ABSTRACT
Mass analysis in an ion trap is conventionally realized through time domain analysis of the ejected ion current collected from an electron multiplier (EM), in which the ion ejection time is found to have a correlation with the mass-to-charge (m/z) ratio of the ion. In this study, we investigated a new method for mass analysis by examining ion ejection signals in the frequency domain. Theoretical analysis and ion trajectory simulations show that ions of the same m/z ratio are ejected from an ion trap at regular intervals, producing a periodic pulsed signal on the EM. The period of this pulsed ejection signal is directly linked to the m/z values of the ions. To realize this method experimentally, a broadband preamplifier was built and integrated on a miniature ion trap mass spectrometer (the "Brick" series from Nier Inc.) to capture this pulsed ion ejection signal collected from the EM. Experimental results were in good agreement with theoretical and simulation analyses. This method has the potential to improve the mass resolution of an ion trap mass analyzer. As a proof-of-concept demonstration, a peak width of 0.1 Da at a m/z value of 281 was achieved in experiments.
ABSTRACT
This paper studies the dynamic response characteristics of the scanning angle in a liquid crystal cladding waveguide beam scanner. Based on liquid crystal dynamic theory, finite element analysis and vectorial refraction law, a dynamic response calculation model of scanning angle is constructed. The simulation results show that the dynamic responses of the scanning angle during the electric field-on and field-off processes are asymmetric, and exhibit "S"-shape and "L"-shape changing trends, respectively. In addition, by comparing with the bulk phase modulation response process of traditional liquid crystal devices, the intrinsic physical reason for the rapid light regulation of the liquid crystal cladding waveguide beam scanner is clarified to be that the liquid crystal close to the core layer has a faster rotation speed during the electric field-off process. Moreover, the liquid crystal cladding waveguide beam scanner is experimentally tested, and the experiment results are in good agreement with theoretical simulations.
ABSTRACT
Heterosis has been utilized in aquaculture for many years, yet its molecular basis remains elusive. Therefore, a comprehensive analysis of heterosis was conducted by comparing growth, digestion and biochemistry indices, as well as the intestinal gene expression profiles of Nile tilapia, blue tilapia and their hybrids. The results revealed that hybrid tilapia demonstrated an enhanced growth traits and elevated digestive enzyme activity compared to Nile and blue tilapia. Additionally, the hybrid tilapia displayed superior antioxidants and non-specific immune levels, with increased levels of catalase (CAT), alkaline phosphatase (AKP), acid phosphatase (ACP), glutathione (GSH), superoxide dismutase (SOD), total antioxidant capacity (TAOC), lysozyme, and immunoglobulin M (IgM) relative to Nile and blue tilapia. Moreover, 3392, 2470 and 1261 differentially expressed genes (DEGs) were identified in the intestinal tissues when comparing Nile tilapia to blue tilapia, hybrid tilapia to blue tilapia, and hybrid tilapia to Nile tilapia. Upon classifying the differentially expressed genes (DEGs), non-additively expressed DEGs accounted for 68.1 % of the total DEGs, with dominant and over-dominant expressed DEGs comprising 63.7 % and 4.4 % in the intestines, respectively. These non-additively expressed DEGs were primarily associated with metabolic, digestive, growth, and developmental pathways. This enrichment enhances our comprehension of the molecular underpinnings of growth heterosis in aquatic species.
Subject(s)
Hybrid Vigor , Tilapia , Animals , Hybrid Vigor/genetics , Tilapia/genetics , Tilapia/growth & development , Intestines , Hybridization, Genetic , Cichlids/genetics , Cichlids/growth & development , Transcriptome , Fish Proteins/genetics , Fish Proteins/metabolism , Gene Expression Profiling , Antioxidants/metabolismABSTRACT
Hybridization is a widely used breeding technique in fish species that enhances desirable traits in cultured species through heterosis. However, the mechanism by which hybrids alter gene expression to form heterosis remains unclear. In this study, a group of hybrid tilapia was used to elucidate heterosis through interspecies crossing. Specifically, p38 was analyzed to describe the regulation of gene expression variation in hybrid tilapia. Transcripts from the Nile tilapia allele were found to be significantly higher than those from the blue tilapia allele in hybrid individuals, indicating that the expression of p38 was dominated by Nile tilapia sub-genomic alleles. The study also found a compensatory interaction of cis- and trans-acting elements of the Nile tilapia and blue tilapia sub-genomes, inducing a non-additive expression of p38 in hybrids. Eight specific SNPs were identified in the p38 promoter regions of Nile tilapia and blue tilapia, and were found to be promoter differences leading to differences in gene expression efficiencies between parental alleles using a dual-luciferase reporter system. This study provides insights into the non-additive expression patterns of key functional genes in fish hybrids related to growth and immunity response.
ABSTRACT
BACKGROUND: Muscle occupies most of the fish body, promoting the proliferation of fish muscle fibers can facilitate rapid growth and increase the body weight of fish. Some studiesSeveral previous suggest that Myogenic regulatory factors (MRFs) play an important role in the growth of fish. OBJECTIVE: To investigate the association between the polymorphism of MRFs gene family and growth traits in Nile tilapia (Oreochromis niloticus), get more molecular markers for growth. METHODS: Amplified the Nile tilapia MRFs family gene, including Myogenic determination 1 (Myod1), Myogenic determination 2 (Myod2), Myogenin (Myog), Myogenic factor 5 (Myf5), and Myogenic factor 6 (Myf6), single nucleotide polymorphism (SNP) were screened by Sanger sequencing. RESULTS: A total of 16 SNP loci were screened, including six for Myf5, six for Myf6, one for Myog, one for Myod1 and two for Myod2. The growth traits were analyzed in relation to these 16 SNP loci, and the results indicated significant associations between all 16 SNP loci and the growth traits (P < 0.05). The linkage disequilibrium analysis revealed that D1 and D2 diplotypes of Myf5 gene, E1, E2, E3 and E4 of Myf6 gene, and F1 diplotype of Myod2 gene were significantly associated with superior growth traits. CONCLUSION: There were 6, 6, 1, 1 and 2 growth-related molecular markers in Myf5, Myf6, Myog, Myod1 and Myod2 genes, respectively, which could be applied to the breeding of Nile tilapia.
Subject(s)
Cichlids , Animals , Cichlids/genetics , Polymorphism, Single Nucleotide/genetics , Myogenic Regulatory Factors , Myogenic Regulatory Factor 5 , Body WeightABSTRACT
In miniature ion trap mass spectrometry, achieving a balance between isolation resolution and efficiency is a formidable challenge. The presence of absorption curves causes target ions to inadvertently absorb energy from AC signal components near their resonant frequencies. To mitigate this issue, SAM-SFM waveforms introduce a parameter known as the decreasing factor. Unlike SWIFT waveforms, SAM-SFM's spectral profile intentionally departs from a rectangular window, adopting an arch-shaped excitation window to minimize the impact on target ions and improve ion isolation efficiency. SAM-SFM waveforms have the advantage of low computational complexity, enabling real-time computation using an embedded FPGA technology. Regardless of any parameter changes, the FPGA can consistently guarantee waveform output within 1 µs. This not only enhances throughput but also eliminates the need for a PC in miniature mass spectrometry devices. The performance of SAM-SFM has been validated on an improved "Brick" miniature ion trap mass spectrometer. Comparative experiments with SWIFT waveforms confirm the lossless unit-mass isolation capabilities of SAM-SFM. This waveform has the capability to simultaneously isolate multiple target ions, even allowing for the lossless isolation of ions with lower abundance within isotopic clusters, albeit at the cost of requiring extended isolation durations.
ABSTRACT
We used cultured human conjunctival goblet cells to determine (i) whether the toxigenic S. aureus- induced activation of the epithelial goblet cells requires two signals to activate the NLRP3 inflammasome, (ii) if one signal is mediated by TLR1, TLR2, or TLR6, and (iii) if the S. aureus toxin α toxin is another signal for the activation of the inflammasome and secretion of mature IL-1ß. Cultured cells were incubated with siRNA to knock down the different TLRs. After stimulation with toxigenic S. aureus RN6390, pro-IL-1ß synthesis, caspase-1 activity, and mature IL-1ß secretion were measured. In a separate set of experiments, the cells were incubated with toxigenic S. aureus RN6390 or mutant S. aureus ALC837 that does not express α toxin with or without exogenous α toxin. A gentamicin protection assay was used to determine if intracellular bacteria were active. We conclude that α toxin from toxigenic S. aureus triggers two separate mechanisms required for the activation of the NLRP3 inflammasome and secretion of mature IL-1ß. In the first mechanism, α toxin secreted from internalized S. aureus produces a pore, allowing the internalized bacteria and associated pathogen-associated molecular patterns to interact with intracellular TLR2 and, to a lesser extent, TLR1. In the second mechanism, α toxin forms a pore in the plasma membrane, leading to an efflux of cytosolic K+ and influx of Ca2+. We conclude that α toxin by these two different mechanisms triggers the synthesis of pro-IL-1ß and NLRP3 components, activation of capase-1, and secretion of mature IL-1ß to defend against bacterial infection.
Subject(s)
Inflammasomes , NLR Family, Pyrin Domain-Containing 3 Protein , Humans , NLR Family, Pyrin Domain-Containing 3 Protein/genetics , Inflammasomes/metabolism , Toll-Like Receptor 2/metabolism , Staphylococcus aureus/metabolism , Goblet Cells , Toll-Like Receptor 1 , Caspase 1/metabolism , Interleukin-1beta/metabolismABSTRACT
In space gravitational wave detection missions, a drag-free system is used to keep the test mass (TM) free-falling in an ultralow-noise environment. Ground verification experiments should be carried out to clarify the shielding and compensating capabilities of the system for multiple stray force noises. A hybrid apparatus was designed and analyzed based on the traditional torsion pendulum, and a technique for enhancing the sensitivity of the torsion pendulum system by employing the differential wavefront sensing (DWS) optical readout was proposed. The readout resolution experiment was then carried out on an optical bench that was designed and established. The results indicate that the angular resolution of the DWS signal in optical readout mode can reach the level of 10 nrad/Hz1/2 over the full measurement band. Compared with the autocollimator, the sensitivity of the torsional pendulum is noticeably improved, and the background noise is expected to reach 4.5 × 10-15 Nm/Hz1/2@10 mHz. This method could also be applied to future upgrades of similar systems.
ABSTRACT
Tilapia is one of the most economically important freshwater fish farmed in China. Streptococcosis outbreaks have been extensively documented in farmed tilapia species. Hybrid tilapia (Oreochromis niloticus â × O. aureus â) exhibit greater disease resistance than Nile tilapia (O. niloticus) and blue tilapia (O. aureus). However, the molecular mechanism underlying the enhanced tolerance of hybrid tilapia is still poorly understood. In this study, comparative transcriptome analysis was performed to reveal the different tolerance mechanisms to Streptococcus agalactiae in the three tilapia lines. In total, 1982, 2355, and 2076 differentially expressed genes were identified at 48 h post-infection in hybrid tilapia, Nile tilapia, and blue tilapia, respectively. Functional enrichment analysis indicated that numerous metabolic and immune-related pathways were activated in all three tilapia lines. The differential expression of specific genes associated with phagosome, focal adhesion, cytokine-cytokine receptor interaction, and toll-like receptor signaling pathways contributed to the resistance of hybrid tilapia. Notably, immune response genes in hybrid tilapia, such as P38, TLR5, CXCR3, CXCL12, PSTPIP1, and TFR, were generally suppressed under normal conditions but selectively induced following pathogen challenge. These results expand our knowledge of the molecular mechanisms underlying S. agalactiae tolerance in hybrid tilapia and provide valuable insights for tilapia breeding programs.
Subject(s)
Cichlids , Fish Diseases , Streptococcal Infections , Tilapia , Animals , Tilapia/genetics , Cichlids/genetics , Transcriptome , Streptococcus agalactiae/physiology , Gene Expression Profiling/veterinaryABSTRACT
This paper proposes an extended prism coupling analysis method to accurately analyze the coupling structure of liquid crystal (LC) cladding waveguide beam steerer. We analyze the effects of LC anisotropy on the coupling of transverse electric (TE) and transverse magnetic (TM) modes and derive the expression of the optical field distribution that perfectly matches the given coupling structure. Based on this method, we present the optimal coupling structure for Gaussian beam. Taking into account the practical manufacturing process, we propose a simplified coupling structure and perform a detailed analysis of its performance based on numerical simulations. Experimental results show a coupling efficiency of 91% and a coupling angle full width at half maximum (FWHM) of about ±0.02°, demonstrating the effectiveness of the proposed method in predicting the coupling performance of anisotropic cladding waveguides.
ABSTRACT
Understanding the behavior of gas bubbles in aqueous media has been a hot topic because of their vital roles in both scientific research and industrial applications. Wettability gradient force and Laplace pressure are two typical characteristics of bubble transport. However, most work about bubble transport is limited to a short distance. Therefore, we took inspiration from the structure of the Nepenthes pitcher and prepared superaerophobic dual-rail arrays (SDRA). Upon SDRA, with this structure of a uniform distribution of superaerophobic and superaerophilic zones, bubbles can be transported over long distances on the structure's surface. The underlying principle is that gas bubbles tend to spread out on the superaerophilic region until they make contact with the asymmetric superaerophobic barriers. An asymmetric spreading resistance force is generated, which is attributed to the different lengths of the three-phase contact line (TCL) between gas bubbles and superaerophobic barriers. In addition, diverse parameters are quantified to investigate the critical transport state between unidirection and bidirection. Under the function of SDRA, the structure surface can realize bubble collection. The transporter as well as the light-control-light shutter is also successfully deployed. The present study will inspire people to develop innovative strategies to effectively manipulate gas bubbles in practical applications.
Subject(s)
Lasers , Humans , WettabilityABSTRACT
Collaborative testing has been demonstrated the ability to improve students' performance, enhance students' learning, and aid in knowledge retention in many different courses. However, this examination mode lacks the process of teacher feedback. Herein, a short teacher feedback from was added immediately after the collaborative testing to improve the students' performance. A parasitology class of 121 undergraduates was randomized into two groups: group A and group B. Collaborative testing was carried out at the end of theoretical teaching. During the test, students would first answer questions as individuals for 20 minutes. Then, students from group A answered the same questions in groups (5 students in each group) for 20 minutes, while the group-testing duration was only 15 minutes in group B. Immediately after the group testing, teachers conducted a 5-minute feedback about the morphology identification according to the analysis of the answers by group B. Four weeks later, a final test was conducted in an individual test. The total scores and scores for each examination content were analyzed. The results showed that there was no significant difference in the final exam scores between both groups (t = -1.278, P = 0.204). However, the morphological and diagnostic test results of the final examination in group B were significantly higher than those of the midterm examination, while there was no significant change in group A (t = 4.333, P = 0.051). The results confirmed that the teacher feedback after the collaborative testing can effectively make up for the students' knowledge gaps.NEW & NOTEWORTHY This study found that collaborative group testing is helpful for teachers to grasp students' knowledge gaps more easily and the teacher feedback after the collaborative group testing can effectively make up for the knowledge gaps of students.
Subject(s)
Students , Humans , FeedbackABSTRACT
The relatively high work pressure within an ion trap has limited the implementation of the Fourier transform technique for high resolution mass analysis. The main reason is that high buffer gas pressure will cause the rapid decay of ion oscillations. In this study, an image current splicing method based on the filter diagonalization method (FDM) and the Hilbert transform was developed to increase the resolving power of nondestructive mass analysis in a linear ion trap. First, multiple repeated experiments (or ion trajectory simulations) were performed to collect multiple sets of data. Using the FDM, the frequency component distribution was extracted from short image current transients collected from each experiment. The Hilbert transform was then applied to calculate and normalize the decay envelope of each transient. The relative abundance was calculated by counting the envelopes. Finally, image current transients collected from these multiple experiments were spliced and merged into a whole signal with much longer duration and continuous phase. This splicing method could effectively increase the duration of the image current, and thus improve the mass resolution of the ion trap mass analyzer. The mass resolution (m/Δm) was improved from 183.5 to 5.8 × 103, and the average relative difference was 2.8%. The proposed method resolved 3 adjacent peaks which originally could not be resolved from the raw signal by the fast Fourier transform (FFT). Besides simulated data, this method was also applied to the experimental data collected from a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer. The influence of electronic noise on the proposed method was also discussed in this study.
ABSTRACT
Biomimetic structures based on the magnetic response have attracted ever-increasing attention in droplet manipulation. Till now, most methods for droplet manipulation by a magnetic response are only applicable to a single droplet. It is still a challenge to achieve on-demand and precise control of multiple droplets (≥2). In this paper, a strategy for on-demand manipulation of multiple droplets based on magnetism-responsive slanted micropillar arrays (MSMAs) is proposed. The Glaco-modified superhydrophobic surface is the basis of multiple-droplet manipulation. The droplet's motion mode (pinned, unidirectional, and bidirectional) can be readily fine-tuned by changing the volume of droplets and the speed of the magnetic field. The rapid movement of droplets (10-80 mm/s) in the horizontal direction is realized by the unidirectional waves of the micropillar array driven by a specific magnetic field. The bending angle of micropillars can be rapidly and reversibly adjusted from 0 to 90° under the action of a magnetic field. Meanwhile, the liquid-involved light, electric switch, and biomedical detection can be designed by manipulating the droplets on demand. The superiority of MSMAs in multiple-droplet programmable manipulation opens up an avenue for applications in microfluidic and biomedical engineering.
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The physicochemical properties of functional graphene are regulated by compositing with other nano-carbon materials or modifying functional groups on the surface through plasma processes. The functional graphene films with g-C3N4 and F-doped groups were produced by controlling the deposition steps and plasma gases via radio frequency plasma-enhanced chemical vapor deposition (RF-PECVD). The first principles calculation and electrochemistry characteristic of the functional graphene films were performed on Materials Studio software and an electrochemical workstation, respectively. It is found that the nanostructures of functional graphene films with g-C3N4 and F-doped groups were significantly transformed. The introduction of fluorine atoms led to severe deformation of the g-C3N4 nanostructure, which created gaps in the electrostatic potential of the graphene surface and provided channels for electron transport. The surface of the roving fabric substrate covered by pure graphene is hydrophilic with a static contact angle of 79.4°, but the surface is transformed to a hydrophobic state for the g-C3N4/graphene film with an increased static contact angle of 131.3° which is further improved to 156.2° for CF2-modified g-C3N4/graphene film exhibiting the stable superhydrophobic property. The resistance of the electron movement of CF2-modified g-C3N4/graphene film was reduced by 2% and 76.7%, respectively, compared with graphene and g-C3N4/graphene.
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In this study, multiple heterojunction structures of anatase-rutile/Bismuth oxyiodide (BiOI) composite fibers are designed by the combined method of electrospinning and hydrothermal techniques. The influence of different Ti/Bi atomic ratios ([Ti/Bi]) on the nanostructures and photocatalytic properties are investigated. It is found that the morphology of BiOI covered on the TiO2 fiber surface changed with [Ti/Bi] from nanosheets to submicron spheres structures. Additionally, the crystallization of the composite fibers including the phases of anatase, rutile, and BiOI is identified, theses phases are in close contact with each other, and the interfacial effects are helpful to form the multiple heterojunctions which lead to blue shifts on the chemical state of Ti. The absorption of visible light has been improved by compositing BiOI on TiO2, while the band gap values of the composite fibers are significantly reduced, which can enhance the generation and separation of electrons and holes. For the case of [Ti/Bi] = 1.57, the photodegradation rate of anatase-rutile/BiOI composite fibers is about 12 times that of pure TiO2. For the photocatalytic mechanism, the synergistic s-type heterojunctions increase the content of active oxides which have a positive effect on the degradation rate.
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Superwetting surface can be divided into (super) hydrophilic surface and (super) hydrophobic surface. There are many methods to control superwetting surface, among which plasma technology is a safe and convenient one. This paper first summarizes the plasma technologies that control the surface superwettability, then analyzes the influencing factors from the micro point of view. After that, it focuses on the plasma modification methods that change the superwetting structure on the surface of different materials, and finally, it states the specific applications of the superwetting materials. In a word, the use of plasma technology to obtain a superwetting surface has a wide application prospect.
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Since December 2019, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread throughout the world and has had a devastating impact on health and economy. The biochemical characterization of SARS-CoV-2 proteins is important for drug design and development. In this study, we discovered that the SARS-CoV-2 nucleocapsid protein can melt double-stranded DNA (dsDNA) in the 5'-3' direction, similar to SARS-CoV-2 nonstructural protein 13. However, the unwinding activity of SARS-CoV-2 nucleocapsid protein was found to be more than 22 times weaker than that of SARS-CoV-2 nonstructural protein 13, and the melting process was independent of nucleoside triphosphates and Mg2+. Interestingly, at low concentrations, the SARS-CoV-2 nucleocapsid protein exhibited a stronger annealing activity than SARS-CoV-2 nonstructural protein 13; however, at high concentrations, it promoted the melting of dsDNA. These findings have deepened our understanding of the SARS-CoV-2 nucleocapsid protein and will help provide novel insights into antiviral drug development.
ABSTRACT
Metabolic capacity is intrinsic to growth performance. To investigate superior growth performance in Nile tilapia, three full-sib families were bred and compared at the biochemical and transcriptome levels to determine metabolic mechanisms involved in significant growth differences between individuals under the same culture environment and feeding regime. Biochemical analysis showed that individuals in the higher growth group had significantly higher total protein, total triglyceride, total cholesterol, and high- and low-density lipoproteins, but significantly lower glucose, as compared with individuals in the lower growth group. Comparative transcriptome analysis showed 536 differentially expressed genes (DEGs) were upregulated, and 622 DEGs were downregulated. These genes were significantly enriched in three key pathways: the tricarboxylic acid cycle (TCA cycle), fatty acid biosynthesis and metabolism, and cholesterol biosynthesis and metabolism. Conjoint analysis of these key pathways and the biochemical parameters suggests that Nile tilapia with superior growth performance have higher ability to consume energy substrates (e.g., glucose), as well as higher ability to biosynthesize fatty acids and cholesterol. Additionally, the fatty acids biosynthesized by the superior growth performance individuals were less active in the catabolic pathway overall, but were more active in the anabolic pathway, and might be used for triglyceride biosynthesis to store excess energy in the form of fat. Furthermore, the tilapia with superior growth performance had lower ability to convert cholesterol into bile acids, but higher ability to convert it into sterols. We discuss the molecular mechanisms of the three key metabolic pathways, map the pathways, and note key factors that may impact the growth of Nile tilapia. The results provide an important guide for the artificial selection and quality enhancement of superior growth performance in tilapia.
ABSTRACT
Fourier ptychography is a promising and flexible imaging technique that can achieve 2D quantitative reconstruction with higher resolution beyond the limitation of the system. Meanwhile, by using different imaging models, the same platform can be applied to achieve 3D refractive index reconstruction. To improve the illumination NA as much as possible while reducing the intensity attenuation problem caused by the LED board used in the traditional FP platform, we apply a hemispherical lighting structure and design a new LED arrangement according to 3D Fourier diffraction theory. Therefore, we could obtain the illumination of 0.98NA using 187 LEDs and achieve imaging half-pitch resolutions of â¼174â nm and â¼524â nm for the lateral and axial directions respectively, using a 40×/0.6NA objective lens. Furthermore, to reduce the number of captured images required and realize real-time data collection, we apply the multiplexed-coded illumination strategy and compare several coded patterns through simulation and experiment. Through comparison, we determined a radial-coded illumination pattern that could achieve more similar results as sequential scanning and increase the acquisition speed to above 1â Hz. Therefore, this paper provides the possibility of this technique in real-time 3D observation of in vitro live samples.