Osteoarthritis (OA) is the leading cause of joint pain and disability in middle-aged and elderly patients, and is characterized by progressive loss of articular cartilage that eventually leads to a ...complex process involving degradation of various components of the cartilage matrix, chief among them are the cartilage-specific type II collagen (CII) and aggrecan. While the loss of aggrecan is thought to be an early and reversible process, degradation of CII is considered to be irreversible and a key step in the loss of structural and functional integrity of cartilage. Among the various matrix metalloproteinases (MMPs), MMP-13 is specifically expressed in the cartilage of human OA patients and is not present in normal adult cartilage. It is the major collagenase in OA cartilage and has the highest activity against CII. However, the clinical utility of broad-spectrum MMP inhibitors developed for treatment of OA has been restricted by dose- and duration-dependent musculoskeletal side effects in humans. Consequently, selectively inhibiting the MMP-13 would seem to be an attractive therapeutic objective. This review mainly focuses on selective MMP-13 inhibitors development in terms of OA since the late 90s, in terms of synthetic compounds of low molecular mass incorporating specific zinc-binding groups, non-zinc-binding groups. In addition, dual inhibitors of MMP-13 and aggrecanase are also reviewed. Special emphasis is placed on logistic concerns for lead compound search as well as the structure-activity relationship (SAR) in this field. Through these methods, new hope is emerging for the treatment of OA through selective inhibition of MMP-13.
•Hydroconversion of Jatropha oil into iso-paraffin was achieved in one catalytic step.•The medium acid sites in SAPO-11 increased with the increase of Si/Al ratio.•Hydrotreatment of Jatropha oil was ...performed at various LHSV and Si/Al.•The mechanism of hydroconversion of methyl oleate was investigated.•A reaction network for hydroconversion of Jatropha oil was suggested.
A series of Pt/SAPO-11 catalysts were prepared with various Si/Al ratios and Pt loadings and characterized by using BET, XRD, XRF, and CO pulse adsorption, as well as 29Si NMR and NH3-TPD techniques. Their catalytic performances in hydroconversion of Jatropha oil were tested with a fixed-bed flow reactor system. The isomerization activity increased with the Si/Al ratio because there were more medium acidic sites on the SAPO-11 supports. Pt/SAPO-11 catalysts with a Si/Al ratio of 0.4 demonstrated high activity for both deoxygenation and isomerization among catalysts with the same Pt loading. The deoxygenation, isomerization and cracking activities strongly depended on the Pt loading. The best activity was observed for the sample with a 3wt% Pt loading, which generated an 83% yield of iso-C15-18 hydrocarbons under the LHSV of 0.5h−1. Based on the mechanistic study of hydroconversion of methyl oleate, a reaction network for the hydroconversion of Jatropha oil was suggested.
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•PtSn/SAPO-11 shows high hydrodeoxygenation activity and isomerization selectivity.•The active phase in Sn-promoted Pt/SAPO-11 in ester hydrogenation was identified.•High ...hydrodeoxygenation activity is linked to a synergistic effect of Pt–SnO2−x.•The presence of Pt–Sn alloys improves isomerization selectivity.
SAPO-11 zeolite-supported PtSn bimetallic catalysts (PtSn/SAPO-11) were prepared using a co-impregnation method for simultaneous selective hydrodeoxygenation of methyl palmitate and isomerization of deoxygenated hydrocarbons. The PtSn catalyst exhibited high isomerization activity and hydrodeoxygenation selectivity, and was superior to the monometallic Pt/SAPO-11 catalyst. The Pt/SAPO-11 catalyst was more active for CC bond cleavage, resulting in a considerable formation of C15 hydrocarbons. The PtSn/SAPO-11 catalyst was more efficient for CO bond hydrogenation, affording higher selectivity to C16 hydrocarbons. In the studied PtSn catalyst, the platinum content was constant at 0.3wt% and the atomic ratio of Sn/Pt was varied from 1 to 3. The result of the catalytic test suggests that it is necessary to control tin surface density in order to obtain a well-balanced Pt–SnO2−x function and a Pt–Sn alloy as well. The highest performance in the tandem hydrodeoxygenation–isomerization of methyl palmitate was observed at the Sn/Pt ratio of 2; for this catalyst, the isomerization yield obtained at 375°C was 4 times higher than the monometallic Pt catalyst. After tin addition, Pt nanoparticles were highly dispersed on the support with an average size of ∼4nm. HRTEM observations and FT-IR studies of CO adsorption indicate that a portion of Sn interacted with Pt, forming Pt–Sn alloys; other Sn species were formed in the form of tin oxides, likely SnO2−x (0<x<2), and were mainly present on the periphery of Pt nanoparticles. The occurrence of SnO2−x species is crucial for the hydrodeoxygenation pathway; however, excessive addition of tin would block the Pt and PtSn active sites, resulting in a decrease in the catalytic activity. The presence of Pt–Sn alloys is the most remarkable reason for its high isomerization activity.
Ti-inserted ordered mesoporous silica SBA-15 (Ti-SBA-15) synthesized by original microwave-assisted method as a support was used to prepare CoMo catalysts to develop a new catalyst with high ...hydrodesulfurization (HDS) and controlled hydrodearomatization (HDA) activities. The activity tests of catalysts were carried out by using a pressurized fixed-bed flow reactor. 4,6-Dimethyldibenzothiophene (4,6-DMDBT), 1-methylnaphthalene, and phenanthrene were used as model reactants in HDS and HDA, respectively. CoMo/Ti-SBA-15 catalyst showed about 1.35 times of HDS activity and half of HDA activity of CoMo/SBA-15 catalyst. The results of XRD, FT-IR and 29Si-NMR reveal that titanium was successfully inserted into silica framework of SBA-15, and the SBA-15 mesoporous structure was maintained after insertion of titanium. The reduction of molybdenum from Mo6+ to Mo4+ readily occurred with incorporation of titanium, resulting in an increase in Mo4+ species and CoMoS phase on sulfided catalysts. This enhanced the HDS activity of CoMoTiSBA15 catalyst. Moreover, the presence of Ti3+ on CoMo/Ti-SBA-15 was observed, suggesting that TiMoS was formed and played a role as new active sites. CoMoS active slabs with shorter length and higher stacking layer were formed on CoMo/Ti-SBA-15 comparing with CoMo/SBA-15, resulting in the low HDA activity of the former.
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•CoMo/Ti-SBA-15 catalyst with high hydrodesulfurization and low hydrodearomatization activities was developed.•Titanium was successfully inserted into SBA-15 framework, and the SBA-15 mesoporous structure was maintained.•Titanium insertion enhanced the reduction of active metals and the formation of CoMoS and TiMoS active phases.
•The AC–Bi2O3 composite was synthesized by vacuum impregnation and roasting process.•The capacitance of AC–Bi2O3 is 332.6Fg−1 in 6M KOH at specific current of 1Ag−1.•The capacitance of AC–Bi2O3 is ...about 3 times larger than that of AC (106.5Fg−1).•The AC–Bi2O3 electrode can keep 59% of initial capacitance over 1000 cycles.
To improve the capacitance of activated carbon (AC) supercapacitors, the activated carbon–bismuth oxide (AC–Bi2O3) composite was synthesized by vacuum impregnation and roasting process. The morphology and phase structure of the AC–Bi2O3 composite was characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), Fourier transform infrared spectrum (FTIR), X-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). The electrochemical performance (cyclic voltammetry (CV), galvanostatic charge discharge tests and electrochemical impedance spectroscopy (EIS)) of the AC electrode and the AC–Bi2O3 electrode was characterized on the electrochemical workstation. It was found that the capacitance of AC–Bi2O3 composite is 332.6Fg−1 in 6M KOH by chronopotentiometry at a specific current of 1Ag−1 and the specific capacitance is more than 3 times larger than that of activated carbon (106.5Fg−1) at the same condition. In addition, the composite also displays a low resistance and a good stability. These results show that AC–Bi2O3 composite is a very promising electrode material for high-performance supercapacitors.
The catalytic transesterification of vegetable oil over heterogeneous catalysts is an effective approach for biodiesel production. To elucidate the role of MgO in catalyzing this reaction, several ...CaO-MgO catalysts with various Mg/Ca ratios were synthesized by co-precipitation. The catalysts were characterized by BET, XRD, SEM, HRTEM, FTIR, TGA, CO
2
-TPD, O
2
-TPO, and in situ DRIFTS. The catalytic performance in the transesterification of soybean oil with methanol was evaluated in a stirred batch reactor. The results indicated that the synthesized pure MgO had weak basic sites and poor pore structure, showing the lowest activity. The added Mg in the CaO-MgO composites was present in both doped and supported forms. The doped Mg reduced the lattice spacing of CaO, improved the intensity and number of basic sites, and enhanced the activity of catalysts, while the supported Mg hindered the diffusion of reactants to the basic sites. The amount of the doped Mg showed a maximum value due to the solubility nature of CaCO
3
and MgCO
3
. 1Mg3Ca (Mg/Ca=1/3) exhibited the highest activity with a biodiesel yield of 92.28% at 60 °C for 2 h. CaO is sensitive to water and CO
2
, forming hydroxides and carbonates. The supported MgO with a low porous structure well protected the basic sites from contamination. High-temperature treatment is an effective method to remove the contaminates and the removal temperature increases in the order of H
2
O < Mg(OH)
2
< Ca(OH)
2
< CaCO
3
.
To compare the reproducibility of apparent diffusion coefficient (ADC)-based radiomic features between readout-segmented echo-planar diffusion-weighted imaging (RESOLVE) and single-shot echo-planar ...diffusion-weighted imaging (SS-EPI DWI) in cervical cancer.
The RESOLVE and SS-EPI DWI images of 36 patients with histopathologically confirmed cervical cancer were collected retrospectively. Two observers independently delineated the whole tumour on RESOLVE and SS-EPI DWI, and then copied them to the corresponding ADC maps. Shape, first-order, and texture features were extracted from ADC maps in the original and filtered (Laplacian of Gaussian LoG and wavelet) images. Thereafter, 1,316 features were generated in each RESOLVE and SS-EPI DWI, respectively. The reproducibility of radiomic features was assessed using intraclass correlation coefficient (ICC).
In the original images, RESOLVE showed 92.86%, 66.67%, and 86.67% of features with excellent reproducibility in shape, first-order, and texture features, while SS-EPI DWI showed 85.71%, 72.22%, and 60% of features with excellent reproducibility, respectively. In the LoG and wavelet filtered images, RESOLVE had 56.77% and 65.32% of features with excellent reproducibility and SS-EPI DWI had 44.95% and 61.96% of features with excellent reproducibility, respectively.
Compared with SS-EPI DWI, the feature reproducibility of RESOLVE was better in cervical cancer, especially for texture features. The filtered images cannot improve the feature reproducibility compared with the original images for both SS-EPI DWI and RESOLVE.
•Excellent feature reproducibility is critical for establishing radiomics models.•Improved image quality produces better reproducibility of radiomics features.•Filtered images result in poor feature reproducibility in diffusion-weighted imaging.
Stojicic S, Shen Y, Qian W, Johnson B, Haapasalo M. Antibacterial and smear layer removal ability of a novel irrigant, QMiX. International Endodontic Journal, 45, 363–371, 2012.
Aim To assess in a ...laboratory experimental model the efficacy of a novel root canal irrigant, QMiX, against Enterococcus faecalis and mixed plaque bacteria in planktonic phase and biofilms. In addition, its ability to remove smear layer was examined.
Methodology Enterococcus faecalis and mixed plaque bacteria were exposed to QMiX, 2% chlorhexidine (CHX), MTAD and 1% sodium hypochlorite (NaOCl) for 5 s, 30 s and 3 min. Following exposure, samples were taken, serially diluted and grown aerobically and anaerobically on tryptic soy agar (TSA) plates or on blood agar plates for 24 and 72 h, respectively, to measure killing of bacteria. E. faecalis and plaque biofilms were grown for 3 weeks on collagen‐coated hydroxyapatite or dentine discs and exposed for 1 and 3 min to QMiX, 2% CHX, MTAD, 1% and 2% NaOCl. The amount of killed bacteria in biofilms was analysed by confocal laser scanning microscopy using viability staining. Dentine blocks were exposed to QMiX and 17% EDTA for 5 min. The effectiveness of smear layer removal by the solution was evaluated using scanning electron microscopy. For statistical analysis, one‐way analysis of variance and comparison of two proportions were used.
Results QMiX and 1% NaOCl killed all planktonic E. faecalis and plaque bacteria in 5 s, while 2% CHX and MTAD were unable to kill all plaque bacteria in 30 s, and some E. faecalis cells survived even 3 min of exposure. QMiX and 2% NaOCl killed up to 12 times more biofilm bacteria than 1% NaOCl (P < 0.01), 2% CHX (P < 0.05; P < 0.001) and MTAD (P < 0.05; P < 0.001). QMiX removed smear layer equally well as EDTA (P = 0.18 × 10−5).
Conclusion QMiX and NaOCl were superior to CHX and MTAD under laboratory conditions in killing E. faecalis and plaque bacteria in planktonic and biofilm culture. Ability to remove smear layer by QMiX was comparable to EDTA.
Hydrotreatment of nonedible jatropha oils over PtPd/Al2O3 catalyst and NiMoP/Al2O3 catalysts was investigated under conditions of 330–390 °C, 3 MPa and 2 h–1 in a fixed-bed reactor. A significantly ...high yield range of about 82 wt % of liquid hydrocarbon products was achieved over all catalysts. Moreover, the liquid hydrocarbon products have low acid number, suitable density and viscosity, and quite high cetane index. The oil can be a high-performance additive for diesel oil. The oxygen removal pathway of jatropha oil over PtPd/Al2O3 catalyst is primarily compiled through decarboxylation and/or decarbonylation, but over NiMoP/Al2O3 catalysts, the oxygen removal pathways are executed primarily by hydro-deoxygenation. A long-term experiment was conducted over catalyst A (NiMoP/Al2O3). Results show that catalyst A starts deactivation from reaction time of 120 h. The sulfide catalyst conversion to oxide catalyst is regarded as the main reason for deactivation. The deactivated catalyst can be reused after regeneration treatment.
