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Objective Bench test is a primary technical means for studying the performance of high-speed EMU (electric multiple units) axle box bearings. Accurately simulating the practical operational load conditions of axle box bearings is essential for obtaining authentic and reliable performance data. A test bench for axle box bearings is reasonably designed to simulate the high-speed, heavy-load operational conditions. Control strategies for radial and axial loading mechanisms are developed to meet the requirements for control precision and response speed of the loading system. Method A dynamic loading system with electro-hydraulic servo is designed for the high-speed EMU axle box bearing reliability test bench. The structural composition and working principles of the axial and radial loading systems within this setup are introduced and a fuzzy-PID (proportional-integral-derivative) control algorithm is proposed. The axle box bearing reliability analysis test bench is constructed to conduct loading performance tests and axle box bearing reliability testing, thereby validating the rationality of the dynamic loading system. Result & Conclusion Test results indicate that the designed electro-hydraulic servo dynamic loading system meets the loading requirements for axle box bearing reliability test. The axial loading response time is 0.276 s, the axial loading steady-state error is 0.339 kN, and the radial loading steady-state error is 1.742 kN, all of which satisfy requirements specified in the EN 12082:2017 standards.

AIM: To observe the outcome of intravitreal balanced salt solution(BSS)injection to increase intraocular pressure(IOP)after extrascleral subretinal fluid drainage, then scleral buckling(SB)to treat superior bullous retinal detachment(SBRD), and compare it with the effect of conventional surgery(without any intravitreal filling)and postoperative air filling.METHODS: Retrospective case-control study. A total of 72 patients(73 eyes)who underwent SB for SBRD from January 2018 to December 2022 in ophthalmology department of Xijing Hospital were included. The extrascleral subretinal fluid drainage was performed in all eyes. According to whether intravitreal injection was performed and different injections, patients were divided into three groups: with 24 cases(24 eyes)in the conventional group(no intravitreal injection), 23 cases(23 eyes)in the air group(sterile air was injected after surgery), and 25 cases(26 eyes)in the BSS group(BSS was injected during extrascleral subretinal fluid drainage). All patients were followed up until subretinal fluid was absorbed completely. The average surgery time, postoperative IOP, retinal reattachment rate, subretinal fluid absorption, visual acuity(LogMAR)and major complications were compared.RESULTS: All surgeries were completed successfully. The average surgery time of the conventional group, air group and BSS group were 63.17±13.22, 61.65±15.55 and 57.30±11.70 min, respectively. There had no significant difference among these groups(F=0.825, P=0.443). On the first post-operative day, the average IOP of the conventional group, air group and BSS group were 13.69±2.69, 16.40±2.86 and 18.35±2.88 mmHg, respectively. The average IOP of the air group and the BSS group were significant higher than that of the conventional group(F=17.18, P0.05). The main complications included subretinal hemorrhage in 1 eye from the conventional group and 1 eye from the air group, and a new retinal tear in 1 eye from the air group, resulting in localized retinal detachment.CONCLUSIONS: For SBRD patients with hypotony during SB surgery, intravitreal injection of BSS to properly increase the IOP and then complete the surgery can improve the reattachment rate and reduce postoperative complications. This method is safe and effective for selected SBRD patients.

Given a graph G = (V (G) , E (G)) and a proper total k -coloring μ : V (G) ∪ E (G) → { 1 , 2 , ... , k } , we call μ neighbor sum distinguishing total coloring provided h (v) ≠ h (u) for any u v ∈ E (G) where h (v) = μ (v) + ∑ u v ∈ E (G) μ (u v) for any v ∈ V (G). Neighbor sum distinguishing total coloring was first defined by Pilśniak and Woźniak. They conjectured Δ (G) + 3 colors enable any graph G to admit such a coloring. The neighbor sum distinguishing total chromatic number χ Σ ′ ′ is the minimum integer where a graph is needed for this coloring. In this paper, we present two conclusions that χ Σ ′ ′ ≤ Δ (G) + 2 provided there are no 3-cycles adjacent to 4-cycles in a planar graph G with Δ (G) ≥ 8 without cut edges, and χ Σ ′ ′ ≤ Δ (G) + 3 provided there are no 4-cycles intersecting with 6-cycles in a planar graph G with Δ (G) ≥ 7. [ABSTRACT FROM AUTHOR]

The rs1061170T/C variant encoding the Y402H change in complement factor H (CFH) has been identified by genome-wide association studies as being significantly associated with age-related macular degeneration (AMD). However, the precise mechanism by which this CFH variant impacts the risk of AMD remains largely unknown. Oxidative stress plays an important role in many aging diseases, including cardiovascular disease and AMD. A large amount of oxidized phospholipids (oxPLs) are generated in the eye because of sunlight exposure and high oxygen content. OxPLs bind to the retinal pigment epithelium and macrophages and strongly activate downstream inflammatory cascades. We hypothesize that CFH may impact the risk of AMD by modulating oxidative stress. Here we demonstrate that CFH binds to oxPLs. The CFH 402Y variant of the protective rs1061170 genotype binds oxPLs with a higher affinity and exhibits a stronger inhibitory effect on the binding of oxPLs to retinal pigment epithelium and macrophages. In addition, plasma from non-AMD subjects with the protective genotype has a lower level of systemic oxidative stress measured by oxPLs per apolipoprotein B (oxPLs/apoB). We also show that oxPL stimulation increases expression of genes involved in macrophage infiltration, inflammation, and neovascularization in the eye. OxPLs colocalize with CFH in drusen in the human AMD eye. Subretinal injection of oxPLs induces choroidal neovascularization in mice. In addition, we show that the CFH risk allele confers higher complement activation and cell lysis activity. Together, these findings suggest that CFH influences AMD risk by modulating oxidative stress, inflammation, and abnormal angiogenesis.

Very long chain polyunsaturated fatty acid (VLC-PUFA)-containing glycerophospholipids are highly enriched in the retina; however, details regarding the specific synthesis and function of these highly unusual retinal glycerophospholipids are lacking. Elongation of very long chain fatty acids-4 (ELOVL4) has been identified as a fatty acid elongase protein involved in the synthesis of VLC-PUFAs. Mutations in ELOVL4 have also been implicated in an autosomal dominant form of Stargardt disease (STGD3), a type of juvenile macular degeneration. We have generated photoreceptor-specific conditional knock-out mice and used high performance liquid chromatography-mass spectrometry (HPLC-MS) to examine and analyze the fatty acid composition of retinal membrane glycerophosphatidylcholine and glycerophosphatidylethanolamine species. We also used immunofluorescent staining and histology coupled with electrophysiological data to assess retinal morphology and visual response. The conditional knock-out mice showed a significant decrease in retinal glycerophospholipids containing VLC-PUFAs, specifically contained in the sn-1 position of glycerophosphatidylcholine, implicating the role of Elovl4 in their synthesis. Conditional knock-out mice were also found to have abnormal accumulation of lipid droplets and lipofuscin-like granules while demonstrating photoreceptor-specific abnormalities in visual response, indicating the critical role of Elovl4 for proper rod or cone photoreceptor function. Altogether, this study demonstrates the essential role of ELOVL4 in VLC-PUFA synthesis and retinal function.

Age-related macular degeneration (AMD) is a leading cause of vision loss affecting tens of millions of elderly worldwide. Early AMD is characterized by the appearance of soft drusen, as well as pigmentary changes in the retinal pigment epithelium (RPE). These soft, confluent drusen can progress into two forms of advanced AMD: geographic atrophy (GA, or dry AMD) or choroidal neovascularization (CNV, or wet AMD). Both forms of AMD result in a similar clinical progression in terms of loss of central vision. The exact mechanism for developing early AMD, as well as triggers responsible for progressing to advanced stage of disease, is still largely unknown. However, significant evidence exists demonstrating a complex interplay of genetic and environmental factors as causes of AMD progression. Multiple genes and/or single nucleotide polymorphisms (SNPs) have been found associated with AMD, including various genes involved in the complement pathway, lipid metabolism and extracellular matrix (ECM) remodeling. Of the known genetic contributors to disease risk, the CFH Y402H and HTRA1/ARMS polymorphisms contribute to more than 50% of the genetic risk for AMD. Environmentally, oxidative stress plays a critical role in many aging diseases including cardiovascular disease, cancer, Alzheimer's disease and AMD. Due to the exposure to sunlight and high oxygen concentration, the oxidative stress burden is higher in the eye than other tissues, which can be further complicated by additional oxidative stressors such as smoking. Increasingly, evidence is accumulating suggesting that functional abnormalities of the innate immune system incurred via high risk genotypes may be contributing to the pathogenesis of AMD by altering the inflammatory homeostasis in the eye, specifically in the handling of oxidation products. As the eye in non-pathological instances maintains a low level of inflammation despite the presence of a relative abundance of potentially inflammatory molecules, we have previously hypothesized that the tight homeostatic control of inflammation via the innate immune system is likely critical for avoidance of disease progression. However, the presence of a multitude of potential triggers of inflammation results in a sensitive balance in which perturbations thereof would subsequently alter the inflammatory state of the retina, leading to a state of chronic inflammation and pathologic progression. In this review, we will highlight the background literature surrounding the known genetic and environmental contributors to AMD risk, as well as a discussion of the potential mechanistic interplay of these factors that lead to disease pathogenesis with particular emphasis on the delicate control of inflammatory homeostasis and the centrality of the innate immune system in this process.

Incomplete perifoveal posterior vitreous detachment (PVD) associated with abnormal vitreomacular adhesion (VMA) can cause vitreomacular traction (VMT) and macular hole (MH) formation, which require vitrectomy treatment. Pharmacologic vitreolysis, which is intravitreal injection with vitreolytic enzymes to resolve VMA, may be used as an alternative therapy.Ocriplasmin, formerly known as microplasmin, is a recombinant truncated form of plasmin with proteolytic activity against fibronectin and laminin.It was recently approved for VMA treatment in the European Union and USA. Phase III studies indicated that ocriplasmin injection was a safe and effective treatment for selected cases of symptomatic VMA and MH. VMA release was achieved in 26.5% of ocriplasmin-injected eyes versus 10.1% of the placebo group. MH closure was achieved in 40.6% as compared with 10.6% of the placebo group.In comparison with the outcome after vitrectomy, the success rate of ocriplasmin was still far below expectation. Ocular adverse events included vitreous floaters, photopsia and profound visual decline. Its efficacy and safety need to be further evaluated in more clinical trials.

Background: Vascular endothelial growth factor (VEGF) is upregulated by hypoxia and is a major stimulatory factor for choroidal neovascularization. The upregulation of VEGF expression in response to hypoxia occurs through hypoxia-inducible factor 1 (HIF-1), which is a transcription factor that regulates genes involved in the response to hypoxia. HIF-1 alpha is the inducible subunit of the HIF-1., Aims: To further define HIF-1 function in angiogenesis and to explore novel approaches to modulate choroidal neovascularization in age-related macular degeneration., Methods: In this study, we examined the response of human retinal pigment epithelium (RPE) cells to hypoxia and employed the small interference RNA technique to knock down gene expression of HIF-1 alpha in RPE cells., Results: We found that both the mRNA and protein levels of HIF-1 alpha in the RPE cells increased in response to hypoxia, followed by increasing expression of VEGF. Both the mRNA and protein levels of HIF-1 alpha and VEGF in the RPE cells were decreased dramatically after transfection with a HIF-1 alpha-specific small interference RNA vector., Conclusion: Our results suggest that HIF-1 may be involved in angiogenesis by controlling the expression of VEGF in vivo and provide a possible strategy for the treatment of angiogenesis by targeting the HIF-1 alpha in ischemic retinopathies., ((c) 2007 S. Karger AG, Basel.)