Search

The photon-counting detector (PCD) based spectral computed tomography attracts much more attentions since it has the capability to provide more accurate identification and quantitative analysis for biomedical materials. The limited number of photons within narrow energy-bin leads to low signal-noise ratio data. The existing supervised deep reconstruction networks for CT reconstruction are difficult to address these challenges. In this paper, we propose an iterative deep reconstruction network to synergize model and data priors into a unified framework, named as Spectral2Spectral. Our Spectral2Spectral employs an unsupervised deep training strategy to obtain high-quality images from noisy data with an end-to-end fashion. The structural similarity prior within image-spectral domain is refined as a regularization term to further constrain the network training. The weights of neural network are automatically updated to capture image features and structures with iterative process. Three large-scale preclinical datasets experiments demonstrate that the Spectral2spectral reconstruct better image quality than other state-of-the-art methods.

Objective To identify the key pathways and potential biomarkers with diagnotic value for the development of intrahepatic cholangiocarcinoma (ICC) by integrating bioinformatics analysis. Methods We downloaded 3 high-quality datasets of ICC gene microarray (GSE26566, GSE32879 and GSE45001) from Gene Expression Omnibus (GEO) and the high-throughput sequencing data of cholangiocarcinoma (CCA) from the Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were screened using the Limma package in R software; Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were performed with Cluster Profiler package. Protein-protein interaction (PPI) network analysis of DEGs was subsequently carried out using the Search Tool for the Retrieval of Interacting Genes (STRING) database and subsequently visualized with Cytoscape. In addition, the transcriptional expression of hub genes was further verified by Gene Expression Profiling Interactive Analysis (GEPIA), and their diagnostic value was assessed by receiver operating characteristic (ROC) curve. Finally, the methylation level of the hub genes was determined using Diseasemeth 2.0. Results In total, 382 DEGs were screened and validated, including 90 up-regulated and 292 down-regulated genes. The up-regulated genes were noticeably enriched in PI3K-Akt signaling pathway, while the down-regulated in the carbon metabolism pathway. A PPI network was constructed with 289 nodes, and 6 hub genes were identified by PPI analysis: PRSS23, LGALS1, VCAN, COL5A1, ITGB1 and EHHADH. ROC curve results showed that all the hub genes distinguished tumor tissues from non-tumorous tissues. Conclusion Six hub genes are identified by integrative bioinformatics analysis, which may be potential molecular biomarkers for early diagnosis of ICC.

BiFeO3(BFO)/Sr2Bi4Ti5O18(SBT) bilayer composite thin films were prepared using the sol-gel method. The influence of the SBT transition layer thickness on the properties of BFO/SBT bilayer composite thin films was studied. The results showed that an SBT transition layer with the proper thickness can improve the BFO/SBT bilayer composite film performance. X-ray diffraction (XRD) analysis revealed that a bismuth layered perovskite structure is formed in all of the thin films. The scanning electron microscopy (SEM) result showed that the BFO/80 nmSBT sample exhibits good crystallization, an improved density and a uniform minimum grain size compared with the other samples. The X-ray photoelectron spectroscopy (XPS) result showed that the Fe2+ content and oxygen vacancy concentration are lowest in the BFO/80 nm SBT sample. This sample has good ferroelectric properties: the leakage current density has the lowest value of J = 5.21 × 10-5 A/cm2 among the samples at 350 kV/cm, 2Ec = 900 kV/cm, and 2Pr = 151 μC/cm2. At a low electric field (E 100 kV/cm). The relative dielectric constant (er) is 121, the dielectric loss (tanδ) is 0.024 at 105 Hz.

The Sr2Bi4Ti5O18 (SBT-5) ferroelectric thin films were prepared on Pt/Ti/SiO2/Si substrate using the sol-gel method and annealing in oxygen, air, and nitrogen. Their properties were measured. After annealing in oxygen, the films showed good crystallization and a larger average grain size of approximately 34.05 nm. XPS analysis clearly showed that annealing in oxygen inhibited the generation of oxygen vacancies in the films, which contributed to the melioration of the ferroelectric properties. The remanent polarization was 20.09 μC/cm2 and the coercive field was 75 kV/cm. When the electric field was 15 kV/cm, the leakage current density was approximately 3.88 × 10−7A/cm2, while the Ohmic conduction was the dominating leakage mechanism. Because the content of the oxygen vacancy in the samples annealed in oxygen atmosphere was lower, the fixing effect on the domain structure was weaker and the volume effect was not obvious, so the aging degree of the samples was low. The larger relative dielectric constant was 742, while the dielectric loss was 0.037 when the test frequency was 2.0 × 105 Hz.

Aerospace vehicle containing aeronautics and astronautics function realizes completely reusable, which is the key weapon for the future world countries to fight for air and space control power. However, the current nose cone of aerospace plane cannot respond optimally to the changes in the external environment. The constant structure of nose cone also greatly reduces the range of motion and flexibility. In this paper, a biomimetic skeleton structure of morphing nose cone inspired by variable geometry mechanism of honeybee abdomen is designed, which can achieve stretching and bending continuously. Based on the screw theory, the degree of freedom of morphing nose cone is calculated. Then a prototype of biomimetic skeleton structure with six segments for the morphing nose cone has been manufactured. Further, the simulation analysis and experimental test of the morphing nose cone are conducted respectively to evaluate the deformation ability and dynamic performance. The results show that deformation ability of the morphing nose cone meets the design requirements. The flexibility of drive mechanism in the morphing nose cone causes high-frequency components, which greatly reduces its dynamic performance. This research provides the way to develop a theoretical analysis and experimental support for the design of morphing nose cone for aerospace vehicle.

Composite cathodes have attracted great attention due to the integrated advantages of each pure structure. Also, the component ratio deserves a careful modulation to further improve the correspondi...

This study examined the effect of Ca doping on the properties of Sr2Bi4Ti5O18 (SBTi) ferroelectric thin films. According to the results of the study, the performance of SBTi thin films are improved by suitable Ca doping. It can be seen from XRD analysis, all of the thin films formed a bismuth layered perovskite structure without other impure phases. SEM shows that the sample with a doping content of 10 mol% has good crystallization, uniform grain size and good film density. Compared with the characteristics of other films, the thin film sample with 10 mol% Ca shows high crystallinity, the lowest Ti3+ content, the lowest oxygen vacancy concentration, and with the large remanent polarization 2Pr = 33.5 μC/cm2, the double coercive field 2Ec = 182.8 kV/cm; furthermore, the leakage current density is 1.67 × 10−7 A/cm2. The film sample doped with 10 mol% Ca also displays better dielectric properties, with a larger dielectric constant (er = 795) and lower dielectric loss (tanδ = 0.03) when the test frequency is 105 Hz. The dielectric tunability T = 18.6% at 200 kV/cm and 500 kHz.

Accurate identification of ECG signals is the key to intelligent diagnosis of ECG monitoring systems. In order to improve the classification accuracy of ECG signals, an improved ECG signal classification algorithm based on BP neural network was studied. Firstly, statistical analysis was performed on the MIT-BIH Arrhythmia Database sample experts. The normal heart beat, ventricular premature beat, left bundle branch block heart beat and right bundle branch block heart beat were selected as neural network recognition targets, and extracted by principal component analysis. 25 heart beat features are used as sample vectors. The simulation results show that the improved BP neural network has better classification and recognition ability, and the accuracy of the whole sample classification is 98.4%. The algorithm has fast convergence speed and high classification accuracy, which is helpful for detecting and diagnosing heart diseases.

Continuous cropping negatively affects soil fertility, physicochemical properties and the microbial community structure. However, the effects of long-term chili monoculture on the dominant microbial community assembly are not known. In this study, the impact of long-term chili monoculture on the correlation between the dominant microbial community and soil environmental variables was assessed. The results indicated that increasing duration of chili monoculture generated significant changes in soil nutrients, soil aggregates and soil enzymes: nutrient contents increased overall, mechanically stable macroaggregates increased and microaggregates decreased, water-stable macroaggregates and microaggregates decreased, β-glucosidase decreased nonlinearly, and nitrate reductase and alkaline phosphatase activities showed a nonlinear increase. Moreover, an increasing number of years of chili monoculture also affected the structure of the dominant microbiota, with substantial changes in the relative abundances of 11 bacterial and fungal genera. The drivers of the dominant microbial community assembly in rhizosphere soil were soil moisture, abiotic nitrogen, pH and salt., Graphical Abstract Long-term chili monoculture alters environmental variables affecting the dominant microbial community in rhizosphere soil.

Additional file 1.

It is difficult to assess and monitor the spinal cord injury (SCI) because of its pathophysiology after injury, with different degrees of prognosis and various treatment methods, including laminectomy, durotomy, and myelotomy. Medical communication services with different factors such as time of surgical intervention, procedure choice, spinal cord perfusion pressure (SCPP), and intraspinal pressure (ISP) contribute a significant role in improving neurological outcomes. This review aims to show the benefits of communication services and factors such as ISP, SCPP, and surgical intervention time in order to achieve positive long-term outcomes after an appropriate treatment method in SCI patients. The SCPP was found between 90 and 100 mmHg for the best outcome, MAP was found between 110 and 130 mmHg, and mean ISP is ≤20 mmHg after injury. Laminectomy alone cannot reduce the pressure between the dura and swollen cord. Durotomy and duroplasty considered as treatment choices after severe traumatic spinal cord injury (TSCI).

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p

Continuous and reliable power supply plays an important role for water leakage monitoring systems used in urban water supply pipes. Renewable energies powered water leakage monitoring system is becoming a promising way to reduce the dependence on traditional chemical batteries. In this study, an inline vertical cross-flow turbine was developed to harvest the potential hydropower inside water supply pipes for supplying power to the water monitoring systems. Specifically, numerical investigations are carried out on the block shapes of a water turbine system to determine an optimal model. The effects of tip clearance on the turbine performance are conducted and it is found that a smaller tip clearance can reduce the reversing torque on the returning blades and increase the pressure drop through the runner for improving the turbine performance. Besides, a self-adjustable vane is designed to avoid excess water head loss. The simulation results show that the proposed self-adjustable vane is effective to limit the water head loss at high flow velocities (1.5–2.0 m/s) to 5 m. Finally, the turbine prototype is fabricated and tested on a lab test rig. The experimental results indicate that the numerical method adopted in this research is accurate enough for such micro water turbine performance prediction. A month-long test shows that the daily electricity generation of the proposed turbine is about 600 Wh and the water head loss is always below 5 m, which means that the proposed turbine can provide sufficient power for any general water leakage monitoring system without influencing normal water supply.

Ca0.15Sr1.85Bi4Ti5O18 (CSBT-0.15) ferroelectric ceramics were developed by the conventional solid-state reaction method under various sintering atmospheres. The influences of these sintering atmospheres on grain orientation, grain size, oxygen vacancies, ferroelectric properties and leakage mechanisms were systematically investigated. It was found that the samples sintered under N2 showed higher a-axis orientation and smaller grain sizes than those sintered under O2 and air. From XPS analysis, it can be observed that the amount of Ti3+ in the ceramics sintered under N2 is relatively high, which indicates a high number of oxygen vacancies in these samples. The samples sintered under N2, air and O2 all delivered well-saturated hysteresis loops with a remnant polarization (2Pr) of 13.8 μC/cm2, 12.4 μC/cm2 and 7.2 μC/cm2 and corresponding coercive fields (2Ec) of 100 kV/cm, 86 kV/cm and 80 kV/cm, respectively. At 70 kV/cm, the leakage current densities of the samples sintered under N2, air and O2 are 4.2 × 10−6 A/cm2, 1.9 × 10−6 A/cm2 and 1.0 × 10−6 A/cm2, respectively. The leakage conduction mechanism transformed from Ohmic conduction in a relatively low applied electric field range (0–15 kV/cm) to space-charge-limited conduction (SCLC) in higher electric field ranges.

Nickel-rich layered oxides are regarded as very promising materials as cathodes for lithium-ion batteries because of their environmental benignancy, low cost, and high energy density. However, insufficient cycle performance and poor thermotic characteristics induced by structural degradation at high potentials and elevated temperatures pose challenging hurdles for nickel-rich cathodes. Here, a protective pillaring layer, in which partial Ni2+ ions occupy Li slabs induced by gradient Mn4+, is integrated into the primary particle of LiNi0.815Co0.15Al0.035O2 to stabilize the surface/interfacial structure. With the stable outer surface provided by the enriched Mn4+ gradient concentration and the pillar effect of the NiO-like phase, Mn-incorporated quaternary cathodes show enhanced structural stability and improved Li+ diffusion as well as lithium-storage properties. Compared with the severe capacity fade of a pure layered structure, the cathode with gradient Mn4+ exhibits more stable cycling behavior with a c...

BiFeO3 (BFO) and transition metal (Cu, Zn, Mn) doped BFO thin films were successfully fabricated on indium tin oxide (ITO)/glass substrate using sol–gel process, spin coating and layer by layer technique. Compared to the pure BFO thin film, improved ferroelectric and leakage current properties were observed in the transition metal doped BFO thin films. The transition metal (Cu, Zn, Mn) doped BFO thin films have varying degrees of lower leakage current compared with the pure BFO film. The substitution of Cu and Zn increase the remnant polarization of BFO thin films. The values of remnant polarization (2Pr) were 120.6 and 126.7 μC/cm2 at 933 kV/cm for Cu-doped and Zn-doped BFO thin film, respectively.

Permeable asphalt pavement should be selected according to the rainfall characteristics of the project site, so as to improve the permeable performance and ensure the bearing capacity of the pavement structure. Therefore, taking a city in the central plains urban agglomeration of China as an example, the characteristics of the rainstorm intensity distribution and cumulative rainfall are analyzed, and a combination scheme of drainage surface layer asphalt pavement suitable for rainfall characteristics in this area is proposed. Then, the pavement structure design is systematically carried out based on the permeable capacity and bearing capacity. The results show that under the rainfall conditions in this area, there is no surface runoff on the permeable asphalt pavement with 120 mm drainage surface layer, which is suitable for the medium traffic grade of urban roads with cumulative equivalent axle loads of 10 million to 12 million times.

Image denoising is a prerequisite for downstream tasks in many fields. Low-dose and photon-counting computed tomography (CT) denoising can optimize diagnostic performance at minimized radiation dose. Supervised deep denoising methods are popular but require paired clean or noisy samples that are often unavailable in practice. Limited by the independent noise assumption, current unsupervised denoising methods cannot process correlated noises as in CT images. Here we propose the first-of-its-kind similarity-based unsupervised deep denoising approach, referred to as Noise2Sim, that works in a nonlocal and nonlinear fashion to suppress not only independent but also correlated noises. Theoretically, Noise2Sim is asymptotically equivalent to supervised learning methods under mild conditions. Experimentally, Nosie2Sim recovers intrinsic features from noisy low-dose CT and photon-counting CT images as effectively as or even better than supervised learning methods on practical datasets visually, quantitatively and statistically. Noise2Sim is a general unsupervised denoising approach and has great potential in diverse applications.

Additional file 1: Figure S1. Western blot anlysis of samples from different MCs patients were treated with CoCl2 (100 μM) for 24 h, or cultured in hypoxia condition for 4, 8, or 12 h.

Nano energy 0, 1-10 (2020). doi:10.1016/j.nanoen.2020.105417, The storage of renewable energy depends largely on sustainable technologies such as sodium-ion batteries with high safety, long lifespan, low cost, and non-toxicity. Pyrophosphate Na$_{3.32}$Fe$_{2.34}$(P$_2$O$_7$)$_2$ cathode could meet this requirement, however, its structural stability needs to be further enhanced for practical purposes. To overcome this problem, Na-deficient Na$_{3.32}$Fe$_{2.11}$Ca$_{0.23}$(P$_2$O$_7$)$_2$ with exceptional stability is prepared by Ca selective doping in this work. In operando synchrotron-based X-ray diffraction (SXRD) and in situ X-ray absorption near edge spectroscopy (XANES) results reveal that the prepared Na$_{3.32}$Fe$_{2.11}$Ca$_{0.23}$(P$_2$O$_7$)$_2$ is a single-phase solid-solution reaction with high reversibility. A strong correlation between the voltage curve and lattice parameters is deciphered for the first time. Additionally, the atomic-doping-engineering strategy could significantly enhance the thermal and electrochemical stability of the electrode materials, contributing to their good structural reversibility and enhanced operational safety. Specifically, after 1000 cycles at 1 C, the Ca doped electrode achieves a high capacity retention of 81.7%, which is much better than that of the un-doped electrode (15.5%). Our work may pave a new avenue for designing safe and low-cost cathode materials for battery applications with long cycle life., Published by Elsevier, Amsterdam [u.a.]

Angewandte Chemie / International edition International edition 1, 10 (2019). doi:10.1002/ange.201912964, The cathode materials for sodium‐ion batteries have always been one of the key issues for the ultimate success of large‐scale energy storage systems. Here, we introduce a 4.0 V class high‐voltage cathode material with a newly recognized sodium superionic conductor (NASICON)‐type structure with cubic symmetry (space group P 2 1 3), Na 3 V(PO 3 ) 3 N. We synthesize an N‐doped graphene oxide wrapped Na 3 V(PO 3 ) 3 N composite with a uniform carbon coating layer, and it shows both excellent rate performance and outstanding cycling stability. Its air/water stability and all‐climate performance are carefully investigated in detail. Near‐zero volume change (~0.40%) is clearly observed for the first time based on in‐situ synchrotron X‐ray diffraction, and the in‐situ X‐ray absorption spectra reveal the V 3.2+ /V 4.2+ redox reaction with high reversibility. Its three‐dimensional sodium diffusion pathways are explicitly demonstrated with distinctive low energy barriers. Higher reversible capacity and a higher working platform can surely be achieved if the electrolyte possesses a wider voltage tolerance window above 4.8 V. Our comprehensive results indicate that this high‐voltage new NASICON‐type Na 3 V(PO 3 ) 3 N composite can be considered as a competitive candidate cathode material for sodium‐ion batteries and will receive more extensive attention and studies in the future., Published by Wiley-VCH9102, Weinheim

Nickel-rich layered oxides are regarded as very promising materials as cathodes for lithium-ion batteries because of their environmental benignancy, low cost, and high energy density. However, insufficient cycle performance and poor thermotic characteristics induced by structural degradation at high potentials and elevated temperatures pose challenging hurdles for nickel-rich cathodes. Here, a protective pillaring layer, in which partial Ni

A novel complementary approach for promising anode materials is proposed. Sodium titanates with layered Na2Ti3O7 and tunnel Na2Ti6O13 hybrid structure are presented, fabricated, and characterized. The hybrid sample exhibits excellent cycling stability and superior rate performance by the inhibition of layered phase transformation and synergetic effect. The structural evolution, reaction mechanism, and reaction dynamics of hybrid electrodes during the sodium insertion/desertion process are carefully investigated. In situ synchrotron X‐ray powder diffraction (SXRD) characterization is performed and the result indicates that Na+ inserts into tunnel structure with occurring solid solution reaction and intercalates into Na2Ti3O7 structure with appearing a phase transition in a low voltage. The reaction dynamics reveals that sodium ion diffusion of tunnel Na2Ti6O13 is faster than that of layered Na2Ti3O7. The synergetic complementary properties are significantly conductive to enhance electrochemical behavior of hybrid structure. This study provides a promising candidate anode for advanced sodium ion batteries (SIBs).

The xBiFeO3-(1-x)Sr2Bi4Ti5O18(SBFTi-x, x=0, 0.1, 0.3 and 0.5) composite ferroelectric ceramics were prepared by sol-gel with self-propagating combustion method. The dielectric properties and AC impedance were analyzed. Six-layered Aurivillius structure was confirmed from the X-ray analysis. With the increasing of BiFeO3 content, Bi3+ and Fe3+ co-doped in A and B site cause the lattice distortion in SBFTi-x ceramic, and the Curie temperature continuous increasing and the dielectric peak gradually broadened due to disordered distribution of ions. Besides, The electrical structure in SBFTi-x ceramics become uniform and all samples show negative temperature coefficient characteristics. Space charge polarization and mixed relaxation processes were also found in SBFTi-x ceramics.

Contamination of feed and food by aflatoxin B1 (AFB1), one of the most toxic of the mycotoxins, is a global concern. To prevent food safety scares, and avoid subsequent economic losses due to the recall of contaminated items, methods for the rapid, sensitive and specific detection of AFB1 at trace levels are much in demand. In this work, a simple, ultrasensitive, and reliable aptasensor is described for the detection of AFB1. An AFB1 aptamer was used as a molecular recognition probe, while its complementary DNA played a role as a signal generator for amplification by real-time quantitative polymerase chain reaction (PCR). Under optimal conditions, a wide linear detection range (5.0 × 10(-5) to 5.0 ng mL(-1)) was achieved, with a high sensitivity (limit of detection (LOD)=25 fg mL(-1)). In addition, the proposed aptasensor exhibited excellent specificity for AFB1 compared with eight other mycotoxins, with no obvious Ct value change. This aptasensor can also be used in quantifying AFB1 levels in Chinese wild rye hay samples and infant rice cereal samples, demonstrating satisfactory recoveries in the range of 88-127% and 94-119%, respectively. This detection technique has a significant potential for high-throughput, quantitative determination of mycotoxin levels in a large range of feeds and foods.

Granulomatous mastitis (GM) is a rare breast disease with unknown etiology. Clinical management strategies for GM include surgery, antibiotics, and steroid treatments. As patients with GM often respond to steroids, GM is thought to be an autoimmune disease. Here we describe a case of trauma-induced GM that presented as autoimmune disease but was successfully treated by surgery without steroids. The patient showed no sign of recurrence for 11 months. This case provides useful information on both the underlying mechanisms and clinical management of GM.

National Natural Science Foundation of China [50574063, 21021002, 21003102]; Sichuan University Funds for Young Scientists, China [2011SCU11081]; Research Fund for the Doctoral Program of Higher Education, the Ministry of Education, China [20120181120103]

We investigated LiFePO_4 particles that were prepared by a hydrothermal reaction at different ingredient temperatures.The precursors and final LiFePO_4 products were characterized by X-ray diffraction (XRD),scanning electron microscopy(SEM),cyclic voltammetry(CV),and elemental analysis.The results show that ingredient temperature had a significant effect on the color and characteristics of the LiFePO_4 precursors.High purity Li_3PO_4 was obtained and the formation of Fe(OH)_3 in the precursors was inhibited by controlling the ingredient temperature carefully.In addition well-crystalline and free Fe~(3+) LiFePO_4 samples were synthesized,which greatly increased the discharge capacity of the LiFePO_4 cathode materials.At an ingredient temperature of 30℃the discharge specific capacity of the as-prepared sample was found to be 156 mAh·g~(-1) at 0.1C rate,151 mAh·g~(-1) at 0.5C rate and it remained 127 mAh·g~(-1) even at a rate of 10C while the cycling retention rate was 99%after 20 cycles.

A 23-amino acid, bifunctional, integrin-targeted synthetic peptide was evaluated for ex vivo gene delivery to rabbit bone marrow stromal cells (BMSCs). The peptide (K)16GRGDSPC consists of an amino terminal domain of 16 lysines for electrostatic binding of DNA, and a 7-amino acid integrin-binding domain at the carboxyl terminal. PcDNA3-EGFP plasmids were transfected into BMSCs by (K)16GRGDSPC and the positive cells gave out a bright green fluorescence. High levels of gene delivery of pcDNA3-TGF-β1 plasmids were obtained with 2 to 4 µg/ml DNA concentration, with (K)16GRGDSPC at an optimal peptide: DNA w/w ratio of 3:1, with a required exposure time of more than 4 h but shorter than 24 h for BMSC exposure to the peptide/DNA complexes with completely absent serum in the initial stage; with 100 µM chloroquine and at least 8 h exposure for BMSC exposure to chloroquine; with a fusogenic peptide at an optimal (K)16GRGDSPC/DNA/fusogenic peptide w/w ratio of 3:1:5; and with Lipofectamine 2000 at an optimal (K)16GRGDSPC/DNA/Lipofectamine 2000 w/w ratio of 3:1:2 at a constant DNA concentration of 2 µg/ml. Chloroquine, the fusogenic peptide and Lipofectamine 2000 all significantly promoted gene delivery, but chloroquine was more effective than the fusogenic peptide and had obvious synergistic effects with Lipofectamine 2000. Under optimal conditions, TGF-β1 gene was transfected into BMSCs without observable toxicity, and the stable expression was examined by RT-PCR and Western blot analysis. The stable transgenic cells showed obvious bands. This novel synthetic peptide, providing a new way for the use of polylysine and RGD motif in DNA vector system, is potentially well suited to ex vivo gene delivery to BMSCs for experimental and clinical applications in the field of bone tissue engineering. Copyright © 2006 European Peptide Society and John Wiley & Sons, Ltd.

In order to reduce the communication cost while keeping the localization coverage and localization accuracy high, we propose a new localization scheme for underwater wireless sensor networks, i.e., localization based on best spatial correlation distance mobility prediction (LBMP). Nodes predict their mobility pattern by utilizing the spatial correlation between the mobility of underwater nodes and get located. In order to keep the localization error small, nodes with great computation ability calculate the best spatial correlation distance for the neighbor nodes to predict their mobility pattern. LBMP defines the confidence of a node to evaluate the accuracy of mobility pattern and location prediction. By controlling the value of the confidence threshold, LBMP can guarantee the quality of mobility pattern and location prediction. Simulation experiments show that, comparing to the scheme without the selection of best spatial correlation distance, LBMP has better performance in keeping relatively high localization coverage and localization accuracy while reducing communication cost apparently.

The expression of Smad2 and Smad3 and the influence of exogenous transforming growth factorbeta1 (TGFbeta1) on them in rat bone marrow-derived mesenchymal stem cells (MSCs) cultured in vitro were investigated. The effects of different concentrations of TGFbeta1 on cell proliferation and ALP activity were detected by MTT and PNPP in MSCs respectively. The expression of Smad2 and Smad3 and the influence of exogenous TGFbeta1, on them were also examined by immunocytochemistry and Western blot assays. The exogenous TGFbeta1 induced a dose-dependent decrease in cell proliferation and a dose-dependent increase in ALP activity, which plateaued at 5 ng/ml. Smad2 and Smad3 proteins were detected only in the cytoplasm in the absence of TGFbeta1, and TGFbeta1, could stimulate the translocation of them from the cytoplasm to the nucleus. The total amount of Smad2 protein remained unchanged before and after TGFbeta1 treatment (P0.05). The expression levels of Smad3 remained unchanged after 3 h and 6 h treatment (P0.05), but decreased markedly after 24 h treatment (P0.05). It was concluded that TGFbeta1 is a latent osteoinductive factor involved in osteoblastic differentiation. Both Samd2 and Smad3 mediate TGFbeta1 signaling as downstream mediators in MSCs. The biological output of TGFbeta1 triggering the osteoblastic differentiation could be entirely determined by Smad3 in MSCs.

To study the osteogenic ability of tissue-engineered bone constructed by compounding zinc-sintered bovine cancellous bone with rabbit marrow stromal cells (MSCs) in vivo, the zinc-sintered bovine cancellous bone of beta-tricalcium phosphate (TCP) type was prepared by sintering the fresh calf cancellous bone twice and then loading it with zinc-ion. The rabbit MSCs were cultured, induced and seeded onto the zinc-sintered bovine cancellous bones. The tissue-engineered bones were then implanted into the rabbits' back muscles. The newly formed bone tissues were observed by histological methods and the areas of new osseous tissues were measured at the end of the 4th and 8th week. The zinc-sintered bovine cancellous bones alone were implanted on the other side as control. The osteogenic activity of MSCs was identified by alkaline phosphatase (ALP) staining and calcification nod chinalizarin staining. At the end of 4th week, a small amount of new bone tissues was observed. At the end of 8th week, there were many newly formed bone mature tissues. Moreover, the area of the latter was significantly larger than that of the former (P

The Dongchuang gold deposit in the Xiaoqinling are is an orogenic-type lode gold deposit. It is one of the few superlarge (>100 t Au) deposits in China. Although it has been argued that it was formed in the Mesozoic, related isotopic age data have not been reported in previous studies. Based on detailed geological study, the authors have carried out isotopic dating on various metallogenic generations. The ore-forming process of the Dongchuang gold deposit consists of four stages: coarse-grained pyrite-bearing quartz veins (stage I), fine-grained pyrite-quartz veinlets (stage II), multi-sulfides (stage III) and carbonate-quartz veinlets (stage IV). Ar-Ar dating on mineral separates of stages I, II and III yields plateau ages of 142.9±2.9 Ma, 132.2±2.6 Ma and 128.3±6.2 Ma, respectively. Sericite separates from stage II assemblage also yield an Ar-Ar isochron age of 132.6±2.7 Ma, similar to the Ar-Ar plateau age. These results suggest that the Dongchuang gold deposit was mainly formed during 143–128 Ma, coinciding with the authors' geological observations and previous hypothesis. This ore formation is coeval with the regional-tectonic transition from collisional compression to extension, strongly showing that the decompression-geothermal increase regime during compression-to-extension transition is the most conducive geodynamic environment to orogenic-type gold mineralization.

Tissue engineering has confronted many difficulties mainly as follows: 1) How to modulate the adherence, proliferation, and oriented differentiation of seed cells, especially that of stemcells. 2) Massive preparation and sustained controllable delivery of tissue inducing factors or plasmid DNA, such as growth factors, angiogenesis stimulators, and so on. 3) Development of “intelligent biomimetic materials” as extracellular matrix with a good superficial and structural compatibility as well as biological activity to stimulate predictable, controllable and desirable responses under defined conditions. Molecular biology is currently one of the most exciting fields of research across life sciences, and the advances in it also bring a bright future for tissue engineering to overcome these difficulties. In recent years, tissue engineering benefits a lot from molecular biology. Only a comprehensive understanding of the involved ingredients of tissue engineering (cells tissue inducing factors, genes, biomaterials) and the subtle relationships between them at molecular level can lead to a successful manipulation of reparative processes and a better biological substitute. Molecular tissue engineering, the offspring of the tissue engineering and molecular biology, has gained an increasing importance in recent years. It offers the promise of not simply replacing tissue, but improving the restoration. The studies presented in this article put forward this new concept for the first time and provide an insight into the basic principles, status and challenges of this emerging technology.

To develop a new generation of absorbable fracture fixation devices with enhanced biocompatibility, the biodegradation mechanism and its influence on the cellular response at the tissue/implant interface of hydroxyapatite/poly-DL-lactide (HA/PDLIA) composites were investigated in vitro and in vivo. HA/PDLIA rods were immersed in phosphate-buffered saline, or implanted in muscle and bony tissue for 52 weeks. Scanning electron microscopic and histological studies were done. The degradation rate was the slowest in vitro, slower in muscle tissue and fast in bone. In vitro, the composites degraded heterogeneously and a hollow structure was formed. In bone, the limited clearing capacity leads to the accumulation of oligomeric debris, which contribute totally to the autocatalytic effect. So, the fastest degradation and intense tissue response were seen. In muscle tissue, oligomeric debris migrated into vicinal fibers over a long distance from the original implant cavity and the tissue reactions were, however, quite moderate. For the same size organic/inorganic composite, the environment where it was placed is the major factor in determining its biodegradation process and cellular reaction. In living tissue, factors such as cells, enzymes and mechanical stress have an obvious influence on the biodegradation and biological process at the tissue/implant interface. The biocompatibility of the HA/PDLIA composites is enhanced with the incorporating of the resorbable HA microparticles.

Infrared imaging system has been applied widely in both military and civilian fields. Since the infrared imager has various types and different parameters, for system manufacturers and customers, there is great demand for evaluating the performance of IR imaging systems with a standard tool or platform. Since the first generation IR imager was developed, the standard method to assess the performance has been the MRTD or related improved methods which are not perfect adaptable for current linear scanning imager or 2D staring imager based on FPA detector. For this problem, this paper describes an evaluation method based on the triangular orientation discrimination metric which is considered as the effective and emerging method to evaluate the synthesis performance of EO system. To realize the evaluation in field test, an experiment instrument is developed. And considering the importance of operational environment, the field test is carried in practical atmospheric environment. The test imagers include panoramic imaging system and staring imaging systems with different optics and detectors parameters (both cooled and uncooled). After showing the instrument and experiment setup, the experiment results are shown. The target range performance is analyzed and discussed. In data analysis part, the article gives the range prediction values obtained from TOD method, MRTD method and practical experiment, and shows the analysis and results discussion. The experimental results prove the effectiveness of this evaluation tool, and it can be taken as a platform to give the uniform performance prediction reference.

The effect of transforming growth factor beta 1 (TGF-beta 1) gene transfection on the proliferation of bone marrow-derived mesenchymal stem cells (MSCs) and the mechanism was investigated to provide basis for accelerating articular cartilage repairing using molecular tissue engineering technology. TGF-beta 1 gene at different doses was transduced into the rat bone marrow-derived MSCs to examine the effects of TGF-beta 1 gene transfection on MSCs DNA synthesis, cell cycle kinetics and the expression of proliferating cell nuclear antigen (PCNA). The results showed that 3 microliters lipofectamine-mediated 1 microgram TGF-beta 1 gene transfection could effectively promote the proliferation of MSCs best; Under this condition (DNA/Lipofectamine = 1 microgram/3 microliters), flow cytometry and immunohistochemical analyses revealed a significant increase in the 3H incorporation, DNA content in S phase and the expression of PCNA. Transfection of gene encoding TGF-beta 1 could induce the cells at G0/G1 phase to S1 phase, modulate the replication of DNA through the enhancement of the PCNA expression, increase the content of DNA at S1 phase and promote the proliferation of MSCs. This new molecular tissue engineering approach could be of potential benefit to enhance the repair of damaged articular cartilage, especially those caused by degenerative joint diseases.

To study the osteogenic potential of cultured bone marrow stromal cells (BMSCs) transfected with transforming growth factor beta 1 (TGF-beta 1) gene in vitro, cultured BMSCs were transfected with the complexes of pcDNA3-TGF-beta 1 and Lipofectamine Reagent in vitro. The cell proliferation was detected by MTT method and the morphological features of transfected BMSCs was observed. ALP stains and PNP method were used to measure ALP activity. In addition, the collagen type I propeptides and mineralized matrixes were examined by immunohistochemical staining and tetracycline fluorescence labeling respectively. The morphological and biological characters of the transfected BMSCs were similar to those of osteoblasts and the cell proliferation was promoted. The cell layer displayed strong positive reaction for ALP stains and immunohistochemical staining. ALP activity and collagen type I expression increased remarkably after transfection. Mineralized matrixes formed earlier and more in transfected BMSCs as compared with control group. It is concluded that transfecting with TGF-beta 1 gene could promote the osteogenic potential of cultured BMSCs.

In order to investigate the effect of a new institute-designed absorbable hydroxyapatite microparticles/poly-DL-lactide (HA/PDLLA) fracture fixation devices on experimental fracture healing, 25 rabbits with a transverse transcondylar osteotomy of the distal femur were fixed intramedullary by a HA/PDLLA rod (4. 5 mm in diameter, 30–40 mm in length). The follow-up time lasted 1, 2, 4, 6 and 12 week(s). Roentgenographic, histological and ultrastructural analyses were conducted. The results showed that all osteotomies united within 6 weeks without delay. No accumulation of inflammatory cells was seen. Ultrastructural studies showed that polymorphonuclear neutrophils and macrophages were observed mainly at the 1st week, but only few were noted at the 2nd week. The inflammatory and debridement stages were not prolonged. Large amount of active fibroblasts and some chondroblasts were observed at the 2nd week, suggesting a fibrous callus stage. The main cellularity at 4th week was osteoblasts and osteocytes. Part of osteocytes had already entered the static stage at the 6th week. Our experiment showed that the HA/PDLLA had good biocompatibility, sufficient mechanical streugth and caused no delay to the fracture healing.

RGD-containing peptide (K16-GRGDSPC), characterized as non-viral gene vectors, was fabricated to modify the surface of PLGA-[ASP-PEG] matrix, which offered the foundation for gene transfer with porous matrix of gene activated later. Peptide was synthesized and matrix was executed into chips A, B and chip C. Chip C was regarded as control. Chips A and B were reacted with cross-linker. Then chip A was reacted with peptide. MS and HPLC were used to detect the MW and purity of peptide. Sulphur, existing on the surface of biomaterials, was detected by XPS. The purity of un-reacted peptide in residual solution was detected by a spectrophotometer. HPLC shows that the peptide purity was 94%–95%, and MS shows that the MW was 2 741.3307. XPS reveals that the binding energy of sulphur was 164 eV and the ratio of carbon to sulphur (C/S) was 99.746:0.1014 in reacted chip A. The binding energy of sulphur in reacted chip B was 164 eV and 162 eV, C/S was 99.574:0.4255, and there was no sulphur in chip C. Peptide was manufactured and linked to the surface of biomimetic and 3-D matrix, which offered the possibilities for gene transfer and tissue engineering with this new kind of non-viral gene vector.

To explore the possibility and condition of differentiation of bone marrow mesenchymal cells (BMSCs) to neural cells in vitro, BMSCs from whole bone marrow of rats were cultured. The BMSCs of passage 3 were identified with immunocytochemical staining of CD44 (+), CD71 (+) and CD45 (-). There were type I and type II cells in BMSCs. Type I BMSCs were spindle-shaped and strong positive in immunocytochemical staining of CD44 and CD71, whereas flat and big type II BMSCs were lightly stained. The BMSCs of same passage were induced to differentiate into neural cells by beta-mercaptoethanol (BME). After induction by BME, the type I BMSCs withdrew to form neuron-like round soma and axon-like and dendrite-like processes, and were stained positively for neurofilament (NF). The type II BMSCs did not change in the BME medium and were negatively or slightly stained of NF.

An integral optimization framework of WLAN design is proposed to enhance the WLAN performance from different stages of WLAN deployment. This framework mainly includes four core stages to optimize the WLAN network: a) efficient AP deployment, b) intelligent channel assignment and power control, c) load balancing across APs, and d) good WLAN management. The researchers or network administrators are provided with the state-of-the-art WLAN network optimization technology and analysis the weakness of every solution in the procedure of optimization. It is expected that it can be a good guide for the practical WLAN network optimization and can motivate further research in this area.

Virtual education is widely used in many fields including agricultural training and popular science. Modeling technologies and software tools for content making of virtual educations about digital plant is shortages and it is an obvious limitation of relevant applications. We present a fast modeling technology and developed a system of digital plant for virtual education. The method depends on real geometric data of plant collected by three-dimensional device, and a template-based modeling algorithm is employed for rapidly reconstruction of complex plant organs. The system consists of several modules including data processing, knowledge management, geometric modeling, graphics support and user interface. The system supports users to make education content about digital plant. Finally, some typical applications are given and some future works are discussed.