An Embedded Rule-Based Diagnostic Expert System in Ada

Ada is becoming an increasingly popular programming language for large Government-funded software projects. Ada with it portability, transportability, and maintainability lends itself well to today's complex programming environment. In addition, expert systems have also assumed a growing role in providing human-like reasoning capability expertise for computer systems. The integration is discussed of expert system technology with Ada programming language, especially a rule-based expert system using an ART-Ada (Automated Reasoning Tool for Ada) system shell. NASA Lewis was chosen as a beta test site for ART-Ada. The test was conducted by implementing the existing Autonomous Power EXpert System (APEX), a Lisp-based power expert system, in ART-Ada. Three components, the rule-based expert systems, a graphics user interface, and communications software make up SMART-Ada (Systems fault Management with ART-Ada). The rules were written in the ART-Ada development environment and converted to Ada source code. The graphics interface was developed with the Transportable Application Environment (TAE) Plus, which generates Ada source code to control graphics images. SMART-Ada communicates with a remote host to obtain either simulated or real data. The Ada source code generated with ART-Ada, TAE Plus, and communications code was incorporated into an Ada expert system that reads the data from a power distribution test bed, applies the rule to determine a fault, if one exists, and graphically displays it on the screen. The main objective, to conduct a beta test on the ART-Ada rule-based expert system shell, was achieved. The system is operational. New Ada tools will assist in future successful projects. ART-Ada is one such tool and is a viable alternative to the straight Ada code when an application requires a rule-based or knowledge-based approach

On air: Evaluating streaming MPEG4 video performance over wireless networks [abstract]

Abstract only availableThere is not a clear consensus on how open-standard video streaming technologies perform across wireless computer networks. Wireless networking technologies have become nearly ubiquitous, particularly in residential networks, but consumers may not realize that the performance of wireless networks may differ significantly from that of wired networks. Advances in video compression and wireless network bandwidth may allow for the ability to stream higher-quality video content than previously possible. We seek to evaluate how video content, encoded by the MPEG4 codec, performs when streamed across simulated residential wired and wireless networks. We are interested in how the transmission of the video across the network link affects the subjective and objective appearance of the video on the client computer. Our network testbed comprises nine typical desktop computers equipped with a modified version of Videolan Client to playback a network video stream, provided by a server running the Darwin Streaming Server from Apple Inc., connected using wired Ethernet connections and 802.11b, 802.11g, and draft 802.11n version 1.0 wireless connections. Each client was monitored while receiving a sample of raw video data encoded at one of several common bitrates to note any lost content. Each client saved a copy of the video locally for later comparison with the original using the PSNR (Peak Signal to Noise Ratio) and SSIM (Structural SIMilarity) metrics. Looking strictly at established wireless standards (802.11b and g), we found that they are not capable of streaming multiple ITU-R BT.709 high definition video streams across a wireless network link. Wired and draft 802.11n wireless connections did prove robust enough to handle multiple high definition video streams concurrently. Hopefully, our work will lead to a better understanding of the technical issues, performance, and trade-offs in home networking, thus facilitating the rapid deployment of advanced home networking services and applications

Attention Shaping: a Reward-Based Learning Method to Enhance Skills Training Outcomes in Schizophrenia

Disturbances in sustained attention commonly interfere with the ability of persons with schizophrenia to benefit from evidence-based psychosocial treatments. Cognitive remediation interventions have thus far demonstrated minimal effects on attention, as have medications. There is thus a gap between the existence of effective psychosocial treatments and patients’ ability to effectively engage in and benefit from them. We report on the results of a multisite study of attention shaping (AS), a behavioral intervention for improving attentiveness and learning of social skills among highly distractible schizophrenia patients. Patients with chronic schizophrenia who were refractory to skills training were assigned to receive either the UCLA Basic Conversation Skills Module (BCSM) augmented with AS (n = 47) or in the standard format (n = 35). AS, a reward-based learning procedure, was employed to facilitate patients’ meeting clearly defined and individualized attentiveness and participation goals during each session of a social skills training group. Primary outcome measures were observational ratings of attentiveness in each session and pre- and post-BCSM ratings of social skill and symptoms. Patients receiving social skills training augmented with AS demonstrated significantly more attentiveness in group sessions and higher levels of skill acquisition; moreover, significant relationships were found between changes in attentiveness and amount of skills acquired. Changes in attentiveness were unrelated to level or change in antipsychotic medication dose. AS is an effective example of supported cognition, in that cognitive abilities are improved within the environmental context where the patient is experiencing difficulty, leading to gains in both attention and functional outcome

Attention Shaping: a Reward-Based Learning Method to Enhance Skills Training Outcomes in Schizophrenia

Disturbances in sustained attention commonly interfere with the ability of persons with schizophrenia to benefit from evidence-based psychosocial treatments. Cognitive remediation interventions have thus far demonstrated minimal effects on attention, as have medications. There is thus a gap between the existence of effective psychosocial treatments and patients’ ability to effectively engage in and benefit from them. We report on the results of a multisite study of attention shaping (AS), a behavioral intervention for improving attentiveness and learning of social skills among highly distractible schizophrenia patients. Patients with chronic schizophrenia who were refractory to skills training were assigned to receive either the UCLA Basic Conversation Skills Module (BCSM) augmented with AS (n = 47) or in the standard format (n = 35). AS, a reward-based learning procedure, was employed to facilitate patients’ meeting clearly defined and individualized attentiveness and participation goals during each session of a social skills training group. Primary outcome measures were observational ratings of attentiveness in each session and pre- and post-BCSM ratings of social skill and symptoms. Patients receiving social skills training augmented with AS demonstrated significantly more attentiveness in group sessions and higher levels of skill acquisition; moreover, significant relationships were found between changes in attentiveness and amount of skills acquired. Changes in attentiveness were unrelated to level or change in antipsychotic medication dose. AS is an effective example of supported cognition, in that cognitive abilities are improved within the environmental context where the patient is experiencing difficulty, leading to gains in both attention and functional outcome

Biphasic Elimination of Tenofovir Diphosphate and Nonlinear Pharmacokinetics of Zidovudine Triphosphate in a Microdosing Study

Objective: Phase 0 studies can provide initial pharmacokinetics (PKs) data in humans and help to facilitate early drug development, but their predictive value for standard dosing is controversial. To evaluate the prediction of microdosing for active intracellular drug metabolites, we compared the PK profile of 2 antiretroviral drugs, zidovudine (ZDV) and tenofovir (TFV), in microdose and standard dosing regimens. Study Design: We administered a microdose (100 μg) of [superscript 14]C-labeled drug (ZDV or tenofovir disoproxil fumarate) with or without a standard unlabelled dose (300 mg) to healthy volunteers. Both the parent drug in plasma and the active metabolite, ZDV-triphosphate (ZDV-TP) or TFV-diphosphate (TFV-DP) in peripheral blood mononuclear cells (PBMCs) and CD4[superscript +] cells were measured by accelerator mass spectrometry. Results: The intracellular ZDV-TP concentration increased less than proportionally over the dose range studied (100 μg–300 mg), whereas the intracellular TFV-DP PKs were linear over the same dose range. ZDV-TP concentrations were lower in CD4[superscript +] cells versus total PBMCs, whereas TFV-DP concentrations were not different in CD4[superscript +] cells and PBMCs. Conclusions: Our data were consistent with a rate-limiting step in the intracellular phosphorylation of ZDV but not TFV. Accelerator mass spectrometry shows promise for predicting the PK of active intracellular metabolites of nucleosides, but nonlinearity of PK may be seen with some drugs.Johns Hopkins University (Institute for Clinical and Translational Research CTSA Grant UL1-RR025005

Bloqueio Atrioventricular Paroxístico como Causa de Síncope em Crianças sem Cardiopatia Congênita

Histórico: A síncope causada por bloqueio atrioventricular (AV) paroxístico, definido como bloqueio de segundo ou terceiro grau transitório, raramente é relatada em pacientes pediátricos sem cardiopatias congênitas. Métodos: Realizou-se uma revisao do banco de dados de arritmias da nossa instituiçao, de janeiro de 1988 a janeiro de 2007, para identificar todos os pacientes com menos de 18 anos de idade com anatomia cardíaca normal e episódios de síncope associados a bloqueio AV paroxístico. Informaçoes demográficas e clínicas foram coletadas. Resultados: Foram identificados seis pacientes, cinco do sexo feminino, com idade média de 9,3 ± 4,4 anos, que haviam sofrido episódios de síncope durante 5,6 ± 3,3 anos, em média, antes do diagnóstico (Tabela 1). Todos foram submetidos a exame físico, eletrocardiograma e ecocardiograma. Os resultados dos exames laboratoriais, inclusive para doença de Lyme, foram negativos. Nenhum deles recebia medicaçao capaz de interferir na conduçao AV nodal. Cinco dos seis episódios relatados foram atípicos para síncope vasovagal (com exceçao do paciente 6). Todos os pacientes tiveram bloqueio AV paroxístico documentado em monitor cardíaco ou gravador de Holter de 24 horas, registrado durante a síncope em pacientes internados. Houve manutençao ou aceleraçao do ritmo sinusal durante os episódios de síncope em todos os pacientes (ritmo atrial médio de 107 ± 37 bpm). Os seis pacientes receberam o implante de marcapasso transvenoso permanente, com a resoluçao dos sintomas durante um acompanhamento médio de 5,2 ± 6,3 anos. Conclusao: O bloqueio AV paroxístico é um achado raro em pacientes pediátricos, mas deve ser considerado uma etiologia possível naqueles que apresentam episódios atípicos de síncope vasovagal. A terapia utilizando marcapassos preveniu novas ocorrências em todos os seis pacientes

Bloqueio Atrioventricular Paroxístico como Causa de Síncope em Crianças sem Cardiopatia Congênita

Histórico: A síncope causada por bloqueio atrioventricular (AV) paroxístico, definido como bloqueio de segundo ou terceiro grau transitório, raramente é relatada em pacientes pediátricos sem cardiopatias congênitas. Métodos: Realizou-se uma revisao do banco de dados de arritmias da nossa instituiçao, de janeiro de 1988 a janeiro de 2007, para identificar todos os pacientes com menos de 18 anos de idade com anatomia cardíaca normal e episódios de síncope associados a bloqueio AV paroxístico. Informaçoes demográficas e clínicas foram coletadas. Resultados: Foram identificados seis pacientes, cinco do sexo feminino, com idade média de 9,3 ± 4,4 anos, que haviam sofrido episódios de síncope durante 5,6 ± 3,3 anos, em média, antes do diagnóstico (Tabela 1). Todos foram submetidos a exame físico, eletrocardiograma e ecocardiograma. Os resultados dos exames laboratoriais, inclusive para doença de Lyme, foram negativos. Nenhum deles recebia medicaçao capaz de interferir na conduçao AV nodal. Cinco dos seis episódios relatados foram atípicos para síncope vasovagal (com exceçao do paciente 6). Todos os pacientes tiveram bloqueio AV paroxístico documentado em monitor cardíaco ou gravador de Holter de 24 horas, registrado durante a síncope em pacientes internados. Houve manutençao ou aceleraçao do ritmo sinusal durante os episódios de síncope em todos os pacientes (ritmo atrial médio de 107 ± 37 bpm). Os seis pacientes receberam o implante de marcapasso transvenoso permanente, com a resoluçao dos sintomas durante um acompanhamento médio de 5,2 ± 6,3 anos. Conclusao: O bloqueio AV paroxístico é um achado raro em pacientes pediátricos, mas deve ser considerado uma etiologia possível naqueles que apresentam episódios atípicos de síncope vasovagal. A terapia utilizando marcapassos preveniu novas ocorrências em todos os seis pacientes

Variable sizes of Escherichia coli chemoreceptor signaling teams

Like many sensory receptors, bacterial chemotaxis receptors form clusters. In bacteria, large-scale clusters are subdivided into signaling teams that act as ‘antennas' allowing detection of ligands with remarkable sensitivity. The range of sensitivity is greatly extended by adaptation of receptors to changes in concentrations through covalent modification. However, surprisingly little is known about the sizes of receptor signaling teams. Here, we combine measurements of the signaling response, obtained from in vivo fluorescence resonance energy transfer, with the statistical method of principal component analysis, to quantify the size of signaling teams within the framework of the previously successful Monod–Wyman–Changeux model. We find that size of signaling teams increases 2- to 3-fold with receptor modification, indicating an additional, previously unrecognized level of adaptation of the chemotaxis network. This variation of signaling-team size shows that receptor cooperativity is dynamic and likely optimized for sensing noisy ligand concentrations

Enhanced ordering in length-polydisperse carbon nanotube solutions at high concentrations as revealed by small angle X-ray scattering

Carbon nanotubes (CNTs) are stiff, all-carbon macromolecules with diameters as small as one nanometer and few microns long. Solutions of CNTs in chlorosulfonic acid (CSA) follow the phase behavior of rigid rod polymers interacting via a repulsive potential and display a liquid crystalline phase at sufficiently high concentration. Here, we show that small-angle X-ray scattering and polarized light microscopy data can be combined to characterize quantitatively the morphology of liquid crystalline phases formed in CNT solutions at concentrations from 3 to 6.5 % by volume. We find that upon increasing their concentration, CNTs self-assemble into a liquid crystalline phase with a pleated texture and with a large inter-particle spacing that could be indicative of a transition to higher-order liquid crystalline phases. We explain how thermal undulations of CNTs can enhance their electrostatic repulsion and increase their effective diameter by an order of magnitude. By calculating the critical concentration, where the mean amplitude of undulation of an unconstrained rod becomes comparable to the rod spacing, we find that thermal undulations start to affect steric forces at concentrations as low as the isotropic cloud point in CNT solutions

Primary breast lymphoma: a consideration in an HIV patient when a mass is discovered by screening mammography: a case report

Primary Breast lymphoma is a rare lesion that has been reported in patients without HIV. However, Primary Breast lymphoma occurring in a patient with HIV has rarely been reported despite the fact that HIV infection is known to increase the propensity to develop certain types of lymphoma. We report a case of an HIV patient with breast lymphoma that was discovered by screening mammography while presenting our argument for more cautionary management in this patient population