Duodenal Ampulla Neuroendocrine Tumor with GISTs of the Proximal Jejunum: A Case Report

Neuroendocrine tumors (NEN) are a type of heterogenous, slow-growing tumors, that only in about half of the cases can be found in the gastrointestinal tract. Half of these is in the small intestine. The ampullary NENs are rare, accounting for less than 1% of gastroenteropancreatic NENs. Gastrointestinal stromal tumors (GIST) are a more common type of tumors of the gastrointestinal tract that consist of pacemaker cells. The occurrence of both tumors simultaneously is rare, but in patients with neurofibromatosis type 1, the co-existence of NEN and GIST is more often. Here we report a case of simultaneous occurrence of a well-differentiated NEN and a GIST in a patient without neurofibromatosis. Also, we provide a short review of the current knowledge and treatment strategies regarding these tumors.     

Further constructive results on interconnection and damping assignment control of mechanical systems: the Acrobot example

Interconnection and damping assignment passivity‐based control is a controller design methodology that achieves (asymptotic) stabilization of mechanical systems endowing the closed‐loop system with a Hamiltonian structure with a desired energy function—that qualifies as Lyapunov function for the desired equilibrium. The assignable energy functions are characterized by a set of partial differential equations that must be solved to determine the control law. A class of underactuation degree one systems for which the partial differential equations can be explicitly solved—making the procedure truly constructive—was recently reported by the authors. In this brief note, largely motivated by the interesting Acrobot example, we pursue this investigation for two degrees‐of‐freedom systems where a constant inertia matrix can be assigned. We concentrate then our attention on potential energy shaping and give conditions under which an explicit solution of the associated partial differential equation can be obtained. Using these results we show that it is possible to swing‐up the Acrobot from some configuration positions in the lower half plane, provided some conditions on the robot parameters are satisfied. Copyright © 2006 John Wiley & Sons, Ltd.     

Novel Reliable RF Capacitive MEMS Switches With Photodefinable Metal–Oxide Dielectrics

In this paper, the design, fabrication, and measurement of reliable low-cost capacitive radio-frequency microelectromechanical systems switches with a novel fabrication approach using direct photodefinable high-k metal oxides are presented. In this approach, a radiation-sensitive metal-organic precursor is deposited via spin coating and converted to a high-k metal oxide via ultraviolet exposure. Measurements of the bridge-type switches have been done up to 40 GHz. These switches are reliable (> 340 million cycles) and exhibited low insertion loss (about 0.3 dB at 20 GHz) and better isolation (about 24 dB at 20 GHz) at frequencies below the resonant frequency as compared to switches that are fabricated using a simple silicon nitride dielectric.     

Synthesis and antitumor molecular mechanism of agents based on amino 2-(3',4',5'-trimethoxybenzoyl)benzo[b]furan: inhibition of tubulin and induction of apoptosis

Induction of apoptosis is a promising strategy that could lead to the discovery of new molecules active in cancer chemotherapy. This property is generally observed when cells are treated with agents that target microtubules, dynamic structures that play a crucial role in cell division. Small molecules such as benzo[b]furans are attractive as inhibitors of tubulin polymerization. A new class of inhibitors of tubulin polymerization based on the 2-(3',4',5'-trimethoxybenzoyl)benzo[b]furan molecular skeleton, with the amino group placed at different positions on the benzene ring, were synthesized and evaluated for antiproliferative activity, inhibition of tubulin polymerization, and cell-cycle effects. The methoxy substitution pattern on the benzene portion of the benzo[b]furan moiety played an important role in affecting antiproliferative activity. In the series of 5-amino derivatives, the greatest inhibition of cell growth occurred if the methoxy substituent is placed at the C6 position, whereas C7 substitution decreases potency. The most promising compound in this series is 2-(3',4',5'-trimethoxybenzoyl)-3-methyl-5-amino-6-methoxybenzo[b]furan (3 h), which inhibits cancer cell growth at nanomolar concentrations (IC(50) =16-24 nM), and interacts strongly with tubulin by binding to the colchicine site. Sub-G(1) apoptotic cells in cultures of HL-60 and U937 cells were observed by flow cytometric analysis after treatment with 3 h in a concentration-dependent manner. We also show that compound 3 h induces apoptosis by activation of caspase-3, -8, and -9, and this is associated with cytochrome c release from mitochondria. The introduction of an α-bromoacryloyl group increased antiproliferative activity with respect to the parent amino derivatives.     

Staurosporine inhibits interferon alpha-induced gene expression in Friend erythroleukemia cells through a PKC independent pathway

Diabetes mellitus is associated with typical patterns of long term vascular complications which vary with the organ involved. The microvascular kidney disease (Olgemoller and Schleicher, 1993) is characterized by thickening of the capillary basement membranes and increased deposition of extracellular matrix components (ECM), while loss of microvessels with subsequent neovascularisation is predominant in the eye and peripheral nerves. On the other hand macrovascular disease is characterized by accelerated atherosclerosis. These complications are dependent on long term hyperglycemia. Specific biochemical pathways linking hyperglycaemia to microvascular changes were proposed: the polyol pathway (Greene et al., 1987), non-enzymatic glycation of proteins (Brownlee et al., 1988), glucose autooxidation and oxidative stress (Hunt et al., 1990), hyperglycemic pseudohypoxia (Williamson et al., 1993) enhanced activation of protein kinase C by de novo-synthesis of diacyl glycerol (Lee et al., 1989; DeRubertis and Craven 1994) and others. These pathways are not mutually exclusive (Larkins and Dunlop, 1992; Pfeiffer and Schatz, 1992). They may be linked to alterations in the synthesis of growth factors particularly since atherosclerosis and angioneogenesis are associated with increased proliferation of endothelial and smooth muscle cells. Increased synthesis of ECM components is stimulated by growth factors like transforming growth factor beta (TGF beta) (Derynck et al., 1984) and insulin-like growth factor I (IGF-I) (Moran et al., 1991). This review will summarize some of the recent evidence for an involvement of growth factors in diabetic vascular complications and will attempt to assign their emergence in the sequence of events leading to vascular complications.     

On the control of non-linear processes: An IDA–PBC approach

A high performance non-linear controller that exploits the properties of port-Hamiltonian systems to precisely define the interconnections and energy dissipations of non-linear processes is presented for a large class of chemical processes. The controller is derived from classical interconnection and damping assignment–passivity based control theory but an additional degree of freedom is introduced in the controller design by the use of “non-exact matching” closed-loop storage functions. By a proper closed-loop interconnection assignment the proposed controller achieves total decoupling between outputs and since no inversion of the process dynamics is made in the design it is equally applicable to minimum phase and nonminimum phase system. The controller design methodology is presented and stability conditions are stated. As illustrative example the proposed method is used to design controllers for a multiple-input/multiple-output non-isothermal continued stirred tank reactor that exhibits nonminimum phase behavior.     

A theoretical framework for simulated annealing

Simulated Annealing has been a very successful general algorithm for the solution of large, complex combinatorial optimization problems. Since its introduction, several applications in different fields of engineering, such as integrated circuit placement, optimal encoding, resource allocation, logic synthesis, have been developed. In parallel, theoretical studies have been focusing on the reasons for the excellent behavior of the algorithm. This paper reviews most of the important results on the theory of Simulated Annealing, placing them in a unified framework. New results are reported as well.