Photo-Induced Self-assembly of Copolymer-Capped Nanoparticles into Colloidal Molecules.

Colloidal molecules (CMs) are precisely defined assemblies of nanoparticles (NPs) that mimic the structure of real molecules, but externally programming the precise self-assembly of CMs is still challenging. In this work, we show that the photo-induced self-assembly of complementary copolymer-capped binary NPs can be precisely controlled to form clustered ABx or linear (AB)y CMs at high yield (x is the coordination number of NP-Bs, and y is the repeating unit number of AB clusters). Under UV light irradiation, photolabile p-methoxyphenacyl groups of copolymers on NP-A*s are converted to carboxyl groups (NP-A), which react with tertiary amines of copolymers on NP-B to trigger the directional NP bonding. The x value of ABx can be precisely controlled between 1 and 3 by varying the irradiation duration and hence the amount of carboxyl groups generated on NP-As. Moreover, when NP-A* and NP-B are irradiated after mixing, the assembly process generates AB clusters or linear (AB)y structures with alternating sequence of the binary NPs. This assembly approach offers a simple yet non-invasive way to externally regulate the formation of various CMs on demand without the need of redesigning the surface chemistry of NPs for use in drug delivery, diagnostics, optoelectronics, and plasmonic devices.

Structural Characteristics and Phylogenetic Analysis of the Mitochondrial Genomes of Four Krisna Species (Hemiptera: Cicadellidae: Iassinae).

Krisna species are insects that have piercing-sucking mouthparts and belong to the Krisnini tribe in the Iassinae subfamily of leafhoppers in the Cicadellidae family. In this study, we sequenced and compared the mitochondrial genomes (mitogenomes) of four Krisna species. The results showed that all four mitogenomes were composed of cyclic double-stranded molecules and contained 13 protein-coding genes (PCGs) and 22 and 2 genes coding for tRNAs and rRNAs, respectively. Those mitogenomes exhibited similar base composition, gene size, and codon usage patterns for the protein-coding genes. The analysis of the nonsynonymous substitution rate (Ka)/synonymous substitution rate (Ks) showed that evolution occurred the fastest in ND4 and the slowest in COI. 13 PCGs that underwent purification selection were suitable for studying phylogenetic relationships within Krisna. ND2, ND6, and ATP6 had highly variable nucleotide diversity, whereas COI and ND1 exhibited the lowest diversity. Genes or gene regions with high nucleotide diversity can provide potential marker candidates for population genetics and species delimitation in Krisna. Analyses of parity and neutral plots showed that both natural selection and mutation pressure affected the codon usage bias. In the phylogenetic analysis, all subfamilies were restored to a monophyletic group; the Krisnini tribe is monophyletic, and the Krisna genus is paraphyletic. Our study provides novel insights into the significance of the background nucleotide composition and codon usage patterns in the CDSs of the 13 mitochondrial PCGs of the Krisna genome, which could enable the identification of a different gene organization and may be used for accurate phylogenetic analysis of Krisna species.

Hydrothermal Synthesis of Co3O4/ZnO Hybrid Nanoparticles for Triethylamine Detection.

Development of high performances gas sensors to monitor and detect the volatile organic compound triethylamine is of paramount importance for health and environmental protection. The Co3O4-ZnO nanoparticles composite was successfully synthesized by the one-step hydrothermal route and annealing process in this work. The gas sensitivity test results show that the composite exhibits excellent triethylamine-sensing performance at a cobalt content of 1 at%, indicating potential application for triethylamine detection. The sensor based on the Co3O4-ZnO composite had higher sensitivity to triethylamine, better selectivity, and faster response recovery rate compared with pure ZnO sensor. Combined with the structural characteristics of the characterized Co3O4-ZnO nanocomposite, the optimized triethylamine sensing performances can be ascribed to the p-n heterojunction effect between Co3O4 and ZnO, as well as the catalytic and high oxygen adsorption properties of Co3O4.

Emission Properties of Diblock Copolymers Composed of Poly(ethylene glycol) and Dense 1,2,3-Triazole Blocks.

This article describes a new block copolymer (EGm-b-APn, where m and n denote the degrees of polymerization) of poly(ethylene glycol) (PEG) and poly(1,4-(1-H-1,2,3-triazolylene)methylene) prepared by copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization of 3-azido-1-propyne (AP) in the presence of PEG carrying a propargyl moiety. The EGm-b-APn samples are well soluble in polar organic solvents. Unexpectedly, we observed that solutions of EGm-b-APn in N,N-dimethylformamide emitted fluorescence. We systematically studied absorption and emission properties of the block copolymers. The experimental data have exhibited that APn block is an intrinsic fluorophore. Interestingly, the emission of EGm-b-APn can be easily tuned from ultraviolet to green fluorescence by changing the excitation wavelength. This enables fine-tuning of its optical property without the need of changing the chromophore. Moreover, the block copolymers show a fluorescence response to metal ions (e.g., Cu2+). Our discoveries contribute to the fundamental understanding of the optical properties of dense triazole-based polymer and raise intriguing prospects for fabricating novel emissive triazole-based materials.

[Follow-up study on diet, folic acid and iron status in 358 cases of Uighur pregnant women from Xinjiang Kashi].

OBJECTIVE: To understand the dietary intake situation of Uighur pregnant women, investigate folic acid level and its influencing factors, to provide evidence for health education of maternal nutrition and implementation of proper nutrition, balanceddiet guidance. METHODS: 358 cases of Uighur trimester pregnant women for the study, took the method of 3 d 24 h dietary recall to survey their dietary and collect blood samples. The Hb was detected by the cyanide methemoglobinmethod. The content of folic acid was determined by a double antibody biotin sandwich enzyme-linked immunosorbent assay( ELISA) method. The data processing used V2. 7. 13 nutrition calculator software, and compare with "DRIs"in 2013. RESULTS: Diet composition and nutrient intake: Grains, livestock, poultry, fats and oils intake almost reached the standards, vegetables, fruits, eggs, milk and beans intake were below standards, the intake of fish and shrimp were( 0. 18 ± 3. 95) g, high salt intake( 9. 03 ± 3. 97). In early pregnancy, energy( 101. 19%), protein( 107. 87%), calcium( 32. 48%), iron( 195. 30%), zinc( 106. 63%), selenium( 55. 77%), iodine( 15. 54%), vitamin B1( 87. 50%) vitamin B2( 60. 00%), vitamin C( 65. 69%), folic acid( 13. 21%). The late pregnant energy( 84. 29%), protein( 72. 44%), calcium( 27. 77%), iron( 180. 38%), zinc( 121. 16%), selenium( 53. 11%), iodine( 11. 26%), vitamin B1( 75. 33%), vitamin B2( 49. 33%), vitamin C( 57. 37%), folic acid( 13. 15%). The total detection rate of anemia in pregnant women was 18. 89%, mean of Hb was( 119. 42 ± 13. 90) g/L. Comparison of Hb levels( P < 0. 05) and anemia detection rate( P < 0. 05) in the early and late pregnant women, the difference was significant; total lack of folic acid detection rate was 75. 42%, the average folate levels( 9. 15 ± 4. 22) nmol/L, compare folate levels( P < 0. 05) and folate deficiency detection rate( P < 0. 05) in early and late pregnant women, the difference was significant. CONCLUSION: The dietary structure of pregnant women is less irrational. The intake of fruits and vegetables are inadequate and the intake of fish and shrimp is serious lack. The intake of salt is high. The proportion of three heat nutrients are in a suitable ratio range. The energy and protein intake are below the DRIs in the late pregnant, iron and zinc intake are high. The selenium, vitamin B2 and C intake are inadequate, a serious lack of calcium, iodine and folic acid in whole pregnancy. The anemia in late pregnant is more serious than early pregnant, during pregnancy folate level is low and late pregnant is lower than early.

Synthesis and properties study of the uniform nonspherical styrene/methacrylic acid copolymer latex particles.

A facile method to prepare the nonspherical amphiphilic random copolymer of poly(styrene-co-methacrylic acid) (poly(St-co-PMAA)) latex particles with well-defined shapes and high yields by one-step batch emulsifier-free polymerization was demonstrated. In our strategy, only varying the molar ratio of styrene (St) to methacrylic acid (MAA), no seed-particles, no cross-linker, and no multistep control procedures were needed. Due to the presence of carboxyl groups on the surface of (poly(St-co-PMAA) latex particles, these latex particles can be used as templates for fabricating core-shell nonspherical functional materials, such as poly(St-co-PMAA)@SiO2 and poly(St-co-PMAA)@polypyrrole). The corresponding nonspherical hollow structures (SiO2 and polypyrrole) could be obtained after removal of the templates. In addition, poly(St-co-PMAA) latex particles exhibit interesting morphologies in ethanol.

Simultaneous synthesis and assembly of silver nanoparticles to three-demensional superstructures for sensitive surface-enhanced Raman spectroscopy detection.

Construction of superstructures with controllable morphologies from NPs is of great scientific and technological importance. A one-step method for simultaneous synthesis and assembly of Ag NPs to three-dimensional (3D) nanoporous superstructures is demonstrated. By varying the adsorption time of Ag precursors, an array of well-defined Ag superstructures with different morphologies are harvested. A "hot spot"-rich substrate for surface-enhanced Raman spectroscopy is established, which exhibits high sensitivity in trace detection of molecules. It is believed that the presented 3D nanoporous Ag superstructures hold great potential for various uses, such as novel multifunctional sensing and monitoring chips or devices.