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Radio frequency (RF) noise can severely degrade the performance of electronic circuits and wireless systems. This article proposes an analytical method to evaluate the spectrum of RF noise caused by multicarrier multipactor discharge. First, a simplified model is developed to analyze the electric current characteristics of the resonant multicarrier multipactor discharge. Then, an analytical formula for the spectrum of the resonant multicarrier multipactor discharge is derived. Finally, the theoretical method is evaluated for dual-carrier operation inside a silver plated rectangular waveguide. Simulation results coincided well with theoretical findings show that the proposed method is encouraging.

What is known about this topic? The emerging H5Ny lineages of the avian influenza virus (AIV) with genomic reassortments have posed a continuous threat to animals and human beings. Since the first case of avian influenza A (H5N6) virus infection in 2014, the World Health Organization has reported a total of 38 cases by August 6, 2021. What is added by this report? A total of 5 new cases of H5N6 that occurred from May 2021 to July 2021 in Sichuan Province, China were reported in this study. Epidemiological and laboratory information of the five cases were investigated. The genomic analysis of the H5N6 genomes showed the features of AIV genomic reassortments and key residue substitutions. What are the implications for public health practice? The emergence of human cases infected by AIV H5Ny lineages through time demonstrates a risk of the persistence and evolution of the virus to trigger sporadic outbreaks and even pandemics, which need continuous surveillance.

We evaluated the cryoprotective effects of methanol on zebrafish sperm at different concentrations, exposure times, and stages during cryopreservation. Samples were collected by crushing of dissect...

Visible Light Communication (VLC) is becoming a promising technology of wireless communication, due to high data rate, low cost, and immunity to Radio Frequency (RF) interference. However, the VLC systems often suffer from service disruptions because of the limited coverage of light. Therefore, the heterogeneous networks of VLC and WiFi are proposed to achieve high-speed indoor communication and seamless coverage. This paper investigates an efficient heterogeneous network resource management algorithm, which is not only significant to integrate the current network resources but also has practical significance to improve the performance of heterogeneous networks. We establish a distributed joint resource management system model and propose two kinds of resource management allocation strategies to allocate bandwidth among the users with maximum fairness. The simulation results show the feasibility of the heterogeneous network and the effectiveness of the algorithm.

The mechanism of the passive intermodulation (PIM) distortion caused by the loose contact in coaxial connectors is of great importance in wireless communication systems. This paper focuses on the effect of the additional impedance on PIM levels in coaxial connectors. First, the additional impedance and PIM levels of the loose contact coaxial connectors are measured. Then, the S-parameters and the additional impedance with three different loose contact cases are simulated. Finally, a modified coaxial connector with different values of conductive tapes is designed to verify the additional impedance impacts on the PIM level. It is shown that the increase of the additional impedance of the metal–metal loose contact will lead to the deterioration of PIM levels in the coaxial connector.

This paper proposes a new method to comprehensively predict the passive intermodulation (PIM) distortion in loose contact coaxial connectors by the time-domain reflectometry (TDR) test. The proposed approach treats the insulating film current and the electrothermal (ET) coupling as PIM sources. An ET coupling model is introduced to analyze the generating process of the PIM caused by the ET coupling in the loose contact coaxial connectors. The simulation and measurement results show good agreement. The proposed method is a cost-effective approach for the evaluation of the PIM distortion, because it uses a common TDR method to replace professional PIM test instruments. The proposed method can also be extended to all the loose metallic contact cases.

The goal of this study was to investigate whether supplementation of cryoprotective medium with catalase (CAT), an antioxidation enzyme, is efficient for zebrafish sperm cryopreservation from the viewpoint of high-throughput genetic repository operations. Three cryoprotectants (10%, v/v), dimethylacetamide (DMA), dimethylformamide (DMF), and methanol were used. The objectives were to evaluate the effects of CAT on sperm motility, plasma membrane integrity, and concentration: 1) fresh sperm at equilibration up to 60 min; 2) post-thaw sperm after cooling at 10, 20, and 40 °C/min), and 3) post-thaw fertilization and embryo survival rates. Catalase addition did not improve sperm motility, regardless of the cryoprotectants added. After 10-min exposure to DMA and methanol, membrane integrity was significantly decreased (70-75%) compared to controls. With catalase, sperm cells were maintained membrane integrity and after 50 min equilibration, cell concentrations were maintained with CAT compared to cryoprotectant-only test groups. However, after cryopreservation and thawing, CAT did not affect the outcome of motility, membrane integrity, cell concentration, fertilization, or embryo survival assays. Analysis of cooling rates also indicated that CAT did not affect 3-hpf fertilization or 24-hpf survival rates. Overall, addition of CAT could provide some protection of sperm from oxidative stress before freezing, but not after thawing. We propose that decisions concerning routine use of CAT for repositories, especially those handling tens of thousands of frozen samples per year, would depend on whether efficient high-throughput operation, or specific research questions are programmatic goals.

Objectives: To explore and understand the SARS-CoV-2 seroprevalence of convalescents, the association between antibody levels and demographic factors, and the seroepidemiology of convalescents of COVID-19 till March 2021.Methods: We recruited 517 voluntary COVID-19 convalescents in Sichuan Province and collected 1,707 serum samples till March 2021. Then we reported the seroprevalence and analyzed the associated factors.Results: Recent travel history was associated with IgM levels. Convalescents who had recent travel history were less likely to be IgM antibody negative [OR = 0.232, 95% CI: (0.128, 0.420)]. Asymptomatic cases had, approximately, twice the odds of being IgM antibody negative compared with symptomatic cases [OR = 2.583, 95% CI: (1.554, 4.293)]. Participants without symptoms were less likely to be IgG seronegative than those with symptoms [OR = 0.511, 95% CI: (0.293, 0.891)]. Convalescents aged 40–59 were less likely to be IgG seronegative than those aged below 20 [OR = 0.364, 95% CI: (0.138, 0.959)]. The duration of positive IgM antibodies persisted 365 days while the IgG persisted more than 399 days.Conclusions: Our findings suggested that recent travel history might be associated with the antibody levels of IgM, while age could be associated with the antibody levels of IgG. Infection type could be associated with both antibody levels of IgM and IgG that declined quicker in asymptomatic cases.

Fibrinogen-related proteins (FREPs) are distributed universally in vertebrates and invertebrates. These proteins contain fibrinogen-like (FBG) domains in their C-terminal region and involve in immune responses and other aspects of physiology in invertebrates. In this study, 54 proteins that contain FBG domains or a fibrinogen_c domain were identified in Haliotis discus hannai. Comparatively, 88 and 63 FREPs were identified from the genomes of H. rufescens and H. laevigata. Most FREPs of abalones had a conserved motif containing a bound calcium ion site and a second conserved motif containing a polymerization pocket site. By sequence analysis, 394 SNPs and 11 Indels were identified in 20 FREP genes of the whole genome of H. discus hannai; 992 SNPs and 42 Indels were found in 64 FREPs of H. rufescens, and 192 SNPs and 12 Indels were found in 21 FREPs of H. laevigata. Among these SNPs, 92 missense mutation sites were identified in 26 FREP genes of H. rufescens, and 12 were identified in 8 FREP genes of H. laevigata. Due to the poor genomic integrity, annotations of the SNPs or Indels in H. discus hannai did not yield missense mutant sites. FREP genes with polymorphisms were ubiquitously expressed in all the tested tissues; however, the expression is lowest in the hemolymph. In response to Vibrio parahemolyticus infection, expression of FREP genes was significantly upregulated at different exposure times in gills, hepatopancreas, and hemolymph in H. discus hannai. Overall, this study documented the FREP genes of abalones and shed light on the role of FREPs in the innate immune system of these aquaculture species for the prevention and control of diseases.

ObjectivesTo understand SARS-CoV-2 seroprevalence of convalescents and assess their the immunity. Furthermore, we intend to explore the association between antibody levels and with demographic factors.Methods177 COVID-19 convalescents in Sichuan Province were voluntarily participated in our study. 363 serum samples were collected from June, 2020 to November, 2020. Duration of seroprevelance in these convalescents and their demographic characteristics were described, and the risk factors to antibody levels were analysed.ResultsMen had more than twice the odds of having IgM antibody positive compared with women (OR=2.419, 95% CI:[1.232, 4.751]). Participants without symptoms were nearly 0.5 times IgG seropositive than those with symptoms (OR=0.455, 95% CI: [0.220, 0.940]). People aged≥60 years were nearly 3 times IgG seropositive than those who aged < 20 years (OR=2.986, 95% CI: [1.058, 8.432]). Seroprevalence in asymptomatic declined quicker than symptomatic.ConclusionsAge and gender may affect the antibody levels and seroprevalence. Asymptomatic appeared more easier to turn to seronegative than symptomatic.

We investigated the effect of CMC dosage on dispersibility and sedimentation of FeS, and the effects of initial Cr(VI) concentrations, reaction temperatures and initial pH values on the Cr(VI) removal by Nano-FeS and CMC-FeS through experiments. At the same time, the migration performance and deposition of Nano-FeS and CMC-FeS under different conditions were investigated. The results showed that: Nano-FeS aggregated to floc and precipitated. The 2.4% CMC-FeS had good dispersibility and anti-settling capacity. With the initial concentration of Cr(VI) increased from 10 to 50 mg L

A critical challenge for the practical use of the layered O3-type binary nickel manganese oxides for sodium-ion batteries is the poor structural stability during extended cycling. The approaches of constructing O3/P2 hybrid composites can partially improve the cycling stability, but general approaches sacrifice the advantages of high capacity and low cost of the O3-type cathodes due to excessive sodium deficiency and lithium substitution. Here, we rationally design a serial of novel O3-majority hybrid Na0.9-xNi0.45Mn0.55O2 (x = 0.02, 0.04 and 0.08) cathodes, which exhibit high capacities while maintaining exceptional long-term stability. Particularly, the optimized O3/P2 Na0.88Ni0.45Mn0.55O2 composite delivers 106.7 mA h·g−1 with 71.1% capacity retention after 250 cycles at 1 C (1C = 150 mA g−1), the cyclability is 32% higher than that of the O3 Na0.9Ni0.45Mn0.55O2 cathode; and it also delivers a initial discharge capacity of 75.9 mA h·g−1, maintaining 72.4% capacity retention after 1000 cycles at 10 C. More importantly, the post-cycling analyses demonstrate O3/P2 hybrid phases successfully suppress the structural degradation of Na0.9Ni0.45Mn0.55O2 during battery operation. This study provides new perspectives in designing high performance cathodes for sodium-ion batteries.

Accurate prediction of multipactor threshold is of great importance for the suppressing of passive intermodulation. Multicarrier multipactor, which is a secondary electron emission excited by multicarrier signals, is the main risk to the long-term reliability of microwave components. The prediction of the global threshold power is thus important in the design of microwave components. The traditional prediction of the global threshold power of multicarrier multipactor is based on the 20-gap-crossing rule (20GCR), but it is independent of the time distribution and ignores the influence of different materials of components. This paper proposes a global threshold prediction method of multicarrier multipactor with time distribution and material coefficients, namely the time-material prediction method (P20TM). It accumulates energy that exceeds the traditional threshold, which provides a basis for distinguishing multicarrier signals with different time distributions. The proposed method adopts an improved simulated annealing algorithm realizing the optimization of the multidimensional function. Simulation results show good agreements with theoretic results, which indicate the P20TM can achieve more accurate prediction than the 20GCR.

Loose contact coaxial connectors are significant sources of passive intermodulation (PIM) in high-power and high-frequency communication systems. In this paper, a circuit model is presented to analyze PIM distortion in loose contact coaxial connectors. First, the loose contact surface model is built to calculate metal–insulator–metal and metal–metal contact resistance; and a method of time-domain reflectometry is used to verify the additional impedance of the loose contact surface. Then, the loose contact current is investigated to drive the equivalent circuit model of loose contact coaxial connectors. Finally, a two-tone experimental verification is conducted to show that the PIM of a loose contact coaxial connector can be analyzed by this model.

The SARS-CoV-2 virus, the causative agent of COVID-19, is undergoing constant mutation. Here, we utilized an integrative approach combining epidemiology, virus genome sequencing, clinical phenotyping, and experimental validation to locate mutations of clinical importance. We identified 35 recurrent variants, some of which are associated with clinical phenotypes related to severity. One variant, containing a deletion in the Nsp1-coding region (Δ500-532), was found in more than 20% of our sequenced samples and associates with higher RT-PCR cycle thresholds and lower serum IFN-β levels of infected patients. Deletion variants in this locus were found in 37 countries worldwide, and viruses isolated from clinical samples or engineered by reverse genetics with related deletions in Nsp1 also induce lower IFN-β responses in infected Calu-3 cells. Taken together, our virologic surveillance characterizes recurrent genetic diversity and identified mutations in Nsp1 of biological and clinical importance, which collectively may aid molecular diagnostics and drug design., Graphical Abstract, Bringing together epidemiological, genetic, and clinical data, Lin et al. identify viral mutations that associate with clinical phenotypes. The 500-532 locus in the Nsp1 coding region is a deletion hotspot in the SARS-CoV-2 genome, and deletion variants lead to lower IFN-I response. Prevalence of 500-532 deletion variants is accumulating worldwide.

In this paper, a metasurface Terahertz absorber based on the fractal technology of a graphene geometry resonator to realize ultra-wideband, ultrathin, adjustable double-layer cross-fractal formation is introduced. This paper proposes a dynamically tuned graphene absorbing material. The structure is composed of one- to four-level-fractal graphene pattern layers, MgF2 layers and metal reflective layers to form a two-sided mirror of an asymmetric Fabry&ndash, Perot cavity. To confine the terahertz electromagnetic wave, four different fractals are integrated into a supercell, and the coupling and superposition of adjacent resonant cavities form a broadband high-absorption absorber. Using finite element-based full-wave electromagnetic simulation software to simulate the response frequency of 0.4&ndash, 2.0 THz, we found that the absorber achieves a broadband 1.26 THz range (absorption &gt, 80%) and a relative bandwidth of 106.8%. By adjusting the Fermi energy, it can realize free switching and expand to wider broadband terahertz absorption, by adjusting the polarization angle (&Phi, ) from 0 to 90&deg, to prove that the structure is not sensitive to polarization, the absorber provides a 60&deg, large angle of incidence, polarization for TE and TM the absorption pattern remains basically the same. Compared with the previous work, our proposed structure uses fractal technology to expand the bandwidth and provide dynamic adjustable characteristics with great degrees of freedom. The appearance of the fractal structure reduces the difficulty of actual processing.

The goal of this study was to evaluate the efficacy of phenotypic traits and two genetic assays to distinguish between Mercenaria mercenaria, an important aquaculture species, and Mercenaria campechiensis, a conspecific species that is partially sympatric, but that has not been successfully farmed. The objectives were to evaluate (1) four established diagnostic phenotypic traits (lunule shape, thickness of concentric shell ridges, prominence of anterior side of the concentric ridges, and presence of purple nacre inside of the shells) to distinguish between species, (2) size polymorphism of PCR fragments from four genes [16S rRNA, 18S rRNA, Internal Transcribed Spacer genes (ITS1 and ITS2)], and (3) PCR-restriction fragment length polymorphism (RFLP) on three of these genes (16S, ITS1, and ITS2). Phenotypic traits correctly distinguished two geographically distant conspecific populations (two locations in Maine for M. mercenaria and in Bradenton, FL, for M. campechiensis); however, among all other locations, both species had overlapping phenotypic trait values. Although PCR fragments were obtained for all genes tested, size polymorphism was not identified between the two species. Restriction enzyme digestion of PCR fragments resulted in diagnostic fragments distinguishing the two species for 16S, ITS1, and ITS2. Although phenotypic scores failed to delineate between the two species in most locations, PCR-RFLP results failed to identify hybrids in wild or hatchery samples. Further investigation is needed to apply the PCR-RFLP assays on known hybrid offspring from crosses of M. mercenaria and M. campechiensis. Results have elucidated the difficulties in confidently detecting hybridization in quahogs; however, determining effective methods for species identification and hybrid detection will be important to address issues such as the prevalence and distribution of hybridization in aquaculture and in wild populations, and to determin the presence of M. campechiensis which are currently difficult to find.

In crustaceans, innate immunity serves as the frontline of defense against microbes. Alkaline phosphatases (ALPs) and acid phosphatases (ACPs) are essential enzymes that play a significant role in crustaceans' immune defenses. However, the function and transcriptional regulation of the alp and acp genes in the Scylla paramamosain, an important aquaculture species in China, have not been elucidated. In this study, the full-length cDNAs of Spalp and Spacp were identified, which consist of 2,718 bp and 3,768 bp, encoding 579 and 452 amino acids, respectively. Multiple sequence alignment and phylogenetic analysis showed that these two genes were conserved among different species and shared high homology with crustaceans. The mRNA expression of Spalp and Spacp were examined in eight tested tissues, with the highest levels in the hepatopancreas. The 5'-flanking regions of Spalp and Spacp were cloned and sequenced. The core promoter region of the Spalp and Spacp was -39 bp∼+8 bp and -39 bp∼+10 bp, respectively. Potential binding sequences for SOX-2, c-fos, SP1, NF-κB, GATA-1, YY1, and AP-1 transcription factors were found in the 5’-flanking regions of Spalp and Spacp. The NF-κB binding site located between -1,223 bp and -972 bp in Spalp while SP1 and AP-1 binding sites located between -1,249 bp and -514 bp in Spacp. Mutation analysis confirmed that NF-κB negatively regulated the expression of Spalp gene, and SP1 and AP-1 positively regulated Spacp gene expression. These results provide us with essential information to elucidate the function of the Spalp and Spacp in S. paramamosain. This study is the first one to analyze the activity of Spalp and Spacp promoters.

This review is focused on the status and summary of larval cryopreservation in aquaculture mollusks. A total of 26 publications were identified addressing 14 molluscan bivalve species. Most studies were conducted on trochophores and D-larvae, a few studies were on umbo larvae, and no study was found on pediveligers. Based on the post-thaw viability, there is no general conclusion about the best larval stage for cryopreservation. The research topics of most publications focused on developing or improving cryopreservation protocols through exploring one or more vital factors of the cryopreservation procedure. The most dominant cryoprotectant agents (CPAs) used for molluscan larval cryopreservation were dimethyl sulfoxide (DMSO), propylene glycol (PG), and ethylene glycol (EG) at final concentrations of 5–15%. Non-permeable CPAs, such as glucose, fructose, sucrose, trehalose, and polyvinylpyrrolidone (PVP), were dominantly used as additives. Most cooling processes started from 0 °C, 4 °C, or larval culture temperature to −10 °C or − 12 °C at −1 °C/ min and holding at this temperature for 5–15 min with or without “seeding”, and then continued to cool to around −35 °C at −0.3 to −2.5 °C/ min (mostly at −0.5 and − 1 °C/ min) followed by a 5–10 min holding period. All frozen samples were then transferred into liquid nitrogen (−196 °C) for long-term storage. Evaluation of post-thaw viability was reported over a wide range of parameters with no standard criteria, for example, motile post-thaw larvae were considered alive but no definition of swimming velocity. A sharp decrease of survival was often reported after a period of culture although immediate post-thaw survivals were reported high in several studies. Overall, no general optimal protocol could be concluded. Post-thaw larvae were reported to survive beyond metamorphosis in Pacific oysters and even to the adult stage and reproduced successfully after 3 years of culture, indicating the promising future of this technology. Till now, no study has been reported on germplasm cryobanking by use of molluscan larval cryopreservation. Pathways and aspects for promoting molluscan larval cryopreservation technology for germplasm repository establishment and commercial seed production were discussed.

A method of coding patterns is proposed to achieve flexible control of absorption response at terahertz frequencies. The designed absorber consists of an Au-graphene pattern layer, a SiO2 layer and a metal reflective layer. Among them, we use concentrical circle structure to achieve broadband absorption, and adjust graphene&rsquo, s Fermi level to achieve tunable absorption. In addition, we propose an encoding method that can achieve flexible control of the absorption response at the terahertz frequency based on the external voltage applied on the graphene membrane, thereby having a programmable function. We also use COMSOL to simulate the electric field distribution diagram to explain the underlying physical mechanism. The programmable broadband adjustable absorber proposed in this paper has potential application prospects in the fields of optical equipment, information transmission, digital coding and artificial intelligence (AI).

We evaluated the cryoprotective effects of methanol on zebrafish sperm at different concentrations, exposure times, and stages during cryopreservation. Samples were collected by crushing of dissected testes or abdominal stripping. After exposure to 0%, 2%, 5%, 8%, and 10% methanol for 0–11 min, fresh sperm (1 × 10(6) cells/mL) did not show changes in plasma membrane integrity (measured by flow cytometer), but cell size changes (light scatter) were observed after exposure to 8% or 10%. After exposure for 0–60 min, fresh sperm (1 × 10(8) cells/mL) did not show significant changes in survival or membrane integrity. Sperm cryopreserved in 5%, 8%, and 10% methanol showed high post-thaw survival, in 5% and 8% showed high post-thaw motility, and in 5% showed highest post-thaw membrane integrity compared to other concentrations between 0% and 10%. Within 0–60 min after thawing, no significant differences in cell survival and membrane integrity were found for any concentration (p ≥ 0.269). Comparison of 5% and 8% methanol for dissected testes (n = 20) revealed no difference in post-thaw motility, membrane integrity, cell survival, fertilization, or hatching, embryo viability; for stripped sperm (n = 10), no differences were observed in post-thaw membrane integrity, fertilization, and embryo viability, however, higher motility and survival were detected in 5% than in 8% methanol. Thus, a concentration of 5% methanol seems most suitable for cryopreserving zebrafish sperm based on post-thaw survival and motility.

COVID-19 is a highly contagious disease caused by a novel coronavirus SARS-CoV-2. The interaction between SARS-CoV-2 spike protein and the host cell surface receptor ACE2 is responsible for mediating SARS-CoV-2 infection. By analyzing the spike-hACE2 interacting surface, we predicted many hot spot residues that make major contributions to the binding affinity. Mutations on most of these residues are likely to be deleterious, leading to less infectious virus strains that may suffer from negative selection. Meanwhile, several residues with mostly advantageous mutations have been predicted. It is more probable that mutations on these residues increase the transmission ability of the virus by enhancing spike-hACE2 interaction. So far, only a limited number of mutations has been reported in this region. However, the list of hot spot residues with predicted downstream effects from this study can still serve as a tracking list for SARS-CoV-2 evolution studies. Coincidentally, one advantageous mutation, p.476G>S, started to surge in the last couple of weeks based on the data submitted to the public domain, indicating that virus strains with increased transmission ability may have already spread.

Due to increased temperatures and aquaculture density, thermal and hypoxia stresses have become serious problems for the aquaculture of abalone Haliotis diversicolor. Stresses lead to immunosuppression, which can cause severe negative impacts on aquaculture farms. To study the mechanism of immunosuppression after hypoxia stress and bacterial challenge, transcriptomes of H. diversicolor hemocytes involved in immunity were profiled. A total of 307,395,572 clean reads were generated and assembled into 99,774 unigenes. KEGG analysis indicated that 225 unigenes with immunologic function were mapped into immune-related pathways. Expression of 41 unigenes measured by quantitative real-time PCR (qRT-PCR) showed consistent results with that of transcriptome analysis. When exposure challenge of Vibrio parahaemolyticus, it is indicated that the PI3K-AKT, MAPK, NF-κB and P53 signal pathways were involved in the hypoxia-induced immunosuppression of H. diversicolor. Furthermore, when the AKT gene (HdAKT) was inhibited by double-stranded RNA (dsRNA), expression levels of HdAKT was lower than the blank and control group in hemocytes at 4 h, 12 h and 24 h (p

Mitochondrial transcription termination factors (mTERFs) regulate the expression of mitochondrial genes and are closely related to the function of the mitochondrion and chloroplast. In this study, the mTERF gene family in capsicum (Capsicum annuum L.) was identified and characterized through genomic and bioinformatic analyses. Capsicum was found to possess at least 35 mTERF genes (CamTERFs), which were divided into eight major groups following phylogenetic analysis. Analysis of CamTERF promoters revealed the presence of many cis-elements related to the regulation of cellular respiration and photosynthesis. In addition, CamTERF promoters contained cis-elements related to phytohormone regulation and stress responses. Differentially expressed genes in different tissues and developmental phases were identified using RNA-seq data, which revealed that CamTERFs exhibit various expression and co-expression patterns. Gene ontology (GO) annotations associated CamTERFs primarily with mitochondrion and chloroplast function and composition. These results contribute towards understanding the role of mTERFs in capsicum growth, development, and stress responses. Moreover, our data assist in the identification of CamTERFs with important functions, which opens avenues for future studies.

Sperm cryopreservation is a highly efficient method for preserving genetic resources. It extends the reproductive period of males and significantly reduces costs normally associated with maintenance of live animal colonies. However, previous zebrafish (Danio rerio) cryopreservation methods have produced variable outcomes and low post-thaw fertilization rates. To improve post-thaw fertilization rates after cryopreservation, we developed a new extender and cryoprotective medium (CPM), introduced quality assessment (QA), determined the optimal cooling rate, and improved the post-thaw in vitro fertilization process. We found that the hypertonic extender E400 preserved motility of sperm held on ice for at least 6 h. We implemented QA by measuring sperm cell densities with a NanoDrop spectrophotometer and sperm motility with computer-assisted sperm analysis (CASA). We developed a CPM, RMMB, which contains raffinose, skim milk, methanol, and bicine buffer. Post-thaw motility indicated that the optimal cooling rate in two types of cryogenic vials was between 10 and 15°C/min. Test thaws from this method produced average motility of 20% ± 13% and an average post-thaw fertilization rate of 68% ± 16%.

In D2D communication, physically adjacent users can directly establish connections without transmitting through base station, which can improve the network performance. The cellular D2D caching technology can offload part of the traffic of the base station and effectively alleviate the data transmission pressure of the base station. However, there is no research on cache mechanism in cellular D2D network that consider the collaboration willingness of equipment (UE). Therefore, the cooperative willingness aware collaborative caching mechanism towards cellular D2D communication (CWCM) is proposed. First, a D2D UE cache capability estimation method is proposed, which comprehensively considers the cache space occupied by the local cache content and the actual cache space setting of the UE to estimate the cache capability of the UE. Second, a D2D UE service relationship perception method is presented in which the content cache and the content discard records are used to comprehensively consider the cooperative and non-cooperative behavior to sense the service relationship between D2D UEs. Third, a collaborative willingness awareness caching mechanism is designed by considering the cache capability of the UE and the service relationship between the UEs. Simulation results show that the proposed CWCM can greatly improve the cache hit rate, largely reduce the transmission energy consumption, and average delay.

The expansion of the global macroalgal aquaculture and climate change creates the need for germplasm preservation of valuable aquaculture strains and maintenance of natural biodiversity. Compared to the large number of studies in fish and shellfish species, relative few studies have been conducted on the macroalgal germplasm cryopreservation. The first cryopreservation of macroalgae to −75 °C was reported on Neopyropia tenera (formerly called Porphyra tenera) in 1964. To date, a total of 34 studies reported germplasm cryopreservation in 33 species, including Chlorophyta (7 species), Ochrophyta (14 species), and Rhodophyta (12 species). The goal of this review was to summarize the published studies on macroalgal germplasm cryopreservation, compare the reported protocols for the cryopreservation process, and identify the factors affecting post-thaw viability. Overall, macroalgal germplasm cryopreservation included haploid or diploid thalli, spores, and gametes. Cryotubes (1.5-ml or 2-ml) have been widely used to package germplasm samples for cooling and storage in most studies, and the 0.5-ml straws and 5-ml cryotubes have been used in several studies. Two approaches (programmable controlled cooling and vitrification) were employed for macroalgal germplasm cryopreservation. A two-step programmable controlled cooling (e.g., from initial culture temperature to a frozen temperature, such as −40 °C, and then directly plunging into liquid nitrogen at −196 °C) was determined to be an effective cooling strategy. Vitrification, a super rapid cooling for a sample to form non-crystalline amorphous solid, was applied on macroalgal germplasm cryopreservation with sample encapsulation and dehydration. Survival of post-thaw samples varied significantly in different studies. Based on research updates, recommendations are made for future research. It is expected that this review can serve as a foundation for future germplasm banking of macroalgae for aquaculture and biodiversity preservation.

Suppressing passive intermodulation distortion is an important precondition to ensure the safety, stability, and economic operation of the mobile communication systems. It is also an important guarantee for promoting the co-construction and sharing of telecom infrastructure. The most fundamental approach to suppress the distortion is the study of mechanisms of passive intermodulation. In this paper, the mechanism of loose electrical contact is studied. First, the microcosmic characteristic of the metal surface is analyzed. Then, the electrical parameters such as impedance, current density in the loose contact surface are analyzed. Finally, the simulation and measurement are conducted. We conclude that the additional impedance and increased current density, which are caused by the loose electrical contact, are the direct factors for generating the passive intermodulation distortion.

RHEB (Ras Homolog Enriched in Brain) is a GTP-binding protein that is ubiquitously expressed in humans and other mammals. The protein is largely involved in the mechanistic target of rapamycin (mTOR) pathway, and regulates the cell cycle progression and growth. The goal of this study was to characterize the RHEB gene in the small abalone Haliotis diversicolor, and identify the responses of RHEB gene to stresses of hypoxia or/and thermal. The objectives were to: 1) clone the full-length cDNA RHEB gene in the H. diversicolor (HdRHEB); 2) quantify the expression of HdRHEB gene in tissues of haemocytes, mantle, kidney, gill, digestive tract, colleterial gland, and hepatopancreas by using RT-PCR, and 3) evaluate the responses of HdRHEB in gill and haemocyte to stresses of hypoxia (0.2mg/l00ml), thermal (31°C), and combination of hypoxia (0.4mg/l00ml) and thermal (30°C) at exposure time of 0, 4, 24, 96, and 192h. The full length cDNA of HdRHEB was 1044bp encoding a peptide of 182 amino acid residues. Expression of HdRHEB gene was detected in all of the 7 tissues and showed the highest in mantle (P0.05). Under hypoxia, expression of HdRHEB in gill increased significantly at 4h, 24h and 96h (P0.05), and that in haemocyte increased significantly at 24h, 96h and 192h (P0.05). Under thermal stress, expression of HdRHEB gene in gill decreased significantly at 4h and 24h, while expression in haemocyte decreased significantly all the time. Under thermal and hypoxia stresses, expression of HdRHEB gene in gill and haemocyte was up-regulated significantly at 24h and 96h (P0.05). The results in this study demonstrated for the first time that RHEB gene in abalones is able to response to stress stimuli of hypoxia or/and thermal.

Searching low-cost porous carbon is crucial for the future development of supercapacitors in a wide application range. In this paper, rice husk derived carbon (RHC) was prepared through direct carbonization of rice husk in a tube furnace without inlet of N2. RHC possesses relatively high pore volume, specific surface area and specific capacitance. The high specific surface area of RHC is attributed to the self-activation of rice husk by H2O, CO2 produced in the carbonization process. RHC was further treated by alkali etching to prepare a porous carbon (referred as RHPC). Owing to the removing of SiO2 in RHC, RHPC exhibits higher specific surface area and specific capacitance than RHC.

Sperm cryopreservation is an essential tool for long-term storage of genetic resources for aquaculture fishes. The goal of this study was to develop an efficient and streamlined protocol for high-throughput processing for sperm cryopreservation in Atlantic salmon, Salmo salar. The objectives were to evaluate: 1) osmolality of blood serum for determining extender osmolality; 2) effects of extenders for fresh sperm dilution and refrigerated storage; 3) effects of methanol and dimethyl sulfoxide (DMSO) on fresh sperm motility, and 4) motility and fertility after thawing. In this study, sperm samples were collected at a hatchery site in Canada, and shipped to a freezing site located 2200 miles (3550 km) away in the United States. Evaluation of three extenders indicated that Mounib solution was suitable for diluting dry sperm for sample processing. Ten percent of methanol or DMSO was less toxic to sperm cells than was 15% within 30 min. Further testing with methanol at 5, 10, and 15%, and sperm solution:extender dilutions (v:v) of 1:1, 1:3, 1:19 (at concentrations of ~5×107; 3×108, and 1×109 cells/mL) indicated that methanol at 5% and 10% showed less toxicity to fresh sperm within 1 hr at sperm: extender dilutions of 1:1 and 1:3. Post-thaw motility of sperm cryopreserved with 10% methanol was significantly higher than that with 10% DMSO, and fertility reflected those results (0-1% in DMSO vs. 38-55% in methanol). Further evaluation of sperm cryopreservation with 10 and 15% methanol at sperm dilution ratios of 1:1, 1:3, 1:19 indicated post-thaw motility in 10% methanol was significantly higher than that in 15% methanol, and post-thaw fertility in 10% methanol at 1:1 and 1:3 dilution ratios had fertilization rates similar to that of fresh sperm controls. Sperm samples from 12 males cryopreserved with 10% methanol showed male-to-male variation in post-thaw motility (0-36%). Overall, a simplified standard protocol was established for cryopreservation of shipped sperm of Atlantic salmon using extender without egg yolk and yielded satisfactory post-thaw motility and fertilization rates. This procedure can be readily adopted by aquaculture facilities to take advantage of high-throughput cryopreservation capabilities at remote service centers. Most importantly, this approach lays the groundwork for an alternative commercial model for commercial-scale production, quality control and development of industrial standards. Control of male variability and sperm quality remain important considerations for future work.

Music playlist recommendation is an important component in modern music streaming services, which is used for improving user experience by regularly pushing personalized music playlists based on users’ preferences. In this paper, we propose a novel music playlist recommendation problem, namely Personalized Music Playlist Recommendation (PMPR), which aims to provide a suitable playlist for a user by taking into account her long/short-term preferences and music contextual data. We propose a data-driven framework, which is comprised of two phases: user/music feature extraction and music playlist recommendation. In the first phase, we adopt a matrix factorization technique to obtain long-term features of users and songs, and utilize the Paragraph Vector (PV) approach, an advanced natural language processing technique, to capture music context features, which are the basis of the subsequent music playlist recommendation. In the second phase, we design two Attention-based Long Short-Term Memory (AB-LSTM) models, i.e., typical AB-LSTM model and Improved AB-LSTM (IAB-LSTM) model, to achieve the suitable personalized playlist recommendation. Finally, we conduct extensive experiments using a real-world dataset, verifying the practicability of our proposed methods.

The seasonality of individual influenza subtypes/lineages and the association of influenza epidemics with meteorological factors in the tropics/subtropics have not been well understood. The impact of the 2009 H1N1 pandemic on the prevalence of seasonal influenza virus remains to be explored. Using wavelet analysis, the periodicities of A/H3N2, seasonal A/H1N1, A/H1N1pdm09, Victoria and Yamagata were identified, respectively, in Panzhihua during 2006–2015. As a subtropical city in southwestern China, Panzhihua is the first industrial city in the upper reaches of the Yangtze River. The relationship between influenza epidemics and local climatic variables was examined based on regression models. The temporal distribution of influenza subtypes/lineages during the pre-pandemic (2006–2009), pandemic (2009) and post-pandemic (2010–2015) years was described and compared. A total of 6892 respiratory specimens were collected and 737 influenza viruses were isolated. A/H3N2 showed an annual cycle with a peak in summer–autumn, while A/H1N1pdm09, Victoria and Yamagata exhibited an annual cycle with a peak in winter–spring. Regression analyses demonstrated that relative humidity was positively associated with A/H3N2 activity while negatively associated with Victoria activity. Higher prevalence of A/H1N1pdm09 and Yamagata was driven by lower absolute humidity. The role of weather conditions in regulating influenza epidemics could be complicated since the diverse viral transmission modes and mechanism. Differences in seasonality and different associations with meteorological factors by influenza subtypes/lineages should be considered in epidemiological studies in the tropics/subtropics. The development of subtype- and lineage-specific prevention and control measures is of significant importance.

The development of the layered cathode material for sodium ion batteries are hindered by synthesis approaches. The sol-gel method is a promising way to prepare the cathodes due to the advantage of mixing the raw product at atomic or molecular level, while the selection criteria for complexing agents are still unclear. Herein, the Na0.9Ni0.45Mn0.55O2 cathode is successfully prepared via sol-gel method, by using sucrose, glucose, citric acid, and ethylene diamine tetra-acetic acid as the chelating agent, respectively. The effects of different chelating agents on the morphologies, structural and electrochemical properties are studied in detail. Electrochemical properties prove that the sample using citric acid shows the best electrochemical performance, delivering a capacity of 96 mAh g−1 and 48% retention after 300 cycles at 1C, and 59.6 mAh g−1 of capacity at 10 C rate, which are significantly higher than those of the other samples. XRD and HRTEM are conducted for the cycled electrodes, which demonstrate that the structure of the optimized sample maintains better phase stability and interfacial stability. This work is of considerable significance in understanding the selection criteria for the synthesis of layered cathode chelators for sodium-ion batteries by the sol-gel method.