Нанотехнологии сока. Мини-обзор

In the past two decades, nano-science is widely used in different applications and the increased interest in the utilization of nanoparticles in food processing is clear. Such applications include processing, packaging, development of functional food, safety, foodborne pathogens detection, and shelf-life extension. In this article, the essential facts and the latest uses of nano-science in fruit and vegetable juices were described. The green synthesis of nanoparticles with antioxidant, antibacterial and antifungal characteristics is of great interest in food preservation. These nanoparticles such as metals, oxidized metals and its bioactivity in juice were reviewed. The current procedures to prepare nanojuice including nanofiltration and the most recent nanomilling were presented. Beside the preparation, special emphasis has also been given to the chemical as well as the biological (microbial and enzymatic) quality of the produced nanojuice. The role of nanotechnology in the development of the smart and the active food packaging systems for the improvement of food shelf- life and quality was also discussed. Since the physical and chemical characteristics of nanoparticles are completely different from those of macro-size. Therefore, special and urgent attention by responsible authorities should be given and effective policies should be applied for food products to ensure product quality, customer health and safety as well as the environmental protection.В последние два десятилетия нанонаука широко используется в различных областях и очевиден повышенный интерес к применению наночастиц при переработке пищевых продуктов. Такие области включают переработку, упаковку, разработку функциональных продуктов, безопасность, обнаружение пищевых патогенов и продление сроков хранения. В данной статье описаны важнейшие факты и современное применение нанонауки для фруктовых и овощных соков. Большой интерес вызывает зеленый синтез наночастиц с антиоксидантными, антибактериальными и противогрибковыми свойствами для увеличения сроков хранения пищевых продуктов. Сделан обзор наночастиц, таких как металлы, некоторых видов их оксидов и окислов, и их биологическая активность в соке. Приведены современные процедуры для производства нано-соков, включая нано-фильтрацию и самое современное нано-измельчение. Помимо производства, особый акцент в обзоре сделан на химических, а также биологических (микробиологических и ферментативных) качественных характеристиках произведенных нано-соков. Также обсуждена роль нано-технологии в развитии систем «разумной» и активной упаковки для увеличения сроков хранения и улучшения качества пищевых продуктов. Показано, что физические и химические характеристики наночастиц полностью отличаются от характеристик частиц макроразмера. Сделан вывод о том, что производителям пищевой продукции при использовании новых технологий должно уделяться особое внимание обеспечению ее качества для сохранения доверия потребителей. При этом контролирующими и регулирующими организациями должна проводится эффективная политика по обеспечению безопасности пищевой продукции, сохранности здоровья потребителей и защиты окружающей среды

New application of microbial l-glutaminase as a flavor enhancing agent in beef burgers

L‑glutaminase (L‑glutamine amidohydrolase EC3.5.1.2) is the key enzyme in enhancing the taste and aroma of oriental fermented foods by increasing their glutamic acid content and as a result imparting a palatable taste. Beef burgers were prepared using different levels of the partially purified L- glutaminase (2.0 to10.0 U/100 g) prepared from Aspergillus oryzae NRRL 32567. Beef burgers treated with 6.0 U/100g and the others treated with monosodium glutamate (5000 ppm) were chemically, sensory and microbiologically evaluated and compared to untreated control during frozen storage at –18 ºC for 3 months. Treatment with L‑glutaminase (6 U/100g) resulted in an increase of 443% in glutamic acid and a reduction of 63% in glutamine contents resulting in an enhanced preferable taste and odor of the prepared beef burgers. Burgers treated with 6.0 U/100g exhibited the best odor, texture, taste and overall quality scores when compared to the untreated control and samples treated with monosodium glutamate (5000 ppm). During the frozen storage of all samples, an expected slight, but significant (p≤0.05), increase in the total mesophilic bacterial count was evident and such increase was quite acceptable since numbers did not exceed the limit of 5.7x103 cfu/g. Similarly, the total psychrotrophs did not exceed 3.7x102 cfu/g

GPU-based ultra-fast direct aperture optimization for online adaptive radiation therapy

Online adaptive radiation therapy (ART) has great promise to significantly reduce normal tissue toxicity and/or improve tumor control through real-time treatment adaptations based on the current patient anatomy. However, the major technical obstacle for clinical realization of online ART, namely the inability to achieve real-time efficiency in treatment re-planning, has yet to be solved. To overcome this challenge, this paper presents our work on the implementation of an intensity modulated radiation therapy (IMRT) direct aperture optimization (DAO) algorithm on graphics processing unit (GPU) based on our previous work on CPU. We formulate the DAO problem as a large-scale convex programming problem, and use an exact method called column generation approach to deal with its extremely large dimensionality on GPU. Five 9-field prostate and five 5-field head-and-neck IMRT clinical cases with 5\times5 mm2 beamlet size and 2.5\times2.5\times2.5 mm3 voxel size were used to evaluate our algorithm on GPU. It takes only 0.7~2.5 seconds for our implementation to generate optimal treatment plans using 50 MLC apertures on an NVIDIA Tesla C1060 GPU card. Our work has therefore solved a major problem in developing ultra-fast (re-)planning technologies for online ART

A mathematical framework for contact detection between quadric and superquadric surfaces

The calculation of the minimum distance between surfaces plays an important role in computational mechanics, namely, in the study of constrained multibody systems where contact forces take part. In this paper, a general rigid contact detection methodology for non-conformal bodies, described by ellipsoidal and superellipsoidal surfaces, is presented. The mathematical framework relies on simple algebraic and differential geometry, vector calculus, and on the C2 continuous implicit representations of the surfaces. The proposed methodology establishes a set of collinear and orthogonal constraints between vectors defining the contacting surfaces that, allied with loci constraints, which are specific to the type of surface being used, formulate the contact problem. This set of non-linear equations is solved numerically with the Newton-Raphson method with Jacobian matrices calculated analytically. The method outputs the coordinates of the pair of points with common normal vector directions and, consequently, the minimum distance between both surfaces. Contrary to other contact detection methodologies, the proposed mathematical framework does not rely on polygonal-based geometries neither on complex non-linear optimization formulations. Furthermore, the methodology is extendable to other surfaces that are (strictly) convex, interact in a non-conformal fashion, present an implicit representation, and that are at least C2 continuous. Two distinct methods for calculating the tangent and binormal vectors to the implicit surfaces are introduced: (i) a method based on the Householder reflection matrix; and (ii) a method based on a square plate rotation mechanism. The first provides a base of three orthogonal vectors, in which one of them is collinear to the surface normal. For the latter, it is shown that, by means of an analogy to the referred mechanism, at least two non-collinear vectors to the normal vector can be determined. Complementarily, several mathematical and computational aspects, regarding the rigid contact detection methodology, are described. The proposed methodology is applied to several case tests involving the contact between different (super)ellipsoidal contact pairs. Numerical results show that the implemented methodology is highly efficient and accurate for ellipsoids and superellipsoids.Fundação para a Ciência e a Tecnologia (FCT

The Continuous Sample of Working Lives: improving its representativeness

This paper studies the representativeness of the Continuous Sample of Working Lives (CSWL), a set of anonymized microdata containing information on individuals from Spanish Social Security records. We examine several CSWL waves (2005-2013) and show that it is not representative for the population with a pension income. We then develop a methodology to draw a large dataset from the CSWL that is much more representative of the retired population in terms of pension type, gender and age. This procedure also makes it possible for users to choose between goodness of fit and subsample size. In order to illustrate the practical significance of our methodology, the paper also contains an application in which we generate a large subsample distribution from the 2010 CSWL. The results are striking: with a very small reduction in the size of the original CSWL, we significantly reduce errors in estimating pension expenditure for 2010, with a p value greater or equal to 0.999

A fast ℓ1-solver and its applications to robust face recognition

In this paper we apply a recently proposed Lagrange Dual Method (LDM) to design a new Sparse Representation-based Classification (LDM-SRC) algorithm for robust face recognition problem. The proposed approach improves the efficiency of the SRC algorithm significantly. The proposed algorithm has the following advantages: (1) it employs the LDM ℓ1-solver to find solution of theℓ1-norm minimization problem, which is much faster than other state-of-the-art ℓ1-solvers, e.g. ℓ1-magic and ℓ1−ℓs . (2) The LDM ℓ1-solver utilizes a new Lagrange-dual reformulation of the original ℓ1-norm minimization problem, not only reducing the problem size when the dimension of training image data is much less than the number of training samples, but also making the dual problem become smooth and convex. Therefore it converts the non-smooth ℓ1-norm minimization problem into a sequence of smooth optimization problems. (3) The LDM-SRC algorithm can maintain good recognition accuracy whilst reducing the computational time dramatically. Experimental results are presented on some benchmark face databases