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Covering a broad optical spectrum, ternary InxGa1−xAs nanowires, grown by bottom-up methods, have been receiving increasing attention due to the tunability of the bandgap via In composition modulation. However, inadequate knowledge about the correlation between growth and properties restricts our ability to take advantage of this phenomenon for optoelectronic applications. Here, three different InGaAs nanowires were grown under different experimental conditions and atom probe tomography was used to quantify their composition, allowing the direct observation of the nanowire composition associated with the different growth conditions.
In this paper, a tri-band bandpass filter (BPF) using asymmetric stub-loaded stepped-impedance resonator (SL-SIR) is presented. The asymmetric characteristic of SL-SIR broadens degrees of freedom for three controllable modes design. Also, the coupling coefficients (Mij) and the external quality factors (Qei) at each passband of the filter can be independently adjusted by the proposed mixed-type feedline structure. Besides, multi-transmission zeros are produced to improve the isolation and selectivity of the passbands. Finally, a tri-band BPF is operated at 1.9 GHz (time division long term evolution – TD-LTE band), 3.2 GHz (worldwide interoperability for microwave access – WiMAX band), and 5.8 GHz (wireless local area networks – WLAN band) and their insertion loss are 1.03, 0.94, and 1.27 dB, respectively. The measured results of the fabricated tri-band BPF exhibit good agreement with simulated results.
Forty-five tree rings (1881–1925) were taken from a white spruce grown near Campbell River in Mackenzie Delta, Canada, for the measurement of 14C activity variation. Because of the narrowness of the rings, 2 and sometimes 3 rings were combined to yield a total of 21 specimens. The 14C content in these specimens was measured with a liquid scintillation-PM tube counter system of the History Department of Peking University. The data points exhibit a 10‰ variation, anti-correlated with sunspot numbers. The physical implication is discussed.
We measured the Δ14C values in 57 rings (from AD 1824 to 1880) of a white spruce grown in Mackenzie Delta (68°N, 130°W), as part of our continuing study of the Δ14C variation related to solar activities. The values exhibit a 10‰ fluctuation with an 11-year periodicity anti-correlated with the solar activity cycle. We also measured the Δ14C values in 6 rings (from AD 1940 to 1945). The abnormally high value in the 1943 ring may be due to two large solar flares occurring in 1942.
Radio-astronomical observations of the annular eclipse of 1958 April 19 (η = re/r⊙ = 0.939, ϕ = 18°14′34″.08, λ = −7h18m 01s.86) were especially interesting since this year was, apparently, the year of maximum solar activity. Some preliminary results of the observations carried out by a joint expedition of the Soviet and Chinese Academies of Sciences, equipped with seven radio telescopes, are described in this report.
Schistosoma japonicum, a human blood fluke, causes a parasitic disease affecting millions of people in Asia. Thioredoxin–glutathione system of S. japonicum plays a critical role in maintaining the redox balance in parasite, which is a potential target for development of novel antischistosomal agents. Here we cloned the gene of S. japonicum thioredoxin (SjTrx), expressed and purified the recombinant SjTrx in Escherichia coli. Functional assay shows that SjTrx catalyses the dithiothreitol (DTT) reduction of insulin disulphide bonds. The coupling assay of SjTrx with its endogenous reductase, thioredoxin glutathione reductase from S. japonicum (SjTGR), supports its biological function to maintain the redox homeostasis in the cell. Furthermore, the crystal structure of SjTrx in the oxidized state was determined at 2·0 Å resolution, revealing a typical architecture of thioredoxin fold. The structural information of SjTrx provides us important clues for understanding the maintenance function of redox homeostasis in S. japonicum and pathogenesis of this chronic disease.
There have been inconsistent results published regarding the relationship between dyslipidaemia and an increased risk of colorectal neoplasia (CRN), including colorectal adenoma (CRA) and colorectal cancer (CRC). We conducted a meta-analysis to explore the relationship between dyslipidaemia and CRN.
We identified studies by performing a literature search using PubMed, EMBASE and the Science Citation Index through October 2013.
We analysed thirty-three independent studies reporting the association between CRN and at least one of the selected lipid components, including total cholesterol (TC), TAG, HDL-cholesterol (HDL-C) and LDL-cholesterol (LDL-C).
CRN cases (n 21 809) were identified.
Overall, people with high levels of serum TAG (risk ratio (RR)=1·08; 95 % CI 1·05, 1·12, P<0·00001) and LDL-C (RR=1·07; 95 % CI 1·00, 1·14, P=0·04) presented an increased prevalence of CRN. Subgroup analyses revealed that high levels of serum TC (RR=1·04; 95 % CI 1·01, 1·09, P=0·02), TAG (RR=1·06; 95 % CI 1·03, 1·10, P=0·0009) and LDL-C (RR=1·11; 95 % CI 1·04, 1·19, P=0·003) increased the risk of CRA but not of CRC. No association between serum HDL-C and risk for CRN (including CRA and CRC) was observed.
Both TAG and LDL-C were significantly associated with an increasing prevalence of CRN. High levels of serum TC, TAG and LDL-C were positively associated with CRA but not with CRC. No significant association was observed between levels of serum HDL-C and CRN.
The bioavailability of dietary ionised calcium is affected by intestinal basic environment. Calcium-binding peptides can form complexes with calcium to improve its absorption and bioavailability. The aim of this study was focused on isolation and characterisation of a calcium-binding peptide from whey protein hydrolysates. Whey protein was hydrolysed using Flavourzyme and Protamex with substrate to enzyme ratio of 25 : 1 (w/w) at 49 °C for 7 h. The calcium-binding peptide was isolated by DEAE anion-exchange chromatography, Sephadex G-25 gel filtration and reversed phase high-performance liquid chromatography (RP-HPLC). A purified peptide of molecular mass 204 Da with strong calcium binding ability was identified on chromatography/electrospray ionisation (LC/ESI) tandem mass spectrum to be Glu-Gly (EG) after analysis and alignment in database. The calcium binding capacity of EG reached 67·81 μg/mg, and the amount increased by 95% compared with whey protein hydrolysate complex. The UV and infrared spectrometer analysis demonstrated that the principal sites of calcium-binding corresponded to the carboxyl groups and carbonyl groups of glutamic acid. In addition, the amino group and peptide amino are also the related groups in the interaction between EG and calcium ion. Meanwhile, the sequestered calcium percentage experiment has proved that EG-Ca is significantly more stable than CaCl2 in human gastrointestinal tract in vitro. The findings suggest that the purified dipeptide has the potential to be used as ion-binding ingredient in dietary supplements.
Nanoerythrocyte-shaped ytterbium orthovanadate (YbVO4) with substantially uniform size have been successfully synthesized by a simple and facile trisodium citrate-assisted hydrothermal method. The erythrocyte-shaped YbVO4 nanocrystals with self-assembled spherical and biconcave structure have a diameter of ∼500 nm, which were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, high-resolution transmission electron microscopy and photoluminescence. The luminescent properties of erbium ion-doped ytterbium orthovanadate nanocrystals with different morphologies by different complexing agents were different in the relative intensity under identical measurement conditions, which exhibited the interesting morphology-dependent optical properties. The different energy transfer mechanisms and photoluminescence intensities might be the result of the greatly reduced defect centers.
Single-crystalline rock-salt PbS nanowires (NWs) were synthesized using three different routes; the solvothermal, chemical vapor transport, and gas-phase substitution reaction of pre-grown CdS NWs. They were uniformly grown with the  or ,  direction in a controlled manner. In the solvothermal growth, the oriented attachment of the octylamine (OA) ligands enables the NWs to be produced with a controlled morphology and growth direction. As the concentration of OA increases, the growth direction evolves from the  to the higher surface-energy  and  directions. In the synthesis involving chemical vapor transport and the substitution reaction, the use of a lower growth temperature causes the higher surface-energy growth direction to change from  to . We fabricated field effect transistors using single PbS NW, which showed intrinsic p-type semiconductor characteristics for all three routes. For the PbS NW with a thinner oxide layer, the carrier mobility was measured to be as high as 10 cm2V−1s−1.
We begin by reviewing the major results dealing with the structure of the cl-degrees, and then focus on the method of the Yu–Ding Theorem, which is an important result in this area. By strengthening the Yu–Ding procedure, we construct a cl-cuppable cl-degree of c.e. sets.
Activation tagging plays an important role in plant genomics studies. In this paper, an activation tagging library containing 50 000 Basta-resistant lines was constructed by mediated transformation of the mutant bzr1-D of Aribidopsis thaliana. Among these transformants, 47 lines showed obvious phenotypes, including late flowering time, dwarf growth habit, changed leaf shape, longer leaf petiole, leaves lacking trichomes, sterility and no kink between stem/leaf. Some T-DNA flanking sequences were obtained by TAIL (thermal asymmetric interlaced) and nested PCR. Results showed that the mutants contained one to three T-DNA insertions. The insertions were distributed in the first, fourth and fifth chromosomes of the genome.
Intergeneric transfer of plasmid vectors pSET152 and pHL212 from donor Escherichia coli ET12567/pUZ8002 and S17-1 to Streptomyces cinnamonensis was demonstrated and optimized. Assisted by this conjugation system, nsdA gene disruption was achieved through PCR-targeted gene replacement. One AprRKanS exconjugant BIB309 was then isolated and confirmed to be the nsdA null mutant. Compared with the starting strain, monensin production by the nsdA− mutant BIB309 increased 270% in vitro.
A real-time fluorescent polymerase chain reaction (PCR) assay was established to detect Streptococcus suis serotype 2. Primers and Taqman probe were designed according to cps2I (capsular polysaccharide 2I) gene using bio-software Primer Express2.0 and Oligo6.0. An 81 bp DNA fragment was amplified from S. suis serotype 2 genomic DNA, and the PCR product was cloned into pMD18-T vector and confirmed by DNA sequencing. The real-time fluorescent PCR amplification curve on a Lightcycler® showed that the method is accurate and specific for S. suis serotype 2 amplification, whereas reference bacteria S. suis, Escherichia coli, Salmonella sp., Staphylococcus aureus, Shigella sp., Listeria monocytogenes strains and a blank control were all negative. Tenfold serial dilutions of S. suis serotype 2 were used to measure the sensitivity of real-time fluorescent PCR: ten copies of bacteria could be detected in one PCR reaction and only 30 min were required for a single test. To examine the stability of the real-time fluorescent PCR, the positive control was detected at two different times. The threshold cycle (Ct) values showed no statistical differences (P>0.05). Thus, this method was stable and repeatable. These results indicate that this real-time fluorescent PCR technique could be applied for epidemic supervision in entry–exit inspection and quarantine.
In order to investigate the molecular mechanism of rehydration after serious drought in broomcorn millet (Panicum miliaceum L.), a forward subtracted cDNA library was constructed between normal watered leaves and rehydrated leaves after serious drought conditions, using the suppressive subtraction hybridization (SSH) technique. A total of 60 positive clones were picked out at random from the subtracted library and sequenced, and redundancy sequences were removed after sequence alignment. Based on the results of sequence homologous comparison and function querying, 32 expressed sequence tags (EST) were highly homologous with known ESTs. Most of those sequences were related to either abiotic or biotic stress in plants. Of those sequences, 11 ESTs were homologous with ESTs in rat (Rattus norvegicus) liver after partial hepatectomy. The Blast result of proteins revealed that 28 ESTs were similar to known proteins. The functions of these proteins mainly involve signal transduction, transcription and protein processing. This experiment demonstrated that a range of specific genes was induced and expressed in broomcorn millet during the rehydration stage after serious drought.
By using a Reynolds-averaged two-dimensional computation of a turbulent
an airfoil at post-stall angles of attack, we show that the massively separated
disordered unsteady flow can be effectively controlled by periodic blowing–suction
near the leading edge with low-level power input. This unsteady forcing
the evolution of the separated shear layer to promote the formation of
lifting vortices, which in turn interact with trailing-edge vortices in
manner and thereby alter the global deep-stall flow field. In a certain
range of post-stall
angles of attack and forcing frequencies, the unforced random separated
become periodic or quasi-periodic, associated with a significant lift enhancement.
opens a promising possibility for flight beyond the static stall to a much
of attack. The same local control also leads, in some situations, to a
reduction of drag.
On a part of the airfoil the pressure fluctuation is suppressed as well,
be beneficial for high-α buffet control. The computations are in
with several recent post-stall flow control experiments. The physical mechanisms
responsible for post-stall flow control, as observed from the numerical
explored in terms of nonlinear mode competition and resonance, as well
dynamics. The leading-edge shear layer and vortex shedding from the trailing
are two basic constituents of unsteady post-stall flow and its control.
Since the former
has a rich spectrum of response to various disturbances, in a quite wide
natural frequency of both constituents can shift and lock-in to the forcing
or its harmonics. Thus, most of the separated flow becomes resonant, associated
much more organized flow patterns. During this nonlinear process the coalescence
of small vortices from the disturbed leading-edge shear layer is enhanced,
stronger entrainment and hence a stronger lifting vortex. Meanwhile, the
trailing-edge vortex is pushed downstream. The wake pattern also has a
change: the shed vortices of alternate signs tend to be aligned, forming
a train of
close vortex couples with stronger downwash, rather than a Kármán
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