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Abstract Wireless local area network (WLAN) has gained widespread application as a convenient network access method, demanding higher network efficiency, stability, and responsiveness. High-performance filters are crucial components to meet these needs. Film bulk acoustic resonators (FBARs) are ideal for constructing these filters due to their high-quality factor (Q) and low loss. In conventional air-gap type FBAR, aluminum nitride (AlN) is deposited on the sacrificial layer with poor crystallinity. Additionally, FBARs with single-crystal AlN have high internal stress and complicated fabrication process. These limit the development of FBARs to higher frequencies above 5 GHz. This paper presents the design and fabrication of FBARs and filters for WLAN applications, combining the high electromechanical coupling coefficient ( $${K}_{{\rm{t}}}^{2}$$ K t 2 ) of Al0.8Sc0.2N film with the advantages of the thin film transfer process. An AlN seed layer and 280 nm-thick Al0.8Sc0.2N are deposited on a Si substrate via physical vapor deposition (PVD), achieving a full width at half maximum (FWHM) of 2.1°. The ultra-thin film is then transferred to another Si substrate by wafer bonding, flipping, and Si removal. Integrating conventional manufacturing processes, an FBAR with a resonant frequency reaching 5.5 GHz is fabricated, demonstrating a large effective electromechanical coupling coefficient ( $${{k}}_{{\rm{eff}}}^{2}$$ k eff 2 ) of 13.8% and an excellent figure of merit (FOM) of 85. A lattice-type filter based on these FBARs is then developed for the Wi-Fi UNII-2 band, featuring a center frequency of 5.5 GHz and a −3 dB bandwidth of 306 MHz, supporting high data rates and large throughputs in WLAN applications.

Abstract The high-frequency and high-quality factor characteristics of bulk acoustic wave (BAW) resonators have significantly advanced their application in sensing technologies. In this work, a fluidic sensor based on a BAW resonator structure is fabricated and investigated. Embedded microchannels are formed beneath the active area of the BAW device without the need for external processes. As liquid flows through the microchannel, pressure is exerted on the upper wall (piezoelectric film) of the microchannel, which causes a shift in the resonant frequency. Using density functional theory, we revealed the intrinsic mechanism by which piezoelectric film deformation influences BAW resonator performance. Theoretically, the upwardly convex piezoelectric film caused by liquid flow can increase the resonant frequency. The experimental results obtained with ethanol solutions of different concentrations reveal that the sensor, which operates at a high resonant frequency of 2.225 GHz, achieves a remarkable sensitivity of 5.1 MHz/% (221 ppm/%), with an ultrahigh linearity of 0.995. This study reveals the intrinsic mechanism of liquid sensing based on BAW resonators, highlights the potential of AlN/Al0.8Sc0.2N composite film BAW resonators in liquid sensing applications and offers insights for future research and development in this field.

Abstract The first-order antisymmetric (A1) mode lamb wave resonator (LWR) based on Z-cut LiNbO3 thin films has attracted significant attention and is widely believed to be a candidate for next-generation reconfigurable filters with high frequency and large bandwidth (BW). However, it is challenging for traditional interdigitated electrodes (IDTs) based LWR filters to meet the requirement of a clean frequency spectrum response and enough out-of-band (OoB) rejection. To solve the problem, we propose LWRs with checker-shaped IDTs for the design of filters that meet the Wi-Fi 6E standard. By taking advantage of checker-shaped IDTs with unparalleled boundaries, the fabricated 6-GHz resonators successfully suppress higher-order A1 spurious modes, demonstrating a spurious-free impedance response and a high figure-of-merit (FOM) up to 104. Based on the demonstrated checker-shaped electrode design, the filter features a center frequency (f 0 ) of more than 6 GHz, a 3 dB BW exceeding 620 MHz, and an excellent OoB rejection >25 dB, consistent with the acoustic-electric-electromagnetic (EM) multi-physics simulations. Furthermore, through the capacitance-inductance matching network technology, the filter’s voltage standing wave ratio (VSWR) is successfully reduced below 2, showing an excellent 50 Ω impedance matching. This study lays a foundation for ultra-high-frequency and ultra-wideband filters for the Wi-Fi 6/6E application.

BackgroundCitrullinemia type I disorders (CTLN1) is a genetic metabolic disease caused by argininosuccinate synthetase (ASS1) gene mutation. To date, the human genome mutation database has documented over 100 variants of the ASS1 gene. This study reported a novel deletion-insertion variant of ASS1 gene and employed various prediction tools to determine its pathogenicity.MethodsWe reported a case of early-onset CTLN1. Whole exome sequencing was conducted to identify genetic mutations. We employed various structure prediction tools to generate accurate 3D models and utilized computational biology tools to elucidate the disparities between the wild-type and mutant proteins.ResultsThe patient was characterized by severe clinical manifestations, including poor responsiveness, lethargy, convulsions, and cardiac arrest. Notably, the patient exhibited significantly elevated blood ammonia levels (655 μmol/L; normal reference: 10–30 μmol/L) and increased citrulline concentrations (936 μmol/L; normal reference: 5–25 μmol/L). Whole exome sequencing revealed a in-frame deletion-insertion mutation c.1128_1134delinsG in the ASS1 gene of unknown significance, which has not been previously reported. Our finding indicated that the C- terminal helix domain of the mutant protein structure, which was an important structure for ASS1 protein to form protein tetramers, was indeed more unstable than that of the wild-type protein structure.ConclusionThrough conducting an in silico analysis on this unique in-frame deletion-insertion variant of ASS1, our aim was to enhance understanding regarding its structure-function relationship as well as unraveling the molecular mechanism underlying CTLN1.

Abstract Combinatorial optimization (CO) has a broad range of applications in various fields, including operations research, computer science, and artificial intelligence. However, many of these problems are classified as nondeterministic polynomial‐time (NP)‐complete or NP‐hard problems, which are known for their computational complexity and cannot be solved in polynomial time on traditional digital computers. To address this challenge, continuous‐time Ising machine solvers have been developed, utilizing different physical principles to map CO problems to ground state finding. However, most Ising machine prototypes operate at speeds comparable to digital hardware and rely on binarizing node states, resulting in increased system complexity and further limiting operating speed. To tackle these issues, a novel device‐algorithm co‐design method is proposed for fast sub‐optimal solution finding with low hardware complexity. On the device side, a piezoelectric lithium niobate (LiNbO3) microelectromechanical system (MEMS) oscillator network‐based Ising machine without second‐harmonic injection locking (SHIL) is devised to solve Max‐cut and graph coloring problems. The LiNbO3 oscillator operates at speeds greater than 9 GHz, making it one of the fastest oscillatory Ising machines. System‐wise, an innovative grouping method is used that achieves a performance guarantee of 0.878 for Max‐cut and 0.658 for graph coloring problems, which is comparable to Ising machines that utilize binarization.

Abstract Multiferroic materials offer a promising avenue for manipulating digital information by leveraging the cross-coupling between ferroelectric and ferromagnetic orders. Despite the ferroelectricity has been uncovered by ion displacement or interlayer-sliding, one-unit-cell of multiferroic materials design and wafer-scale synthesis have yet to be realized. Here we develope an interface modulated strategy to grow 1-inch one-unit-cell of non-layered chromium sulfide with unidirectional orientation on industry-compatible c-plane sapphire. The interfacial interaction between chromium sulfide and substrate induces the intralayer-sliding of self-intercalated chromium atoms and breaks the space reversal symmetry. As a result, robust room-temperature ferroelectricity (retaining more than one month) emerges in one-unit-cell of chromium sulfide with ultrahigh remanent polarization. Besides, long-range ferromagnetic order is discovered with the Curie temperature approaching 200 K, almost two times higher than that of bulk counterpart. In parallel, the magnetoelectric coupling is certified and which makes 1-inch one-unit-cell of chromium sulfide the largest and thinnest multiferroics.

For modular multilevel converter-based battery energy storage systems (MMC-BESS), uneven power among batteries of SMs will be deduced by battery aging, battery fault, etc., which will degrade performance and even lead to system failure. For maintaining the balance of capacitor voltage, this paper analyzes the limits of the uneven power of batteries, which are presented as the current limits in this paper. According to analysis, an analytical method is proposed that only the dc and fundamental frequency components of the arm current are used to calculate current limits. With the current limits it is able to evaluate the reasonability of power distribution among batteries. Meanwhile, increase of fundamental frequency component will enhance the current limits, and the dc component determines the size relationship between the absolute values of the upper and lower current limits. Finally, simulation model and experiment prototype are built for verifying the theoretical analysis and current limits calculation method, and satisfactory results are provided.

Intimal hyperplasia is one of the common pathophysiological foundations of vascular remodeling including restenosis and atherosclerosis. The Rho GTPase activating protein 24 (ARHGAP24) has been reported as a tumor suppressor in multiple cancers. Nevertheless, the role of ARHGAP24 in intimal hyperplasia is unclear. Interestingly, our results showed that ARHGAP24 was significantly up-regulated in dedifferentiated VSMC in vitro and vivo, which suggested that ARHGAP24 could promote VSMC dedifferentiation and proliferation. Knockdown of ARHGAP24 effectively inhibited VSMC dedifferentiation and proliferation in the absence and present of PDGF-BB, which might inactivate both ATK and ERK1/2 signaling pathways. Moreover, AAV9-mediated silencing of Arhgap24 also alleviates VSMC dedifferentiation and proliferation in the wire-injured mouse femoral arteries, contributing to reducing neointima formation. AAV9-mediated overexpression of Arhgap24 exacerbates intimal hyperplasia. We demonstrate that decreased ARHGAP24 expression restrained VSMC proliferation and dedifferentiation possibly by inactivating both AKT and ERK1/2 signaling pathways, which may provide a potential therapeutic strategy for diseases associated with intimal hyperplasia including restenosis and atherosclerosis.

Abstract RNA interference (RNAi) is a powerful tool for understanding and manipulating signaling pathways in plant science, potentially facilitating the accelerated development of novel plant traits and crop yield improvement. The common strategy for delivering siRNA into intact plants using agrobacterium or viruses is complicated and time‐consuming, limiting the application of RNAi in plant research. Here, a novel delivery method based on mesoporous silica nanoparticles (MSNs) is reported, which allows for the efficient delivery of siRNA into mature plant leaves via topical application without the aid of mechanical forces, achieving transient gene knockdown with up to 98% silencing efficiency at the molecular level. In addition, this method is nontoxic to plant leaves, enabling the repeated delivery of siRNA for long‐term silencing. White spots and yellowing phenotypes are observed after spraying the MSN‐siRNA complex targeted at phytoene desaturase and magnesium chelatase genes. After high light treatment, photobleaching phenotypes are also observed by spraying MSNs‐siRNA targeted at genes into the Photosystem II repair cycle. Furthermore, the study demonstrated that MSNs can simultaneously silence multiple genes. The results suggest that MSN‐mediated siRNA delivery is an effective tool for long‐term multi‐gene silencing, with great potential for application in plant functional genomic analyses and crop improvement.

With the development of globalization and artificial intelligence, as well as the outbreak of COVID-19, unmanned vehicles have played an important role in cargo distribution. In order to better analyze the research directions of unmanned vehicle distribution, this paper summarizes the models and algorithms of unmanned vehicle distribution optimization. The research results show that most of the studies have established the goal of optimizing the total costs or travel time. Many researchers have begun to study multi-objective optimization problems, but there are certain limitations, so some studies convert these problems into single-objective optimization for solving, such as converting time and energy consumption into cost, waiting time into distance, and time delay into penalty cost. With the development of unmanned vehicle distribution technology, in future research, a multi-objective model with the lowest cost, the shortest distance and the best security should be established and solved. Most studies have proposed heuristic algorithms for solving the unmanned vehicle distribution problem, and improved optimization solutions have been obtained. In order to ensure the diversity of solution methods, and give consideration to solution time and solution quality, hybrid methods with other algorithms will be a future research direction, for example, the combination of heuristic algorithm and exact algorithm. With the gradual deepening of research, integrated distribution of multiple types of unmanned equipment will become the focus of future research.

Research into bird habitat selection can unveil the impact of specific habitat characteristics on bird survival. However, empirical information on the environmental factor preferences and differences within the yew ecological garden for birds is still lacking. This study was conducted in a yew ecological garden located in the southern experimental area of the Meihua Mountain National Nature Reserve, Fujian Province, China. We selected three commonly occurring bird species for analysis to discern the factors influencing habitat selection and interspecific differences and the impact of habitat environmental factors. Canopy density and coverage were identified as dominant factors influencing habitat selection for the Red-billed Blue Magpie (Urocissa erythrorhyncha), Black Bulbul (Hypsipetes leucocephalus), and Orange-bellied Leafbird (Chloropsis hardwickii). The height of perching trees, average tree height, and average diameter at breast height were all important determinants for the habitat selection of Red-billed Blue Magpie and Black Bulbul. These dominant factors were consistent with logistic regression analysis results. Both one-way ANOVA and stepwise discriminant analysis revealed significant differences in habitat selection among three commonly occurring bird species. Our results provide important insights into avian habitat selection in patchy habitats, which can be used as a guideline for future conservation and habitat management.

Duck species are important vectors for seed dispersal of many plants, contributing significantly to the regeneration of wetland plant communities. However, research on the temporal changes in diet and the dynamics and differences of seed dispersal among different duck species is still limited. In this study, we analyzed the diversity of duck community and the diversity of seeds in the feces of different duck species from December to February for 2022–23 and 2023–24 in the coastal wetland of Dafeng, eastern Jiangsu Province, China. A total of 13 duck species were recorded in the four habitats, of which Spot-billed Ducks (Anas zonorhyncha) and Mallards (A. platyrhynchos) were the most abundant. The diversity and abundance of ducks vary across different habitats, and tidal flat supports the greatest diversity and abundance of ducks. We collected fecal samples from Spot-billed Ducks, Gadwalls (Mareca strepera), Mallards, and Eurasian Teals (A. crecca) in the tidal flat, from which seeds belonging to 7 families, 13 genera and 15 different plant species were obtained. There were significant differences in seed dispersal among the four duck species, which varied with the season. Gadwalls and Common Teals showed more significant diversity in seed dispersal, with their feces containing a greater variety of plant seeds, which is related to their broader dietary range and ecological adaptability. Furthermore, the seasonal variation in the number of seeds per feces reflected the availability of seeds in the habitat and the response of ducks to environmental changes, while variations in seed intake among different duck species may be associated with inter-annual weather condition changes. The results of this study will provide a new perspective for understanding the mechanisms of bird-mediated seed dispersal in coastal wetland and offer preliminary insights for the seed dispersal by Asian ducks.

Summary: Gekko japonicus possesses flexible climbing and detoxification abilities under insectivorous habits. Still, the evolutionary mechanisms behind these traits remain unclarified. This study presents a chromosome-level G. japonicus genome, revealing that its evolutionary breakpoint regions were enriched with specific repetitive elements and defense response genes. Gene families unique to G. japonicus and positively selected genes are mainly enriched in immune, sensory, and nervous pathways. Expansion of bitter taste receptor type 2 primarily in insectivorous species could be associated with toxin clearance. Detox cytochrome P450 in G. japonicus has undergone more birth and death processes than biosynthesis-type P450 genes. Proline, cysteine, glycine, and serine in corneous beta proteins of G. japonicus might influence flexibility and setae adhesiveness. Certain thermosensitive transient receptor potential channels under relaxed purifying selection or positive selection in G. japonicus might enhance adaptation to climate change. This genome assembly offers insights into the adaptive evolution of gekkotans.

IntroductionPregnancy outcomes of patients with systemic lupus erythematosus (SLE) have improved over the past four decades, leading to an increased desire for pregnancy among this cohort. However, the offspring of patients with SLE still face the risks of preterm birth, low birth weight, learning disabilities, and neurological disorders, while the causes underlying these risks remain unclear.MethodsIn this study, we analyzed the blood metabolic features of neonates born to 30 SLE patients and 52 healthy control mothers by employing tandem mass spectrometry with the dual aims of identifying the etiology of metabolic features specific to infants born from mothers with SLE and providing new insights into the clinical management of such infants.ResultsWe found significant differences in serum metabolite levels between infants born from mothers with SLE and those born from mothers without SLE, including 15 metabolites with reduced serum levels. Further analysis revealed a disrupted tyrosine metabolism pathway in the offspring of mothers with SLE.DiscussionBy constructing a composite model incorporating various factors, such as serum tyrosine levels, gestational age, and birth weight, we were able to accurately differentiate between newborns of SLE and non-SLE pregnancies. Our data reveal significant differences in serum concentrations of amino acids and acylcarnitines in newborns born to mothers with SLE. We conclude that the reduction of blood L-tyrosine levels is a feature that is characteristic of adverse neurological outcomes in infants born from mothers with SLE.

ObjectivePatients with necrotizing enterocolitis display severe gastrointestinal complications of prematurity, but the mechanism driving this clinical profile remains unknown. We used mass cytometry time-of-flight to characterize and compare immune cell populations in the blood and intestine tissue from patients with and without (controls) necrotizing enterocolitis at single-cell resolution.MethodsWe completed a deep mapping of the immune system of the peripheral blood mononuclear cells and intestinal mucosa tissue using mass cytometry to evaluate immune cell types, which revealed global immune dysregulation characteristics underlying necrotizing enterocolitis.ResultsCompared with controls, natural killer cells display signs of heightened activation and increased cytotoxic potential in the peripheral blood and mucosa of patients with necrotizing enterocolitis. Furthermore, CD4+ T effector memory cells, non-classical monocytes, active dendritic cells, and neutrophils were specifically enriched in the mucosa, suggesting trafficking from the periphery to areas of inflammation. Moreover, we mapped the systemic and local distinct immune signatures suggesting patterns of cell localization in necrotizing enterocolitis.ConclusionWe used mass cytometry time-of-flight technology to identify immune cell populations specific to the peripheral blood and intestinal mucosa tissue from patients with necrotizing enterocolitis and controls. This information might be used to develop precise diagnosis and therapies that target specific cell populations in patients with necrotizing enterocolitis.

Film bulk acoustic-wave resonators (FBARs) are widely utilized in the field of radio frequency (RF) filters due to their excellent performance, such as high operation frequency and high quality. In this paper, we present the design, fabrication, and characterization of an FBAR filter for the 3.0 GHz–3.2 GHz S-band. Using a scandium-doped aluminum nitride (Sc0.2Al0.8N) film, the filter is designed through a combined acoustic–electromagnetic simulation method, and the FBAR and filter are fabricated using an eight-step lithographic process. The measured FBAR presents an effective electromechanical coupling coefficient (keff2) value up to 13.3%, and the measured filter demonstrates a −3 dB bandwidth of 115 MHz (from 3.013 GHz to 3.128 GHz), a low insertion loss of −2.4 dB, and good out-of-band rejection of −30 dB. The measured 1 dB compression point of the fabricated filter is 30.5 dBm, and the first series resonator burns out first as the input power increases. This work paves the way for research on high-power RF filters in mobile communication.

With the development of wireless communication, increasing signal processing presents higher requirements for radio frequency (RF) systems. Piezoelectric acoustic filters, as important elements of an RF front-end, have been widely used in 5G-generation systems. In this work, we propose a Sc0.2Al0.8N-based film bulk acoustic wave resonator (FBAR) for use in the design of radio frequency filters for the 5G mid-band spectrum with a passband from 3.4 to 3.6 GHz. With the excellent piezoelectric properties of Sc0.2Al0.8N, FBAR shows a large Keff2 of 13.1%, which can meet the requirement of passband width. Based on the resonant characteristics of Sc0.2Al0.8N FBAR devices, we demonstrate and fabricate different ladder-type FBAR filters with second, third and fourth orders. The test results show that the out-of-band rejection improves and the insertion loss decreases slightly as the filter order increases, although the frequency of the passband is lower than the predicted ones due to fabrication deviation. The passband from 3.27 to 3.47 GHz is achieved with a 200 MHz bandwidth and insertion loss lower than 2 dB. This work provides a potential approach using ScAlN-based FBAR technology to meet the band-pass filter requirements of 5G mid-band frequencies.

Abstract Bulk acoustic wave (BAW) filters have been extensively used in consumer products for mobile communication systems due to their high performance and standard complementary metal-oxide-semiconductor (CMOS) compatible integration process. However, it is challenging for a traditional aluminum nitride (AlN)-based BAW filter to meet several allocated 5G bands with more than a 5% fractional bandwidth via an acoustic-only approach. In this work, we propose an Al0.8Sc0.2N-based film bulk acoustic wave resonator (FBAR) for the design of radio frequency (RF) filters. By taking advantage of a high-quality Al0.8Sc0.2N thin film, the fabricated resonators demonstrate a large K eff 2 of 14.5% and an excellent figure of merit (FOM) up to 62. The temperature coefficient of frequency (TCF) of the proposed resonator is measured to be −19.2 ppm/°C, indicating excellent temperature stability. The fabricated filter has a center frequency of 4.24 GHz, a −3 dB bandwidth of 215 MHz, a small insertion loss (IL) of 1.881 dB, and a rejection >32 dB. This work paves the way for the realization of wideband acoustic filters operating in the 5G band.

This paper introduces a piezoelectric ring resonator, comprising a Mo-ScAlN-Mo sandwich structure and shaped into a ring with a hollow center. The vibrational modes of the resonator are elucidated through simulation and theoretical analysis, and the impact of diverse geometric parameters on the resonant frequency is explored. A HF resonator with a resonance frequency of 4.168 GHz has been fabricated. The electrical parameters of this resonator are extracted by fitting the Modified Butterworth-Van Dyke equivalent circuit model and the measured results. This work establishes a theoretical foundation for designing resonators with adjustable frequencies on a single wafer.

Abstract During MEMS device fabrication process, the residual stress of thin film caused by thermal expansion coefficient mismatch and lattice mismatch is an important factor that will deteriorate the properties of thin film and bring yield losses to MEMS devices. In this work, a method to release the residual stress by using a folded structure with V‐shaped grooves is proposed. The folded structures with different groove width and groove interval are fabricated and relative Raman frequency shift is adopted to calculate the residual stress. The minimum residual thermal stress of 11.6 MPa can be obtained in the folded structure models by simulation, which is about five times lower than the residual thermal stress of the flat structure. The minimum residual stress of 40 MPa can be obtained in the folded structure by experiment results, which is about 20 times lower than the residual stress of the flat structure. The simulation results and experimental analysis confirms that introducing a folded structure with groove into the design of MEMS device is an effective way to suppress the generation of residual stress, thus enhancing the reliability of MEMS devices.

Isolated methylmalonic acidemia (MMA) is an inherited organic acid metabolic disorder in an autosomal recessive manner, caused by mutations in the methylmalonyl coenzyme A mutase gene, and the isolated MMA patients often suffer from multi-organ damage. The present study aimed to profile the differential proteome of serum between isolated MAA patients and healthy control. The in vivo proteome of isolated MAA patients and healthy subjects was detected by an isobaric tag for relative and absolute quantitation (iTRAQ). A total of 94 differentially expressed proteins (DEPs) were identified between MMA patients and healthy control, including 58 upregulated and 36 downregulated DEPs in MMA patients. Among them, the most significantly upregulated proteins were CRP and immunoglobulins, and the top five most significantly downregulated proteins were all different types of immunoglobulins in MMA patients. GO analysis showed that these DEPs were mainly enriched in immune-related function and membrane protein-related function. KEGG revealed that these DEPs were mainly enriched in lysosome and cholesterol metabolism pathways. Also, these DEPs were predicted to contribute to lipid metabolic diseases. We addressed the proteomes of isolated MMA patients and identified DEPs. Our study expands our current understanding of MMA, and the DEPs could be valuable for designing alternative therapies to alleviate MMA symptoms.

High-resolution ophthalmic imaging devices including spectral-domain and full-field optical coherence tomography (SDOCT and FFOCT) are adversely affected by the presence of continuous involuntary retinal axial motion. Here, we thoroughly quantify and characterize retinal axial motion with both high temporal resolution (200,000 A-scans/s) and high axial resolution (4.5 μm), recorded over a typical data acquisition duration of 3 s with an SDOCT device over 14 subjects. We demonstrate that although breath-holding can help decrease large-and-slow drifts, it increases small-and-fast fluctuations, which is not ideal when motion compensation is desired. Finally, by simulating the action of an axial motion stabilization control loop, we show that a loop rate of 1.2 kHz is ideal to achieve 100% robust clinical in-vivo retinal imaging.

Abstract Background Remnant microhabitats are important for bird habitat selection and plant regeneration in the fragmented habitat. However, empirical information on the consequences of how microhabitat use by birds affects the early recruitment of plants is lacking. Methods In this study, we evaluated whether microhabitat selection by the Black Bulbul (Hypsipetes leucocephalus) (J. F. Gmelin, 1789) impacts the early recruitment of the endangered tree species, the Chinese Yew (Taxus chinensis (Pilger) Rehd), in a fragmented forest over a 4-year period (2011–2012, 2018–2019). Results Our results showed the main factors affecting H. leucocephalus microhabitat selection were distance to the nearest T. chinensis mature tree, herb cover and density, leaf litter cover, and vegetation type. Moreover, the results of logistic regression also highlighted the importance of elevation, distance to light gap and roads, tree cover in bird microhabitat selection. Furthermore, the seed emergence rate in microhabitats used by birds did not differ from the natural forest, which was related to five factors of bird microhabitat. The Random Forest model showed that seedling emergence rate was increased with leaf litter cover and distance to fallen dead trees, but decreased in relation to herb cover, slope, and elevation. Conclusion Our results highlight the importance of remnant microhabitats in fragmented forests for sustaining forest ecology and optimal management. The contribution of microhabitats used by birds to plant recruitment provides insights into how frugivore species contribute to plant regeneration, which should be incorporated in future conservation and management practices of fragmented forests.

In this paper, we present a comprehensive study on the propagation and dispersion characteristics of A1 mode propagating in Z-cut LiNbO3 membrane. The A1 mode resonators with pentagon spiral electrodes utilizing Z-cut lithium niobate (LiNbO3) thin film are designed and fabricated. The proposed structure excites the A1 mode waves in both x- and y-direction by utilizing both the piezoelectric constants e24 and e15 due to applying voltage along both the x- and y-direction by arranging pentagon spiral electrode. The fabricated resonator operates at 5.43 GHz with no spurious mode and effective electromechanical coupling coefficient (Keff2) of 21.3%, when the width of electrode is 1 µm and the pitch is 5 µm. Moreover, we present a comprehensive study of the effect of different structure parameters on resonance frequency and Keff2 of XBAR. The Keff2 keeps a constant with varied thickness of LiNbO3 thin film and different electrode rotation angles, while it declines with the increase of p from 5 to 20 µm. The proposed XBAR with pentagon spiral electrodes realize high frequency response with no spurious mode and tunable Keff2, which shows promising prospects to satisfy the needs of various 5 G high-band application.

Piezoelectric aluminum nitride (AlN) thin film, as a commonly used material for high-frequency acoustic resonators, has been a research hotspot in the RF field. Doping Sc elements in AlN is one of most effective methods to improve the piezoelectricity of the material. In this work, the first principal calculation and Mori–Tanaka model are used to obtain the piezoelectric constants of AlN, ScAlN, and AlN/ScAlN composites. Then, five types of AlN/ScAlN thin films are prepared on 8 inch silicon substrates. The crystal quality, roughness, and stress distribution are measured to characterize the film quality. The results show that composite film can effectively solve the problem of abnormal grains and reduce the roughness. Finally, a lamb wave resonator with an AlN/Sc0.2Al0.8N composite working at 2.33 GHz is fabricated. The effective electromechanical coupling coefficient Keff2 is calculated to be 6.19%, which has the potential to design high-frequency broadband filters.

The arrival of the 5G era has promoted the need for filters of different bandwidths. Thin-film bulk acoustic resonators have become the mainstream product for applications due to their excellent performance. The Keff2 of the FBAR greatly influences the bandwidth of the filter. In this paper, we designed an AlN-based adjustable Keff2 FBAR by designing parallel capacitors around the active area of the resonator. The parallel capacitance is introduced through the support column structure, which is compatible with conventional FBAR processes. The effects of different support column widths on Keff2 were verified by finite element simulation and experimental fabrication. The measured results show that the designed FBAR with support columns can achieve a Keff2 value that is 25.9% adjustable.

This article presents a coordinated anti-collision path planning algorithm for marine surface vessels in complex multi-ship encounter. Unlike previous research that follows the optimization sequence one step after the other from the prospective of single ship, a multi-stage anti-collision strategy from the overall perspective is established based on the principles of Synergetic theory and Queueing theory, which guarantees the compliance with navigation practice and the coordination among ships' avoidance actions. The concept of an optimization echelon is proposed to help categorize the optimization priority. Then a Multilayer Coding Genetic Algorithm enables all ships belonging to the same optimization echelon participate in the decision-making process simultaneously. Furthermore, the quantitative model of encounter situation is refined through the sensibility analysis. Finally, simulation examples consisting different traffic scenarios are analysed to demonstrate the effectiveness and practicality of the proposed scheme.

Thrust tests of a linear synchronous motor (LSM) with its secondary made of coated superconducting coils were conducted via the built prototype over the traditional copper windings. A numerical model of the superconducting LSM was made and the measured data of experiment validate its reliability. The nonlinear resistivity of coated superconductor was electromagnetically modeled by resorting to the power law in conjunction with the constitutive relationship of conductor. Based on the numerical model, we carried out a set of transient studies to make a forecast about the superiority of the proposed high temperature superconducting (HTS) LSM, such as magnetic field distribution and the time evolution of thrust together with the speed in different loads and frequencies. The achieved results clearly confirm that the proposed HTS LSM has the advantages to work as a candidate for developing the high-thrust LSM with a large air gap.

Background: Increased frequency of CCR9+ CD4+ T cells in peripheral blood is linked to several gastrointestinal inflammatory diseases; however, its relationship with necrotizing enterocolitis (NEC) is not understood. We investigated whether the frequencies of CCR9+ CD4+ T cells and related subsets were increased in peripheral blood of both patients and mice with NEC. Methods: CCR9+ CD4+ T cells and related subsets were evaluated by flow cytometry in peripheral blood collected from both patients and mice with NEC and controls. The suppressive function of CCR9+ regulatory T (Treg) cells in NEC was assessed via in vitro suppression assay. An in vitro T cell polarization assay was performed to investigate the role of proinflammatory cytokines in Treg cell polarization. In vivo Treg cell polarization analysis was performed using NEC mice treated with anti-interleukin-6 (IL-6) receptor antibody. Findings: A higher proportion of CCR9+ CD4+ T cells occurred in peripheral blood of both patients and mice with NEC than in controls. Elevated CCR9+ CD4+ T cells were primarily CCR9+ IL-17-producing Treg cells, possessing features of conventional Treg cells, but their suppressive activity was seriously impaired and negatively correlated with the severity of intestinal tissue injury. IL-6 promoted polarization of CCR9+ Treg cells to CCR9+ IL-17-producing Treg cells, and blocking IL-6 signalling inhibited this conversion in vitro and ameliorated experimental NEC in vivo. Interpretation: Collectively, these data suggested that CCR9+ IL-17-producing Treg cells may be a biomarker of severity and highlight the possibility that antibodies targeting IL-6R could ameliorate NEC by modulating lymphocyte balance. Fund: This work was supported by the Science and Technology Planning Project of Guangdong Province, China (2017A020215100), the Science and Technology Foundation of Guangzhou, China (201704020086 and 201604020154), the Medical Scientific Research Foundation of Guangdong Province, China (A2017304 and A2014704), and the Social Science and Technology Development Foundation of Dongguan, China (2016108101037). Keywords: CCR9, Interleukin-6, IL-17-producing Treg cell, Necrotizing enterocolitis

Film bulk acoustic resonators (FBARs) with a desired effective electromechanical coupling coefficient (Keff2) are essential for designing filter devices. Using AlN/AlScN composite film with the adjustable thickness ratio can be a feasible approach to obtain the required Keff2. In this work, we research the resonant characteristics of FBARs based on AlN/AlScN composite films with different thickness ratios by finite element method and fabricate FBAR devices in a micro-electromechanical systems process. Benefiting from the large piezoelectric constants, with a 1 μm-thick Al0.8Sc0.2N film, Keff2 can be twice compared with that of FBAR based on pure AlN films. For the composite films with different thickness ratios, Keff2 can be adjusted in a relatively wide range. In this case, a filter with the specific N77 sub-band is demonstrated using AlN/Al0.8Sc0.2N composite film, which verifies the enormous potential for AlN/AlScN composite film in design filters.

Investigating the diurnal and seasonal variations of plant photosynthetic performance under future atmospheric CO2 conditions is essential for understanding plant adaptation to global change and for estimating parameters of ecophysiological models. In this study, diurnal changes of net photosynthetic rate (Anet), stomatal conductance (gs), and photochemical efficiency of PSII (Fv′/Fm′) were measured in two rice cultivars grown in the open-top-chambers at ambient (∼450 μmol mol–1) and elevated (∼650 μmol mol–1) CO2 concentration [(CO2)] throughout the growing season for 2 years. The results showed that elevated (CO2) greatly increased Anet, especially at jointing stage. This stimulation was acclimated with the advance of growing season and was not affected by either stomatal limitations or Rubisco activity. Model parameters in photosynthesis model (Vcmax, Jmax, and Rd) and two stomatal conductance models (m and g1) varied across growing stages and m and g1 also varied across (CO2) treatments and cultivars, which led to more accurate photosynthesis and stomatal conductance simulations when using these cultivar-, CO2-, and stage- specific parameters. The results in the study suggested that further research is still needed to investigate the dominant factors contributing to the acclimation of photosynthetic capacity under future elevated CO2 conditions. The study also highlighted the need of investigating the impact of other environmental, such as nitrogen and O3, and non-environmental factors, such as additional rice cultivars, on the variations of these parameters in photosynthesis and stomatal conductance models and their further impacts on simulations in large scale carbon and water cycles.

Chlorophyll content is an important indicator of winter wheat health status. It is valuable to investigate whether the relationship between spectral reflectance and the chlorophyll content differs under elevated CO2 condition. In this open-top chamber experiment, the CO2 treatments were categorized into ambient (aCO2; about 400 μmol⋅mol–1) or elevated (eCO2; ambient + 200 μmol⋅mol–1) levels. The correlation between the spectral reflectance and the chlorophyll content of the winter wheat were analyzed by constructing the estimation model based on red edge position, sensitive band and spectral index methods, respectively. The results showed that there was a close relationship between chlorophyll content and the canopy spectral curve characteristics of winter wheat. Chlorophyll content was better estimated based on sensitive spectral bands and difference vegetation index (DVI) under both aCO2 and eCO2 conditions, though the accuracy of the models varied under different CO2 conditions. The results suggested that the hyperspectral measurement can be effectively used to estimate the chlorophyll content under both aCO2 and eCO2 conditionsand could provide a useful tool for monitoring plants physiology and growth.

The development of MEMS acoustic resonators meets the increasing demand for in situ detection with a higher performance and smaller size. In this paper, a lithium niobate film-based S1 mode Lamb wave resonator (HF-LWR) for high-sensitivity gravimetric biosensing is proposed. The fabricated resonators, based on a 400-nm X-cut lithium niobate film, showed a resonance frequency over 8 GHz. Moreover, a PMMA layer was used as the mass-sensing layer, to study the performance of the biosensors based on HF-LWRs. Through optimizing the thickness of the lithium niobate film and the electrode configuration, the mass sensitivity of the biosensor could reach up to 74,000 Hz/(ng/cm2), and the maximum value of figure of merit (FOM) was 5.52 × 107, which shows great potential for pushing the performance boundaries of gravimetric-sensitive acoustic biosensors.

Introduction: Carnitine–acylcarnitine translocase deficiency (CACTD) is a rare and life-threatening autosomal recessive disorder of mitochondrial fatty acid oxidation caused by variation of the Solute carrier family 25 member 20 (SLC25A20) gene. Carnitine–acylcarnitine translocase is one of the crucial transport proteins in the oxidation process of mitochondrial fatty acids. In Asia, the c.199-10T>G splice site variation is the most frequently reported variant of SLC25A20. Patients with CACTD with c.199-10T>G variation usually present with a severe clinical phenotype.Materials and Methods: Herein, we report a neonatal case of late-onset CACTD in mainland China. Symptoms emerged 61 days after birth; the patient presented with a severe metabolic crisis, and her clinical condition rapidly deteriorated, and she died of respiratory insufficiency and cardiac arrest at 61 days. We present the clinical and biochemical features of this patient and briefly review previously reported CACTD cases with c.199-10T>G variation.Results: Acylcarnitine profiling by tandem mass spectrometry and high-throughput sequencing revealed that our patient was homozygous for the c.199-10T>G variation, confirming the diagnosis of CACTD. Histopathologic analysis of the liver by Prussian blue staining showed focal iron deposition in hepatocytes, and electron microscopy analysis revealed a large number of lipid droplet vacuoles in diffusely distributed hepatocytes.Conclusion: The development of CACTD in our patient 61 days after birth is the latest reported onset for CACTD with SLC25A20 c.199-10T>G variation. Early recognition of symptoms and timely and appropriate treatment are critical for improving the outcome of this highly lethal disorder. Death from late-onset CACTD may be caused by the accumulation of long-chain fatty acids as well as iron deposition in the heart leading to heart failure.

Bronchopulmonary dysplasia (BPD) is a complex disorder resulting from interactions between genes and the environment. The accurate molecular etiology of BPD remains largely unclear. This study aimed to identify key BPD-associated genes and pathways functionally enriched using weighted gene co-expression network analysis (WGCNA). We analyzed microarray data of 62 pre-term patients with BPD and 38 pre-term patients without BPD from Gene Expression Omnibus (GEO). WGCNA was used to construct a gene expression network, and genes were classified into definite modules. In addition, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses of BPD-related hub genes were performed. Firstly, we constructed a weighted gene co-expression network, and genes were divided into 10 modules. Among the modules, the yellow module was related to BPD progression and severity and included the following hub genes: MMP25, MMP9, SIRPA, CKAP4, SLCO4C1, and SLC2A3; and the red module included some co-expression molecules that displayed a continuous decline in expression with BPD progression and included the following hub genes: LEF1, ITK, CD6, RASGRP1, IL7R, SKAP1, CD3E, and ICOS. GO and KEGG analyses showed that high expression of inflammatory response-related genes and low expression of T cell receptor activation-related genes are significantly correlated with BPD progression. The present WGCNA-based study thus provides an overall perspective of BPD and lays the foundation for identifying potential pathways and hub genes that contribute to the development of BPD.

A resonator with an appropriate electromechanical coupling coefficient (Kt2) is crucial for filter applications in radio communication. In this paper, we present an effective method to tune the Kt2 of resonators by introducing different materials into a lithium niobate (LiNbO3) piezoelectric matrix. The effective piezoelectric coefficients e33eff and e15eff of composite materials with four different introduced materials were calculated. The results show that the e15eff of SiO2/LiNbO3 composite piezoelectric material was mostly sensitive to an increase in the width of introduced SiO2 material. Simultaneously, the simulation of a laterally excited bulk wave resonator (XBAR) with SiO2/LiNbO3 composite material was also carried out to verify the change in the Kt2 originating from the variation in e15eff. The achievable n79 filter using the SiO2/LiNbO3 composite material demonstrates the promising prospects of tuning Kt2 by introducing different materials into a LiNbO3 piezoelectric matrix.

Radio frequency (RF) filters with multiple passbands can meet the needs of miniaturization and integration for 5G communications. This paper reports a dual-mode Lamb wave resonator (DLWR) and a dual-passband filter based on DLWRs. The DLWR consists of a piezoelectric film and two interdigital electrode (IDT) arrays with different thicknesses, which leads to the coexistence of two main modes in the resonator. The resonance frequencies of the two modes can be adjusted separately by changing the thicknesses of the IDTs, which greatly satisfies the requirements of the dual-passband filter. Four DLWRs with different electrode configurations are designed, and the influences of the periodic length and thicknesses of the IDTs on the performance of the DLWR are studied. When the thickness of the piezoelectric layer is 0.75 μm and the two thicknesses of the IDTs are 0.1 μm and 0.3 μm, the resonance frequency of the second main mode is 1.27 GHz higher than the resonance frequency of the first main mode in the DLWR. Furthermore, a dual-passband filter based on the proposed DLWRs is demonstrated with an insertion loss less than 1 dB and a band rejection of about 15 dB. Moreover, two passbands at 2.45 GHz and 3.88 GHz with bandwidths of 66 MHz and 112 MHz, respectively, are achieved. The presented DLWR shows a potential application that can be used to obtain RF filters with adjustable dual passbands.

As radio-frequency (RF) communication becomes more ubiquitous globally, film bulk acoustic resonators (FBAR) have attracted great attention for their superior performance. One of the key parameters of an FBAR, the effective electromechanical coupling coefficient (Keff2), has a great influence on the bandwidth of RF filters. In this work, we propose a feasible method to tune the Keff2 of the FBAR by etching the piezoelectric material to form a trench around the active area of the FBAR. The influence of the position of the etching trench on the Keff2 of the FBAR was investigated by 3D finite element modeling and experimental fabricating. Meanwhile, a theoretical electrical model was presented to test and verify the simulated and measured results. The Keff2 of the FBAR tended to be reduced when the distance between the edge of the top electrode and the edge of the trench was increased, but the Q value of the FBAR was not degraded. This work provides a new possibility for tuning the Keff2 of resonators to meet the requirements of different filter bandwidths.

Abstract Singular beams which possess helical phase wavefront or spatially inhomogeneous polarization provide new freedom for optical field manipulation. However, conventional schemes to produce the singular beams have difficulty in realizing the flexible switch between different singular beams. In this work, we have experimentally demonstrated the capability of dielectric metasurfaces to generate three types of singular beams and switch between them at working wavelength of 1550 nm. We have shown vortex beam and cylindrical vector beam generation with single metasurface and cylindrical vector vortex beam generation with two cascaded metasurfaces. Moreover, experimental demonstration on switching cylindrical vector beam into vortex beam has also been done by combining one quarter-wave plate and a Glan laser polarizer. The experimental results match well with the analysis from the Jones matrix calculations. The average conversion efficiency of cylindrical vector beam to vortex beam was estimated to be 47.7%, which was about 2.3% lower than the theoretical prediction.

Abstract A great proportion of nitrate taken up by plants is stored in vacuoles. Vacuolar nitrate accumulation and release is of great importance to nitrate reallocation and efficient utilization. However, how plants mediate nitrate efflux from vacuoles to cytoplasm is largely unknown. The current study identified NPF5.11, NPF5.12 and NPF5.16 as vacuolar nitrate efflux transporters in Arabidopsis. Histochemical analysis showed that NPF5.11, NPF5.12 and NPF5.16 were expressed preferentially in root pericycle cells and xylem parenchyma cells, and further analysis showed that these proteins were tonoplast-localized. Functional characterization using cRNA-injected Xenopus laevis oocytes showed that NPF5.11, NPF5.12 and NPF5.16 were low-affinity, pH-dependent nitrate uptake transporters. In npf5.11 npf5.12 npf5.16 triple mutant lines, more root-fed 15NO3 − was translocated to shoots compared to the wild type control. In the NPF5.12 overexpression lines, proportionally less nitrate was maintained in roots. These data together suggested that NPF5.11, NPF5.12 and NPF5.16 might function to uptake nitrate from vacuoles into cytosol, thus serving as important players to modulate nitrate allocation between roots and shoots.

Conventional plasmons in metals often suffer from high plasmonic loss in the optical range. Here, the authors report a distinct form of tunable correlated plasmons in Mott-like insulating Sr1−xNbO3+δfilms, with multiple plasmon frequencies and low loss in the visible-ultraviolet range.

Wide bandgap two-dimensional semiconductors are of paramount importance for developing van der Waals heterostructure electronics. This work reports the use of layer and strain engineering to introduce the feasibility of two-dimensional hexagonal (h)-AlN to fill the scientific and application gap. We show that such one- to five-layer h-AlN has an indirect bandgap, tunable from 2.9 eV for a monolayer to ∼3.5 eV for multilayer structures, along with isotropic effective masses and carrier mobilities between zigzag and armchair directions. With an increase in the layer number to bulk AlN, the bandgap will experience a transition from an indirect gap to direct gap. Surprisingly, high room-temperature mobilities of electrons and holes (of the order of 1000 cm2 V−1 s−1) in a relaxed monolayer h-AlN system and widely adjustable effective masses and carrier mobilities in a different layer h-AlN are observed. In the presence of strain engineering, the bandgap decreases obviously with an increase in tensile strain; meanwhile, the isotropy and value of effective mass or carrier mobility in monolayer h-AlN can also be modulated effectively; the hole mobilities in the armchair direction, especially, will be enhanced dramatically. With a tunable bandgap, high carrier mobilities, and modifiable isotropy, our results indicate that few-layer h-AlN has potential applications in future mechano-electronic devices.

Abstract Background Methylmalonic acidemia (MMA) is an autosomal recessive genetic disorder involving the metabolism of organic acids. Methods Here, we report the case of a patient who developed acute metabolic crisis after vaccination and was diagnosed with cblA type MMA after hospitalization. Results Further examination revealed a homozygous pathogenic variant in the MMAA gene that caused the disease in the patient but did not conform to Mendelian inheritance. Using chromosomal microarray analysis, maternal uniparental disomy (UPD) was found on chromosome 4q26‐q35.2 of the patient. The MMAA gene of the patient was inherited only from the mother and carried the same pathogenic variant on both alleles of chromosome 4. MMAA gene expression levels in whole blood were detected by real‐time PCR. Conclusion The nonsense pathogenic variant, NM_172250.2:c.742C>T (p.Gln248*), carried by the patient leads to a premature termination of transcription of the gene, thereby resulting in partial loss of protein function while retaining some others. Segmental UPD 4 is rare, and to our knowledge, has not been reported previously.

Circadian clocks control daily rhythms in behavior and physiology. In Drosophila, the small ventral lateral neurons (sLNvs) expressing PIGMENT DISPERSING FACTOR (PDF) are the master pacemaker neurons generating locomotor rhythms. Despite the importance of sLNvs and PDF in circadian behavior, little is known about factors that control sLNvs maintenance and PDF accumulation. Here, we identify the Drosophila SWI2/SNF2 protein DOMINO (DOM) as a key regulator of circadian behavior. Depletion of DOM in circadian neurons eliminates morning anticipatory activity under light dark cycle and impairs behavioral rhythmicity in constant darkness. Interestingly, the two major splice variants of DOM, DOM-A and DOM-B have distinct circadian functions. DOM-A depletion mainly leads to arrhythmic behavior, while DOM-B knockdown lengthens circadian period without affecting the circadian rhythmicity. Both DOM-A and DOM-B bind to the promoter regions of key pacemaker genes period and timeless, and regulate their protein expression. However, we identify that only DOM-A is required for the maintenance of sLNvs and transcription of pdf. Lastly, constitutive activation of PDF-receptor signaling rescued the arrhythmia and period lengthening of DOM downregulation. Taken together, our findings reveal that two splice variants of DOM play distinct roles in circadian rhythms through regulating abundance of pacemaker proteins and sLNvs maintenance.

Beams carrying orbital angular momentum (OAM) are very helpful in enhancing the information carrying capacity in free-space optical communications. However, atmospheric turbulence and energy attenuation will seriously affect communication quality and signal transmissions. Here, a novel coherent separation detection technology for OAM mode division multiplexing is proposed, and numerical simulation work is conducted. With the proposed structure, two light beams with different OAM states, each encoded with 16-quadrature-amplitude modulation orthogonal frequency-modulated (QAM-OFDM) signals, can be demultiplexed and allow two orders of magnitude bit error rate (BER) lower than direct separation detection. Moreover, we show the scalability of multiplexing four OAM beams, achieving a 20 m free-space transmission with BER below 3.8 × 10–3 for all channels at signal-noise ratio (SNR) 18 dB. Our results show that coherent separation detection has excellent antinoise performance and can effectively extend the communication distance. It also paves the way for entirely new coherent optical OAM communications.

Microelectromechanical (MEMS) piezoelectric accelerometers are diversely used in consumer electronics and handheld devices due to their low power consumption as well as simple reading circuit and good dynamic performance. In this paper, a tri-axial piezoelectric accelerometer with folded beams is presented. The four beam suspensions are located at two sides of the mass aligned with edges of the mass, and the thickness of the beams is the same as the thickness of the mass block. In order to realize the multi-axis detection, a total of 16 sensing elements are distributed at the end of the folded beams. The structural deformations, stress distribution, and output characteristics due to the acceleration in x-, y-, and z-axis directions are theoretically analyzed and simulated. The proposed accelerometer is fabricated by MEMS processes to form Mo/AlN/ScAlN/Mo piezoelectric stacks as the sensing layer. Experiments show that the charge sensitivity along the x-, y-, and z-axes could reach up to ~1.07 pC/g, ~0.66 pC/g, and ~3.35 pC/g. The new structure can provide inspiration for the design of tri-axial piezoelectric accelerometers with great sensitivity and linearity.

With the rapid commercialization of fifth generation (5G) technology in the world, the market demand for radio frequency (RF) filters continues to grow. Acoustic wave technology has been attracting great attention as one of the effective solutions for achieving high-performance RF filter operations while offering low cost and small device size. Compared with surface acoustic wave (SAW) resonators, bulk acoustic wave (BAW) resonators have more potential in fabricating high- quality RF filters because of their lower insertion loss and better selectivity in the middle and high frequency bands above 2.5 GHz. Here, we provide a comprehensive review about BAW resonator researches, including materials, structure designs, and characteristics. The basic principles and details of recently proposed BAW resonators are carefully investigated. The materials of poly-crystalline aluminum nitride (AlN), single crystal AlN, doped AlN, and electrode are also analyzed and compared. Common approaches to enhance the performance of BAW resonators, suppression of spurious mode, low temperature sensitivity, and tuning ability are introduced with discussions and suggestions for further improvement. Finally, by looking into the challenges of high frequency, wide bandwidth, miniaturization, and high power level, we provide clues to specific materials, structure designs, and RF integration technologies for BAW resonators.

Regional collision risk identification and prediction is important for traffic surveillance in maritime transportation. This study proposes a framework of real-time prediction for regional collision risk by combining Density-Based Spatial Clustering of Applications with Noise (DBSCAN) technique, Shapley value method and Recurrent Neural Network (RNN). Firstly, the DBSCAN technique is applied to cluster vessels in specific sea area. Then the regional collision risk is quantified by calculating the contribution of each vessel and each cluster with Shapley value method. Afterwards, the optimized RNN method is employed to predict the regional collision risk of specific seas in short time. As a result, the framework is able to determine and forecast the regional collision risk precisely. At last, a case study is carried out with actual Automatic Identification System (AIS) data, the results show that the proposed framework is an effective tool for regional collision risk identification and prediction.

Magnetotactic bacteria (MTB) are a diverse group of microorganisms capable of using geomagnetic fields for navigation. This magnetotactic behavior can help microorganisms move toward favorable habitats for optimal growth and reproduction. A comprehensive understanding of the magnetotactic mechanism at molecular levels requires highly efficient genomic editing tools, which remain underdeveloped in MTB. Here, we adapted an engineered CRISPR-Cas9 system for efficient inactivation of genes in a widely used MTB model strain, Magnetospirillum magneticum AMB-1. By combining a nuclease-deficient Cas9 (dCas9) and single-guide RNA (sgRNA), a CRISPR interference system was successfully developed to repress amb0994 expression. Furthermore, we constructed an in-frame deletion mutant of amb0994 by developing a CRISPR-Cas9 system. This mutant produces normal magnetosomes; however, its response to abrupt magnetic field reversals is faster than wild-type strain. This behavioral difference is probably a consequence of altered flagella function, as suggested with our dynamics simulation study by modeling M. magneticum AMB-1 cell as an ellipsoid. These data indicate that, Amb0994 is involved in the cellular response to magnetic torque changes via controlling flagella. In summary, this study, besides contributing to a better understanding of magnetotaxis mechanism, demonstrated the CRISPR-(d)Cas9 system as a useful genetic tool for efficient genome editing in MTB.