Search

In recent years, new payment methods have emerged, aimed at improving convenience for users. Cryptocurrencies, in principle, are no different. In this study, we seek to analyze the general population's attitudes towards the adoption of cryptocurrencies as a payment method. To achieve this, we have developed a descriptive survey that targets both current cryptocurrency users and non-users, recognizing that differences in perception may exist. Additionally, we have conducted a sentiment analysis of open-ended questions to understand respondents' views on the future of the cryptocurrency market and its potential as a payment tool, utilizing different lexicons in the English language. Our findings indicate that most cryptocurrency users prefer to invest in these digital assets, often choosing coins based on their popularity rather than other intrinsic features. E-commerce payments are the most attractive activity, followed by international transactions when using cryptocurrencies as a payment method. However, high volatility and a lack of ease of use are the most common difficulties reported by users. Our study also highlights the importance of regulation in a time when users are increasingly demanding higher levels of oversight, in contrast to the past. While users are concerned about the instability and volatility of cryptocurrencies, they also value the anonymity these transactions offer. Our analysis showcases an innovative approach to analyzing interviews and qualitative questionnaires that can be applied in other research fields.

Abstract The authors proposed an ultrawideband (UWB) dual‐polarised tightly coupled dipole array (TCDA). A split X‐shaped resistive frequency selective surface (FSS) is utilised, which can get more admirable impedance matching. The proposed antenna can achieve active voltage standing wave ratio (VSWR) below 2.9 when scanning up to ±75° and ±60° in the E and H planes from 2 to 18 GHz, respectively. Furthermore, two rectangular patches served as directors are designed, which can provide stronger forward radiation to reduce the loss of resistive FSS for radiation efficiency. As a result, the average radiation efficiency is above 84% and the lowest radiation efficiency is 70%. Moreover, the overall antenna profile is 15 mm (0.1λ at the largest working wavelength). To validate the design method, a 16 × 16 array prototype is fabricated and measured. Good agreement is achieved between the simulations and measurements.

Background: Sodium–glucose cotransporter-2 (SGLT2) inhibitors have proven to be effective in improving glycemic control in patients with type 2 diabetes mellitus (T2DM). However, the risk of diabetic ketoacidosis (DKA) in patients remains unclear. The purpose of this study is to conduct this systematic review and network meta-analysis for the risk of DKA of SGLT2 inhibitors in patients with T2DM.Methods: We searched for randomized controlled trials (RCTs) concerning SGLT2 inhibitors in patients with T2DM in PubMed, EMBASE (Ovid SP), Cochrane Central Register of Controlled Trials (Ovid SP), and ClinicalTrials.gov from inception to January 2022. The primary outcomes were the risk of DKA. We assessed the sparse network with a fixed-effect model and consistency model in a frequentist framework with a graph-theoretical method by the netmeta package in R. We assessed the evidence quality of evidence of outcomes according to the Grading of Recommendations Assessment, Development, and Evaluation (GRADE).Results: In total, 36 studies involving 52,264 patients were included. The network showed that there was no significant difference observed among SGLT2 inhibitors, other active antidiabetic drugs, and placebo in the risk of DKA. There was no significant difference in the DKA risk between different doses of SGLT2 inhibitors. The certainty of the evidence ranged from very low to moderate. The probabilities of rankings and P-score showed that compared to placebo, SGLT2 inhibitors might increase the risk of DKA (P-score = 0.5298). Canagliflozin might have a higher DKA risk than other SGLT2 inhibitors (P-score = 0.7388).Conclusion: Neither SGLT2 inhibitors nor other active antidiabetic drugs were associated with an increased risk of DKA compared to placebo, and the risk of DKA with SGLT2 inhibitors was not found to be dose-dependent. In addition, the use of canagliflozin was less advisable than other SGLT2 inhibitors according to the rankings and P-score.Systematic Review Registration:https://www.crd.york.ac.uk/prospero/, identifier PROSPERO, CRD42021297081.

Understanding the link between biodiversity and ecosystem functioning is imperative for ecosystem-based management. The role of multitrophic diversity in sustaining multifunctionality remains unclear, especially in highly diverse aquatic ecosystems. We performed a species-addition experiment consisting of one, two, three, and five species in simulated multitrophic ecosystems to evaluate biodiversity and ecosystem functioning relationships within and across trophic levels. Our results showed that there are positive species richness–productivity relationships within and across trophic levels. We found significant negative correlations between species richness and the cumulative variation of total phosphorus, and between species richness and ecosystem multifunctionality across trophic levels. Also, we found that the relationships between ecosystem multifunctionality and species richness within and across the trophic levels are mediated by a combination of environmental factors, including water temperature, dissolved oxygen, pH, irradiance, and time, rather than by species richness. Our results imply that species richness–ecosystem functioning relationships vary for different ecological functions; the individual ecosystem functions selected and the way multifunctionality calculated are critical when examining links between biodiversity and ecosystem multifunctionality. Our study highlights that multitrophic richness, such as for consumers, is crucial for driving ecosystem multifunctionality. Furthermore, our study implies that management practices for restoring the diversity of aquatic macrophytes in wetlands should consider not only macrophyte richness but also different functional groups and life-forms.

A low-profile wide-scanning conformal phased array (CPA), with cavity-backed stacked patch elements, is presented in this paper. To reduce the array profile, a partially dielectric-filled cavity is employed in each element, and to enhance its scanning performance, the cavity walls are deliberately modified. Finally, the designed element operates in a frequency band of 1.45∼1.75 GHz, with a profile of 0.086 λh (λh is the free-space wavelength at 1.75 GHz), and achieves ±60° scanning in the E/H-planes, with the reflection coefficient below −7 dB. The proposed design method and all numerical results are experimentally verified by a 4 × 4 CPA prototype.

Blueberry is an important horticultural plant that is very susceptible to drought. However, the molecular regulation mechanisms of blueberry tolerance to drought remain elusive. In this study, the transcriptome profile of blueberry by RNA-seq under different degrees of drought treatment were conducted and drought-related genes and pathways were screened using weighted gene co-expression network analysis (WGCNA) and Venn analysis. Interestingly, the leaves and roots of blueberry exhibited different expression patterns under drought treatment and differentially expressed genes (DEGs), GO terms and KEGG pathways were more enriched in leaves than in roots. The majority of DEGs were associated with signal transduction, transcriptional regulation, and metabolism. Eight key pathways and eight DEGs were shared both in leaves and roots. Notably, the pathway with the most core genes in leaves is the plant hormone signal transduction pathway, and in roots are the MAPK signaling pathway, reactive oxygen species metabolism and the key genes such as VcXTH3, VcPP2C51, and VcPNC1 were identified. For transcription factors, VcABR1, VcABF2, VcMYB108 and VcMYB93 are likely involved in drought response. In the metabolism category, VcCYP75A1 was likely involved in anthocyanin biosynthesis, and VcPNC1 in the monoterpenoid biosynthesis pathway. The eight DEGs markedly induced under drought exhibited differential expression in leaves and roots. Correspondingly, physiological assays showed that POD activity, ABA content, and anthocyanin biosynthesis in leaves and roots were significantly increased. Collectively, our study revealed the synergistic and distinct defense pathways and mechanisms in leaves and roots of blueberry and explored the potential regulatory network in blueberry response to drought stress.

Abstract Background Blueberry (Vaccinium corymbosum L.) is an important species with a high content of flavonoids in fruits. As a perennial shrub, blueberry is characterized by shallow-rooted property and susceptible to drought stress. MYB transcription factor was reported to be widely involved in plant response to abiotic stresses, however, the role of MYB family in blueberry responding to drought stress remains elusive. Results In this study, we conducted a comprehensive analysis of VcMYBs in blueberry based on the genome data under drought stress, including phylogenetic relationship, identification of differentially expressed genes (DEGs), expression profiling, conserved motifs, expression correlation and protein-protein interaction prediction, etc. The results showed that 229 non-redundant MYB sequences were identified in the blueberry genome, and divided into 23 subgroups. A total of 102 MYB DEGs with a significant response to drought stress were identified, of which 72 in leaves and 69 in roots, and 8 differential expression genes with a > 20-fold change in the level of expression. 17 DEGs had a higher expression correlation with other MYB members. The interaction partners of the key VcMYB proteins were predicted by STRING analysis and in combination with physiological and morphological observation. 10 key VcMYB genes such as VcMYB8, VcMYB102 and VcMYB228 were predicted to be probably involved in reactive oxygen species (ROS) pathway, and 7 key VcMYB genes (VcMYB41, VcMYB88 and VcMYB100, etc..) probably participated in leaf regulation under drought treatment. Conclusions Our studies provide a new understanding of the regulation mechanism of VcMYB family in blueberry response to drought stress, and lay fundamental support for future studies on blueberry grown in regions with limited water supply for this crop.

This paper presents simulation and measurement results of a wideband planar phased array for 5G. The desired wideband operation is achieved using a tightly coupled dipole array (TCDA). The proposed array consists of tightly coupled dipole units in dual-polarized configuration, and two thin parasitic layers separated apart by air gap for wide-angle impedance matching (WAIM). The top matching layer is loaded with a metasurface composed of sub-wavelength split-ring resonators (SRRs) to improve the scanning performance of array. The infinite array achieved a bandwidth from 23.5 to 29.5 GHz, with voltage standing wave ratio (VSWR) l, and it exhibits high gains, high efficiency > 71% (largest scan angle) and good cross-polarization. The simulations are validated by fabrication and measurement of an array prototype, which indicates agreement to simulated values. The proposed dual-polarized antenna array can be deployed in the future beam scanning applications for 5G.

In this paper, a dual-band dual-polarized antenna array is presented for 5G base station application. The developed antenna array consists of a 4 × 4 planar MIMO array operating at 3.3-5.0 GHz band (upper band UB) and a single antenna element working at 0.69-0.96 GHz band (lower band LB). The dual-band operation is based on our previously proposed antenna topology. The novelty of this paper is that the UB antenna array is a large-scale rectangular lattice array with 16 antenna elements for practical MIMO applications. Meanwhile, both the cross-band and in-band mutual coupling among the LB and UB antennas are furtherly suppressed by employing three decoupling techniques including rectangular ring resonator, ferrite chock ring, and novel baffle structure. With these decoupling technologies, the UB antenna array and the LB antenna are successfully integrated within a compact volume of 0.93λL× 0.93λL× 0.17λL (λL is the wavelength at 0.82 GHz). Experimental results show that the proposed dual-band antenna array offers high cross-band port isolation (>30 dB). Stable radiation patterns are also achieved for both the LB and UB antennas with averaged gain of 8.6 dBi and 7.3 dBi, respectively. The radiation efficiency is higher than 90% across the entire operation bands. It is the first time to realize a large scale sub-6 GHz MIMO antenna array shared-aperture working with a GSM band antenna element in a such compact volume.

Combining the inherent multiple beam capabilities of transmitarray antennas (TAAs) and the flexible fields launched by phased array antennas (PAAs), PAA-fed TAAs are proposed in this paper for high-gain and wide-angle beam scanning in millimeter-wave (MMW) band. After thoroughly analyzing the operating mechanisms of the PAA-fed TAAs, a divisionally multi-focal method is proposed to deploy the TAA elements, which can be better adapted to the PAA feed whereby the scanning performances are improved. Subsequently, two PAA-fed TAAs with feeding distance-to-diameter ratios (H/Ds) of mere 0.28 are numerically demonstrated at 39 GHz, wherein both TAAs are composed of the square subwavelength low-pass elements and the cavity-backed bowtie patch antenna is identified as the PAA feed element. Simulated results show that the first design example achieves a conical beam steering over ±30° with a 30.9 dBi peak gain and gain drop below 2.1 dB. The second design can scan across ±50°/±10° along the E/H planes, respectively, together with the gain losses of 3.3 and 1.6 dB from the peak value of 31.1 dBi. Finally, the first design case is fabricated and measured for experimental verification purpose, whose measured results agree reasonably well with the simulated ones.

This paper proposes an efficient and systematic design approach for tightly coupled dipole array (TCDA) designs. In this approach, the radiator structure and feeding structure are designed and optimized based on their equivalent circuit models (ECM) respectively. A novel ECM is proposed to accurately describe the impedance characteristics of the radiator structure with dual-diamond dipoles. The proposed ECM of the radiator structure keeps its accuracy for variable design parameters. The ECM of the proposed feeding structure is also developed to analyze its impedance characteristics. As compared with conventional brute-force optimizations based on full-wave simulations, the two ECMs make it easy and efficient to design wideband TCDAs. A dual-polarized TCDA is designed with the proposed approach to illustrate the efficiency of the approach. The resultant TCDA operates in a wide frequency band of 0.87-10.14 GHz with VSWR ≤2 for broadside radiation. Meanwhile, the VSWR value under all conditions (broadside, ±60° scanning in E- and H-planes) remains ≤3 over the frequency band of 0.8-9 GHz. A 10 × 10 prototype is fabricated to demonstrate the design.

The heterogeneous Fenton system has drawn great attention in recent years due to its effective degradation of polluted water capability without limitation of the pH range and avoiding excess ferric hydroxide sludge. Therefore, simple chemical precipitation and vacuum filtration method for manufacturing the heterogeneous Fenton aramid nanofibers (ANFs)/ferrous oxalate (FeC2O4) composite membrane catalysts with excellent degradation of methylene blue (MB) is reported in the study. The morphology and structure of materials synthesized were characterized by scanning electron microscope (SEM), X-ray energy spectrum analysis (EDS), infrared spectrometer (FTIR), and X-ray diffraction (XRD) equipment. The 10 ppm MB degradation efficiency of composite catalyst and ferrous oxalate (FeC2O4) within 15 min were 94.5% and 91.6%, respectively. The content of methylene blue was measured by a UV-Vis spectrophotometer. Moreover, the dye degradation efficiency still could achieve 92% after five cycles, indicating the composite catalyst with excellent chemical stability and reusability. Simultaneously, the composite catalyst membrane can degrade not only MB but also rhodamine B (RB), orange II (O II), and methyl orange (MO). This study represents a new avenue for the fabrication of heterogeneous Fenton catalysts and will contribute to dye wastewater purification, especially in the degradation of methylene blue.

Camellia oleifera Abel. is an important woody oil species; however, the shortage of rapid and industrialized seedling culture is a large constraint on the development of the tea oil industry. Somatic embryogenesis (SE) is one of the main powerful biotechnological tools for plant mass regeneration, but the largely unknown SE in C. oleifera limits the scale production of clonal plants. In this study, we described a high-efficiency SE system via direct and indirect pathways in C. oleifera and investigated the effect of genotype, explant age and phytohormones on SE. In the direct pathway, somatic embryos were highly induced from immature seeds 220 days after full blossom, and the development of embryoids was achieved with a combination of 0.19 mg/L 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.05 mg/L thidiazuron (TDZ). In the indirect pathway, embryogenic calli were induced from the same explants in medium containing 1.5 mg/L 2,4-D, while 0.75 mg/L 2,4-D treatment led to high proliferation rates for embryogenic calli. The addition of 0.19 mg/L 2,4-D alone stimulated the production of globular embryos while causing a 75% loss of the induction rate in the heart embryo stage. Upon transfer of the globular embryos to phytohormone-free medium, an optimal induction rate of 62.37% from globular embryos to cotyledonary embryos was obtained. These data suggest that the subsequent differentiation process after the globular embryo stage in ISE is more similar to an endogenous phytohormones-driven process. Mature embryos germinated to produce intact plantlets on half-strength MS basal medium with a regeneration rate of 63.67%. Histological analysis confirmed the vascular bundle isolation of embryoids from the mother tissue. We further studied the different varieties and found that there were no significant genotype differences for SE induction efficiency in C. oleifera. Thus, we established a high-efficiency induction system for direct and indirect somatic embryogenesis (ISE) in C. oleifera and regenerated intact plantlets via SE, not organogenesis. ISE has a more complicated induction and regulatory mechanism than direct somatic embryogenesis. The improved protocol of SE would benefit mass propagation and genetic manipulation in C. oleifera.

A new 5 degree of freedom parallel mechanism is proposed for the special case of 5 degrees of freedom， and its kinematics is analyzed. Using the spiral theory and the modified G-K formula， the degree of freedom of the parallel mechanism is verified， and the inverse kinematics of the mechanism is solved by the closed loop vector method. The kinematics simulation of the mechanism is carried out based on the Matlab and Adams. The degree of freedom of the mechanism and the inverse kinematics curve obtained by Matlab and Adams are obtained. The correctness of the degree of freedom of the mechanism is verified by Adams simulation， and the correctness of the inverse solution of the mechanism is verified by comparing the inverse kinematics curves of Matlab and Adams.

This paper presents an extremely flat-beam cylindrical lens antenna with a 180 mm ($36~\lambda$ ) diameter lens at 60 GHz. The parameters of lens antennas in the horizontal plane i.e. dielectric constants, radii, and focal length are optimized to widen beams in the vertical plane while obtaining pencil beams in the horizontal plane. The optimization procedure consists of a theoretical method and differential evolution (DE) algorithm. This beam-widening idea is analyzed and proved to be feasible owing to cylindrical apertures, which is quite different from the results of antennas with planar apertures. Then, the permittivity distribution which results in an extremely flat beam is investigated and shows a novel S-shape rather than following either the law of modified Luneberg lens or the Luneberg's Law. Finally, the proposed lens antenna is fabricated and measured. At the design frequency of 60 GHz, the measured 3-dB E- and H-plane beamwidths separately are 100.4° and 2.3°. As compared to the gain peak, the measured and simulated gain drop at ±60° in the E-plane are less than 4 dB and 5 dB, respectively. Measured results show good agreements with the simulated results, thus validating the extremely flat beam of the proposed lens antenna and the effectiveness of the optimization procedure.

A key challenge in the new generation of advanced phased arrays is to realize wideband and wide-scanning performances while maintaining lower scattering characteristics. In this paper, a black box method (BBM) is proposed for accelerating balanced optimization of radiation and monostatic scattering characteristics of an antenna element in an infinite periodic environment. To validate the method, a common tightly coupled dipole array (TCDA) with unbalanced feed scheme is considered. Besides, the indium tin oxide (ITO) film is introduced to further improve the wide-angle scanning and monostatic scattering reduction abilities. Finally, a 10 × 10 single-polarized TCDA prototype with ITO film is fabricated and measured. Measured results are in good agreement with simulation results and demonstrate that the TCDA has a balanced radiation and scattering characteristics, such as an active VSWR

The inherent brittleness of poly(lactic acid) (PLA) usually limits its application in the high ductile requirements sector. To address the above issue, n-ethyl-p-toluenesulfonamide (N-PTSA) as the toughening agent, was utilized to optimize the rheological and mechanical performance of the PLA matrix. The microstructure, thermal stability, rheological behavior, and mechanical properties of PLA/N-PTSA were systematically investigated. A rheological test showed that N-PTSA can reduce the melt processing viscosity of PLA matrix and the decreasing of processing viscosity strongly depended on the N-PTSA content rather than shear rate. Mechanical properties results confirmed that the 14.7% N-PTSA can improve the toughness of PLA/N-PTSA without deteriorating the tensile strength and Yong’s modulus. This reason was ascribed to the reduction of hydrogen bonds of PLA matrix caused by N-PTSA to accelerate the movement of PLA molecular chain meanwhile forming new hydrogen bond between PLA and N-PTSA. By adding N-PTSA, the thermal stability of PLA was decreased. With the synergistic effect of plasticizing and toughening N-PTSA, the rheology and mechanical properties of PLA had been effectively improved.

Camellia (C.) oleifera Abel. is an evergreen small arbor with high economic value for producing edible oil that is well known for its high level of unsaturated fatty acids. The yield formation of tea oil extracted from fruit originates from the leaves, so leaf senescence, the final stage of leaf development, is an important agronomic trait affecting the production and quality of tea oil. However, the physiological characteristics and molecular mechanism underlying leaf senescence of C. oleifera are poorly understood. In this study, we performed physiological observation and de novo transcriptome assembly for annual leaves and biennial leaves of C. oleifera. The physiological assays showed that the content of chlorophyll (Chl), soluble protein, and antioxidant enzymes including superoxide dismutase, peroxide dismutase, and catalase in senescing leaves decreased significantly, while the proline and malondialdehyde concentration increased. By analyzing RNA-Seq data, we identified 4645 significantly differentially expressed unigenes (DEGs) in biennial leaves with most associated with flavonoid and phenylpropanoid biosynthesis and phenylalanine metabolism pathways. Among these DEGs, 77 senescence-associated genes (SAGs) including NOL, ATAF1, MDAR, and SAG12 were classified to be related to Chl degradation, plant hormone, and oxidation pathways. The further analysis of the 77 SAGs based on the Spearman correlation algorithm showed that there was a significant expression correlation between these SAGs, suggesting the potential connections between SAGs in jointly regulating leaf senescence. A total of 162 differentially expressed transcription factors (TFs) identified during leaf senescence were mostly distributed in MYB (myeloblastosis), ERF (Ethylene-responsive factor), WRKY, and NAC (NAM, ATAF1/2 and CUCU2) families. In addition, qRT-PCR analysis of 19 putative SAGs were in accordance with the RNA-Seq data, further confirming the reliability and accuracy of the RNA-Seq. Collectively, we provide the first report of the transcriptome analysis of C. oleifera leaves of two kinds of age and a basis for understanding the molecular mechanism of leaf senescence.

α-MoO3 has been used as a hydrogen sensing material due to its excellent properties and unique crystalline layer structure. However, the low repeatability of α-MoO3 based hydrogen sensor restricts its practical application. In this paper, the effect of intercalated ion species and the amount in α-MoO3 is experimentally investigated and discussed. It is concluded that the repeatability of the sensor depends on the radius of intercalated ions and amount of ionic bonds. The optimal ion species is Na+ and the optimal amount of precursor is 1 mmol.

A characteristic mode (CM) formulation is developed for the modal analysis of microstrip antennas. It is derived from the mixed-potential integral equation (MPIE) with spatial-domain Green’s functions for multilayered media, where spatial-domain Green’s functions take into account the effect of the multilayered media. The resultant characteristic currents and fields are orthogonal with each other among different orders of modes. Together with the eigenvalues and their deduced indicators, the CMs provide deep physical insights into the radiation mechanisms of microstrip antennas. Numerical results are presented to confirm CM formulation’s effectiveness and accuracy in determining the resonant frequencies, radiating mode currents, and modal fields of microstrip antennas. As opposed to the very popular CM formulation for conducting bodies, comparative studies are presented to show the quite different modal analysis results by considering the multilayered media.

Traditional monopulse systems used for direction finding usually face the contradiction between high angle precision and wide angle-searching field, and a compromise has to be made. In this paper, the time modulation technique in four-dimensional (4D) antenna array is introduced into the conventional phase-comparison monopulse to form a novel direction-finding system, in which both high angle resolution and wide field-of-view are realized. The full 4D array is divided into two subarrays and the differential evolution (DE) algorithm is used to optimize the time sequence of each subarray to generate multibeams at the center frequency and low sidebands. Then the multibeams of the two subarrays are phase-compared with each other and multiple pairs of sum-difference beams are formed at different sidebands and point to different spatial angles. The proposed direction-finding system covers a large field-of-view of up to ±60° and simultaneously maintains the advantages of monopulse systems, such as high angle precision and low computation complexity. Theoretical analysis and experimental results validate the effectiveness of the proposed system.