The importance of thyroid hormones in the regulation of development, growth, and energy metabolism is well known. Over the last decades, mass spectrometry has been extensively used to investigate thyroid hormone metabolism and to discover and characterize new molecules involved in thyroid hormones production, such as thyrotropin-releasing hormone. In the earlier period, the quantification methods, usually based on gas chromatography–mass spectrometry, were complicated and time consuming. They were mainly focused on basic research, and were not suitable for clinical diagnostics on a routine basis. The development of the modern mass spectrometers, mainly coupled to liquid chromatography, enabled simpler sample preparation procedures, and the accurate quantification of thyroid hormones, of their precursors, and of their metabolites in biological fluids, tissues, and cells became feasible. Nowadays, molecules of physiological and pathological interest can be assayed also for diagnostic purposes on a routine basis, and mass spectrometry is slowly entering the clinical laboratory. This review takes stock of the advancements in the field of thyroid metabolism that were carried out with mass spectrometry, with special focus on the use of this technique for the quantification of molecules involved in thyroid diseases. 相似文献
Granular materials segregate spontaneously due to differences in particle size, shape, density and flow behaviour. In this paper we experimentally investigate density-difference-driven segregation for a range of density ratios and a range of heavy particle concentrations. The experiments are conducted in an annular shear cell with rotating bumpy bottom that yields an exponential shear profile. The cell is initially filled with a layer of light particles and an upper layer of heavier grains and, on top, a load provides confinement. The segregation process is filmed through the transparent side-wall with a camera, and the evolution of particle concentration in space and time is evaluated by means of post-processing image analysis. We also propose a continuum-approach to model density-driven segregation. We use a segregation-diffusion transport equation, constitutive relations for effective viscosity and friction coefficient, and a segregation velocity analogous to the Stokes’ law. The model, which is validated by comparison with experimental findings, can successfully predict density-driven segregation at different density ratios and volumetric fraction. 相似文献
This paper considers the problem of optimizing the operation of Indirect Adiabatic Cooling (IAC) systems with application to data centers. Optimal operation is achieved when the required cooling demand is satisfied at the minimum energy cost. For this purpose, we design a supervisory control system, where the higher layer determines the optimal set-points for the local controllers by employing an Extremum Seeking Control (ESC) scheme. In particular, we consider a Newton-like phasor ESC, which augments the derivative estimator underlying the phasor approach to capture also the Hessian of the plant index and then it uses these estimates to steer the system along a Newton-like direction. The effectiveness of the considered approach is tested in simulation by exploiting a Matlab-based simulation environment including an IAC system and a computer room. 相似文献
Automated storage/retrieval systems (AS/RSs) are a combination of equipment and controls which automatically handle, store
and retrieve materials (components, tools, raw material and subassemblies) with great speed and accuracy. Consequently, they
are widely used in industrial companies to manage products with cost-effective utilization of time, space and equipment. This
paper presents a multi-parametric dynamic model of a product-to-picker storage system with class based storage allocation
of products. Thousands of what-if scenarios are simulated in order to measure the impact of alternative design and operating
configurations on the expected system performance and to identify the most critical factors and combinations of factors affecting
the response of the system. Class based storage proves to be a very effective way of both reducing the picking cycle time
and maximizing the throughput of the system. The rapid effectiveness of visual interactive simulation (VIS) in supporting
the design (redesign) and control of new (existing) warehouses emerges, responding to the need for flexibility which modern
companies need in order to adapt to strongly changing operating conditions quickly. 相似文献
We present here the first of a series of video-games designed for teaching fundamentals of computer science to university students. We built the game as an adventure inside a dungeon, which aims at reproducing the topology of a Unix file system. Inside the different rooms, the players can learn how to use several Unix commands, from simple file system actions to complex text manipulations, to complete the quests and win the game. We performed a user test on a class of B.Sc. students at the University of Cagliari. The results show a good acceptance of the game metaphor and its effectiveness in supporting the learning process. We plan to expand this game and to design similar games for teaching object-oriented programming and algorithms and data structures.
Low carrier mobility and lifetime in semiconductor polymers are some of the main challenges facing the field of organic photovoltaics (OPV) in the quest for efficient devices with high current density. Finding novel strategies such as device structure engineering is a key pathway toward addressing this issue. In this work, the light absorption and carrier collection of OPV devices are improved by employment of ZnO nanowire (NW) arrays with an optimum NW length (50 nm) and antireflection (AR) film with nanocone structure. The optical characterization results show that ZnO NW increases the transmittance of the electron transporting layer as well as the absorption of the polymer blend. Moreover, the as‐deposited polymer blend on the ZnO NW array shows better charge transfer as compared to the planar sample. By employing PC70BM:PV2000 as a promising air‐stable active‐layer, power conversion efficiencies of 9.8% and 10.1% are achieved for NW devices without and with an AR film, indicating 22.5% and 26.2% enhancement in PCE as compared to that of planar device. Moreover, it is shown that the AR film enhances the water‐repellent ability of the OPV device. 相似文献
This paper introduces a new model for Non‐Conformity Management, aimed at overcoming the limitations occurring when dealing with Non‐Conformities through traditional methods like Root Cause Analysis. The need to suggest a new approach to Non‐Conformities Management is connected to those situations where a large variety of Non‐Conformities is recorded, with a significant number of low‐impacting ones; addressing them directly through methods like Root Cause Analysis would often be not economically viable. In this context, the paper discusses Holistic Non‐Conformities Reduction (HNCR) approach as a suitable option to address this kind of business situations. In particular, the contribution of this paper is related to the development of HNCR model and the evaluation of how to properly structure the model and the flow that shall be followed. By clustering Non‐Conformities into flexible categories to be easily modified, expanded and rearranged through time, the HNCR model allows to identify new critical Non‐Conformity families, otherwise hardly detectable. A proof of concept relative to HNCR deployment is presented: 2 different scenarios are introduced, the first being the Non‐Conformities management within the extended supply chain of a large pharmaceutical distribution centre, while the second deals with Non‐Conformities in the context of a company's new programs development. 相似文献
Electroactive ionic gel/metal nanocomposites are produced by implanting supersonically accelerated neutral gold nanoparticles into a novel chemically crosslinked ion conductive soft polymer. The ionic gel consists of chemically crosslinked poly(acrylic acid) and polyacrylonitrile networks, blended with halloysite nanoclays and imidazolium‐based ionic liquid. The material exhibits mechanical properties similar to that of elastomers (Young's modulus ≈ 0.35 MPa) together with high ionic conductivity. The fabrication of thin (≈100 nm thick) nanostructured compliant electrodes by means of supersonic cluster beam implantation (SCBI) does not significantly alter the mechanical properties of the soft polymer and provides controlled electrical properties and large surface area for ions storage. SCBI is cost effective and suitable for the scaleup manufacturing of electroactive soft actuators. This study reports the high‐strain electromechanical actuation performance of the novel ionic gel/metal nanocomposites in a low‐voltage regime (from 0.1 to 5 V), with long‐term stability up to 76 000 cycles with no electrode delamination or deterioration. The observed behavior is due to both the intrinsic features of the ionic gel (elasticity and ionic transport capability) and the electrical and morphological features of the electrodes, providing low specific resistance (<100 Ω cm?2), high electrochemical capacitance (≈mF g?1), and minimal mechanical stress at the polymer/metal composite interface upon deformation. 相似文献