Dielectric loaded graphene plasmon waveguide (DLGPW) is proposed and investigated. An analytical model based on effective-index method is presented and verified by the finite element method ...simulations. The mode effective index, propagation loss, cutoff wavelength of higher order modes and single-mode operation region were derived at mid-infrared spectral region. By changing Fermi energy level, the propagation properties of fundamental mode could be tuned flexibly. The structure of the DLGPW is simple and easy for fabrication. It provided a new freedom to manipulate the graphene surface plasmons, which may led to new applications in actively tunable integrated optical devices.
Background
Hepatic vein tumour thrombus (HVTT) is a major determinant of survival outcomes for patients with hepatocellular carcinoma (HCC). An Eastern Hepatobiliary Surgery Hospital (EHBH)‐HVTT ...model was established to predict the prognosis of patients with HCC and HVTT after liver resection, in order to identify optimal candidates for liver resection.
Methods
Patients with HCC and HVTT from 15 hospitals in China were included. The EHBH‐HVTT model with contour plot was developed using a non‐linear model in the training cohort, and subsequently validated in internal and external cohorts.
Results
Of 850 patients who met the inclusion criteria, there were 292 patients who had liver resection and 198 who did not in the training cohort, and 124 and 236 in the internal and external validation cohorts respectively. Contour plots for the EHBH‐HVTT model were established to predict overall survival (OS) rates of patients visually, based on tumour diameter, number of tumours and portal vein tumour thrombus. This differentiated patients into low‐ and high‐risk groups with distinct long‐term prognoses in the liver resection cohort (median OS 34·7 versus 12·0 months; P < 0·001), internal validation cohort (32·8 versus 10·4 months; P = 0·002) and external validation cohort (15·2 versus 6·5 months; P = 0·006). On subgroup analysis, the model showed the same efficacy in differentiating patients with HVTT in peripheral and major hepatic veins, the inferior vena cava, or in patients with coexisting portal vein tumour thrombus.
Conclusion
The EHBH‐HVTT model was accurate in predicting prognosis in patients with HCC and HVTT after liver resection. It identified optimal candidates for liver resection among patients with HCC and HVTT, including tumour thrombus in the inferior vena cava, or coexisting portal vein tumour thrombus.
Antecedentes
La trombosis tumoral de la vena hepática (hepatic vein tumour thrombus, HVTT) es un determinante importante de los resultados de supervivencia en pacientes con carcinoma hepatocelular (hepatocellular carcinoma, HCC). Se desarrolló el modelo llamado Eastern Hepatobiliary Surgery Hospital (EHBH)‐HVTT para predecir el pronóstico de los pacientes con HCC y HVTT después de la resección hepática (liver resection, LR), con el fin de identificar los candidatos óptimos para LR entre estos pacientes.
Métodos
Se incluyeron pacientes con HCC y HVTT de 15 hospitales en China. El modelo EHBH‐HVTT con gráfico de contorno se desarrolló utilizando un modelo no lineal en la cohorte de entrenamiento, siendo posteriormente validado en cohortes internas y externas.
Resultados
De 850 pacientes que cumplieron con los criterios de inclusión, hubo 292 pacientes en el grupo LR y 198 pacientes en el grupo no LR en la cohorte de entrenamiento, y 124 y 236 en las cohortes de validación interna y externa. Los gráficos de contorno del modelo EHBH‐HVTT se establecieron para predecir visualmente las tasas de supervivencia global (overall survival, OS) de los pacientes, en función del diámetro del tumor, número de tumores y del trombo tumoral de la vena porta (portal vein tumour thrombus, PVTT). Esto diferenciaba a los pacientes en los grupos de alto y bajo riesgo, con distinto pronóstico a largo plazo en las 3 cohortes (34,7 versus 12,0 meses, 32,8 versus 10,4 meses y 15,2 versus 6,5 meses, P < 0,001). En el análisis de subgrupos, el modelo mostró la misma eficacia en la diferenciación de pacientes con HVTT, con trombo tumoral en la vena cava inferior (inferior vena cava tumour thrombus, IVCTT) o en pacientes con PVTT coexistente.
Conclusión
El modelo EHBH‐HVTT fue preciso para la predicción del pronóstico en pacientes con HCC y HVTT después de la LR. Identificó candidatos óptimos para LR en pacientes con HCC y HVTT, incluyendo IVCTT o PVTT coexistente.
The Eastern Hepatobiliary Surgery Hospital–hepatic vein tumour thrombus (EHBH‐HVTT) model was accurate in predicting prognosis in patients with hepatocellular carcinoma (HCC) and HVTT after liver resection. It identified optimal candidates for liver resection among patients with HCC and HVTT, including inferior vena cava tumour thrombus, or coexisting portal vein tumour thrombus (PVTT).
predicts prognosis
Energetic electron depletions are a notable feature of the nightside Martian upper atmosphere. In this study, we investigate systematically the variations of the occurrence of depletions with both ...internal and external conditions, using the extensive Solar Wind Electron Analyzer measurements made on board the Mars Atmosphere and Volatile Evolution. In addition to the known trends of increasing occurrence with decreasing altitude and increasing magnetic field intensity, our analysis reveals that depletions are more easily observed in regions with near horizontal magnetic fields and under low solar wind (SW) dynamic pressures. We also find that below 160 km, the occurrence increases with increasing CO2 density, a trend mostly visible in weakly magnetized regions. These observations have important implications on the formation of electron depletions: (1) Near strong magnetic anomalies, closed magnetic loops preferentially form and shield the atmosphere from direct access of SW electrons, a process that is modulated by the upstream SW condition; and (2) in weakly magnetized regions, SW electrons precipitate into the atmosphere unhindered, but at sufficiently low altitudes, they are either “absorbed” due to inelastic collisions with ambient neutrals or shielded again in response to a change in magnetic connectivity from open to closed. Our analysis further reveals that both the ionospheric plasma content and thermal electron temperature are reduced in regions with depletions compared to regions without, supporting SW electron precipitation as an important source of external energy driving the variability in the deep nightside Martian upper atmosphere and ionosphere.
Key Points
Electron depletions in the nightside Martian ionosphere are more easily observed in regions with near horizontal magnetic fields
Electron depletions are more easily observed under low solar wind dynamic pressures
Substantially reduced ionospheric plasma content and thermal electron temperature are observed in regions with depletions
Microstructure and hardness of a powder-bed-type selective laser melted Ti–6Al–4V alloy after post heat treatments at from 300 °C to 1020 °C were systematically investigated by using optical ...microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and Vickers hardness (HV) tester. Long columnar original β grains together with the inside dominated parallel acicular martensite in the side view, and chessboard pattern in the top view, were found in the as-received specimen. The subtransus heat treatment does not enable modification of the morphology of the original columnar β grain, only leading to the acicular α′ martensite decomposition into the α platelet and whether surrounded β phase or transformed α′ phase depending on the heating temperature; while the supertransus heat treatment would thoroughly break up the original long columnar β grain, leaving only big original equiaxial β grain filled with the new forming weave-type acicular α′ martensite like the supertransus heat treated wrought specimen. Vickers hardness evolution strictly follows the trend of the microstructural change as the heating temperature increasing, and the double peak phenomenon of the Hardness–Temperature plot should be attributed to substructural refinement effect at around 500 °C, martensitic refinement effect at around 1000 °C, and softening effect resulting from the completely decomposition of the martensite at around 875 °C.
•Heat treatment affects microstructure and hardness of the SLM Ti–6Al–4V alloy.•The as-received alloy is of columnar β grains with the inside acicular martensites.•The as-received martensites decompose into α and β/βt plates during heating.•Double peak phenomenon appears in the Microhardness–Temperature plot.
Melting of solids is a common phenomenon in nature. It is also one of the most important phase transformations in materials science and engineering. In recent years, extensive experimental and ...theoretical investigations in conjunction with computer simulations on melting of solids, with various geometries ranging from bulk forms to nanometer-sized clusters, have greatly enhanced our understanding of the nature of melting. This paper reviewed the up-to-date research results on this classical and cutting-edge topic. Emphasis was made on melting and superheating of nano-sized particles and thin films including thermodynamic and kinetic analyses of the size effect and the interfacial structure effect on melting processes.
Lath martensite is the dominant microstructural feature in quenched low-carbon Fe-C alloys. Its formation mechanism is not clear, despite extensive research. The microstructure of an Fe-0.05 C (wt.%) ...alloy water-quenched at various austenitizing temperatures has been investigated using transmission electron microscopy and a novel lath formation mechanism has been proposed. Body-centered cubic {112}〈111〉-type twin can be retained inside laths in the samples quenched at temperatures from 1050 °C to 1200 °C. The formation mechanism of laths with a twin substructure has been explained based on the twin structure as an initial product of martensitic transformation. A detailed detwinning mechanism in the auto-tempering process has also been discussed, because auto-tempering is inevitable during the quenching of low-carbon Fe-C alloys. The driving force for the detwinning is the instability of ω-Fe(C) particles, which are located only at the twinning boundary region. The twin boundary can move through the ω ↔ bcc transition in which the ω phase region represents the twin boundary.
Hot compression tests of titanium alloy Ti–10V–2Fe–3V were performed at the temperature of 1098–1423K and the strain rate of 0.001–1s−1 to examine the influence of deformation conditions over the ...dynamic recrystallization (DRX) of the Ti-alloy. The experimental results show the occurrence of DRX with the bulging nucleation mechanism as a predominant mechanism in hot deformation of the alloy in β-phase field. Partial grain refinement related to the incompletely DRX happened even after a large strain of 1.6. The simulation based on the established DRX kinetics model and a cellular automaton simulation approach coupled with the metallurgical principles of dynamical recrystallization and the practical parameters was conducted to predict the microstructure evolution with the completely DRX. The effects of strain rate and temperature on the steady state strain, volume fraction of DRX and the steady state grain size in DRX process were studied, and a satisfactory agreement between the predicted and experimental results was obtained. The research thus provides an approach to investigate and predict the DRX and microstructure evolution of Ti-alloys in hot working process.
This work studied the effectiveness of fly ash in removing phosphate from aqueous solution and its related removal mechanism. The adsorption and precipitation of phosphate by fly ash were ...investigated separately in order to evaluate their role in the removal of phosphate. Results showed that the removal of phosphate by fly ash was rapid. The removal percentage of phosphate in the first 5
min reached 68–96% of the maximum removal of phosphate by fly ash. The removal processes of phosphate by fly ash included a fast and large removal representing precipitation, then a slower and longer removal due to adsorption. The adsorption of phosphate on fly ash could be described well by Freundlich isotherm equation. The pH and Ca
2+ concentration of fly ash suspension were decreased with the addition of phosphate, which suggests that calcium phosphate precipitation is a major mechanism of the phosphate removal. Comparison of the relative contribution of the adsorption and precipitation to the total removal of phosphate by fly ash showed that the adsorption accounted for 30–34% of the total removal of phosphate, depending on the content of CaO in fly ash. XRD patterns of the fly ash before and after phosphate adsorption revealed that phosphate salt (CaHPO
4·2H
2O) was formed in the adsorption process. Therefore, the removal of phosphate by fly ash can be attributed to the formation of phosphate precipitation as a brushite and the adsorption on hydroxylated oxides. The results suggested that the use of fly ash could be a promising solution to the removal of phosphate in the wastewater treatment and pollution control.
Background
A major complication related to gastrointestinal (GI) symptoms in diabetic patients is chronic constipation. Constipation has serious negative impacts on quality of life; however, without ...a comprehensive understanding of the disease, currently available treatments cannot provide a cure. Platelet‐derived growth factor receptor alpha‐positive cells (PDGFRα+ cells), which form the SIP syncytium with interstitial cells of Cajal and smooth muscle cells, play important roles in GI motility. In the present study, the contributions of PDGFRα+ cells to diabetes‐induced colonic slow transit were investigated in streptozotocin (STZ)‐induced diabetic mice.
Methods
Western blotting, quantitative PCR, contractile experiments, and intracellular recording were used in the present study.
Key Results
The results demonstrated that the colon length was increased in STZ‐treated mice. The colonic transit of artificial fecal pellets in vitro was significantly delayed in STZ‐treated mice. The mRNA and protein expression of PDGFRα, small‐conductance Ca2+‐activated K channels (SK3), and P2Y1 receptors were increased in the colons of STZ‐treated mice. In contractile experiments, the colonic smooth muscles were more sensitive to the SK3 agonist and antagonist (CyPPA and apamin) and the P2Y1 agonist and antagonist (MRS2365 and MRS2500) in STZ‐treated mice. Intracellular recordings showed the responses of membrane potentials in colonic smooth muscle cells to CyPPA, apamin, MRS2365, and MRS2500 were more sensitive in STZ‐treated mice. The electric field stimulation‐induced P2Y1/SK3‐dependent fast inhibitory junctional potentials (fIJPs) of colonic smooth muscles were more significantly hyperpolarized in STZ‐treated mice.
Conclusions and Inferences
These results suggest that the purinergic neurotransmitters/P2Y1/SK3 signaling pathway is up‐regulated in the diabetic colons, thereby mediating diabetes‐induced colonic slow transit.
This article investigates the contributions of PDGFRα+ cells to diabetes‐induced colonic slow transit in streptozotocin‐induced diabetic mice. The colonic smooth muscles were more sensitive to apamin (the SK3 antagonist) in STZ‐treated mice, indicating that the functionally up‐regulated SK3 channels exerted more inhibitory effects on the colonic motility.
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