Sensitivity of an anadically oxidized aluminium film on a surface acoustic wave sensor to humidity

The sensitivity, transient response and sensitivity mechanism of a surface acoustic wave humidity sensor using porous anodically oxidized aluminium (alumina) films as mechanical interfaces have been studied theoretically and experimentally. It is found that the sensitivity of alumina films of 1.0 μm thickness is -0.034 m/(s %RH) and is the same order as that of polyimide films. The transient response of alumina films to humidity is about one order faster than that of polyimide films. For the sensitivity mechanism, the phase-velocity change is attributed to the mechanical perturbation caused by the absorption of water molecules. The equivalent density change of alumina films between 0 and 100%RH is about 0.7%. In addition, the actual stiffness constants of alumina films are two orders less than those of bulk alumina.     

New phase-shifting technique for group-type unidirectional transducers used in surface-acoustic-wave filters

The letter reports a novel method of phase shifting useful in the group type of unidirectional transducers used for the design of low-loss SAW filters. This technique utilises the thin-film capacitance present between the newly described configuration of the feed-electrode layers as an essential element of the required phase shifter. The stray capacitance existing between the feed electrodes is used to advantage. The theoretical and experimental results of one of the filters fabricated are presented.     

Analysis and Design of a Dynamic Predistorter for WCDMA Handset Power Amplifiers

This paper presents a dynamic predistorter (PD), which linearizes the dynamic AM-AM and AM-PM of a wideband code division multiple access handset power amplifier (PA). The dynamic PD allows an adjacent channel leakage power ratio (ACPR) improvement of 15.7 dB, which is superior to conventional PDs that linearize static AM-AM and AM-PM. The dynamic PD was designed using an HBT generating nonlinearity, a short circuit at the baseband (les4 MHz), and a load circuit for the HBT at the RF fundamental band (ap1.95 GHz). Volterra-series analysis was performed to understand the mechanism of the dynamic PD. The analysis revealed that the short circuit at the baseband enabled the dynamic PD generating third-order intermodulation distortion (IMD3) with opposite phase to the fundamental tone (i.e., antiphase IMD3). The antiphase IMD3 allows dynamic gain compression, which linearizes the dynamic gain expansion of a PA with low quiescent current. The analysis also revealed that the IMD3 amplitude of the dynamic PD can be adjusted by load impedance at the RF fundamental band, which enables the gradient of dynamic AM-AM and AM-PM to be optimized to linearize the PA. The fabricated two-stage InGaP/GaAs HBT PA module with the dynamic PD exhibited an ACPR of -40 dBc and a power-added efficiency of 50% at an average output power of 26.8 dBm with a quiescent current of 20 mA     

New fabrication technique for single-phase unidirectional SAW filter (EMUDT) in UHF range

New fabrication techniques for single-phase unidirectional SAW filters (EMUDT) utilising the self-aligned angle-evaporation technique are described. The experimental results show a directivity of 10.0 dB/transducer at 483 MHz.     

High temperature stable GHz-range low-loss wide band transducersand filter using SiO2/LiNbO3, LiTaO3

GHz-range low-loss transducers and filters are required for communication systems, especially mobile telephone communication systems. Many types of low insertion-loss transducers and filters utilizing the high electromechanical coupling coefficient (K²) materials such as LiNbO₃ and LiTaO₃ have been developed. Unfortunately, these materials have large temperature coefficients of the frequency (TCF). In this paper, SAW substrates with high coupling coefficients and low propagation attenuations and small temperature coefficient of frequency in the GHz-range are theoretically and experimentally investigated. The experimental results show very low propagation loss of 0.02 dB/λ ₀ and larger K² than those of the substrates of LiNbO₃ and LiTaO₃ at the TCF of below -5 ppm/°C at 1~2 GHz-range. The low-loss filter results using internal reflection types of IDT show the insertion loss of about 2.9 dB at 1 GHz and 4.9 dB at 2 GHz under the TCF's of 0 and +20 ppm/°C. These materials are applicable for devices at GHz-range because SiO₂ thickness is very thin such as below 1 μm and the center frequency shift of the filter versus SiO₂ thickness is very small     

Non-protein energy overloading induces bacterial translocation during total parenteral nutrition in newborn rabbits

From a Maltese sample of the marine sponge Agelas oroides, five compounds: oroidin (1), 2-cyano-4,5-dibromopyrrole (2), 4,5-dibromopyrrole-2-carboxylic acid (3), 4,5-dibromopyrrole-2-carboxylic acid methyl ester (4), and 4 alpha-methyl-5 alpha-cholest-8-en-3 beta-ol (5) have been isolated. For compounds 1-5, completely assigned 1H- and 13C-NMR data are reported for the first time. For 2 a single crystal X-ray crystallographic analysis proved its structure unambiguously. The X-ray analysis of 2 indicated it to crystallise in an unexpected polar space group. Biological activity assessment of all isolates indicate 5 to have moderate antiplasmodial activity, as well as being cytotoxic, and 2 to be moderately cytotoxic towards several cancer cell lines.     

Morphologic changes in hepatocyte nuclei of streptozotocin (SZ)-induced diabetic mice

Morphological examinations were carried out on hepatocyte nuclei of streptozotocin (SZ)-induced diabetic mice. The area of hepatocyte nuclei in diabetic mice was about two times larger than that in control mice, and the incidence of hepatocytes with intranuclear inclusions was 3.4 +/- 0.2% in diabetic mice and 0% in control mice, respectively. Although the incidence of binuclear hepatocytes was not significantly different between diabetic (14.5 +/- 4.6%) and control mice (16.4 +/- 4.4%), the morphology of the nuclei of binuclear hepatocytes was apparently different between diabetic and control mice. Namely, the nuclei of binuclear hepatocytes of control mice were round and identical in ultrastructural appearance, and they did not differ from those of mononuclear diploid hepatocytes. On the other hand, the nuclei of binuclear hepatocytes of diabetic mice were not identical in distribution pattern of chromatin granules, and they frequently varied in size and showed irregular contours.     

Wilms' tumor suppressor gene (WT1) as a target gene of SRY function in a mouse ES cell line transfected with SRY

With the aim of identifying the gene(s) located downstream from SRY, we transfected an ES cell line with XX karyotype, TMA-18, with a Sry DNA construct and established cell lines, TS18-1 and TS18-2, where the transfected Sry was expressed in the functional linear mRNA form. Among the five potential SRY-target genes examined, i.e., MIS, SF1, P450arom, Sox9 and WT1, only the expression of WT1 was induced de novo by the unscheduled expression of Sry in the transfected cell lines. No clear indication of Sry-induced enhancement of Sox9 expression was obtained in the present series of experiments. Function of a yet unidentified gene(s) located on the Y chromosome might be needed for the up-regulation of Sox 9 expression which takes place during the development of male gonads. Quantitative RT-PCR analysis of the patterns of WT1 expression in developing fetal gonads revealed that although both male and female fetal gonads express WT1, male gonads invariably expressed WT1 mRNA at higher levels than female ones after the Sry expression. Immunohistochemical analysis of the male fetal gonads between 10.5 and 13.5 dpc demonstrated the presence of strong WT1 immunoreactivity in Sertoli cells of the primordial testes. Suggestions were made in the past indicating that both SF1 and WT1 proteins might be active in a common pathway upstream from Sry. Our results showed that WT1 is located downstream, rather than upstream from Sry and behaves independently from SF1. Analysis using an appropriate in vitro system will be essential to understand the molecular mechanisms of SRY action within cells.     

Neurological signs and frontal white matter lesions in vascular parkinsonism. A clinicopathologic study

BACKGROUND AND PURPOSE: The clinical characteristics and the pathological lesions of so-called vascular parkinsonism (VP) are still debatable. The purpose of this study was to define the core signs and symptoms and assess the cerebrovascular lesions in pathologically confirmed VP. METHODS: In the present study, VP was defined as the presence of parkinsonism and pathological evidence of cerebrovascular lesions but no depigmentation or Lewy bodies at the substantia nigra. We compared the clinical signs and symptoms of 24 VP patients with those of 30 age-matched patients with pathologically confirmed Parkinson's disease. We compared the brain pathology in VP patients with that in 22 age-matched patients with Binswanger's disease (BD) who had no parkinsonism according to clinical records. RESULTS: VP was characterized clinically by a short-stepped or frozen gait, lead-pipe rigidity, absence of resting tremor, and negative response to levodopa. Half or more of VP patients demonstrated pyramidal tract signs and pseudobulbar palsies. There was no significant difference in the extent of vascular lesions at the basal ganglia between patients with VP and with BD without parkinsonism. The extent of frontal white matter pallor tended to be less broad in VP than in BD without parkinsonism. In VP patients, the number of oligodendrocytes in the frontal white matter was significantly less than that in age-matched normal control subjects and significantly more than in those with BD. CONCLUSIONS: The core signs and symptoms of autopsy-proved VP differ from those of typical Parkinson's disease, and most VP patients had diffuse cerebral white matter lesions as well as basal ganglia lesions. VP might be related to frontal white matter lesions.