Interlayer excitons in MoSe2/2D perovskite hybrid heterostructures - the interplay between charge and energy transfer.

van der Waals crystals have opened a new and exciting chapter in heterostructure research, removing the lattice matching constraint characteristics of epitaxial semiconductors. They provide unprecedented flexibility for heterostructure design. Combining two-dimensional (2D) perovskites with other 2D materials, in particular transition metal dichalcogenides (TMDs), has recently emerged as an intriguing way to design hybrid opto-electronic devices. However, the excitation transfer mechanism between the layers (charge or energy transfer) remains to be elucidated. Here, we investigate PEA2PbI4/MoSe2 and (BA)2PbI4/MoSe2 heterostructures by combining optical spectroscopy and density functional theory (DFT) calculations. We show that band alignment facilitates charge transfer. Namely, holes are transferred from TMDs to 2D perovskites, while the electron transfer is blocked, resulting in the formation of interlayer excitons. Moreover, we show that the energy transfer mechanism can be turned on by an appropriate alignment of the excitonic states, providing a rule of thumb for the deterministic control of the excitation transfer mechanism in TMD/2D-perovskite heterostructures.

Efficacy and safety of a new surgical method to treat malignant glaucoma in pseudophakia.

PURPOSE: To assess the efficacy and safety of a relatively new surgical method in pseudophakic malignant glaucoma patients. METHODS: This study is a retrospective, non-comparative, interventional case series. Ten eyes of nine pseudophakic malignant glaucoma patients with mean age of 63.3 years were analysed. All 10 eyes underwent a novel surgical technique, an anterior chamber capsulo-hyaloidectomy and anterior vitrectomy through the peripheral iridectomy. Main outcome measures were: reformation of the anterior chamber, intraocular pressure (IOP), best-corrected visual acuity (BCVA), and complications. RESULTS: All 10 eyes with pseudophakic malignant glaucoma were treated successfully by using a new surgical technique. All cases had a relief of aqueous misdirection with anterior chamber deepening during and after the surgery and post-operative intraocular pressure (IOP) normalization. No relapses have been observed so far. There were no complications during surgery and in the post-operative period. CONCLUSION: The presented surgical technique seems to be safe and effective in all cases of malignant glaucoma in pseudophakia.

Metal-organic frameworks: structural, energetic, electronic, and mechanical properties.

The structural, energetic, electronic, and mechanical properties of a series of metal-organic framework (MOF) materials have been systematically studied with the density functional based tight-binding method. The cubic array of Zn(4)O(CO2)6 units (connectors) connected by different types of organic secondary building blocks (linkers) was considered. The results show that these materials are stable with bulk moduli ranging from 0.5 to 24 GPa with decreasing size of the linker. All MOFs are semiconductors or insulators with band gaps between 1.0 and 5.5 eV, mainly determined by highest occupied molecular orbital-lowest unoccupied molecular orbital gaps of the linker molecules. The atomic charges are nearly the same for free building blocks and the solid MOFs.

[Histochemical studies of the myometrium in the prolonged pregnancy]. / Histochemische Untersuchungen des Myometriums in der übertragenen Schwangerschaft

There are several reports on the weak contractile activity of uterus in the prolonged pregnancy. Some investigations showed that the weak contractile activity is associated with the low contents of RNA, proteins and glycogen in the myometrial cell. The material was obtained from caesarean sections in 27 patients with prolonged pregnancy and 30 patients with normal pregnancy. It was found a diminished contents of glycogen and lipids in the myometrial cell, and a decreased activity of phosphorylase and alkaline phosphatase but an increased activity of acid phosphatase. The lower content of energetic material and changes in the activity of the enzymes shows that the metabolism of the myometrial cell is impaired in prolonged pregnancy. One can suppose that the lowered level of estrogens is responsible for the described changes. The lower level of estrogens probably causes the decrease of 3'5' AMP in the myometrial cell with the impaired cell metabolism as a consequence. This may be one of the causes of a weak uterine contractile activity in the prolonged pregnancy.