理学最新文献

Microvibrations caused by airflow self-excitation within pressurized air films significantly degrade the dynamic stability of aerostatic bearings. However, effectively controlling supersonic flow velocity, which is critical for suppressing the turbulent airflows that cause this self-excitation, remains a significant challenge in the current designs of aerostatic bearings. To address this gap, a novel aerostatic restrictor inspired by the Laval nozzle principle is proposed to enhance the dynamic stability of bearings by decelerating supersonic pressurized airflows. Computational fluid dynamics (CFD) simulations are conducted to elucidate the underlying mechanism by which the proposed restrictor improves performance (i.e., by suppressing turbulent airflows by mitigating adverse pressure gradients). On the basis of the CFD simulation results, the key geometrical parameters of the newly designed restrictor are identified. The effectiveness of the proposed restrictor is evaluated through experimental testing, with the results indicating that it achieves improved dynamic stability and reduced vibration amplitude compared with a conventional aerostatic restrictor design. This work is expected to advance the theory of restrictor design by enhancing the dynamic stability of aerostatic bearings.

Background: An imbalance in the rumen microbiota caused by high-concentrate diets (HCD) is a significant endogenous trigger of mastitis. However, the underlying mechanisms remain largely unknown. Microbial extracellular vesicles (mEVs) are critical mediators of microbe-host communication. However, the role of mEVs in rumen microbiota-mediated mastitis has not yet been reported. In this study, we used an HCD-induced rumen microbiota dysbiosis model to investigate the role of mEVs-derived from rumen microbiota in the pathogenesis of mastitis.

Results: Our results indicate that HCD leads to mastitis and systemic inflammation. Meanwhile, HCD-fed goats exhibited substantial rumen microbiota dysbiosis and the disruption of the rumen barrier. Transplanting rumen microbiota from HCD goats into mice induced both mastitis and systemic inflammation in the recipients. Specifically, HCD increases the production of mEVs carrying microbial DNA, which can translocate across the compromised rumen barrier to the mammary gland, triggering a mammary inflammatory response via activation of the cGAS-STING-NF-κB/NLRP3 pathway. Furthermore, treating mice with mEVs isolated from the rumen fluid of HCD goats directly induced mastitis, whereas depletion of microbial DNA attenuated mEVs-induced mastitis.

Conclusion: Our findings suggest that HCD induces rumen microbiota dysbiosis and impairs rumen barrier function. This dysfunction leads to an increase in microbial DNA-containing mEVs, which subsequently leak into the mammary gland. Once there, these mEVs activate the cGAS-STING-NF-κB/NLRP3 signaling pathway, ultimately inducing mastitis. This study provides a new perspective on the "rumen microbiota-mammary gland axis" and enhances the understanding of the pathogenesis of mastitis.

Viral infections of the ocular surface significantly contribute to morbidity and visual impairment globally. The herpes simplex virus (HSV), adenovirus, cytomegalovirus (CMV), and human papillomavirus (HPV) are predominant pathogens impacting the cornea and conjunctiva, resulting in recurrent illness, epidemic outbreaks, and virus-associated neoplasia. Progress in virology, immunology, and molecular diagnostics has enhanced comprehension of host-virus interactions and introduced novel therapeutic opportunities. A narrative literature review was performed utilizing PubMed, Scopus, and Web of Science, encompassing papers published from 2000 to 2025, with a specific focus on research from 2020 onwards. Eligible publications were peer-reviewed clinical and experimental investigations, together with reviews that focused on epidemiology, etiology, diagnostic methodologies, and therapeutic alternatives. Research indicates that HSV keratitis is the predominant infectious cause of corneal blindness in high-income nations, although adenovirus persists in instigating epidemics of keratoconjunctivitis in the absence of licensed antiviral treatments. CMV keratitis, previously confined to immunocompromised persons, is now acknowledged in immunocompetent patients as a causative agent of corneal endotheliitis. HPV is associated with ocular surface squamous neoplasia, especially in areas with elevated ultraviolet exposure and high human immunodeficiency virus prevalence. Innovative molecular diagnostics, innovative antiviral agents, immunomodulatory approaches, and immunization initiatives signify significant progress that could enhance preventative and therapeutic results.