Establishing reliability goals for naval major caliber ammunition

In this study, we describe a decision process for establishing the threshold reliabilities for components of naval major caliber ammunition. A measure of reliability performance is described which relates directly to the weapons system's performance in a naval gunfire support environment. We use a simulation model to establish this relationship, a regression metamodel to estimate its parameters, and a simple decision process to specify component reliability thresholds which ensure that the ammunition is mission effective. We present this paper as an example of the integration of discrete event dynamic system analysis within a decision processNaval Weapons Support Center (NWSC), Crane, Indianahttp://archive.org/details/establishingreli00bailN4802991WXPM454NAApproved for public release; distribution is unlimited

Use of Photopolymerizable Membranes Based on Polyacrylamide Hydrogels for Enzymatic Microsensor Construction

The construction of enzymatic microsensors based on semiconductor technology and photo-curable membranes is reported in this work. A planar three-microelectrode cell and a pH-sensitive Ion Selective Field-Effect Transistor (ISFET) with Si3N4 membrane have been used as transducers for glucose and urea measurements, respectively. Polyacrylamide has been employed as matrix material for the immobilization by entrapment of the enzyme. This hydrogel permits the membrane deposition and patterning by photolithographic techniques which are compatible with semiconductor technology. It also provides reproducible and thin membranes due to the possible automatization of the whole process. In order to improve the long-term stability of the sensor, the introduction of glutaraldehyde in the membrane for inter-enzyme cross-linking has been tested. Both methods of membrane preparation, with the cross-linker and without it, have been compared observing an increase of the long-term stability of around two times for glucose and urea sensors. The response characteristics of glucose and urea sensors using several membrane preparations have been studied under different measurement conditions. A sensitivity of 45-67 nA mM-1 in a linear range 4 x 10-3-1 mM depending on the membrane thickness and enzyme concentration has been observed for the amperometric glucose sensor. A sensitivity from 50 to 58 mV per decade in a concentration range 0.2-8 mM urea depending on the membrane preparation has been obtained for the urea enzymatic Field-Effect Transistor (ENFET) sensor

In Vitro and In Vivo Efficacies of the New Triazole Albaconazole against Cryptococcus neoformans

The activity of albaconazole (UR-9825; J. Uriach & Cía. S.A., Barcelona, Spain) was compared to that of fluconazole against 12 isolates of Cryptococcus neoformans in vitro and against 1 isolate in vivo in a rabbit model of cryptococcal meningitis. Albaconazole was 100-fold more potent in vitro than fluconazole on a per-weight basis and was fungicidal at potentially relevant concentrations for two isolates. MICs ranged from ≤0.0012 to 1.25 μg/ml, with the MICs for most isolates being between 0.039 and 0.156 μg/ml. Isolates were from human immunodeficiency virus (HIV)-infected and non-HIV-infected patients and were of serotypes A, B, and C; and the fluconazole MICs for some of the isolates were elevated. Infected rabbits were treated with either fluconazole or albaconazole at dosages ranging from 5 to 80 mg/kg of body weight/day. The peak concentrations of albaconazole in serum and cerebrospinal fluid (CSF) averaged 4.14 and 0.62 μg/ml, respectively, in animals receiving 80 mg/kg/day. Comparison of the concentrations in serum and CSF suggested a level of CSF penetration of approximately 15%. Despite limited penetration into the subarachnoid space, at all three doses tested albaconazole was as effective as fluconazole for the treatment of cryptococcal meningitis in rabbits

Data Assimilation for Full 4D PC-MRI Measurements: Physics-Based Denoising and Interpolation

Phase-Contrast Magnetic Resonance Imaging (PC-MRI) surpasses all other imaging methods in quality and completeness for measuring time-varying volumetric blood flows and has shown potential to improve both diagnosis and risk assessment of cardiovascular diseases. However, like any measurement of physical phenomena, the data are prone to noise, artefacts and has a limited resolution. Therefore, PC-MRI data itself do not fulfil physics fluid laws making it difficult to distinguish important flow features. For data analysis, physically plausible and high-resolution data are required. Computational fluid dynamics provides high-resolution physically plausible flows. However, the flow is inherently coupled to the underlying anatomy and boundary conditions, which are difficult or sometimes even impossible to adequately model with current techniques. We present a novel methodology using data assimilation techniques for PC-MRI noise and artefact removal, generating physically plausible flow close to the measured data. It also allows us to increase the spatial and temporal resolution. To avoid sensitivity to the anatomical model, we consider and update the full 3D velocity field. We demonstrate our approach using phantom data with various amounts of induced noise and show that we can improve the data while preserving important flow features, without the need of a highly detailed model of the anatomy.</p

Visual analysis of tumor control models for prediction of radiotherapy response

In radiotherapy, tumors are irradiated with a high dose, while surrounding healthy tissues are spared. To quantify the probability that a tumor is effectively treated with a given dose, statistical models were built and employed in clinical research. These are called tumor control probability (TCP) models. Recently, TCP models started incorporating additional information from imaging modalities. In this way, patient-specific properties of tumor tissues are included, improving the radiobiological accuracy of models. Yet, the employed imaging modalities are subject to uncertainties with significant impact on the modeling outcome, while the models are sensitive to a number of parameter assumptions. Currently, uncertainty and parameter sensitivity are not incorporated in the analysis, due to time and resource constraints. To this end, we propose a visual tool that enables clinical researchers working on TCP modeling, to explore the information provided by their models, to discover new knowledge and to confirm or generate hypotheses within their data. Our approach incorporates the following four main components: (1) It supports the exploration of uncertainty and its effect on TCP models; (2) It facilitates parameter sensitivity analysis to common assumptions; (3) It enables the identification of inter-patient response variability; (4) It allows starting the analysis from the desired treatment outcome, to identify treatment strategies that achieve it. We conducted an evaluation with nine clinical researchers. All participants agreed that the proposed visual tool provides better understanding and new opportunities for the exploration and analysis of TCP modeling

In Vitro Antifungal Activities of the New Triazole UR-9825 against Clinically Important Filamentous Fungi

We used a modified reference microdilution method (the M-38P method) to evaluate the in vitro activities of the new triazole UR-9825 in comparison with those of amphotericin B against 77 strains of opportunistic filamentous fungi. UR-9825 was clearly more active than amphotericin B against all fungi except Fusarium solani and Scytalidium spp. Notably, UR-9825 had low MICs for Aspergillus fumigatus and Paecilomyces lilacinus (MICs at which 90% of isolates are inhibited, 0.125 μg/ml for both species)

Discovery of a Novel Broad-Spectrum Antifungal Agent Derived from Albaconazole

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