Engineering electronic properties is a promising way to design nonprecious-metal or earth-abundant catalysts toward hydrogen evolution reaction (HER). Herein, we deposited catalytically active MoS flakes onto black phosphorus (BP) nanosheets to construct the MoS-BP interfaces. In this case, electrons flew from BP to MoS in MoS-BP nanosheets because of the higher Fermi level of BP than that of MoS. MoS-BP nanosheets exhibited remarkable HER performance with an overpotential of 85 mV at 10 mA cm. Due to the electron donation from BP to MoS, the exchange current density of MoS-BP reached 0.66 mA cm, which was 22 times higher than that of MoS. In addition, both the consecutive cyclic voltammetry and potentiostatic tests revealed the outstanding electrocatalytic stability of MoS-BP nanosheets. Our finding not only provides a superior HER catalyst, but also presents a straightforward strategy to design hybrid electrocatalysts.

The maximum bond order between two main-group atoms was known to be three. However, it has been suggested recently that there is quadruple bonding in C 2 and analogous eight-valence electron species. While the quadruple bond in C 2 has aroused some debates, an interesting question is: are main-group elements capable of forming quadruple bonds? Here we use photoelectron spectroscopy and computational chemistry to probe the electronic structure and chemical bonding in RhB 2 O − and RhB − and show that the boron atom engages in quadruple bonding with rhodium in RhB(BO) − and neutral RhB. The quadruple bonds consist of two πbonds formed between the Rh 4d xz /4d yz and B 2p x /2p y orbitals and two σ-bonds between the Rh 4d z 2 and B 2s/2p z orbitals. To confirm the quadruple bond in RhB, we also investigate the linear RhB−H + species and find a triple bond between Rh and B, which has a longer bond length, lower stretching frequency, and smaller bond dissociation energy in comparison with that of the Rh≣B quadruple bond in RhB.

Introduction: To evaluate the accuracy of deep convolutional neural networks (DCNNs) for detecting neck of femur (NoF) fractures on radiographs, in comparison with perceptual training in medically-na€ ıve individuals. Methods: This study extends a previous study that conducted perceptual training in medically-na€ ıve individuals for the detection of NoF fractures on a variety of dataset sizes. The same anteroposterior hip radiograph dataset was used to train two DCNNs (AlexNet and GoogLeNet) to detect NoF fractures. For direct comparison with perceptual training results, deep learning was completed across a variety of dataset sizes (200, 320 and 640 images) with images split into training (80%) and validation (20%). An additional 160 images were used as the final test set. Multiple pre-processing and augmentation techniques were utilised. Results: AlexNet and GoogLeNet DCNNs NoF fracture detection accuracy increased with larger training dataset sizes and mildly with augmentation. Accuracy increased from 81.9% and 88.1% to 89.4% and 94.4% for AlexNet and GoogLeNet respectively. Similarly, the test accuracy for the perceptual training in top-performing medically-na€ ıve individuals increased from 87.6% to 90.5% when trained on 640 images compared with 200 images. Conclusions: Single detection tasks in radiology are commonly used in DCNN research with their results often used to make broader claims about machine learning being able to perform as well as subspecialty radiologists. This study suggests that as impressive as recognising fractures is for a DCNN, similar learning can be achieved by top-performing medically-na€ ıve humans with less than 1 hour of perceptual training.

The discovery of borospherenes unveiled the capacity of boron to form fullerene-like cage structures. While fullerenes are known to entrap metal atoms to form endohedral metallofullerenes, few metal atoms have been observed to be part of the fullerene cages. Here we report the observation of a class of remarkable metallo-borospherenes, where metal atoms are integral parts of the cage surface. We have produced La 3 B 18and Tb 3 B 18and probed their structures and bonding using photoelectron spectroscopy and theoretical calculations. Global minimum searches revealed that the most stable structures of Ln 3 B 18are hollow cages with D 3h symmetry. The B 18-framework in the Ln 3 B 18cages can be viewed as consisting of two triangular B 6 motifs connected by three B 2 units, forming three shared B 10 rings which are coordinated to the three Ln atoms on the cage surface. These metalloborospherenes represent a new class of unusual geometry that has not been observed in chemistry heretofore.

Size-selected negatively-charged boron clusters (Bn−) have been found to be planar or quasi-planar in a wide size range. Even though cage structures emerged as the global minimum at B39−, the...

Diagnosing certain fractures in conventional radiographs can be a difficult task, usually taking years to master. Typically, students are trained ad-hoc, in a primarily-rule based fashion. Our study investigated whether students can more rapidly learn to diagnose proximal neck of femur fractures via perceptual training, without having to learn an explicit set of rules. One hundred and thirty-nine students with no prior medical or radiology training were shown a sequence of plain film X-ray images of the right hip and for each image were asked to indicate whether a fracture was present. Students were told if they were correct and the location of any fracture, if present. No other feedback was given. The more able students achieved the same level of accuracy as board certified radiologists at identifying hip fractures in less than an hour of training. Surprisingly, perceptual learning was reduced when the training set was constructed to over-represent the types of images participants found more difficult to categorise. Conversely, repeating training images did not reduce post-training performance relative to showing an equivalent number of unique images. Perceptual training is an effective way of helping novices learn to identify hip fractures in X-ray images and should supplement the current education programme for students.

Fibroblast growth factor-2 (FGF-2) has been found to have stimulatory effects on fracture repair at diaphysis, while its effect on metaphyseal fracture repair, where spongiosal bone is dominant, has not been studied. This study was conducted to investigate the effect of FGF-2 on metaphyseal fracture healing in a rabbit proximal tibial metaphyseal model. The proximal tibial metaphysis of 6-month-old Japanese white rabbits was osteotomized bilaterally. Then 400 microg of FGF-2, mixed with gelatin hydrogel, and gelatin hydrogel alone (the control) were injected to each osteotomy site of the rabbit proximal tibiae, and the osteotomies were fixed with staples. One and 2 weeks after surgery, the osteoid area in the repairing spongiosal bone at the fracture site was significantly larger in the FGF-2 group than in the control group ( P < 0.05). On immunohistochemistry, proliferating-cell nuclear antigen-positive cells had a tendency to show greater numbers in the FGF-2 group. After 4 and 8 weeks, values for bone mineral density and the cancellous bone area in the healing region of the fracture site were significantly larger in the FGF-2 group ( P < 0.05). These data suggest that local application of FGF-2 may have an accelerating effect on the repair of metaphyseal fractures. Exogenous recombinant human rhFGF-2 may have potential clinical applications in metaphyseal fracture treatment.

The relationship between the global minima of a tilted inverse triple-decker La3B14− and a perfect inverse triple decker La⋯B8⋯La⋯B8⋯La.