A hybrid p-Si/poly(1,4-diaminoanthraquinone) photoconductive diode for optical sensor applications

We report on the fabrication and characterization of a hybrid Si/poly(1,4-diaminoanthraquinone) photoconductive diode for optical sensor applications. The electrical and photoconductivity properties of the diode have been investigated by dark current–voltage, steady-state and transient photoconductivity measurements. At lower voltages, the current mechanism of the diode is controlled by thermionic emission theory, whereas at higher voltages, the current mechanism is controlled by space charge limited current due to the electrical conductivity of the poly(1,4-diaminoanthraquinone). The ideality factor, barrier height and series resistance values of the diode were found to be 1.72, 0.82 eV and 1.15 MΩ, respectively. The steady-state photoconductivity mechanism of the diode indicates the presence of continuous distribution of trap levels. The transient photoconductivity results indicate that the photocurrent of the diode was varied from 1.81 × 10^?12 to 8.16 × 10^?7 A. This suggests that the photocurrent under the illumination of 3500 lx is 4.50 × 10⁵ times higher than the dark current. It is evaluated that the hybrid Si/poly(1,4-diaminoanthraquinone) device is a photoconductive diode with photovoltaic properties.     

Wiener-Hopf analysis of the two-dimensional box-like horn radiator

A hybrid method consisting of employing the mode-matching method in conjunction with the Fourier transform technique is used to analyze the radiation of the dominant TEM-wave from a two-dimensional rectangular horn. The hybrid method that we will adopt reduces the related boundary value problem into a scalar modified Wiener-Hopf equation of the third kind. The solution involves branch-cut integrals which are evaluated approximately and infinitely many unknown constants satisfying an infinite system of linear algebraic equations susceptible to a numerical treatment. Some computational results illustrating the effects of various parameters such as waveguide width, horn length, etc., on the radiation phenomenon are also presented. Comparison of the results with those obtained for a similar finite structure is proved satisfactory.     

Micromilling of microbarbs for medical implants

Successful application of many implantable medical devices often depends on the technique used for attaching the devices to living tissue. Although mechanical attachment techniques that use micro-scale piercing elements are very promising, the fabrication of the micro-scale piercing elements poses considerable challenges. In this paper, the use of the mechanical micromilling process for fabrication of micro-scale piercing elements (microbarbs) from biocompatible materials is investigated. Two micro-scale milling tools with custom geometries are used during the fabrication. To gain an understanding of the process conditions on the performance metrics of micromilling forces, surface roughness, and burr formation, a design of experiments study is performed on polymethyl methacrylate (PMMA). The geometric capability of the process is demonstrated by fabricating PMMA microbarbs with different sizes (widths from 68 to ), edge sharpnesses (60 and 90 included angles), and heights (from 84 to ). The capability to micromill a variety of biocompatible materials is demonstrated by creating microbarbs from non-biodegradable 304 stainless steel and PMMA, from bioresorbable polylactic acid (PLA), and from a fibrin based plastic. It is concluded that the micromilling process can be used for effectively fabricating arrays of microbarbs.     

Invitro digestion and absorption efficiency of homogenised milk lipids

The effects of homogenisation, heat treatment and their order on in vitro gastric/pancreatic digestions, and in vitro absorption of milk lipids, expressed as free fatty acids, were investigated. Milk, cream or mixture of homogenised/heat‐treated cream and skim milk were subjected to gastric digestion at pH 2 or 6, followed by pancreatic digestion and cell absorption by CaCo‐2 cells. Heat treatment after or prior to homogenisation affected in vitro digestion efficiencies of milk lipids. The presence of milk proteins led to reductions in the levels of gastric/pancreatic digestion of homogenised milk lipids. Absorption of FFA was not affected by gastric digestion pH.     

Production and characterization of bio-oil and biochar from rapeseed cake

New and renewable fuels are the major alternatives to conventional fossil fuels. Biomass in the form of agricultural residues is becoming popular among new renewable energy sources, especially given its wide potential and abundant usage. Pyrolysis is the most important process among the thermal conversion processes of biomass. In this study, the production of bio-oil and biochar from rapeseed cake obtained by cold extraction pressing was investigated and the various characteristics of biochar and bio-oil acquired under static atmospheric conditions were identified. The biochar obtained are carbon rich, with high heating value and relatively pollution-free potential solid biofuel. The bio-oil product was presented as an environmentally friendly green biofuel candidate.     

Functionalized micromachines for selective and rapid isolation of nucleic acid targets from complex samples

The transport properties of single-strand DNA probe-modified self-propelling micromachines are exploited for "on-the-fly" hybridization and selective single-step isolation of target nucleic acids from "raw" microliter biological samples (serum, urine, crude E. coli lysate, saliva). The rapid movement of the guided modified microrockets induces fluid convection, which enhances the hybridization efficiency, thus enabling the rapid and selective isolation of nucleic acid targets from untreated samples. The integration of these autonomous microrockets into a lab-on-chip device that provides both nucleic acid isolation and downstream analysis could thus be attractive for diverse applications.     

Diphenolases from two cultivars of cherry laurel (Laurocerasus officinalis Roem.) fruits at an early stage of maturation

Diphenolases from two cherry laurel cultivars (Laurocerasus officinalis Roem. ‘Globigemmis’ and ‘Oxygemmis’) were highly active against 3-(3,4-dihydroxyphenyl)propionic acid (DHPPA) at acidic pH values with temperature optima of 50 and 40 °C, respectively. Although the pH-stability profiles showed that both enzymes were fully stable at pH 7.0, their stabilities decreased significantly at alkaline pH values. Thermal-stabilities of the cherry laurel diphenolases indicated that enzymes from the two cultivars share similar thermodynamic properties and heat-sensitivities as a result of heat-inactivation. In addition, ascorbate and metabisulfite, at 1 mM final concentrations, almost completely inhibited the oxidation of DHPPA by the enzymes, indicating the sensitivities of the cherry laurel diphenolases from the two cultivars towards general Polyphenol oxidases inhibitors. It can be concluded that the crude enzymes prepared from the cherry laurel fruits of the two cultivars, at an early stage of development, possess diphenolase activities sharing similar behaviours.     

Effect of addition of amino acids, treatment with β-galactosidase and use of heat-shocked cultures on the acetaldehyde level in yoghurt

In this study, the biochemical activities of nonviscous and viscous yoghurt starter cultures were investigated. Yoghurt samples produced with nonviscous and viscous cultures, and viscous cultures + methionine (10 and 30 mg/100 mL milk), + threonine (5 and 10 mg/100 mL milk), + β-galactosidase (1 mg/100 mL milk), and with a heat-shocked culture were analysed. In the experimental yoghurts, the pH, titratable acidity, lactic acid, tyrosine and acetaldehyde contents and the number of total starter organisms were determined. According to the results obtained, the samples produced with the viscous culture had the lowest acetaldehyde levels, whereas the highest acetaldehyde level was found in the samples manufactured with the nonviscous culture. Compared with the samples inoculated with the viscous culture alone, the amino acid supplementation, lactose hydrolysis and heat-shock treatments caused a significant increase in the level of acetaldehyde.     

Influence of infrared final cooking on polycyclic aromatic hydrocarbon formation in ohmically pre-cooked beef meatballs

Effects of infrared cooking on polycyclic aromatic hydrocarbon (PAH) formation in ohmically pre-cooked beef meatballs were investigated. Samples were pre-cooked in a specially designed-continuous type ohmic cooking at a voltage gradient of 15.26 V/cm for 92 s. Infrared cooking was applied as a final cooking method at different combinations of heat fluxes (3.706, 5.678, 8.475 kW/m²), application distances (10.5, 13.5, 16.5 cm) and application durations (4, 8, 12 min). PAHs were analyzed by using high performance liquid chromatography (HPLC) equipped with a fluorescence detector. The total PAH levels were detected to be between 4.47 and 64 μg/kg. Benzo[a] pyrene (B[a]P) and PAH4 (sum of B[a]P, chrysene (Chr), benzo[a]anthracene (B[a]A) and benzo[b]fluoranthene (B[b]F)) levels detected in meatballs were below the EC limits. Ohmic pre-cooking followed by infrared cooking may be regarded as a safe cooking procedure of meatballs from a PAH contamination point of view.     

Effects of different lairage times after long distance transportation on carcass and meat quality characteristics of Hungarian Simmental bulls

The objective of this study was to determine the effects of three lairage times (24 h, 48 h and 72 h) on the meat quality of tame trained to lead Hungarian Simmental bulls subjected to long commercial transportation of approximately 1800 km. A total of 30 bulls, with an average age of 24 months, were used. During the lairage, bulls received 0.5 kg concentrate feed per animal per day and ad libitum access to the hay and water. As the lairage duration increased, the pH_ult decreased (P < 0.05). Bulls lairaged for 24 h had lower L*, b* and H* values than those lairaged for 48 h and 72 h (P < 0.05). The effect of lairage time on WHC, cooking loss and Warner–Bratzler shear force values was not significant. The b* value was considered the best predictor of muscle pH_ult. In conclusion, 72 h quiet lairage time is recommended after transportation in order to prevent the adverse effects of transportation on meat quality.