Technical Properties of Regenerated Plastic Material Bars Produced from Recycled Agricultural Plastic Film

The increased use of plastic material in many different agricultural applications causes high volumes of waste. The mechanical recycling of postconsumption plastic is a suitable system for the recovery of these materials. With the aim of evaluating the mechanical and physical characteristics of plastic bars’ profiles, obtained by recycling different polymeric mixtures of agricultural plastic film. Experimental tests were performed on different blends of heterogeneous material. Bars, made from recycled agricultural plastic film were produced through mechanical recycling, mixed with calcium carbonate, high density polyethylene, ‘densified’ polyethylene from scrap material, wood powder, and glass fibers.     

Edge-defined metric buckling of temperature-responsive hydrogel ribbons and rings

We report the temperature-responsive buckling of ribbon-like hydrogel thin films based on photo-crosslinkable copolymers of poly(N-isopropyl acrylamide) (PNIPAM) with pendent benzophenone units. Due to the finite resolution of the photo-lithographic patterning method—here dominated by the convergence of light from the illumination source—nominally homogeneous layers are always surrounded by a more highly swelling border with a lateral size scale similar to the film thickness. As one of the in-plane dimensions of the gel sheet is reduced to only several times its thickness, this edge effect serves as a sufficiently large imperfection to drive buckling of the otherwise metrically flat ribbon. Due to the symmetric geometry, the resulting geometry has essentially constant curvature of the mid-line of the ribbon, with a radius of curvature defined by its thickness and width. In this manner, we prepare thermally responsive overcurved rings that buckle into more highly coiled configurations as they swell, due to the mismatch in metric curvature relative to the geometric shape of the object. We consider the conditions for unfrustrated coiling of both circular and polygonal rings in terms of the number of self-crossings made upon wrapping the surface of a sphere, and demonstrate the fabrication of ‘self-cinching unknots’, i.e. coiled ribbons that can fasten themselves onto other objects upon deswelling, due to topological constraints.     

Internal multiple-scattering hole-enhanced Raman spectroscopy: improved backscattering Fourier transform Raman sampling in pharmaceutical tablets utilizing cylindrical-conical holes

The benefits of Raman signal enhancement and improved measurement precision are demonstrated using 180° backscattering Fourier transform Raman (FT-Raman) spectroscopy from drilled cylindrical-conical holes within pharmaceutical tablet cores. Multiple scattering of the incident laser light within the holes results in an increased Raman signal due to the larger Raman sampling volume. This is important for overcoming typical sub-sampling issues encountered when employing FT-Raman backscattering of heterogeneous pharmaceutical tablets. Hole depth and diameter were found to be important experimental parameters and were optimized to yield the greatest signal enhancement. The FT-Raman spectra collected using backscattering from cylindrical-conical holes is compared to typical 180° backscattering from flat surfaces using tablet cores of Excedrin? and Vivarin?. Raman chemical images are used to establish a representative sampling area. We observe a three- to five-fold increase in the Raman intensity and a two-fold improvement in the measurement precision when sampling from cylindrical-conical holes rather than classic backscattering from flat tablet cores. Self-absorption effects on analyte band ratios are negligible in the fingerprint region but are more significant at the higher near-infrared (NIR) absorbances found in the C-H/O-H/-N-H stretching region. The sampling technique will facilitate developing quantitative FT-Raman methods for application to pharmaceutical tablets using the fingerprint spectral region.     

Study of green Sicilian table olive fermentations through microbiological,chemical and sensory analyses

The production of five different green table olive cultivars was studied by a combined strategy consisting of chemical, microbiological and sensory analyses. Cultivable microflora of samples collected during processing was monitored by plate counts on seven synthetic culture media. In all samples Enterobacteriaceae, Pseudomonaceae, staphylococci, lactic acid bacteria and spore-forming bacteria were undetectable. Yeasts and moulds were countable from the day 42 (2 log CFU/ml) till the end of fermentation (6 log CFU/ml). The use of three different approaches for microorganism detection, including a culture-independent methodology, revealed the presence of barely three yeast species during the entire fermentation period: Candida parapsilosis, Pichia guilliermondii and Pichia kluyveri. Biochemical features of technological interest were evaluated for 94 strains in order to investigate their potential role in fermentation of green Sicilian table olives.     

Homoepitaxial CVD diamond: Raman and time-resolved PL characterization

In this work, we report on the structural characterization of homoepitaxial Microwave Plasma Enhanced CVD diamond grown onto Ib diamond substrates by varying systematically the methane to hydrogen ratio in the gas mixture (1–7% CH₄). X-ray diffraction, Raman spectroscopy and photoluminescence (PL) have been used to characterize the diamond samples. Raman measurements pointed out the excellent crystalline quality and phase purity of the specimens. PL measurements in the 1.7–2.7 eV energy range have shown completely flat spectra, excluding the presence of nitrogen-related optical centers. Such results show that the homoepitaxial CVD diamond can be grown, at moderate microwave power (720 W), and at growth rates not too low ( 1 μm/h) preserving a good quality. Moreover, the homoepitaxial crystals exhibited a strong free-exciton recombination radiation at room temperature even at the highest methane concentration used (7%). Preliminary measurements of the lifetime of the free exciton at room temperature have been also performed. The excitation was produced by a 5 ns pulsed laser irradiation at energies above the diamond band gap. The results have been compared with the structural properties of the samples and correlated with the growth conditions.     

A twin study of smoking, nicotine dependence, and major depression in men.

This study examined the nature of the relationship among lifetime major depression, smoking, and nicotine dependence. Subjects were 8,169 male twins from the Vietnam Era Twin Registry. Biometrical modeling demonstrated a genetic influence on daily smoking, nicotine dependence, and major depression, and a family environmental influence on daily smoking. Genetic factors influencing nicotine dependence also strongly influenced major depression. We also compared probands with a history of major depression (n = 398) from pairs discordant for major depression, their nondepressed cotwins (n = 364), and controls (n = 1,863) on a number of secondary smoking outcomes. Major depression was associated with current daily smoking and certain nicotine withdrawal symptoms. Individuals with a familial vulnerability for major depression, even without a personal history of major depression, were more likely to smoke despite a serious illness and to report nervousness, restlessness, difficulty concentrating, and depressed mood during past quit attempts. Among the 237 monozygotic pairs discordant for major depression, depressed probands were more likely to have a lifetime history of nicotine dependence than were cotwins. Findings extend Kendler and colleague's (1993) study of female twins by demonstrating in men that shared genetic factors predispose not only to major depression and daily smoking but also to major depression and nicotine dependence.     

Assessment of quality‐assured Tarocco orange fruit sorting rules by combined physicochemical and sensory testing

BACKGROUND: The aim of this study was to extract a sorting rule for Tarocco orange fruit from several physicochemical and sensory tests performed on a marketable lot of 399 Tarocco orange fruits. RESULTS: The elastic tension at 5% strain (T₅) was found to be linearly correlated (r = 0.65) with the Magness–Taylor (MT) index. Thus T₅ was regarded as a non‐destructive parameter quantifying fruit firmness and used to categorise the aforementioned lot in three different firmness classes, high (HF), medium (MF) and low (LF). Only the MT index, fruit rind thickness near the fruit peduncle, lightness coefficient and yellow/blue hue component of the orange flesh, as well as total soluble solid content, confirmed the validity of this discrimination at the significance level of 5%. Sensory professionals recognised the greater compactness (7 ± 2) but lower ease of peeling (4 ± 2) and segment separation (4 ± 2) of the HF oranges with respect to the corresponding sensory attributes of orange fruits grouped in the MF and LF classes. CONCLUSION: To limit the costly rejection of Tarocco orange fruit considered too soft, especially after long‐term shipping, it would be reasonable to select only fruits characterised by a compressive force or tension at 5% strain in the range 23–41 N or 300–540 N m^?1 respectively. © 2012 Society of Chemical Industry     

Demonstration of droplet size and vaporization rate measurements in the near field of a two-phase jet with droplet lasing spectroscopy

Droplet lasing spectroscopy has been applied to the measurement of droplet size and evaporation rate in a spray. A single droplet, doped with laser dye, was injected along the centerline of a liquid spray. Filters were used to block the strong elastic-scattering signal. The lasing emission from the doped droplet could be detected against the background with mass loadings of liquid in the spray as high as 20%. An analysis of the spectrum of droplet lasing was used to evaluate the droplet diameter. The evaporation rate of the droplet was obtained from consecutive lasing spectra that were obtained from the same droplet. An error analysis of the drop size and drop evaporation measurements was carried out and showed that accurate measurements of evaporation rates were feasible.     

Arginase 2 and Polyamines in Human Pancreatic Beta Cells: Possible Role in the Pathogenesis of Type 2 Diabetes

Arginase 2 (ARG2) is a manganese metalloenzyme involved in several tissue specific processes, from physiology to pathophysiology. It is variably expressed in extra-hepatic tissues and is located in the mitochondria. In human pancreatic beta cells, ARG2 is downregulated in type 2 diabetes. The enzyme regulates the synthesis of polyamines, that are involved in pancreas development and regulation of beta cell function. Here, we discuss several features of ARG2 and polyamines, which can be relevant to the pathophysiology of type 2 diabetes.