Porcine reproductive and respiratory syndrome virus type 1 (PRRSV-1) primarily circulates in Europe but is also detected in North America and Asia. Based on ORF5 sequences, previous studies classified PRRSV-1 into four subtypes. Subtype 1 was further classified into 12 clades (A-L) or into three lineages with lineage 1 including clades 1A1G and lineage 3 including clades 3A3G, but the systems are inconsistent and have not been adopted. In this study, we proposed a statistically supported PRRSV-1 genetic classification system based on 10,446 global PRRSV-1 ORF5 sequences spanning 19912023. We replaced the colloquial “subtype” designation with “lineage” to reflect evolutionary history and, subsequently, PRRSV-1 was classified into four lineages (L1L4) with L1 including 18 sublineages (L1.1 to L1.18). The proposed classification system is flexible and may be amended if additional lineages, sublineages, or more granular classifications are needed to reflect contemporary PRRSV-1 detections and evolution. Geographic distributions of PRRSV-1 at lineage and sublineage levels were distinct, with L1 globally distributed and L2, L3 and L4 more restricted. Temporal dynamic changes in some countries were quantified. Classification and ORF5 nucleotide identity of six commercial PRRSV-1 vaccines to each lineage and sublineage and detection frequency of vaccine-like viruses were determined. The phylogenies based on whole-genome and ORF5 sequences demonstrated slightly different tree topologies. Recombination of PRRSV-1 was observed at within-sublineage and between-sublineage levels. A set of ORF5 reference sequences representing the refined classification is available for future diagnostic and epidemiological applications. This study provides a benchmark delineating the current genetic diversity of PRRSV-1 and introduces a refined classification system to support the global standardization and application of ORF5-based genetic classification for PRRSV-1.
Avian influenza viruses continue to challenge poultry and human health; therefore, careful surveillance and evaluation of emerging viruses are important for animal disease control and human influenza pandemic preparedness. In this study, we detected a series of H3N3 subtype avian influenza viruses in chickens, pigeons, and ducks during our routine surveillance and diagnosis between September 2022 and May 2023. We performed extensive analyses to fully understand the origins of these viruses and their risk to animals and humans. We found that the viruses were complex reassortants; the viruses from chickens and pigeons carry genes mainly derived from H3N8 viruses and H10N3 viruses, whereas the two duck viruses were reassortants of duck and wild bird viruses. The chicken and pigeon, but not duck, viruses replicated in multiple organs of chickens and were shed for up to 13 days, but none caused disease or death. Six of the viruses tested all bound to both avian- and human-type receptors. Seventeen viruses were tested in mice and most replicated efficiently but were not lethal. Six viruses were tested in guinea pigs, and four of them transmitted efficiently via respiratory droplets. Our study thus identified novel H3N3 avian influenza viruses and revealed their zoonotic potential, thereby emphasizing the importance of careful monitoring and control of H3 viruses in animals.
Background and Aim:Salmonella Abortusequi is a significant etiological agent of equine abortions, yet limited genomic data exist, particularly in Central Asia. This study aimed to perform the first genome-wide characterization and phylogenetic analysis of three S. Abortusequi strains isolated from equine abortions in different regions of Kazakhstan. Materials and Methods:Whole-genome sequencing was conducted on three isolates using the Illumina MiSeq platform. Genomic assemblies were annotated using SPAdes and Prokka, while phenotypic traits were predicted through BioNumerics. Antimicrobial resistance genes, virulence factors, and prophage elements were identified using established databases. Phylogenetic relationships were examined through whole-genome single-nucleotide polymorphism (wgSNP) analysis against a global panel of S. Abortusequi and related serovars. Results:All isolates displayed high genomic similarity and were classified as Salmonella enterica subsp. enterica serovar Abortusequi with an antigenic profile of 4:a:e,n,x. Twelve Salmonella pathogenicity islands and three prophages were identified, with ST64B present in all isolates. The ac(6')-Iaa gene, which confers resistance to aminoglycosides, was detected in all strains. Each genome encoded 101-109 virulence factors, with 94 conserved across isolates. wgSNP analysis confirmed close phylogenetic clustering of the Kazakh strains, with regional variation between northern and southern isolates. Prophage-associated virulence elements, particularly virulence factor protein (SseK), were also documented. Conclusion:This study reveals the genetic uniformity and virulence potential of S. Abortusequi strains circulating in Kazakhstan. The presence of conserved resistance and virulence genes, including prophage-encoded elements, underscores the pathogenic risk posed by these isolates. These findings contribute valuable genomic data for surveillance, diagnosis, and control of salmonellosis in equine populations. Despite the limited sample size, the study establishes a foundation for future genomic epidemiological studies and targeted disease mitigation strategies.
Slender beam structures, as core load-bearing components in fields such as aerospace, civil engineering, architecture, and mechanical equipment, have vibration characteristics that directly impact the system’s dynamic performance, operational safety, and service life. To control vibrations in slender beam structures, scholars have designed nonlinear vibration absorption devices. The aforementioned studies primarily discuss the vibration control potential of single or double NESs on slender beam structures subjected to harmonic excitation. However, in practical engineering applications, slender beams are often exposed to multiple vibrational excitations. Moreover, these structures typically provide sufficient installation space, allowing for the implementation of multiple NESs. Motivated by these engineering backgrounds and the limitations of existing research, this work proposes a slender beam with twin-source excitation and spatially distributed NESs simultaneously. The governing formula of the slender beam with twin-source excitation and spatially distributed NESs simultaneously is derived and solved. Based on the correct numerical results, the influence of core parameters of NESs, the phase difference of external excitation, and the spatial distribution of NESs on the vibration response of slender beam structures is discussed. The spatially distributed NESs can effectively suppress the peak vibration response of the slender beam structure. Second, the differences can be observed in the vibration displacement response of the slender beam structure with spatially distributed NESs under different phase differences. Regardless of the phase difference, the spatially distributed NESs consistently demonstrate effective vibration suppression in the slender beam structure. The appropriate selection of positions for spatially distributed NESs can enhance their vibration control effect on the slender beam structure. Overall, rational use of spatially distributed NESs can suppress vibrations in slender beam structures subjected to multiple excitations.
Objective As a core component of the opto-mechanical structure in large-scale optoelectronic equipment, the optical workbench directly affects the imaging quality of optical systems. The workbench must possess sufficient structural rigidity and a high lightweight ratio to minimize gravitational deformation, enhance portability, and improve maneuverability. In addition, it must exhibit high dimensional stability and minimal thermal deformation to ensure adaptability in ground environments. Utilizing new structures and materials has significant potential to refine large-size opto-mechanical designs and enhances the performance of ground-based optoelectronic equipment. In this paper, we propose the design of an optical workbench with honeycomb sandwich structure for a 430 mm clear aperture telescope, aiming to improve its lightweight ratio and thermal stability. Methods An equivalent modeling approach is developed to ensure high simulation accuracy for opto-mechanical components. In this method, carbon fiber reinforced plastic (CFRP) facepanels and aluminum honeycomb cores are modeled as shell elements with in-plane anisotropy and solid elements with orthogonal anisotropy, respectively. Equivalent physical properties of the facepanels are derived from the laminate theory, while those of the honeycomb cores are derived using the cellular geometry and material mechanics principles (Tables 1 and 2). Facepanels, prepared with M40J/cyanate ester prepreg at a thickness of 0.10 mm, feature a quasi-isotropic symmetric layup of [0 degrees/+/- 45 degrees/90 degrees]S to reduce moisture absorption and enhance long-term dimensional stability. Three types of aluminum alloy inserts, heavy-load, edge, and light-load, are designed to meet the various installation interfaces while maintaining the structure's stiffness and reliability (Fig. 4). Based on simulations, the facepanel thickness is determined to be 1.6 mm and the workbench height to be 40 mm, resulting in a final design weight of 3.03 kg for the 490 mm workbench (Fig. 3). The two parameters, facepanel thickness, and workbench height, together determine the stiffness of the workbench, which in turn affects the static and dynamic characteristics of the telescope (Fig. 5). To manufacture the complex honeycomb sandwich structure reliably, a combined hot bonding and cold bonding process is developed (Fig. 6). The main body is formed using hot bonding under high temperature and high pressure in an autoclave, while the inserts are bonded to the facepanels using an adhesive that cures at room temperature, completing the process. Results and Discussions Simulations show that under horizontal optical axis gravity, the relative displacement and angle between the primary and secondary mirrors are 8.09 mu m and 2.21 '', respectively, meeting the design requirements (Table 3). The quasi-isotropic CFRP facepanels exhibit low coefficients of thermal expansion, effectively minimizing in-plane thermal deformation. Under a 10 degrees C uniform temperature change, the RMS value of primary mirror surface accuracy deviation is 12.655 nm, well within the design requirements (RMS <=lambda /30, lambda =632.8 nm). Maximum stresses in the facepanels (8 MPa) and honeycomb core (0.4 MPa) are significantly below material strength limits. A forced displacement of 0.05 mm results in a negligible RMS surface accuracy deviation of 0.745 nm, confirming the workbench's capacity to uniformly transfer external loads. The proposed workbench with honeycomb sandwich structure exhibits good stiffness, thermal stability, and insensitivity to manufacturing errors and assembly stresses. Dimensional stability is verified through coordinate measuring machine (CMM) measurements of the facepanel inserts over six months, showing stable flatness with fluctuations below 5 mu m (ranging from 0.020 mm to 0.035 mm) (Fig. 7). To evaluate the system stability of the telescope, a mechanical prototype is constructed, and a high-precision photoelectric theodolite is used to monitor the relative elevation angles between the reference prisms on each component (Fig. 8). The test spans 1.5 months, during which the relative angles between the prisms remain stable, with a maximum drift of only 2.88 ''. Following alignment and assembly (Fig. 9), the system wavefront error of the actual telescope at the center field of view is measured to be RMS 36.45 nm at normal temperature (20 degrees C ), RMS 36.58 nm at relative low temperature (18 degrees C ), and RMS 36.64 nm at relative high temperature (23 degrees C ) (Fig. 10). These results demonstrate that the telescope consistently maintains excellent imaging quality within the ambient temperature range of 18-23 degrees C. Conclusions The monitoring data from the CMM confirms that the developed workbench has excellent long-term dimensional stability in conventional ground environments. The proposed honeycomb sandwich structure design is both feasible and reliable in terms of its preparation processes. Mechanical prototype testing further demonstrate that the optical system of the telescope, with the workbench as its core component, remains in a stable state, with no significant degradation in mechanical performance observed under ground conditions. In addition, the CFRP facepanels prepared with M40J/cyanate ester prepreg exhibit low moisture absorption, contributing to the workbench's stability. System wavefront error data shows that the telescope equipped with this workbench achieves good thermal stability and maintains accurate relative positioning between the primary and secondary mirrors, even as ambient temperature fluctuates within a certain range. The honeycomb sandwich workbench we proposed demonstrates high specific stiffness and stability, meeting the demands of high-performance opto-mechanical structures. This technical approach can also be applied to enhance the performance of similar equipment operating in conventional ground environments.
