Chemical Route to Twisted Graphene, Graphene Oxide and Boron Nitride.

The recently discovered twisted graphene has attracted considerable interest. A simple chemical route was found to prepare twisted graphene by covalently linking layers of exfoliated graphene containing surface carboxyl groups with an amine-containing linker (trans-1,4-diaminocyclohexane). The twisted graphene shows the expected selected area electron diffraction pattern with sets of diffraction spots out with different angular spacings, unlike graphene, which shows a hexagonal pattern. Twisted multilayer graphene oxide could be prepared by the above procedure. Twisted boron nitride, prepared by cross-linking layers of boron nitride (BN) containing surface amino groups with oxalic acid linker, exhibited a diffraction pattern comparable to that of twisted graphene. First-principles DFT calculations threw light on the structures and the nature of interactions associated with twisted graphene/BN obtained by covalent linking of layers.

0-D and 1-D Perovskite-like Hybrid Bismuth(III) Iodides.

Low-dimensional hybrid bismuth halide perovskites have recently emerged as a class of non-toxic alternative to lead perovskites with promising optoelectronic properties. Here, we report three hybrid bismuth(III)-iodides: 0-D (H2DAC)2Bi2I10 ⋅ 6H2O (H2DAC_Bi_I), 0-D (H2DAF)4Bi2I10 ⋅ 2I3 ⋅ 2I ⋅ 6H2O (H2DAF_Bi_I), and 1-D (H2DAP)BiI5 (H2DAP_Bi_I) (where H2DAC=trans-1,4-diammoniumcyclohexane; H2DAF=2,7-diammoniumfluorene and H2DAP=1,5-diammoniumpentane). Their synthesis, single-crystal X-ray structures, and photophysical properties are reported. The first two compounds comprise edge-sharing [Bi2I10]4- dimers, while the last compound has cis-corner-sharing 1-D chains of [BiI6]3- octahedra. Intercalation of triiodide (I3 -) and iodide (I-) ions enhance electronic coupling between the [Bi2I10]4- of H2DAF_Bi_I, leading to enhanced optical absorption, compared to H2DAC_Bi_I which lacks such intercalants. Furthermore, calorimetric and variable temperature X-ray diffraction measurements suggest a centrosymmetric to non-centrosymmetric phase transition (monoclinic P212121↔orthorhombic Pnma) of H2DAP_Bi_I at 448 K (in heating step) and at 443 K (in cooling step).

High-Flux lamellar MoSe2 membranes for efficient dye/salt separation.

Membrane-based technology is emerging as an efficient technique for wastewater treatment in recent years. Membranes made up of two-dimensional materials provide high selectivity and water flux compared to conventional polymeric membranes. Herein, we report the synthesis and use of MoSe2 membrane for dye and drug separation in wastewater, mainly from textile and pharmaceutical industries. The as-prepared MoSe2 membrane shows âˆ¼ 100% rejection for organic dyes and ciprofloxacin drug with a water flux reaching up to âˆ¼ 900 Lm-2h-1bar-1. Further, the MoSe2 membrane shows lower NaCl rejection of âˆ¼ 1.9% for the dye/salt mixture. The interlayer spacing in the MoSe2 membrane allows the water molecules and ions from the salt to pass through freely but restricts the movement of large contaminants. The membrane is stable against the bovine albumin serum fouling with a flux recovery rate of 96%. It also shows good performance even in harsh environments (pH 3-10). To the best of our knowledge, the MoSe2 membranes were fabricated for the first time for wastewater treatment application. The dye/salt separation performance of the MoSe2 membrane is significantly better than several other membranes. This work highlights the promising potential for using two-dimensional materials for textile and pharmaceutical wastewater treatment.

Safe Use of Epidural Analgesia in a Parturient With Spinocerebellar Ataxia: A Case Report.

A 28-year-old, gravida 7, para 4 woman with medical history of sickle cell trait presented to labor and delivery at 39 weeks of gestation for rupture of membranes. The patient had a history of suspected spinocerebellar ataxia with incomplete workup before the current admission. The patient requested epidural analgesia for labor. Epidural was placed at L3-L4 interspace without any complications and the rest of the labor was uneventful. Magnetic resonance imaging of the brain was performed after the delivery and the diagnosis of spinocerebellar ataxia was confirmed. The patient's neurological status remained stable after the procedure.

Metyrapone alleviates deleterious effects of maternal food restriction on lung development and growth of rat offspring.

Maternal food restriction (MFR) causes intrauterine growth restriction, a known risk factor for developing chronic lung disease. However, it is unknown whether this negative outcome is gender specific or preventable by blocking the MFR-induced hyperglucocorticoidism. Using a well-established rat model, we used metyrapone (MTP), an inhibitor of glucocorticoid synthesis, to study the MFR-induced lung changes on postnatal day (p) 21 in a gender-specific manner. From embryonic day 10 until delivery, pregnant dams were fed either an ad libitum diet or a 50% caloric restricted diet with or without MTP supplementation. Postnatally, the offspring were fed ad libitum from healthy dams until p21. Morphometric, Western blot, and immunohistochemical analysis of the lungs demonstrated that MTP mitigated the MFR-mediated decrease in alveolar count, decrease in adipogenic protein peroxisome proliferator-activated receptor γ, increase in myogenic proteins (fibronectin, α-smooth muscle actin, and calponin), increase in Wnt signaling intermediates (lymphoid enhancer-binding factor 1 and ß-catenin), and increase in glucocorticoid receptor (GR) levels. The MFR-induced lung phenotype and the effects of MTP were similar in both genders. To elucidate the mechanism of MFR-induced shift of the adipogenic-to-myogenic phenotype, lung fibroblasts were used to independently study the effects of (1) nutrient restriction and (2) excess steroid exposure. Nutrient deprivation increased myogenic proteins, Wnt signaling intermediates, and GR, all changes blocked by protein supplementation. MTP also blocked, likely by normalizing nicotinamide adenine dinucleotide phosphate levels, the corticosterone-induced increase in myogenic proteins, but had no effect on GR levels. In summary, protein restriction and increased glucocorticoid levels appear to be the key players in MFR-induced lung disease, affecting both genders.

Metyrapone blocks maternal food restriction-induced changes in female rat offspring lung development.

Maternal food restriction (MFR) during pregnancy affects pulmonary surfactant production in the intrauterine growth-restricted (IUGR) offspring through unknown mechanisms. Since pulmonary surfactant production is regulated by maternal and fetal corticosteroid levels, both known to be increased in IUGR pregnancies, we hypothesized that metyrapone (MTP), a glucocorticoid synthesis inhibitor, would block the effects of MFR on surfactant production in the offspring. Three groups of pregnant rat dams were used (1) control dams fed ad libitum; (2) MFR (50% reduction in calories) from days 10 to 22 of gestation; and (3) MFR + MTP in drinking water (0.5 mg/mL), days 11 to 22 of gestation. At 5 months, the MFR offspring weighed significantly more, had reduced alveolar number, increased septal thickness, and decreased surfactant protein and phospholipid synthesis. These MFR-induced effects were normalized by the antiglucocorticoid MTP, suggesting that the stress of MFR causes hypercorticoidism, altering lung structure and function in adulthood.