Search

This paper describes a new type of power amplifier (PA) module with a predistortion function and can be applied to N-CDMA (narrow-band CDMA system defined in IS-95B Standard) handset terminals. Distortion compensation technology to improve the efficiency of the PA is discussed quantitatively. Various parameters to be considered in designing are investigated in detail. The predistortion technology proposed is based on the lookup-table method using the input and output signal envelopes and can operate independently from the baseband block. By omitting adaptative predistortion for amplitude/phase modulation and integrating the main controlling functions on a single CMOS integrated-circuit chip, predistortion capability has been realized in a PA module. The PA module has power-added efficiency (PAE) of 48% at an output power of 27.5 dBm. This PAE is very high in comparison with that of the conventional PA module for N-CDMA. Index Terms--Amplitude-amplitude modulation (AM/AM), amplitude-phase modulation (AM/PM), code division multiple access (CDMA), module, power-added efficiency (PAE), power amplifier (PA), predistortion.

Aim: To investigate the effectiveness of public-access automated external defibrillators (AEDs) at Tokyo railroad stations.Methods: We analysed data from a population-based registry of out-of-hospital cardiac arrests in Tokyo, Japan (2014-2018). We identified patients aged ≥18 years who experienced bystander-witnessed cardiac arrest due to ventricular fibrillation of presumed cardiac origin at railroad stations. The primary outcome was survival at 1 month after cardiac arrest with favourable neurological outcomes (cerebral performance category 1-2).Results: Among 280 eligible patients who had bystander-witnessed cardiac arrest and received defibrillation at railroad stations, 245 patients (87.5%) received defibrillation using public-access AEDs and 35 patients (12.5%) received defibrillation administered by emergency medical services (EMS). Favourable neurological outcomes at 1 month after cardiac arrest were significantly more common in the group that received defibrillation using public-access AEDs (50.2% vs. 8.6%; adjusted odds ratio: 11.2, 95% confidence interval: 1.43-88.4) than in the group that received defibrillation by EMS. Over a 5-year period, favourable neurological outcomes at 1 month after cardiac arrest of 101.9 cases (95% confidence interval: 74.5-129.4) were calculated to be solely attributable to public-access AED use. The incremental cost-effectiveness ratio to gain one favourable neurological outcome obtained from public-access AEDs at railroad stations was lower than that obtained from nationwide deployment (48.5 vs. 2133.4 AED units).Conclusion: Deploying public-access AEDs at Tokyo railroad stations presented significant benefits and cost-effectiveness. Thus, it may be prudent to prioritise metropolitan railroad stations in public-access defibrillation programs. [ABSTRACT FROM AUTHOR]

A CMOS architecture for a floating linear resistor which exploits the square-law model of the MOS transistor is presented. The architecture is Programmable by dc control voltage and is easily modified such that it is threshold-voltage independent, allowing large signal handling and immunity to substrate noise. Design trade-offs and device size optimization are investigated. Second-order effects due to mobility degradation and channel length modulation are analyzed and a simple high frequency model for the resistor is developed. The architecture is fabricated in a 210 [mu]m p-well CMOS MOSIS process. The resistor occupies 210 [mu]m x 270 [mu]m consumes .4-4 mW with [+ or -]5 V supply and exhibits a signal (at 1% THD) to noise ratio of more than 100 dB over a 1-V range of the dc control voltage., A complementary metal oxide semiconductor (CMOS) implementation of a floating one-port linear resistor is presented. A discussion of the proposed architecture, which is based on the MOS transistor square-law model, includes an evaluation of second-order effects, design trade-offs and steps for device optimization. A model for the resistor's behavior at high frequency operation is provided together with results from a prototype fabricated in a two-micrometer CMOS technology are also given.

The formation of distinct supramolecular assemblies, including a metastable species, is revealed for a lipophilic guanosine (G) derivative in solution and in the solid state. Structurally different G-quartet-based assemblies are formed in chloroform depending on the nature of the cation, anion and the salt concentration, as characterized by circular dichroism and time course diffusion-ordered NMR spectroscopy data. Intriguingly, even the presence of potassium ions that stabilize G-quartets in chloroform was insufficient to exclusively retain such assemblies in the solid state, leading to the formation of mixed quartet and ribbon-like assemblies as revealed by fast magic-angle spinning (MAS) NMR spectroscopy. Distinct N−H⋅⋅⋅N and N−H⋅⋅⋅O intermolecular hydrogen bonding interactions drive quartet and ribbon-like self-assembly resulting in markedly different 2D 1H solid-state NMR spectra, thus facilitating a direct identification of mixed assemblies. A dissolution NMR experiment confirmed that the quartet and ribbon interconversion is reversible-further demonstrating the changes that occur in the self-assembly process of a lipophilic nucleoside upon a solid-state to solution-state transition and vice versa. A systematic study for complexation with different cations (K+, Sr2+) and anions (picrate, ethanoate and iodide) emphasizes that the existence of a stable solution or solid-state structure may not reflect the stability of the same supramolecular entity in another phase. [ABSTRACT FROM AUTHOR]

From a viewpoint of physical and chemical form estimation, ultra-trace analytical techniques of nuclear materials in environmental samples for safeguards have been investigated at Japan Atomic Energy Research Institute. This article deals with (1) an outline of the developed techniques for bulk and particle analyses of uranium and plutonium in the safeguards environmental samples; (2) current R&D on techniques relating to estimation of the physical and chemical form, such as SEM images and EDX spectra for fine particles of nuclear materials and fission track observation applicable to fissile materials; and (3) possible analytical methodologies, as future works, applicable to ultra-trace amounts of nuclear materials in environmental samples. [ABSTRACT FROM AUTHOR]

NMR analysis reveals that quartet assemblies formed by a guanosine building block in solution can transform into a mixture of quartet (Q) and ribbon (R) ‐ like assemblies after solvent evaporation. Our results demonstrate that the existence of a stable supramolecular structure in solution or in the solid state may not reflect its stability and integrity in another phase. More information can be found in the Full Paper by S. P. Brown et al. on page 2315 ff. [ABSTRACT FROM AUTHOR]

Invited for the cover of this issue is the group of Steven P. Brown at the University of Warwick and collaborators in Italy and the US. The image depicts the transformation (studied by NMR spectroscopy) between small molecule building blocks into unique assemblies during solid-solution interconversions. Read the full text of the article at . [ABSTRACT FROM AUTHOR]

Abstract: Crosslinking junctions of vulcanized natural rubber were analyzed by solid-state NMR spectroscopy equipped with a field-gradient high speed magic angle spinning probe. Resolution of 1H and 13C NMR spectra and correlations between 1H and 13C of the vulcanized natural rubber were investigated by one- and two-dimensional measurements, including inverse correlation measurements. The number of substitution of the carbon atom at the crosslinking junctions was determined by solid-state NMR spectroscopy. [Copyright &y& Elsevier]