Imidacloprid reduces the mating success of males in bumblebees.

Bumblebees play a vital role in both natural and agricultural environments, but there has been a noticeable decline in their populations. Pesticides, particularly neonicotinoids, are widely regarded as a substantial contributing factor to the decline in bumblebee populations, as evidenced by the detrimental impacts documented across many stages of their life cycle. Mating is vital for the population maintenance of bumblebees. Nevertheless, there is a scarcity of research conducted on the effects of pesticides on the mating process. In this study, we individually examined the impact of imidacloprid on the mating behavior of bumblebee males and queens. A competitive mating experiment was conducted to evaluate the effect on the competitive prowess of male individuals and the mate selection behavior of female individuals. The study revealed that the mating rate of bumblebees exposed to a concentration of 10 ppb of imidacloprid was 3 %. This finding demonstrated a statistically significant impact when compared to the control group, which exhibited a mating rate of 58 % in the normal mating experiment. Furthermore, in the competitive mating experiment, we found that the competitive mating success rate of treated males (1 %) was significantly lower than that of untreated males (35 %). Hence, it provides evidence that neonicotinoid imidacloprid negatively affects bumblebee mating success and cautions us to protect bumblebees from pesticide exposure to prevent a severe impact on their populations.

Conservation genomics analysis reveals recent population decline and possible causes in bumblebee Bombus opulentus.

Bumblebees are a genus of pollinators (Bombus) that play important roles in natural ecosystem and agricultural production. Several bumblebee species have been recorded as under population decline, and the proportion of species experiencing population decline within subgenus Thoracobombus is higher than average. Bombus opulentus is 1 species in Thoracobombus, but little is known about its recent population dynamics. Here, we employed conservation genomics methods to investigate the population dynamics of B. opulentus during the recent past and identify the likely environmental factors that may cause population decline. Firstly, we placed the scaffold-level of B. opulentus reference genome sequence onto chromosome-level using Hi-C technique. Then, based on this reference genome and whole-genome resequencing data for 51 B. opulentus samples, we reconstructed the population structure and effective population size (Ne ) trajectories of B. opulentus and identified genes that were under positive selection. Our results revealed that the collected B. opulentus samples could be divided into 2 populations, and 1 of them experienced a recent population decline; the declining population also exhibited lower genetic diversity and higher inbreeding levels. Genes related to high-temperature tolerance, immune response, and detoxication showed signals of positive selection in the declining population, suggesting that climate warming and pathogen/pesticide exposures may contribute to the decline of this B. opulentus population. Taken together, our study provided insights into the demography of B. opulentus populations and highlighted that populations of the same bumblebee species could have contrasting Ne trajectories and population decline could be caused by a combination of various stressors.

Pan-genome analysis highlights the role of structural variation in the evolution and environmental adaptation of Asian honeybees.

The Asian honeybee, Apis cerana, is an ecologically and economically important pollinator. Mapping its genetic variation is key to understanding population-level health, histories and potential capacities to respond to environmental changes. However, most efforts to date were focused on single nucleotide polymorphisms (SNPs) based on a single reference genome, thereby ignoring larger scale genomic variation. We employed long-read sequencing technologies to generate a chromosome-scale reference genome for the ancestral group of A. cerana. Integrating this with 525 resequencing data sets, we constructed the first pan-genome of A. cerana, encompassing almost the entire gene content. We found that 31.32% of genes in the pan-genome were variably present across populations, providing a broad gene pool for environmental adaptation. We identified and characterized structural variations (SVs) and found that they were not closely linked with SNP distributions; however, the formation of SVs was closely associated with transposable elements. Furthermore, phylogenetic analysis using SVs revealed a novel A. cerana ecological group not recoverable from the SNP data. Performing environmental association analysis identified a total of 44 SVs likely to be associated with environmental adaptation. Verification and analysis of one of these, a 330 bp deletion in the Atpalpha gene, indicated that this SV may promote the cold adaptation of A. cerana by altering gene expression. Taken together, our study demonstrates the feasibility and utility of applying pan-genome approaches to map and explore genetic feature variations of honeybee populations, and in particular to examine the role of SVs in the evolution and environmental adaptation of A. cerana.

Pesticide residues in beebread and honey in Apis cerana cerana and their hazards to honey bees and human.

The residue of pesticides in bee products such as beebread and honey threaten the survival of pollinators and human health. Apis cerana cerana is one of the leading managed honey bees in China. However, little is known about the residues of pesticides in hive products of A. c. cerana in China. Here, we investigated the pesticide residues in beebread and honey. The risk of detected residues of pesticides to honey bees was evaluated with hazard quotient (HQ) and BeeREX. Furthermore, we assessed the chronic and acute risks to humans according to the dietary exposure. Our results suggest that the pesticide residues detection ratio (25.4% for beebread and 2.8% for honey) and the concentrations of these residues is lower than previously reported. Additional risk assessments indicate that the residue levels of pesticides in tested honey of A. c. cerana do not pose a risk for human consumers. Among all identified pesticides, only thiamethoxam raises the concern for further risk assessment in the risk evaluation of honey bee colonies and thiamethoxam was safe for colonies in higer tier studies.

Assessing the toxicological interaction effects of imidacloprid, thiamethoxam, and chlorpyrifos on Bombus terrestris based on the combination index.

In modern agricultural production, a variety of pesticides are widely used to protect crops against pests. However, extensive residues of these pesticides in the soil, water, and pollen have negatively affected the health of nontarget organisms, especially among pollinators such as bumblebees. As an important pollinator, the bumblebee plays a vital role in agricultural production and the maintenance of ecosystem diversity. Previous research has focused on the effects of a single pesticide on pollinating insects; however, the synergistic effects of multiple agents on bumblebees have been not studied in detail. Imidacloprid, thiamethoxam, and chlorpyrifos are three of common pesticides known for severe effects on bumblebee health. It is still unknown what synergistic effects of these pesticides on pollinators. In our test, the individual and combined toxicities of chlorpyrifos, thiamethoxam, and imidacloprid to bumblebees after 48 h of oral administration were documented by the equivalent linear equation method. Our results showed that the toxicity of each single pesticide exposure, from high to low, was imidacloprid, thiamethoxam, and chlorpyrifos. All binary and ternary combinations showed synergistic or additive effects. Therefore, our research not only shows that the mixed toxicity of insecticides has a significant effect on bumblebees, but also provides scientific guidelines for assessing the safety risks to bumblebees of these three insecticide compounds. In assessing the risk to pollinating insects, the toxicity levels of laboratory experiments are much lower than the actual toxicity in the field.

Pesticide residues in the pollen and nectar of oilseed rape (Brassica napus L.) and their potential risks to honey bees.

Research evidence suggests that pesticide residues are one of the leading potential causes of the decline in pollinators, especially during vulnerable periods such as foraging in the early springtime. In China, no research quantifies pesticide residues in the nectar and pollen of honey bee colonies during this period or examines the potential risks and toxicity of pesticides to honey bees. Oilseed rape is one of the first and primary bee-attractive plants in most parts of China. Here, we investigated the pesticide residues in the oilseed rape of the years 2017 and 2018 in China. The hazard quotient (HQ) from pollen and nectar and the BeeREX risk assessment were used to evaluate the potential risks of the pesticide residues to honey bees. We detected 48 pesticides in pollen samples and 34 chemicals in nectar samples. The maximum pollen HQ (PHQ) values (contact or oral) ranged from 0.16 to 706,421, and the maximum nectar HQ (NHQ) values (contact or oral) ranged from 0.07 to 185,135. In particular, carbofuran, cyfluthrin, deltamethrin, and fenpropathrin have relatively high PHQ and NHQ values. Our results indicated that further investigation of nearly half of the tested compounds is needed because their PHQ or NHQ values are more than 50. Especially cyfluthrin and carbofuran need advanced tier assessment due to their maximum RQ (risk quotient) values exceeding the level of concern. These results provide valuable guidance for protecting bees and other pollinators in China.

Diagnostic indicators of wild pollinators for biodiversity monitoring in long-term conservation.

For the conservation of wild pollinators, instead of surveying the whole community, one or more indicator species can be used as monitoring targets for long-term conservation. China, the richest country in terms of bumblebee species with 125 species, was selected here to investigate the indicator species of the different biogeographic regions of bumblebees. Four principal biogeographic regions of bumblebee species, i.e., South China, North-Northeast China (North China), the Mongolian Plateau and surrounding mountains (Mongolian Plateau) and the Tibetan Plateau and surrounding mountains (Tibetan Plateau), were revealed by Ward's agglomerative cluster analysis. The role of climatic factors in defining the biogeographic regions was found to be greater than those of topographical factors and their joint effects. We found that 14, 13, 12 and 12 species were associated with the regions of South China, North China, the Mongolian Plateau and the Tibetan Plateau, respectively. In addition, among these species, seven (Bombus atripes, B. bicoloratus, B. breviceps, B. eximius, B. flavescens, B. montivagus and B. trifasciatus), five (B. deuteronymus, B. patagiatus, B. pseudobaicalensis, B. tricornis and B. ussurensis), ten (B. armeniacus, B. confusus, B. cryptarum, B. cullumanus, B. hortorum, B. muscorum, B. ruderarius, B. soroeensis, B. subterraneus and B. terrestris) and four species (B. kashmirensis, B. personatus, B. rufofasciatus and B. waltoni) were identified as important indicator species for South China, North China, the Mongolian Plateau and the Tibetan Plateau, respectively. Furthermore, we identified specific areas for targeted bumblebee diversity monitoring in each region. This study highlights the bioregionalization and the identification of indicator species of bumblebee pollinators for long-term monitoring in conservation.

Impact of acute oral exposure to thiamethoxam on the homing, flight, learning acquisition and short-term retention of Apis cerana.

BACKGROUND: Thiamethoxam (TMX) represents the second generation of neonicotinoids that has been widely applied in agricultural activities, while how TMX alters the behavior of Apis cerana, an important native honey bee species in China, is not clear. We carried out three independent experiments to study the impact of acute oral treatment of 20 µL TMX at concentrations of 2.4 ppb (0.048 ng/bee) and 10 ppb (0.2 ng/bee) on the homing, flight, learning acquisition and short-term retention ability of A. cerana. The homing ability was assessed by the catch-and-release method, the flight ability was assessed by flight mills, and the learning acquisition and short-term retention were evaluated by the proboscis extension response method. RESULTS: When treated with 10 ppb of TMX, bees had a significantly higher average homing time, mean flight velocity, flying distance, and flying duration than the control, whereas 2.4 ppb concentration did not cause any significant effect on homing or flight ability. Bees treated with either 2.4 ppb or 10 ppb TMX had significantly lower learning acquisition and short-term retention ability. CONCLUSION: Results suggest that acute oral exposure to 10 ppb of TMX altered the short-distance homing time, flight ability, and learning acquisition and short-term retention ability. Our study also highlights the concern that acute oral exposure to a low concentration of 2.4 ppb could have consequences on the behavior of A. creana. Those multiple sublethal alterations on A. cerana's behavior indicate that TMX are likely having complex but negative consequences on bee health in the field. © 2019 Society of Chemical Industry.

Broad-complex Z3 contributes to the ecdysone-mediated transcriptional regulation of the vitellogenin gene in Bombus lantschouensis.

During reproduction, vitellogenin (Vg), as an egg yolk precursor, is critical in sexually mature females of oviparous species including some insects. The transcription of Vg is usually mediated by hormones such as juvenile hormone (JH), ecdysteroids and some neuropeptides. In this study, the structure of the Vg gene from the bumblebee Bombus lantschouensis, (BlVg) was determined by sequencing and assembly. BlVg was found to be expressed at higher levels in reproductive queens than in virgins by quantitative real-time PCR analysis. Tissue-specific expression analysis showed that BlVg was expressed at the highest levels in the fat bodies of both virgin and reproductive queens. Prediction of the BlVg promoter revealed the presence of ecdysteroid-responsive cis-regulatory elements (CREs) containing one Broad-Complex zinc-finger isoform 3 (BR-C Z3), and one ecdysone-induced protein 74A (E74A). In addition, luciferase reporter expression, driven by the 5' -regulatory region of the BlVg gene, from -1517 bp to +895 bp downstream of the start codon, was induced by treatment with 20-hydroxyecdysone (20-E). Moreover, the luciferase activity of the BlVg promoter was elevated by only BlBrC-Z3 when Sf9 cells were cotransfected with four BlBrC isoforms respectively. BlVg promoter-mediated luciferase activation was significantly reduced when the putative BrC-Z3 CRE in the promoter was mutated. In summary, this report describes the first study of vitellogenin gene regulation at the transcriptional level in bumblebees and demonstrates that the ecdysone-induced transcription of the BlVg gene is mediated by the binding of BlBrC-Z3 to the BrC-Z3 CRE in the BlVg promoter in bumblebees.

Pollen trapping and sugar syrup feeding of honey bee (Hymenoptera: Apidae) enhance pollen collection of less preferred flowers.

Pear (Pyrus bretschneideri) is characterized by being self-incompatible and dependent on cross-pollination to set fruit. Honeybee (Apis mellifera) is considered the most important pollinator of pear. Nevertheless, limited pollen transfer has been cited as the main cause of poor fruit set in many pear orchards. Here, we tested the following hypotheses: (i) colony manipulations increase the pollen collection tendency of honeybees and (ii) the proportion of pollen loads being returned to the hive is from the target plant. The technique reliably and rapidly estimates the pollination of honeybees tested under different colony manipulations: (1) using pollen trapping (PT); (2) PT with sugar syrup feeding (SS) (PTSS); (3) SS alone and (4) control without PT and SS. The results clearly show that the pollen collection of honeybees during the experiment was significantly affected (P < 0.05) by colony manipulations. The mean amount of pollen harvested daily was higher for PTSS (19.4 g) and PT (16.4 g) than for SS (12.85 g) and control (8.7 g) colonies. Therefore, PTSS was the most effective treatment for increasing pear pollen collection; other treatments such as PT and SS could also be useful. This study was important for determining how the behavior of honeybee colonies is shaped through colony manipulation to enhance pollen collection of less preferred pear flowers, which is critical when pollination is required.

Apis cerana Is Less Sensitive to Most Neonicotinoids, Despite of Their Smaller Body Mass.

Multiple stressors and interaction between them may be responsible for the decline of global pollinators. Among them, exposure to neonicotinoids has been getting more attention and has been considered as a main stressor. The Western honey bee (Apis mellifera L.) (Hymenoptera: Apidae) and Chinese indigenous honey bee (Apis cerana F.) (Hymenoptera: Apidae) are two managed honey bee species in China. These two species are widely used in beekeeping, and many wild A. cerana is widely spread in forests and contributes to the ecosystem. It is predicated that A. cerana is more sensitive to insecticides than A. mellifera due to their smaller mass. Here, we found that although the body mass of A. cerana is significantly lower than A. mellifera, the sensitivity of the two species to neonicotinoids are not associated with their body mass but depended on the chemical structure of neonicotinoids. To dinotefuran, the two species showed the similar sensitivity. To acetamiprid, A. mellifera was less sensitive than A. cerana. However, to imidacloprid and thiamethoxam, A. mellifera was more sensitive than A. cerana. These results suggested that the sensitivity of honey bees to neonicotinoids is closely associated with the structure of pesticides, but not with body mass of bees. It is also indicated that the hazards of pesticides to the different pollinators could not be inferred from one species to another.

NDUFA4L2 is associated with clear cell renal cell carcinoma malignancy and is regulated by ELK1.

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is the most common and lethal cancer of the adult kidney. However, its pathogenesis has not been fully understood till now, which hinders the therapeutic development of ccRCC. NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4-like 2 (NDUFA4L2) was found to be upregulated and play an important role in ccRCC. We aimed to further investigate the underlying mechanisms by which NDUFA4L2 exerted function and its expression level was upregulated. METHODS: The Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) data were mined to verify the change of NDUFA4L2 expression level in ccRCC tissues. The correlation between expression level of NDUFA4L2 and cell proliferation/apoptosis was explored by Gene Set Enrichment Analysis (GSEA). Protein-protein interaction (PPI) network of NDUFA4L2 was constructed. Biological process and involved pathways of NDUFA4L2 were analyzed by gene ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway. The transcription factors (TFs) which can induce the expression of NDUFA4L2 were explored in clinical samples by correlation analysis and its regulation on the expression of NDUFA4L2 was verified by knockdown experiment. RESULTS: NDUFA4L2 was verified to be overexpressed in ccRCC tissues and its expression level was increased accordingly as the American Joint Committee on Cancer (AJCC) stage progressed. A high NDUFA4L2 level predicted the poor prognosis of ccRCC patients and correlated with enhanced cell proliferation and anti-apoptosis. NDUFA4L2 may interact with 14 tumor-related proteins, participate in growth and death processes and be involved in ccRCC-related pathways, such as insulin-like growth factor 1 (IGF-1), mammalian target of Rapamycin (mTOR) and phosphoinositide 3 kinase serine/threonine protein kinase (PI3K/AKT). ETS domain-containing protein ELK1 level positively correlated with the level of NDUFA4L2 in ccRCC tissues and ELK1 could regulate the expression of NDUFA4L2 in ccRCC cells. DISCUSSION: NDUFA4L2 upregulation was associated with ccRCC malignancy. NDUFA4L2 expression was regulated by ELK1 in ccRCC cells. Our study provided potential mechanisms by which NDUFA4L2 affected ccRCC occurrence and progression.

Wild pollinators enhance oilseed rape yield in small-holder farming systems in China.

BACKGROUND: Insect pollinators play an important role in crop pollination, but the relative contribution of wild pollinators and honey bees to pollination is currently under debate. There is virtually no information available on the strength of pollination services and the identity of pollination service providers from Asian smallholder farming systems, where fields are small, and variation among fields is high. We established 18 winter oilseed rape (Brassica napus L.) fields along a large geographical gradient in Jiangxi province in China. In each field, oilseed rape plants were grown in closed cages that excluded pollinators and open cages that allowed pollinator access. The pollinator community was sampled by pan traps for the entire oilseed rape blooming period. RESULTS: Oilseed rape plants from which insect pollinators were excluded had on average 38% lower seed set, 17% lower fruit set and 12% lower yield per plant, but the seeds were 17% heavier, and the caged plants had 28% more flowers and 18% higher aboveground vegetative biomass than plants with pollinator access. Oilseed rape plants thus compensate for pollination deficit by producing heavier seeds and more flowers. Regression analysis indicated that local abundance and diversity of wild pollinators were positively associated with seed set and yield/straw ratio, while honey bee abundance was not related to yield parameters. CONCLUSIONS: Wild pollinator abundance and diversity contribute to oilseed rape yield by enhancing plant resource allocation to seeds rather than to above-ground biomass. This study highlights the importance of the conservation of wild pollinators to support oilseed rape production in small-holder farming systems in China.

Cross-resistance studies of Cry1Ac-resistant strains of Helicoverpa armigera (Lepidoptera: Noctuidae) to Cry2Ab.

Bioassays and binding tests between Cry toxins (CrylAa, CrylAb, CrylAc, and Cry2Ab) and brush-border membrane vesicles (BBMVs) from larvae of a Bacillus thurningiensis (Bt)-susceptible (96S) and two CrylAc-resistant strains (BtR and LFR10) were conducted for investigating cross-resistance of CrylAc-resistant strains to Cry2Ab in Helicoverpa armigera (Hiibner) (Lepidoptera: Noctuidae). The resistance ratio (RR) values of the BtR and LFR10 strains to CrylAc and Cry2Ab were 2,971- and 1.1-fold and 253- and 1.0-fold, respectively, indicating that there was no cross-resistance to Cry2Ab. The binding experiments between Cry toxins and BBMVs from BtR, LFR10, and 96S larvae showed that all of the toxins could bind with these BBMVs, but the Cry2Ab could not displace 125I labeled CrylAc and CrylAb. The same results were observed in reciprocal binding tests, demonstrating that CrylA and Cry2Ab had different binding sites in H. armigera and providing a potential mechanism for the lack of cross-resistance between CrylA and Cry2Ab toxins. These results suggest that the transgenic cotton, Gossypium hirsutum L., expressing CrylAc and Cry2Ab genes may be deployed for management of CrylAc resistant H. armigera.

Batchwise growth of silica cone patterns via self-assembly of aligned nanowires.

Silica-cone patterns self-assembled from well-aligned nanowires are synthesized using gallium droplets as the catalyst and silicon wafers as the silicon source. The cones form a triangular pattern array radially on almost the whole surface of the molten Ga ball. Detailed field-emission scanning electron microscopy (SEM) analysis shows that the cone-pattern pieces frequently slide off and are detached from the molten Ga ball surface, which leads to the exposure of the catalyst surface and the growth of a new batch of silicon oxide nanowires as well as the cone patterns. The processes of growth and detachment alternate, giving rise to the formation of a volcano-like or a flower-like structure with bulk-quantity pieces of cone patterns piled up around the Ga ball. Consequently, the cone-patterned layer grows batch by batch until the reaction is terminated. Different to the conventional metal-catalyzed growth model, the batch-by-batch growth of the triangular cone patterns proceeds on the molten Ga balls via alternate growth on and detachment from the catalyst surface of the patterns; the Ga droplet can be used continuously and circularly as an effective catalyst for the growth of amorphous SiO(x) nanowires during the whole growth period. The intriguing batchwise growth phenomena may enrich our understanding of the vapour-liquid-solid (VLS) growth mechanism for the catalyst growth of nanowires or other nanostructures and may offer a different way of self-assembling novel silica nanostructures.

Structural, magnetic, and magnetoresistive properties of electrodeposited Ni5Zn21 alloy nanowires.

Ni5Zn21 alloy nanowires were fabricated through template-assisted electrochemical deposition method. The morphology and microstructures of as-deposited nanowires were determined by field-emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), high-resolution transmission electron microscope (HRTEM), electron diffraction (ED), and electron probe microanalysis (EPMA). The accurate composition was measured via induced coupling plasma atomic emission spectroscopy. SEM results show that Ni5Zn21 nanowires are deposited in most of the nanopores of the template, and they are continuous and dense throughout the whole length. The XRD result demonstrates that the nanowires are mainly composed of a cubic gamma phase Ni5Zn21 alloy, but there also exists a trace of Zn-rich eta phase. HRTEM and ED reveal that the alloy nanowires are polycrystalline with the crystallite size of several tens of nanometers. EPMA of a single nanowire illustrates that there exist Ni-rich microzones in as-deposited nanowires. Subsequent magnetic measurements of the array also confirmed the existence of them. In addition, it can be further inferred that the shape of Ni-rich microzones is probably barlike or disklike, from the anisotropy of zero field cooling/field cooling (ZFC/FC) curves as well as the vortex magnetization behavior of the Ni5Zn21 nanowire array. The low-temperature magnetoresistance of the Ni5Zn21 nanowire array was also measured. Giant magnetoresistance instead of anisotropic magnetoresistance is suggested to be responsible for contributing to the magnetoresistance.

Growth mechanism, photoluminescence, and field-emission properties of ZnO nanoneedle arrays.

ZnO nanoneedle arrays have been grown on a large scale with a chemical vapor deposition method at 680 degrees C. Zn powder and O(2) gas are employed as source materials, and catalyst-free Si plates are used as substrates. Energy-dispersive X-ray and X-ray diffraction analyses show that the nanoneedles are almost pure ZnO and preferentially aligned in the c-axis direction of the wurtzite structure. The growth mechanism of ZnO nanoneedle arrays is discussed with the thermodynamic theory and concluded to be the result of the co-effect of the surface tension and diffusion. Photoluminescence spectrum of the as-grown products shows a strong emission band centering at about 484 nm, which originates from oxygen vacancies. Field-emission examination exhibits that the ZnO nanoneedle arrays have a turn-on voltage at about 5.3 V/microm.

Synthesis of long indium nitride nanowires with uniform diameters in large quantities.

Large quantities of indium nitride (InN) nanowires are synthesized by the in situ nitriding of indium oxide (In(2)O(3)) powders in an ammonia (NH(3)) flux. Tens of milligrams of nanowires are obtained in one batch. Every 100 mg of In(2)O(3) starting powder can produce up to 65 mg of InN nanowires under the optimized conditions. The synthesized nanowires grow along the [001] direction with excellent crystallinity. They are of high purity and are 30-50 microm in length with an almost uniform diameter of about 100 nm. Photoluminescence measurements of the nanowires exhibit a strong peak at 707 nm. An optical bandgap of about 1.7 eV is estimated based on the absorption spectrum. The experimental results also demonstrate that the approach of nitriding In(2)O(3) powders in situ is feasible for the synthesis of high-purity InN nanowires in large quantities, with good reproducibility and without catalyst materials. The synthesis of InN nanowires in large quantities would be of benefit to the further study and understanding of their intrinsic properties, as well as being advantageous for their potential application in nanodevices.

Low-temperature growth and photoluminescence property of ZnS nanoribbons.

At a low temperature of 450 degrees C, ZnS nanoribbons have been synthesized on Si and KCl substrates by a simple chemical vapor deposition (CVD) method with a two-temperature-zone furnace. Zinc and sulfur powders are used as sources in the different temperature zones. X-ray diffraction (XRD), selected area electron diffraction (SEAD), and transmission electron microscopy (TEM) analysis show that the ZnS nanoribbons are the wurtzite structure, and there are two types-single-crystal and bicrystal nanoribbons. Photoluminescence (PL) spectrum shows that the spectrum mainly includes two parts: a purple emission band centering at about 390 nm and a blue emission band centering at about 445 nm with a weak green shoulder around 510 nm.