Objective: A new indirect composite restorative system with water combingpressure, light, and heat was introduced for the fabrication of inlays and onlays. Methods: Fifteendefected teeth were selected for composite re...Objective: A new indirect composite restorative system with water combingpressure, light, and heat was introduced for the fabrication of inlays and onlays. Methods: Fifteendefected teeth were selected for composite resin inlay and onlay fabrication with Tescera ATL unitequipment. The clinical trial was carried out for 3 months. Results: After 3 months test, 7parameters were checked, 15 Tescera inlays and onlays were demonstrated that exceptional esthetics,all 7 parameters were good and the patients were very satisfied. Conclusion: inlays , which weremade with Tescera ATL restorative system, are esthetics; physical properties of materials areimproved highly, and have a long-lasting durability. This restorative system is worthy to be usedand further studied in dental practice.展开更多
Acute coronary syndromes （ACS） are the leading causes of death in the elderly. The suspicion and diagnosis of ACS in this age group is more difficult, since typical angina is less frequent. The morbidity and mortali...Acute coronary syndromes （ACS） are the leading causes of death in the elderly. The suspicion and diagnosis of ACS in this age group is more difficult, since typical angina is less frequent. The morbidity and mortality is greater in older age patients presenting ACS. Despite the higher prevalence and greater risk, elderly patients are underrepresented in major clinical trials fi：om which evidence based recommendations are formulated. The authors describe, in this article, the challenges in the diagnosis and management of ST elevation myocardial infarction in the elderly, and discuss the available evidence.展开更多
Background： The aim of the research was to evaluate the association between CRP （C-reactive protein）, troponin I, d-dimer, creatinine, glucose, GFR （glomerular filtration rate） and LDL-C （low-density lipoprotei...Background： The aim of the research was to evaluate the association between CRP （C-reactive protein）, troponin I, d-dimer, creatinine, glucose, GFR （glomerular filtration rate） and LDL-C （low-density lipoprotein cholesterol） levels at the admission and the results of thrombolytic therapy. Materials and methods： 113 patients who underwent thrombolytic therapy for acute ischemic stroke in Pauls Stradins Clinical University Hospital from 01.01.2015 to 01.01.2016 were studied retrospectively. Blood samples were collected in the emergency department. The neurological status was estimated using the NIHSS （National Institute of Health Stroke Scale）. The efficacy of thrombolytic therapy was assessed by comparing NIHSS score at the admission and after treatment. Afterward all patients were divided into three groups-the major improvement （NIHSS 〉 4）, minor improvement （NIHSS ≤ 4） and without any clinical effect. Results： Only the median levels of GFR were significantly （p = 0.015） lower in patients who did not have any clinical improvements after thrombolytic therapy as compared to patients with the major or minor improvements （60.0, IQR （interquartile range） 42.4-72.3 mL/min/1.73m2; 83.2, IQR 65.3-98.3 mL/min/1.73m2 and 75.9, IQR 59.2-94.6 mL/min/1.73m2）. Based on the ROC （receiver operating characteristic） curve, the optimal cut-off value of GFR level as an indicator for prediction of worsen clinical outcome after thrombolytic therapy was projected to be 61.65 mL/min/1.73m2, which yielded a sensitivity of 71.4% and a specificity of 24.5%, the area under the curve was 0.788 （95% CI （confidence interval）, 0.648-0.928）. According Spearman rank correlation test was founded statistically significant indirect correlation between GFR level and NIHSS score after treatment （r = -0.410, p = 0.020） in patients with severe stroke （NIHSS 〉 14）. Conclusions： GFR level lower than 61.65 mL/min/1.73m2 at the admission could predict as a worse outcome, especially in patients with severe stroke.展开更多
In the present study, we developed a multi-component one-dimensional mathematical model for simulation and optimisation of a commercial catalytic slurry reactor for the direct synthesis of dimethyl ether （DME） from ...In the present study, we developed a multi-component one-dimensional mathematical model for simulation and optimisation of a commercial catalytic slurry reactor for the direct synthesis of dimethyl ether （DME） from syngas and CO2, operating in a churn-turbulent regime. DME productivity and CO conversion were optimised by tuning operating conditions, such as superficial gas velocity, catalyst concentration, catalyst mass over molar gas flow rate （W/F）, syngas composition, pressure and temperature. Reactor modelling was accomplished utilising mass balance, global kinetic models and heterogeneous hydrodynamics. In the heterogeneous flow regime, gas was distributed into two bubble phases： small and large. Simulation results were validated using data obtained from a pilot plant. The developed model is also applicable for the design of large-scale slurry reactors.展开更多
In the last several decades, circulating fluidized bed reactors have been studied in many aspects including hydrodynamics, heat and mass transfer and gas–solid two phase contacting. However, despite the abundance of ...In the last several decades, circulating fluidized bed reactors have been studied in many aspects including hydrodynamics, heat and mass transfer and gas–solid two phase contacting. However, despite the abundance of review papers on hydrodynamics, there is no summary paper on gas–solid contact efficiency to date, especially on high density circulating fluidized beds(CFBs). This paper gives an introduction to, and a review of the measurement of contact efficiency in circulating fluidized bed riser. Firstly, the popular testing method of contact efficiency including the method of heating transfer experiment and hot model reaction are discussed, then previous published papers are reviewed based on the discussed methods. Some key results of the experimental work are described and discussed. Gas–solid contact efficiency is affected by the operating conditions as well as the particle size distribution. The result of the contact efficiency shows that the CFB riser is far away from an ideal plug flow reactor due to the characteristics of hydrodynamics in the riser. Lacunae in the available literature have been delineated and recommendations have been made for further work.展开更多
This paper maintains that when photons enter the pupil and reach the Inner Limiting Membrane （ILM）, they are reflected onto a point or centroid of the vitreous body, which could be the lens, to be transmitted by the...This paper maintains that when photons enter the pupil and reach the Inner Limiting Membrane （ILM）, they are reflected onto a point or centroid of the vitreous body, which could be the lens, to be transmitted by the Muiller cells to the Retinal Pigment Epithelium （RPE） hexagonal cells, where an almost complete image is formed in each of them, overlapping with the adjacent images, to be carried subsequently by each of the ganglion cell axons to a place where the single image we are aware of is formed. This process calls for a high degree of control and coordination, which must be effected by the horizontal, amacrine, and interplexiform cells, gap junctions and the feedback provided from the V1 area to the Lateral Geniculate Nucleus （LGN）. But, as the ILM covers the optic disc but not the fovea, the latter must produce the blind spot and the rays reflected radially from the centroid must have the same centre as the Muller cells in order to be able to channel them to the RPE cells.展开更多
A new combined desulfurization/denitration (DeSOx/DeNOx,) process was tested in this study. The process uses the so-called powder-particle fluidized bed (PPFB) as the major reactor in which a coarse DeNOx catalyst, se...A new combined desulfurization/denitration (DeSOx/DeNOx,) process was tested in this study. The process uses the so-called powder-particle fluidized bed (PPFB) as the major reactor in which a coarse DeNOx catalyst, several hundred micrometers in size, is fluidized by flue gas as the fluidization medium particles, while a continuously supplied fine DeSOx sorbent, several to tens of micrometers in diameter, is entrained with the flue gas. Ammonia for NOx reduction is fed to the bottom of the bed, thus, SOX and NOX are simultaneously removed in the single reactor. By adopting a model gas, SO2-NO-H2O-N2-air, to simulate actual flue gas in a laboratory-scale PPFB, simultaneous SO2 and NO removals were explored with respect to various gas components of flue gas. It was found that the variations of SO2 removal with concentrations (fractions) of oxygen, water vapor, SO2 and NO in flue gas are little affected by the simultaneous NOx reduction. However, the dependencies of NO removal upon such gas components are closely related to the inter-actions between DeSOx sorbent and DeNOx catalyst.展开更多
This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and c...This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and concentration profiles in transient state. The mathematical model is developed for a fluidized bed solar reactor, taking into account dynamics conditions of heating and reaction. The heating was simulated for radiated flux with a normal distribution over lateral walls and with distributed flow conditions of the focal stain. The contraction and expansion effects of the bed were involved with a two dimensional distribution. The mathematical model of a solar fluidized bed reactor involves a reversible chemistry reaction of thermal dissociation of the zinc sulfate （ZnSO4）, also the mathematical model is accomplished by a sensitivity study with regard to the gas inlet temperature and radiation flux.展开更多
To assess the feasibility of biogenic schwertmannite to act as a sorbent for removing arsenite from groundwater, a series of biogenic schwertmannite-packed column adsorption experiments were conducted on simulated As...To assess the feasibility of biogenic schwertmannite to act as a sorbent for removing arsenite from groundwater, a series of biogenic schwertmannite-packed column adsorption experiments were conducted on simulated As（III）-containing groundwater. Empty bed contact time （EBCT）, As（III） concentration in effluent, and the removal efficiency of As（III） through the column were investigated at pH 8.0 and temperature 25 ± 0.5 ℃. The results showed that the breakthrough curves were mainly dependent on EBCT values when the influent As（III） concentration was 500 μg L-1 and the optimum EBCT was 4.0 min. When the effluent As（III） concentration reached 10 and 50 μg L-1, the breakthrough volumes for the schwertmannite adsorption column were 4200 and 5600 bed volume （BV）, with As（III） adsorption capacity of 2.1 and 2.8 mg g-1, respectively. Biogenic schwertmannite could be regenerated by 1.0 mol L-1 NaOH solution, and more than 80% of As（III） adsorbed on the surface of schwertmannite could be released after 3 successive regenerations. The breakthrough volume for the regenerated sehwertmannite-packed column still maintained 4 000-4 200 BV when the As（III） concentration in effluent was below 10 μg L-1. Compared with other sorbents for As（III） removal, the biogenic schwertmannite- packed column had a higher breakthrough volume and a much higher adsorption capacity, implying that biogenic schwertmannite was a highly efficient and potential sorbent to purify As（III）-contaminated groundwater.展开更多
Objective: To sutdy the mechanical properties and the clinical results of minimum-contact plate in the treatment of fractures. Methods: Four-point bending and torsion tests were conducted to compare the new minimum co...Objective: To sutdy the mechanical properties and the clinical results of minimum-contact plate in the treatment of fractures. Methods: Four-point bending and torsion tests were conducted to compare the new minimum contact plate (MCP) with dynamic compression plate (DCP) and limited contact dynamic compression plate (LC-DCP). The fracture healing time and growth of bony callus were observed in 29 cases of long bone fracture fixed with MCP to evaluate the advantages of this kind of plate. Results: The 29 patients who underwent MCP were followed up from 6 to 14 months. The average healing time for femoral, tibial and humeral fractures was 12, 13 and 10 weeks, respectively. All fractures were healed. No displacement of fracture, screw pullout, deformation or break of the plate were found. Conclusions: The bending stiffness of MCP is significantly greater than that of DCP and LC-DCP (P< 0.05). MCP can protect the periosteal blood supply against avascular osseous necrosis and accelerate bone healing. It is a kind of reliable and effective plate in treatment of fractures.展开更多
文摘Objective: A new indirect composite restorative system with water combingpressure, light, and heat was introduced for the fabrication of inlays and onlays. Methods: Fifteendefected teeth were selected for composite resin inlay and onlay fabrication with Tescera ATL unitequipment. The clinical trial was carried out for 3 months. Results: After 3 months test, 7parameters were checked, 15 Tescera inlays and onlays were demonstrated that exceptional esthetics,all 7 parameters were good and the patients were very satisfied. Conclusion: inlays , which weremade with Tescera ATL restorative system, are esthetics; physical properties of materials areimproved highly, and have a long-lasting durability. This restorative system is worthy to be usedand further studied in dental practice.
文摘Acute coronary syndromes （ACS） are the leading causes of death in the elderly. The suspicion and diagnosis of ACS in this age group is more difficult, since typical angina is less frequent. The morbidity and mortality is greater in older age patients presenting ACS. Despite the higher prevalence and greater risk, elderly patients are underrepresented in major clinical trials fi：om which evidence based recommendations are formulated. The authors describe, in this article, the challenges in the diagnosis and management of ST elevation myocardial infarction in the elderly, and discuss the available evidence.
文摘Background： The aim of the research was to evaluate the association between CRP （C-reactive protein）, troponin I, d-dimer, creatinine, glucose, GFR （glomerular filtration rate） and LDL-C （low-density lipoprotein cholesterol） levels at the admission and the results of thrombolytic therapy. Materials and methods： 113 patients who underwent thrombolytic therapy for acute ischemic stroke in Pauls Stradins Clinical University Hospital from 01.01.2015 to 01.01.2016 were studied retrospectively. Blood samples were collected in the emergency department. The neurological status was estimated using the NIHSS （National Institute of Health Stroke Scale）. The efficacy of thrombolytic therapy was assessed by comparing NIHSS score at the admission and after treatment. Afterward all patients were divided into three groups-the major improvement （NIHSS 〉 4）, minor improvement （NIHSS ≤ 4） and without any clinical effect. Results： Only the median levels of GFR were significantly （p = 0.015） lower in patients who did not have any clinical improvements after thrombolytic therapy as compared to patients with the major or minor improvements （60.0, IQR （interquartile range） 42.4-72.3 mL/min/1.73m2; 83.2, IQR 65.3-98.3 mL/min/1.73m2 and 75.9, IQR 59.2-94.6 mL/min/1.73m2）. Based on the ROC （receiver operating characteristic） curve, the optimal cut-off value of GFR level as an indicator for prediction of worsen clinical outcome after thrombolytic therapy was projected to be 61.65 mL/min/1.73m2, which yielded a sensitivity of 71.4% and a specificity of 24.5%, the area under the curve was 0.788 （95% CI （confidence interval）, 0.648-0.928）. According Spearman rank correlation test was founded statistically significant indirect correlation between GFR level and NIHSS score after treatment （r = -0.410, p = 0.020） in patients with severe stroke （NIHSS 〉 14）. Conclusions： GFR level lower than 61.65 mL/min/1.73m2 at the admission could predict as a worse outcome, especially in patients with severe stroke.
文摘In the present study, we developed a multi-component one-dimensional mathematical model for simulation and optimisation of a commercial catalytic slurry reactor for the direct synthesis of dimethyl ether （DME） from syngas and CO2, operating in a churn-turbulent regime. DME productivity and CO conversion were optimised by tuning operating conditions, such as superficial gas velocity, catalyst concentration, catalyst mass over molar gas flow rate （W/F）, syngas composition, pressure and temperature. Reactor modelling was accomplished utilising mass balance, global kinetic models and heterogeneous hydrodynamics. In the heterogeneous flow regime, gas was distributed into two bubble phases： small and large. Simulation results were validated using data obtained from a pilot plant. The developed model is also applicable for the design of large-scale slurry reactors.
基金Supported by the Scientific Research Funds from China University of Petroleum(Beijing)(No.2462014YJRC018)partially supported by the National Natural Science Foundation of China(No.21506253 and No.91534204)
文摘In the last several decades, circulating fluidized bed reactors have been studied in many aspects including hydrodynamics, heat and mass transfer and gas–solid two phase contacting. However, despite the abundance of review papers on hydrodynamics, there is no summary paper on gas–solid contact efficiency to date, especially on high density circulating fluidized beds(CFBs). This paper gives an introduction to, and a review of the measurement of contact efficiency in circulating fluidized bed riser. Firstly, the popular testing method of contact efficiency including the method of heating transfer experiment and hot model reaction are discussed, then previous published papers are reviewed based on the discussed methods. Some key results of the experimental work are described and discussed. Gas–solid contact efficiency is affected by the operating conditions as well as the particle size distribution. The result of the contact efficiency shows that the CFB riser is far away from an ideal plug flow reactor due to the characteristics of hydrodynamics in the riser. Lacunae in the available literature have been delineated and recommendations have been made for further work.
文摘This paper maintains that when photons enter the pupil and reach the Inner Limiting Membrane （ILM）, they are reflected onto a point or centroid of the vitreous body, which could be the lens, to be transmitted by the Muiller cells to the Retinal Pigment Epithelium （RPE） hexagonal cells, where an almost complete image is formed in each of them, overlapping with the adjacent images, to be carried subsequently by each of the ganglion cell axons to a place where the single image we are aware of is formed. This process calls for a high degree of control and coordination, which must be effected by the horizontal, amacrine, and interplexiform cells, gap junctions and the feedback provided from the V1 area to the Lateral Geniculate Nucleus （LGN）. But, as the ILM covers the optic disc but not the fovea, the latter must produce the blind spot and the rays reflected radially from the centroid must have the same centre as the Muller cells in order to be able to channel them to the RPE cells.
文摘A new combined desulfurization/denitration (DeSOx/DeNOx,) process was tested in this study. The process uses the so-called powder-particle fluidized bed (PPFB) as the major reactor in which a coarse DeNOx catalyst, several hundred micrometers in size, is fluidized by flue gas as the fluidization medium particles, while a continuously supplied fine DeSOx sorbent, several to tens of micrometers in diameter, is entrained with the flue gas. Ammonia for NOx reduction is fed to the bottom of the bed, thus, SOX and NOX are simultaneously removed in the single reactor. By adopting a model gas, SO2-NO-H2O-N2-air, to simulate actual flue gas in a laboratory-scale PPFB, simultaneous SO2 and NO removals were explored with respect to various gas components of flue gas. It was found that the variations of SO2 removal with concentrations (fractions) of oxygen, water vapor, SO2 and NO in flue gas are little affected by the simultaneous NOx reduction. However, the dependencies of NO removal upon such gas components are closely related to the inter-actions between DeSOx sorbent and DeNOx catalyst.
文摘This work provides information for an optimal design of a thermochemical storage system, through a proposed mathematical model that predicts the behavior of a solar fluidized bed receiver finding the temperature and concentration profiles in transient state. The mathematical model is developed for a fluidized bed solar reactor, taking into account dynamics conditions of heating and reaction. The heating was simulated for radiated flux with a normal distribution over lateral walls and with distributed flow conditions of the focal stain. The contraction and expansion effects of the bed were involved with a two dimensional distribution. The mathematical model of a solar fluidized bed reactor involves a reversible chemistry reaction of thermal dissociation of the zinc sulfate （ZnSO4）, also the mathematical model is accomplished by a sensitivity study with regard to the gas inlet temperature and radiation flux.
基金Supported by the National Natural Science Foundation of China.(Nos.40930738 and 21077053)
文摘To assess the feasibility of biogenic schwertmannite to act as a sorbent for removing arsenite from groundwater, a series of biogenic schwertmannite-packed column adsorption experiments were conducted on simulated As（III）-containing groundwater. Empty bed contact time （EBCT）, As（III） concentration in effluent, and the removal efficiency of As（III） through the column were investigated at pH 8.0 and temperature 25 ± 0.5 ℃. The results showed that the breakthrough curves were mainly dependent on EBCT values when the influent As（III） concentration was 500 μg L-1 and the optimum EBCT was 4.0 min. When the effluent As（III） concentration reached 10 and 50 μg L-1, the breakthrough volumes for the schwertmannite adsorption column were 4200 and 5600 bed volume （BV）, with As（III） adsorption capacity of 2.1 and 2.8 mg g-1, respectively. Biogenic schwertmannite could be regenerated by 1.0 mol L-1 NaOH solution, and more than 80% of As（III） adsorbed on the surface of schwertmannite could be released after 3 successive regenerations. The breakthrough volume for the regenerated sehwertmannite-packed column still maintained 4 000-4 200 BV when the As（III） concentration in effluent was below 10 μg L-1. Compared with other sorbents for As（III） removal, the biogenic schwertmannite- packed column had a higher breakthrough volume and a much higher adsorption capacity, implying that biogenic schwertmannite was a highly efficient and potential sorbent to purify As（III）-contaminated groundwater.
文摘Objective: To sutdy the mechanical properties and the clinical results of minimum-contact plate in the treatment of fractures. Methods: Four-point bending and torsion tests were conducted to compare the new minimum contact plate (MCP) with dynamic compression plate (DCP) and limited contact dynamic compression plate (LC-DCP). The fracture healing time and growth of bony callus were observed in 29 cases of long bone fracture fixed with MCP to evaluate the advantages of this kind of plate. Results: The 29 patients who underwent MCP were followed up from 6 to 14 months. The average healing time for femoral, tibial and humeral fractures was 12, 13 and 10 weeks, respectively. All fractures were healed. No displacement of fracture, screw pullout, deformation or break of the plate were found. Conclusions: The bending stiffness of MCP is significantly greater than that of DCP and LC-DCP (P< 0.05). MCP can protect the periosteal blood supply against avascular osseous necrosis and accelerate bone healing. It is a kind of reliable and effective plate in treatment of fractures.
