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In this paper, we systematically address the performance of cellulose nanocrystals (CNs) coated flexible food packaging films. Firstly, the morphology of CNs from cotton linters and homogeneity of its coating on different substrates were characterized by transmission electronic microscopy and atomic force microscopy. Then, the 1.5 μm thick CNs coating on polyethylene terephthalate (PET), oriented polypropylene, oriented polyamide (OPA), and cellophane films were characterized for their mechanical, optical, anti-fog, and barrier properties. CNs coating reduces the coefficient of friction while maintaining high transparency (~90 %) and low haze (3-4 %) values, and shows excellent anti-fog properties and remarkable oxygen barrier (oxygen permeability coefficient of CNs coating, P'O, 0.003 cm μm m 24 h kPa). In addition, the Gelbo flex test combined with oxygen permeance (PO) measurements and optical microscopy are firstly reported for evaluating the durability of coatings, revealing that the CNs coated PET and OPA provide the best performance among the investigated coated films. CNs are therefore considered to be a promising multi-functional coating for flexible food packaging. [ABSTRACT FROM AUTHOR]

Abstract: We address the oxygen-barrier properties of a nanocomposite created by layer-by-layer assembly of two biopolymers, chitosan (CS) and cellulose, in nanocrystals form (CNs), on an amorphous PET substrate. We systematically investigated the oxygen permeability, morphology, and thickness of the nanocomposite grown under two different pH combinations and with different number of deposition cycles, up to 30 bilayers. Noticeably, the thickness of each deposited bilayer can be largely tuned by the pH value of the solution, from ∼7 up to ∼26nm in the tested conditions. By our analysis, it is reliably concluded that such CS/CNs nanocomposite holds promises for gas barrier applications in food and drug packaging as a clear coating on plastic films and tridimensional objects, improving performance and sustainability of the final packages. [Copyright &y& Elsevier]

Two-pulse correlation is employed to investigate thetemporal dynamicsof both two-photon photoluminescence (2PPL) and four-photon photoluminescence(4PPL) in resonant and nonresonant nanoantennas excited at a wavelengthof 800 nm. Both 2PPL and 4PPL data are consistent with the same two-stepmodel already established for 2PPL, implying that the first excitationstep in 4PPL is a three-photon sp → sp direct interband transition.Considering energy and parity conservation, we also explain why 4PPLbehavior is favored over, for example, three- and five-photon photoluminescencein the power range below the damage threshold of our antennas. Sincesizable 4PPL requires larger peak intensities of the local field,we are able to select either 2PPL or 4PPL in the same gold nanoantennasby choosing a suitable laser pulse duration. We thus provide a firstconsistent model for the understanding of multiphoton photoluminescencegeneration in gold nanoantennas, opening new perspectives for applicationsranging from the characterization of plasmonic resonances to biomedicalimaging. [ABSTRACT FROM AUTHOR]

Background and Objective: In patients with advanced cancer, cachexia correlates with low performance status and poor quality of life. In addition, cachexia may be associated with reduced response to chemoradiotherapy and a poor prognosis in cancer patients. Nearly all forms of cachexia are closely associated with chronic inflammation and elevated levels of inflammatory and pro-inflammatory circulating factors, including C-reactive protein (CRP), which is considered a valid laboratory and clinical marker. Among the different pathways involved in the production of inflammatory cytokines and chemokines, the vitamin D- vitamin D receptor (VDR) axis plays a fundamental role. In this study, we explore the possible association between CRP and key factors pertaining to the vitamin D axis - in particular, VDR gene polymorphisms - in cancer patients with cachexia. Although certain tumor types are more commonly associated with cachexia, even within the same tumor type there are significant differences in the extent and duration of cachexia. Such variations may be due to polymorphisms of the VDR gene that could lead to cachexia-prone genotypes or to cachexia-resistant genotypes. Identification of such genotypes could be very helpful in the management of cancer patients. Methods: Forty-three cancer patients were recruited by the Nutritional Unit of the Prato Hospital. Data on age, gender, type of cancer, stage of cancer, and nutritional assessment, as well as transferrin, ferritin, albumin, and CRP levels, were collected. Genomic DNA was extracted from peripheral blood leukocytes and amplified by polymerase chain reaction. BsmI, ApaI, TaqI, and FokI polymorphisms of the VDR gene were investigated using the respective restriction enzymes. For the different VDR polymorphisms, the absence or presence of the restriction sites were designated with capital or small letters, respectively. For example, for the BsmI polymorphism, the presence of the undigested fragment identified the B allele, whereas the presence of the digested fragment identified the b allele. Results: Cancer patients with cachexia have higher CRP levels compared with non-cachectic cancer patients, independently from the genotype. In cachectic patients, the presence of specific VDR BsmI and TaqI alleles was associated with higherCRPlevels. In particular, theVDRb and T alleles were more frequent in cachectic cancer patients with elevated CRP levels than in cachectic patients with normal CRP levels. Conclusion: From these results, we hypothesize that there is an association between BsmI and TaqI VDR gene polymorphisms and the cachectic syndrome. In particular, we propose that in cancer patients, the concomitance of b and T alleles with elevated CRP levels may represent an early clinical predictor for the development of a more aggressive form of cachexia. [ABSTRACT FROM AUTHOR]

Modeling optical tweezers in the T-matrix formalism has been of key importance for accurate and efficient calculations of optical forces and their comparison with experiments. Here we extend this formalism to the modeling of chiral optomechanics and optical tweezers where chiral light is used for optical manipulation and trapping of optically active particles. We first use the Bohren decomposition to deal with the light scattering of chiral light on optically active particles. Thus, we show analytically that all the observables (cross sections, asymmetry parameters) are split into a helicity dependent and independent part and study a practical example of a complex resin particle with inner copper-coated stainless steel helices. Then, we apply this chiral T-matrix framework to optical tweezers where a tightly focused chiral field is used to trap an optically active spherical particle, calculate the chiral behaviour of optical trapping stiffnesses and their size scaling, and extend calculations to chiral nanowires and clusters of astrophysical interest. Such general light scattering framework opens perspectives for modeling optical forces on biological materials where optically active amino acids and carbohydrates are present. [ABSTRACT FROM AUTHOR]

The chemical vapor deposition of silicon on a patterned silicon substrate leads to the formation of 3D microcrystals, which, due to their inclined top facets and high aspect ratio, produce a light‐trapping effect enhancing the optical absorption in the near‐infrared (NIR). In this work, it is demonstrated that Si microcrystals can form the building blocks of a new class of NIR sensitive photodetectors operating in a linear or avalanche regime. Microcrystal‐based devices are designed by coupling a 2D kinetic‐growth model with a Poisson drift‐diffusion solver and fabricated by combining electron beam lithography and low‐energy plasma‐enhanced chemical vapor deposition (LEPECVD). The optoelectronic properties of microcrystal‐based p–i–n photodiodes are investigated both theoretically and experimentally by means of finite‐difference time‐domain (FDTD) simulations and responsivity measurements. At 1000 nm wavelength, the responsivity of microcrystal‐based devices is six times higher than that of an equivalent mesa diode. Moreover, the photocurrent gains of Si microcrystals operating as an avalanche photodiode (APD), at the same wavelength, reaches 2 × 104 demonstrating the potentialities of substrate patterning, combined with epitaxial growth, for amplified photodetection applications. [ABSTRACT FROM AUTHOR]

We report on the experimental investigation, by means of spatially-resolved cathodoluminescence spectroscopy, of rectangular all-dielectric Ge nanoantennas sustaining Fabry-Perot resonances. The combination of spatial and spectral resolution allows us to directly image the standing-wave pattern of the local density of optical states inside the nanoantennas, which is the fingerprint of the resonant Purcell contribution to the overall emission enhancement previously reported in the literature for the same structures. Our results confirm that the emission properties of Ge nanostructures can be effectively tuned by engineering the local density of optical states and that cathodoluminescence provides valuable information to experimentally address such modulation in their emission properties. [ABSTRACT FROM AUTHOR]