Copper sheet with grain size of 30-60μm was processed by plastic deformation of asymmetrical accumulative rolling-bonding（AARB）with the strain of 3.2.The effects of annealing temperature and time on ...microstructural evolution were studied by means of electron backscattered diffraction（EBSD）.EBSD grain mapping,recrystallization pole figure and grain boundary misorientation angle distribution graph were constructed,and the characteristics were assessed by microstructure,grain size,grain boundary misorientation and texture.The results show that ultra fine grains（UFG）are obtained after annealing at 250℃ for 30？40 min.When the annealing is controlled at 250℃for 40 min,the recrystallization is finished,a large number of small grains appear and most grain boundaries consist of low-angle boundaries.The character of texture is rolling texture after the recrystallization treatment,but the strength of the texture is faint.While second recrystallization happens,{110}〈1ī2〉＋{112}〈11ī〉 texture component disappears and turns into{122}〈212〉cube twin texture component.
Ancrod, a serine protease purified from the venom of
Agkistrodon rhodostoma
, is highly specific for fibrinogen. It causes anticoagulation by defibrinogenation and has been used as a therapeutic ...anticoagulant for the treatment of moderate to severe forms of peripheral arterial circulatory disorders in a variety of countries. The DNA of ancrod was amplified by recursive PCR with a yeast bias codon and cloned into the pGEM-T Easy vector. In order to achieve a high level secretion and a full activity expression of ancrod in
Pichia pastoris
(
P. pastoris
), the
P. pastoris
protein disulfide bond isomerase (
Pp
PDI) was co-overexpressed in the strain. The secretion characteristics of ancrod with and without
Pp
PDI were examined. With co-overexpression of
Pp
PDI, the production of recombinant ancrod (rAncrod) was increased to 315 mg/L in the culture medium, which is twofold higher than the control strain carrying only the ancrod gene. Through purified by Ni
2+
affinity chromatography and phenyl Sepharose column, the purity of rAncrod was found to be as high as 95.2%. The fibrinogenolytic and zymographic activities of the rAncrod were determined and found to be similar to that of the native protein. This improved expression system can facilitate further studies and the industrial production of ancrod.
MicroRNAs (miRNAs) (noncoding RNAs of 20–25 nucleotides) play important roles in the post-transcriptional regulation of gene expression in various eukaryotes and prokaryotes. Piwi-interacting RNAs ...function by combining with PIWI proteins to regulate protein synthesis and to stabilize mRNA, the chromatin framework, and genome structure. This study investigates the role of miRNAs in regeneration. A scrDNA library was constructed, and 17 noncoding RNAs from
Eisenia fetida
(an optimal model for the study of earthworm regeneration) were cloned and characterized. In addition, reverse transcription polymerase chain reaction was performed to analyze the expression of four small RNAs during different developmental stages. The expression levels of these RNAs in regenerating tissue were higher than in normal tissue, and the expression patterns of these small RNAs were unique during development.
Biosynthesis offers opportunities for cost-effective and sustainable production of semiconductor quantum dots (QDs), but is currently restricted by poor controllability on the synthesis process, ...resulting from limited knowledge on the assembly mechanisms and the lack of effective control strategies. In this work, we provide molecular-level insights into the formation mechanism of biogenic QDs (Bio-QDs) and its connection with the cellular substrate metabolism in Escherichia coli. Strengthening the substrate metabolism for producing more reducing power was found to stimulate the production of several reduced thiol-containing proteins (including glutaredoxin and thioredoxin) that play key roles in Bio-QDs assembly. This effectively diverted the transformation route of the selenium (Se) and cadmium (Cd) metabolic from Cd
(PO
)
formation to CdS
Se
QDs assembly, yielding fine-sized (2.0 ± 0.4 nm), high-quality Bio-QDs with quantum yield (5.2%) and fluorescence lifetime (99.19 ns) far exceeding the existing counterparts. The underlying mechanisms of Bio-QDs crystallization and development were elucidated by density functional theory calculations and molecular dynamics simulation. The resulting Bio-QDs were successfully used for bioimaging of cancer cells and tumor tissue of mice without extra modification. Our work provides fundamental knowledge on the Bio-QDs assembly mechanisms and proposes an effective, facile regulation strategy, which may inspire advances in controlled synthesis and practical applications of Bio-QDs as well as other bionanomaterials.
The disproportionation reaction of Mn3+ ions induced by the Jahn–Teller effect hinders the practical application of Mn-based oxides in aqueous zinc-ion batteries (AZIBs). Herein, Ag2Mn8O16 is ...reported as a promising cathode for AZIBs, and its performance improvement mechanism in a chlorine-containing electrolyte is comprehensively investigated. As demonstrated, the partial deintercalation of silver ions promotes the valence state and reactivity of the Mn element in Ag2–x Mn8O16 and favors the formation of the AgCl layer. As an electronic insulator and ionic conductor, the AgCl layer can effectively inhibit the manganese dissolution, reduce the activation energy barrier, and facilitate the zinc diffusion kinetics in Ag2Mn8O16. As expected, the Ag2Mn8O16 cathode exhibits high capacity of 369.2 mAh g–1 at 0.1 A g–1 and 269.6 mAh g–1 after 200 cycles at 0.5 A g–1 in the optimized chlorine-containing electrolyte, implying the in situ interface engineering can eliminate the dilemma of dissolution and inactivation of Mn-based oxides in aqueous batteries.
Quantum dots (QDs) are recognized as the excellent fluorescence and photochemical materials to be applied in bioimaging, biomedical, and solar cell fields. Biosynthesized QDs (bio-QDs) have attracted ...attention due to their simple, eco-friendly, and excellent biocompatible traits. Moreover, bio-QDs could not be replaced by chemically fabricated QDs in many fields. Bio-QDs synthesized by different microorganisms have diverse characteristics. In this work, the biosynthesis of QDs by Tetrahymena pyriformis, a typical protozoa in aquatic environments, was achieved for the first time. The synthesized materials by T. pyriformis emitted yellow fluorescence and had an average diameter of 8.27 ± 0.77 nm. Spectral characterization results demonstrated that the synthesized QDs were CdS
Se
. Meanwhile, the fluorescence intensities of the synthesized bio-QDs showed a linear relationship with Cd
dosage ranging from 20 to 80 μM. The fluorescence enhancement of the synthesized QDs was highly selective to Cd
compared to other metal ions. The bio-QDs were demonstrated to have a great potential to be applied for Cd
detection. This work provides valuable information about the transformation of heavy metal ions in protozoan and is useful to accelerate the applications of the synthesized QDs.
BACKGROUND： Combined hepatectomy and radiofrequency ablation（RFA） provides an additional treatment for patients with Barcelona Clinic Liver Cancer（BCLC） stage B hepatocellular carcinoma（HCC） who are ...conventionally deemed unresectable. This study aimed to analyze the outcome of this combination therapy by comparing it with transarterial chemoembolization（TACE）. METHODS： We retrospectively reviewed 51 patients with unresectable BCLC stage B HCC who had received the combination therapy. We compared the survival of these patients with that of 102 patients in the TACE group（control）. Prognostic factors associated with worse survival in the combination group were analyzed.RESULTS： No differences in tumor status and liver function were observed between the TACE group and combination group. The median survival time for the combination group and TACE group was 38（6-54） and 17（3-48） months, respectively（P〈0.001）. The combination group required longer hospitalization than the TACE group 8（5-14） days vs 4（2-9） days,P〈0.001. More than two ablations decreased the survival rate in the combination group. CONCLUSIONS： Combined hepatectomy and RFA yielded a better long-term outcome than TACE in patients with unresectable BCLC stage B HCC. Patients with a limited ablated size（≤2 cm）, a limited number of ablations（≤2）, and adequate surgical margin should be considered candidates for combination therapy.
Background： Although human parainfluenza virus （HPIV） has been determined as an important viral cause of acute respiratory infections （ARIs） in infants and young children, data on long-term ...investigation are still lacking to disclose the infection pattern of HPIV in China. Methods： Nasopharyngeal aspirates were collected from 25,773 hospitalized pediatric patients with ARIs from January 2004 through December 2012 for respiratory virus screen by direct immuno-fluorescence assay. Results： Out of these specimens, 1675 （6.50%, 1675/25,773） showed HPIV positive, including 261 （1.01%, 261/25,773） for HPIVI, 28 （0.11%, 28/25,773） for HPIV2, and 1388 （5.39%, 1388/25373） for HPIV3, 2 of the samples were positive for both HPIV1 and HPIV3, and 36 were co-detected with other viruses. The positive rates of HPIVs were higher in those younger than 3 years old. HPIV3 was detected from all age groups, predominantly from patients under 3 years of age, and the highest frequency was found in those 6 months to 1-year old （352/4077, 8.63%）. HPlV3 was the dominant type in each of the years detected between May and July. HPIV1 showed a peak in every odd year, mainly in August or September. HPIV was detected most frequently from patients with upper respiratory infection （12.49%, 157/1257）, followed by bronchitis （ 11.13%, 176/2479）, asthma （9.31%, 43/462）, bronchiolitis （5.91%, 150/2536）, pneumonia （6.06%, 1034/17,068）, and those with underlying diseases （1.0%, 15/1506）. HPIV3 is the dominant type in these six disease groups referred above, especially in the asthma group. Conclusions： HPIV is one of the important viral causes of ARIs in infants and young children in Beijing based on the data from the hospitalized children covering a 9-year term. HPIV3 is the predominant type in all these years and in most of the disease groups. HPIVs with different types show different seasonality.
PDF