Design of an apparatus for measuring tool/fabric and fabric/fabric friction of woven-fabric composites during the thermostamping process

The thermostamping of prepreg woven fabrics shows promise as a low-cost high-volume manufacturing process for composite parts. One concern associated with the process is the unwanted formation of defects in the form of fabric wrinkling. This wrinkling can be prevented during the thermostamping process by inducing in-plane forces through the use of one or more metal binder rings. However, if the in-plane forces are too low, then the fabric may wrinkle as the fabric conforms to the shape of the punch, and conversely, if the in-plane forces are too high, then the yarns in the fabric can separate and the fabric may tear and yarns can break. The in-plane forces are a result of the friction between the fabric and the metal binder rings. As the fabric slides over the surfaces of the punch and die, further friction is induced between the metal tooling and the fabric part. In addition, most composite parts consist of multiple layers, and therefore as the fabric is drawn into the die adjacent layers of fabric may slide relative to one another. Thus, the friction at the tool/fabric interface and the interlaminar friction must be understood and quantified to predict part quality as a function of the processing parameters. In this paper, the design and implementation of a load-control test apparatus used to measure the friction between the tool and the fabric and between adjacent layers of fabric during a composite forming process is presented.     

Development of an integrated approach for the stability testing of flavonoids and ascorbic acid in powders

An integrated approach for determining the stability of flavonoids and ascorbic acid in powders was developed. A rapid analyte solubility procedure was used to decide whether HPLC, GLC, or NMR would best serve to measure the stability of each flavonoid. Both the flavonoid under study and ascorbic acid were measured in one analysis with any of the determinative methods. Seventeen flavonoids of differing types, as well as ascorbic acid, were evaluated to establish the approach. The effects of storage relative humidity (RH) on the stability of several flavonoid powders with and without ascorbic acid were then determined. Quercetin, luteolin, taxifolin, naringenin, and naringin were stable for up to 8 weeks in RHs up to 98%, and ascorbic acid was significantly destroyed in the presence of quercetin, luteolin, and taxifolin at 98% RH. Both grape anthocyanins and ascorbic acid were unstable in the presence of each other at 98% RH. The integrated approach could be used for shelf-life testing of powdered flavonoids under a variety of storage conditions.     

Integration of a Chemical‐Responsive Hydrogel into a Porous Silicon Photonic Sensor for Visual Colorimetric Readout

The incorporation of a chemo‐responsive hydrogel into a 1D photonic porous silicon (PSi) transducer is demonstrated. A versatile hydrogel backbone is designed via the synthesis of an amine‐functionalized polyacrylamide copolymer where further amine‐specific biochemical reactions can enable control of cross‐links between copolymer chains based on complementary target–probe systems. As an initial demonstration, the incorporation of disulfide chemistry to control cross‐linking of this hydrogel system within a PSi Bragg mirror sensor is reported. Direct optical monitoring of a characteristic peak in the white light reflectivity spectrum of the incorporated PSi Bragg mirror facilitates real‐time detection of the hydrogel dissolution in response to the target analyte (reducing agent) over a timescale of minutes. The hybrid sensor response characteristics are shown to systematically depend on hydrogel cross‐linking density and applied target analyte concentration. Additionally, effects due to responsive hydrogel confinement in a porous template are shown to depend on pore size and architecture of the PSi transducer substrate. Sufficient copolymer and water is removed from the PSi transducer upon dissolution and drying of the hydrogel to induce color changes that can be detected by the unaided eye. This highlights the potential for future development for point‐of‐care diagnostic biosensing.     

The Absence of Extracellular Cold-Inducible RNA-Binding Protein (eCIRP) Promotes Pro-Angiogenic Microenvironmental Conditions and Angiogenesis in Muscle Tissue Ischemia

Extracellular Cold-inducible RNA-binding protein (eCIRP), a damage-associated molecular pattern, is released from cells upon hypoxia and cold-stress. The overall absence of extra- and intracellular CIRP is associated with increased angiogenesis, most likely induced through influencing leukocyte accumulation. The aim of the present study was to specifically characterize the role of eCIRP in ischemia-induced angiogenesis together with the associated leukocyte recruitment. For analyzing eCIRPs impact, we induced muscle ischemia via femoral artery ligation (FAL) in mice in the presence or absence of an anti-CIRP antibody and isolated the gastrocnemius muscle for immunohistological analyses. Upon eCIRP-depletion, mice showed increased capillary/muscle fiber ratio and numbers of proliferating endothelial cells (CD31⁺/CD45⁻/BrdU⁺). This was accompanied by a reduction of total leukocyte count (CD45⁺), neutrophils (MPO⁺), neutrophil extracellular traps (NETs) (MPO⁺CitH3⁺), apoptotic area (ascertained via TUNEL assay), and pro-inflammatory M1-like polarized macrophages (CD68⁺/MRC1⁻) in ischemic muscle tissue. Conversely, the number of regenerative M2-like polarized macrophages (CD68⁺/MRC1⁺) was elevated. Altogether, we observed that eCIRP depletion similarly affected angiogenesis and leukocyte recruitment as described for the overall absence of CIRP. Thus, we propose that eCIRP is mainly responsible for modulating angiogenesis via promoting pro-angiogenic microenvironmental conditions in muscle ischemia.     

New electromagnetic shielding materials based on viscose‐carbon nanotubes composites

A convenient approach for the preparation of cellulose ‐ carbon nanotubes (CNT) hybrid materials owning electromagnetic shielding properties, based on viscose (V) and TEMPO‐oxidized viscose fibers (VO) is proposed. Viscose ‐ carbon nanotubes (V‐CNT) and TEMPO‐oxidized viscose ‐ carbon nanotubes (VO‐CNT) composites were prepared by embedding carbon nanotubes on the surface of two types of cellulose fibers, that is, viscose and its C₆‐oxidized derivative. The chemical composition, morphology, and thermal stability of the prepared hybrid materials were thoroughly investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analyses. Moreover, electrical properties of the original and composite fibers were assessed. POLYM. ENG. SCI., 59:1499–1506 2019. © 2019 Society of Plastics Engineers     

Rumen-protected B vitamin complex supplementation during the transition period and early lactation alters endometrium mRNA expression on day 14 of gestation in lactating dairy cows

Greater metabolic demands in high-producing dairy cows are believed to be a cause of sub-fertility in these animals. Previously, supplementation with vitamin B complex molecules has shown benefits in improving milk production, health, and reproductive efficiency of dairy cows. The primary aim of this project was to determine the effects of rumen-protected vitamin B complex supplementation of 100 g of Transition VB (Jefo, St. Hyacinthe, QC, Canada) and 4 g of Lactation VB (VB; Jefo), during the transition and early lactation periods, respectively, compared with a control diet containing no supplementation on d 14 endometrial outcomes of pregnancy. In the vitamin B supplemented cows, we expect to see a change in the mark-up of endometrial genes important for embryo survival before implantation. Multiparous Holstein cows were enrolled into the study 3 wk before parturition and were randomly assigned to either the VB or control treatment. Twice-a-week blood samples, weekly milk samples, and daily feed intake were collected. Cows were enrolled onto a double-ovsynch protocol at 33 ± 3 d postpartum and inseminated by timed artificial insemination. Milk production and components, concentrations of BHB, haptoglobin, and progesterone in serum, and ovarian dynamics were also measured, but no treatment effect was observed. The uterus was flushed on d 14 after artificial insemination (around 72 DIM) for conceptus collection, and endometrial samples were collected at the same time. Overall, 42 cows were flushed and 13 embryos were collected. Analysis of mRNA expression of genes related to embryo development, immune system, adhesion, and regulation of vitamin B molecules showed that OXTR, MUC5B, MUC1, IL1B, SPP, TRD, FZD8, and FOLR1 genes were significantly upregulated in the VB group. Vitamin B supplementation had no effect on the size of the embryo and ovulatory follicle or corpus luteum diameter at embryo collection. In conclusion, the benefits of strategic dietary VB supplementation during the transition and early lactation might be directly linked to endometrial functions required for embryo survival during the peri-implantation period.     

Rhodamine-loaded poly(lactic-co-glycolic acid) nanoparticles for investigation of in vitro interactions with breast cancer cells

Nanoparticle-based drug delivery systems are considered promising for the delivery of imaging agents and drugs for the detection and treatment of illnesses, including cancer. Investigation of nanoparticle interactions with the diseased cells can lead to better designs. In this work, poly(lactic-co-glycolic acid) nanoparticles loaded with rhodamine 6G were prepared by nanoprecipitation with high encapsulation efficiency. In vitro release studies demonstrated that rhodamine escaped from the nanoparticles at a very slow rate at physiological pH, thus making it ideal for imaging studies. At acidic pH this agent was released quickly, suggesting charge interactions between the polymer and rhodamine. Microscopy and flow cytometry studies show higher uptake in MDA-MB-231 breast cancer cells when exposed to rhodamine-loaded nanoparticles than to rhodamine in solution.     

Pathways for the anaerobic microbial debromination of polybrominated diphenyl ethers

The debromination pathways of seven polybrominated diphenyl ethers (PBDEs) by three different cultures of anaerobic dehalogenating bacteria were investigated using comprehensive two-dimensional gas chromatography (GC x GC). The congeners analyzed were the five major components of the industrially used octa-BDE mixture (octa-BDEs 196, 203, and 197, hepta-BDE 183, and hexa-BDE 153) as well as the two most commonly detected PBDEs in the environment, penta-BDE 99 and tetra-BDE 47. Among the dehalogenating cultures evaluated in this study were a trichloroethene-enriched consortium containing multiple Dehalococcoides species, and two pure cultures, Dehalobacter restrictus PER-K23 and Desulfitobacterium hafniense PCP-1. PBDE samples were analyzed by GC x GC coupled to an electron capture detector to maximize separation and identification of the product congeners. All studied congeners were debrominated to some extent by the three cultures and all exhibited similar debromination pathways with preferential removal of para and meta bromines. Debromination of the highly brominated congeners was extremely slow, with usually less than 10% of nM concentrations of PBDEs transformed after three months. In contrast, debromination of the lesser brominated congeners, such as penta 99 and tetra 47, was faster, with some cultures completely debrominating nM levels of tetra 47 within weeks.