Search Results (26)

High-speed and broadband waveform generation based on using a Sinc² sampled fiber grating (SFG) combined with a femtosecond laser source is investigated. The Sinc² SFG provides linear wavelength divided multiplexing (WDM) time delay lines (TDLs) with sub-picosecond delay steps, and two types of reflectivity spectrum with flat-top and linear profiles for a large number of wavelength channels. The femtosecond laser is used as a broadband source. Simulation results demonstrate that the generation of rectangular and sawtooth waveforms is achieved through numerical modeling based on wavelength-to-time mapping using a grating TDL and an ultrafast laser. Results show, for example, that a rect waveform is generated with a repetition frequency (f_rep) of 125 GHz, a period (T) of 8 ps, and a rise-fall time of 4% T; a sawtooth waveform is generated with a f_rep of 69.5 GHz, a period of 14.39 ps, a rise time of 2.8% T, and a ramp linearity of 0.1% standard deviation. Full article

The emergence and global dissemination of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli (ESBL-E. coli) represent a major public health concern. However, the characterization and capacity for horizontal gene transfer (HGT) of ESBL-E. coli in captive black bears remain substantially understudied. In the present study, 19 ESBL-E. coli strains were successfully identified (13.38%, 19/142). A total of 11 sequence types (STs) were identified from 19 ESBL-E. coli strains using MLST. This included eight known types (ST10, ST2690, ST208, ST695, ST4160, ST540, ST3865 and ST2792) and three new STs. Antimicrobial susceptibility testing demonstrated that all 19 ESBL-E. coli exhibited high resistance to KZ (100.00%), CRO (78.95%), and CTX (73.68%). Polymerase chain reaction (PCR) screening for 14 β-lactam antibiotic resistance genes (ARGs) and their variants revealed that bla_CTX-M was the most prevalent, followed by bla_SHV, bla_TEM, and bla_DHA. Furthermore, eight β-lactamase variants were detected, including five bla_CTX-M variants (bla_CTX-M-15, bla_CTX-M-3, bla_CTX-M-14, bla_CTX-M-55, and bla_CTX-M-27) and one variant each of bla_SHV-1, bla_TEM-1, and bla_DHA-14. Conjugation assays revealed that eight ESBL-E. coli strains were capable of conjugative transfer. Five plasmid types (IncFII, IncW, IncFrepB, IncY, and IncHI1) and three mobile genetic elements (MGEs) (IS26, ISEcp1, and trbC) were identified as co-transferred with bla_CTX-M. ESBL-E. coli poses a potential threat to captive black bears and may lead to further transmission. Consequently, the implementation of continuous surveillance and targeted interventions is imperative to prevent the transmission of ESBL-E. coli. Full article

Background: Fasciola hepatica causes important economic losses in ruminants with only pharmacological treatments currently available, which produces several secondary problems. Because of this, vaccines have become an interesting alternative. Leucine aminopeptidases (LAPs) are attractive vaccine targets against fasciolosis since they play essential roles in the parasite such as host invasion and nutrient acquisition. To characterize immune responses, we produced two recombinant F. hepatica LAPs (FhLAP1 and FhLAP2), formulated with ISCOM-matrices (IMXs) nanoparticles from Quillaja brasiliensis saponins. Methods: Forty female Corriedale sheep were assigned to four groups (n = 10): FhLAP1/IMX, FhLAP1/FhLAP2/IMX, IMX (control), and FhLAP1/Adj50 (Adjuvac 50). Animals received two subcutaneous immunizations at weeks 0 and 4 and were challenged orally with 200 metacercariae at week 6. Results: FhLAP1 and FhLAP1/FhLAP2 induced specific IgG responses, with the predominance of the IgG1 response. However, these responses were lower than those generated by FhLAP1 formulated with Adj50. A qPCR analysis revealed that FhLAP1/IMX stimulated a Th1-type response profile before the challenge, but this profile was not sustained after infection. The post-infection profile of FhLAP1/FhLAP2/IMX was more congruent with expected values despite not achieving a robust IFN-γ expression. No significant differences in the fluke burden were observed. Conclusions: Further research on the optimal antigen/adjuvant combination in ruminants is encouraged. For instance, a higher concentration of adjuvant in the formulation used in this work may enhance the strength and duration of the inflammatory response and improve protective immunity against fasciolosis. Full article

Currently, train component fault detection is predominantly carried out through manual inspection, a process that is inefficient, prone to high omission rates, and carries safety risks. This study proposes an innovative fault detection model for train components based on YOLOv8, aiming to overcome the inefficiencies and high omission rates associated with traditional manual methods. By optimizing the YOLOv8 network architecture and integrating the ADown module, C2f-Rep, and DHD, the model significantly improves computational efficiency and detection accuracy. Experimental results demonstrate that the optimized Train-YOLO model achieves a peak accuracy of 92.9% in train component fault detection. Additionally, it features a smaller model size and reduced computational demands, making it ideal for rapid on-site deployment. A comparison with other leading detection models further highlights the superiority of Train-YOLO in both accuracy and lightweight design. Full article

To meet the environmental protection and flame retardancy requirements for epoxy resins (EPs) in certain fields, in this study, a novel triazine-ring-containing DOPO-derived compound (VDPD), derived from vanillin, 2,4-Diamino-6-phenyl-1,3,5-triazine, and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), was synthesized using a one-pot method. Flame-retardant epoxy resin (FREP) was prepared by adding various ratios of VDPD to EP and curing with 4,4-diaminodiphenylmethane (DDM). The curing behavior, thermal stability, mechanical properties, and flame-retardant properties of the FREP were examined in various tests. According to the results, when the amount of VDPD added to the EP increased, the glass transition temperature of the FREP decreased linearly, and the flame-retardant properties gradually improved. With a 0.4 wt.% P content, the vertical burning rating of EP/DDM/VDPD-0.4 (according to the theoretical content of VDPD) reached the V-0 level, and the LOI value reached 33.1%. In addition, the results of a CCT showed that the peak heat release rate (PHRR) of EP/DDM/VDPD-0.4 decreased by 32% in comparison with that of the EP. Furthermore, compared with those of the EP, the tensile strength of EP/DDM/VDPD-0.4 decreased from 80.2 MPa to 74.3 MPa, only decreasing by 6 MPa, and the tensile modulus increased. Overall, VDPD can maintain the mechanical properties of EP and effectively improve its flame-retardant properties. Full article

To assess the effects of reforestation on ecosystem carbon storage, a long-term Forest Restoration Experimental Project (FREP) was established in 1991 on southern degraded red soil in Taihe County, Jiangxi Province, China. In this study, we selected five types of plantations: Schima superba plantation (SS), Liquidambar formosana plantation (LF), Pinus massoniana plantation (PM), Pinus elliottii plantation (PE), and P. elliottii and broadleaf mixed plantation (MEB). The unforested land was used as an experimental control check (CK). We aimed to assess the changes in carbon storage in plantations and the factors affecting them. Thirty years after reforestation, the ecosystem carbon storage of the five types of plantations was significantly higher than that of the control site, and there were also significant differences in the ecosystem carbon storage between the different plantation types (p < 0.05). The ecosystem carbon storage of SS, MEB, LF, PM, and PE were 211.71 Mg ha⁻¹, 199.02 Mg ha⁻¹, 160.96 Mg ha⁻¹, 155.01 Mg ha⁻¹, and 142.88 Mg ha⁻¹, respectively. Compared to the CK, these values were increased by 436.8%, 404.6%, 308.1%, 293.1%, and 262.3%, respectively. The ecosystem carbon storage was significantly positively correlated with soil porosity, total nitrogen (TN), and stand density, and was significantly negatively correlated with pH, Pielou’s evenness index (PEI), and the Shannon–Weiner diversity index (SWDI). The soil water content (SWC), bulk density (BD), SWDI, and stand density can be used as indicators of the impact of reforestation plantings on ecosystem carbon storage. The research results has shown that reforestation plantings significantly increase ecosystem carbon storage, and that afforestation should be encouraged on degraded land. Full article

Flammulina rossica fermentation extract (FREP) was obtained by ethanol precipitation of the fermentation broth. The molecular weight of FREP is 28.52 kDa, and it mainly contains active ingredients such as polysaccharides, proteins, reducing sugars, and 16 amino acids. Among them, the polysaccharides were mannose, glucose, galactose, arabinose, and fucose and possessed β-glycosidic bonds. Furthermore, the immunoregulatory activities of FREP were investigated in vivo. The results demonstrated that FREP could increase the counts of CD⁴⁺ T lymphocytes and the ratio of CD⁴⁺/CD⁸⁺ in a dose-dependent manner in healthy mice. In addition, FREP significantly increased serum cytokines, including IL-2, IL-8, IL-10, IL-12, IL-6, IL-1β, INF-γ, C-rection protein, and TNF-α, and promoted splenocyte proliferation in healthy mice. Finally, FREP could restore the counts of white blood cells, red blood cells, secretory immunoglobulin A, and antibody-forming cells and significantly promote the serum haemolysin level in mice treated with cyclophosphamide. The findings indicated that FREP possessed immunoregulatory activity in healthy mice and could improve the immune functions in immunosuppressive mice. Therefore, FREP could be exploited as an immunomodulatory agent and potential immunotherapeutic medicine for patients with inadequate immune function. Full article

Large-area nanostructuring of glasses using intense laser beams is a challenging task due to the material’s extreme non-linear absorption of laser energy. Precise optimization of the process parameters is essential for fabricating nanostructures with large-area coverage. In this study, we report the findings on creating high-spatial-frequency LIPSS (HSFL) on borosilicate glass through direct laser writing, using a femtosecond laser with a wavelength λ = 800 nm, pulse duration τ = 35 fs, and repetition frequency f_rep = 1 kHz. We measured the single-pulse ablation threshold and incubation factor of Borosilicate glasses to achieve high-precision control of the large-area surface structuring. Single-spot experiments indicated that, when there was higher fluence and a larger number of irradiated laser pulses, a melt formation inside the irradiated area limited the uniformity of LIPSS formation. Additionally, the orientation of the scan axis with the laser beam polarization was found to significantly influence the uniformity of LIPSS generated along the scan line, with more redeposition and melt formation when the scan axis was perpendicular to the laser beam polarization. For large-area processing, the borosilicate glass surface was scanned line-by-line by the laser beam, with a scan orientation parallel to the polarization of the laser. The optical characterization revealed that the transmittance and reflectance of the borosilicate glass decreased significantly after processing. Additionally, the surface’s wettability changed from hydrophilic to super-hydrophilic after processing. These chemical contamination-free and uniformly distributed structures have potential applications in optics, microfluidics, photovoltaics, and biomaterials. Full article

To endow synergistically epoxy resin (EP) with excellent fire resistance and high optical transparency, a nitrogen-rich DOPO-based derivate (named as FATP) was synthesized and incorporated into EP. It showed that the incorporation of the FATP reduced the fire hazard of the EP, as demonstrated by the fact that the EP/4% FATP blends gained a UL-94 V-0 rating and an LOI value of 35%, with the lowest values of the THR (86.7 MJ/m²), the PHRR (1059.3 kW/m²), and the TSP (89.6 MJ/m²). The presence of the FATP also reduced the thermal stability and the crosslinking density whilst improving the curing reaction and the storage modulus of the EP/FATP blends. The TG-FTIR spectra showed that •HPO/•PO free radicals and some nonflammable gases (HN₃ and NH₃) were produced during the pyrolysis, and the characterization (SEM, Raman spectroscopy, and XPS) of char residues confirmed that the FATP facilitated the formation of continuous and compact carbon layers of greater graphitization degree. It was thus concluded that the FATP played the flame-retardant roles in both the gas and condensed phases. Furthermore, the FREPs kept almost identical transparency as the pristine EP, and mechanical properties were also slightly enhanced. The FREPs presented in this work show promising applications in the fields of advanced optical technology. Full article

A novel bio-based flame retardant designated AVD has been synthesized in a one-pot process via the reaction of 9,10-dihydro-9-oxa-10-phospha-phenanthrene-10-oxide (DOPO), vanillin (VN), and 2- aminobenzothiazole (ABT). The structure of AVD was confirmed using Fourier transform infrared spectroscopy (FTIR), and ¹H and ³¹P nuclear magnetic resonance spectroscopy (NMR). The curing process, thermal stability, flame retardancy, and mechanical properties of the epoxy resin (EP) modified with AVD have been investigated comprehensively. The extent of curing, the glass transition temperature and the crosslinking density of the blend decreased gradually with increasing AVD content. The thermogravimetric analysis (TGA) was used to demonstrate that the presence of AVD reduced the thermal decomposition rate for EP and enhanced the formation of carbon residue during resin decomposition. A blend of 7.5 wt% AVD (0.52% phosphorus) displays a UL-94V-0 rating and a LOI of 31.1%. Reduction of the peak heat release rate, total heat release rate and total smoke production was 41.26%, 35.70%, and 24.03%, respectively, as compared to the values for pure EP. The improved flame retardancy of the flame retardant epoxy (FREP) may be attributed to the formation of a compact and continuous protective char layer into the condensed phase as well as the release of non-combustible gases and phosphorus-containing radicals from the decomposition of AVD in the gas phase. AVD is a new and efficient biobased flame retardant for epoxy with great prospects for industrial applications. Full article

Pattern recognition receptors (PRRs) play important roles in detecting pathogens and initiating the innate immune response. Different evolutionary histories of pollinators and non-pollinators may result in different immune recognition systems. A previous study had reported that there were significant differences in peptidoglycan recognition proteins (PGRPs) between pollinators and non-pollinators in gene number and lineage of specific genes. In this study, based on the genomic data of 12 fig wasp species, with seven pollinators and five non-pollinators, we investigated the evolution patterns of PRRs, such as Gram-negative bacteria-binding proteins (GNBPs), C-type lectins (CTLs), scavenger receptors class B (SCRBs), fibrinogen-related proteins (FREPs), galectins, and thioester-containing proteins (TEPs). Our results showed that pollinators had no GNBP, but non-pollinators all had two gene members, which were clustered into two different clades in the phylogenetic tree, with each clade having specific domain and motif characteristics. The analysis of CTL and SCRB gene families also showed that there were lineage-specific genes and specific expansion in non-pollinators. Our results showed that there were significant differences in immune recognition between pollinators and non-pollinators, and we concluded that they had undergone flexible adaptive evolution in different environments. Our study can provide more molecular evidence for future functional studies on the immune system of fig wasps. Full article

Although foamed plastic insulation is widely used in construction in the Korean market, it is vulnerable to fire. To improve the flame retardancy, the method of flame-retardant coating with the EG in water-soluble state on the surface of expanded polystyrene (EPS) beads has been widely used. However, polystyrene beads coated with a water-soluble flame retardant easily separate the coated flame retardant in manufacturing. In this study is devised a flame-retardant coating and two steps of coating process for adhering the flame-retardant coating film evenly to the surface of the polystyrene bead without exfoliation. It was analyzed whether a flame-retardant EPS (FR-EPS) with excellent flame retardancy could be manufactured using polystyrene beads coated in this way. Ten FR-EPS samples satisfied the HF-1 and V-0 levels in horizontal and vertical burning tests, respectively. The THR of eight FR-EPS samples for ten minutes did not exceed 8 MJ∙m⁻² and the maximum HRR did not exceed 200 kW∙m⁻² for more than ten consecutive seconds. FR-EPS passed the building material standard of semi-nonflammability in Korean regulations, in contrast to commercial EPS, which have not passed the semi-nonflammability standard. It was also analyzed how effective the designed coating is in this study, comparing it with composites that were planned to improve the flame resistance of polystyrene, as reported in the literature. Flame Retardancy Index (FRI) values of FR-EPS proved the “excellent” level and had higher values compared with other polystyrene composites. These results demonstrated that the coated EPS containing a water-soluble flame retardant manufactured from EG and two steps of application with the coating solution achieved fire safety standard regulations. Full article

Additive manufacturing (AM) has a greater potential to construct lighter parts, having complex geometries with no additional cost, by embedding cellular lattice structures within an object. The geometry of lattice structure can be engineered to achieve improved strength and extra level of performance with the advantage of consuming less material and energy. This paper provides a systematic experimental evaluation of a series of cellular lattice structures, embedded within a cylindrical specimen and constructed according to terms and requirements of ASTMD1621-16, which is standard for the compressive properties of rigid cellular plastics. The modeling of test specimens is based on function representation (FRep) and constructed by fused deposition modeling (FDM) technology. Two different test series, each having eleven test specimens of different parameters, are printed along with their replicates of 70% and 100% infill density. Test specimens are subjected to uniaxial compressive load to produce 13% deformation to the height of the specimen. Comparison of results reveals that specimens, having cellular lattice structure and printed with 70% infill density, exhibit greater strength and improvement in strength to mass ratio, as compared to the solid printed specimen without structure. Full article

Hypersensitivity to galactose-α-1,3-galactose (α-gal) is an informative example of a pathologic IgE-mediated process. By way of their saliva, ticks are able to sensitize humans to tick dietary elements that express α-gal. Mites, which along with ticks constitute the phyletic subclass Acari, feed on proteinaceous foodstuffs that represent most, if not all, human allergens. Given: (1) the gross nature of the pathophysiological reactions of allergy, especially anaphylaxis, (2) the allergenicity of acarian foodstuffs, and (3) the relatedness of ticks and mites, it has been hypothesized that human-acarian interactions are cardinal to the pathogenesis of allergy. In this report, a means by which such interactions contribute to that pathogenesis is proposed. Full article

Additive manufacturing erases the distance between design ideas and finished parts. However, designers must use several software tools to use these advantages. Moreover, these tools operate with different representations of geometry. This paper describes the architecture of a new CAD/CAM system that uses only the function representation of the geometry (FRep). It provides all widely used design operations and allows an engineer to employ robust and efficient topology optimization algorithms. The developed CAD/CAM system consists of 3D modeling, simulation, topology optimization, and direct manufacturing modules. We successfully printed designed parts and performed mechanical tests of printed parts. The results of tests show good agreement with simulation data. The system makes it possible to create structures with the desired properties in a fast and flexible way. The proposed approach significantly helps in designing additive manufacturing process and saves time for its users. Full article