Large-Scale, Mechanically Robust, Solvent-Resistant, and Antioxidant MXene-Based Composites for Reliable Long-Term Infrared Stealth.

MXene-based thermal camouflage materials have gained increasing attention due to their low emissivity, however, the poor anti-oxidation restricts their potential applications under complex environments. Various modification methods and strategies, e.g., the addition of antioxidant molecules and fillers have been developed to overcome this, but the realization of long-term, reliable thermal camouflage using MXene network (coating) with excellent comprehensive performance remains a great challenge. Here, a MXene-based hybrid network comodified with hyaluronic acid (HA) and hyperbranched polysiloxane (HSi) molecules is designed and fabricated. Notably, the presence of appreciated HA molecules restricts the oxidation of MXene sheets without altering infrared stealth performance, superior to other water-soluble polymers; while the HSi molecules can act as efficient cross-linking agents to generate strong interactions between MXene sheets and HA molecules. The optimized MXene/HA/HSi composites exhibit excellent mechanical flexibility (folded into crane structure), good water/solvent resistance, and long-term stable thermal camouflage capability (with low infrared emissivity of ≈0.29). The long-term thermal camouflage reliability (≈8 months) under various outdoor weathers and the scalable coating capability of the MXene-coated textile enable them to disguise the IR signal of various targets in complex environments, indicating the great promise of achieved material for thermal camouflage, IR stealth, and counter surveillance.

Hydrosilylation Adducts to Produce Wide-Temperature Flexible Polysiloxane Aerogel under Ambient Temperature and Pressure Drying.

Despite incorporation of organic groups into silica-based aerogels to enhance their mechanical flexibility, the wide temperature reliability of the modified silicone aerogel is inevitably degraded. Therefore, facile synthesis of soft silicone aerogels with wide-temperature stability remains challenging. Herein, novel silicone aerogels containing a high content of Si are reported by using polydimethylvinylsiloxane (PDMVS), a hydrosilylation adduct with water-repellent groups, as a "flexible chain segment" embedded within the aerogel network. The poly(2-dimethoxymethylsilyl)ethylmethylvinylsiloxane (PDEMSEMVS) aerogel is fabricated through a cost-effective ambient temperature/pressure drying process. The optimized aerogel exhibits exceptional performance, such as ultra-low density (50 mg cm-3), wide-temperature mechanical flexibility, and super-hydrophobicity, in comparison to the previous polysiloxane aerogels. A significant reduction in the density of these aerogels is achieved while maintaining a high crosslinking density by synthesizing gel networks with well-defined macromolecules through hydrolytic polycondensation crosslinking of PDEMSEMVS. Notably, the pore/nanoparticle size of aerogels can be fine-tuned by optimizing the gel solvent type. The as-prepared silicone aerogels demonstrate selective absorption, efficient oil-water separation, and excellent thermal insulation properties, showing promising applications in oil/water separation and thermal protection.

[Effects of different tillage methods on tea garden soil physical characteristics and tea yield].

The effects of three tillage methods, i.e., no tillage, rotary tillage, deep tillage, on tea garden soil compaction, soil moisture, soil bulk density, yield component factors and tea yield were studied through field experiments in Langxi Country of Anhui Province. The results indicated that the effects of three tillage methods on soil bulk density and soil compaction were in order of deep tillage>rotary tillage>no tillage. Deep tillage and rotary tillage could effectively break the argillic horizon layer and decrease the soil compaction. Compared with no tillage, soil compaction and soil bulk density (0-30 cm) under deep tillage decreased 16.4% and 13.4%-27.5%, respectively. Deep tillage could significantly increase soil water storage space and enhance the water holding capacity of the soil. Compared with no tillage, the soil moisture of 15-30 cm soil layer was increased by 7.7% under deep tillage. The different tillage methods had little effect on soil porosity. Rotary tillage and deep tillage could increase soil specific surface area and the ratios of soil gas and soil liquid. The diurnal changes of photosynthetic rate and transpiration rate of tea both exhibited double-peak pattern. There was a significant midday depression caused principally by stomatal factors. Under deep tillage, the tea leaf transpiration rate decreased, shoot density increased, 100-bud dry mass and water use efficiency increased significantly, and the tea yield increased by 17.6% and 6.8% compared with no tillage and rotary tillage, respectively. Deep tillage was the most appropriate tillage practice in tea garden of east Anhui Province.

[Soil pH buffer capacity of tea garden with different planting years].

In order to investigate the effects of long-term tea planting on soil pH buffer capacity (pHBC), the variation of pHBC and its influence factors were investigated in tea gardens of 10, 15, 20, 25 and 30 years in Langxi and Qimen of Anhui Province. The results showed that the acid-base titration method was suitable for the determination of soil pHBC of tea gardens. The amount of acid-base added had approximate linear relationship with soil pH value in specific section (pH 4.0-6.0) of acid-base titration curves, so the soil pHBC could be calculated by linear regression equation. Soil pHBC in the tea gardens from the two regions showed a downward trend with increasing the planting years, which decreased at rates of 0.10 and 0.06 mmol · kg(-1) · a(-1) in Langxi and Qimen tea gardens, respectively. Soil pHBC had significant positive correlation with CEC, soil organic matter, base saturation and physical clay content, and significant negative correlation with exchangeable acid and exchange H+.

Identification of genes to differentiate closely related Salmonella lineages.

BACKGROUND: Salmonella are important human and animal pathogens. Though highly related, the Salmonella lineages may be strictly adapted to different hosts or cause different diseases, from mild local illness like gastroenteritis to fatal systemic infections like typhoid. Therefore, rapid and accurate identification of Salmonella is essential for timely and correct diagnosis of Salmonella infections. The current identification methods such as 16S rRNA sequencing and multilocus sequence typing are expensive and time consuming. Additionally, these methods often do not have sufficient distinguishing resolution among the Salmonella lineages. METHODOLOGIES/PRINCIPAL FINDINGS: We compared 27 completely sequenced Salmonella genomes to identify possible genomic features that could be used for differentiation of individual lineages. We concatenated 2372 core genes in each of the 27 genomes and constructed a neighbor-joining tree. On the tree, strains of each serotype were clustered tightly together and different serotypes were unambiguously separated with clear genetic distances, demonstrating systematic genomic divergence among the Salmonella lineages. We made detailed comparisons among the 27 genomes and identified distinct sets of genomic differences, including nucleotide variations and genomic islands (GIs), among the Salmonella lineages. Two core genes STM4261 and entF together could unambiguously distinguish all Salmonella lineages compared in this study. Additionally, strains of a lineage have a common set of GIs and closely related lineages have similar sets of GIs. CONCLUSIONS: Salmonella lineages have accumulated distinct sets of mutations and laterally acquired DNA (e.g., GIs) in evolution. Two genes entF and STM4261 have diverged sufficiently among the Salmonella lineages to be used for their differentiation. Further investigation of the distinct sets of mutations and GIs will lead to novel insights into genomic evolution of Salmonella and greatly facilitate the elucidation of pathogeneses of Salmonella infections.

Effects of flow rate and substrate concentration on the formation and H2 production of photosynthetic bacterial biofilms.

Photosynthetic bacteria (PSB), Rhodopseudomonas palustris CQK 01, were immobilized on the surface of a thin glass slide in a lab-scale flat panel photobioreactor under different flow rates and substrate concentrations. The morphology, dry weight and thickness of the mature PSB biofilms were determined to reveal the relationship between biofilm formation and hydrogen production performance. The mature biofilm formed at a low flow rate and a high substrate concentration showed a looser structure, these structures of the mature biofilm then affected the H(2) production performance of the bioreactor during mature stage. The biofilm formed at a flow rate of 228 ml/h and a substrate concentration of 60 mmol/l exhibited the highest dry weight and optimally porous structure, which is beneficial not only for hydrogen removal from the biofilm but also glucose diffusion into the biofilm, thus significantly boosting the photo-hydrogen production performance.

[Imaging diagnosis of synovial tuberculosis of sheath of wrist].

OBJECTIVE: To investigate the imaging features of synovial tuberculosis of sheath of wrist. METHODS: Three patients of synovial tuberculosis of sheath of wrist underwent surgical operation from Oct. 2002 to Oct. 2009 included 2 males and 1 female, the age of 48, 67, 76 years respectivly. X-rays of 3 patients, CTs of 2 patients and MRI of 1 patient were retrospectively analyzed and the relevant literature were reviewed. RESULTS: There were 3 cases with the soft tissue mass in the palm side of wrist, the section was unclear. There were no osteoporosis and no changes of bone destruction. There was 1 case with the punctate calcification in the soft tissue. MRI showed the embedded cystic mass of flexor tendon and "8" shape in carpal tunnel pressure, and showed abnormal signal (T1 low-signal, T2 slightly higher signal), a small part of the internal point showed high signal. CT showed the synovial membrane were obvious thickening and enhanced, corpus liberum in tendon sheath were no obvious strengthening. CONCLUSION: Synovial tuberculosis of sheath of wrist has certain characteristics on radiographic image. The MRI has more clinical value than X-ray and CT.

Formation and hydrogen production of photosynthetic bacterial biofilm under various illumination conditions.

The application of immobilized-cell technology in photobioreactor for hydrogen production could offer improvements in photo-hydrogen production rate and light utilization efficiency. Indigenous Rhodopseudomonas palustris CQK 01 was attached to the surface of a cover glass slide in a flat-panel photobioreactor, to form biofilm under illumination with a range of intensities and wavelengths. The morphology and structure of mature photosynthetic bacterial (PSB) biofilm were determined to elucidate the relationship between biofilm formation and hydrogen production performance. The effects of operation conditions on hydrogen production performance of the biofilms formed under various illumination conditions were experimentally investigated. The results showed that illumination wavelength and intensity substantially influenced the morphology and structure of the biofilm, and the hydrogen production performance of mature biofilm varied significantly with the illumination conditions that were used for biofilm formation. Biofilm formed under 590 nm and 5000 lx illumination showed the highest hydrogen production performance.

[Comparison of the relativity of MRI appearance of cartilage injuries and postoperative effect of arthroscope on articular cartilage disease of knee].

OBJECTIVE: To analyze the indication of arthroscope by examining the correlations between cartilage injury degree confirmed by MRI and postoperative effect. METHODS: From Aug. 2005 to April 2008, 87 cases with knee osteoarthritis were treated by arthroscopes including 44 males and 43 females,aged from 16 to 67 years (means 46.3 years). Arthrodial cartilage of knee was graded by ICRS MR, and the therapeutic effect was evaluated by Lysholm scoring. RESULTS: All 87 knees of 87 cases were followed-up for from 12 to 30 months (averaged 23 months). The cartilage injury degree of knees was graded as follows: grade 4 in 30 cases, grade 3 in 23 cases, grade 2 in 20 cases, grade 1 in 12 cases, grade 0 in 2 cases, means grade (2.770 +/- 1.138). Postoperative Lysholm score was from 59 to 100, means (95.170 +/- 7.556). Coefficient correlation (r) = -0.152, P = 0.159 > 0.05. Although the results had no correlations between cartilage injury degree and Lysholm score, negative correlation tendency existed. CONCLUSION: The patients with higher grade of knee cartilage injury degree confirmed by MRI (1.5T) have worse effect after operation, the grade is not a gold standard as a operation indication in arthroscopic procedure.

Serum brain natriuretic peptide in children with Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is a common cause of acquired heart disease in children. Recent studies have focused on the biochemical markers of the myocardium, their high sensitivity and specificity and significance in the diagnosis of KD. This study aimed to determine the serum level of brain natriuretic peptide (BNP) and its relation with the heart function of children with KD and to explore its clinical value in diagnosis of KD. METHODS: Forty-three KD children, aged from 5 months to 8 years (mean 2.3±0.6 years), were admitted to Qingdao Children's Hospital from February 2007 to April 2009. Among them 27 were male, and 16 female. The 43 patients served as a KD group. Patients with myocarditis, cardiomyopathy, congenital heart disease and other primary heart diseases were excluded. Thirty healthy children, aged from 3 months to 15 years (mean 2.5±0.8 years) or 17 males and 13 females served as a control group. There were no significant differences in age and gender between the two groups (P>0.05). In the KD group, ELISA was used to measure the levels of serum BNP in acute and convalescent stages; and in the control group, the levels of serum BNP were measured once randomly. Left ventricular ejection fraction (LVEF), left ventricular shorten fraction (LVSF), cardiac index (CI) and left ventricular inflow velocity through the mitral annulus (including E-velocity and A-velocity) were measured by two-dimensional echocardiography in the acute and convalescent stages in the KD group. All data were expressed as mean±SD. The methods of analysis included Student's t test and the linear regression analysis test. P<0.05 was considered statistically significant. RESULTS: The level of serum BNP in the acute stage (517.26±213.40) ng/ml was significantly higher than that in the convalescent stage (91.56±47.97) ng/ml in the control group (37.55±7.56) ng/ml (P<0.01). The levels of LVEF, LVSF and CI in the acute stage were significantly lower than those in the convalescent stage (P<0.05), but the E/A level was not significantly different between the acute and convalescent stages (P>0.05). Linear regression analysis showed that the BNP level was negatively correlated with the levels of LVEF, LVSF and CI(r=-0.63, -0.52, -0.53, P<0.05), but not significantly correlated with the E/A level (r=-0.18, P>0.05). CONCLUSION: The levels of serum BNP are significantly increased in KD patients, and are negatively correlated with the levels of LVEF, LVSF, and CI. The detection of serum BNP level is of clinical significance in the diagnosis of KD.

[Study on the correlation between knee osteoarthritis imaging and effects of arthroscope].

OBJECTIVE: To explore the indications of arthroscope for the treatment of knee osteoarthritis and investigate the correlation between knee osteoarthritis imaging and effects of arthroscope. METHODS: From 2005.8 to 2008.4, 86 patients with knee osteoarthritis underwent arthroscope examination and treatment. Among the patients, 44 patients were male, and 42 patients were female, ranging in age from 46 to 67 years, averaged 56.3 years. Arthrodial cartilage of knee was graded by ICRS MR, and by Kellgern Laqrence X-ray. All the patients were followed up, and the duration ranged from 12 to 30 months. The Lysholm score was evaluated at the follow-up time. RESULTS: Among 86 knees in 86 cases, cartilage injury degree of knees was graded as follows: grade 4 in 30 cases, grade 3 in 22 cases, grade 2 in 20 cases, grade 1 in 12 cases, grade 0 in 2 cases, mean grade (2.77 +/- 1.138). Postoperative Lysholm score ranged from 59 to 100, averaged (95.17 +/- 7.556), Kendall's correlation coefficient was -0.089, P = 0.317. There was no correlations between cartilage injury degree and Lysholm score. X-ray of knees was graded as follows: grade 4 in 0 cases, grade 3 in 24 cases, grade 2 in 38 cases, grade 1 in 17 cases, grade 0 in 7 cases, mean grade was (2.13 +/- 0.67), the Kendall's correlation coefficient was -0.851 with negative correlations (P = 0.036) between postoperative Lysholm score and K/L grade. CONCLUSION: There is no correlation between the grade of knee cartilage injury confirmed by MRI (1.5T) and effects of arthroscopy, and the grade is not a gold standard as an operation indication in arthroscope procedure. The K/L grade in X-ray had important effects.

Salmonella expressing a T-cell epitope from Sendai virus are able to induce anti-infection immunity.

Bacterial fimbriae can accept foreign peptides and display them on the cell surface. A highly efficient gene replacement method was used to generate peptide vaccines based on Salmonella enterica subsp. enterica serovar Typhimurium LT2. DNA encoding an epitope from Sendai virus, SV9 (Sendai virus nucleoprotein peptide 324-332, FAPGNYPAL), which is known to induce cytotoxic T lymphocytes, was incorporated into the gene encoding AgfA (the major subunit protein of thin aggregative fimbriae of Salmonella) by replacing an equal length DNA segment. To improve cytotoxic T lymphocyte recognition, both termini of the peptide were flanked by double alanine (AA) or arginine (RR) residues. Western blotting and immunofluorescence microscopy using AgfA-specific antiserum verified the expression of chimeric AgfA; expression was also proved by a Congo red binding assay. Oral immunizations of C57BL/6 mice with the four strains induced an epitope-specific T-cell response (detected by enzyme-linked immunosorbent spot assay). When the mice were challenged with the Sendai virus, the magnitude of the infection was significantly reduced in the immunized groups compared with the controls. The Salmonella fimbrial display system efficiently induces a cellular immune response and anti-infection immunity in vivo, providing a new strategy for the development of efficient peptide vaccination.

[Comparison on mitochondrial ATP6, ATP8 and Cyt b genes between Chinese Tibetans in three different zones: detecting the signature of natural selection on mitochondrial genome].

Mitochondrial DNA (mtDNA) differs from nuclear genome in many aspects such as lack of recombination, thus the investigation of mtDNA plays an essential role in human evolutionary history. We compared different sequences (approximately 2 kb) of ATP6, ATP8 and Cyt b genes in mtDNA among Tibetans in three different zones and found that the whole mtDNA sequences of the three genes, ATP6 and ATP 8 genes deviate gradually from neutral model with the increase of altitudes, yet no differences were observed. Also we found that the effect of purifying selection on Cyt b gene was elevated with the decrease of altitudes. Meanwhile, there was a possibility for the adaptive selection in ATP6 gene, which had an enhanced trend with the increase of altitudes. Thus, the geographic environment is the main determinant for selection, namely, different geographic environment has direct effect on selection.

[Comparative analysis of the complete mitochondrial genome between Tibetan and Han population].

OBJECTIVE: To construct the haplogroup and perform an analysis of mitochondrial whole-genome sequence in Tibetan and Han Chinese. Variations of nucleotide of mitochondrial DNA (mtDNA) were identified and compared between the Tibetan and Han population. METHODS: The mtDNA whole sequences of 40 Tibetan and 50 Han individuals were sequenced by an Applied Biosystems 3730 DNA automatic sequencer. The sequences were assembled using software phredPhrap16.0, and all assembled sequences were manually verified according to the criterion of rCRS (revised Cambridge Reference Sequence). The haplogroups of mtDNA were constructed using phylogenetic analysis according to the criteria of MITOMAP by Network method. The data were elucidated by integrated methods. RESULTS: Authors' results showed that all the pooled 90 subjects belonged to the Macrohaplogroup M and N, and were classified into 13 haplogroups. No differences were observed among the haplogroups of the two populations except for M9 haplogroup. A total of 21 variants were detected by comparing the mtDNA whole sequences between Tibetan and Han population; of those, 5 variants have not been reported before. In addition, we constructed the haplotypes of 5 variants harboring the D-loop region, and founded prominent difference in both supertype 1 and supertype 2 between Tibetan and Han population. CONCLUSION: The phylogenetic analysis indicates that the Tibetan and Han ethnic groups shared close maternal relationship in origin. The biological implication of the significant variants is worth elucidating; whether they are the results of adaptive selection or neutral selection or pathological variations need to be further studied.

Two oral HBx vaccines delivered by live attenuated Salmonella: both eliciting effective anti-tumor immunity.

Live attenuated bacteria have great potential for use in vaccine development due to several unique advantages, including stable antigen expression, effective antigen presentation, convenient and inexpensive delivery, and low cost of vaccine production. In this study, we expressed hepatitis B virus x gene (HBx) on mouse melanoma cells as the target antigen and constructed Salmonella-based HBx vaccines by two strategies, i.e., recombinant eukaryotic plasmid encoding HBx and a recombinant prokaryotic plasmid encoding Type III secretion system effector-HBx fusion protein. Both HBx constructs elicited significant levels of CTL reaction and IFN-gamma secreting T cells. When mice were challenged with melanoma cells expressing HBx, tumor growth rates in immunized animals were significantly slower than controls. Tumor sizes and tumor weight indices of immunized mice were also significantly lower than controls. We conclude that both strategies described in this study may lead to novel approaches of tumor vaccines.