Dual-Band Monopole MIMO Antenna Array for UAV Communication Systems.

This study proposes a compact, low-profile, four-port dual-band monopole multiple-input-multiple-output (MIMO) antenna array for unmanned aerial vehicle (UAV) communication systems. Each monopole antenna of the array features a modified T-shaped radiator configuration and is printed on a Rogers RT5880 substrate with compact dimensions of 134.96 mm × 134.96 mm × 0.8 mm. A four-element square MIMO configuration with sequential 0°, 90°, 180°, and 270° rotations was integrated smoothly into the UAV body. A prototype of the MIMO array was fabricated and experimentally evaluated, with measured results showing a close correlation to simulated results. The proposed dual-band monopole antenna demonstrated one of the widest impedance bandwidths of 46.15% at 2.4 GHz (2.04 to 3.25 GHz) IEEE 802.11b and 31.85% at 5.8 GHz (5.37 to 7.38 GHz) IEEE 802.11a on a thin 0.0064 λo substrate while achieving high transmission efficiency. The isolation of the proposed four-port MIMO design was measured at 23 dB at 2.4 GHz and 19 dB at 5.8 GHz. The MIMO array's total efficiency of each monopole antenna was measured at 96% at 2.4 GHz and 89% at 5.8 GHz. The design has measured diversity parameters such as an ECC below 0.01 and a DG of approximately 10. Based on these results, the proposed design suits the UAV communication system.

Exploring Bemisia tabaci Middle East-Asia Minor I and Mediterranean Cryptic Species Relationship with Cowpea Mild Mottle Virus and Their Dynamics in Soybean Fields.

Cowpea mild mottle virus (CPMMV, genus Carlavirus, family Betaflexividae) is an economically important virus infecting soybeans in Brazil, where it was initially identified in 1983. CPMMV is transmitted by the whitefly, Bemisia tabaci, and occasionally by seeds. Over the last three decades, the most invasive B. tabaci Middle East-Asia Minor 1 (MEAM1), and lately the Mediterranean (MED) cryptic species, have replaced the indigenous species in Brazil, with MEAM1 being predominant. In this study, we investigated the transmission properties of CPMMV by MEAM1 and MED, and their distribution in major soybean-growing areas in São Paulo State. Our results from transmission assays with a single insect revealed that MED is a more efficient vector compared to MEAM1, transmitting the virus within a two-minute inoculation access period. B. tabaci MEAM1 is still the predominant whitefly species in São Paulo State, but MED was also identified in different places, mainly in mixed infestations with MEAM1. Some areas transitioned to a predominance of MED over the three years, while others, where MED had previously been detected, showed a reduction in the insects during the same period. Understanding the transmission dynamics of CPMMV and the distribution of its vectors is crucial for implementing effective management strategies to control the virus spread and protect soybean crops. Further research into the mechanisms driving the shifts in whitefly species dominance and CPMMV distribution will be essential for sustaining soybean production in Brazil.

Genetic diversity in vector populations influences the transmission efficiency of an important plant virus.

The transmission efficiency of aphid-vectored plant viruses can differ between aphid populations. Intra-species diversity (genetic variation, endosymbionts) is a key determinant of aphid phenotype; however, the extent to which intra-species diversity contributes towards variation in virus transmission efficiency is unclear. Here, we use multiple populations of two key aphid species that vector barley yellow dwarf virus (BYDV) strain PAV (BYDV-PAV), the grain aphid (Sitobion avenae) and the bird cherry-oat aphid (Rhopalosiphum padi), and examine how diversity in vector populations influences virus transmission efficiency. We use Illumina sequencing to characterize genetic and endosymbiont variation in multiple Si. avenae and Rh. padi populations and conduct BYDV-PAV transmission experiments to identify links between intra-species diversity in the vector and virus transmission efficiency. We observe limited variation in the transmission efficiency of Si. avenae, with transmission efficiency consistently low for this species. However, for Rh. padi, we observe a range of transmission efficiencies and show that BYDV transmission efficiency is influenced by genetic diversity within the vector, identifying 542 single nucleotide polymorphisms that potentially contribute towards variable transmission efficiency in Rh. padi. Our results represent an important advancement in our understanding of the relationship between genetic diversity, vector-virus interactions, and virus transmission efficiency.

Simulation study of a new racetrack FAIMS analyzer to achieve both high-resolution and high-sensitivity.

A new racetrack field-asymmetric waveform ion mobility spectrometry (r-FAIMS) analyzer was developed in this study by combining the existing planar FAIMS (p-FAIMS) and cylindrical FAIMS (c-FAIMS). The ion inlet and outlet regions of r-FAIMS were consisted of a half of c-FAIMS, respectively, and these c-FAIMS were further connected by two p-FAIMS to form a racetrack shaped FAIMS. With such FAIMS working electrode configuration, the ions entering the r-FAIMS can be focused and separated in the first c-FAIMS section, be further separated in the p-FAIMS section with high-resolution, be focused and separated again in the final c-FAIMS section and eventually enter the mass spectrometer or other analyzers for analysis. Detailed simulation by using SIMION software with the default FAIMS user program showed that the ion focusing effect in the first c-FAIMS section ensures the ions entering the following p-FAIMS section as a compact ion packet. This effectively decreases the ion loss caused by Coulomb repulsion and thermal diffusion in p-FAIMS section as compared to the ions being introduced into the p-FAIMS gap randomly in the conventional design. As a result, the ion transmission efficiency of r-FAIMS is at least 3.3-fold higher than the single p-FAIMS under the operating conditions used in this study. The ion trajectory simulation results also showed that the resolving power of r-FAIMS is about the sum of the resolving powers for its c-FAIMS and p-FAIMS sections. The resolving power of r-FAIMS is at least 3.6-fold higher than the single c-FAIMS under the operation conditions used in this study. Therefore, the r-FAIMS can realize both high-resolution and high-sensitive ion mobility separation.

Per- and polyfluoroalkyl substances (PFAS) exposure in plasma and their blood-brain barrier transmission efficiency-A pilot study.

Per- and polyfluoroalkyl substances (PFAS) have been shown to penetrate the blood-brain barrier (BBB) and accumulate in human brain. The BBB transmission and accumulation efficiency of PFAS, as well as the potential health risks from human co-exposure to legacy and emerging PFAS due to differences in transport efficiency, need to be further elucidated. In the present pilot study, 23 plasma samples from glioma patients were analyzed for 17 PFAS. The concentrations of PFAS in six paired brain tissue and plasma samples were used to calculate the BBB transmission efficiency of PFAS (RPFAS). This RPFAS analysis was conducted with utmost care and consideration amid the limited availability of valuable paired samples. The results indicated that low molecular weight PFAS, including short-chain and emerging PFAS, may have a greater potential for accumulation in brain tissue than long-chain PFAS. As an alternative to perfluorooctane sulfonic acid (PFOS), 6:2 chlorinated polyfluorinated ether sulfonate (6:2 Cl-PFESA) exhibited brain accumulation potential similar to that of PFOS, suggesting it may not be a suitable substitute concerning health risk in brain. The BBB transmission efficiencies of perfluorooctanoic acid, PFOS, and 6:2 Cl-PFESA showed similar trends with age, which may be an important factor influencing the entry of exogenous compounds into the brain. A favorable link between perfluorooctane sulfonamide (FOSA) and the development and/or progression of glioma may be implicated by a strong positive correlation (r2 = 0.94; p < 0.01) between RFOSA and Ki-67 (a molecular marker of glioma). However, a causal relationship between RFOSA and glioma incidence were not established in the present study. The present pilot study conducted the first examination of BBB transmission efficiency of PFAS from plasma to brain tissue and highlighted the importance of reducing and/or controlling exposure to PFAS.

Transmission efficiency of one tooth difference sine tooth profile planetary reducer.

The structural size of space exploration and unmanned aerial vehicle manipulator is required to be as small as possible, and the weight must be as light as possible. However, the existing reducers have difficulties in achieving lightweight robot joint drive systems. For it, this paper proposes a single tooth difference continuous sine tooth profile K-H-V type planetary reducer in which pin type equi-speed output mechanism is used. Concerning the reducer, its structural composition and meshing characteristics are analyzed. Based on the findings, the meshing pair's force, the friction coefficient, and the meshing efficiency are investigated. The force and bearing efficiency of the planetary gear are studied, and the efficiency of the equi-speed output mechanism in addition to the total efficiency of the reducer are determined. Moreover, the efficiency of the reducer prototype is measured and compared to the calculated efficiencies. The results show that the gear modulus, the input speed, the surface roughness, and the lubricating oil viscosity have a significant effect on the meshing efficiency. Furthermore, the efficiency of the eccentric bearings is significantly lower than that of the non-eccentric bearings. Therefore, it can be increased by tuning the pressure angle, the tooth number of planetary gear, the tooth height, and the distribution circle radius of the pinhole. In addition, the power loss of the output mechanism has the greatest effect on transmission efficiency. Reducing the center distance, the inner diameter of the rotating arm bearing, and the tooth number of planetary gear, as well as increasing the outer diameter of the pin shaft can reduce the power loss of the output mechanism. The experimental efficiency of the reducer prototype is 82.47%, its computational efficiency is 83.72%, and its error is 1.25%, verifying the correctness of the efficiency calculation method.

Design of a mid-field wireless power transmission system for deep-tissue implants.

BACKGROUND: Implantable medical devices are being valued as one of the developments of wireless biomedical technology. OBJECTIVE: This paper presents a mid-field wireless power transmission (WPT) system, which is designed for implantable applications and operates at the 2.40-2.48 GHz band of Industrial, Scientific, and Medical (ISM). METHODS: A new compact transmitter structure is proposed, and a small 4-C planar ring antenna is designed as the receiving element. A measurement setup is fulfilled on porcine tissues to verify the power transmission system. RESULTS: The experimental results show that the operating bandwidth is 2.2-2.62 GHz and the transmission coefficient can reach -26.32 dB at a distance of 50 mm. The effects of tissue differences, placement depth, and different transmission distances were also measured. The displacement and deflection tolerances between the transmitter and the implant receiver also have good performance. In the safety standard of specific absorption rate, for the 1 W output power from the mid-field transmitter, the receiving power of the implantable antenna at the mid-field distance can reach 79.6 mW. CONCLUSION: With measurements of different implantation and transmission distance on pork, the mid-field power transmission efficiency is proven and shows the high performance of the system.

The Design of a Circularly Polarized Antenna Array with Flat-Top Beam for an Electronic Toll Collection System.

Electronic toll collection (ETC), known as a non-stop toll collection system which can automatically realize payment by setting the identification antenna at the entrance, is always suffering from information exchange interruption caused by beam switching. A circularly polarized sector beam antenna array operating at 5.8 GHz with flat-top coverage is proposed, based on the weighted constrained method of the maximum power transmission efficiency (WCMMPTE). By setting the test receiving antennas at the specific angles of the ETC antenna array to be designed, constraints on the received power are introduced to control the radiation pattern and obtain the optimized distribution of excitations for antenna elements. A 1-to-16 feeding network, based on the microstrip transmission line theory is designed to feed a 4 × 4 antenna array. Simulation results show that the half-power beamwidth covers an angular range of -30° to 30° while the axial ratio is below 3dB, which meets the ETC requirements. Furthermore, the gain fluctuation among the needed range of -30° to 30° is lower than 0.7 dB, which is suitable for the ETC system to achieve a stable signal strength and uninterrupted communication.

Evaluating temporal bone column density for optimized bone conduction implant placement.

Introduction: An optimal placement of bone conduction implants can provide more efficient mechanical transmission to the cochlea if placed in regions with greater bone column density. The aim of this study was to test this hypothesis and to determine the clinical potential of preoperative bone column density assessment for optimal implant placement. Methods: Five complete cadaver heads were scanned with quantitative computed tomography imaging to create topographic maps of bone density based on the column density index (CODI). Laser Doppler vibrometry was used to measure cochlear promontory acceleration under bone conduction stimulation in different locations on the temporal bone, using a bone-anchored hearing aid transducer at frequencies ranging from 355 Hz to 10 kHz. Results: We found a statistically significant association between CODI levels and the accelerance of the cochlear promontory throughout the frequency spectrum, with an average increase of 0.6 dB per unit of CODI. The distance between the transducer and the cochlear promontory had no statistically significant effect on the overall spectrum. Discussion: We highlight the importance of bone column density in relation to the mechanical transmission efficiency of bone conduction implants. It may be worthwhile to consider column density in preoperative planning in clinical practice.

A Printed Dipole Array with Bidirectional Endfire Radiation for Tunnel Communication.

Tunnel communication always suffers from path loss and multipath effects caused by surrounding walls. Meanwhile, the traditional leaky coaxial cables are expensive to deploy, inconvenient to operate, and difficult to maintain, leading to many problems in practical use. To solve the abovementioned problems, a low-profile printed dipole array operating at 3.5 GHz with bidirectional endfire radiation is designed based on the method of maximum power transmission efficiency (MMPTE). By setting two virtual test receiving dipoles at the two opposite endfire directions and then maximizing the power transmission efficiency between the printed dipole array to be designed and the test receiving antennas, the optimal amplitudes and phases for the array elements are obtained. Based on the optimal distributions of excitations, the simulation results show that the proposed eight-element printed dipole array can simultaneously generate two mirrored endfire beams towards opposite directions. Furthermore, the corresponding normalized cross-polarization levels are lower than -22.3 dBi both in the azimuth and elevation planes. The peak endfire gain is 10.7 dBi with maintenance of higher than 10 dBi from 3.23 GHz to 3.66 GHz, which is suitable for tunnel communication.

Fiber-to-Chip Three-Dimensional Silicon-on-Insulator Edge Couplers with High Efficiency and Tolerance.

The edge coupler is an indispensable optical device for connecting an external fiber and on-chip waveguide. The coupling efficiency of the edge coupler affects the effective integration of optical circuits. In this study, three-dimensional (3D) edge couplers with high efficiency and tolerance are proposed. The high coupling efficiency of the 3D edge couplers is verified by theoretical calculations. Three couplers are fabricated on a thick-silicon platform via 3D grayscale lithography. At the 1550 nm band, the fiber-to-chip experimental data show that the maximum coupling efficiencies of the three edge couplers are 0.70 dB and 1.34 dB, 0.80 dB and 1.60 dB, and 1.00 dB and 1.14 dB for the TE and TM modes, respectively. At the 1550 nm band, misalignment tolerances measurement data reveal 0.8 dB/0.9 dB tolerance of ±5 µm in the horizontal direction, and 1.7 dB/1.0 dB tolerance of ±2 µm in the vertical direction for TE/TM mode. This study provides a new idea for the design of 3D edge couplers and demonstrates significant superiority in research and industrial applications.

Estimating the Impact of Consecutive Blood Meals on Vector Competence of Aedes albopictus for Chikungunya Virus.

The continuous expansion of Aedes albopictus in Europe and the increases in autochthonous arboviruses transmissions in the region urge a better understanding of the virus transmission dynamic. Recent work described enhanced chikungunya virus (CHIKV) dissemination in Aedes aegypti mosquitoes exposed to a virus-free blood meal three days after their infection with CHIKV. Our study investigated the impact of a second blood meal on the vector competence of Ae. albopictus from southern Switzerland infected with CHIKV. Seven-day-old Ae. albopictus females were exposed to CHIKV-spiked blood and incubated at constant (27 °C) and fluctuating (14-28 °C) temperatures. Four days post-infection (dpi), some of these females were re-fed with a non-infectious blood meal. Virus infectivity, dissemination, transmission rate, and efficiency were investigated at seven and ten dpi. No enhanced dissemination rate was observed among females fed a second time; however, re-fed females have shown higher transmission efficiency than those fed only once after seven days post-infection and incubated under a fluctuating temperature regime. Vector competence for CHIKV was confirmed in Ae. albopictus from southern Switzerland. We did not observe an increase in dissemination rates among mosquitoes fed a second time (second blood meal), regardless of the temperature regime.

Clinical isolates of hepatitis B virus genotype C have higher in vitro transmission efficiency than genotype B isolates.

Serum samples were collected from 54 hepatitis B e antigen (HBeAg)-positive Chinese patients infected with hepatitis B virus (HBV) subgenotype B2 or C2. They were compared for transmission efficiency using same volume of samples or infectivity using same genome copy number. Adding polyethylene glycol (PEG) during inoculation did not increase infectivity of fresh samples but markedly increased infectivity following prolonged sample storage. Differentiated HepaRG cells infected without PEG produced more hepatitis B surface antigen (HBsAg) and higher HBsAg/HBeAg ratio than sodium taurocholate cotransporting polypeptide (NTCP)-reconstituted HepG2 cells infected with PEG. They better supported replication of core promoter mutant in contrast to wild-type (WT) virus by HepG2/NTCP cells. Overall, subgenotype C2 samples had higher viral load than B2 samples, and in general produced more HBeAg, HBsAg, and replicative DNA following same-volume inoculation. Precore mutant was more prevalent in subgenotype B2 and had reduced transmission efficiency. When same genome copy number of viral particles was inoculated, viral signals were not necessarily higher for three WT C2 isolates than four WT B2 isolates. Using viral particles generated from cloned HBV genome, three WT C2 isolates showed slightly reduced infectivity than three B2 isolates. In conclusion, subgenotype C2 serum samples had higher transmission efficiency than B2 isolates in association with higher viral load and lower prevalence of precore mutant, but not necessarily higher infectivity. PEG-independent infection by HBV viremic serum samples is probably attributed to a labile host factor.

Processing objects of perceptual expertise: Differential interhemispheric transmission efficiency but similar transmission direction advantages.

Faces and Chinese characters are both objects of perceptual expertise. In this study, we investigated the characteristics of interhemispheric transmission times (IHTTs) in both transmission direction and transmission efficiency during the processing of objects of perceptual expertise. A total of 112 participants engaged in a divided visual field paradigm for faces, Chinese characters, and houses in both upright and inverted orientations. The N170 amplitudes elicited by the objects of perceptual expertise (faces and Chinese characters) involved in this study were larger than those elicited by the non-perceptual expertise objects (houses). We used the latencies of the N170 component of the event-related potential (ERP) recorded in the left and right hemispheres to calculate the IHTTs. For all objects, the N170-related IHTTs from the right to the left hemispheres were shorter than those in the opposite direction. Essentially, the N170-related IHTTs for faces were shorter, that is, more efficient than those for Chinese characters and houses. This result indicates that the IHTTs during perceptual expertise and non-perceptual expertise object processing share a common transmission direction advantage, but transmission efficiency is face-specific.

The effects of the E3 ubiquitin-protein ligase UBR7 of Frankliniella occidentalis on the ability of insects to acquire and transmit TSWV.

The interactions between plant viruses and insect vectors are very complex. In recent years, RNA sequencing data have been used to elucidate critical genes of Tomato spotted wilt ortho-tospovirus (TSWV) and Frankliniella occidentalis (F. occidentalis). However, very little is known about the essential genes involved in thrips acquisition and transmission of TSWV. Based on transcriptome data of F. occidentalis infected with TSWV, we verified the complete sequence of the E3 ubiquitin-protein ligase UBR7 gene (UBR7), which is closely related to virus transmission. Additionally, we found that UBR7 belongs to the E3 ubiquitin-protein ligase family that is highly expressed in adulthood in F. occidentalis. UBR7 could interfere with virus replication and thus affect the transmission efficiency of F. occidentalis. With low URB7 expression, TSWV transmission efficiency decreased, while TSWV acquisition efficiency was unaffected. Moreover, the direct interaction between UBR7 and the nucleocapsid (N) protein of TSWV was investigated through surface plasmon resonance and GST pull-down. In conclusion, we found that UBR7 is a crucial protein for TSWV transmission by F. occidentalis, as it directly interacts with TSWV N. This study provides a new direction for developing green pesticides targeting E3 ubiquitin to control TSWV and F. occidentalis.

Vector Competence for Zika Virus Changes Depending on the Aedes aegypti's Region of Origin in Manaus: A Study of an Endemic Brazilian Amazonian City.

Zika virus (ZIKV) is transmitted to humans by the infectious bite of mosquitoes such as Aedes aegypti. In a city, the population control of mosquitoes is carried out according to alerts generated by different districts via the analysis of the mosquito index. However, we do not know whether, besides mosquito abundance, the susceptibility of mosquitoes could also diverge among districts and thus impact the dissemination and transmission of arboviruses. After a viremic blood meal, the virus must infect the midgut, disseminate to tissues, and reach the salivary gland to be transmitted to a vertebrate host. This study evaluated the patterns of ZIKV infection in the Ae. aegypti field populations of a city. The disseminated infection rate, viral transmission rate, and transmission efficiency were measured using quantitative PCR at 14 days post-infection. The results showed that all Ae. aegypti populations had individuals susceptible to ZIKV infection and able to transmit the virus. The infection parameters showed that the geographical area of origin of the Ae. aegypti influences its vector competence for ZIKV transmission.

Regulated Thermal Boundary Conductance between Copper and Diamond through Nanoscale Interfacial Rough Structures.

Interfacial structure optimization is important to enhance the thermal boundary conductance (TBC) as well as the overall performance of thermal conductive composites. In this work, the effect of interfacial roughness on the TBC between copper and diamond is investigated with molecular dynamics (MD) simulations and time-domain thermoreflectance (TDTR) experiments. It is found from MD simulations that the thermal transport efficiency across a rough interface is higher, and the TBC can be improved 5.5 times to 133 MW/m2·K compared with that of the flat interface. Also, the TBC is only dominated by the actual contact area at the interface for larger roughness cases; thus, we conclude that the phonon scattering probability increases with the increase of roughness and becomes stable gradually. Finally, the TBC of the copper/diamond interface with different roughness is characterized by TDTR experiments, and the results also confirm the trend of MD simulations. This study demonstrates the feasibility of the roughness modification for interfacial thermal management from both theoretical analysis and experimental measurements and provides a new idea for enhancing the thermal conductivity of composites.

Proteomic and Transcriptomic Analysis for Identification of Endosymbiotic Bacteria Associated with BYDV Transmission Efficiency by Sitobion miscanthi.

Sitobion miscanthi, an important viral vector of barley yellow dwarf virus (BYDV), is also symbiotically associated with endosymbionts, but little is known about the interactions between endosymbionts, aphid and BYDV. Therefore, two aphids' geographic populations, differing in their BYDV transmission efficiency, after characterizing their endosymbionts, were treated with antibiotics to investigate how changes in the composition of their endosymbiont population affected BYDV transmission efficiency. After antibiotic treatment, Rickettsia was eliminated from two geographic populations. BYDV transmission efficiency by STY geographic population dropped significantly, by -44.2% with ampicillin and -25.01% with rifampicin, but HDZ geographic population decreased by only 14.19% with ampicillin and 23.88% with rifampicin. Transcriptomic analysis showed that the number of DEGs related to the immune system, carbohydrate metabolism and lipid metabolism did increase in the STY rifampicin treatment, while replication and repair, glycan biosynthesis and metabolism increased in the STY ampicillin treatment. Proteomic analysis showed that the abundance of symbionin symL, nascent polypeptide-associated complex subunit alpha and proteasome differed significantly between the two geographic populations. We found that the endosymbionts can mediate vector viral transmission. They should therefore be included in investigations into aphid-virus interactions and plant disease epidemiology. Our findings should also help with the development of strategies to prevent virus transmission.

Increased myelination plays a central role in white matter neuroplasticity.

White matter (WM) neuroplasticity in the human brain has been tracked non-invasively using advanced magnetic resonance imaging techniques, with increasing evidence for improved axonal transmission efficiency as a central mechanism. The current study is the culmination of a series of studies, which characterized the structure-function relationship of WM transmission efficiency in the cortico-spinal tract (CST) during motor learning. Here, we test the hypothesis that increased transmission efficiency is linked directly to increased myelination using myelin water imaging (MWI). MWI was used to evaluate neuroplasticity-related improvements in the CST. The MWI findings were then compared to diffusion tensor imaging (DTI) results, with the secondary hypothesis that radial diffusivity (RD) would have a stronger relationship than axial diffusivity (AD) if the changes were due to increased myelination. Both MWI and RD data showed the predicted pattern of significant results, strongly supporting that increased myelination plays a central role in WM neuroplasticity.

Structure Design of Quadrilateral Overlapped Wireless Power Transmission Coupling Coil.

The application of wireless power transmission technology is becoming more and more extensive. However, in practical applications, the problem of reducing the energy transmission efficiency caused by the offset of the coupling coil needs to be solved urgently. Changing the coil structure is a widely adopted method to deal with this problem. Based on the characteristics of the existing magnetic coupling resonant wireless power transmission system and the principle of the anti-offset coil, this paper innovatively designs a new type of quadrilateral overlapping wireless power transfer coupling coil, which has a strong anti-offset capability. The new type of coil model was built in the simulation and experiment, and the relevant parameters were measured. Experimental results verify that the proposed coil structure has an excellent anti-offset capability.