The high-volume synthesis of two-dimensional (2D) materials in the form of platelets is desirable for various applications. While water is considered an ideal dispersion medium, due to its abundance and low cost, the hydrophobicity of platelet surfaces has prohibited its widespread use. Here we exfoliate 2D materials directly in pure water without using any chemicals or surfactants. In order to exfoliate and disperse the materials in water, we elevate the temperature of the sonication bath, and introduce energy via the dissipation of sonic waves. Storage stability greater than one month is achieved through the maintenance of high temperatures, and through atomic and molecular level simulations, we further discover that good solubility in water is maintained due to the presence of platelet surface charges as a result of edge functionalization or intrinsic polarity. Finally, we demonstrate inkjet printing on hard and flexible substrates as a potential application of water-dispersed 2D materials.

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wileyonlinelibrary.commolecules, so GO is hydrophilic and can easily be dispersed in water. [ 2 ] The freestanding laminated GO membranes that are prepared from GO solutions can play an important role in many technological applications, including surface coatings, [ 3 ] ionic and molecular sieving, [4][5][6] hydrogen storage, [ 7,8 ] transparent and fl exible electronics, [9][10][11][12] composites, [ 13,14 ] micro-and nanoscale devices, [ 15 ] and biology and medicine. [ 16,17 ] GO papers require certain mechanical properties to provide adequate resistance to the mechanical loads and harsh environments that arise in commercial applications and must retain structural integrity over their lifetimes.Dikin et al. investigated the mechanical properties of GO papers with thicknesses varying from 2.5 to 25 µm with tensile testing. [ 2 ] Kang et al. used nano-indentation on a dynamic contact module system to measure the mechanical properties of 50-and 60-nm-thick GO fi lms. [ 18 ] Park et al. characterized the mechanical properties of one, two, and three overlapped layers of GO platelets using atomic force microscopy (AFM). [ 19 ] The Young's moduli measured with nanoresonators consisting of thin, stacked GO fi lms were found to surpass values obtained in previous measurements. [ 20 ] These results suggest that the mechanical properties of GO fi lms or papers, such as stiffness and fracture strength, might vary with thickness; however, no systematic study of this issue has been carried out to date.Graphene oxide (GO) papers are candidates for structural materials in modern technology due to their high specifi c strength and stiffness. The relationship between their mechanical properties and structure needs to be systematically investigated before they can be applied to the broad range fi elds where they have potential. Herein, the mechanical properties of GO papers with various thicknesses (0.5-100 µm) are investigated using bulge and tensile test methods; this includes the Young's modulus, fracture strength, fracture strain, and toughness. The Young's modulus, fracture strength, and toughness are found to decrease with increasing thickness, with the fi rst two exhibiting differences by a factor of four. In contrast, the fracture strain slightly increases with thickness. Transmission electron, scanning electron, and atomic force microscopy indicate that the mechanical properties vary with thickness due to variations in the inner structure and surface morphology, such as crack formation and surface roughness. Thicker GO papers are weaker because they contain more voids that are produced during the fabrication process. Surface wrinkles and residual stress are found to result in increased fracture strain. Determination of this structure-property relationship provide improved guidelines for the use of GO-based thin-fi lm materials in mechanical structures.

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We present a case of bilateral serous retinal detachment (SRD) as a presenting sign of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). A 45-year-old woman presented with decreased vision and was found to have bilateral serous retinal detachment. Peripheral blood smears revealed leukocytosis of 53.9×103/µL with 64.6% lymphoblasts. A bone marrow aspirate revealed the presence of lymphoblasts. Cytogenetic and molecular genetic analysis detected a reciprocal translocation between chromosome 9 and 22, t(9;22) (q34;q11). A diagnosis of Ph+ ALL was made. Following systemic chemotherapy, the bilateral SRD resolved completely with full recovery of vision. The sudden appearance of SRD should raise suspicion for leukemia. Prompt recognition of this disease is important for early systemic treatment and restoration of visual function.

Reactive oxygen species are involved in ovulation. The aim of this study was to examine gonadotropin regulation of antioxidant enzyme sulfiredoxin (Srx) and peroxiredoxin 2 (PRDX2) expressions and modification during the ovulatory process in rats. Administration of antioxidants in vivo reduced ovulation rate and cumulus expansion. LH treatment increased H(2)O(2) levels within 15 min, which, in turn, induced Srx gene expression in cultured preovulatory follicles. Treatment of preovulatory follicles with catalase suppressed the stimulatory effect of LH on Akt phosphorylation. LH- or H(2)O(2)-stimulated Srx mRNA levels were suppressed by inhibitors of antioxidant agents and MAPK kinase. An in vivo injection of equine chorionic gonadotropin-human chorionic gonadotropin (hCG) stimulated Srx mRNA within 1 h in granulosa but not thecal cells of preovulatory follicles. Srx protein levels were stimulated from 3 h post-hCG injection. Immunofluorescence analysis revealed that oocytes expressed the Srx protein. Furthermore, hCG treatment increased Srx expression in mural granulosa, theca and cumulus cells, but the Srx protein was not detected in corpora lutea. Gene expression of PRDX2, identified as an Srx-dependent modified enzyme, was stimulated by gonadotropins. In situ hybridization analysis demonstrated that PRDX2 mRNA was detected in oocytes and theca cells as well as granulosa cells of some antral and preovulatory follicles. High levels of PRDX2 mRNA were detected in corpora lutea. Total levels of PRDX2 protein were not changed by gonadotropins. However, levels of hyperoxidized PRDX2 increased within 2-3 h after the hCG injection. Taken together, gonadotropin stimulation of Srx expression and PRDX2 modification in the ovary suggest the existence of an antioxidant system to maintain H(2)O(2) production and elimination during the periovulatory period.

We report three cases of neovascular glaucoma secondary to central retinal artery occlusion (CRAO) which were effectively managed with intravitreal bevacizumab (IVB) followed by panretinal photocoagulation (PRP). Neovascular glaucoma without peripheral anterior synechiae developed between one and five weeks following CRAO onset. All patients received 0.75 mg (0.03 ml) IVB. In all patients, complete regression of the iris and anterior chamber angle neovascularization was confirmed within one week. PRP was applied two weeks after the injection. The follow-up period was four to seven months (average, five months). Intraocular pressure was controlled in all patients using topical antiglaucoma medications alone. However, one patient experienced a recurrence of neovascularization three months after the initial combination treatment. This patient received another IVB injection and additional PRP, and the recurrent neovascularization resolved. There were no local or systemic adverse events in any patients. Therefore, intravitreal bevacizumab may be an effective adjunct in the treatment of neovascular glaucoma associated with CRAO.