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Summary The scalable preparation of high-purity monolayers is essential for practically integrating two-dimensional (2D) semiconductors in diverse technologies but remains a persistent challenge. Previous efforts to exfoliate 2D layered crystals by the organic ammonium intercalation usually produce few-layer nanosheets owing to a self-retarding effect that hinders the complete intercalation in neighboring layers. Herein, we report a unique “intercalation and separation” chemistry with a constant self-refreshing crystal surface that mitigates the self-retarding effect to ensure a complete intercalation of the bulk crystal, ultimately enabling high-yield solution-phase exfoliation of 2D semiconductor monolayers in excellent purity (e.g., monolayer purity of >95% for In2Se3 and InSe). Furthermore, we have assembled large-area organic/inorganic hybrid superlattices with diverse organic molecules and inorganic 2D monolayer crystals, thus creating a family of artificial superlattice materials with atomically modulated chemical compositions, widely tunable superlattice periodicities, and specifically tailorable electronic and thermal properties.

The discovery of intrinsic ferromagnetism in ultrathin two-dimensional van der Waals crystals opens up exciting prospects for exploring magnetism in the ultimate two-dimensional limit. Here, we show that environmentally stable CrSe2 nanosheets can be readily grown on a dangling-bond-free WSe2 substrate with systematically tunable thickness down to the monolayer limit. These CrSe2/WSe2 heterostructures display high-quality van der Waals interfaces with well-resolved moire superlattices and ferromagnetic behaviour. We find no apparent change in surface roughness or magnetic properties after months of exposure in air. Our calculations suggest that charge transfer from the WSe2 substrate and interlayer coupling within CrSe2 play a critical role in the magnetic order in few-layer CrSe2 nanosheets. The highly controllable growth of environmentally stable CrSe2 nanosheets with tunable thickness defines a robust two-dimensional magnet for fundamental studies and potential applications in magnetoelectronic and spintronic devices.

The complete mitogenome sequence of the lesser bandicoot rat (Bandicota bengalensis Gray and Hardwicke, 1833) was determined using long PCR. The genome was 16,327 bp in length and contained 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, 1 origin of L strand replication and 1 control region. The overall base composition of the heavy strand is A (34.2%), C (24.9%), T (28.5%) and G (12.4%). The base compositions present clearly the A–T skew, which is most obviously in the control region and protein-coding genes. Mitochondrial genome analyses based on MP, ML, NJ and Bayesian analyses yielded identical phylogenetic trees. This study verifies the evolutionary status of Bandicota bengalensis in Muridae at the molecular level. The mitochondrial genome would be a significant supplement for the Bandicota bengalensis genetic background. The two Bandicota species formed a monophyletic group with the high bootstrap value (100%) in all examinations.

Lead halide perovskites have attracted increasing interest for their exciting potential in diverse optoelectronic devices. However, their charge transport properties remain elusive, plagued by the issues of excessive contact resistance and large hysteresis in ambient conditions. Here we report a van der Waals integration approach for creating high-performance contacts on monocrystalline halide perovskite thin films with minimum interfacial damage and an atomically clean interface. Compared to the deposited contacts, our van der Waals contacts exhibit two to three orders of magnitude lower contact resistance, enabling systematic transport studies in a wide temperature range. We report a Hall mobility exceeding 2,000 cm2 V–1 s–1 at around 80 K, an ultralow bimolecular recombination coefficient of 3.5 × 10–15 cm3 s–1 and a photocurrent gain >106 in the perovskite thin films. Furthermore, magnetotransport studies reveal a quantum-interference-induced weak localization behaviour with a phase coherence length up to 49 nm at 3.5 K. Our results lay the foundation for exploring new physics in this class of ‘soft-lattice’ materials. The realization of high-quality van der Waals contacts on monocrystalline halide perovskite thin films enables the probing of their long-range carrier and photocarrier transport properties.

Purpose Cabazitaxel (CBZ) is a new taxane-based antitumor drug approved by the FDA for the treatment of prostate cancer, especially for patients with advanced prostate cancer for whom docetaxel is ineffective or causes aggravation. However, Tween 80 injection can cause serious allergic reactions, and CBZ itself has strong toxicity, adverse reactions, and poor tumor selectivity, which greatly limits its clinical applications. Therefore, the CBZ-loaded bovine serum albumin nanoparticles (CBZ-BSA-Gd-NPs) were developed to overcome the allergenic response of Tween 80 and realize the integration of diagnosis and treatment. Methods CBZ-BSA-Gd-NPs were prepared by the biomineralization method. The characterization, magnetic resonance imaging (MRI), safety, and antitumor activity of the nanoparticles were evaluated in vitro and in vivo. Results The prepared nanoparticles were uniform in size (166 nm), with good MRI performance and stability over 24 h. Compared with CBZ-Tween 80 injection, CBZ-BSA-Gd-NPs showed much lower hemolysis, similar tumor inhibition, and enhanced cellular uptake in vitro. The pharmacokinetic behavior of CBZ-BSA-Gd-NPs in rats showed that the retention time of the nanoparticles was prolonged, the clearance rate decreased, and the area under the drug-time curve increased. The distribution of CBZ-BSA-Gd-NPs in nude mice was characterized by UPLC-MS/MS and MRI, and the results showed that CBZ-BSA-Gd-NPs could effectively target tumor tissues with reduced distribution in the heart, liver, spleen, lungs, and kidneys compared with CBZ-Tween 80, which indicated that CBZ-BSA-Gd-NPs not only had a passive targeting effect on tumor tissue but also achieved the integration of diagnosis and treatment. In vivo, CBZ-BSA-Gd-NPs showed improved tumor inhibitory effect with a safer profile. Conclusion In summary, CBZ-BSA-Gd-NPs can serve as an effective therapeutic drug carrier to deliver CBZ into prostate cancer, and realize the integration of diagnosis and therapy.

Polyploidy can cause variation in plant functional traits and thereby generate individuals that can adapt to fluctuating environments and exploit new environments. However, few empirical studies have tested for an association between ploidy level and climatic tolerance of invasive cytotypes relative to conspecific native‐range cytotypes. Here, we used an invasive plant Solidago canadensis to test whether invasive populations had a higher proportion of polyploids, greater height and stem‐base diameter, and occupied a wider range of climatic conditions than conspecific native‐range populations. We also tested whether the invasive populations had overcome genetic founder effects. We sampled a total of 80 populations in parts of the invaded range in China and native range in North America for in situ measurements of plant height and stem‐base diameter in the field and for population genetic and cytotype analyses. To examine climatic correlates, we augmented our field‐sampled data with occurrence records obtained from Global Biodiversity Information Facility. All, except one, of the populations that we sampled in China occurred in a humid subtropical climate. In contrast, the North American populations occurred in humid continental, humid subtropical, and semi‐arid climatic zones. All populations of S. canadensis in China were purely hexaploid, while the North American populations were diploid, tetraploid, and hexaploid. The invasive hexaploids were significantly taller and had a larger stem‐base diameter than native hexaploids. Native hexaploids were significantly taller and had larger stem‐base diameter than native diploids. Climatic correlate assessment found that invasive and native populations occupied different climatic envelopes, with invasive populations occurring in warmer and less seasonal climates than native populations. However, there was no significant correlation between ploidy level and climatic envelope of S. canadensis. Molecular phylogeography data suggest reduced genetic founder effects in the invaded range. Overall, these results suggest that polyploidy does not influence S. canadensis climatic tolerance.

Online retailers are increasingly adding buy-online and pick-up-in-store (BOPS) modes to order fulfilment. In this paper, we study a system of BOPS by developing a stochastic Nash equilibrium model with incentive compatibility constraints, where the online retailer seeks optimal online sale prices and an optimal delivery schedule in an order cycle, and the offline retailer pursues a maximal rate of sharing the profit owing to the consignment from the online retailer. By an expectation method and optimality conditions, the equilibrium model is first transformed into a system of constrained nonlinear equations. Then, by a case study and sensitivity analysis, the model is validated and the following practical insights are revealed. (I) Our method can reliably provide an equilibrium strategy for the online and offline retailers under BOPS mode, including the optimal online selling price, the optimal delivery schedule, the optimal inventory and the optimal allocation of profits. (II) Different model parameters, such as operational cost, price sensitivity coefficient, cross-sale factor, opportunity loss ratio and loss ratio of unsold goods, generate distinct impacts on the equilibrium solution and the profits of the BOPS system. (III) Optimization of the delivery schedule can generate greater consumer surplus, and makes the offline retailer share less sale profit from the online retailer, even if the total profit of the BOPS system becomes higher. (IV) Inventory subsidy is an indispensable factor to improve the applicability of the game model in BOPS mode.

In this paper, a new spectral scaling memoryless Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm is developed for solving large scale unconstrained optimization problems, where the scaling parameter is chosen so as to minimize all the eigenvalues of search direction matrices. The search directions in this algorithm are proved to satisfy the approximate Dai-Liao conjugate condition. With this advantage of the search directions, a scaling memoryless BFGS update formula is constructed and an algorithm is developed by incorporating acceleration strategy of line search and restart criterion. Under mild assumptions, global convergence of the algorithm is proved. Numerical tests demonstrate that the developed algorithm is more robust and efficient in solving large scale benchmark test problems than the similar ones in the literature.

The complete mitogenome sequence of Ochotona hyperborea was determined using long PCR. The genome was 17,063 bp in length and contained 13 protein-coding genes, two ribosomal RNA genes, 22 transfer RNA genes, one origin of L strand replication, and one control region. The overall base composition of the heavy strand is A (31.1%), C (28.7%), T (26.3%), and G (13.9%). The base compositions present clearly the A–T skew, which is most obvious in the control region and protein-coding genes. Mitochondrial genome analyses based on MP, ML, NJ, and Bayesian analyses yielded identical phylogenetic trees. This study verifies the evolutionary status of Ochotona hyperborea in Ochotonidae at the molecular level. The mitochondrial genome would be a significant supplement for the Ochotona hyperborea genetic background. The eight Ochotona species formed a monophyletic group with the high bootstrap value (100%) in all examinations.

The expansion and intensification of agricultural lands (i.e., croplands and pasture areas) have become increasing threats to species diversity around the world. However, genus diversity should be considered for biodiversity conservation due to the important role that phylogenetic diversity and evolutionary history play shaping biodiversity patterns, particularly in the Neotropics, the most species-rich realm. Here, we explored agricultural land effects on distribution patterns of terrestrial vertebrate diversity at the genus level using cases from the Neotropics. We compiled distribution data on genera of amphibians, birds, mammals, and reptiles and explored the effects of agricultural lands on genus diversity distribution patterns for terrestrial vertebrates in the region using distribution modelling. Geography Weighting Regression (GWR) was used to explore the spatially variable relationship between agricultural lands and genus diversity. We found that there are significant, non-stationary relationships between agricultural lands and genus diversity in the Neotropics. The non-stationary relationship between croplands and genus diversity was stronger than that between pasture areas and genus diversity. Furthermore, these effects may depend on changes in genus groups (i.e., amphibians, birds, mammals, and reptiles) and biomes. The relationship was the strongest for the croplands and reptile diversity pair at the genus levels. The relationship between both croplands and pasture areas and reptile diversity was the largest in temperate broadleaf and mixed forests. Given the influence of crop and pasturelands on vertebrate distribution patterns, we argue that agriculture development should be considered in the spatial prioritization of conservation for vertebrates in the Neotropics. Agricultural lands should be used as environmental variables for distribution modelling, and understanding the impacts of agricultural lands on biodiversity is critical for effective conservation management in the Neotropics.

Domain walls in fractional quantum Hall ferromagnets are gapless helical one-dimensional channels formed at the boundaries of topologically distinct quantum Hall (QH) liquids. Na\"{i}vely, these helical domain walls (hDWs) constitute two counter-propagating chiral states with opposite spins. Coupled to an s-wave superconductor, helical channels are expected to lead to topological superconductivity with high order non-Abelian excitations. Here we investigate transport properties of hDWs in the $\nu=2/3$ fractional QH regime. Experimentally we found that current carried by hDWs is substantially smaller than the prediction of the na\"{i}ve model. Luttinger liquid theory of the system reveals redistribution of currents between quasiparticle charge, spin and neutral modes, and predicts the reduction of the hDW current. Inclusion of spin-non-conserving tunneling processes reconciles theory with experiment. The theory confirms emergence of spin modes required for the formation of fractional topological superconductivity., Comment: 26 pages, 8 figures

Background: Historical and contemporary climates may shape the distributional patterns of plant species richness across different scales. However, few studies have focused on the effects of historical and contemporary climate changes on the distributional patterns of plant richness in Chinese protected areas across different taxonomic levels. Hypotheses: Historical and contemporary climates can have an important legacy effect on the large-scale distributional patterns of plant richness across different taxonomic levels. Studied species: Vascular plants. Study site: China. Method: We used data on plant richness at the family, genus, and species levels from Chinese protected areas and applied regression modelling to explore the relationships between climate change and plant richness among vascular, fern, seed, gymnosperm, and angiosperm plants based on paleoclimate (Last Glacial Maximum; LGM, ca. 22,000 years ago) and contemporary climate data. Results: The large-scale distributional patterns of plant richness could be predicted across different taxonomic levels on the basis of paleoclimate and contemporary climate data. Specifically, historical and contemporary climate variables were found to better correlate with fern plant richness than seed plant richness. For seed plants, the explanatory power of historical and contemporary climate variables was found to be stronger for the richness of gymnosperms than for the richness of angiosperms. Conclusions: The distributional pattern of plant richness could be predicted across different taxonomic levels after including paleoclimate (LGM, ca. 22,000 years ago) and contemporary climate data from China. Our study could support the effectiveness of the management of protected areas in China.

MaxEnt, a commonly used approach of species distribution modelling, is widely used to predict plant invasion at the large spatial scale based on occurrence records and environmental variables. However, the number of occurrence records, number of environmental variables, and spatial scales have a large potential to affect the ability of MaxEnt to predict invasive plant distributions. In this study, we used the area under the curve (AUC) of the receiver operator characteristics as an indicator of MaxEnt performance, and evaluated the effects of the number of occurrence records, number of environmental variables, and spatial scales on MaxEnt distribution modelling of invasive plants based on 1015 cases of invasive plants. Next, we suggested improvements for model performance. We found significant relationships between the AUC and the above-mentioned modelling parameters. Furthermore, we determined the relevant threshold values for the available MaxEnt models (i.e. AUC >0.7). We suggested using an appropriate number of occurrence records and environmental variables (e.g. >5) and covered cell sizes of 5.0 arc-min to model the distributions of invasive plants on the global scale. Our study provides practical references using MaxEnt to prevent and control plant invasion under global changes and contributes to the exploration of species distribution modelling mechanisms.

Clonal plant species can produce genetically identical and potentially independent offspring, and dominate a variety of habitats. The divergent evolutionary mechanisms between clonal and non-clonal plants are interesting areas of ecological research. A number of studies have shown that the environmental niche theory can support the mechanisms of evolution across plant species clades at large scales. However, few studies have explored large-scale environmental niche variation between clonal and non-clonal plant species. Here, we used principal component analysis to quantify the environmental niche of 137 plant species belonging to 13 genera, including 87 clonal species and 50 non-clonal species. We then used a standardized effect size to assess environmental niche variation between clonal and non-clonal plant species within each genus, based on types of clonal growth organs and ecoregions. Our study provided the first evidence that there were significant environmental niche differences between clonal and non-clonal plant species at large scales. Such differences varied depending on the types of clonal growth organs and ecoregions. Clonal plants with different growth organs (i.e., epigeogenous stems, hypogeogenous stems, root-splitters, and adventitious buds on roots) contributed greatly to differences in climatic niches between clonal and non-clonal plants. Differences in environmental niches between clonal and non-clonal plant species also depended on ecoregion types. Specifically, the ecoregions of temperate broadleaf and mixed forests can lead to environmental niche variation between clonal and non-clonal plant species. Our results provide new insights into the evolutionary divergence between clonal and non-clonal plant species.

Two-dimensional (2D) metallic transition metal dichalcogenides (MTMDs) have recently drawn increasing interest for fundamental studies and potential applications in catalysis, charge density wave (...

We propose a new adaptive and composite Barzilai–Borwein (BB) step size by integrating the advantages of such existing step sizes. Particularly, the proposed step size is an optimal weighted mean of two classical BB step sizes and the weights are updated at each iteration in accordance with the quality of the classical BB step sizes. Combined with the steepest descent direction, the adaptive and composite BB step size is incorporated into the development of an algorithm such that it is efficient to solve large-scale optimization problems. We prove that the developed algorithm is globally convergent and it R-linearly converges when applied to solve strictly convex quadratic minimization problems. Compared with the state-of-the-art algorithms available in the literature, the proposed step size is more efficient in solving ill-posed or large-scale benchmark test problems. doi:10.1017/S1446181118000263

Breast cancer is one of the leading causes of cancer-related deaths in women. Chemotherapy remains one of the main clinical treatments for breast cancer. However, this therapy has appreciable side effects. Nanoscale carriers, such as metal nanoparticles and liposomes, are being widely utilized as drug delivery vehicles to achieve precise targeting of tumor cells. In this study, we designed a novel upconversion nanocarriers (UCNCs) host-guest complexation system based on a photolabile capping-like molecule. UCNCs containing epirubicin (EPI) were grafted with a dimer-targeting peptide via cyclodextrin-adamantine host-guest complexation. After entering breast tumor cells with the guidance of the dimer-targeting peptide, the core of the UCNCs upconverted near-infrared light to ultraviolet light which subsequently triggered the intracellular on-demand release of epirubicin. The precise and efficient delivery and release of epirubicin inside breast cancer cells significantly inhibited cancer cells proliferation, migration, and invasion in vitro and decreased the tumor size in vivo. We believe that this UCNCs system is a promising platform for the precise and controllable delivery of various chemotherapy drugs for clinical cancer treatments.

Nonnegative Matrix Factorization (NMF) has received great attention in the era of big data, owing to its roles in efficiently reducing data dimension and producing feature-based data representation. In this paper, we first propose two new NMF optimization models, called an orthogonal dual graph regularized nonnegative matrix factorization (ODGNMF) method and its modified version: an orthogonal dual graph regularized nonnegative matrix tri-factorization (ODGNMTF) method. Compared with the existing models, our models can preserve the geometrical structures of data manifold and feature manifold by constructing two graphs, and ensure the orthogonality of factor matrices such that they have better NMF performance. Then, two efficient algorithms are developed to solve the models, and the convergence theory of the algorithms is established. Numerical tests by applying our algorithms to mine randomly generated data sets and well-known public databases demonstrate that ODGNMF and ODGNMTF have better numerical performance than the state-of-the-art algorithms in view of computational cost, robustness, sensitivity and sparseness.

The large-scale relationship between gross primary productivity (GPP) and plant species richness (PSR) remains a fundamental topic in macro-ecology. Although there have been numerous studies of the connection between GPP and PSR, this relationship (linear or unimodal) is still debatable at geographical scales. Using geographically weighted regression and ordinary least squares, GPP and PSR data from protected areas in China were used to explore the complex relationship between GPP and PSR across different taxonomic groups (i.e. vascular plants, ferns, seed plants, gymnosperms, and angiosperms). Results showed that GPP was significantly related to PSR for all taxonomic groups at geographical scales (p

Background Growth in insect pest populations poses a significant threat to ecosystem functions and services, societal development, and food security in alpine regions under climate change. Risk assessments are important prioritization tools for pest management, which must be used to study insect pest expansion in alpine ecosystems under global warming. We used species distribution modeling to simulate the current and future distribution probabilities of 58 insect pest species in the Qinghai Province, China, based on a comprehensive field investigation. Subsequently, general linear modeling was used to explore the relationship between the distribution probability of these species and the damage caused by them. Finally, we assessed the ecological risk of insect pest expansion across different alpine ecosystems under climate change. Results Climate change could increase the distribution probabilities of insect pest species across different alpine ecosystems. However, the presence of insect pest species may not correspond to the damage occurrence in alpine ecosystems based on percent leaf loss, amount of stunting, and seedling death of their host species. Significant positive relationships between distribution probability and damage occurrence were found for several of the examined insect pest species. Insect pest expansion is likely to increase extensively in alpine ecosystems under increasing carbon dioxide (CO2 ) emission scenarios. Conclusion The relationships between distribution probability and damage occurrence should be considered in species distribution modeling for risk assessment of insect pest expansion under climate change. Our study could improve the effectiveness of risk assessment of insect pest expansion under changing climate conditions. © 2021 Society of Chemical Industry.

Weed expansion has the potential to severely affect global agriculture. Habitat suitability models (HSMs) have been widely used to assess weed expansion to enable effective prevention and control of weeds. However, few studies have focused on the habitat suitability of global croplands for these weeds. Previous studies listed the 10 serious weed species that have the largest negative impact on global agriculture. Here, we used Maxent modeling (an HSM with good performance) to quantify the habitat suitability of global croplands for these 10 weed species using occurrence records and environmental variables (i.e., climate factors, soil properties, and human footprint). We compared the habitat suitability values of these 10 serious weed species in 174 different types of cropland. The habitat suitability values for all the weed species studied was high in global croplands. Furthermore, habitat suitability may depend on the type of cropland and the spatial variation created by varying climate factors, soil properties, and human footprint. Cynodon dactylon, Echinochloa crus-galli, Eleusine indica, Panicum maximum, and Sorghum halepense had the highest habitat suitability values in chicory plantations. Cyperus rotundus and Echinochloa colona had the highest habitat suitability values in olive plantations. The habitat suitability values for Imperata cylindrica was the highest in mustard plantations, Eichhornia crassipes was most suited to expansion in raspberry plantations, and the habitat suitability values for Lantana camara was the highest in chickpea plantations. Risk prevention and control should be based on the cropland type for these 10 serious weed species, taking into account climate factors, soil properties, and human activities. Our study provides guidelines for effective management of weed risk in different croplands globally.

Vascular plant richness contributes significantly to ecosystem function and services. Understanding the environmental predictors of vascular plant richness can therefore support conservation efforts of biodiversity and ecosystem services at large spatial scales. This study used protected area data to explore the environmental predictors of vascular plant richness at different taxonomic levels (i.e., family, genus, and species), to improve the integrity and function of protected areas. Climate variables (i.e., annual mean temperature, minimum temperature of the coldest month, and annual precipitation) and soil parameters (i.e., soil texture, soil pH, bulk density, organic carbon stock, and coarse-fragment volume) were found to largely predict vascular plant richness across different taxonomic levels. Moreover, these were the most effective at the family level. The following measures are therefore proposed to improve conservation management of protected areas. 1) The effects of climate change on vascular plant richness should be accounted for during the spatial planning of protected areas. 2) The interaction between vascular plant richness and soil variables should be considered for the management of protected areas. 3) Human activities should be controlled to establish a balance between strict protection and the sustainable use of natural resources in the protected area network. However, the effect of human activities alone could not explain the variance of vascular plant richness at large spatial scales. This study provides effective guidelines for the sustainable management of plant diversity in protected areas at large spatial scales. Keywords: Climatic factors, Conservation management, Human footprint, Plant diversity, Protected area, Soil properties

Two-dimensional (2D) materials1,2 and the associated van der Waals (vdW) heterostructures3-7 have provided great flexibility for integrating distinct atomic layers beyond the traditional limits of lattice-matching requirements, through layer-by-layer mechanical restacking or sequential synthesis. However, the 2D vdW heterostructures explored so far have been usually limited to relatively simple heterostructures with a small number of blocks8-18. The preparation of high-order vdW superlattices with larger number of alternating units is exponentially more difficult, owing to the limited yield and material damage associated with each sequential restacking or synthesis step8-29. Here we report a straightforward approach to realizing high-order vdW superlattices by rolling up vdW heterostructures. We show that a capillary-force-driven rolling-up process can be used to delaminate synthetic SnS2/WSe2 vdW heterostructures from the growth substrate and produce SnS2/WSe2 roll-ups with alternating monolayers of WSe2 and SnS2, thus forming high-order SnS2/WSe2 vdW superlattices. The formation of these superlattices modulates the electronic band structure and the dimensionality, resulting in a transition of the transport characteristics from semiconducting to metallic, from 2D to one-dimensional (1D), with an angle-dependent linear magnetoresistance. This strategy can be extended to create diverse 2D/2D vdW superlattices, more complex 2D/2D/2D vdW superlattices, and beyond-2D materials, including three-dimensional (3D) thin-film materials and 1D nanowires, to generate mixed-dimensional vdW superlattices, such as 3D/2D, 3D/2D/2D, 1D/2D and 1D/3D/2D vdW superlattices. This study demonstrates a general approach to producing high-order vdW superlattices with widely variable material compositions, dimensions, chirality and topology, and defines a rich material platform for both fundamental studies and technological applications.

We report the fabrication of polyvinylidene fluoride (tetrabutyl titanate)/polyvinyl pyrrolidone ((tetrabutyl titanate))-graphene quantum dots [PVDF(TBT)/PVP(TBT)-GQDs] film photocatalyst with enhanced photocatalytic performance. The polyvinylidene fluoride (tetrabutyl titanate)/polyvinyl pyrrolidone ((tetrabutyl titanate)) [PVDF(TBT)/PVP(TBT)] film was first prepared with a dual-electrospinning method and then followed by attaching graphene quantum dots (GQDs) to the surface of the composite film through a hydrothermal method. Later, part of the PVP in the composite film was dissolved by a hydrothermal method. As a result, a PVDF(TBT)/PVP(TBT)-GQDs film photocatalyst with a larger specific surface area was achieved. The photocatalytic degradation behavior of the PVDF(TBT)/PVP(TBT)-GQDs film photocatalyst was examined by using Rhodamine B as the target contaminant. The PVDF(TBT)/PVP(TBT)-GQDs photocatalyst showed a higher photocatalytic efficiency than PVDF(TBT)-H2O, PVDF(TBT)/PVP(TBT)-H2O, and PVDF(TBT)-GQDs, respectively. The enhanced photocatalytic efficiency can be attributed to the broader optical response range of the PVDF(TBT)/PVP(TBT)-GQDs photocatalyst, which makes it useful as an effective photocatalyst under white light irradiation.

Ecoregions are distinct groups of natural communities and species. Currently, some ecoregions of the world are considered as vulnerable. Protected areas (PAs) can support the conservation of such vulnerable ecoregions. In this study, global PAs in different International Union for the Conservation of Nature (IUCN) management categories and their vulnerable ecoregions were studied, and human footprint and climate disappearance were assessed. The human footprint was found to drive the ecoregional vulnerability of PAs, which was high for vulnerable ecoregions in Europe, North America, and in smaller regions of Asia, Australia, New Zealand, and South America. These PAs included different biomes (excluding montane grasslands and shrublands) and affected IUCN PA management categories. Discrepancies may exist between observations and the present assignment of PAs to IUCN categories considering the extent of the human footprint; hence, these categories need to be re-evaluated based on human influence. The obtained results indicate that vulnerable ecoregions in forest, tundra, and mangrove biomes in PAs of eastern North America, Europe, south-eastern Asia, Australia, New Zealand, and the Pacific islands face high risks from climate disappearance. The ecoregional vulnerability of PAs to both human influence and climate change was high in temperate broadleaf and mixed forests in south-eastern Asia, Europe, Australia, and New Zealand. For global PAs, we propose that: 1) long-term monitoring should be conducted for changes in temperature and precipitation in vulnerable ecoregions such as forest, tundra, and mangrove biomes; and 2) human influence and climate change are integrated into adaptive strategies for the conservation of vulnerable PA ecoregions.

The advanced treatment of municipal secondary effluent by heterogeneous and homogeneous Fenton processes using Fe/Ce-RGO (reduced graphene oxide) and Fe2+ as catalysts was studied and compared. Sulfamethazine (SMT) was spiked in the effluent to examine the effectiveness of the emerging contaminant removal. The Fe/Ce-RGO catalyst was characterized using a scanning electron microscope (SEM) and cycle voltammetry curves. The removal of dissolved organic carbon (DOC), soluble chemical oxygen demand (SCOD), SMT, and ultraviolet-visible spectroscopy in 254 nm (UV254) of municipal secondary effluents was examined. The DOC removal efficiency of secondary effluent (without addition of SMT) was 36.30% and 11.74% using Fe/Ce-RGO and Fe2+ as catalysts, respectively. The removal efficiency of DOC, SCOD, and SMT in heterogeneous Fenton process was higher than that in homogeneous Fenton process. The changes of three-dimensional excitation-emission matrix (3DEEM) fluorescence, soluble microbial products (SMPs), humic acids, and UV254 were determined, and the results indicated that UV254, aromatic proteins, and humic acids decreased rapidly in both processes; however, polysaccharides and protein-like substances were difficult to degrade. Although some toxic substances produced after Fenton-like treatment, the biodegradability of the treated effluent was enhanced.

Invasive plant species (IPS) have a high potential for expanding within biodiversity hotspots and threatening global plant diversity. Hence, it is urgent to assess the expansion risk of IPS in regions of high plant diversity and their potentially negative effects throughout the world. We used the world's 36 worst IPS as focal study species and applied species distribution modeling to project the suitable habitat distributions of these IPS in centers of plant diversity at the global scale. Subsequently, we assessed the expansion risk of IPS based on habitat suitability across biomes and nature reserves. We found that IPS, particularly Chromolaena odorata, Eichhornia crassipes, Leucaena leucocephala, and Mimosa pigra, have high expansion potential in Tropical & Subtropical Moist Broadleaf Forests, Tropical & Subtropical Dry Broadleaf Forests, and Mangroves within global regions of high plant diversity. Furthermore, IPS such as Imperata cylindrica and L. leucocephala may expand dramatically into Vulnerable and Critical or Endangered biome areas, including nature reserves across Tropical & Subtropical Moist Broadleaf Forests and Tropical & Subtropical Coniferous Forests. We suggest that effective conservation management should be enhanced in order to reduce the expansion risk of IPS in the Vulnerable and Critical or Endangered biome areas, that temperature changes should be carefully monitored, and that conservation policies of nature reserves should be reviewed, particularly regarding IPS with high potential to naturally disperse into the nature reserves.

China has large areas of forest vegetation that are critical to biodiversity and carbon storage. It is important to assess vulnerability of forest vegetation to anthropogenic climate change in China because it may change the distributions and species compositions of forest vegetation. Based on the equilibrium assumption of forest communities across different spatial and temporal scales, we used species distribution modelling coupled with endemics-area relationship to assess the vulnerability of 204 forest communities across 16 vegetation types under different climate change scenarios in China. By mapping the vulnerability of forest vegetation to climate change, we determined that 78.9% and 61.8% of forest vegetation should be relatively stable in the low and high concentration scenarios, respectively. There were large vulnerable areas of forest vegetation under anthropogenic climate change in northeastern and southwestern China. The vegetation of subtropical mixed broadleaf evergreen and deciduous forest, cold-temperate and temperate mountains needleleaf forest, and temperate mixed needleleaf and broadleaf deciduous forest types were the most vulnerable under climate change. Furthermore, the vulnerability of forest vegetation may increase due to high greenhouse gas concentrations. Given our estimates of forest vegetation vulnerability to anthropogenic climate change, it is critical that we ensure long-term monitoring of forest vegetation responses to future climate change to assess our projections against observations. We need to better integrate projected changes of temperature and precipitation into climate-adaptive conservation strategies for forest vegetation in China.

In this paper, an extended nonmonotone line search is proposed to improve the efficiency of the existing line searches. This line search is first proved to be an extension of the classical line search rules. On the one hand, under mild assumptions, global convergence and R-linear convergence are established for the new line search rule. On the other hand, by numerical experiments, it is shown that the line search can integrate the advantages of the existing methods in searching for a suitable step-size. Combined with the spectral step-size, a class of spectral gradient algorithms are developed and employed to solve a large number of benchmark test problems from CUTEst. Numerical results show that the new line search is promising in solving large-scale optimization problems, and outperforms the other similar ones as it is combined with a spectral gradient method.

In this paper, a multiobjective mixed-integer piecewise nonlinear programming model (MOMIPNLP) is built to formulate the management problem of urban mining system, where the decision variables are associated with buy-back pricing, choices of sites, transportation planning, and adjustment of production capacity. Different from the existing approaches, the social negative effect, generated from structural optimization of the recycling system, is minimized in our model, as well as the total recycling profit and utility from environmental improvement are jointly maximized. For solving the problem, the MOMIPNLP model is first transformed into an ordinary mixed-integer nonlinear programming model by variable substitution such that the piecewise feature of the model is removed. Then, based on technique of orthogonal design, a hybrid heuristic algorithm is developed to find an approximate Pareto-optimal solution, where genetic algorithm is used to optimize the structure of search neighborhood, and both local branching algorithm and relaxation-induced neighborhood search algorithm are employed to cut the searching branches and reduce the number of variables in each branch. Numerical experiments indicate that this algorithm spends less CPU (central processing unit) time in solving large-scale regional urban mining management problems, especially in comparison with the similar ones available in literature. By case study and sensitivity analysis, a number of practical managerial implications are revealed from the model.Since the metal stocks in society are reliable overground mineral sources, urban mining has been paid great attention as emerging strategic resources in an era of resource shortage. By mathematical modeling and development of efficient algorithms, this paper provides decision makers with useful suggestions on the optimal design of recycling system in urban mining. For example, this paper can answer how to encourage enterprises to join the recycling activities by government's support and subsidies, whether the existing recycling system can meet the developmental requirements or not, and what is a reasonable adjustment of production capacity.

Global climate change may enable invasive plant species (IPS) to invade protected areas (PAs), but plant invasion on a global scale has not yet been explicitly addressed. Here, we mapped the potential invasion pathways for IPS in PAs across the globe and explored potential factors determining the pathways of plant invasion under climate change. We used species distribution modelling to estimate the suitable habitats of 386 IPS and applied a corridor analysis to compute the potential pathways of IPS in PAs under climate change. Subsequently, we analysed the potential factors affecting the pathways in PAs. According to our results, the main potential pathways of IPS in PAs are in Europe, eastern Australia, New Zealand, southern Africa, and eastern regions of South America and are strongly influenced by changes in temperature and precipitation. Protected areas can play an important role in preventing and controlling the spread of IPS under climate change. This is due to the fact that measures are taken to monitor climate change in detail, to provide effective management near or inside PAs, and to control the introduction of IPS with a high capacity for natural dispersal. A review of conservation policies in PAs is urgently needed.

Current disjunct patterns can result from long‐distance dispersal or postglacial contraction. We herein investigate the evolutionary history of Triplostegia to elucidate the disjunction between the Himalaya–Hengduan Mountain region (HHM) and Taiwan (TW). Genetic structure of Triplostegia was investigated for 48 populations using sequences from five chloroplast loci and the ribosomal nuclear internal transcribed spacer. Divergence time estimation, ancestral area reconstruction, and species distribution modeling (SDM) were employed to examine the biogeographic history of Triplostegia. Substantial genetic differentiation among populations from southwestern China (SW), Central China (CC), and TW was detected. Triplostegia was inferred to have originated in SW, and diversification began during the late Miocene; CC was colonized in the mid‐Pliocene, and TW was finally colonized in the early Pleistocene. SDM suggested an expansion of climatically suitable areas during the Last Glacial Maximum and range contraction during the Last interglacial in Triplostegia. Disjunction between HHM and TW in Triplostegia is most likely the consequence of topographic isolation and postglacial contraction. The potential climatic suitability areas for Triplostegia by 2070s (2061–2080) are predicted to slightly shrink and move northward. With continued global warming and human‐induced deforestation, extinction risk may increase for the cold‐adapted species, and appropriate strategies should be employed for ecosystem conservation.

Human footprint and soil variability may be important in shaping the spread of invasive plant species (IPS). However, until now, there is little knowledge on how human footprint and soil variability affect the potential distribution of IPS in different biomes. We used Maxent modeling to project the potential distribution of 29 IPS with wide distributions and long introduction histories in China based on various combinations of climatic correlates, soil characteristics and human footprint. Then, we evaluated the relative importance of each type of environmental variables (climate, soil and human footprint) as well as the difference in range and similarity of the potential distribution of IPS between different biomes. Human footprint and soil variables contributed to the prediction of the potential distribution of IPS, and different types of biomes had varying responses and degrees of impacts from the tested variables. Human footprint and soil variability had the highest tendency to increase the potential distribution of IPS in Montane Grasslands and Shrublands. We propose to integrate the assessment in impacts of human footprint and soil variability on the potential distribution of IPS in different biomes into the prevention and control of plant invasion.

A number of widespread invasive plants are wind-dispersed, and wind may facilitate their dispersal and migration over a large distance. While wind is an important factor for seed dispersal and pollination, few studies have examined its potential to affect the habitat distribution of invasive plants over large spatial scales. We selected six of the world's worst invasive plants with wind-driving seed dispersal and pollination, and used wind speed as an indicator of wind. Environmental niche modelling was used to quantify the effects of wind on the habitat distribution of these invasive plants on a global scale and across 14 biomes. Wind had a negative effect on the habitat distribution of invasive plants in tropical and subtropical moist biomes, and a positive effect in Temperate Conifer Forests, Boreal Forests/Taiga, Temperate Grasslands, Savannas and Shrublands, and Montane Grasslands and Shrublands. We concluded that wind affected the habitat distribution of wind-dispersed invasive plants over a large scale, and this effect varied across different biomes. Thus, wind speed and biomes should be used as global monitoring indicators of invasion by wind-dispersed plants and wind speed variables should be included in the projection of habitat distributions of such invasive species when using ENM.

We present an extension of vendor-managed inventory (VMI) problems by considering advertising and pricing policies. Unlike the results available in the literature, the demand is supposed to depend on the retail price and advertising investment policies of the manufacturer and retailers, and is a random variable. Thus, the constructed optimization model for VMI supply chain management is a stochastic bi-level programming problem, where the manufacturer is the upper level decision-maker and the retailers are the lower-level ones. By the expectation method, we first convert the stochastic model into a deterministic mathematical program with complementarity constraints (MPCC). Then, using the partially smoothing technique, the MPCC is transformed into a series of standard smooth optimization subproblems. An algorithm based on gradient information is developed to solve the original model. A sensitivity analysis has been employed to reveal the managerial implications of the constructed model and algorithm: (1) the market parameters of the model generate significant effects on the decision-making of the manufacturer and the retailers, (2) in the VMI mode, much attention should be paid to the holding and shortage costs in the decision-making. doi:10.1017/S1446181117000384

(Tb x Y 1−x ) 3 Al 5 O 12 (x = 0.2, 0.5, 0.8) transparent ceramics were synthesized by a solid-state reaction and HIP. All the samples were pre-sintered at 1650 °C for 4 h in a muffle and later HIPed at 1650 °C for 3 h. (Tb 0.2 Y 0.8 ) 3 Al 5 O 12 transparent ceramics exhibit best microstructure with an average grain size of approximately 5.22 μm and optical transmittance of over 65% in the region of 500–1600 nm. Additionally, average grain sizes of all the samples are less than 10 μm. XRD scanning patterns indicate that only the (Tb 0.8 Y 0.2 ) 3 Al 5 O 12 samples have little secondary phases.

Climate change is likely to threaten forests in future. Because dominant tree species (DTS) play central roles in stabilizing forest ecosystems, to effectively protect forests, we need to pay more attention to the protection of DTS. Furthermore, we need to integrate potential impacts of climate change into conservation efforts of DTS for improving forest protection. We utilized species distribution modeling, coupled with conservation planning, to establish climate-informed conservation prioritization for 136 taxa of DTS in three forest types (broad-leaved forests, mixed broadleaf-conifer forests, and coniferous forests) in China. We considered both current and future distributions and assessed the ability of existing nature reserves in China to protect forests based on these DTS. Regions with the highest climate-informed conservation prioritization were distributed in the southern, southwestern, and northeastern regions of China. There was a small gap between existing nature reserves and predicted conservation prioritization areas for conserving forests: the proportions of overlap between existing reserves and areas prioritized under climate change scenarios were 87.8, 95.7, and 80.4% for broad-leaved forests, mixed broadleaf-conifer forests, and coniferous forests, respectively. Even so, we need to increase the number and/or area of nature reserves to protect coniferous forests in Tibet, Sichuan, and Yunnan, and broad-leaved forests in Guizhou, Guangxi, Hu’nan, Yunnan, and Sichuan. Our results demonstrate the importance of conservation planning under climate change, taking both current and future distributions of plant species into consideration. Nature reserves should develop different management strategies for different forest types.

Tb3Al5O12 (TAG) transparent ceramics were prepared by a reactive sintering method using presintering in a muffle furnace combined with hot isostatic pressing (HIP) sintering. The dilatometric, differential scanning calorimetry-thermogravimetric (DSC-TG) curves and optical quality were investigated. The microstructure evolution of the TAG ceramic samples was clarified. Two successive transformations were found to generate a TAG phase, as observed in the dilatometric and DSC-TG curves and XRD patterns of TAG ceramics sintered at different temperature. The changes in average grain size and densification suggest that a 1600°C presintering temperature is suitable for HIP. The optical transmittance of the obtained 0.4 wt% TEOS:TAG transparent ceramics, which were fabricated by a new two-step sintering of presintering at 1600°C in a muffle furnace followed by HIP at 1650°C, can reach above 80% in the visible (vis) and near-infrared (NIR) regions. Its transmittance was very close to the theoretical limit. To the best of our knowledge, this is the first time that TAG transparent ceramics with ideal optical quality were obtained without vacuum sintering.

In this paper, a new spectral residual method is proposed to solve systems of large-scale nonlinear equations, where the steplength is obtained by minimizing the residue of an approximate secant equation. Especially, the new steplength can be directly applied into solving strictly convex quadratic function. Combined with a new nonmonotone line search strategy, a new derivative-free algorithm, called a nonmonotone spectral residual algorithm (NSRA), is developed. Under mild assumptions, global convergence is established for locally Lipschitz continuous nonlinear systems. Compared with the state-of-the-art algorithms available in the literatures, the new algorithm is more efficient in solving large-scale benchmark test problems.

Climate change may increase expansion risk of invasive tree plants (ITPs) worldwide. Ecoregions are the power conservation tool for the management of ITPs. However, few studies have investigated the relationship between ITP expansion and ecoregions at the global scale under climate change scenarios. Here, we provided a method to evaluate the expansion potential of 54 representative ITPs in ecoregions specifically under influences of the changing climate at the global scale. We found that climate change due to increasing greenhouse gas (GHG) concentration plays a positive role on the expansion of ITPs. We determined two of the most important ecoregion hotspots of ITP expansion potential, such as New Zealand and South Africa. In addition, ITPs were likely to have a large potential to expand in ecoregions of five different biomes, like temperate broadleaf and mixed forests. The potential expansion of ITPs would increase obviously in ecoregions of Boreal Forests/Taiga and Tundra. More importantly, the ecoregions of high elevation belonging to Tropical and Subtropical Coniferous Forests were expected to experience the higher expansion risk in the low GHG concentration scenario. Given our estimates of ITP expansion for ecoregions, management for the prevention and control for ITPs is urgent at the global scale.

In this paper, Fe 3 O 4 –Mn 3 O 4 /reduced graphene oxide (RGO) hybrid was synthesized through polyol process and impregnation method and used as heterogeneous Fenton-like catalyst for degradation of sulfamethazine (SMT) in aqueous solution. The hybrid catalyst had higher catalytic efficiency compared with Fe 3 O 4 –Mn 3 O 4 and Mn 3 O 4 as catalyst for degradation of SMT . The effects of pH value, H 2 O 2 concentration, catalyst dosage, initial SMT concentration and temperature on SMT degradation were investigated. The removal efficiency of SMT was about 98% at following optimal conditions: pH = 3, T = 35 °C, Fe 3 O 4 /Mn 3 O 4 -RGO composites = 0.5 g/L, H 2 O 2 = 6 mM. The inhibitor experiments indicated that the main active species was hydroxyl radicals (·OH) on catalyst surface. At last, the possible catalytic mechanism was proposed.

Many biological conservationists take actions to conserve plant species with extremely small populations (PSESP) in China; however, there have been few studies on the spatial distribution of threats to PSESP. Hence, we selected distribution data of PSESP and made a map of the spatial distribution of threats to PSESP in China. First, we used the weight assignment method to evaluate the threat risk to PSESP at both country and county scales. Second, we used a geographic information system to map the spatial distribution of threats to PSESP, and explored the threat factors based on linear regression analysis. Finally, we suggested some effective conservation options. We found that the PSESP with high values of protection, such as the plants with high scientific research values and ornamental plants, were threatened by over-exploitation and utilization, habitat fragmentation, and a small sized wild population in broad-leaved forests and bush fallows. We also identified some risk hotspots for PSESP in China. Regions with low elevation should be given priority for ex- and in-situ conservation. Moreover, climate change should be considered for conservation of PSESP. To avoid intensive over-exploitation or utilization and habitat fragmentation, in-situ conservation should be practiced in regions with high temperatures and low temperature seasonality, particularly in the high risk hotspots for PSESP that we proposed. Ex-situ conservation should be applied in these same regions, and over-exploitation and utilization of natural resources should be prevented. It is our goal to apply the concept of PSESP to the global scale in the future.

Enhancer of Zeste Homolog 2 (EZH2) is highly expressed in kinds of malignant tumors and related to tumor occurrence, development, and prognosis. EZH2 is the catalytic subunit of the polycomb repressive complex 2 (PRC2), which promotes cell proliferation, migration, and invasion by epigenetic regulation of anti-tumor gene. It can activate numerous tumor-associated signaling pathways and interfere with DNA damage repair. In recent years, large amounts of studies have shown that EZH2 is closely related to gynecologic-related malignancies and can be used as a potential target gene for the treatment of gynecological-related malignancies. This review summarizes the oncogenic function of EZH2 and introduces the recent advances in the development of EZH2 inhibitors. On this basis, future research prospect of EZH2 is proposed.

The development of new hypotheses can promote the explanation of mechanisms on plant invasion across different scales. We tested the hypothesis that ecoregional vulnerability can affect habitat suitability of invasive alien plants (IAPs) in non-native ranges. We used 13 IAPs, distributed around the world, and identified vulnerable ecoregions belonging to different biomes and biogeographical realms. Then, Maxent modeling was used to assess the habitat suitability of IAPs. We quantified the effects of ecoregional vulnerability on habitat suitability of IAPs as effect sizes using the log response ratio of habitat suitability. Ecoregional vulnerability had significant effects on habitat suitability for IAPs in invasive ranges across different biomes and biogeographical realms. Such effects may depend on the biomes and biogeographical realms of interest. Ecoregional vulnerability had positive effects on the habitat suitability of Chromolaena odorata, Clidemia hirta, Imperata cylindrica, Melaleuca quinquenervia, Mikania micrantha, Prosopis glandulosa, Rubus ellipticus, and Tamarix ramosissima. Vulnerable ecoregions of tropical and subtropical moist broadleaf forests and temperate broadleaf and mixed forests could result in large distributions and the highest habitat suitability of IAPs. The vulnerable ecoregions were mainly distributed in the biogeographical realms of Australasia, Nearctic, Neotropics, and Oceania. We tested a new hypothesis on disturbances and biological diversity based on ecoregional vulnerability over large scales. Our findings support the hypothesis that ecoregional vulnerability can increase habitat suitability of IAPs, promoting IAPs to expand in invasive ranges. Our study provides insight into the development of new hypotheses on the mechanisms of plant invasion over large scales.

Multiple structural phases in transition metal dichalcogenides have attracted considerable recent interest for their tunable chemical and electronic properties. Herein, a chemical vapor deposition route to ultrathin CoSe nanoplates with tunable structure phases is reported. By precisely tailoring the growth temperature, ultrathin 2D layered tetragonal CoSe nanoplates and nonlayered hexagonal CoSe nanoplates can be selectively prepared as square or hexagonal geometries, with thickness as thin as 2.3 and 3.7 nm, respectively. X-ray diffraction, transmission electron microscopy, and selected area electron diffraction studies show that both types of nanoplates are high-quality single crystals. Electrical transport studies reveal that both the tetragonal and hexagonal CoSe nanoplates show strong thickness-tunable electrical properties and excellent breakdown current density. The 2D hexagonal CoSe nanoplates display metallic behavior with an excellent conductivity up to 6.6 × 105 S m-1 and an extraordinary breakdown current density up to 3.9 × 107 A cm-2 , while the square tetragonal nanoplates show considerably lower conductivity up to 8.2 × 104 S m-1 with angle-dependent magnetoresistance and weak antilocalization effect at lower field. This study offers a tunable material system for exploring multiphase 2D materials and their potential applications for electronic and magnetoelectronic devices.

(Tb0.6Y0.4)3Al5O12 transparent ceramics were successfully fabricated by solid-state reactive sintering using Tb4O7, Y2O3, and &alpha, Al2O3 powders as raw materials. The effect of (Tb+Y)/Al ratio on microstructure evolution and densification process was investigated in detailed. The results showed that the grain growth kinetics were significantly affected by (Tb+Y)/Al ratio. Al-rich and Tb-rich phases appeared in part of the samples of different ratios. Particularly, excess aluminum increased the diffusing process, leading to a higher densification rate, while samples with excess terbium ratios displayed a smaller grain size and lower relative density. The optical quality was highly related to the amount of the secondary phase produced by different (Tb+Y)/Al ratios. Finally, (Tb0.6Y0.4)3Al5O12 transparent ceramics have been fabricated through pre-sintering in vacuum, followed by hot isostatic sintering (HIP), and the best transmittance of sample with a 4 mm thickness was approximately 78% at 1064 nm.

With rapid development of technology and improvement of living standards, the per capita holding of automobiles greatly increases, and the amount of end-of-life vehicles (ELVs) becomes larger and larger such that it is valuable to investigate an effective strategy for recycling ELVs from the viewpoints of environmental protection and resource utilization. In this paper, an optimization model with fuzzy and stochastic parameters is built to formulate the transportation planning problems of recycling ELVs in polymorphic uncertain environment, where the unit processing and transportation costs, the selling price of reused items, and the fixed cost are all fuzzy, while the demand in secondary market and the production capacity are random owing to features underlying the practical data. For this complicated polymorphic uncertain optimization model, a unified compromising approach is proposed to hedge the uncertainty of this model such that some powerful optimization algorithms can be applied to make an optimal recycling plan. Then, an interactive algorithm is developed to find a compromising solution of the uncertain model. Numerical results show efficiency of the algorithm and a number of important managerial insights are revealed from the proposed model by scenario analysis and sensitivity analysis.

In this paper, we develop an algorithm to solve nonlinear system of monotone equations, which is a combination of a modified spectral PRP (Polak-Ribière-Polyak) conjugate gradient method and a projection method. The search direction in this algorithm is proved to be sufficiently descent for any line search rule. A line search strategy in the literature is modified such that a better step length is more easily obtained without the difficulty of choosing an appropriate weight in the original one. Global convergence of the algorithm is proved under mild assumptions. Numerical tests and preliminary application in recovering sparse signals indicate that the developed algorithm outperforms the state-of-the-art similar algorithms available in the literature, especially for solving large-scale problems and singular ones.

Recovery of waste electrical and electronic equipment (WEEE) plays an important role in protecting environment and conserving resources. Design of a more efficient WEEE recovery system is an imperative need for the relevant decision-makers, such as alleviation of overcapacity or insufficient recycling in many developing countries. In this paper, we optimize the WEEE recovery network which is associated with recycling prices and government subsidies by a nonlinear mixed integer programming approach. An integrated model is first proposed to formulate a design problem of WEEE recovery network, being involved with collection centers, two types of transfer stations, processing centers, incineration plants, landfill plants, secondhand product markets, and government subsides. The recycling prices and the transported quantities of WEEE (the number of batches) are endogenous variables of the model, being subject to a number of practical constraints. For solving this model, an algorithm is developed based on the branch and bound method. Scenario analysis and numerical experiments indicate that: (1) appropriate capacities of transfer stations can be provided by the proposed model for designing an environmentally and economically efficient WEEE recycling system, especially for alleviating the existing overcapacity or insufficient recycle. (2) An optimal governmental subsidy can be obtained in virtue of the proposed model and algorithm. (3) Diversity of transportation modes and permission of more than one mode in the same delivery route can greatly reduce the cost of recycling WEEE. (4) Preferred awareness of environmental protection can increase the profit and the recycled quantities, as well as reduction of the total recycling cost.

In this paper, we develop two algorithms to solve a nonlinear system of symmetric equations. The first is an algorithm based on modifying two Broyden–Fletcher–Goldfarb–Shanno (BFGS) methods. One of its advantages is that it is more suitable to effectively solve a small-scale system of nonlinear symmetric equations. In contrast, the second algorithm chooses new search directions by incorporating an approximation method of computing the gradients and their difference into the determination of search directions in the first algorithm. In essence, the second one can be viewed as an extension of the conjugate gradient method recently proposed by Lv et al. for solving unconstrained optimization problems. It was proved that these search directions are sufficiently descending for the approximate residual square of the equations, independent of the used line search rules. Global convergence of the two algorithms is established under mild assumptions. To test the algorithms, they are used to solve a number of benchmark test problems. Numerical results indicate that the developed algorithms in this paper outperform the other similar algorithms available in the literature.