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101.
OBJECTIVE: To assess the developmental effects of desipramine (DMI) treatment on the electrocardiogram (ECG), we investigated serum concentrations of DMI ([DMI]), and its major active metabolite 2-hydroxydesipramine ([OHDMI]) and ECG parameters. METHODS: ECGs and [DMI] and [OHDMI] were analyzed from 50 children, 39 adolescents, and 30 adult psychiatric patients receiving DMI. RESULTS: There were modest overall correlations between [DMI], [OHDMI], or [OHDMI+DMI], and the PR and QRS intervals when data from all 119 subjects were pooled. Within the pediatric age groups there were no significant associations between serum drug levels and heart rate or conduction intervals; and in all subjects with ECG abnormalities, there were some findings of higher [DMI], [OHDMI], and [OHDMI+DMI]. CONCLUSIONS: These findings indicate that only modest associations of [DMI] and [OHDMI] with ECG conduction intervals were found, and are not likely to be clinically significant in any of the age groups studied. Compared with adults, children and adolescents do not appear to be at increased risks for ECG changes related to DMI treatment or to circulating concentrations of [DMI] or [OHDMI].  相似文献   
102.
A number of identifiable immunological parameters can influence the elicitation and regulation of antigen-specific inflammatory responses to immunogenic epitopes. Injection of antigen in vivo can lead to the activation of type IV hypersensitivity responses, or to the induction of immunological tolerance to that antigen. We have used the hapten trinitrophenol as a model system for studying the factors which influence the generation and regulation of hypersensitivity responses to immunogenic epitopes in vivo. The generation of hypersensitivity or tolerance to trinitrophenyl depends on a number of immunological factors, including the form of the antigen, the route of immunization, and the presence of immune complexes of antibody and antigen on the surface of the antigen-presenting cell. Immunization with trinitrophenyl resulting in unresponsiveness can be the result of either the inability to prime inflammatory cells in vivo or the induction of suppressor T cells.  相似文献   
103.
A time-division multiplex (t.d.m.) and a frequency-division multiple (f.d.m.) system may be interconnected by means of gates and lowpass filters. The use of digital filters (d.f.s) for this purpose appears attractive when the t.d.m. system uses pulse-code modulation (p.c.m.), because digital-analogue and analogue-digital conversion are unnecessary at the interface between the d.f. and the p.c.m. system. The problems involved in applying d.f.s in this application are discussed. It is concluded that the interconnection of p.c.m. systems with f.d.m. systems using quite low carrier frequencies requires the development of digital circuits operating at several hundred megahertz.  相似文献   
104.
A new design for digital automatic gain control for p.c.m. telephony is presented. This new design is capable of processing 30 speech channels. It avoids putting highest gain where there is no speech. It has manual and automatic facilities.  相似文献   
105.
Microwave fixed links play a vital role supporting infrastructure requirements in telecommunications. As the demand for their use increases, particularly in providing backhaul for mobile networks, it is important that the microwave spectrum is exploited efficiently. This paper investigates the use of equipment selection algorithms within the microwave fixed-links frequency assignment problem. Standard data-rates are often supported by two alternative radio system types; one utilising a relatively lower-order modulation scheme and the other using relatively higher-order modulation. The higher-order modulation radios use less bandwidth to achieve the same data rate, but at the expense of higher wanted signal levels and lower interference thresholds. Hence while higher-order modulation is the more spectrally efficient option for an individual link considered in isolation, it may not be the most efficient when the wider network is taken into account. In this paper we provide a new model for the fixed link frequency assignment problem with equipment selection, formulated as an integer program, and investigate the nature of the trade-off between local and global spectral efficiency on a range of representative data.  相似文献   
106.
The computer industry is currently examining the use of strong synchronization operations such as double compare-and-swap (DCAS) as a means of supporting non-blocking synchronization on future multiprocessor machines. However, before such a strong primitive will be incorporated into hardware design, its utility needs to be proven by developing a body of effective non-blocking data structures using DCAS. As part of this effort, we present two new linearizable non-blocking implementations of concurrent deques using the DCAS operation. The first uses an array representation, and improves on previous algorithms by allowing uninterrupted concurrent access to both ends of the deque while correctly handling the difficult boundary cases when the deque is empty or full. The second uses a linked-list representation, and is the first non-blocking, dynamically-sized deque implementation. It too allows uninterrupted concurrent access to both ends of the deque. We have proved these algorithms correct with the aid of a mechanical theorem prover; we describe these proofs in the paper.  相似文献   
107.
We describe a novel phase-sensing and control system, based on phase-contrast imaging, operating within a linear external cavity laser consisting of 18 GaAlAs edge-emitting gain stripes. The system is used to achieve single-spatial-mode operation and diffraction-limited output from the linear cavity, which uses diffractive coupling at a Talbot plane to achieve coherent operation.  相似文献   
108.
Parker  John R.  Flood  Ian D.  Carter  Glyn D. 《Wireless Networks》2021,27(2):1103-1110
Wireless Networks - This study has investigated the mitigations necessary for successful compatibility between International Mobile Telecommunications (IMT) services and Fixed Satellite Service...  相似文献   
109.
Various biodiesel feedstocks were evaluated using gas chromatography–mass spectrometry data combined with unsupervised chemometric methods of analysis. Peak areas of the fatty acid methyl esters (FAMEs) present in the biodiesel feedstocks (soybean oil, canola oil, waste grease, animal tallow, etc.) were utilized. The importance of chromatographic parameters, such as temperature program and column polarity, was examined with respect to the clustering that was observed using principal component analysis (PCA) and hierarchical cluster analysis (HCA). Biodiesels in this study clustered based on feedstock type regardless of temperature program or column type, as long as FAME isomers were resolved from one another. As such, the number and type of FAME components required to observe this clustering was investigated further. In general, the minor components in the sample did not provide improved clustering and thus did not need to be included. In addition, data from various temperature programs or column types were combined to yield similar clustering, showing potential versatility in analyzing similar samples across laboratories using different columns and column properties. Overall, we determined that (1) minor FAME components are non-essential for feedstock identification and (2) PCA and HCA clustering is based on feedstock, regardless of column selection, so long as resolution of FAME isomers is achieved.  相似文献   
110.
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