Small Loop Antenna System Design for Radio Direction Finding

In this literature, a low-cost small loop antenna is developed for radio direction finding. It consists of two coupled rectangular counter-wiring loop antennas. A signal-processing circuit is developed also for demodulated outputs. A single rectangular loop antenna is discussed first for illustrating the receiving characteristics and then the proposed two coupled rectangular counter-wiring loop antennas are designed for radio direction finding. Measurements give a large linear detecting range. It is ready for Omni-directional application using another two coupled loop antennas and can be used as a tracking control device.

A nuanced role of the small loop of hepatitis B virus small envelope protein in virion morphogenesis and secretion

Background The virion secretion mechanism of human hepatitis B virus (HBV) remains to be investigated. In our current study, we characterized a reverse transcriptase mutant, which changed from the YMDD motif to YMHA. We noted that this mutant YMHA secreted no virions in the medium. Because of the overlapping open reading frame (ORF) between the polymerase and the envelope genes, the lack of virion secretion is likely due to corresponding concurrent mutations in a small loop of the envelope protein (HBsAg, HBV surface antigen). In literature, small loop mutations are thought to affect virion secretion of hepatitis delta virus (HDV), but not HBV. Methods Here, we revisited the relationship between the small loop and virion secretion by site-directed mutagenesis and native agarose gel electrophoresis. Results A proline substitution at residue 196 or 198 in the small loop blocked both HBV genome-containing and genome-free virion secretion, but not the secretion of 22-nm HBsAg subviral particles. Surprisingly, a leucine substitution at residue 196 enhanced genome-containing virion secretion. It is also intriguing that a proline-197, sandwiched by residue 196 and 198, exhibited no apparent defect in secreted virions, with or without containing an HBV genome. By complementation assay, we demonstrated that the wild type small envelope protein alone is sufficient to rescue the virion secretion defect of a small loop mutant M198P. Conclusions The effect of the small loop mutation of HBV small envelope protein on virion secretion is position-dependent. It warrants further investigation how the small loop of HBsAg plays a subtle role in HBV morphogenesis and secretion of virions with or without containing an HBV genome.

High-resolution probe design for measuring the dielectric properties of human tissues

Background In order to use the microwave to measure the dielectric constant of the human body and improve the measurement resolution, a small near-field probe working at 915 MHz is designed in this paper. Method Based on the electric small loop antenna model loaded by the spiral resonator (SR), a small near-field probe was designed. The probe model is designed and optimized by the HFSS (high frequency structure simulator) software. The human tissues were tested by the manufactured probe and the relationship between the S11 parameters of the probe and the human tissues was analyzed. Results and conclusions A probe with small size was designed and fabricated, with the overall size of 10.0 mm × 12.0 mm × 0.8 mm. The probe has a good performance with a 30.7 dB return loss, a 20 MHz bandwidth at the resonance point, and a distance resolution of 10 mm. Due to the small size and good resolution of the probe, it can be used in the measurement of human tissues.

Structure of a C1/C4-oxidizing AA9 lytic polysaccharide monooxygenase from the thermophilic fungus Malbranchea cinnamomea

The thermophilic fungus Malbranchea cinnamomea contains a host of enzymes that enable its ability as an efficient degrader of plant biomass and that could be mined for industrial applications. This thermophilic fungus has been studied and found to encode eight lytic polysaccharide monooxygenases (LPMOs) from auxiliary activity family 9 (AA9), which collectively possess different substrate specificities for a range of plant cell-wall-related polysaccharides and oligosaccharides. To gain greater insight into the molecular determinants defining the different specificities, structural studies were pursued and the structure of McAA9F was determined. The enzyme contains the immunoglobulin-like fold typical of previously solved AA9 LPMO structures, but contains prominent differences in the loop regions found on the surface of the substrate-binding site. Most significantly, McAA9F has a broad substrate specificity, with activity on both crystalline and soluble polysaccharides. Moreover, it contains a small loop in a region where a large loop has been proposed to govern specificity towards oligosaccharides. The presence of the small loop leads to a considerably flatter and more open surface that is likely to enable the broad specificity of the enzyme. The enzyme contains a succinimide residue substitution, arising from intramolecular cyclization of Asp10, at a position where several homologous members contain an equivalent residue but cyclization has not previously been observed. This first structure of an AA9 LPMO from M. cinnamomea aids both the understanding of this family of enzymes and the exploration of the repertoire of industrially relevant lignocellulolytic enzymes from this fungus.

Comparison Between New Confidense HD Coloring Carto Mapping Module and New Rhythmia Mapping System for Scar Related Atrial Tachycardia Treatment.

Background. Scar-related atrial tachycardias (ATs) are very challenging and no comparative studies have been conducted between the up-to-date systems, namely the new Confidense HD coloring mapping module (HD) and the new Rhythmia (RM) mapping system. Objectives. Our study sought to compare both strategies in terms of: (1) diagnosis and immediate treatment success: (2) procedure parameters in AT presenting patients. Methods and Results. Overall, 38 patients (68±9 years old) were randomized (HD=20, RM=18). The AT mechanisms did not differ between the groups: macro/small loop reentrant mechanisms were more common in both groups (12/20 [60%] versus 10/18 [56%], P=0.9), with the remaining diagnosed as multiloop (5/20 [25%] versus 4/18 [22%]; p=0.9); focal (1/20 [5%] versus 2/18 [11%], P=0.9), and localized reentrant (2/20 [10%] versus 2/18 [11%]). The procedure parameters were as follows: tachycardia cycle length (275±30 vs. 280±50; p=0.7); number of activation maps per patient (2±1 vs 2±1; p=0.9); procedure time (138±90 vs. 139±90 min; p=0.98); X-ray time exposure (20±11 vs. 24±18 min; p=0.42); RF application time (39±36 vs. 25±28 min; p=0.21); and mean number of circuits per patient (1.8±1 vs. 1.6±0.9; 0.6). Acute success was obtained in 15/20 pts (75%) of the HD group and 14/18 (78%) of the RM group (p=0.9). The procedure failed in 2 patients with the HD coloring and they were converted to the RM group without success. No crossover was carried out in the RM group. Conclusions. This randomized study demonstrates that HD coloring and Rhythmia systems exhibit a similar efficacy in achieving acute AT termination.