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PtSe 2 and CuSe monolayers obtained by selenization of a metal substrate are shown to intrinsically form periodic patterns by varying the amount of Se atoms deposited. These patterns are used for the localized absorption of molecules and nanoclusters. Two-dimensional (2D) materials have been studied extensively as monolayers 1 , 2 , 3 , 4 , 5 , vertical or lateral heterostructures 6 , 7 , 8 . To achieve functionalization, monolayers are often patterned using soft lithography and selectively decorated with molecules 9 , 10 . Here we demonstrate the growth of a family of 2D materials that are intrinsically patterned. We demonstrate that a monolayer of PtSe 2 can be grown on a Pt substrate in the form of a triangular pattern of alternating 1T and 1H phases. Moreover, we show that, in a monolayer of CuSe grown on a Cu substrate, strain relaxation leads to periodic patterns of triangular nanopores with uniform size. Adsorption of different species at preferred pattern sites is also achieved, demonstrating that these materials can serve as templates for selective self-assembly of molecules or nanoclusters, as well as for the functionalization of the same substrate with two different species.

Summary Computer‐aided sperm analysis (CASA) system has been accepted and used commonly as a routine semen analysis instrument in hospital clinical laboratories worldwide. However, technicians in clinical laboratories have little informed knowledge about the principles of CASA system and the sources of analysis errors. In this review, we focus on the concept of CASA, the development course of CASA technology, the clinical application of CASA systems and the factors influencing the accuracies of results, such as frame rate, sperm counting chambers affiliated to the CASA system, algorithms and sperm concentration. These factors and lack of internal quality control may result in huge errors of the CASA between systems and laboratories. It is therefore necessary to perform the standardisation and quality control for CASA.

Summary There were controversial results between obesity‐associated markers and semen quality. In this study, we investigated the correlations between age, obesity‐associated markers including body mass index (BMI), waist‐to‐hip ratio (WHR), waist‐to‐height ratio (WHtR) and waist circumference (WC), the combination of age and obesity‐associated markers, semen parameters and serum reproductive hormone levels in 1231 subfertile men. The results showed that BMI, WC, WHR and WHtR were positively related to age, and there were also positive relations between BMI, WHR, WC and WHtR and between sperm concentration (SC), total sperm count (TSC), progressive motility (PR), sperm motility and per cent of normal sperm morphology (NSM). However, age, each of obesity‐associated markers and the combination of obesity‐associated markers and age were unrelated to any of semen parameters including total normal‐progressively motile sperm count (TNPMS). Age, BMI, WHR, WC and WHtR were negatively related to serum testosterone and SHBG levels. However, only serum LH and FSH levels were negatively related to sperm concentration, NSM and sperm motility. In a conclusion, although age and obesity have significant impacts on reproductive hormones such as testosterone, SHBG and oestradiol, semen parameters related to FSH and LH could not be influenced, indicating that obesity‐associated markers could not predict male semen quality.

When a crystal is subjected to a periodic potential, under certain circumstances it can adjust itself to follow the periodicity of the potential, resulting in a commensurate state. Of particular interest are topological defects between the two commensurate phases, such as solitons and domain walls. Here we report a commensurate–incommensurate transition for graphene on top of hexagonal boron nitride (hBN). Depending on the rotation angle between the lattices of the two crystals, graphene can either stretch to adapt to a slightly different hBN periodicity (for small angles, resulting in a commensurate state) or exhibit little adjustment (the incommensurate state). In the commensurate state, areas with matching lattice constants are separated by domain walls that accumulate the generated strain. Such soliton-like objects are not only of significant fundamental interest, but their presence could also explain recent experiments where electronic and optical properties of graphene-hBN heterostructures were observed to be considerably altered. A single layer of graphene on top of a hexagonal boron-nitride sheet can stretch to form a commensurate structure, or not — depending on the rotation angle between the two layers. In the case of commensurability, strain gets concentrated in domain walls, resulting in soliton-like structures.

The present protocol was aimed at establishing a routine transformation procedure via Agrobacterium tumefaciens for an important Oncidium orchid cultivar. An expression vector containing hptII and gusA genes driven by the cauliflower mosaic virus (CaMV) 35S promoter was successfully introduced into the Oncidium orchid genome by A. tumefaciens. Protocorm-like bodies (PLBs) derived from protocorms, were the target explants for transformation. The transformation was performed through two stages of cocultivation, the first stage occurring on antibiotic-free medium for 3 days, and the subsequent stage on medium containing 100 mg/l timentin for 1 month. Among 1,000 inoculated PLBs, 108 putatively transformed PLBs were proliferated on 5 mg/l hygromycin selection medium. A total of 28 independent transgenic orchid plants were obtained, from which six transgenic lines that were positive for beta-glucuronidase were randomly selected and confirmed by Southern, northern and western blot analyses. These results indicated that the foreign DNA was successfully integrated into the orchid genome and expressed transcriptionally and translationally in these orchid plants. The present transformation method reported is suitable for improving the Oncidium orchid through genetic engineering.

We report a case of giant gastrointestinal stromal tumour of the stomach in a 71-year-old woman, with emphasis on its going through surgical resection. The physical examination and radiological findings revealed that a giant mass occupied most of the abdominal cavity. The patient underwent an en-block resection of the mass, partial resection of the distal stomach and Billroth II gastrojejunostomy. The pathological diagnosis was gastrointestinal stromal tumour. The patient had a long-term disease-free survival. We emphasise that complete surgical resection is the only effective radical treatment approach for giant gastrointestinal stroma of the stomach. In some cases, we still have the opportunity for resection of these tumours because of their expansive growth, even though the lesions are very large.

This paper investigates a multistage production-inventory model for deteriorating items, including raw materials and finished goods, based on collaborative preservation technology investment. The major purpose is to determine the optimal materials supply, production delivery, replenishment, and investment policies for the retailer and manufacturer in which the joint total profit of the integrated system is maximized. Mathematical programming analysis is employed to ascertain the optimal solutions for the retailer and manufacturer. Furthermore, several numerical examples are presented to demonstrate solution process and verify the concavity of the proposed model. Sensitivity analyses with respect to major parameters are also performed. The numerical results show that market demand, fixed shipping cost, production rate, manufacturer's sales price, and holding cost of finished good may affect the optimal number of shipments. In addition, when collaborative preservation technology investment becomes an option, the effect of the deterioration rate on the shipping and ordering quantity will be reduced through investment in improving deterioration of raw material or finished good. Finally, the increase in the amount of raw materials used to produce a finished product implies that the amount of finished goods produced by the original material is reduced; therefore, the collaborative preservation technology investment is increased.

Shelf management is a crucial task in retailing. Because of the large number of products found in most retail stores (sometimes more than 60 000), current shelf space management models can only solve sub-problems of the overall store optimization problem, since the size of the complete optimization problem would be prohibitively large. Consequently, an optimal allocation of store shelf space to products has not yet been achieved. We show that a hierarchical decomposition technique, consisting of two interwoven models, is suitable to overcome this limitation and, thus, is capable of finding accurate solutions to very large and complex shelf space management problems. We further conclude that other important variables (such as product-price) can be included into the methodology and their optimal values can be determined using the same solution technique. Our methodology is illustrated on a real-life application where we predict a 22.33% increase in store profits if our model's solution is implemented.

Aim: This study explores anaerobic/aerobic biodegradation efficiencies of aerobic cometabolism with methanotrophs when contaminants trichloroethylene (TCE) and cis-1,2-dichloroethylene (cDCE) are present individually or in tandem. Methodology: Batch tests and an anaerobic/aerobic column system were used to simulate saturated, contaminated aquifers. A brown glass bottle with an effective volume of 44 m l-1 was prepared for the batch test. An integrated one-dimensional sequential anaerobic/aerobic column system was used to simulate the accumulative intermediates such as TCE, cDCE and VC caused by incomplete degradation of PCE during the upgradient anaerobic stage in the saturated aquifer. In the downgradient aquifer, aerobic cometabolism was employed to degrade the intermediates. Methanotrophs in the aerobic aquifer were inoculated to degrade the by-products of incomplete degradation of PCE by aerobic cometabolism. Results: In the batch test, biodegradation of TCE was significantly inhibited by cDCE. However, biodegradation of cDCE was not significantly inhibited by TCE. In the simulated aquifer test, aerobic cometabolism completely degraded intermediates (TCE, cDCE, and VC) produced by incomplete anaerobic degradation of tetrachloroethylene (PCE). The results showed that methane, a by-product of anaerobic reductive dechorination of PCE, was used as a primary substrate for aerobic degradation, at a utilization rate of almost 100%. Interpretation: Biodegradation of TCE was significantly inhibited by cDCE. Bioremediation should have sufficient oxygen and methane at aerobic stage to ensure that chlorinated ethenes fully mineralize.

An approach is presented for solving plate bending problems using a high-order infinite element method (IEM) based on Mindlin–Reissner plate theory. In the proposed approach, the computational domain is partitioned into multiple layers of geometrically similar virtual elements which use only the data of the boundary nodes. Based on the similarity, a reduction process is developed to eliminate virtual elements and overcome the problem that the conventional reduction process cannot be directly applied. Several examples of plate bending problems with complicated geometries are reported to illustrate the applicability of the proposed approach and the results are compared with those obtained using ABAQUS software. Finally, the bending behavior of a rectangular plate with a central crack is analyzed to demonstrate that the stress intensity factor (SIF) obtained using the high-order PIEM converges faster and closer than low-order PIEM to the analytical solution.