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As thermoplastic polyurethane (TPU) elastomers possess good biocompatibility and mechanical properties similar to those of native vascular tissues, they were intended to be co-electrospun with poly(ε-caprolactone) (PCL) onto the outer surface of PCL electrospun small-diameter single-layer vascular grafts (SLVGs) in this study, combining with surface heparinization. In this work, a kind of structurally reinforced TPU+PCL/PCL small-diameter bilayer vascular graft (BLVG) was fabricated

Rapid endothelialization is crucial for in situ tissue engineering vascular grafts to prevent graft failure in the long-term. Gelatin is a promising nature material that can promote endothelial cel...

Decellularization is a promising approach in tissue engineering to generate small-diameter blood vessels. However, some challenges still exist. We performed two decellularization phases to develop an optimal decellularized scaffold and analyze the relationship between the extracellular matrix (ECM) composition and mechanical properties. In decellularization phase I, we tested sodium dodecylsulfate (SDS), Triton X-100 (TX100) and trypsin at different concentrations and exposure times. In decellularization phase II, we systematically compared five combined decellularization protocols based on the results of phase I to identify the optimal method. These protocols tested cell removal, ECM preservation, mechanical properties, and residual cytotoxicity. We further immobilized heparin to optimal decellularized scaffolds and determined its anticoagulant activity and mechanical properties. The combined decellularization protocol comprising treatment with 0.5% SDS followed by 1% TX100 could completely remove the cellular contents and preserve the mechanical properties and ECM architecture better. In addition, the heparinized decellularized scaffolds not only had sustained anticoagulant activity, but also similar mechanical properties to native vessels. In conclusion, heparinized decellularized scaffolds represent a promising direction for small-diameter vascular grafts, although further

The conversion of solar energy and water to hydrogen via semiconductor photocatalysts is one of the efficient strategies to mitigate the energy and environmental crisis. Conjugated polymeric photocatalysts have advantages over their inorganic counterparts. Their molecular structures, band structures, and electronic properties are easily tunable through molecular engineering to extend their spectral response ranges, improve their quantum efficiencies, and enhance their hydrogen evolution rates. In particular, covalent triazine-based frameworks (CTFs) present a strong potential for solar-driven hydrogen generation due to their large continuous π-conjugated structure, high thermal and chemical stability, and efficient charge transfer and separation capability. Herein, synthesis strategies, functional optimization, and applications in the photocatalytic hydrogen evolution of CTFs since the first investigation are reviewed. Finally, the challenges of hydrogen generation for CTFs are summarized, and the direction of material modifications is proposed.

Increasingly growing problems in vascular access for long-term hemodialysis lead to a considerable demand for synthetic small diameter vascular prostheses, which usually suffer from some drawbacks and are associated to high failure rates. Incorporating the concept of in situ tissue engineering (TE) into synthetic small diameter blood vessels, for example, thermoplastic poly(ether urethane) (TPU) ones, could provide an alternative approach for vascular access that profits from the advantages of excellent mechanical properties of synthetic polymer materials (early cannulation) and unique biointegration regeneration of autologous neovascular tissues (long-term fistulae). In this study, a kind of heparinized small diameter (d = 2.5 mm) TPU/poly(ε-caprolactone) (TPU/PCL-Hep) bi-layered blood vessels was electrospun with an inner layer of PCL and an outer layer of TPU. Afterward, the inner surface heparinization was conducted by coupling H

Rapid endothelialization is crucial for

The inverse synthetic aperture radar (ISAR) imaging for nonuniformly rotating target has always been a challenging task due to the time-varying Doppler parameter, especially in the low signal-to-noise ratio (SNR) environment. In this paper, a novel ISAR imaging algorithm for nonuniformly rotating targets in the low SNR environment based on the parameter estimation approach is presented. First, the received signal in this work in a range bin is modeled as a multicomponent cubic phase signal (CPS) after motion compensation. Two approaches, namely coherently integrated modified cubic phase function (CIMCPF) and coherently integrated modified high-order ambiguous function (CIMHAF), are proposed to, respectively, estimate the second-order and the third-order coefficients in the CPS. Thanks to the coherent integrations developed in both CIMCPF and CIMHAF, they demonstrate excellent low SNR performance. Moreover, to efficiently implement the proposed approach, the nonuniform fast Fourier transform (NUFFT) is utilized in this work. Due to the usage of the NUFFT, the computational cost is reduced, and the search procedure also dispenses with the nonuniformly spaced signal. Finally, CIMCPF and CIMHAF are applied to produce ISAR image for a maneuvering target based on the CPS model. Several numerical examples, analyses of the noise tolerance performance for the proposed approaches, and ISAR imaging results demonstrate the superior performance of the proposed method.

Experimental liquid viscosities of pure compounds and their mixtures are needed for the design of chemical processes in heat and mass transfers or fluid mechanics. This paper is about partial work supported by SINOPEC (China Petroleum & Chemical Corporation). The results are related to the design calculation of synthesis of purified terephthalic acid (PTA). At temperature (313.15 to 473.15) K, the viscosities of pure p-xylene, pure acetic acid, and the p-xylene + acetic acid binary system of different concentrations were determined by a rolling-ball viscometer at pressures (0.10 to 3.20) MPa. Then, the viscosity data were fitted by a correlation equation. The AAD of the correlation is 1.21 %.

Molecular dynamics (MD) simulation was employed to investigate diffusion behavior of small penetrants in rubbery-polymer-based hybrid membranes, using pervaporative removal of benzene from its dilute solution by poly(dimethylsiloxane) (PDMS) membranes filled with calix[4]arene (CA) as the model system. In our previous experimental investigation, the normalized permeation rate of benzene (NPRb) and separation factor (benzene/water) through PDMS−CA hybrid membranes did not follow the usual monotonous or single peak/valley change, but accompanied minimum and maximum values instead. In the present study, nonbonding interaction energy between PDMS and CA, mean-square displacement (MSD), free volume characteristics, and diffusion coefficients of benzene and water in pure PDMS and hybrid membranes were analyzed by molecular dynamics simulation. The simulation results revealed that MSD and fractional free volume (FFV) values were closely dependent on interaction energy. Diffusion coefficients of benzene and water...

The study was conducted to evaluate the pharmacokinetic disposition of difloxacin (DIF) with a single dose of 20 mg/kg body weight after oral administration in crucian carp ( Carassius auratus , 250 ± 30 g) at water temperatures of 10 °C and 20 °C. DIF concentration in plasma and tissues was determined using high-performance liquid chromatography (HPLC). The plasma drug concentration–time data were fitted using a single-compartment model and a two-compartment model at 10 °C and 20 °C, respectively. The absorption rate constant ( K a ) of DIF was found to be 0.85 and 1.27 h − 1 at 10 °C and 20 °C, respectively, whereas the elimination half-life ( t 1/2 β ) of the drug was 95.36 h at 10 °C and 48.93 h at 20 °C. The area under the serum concentration–time curve (AUC) was 1361.79 μg ml − 1 h at 10 °C and 355.19 μg ml − 1 h at 20 °C. The distribution volume ( V d / F ) of DIF was computed as 2.02 and 4.02 l kg − 1 at 10 °C and 20 °C, respectively. The total clearance of DIF (CL b ) was estimated to be 0.015 and 0.056 l h − 1 kg − 1 at 10 °C and 20 °C, respectively. The time-point of maximum plasma concentration of the drug ( T p ) and the maximum plasma concentration ( C max ) were calculated as 5.65 h and 9.49 μg/ml at 10 °C and 2.21 h and 10.28 μg/ml at 20 °C. After repeated oral administration at a dosage of 20 mg/kg body weight, DIF was detected in the muscle, liver, kidney, and skin for 15 days after the last administration. The results revealed that the depletion of DIF in the crucian carp becomes slower with a long half-life time, especially at lower water temperature.

Mathematical models for the effects of the calcination process conditions on the mechanical properties of a PCoMo/Al 2 O 3 hydrotreating catalyst are developed using a response surface methodology. A central composite design is performed to study collectively the effects of calcination temperature, calcination time and heating rate on the mean strength and Weibull's modulus. A model is obtained for each response with multiple regression analysis and then is refined. Analysis of variance reveals that the models developed are adequate. The validity of the models is also verified by experimental data. Statistics reveals that there is a great potential for increasing the mechanical reliability in the calcination process. Analysis of response surface show that the mean strength and Weibull's modulus increase with the increase of calcination temperature. The middle level of heating rate results in smaller mean strength and higher Weibull's modulus. The mean strength increases as calcination time increases. However, calcination time has no significant effect on Weibull's modulus in the experimental domain examined.

Mechanical-strength measurement methods for differently shaped solid catalysts, such as crushing, knife-edge cutting and three-point bending have been discussed. The strength data were correlated by Weibull distribution. Experimental results show that, except for the crushing strength test on extruded catalysts, all strength tests have a single fracture mode, and the strength failures are due to brittle fracture, originating from tensile stress concentration at the edges of the existing flaws in the catalyst pellets. The suitability of different test methods for spheres, tablets and extrudates, respectively, are discussed. It is concluded that the crushing test is a satisfactory method for spheres, and crushing and cutting tests are both suitable for tablets, while cutting and bending tests are appropriate for extrudates.

The applicability of a model developed for the bulk crushing strength of spherical catalysts has been extended to differently shaped nonspherical catalysts such as extrudates. A broken percentage for a spherical catalyst and a percentage of fine particles for other shaped ones generated during the bulk crushing strength measurement are discussed and used as indices for strength. A good correlation has been obtained between the model-predicted values and the experimental results of differently shaped extruded catalysts. It has also been found that the slope factor in the model does not change with the size of the sieve; it is thus suggested that one group of data obtained with an appropriate sieve is informative for strength analysis.

Statistics reveal that horizontal crushing strength data scatter in rather large ranges for cylindrical iron-based high-temperature water-gas shift catalyst tablets. This scattering is due to brittle fracture nature of the strength failure, originating from the stress concentration around edges of existing micro-cracks, such as pores, defects, and discontinuations contained in tablets. However, variations in the tablet size and density are found to contribute to strength data scattering. Data of tablet strength, height and density of the catalysts are found to be scattered in different ranges and to follow Weibull distribution, respectively. Based on the statistical data from a number of commercial catalysts, strength failure probability is proposed as the critical parameter for quality control. Catalyst tablet texture is examined, and it is observed that the tablets with strength close to low end of strength distribution have higher porosity, lower density and larger pore size in comparison with those near high end. For catalyst tablets, low strength is related to increased risk of strength failure, and high strength would result in lower catalyst efficiency. Catalyst tablet strength distributed in a narrow window is beneficial for commercial application. A correlation between catalyst tablet density and strength is established using a model proposed by Knudsen. Results obtained by analysing these interrelated parameters indicate that optimisation of catalyst tablet mechanical strength can be achieved through monitoring and controlling material properties and processing parameters during preparation.

Statistics and experiments reveal that the mechanical failure of a spherical catalyst under single-particle crushing strength and bulk crushing strength tests are both brittle fracture and the fact that the single particle strength data follow a Weibull distribution. A model is proposed for the packing of spherical particles, which assumes tetrahedral contact and force transmission between the spheres. A deduction from this packing is that the broken percentage of spheres during bulk strength measurement follows the relationship of the Weibull equation. Experimental results confirm this conclusion, which relates the single particle property and the bulk behavior of the packed bed of catalytic materials.

The ETS family of transcription factors regulate several critical cellular functions. They have also been implicated in invertebrate ocular development. This work was undertaken to determine whether epithelium-specific ETS transcription factors are expressed in the retinal pigment epithelium and to investigate the possible role of these factors in retinal diseases such as age-related macular degeneration.The expression of the epithelial ETS transcription factors ELF5, ESE3, and ELF3 was assessed by RT-PCR in the human RPE cell lines D407 and hTERT-RPE1. The full-length coding sequence of rat Elf3 was isolated with 3' rapid amplification of cDNA ends (RACE) and degenerative primers, and its expression was determined in various rat tissues, by RT-PCR and real-time PCR. A polyclonal ELF3 antibody produced from a C-terminal peptide was used to observe the distribution of the transcription factor within the retina. To assess the possible ELF3 regulation of the TIMP3 promoter, transient transfection assays were performed. Promoter activity was determined with a firefly luciferase reporter gene construct.The epithelium-specific ETS transcription factor ELF3 was expressed in the D407 and hTERT-RPE1 cell lines. Neither ESE3 nor ELF5 was detected in the RPE. The cloning of rat Elf3 produced two splice variants, designated Elf3a (1786 bp) and Elf3b (1855 bp). The larger form, Elf3b, contained a 69-bp insert in the coding sequence, which showed high homology to a similar insert previously identified in murine Elf3. Both splice variants were expressed in rat lung, kidney, liver, and retina, but were absent in heart tissue. Real-time PCR analysis showed the retina to contain high levels of Elf3, which was subsequently localized to the RPE. Elf3 upregulated the TIMP3 promoter, with Elf3a and -3b inducing an approximate sixfold increase in activity.The ELF3 transcription factor is highly expressed in the RPE and can regulate important ocular genes, such as TIMP3, in vitro. The specific expression of ELF3 in the RPE may reflect an important role for this transcription factor in retinal function. Furthermore, its regulation of TIMP3 may have implications for degenerative retinal diseases, such as age-related macular degeneration.

Background The introduction of rituximab has improved the complete remission(CR) rate of EBV-associated posttransplant lymphoproliferative disease(PTLD), thus the recurrence of PTLD becomes the main cause affecting long-term survival, which is closely related with the reestablishment of immune functions. Unfortunately, PTLD happens generally at the early stage of transplants and the reconstitution of immunocompetence needs for 3-5 years in the recipients of allo-HSCT. In this study, a sequential therapeutic strategy that based on rituximab followed by adoptive cellular therapies (G-CSF mobilized donor lymphocyte infusion (DLI) or EBV-specific cytotoxic T lymphocyte infusion (EBV-CTL)) was evaluated for decreasing relapse of PTLD. Methods Fifty-two patients with EBV-PTLD were enrolled in this prospective study. Once PTLD was diagnosed,immunosuppressants would be withdrawn in a stepwise fashion (ie, total dose reduced by 20%/week)if the condition of the patient was acceptable. The rituximab-based treatments (rituximab alone or combined with chemotherapy) were administrated based on PTLD histopathology and the blood cells counts. After CR or 2 cycles of rithuximab-based treatments, DLI or EBV-CTL therapy would be performed in this cohort. The rituximab-based treatments would be discontinued once patient obtained CR, and DLI would be performed once Monthly till GVHD occurred or for a total of 4 doses and EBV-CTL infusion would be performed every two weeks till GVHD occurred or for a total of 8 doses . Results After 2 cycles of the rituximab-based treatments, 37 patients obtained complete remission (CR), 8 obtained partial remission (PR), and 7 no remission (NR), including 4 died of PTLD progression. The CR rate of 2 cycles of rituximab-based treatments was 71.2%. After rituximab-based treatments combined with the adoptive cellular therapies, 9 obtained CR and 2 died of PTLD progression in 11 patients who did not achieve CR within 2cycles of rituximab-based treatments. The CR rate of 2 cycles of rituximab-based treatments combined with cellular therapies was 88.5%. Seven patients experience acute GVHD (aGVHD) (grade I in 1 and grade II in 6) and 8 chronic (cGVHD) (limited cGVHD in 5 and extensive cGVHD in 3) in 39 patients underwent a median 4 doses of DLI. One patient experienced grade II aGVHD and 2 limited cGVHD in 8 patients underwent a median of 7 doses of EBV-CTL. There were no differences in incidence of aGVHD(P=1.000) and cGVHD(P=1.000) between the patients received DLI and CTL. Within a median follow-up of 632 (range, 21 to 1651) days, one patient experienced PTLD relapse, and the 4 year cumulative incidence of PTLD relapse and primary malignancy relapse was 5.3%±5.1% and 6.2±4.3%, respectively. The 4 year cumulative overall survival (OS) after PTLD and disease(PTLD)-free survival were 66.2%±7.1% and 65.9±7.3%, respectively. Conclusions Rituximab-based treatments combined with the adoptive cellular therapies might elevate PTLD CR rate, and decrease the relapse in the recipients of allo-HSCT. Disclosures: Liu: It was supported by 863 Program (No. 2011AA020105), National Public Health Grand Research Foundation (Grant No. 201202017): Research Funding; It was supported by National Natural Science Foundation of China (Grant No.81000231, No.81270647) and Science and Technology Program of Guangzhou of China(11A72121174): Research Funding.