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21.
Unidirectional freeze‐casting method is used to fabricate gelatin–bioglass nanoparticles (BGNPs) scaffolds. Transmission electron microscopy (TEM) images show that sol–gel prepared BGNPs are distributed throughout the scaffold with diameters of less than 10 nm. Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetric are used to evaluate the physicochemical properties of BGNPs. Scanning electron microscopy (SEM) micrographs present an oriented porous structure and a homogeneous distribution of BGNPs in the gelatin matrix. The lamellar‐type structure indicates an improvement of mechanical strength and absorption capacity of the scaffolds. Increasing the concentration of BGNPs from 0 to 50 wt% have no noticeable effect on pore orientation, but decreases porosity and pore size distribution. Increase in BGNPs content improves the compressive strength. The absorption and biodegradation rate reduces with augmentation in BGNPs concentration. Bioactivity is evaluated through apatite formation after immersion of the nanocomposites in simulated body fluid and is verified by SEM–energy‐dispersive X‐ray spectroscopy (EDS), an element map analysis, X‐ray powder diffractometer, and FTIR spectrum. SEM images and methyl thiazolyl tetrazolium assay confirm the biocompatibility of scaffolds and the supportive behavior of nanocomposites in cellular spreading. The results show that gelatin–(30 wt%)bioglass nanocomposites have incipient physicochemical and biological properties.  相似文献   
22.
The objective of this research was to extract carnosic acid and carnosol, natural lipid-soluble antioxidants, from rosemary leaves without the use of chemical aid. Three different vegetable oils [high oleic soybean oil (HOSO), peanut oil (PO) and cottonseed oil (CO)] were used as the medium for extracting rosemary's lipid-soluble antioxidants. Dried rosemary leaves were ground into fine particles, added two of the selected vegetable oils, mixed and heated. The vegetable oil containing the extracted antioxidants was filtered from the rosemary particles and analysed using high-performance liquid chromatography (HPLC). As a control, a common extraction method using ethanol was performed to compare the oil extraction efficiency for carnosic acid and carnosol. HPLC analysis confirmed the presence of carnosic acid and carnosol in all three vegetable oil solutions. Compared to the ethanol extraction, a higher level of the carnosic acid was found in the vegetable oil solutions. Among the vegetable oils, high oleic soybean oil contained the most carnosic acid; however, there were similar amounts of carnosol in all three vegetable oil solutions. The extractions' efficacy was tested on soybean oil's (SO) oxidative stability by adding 2% (w/w) of the antioxidant–vegetable oil solution. The results obtained from peroxide value (PV) and p-anisidine value (AnV) analysis documented a significantly lower degree of oxidation in the soybean oil containing the extracted antioxidant solutions, compared to the pure soybean oil.  相似文献   
23.
CONTEXT: The "Standards, Options and Recommendations" (SOR) project, started in 1993, is a collaboration between the Federation of the French Cancer Centres (FNCLCC), the 20 French Cancer Centres and specialists from French Public Universities, General Hospitals and Private Clinics. For pediatric issues, this project is a collaboration between the FNCLCC and the French Society of Pediatric Oncology (SFOP). The main objective is the development of clinical practice guidelines to improve the quality of health care and outcomes for cancer patients. The methodology is based on literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVES: To develop a clinical practice guideline according to the definitions of Standards, Options and Recommendations for the clinical care of rhabdomyosarcoma and other soft tissue sarcoma in children and adolescents. METHODS: Data have been identified by literature search using Medline (1985-may 1997) and experts group personal references lists. The main criteria considered were incidence, risk factors, prognostic factors and efficacy of cancer treatment. Once the guideline was defined, the document was submitted for review to 14 national and international independent reviewers, and to the medical committees of the 20 French Cancer Centres and, in particular the 4 which have expertise in pediatric cancer management, for agreement. RESULTS: The main recommendations for rhabdomyosarcoma management are: 1/ diagnosis is based on appropriate clinical and radiological findings; 2/ pathological and immunohistochemical studies are essential to confirm the diagnosis; 3/ surgery must be performed by an experienced surgeon. Surgery and radiotherapy must be as conservative as possible; 4/ therapeutic strategies for rhabdomyosarcoma depend on location and extends and are based on chemotherapy, surgery and radiotherapy. Inclusion of patients in SFOP, SIOP and IRS clinical trials is recommended; 5/ treatment of metastatic rhabdomyosarcoma is based on intensive chemotherapy, and surgery with or without radiotherapy; 6/ the management of non-rhabdomyosarcoma is based on the likelihood of sensitivity to chemotherapy; 7/ at the present time, there are no clear data on which to base guidelines for timing and duration of follow-up studies in these conditions.  相似文献   
24.
Monolayer 2D MoS2 grown by chemical vapor deposition is nanopatterned into nanodots, nanorods, and hexagonal nanomesh using block copolymer (BCP) lithography. The detailed atomic structure and nanoscale geometry of the nanopatterned MoS2 show features down to 4 nm with nonfaceted etching profiles defined by the BCP mask. Atomic resolution annular dark field scanning transmission electron microscopy reveals the nanopatterned MoS2 has minimal large‐scale crystalline defects and enables the edge density to be measured for each nanoscale pattern geometry. Photoluminescence spectroscopy of nanodots, nanorods, and nanomesh areas shows strain‐dependent spectral shifts up to 15 nm, as well as reduction in the PL efficiency as the edge density increases. Raman spectroscopy shows mode stiffening, confirming the release of strain when it is nanopatterned by BCP lithography. These results show that small nanodots (≈19 nm) of MoS2 2D monolayers still exhibit strong direct band gap photoluminescence (PL), but have PL quenching compared to pristine material from the edge states. This information provides important insights into the structure–PL property correlations of sub‐20 nm MoS2 structures that have potential in future applications of 2D electronics, optoelectronics, and photonics.  相似文献   
25.
A thermodynamic analysis of propane dehydrogenation with carbon dioxide was performed using constrained Gibbs free energy minimization method. Different reaction networks corresponding to different catalytic systems, including non-redox and redox oxide catalysts, were simulated. The influences of CO2/C3H8 molar ratio (1–10), temperature (700–1000 K), and pressure (0.5–5 bar) on equilibrium conversion and product composition were studied. In the presence of CO2 with a molar ratio of CO2/C3H8 = 1, the temperature of dehydrogenation can be 30 K lower than that of dehydrogenation in the presence of steam (H2O/C3H8 = 1) and about 50 K lower than that of simple dehydrogenation without dilution to achieve 60% propane conversion. It was found that the occurrence of dry reforming of propane and coke-forming side reactions could strongly impact the equilibrium product composition of the multireaction system and, therefore, these reactions should be kinetically controlled. Comparison of the simulated reactant conversions with those reported in the literatures revealed that the experimental conversion levels of propane are far below the corresponding equilibrium values due to rapid catalyst deactivation by coke, implying that research efforts should be directed toward formulation of more active and selective catalysts.  相似文献   
26.
This article presents a new approach to investigate the kinetics of sunflower and rapeseed oils methanolysis. Due to its heterogeneous nature, the methanolysis reaction is affected by different physical properties such as mass transfer coefficients and specific surface area of the dispersed phase. Considering these parameters, a model was developed, and was evaluated by comparing the results of the model with the experimental data found in the literature. The mean absolute deviation obtained for sunflower and rapeseed oils is 0.039 mol L?1, which demonstrates the accuracy of the model. The results show that the mixing speed is more effective in the first few minutes of the process. Furthermore, at mixing speed above 700 rpm, the process is controlled only by the reactions. The rate of biodiesel production increases with increasing catalyst concentration; however, catalyst concentration above 1.5 wt% has little or no significant effect on the rate of biodiesel production. In addition, because of its higher activation energy the rapeseed oil transesterification is more temperature dependent than the sunflower transesterification.  相似文献   
27.
28.
Epirubicin (EPI) is one of the potent breast cancer (BC) chemotherapeutic agents, but its adverse effects limit its efficacy. Herein, EPI was selected to be loaded in liposomal carrier, which has been targeted by a monoclonal antibody, Herceptin. The preparation process of liposomes was a modified ethanol injection method followed by Herceptin conjugation. The in vitro cell toxicity and cellular uptake of optimum formulation against HER2+ and HER2− cancer cell lines were evaluated. The results showed that the drug loading (DL%) and encapsulation efficiency (EE%) of liposome preparation method yielded 30.62% ± 0.49% and 62.39% ± 8.75%, respectively. The average size of naked liposomes (EPI‐Lipo) and immunoliposomes (EPI‐Lipo‐mAb) was 234 ± 9.86 and 257.26 ± 6.25 nm, with a relatively monodisperse distribution, which was confirmed by SEM micrographs. The release kinetic followed Higuchi model for both naked and immunoliposomes. In vitro cytotoxicity study on three different BC cell lines including BT‐20, MDA‐MB‐453 and MCF‐7 demonstrated higher toxicity of EPI in the Herceptin conjugated form (EPI‐Lipo‐mAb) in comparison with the free EPI and EPI‐Lipo in HER2 overexpressing cell line. In addition, the cellular uptake study showed a higher uptake of immunoliposomes by MCF‐7 cells in comparison with naked liposomes. In conclusion, these data show that the targeted delivery of EPI to breast cancer cells can be achieved by EPI‐Lipo‐mAb in vitro, and this strategy could be used for breast cancer therapy with further studies.  相似文献   
29.
This paper experimentally investigates the crash responses of the empty and polyurethane foam‐filled conical tubes with shallow spherical caps under quasi‐static axial loading. To find more details about the energy absorption mechanism, finite element methods is used to simulate the crush process. In terms of finding more efficient and lighter crash absorbers particularly, the energy absorption and specific energy absorption and load ratio have been considered. The influences of the tube geometrical and material parameters such as radius of spherical region, wall thickness, length, semi‐apical angle and foam density on the energy absorption mechanism have been investigated. This study provides practical information for the use of thin‐walled tubes with shallow spherical caps as energy absorbers in aerospace applications to design reentry of sounding rocket based on foam‐filled conical tube with shallow spherical caps.  相似文献   
30.
Machines are key elements in manufacturing systems and their breakdowns can dramatically affect system performance measures. This paper proposes a new multi-objective pure integer linear programming approach for the cell formation problem with alternative process routings and machine reliability consideration. The model minimizes total cost and maximizes system reliability simultaneously. Traditional reliability evaluation approaches attempt to model the reliability of the manufacturing system as a function of its elements. These approaches have some negative aspects; therefore, instead of modeling the system reliability as an explicit objective function, we use an approach to model the effects of the machine unreliability in terms of cost and time-based effects. Using the ?-constraint method as an optimization tool for multi-objective programming, a numerical example is solved to demonstrate the capability of the proposed model in evaluating various effects of the reliability consideration.  相似文献   
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