Improvement of the stability of blue phosphorescent dopant material is one of the key factors for real application of organic light-emitting diodes (OLEDs). In this study, we found that the ...intramolecular hydrogen bonding in an ancillary ligand from a heteroleptic Ir(III) complex can play an important role in the stability of blue phosphorescence. To rationalize the role of intramolecular hydrogen bonding, a series of Ir(III) complexes is designed and prepared: Ir(dfppy)2(pic-OH) (1a), Ir(dfppy)2(pic-OMe) (1b), Ir(ppy)2(pic-OH) (2a), and Ir(ppy)2(pic-OMe) (2b). The emission lifetime of Ir(dfppy)2(pic-OH) (1a) (τem = 3.19 μs) in dichloromethane solution was found to be significantly longer than that of Ir(dfppy)2(pic-OMe) (1b) (τem = 0.94 μs), because of a substantial difference in the nonradiative decay rate (k nr = 0.28 × 105 s–1 for (1a) vs 2.99 × 105 s–1 for (1b)). These results were attributed to the intramolecular OH···OC hydrogen bond of the 3-hydroxy-picolinato ligand. Finally, device lifetime was significantly improved when 1a was used as the dopant compared to FIrpic, a well-known blue dopant. Device III (1a as dopant) achieved an operational lifetime of 34.3 h for an initial luminance of 400 nits compared to that of device IV (FIrpic as dopant), a value of 20.1 h, indicating that the intramolecular hydrogen bond in ancillary ligand is playing an important role in device stability.
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IJS, KILJ, NUK, PNG, UL, UM
AbstractIn this study, the coefficient of lateral earth pressure at rest (K0) for sand subject to freezing and thawing was investigated, focusing on the effect of pore water volume. Unfrozen (UF), ...frozen (FR), and thawed (TH) conditions were all addressed and considered in the investigation. Experimental testing programs were established and conducted to characterize the values of K0 for different degrees of saturation (Sr) and relative densities. The effects of freezing and thawing on K0 were significant for the fully saturated condition of Sr=100%, whereas they were negligible for partially saturated or unsaturated conditions. For FR condition, the values of K0 were low during the early loading stage and increased gradually as σv′ increased due to the breakage of pore ice. The lower K0 values for FR condition were more significant for higher Sr. After thawing, a net volume increase was observed for Sr=100%, thereby an increase in K0 took place. This phenomenon was suggested as an important aspect for the stability of retaining structures during thawing periods. The computerized tomography images and the shear wave velocities for UF and TH conditions confirmed the effect of Sr on K0. A K0 estimation method considering the effect of freezing and thawing was proposed, showing an improved prediction of K0.
Expandable foam grout (EFG) is a novel flowable cementitious material for filling underground cavities. This study evaluates the permanent deformation behavior of EFGs under cyclic loading. EFG ...consists of cement, water, and admixture. EFG samples are mixed at a water–cement ratio of 100% and an admixture content of 5.6% to prepare cylindrical specimens cured at four different times. Sinusoidal loads with different maximum axial stresses are vertically applied. The permanent deformation of EFG increases with the number of load cycles but at a decreasing rate. A power function model is used to represent the relation between the permanent deformation and number of load cycles. The model generally matches the measured values but can overestimate the deformation at specific strain levels and curing times. The accumulated permanent deformation increases with the applied axial stress and decreases with longer curing times. The final permanent deformation decreases with the increase in the curing time, and the rate of final permanent deformation also decreases. A linear relationship is found between the final permanent deformation and unconfined compressive strength. These findings can help estimate the damage and durability of underground structures backfilled with highly flowable and expandable cementitious materials under cyclic loads.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The prevalence of rotator cuff repair is increasing; however, no study has assessed patients who have returned to golf activity after arthroscopic rotator cuff repair.
The subjects of the survey were ...633 patients who were at least two years postoperative after rotator cuff repair from January 2005 to December 2017. From August 2019 to October 2019, survey responses were collected via an online questionnaire or phone calls and a total of 197 patients were reviewed retrospectively to study about returning to golf after rotator cuff repair. The detailed survey included 12 questions specific to the patient's golf career, performance, time of return to play, and symptoms related to golf activity. Depending on the size of the rotator cuff tear, each question was statistically analyzed to determine whether there were differences in the time of return to golf, uncomfortable symptoms when golfing, and distance of the driving.
Of the 197 patients who underwent arthroscopic rotator cuff repair, there were 145 patients (73.6%) returned to golf. In the analysis results of 145 patients, the longer the golf career, the greater the chance of returning to golf. Sixty (30.5%) people returned to golf at 1 year after surgery. Twenty-one patients (10.7%) improved and 46 patients (23.4%) maintained their driving distance, whereas 78 patients (39.6%) had a worse driving distance after surgery. Ten patients (5.1%) improved and 97 patients (49.2%) maintained their golf score, but 38 patients (19.3%) had worse golf scores after surgery. Symptoms when playing golf were reported in the order of no symptoms (62.1%), a limited range of motion (13.1%), muscle weakness (11.1%), and anxious about their operated shoulder (10.3 %). Men were 6.9 times more likely to return to golf than women (odds ratio, 6.9; 95% confidence interval, 3.2-14.8). The younger the age and the shorter the time since surgery, the higher the golfing return rate. The rate of returning to golf was high in the group of patients with good tissue quality during surgery (odds ratio, 3.9; 95% confidence interval, 0.01–2.6).
The golfing return rate after arthroscopic rotator cuff repair was higher than expected (73.6%) and most players returned at 1 year after surgery. Especially, in the case of young males, their golf scores were maintained or improved and they were able to return to golf earlier after surgery. Better tissue quality in the intraoperative torn tendon was associated with a greater chance of returning to golf.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lung cancer is one of the most common reasons for cancer-induced mortality across the globe, despite major advancements in the treatment strategies including radiotherapy and chemotherapy. Existing ...reports suggest that CXCR4 is frequently expressed by malignant tumor and is imperative for vascularization, tumor growth, cell migration, and metastasis pertaining to poor prognosis. In this study, we infer that CXCR4 confers resistance to ionizing radiation (IR) in nonsmall cell lung cancer (NSCLC) cells. Further, on the basis of colony forming ability, one finds that drug-resistant A549/GR cells with improved CXCR4 expression exhibited more resistance to IR than A549 cells evidenced along with a reduction in the formation of γ-H2AX foci after IR. Transfection of shRNA against CXCR4 or treatment of pharmacological inhibitor (AMD3100) both led to sensitization of A549/GR cells towards IR. Conversely, the overexpression of CXCR4 in A549 and H460 cell lines was found to improve clonogenic survival, and reduce the formation of γ-H2AX foci after IR. CXCR4 expression was further correlated with STAT3 activation, and suppression of STAT3 activity with siSTAT3 or a specific inhibitor (WP1066) significantly stymied the colony-forming ability and increased γ-H2AX foci formation in A549/GR cells, indicating that CXCR4-mediated STAT3 signaling plays an important role for IR resistance in NSCLC cells. Finally, CXCR4/STAT3 signaling was mediated with the upregulation of Slug and downregulation of the same with siRNA, which heightened IR sensitivity in NSCLC cells. Our data collectively suggests that CXCR4/STAT3/Slug axis is paramount for IR resistance of NSCLC cells, and can be regarded as a therapeutic target to enhance the IR sensitivity of this devastating cancer.
Hypoxia stimulates hepatocellular carcinoma (HCC) cell growth via hexokinase (HK) II induction, and alternatively, HK II inhibition
induces apoptosis by activating mitochondrial signaling. This study ...was to investigate whether the induction of HK II by hypoxia
is associated with enhanced mitochondrial stability and to confirm the apoptosis-inducing efficacy of HK II inhibitor in an
in vivo model of HCC. Mitochondrial stability was examined by treating isolated mitochondria with deoxycholate, a permeability-enhancing
agent. Alteration of permeability transition pore complex composition was analyzed by immunoprecipitation and immunoblotting.
An in vivo model of HCC was established in C3H mice i.d. implanted with MH134 cells. The antitumor efficacy of i.p. given 3-bromopyruvate
(3-BrPA), a HK II inhibitor, was evaluated by measuring tumor volumes and quantifying apoptosis using terminal deoxynucleotidyl
transferase–mediated dUTP nick end labeling staining and 99m Tc-hydrazinonicotinamide-Annexin V scans. Hypoxia enhanced mitochondrial stability, and this was inhibited by 3-BrPA treatment.
In particular, HK II levels in permeability transition pore complex immunoprecipitates were reduced after 3-BrPA treatment.
In mice treated with 3-BrPA, mean tumor volumes and tumor volume growth were found to be significantly reduced. Moreover,
percentages of terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling–positive cells were significantly increased
in 3-BrPA–treated mice, and this apoptosis-inducing efficacy was reflected in vivo by 99m Tc-hydrazinonicotinamide-Annexin V imaging. Our results show that hypoxia enhances mitochondrial stability via HK II induction
and that HK II inhibitor treatment exhibits an in vivo antitumor effect by inducing apoptosis. Therefore, HK II inhibitors may be therapeutically useful for the treatment of advanced
infiltrative hypovascular HCCs, which are growing in a hypoxic environment. Mol Cancer Ther 2007;6(9):2554–62
EGFRvIII is expressed only in tumor cells and strongly in glioblastoma and is considered a promising target in cancer diagnosis and therapy. Aptamers are synthetic single-stranded oligonucleotides ...that bind to biochemical target molecules with high binding affinity and specificity. This study examined the potential of the 68Ga-NOTA-EGFRvIII aptamer as a nuclear imaging probe for visualizing EGFRvIII-expressing glioblastoma by positron emission tomography (PET). EGFRvIII aptamer was selected using the SELEX technology, and flow cytometry and fluorescence microscopy verified the high binding affinity to EGFRvIII positive U87MG vIII 4.12 glioma cells but not to EGFRvIII negative U87MG cells. The EGFRvIII aptamer was conjugated with a chelator (1,4,7-triazanonane-1,4,7-triyl)triacetic acid (NOTA) for 68Ga-labeling. The 68Ga-NOTA-EGFRvIII aptamer was prepared using the preconcentration-based labeling method with a high radiolabeling yield at room temperature. Ex vivo biodistribution analyses confirmed the significantly higher tumor uptake of the 68Ga-NOTA-EGFRvIII aptamer in EGFRvIII-expressing xenograft tumors than that in EGFRvIII negative tumors, confirming the specific tumor uptake of the 68Ga-NOTA-EGFRvIII aptamer in vivo. PET imaging studies revealed a high retention rate of the 68Ga-NOTA-EGFRvIII aptamer in U87MG vIII 4.12 tumors but only low uptake levels in U87-MG tumors, suggesting that the 68Ga-NOTA-EGFRvIII aptamer may be used as a PET imaging agent for EGFRvIII-expressing glioblastoma.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
The geotechnical characteristics of Ulleung Basin sediments are explored using depressurized samples obtained at 2100
m water depth and 110
m below the sea floor. Geotechnical index tests, X-ray ...diffraction, and SEM images were obtained to identify the governing sediment parameters, chemical composition and mineralogy. We use an instrumented multi-sensor oedometer cell to determine the small-strain stiffness, zero-lateral strain compressibility and electromagnetic properties, and a triaxial device to measure shear strength. SEM images show a sediment structure dominated by microfossils, with some clay minerals that include kaolinite, illite, and chlorite. The preponderant presence of microfossils determines the high porosity of these sediments, defines their microstructure, and governs all macroscale properties. The shear wave velocity increases as the vertical effective stress increases; on the other hand, porosity, permittivity, electrical conductivity, and hydraulic conductivity decrease with increasing confinement. All these parameters exhibit a bi-linear response with effective vertical stress due to the crushable nature of microfossils. Well-established empirical correlations used to evaluate engineering parameters do not apply for these diatomaceous sediments which exhibit higher compressibility than anticipated based on correlations with index properties. Settlements will be particularly important if gas production is attempted using depressurization because this approach will cause both hydrate dissociation and increase in effective stress.
► Diatoms determine a particle size distribution and cause a dual porosity. ► Microfossil structure biases the geotechnical properties. ► Well-established empirical correlations do not apply for diatomaceous sediments. ► Hydrate dissociation and change in effective stress may cause pronounced settlement.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Cholangiocarcinoma has a poor prognosis and is refractory to conventional chemotherapy and radiation therapy. Improving survival of patients with advanced cholangiocarcinoma urgently requires the ...development of new effective targeted therapies in combination with chemotherapy. We previously developed a human monoclonal antibody (mAb) Ab417 that binds to both the human and mouse L1 cell adhesion molecule (L1CAM) with high affinities. In the present study, we observed that Ab417 exhibited tumor targeting ability in biodistribution studies and dose-dependent tumor growth inhibition in an intrahepatic cholangiocarcinoma (Choi-CK) xenograft mouse model. Regarding the mechanism of action, Ab417 was internalized into the tumor cells and thereby down-regulated membrane L1CAM, and inhibited tumor growth by reducing tumor cell proliferation in vivo. Gemcitabine inhibited the tumor growth in a dose-dependent manner in the Choi-CK xenograft model. However, cisplatin inhibited the tumor growth moderately and not in a dose-dependent way, suggesting that the tumors may have developed resistance to apoptosis induced by cisplatin. Combined treatment with Ab417 and gemcitabine or cisplatin exerted enhanced tumor growth inhibition compared to treatment with antibody or drug alone. The results suggest that Ab417 in combination with chemotherapy may have potential as a new therapeutic regimen for cholangiocarcinoma. Our study is the first to show an enhanced therapeutic effect of a therapeutic antibody targeting L1CAM in combination with chemotherapy in cholangiocarcinoma models.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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