Preparation of dibasic acid-containing soy phospholipids by chemical and enzyme-catalyzed transesterification and evaluation of their surface-active properties

The preparation of dibasic acid-containing soy phospholipid was made by transesterification reaction with alkyl ester of diabasic acid with both lipase and alkoxide as a catalyst. The extent of incorporation of a dibasic acid varied with the molecular size of the dibasic acid. The extent of incorporation in soy phospholipids was 4–13% in the case of adipic acid and 9–20% in the case of sebacic acid. The surface-active properties of these modified soy phospholipids were examined and were found to be different from those of the original (unmodified) soy phospholipid. The interfacial properties such as critical micelle concentration (CMC), γ_CMC, surface excess concentration Γ_max, and minimum area per molecule (Å), and thermodynamic parameters such as standard free energy of micellization, were found to depend on the hydrophobic part of the dibasic acids.     

A Novel Contour Tracing Algorithm for Object Shape Reconstruction Using Parametric Curves

Parametric curves such as Bézier and B-splines, originally developed for the design of automobile bodies, are now also used in image processing and computer vision. For example, reconstructing an object shape in an image, including different translations, scales, and orientations, can be performed using these parametric curves. For this, Bézier and B-spline curves can be generated using a point set that belongs to the outer boundary of the object. The resulting object shape can be used in computer vision fields, such as searching and segmentation methods and training machine learning algorithms. The prerequisite for reconstructing the shape with parametric curves is to obtain sequentially the points in the point set. In this study, a novel algorithm has been developed that sequentially obtains the pixel locations constituting the outer boundary of the object. The proposed algorithm, unlike the methods in the literature, is implemented using a filter containing weights and an outer circle surrounding the object. In a binary format image, the starting point of the tracing is determined using the outer circle, and the next tracing movement and the pixel to be labeled as the boundary point is found by the filter weights. Then, control points that define the curve shape are selected by reducing the number of sequential points. Thus, the Bézier and B-spline curve equations describing the shape are obtained using these points. In addition, different translations, scales, and rotations of the object shape are easily provided by changing the positions of the control points. It has also been shown that the missing part of the object can be completed thanks to the parametric curves.     

Self-esteem development from young adulthood to old age: A cohort-sequential longitudinal study.

The authors examined the development of self-esteem from young adulthood to old age. Data came from the Americans’ Changing Lives study, which includes 4 assessments across a 16-year period of a nationally representative sample of 3,617 individuals aged 25 years to 104 years. Latent growth curve analyses indicated that self-esteem follows a quadratic trajectory across the adult life span, increasing during young and middle adulthood, reaching a peak at about age 60 years, and then declining in old age. No cohort differences in the self-esteem trajectory were found. Women had lower self-esteem than did men in young adulthood, but their trajectories converged in old age. Whites and Blacks had similar trajectories in young and middle adulthood, but the self-esteem of Blacks declined more sharply in old age than did the self-esteem of Whites. More educated individuals had higher self-esteem than did less educated individuals, but their trajectories were similar. Moreover, the results suggested that changes in socioeconomic status and physical health account for the decline in self-esteem that occurs in old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acrylamide formation and colour development in low-fat baked potato products as influenced by baking conditions and oil type

The objective of this study was to investigate the effect of oil type and oxidation status on acrylamide (AA) formation and colour development in potato products under domestic baking conditions. Sunflower, soybean and olive oil were used; the first one was thermally oxidized to obtain different oxidation status. A potato dough containing 10 % oil, potato powder, flour and water was shaped into thin discs and baked at 180 °C for different heating times. AA concentration, moisture content and surface colour were determined. Results obtained showed that neither the nature of lipids present, in terms of content of unsaturated fatty acids, nor the degree of fat oxidation influenced AA formation in low-fat baked potato products. Browning ratio higher than 45 % and moisture content lower than 17 % resulted in dark brown, almost burnt, products. Moreover, in those cases, no correlation could be found between those variables and AA content, since formation and degradation simultaneously occur. When the browning ratio ranged between 0 and 45 %, a good linear correlation with AA formation was observed, suggesting that the browning ratio may be considered as a reliable indicator of AA concentration. Finally, AA less than 1000 μg/kg, which is an indicative value that has been recently set for potato crisps by the European Commission, corresponds to a browning ratio of less than 8 % and moisture content more than 23.5 %.     

Measurement of the transient electrical and shaft torques in an induction motor drive by the indirect two-speed method

Contents This paper presents a new method, called Indirect Two-Speed Method (ITSM), for obtaining electrical and shaft torques in an induction motor drive by means of measuring the speeds of both lumped-inertia elements assigned to a second order model. The measuring is realized by using high-resolution digital tachometers (represented by incremental encoders), two frequency measurement systems based on the Double-Buffered Method, digitalfiltering of the raw speed data and numerical differentiation of the filtered speed data.

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Messung transienter Drehmomente eines Induktionsmotor-Antriebs mittels der Indirekten Zwei-Drehzahlen-Methode

Übersicht Im Beitrag wird ein neues Verfahren zur Ermittlung des elektrischen Moments und des Wellen-Drehmoments eines Induktionsmotor-Antriebs vorgestellt. Das als Indirekte Zwei-Drehzahlen-Methode (ITSM) bezeichnete Verfahren geht aus von einem mechanischen Modell zweiter Ordnung und mißt die Drehzahlen beider als konzentrierte Parameter betrachteten Drehmassen. Für die Durchführung werden hochauflösende digitale Tachometer eingesetzt. Die Frequenzmessung erfolgt durch ein Verfahren mit doppelter Pufferung, und es werden die Rohdaten nach digitaler Filterung numerisch differenziert.

     

Is hepcidin‐25 a predictor of atherosclerosis in hemodialysis patients?

Atherosclerotic cardiovascular disease is an important cause of mortality and morbidity in hemodialysis patients. Iron accumulation in arterial wall macrophages is increased in atherosclerotic lesions. Hepcidin is a key hepatic hormone regulating iron balance. It inhibits iron release from macrophages and iron absorption from enterocytes by binding and inactivating the cellular iron exporter ferroportin. The aim of this study is to investigate the relation of hepcidin‐25, iron parameters, and atherosclerosis measured by carotid intima media thickness (CIMT) in hemodialysis patients. Eighty‐two hemodialysis patients were enrolled in this cross‐sectional study. Predialysis blood samples were centrifuged at 1500 g and 4°C for 10 minutes and stored at ?80°C for the measurement of hepcidin‐25. DRG hepcidin enzyme‐linked immunosorbent assay kit was used for the measurement of hepcidin‐25. Ultrasonographical B‐mode imaging of bilateral carotid arteries was performed with a high‐resolution real‐time ultrasonography (Mindray DC7). Mean age of the study population was 57.90 ± 16.08 years and 43.9% were men. Total study population was grouped into two according to median value of hepcidin‐25. There was no difference between groups with respect to age, dialysis vintage, and C‐reactive protein. CIMT was found to be statistically significantly higher in low hepcidin‐25 group. In correlation analysis, CIMT was found to be correlated with age (P < 0.01, R = 0.33) and hepcidin‐25 (P < 0.01, R = 0.46). In linear regression analysis, age (β = 0.31) and hepcidin‐25 (β = 0.44) were found to be the determinants of CIMT in hemodialysis patients. Our results implicate that hepcidin may take part in pathophysiology of atherosclerosis and cardiovascular disease in hemodialysis patients.     

Heterologous Expression and Partial Characterization of a Putative Opine Dehydrogenase from a Metagenomic Sequence of Desulfohalobium retbaense

The aim of this research was to prove the function of the putative opine dehydrogenase from Desulfohalobium retbaense and to characterize the enzyme in terms of functional and kinetic parameters. A putative opine dehydrogenase was identified from a metagenomic library by a sequence-based technique search of the metagenomic library, and afterward was successfully heterologously produced in Escherichia coli. In order to examine its potential for applications in the synthesis of secondary amines, first the substrate specificity of the enzyme towards different amino donors and amino acceptors was determined. The highest affinity was observed towards small amino acids, preferentially L-alanine, and when it comes to α-keto acids, pyruvate proved to be a preferential amino acceptor. The highest activity was observed at pH 6.5 in the absence of salts. The enzyme showed remarkable stability in a wide range of experimental conditions, such as broad pH stability (from 6.0–11.0 after 30 min incubation in buffers at a certain pH), stability in the presence of NaCl up to 3.0 M for 24 h, it retained 80 % of the initial activity after 1 h incubation at 45 °C, and 65 % of the initial activity after 24 h incubation in 30 % dimethyl sulfoxide.     

On the determination of characteristic temperatures in power oil transformers during transient states

Contents Under usual assumptions the equations describing thermal phenomena in a transformer are established. Without neglecting any substantially important factor, algorithms are developed for predicting the temperatures in critical spots in non-stationary states occurring either in practice or in load/time diagrams. This paper suggests the determinaton of conductances dependent on temperature and constant capacitances of equivalent thermal circuits of a transformer. They are based on a small number of experiments (as simple as possible) and on a parameter estimation procedure. In such a way the temperatures of transformer parts in different transient states can be determined by computer simulation established on equivalent circuits, so the operators in power and sub-stations will be able to load their transformers close to the permitted limit. It is felt that this paper may give a stimulation for a possible revision of IEC rules.

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Ermittlung charakteristischer Temperaturen von Leistungs-Öl-Transformatoren im nichtstationären Betrich

Übersicht Die Gleichungen des Temperaturverhaltens eines Transformators werden unter den üblichen Annahmen aufgestellt. Es werden Algorithmen entwickelt, welche die Vorausbestimmung der Temperatur an kritischen Stellen bei nichtstationärem Betrieb erlauben. Vorgeschlagen wird die Bestimmung der temperaturabhängigen und-unabhängigen Parameter auf Grund von wenigen und einfachen Messungen. Damit kann das Personal in Verteilerstationen in die Lage versetzt werden, mit Hilfe von PC's die Belastung der Transformatoren bis zu den zulässigen Grenztemperaturen auszudehnen. Die Autoren möchten damit einen Anstoß zu einer möglichen Überarbeitung von IEC-Vorschriften geben.