The strength curves of lightweight aggregate concrete （LWAC） were tested based on detecting LWAC with density of 1 400-1 900 kg/m3 and LWAC with strength grade of LC15-LC50 by rebound method and ...ultrasonic-rebound combined method.The results show that the common measured strength curves tested by above two methods can not satisfy the required accuracy of LWAC strength test.In addition,specified compressive strength curves of testing LWAC by rebound method and ultrasonic-rebound combined method are obtained,respectively.
The thorough degeneration of organelles in the core of the lens is certainly a hallmark event during the lens development. Organelles degradation in the terminal differentiation process of lens fiber ...cells to form an organelle-free zone is critical for lens maturation and transparency. Several mechanisms have been proposed to expand our understanding of lens organelles degradation, including apoptotic pathways, the participation of ribozyme, proteolytic enzyme and phospholipase A and acyltransferase, and the newly discovered roles for autophagy. Autophagy is a lysosome-dependent degradation reaction during which the “useless” cellular components are degraded and recycled. These cellular components, such as incorrectly folded proteins, damaged organelles and other macromolecules, are first engulfed by the autophagosome before being further delivered to lysosomes for degradation. Although autophagy has been recognized involving in organelle degradation of the lens, the detailed functions remain to be discovered. Recent advances have revealed that autophagy not only plays a vital role in the intracellular quality control of the lens but is also involved in the degradation of nonnuclear organelles in the process of lens fiber cell differentiation. Herein, we first review the potential mechanisms of organelle-free zone formation, then discuss the roles of autophagy in intracellular quality control and cataract formation, and finally substantially summarize the potential involvement of autophagy in the development of organelle-free zone formation.
Purpose
Calculating the intraocular lens (IOL) power in short eyes for cataract surgery has been a challenge. A meta-analysis was conducted to identify, among several classic and new IOL power ...calculation formulae, which obtains the best accuracy.
Methods
All studies aiming at comparing the accuracy of IOL power calculation formulae in short eyes were searched up in the databases of PubMed, EMBASE, Web of Science and the Cochrane library from Jan. 2011 to Mar. 2021. Primary outcomes were the percentages of eyes with a refractive prediction error in ± 0.25D, ± 0.5D and ± 1.0D.
Results
Totally 1,476 eyes from 14 studies were enrolled in comparison of 13 formulae (Barrett Universal II, Castrop, Haigis, Hoffer Q, Holladay1, Holladay2, Kane, Ladas Super Formula, Okulix, Olsen, Pearl-DGS, SRK/T and T2). Pearl-DGS had the highest percentage within ± 0.25D. In the ± 0.5D range, Pearl-DGS obtained the highest percentage again, and it was significantly higher than Barrett Universal II, Haigis, Hoffer Q, Holladay1, Holladay2 and Olsen (
P
= 0.001,
P
= 0.02,
P
= 0.0003,
P
= 0.01,
P
= 0.007,
P
= 0.05, respectively). In the ± 1.0D range, Okulix possessed the highest percentage, and it was significantly higher than Barrett Universal II, Castrop, Hoffer Q and Holladay2 (
P
= 0.0005,
P
= 0.03,
P
= 0.003,
P
= 0.02, respectively).
Conclusion
The new generation formulae, based on artificial intelligence or ray-tracing principle, are more accurate than the convergence formulae. Pearl-DGS and Okulix are the two most accurate formulae in short eyes.
Besides the cognitive impairment and degeneration in the brain, vision dysfunction and retina damage are always prevalent in patients with Alzheimer's disease (AD). The uncompetitive antagonist of ...the N-methyl-d-aspartate receptor, memantine (MEM), has been proven to improve the cognition of patients with AD. However, limited information exists regarding the mechanism of neurodegeneration and the possible neuroprotective mechanisms of MEM on the retinas of patients with AD. In the present study, by using APPswe/PS1ΔE9 double transgenic (dtg) mice, we found that MEM rescued the loss of retinal ganglion cells (RGCs), as well as improved visual impairments, including improving the P50 component in pattern electroretinograms and the latency delay of the P2 component in flash visual evoked potentials of APPswe/PS1ΔE9 dtg mice. The activated microglia in the retinas of APPswe/PS1ΔE9 dtg mice were also inhibited by MEM. Additionally, the level of glutamine synthetase expressed by Müller cells within the RGC layer was upregulated in APPswe/PS1ΔE9 dtg mice, which was inhibited by MEM. Simultaneously, MEM also reduced the apoptosis of choline acetyl transferase-immunoreactive cholinergic amacrine cells within the RGC layer of AD mice. Moreover, the phosphorylation level of extracellular regulated protein kinases 1 and 2 was increased in APPswe/PS1ΔE9 dtg mice, which was blocked by MEM treatment. These findings suggest that MEM protects RGCs in the retinas of APPswe/PS1ΔE9 dtg mice by modulating the immune response of microglia and the adapted response of Müller cells, making MEM a potential ophthalmic treatment alternative in patients with AD.
•Memantine could rescue the loss of RGCs in AD transgenic mice's retina.•Interaction of Müller cells, microglia and amarcine cells played role in AD retina.•Memantine modulated interactions of microglia and Müller cells in AD retina.•The immunomodulating mechanism of memantine was mediated via ERK1/2 pathway.
Currently, the use of assisted reproductive technology (ART) is increasing. Because of the poor prognosis of retinopathy of prematurity (ROP), the association between ART and the ROP has been ...explored in several studies, but the result was still inconclusive. Conducting a meta-analysis, we evaluated the risk of ROP in relation to the ART. Subgroup analysis as well as groups with different embryo numbers and different ROP stages was further analyzed. The PubMed, Embase, and Cochrane Library databases were searched for studies recording data about both the use of ART and ROP occurrence simultaneously. Odds ratios (ORs) and 95% confidence interval (95%CI) were calculated to analyze the association by using random- or fixed-effect models based on heterogeneity test. In total 15 observational studies containing 10392 ART cases and 39474 spontaneous conception cases were included. Results showed that there was a significant association between the use of ART and ROP occurrence in the offspring (OR = 1.34, 95% CI: 1.05 to 1.73, P = 0.02). With subgroup analysis, we found that the influence actually came from a subgroup of ART, the in vitro fertilization (IVF). Moreover, there was a significant association between ART and ROP in singletons. Though insignificant, the ORs were larger than 1 in the analysis between ART and stage 1 and 2 ROP. But ART showed significant association with stage 3 ROP. Our study preliminarily indicated that the use of IVF was associated with higher risk of ROP occurrence. And ART is more likely to result in severe ROP and ROP in singletons. Further specific, high-quality studies with large sample size are still needed to draw more precise conclusion.
Retinopathy is one of the main causes of blindness worldwide. Investigating its pathogenesis is essential for the early diagnosis and timely treatment of retinopathy. Unfortunately, ethical barriers ...hinder the collection of evidence from humans. Recently, numerous studies have shown that human pluripotent stem cells (PSCs) can be differentiated into retinal organoids (ROs) using different induction protocols, which have enormous potential in retinopathy for disease modeling, drug screening, and stem cell-based therapies. This study describes an optimized induction protocol to generate neural retina (NR) that significantly reduces the probability of vesiculation and fusion, increasing the success rate of production until day 60. Based on the ability of PSCs to self-reorganize after dissociation, combined with certain complementary factors, this new method can specifically drive NR differentiation. Furthermore, the approach is uncomplicated, cost-effective, exhibits notable repeatability and efficiency, presents encouraging prospects for personalized models of retinal diseases, and supplies a plentiful cell reservoir for applications such as cell therapy, drug screening, and gene therapy testing.
Ethanol (EtOH) exposure during early postnatal life triggers obvious neurotoxic effects on the developing hippocampus and results in long-term effects on hippocampal neurogenesis. Resveratrol (RSV) ...has been demonstrated to exert potential neuroprotective effects by promoting hippocampal neurogenesis. However, the effects of RSV on the EtOH-mediated impairment of hippocampal neurogenesis remain undetermined. Thus, mice were pretreated with RSV and were later exposed to EtOH to evaluate its protective effects on EtOH-mediated toxicity during hippocampal development. The results indicated that a brief exposure of EtOH on postnatal day 7 resulted in a significant impairment in hippocampal neurogenesis and a depletion of hippocampal neural precursor cells (NPCs). This effect was attenuated by pretreatment with RSV. Furthermore, EtOH exposure resulted in a reduction in spine density on the granular neurons of the dentate gyrus (DG), and the spines exhibited a less mature morphological phenotype characterized by a higher proportion of stubby spines and a lower proportion of mushroom spines. However, RSV treatment effectively reversed these responses. We further confirmed that RSV treatment reversed the EtOH-induced down-regulation of hippocampal pERK and Hes1 protein levels, which may be related to the proliferation and maintenance of NPCs. Furthermore, EtOH exposure in the C17.2 NPCs also diminished cell proliferation and activated apoptosis, which could be reversed by pretreatment of RSV. Overall, our results suggest that RSV pretreatment protects against EtOH-induced defects in neurogenesis in postnatal mice and may thus play a critical role in preventing EtOH-mediated toxicity in the developing hippocampus.
•RSV prevented the deleterious effects of EtOH on hippocampal neurogenesis.•RSV prevented the EtOH-induced reduction in the pool of NPCs in the DG.•RSV pretreatment reversed EtOH-induced down-regulation of hippocampal pERK and Hes1.•RSV pretreatment reversed EtOH-induced inhibition of proliferation in the C17.2 NPCs.
The vertebrate retina is a highly multilayered nervous tissue with a large diversity of cellular components. With the development of stem cell technologies, human retinas can be generated in ...three-dimensional (3-D) culture in vitro. However, understanding the factors modulating key productive processes and the way that they influence development are far from clear. Oxygen, as the most essential element participating in metabolism, is a critical factor regulating organic development. In this study, using 3-D culture of human stem cells, we examined the effect of intermittent high oxygen treatment (40% O2) on the formation and cellular behavior of neural retinas (NR) in the embryonic body (EB). The volume of EB and number of proliferating cells increased significantly under 40% O2 on day 38, 50, and 62. Additionally, the ratio of PAX6+ cells within NR was significantly increased. The neural rosettes could only develop with correct apical-basal polarity under 40% O2. In addition, the generation, migration and maturation of retinal ganglion cells were enhanced under 40% O2. All of these results illustrated that 40% O2 strengthened the formation of NR in EB with characteristics similar to the in vivo state, suggesting that the hyperoxic state facilitated the retinal development in vitro.
The influence of thaumasite formation on the performance of Portland-limestone cement concrete stored in magnesium sulfate solution was studied. The experimental results show that the deterioration ...of Portland-limestone cement concrete is higher than that of Portland cement concrete. The more the content of limestone, the more serious the deterioration of concrete, and also the lower the temperature, the earlier the deterioration of concrete. Thaumasite was detected to form in the Portland-limestone pastes when stored in 10wt% MgSO^sub 4^ solution at 3-10°C and it was easy to form at lower temperatures.PUBLICATION ABSTRACT
DNA methylation, an epigenetic mechanism used by cells to control gene expression, has an important biological role in plant development and environmental fitness. Since plant DNA methylation is ...closely related to environmental conditions, variation during the day is expected. Here, in genetically identical plants of Populus nigra clone N46, DNA methylation changes in leaves over a 24 h period were detected using the methylation-sensitive amplification polymorphism method. The results showed different DNA methylation patterns in mature poplar leaves: not only in individuals at the same time, but also in samples at each of the six time during the day. In addition,night samples had a higher percentage of methylation than in morning samples. However, no statistically significant differences were found among the samples gathered at different times. Similar results were obtained for three other P. nigra clones with different genetic backgrounds.Real time qPCR showed that the DNA methyltransferase genes Pt-MET1 and Pt-SOM1 involved in CG DNA methylation in poplar were stable over a 24 h period in leaves of P. nigra N46 compared with circadian-controlled genes. That could be part of the reason that methylation of CCGG sites is stable in those leaves. That DNA methylation differed even in genetically identical plants indicates the specificity of DNA methylation changes in their genomes.No statistically significant differences in methylation changes were found between day and night, suggesting that DNA methylation is more stable than expected and is unlikely to be involved in circadian regulation in plants.
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