Radiofluorinated Pyrimidine‐2,4,6‐triones as Molecular Probes for Noninvasive MMP‐Targeted Imaging

Matrix metalloproteinases (MMPs) are zinc‐ and calcium‐dependent endopeptidases. Representing a subfamily of the metzincin superfamily, MMPs are involved in the proteolytic degradation of components of the extracellular matrix. Unregulated MMP expression, MMP dysregulation and locally increased MMP activity are common features of various diseases, such as cancer, atherosclerosis, stroke, arthritis, and others. Therefore, activated MMPs are suitable biological targets for the specific visualization of such pathologies, in particular by using radiolabeled MMP inhibitors (MMPIs). The aim of this work was to develop a radiofluorinated molecular probe for noninvasive in vivo imaging for the detection of up‐regulated levels of activated MMPs in the living organism. Fluorinated MMPIs ( 26 , 31 and 38 ) based on the pyrimidine‐2,4,6‐trione lead structure RO 28‐2653 ( 1 ) were synthesized, and their MMP inhibition potency was evaluated in vitro. The radiosynthesis and the in vivo biodistribution of the first ¹⁸F‐labeled prototype, MMP‐targeted tracer [¹⁸F] 26 , suitable for molecular imaging by means of positron emission tomography (PET) were realized.     

Research Needs and Challenges in Application of Computer and Information Sciences for Industrial Engineering

By invitation from the Editor of IIE Transactions, a research forum was established in 1987 to develop and prepare this article. The objective: to write on the directions, needs and challenges for research by the IE com-munity in applying computer and information sciences. The motivation: realizing the major advancements in computer and information sciences in the recent decade and their significant impact on the IE profession, it is vital to examine how IE research activities can respond effectively to current and emerging needs. This article is viewed as a useful contribution to such an examination.

Forum members were invited from academia, government and industry based on their experience in and commitment to research in this area. The forum was chaired by Shimon Y. Nof and the members are the co-authors of this article.

Forum members communicated and deliberated throughout 1987 and met for a review and planning session dur-ing the IIE Conference in Washington, D.C. in May, 1987 (Forum, 1987). The following article summarizes the contributions and recommendations of the forum members, and was reviewed by four guest reviewers. The re-viewers, invited by the Editor, have provided comments that have been incorporated into this article     

GSM phase 2+ general packet radio service GPRS: Architecture, protocols, and air interface

Selective packet dropping policies have been used to reduce congestion and transmission of traffic that would inevitably be retransmitted. For data applications using best-effort services, packet dropping policies (PDPs) are congestion management mechanisms implemented at each intermediate node that decide, reactively or proactively, to drop packets to reduce congestion and free up precious buffer space. While the primary goal of PDPs is to avoid or combat congestion, the individual PDP designs can significantly affect application throughput, network utilization, performance fairness, and synchronization problems with multiple Transmission Control Protocol (TCP) connections. Scalability and simplicity are also important design issues. This article surveys the most important selective packet dropping policies that have been designed for best-effort traffic in ATM and IP networks, providing a comprehensive comparison between the different mechanisms.     

Numerical simulation of the effect of maldistribution in a fixed bed adsorber

The paper deals with the modeling of the effect of maldistribution in pollutant abatementtrichloroethylene(TCE)concerning low concentration(10~(-5)-10~(-8)kg·m~(-3))adsorption in an adsorber.Such a concentration range is rather typical in many an environmental application.Isotherms andbreakthrough curves for TCE adsorption are obtained both for a commercial activated carbonSorbonorit 4 and a laboratory adsorber of d_B/d_P=11.Two two-dimensional nonequilibrium isothermalmodels are developed to describe the mass transfer in the fixed bed taking into account the effect ofmaldistribution.It is found the simulation results with maldistribution are in very good agreementwith the experimental findings.Low concentration TCE adsorption in a fixed bed of activated carbonis found to be strongly influenced by maldistribution.The non-uniform distributions of concentrationand loading of the pollutant in the adsorber are predicted by the model.Maldistribution and its ef-fect on the initial breakthrough of TCE in the