The effect of cellulose nanocrystals on latex and adhesive properties in emulsion- based polymer nanocomposites

Pressure sensitive adhesives (PSAs) adhere quickly and firmly to surfaces with the application of light pressure, and can be removed without leaving a residue. Their mechanical performance is measured by tack, peel strength and shear strength. A balanced combination between the three mechanical performance measurements depends on the specific end-use application and is challenging to achieve. This is particularly so when replacing solvent-based technologies with more sustainable, water-based (i.e., emulsion polymerization) technologies. PSAs synthesized using emulsion polymerization tend to have a lower shear strength due to poor gel network formation. As a result, conventional emulsion-based PSAs suffer from the inability to increase certain adhesive properties (e.g., tack and peel strength) while simultaneously increasing shear strength. Nanomaterials are often used in polymer composites to improve polymer properties (e.g., tensile strength). They are particularly effective in low quantities (e.g., \u3c2 \u3ewt.%) because of their high surface area. Cellulose nanocrystals (CNCs) are a “green alternative” to common nanomaterials and are isolated from natural cellulose. CNCs have been used more commonly, in the past, as rheological modifiers and interface stabilizers.[1] Because CNCs form colloidally stable dispersions in water, they can be incorporated/processed in water-based systems, eliminating the need for organic solvents.[2] The most common method to produce CNCs is through acid hydrolysis with sulfuric acid; this process preferentially degrades the disordered cellulose regions and leaves behind the crystalline CNCs with grafted anionic sulfate half ester groups.[1] The resulting nanoparticles are whisker-shaped and have a high aspect ratio.[3] CNCs provide composite material reinforcement in the range of other nanomaterials. In the past, CNCs have been blended with polymers and significant strength improvements were noted.[4] Our studies demonstrate how to incorporate CNCs in a nanocomposite using an in situ semi-batch emulsion polymerization protocol.[5] PSA nanocomposite films were generated for a broad variety of copolymer systems including monomers such as iso-butyl acrylate, n-butyl acrylate, 2-ethyl hexyl acrylate, methyl methacrylate, styrene and vinyl acetate. In all cases, the monomer composition of the reaction formulations was manipulated to achieve a suitable range of polymer glass transition temperatures. CNC loadings were varied from 0 to 0.5 to 1 wt.% (based on monomer weight). The addition of CNC was shown to significantly and simultaneously increase tack, peel strength, and shear strength.[6] References [1] Dufresne, A., Nanocellulose, De Gruyter, Saint Martin D’Heres Cedex, France 2012. [2] Flauzino Neto, W. P., Mariano, M., da Silva, I. S. V., Silvério, H. A., Putaux, J.-L., Otaguro, H., Pasquini, D., Dufresne, A., Carbohydr. Polym. 2016, 153, 143. [3] Moon, R. J., Martini, A., Nairn, J., Simonsen, J., Youngblood, J., Chem. Soc. Rev., 2011, 40, 3941. [4] Rajisha, K. R., Maria, H. J., Pothan, L. A., Ahmad, Z., Thomas, S., Int. J. Biol. Macromol., 2014, 67, 147. [5] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Macromol. React. Eng., 2018, in press. [6] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Int. J. Adh. Adh. 2018, 81, 36-42

Pressure sensitive adhesives produced by in-situ emulsion polymerization of cellulose nanocrystal-poly(nBA-VAc)

Pressure sensitive adhesives (PSAs) are conventionally produced using a variety of polymerization methods such as emulsion, solution, or radiation curing. Environmental concerns favor the development of emulsion polymerization based PSAs.[1] However, maintaining and controlling the PSA properties achievable from solution polymerization in PSAs produced by emulsion polymerization remains challenging. Depending on the particular adhesive application, PSA properties are largely guided by the polymer glass transition temperature and the polymer microstructure. The latter is controlled in a variety of ways but typically via the addition of chain transfer agents and crosslinkers.[2] During the last decades, efforts in PSA property manipulation have included the preparation of nanocomposite latexes by introducing nanomaterials such as titanium dioxide, silica, and carbon nanotubes into the formulations.[3] On the other hand, utilizing cellulose nanocrystals (CNCs) as a sustainable source of reinforcement in polymers is emerging rapidly.[4] CNCs are the product of controlled hydrolysis of plant based tissues, through which crystalline domains of cellulose are isolated from the disordered parts of the raw material. High aspect ratio, surface activity and modulus, as well as non-toxic nature of CNCs make them ideal candidates for use in nanocomposite formulations. More recently, our group have prepared CNC nanocomposite PSAs which were revealed to significantly and simultaneously improve tack, peel strength and shear strength in the PSA films.[5] The ability to improve tack and peel strength without decreasing shear strength overcomes a major challenge in PSA formulation. We will present results from emulsion polymerization of n-butyl acrylate/vinyl acetate/CNC nanocomposite PSAs. We will identify the location of the CNCs relative to the latex particles and show their effect on latex viscosity, gel content, and PSA properties. The goal of these new results is to show how the manipulation of the reaction formulation (e.g., monomer feed ratio, surfactant type) will affect the distribution and relative location of the CNCs in the polymer latex and ultimately the PSA properties. [1] Jovanović, R., Dubé, M. A., J. Macromol. Sci., Part C, 44:1, 1-51, 2004. [2] Qie, L., Dubé, M. A., 46, 1225–1236, 2010. [3] Dastjerdi, Z., Cranston, E. D., Berry, R. Fraschini, C., Dubé, M. A., J. Matls. Sci., submitted January 2018. [4] Lee, K-Y., Aitomäki, Y., Berglund, L. A., Oksman, K., Bismarck, A., Compos. Sci. Technol. 105, 15–27, 2014. [5] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Macromol. React. Eng., 11, 1700013, 2017. [6] Dastjerdi, Z., Cranston, E. D., Dubé, M. A., Int. J. Adh. Adh., 81, 36-42, 201

Examining smoking and cessation during pregnancy among an Appalachian sample: a preliminary view

Background Several transitions that a woman experiences prenatally may influence her desire or ability to discontinue smoking. This study explores the role of smoking for young, Appalachian, nulliparous pregnant women and their plans for smoking during their pregnancies. Results The reports of women and their male partners were taken from baseline interviews conducted during the first trimester of pregnancy. Cigarette smoking appeared to be more than an isolated addictive activity; rather, smoking was interwoven in women\u27s social and personal realms, often changing as their perceptions of self changed. Women and their partners who continued to smoke appeared to be depressed, reject authority, and perceived little control over issues related to being pregnant. Conclusion These findings support the argument that standard substance use treatments and polices based on stages-of-change theories may not be effective for all individuals particularly those experiencing significant developmental changes in their lives. Greater success might be obtained from treatment programs designed to recognize the impact of these transitions as it relates to the substance use. The changing experiences of pregnant women in terms of their identity development, views of others, and their relationships have not been adequately addressed in existing cessation programs. Empirically-based interventions targeting these lifestyle characteristics may lead to increased cessation success among pregnant women

Berry-Enriched Diet in Salt-Sensitive Hypertensive Rats:Metabolic Fate of (Poly)Phenols and the Role of Gut Microbiota

Diets rich in (poly)phenols are associated with a reduced reduction in the incidence of cardiovascular disorders. While the absorption and metabolism of (poly)phenols has been described, it is not clear how their metabolic fate is affected under pathological conditions. This study evaluated the metabolic fate of berry (poly)phenols in an in vivo model of hypertension as well as the associated microbiota response. Dahl salt-sensitive rats were fed either a low-salt diet (0.26% NaCl) or a high-salt diet (8% NaCl), with or without a berry mixture (blueberries, blackberries, raspberries, Portuguese crowberry and strawberry tree fruit) for 9 weeks. The salt-enriched diet promoted an increase in the urinary excretion of berry (poly)phenol metabolites, while the abundance of these metabolites decreased in faeces, as revealed by UPLC–MS/MS. Moreover, salt and berries modulated gut microbiota composition as demonstrated by 16S rRNA analysis. Some changes in the microbiota composition were associated with the high-salt diet and revealed an expansion of the families Proteobacteria and Erysipelotrichaceae. However, this effect was mitigated by the dietary supplementation with berries. Alterations in the metabolic fate of (poly)phenols occur in parallel with the modulation of gut microbiota in hypertensive rats. Thus, beneficial effects of (poly)phenols could be related with these interlinked modifications, between metabolites and microbiota environments.C.B., C.N.d.S., C.O. were funded by ANR (ANR-13-ISV1-0001-01) and FCT (FCTANR/BEX-BCM/0001/2013). D.B. was funded by the Austrian Science Fund (FWF P26127-B20) and European Research Council (Starting Grant: FunKeyGut 741623). D.S. and A.F. acknowledge support from Scottish Government: Rural and Environment Science and Analytical Services. We also acknowledge the Investment for the Future program ANR-11-IDEX-0003-01 within the LABEX ANR-10-LABX-0033 (C.B., C.O.), Fundação para a Ciência e Tecnologia financial support of A.G. (SFRH/BD/103155/2014) and C.N.d.S. (IF/01097/2013). iNOVA4Health Research Unit (LISBOA-01-0145-FEDER-007344), which is cofounded by FCT through national funds, and by FEDER under the PT2020 Partnership Agreement, is acknowledged

Discovery of a mammalian splice variant of myostatin that stimulates myogenesis

Myostatin plays a fundamental role in regulating the size of skeletal muscles. To date, only a single myostatin gene and no splice variants have been identified in mammals. Here we describe the splicing of a cryptic intron that removes the coding sequence for the receptor binding moiety of sheep myostatin. The deduced polypeptide sequence of the myostatin splice variant (MSV) contains a 256 amino acid N-terminal domain, which is common to myostatin, and a unique C-terminus of 65 amino acids. Western immunoblotting demonstrated that MSV mRNA is translated into protein, which is present in skeletal muscles. To determine the biological role of MSV, we developed an MSV over-expressing C2C12 myoblast line and showed that it proliferated faster than that of the control line in association with an increased abundance of the CDK2/Cyclin E complex in the nucleus. Recombinant protein made for the novel C-terminus of MSV also stimulated myoblast proliferation and bound to myostatin with high affinity as determined by surface plasmon resonance assay. Therefore, we postulated that MSV functions as a binding protein and antagonist of myostatin. Consistent with our postulate, myostatin protein was co-immunoprecipitated from skeletal muscle extracts with an MSV-specific antibody. MSV over-expression in C2C12 myoblasts blocked myostatin-induced Smad2/3-dependent signaling, thereby confirming that MSV antagonizes the canonical myostatin pathway. Furthermore, MSV over expression increased the abundance of MyoD, Myogenin and MRF4 proteins (P,0.05), which indicates that MSV stimulates myogenesis through the induction of myogenic regulatory factors. To help elucidate a possible role in vivo, we observed that MSV protein was more abundant during early post-natal muscle development, while myostatin remained unchanged, which suggests that MSV may promote the growth of skeletal muscles. We conclude that MSV represents a unique example of intra-genic regulation in which a splice variant directly antagonizes the biological activity of the canonical gene product

Longitudinal biomarkers in amyotrophic lateral sclerosis

OBJECTIVE: To investigate neurodegenerative and inflammatory biomarkers in people with amyotrophic lateral sclerosis (PALS), evaluate their predictive value for ALS progression rates, and assess their utility as pharmacodynamic biomarkers for monitoring treatment effects. METHODS: De-identified, longitudinal plasma, and cerebrospinal fluid (CSF) samples from PALS (n = 108; 85 with samples from \u3e /=2 visits) and controls without neurological disease (n = 41) were obtained from the Northeast ALS Consortium (NEALS) Biofluid Repository. Seventeen of 108 PALS had familial ALS, of whom 10 had C9orf72 mutations. Additional healthy control CSF samples (n = 35) were obtained from multiple sources. We stratified PALS into fast- and slow-progression subgroups using the ALS Functional Rating Scale-Revised change rate. We compared cytokines/chemokines and neurofilament (NF) levels between PALS and controls, among progression subgroups, and in those with C9orf72 mutations. RESULTS: We found significant elevations of cytokines, including MCP-1, IL-18, and neurofilaments (NFs), indicators of neurodegeneration, in PALS versus controls. Among PALS, these cytokines and NFs were significantly higher in fast-progression and C9orf72 mutation subgroups versus slow progressors. Analyte levels were generally stable over time, a key feature for monitoring treatment effects. We demonstrated that CSF/plasma neurofilament light chain (NFL) levels may predict disease progression, and stratification by NFL levels can enrich for more homogeneous patient groups. INTERPRETATION: Longitudinal stability of cytokines and NFs in PALS support their use for monitoring responses to immunomodulatory and neuroprotective treatments. NFs also have prognostic value for fast-progression patients and may be used to select similar patient subsets in clinical trials

PAM50 proliferation score as a predictor of weekly paclitaxel benefit in breast cancer

To identify a group of patients who might benefit from the addition of weekly paclitaxel to conventional anthracycline-containing chemotherapy as adjuvant therapy of node-positive operable breast cancer. The predictive value of PAM50 subtypes and the 11-gene proliferation score contained within the PAM50 assay were evaluated in 820 patients from the GEICAM/9906 randomized phase III trial comparing adjuvant FEC to FEC followed by weekly paclitaxel (FEC-P). Multivariable Cox regression analyses of the secondary endpoint of overall survival (OS) were performed to determine the significance of the interaction between treatment and the (1) PAM50 subtypes, (2) PAM50 proliferation score, and (3) clinical and pathological variables. Similar OS analyses were performed in 222 patients treated with weekly paclitaxel versus paclitaxel every 3 weeks in the CALGB/9342 and 9840 metastatic clinical trials. In GEICAM/9906, with a median follow up of 8.7 years, OS of the FEC-P arm was significantly superior compared to the FEC arm (unadjusted HR = 0.693, p = 0.013). A benefit from paclitaxel was only observed in the group of patients with a low PAM50 proliferation score (unadjusted HR = 0.23, p < 0.001; and interaction test, p = 0.006). No significant interactions between treatment and the PAM50 subtypes or the various clinical–pathological variables, including Ki-67 and histologic grade, were identified. Finally, similar OS results were obtained in the CALGB data set, although the interaction test did not reach statistical significance (p = 0.109). The PAM50 proliferation score identifies a subset of patients with a low proliferation status that may derive a larger benefit from weekly paclitaxel. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10549-013-2416-2) contains supplementary material, which is available to authorized users