A novel heteroseneous reaction for generating gaseous nitrous acid

The short-lived reactive specimen nitrous acid HONO was generated in the gas phase by the heterogeneous reaction of gaseous HCl with AgNO2 which can generate higher concentration of HONO than other methods. We investigated the process from generation to dissociation in the gas phase under different controlled temperatures, and discussed the ionization and reaction on the solid surface by combination of the photoelectron spectroscopy and photoionization mass spectroscopy （PES-PIMS） and in situ diffuse reflectance infrared Fourier transform spectroscopy （DRIFTS）.     

Modified fiber qualities of the transgenic cotton expressing a silkworm fibroin gene

A silkworm gene for fibroin was introduced into the upland cotton WC line by Agrobacterium-mediated transformation. PCR detection for fibroin, nptII and gus genes, Kanamycin (Km)-resistance analysis and GUS-histochemical assay were conducted on 30 regenerated plants from 9 callus lines, and 17 positive plants were obtained by these 5 screening methods. By Km-resistance analysis and PCR for fibroin, 6 homozygous lines in T₃ were obtained. Southern blot and Northern bolt demonstrated that the fibroin gene was inserted into the genome of these 6 lines, stably inherited and expressed. Compared to the control, the surface structure of mature fiber in the 6 lines was significantly distorted and an increased number of convolution was observed by scanning electron microscopy (SEM). Fiber quality traits analysis indicated that fiber elongation of the 6 homozygous lines was all increased and fiber strength of 3 lines was enhanced. These results indicated that fibroin expression influenced cotton fiber structure and quality, suggesting that fibroin has great potential for improving cotton fiber quality by genetic engineering. Supported by National High Technology Research and Development Program of China (Grant No. 2006AA100105), Science & Technology Pillar Program of Jiangsu Province (Grant No. BE2008310) and Programme of Introducing Talents of Discipline to Universities (Grant No. B08025) Contributed equally to this work     

An exceptionally well-preserved fossil Kalligrammatid from the Jehol Biota

A new species of Neuroptera, Sophogramma lii sp. nov. is described and illustrated in this paper. This new species is assigned to Sophogramma Ren of Kalligrammatidae, mainly based on its humeral recurrent veins, the basal cell present between posterior branch of media at base of wing, etc. The new species is distinguished from all other Sophogramma species on the difference of wing venation. This exceptionally well-preserved specimen is recovered from the Yixian Formation, Huangbanjigou, located near Beipiao City, in western Liaoning Province. The genus diagnosis has been emended based on new characters shown in this new species. Based on a summary of localities, distribution and geological ages of all genera and species of the Kalligrammatidae, we suggest that Kalligrammatids might have originated in Eastern Asia, especially in China. Function of the wing pigmentation is discussed briefly. Supported by National Natural Science Foundation of China (Grant Nos. 30430100 and 40872022), Beijing Natural Science Foundation Program (Grant No. 5082002), Scientific Research Key Program (Grant No. KZ200910028005) and PHR Project of of Beijing Municipal Commission of Education, Science-Technology Basic Condition Platform from the Ministry of Science and Technology of the People’s Republic of China (Grant No. 2005DKA21402)     

TiO2-based building materials: Above and beyond traditional applications

In the 1910s, TiO₂ began to be used in building materials as pigments and opacifier due to its excellent optical property. Since the photocatalytic property of TiO₂ was observed in 1972, its application field was expanded to air cleaning and sterilization. Thereafter, people added TiO₂ into building materials to develop novel and facile building materials. These materials were widely used for air cleaning, sterilization, self-cleaning, anti-fogging, decoration, and building cooling. The combination of building and other functions can serve simultaneously. Although TiO₂-based building materials have bright prospects, some aspects such as improving the stability and enhancing photoactive performance of the materials are of importance for future research. Supported by the National High Technology Research and Development Program (“863” Program) of China (Grant No. 2007AA061402), Chinese Key Technology Research and Development Program of the Eleventh Five-year Plan (Grant No. 2006BAJ02A08), Hangzhou Science & Technology Development Program (Grant No. 20061133B27) and Research Fund for the Doctoral Program of Higher Education (Grant No. 20070335197)     

Engineering <Emphasis Type="Italic">Deinococcus radiodurans</Emphasis> into biosensor to monitor radioactivity and genotoxicity in environment

Based on a genetically modified radioresistant bacteria Deinococcus radiodurans, we constructed a real time whole cell biosensor to monitor radioactivity and genotoxicity in highly radioactive environment. The enhanced green fluorescence protein （eGFP） was fused to the promoter of the crucial DNA damage-inducible recA gene from D. radiodurans, and the consequent DNA fragment （PrecA-egfp） carried by plasmid was introduced into D. radiodurans R1 strain to obtain the biosensor strain DRG300. This engineered strain can express eGFP protein and generate fluorescence in induction of the recA gene promoter. Based on the correlation between fluorescence intensity and protein expression level in live D. radiodurans cells, we discovered that the fluorescence induction of strain DRG300 responds in a remarkable dose-dependent manner when treated with DNA damage sources such as gamma radiation and mitomycin C. It is encouraging to find the widely detective range and high sensitivity of this reconstructed strain comparing with other whole cell biosensors in former reports. These results suggest that the strain DRG300 is a potential whole cell biosensor to construct a detective system to monitor the biological hazards of radioactive and toxic pollutants in environment in real time.     

Temperature-sensitive gold-nanotube array membranes modified with poly（N-isopropylacrylamide）

A kind of temperature-sensitive nanotube array membrane was developed by modifying gold-nanotube array membranes with poly（N-isopropylacrylamide） （PNIPAm）. The permeation ability of the mem-branes at different temperatures was investigated using sodium fluorescein and quantum dots as probes. The results showed that the pore diameter of nanotube was changed due to the reversible response of PNIPAm-modified membranes to temperature, and then the permeation ability of the mem-branes was changed. The permeation of fluorescence probes was slow and even almost blocked at 25℃ （below the lower critical solution temperature, LCST）, since PNIPAm formed expanded structures and decreased the pore size. While at 40℃ （above the LCST）, the permeation was increased, since PNIPAm became compact structures and the pore diameter was increased. Furthermore, the permeation ability of the temperature-sensitive nanotube array membranes could be adjusted reversibly and it is possible to use the membranes in nanofluidic devices, nanogates, etc.     

Combining docking and comparative molecular similarity indices analysis （COMSIA） to predict estrogen activity and probe molecular mechanisms of estrogen activity for estrogen compounds

Estrogen compounds are suspected of disrupting endocrine functions by mimicking natural hormones, and such compounds may pose a serious threat to the health of humans and wildlife. Close attention has been paid to the prediction and molecular mechanisms of estrogen activity for estrogen com- pounds. In this article, estrogen receptor a subtype （ERa） -based comparative molecular similarity indices analysis （COMSIA） was performed on 44 estrogen compounds with structural diversity to find out the structural relationship with the activity and to predict the activity. The model with the significant correlation and the best predictive power （R^2= 0.965, Q^2 LOO： 0.599, R^2 pred ： 0.825） was achieved. The COMSIA and docking results revealed the structural features for estrogen activity and key amino acid residues in binding pocket, and provided an insight into the interaction between the ligands and these amino acid residues.     

Three-dimensional observation of the phase structure of high density polyethylene （HDPE）/poly（ethyleneco-butene） （PEB） blend by laser scanning confocal microscopy

In this paper,high density polyethylene (HDPE)/poly(ethylene-co-butene) (PEB) blend (50/50 wt%) was prepared through solution blending and then compression molding,and subsequently examined by laser scanning confocal microscopy (LSCM). The PEB used in this experiment was labeled with a small quantity of a fluorescein derivative to render fluorescence. The initial films showed uniform dye dis-tribution and no indication of phase separation within the resolution of optical microscopy. Sample films annealing at 140℃ followed by rapid cooling to room temperature showed obvious phase sepa-ration and bicontinuous structure. The present work indicates that by labeling one component with fluorescein derivative,LSCM can efficiently perform in situ depth profiling of polymer blends.     

Evolution of the serum resistance-associated SRA gene in African trypanosomes

Serum resistance-associated (SRA) protein, a protein unique for Trypanosoma brucei rhodesiense, is responsible for resistance of this parasite to the lysis by normal human serum (NHS) and is a vital molecular marker to distinguish this species from other African trypanosomes. We cloned and sequenced the SRA basic copy (SRAbc) gene from T. b. rhodesiense and related species and found that this gene is confined to the subgenus Trypanozoon. The average 82% identity among the sequenced SRAbc genes indicates that they may have a common origin and are highly conserved. Since SRAbc coexists in the T. b. rhodesiense genome with SRA, we propose that SRAbc might be the ‘donor VSG’, which after duplication became inserted into the expression site by recombination. Under natural selection, SRAbc could reform into SRA following mosaic formation. Supported by National Natural Science Foundation of China (Grant Nos. 30570245, 30670275), Changjiang Scholars and Innovative Research Team in University (Grant No. DPCKSCU/IRT0447), International Foundation for Science of Sweden (Grant No. B/4318-1), Grant Agency of the Czech Republic (Grant No. Z60220518) and Education Foundation of the Czech Republic (Grant No. 2B06129)     

Genetic analysis and gene mapping of a narrow leaf mutant in rice ( Oryza sativa L.)

A narrow leaf mutant was obtained after T-DNA transformation conducted on a rice variety Zhonghua 11. Several abnormal morphological characteristics, including semi-dwarf, delayed flowering time, narrow and inward rolling leaves, and lower seed-setting, were observed. The rate of net photosynthesis (under saturate light) of flag leaves in the mutant was significantly lower than that of the wild type. Moreover, the leaf transpiration rate and stomatal conductance in the mutant flag leaf were lower than those of the wild type at the grain filling stage. It was found that the mutant phenotype was not caused by the T-DNA insertion. Genetic analysis showed that the mutant was controlled by a single recessive gene, designated as nal3(t). A genetic linkage map was constructed using a large F₂ mapping population derived from a cross between nal3(t) and an indica variety Longtefu B with 6 polymorphic markers on chromosome 12 identified from 366 SSR markers by the BAS method. Gene nal3(t) was mapped between the markers RM7018 and RM3331. Fine mapping of nal3(t) locus was conducted with 22 newly developed STS markers based on the sequence diversity around the region harboring nal3(t) between Nipponbare and 93–11, and nal3(t) was finally mapped to a 136-kb region between the STS markers NS10 and RH12-8. Supported by National High Technology Research and Development Program of China (863 Program) (Grant No. 2006AA10A102), National Natural Science Foundation of China (Grant No. 30600349) and Natural Science Foundation of Zhejiang Province (Grant No. Y306149)     

Functional characterization and mapping of two MADS box genes from peach （Prunus persica）

Previously an AGAMOUS gene homologue PpMADS4 and a FRUITFULL gene homologue PpMADS6 were isolated from peach （Prunus persica）, and both genes were shown to express in the developing floral and fruits. To gain insight into their function, the two genes were constitutively expressed in Arabidopsis thaliana and their effects on plant growth and floral organ development were studied in this work. The transgenic plants all displayed early flowering and conversion of inflorescence to floral meristem. However, the two genes had different effects on the floral organ structures in A. thaliana. The transgenic plants overexpressing PpMADS4 displayed homeotic conversion of floral organs, and particularly the perianth abscission was inhibited. The plants overexpressing PpMADS6 showed early flowering, produced higher number of carpels, petals, and stamens than nontransgenic plants, and pod shatter was prevented; significantly, the transgenic plants yielded more than one siliques from a single flower. A SSR molecular marker was developed for PpMADS4, and it was then assigned into the G5 linkage group of Prunus sp. Both PpMADS4 and PpMADS6 genes were located at the same region in the G5 linkage group. Our results showed the potential application of these two MADS box genes for crop and fruit tree improvement.     

Fabrication of the 19-filament Fe/Cu clad MgB2 wire via in situ powder-in-tube method

Using commercial amorphous B powder (92% in purity) and Mg powder (99% in purity) as starting materials, 19-filament Fe/Cu clad MgB2 wires were fabricated by an in situ powder-in-tube method. Heat treatment was performed at 700℃ for 1 h under an argon gas atmosphere. The influence of Mg/B ratio on the microstructure and superconducting properties of the wires was investigated. It was found that the major phases of MgB2 wires were MgB2 accompanied with relatively small amounts of MgO and Fe2B impurities. With 5% excess Mg addition, the onset TC slightly decreased. However, the transport JC at 4.2 K and 4 T reached 1.07×104 A·cm-2, increasing by a factor of 1.4 compared to the stoichiometric sample. Moreover, the Mg1.05B2 sample showed an improved field dependence of JC, suggesting that less voids and smaller grain size of the Mg1.05B2 core lead to better grain connectivity and stronger flux pinning.     

Structural dependences of the <Emphasis Type="Italic">η</Emphasis><Superscript>6</Superscript> complexes of 3-amino-9-ethylcarbazole with chromium tricarbonyl fragment on third-order optical nonlinearities

Degenerate four-wave mixing measurements, using the 35 ps pulses at 532 nm, have been employed to investigate the third-order nonlinear optical parameters of two chromium tricarbonyl complexes η6-bonded to 3-amino-9-ethylcarbazole at either the NH2-substituted aryl ring （1） or the unsubstituted ring （2） and their precursor 3-amino-9-ethylcarbazole （AECz）. The second-order hyperpolarizability y of the compounds 1 and 2 were found to be 42.9×10^-31 and 35.9×10^-31 esu, respectively, approximately one order of magnitude greater than AECz. The relation between the molecular structure and second-order hyperpolarizability of the compounds I and 2 was explored in detail based on the three-level model and the density functional theory （DFT） calculation. The theoretical results indicate that the spatial distribution of electron density has the profound role in the third-order nonlinear optical properties.     

Molecular identification and phylosenetic position of Cuora yunnanensis

The Yunnan box turtle （Cuora yunnanensis, Boulenger, 1906）, which has drawn much attention in conservation biology, was regarded as extinct since it was previously known only from 12 specimens collected in Yunnan, China, before 1908. Recently, live specimens have been discovered which are suggested to be C. yunnanensis. To determine whether the newly discovered specimens are really C. yunnanensis, we have established a molecular phylogeny, with a 1725-bp fragment of mitochondrial DNA, using samples from three live individuals of C. yunnanensis, together with sequence data from a museum specimen of C. yunnanensis （MNHN 1907.10） and other members of the genus Cuora. We found that the three newly discovered individuals and the old museum specimen of C. yunnanensis are very similar both in morphology and in mitochondrial DNA sequence, suggesting that the three new individuals are the very C. yunnanensis, and thus the species is not extinct. Our phylogenetic analysis also demonstrates that C. yunnanensis is not of recent hybrid origin, but rather represents a distinct evolutionary lineage.     

Synthesis and self-assembly of amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments

A novel amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments was successfully synthesized via the atom transfer radical polymerization （ATRP） technique, using a bromo-terminated difunctional polysulfone as macroinitiator. The difunctional polysulfone macroinitiator was prepared by esterifying the phenolic end groups of polysulfone to aaloesters. This macroinitiator was then used to initiate the polymerization of a glucose-carrying monomer, 3-O-methacryloyl-1,2：5,6-di-O-isopropylidene-D-glucofuranose （MAIpG）, resulting an ABA type triblock copolymer. After acidolysis treatment, the isopropylidenyl groups of the protected sugar residues were removed, thus the amphiphilic ABA type triblock copolymer with well-defined glycopolymer segments was obtained. The polymers obtained were identified by FT-IR, ^1H-NMR, GPC, and TGA. The self-assembly behavior of the amphiphilic glycopolymer in selective solvent （e.g. DMF/H2O） system was also preliminarily explored. The resultant amphiphilic glycopolymer shows potential applications in the fields of controlled release and delivery of drugs, micro-reactors, nano-materials, medical devices, and SO on.     

Mineral magnetic properties of surface sediments at Bei’anhe, Beijing, and its environmental significance

A multiparameter investigation of surface sediments from the Bei＇anhe section （Beijing） has been conducted using environmental magnetic approaches. The studied sedimentary sequence consists of pluvial and lacustrine silts and clay of the Holocene age. Magnetite, hematite and pyrrhotite were identiffed as the dominant magnetic minerals. The mineral magnetic characteristics are considered to reflect the Holocene paleoenvironmental processes of the studied area, which are different from the mineral magnetic properties of typical polluted sections reported in the Beijing area. The low-field magnetic susceptibility and saturated isothermal remanence magnetization of the section decrease gradually with increasing depth. This indicates that the concentration of magnetic minerals in the strata decreases down the section. Values of interparametric ratios, such as ARM/SIRM, XARM/Xand SIRM/X, gradually increase with increasing depth, which indicates a down-section decreasing trend in the magnetic grain size of the sediments. Pyrrhotite occurs below the depth of 22 cm, suggesting the existence of redox interface. The magnetic variations of the Bei＇anhe surface sediments might be controlled by two geological processes： reductive diagenesis and pedogenesis. Our findings may have provided a reference point for magnetic investigation of polluted surface sediments in the Beijing area.     

Bayesian mixed models and divergence time estimation of Chinese cavefishes （Cyprinidae： Sinocyclocheilus）

The genus Sinocyclocheilus is distributed in Yun-Gui Plateau and its surrounding region only, within more than 10 cave species showing different degrees of degeneration of eyes and pigmentaUon with wonderful adaptations. To present, published morphological and molecular phylogenetic hypotheses of Slnocyclocheilus from prior works are very different and the relationships within the genus are still far from clear. We obtained the sequences of cytochrome b （cyt b） and NADH dehydrogenase subunlt 4 （ND4） of 34 species within Sinocyclocheilus, which represent the most dense taxon sampling to date. We performed Bayesian mixed models analyses with this data set. Under this phylogenetic framework, we estimated the divergence times of recovered clades using different methods under relaxed molecular clock. Our phyloegentic results supported the monophyly of Sinocyclocheilus and showed that this genus could be subdivided into 6 major clades. In addition, an earlier finding demonstrating the polyphyletlc of cave species and the most basal position of S. jii was corroborated. Relaxed divergence-time estimation suggested that Sinocyclocheilus originated at the late Miocene, about 11 million years ago （Ma）, which is older than what have been assumed.