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consequently low carrier density limit its performance in electronic devices. [10] The carrier mobility of monolayer MoS 2 is relatively low and can even be seriously vulnerable against the optical phonons, defect and impurities. [11][12][13] Multilayer MoS 2 exposes much higher current density (400-1500 µA µm −1 ) and mobility (200-500 cm 2 V −1 s −1 ) than monolayer MoS 2 (current density: 50-700 µA µm −1 ; mobility: 70-100 cm 2 V −1 s −1 ), [14][15][16][17] making them more suitable for electronic application such as field effect transistors (FETs) and 2D device integrated circuits. Quantum transport simulations suggested that the bilayer and trilayer MoS 2 -based FETs could show better performance than the monolayer MoS 2 . [18][19][20] Excitingly, the bilayer MoS 2 based devices have been successfully demonstrated with very promising performance in experimental works. [21,22] Liu et al. produced bilayer MoS 2 films by the Scotch-tape technique and fabricated FETs devices with high on/ off ratio of 1 × 10 8 and field effect mobility of 517 cm 2 V −1 s −1 . [23] In addition, it was shown that the layerdependent electronic structures of multilayer MoS 2 can give rise to the unique optoelectronic response in devices. [24] However, the growth of large-area uniform multilayer MoS 2 , as the prerequisite of industrial application, is still very challenging. [25] Actually, the grand breakthrough was not made until very recently in the wafer-scale growth of monolayer MoS 2 single crystal films, in comparison with which the growth of large-area uniform multilayer MoS 2 is severely lagged. [26] Presently, the growth of multilayer MoS 2 films has commonly been achieved through the layer-by-layer growth mode via chemical vapor deposition (CVD) methods. [16,27,28] However, the multilayer MoS 2 films prepared by this route show poor uniformity on the thickness and domain size. This is attributed to that the nucleation of top-layer has to be occurred on the surface of previously grown bottom MoS 2 films, making it difficult to control the thickness and domain size of grown MoS 2 domain. Besides, the layer-by-layer growth mode would suffer from the synthesis time penalty and insufficient growth time will lead to a much smaller area of the upper MoS 2 layer than that of the lower layer and consequently a much smaller usable area of the grown film. [13] Hong et al. claimed that the growth of wafer-scale MoS 2 polycrystalline films within five layers could Multilayer MoS 2 shows superior performance over the monolayer MoS 2 for electronic devices while the growth of multilayer MoS 2 with controllable and uniform thickness is still very challenging. It is revealed by calculations that monolayer MoS 2 domains are thermodynamically much more favorable than multilayer ones on epitaxial substrates due to the competition between surface interactions and edge formation, leading accordingly to a layer-bylayer growth pattern and non-continuously distributed multilayer domains with uncontrollable thickness uniformity. The thermodynamics ...

Research question: Endometrial preparation is one of the most important steps for ensuring frozen embryo transfer success. However, there is no clear evidence that identifies an optimal endometrial preparation protocol for frozen embryo transfer. In addition, in studies that assessed which were the optimal endometrial preparation protocols, few analyzed the stage and the number of embryos. This study compared the pregnancy outcomes and perinatal obstetric complications of patients who were transferred two cleavage-stage (day 2 or day 3) frozen embryos with the natural cycle and those with the hormone replacement therapy cycle. Design: This study was a secondary analysis of data from a multicentre randomized controlled trial designed to compare the pregnancy and perinatal outcomes after frozen versus fresh embryo transfer. In this study, a total of 908 patients who were transferred two cleavage-stage (day 2 or day 3) embryos in the original trial were analyzed. Pregnancy outcomes and perinatal obstetric complications after the natural cycle and the hormone replacement therapy cycle were compared. Result: We found the endometrium in the natural group was significantly thicker than the hormone replacement therapy cycle group (p<0.01). The implantation rate (42.6% vs 37.3% p=0.049) showed a significant difference between the natural cycle group and the hormone replacement therapy cycle group. Compared to the natural cycle group, the hormone replacement therapy cycle group was associated with an increased risk of caesarean section (72.3% vs 84.5, p=0.009). Conclusion: The natural cycle protocol yielded thicker endometria, a higher implantation rate and a lower risk of caesarean section than the hormone replacement therapy protocol

The structures and properties of one-dimensional (1D) sandwich molecular wires constructed with altering 3d transition metal (TM) and the metallofullerene (TM@C 60 ) entities, [TM&(TM@C 60 )] ∞ , are studied using density functional theory calculations. Different from the bonding character insensitivity to TM of previously reported 1D [TMBz] ∞ and [TMCp] ∞ analogues, the bonding characters of the investigated 1D [TM&(TM@C 60 )] ∞ molecular wires depend heavily on the identity of metal elements. In 1D [TM&(TM@C 60 )] ∞ , molecular wires with early TMs like Ti and V, TM-η 5 coordinate bonds are favored. In contrast, TM-η 6 bonding conformations are energetically preferred for those with later TMs, for example, Cr−Ni. Bader charge analysis reveals that valence electrons are transferred from both encapsulated and sandwiched TM atoms to the C 60 ligand. More importantly, all the molecular wires in ground states are robust antiferromagnetic semiconductors because of the peierls distortion of the configurations and the moderate binding energies. Therefore, the fabrication of endohedral metallofullerenes offers an effective route to regulate the magnetism and electronic properties of C 60 −ligand sandwich complexes.

Two-dimensional (2D) boron-doped graphene (B-G) exhibits remarkable properties for advanced applications in electronics, sensing and catalysis. However, the synthesis of large-area uniformly ordered 2D B-G remains a grand challenge due...