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In this paper, the mechanical performance improvement of traditional penetration mortise–tenon (PMT) connections reinforced by self-tapping screws (STSs) were experimental and numerical studied. Four unreinforced penetration mortise–tenon connections and four STS-reinforced connections were experimentally investigated under monotonic and low-frequency cyclic loading. Besides, the numerical model of PMT connections reinforced by STSs with different diameters and yield strength were established and analyzed.Their failure modes, rotational stiffness, moment-resisting capacity, ductility, and seismic behavior were studied. The experimental results indicated that the STSs reinforcements could enhance the moment-resisting capacity of the penetration mortise–tenon connection. Compared with unreinforced connections, the initial stiffness of STS-reinforced connections increased by 75% with the moment-resisting capacity increasing by 69%, respectively. Furthermore, the STSs reinforcement method can effectively restrict the pull-out of tenon during the whole loading process. Numerical simulation results showed that the yield strength of STS has little effect on the moment-bearing behavior of the connection. The diameter of STS significantly influences the connection performance, and the diameter of 8 mm is suggested.

Letter to the Editor

The diversity of stain fungi is important if wood is inhabited with various fungi, and the discoloration mechanism will be better understood. MiSeq amplicon high-throughput sequencing (Illumina®) is able to detect species richness (the number of species within a community) and species evenness (the sizes of species populations within a community). This study detected fungal diversity in discolored Mongolian pine for the first time by the MiSeq approach, focusing on the nuclear ribosomal internal transcribed spacer-1 (ITS1). The results show that the discolored wood was inhabited by a combination of microorganisms, more than 90% of which belong toAscomycotafungi at the phylum level. The MiSeq method revealed not only all the inhabited fungal species but also their quantitative relation to each other. The dominant fungal species in sample A areHelotiales(34.1%) andHypocreales(20.7%). The dominant fungal species in sample B isNectriaceae(67.9%), whileHypocrea(34.7%) andSporothrix(27.6%) are the dominant fungal species in sample C. It was confirmed via core microbiome analysis that the following fungi were common stain fungi in the three discolored samples:Fusariumspp.,Aspergillusspp.,Sporothrixspp.,Penicilliumspp.,Trichodermaspp.,Alternariaspp. andCladophialophoraspp.

The roles of angiogenesis in development, health, and disease have been studied extensively; however, the studies related to lymphatic system are limited due to the difficulty in observing colorless lymphatic vessels. But recently, with the improved technique, the relative importance of the lymphatic system is just being revealed. We bred transgenic mice in which lymphatic endothelial cells express GFP (Prox1-GFP) with mice in which vascular endothelial cells express DsRed (Flt1-DsRed) to generate Prox1-GFP/Flt1-DsRed (PGFD) mice. The inherent fluorescence of blood and lymphatic vessels allows for direct visualization of blood and lymphatic vessels in various organs via confocal and two-photon microscopy and the formation, branching, and regression of both vessel types in the same live mouse cornea throughout an experimental time course. PGFD mice were bred with CDh5CreERT2 and VEGFR2lox knockout mice to examine specific knockouts. These studies showed a novel role for vascular endothelial cell VEGFR2 in regulating VEGFC-induced corneal lymphangiogenesis. Conditional deletion of vascular endothelial VEGFR2 abolished VEGFA- and VEGFC-induced corneal lymphangiogenesis. These results demonstrate the potential use of the PGFD mouse as a powerful animal model for studying angiogenesis and lymphangiogenesis.

AIM: To observe the shifting hierarchy of the conjunctival florae in the patients who employed a long-time topical fluoroquinolone and characterize the consequent variations of their antibiotic sensitivity and virulence. METHODS: A total of 143 eyes (143 patients) who suffered from the non-infectious corneal ulcer and topically used fluoroquinolone more than 2wk were enrolled as the fluoroquinolone eye. The untreated fellow eye was considered as the contralateral eye. Seventy-five healthy subjects were selected as the control. The culture positivity and strains of the isolated conjunctival florae were observed. Their antibiotic susceptibility and expression of the virulence-related genes were detected. RESULTS: Florae were recovered from 84.0%, 37.1%, and 57.3% of the conjunctival swabs in the control, fluoroquinolone eye, and contralateral eye, respectively. The most frequently isolated microorganisms were Staphylococcus epidermidis (34.9%) in the control, followed by Staphylococcus aureus (17.5%), Staphylococcus saprophyticus (14.3%), Micrococcus (9.5%), Propionibacterium acnes (7.9%). However, those orderly ranks shifted to Staphylococcus aureus (34.0%), Propionibacterium acnes (20.8%), Candida albicans (17.0%), Pseudomonas aeruginosa (9.4%) in the fluoroquinolone eye. A growing number of the fluoroquinolone-resistant florae survived in the fluoroquinolone eye, accompanied by an increased expression of the virulence-related genes. CONCLUSION: A long-time topical fluoroquinolone leads to a shifting hierarchy of the conjunctival florae, accompanied by the consequent variations of the antibiotic sensitivity and virulence.

Purpose To explore the correlation of tear and conjunctival cytokines and sensory hypersensitivity in mild dry eye (MDE) patients characterized by symptoms outweighing signs (DESOS). Methods The subjects comprised 39 patients with MDE characterized by DESOS, 18 patients with common MDE (CMDE), and 15 healthy controls. The patients with DESOS were randomly subdivided into two groups; the C-DESOS group received artificial tears only, and the G-DESOS group received artificial tears and 0.1% fluorometholone eye drops three times a day. Symptoms were assessed using the Ocular Surface Disease Index (OSDI) and the Neuropathic Pain Symptoms Inventory modified for Eye (NPSI-E) questionnaire. Ocular examinations and in vivo confocal microscopy (IVCM) were also employed. Tear and conjunctival cytokines were measured using Multiplex or RT–PCR on Days 0, 7, and 30. The correlation between the expression of cytokines and hypersensitivity status was analyzed. Results Compared with the CMDE and control groups, the DESOS groups showed a significant increase in symptom scores and in the ratio of symptoms versus signs. IL-1 β, IL-2, IL-6, and TNF-α in tears and conjunctiva increased in the DESOS groups compared to the CMDE and control groups, indicating a high correlation with hypersensitivity status in the DESOS groups. Glucocorticoid treatment significantly decreased the level of cytokines in tears and conjunctiva in the G-DESOS group and subsequently ameliorated the symptoms. Conclusions Tear and conjunctival cytokines, including IL-1 β, IL-2, IL-6, and TNF-α, were correlated with sensory hypersensitivity status in the DESOS groups, suggesting they play an important role in the discordance of symptoms outweighing signs.

Background::Lymphatic vessel formation (lymphangiogenesis) plays important roles in cancer metastasis, organ rejection, and lymphedema, but the underlying molecular events remain unclear. Furthermore, despite significant overlap in the molecular families involved in angiogenesis and lymphangiogenesis, little is known about the crosstalk between these processes. The ex vivo aortic ring assay and lymphatic ring assay have enabled detailed studies of vessel sprouting, but harvesting and imaging clear thoracic duct samples remain challenging. Here we present a modified ex vivo dual aortic ring and thoracic duct assay using tissues from dual fluorescence reporter Prox1- GFP/Flt1-DsRed (PGFD) mice, which permit simultaneous visualization of blood and lymphatic endothelial cells.Objective::To characterize the concurrent sprouting of intrinsically fluorescent blood and lymphatic vessels from harvested aorta and thoracic duct samples.Methods::Dual aorta and thoracic duct specimens were harvested from PGFD mice, grown in six types of endothelial cell growth media (one control, five that each lack a specific growth factor), and visualized by confocal fluorescence microscopy. Linear mixed models were used to compare the extent of vessel growth and sprouting over a 28-day period.Results::Angiogenesis occurred prior to lymphangiogenesis in our assay. The control medium generally induced superior growth of both vessel types compared with the different modified media formulations. The greatest decrease in lymphangiogenesis was observed in vascular endothelial growth factor-C (VEGF-C)-devoid medium, suggesting the importance of VEGF-C in lymphangiogenesis.Conclusion::The modified ex vivo dual aortic ring and thoracic duct assay represents a powerful tool for studying angiogenesis and lymphangiogenesis in concert.

To observe the effect of DMEM/F12 pegylated with methoxy polyethylene glycol succinimidyl propionate (mPEG-SPA) on the biophysical and immune characteristics of the rat cornea preserved in it. Corneal grafts were harvested from Wistar rat and preserved in the DMEM/F12 plus mPEG-SPA, DMEM/F12 without mPEG-SPA, and standard Optisol-GS solution at 4 °C for 14 days, referred as plus-PEG, minus-PEG, and Optisol grafts, respectively. The biophysical properties of those grafts, including transmittance, thickness, water content, and biomechanics were investigated. The survival of those grafts was observed in the high-risk corneal transplantation model. Transmittance and biomechanics did not show any differences among those grafts. Thickness and water content of plus-PEG grafts were slightly improved. Proliferation and activation of lymphocytes were lower while they were incubated with plus-PEG grafts, compared with minus-PEG grafts and Optisol grafts. The mean survival time was significantly prolonged in plus-PEG grafts. DMEM/F12 solution plus mPEG-SPA improved the survival of corneal grafts and maintained the comparative biophysical characteristics of them, compared with the standard preservation solution.

We investigated the immune camouflage effects of methoxy polyethylene glycol succinimidyl propionate (mPEG-SPA) on corneal antigens and explored a novel approach for reducing corneal antigenicity, thereby decreasing corneal graft rejection. Importantly, this approach did not alter normal local immunity. Corneal grafts were treated with mPEG-SPA 5KD or 20KD (3% W/V), which could shield major histocompatibility antigen class I molecules (RT1-A) of corneal grafts. Skin grafts of Wistar rats were transplanted to SD rats. Then the splenic lymphocytes were isolated from SD rats. Subsequently, the lymphocytes were co-cultured with autologous corneal grafts or untreated corneal grafts and PEGylated grafts treated with mPEG-SPA 5KD or 20KD obtained from the counterpart skin donors, which were used as autologous control, allogeneic control, mPEG-SPA 5KD group and mPEG-SPA 20KD group, respectively. Lymphocyte proliferation was lower in mPEG-SPA 5KD group and mPEG-SPA 20KD group than in the allogeneic control. SD rats with corneal neovascularisation were used as recipients for high-risk corneal transplantation and were randomly divided into four groups: autologous control, allogeneic control, mPEG-SPA 5KD group and mPEG-SPA 20KD group. The recipients received corneal grafts from Wistar rats. Corneal graft survival was prolonged and graft rejection was reduced in the mPEG-SPA 5KD group and the mPEG-SPA 20KD group compared to the allogeneic control. Thus, we think that mPEG-SPA could immunologically camouflage corneal antigens to prolong corneal grafts survival in high-risk transplantation.

Background Immunohistochemical staining experiments have shown that both hemangiogenesis and lymphangiogenesis occur following severe corneal and conjunctival injury and that the neovascularization of the cornea often has severe visual consequences. To better understand how hemangiogenesis and lymphangiogenesis are induced by different degrees of ocular injury, we investigated patterns of injury-induced corneal neovascularization in live Prox1-GFP/Flk1::myr-mCherry mice, in which blood and lymphatic vessels can be imaged simultaneously in vivo. Methods The eyes of Prox1-GFP/Flk1::myr-mCherry mice were injured according to four models based on epithelial debridement of the: A) central cornea (a 1.5-mm-diameter circle of tissue over the corneal apex), B) total cornea, C) bulbar conjunctiva, and D) cornea + bulbar conjunctiva. Corneal blood and lymphatic vessels were imaged on days 0, 3, 7, and 10 post-injury, and the percentages of the cornea containing blood and lymphatic vessels were calculated. Results Neither central corneal nor bulbar conjunctival debridement resulted in significant vessel growth in the mouse cornea, whereas total corneal and corneal + bulbar conjunctival debridement did. On day 10 in the central cornea, total cornea, bulbar conjunctiva, and corneal + bulbar conjunctival epithelial debridement models, the percentage of the corneal surface that was occupied by blood vessels (hemangiogenesis) was 1.9 ± 0.8%, 7.14 ± 2.4%, 2.29 ± 1%, and 15.05 ± 2.14%, respectively, and the percentage of the corneal surface that was occupied by lymphatic vessels (lymphangiogenesis) was 2.45 ± 1.51%, 4.85 ± 0.95%, 2.95 ± 1.27%, and 4.15 ± 3.85%, respectively. Conclusions Substantial corneal debridement was required to induce corneal neovascularization in the mouse cornea, and the corneal epithelium may therefore be partially responsible for maintaining corneal avascularity. General significance Our study demonstrates that GFP/Flk1::myr-mCherry mice are a useful model for studying coordinated hemangiogenic and lymphangiogenic responses.

Purpose To describe a surgical technique for repair of an intractable sclerocorneal melt caused by a serious chemical burn. Methods This study includes a technique description and review of 3 representative cases. Results The combination of tenonplasty with a free oral buccal mucosa autograft was used in 3 patients with sclerocorneal melts caused by chemical burns. Promising results were found in each of them. The area of the sclerocorneal melt healed successfully after surgery, and the integrities of the eyeballs were salvaged. Conclusions This technique provides a new method for surgical repair of an intractable sclerocorneal melt caused by a chemical burn.

To report a palliative and alternative surgical procedure, allogeneic sclera graft combined with autologous conjunctival flap (ASGACF), employing to repair the large emergent corneal perforation. The detail protocol of the surgical procedure was characterized and four representative cases were reviewed. An allogeneic sclera graft and recipient bed were prepared as the traditional penetrating keratoplasty (PK). And then sutured the sclera graft to the bed with 10-0 nylon suture and covered with a pedicled autologous conjunctival flap in half size. In the follow-up, the ASGACF repaired all of the corneal perforations and restored the integral walls of eyeballs, in spite of one who underwent a second surgery. This surgical procedure provided a palliative method to repair the large emergent corneal perforation while there is the lack of a corneal graft.