A Tuning Circuit with Two Half-Wave Distributed Junctions for All-NbN SIS Mixers

A novel broadband tuning circuit composed of two low-current-density half-wave NbN/MgO/NbN tunnel junctions connected by a half-wave NbN/MgO/NbN microstrip line has been successfully tested in a quasi-optical mixer at frequencies above 700 GHz. The circuit had a designed center frequency of 870 GHz, was integrated in a center-fed twin-slot antenna, and was fed via a quarter-wave impedance transformer. Heterodyne measurments showed double-side-band receiver noise temperatures equivalent to 6-9 quanta from 675 to 810 GHz for a mixer with a current density of 6.7 kA/cm². The RF bandwidth was broader than that of a conventional mixer using a full-wave junction with the same current density.     

Identification of Tumor Suppressive Genes Regulated by miR-31-5p and miR-31-3p in Head and Neck Squamous Cell Carcinoma

We identified the microRNA (miRNA) expression signature of head and neck squamous cell carcinoma (HNSCC) tissues by RNA sequencing, in which 168 miRNAs were significantly upregulated, including both strands of the miR-31 duplex (miR-31-5p and miR-31-3p). The aims of this study were to identify networks of tumor suppressor genes regulated by miR-31-5p and miR-31-3p in HNSCC cells. Our functional assays showed that inhibition of miR-31-5p and miR-31-3p attenuated cancer cell malignant phenotypes (cell proliferation, migration, and invasion), suggesting that they had oncogenic potential in HNSCC cells. Our in silico analysis revealed 146 genes regulated by miR-31 in HNSCC cells. Among these targets, the low expression of seven genes (miR-31-5p targets: CACNB2 and IL34; miR-31-3p targets: CGNL1, CNTN3, GAS7, HOPX, and PBX1) was closely associated with poor prognosis in HNSCC. According to multivariate Cox regression analyses, the expression levels of five of those genes (CACNB2: p = 0.0189; IL34: p = 0.0425; CGNL1: p = 0.0014; CNTN3: p = 0.0304; and GAS7: p = 0.0412) were independent prognostic factors in patients with HNSCC. Our miRNA signature and miRNA-based approach will provide new insights into the molecular pathogenesis of HNSCC.     

Development of an epileptic seizure prediction algorithm using R–R intervals with self-attentive autoencoder

Epilepsy is a neurological disorder that may affect the autonomic nervous system (ANS) from 15 to 20 min before seizure onset, and disturbances of ANS affect R–R intervals (RRI) on an electrocardiogram (ECG). This study aims to develop a machine learning algorithm for predicting focal epileptic seizures by monitoring R–R interval (RRI) data in real time. The developed algorithm adopts a self-attentive autoencoder (SA-AE), which is a neural network for time-series data. The results of applying the developed seizure prediction algorithm to clinical data demonstrated that it functioned well in most patients; however, false positives (FPs) occurred in specific participants. In a future work, we will investigate the causes of FPs and optimize the developing seizure prediction algorithm to further improve performance using newly added clinical data.

     

Studies on analysis of terpene resin in imported chewing gums

We have developed an analytical method for terpene resins in chewing gum. The fraction including terpene resins was prepared by means of hexane extraction and two silica gel column chromatography treatments (hexane and ethyl acetate) from chewing gum. The terpene resin fraction was analyzed with LC/MS and IR. The terpene resins are mixtures of polymeric pinene and/or limonene, which have a monomer molecular weight of 136. The MS spectrum of the terpene resin peak on the LC/MS total ion chromatogram showed protonated molecular ion (M + H)+ peaks at intervals of m/z 136, characteristic of a complex mixture of polyterpenes. IR spectroscopy is a suitable technique to identify the terpene resin type, ie., pinene or limonene. When the method was applied to imported chewing gum sold in Japan, terpene resins were clearly detected.     

Using ontology to improve precision of terminology extraction from documents

In this paper, we proposed a new approach using ontology to improve precision of terminology extraction from documents. Firstly, a linguistic method was used to extract the terminological patterns from documents. Then, similarity measures within the framework of ontology were employed to rank the semantic dependency of the noun words in a pattern. Finally, the patterns at a predefined proportion according to their semantic dependencies were retained and regarded as terminologies. Experiments on Retuers-21578 corpus has shown that WordNet ontology, that we adopted for the task of extracting terminologies from English documents, can improve the precision of classical linguistic method on terminology extraction significantly.     

X-ray absorption fine structure combined with fluorescence spectrometry for monitoring trace amounts of lead adsorption in the environmental conditions

The local structure of trace amounts of lead in an adsorbent matrix that contains a high concentration of iron and magnesium (Mg6Fe2(OH)16(CO3) x 3H2O) was successfully monitored by means of X-ray absorption fine structure spectroscopy combined with fluorescence spectrometry. A eutectic mixture of PbCO3 and Pb(OH)2 coagulated when Pb2+ was adsorbed from a 1.0 ppm aqueous solution, and in contrast, the major species was ion-exchanged Pb2+ in the case of adsorption from a 100 ppb aqueous solution. The difference was ascribed to the balance between the precipitation equilibrium for coagulation and the rate of the ion exchange reaction with surface hydroxyl groups.     

Microcoaxial electrode for in vivo nitric oxide measurement

Nitric oxide (NO) is a gaseous mediator involved in various physiological phenomena, such as vasorelaxation and neurotransmission. Investigation of local cellular responses of NO production in vivo and in vitro requires a measurement method with a high spatial resolution. For selective NO measurement, we therefore developed a microcoaxial electrode whose tip diameter is less than 10 microm. Calibration using various concentrations of NO (0.1-1.0 microM) showed that the electrode has good linearity (r = 0.99) and its detection limit is 0.075 microM (S/N = 3). We verified the applicability of this electrode to in vivo and in vitro local measurement NO released from bovine aortic cultured endothelial cells (BAECs) stimulated by acetylcholine (ACh). After the addition of ACh, a transient increase in NO concentration was detected by the electrode. In the presence of NG-nitro-L-arginine methyl ester (L-NAME), a putative NO synthase inhibitor, NO release (peak NO concentration) from RAECs was significantly less than that in the absence of L-NAME (0.18 +/- 0.04 microM vs 0.47 +/- 0.13; P < 0.01). After removal of L-NAME, NO release partially recovered (0.39 +/- 0.10 microM). In conclusion, the microcoaxial electrode was successfully applied to direct and continuous NO measurement in biological systems.     

Effect of applied voltage frequency on swarming pulsive microdischarges in closed voids

The extinction of the partial discharge (PD) pulse has frequently been observed in an epoxy specimen with a closed void during voltage endurance tests using a CIGRE Method-II electrode. The individual discharge pulse becomes so small that the discharges cannot be detected by conventional pulse detection methods. Such discharges are known as “swarming pulsive microdischarges” (SPMD). In this paper, the SPMD characteristics are investigated by varying the frequency of the applied voltage from 0.1 to 240 Hz. As a result, the SPMD are found to occur less frequently as the frequency is lowered. To seek this cause, one-shot voltages were applied repeatedly at constant intervals. By varying the interval from 0.02 to 100 s, the PD off an electrically aged specimen was measured. It was revealed that the discharge magnitude increases as the interval becomes longer. The onset of SPMD was found to depend on the preceding discharge. The results explain the reason why swarming is harder to occur at lower frequency with a longer discharge interval. Hence, in the conventional pulse detection, it is useful to employ the very low frequency for diagnosis of machine insulation containing enclosed voids.     

Synthetic potential of molluscan sulfatases for the library synthesis of regioselectively O-sulfonated D-galacto-sugars

The substrate specificities of three molluscan sulfatases (E.C. 3.1.6.1; snail, abalone, and limpet origins) were investigated with assorted p-nitrophenyl (pNP) di-O-sulfonated beta-D-galactopyranosides and beta-lactosides [3,6-SO(3) Gal (1), 3',6'-SO(3) Lac (2), 4, 6SO(3) Gal (3), 2,6-SO(3) Gal (4), 3,4-SO(3) Gal (5), and 3,6-SO(3) GalNAc (6); Ac, acetyl; Gal, galactose; Lac, lactose] together with mono-O-sulfonated beta-D-galactopyranoside [pNP 3SO(3)-Gal (7)] and tri-O-sulfonated alpha-D-galactopyranoside [2,3,6-SO(3)-alpha-Gal (11)]. Some notable differences between the substrate specificity of the three sulfatases were disclosed; snail sulfatase hydrolyzed the 3O- and 2O-sulfo groups of 1 and 4, respectively, to afford 6SO(3) Gal (9) in high yields, while the abalone enzyme did not act on 4. Only the limpet enzyme could cleave the 3O-sulfo groups of 7 to give pNP beta-galactoside. In contrast, every enzyme could utilize 11 as a good substrate to afford a mixture of 6SO(3)-alpha-Gal (13) and 2,6-SO(3) alpha-Gal (12). None of the enzymes could cleave the O-sulfo groups of 5 and 6, which indicates that a primary 6O-sulfo group tends to promote the enzymatic hydrolysis of O-sulfo groups at the secondary positions.     

Identifying rotation and oscillation in surface tension measurement using an oscillating droplet method

We proposed a new approach to identify the frequencies of droplet rotation and m=±2 oscillation that degrade the accuracy of surface tension measurement by an oscillating droplet method. Frequencies of droplet rotation and m=±2 oscillation can be identified by a phase unwrapping analysis of time dependence of the deflection angle for the maximum diameter of the droplet image observed from above. The present method was validated, using test data with given frequencies. © 2008 Wiley Periodicals, Inc. Heat Trans Asian Res, 37(7): 421–430, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20214