Online comprehensive RPLC × RPLC with mass spectrometry detection for the analysis of proteome samples

LC-MS-based shotgun proteomics relies both on the power of the separation techniques and the sensitivity of detection methods. As a viable alternative to classical approaches in this field, we developed a fully automated, comprehensive 2D LC system, in which RPLC × RPLC was coupled to MS detection, for the first time, and applied for the analysis of tryptic digests obtained from α-casein and dephosphorylated α-casein. The use of a significantly different pH in the two dimensions allowed us to attain high peak capacity, despite the employment of novel identical stationary phases. Furthermore, such a combination addresses compatibility issues, thus allowing straightforward interfacing in online 2D LC configuration, as well as direct linkage to a mass spectrometer. A theoretical peak capacity of ca. 8500 was calculated for the setup, employing four serially coupled C18 columns in the first dimension (600 × 2.1 mm, 2.7 μm d.p.), operated under basic conditions, and 3 cm length of the same stationary phase (30 × 4.6 mm, 2.7 μm d.p. column), under acidic conditions, for fast second dimension analysis.     

In vitro hypoglycaemic and hypolipidemic potential of white tea polyphenols

The leaves at different processing stages of a single tea cultivar in order to obtain white (WT), green (GT) and black tea (BT) samples, were analysed. The capacities of tea polyphenolics to influence the glucose and lipid metabolism in HepG2 cell lines were evaluated. WT appeared the most active in reducing the glucose and cholesterol uptake (+17.7% and +32.4% in the glucose and cholesterol cell medium concentration, respectively). Incubation with WT enhanced LDL receptor binding activity by 40% (+20% for GT and +0% for BT) and led to an increase in HDL cell medium concentration of 33.3% (+20% for GT and +0% for BT). Finally, WT revealed the best inhibition capacity against lipase activity, and triglyceride levels in the cell medium increased by 400% (+382.6% for GT and +191.3% for BT). The present study intended to contribute to the little knowledge about the potential health benefits of white tea in individuals affected by metabolic syndrome.     

Power of interconnections and of nondeterminism in regularY-tree systolic automata

The increase of computational power due to additions of some horizontal interconnections between neighboring nodes of binary trees is investigated using the concept of systolic automata over so-called 7-trees with one-directional, bottom-to-root, flow of computation.Y-trees are obtained from binary trees by connecting some neighboring pairs of nodes at the same level that are not brothers.We introduce the concept of systolic automata on regularY-trees in column normal form and prove that any systolic automaton on regularY-trees is equivalent to one in the column normal form. We then fully characterize those regularY-trees over which the class of languages recognized by nondeterministic automata is the same as for deterministic automata. An analogous result is obtained for stability. Furthermore, we show that superstable deterministic systolic automata over regularY-trees recognize only regular languages. Finally, several closure properties of and relations between classes of languages accepted by systolic automata over differentY-trees are studied.The preliminary version of this paper was presented at the 2nd International Colloquium on Words, Languages, and Combinatorics in Kyoto, Japan, August 1992. This work has been partially supported by the Ministero dell' Universitá e della Ricerca Scientifica e Tecnologica of Italy and by a grant from the Slovak Academy of Sciences, Bratislava, Slovakia. The second author is on a leave of absence from the Institute of Informatics, Slovak Academy of Sciences, Bratislava, Slovakia.     

Compact permanent-magnet generator for hybrid vehicle applications

In hybrid electric vehicle (HEV) drivetrains an electrical generator is coupled onto the shaft of an internal-combustion engine (ICE) in order to process either the entire or a given fraction of the traction power required by the vehicle wheels. As such an ICE-driven generator is being confined within the vehicle hood and is exposed to heating resulting from ICE operation, high compactness, totally enclosed construction, and suitable machine cooling arrangement become challenging targets the generator design must deal with. Due to unique characteristics such as higher torque per volume and higher efficiency compared to other machine topologies, the axial-field permanent-magnet machine topology was selected for a 15-kW-at-4500-r/min-rated generator prototype that would be utilized in a demonstrator of an HEV drive train. This paper describes the original solutions adopted for the design of such an HEV generator and reports experimental results taken from the prototype machine.     

Mixed IgM kappa-IgM lambda cryoglobulinemia with a double monoclonal serum component. A case report

The regulation of breathing is dependent on the complex interaction of three components of the respiratory system: 1) the control centers, 2) the sensors, and 3) the effector organs. The control centers reside in the brainstem and are responsible for the automaticity of breathing. Input into these respiratory centers can be initiated from higher brain centers in order to produce voluntary breathing efforts. Afferent neural signals also come to the central control system from the respiratory sensors, which are divided into two categories: chemoreceptors and sensory receptors. The chemoreceptors respond to changes in the blood oxygen, carbon dioxide, and hydrogen ion concentration by sending impulses to the control center to alter the ventilatory pattern by affecting the effector organs--the respiratory muscles. The sensory receptors are located in the upper and lower airways, the lung, and the muscles of respiration. They also can have a marked effect on the respiratory pattern. It is believed that stimulation of these receptors is important in the initiation of hyperventilation and cough in lung diseases such as asthma. There is also recent evidence that respiratory chemoreceptor responsiveness is abnormal in patients with asthma who have a history of near-fatal attacks.     

Network constraint impacts on the competitive electricity markets under supply-side strategic bidding

In a competitive electricity market, the oligopoly structure of the market and the network constraints may produce results far from the perfect competition. This paper presents a comprehensive approach to evaluate the performances of the electricity markets with network representation in presence of bidding behavior of the producers in a pool system. A supply function strategic bidding model for the producers is introduced, and then different scenarios in terms of bidding behavior and network constraints are studied and compared on the basis of a set of microeconomic metrics. The aim of the paper is to assess, throughout a set of proper indices, the level of competition in a network-constrained market considering strategic behavior of the producers. The approach proposed gives the possibility to assess the different weight of strategic behavior of the producers and of the network constraints in distorting the market performances from its perfect competition equilibrium. From such an analysis, the worsening of the market efficiency and performances, due to the joint effects of the nonperfect competition and the network constraints, may be assessed and quantified, providing information on the adequacy of the grid considered for accommodating a competitive market. The exploitation of the proposed metrics for the market analysis is shown with reference to the IEEE 30-bus test system with demand elasticity explicitly represented.     

Immunohistochemical determination of nuclear antigens by colour image analysis: application for labelling index, estrogen and progesterone receptor status in breast cancer

The immunohistochemical evaluation of 5-bromo-2'-deoxyuridine (BrdU) labelling index, estrogen (ER) and progesterone receptor (PR) status was carried out on the automated computer-assisted image analysis station BIOCOM 500. Special software has been developed to measure nuclear antigens using the immunoperoxidase method with the Harris hematoxylin counterstain. The analysis was based on the different light adsorption spectra of the chromogen diaminobenzidine and Harris's hematoxylin coloration when exposed to light of differing wavelengths. The results obtained by image analysis were compared to previously validated methods. The thymidine labelling index performed by manual procedures and BrdU incorporation performed by image analysis were comparable (linear correlation coefficient r = 0.76, P < 0.001). Comparison of image analysis and dextran coated charcoal assay for ER and PR content revealed excellent sensitivities and specificities (linear correlation coefficient r = 0.87, P < 0.001 for ER and r = 0.93, P < 0.001 for PR). These data suggest that automated image analysis offers a reliable and reproducible procedure for measuring nuclear antigens.     

Glucose ingestion causes GLUT4 translocation in human skeletal muscle

In humans, ingestion of carbohydrates causes an increase in blood glucose concentration, pancreatic insulin release, and increased glucose disposal into skeletal muscle. The underlying molecular mechanism for the increase in glucose disposal in human skeletal muscle after carbohydrate ingestion is not known. We determined whether glucose ingestion increases glucose uptake in human skeletal muscle by increasing the number of glucose transporter proteins at the cell surface and/or by increasing the activity of the glucose transporter proteins in the plasma membrane. Under local anesthesia, approximately 1 g of vastus lateralis muscle was obtained from six healthy subjects before and 60 min after ingestion of a 75-g glucose load. Plasma membranes were isolated from the skeletal muscle and used to measure GLUT4 and GLUT1 content and glucose transport in plasma membrane vesicles. Glucose ingestion increased the plasma membrane content of GLUT4 per gram muscle (3,524 +/- 729 vs. 4,473 +/- 952 arbitrary units for basal and 60 min, respectively; P < 0.005). Transporter-mediated glucose transport into plasma membrane vesicles was also significantly increased (130 +/- 11 vs. 224 +/- 38 pmol.mg-1.s-1; P < 0.017), whereas the calculated ratio of glucose transport to GLUT4, an indication of transporter functional activity, was not significantly increased 60 min after glucose ingestion (2.3 +/- 0.4 vs. 3.0 +/- 0.5 pmol.GLUT4 arbitrary units-1.s-1; P < 0.17). These results demonstrate that oral ingestion of glucose increases the rate of glucose transport across the plasma membrane and causes GLUT4 translocation in human skeletal muscle. These findings suggest that under physiological conditions the translocation of GLUT4 is an important mechanism for the stimulation of glucose uptake in human skeletal muscle.     

Monitoring food quality by microfluidic electrophoresis, gas chromatography, and mass spectrometry techniques: effects of aquaculture on the sea bass (Dicentrarchus labrax)

Monitoring food quality is a critical task for analytical chemistry and an important way to preserve human health. Fish is a valuable source of highly digestible proteins and contains large amounts of polyunsaturated fatty acids and fat-soluble vitamins. Since the world's wild fish stocks are limited, farmed fish is nowadays proposed as an alternative to consumers. It is now emerging that the fish muscle protein content is assuming great importance from an aquaculture perspective. Many data have been collected on the physiology and biochemistry of fish muscle, but few proteomic studies are available on farmed fish. Application of proteomics to aquaculture may play a key role in the development of new farming strategies. In this paper, a proteomic approach based on SDS-PAGE separation of proteins, in situ protein hydrolysis, de novo sequencing of peptides by MALDI and ESI MS(2), protein identification, and relative quantitation of protein by denaturing capillary electrophoresis was coupled with the determination of fatty acids and metal ions content by GM-MS and ICPMS in farmed and wild sea bass filet. Our results show that aquaculture could induce significant chemical and biochemical differences in fish muscle that may have an impact on food quality.