expression and methylation profiles in antiestrogen resistant breast cancer

<p>Abstract</p> <p>Background</p> <p>The nuclear transcription factor estrogen receptor alpha (ER-alpha) is the target of several antiestrogen therapeutic agents for breast cancer. However, many ER-alpha positive patients do not respond to these treatments from the beginning, or stop responding after being treated for a period of time. Because of the association of gene transcription alteration and drug resistance and the emerging evidence on the role of DNA methylation on transcription regulation, understanding of these relationships can facilitate development of approaches to re-sensitize breast cancer cells to treatment by restoring DNA methylation patterns.</p> <p>Methods</p> <p>We constructed a hierarchical empirical Bayes model to investigate the simultaneous change of gene expression and promoter DNA methylation profiles among wild type (WT) and OHT/ICI resistant MCF7 breast cancer cell lines.</p> <p>Results</p> <p>We found that compared with the WT cell lines, almost all of the genes in OHT or ICI resistant cell lines either do not show methylation change or hypomethylated. Moreover, the correlations between gene expression and methylation are quite heterogeneous across genes, suggesting the involvement of other factors in regulating transcription. Analysis of our results in combination with H3K4me2 data on OHT resistant cell lines suggests a clear interplay between DNA methylation and H3K4me2 in the regulation of gene expression. For hypomethylated genes with alteration of gene expression, most (~80%) are up-regulated, consistent with current view on the relationship between promoter methylation and gene expression.</p> <p>Conclusions</p> <p>We developed an empirical Bayes model to study the association between DNA methylation in the promoter region and gene expression. Our approach generates both global (across all genes) and local (individual gene) views of the interplay. It provides important insight on future effort to develop therapeutic agent to re-sensitize breast cancer cells to treatment.</p

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals &lt;1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Development of Oxide Dispersion Strengthening (ODS) Alloys Powder for Additive Manufacturing

Additive manufacturing (AM) fabricated oxide dispersion strengthened (ODS) alloys are given high expectations for critical structural components such as the first stage turbine blade for their excellent creep strength and oxidation resistance compared to superalloys. However, the powder feedstock processing is still an open question since current state-of-the-art processes are not capable of achieving ultrafine strengthening elements such as Y2O3 in powder which leads to agglomeration issues in as-consolidated alloys. In this research, the oxidation behavior and stability of ultrafine oxide in AM-printed alloys using mechanically alloyed powders were evaluated at 1100 oC. In addition, a novel powder processing method was developed based on the mechanism of strengthening element (i.e.Y2O3) evolution in powder precursor and as-consolidated alloys with the benefit of grain refinement and improved mechanical property and oxidation resistance. In this study, it was found that 1) the size of Y2O3 in powder precursor is of importance to achieving ultrafine Y-rich nanoparticles, both plate-like and spherical nanoparticles formed in as-consolidated alloys using mechanically alloyed powder due to non-uniform convection of molten pool, 2) nanoparticles stabilized under the protection of Al2O3 at 1100 oC and spallation of oxide layer occurs in oxide mixture, 3) high energy mixing of gas atomized alloy powder and Y2O3 can generate ultrafine nanoparticles in powder and as-printed alloys attributed to the functional composite layer formation with surface deformation in metallic powder, 4) ultrafine Y2O3 and coarser Y-Al-rich oxides (nm) were observed in AM-printed IN718, 5) exceptional strength and ductility of AM-printed ODS IN718 alloy are attributed to fine structure and oxides strengthening effects, and 6) adding 1 wt.% Y2O3 can effectively refine the sub-grain of SS316L alloy with improved Vickers hardness (HV1) from 177 to 240. The output of this research demonstrates the mechanism of Y2O3 evolution in powder and AM process, and provides one way to cost-effective fabricate ultrafine oxide dispersed alloys with fine grain structure and improved mechanical properties

Phase-Extraction-Based MFL Testing for Subsurface Defect in Ferromagnetic Steel Plate

Magnetic flux leakage (MFL) based on phase extraction for detecting the subsurface defects in ferromagnetic steel plate was investigated. The relationship between electromagnetic field phase and the subsurface defect was analyzed. Low-frequency alternating current (AC) excitation source and high-power magnetizer arrangement with Hall sensor were used to increase the skin depth of the MFL. Experiments results showed that 12 mm deep subsurface defect can be detected by using the phase extraction means, which is about two times higher than that by using the amplitude method