Quantitative structured-illumination phase microscopy

We introduce a quantitative phase imaging method for homogeneous objects with a bright field transmission microscope by using an amplitude mask and a digital processing algorithm. A known amplitude pattern is imaged on the sample plane containing a thick phase object by placing an amplitude mask in the field diaphragm of the microscope. The phase object distorts the amplitude pattern according to its optical path length (OPL) profile, and the distorted pattern is recorded in a CCD detector. A digital processing algorithm then estimates the object's quantitative OPL profile based on a closed form analytical solution, which is derived using a ray optics model for objects with small OPL gradients.     

Optical encoder based on a nondiffractive beam

Optical encoders are used in industrial and laboratory motion equipment to measure rotations and linear displacements. We introduce a design of an optical encoder based on a nondiffractive beam. We expect that the invariant profile and radial symmetry of the nondiffractive beam provide the design with remarkable tolerance to mechanical perturbations. We experimentally demonstrate that the proposed design generates a suitable output sinusoidal signal with low harmonic distortion. Moreover, we present a numerical model of the system based on the angular spectrum approximation whose predictions are in excellent agreement with the experimental results.     

The role of tryptophan in protein fibrillogenesis: relevance of Trp7 and Trp14 to the amyloidogenic properties of myoglobin

In order to understand the role of tryptophan in the mechanisms of fibrils formation, the ability of a series of analogs of the residue 7-18 span of myoglobin to form amyloid-like fibrils was investigated. Alternatively one or both tryptophans were substituted with alanine and leucine, to determine the contribution of hydrophobicity and aromaticity. The scale of aggregation propensity of the peptides determined indicates that tryptophan is crucial for the amyloidogenic process. Since the rare tryptophan residue is generally engaged in structural roles in proteins, or when exposed serves as binding sites, we surmise that its exposure in the amyloidogenic fragments allows for intermolecular clustering with residues from other molecules leading to the formation of amyloid aggregates.     

Use of UV-C treatments to maintain quality and extend the shelf life of green fresh-cut bell pepper (Capsicum annuum L.)

Abstract: The objective of this work was to select a Ultraviolet‐C (UV‐C) treatment for fresh‐cut mature green bell pepper, and to evaluate the effect of its combination with refrigeration on quality maintenance. Bell pepper sticks were treated with 0, 3, 10, or 20 kJ/m² UV‐C in the outer (O), inner (I), or both sides of the pericarp (I/O) and stored for 8 d at 10 °C. During the first 5 d of storage, all UV‐C treatments reduced deterioration as compared to the control. The treatment with 20 kJ/m² I/O was the most effective to reduce deterioration, and was used for further evaluations. In a second group of experiments, mature green bell pepper sticks were treated with 20 kJ/m² I/O, stored at 5 °C for 7 or 12 d and assessed for physical and chemical analysis, and microbiological quality. UV‐C‐treated fruit showed lower exudates and shriveling than the control. UV exposure also reduced decay, tissue damage, and electrolyte leakage. After 12 d at 5 °C, UV‐C irradiated peppers remained firmer and had higher resistance to deformation than the control. The UV‐C treatments also reduced weight loss and pectin solubilization. UV‐C exposure decreased the counts of mesophile bacteria and molds, and did not affect acidity or sugars. UV‐C‐treated fruit stored for 0 or 7 d at 5 °C did not show major differences in antioxidants from the control as measured against DPPH^? or ABTS^?+ radicals. Results suggest that UV‐C exposure is useful to maintain quality of refrigerated fresh‐cut green pepper. Practical Application: Exposure to UV‐C radiation before packing and refrigeration could be a useful nonchemical alternative to maintain quality and reduce postharvest losses in the fresh‐cut industry.     

Spatially resolved characteristics of pharmaceutical sprays

Spatially resolved drop size, velocity, and volume flux data for five different spray coating guns were described in this study. Such spatially resolved measurements show how sprays respond to changes in operating conditions and gun design in ways that less complete measurements can not provide. Data for instance, allow us to recognize the unique drop size distribution of one of the sprays tested, which ultimately was an important factor in determining the dual roles of the shaping air flows: depending on drop size, viscosity, and the magnitude of the shaping air velocity, the shaping air can either pinch or induce secondary atomization to the sprays. When the former outweighs the latter, a dumbbell‐shaped spray develops; a more uniform spray results when the opposite occurs. Volume flux data from the different sprays also suggest that a more robust and consistent tablet coating process can likely be designed by utilizing multiple overlapping round sprays. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Children's low affective perspective-taking ability is associated with low self-initiated pro-sociality.

Children's affective perspective-taking (APT) may provide a basis for efficient social interaction. The APT abilities of 83 children from 46 same-sex sibling pairs (ages 36 to 72 months, M = 52.8; SD = 12.6) were assessed through their reactions to affectively loaded story situations, and children whose APT ability (but not general cognitive abilities) was low relative to other children of their age were designated as Low-APT children. These children were not less pro-social when specific social cues or requests for pro-social behavior were given by experimenters. However, low APT may hinder children's ability to infer the need for pro-social action from relatively subtle social cues. Although 46.9% of nonlow APT children behaved pro-socially in at least two of three opportunities they were given to perform a self-initiated pro-social behavior, none of the children who were low on APT did. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Genetic and environmental influences on girls' and boys' gender-typed and gender-neutral values.

In this first investigation of genetic and environmental influences on children's values, 271 German twin pairs (50.2% boys) reported their values at ages 7–11 years using the Portrait Values Questionnaire (Schwartz & Rubel, 2005). We distinguished between gender-neutral (conservation vs. openness to change) and gender-typed (self-transcendence vs. self-enhancement) values. Boys differed from girls in the importance given to gender-typed benevolence, achievement, and power values. Gender-neutral values showed moderate (.34) and gender-typed values showed higher (.49) heritability, with nonshared environment and error accounting for the remaining variance. For both sexes, substantial genetic effects accounted for the importance children gave to their respective gender-stereotypical end of the self-transcendence versus self-enhancement dimension. However, dramatic sex differences emerged in the gender-atypical end of the distribution. For girls, low self-transcendence (high gender-atypical values) showed a large (.76) group heritability. For boys, gender-atypical values (high self-transcendence) showed no heritability and a modest (.10) shared environment effect. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Nitrogen concentration and nitrate/ammonium ratio affect yield and change the oxalic acid concentration and fatty acid profile of purslane (Portulaca oleracea L.) grown in a soilless culture system

Purslane is an excellent source of omega‐3 fatty acids, amino acids and vitamins. The aim of this research was to study the effect of different nitrogen levels and NO₃⁻‐N/NH₄⁺‐N ratios in the nutrient solution on the yield and on the oxalic acid content and fatty acid profile in purslane grown in a soilless culture system. Two experiments were carried out to test different levels of nitrogen: (1) 8–12–16 mmol L⁻¹ and (2) 0–12–24–36 mmol L⁻¹. A third experiment was carried out maintaining the N level fixed (12 mmol L⁻¹) but varying the NO₃⁻‐N/NH₄⁺‐N ratio: 60:40, 40:60, 0:100. The results indicated that plants grew with increasing nitrogen level up to 36 mmol L⁻¹. Nitrogen supplied in both NO₃⁻ and NH₄⁺ forms produced bigger plants than N supplied in NH₄⁺ form only. Nitrogen did not significantly influence the polyunsaturated fatty acid content in the canopy. Significant trends were found for α‐linolenic acid (LNA; 18:3 n‐3) and linoleic acid (LA; 18:2 n‐6), indicating a favorable accumulation of omega‐3 fatty acids with increasing N; palmitic acid decreased by increasing N and by switching the NO₃⁻/NH₄⁺ ratio towards the NH₄⁺ level in the nutrient solution, but using 0:100 NO₃⁻/NH₄⁺, decreased plant quality. Increasing N lowered oxalic acid production and palmitic acid content, enhancing purslane nutritional quality. Keeping a high N level in the nutrient solution with a 40:60 NO₃⁻/NH₄⁺ ratio would give the best results in terms of yield, oxalic acid concentration and fatty acid profile. Copyright © 2006 Society of Chemical Industry