Advances in endoscopic and surgical techniques have increased the frequency and complexity of these procedures and associated complications such as gastrointestinal perforation. With the advancements in the field of g...Advances in endoscopic and surgical techniques have increased the frequency and complexity of these procedures and associated complications such as gastrointestinal perforation. With the advancements in the field of gastroenterology, the promising use of an over the scope clips(OTSC) has fulfilled the unmet need for a reliable endoscopic devise in approximation of gastrointestinal perforation. This novel approach has raised the level of confidence in endoscopist in dealing with this serious complication during endoscopy. Here we have shared our experience with OTSC to evaluate its efficacy and safety in managing iatrogenic gastrointestinal perforations during endoscopy.展开更多
With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the requirements.Thus,long-term resilienc...With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the requirements.Thus,long-term resilience and superior energy density associated with self-discharge in SCs are obviously critical,but securing electrode materials,which can meet both benefits of SCs and persist charged potential for a comparatively prolonged duration,are still elusive.Herein,hierarchically refined nickel-sulfide heterostructure(CuO-NS)on CuO(CO)scaffold is achieved through optimized film formation,exhibiting a threefold improvement in the essential electrochemical characteristics and outstanding capacitance retention(∼5%loss).Self-discharge behavior and its mechanism are systematically investigated via morphological control and nanostructural evolution.Furthermore,significant mitigation of self-discharge owing to an increase in surface area and refined nanostructure is displayed.Remarkably,CuO-NS2(20 cycle overcoating)based SC can retain over 60%of the charged potential for a complete voltage holding and a self-discharge test for 16 h.An appealing demonstration of wireless power transmission in burst mode is demonstrated for secure digital(SD)card data writing,powered by SCs,which substantiates that it can be readily leveraged in power management systems.This enables us to realize one of the envisioned applications soon.展开更多
W-Ag has applications in a wide range of cutting-edge fields,counting heat sinks and microwave absorbers for micro—electronic components,electric arc ends,and filaments for welding processes,electrical contacts,and d...W-Ag has applications in a wide range of cutting-edge fields,counting heat sinks and microwave absorbers for micro—electronic components,electric arc ends,and filaments for welding processes,electrical contacts,and durable electronic connections.Chemical methods provide a number of benefits,including improved purity,and controlled particle size.The present study focused on the fabrication of W-Ag nano composites using chemical synthesis.W-Ag nanocomposites with average size less than 50 nm were synthesized using Tungsten hexacarbonyl(W(CO)_(6),and silver acetate(CH_(3)-COOAg)as metal precursors in the present study.The W-Ag composites were sintered using conventional sintering.X-ray diffraction studies of as-prepared powders showed amorphous W-phase and FCC Ag,while sintered W-Ag composites exhibited crystalline BCC W and FCC Ag phase.The effect of sintering temperature on relative density and mechanical properties of W-Ag sintered compacts was investigated.Relative density in excess of 97.6%,98.2%and 98.8%was achieved for W-20.3 wt.%Ag,W-30.1 wt.%Ag and W-39.8 wt.%Ag composites on conventional sintering at 1000℃ for 1 h.Vickers hardness of 364±10 and 320±8 Hv and 279±6 were achieved for W-20.3 wt.%Ag,W-30.1 wt.%Ag and W-39.8 wt.%Ag composite compacts respectively.The hardness value of W-Ag composites decreased with an increase in Ag content.The combination of properties realized in this study renders the composites suitable for automotive and heat sink applications.展开更多
AIM: To evaluate the impact of reporting bowel preparation using Boston Bowel Preparation Scale(BBPS) in clinical practice.METHODS: The study was a prospective observational cohort study which enrolled subjects report...AIM: To evaluate the impact of reporting bowel preparation using Boston Bowel Preparation Scale(BBPS) in clinical practice.METHODS: The study was a prospective observational cohort study which enrolled subjects reporting for screening colonoscopy. All subjects received a gallon of polyethylene glycol as bowel preparation regimen. After colonoscopy the endoscopists determined quality of bowel preparation using BBPS. Segmental scores were combined to calculate composite BBPS. Site and size of the polyps detected was recorded. Pathology reports were reviewed to determine advanced adenoma detection rates(AADR). Segmental AADR's were calculated and categorized based on the segmental BBPS to determine the differential impact of bowel prep on AADR. RESULTS: Three hundred and sixty subjects were enrolled in the study with a mean age of 59.2 years, 36.3% males and 63.8% females. Four subjects with incomplete colonoscopy due BBPS of 0 in any segment were excluded. Based on composite BBPS subjects were divided into 3 groups; Group-0(poor bowel prep, BBPS 0-3) n = 26(7.3%), Group-1(Suboptimal bowel prep, BBPS 4-6) n = 121(34%) and Group-2(Adequate bowel prep, BBPS 7-9) n = 209(58.7%). AADR showed a linear trend through Group-1 to 3; with an AADR of 3.8%, 14.8% and 16.7% respectively. Also seen was a linear increasing trend in segmental AADR with improvement in segmental BBPS. There was statistical significant difference between AADR among Group 0 and 2(3.8% vs 16.7%, P < 0.05), Group 1 and 2(14.8% vs 16.7%, P < 0.05) and Group 0 and 1(3.8% vs 14.8%, P < 0.05). χ2 method was used to compute P value for determining statistical significance.CONCLUSION: Segmental AADRs correlate with segmental BBPS. It is thus valuable to report segmental BBPS in colonoscopy reports in clinical practice.展开更多
Continuous segregation of a binary mixture of heterogeneous （different density） solids is carried out in a gas-solid fluidized bed. We investigate how gas velocity, solids feed rate, flotsam feed composition, bottom...Continuous segregation of a binary mixture of heterogeneous （different density） solids is carried out in a gas-solid fluidized bed. We investigate how gas velocity, solids feed rate, flotsam feed composition, bottom discharge pipe diameter, and minimum fluidization velocity ratio of the flotsam to jetsam parti- cles influence the solids holdup, separation factor, and product quality （flotsam purity at the top outlet）. The results are interpreted in terms of solids holdup information. The results indicate that the separation factor decreases when the gas velocity, bottom discharge pipe diameter, flotsam feed composition, or the minimum fluidization velocity ratio increase, while the separation factor increases as the solids feed rate increases. The product quality decreases when the gas velocity, solids feed rate, or minimum fluidization velocity ratio increase, while the product quality increases as the bottom discharge pipe diameter or flot- sam feed composition increase. Correlations for predicting the separation factor and product quality are proposed using a logistic model for individual flotsam feed compositions, which satisfactorily compares with the present experimental data.展开更多
In this paper, the so-called local likelihood method is suggested for solving thechange point problems when the data are distributed as multivariate normal. Thedetection procedures proposed not only provide strongly e...In this paper, the so-called local likelihood method is suggested for solving thechange point problems when the data are distributed as multivariate normal. Thedetection procedures proposed not only provide strongly eonsistent estimates for thenumber and locations of the change points, but also simplify significantly thecomputation.展开更多
Continuous segregation of binary heterogeneous solids （different density mixtures） is carried out in a gas-solid fluidized bed to study the effects of gas velocity, solids feed rate, feed composition and density dif...Continuous segregation of binary heterogeneous solids （different density mixtures） is carried out in a gas-solid fluidized bed to study the effects of gas velocity, solids feed rate, feed composition and density difference of solids on the separation factor （recovery of flotsam at top outlet） and the quality of the product （purity of flotsam at top outlet） in a continuous fast-fluidized bed. The holdup of the bed material is obtained in each experimental run. It is observed that the separation factor decreases with increase in solids feed rate or density difference of solids, and increases with gas velocity or proportion of flotsam in the feed. The quality of the product decreases with increase in gas velocity or solids flow rate, and increases with feed composition or density difference of solids. The experimental results show that the separation factor and the quality of the product are more sensitive to gas velocity than to other operating parameters, Empirical correlations for predicting the separation factor and quality of the product are proposed based on the Richards model for individual flotsam mass fraction in the feed, and the predictions agree satisfactorily with the present exlgerimental data,展开更多
Hydrodynamics of 3-phase inverse fluidized bed is studied experimentally using low density particles for different liquid and gas velocities. The hydrodynamic characteristics studied include pressure drop, minimum liq...Hydrodynamics of 3-phase inverse fluidized bed is studied experimentally using low density particles for different liquid and gas velocities. The hydrodynamic characteristics studied include pressure drop, minimum liquid and gas fluidization velocities and phase holdups. The minimum liquid fluidization velocity determined using the bed pressure gradient, decreases with increase in gas velocity. The axial profiles of phase holdups shows that the liquid holdup increases along the bed height, whereas the solid holdup decreases down the bed. However, the gas holdup is almost uniform in the bed.展开更多
Sodium fluoride was found to be a simple, mild and efficient catalyst for the synthesis of 2,4- disuhstituted 1,3-thiazoles and selenazoles utilizing phenacyl bromides/3-（2-bromoacetyl）-2H-chro- men-2-one and thiour...Sodium fluoride was found to be a simple, mild and efficient catalyst for the synthesis of 2,4- disuhstituted 1,3-thiazoles and selenazoles utilizing phenacyl bromides/3-（2-bromoacetyl）-2H-chro- men-2-one and thioureaJphenylthiourea/selenourea in aqueous methanol at ambient temperature. Analytically pure products are formed within 1-3 rain in excellent yields.展开更多
A state-of-the art Rayleigh and Mie backscattering lidar was set up at Gadanki （13.5°N, 79.2°E） in the Tropics in India. Using this system, regular observations of upper tropospheric clouds, aerosols at st...A state-of-the art Rayleigh and Mie backscattering lidar was set up at Gadanki （13.5°N, 79.2°E） in the Tropics in India. Using this system, regular observations of upper tropospheric clouds, aerosols at stratospheric heights and atmospheric temperatures in the range from 30 to 80 km were made. In this paper, the data collected during the period of 1998-99 were selected for systematic investigation and presentation. The Mie scattering lidar system is capable of measuring the degree of depolarization in the laser backscattering. Several tropical cirrus cloud structures have been identified with low to moderate ice content. Occasionally, thin sub-visible cirrus clouds in the vicinity of the tropical tropopause have also been detected. The aerosol measurements in the upper troposphere and lower stratosphere show low aerosol content with a vertical distribution up to 35 km altitude. Rayleigh-scattering lidar observations reveal that at the tropical site, temperature inversion occurs at mesospheric heights. Atmospheric waves have induced perturbations in the temperatures for several times at the upper stratospheric heights. A significant warming in the lower mesosphere associated with a consistent cooling in the upper stratospheric heights is observed particularly in the winter season during the events of sudden stratospheric warming （ssw）.展开更多
Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best ...Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best of our knowledge, our group is the only one in Canada leading the research into the properties of nanoparticles, glasses and glass-ceramics for optical refrigeration appli- cations. In the present work, optical properties of 50GeO2- 30PbF2-18PbO-2YbF3 glass-ceramics for laser cooling are presented and discussed as a function of crystallization temperature. Spectroscopic results show that samples have near infrared photoluminescence emission due to the 2F5/2 - 2F7/2 Yb3＋ transition, centered at -1016 nm with an excitation wavelength of 920 nm or 1011 nm, and the highest photoluminescence emission efficiency occurs for heat-treatment for 5 h at 350℃. The internal photolumi- nescence quantum yield varies between 99% and 80%, depending on the temperature of heat-treatment, being the most efficient under 1011 nm excitation. The 2F5/2 lifetime increases from 1.472 to 1.970 ms for heat treatments at 330℃ to 350℃, respectively, due to energy trapping and the low phonon energy of the nanocrystals. The sample temperature dependence was measured with a fiber Bragg grating sensor, as a function of input pump laser wavelength and processing temperature. These measure- ments show that the heating process approaches near zero for an excitation wavelength between 1020 and 1030 nm, which is an indication that phonons are removed effectivelly from the glass-ceramic materials, and they can be used for optical laser cooling applications. On theother hand, the temperature increase as a function of input laser power into samples remains constant between 920 and 980 nm wavelength excitation, a temperature variation of 36 K/W （temperature of 58℃/W） was attained under excitation at 950 nm, showing a possible use for biomedical applications to be explored.展开更多
Objective: To compare the efficacy, safety, and refractive errors of astigmatism after cataract surgery by phacoemulsification andmanual small-incision cataract surgery techniques. Design: Masked randomized control cl...Objective: To compare the efficacy, safety, and refractive errors of astigmatism after cataract surgery by phacoemulsification andmanual small-incision cataract surgery techniques. Design: Masked randomized control clinical trial. Participants: Four hundred eyes of 400 patients, 1:1 randomization with half in each arm of the trial. Methods: A total of 400 eyes was assigned randomly to either phacoemulsification or small-incision groups after informed consent and were operated on by 4 surgeons. They were masked to the technique of surgery before, during, and after cataract surgery and followed up to 1 year after surgery. The intraoperative and postoperative complications, uncorrected and best-corrected visual acuity, and astigmatism were recorded at 1 and 6 weeks postoperatively. Main Outcome Measures: The proportion of patients achieving visual acuity better than or equal to 6/18 with and without spectacles after cataract surgery in the operated eye up to 6 weeks, postoperative astigmatism, and complications during and after surgery. Results: This article reports clinical outcomes up to 6 weeks. Three hundred eighty-three of 400 (95.75%) patients completed the 1-week follow-up, and 372 of 400 (93%) patients completed the 6-week follow-up. One hundred thirty-one of 192 (68.2%) patients in the phacoemulsification group and 117 of 191 (61.25%) patients in the small-incision group had uncorrected visual acuity better than or equal to 6/18 at 1 week (P=0.153). One hundred fifty of 185 (81.08%) patients of the phacoemulsification group and 133 of 187 (71.1%) patients of the small-incision group (P=0.038) were better than or equal to 6/18 at the 6-week follow-up for presenting visual activity. Visual acuity improved to ≤6/18 with best correction in 182 of 185 patients (98.4%) and 184 of 187 (98.4%) patients (P= 0.549), respectively. Poor outcome (postoperative visual acuity < 6/60) was noted in 1 of 185 (0.5%) in the phacoemulsification group and none in the small-incision group. The mode of astigmatism was 0.5 diopte展开更多
The present study describes variation of peak linear depolarization ratio (LDR) with wind around the cloud altitude using simultaneous observation of winds and cirrus cloud for the first time using Indian MST radar an...The present study describes variation of peak linear depolarization ratio (LDR) with wind around the cloud altitude using simultaneous observation of winds and cirrus cloud for the first time using Indian MST radar and polarization lidar co-located over a low latitude station Gadanki (13.7°N and 79.2°E). Three different cases of passage of the cirrus at different altitudes are noticed, one during a North-East monsoon day and other two during South-West monsoon days. The zonal wind below the cloud height has shown similar variation with LDR during 02 November 2006 and the meridional wind within the cloud height during 25 July 2007 and 08 June 2006 has shown opposite variation with LDR. Even though there is a significant increase in zonal wind due to the existence of tropical easterly jet (TEJ) above cloud height during 25 July 2007 and 08 June 2006, also, the vertical wind is found to be continuously varying during 25 July 2007 and it is upward dominant in the initial stage and is mostly downward in the later stage of observation on 08 June 2006, there is a slight descent in cloud altitude only during 25 July 2007. Thus, the wind above the cloud height alone may not affect the ascent/descent of the cloud top altitude. The potential temperature gradient is high within the cloud heights when the cirrus present near the cold point tropopause indicates the maximum air-mass mixing near the tropopause.展开更多
PURPOSE. To determine the distribution of perceived visual ability for functio nal vision performance among persons with low vision in the Indian state of Andh ra Pradesh. METHODS. As part of a population-based epidem...PURPOSE. To determine the distribution of perceived visual ability for functio nal vision performance among persons with low vision in the Indian state of Andh ra Pradesh. METHODS. As part of a population-based epidemiologic study, the And hra Pradesh Eye Disease Study (APEDS), a 16-item visual function questionnaire was designed and applied to 7363 persons older than 15 years, to record the leve ls of difficulty perceived by the subjects. Of these, 123 persons were found to have low vision. Rasch analysis was used to convert the ordinal difficulty ratin gs of these 123 persons into interval measures of perceived visual ability for f unctional vision. RESULTS. Content validity of the questionnaire was demonstrate d by good separation indices (3.17 and 5.44) and high reliability scores (0.91 a nd 0.97) for person and item parameters. Construct validity was shown with model fit statistics. Criterion validity of the questionnaire was shown by good discr imination among the general vision ratings. The functional situation that requir ed the least visual ability was "reaching an object farther or closer than you thought"; the situation requiring the most visual ability was"recognizing smal l objects."Bivariate regression analysis determined that for every unit of logM AR visual acuity, perceived visual ability for functional vision decreased by 2. 9 logit, which could explain 32%of the variability in the person measure. CONCL USIONS. The described assessment, across a range of visual problems, is a valid way to measure perceived ability for functional vision in persons with low visio n. Perceived visual ability varies with every unit of logarithm of the minimum a ngle of resolution (logMAR) visual acuity.展开更多
A rapid, simple and single stereo selective high-performance liquid chromatographic (HPLC) method was developed and validated for enantiomers of palonosetron hydrochloride (PALO) and its process related chiral impurit...A rapid, simple and single stereo selective high-performance liquid chromatographic (HPLC) method was developed and validated for enantiomers of palonosetron hydrochloride (PALO) and its process related chiral impurities. A computer simulating software was used for the development of chiral method. The developed method was able to separate not only the enantiomers of palonosetron hydrochloride but also its process related chiral impurities within 12 min. The chromatographic separation was carried out by normal phase chromatography using a 3 μm column of cellulose based chiral stationary phase (Chiralcel-OD 250mm × 4.6mm) with a mobile phase comprised of n-hexane: ethanol: methanol: heptafluoro butyric acid: diethyl amine (70:15:15:0.05:0.1, v/v) at a flow rate of 1.0 mL/min. The effects of additive concentration as well as nature of polar organic modifier, flow rate, and temperature on enantioselectivity were investigated. The limit of detection (LOD) and limit of quantification (LOQ) of the palonosetron isomers and its related chiral impurities were found to be in the range 0.06-0.10 μg/mL and 0.14 - 0.24 μg/mL respectively. The method showed excellent linearity (R2 > 0.998) over a range of 0.14 to 1.125 μg/mL. The percentage recovery of the isomers in bulk drug samples ranged from 87.0 to 116.0.展开更多
In this paper,the authors consider the problem of change points within the framework of model selection and propose a procedure for estimating the locations of change points when the number of change points is known.... In this paper,the authors consider the problem of change points within the framework of model selection and propose a procedure for estimating the locations of change points when the number of change points is known.The strong consistency of this procedure is also established. The problem of detecting change points is discussed within the framework of the simultaneous test procedure.The case where the number of change points is unknown will be discussed in another paper.展开更多
文摘Advances in endoscopic and surgical techniques have increased the frequency and complexity of these procedures and associated complications such as gastrointestinal perforation. With the advancements in the field of gastroenterology, the promising use of an over the scope clips(OTSC) has fulfilled the unmet need for a reliable endoscopic devise in approximation of gastrointestinal perforation. This novel approach has raised the level of confidence in endoscopist in dealing with this serious complication during endoscopy. Here we have shared our experience with OTSC to evaluate its efficacy and safety in managing iatrogenic gastrointestinal perforations during endoscopy.
基金supported by the Incheon National University Research Grant in 2022,Incheon,Republic of Korea.
文摘With the surge of demand for instant high power in miniaturized electronic and mechanical systems,supercapacitors(SCs)are considered as one of the viable candidates to fulfill the requirements.Thus,long-term resilience and superior energy density associated with self-discharge in SCs are obviously critical,but securing electrode materials,which can meet both benefits of SCs and persist charged potential for a comparatively prolonged duration,are still elusive.Herein,hierarchically refined nickel-sulfide heterostructure(CuO-NS)on CuO(CO)scaffold is achieved through optimized film formation,exhibiting a threefold improvement in the essential electrochemical characteristics and outstanding capacitance retention(∼5%loss).Self-discharge behavior and its mechanism are systematically investigated via morphological control and nanostructural evolution.Furthermore,significant mitigation of self-discharge owing to an increase in surface area and refined nanostructure is displayed.Remarkably,CuO-NS2(20 cycle overcoating)based SC can retain over 60%of the charged potential for a complete voltage holding and a self-discharge test for 16 h.An appealing demonstration of wireless power transmission in burst mode is demonstrated for secure digital(SD)card data writing,powered by SCs,which substantiates that it can be readily leveraged in power management systems.This enables us to realize one of the envisioned applications soon.
文摘W-Ag has applications in a wide range of cutting-edge fields,counting heat sinks and microwave absorbers for micro—electronic components,electric arc ends,and filaments for welding processes,electrical contacts,and durable electronic connections.Chemical methods provide a number of benefits,including improved purity,and controlled particle size.The present study focused on the fabrication of W-Ag nano composites using chemical synthesis.W-Ag nanocomposites with average size less than 50 nm were synthesized using Tungsten hexacarbonyl(W(CO)_(6),and silver acetate(CH_(3)-COOAg)as metal precursors in the present study.The W-Ag composites were sintered using conventional sintering.X-ray diffraction studies of as-prepared powders showed amorphous W-phase and FCC Ag,while sintered W-Ag composites exhibited crystalline BCC W and FCC Ag phase.The effect of sintering temperature on relative density and mechanical properties of W-Ag sintered compacts was investigated.Relative density in excess of 97.6%,98.2%and 98.8%was achieved for W-20.3 wt.%Ag,W-30.1 wt.%Ag and W-39.8 wt.%Ag composites on conventional sintering at 1000℃ for 1 h.Vickers hardness of 364±10 and 320±8 Hv and 279±6 were achieved for W-20.3 wt.%Ag,W-30.1 wt.%Ag and W-39.8 wt.%Ag composite compacts respectively.The hardness value of W-Ag composites decreased with an increase in Ag content.The combination of properties realized in this study renders the composites suitable for automotive and heat sink applications.
文摘AIM: To evaluate the impact of reporting bowel preparation using Boston Bowel Preparation Scale(BBPS) in clinical practice.METHODS: The study was a prospective observational cohort study which enrolled subjects reporting for screening colonoscopy. All subjects received a gallon of polyethylene glycol as bowel preparation regimen. After colonoscopy the endoscopists determined quality of bowel preparation using BBPS. Segmental scores were combined to calculate composite BBPS. Site and size of the polyps detected was recorded. Pathology reports were reviewed to determine advanced adenoma detection rates(AADR). Segmental AADR's were calculated and categorized based on the segmental BBPS to determine the differential impact of bowel prep on AADR. RESULTS: Three hundred and sixty subjects were enrolled in the study with a mean age of 59.2 years, 36.3% males and 63.8% females. Four subjects with incomplete colonoscopy due BBPS of 0 in any segment were excluded. Based on composite BBPS subjects were divided into 3 groups; Group-0(poor bowel prep, BBPS 0-3) n = 26(7.3%), Group-1(Suboptimal bowel prep, BBPS 4-6) n = 121(34%) and Group-2(Adequate bowel prep, BBPS 7-9) n = 209(58.7%). AADR showed a linear trend through Group-1 to 3; with an AADR of 3.8%, 14.8% and 16.7% respectively. Also seen was a linear increasing trend in segmental AADR with improvement in segmental BBPS. There was statistical significant difference between AADR among Group 0 and 2(3.8% vs 16.7%, P < 0.05), Group 1 and 2(14.8% vs 16.7%, P < 0.05) and Group 0 and 1(3.8% vs 14.8%, P < 0.05). χ2 method was used to compute P value for determining statistical significance.CONCLUSION: Segmental AADRs correlate with segmental BBPS. It is thus valuable to report segmental BBPS in colonoscopy reports in clinical practice.
文摘Continuous segregation of a binary mixture of heterogeneous （different density） solids is carried out in a gas-solid fluidized bed. We investigate how gas velocity, solids feed rate, flotsam feed composition, bottom discharge pipe diameter, and minimum fluidization velocity ratio of the flotsam to jetsam parti- cles influence the solids holdup, separation factor, and product quality （flotsam purity at the top outlet）. The results are interpreted in terms of solids holdup information. The results indicate that the separation factor decreases when the gas velocity, bottom discharge pipe diameter, flotsam feed composition, or the minimum fluidization velocity ratio increase, while the separation factor increases as the solids feed rate increases. The product quality decreases when the gas velocity, solids feed rate, or minimum fluidization velocity ratio increase, while the product quality increases as the bottom discharge pipe diameter or flot- sam feed composition increase. Correlations for predicting the separation factor and product quality are proposed using a logistic model for individual flotsam feed compositions, which satisfactorily compares with the present experimental data.
文摘In this paper, the so-called local likelihood method is suggested for solving thechange point problems when the data are distributed as multivariate normal. Thedetection procedures proposed not only provide strongly eonsistent estimates for thenumber and locations of the change points, but also simplify significantly thecomputation.
文摘Continuous segregation of binary heterogeneous solids （different density mixtures） is carried out in a gas-solid fluidized bed to study the effects of gas velocity, solids feed rate, feed composition and density difference of solids on the separation factor （recovery of flotsam at top outlet） and the quality of the product （purity of flotsam at top outlet） in a continuous fast-fluidized bed. The holdup of the bed material is obtained in each experimental run. It is observed that the separation factor decreases with increase in solids feed rate or density difference of solids, and increases with gas velocity or proportion of flotsam in the feed. The quality of the product decreases with increase in gas velocity or solids flow rate, and increases with feed composition or density difference of solids. The experimental results show that the separation factor and the quality of the product are more sensitive to gas velocity than to other operating parameters, Empirical correlations for predicting the separation factor and quality of the product are proposed based on the Richards model for individual flotsam mass fraction in the feed, and the predictions agree satisfactorily with the present exlgerimental data,
文摘Hydrodynamics of 3-phase inverse fluidized bed is studied experimentally using low density particles for different liquid and gas velocities. The hydrodynamic characteristics studied include pressure drop, minimum liquid and gas fluidization velocities and phase holdups. The minimum liquid fluidization velocity determined using the bed pressure gradient, decreases with increase in gas velocity. The axial profiles of phase holdups shows that the liquid holdup increases along the bed height, whereas the solid holdup decreases down the bed. However, the gas holdup is almost uniform in the bed.
基金the Ministry of Human Resource Development for their support
文摘Sodium fluoride was found to be a simple, mild and efficient catalyst for the synthesis of 2,4- disuhstituted 1,3-thiazoles and selenazoles utilizing phenacyl bromides/3-（2-bromoacetyl）-2H-chro- men-2-one and thioureaJphenylthiourea/selenourea in aqueous methanol at ambient temperature. Analytically pure products are formed within 1-3 rain in excellent yields.
文摘A state-of-the art Rayleigh and Mie backscattering lidar was set up at Gadanki （13.5°N, 79.2°E） in the Tropics in India. Using this system, regular observations of upper tropospheric clouds, aerosols at stratospheric heights and atmospheric temperatures in the range from 30 to 80 km were made. In this paper, the data collected during the period of 1998-99 were selected for systematic investigation and presentation. The Mie scattering lidar system is capable of measuring the degree of depolarization in the laser backscattering. Several tropical cirrus cloud structures have been identified with low to moderate ice content. Occasionally, thin sub-visible cirrus clouds in the vicinity of the tropical tropopause have also been detected. The aerosol measurements in the upper troposphere and lower stratosphere show low aerosol content with a vertical distribution up to 35 km altitude. Rayleigh-scattering lidar observations reveal that at the tropical site, temperature inversion occurs at mesospheric heights. Atmospheric waves have induced perturbations in the temperatures for several times at the upper stratospheric heights. A significant warming in the lower mesosphere associated with a consistent cooling in the upper stratospheric heights is observed particularly in the winter season during the events of sudden stratospheric warming （ssw）.
文摘Abstract In recent years, our research group has developed and studied new rare-earth doped materials for the promising technology of solid-state laser cooling, which is based on anti-stokes fluorescence. To the best of our knowledge, our group is the only one in Canada leading the research into the properties of nanoparticles, glasses and glass-ceramics for optical refrigeration appli- cations. In the present work, optical properties of 50GeO2- 30PbF2-18PbO-2YbF3 glass-ceramics for laser cooling are presented and discussed as a function of crystallization temperature. Spectroscopic results show that samples have near infrared photoluminescence emission due to the 2F5/2 - 2F7/2 Yb3＋ transition, centered at -1016 nm with an excitation wavelength of 920 nm or 1011 nm, and the highest photoluminescence emission efficiency occurs for heat-treatment for 5 h at 350℃. The internal photolumi- nescence quantum yield varies between 99% and 80%, depending on the temperature of heat-treatment, being the most efficient under 1011 nm excitation. The 2F5/2 lifetime increases from 1.472 to 1.970 ms for heat treatments at 330℃ to 350℃, respectively, due to energy trapping and the low phonon energy of the nanocrystals. The sample temperature dependence was measured with a fiber Bragg grating sensor, as a function of input pump laser wavelength and processing temperature. These measure- ments show that the heating process approaches near zero for an excitation wavelength between 1020 and 1030 nm, which is an indication that phonons are removed effectivelly from the glass-ceramic materials, and they can be used for optical laser cooling applications. On theother hand, the temperature increase as a function of input laser power into samples remains constant between 920 and 980 nm wavelength excitation, a temperature variation of 36 K/W （temperature of 58℃/W） was attained under excitation at 950 nm, showing a possible use for biomedical applications to be explored.
文摘Objective: To compare the efficacy, safety, and refractive errors of astigmatism after cataract surgery by phacoemulsification andmanual small-incision cataract surgery techniques. Design: Masked randomized control clinical trial. Participants: Four hundred eyes of 400 patients, 1:1 randomization with half in each arm of the trial. Methods: A total of 400 eyes was assigned randomly to either phacoemulsification or small-incision groups after informed consent and were operated on by 4 surgeons. They were masked to the technique of surgery before, during, and after cataract surgery and followed up to 1 year after surgery. The intraoperative and postoperative complications, uncorrected and best-corrected visual acuity, and astigmatism were recorded at 1 and 6 weeks postoperatively. Main Outcome Measures: The proportion of patients achieving visual acuity better than or equal to 6/18 with and without spectacles after cataract surgery in the operated eye up to 6 weeks, postoperative astigmatism, and complications during and after surgery. Results: This article reports clinical outcomes up to 6 weeks. Three hundred eighty-three of 400 (95.75%) patients completed the 1-week follow-up, and 372 of 400 (93%) patients completed the 6-week follow-up. One hundred thirty-one of 192 (68.2%) patients in the phacoemulsification group and 117 of 191 (61.25%) patients in the small-incision group had uncorrected visual acuity better than or equal to 6/18 at 1 week (P=0.153). One hundred fifty of 185 (81.08%) patients of the phacoemulsification group and 133 of 187 (71.1%) patients of the small-incision group (P=0.038) were better than or equal to 6/18 at the 6-week follow-up for presenting visual activity. Visual acuity improved to ≤6/18 with best correction in 182 of 185 patients (98.4%) and 184 of 187 (98.4%) patients (P= 0.549), respectively. Poor outcome (postoperative visual acuity < 6/60) was noted in 1 of 185 (0.5%) in the phacoemulsification group and none in the small-incision group. The mode of astigmatism was 0.5 diopte
文摘The present study describes variation of peak linear depolarization ratio (LDR) with wind around the cloud altitude using simultaneous observation of winds and cirrus cloud for the first time using Indian MST radar and polarization lidar co-located over a low latitude station Gadanki (13.7°N and 79.2°E). Three different cases of passage of the cirrus at different altitudes are noticed, one during a North-East monsoon day and other two during South-West monsoon days. The zonal wind below the cloud height has shown similar variation with LDR during 02 November 2006 and the meridional wind within the cloud height during 25 July 2007 and 08 June 2006 has shown opposite variation with LDR. Even though there is a significant increase in zonal wind due to the existence of tropical easterly jet (TEJ) above cloud height during 25 July 2007 and 08 June 2006, also, the vertical wind is found to be continuously varying during 25 July 2007 and it is upward dominant in the initial stage and is mostly downward in the later stage of observation on 08 June 2006, there is a slight descent in cloud altitude only during 25 July 2007. Thus, the wind above the cloud height alone may not affect the ascent/descent of the cloud top altitude. The potential temperature gradient is high within the cloud heights when the cirrus present near the cold point tropopause indicates the maximum air-mass mixing near the tropopause.
文摘PURPOSE. To determine the distribution of perceived visual ability for functio nal vision performance among persons with low vision in the Indian state of Andh ra Pradesh. METHODS. As part of a population-based epidemiologic study, the And hra Pradesh Eye Disease Study (APEDS), a 16-item visual function questionnaire was designed and applied to 7363 persons older than 15 years, to record the leve ls of difficulty perceived by the subjects. Of these, 123 persons were found to have low vision. Rasch analysis was used to convert the ordinal difficulty ratin gs of these 123 persons into interval measures of perceived visual ability for f unctional vision. RESULTS. Content validity of the questionnaire was demonstrate d by good separation indices (3.17 and 5.44) and high reliability scores (0.91 a nd 0.97) for person and item parameters. Construct validity was shown with model fit statistics. Criterion validity of the questionnaire was shown by good discr imination among the general vision ratings. The functional situation that requir ed the least visual ability was "reaching an object farther or closer than you thought"; the situation requiring the most visual ability was"recognizing smal l objects."Bivariate regression analysis determined that for every unit of logM AR visual acuity, perceived visual ability for functional vision decreased by 2. 9 logit, which could explain 32%of the variability in the person measure. CONCL USIONS. The described assessment, across a range of visual problems, is a valid way to measure perceived ability for functional vision in persons with low visio n. Perceived visual ability varies with every unit of logarithm of the minimum a ngle of resolution (logMAR) visual acuity.
基金The reseach is supported by the U.S. Air Force of Scientific Resseach under Contract F49520-85-C-0008. These authors are also supported by National Natural Science Foundation of China.
文摘A rapid, simple and single stereo selective high-performance liquid chromatographic (HPLC) method was developed and validated for enantiomers of palonosetron hydrochloride (PALO) and its process related chiral impurities. A computer simulating software was used for the development of chiral method. The developed method was able to separate not only the enantiomers of palonosetron hydrochloride but also its process related chiral impurities within 12 min. The chromatographic separation was carried out by normal phase chromatography using a 3 μm column of cellulose based chiral stationary phase (Chiralcel-OD 250mm × 4.6mm) with a mobile phase comprised of n-hexane: ethanol: methanol: heptafluoro butyric acid: diethyl amine (70:15:15:0.05:0.1, v/v) at a flow rate of 1.0 mL/min. The effects of additive concentration as well as nature of polar organic modifier, flow rate, and temperature on enantioselectivity were investigated. The limit of detection (LOD) and limit of quantification (LOQ) of the palonosetron isomers and its related chiral impurities were found to be in the range 0.06-0.10 μg/mL and 0.14 - 0.24 μg/mL respectively. The method showed excellent linearity (R2 > 0.998) over a range of 0.14 to 1.125 μg/mL. The percentage recovery of the isomers in bulk drug samples ranged from 87.0 to 116.0.
基金This project is supported by the National Natural Science Foundation of Chinaby the Air Office of Scientific Research of the United States
文摘 In this paper,the authors consider the problem of change points within the framework of model selection and propose a procedure for estimating the locations of change points when the number of change points is known.The strong consistency of this procedure is also established. The problem of detecting change points is discussed within the framework of the simultaneous test procedure.The case where the number of change points is unknown will be discussed in another paper.
